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1.
Microb Ecol ; 78(3): 725-736, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30761423

RESUMEN

The home-field advantage (HFA) hypothesis has been used intensively to study leaf litter decomposition in various ecosystems. However, the HFA in woody substrates is still unexplored. Here, we reanalyzed and integrated existing datasets on various groups of microorganisms collected from natural deadwood of two temperate trees, Fagus sylvatica and Picea abies, from forests in which one or other of these species dominates but where both are present. Our aims were (i) to test the HFA hypothesis on wood decomposition rates of these two temperate tree species, and (ii) to investigate if HFA hypothesis can be explained by diversity and community composition of bacteria and in detail N-fixing bacteria (as determined by molecular 16S rRNA and nifH gene amplification) and fungi (as determined by molecular ITS rRNA amplification and sporocarp surveys). Our results showed that wood decomposition rates were accelerated at "home" versus "away" by 38.19% ± 20.04% (mean ± SE). We detected strong changes in fungal richness (increase 36-50%) and community composition (RANOSIM = 0.52-0.60, P < 0.05) according to HFA hypothesis. The changes of fungi were much stronger than for total bacteria and nitrogen fixing for both at richness and community composition levels. In conclusion, our results support the HFA hypothesis in deadwood: decomposition rate is accelerated at home due to specialization of fungal communities produced by the plant community above them. Furthermore, the higher richness of fungal sporocarps and nitrogen-fixing bacteria (nifH) may stimulate or at least stabilize wood decomposition rates at "home" versus "away."


Asunto(s)
Fagus/microbiología , Hongos/aislamiento & purificación , Hongos/metabolismo , Micobioma , Picea/microbiología , Madera/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodegradación Ambiental , ADN de Hongos/genética , Hongos/clasificación , Hongos/genética , Nitrógeno/metabolismo , ARN Ribosómico 16S/genética , Árboles/microbiología
2.
Conserv Biol ; 33(3): 716-724, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30350883

RESUMEN

Next-generation sequencing (NGS) has significantly increased knowledge of microbial communities and their distribution. However, it is still not common to apply NGS technology to microbial conservation. We sought to use NGS technologies to evaluate conservation strategies for wood-inhabiting fungi. Evaluating a deadwood experiment 3 years after it was established, we specifically examined which tree species combinations promoted the highest richness of wood-inhabiting fungi. Deadwood enrichment was an effective strategy and logs of 6 tree species, either those with the highest wood-inhabiting fungal α and γ diversity or those with the highest ß diversity, maintained >1,000 operational taxonomic units (OTUs) spread over a wide range of taxonomic groups. In comparison, a conservation strategy based only on the results of sporocarp surveys yielded 591 OTUs. This result highlights the need to use NGS approaches to inform microbial conservation strategies. We also determined that 5 tree species with the highest saproxylic beetle γ diversity simultaneously conserved wood-inhabiting fungi. Apart from deadwood volume, we suggest data on deadwood quality and species also be included as indicators, especially for wood-inhabiting fungal diversity, and incorporated quickly in forest assessment and monitoring systems in Central Europe.


Aplicación de Tecnologías de Secuenciación de Nueva Generación a la Conservación de Hongos Habitantes de Madera Resumen La secuenciación de nueva generación (NGS, en inglés) ha incrementado significativamente el conocimiento que tenemos de las comunidades microbianas y su distribución. Sin embargo, aún no es común aplicar la tecnología NGS a la conservación de microbios. Buscamos usar estas tecnologías para evaluar las estrategias de conservación que hay para los hongos que habitan la madera. Durante la evaluación de un experimento con madera muerta tres años después de que fue establecido, examinamos específicamente cuáles combinaciones de especies de árbol promovían la mayor riqueza de hongos que habitan la madera. El enriquecimiento de madera muerta fue una estrategia efectiva y los troncos de seis especies de árboles, ya fueran aquellas con la diversidad α y la γ más altas de hongos habitantes de madera o aquellas con la diversidad ß más alta, mantuvieron a >1000 unidades taxonómicas operativas (OTUs, en inglés) distribuidas en una gama amplia de grupos taxonómicos. En comparación, una estrategia de conservación basada sólo en los resultados de los censos de esporocarpos dio como resultado 591 OTUs. Este resultado resalta la necesidad de utilizar estrategias de NGS para informar a las estrategias de conservación de microbios. También determinamos que cinco especies de árboles con la diversidad γ más alta de escarabajos saproxílicos conservaron simultáneamente a los hongos que habitan la madera. Además del volumen de madera muerta, sugerimos que también se incluyan como indicadores los datos sobre la calidad de la madera muerta y las especies, especialmente para la diversidad de hongos que habitan la madera, y que se incorpore rápidamente a los sistemas de evaluación y monitoreo de bosques en Europa central.


