Environmental and Molecular Mutagenesis - Legacy Tobacco ...

124 1989 EMS Abstracts
Notes 216 and TA100 irrespective of presence and absence of 89 ∎ix . The activity for TA300/
PY0219 was about 10 to 600 times higher than TA100 in the abeence of S9 mix . In the
case of TA98 strains, the order of mutagenic activity was complicated, but TA98/PYG216
or 219 gave generally higher mutagenic activity than TA98 . For example, ratio of mutagenic
activity for TA98/PYG219 to that for TA98 ranged from 245 to 630 (mean :430) for
3 kinds of mono-nitropyrenes, from 6 to 370 (mean : 78) for 8 dinitropyrenes in the
absence of S9 mix . The ratio between TA98/PY0216 and TA98 ranged from 130 to 590 (mean :
350) for 3 nitropyrenes and from 0 .1 to 89 (mean : 18) for 8 dinitropyrenes in the absence
of S9 mix . These results demonstrate clearly the usefulness of theme strains for
the detection of nitroarenes in the environment .
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
MODIFICATION OP SALMONELLA MUTATION TEST AND ITS APPLICATION TO ALKYL HYDRAZINES
H . Natsushita,Jr ., K . Yamamoto, M . Mochizuki, O .Endo, and H . Matsushita, IKyoritsu
College of Pharmacy, Minato-ku, Tokyo (Japan), and National Institute of Public
Health, Minato-ku, Tokyo (Japan) .
356
Many environmental hydrazines are carcinogenic . However, information on their mutagenicity
is few and the mutagenic activity reported 1s generally very low in contrast
of their carcinogenicity . We modified the mutagenicity test procedure mainly on the
pre-culture conditions using Salmonella typhimurium strains TA100 and TA102, and
applied the modified method to the survey of mutagenicity of 12 alkylhydrazines :
four 1,1-dialkylhydrazinea, four 1,2-dlalkylhydrazines and four monoalkylhydrazines
with alkyl group from methyl to butyl . In this method, 10 out of 12 alkylhydrazines
were detected as positive in the strain TA100, and all the 12 hydrazines were positive
in the strain TA102 . Mutagenic activity obtained here were generally stronger
than those reported hitherto . The mutagenic activity was stronger in the absence of
metabolic activation, and the presence of 59 mix reduced remarkably the mutagenic
activity . The inhibition by S9 mix was proved to be due to the capturing of mutagens
by protein of S9, since bovine serum albumin also inhibited the mutagenicity of alkylhydrazines
tested . The procedure developed here is useful in detection of many kinds
of environmental mutagens, and also in elucidating mechamisms of mutagenesis and
carcinogenesis of alkylhydrazines .
COMPARISON OF TWO DIFFERENT PROTOCOLS FOR DETECTION OF CHEMICAL-INDUCED
TRANSFORMATION OF BALB/c-3T3 CELLS . E .J . Matthews, Hazleton Laboratories America,
Inc ., Kensington, Maryland .
In 1983, the NTP furnished this laboratory 55 coded chemicals for testing in a standard
transformation protocol using the A-31, 1-13 BALB/c-3T3 cells . This investiyation
revealed that the standard assay was insensitive : 4 chemicals were active, 6 had
limited evidence of activity, and 45 were inactive . Recently 61 of these chemicals
were retested in a modified protocol : 26 chemicals were active, 6 had limited evidence
of activity, and 20 were inactive . Neither the standard nor the modified protocol
used an exogenous activation system . The enhanced sensitivity of the second
protocol was attributed to several procedural changes . First, the initiat seeding
density was increased from j to 3 .2 x 104 celts/60 mm dish . Second, the treatment
time was reduced from U to 48-hours and treatments were begun dav-2 versus O,av-1
after seeding . Third, the method of measuring chemical cytotoxicity changed from a
standard clonal survival assay employing M wild type (wt) cells to a co-culture
assay using 3 .2 x 104 wt and 100 ouabain-resistant ce11s . Additional assay improvements
will be discussed, including : changing the positive control [3-methylcholanthrene
to benzo(a)pyrene], and an alteration of the method of dosing . Finally, many
NTP chemicals had limited solubility in water . This problem was diminished for many
chemicals by dissolving them in an organic solvent at high concentrations and
diluting them 100-fold into medium supplemented with a SX concentration of Pluronic
F68 (1 .25k w/v) . Investigations were supported by NIEHS Contract N01-ES-65150 .
TRANSFORMATION WITH BALB/c-3T3 CELLS . fv J . Matthews, Hazleton Laboratories America,
Inc ., 5516 Nicholson Lane, Kensington, Maryland .
Chemical-induced transformation of A-31,I-13 BALB/c-3T3 cells was investipated using
a modified procedure . Chemical-induced cytotoxicity was measured using a clonal survival
assay employing co-cultures of 200 ouabain-resistant and 3 .2 x 104 wild type
(wt) cells . The transformation assay used vessels seeded with 3 .2 x 104 wt eells
(DAY 0) and 48 hour chemical treatments were started on Dav-2 . Chemicals with solubility
problems in water were dissolved at high concentrations in an organic solvent
and diluted 100-fold into culture medium supplemented with Pluronic F68 (1 .25k w/v)
50869 3636
357
358