• Journal of Plant Biology
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• v.37 no.2
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• pp.195-201
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• 1994

In order to study the effects of polyamine inhibitors and polyamines on adventitious root formation, the correlation between adventitious root formation and carbohydrate metabolism was investigated in inoculated soybean (Glycine max L.) cotyledons at the concentration of $10^{-3}\;M$ methylglyoxal bis-(guanylhydrazone)[MGBG], and $10^{-3}\;M$ MGBG plus $10^{-5}\;M$ polyamines (putrescine, spermidine and spermine), respectively, for the adventitious root formation medium. The contents of starch, maltose and sucrose were lower in control and were higher in the treatments containing $10^{-3}\;M$ MGBG, and $10^{-3}\;M$ MGBG plus $10^{-5}\;M$ polyamines during culture. It was shown that the soluble sugar levels, except glucose, were higher than that of control in most of the treatments and the change in glucose contents tended to be similar to that control. The amylase activity increased in control and MGBG treatment, the maltase activity was higher in control and the invertase activity showed less substantial changes during culture.ulture.

• Journal of Plant Biology
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• v.34 no.1
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• pp.53-57
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• 1991

The effect of polyamines and methylglyoxal bis(guanylhydrazone)(MGBG) on the activity of diamine oxidase was studied in soybean (Glycine max) seedlings. $10^{-2}\;M$ of putrescine, spennidine, and spermine inhibited diamine oxidase activity, whereas $10^{-6}\;M$ putrescine increased enzyme activity. These results suggest that diamine oxidase can be induced by a specific substrate, putrescine. The content of putrescine was increased in response to the increase in concentratioin of MGBG. In vitro, 40% of the diamine oxidase activity was inhibited by $10^{-3}\;M$ MGBG. In vivo, the diamine oxidase activity was increased by a low concentrration of MGBG. It was suggested that MGBG inhibited the formation of spermidine and that the accumulated putrescine induced diamine oxidase, whereas the diamine oxidase acitivity was inhibited by a high concentration of MGBG. It is suggested that a high cocentration of MGBG increases the putrescine content by inhibiting diamine oxidase activity which is responsible for putrescine degradation.dation.

• BMB Reports
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• v.28 no.3
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• pp.191-196
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• 1995

The role of polyamines in skeletal myoblast differentiation was investigated using the polyamine metabolic inhibitor methylglyoxal bis(guanylhydrazone)(MGBG). Concentrations of intracellular free spermidine and spermine increased 2 to 2.5-fold at the onset of myoblast fusion. The systhesis of actin, and creatine kinase activity both dramatically increased during myotube formation. However, MGBG at a concentration of 0.5 mM not only abolished the increase of intracellular free polyamines, but also reduced cell fusion to almost half the level of untreated cells, without noticeable morphological alteration. The production of actin, and creatine kinase activity were almost completely abolished by MGBG. The inhibition of myoblast fusion by MGBG was partially recovered with 0.1 mM of spermidine or spermine added externally. Results indicate that polyamines are necessary for normal myoblast differentiation. Since the first indication of myoblast differentiation is alignment of muscle cells and membrane fusion of adjacent cells, and since polyamine depletion completely inhibited the synthesis of actin, which might be associted with membranes, polyamine might be involved in myoblast differentiation through membrane reorganization events.

• Biomolecules & Therapeutics
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• v.5 no.3
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• pp.265-271
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• 1997

Since the advent of chemotherapy, certain types of cancer have been particularly resistant to chemotherapeutic treatment. One of the most well-studied types of resistance is resistance to multiple struc-turally dissimialr hydrophobic chemotherapeutic agents, or multidrug resistance (MDR). We found that MDR cells (KBV20C, KB7D) being highly resistant to colchicine, etoposide, and vincristine were found to have very low level of putrescine and low level of spermidine than the drug sensitive parental cells (KB) but they had almost same level of spermine as the drug sensitive cells. Although both MDR and drug sensitive cells had almost same rate of polyamine uptake, MDR cells were much more sensitive to an inhibitor of polyamine synthesis, methylglyoxal-bis guanylhydrazone (MGBG), suggesting that MDR cells might be defective in polyamine synthesis. These results also suggest that HGBG can be used for treatment of MDR in vivo.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.117-123
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• 2000

In order to study the role of polyamines on the formation of adventitious roots, trichomes and calli, the effects of putrescine, spermidine, spermine, cyclohexylamine (CHA) and methylglyoxal-bis(guanylhydrazone) (MGBG) were investigated in the leaf segment cultures from ecotype Columbia of Arabidopsis thaliana. When the leaf segments were cultured on the media for forming adventitious roots (0.1 mg/L NAA), trichomes (2.0 mg/L NAA) and calli (10.0 mg/L NAA), and then each cultures was treated with 1-100 mg/L of putrescine, spermidine and spermine, respectively. On the adventitious root-forming medium treated with polyamines the trichomes were induced with adventitious roots. And on the trichome-forming medium with polyamines calli were induced with trichomes. In orther hand each cultures was treated with 1-100 mg/L of CHA and MGBG, respectively. CHA promoted adventitious roots on the medium for adventitious roots, was not effected on media for trichomes and calli. MGBG inhibited adventitious roots, trichomes and calli in all cultures, and induced adventitious roots on medium for trichomes in high concentration.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.327-332
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• 1994

