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Reghunandanan, Vallath; Reghunandanan, Rajalaxmy
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There has been extensive research in the recent past looking into the molecular basis and mechanisms of the biological clock, situated in the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. Neurotransmitters are a very important component of SCN function. Thorough knowledge of neurotransmitters is not only essential for the understanding of the clock but also for the successful manipulation of the clock with experimental chemicals and therapeutical drugs. This article reviews the current knowledge about neurotransmitters in the SCN, including neurotransmitters that have been identified only recently. An attempt was made to describe the neurotransmitters and hormonal/diffusible signals of the SCN efference, which are necessary for the master clock to exert its overt function. The expression of robust circadian rhythms depends on the integrity of the biological clock and on the integration of thousands of individual cellular clocks found in the clock. Neurotransmitters are required at all levels, at the input, in the clock itself, and in its efferent output for the normal function of the clock. The relationship between neurotransmitter function and gene expression is also discussed because clock gene transcription forms the molecular basis of the clock and its working.
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Tam, Sheh May; Lefebvre, Véronique; Palloix, Alain; Sage-Palloix, Anne-Marie; Mhiri, Corinne; Grandbastien, Marie-Angèle
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Plant genetic resources often constitute the foundation of successful breeding programs. Pepper (Capsicum annuum L.) is one of the most economically important and diversely utilized Solanaceous crop species worldwide, but less studied compared to tomato and potato. We developed and used molecular markers based on two copia-type retrotransposons, Tnt1 and T135, in a set of Capsicum species and wild relatives from diverse geographical origins. Results showed that Tnt1 and T135 insertion polymorphisms are very useful for studying genetic diversity and relationships within and among pepper species. Clusters of accessions correspond to cultivar types based on fruit shape, pungency, geographic origin and pedigree. Genetic diversity values, normally reflective of past transposition activity and population dynamics, showed positive correlation with the average number of insertions per accession. Similar evolutionary relationships are observed to that inferred by previous karyosystematics studies. These observations support the possibility that retrotransposons have contributed to genome inflation during Capsicum evolution.
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Miah, G.; Rafii, M. Y.; Ismail, M. R.; Puteh, A. B.; Rahim, H. A.; Asfaliza, R.; Latif, M. A.
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Blast disease caused by the fungal pathogen Magnaporthe oryzae is the most severe diseases of rice. Using classical plant breeding techniques, breeders have developed a number of blast resistant cultivars adapted to different rice growing regions worldwide. However, the rice industry remains threatened by blast disease due to the instability of blast fungus. Recent advances in rice genomics provide additional tools for plant breeders to improve rice production systems that would be environmentally friendly. This article outlines the application of conventional breeding, tissue culture and DNA-based markers that are used for accelerating the development of blast resistant rice cultivars. The best way for controlling the disease is to incorporate both qualitative and quantitative genes in resistant variety. Through conventional and molecular breeding many blast-resistant varieties have been developed. Conventional breeding for disease resistance is tedious, time consuming and mostly dependent on environment as compare to molecular breeding particularly marker assisted selection, which is easier, highly efficient and precise. For effective management of blast disease, breeding work should be focused on utilizing the broad spectrum of resistance genes and pyramiding genes and quantitative trait loci. Marker assisted selection provides potential solution to some of the problems that conventional breeding cannot resolve. In recent years, blast resistant genes have introgressed into Luhui 17, G46B, Zhenshan 97B, Jin 23B, CO39, IR50, Pusa1602 and Pusa1603 lines through marker assisted selection. Introduction of exotic genes for resistance induced the occurrence of new races of blast fungus, therefore breeding work should be concentrated in local resistance genes. This review focuses on the conventional breeding to the latest molecular progress in blast disease resistance in rice. This update information will be helpful guidance for rice breeders to develop durable blast resistant rice variety through marker assisted selection.
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Mat Hassan, Hasnuri; Marschner, Petra; McNeill, Ann; Tang, Caixian
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Legumes have been shown to increase P uptake of the following cereal, but the underlying mechanisms are unclear. The aim of this study was to compare the effect of legume pre-crops and their residues on the growth, P uptake and size of soil P pools in the rhizosphere of the following wheat. Three grain legumes (faba bean, chickpea and white lupin) were grown until maturity in loamy sand soil with low P availability to which 80 mg P kg−1 was supplied. This pre-crop soil was then amended with legume residues or left un-amended and planted with wheat. The growth, P uptake and concentrations of P pools in the rhizosphere of the following wheat were measured 6 weeks after sowing. In a separate experiment, residue decomposition was measured over 42 days by determining soil CO2 release as well as available N and P. Decomposition rates were highest for chickpea residues and lowest for wheat residues. P release was greatest from white lupin residues and N release was greatest from faba bean residues, while wheat residues resulted in net N and P immobilisation. The growth of the following wheat was greater in legume pre-crop soil without residue than in soils with residue addition, while the reverse was true for plant P concentration. Among the legumes, faba bean had the strongest effect on growth, P uptake and concentrations of the rhizosphere P pools of the following wheat. Regardless of the pre-crop and residue treatment, wheat depleted the less labile pools residual P as well as NaOH-Pi and Po, with a stronger depletion of the organic pool. We conclude that although P in the added residues may become available during decomposition, the presence of the residues in the soil had a negative effect on the growth of the following wheat. Further, pre-crops or their residues had little effect on the size of P pools in the rhizosphere of wheat.
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Tohmura, Shin-ichiro; Inoue, Akio; Sahari, Siti Hanim
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The effect of melamine content in melamine-urea-formaldehyde (MUF) resins on the formaldehyde emission and resin structure was investigated using six MUF resins synthesized with different F/(M + U) and M/U molar ratios. The formaldehyde emission from the plywood decreased as the F/(M + U) molar ratio decreased and the M/ U molar ratio increased. In addition, the bond performance was enhanced as the M/U molar ratio increased in the MUF resins with a fixed F/(M + U) molar ratio. Quantitative solution13C-NMR spectra of MUF resins revealed that the MUF resins with a high melamine content consisted of more highly branched crosslinkage structure and free melamine compared to the resins with low melamine contents. Furthermore, solid-state13C CP-MAS NMR spectra of cured MUF resins proved that more methylol groups, dimethylene ether, and branched methylene structures were present in the MUF resins with a higher F/(M + U) molar ratio, leading to increased bond strength and formaldehyde emission. There is no significant difference in the linkage structure of the cured resins with the same F/(M + U) and different M/U molar ratios except the ratios of carbonyl carbon of urea and triazine carbon of melamine. Therefore, the lower formaldehyde emission from cured MUF resins with a higher M/U molar ratio might be ascribed to the stronger linkages between triazine carbons of melamine than those of urea carbons. Consequently, the melamine contributed to strong crosslinking linkages in the cured resin structures, leading to lower formaldehyde emission and better bond performance.
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Shahjahan, M.; Jalani, B. S.; Zakri, A. H.; Imbe, T.; Othman, O.
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From a large number of rice varieties tested, no variety was identified as resistant to tungro bacilliform virus (RTBV). Only in Utri Merah was the RTBV multiplication restrictive, whereas other varieties such as Kataribhog and Pankhari 203 were identified as tolerant. These varieties were crossed with a susceptible variety. TN1, to study the inheritance of restrictive multiplication and tolerance to RTBV. After 3 weeks of inoculation with RTBV, F1; F2, and F3 progenies were assessed by enzyme-linked immunosorbent assay (ELISA). The RTBV concentration in all F1 populations was intermediate between parents. The frequency distribution of F2 seedlings with various levels of RTBV concentration indicated that the RTBV tolerance is controlled by multiple genes. The RTBV concentrations in F1 and F2 progenies from the Utri Merah x TN1 cross revealed that restrictive multiplication of RTBV in Utri Merah is a polygenic character. The continuous variation observed in F2 populations from crosses between tolerant varieties and Utri merah indicated no allelic relationships between tolerant and restrictive multiplication traits.
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Leong, Chee Chiew; Shen, Teh-Chien
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Studies of the inactivation of the rice nitrate reductase showed that the nitrate-reducing moiety and not the diaphorase moiety was reversibly inactivated by NADH and cyanide. Ferricyanide could reverse the inactivation, and nitrate could protect the enzyme against inactivation. Although the general characteristics of the reversible inactivation of rice nitrate reductase appeared similar to those of the algal nitrate reductase, it was found that the rice enzyme was automatically reactivated when NADH and cyanide were removed. Attempts to isolate inactivated nitrate reductase from ammonium-treated tissue were unsuccessful.
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Shukor, M. Y.; Rahman, M. F.; Suhaili, Z.; Shamaan, N. A.; Syed, M. A.
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A local molybdenum-reducing bacterium was isolated and tentatively identified as Acinetobacter calcoaceticus strain Dr.Y12 based on carbon utilization profiles using Biolog GN plates and 16S rDNA comparative analysis. Molybdate reduction was optimized under conditions of low dissolved oxygen (37 °C and pH 6.5). Of the electron donors tested, glucose, fructose, maltose and sucrose supported molybdate reduction after 1 d of incubation, glucose and fructose supporting the highest Mo-blue production. Optimum Mo-blue production was reached at 20 mmol/L molybdate and 5 mmol/L phosphate; increasing the phosphate concentrations inhibited the production. An increase in an overall absorption profiles, especially at peak maximum at 865 nm and the shoulder at 700 nm, was observed in direct correlation with the increased in Mo-blue amounts. Metal ions, such as chromium, cadmium, copper, mercury and lead (2 mmol/L final concentration) caused ≈88, 53, 80, 100, and 20 % inhibition, respectively. Respiratory inhibitors, such as antimycin A, rotenone, sodium azide and cyanide showed in this bacterium no inhibition of the Mo-blue production, suggesting that the electron transport system is not a site of molybdate reduction.
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Goh, D. K. S.; Michaux-Ferrière, N.; Monteuuis, O.; Bon, M. -C.
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Somatic embryogenesis of Calamus manan, a single-stemmed rattan species, in tissue culture was scientifically demonstrated for the first time. Root tips of in vitro plantlets produced friable callus when the explants were cultivated for several mo. on a Murashige and Skoog induction medium containing 7.5 mg Picloram per l (31.1 µM). Histological analyses established the presence of proembryos within the callus which differentiated subsequently into somatic embryos using the same culture medium. Histological examination revealed that these somatic embryos completely lacked starch and protein reserves, which did not prevent them, however, from germinating, and showing bipolar development. These somatic embryos further developed into young plants, similarly to zygotic embryos.
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Khoon, Gong; Eong, Ong
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The Matang Mangrove Forest Reserve in Malaysia has been managed for timber production since the beginning of the century and is reputedly the best managed mangrove forest in the world. The present management plan is a 30-year rotation period with two thinnings, at 15 and 20 years. However, there has been a decline in yield from 299 t ha−1 of green-wood from virgin stands to the second generation yields of 158 t ha−1 in 1967–69 to an even lower 136 t ha−1 in 1970–77.
This study on the demography of the forest was conducted to try to determine ways to improve the silviculture and management system. The species of the tree, whether it was living or dead, and the girth at breast height were recorded for all trees in selected representative plots covering a range of ages (5, 8, 13, 18, 23 and 28 years). The standing biomass of these plots was calculated using previously obtained allometric regressions.
The high density of 15 030 Rhizophora apiculata trees per hectare in the 5 year-old stand and the sharp decrease to 9810 in the 8 year-old stand indicate that the initial stocking was too high. We suggest that artificial regeneration should be carried out at 1.2 m intervals only if the natural regeneration is less than 50% (rather than 90% as is the present practice). Extremely high mortality occurred in the 13 year-old and the 18 year-old stands where 43% and 29% respectively of the Rhizophora trees were dead. We therefore suggest that the thinnings be carried out earlier — at 12/13 and 17/18 years (instead of 15 and 20 years) to reduce this wastage due to natural thinning. An additional silvicultural thinning could be carried out at 8–9 years to remove non-Rhizophora trees and to reduce stand density to around 8000 ha−1 to allow better growth. The standing biomass of the trees did not increase from 23 years (155 t ha−1) to 28 years (153 t ha−1). Based on biomass, we suggest that a rotation of 25 years be used instead of the present 30. This is also supported by size distribution of the stems which showed slow increase in the girth after 18 years.
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Wong, Ching-Lee; Gan, Sook-Yee; Phang, Siew-Moi
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Two Sargassum species (S. baccularia and S. polycystum) collected from Teluk Kemang and Cape Rachado, Port Dickson, Negeri Sembilan, Malaysia, which are alike in morphology except for the rhizoidal system and vesicles, were characterised using random amplified polymorphism DNA (RAPD). The genomic DNA of both species was isolated from the leaves using a modified CTAB method. Four random primers, that is, OPA2, OPA3, OPA4 and OPA13, successfully amplified the DNA. The polymorphisms generated by these four primers were analysed using the Dice Coefficient of Similarity and cluster analysis was carried out using GelCompar II Version 2.0 (Applied Maths, Kortrijk, Belgium) based on UPGMA. DNA analysis showed that three primers were able to differentiate the two species. Morphological analysis using Principal Components Analysis (PCA) and discriminant function analysis supported the molecular data. Both species are characterised by heavily muricate main branches, oblong-lanceolate leaves with dentate margins and discoid holdfasts and spherical vesicles; both are dioecious. The only difference is that S. polycystum has secondary holdfasts transformed into stolons. This last characteristic is therefore a very important criterion and may contribute to the difference shown by DNA analysis.
