Microbial Ecology最新文献

Growing evidence suggests that the gut microbiota is closely intertwined with life-history evolution in a wide range of species, including well-studied model organisms like Drosophila melanogaster. Although recent studies have explored the relationship between gut microbiota and female life-history, the link between gut microbiota and male life-history remains relatively unexplored. In this study, we investigated how gut microbiota changes with male age as well as the associations between gut microbiota composition and male life-history traits in D. melanogaster. Using 22 isolines from the Drosophila melanogaster Genetic Reference Panel (DGRP), we measured lifespan, early/late-life reproduction, and early/late-life physiological performance. We characterized the gut microbiota composition in young (5 days old) and old (26 days old) flies using 16S rDNA sequencing. We observed substantial variation in both male life-history traits and gut microbiota composition across isolines and age groups. Using machine learning, we show that gut microbiota composition could predict the chronological age of the organisms with high accuracy. The most important species contributing to machine learning prediction belonged to the Acetobacter and Ralstonia genera. Associations between gut microbiota and life-history traits were also notable, particularly involving different species from the Acetobacter genus. Our findings suggest that taxa such as Acetobacter may be relevant to the evolutionary ecology of host-microbe interactions in male fruit flies.

Non-Dikarya fungi remain poorly characterized due to their cryptic morphology, cultivation difficulties, and limited representation in reference databases. To investigate their diversity and environmental distribution at a global scale, we reanalyzed over 6000 environmental samples using metabarcoding targeting the V4 region of the 18S rRNA gene, encompassing marine, freshwater, soil, hypersaline, polar, and other habitats. We constructed reference phylogenetic trees based on near full-length 18S rRNA gene sequences to enable accurate placement of short-read amplicon sequence variants (ASVs). This approach yielded robust classification at the phylum level and provided finer-scale clade resolution within major non-Dikarya groups. We delineated precise clades within Chytridiomycota, Microsporidia, Rozellida, and Aphelidea, and unveiled several novel ones. Our results show strong ecological structuring of fungal communities across habitats, with inland systems harboring greater fungal abundance and broader phylogenetic diversity than marine systems. Non-Dikarya fungi were consistently detected across diverse environments, including extreme habitats such as hypersaline lakes, deep sediments, and polar regions, where they were often the dominant fungal taxa. Although most ASVs tended to occur in a limited number of ecologically related habitats, phylogenetically related ASVs within the same clade were often adapted to different environments, indicating ecological diversity within clades. Our findings underscore both the ecological relevance and the cryptic diversity of non-Dikarya fungi in globally distributed environments, including extreme ones. Improved taxonomic resolution and broader reference dataset coverage are required to fully integrate these newly characterized lineages into fungal systematics and environmental surveys.

Hospitals are particularly sensitive environments where immunosuppressed patients might acquire invasive fungal infections. Therefore, it is necessary to carry out periodical environmental microbiological assessments that evaluate the fungal bioburden in air and surfaces from different hospital zones. Current microbiological monitoring protocols at healthcare settings are mostly based on cultivation, while environmental DNA (eDNA) assessments are still scarce and should be further evaluated. To fill this gap, this study combines a large sampling scheme, comprising > 200 samples (air, surface, dust and soil) collected from four zones at three Spanish hospitals in two campaigns (winter and autumn), with two eDNA approaches (DNA metabarcoding and quantitative PCR) to characterize the hospital mycobiomes (diversity, community composition and airborne load), compared to a parallel culture-dependent study. DNA metabarcoding revealed a much more comprehensive inventory of hospital fungi compared to culturing; however, both approaches found similar dominant taxa including a variety of potentially opportunistic human pathogens. Hospital mycobiomes were affiliated to 4 phyla (mostly Ascomycota and Basidiomycota), 35 classes, 114 orders, 305 families, 643 genera and 535 species. The dominant genera, in both air and surfaces from the three hospitals, were Cladosporium, Alternaria, Aureobasidium, Penicillium, Neodidymelliopsis, Aspergillus, Pseudopithomyces and Stemphylium. The yeasts Candida and Clavispora were particularly abundant on high-touch surfaces indoors. The most important explanatory factors for the variance in community composition were the hospital and zone where samples were collected, the type of sample and the sampling campaign. DNA metabarcoding can assist hospital managers by providing an in-depth characterization of the baseline hospital mycobiome during normal operating conditions, as well as identifying and controlling community imbalances and associated health risks under demanding situations such as construction works or reported clinical outbreaks.

