PRODUCTION OF AN ALGICIDE FROM CYANOBACTERIUM FISCHERELLA SPECIES WHICH INHIBITS PHOTOSYNTHETIC ELECTRON-TRANSPORT

Incubation of the filaments, culture filtrate and cell-free extract of Fischerella sp. (axenic isolate) inhibited growth of some cyanobacter ia and a green alga. An algicidal metabolite from the cell-free extrac t, which abolished the photosystem (PS) II activity in spinach chlorop lasts and cyanobacteria, was extracted in ether. Chlorophyll fluoresce nce and electron transport data indicated that the algicide interacted at the acceptor site of PS II. Upon thin layer chromatography of the ether extract, a fraction with algicidal activity fluoresced under ult raviolet light and contained long-chain saturated fatty acids.