碩士 / 國立中山大學 / 海洋資源學系 / 85 / Aeromonas hydrophila and Edwardsiella tarda are the major pathogen of eels. At present, antibiotics are widely used in culture ponds in order to kill pathogenic bacteria, but the chemotherapeutic method is not successful for controlling the drug-resistant strains. It''s necessary to find another way for killing pathogenic bacteria. In the nature, bacteriophages are an important factor of bacterial mortality. The purpose of this studies was to understand the ability of bacteriophages lysis of bacterium in the natural water. In this study, five bacteriophages were isolated from southern Taiwan aquatic environment. The bacteriophages isolated on A. hydrophila ATCC 7966, E.tarda CCRC 10670 and the E.tarda strain from diseased eel were named as A1, A2, E1, E2 and ψE1. After characterization, bacteriophages A2, E1 and E2 contained double-stranded DNA. The bacteriophage genomes could be cut with restriction endonuclease EcoR I into at least 6, 20 and 22 fragments. Those five bacteriophages could lyse their hosts quickly. The total viable cells could be reduced to less than １０-3－１０-5 of starting concentration by infection at an M.O.I.=10 in 2 hours. In selective media evaluation, starch-ampicillin agar permitted quantitative recovery and showed good accuracy of A. hydrophila for counting from natural water, the salmonella-shigella agar can also be using for counting E. tarda. In field experiment, the viable A. hydrophila concentration was reduced to 0.004 of original concentration ６ ×１０5/ml after adding bacteriophage A1 to M.O.I.=0.234 within 8 hours and relased large quantity bacteriophages. However, E.tarda could not be matained in nature water. Without adding bacteriophage, the viable E.tarda concentration was reduced to 0.001 of original concentration １０4/ml in nature water during 48 hours.
| Identifer | oai:union.ndltd.org:TW/085NSYS3277008 |
| Date | January 1997 |
| Creators | 羅仲邑 |
| Contributors | 徐基新 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 85 |
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