Ultrastructural and functional differences in mitochondria isolated from Paramecium aurelia grown axenically and monoxenically.

Differences in the ultrastructure of mitochondria in $\text{P.}\text{aurelia}$ grown axenically and monoxenically have been observed. Functional mitochondria have been isolated from both cultures and various metabolic parameters have been tested; respiration rates, cytochrome content, oligomycin sensitive ATPase activity, and an attempt has been made to relate the observed structure and metabolic activity of the mitochondria to the growth conditions.