**6.2 Swarming motility and biofilm formation assays**

Swarming and biofilm formation are other quorum sensing controlled processes seen in bacteria such as P. aeruginosa [139], S. marcescens [140], P. mirabilis [6] and are known to play a major role in pathogenesis. Reduction in diameter of the swarm zone, alteration in swarming patterns and significant reduction in biofilm formation [141] indicate that given compound has AQS activity. While reduction in swarm zone diameter and alteration of swarming patterns can be quantified directly, inhibition in biofilm formation can be quantified using microtiter plate method and observing topographical changes in biofilm by scanning electron microscopy [125] as well as confocal laser scanning microscopy. Wijaya et al., have reported that crude extracts from marine actinobacteria isolated from Indonesia, show significant reduction of biofilm formation by inhibiting quorum sensing in Gram positive and Gram negative pathogenic bacteria [142]. Similar activity is reported in extracts from Nocardiopsis sp [143].