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Akmar, P. F.; Kennedy, J. F.
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The carbohydrates content of the water soluble and water insoluble material of the oil and sago palm trunk waste were analysed. The sago palm trunk waste yielded higher water soluble content (17.4%) compared to the parenchymatous tissues and fibers of the oil palm trunk waste i.e. 3.3% and 5.4%, respectively, with less than 10% of neutral carbohydrates detected by cysteine sulphuric assay. However, hot water solubles of the sago palm trunk contained about 61.7% glucose. On the other hand, the acid hydrolysable carbohydrates of the water insoluble materials of both oil and sago palm trunk waste were found to be less than 50% of the total materials. The fibers and parenchyma of the oil palm trunk yielded only 31.9% and 23.6% hydrolysable sugars, respectively. Glucose was the major monosaccharide afforded by all samples of oil and sago palm waste.
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Ng, Soon
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The13C NMR spectrum of the carbonyl carbons of the acyl groups of triacylglycerols of palm oil has been shown to give the composition of saturated, oleic and linoleic acyl groups at the 1,3-positions and at the 2-position of the glycerol moiety. Except for the lack of differentiation of the saturated fatty acids, the13C NMR technique provides the same information as the tedious enzymatic hydrolysis cum fatty acid analysis. The carbonyl carbon of the linolenic acyl group (18∶3,[cis, cis, cis]-9, 12, 15) has a chemical shift which is only 0.005 ppm to low frequency of that of the linoleic acyl group (18∶2,[cis, cis]-9, 12), so that the two resonances may not be distinguishable (or resolved) even at a high magnetic field.
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Balasubramaniam, Vimala; Mustar, Suraiami; Mustafa Khalid, Norhayati; Abd Rashed, Aswir; Mohd Noh, Mohd Fairulnizal; Wilcox, Matthew D.; Chater, Peter I.; Brownlee, Iain A.; Pearson, Jeffrey P.
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Ethanol extracts, dried powders and fibres (total and soluble fibre) of the tropical red algae Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum were analysed for their effect on lipase and α-amylase activity using turbidimetric method and dinitrosalicylic acid (DNS) assay, respectively. The nutrient composition analyses were determined using standard methods. The ethanol extract of dried K. striatus (Ks-III) showed the highest reduction in lipase activity with 92 % inhibition followed by seaweed powders (K. alvarezii (Ka-III), K. striatus (Ks-III) and E. denticulatum (Ed-III)) with average inhibition of 60 %. Soluble fibres of K. alvarezii (Ka-V) and E. denticulatum (Ed-V) showed significant inhibition with 60 and 57 % reduction, respectively. Only the ethanol extract of fresh E. denticulatum (Ed-I) showed 88 % inhibition of α-amylase. Nutritional component analyses showed that all three seaweeds are low in crude fat, suggesting the possible use of seaweed as a dietary supplement and for potential weight and glycaemia management.
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Ikram, A.; Mahmud, A. W.; Napi, D.
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The growth response ofCalopogonium caeruleum, a leguminous covercrop in plantation agriculture, to inoculation with two vesicular-arbuscular mycorrhizal (VAM) fungi was investigated in five phosphorus (P)-deficient soils supplied with various levels of rock phosphate. Significant shoot yield increases over the uninoculated controls were obtained in most sterilised or unsterilised soils at all applied P levels, although the inoculant VAM fungi differed in their effectiveness in the soils used. Responses in mycorrhizal root infections, P and nitrogen (N) concentrations in tops and plant nodulation varied. The results are discussed in relation to the edaphic environment of the mycorrhizal association.
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Alam, M. J.; Ang, K. J.; Begum, M.
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The effect of an abrupt change in the live diet of shrimp larvae was investigated by replacing Artemia with Moina micrura. The control treatment consisted of feeding Artemia throughout the rearing period (regime A), while in the other treatments the onset of Moina feeding was arbitrarily chosen at larval stages iv (A3M), vi (A5M), viii (A7M) and x (A9M). No significant differences (α = 0.05) were observed among the treatments during larval production, mean stage development (MSD) and growth of postlarvae. The mean (SD) yields of postlarvae (PL) were 11.97 (1.98), 15.10 (2.92), 14.72(1.56), 13.51 (1.74) and 12.70 (1.40) PL l−1 respectively for the feeding regimes A3M, A5M, A7M, A9M and A. Up to stage v, the ingestion rate in the Moina treatment was as low as 0.01–0.47 larva−1 h−1 compared with that in the Artemia treatment (0.29–1.77 larva−1 h−1). However, the ingestion of Moina increased from stage vi–vii onwards.
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Sai, Su Tiing; Keng, Chan Lai; Pargini, N.; Teo, Chris K. H.
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An in vitro culture system was developed for Typhonium flagelliforme using buds from the rhizomes. The mineral salts of four media were tested. These were Murashige and Skoog (MS), Nitsch and Nitsch (NN), Gamborg B5 (GB5) and White (W) of which MS medium was found to be the best medium for in vitro culture of T. flagelliforme. The addition of as low as 0.1 mg l−1 (0.54 μM) α-naphthalene acetic acid (NAA) with the presence or absence of N6-benzyladenine (BA) in the MS medium caused abnormal shoot formation. The best medium for maximizing shoot number combined with normal complete plantlets from each bud was MS medium supplemented with 0.3 mg l−1 (1.33 μM) BA and 0.5 mg l−1 (2.46 μM) indole-3-butyric acid (IBA). The best acclimatization process was to transfer the normal plantlets, with all the leaves removed, into sand plus coconut husks substrate (1∶1) and placed in intermittent water mists house or shaded plant house with 50% light exclusion. Ninety two percent of the plantlets survived using this acclimatization method.
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Cotton, Samuel; Small, Jennifer; Hashim, Rosli; Pomiankowski, Andrew
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Handicap models of sexual selection propose that females use male sexual ornaments as a cue in mate choice because they reflect commodities that increase female fitness, either directly or indirectly. In contrast to studies on vertebrates, most investigations of ornaments in insects and other invertebrate taxa have been conducted under laboratory conditions. There is a pressing need to address questions relating to sexual signalling of quality in natural populations, as the arbitrary and uniform environments found in the laboratory fail to reflect the world under which animals have evolved. We investigated associations between male ornaments (exaggerated eyespan), attractiveness, and reproductive quality in a wild population of the sexually ornamented stalk-eyed fly, Teleopsis dalmanni. We also explored the relationship between eyespan and reproductive quality in females to evaluate the potential for sexually antagonistic selection on eyespan. We show that eyespan is a generic correlate of reproductive quality, acting as a reliable mirror of variation in reproductive fitness in both sexes. Our findings suggest that male ornaments signal commodities that are of interest to females in the natural environment in which they, and mate preferences for them, have evolved. In addition, the covariance between female eyespan and reproductive output suggests that the former may be a reliable cue of quality in its own right. Our data provide important insights into the evolutionary forces that shape the evolution of exaggerated eyespan in wild populations of this species.
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Godoy, Ricardo A.; Feaw, Tan Ching
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Many developing countries are trying to promote agricultural diversification among smallholders because they feel that smallholders are too dependent upon a narrow range of crops. Fieldwork among smallholder rattan cultivators in Southern Borneo, Indonesia, suggests that smallholders do maintain a poorly diversified portfolio of agricultural activities. Farmers rely heavily upon rattan because of its superior profitability. A number of economic and agronimic constraints however prevent farmers from diversifying out of rattan into other crops.
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Shamekhi, Fatemeh; Shuhaimi, Mustafa; Ariff, Arbakariya; Manap, Yazid A.
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The purpose of this study was to improve the survival of Bifidobacterium animalis subsp. lactis 10140 during freeze-drying process by microencapsulation, using a special pediatric prebiotics mixture (galactooligosaccharides and fructooligosaccharides). Probiotic microorganisms were encapsulated with a coat combination of prebiotics–calcium-alginate prior to freeze-drying. Both encapsulated and free cells were then freeze-dried in their optimized combinations of skim milk and prebiotics. Response surface methodology (RSM) was used to produce a coating combination as well as drying medium with the highest cell viability during freeze-drying. The optimum encapsulation composition was found to be 2.1 % Na-alginate, 2.9 % prebiotic, and 21.7 % glycerol. Maximum survival predicted by the model was 81.2 %. No significant (p > 0.05) difference between the predicted and experimental values verified the adequacy of final reduced models. The protection ability of encapsulation was then examined over 120 days of storage at 4 and 25 °C and exposure to a sequential model of infantile GIT conditions including both gastric conditions (pH 3.0 and 4.0, 90 min, 37 °C) and intestinal conditions (pH 7.5, 5 h, 37 °C). Significantly improved cell viability showed that microencapsulation of B. lactis 10140 with the prebiotics was successful in producing a stable symbiotic powdery nutraceutical.
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Lim, Hong-Chang; Lim, Po-Teen; Su, Suriyanti Nyun-Pau; Teng, Sing-Tung; Leaw, Chui-Pin
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To clarify the genetic diversity of a potentially toxic pennate diatom, Pseudo-nitzschia brasiliana found in Malaysian waters, 30 strains of P. brasiliana were established into clonal culture since May 2008. The ultrastructure of these strains was examined for confirmation of species identification. The genetic marker, internal transcribed spacer (ITS) of nuclear-encoded ribosomal DNA was used to examine the genetic diversity of P. brasiliana isolated from different geographical localities. The ITS sequences of P. brasiliana were highly conserved in their secondary structures, with five helices in the first internal transcribe spacer (ITS1) and four universal helices in the second internal transcribe spacer (ITS2) with a pseudo-helix. No compensatory base change was observed among the strains examined. Genetic divergences among the Malaysian strains ranged from 0.07 to 0.54%. The present study revealed a high genetic homogeneity of Malaysian P. brasiliana strains.
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Livy, Alex; Lye, Sayhean; Jagdish, Chahil K.; Hanis, Nurul; Sharmila, Velapasamy; Ler, Lian Wee; Pramod, Bagali
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Buccal cell usage has been shown by many to be a cost effective and safe method to isolate DNA for various biological experiments especially large epidemiological studies (Garcia-Closas et al. Cancer Epidemiol Biomarkers Prev 10:687–696, 2001). Non-invasive DNA collection methods are preferred over phlebotomy in order to increase study participation and compliance in research centers and for sick patients in hospital settings. There have been conflicting reports about the methodology and results obtained from using buccal DNA. It is not very clear if phlebotomy can be confidently replaced by buccal cell DNA. It is often left for the user to take an intelligent decision. To address this issue, we compared the performance of buccal and blood DNA from same subjects in a genotyping experiment and this paper reports the results. Cotton swab derived buccal cells were scraped from the inner side of cheeks from 16 subjects, and blood was also drawn from the same 16 subjects participating in a genotypic association study of a lipid disease. The DNA quality was assessed by resolving on agarose gels, checking purity (A260/A280) and finally by microarray hybridization. This study showed that DNA degradation affects the total yield and performance of the buccal DNA when compared to the blood DNA in microarray based genotyping. Genotyping results can be seriously compromised if care is not taken to check the quality and yields of such specimens.
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Khor, K. E.; Chua, T. H.
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A rigorous mathematical model is formulated for describing population growth of the brown planthopper (Nilaparvata lugensStål, Homoptera), a major rice pest in Asia. The model is based on the assumption that the life history of a population can be approximated by breaking it into constant intervals corresponding to the natural stages of the insect's development. Starting with the balance equation ofvon Foerster
$$\frac{{\partial f(a,t)}}{{\partial t}} + \frac{{\partial f(a,t)}}{{\partial a}} + \partial (a,t)f(a,t) = 0,$$
We derived a set of differential equations for the model. The model incorporates density effects on the proportion of macropterous adults and on the nymphal survival rate. The basic biological data used in the model was taken from Japanese sources. The simulation results of the model agree with the main features of Japanese field data. For example, the predicted adult populations for the three generations in a rice crop are 0.16, 1.69 and 3.09 compared to the field data of 0.16, 1.38 and 5.40. Sensitivity experiments have also been carried out to show (i) the effect of the initial immigrant population and (ii) the relative importance of biological vital rates such as fecundity, egg survival rate, nymphal survival rate and adult death rate.
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Taha, Ekhlass M.; Omar, Othman; Yusoff, Wan Mohtar Wan; Hamid, Aidil Abdul
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Lipid biosynthesis and fatty acids composition of oleaginous zygomycetes, namely Cunninghamella bainieri 2A1, cultured in media with excess or limited nitrogen were quantitatively determined at different times of culture growth. Accumulation of lipids occurred even when the activity of NAD+-ICDH (β-Nicotinamide adenine dinucleotide-isocitrate dehydrogenase) was still detectable in both media. In C. bainieri 2A1, under nitrogen limitation, the ratio of lipids was around 35%, whereas in nitrogen excess medium (feeding media supplemented with ammonium tartarate), the lipid ratio decreased. The amount of this decrease depended on the level of ammonium tartarate in the media. The main findings in this paper were that C. bainieri 2A1 has the ability to accumulate lipid although nitrogen concentration detected inside the media and that NAD-ICDH was active in all culture periods. These results proved that the strain C. bainieri 2A1 has an alternative behavior in lipid biosynthesis that differs from yeast. According to the old hypotheses, yeasts could not accumulate lipid more than 10% when nitrogen was detected inside the media. Nitrogen-limited and excess media both contained the same fatty acids (palmitic acid, stearic acid, olic acid, linoleic acid and γ-linolenic acid), but at different concentrations. The C:N ratio was also studied and showed no effects on total lipid accumulation, but a significant effect on γ-linolenic acid concentration.
