• 한국발생생물학회지:발생과생식
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• 제4권2호
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• pp.137-145
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• 2000

포유류 원시난포의 분화에는 뇌하수체에서 분비되는 gonadotropins 외에도 다양한 성장인자들 뿐 아니라 스테로이드호르몬 등이 관여하며, 난황낭에서 기원된 생식세포들과 중신에서부터 유입되는 기질세포들의 복잡한 상호작용에 의해 이루어진다. 특히 사람의 경우 태아기에 분화가 시작된 원시난포들은 성장을 개시한 후 배란이 되거나 혹은 폐쇄되어 난소에서 제거되는데, 일부 원시난포는 성장이 개시되기까지 50년 이상 원시난포의 상태로 유지된다. 그러나 원시난포의 분화 및 성장정지, 성장개시의 기전에 관하여는 현재까지 정확하게 밝혀져 있지 않다. 본 논문에서는 태아 및 신생아의 난소에서 gonadotrorin의 수용체, 성장인자와 성장인자 수용체, 그리고 스테로이드호르몬 수용체의 발현을 조사하였다. 이 결과들을 바탕으로 사람 원시난포의 형성, 성장정지를 조절하는 기전 그리고 원시난포의 성장개시에 영향을 미치는 요인을 알아보았다.

• Asian-Australasian Journal of Animal Sciences
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• 제8권6호
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• pp.557-562
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• 1995

In this study, characteristics of chick primordial germ cells (PGCs), which is the founder cell of the germline, and gonadal development of the chick embryo between 12hrs and 6 day of incubation were investigated by transverse serial sections of chick embryos under the light microscopic observation. In embryo stage 20 (3 day of incubation), there are a lot of PGCs at the mesenchym, which were moving to the thickened epithelium (gonadal ridge). The PGCs arrive at both right and left gonad primordial in equal number prior to stage 24 (4 day of incubation), but in the following stages, the distribution of the PGCs became asymmetrical. More PGCs colonized the left than the right gonad, but the reason for the unequal distribution of PGCs is uncertain. The PGCs have mostly settled in the gonadal ridge (GR) at 6 day embryo. This study was conducted to investigate characteristics of the PGC migration and gonadal formation and observe the best condition for PGC isolation, culture and to attempt the possibility of the production for transgenic germline chimeras with manipulated PGCs.

• 천문학회지
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• 제30권1호
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• pp.83-94
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• 1997

We have identified the candidates for the primordial galaxies in the process of formation in the Hubble Deep Field (hereafter HDF). In order to select these objects we have removed objects brighter than 29-th magnitude in the HDF images and smoothed the maps with the Gaussian filters with the FWHM of 0.8' and 4' to obtain the difference maps. This has enabled us to find. very faint diffuse structures close to the sky level. Peaks are identified in the difference map for each of three HDF chips with three filters (F450W, F606W, and F814W). They have the apparent AB magnitudes typically between 29 and 31. The objects identified in different wavelengths filters have a strong cross-correlations. The correlation lengths are about 0.8'. This means that an object found in one filter can be also found as a peak within 0.8' separation in another filter, thus telling the reality of the identified objects. This angular scale is also the size of the primordial galaxies which have strong color fluctuations on their surfaces. Their large-scale distribution quite resembles that of nearby galaxies, supporting the idea that these objects are ancestors of the present bright galaxies forming at statistically high density regions. Inspections on individual objects show that these primordial galaxy candidates have tiny multiple glares embedded in diffuse backgrounds. Their radial light distributions are quite different from that of nearby bright galaxies. We may be now looking at the epoch of galaxy formation.

• Clinical and Experimental Reproductive Medicine
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• 제39권4호
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• pp.127-131
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• 2012

Primordial follicles are formed prenatally in mammalian ovaries, and at birth they are fated to be activated to primary follicles, to be dormant, or to die. During the early stage of folliclulogenesis, the oocyte undergoes dynamic alterations in expression of numerous genes, which are regulated by transcription factors. Several germ-cell specific transcriptional regulators are critical for formation and maintenance of follicles. These transcriptional regulators include: Figla, Lhx8, Nobox, Sohlh1, and Sohlh2. A subset of these transcriptional regulators is mutated in women with ovarian insufficiency and infertility. Establishment of this oocyte pool is essential for fertility. This review focuses on these transcriptional regulators of female primordial follicles.

