The Cycle of the Seminiferous Epithelium in the Greater Japanese Shrew Mole, Urotrichus talpoides.

Abstract

ABSTRACT. Spermatogenesis and acrosomal formation in the greater Japanese shrew mole, Urotrichus talpoides, were studied by light microscopy. On the basis of acrosomal changes, morphology of spermatid head, nuclear shape, appearance of meiotic figures, location of spermatid and period of spermiation, the cycle of the seminiferous epithelium was classified into 12 stages, and developing spermatids could be divided into 15 steps. The mean relative frequencies of stages from I to XII were 10. 9, 8.7, 9.8, 7.3, 8.5, 10.3, 12.5, 8.7, 5.8, 5.4, 5.1 and 7.1%, respectively. Similar to the case in the musk shrew, the spermatid nucleus of the greater Japanese shrew mole remained in the middle region of the seminiferous epithelium and only the acrosome extended towards the basement membrane. The elongation of the acrosome, however, was not prominent. The proacrosomal vesicle first appeared in stage II and then one large and round granule was seen in stage III. The acrosomal vesicle became flattened on the surface of the nucleus in stage IV. Spreading of the acrosomic system has been recognized from stage VII. In stage VII, spermiation occurred. In stage IX, the spermatid nucleus began to elongate. Elongation and condensation of the nucleus were clearly observed in stage X. In stage XII, pachytene spermatocytes divided into diplotene spermatocytes. In stage XII, meiotic figures and secondary spermatocytes were observed. KEY WORDS: cycle of the seminiferous epithelium, greater Japanese shrew mole, insectivore, spermatogenesis, spermiation.

Effects of Trichostatin A, a Histone Deacetylase Inhibitor, on Mouse Gonadal Development In Vitro

“…Each explant was fixed in Bouin's solution, dehydrated in a graded series of ethanol, cleaned in xylene, and embedded in paraffin wax; then sectioned at 4 µm, stained with periodic acid Schiff (PAS)-hematoxylin [16], and observed by light microscopy. Some sections were subjected to immunohistochemistry as described below.…”

Seminiferous Epithelium Cycle and Developmental Stages of Spermatids in the Clethrionomys rufocanus

“…Comparing type In spermatogonia appearance, the Japanese shrew mole, Urotrichus talpoides (Mizukami et al, 2001) had it in stage I and Clethrionomys rufocanus showed it in stage II, which is faster than other rodents (Table 2). …”

“…The Crocidura shantungensis (Jeong & Lee, 2005) had 14 stages and Suncus murinus (Kurohmaru et al, 1994) had 13 stages. Crocidura watasei (Adachi et al, 1992), Phodopus sungorus sungorus (van Haaster & de Rooij, 1993), Urotrichus talpoides (Mizukami et al, 2001), Meriones unguiculatus (Segatelli et al, 2002), Tamias sibiricus (Jung & Lee, 2004) and Crocidura dsinezumi (Jeong & Lee, 2006) had 12 stages. Didelphis azarae (Orisi & Ferreira, 1978) and Apodemus agrarius coreae (Lee, 2007) had 10 stages.…”

“…Conversely, research on the seminiferous epithelium cycle in mammals such as opossum, Didelphis azarae (Orisi & Ferreira, 1978; Worawittayawong et al, 2005), Watase's shrew, Crocidura watasei (Adachi et al, 1992), Djungarian hamster, Phodophus sungorus sungorus (van Haaster & de Rooij, 1993), Musk shrew, Suncus murinus (Kurohmaru et al, 1994), Japanese shrew mole, Urotrichus talpoides (Mizukami et al, 2001), Mongilian gerbil, Meriones unguiculatus (Segatelli et al, 2002), Korean squirrel, Tamias sibiricus (Jung & Lee, 2004), Crocidura shantungensis (Jeong & Lee, 2005), Crocidura dsinezumi (Jeong & Lee, 2006), Apodemus agrarius coreae (Lee, 2007), Apodemus speciosus peninsulae (Kim & Lee, 2009) were previously widely done, but Clethrionomys rufocanus research has not been reported yet. Thus, this study examines the stages of Clethrionomys rufocanus spermatogenesis and investigates its difference with other rodents.…”

Frequency of stages of the seminiferous cycle in the thick-tailed bush baby (Otolemur garnetti), a prosimian primate: possible phylogenetic implications?

“…There is further spread of the acrosomal cap (arrows) of round spermatids to cover about one-fifth of the nuclear envelope. A type A spermatogonia; P pachytene spermatocyte b seminiferous epithelium with a concomitant acrosomal elongation towards the base of the tubule in shrew moles is an important phylogenetic characteristic of members of the Order Insectivora (Muzukami et al 2001). Consequently, the similarities in spermatogenesis between the thick-tailed bush baby and the two rodents (rat and hamster) and monkey appears to suggest that the bush baby shares a close phylogenetic relationship with the latter three mammalian species.…”