title: Secretome analysis of diarrhea-inducing strains of Escherichia coli.
abstract: Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by Gram-negative bacteria. Enterohemorrhagic Escherichia coli, O157:H7, is the major pathogen often causing outbreaks. However, studies have reported that the significant outbreaks caused by non-O157:H7 E. coli strains, also known as "Big-Six" serogroup strains, are increasing. There is no systematic study describing differential secreted proteins from these non-O157:H7 E. coli strains. In this study, we carried out MS-based differential secretome analysis using tandem mass tags labeling strategy of non-O157:H7 E. coli strains, O103, O111, O121, O145, O26, and O45. We identified 1241 proteins, of which 565 proteins were predicted to be secreted. We also found that 68 proteins were enriched in type III secretion system and several of them were differentially expressed across the strains. Additionally, we identified several strain-specific secreted proteins that could be used for developing potential markers for the identification and strain-level differentiation. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli Big-Six serogroup and the several of these strain-specific secreted proteins can be further studied to develop potential markers for identification and strain-level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and detection and identification of bio threats in biodefense.
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore, India.|Centre for Bioinformatics, Pondicherry University, Puducherry, India.|McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Raja Sekhar
authors.initials: RS
authors.lastname: Nirujogi
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore, India.
authors.forename: Babylakshmi
authors.initials: B
authors.lastname: Muthusamy
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.|Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, South Korea.
authors.forename: Min-Sik
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore, India.|Manipal University, Madhav Nagar, Manipal, India.
authors.forename: Gajanan J
authors.initials: GJ
authors.lastname: Sathe
authors.affiliation: Centre for Bioinformatics, Pondicherry University, Puducherry, India.
authors.forename: P T V
authors.initials: PT
authors.lastname: Lakshmi
authors.affiliation: Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Olga N
authors.initials: ON
authors.lastname: Kovbasnjuk
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore, India.|Centre for Bioinformatics, Pondicherry University, Puducherry, India.|Manipal University, Madhav Nagar, Manipal, India.|NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neuro Sciences, Bangalore, India.|YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, India.
authors.forename: T S Keshava
authors.initials: TS
authors.lastname: Prasad
authors.affiliation: Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Wade
authors.affiliation: Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA.
authors.forename: Rabih E
authors.initials: RE
authors.lastname: Jabbour
mesh_terms: D058947:Bacterial Secretion Systems; D016000:Cluster Analysis; D003967:Diarrhea / Q000382:microbiology*; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005110:Extracellular Space / Q000737:chemistry; D013058:Mass Spectrometry; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*
chemical_list: D058947:Bacterial Secretion Systems; D029968:Escherichia coli Proteins; D020543:Proteome
keywords: Escherichia coli; Mass spectrometry; Proteomics; Secretome