Biofilm formation as microbial development

Biofilms can be defined as communities of microorganisms attached to a surf ace. It is clear that microorganisms undergo profound changes during their transition from planktonic (free-swimming) organisms to cells that are part of a complex, surface-attached community. These changes are reflected in t he new phenotypic characteristics developed by biofilm bacteria and occur i n response to a variety of environmental signals. Recent genetic and molecu lar approaches used to study bacterial and fungal biofilms have identified genes and regulatory circuits important for initial cell-surface interactio ns, biofilm maturation, and the return of biofilm microorganisms to a plank tonic mode of growth. Studies to date suggest that the planktonic-biofilm t ransition is a complex and highly regulated process. The results reviewed i n this article indicate that the formation of biofilms serves as a new mode l system for the study of microbial development.