The invertebrate phylum Tardigrada has received much attention for containing species adapted to the most challenging environmental conditions where an ability to survive complete desiccation or freezing in a cryptobiotic state is necessary for persistence. Although research on tardigrades has a long history, the last decade has seen a dramatic increase in molecular biological (“omics”) studies, most of them with the aim to reveal the biochemical mechanisms behind desiccation tolerance of tardigrades. Several other aspects of tardigrade cell biology have been studied, and we review some of them, including karyology, embryology, the role of storage cells, and the question of whether tardigrades are eutelic animals. We also review some of the theories about how anhydrobiotic organisms are able to maintain cell integrity under dry conditions, and our current knowledge on the role of vitrification and DNA protection and repair. Many aspects of tardigrade stress tolerance have relevance for human medicine, and the first transfers of tardigrade stress genes to human cells have now appeared. We expect this field to develop rapidly in the coming years, as more genomic information becomes available. However, many basic cell biological aspects remain to be investigated, such as immunology, cell cycle kinetics, cell metabolism, and culturing of tardigrade cells. Such development will be necessary to allow tardigrades to move from a nonmodel organism position to a true model organism with interesting associations with the current models C. elegans and D. melanogaster.

To comprehensively evaluate the relationship between high iodine concentration and biomarker abnormalities related to autoimmune thyroiditis in a Chinese population. Medline, PubMed, and Embase electronic databases were searched for articles published domestically and internationally on the relationship between high iodine concentrations and thyroid hormone antibodies and thyroid-stimulating hormone in China before March 2019. Articles published in Chinese were searched in the China Biology Medicine (CBM) disc, Wanfang Database, and China National Knowledge Infrastructure (CNKI). A total of 16 cross-sectional articles were included in this study, including 9061 participants. A meta-analysis was conducted in Stata 14.0. The binary categorical and continuous variables used odds ratios (ORs) and standardized mean differences (SMDs) with the corresponding 95% confidence intervals (CIs) as the effect statistics, respectively. The results showed that high iodine concentrations had a minimal association with the abnormal rates of thyroid peroxidase antibody (TPOAb) (OR = 1.274, 95% CI (0.957, 1.695), P > 0.05) and thyroglobulin antibody (TGAb) (OR = 1.217, 95% CI (0.911, 1.626), P > 0.05) in the entire population. The thyroid-stimulating hormone (TSH) level in the high iodine group was greater than that in the adaptive iodine group (SMD = 0.202, 95% CI (0.096, 0.309), P < 0.05). The results of the subgroup analysis showed that the abnormal TPOAb rate in pregnant women (OR = 1.519, 95% CI (1.007, 2.291), P < 0.05) and children (OR = 3.365, 95% CI (1.966, 5.672), P < 0.05) in the high iodine group was greater than that in the adaptive iodine group, and the abnormal TGAb rate of children in the high iodine group was greater than that in the adaptive iodine group. The TSH levels of lactating women (SMD = 0.24, 95% CI (0.053, 0.427), P < 0.05), pregnant women (SMD = 0.301, 95% CI (0.176, 0.426), P < 0.05), and children (SMD = 0.25, 95% CI(0.096, 0.309), P < 0.05) in the high iodine group were higher than those in the adaptive iodine group. Egger’s and Begg’s tests showed no significant (P > 0.1) publication bias. High iodine can increase the risk of abnormal levels of TPOAb, TGAb, and TSH related to autoimmune thyroiditis in pregnant women, lactating women, and children in China.

In this study, a steam gasification with a dual fluidized bed reactor is constructed using a commercial process simulator and validated by experimental data to investigate the behaviors of raw and torrefied spruce wood during the conversion process. Effects of torrefaction, gasification temperature, and steam-to-biomass ratio on the performance of spruce gasification are examined. Main gasification indicators including product gas composition and heating value as well as cold gas efficiency are investigated. Simulation results show that both the H₂ and CO₂ contents in the product gas are reduced with increasing the gasification temperature or decreasing the steam-to-biomass ratio. On the other hand, the CO content shows an opposite trend. In addition, increasing the gasification temperature or decreasing the steam-to-biomass ratio enhances the heating value of the product gas but reduces the cold gas efficiency. Compared with the raw feedstock, the torrefied spruce offers lower H₂ but higher CO content in the product gas at the same gasification condition. Nevertheless, gasification of the torrefied spruce always results in higher cold gas heating value and efficiency than that of the raw spruce. The increased values are up to 0.46 MJ/Nm³ for the heating value and 5.96% for the efficiency.

Extracts of leaf from five native Chilean weeds were evaluated in the biosynthesis of silver nanoparticles. The synthesis was monitored by UV-Vis spectra at 420 nm by typical formation of surface plasmon resonance. Moreover, the extract with major potential for the formation of nanoparticles was used to optimize the synthesis processes by response surface methodology, to obtain nanoparticles of small sizes by combination of three parameters (AgNO₃ and leaf extract concentrations and pH). Characterization of AgNPs was made by TEM, XRD, and DLS. The inhibitory activity was evaluated by disk diffusion method and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Only two out of five extracts evaluated (Hypericum perforatum and Malva nicaensis) showed capacity to biosynthesize AgNPs. pH 10, AgNO₃ (1 mM), and leaf extract at 5% vv⁻¹ were the optimal conditions to synthesize small AgNPs (< 40 nm). Inhibition zone from diffusion disk assay, MIC (30 μg mL⁻¹) and MBC (40 μg mL⁻¹), revealed a high antibacterial activity of AgNPs against Ralstonia solanacearum. Based on the results, the AgNPs biosynthesized from the leaf extract of H. perforatum is a promising antibacterial agent for its use in the control of R. solanacearum.

