INCREASE IN THE NUMBER OF ASSOCIATIONS OF ENDOPLASMIC RETICULUM WITH MITOCHONDRIA AND
PLASMA MEMBRANE IN YEAST CELLS STIMULATED TO DIVISION WITH He-Ne LASER LIGHT
V. M. Manteifel, T. I. Kant
Institute of Laser and Informatic Technologies RAS, Troitsk, Moscow Region, Russia;
e-mail: tkaru@isan.troitsk.ru
We studied the ultrastructure of Torulopsis sphaerica yeast cells irradiated with He-Ne laser
(λ = 632.8 nm, dose - 460 J/m2) and then cultured for 6 h in the nutrient with 1 % glucose by aeration. The length of
membranes of endoplasmic reticulum (ER) and the number of its associations with mitochondria (M) and plasma membrane (PM) were
measured on ultrathin sections. A distance of less than 50 nm between heterogeneous membranes was considered as an "association".
The cells from irradiated cultures are characterized by the following features: 1) the length of cortical ER membranes in relation to cellular
perimeter, and. the length of perinuclear ER membranes in relation to nuclear perimeter increase, resp., by 21 and 79 %; 2) the number of
ER-PM associations per cellular section, and that per unit of PM length increase, resp., by 26 and 41 %; 3) the number of ER-M association
in relation to the total mitochondria! perimeter, and to perimitochondrial ER increase by 80 and 87 %, resp. The latter may be associated
with Ca2+ uptake by mitochondria associated with ER, which results in activation of respiration and ATP production.
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