A Study on Damage of Chromosomes Activity in Seedlings of Crepis Capillaris - Progress in Organic and Physical Chemistry: Structures and Mechanisms - page 274

frequency rearrangements not found. All the rearrangements were chromatid type.
The authors explain this phenomenon of the formation of secondary mutagens in
cells. Thusly, these experiments [19-21] were showing that mutagens do not cause
aberrations of chromosomes before or after phases of the mitotic cycle G2, G1,
and causes only chromatid aberrations effecting on the chromosomes in the course
of DNA synthesis. Modern microscopy suggests that mutagen penetrating into the
cell is remaining in “space around a chromosome” [22]) in bonding with proteins
or DNA, but its effect is revealing when mutagen passes through phase of DNA
synthesis and becomes discovered in the form of chromosome rearrangements dur-
ing mitosis. The same can be evidence of the phenomenon of fragmentation of
chromosomes, strong destruction of mitosis and the spindle during treatment by
high doses of the alkylating agent (in our case by phosphemid) in culture of ¿ bro-
blasts of human and mouse or in germinal cells of seeds Cr. capillaris . Perhaps the
same principle is working in the course of “chain process” of Dubinin. Someday,
4D microscopy will reveal the mechanism of interaction chromosomes with the
chemical mutagens.
Understanding the mechanism of chemical mutagenesis in the present time is fun-
damentally important in view of the global contamination of the surrounding nature by
different chemicals that damage the genetic structure of organisms.
21.4 CONCLUSION
(1) We have shown that in cultivated fibroblasts phosphemid was suppressing
mitotic index, induces rearrangements of chromosomes.
(2) Inseedlings Crepis capillaris phosphemid also causes inhibition of the mitotic
cycle. The average number of metaphases on the number of nuclei in seedlings
after treatment phosphemid decreased twice.
(3) Phosphemid after treatment of seeds Cr. capillaris causes rearrangements in
the cells of seedlings, regardless of age treated seeds, but depending on the
concentrations of drug. The greatest number of rearrangements occurs when
using the highest concentration of the preparation.
(4) After treatment of the seeds Cr. capillaris by phosphemid were found rear-
rangements only chromatid type in seedlings. The number of rearrangements
of chromosomal type was at the level of controls or smaller. This means that
the preparation works as well as other chemical mutagens, that is chromo-
somes break during DNA synthesis.
(5) Phosphemid in treatment seeds Cr. capillaris showed heterogeneity of ger-
minal cells in the seeds during the G1 phase. The frequency of chromosomal
rearrangements varies depends on the time between fixation and “arising”.
(6) At high concentrations (1 × 1 -2 M ) phosphemid caused the destruction of mi-
totic spindle and multiple fractures of the chromosomes.