Project description:Sulfate reducing bacteria (SRB), which can produce hydrogen sulfide in sewers, can lead to severe odor problems and asset deterioration due to the sulfide induced concrete corrion. Recently, free nitrou acid (FNA) has been discovered as a promising antimicrobial agent to inhibit SRB activities thereby limiting sulfide production in sewers. However, knowledge of bacteria response dynamics to the increasing levels of FNA is largely unkown.In this study, we detected the whole cell protein production and protein expression dynamics of D. vulgaris by SWATH-MS in the presence of four FNA concentrations (0, 1.0, 4.0 and 8.0 μg N/L) with three treatment time peirods after FNA addition (2, 8 and 12 h). From this a more comprehensive understanding of the FNA effects on D. vulgaris was obtained and the key determinants for withstanding FNA over incubation periods were verified in this sewer corrosion relevant strain.
Project description:Stress response of Methylococcus capsulatus str.Bath toward hydrogen sulfide (H2S) was investigated via physiological study and transcriptomic profiling. M. capsulatus (Bath) can grow and tolerate up to 0.75%vol H2S in headspace. Vast change in pH suggests biological relevant sulfide oxidation. Dozens of H2S-sensitive genes were identified from comparison of cell transcriptome in different H2S concentrations. Mc sulfide quinone reductase (SQR) and persulfide dioxygenase were found to be active during sulfide detoxification. Moreover, xoxF, a novel lanthanide(Ln)-dependent methanol dehydrogenase (MDH) was overexpressed in H2S while mxaF, a calcium-dependent MDH, was down-regulated, and such MDH switch phenomenon is also well known to be induced by addition of lanthanide via an as-yet-unknown mechanism. Activities in quorum sensing and RND efflux pump also suggest their role in sulfide detoxification, and might provide insight on the xoxF/mxaF switch mechanism.
Project description:Interventions: Case series:nill;The control group:nill
Primary outcome(s): Hydrogen sulfide;Pathological diagnosis
Study Design: Case-Control study
Project description:The effect of sulfide stress on Desulfovibrio vulgaris Hildenborough (DvH) gene expression was determined by comparing the gene expression profiles of DvH under conditions in which sulfide was allowed to accumulate (high sulfide, average concentration 10 mM) against DvH cells grown under conditions in which sulfide was removed by continuous gassing (low sulfide, average concentration 1 mM). High sulfide significantly decreased the instantaneous growth rate constant and final cell density of the culture indicating a decreased bioenergetic fitness. Changes in gene expression caused by exposure to high sulfide were determined using full-genome DvH microarrays. The transcription of ribosomal protein-encoding genes was decreased, in agreement with the lower growth rate of DvH under high sulfide conditions. Interestingly, expression of the gene for DsrD, located downstream of the genes for dissimilatory sulfite reductase (DsrAB) was also strongly down-regulated. In contrast, the expression of many genes involved in iron accumulation, stress response and proteolysis, and chemotaxis were increased. This indicates that high sulfide represents a significant stress condition, in which the bioavailability of metals like iron may be lowered and in which proteins (e.g. metalloenzymes) may need to be refolded, or proteolytically degraded. Overall this leads to a reduced growth rate and less efficient biomass production with available resources. For each condition 2 unique biological samples were hybridized to 4 arrays that each contained duplicate spots. Genomic DNA was used as universal reference.
Project description:The effect of sulfide stress on Desulfovibrio vulgaris Hildenborough (DvH) gene expression was determined by comparing the gene expression profiles of DvH under conditions in which sulfide was allowed to accumulate (high sulfide, average concentration 10 mM) against DvH cells grown under conditions in which sulfide was removed by continuous gassing (low sulfide, average concentration 1 mM). High sulfide significantly decreased the instantaneous growth rate constant and final cell density of the culture indicating a decreased bioenergetic fitness. Changes in gene expression caused by exposure to high sulfide were determined using full-genome DvH microarrays. The transcription of ribosomal protein-encoding genes was decreased, in agreement with the lower growth rate of DvH under high sulfide conditions. Interestingly, expression of the gene for DsrD, located downstream of the genes for dissimilatory sulfite reductase (DsrAB) was also strongly down-regulated. In contrast, the expression of many genes involved in iron accumulation, stress response and proteolysis, and chemotaxis were increased. This indicates that high sulfide represents a significant stress condition, in which the bioavailability of metals like iron may be lowered and in which proteins (e.g. metalloenzymes) may need to be refolded, or proteolytically degraded. Overall this leads to a reduced growth rate and less efficient biomass production with available resources.