Global diversity and distribution of nitrogen-fixing bacteria in the soil

Our knowledge of microbial biogeography has advanced in recent years, yet we lack knowledge of the global diversity of some important functional groups. Here, we used environmental DNA from 327 globally collected soil samples to investigate the biodiversity patterns of nitrogen-fixing bacteria by focusing on the nifH gene but also amplifying the general prokaryotic 16S SSU region. Globally, N-fixing prokaryotic communities are driven mainly by climatic conditions, with most groups being positively correlated with stable hot or seasonally humid climates. Among soil parameters, pH, but also soil N content were most often shown to correlate with the diversity of N-fixer groups. However, specific groups of N-fixing prokaryotes show contrasting responses to the same variables, notably in Cyanobacteria that were negatively correlated with stable hot climates, and showed a U-shaped correlation with soil pH, contrary to other N-fixers. Also, the non-N-fixing prokaryotic community composition was differentially correlated with the diversity and abundance of N-fixer groups, showing the often-neglected impact of biotic interactions among bacteria

Characterization and development of tropical gasteromycete fungi in ectomycorrhizal associations

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Molecular phylogeny and re-assessment of some Scleroderma spp. (Gasteromycetes)

9 pages, 3 figures, 1 table.[EN] The fungal genus Scleroderma is cosmopolitan in temperate and tropical regions and forms ectomycorrhizal associations with a wide range of forest trees. To delimit phylogenetic Scleroderma species and identification, 43 basidiomes were chosen of different geographical origins and their rDNA internal transcribed spacer (ITS) were sequenced. Phylogenetic analyses of these sequences together with additional GenBank sequences identified 11 taxa. A strong phylogenetic pattern was observed related to a character of their basidiospore ornamentation.[ES] Las especies del género Scleroderma son cosmopolitas y forman ectomicorrizas con un amplio rango de hospedantes, tanto de zonas templadas como tropicales. Para delimitar las especies filogenéticas y la identificación de las mismas, se han seleccionado 43 basidiomas, de diferente origen geográfico, y se han secuenciado las regiones de transcripción interna del ADN ribosómico nuclear. Los análisis filogenéticos de estas colecciones, junto con secuencias obtenidas del GenBank, permiten identificar 11 especies, agrupadas en tres clados relacionados con el tipo de ornamentación de la basidióspora.CP is indebted to the Commission on Higher Education of Thailand, Royal Thai government for financial support and to the European Commission Human Potential Programme for supporting part of this study at the Real Jardín Botánico de Madrid (BIODIBERIA).Peer reviewe

The role of mycorrhizas in more sustainable oil palm cultivation

Oil palm is a significant and developing crop in many developing countries. The introduction of oil palm puts pressure on natural resources because it is often planted in cleared-cut land that previously supported other crops or was forested. This has led to environmental concerns which require attention. Hence it is important that new plantations are managed in a sustainable way to reduce the impact of oil palm cultivation on ecosystems whilst maximising yield and productivity to farmers. The application of arbuscular mycorrhizal fungi (AMF) technology is one option that can benefit both agronomic plant health and ecosystems. AMF have the potential to increase conventional agricultural productivity and are crucial for the sustainable functioning of agricultural ecosystems. This paper provides an insight into how AMF application might benefit oil palm cultivation through more sustainable management and the practical use of AMF for oil palm plantations

High Potential Decolourisation of Textile Dyes from Wastewater by Manganese Peroxidase Production of Newly Immobilised Trametes hirsuta PW17-41 and FTIR Analysis

