碩士 / 國立中山大學 / 海洋生物科技暨資源學系研究所 / 103 / Acinetobacter baumannii is an opportunistic pathogen, which easily develop a drug-resistant strain and is liable to spread and increase the mortality in the hospital.Therefore, to develop new antibiotics to treat the patients with infection by A. baumannii became an important research object. On the other hand, marine microorganisms develop a series of specific organic-ligand systems to assist them harvest iron, zinc, and other trace metals to survive in the trace metals-insufficient seawater environments. These organic ligands are species-specific to influence the growth of other microorganisms by scavenging environmental trace metals. Such ligands can be also regarded as anti-microbial components to treat patients infected with pathogens.
To search novel anti-microbial secondary metabolites from marine microorganisms, we found that two marine fungi, Trichoderma reesi (MR13-TR01) and T. atroviride (MR13-TA01), isolated from a sponge Niphates collected from Wan-Li Tong, Pingtung County, showed clearly good inhibitory effects against eight bacterial indicators and one fungal indicator, especially for A. baumannii. Both also showed the iron-chelating effect by the Chrome azurol S (CAS) assay. Through the bioactivity-guided fractionation isolation (BGFI), we isolated four new peptaibols, as well as 16 known compounds, including four peptaibols, five polyketides, two known diketopiperazines, two sesquiterpenes, one alitol, one nucleoside, and one disaccharide, from the extracts of the two marine fungi. The structures of the compounds mentioned above were elucidated by spectroscopic (UV, IR, CD, NMR, HRESI-MS) and chemical methods. In addition, eight peptaibols showed inhibitory effect against A. baumannii, especially for compound 1. And some of them also had the clear iron-chelating effect by the CAS assay. In addition to the compound 5 had a great activity for the oral cancer cell CAL 27, and the IC50 = 13.0 ug/mL。
| Identifer | oai:union.ndltd.org:TW/103NSYS5277026 |
| Date | January 2015 |
| Creators | Yi-yu Chen, 陳儀諭 |
| Contributors | Chih-Chuang Liaw, 廖志中 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 240 |
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