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Isolation of Marine Bacteria Killing Red Tide Microalgae I. Isolation and Algicidal Properties of Micrococcus sp. LG-1 Possessing Killing Activity for Harmful Dinoflagellate, Cochlodinium polykrikoides (적조생물 살조세균 탐색 I. 유해 적조생물 Cochlodinium Polykrikoides 살조세균 Micrococcus sp. LG-1의 분리와 살조특성)

  • PARK Young-Tae;PARK Ji-Bin;CHUNG Seong-Youn;Song Byung-Chul;LIM Wol-Ae;KIM Chang-Hoon;LEE Won-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.5
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    • pp.767-773
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    • 1998

  • In this study, we have investigated the distributions and killing effects of marine bacteria that tend to kill the red tide microalgae, C. polykikoides in the area of Masan bay from June to October, 1996. To summarize, C. polykikoides killing bacteria were detected at $10^2$ to $10^3$ cells/ml of seawater samples during the survey period, and the bloom was observed in September by containing $4.8\times10^3$cells/ml. It appears however that the number of these bacteria is decreased ($2.0\times10^2$cells/ml) in October, A total of 110 strains were isolated from seawater samples and seawater filtrate (pore size, 0.8 $\mu$m)-containing mixed culture of C. polykikoides in which the mixed culture was grown in f/2 medium. As results we have successfully isolated Micrococcus sp. LG-1 which decreased to less than 10cells/ml within 6days and 5days sfter inoculation of Micrococcus sp. LG-1 into the la9 and logarithmic growth phases of C. polykrikoides respectively. Therefore, it appears that inoculation of Micrococcus sp. LG-1 against the logarithmic C. polykrikoides is more effective than the lag growth phase, (n addition, the killing effects were increased in accordance with bacterial cell densities inoculated in a dose dependent manner. Especially, the filtrate of kitling bacterium culture (nore size, 0.2 $\mu$m) revealed a dramatic effect in which C. polykrikoides were decreased to less than 10 cells/mf of culture within 1 hr, 1,5 hrs, 1,5 hrs, 3.5 hrs. and 5,5 hrs after inoculations of the culture filtrate with concentration of $30\%,\;20\%,\;10\%,\;5\%$ and $2.5\%$, respectively. Moreover Micrococcus sp. LG-1 showed a selective specificity against C. polykrikoides and any other killing effects of Micrococcus sp. LG-1 were not observed against Alexandrium tamarense, Prorocentrum micans, Scrippsiella trochoidea. ana Gymnodinium sanguineum.

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Early Changes after Death of Plaice, Paralichthys olivaceus Muscle -4. Effect of Killing Methods on Rigor Index and Breaking Strength of Muscle- (넙치(Paralichthys olivaceus)육의 사후 조기 변화 -4. 치사 방법이 육의 사후 경직도와 파괴 강도에 미치는 영향-)

  • CHO Young-Je;LEE Nam-Geoul;KIM Yuck-Yong;KIM Jae-Hyun;CHOI Young-Joon;KIM Geon-Bae;LEE Keun-Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.27 no.1
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    • pp.41-46
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    • 1994

  • This study was undertaken to clarify the effect of killing methods on physical and rheological changes of plaice, Paralichthys olivaceus muscle at early period after death. Plaices killed by the four different methods(1. spiking at the brain instantly. 2. drowning in air. 3. dipping in 1,000ppm ethylaminobenzoate dissolved sea water as an anesthetic. 4. electrifying in sea water.) were stored at $5^{\circ}C$, and the rigor-index and breaking strength through storage were monitored. The longest onset time of rigor-mortis and full rigor was in the samples killed by dipping in sea water with dissolved anesthetic among all samples, where rigor-mortis began at 20hrs after killing and maximum tension was attained after 56hrs. However, in the cases of plaice electrified in sea water or drowned in air, the onset of rigor-mortis began just after killing and maximum tensions were attained after 9hrs and 13hrs, respectively. The level of breaking strength in the muscle of fish killed by spiking the brain instantly was $950.30{\pm}50.23g$, immediately after killing. The value and time reached around the maximum breaking strength for each of the samples were $1,230.60{\pm}30.32g$ and Ohr (immediately after killing) for samples killed by electrifying in sea water, $1,235.83{\pm}35.37g$ and 2.5hrs for drowning samples, $1,186.29{\pm}55.90g$ and 10hrs for spiking samples, and $1,189.67{\pm}50.32g$ and 15hrs for samples dipped in anesthetic, respectively. From the results above, it could be concluded that electrification in sea water is the most effective method in accelerating rigor-mortis and shortening times of reaching the maximum breaking strength of fresh plaice flesh of all the killing methods at early periods after death, whereas dipping in sea water treated with anesthetic was the most effective way in delaying those changes.

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