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Hong, Tan Keng; Jaal, Zairi
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The populations of native male adult oriental fruit flyDacus dorsalis (Hendel) and artocarpus fruit flyD. umbrosus (F.) in two selected site (BU and SD) were estimated weekly by the capture-recapture technique using live traps baited with methyl eugenol. In BU where many varieties of fruit trees were grown, the estimated population densities ofD. dorsalis were between 980 and 3100 male flies per ha between May and July, 1984. During the same period, in SD where there were fewer number and varieties of fruit trees, the estimated population densities were between 300 and 1000 flies per ha. The estimated population densities ofD. umbrosus over the same period were between 570 and 1290 flies per ha in BU; and between 5 and 95 flies per ha in SD.
Of a total 6828 markedD. dorsalis flies released only one fly (released 6 weeks earlier in BU) was caught in a different site.
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Bolle-Jones, E. W.; Notton, B. A.
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1. Potato plants were grown in pot sand cultures at different levels of iron and potassium supply. Plants grown at the lowest level of iron developed iron deficiency chlorosis and potassium deficiency symptoms when maintained at the lowest level of potassium but not at the highest level.
2. Rapid procedures were developed for the extraction and estimation of chloroplast pigments from small samples of lamina—usually less than 1 g of fresh material.
3. The expression of pigment content on an area basis gave results which were in better agreement with visual observations than those expressed on either fresh or dry weight basis.
4. Both iron and potassium additions increased the chloroplast pigment content. Leaves exhibiting iron deficiency contained reduced quantities of all pigments per unit area of lamina.
5. A linear relationship existed between chlorophyll and carotene, chlorophyll and xanthophyll, and carotene and xanthophyll contents.
6. The results suggested that laminae completely deficient in chlorophyll would contain no carotene but might still contain xanthophyll.
7. The relative proportions of chlorophyll, carotene and xanthophyll do not remain constant under varying conditions of iron status. When iron is deficient the proportion of xanthophyll increased in relation to the chlorophyll and carotene contents.
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Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan
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The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.
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Yap, C. K.; Ismail, A.; Tan, S. G.; Omar, H.
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Ecotoxicological tests were conducted in the green-lipped mussel Perna viridis under laboratory conditions. Different rates of accumulation and depuration in soft tissues are found and this might be due to different mechanisms of metal binding and regulation. At the end of depuration, Cd levels in soft tissues of P. viridis were 10–30 times higher than before exposure, while Zn levels in soft tissues were almost similar to levels before exposure. These results indicate that P. viridis is a good biomonitoring organism for Cd but Zn levels might be actively regulated. It remains uncertain whether P. viridis is a good biomonitoring organism of environmental Zn contamination. However, the positive patterns, although different rates, of accumulation and depuration for Cd and Zn support the use of P. viridis as a biomonitoring agent for such metals.
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Chee, Swee-Yong; Wong, Ping-Keong; Wong, Ching-Lee
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Four species of brown seaweeds, namely Sargassum baccularia, Sargassum binderi, Sargassum siliquosum and Turbinaria conoides, harvested from Port Dickson, Negeri Sembilan, Malaysia were analysed for ash content, alginate yield and alginate properties. Seaweeds calcined at 450°C were found to have low amount of non-combustible residue as these were not contaminated by calcareous animals. Alginate was extracted from these seaweeds by two methods: hot and cold. In the hot method, the storing time was 3 h and the processing temperature was 50°C, whilst in the cold method, the sample was stored overnight at room temperature. Higher yield of alginate was obtained by the hot method compared to the cold method, but alginate extracted by the cold method gave higher molecular weight. In the hot method, 49.9% of alginate was extracted from S. siliquosum, followed by T. conoides (41.4%), S. binderi (38.9%) and S. baccularia (26.7%). Alginate extracted from T. conoides has an average molecular weight, Mw, of 8.06 × 105 g mol−1, whereas alginate from S. siliquosum was the lowest in Mw (4.81 × 105 g mol−1) when the extraction was done at room temperature. Alginate extracted from S. baccularia was found to be very heat-sensitive. Its Mw has dropped more than 83%, from 7.52 × 105 to 1.23 × 105 g mol−1, when the extraction temperature was raised. The effect of heat on the extent of depolymerisation of the alginate molecule of the other three brown seaweed species was less significant, with decrease in molecular weight ranging between 13% and 16%.
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Ahmad, Rohani; Chu, Wan-Loy; Lee, Han-Lim; Phang, Siew-Moi
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The effect of four microalgal chlorophytes, Chlorella vulgaris,Scenedesmus quadricauda, Chlorococcum sp. and Ankistrodesmus convolutus, on the survival, larval development and adultbody size of the mosquito Aedes aegypti was investigated. The percentage mortality of larvae fed with C. vulgaris, Chlorococcum sp.or S. quadricauda after six days was 100%, 84% and 88%,respectively. Delayed pupation and body size reduction of the mosquitoesfed with C. vulgaris, Chlorococcum sp. and S. quadricaudawere observed. In contrast, larvae fed with A. convolutus werebigger than those fed with normal insectory feed. The study showed thatC. vulgaris, S. quadricauda and Chlorococcum sp. have potentialto be used as larvicidal agents.
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Prakash, V.
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Multiple-point crosses where 20 pairs of regions (ten loosely linked markers) for the study of contiguous exchanges involving two linkage groups, capable of being investigated at a time, were utilized. In order to find out the effect of a chelating agent on interference, crosses were treated with different molar concentrations of ethylene-diamine tetraacetic acid (EDTA). All marker strains were standardized before use by inbreeding with a wild-type of known parentage.
Since tests based on Coefficient of Coincidence and on Poisson distribution for finding out the position interference are rather unsatisfactory, a method based onContingency Chi-square test for detecting the intensity and nature of interference is described.
Data obtained from 1813 analyzable ordered tetrads show that positive interference is absent in the control crosses. It is present among certain regions in crosses when treated with 4×10−5M and 10×10−5M EDTA but it vanishes again in crosses when treated with 20×10−5M EDTA. Negative interference is present in the control crosses but it varies among pairs of regions on the two linkage groups. The localization and intensity of interference are alterable with EDTA treatment. The data are discussed in the light of certain concepts invoking to explain the mechanism that involves a genetic exchange.
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Tatt, Ong Hean
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Sucrose gradient analyses were made on free ribosomes extracted from Azuki bean seedling leaves subjected to mannitol induced water stress. Comparisons were made of the effect of duration of stress and the effect of urea on the free ribosomes. The capacities of the ribosomal fractions to incorporate amino-acids were also studied. Water stress reduced total free ribosomes and proportion of polysomes in the ribosomes as well as the capacity of the ribosomes to incorporate amino-acids into proteins. Polysomes which were broken down by the water stress also appeared to be more susceptible to denaturation and synthesized different proteins than polysomes which remained in the leaves after water stress.
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Yong, Seok Yien Christina; Wickneswari, Ratnam
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Cellulose is the major component of plant cell walls, providing mechanical strength to the structural framework of plants. In association with lignin, hemicellulose, protein and pectin, cellulose forms the strong yet flexible bio-composite tissue of wood. Wood formation is an essential biological process and is of significant importance to the cellulosic private sector industry. Cellulose synthase genes encode the catalytic subunits of a large protein complex responsible for the biogenesis of cellulose in higher plants. The hybrid Acacia auriculiformis x Acacia mangium represents an important source of tree cellulose for forest-based product manufacturing, with enormous economic potential. In this work, we isolate the first cellulose synthase gene, designated AaxmCesA1, from this species. The isolated full-length AaxmCesA1 cDNA encodes a polypeptide of 1,064 amino acids. Sequence analyses revealed that AaxmCesA1 cDNA possesses the key motif characteristics of a CesA protein. AaxmCesA1 shares more than 75 % amino acid sequence identity with CesA proteins from other plant species. Subsequently, the full-length AaxmCesA1 gene of 7,389 bp with partial regulatory and 13 intron regions was also isolated. Relative gene expression analysis by quantitative PCR in different tissues of the Acacia hybrid, suggests the involvement of the AaxmCesA1 gene in primary cell wall synthesis of rapidly dividing young root cells. Similarity analyses using Blast algorithms also suggests a role in primary cell wall deposition in the Acacia hybrid. Southern analysis predicts that AaxmCesA1 is a member of a multigene family with at least two isoforms in the genome of the Acacia hybrid.
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Nudin, Nur Fatihah Hasan; S., Siddiquee
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The taxonomy of the causal pathogen of basal stem rot of oil palms, Ganoderma is somewhat problematic at present. In order to determine the genetic distance relationship between G. boninense isolates and non-boninense isolates, a random amplified microsatellites DNA (RAMS) technique was carried out. The result was then compared with interfertility data of G. boninense that had been determined in previous mating studies to confirm the species of G. boninense. Dendrogram from cluster analysis based on UPGMA of RAMS data showed that two major clusters, I and II which separated at a genetic distance of 0.7935 were generated. Cluster I consisted of all the biological species G. boninense isolates namely CNLB, GSDK 3, PER 71, WD 814, GBL 3, GBL 6, OC, GH 02, 170 SL and 348781 while all non-boninense isolates namely G. ASAM, WRR, TFRI 129, G. RES, GJ, and CNLM were grouped together in cluster II. Although the RAMS markers showed polymorphisms in all the isolates tested, the results obtained were in agreement with the interfertility data. Therefore, the RAMS data could support the interfertility data for the identification of Ganoderma isolates.
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Chong, Geeng-Loo; Chu, Wan-Loy; Othman, Rofina Yasmin; Phang, Siew-Moi
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Changes in gene expression are an important response of Antarctic algae to temperature stress. The objective of this study was to investigate the differential gene expression of the Antarctic alga Chlorella UMACC 234 in response to temperature stress. The RNA was extracted from the cells grown at 4, 20, and 30°C and converted to cDNA by reverse transcription. Differentially expressed genes (DEG) were isolated and identified using the GeneFishing™ DEG Kit (Seegene) with 20 arbitrary annealing control primers (ACP). The bands of interest were excised and purified from the agarose gel and then cloned and sequenced. A total of 22 DEG clones were isolated and identified, with 11 DEG detected only at 30°C and six DEG detected only at 4°C. Three DEG were detected at 4 and 20°C while two were detected at 20 and 30°C. The DEG were associated with functions such as photosynthesis, carbohydrate metabolism, electron transfer, and cell maintenance. Three DEG that showed high degree of similarity with sequences from the database were those code for Photosystem II P680 chlorophyll a apoprotein CP47 (PSII-CP47), aldose 1-epimerase, and a putative oxidoreductase. Real-time PCR analysis showed that the expression of the PSII-CP47 gene increased by threefold at 4°C while that of the aldose 1-epimerase and oxidoreductase genes increased by threefold and eightfold, respectively, at 30°C compared with 20°C (optimal growth temperature).
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Nakamura, Mitsuo; Seikai, Tadahisa; Aritaki, Masato; Masuda, Reiji; Tanaka, Masaru; Tagawa, Masatomo
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Flatfishes display a left–right asymmetry that is unique in the animal kingdom. In order to clarify the mechanisms of the asymmetrical development of pigment cells, changes in pigment cell densities were examined in Japanese flounder Paralichthys olivaceus. During development from symmetrical larvae to asymmetrical juveniles, pigment cell densities were monitored on the skin on both the left side (ocular side in juvenile; eventually has two eyes) and the right side (blind side in juvenile; eventually has no eyes). A symmetrical and constant decrease was observed in leucophores and larval type melanophores. A mostly symmetrical (slightly delayed on the blind side) and constant increase in iridophores from metamorphosis was observed. Adult-type melanophores appeared and then increased only after metamorphosis on the ocular side. However, the pattern of xanthophores was complicated: they first existed symmetrically and decreased symmetrically until metamorphosis, and they later increased only on the ocular side. The dual appearance of the xanthophores, as well as the differences between their depths and sizes on the ocular and blind sides, may suggest the presence of two types of xanthophores—just as melanophores are well known to exhibit two types. The ontogenetic study of pigment cells described here is likely to help to elucidate the process of abnormal pigmentation in flatfishes.
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Low, Eng-Ti; Alias, Halimah; Boon, Soo-Heong; Shariff, Elyana; Tan, Chi-Yee; Ooi, Leslie; Cheah, Suan-Choo; Raha, Abdul-Rahim; Wan, Kiew-Lian; Singh, Rajinder
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Background
Oil palm ( Elaeis guineensis Jacq.) is one of the most important oil bearing crops in the world. However, genetic improvement of oil palm through conventional breeding is extremely slow and costly, as the breeding cycle can take up to 10 years. This has brought about interest in vegetative propagation of oil palm. Since the introduction of oil palm tissue culture in the 1970s, clonal propagation has proven to be useful, not only in producing uniform planting materials, but also in the development of the genetic engineering programme. Despite considerable progress in improving the tissue culture techniques, the callusing and embryogenesis rates from proliferating callus cultures remain very low. Thus, understanding the gene diversity and expression profiles in oil palm tissue culture is critical in increasing the efficiency of these processes.
Results
A total of 12 standard cDNA libraries, representing three main developmental stages in oil palm tissue culture, were generated in this study. Random sequencing of clones from these cDNA libraries generated 17,599 expressed sequence tags (ESTs). The ESTs were analysed, annotated and assembled to generate 9,584 putative unigenes distributed in 3,268 consensi and 6,316 singletons. These unigenes were assigned putative functions based on similarity and gene ontology annotations. Cluster analysis, which surveyed the relatedness of each library based on the abundance of ESTs in each consensus, revealed that lipid transfer proteins were highly expressed in embryogenic tissues. A glutathione S-transferase was found to be highly expressed in non-embryogenic callus. Further analysis of the unigenes identified 648 non-redundant simple sequence repeats and 211 putative full-length open reading frames.
Conclusion
This study has provided an overview of genes expressed during oil palm tissue culture. Candidate genes with expression that are modulated during tissue culture were identified. However, in order to confirm whether these genes are suitable as early markers for embryogenesis, the genes need to be tested on earlier stages of tissue culture and a wider range of genotypes. This collection of ESTs is an important resource for genetic and genome analyses of the oil palm, particularly during tissue culture development.
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Saamin, S.; Thompson, M. M.
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Dormant scions of ‘Bing’ were exposed to 1–2.5 krad of gamma radiation in order to induce useful mutations. The main buds were excised and the scions grafted to allow the growth of accessory buds into primary (V1) shoots. The frequency and types of mutations on secondary (V2) populations are described. In a population of 3324 V2 shoots, the overall mutation frequency was 6.4%: 4.2% partial, 1.6% total and 0.3% growth-reduced mutants were identified. The experiment was repeated using 3 krad- and 4 krad-fractionated doses in water. Differences in mutation frequency at 3 krad and 4 krad were not significant. Of 2562 surviving V2 shoots derived from the irradiation of accessory buds of both standard and V1 shoots, the overall mutation frequency was 3.3%: 1.7% were partial-leaf mutants, 1.0% were total-leaf mutants, and 0.54% were growth-reduced mutants. For maximum mutation rate with adequate survival we suggest acute irradiation of accessory buds in air at dosages approximating LD50 (2.75–3 krad). A larger mutant sector was present in V1 shoots derived from accessory buds than those from main buds as revealed by the higher number of total mutant repeats in the families.
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Chong, C. W.; Convey, P.; Pearce, D. A.; Tan, I. K. P.
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Despite an increasing number of Antarctic soil diversity assessments, understanding of the bacterial community composition in the arid soil environments of the maritime/continental Antarctic transitional zone remains lacking. Most documented microbiological studies had focused on either the wetter environments of the Antarctic Peninsula/Scotia arc or the exceptionally arid deserts of the Dry Valleys of continental Antarctica. In this study, soil bacterial diversity from three relatively arid sites on Alexander Island and the physicochemical parameters that might influence it were assessed. In general, the study sites exhibited levels of pH, hydration and metal content different from previous reports of maritime or continental Antarctic soil habitats. Although the soil from Alexander Island exhibited similar phylum-level bacterial taxonomic composition to those of other cold and arid environments, each study site was found to harbour significantly different bacterial assemblages. The latter finding was supported by three complementary molecular methods selected to address different elements of diversity. Our analyses of the measured parameters suggest that the differences in bacterial communities were best explained by soil pH and copper content. Using these data, we suggest that soil pH might play an important role in structuring bacterial assemblage patterns across polar soils.
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Ratnasingam, J.; Scholz, F.; Natthondan, V.
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The study evaluated airborne dust emission (0.1–10 µm) during the routing operation
of Rubberwood (Hevea brasiliensis) in the furniture industry in South
East Asia. It was found that the average chip thickness of 0.1 mm and wood moisture content of 12–14%
minimized dust emission, while the cutting tool rake angle had little influence on dust emission. The study
shows that adverse economic implications due to health hazards posed by airborne dust emissions during wood
machining can be reduced by manipulating the average chip thickness and work-piece moisture content.
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Garrity, D. P.; Soekardi, M.; Noordwijk, M.; Cruz, R.; Pathak, P. S.; Gunasena, H. P. M.; So, N.; Huijun, G.; Majid, N. M.
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The rehabilitation or intensified use of Imperata grasslands will require a much better understanding of their area, distribution, and characteristics. We generated estimates of the area of Imperata grasslands in tropical Asia, and suggested a typology of Imperata grasslands that may be useful to define the pathways toward appropriate land use intensification. We conclude that the area of Imperata grasslands in Asia is about 35 million ha. This about 4% of the total land area. The countries with the largest area of Imperata grasslands are Indonesia (8.5 million ha) and India (8.0 million ha). Those with the largest proportion of their surface area covered with Imperata are Sri Lanka (23%), the Philippines (17%), and Vietnam (9%). Laos, Thailand, Myanmar, and Bangladesh evidently all have similar proportions of their land area infested with Imperata (about 3 to 4%). Malaysia (< 1%), Cambodia (1%), and the southern part of China (2%) have but a minor proportion of their total land area in Imperata. The species was found widely distributed on the full range of soil orders. It occupied both fertile (e.g. some of the Inceptisols and Andisols) and infertile soils (Ultisols and Oxisols) across a wide range of climates and elevations. Imperata lands fall into four mapping scale-related categories: Mega-grasslands, itmacro-grasslands, meso-grasslands, and micro-grasslands. The mega-grasslands are often referred to as ‘sheet Imperata’. They are the large contiguous areas of Imperata that would appear on small-scale maps of say 1:1,000,000. We propose that this basic typology be supplemented with a number of additional components that have a key influence on intensification pathways: land quality, market access, and the source of power for tillage. The typology was applied in a case study of Indonesian villages in the vicinity of Imperata grasslands. We propose an international initiative to map and derive a more complete and uniform picture of the area of the Imperata grasslands. This should include selected studies to understand conditions at the local level. These are critical to build the appreciation of change agents for the indigenous systems of resource exploitation, and how they relate to local needs, values and constraints.
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Jin-Eong, Ong
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Despite the recent better understanding and awareness of the role of mangroves, these coastal forest communities continue to be destroyed or degraded (or euphemistically reclaimed) at an alarming rate. The figure of 1% per year given by Ong (1982) for Malaysia can be taken as a conservative estimate of destruction of mangroves in the Asia-Pacific region. Whilst the Japanese-based mangrove wood-chips industry continues in its destructive path through the larger mangrove ecosystems of the region, the focus of mangrove destruction has shifted to the conversion of mangrove areas into aquaculture ponds and the consequences of the unprecedented massive addition of carbon dioxide to the atmosphere by post industrial man.
Mangroves are non-homogeneous; characterised by distinct vegetative zones that occupy the interface between land and sea and dynamically interacting with the atmosphere above as well as with the influences of the adjacent land and sea. The conservation of mangroves should thus include not only the various vegetation and tidal inundation zones but also the adjacent marine and terrestrial areas (including the water catchment area).
On the current concern with global climate change, it is pointed out that relative sea level change is very much site dependent. For effective planning and management, it is vital to know if a particular site is stable, rising or sinking so efforts should be directed to find suitable methods for determining this. However, should rapid relative sea level rise take place, there is very little likelihood of saving mangroves whose landward margins have been developed by man, a fact to bear in mind when selecting sites for conservation. The Matang mangroves of Malaysia is rare case of successful sustainable management of a tropical rain forest. Although the tools of management are available they are not widely applied. We particularly urge the Japanese mangrove wood-chips industry to look to long term sustainable use rather than short term gains. A suggestion is made to appeal to the new Government of Japan to take the lead in environmental friendliness especially to the rain forests of the Asia-Pacific region.
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Wickneswari, Ratnam
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The major threat to genetic viability of the Southeast Asian forest species is commercial logging and fragmentation being largely due to infrastructural development and agricultural activities. Species vulnerability to the threat of genetic viability posed by commercial logging is highly correlated with its abundance in a particular forest management unit. Tree density for the species can be a useful indicator in reflecting the risk of genetic viability rather than the overall disturbance level based on reduction in basal area of all trees. Reproductive success of mature trees together with successful regeneration of seedlings and saplings in disturbed forests is an important determinant of genetic viability of species. Knowledge of the biological attributes of species including their local evolution can be used to develop field guides in harvesting operations to ensure the genetic quality of residuals left behind in the post-harvest stands.
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Beulé, Thierry; Camps, Céline; Debiesse, Ségolène; Tranchant, Christine; Dussert, Stéphane; Sabau, Xavier; Jaligot, Estelle; Alwee, Sharifah Shahrul Rabiah Syed; Tregear, James W.
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Micropropagation of oil palm by somatic embryogenesis produces a proportion of off-type individuals (approximately 5% overall) displaying a homeotically modified flower structure known as mantled. Transformation of the fertile or sterile androecium into carpel-like structures is observed in staminate and pistillate mantled flowers, respectively, resulting in lower oil yields in affected plantations. Given the epigenetic nature of the mantled condition, a gene expression-based approach was used rather than a genetic one to investigate its molecular basis. Suppression subtractive hybridisation (SSH) and macroarray hybridisation were used to compare transcriptome patterns between normal and mantled inflorescences. Two SSH libraries, enriched for complementary deoxyribonucleic acids (cDNAs) of either true-to-type or somaclonal variant material, were generated. Bioinformatic analysis of these two libraries allowed the identification of 1,350 unique sequences and their annotation by a gene ontology-based approach. Macroarray hybridisation was used to compare gene expression between normal and mantled inflorescences, and 32 genes were found to be differentially expressed. The temporal expression patterns of six genes were further investigated in more detail in relation to male and female inflorescence development. Full-length cDNAs were isolated and characterised for two of these genes, EgFB1 and EgRING1, both of which are down-regulated in the mantled inflorescences and both of which encode proteins associated with proteolytic signalling complexes. Our data shed light on gene expression changes associated with the mantled phenotype and have provided novel transcriptome markers which can help to distinguish the abnormal and wild-type inflorescences.
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Lim, L. H. S.; Gibson, D. I.
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Two known and two new species of Diplectanocotyla Yamaguti, 1953 (D. gracilis Yamaguti, 1953, D. megalopis Rakotofiringa & Oliver, 1987, D. langkawiensis n. sp. and D. parva n. sp.) were collected from Megalops cyprinoides (Megalopidae) off Langkawi, Kedah and Matang, Perak, Peninsular Malaysia. All four species possess similar types of sclerotised male and female reproductive structures and similar soft anatomical features. The squamodisc sclerites of all four species have spine-like projections with varying degrees of visibility and shapes (sharp-pointed to triangular). In D. megalopis and D. langkawiensis n. sp. the spines are sharp-pointed and distinct on sclerites from rows 5–6 onwards. In D. gracilis and D. parva n. sp. the sclerite spines are triangular, lightly sclerotised and occur on almost all of the sclerites. D. parva n. sp. has comparatively the smallest set of anchors, bars, squamodiscs and squamodisc suckers. The anchors and bars of the other three species are almost similar in overall size, and the main distinguishing feature is the relative lengths of the inner and outer roots of the ventral anchors. In D. gracilis the outer root is very much smaller than the inner root and they are disposed almost at a right angle to each other. In D. megalopis the outer root is usually about half the length of the inner root and the roots are inclined at c.60° to each other. In D. langkawiensis n. sp. the roots are inclined at c.40° degrees and the outer root is of a similar length or only slightly shorter than the inner root. The openings of the two squamodisc suckers of all four Diplectanocotyla species are surrounded by tiny scale-like spines. Bifid tegumental spines are found in the posterior region of all four species, differing only in their extent: in D. parva n. sp. the tegumental spines are only distributed in the peduncular region and not beyond, whilst in the other three species the tegumental spines extend from the posterior level of the testis to the end of the peduncle. An amended diagnosis of Diplectanocotyla and a key to its species are appended.
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Unelius, C. R.; Park, K.-C.; McNeill, M.; Wee, S. L.; Bohman, B.; Suckling, D. M.
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An investigation to identify a sex or aggregation pheromone of Sitona discoideus Gyllenhål (Coleoptera: Curculionidae) is presented. Antenna flicking and attraction behaviors evoked by conspecifics of both sexes were recorded in arena bioassays, where attraction of females to males was observed. Air entrainment of both males and females was conducted in separate chambers. Gas chromatographic–mass spectrometric analysis of headspace volatiles revealed that two male-specific compounds, 4-methyl-3,5-heptanedione (major) and (4S,5S)-5-hydroxy-4-methyl-3-heptanone (minor), were emitted during the autumnal post-aestivatory flight period. The stereoisomers of the minor component were separated by enantioselective gas chromatography and their absolute configurations assigned by NMR (diastereomers) and the known preference of enantioselective transesterification reactions catalyzed by Candida antarctica lipase B. Electroantennogram and single sensillum recording studies indicate that 4-methyl-3,5-heptanedione as well as all individual stereoisomers of 5-hydroxy-4-methyl-3-heptanone are detected by the antennae of male and female S. discoideus. Further, single sensillum recordings suggest that both sexes of S. discoideus have specialized olfactory receptor neurons (ORNs) for detecting 4-methyl-3,5-heptanedione and different populations of stereoselective ORNs for detecting the stereoisomers of 5-hydroxy-4-methyl-3-heptanone. Some of these stereoselective ORNs appear to be sex-specific in S. discoideus.
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Yamada, Toshihiro; Tan, Sylvester; Yamakura, Takuo
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We compared aboveground tree forms among closely related species in two genera of the Sterculiaceae (Scaphium and Heritiera) in a Bornean mixed dipterocarp forest. Two significant allometric patterns were detected: a negative correlation between the height at the onset of branching and the slope of the species-specific Cr (crown width)-D (stem diameter) allometric relationship for juveniles (D<10 cm), and a negative correlation between Hmax (observed maximum height) and the Cr-D slope. The slope of the Cr-D allometric relationship of branched trees was significantly steeper than that of monoaxial (unbranched) trees in most species. These results suggest that the branching growth habit is better adapted than the monoaxial growth habit to crown expansion, and that the morphology of short species is better adapted to crown expansion than that of tall species. We did not detected significant correlations between the height at the onset of branching and the slope of the H (height)-D allometric relationship for juvenile trees, and between Hmax and the H-D slope. In addition, the monoaxial and branched juvenile of most species did not differ significantly in the allometric slopes of the H-D relationship. Therefore, the study does not support the hypotheses that a monoaxial growth habit favors rapid height growth and that tall species have allometries better adapted to height growth.
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Rahman, Raja; Leow, Thean; Salleh, Abu; Basri, Mahiran
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Background
Thermophilic Bacillus strains of phylogenetic Bacillus rRNA group 5 were described as a new genus Geobacillus . Their geographical distribution included oilfields, hay compost, hydrothermal vent or soils. The members from the genus Geobacillus have a growth temperatures ranging from 35 to 78°C and contained iso-branched saturated fatty acids (iso-15:0, iso-16:0 and iso-17:0) as the major fatty acids. The members of Geobacillus have similarity in their 16S rRNA gene sequences (96.5–99.2%). Thermophiles harboring intrinsically stable enzymes are suitable for industrial applications. The quest for intrinsically thermostable lipases from thermophiles is a prominent task due to the laborious processes via genetic modification.
Results
Twenty-nine putative lipase producers were screened and isolated from palm oil mill effluent in Malaysia. Of these, isolate T1 T was chosen for further study as relatively higher lipase activity was detected quantitatively. The crude T1 lipase showed high optimum temperature of 70°C and was also stable up to 60°C without significant loss of crude enzyme activity. Strain T1 T was a Gram-positive, rod-shaped, endospore forming bacterium. On the basic of 16S rDNA analysis, strain T1 T was shown to belong to the Bacillus rRNA group 5 related to Geobacillus thermoleovorans (DSM 5366 T ) and Geobacillus kaustophilus (DSM 7263 T ). Chemotaxonomic data of cellular fatty acids supported the affiliation of strain T1 T to the genus Geobacillus . The results of physiological and biochemical tests, DNA/DNA hybridization, RiboPrint analysis, the length of lipase gene and protein pattern allowed genotypic and phenotypic differentiation of strain T1 T from its validly published closest phylogenetic neighbors. Strain T1 T therefore represents a novel species, for which the name Geobacillus zalihae sp. nov. is proposed, with the type strain T1 T (=DSM 18318 T ; NBRC 101842 T ).
Conclusion
Strain T1 T was able to secrete extracellular thermostable lipase into culture medium. The strain T1 T was identified as Geobacillus zalihae T1 T as it differs from its type strains Geobacillus kaustophilus (DSM 7263 T ) and Geobacillus thermoleovorans (DSM 5366 T ) on some physiological studies, cellular fatty acids composition, RiboPrint analysis, length of lipase gene and protein profile.
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Islam, Md. Shahidul; Yamashita, Yoh; Tanaka, Masaru
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Recruitment in marine fishes is regulated largely by the demographic changes that occur during the early life stages; therefore, a thorough understanding of early life stages is essential for predicting recruitment variability in fishes. Japanese sea bass (JSB), Lateolabrax japonicus, is a coastal marine fish distributed in East Asian coastal waters, and is regarded as highly important for commercial and recreational fisheries, for marine and brackish water aquaculture as well as for stock enhancement. JSB is a typical estuarine dependent temperate fish, which spawns in shelf areas and coastal embayments and the larvae and juveniles are dispersed and transported into shallow nearshore habitats and estuaries where they spend the early life. In this paper, we provide insight into the early life history and ecology of JSB through a revision of the available information and using the data we obtained from a relatively long-term research. We review and discuss the distribution and habitat use, food and feeding, age and growth, mortality and recruitment of larval and juvenile JSB in coastal waters around Japan. We extend our discussions in all available dimensions: habitat-specific, ontogenetic, and spatio-temporal, and highlight the importance of nursery habitats. We also discuss the implications of early life history for recruitment of JSB as well as the possible effects of climate change. At the end, we point out potential areas for future research.
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Jones, E. B. Gareth; Pang, Ka-Lai
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This paper reports on the distribution of fungal communities in aquatic habitats in tropical regions and highlights differences in the taxa observed in freshwater and marine habitats. Ascomycetes are dominant on substrata in marine environments, with few basidiomycetes and discomycetes. Equally, few freshwater basidiomycetes and discomycetes have been reported from the tropics. In marine habitats, Dothideomycetes dominate on mangrove substrata, and halosphaeriaceous species are most numerous on submerged woody substrata in coastal waters, while yeasts are common in seawater and estuarine habitats. In freshwater, Ingoldian anamorphic fungi are most numerous on decaying leaves, while ascomycetes (Dothideomycetes, Sordariomycetes) are prevalent on submerged/exposed woody substrata. Unique fungi are found in tropical waters and differ from those in temperate locations.
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Ng, K.P.; Soo-Hoo, T.S.; Na, S.L.; Ang, L.S.
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A total of 576 dermatophytes were isolated from patients with a variety of skin infections from January 1993 to May 2000. Ten species of dermatophytes were identified: Epidermophyton floccosum (0.7%), Microsporum audouinii (1.1%), M. canis (3.1%), M. gypseum (0.3%), Trichophyton concentricum(3.5%), T. equinum (0.2%), T. mentagrophytes (36.%), T . rubrum (53.8%), T. verrucosum (0.2) and T. violaceum (1.0%). The body sites most frequently affected by dermatophytes were the buttocks, nails and trunk. Anthropophilic dermatophytes made up 60.1% of the isolates; the most common species was T. rubrum, T. mentagrophytes and M. canis were the two main zoophilic dermatophytes. T. mentagrophytes was isolated from all body sites except the scalp. M. canis was found to be associated with domestic dogs and wasnot isolated from ethnic Malays. The only geophilic dermatophyte was M. gypseum, an uncommon dermatophyte associated with tinea pedis.
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Norhayati, M.; Noor, S. Mohd; Chong, K.; Faizah, A. W.; Herridge, D. F.; Peoples, M. B.; Bergersen, F. J.
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Methods for partitioning the nitrogen assimilated by nodulated legumes, between nitrogen derived from soil sources and from N2 fixation, are described as applied in peninsular Malaysia.
The analysis of nitrogenous components translocated from the roots to the shoots of nodulated plants in the xylem sap is outlined, with some precautions to be observed for applications in the tropics. Some examples of the use of the technique in surverying apparent N2 fixation by tropical legumes, in studying interrow cropping in plantation systems and in assessing effects of experimental treatments on N2 fixation by food legumes, are described.
Techniques for assesing N2 fixation by means of15N abundance have been used to show that applications of nitrogenous fertilizers commonly used in Malaysia for soybeans depress N2 fixation, that similar results are obtained with natural abundance and15N-enrichment methods and that, in at least two locations in Malaysia, differences between the natural abundance of15N in plant-available soil nitrogen and in atmospheric N2 are great enough to permit application to measurement of N2 fixation by leguminous crops.
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Siow, Rouh-San; Teoh, Seddon; Teo, Swee-Sen; Abd. Shukor, Mohd. Yunus; Phang, Siew-Moi; Ho, Chai-Ling
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GDP-mannose-3′,5′-epimerase (GME) is an enzyme involved in the biosynthesis of GDP-l-galactose which is a building unit of agar and cell wall polysaccharides. GME catalyzes the formation of GDP-β-l-galactose and GDP-l-gulose from GDP-mannose. In this study, the gene and transcript encoding GME from the red alga Gracilaria changii (GcGME) were cloned. The structural gene sequence of GcGME is devoid of an intron. The cis-acting regulatory element involved in light response is the most abundant element at the 5′-flanking region of GcGME. The open reading frame of GcGME consists of 1,053 nucleotides with 351 amino acids. This cDNA was cloned into pET32a expression vector for recombinant protein production in Escherichia coli. High yield of soluble recombinant GcGME (55 kDa) was expressed upon isopropyl β-d-1-thiogalactopyranoside induction. The enzyme activity of recombinant GcGME was detected using thin layer chromatography and high-performance liquid chromatography. The transcript abundance of GcGME was the highest in G. changii and the lowest in Gracilaria salicornia corresponding to their agar contents. The characterization of GcGME from G. changii is important to facilitate the understanding of its role in agar production of this seaweed.
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Law, A. T.; Robertson, B. R.; Dunker, S. S.; Button, D. K.
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Analysis of continuous culture methodology suggests that this potentially powerful tool for kinetic analysis can be improved by minimizing several inherent shortcomings. Medium background substrates — organic carbon, phosphate, and manganese — were shown to dominate kinetic observations at concentrations below chemical detection methods. Reactor wall growth, culture size distribution changes, sample removal-induced steady state perturbations, and limiting substrate leakage from organisms are treated in terms of kinetic measurement errors. Large variations in maximal growth rates and substrate uptake rates found are attributed to experimental protocol-induced transient states. Relationships are presented for correcting limiting substrate concentrations for lability during sampling, contamination with unreacted medium, and background substrate effects. Analytical procedures are discussed for improved measurement of limiting substrate kinetics involving enzymes, isotopes, and material balance manipulation. Relaxation methods as applied to continuous culture are introduced as a means for isolating separate rate constants describing net substrate transport and for evaluating cellular metabolite leakage. Low velocity growth, multiple substrate metabolism, and endogenous metabolism are discussed along with measurements showing that 1-month generation times for aquatic microorganisms can be quite normal and that the kinetics are compatible withμg/liter limiting substrate concentrations. The concept of regarding growth kinetics as the sum of several net accumulation processes is suggested.
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Darah, I.; Ibrahim, C. O.
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The production of lignin-degrading enzymes by free and entrapped cells ofPhanerochœte chrysosporium in a tubular air-lift bioreactor was studied. Under optimized cultural conditions the production of lignin peroxidase by free cells, calcium-alginate-entrapped cells and scouring-mesh-entrapped cells was in a ratio of 520∶720∶950 mU/mL, while the production of manganese peroxidase was in a ratio of 350∶480∶620 mU/mL. The stability of the entrapped cells by fed-batch systems was highest after 3 feeding experiments which is similarly demonstrated in the repeated use of the preparations in batch system.
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Ratnasingam, J.; Wagner, K.
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A survey of ISO 14001 certified and non-certified wooden furniture manufacturers in Malaysia revealed that the low cost-benefit factor was the main reason that deterred the adoption of the standard. However, the adoption of ISO 14001 resulted in the production of green furniture, the use of environmental friendly materials and technologies, retraining of the workers and waste reduction. Consequently, the adoption of the ISO 14001 environmental management system resulted in a more cost-effective wooden furniture production, contrary to previous perception.
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Sharifah, Noor Akmal Syed Husain; Zakaria, Zubaidah; Chia, Wai Kit
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Fluorescence in situ hybridization (FISH) is increasingly gaining importance in clinical diagnostics settings. Due to the ability of the technique to detect chromosomal abnormalities in samples with low cellularity or containing a mixed population of cells even at a single-cell level, it has become more popular in cancer research and diagnosis. Here, we describe the FISH technique for detection of PAX8-PPARγ translocation in follicular thyroid neoplasms, and the optimal protocol for the detection of this fusion gene using in archival formalin-fixed paraffin-embedded (FFPE) thyroid tissue sections.
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Tan, H.
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The general combining ability (GCA) of parents for latex yield (0.7–14.4) and vigour (0.7–3.6) of young Hevea seedlings from the Phase V breeding programme of the RRIM were estimated. The GCA yield values were compared with the GCAs of different seedling populations in the mature phase. Results suggest that nursery data can be used to identify potential parents for futurecrosses. Further work will help significantly to shorten the breeding cycle in Hevea.
