Chemical Pesticides Mode of Action and Toxicology

INTRODUCTION Motivation Pesticides and Opinion A Great Market Nomenclature, Definitions and Terminology Helpful Reading Biochemistry and Cell Biology General Toxicology Insect Biochemistry, Plant Physiology, Neurophysiology Pesticides Side Effects of Pesticides WHY IS A TOXICANT POISONOUS Seven Routes to Death How to Measure Toxicity Endpoints Dose and Effect Dose and Response LD50 and Related Parameters Acute and Chronic Toxicity Interactions Mechanisms of Interactions Examples PESTICIDES INTERFERING WITH PROCESSES IMPORTANT TO ALL ORGANISMS Pesticides that Disturb Energy Production Anabolic and Catabolic Processes Synthesis of Acetyl Coenzyme A and the Toxic Mechanism of Arsenic The Citric Acid Cycle and Its Inhibitors The Electron Transport Chain and Production of ATP Inhibition of ATP Production Herbicides that Inhibit Photosynthesis Weak Organic Acids Free Radical Generators D1 - Blockers Inhibitors of Carotene Synthesis Protoporphyrinogen Oxidase inhibitors General SH-Reagents and Free Radical Generators Mercury Other Multisite Fungicides Pesticides Interfering with Cell Division Fungicides Herbicides Pesticides Inhibiting Enzymes in Nucleic Acid Synthesis BACILLUS THURINGIENSIS AND ITS TOXINS The Mechanism of Action d-endotoxins Biotechnology Engineered Plants Biology Commercial Products SPECIFIC ENZYME INHIBITORS Inhibitors of Ergosterol Synthesis Conclusions Herbicides that Inhibit Synthesis of Amino Acids Inhibitors of Chitin Synthesis Insecticides Fungicides Inhibitors of Cholinesterase Acetylcholinesterase Organophosphates Carbamates Development of Organophosphorus and Carbamate Insecticides Other Enzymes Inhibited by Organophosphates and Carbamates The Butyrylcholinesterases The Neurotoxic Target Enzyme (NTE) Carboxylesterases INTERFERENCE WITH SIGNAL TRANSDUCTION IN THE NERVES Potency of Nerve Poisons Selectivity The Nerve and the Nerve Cell Pesticides that Act on the Axon Impulse Transmission along the Axon Pyrethroids DDT and its Analogues Pesticides Acting on Synaptic Transmission Inhibitory Synapses The Cholinergic Synapses Calcium Channels as Possible Targets for Insecticides Summary PESTICIDES THAT ACT AS SIGNAL MOLECULES Insect Hormones Insect Endocrinology Juvenile Hormone Ecdysone Behaviour-Modifying Pesticides Pheromones Structure - Activity Relationships Pheromones used as Pesticides and Lures Plant Hormones TRANSLOCATION AND DEGRADATION OF PESTICIDES The Compartment Model The Bioconcentration Factor The Half-life The Area under the Curve Example Degradation of Pesticides by Micro-organisms Degradation by Adaption Degradation by Co-metabolism Kinetics of Degradation Importance of Chemical Structure for Degradation Examples The Degraders Soil Adsorption Why are Chemicals Adsorbed? Examples Desorption Evaporation Example Biotransformation in Animals Oxidation Epoxide Hydrolase Glutathione Transferase Hydrolases Glucoronosyltransferase and Sulfotransferase Stereospecific Biotransformation Designing Pesticides that have Low Mammalian Toxicity RESISTANCE TO PESTICIDES Resistance is an Inevitable Result of Evolution Questions about Resistance Biochemical Mechanisms Increased Detoxication Insensitive Target Enzyme or Target Receptor Site Resistance in Fungi Atrazine Resistance and Plants made Resistant by Genetic Engineering Resistance to Glyphosate Resistance to older Biocides used as Pesticides Resistance to the Third and Fourth Generation Pesticides How to Delay Development of Resistance Refuge Strategy Mixing Pesticides with Different Modes of Action and Different Detoxication Patterns Switching Life-stage Target Increased Sensitivity in Resistant Pests Inhibition of Detoxication Enzymes Conclusions PESTICIDES AS ENVIRONMENTAL HAZARDS Pesticides are Poisons Pesticides are Xenobiotics Various Types of Bias Benchmark Values Required Toxicological Tests for Official Approval of a Pesticide Residue Analysis of Residues in Food and the Environment Sampling Sample preparation Analysis Pesticide Residues in Food Toxicity Classification of Pesticides Definition of ADI and NOEL and Tolerance Limits Comparing Health Hazard of Pesticides with Other Toxicants Present in the Market Basket Elixirs of Death Nomenclature and Structure of Dioxins Dioxins in Pesticides Toxicology The Target Analysis Angry Birdwatchers, Youth Criminals, and Impotent Rats Clear Lake Peregrine Falcons and Other Birds of Prey Conclusions