Bioassay and Preliminary Characterization of Ovigerous-Hair Stripping Substance (OHSS) in Hatch Water of Crab Larvae

Abstract

Hatch water (the filtrated medium into which zoea larvae have been released) of the estuarine terrestrial crab Sesarma haematocheir (akate-gani) contains a substance that causes premature detachment of embryos from ovigerous females. Detachment occurs when the ovigerous hairs along the female's ovigerous setae slip out of the investment coat that binds them to the embryos through stalks, or funiculi. The active factor, which I call ovigeroushair stripping substance (OHSS), is released outside of the egg capsule at the time of hatching, and is not secreted by the female. This study describes the results of a quantitative assay for measuring the activity of OHSS. Activity is measured as the percentage of hairs on a seta that can be induced to slip out of the coat without damage. Experiments with an extract of crushed embryos indicated that OHSS is present up to 2 days before hatching. Its activity was destroyed by heat and trypsin, suggesting that it is a protein. Its molecular size was estimated by gel filtration to be 15-20 kDa in S. haematocheir and 30 kDa in S. pictum. Reciprocal tests among different species indicated that OHSS occurs widely in intertidal and estuarine crabs.

Screening of genes related to ovarian development in the swimming crab, Portunus trituberculatus, by suppression subtractive hybridization

“…Up-regulated expression level of histone h3 in the mature ovary may be beneficial to the developmental of the ovary. Ovigerous-hair stripping substance (OHSS), released by the embryo upon hatching (Gusev et al, 2004), plays a role in the stripping of the embryo attachment system from the maternal ovigerous hairs following hatching, in preparation for the next clutch of embryos (Saigusa, 1995). Ovary development related protein was firstly cloned in Eriocheir sinensis (AEC22817), and was up-regulated in the mature ovary.…”

Purification and cDNA cloning of the ovigerous-hair stripping substance(OHSS) contained in the hatch water of an estuarine crab Sesarma haematocheir

“…Most females incubate their next clutch of embryos a few days after larval release (Saigusa et al, 2002). The females were therefore kept in the laboratory for about 2 months, and hatch water was obtained from their second larval release (for further details, see Saigusa 1995Saigusa , 1996.…”

“…Shortly before the bioassay, the fixed ovigerous setae were suspended in DW to wash out the ethanol, and then placed in a glass dish with DW. The ovigerous seta was subdivided into four segments under a stereomicroscope (for further details of biological assay, see Saigusa, 1995). Crab ovigerous-hair stripping substance…”

“…the filtered medium in which zoea larvae are released by the female), caseinolytic proteases and OHSS (ovigerous-hair stripping substance) (Saigusa, 1996). OHSS plays a role in the stripping of the embryo attachment system from the maternal ovigerous hairs just after hatching, in preparation for the next clutch of embryos (Saigusa, 1995). OHSS is clearly secreted by the embryo and not by the female (Saigusa, 1995).…”

“…OHSS plays a role in the stripping of the embryo attachment system from the maternal ovigerous hairs just after hatching, in preparation for the next clutch of embryos (Saigusa, 1995). OHSS is clearly secreted by the embryo and not by the female (Saigusa, 1995). However, physiological mechanisms by which the stripping of ovigerous hairs is caused by OHSS are not known.…”