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Varkkey, Helena
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Peatlands in Indonesia are protected by regulations that forbid the conversion of these lands into plantations. However, peat fires here have been found to be a major source of smoke that travels across national boundaries creating regional haze. Despite these regulations, more than a quarter of all Indonesian oil palm plantations are on peat. This paper argues that patronage networks within the Indonesian oil palm sector have been a major factor in the unsustainable use of peatlands there. Rampant patronage politics have made it easy for well-connected companies to skirt regulations to obtain licenses for these lands. Decentralization has further encouraged this practice at the regional level, as regional elites are eager to reap the benefits of local investments. In addition, clients are able to exert their influence over state decision-making to ensure that any changes to the licensing process does not jeopardize their access to these lands. These converted lands are highly fire-prone. Furthermore, some companies have been found to use fire as a cheap way to clear the land for planting. Hence, this paper argues that transboundary haze in Southeast Asia can be traced back to the ongoing oil palm boom in Indonesia, bolstered by patronage networks.
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Zadeh, Sh. Shakiba; Christianus, A.; Saad, C.R.; Hajeb, P.; Kamarudin, M.S.
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The three Southeast Asian horseshoe crab species are diminishing not only locally but also regionally and protection of them is now an urgent matter. Two species of horseshoe crab, Tachypleus gigas and Carcinoscorpius rotundicauda, were artificially inseminated, and the eggs were incubated at 28±1°C and in the salinity of 33±2 ppt. The fertilized eggs hatched after 42 days and 41 days with hatching rates of 98.1 and 98.9% for T. gigas and C. rotundicauda, respectively. This study reveals that in the identical laboratory condition, C. rotudicauda underwent more frequent molting than T. gigas. After 328 days of rearing, 63.8 and 22.9% of C. rotundicauda larvae had molted to the 6th and 7th instars, respectively, while 56.6 and 20.1% of T. gigas at the end of 355 days of rearing had molted to the 5th and 6th instars, respectively, but only 0.6% had molted to the 7th instar. There is a wide variation in the molting rate among larvae obtained from synchronized inseminated eggs and reared under uniform laboratory conditions.
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Chu, Wan-Loy; Phang, Siew-Moi; Goh, Swee-Hock
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The effects of nitrate and silicate levels, and carbon source on growth, biochemical composition and fatty acid composition ofNitzschia inconspicua were investigated using batch cultures. Within the range of silicate levels supplied (8.8–176 μM), no marked variations in growth trend, biochemical composition or fatty acid composition were shown. Biomass at stationary phase, ranging from 64–66 mg ash-free dry weight (AFDW) L−1, and specific growth rate (μ) based on chlorophylla (0.41–0.50 d−1) of the cultures grown within 0.3–3.0 mM NaNO3 were not significantly different. Cultures supplemented with glucose (0.1 % w/v), acetate (0.1 % w/v) or 5% CO2 attained higher biomass (85, 85, 97 mg AFDW L−1) than the control which was grown in synthetic seawater and agitated by magnetic stirring. Cells grown at <3.0 mM NaNO3 contained higher carbohydrate contents (14.8–21.5% AFDW) than those grown at 3.0 mM (4.0% AFDW). Lipid content increased at the expense of proteins in cells aerated with 5% CO2. The dominant fatty acids, 16:0 and 16:1, ranged from 35.7–45.0% and 36.4–45.4% total fatty acids (TFA), respectively, while the relative proportions of 20:4 (n-6) and 20:5 (n-3) ranged from 1.7–5.4% and 3.4–5.9% TFA respectively. Cultures aerated with 5% CO2 attained the highest biomass (97 mg AFDW L−1) and yield of 20:5 (n-3) (0.34 mg L−1).
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Okuda, Toshinori; Kachi, Naoki; Kheong Yap, Son; Manokaran, N.
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Three analyses of species diversity in a lowland dipterocarp forest were conducted to examine whether the nature of forest community dynamics are determined by density-dependent recruitment and mortality of saplings with a data set obtained in a 50 ha plot in Pasoh Forest Reserve. The first analysis examined whether sapling density varied as a function of distance from the nearest conspecific adult. The second analysis assessed the relationship between the spatial distribution patterns of saplings and adult trees. A third analysis examined sapling recruitment and mortality based on data from 2 censuses, taken in 1985 and 1990. Four hundred forty-four species (each with more than 100 individuals) out of the total of 814 species recorded in the plot, were chosen for the analyses. Of these selected species, 56 species showed significant reduction in sapling densities close to the conspecific adults. Within this group, 11 species were in the emergent layer (29.0% of the total species in this layer), 17 were in the canopy layer (10.5%), 18 were in the understory layer (11.3%), and 10 were in treelet and shrub layer (11.8%). In contrast, the sapling densities of 53 species decreased with increasing distance from conspecific adults; 2 of these species were in the emergent layer (5.2% of the total species in this layer), 14 were in the canopy layer (8.6%), 21 were in the understory layer (13.2%), and 16 were in the treelet and shrub layer (18.8%). The saplings of 35 of the 444 total selected species were clumped, while adults were regularly or randomly distributed. Of the remaining species, in 183 species (41.2%), the distributions of both adults and saplings were clumped. Thus, these 2 analyses do not support the prediction that most of the species of lowland tropical forests fail to produce new adults in their vicinity and as a result of this, adult trees are more regularly distributed than their conspecific juveniles (Janzen 1970). In the third analysis, the recruitment of saplings of species in the emergent and canopy layers increased significantly and in proportion with mortality, suggesting that the dominant species suffer higher mortality than do less common species. This trend is not so apparent in the understory, and the treelet and shrub layers. The results imply that a dynamic equilibrium process, which prevents competitive exclusion and maintains space for minor species, may be active among the species in the upper layers (particularly the emergent layer); however, such a dynamic equilibrium condition is not due exclusively to the reduced recruitment of saplings near conspecific adults, and the dynamic equilibrium condition is not prevalent among the lower story species.
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Mansor, Marzalina
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Conservation of forest ecosystems in majority of Southeast Asia countries faces several major challenges. Coverage of protected areas is not adequate often exist as islands, surrounded by densely populated areas with incompatible land uses. Besides that a successful long-term conservation of forestry species even in their own natural ecosystems requires a good understanding of the ecological interactions between species, and the challenges begin with the surveying and inventorying of existing resources. Thus comparative studies at species level and intraspecific levels of reproductive output, mating patterns and regeneration processes involving trees in large contiguous forests and small fragments will pose challenges to conserve forest ecosystems. Additional research aiming at the development of ex situ conservation techniques, including slow growth storage and cryopreservation, and at the understanding of the biological mechanisms determining recalcitrance of species conserved is also required.
While timber is economically the most important forest product, many other products are valued both on world markets and by local people. Conserving natural forests is not only for biodiversity but also of the important role played by in the provision of environmental and social services. Strengthening the role of the timber industry in biodiversity conservation will require improvements in collaborations between the timber industry and local communities, as well as the providing the alternatives to sustain the need of timber industry. The innovation of engineered lumber from the waste biomass will be an option to be considered in the era of green wood technology.
Although numerous initiatives both national and international bodies are working together with SEA countries to address the variety of issues related to forest genetic conservation there are still lack of coordination between and among external agencies and international donors for most of the initiatives. Many of the duplication of activities are seen to be occurred in countries that have substantial infrastructure and government support as compared to poor countries in SEA.
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Barber-Riley, G.
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Résumé
La capacité, l'écoulement, la pression et la concentration de la bile ont été mesurés chez des rats dont le régime contenait de l'éthionine. Les résultats obtenus montrent que: (1) La BSP et l'E.G. bleu sont produits seulement par les cellules hépatiques; (2) la bile provient de deux ou de plusieurs sécrétions; (3) les ductules qui apparaissent dans le foie après administration d'éthionine fonctionnent normalement.
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Paterson, Alistair; Kassim, Angzzas; McCallum, Susan; Woodhead, Mary; Smith, Kay; Zait, Dzeti; Graham, Julie
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Raspberry volatiles are important for perceptions of sensory quality, mould resistance and some have nutraceutical activities. Twelve raspberry character volatiles were quantified, 11 of them in fruit from two seasons, from plants from the Glen Moy × Latham mapping population growing in both open field and under cover (polytunnels). Effects of season and environment were examined for their impact on the content of α-ionone, α-ionol, β-ionone, β-damascenone, linalool, geraniol, benzyl alcohol, (Z)-3-hexenol, acetoin, acetic and hexanoic acids, whilst raspberry ketone was measured in one season. A significant variation was observed in fruit volatiles in all progeny between seasons and method of cultivation. Quantitative trait loci were determined and mapped to six of the seven linkage groups, as were candidate genes in the volatiles pathways.
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Nesaretnam, Kalanithi; Guthrie, Najla; Chambers, Ann F.; Carroll, Kenneth K.
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The tocotrienol-rich fraction (TRF) of palm oil consists of tocotrienols and some α-tocopherol (α-T). Tocotrienols are a form of vitamin E having an unsaturated side-chain, rather than the saturated side-chain of the more common tocopherols. Because palm oil has been shown not to promote chemically-induced mammary carcinogenesis, we tested effects of TRF and α-T on the proliferation, growth, and plating efficiency (PE) of MDA-MB-435 estrogen-receptor-negative human breast cancer cells. TRF inhibited the proliferation of these cells with a concentration required to inhibit cell proliferation by 50% of 180 μg/mL, whereas α-T had no effect at concentrations up to 1000 μg/mL as measured by incorporation of [3H]thymidine. The effects of TRF and α-T also were tested in longer-term growth experiments, using concentrations of 180 and 500 μg/mL. We found that TRF inhibited the growth of these cells by 50%, whereas α-T did not. Their effect on the ability of these cells to form colonies also was studied, and it was found that TRF inhibited PE, whereas α-T had no effect. These results suggest that the inhibition is due to the presence of tocotrienols in TRF rather than α-T.
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Yamauchi, K.; Ishida, Y.; Hashim, R.; Heinze, J.
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Abstract.
Queens and female sexuals of the Southeast Asian ant Cardiocondyla sp. engage in aggressive interactions. By biting and violently antennating female sexuals, queens appear to prevent them from shedding their wings and presumably also from starting to lay haploid eggs. Aggression among dealate queens apparently results in the establishment of reproductive rank orders with considerable differences in offspring production among individual nestmate queens, as visualized by the pronounced color polymorphism of this taxon. Reproductive skew ranged from complete monopolization of both worker and female sexual production to more or less equal partitioning of reproduction. Division of reproduction was associated with variation in the location of queens close to or away from the center of the brood pile, which again appeared to be caused by queen-queen antagonism.
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Itino, Takao; Davies, Stuart J.; Tada, Hideko; Hieda, Yoshihiro; Inoguchi, Mika; Itioka, Takao; Yamane, Seiki; Inoue, Tamiji
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Cospeciation, in which both parties of an ecological interaction speciate in parallel with each other, has rarely been reported in biotic associations except the cases for host–parasite interaction. Many tropical plants house ants and thereby gain protection against herbivores. Although these ant–plant symbioses have been regarded as classical cases of coevolved mutualism, no evidence of cospeciation has been documented. The Asian ant–plant association between Crematogaster ants and Macaranga plants is highly species specific and the molecular phylogeny of the ants parallels the plant phylogeny, reflecting history of cospeciation. Evidence is presented that this association has been maintained over the past seven million years. Phylogeographic patterns of 27 ants from two Macaranga species suggest that allopatric cospeciations are still in progress in Asian wet tropics.
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Jagani, Hitesh; Rao, Josyula Venkata; Palanimuthu, Vasanth Raj; Hariharapura, Raghu Chandrashekar; Gang, Sagar
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Overexpression of anti-apoptotic Bcl-2 is often observed in a wide variety of human cancers. It prevents the induction of apoptosis in neoplastic cells and contributes to resistance to chemotherapy. RNA interference has emerged as an efficient and selective technique for gene silencing. The potential to use small interfering RNA (siRNA) as a therapeutic agent for the treatment of cancer has elicited a great deal of interest. However, insufficient cellular uptake and poor stability have limited its therapeutic applications. The purpose of this study was to prepare chitosan nanoparticles via ionic gelation of chitosan by tripolyphosphate for effective delivery of siRNA to silence the anti-apoptotic Bcl-2 gene in neoplastic cells. Chitosan nanoparticles loaded with siRNA were in the size range 190 to 340 nm with a polydispersive index ranging from 0.04 to 0.2. They were able to completely bind with siRNA, provide protection against nuclease degradation, and enhance the transfection. Cell culture studies revealed that nanoparticles with entrapped siRNA could efficiently silence the antiapoptotic Bcl-2 gene. Studies on Swiss albino mice showed that siRNA could be effectively delivered through nanoparticles. There was significant decrease in the tumor volume. Blocking the expression of anti-apoptotic Bcl-2 can enhance the sensitivity of cancerous cells to anti-cancer drugs and the apoptosis rate. Therefore, nanoformulations with siRNA can be promoted as an adjuvant therapy in combination with anti-cancer drugs.
