• Title/Summary/Keyword: Oysters

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Microplastics in the Marine Environment and Their Impacts on Human Health (해양 환경의 미세 플라스틱과 인간의 건강에 미치는 영향)

  • Bak, Jia;Kang, Hyun Bon;Choi, Yun-Sik
    • Journal of Life Science
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    • v.31 no.4
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    • pp.442-451
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    • 2021
  • Microplastics are fragments of any type of plastic with a size less than 5 mm. Ocean pollution by microplastics is now a worldwide concern in relation to marine ecosystems and human health. The widespread contamination by microplastics means that they can be ingested by and accumulated in diverse species of wildlife, such as fish, mussels, oysters, clams, and scallops. Once ingested, the microplastics can be observed in the intestines, liver, and kidney, and even in the brain. Seafood is one of the major sources of protein intake in humans; therefore, seafood consumption could be pathway for human microplastics exposure. Accumulating evidence indicates that repeated oral exposure to microplastics induces pathologic and functional changes in the reproductive, cardiac, gastrointestinal, endocrine, and even nervous systems of rodents. Maternal exposure to microplastics during gestation and lactation alters metabolic homeostasis in the offspring. Given that seafood provides more than 20% of the total protein intake by over 310 million people worldwide, a reasonable assumption is that microplastics could be substantially accumulated in the human body and impair physiological function. In this review, we have summarized the current status of microplastics contamination in the ocean, their accumulation and toxicities in marine animals and rodents, their exposure to humans, and their potential impacts on human health.

Site Suitability Assessment Using the Habitat Suitability Index for Oyster (Crassostrea gigas) in Jaran Bay, Korea (서식지 적합 지수를 이용한 자란만 굴(Crassostrea gigas)의 어장적지평가)

  • Yong-Hyeon Choi;Sok Jin Hong;Dae In Lee;Won Chan Lee;Seung Ryul Zeon;Yoon-Sik Cho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.5
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    • pp.427-434
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    • 2023
  • Oysters are an important organism, accounting for an average of 76% of shellfish aquaculture production. In this study, optimal habitat was searched for by calculating the Habitat Suitability Index (HSI) using water temperature, salinity, hydrodynamics, DO, SS and Chl.a in Jaran Bay. As a result, the inside of Jaran Bay was found to be a more suitable habitat than the outside with a wide entrance and rapid hydrodynamics. Oyster production and HSI showed a significant correlation (0.710, p<0.05). Hydrodynamics helps the growth of aquaculture organisms, such as food supply through seawater exchange in the bay, which showed a high correlation (0.709, p<0.05) with oyster production. It was found to have a greater effect on habitat suitability than Chl.a. The results of this study are expected to be helpful for the efficient conservation, use and management of coastal fisheries.

Analysis of production performance and sensory evaluation for shucking oyster using pressure (압력으로 박신한 굴 생산성능과 관능평가 분석)

  • Ok-sam KIM;Eun-Bi MIN;Doo-jin HWANG;Geum-Bum YOO
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.59 no.1
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    • pp.35-43
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    • 2023
  • Sensory evaluation of shucking pressure, pressure holding time, seeding method, difference in full shucking rate in the aquaculture area and shucking oyster was performed using an ultra-high pressure oyster shucking machine. The reaching time for each target pressure is 2.2-2.4 MPa/sec in the range of 180 MPa to 240 MPa. had a rate of pressure rise. There was a difference of 0.5-1.7℃ in the range of 24-27℃ in the seawater temperature before and after the pressure treatment inside the pressure vessel, but there was no specific increase or decrease in seawater temperature. When only the shucking pressure is increased without the pressure holding time, the critical shucking pressure at which the oyster shell is opened and the flesh is peeled in the range of 200 to 220 MPa. When the critical shucking pressure is reached, the oyster sample in the closed vessel is expected to be shucked by about 40%. If there is no pressure holding time when judged only by full shucking, an increase in pressure of about 1.5 MPa is required to further shuck 3% of the oyster population. The oyster samples cultivated in the south coast of Korea were subject to full shucking under the conditions of 220 MPa shucking pressure and two minutes (120 seconds) of pressure holding time, and the difference in the pressure of the oysters according to the oyster seeding method and the farming area was minute. Finally, the condition of 220 MPa of shucking pressure and three minutes of pressure holding time was the best at 1.52 when the result of the sensory evaluation performed manually was set to 1.0. Next was 1.4 under the conditions of 220 MPa of shucking pressure and one minute of pressure holding time (60 seconds), and 1.3 under the condition of 220 MPa and two minutes of pressure holding time (120 seconds). Therefore, it is considered that the most desirable shucking conditions, considering the efficiency and sensory evaluation results, are the conditions of 220 MPa shucking pressure and two to three minutes of pressure holding time.

