• Parasites, Hosts and Diseases
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• 제60권4호
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• pp.241-246
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• 2022

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

• Reproductive and Developmental Biology
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• 제30권2호
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• pp.93-97
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• 2006

To study the signaling effect of insulin-like growth factor-I(IGF-1), transgenic mice containing IGF-1 Receptor (IGF-1R) cDNA fused to metallothionein promoter were produced by DNA microinjection into the pronucleus of mouse zygote. Three founders were produced with transgenic mice containing IGF-1R gene. Transgenic mice lines contained approximately $4{\sim}20$ copies of transgenes per cell and transmission of this gene into the progeny with Mendelian manner were determined. The founder mice were mated with normal mice to produce $F_1$ mice and then $F_2$ mice. Transmission rates of IGF-1R transgene in the progeny mice were $25{\sim}60%$ in $F_1$ generation and $40{\sim}50%$ in $F_2$ generation. The mRNA expression of IGF-1R transgene in liver was analyzed using RT-PCR for IGF-1R gene in liver. When body weights of transgenic pups were measured during 4, 10 and 14 weeks after birth, IGF-1R transgenic mice grew faster than non transgenic littermates. This study indicated that growth regulation by IGF-1 signaling through IGF-1R can be elucidated using IGF-1R transgenic mice.

• Reproductive and Developmental Biology
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• 제29권4호
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• pp.235-239
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• 2005

This study was conducted to test whether the transgenic cattle pass the transgene to their progeny through germ cells, and whether the transgene is expressed in the mammary gland of ransgenic cows. Two male ransgenic calves were born from IVF-derived embryos injected with bovine $\beta-casein/human$ lactoferrin fusion gene and then grew up to be reproducible. Semen was collected from a transgenic bull after 18 mon of age and then frozen. Bovine oocytes matured in vitro were fertilized with spermatozoa of the transgenic bull and cultured in $50\;{\mu}L$ drops of CRlaa medium supplemented with 3 mg/mL BSA. After 48 h of culture, cleaved embryos were determined for the presence of transgenes by DNA polymerase chain reaction (PCR). Proportion of transgene positives among bovine embryos fertilized with sperm of the transgenic bull was $20.9\%$ (28/134). One of transgenic bulls did not produce transgenic sperm. Out of 34 calves produced from recipient heifers inseminated with semen of the other bull, 3 $(8.8\%)$ were transgenic animals (2 females and 1 male). Thus, one transgenic bull showed a low transmission frequency below Mendelian levels in both the IVF-derived embryos and his progeny. It was demonstrated by Southern blot that copy numbers of the transgene in the transgenic progeny enhanced about 1.8 times as compared to those of the founder bull The results demonstrate that the transgenic bull carrying human lactoferrin gene could pass his transgene to the progeny through germ cells, although he is a germ-line mosaic.

• Reproductive and Developmental Biology
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• 제28권3호
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• pp.147-153
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• 2004

The oocyte and its surrounding granulosa cells co-exist in a closed compartment called a follicle, although they receive many signals from other parts of the body. It is well established that the intercellular communications between the oocyte and granulosa cells are required for normal oocyte development and ovulation during folliculogenesis. Gap junctions are intercellular channels allowing the direct transmission of ions and small molecules between coupled cells. Several lines of studies have shown that multiple connexins (Cx, subunits of gap junction) are expressed in mammalian ovarian follicles. Among them, two major connexins Cx37 and Cx43 are expressed in different manner. While the gap junction channels formed by Cx37 are localized between the oocyte and encompassing granulosa cells, the intercellular channels by Cx43 are located between granulosa cells. In this review, I will summarize the general properties of gap junction channels and discuss their possible formation (or compatibility) of intercellular channels formed by the oocyte and granulosa cells.

• 전자통신동향분석
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• 제39권2호
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• pp.1-11
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• 2024

The metaverse is expected to evolve into an immersive environment based on photorealistic stereoscopic imaging to integrate real and virtual worlds. To transition from flat images to immersive stereoscopic images, such as light fields and holograms, a continuous cycle of technological development should be reached in media, content, and device technologies, ranging from acquisition and generation to transmission and synthesis as well as reproduction and interaction. Additionally, owing to the multitude of components involved in the metaverse, proper service realization will be challenging without concurrent advancements in computing and communication technologies that facilitate the integration of such components. We introduce research and development trends in media, contents, and devices at the Electronics and Telecommunications Research Institute toward the next generation of stereoscopic images.

• Nonlinear Functional Analysis and Applications
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• 제29권2호
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• pp.597-620
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• 2024

In this study, the conformable fractional derivative(CFD) of order 𝝔 in conjunction with the LC operator of orderρ is used to develop the model of the transmission of the A(H1N1) influenza infection. A brand-new A(H1N1) influenza infection model is presented, with a population split into four different compartments. Fixed point theorems were used to prove the existence of the solutions and uniqueness of this model. The basic reproduction number R₀ was determined. The least and most sensitive variables that could alter R₀ were then determined using normalized forward sensitivity indices. Through numerical simulations carried out with the aid of the Adams-Moulton approach, the study also investigated the effects of numerous biological characteristics on the system. The findings demonstrated that if 𝝔 < 1 and ρ < 1 under the CFD, also the findings demonstrated that if 𝝔 = 1 and ρ = 1 under the CFD, the A(H1N1) influenza infection will not vanish.

