The global proteomic responses of the foodborne pathogen Listeria monocytogenes strain Scott A, during active growth and transition to the stationary growth phase under progressively more acidic conditions, created by addition of lactic acid and HCl, were investigated using label-free liquid chromatography/tandem mass spectrometry. Approximately 56% of the Scott A proteome was quantitatively assessable, and the data provides insight into its acquired acid tolerance response (ATR) as well as the relation of the ATR to the growth phase transition. Alterations in protein abundance due to acid stress were focused in proteins belonging to the L.monocytogenes common genome, with few strain-dependent proteins involved. However, one of the two complete prophage genomes appeared to enter lysogeny. During progressive acidification, the growth rate and yield were reduced 55% and 98%, respectively, in comparison to nonacidified control cultures. The maintenance of the growth rate was determined to be connected to activation of cytoplasmic pH homeostatic mechanisms while cellular reproductive-related and cell component turnover proteins were markedly more abundant in acid stressed cultures. Cell biomass accumulation was impeded predominantly due to repression of phosphodonorlinked enzymes involved with sugar phosphotransfer, glycolysis, and cell wall polymer biosynthesis. Acidification caused a shift from heterofermentation to an oxidatively stressed state in which ATP appears to be generated mainly through the pyruvate dehydrogenase/pyruvate oxidase/phosphotransacetylase/acetate kinase and ranched chain acid dehydrogenase pathways. Analysis of regulons indicated energy conservation occurs due to repression by the GTP/isoleucine sensor CodY and also the RelA mediated stringent response. Whole proteome analysis proved to be an effective way to highlight proteins involved with the acquisition of the ATR.

Item Type:	Refereed Article
Keywords:	label-free, proteomics, multidimensional, Listeria monocytogenes, acid stress, growth phase
Research Division:	Biological Sciences
Research Group:	Biochemistry and cell biology
Research Field:	Proteomics and intermolecular interactions (excl. medical proteomics)
Objective Division:	Health
Objective Group:	Public health (excl. specific population health)
Objective Field:	Food safety
UTAS Author:	Bowman, JP (Associate Professor John Bowman)
UTAS Author:	Hages, E (Ms Esta Kokkoris)
UTAS Author:	Nilsson, RE (Mr Rolf Nilsson)
UTAS Author:	Kocharunchitt, C (Dr Jay Kocharunchitt)
UTAS Author:	Ross, T (Professor Tom Ross)
ID Code:	77410
Year Published:	2012
Web of Science® Times Cited:	25
Deposited By:	Agricultural Science
Deposited On:	2012-04-11
Last Modified:	2015-07-30
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