• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.944-951
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• 2016

Tdrd12 is one of tudor domain containing (Tdrd) family members. However, the expression pattern of Tdrd12 has not been well studied. To compare the expression levels of Tdrd12 in various tissues, real time-polymerase chain reaction was performed using total RNAs from liver, small intestine, heart, brain, kidney, lung, spleen, stomach, uterus, ovary, and testis. Tdrd12 mRNA was highly expressed in testis. Antibody against mouse TDRD12 were generated using amino acid residues SQRPNEKPLRLTEKKDC of TDRD12 to investigate TDRD12 localization in testis. Immunostaining assay shows that TDRD12 is mainly localized at the spermatid in the seminiferous tubules of adult testes. During postnatal development, TDRD12 is differentially expressed. TDRD12 was detected in early spermatocytes at 2 weeks and TDRD12 was localized at acrosome of the round spermatids. TDRD12 expression was not co-localized with TDRD1 which is an important component of piRNA pathway in germ cells. Our results indicate that TDRD12 may play an important role in spermatids and function as a regulator of spermatogenesis in dependent of TDRD1.

• Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.143-149
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• 2007

This study describes spermatogenesis and sperm ultrastructure of the granular ark, Tegillarca granosa using light and electron microscopy. In the active spermatogenic season, the testis comprises many spermatogenic follicles that contain germ cells in different developmental stages. Primary spermatocytes in the pachytene stage are characterized by synaptonemal complexes. The early spermatids are characterized by the appearance of several Golgi bodies, increased karyoplasmic electron density, and tubular mitochondria. The mass of proacrosomal granules consists of numerous heterogeneous granules with high electron density that are about 20 nm in diameter. From the midstage of spermiogenesis, the well-developed mitochondria in the cytoplasm aggregate posterior to the nucleus and surround the proximal and distal centrioles. The proacrosomal granules condense and form a single acrosome with a thin envelope. During late spermiogenesis, the acrosome begins to elongate becoming conical. The sperm is approximately $35.0{\mu}m$ long and consists of a head, midpiece, and tail. The head comprises a round nucleus and a conical acrosome. A micro fibrous axial rod is observed between the nucleus and acrosome. The midpiece has a calyx-like structure with five mitochondria, and the tail, which has the typical "9+2" microtubular system, originates from the distal centriole.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.453-459
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• 2004

Chick embryos from stage 14 to stage 31 were studied by means of serial section and light microscopy in order to learn the relationship between the settlement sites of the primordial germ cells (PGCs) and the forming genital ridge. The results showed that: when embryo hatched for 53-56 h, the PGCs reached the coelomic epithelial tissue where gonad would be formed, meanwhile the epithelial tissue began thicker before the PGCs reached. Before stage 19, the final region the PGCs arrived was the thickened portion of the coelomic epithelium, the glycogen in the PGCs cytoplasm maintenance remained unchanged. However at the 3.5-5th hatching day, the glycogen in the PGCs cytoplasm reduced gradually. On the 6th hatching day, the gonad of the embryo appeared the feature of ovary, and the glycogen in the PGCs cytoplasm reduced further. On the 7th hatching day, the differentiation of ovary or testis was obvious and the glycogen in the PGCs cytoplasm later disappeared.

• Applied Microscopy
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• v.31 no.2
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• pp.143-156
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• 2001

The aim of this study was to clarify the differentiation of seminiferous epithelial cells and spermiogenesis in the testis of Rana catesbeiana. Spermatogenesis of R. catesbeiana consists of primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes and spermatids. They were subdivided into eight stages on the basis of the morphological features of the germ cell differentiation. From the spermatocytes except primary spermatogonia to before the spermiation of spermatids were surrounded by spermatocyst. Spermiogenesis of R. catesbeiana can also be divided into three stages on the basis of morphological features of the nucleus and the cytoplasm organelles. Spermatozoon contained a saccular acrosome, a cylindrical and tapered slighty at both ends head, and a tail with only the axoneme.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.145-152
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• 1998

Many trials have been made to produce transgenic animals using sperm cells as a vector transferring foreign DNA into eggs, but reliable results are yet to be obtained (Brinster et al., 1989; Lavitrano et al., 1989; Bachiller et al., 1991; Sato et al., 1994). Recently, one of author(SO) demonstrated that mouse blastocysts derived from eggs fertilized by spermatozoa of male mice single injected with liposome-DNA complexes within the testis expressed thegene (Ogawa et al., 1995.) Here we report that a single injection of liposome-encapsulated DNAs into the testis of either male rats or mice resulted in successfully gene transfer to the postpartum progeny. The expression of mRNA derived from transgenes was also demonstrated in transgenic animals thus obtained. Further, the transmission of the exogenous gene to the descedants was confirmed in one line of transgenic rat up to F4 generation, indicating that the gene was stably incorporated into the germ line. Thus, direct single injection of foreign DNA into the testis provides a novel and convenient means to generate transgenic animals.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.1-6
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• 2006

