Oxidative stress-induced Ca2+-signaling in Aspergillus nidulans may be required for survival.

Diana Bartelt, Mitra Singh, and Vilma Greene.


The effects of oxidative stress on levels of calcium ion (Ca2+) in Aspergillus nidulans were measured using strains expressing aequorin in the cytoplasm (Aeqcyt mt) [Greene, V., H. Cao, F. Schanne, and D. Bartelt. Cell. Signal. 14:437-443 (2002)]. When oxidative stress was induced by exposure to 10 mM H2O2, the mitochondrial calcium response (Ca2+mt) was greater than the change in cytoplasmic calcium (Ca2+c)and was dose-dependent,while the increase in [Ca2+c] did not change with increasing [H2O2]. Ruthenium red (RR) blocked the increase in [Ca2+mt]. Eighteen hour cultures of A. nidulans survived 30 min exposure to 100 mM H2O2 and, following exposure, conidiated normally when grown overnight in YG medium. Treatment with RR alone had no effect on growth and development. Pretreatment with RR prior to 100 mM H2O2 exposure, severely inhibited growth and conidiation. Cytoplasmic and mitochondrial fractions were prepared from cells exposed to H2O2,without and with RR pretreatment. ATP levels decreased, and isocitrate dehdrogenase (IDH) activity was induced in extracts of cells exposed to H2O2 alone. Pretreatment with RR decreased the loss of ATP and inhibited the activation of IDH. (Supported by NIGMS R15 GM52630)

abstract No: 

Fungal Genet. Newsl. 50 (Supl):abstract

Full conference title: 

22nd Fungal Genetics Conference
    • Fungal Genetics Conference 22nd (2001)