Mikroorganismy v testech genotoxicity vzorků životního prostředí

Abstract

This bachelor’s thesis examines the use of microorganisms in genotoxicity testing of environmental samples. Today, the environment is exposed to an ever-increasing number of chemical substances capable of damaging the genetic material of living organisms: causing mutations, inducing cancer, or disrupting fetal development. The detection of such substances is one of the key tasks of modern environmental toxicology. The thesis first defines basic concepts – mutagens, carcinogens, and teratogens are, how they differ from one another, and why their timely identification is important. It then describes the international classification criteria used in regulatory practice, particularly the GHS and CLP systems and the IARC classification. The main part of the thesis consists of a systematic overview of testing methods. The primary focus is on microorganisms as model systems: bacteria (Salmonella typhimurium, Escherichia coli), yeasts (Saccharomyces cerevisiae), and microalgae. For each group, specific tests, their principles, advantages, and limitations are described. In addition, tests on plants and animals are also presented. The conclusion of the thesis addresses the reliability of microbial tests in assessing risk to humans and discusses issues of extrapolation, including biological differences between test organisms and human cells, limitations of metabolic activation using S9 mixture, and the occurrence of false-positive and false-negative results.