Project description:Compare with the gastric cavity without cancerous transformation in atrophic gastritis, analyze the microbiota and metabolomics changes in intestinal type of gastric cancer under the background of atrophic gastritis, and explore the relevant mechanisms.
Project description:Escherichia coli Nissle 1917 (EcN) is a probiotic used for treatment of intestinal disorders. EcN improves gastrointestinal homeostasis and microbiota balance; however little is known about how this probiotic delivers effector molecules to the host. Outer membrane vesicles (OMVs) are constitutively produced by gram-negative bacteria and have a relevant role in bacteria-host interactions. Here we performed proteomic analysis of EcN OMVs. Using 1D SDSD-PAGE and highly sensitive LC-MS/MS analysis we identified 192 EcN vesicular proteins with high confidence in three independent experiments. Of these proteins, 18 were encoded by strain-linked genes and 57 were common to pathogen-derived OMVs. These proteins may contribute to the ability of this probiotic to colonize the human gut as they fulfil functions related to adhesion to host tissues, immune modulation or bacterial survival in host niches. This study describes the first global OMV proteome of a probiotic strain and provides evidence that probiotic-derived OMVs contain proteins that can target these vesicles to the host and mediate their beneficial effects on intestinal function.
Project description:Vibrio species represent one of the most diverse genera of marine bacteria known for their ubiquitous presence in natural aquatic systems. Several members of this genus including Vibrio harveyi are receiving increasing attention lately because they are becoming a source of health problems, especially for some marine organisms widely used in sea food industry. To learn about adaptation changes triggered by V. harveyi during its long-term persistence at elevated temperatures, we studied adaptation of this marine bacterium in sea water microcosms at 30 oC that closely mimicks the upper limits of sea surface temperatures recorded around the globe.
Project description:CdSe nanoparticles (CdSe NPs) are extensively used in the industry of renewable energies and it is regrettably expectedthat these pollutants will sometime soon appear in marine environmentthrough surface runoff, urban effluents and rivers. Bacteria living in estuarine and coastal sediments will be among the first targets of these new pollutants. The pseudomonads are frequently encountered in these ecosystems. They are involved in several biogeochemical cycles and are known for their high resistance to pollutants. Consequently, this study focussing on the effect of CdSe NPs on the marine strain P. fluorescensBA3SM1 is highly relevant for a number of reasons. First, it aims at improving knowledge about the interactions between bacteria and NPs. This is fundamental to use effectively NPs against pathogenic bacteria. Secondly, this study shows that CdSe NPs of 8 nm in diameter cause a decrease in the secretion of siderophorepyoverdine, a secondary metabolite having a key role in microbial ecology and also employed as a virulence factor in human pathogenic strains such as P. aeruginosa. Consequently, this study highlights that CdSe NPs can have an impact on secondary metabolism of bacteria with environmental and medical implications.
Project description:Previous studies have demonstrated that the iron content in marine heterotrophic bacteria is comparatively higher than that of phytoplankton. Therefore, they have been indicated to play a major role in the biogeochemical cycling of iron. In this study, we aimed to investigate the potential of viral lysis as a source of iron for marine heterotrophic bacteria. Viral lysates were derived from the marine heterotrophic bacterium, Vibrio natriegens PWH3a (A.K.A Vibrio alginolyticus). The bioavailability of Fe in the lysates was determined using a model heterotrophic bacterium, namely, Dokdonia sp. strain Dokd-P16, isolated from Fe-limited waters along Line P transect in the Northeastern Pacific Ocean. The bacteria were grown under Fe-deplete or Fe-replete conditions before being exposed to the viral lysate. Differential gene expression following exposure to the viral lysate was analyzed via RNA sequencing to identify differentially expressed genes under iron-replete and iron-deplete conditions. This study would provide novel insights into the role of viral lysis in heterotrophic bacteria in supplying bioavailable iron to other marine microorganisms under iron-limiting and non-limiting conditions. First, the marine heterotrophic bacterium genome, Dokdonia sp. strain Dokd-P16, was sequenced to provide a genomic context for the expression studies. Subsequently, the relative gene expression in Dokdonia sp. strain Dokd-P16 grown under Fe limiting and non-limiting conditions were analyzed. This transcriptomic approach would be utilized to elucidate genes regulated by Fe availability in Dokdonia sp. strain Dokd-P16, which indicate its Fe-related response viral lysate exposure. Taken together, in this study, the transcriptomic responses of Fe-limited and non-limited marine heterotrophic bacteria were analyzed, which provided novel insights into the biological availability of Fe from the viral lysates.