Asunto(s)
Biodiversidad , Madera , Animales , Conservación de los Recursos Naturales , Europa (Continente) , Hongos , Secuenciación de Nucleótidos de Alto Rendimiento , Árboles
3.
Front Microbiol ; 9: 2120, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30294306

RESUMEN

Despite the important role of wood-inhabiting fungi (WIF) in deadwood decomposition, our knowledge of the factors shaping the dynamics of their species richness and community composition is scarce. This is due to limitations regarding the resolution of classical methods used for characterizing WIF communities and to a lack of well-replicated long-term experiments with sufficient numbers of tree species. Here, we used a large scale experiment with logs of 11 tree species at an early stage of decomposition, distributed across three regions of Germany, to identify the factors shaping WIF community composition and Operational Taxonomic Unit (OTU) richness using next generation sequencing. We found that tree species identity was the most significant factor, corresponding to (P < 0.001) and explaining 10% (representing 48% of the explainable variance) of the overall WIF community composition. The next important group of variables were wood-physicochemical properties, of which wood pH was the only factor that consistently corresponded to WIF community composition. For overall WIF richness patterns, we found that approximately 20% of the total variance was explained by wood N content, location, tree species identity and wood density. It is noteworthy that the importance of determinants of WIF community composition and richness appeared to depend greatly on tree species group (broadleaved vs. coniferous) and it differed between the fungal phyla Ascomycota and Basidiomycota.

4.
Environ Microbiol ; 20(5): 1693-1710, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29473288

RESUMEN

Nitrogen deposition can strongly affect biodiversity, but its specific effects on terrestrial microbial communities and their roles for ecosystem functions and processes are still unclear. Here, we investigated the impacts of N deposition on wood-inhabiting fungi (WIF) and their related ecological functions and processes in a highly N-limited deadwood habitat. Based on high-throughput sequencing, enzymatic activity assay and measurements of wood decomposition rates, we show that N addition has no significant effect on the overall WIF community composition or on related ecosystem functions and processes in this habitat. Nevertheless, we detected several switches in presence/absence (gain/loss) of wood-inhabiting fungal OTUs due to the effect of N addition. The responses of WIF differed from previous studies carried out with fungi living in soil and leaf-litter, which represent less N-limited fungal habitats. Our results suggest that adaptation at different levels of organization and functional redundancy may explain this buffered response and the resistant microbial-mediated ecosystem function and processes against N deposition in highly N-limited habitats.


Asunto(s)
Biodiversidad , Hongos/efectos de los fármacos , Hongos/fisiología , Micobioma , Nitrógeno/farmacología , Madera/microbiología , Aclimatación , Hongos/clasificación , Microbiota , Nitrógeno/análisis , Hojas de la Planta/microbiología , Microbiología del Suelo
5.
ISME J ; 2017 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-29087376

RESUMEN

Wood-inhabiting fungi have essential roles in the regulation of carbon stocks and nutrient cycling in forest ecosystems. However, knowledge pertaining to wood-inhabiting fungi is only fragmentary and controversial. Here we established a large-scale deadwood experiment with 11 tree species to investigate diversity and tree species preferences of wood-inhabiting fungi using next-generation sequencing. Our results contradict existing knowledge based on sporocarp surveys and challenge current views on their distribution and diversity in temperate forests. Analyzing α-, ß- and γ-diversity, we show that diverse fungi colonize deadwood at different spatial scales. Specifically, coniferous species have higher α- and γ-diversity than the majority of analyzed broadleaf species, but two broadleaf species showed the highest ß-diversity. Surprisingly, we found nonrandom co-occurrence (P<0.001) and strong tree species preferences of wood-inhabiting fungi, especially in broadleaf trees (P<0.01). Our results indicate that the saprotrophic fungal community is more specific to tree species than previously thought.The ISME Journal advance online publication, 31 October 2017; doi:10.1038/ismej.2017.177.

