• Animal cells and systems
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• 제13권3호
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• pp.289-295
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• 2009

Cyclic AMP-mediated signaling pathways regulate a number of cellular functions. In this study, we examined the regulatory role of cAMP signaling pathways in chondrogenesis of chick limb bud mesenchymal cells in vitro. Forskolin, which increases cellular cAMP levels by the activation of adenylate cyclase, enhanced chondrogenic differentiation. Inhibition of PKA with specific inhibitors (H89 or KT5720) blocked pre-cartilage condensation stage, indicating that chondrogenesis is regulated by the increase in cellular cAMP level and subsequent activation of PKA. Downstream signaling pathway of PKA leading to gene expression was investigated by examination of several nuclear transcription factors. Forskolin treatment increased transcription level for a cartilage-specific marker gene Sox9. However, inhibition of PKA with H89 led to restore expression of Sox9, indicating PKA activity was required to regulate the expression of Sox9 in chondrogenesis. In addition, CREB was highly phosphorylated at early stage of mesenchyme culture, and followed by progressive dephosphorylation. CBP and ATF, another CRE related proteins were transiently expressed at the early stage of chondrogenesis with a pattern similar to CREB phosphorylation. Electrophoretic mobility shift assays confirmed that the binding activity of CREB to the CRE is closely correlated to the phosphorylation pattern of CREB. Therefore, cAMP-mediated signal transduction to nuclear events for the induction of genes appeared to be required at the early stage of chick limb bud chondrogenesis.

• 한국작물학회지
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• 제30권4호
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• pp.368-374
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• 1985

생장조절물질인 GA, Kinetin 및 2,4-D를 농도별로 처리하여 출아 및 생육특성을 조사하므로서 출아에 필요한 장기 저온기간의 단축 가능성을 탐색하였던 바 그 결과를 요약하면 다음과 같다. 1. 신아의 출아는 처리물질중 GA효과가 가장 컸으며 처리농도가 증가할수록 조기출아되어 출아기간이 단축되었고 출아율도 높았다. 2. GA처리는 지상부 생육을 크게 신장시켰으며 특히 경장 엽병장의 신장을 촉진시켰다. 3. GA 50ppm, 100ppm처리구는 근중을 크게 증가시켰다. 4. GA처리농도가 높을수록 조기에 지상부 생육이 완료되었다. 5. 뇌포제거구는 무제거구에 비하여 출아가 다소 빠른 경향이나 생육은 대체로 비슷하였다.

• The Korean Journal of Ecology
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• 제14권3호
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• pp.305-316
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• 1991

Growth hadit and demograph in a mature population of polygonatum and polygonatum humile in kanghwa island were studied for two growing seasons. Shoots of two species emerged early spring from the growing apices of the underdground rhizomes which had persisted for up to 1~5 year.after flowering, the ramets produced two rhizome buds at the shoot base. Bacause of the apical dominance in the rhizome system, a new rhizome was developed from only one bud, an actual bud,and the other latent buds were suppressed sothat remained dormant. The latent dud produced a new rhizome only when the actual dud was severed by the herbivores or by the physical obstacles. Therefore, the ramet number is not increased by the new rhizome from the latent bud. however, new ramets dould sometimes grow from latent buds which had been produced more than a year ago. Production of these ramets was main means increasing the ramet numbew and widening the potential zone of exploitation. Changes in size class of each ramet were noyiceable after a tear in small size-classes. Small ramets replaced themselves with larger-sized ramet, while large ramets with similar-sized or smallar-sized ramets. ramet numbers were average 0.82and 1.14 times of those fromthe previous year inp. involucratum and p. humile, though there was between-site variation. Almost all the ramets in the quadrats were alive during the growing season. when the entire rhizome systems were excavater next spring, there were many rhizomesegments without shoots, especially in p. involucratum. therefore, the drcrease of ramet number in p. involucratum in probably due to the climatic factors of winter.

• Journal of Plant Biotechnology
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• 제8권1호
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• pp.15-19
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• 2006

An efficient protocol for in vitro multiple shoot bud induction and plant regeneration from mature green cotyledon derived callus tissues of Acacia sinuata has been developed. Callus formation occurs at all the concentrations of thidiazuron (TDZ) in Murashige and Skoog's (MS) medium, but 0.6 ${\mu}M$ proved to be the best with maximum callus formation frequency. Supplementation of TDZ in combination with indole-acetic acid (IAA) in MS media accelerates shoot bud organogenesis in differentiating callus tissues with 60-70% conversion of shoot buds into shoot Most efficient shoot organogenesis was recorded when TDZ induced calli were subcultured at different concentrations of 6-benzyla-denine (BA). Optimum shoot bud induction and plant regeneration from callus was achieved when 0.6 ${\mu}M$ (TDZ) induced calli were subcultured at 3.0 ${\mu}M$ (BA) where $16.6{\pm}0.74$ shoots/unit callus on obtained. Rooting in in vitro differentiated shoots was achieved when transferred to medium containing different concentration of indole-3-butyric acid (IBA) in full & half strength MS medium. The well rooted plantlets were hardened and transferred to net house with 90% survival rate.

