碩士 / 國立成功大學 / 生物科技研究所碩博士班 / 100 / In the laboratory previously research, we have found that applied a marine microalga Picochlorum sp. S1b in tanks of grouper (Epinephelus coioides) larvae which significantly reduce the number of vibrio density in the water. We speculated that S1b produce vibrio static ingredients, compete-specific nutrition or some bacteria symbiosis with S1b inhibit vibrio growth. We selected two species of vibrio, Vibrio harveyi strain BCRC12907 and V. campbellii strain BCRC12909 and evaluated the vibrio static activity of S1b crude extract (45 mg/mL), according to the inhibition zone formed on agar plates through well diffusion method. Then spiked vibrio (3.35 x 103 CFU/mL) into the axenic and non-axenic (opened culture) S1b, measurement the viability of vibrio, to understand whether the vibrio static activity from its symbiotic bacteria.
Results show that the S1b crude extract does not have significant inhibitory activity, then the vibrio viability in axenic and non-axenic S1b were significant differences for co-culture 48 hours, the former vibrio density increased to 1.47 x106 CFU/mL, 500 times of initial inoculum; however, the vibrio density of the latter, remained non-detectable (〈 15 CFU/mL). Thus the S1b inhibit the vibrio through its symbiotic bacteria, rather than microalga itself.
In order to further study the non-axenic S1b containing bacteria which can inhibit the vibrio, we isolated bacteria randomly from the non-axenic medium spread marine agar plate, followed by well diffusion method, analysis which strain has the ability to inhibit vibrio, as well as cloning the 16S rDNA sequence and alignment with database to identify the strain. As a result, a total 80 strains, respectively, 14 and 11 can inhibit the V. harveyi BCRC12907 and V. campbellii BCRC12909 growth (inhibition zone 〉 2.0mm), while 3 bacteria can inhibit both two species of vibrio. Further co-cultured with the axenic S1b, and spike the vibrio, confirm which strain process vibrio static activity. We found that indeed some strains of isolate reduce the density of vibrio (strains 7,8,46,48,50 and 61). Through the 16S rDNA alignment, the bacteria process vibrio static activity is roughly Rhodobacteraceae, Flavobacteriaceae, further we will search for related research and speculated the proper vibrio static activity mechanism of these lsolated.
| Identifer | oai:union.ndltd.org:TW/100NCKU5111119 |
| Date | January 2012 |
| Creators | Jung-CheKuo, 郭榮哲 |
| Contributors | Yi-Min Chen, 陳逸民 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 89 |
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