6.
BMC Res Notes ; 10(1): 95, 2017 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-28193243

RESUMEN

Since it first launched in 2008, BMC Research Notes has been a place where researchers can publish short notes and observations, research outputs which are useful for the community but which can end up hidden in the lab notebook or as a footnote in a dataset. In order to re-affirm the importance of publishing these kinds of outputs, the journal is renewing its focus on publishing note articles as well as other potentially dark data such as short null results. Publishing these articles is useful for many researchers, therefore we are also expanding the scope to all scientific and clinical disciplines including health sciences, life sciences, physical sciences, mathematics and all engineering disciplines. With this refocusing of BMC Research Notes back to its original vision, BioMed Central is offering a home for short communications to make dark data and single observations widely available to the global research community.


Asunto(s)
Investigación Biomédica/métodos , Políticas Editoriales , Publicaciones Periódicas como Asunto/normas , Proyectos de Investigación
7.
Mol Ecol ; 25(16): 4059-74, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27357176

RESUMEN

Microorganisms play a crucial role in the biological decomposition of plant litter in terrestrial ecosystems. Due to the permanently changing litter quality during decomposition, studies of both fungi and bacteria at a fine taxonomic resolution are required during the whole process. Here we investigated microbial community succession in decomposing leaf litter of temperate beech forest using pyrotag sequencing of the bacterial 16S and the fungal internal transcribed spacer (ITS) rRNA genes. Our results reveal that both communities underwent rapid changes. Proteobacteria, Actinobacteria and Bacteroidetes dominated over the entire study period, but their taxonomic composition and abundances changed markedly among sampling dates. The fungal community also changed dynamically as decomposition progressed, with ascomycete fungi being increasingly replaced by basidiomycetes. We found a consistent and highly significant correlation between bacterial richness and fungal richness (R = 0.76, P < 0.001) and community structure (RM antel  = 0.85, P < 0.001), providing evidence of coupled dynamics in the fungal and bacterial communities. A network analysis highlighted nonrandom co-occurrences among bacterial and fungal taxa as well as a shift in the cross-kingdom co-occurrence pattern of their communities from the early to the later stages of decomposition. During this process, macronutrients, micronutrients, C:N ratio and pH were significantly correlated with the fungal and bacterial communities, while bacterial richness positively correlated with three hydrolytic enzymes important for C, N and P acquisition. Overall, we provide evidence that the complex litter decay is the result of a dynamic cross-kingdom functional succession.


Asunto(s)
Bacterias/clasificación , Bosques , Hongos/clasificación , Hojas de la Planta/microbiología , Microbiología del Suelo , ADN Espaciador Ribosómico/genética , ARN Ribosómico 16S/genética
9.
J Nat Prod ; 79(4): 929-38, 2016 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-26953507

RESUMEN

The Chilean Sepedonium aff. chalcipori strain KSH 883, isolated from the endemic Boletus loyo Philippi, was studied in a polythetic approach based on chemical, molecular, and biological data. A taxonomic study of the strain using molecular data of the ITS, EF1-α, and RPB2 barcoding genes confirmed the position of the isolated strain within the S. chalcipori clade, but also suggested the separation of this clade into three different species. Two new linear 15-residue peptaibols, named chilenopeptins A (1) and B (2), together with the known peptaibols tylopeptins A (3) and B (4) were isolated from the semisolid culture of strain KSH 883. The structures of 1 and 2 were elucidated on the basis of HRESIMS(n) experiments in conjunction with comprehensive 1D and 2D NMR analysis. Thus, the sequence of chilenopeptin A (1) was identified as Ac-Aib(1)-Ser(2)-Trp(3)-Aib(4)-Pro(5)-Leu(6)-Aib(7)-Aib(8)-Gln(9)-Aib(10)-Aib(11)-Gln(12)-Aib(13)-Leu(14)-Pheol(15), while chilenopeptin B (2) differs from 1 by the replacement of Trp(3) by Phe(3). Additionally, the total synthesis of 1 and 2 was accomplished by a solid-phase approach, confirming the absolute configuration of all chiral amino acids as l. Both the chilenopeptins (1 and 2) and tylopeptins (3 and 4) were evaluated for their potential to inhibit the growth of phytopathogenic organisms.


