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Mutagenic and recombinogenic action of hydroxylamine on yeast
EUROPEAN
ENVIRONMENTAL
MUTAGEN
23
SOCIETY
taneous levels and no persistent mechanical disturbance of mitoses in root meristems. The exception to this negative generalisation is for mutation or loss of mitochondrial DNA (assayed as mutation to respiratory deficiency in Saccharomyces) which can be effected by heat or peroxides produced by ultrasound irradiations (providing sufficient intensity is applied). Apart from the latter limiting case, it is argued that ultrasound exerts a “bulk” effect upon cellular constituents (and hence little selective effect upon DNA or chromosomes) and is unlikely to yield mutations. It seems very unlikely that current medical diagnostic procedures will give rise to any genetic hazard. This research
was supported
by the Medical
Research
Council
(Great
Britain).
5 BARANOWSKA,
Biophysics,
Mutagenic
H., J. PACHECKA AND A. PUTRAMENT, Institute Polish Academy of Sciences, Warsaw (Poland).
and recombinogenic
action
of hydroxylamine
of Biochemistry
and
on yeast
In yeast, hydroxylamine induces mutations, and intra- and intergenic recombination. However, their frequencies and cell viability show striking variation from experiment to experiment, even when the cell cultures and conditions of mutagen treatment are maximally standardized. There seems to be no definite correlation between mutagen concentration ranging from 0.1 ill to 2 M, and the induction of mutation or recombination. These observations, together with the data on mutagenic and recombinogenic effects of O-methylhydroxylamine, strongly suggest that reaction products between these two mutagens and cytosine play a minor role, if any, in mutation and recombination induction in yeast. The inhibition of respiration and alcohol dehydrogenase activity may be partly responsible for hydroxylamine-induced cell death.
6 BENES,
Prague
Testing
V., R. J. SRAM (Czechoslovakia).
of mutagenicity
AND
R. TUSCAKY,
Institute
of Hygiene
and Epidemiology,
of Fenitrothione
A three-generation study was carried out in rats on the effects of the pesticide of Czechoslovak production, Fenitrothione, belonging to the group of organophosphates (chemical structure, dimethyl-3-methyl-4nitrophenyl phosphorothionate). Fenitrothione, 96%, was administered in the diet, the doses being IO, 40 and 80 p.p.m. A group of control animals received TEPA, the amount being adjusted to 2.5 mg/kg body weight. Frequencies of DL in exposed males and females in each generation and those of chromosomal aberrations in the bone marrow of second generation progeny were used as criteria for measuring genetic damage. Ioo-day-old animals were mated, and two litters were sired in each generation. In a preliminary study the DL frequencies were determined in both the males and females from the second litter of each generation, the exposed males being mated with the unexposed females and the
ENVIRONMENTAL
MUTAGEN
23
SOCIETY
taneous levels and no persistent mechanical disturbance of mitoses in root meristems. The exception to this negative generalisation is for mutation or loss of mitochondrial DNA (assayed as mutation to respiratory deficiency in Saccharomyces) which can be effected by heat or peroxides produced by ultrasound irradiations (providing sufficient intensity is applied). Apart from the latter limiting case, it is argued that ultrasound exerts a “bulk” effect upon cellular constituents (and hence little selective effect upon DNA or chromosomes) and is unlikely to yield mutations. It seems very unlikely that current medical diagnostic procedures will give rise to any genetic hazard. This research
was supported
by the Medical
Research
Council
(Great
Britain).
5 BARANOWSKA,
Biophysics,
Mutagenic
H., J. PACHECKA AND A. PUTRAMENT, Institute Polish Academy of Sciences, Warsaw (Poland).
and recombinogenic
action
of hydroxylamine
of Biochemistry
and
on yeast
In yeast, hydroxylamine induces mutations, and intra- and intergenic recombination. However, their frequencies and cell viability show striking variation from experiment to experiment, even when the cell cultures and conditions of mutagen treatment are maximally standardized. There seems to be no definite correlation between mutagen concentration ranging from 0.1 ill to 2 M, and the induction of mutation or recombination. These observations, together with the data on mutagenic and recombinogenic effects of O-methylhydroxylamine, strongly suggest that reaction products between these two mutagens and cytosine play a minor role, if any, in mutation and recombination induction in yeast. The inhibition of respiration and alcohol dehydrogenase activity may be partly responsible for hydroxylamine-induced cell death.
6 BENES,
Prague
Testing
V., R. J. SRAM (Czechoslovakia).
of mutagenicity
AND
R. TUSCAKY,
Institute
of Hygiene
and Epidemiology,
of Fenitrothione
A three-generation study was carried out in rats on the effects of the pesticide of Czechoslovak production, Fenitrothione, belonging to the group of organophosphates (chemical structure, dimethyl-3-methyl-4nitrophenyl phosphorothionate). Fenitrothione, 96%, was administered in the diet, the doses being IO, 40 and 80 p.p.m. A group of control animals received TEPA, the amount being adjusted to 2.5 mg/kg body weight. Frequencies of DL in exposed males and females in each generation and those of chromosomal aberrations in the bone marrow of second generation progeny were used as criteria for measuring genetic damage. Ioo-day-old animals were mated, and two litters were sired in each generation. In a preliminary study the DL frequencies were determined in both the males and females from the second litter of each generation, the exposed males being mated with the unexposed females and the