• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.87-93
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• 2011

S-Adenosylmethionine decarboxylase (SAMDC; EC 4.1.4.50), a key enzyme for polyamines biosynthesis, was tightly regulated for homeostatic levels. Carnation SAMDC gene (CSDC9) has an small upstream open reading frame (uORF) of 54 amino acids in 5'-leader sequence. To explore the functional mechanism of uORFs in controlling translation, we used a GUS reporter gene driven with the 35S promoter and uORF region of SAMDC gene for making transgenic tobacco plants. In our experiment, there were a translational inhibition of its downstream GUS ORF by SAMDC uORF sequence or SAMDC uORF protein. Expecially, translational inhibition was most effective in point-mutated construct, in which the start codon was changed. Therefore, this results suggested the ribosomal stalling might be involved in this translational inhibitory process. The frame shift in amino acid sequence of SAMDC uORF with start codon and stop codon resulted in a moderate increasing in GUS activity, suggesting the native amino acid sequence was important for a function as a translational inhibitor. Also, we showed that the production of GUS protein was significantly inhibited in the presence of the small uORF using histochemical analysis of GUS expression in seedlings and tobacco flowers. Importantly, the small uORF sequence induced a real peptide of 5.7 kDa, which was provided the presence of SAMDC uORF peptide band using an in vitro transcription/translation system. The peptide product of uORF might interact with other components of translational machinery as well as polyamines, which was resulted from that polyamine treatment was inhibited GUS protein band in SDS-PAGE experiment.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.54-61
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• 2011

Antisense construct of cDNA for senescencerelated ACC oxidase (CAO) cDNA isolated from carnation flowers were introduced into tobacco by Agrobacteriummediated transformation. The decreasing expression of NtACO and the reduction of ethylene production were observed in these transgenic lines. In contrast, the SAMDC transcripts and spermidine content were increased. The findings that higher content of spermidine in the ethylene suppressed transgenic plants compared with wild-type should be directly resulted in the enhancement of SAMDC activity followed by the increased accumulation of SAMDC transcript. To investigate the pathogenic response in these transgenic plants, wild-type and transgenic plants were inoculated with Phytophthora parasitica pv. nicotianae. Transgenic plants suppressing ethylene production showed the increased resistance against fungal pathogen, comparing with wild-type plant. PR-protein genes expression in CAO-AS-2 and CAOAS-4 were also higher at the normal growth condition and pathogenic response than in wild-type plants. The results of higher spermidine content and SAMDC activity in transgenic plants, CAO-AS-2 and CAO-AS-4, support the possibility that an increase in spermidine content might induce the higher transcripts of PR-protein genes. This results agreed with the phenomena that spermidine promoted the expression of PR1a and a SAMDC inhibitor, MGBG, decreased the expression of PR1a in leaf discs. These results suggest that the resistance against fungal pathogen in transgenic tobacco impaired in ethylene production might be caused by increasing in polyamine, especially spermidine, biosynthesis.

• BMB Reports
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• v.32 no.2
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• pp.173-180
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• 1999

The effects of agmatine on the enzymes responsible for the biosynthesis of polyamines, the resultant levels of polyamines, and their effect on the growth of DU145 human prostate tumor cells were investigated. When agmatine was added to the medium, ornithine decarboxylase (ODC, EC 4.1.1.17) activity was substantially reduced, but S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity increased markedly. These changes in ODC and SAMDC activities were the result of an induction of ODC-antizyme and a decreased turnover rate of SAMDC in the presence of agmatine. Accordingly, there was a decrease in the intracellular levels of putrescine and spermidine but an increase in the intracellular level of spermine. Cell growth was markedly inhibited by agmatine treatment and this inhibition was not recovered by the addition of putrescine or spermidine. Our results suggest that agmatine alters the intracellular amounts of polyamine in the cells, closely related to the inhibition of cell growth.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.335-338
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• 2005

For the development of qualitative PCR detection method of genetically modified rice (Oryza sativa L.), rice species specific gene, SAMDC1 (S-adenosylmethionine decarboxylase), was selected and validated as suitable for use as an endogenous reference gene in rice. The primer pair OsSAMDC1-5'/3' with 110 bp amplicon was used for amplification of the rice endogenous gene, SAMDC1 and no amplified product was observed from 19 different plants as templates. Qualitative PCR method was assayed with 2 different GM rices (Milyang 204 and Iksan 483) developed in Korea. For the qualitative PCRs, the construct-specific detection primer pairs were constructed. Os204-5'/OsNOS-3' amplifying the junction region of GUS gene and NOS terminator introduced in Milyang 204 gave rise to an amplicon 172 bp; also, Os483-5'/OsNOS-3' amplifying the junction region of Bar gene and NOS terminator introduced in Iksan 483 gave rise to an amplicon 161 bp.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.385-392
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• 1996

Changes in polyamine titers and enzyme activities during radicle growth of Glycine max were studied in order to investigate the effect of ferulic acid in regulation of polyamine biosynthesis. Among eight compounds used, gallic acid stimulated the radicle growth and ferulic acid inhibited it significantly. During the radicle growth of Glycine max, the content of putrescine was shown the highest level at the second day, while at the fourth day spermidine was the highest and spermine followed. Ornithine decarboxylass (ODC, EC 4.1.1.17) seems to be responsible for biosynthesis of putrescine. As the concentration of ferulic acid (0.001, 0.01, 0.1 mM) treated increased, the content of spermine was gradually enhanced and putrescine was increased at 0.001~0.01 mM, decreased after 0.1 mM concentration but spermidine was not affected. Ferulic acid elevated ODC and S-adenosylmethionine decarboxylass (SAMDC, EC 4.1.1.50) activity. ODC activity was increased more than 120% and SAMDC activity was increased about 50% more than that of the control. Diamine oxidase (DAO EC, 1.4.3.6) activity was enhanced about 20% at low concentration, decreased after then.

