Journal of Food Processing & Technology

Membrane fluidity and acid stress regulate the Listeria monocytogenes FoF1ATPase

International Conference on Food Safety and Regulatory Measures

August 17-19, 2015 Birmingham, UK

Thomas J Montville, Ph.D., F.A.A.M., F.I.F.T.

Rutgers, the State University of New Jersey, New Brunswick, NJ, 08902, USA

Posters-Accepted Abstracts: J Food Process Technol

Abstract:

Listeria monocytogenes can grow or survive in the cold, adapt to conditions of acid stress and of low water activity, making them difficult to control. A spontaneous L. monocytogenes nisin-resistant mutant had increased acid sensitivity and altered membrane fluidity which correlated to an increased activity of its FoF1ATPase (Vmax was 2- fold greater than for the wild-type strain). Cells demonstrating decreased acid sensitivity had less ATPase c-subunit abundance further implicating a role for the FoF1ATPase. These findings led to a hypothesis linking membrane fluidity to FoF1ATPase activity. Regulation at the level of transcription was also investigated. Transcriptional analysis using real-time PCR, suggested that transcription of the atpE gene, encoding for the c-subunit is much lower in the mutant than in the wild-type, and is down-regulated by acid stress. However, because the nine genes encoding for the ATPase subunits are transcribed as part of a polycistronic operon, the possibility of post-transcriptional regulation cannot be overlooked. The cumulative results from our research paint a complex picture of L. monocytogenesâ?? response to different stressors, which allows this ubiquitous organism to respond rapidly to the diverse adverse conditions it encounters in food.

Biography :

Email: montville@SEBS.Rutgers.edu