Danilo B. Largo, Kimio Fukami, Masao Adachi, Toshitaka Nishijima
A specific immunofluorescent probe consisting of polyclonal antibodies was developed to detect a marine bacterium. Vibrio sp. strain P11, which was found in a previous study to promote the ice-ice disease in the cultivated red macroalga, Kappaphycus alvarezii. The method involves a combined application of the fluorescent strains, 4',6-diamidino-2-phenylindole (DAPI) and the P11 PAbs, into a homogenized seaweed sample (1 g wet wt), which is prediluted to make bacteria countable under an epifluorescence microscope without serious interference from autofluorescing algal debris. The algal tissue homogenate is then filtered through a 0.2-μm-pore size Nuclepore membrane filter, serving as a mounting pad, and viewed using alternating ultraviolet and IB excitation filters to detect total and specific bacteria, respectively, on the same microscopic field, at the same time. The immunofluorescent probe could be used as a valuable tool in studying the infection mechanism of the bacterium in the macroalga in vitro.
Lab. of Aquatic Environ. Science, Department of Aquaculture, Kochi University, Nankoku City, Kochi 783-8502, Otsu 200 Monobe, Japan; Marine Biology Section, Department of Biology, University of San Carlos, Talamban Cebu City 6000, Philippines
