Project description:Samples collect to investigate the gene activity from microbial populations in marine steel corrosion, and to compare with gene activity in water and bed sediment samples from the surrounding area. The study was undertaken to (1) investigate mechanisms of microbially influenced corrosion (MIC) of marine steel, and (2) compare microbial population gene activity between corrosion and the surrounding environment. Purified DNA (1µg) was labelled with Cy3, purified and hybridised at 42°C for 16h with the GeoChipTM 5.0 on a MAUI hybridisation station (BioMicro, USA).
Project description:Microbiologically influenced corrosion (MIC) is recognized as a considerable threat to carbon steel asset integrity in the oil and gas industry. There is an immediate need for reliable and broadly applicable methods for detection and monitoring of MIC. Proteins associated with microbial metabolisms involved in MIC could serve as useful biomarkers for MIC diagnosis and monitoring. A proteomic study was conducted using a lithotrophically-grown bacteria Desulfovibrio ferrophilus strain IS5, which is known to cause severe electric MIC in seawater environments. Unique proteins, which are differentially and uniquely expressed during severe microbial corrosion by strain IS5, were identified. This includes the detection of a multi-heme cytochrome protein predicted to be involved in extracellular electron transfer in the presence of the carbon steel. Thus, we conclude that newly identified protein biomarker for MIC could be used to generate easy-to-implement immunoassays for reliable detection of microbiological corrosion in the field.
Project description:Increasing atmospheric CO2 concentrations are causing decreased pH over vast expanses of the ocean. This decreasing pH may alter biogeochemical cycling of carbon and nitrogen via the microbial process of nitrification, a key process that couples these cycles in the ocean, but which is often sensitive to acidic conditions. Recent reports indicate a decrease in oceanic nitrification rates under experimentally lowered pH. How composition and abundance of ammonia oxidizing bacteria (AOB) and archaea (AOA) assemblages respond to decreasing oceanic pH, however, is unknown. We sampled microbes from two different acidification experiments and used a combination of qPCR and functional gene microarrays for the ammonia monooxygenase gene (amoA) to assess how acidification alters the structure of ammonia oxidizer assemblages. We show that despite widely different experimental conditions, acidification consistently altered the community composition of AOB by increasing the relative abundance of taxa related to the Nitrosomonas ureae clade. In one experiment this increase was sufficient to cause an increase in the overall abundance of AOB. There were no systematic shifts in the community structure or abundance of AOA in either experiment. These different responses to acidification underscore the important role of microbial community structure in the resiliency of marine ecosystems. SUBMITTER_CITATION: Title: Acidification alters the composition of ammonia oxidizing microbial assemblages in marine mesocosms Journal: Marine Ecology Progress Series Issue: 492 Pages: 1-8 DOI: 10.3354/meps 10526 Authors: Jennifer L Bowen Patrick J Kearns Michael Holcomb Bess B Ward
Project description:16s RNA gene sequencing data from seawater, bed sediment and steel corrosion samples from Shoreham Harbour, UK, collected to allow bacterial species comparisons between microbially influenced corrosion, the surrounding seawater, and the sea bed sediment at the seafloor and 50cm depth below seafloor.
Project description:The secretion of metabolites by plant roots is a key determinant of microbial growth and colonisation. We have used Pisum sativum and its natural symbiont Rhizobium leguminosarum (it can form N2 fixing nodules on pea roots) to study the natural metabolites secreted by roots. To do this root secretion was harvested from pea plants grown under sterile conditions. This root exudate was then concentrated and used as a sole carbon and nitrogen source for growth of the bacteria in the laboratory. These bacteria were harvested in mid-exponential growth and RNA extracted for microarray analysis. As control cultures the bacteria were grown on 30 mM pyruvate as a carbon source and 10 mM ammonium chloride as a nitrogen source and RNA extracted. Two colour microarrays were performed using root exudate cultures versus pyruvate ammonia grown cultures. This was done in biological triplicate.
Project description:About one half of the global, biogenic carbon dioxide fixation into organic matter is driven by microscopic algae in the surface oceans. These microalgal activities generate, among other molecules, polysaccharides that are food for and recycled by bacteria with polysaccharide utilization loci (PULs). These genetic clusters of co-evolved genes, which work together in recognition, depolymerizing and uptake of one type of polysaccharide. However, we rarely know the substrates of PULs present in marine bacteria. Here we investigated the proteomic and physiological response of mannan PULs from marine Flavobacteriia isolated in the North Sea. The genomic clusters of these marine Bacteroidetes are related to PULs of human gut Bacteroides strains, which are known to digest α- and β-mannans from yeasts and plants respectively. Proteomics and defined growth experiments with these types of mannans as sole carbon source confirmed the functional prediction. Our data suggest that biochemical principles established for gut or terrestrial microbes apply to marine bacteria even though the PULs are evolutionary distant. Moreover, our data support discoveries from the 60th reporting mannans in microalgae suggesting that these polysaccharides play an important role in the marine carbon cycle.
Project description:About one half of the global, biogenic carbon dioxide fixation into organic matter is driven by microscopic algae in the surface oceans. These microalgal activities generate, among other molecules, polysaccharides that are food for and recycled by bacteria with polysaccharide utilization loci (PULs). These genetic clusters of co-evolved genes, which work together in recognition, depolymerizing and uptake of one type of polysaccharide. However, we rarely know the substrates of PULs present in marine bacteria. Here we investigated the proteomic and physiological response of mannan PULs from marine Flavobacteriia isolated in the North Sea. The genomic clusters of these marine Bacteroidetes are related to PULs of human gut Bacteroides strains, which are known to digest α- and β-mannans from yeasts and plants respectively. Proteomics and defined growth experiments with these types of mannans as sole carbon source confirmed the functional prediction. Our data suggest that biochemical principles established for gut or terrestrial microbes apply to marine bacteria even though the PULs are evolutionary distant. Moreover, our data support discoveries from the 60th reporting mannans in microalgae suggesting that these polysaccharides play an important role in the marine carbon cycle.
Project description:Influence of the constant full-spectrum light and short-to-long wavelengths of the visible spectrum (red, green and blue lights) and the significance of 12 h photoperiod was tested on heterotrophic marine flavobacteria Siansivirga zeaxanthinifaciens CC-SAMT-1T. RNA-seq analysis revealed remarkable qualitative and quantitative variations in terms of gene expression in CC-SAMT-1T with respect to incident lights. While blue light illumination stimulated expression of genes involved in inorganic carbon metabolism, green˗red lights largely upregulated the genes participating in high-molecular-weight (HMW) organic carbon metabolism. Constant full-spectrum light also displayed the upregulation of genes involved in the metabolism of HMW organic carbon. Thus, the short-to-long wavelengths of visible light and the 12 h photoperiod most likely to play a key role in the marine carbon cycle by tuning heterotrophic bacterial metabolism.