Development of Chemical Substances Regulating Biofilm Formation.

The chemical substances which regulate biofilm formation were examined, and a bioassay system which uses marine bacteria with adhering properties was developed. This bioassay system is suitable for screening crude extracts from marine organisms. Using this system, those substances which regulate biofilm formation were isolated from marine organisms. For example, bis(deacetyl)solenolide D was obtained from the marine sponge Psammaplysilla purpurea. Novel nitroalkanes were also isolated from the Okinawan sponge Callyspongia sp. Ethyl N-(2-phenylethyl)carbamate isolated from the marine bacteria SCRC3P79 (Cytophaga sp.) inhibited biofilm formation. Furthermore, the N,N-dichloro, isocyanide, isothiocyanate, and dithiocarbamate derivatives of 2-(4-nitrophenyl)ethylamine, significantly inhibited the growth of marine attaching bacteria. Interestingly, most of the marine sponges examined contained anti-biofilm compounds, such as benzoic acid, aeroplysinin-I, and bromoageliferin.