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.

Background

European forests are considered a crucial resource for supplying biomass to a growing bio-economy in Europe. This study aimed to assess the potential availability of forest biomass from European forests and its spatial distribution. We tried to answer the questions (i) how is the potential forest biomass availability spatially distributed across Europe and (ii) where are hotspots of potential forest biomass availability located?

Methods

The spatial distribution of woody biomass potentials was assessed for 2020 for stemwood, residues (branches and harvest losses) and stumps for 39 European countries. Using the European Forest Information SCENario (EFISCEN) model and international forest statistics, we estimated the theoretical amount of biomass that could be available based on the current and future development of the forest age-structure, growing stock and increment and forest management regimes. We combined these estimates with a set of environmental (site productivity, soil and water protection and biodiversity protection) and technical (recovery rate, soil bearing capacity) constraints, which reduced the amount of woody biomass that could potentially be available. We mapped the potential biomass availability at the level of administrative units and at the 10 km × 10 km grid level to gain insight into the spatial distribution of the woody biomass potentials.

Results

According to our results, the total availability of forest biomass ranges between 357 and 551 Tg dry matter per year. The largest potential supply of woody biomass per unit of land can be found in northern Europe (southern Finland and Sweden, Estonia and Latvia), central Europe (Austria, Czech Republic, and southern Germany), Slovenia, southwest France and Portugal. However, large parts of these potentials are already used to produce materials and energy. The distribution of biomass potentials that are currently unused only partially coincides with regions that currently have high levels of wood production.

Conclusions

Our study shows how the forest biomass potentials are spatially distributed across the European continent, thereby providing insight into where policies could focus on an increase of the supply of woody biomass from forests. Future research on potential biomass availability from European forests should also consider to what extent forest owners would be willing to mobilise additional biomass from their forests and at what costs the estimated potentials could be mobilised.

Background

Fire responses of species in arid environments have only been scarcely studied. We studied four species (Dasyliron lucidum Zucc., Juniperus deppeana Steud., Echinocactus platyacanthus Link & Otto, and Agave potatorum Zucc.) in the Tehuacán-Cuicatlán Biosphere Reserve, Mexico. The objectives were to describe and quantify survival and resprouting, as well as the factors determining them, for the selected species. Six months after a 330 ha wildfire in 2014, 32 plots were established on three transects. Forest dasometric and fire severity variables were recorded. Logistic regression was utilized to obtain mortality and resprouting probability models, as well as linear regression to detect relationships among post- and pre-fire variables.

Results

All species had high survival rates (74.5 to 97.7%). All surviving D. lucidum individuals resprouted apically. For J. deppeana, the probability of mortality was directly related to fire scar height on the trunk and inversely related to its diameter, whereas the probability of crown recovery was inversely related to the proportion of the tree height scorch. For E. platyacanthus, necrosed height was directly related to plant height. There was a positive relationship between basal area and the emission of new leaves for the A. potatorum.

Conclusions

In the different species, several traits that allowed high fire survival rates were observed (e.g., thick cortex or bark, fleshy non-flammable leaves, flammable leaves that reduce fire intensity, high volume to surface ratio). Many of these were primarily linked to drought resistance. All species gain fire resistance or tolerance as they increase in size. We concluded that the studied arid ecosystem of Mexico can withstand an altered or a base fire regime.

Interferon regulatory factors (IRFs) are transcription factors of the interferon (IFN)-inducible signaling pathway essential for host immunity against antimicrobial infection by virus and bacteria. Interferon regulatory factor 3 (IRF3) regulates the expression of IFNs and IFN-stimulated genes by binding to the IFN stimulatory response element (ISRE). In this study, we analyze the thymus transcriptome of the mandarin fish Siniperca chuatsi and report the functional analysis of Irf3 from the thymus as an emerging model of antiviral approaches. The predicted S. chuatsi IRF3 (Sc-Irf3) protein has 465 amino acid residues and evolutionarily conserved domains and is clustered in the IRF3 subfamily on a phylogenetic tree. Sc-Irf3 upon transgenic expression was mainly found in the cytoplasm through Western blot analysis and microscopy, but it translocated to the nucleus after polyinosinic:polycytidylic acid (ploly I:C) treatment. Endogenous Sc-irf3 RNA expression was detected in all eight adult organs examined. Importantly, Sc-irf3 RNA expression was significantly upregulated by ploly(I:C) treatment in the adult organs. Concurrently, reporter assays revealed that Sc-Irf3 increased the transcriptional activity of the ifnβ promoter, a minimal ISRE-containing promoter, and ifn promoter of mandarin fish. Therefore, Sc-Irf3 plays a major role in the IFN immune defense system against virus infection.

The vast majority of bacteria, including human pathogens and microbiome species, lack genetic tools needed to systematically associate genes with phenotypes. This is the major impediment to understanding the fundamental contributions of genes and gene networks to bacterial physiology and human health. Clustered regularly interspaced short palindromic repeats interference (CRISPRi), a versatile method of blocking gene expression using a catalytically inactive Cas9 protein (dCas9) and programmable single guide RNAs, has emerged as a powerful genetic tool to dissect the functions of essential and non-essential genes in species ranging from bacteria to humans^1–6. However, the difficulty of establishing effective CRISPRi systems across bacteria is a major barrier to its widespread use to dissect bacterial gene function. Here, we establish ‘Mobile-CRISPRi’, a suite of CRISPRi systems that combines modularity, stable genomic integration and ease of transfer to diverse bacteria by conjugation. Focusing predominantly on human pathogens associated with antibiotic resistance, we demonstrate the efficacy of Mobile-CRISPRi in gammaproteobacteria and Bacillales Firmicutes at the individual gene scale, by examining drug–gene synergies, and at the library scale, by systematically phenotyping conditionally essential genes involved in amino acid biosynthesis. Mobile-CRISPRi enables genetic dissection of non-model bacteria, facilitating analyses of microbiome function, antibiotic resistances and sensitivities, and comprehensive screens for host–microorganism interactions.

Bryozoan records from the shores and upper shelf (≤50 m depth) of the remote Azores Archipelago (central North Atlantic) have been analyzed, along with unpublished data and data from recent surveys. A checklist of 67 shallow-water species is hereby compiled for the region, of which more than one third represent records from campaigns conducted during the last 20 years. A classification on the origin of the species indicates that the majority (62%) are cryptogenic while 27% (n = 18) are considered native. Given the natural limitations for genetic exchange between the archipelago’s bryozoan populations and those from neighboring shores, the taxa presently considered as cryptogenic may yield a considerable amount of endemic species after taxonomic revision. The remaining 11% are confirmed as non-indigenous species, highlighting the importance of human-mediated transport in considerably enhancing the diversity of bryozoans in remote oceanic archipelagos, which would otherwise be off-limits to their natural dispersal capacity. In view of the need to quantitatively evaluate the certainty of species-level identification when assembling such biodiversity inventories, we have developed a method to attribute a degree of certainty to species records. The application of this method to the current checklist highlights the importance of further studies to ascertain the identification of many species recorded for the Azores, and to be able to categorize them confidently as either native, cryptogenic or non-indigenous.

The available published data and materials from our own research into 14 mineral and 19 thermal springs of the Lake Baikal Region performed in 1997–2017 are summarized. Soil profiles have been laid and samples of water, algae, lichens, mosses, and vascular plants and qualitative and quantitative specimens of zoobenthos have been taken. The profile of soils in the area of springs is short and their chemical composition corresponds to that of water; they are called parasoils. We reveal 257 species of algae in the mineral springs, and most of them (196 species) are assigned to the diatoms. The lichen flora is nonspecific. Seven species are found in the mineral springs, and 100 lower taxa are sampled around the thermal springs. Six types of communities of zoobenthos are specified in the mineral sodium chloride springs according to the group of macroinvertebrates, dominating in biomass: Gastropoda-like, Turbellaria-like, Chironomidae-like, Amphipoda-like, Psychodidae-like, and Ephydridae-like. In the thermal springs, four types of communities of zoobenthos are recognized: Gastropoda-like (with the specification into mono-, two- and three-dominant), Odonata-like, Amphipoda-like, and Chironomidae-like. The thermal springs are mainly characterized by high biomass typical for eutrophic and hypertrophic lakes. The species status of mollusk Lymnaea thermobaicalica—endemic to high-thermal springs—is confirmed.