• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.167-168
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• 2006

Chemotaxis, or preferential motion due to presence of a chemical gradient, is an important factor in sperm fertilization of eggs in that it is the first interaction between sperm and egg. In the present study, we aim to quantify the possible chemoattractive role of the jelly coat. The chemotaxis of the sperm of sea urchin was demonstrated with the effective motility coefficient by a microfchannel made of polydimethysiloxane (PDMS). The relevance of these findings is that they provide insight on the first steps towards egg fertilization.

• Development and Reproduction
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• v.2 no.2
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• pp.149-155
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• 1998

The polysialic acid (polySia) glycotope covalently modifies cell surface glycoconjugates on cells as evolutionarily diverse as microbes and human. The recent chemical identification of polysialylated glycoproteins in the jelly coat and on the cell surface of the sea urchin egg raises important questions about their biosynthesis and possible function. Using CMP-[$^{14}$ C]Neu5Ac as substrate and cell free preparations from eggs and embryos of the sea urchin Stronglylcentrotus nudus, we have identified a membrane associated CMP-Neu5Ac:poly-$\alpha$2, 8 sialosyl sialyltransferase (polyST) that transfers Neu5Ac to an endogenous acceptor. Optimal conditions for the polyST activity were found to be 2$0^{\circ}C$ in 20 mM MOPS buffer (pH 7.0). The polyST activity was increased 2.7 times by the addition of 10 mM $Mg^2$$^{+}$. The membrane-associated polyST also catalyzed the polysialylation of mammalian ganglioside GD3. Given that no structurally similar natural polysialylated gangliosides have been described, nor were observed in the present study, we conclude that a single polyST activity catalyzes sialylation of the endogenous acceptor and the gangliosides. Using an excess of GD3 as an exogenous acceptor, it was established that the expression of the polyST in S. nudus embryos increased rapidly at the mesenchyme blastula stage and reached at maximum at the gastrula stage. The finding that this polyST in the sea urchin embryo is developmentally regulated raises the possibility that it may play a role in the changing cell and tissue interactions that occur during gastrulation and the early stages of spicule formation.n.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.112-119
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• 2007

A histological study on development and transformation of the oocyte' follicle cell for Korean four sillurid fishes, Liobagrus obesus, L. mediadiposalis, Pseudobagrus koreanus, and P. brevicorpus was performed by light and electron microscopes. The follicular layer surrounding the oocyte consisted of an outer theca cell and an inner follicle cell (granulosa cell). The follicle cells of the oocyte were flatten cells at early oocyte but during vitellogenesis they were transformed it to a single layer of cuboidal cell, then to a single columnar cell layer, and finally to a layer covered with a substance secreted by themselves. Although the development and transformation of the follicle cells was similar to four species, the secreted materials, called an adhesive membrane, were divided into two types in its appearance and nature. Firstly, a jelly coat-like type was found in L. obesus and L. mediadiposalis, which they are presumed to be polysaccharides and mucoproteins in its nature and secondly, a granular type in P. koreanus and P. brevicopus, being mucoprotein. A zona radiata with about $0.6{\sim}3.1{\mu}m$ thin was present below the adhesive material secreted by the transformed-follicle cell's activity. The zona radiata was composed of two layers, a thin externa and a thick interna.