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TEMPERATURE‐SENSITIVITY OF LIGHT‐INDUCED PHASE SHIFTING OF THE CIRCADIAN CLOCK OF NEUROSPORA
Author(s) -
Nakashima Hideaki,
Feldman Jerry F.
Publication year - 1980
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1980.tb04016.x
Subject(s) - circadian rhythm , neurospora , conidiation , phase response curve , mutant , phase (matter) , atmospheric temperature range , biology , circadian clock , rhythm , phase response , darkness , amplitude , neurospora crassa , biophysics , genetics , chemistry , gene , medicine , botany , endocrinology , thermodynamics , optics , physics , organic chemistry
— Two new mutants of Neurospora craasa , designated hth‐1 and hth‐2 , have been isolated which allow clear expression of the circadian conidiation rhythm at high temperature (36°C). Both strains showed single‐gene segregation and produced similar phenotypes but mapped to different genetic loci. These mutants allowed an analysis of the effect of temperature on (1) light‐induced phase‐shifting of the circadian rhythm, (2) period length of rhythm, and (3) growth rate. The amplitude of the phase response curve to light was drastically reduced as the temperature was increased from 25°C to 34°C. Phase advances were decreased more than phase delays. As previously reported (Sargent et al. , 1966), the period length of the rhythm is temperature‐compensated below 30°C ( Q 10 ˜ 1) but not well‐compensated above 30°C ( Q 10 1.3–1.7). The decrease in amplitude of the light phase response curve occurred in both temperature ranges. Furthermore, the Q 10 value was lowered by addition of yeast extract in the high temperature range but not in the low range. Q 10 values for growth rate also differed in these strains both in the low temperature range (25–30°C) and the high temperature range (30–34°C).