• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.144-150
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• 1992

Paralytic shellfish toxins in mussels Mytilus edulis and dinoflagellate Alexandrium tamarene from Jinhae Bay, south coast of Korea were investigated. The mussels collected in March-April, 1989 showed toxicities of 7.5 MU/g of whole meat(31-88 MU/g of the digestive gland) , and those collected in 1990 showed toxicity level of 1.9-9.9 MU/g of whole meat by the standard mouse bioassay. Analysis of toxins by high performance liquid chromatography revealed the presence of gonyautoxin 1-4$(48-76\%)$ gonyautoxin 8 and epi-gonyautoxin $8(C1-C2,\;14-39\%)$, saxitoxin$(1-10\%)$, neosaxitoxin$(l-7\%)$ and trace amount of decarbamoylgonyautoxin 2 and 3(dcGTX2, dcGTX3) in the mussels of 1989. While, Mussels collected in 1990 contained a significantly larger proportion of neosaxitoxin $(44-50\%)$ than did those of 1989. A. tamarense isolated in April 1989 produced the same toxins in culture with slightly higher proportion of Cl, C2, dcGTX2 and dcGTX3 than in the mussels. The difference was within a range of toxin change during accumulation by shellfish and during sample preparation for analysis. It was thus concluded that the dinoflagellate was the cause of toxins in the mussels.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.181-190
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• 2011

This study was investigated to find out the change of reproductive and histological biomarkers of Ruditapes philippinarum exposed to nonylphenol (NP). Experimental period was 16 weeks. Experimental groups were composed of one control condition and three NP exposure conditions (0.05, 0.1, $0.2 mg\;NP\;L^{-1}$). Gonad index was higher in exposure group than control in female and higher in control than exposure group in male. Intersexuality in the NP exposure group was 14.56% with male exhibiting higher ratio than female. Histological analysis of organ system illustrated expansion of hemolymph sinus, loss of striated border of inner epidermis and degeneration of mucous cell in the mantle. In the gill partially disappearance of frontal and lateral cilia, degeneration of mucous cell were observed. Also, hyperplasia of epithelium and disappearance of striated border were observed in the foot. As the concentration of NP increased, the accumulation of lipofuscin increased in the digestive gland. The results of this study suggest that NP induces reduction of survival rate, histopathology and intersex of R. philippinarum. Furthermore, it is indentified that NP functions as an estrogenic effector on the reproduction of R. philippinarum.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.170-176
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• 2003

The effect of xenobiotics on cytochrome P450 (CYP) and 7-ethoxyresorufin-O-deethylase (EROD) in hepatopancreatic microsome of surf clam, Coelomactra anti-quata, were investigated. The microsome isolated from the digestive gland of the surf clam, collected from the east coast of Korea, was in vitro exposed to p, p -DDT (0.1,0.4 and 1.0 mM) for 30 min and 2,3,7,8-TCDD (0.01, 0.04 and 0.1 ppb) and PCB-153 (0.01, 0.04 and 0.1 ppb) for 7 hr. In the case of DDT exposure, the CYP content and EROD activity of 1.0 mM exposure group increased up to about 117% and 120% of the DMSO solvent control group after 10 min. exposure, respectively. After 2 hr exposure of TCDD, the CYP content and EROD activity were also induced to the range of 103∼110% and 121∼139%, respectively. The PCB-153 exposure group showed 107∼115% of CYP content and 129∼140% of EROD activity after 2 hr exposure. Three test chemicals apparently induced CYP and EROD activity in the microsome of surf clam. The inducing potentials depend en the test chemicals.

• Korean Journal of Environmental Biology
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• v.31 no.3
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• pp.204-212
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• 2013

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of $2mg\;L^{-1}$ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of $3mg\;L^{-1}$. Therefore the 5 days-$LC_{50}$ was found to be $3.55mg\;L^{-1}$ (1.86~$4.96mg\;L^{-1}$). However, occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration. The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than $5mg\;L^{-1}$ in comparison to the control group. Therefore, it is presumed that H. roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H. roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.79-86
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• 2001

