• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.42-46
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• 1982

Followings are the results of growth of Pacific oysters transplanted from the temperate waters of Korea in February 1981, and cultivated upto early July in the tropical waters of Ambong Bay in Malaysia: The shell length increased from 5.78 mm in February to 25.01 mm in July, and the shell height increased from 7.33 mm in february to 38.91mm in July. The meat weight progressively increased and reached the maximum value of 1.66g in May, but then gradually decreased until July, and the fatness varied from $28\%$ of maximum in March to $11\%$ of minimum in July-Survival rate was $47\%\;and\;39\%$ of the initial number in June and July respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.121-124
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• 2002

King Oyster(Pleurotus eryngii) is one of the most promising mushrooms produced on the domestic farms. The quality as well as quantity of King oyster is sensitively affected by micro climate factors such as temperature, relative humidity, $CO_2$ concentration, and light intensity. To safely produce high-quality King oysters year round, it is required that the environmental factors be carefully controlled by well designed structures equipped with various facilities and control systems. In this study, we are focusing on carrying out growing experiment to find out reasonable range of each environmental factor together with economic and safe structures influencing on the optimal productivity of king oyster mushroom. The optimal productivity will be evaluated by considering the quality and quantity of mushroom production, energy requirements, facility construction and management cost, etc.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.210-217
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• 2018

A one-step multiplex reverse transcription PCR (RT-PCR) method comprising six primer sets (for the detection of norovirus GI and GII, hepatitis A virus, rotavirus, and astrovirus) was developed to simultaneously detect four kinds of pathogenic viruses. The size of the PCR products for norovirus GI and GII, hepatitis A virus (VP3/VP1 and P2A regions), rotavirus, and astrovirus were 330, 164, 244, 198, 629, and 449 bp, respectively. The RT-PCR with the six primer sets showed specificity for the pathogenic viruses. The detection limit of the developed multiplex RT-PCR, as evaluated using serially diluted viral RNAs, was comparable to that of one-step single RT-PCR. Moreover, this multiplex RT-PCR was evaluated using food samples such as water, oysters, lettuce, and vegetable product. These food samples were artificially spiked with the four kinds of viruses in diverse combinations, and the spiked viruses in all food samples were detected successfully.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.12a
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• pp.375-384
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• 1997

굴을 까는 작업은 굴의 껍질 에 붙어있는 근육질과 굴 껍질에 붙어있는 hinge를 절단하는 작업을 필요로 한다. 본 논문은 굴을 까는 자동화기계를 개발하기 위한 하나의 단계로서 굴의 hinge 의 위치를 판단하는 computer vision system 의 image processing software (영상처리)개발에 대하여 중점을 두었다. 본 실험에 사용한 굴들은 computer vision system이 굴의 바깥쪽 hinge 표면을 감지할 수 있도록 굴을 물로 씻은 후 굴 껍질의 hinge 부분을 약간 절단하였다. computer vision system은 color video camera를 이용하여 굴의 절단된 hinge표면의 영상을 잡은 후 image processing software를 이용하여 굴의 hinge 위치를 감지하였다. 본 논문에 사용한 computer vision software 는 일반 상용화된 software 와 굴의 hinge 위치를 알아내기 위해 저자가 연구 개발한 software 로 구성하였다. Image 내의 굴의 hinge와 그 밖의 다른 물질을 구별하기 위하여 본 논문의 software 는 4개의 변수 (circularity , Rectangularity, Aspect-ratio , Euclidian Distance)를 이용하였다. 또한 image 내의 굴의 hinge 위치를 쉽고 효과적으로 파악하기 위하여 몇 가지 영상처리, 즉, shrink-expand, thresholding 외의 다른 방법들을 이용하였다.

• Fisheries and Aquatic Sciences
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• v.6 no.2
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• pp.51-58
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• 2003

The gonadal development and the gametogenic cycle and the fine structure of ripe germ cells of the cultured Pacific oyster, Crassostrea gigas were investigated using oysters monthly collected from the southern coast of Korea from October 2000 to September 2001. Monthly changes in the condition index were similar to that of meat weight rate and the highest value was observed in between April and May, and the lowest value in August. The external colors of the testis and the ovary were milky white and yellowish, respectively. The spawning period of the Pacific oyster was continued from May to September, with a peak in July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (December to March), growing stage (March and April), mature stage (April to June), spawning stage (June to August) and resting stage (August to January). Variety of egg yolk granules, lipid granules, mitochondria, and endoplasmic reticula were observed in cytoplasm of ripe oocyte. The spermatozoon consisted of the head, middle piece and tail; including cap-shaped acrosome with domed structure, elliptical shaped nucleus, four mitochondria, two centrioles and flagellum.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.481-486
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• 2009

