Germ Cell Differentiations During Spermatogenensis and Taxonomic Values of Mature Sperm Morphology of Pinctada martensii (Bivalvia, Pteriomorphia, Pteriidae)

Abstract

The ultrastructural characteristics of germ cells during spermatogenesis and mature sperm morphology in male Pinctada martensii were investigated by transmission electron microscope observation. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately 47-50 μm in length including a sperm nucleus (about 1.24 μm in length), an acrosome (about 0.60 μm in length), and tail flagellum (about 45-47μm). The axoneme of the sperm tail shows a 9+2 structure. In P. martensii in Pteriidae, a special substructure showing a thick and wide triangular shape which is composed of electron-dense opaque material (occupied about 50% of all, the upper part of the acrosomal vesicle), appeared in the upper region (part) of the acrosomal vesicle, while the lower region (part) of the acrosomal vesicle is composed of electron-lucent material. Thus, this special structure, which exist in the upper part of the acrosomal vesicle in P. martensii, is somewhat different from those of other subacrosomal vesicle in other families in subacrosomal vesicles. Therefore, we assume that the existence of a special substructure showing a thick and wide triangular shape in the acrosomal vesicle of the spermatozoon can be used as a key characteristic for identification of P. martensii or other species in Pteriidae in subclass Pteriomorphia. The number of mitochondria in the midpiece of the sperm of this species are five (exceptionally sometimes four), as one of common characteristics appear the same number of mitochondria in the same families of superfamilyies. This species in Pteriidae does not contain the axial rod and satellite fibres which appear in the species in Ostreidae in subclass Pteriomorphia. These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.

Developmental Phases of the Seminal Vesicle related to the Spermatogenic Stages in the Testicular Lobules of Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae)

“…cumingii is very similar to that of other neogastropods with internal fertilization. The acrosome shape of molluscan sperms can be classified into four types (Kim et al, 2010; Kim & Kim, 2011; Kang et al, 2012; Son et al, 2014): cone, cap, elongate-modified cone, and modified cap types. Moreover, sperm nucleus types vary with molluscan species.…”

Reproductive Cycle of Sulf clam, Coecella chinensis (Mesodesmatidae: Bivalvia)

“…지금까지 우리나라에서 산업적으로 유용한 조개류의 생식주 기, 산란기 및 정자의 미세구조에 관해 연구, 보고된 조개류는 굴과의 참굴 (Kim, 2001;Kim et al, 2010a), 바윗굴 (Kim, 2001), 강굴 (Kim, 2001) 이 밝혀져 있고, 고막과의 고막 (Kim, 2001), 새고막 (Kim, 2001;Chung et al, 2011), 피 조개 (Kim, 2001), 홍합과의 홍합 (Kim, 2001;Kim et al, 2010b), 굵은줄격판담치 (Kim, 2001; Kim and Kim, 2011), 키조개과의 키조개 (Kim, 2001;Kang et al, 2012), 가리비과의 큰가리비 (Kim, 2001), 비단가리비 (Kim, 2001), 주문진가리비 (Kim, 2001), 백합과의 백합 (Kim, 2005), 말 백합 (Kim et al, 2009), 바지락 (Chung et al, 1994;Chung et al, 2010b), 가무락 (Chung et al, 1991), 대복 (Park et al, 2003;Chung et al, 2010a), 개량조개과의 개 량조개 (Chung et al, 2007), 동죽 (Chung et al, 1988;Chung and Ryou, 2000) (Chung et al, 1994;Kim, 2005 (Kurashige, 1943;Momoyama and Iwamoto, 1979). 그 러나 일본 동경만 이남에서는 일년에 산란계절이 2번 일어난 다 (Ko, 1957;Tanaka, 1954…”