Project description:We report the application of transcriptome sequencing technology for high-throughput profiling of Serratia marcescens for producing prodigiosin. By obtaining over 163 million bases of sequence from Serratia marcescens genome DNA, we generated transcriptome -state maps of Serratia marcescens 12h cells, 24h cells, and 36h cells at 30C and 37C,respectively. We explored the mechanism of S. marcescens response temperature regulation at the transcription level through transcriptome sequencing technology. We found that the pig gene cluster at low temperature would favor at the transcriptional level, however, higher temperature resulting in instability and loss of enzyme activity. Numerous amino acid metabolic pathways involved in prodigiosin biosynthesis in S. marcescens responded to temperature changes, and metabolic fluxes were directed towards prodigiosin biosynthesis. At the same time, quorum sensing, two-component regulatory system and sRNA were stimulated by temperature to regulate PG biosynthesis and involve strain virulence and exclusive genes. Moreover, inhibition factors was the one reason for S. marcescens incapable synthesis of prodigiosin at 37C. This study laid a good foundation for understanding the biological functions of prodigiosin, improving the temperature tolerance of industrial strains, and excavating temperature-sensitive regulatory elements.
Project description:In order to identify mRNA and sRNAs associated with the RNA-binding protein Hfq in Serratia marcescens strain Db10, Hfq-bound RNA was immunoprecipitated from a strain encoding an Hfq-3FLAG fusion protein at the normal location and sequenced, in parallel with the wild type strain (no fusion) as negative control. Additionally global transcriptional start site mapping was performed on total RNA, with or without TEX treatment, isolated from wild type Serratia marcescens. The data was used to identify regions of mRNA and sRNAs associated with Hfq in this organism. Associated work in Serratia marcescens Db10, an opportunistic bacterial pathogen, has shown that Hfq is essential for virulence in several models and exerts a wide-ranging impact on the transcriptome and, particularly, genes encoding virulence factors.
Project description:In order to identify changes in the global mRNA transcriptome caused by deletion of the RNA-binding protein Hfq in Serratia marcescens, total mRNA was isolated from wild type Serratia marcescens Db10 and an otherwise isogenic strain carrying an in-frame deletion of the hfq gene (SMDB11_4482) and analysed by RNAseq. Four independent biological replicates were sequenced for each strain using the Illumina HiSeq platform. The data was used to identify the nature and extent of changes in transcript level between the two strains and to inform on the role of Hfq in virulence of Serratia marcescens, an opportunist bacterial pathogen.
Project description:The EepR protein is a two-component response regulator protein in the bacterium Serratia marcescens. Mutation of the eepR gene results in pleiotropic changes including reduced expression of secondary metabolites and proteases.
Project description:The GumB protein is an IgaA-family member that negatively regulates the Rcs stress response system in the bacterium Serratia marcescens. Mutation of the gumB gene results in increased RCs system activity of numerous genes including those involved in flagellar based motility and capsular polysaccharide formation.
Project description:Serratia marcescens (S. marcescens), an opportunistic human pathogen, has been identified as a major cause of nosocomial infection and outbreaks. The purpose of this analysis is to examine the S. marcescens (ATCC 13880) protein profile using a high resolution mass spectrometry (MS). S. marcescens ATCC 13880 strain was grown in Luria-Bertani broth and the protein extracted underwent trypsin digestion followed by simple reverse phase liquid chromatography fractionation. Peptide fractions were then analyzed using Orbitrap Fusion Mass Spectrometry and raw MS data was processed using Proteome Discoverer software. The proteomic study identified 2,541 unique protein groups, corresponding to approximately 54% of the measured protein-coding genes. Bioinformatics analysis of these identified proteins demonstrated their involvement in biological processes such as cell wall organization, caperone-mediated protein folding and ATP binding. To our knowledge, this is the first high-performance S.marcescens proteomics analysis (ATCC 13880). These novel observations provide a key baseline molecular profile of the S. marcescens proteome which will prove to be helpful for the future research in understanding the host-pathogen interactions during infection, elucidating the mechanism of multidrug resistance and for developing novel diagnostic markers or vaccine for the disease.
Project description:The acid tolerance of industrial strains is a significant challenge in the fermentation process. The bacterium Serratia marcescens is part of the Enterobacteriaceae family of eubacteria, which is a potential industrial microorganism. However, the molecular mechanism behind S. marcescens acid resistance is not properly understood. In this study, we screened for novel regulators that respond to acidic conditions by a Tn5G transposon insertion mutagenesis of S. marcescens and found mutations in a gene encoding for the HTH_XRE super-family regulatory protein member, here named xrpA. Using transcriptomics and further experiments, we showed that the xrpA disruption conferred pleiotropic phenotype changes, including highly decreased biomass, altered cell shape, H+-ATPase activity, and deficiency of cell membrane permeability and integrity, compared with those of the parent (JNB5-1) strain at low pH. These data revealed that the molecular mechanism by which xrpA affects acid resistance of S. marcescens is through positive regulation of cell membrane permeability, integrity, and H+-ATPase activity to maintain intracellular homeostasis at low pH. Finally, we constructed an acidic resistant strain JNB5-1/pSX1314 by overexpression of xrpA in S. marcescens and found that its ability to produce prodigiosin by fermentation increased by 21.74% compared with that of parent strain at pH4.0. These results indicated that xrpA regulates tolerance to low pH by transcriptional regulation of acid stress response genes to maintain cell membrane function in S. marcescens.
Project description:Drosophila melanogaster oral infection by the entomopathogen bacteria Serratia marcescens trigger, at the midgut level, a drastic phenotype during the early phase of the exposure. In response to Serratia marcescens virulence factors the enterocytes present a rapid formation of megamitochondria and a subsequent controlled extrusion of the cytoplasm along with damaged organelles, which may constitute a repair mechanism. This results in a thin intestinal epithelium that then recovers its original shape in just a few hours. In order to identify, at the midgut level, the transcriptional modifications induced by Serratia marcescens during this early phase of the infection, we performed a RNAseq transcriptomics analysis of the flies intestine three hours after bacteria ingestion. We found that 144 genes were significantly induced and that 34 genes were repressed at this time point in comparison to the non infected midguts.