Folia Microbiologica

, 49:277

Physiological and morphological changes in autolyzingAspergillus nidulans cultures

Article

DOI: 10.1007/BF02931043

Cite this article as:
Emri, T., Molnár, Z., Pusztahelyi, T. et al. Folia Microbiol (2004) 49: 277. doi:10.1007/BF02931043

Abstract

Physiological and morphological changes in carbon-limited autolyzing cultures ofAspergillus nidulans were described. The carbon starvation arrested conidiation while the formation of filamentous and “yeast-like” hyphal fragments with profoundly altered metabolism enabled the fungus to survive the nutritional stress. The morphological and physiological stress responses, which maintained the cellular integrity of surviving hyphal fragments at the expense of autolyzing cells, were highly concerted and regulated. Moreover, sublethal concentrations of the protein synthesis inhibitor cycloheximide or the mitochondrial uncoupler 2,4-dinitrophenol completely blocked the autolysis. In accordance with the propositions of the free-radical theory of ageing reactive oxygen species accumulated in the surviving fragments with a concomitant increase in the specific superoxide dismutase activity and a continuous decrease in cell viability. Glutathione was degraded extensively in carbon-starving cells due to the action of γ-glutamyltranspeptidase, which resulted in a glutathione-glutathione disulfide redox imbalance during autolysis.

Abbreviations

CAT

catalase

DCF

2′,7′-dichlorofluorescein

DCM

dry cell mass

G6PD

glucose-6-phosphate dehydrogenase

GPx

glutathione peroxidase

GR

glutathione reductase

GSH

glutathione

GSSG

glutathione disulfide

GST

glutathione transferase

γGT

γ-glutamyltransferase

ICD

isocitrate dehydrogenase (NADP+)

MTT

3-(4,5-dimethylthiazol-2-yl)-2.5-diphenyl-2H-tetrazolium bromide

ROS

reactive oxygen species

SOD

superoxide dismutase

CuZn-SOD

Cu,Zn-superoxide dismutase

Mn-SOD

Mn-superoxide dismutase

Copyright information

© Institute of Microbiology, Academy of Sciences of the Czech Republic 2004

Authors and Affiliations

  • T. Emri
    • 1
  • Z. Molnár
    • 1
  • T. Pusztahelyi
    • 1
  • I. Pócsi
    • 1
  1. 1.Department of Microbiology and Biotechnology, Faculty of ScienceUniversity of DebrecenDebrecenHangary