Effect of vitamin E on autolysis and sporulation of Aspergillus nidulans.
The morphologic and physiologic effects of vitamin E, a powerful antioxidant, on the autolysis and sporulation of Aspergillus nidulans FGSC26 were studied. In carbon-depleted submerged cultures, reactive oxygen species (ROS) accumulated in the cells and, concomitantly, progressing autolysis was observed, which was characterized by decreasing dry cell masses and pellet diameters as well as by increasing extracellular chitinase activities. Vitamin E supplemented at a concentration of 1 g/L hindered effectively the intracellular accumulation of ROS, the autolytic loss of biomass, the disintegration of pellets, and the release of chitinase activities. In surface cultures, vitamin E inhibited autolysis of both A. nidulans FGSC26 and a loss-of-function FlbA autolytic phenotype mutant. In addition, supplementation of the culture medium with this antioxidant also had a negative effect on the sporulation of strain FGSC26 and the FadAG203R hypersporulating phenotype mutant. These results suggest that accumulation of ROS was involved in the initiation of both sporulation and autolysis in this filamentous fungus, but that FadA/FlbA signaling was not involved in this vitamin E-dependent regulation. Vitamin E can be recommended as a supplement in fermentations in which the disintegration of pellets and gross autolysis should be avoided.
Emri
Tamás
T
Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, PO Box 63, H-4010, Hungary. emri@freemail.hu
Molnár
Zsolt
Z
Pusztahelyi
Tünde
T
Rosén
Stefan
S
Pócsi
István
I
D000975:Antioxidants / Q000494:pharmacology*; D001233:Aspergillus nidulans / Q000187:drug effects* / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D046508:Culture Techniques; D017382:Reactive Oxygen Species / Q000378:metabolism; D013172:Spores, Fungal / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology*
D000975:Antioxidants; D017382:Reactive Oxygen Species; D014810:Vitamin E; D002688:Chitinases