1. In vitro gene mutation test: Salmonella typhimurium/lactation microsomal enzyme test (Ames test), mammalian somatic cell strain mutation test 2. Gene mutation test in vivo ◇ Dominant lethal mutation test, Drosophila sex-linked recessive lethal test (SLRL)

1. In vitro/in vivo sister chromatid exchange test (SCE) 2. In vitro/in vivo unprogrammed DNA synthesis test (UDS test)

1. In vitro chromosome aberration test: chromosome aberration analysis of mammalian cells or human lymphocytes cultured in vitro, peripheral blood lymphocyte micronucleus test 2. In vivo chromosome aberration test: in vivo chromosome aberration analysis of rat or mouse bone marrow cells, animal polychromatic erythrocyte micronucleus test

AMES experimental standard strains: TA98, TA97, 7A100, 7A102 (containing not only his mutations but also additional mutations)

Preparation of bacterial liquid and identification of bacterial strains

In vivo genetic mutation testing

Embryos in the organogenesis period are most sensitive to teratogens. When a teratogen comes into contact with the embryo during the sensitive period, it can cause different malformations depending on whether the embryo is at different stages of development (a few days after conception).

Species differences and individual differences are more obvious in teratogenesis 1. They may not all have teratogenic effects in different animals, and the types of malformations they cause may not be the same. 2. Interspecific differences, that is, differences between different strains of the same species, are also very obvious in teratogenic effects.

The relationship between dose and effect is complex 1. The dose-effect relationship is complex and has different causes. 2. The dose-response curve of teratogenic effects is relatively steep, that is, the teratogenic zone is relatively narrow. 3. There are still different opinions on the maximum no-effect dose of teratogenic effects.

(1) Mutations cause abnormal embryonic development (2) Enzymes that play an important role in development are inhibited or destroyed, affecting the normal development of the embryo, resulting in embryonic malformations (3) Interfering with maternal homeostasis (4) Disorders in the cell division process

Experimental Methods Animal Selection

Chemical carcinogenesis refers to the process by which chemicals (including organic, inorganic, natural and synthetic chemicals) cause tumors. Chemical carcinogens refer to chemicals that can induce tumors.

Characteristics of chemical carcinogens Most are electrophiles, a class of compounds with electrophilic groups in their molecular structure Affected by factors such as species, strain, gender and environment. There is a dose-response relationship Biological effects are persistent and delayed In animal experiments, when the doses are equal, the effect of administering the test substance multiple times is greater than that administered once. Generally related to the interaction with the genetic material of the host cell or other cellular macromolecules

Mechanism of action of chemical carcinogens

The main manifestations are damage to the central nervous system, including headache, dizziness, blurred vision, nausea, vomiting, salivation, diarrhea, and general weakness in mild cases. In severe cases, paroxysmal and tonic convulsions may occur, and even death due to loss of consciousness.

DDT degrades into low-toxic DDE, DDD and non-toxic DDA in the environment (DDA is a carboxylic acid substance, soluble in water and excreted in urine)

A small amount of organophosphorus will not be toxic after being absorbed by the human body, but when too much is taken in, it will still have effects.

Acute poisoning manifests as salivation, tearing, muscle tremors, pupil constriction, deep paralysis, difficulty breathing, and severe convulsions and death.

Mild cases include headache, dizziness, nausea and vomiting, severe cases include listlessness, irritability, and coma.