| Abstract: | This report describes a simplified method for direct counting of total bacteria associated with the fleshy red algae Kappaphycus alvarezii (Doty) Doty and Gracilaria spp. A Nuclepore® polycarbonate membrane (0.2–μm pore size) fitted to a vacuum filtration apparatus was used to filter algal tissue homogenate after serial dilution and staining with the fluorochrome 4′,6-diamidino-2-phenylindole. Using epifluorescence microscopy, it is possible to count bacteria without preseparating them from the algae. The technique requires homogenized algal tissue diluted with 0.2-μm-filtered, autoclaved seawater to a level appropriate for counting. Dilution reduces the amount of autofluorescent algal debris, which may interfere with Counting. The membrane filtration method yielded a bacterial count two orders of magnitude higher than that of the conventional agarspread plate technique. This method offers a more accurate approach to counting the total number of bacteria on macroalgae. |