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Moghaddam, Behrouz Ehsani; Taha, Rosna Mat
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The present study diseusses the results of cytological studies of two kinds of sugar beet callus, i.e., embryogenic and non-embryogenic tissues. The calluses were produced through culture of secondary leaves on Murashige and Skoog medium containing two hormone combinations. One week after transfer of calluses onto fresh medium, their cells were viewed using electron microscopy and an image analyzer. Observations showed that cells of the two callus types had considerable differences in cell structure and various organelles. Of note were the high amount of polyploidization, rough endoplasmic reticulum, polysome, poly-nucleolus, and incomplete cell wall together with abnormal partitioning in non-embryogenic cells, as compared to embryogenic cells. In contrast, vacuolation of cytoplasm, perfect cell wall and partitioning structure, and the high proportion of nucleus/cytoplasm area were recognized in embryogenic cells.
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Myaing, Tin Tin; Saleha, A.A.; Arifah, A.K.; Raha, A.R.
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Escherichia coli isolates from 131 raw chicken meat samples were tested for susceptibility to 12 antibiotics. Plasmids were isolated from many samples and their DNA molecular weight calculated. An 81.7% plasmid occurrence rate was observed among the isolates, ranging from 0 to 8 in number and with sizes from 1.2 to 118.6 MDa. Plasmids were detected in 93.8% of E. coli isolates resistant to all 12 antibiotics, and in 90.5% of E. coli isolates resistant to 11. Three (2.8%) isolates harboured 8 plasmids and were resistant to all 12 antibiotics. Antibiotic resistant genes in bacteria are usually carried in extrachromosomal DNA and it is postulated that E. coli with a high number of plasmids possesses wider resistance to antibiotics.
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Tan, Keng Hong; Tan, Lin Tze; Nishida, Ritsuo
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It is widely believed that most orchid flowers attract insects by using deception or chemical rewards in the form of nectar. Flowers of Bulbophyllum vinaceum produce a large array of phenylpropanoids that lure tephritid fruit fly males and also act as floral reward, which the flies subsequently convert to pheromone components. The major floral volatile components identified are methyl eugenol (ME), trans-coniferyl alcohol (CF), 2-allyl-4,5-dimethoxphenol (DMP), and trans-3,4-dimethoxycinnamyl acetate, whereas the minor components are eugenol, euasarone, trans-3,4-dimethoxy cinnamyl alcohol, and cis-coniferyl alcohol. Among the various floral parts, the lip (which is held in a closed position up against the sexual organs) has the highest concentration of the major compounds. An attracted male fly normally lands on one of the petals before climbing up onto and forcing the “spring loaded” floral lip into the open position, hence exposing the floral sexual organs. The architecture and location of chemical attractants of the lip compel the fly to align itself along the lip’s longitudinal axis in a precise manner. As the fly laps up the compounds and moves towards the base of the lip, it passes the point of imbalance causing the lip to spring back to its normal closed position. The fly is catapulted headfirst into the column cavity, and its dorsum strikes the protruding sticky base of the hamulus and adheres to it. The momentum of the fly and the structural morphology of the long stiff hamulus act to pry out the pollinia from its anther cover. Hence, the pollinarium (pollinia + hamulus) is detached from the flower and adhered to the fly’s dorsum. In this unique mutualistic association, both species receive direct reproductive benefits—the flower’s pollinarium is transported for cross pollination, and the fly is offered a bouquet of phenylpropanoids (synomone) that it consumes, converts, and/or sequesters as sex pheromonal components, thus enhancing sexual attraction and mating success.
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Yule, Catherine M.; Gomez, Lalita N.
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It has long been assumed that the peat underlying tropical peat swamp forests accumulates because the extreme conditions (water logged, nutrient poor, anaerobic and acidic—pH 2.9–3.5) impede microbial activity. Litterbag studies in a tropical Malaysian peat swamp (North Selangor peat swamp forest) showed that although the sclerophyllous, toxic leaves of endemic peat forest plants (Macaranga pruinosa, Campnosperma coriaceum, Pandanus atrocarpus, Stenochlaena palustris) were barely decomposed by bacteria and fungi (decay rates of only 0.0006–0.0016 k day−1), leaves of M. tanarius, a secondary forest species were almost completely decomposed (decay rates of 0.0047–0.005 k day−1) after 1 year. Thus it is intrinsic properties of the leaves (that are adaptations to deter herbivory in the nutrient poor environment) that impede microbial breakdown. The water of the peat swamp was very high in dissolved organic carbon (70–84 mg l−1 DOC). Laboratory studies revealed initial rapid leaching of DOC from leaves (up to 1,720 mg l−1 from 4 g of leaves in 7 days), but the DOC levels then fell rapidly. The leaching of DOC resulted in weight loss but the physical structure of the leaves remained intact. It is suggested that the DOC is used as a substrate for microbial growth hence lowering the concentration of DOC in the water and transferring energy from the leaves to other trophic levels. This would explain how nutrient poor tropical peatswamps support diverse, abundant flora and fauna despite low nutrient levels and lack of rapid litter cycling such as occurs in other types of tropical rainforests.
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Jackson, Colin R.; Liew, Kong Cheng; Yule, Catherine M.
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Tropical peat swamp forests are important and endangered ecosystems, although little is known of their microbial diversity and ecology. We used molecular and enzymatic techniques to examine patterns in prokaryotic community structure and overall microbial activity at 0-, 10-, 20-, and 50-cm depths in sediments in a peat swamp forest in Malaysia. Denaturing gradient gel electrophoresis profiles of amplified 16S ribosomal ribonucleic acid (rRNA) gene fragments showed that different depths harbored different bacterial assemblages and that Archaea appeared to be limited to the deeper samples. Cloning and sequencing of longer 16S rRNA gene fragments suggested reduced microbial diversity in the deeper samples compared to the surface. Bacterial clone libraries were largely dominated by ribotypes affiliated with the Acidobacteria, which accounted for at least 27–54% of the sequences obtained. All of the sequenced representatives from the archaeal clone libraries were Crenarchaeota. Activities of microbial extracellular enzymes involved in carbon, nitrogen, and phosphorus cycling declined appreciably with depth, the only exception being peroxidase. These results show that tropical peat swamp forests are unusual systems with microbial assemblages dominated by members of the Acidobacteria and Crenarchaeota. Microbial communities show clear changes with depth, and most microbial activity is likely confined to populations in the upper few centimeters, the site of new leaf litter fall, rather than the deeper, older, peat layers.
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Javed, M.A.; Chai, M.; Othman, R.Y.
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Suckers collected from different populations of Musa acuminata ssp. malaccensis were found to be highly resistant to race 4 of Fusarium oxysporum f. sp. cubense (FOC) suggesting that local wild banana populations co-evolved with the pathogen. Seedlings from these wild banana plants segregated for resistance to the pathogen. The infected seedlings were characterized based on external and internal symptoms and the variable response to FOC was mainly due to the genetic factors. Using the technique of random amplified polymorphic DNA (RAPD), 96 major amplification products from 15 primers were identified. Only 10 out of 96 markers were monomorphic and shared among the seed progenies, whereas the remaining 86 were highly polymorphic. Three primers showed banding patterns specific to resistant or susceptible seedlings. These results showed the great potential of the wild Musa acuminata ssp. malaccensis as a source for banana improvement and also for the synthesis of segregating populations for linkage mapping, gene cloning and DNA markers related to FOC resistance.
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Eck, Gero; Fiala, Brigitte; Linsenmair, Karl Eduard; Bin Hashim, Rosli; Proksch, Peter
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The plant genus Macaranga is known for its manifold mutualistic associations with ants. The plants provide food for the ants and in turn get protection from herbivores. Depending on the strength of the plant–ant interaction, the plant's investment in ants and the biotic defense derived from them is more or less effective. We conducted a comparative study on tannin content in 12 Macaranga species that were selected based on their associations with ants (three nonmyrmecophytes and nine myrmecophytes, three of which start their ontogeny as nonmyrmecophytes). Different developmental stages were investigated in three Macaranga species. Extracts of every individual plant analyzed for tannins were also tested for their effects on larval growth employing larvae of the common cutworm (Spodoptera littoralis). The studied Macaranga species differed significantly in their tannin contents as well as in the effects of their leaf extracts on the growth of S. littoralis larvae. A correlation analysis shows a connection between tannin contents and larval growth. High tannin contents and, thus more effective chemical defense, were observed in nonmyrmecophytic Macaranga species associated only facultatively with ants as compared to obligate myrmecophytes. Our study supports the hypothesis of a trade-off between chemical and biotic defense in the genus Macaranga.
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ABDULLAH, S.A.; NAKAGOSHI, N.
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Oil palm industry is one of the major revenue for economic development in Malaysia. Oil palm was introduced to Malaysia in 1911 and the first commercial planting began in 1917. Since then and combined with increasing demand of its product both at the local and international market, areas planted with oil palm has been expanded throughout the nation. In 2004, oil palm plantation covered approximately 9.9% of the total Malaysian land area. However, its expansion has been recognised intrude into forested areas. This situation has been debated as one of the major international issues that cause forest degradation and loss of biodiversity. To balance between economic importance and conservation of forested areas a practical approach in planning and managing oil palm land use is necessary. Landscape ecological approach is an emerging pathway to achieve the goal and increasingly recognised as tool in various aspects of planning and managing land use. In this chapter, the land use changes of this premier man-influenced area in Malaysia will be analysed. How landscape ecology concepts can be integratedinto planning and managing oil palm land use for forest conservation in Malaysia will be discussed.
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Ohtani, Masato; Ueno, Saneyoshi; Tani, Naoki; Lee, Leong Soon; Tsumura, Yoshihiko
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We developed microsatellite markers from newly isolated expressed sequence tags of an endangered tropical tree species, Shorea leprosula (Dipterocarpaceae). Twenty-four loci exhibited clear, polymorphic amplification patterns among 52 individuals from a population in Indonesia, with two to 16 alleles per locus. No locus showed significant departure from Hardy–Weinberg equilibrium, and no significant genotypic disequilibrium was detected for any pair of loci after sequential Bonferroni correction.
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Oliver, J. K.; Berkelmans, R.; Eakin, C. M.
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Large-scale coral bleaching was recorded as early as 1931, but severe bleaching on a regional or global scale was not documented until 1983. We use records from a global database of bleaching records to show that severe bleaching events occurred at a global level on four recent occasions and demonstrate that these events occurred in close temporal proximity to a strong negative deviation in the Southern Oscillation Index. While there was no clear increase in the frequency or intensity of major global bleaching events, the number of bleaching records clearly increased during the past three decades. However, increased vigilance and reporting of mild bleaching by an ever-increasing number of researchers and conservation-minded divers has confounded efforts to definitively separate changes in bleaching frequency from changes in reporting.
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Lim, L. H. S.; Gibson, David I.
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Sundatrema langkawiense n. g., n. sp. (Monogenea: Ancyrocephalidae) is described from the gills of the orbfish Ephippus orbis (Bloch) (Ephippidae) off the Island of Langkawi, Malaysia, in the Andaman Sea. This new genus has the ancyrocephalid characteristics of four anchors, 14 marginal hooks and two bars, but differs from other four-anchored monogenean genera, and notably from Parancylodiscoides Caballero & Bravo Hollis, 1961 (found on the ephippids Chaetodipterus spp. off Central and South America), by having a unique combination of features. These include a muscular genital sucker and a vas deferens and vagina on the same (sinistral) side of the body. It is similar to Parancylodiscoides in having four haptoral reservoirs opening at the anchoral apertures, four anchors, similar connecting bars and small marginal hooks. The new species is characterised by the above generic features and by possessing a small, short copulatory organ lacking an accessory piece. Diplectanum longiphallus MacCallum, 1915 (previously attributed to Ancyrocephalus Creplin, 1839, Tetrancistrum Goto & Kikuchi, 1917 and Pseudohaliotrema Yamaguti, 1953) is transferred to Parancylodiscoides as P. longiphallus (MacCallum, 1915) n. comb.
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Molnár, K.; Shaharom-Harrison, F.; Székely, Cs.
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Ninety-five specimens of 14 freshwater fish species from small streams in the Kuala Terengganu district and the Lake Kenyir Reservoir, Malaysia, were surveyed for coccidian infections. Six fish species proved to be infected with apicomplexans belonging to the genus Goussia. In all of these fishes Goussia species were found in unsporulated and semisporulated stages. Oöcysts of four species inhabiting the intestinal epithelium became sporulated in tap-water within 24 hours. In two fish species sporulation failed and only unsporulated oöcysts were recorded in the intestine. Three of the intestinal species finishing sporulation proved to be new to science and were described as Goussia malayensis n. sp., G. bettae n. sp. and G. pogonognathi n. sp. from Apocheilus panchax, Betta splendens and Hemirhamphodon pogonognatus, respectively. The fourth species, found in Trichogaster pectoralis, was identified as G. trichogasteri Székely & Molnár, 1992, a species known from aquarium-cultured T. trichopterus.
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Chai, Tsun-Thai; Simmonds, Daina; Day, David A.; Colmer, Timothy D.; Finnegan, Patrick M.
