Effects of Growth Phase and Temperature onσBActivity within aListeria monocytogenesPopulation: Evidence for RsbV-Independent Activation ofσBat Refrigeration Temperatures

Autor: Eoin Cosgrave, Conor P. O'Byrne, Marta Utratna, Rhodri Ceredig, Claas Baustian
Rok vydání: 2014
Předmět:
Zdroj: BioMed Research International. 2014:1-11
ISSN: 2314-6141
2314-6133
DOI: 10.1155/2014/641647
Popis: The alternative sigma factorσBofListeria monocytogenesis responsible for regulating the transcription of many of the genes necessary for adaptation to both food-related stresses and to conditions found within the gastrointestinal tract of the host. The present study sought to investigate the influence of growth phase and temperature on the activation ofσBwithin populations ofL.monocytogenesEGD-e wild-type, ΔsigB,and ΔrsbVthroughout growth at both 4°C and 37°C, using a reporter fusion that couples expression of EGFP to the stronglyσB-dependent promoter oflmo2230. A similarσBactivation pattern within the population was observed in wt-egfpat both temperatures, with the highest induction ofσBoccurring in the early exponential phase of growth when the fluorescent population rapidly increased, eventually reaching the maximum in early stationary phase. Interestingly, induction ofσBactivity was heterogeneous, with only a proportion of the cells in the wt-egfppopulation being fluorescent above the background autofluorescence level. Moreover, significant RsbV-independent activation ofσBwas observed during growth at 4°C. This result suggests that an alternative route toσBactivation exists in the absence of RsbV, a finding that is not explained by the current model forσBregulation.
Databáze: OpenAIRE