Coloured wastewater from the textile industry is a very serious global problem. Among 16 different white-rot fungal isolates, Trametes hirsuta PW17-41 revealed high potential for decolourisation of mixed textile dyes (Navy EC-R, Ruby S3B and Super Black G) from real industrial wastewater samples. The efficiency of dye decolourisation was evaluated using the American Dye Manufacturers’ Institute (ADMI) standard methodology. The suitable support for fungal mycelium immobilisation was nylon sponges. The optimal dye decolourisation (95.39%) was achieved by using palm sugar and ammonium nitrate as carbon and nitrogen sources, respectively. The initial pH was 5 and the agitation speed was 100 rpm at 30 °C. The ADMI values of textile dyes decreased from 2475 to 114 within two days, reducing the treatment time from seven days before optimisation. The major mechanism of dye decolourisation was biodegradation, which was confirmed by UV–visible and FTIR spectra. Manganese peroxidase (MnP) (4942 U L−1) was found to be the main enzyme during the decolourisation process at an initial dye concentration of 21,200 ADMI. The results indicated the strong potential of immobilised fungal cells to remove high concentrations of textile dyes from industrial wastewater and their potential ability to produce high MnP and laccase activities that can be used in further application

Maximum likelihood tree from ITS dataset identifies <i>Astraeus sirindhorniae</i> as a distinct species of <i>Astraeus</i>.

<p>Numbers above branches identify the statistics bootstrap percentages (bold text, before forward slash) and Bayesian posterior probabilities (normal text, after forward slash) for that branch. Maximum likelihood bootstraps from 1000 iterations. Bayesian posterior probabilities from 1000 iterations (1 million runs sampling every 1000^th iteration).</p

Astraodoric Acids A–D: New Lanostane Triterpenes from Edible Mushroom <i>Astraeus odoratus</i> and Their Anti-<i>Mycobacterium tuberculosis</i> H₃₇Ra and Cytotoxic Activity

Tuberculosis (TB) is one of the chronic infectious diseases caused by <i>Mycobacterium tuberculosis</i> that causes about 2–3 million deaths per year. Isoniazid and rifampicin are examples of first line drugs used for TB treatment; however, they are potentially hepatotoxic. More effective and safer drugs are urgently needed, especially from natural products. Basidiomycete mushrooms are known as important sources of pharmaceutically active metabolites including an anti-TB agent. In this work, the chemical constituents of the edible mushroom <i>Astraeus odoratus</i> were isolated and investigated for antibacterial activity against <i>M. tuberculosis</i> H₃₇Ra. The cytotoxic activity against cancerous cell lines was also evaluated. Four new lanostane triterpenes, astraodoric acids A–D, and new 5-hydroxyhypaphorine have been isolated together with four known compounds. The structures were elucidated by NMR spectroscopic methods, HR-ESI-MS results, and X-ray crystallographic analysis. Astraodoric acids A and B exhibited moderate antibacterial (MICs of 50 and 25 μg/mL) and cytotoxic activities (IC₅₀ values of 34.69 and 18.57 μg/mL against KB and 19.99 and 48.35 μg/mL against NCI-H187), respectively. The results of this study show that <i>A. odoratus</i> could be a significant natural source for safer antitubercular and anticancer agents

<i>Astraeus sirindhorniae</i>.

<p>Exoperidium layers (A–B). (A) exoperidial subpellis, bar = 5 µm. (B) exoperidial subpellis (innermost), bar = 10 µm. (C) rhizomorph hyphae with clamp connection (arrowhead), bar = 5 µm. (D) capillitium hyphae displaying continuous lumen (arrowhead) and basidiospore (arrow), bar = 5 µm. (E–F) spore ornamentation demonstrated coalescent spines in groups, bar = 1 µm. A–D magnification at 1,000×.</p

Maximum likelihood tree from a multigene dataset reveals the placement of <i>Astraeus sirindhorniae</i> within the Sclerodermatineae.

<p>Thick vertical black bars identify root branch for the taxonomic lineage indicated by the adjacent label. Numbers above branches identify the statistics bootstrap percentages (bold text, before forward slash) and Bayesian posterior probabilities (normal text, after forward slash) for that branch. Maximum likelihood bootstraps from 1000 iterations. Bayesian posterior probabilities from 1000 iterations (1 million runs sampling every 1000^th iteration).</p