Members of the phylum Verrucomicrobiota are abundant yet relatively understudied soil bacteria that play key roles in biogeochemical cycling and plant-microbe interactions. They participate in the carbon (C) and nitrogen (N) cycles through the degradation of complex organic polymers such as cellulose, pectin, and starch - via the production of hydrolytic enzymes (e.g., cellulases, xylanases, chitinases), and through nitrogen transformations including denitrification, ammonification, and nitrogen fixation. Methanotrophic representatives (Methylacidiphilum, Methylacidimicrobium) oxidise methane under acidic or thermophilic conditions, thereby contributing to greenhouse gas mitigation. The ecological distribution and activity of Verrucomicrobiota are strongly influenced by nutrient availability, particularly of C, N, phosphorus (P), and potassium (K). Their variable responses to these elements reflect diverse life-history strategies, encompassing both copiotrophic (r-strategist) and oligotrophic (K-strategist) taxa. While Spartobacteria (e.g., Ca. Udaeobacter) are typically oligotrophic, classes such as Opitutia and Verrucomicrobiae exhibit mixed strategies. Beyond nutrient cycling, several members of the phylum function as plant growth-promoting and stress mitigating bacteria. They produce phytohormones (e.g., indole-3-acetic acid) and siderophores, increase the availability of nitrogen and solubilise phosphate. Some taxa exhibit antioxidant activity and can suppress phytopathogens such as Fusarium oxysporum through secondary metabolite production. These traits suggest a significant potential in soil health improvement. Overall, Verrucomicrobiota represent a functionally diverse and ecologically significant bacterial phylum whose metabolic versatility, adaptive life strategies, and plant-associated traits underscore their central role in sustainable agricultural ecosystems.

The ecological mechanisms governing gut microbial community stability during Alzheimer's disease (AD) progression remain poorly understood. This study employed an ecological network to investigate microbial interactions and stability across cognitively normal controls (CK), individuals with mild cognitive impairment (MCI), and AD patients. We observed a stepwise decline in network complexity across groups, characterized by reduced clustering coefficients and average degree, from CK to AD. While the MCI group exhibited intermediate structural complexity, it displayed the highest vulnerability and lowest robustness, indicating a critical transitional state. Keystone taxa analysis revealed a significant shift in microbial community, with the CK network was enriched with diverse, potentially beneficial keystone taxa, whereas the AD network retained only connector species, and the MCI network showed a complete absence of keystone taxa. Cohesion analysis revealed a non-linear trajectory of microbial interactions, with negative cohesion peaking in MCI. Our findings demonstrate that cognitive decline is associated with a fundamental reorganization of the gut microbial ecosystem. This reorganization pattern reveals a resilient state in health, a vulnerable phase in MCI, and a stable yet dysbiotic configuration in AD, with keystone taxa serving as pivotal regulators of community stability. Community assembly analysis showed a shift from deterministic to stochastic processes during cognitive decline, with weakened host regulatory mechanisms. These findings advance our understanding of the gut microbial ecology in neurodegenerative disease and reveal the mechanism by which microbial communities reorganize network to maintain stability in different cognitive states.

Microbial community dynamics in relation to mesoscale hydrographical features are almost unknown particularly in the pelagic Central-Southern Tyrrhenian Sea. To get a more comprehensive view of phytoplankton community structure and microbial community functioning, datasets of phytoplankton abundance, composition and some microbial enzyme activities (leucine aminopeptidase, LAP, beta-glucosidase, GLU and alkaline phosphatase, AP) from six cruises carried out twenty years ago were analyzed. Hydrographic characteristics identified the presence of both Atlantic Waters (AW) and Tyrrhenian Intermediate Waters (TIW). Size structure of phytoplankton biomass showed an unexpected high contribution of the pico-phytoplankton to the total primary production (> 60%) determining a predominant microbial food web. Phytoplankton distribution patterns varied more significantly on a seasonal rather than spatial scale. Autumn assemblages were characterized by the highest abundance and carbon content, with species mainly belonging to dinoflagellates whose growth was supported by intense microbial activities. In contrast, in the summer diatoms developed in unstable TIW where microbial activity was declining. Enzymatic activities varied in the different water masses and seasons, with high LAP activity in summer AW (s-AW) as well as in deep TIW (d-TIW), while AP and GLU reached their maximum in autumn AW (a-AW), suggesting quick organic matter recycling. Coupled primary production and hydrolysis in mixed AW (m-AW) and in a-AW indicated synchronized autotrophic and heterotrophic processes, while in TIW organic matter was only partially recycled. Overall, microbial metabolism was closely shaped by hydrographic and seasonal dynamics, confirming its key role in biogeochemical cycles. Our data could provide a baseline study for future research dealing with the microbial functioning in this Mediterranean region.