The apicomplexan parasite, Perkinsus sp., has been reported as a causative pathogen responsible for the mass mortality of the Manila clams, Ruditapes philippinarum in European countries as well as in Korea. Prevalence, infection intensity, histopathologic features and zoosporulation of Perkinsus found in the Manila clams distributed along the coast of Cheju Island were investigated in this study. Clams were collected from nine different beaches along the Cheju Island from May to July in 2000. Ray's Fluid Thioglycollate Medium (RFTM) and Choi's NaOH lysis methods were applied in the diagnosis and quantification of the Perkinsus infection. Prevalence, percentage infection of the parasite examined was 100% in Pyosun, 70% in Sungsan, 63% in Kumneong, 33% in Jongdalri, 21% in Iho, 17% in Moslpo, and 14% in Seogwipo. No Perkinsus was found in the clams collected from Kimnyong and Yongmeo-ri. Infection intensity as a number of Perkinsus cells per gram tissue wet weight (twwt), was 98,430 cells/g twwt in Pyosun, 78,553 cells/g twwt in Sungsan, 18,980 cells/g twwt in Kumneong, 4,290 cells/g twwt in Jongdalri, 1,527 cells/g twwt in Iho, 1,069 cells/g twwt in Moslpo, and 853 cells/g twwt in Seogwipo. Histological preparation of the infected tissues revealed trophozoites of Perkinsus sp., ranged from 5 to 10 ${\mu}{\textrm}{m}$, in diameter mostly distributed in the digestive gland and the gill filaments. Zoospores were discharged from the hypnospore via discharging tube about 2 days after incubated in filtered and aerated seawater. In general, the prevalence and infection intensity of Perkinsus in Cheju Island were much lower than that reported from the western and southern coast of Korea.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.102-108
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• 2008

Many alternative biocidal additives were applied to antifouling paint to replace TBT, and Sea-Nine 211 is one of alternating organic booster compounds used in antifouling paint. In this study, extent of Sea-Nine 211 toxicity on marine benthic bivalve is evaluated. Sea-Nine 211 was injected to surf clam, Pseudocardium sachalinensis, that inhabitate northern part of Gangwon Province, Korea. Survival rate of the clam and xenobiotics metabolizing enzyme activities in digestive gland were measured during 4 day-exposure period. The results were compared with those of TBT exposed clam. There were no mortality of clam in the solvent (DMSO) control group and the three Sea-Nine 211 exposure groups (5, 25, 50 mg kg$^{-1}$ body weight), while the clam exposed to 1, 2 and 5 mg kg$^{-1}$ TBT chloride (TBTC) demonstrated 70, 30 and 0% survival rate, respectively. The Sea-Nine 211 exposure group showed a tendency of cytochrome P450 (CYP) induction according to the exposure duration, on the other hand, CYP content was decreased in the TBT exposure group. NADPH cytochrome P450 reductase activity slightly increase according to the exposure duration in the Sea-Nine 211 exposure group, while TBTC inhibit its activity as CYP content. Moreover, there was no significant change of NADH cytochrome b5 reductate activity in the clam epxosed to Sea-Nine 211. In the TBTC exposure group, its activity increased in early exposure period and then significantly decreased the rest of exposure period. All the results indicate that Sea-Nine 211 demonstrated a tendency to induce CYP level, while TBTC inhibits the CYP level, NADPH cytochrome P450 reductase and NADH cytochrome b5 reductase activities.

• Journal of Life Science
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• v.27 no.4
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• pp.398-407
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• 2017

BTG 1 (B-cell translocation gene 1) gene was first identified as a translocation gene in a case of B-cell chronic lympocytic leukemia. BTG1 is a member of the BTG/TOB family with sharing a conserved N-terminal region, which shows anti-proliferation properties and is able to stimulate cell differentiation. In this study, we identified and characterized the pacific oyster Crassostrea gigas BTG1 (cg-BTG1) gene from the gill cDNA library by an Expressed Sequence Tag (EST) analysis and its nucleotide sequence was determined. The cg-BTG1 gene encodes a predicted protein of 182 amino acids with 57% 56% identities to its zebrafish and human counterparts, and is an intron-less gene, which was confirmed by PCR analysis of genomic DNA. Maximal homologies were shown in conserved Box A and B. The deduced amino acid sequence shares high identity with other BTG1 genes of human, rat, mouse and zebrafish. The phylogenic analysis and sequence comparison of cg-BTG1 with other BTG1 were found to be closely related to the BTG1 gene structure. In addition, the predicted promoter region and the different transcription-factor binding site like an activator protein-1 (AP-1) response element involved in negative regulation and serum response element (SRE) were able to be identified by the genomic DNA walking experiment. The quantitative real-time PCR analysis showed that the mRNA of cg-BTG1 gene was expressed in gill, heart, digestive gland, intestine, stomach and mantle. The cg-BTG1 gene was expressed mainly in heart and mantle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.179-184
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• 2002

