• Parasites, Hosts and Diseases
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• v.33 no.4
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• pp.281-288
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• 1995

For the two-dimensional observation on the growth and development of CLonorchis sinensis, an image analysis system (IBAS 2000, Kontron, Germany) was used in this study. On 3, 6, 9, 12, 15, 21, 30 and 90 days of infection, 474 worms were collected from rats infected with 50 metacercariae each. The overall recovery rate was 31.6%. The worms grew rapidly in their length and width up to 30 days of infection and then, did slowly to 90 days of infection. However, the growth pattern of body area was not similar to that of body length and width, because the body area increased continuously even after 30 days of infection. With the image analysis system, the sizes of irregular-shaped genital organs were measured easily, which showed sigmoidal growth patterns . The growth rate of genital organs increased rapidly. until 21 days of infection when the uterus was filled with numerous eggs, and then gradually slowed down to 90 days. There was no difference in growth pattern between the anterior and posterior testis. The seminal receptacle , however, showed an abrupt increase in size between 15 to 21 days of infection when it was filled with condensed semen. Therefore, the growth pattern of seminal receptacle might be used as another criteria to estimate the extent of sexual maturation of C. sinensis. From this study, it is suggested that image analysis system is very useful to reveal the growth and development pattern of C. sinensis, especially of their internal organs.

• Journal of Aquaculture
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• v.7 no.4
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• pp.207-223
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• 1994

Induction of triploid cherry salmon, Oncorhynchus ma.sou was performed by the heat shock procedure. The triploids were induced by 15 and 20 min heat shock treatments after 10 min fertilization at $28^{\circ}C$. Incidences of the triploidy were $91.4\%\;and\;89.8\%$, respectively. Nucleus and erythrocyte from the induced triploids larger than those of the diploids in major axis, minor axis, major axis/minor axis, surface area and volume. The chromosome number of diploid was 2n= 66 (17 pairs of metacentrics or submetacentrics, 16 pairs of acrocentrics or telocentrics), and that of triploid was 3n=99. Satellites were observed in the short arm of the largest telocentrics, and these may be useful marker to determine the polyploidization. Diploid have outgrown to triploid, and female have also outgrown to male in the triploid group during the 22 months of observation period after hatching. During the spawning season, 22 to 26 months after hatching, diploid were observed the growth retardation because of their sexual maturation, however the triploid showed continuous growth.

• Korean Journal of Ichthyology
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• v.4 no.1
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• pp.96-104
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• 1992

The electrophoretic analysis, variations of protein and nucleic acid contents with sexual maturation, of the liver tissue of male, and of the muscle tissue of male and female B. pectinirostris(Linnaeus) were investigated. As the result of protein analysis of the liver and muscle tissue of male by the SDS-PAGE electrophoretic analysis, the protein of the liver tissue of male was presented 15.8-101.5kd in molecular weight, and appeared 19 bands in all. The protein bands of the muscle tissues of male and female were almost same, their bands were presented 16.9-116.5kd in molecular weight, and appeared 23 bands in all. And in the liver tissue, the protein contents of the liver tissue of male appeared the maximum in June(the mature stage) and afterwards decreased gradually in July(the spawning stage) and August(the degenerative stage). In the muscle tissues of male and female protein contents were shown the maximum in June, and afterwards decreased gradually, the minimum in July, increased a little in August. The total RNA contents of the liver tissue of male, and their contents of the muscle tissue of male and female appeared the maximum in June(the mature stage), and afterwards decreased gradually in July(the spawning stage) and August(the degenerative stage).

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.245-255
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• 2002

In order to obtain the basic information for seedling production of venus clam, Protothaca jedoensis, the annual reproductive cycle was investigated mainly by histological observation from September 1998 to August 1999. P. jedoensis was dioecious. The gonads are located between the digestive diverticula and muscle tissue of the foot. The ovary was composed of a number of ovarian sacs, and the testis was composed of several testicular tubules. The condition index was reached its maximum (20.0) in February, and then decreased to 11.5 in June. In August, the value was the lowest (9.0) and then increased slowly. Minimum size for the sexual maturation of individuals were 38.4 mm in shell length. One the other hand, the size of mature oocytes was ranged to $50-60\mu{m}$ in diameter and testis-ova was observed in testis of the mature stage. The reproductive cycle of P. jedoensis could be classified into five successive stages: early active (December to February), late active (January to April), ripe (March to July), partially spawned (June to August) and spent/inactive (July to January) stages.

• Development and Reproduction
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• v.4 no.1
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• pp.37-43
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• 2000

Spatiotemporal expression of two isoforms of zonular occludens-1 (ZO-1), tight junctional protein, was examined in mouse testis. By RT-PCR, transcripts encoding two isoforms of ZO-1; ZO-1$\alpha$+ and ZO-1$\alpha$- were detected in testis. Two different forms of ZO-1 antigens with Mr.225 and 2001 KDa were detected in western blot of extract of neonatal to adult testis, coinciding with the result of RT-PCR. The relative amount of ZO-1 $\alpha$- versus 20-1 $\alpha$＋ increased as the mice matured. In immunostaining using the pan antibody which detected both isoforms, ZO-1 was localized in the intercellular spaces in the Sertoli cell - Sertoli cell contacts in periphery of seminiferous tubule as well as Sertoli cell - germ cells contacts within the seminiferous tubule. The expression of ZO-1 was ubiquitous in both junctional area and cytoplasm of seminiferous tubule components. However, more intense signals were found in Sertoli cell junctional areas according to sexual maturation. The changes in the relative amount of both isoforms and spatial distribution of ZO-1 at the periphery of seminiferous tubule might be important for functional appearance of blood testis barrier and spermatogenesis.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.545-552
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• 2017

