Elucidating the MolecularMechanism Involved inIntra-specific Competition ofBacillus cereus MSM-S1

Bacteria in the wild can be exposed to harsh conditions like lack of nutrients, overcrowding, limited space and extreme environment. In response to such stresses, bacteria show radical behavior, including competition between bacterial species. In interspecific competition between two different bacterial species, one usually have an advantage over the other based on differences in growth rates, motility and ability to produce antibacterial agents or toxins. But, intraspecific competition between two colonies, having the same capabilities, makes the competition more interesting to study to understand survival strategies in bacteria. Sibling bacterial colonies of Bacillus cereus MSM-S1 when inoculated on the same nutrient-agar plate inhibit growth of each other at the interacting zone in between them, establishing a zone of inhibition. The colonies were exposed to different challenges like increased agar and salinity to study the nature of inhibition. We observed significant changes in colony growth, cell- and colony morphology at the interacting zones as compared to the non-interacting zones. Gene expression pattern and protein expression pattern in bacteria collected from competing sibling colonies were also studied and compared between interacting zone and non-interacting zone in different agar and salt concentrations.