Safiya Alvi, Denise Mondelo and Justin Gejo

Abstract:

Many laboratory-adapted strains of bacteria display diminished capacity to perform certain biological processes, including biofilm formation and swarming. The bacterial species Bacillus subtilis was cultured for 300 generations in a laboratory setting to produce a laboratory-adapted isolate, SH2. This variant displayed reduced biofilm formation and swarming ability, in conjunction with the development of multicellular, spherical aggregates. A point mutation in the gene hag was analyzed and identified as being both necessary and sufficient for the formation of these aggregates. However, further investigation is required to determine how properties of the flagella contribute to certain characteristics of the aggregates, such as their spherical shape and size. Does aggregation occur because the mutant Hag proteins create stickier flagella, or does aggregation occur because the disordered flagella get tangled, or do both things contribute? Bacterial flagella serve as rotational propellers composed of multiple structural proteins, including proton channels MotA/B and basal body rotor protein FLiG. MotA and MotB form proton channels that generate force for flagellar rotation. The FliG protein forms a ring-like structure responsible for direction and interacts with MotA to generate flagellar force. We have paralyzed mutant and WT flagella by deleting the motA, motB, or fliG genes and are using these strains to identify whether flagellar rotation contributed to the formation of spherical aggregates.