• 한국가축번식학회지
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• 제22권4호
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• pp.331-339
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• 1998

본 연구는 Sertoli 세포 column 과 Sertoli 세포돌기 미세구조의 연구를 위해 당질검출을 위한 PA-TCH-SP, -PD 투과전자현미경용 특수염색을 정세관에 적용한 후 각 정세포와 Sertoli 세포를 관찰하고 비교하여 이 분야 연구에 본염색법의 적용 가능성을 검토하였다. PA-TCH-SP, -PD 특수염색을 개의 정세관에 적용하여 투과전자현미경으로 관찰하였던 바, Sertoli 세포 column 과 돌기 부위에 수많은 반응과립이 관찰되었으며 정세관 기저부의 정조세포질에서도 약간의 반응과립이 관찰되었다. 이와 같은 반응과립은 각 정세포의 핵, 정모세포질, 정자세포질 및 잔류체에는 존재하지 않아 반응과립이 존재하는 Sertoli 세포 colunm 과 돌기 및 정자세포질에 침투된 돌기들을 명확히 구분할 수 있었다. 따라서 PA-TCH-SP, -PD 염색법은 투과전자현미경하에서 Sertoli 세포 colunm 과 돌기의 형태학적 및 기능학적 연구에 대단히 유용한 염색법으로 사료된다.

• 한국콘텐츠학회논문지
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• 제11권10호
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• pp.242-256
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• 2011

소셜미디어를 통해 개인의 일상을 공유하는 활동이 보편화되었다. 이 경우에는 텍스트뿐 아니라 사진도 많이 활용을 하게 되는데, 사진을 찍어 올리기가 손쉬운 만큼 타인의 사진을 스크랩하는 일도 매우 용이해졌다. 그러나 그 사진이 저작권법상 보호받는 사진저작물에 해당한다면 스크랩에 신중을 기할 필요가 있다. 타인의 사진저작물을 무단이용한 경우 저작권 침해가 성립하며, 이것을 내 블로그 등 소셜미디어에 게시한 경우에는 복제권 전송권 전시권을 침해하게 된다. 스크랩이 허용된 경우라 하더라도 그 사진저작물을 영리목적으로 사용하려면 별도의 허락을 얻어야 한다. 저작권 침해 논란에서 벗어나기 위해 타인의 사진저작물을 변형해서 사용하는 경우가 있는데, 이때에는 변형의 정도에 따라 복제권 동일성유지권 2차적 저작물작성권 침해가 이루어진다. 화면캡처의 기술이 발달하여 몇 번의 클릭만으로 타인의 사진저작물을 다운로드받을 수 있지만, 기술적으로 가능한 행위가 모두 합법적이지는 않다는 사실을 항상 인식하여야 한다.

• 한국가축번식학회지
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• 제26권4호
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• pp.353-360
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• 2002

Although successful pronuclear formation and apposition were seen in porcine oocytes following mouse sperm injection, little is known on the morphology of male and female pronuclei following sperm injection. The objective of this study is to describe the ultrastructure of porcine zygote following murine sperm injection in relation to the chronology of pronuclear S phase. At 40h ~ 44h following in vitro maturation, Cumulus cells were removed in TCM-HEPES with 0.1% hyaluronidase. Then, spermatozoa was injected into the cytoplasm of oocytes. After. injection, all oocytes were transferred to NCSU23 medium and cultured at 39$^{\circ}C$ under 5% $CO_2$ in air. Oocytes were fixed in 2% glutaraldehyde in Dulbeccos phosphate-buffered saline and observed by Transmission Electron Microscopy. Nuclear precursor bodies were observed in each pronucleus. A cluster of large and small granules was attached in the nucleolus precursor body. After the apposition of male and female chromatin, chromatin condensation was observed throughout the nucleoplasm and nucleolus precursor bodies and condensed chromatin in contact with clusters of small and large granules and the nuclear envelope were found in apposed pronuclear regions. These results suggest that non-species specific nuclear cytoplasmic interactions take place during pronuclear formation and apposition following sperm injection.

• Mycobiology
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• 제34권2호
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• pp.61-66
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• 2006

Chestnut blight disease caused by Cryphonectria parasitica is widely distributed throughout chestnut tree plantations in Korea. We surveyed 65 sites located at 9 provinces in South Korea, and isolated 248 virulent and 3 hypovirulent strains of chestnut blight fungus. Hypovirulent strains had dsRNA virus in the cytoplasm, which is one of the typical characteristics of hypovirulent strains. In addition, they showed more characteristics of hypovirulent strains, i.e., suppressed conidiation, reduced pigmentation in colony color, and reduced phenol oxidase activity as well as reduced pathogenicity. Hypovirulent strains, KCPH-22, KCPH-135 and KCPH-136, had a genomic dsRNA band with the molecular weight of 12.7 kb, which is the L-dsRNA of CHV1. They also had a 2.7 kb defective dsRNA band. Single conidia isolated from hypovirulent strains were cultured and various phenotypes and absence of dsRNA bands were obtained from single conidial cultures, which means that hypovirulence transmission is unstable in asexual reproduction and variations in viral heredity by asexual reproduction. Biocontrol trial using hypovirulent strains was also carried out in the chestnut tree plantations, and canker expansion in the treated trees was stopped and healed by callus formation at the margin of the canker. These results show the potentials in successful biocontrol of chestnut blight if the vegetatively compatible hypovirulent strains could be directly used around the canker formed by compatible virulent strains.