The molecular composition of the cell wall is critical for the biology and ecology of each fungal species. Fungal walls are composed of matrix components that are embedded and linked to scaffolds of ...fibrous load-bearing polysaccharides. Most of the major cell wall components of fungal pathogens are not represented in humans, other mammals, or plants, and therefore the immune systems of animals and plants have evolved to recognize many of the conserved elements of fungal walls. For similar reasons the enzymes that assemble fungal cell wall components are excellent targets for antifungal chemotherapies and fungicides. However, for fungal pathogens, the cell wall is often disguised since key signature molecules for immune recognition are sometimes masked by immunologically inert molecules. Cell wall damage leads to the activation of sophisticated fail-safe mechanisms that shore up and repair walls to avoid catastrophic breaching of the integrity of the surface. The frontiers of research on fungal cell walls are moving from a descriptive phase defining the underlying genes and component parts of fungal walls to more dynamic analyses of how the various components are assembled, cross-linked, and modified in response to environmental signals. This review therefore discusses recent advances in research investigating the composition, synthesis, and regulation of cell walls and how the cell wall is targeted by immune recognition systems and the design of antifungal diagnostics and therapeutics.
The efficacy of the entomopathogenic fungus, Metarhizium anisopliae, was assessed through applying different conidiospore concentrations of a local isolate against third and fifth larval instars of ...the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. The lowest tested concentrations (2 x 10.sup.1, 2 x 10.sup.2, and 2 x 10.sup.3 conidiospores/ml) caused low mortality rates on the tenth day post-treatment (2-14% for L.sub.3 and 0-6% for L.sub.5). The highest concentrations (2 x 10.sup.4 2 x 10.sup.5, 2 x 10.sup.6, and 2 x 10.sup.7 conidiospores/ml) induced (52-90%) mortality rate in L.sub.3 and (50-100%) in L.sub.5 on the seventh day post-treatment. Death of treated larvae started on the fourth day post-treatment with the high concentrations. LC.sub.50 and LC.sub.90 values were calculated. They were higher for L.sub.3 than for L.sub.5.
Pretreatment is a crucial step in the conversion of lignocellulosic biomass to fermentable sugars and biofuels. Compared to thermal/chemical pretreatment, fungal pretreatment reduces the ...recalcitrance of lignocellulosic biomass by lignin-degrading microorganisms and thus potentially provides an environmentally-friendly and energy-efficient pretreatment technology for biofuel production. This paper provides an overview of the current state of fungal pretreatment by white rot fungi for biofuel production. The specific topics discussed are: 1) enzymes involved in biodegradation during the fungal pretreatment; 2) operating parameters governing performance of the fungal pretreatment; 3) the effect of fungal pretreatment on enzymatic hydrolysis and ethanol production; 4) efforts for improving enzymatic hydrolysis and ethanol production through combinations of fungal pretreatment and physical/chemical pretreatment; 5) the treatment of lignocellulosic biomass with lignin-degrading enzymes isolated from fungal pretreatment, with a comparison to fungal pretreatment; 6) modeling, reactor design, and scale-up of solid state fungal pretreatment; and 7) the limitations and future perspective of this technology.
Fungi are considered the primary decomposers of dead plant biomass in terrestrial ecosystems. However, current knowledge regarding the successive changes in fungal communities during litter ...decomposition is limited. Here we explored the development of the fungal community over 24 months of litter decomposition in a temperate forest with dominant Quercus petraea using 454-pyrosequencing of the fungal internal transcribed spacer (ITS) region and cellobiohydrolase I (cbhI) genes, which encode exocellulases, to specifically address cellulose decomposers. To quantify the involvement of phyllosphere fungi in litter decomposition, the fungal communities in live leaves and leaves immediately before abscission were also analysed. The results showed rapid succession of fungi with dramatic changes in the composition of the fungal community. Furthermore, most of the abundant taxa only temporarily dominated in the substrate. Fungal diversity was lowest at leaf senescence, increased until month 4 and did not significantly change during subsequent decomposition. Highly diverse community of phyllosphere fungi inhabits live oak leaves 2 months before abscission, and these phyllosphere taxa comprise a significant share of the fungal community during early decomposition up to the fourth month. Sequences assigned to the Ascomycota showed highest relative abundances in live leaves and during the early stages of decomposition. In contrast, the relative abundance of sequences assigned to the Basidiomycota phylum, particularly basidiomycetous yeasts, increased with time. Although cellulose was available in the litter during all stages of decomposition, the community of cellulolytic fungi changed substantially over time. The results indicate that litter decomposition is a highly complex process mediated by various fungal taxa.
