Environmental and Molecular Mutagenesis - Legacy Tobacco ...

1989 EMS Abstracts
normal gene product, and would result in an altered phenotype when occurrirg as a Notes
heterozygote . Comparative mutagenicity data in the mouse are available for four
genetic endpoints in which recovered mutations are genetically confirmed : recessive
mutations at seven specific loci, dominant cataract alleles, enzyme electrophoretic
variants and enzyme activity alleles . Results indicate the mutation rate to be an
order of magnitude higher for those genetic endpoints which screen for loss events
than for those genetic endpoints which screen for altered gene products . Further, the
ratio gain/loss mutational yield is increased for ENU mutagenic treatment as compared
to radiation, which is due to a shift in the spectrum of DNA alterations to point
mutations as compared to mainly deletions by radiation . Thus, the observed
sensitivity to mutation induction is dependent upon the type of mutational event
screened as well as the type of mutagenic treatment employed .
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THE ROLE OF PHOTOSYNTHESIS IN PROMUTAGEN ACTIVATION BY PLANT SYSTEMS . G . Fedorvicz,
J . Day, G . J . Gentile and J . M . Gentile . Hope College, Holland, MI ., 49423 (USA) .
We investigated the ability of photosynthetic and non-photosynthetic cotton
suspension cell cultures for the ability to activate 2-aminofluorine (2AF) and a
contaminant of 4-nitro-o-phenylenediamine (NOPX) into forms mutagenic to Salmonella
tyhpimurium using the plant cell/microbe coincubation assay . The activation potential
of each cell line was compared under varying light conditions both in the presence and
absence of a potent inhibitor of photosynthesis (3-(3,4-dichlorophenyl)-1,1-demethylurea
(DCMU) and as a function of the plant-cell growth cycle . NOPX was activated
to the same degree by both cell lines under both light and dark regimes, and late-log
phase cultures proved most effective for activation . DCMU, which is not mutagenic to
Salmonella, had no effect on NOPX activation by either cell line under any test
conditions . Experiments with 2AF indicated that this compound was preferentially
activated by non-photosynthetic cells which were harvested from early to mid-logphase
of growth, independent of DCMU treatment . In general, photosynthetic cells
proved non-responsive under all treatment conditions . We are continuing to intestigate
the activation potential of our photosynthetic cell line under more stringent
photosynthetic-inhibitory conditions . If is feasible that calls which are actively
photosynthesizing, or cells that maintain an intact photosynthetic apparatus, may
not rely on certain enzymes complexes for general metabolic functions (e .g .,P450related
enzymes) . Therefore, substrates which require such enzyme complexes for
activation (2AF) would not be metabolized while substrate+e which require other enzyme
complexes (NOPX) would be activated by these cells . Support from NSF Grt .BB5-8712566 .
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MUTAGENICITY OF BURNT GUN PROPELLANTS. J.S . Felton, P. Lewis, M .G . Knize,
and G . Millerl, Biomedical Sciences Division and lHazards Control Dept ., Lawrence Livermore
National Laboratory, P .O . Box 5507, Livermore, CA 94550 .
The use of the Ames/Salmonella assay as a workplace monitoring method is a long-standingpractxx at
LLNL. This practice has led to the discovery of very mutagenic soot in and around a 4 inch test gu
Examination of a rag used to clean the barrel of the gun revealed 87,000 TA98 (+S9) revertants/30 cm~
of the cloth. Analysis of the residue in the gun breech after fuing 2140 g HPC95 and 34 g H870
propellants showed 24 x 106 rev/g residue . Open-air burning of HPC95, H870, M-1, and M-6
propellants (all of which are not mutagenic before burning) gave 3800, 3500,16,600, and 5700 revhng
(-S9) of residue . The presence of S9 reduced the response by -50% . Samples from cloth2ttsed to clean a
22 caliber pistol and rifle and a 12 gauge shotgun showed 289, 1494, and 2375 rev/6 cm (TA98, +S9),
respectively . Two S9 requiring and 1 direct acting mutagenic components have been separated by
HPLC . Subsequent mass spectral anal sis and NMR analysis have not given additional structural
information due to small amounts of purified material available after the final clean-up . Estimated specific
mutagenic activity is >100,000 rev/µg . Chromatographic behavior and specific Ames/Salmoneila
response in TA98 suggest aromatic amutes are responsible for the mutagenic activity . It appears that the
propellant components, nitrocellulose, nitroglycerine, diphenylamine, potassium nitrate, phthalates, and
graphite (present in various concentrations), when heated may produce nitroarornatics in the open-air
burning and aromatic amines in the reduced atmosphere of the guns ; not unlike production of potent
mutagenic aromatics from diesel exhaust and cooked meat . (Work done under auspices of the U .S.DOE
by LLNL under contract No . W-7405-ENG-48) .
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THE CYTOKINESIS-BLOCK MICRONUCLEUS ASSAY : BIOLOGICAL DOSIMETRY IN CANCER PATIENTS
FOLLOWING IN VIVO FRACTIONATED EXPOSURE TO IONISING RADIATION . Fenech M .*, Denham J .**
Francis W .** and Morley A .A .*** . *Bianedicine and Health Prog ., Australian Nuclear
Science and Technology Organisation, New Illawara Rd, Lucas Heights, NSW, Australia ;
**Dept . of Radiotherapy, Royal Adelaide Hospital, Nth . Terrace, Adelaide, SA,
Australia ; *** Dept . of Haematology, Flinders Med . Centre, Bedford Park, SA, Australia .
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
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