Centriolar Behavior and Flagellum Formation in Cell Culture System of Testicular Cells of the Sea Urchin

以培养的海胆睾丸细胞为材料，研究了雄性生殖细胞成熟分裂过程中的中心粒行为和鞭毛的形成。用Ficoll密度梯度离心法将分离的睾丸生殖细胞分为初级精母细胞和精原细胞、次级精母细胞和精子细胞3种细胞型。然后将每个细胞片段放入培养液中培养。早期精原细胞、初级精母细胞和次级精母细胞内均有鞭毛。在这一阶段，2个中心粒，包括一个基本体，在鞭毛的底部复制形成2对中心粒。在前中期，鞭毛被吸收到细胞质中，在第一次分裂和第二次分裂的两极各有一对中心粒。二次分裂后形成4个具鞭毛的精子细胞，发育为精子。当核分裂被放线菌酮可逆抑制时，初级和次级精母细胞经常萌发2-4个鞭毛。上述结果表明，在海胆的精原细胞和精母细胞中，中心粒的复制与鞭毛的生长有关，然后每对中心粒改变其功能，形成细胞分裂中心。

Centriolar behavior and flagellum formation during maturation division of male germ cells were studied by using of cultured testicular cells of the sea urchin, Hemicentrotus pulcherrimus.1. Isolated germ cells from the testis were divided by Ficoll density gradient centrifugation into the following 3 cell type fractions : the primary spermatocytes together with spermatogonia, secondary spermatocytes and spermatids. Each cell fraction was then cultured in a culture medium.2. A flagellum was detected in the spermatogonia, the primary and secondary spermatocytes at eary prophase. In this stage, 2 centrioles including a basal body duplicate to form 2 paires of centrioles at the base of the flagellum. At the time of prometaphase, the flagellum was absorbed into the cytoplasm and a pair of centrioles was located at each pole of the first and second division. After the second division, 4 spermatids with a flagellum were formed and developed to spermatozoa.3. When nuclear division was reversibly suppressed by cycloheximide, each of the primary and secondary spermatocytes sprouted frequently 2-4 flagella.4. From above-mentioned results, it was concluded that in spermatogonia and spermatocytes of the sea urchin, duplication of the centriole takes place in association with flagellum growth, and then each paired centriole changes its function to form the cell division centers.