AME 34:11-21 (2004)  -  doi:10.3354/ame034011

ABSTRACT: Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed structural differences in bacterial communities colonizing the surface of the sponge Mycale adhaerens or an inanimate reference surface. Since these surfaces are exposed to a common pool of indigenous bacterial colonizers in the water column, the differences in bacterial community structure were attributed to differences in chemical and/or physical characteristics between sponge and reference surfaces. In order to investigate a potential chemical interaction between sponge and bacterial communities, the effect of organic extracts from both the sponge and 20 bacterial isolates from the sponge surface was tested at tissue-level concentration on 36 bacterial isolates from the reference surface. Half of these isolates were susceptible to extract from sponge tissue and 61% to those of the isolates from the sponge surface; 30% were sensitive to extracts from both sponge and isolates. In contrast, only 1 of the isolates from the sponge surface was slightly inhibited by the sponge extract (5%) and none by the extracts from the epibiotic isolates, supporting speculations on potential endo- and exogenous chemical control of bacterial epibiosis by the sponge and epibiotic bacteria, respectively.

KEY WORDS: Sponge · Mycale adhaerens · Bacterial epibiosis · Epibiotic bacteria · Benthic bacteria · Antibacterial activity · T-RFLP