Considering the great lethality and sequels caused by meningitis, rapid diagnosis and prompt treatment initiation have a great impact on patient outcome. Here, we developed a multiplex-PCR for simultaneous detection of the four most prevalent bacterial pathogens directly in CSF samples. The multiplex-PCR was designed to detect the following genes: fbsA (Streptococcus agalactiae), lytA (Streptococcus pneumoniae), crtA (Neisseria meningitidis), p6 (Haemophilus influenzae), and 16S rRNA (any bacterial agent). The multiplex-PCR showed a DNA detection limit of 1 pg/μL. Among 447 CSF samples tested, 40 were multiplex-PCR positive, in which 27 and 13 had positive and negative bacterial culture, respectively. Our multiplex-PCR is fast, reliable, and easily implementable into a laboratory routine for bacterial meningitis confirmation, especially for patients who previously started antimicrobial therapy. Our molecular approach can substantially improve clinical diagnosis and epidemiological measures of meningitis disease burden.

This correction stands to correct the erroneous corresponding author name Rabson Chiza Chikoti. The publisher and everyone involved would like readers to know that the correct name credited should be Patrick Chiza Chikoti and not the former. The original article has been corrected.

Summary

Misidentification of taxa is understudied but has the potential to be a highly problematic issue. If misidentification is prevalent, there could be significant ramifications for work which relies upon a reliable taxonomic base, such as the description of new species, estimating the size of populations and species prioritisation. Here we used a match-mismatch experiment from psychology to determine the accuracy of species identification in 20 pairs of orchids (Angraecum spp. from Madagascar). The participants were split into specialist taxonomists and non-taxonomists. There was a 57.2% accuracy across all the participants. The specialist taxonomists had a high accuracy of 80.0%, with a sensitivity analysis producing an upper accuracy estimate of 90.7%. Non-taxonomists had a much lower accuracy of 55.9%. The results provide evidence of the need for specialist taxonomists, particularly in the case of identifying Malagasy orchids. Nevertheless, since misidentification is still prevalent for specialists, this is an issue that requires further research to understand how accurate identifications are made and also the implications of errors.

Background

The genus Ilex (Aquifoliaceae) has a near-cosmopolitan distribution in mesic habitats from tropical to temperate lowlands and in alpine forests. It has a high rate of hybridization and plastid capture, and comprises four geographically structured plastid groups. A previous study showed that the plastid rbcL gene, coding for the large subunit of Rubisco, has a particularly high rate of non-synonymous substitutions in Ilex, when compared with other plant lineages. This suggests a strong positive selection on rbcL, involved in yet unknown adaptations. We therefore investigated positive selection on rbcL in 240 Ilex sequences from across the global range.

Results

The rbcL gene shows a much higher rate of positive selection in Ilex than in any other plant lineage studied so far (> 3000 species) by tests in both PAML and SLR. Most positively selected residues are on the surface of the folded large subunit, suggesting interaction with other subunits and associated chaperones, and coevolution between positively selected residues is prevalent, indicating compensatory mutations to recover molecular stability. Coevolution between positively selected sites to restore global stability is common.

Conclusions

This study has confirmed the predicted high incidence of positively selected residues in rbcL in Ilex, and shown that this is higher than in any other plant lineage studied so far. The causes and consequences of this high incidence are unclear, but it is probably associated with the similarly high incidence of hybridization and introgression in Ilex, even between distantly related lineages, resulting in large cytonuclear discordance in the phylogenies.

Mitochondria-targeted antioxidants (also known as ‘Skulachev Ions’ electrophoretically accumulated by mitochondria) exert anti-ageing and ROS-protecting effects well documented in animal and human cells. However, their effects on chloroplast in photosynthetic cells and corresponding mechanisms are scarcely known. For the first time, we describe a dramatic quenching effect of (10-(6-plastoquinonyl)decyl triphenylphosphonium (SkQ1) on chlorophyll fluorescence, apparently mediated by redox interaction of SkQ1 with Mn cluster in Photosystem II (PSII) of chlorophyte microalga Chlorella vulgaris and disabling the oxygen-evolving complex (OEC). Microalgal cells displayed a vigorous uptake of SkQ1 which internal concentration built up to a very high level. Using optical and EPR spectroscopy, as well as electron donors and in silico molecular simulation techniques, we found that SkQ1 molecule can interact with Mn atoms of the OEC in PSII. This stops water splitting giving rise to potent quencher(s), e.g. oxidized reaction centre of PSII. Other components of the photosynthetic apparatus proved to be mostly intact. This effect of the Skulachev ions might help to develop in vivo models of photosynthetic cells with impaired OEC function but essentially intact otherwise. The observed phenomenon suggests that SkQ1 can be applied to study stress-induced damages to OEC in photosynthetic organisms.

Gossypol is a toxic polyphenolic product that is derived from cotton plants. The toxicity of gossypol has limited the utilization of cottonseed meal (CSM) in the feed industry. The gene, Helicoverpa armigera CYP9A12, is a gossypol-inducible cytochrome P450 gene. The objective of our study was to obtain the functional recombinant H. armigera CYP9A12 enzyme in Pichia pastoris and to verify whether this candidate enzyme could decrease gossypol in vitro. Free and total gossypol contents were detected in the enzyme solution and in CSM. The H. armigera CYP9A12 enzyme degraded free concentration of gossypol. After optimization of the single-test and response surface method, free gossypol content could be decreased to 40.91 mg/kg in CSM by the H. armigera CYP9A12 enzyme when the initial temperature was 35 °C, the enzymatic hydrolysis time lasted 2.5 h, the enzyme addition was 2.5 mL, and the substrate moisture was 39%.