ISSN:
1432-072X
Keywords:
Key words Heat shock
;
Ethanol
;
cAMP
;
Protein
;
kinase A
;
cGMP
;
Inositol phosphates
;
Calcium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Exposure of growing hyphae of Neurospora crassa to heat shock (44 °C) or ethanol (2.6 M) for 1 h induced a significant increase in the cAMP level, which reached a maximum approximately 2 min after the beginning of treatment and then decreased to control values despite continued heat or ethanol exposure. A 10-s heat shock or a 5-s ethanol shock also resulted in a transient cAMP increase 2 min after the pulse. Heat shock or ethanol treatment led to an increase in the amount of catalytic subunits of the cAMP-dependent protein kinase A in the nucleus almost synchronously with the increase of cAMP in the cytoplasm. The concentration of cGMP decreased a few seconds after the beginning of heat shock (44 °C) or ethanol treatment (2.6 M) to approximately 50% of the control level. Exposure to heat shock (44 °C, 1 h) led to an increase in the amount of inositol phosphates 0.5–2 min after the onset of heat shock. Thereafter, inositol phosphate levels dropped to control values despite continued heat exposure. Incubation of growing hyphae with cAMP or 8-Br-cAMP led to a two- to threefold increase of inositol phosphates 10–300 s after the beginning of incubation. Heat treatment furthermore caused a rapid release of calcium from vacuoles as determined by Fura-2 measurement of the calcium content released from isolated vacuoles. These heat-shock-dependent second messenger changes may play a role in the heat-shock-induced phase shifts of the circadian clock and heat-shock-induced conidiation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002030050633
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