Project description:Marine microbial communities are critical for biogeochemical cycles and the productivity of ocean ecosystems. Primary productivity, at the base of marine food webs, is constrained by nutrient availability in the surface ocean, and nutrient advection from deeper waters can fuel photosynthesis. In this study, we compared the transcriptional responses by surface microbial communities after experimental deep water mixing to the transcriptional patterns of in situ microbial communities collected with high-resolution automated sampling during a bloom in the North Pacific Subtropical Gyre. Transcriptional responses were assayed with the MicroTOOLs (Microbiological Targets for Ocean Observing Laboratories) marine environmental microarray, which targets all three domains of life and viruses. The experiments showed that mixing of deep and surface waters substantially affects the transcription of photosystem and nutrient response genes among photosynthetic taxa within 24 hours, and that there are specific responses associated with the addition of deep water containing particles (organisms and detritus) compared to filtered deep water. In situ gene transcription was most similar to that in surface water experiments with deep water additions, showing that in situ populations were affected by mixing of nutrients at the six sampling sites. Together, these results show the value of targeted metatranscriptomes for assessing the physiological status of complex microbial communities.
Project description:Polylactic acid (PLA) is a promising biodegradable material used in various fields, such as mulching films and disposable packaging materials. Biological approaches for completely degrading biodegradable polymers can provide environmentally friendly solutions. However, to our knowledge, no studies have performed transcriptome profiling to analyze PLA-degrading genes of PLA-degrading bacteria. Therefore, this study reports for the first time an RNA sequence approach for tracing genes involved in PLA biodegradation in the PLA-degrading bacterium Brevibacillus brevis. In the interpretation results of the differentially expressed genes, the hydrolase genes mhqD and nap and the serine protease gene besA were up-regulated by a fold change of 7.97, 4.89, and 4.09, respectively. This result suggests that hydrolases play a key role in PLA biodegradation by B. brevis. In addition, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that genes implicated in biofilm formation were upregulated. The biodegradation of PLA starts with bacteria attaching to the surface of PLA and forming a biofilm. Therefore, it could be confirmed that the above genes were up-regulated for access to PLA and biodegradation. Our results provide transcriptome-based insights into PLA biodegradation, which pitch a better understanding of microbial biodegradation of plastics.
Project description:Environmental influences such as infections and dietary changes strongly affect a host’s microbiota. In the steady state, however, host genetics may influence the microbiota composition, as suggested by the greater similarity between the microbiomes of identical twin pairs compared to non-identical twins. Understanding the role of polymorphic mechanisms in regulating the commensal communities is complicated by the variability of human genomes and microbiomes, and by microbial sensitivity to the environment. Animal studies allow genetic modifications, but are also sensitive to influences known as ‘cage’ or ‘legacy’ effects. Here, we analyzed ex-germ-free mice of various genetic backgrounds, including immunodeficient and Major Histocompatibility Complex (MHC)-congenic strains repopulated with identical input microbiota. We found that the host’s genetic polymorphic mechanisms did indeed affect the gut microbiome and that both innate (e.g. anti-microbial peptides, complement, pentraxins and enzymes affecting microbial survival), as well as adaptive (both MHC-dependent and MHC-independent) pathways influenced the microbiota. These polymorphic mechanisms regulated only a limited number of microbial lineages (independently of their abundance). In addition, our comparative analyses suggested that some microbes might benefit from the specific immune responses that they elicit.
Project description:The diversity and environmental distribution of the nosZ gene, which encodes the enzyme responsible for the consumption of nitrous oxide, was investigated in marine and terrestrial environments using a functional gene microarray. The microbial communities represented by the nosZ gene probes showed strong biogeographical separation, with communities from surface ocean waters and agricultural soils significantly different from each other and from those in oceanic oxygen minimum zones. Atypical nosZ genes, usually associated with incomplete denitrification pathways, were detected in all the environments, including surface ocean waters. The abundance of nosZ genes, as estimated by quantitative PCR, was highest in the agricultural soils and lowest in surface ocean waters.
Project description:In this study we characterize microbial community features on the surface of Indian Ocean. 11 samples were collected from Indian Ocean and subjected for quantitative metaproteomics analysis for taxonomic and functional analysis. Our results suggested that metabolic tuning at metaproteomics levels enabled microbial community to sustain stable when subjected to environmental perturbations in the oligotrophic ocean.
Project description:Vast and diverse microbial communities exist within the ocean, performing a variety of metabolic processes that cumulatively influence global chemical cycles. Despite being globally distributed, microbial populations and ocean biochemistry vary across multiple physical scales, beyond our current ability to fully quantify. To better understand the global influence of marine microbiology, we developed a robot capable of sampling ocean biochemistry across basin-scales while still capturing the fine-scale biogeochemical processes therein.
Project description:Analysis of microbial gene expression in response to physical and chemical gradients forming in the Columbia River, estuary, plume and coastal ocean was done in the context of the environmental data base. Gene expression was analyzed for 2,234 individual genes that were selected from fully sequenced genomes of 246 prokaryotic species (bacteria and archaea) as related to the nitrogen metabolism and carbon fixation. Seasonal molecular portraits of differential gene expression in prokaryotic communities during river-to-ocean transition were created using freshwater baseline samples (268, 270, 347, 002, 006, 207, 212).
Project description:Metaproteomics approach was used to investigate the microbial community and diversity of the infant gut to identify different key proteins with metabolic functional roles in the microbiomes of healthy and atopic dermatitis infants in a Thai population-based birth cohort.