Environmental and Molecular Mutagenesis - Legacy Tobacco ...

36 1989 EMS Abstracts 98
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
Notes MUTANTS DEFECTIVE IN POLY(ADP-RIBOSE) NETABOLISN EXHIBIT DIVERGENT PATTERNS IN
SUSCEPTIBILITY TOWARDS DIFFERENT DNA DAMAGING AGENTS . S . Chatterjee, N .F . Cheng,
S .J . Berger and N .A . Berger, Ireland Cancer Center, Case Western Reserve University,
Cleveland, Ohio 44106 .
We have developed two groups of mutant cell lines from V79 Chinese hamster cells
capable of proliferating with impaired poly(ADP-rtbose) metabolism . One group
consists of ADPRT 54 and ADPRT 351 which are defective in poly(ADP-ribose)
polymerase activity while the other consists of N2, N3 and N4 which can grow stably
in the absence of free nicotinamide in the mediun with total NAD levels of 1 .5 -
3 .0% of that found in parental V79 cells grown in camplete medium . Thus, in the
latter group of cells, poly(ADP- N bose) synthesis is restricted due to limited
availability of the substrate MAD . Since poly(ADP-ribose) polymerase has been
implicated in DNA repair we examined the susceptibility of these mutants towards
various kinds of DNA damaging agents and topoisomerase II inhibitors . Our studies
show that these mutants are resistant to topoisomerase II targeted drugs such as
VP-16 and m-ANSA. In contrast, these mutants showed increased sensitivity to NNNG,
bleomycin and X-rays . Preliminary studies show that ADPRT 351 cells repair X-ray
induced DNA strand breaks more slowly than do V79 cells . This phenomenon could
account for their increased sensitivity to X-rays . A detailed account of the
susceptibility of the mutants and Y79 ce11s towards a variety of DNA damaging agents
and possible role of poly(ADP-ribose) polymerase in DNA repair will be presented .
MJhDCZ7iAR ANALYSIS OF HPRT MUTATICNS 3N Y79 CRINESE HAMSTFR CEL1S
M. A . Chaudhry and Margaret Fbx, Paterson Institute for Cancer Research,
Nanchester, M20 .9BX .
To understand basic mectusnisms of mutation at the HPRT locus in Chinese
hamster cells, spontaneous, Xray, MM14 and (F74S) nutants have been independently
isolated . 9 Spontaneous, 36 MMS, 20 Xray, and 20 IIdS mutants were analysed by
Southern blotting and more limited number Northern analysis . None of the
spontaneous mutants showed changes detectable by Southern analysis . 14/36 M
induced, 9/20 Xray induced, and 0/20 FMS induced mutants showed oomplete deletion
of HPRT DNm sequences . The remainder showed no detectable changes . Northern
analysis of the 9 spontaneous mutants indicated 6/9 produced no detectable HPT .T
mRNA,, also in 3/7 MMS induced mutants no mFM was detectable . In a further two MNS
induced mutants the level of niessage was much reduced oaipared with wild-type
levels as indicated by similar levels of APRT message in all cell lines . sJmA frae
further 14 induced mutants was analysed by dot blotting and was much reduced in one
Xray and absent in one Eti4 induced mutant . HPRT mRNn frae 14 mutants has been
amplified using the polymarase chain reaction . In three mutants in which sTM was
undetectable on Northern analysis low levels were detectable after in vitro
amplification . To date the site of the nutatien has been identified by direct UNA
sequencing in four of these mutants . The sutations ware oonsistent with the
lmowm mechanism of action of the autagens . The high proportion of deletions
produced by Xrays and MPiS probably explains their inefficiency as mutagens .
100
LONG-DISTANCE TRANSPORTATION AND RAPID PROPAGATION TECHNIQUE FOR PLANTS
OF TRADESCANTIA PALUDOSA
Kui-2hang Chen and Gui-Ying Peng . Guangxi Institute of Botany,
Yanshan, Guilin, Guangxij PEOPLE'S REPUBLIC OF CHINA
Tradescantia Micznnucleus (Trad-DLS1) Assay, established by Dr . Te-Hsiu Ma, is a
well lnown, simple and effective technique for monitoring mutagens in the envirocment .
Sinoe it was introduoed into China in 1980, it has been used for in situ monitoring
of many sites . In 1986, it was registered in the regulation of Erniir+amental Matiitoring
Technology by the State Environrental Protection Bureau of China . Because
Tradesoantia clone 03 can be repraiuoed only with vegetative propagation, the longdistance
transportation of plants would be a barrier to increasing the appli,ed range .
To overoome these difficulties and keep plants living during lang-distanoe transportation
and to obtain a large number of plants with the same original micronucleus
rate in the pollen mother cells in short time assay, a series of experimsnts have
been doee . These show that selecting a plant whose pollen mother cells oontain low
original micronucleus rate and adopt3ng rapid propagation methods of the test tube
plants , the white buds are suitable for long-distance transportation
99
101
A PRACTICAL TECHNIQUE FOR SHIPPING AND RAPID PROPAGATION OF TRADESCANTIA PLANTS UNDER
POLLUTION-FREE CONDITION, Rulshaaa C_I1gG* and Guiying Peng*, Guangxi Institute of
botany, Yanshan, Guilin, PRO (Introd . by T . H . Na) Departsent of Biological Sciences,
Western Illinois University, Haoosb, IL (USA)
50869 3548