Studies on Kimchi for its Standardization for the Industrial Production Part 1. Survey of Status Industrial Production (김치의 공업적(工業的) 생산(生産)을 위한 공업표준화(工業標準化)에 관(關)한 연구(硏究) 제(第)1보(報) 공업적생산(工業的生産)을 위한 조사(調査))

  • Yu, Tai-Jong;Chung, Dong-Hyo
    • Korean Journal of Food Science and Technology
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    • v.6 no.2
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    • pp.116-123
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    • 1974
  • 1) In Seoul, it was known that the season for preparing Kimchies (fermented vegetables) for the winter was from the middle of November to early in December, in which the preparing rates of Kimchies in the middle of November, the end of November and early in December were 32.7%, 41.3% and 12.5%, respectively. The time that the largest quantity of them was prepared was about the end of November. 2) The average cost of Kimchies prepared for the winter for a family of four, five, six and seven was $10,000{\sim}15,000$ Won, $15,100{\sim}20,000$ Won, $10,100{\sim}20,000$ Won and $10,100{\sim}20,000$ Won, respectively, and the cost did not increase in proportion to members of a family. In case of the family of $6{\sim}7$, the cost for Kimchies showed a wide range compared with those for the family of $4{\sim}5$ 3) The main raw materials of kimchi for one person for the winter required $12{\sim}20$ heads of Chinese cabbages, $14{\sim}20$ roots of radishes, $4{\sim}7$ cloves of garlics and $300{\sim}500g$ of powdered red pepper. 4) The residents living in Seoul had prepared the several kinds of the pickles for the winter as follows; (1) Chinese cabbage Kimchi (98.9%), (2) Whole Chinese cabbage Kimchi (74.7%), (3) Kkakdugi (68.6%), (4) Dongchimi (66.4%) and (5) Chong-kak Kimchi (63.3%). It has, therefore. been considered that the five kinds of Kimchies mentioned above may be industrialized. 5) Uniqueness of the raw materials used for the most popular Chinese cabbage Kimchi was to use leeks, garlics, red peppers and gingers as spices, and it was also known that proper amounts of salted shrimp pickles and oysters was mixed to the Kimchies. Therefore, it had been considered that the characteristics of Chinese cabbage Kimchies for the winter had the hot taste with freshness. 6) For keeping the Kimchies during the winter about the half of the pickle jars was buried in the ground, and another half of them were wrapped in the straw bags or styropol and they were placed on the ground or kept in the basement, 7) In most case (80.9%), the salt concentration of pickling was adjusted by one's experiences, and only 19% of them was measured with the instruments. 8) Most of remaining kimchies were usually used for other cooks, but some of them were thrown away. 9) The ratio of the people who had ever bought the market Kimchies for their own edibility was 17.8% and most of them got it only in the spring and summer season. 10) About 18% of the residents living in the general houses in Seoul had ever bought the market Kimchies. It was also known that about 48% of the residents living in the general houses and about 79% of the residents living in the apartments wanted to purchase the market Kimchies if the production of the delicious Kimchies were industrialized. The season that the people wanted to get the market Kimchies was a little different each other among the residents. About 13.4% of the residents living in the general houses wanted to purchase the Kimchies during the summer, and 11.9% of them wanted to get it throughout the year. On the other hand, in case of the apartments, 25.2% of the residents wanted to get it during the summer and 24.4% of them wanted it throughout the year (4 seasons) and 19.9% of them wanted it during two seasons. The data mentioned above have shown that many residents hope strongly an industrial production of the Kimchies. It is also true that many residents living in both the general houses and apartments want to get the market kimchies throughout the year, and particulary during the summer season that most foods are very apt to be spoiled.