• 한국산림과학회지
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• 제94권2호통권159호
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• pp.67-72
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• 2005

The objectives of this study were to identify the period of initiation of floral primordia in black locust (Robinia pseudoacacia L.) and subsequent development of floral buds until following spring. Four mature trees of black locust located in Suwon, Korea were selected. Bud samples were collected from the current-year shoots, starting from mid June to July every week, from August to October and from February to April every month. The buds were fixed in FAA solution, dehydrated, and imbedded in paraffin for microscopic observation. Buds collected on June 16, and 23, 1997, contained primitive primordia that might be interpreted as early floral primordia. By June 30, a bud showed a positive indication of inflorescence primordium with a well-formed shoot apex. All the inflorescence primordia observed throughout the collection periods were always associated with unique hairy appendages around the primordium and enclosed within a sclerenchymatous chamber. By July 7 and 15, a floral apex had early bud scales. By July 22, primitive inflorescence developed into visible arrangement of individual floral primordial By July 29, the inflorescence developed into whirl arrangement of individual floral primordia in a transverse section, but showed little further development until October 15. The inflorescence primordia seemed to over-winter at this stage. Buds collected from February 15 and March 24 the following year also showed no further development of inflorescence primordia. By April 7 the inflorescence started to show further development with elongated axis. At this time individual flowers were easily recognized.

• 한국산림과학회지
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• 제57권1호
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• pp.45-51
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• 1982

잣나무의 착과량(着果量)에 미치는 기상환경인자(氣象環境因子)의 영향(影響)을 7개년간(個年間)의 착과량(着果量)과 기상자료간(氣象資料間)의 상관(相關) 및 회귀분석(回歸分析)을 통(通)해 연구(硏究)했다. 잣나무의 착과량(着果量)은 화아분화(花芽分化) 당년(當年) 년평균기온(年平均氣温)이 낮고 화아분화(花芽分化) 전년(前年) 일조량(日照量)과 화아분화전(花芽分化前) 동계기간(冬季期間)의 일조량(日照量)이 많을 때 증가(增加)되었으며 특(特)히 화아분화전(花芽分化前) 6월(月)의 기온(氣溫)이 낮고 강수량(降水量)이 적고 일조량(日照量)이 많을 경우 착과량(着果量)이 많았다.

• Journal of Microbiology
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• 제41권2호
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• pp.121-128
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• 2003

The identification of genes involved in true hypha formation is important in the study of mechanisms underlying the morphogenetic switch in yeast. We isolated a gene responsible for the morphogenetic switch in Yarrowia lipolytica, which forms true hyphae in response to serum or N-acetylglucosamine. The isolated gene, encoding 847 amino acids, had sequence identities of 27% and 25% with the Bud6 (Aip3) proteins of Saccharomyces cerevisiae and Schizosaccharomyces pombe, respectively. Disruption of this gene, designated YIBUD6, in haploid and diploid strains significantly reduced the ability of Y. lipolytica to switch from the yeast form to the hyphal form in hypha-inducing media. It was also found that YIBud6$\Delta$ mutants were rounder than the wild type when grown in the yeast form. These results indicate that the YIBud6 protein is necessary for hyphal growth and cell polarity in both haploid and diploid Y. lipolytica cells.

• Applied Microscopy
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• 제47권4호
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• pp.242-250
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• 2017

The purpose of this study was to characterize the prenatal and postnatal development of the mouse parotid salivary gland and tooth, and to investigate the relationship between the developmental timing of the two organs. Development of parotid salivary gland begins on embryonic day 15 (E15), which is the prebud stage; E17 is the initial bud stage; E21 to postnatal day 3 (PN3) is the pseudoglandular stage; PN5 to PN10 is the canalicular stage; and PN21 is the terminal bud stage. At E15, the developing maxillary molar tissue is at the bud stage; at E17, it is at the cap stage; at E21, it is at the early bell stage; PN3 to PN5 comprises the advanced bell stage; at PN10, it is at the crown stage; at PN21, it is at the functional stage. Therefore, unlike the other major salivary glands, the development of mouse parotid salivary gland is completed through a process of prenatal and postnatal morphogenesis and becomes functional at about the same time as the developing tooth. The developmental completion times of the parotid salivary gland and tooth are closely related to the weaning time of animal.

• Journal of Ginseng Research
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• 제26권1호
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• pp.17-23
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• 2002

Gibberellic acid (GA) was applied to field-grown 3-year-old North American ginseng (Panax quinqueiolius L.) between 1 and 4 times, before and during bloom in 1999. Applications of both GA$_3$ and GA$\sub$4+7/ four times (x4) to the developing inflorescences increased maximum pedicel length, and seed head diameter and height. Treatment with GA$\sub$4+7/ increased mean and total root fresh weight linearly, whereas those treated with GA$_3$ did not show similar increases. Both GA$_3$ and GA$\sub$4+7/ at 50, 100 and 200 mg L$\^$-1/ (x4) increased the incidence of breaking of dormancy of perennating buds with GA$_3$ being twice as effective as GA$\sub$4+7/. Both GA$_3$ and GA$\sub$4+7/ treatments resulted in an increased number of new bud initials forming per root, with the number of new initials per root increased two-fold by the GA$_3$ sprays compared to GA$\sub$4+7/.

• 식물조직배양학회지
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• 제25권4호
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• pp.263-266
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• 1998

파(Allium fistulosum L.)의 자방을 0.5mg/L NAA와 0.5mg/L BA 또는 0.5mg/L kinetin을 조합처리한 MS배지에서 배양하였을 때, 자방의 표면으로부터 화아발생 캘러스가 유도되었다. 화아발생 캘러스의 유지는 0.5mg/L NAA와 0.5mg/L kinetin이 첨가된 배지에서 계대배양 하였을 때 양호하였다. 배양 3-4주 후 화아들은 화아발생 캘러스로부터 형성되었지만, 계대배양을 거듭할수록 화아의 발생률이 감소하였다. 화아의 발생 단계별 조직학적 관찰 결과 돔형의 분열조직이 넓게 퍼지면서 자연상태의 꽃과 같이 외측에 화판, 내측에 심피와 배주가 기원된 후 성숙한 꽃으로 발달하였다.