Autonomous Fluorescence Localized at the Polar Lobe of Eggs of Japanese Oyster, Crassostrea gigas

• Main Author: DENO, Takuya
• Format: Article in Journal/Newspaper
• Language: English
• Published: 大阪教育大学
• Subjects: developmental biology; Crassostrea gigas; polar lobe; cytoplasmic determinants; autonomous fluorescence
• Online Access: http://ir.lib.osaka-kyoiku.ac.jp/dspace/handle/123456789/3265

Under ultraviolet illumination, eggs of Japanese oyster Crassostrea gigas were found to emit specific yellow autonomous fluorescence in the vegetal cortical region of egg cytoplasm. The yellow fluorescing cytoplasm was composed of many granules and they were already concentrated at the vegetal pole region of fully matured oocytes stored in the ovary and remained there after fertilization. During first polar lobe formation, such granules localized at the vegetal cortical region of the lobe that appeared at the vegetal pole of the egg and then incorporated into the CD blastomere at the 2-cell stage. The localization of the granules was still recognizable but gradually became ambiguous during the 2-cell stage and the second polar lobe formation but there was no localization on and after the 4-cell stage. マガキCrassostrea gigasの卵をUV励起の蛍光顕微鏡で観察したところ，植物極表層の細胞質が特異的な黄色自家蛍光を持っていることがわかった。この自家蛍光を発しているのは，その部域に局在する多数の顆粒状構造である。この局在は卵巣内の成熟した卵母細胞で既に認められ，受精後も保持されている。第一極葉形成時にこの顆粒は極葉の植物極表層に局在し，2細胞期にはCD割球に取り込まれる。この顆粒の局在は2細胞期及び第二極葉形成時にも認められるが徐々に不明瞭になり，4細胞期以降にはこのような局在は認められなかった。