| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1987: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Opisthobranchs are known to have a variety of active copounds which play a role in the defense mechanism. Most of them are derived from their algal diets. We have found that sea hares caontained antibacterial glycoproteins in their fertilized eggs. The active principle, named aplysianin-E had a molecular weight of 250,000 consisted of three subunits with different molecular weights. In this study, we isolated an antibacterial glycoprotein from the albumen gland of Aplysia kurodai. It had a MW of 320,000 consisting of a subunit (78,000 daltons). In spite of the differences in the chemical properties, it showed a partial similarity in the antigenic specificity. The antibacterial activity was detected only in a trocophore larva but not in a veliger form. Analysis of protein components of the fertilized eggs by SDS-polyacryl-amide gels showed the protein bands corresponding to aplysinanin-E disappeared at the stage of veliger larve. These suggest aplysianins serve as a part of defense in early stages of the prehatching development of Aplysia. Similar antibacterial glycoproteins were also isolated from the eggs and the genital mass of A. juliana. The active principles were purified by chromatography on a hydrophobic gel and gil filtration. The active principles thus purified from both organs showed similar properties each other. The molecular weights were 378,000 which split into a subunit having a molecular weight of 78,000. they inhibited the growth of Bacillus subtilis and also that of mouse leukemia cell line, L1210. Ouchterlony double-diffusion tests suggested that these glycoproteins also have a common amino acid sequences in their molecules. These indicate the wide distribution of antibacterial glycoproteins in members of Aplysiidae.
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