PhD defence

Bacterial Stress Management: Novel roles of SigB in the Bacillus general stress response

PhD candidate KY (Claire) Yeak MSc
External promotor Prof. Dr. Tjakko Abee
External copromotor Dr. Marjon Wells-Bennik
Organisation Wageningen University, Food Microbiology Laboratory

Tue 25 October 2022 13:30 to 15:00

Venue Omnia
Room Groot Auditorium


Bacteria are present ubiquitously in our environment. They can encounter strongly fluctuating conditions that may be challenging for survival and growth, such as heat and cold, or a lack of nutrients (starvation). As a countermeasure, various bacterial species including the group of bacteria known as Bacillus, respond to these stresses using a robust stress management strategy, the so-called general stress response (GSR). GSR is controlled by the master regulator of stress (a protein called SigB).

The work described in this thesis investigated the GSR of three Bacillus members (Bacillus subtilis, Bacilluslicheniformis, and Bacillus cereus)upon exposure to different types of stresses, and the new roles of SigB in controlling stress defense and other cellular processes in these species. This stress management strategy was examined further and new roles of SigB were discovered by analyzing DNA sequences of these bacteria and their responses under stressed or non-stressed conditions. The fundamental knowledge gained in this research provides a deeper understanding of stress adaptation mechanisms in these Bacillus species which may cause food spoilage or foodborne disease. Such knowledge can have practical implications for further improvement of food processing and preservation strategies.

Work done at NIZO, Ede, and project funded by the European Union’s Horizon 2020 Program, Marie Skłodowska-Curie grant agreement No 721456