Environmental and Molecular Mutagenesis - Legacy Tobacco ...

1989 EMS Abstracts
S . typhimurium TA98 and TA100, with and without metabolic activation . The samples from Notes
the Katsura showed the highest mutagenic activity (3500 revertants with TA98, . +59 ; 87
revertants with TA9B, -S9~ 141 revertants with TA100, +S9 ; negative with TA100, -S9,
per 0 .1-g equivalent of'bIue rayon) . By further measurement at several different sites
of this river, we found that the effluent from a waste-water treatment plant in Kyoto
City is the possible source of the mutagenic pollution . When the samples collected
from this river in the winter and summer of 1988 were fractionated by TLC, the mutagenic
activity in TA98 with metabolic activation was found predominantly in single identical
zones . It is suggested that River Katsura is constantly polluted with certain
frameshift promutagens of polycyclic structures .
490
SALMONELLA MUTAGENICITY TEST ON VARIOUS KIND OF IRRADIATED SUGARS AND AMIlIO ACIDS
K . Sakamoto, K . Kanazashi, S . Iwahara, K .Takatori, and R . Aibara, Hatano Research
Institute, Food and Drug Safety Center, Hadano, [anagawa (Japan)
Recently, various kind of irradiated foods were studied in mutagenicity tests .
Every food comprises variety of components, but the volume of samples that can be
used by these test systems is limited . Accordingly, even if certain components of
the irradiated food should undergo mutagenic changes, it would be impossible to
detect such changes if the volume of them are smaller than the detectable limit of
the test systems .
For this reason, it is necessary to study mutagenicity on each irradiated food
components . And if the test results indicate the formation of mutagens in component
by irradiation, we should evaluate the genetic toxicity of irradiated foods with the
test results in due consideration of : 1) irradiation dose, 2) ratio of mutagenic
products formed from the irradiated food components, 3) strength of mutagenic
activity, 4) proportion of components in food changeable to mutagens and 5) possibility
of elimination of the mutagenic products .
We studied Salmonella/mammalian microsome mutagenicity test on various kinds ofsugars
and amino acids irradiated in the dry condition and in liquid solution with
gamma ray of maximum dosage upto 10 kGy . As a result, weak mutagenic activity was
detected in the 5% solution of cystein and 10% solution of arabinose irradilted at
the maximum dosage of 10 kGy, with metabolic activation system . The results indicate
that the mutagenic products from each compound hardly forms in irradiated foods .
491
CLASTOGENIC EFFECT OF ELLIPTICINE ON DIFFERENT PHASES OF THE CELL CYCLE OF
CULTURED HUMAN LYMPHOCYTES AND ITS SYNERGISTIC ACTION WITH INHIBITORSOF
DNA REPAIR AT G2 . Elza T . Sakamoto-Hojo and Catarina S . Takahashi'(IBILCE-
S . Jose Rio PreEo-UNESP and FFCL de Ribeir`ao Preto-USP, BRASIL) .
Ellipticine, a pyridocarbazole alkaloid, has shown an antitumor effect
on several types of experimental and human tumors, being an intercalating
substance whose mutagenicity has been demonstrated in several systems .
To characterize the mechanism of action of this compound at the cell cycle
level, human lymphocyte cultures from 2 healthy donors were treated with
3 pg/ml ellipticine in 30-minute pulses during different phases of the
cycle and analyzed for chromosome aberrations and sister chromatid exchanges
. The G2 phase was more sensitive in terms of induction of aberrations,
followed by S and G1 . The 24-h treatment (S phase) induced a four
fold increase compared to th8 control . SCE induction was significant only
at G1, when SCE frequency doubled_3The effect of lymphocytg post-treatment
with inhibitors of DNA repair (10 M caffeine and 5 x 10 M 1-B-D-arabino
furanosylcytosine) was also tested by adding 3 yg/ml ellipticine at G in
30-minute pulses and the inhibitors immediately afterward during the2last
3 h before harvesting the cultures . In the two experiments performed on
blood from the 2 donors there was a moderate effect of chromosome aberration
potentiation (about 2-3 times), i .e ., ellipticine bad a synergistic
effect with both inhibitors in terms of chromosome aberration induction .
492
THE ABSENCE OF PAH HYDROXYLATION ACTIVITY IN TOBACCO CALLUS S9 . M . F . Salamone',
S . Richard', C . J . Gentile', J . M . Gentiles, and D . A . Rokosh', 'Ministry of the
Environment, Toronto, Canada and *Hope College, Holland, Michigan .
Microsomal enzymes (S9) from four week old photosynthetic and nonphotosynthetic
tobacco (Nicotiana tobacum) callus cultures were prepared by two separate laboratories .
The ability of each callus S9 to activate 2-aminofluorene (2AF) and benzo(a)pyrene
(BaP) was then tested with the Ames fluctuation and plate incorporation assays . With
each assay the callus S9 preparations from both laboratories increased the mutagenic
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