• Journal of Microbiology
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• v.34 no.1
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• pp.30-36
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• 1996

We have exmained the re-establishment of HIMRE mediated silencing function on the transcriptional activity of yeast heast shock gene HSP82. To test whether the onset of SIR repression can occur in growing cells in the rpesence of a potent inhibitor of DNA replication, HMRa/HSP82 strains with SIR4- and SIR4S$^{+}$ genetic backgrounds were arrested in S phase by incubation of a culture in 200 mM hydroxyurea for 120 min. It was clear that following a 20 minute heat shock, silencing of the HMRa/HSP82 allele in cells pretreated with hydroxyurea does occur in a SIR4-dependen fashion, even though the kinetics of repression appears to be substantially delayed. We also have tested whether re- establishement of silencing at the HMR/hsp82 locus can occur in G1-arrested cells. Cell cycle arrest at G1 phase was achieved by treatment of early log a cell cultures with .alpha.-factor mating pheromone, which induces G1 arrest. The result suggests that passage through S phase (and therefore DNA replication) is nor required for re-establishing silencer-mediated repression at the HMNRa/HSP82 locus. Finally, to test whether de nono protein synthesis is required for re-establishment of silencer-mediated repression, cells were pretreated with cycloheximide (500 /.mu.g/ml) 120 min. It was apparent that inhibiting protein synthesis delays, but does not prevent, re-establishment of silencer-mediated repression. Altogether, these results indicate that re-establishment of silencer-mediated repression is not dependent on the DNA replication and has no requirement for protein synthesis.s.

• Korean Journal of Animal Reproduction
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• v.22 no.3
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• pp.265-276
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• 1998

In an attempt to evaluate the function of MAP kinase of porcine oocytes and to develop a method of assessment for kinase activity, we used MBP as a substrate to detect the MAP kinase activity of porcine oocytes matured in in vitro. The MAP kinase which had lower activity during the first 20 hours of culture started to show an increased amount of activity at 25 hours at which a collapse in nuclear membrane was induced. Significant (P<0.05) a, pp.ared at 30 hours of being cultured. The gel phosphorylation method, MBP which has been known to be a substrate for kinase such as cdc2 kinase, was phosphorylated at two positions corresponding to ERK 1 (44kDa) and ERK2 (42 kDa) which are known as mammalian MAP kinase. The existence of MARKK and MAP kinase were identified with western blotting at 0 hour culture of immature GV oocytes. The amount of those proteins did not increase during 40 hours of culture, which suggest that the increase of MAP kinase activity was caused by phosphorylaton rather than due to change in protein amount. MAPKK and MAP kinase were shown to be dephosporylated with deactivated at M 1 stage by inhibition of protein synthesis with cycloheximide added at the strat following the cultrue. We have reulsts that indicate the existedence of MAP kinase cascade which was activated simultaneously with start of porcine oocyte maturation (GVBD).

• YAKHAK HOEJI
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• v.41 no.1
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• pp.81-85
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• 1997

Ceramide has been suggested as an important mediator of the effects of extracellular agonists on cell growth inhibition, differentiation, apoptosis. However the biochemical sign aling mechanism involved in transducing the effects of ceramide on leukemia cell differentiation is still unclear. In these respects, we examined the regulatory effects of ceramide on c-jun gene expression during differentiation. In U-937 cells. ceramide increased c-jun mRNA levels in a time-dependent manner. The half life, of c-jun mRNA was 30 min. In contrast, inhibition of protein synthesis with cycloheximide in the absence, of transcription with actinomycin D increased the half-life of c-jun mRNA in ceramide-treated U-937 cells to more than 90 min. In order to examine whether ceramide-inhibited c-jun gene expression is regulated through ceramide-activated protein phosphatase (CAPP), a direct target for the action of ceramide, okadaic acid were treated to the cells. Okadaic acid inhibited enhancement of c-jun mRNA induced by C2-ceramide in a dose-dependent manner. These results suggested that ceramide increases c-jun mRNA level during differentiation in U-937 cells and regulates the gene expression on posttranscriptional level. In addition, we provide the evidence that CAPP is involved in ceramide-induced c-jun gene expression in U-937 cells.

