Clonal Fitness of Attached Bacteria Predicted by Analog Modeling

Microbial ecology is undergoing a revolution of phenomenological discoveries and methodological advances that bring resolution down toward the level of the individual and highlight the role of chemical exchanges in bacterial communities. Recent work shows that inter- and intraspecific chemical signaling, leading to coordinated, density-dependent behavior (termed quorum sensing) (Fuqua et al. 1994), is commonplace among bacterial species (Fuqua et al. 1996, Kaiser and Losick 1997) and is relevant in natural habitats (McLean et al. 1997, Bachofen and Schenk 1998). Density-dependent phenomena, first identified in bioluminescence (Wilson and Hastings 1998), where the induced behavior is visible, have since been implicated in general foraging and defensive behaviors such as production of extracellular enzymes and antibiotics (Givskov et al. 1997, Chernin et al. 1998, Srinivasan et al. 1998). An additional development is the recognition of the tremendous importance of surface-attached bacteria in nature (Costerton 1995). Increased acquisition of nutrients has been proposed as one explanation for attachment (Ben-Ari 1999). Surfaces are also habitats for microbial consortia, or groups of bacterial species whose interdependent metabolic reactions are required for the decomposition of certain complex substrates (Wolfaardt et al. 1994, Paerl and Pinckney 1996).