Oxygen is toxic in the cold in C. elegans

Area of Science:

• Environmental Physiology
• Molecular Biology
• Animal Survival

Background:

• Temperature and oxygen levels critically impact animal survival, with extremes being lethal.
• Simultaneous low oxygen and temperature can enable exceptional survival in some animals.
• The specific role of oxygen in cold shock mortality remains an area of investigation.

Purpose of the Study:

• To investigate the role of oxygen concentration in the cold shock death of Caenorhabditis elegans.
• To explore the effects of cold acclimatization, genetic mutations, compounds, and antioxidant proteins on survival under combined cold and high oxygen stress.

Main Methods:

• Assaying survival of C. elegans populations across various oxygen concentrations and temperatures.
• Investigating the impact of cold acclimatization and specific genetic mutations on survival.
• Evaluating the protective effects of compounds (glucose, manganese (II), ascorbate) and antioxidant proteins (catalase, peroxiredoxin).

Main Results:

• C. elegans survival increased at 2°C when oxygen was deprived; however, even low oxygen (0.25 kPa) decreased survival.
• High oxygen levels (35-fold atmospheric) were lethal within 8 hours at room temperature and 2 hours at 2°C.
• Cold acclimatization, related mutations, glucose, manganese (II), ascorbate, catalase, and peroxiredoxin enhanced survival under cold shock and high oxygen conditions.

Conclusions:

• Oxygen toxicity is a significant contributor to Caenorhabditis elegans mortality during cold shock.
• Evolutionary pressures from oxygen toxicity in cold environments may drive the development of protective mechanisms.
• The protective roles of compounds and antioxidants suggest shared chemical environments under cold and high oxygen stress, potentially relevant to human physiology.