| Summary: | 碩士 === 國立陽明大學 === 生物化學研究所 === 87 === Fungicides are often used to control fungal diseases for plant protection in agriculture. Because of the increasing arise of drug resistant fungi and most of the fungicides are not biodegradable that causes residual toxicity to other organism. The development of new antifungal agents that possess low toxicity, high efficacy, and high selectivity is necessary. In this study, methods for the isolation of bacterial strains from animal feces is evaluated.
From a collection of 10 different animal feces, a total of 459 Actonimycetes strains were isolated. We found that pretreatment of animal feces with SDS-yeast extract and use of M3, A1, or HV media gave better recovery of Actinomycetes strains. In addition, using phytopathogenic fungi Pythium splendens, Rhizocotonia solani, and Phytophthora capsici as the tested strains for antifungal agent-screening model, the antifungal activity of 48 laboratory antifungal strains were analyzed. These 48 strains were previously collected for their inhibitory activity in Candida albican growth. The culture medium prepared from strain 84A22, a Streptomyces alboviridis, inhibited the growth of both P. splendens and P. capsici. The active component existing in the culture medium of 84A22 was purified by ethyl acetate extraction, silica gel column chromatography, and HPLC. Mass spectrometric analysis indicated that the molecular weight of this active component is ~1100. Determination of the structure of this active component is currently in progress.
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