25 research outputs found
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<sup>th</sup> iteration).</p
Astraodoric Acids A–D: New Lanostane Triterpenes from Edible Mushroom <i>Astraeus odoratus</i> and Their Anti-<i>Mycobacterium tuberculosis</i> H<sub>37</sub>Ra 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> H<sub>37</sub>Ra.
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 (IC<sub>50</sub> 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
Selection of White-Rot Fungi for Decolorization of Palm Oil Mill Effluent and Evaluation of Biodegradation and Biosorption Processes
Ten species of white-rot fungi were evaluated for their ability to decolorization of palm oil mill effluent. The highest decolorization efficiency was found with Trametes elegans (PP17-06), followed by Ganoderma sp.2 (PW17-06) and Ganoderma sp.2 (PW17-177), respectively. T. elegans was further evaluated for the long-term performance of decolorization for 24 d. The optimal retention time for the decolorization was 8 d, with a color removal efficiency of 47.7%. Beyond 18 d of incubation, decolorization efficiency was reduced due to the autolysis of enzymes. During the biodegradation process, manganese peroxidase enzyme activities reached a maximum of 36.03 U.L−1. However, no significant laccase and lignin peroxidase activities were observed. T. elegans was also assessed for decolorization performance through biosorption on mycelial biomass. The synthesis of the enzyme was prevented by exposing the mycelium to HgCl2. Within an optimal contact time of 2 d, decolorization efficiency reached 12.5% with ADMI reduction from 4259.0 (±20.1) ADMI to 3727 (±104.04) ADMI. Results indicate that the adsorption capacity was reached at this time, and no significant color removal can be achieved by biomass. Results obtained in this study showed the potential of T. elegans in decolorizing palm oil mill effluent