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Mutational response of mouse spermatozoa to methyl methanesulphonate
200
4TH ANNUAL MI-ETING, HEIDELBERG
Our knowledge to date on aberration induction in mammalian spermatogenesi> is predominantly based on effects indirectly observed during the analysis of meiotic divisions. Recently, improved preparation techniques have resulted in a sufficient score of spermatogonial mitoses. This offers the possibility of acuiring direct information on the kinetics of induced aberrations in the germinal epithelium. NMRI mice as well as Chinese hamsters (4 to o weeks old) received single doses of IOO, 3o0 and 6oo R of X-rays. The irradiated animals and controls were killed ze, 24 and 48 h after treatment, tim testes removed and preparations of .N)ermatog~mial mitoses made by the air-drying method. In view of the rate of cell damage, the specie., were compared aa to their sensb tivity against irradiation. The various forms of aberration observed will be discussed.
19 SAvI¢ovId N., J. PEI2EVSKI AND *A. DJELINEO,Institute of Nuclear Sciences "Boris KidriU', Radiobiological Laboratory, and *Pharmaceutical Industry "Galenika", Belgrade (Yugoslavia).
Cytogenetic analysis of meiotic chromosomes of irradiated mice and their progeny after treatment with streptomycin and dihydrodeoxystreptomycin The purpose of this investigation was to find out whether streptomycin and tile related compound dihydrodeoxystreptomycin have any mutagenic effect and whether they are capable of reinstating X-ray-induced chromosomal translocations in mouse spermatogonia of directly treated animals and their first generation progeny. Male C3H mice were divided into 3 groups: (z) only irradiated with 60o R; (e) irradiated and treated with streptomycin and dihydrodeoxystreptomycin ; and (3) treated with streptomycin and dihydrodeoxystreptomycin without irradiation. All animals were injected s.c. with a daily dose of o.o2 mg/g nody weight initially, with subsequent increase, hnmediately after treatment, each male was mated with normal females. The offspring obtained from these treated males were examined cytologically 12 weeks after birth. There was no mutagenic effect in animals treated with streptomycin and dihydrodeoxystreptomycin without irradiation. The frequency of chromosomal translocations after total irradiation was 9.O7°o . Treatment with streptomycin and dihydrodeoxystreptomycin after irradiation significantly decreased the percentage of chromosome rearrangements. The frequency of chrolnosonm rearrangements in the group treated with streptomycin after exposure was 5.13°o: and it was 3.7o°,~ in animals that were treated with dihydrodeoxystreptomycin. Male offspring originating from parents treated only with antibiotics showed no chronmsomal translocations. However, offspring originating from irradiated and treated parents gave birth to male offspring with chromosomal translocations.
2O
J.,, AND J. H. SCHR{SDER a, Institute of Zoology, University of Im>bruck, Innsbruck (Austria) 1,* and Institute of Biology, Association for Radiation and Environmental Research, Neuherberg/Mfinchen (West Germany) ~. SCHIECHTL,
EUROPEAN
ENVIRONMENTAL MUTAGEN SOCIETY
207
Mutational response of mouse spermatozoa to methyl methanesulphonate After intraperitoneal injection of 5° mg of methyl methanesulphonate (MMS) per kg body weight, tabby male mice were mated to non-treated C3H inbred females for one week. By this means the mutational response of mouse spermatozoa was tested. Sham-treated tabby males and their offspring were handled in the same manner and served as controls. The Fz mice were outcrossed with IOI inbred mice to produce an outcross generation. In a search for induced recessive mutations, each Fz female was back-crossed with all her sons and each Fz male was backcrossed with all his daughters according to Lt"NING'S schedule. The aggressive activity of the Fz and back-cross generation males was determined for each by the use of a transparent tube. A 25~o decrease of the mean litter size was found in Fz after MMS treatment. The F1 sex ratio was not affected. In the Fz × ioz out-ceoss generation, however, the percentage of males increased significantly in the MMS group as compared with the corresponding controls. The mean litter size was reduced by z6% in the MMS group. Neither the litter size nor the frequency of males was changed significantly in the back-cross generation. The intensity of aggressive actions was 40.54 ± 4.59 for the F1 males of the MMS group and 29.06 ~ 2.99 for the Fz males of the controls. No consistent differences were found between the aggressiveness of the two groups in the back-cross generation.
