有再生迹象的两栖动物Ampeliscaeschrichtii的雌性,先前萎缩的卵巢是从萨哈林岛(鄂霍次克海,俄罗斯)。先前未知任何两栖动物物种的卵巢再生。A.eschrichtii的生命周期主要为2年(从胚胎到成年死亡),并且在2岁时在冬末或早春之间繁殖一次。偶尔,女性存活到第三年。在这些雌性中延长生存的适应性价值可能要求它们也具有生殖能力。
一名二年级女性卵巢萎缩的组织学切片,卵巢正常的女性,一名卵巢再生的三年级女性,比较了未成熟和性成熟男性的睾丸,以确定卵巢再生所需的生发和体细胞系的细胞来源。
三年级女性的卵巢再生开始于由保存在萎缩的卵巢中的生殖细胞和先前饥饿的二年级女性的嗜酸性细胞形成新的生发区。嗜酸性细胞形成生发区的中胚层成分。这些细胞的大量出现在卵巢萎缩的第二年女性中,并且大量出现在卵巢再生的第三年女性的肠壁上。这些嗜酸性细胞似乎迁移到再生卵巢中。
在卵巢萎缩期间,二年级女性的所有生殖细胞都不会丢失,并且可以参与随后的卵巢再生。参与卵巢再生的嗜酸性细胞来自中胚层。嗜酸性细胞形态类似于静止细胞(处于不分裂但保留重新进入细胞分裂并参与再生的能力的可逆状态的细胞)。因此,这些组织学数据表明,三年级女性的嗜酸性粒细胞和生殖细胞可以参与卵巢的再生以繁殖第二个育苗。这些第三年雌性的前体(少数具有异步[夏季]繁殖期和由于季节性饥饿而萎缩的卵巢的第二年雌性)似乎具有足以用于卵巢再生的体细胞和生殖细胞的来源,这可能是对饥饿压力的适应。
Females of the gammaridean amphipod Ampelisca eschrichtii with signs of regenerating, previously atrophied ovaries were recovered from the northeastern shelf of Sakhalin Island (Okhotsk Sea, Russia). Ovarian regeneration was previously unknown for any amphipod species. A. eschrichtii have a predominantly 2-year life cycle (from embryo to adult death) and reproduce once between late winter or early spring at the age of 2 years. Occasionally, females survive to a third year. An adaptive value of extended survival among these females is likely to require that they are also reproductive.
Histological sections from a second-year female with ovarian atrophy, a female with normal ovaries, a third-year female with ovarian regeneration, as well as testes of an immature and a sexually mature male were compared to determine the sources of cells of the germinal and somatic lines necessary for ovarian regeneration.
Ovarian regeneration in the third-year female began with the formation of a new germinal zone from germ cells preserved in the atrophied ovaries and eosinophilic cells of the previously starving second-year female. Eosinophilic cells form the mesodermal component of the germinal zone. A mass of these cells appeared in the second-year female that had atrophied ovaries and in large numbers on the intestine wall of the third-year female with regenerating ovaries. These eosinophilic cells appear to migrate into the regenerating ovaries.
All germ cells of the second-year female are not lost during ovarian atrophy and can be involved in subsequent ovarian regeneration. Eosinophilic cells involved in ovarian regeneration are of mesodermal origin. The eosinophilic cell morphologies are similar to those of quiescence cells (cells in a reversible state that do not divide but retain the ability to re-enter cell division and participate in regeneration). These histological data thus indicate that eosinophilic and germ cells of third-year females can participate in the regeneration of the ovaries to reproduce a second brood. The precursors of these third-year females (a small number the second-year females with an asynchronous [summer] breeding period and ovaries that have atrophied due to seasonal starvation) appear to possess sources of somatic and germ cells that are sufficient for ovarian regeneration and that may be adaptations to starvation stress.