Stress situations induce cyanide-resistant respiration in spoilage yeasts.
OBJECTIVE
To investigate the conditions that promote the expression of cyanide-resistant respiration (CRR) in the spoilage yeasts Pichia membranifaciens and Debaryomyces hansenii.


RESULTS
CRR was detected by sensitivity of oxygen consumption to salicylhydroxamic acid. It was absent in both yeasts in the early exponential phase, but was triggered by several stress situations. Starvation under aerobic conditions, decreasing pH or incubation of the culture in a narrow temperature range below the maximum temperature for growth promoted the emergence of CRR in both yeasts. In D. hansenii, CRR was also induced by 1.5-2 mol l(-1) NaCl. Although the presence of H2O2 and menadione induced CRR, radical scavengers had no effect on the emergence of CRR. Also, the level of reactive oxygen species did not vary with the CRR activity.


CONCLUSIONS
Under aerobic conditions, a respiratory pathway alternative to the cytochrome chain is triggered by stress conditions in P. membranifaciens and D. hansenii.


CONCLUSIONS
The relationship between stress situations and CRR must be taken into account in studies on the performance of spoilage yeasts in the food processing environments where several forms of stress are common.
Veiga
A
A
Dep. Botânica e Engenharia Biológica, Instituto Superior de Agronomia, Lisboa, and Centro de Eng. Biológica, Fac. Ciências Lisboa, Lisboa, Portugal.
Arrabaça
J D
JD
Loureiro-Dias
M C
MC
D000968:Antimycin A / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D005285:Fermentation; D005511:Food Handling; D005516:Food Microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D024101:Mitochondrial Proteins; D018384:Oxidative Stress / Q000502:physiology; D010088:Oxidoreductases / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D010843:Pichia / Q000187:drug effects / Q000502:physiology; D010940:Plant Proteins; D011190:Potassium Cyanide / Q000494:pharmacology*; D013696:Temperature; D015003:Yeasts / Q000187:drug effects / Q000502:physiology*; D000099188:Alternative Oxidase
D000968:Antimycin A; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D011190:Potassium Cyanide; D000099188:Alternative Oxidase