• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2002년도 전기 제14차 학술대회 논문집
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• pp.22-23
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• 2002

• 한국패류학회지
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• 제24권1호
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• pp.1-10
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• 2008

Spermatogenesis and the reproductive cycle in male Spisula sachalinensis were investigated by cytological and histological observations. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves in that it contains a short midpiece with four mitochondria surrounding the centrioles. But spermatozoon of this species has not axial rod and satellite body in the midpiece. The morphologies of the sperm nucleus type and the acrosome shape of this species have a globe-shape type and modified cap-like shape, respectively. The spermatozoon is approximately $40-45{\mu}m$ in length including the sperm nucleus length (about $1.35{\mu}m$), acrosome length (about $1.50{\mu}m$) and tail flagellum. The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9+2 structure. The spawning period of these species lasts from June to July, and the main spawning occurs in July when seawater temperatures are greater than $20^{\circ}C$. The male reproductive cycle of this species can be categorized into five successive stages: early active stage (October to January), late active stage (February to April), ripe stage (April to June), partially spawned stage (June and July), and spent/inactive stage (August to September).

• Clinical and Experimental Reproductive Medicine
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• 제48권4호
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• pp.316-321
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• 2021

Objective: Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification. Methods: Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups. Results: The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect. Conclusion: LC and NAC are promising as potential additives in sperm cryopreservation.

• 한국발생생물학회지:발생과생식
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• 제23권3호
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• pp.255-262
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• 2019

Previously, we reported negative effects of low-dose nonylphenol (NP) exposure on the reproductive organs of F1 male mice. In the present study was further investigated the endocrine disrupting effect of NP exposure to F2 generation male mice. Mice were divided into 2 groups; (1) CON, control animals and (2) NP-50 ($50{\mu}g/L$), animals were treated with NP via drinking water. NP exposures were continuously conducted from parental pre-mating period until the postnatal day (PND) 55 of F2 offsprings. Mice were sacrificed on PND 55 and the reproductive tissue weights were measured. The initial (at PND 21) and terminal (PND 55) body weights of the NP-50 group animals were not significantly different from those of control group animals. NP exposure fail to induce a significant weight change of the testes, seminal vesicle and prostate except absolute epididymal weight (p<0.05). However, pathohistological studies revealed that NP-treated F2 animals showed evident decrease in seminiferous tubule diameters, reduced luminal area and number of germ cells. Also, sloughing morphologies in the tubules were notable. In the caudal epididymis, fewer mature sperms and swollen epithelial cells were found in the NP-treated group. The present study demonstrated that the subchronic low-dose NP exposure induced pathohistological abnormalities in testis and epididymis of F2 mice, and we assumed that these 'qualitative' changes in reproductive tissues could be derived from the epigenetic modifications such as DNA methylation, histone modification, altered DNA accessibility and chromatin structure. Further studies are needed to achieve a better understanding on the multi- or trans-generational effects of NP on the reproductive health and a human application.

• 한국학교보건학회지
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• 제3권1호
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• pp.119-134
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• 1990

The purpose of this study is to find out the need for sex education of middle school students and their parents. For the data collection, the survey was conducted during the period from September 10 to September 20, 1989 by using prepared questionnaire. A questionnaire was given to 592 students of 1st, 2nd and 3rd grade from four middle schools and to 408 their parents in Suwon City. The major results are summarized as follow; 1. Among the 25 questions were asked about knowledge of sex, the structure of reproductive organs, physical change during puberty, menstruation, Sexually stimulation and family plan were answered correctly by over 50% of the students. The higher the grade, the more the knowledge of sex. There was no significant difference between this knowledge and with eider sister or brother. Among the 20 questions were asked about knowledge of sex, sexually stimulation, pregnancy, emission, induced abortion and sexually transmitted disease were answered correctly by over 50% of the parents. 2. 30 questions were asked about attitude of sex, 47.7% of the students and 53.4% of the parents answered 'positive'. There was no significant difference between grade and sex of students. A significant difference '.vas not also found between years and education level of parents. 3. In case of students, experience of sex education was showed the structure of reproductive organs, physical change during puberty, temper during puberty, menstruation, emission more. In the event of parents, experience of sex education was showed the structure of reproductive organs, temper during puberty, menstruation, emission, relationship with apposite sex more. Most students felt that sex education should begin from the first grade of middle school and the first grade of high school strongly. In parents was showed the need for sex education from the primary school and the first grade of middle school highly. Namely, students and parents felt that sex education should begin from puberty. To help good developments and growth of middle school students with rapid change should be educated sex eduction properly for the occasion.

• ALGAE
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• 제23권2호
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• pp.141-150
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• 2008

Populations of Codium amplivesiculatum were found in association with rhodolith beds. We present population trends of C. amplivesiculatum from surveys conducted in the southwestern Gulf of California based on monthly sampling from June 1999 to August 2000. Surveys were conducted at 2 sites in the San Lorenzo Channel at depths of 8 - 12 m. The parameters measured were percent cover, biomass and structure in relation to size of the thalli. From each thallus the following measurements were taken: length and diameter, proportion of each thallus with reproductive structures and the degree of fragmentation (measured as number of small thalli). Mean biomass and cover varied seasonally with the maximum (1036.6 gm$^{-2}$ and 100% cover) present in June 2000 and the minimum in winter (0 gm$^{-2}$ and 0% cover). The longest fronds (3 m) occurred during July 1999 and August 2000, while the maximum diameters of 1.0 cm were present during October and November 1999. There were no significant linear relationships between length and diameter of the fronds, suggesting independent growth. Reproductive structures were common in June and July 1999 with monoic and dioic thalli present. Most fronds were monoic, and this is the first record of this feature for this species. Fragmentation occurred in September, and may be associated with stress from early gametangial reproduction and the combination of high temperatures and low nutrients. A hypothetical life cycle for the species is presented.

