碩士 / 國立海洋大學 / 食品科學系 / 87 / ABSTRACT
Gill, intestinal walls and skin samples of Torafugu (Takifugu rubripes) collected from Jiaohsi and Toucheng, Ilan County and Sandiaujau, Taipei County, were plated on PPBE (Proteose peptone beef extract) agar and ORI (Ocean Research Institute) agar both for aerobic plate count. Numbers of anaerobic plate count were determined by TPGY (Trypticase peptone glucose yeast extract ) agar. Pond water and sediment were determined for both aerobic and anaerobic plate counts by the same methods used for fish samples. A total of 345 strains were isolated and characterized morphologically, physiologically and biochemically for taxonomic classification to species or genus . Bacterial counts of gill were highest in summer with 5.2×106, 4.4×106 and 4.4×106 CFU/g plated on PPBE, ORI and TPGY agar, respectively. The bacterial load was found highest in intestinal walls among three part samples of the fish and the highest counts were found in Spring with 6.4×108, 8.5×108 and 1.5×109 CFU/g plated on PPBE, ORI and TPGY media, respectively. In fish skin, 1.6-2.3×106 CFU/g were found highest in Jiaohsi during the Summer. Aerobic counts with 7.0×103-2.0×105 CFU/ml were found in pond water and 1.1×106-1.4×107 CFU/g in sediment in Jiaohsi. Similar result of 3.5×104-2.7×105 CFU/ml was found in pond water in Toucheng.
In Summer, Vibrio alginolyticus was found to be the commonly predominant genus in all samples tested in both Toucheng and Sandiaujau aquacultural facilities. Vibrio alginolyticus and Acinetobacter, and Vibrio alginolyticus were found to be the predominant organisms in three samples collected from Jiaohsi, Ilan County when plated on PPBE and ORI media, respectively. Similarly, V. alginolyticus was also found to be the predominant organism in Toucheng ponds. In Spring, the predominant organisms found in PPBE were similar to that tested in Winter. Nevertheless, V. alginolyticus was the predominant species and other organisms such as Pseudomonas, Acinetobacter, Moraxella and other Vibrio sp. also found in gill and fish skins when plated on ORI medium for samples of Toucheng ponds. In pond water and sediment, Vibrio, Pseudomonas, Serratia and Micrococcus were the commonly found organisms when cultured on PPBE while Vibrio, Pseudomonas and Acinetobacter were prevalent on ORI medium in samples taken from Jiaohsi, Ilan. V. alginolyticus, Pseudomonas, Acinetobacter, V. parahaemolyticus and Serratia were the common organisms detected in PPBE and ORI found in sediment taken from Jiaohsi. Whereas, Pseudomonas and Moraxella were the common organisms in pound water found in both of these two agar plates. The predominant organisms appeared in pond water of Toucheng were Vibrio and Pseudomonas .
In order to understand if bacteria can produce Tetrodotoxin (TTX) four isolates were selected for determination of toxin production. The culture grown for 3 days in 1L BHI (Brain heart infusion) or ORI medium were harvested, freeze-dried and prepared for TTX determination. After 0.1% acetic acid extraction, the suspension was separated into cell extract, cell residue and medium filtrate. All three fractions were freeze-dried and suspended in 0.1% acetic acid. The TTX analyses were performed by high performance liquid chromatography. V. alginolyticus O1SS01 was found to have a higher likely TTX producting ability with a clear peak, identical to the authentic TTX sample, found in the cell extract and cell residue as identified by HPLC. Three peaks of anh-TTX, TTX and 4-epi TTX fractions in descending order were clearly shown on HPLC analysis. Cell extract from V. alginolyticus O1SS01 cultured on ORI medium also contained slightly TTX likely compound. Other 3 strains, Vibrio O4TG01, Pasteurella P4JI04 and V. alginolytion P3JS02 were also able to produce anh-TTX only and none were able to produce TTX.
| Identifer | oai:union.ndltd.org:TW/087NTOU0253030 |
| Date | January 1999 |
| Creators | Mai Liem Huang, 黃美連 |
| Contributors | T. J. Chai, D. F. Hwang, 蔡土及, 黃登福 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 127 |
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