Asunto(s)
Antibacterianos/aislamiento & purificación , Peptaiboles/aislamiento & purificación , Secuencia de Aminoácidos , Antibacterianos/química , Antibacterianos/farmacología , Basidiomycota/metabolismo , Chile , Hypocreales/química , Estructura Molecular , Peptaiboles/química , Peptaiboles/farmacología , Péptidos/química , Péptidos/aislamiento & purificación , Péptidos/farmacología , Trichoderma/química
10.
PLoS One ; 11(2): e0148130, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26840453

RESUMEN

Fungi are prominent drivers of ecological processes in soils, so that fungal communities across different soil ecosystems have been well investigated. However, for arable soils taxonomically resolved fine-scale studies including vertical itemization of fungal communities are still missing. Here, we combined a cloning/Sanger sequencing approach of the ITS/LSU region as marker for general fungi and of the partial SSU region for arbuscular mycorrhizal fungi (AMF) to characterize the microbiome in different maize soil habitats. Four compartments were analyzed over two annual cycles 2009 and 2010: a) ploughed soil in 0-10 cm, b) rooted soil in 40-50 cm, c) root-free soil in 60-70 cm soil depth and d) maize roots. Ascomycota was the most dominant phylum across all compartments. Fungal communities including yeasts and AMF differed strongly between compartments. Inter alia, Tetracladium, the overall largest MOTU (molecular operational taxonomic unit), occurred in all compartments, whereas Trichosporon dominated all soil compartments. Sequences belonging to unclassified Helotiales were forming the most abundant MOTUs exclusively present in roots. This study gives new insights on spatial distribution of fungi and helps to link fungal communities to specific ecological properties such as varying resources, which characterize particular niches of the heterogeneous soil environment.


Asunto(s)
Hongos/fisiología , Microbiota/fisiología , Microbiología del Suelo , Suelo
11.
Bioconjug Chem ; 27(2): 319-28, 2016 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-26172432

RESUMEN

Multimodal nanoparticulate materials are described, offering magnetic, radionuclide, and fluorescent imaging capabilities to exploit the complementary advantages of magnetic resonance imaging (MRI), positron emission tomography/single-photon emission commuted tomography (PET/SPECT), and optical imaging. They comprise Fe3O4@NaYF4 core/shell nanoparticles (NPs) with different cation dopants in the shell or core, including Co0.16Fe2.84O4@NaYF4(Yb, Er) and Fe3O4@NaYF4(Yb, Tm). These NPs are stabilized by bisphosphonate polyethylene glycol conjugates (BP-PEG), and then show a high transverse relaxivity (r2) up to 326 mM(-1) s(-1) at 3T, a high affinity to [(18)F]-fluoride or radiometal-bisphosphonate conjugates (e.g., (64)Cu and (99m)Tc), and fluorescent emissions from 500 to 800 nm under excitation at 980 nm. The biodistribution of intravenously administered particles determined by PET/MR imaging suggests that negatively charged Co0.16Fe2.84O4@NaYF4(Yb, Er)-BP-PEG (10K) NPs cleared from the blood pool more slowly than positively charged NPs Fe3O4@NaYF4(Yb, Tm)-BP-PEG (2K). Preliminary results in sentinel lymph node imaging in mice indicate the advantages of multimodal imaging.


Asunto(s)
Óxido Ferrosoférrico/química , Fluoruros/química , Imagen por Resonancia Magnética/métodos , Nanopartículas/química , Imagen Óptica/métodos , Tomografía de Emisión de Positrones/métodos , Itrio/química , Animales , Difosfonatos/química , Difosfonatos/farmacocinética , Óxido Ferrosoférrico/farmacocinética , Fluoruros/farmacocinética , Masculino , Ratones Endogámicos C57BL , Ratones Desnudos , Imagen Multimodal/métodos , Polietilenglicoles/química , Polietilenglicoles/farmacocinética , Tomografía Computarizada de Emisión de Fotón Único/métodos , Itrio/farmacocinética
12.
PLoS One ; 10(11): e0143566, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26599572

