Abstract
Marine microbial resources have been considered as potent sources for new and potent medicines. We have constructed marine microbial library consists of 50,000 strains. Among them, 26,000 strains have phylogenetically analyzed based on SSU–rRNA sequences. Number of biologically active substances have been isolated from marine microbes in this library using the screening based on marine phenomena. One typical example is thallusin (2), isolated in 2005 after pursuing for more than 50 years, showed foliaceous morphology–inducing activity at the exceptionally low concentration. Antimicroalgal substances HML (6) and Kailuin B (9) have been isolated from marine bacteria belongs to Vibrio. These compounds showed selective toxicity only against dinofragellates. Useful microalgae such as diatom was unaffected by these substances. Interestingly, these substances also showed potent anti–malarial activity. It is not strange, because dinofragellete and malaria are phylogenetically related to each other. As shown in the isolation of above mentioned substances and unnermicins, the screening methods based on marine phenomena seemed to be useful for the efficient isolation of novel biologically active compounds.