In 2007, 43.5% mortality of the cultured oyster population occurred in Gamak Bay. Mortality rapidly increase in September and peak in October. To prevent future mass-mortality event, we investigated spawning and variation of oyster body composition. The main spawning period of culture oyster occurred from August to September. Condition index and body composition (protein and glycogen) appeared to be influenced by the spawning activity. Condition index and glycogen content in September were lowest (13.5% and 5.6 mg/g, respectively). However, protein, lipid and glycogen contents did not rapidly recover after the spawning activity. The data indicates that mass-mortality of cultured oysters in Gamak Bay may be due to deteriorated health, spawning activity, stress of the high water temperature and decreasing food resources.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.78-83
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• 1999

Thirty-six environmental isolates of Vibrio vulnificus obtained from seawater, sediments, and raw seafoods, and 18 clinical isolates from Vibrio septicemia patients were typed by restriction endonuclease digestion profiles (REDP) of genomic DNA with SfiI. The results revealed a high-level of variation in REDPs, indicating a vast genomic diversity among V. vulnificus strains. Genetic relatedness of the strains showed similarities ranging from 10％ to 100％. Different REDPs for isolates from various raw seafoods were obtained, and clustering of strains according to type of seafoods was not observed. In contrast, clinical isolates of V. vulnificus showed higher similarity to one another, and could be subdivided into one separate group. The difference in REDPs of the V. vulnificus isolates from clinical origin and from raw seafoods substantiates the previous observation that only a single type of pathogenic strain was involved in each human infection, despite the numerous genetically polymorphic strains found from implicated oysters.

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.135-141
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• 1999

In order to investigate the composition of extractive nitrogenous components in the diploid and the triploid oysters, Crassostrea gigas, cultured at the south coast of Korea, the whole edible part (whole body) was analyzed into extractive nitrogen, free amino acids, oligopeptides, ATP and its related compounds, quaternary ammonium bases, and guanidino compounds using specimens collected from April to May of 1992. The major free amino acids in the diploid and the triploid were taurine, proline, alanine, glycine, glutamic acid hypotaurine, glutamine, arginine, aspartic acid, and $\beta-alanine$. There was no conspicuous difference in the constituents of free amino acids between the diploid and the triploid. A lot of hypotaurine was detected in the diploid and the triploid of oyster and the contents of them were 107 mg and 123 mg/100g, respectively. The compounds, glycinebetaine, homarine and trigonelline were found in both the diploid and the triploid. Among them, glycinebetaine was the most prominent in all the samples. The amount of protein, glycogen, extractive nitrogen, oligopeptides, ATP and its related compounds, and free amino acids in the triploid was higher than that of the diploid (p<0.10)

• The Korean Journal of Malacology
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• v.25 no.1
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• pp.15-22
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• 2009

Because it is known that bivalve hearts contain various modulatory systems activated by neuroendocrine substances, it was examined whether different classes of endogenous and synthetic drugs of neuroendocrinological importance can influence cardiac functions of the Pacific oyster Crassostrea gigas. Cholinergically active agents acetylcholine and carbachol increased heart rates while diminishing cardiac contractility. Adrenergically active substances norepinephrine (NE) and epinephrine (Epi) also induced heart rate increase and contractility decrease. An $\alpha_1$-adrenergic receptor-selective agonist phenyephrine (PE) failed to modulate either parameter. The Epi-induced heart rate increase and contractile depression were both blocked significantly by non-selective $\beta_1/\beta_2$-adrenergic antagonist propranolol. A $\beta_1$-selective antagonist atenolol prevented Epi-induced heart rate decrease but not the contractile depression, suggesting possible $\beta_2$ receptors for Epi-induced contractile depression. The three autacoids examined exerted discrete responses: histamine increased heart rate and depressed contraction; $\gamma$-amino-butyric acid increased both parameters; serotonin failed to change either parameter. The 5 piscine anesthetic agents examined, MS-222, benzocaine, quinaldine, urethane, pantocaine and pentobarbital, all failed to influence the cardiac function of oysters. Collectively, activities of neuroendocrinologically acting agents in mammals showed unexpected and distinct activities from those in mammalian cardiovascular systems. These results obtained from substances of different physiological functions can serve as a basis for understanding neuroendocrine control of the heart function in Pacific oyster.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.126-130
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• 2007

Noroviruses, members of the family Caliciviridae, are often found in shellfish grown in polluted water and are emerging as a leading cause of foodborne disease worldwide. As the presence of norovirus in food commodities becomes an important medical and social issue, there are increasing needs for designing improved detection methods for the virus. In this study, we tested the Agilent 2100 Bioanalyzer for the analysis of norovirus DNA amplified from oyster samples. Microchip electrophoresis provided us with more accurate information, compared to conventional agarose gel electrophoresis, in the resolution and quantification of amplified products. The development of an improved method for food-associated noroviruses would contribute to a rapid identification of contaminated food and improve our understanding of the modes of food contamination and norovirus transmission.