Microorganisms predominantly exist in sessile communities rather than as free-living planktonic cells. The bacteria in these sessile communities, which develop on all surfaces in aqueous environments, organise themselves in complex surface attached micro-colonies, and undergo cellular differentiation as part of a highly evolved development program. Such differentiated surface localised communities, in which bacterial cells are embedded in a macromolecular matrix, are called biofilms. An increased understanding of biofilm differentiation and development programs in bacteria has several profound implications:

(i) There are similarities between biofilm formation and development in "single cell" prokaryotes and higher multicellular bacteria, such as those with fruiting bodies and spore formation. (J.S. Webb et al 2003, Prochnow et al 2003 (submitted)). Cell-cell signaling may involve high density dependant autoinduction systems for the coordination of genes involved in colonization, differentiation and virulence (S.Kjelleberg & Molin 2002, Hentzer et al 2003, Hentzer et al 2002, Labbate et al 2003). Such quorum sensing systems (QSS) are employed by a large number of bacteria. Studies of bacterial biofilms will dramatically increase our understanding of cell-cell signaling systems and of differentiation in multicellular organisms.

The CMBB supports several research projects on biofilm formation by environmentally as well as medically relevant bacteria.

assessment of the precise roles of QSS in the temporal and spatial expression of signal controlled genes
cellular differentiation
poptosis
ageing and dispersal of biofilm cells.

(ii) Most ecological studies have focused on free-living bacteria and there is a dearth of information on the ecological role of bacteria in biofilms.

The CMBB runs an extensive program on the role of surface colonizing bacteria on marine plants and sessile animals. The program addresses the extent of microbial diversity in the environment, identification of novel communication systems and bioactives and the role of bacteria in defending higher organisms against unwanted colonization and the establishment of pathogens.

(iii) The protective role of biofilms against conventional antimicrobial treatments presents significant problems in industry and in the treatment of bacterial infections. Several basic research projects as well as applied R and D ventures for novel antibiofilm treatments have been initiated.

The CMBB has developed advanced quorum sensing blocking technologies, following the identification of effective marine QSBs and structure function based optimization of lead compounds (e.g. Manefield et al 1999, Manefield et al 2001, Hentzer et al 2003, Givskov et al 1996, Maximillien et al 1998).