Two bacteria strains were isolated from emaciated olive flounder (Paralichthys olivaceus) in aquafarm and were identificated as Vibrio harveyi (JV1) and Edwardsiella tarda (JE1), respectively. In the challenge experiments, we found 100% cumulative mortalities in all of olive flounder injected with JV1, JE1 or JV1+JE1 within eleven days after the injection. Two bacteria strains were reisolated from dead fish and were analyzed using the PCR method. In the physilogical analysis, the hematocrit, AST, ALT and cholesterol levels in experimental groups were increased significantly compared to those in control group, but the glucose, total protein and triglyceride levels were significantly decreased. Additionally, the lysozyme activity in the blood serum was decreased. The histopathological observations of the intestine showed that all groups had detachment and destruction of epithelial tissues except for the control group.
어류의 면역반응에 대한 cadmium (Cd)의 영향을 분석하기 위하여 넙치 (Paralichthys olivaceus)를 각기 다른 방향으로 Cd에 노출시킨 후 특이적 면역반응의 변화와 Edrwrdsiella tarda KFE (E. tarda KFE)의 인위감염에 대한 저항성을 분석하였다. E. tarda KFE의 formalin killed cell (FKC)로 면역시키기 2주전부터 계속하여 실험 기간동안 침지법으로 Cd(20ppb)에 노출된 시험구는 노출되지 않은 시험구와 양성 대조구보다 혈청 내 특이 항체가가 빠르게 최고치에 이르렀으나, 감소속도는 노출시키지 않은 양성 대조구에 비하여 빠른 것으로 나타났다. 이러한 경향은 splenocytes를 ELISPOT-assay (enzyme-linked immunospot assay)를 이용하여 특이 항체 생성 세포 (specific antibody secreting cell, SASC) 수를 분석해 보았을 때에도 동일하게 나타났다. 그러나 면역 전 2주 동안만 Cd에 노출시킨 시험구에서는 혈청내 항체생성 결과와는 달리 증가된 SASC의 수를 보여 주었다. 그리고 면역 2주 전부터 실험 전기간동안 계속해서 Cd에 노출시킨 넙치를 대상으로 하여 E. tarda FKC 생균으로 인위 감염시켰을 때 100% 폐사율을 보여 주었다. 이것은 Cd에 지속적으로 노출된 어류에서의 방어 체계는 면역반응뿐만 아니라 독성효과도 함께 고려되어야 하는 복합적인 것임을 확인 할 수 있었다.
In this study, the molecular structures of tet(M) and tet(G) carried by tetracycline (Tc) resistant bacteria in intestinal microflora from the imported ornamental fish were characterized and compared with each other depend on the imported countries. Of the total isolates, approximately 8.9% of the Ent-lac+ (lactose fermentative bacteria on coliform media) Tc resistant isolates in fish from three different countries, Singapore, Taiwan and Brazil, were appeared to contain tet (M). Three representative isolates of different countries, Aeromonas spp. JSM-1 (Singapore), JTM-1 (Taiwan) and JBM-1 (Brazil), were isolated and analyzed the molecular structures of tet (M) gene. Interestingly, partial sequence tet (M) genes (1099 bp) in JBM-1 (Brazil) showed 99.5% homology with the tet (M) found in the Vibrio spp. RV16 isolate, obtained from marine fish in Korea and known to carry Tn1545 parent type of tet (M). In contrast, tet (M) gene JSM-1 and JTM-1 showed mosaic structure of Tn1545 and Tn916, and 100% homology with each other. It may suggest the presence of various characteristics in terms of tet (M) gene structure. The determined sequence of the tet(G) from Aeromonas spp. JSG-1 and JBG-1 isolated from Singapore and Indonesia ornamental fish respectively showed similar nucleotide sequence homology but revealed a few nucleotide changes in comparison with the sequence of the prototype tet (G) gene (S52437 in GenBank).
To investigate the causes of emaciation in cultured olive flounder Paralichthys olivaceus in Korea. We performed histological examinations and polymerase chain reaction (PCR) with a new primer set. In most cases, the most severe emaciation was observed in the abdominal area Using PCR on extracted livers, kidneys, spleens, gills, brains, and intestines, we found that areas around the kidneys and intestines were as almost always positive. In significantly ema-ciated fish, PCR was positive in all internal organs except the gills. In addition, the homology of 812-bp nucleotide sequences of the 28S rRNA gene was more than 99% in emaciated fish. Partial homology with Myxobolus spp. and Cystodiscus axonis, whose data were obtained from GenBank was 86% and 88%, respectively. Histological examina-tions detected spores in kidneys and intestines but not in other organs. We also performed cohabitation experiments to determine whether infections could be exchanged among species or only within species. Uninfected olive flounder and red sea bream, Pagrus major, cohabitating with emaciated olive flounder showed 100% and 0% cumulative mor-tality, respectively. Thus the cause of emaciation in cultured olive flounder of Korea is likely due to a new parasite.