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The Effects of Protozoa on the Early Formation of Microbial Fouling Communities of Inchon Coastal Waters (인천 연안 미세오손생물 군집 형성과 원생동물의 영향)

  • Choi, Joong-Ki;Yang, Eun-Jin;Lee, Won-Je;Yoon, Won-Duk;Shim, Jae-Hyung
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.4 no.4
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    • pp.349-362
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    • 1999
  • To understand the role of protozoa in the early formation of microbial fouling community, the studies on the formation of microbial film, the succession of microbial fouling communities, and the grazing pressure on bacteria population in microbial film were carried out in the laboratory, Inchon outer port and Inchon inner harbour. Bacteria and heterotrophic flagellates formed primary microbial film on the aluminum surface within 6 hours and oligotrich ciliates were observed 2 cells $mm^{-2}$ on the same surface at 9 hours in Inchon inner harbour which had physically stagnant condition. The larvaes of Balanus albicostatus which were dominant meiobenthos in Inchon coastal area attached on the glass surface at the first day of experiment. Heterotrophic flagellates showed maximum abundance of 465 cells $mm^{-2}$ at the 13rd day and ciliates showed maximum abundance of 63 cells $mm^{-2}$ at the 11st day in the Inchon inner harbour. In the Inchon outer port which opens to the outer sea, the maximum abundance of protozoa occurred at early phase, but not so many. The dominant heterotrophic flagellates were Metrornonas simplex and Bodonids. Dominant ciliates were small tintinnids and oligotrich ciliate Strombidium sp., Large Strombidium (oligotrich ciliate) and sessile Acineta turberosa (suctorian ciliate) occurred after 10 days. The attached larvae of Balanus occurred as biofouling organism on the early surface and showed maximum abundance of 18 indiv. $cm^{-2}$ at 7th day. At that time, adult barnacles were observed on the surface and dead barnacles were observed after two days. Except barnacles, the larvaes of Anthozoa sp., Oysters (Crassostrea gigas) and Polychaeta were observed on the surface from 3rd day. 3 benthic copepods including Harpacticus sp., I isopod, 1 polychaeta and 1 gastropoda were observed as predators of the microbial film on the surface after 7 days when microbial film developed very well. Although the ingestion rates of protozoa on the bactctia of the rnicrobi31 film were relatively low, the average grazing rate of protozoa on bacteria was high of 0.058 $h^{-1}$. This implied that the grazing pressure of protozoa influences the mortality of bacteria populations on the microbial film. but protozoa cannot get enough energy from only bacteria on the microbial film.

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Marine Bacteriological Quality and Dynamics in Tongyeong Coastal Area, Gyung-nam, Korea (통영연근해역의 해양세균학적 수질 및 동태에 관한 연구)

  • 최종덕
    • Journal of Food Hygiene and Safety
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    • v.14 no.4
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    • pp.372-379
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    • 1999
  • A bacteriological study of sea water and oyster in Tongyeong coastal area was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria fur the designated area of shellfish cultivation. The Samples were collected at 5 zone, 34 sampling stations(Fig. 1) established once a month from September 1997 to August 1998. During the study period, temperature ranged from 6.9 to 23.6$^{\circ}C$, transparency ranged from 2.6 to 6.2 m, chemical oxygen demand ranged from 1.35 to 1.82 mg/ι, dissolved oxy-gen ranged from 5.0 to 9.9 mg/ι, dissolved nitrogen ranged from 1.60 to 8.17 $\mu\textrm{g}$-at/ι, phosphate ranged from 0.14 to 1.21 $\mu\textrm{g}$-at/ι, Chlorophyll-a ranged from 2.03 to 69.9 mg/㎥, respectively. The coliform group and fecal coliform MPN's of sea water were ranged from <3.0~1,600 and <3.0~540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18~16,000 and <18~2,200, respectively. The viable cell counts in oyster ranged from $1.5\times$10$^2$to 8.2$\times$10$^3$. The coliform stoup, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. 437 strains that were obtained from Tongyeoung coastal area seawater samples represented E. coli group 47.5%, C. freundii group 14.8%, K. aerogenes 10.9%, unknown 26.8%, respectively. During the study period, infectious bacteria such as Vibrio ohoEerae, Salmonella sp. and Shigella sp. were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnificus were 12~21% in summer months.

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Bacteriological Study of Sea Water and Oyster in Charan Bay, Korea (자란만의 해수 및 굴의 세균학적 연구)

