• 한국동물학회:학술대회논문집
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• 한국동물학회 1995년도 한국생물과학협회 학술발표대회
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• pp.252.1-252
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• 1995

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• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1257-1263
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• 2011

This paper is dedicated to the study on the external and internal mass transfers of glucose for succinic acid fermentation under substrate and product inhibitions using a bioreactor with stirred bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the kinetic model adapted for both inhibitory effects, specific mathematical models were developed for describing the profiles of the substrate concentration in the outer and inner regions of biocatalysts and for estimating the substrate mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of the mass flows were significantly influenced by the internal diffusion velocity and rate of the biochemical reaction of substrate consumption. These cumulated influences led to the appearance of a biological inactive region near the particle center, its magnitude varying from 0 to 5.3% of the overall volume of particles.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 1991년도 춘계학술발표대회 논문집
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• pp.237-242
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• 1991

In order to increase the production of glutathione by maximizing the expression of recombinant gsh plasmids, two genes responsible for the biosynthesis of glutathione were cloned. A gshI gene was cloned onto pBR322 plasmid as 3.6Kb PstI DNA fragment from E. coli K-12 chromosomal DNA. Also gshII gene was cloned onto pUC13 plasmid as 2.2Kb PstI-BamHI DNA fragment. In order to improve the glutathione producing activity more efficiently, various recombinant plasmids containing tandem repeated gshI genes or both genes in various copy number onto the same vector were constructed. E. coli cells harboring pGH501 plasmid (pUC8-gshI$\cdot$I$\cdot$II) showed the highest glutathione synthesizing activity. The conditions for glutathione production with an ATP-generating system such as acetate kinase reaction of E. coli cells or glycolytic pathway of yeast cells were examined using the E. coli cells harboring the pGH501 plasmid. When the acetate kinase reaction of E. coli cells was used as an ATP generating system, 20mM of L-csteine was converted into glutathione with a yield of $100\%$.

• Journal of Plant Biotechnology
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• 제4권3호
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• pp.117-122
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• 2002

Cotton Glutathione S-Transferase(GST: EC 2.5.1.18) was cloned and Gh-5 cDNA was overexpressed in tobacco (Nicotiana tabacum) plants. The transformation of cotton GST in tobacco plant was confirmed by northern blot analysis. Type I and Type II transcript patterns were identified in Gh-5 transgenic tobacco plants. Type I transcripts was only discussed in this paper. Glutathione and 1-chloro-2,4-dinitrobenzene (CDNB) were used as the substrates, and the activity of GST in the type I transgenic plants was about 2.5-fold higher than the non-expressers and wild type tobacco plants. The expression of cotton GST in tobacco plants proved that Gh-5 could be translated into functional protein. Type I transgenic plants produced functional GST in the cells. Type I showed higher GST specific activity than Type II in the transgenic plants. Control and transgenic seedlings were grown in the growth chamber and under the light at 15$^{\circ}C$, and the effects of cotton GST in the seedlings was evaluated. The growth rate of Gh-5 overexpressors was better than the control and non-transgenic tobacco plants. Salinity tolerance was also analyzed on the seeds of transgenic plants. Seeds of Gh-5 overexpressors and the wild type tobacco seedlings were germinated and grown at 0, 50, 100, 150, and 200 mM NaCl solution. Gh-5 transgenic seedlings showed higher growth rate over control seedlings at both 50 and 100 mM NaCl solution. But at 0, 150, and 200 mM NaCl concentration, the difference in growth rate was not detected.

• The Korean Journal of Physiology and Pharmacology
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• 제2권1호
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• pp.101-108
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• 1998

We investigated the effect of ${\alpha}-subunit$ of the stimulatory GTP-binding protein ($G{\alpha}_s$) gene mutation on the expression of the thyrotropin-releasing hormone (TRH) receptor (TRH-R) gene in GH3 cells and in growth hormone (GH)-secreting adenomas of acromegalic patients. In the presence of cyclohexicmide, forskolin and isobutylmethylxanthine, cholera toxin, and GH-releasing hormone (GHRH) decreased rat TRH-R (rTRH-R) gene expression by about 39%, 43.7%, and 46.7%, respectively. Transient expression of a vector expressing mutant-type $G{\alpha}_s$ decreased the rTRH-R gene expression by about 50% at 24 h of transfection, whereas a wild-type $G{\alpha}_s$ expression vector did not. The transcript of human TRH-R (hTRH-R) gene was detected in 6 of 8 (75%) tumors. Three of them (50%) showed the paradoxical GH response to TRH and the other three patients did not show the response. The relative expression of hTRH-R mRNA in the tumors from patients with the paradoxical response of GH to TRH did not differ from that in the tumors from patients without the paradoxical response. Direct PCR sequencing of $G{\alpha}_s$ gene disclosed a mutant allele and a normal allele only at codon 201 in 4 of 8 tumors. The paradoxical response to TRH was observed in 2 of 4 patients without the mutation, and 2 of 4 patients with the mutation. The hTRH-R gene expression of pituitaty adenomsa did not differ between the tumors without the mutation and those with mutation. The present study suggests that the expression of TRH-R gene is not likely to be a main determinant for the paradoxical response of GH to TRH, and that $G{\alpha}_s$ mutation may suppress the gene expression of TRH-R in GH-secreting adenoma. However, a certain predisposing factor(s) may play an important role in determining the expression of TRH-R.

