Exploring the role of Bacillus subtilis gene kamA controlled by a phage regulatory switchKračman, Filip (Avtor) Dragoš, Anna Magdalena (Mentor) lysogenic bacteriophagesphage regulatory-switchbacteriophage resistanceBacillus subtilisgene kamABacillus subtilis is a model organism for studying Gram-positive microorganisms; its kamA gene can be interrupted by the inserted lysogenic phage phi3T, closely related to SPbeta which was shown to act as a phage regulatory switch regulating the expression of the spsM gene during sporulation. This thesis explores the possible antiviral activity of the kamA gene product based on similarity of its 3D structure with three viperins, a class of antiviral proteins found across the tree of life. This possible role was tested by performing multiple double-layer plaque assays, susceptibility assays in liquid cultures and a phage adsorption assay comparing B. subtilis strain PY79 and its ∆kamA and ∆spsM mutants. Results revealed that a deletion of kamA decreases susceptibility of B. subtilis to lytic phage Nf, rather than the hypothesised viperin-like activity of its gene product. Furthermore, deletion of the gene exhibits an effect on the rate of phage adsorption resulting in a trend distinct from cells with an intact gene, However, due to an unforeseen phenomenon affecting this experiment, we cannot say this with certainty. As kamA harbours an attachment site for phage phi3T which effectively has a deleterious effect, these findings demonstrate a way in which lysogenic phages may confer protection towards lytic phages.[F. Kračman]20242024-10-13 07:15:41Magistrsko delo/naloga163849sl