Nitrate induces enzymes of the mannitol cycle and suppresses versicolorin synthesis in Aspergillus parasiticus.
Addition of sodium nitrate to growing cultures of Aspergillus parasiticus (ATCC 36537) induces the synthesis of enzymes involved in nitrate assimilation (NO3- reductase), of enzymes in the pentose pathway (glucose-6-phosphate dehydrogenase), and of enzymes in the mannitol cycle (mannitol- and mannitol-1-phosphate dehydrogenases). Addition of NO3- also causes a dose-dependent suppression of synthesis of the polyketide secondary metabolite, versicolorin A. We suggest that in the presence of NO3- plus peptone, the cytoplasmic NADPH/NADP ratio may be elevated, resulting in increased conversion of malonyl coenzyme A to fatty acid rather than to polyketide.
Niehaus
W G
WG
Biochemistry and Nutrition, Virginia Polytechnic Institute and State University, Blacksburg 24061.
Jiang
W P
WP
D000880:Anthraquinones / Q000378:metabolism*; D001230:Aspergillus / Q000187:drug effects / Q000201:enzymology*; D008354:Mannitol Dehydrogenases / Q000378:metabolism*; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism*; D009566:Nitrates / Q000494:pharmacology*; D010427:Pentose Phosphate Pathway
D000880:Anthraquinones; D009566:Nitrates; C005888:versicolorins; D008354:Mannitol Dehydrogenases; D009565:Nitrate Reductases; D050901:Nitrate Reductase