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Proteomic analysis of Lactobacillus casei GCRL163 cell-free extracts reveals a SecB homolog and other biomarkers of prolonged heat stress

Citation

Adu, KT and Wilson, R and Nichols, DS and Baker, AL and Bowman, JP and Britz, ML, Proteomic analysis of Lactobacillus casei GCRL163 cell-free extracts reveals a SecB homolog and other biomarkers of prolonged heat stress, PLoS One, 13, (10) Article e0206317. ISSN 1932-6203 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 Adu et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1371/journal.pone.0206317

Abstract

Prolonged heat stress is one of the harsh conditions Lactobacillus casei strains encounter as non-starter lactic acid bacteria in dairy product manufacture. To understand the physiological and molecular mechanisms through which Lb. casei GCRL163 adapts to persistent elevated temperature, label-free quantitative proteomics of cell-free extracts was used to characterize the global responses of the strain cultured anaerobically in bioreactors at 30 to 45C, pH 6.5, together with GC-MS for fatty acid methyl ester analysis at different growth phases. At higher growth temperatures, repression of energy-consuming metabolic pathways, such as fatty acid, nucleotide and amino acid biosynthesis, was observed, while PTS- and ABC-type transporter systems associated with uptake of nitrogen and carbon sources were up-regulated. Alkaline shock protein Asp23_2 was only detected at 45C, expressed at high abundance, and presumptive α-L-fucosidase only at 40 and 45C, with highly increased abundance (log2-fold change of 7) at 45C. We identified a novel SecB homolog as a protein export chaperone putatively involved in posttranslational translocation systems, which was down-regulated as growth temperature increased and where the modelled 3D-structure shared architectural similarities with the Escherichia coli SecB protein. Membrane lipid analyses revealed temporal changes in fatty acid composition, cyclization of oleic acid to cyclopropane and novel cyclopentenyl moieties, and reduced synthesis of vaccenic acid, at higher temperatures. An 18kDa α-crystallin domain, Hsp20 family heat shock protein was more highly up-regulated in response to heat stress compared to other molecular chaperones, suggesting this protein could be a useful biomarker of prolonged heat stress in Lb. casei GCRL163.

Item Details

Item Type:Refereed Article
Keywords:thermal stress, heat shock response, protein metabolism, protein expression, chaperone proteins
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Bacteriology
Objective Division:Manufacturing
Objective Group:Dairy Products
Objective Field:Dairy Products not elsewhere classified
UTAS Author:Adu, KT (Mr Kayode Adu)
UTAS Author:Wilson, R (Dr Richard Wilson)
UTAS Author:Nichols, DS (Dr David Nichols)
UTAS Author:Baker, AL (Dr Anthony Baker)
UTAS Author:Bowman, JP (Associate Professor John Bowman)
UTAS Author:Britz, ML (Professor Margaret Britz)
ID Code:128934
Year Published:2018
Deposited By:TIA - Research Institute
Deposited On:2018-10-26
Last Modified:2019-03-21
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