The formation of biofilms in industrial environments poses a significant challenge because of their ability to degrade materials, contaminate products, and harbour pathogenic microorganisms. In the automotive industry, surface treatment systems (STS) used to prepare car bodies can provide a favourable environment for microbial development, driven by the presence of water, organic matter, and variable physicochemical conditions. In this context, the microbial diversity present in the different STS baths of an automotive plant, as well as in the process water, was analysed. Through culture-based methods and molecular analysis, 33 bacterial and 6 yeast species were identified. The results revealed a constant presence of bacteria at all sampling points, whereas yeasts were detected less frequently and in more localized areas (Industrial and Dechromatized Water, E2, Conversion stage, E4 and Passivation stage). This study underscores the importance to enhance cleaning and disinfection protocols in STS, as high bacterial counts persisted even after rinsing stages, in order to prevent economic losses, product degradation and health risks. Furthermore, it highlights the potential use of certain microorganisms in biotechnology and bioremediation applications.

The red swamp crayfish (Procambarus clarkii) is one of the important freshwater aquaculture species in China, but its growth and development are greatly affected by temperature, which makes it difficult to expand its aquaculture range to the northern regions of China. The composition of gut microbes plays a vital role in resisting environmental pressure, and is also an important driving factor for amino acid metabolism in the body. However, little is known about the relationship between microorganisms, metabolism, and cold-resistance ability of P. clarkii. In this study, we performed the cold-resistance and antioxidant ability test, gut microbiota diversity analysis, quantitative analysis of histamine, and bioinformatics analysis of histamine receptor (HR) family on P. clarkii. The results showed that the cold-resistance crayfish exhibited high antioxidant ability and low gut microbiota diversity after acute cold stress. Next, we also found that there was significant correlation between the Lactobacilli genus and histamine abundance, indicating that the excellent cold tolerance ability of crayfish may stem from the degradation of histamine by Lactobacilli. Finally, it was revealed that HR genes had considerable quantity of gene copies, conservative evolution in crustacean lineages and expression differences in low-temperature tolerant populations. These results suggested that the diversity of Lactobacillus mediated changes in histamine metabolism affect antioxidant capacity, which is one of the reasons why P. clarkii exhibits cold resistance ability. This finding provided a theoretical basis for understanding the microorganism-histamine regulation mechanism of red swamp crayfish under cold stress, promoting the breeding and healthy culture of cold-resistance strain.

Drought stress markedly reduces rice yield, with notable genotypic variation in drought tolerance. While the rhizosphere microbiome is regarded as the second genome of plants, how the indica and japonica rice rhizosphere microbial communities respond to deficit irrigation and their relationship with yield remain to be elucidated. Here, we conducted field experiments using 12 indica and 12 japonica rice varieties under full and deficit irrigation regimes. Yield-related traits, including filled grain number, seed setting rate, two-plant yield, and thousand grain weight, were measured, and the rhizosphere microbial communities were characterized by 16S rRNA gene sequencing. In line with previous studies, japonica varieties showed superior drought resistance in terms of yield performance. Both rice genotype and irrigation regime significantly influenced the composition and functional potential of the rhizosphere microbiome. Compared to indica rice, the japonica rice rhizosphere was enriched with more beneficial microorganisms. Enrichment of nitrogen‑metabolism‑related groups, such as Microvirga and Nitrososphaeraceae, may contribute to rhizosphere nitrogen cycling and support nitrogen availability for the rice. Similarly, higher abundance of Streptomyces in japonica varieties under drought conditions may be associated with improved drought tolerance. These microbial genera were closely associated with rice yield. Moreover, the japonica rhizosphere microbiome was less disturbed by water limitation, showing higher stability. Overall, the rhizosphere microbiome of japonica rice exhibited functional optimization under drought stress by promoting the enrichment of beneficial and nitrogen-cycling microbes, thereby enhancing drought resistance and yield stability. This study demonstrated a significant correlation between rhizosphere microbial communities and rice yield, providing fundamental insights that may contribute to future strategies for optimizing crop productivity through microbiome management in sustainable agriculture.

Cultivation of the tropical Blacklip Rock Oyster (BRO) (Saccostrea spathulata) is an emerging Indigenous-led aquaculture industry in the seasonal tropics of northern Australia. However, little is currently known about the potential for pathogen outbreaks in this species. We conducted a year-long study to establish a microbial baseline to identify potential oyster and human health risks to inform future food safety decision making in this nascent industry. In healthy oysters, we identified both the core microbiome of this oyster species and the presence of potential oyster and human pathogens. The core bacteriome comprised nine bacterial families, while the core vibriome comprised the animal pathogens Vibrio harveyi and V. owensii. The potential human pathogen V. parahaemolyticus was detected in some oysters during the wet season, during periods of increased rainfall, turbidity and total nitrogen. The bacteriome and vibriome of oysters were significantly different to the adjacent seawater and therefore we concluded that seawater is not an appropriate surrogate for pathogen risk surveillance in this developing industry. These results provide new knowledge on the microbiology of a previously understudied oyster species and will inform monitoring methods, harvesting and shellfish quality compliance in this emerging Indigenous-led industry.