Investigating the role of prophage excision in bacterial motility and sporulationToman Drinovec, Zeta (Avtor) Dragoš, Anna Magdalena (Mentor) Vesel Gallay, Nina (Komentor) temperate bacteriophagesregulatory switchsporulationswarmingBacillus subtilisSpbetavirusTemperate bacteriophages (phages) have a complex impact on bacterial communities, reducing the host population due to lytic cycle induction or providing competitive advantage by introducing their accessory genes. Furthermore, phages known as regulatory switches also function as gene regulators. When necessary, prophage excision takes place, allowing for attachment gene reconstitution and expression, while simultaneously not triggering the lytic cycle. Even though this behaviour has been described in several phages, including SPbetaviruses SPβ and phi3T, known to excise during sporulation, little is known about regulatory switching under different conditions or by other phages of the genus. As preliminary data suggested impaired swarming in a kamA mutant strain, we focused on investigating how inducing those processes relates to regulatory excision of phi3T and goe11 prophages. To determine the role of attachment gene kamA in surface motility and monitor its expression, kamA deletion mutants and new fluorescent reporter strains were constructed. Gene kamA expression was tracked during swarming and sporulation with the use of fluorescent transcriptional reporter strains. Quantification of excision was determined by qPCR in different time-points under sporulation conditions. To differentiate spontaneous induction from regulatory excision, plaque assay was performed at the same time-points. No direct link between swarming and kamA expression could be confirmed, however certain constructs with kamA disruption showed swarming impairment. It was shown that kamA expression does not occur during swarming, while in sporulation it differs upon cultivation in NSM and LB media, which also impacts the temporal dynamics of regulatory excision of phi3T and goe11, respectively. While the novel characterization of goe11 as a regulatory switch contributes to the understanding of complex phage-host interactions, the possible role of kamA in swarming will have to be further investigated.[Z. Toman Drinovec]20262026-09-06 08:16:25Magistrsko delo/naloga186891UDK: 579.25:578.347VisID: 287185COBISS_ID: 290136067sl