MORPHOMETRIC STUDY OF THE CHANGES IN YEAST TORULOPSIS-SPHAERICA CHONDRIOME INDUCED WITH HE-NE-LASER IRRADIATION

Yeast Torulopsis sphaerica were irradiated with a He-Ne laser (632.8 n m) at 460 or 1150 J/m(2) and incubated for 18 h in fresh medium, after which morphometric analysis was conducted on ultrathin sections. Low irradiation decreased the relative number of mitochondrial profiles pe r section, but increased the mean profile area, relative area of crist ae, and distance between neighboring profiles. High dosage caused oppo site changes. The sum relative area of the chondriome per section rema ined unchanged, so the above shifts could reflect spatial rearrangemen ts of mitochondria. The structural alterations correlated with the fun ctional changes found earlier in the electron transport chain: low dos age enhanced while high dosage attenuated the activity of NADH dehydro genase and cytochrome c oxidase.