DNA Cloning and the Analysis of Plasmid Structure and Function.- A. Introduction.- B. Restriction Endonucleases.- C. DNA Cloning.- D. Analysis of Plasmid Structure and Function.- E. Concluding Remarks.- References.- Peptide Bond Formation in Non-ribosomal Systems.- A. Introduction.- B. Recent Developments in Non-ribosomal Peptide Formation.- C. Coding Capacity of Non-ribosomal Systems.- References.- Opiate Receptors and Their Endogenous Ligands (Endorphins).- Opiate Receptors.- A. Introduction.- B. Properties of Opiate Receptors as Inferred from in vivo Studies.- C. Receptor Binding of Opiate Drugs in Tissue Homogenates.- D. Location of Opiate Receptors.- E. Opiate Receptor Isolation.- F. Opiate Receptor-Mediated Effects on Peripheral Autonomic Neuroeffector Transmission.- G. Opiate Receptor-Mediated Effects on the Synthesis of Cyclic Nucleotides.- Endorphins.- A. History.- B. Structures of the Endorphins Contained in ?-LPH.- C. Other Endorphins.- D. Structure-Activity Relationships.- E. Distribution of the Endorphins.- F. Pharmacology and Physiology of the Endorphins.- References.- Influence of DNA Complexing Compounds on the Kinetoplast of Trypanosomatids.- A. Introduction.- B. Classification and Developmental Stages.- C. Structural Organization of the kDNA.- D. Replication of the kDNA.- E. Function of the kDNA.- F. Dyskinetoplasty in the Trypanosomatidae.- G. Chemotherapy of Trypanosomiasis and kDNA Binding Drugs.- H. Intercalating Compounds.- I. Non-Intercalating Compounds.- J. Conclusions.- References.- Mechanisms of Lymphocyte Transformation.- A. Introduction.- B. Cellular Interactions.- C. Interactions of Mitogens with Lymphocytes.- D. Cellular Commitment to Transformation.- E. Surface Changes and Transmembrane Events.- F. Energy Metabolism.- G. Cyclic Nucleotides and Lymphocyte Transformation.- H. Alterations in Genetic Expression.- I. Mitogen-Induced DNA Synthesis.- K. Termination of Proliferation.- L. Conclusions.- References.- Effects of Drugs on Chloroplasts.- A. Introduction.- B. Sensitivity of Chloroplasts to Exogenous Factors.- C. Some Modern Support of the Theory of Prokaryotic Origin of Chloroplasts.- D. Antibiotics Inducing Hereditary Bleaching of Euglena gracilis.- E. Attempt to Explain the Mechanism of Induction of Hereditary Loss of Chloroplasts.- F. General Conclusions.- References.