Respiratory activity of the cryophilic alga 'Chlorella' saccharophila at different temperatures

This study deals with the respiratory activity of the cryophilic microalga “Chlorella” saccharophila to the growth temperatures of 4°C and 16°C. The analyses showed that this alga responded positively to the temperature rise by increasing its growth rate. Moreover, the higher temperature did not affect the ultrastructural organization of the algal cells. As regards the respiration rate, it did not show a substantial difference in algae grown at 4°C or 16°C. Respiration analyses, accomplished after treatments with inhibitors of the distinct mitochondrial electron transport pathways, as well as western analysis carried out with an antibody against the alternative oxidase (AOX), suggested that the lack of decrease in oxygen consumption at the lower temperature could depend on a great activity of the alternative cyanide-resistant pathway.