• Korean Journal of Microbiology
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• v.49 no.2
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• pp.156-164
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• 2013

Actinomycetes produce diverse secondary metabolites which have the primary importance in medicine, agriculture and food production, and key to this is their ability to interact with other organisms in natural habitats. In this study, we have investigated the taxonomical and functional diversity of actinomycetes in fecal sample of rhinoceros beetle larvae (Allomyrina dichotoma L.) by using culture-dependent and -independent approaches. For the culture-independent approach, the community DNA was extracted from the sample and 16S rRNA genes of actinomycetes were amplified using actinomycetes-specific PCR primers. Thirty-seven clones were classified into 15 genera and 24 species of actinomycetes. For the culture-dependent approach, 53 strains were isolated from larval feces, of which 27 isolates were selected based on morphological characteristics. The isolates were classified into 4 genera and 14 species, and 24 isolates (89%) were identified as the genus Streptomyces. Many of the representative isolates had antimicrobial activities against plant pathogenic fungi and Gram-positive bacteria. In addition, most of the isolates (78%) showed biochemical properties to hydrolyze cellulose and casein. The results demonstrated that diverse and valuable actinomycetes could be isolated from insect fecal samples, indicating that insect guts can be rich sources for novel bioactive compounds.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.90-95
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• 1999

For the control of the greenhouse whitefly, Trialeurodes vaporariorum entomopathogenic fungi were isolated from forest soils and infected insects. We selected three strains, which showed high pathogenicity and named as SFB-582(Beauveria sp.), SFP-198(Paecilomyces fumosoroseus) and SFV-1053(Verticillium sp.) respectively. Particularly, at the concentration of $10^{7}$ conidia/ml, P. fumosoroseus SFP-198 had the highest pathogenicity, $91.4{\pm}3.5%$ in laboratory. In glasshouse application, $91.4{\pm}3.5%$ SFP-198 showed high protective values($80{\sim}90%$) regardless of developmental stages, which were similar with that of Verticillium lecanii F-903 already reported. Four kinds of formulations of entomopathogenic fungi were developed, formulation with surfactant Silwet L-77 gave best control of greenhouse whitefly(over 90%). These results suggest that P. fumosoroseus SFP-198 is a promising candidate as a microbial pesticide for the control of T. vaporariorum.