  • CHOI Jong-Duck;JEONG Woo-geon;KIM Poong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.3
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    • pp.429-436
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    • 1998
  • A bacteriological study of sea water and oyster in Charan Bay was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria for the designated area of shellfish cultivation, The Samples were collected at 23 sampling stations(Fig. 1 and Fig. 2) estaslished once a month from January 1997 to December 1997, During the study period, temperature ranged from 4.7 to $25.6^{\circ}C$, transparency ranged from 3.3 to 6.2m chemical oxygen demand ranged from 1.67 to 2.18 mg/$\ell$, dissolved oxygen demand ranged from 5.4 to 10.0 mg/$\ell$ dissolved nitrogen ranged from 1.65 to 7.88 $\mu$g-at/$\ell$, phosphate ranged from 0.15 to 1.16 $\mu$g-at/$\ell$, Chlorophylla-a ranged from 0.95 to 12.69mg/$\ell$. The coliform group and fecal coliform MPN's of sea water were ranged from <1.8$\~$l,600 and <1.8$\~$540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18$\~$16,000 and <18$\~$1,400, respectively. The viable cell counts in oyster ranged from $1.5\times10^2$ to $7.5\times10^3$. The bacteriological criteria of sea water in shellfish growing area should be less than 70 per 100 ml of sea water for median value of coliform MPN, and below $10\%$ of the samples which contain over than 230 for coliform MPN or over than 43 for fecal coliform MPN. The sea water from 432 samples were complied water coliform criteria recommended for designated shellfish growing area. The coliform group, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. During the study period, infectious bacteria such as Vibrio cholerae, Salmonella sp, and Shigella sp, were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnifirus were $7\~17\%$ in summer months.

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Epizootiology of Perkinsus sp. Found in the Manila Clam, Ruditapes philippinarum in Komsoe Bay, Korea (곰소만에 있어 바지락포자충, Perkinsus sp.의 출현에 관하여)

  • PARK Kyung-Il;CHOI Kwang-Sik;CHOI Jin-Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.3
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    • pp.303-309
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    • 1999
  • Mass mortality of the Manila clam, Ruditapes philippinarum has been reported all along the west and south coast of Korea for the past several years. As a pathogenic agent, Perkinsus sp., an endoparasitic protozoan has been identified in this study and believed to be responsible for the mass mortalities. Prevalence and infection intensity of Perkinsus sp. was investigated from a Manila clam population inhabiting at Komsoe Bay in the west coast where mass mortality of the clam has been reported. A total of 142 Manila clam, 50 oyster, Crassostrea gigas, 10 ark shell, Scapharca broughtonii, and 5 predatory gastropada, Rapana venosa were examined for the presence and the quantity of Perkinsus sp. Ray's fluid thioglycollate medium method (FTM method) with modified Mackin's infection intensity scale and Choi's quantitative method were used in detecting and quantifying the parasite. All individuals of R. philippinarum examined in this study were infected with Perkinsus sp., indicating $100\%$ prevalence while none of the oysters and the gastropods exhibited the parasite. Six to ten individual hypnospores of Perkinsus sp. were counted from the ark shells. The number of hypnospores in the clam tissues varied from 16,667 to 4,091,667, with a mean number of 1,077,628. Average infection intensity according to Mackin's was 2.87, indicating a moderate infection. A negative correlation was observed between the number of Perkinsus sp. in the tissue and the condition index, a ratio tissue wet weight to shell cavity volume. The clam size and the infection intensity in terms of total number of parasites were positively correlated; the bigger clam, the heavier infection. Such high number of Perkinsus sp. counted in the clams could be enough to cause physiological disturbance of clams, such as retarded growth and reproduction. It is also believed that such a high infection leads mortality of the clam via continuous draining of the energy by metabolic activities and reproduction of the parasites. Correlation between the condition index and the infection intensity observed in this study supports this hypothesis.

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A Study on the Cooking in 'The Kosa-sibi Jip' (2) ("고사십이집(攷事十二集)"의 조리가공에 관한 분석적 연구(2))

