Inhibition of Ornithine Decarboxylase and Growth of the Fungus Helminthosporium maydis.
alpha-dl-Difluoromethylornithine (DFMO), a specific enzyme-activated inhibitor of ornithine decarboxylase, at 0.5 to 2.0 millimolar significantly inhibited mycelial growth and especially sporulation of Helminthosporium maydis in the dark; its inhibitory effect on sporulation was greatly increased under light conditions. Putrescine at 0.25 millimolar fully prevented the inhibitory effects of DFMO; the inhibition caused by the latter could not be prevented by cadaverine or CaCl(2). alpha-dl-Difluoromethylarginine, a specific enzyme-activated inhibitor of arginine decarboxylase, at 0.1 to 2.0 millimolar had a weak inhibitory effect on the fungus. The effect was not dependent on the inhibitor concentration and there was no detectable arginine decarboxylase activity in the fungus.
Birecka
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Department of Biological Sciences, Union College, Schenectady, New York 12308.
Garraway
M O
MO
Baumann
R J
RJ
McCann
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