The Effect Of Chemotaxis On The Swarming Ability Of Bacillus Subtilis Critical Effect Of Glutamic Acid And Lysine

Abstract Bacterial cells differentiation constitutes an appropriate and efficient way to respond to an ever-changing environment. Bacillus subtilis are no different where in some conditions planktonic cells differentiate into highly motile swarmer cells. The hyperflagellated swarmer cells located usually at the colony edge move in a cooperative manner in order to reconnoiter new sites for colonization this movement is called swarming. The chemotaxis proteins take a part of several factors playing an essential role in swarmer differentiation hence migration therefore we assumed a connection between chemotaxis and swarming profile of B. subtilis. To this end we examined the effect of amino acids chemoattractants glutamic acid and lysine deprivation on the capability of swarming. Here we show that deprivation of synthetic B-media from glutamic acid result on attenuated defective and random swarming pattern deprivation of lysine lead to an almost normal swarming pattern meanwhile double deprivation of both amino acids result in important reduction of swarming capability. Moreover we developed a method to screen the chemotaxis clearly using swarm plates with concentration gradient. Using this approach we found that B. subtilis manage to swarm completely toward glutamic acid and didnt swarm toward medium lacking this amino acid meanwhile the bacteria manage to swarm in all sides of plates with concentration gradient of lysine. Furthermore our results indicate that these two chemoattractants can reduce the motility by modulating the expression of hag gene. The absence of glutamic acid and lysine decrease the expression of hag during swarming respectively for 36 and 15.