The correlation between the allocation of trisoxazole macrolides in the capitums, appendages, and bases of the sponge Penares cf. nux and the surface-attached bacteria on the corresponding parts was examined. The kabiramide contents were highest in the capitums, followed by the appendages and bases. Conversely, direct counts of cultivable surface-attached bacteria showed that the bacteria aggregate more densely on the surfaces of the bases. This suggested the repelling effects of the kabiramides against the fouling bacteria, particularly on the capitums and appendages. Twenty-two bacterial strains were isolated and identified to 15 species; however, none has shown the potentials as a producer of any secondary metabolites in the sponge P. nux.
Keywords: Penares nux; kabiramides; sponge-associated bacteria; trisoxazole macrolides.