title: Analysis and Characterization of Proteins Associated with Outer Membrane Vesicles Secreted byCronobacterspp.
abstract: Little is known about secretion of outer membrane vesicles (OMVs) byCronobacter. In this study, OMVs isolated fromCronobacter sakazakii, Cronobacter turicensis, andCronobacter malonaticuswere examined by electron microscopy (EM) and their associated outer membrane proteins (OMP) and genes were analyzed by SDS-PAGE, protein sequencing, BLAST, PCR, and DNA microarray. EM of stained cells revealed that the OMVs are secreted as pleomorphic micro-vesicles which cascade from the cell's surface. SDS-PAGE analysis identified protein bands with molecular weights of 18 kDa to >100 kDa which had homologies to OMPs such as GroEL; OmpA, C, E, F, and X; MipA proteins; conjugative plasmid transfer protein; and an outer membrane auto-transporter protein (OMATP). PCR analyses showed that most of the OMP genes were present in all sevenCronobacterspecies while a few genes (OMATP gene,groEL, ompC, mipA, ctp, andompX) were absent in some phylogenetically-related species. Microarray analysis demonstrated sequence divergence among the OMP genes that was not captured by PCR. These results support previous findings that OmpA and OmpX may be involved in virulence ofCronobacter, and are packaged within secreted OMVs. These results also suggest that other OMV-packaged OMPs may be involved in roles such as stress response, cell wall and plasmid maintenance, and extracellular transport.
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Mahendra H
authors.initials: MH
authors.lastname: Kothary
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Gopal R
authors.initials: GR
authors.lastname: Gopinath
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Gangiredla
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Prasad V
authors.initials: PV
authors.lastname: Rallabhandi
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Harrison
authors.affiliation: Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, WHO Collaborating Centre for Cronobacter, University College, Dublin Dublin, Ireland.
authors.forename: Qiong Q
authors.initials: QQ
authors.lastname: Yan
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Hannah R
authors.initials: HR
authors.lastname: Chase
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Boram
authors.initials: B
authors.lastname: Lee
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Eunbi
authors.initials: E
authors.lastname: Park
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: YeonJoo
authors.initials: Y
authors.lastname: Yoo
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Taejung
authors.initials: T
authors.lastname: Chung
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Finkelstein
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Flavia J
authors.initials: FJ
authors.lastname: Negrete
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Isha R
authors.initials: IR
authors.lastname: Patel
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Laurenda
authors.initials: L
authors.lastname: Carter
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Sathyamoorthy
authors.affiliation: Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, WHO Collaborating Centre for Cronobacter, University College, Dublin Dublin, Ireland.
authors.forename: Séamus
authors.initials: S
authors.lastname: Fanning
authors.affiliation: U. S. Food and Drug Administration Laurel, MD, USA.
authors.forename: Ben D
authors.initials: BD
authors.lastname: Tall
keywords: EM; PCR; microarray; outer membrane proteins; outer membrane vesicles