|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Embryos of intertidal and estuarine crabs are clustered on the ovigerous seta of the female, and ventilated 2-4 weeks by the female's abdomen. When the embryonic development is complete, hatching occurs and zoea larvae are released into water. This study indicates that the crab hatch water (i.e., the filtered medium into which zoeas were released) contains at least two kinds of active substance : i.e., OHSS (ovigerous-hair-stripping substance) and a proteolytic enzyme. Both factors were easily separated on gel filtration.
OHSS was purified by the combination of three kinds of chromatography : i.e., hydrophobic and anion-exchange chromatographies, and gel filtration. Its molecular size was 12 K in Superdex 75 (Pharmacia), but 35 K in SDS-PAGE.
The proteinase dissolved debris of the egg capsule, suggesting that this enzyme actually acts on it. But this activity was at very low level, compared with casein digestion. This enzyme possibly digest a thin, sticky layr enclosing embryos, and would not act on the thick, tough layr, i.e., the main component of the egg capsule. Accordingly, it would be difficult to suppose that such a small scale dissolution causes the breakage of the egg capsule.