Occurrence of Marine Saprospira sp. Possessing Algicidal Activity for Diatoms

Unicellular algae are autotrophic eukaryotes which contribute to overall primary production in any aquatic ecosystems.Furthermore, some of them are very usefull in the aquaculture of fish, shrimp and shellfish as primary live food.However, the pathogens for the unicellular algae are not well known.Although various algal lysing agents have been reported for freshwater blue-green algae, few papers described algicidal microbes for eukaryotic algae in fresh and marine environments.1, 2)In this paper, the author observed non-fruiting gliding bacterium that attacks the cells of a diatom, Chaetoceros calcitrans (simplex) cultured in Kagoshima Prefecture, Japan as live food for juveniles of a large winged pearl shell, Pteria penguin.