The regulatory roles of ComK proteins in Bacillus cereus and other Bacilli

PhD ceremony: Ms. A.M. Mironczuk, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: The regulatory roles of ComK proteins in Bacillus cereus and other Bacilli

Promotor(s): prof. O.P. Kuipers

Faculty: Mathematics and Natural Sciences

The research described in the thesis of Aleksandra Mirończuk was initiated to investigate competence development in B. cereus to understand the evolution and function of the putative competence machinery in Bacilli species. In addition, the roles of ComK proteins in B. cereus were investigated.

Bacteria are small, single-cell organisms that need to survive in rapidly changing environmental conditions. It often occurs that only part of the bacterial population develops survival strategies such as spore or biofilm formation or genetic competence. Genetic competence is the ability to undergo genetic transformation: a process that involves the acquisition of naked DNA form the extracellular environment. Competence development has been described for variety bacteria species, both for Gram negative and Gram positive. In most of these species competence development is a physiological state controlled by a specific regulon, involving quorum sensing and responses to nutrition limitations. The elucidation of the molecular mechanisms by Mirończuk that are involved in this process can lead to create useful biotechnological tools, which can be used for easy genetic engineering of B. cereus and other “non-transformable” species. Her work shows that species previously not known to be naturally transformable, indeed possess a functional competence machinery and under given conditions are able to take up exogenous DNA.