Project description:We established simple synthetic microbial communities in a microcosm model system to determine the mechanisms that underlay cross-feeding in microbial methane-consuming communities. Co-occurring strains from Lake Washington sediment were used that are involved in methane consumption, a methanotroph and two non-methanotrophic methylotrophs.
Project description:The contamination of marine ecosystems with microplastics, such as the polymer polyethylene, a commonly used component of single-use packaging, is of global concern. Although it has been suggested that biodegradable polymers, such as polylactic acid, may be used to replace some polyethylene packaging, little is known about their effects on marine organisms. Blue mussels, Mytilus edulis, have become a “model organism” for investigating the effects of microplastics in marine ecosystems. We show here that repeated exposure, over a period of 52 days in an outdoor mesocosm setting, of M. edulis to polyethylene microplastics reduced the number of byssal threads produced and the attachment strength (tenacity) by ~50%. Exposure to either type of microplastic altered the haemolymph proteome and, although a conserved response to microplastic exposure was observed, overall polyethylene resulted in more changes to protein abundances than polylactic acid. Many of the proteins affected are involved in vital biological processes, such as immune- and stress- regulation, metabolism and cellular and structural development. Our study highlights the utility of mass spectrometry-based proteomics to assess the health of key marine organisms and identifies the potential mechanisms by which microplastics, both conventional and biodegradable, could affect their ability to form and maintain reefs.
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: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:Plastics are one of the most preoccupying emerging pollutants. Macroplastics released in the environment degrade into microplastics and nanoplastics. Because of their small size, these micro and nano plastic particles can enter the food chain and, in addition to their ecotoxicological effects, contaminate humans with still poorly known biological effects. Plastics being particulate pollutants, they are handled in the human body by scavenger cells such as macrophages, which are important players in the immune system. Because of all the potential problems, it is advocated to replace fossil fuel-based plastics by bio-based and bio-degradable plastics, among which poly-hydroxyalkanoates are the most promising. However, the effects of these on mammalian cells are even less known than those of fossil fuel-based plastics. We therefore designed a study aiming at investigating the effects of polylactic acid (PLA) nanoparticles on macrophages. Indeed, being a plastic, PLA is known to fragment and liberate micro and nanoparticles, exactly as conventional plastics. These particles will be internalized by macrophages and may induce functional consequences on these cells. Proteomics showed important adaptive changes of the proteome in response to exposure to PLA, and several important pathways such as mitochondrion, lysosomes or endoplasmic reticulum were highlighted by the proteomic analysis. However, validation experiments showed that most of these changes were homeostatic and allowed the cells to keep these functions unaltered. When the inflammatory response was examined, no major increase in the secretion of tumor necrosis factor or interleukin 6 was observed. However, the secretion of these cytokines in response to lipopolysaccharide was altered after exposure to PLA. The production of interleukin 6 was decreased, while the production of tumor necrosis factor, showing a complex alteration of cellular responses after exposure to PLA nanoparticles. In conclusion, these results provide a better understanding of the responses of macrophages to exposure to the biodegradable PLA nanoparticles.
Project description:Microplastics represent a growing environmental concern for the oceans due to their potential capability to adsorb different classes of pollutants, thus representing a still unexplored source of exposure for aquatic organisms. In this study polystyrene (PS) microplastics were characterized for their capability to adsorb pyrene (PYR) as model compound for polycyclic aromatic hydrocarbons, and transfer this chemical to filter feeding mussels Mytilus galloprovincialis. Gene expression analyses of Mytilus galloprovincialis exposed to polystyrene (PS) microplastics and to polystyrene contaminated with pyrene (PS-PYR) have been performed trough a DNA microarray platform.