RESUMEN

Freshly cut beech deadwood was enriched in the canopy and on the ground in three cultural landscapes in Germany (Swabian Alb, Hainich-Dün, Schorfheide-Chorin) in order to analyse the diversity, distribution and interaction of wood-inhabiting fungi and beetles. After two years of wood decay 83 MOTUs (Molecular Operational Taxonomic Units) from 28 wood samples were identified. Flight Interception Traps (FITs) installed adjacent to the deadwood enrichments captured 29.465 beetles which were sorted to 566 species. Geographical 'region' was the main factor determining both beetle and fungal assemblages. The proportions of species occurring in all regions were low. Statistic models suggest that assemblages of both taxa differed between stratum and management praxis but their strength varied among regions. Fungal assemblages in Hainich-Dün, for which the data was most comprehensive, discriminated unmanaged from extensively managed and age-class forests (even-aged timber management) while canopy communities differed not from those near the ground. In contrast, the beetle assemblages at the same sites showed the opposite pattern. We pursued an approach in the search for fungus-beetle associations by computing cross correlations and visualize significant links in a network graph. These correlations can be used to formulate hypotheses on mutualistic relationships for example in respect to beetles acting as vectors of fungal spores.


Asunto(s)
Biodiversidad , Escarabajos , Hongos , Simbiosis , Madera/microbiología , Madera/parasitología , Animales , Ecosistema , Bosques , Hongos/clasificación , Hongos/genética , Árboles
13.
FEMS Microbiol Ecol ; 91(6)2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25953856

RESUMEN

Decaying wood hosts a large diversity of seldom investigated protists. Environmental sequencing offers novel insights into communities, but has rarely been applied to saproxylic protists. We investigated the diversity of bright-spored wood-inhabiting Myxomycetes by environmental sequencing. Myxomycetes have a complex life cycle culminating in the formation of mainly macroscopic fruiting bodies, highly variable in shape and colour that are often found on decaying logs. Our hypothesis was that diversity of bright-spored Myxomycetes would increase with decay. DNA was extracted from wood chips collected from 17 beech logs of varying decay stages from the Hainich-Dün region in Central Germany. We obtained 260 partial small subunit ribosomal RNA gene sequences of bright-spored Myxomycetes that were assembled into 29 OTUs, of which 65% were less than 98% similar to those in the existing database. The OTU richness revealed by molecular analysis surpassed that of a parallel inventory of fruiting bodies. We tested several environmental variables and identified pH, rather than decay stage, as the main structuring factor of myxomycete distribution.


Asunto(s)
ADN Protozoario/genética , Fagus/parasitología , Mixomicetos/genética , Madera/parasitología , Secuencia de Bases , Biodiversidad , Eucariontes , Alemania , Mixomicetos/clasificación , Mixomicetos/aislamiento & purificación , Análisis de Secuencia de ADN , Madera/química
14.
Microb Ecol ; 69(4): 905-13, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25749938

RESUMEN

Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.


Asunto(s)
Bacterias/genética , Agricultura Forestal/métodos , Bosques , Hongos/genética , Hojas de la Planta/química , Microbiología del Suelo , Bacterias/metabolismo , ADN Intergénico/genética , ADN Intergénico/metabolismo , ADN Espaciador Ribosómico/genética , ADN Espaciador Ribosómico/metabolismo , Hongos/metabolismo , Alemania
15.
PLoS One ; 10(3): e0118967, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25749323

RESUMEN

Due to the high diversity of bacteria in many ecosystems, their slow generation times, specific but mostly unknown nutrient requirements and syntrophic interactions, isolation based approaches in microbial ecology mostly fail to describe microbial community structure. Thus, cultivation independent techniques, which rely on directly extracted nucleic acids from the environment, are a well-used alternative. For example, bacterial automated ribosomal intergenic spacer analysis (B-ARISA) is one of the widely used methods for fingerprinting bacterial communities after PCR-based amplification of selected regions of the operon coding for rRNA genes using community DNA. However, B-ARISA alone does not provide any taxonomic information and the results may be severely biased in relation to the primer set selection. Furthermore, amplified DNA stemming from mitochondrial or chloroplast templates might strongly bias the obtained fingerprints. In this study, we determined the applicability of three different B-ARISA primer sets to the study of bacterial communities. The results from in silico analysis harnessing publicly available sequence databases showed that all three primer sets tested are specific to bacteria but only two primers sets assure high bacterial taxa coverage (1406f/23Sr and ITSF/ITSReub). Considering the study of bacteria in a plant interface, the primer set ITSF/ITSReub was found to amplify (in silico) sequences of some important crop species such as Sorghum bicolor and Zea mays. Bacterial genera and plant species potentially amplified by different primer sets are given. These data were confirmed when DNA extracted from soil and plant samples were analyzed. The presented information could be useful when interpreting existing B-ARISA results and planning B-ARISA experiments, especially when plant DNA can be expected.


