Littlefield C L
Dev Biol. 1986 Oct;117(2):428-34. doi: 10.1016/0012-1606(86)90311-8.
The stability of sexual phenotype was examined in a single clone of Hydra oligactis males maintained at two culture temperatures, 18 and 22 degrees C. At these temperatures animals of this species do not reproduce sexually, but reproduce asexually by budding, and males and females are morphologically indistinguishable. When the temperature is lowered to 10 degrees C gametogenesis is induced and sexual phenotype can be assayed. Males cultured for several years at 18 degrees C expressed a stable sexual phenotype when induced to undergo gametogenesis; males remained male. Those cultured at 22 degrees C for 1 year, however, expressed a low frequency of sex reversal from male to female; males ceased sperm differentiation and began producing eggs. Male sex reversal in cultures maintained at the higher temperature was correlated with the loss of a specific subpopulation of interstitial cells, those that bind the monoclonal antibody, AC2, which labels cells specific to the spermatogenic pathway in H. oligactis males. When interstitial cells restricted to this pathway were reintroduced into sex-reversed males (phenotypic females), the male phenotype was reestablished and animals reverted to sperm production. To further investigate the role of AC2+ cells in the masculinization of females, normal males (containing AC2+ cells) and sex-reversed males (lacking AC2+ cells) were grafted to females. In grafts between normal males and females, egg production ceased and sperm differentiation ensued, whereas those between sex-reversed males and females continued to produce eggs. Thus, the presence of AC2+ interstitial cells is strictly correlated with male sexual phenotypes and it is only in their absence that the female phenotype is expressed.
在两种培养温度（18摄氏度和22摄氏度）下维持的单克隆寡柄水螅雄性个体中，对其性表型的稳定性进行了研究。在这些温度下，该物种的动物不会进行有性繁殖，而是通过出芽进行无性繁殖，并且雄性和雌性在形态上无法区分。当温度降至10摄氏度时，会诱导配子发生，并且可以检测性表型。在18摄氏度下培养数年的雄性个体，在诱导其进行配子发生时表现出稳定的性表型；雄性个体仍然保持雄性特征。然而，在22摄氏度下培养1年的雄性个体，出现了从雄性到雌性的低频率性逆转；雄性个体停止精子分化并开始产卵。在较高温度下维持培养的雄性个体发生性逆转，与特定间质细胞亚群的丧失有关，这些间质细胞能与单克隆抗体AC2结合，AC2可标记寡柄水螅雄性个体中精子发生途径特有的细胞。当局限于该途径的间质细胞被重新引入性逆转的雄性个体（表型为雌性）时，雄性表型得以重新建立，动物恢复精子生成。为了进一步研究AC2 +细胞在雌性雄性化中的作用，将正常雄性个体（含有AC2 +细胞）和性逆转的雄性个体（缺乏AC2 +细胞）移植到雌性个体上。在正常雄性个体与雌性个体之间的移植中，产卵停止，精子分化随之发生，而在性逆转的雄性个体与雌性个体之间的移植中，动物继续产卵。因此，AC2 +间质细胞的存在与雄性性表型严格相关，只有在其不存在时才会表达雌性表型。
