• 생명과학회지
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• 제9권4호
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• pp.460-465
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• 1999

In the giant freshwater prawn Macrobrachium rosenbergii, the paired testes were united by the testes bridge in a H-shape. During mating male discharged two hemispermtophores from right and left genital pore and they were joined and formed a compound spermatophore in peach shape. Hemispermatophore was considered to be produced at proximal and middle vas deferens region. The compound spermatophore consisted of an eosinophilic inner matrix, a basophilic outer matrix and paired sperm mass burried in the basophilic matrix. The size of compound spermatophore was 6.4∼ 9.3 mm in length and 2.4∼5.1 mm in width regardless of carapace length. After the spermatophore was deposited on female's ventral sternum behind of 5th pereiopod, it was moved to the ventral surface of 3rd and 4th pereiopods by means of the beating of male's 1st and 2nd pleopods.

• 식물조직배양학회지
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• 제27권5호
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• pp.359-366
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• 2000

Epigenetics represents a chromatin-mediated transcriptional repression which plays a control role in both animal and plant development. A number of different mechanisms have been described to be involved in the formation of chromatin structure: especially DNA methylation, nucleosomal histone modification, DNA replication timing, and binding of chromatin remodelling proteins. Epigenetic phenomena include genomic imprinting, dosage compensation of X-chromosome linked genes, mutual allelic interactions, paramutation, transvection, silencing of invasive DNA sequences, etc. They are often unstable and inherited in a non-Mendelian way. A number of epigenetic defects has been preferentially described in floral development. Here, epigenetic phenomena in model angiosperm plants and their corresponding mechanisms are reviewed.

• 한국조경학회지
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• 제21권1호
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• pp.83-94
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• 1993

After coming this century, as the propagative method of plants on a scientific foundation has been accompanied systematically, it has played an important part in the improvement of cultivar. But an existing propagative technique is not a few defects in our tasks and industrial structure which changes every hour and envirnment which undergoes a sudden change. To use developed biological knowledge recently, and existing propagative method which is main axis in sexual reproductive crossing, is increased much in the inside of internal organs by asexual reproductive means which is on a different level, and by, introducing a new character, it improves an inherited character etc. We have observed methods which supplement or replace a defect. These methods are not yet ripe for putting to practical use in the present research phase but convinced that they will offer an epoch-marking turning point.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.375-376
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• 2000

Sex ratio of a population is a key factor to determine reproductive rate of the population. If the population has skewed sex ratio to the male, the population size may decline gradually at an area which it inhabits, and, furthermore, if a species plays an ecologically important role in its community (e.g., a keystone species in Paine, 1966), its potential reproductive rate will be to form a characterized community because community structure is strongly influenced by the abundance of the ecologically important species (Hughes, 1986). A number of workers (e.g., Bryan et al., 1986 in Nucella lapillus; Spence et al., 1990 in Thais haemastoma) suggested that high frequency and/or late stage of imposex might affect the female mortality and normal reproduction adversely. Consequently, the imposex could affect sex ratio of natural population of some neogastropod including thaisid species. (omitted)

• 한국양식학회지
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• 제14권2호
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• pp.73-79
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• 2001

Testicular development of the male African lungfish, Protopterus annectens (Owen) was investigated histologically. The testis was found to be an elongated structure that possessed two distinct portions: an anterior spermatogenic part that was made up of a system of testicular tubules and a posterior vesicular part that invaded the kidney tissue. Spermatogenesis can be divided into five stages; primary spermatogonia, secondary spermatogonia, spermatocyte, spermatids and spermatozoa. Based on the gonadosomatic index (GSI) and histological changes observed, the reproductive cycle can be divided onto four distinct stages: resting and quiescent (December to February), growing (March to June) ripe and spent (July to August) and postspawning (September to November). The GSI was the maximum on July when reproductive cells were mature, ripe and ready for spawning; and the minimum in August after fish spawned.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.491-494
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• 2021

The article clarifies the definition and components of the ICT competence of future teachers, justifies the introduction of a motivational-value component. ICT competence of future teachers has a four-component structure: motivational-value, general-use, general pedagogical, subject-pedagogical components. The levels (reproductive, productive, creative), criteria and indicators of the formation of ICT-competence of students of a pedagogical college are determined, the content of these levels (reproductive, productive, creative) is disclosed, respectively.

• 한국수산과학회지
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• 제33권3호
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• pp.219-224
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• 2000

난소의 내부는 결체성 조직인 다수의 난소박판으로 구성되며, 이곳에서 난원세포가 유래한다 정소조직상은 정세관 형태이며, 각각의 정세관은 여러 개의 소낭구조를 가진다. 각 소낭내의 생식 세포들은 같은 단계의 발달상태를 보인다. 군 성숙도에 도달하는 크기는 암${cdot}$수 모두 전장 4.5 cm이다. 암컷의 GSI는 6월에 가장 높은 값을 나타냈으며, 수컷의 GSI는 7월에 가장 높은 값을 나타냈다. 생식주기는 성장기 ($1{\~}3$월), 성숙기 ($4{\~}5$월), 완숙 및 산란기 ($6{\~}7$월) 그리고 회복 및 휴지기 ($8{\~}12$월)로 나눌 수 있었다. 난모세포 발달양식은 난군동기발달형에 속하며, 초기 성장기 난모세포의 세포질에서 난황핵이 관찰되었다.