Lignin degradation by microorganisms: A review Atiwesh, Ghada; Parrish, Christopher C.; Banoub, Joseph ...
Biotechnology progress,
March/April 2022, 2022-Mar, 2022-03-00, 20220301, Letnik:
38, Številka:
2
Journal Article
Recenzirano
Lignin is an abundant plant‐based biopolymer that has found applications in a variety of industries from construction to bioethanol production. This recalcitrant branched polymer is naturally ...degraded by many different species of microorganisms, including fungi and bacteria. These microbial lignin degradation mechanisms provide a host of possibilities to overcome the challenges of using harmful chemicals to degrade lignin biowaste in many industries. The classes and mechanisms of different microbial lignin degradation options available in nature form the primary focus of the present review. This review first discusses the chemical building blocks of lignin and the industrial sources and applications of this multifaceted polymer. The review further places emphasis on the degradation of lignin by natural means, discussing in detail the lignin degradation activities of various fungal and bacterial species. The lignin‐degrading enzymes produced by various microbial species, specifically white‐rot fungi, brown‐rot fungi, and bacteria, are described. In the end, possible directions for future lignin biodegradation applications and research investigations have been provided.
Fungi contribute extensively to a wide range of ecosystem processes, including decomposition of organic carbon, deposition of recalcitrant carbon, and transformations of nitrogen and phosphorus. In ...this review, we discuss the current knowledge about physiological and morphological traits of fungi that directly influence these processes, and we describe the functional genes that encode these traits. In addition, we synthesize information from 157 whole fungal genomes in order to determine relationships among selected functional genes within fungal taxa. Ecosystem-related traits varied most at relatively coarse taxonomic levels. For example, we found that the maximum amount of variance for traits associated with carbon mineralization, nitrogen and phosphorus cycling, and stress tolerance could be explained at the levels of order to phylum. Moreover, suites of traits tended to co-occur within taxa. Specifically, the genetic capacities for traits that improve stress tolerance-β-glucan synthesis, trehalose production, and cold-induced RNA helicases-were positively related to one another, and they were more evident in yeasts. Traits that regulate the decomposition of complex organic matter-lignin peroxidases, cellobiohydrolases, and crystalline cellulases-were also positively related, but they were more strongly associated with free-living filamentous fungi. Altogether, these relationships provide evidence for two functional groups: stress tolerators, which may contribute to soil carbon accumulation via the production of recalcitrant compounds; and decomposers, which may reduce soil carbon stocks. It is possible that ecosystem functions, such as soil carbon storage, may be mediated by shifts in the fungal community between stress tolerators and decomposers in response to environmental changes, such as drought and warming.
Fungi are the agents primarily responsible for the transformation of plant-derived carbon in terrestrial ecosystems. However, little is known of their responses to the seasonal changes in resource ...availability in deciduous forests, including photosynthate allocation below ground and seasonal inputs of fresh litter.
Vertical stratification of and seasonal changes in fungal abundance, activity and community composition were investigated in the litter, organic and upper mineral soils of a temperate Quercus petraea forest using ergosterol and extracellular enzyme assays and amplicon 454-pyrosequencing of the rDNA-ITS region.