The outbreak of viral diseases caused by viral haemorrhagic septicaemia virus (VHSV) and red seabream iridovirus (RSIV) have been reported in cultured olive flounder, Paralichthys olivaceus. VHSV has been a serious viral disease that infects the olive flounders in South Korea. Clinical signs of VHSV infection are skin darkening, abdominal distension and haemorrhages. Outbreaks of fish iridoviral disease was first reported from red seabream, Pagrus major farms in Japan. Recently, iridovirus infection have occurred frequently from olive flounder farms in South Korea. In this study, disease surveillance was performed to monitor the prevalence of VHSV and RSIV in olive flounder in 2014. The samples were collected from 60 different olive flounder farms in Jeju from April, May, September, November and December in 2014. RT-PCR (VHSV) or PCR (RSIV) results showed that VHSV were detected in 5 farms, but RSIV has not been detected in any farms. The migration of olive flounder was restricted for the quarantine in 5 farms of VHS outbreak. The nucleocapsid protein (N) gene and glycoprotein (G) gene sequences of the 5 Korean VHSV isolates were successfully amplified and sequenced. Phylogenetic analysis was performed using the VHSV sequences reported here together comparison with the nucleotide sequences available from the GenBank database. Phylogenetic analysis indicated that most of Korea VHSV belong to the genotype IVa and closely related to the strains from Japan and China.
마이클 그레이브스의 주택작품을 통해 그의 주택 작품 디자인 특성이 어떻게 나타났고 변화했는지를 분석하고 이해함으로서 그의 주택에 대한 이해의 폭을 넓힐 수 있는 기회를 마련하고자 한다. 또한 이 연구를 통하여 앞으로 계획될 그의 다른 기능과 종류의 작품을 이해하고 분석하기 위한 기초적인 자료를 제공하는데 의의를 둔다. 본 연구의 구체적인 연구목적은 다음과 같다. 첫째, 기존의 문헌과 자료를 통해 마이클 그레이브스의 다양한 디자인 어휘들을 파악한다. 둘째, 마이클 그레이브스의 대표적인 주택 사례를 선정하여, 주택 디자인의 특성을 파악한다. 셋째, 마이클 그레이브스의 주택 디자인 특성을 통하여 그의 초기작품에서 현재까지의 작품에 나타난 시대별 변화를 파악한다.
본 연구에서는 넙치 (평균체장 및 무게: 20±2.0cm, 70±5.0 g)에 옥시테트라사이클린(oxytetracycline, OTC)-네오마이신(neomycin, N) 복합제를 25-10 ppm 및 50-20 ppm으로 용해하여 2일 동안, 3시간씩 약욕을 실시하였고, 약물투여 중지 후 1일, 5일, 14일, 40일째에 시험군별로 각각 5마리씩 넙치의 근육을 채취하여 항생제 잔류농도를 조사하였다. OTC와 N 표준용액을 농도별로 희석하여 표준곡선을 작성한 결과 각각 R2= 0.9999, R2= 0.9952로 양호한 직선성을 나타내었고, OTC와 N 회수율은 각각 90∼93%, 88∼95%가 관찰되었다. 잔류농도에 대한 측정결과, OTC와 N 복합제를 25-10 ppm 투여한 시험군에서 1일째 OTC는 0.97±0.084 μg/ml이 검출 되었고, N은 0.118±0.079 μg/ml이 검출되었으나 5일째 이후부터 검출이 되지 않았다. OTC와 N 복합제를 50-20 ppm 투여한 시험군에서 1일째 OTC는 1.324±0.062 μg/ml이 검출되었고 N은 0.788±0.05 μg/ ml이 검출되었으나 5일째 이후부터 검출이 되지 않았다.
We determined the resistance rates of pathogenic bacteria isolated from cultured olive flounder Paralichthys oliva ceus to erythromycin (Em), antibiotic typically used in aquaculture and analyzed the genotypes of resistant bacteria using polymerase chain reaction (PCR). We isolated and utilized 160 isolates of Streptococcus parauberis, 1 of S. iniae, 66 of Edwardsiella tarda, 56 of Vibrio sp. and 23 of unidentified bacteria from presumed infected olive flounder from Jeju Island from March 2016 to October 2017. Of the 306 isolated strains, Em-resistant strains included 33 of S. parauberis, 39 of E. tarda and 2 of Vibrio sp. We conducted PCR to assess the resistance determination of Em-resistant strains. Five different types of Em-resistance genes were detected in the 74 Em-resistant strains: erm (A), erm (B), erm (C), mef (A) and mef (E); erm (A) and erm (B) were detected in 1 (3%) and 24 (72.7%) S. parauberis isolates, respectively. In E. tarda, erm (B) was detected in five isolates (12.8 %) and no Em-resistance genes were detected in the two Vibrio sp. isolates.
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