Ultrastructure of ovotestis of young and adult pulmonate mollusk, Macrochlamys indica Benson, 1832

Abstract

Macrochlamys indica is a hermaphrodite terrestrial pulmonate mollusk. Transmission electron microscope studies were done on the ovotestis of young and adult (older) M. indica which are elaborated in this paper.The ovotestis contains numerous lobes each of which contains many ovoid shaped acini which are occupied by stages of spermatogenesis and a single oocyte. In younger snails, the acini contain stages of developing spermatogenesis, whereas each acinus of older snails is composed of single large oocyte and few stags of spermatogenesis. The number of Sertoli cells is high in the acini of younger snails than in older snails. Details of the cellular organization of the Sertoli cell are described. Some long thin threads extend from the acinar boundary to acinar lumen. The anterior end of these threads is either free or directly connected to the developing cells of spermatogenesis. There are two types of cells in the interacinar space of the ovotestis in both younger and older snails. One cell is small oval interstitial cell and other is thin elongated periacinar cell. The acinar boundary contains secretory cells with deeply stained nucleus. In the acinus of older snails, the Sertoli cells do not form any barrier between oocyte and spermatogenic cells.Functions of the periacinar cell and interacinar cell are discussed. It is found that the spermatogenesis is highly active in younger snails with single dormant oocyte while process of oogenesis predominates in the older snails. The reproductive strategy of this pulmonate species thus depends on the individual's body size and their maturity.

Ovotestis Isolation and Cryopreservation of Nesiohelix samarangae (Oriental Snail) as a Snail Model for Conserving Other Endangered Snail Species

“…However, in the ovotestis of both L. fulica and N. samarangae, the presence of eggs was not observed. In younger individuals, the predominant process may be the formation of sperm [2]. Although we detected the presence of spermatids in the ovotestis of N. samarangae, we were unable to observe the final stage of sperm.…”

“…Nesiohelix samarangae (the oriental snail) is a terrestrial snail belonging to the phylum Mollusca, class Gastropoda, order Pulmonata, superfamily Stylommatophora, and family Bradybaenidae [1]. The reproductive organs of N. samarangae are simultaneous hermaphrodites or ovotestes, where both male germ cells, such as spermatogenic cells, and female germ cells, such as ova, coexist simultaneously [2]. Snails consume leaves and small plants, and as they move through the soil, they excrete waste, which enriches the soil with nutrients [3].…”

“…Research on using cryopreservation of reproductive organs for species conservation has been actively conducted in endangered amphibians [11], fishes [12,13], and mammals [14], while studies on snails have been relatively scarce. Research in snail reproductive biology has been conducted on the maturation of oocytes in the ovotestis of the African giant snail (Achatina fulica) [15,16] and the microstructure of the ovotestis of Macrochlamys indica [2].…”

Yolk proteins of the schistosomiasis vector snail Biomphalaria glabrata revealed by multi-omics analysis

“…The ovotestis comprises sack-like acini within which male and female gametes develop. Each acinus contains various developmental stages of female and male gametes and 8–9 types of supporting or accessory cells, such as follicle cells and sertoli cells 6 , 30 , 53 , 54 . Isolation of a particular type of cells, like oocytes and follicle cells, from the ovotestis for molecular studies has remained a significant challenge.…”

Effects of the shed skin aqueous extract of the non-poisonous snake, Ptyas mucosus (Linnaeus, 1758) on the development of the ovotestis of Onchidium tigrinum (Stoliczka 1869) (Systellommatophora: Eupulmonata: Gastropoda)

“…Like other pulmonates (Luchtel 1972a, b;Jong-Brink et al 1981;Norton et al 2008;Ping 2008), the gonad of the O. tigrinum is ovotestis and composed of numerous ovoid-shaped acini (Roy et al 2018). In pulmonates, both the male and female gametes are developed in each ovotestis acinus with some somatic barrier (Jong-Brink et al 1976;Eckelbarger and Eckelbarger 1989;Rakshit et al 2005;Bing et al 2008;Roy et al 2016;Roy eta l. 2018;Roy et al 2019). The body weight of the O. tigrinum is directly correlated to the gender choice as well as the predominancy of either the spermatogenesis or oogenesis in their ovotestis acini (Roy et al 2018) and these are resembled with the other pulmonates (Tomiyama 1996;Michiels et al 2003;Koene et al 2007;Bing 2008;Norton et al 2008;Hermann et al 2009;Janssen and Baur 2015;Roy et al 2016).…”