Journal of Lipid Research, Vol 37, 1207-1212, Copyright © 1996 by Lipid Research, Inc.
Age-related changes in neutral lipid content of Paramecium primaurelia as revealed by nile red
P Ramoino, E Margallo and G Nicolo
Institute of Zoology, University of Genoa, Italy.
Cellular neutral lipid content of Paramecium primaurelia was measured
during culture and clonal life using nile red (9-diethylamino-5H-
benzo[alpha] phenoxazine-5-one), a dye utilized for lipid analysis in both
mammalian cells and in ciliated protozoa. Lipid droplets in P. primaurelia
are concentrated in the anterior pole of the cell; their number is maximum
in early log phase cells and decreases in late log phase cells. The
quantitative determination of neutral lipids was obtained measuring the
fluorescence from the excitation and emission spectra of 480 nm and 540 nm,
respectively. Neutral lipid content decreases linearly during the log phase
of growth while the decline is minimum during the stationary phase. In the
late log phase, the amount is 30% of that of the early log-phase cells.
Though the cell size declines too, cell area and lipid content decreases
are not correlated in the middle log phase, because the maximum lipid
reduction is obtained when the cell size is relatively constant. The
cellular lipid content also changes during the clonal life. Neutral lipids
decrease discontinuously (r = -0.75, P < 0.05) as the fission age
increases. No relationship was found between lipid content and food vacuole
formation during both culture and clonal life.