Sperm Attractant in the Micropyle Region of Fish and Insect Eggs
Sperm Attractant in the Micropyle Region of Fish and Insect Eggs
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鱼和昆虫卵珠孔区的精子引诱剂
DOI：
10.1095/biolreprod.112.105072
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发表时间：
2013
影响因子：
3.6
通讯作者：
and Kenneth Kaneshiro
中科院分区：
文献类型：
--
作者：
Ryuzo Yanagimachi;Gary Cherr;Takahiro Matsubara;Tadashi Andoh;Tatsuo Harumi;Carol Vines;Murali Pillai;Frederick Griffin;Hajime Matsubara;Tina Weatherby;and Kenneth Kaneshiro
在一些动物中，如鱼、昆虫和头足类动物，厚厚的卵壳有一个狭窄的通道--一个孔洞--精子通过它进入卵子。在鱼类中，没有迹象表明精子被远处的卵子吸引，但一旦精子靠近珠孔的外部开口，它们就会向它定向移动，这表明在这个限定的区域存在吸引精子的物质。由于考马斯蓝(CB)优先结合到比目鱼、鲱鱼、钢头和其他鱼类的珠孔区域，它可能会染色这种精子引导物质。这种物质是一种基于凝集素染色的糖蛋白，与绒毛膜表面紧密结合，但可以通过蛋白酶处理很容易地去除。虽然在去除这种物质后，鱼(比目鱼)的受精是可能的，但缺乏这种物质会使受精效率低下，受精率的急剧下降反映了这一点。精子对珠孔开口的“吸引力”因物种而异，并依赖于细胞外的钙离子。一些昆虫的卵，包括果蝇，有明显的孔帽与CB亲和力，这也可能被证明有助于精子进入。我们尝试让苍蝇卵在体外受精，但没有成功。
In some animals, such as fish, insects, and cephalopods, the thick egg coat has a narrow canal—a micropyle—through which spermatozoa enter the eggs. In fish, there is no indication that spermatozoa are attracted by eggs from a distance, but once spermatozoa come near the outer opening of the micropyle, they exhibit directed movement toward it, suggesting that a substance exists in this defined region to attract spermatozoa. Since Coomassie Blue (CB) binds preferentially to the micropyle region in flounder, herring, steelhead, and other fish, it probably stains this sperm guidance substance. This substance—a glycoprotein based on lectin staining—is bound tightly to the surface of the chorion, but can be removed readily by protease treatment. Although fertilization in fish (flounder) is possible after removal of this substance, its absence makes fertilization inefficient, as reflected by a drastic reduction in fertilization rate. The sperm “attraction” to the micropyle opening is species specific and is dependent on extracellular Ca2+. Eggs of some insects, includingDrosophila, have distinct micropyle caps with CB affinity, which also may prove to assist sperm entry. Our attempts to fertilize fly eggs in vitro were not successful.