The effect of methylglyoxal-bis (guanylhydrazone) (MGBG) and ethylene synthesis inhibitors on adventitious root formation from soybean cotyledon in relation to ethylene production and endogenous polyamine content was investigated. Cotyledon explants cultured on rooting medium formed numerous adventitious rook on the cut surfaces after 2 weeks of culture. However when cultured on rooting medium supplemented with MGBG, the root formation was strongly inhibited, its inhibitory effect was reserved when cultured on medium with MGBG + spermine, MGBG + CoCl$_2$ and MGBG + spermine+CoC1$_2$. A slight reversion of the rooting inhibition was observed in 10$^{-3}$ M MGBG +10$^{-5}$ M spermine treatment, whereas it caused a significant effect in 10$^{-3}$ M MGBG +10$^{-4}$ M treatment .Ethylene production and endogenous polymine content was investgated in 10$^{-3}$ M MGBG , 10$^{-3}$ M MGBG +10$^{-5}$ Mspermine, 10$^{-3}$ M MGBG +10$^{-4}$ M CoCl$_2$and 10$^{-3}$ M MGBG +10$^{-5}$ M spermine +10$^{-4}$ M CoCl$_2$treatments. Ethylene production highest in 10$^{-3}$ M MGBG +10$^{-5}$ M spermine treatment was higher than control. In 10$^{-3}$ M MGBG +10$^{-5}$ M spermine + 10$^{-4}$ M CoCl$_2$ treatment, ethilene production was lowest, whereas polyamine level was highest.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.105-110
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• 1994

In order to study on the effect of polyamine inhibitors and polyamines on adventitious root formation the correlation between adventitious root formation and polyamine levels were investigated in cultured soybean (Glycine max L.) cotyledons. Adventitious root formation was inhibited in medium containing 10$^{-4}$ -10/ sup -2/ M polyamine inhibition such as $\alpha$-difluoromethylornithine (DFMO), $\alpha$-difluoromethylarginine (DFMA), cyclohexylammonium sulfate (CHA), dicyclohexyl-amine (DCHA) and methylglyoxal-bis (guanylhydrazone) (MGBG). An inhibitory effects at 10$^{-3}$ M MCBG were much higher than other treatments. Treatment with 10$^{-3}$ M MGBG plus 10$^{-5}$ M spermine led to reversal of the effects of MGBG alone. The polyamine levels were sharply increased in the first few days in each treatnent compared to control. The remarkably increasing polyamine contents were observed in medium supplemented spermine.

• Journal of Plant Biology
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• v.33 no.2
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• pp.87-96
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• 1990

The role of S-adenosylmethionine (SAM) as an intermediate in interrelation between polyamine and ethylene biosynthesis was studied in suspension cultures of Nicotiana tabacum L. Exogenous SAM stimulated the polyamine and ethylene biosynthesis in 4 day-cultured cells, which were in active cell divisions, and 10 day cultured cells, which went on with active cell elongation and senescence. SAM-induced ethylene production was more effective in 10 day-cultured cells than in 4 day-cultured cells, but SAM-induced polyamine biosynthesis was more effective in 4 day-cultured cells than in 10 day-cultured cells. Polyamine contents were increased by the blockage of ethylene biosynthetic pathway in the conversion of SAM to ethylene via 1-aminocyclopropane-1-carboxylinc acid (ACC) with aminooxyacetic acid (AOA). Also, ethylene production was increased by the inhibitors of polyamine biosynthesis such as methylglyoxal bis-(guanylhydrazone) (MGBG), dicyclohexylamine (DCHA), $\alpha$-difluoromethylarginine (DFMA) and $\alpha$-difluoromethylorinithine (DFMO). These results suggest that there may be interrelations between polyamine and ethylene biosynthesis for the competition of SAM and the inherent mechanism of switch on-off in polyamine and ethylene biosynthetic activity with the progress of cell growth and senescence.

• Journal of Plant Biology
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• v.35 no.4
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• pp.403-408
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• 1992

The flowering in Lemna gibba G3, a long-day plant, was promoted under continuous light by agmatine, putrescine, spermidine and spermine present in the culture medium. Methylglyoxal-bis (guanylhydrazone) (MGBG) and cyc10hexylamine (CHA), inhibitors of polyamine biosynthesis, were found to suppress the flowering in the plants. The vegetative grov.1h rate was kept constant while the flowering was being promoted by the pOlyamines, and the inhibitors with depressive effect on flowering showed stimulatory effect on vegetative grov.1h. The pattern of vegetative growth during floral promotion or depression was an indication that the promotive action of the pOlyamines and the suppressive effect of the inhibitors may be outcome of their possible involvement specifically in the flowering process rather than in broad spectrum of growth of L. gibba G3. The degree of promotive action of spermdine and spermine could not be altered (or lessened) by simultaneous application of their inhibitors to the medium. This phenomenon indicates that the flowering process in L. gibba G3 may largely be dependent to the status of endogenous spermidine and spermine. Endogenous level of spermidine in florally induced Lemna, was found to rapidly increase. In 24 h of floral induction, the content reached at the level 2 times higher than that in non-induced plants. The elevated level of spermidine provides an additional, though premature, evidence supporting the postulation that endogenous polyamine status might play an important role in the very early stage of floral induction in L. gibba G3.bba G3.

• 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.