4TH ANNUAL MI-ETING, HEIDELBERG
Our knowledge to date on aberration induction in mammalian spermatogenesi> is predominantly based on effects indirectly observed during the analysis of meiotic divisions. Recently, improved preparation techniques have resulted in a sufficient score of spermatogonial mitoses. This offers the possibility of acuiring direct information on the kinetics of induced aberrations in the germinal epithelium. NMRI mice as well as Chinese hamsters (4 to o weeks old) received single doses of IOO, 3o0 and 6oo R of X-rays. The irradiated animals and controls were killed ze, 24 and 48 h after treatment, tim testes removed and preparations of .N)ermatog~mial mitoses made by the air-drying method. In view of the rate of cell damage, the specie., were compared aa to their sensb tivity against irradiation. The various forms of aberration observed will be discussed.
19 SAvI¢ovId N., J. PEI2EVSKI AND *A. DJELINEO,Institute of Nuclear Sciences "Boris KidriU', Radiobiological Laboratory, and *Pharmaceutical Industry "Galenika", Belgrade (Yugoslavia).
Cytogenetic analysis of meiotic chromosomes of irradiated mice and their progeny after treatment with streptomycin and dihydrodeoxystreptomycin The purpose of this investigation was to find out whether streptomycin and tile related compound dihydrodeoxystreptomycin have any mutagenic effect and whether they are capable of reinstating X-ray-induced chromosomal translocations in mouse spermatogonia of directly treated animals and their first generation progeny. Male C3H mice were divided into 3 groups: (z) only irradiated with 60o R; (e) irradiated and treated with streptomycin and dihydrodeoxystreptomycin ; and (3) treated with streptomycin and dihydrodeoxystreptomycin without irradiation. All animals were injected s.c. with a daily dose of o.o2 mg/g nody weight initially, with subsequent increase, hnmediately after treatment, each male was mated with normal females. The offspring obtained from these treated males were examined cytologically 12 weeks after birth. There was no mutagenic effect in animals treated with streptomycin and dihydrodeoxystreptomycin without irradiation. The frequency of chromosomal translocations after total irradiation was 9.O7°o . Treatment with streptomycin and dihydrodeoxystreptomycin after irradiation significantly decreased the percentage of chromosome rearrangements. The frequency of chrolnosonm rearrangements in the group treated with streptomycin after exposure was 5.13°o: and it was 3.7o°,~ in animals that were treated with dihydrodeoxystreptomycin. Male offspring originating from parents treated only with antibiotics showed no chronmsomal translocations. However, offspring originating from irradiated and treated parents gave birth to male offspring with chromosomal translocations.
2O
J.,, AND J. H. SCHR{SDER a, Institute of Zoology, University of Im>bruck, Innsbruck (Austria) 1,* and Institute of Biology, Association for Radiation and Environmental Research, Neuherberg/Mfinchen (West Germany) ~. SCHIECHTL,
EUROPEAN
ENVIRONMENTAL MUTAGEN SOCIETY
207
Mutational response of mouse spermatozoa to methyl methanesulphonate After intraperitoneal injection of 5° mg of methyl methanesulphonate (MMS) per kg body weight, tabby male mice were mated to non-treated C3H inbred females for one week. By this means the mutational response of mouse spermatozoa was tested. Sham-treated tabby males and their offspring were handled in the same manner and served as controls. The Fz mice were outcrossed with IOI inbred mice to produce an outcross generation. In a search for induced recessive mutations, each Fz female was back-crossed with all her sons and each Fz male was backcrossed with all his daughters according to Lt"NING'S schedule. The aggressive activity of the Fz and back-cross generation males was determined for each by the use of a transparent tube. A 25~o decrease of the mean litter size was found in Fz after MMS treatment. The F1 sex ratio was not affected. In the Fz × ioz out-ceoss generation, however, the percentage of males increased significantly in the MMS group as compared with the corresponding controls. The mean litter size was reduced by z6% in the MMS group. Neither the litter size nor the frequency of males was changed significantly in the back-cross generation. The intensity of aggressive actions was 40.54 ± 4.59 for the F1 males of the MMS group and 29.06 ~ 2.99 for the Fz males of the controls. No consistent differences were found between the aggressiveness of the two groups in the back-cross generation.