title: The CLO3403/CLO3404 two-component system of Clostridium botulinum E1 Beluga is important for cold shock response and growth at low temperatures.
abstract: In order to survive a temperature downshift, bacteria have to sense the changing environment and adjust their metabolism and structure. Two-component signal transduction systems (TCSs) play a central role in sensing and responding to many different environmental stimuli. Although the nonproteolytic (group II) Clostridium botulinum represents a major hazard in chilled foods, the cold adaption mechanisms of group II C. botulinum organisms are not known. Here, we show that the CLO3403/CLO3404 TCS of C. botulinum E1 Beluga is involved in the cold shock response and growth at 12°C. Cold shock induced the expression of the genes encoding the histidine kinase (clo3403) and the response regulator (clo3404) by more than 100-fold after 5 h relative to their expression in a nonshocked culture at the corresponding time point. The involvement of CLO3403/CLO3404 in growth at low temperature was demonstrated by impaired growth of the insertional clo3403 and clo3404 knockout mutants at 12°C compared to the growth of the wild-type culture. Additionally, the inactivation of clo3403 had a negative effect on motility. The growth efficiency at 12°C of the TCS mutants and the motility of the kinase mutants were restored by introducing a plasmid harboring the operon of the CLO3403/CLO3404 TCS. The results suggest that the CLO3403/CLO3404 TCS is important for the cold tolerance of C. botulinum E1 Beluga.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Gerald
authors.initials: G
authors.lastname: Mascher
authors.forename: Yagmur
authors.initials: Y
authors.lastname: Derman
authors.forename: David G
authors.initials: DG
authors.lastname: Kirk
authors.forename: Eveliina
authors.initials: E
authors.lastname: Palonen
authors.forename: Miia
authors.initials: M
authors.lastname: Lindström
authors.forename: Hannu
authors.initials: H
authors.lastname: Korkeala
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003014:Clostridium botulinum / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects*; D058639:Cold-Shock Response; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D000071677:Histidine Kinase; D016254:Mutagenesis, Insertional; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase