• Journal of radiological science and technology
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• v.42 no.6
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• pp.429-434
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• 2019

The gonads are directly affected by radiation exposure during radiography of the pelvis, abdomen, and spine. Exposure of the gonads to radiation can cause genetic mutations and can result in the occurrence of malignant tumors. In this study, we created three types of shielding material shapes for shielding of the ovaries, which are the gonads of female during radiography of the pelvis, and comparative evaluations using shadow shielding methods. The source surface distance(SSD) was 100 cm and the field size was 42 cm × 43 cm. The three types of shielding material shapes(type 1, 2 and 3) were assessed and the entrance surface dose in the ovaries were measured. The thickness of the shielding material was expanded from 0.3 mm to 2.4 mm and after five repetitions, radiation values were measured and mean values were calculated. The mean dose were 3.09 mGy for type 1, 3.54 mGy for type 2, and 3.19 mGy for type 3, indicating that the measurements were the lowest for type 1. When an additional filter of 0.2 Cu + 1 Al was used, the dose were 3.72 mGy for type 1, 5.43 mGy for type 2, and 4.05 mGy for type 3, indicating that the measurements were the lowest for type 1. The results show that, even if the shielding material is not thick, in other words, even with a thickness of 2.94 mGy for the SN 3(0.9 mm) of type 1, shielding can be achieved, with a patient dose lower than the diagnostic reference level(3.42 mGy). Additionally, among the three types of shielding material, the type 1 appeared to be the most appropriate shielding material. It is thought that the use of shielding material could reduce the risk factors for stochastic effects or critical effects of ionizing radiation during pelvic or lumbar radiography.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.781-787
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• 2017

Objective: The early growth response (Egr) family consists of four members (Egr1, Egr2, Egr3, and Egr4) that are zinc finger transcription factors. Among them, Egr3 is involved in transcriptional regulation of target genes during muscle spindle formation and neurite outgrowth. We previously showed that the immunoreactive Egr3 is localized on oocyte spindle and accumulate near the microtubule organizing center during meiosis I in mice. Egr3 was also shown to be localized on spermatocytes. We herein investigated if Egr3 is expressed in mouse gonads and if Egr3 blockade results in any defect in oocyte maturation. Methods: Expression of Egr3 in mouse gonads was examined by reverse transcription-polymerase chain reaction. Full-length Egr3 and truncated Egr3 (${\Delta}Egr3$) complementary RNAs (cRNAs) with Xpress tag at N-terminus and DsRed2 at C-terminus, and small interfering RNA (siRNA) targeting Egr3 were microinjected into mouse oocytes at germinal vesicle stage. Localization of microinjected Egr3 was examined by confocal live imaging and immunofluorescence staining. Results: Egr3 mRNA was detected in mouse ovaries and testes from 1 to 4 week-old mice. An uncharacterized longer transcript containing 5'untranslated region was also detected in 3 and 4 week-old gonads. Microinjected Xpress-Egr3-DsRed2 or Xpress-${\Delta}Egr3$-DsRed2 localized to nuclei and chromosomes during meiotic progression. Microinjection of these cRNAs or Egr3 siRNA in oocytes did not affect meiotic maturation. Immunofluorescence staining of Egr3 in Xpress-${\Delta}Egr3$-DsRed2-injected oocytes showed a positive signal only on meiotic spindle, suggesting that this antibody does not detect endogenous or exogenous Egr3 in mouse oocytes. Conclusion: The results show that Egr3 localizes to chromosomes during meiotic progression and that certain antibodies may not faithfully represent localization of target proteins in oocytes. Egr3 seems to be dispensable during oocyte maturation in mice.

• Korean Journal of Ichthyology
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• v.7 no.1
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• pp.43-55
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• 1995

Based on the reproductive cycle of Rhodeus uyekii, the reproductive control mechanism was examined under the several combinations of photoperiod and temperature regimes at different phases of their reproductive cycle. In early spring, the gonads developed rapidly under the warm temperature condition(above $8^{\circ}C$), regardless of the photoperiod. In late spring or early summer, gonads intensely regressed under the high temperature condition(above $24^{\circ}C$), regardless of the photoperiod. Thus, it is concluded that the spawning period of R. uyekii is initiated by the rising of water temperature in spring and is terminated by the high temperature in early summer. In autumn, the gonadal recrudescence occurs under the conditions of artificial long daylength with warm temperature(15L/9D, $12^{\circ}C{\sim}20^{\circ}C$), whereas the gonads remain in the existing condition under the short daylength. Therefore, in autumn the gonadal recrudescence is prevented by the short daylength although the temperature is still in favorable condition. In bitterling, the responsiveness of the gonads to photoperiod varies clearly with seasons, which was declined during the winter but increased during the autumn. The critical photoperiod for maturation ranges 12~13 hours of light per day. The results indicate that the proper ranges of temperature and photoperiod for gonadal maturation of this species are from $8^{\circ}C$ to $8^{\circ}C$ and from 13L to 15L, respectively.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.66-67
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• 2005

The domestic chicken (Gallus gallus) is an important model for research in developmental biology because its embryonic development occurs in ovo. To examine the mechanism of embryonic germ cell development, we constructed proteome map of gonadal primordial germ cells (gPGC) from chicken embryonic gonads. Embryonic gonads were collected from 500 embryos at 6 day of incubation, and the gPGC were cultured in vitro until colony formed. After 7-10 days in cultured gPGC colonies were separated from gonadal stroma cells (GSCs). Soluble extracts of cultured gPGCs were then fractionated by two-dimensional gel electrophoresis (pH 4-7). A number of protein spots, including those that displayed significant expression levels, were then identified by use of matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and LC-MS/MS. Of the 89 gPGC spots examined, 50 yielded mass spectra that matched avian proteins found in on-line databases. Proteome map of thistype will serve as an important reference for germ cell biology and transgenic research.

• Development and Reproduction
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• v.10 no.4
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• pp.247-254
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• 2006

It is well publicized that the existence of various endocrine disrupting chemicals threatens normal sexual development of many sedentary marine fishes in the coastal areas. However, a suitable marine fish species for efficient monitoring of this threatening has yet to be identified. One of the difficulties in estimating the effect of endocrine disruption in marine fish is the absence of clear distinction between testicular and ovarian structures at the early stages of sex differentiation. In search of a potential test species, we have investigated the microscopic structures of sexually undifferentiated and differentiated gonads and the susceptibility of gonadal differentiation to exogenous sex steroids during the sex differentiation period in a sedentary marine rockfish, Sebastes schlegeli. Male gonads in this species contained dark pigmentation that made them distinct from female gonads. Treatment either with $estradiol-17\;{\beta}(E_2)$ or $17\;{\alpha}-methyltestosterone$ (MT) significantly altered the sex ratios with the complete sex changes or the occurrence of ovotestis that was easily identified by the mixed structure of dimorphic gonads (coexistence of ovarian cavity/primary oocytes and dark pigmentation/seminiferous tubules). Results in this study suggest that S. schlegeli can be developed as a monitoring/test fish species for endocrine disruption in marine fish in the coastal areas.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.416-421
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• 1998

The objective of this study was to investigate the responsiveness of hypophysis and gonads to synthetic GnRH among noncycling Murrah buffalo heifers at 24 months of age. The plasma FSH, LH, estradiol and progesterone levels were measured in blood samples collected at 1 hour before and upto 18th day subsequent to the administration of GnRH ($(200 {\mu}g)$) or saline (2 ml). The pretreatment levels of plasma FSH, LH estradiol and progesterone among GnRH treated heifers (N = 6) were $11.55{\pm}0.57ng/ml$, $0.68{\pm}0.06ng/ml$, $19.84{\pm}0.82pg/ml$ and $0.45{\pm}0.07ng/ml$ respectively. A quick elevation of FSH (p < 0.01) and LH (p < 0.05) within 5 min of GnRH administration was observed in all the heifers. The peak FSH ($74.97{\pm}18.63ng/ml$) and LH ($3.09{\pm}0.54ng/ml$) level was obtained at 30 min of GnRH administration. The elevated level of plasma estradiol on 5th to 18th day, FSH on 7th to 9th day (n = 3) and the progesterone on 13th to 18th day (n = 2) of GnRH injection was obtained. The study indicates that gonads of buffalo heifers at 24 months of age are responsive of GnRH induced gonadotropin release for folliculogenesis and luteal tissue formation

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.739-744
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• 2015

The sexual maturation and spawning time of female ocean sunfish Mola mola in Korean waters were studied by observing the gonads histologically. Specimens were purchased in a fish market in October 2013 and May, June, and October 2014. Nine females (total length 100-250 cm, gonad weight 31-3,470 g) and one male (total length 131 cm, gonad weight 60 g) were studied. Histologically, the ovaries became active in May and spawning began in July and continued until October. In July, mature oocytes and yolk globule stage oocytes were observed; parts of the gonad showed traces of spawning, while others had degenerated and absorbed any oocytes. By October, many oocytes had degenerated and been absorbed. Therefore, the approximate spawning period of ocean sunfish is from July to October based on histological changes in the gonads. The asynchronous oocyte development suggests that the ocean sunfish is a multiple spawner, as reported previously. The catch distribution data suggest that the waters around Jeju Island are a sunfish spawning area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.296-301
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• 2017

We conducted a study to 1) determine the indicators of gonadal maturity in male and female Korean walleye pollock Theragra chalcogramma for the purposes of artificial insemination; 2) establish the RNA/DNA ratio of mature eggs in this species; and 3) monitor the effect of refrigerated storage on egg viability and the motility of sperm collected from dead adult males. During the spawning season, the color of female gonads changed from orange to transparent, and that of male gonads changed from pale orange to milky white. The DNA content and RNA/DNA ratio of mature eggs were maintained without significant changes for approximately 6 h when eggs were preserved at $4^{\circ}C$. Sperm could be obtained from both milt and undiluted semen. Sperm obtained from milt ceased moving on the second day after isolation, while over 60% of sperm obtained from semen showed movement until the 13th day. Seven attempts were made to artificially inseminate mature eggs, of which two resulted in successful fertilization. The successful inseminations produced 94,000 and 5,000 fertilized eggs, respectively. This study shows that artificial insemination of walleye pollock is a viable strategy when natural propagation is not possible.

• Animal cells and systems
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• v.8 no.1
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• pp.33-40
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• 2004

Reproductive cycle and spawning rhythm with lunar cycle of the ascidian, Halocynthia hilgendorfi ritteri were investigated by histological examination. The specimens were sampled in the coastal waters of Yongdam, northwest of Jeju Island, Korea, from November 2001 to January 2003. H. hilgendorfi ritteri is a synchronous hermaphrodite; the gonads are located in the mantle. The reproductive cycle can be grouped into the following successive stages in the ovary: growth (February to June), vitellogenesis (April to September), mature (July to December), spent (November to February), and recovery (December to April). Likewise, in the testis, the stages observed were: growth (October), mature (October to December), spent (November to February), and resting (January to September). Major spawning probably occurs between November and January, when water temperatures decrease. The histological observations of the gonads suggested that this species is a multiple spawner during the spawning period. Spawning occurred between the new moon and full moon, and again between the full moon and new moon, suggesting that the spawning rhythm is influenced by the lunar cycle.

• Development and Reproduction
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• v.10 no.2
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• pp.79-84
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• 2006

We reviewed sex-change patterns in the wrasses Halichoeres poecilopterus, H. tenuispinis, Pteragogus flagellifer, and Pseudolabrus sieboldi inhabiting the coastal waters of Jeju, Korea, based on the sex distribution according to standard length and sex characteristics of the gonads. Halichoeres poecilopterus, H. tenuispinis, Pt. flagellifer, and Ps. sieboldi are protogynous hermaphroditic fish. Histological observations revealed that these wrasses are undelimited type 2 species because testicular tissue(spermatogenesis area) appears in most parts of the gonads during ovary of degenerative stage. Both initial- and terminal-phase males were present in the investigated populations, indicating that Halichoeres poecilopterus, H. tenuispinis, and Ps. sieboldi are of the diandric type. In contrast, Pt. flagellifer is considered a monandric type, because all males in the investigated populations were terminal-phase males produced via sex change from functional females.