• Journal of Plant Biology
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• v.37 no.1
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• pp.101-109
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• 1994

Relationship between polyamine level and DNA methylation in the absence or presence of MGBG(l mM), which is an enzyme-activated reversible inhibitor of SAMDC, has been investigated during gametogenesis of Chlamydomonas. In the absence of MGBG, polyamine levels decreased in Chlamydomonas 137C(+) and 137C(-) during gametogenesis. And polyamine level of 137C(+) was 2-5 times as much as that of 137C(-) and showed a significant decrease unlike that of 137C(-). In vitro, MGBG inhibited ctDNA methylation of 137C(+) by 20-30% but did not inhibited that of 137C(-). Also, MGBG inhibited DNA methylase by 60% in vitro. The results obtained in the present work suggest the possibility that the changes of polyamine level may be associated with ctDNA methylation during gametogenesis of Chlamydomonas.omonas.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.223.1-223
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• 1997

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.194.1-194
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• 2003

No Abstract, See Full Text

• Journal of Ginseng Research
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• v.20 no.3
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• pp.233-240
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• 1996

In order to study effects of Korean ginseng (Panax ginseng C.A. Meyer) saponin fraction on polyamine metabolism in rat organs, Korean ginseng saponin fraction was administrated to rats for 1, 2, 3, 4, 6 and 12 months and brain, liver, prostate, spleen and testis were removed from these rats. Two enzyme activities were measured from those organs; ornithine decarboxylase (ODC), which is a regulatory enzyme of putrescence biosynthesis and S-adenosylmethionine decarboxylase (SAMDC), which is also a regulatory enzyme of spermidine and spermine biosynthesis. The amounts of polyamine were also determined. As for prostate and testis organs, Korean ginseng saponin fraction was innocuous for ODC and SAMDC activities from rats fed for 1 and 2 months. However, after 3 months, the stimulatory effect on the activities of two enzyme gradually increased in test groups and reached its maximum in 12 months. The contents of spermidine and spermlne of test groups in prostate and testis were also much higher than those of control groups. Another stimulatory effect on the activities of two enzymes was observed in liver and reached its maximum in 6 months. In the other organs such as brain and spleen, the enzymes were turned out to be not affected by feeding Korean ginseng saponin fraction. From the cumulative results, the stimulatory effect of Korean ginseng saponin fraction on polyamine metabolism was observed in prostate, testis and liver.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.323-334
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• 1996

Male Mongolian gerbils $(60{\sim}80g)$ were given DL-difluoromethylornithine (DFMO; 250mg/kg, ip) and methylglyoxal bis(guanylhydrazone) (MGBG; 50 mg/k, ip), respectively, 1 h prior to transient (7 min) occlusion of bilateral common carotid arteries (OBC7) and a daily dose of one of them for 6 days after recirculation, and the polyamine contents, activities of ornithine and S-adenosylmethionine decarboxylases (ODC and SAM-DC), and light microscopic findings of the hippocampus were evaluated. The hippocampal putrescine (PT) levels of the control gerbils treated with saline (STGr), markedly increased after OBC7, showing a peak level at 24 h after recirculation. The peak PT level was reduced in DFMO treated gerbils (DTCr) and in MGBG treated gerbils (MTGr). And 7 days after recirculation, the PT level of DTGr was decreased to about 75% of the PT level in the sham operated group (nonTGr) and to about 55% of the STGr level, respectively. The hippocampal spermidine (SD) level of STGr tended to decline, showing the lowest value at 8 h after recirculation. But the spermidine (SD) level of DTGr was somewhat higher at 8 h after OBC7 than those of STGr and MTGr The hippocampal spermine (SM) levels of all the experimental groups were little changed for 7 days after OBC. OBC7 markedly increased the hippocampal ODC activity. reaching a maximum (about 3 times higher than preischemic level) at 8 h and rapidly recovered to the control value by 24 h in STGr gerbils, and the OBC7-induced increase of ODC activity was significantly attenuated by DFMO or MGBG treatment. Whereas OBC7 induced a rapid decrease of the hippocampal SAMDC activity follwed by gradual recovery to the preischemic level, and the decrease of the SAMDC activity was slightly attenuated by DFMO or MGBG treatment. 7 Days after OBC7 the histological finding of the hippocampal complex stained with cresyl violet showed an extensive delayed neuronal damage in the CA1 region and to a lesser extent, in the dentate gyrus, sparing the CA3 region. And the neuronal death was aggevated by DFMO but significantly attenuated by MGBG. The immunochemical reactivity of hippocampus to anti-GFAP antibody was significantly increased in the CA1 region and to a lesser extent, in the dentate gyrus 7 days after OBC7, but was little changed in the CA3. And the increase of the anti-GFAP immunoreactivity was moderately enhanced by DFMO and significantly suppressed by MGBG. These results suggest that the polyamine metabolism may play a modulatory role in the ischemic brain damage.