• Environmental Analysis Health and Toxicology
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• v.18 no.4
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• pp.249-254
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• 2003

본 연구는 환경호르몬(endocrine disruptors)으로 분류되었으며, 에스트로젠 화합물의 특성을 지닌 4-Nonylphenol (NP)이 설치류 Pituitary 세포 중 성장호르몬을 분비하는 GH3 세포의 Nitric oxide(NO)을 증가시키는 작용기전을 규명코자 수행되었다 먼저 GH3세포에 NP처리 농도에 따른 NO의 생성을 측정한 결과 NP처리농도 의존적으로 증가시켰다. 이러한 NO의 증가가 genomic action인지를 확인하기 위해 GH3세포의 NO를 증가시키는 효소인 neuronal oxide synthase의 단백질량을 측정한 결과 GH3세포에서 NP에 의한 nNOS의 단백질의 변화는 없었다. 에스트로젠 화합물인 NP가 에스트로젠 리셉터 (ER)와의 관계를 조사하기 위해 ER억제제(ICI 168,780)클 처리한 경우 NP에 의해 증가한 NO가 감소하였다. 또한 유전자 전사억제제인 actinomycin D 및 단백질 발현 억제제인 cycloheximide을 처리한 경우는 NP에 의한 NO 증가억제효과가 없었다. 이러한 결과를 종합해 볼 때 GH3 세포에서 NP는 ER을 매개한 non-genomic action에 의해 NO를 증가키는 것으로 사료된다.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.99-102
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• 1999

Glucose - induced arginine transport system was induced by a exogenous application of NH$_4$^+ ion. The uptake rate of arginine (Arg) depended on the external NH$_4$^+ ion concentration. The uptake rate was inhibited by the presence of NH$_4$^+ ion within 1 min, whereas it increased maximally after 30 min. Glucose and NH$_4$^+ ion induced the same arginine transport system. Km value of Arg transport systems was 2 $\mu$M, and V_(max) was 60 $\mu$mol^(-1) . h . g fresh weight^(-1) for NH$_4$^+ ion and 174 $\mu$mol^(-1) . h . g fresh weight^(-1) for glucose induced transport system. But, the transport system of Glu for glucose and NH$_4$^(-1) ion induced had different Km values. Km value of Glu was 285 $\mu$M for glucose - and 58 $\mu$M for NH$_4$^+ ion induced transport system. Thus, NH$_4$^+ ions play a important role as inducer for the glutamine transport system. NH$_4$^+ ion induced glutamine system was inhibited over 90% by cycloheximide. We concluded that a new carrier protein for glutamine was induced by NH$_4$^+ ion.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.289-299
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• 1998

In this present study, we investigated the effects of red ginseng extract and its active constituents - Rbl , Re, Rgl on cycloheximide (CXM)-induced amnesia in the passive avoidance task in rats. Red ginseng water extract at 0.05-0.5 g/kg could improve CXM-induced amnesia in rats, Furthermore, the recovery effect of Rbl at 10 mghg administered 30 min before training trial from CXM-induced amnesia was better than those of Rbl administered other time before or after training trial. Rbl at 0.001-0.1 mghg could significantly improve CXM-induced amnesia and at 1 mghg completely augmented, but at 10 mghg its improving effect slightly weakened. Rgl and Re at 0.3-10 mghg could significantly improve CXM-induced amnesia and Rgl at 10 mg/kg completely avgmented. On the other hand, Rbl at 10 mghg could prolong the step through latencies in the training trial. These results suggest the beneficial effect of red ginseng extract on CXM-induced amnesia in rats could mainly due to the contribution of its active constituents - Rbl, Re, Rgl. The improving effect of Rbl on CXM-induced amnesia was best among the three active constituents. But the reduction in the improving effect of Rbl at 10 mg/kg might be due to the decrease in motor activity and attention to the passive avoidance task.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.366-372
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• 1989

