title: Prediction of Bacillus weihenstephanensis acid resistance: the use of gene expression patterns to select potential biomarkers.
abstract: Exposure to mild stress conditions can activate stress adaptation mechanisms and provide cross-resistance towards otherwise lethal stresses. In this study, an approach was followed to select molecular biomarkers (quantitative gene expressions) to predict induced acid resistance after exposure to various mild stresses, i.e. exposure to sublethal concentrations of salt, acid and hydrogen peroxide during 5 min to 60 min. Gene expression patterns of unstressed and mildly stressed cells of Bacillus weihenstephanensis were correlated to their acid resistance (3D value) which was estimated after exposure to lethal acid conditions. Among the twenty-nine candidate biomarkers, 12 genes showed expression patterns that were correlated either linearly or non-linearly to acid resistance, while for the 17 other genes the correlation remains to be determined. The selected genes represented two types of biomarkers, (i) four direct biomarker genes (lexA, spxA, narL, bkdR) for which expression patterns upon mild stress treatment were linearly correlated to induced acid resistance; and (ii) nine long-acting biomarker genes (spxA, BcerKBAB4_0325, katA, trxB, codY, lacI, BcerKBAB4_1716, BcerKBAB4_2108, relA) which were transiently up-regulated during mild stress exposure and correlated to increased acid resistance over time. Our results highlight that mild stress induced transcripts can be linearly or non-linearly correlated to induced acid resistance and both approaches can be used to find relevant biomarkers. This quantitative and systematic approach opens avenues to select cellular biomarkers that could be incremented in mathematical models to predict microbial behaviour.
authors.affiliation: ADRIA Développement, UMT 08.3 PHYSI'Opt, Z.A. de Creac'h Gwen, F-29196 Quimper cedex, France; Université de Brest, EA3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT 08.3 PHYSI'Opt, IFR148 ScInBioS, 6 rue de l'Université, F-29334 Quimper, France. Electronic address: noemie.desriac@adria.tm.fr.
authors.forename: N
authors.initials: N
authors.lastname: Desriac
authors.forename: F
authors.initials: F
authors.lastname: Postollec
authors.forename: L
authors.initials: L
authors.lastname: Coroller
authors.forename: D
authors.initials: D
authors.lastname: Sohier
authors.forename: T
authors.initials: T
authors.lastname: Abee
authors.forename: H M W
authors.initials: HM
authors.lastname: den Besten
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects; D001407:Bacillus / Q000187:drug effects* / Q000235:genetics*; D015415:Biomarkers / Q000032:analysis*; D005516:Food Microbiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000143:Acids; D015415:Biomarkers; D012965:Sodium Chloride; D006861:Hydrogen Peroxide
keywords: Acid resistance; Bacillus; Biomarker; Food safety; Gene expression; Modelling