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Effect of Vitamin E on Autolysis and Sporulation of Aspergillus
nidulans
Applied Biochemistry and Biotechnology
July 2004, Volume 118, Issue 1-3, pps. 337-348
Proceedings From the ICICB
(ISSN 0273-2289)
Tamás Emri (Department of Microbiology and Biotechnology, Faculty of
Sciences, University of Debrecen, PO Box 63, H-4010 Debrecen, Hungary)
Zsolt Molnár (Department of Microbiology and Biotechnology, Faculty of
Sciences, University of Debrecen, PO Box 63, H-4010 Debrecen, Hungary)
Tünde Pusztahelyi (Department of Microbiology and Biotechnology, Faculty
of Sciences, University of Debrecen, PO Box 63, H-4010 Debrecen,
Hungary)
Stefan Rosén (Department of Microbial Ecology, University of Lund,
Ecology Building, Sölvegatan 37, S-223 62 Lund, Sweden)
István Pócsi (Department of Microbiology and Biotechnology, Faculty of
Sciences, University of Debrecen, PO Box 63, H-4010 Debrecen, Hungary)
Abstract:
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
FadAG203Rhypersporulating 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.
Keywords: Aspergillus nidulans; vitamin E; menadione; sporulation;
autolysis; fadA; flbA
Language: English
Document Type: Original Research |
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