1) Introduction to Genetic Toxicology
Origin and history of Genetic Toxicology. Chemical structure and morphological organisation of genetic material. Definition and classification of mutations: Gene mutations: base pair substitutions, insertions, deletions; reversion and suppression of mutations; phenotypic effects of gene mutations. Fluctuation test and spontaneous mutation in bacteria (neo Darwinian theory). Chromosome mutations: structural (chromosomal aberrations) and numerical (aneuploidy, polyploidy).
2) Spontaneous DNA alterations
Mis-incorporation of bases that can arise during DNA replication (mismatch, tautomerization of bases) and “proof-reading” mechanism for correction of errors. Deamination of bases, spontaneous loss of bases and oxidative damage to DNA. Molecular mechanisms of insertion and deletions of bases.
3) Environmental agents which damage DNA
Physical mutagens: Ionizing electromagnetic radiations (X-rays, γ-rays, betatron-synchrotron radiations; Ionizing subatomic particles (alpha particles, beta particles neutrons). Non-ionizing electromagnetic radiations (UV-A, UV-B, UV-C); UV and ozone. Electromagnetic fields (microwaves, HF, ELF etc.). Direct and indirect action of ionizing radiations on DNA and “S-independent” mechanism of induction of chromosomal aberrations. Chemical mutagens: Direct and indirect chemical mutagens (metabolic activation); alkylating agents; environmental pollutants in the cities [car exhaust, sulphur and nitrogen oxides, polycyclic aromatic hydrocarbons (PAH), formaldehyde, asbestos]; Food additives and contaminant of aliments (aflatoxins, ochratoxins nitrosamines, heterocyclic aromatic amines, phenols of vegetal origin, etc); therapeutic agents (mitomycin-C, bleomycin, nitrogen mustards, inhibitors of DNA topoisomerases I and II, cytostatic agents); pesticides. “S-dependent” mechanism of chemical mutagens. Biological mutagens: microbial and viral pathogens; transposable elements.
4) Systems of defence and cell response to DNA damage
Antioxidant and non-antioxidant systems of defence (superoxide dismutase, catalase, peroxidase, α- tocopherol, vitamin-C, carotenoids, flavonoids, polyphenols etc). Detoxification systems of xenobiotics: (phase I and phase II enzymes); DNA repair systems: fotoliase, alchiltransferases, “nucleotide excision repair” (NER), “base excision repair (BER), “mismatch repair” (MMR), “SOS” repair, recombinational repair: repair of DNA single strand breaks (SSB) and DNA double strand breaks (HR e NHEJR); DNA damage, activation of cellular “checkpoints, restoration of wild type condition, induction of mutation, apoptosis and genomic instability.
5) Phenotipic effects of somatic and germinal mutations
Mutation and cancer (activation of proto-oncogenes and deactivation of tumor suppressor genes); Mutation and cellular aging; Mutations and genetic diseases (Down, Klinefelter, Edwards, Xeroderma pigmentosum, Ataxia telangiectasia, Bloom syndromes).
6) Assays for detection of genotoxicity
In vitro short-term mutagenicity tests: Gene mutation assay in bacteria(Salmonella typhimurium reversion assay in or Ames test); Gene mutation assay in mammalian cells (loci HPRT or TK+/-); Cytogenetic tests in mammalian cells (chromosomal aberrations, sister chromatid exchanges, micronuclei). In vivo short-term mutagenicity assays: Test of chromosome mutation in somatic cells (analyses of cells in metaphase); micronucleus test in bone marrow erythrocytes of rodents; Comet assay; Unscheduled DNA synthesis (UDS).
7) Biomonitoring of human populations
Biomarkers of exposure (mutagenic activity of mutagens or their metabolites in the urines; determination of chemical adducts to proteins or DNA); Biomarkers of effects: cytogenetics changes (chromosome aberrations, micronuclei, aneuploidy) in peripheral blood lymphocytes or cells of buccal mucosa; Biomarkers of susceptibility: differential DNA repair capability among different individuals; polymorfism of metabolic enzymes.
 
8) Evaluation and regulation of mutagenic risk
Testing strategies and prediction of somatic effects (cancer, genetic diseases) following exposure to genotoxic agents; Food safety and strategies for risk assessment; identification of threshold values of exposure; regulatory aspects.

9) Practise exercise (obligatory):
Evaluation of mutagenic compounds (selected by students) in the following mutagenicity assays:
• Cytogenetic analyses of chromosome aberrations, sister chromatid exchanges (SCE’s) and micronuclei in mammalian cells in vitro;
• Analyses of DNA breakage in human lymphocytes by the alkaline “Comet assay”.

L. Migliore “Genomica e Mutagenesi Ambientale”

Additional books (Available in the university library):
A.P. LI “Genetic Toxicology”
D.H. Phillips and S. Venitt “Environmental Mutagenesis”
R.H. Burdon “Genes and Environment”