• YAKHAK HOEJI
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• v.38 no.4
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• pp.394-400
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• 1994

As a previous step for the development of immunostimulating substance from marine natural products the two new lectins, MLA-II and MLA-III, have been isolated and purified from the hemolymph of Meretrix lusoria in addition to the previously reported MLA-I. The new lectins molecules were characterized as pure by electrophoretic studies.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.243-251
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• 1995

Three new lectins, MLA-I, MLA-II and MLA-III, have been isolatedand purified from the hemolymph of Meretrix lusoria and reported previously. Biophysicochemical characteristics were investigated with these three MLA lectins. The MLA lectins agglutinated human erythrocytes non specifically and proved as D-galactose group carbohydrate specific. Molecular weight of ML.A-I. II and III were estimated to be 330, 500 and 310KD, respectively, by gel filtration on Sepharose CL-6B column. On SDS-polyacrylamide gel electrophoresis, ML.A-I was dissociated into a single subunit of 42KD, MLA-II was into the twelve subunits of 46, 32, 30, 28, 25, 23. 22, 20. 19, 16, 15, and 14KD, and MLA-III was into the two subunits of 72 and 44KD. The pl of MLA-I, II, III were 4.0. 4.9 and 5.0. Amino acid analysis revealed a high contents of acidic and hydroxy amino acids, and a paucity of sulfur containing amino acids. Proline was not contained in MLA-II.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.252-259
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• 1995

Isolation, purification and characterization of biophysicochemical properties of the three new lectins, MLA-I, MLA-II, MLA-III from the hemolymph of Meretrix lusoria have been reported previously. A series of immunochemical studies were investigated in this work. The three lectins were revealed as having partial identity each other by immunodiffusim and immunoelectrophoresis. These results suggest that MLA lectins are isolectins having similar biophysicochemical properties. Particularly, MLA-I proved to be a potent mitogen for murine splenic as well as human peripheral lymphocytes, and the optimum mitogenic dose were 62.5 and 1.95 $\mu\textrm{g}$/ml, respectively.

• Journal of Aquaculture
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• v.21 no.2
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• pp.111-122
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• 2008

This study was conducted to assess the usefulness of the temperature characteristics of the tidal flat sediments during low tide as a environmental factor, and burrowing behaviour, fatness, total hemocyte counts(THCs) and differential hemocyte counts(DHCs) of hard clam Meretrix lusoria as biological activity indices for the management of hard clam farms located in Taean(Chungnam province) and Gimje(Jeonbuk province) tidal flat in Korea. Temperature ranges of the sediment at 1cm depth during spring(March to May) and summer(June to August) in Taean(where the exposure time was about $5.5{\sim}6$ hours during low tide) were $8.7{\sim}26.8^{\circ}C\;and\;27.6{\sim}32.8^{\circ}C$, respectively. Even though there was no significant difference(P>0.05), temperatures of the surface sediment where submerged with remained seawater were generally higher than that of uncovered with seawater. Burrowing depths of normally digged hard clams were 0.9{\sim}3.6cm from March to October, 2002. In the field experiment performed at Taean farming ground covered with seawater, burrowing times of the clams under natural water temperatures were $41.6{\pm}10minutes$ in February and $5.4{\pm}1.3minutes$ in August, respectively, and these were influenced by water temperatures. Fatness of hard clams began to decrease from May(at Taean tidal flat) and June(at Gimje tidal flat), showed the lowest level in August and increased again from September. Total hemocytes counts in the hemolymph of the hard clams were decreased to the lowest level in July($24.7{\times}10^4cells/mL$, at Taean tidal flat) and August($28.2{\times}10^4cells/mL$, at Gimje tidal flat), and significantly increased again from September(at Taean tidal flat, P<0.01) and October(at Gimje tidal flat, P<0.001), respectively. We observed three types of hemocytes from the hemolymph of hard clams according to whether hemocytes retain the granules or not and the size of the granules. As a results, we could found that periodical monitoring of the sediment temperatures, clam burrowing behaviour and hemocyte parameters were very helpful for the management of hard clam farming.