• Environmental Analysis Health and Toxicology
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• 제21권1호
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• pp.35-43
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• 2006

Reproduction and organ structure of the pale chub, Zacco platypus in Isa stream were investigated by means of histological methods. The results of the study confirmed reproductive abnormality and histopathological features in the pale chub. The gonadosomatic index (GSI) of the fish showed two peak in April and August. In summer season, GSI of the male was about two times of the female's GSI. Monthly variation of the gonadal development was very irregular. From the histological analysis of the organ structure, epidermal atrophy, necrosis and hyperplasia of pigment cell were observed in the skin. Epithelial layer lifting and clubbing of the lamella and bifurcation of the filament were observed in the gill. Also histological changes as congestion, cytoplasmic degeneration of hepatic cell, degeneration of bile duct, glomerular dilatation, degeneration of renal tubule and pycnosis of interstitial cell were identified in the liver and kidney, respectively.

• Clinical and Experimental Reproductive Medicine
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• 제38권2호
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• pp.82-86
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• 2011

Objective: To evaluate sperm nuclear DNA fragmentation and chromatin structure after 18 hours' incubation at room temperature. Methods: Twenty-eight male partners who participating IVF treatment were prospectively included in this study. Ejaculated sperm count and motility were assessed. The sperm was then immediately processed by the conventional swim-up method. After utilization of some of the sample for routine clinical use, the remainder of each of the samples was divided into two aliquots. One aliquot was immediately assessed for sperm nuclear DNA fragmentation (TUNEL assay) and chromatin structure (toluidine blue [TB] staining). The other aliquot was incubated at room temperature for 18 hours and then assessed by two methods. Only dark-TB sperms were considered as having abnormal chromatin structure. Data before and after extended incubation were compared using a paired Student's $t$-test. Results: Before and after extended culture, nuclear DNA fragmentation assessed by TUNEL was $4.9{\pm}4.7%$ and $7.0{\pm}6.4%$, respectively ($p$=0.008). The proportion of abnormal chromatin structure (dark-TB sperm) was $8.2{\pm}5.6%$ and $10.3{\pm}6.5%$ ($p$ <0.001), before and after incubation, respectively. Conclusion: After 18 hours' incubation at room temperature, sperm nuclear DNA and chromatin structure were significantly affected. The IVF practitioner should bear this information in mind when performing delayed insemination, especially for $in$ $vitro$ maturation cycles.

• 한국환경복원기술학회지
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• 제15권5호
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• pp.155-163
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• 2012

This study was carried out to monitor reproductive responses of great tits in 17 urban forests in Daegu metropolitan city. The reproductive perspectives of great tits were surveyed by using 106 artificial bird nests, of which five or seven nests were set up in every urban forest. A ratio of artificial nests used by great tits for their reproduction was 27.4%. It was showing that forests, where the reproductive response was higher, was located at the edge of the city, or was known as having a good vegetation structure in the urban area. The laying date of a great tit was a little earlier in forests in the middle of the city. It might be dependent on the density of artificial land uses including a residential area and an industrial complex, which are able to increase an urban micro-temperature. Otherwise, natural forests or forest patches nearby natural forests located at the edge of the city were showing that the laying date of great tits was relatively later than the oneee in the forest in the middle of the city. There was a big difference of reproduction perspectives of great tit between the 1st and 2nd reproduction. In the 1st reproduction, a clutch size was larger, while an egg volume was so low. Otherwise, the clutch size was shown so smaller in the 2nd reproduction than in the 1st reproduction, while the egg volume was larger in the 2nd reproduction. It might be due to the survival strategy of a great tit to prepare the winter season for a juvenile. Many variables, regarding to the problem of climate changes, have been linked to the environment of urban area and the bird habitats. Finally, Monitoring a bird reproduction is a valuable work for managing an urban forest as well as for conserving a natural forest.

• 한국어류학회지
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• 제12권3호
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• pp.192-202
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• 2000

주둥치의 암 수 성비는 1.81 : 1로 암컷의 비율이 높게 나타났다. 난모세포 발달양식은 난군동기발달형에 속하며, 정소 조직상은 정원세포 국재형에 속한다. 암 수 모두 첫 번째 군 성숙에 도달하는 크기는 전장 7.5 cm로 조사되었다. 암컷의 생식소중량지수(GSI)는 7월에 12.83으로 가장 높았고, 9월에는 1.08로 가장 낮았다. 수컷의 GSI는 6월에 19.0으로 가장 높았고, 10월에 0.24로 가장 낮았다. 암컷의 간중량지수(HSI)는 GSI와 같은 경향의 변화를 보였다. 가슴반점지수(TSI)는 생식소의 성숙 및 완숙시기인 5월부터 7월 사이에는 낮은 값을 보였다. 암컷의 생식주기는 성장기 (3~5월), 성숙기(5~6월), 완숙 및 산란기 (6~8월), 회복기 (8~11월) 그리고 휴지기 (11~3월)로 구분할 수 있었다. 수컷의 생식주기는 분열증식 및 성장기 (1~4월), 성숙기 (4~5월), 완숙 및 방정기(6~8월), 회복기 (8~10월) 그리고 휴지기(10~12월)로 구분할 수 있었다.