• Biomolecules & Therapeutics
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• 제3권4호
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• pp.294-300
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• 1995

DA-3002, an authentic recombinant human growth hormone(rhGH), was examined for mutagenicity in the reverse mutation test on bacteria, in the chromosomal aberration test on cultured mammalian cells and in the micronucleous test on mice. The reverse mutation test was performed by a plate incorporation method with or without a metabolic activation system(S9 Mix) using Salmonella typhimurium strain TA100, TA1535, TA98 and TA1537. DA-3002 did not significantly increase revertant colonies in any of the test strains under any conditions at dose levels ranging from 0.0125 to 0.4 IU/plate, compared with the vehicle control. In the chromosomal aberration test using cultured Chinese hamster lung(CHL) cells, DA-3002 did not increase the number of aberrant cells in the presence or absence of S9 mix at concentrations of 0.0125 IU/mι to 0.4 IU/mι, compared with the vehicle control. In the micronucleus test, male ICR mice were given DA-3002 intraperitoneally at a dose level of 20, 40 and 80 lU/kg. The incidence of bone marrow micronucleated polychromatic erythrocytes in the DA-3002 treated mice did not differ from that of the vehicle control. These results indicate that DA-3002 doesn't have mutagenic potential under the present test conditions.

• The Korean Journal of Physiology and Pharmacology
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• 제7권2호
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• pp.79-84
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• 2003

We have previously reported that expression of the somatostatin receptor subtypes, sst1-5, is differentially regulated by growth hormone (GH)-releasing hormone (GHRH) and forskolin (FSK), in vitro. GHRH binds to membrane receptors selectively located on pituitary somatotropes, activates adenylyl cyclase (AC) and increases sst1 and sst2 and decreases sst5 mRNA levels, without significantly altering the expression of sst3 and sst4. In contrast FSK directly activates AC in all pituitary cell types and increases sst1 and sst2 mRNA levels and decreases sst3, sst4 and sst5 expression. Two explanations could account for these differential effects: 1) GHRH inhibits sst3 and sst4 expression in somatotropes, but this inhibitory effect is masked by expression of these receptors in unresponsive pituitary cell types, and 2) FSK inhibits sst3 and sst4 expression levels in pituitary cell types other than somatotropes. To differentiate between these two possibilities, somatotropes were sequentially labeled with monkey anti-rat GH antiserum, biotinylated goat anti-human IgG, and streptavidin-PE and subsequently purified by fluorescent-activated cell sorting (FACS). The resultant cell population consisted of 95% somatotropes, as determined by GH immunohistochemistry using a primary GH antiserum different from that used for FACS sorting. Purified somatotropes were cultured for 3 days and treated for 4 h with vehicle, GHRH (10 nM) or FSK ($10{\mu}M$). Total RNA was isolated by column extraction and specific receptor mRNA levels were determined by semi-quantitative multiplex RT-PCR. Under basal conditions, the relative expression levels of the various somatostatin receptor subtypes were sst2＞sst5＞sst3=sst1＞ sst4. GHRH treatment increased sst1 and sst2 mRNA levels and decreased sst3, sst4 and sst5 mRNA levels in purified somatotropes, comparable to the effects of FSK on purified somatotropes and mixed pituitary cell cultures. Taken together, these results demonstrate that GHRH acutely modulates the expression of all somatostatin receptor subtypes within GH-producing cells and its actions are likely mediated by activation of AC.

• 한국발생생물학회지:발생과생식
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• 제4권2호
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• pp.237-242
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• 2000

