Studies on the fine structure of spermatids and spermatozoa of the crab, Pinnixia sp.

Abstract

Early spermatids of the crab, Pinnixia sp., are characterized by a large nuclear/cytoplasmic ratio. During early spermiogenesis an organelle, composed of pentalaminar membranes derived from the endoplasmic reticulum and nuclear membranes, is formed. Portions of this organelle become incorporated within a cylindershaped invagination of the acrosome. Portions of the nuclear membrane disappear beneath the acrosome resulting in intermingling of nucleoplasm, centrioles and mitochondria. The nuclear membrane elsewhere is found as a pentalaminar membrane underlying the plasma membrane. Centrioles are found in mature spermatozoa at the base of the cylinder-shaped acrosomal invagination, and mitochondria are found intermingled with nuclear remnants surrounding the acrosome. This datum is compared to previously described events in spermiogenesis of other decapod crustacea and arthropods exhibiting similar modes of spermiogenesis. It is concluded that the differences and/or similarities exhibited by centrioles and mitochondria in these forms could be significant in terms of subsequent zygote differentiation.Studies on the coalescence of cytoplasmic organelles and nucleoplasm have now been described in spermatozoa of several animals. These studies include the cray- genesis in different arthropods, Assuming that centrioles and/or mitochondria function in subsequent zygote development in these animals, the differences exhibited during spermiogenesis could have important genetic implications due to the absence or presence of these organelles (Granick and Gibor, '67; Nass, '69).The following study on spermatids and spermatozoa of the crab, Pinnixia sp., was made in order to extend such studies to another species of crustacea since datum on at least three of the above crustacea is conflicting. This either implies species differences in behavior of centrioles and mitochondria during spermiogenesis, errors in interpretation of data, or both. Studies on closely related and/or divergent crustacean types should help broaden our concepts about the possible genetic contributions of these organelles in such animals. MATERIALS AND METHODSFollowing ventral orientation of male Pinnixin S P .~ and incision into the ventral abdominal cavity, testes, vas dderens and seminal receptacle were removed and 1 Supported by U.S.P.H.S grant NB-06285.

Spermatogenesis of the spider crab Maja brachydactyla (Decapoda: Brachyura)

“…These events were summarized as follows: 1) cellular polarization caused by the marginalization of the nucleus, along with the development of the proacrosomal vesicle; 2) formation of a ring by the membranous system; 3) development of the operculum and perforatorium in the acrosomal vesicle; 4) nuclear surrounding of the acrosome; and 5) development of the radial arms (Binford, 1913;Fasten, 1918Fasten, , 1926Nath, 1932). Later studies using TEM (Yasuzumi, 1960;Pochon-Masson, 1962, 1968Langreth, 1969;Reger, 1970;Du et al, 1988;Medina and Rodríguez, 1992b;Li, 1995;Wang et al, 1997b;Wang et al, 1999), including the present work, support these findings.…”

“…Because the germ cells within a cross section of the seminiferous tubule were all in the same stage or two successive stages, the differentiation of the germ cells had to be followed along the testis. Our work complements previous ultrastructural studies in brachyurans that were focused on spermiogenesis (Yasuzumi, 1960;Pochon-Masson, 1968;Langreth, 1969;Reger, 1970;Du et al, 1988;Medina and Rodríguez, 1992b;Li, 1995;Wang et al, 1997b;Wang et al, 1999). All previous studies were performed with the higher groups within Eubrachyura, but majids appear in the basal positions within this group, and therefore the results presented here carry potential phylogenetic significance (see Jamieson and Tudge, 2000 for phylogenetic discussion).…”

“…(Langreth, 1969), Pinnixa sp. (Reger, 1970), E. sinensis (Du et al, 1988), Uca tangeri (Medina and Rodríguez, 1992b), Portunus trituberculatus (Li, 1995), Scylla serrata (Wang et al, 1997b), and Sinopotamon yangtsekiense (Wang et al, 1999). Although in some animal species a transverse section of the testis contains most stages of spermatogenesis (Beninger and Pennec, 1991;Patiñ o and Redding, 2000;Sasso-Cerri et al, 2004;Cledón et al, 2005;Thongkukiatkul et al, 2008), in brachyurans, cells belonging to the same transverse section of the testis are usually in the same stage of development (Krol et al, 1992).…”

A transmission electron microscopy investigation: the membrane complex in spermatogenesis of Fenneropenaeus chinensis

“…Membrane complex originated from cytoplasm occurs during the spermiogenesis of F. chinensis, and it is comprised derivative of endoplasmic reticulum, mitochondria and nuclear membrane which is similar to that reported in most species (Langreth 1969;Reger 1970;McKnight and Hinsch 1986;Du et al 1988;Medina 1994;Li 1995;Tudge et al 2001;Zhu et al 2002;Medina et al 2006). The only difference lies in the typical annular lamina bodies wound from the endocytoplasmic reticulum in the membrane complex of F. chinensis.…”

“…The morphology and structures of such sperms vary from species to species, although they all share the same characteristics, such as without flagella, unmovable and without condensed nucleus. In the past, several research groups have studied the morphology of the sperm and spermatiation, including the membrane complex in spermatogenesis (Moses 1961;Kaye et al 1961;Langreth 1969;Reger 1970;Arsenault et al 1979;Arsenault 1984;Haley 1986;Mcknight and Hinsch 1986;Shigekawa and Clark 1986;Du et al 1988;Medina and Rodrfguez 1992;Medina 1994;Li 1995;Yang et al 1998;Wang et el. 1999;Tudge et al 2001;Zhu et al 2002;Medina et el.…”