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Expression data of enterotoxigenic (ETEC) isolate E24377A

ABSTRACT: ETEC is an important human pathogen. Although the mechanism of diarrhea is known in ETEC, the regulatory networks are less understood. This study was conducted to understand the global expression of ETEC isolate E24377A under different growth and environemental conditions. ETEC isolate E24377A was grown in the presence of several chemical signals, including bile salts, glucose, and pre-conditioned media (PCM) from other enteric pathogens. E24377A was also grown to different densities, to see if a quorum sensing mechanism was in place

ORGANISM(S): Shigella Escherichia coli O139:H28 str. E24377A Escherichia coli

PROVIDER: GSE31804 | GEO | 2012/03/01

SECONDARY ACCESSION(S): PRJNA155049

REPOSITORIES: GEO

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Project description:PFGRC has developed a cost effective alternative to complete genome sequencing in order to study the genetic differences between closely related species and/or strains. The comparative genomics approach combines Gene Discovery (GD) and Comparative Genomic Hybridization (CGH) techniques, resulting in the design and production of species microarrays that represent the diversity of a species beyond just the sequenced reference strain(s) used in the initial microarray design. These species arrays may then be used to interrogate hundreds of closely related strains in order to further unravel their evolutionary relationships. Infectious diarrhea is a leading worldwide cause of infant mortality and secondary malnutrition. Enterotoxigenic E. coli (ETEC) is a principal etiology of travelers?diarrhea and a major endemic health threat, especially among children in developing nations where it is estimated to cause hundreds of thousands of deaths each year. Vaccine development for ETEC has been significantly hampered by the remarkable genetic plasticity of E. coli, a comparatively modest understanding of the basic pathogenesis of these organisms, and an uncertainty regarding the degree to which any given antigenic target might be conserved. While experimental and epidemiologic data suggest that a broadly protective vaccine can be achieved, this will most effectively be accomplished in a research environment that fosters sharing of vital resources and open, collaborative interactions among multiple investigators. The proposed project is aimed at providing critical leverage to ongoing international investigative efforts pertaining to ETEC pathogenesis and vaccinology. The flow of genetic information within this group motivated us to identify novel genes for the purpose of creating a species DNA microarray to better understand the ancestral relationships among its members. Based on preliminary MLST genotyping, 11 diverse ETEC strains were selected for sequencing. Sequence information obtained from this project, and from other publicly available sources, led to the development of a comprehensive species microarray for ETEC group members. The availability of the ETEC species DNA microarray has allowed us to carry out a collaborative CGH genotyping project to validate this microarray as well as understand the phylogenomic relationships among members of ETEC group.

Project description:Enterotoxigenic Escherichia coli (ETEC) strains that produce both heat-stable (ST) and heat-labile (LT) enterotoxins cause severe post-weaning diarrhea in piglets. However, the relative importance of the individual enterotoxins to the pathogenesis of ETEC infection is poorly understood. In this study, we investigated the effect on virulence of an F4+ ETEC strain when removing some or all of its enterotoxins. Several isogenic mutant strains were constructed that lack the expression of LT in combination with one or both types of ST enterotoxins (STa and/or STb). Host early immune responses induced by these mutant strains 4h after infection were compared to the wild type strain GIS26 Â (O149:F4ac+, Â LT+ Â STa+ Â STb+). At the same time, the immune response of this wild type ETEC strain was compared to the mock-infected control, demonstrating the expression of porcine inflammatory response genes. For these purposes, the small intestinal segment perfusion (SISP) technique and microarray analysis were used and results were validated by qRT-PCR. We also measured net fluid absorption of pig small intestinal mucosa 4h after infection with wild type ETEC, the mutant strains and PBS (mock-infected). These data indicate an important role for STb in inducing small intestinal secretion early after infection. The microarray analysis of the different mutant strains also revealed an important role for STb in ETEC-induced immune response by the significant differential regulation of immune mediators like matrix metalloproteinase 3, interleukin 1 and interleukin 17. We conclude that STb can play a prominent role in ETEC-induced secretion and early immune response. In three pigs, 6 different treatments were performed. These treatments consisted of 4 mutant enterotoxigenic Escherichia coli GIS26 strains, GIS26 wild type strain, or PBS control. Per pig, the small intestine was divided into 6 loops with an interloop in between to avoid cross-contamination. In conclusion, every pig received each of the 6 treatments ad random.

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Expression data of enterotoxigenic (ETEC) isolate E24377A

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