Environmental and Molecular Mutagenesis - Legacy Tobacco ...

1989 EMS Abstracts 233
presence of 6-TG . Cells were grown in round bottom 96 well microtiter plates and scored Notes
visually (microscopicall*l- .for evidence of cell growth . Spontaneous mutant frequencies
(MF) for a colony of 9 animals (using duplicate samples taken aprox . 2 weeks apart) gave a
mean of 4 .4 t 5.3/106 cells . The appearance of mutants in peripheral blood after an IF dose
of 100 mg/kg ENU was followed in a single animal by sampling weekly for 9 weeks . MFs
for weeks 2-9 were (respectively) 15 .3, 5 .0,16 .5, 9 .9, 20 .6,12 .9,19 .6, and 26.9/106 ;day 0 MF
was 7 .1/106 cells . In general, both MF and cloning efficiency for given animals were
reproducible from sample to sam le . TG resistant clones from all experiments are
currently undergoing molecular analysis to determine the nature of the mutations giving
rise to TG resistant clones in-cynomoiogoas monkeys .
677
AN INSIGHT INTO THE MECHANISMS DETERMINING THE INDUCTION OF GENETIC EFFECTS BY NTA IN
THE MOUSE AND DROSOPHILA SOMATIC AND GERM CELLS .
M . Zordanl, A . Russo', R . Costal, C . Beltra .el, F . Pacchierotti=, M . Ostil and A .G .
Levis' . 1 Dept . of Biology, University of Padova (ITALY) . 2 Lab . Toxicology, ENEA,
CRE Casaccia ROME (ITALY) .
Recently we reported the ability of nitrilotriacetic acid (NTA) to induce
aneuploidy in the germ cells of both Drosophila and the souse . These results prompted
further research in order to evaluate the response to treatment with NTA of somatic
cells in the same organisms . The experimental systems adopted consisted in : a)
chromosomal counting in souse bone sarrow cells after i .p treatment with 138 or 275
eg/Kg NTA ; b) evaluation of single and twin spots in the somatic recor,bint .tion and
mutation test (SMART) in Drosophila selanosaster employing the &w_b e.nd (j=3 wing
∎arkers, after feeding different doses of NTA (Sx10-3, 2 .5x10-2 , Sx10-2 K) for 42
hrs . to 2nd stage larvae . In the latter case effectively absorbed doses of NTA were
also evaluated by a .ethod employing 3H-leucine additioned to the treatr.ent sedts .
The results indicate that NTA does not induce aneuploidy or sister chromatid
exchanges in souse somatic cells . Positive results were obtained ir .utead :n the SMART
test (statistically significant dose-dependent increase in the frepuen .:y ui small
single p_wZi spots) . Extension of the wing spot analysis to include phenotypically AU
individuals (inversion heterozygotes) revealed that small single spots are virtually
absent in these flies following treatment with NTA, suggestiug that in the normal
"w , flrs trans heterozygotes tbese spots originate mainly (90% or more) from
recosbinational events .
SUPPORTED BY C .N .R . p .f . "ONCOLOGIA" .
A
678 Due to late receipt, abstracts 678-697 are presented out of alphabetical order .
CURRENT STATUS OF THE GENE-TOX PROGRAM, Angela Auletta, Office of
Toxic Substance, U .S . EPA, Washington, D .C . 20460 .
The EPA's Gene-Tox Program is a multi-phased effort to review and
evaluate published literature in genetic toxicology . Phase I was a
review by expert work groups of literature published from 1969-1980
for 23 days . Each group published an evaluation of chemicals tested,
correlation of results with carcinogenicity, recommended protocols and
techniques for data analysis, interpretation and presentation . In
1980-81, a computerized data base of over 2,600 chemicals was
established ; this data base was analyzed by individuals concerned with
chemical classification, carcinogenicity, and heritable mutation . At
present, work groups are evaluating literature published since 1980
for selected systems . As the update proceeds, the existing data base
is reanalyzed . Analysis of the data base is affected by several
factors . The preponderance of results are either positive or
inconclusive . The high percentage of inconclusive results largely
reflects the quality of the available literature . Most agents have
been tested in only one system making cross system comparisons
difficult . Correlations with carcinogenicity are hampered by the
nature of the chemicals evaluated and the limited number of validly
tested noncarcinogens in the data base . The data base is publicly
available through the NLM TOXNET system . Public availability should
increase its utility, expand the analysis and affect the manner and
speed with which it is updated .
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679
OD ~
DIET AS A SOURCE OF MUTAGENESIS t0
P .S . Chauhan, Molecular Biology i Agriculture Division, Bhabha Atomic Research Centre,
Trombay, Bombay-400 085 (INDIA) w
Diet is a complex mixture of a large number of chemicals of diverse nature and ~
continues to remain a major source of human ex posure to exogenous chemicals . In ad- v
dition to life support constituents, human diet contains a large number of chemicals
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