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: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:The bacterium Serratia marcescens is a common contaminant of contact lens cases and lenses. Serratamolide is one of the secreted hemolytic/cytotoxic factors which contribute to the virulence of this opportunistic pathogen (PMID 22615766). A newly identified transcription factor (eepR) is essential for serratamolide production (PMID 25897029). In the present study, we used immortalized human corneal-limbal epithelial (HCLE) cells (PMID 12766048) as targets for the secreted products of either wild-type (WT) S. marcescens or an isogenic eepR mutant. Microarray data showed that at sub - cytotoxic levels, the secretome of WT bacteria stimulated a > 2-fold response in 712 unique characterized genes. Analysis showed that immune/inflammatory response pathways are significantly enriched in these genes. The scaled response of eepR, ((eepR - control)/(WT â?? control)), was < 0.5 for 418 of these 712 genes (59%). Pathway analysis of these 2-fold attenuated genes confirmed that they too represented immune/inflammatory responses. These data demonstrate that the serratamolide-deficient eepR mutant evokes a much weaker immune/inflammatory response from a clinically relevant cellular target than does the wild-type bacterium. A common batch of HCLE cells was used. Independent preparations of Serratia marcescens secretomes were made for each experiment.
Project description:The bacterium Serratia marcescens is a common contaminant of contact lens cases and lenses. Serratamolide is one of the secreted hemolytic/cytotoxic factors which contribute to the virulence of this opportunistic pathogen (PMID 22615766). A newly identified transcription factor (eepR) is essential for serratamolide production (PMID 25897029). In the present study, we used immortalized human corneal-limbal epithelial (HCLE) cells (PMID 12766048) as targets for the secreted products of either wild-type (WT) S. marcescens or an isogenic eepR mutant. Microarray data showed that at sub - cytotoxic levels, the secretome of WT bacteria stimulated a > 2-fold response in 712 unique characterized genes. Analysis showed that immune/inflammatory response pathways are significantly enriched in these genes. The scaled response of eepR, ((eepR - control)/(WT – control)), was < 0.5 for 418 of these 712 genes (59%). Pathway analysis of these 2-fold attenuated genes confirmed that they too represented immune/inflammatory responses. These data demonstrate that the serratamolide-deficient eepR mutant evokes a much weaker immune/inflammatory response from a clinically relevant cellular target than does the wild-type bacterium.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Serratia marcescens for 4 hours versus age-matched worms exposed to control lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Bacillus thuringiensis, Staphylococcus aureus, and Xenorhabdus nematophila.
Project description:Transcriptional profiling of P. pacificus young adult worms exposed to pathogen Serratia marcescens for 4 hours versus age-matched worms exposed to control lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode C. elegans to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including , Bacillus thuringiensis DB27, Serratia marcescens and Xenorhabdus nematophila.
Project description:Global amphibian declines and extinction events are currently occurring at an unprecedented rate. While various factors are influencing these declines, one factor that is readily identifiable is disease. Specifically, the fungal pathogen Batrachochytrium dendrobatidis is thought to play a major role in amphibian declines in tropical and neotropical regions of the globe. While the effects of this chytrid fungus have been shown to be devastating, certain individuals and relict populations have shown resistance. This resistance has been attributed in part to the cutaneous microbiome. Many identified bacterial species that make up the microbiome have shown anti-B. dendrobatidis activity in vitro. One bacteria that is commonly associated as being a member of the amphibian microbiome across amphibian species and shows such anti-B. dendrobatidis activity is Serratia marcescens. Here, we look at transcriptomic shifts in gene expression of S. marcescens (high homology to strain WW4) in response to both live and heat-killed B. dendrobatidis.