ENRICHMENT AND PURIFICATION OF CHAOBORUS KAIROMONE FROM WATER - FURTHER STEPS TOWARD ITS CHEMICAL CHARACTERIZATION

Predatory larvae of the genus Chaoborus release a chemical compound (k airomone) into the water which induces morphological changes, as antip redatory defenses, in daphnids. We present a method for enriching the active compounds released by the larvae directly from their aquatic en vironment by sorbent extraction. We developed a fast microscale bio-te st based on Daphnia pulex morphological response to the kairomone to o btain new information about the kairomone's chemical nature. Carboxyl and hydroxyl groups are essential for kairomone activity. The kairomon e can be characterized as a low-molecular weight, non-olefinic hydroxy -carboxylic acid. Separation by reversed-phase HPLC yields only one ac tive fraction. The kairomone can be purified by anion exchange and HPL C. This is the first time a kairomone, which is sensed by Daphnia, has been enriched from water by sorbent extraction technology. This techn ique of enrichment offers the possibility of following seasonal kairom one concentrations in natural environments.