sentence: Since expression of adhesion factors is also positively regulated by c-di-GMP [ 40 ] , elevated c-di-GMP level enhances adhesion of the tpbA mutant.c-di-GMP seems to control the switch of motility-sessility of the tpbA mutant since inactivation of TpbA abolished swarming motility ( Fig. 2A ) and decreased swimming motility by 40 % ( Fig. 2B ) , although regulation of swarming motility is very complex as its activity is controlled by QS , flagellar synthesis , and production of rhamnolipids [ 42 ] .