• Animal cells and systems
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• v.5 no.4
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• pp.327-331
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• 2001

There is a critical developmental period during which brain sexual differentiation proceeds irreversibly under the influence of gonadal hormone. Recently, kinesin superfamily-associated protein 3 (KAP3) gene expressed during the 'critical period' of rat brain differentiation was identified by us (Choi and Lee, 1999). KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons (Yamazaki et al., 1996). mRNA level of KAP3 gene markedly increased before the initiation of puberty. Neonatal treatment of estrogen clearly inhibited the prepubertal increase in KAP3 mRNA level (Choi and Lee, 1999). In the present study, we aimed to investigate the effects of polychlorinated biphenyls (PCBs), as endocrine disruptors (EDs) on the expression of KAP3 gene during the 'critical period' of rat brain development. In our data, PCBs significantly decreased the expression of KAP3 gene in the fetal (day 17) and the neonatal (day 6 after birth in) male and female rat brains. The body weight and the breeding ability were significantly decreased in the PCBs-exposed rats compared with the control. These results showed that PCBs affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the fetal and the neonatal rat brains. The maternal exposure to the PCBs may lead to toxic response in embryonic brain sexual differentiation and breeding ability after sexual maturation. This study indicates that KAP3 gene may be useful as a gene marker to analyze the molecular mechanism of toxic response in the animal brain development and sexual maturation exposed to PCBs.

• Journal of Oral Medicine and Pain
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• v.8 no.1
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• pp.121-126
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• 1983

This study is conducted with a view to make correct sexual differentiation by the utilization of discriminant functions. For that purpose were randomly sampled out 148 young adults testes, comprising 67 males and 81 females, ranging from 15 through 18 years fo age. Based on the values made available from the measurement of 6 items corresponding to the maxillary cast models, a statistical analysis was made to abstract feasible discriminant functions. The results findings are as follows: 1. The mean value by sex indicates, in all items, higher one in male group than in female group. 2. Through the measurement were defined as singnificant items in sexual differentiation the bucco-lingual dimensions of canine, 1st-molar, 2nd molar, and 1st bimolat width. 3. Derived from the value from measurement items were discriminant functions with the intention of applying them to sexual differentiation, as follows: 1) Y=-25.4112+0.7513BL3+0.3298BL4-0.2854BL5+0.7350BL6-0.3482BL7+0.2893AW (as tested by Method I) 2)Y=-25.0628+0.7737BL3+0.7468BL6-0.3885BL5+0.2951AW(as tested by Method II) BL3 : Bucco-lingual dimension of upper canine BL4 : Bucco-lingual dimension of upper first prmolar BL5 : Bucco-lingual dimension of upper second premolar BL5 : Bucco-lingual dimension of upper first molar BL6 : Bucco-lingual dimension of upper second molar AW : Upper first bimolar width 4. Sexual defferentiation in terms of descriminant functions represented a probility of 74.6%.

• Journal of Life Science
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• v.6 no.3
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• pp.165-170
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• 1996

The action of phospholipid on the rhodotorucine A(RH.A) acceptance by heterbasidiomyceteous yeast Rhodosporidium toruloides mating type a cells and the effect of medium composition during sexual differentiation were investigated. Activation of trigger peptidase(TPase)was very sensitive to the originated phospholipid from R. toruloides and was more sensitive to phospholipid liposome made up of phospholipi. Phospholopod present on the membrance of mating type a cells consists of phospatidylglycerol(PG), phosphatidylethanolamine(PE), phospatidylcholine(PC), phospatidylinositol(PI), and phosphatidylserine(PS) of 12.9, suprisingly 45.4, 11.0, and 13.9%, respectively. As the result of using C-1 and N-1 mediums which limited C and N sources capable of inhibiting the synthesis of phospholipid, it resulted inhibiting sexual dlfferentiation and production of Rh.A from mating type Acells.

• 대한생식의학회:학술대회논문집
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• 2007.06a
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• pp.19-37
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• 2007

• Development and Reproduction
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• v.4 no.1
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• pp.95-100
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• 2000

A large number of man-made chemicals that have been released into the environment have the potential to disrupt the endocrine system of animals and humans. There is a critical developmental period during which sexual brain differentiation proceeds irreversibly under the influence of gonadal hormone. Recently we identified KAP3 gene expressed during the critical period of rat brain sexual differentiation. KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons. In the present study, we aimed to investigate the effect of endocrine disrupter, Dichlorodiphenyl trichloroethane (DDT), on the KAP3 gene expression during critical period of rat brain development. Maternal exposure to DDT increased the level of KAP3 mRNA in male and female fetus brains when examined on the gestational day 17 (GDl7). In postnatal day 6, DDT suppressed the expression of KAP3 gene in male and female rat brain. Also, the body weight and fertilization rate were decreased in the DDT exposured rats. These results showed that endocrine disrupter, DDT, can affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the prenatal and the neonatal rat brain and that maternal exposure to endocrine disruptors may lead to a toxic response in embryonic differentiation of brain. And so KAP3 gene may be used a gene maker to analyse the molecular mechanism for toxic response in animal nerve tissues exposed to endocrine disruptors.