Abstract - Global decline in wildlife mammals has been accelerated during past decades. Especially the conservation the wild life mammals in polar areas, is urgent. In an effort to understand the reproduction of the seals dwelling in the polar area, spermatogenesis in the seals was reviewed. Seals breed seasonally and in most of the seal species, delayed implantation is frequently observed. To date, histological and endocrinological evaluation revealed highly cyclic nature in supermatogenesis and steroidogenesis in testis. Seasonal changes in blood testosterone level together with melatonin is closely related with changes in light cycle between summer and winter. In adult testis at breeding seasons, spermatogenesis is manifested by consecutive 18 stages of germ cell development. Three kinds of Leydig cells different in steroidogenic activity as well as cellular morphology appear during the testis development. During non-breeding season, spermatogenic arrest and Leydig cell hypoplasia are frequently found. Interestingly, blood circulation through the anastomoses of pelvic veins cooled the testes and thus guarantees spermatogenesis within the body trunk. Endocrine disruptors and heavy metals have been found in the body tissues of several seals species and alter steroidogenesis in seals, suggesting environmental pollutants together with decrease in habitats are potentially threatening the reproductive success in seal species.

• Development and Reproduction
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• v.3 no.1
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• pp.1-13
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• 1999

It is believed that genetic defects make an important contribution to male infertility. Since spermatogenesis is such a complex process, it seems inevitable that many genes are involved in controlling the entire development of germ cells. Genes for infertility, however, are considered to be only those which are defected in the reproduction ability, but normal in other functions. Microdeletions of the Y chromosome have been observed frequently in infertile males. At least two genes, RBM and DAZ, are known to present in the loci where microdeletions occur frequently. A number of autosomal genes were also considered as candidates of infertility genes, based on phenotypes of knockout mice that were deficient of these genes.

• Korean Journal of Veterinary Research
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• v.26 no.2
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• pp.201-210
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• 1986

The cycle of the seminiferous epithelia in the testis of mature Korean native cattle was divided into twelve stages, using criteria the morphological changes in the acrosomic system and the nuclei of developing spematids and germ cells. The results were summarized as follows; 1. The minimum number of tripe A spermatogonia were the average of 1.8 in both at stages I and VI, while maximum numbers were the average of 4.2 at stage XII. Some type A spermatogonia divided at stage XII to produce the type intermediate(IN) spermatogonia at following stage I. The intermediate type spermatogonia divided at stage IV to produce the type B spermatogonia at stage V. 2. The type B spermatogonia divided at stage VII to produce the preleptotene primary spermatocytes at stage XII. The pachytene primary spermatocytes divided at stage XI to produce the secondary spermatocytes at stage VII. The secondary spermatocytes observed at stag XII divided to give rise to the round spermatids at following stage I. Each numbers of the first spermatocytes and of spermatids were almost constant, respectively, through the cycle of the seminiferous epitherium. 3. The relative frequencies of each stage among stages I to XII of the cycle of the seminiferous epithelia were 6.1, 3.7, 5.2, 7.8, 2.2. 3.3, 13.8, 18.4, 11.8, 7.2, 18.1% and 2.4%, respectively.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.137-144
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• 2010

To evaluate the biohazard properties of an extremely low frequency electromagnetic field (ELF-EMF), we explored the physical properties of the ELF-EMF that generates the electric current induction in the secondary coil from the chamber of a primary solenoid coil. We subsequently explored the biological effects of a strong alternating electromagnetic field (EMF), ranging from 730-960 Gauss, on the mouse testis. Mice were exposed to an alternating EMF field induced by a rectangular electric current at 1, 7, 20, 40, and 80 Hertz, for 1, 3, 5, and 7 hours. The mouse testes were examined for proliferative activity and apoptosis using the in situ terminal deoxynucleotidyl transferase (TdT) method and by immunostaining of proliferating cell nuclear antigen (PCNA), respectively. We found that the electric currentm induction increased in the 6-8 Hertz range, and that exposure to an ELF-EMF induced the apoptosis of mouse spermatocytes. In situ TdT staining was found to be most prominent in 7 Hertz group, and gradually reduced in the 20, 40, and 80 Hertz groups. These data suggest that a strong EMF can induce reproductive cell death within a short time, and the harmful effects of the EMF are maximal at low frequency alternating EMFs.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.115-124
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• 2006

Gonad index, spermatogenesis and the reproductive cycle of Meretrix petechialis were investigated by cytological, histological observations. Monthly changes in the gonad index coincides the gonadal development. The morphology of the spermatozoon had a primitive type and is similar to that of other bivalves having a short mid-piece with five to six mitochondria surrounding the centrioles. The morphology of the sperm nucleus type and the acrosome shape of this species were cylindrical type and cap-like shape, respectively. The spermatozoon was approximately 40-45 ${\mu}m$ in length including the sperm nucleus length (about 1.50 ${\mu}m$), acrosome length (0.60 ${\mu}m$) and tail flagellum. The axoneme of the tail flagellum consisted of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail showed 9 + 2 microtubular arrangement. The spawning period was from June to September and the main spawning occurred from July to August when seawater temperatures were higher than $20^{\circ}C$. The reproductive cycle of this species could be categorized into five successive stages: early active stage (February to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to September), and spent/inactive stage (September to February).