|Nanayakkara, Dhammika N.|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2003
Publication Date: 9/1/2003
Citation: SCHRADER, K., NANAYAKKARA, D.P., TUCKER, C.S., RIMANDO, A.M., GANZERA, M., SCHANEBERG, B.T. NOVEL DERIVATIVES OF 9,10-ANTHRAQUINONE ARE SELECTIVE ALGICIDES AGAINST THE MUSTY-ODOR CYANOBACTERIUM OSCILLATORIA PERORNATA. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 2003. V.69(9). P.5319-5327. Interpretive Summary: New compounds derived from the natural compound anthraquinone, found in some plants, were made and tested to determine if they are useful as selective algicides in catfish aquaculture ponds. In laboratory tests, anthraquinone was previously found to be effective in reducing the abundance of the blue-green alga that produces musty off-flavor in farm-raised channel catfish. However, anthraquinone is not water-soluble and did not reduce the abundance of the musty blue-green alga in catfish pond studies. The new derivatives of anthraquinone are water-soluble and were effective in reducing the abundance of the musty odor compound and the musty blue-green alga in water in catfish pond studies.
Technical Abstract: Musty "off-flavor" in pond-cultured channel catfish (Ictalurus punctatus) costs the catfish production industry in the United States at least $30 million annually. The cyanobacterium Oscillatoria perornata (Skuja) is attributed with being the major cause of musty off-flavor in farm-raised catfish in Mississippi. The herbicides diuron and copper sulfate, currently used by catfish producers as algicides to help mitigate musty off-flavor problems, have several drawbacks including broad-spectrum toxicity towards the entire phytoplankton community that can lead to water quality deterioration and subsequent fish death. Using microtiter plate bioassays, a novel group of compounds derived from the natural compound 9,10-anthraquinone have been found to be much more selectively toxic towards O. perornata than diuron and copper sulfate. In efficacy studies using limnocorrals placed in catfish production ponds, application rates of 0.3 uM (125 ug/L) of the most promising anthraquinone derivative, 2-[methylamino-N-(1´-methylethyl)]-9,10-anthraquinone monophosphate (anthraquinone-59), dramatically reduced the abundance of O. perornata and levels of 2-methylisoborneol, the musty compound produced by O. perornata. The abundance of green algae and diatoms increased dramatically 2 days after application of 0.3 uM of anthraquinone-59 to pond water within the limnocorrals. The half-life of anthraquinone-59 in pond water was determined to be 19 h, making it much less persistent than diuron. Anthraquinone-59 appears to be promising for use as a selective algicide in catfish aquaculture.