• Ocean and Polar Research
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• v.30 no.4
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• pp.401-406
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• 2008

Early gonadal development and sexual differentiation of dark-banded rockfish (Sebastes inermis Cuvier) were followed from parturition to 400 days post parturition (dpp). During this period, average total length (TL) increased from 0.57 to 13.18 cm. Primordial germ cells (PGCs) were first detected at 0.68 cm TL (10 dpp). When fish reached 1.52 cm TL (50 dpp), initial stages of ovarian differentiation were identified by the presence of PGCs containing condensed chromatin and their transformation into meiotic oocytes. At 10.23 cm TL (300 dpp), the ovaries gradually developed into oocytes in the primary yolk stages. Ovary growth was rapid after sex differentiation, but testis tissue continued to multiply without growing until fish reached 6.97 cm TL (200 dpp), after which the production of spermatocytes, spermatogonia, and cyst cells was apparent. Histological analysis of gonadal structure suggested a gonochoristic sexual development pathway. Our analysis of the sex ratio at 400 dpp showed a significantly higher proportion of males.

• Mycobiology
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• v.37 no.3
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• pp.171-182
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• 2009

Many aspergilli that belongs to ascomycetes have sexuality. In a homothallic or self-fertile fungus, a number of fruiting bodies or cleistothecia are formed in a thallus grown from a single haploid conidia or ascospores. Genome-sequencing project revealed that two mating genes (MAT) encoding the regulatory proteins that are necessary for controlling partner recognition in heterothallic fungi were conserved in most aspergilli. The MAT gene products in some self-fertile species were not required for recognition of mating partner at pheromone-signaling stage but required at later stages of sexual development. Various environmental factors such as nutritional status, culture conditions and several stresses, influence the decision or progression of sexual reproduction. A large number of genes are expected to be involved in sexual development of Emericella nidulans (anamorph: Aspergillus nidulans), a genetic and biological model organism in aspergilli. The sexual development process can be grouped into several development stages, including the decision of sexual reproductive cycle, mating process, growth of fruiting body, karyogamy followed by meiosis, and sporulation process. Complicated regulatory networks, such as signal transduction pathways and gene expression controls, may work in each stage and stage-to-stage linkages. In this review, the components joining in the regulatory pathways of sexual development, although they constitute only a small part of the whole regulatory networks, are briefly mentioned. Some of them control sexual development positively and some do negatively. Regarding the difficulties for studying sexual differentiation compare to asexual one, recent progresses in molecular genetics of E. nidulans enlarge the boundaries of understanding sexual development in the non-fertile species as well as in fertile fungi.

• Journal of Animal Science and Technology
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• v.48 no.5
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• pp.651-662
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• 2006

Phthalate esters that are used as plasticizers and also found at low levels in foods such as dairy products are often mentioned as suspected endocrine disrupters. The purpose of the present study is to elucidate whether perinatal exposure to di-n-butyl phthalate(DBP), diisononyl phthalate (DINP) and di-2-ethylhexyl adipate (DEHA) affects several aspects of reproductive function in rats especially sexual differentiation of the brain. To this end, the dams were provided with pulverized soy-free diet containing 20, 200, 2,000 and 10,000 ppm of DBP, 40, 400, 4,000 and 20,000 ppm of DINP, or 480, 2,400 and 12,000 ppm of DEHA from gestational day (GD) 15 to postnatal day (PDN) 21, the day of weaning, and serum sex steroid hormone, gonadotropin levels and sexual behaviors after maturation were assessed. At Postnatal week (PNW) 20-21, serum levels of sex steroids and gonadotropins in both male and female rats, as well as estrous cyclicity in females, were not changed by perinatal exposure to DBP, DINP and DEHA, indicating that these chemicals did not affect sexual differentiation of the brain controlling the endocrine system of hypothalamo-pituitary-gonadal (HPG) axis. On the other hand, inhibitory influences on sexual behaviors, especially on ejaculation in males and lordosis in females, were observed by perinatal exposure to these chemicals. These results suggest that these chemicals may act directly on discrete regions of the hypothalamus regulating sexual behaviors, but not regulating gonadotropin secretion, thereby affect sexual differentiation of the brain with a resultant decrease in sex-specific behaviors in adulthood.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.275-280
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• 1999

Male sexual differentiation involves a cascade of events initiated by the presence on the Y chromosome of the of the SRY (sex determining region of Y chromosome) gene, which causes the indifferent gonad to develop into a testis. Hormonal products of the testis, predominantly testosterone and Mullerian inhibiting subtance (MIS), then control the sexual differentiation of the developing fetus. SRY is a transcription factor; however, target genes for its action have yet to be identified, because the DNA recognition sequence for SRY is found in many genes. Therefore the study of intersex disorders is being used to identify other genes active in the pathway of sexual differentiation. Patients with 46,XY gonadal dysgenesis, or Swyer's syndrome, have streak gonads, normal stature, and a sexually infantile phenotype with Mullerian structures present. The inheritance is usually sporadic but can be autosomal dominant or X-linked recessive. Unlike 45,X patients, stigmata of Turner syndrome are rare. As many as 20 to 30% of patients are at risk for malignant gonadal tumor formation and should undergo gonadectomy soon after the diagnosis is made. We have experienced a case of Swyer syndrome which showed a positive SRY gene in peripheral blood and gonad. So we report this case with a brief review of literatures.

• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.248-253
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• 2001

An histological study was conducted to determine the initial treatment time and treatment duration in the use of sex-reversal hormones in relation to gonadal development and sexual differentiation in the bagrid catfish, Leiocassis ussuriensis. The primordial germ cell, which could be recognized from one-day-old fry, began to protrude into the peritoneal cavity between the mesonephric duct and the gut. The primordial gonad with a genital ridge was developed at 5~10 days after hatching. Sex differentiation of the ovary was identified by the ovarian cavity and meiotic oocytes from 20-day-old larvae. Testicular differentiation was also identified by spermatogonial cells from 20-day-old larvae. It may therefore be concluded that this species belongs to the differentiated type of gonochoristic teleost.