| Summary: | 碩士 === 國立臺北科技大學 === 化學工程與生物科技系生化與生醫工程碩士班 === 107 === The proportion of fungal infection among microbe infection has increased annually. However, the overuse of few available antifungal-drugs causing multiple drugs resistant and makes great difficulty for complete cure. The reasons for slow development of new antifungal drugs is mainly because the fungi belongs to eukaryotic organisms. Their cell structure and metabolism pathways are similar to humans or animals and plants, which reduce drug specifically act on fungi. Also, most of the current antifungal drugs are exhibited hepatotoxicity and/or nephrotoxicity. Negative co-effect also been observed when co-treatment with different antifungal drugs were applied, resulted in unexpected efficacy. This study targeted on screening new antifungal substances from soil bacteria, a strain of Streptomyces (previously named SC26) was screened in our laboratory with a very good inhibitory effects on various fungi, such as C. albicans, A. niger, Rhodotorula spp, A. pullulans, P. guilliermondii, V. dahlia and P. nodorum. No identical strain was found after comparing it’s 16S rRNA within NCBI gene pool, suggesting SC26 might be a novel strain. SC26 can secrete antifungal substances (AFF) under liquid culture condition. Physical properties analysis of AFF had shown: its stable between pH 3 to pH 10, molecular weight is more than 100 kDa, high temperature sensitivity, resistance to pepsin, trypsin but sensitive to Bacillus subtilis proteases, high hydrophilicity so could not be extracted by organic solvents and carry negatively charged under alkaline condition. No toxicity to fibroblasts was found during cytotoxicity test.
Concluding above results, it is reasonably presumed that AFF can be a protein.
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