Objetivo The objectives are:(i) to evaluate the intrasanguineous Host-Mediated Assay methodology for its usefulness as a short-term in vivo procedure for the monitoring of genotoxic factors;(ii) to optimise this assay by using multi-purpose bacteria and analysing a battery of different genetic endpoints (differential DNA repair effects, mutagenic effects, and mutational specificities);(iii) to compare different genetic targets (laci, supF, lacZ) for mutational spectrometry studies.An important reservation in evaluating the results of bacterial mutagenecity assays (as well as for other genotoxicity assays in vitro) is the uncertainty as to whether the mammalian liver homogenates employed are representative of the magnitude of the activation/deactivation capacity of this organ in the living animals. The Host-Mediated Assay (HMA) has shown to be a useful procedure in dealing with this problem. The introduction of differential DNA repair as an additional genetic endpoint in the intrasanguineous Host-Mediated Assay has extended to extrahepatic tissues the range of organs available for genotoxic studies, in particular the spleen, the lungs, the kidneys and the blood stream. In these latter organs, the recovery of indicator bacteria (a mixture of DNA repair-deficient and repair-proficient E.coli K-12 derivates) is too low for the accurate determination of gene mutation frequencies, but quite sufficient for performing differential survival measurements.The genetic target most widely used in mutational spectrometry analyses is the laci gene of E.coli. The laci is on a F' episome to facilitate the genetic analyses of mutations and recombinational transfer of the laci mutations for DNA sequencing. In this project, further development of rapid methodologies for direct PCR and spectrum analysis of laci mutations will be carried out. The E.coli tyrosine amber suppressor gene, supF, is a highly sensitive and small genetic marker for mutagenesis studies. The supF is a genetic target vulnerable to selectable mutations by very different criteria than those (such as laci) that govern protein-encoding sequences. The supF gene is on multicopy shuttle vector plasmids and has been used traditionally for mutation spectra analyses in mammalian cells. In this project, the supF gene will be evaluated as a genetic target in bacterial studies, thus enabling the comparison of prokaryotic and eukaryotic mutation spectra. The third genetic test to be used in the mutational spectrometry analyses will be the lacZ' alpha complementation assay in ssDNA. Single stranded vectors offer the great advantage of permitting an unambiguous determination of the nature of the base that gives rise to a mutation.The project intends to bridge the methodological gap between the different approaches described above: (i) the comparison of in vivo and in vitro results will validate the aminal-mediated assay as a rapid in vivo technique, (ii) the comparison of chromosomal and vector genetic targets will validate the vector system as a model for repair and mutagenesis of chromosomal DNA, (iii) the comparison of different forward-mutation targets in bacteria will validate them as representative of mutational spectra in mammalian cells. Ámbito científico natural sciencesbiological sciencesmicrobiologybacteriologynatural sciencesbiological sciencesgeneticsDNAnatural sciencesbiological sciencesgeneticsmutation Programa(s) FP3-ENV 1C - Specific research and technological development programme (EEC) in the field of the environment, 1990-1994 Tema(s) 040204 - Risks to health and the environment from chemical substances Convocatoria de propuestas Data not available Régimen de financiación CSC - Cost-sharing contracts Coordinador UNIVERSIDAD DE CORDOBA Aportación de la UE Sin datos Dirección S/N,Avenida Menéndez Pidal S/N 14080 CORDOBA España Ver en el mapa Coste total Sin datos Participantes (3) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo INSTITUTO NAZIONALE PER LA RICERCA SUL CANCRO Italia Aportación de la UE Sin datos Dirección Largo Rosanna Benzi 10 16132 GENOVA Ver en el mapa Coste total Sin datos NATIONAL INSTITUTE OF PUBLIC HEALTH AND ENVIRONMENT Países Bajos Aportación de la UE Sin datos Dirección 9,Antonie van Leeuwenhoeklaan 9 3720 BA BILTHOVEN Ver en el mapa Coste total Sin datos Samtmy Assessment AB Suecia Aportación de la UE Sin datos Dirección 151 85 Södertälje Ver en el mapa Coste total Sin datos