Asunto(s)
Bacterias/aislamiento & purificación , Bacterias/clasificación , Bacterias/genética , Biodiversidad , Cartilla de ADN , Genes Bacterianos , Reacción en Cadena de la Polimerasa , ARN Ribosómico/genética , Programas Informáticos , Microbiología del Suelo
16.
Microb Ecol ; 70(2): 390-9, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25687125

RESUMEN

Soil fungi play an essential role in the decomposition of plant-derived organic material entering soils. The quality and quantity of organic compounds vary seasonally as well as with soil depth. To elucidate how these resources affect fungal communities in an arable soil, a field experiment was set up with two plant species, maize and wheat. Resource availability was experimentally manipulated by maize litter input on one half of these maize and wheat plots after harvest in autumn. Fungal biomass was determined by ergosterol quantification, and community structure was investigated by fungal automated ribosomal intergenic spacer analysis (F-ARISA). An annual cycle was assessed across a depth gradient, distinguishing three soil habitats: the plough layer, rooted soil below the plough layer, and deeper root-free soil. Fungal communities appeared highly dynamic and varied according to soil depth and plant resources. In the plough layer, the availability of litter played a dominant role in shaping fungal communities, whereas in the rooted layer below, community structure and biomass mainly differed between plant species. This plant effect was also extended into the root-free soil at a depth of 70 cm. In winter, the availability of litter also affected fungal communities in deeper soil layers, suggesting vertical transport processes under fallow conditions. These distinct resource effects indicate diverse ecological niches along the soil profile, comprising specific fungal metacommunities. The recorded responses to both living plants and litter point to a central role of fungi in connecting primary production and decomposition within the plant-soil system.


Asunto(s)
Hongos/fisiología , Microbiología del Suelo , Biomasa , Ecosistema , Hongos/aislamiento & purificación , Hongos/metabolismo
17.
Sci Rep ; 4: 7014, 2014 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-25388562

RESUMEN

The widespread paradigm in ecology that community structure determines function has recently been challenged by the high complexity of microbial communities. Here, we investigate the patterns of and connections between microbial community structure and microbially-mediated ecological function across different forest management practices and temporal changes in leaf litter across beech forest ecosystems in Central Europe. Our results clearly indicate distinct pattern of microbial community structure in response to forest management and time. However, those patterns were not reflected when potential enzymatic activities of microbes were measured. We postulate that in our forest ecosystems, a disconnect between microbial community structure and function may be present due to differences between the drivers of microbial growth and those of microbial function.


Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas Fúngicas/metabolismo , Hojas de la Planta/química , Microbiología del Suelo , Suelo/química , Fosfatasa Ácida/metabolismo , Biomasa , Celulasas/metabolismo , Celulosa 1,4-beta-Celobiosidasa/metabolismo , Ecosistema , Europa (Continente) , Fagus/fisiología , Agricultura Forestal/métodos , Bosques , Humanos , Consorcios Microbianos/fisiología , Peroxidasas/metabolismo , Estaciones del Año , Árboles/fisiología
18.
PLoS One ; 9(4): e93700, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24699676

