Differentiation of chitinase-active and non-chitinase-active subpopulations of a marine bacterium during chitin degradation

The ability of marine bacteria to adhere to detrital particulate organic ma tter and rapidly switch on metabolic genes in an effort to reproduce is an important response for bacterial survival in the pelagic marine environment , The goal of this investigation was to evaluate the relationship between c hitinolytic gene expression and extracellular chitinase activity in individ ual cells of the marine bacterium Pseudoalteromonas sp, strain S91 attached to solid chitin, it green fluorescent protein reporter gene under the cont rol of the chiA promoter was used to evaluate chiA gene expression, and a p recipitating enzyme-linked fluorescent probe, ELF-97-N-acetyl-beta-D-glucos aminide, was used to evaluate extracellular chitinase activity among cells in the bacterial population, Evaluation of chiA expression and ELF-97 cryst al location at the single-cell level revealed two physiologically distinct subpopulations of S91 on the chitin surface: one that was chitinase active and remained associated with the surface and another that was non-chitinase active and released daughter cells into the bulk aqueous phase. It is hypo thesized that the surface-associated, non-chitinase-active population is ut ilizing chitin degradation products that were released by the adjacent chit inase-active population for cell replication and dissemination into the bul k aqueous phase.