Project description:In this study, microbial communities from triplicate leach-bed anaerobic bioreactors digesting grass were analysed. Each reactor comprised two microbial fractions, one immobilized on grass (biofilm) and the other in a planktonic state present in the leachate. Microbial communities from the two fractions were systematically investigated for community composition and function. This was carried out using DNA, RNA and protein co-extraction. The microbial structure of each fraction was examined using 16S rRNA deep sequencing, while the active members of the consortia were identified using the same approach on cDNA generated from co-extracted RNA samples. Microbial function was investigated using a metaproteomic workflow combining SDS-PAGE and LC-MS/MS analysis.
Project description:Here we report a direct tRNA sequencing protocol and software to simultaneously examine the composition and biological activity of naturally occurring microbial communities. Our analysis of mouse gut microbiome with tRNA-seq and 16S ribosomal RNA gene amplicons revealed comparable microbial community structures, and additional physiological insights into the microbiome through tRNA abundance and modifications.
Project description:The microbial community and enzymes in fermented rice using defined microbial starter, containing Rhizopus oryzae, Saccharomycopsis fibuligera, Saccharomyces cerevisiae and Pediococcus pentosaceus, play an important role in quality of the fermented rice product and its biological activities including melanogenesis inhibitory activity. The microbial metaproteome revealed large-scale proteins expressed by the microbial community to better understand the role of microbiota in the fermented rice.
Project description:Microbial biofilms are omnipresent and implicated in a wide spectrum of areas ranging from bioremediation, food production and biomedical applications. To date little is understood about how biofilm communities develop and function on a molecular level, due to the complexity of these biological systems. Here we ap-ply a meta-proteomics approach to investigate the mechanism driving biofilm formation in a microbial model consortium of four bacterial soil isolates of Steno-trophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paeni-bacillus amylolyticus. The protein abundances between community and the single species biofilms were compared to describe how different metabolic pathways were influenced by inter-species interactions. Our results indicate that community development is dependent on interactions between community members facilitat-ing surface attachment and cross-feeding on specific amino acids. Opposite regu-lation patterns of fermentation and nitrogen pathways in Paenibacillus amylolyticus and Xanthomonas retroflexus may, however, also indicate that competition for lim-ited resources affects community development. Overall our results demonstrate the multitude of pathways characterizing biofilm formation in mixed communities. In order to obtain full taxonomic resolution between closely related species and empower correct protein quantification, we developed a novel pipeline for removing peptide sequences shared between community members from the ref-erence proteomes used for spectral database searches. This pipeline can readily be applied to other microbial communities.
Project description:Known as “The Oriental Botanic Garden” and the natural gene bank of biological species, Shennongjia is one of the most biologically diverse areas in China and a member of UNESCO's World Network of Biosphere Reserves. The macro-organism resources of shennongjia have been deeply explored. However, the microbial community structure was scarcely detected. In this study, we aim to detedect the microbial community along six sites of Shennonajia Mountain and explore the major controlling factor in shaping microbial community with a microarray-based metagenomics tool named GeoChip 4.2.
Project description:Full title: Environmental transcriptome analysis of LfeRT32a in its natural microbial community comparing the biofilm and planktonic modes of life. Extreme acidic environments are characterized among other features by the high metal content and the lack of nutrients (oligotrophy). Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). In the Tinto River (Spain), brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans are abundant. Both microorganisms play a critical role in bioleaching processes for industrial (biominery) and environmental applications (acid mine drainage, bioremediation). The aim of this study was to investigate the physiological differences between the free living (planktonic) and the sessile (biofilm associated) lifestyles of L. ferrooxidans as part of a natural extremely acidophilic community.
Project description:Wastewater treatment plants use a variety of bioreactor types and configurations to remove organic matter and nutrients. Little is known regarding the effects of different configurations and within-plant immigration on microbial community dynamics. Previously, we found that the structure of ammonia-oxidizing bacterial (AOB) communities in a full-scale dispersed growth activated sludge bioreactor correlated strongly with levels of NO2- entering the reactor from an upstream trickling filter (Wells et al 2009). Here, to further examine this puzzling association, we profile within-plant microbial biogeography (spatial variation) and test the hypothesis that substantial microbial immigration occurs along a transect (raw influent, trickling filter biofilm, trickling filter effluent, and activated sludge) at the same full-scale wastewater treatment plant. AOB amoA gene abundance increased >30-fold between influent and trickling filter effluent concomitant with NO2- production, indicating unexpected growth and activity of AOB within the trickling filter. Nitrosomonas europaea was the dominant AOB phylotype in trickling filter biofilm and effluent, while a distinct ‘Nitrosomonas-like’ lineage dominated in activated sludge. Prior time series indicated that this ‘Nitrosomonas-like’ lineage was dominant when NO2- levels in the trickling filter effluent (i.e., activated sludge influent) were low, while N. europaea became dominant in the activated sludge when NO2- levels were high. This is consistent with the hypothesis that NO2- production may co-occur with biofilm sloughing, releasing N. europaea from the trickling filter into the activated sludge bioreactor. Phylogenetic microarray (PhyloChip) analyses revealed significant spatial variation in taxonomic diversity, including a large excess of methanogens in the trickling filter relative to activated sludge and attenuation of Enterobacteriaceae across the transect, and demonstrated transport of a highly diverse microbial community via the trickling filter effluent to the activated sludge bioreactor. Our results provide compelling evidence that substantial immigration between coupled process units occurs and may exert significant influence over microbial community dynamics within staged bioreactors.
Project description:Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here, we operated two laboratory-scale sequence batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal (EBPR). Reactors formed two distinct biofilms, a floccular biofilm, consisting of small, loose, microbial aggregates, and a granular biofilm, forming larger, dense, spherical aggregates. Using metaproteomic methods we investigated the proteomic differences between these two biofilm communities, identifying a total of 2022 unique proteins. Both biofilms contained proteins that were indicative of core EBPR metabolisms and cellular function. To understand the proteomic differences between floccular and granular biofilm communities, we compared protein abundances that were statistically enriched in both biofilm states (alpha level = 0.05). Floccular biofilms were enriched with pathogenic secretion systems suggesting a previously unrecognized, highly competitive, mixed microbial community. Comparatively, granular biofilms revealed a high stress environment with evidence of nutrient starvation, phage predation pressure, extracellular polymeric substance (EPS) synthesis, and increased cell lysis. Granular biofilms enriched outermembrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement core EBPR metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter–enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability.
Project description:Prolific heterotrophic biofilm growth is a common occurrence in airport receiving streams containing deicer and anti-icer runoff. This study investigated relations of heterotrophic biofilm prevalence and community composition to environmental conditions at stream sites upstream and downstream of Milwaukee Mitchell International Airport in Milwaukee, WI, during two deicing seasons (2009–2010 and 2010–2011). Modern genetic tools (such as microarray) have not previously been applied to biofilm communities in this type of setting. We used microarray results to characterize biofilm community composition as well as the response of the biofilm community to environmental factors (i.e., organic content (using chemical oxygen demand concentration) and temperature).