| Streptomyces spp. are well known to produce antibiotics for pharmaceutical and agricultural applications. However, after years of research for novel antibiotics it is evident that isolation of additional novel compounds with biological activity has become more difficult. We have investigated a unique culture collection of 48 nitrogen-fixing Streptomyces spp. from China for the production of bioactive compounds.;To avoid replication of our screening effects, the 48 strains was evaluated using rep-PCR, a high resolution genomic fingerprinting technique. The rep-PCR analysis showed genomic diversity within the culture collection.;Preliminary bioassays indicated that one of the S. griseofuscus strains exhibited high mosquitocidal activity. Hence, it was further investigated for the chemical characterization of the compound. Bioassay-directed purification and identification of the active fraction from S. griseofuscus afforded compound 1 which gave 100% mortality of mosquito larvae (Aedes egyptii) at 20 ppm within 24 h. Also, it inhibited the growth of tobacco hornworm (Manduca sexta), cornear worn (Helicovarpa zea) and gypsy moth (Lymantria despar) at 100 ppm. |
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