Induction of cytochrome P45O (CYP) and 7-etholqresorufin-O-deethylase (EROD) in the microsome exposed to 3-methylcholan-throne (MC), $\beta$-naphthoflavone (BNF) and phenobarbital-Na (PB) was investigated, Microsome was isolated from digestive gland of clam (Coelomactra antiquata) and then exposed to each chemical in concentration range of 0.1 to 1.0 mM for 7 hours. The CYP content and EROD activity in the microsome exposed to each chemical significantly increased compared to the control group. The overall CYP and EROD induction potency was in order of MC>BNF>PB. The induction response of EROD was two times higher than that of CYP level in the microsome exposed to MC, but the induction response of EROD was slightly higher than that of CYP level in BNF and PB exposure groups.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.171-179
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• 2013

Arginine kinase (ArK) is known to play an important role in most invertebrates the level of ATP by phosphorylation of phosphagens in cell and immuninty in living organisms. ArK has been identified in many kinds of organisms ranging from invertebrate to vertebrate. However, no ArK gene has been cloned and investigated from N. samarangae. This leads us to identify ArK cDNA (NsArK) from the expressed sequence tag (EST) sequencing of N. samarangae. Sequence analysis indicated that the coding region of 1,065 bp contains 355 amino acid residues. Molecular phylogenetic analysis shows that NsArK had very high similarities with mollusca and arthropoda. In an attempt to investigate a potential role of NsArK in the digestive gland of N. samarangae, expression patterns were analyzed. RT-PCR analsysis shows that NsArK mRNA is induced in the rane of 1.2 fold at 6 hr by laminarin when compared with the control. The immunnologial and physiological role of NsArK remains to be further investigated in N. samarangae.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.1-8
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• 1990

The present study was focussed mainly on the morphological changes of the glandular tubules in the large intestine according to age of piglets. Samples were taken from large intesine of 1-, 10-, 20-, 35- and 45-day-old piglets, 2 to 3 piglets in each age group. The intestinal samples were fixed in 10% neutral formalin solution, dehydrated, and then paraffin sections were stained with H-E. The results observed were summarized as follows: 1. The mucosal glands in the cecum and colon tend to be unbranched simple straight tubular glands, or often two or more branched simple stright tubular glands. 2. The number of the longitudinal folds and the number of the crypts per cross section of piglet colons, respectively, were 1-day-old piglets-$3.8{\pm}0.8$, $92.1{\pm}6.9$; 10-day-old piglets-$7.1{\pm}1.1$, $164.2{\pm}10.3$; 20-day-old piglets-$15.2{\pm}0.8$, $178.5{\pm}6.8$; 35-day-old piglets-$19.3{\pm}3.0$, $454.9{\pm}25.3$; 45-day-old piglets-$20.6{\pm}3.1$, $524.6{\pm}37.2$, and the regression equation between age and these two number were $\hat{Y}=0.40X+4.32$ and $\hat{Y}=10.4X+51.52$, respectively. 3. The length and cell number per single side wall of a glandular tubule in the colon section were 1-day-old piglets-$196.3{\pm}7.1{\mu}m$, $40.0{\pm}3.3$; 10-day-old piglets-$236.0{\pm}34.5{\mu}m$, $47.9{\pm}5.3$; 20-day-old piglets-$262.8{\pm}39.6{\mu}m$, $54.3{\pm}9.0$; 35-day-old piglets-$291.75{\pm}48.3{\mu}m$, $56.9{\pm}4.9$; 45-day-old piglets-$364.8{\pm}61.5{\mu}m$, $67.7{\pm}7.4$, respectively, and the regression equation between age and these two data were $\hat{Y}=3.45X+193.8$ and $\hat{Y}=0.56X+41.0$, respectively. 4. The overall percentages of the cell number and length of glandular tubules in piglet colons were the pit and isthmus-$75.3{\pm}11.1%$, $78.8{\pm}12.3%$; gland-$24.7{\pm}5.4%$, $21.2{\pm}5.3%$, respectively. 5. The length and cell number of single side wall of glandular tubules in cecal sections were 1-day-old piglets-$190.3{\pm}31.1{\mu}m$, $37.6{\pm}4.8$; 10-day-old piglets-$235.6{\pm}25.3{\mu}m$, $46.2{\pm}3.6$; 20-day-old piglets-$295.3{\pm}45.6{\mu}m$, $52.0{\pm}6.2$; 35-day-old piglets-$351.3{\pm}28.3{\mu}m$, $60.4{\pm}8.5$; 45-day-old piglets-$366.3{\pm}48.5{\mu}m$, $64.7{\pm}8.2$, respectively, and the regression equation between age and these two data were $\hat{Y}=4.11X+196.6$ and $\hat{Y}=0.60X+38.9$, respectively.