  • 김성미
    • Journal of the East Asian Society of Dietary Life
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    • v.4 no.3
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    • pp.1-19
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    • 1994
  • In this paper, twenty-five kinds of food presented in Sooljip(戌集) 5 and 6 of Food collections of 'Kosa-sibi Jip(攷事十二集)' have been classified into four : Staple food, subsidiary food, Tuck(rice cake) and Han-gwa(Korean confectionery), and Tang-jng and tea. Cooking processes have been examined and scientifically analyzed in terms of cooking, Fourteen kinds of Jook (thick gruel with cereal) as well as Urak-Jook were presented among the methods of making Jook, one of staple foods. Milk and ground rice were boiled together into Urak-Jook, which was nutritious because of carbohydrate, added to milk. Hong-sa Myun was mode of ground shrimps, ground bean, ground rice and flour which were kneaded together. It was a nutritiously balanced food. Nineteen kinds of Kimchi presented in this book were classified by the recipes. The five of Jook-soon Ja, U-so Ja, Tam-bok Ja and Jo-gang were made by adding red malt and cereals(boiled rice or candies). Jo-gang, Jo-ga and Jo-gwa-chae were made by adding salt and rice wine. With salt and fermenters added, eight were made. Chim-jup-jeo-ga was made by adding Jang(soy-bean sauce) and the inner chaff of wheat instead of salt. The four of Ka-za-san, Hwang-gwa-san, Tong-gwa-san and Jo-gang were made by adding salt and vinegar. Jo-gang was made by adding salt, rice wine, residue of rice wine and candies. The four of Kae-mal-ga, Ku-cho-chim-chae, Un-gu-hwa and Suk-hwa-chim-chim-chae were made by adding salt and spices. San-got-Kimchi was made without salt. San-got-Kimchi and Suk-hwa-chim-chae were made originally in Korea. Suk-hwa-chim-chae, in particular, was first classified as a kind of Kimchi in this book and oysters were added, which is notable. Pork could be preserved longer when smoked oven the weak fire of thatch ten days and nights. Dog meat was sauced and placed on the bones in a pot. A porcelain was put on the top of the pot. Flour paste sealed the gap between the porcelain and the pot. Some water was poured into the porcelain, and the meat was steamed, with two or three thatched sacks burned, which was a distilled dry steaming. This process has been in use up to now. Various cooking methods of chicken were presented from in Umsik-dimi-bang to in Chosun Musang Sinsik Yori Jebup. These methods were ever present regardless of ages. Such measuring units as Guin(斤) and Nyang(兩) were most frequently used in cooking processes of this book, except in case of Jang(soy bean sauce), vinegar and liquor. Twenty eight kinds of kitchenware and cookers were used, of which porcelains wee most used and pans and sieves followed. The scientific eight cooking methods were as follows. First, salt was refined through saturated solution. Next, it was recommended Hong-sa Myun containing shrimps should not be taken along with pork, which is thought to be a proper diet in terms of cholesterol contained by shrimps and pork. Third, meat was coated with thin gruel and quickly roasted and cleared of the dried gruel membrane, which prevented nutrients from exuding and helped to make the meat well-done. Fourth, The fruit of paper mulberry trees has the protease which can soften meat. Therefore when meat was boiled with th fruit of paper mulberry trees, it can be softened easily. Fifth, pork was smoked over the weak fire of thatch. Sixth, in cooking dog meat, distilled dry steaming raised the boiling point and made it possible to preserve meat longer. Seventh, in boiling the sole of a bear, lime was added, which made meat tender by making the pH lower or higher than that of raw meat. Finally, in boiling down rice gluten, a porcelain in the pot prevented boiling over the brim, which is applied to pots in which to boil medical herbs.

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Detection of Megalocytivirus in shellfish using PCR with various DNA extraction methods (다양한 PCR용 DNA 추출법에 의한 패류 내 Megalocytivirus의 검출)

  • Kim, Jin-Woo;Cho, Mi-Young;Jin, Ji-Woong;Kim, Ki-Hong;Jeong, Hyun-Do;Kim, Kwang-Il
    • Journal of fish pathology
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    • v.24 no.2
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    • pp.65-73
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    • 2011
  • In analysis of DNA viruses from the contaminated shellfish using PCR, preparation method of template DNA is an important factor to get enough copy number of viruses. In this study, we evaluated the efficiency of PCR template of Megalocytivirus (sT50mg-D) DNA obtained from 50 mg digestive gland homogenate of oyster using commercial method, and compared with that obtained from 5 g of the same tissues (T5g-D) after PEG precipitation procedures of virus. Both templates DNA suspended in the same volume of distilled water showed positive results by primary PCR with 35 cycles, and the presence of Megalocytivirus was confirmed in oysters collected from cultured farms in Korea. Moreover, PCR with sT50mg-D allowed us to discriminate the contaminated oyster individually, that can not be done in PCR with T5g-D prepared from the mixture of three different individual oyster to get 5 g digestive gland homogenate. In quantitative analysis with real time PCR, Megalocytivirus concentrations in 50 ${\mu}l$ templates prepared using 0.5~50 mg of one positive sample were appeared in the range 6.14E+00~1.2E+02/${\mu}l$. We were not able to get positive result using template DNA contained less than 6.14E+00 copies. Consequently, 2-step PCR performed with DNA extracts from oyster homogenate of small amount (sT50mg-D) i) was enough to detect the contaminated Megalocytivirus in shellfish, ii) allowed us to do the analysis for individual shellfish rather than mixture of several shellfish and iii) showed the presence of Megalocytivirus in oyster from Korea.