Twenty-one strains were tested for 11$\beta$-hydroxylation of Reichstein's substance S. Four fungi exhibited ability for the reaction, among which Pellicularia fillamentosa showed the highest activity. The 11$\beta$-hydroxylase of this fungus was proved to be induced by the substrate, cycloheximide reducing significantly the activity of the enzyme. Range of optimum pH for the 11$\beta$-hydroxylation was broad and found to be 2.0-8.0. Test of the enzyme activity at different growing stages, from spore to mycelia, showed that the branching stage of hyphae and the mature mycelial stage were the most effective for the Reichstein's substance S transformation. However, 11$\beta$-hydroxylase in the intact spore was turned out to be uninducible with the substrate.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1646-1649
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• 2006

Protein synthesis is the ultimate outcome of gene expression which, in turn, is regulated by several translation factors. We attempted to identify substances that can inhibit the translation process in vitro when the outcome protein is luciferase. To this end, we developed a sensitive cell-free protein synthesis assay using luciferase as the reporter. The synthesis of luciferase increased proportionately as mRNA was added to a $15-{\mu}l$reaction medium in concentrations raging from 5 ng to 500 ng. The maximum amount of luciferase was synthesized when the media were incubated at $25^{\circ}C$ for 40 min. The concentration of each compound that inhibited luciferase production by 50% ($IC_{50}$) was calculated. Hygromycin, puromycin, and cycloheximide yielded an $IC_{50}$ of 0.008, 0.8, and $0.7{\mu}g/ml$, respectively. A filtrate of Streptomyces spp. isolates inhibited protein synthesis up to S-fold when added to the in vitro translation assay mixture.

• The Korean Journal of Pharmacology
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• v.31 no.2
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• pp.233-239
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• 1995

To verify the effect of immunosuppressants on the endotoxin-induced increase in iNOS activity, the action of immunosuppressants, dexamethasone (1.5 mg/kg), azathioprine (5 mg/kg/day) and cyclosporine (10 mg/kg), were evaluated in mice pretreated with LPS. The intraperitoneal injection of lipopolysaccharide (10 mg/kg) increased the nitric oxide synthase (NOS) activity in the brain and liver to maximum at 1 and 3 hours, respectively. The increase in NOS activity was blocked by the treatment with NOS inhibitor, LNAME(300 mg/kg) and aminoguanidine(100 mg/kg); a protein inhibitor, cycloheximide (10 mg/kg); and a transcription inhibitor of inducible NOS(iNOS), dexamethasone(1.5 mg/kg). Immunosuppressants, azathioprine (5 mg/kg) and cyclosporine (10 mg/kg), effectively blocked the increase in NOS activity. These results suggest that iNOS expression plays an important role in LPS-induced the increase in NOS activity and that immunosuppressants can be used as candidate for therapeutic agents in endotoxemia.

• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.381-388
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• 1996

맥류세균성 줄무늬병균의 선택배양기(KM-1)를 개발하여 이병식물체 및 토양으로부터 Xanthomonas campestris pv. translucens를 선택적으로 분리할 수 있는 효율성을 검토하였다. KM-1배양기의 구성성분은 증류수 1 L당 lactose 10 g, D(+)trehalose 4.0 g, thiobarbituric acid 0.2 g, K\ulcornerHPO\ulcorner 및 KH\ulcornerPO\ulcorner 각각 0.8 g, yeast extract 30 mg, NH\ulcornerCl 1 g, cycloheximide 100 mg, tobramycin 8.0 mg, ampicillin 1.0 mg 및 Bacto agar 15 g이며 1 N NaOH로 pH 6.6으로 조절하였다. X. c. t.의 균주별 KM-1의 배양효율은 비선택성 농후배지인 Wilbrinks agar에 비하여 1.30정도였으며, 기타 토양전염성식물병원세균 Agrobacterium tumefaciens, Agrobacterium rhizogenes, Erwinia carotovora var. atroseptica, Erwinia carotovora var. carotovora, Corynebacterium insidiosum, 및 기타 토양생존 부생세균 Bacillus cereus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Pseudomonas putida 등의 생장을 완벽하게 억제하였다. KM-1의 저장기간(shelf-life)도 5$^{\circ}C$에서 2개월 동안 선택성을 유지하였다. 따라서 본 병원균의 전염원의 생존 등 발생생태연구에 활용될 수 있는 가치가 충분히 인정되었다.