Environmental and Molecular Mutagenesis - Legacy Tobacco ...

253 1989 EMS Abstracts
EFFECT OF THE RELATIVE HUMIDITY ON THE FORMATION OF NITROPYRENES BY TME PHOTOCHEMICAL Notes
REACTION OF PYRENE WITH NITROGEN OXIDES
Yoshiharu Hisamatsu, Kazutoshi Sugita, and Hidetsuru Matsushita The Institute of
Public Health, 6-1 Shirokanedai 4-chome Minato-ku Tokyo 108, Japan
The 2-nitropyrene, which have not been identified in direct emissions, in collected
ambient particulate organic matter have been idetified and quantified . We have investigated
the effect of the relative humidity (r .h .) to study the atmospheric transformation
of pyrene to 2-nitropyrene, which is direct-acting mutagen, by the photochemical
reaction with nitrogen dioxide .
The photochemical reaction products of pyrene with nitrogen dioxide under various
humidity of the air which is used to dilute nitrogen dioxide gas were fractionated to
analyze for mononitro-pyrene by HPLC . The partial fractions corresponding to mononitro
pyrene were analyzed using GC-MS, and the molecular ions m/z 247([M]+) together with
the characteristic fragment ions, m/z 217([M-NO]+) and 201([M-N02]+), were monitored .
The 2-nitropyrene has been identified in the photochemical reaction products of
pyrene with nitrogen dioxide below 20% r .h . of air, but it has not been identified
in the reaction products of them under no light irradiation . The photochemical
reaction products were the most mutagenic below 20% r .h . of air for Salmonella typhimurium
strain TA98 in the absence of S9 mix , and the mutagenic activities of them
decreased with the increase of air .
254
DIRECT MEASUREMENT OF CHROMOSOME REPAIR BY PREMATURE CHROMOSOME CONDENSATION .
Walter N . Hittelman . Department of Medical Oncology . University of Texas M . D .
Anderson Cancer Center, Houston, Texas, USA 77030 .
Chromosome damage in interphase cells is generally visualized when the cell
reaches mitosis and the chromosomes condense . However, several events might have
occurred between the time of genetic insult in interphase and chromosome
visualization at mitosis, including repair of chromosome damage and delay of•damaged
cells from reaching mitosis . In addition, chromosome damage in non-dividing call
populations cannot be visualized by conventional techniques due to the lack of
mitoses . The technique of premature chromosome condensation overcomes these
problems by allowing the direct visualization of interphase chromosomes . Thus
chromosome damage and its repair can be directly measured in interphase cells . We
and others have used this approach to better understand . .the underlying basis for
chromosome damage and its repair as well as to characterize repair capabilities of
various radiation and drug-sensitive and resistant cells . For example, chromosome
repair in normal fibroblasts and lymphocytes exhibit a fast and a slow component of
chromosome repair, while mature granulocytes show little chromosome repair . The
fast component can be inhibited by hypertonic salt while the slow component is
inhibited by inhibitors of protein or DNA synthesis . Radiation-sensitive cell lines
such as LS178Y-S and Ataxia telangiectasia exhibit partial deficiencies in both the
fast and slow components of chromosome repair . The ability to directly measure
chromosome repair by the technique of premature chromosome condensation can now be
applied to better understand the in vivo interaction of environmental mutagens with
tissues within the body .
255
THE EBV-Xy1E SMJ111E : ITS OODE'D2111RI0ii MD MJfATIaiAL SPDCIFICITY IN Hu7AN CELL .
X . K. Hong, X. L . Wang,X .F . Qiu and J .L.Hsueh, Institute of Genetics, Fudan University,Sha*si (Qdna)
A n.rber of studies recently have been reported in which shuttle vector plasmids were used to study
mitational specificity in memmalian cells . Shuttle vector systems have becc.re an inportant tool in the study
of nutational mechanisms in higher organisms . We have developed a shuttle vector system for studying mr
tational specificity, as a mutational target, the shuttle vector contains the EB virus origin and E . coli
Xy1E gene, which codes for the enzyme Catechol : oxygen 2,3-oxidoreductase . '!he vector which we constructed
nared pFV891, is derived fram plasmid p1CfA2, pTG503, p'iCfiO'+ and pACi3 . The bacterial gene XylE, carried on
a shuttle vector, is introduced into human cultured cells by transfection and allowed to replicated autonomously
in the cell nucleus . During the replication period of the vector, the cells are exposed to a sut .gan,
an increased in nutation frequency above the spontaneous background is readily obtained . Mitations form in
the shuttle vector DNA in the memrelian rucleus . DNA is extracted and introduced into bacteria . Colonies
that express Xy1E becan; yellow within seconds after selection plates are sprayed with Catechol, while cells
were transformed by the shuttle vector in which the XylE gene were mutated didn't change the colour . Therefore,
induced sutants can be rapidly isolated and characterized . Tne sensitive colour assay offers an approch
to develop this shuttle vector for a wide variety of host organisms . Use of the EBV-Xy1E shuttle vector
should permit determination of the mrtagenic specificity of a wide range of muagens and carcinogens in hr-
rmn cells .
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