• BMB Reports
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• v.28 no.5
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• pp.408-413
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• 1995

Decrease in the amount of cotyledonary spermidine in Glycine max under anaerobic conditions related to an increase in spermidine dehydrogenase. Under the same conditions, no enzymatic activity of diamine oxidase was observed. Exposure of Glycine max both to spermidine and 1,3-diaminopropane under anaerobic conditions resulted in a decrease in spermidine contents. Correlated with the decrease in spermidine contents, there was a drastic increase in spermidine dehydrogenase. The molecular weight of the purified enzyme estimated by Sephacryl S-300 gel column and SDS gel electrophoresis were 130,000 dalton and 65,000 dalton, respectively, indicating that the enzyme is a dimer. The optimal pH for activity was 9.3. The $K_m$ value for spermidine was 0.61 mM. Neither metal ions nor polyamine and derivatives affected enzymatic activity, but the enzyme was inhibited by DTNB, NEM and PCMB, suggesting that a cysteine residue of the enzyme is associated with or involved in enzyme activity. To our knowledge, this is the first report describing properties of the enzyme from plants. Considered together, the data in this paper indicate that both spermidine and 1,3-diaminopropane, novel activators, enhance the spermidine dehydrogenase activity and control the intracellular spermidine contents.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.533-538
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• 1992

The generation time of Methylobacterium extorquens AMI growing on methanol at pH 5.5 and 7.0 was found to be 23 hand 8.3 h. respectively. The bacterium grown at pH 7.0 were found to contain more amounts of spermidine and putrescine than the cell grown at pH 5.5. Cells grown at both conditions exhibited strong methanol dehydrogenase (MDH) activity at the mid-exponential growth phase. The amounts of MDH. however. were found to be almost equal through all gro~1h phases. Cells growing at the stationary phase contained large amounts of cytochrome c. The cytochrome c content was higher in cells growing at pH 7.0 than the cells growing at pH 5.5. Cells growing at pH 5.5 in the presence of putrescine or spermidine contained increased amounts of putrescine. The level of spermine, however. was decreased and that of spermidine was not changed. Spermine added into the medium was found to have no effect on the level of cellular polyamines. Putrescine or spermidine added into the medium stimulated MDH and hydroxypyruvate reductase activities. but did not affect the contents of MDH and cytochrome c. It was found that preincubation of cell-free extracts with polyamines does not stimulate MDH and hydroxypyruvate reductase activities.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.934-944
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• 2007

Paenibacillus polymyxa E681 is known to be able to suppress plant diseases by producing antimicrobial compounds and to promote plant growth by producing phytohormones, and secreting diverse degrading enzymes. In spite of these capabilities, little is known regarding the flow of information from the bacterial strain to the barley roots. In an attempt to determine the flow of information from the bacterial strain to barley roots, the strain was grown in the presence and absence of barley, and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and MALDI-TOF mass spectrometry were used. 2D-PAGE detected approximately 1,000 spots in the cell and 1,100 spots in the supernatant at a pH 4-10 gradient. Interestingly, about 80 spots from each sample showed quantitative variations. Fifty-three spots from these were analyzed by MALDI-TOF mass spectrometry and 28 proteins were identified. Most of the cytosolic proteins expressed at higher levels were found in P. polymyxa E681 cells grown in the presence of barley rather than in the absence of barley. Proteins detected at a lower level in the surpernatant of P. polymyxa E68l cells grown in the presence of barley were lipoprotein, glucose-6-phosphate 1-dehydrogenase, heat-shock protein HtpG, spermidine synthase, OrfZ, ribonuclease PH, and coenzyme PQQ synthesis protein, and flagellar hook-associated protein 2 whereas proteins detected at a higher level in the surpernatant of P. polymyxa E681 cells grown in the presence of barley included D-alanyl-D-alanine ligase A, isopentenyl-diphosphate delta-isomerase, ABC transporter ATP-binding protein Uup, lipase. Many of the proteins belonging to plant-induced stimulons are associated with biosynthetic metabolism and metabolites of proteins and transport. Some of these proteins would be expected to be induced by environmental changes resulting from the accumulation of plant-secreted substances.