• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.417-420
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• 2015

We investigated the relationship between viability and IGF-1 receptor (IGF-1R) activity in D-shaped and umbo larvae of the surf clam Spisula sachalinensis after treatment with vitrification solution (VS) or freezing. In a toxicity assay, VS1, containing 5 M dimethyl sulfoxide (DMSO), was very harmful to D-shaped and umbo larvae. However, VS2, containing 5 M ethylene glycol (EG), was not harmful to either larval stage. Although VS2 had a promising toxicity test outcome, none of the larvae survived vitrification. After immersion into VSs and freezing, IGF-1R ${\beta}$-subunits were detected in all larvae; however, tyrosine phosphorylation of intracellular ${\beta}$-subunits was detected only in the control and live groups. These results suggest that activation of IGF-1R may influence surf clam larvae viability.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.580-582
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• 2001

The Manila clam, Ruditapes philippinaMm (Pelecypoda: Veneridae) is present along the coasts of Korea, China and Japan. In particular, Recently, due to reclamation of tidal areas along the west coast, marine pollution, and reckless overharvesting of this clam, its standing stock has reduced for a decade. Therefore, it is necessary to manage the population of the clam with a proper fishing regime that will maintain an optimal population size in aqua farm. (omitted)

• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.94-101
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• 2014

Approximately 240,000 tons of waste shells are produced annually in the south and west coast of South Korea. Some of these waste shells (oyster, cockle) are recycled as seeding collector and fertilizer, but most are dumped illegally near the coast. One of the alternative solutions that can economically utilize a large amount of these waste shells is to apply them to the production of construction materials. In this research, the basic physical properties of waste shells such as oyster, cockle, clam, manila clam were investigated, and were used to prepare cement mortar with a 25% replacement ratio of sand. According to the results, the 28 day compressive strength of cement mortar with cockle and manila clam shells was similar to that of plain cement mortar. The compressive strength decreased by about 18% when clam was used. However, the cement mortar with oyster shell showed about a 35% reduction in 28-day compressive strength, and two times the absorption capacity of plain cement mortar. The reduction in compressive strength and the increase in absorption capacity were mostly associated with the porous nature of the oyster shell.

• Toxicological Research
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• v.20 no.3
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• pp.225-232
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• 2004

The suitability of the single cell gel electrophoresis (SCGE) assay as a test for the monitoring of genotoxicity of aquatic environment was evaluated. The SCGE assay was employed to detect DNA damage induced in clam (Spisula sachalinensis) exposed to a direct mutagen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or an indirect mutagen, benzo[a]pyrene (B[a]P). The cells of gill and digestive glands were isolated from clam by homogenization, which was the optimized cell dissociation method, and the level of DNA damage was assessed and expressed as mean tail length. In the gill cells, significant dose- and time-dependent increase was observed in the mean tail length at the concentration from 0.01 to 0.5 ppm MNNG for 96 h. The linear correlation between relative dam-age index (RDI) values was suggested to provide criteria of genotoxicity monitoring for direct acting mutagen. The dose- and time-dependent responses of the digestive glands cells were less sensitive than those of the gill cells. In contrast, the genotoxic response resulting from the exposure of 0.01～1.0 ppm B[a]P to clam revealed a higher sensitivity in the digestive glands cells than the gill cells. The comparison between the time profiles of genotoxic responses in clam and carp, the latter had been obtained in our previous study, indicated that the metabolism of genotoxic compounds in the two aquatic organisms were quite different each other. We conclude that the SCGE assay has the potential as a screening test for routine genotoxicity monitoring of aquatic organisms because of its higher sensitivity and simplicity.

• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.13-19
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• 2003

