Environmental and Molecular Mutagenesis - Legacy Tobacco ...

168 1989 EMS Abstracts
Notes peak olaetog+nj&.tty-seems to be related to the runoff of the pollutants from the upper
atream of:ftlte 0smF1: Five on site monitoring tripe were made at each of the three
locatione, -U e . Conalep, Flores Magon (induetrial sone) Belles Aetee (Downtown) in May
and June, 1988~Positive resulte were obtained in ∎ore than 60% of the tests
conducted .. -~a--r-
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
487
PATTERNS OF MUTATIONAL SENSITIVITY IN POST-STEM-CELL STAGES OF MOUSE
SPERMATOGENESIS AND IN ZYGOTES : 'I'HE GENERATION OF DELETION MUTANTS AND
MOSAICS . Liane B . Russell, Oak Ridge National Laboratory . Oak Ridge, TN. 37831-8077.
Because the majority of conclusive results in the mouse specific-locus test (SLT), are for to#onial
stem cells, we are engaged in enlarging the SLT data base for post-stem-cell stages (from differentiating
spermatogonia to mature spermatozoa), each of which spans a relatively brief time interval . Chemicals differ
markedly in their relative effects on different post-stem-cell stages, both with regard to mutation rate and to
productivity (determined by dominant-lethal incidence and germ-cell death) . Mutations induced by chemicals
that have their greatest mutagenic effect in premeiodc (but post-stem-cell) stages appear to be smaller genetic
lesions than mutations induced by chemicals that are most effective in postmeiottc stages . The correlation
between patterns of germ-cell-stage sensitivity for specific-locus mutations and dominant lethals, which has
been noted for some chemicals, does not hold for others . Of all post-stem-cell mutagens chlorambucil
(CHL) is the mos~ effective : we have shown that exposure of early spermadds to only 10 mg CHIIkg
induces 1 .3 x 10' mutations per locus . Almost all such mutations have proved to be deletions or other
structural changes, which are highly valuable tools for molecular mapping studies . -- The zygote may be
regarded as the final germ-cell stage, since maternal and paternal genomes are still separate . We have found
that ethylnitrosourea (ENU) produces a very high frequency of pritttarily small genetic lesions in zygotes,
most resulting mutants being mosaics. Mosaics can provide very useful biological tools for developmental
studies . Thus . CHL administered to early spermatids, and ENU to zygotes, may be the mutagenic
treatments of choice for generating maximum frequencies of, respectively, large-lesion whole-body mutants
and smaU-lesion mosaic mutants . [Research 'p indy sponsored by the Office of Health and Environmental
Research, U .S . DOE contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc ., and by the
National Institute of Environmental Health Sciences under IAG No . 222Y01-ES-10067 .)
488
DOSE REPETITION GREATLY INCREASES THE MUTAGENIC EFFECTIVENESS OF ENU IN
MOUSE SPERMATOGONIA : ADDITIONAL DATA . W. L . Russell, P. R. Hunsicker, and S . C.
Maddux, Biology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-8077 .
The maximum practicable single dose of ethylnitrosounea (ENU) that can be~g~ven intrapertioneaUy co
mice in mutagenic studies is appro ximately 250 mg/kg . We reported earlier (Hitotsumachi et al ., 1985,
Proc. Natl. Acad. Sci. USA, 82 : 6619-6621) that the effectiveness of ENU in inducing mutations at
specific loci in stem-cell spermatogonia of mice could be increased above the level obtained with 250
mg/kg by using 4 doses of 100 mg/kg spaced at weekly intervals . The increase obtained was 2.2 times,
and was statistically significant (P, one-tailed - 0 .02), even when calculations were adjusted for the
occurrence of clusters . However, since this adjustment is only a rough approxitnadon, and since the
protocol of repeated doses is an attractive one for other investigators desiring a high mutation rate, we
decided to increase our sample size by doing a teplicate experiment . A total of 37 mutations was obtained
in 3428 offspring from treated stem-cell spetmatogonia. Clusters were again uent, but there were at
least 20 independent mutations . The mutadon frequency is almost identical wI that obtained earlier .
Furthermore, the significance of the difference of the combined data from the mutation frequency obtained
with a single dose of 250 mg/kg is now more convincing (P, one-tailed - 0 .003), and the recommendation
to other investigators of rhe value of the dose-repetition protocol can now be made with more confidence .
As was emphasized in our earlier publication, the mutation frequency obtained is of a magnitude that
seemed out of reach a few years ago, being 36 times the highest reported for pr .carbazine, the most
effective chemical mutagen known for stem-cell spermatogonla before ENU had been tested . [Research
jointly sponsored by the Office of Health and Environmental Research, U .S . DOE contract DE-AC05-
840R21400 with Martin Marietta Energy Systems, Inc ., and by the National Institute of Environmental
Health Science under IAG No. 222Y01-ES-10067 .]
489
CONCENTRATION OF MUTAGENIC COMPONENTS IN RIVER WATER BY USE OF THE BLUE RAYON METHOD
Hiroshi Sakamotol, Katsuhiko Nakamuroz Yasuyoshi Sayato2 and Hikoya Hayatsut
F~ulty of Pharmaceutlcal Sciences, Okayama University, Taushima, Okayama 700
2Faculty of Pharmaceutical Sciences, Seteunan University, Hirakata, Osaka 537-01, Japan
Activated carbon and %AD-resin are widely used for concentration of organic mutagens
in river water . In these procedures, a large volume of water has to be taken out of
the river and processed . Use of the blue rayon method gives facilty for concentrating
mutagens with polycyclic structures from river waters . In this method, blue rayon is
allowed to stand for a day in the river to make contact with the flowing water, and
compounds adsorbed to the rayon 1s then eluted and assayed for mutagenicity . In this
way, we have measured the mutagenicity of the water of River Yodo in Osaka, and that of
the tributary rivers Katsura, Kisu and Uji in Kyoto . The mutagenicity is assayed with
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