RESUMEN

Leaf litter decomposition is the key ecological process that determines the sustainability of managed forest ecosystems, however very few studies hitherto have investigated this process with respect to silvicultural management practices. The aims of the present study were to investigate the effects of forest management practices on leaf litter decomposition rates, nutrient dynamics (C, N, Mg, K, Ca, P) and the activity of ligninolytic enzymes. We approached these questions using a 473 day long litterbag experiment. We found that age-class beech and spruce forests (high forest management intensity) had significantly higher decomposition rates and nutrient release (most nutrients) than unmanaged deciduous forest reserves (P<0.05). The site with near-to-nature forest management (low forest management intensity) exhibited no significant differences in litter decomposition rate, C release, lignin decomposition, and C/N, lignin/N and ligninolytic enzyme patterns compared to the unmanaged deciduous forest reserves, but most nutrient dynamics examined in this study were significantly faster under such near-to-nature forest management practices. Analyzing the activities of ligninolytic enzymes provided evidence that different forest system management practices affect litter decomposition by changing microbial enzyme activities, at least over the investigated time frame of 473 days (laccase, P<0.0001; manganese peroxidase (MnP), P = 0.0260). Our results also indicate that lignin decomposition is the rate limiting step in leaf litter decomposition and that MnP is one of the key oxidative enzymes of litter degradation. We demonstrate here that forest system management practices can significantly affect important ecological processes and services such as decomposition and nutrient cycling.


Asunto(s)
Enzimas/metabolismo , Bosques , Lignina/metabolismo , Hojas de la Planta , Europa (Continente)
19.
PLoS One ; 9(4): e95557, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24763280

RESUMEN

Fungal secretory peroxidases mediate fundamental ecological functions in the conversion and degradation of plant biomass. Many of these enzymes have strong oxidizing activities towards aromatic compounds and are involved in the degradation of plant cell wall (lignin) and humus. They comprise three major groups: class II peroxidases (including lignin peroxidase, manganese peroxidase, versatile peroxidase and generic peroxidase), dye-decolorizing peroxidases, and heme-thiolate peroxidases (e.g. unspecific/aromatic peroxygenase, chloroperoxidase). Here, we have repeatedly observed a widespread expression of all major peroxidase groups in leaf and needle litter across a range of forest ecosystems (e.g. Fagus, Picea, Acer, Quercus, and Populus spp.), which are widespread in Europe and North America. Manganese peroxidases and unspecific peroxygenases were found expressed in all nine investigated forest sites, and dye-decolorizing peroxidases were observed in five of the nine sites, thereby indicating biological significance of these enzymes for fungal physiology and ecosystem processes. Transcripts of selected secretory peroxidase genes were also analyzed in pure cultures of several litter-decomposing species and other fungi. Using this information, we were able to match, in environmental litter samples, two manganese peroxidase sequences to Mycena galopus and Mycena epipterygia and one unspecific peroxygenase transcript to Mycena galopus, suggesting an important role of this litter- and coarse woody debris-dwelling genus in the disintegration and transformation of litter aromatics and organic matter formation.


Asunto(s)
Basidiomycota/enzimología , Proteínas Fúngicas/metabolismo , Peroxidasas/metabolismo , Microbiología del Suelo , Secuencia de Aminoácidos , Bosques , Proteínas Fúngicas/genética , Datos de Secuencia Molecular , Peroxidasas/genética , Filogenia , Análisis de Secuencia de ADN
20.
Biomaterials ; 35(22): 5840-6, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24768194

RESUMEN

Magnetic nanoparticles (NPs) MnFe2O4 and Fe3O4 were stabilised by depositing an Al(OH)3 layer via a hydrolysis process. The particles displayed excellent colloidal stability in water and a high affinity to [(18)F]-fluoride and bisphosphonate groups. A high radiolabeling efficiency, 97% for (18)F-fluoride and 100% for (64)Cu-bisphosphonate conjugate, was achieved by simply incubating NPs with radioactivity solution at room temperature for 5 min. The properties of particles were strongly dependant on the thickness and hardness of the Al(OH)3 layer which could in turn be controlled by the hydrolysis method. The application of these Al(OH)3 coated magnetic NPs in molecular imaging has been further explored. The results demonstrated that these NPs are potential candidates as dual modal probes for MR and PET. In vivo PET imaging showed a slow release of (18)F from NPs, but no sign of efflux of (64)Cu.


Asunto(s)
Hidróxido de Aluminio , Medios de Contraste , Compuestos Férricos , Óxido Ferrosoférrico , Compuestos de Manganeso , Nanopartículas , Hidróxido de Aluminio/química , Animales , Medios de Contraste/química , Femenino , Compuestos Férricos/química , Óxido Ferrosoférrico/química , Radioisótopos de Flúor/química , Imagen por Resonancia Magnética , Compuestos de Manganeso/química , Ratones , Nanopartículas/química , Tomografía de Emisión de Positrones
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