Genomic DNA from the muscle of marsh clam (Corbicula leana) from Gochang, Muan and a Chinese site was extracted to identify genetic differences and similarity by randomly amplified polymorphic DNAs-polymerase chain reaction (RAPD- PCR). Out of 20 primers, seven primers produced amplified fragments which were consistently polymorphic. A total of 1,246 amplified products were produced of which 530 were polymorphic $(42.5\%)$. The number of polymorphic bands produced per primer varied from 40 to 122 with an average of 75.7 in marsh clam from Gochang. 3.28 of the 23.0 polymorphic bands per lane were found to be polymorphic. Also, about $4.34\%$ of total polymorphic bands were specific to marsh clam from Gochang. The major common bands of 0.28 kb generated by primer OPB-15 (GGAGGGTGTT) were present in every individuals, which were polymorphic. This common bands in every individuals should be diagnostic of specific strains, species and/or their relatedness. Primer OPB-19 (ACCCCCGAAG) produced the highest number of 12 specific bands. The intra-population variation was revealed in the band patterns identified by this primer. The random primer OPB-12 (CCTTGACGCA) yielded the amplified fragments which were consistently polymorphic between the marsh clams from Gochang and from Muan. This primer produced a total of 77 polymorphic bands: 31 bands from Gochang, 14 from Muan and 32 from the Chinese populations. An average of polymorphic bands were 1.8 from Gochang and 2.5 from the Chinese populations. This value obtained from the Chinese population was higher than those from the two domestic populations. Generally, the RAPD polymorphism generated by these primers may be useful as a genetic marker for strain or population identification of marsh clam.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.768-773
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• 1996

The changes in amino acid contents of sea mussel and baby clam during drying at 40, 50 and 6$0^{\circ}C$ and storage at low temperature(4$^{\circ}C$) and room temperature(2$0^{\circ}C$) were investigated. Amino acids of 17kinds were analyzed in sea mussel and baby clam. Total amino acids content of raw sample were similar to sea mussel and baby clam(6575.30mg%, 6764mg%), decreased during drying and rate of decreasing was higher in baby clam than that of sea mussel. The content of Glx was highest in sea mussel(790.55mg%) and baby clam(990.89mg%), other amino acids differed from samples. The content of amino acids of low drying temperature(40 and 5$0^{\circ}C$) decreased was higher than that of high drying temperature(6$0^{\circ}C$). The rate of decreasing was higher at room temperature(2$0^{\circ}C$) storage and short storage periods than that of low temperature(4$^{\circ}C$) storage and long storage periods.

• 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.

• The Korean Journal of Zoology
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• v.9 no.1
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• pp.7-15
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• 1966

In a previous paper, the dirunal and monthly changes of the tidal flat temperature and chlorinity were observed. In this paper the resistance of the young short necked clam in various growth stages to the temperature, to the chlorinity and to the exposure were studies. The young clam used were in early (E), medium (M) and late (L) young stages whose shell lengths were 2.0-3.5mm, 9.0-11.0mm. and 14.0-16.0mm., respectively. The results were : 1. At various sea water temperatures , the chlorinity resistance of the young clam was directly proportional to the shell length. 2. When both inadequate sea water temperature and abnormal chlorinity are simultaneously applied, the resistance of these young clams was more markedly reduced than the case of applying either one of these conditions. 3. In clams of M and L, no lethal effect were observed when daily immersion of four to eight hours for a week into the sea water of any concentration of chloriity at 26-34$^{\circ}C$, whereas in E, 37-90% of mortalities were obtained by immersion of eight hours daily into both the fresh water and the sea water of higher chloriniites (more than 23.5$\textperthousand$ Cl) at the same temperature above. 4. The lower critical thermal maximum for lethal to the young clam was 38$^{\circ}C$. With four hours immersion daily at the water temperature of 38$^{\circ}C$, the mortalities of E, M and L to the lower chlorinities (less than 6.7$\textperthousand$Cl) were 100, 70-100 and 27-37% respectively ; to the higher chlorinities (more than 23.5$\textperthousand$Cl) 10-70, 10-37 and 3 % respectively ; to the normal range of chlorinities (13.4-16.8$\textperthousand$Cl) 0-13, 3 and 0 % respectively. 5. No lethal effects were observed in E and M clams immersed continuously for seven days in sea water with chlornities of 7.2 -21.7$\textperthousand$Cl at 18-24$^{\circ}C$, while notable mortalities were observed in E which had been kept at lower (less than 4.8$\textperthousand$ Cl) and higher (more than 24.1$\textperthousand$ Cl) chlorinites. 6. Although the resistance of the young clam to the chlorinity may have to be related closely to the life history of the clam prior subject to the experiment, the adapted chlorinity range was 7.2-19.3$\textperthousand$ Cl and the optimum range was 13.4-16.8$\textperthousand$Cl. 7. Remarkable lethal effects were observed for the E and M clams to the exposure temperature of 38$^{\circ}C$ whereas the L and had no such fatal results.

• Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.98-100
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• 2001

• Proceedings of the Malacological Society of Korea Conference
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• 2003.11a
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• pp.31-31
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• 2003