Project description:Anthropogenic perturbations to the nitrogen cycle, primarily through use of synthetic fertilizers, is driving an unprecedented increase in the emission of nitrous oxide (N2O), a potent greenhouse gas, and an ozone depleting substance, causing urgency in identifying the sources and sinks of N2O. Microbial denitrification is a primary contributor to the biotic production of N2O in anoxic regions of soil, marine systems, and wastewater treatment facilities. Here, through comprehensive genome analysis, we show that pathway partitioning is a ubiquitous mechanism of complete denitrification by microbial communities. We have further investigated the mechanisms and consequences of process partitioning through detailed physiological characterization and kinetic modeling of a synthetic community of Rhodanobacter R12 and Acidovorax 3H11. We have discovered that these two bacterial isolates from a heavily NO3- contaminated superfund site complete denitrification through the exchange of nitrite (NO2-) and nitric oxide (NO). Our findings further demonstrate that cooperativity within this denitrifying community emerges through process partitioning of denitrification and other processes, including amino acid metabolism. We demonstrate that certain contexts, such as high NO3-, cause unbalanced growth of community members, due to differences in their substrate utilization kinetics and inter-enzyme competition. The altered growth characteristics of community members drives accumulation of toxic NO2- , which disrupts denitrification causing N2O off gassing.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3) Water and sediment samples were collected after a rain event from Sungei Ulu Pandan watershed of >25km2, which has two major land use types: Residential and industrial. Samples were analyzed for physicochemical variables and microbial community structure and composition. Microbial community structure was determined using PhyoChio (G3)
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3)
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Water and sediment samples were collected after a rain event from Sungei Ulu Pandan watershed of >25km2, which has two major land use types: Residential and industrial. Samples were analyzed for physicochemical variables and microbial community structure and composition. Functional gene abundance was determined using GeoChip.
Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River. Three groups of samples, A, B and C. Every group has 3 replicates.
Project description:Xiangjiang River (Hunan, China) has been contaminated with heavy metal for several decades by surrounding factories. However, little is known about the influence of a gradient of heavy metal contamination on the diversity, structure of microbial functional gene in sediment. To deeply understand the impact of heavy metal contamination on microbial community, a comprehensive functional gene array (GeoChip 5.0) has been used to study the functional genes structure, composition, diversity and metabolic potential of microbial community from three heavy metal polluted sites of Xiangjiang River.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals.
Project description:Anthropogenic perturbations to the nitrogen cycle, primarily through use of synthetic fertilizers, have caused unprecedented increases in the emission of nitrous oxide (N2O) in recent decades. As a potent greenhouse gas, and an ozone depleting substance, understanding the sources and sinks of N2O is of vital importance. Nitrate (NO3-) reducing microbes are a primary contributor to the biotic production of N2O in anoxic regions of soil, marine systems, and wastewater treatment facilities through the process of denitrification. Thus, developing a better understanding of denitrifying microbial communities, and the environmental factors that influence N2O emissions may provide strategies to mitigate emissions in agriculture and wastewater treatment. Here, through comprehensive genome analysis, we show that pathway partitioning is a common strategy utilized by microbial communities to perform complete denitrification. Through detailed physiological characterization and kinetic modeling of a cooperative synthetic community (SynCom) assembled by pairing bacterial isolates from a field site heavily contaminated with NO3-, we also provide insight into the controls of N2O emissions. We demonstrate that members of this SynCom cooperate to perform complete denitrification through exchange of nitrite (NO2-) and nitric oxide (NO), and that community context drives global physiological changes in each member. We identify links between amino acid metabolism and denitrification activity as well as indicators of competition and amino acid exchange. We also show that NO2- toxicity with unbalanced growth of community members drives N2O production, suggesting that this SynCom provides a simplified, environmentally relevant, model of pathway partitioning in denitrifying communities. This SynCom should provide a framework with which to further explore how environmental context can impact cooperation and lead to the production of N2O
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.