흰쥐 시상하부에서 합성ㆍ분비되어 뇌하수체 전엽에서의 growth hormone (GH) 분비를 촉진하는 growth hormone releasing hormone (GHRH)이 시상하부 이외 조직들 (extrahypothalamic tissues)인 태반, 생식소, 그리고 뇌하수체 전엽에서도 발현됨이 보고되었다. 본 연구는 흰쥐 뇌하수체 전엽에서 발현되는 GHRH의 기능을 조사하기 위해 i)세포 배양을 시행하면서 GHRH의 세포내 함량, 분비 그리고 세포분획법 (cell-fractionation)을 사용하여 분리한 뇌하수체 세포 유형별로 GHRH 함량을 방사면역측정법으로 조사하였고, ii)체외배양 중인 뇌하수체 전엽세포의 증식에 미치는 GHRH의 효과를 측정하기 위해 [$^3$H] thymidine incorporation assay를, 그리고 iii) GHRH의 세포분열 촉진 효과와 세포내 c-fos 유전자 발현과의 상관관계를 조사하기 위해 northern blot analysis를 시행하였다. GHRH 방사면역측정법을 시행한 결과 상당량의 GHRH-like 분자들이 흰쥐 뇌하수체 전엽내에 존재하고, 체외 세포배양시 분비됨을 관찰하였다. 세포분획을 사용한 실험에서 GHRH 함량은 gonadotrope, somatotrope, lactotrope 그리고 thyrotrope 순으로 나타났다. 이 러한 결과는 흰쥐 뇌하수체 전엽에서 생성된 GHRH가 국부적인 조절인자, 특히 상이한 유형의 세포들 간의 상호조절 (cross-talk)을 통해 뇌하수체 전엽에서의 세포분열과 분화, 그리고 기능조절에 관여할 가능성을 보여주었다. GHRH는 체외 배양중인 뇌하수체 전엽세포의 [$^3$H] thymidine incorporation을 농도의존적으로 증가시켰으며, 이러한 GHRH의 세포분열 촉진 효과는 예상대로 세포내 oncogene 활성 의 증가를 통해 일어나는 것임을 c-fos northrn blot으로 확인하였다. 결론적으로, 본 연구는 흰쥐 뇌하수체 전엽에서 합성되는 GHRH가 paracrine 또는 autocrine 기작으로 GH의 분비 촉진 이외에도 세포분열의 조절함을 시사하는 것이다.

• Archives of Pharmacal Research
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• 제26권11호
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• pp.929-936
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• 2003

Methanol extract (MeOH), n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), butanol (BuOH) and aqueous ($H_2O$) fractions of Eucommiae Cortex including geniposidic acid (GA), geniposide (GP) and aucubin (AU) were tested for their therapeutic efficacy on osteoporosis. The contents of GA, GP and AU in the cortex and leaf of Eucommia ulmoides Oliver were quantified by HPLC. The effect of Eucommiae Cortex on the induction of growth hormone (GH) release was studied by using rat pituitary cells. The proliferation of osteoblast-like cells increased by herbal extracts was assayed using a tetrazolium (MTT), alkaline phosphatase (ALP) activity, and [$^3H$]-proline incorporation assays. The inhibition of osteoclast was studied by using the coculture of mouse bone marrow cells and ST-2 cells. As a result, the GA, GP and AU were present in the cortex more than in the leaf of E. ulmoides Oliver. The MeOH (1mg/mL), Hx, $CHCl_3$ and EA fractions (each 20 $\mu$ g/mL) had potent induction of GH release. The $CHCl_3$ exhibited the potent proliferation of osteoblasts. The AU, GP and GA were increased proliferation of osteoblasts. In addition, GA ($IC_{50}: 4.43{\times}10^{-7}$M), AU and GP were significantly inhibited proliferation of osteoclast. In summary, it is thought that the components in a part of the fractions of Eucommiae Cortex participate in each step of mechanism for activating osteoblast to facilitate osteogenesis, and suppress osteoclast activity to inhibit osteolysis.

• 대한수의학회지
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• 제33권1호
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• pp.37-42
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• 1993

The purpose of this study was to examine the effect of growth hormone(GH) on the division and migration of the small intestinal epithelium in mice. Twenty mice(ICR), weighing initially about 10 g, aged 18 days were randomly subdivided in two groups of control and GH-treated group. Control group was sacrificied at 2 hr, 2, 3, 4 and 5 day after intraperitoneal injection of $^3H$-thymidine($^3H$-TdR, $4{\mu}$ Ci/gm of BW/day for 2 days). GH-treated group was injected subcutaneously with somatotropin(10 IU/mouse/day for 4 days) from 2 day ago of first $^3H$-TdR injection and then was sacrificied at 2 hr, 2, 3, 4 and 5 day after intraperitoneal injection of $^3H$-TdR($4{\mu}$ Ci/g of BW/day for 2 days). The small intestines were collected for autoradiogrophy and Hematoxylin counterstain. The location of the labeled epithelial cells(LEC) in villi of the small intestine was invested with light microscope. 1. In the control group, the LEC regions in the small intestine were located at crypts on 1 dsy, at $0%{\sim}15.9{\pm}3.6%$ of villus high value(VHV) on 2 day, at $0%{\sim}49.8{\pm}16.5%$ of VHV on 3 day, at $0%{\sim}95.3{\pm}6.9%$ of VHV on 4 day and $62.9{\pm}16.7{\sim}100%$ of VHV on 5 day, respectively. 2. In the GH-treated group, the LEC regions in the small intestine were located at crypts on 1 day, at $0%{\sim}39.2{\pm}9.5%$ of VHV on 2 day, at $0%{\sim}81.5{\pm}18.2%$ of VHV on 3 day, at $45.2{\pm}11.5%{\sim}100%$ of VHV on 4 day, at 85%~100% of VHV on 5 day, respectively. 3. VHV of tops in the LEC regions appeared to be 23.3% and 31.7% higher on 2 and 3 day, and VHV of the LEC region bases appeared to be 45.2%, 22.1% higher on 4 and 5 day, respectively in the GH-treated group than those observed in the control group. These difference was very highly significant(p<0.01).