• 천문학회지
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• 제31권2호
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• pp.109-115
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• 1998

We show that the low density regions of the matter distribution preserve the properties of the primordial density field better than the high density regions. We have performed a cosmological N-body simulation of large-scale structure formation in the standard CDM cosmology, and studied the evolution of statistics of under-density and over-density regions separately. The rank-order of the under-density regions is closer to the original one compared to that of the over-density regions. The under-density peaks (or voids) has moved less than over-density peaks (or dense clusters of galaxies) from their initial positions. Therefore, the under-density regions are more useful than the over-density regions in the study of the statistical property of the primordial density field.

• Mycobiology
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• 제32권4호
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• pp.190-193
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• 2004

Six strains of Sparassis crispa such as S. crispa DUM-01, DUM-02, DUM-03, DUM-04, DUM-05, and DUM-06 were tested for their mycelial growth on 6 different kinds of sawdust media and primordial formation on 10 different compositions of larch sawdust media. The highest mycelial growth was recorded on the larch sawdust. Of the 6 strains of S. crispa, S. crispa DUM-04 recorded the favorable formation of primordia. The primordial formation of S. crispa DUM-04 was more favorable on L-3 medium than 9 kinds of larch sawdust media. When S. crispa DUM-04 was cultured on the media of larch sawdust+pine sawdust, the formation of its fruiting bodies was more outstanding on the media of larch sawdust+pine sawdust than those of larch sawdust.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.276-276
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• 2004

Pluripotent stem cells have been generated from two embryonic sources. ES cells are generated from ICM of blastocyst stage embryos, and embryonic germ (EG) cells are generated from primordial germ cells (PGCs). Both ES and EG cells are pluripotent and present important characteristics such as high levels of alkaline phosphatase (AP) activity, multi-cellular colony formation, normal and stable karyotypes, continuously passaging ability, and the capability of differentiation into all three embryonic germ layers. (omitted)

• 현장농수산연구지
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• 제12권1호
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• pp.21-27
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• 2010

The objective of this study was to determine the effects of "Green-one" organic nutrient on mycelial growth and fruiting of P. ostreatus. The dilution concentrations of "Green-one" was treated as follows. There was control, 100, 200, 400 concentrations. That treatments were treated with step of each mycelial growth step. The best of growth steps was mycelial scratching step. At that time, DPI(Day required for primordial formation after inoculation) was shortened for 1 day. Valid germination stipe are 15 pieces, 3 pieces more than control. Stipe length and stipe diameter was long each 4mm, 3mm more than control. Pileus size is shortened than control. Yields per one bottle(g/850cc) was 146g increased 6.5% than control 137g/850cc.

• 천문학회보
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• 제40권2호
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• pp.34.2-34.2
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• 2015

We aim to investigate the formation of primordial globular clusters (GCs) in the isolated dwarf galaxy (${\sim}10^{10}M_{sun}$) with cosmological zoom-in simulations. For this, we modified cosmological hydrodynamic code, GADGET-3, in a way to include the radiative heating/cooling that enables gas particles cool down to T~10K, reionization (z < 8.9) of the Universe, UV shielding ($n_{shield}$ > $0.014cm^{-3}$), and star formation. Our simulation starts in a cubic box of a side length 1Mpc/h with 17 million particles from z = 49. The mass of each dark matter (DM) and gas particle is $M_{DM}=4.1{\times}10^3M_{sun}$ and $M_{gas}=7.9{\times}10^2M_{sun}$, respectively, thus the GC candidates can be resolved with more than hundreds particles. We found the following results: 1) mini halos with the more interactions before merging into the main halo form the more stars and thus have the higher star mass fraction ($M_{star}/M_{total}$), 2) the mini halos with the high $M_{star}/M_{total}$ can survive longer and thus spiral into closer to the galactic center, 3) the majority of them spiral into bulge, but some of them can survive until the last as baryon-dominated system, like the GC.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2002년도 가을 학술발표논문집
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• pp.96-97
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• 2002

Primordial germ cells (PGCs) are the progenitors of the sperms or eggs of adult. Evidence suggests that the specification of primordial germ cells (PGCs) in the mammalian embryo does not depend on maternal determinants. Recent previous studies in the mouse has shown that several bone morphogenetic proteins (BMPs) are required for the formation of PGCs. However, there is no study about the effect of BMPs on avian PGCs. Here, we studied the effects of recombinant human BMP-2 (rhBMP-2) and recombinant human BMP-4 (rhBMP-4) on chicken blastodermal cells in culture. As a results, the addition of rhBMP-2 and rhBMP-4 increased the number of SSEA-1 positive cells in dose-dependent manner. However, there is no synergic effect by using both rhBMP-2 and rhBMP-4.