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The alternative oxidase mediates the cyanide-resistant respiratory pathway in plant mitochondria. In non-thermogenic plants, the role of alternative oxidase in plant growth and development is not well understood. Soybean (Glycine max) lines carrying a GmAOX2b antisense gene had compromised vegetative growth and reproductive performance under typical glasshouse growth conditions. The reduction in vegetative growth was demonstrated by reduction in shoot height, the number of leaves per plant and the green leaf area. Antisense plants also had decreased pod formation and seed to pod ratios, which together led to a reduction in the number and total mass of seed produced. The negative effects of the antisense gene on pod set, seed set, ovule availability and total seed mass were primarily confined to the branches, rather than the main stem. The preferential effect of alternative oxidase suppression in the branches is discussed in relation to the reproductive potential of soybean under stress. Taken together, these results demonstrate that alternative oxidase provides the benefit of sustaining plant vegetative growth and reproductive capacity in soybean.
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Chu, A. C. P.; Robertson, A. G.
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In a glasshouse experiment, single plants of ten-weeks old white clover (Trifolium repens L.) were subjected to two levels of shading and two levels of defoliation. Nodulation and nitrogen fixation parameters were measured at six sequential harvest over four weeks.
Changes in nodule number and hence nodule dry weight per plant were due to nodule decay, sloughing off and non-production and were closely related to losses in root dry weight.
Severe defoliation caused degradation of leghaemoglobin, an effect which was seen in less than three days from treatment. It led also to a temporary but marked decrease in the nitrogen fixation capacity of the nodules as measured by the acetylene reduction assay. Recovery of normal activity by the nitrogenase system took about ten days.
The effects of shading and defoliation on the pattern of nodulation have been described briefly.
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Ramanoon, Siti Zubaidah; Robertson, Ian Duncan; Edwards, John; Hassan, Latiffah; Md Isa, Kamaruddin
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This is a retrospective study of the outbreaks of foot-and-mouth disease (FMD) in Peninsular Malaysia between 2001 and May 2007. In total, 270 outbreaks of FMD were recorded. Serotype O virus (89.95 %) and serotype A (7.7 %) had caused the outbreaks. Significant differences on the occurrence of FMD were found between the years (t = 5.73, P = 0.000, df = 11), months (t = 4.7, P = 0.000, df = 11), monsoon season (t = 2.63, P = 0.025, df = 10) and states (t = 4.84, P = 0.001, df = 10). A peak of outbreaks observed in 2003 could be due to increased animal movement and the other peak in 2006 could be due to a compromised FMD control activities due to activities on the eradication of highly pathogenic avian influenza. Cattle (86 % of outbreaks) suffered the most. However, no difference in disease occurrence between species was observed. The populations of cattle (r = 0.672, P = 0.023) and sheep (r = 0.678, P = 0.022) were significantly correlated with occurrence of FMD. Movement of animals (66 % of outbreaks) was the main source for outbreaks. A combination of control measures were implemented during outbreaks. In conclusion, the findings of this study show that FMD is endemic in Peninsular Malaysia, and information gained could be used to improve the existing control strategy.
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Kitayama, Kanehiro; Ong, Robert C.; Lee, Ying Fah
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Comparisons between the consequences of improved management and those of conventional logging in terms of carbon stock and biodiversity conservation were conducted in the Deramakot Forest Reserve versus the Tangkulap Forest Reserve, where lowland dipterocarp forest is the natural vegetation (see also Imai et al. 2009). In this chapter, we summarize the co-benefits of improved forest management for biodiversity conservation and carbon sequestration. We evaluate the co-benefits in terms of additionality, which is the net increment effect of the improved forest management added over 13 years from 1989 (when logging was suspended in Deramakot) until 2002 (when our analyses started) in comparison to continued high-impact conventional logging.
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Lai, Kok Song; Yusoff, Khatijah; Mahmood, Maziah
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Recently, the use of plants for the production of recombinant proteins has been well demonstrated with promising outcomes. In this study, an efficient Nicotiana tabacum L. cv. Bright Yellow 2 (BY-2) cells system expressing the ectodomain of hemagglutinin-neuraminidase (eHN) protein from Newcastle disease virus (NDV) strain AF2240 was established. Transgenic tobacco BY-2 cell cultures expressing the immunogenic eHN protein were generated and the translation efficiency of eHN protein was enhanced using the 5′-untranslated region of Nicotiana tabacumalcohol dehydrogenase gene (NtADH 5′-UTR) under the control of strong cauliflower mosaic virus (CaMV 35S) promoter. Transgenic lines verified by real-time PCR showed high level of eHN mRNA transcripts and immunoblotting confirmed the presence of 66 kD eHN protein. The eHN protein was stably produced in an average of 0.2–0.4 % total soluble protein. Green fluorescent protein-tagged eHN protein was expressed and localized at the cytosol of BY-2 cell. All mice receiving purified eHN protein from transgenic tobacco BY-2 cells produced specific anti-NDV antibodies. We concluded that plant made eHN elicit immune response and can serve as candidate vaccine against NDV.
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Oo, Khaik-Cheang; Teh, Sau-Keen; Khor, Hun-Teik; Ong, Augustine S. H.
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Oil palm (E. guineensis) fruits at three stages of development were studied. At week 12–13 after anthesis, the endosperm had started accumulating oil and tissue slices incorporated [1-14C] acetate into fatty acids which resembled those found in the mature endosperm. The mesocarp contained very little oil and incorporated acetate into polar lipids. At week 16–17, the mesocarp started to accumulate oil; this was reflected in the [14C] lipid products from acetate incubation. At or just prior to this stage, an increase in the endogenous linoleic and linolenic acid content and the increase in fruit size indicated cellular growth in the mesocarp tissue. At week 20–21 the fruit was ripe, and both endosperm and mesocarp tissues were filled with storage oil. [14C] Fatty acids synthesized from acetate by mesocarp slices at this stage were the same as the endogenous storage fatty acids in bothE. guineensis andE. oleifera. A very weak fatty acid synthesizing activity was seen in the mature endosperm, but the products had no relationship to the storage lipid.
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Moein, Sara
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In this paper, application of Artificial Neural Network (ANN) for electrocardiogram (ECG) signal noise removal has been investigated. First, 100 number of ECG signals are selected from Physikalisch-Technische Bundesanstalt (PTB) database and Kalman filter is applied to remove their low pass noise. Then a suitable dataset based on denoised ECG signal is configured and used to a Multilayer Perceptron (MLP) neural network to be trained. Finally, results and experiences are discussed and the effect of changing different parameters for MLP training is shown.
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Yu, Chew-Hock; Lim, Phaik-Eem; Phang, Siew-Moi
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Gracilaria edulis and Gracilaria tenuistipitata var liui are agarophytes with high commercial value which are currently cultivated in countries like India and Thailand. They have great potential for mariculture in Malaysia. Experiments were carried out to study carpospore germination and determine the effects of irradiance and salinity on the growth of these two species. Both species showed the Dumontia type of carpospore development. Both species showed increased daily growth rate (% day−1) with increasing irradiance and tolerance for a wide range of salinity with a preference for low salinity. G. edulis grew best at 100 μmol photons m−2 s−1 and 15 psu while G. tenuistipitata var liui grew best at 60–130 μmol photons m−2 s−1 and 15 psu. The highest growth rate obtained for G. edulis and G. tenuistipitata var liui was 13.57 and 19.7 % day−1 respectively. tenuistipitata var liui. ANOVA showed that both irradiance and salinity have significant effect on the growth of both species (P < 0.05). The results showed that G. tenuistipitata var liui is a good candidate for mass cultivation in Malaysian brackish waters. Besides, this study also showed the feasibility of using spore culture to provide stocks for sustainable farming of Gracilaria.
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Yeoh, Suat Hui; Bell, J. Charlie; Foley, William J.; Wallis, Ian R.; Moran, Gavin F.
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Eucalyptus globulus Labill is a foundation tree species over its disjunct distribution in southeastern Australia. The quality of its pulp makes it the most important hardwood species in the world. The importance of E. globulus prompted the establishment of common gardens from seed collected across its geographic range. This enabled us to study the genetic structure of the species, its population boundaries, and gene flow using 444 trees from different open-pollinated families that were genotyped at 16 microsatellite loci. A Bayesian clustering method was used to resolve five genetically distinct groups across the geographical range. These groups were identified as regions, which varied in diameter from 38 to 294 km and contain 4 to 16 putative populations. For two of these regional groups, we used spatial autocorrelation analysis based on assignment of trees to their natural stands to examine gene flow within each region. Consistent significant local-scale spatial structure occurred in both regions. Pairs of individuals within a region showed significant genetic similarity that extended beyond 40 km, suggesting distant movement of pollen. This suggests that breeding populations in E. globulus are much bigger than traditionally accepted in eucalypts. Our results are important for the management of genetic diversity and breeding populations in E. globulus. Similar studies of a variety of eucalypts pollinated by insects and birds will determine whether the local-scale genetic structure of E. globulus is unusual.
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Goh, S. H.; Chuah, C. H.; Vadiveloo, J.; Tho, Y. P.
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Soldiers of free-ranging termites of the genusLacessititermes (Isoptera, Nasutitermitinae) secrete from their frontal glands a mixture of monoterpenes, sesquiterpenes, and diterpenes.Lacessititermes ransoneti, L. laborator, andL. species A produce species-specific secretions, the composition being most complex forL. laborator. Apart from known mono- and dihydroxytrinervitadienes, the following new diterpenes were isolated and tentatively assigned as trinervita-1(15),8(19)-dien-2β,3α,9α,14α-tetraol 2,3,14-O-triacetate, trinervita-1(15),8(19)-dien-2β,3α,9β,14α-tetraol 2,3,14-O-triacetate, 2β,3α,9α, 14α-tetraacetoxy-1 (15), 8(19)-trinervitadiene, and 2β,3α,11α,13α-tetraacetoxy-1(15),8(19)-trinervitadiene. Data on intragenus chemical variations were subjected to canonical discriminant analysis and genetic distances among the species were calculated to depict intragenus identities and affinities.
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Rahman, M.A.; Saad, M.S.
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Inheritance of yield and yield contributing characters were investigated using generation mean analysis, utilising the means of six basic populations viz., P1, P2, F1, F2, BC1P1 and BC1P2 in four crosses of Vigna sesquipedalis. The analysis reiterated that the importance of dominance (h) gene effects for pod yield/plant and pods/plant as compared to additive (d) gene effects. However, significant and positive additive effects were noticed for pod yield/plant, pods/plant, pod weight and seed weight in different crosses. The three types of gene interactions (additive, dominance and epistasis) were significantly involved for pods/plant in cross KU 7 ×KU 8. Among the digenic epistatic interactions, both additive ×additive (i) and dominance × dominance (l) contributed more for pod yield/plant and pods/plant, however, it varied among the crosses. Populations having earliness can be developed as indicated by reducing dominance effects. Pedigree selection and heterosis breeding is suggested to exploit the fixable and non fixable components of variation respectively in Vigna sesquipedalis.
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Chong, Alexander; Hashim, Roshada; Bin Ali, Ahyaudin
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Based on biochemical assays and electrophoretical methods, the inhibitory effects of three plant meals (soybean meal, wheat meal, winged bean meal) on digestive alkaline proteases of discus were investigated. Casein assays revealed that increasing levels of soybean meal caused a linear inhibitory effect on activity of protease. SDS-PAGE images revealed that trypsin and chymotrypsin were the inhibited enzymes. Soybean showed the lowest inhibition rate followed by wheat meal and raw winged bean. There was a quadratic relationship between wheat meal levels and its inhibition of protease acitivity. The highest inhibitory effect was obtained with the winged bean meal with inhibition of caseinolytic activities ranging from 3.6–98.6%. Results from this study showed the potential of both soybean meal and wheat meal as ingredients for practical diet for discus, while demonstrating the need for further improvement in processing method for winged bean meal.
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Yeoh, K.-A.; Othman, A.; Meon, S.; Abdullah, F.; Ho, C.-L.
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Chitinases are glycosyl hydrolases that cleave the β-1,4-glycosidic linkages between N-acetylglucosamine residues in chitin which is a major component of fungal cell wall. Plant chitinases hydrolyze fungal chitin to chitin oligosaccharides that serve as elicitors of plant defense system against fungal pathogens. However, plants synthesize many chitinase isozymes and some of them are not pathogenesis-related. In this study, three full-length cDNA sequences encoding a putative chitinase (EgChit3-1) and two chitinase-like proteins (EgChit1-1 and EgChit5-1) have been cloned from oil palm (Elaeis guineensis) by polymerase chain reaction (PCR). The abundance of these transcripts in the roots and leaves of oil palm seedlings treated with Ganoderma boninense (a fungal pathogen) or Trichoderma harzianum (an avirulent symbiont), and a combination of both fungi at 3, 6 and 12 weeks post infection were profiled by real time quantitative reverse-transcription (qRT)-PCR. Our findings showed that the gene expression of EgChit3-1 increased significantly in the roots of oil palm seedlings treated with either G. boninense or T. harzianum and a combination of both; whereas the gene expression of EgChit1-1 in the treated roots of oil palm seedlings was not significantly higher compared to those of the untreated oil palm roots. The gene expression of EgChit5-1 was only higher in the roots of oil palm seedlings treated with T. harzianum compared to those of the untreated oil palm roots. In addition, the gene expression of EgChit1-1 and EgChit3-1 showed a significantly higher gene expression in the leaf samples of oil palm seedlings treated with either G. boninense or T. harzianum.
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