Malays. Appl. Biol. (June 2004) 33(1): 47-52
EFFECTS OF TRYPSIN ON CROSS-FERTILIZATION CAPACITY
AMONG SEA URCHINS, TRIPNEUSTES GRATILLA, PSEUDOBOLETIA INDIANA AND TOXOPNEUSTES PILEOLUS
SK. MUSTAFIZUR RAHMAN, TSUYOSHI UEHARA* and YUJI HIRATSUKA
Graduate School of Science and Engineering,
University of the Ryukyus,
Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
ABSTRACT
The effect of trypsin on cross-fertilization capacity of egg was studied with three species of sea urchins, Tripneustes gratilla, Pseudoboletia Indiana, and Toxopneustes pileolus. Among the three species, cross-fertilization appeared to be asymmetrical, indicating the presence of strong gamete recognition protein and species specificity of the sperm-egg attachment. However, when the eggs of these species were exposed to a limiting concentration of trypsin (0.001 %) for a few minutes and then inseminated with sperm, the eggs appeared to be fertilized to a level almost equal to that in the corresponding conspecific fertilization. These results suggest that trypsin destroy the species-specific barrier, located on the vitelline layer through limited proteolysis, which is known to prevent heterospermic fertilization. This is the first attempt to cross-fertilize among these species by treating trypsin protein. This technique might be helpful to produce viable hybrids in future for potential use in aquaculture.
ABSTRAK
Kesan tripsin ke atas keupayaan persenyawaan silang pada telur bagi tiga spesies landak laut Tripneustes gratilla, Pseudoboletia Indiana and Toxopneustes pileolus telah dikaji. Pada ketiga-tiga spesies tersebut didapati berlaku persenyawaan silang secara tidak simetri dan ini menunjukkan wujud protein garnet tertentu dan spesies-spesifik dalam proses perlekatan sperma-telur. Walau bagaimanapun apabila telur daripada ketiga-tiga spesies didedahkan kepada kepekatan tertentu tripsin (0.001 %) untuk beberapa minit dan kemudian dieram bersama sperma, didapati telur berjaya disenyawakan. Keputusan kajian ini mencadangkan bahawa tripsin telah memusnahkan halangan spesies-spesifik yang berada pada lapisan vitelin telur melalui proses proteolisis yang diketahui bertindak sebagai pelindung kepada fenomena persenyawaan heterospermi. Kajian ini merupakan kajian pertama yang melibatkan persenyawaan silang di antara spesies melalui tindakan protein tripsin. Teknik ini mungkin dapat membantu penghasilan hibrid yang viabel pada masa akan datang untuk kegunaan dalam akuakultur.
Key words: Sea urchin, Cross-fertilization, Trypsin, Vitelline layer, Species-specific.
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