• Clinical and Experimental Reproductive Medicine
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• 제49권2호
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• pp.149-158
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• 2022

Objective: Optimizing culture media for the incubation of immature oocytes is a vital strategy to increase the oocyte maturation rate during in vitro maturation (IVM) programs. This study evaluated the IVM and fertilization rates of human germinal vesicle (GV) and metaphase I (MI) oocytes using two different maturation media (commercial and homemade) with or without growth differentiation factor 9-β (GDF9-β). supplementation. Methods: Immature oocytes from intracytoplasmic sperm injection (ICSI) cycles were collected and assigned to one of two IVM culture media (commercial or homemade; cleavage-stage base). After maturation, MII oocytes were examined under an inverted microscope for the presence of the polar body, zona pellucida (ZP) birefringence, and meiotic spindle (MS) visualization after maturation in four conditions (commercial or homemade medium, with or without GDF9-β. ICSI was done for matured oocytes, and fertilization was confirmed by the visualization of two distinct pronuclei and two polar bodies. Results: No significant differences were found between the two culture media in terms of the time and rate of oocyte maturation or the rate of fertilization (p>0.05). Growth factor supplementation increased the 24-hour maturation rate for both GV and MI oocytes only in homemade medium. The maturation rate after 24 hours was higher for MI oocytes (p<0.05). Similar results were observed for MS visualization and ZP structure in both types of media (p>0.05). Conclusion: Higher rates of oocyte maturation and fertilization were observed after application of homemade medium supplemented with GDF9-β. Therefore, this combination may be recommended as an alternative for clinical IVM programs.

• Clinical and Experimental Reproductive Medicine
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• 제51권1호
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• pp.20-27
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• 2024

Objective: While sperm freezing (cryopreservation) is an effective method for preserving fertility, it can potentially harm the structure and function of sperm due to an increase in the production of reactive oxygen species. This study aimed to assess the impact of zinc oxide nanoparticles (ZnONPs) and selenium oxide nanoparticles (SeONPs) on various sperm functional parameters, including motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), acrosome membrane integrity (ACi), and malondialdehyde (MDA) levels. Methods: Semen samples were collected from 20 Albino Wistar rats. These samples were then divided into six groups: fresh, cryopreservation control, and groups supplemented with SeONPs (1, 2, 5 ㎍/mL) and ZnONPs (0.1, 1, 10 ㎍/mL). Results: Statistical analysis revealed that all concentrations of SeONPs increased total motility and progressive reduction of MDA levels compared to the cryopreservation control group (p<0.05). However, supplementation with ZnONPs did not affect these parameters (p>0.05). Conversely, supplements of 1 and 2 ㎍/mL SeONPs and 1 ㎍/mL ZnONPs contributed to the improvement of PMI and ACi (p<0.05). Yet, no significant change was observed in MMP with any concentration of SeONPs and ZnONPs compared to the cryopreservation control group (p>0.05). Conclusion: The findings suggest that optimal concentrations of SeONPs may enhance sperm parameters during the freezing process.

• Clinical and Experimental Reproductive Medicine
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• 제26권1호
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• pp.43-54
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• 1999

Klinefelter's syndrome is a very important disease in gynecologic endocrinologic fields, because the patients with this karyotype complain of infertility, azospermia and ambiguous genitalia. Y chromosome is an important chromosome which determine genetic sex and the structure of gonad and genitalia. In this study, to elucidate the cytogenetic characteristics and clinical features of Klinefelter's syndrome and Y chromosomal abnormalities in Korea, we studied 303 cases of Klinefelter's syndrome and 11 cases of Y chromosomal abnormalities which were diagnosed by chromosomal analysis at the Cytogenetic Laboratory, Institute of Reproductive Medicine and Population, Seoul National University for 12 years from January 1984 to December 1996. The results of this study showed as follows: 1. In a total of 9275 cases, there were 303 cases (3.3%) of Klinefelter's syndromes, 11 cases (0.1%) of Y chromosomal abnormalities. 2. In 102 cases of patients showed typical clinical features of Klinefelter's syndrome, 101 cases (99%) of them were diagnosed to Klinefelter's syndrome in karyotyping. 3. In 303 cases of Klinefelter's syndrome, there were 277 cases (91.4%) of 47,XXY complement, 16 cases (5.3%) of mosaicism, 2 cases (0.7%) of 48,XXXY, 5 cases (1.7%) of 48,XXYY and 3 cases (1.0%) of 49,XXXXY. 4. In 303 cases of Klinefelter's syndrome, 284 cases (93.7%) of them were diagnosed after puberty and only 19 cases (6.3%) of them were diagnosed before puberty. 5. In 303 cases of Klinefelter's syndrome, there were 146 cases (48.2%) of patients with infertility-associated chief complaints, 101 cases (33.3%) of patients with typical clinical features of Klinefelter's syndrome, 22 cases (7.3%) of patients with ambiguous genitalia. 6. In patients with Klinefelter's syndrome, 48,XXYY and 49,XXXXY had serious symptoms such as mental retardation, developmental delay, Down syndrome-like features, congenital anomalies, but 48,XXYY and other mosaicisms had infertility-associated symptoms or ambiguous genitalia. 7. The 8 cases of polysomy Y (XYY complement) showed several serious symptoms such as Down syndrome-like features, mental retardation, fragile X syndrome-like feature, congenital anomalies, ambiguous genitalia which could be detected before puberty.