Fungal activity, biomass and diversity decreased substantially with soil depth. The highest enzyme activities were detected in winter, especially in litter, where these activities were followed by a peak in fungal biomass during spring. The litter community exhibited more profound seasonal changes than did the community in the deeper horizons. In the litter, saprotrophic genera reached their seasonal maxima in autumn, but summer typically saw the highest abundance of ectomycorrhizal taxa. Although the composition of the litter community changes over the course of the year, the mineral soil shows changes in biomass.
The fungal community is affected by season. Litter decomposition and phytosynthate allocation represent important factors contributing to the observed variations.
Revealing the relationship between plants and fungi is very important in understanding biodiversity maintenance, community stability, and ecosystem functioning. However, differences in the community ...and network structures of phyllosphere epiphytic and endophytic fungi are currently poorly documented. In this study, we examined epiphytic and endophytic fungal communities associated with the leaves of six mangrove species using Illumina MiSeq sequencing of internal transcribed spacer 2 (ITS2) sequences.
A total of 635 operational taxonomic units (OTUs) of endophytic and epiphytic fungi were obtained at a 97% sequence similarity level; they were dominated by Dothideomycetes and Tremellomycetes. Plant identity had a significant effect on the OTU richness of endophytic fungi, but not on epiphytic fungi. The community composition of epiphytic and endophytic fungi was significantly different, and plant identity had a greater effect on endophytic fungi than on epiphytic fungi. Network analysis showed that both epiphytic and endophytic network structures were characterized by significantly highly specialized and modular but lowly connected and anti-nested properties. Furthermore, the endophytic network had higher levels of specialization and modularity but lower connectance and stronger anti-nestedness than the epiphytic network.
This study reveals that the phyllosphere epiphytic and endophytic fungal communities differ, and plant identity has a greater effect on the endophytic fungi than on epiphytic fungi. These findings demonstrate the role of host plant identity in driving phyllosphere epiphytic and endophytic community structure.
Intoxikation durch Pilze (Fungi) Zulauf, N; Oremek, G M; Braun, M ...
Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Ergonomie,
01/2019, Letnik:
69, Številka:
4
Journal Article
Recenzirano
Auch heutzutage sind Pilzintoxikationen mit schwerwiegenden Krankheitsfolgen ein bedeutendes Thema, sogar mit steigender Tendenz in den letzten Jahren. Nachfolgend sollen die Häufigkeit, die Symptome ...und gesundheitliche Komplikationen sowie mögliche Therapie- und auch Präventionsmaßnahmen im Falle einer Exposition mit dem Kartoffel- bzw. Hartbovist als einem wichtigen Vertreter der Giftpilze dargestellt werden. Er stammt aus der Familie der Kartoffelbovistverwandten (Sclerodermataceae) und umfasst weltweit etwa 30 Arten. Von Juni bis Oktober kommt er als Mykorrhizabildner mit verschieden Laub- und Nadelbäumen vor. Aufgrund seiner Toxizität verursacht der Kartoffelbovist Verdauungsstörungen sowie Ohnmacht und Schwindel.
Objective The purpose of the study is to clarify the carrying rates and the differences of fungi associated with four Tomicus species in Yunnan, China and understand the relationships between the ...beetles and these fungi during Tomicus attacking process.Method Fungal carrying rate was analyzed by detecting stained phloem based on artificial inoculation and field survey.Result The fungal carrying rate of Tomicus yunnanensis (80%) was distinctly higher than that of the other three Tomicus species:T. minor (63%), T. armandii (56%), and T. brevipilosus (53%); the fungal carrying rate of Tomicus-larva (90%) was higher than its pupae (78%) and new adult (58%); No significant difference in fungal carrying rate was observed among heads (33%), wings (32%) and legs (30%) of Tomicus-adults. According to field survey, the associated fungi significantly improved the breeding success rate of Tomicus on the trunk.Conclusion This is the first report on the carrying rates and the differences of fungi associated with fo
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