Project description:Freshwater environments such as rivers receive effluent discharges from wastewater treatment plants, representing a potential hotspot for antibiotic resistance genes (ARGs). These effluents also contain low levels of different antimicrobials including biocides and antibiotics such as sulfonamides that can be frequently detected in rivers. The impact of such exposure on ARG prevalence and microbial diversity of riverine environment is unknown, so the aim of this study was to investigate the release of a sub-lethal concentration (<4 g L-1) of the sulfonamide compound sulfamethoxazole (SMX) on the river bacterial microbiome using a microflume system. This system was a semi-natural in-vitro microflume using river water (30 L) and sediment, with circulation to mimic river flow. A combination of ‘omics’ approaches were conducted to study the impact of SMX exposure on the microbiomes within the microflumes. Metaproteomics did not show differences in ARGs expression with SMX exposure in water.
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:Seagrass meadows are highly productive ecosystems that are considered hotspots for carbon sequestration. The decline of seagrass meadows of various species has been documented worldwide, including that of Cymodocea nodosa, a widespread seagrass in the Mediterranean Sea. To assess the influence of seagrass decline on the metabolic profile of sediment microbial communities, metaproteomes from two sites, one without vegetation and one with a declining Cymodocea nodosa meadow, were characterised at monthly intervals from July 2017 to October 2018. The differences in the metabolic profile observed between the vegetated and nonvegetated sediment before the decline were more pronounced in the deeper parts of the sediment and disappeared with the decay of the roots and rhizomes. During the decline, the protein richness and diversity of the metabolic profile of the microbial communities inhabiting the nonvegetated sediment became similar to those observed for the vegetated communities. Temporal shifts in the structure of the metabolic profile were only observed in the nonvegetated sediment and were also more pronounced in the deeper parts of the sediment. The assessment of the dynamics of proteins involved in the degradation of organic matter, such as ABC transporters, fermentation-mediating enzymes, and proteins involved in dissimilatory sulphate reduction, reflected the general dynamics of the metabolic profile. Overall, the metabolic profile of the microbial communities inhabiting the nonvegetated sediment was influenced by the decline of seagrass, with stronger shifts observed in the deeper parts of the sediment.
Project description:Due to difficulties inherent in designating conservation units for effective species management and conservation, the use of multiple complementary sources of information is required to identify and assess the designation of conservation units based on the degree of variation among populations within a species. In this study, we combined estimates of microsatellite and transcriptomic variation to assess the population structure and potential for adaptive variation of threatened Atlantic salmon, Salmo salar, among rivers in the Bay of Fundy. In general, population structure identified by genetic differentiation was consistent with the patterns of variation in gene expression. Both data sets provided clear indication of strong regional differentiation between rivers located within the inner Bay of Fundy relative to rivers located within the outer Bay of Fundy or the Southern Uplands region. There was also support for more refined population structure; there was some differentiation in both microsatellite and gene expression patterns between salmon from rivers in the two regions of the inner Bay of Fundy: Chignecto Bay and Minas Basin. Consistent patterns apparent in the genetic and transcriptomic dataset indicate that Atlantic salmon populations from the inner and outer Bay of Fundy reflect unique genetic lineages, with some evidence of unique genetic legacies between regions of the inner Bay of Fundy, and even between individual rivers within a region. Consistency of the microarray data across two years helps to validate the use of this technique as a useful tool in assessment of variation among wild populations for species conservation.
Project description:Due to difficulties inherent in designating conservation units for effective species management and conservation, the use of multiple complementary sources of information is required to identify and assess the designation of conservation units based on the degree of variation among populations within a species. In this study, we combined estimates of microsatellite and transcriptomic variation to assess the population structure and potential for adaptive variation of threatened Atlantic salmon, Salmo salar, among rivers in the Bay of Fundy. In general, population structure identified by genetic differentiation was consistent with the patterns of variation in gene expression. Both data sets provided clear indication of strong regional differentiation between rivers located within the inner Bay of Fundy relative to rivers located within the outer Bay of Fundy or the Southern Uplands region. There was also support for more refined population structure; there was some differentiation in both microsatellite and gene expression patterns between salmon from rivers in the two regions of the inner Bay of Fundy: Chignecto Bay and Minas Basin. Consistent patterns apparent in the genetic and transcriptomic dataset indicate that Atlantic salmon populations from the inner and outer Bay of Fundy reflect unique genetic lineages, with some evidence of unique genetic legacies between regions of the inner Bay of Fundy, and even between individual rivers within a region. Consistency of the microarray data across two years helps to validate the use of this technique as a useful tool in assessment of variation among wild populations for species conservation.
Project description:Functional redundancy in bacterial communities is expected to allow microbial assemblages to survive perturbation by allowing continuity in function despite compositional changes in communities. Recent evidence suggests, however, that microbial communities change both composition and function as a result of disturbance. We present evidence for a third response: resistance. We examined microbial community response to perturbation caused by nutrient enrichment in salt marsh sediments using deep pyrosequencing of 16S rRNA and functional gene microarrays targeting the nirS gene. Composition of the microbial community, as demonstrated by both genes, was unaffected by significant variations in external nutrient supply, despite demonstrable and diverse nutrient–induced changes in many aspects of marsh ecology. The lack of response to external forcing demonstrates a remarkable uncoupling between microbial composition and ecosystem-level biogeochemical processes and suggests that sediment microbial communities are able to resist some forms of perturbation. nirS gene diversity from two salt marsh experiments, GSM (4 treatments, 8 samples, duplicate arrays, four replicate blocks per array, 8 arrays per slide) and PIE (2 treatments, 16 samples, duplicate arrays four replicate blocks per array, 8 arrays per slide)