Investigating the spatial distribution of Actinomycete bacteria in the Indonesian Sponge, Aaptos aaptos

The Indonesian Sponge, Aaptos Aaptos, was analyzed in order to assess the spatial distribution of the bacterial community present within the sponge with a particular focus on Actinomycetes. Three A. aaptos sponge individuals were chosen and three regions of each individual were sampled: Pinacoderm, Outer Mesohyl, and Inner Mesohyl. Using conventional microbiological techniques, bacteria present in the sponge tissue from each region were cultured on three media types: Marine Agar, R2A 2%NaCl and ISP2 2%NACl (selective media for isolation of Actinomycetes). From the assemblage of bacteria that were cultured, novel isolates were selected for preparation of organic extracts. These isolates were transferred to liquid media, grown until dense cultures were obtained and extracted using 1-butanol as a solvent. Extracts were analyzed in order to obtain a chemical profile of the compounds being produced by the isolates. Recognizing that recovery from culturing techniques is limited, molecular techniques were also applied to total bacterial community DNA extracted from the sponge tissue. Universal bacterial primers were used to amplify regions of the bacterial 16S rRNA genes from the DNA extracted from the three regions of the sponge. Amplicons were resolved by denaturing gradient gel electrophoresis (DGGE). A genetic fingerprint was obtained, confirming that the bacterial community was highly conserved throughout the three regions. Results from the microbiological and molecular techniques were compared in order to detect subtle differences in the bacterial communities from the three regions.