ENVIRONMENTAL MUTAGENESIS

The Environmental Mutagenesis course aims to provide knowledge of the mechanisms underlying mutagenesis and genotoxicity induced by environmental chemical and physical agents, as well as of the main experimental approaches used for their assessment.

By the end of the course, students will have achieved the following learning outcomes:

Knowledge and understanding

• know the main environmental mutagenic and genotoxic agents and their mechanisms of action;
• understand the relationships between exposure to genotoxic agents and human diseases;
• know the main mutagenicity and genotoxicity tests and the cytogenetic, molecular, and genomic approaches used in environmental monitoring and human biomonitoring.

Applying knowledge and understanding

• apply the acquired knowledge to the assessment of the genotoxic effects of chemical and physical agents and environmental matrices;
• understand the principles and experimental procedures of the main mutagenicity and genotoxicity tests;
• analyze and interpret the results obtained through cytogenetic and molecular tests.

Making judgements

• critically evaluate the results of the main mutagenicity and genotoxicity tests;
• identify the most appropriate experimental approaches according to the agent or environmental matrix to be analyzed.

Communication skills

• correctly use the scientific terminology of environmental mutagenesis and genotoxicity;
• clearly describe and discuss the principles, methodologies, and results of the main genotoxicity analyses.

Learning skills

• independently expand the acquired knowledge and integrate it with new methodological approaches;
• use the acquired knowledge and skills as a basis for further study in the fields of genetics, genomics, and environmental monitoring.

The course includes:

• lectures covering the theoretical aspects of environmental mutagenesis and genotoxicity;
• exercises and learning activities, including remote laboratory activities, aimed at understanding the main experimental methods for the assessment of genetic damage;
• analysis and interpretation of results obtained from mutagenicity and genotoxicity tests.

Information for students with disabilities and/or specific learning disorders (SLD). In accordance with current legislation and to ensure equal learning opportunities, students requiring accommodations are encouraged to arrange an individual meeting with the course instructor in order to discuss any appropriate compensatory and/or dispensatory measures based on the learning objectives and their specific needs. Students may also contact the departmental CInAP (Centro per l'Integrazione Attiva e Partecipata – Services for Students with Disabilities and Specific Learning Disorders) representative.

Basic knowledge of Genetics and Cytology is required.

In particular, students are expected to have knowledge of:

• structure and organization of genetic material;
• chromosomes and karyotype;
• structure of prokaryotic and eukaryotic cells;
• cell cycle;
• somatic and germ cells.

Students are therefore advised to have already passed an examination in Genetics and an examination in Cytology or equivalent courses.

Attendance is mandatory, as established by the Degree Programme Regulations.

General principles of mutagenesis
Spontaneous and induced mutations. Chemical and physical mutagens. Environmental factors that damage DNA. Mutagenic and promutagenic compounds. Mechanisms of action of mutagenic agents. Metabolism and activation of xenobiotics.

DNA damage and repair systems
Main types of DNA damage. Cellular mechanisms involved in the response to genetic damage. Overview of the main DNA repair systems.

Mutagenesis, carcinogenesis, and human diseases
Effects of exposure to genotoxic agents on human health, with particular reference to carcinogenesis. Genetic basis of carcinogenesis. Proto-oncogenes and oncogenes. Tumor suppressor genes. Genomic alterations involved in neoplastic transformation.

Mutagenicity and genotoxicity tests
Short-term and long-term tests. In vitro and in vivo tests. In vitro tests using microorganisms. Gene mutation tests in bacteria. Forward mutation and reversion. Ames test: general principles and applications. Identification of direct-acting mutagens and promutagenic compounds.

In vitro tests using mammalian cells
Cell cultures and the main cellular systems used in genotoxicity testing. Chinese hamster cell lines. Peripheral blood mononuclear cells. Cellular response to mutagenic agents. Assessment of cytotoxicity in mutagenicity tests.
Gene mutation tests. Cytogenetic tests. Metaphase analysis: chromosomal aberration and sister chromatid exchange (SCE) tests. Classification of the main chromosomal aberrations.
Interphase analysis: micronucleus test. DNA damage analysis: comet assay.

Genomic and molecular analyses
Molecular methods for biomarker assessment and the identification of mutations and genomic alterations. Analysis of copy number variations. Array-CGH and molecular cytogenetic techniques. Overview of genomic sequencing approaches applied to the study of environmental genotoxicity.

Monitoring genotoxicity in environmental matrices
Principles and methods for monitoring genotoxicity in different environmental matrices. Assessment of genotoxicity in air, water, and soil.

Human biomonitoring
Principles of biomonitoring human populations exposed to chemical and physical agents with genotoxic activity. Biomarkers of exposure, effect, and susceptibility. Interpretation of the results of biomonitoring studies.

L. Migliore. Genomica e Mutagenesi Ambientale. Zanichelli, Bologna, 2018.

Teaching materials and lecture slides provided by the instructor.

Assessment Methods

The final examination consists of a written test with two open-ended questions, followed by an oral examination.

The assessment is aimed at evaluating:

• knowledge of the principles of environmental mutagenesis and genotoxicity and understanding of the mechanisms of action of mutagenic agents;
• knowledge of the main mutagenicity and genotoxicity tests and the ability to interpret their results;
• knowledge of the main strategies for monitoring environmental genotoxicity and human biomonitoring.

During the course, intermediate tests on the topics covered and exercises aimed at analyzing and interpreting the results of mutagenicity and genotoxicity tests may be included.

Information for students with disabilities and/or specific learning disorders (SLD): In accordance with current legislation and to ensure equal opportunities, students requiring accommodations may request an individual meeting with the instructor to discuss appropriate compensatory and/or dispensatory measures, consistent with the learning objectives of the course and their specific needs. Students may also contact the departmental representative of CInAP (Centre for Active and Participatory Inclusion – Services for Students with Disabilities and Specific Learning Disorders) for further assistance.

• Spontaneous mutations: DNA polymerase errors.
• Chemical mutagens: classification and mechanisms of action.
• Chemical mutagens: DNA-reactive compounds.
• Xenobiotic metabolism: benzene and polycyclic aromatic hydrocarbons.
• Carcinogenesis: proto-oncogenes and their conversion into oncogenes.
• Carcinogenesis: mechanisms and effects of loss of function of tumor suppressor genes.
• Genotoxicity tests: the Ames test.
• Genotoxicity tests: the chromosomal aberration test.
• Genotoxicity tests: in vitro tests using metabolically competent and non-metabolizing mammalian cells.
• The micronucleus test: principles and applications.
• The comet assay: principles and applications.
• Genomic and molecular analyses applied to the study of environmental genotoxicity.
• Monitoring of air genotoxicity.
• Human biomonitoring: biomarkers of exposure and effect.
• Human biomonitoring: biomarkers of susceptibility.
• Evaluation and interpretation of the results of a genotoxicity test based on chromosomal aberration analysis.
• Evaluation and interpretation of the results of a genotoxicity test based on SCE analysis.
• Evaluation and interpretation of the results of a genotoxicity test based on micronucleus analysis.