ABSTRACT
In synchronized light-dark cycles, stationary-phase cultures of the budding yeast Candida utilis were able to survive heat treatment at 50 degees C with an apparent circadian-like rhythm related to the onset of light. However, in continuous darkness this pattern did not run freely and was markedly dampened. We discuss these findings in terms of the potential circadian control of heat tolerance, which has been described in the fission yeast Schizosaccharomyces pombe. Our results suggest that the resistance pattern observed in C. utilis is most likely an adaptive response to the light-induced generation of reactive oxygen species rather than the occurrence of a truly endogenous circadian rhythm.
Subject(s)
Candida/physiology , Candida/radiation effects , Circadian Rhythm/radiation effects , Hot Temperature , Light , Adaptation, Physiological , DarknessABSTRACT
In synchronized light-dark cycles, stationary-phase cultures of the budding yeast Candida utilis were able to survive heat treatment at 50ºC with an apparent circadian-like rhythm related to the onset of light. However, in continuous darkness this pattern did not run freely and was markedly dampened. We discuss these findings in terms of the potential circadian control of heat tolerance, which has been described in the fission yeast Schizosaccharomyces pombe. Our results suggest that the resistance pattern observed in C. utilis is most likely an adaptive response to the light-induced generation of reactive oxygen species rather than the occurrence of a truly endogenous circadian rhythm (AU)
La supervivencia de cultivos de Candida utilis en la fase estacionaria tras ser sometidos a temperaturas de 50ºC en ciclos sincronizados de luz/oscuridad presentó un aparente ritmo circadiano relacionado con el inicio de la fase iluminada. Sin embargo, en condiciones de oscuridad continua este patrón no se observaba tan claramente y mostraba una marcada ambigüedad. Estas observaciones se discuten en términos de un posible control circadiano de la tolerancia a altas temperaturas, que ha sido descrito para la levadura Schizosaccharomyces pombe. Nuestros resultados indican que el patrón de resistencia observado en C. utilis es muy probablemente una respuesta adaptativa a la generación de especies reactivas de oxígeno inducida por luz y que no existe un verdadero ritmo circadiano endógeno (AU)
