title: Identification of CdnL, a Putative Transcriptional Regulator Involved in Repair and Outgrowth of Heat-Damaged Bacillus cereus Spores.
abstract: Spores are widely present in the environment and are common contaminants in the food chain, creating a challenge for food industry. Nowadays, heat treatments conventionally applied in food processing may become milder to comply with consumer desire for products with higher sensory and nutritional values. Consequently subpopulations of spores may emerge that are sublethally damaged rather than inactivated. Such spores may germinate, repair damage, and eventually grow out leading to uncontrolled spoilage and safety issues. To gain insight into both the behaviour of damaged Bacillus cereus spores, and the process of damage repair, we assessed the germination and outgrowth performance using OD595 measurements and microscopy combined with genome-wide transcription analysis of untreated and heat-treated spores. The first two methods showed delayed germination and outgrowth of heat-damaged B. cereus ATCC14579 spores. A subset of genes uniquely expressed in heat-treated spores was identified with putative roles in the outgrowth of damaged spores, including cdnL (BC4714) encoding the putative transcriptional regulator CdnL. Next, a B. cereus ATCC14579 cdnL (BC4714) deletion mutant was constructed and assessment of outgrowth from heat-treated spores under food relevant conditions showed increased damage compared to wild type spores. The approach used in this study allows for identification of candidate genes involved in spore damage repair. Further identification of cellular parameters and characterisation of the molecular processes contributing to spore damage repair may provide leads for better control of spore outgrowth in foods.
authors: TI Food and Nutrition, Wageningen, The Netherlands.|Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands.|Wageningen UR Food & Biobased Research, Wageningen, The Netherlands.
authors: Alicja K
authors: AK
authors: Warda
authors: Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands.
authors: Marcel H
authors: MH
authors: Tempelaars
authors: TI Food and Nutrition, Wageningen, The Netherlands.|NIZO Food Research B.V., Ede, The Netherlands.
authors: Jos
authors: J
authors: Boekhorst
authors: TI Food and Nutrition, Wageningen, The Netherlands.|Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands.
authors: Tjakko
authors: T
authors: Abee
authors: TI Food and Nutrition, Wageningen, The Netherlands.|Wageningen UR Food & Biobased Research, Wageningen, The Netherlands.
authors: Masja N
authors: MN
authors: Nierop Groot
mesh_terms: D001409:Bacillus cereus / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D017353:Gene Deletion; D006358:Hot Temperature; D013171:Spores, Bacterial / Q000235:genetics / Q000254:growth & development; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors