Characterization of germination and outgrowth of sorbic acid-stressed Bacillus cereus ATCC 14579 spores: Phenotype and transcriptome analysis

• Published in: Food microbiology Vol. 28; no. 2; pp. 275 - 283
• Main Authors: van Melis, C.C.J., Nierop Groot, M.N., Tempelaars, M.H., Moezelaar, R., Abee, T.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2011; Elsevier
• Subjects: Bacillus cereus; Bacillus cereus - drug effects; Bacillus cereus - physiology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; cold-shock; Culture Media; Dose-Response Relationship, Drug; Flow Cytometry; Food Contamination - analysis; Food Contamination - prevention & control; Food industries; Food Microbiology; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; genes; Germination; gram-positive bacteria; Hydrogen-Ion Concentration; identification; inhibition; membrane; Microarray; Microarray Analysis; Organic acid; organic-acids; Phenotype; Sorbic acid; Sorbic Acid - pharmacology; Species Specificity; Spores, Bacterial - genetics; Spores, Bacterial - growth & development; Spores, Bacterial - metabolism; Sporulation; Stress; subtilis spores; vegetative cells; Bacillus cereus; Sporulation; Germination; Organic acid; Microarray; Sorbic acid; Stress; Bacillaceae; Organic acids; Spores; Characterization; Phenotype; Bacillales; Bacteria
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2010.04.005

Sorbic acid (SA) is widely used as a preservative, but the effect of SA on spore germination and outgrowth has gained limited attention up to now. Therefore, the effect of sorbic acid on germination of spores of Bacillus cereus strain ATCC 14579 was analyzed both at phenotype and transcriptome level. Spore germination and outgrowth were assessed at pH 5.5 without and with 0.75, 1.5 and 3.0 mM (final concentrations) undissociated sorbic acid (HSA). This resulted in distinct HSA concentration-dependent phenotypes, varying from reduced germination and outgrowth rates to complete blockage of germination at 3.0 mM HSA. The phenotypes reflecting different stages in the germination process could be confirmed using flow cytometry and could be recognized at transcriptome level by distinct expression profiles. In the absence and presence of 0.75 and 1.5 mM HSA, similar cellular ATP levels were found up to the initial stage of outgrowth, suggesting that HSA-induced inhibition of outgrowth is not caused by depletion of ATP. Transcriptome analysis revealed the presence of a limited number of transcripts in dormant spores, outgrowth related expression, and genes specifically associated with sorbic acid stress, including alterations in cell envelope and multidrug resistance. The potential role of these HSA-stress associated genes in spore outgrowth is discussed.