Increasing concern is being given to the association between risk of cancer and exposure to low-dose bisphenol A (BPA), especially in young-aged population. In this study, we investigated the effects of repeated oral treatment of low to high dose BPA in juvenile Sprague-Dawley rats. Exposing juvenile rats to BPA (0, 0.5, 5, 50, and 250 mg/kg oral gavage) from post-natal day 9 for 90 days resulted in higher food intakes and increased body weights in biphasic dose-effect relationship. Male mammary glands were atrophied at high dose, which coincided with sexual pre-maturation of females. Notably, proliferative changes with altered cell foci and focal inflammation were observed around bile ducts in the liver of all BPA-dosed groups in males, which achieved statistical significance from 0.5 mg/kg (ANOVA, Dunnett's test, p<0.05). Toxicokinetic analysis revealed that systemic exposure to BPA was greater at early age (e.g., 210-fold in $C_{max}$, and 26-fold in AUC at 50 mg/kg in male on day 1 over day 90) and in females (e.g., 4-fold in $C_{max}$ and 1.6-fold in AUC at 50 mg/kg vs. male on day 1), which might have stemmed from either age- or gender-dependent differences in metabolic capacity. These results may serve as evidence for the association between risk of cancer and exposure to low-dose BPA, especially in young children, as well as for varying toxicity of xenobiotics in different age and gender groups.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.1-10
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• 2017

The study was carried out to understand the inhabiting status and biological features of nutria (Myocastor coypus) in the Jeju Island from May, 2013 to August, 2016. Five individuals were captured by traps and two individuals were collected in dead. Of the 7 individuals, those whose bio-information could not be known were excluded to perform autopsy of the rest of them. The results from morphological, cranial and anatomical analyses, it was found that the females achieved sexual maturation but had no breeding experience. An adult male showed similar sizes to those found in the Korean Peninsula. After collecting the 7 individuals in 2013, 1 nutria individual was filmed by the scouting camera in May, 2014 but not captured. The long-term investigation of the research area found no inhibiting individual. It is deemed the nutria was either died of natural death or migrated. In order to establish a proper nutria control, the environmental characteristics of Jeju Island should be considered where indigenous and introduced species coexist in a limited space. Our findings will provide helpful information for understanding biological features of nutria and planning protection program of natural ecosystems of Jeju Island.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.413-431
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• 1992

Gonadal development, fertilization and egg development in the maternal body and reproductive cycle of ovoviviparous rockfish, Sebastes inermis, were investigated histologically. Gonadosomatic index(GSI) of male and female were increased from September and reached maximum values in December. In the male, GSI decreased from January, but in the female maintained high values till February and decreased from March. Hepatosomatic index(HSI) was related to GSI conversely. In both sex, HSI increased from February and reached maximum in August as the gonad were degenerating and resting, and began to decrease from September as gonad were glowing. This ovoviviparous rockfish copulates in December. Fertilization with sperms maintained between ovulated oocytes in the ovary occurs in January mainly. Egg development in the ovarian cavity and discharging of hatched preiarva occurs from January to February. The reproductive cycle includes the successive stages: Growing(September), Mature (October-November), Ripe and Fertilization(Decembr-Janua), Egg development and Discharging of hatched larva(January-February), Degeneration and Resting(February-August). According to the frequency distribution of egg diameter and histological observation, the ovoviviparous rockfish discharged the prelarva at a time in a spawning season. The sexual maturation is first attained at 2 ages. All females and males reaches first maturity at body length of 17.1cm and 15.1cm respectively. The mean number of the embryos increased with the increase of the total length of female.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.312-319
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• 2020

Precocious puberty (PP) is defined as the early development of secondary sexual characteristics (before the ages of 8 years in girls and 9 years in boys). The aim of this study is to identify characteristics of the dental maturity in girls with PP that discriminate them from normal healthy girls. This study included 99 girls aged 6 - 8 years with PP and 99 girls without past medical history of same chronological age (control group). The study was performed on 198 panoramic radiographs (99 PP girls, 99 control group girls). Demirjian method was used to evaluate the panoramic radiographs and determine dental maturity. Difference in dental maturity score and tooth formation stages between the two groups were analyzed. The PP group showed significant higher maturity score than control group. Among mandibular teeth, mandibular 2nd premolar and 2nd molar were significantly more mature in the PP group than control group. Logistic regression analysis showed that mandibular 2nd molar was only significant predictor for PP girls.

• Development and Reproduction
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• v.16 no.2
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• pp.121-128
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• 2012

Kisspeptin has been reported to facilitate sexual maturation and ovulation by directly stimulating GnRH neurons via its receptor, GPR54. The KiSS-GPR54 system is playing an important role in the reproduction of several mammalian species. However, little is known about their function in fish. The aim of this study is to understand the physiological function and evolutionary conservation of KiSS-GPR54 system in teleost fish blacktip grouper, Epinephelus fasciatus. In the present study, we have partial cloned KiSS1, KiSS2 GPR54 mRNAs from a brain samples. Tissue distribution analysis using RT-PCR revealed that the KiSS1, KiSS2, GPR54 transcripts were expressed in different tissue. The KiSS-GPR54 system in gonadal of immature and mature stage were analyzed using qRT-PCR. The partial sequence of KiSS1, KiSS2, GPR54 were 232 bp, 304 bp, 613 bp long, respectively. KiSS1, KiSS2, GPR54 mRNAs are shown common expression in the brain. The amount of KiSS1, KiSS2 mRNAs expression were significantly higher in mature stage than immature stage. However GPR54 mRNA expression was higher in immature stage. These results are in good agreement with the hypothesis that KiSS-GPR54 system plays an important role in the regulation of reproductive function in the blacktip grouper.