1022-7954/01/3709- $25.00 © 2001
Russian Journal of Genetics, Vol. 37, No. 9, 2001, pp. 1094–1095. Translated from Genetika, Vol. 37, No. 9, 2001, pp. 1304–1306.
Original Russian Text Copyright © 2001 by Zainullin, Moskalev.
Studies of the anthropogenic effect on biological
systems is among the most urgent problems of modern
biology. Chronic low-dose irradiation is considered as
one of the most important effects of environmental pol-
lution. Although unable to cause somatic death of the
organism, exposure to a low-intensity radiation modi-
ﬁes various processes in cells and tissues, which even-
tually changes such a complex parameter as life span.
According to current views, genetic instability and
changes in apoptosis play a particular role in aging. In
addition, both these factors are known to change after
exposure to low-dose
-irradiation. Hence, it is possible
to assume that genome instability and apoptosis are
involved in the mechanisms of radiation-induced aging.
The objective of this work was to study the life span
exposed to chronic
low-dose ionizing radiation. We established the dynam-
ics of adult mortality in genotypically different labora-
tory strains of
Analysis of the results
obtained was based on the assumption that, with the
genome destabilized, the reaction of the organism to a
stress factor varies from hormesis to death .
We used three wild-type (Canton S, GB-39, and
Oregon R) and four mutant laboratory
Wild-type laboratory strain GB-39 was kindly pro-
vided by V.A. Gvozdev (Institute of Molecular Genet-
ics, Moscow) and was maintained in mass culture.
Wild-type laboratory strains Canton S and Oregon R
were also maintained in mass cultures. Line
defective in postreplication repair and meiotic recombi-
nation and displays genetic instability . Line
carries several mutant genes on chromosome 3 and has
ru h th st cu sr e Pr ca/TM6B, Bri.
It is of par-
ticular interest that this strain is defective in the
which codes for a protein consisting of 438 amino acid
residues and inhibiting apoptosis in
. In addition, we used two
carrying mutant alleles of the
. These strains are char-
acterized by disturbed development and a higher sensi-
tivity to induction of apoptosis [4, 5]. The
were obtained from Umea Stock Center (Sweden).
All strains were maintained at 25
C with a 12-hour
light period. Irradiation was continued until eclosion of
adults, absorbed dose was 0.6–0.8 Gy per generation.
Irradiation was carried out with the use of
In our experiments, all strains were maintained on a
complete yeast medium until eclosion. Then ﬂies were
anesthesized, males were selected and transferred onto
a sugar–agar medium smeared with yeast suspension.
Once a week, living ﬂies were transferred onto a fresh
medium without anesthesia. The life span was com-
pared in ﬂies of the same age. Dead ﬂies were scored
daily in exposed and nonexposed populations.
Since the life-span frequency distribution is other
than normal, nonparametric statistic methods were
used to compare the life span between test and control
ﬂies, including Kolmogorov–Smirnov, log-rank, and
Experiments showed that low-dose irradiation sig-
< 0.05) increased the life span in wild-type
strains Canton S, Oregon R, and GB-39 (table). In the
strain, irradiation reduced the life span of ﬂies
compared with intact ﬂies of the same strain (
This was also observed with the
0.05). A reduction in life span of
observed for both the
Thus, our data demonstrate that life span increases
in the wild-type strains and decreases in the mutant
strains. The difference in response to irradiation sug-
gests a role of genetic alterations in induced and natural
aging of the organism.
An increase in life span of wild-type ﬂies can be
attributed to activation of the repair systems and other
mechanisms of recovery. As a result of the activation,
cells are better protected against damage and can efﬁ-
ciently eliminate not only existing lesions, but newly
Radiation-Induced Changes in the Life Span
V. G. Zainullin
and A. A. Moskalev
Syktyvkar State University, Syktyvkar, 167001 Russia; e-mail: email@example.com
Institute of Biology, Ural Research Center, Russian Academy of Sciences, Syktyvkar, 167982 Russia
Received March 12, 2001
—Chronic irradiation (accumulated dose 0.6–0.8 Gy) was shown to change the life span in male
Death was retarded in wild-type strains and accelerated in mutant strains defective
in DNA repair and displaying a higher sensitivity to induction of apoptosis.