Antibacterial activity of two species of bryozoans from northern Puget Sound
Shellenberger, Jill S.
Ross, JuneR. P.
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For the first time, bryozoan species from northern Puget Sound have been shown to contain antibacterial compounds. The antibacterial activity of two local marine cheilostome species was tested against six strains of local marine bacteria and against stock cultures of Vibrio anguillarium, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The filter paper disc method was used to test for antibacterial activity. A crude extract made from the bryozoan Bugula pacifica inhibited the growth of two marine isolates, as well as B. subtilis, S. aureus, and E. coli. A crude extract made from the bryozoan Tricellaria occidentalis inhibited the growth of B. subtilis. Preliminary scanning electron microscopy data indicate that Tricellaria occidentalis had higher densities of surface bacteria than Bugula pacifica. This inverse relationship between antibacterial activity and surface fouling may indicate an antifouling role for these bryozoan secondary metabolites. The presence of antibacterial compounds may allow bryozoans to manipulate the microbial film growing on them, and may influence the types of organisms that are able to settle near or on them. The ability to manipulate microbial films may also enable bryozoans to make the substrate nearby more suitable for the settlement of their own larvae