1 Historical Introduction.- References.- 2 Fermentation and Mutational Development of the Tetracyclines.- A. Introduction.- B. The Producing Microorganisms.- I. Morphology and Ultrastructure.- II. Mutation and Strain Selection.- III. Cosynthesis.- C. The Fermentation Process.- I. Inoculum.- II. Contamination.- III. Complex Media.- IV. Synthetic Media.- V. Stimulators and Inhibitors.- VI. Directed Fermentations.- D. Fermentation Technology.- I. Aeration.- II. Temperature.- E. Concluding Remarks.- References.- 3 Structure Determination and Total Synthesis of the Tetracyclines.- A. Introduction.- B. Structure Determination.- I. Oxytetracycline.- II. Chlortetracycline.- III. Tetracycline.- IV. 6-Demethyltetracyclines.- V. 2-Acetyl-2-decarboxamidotetracyclines.- VI. 6-Methylenetetracyclines.- VII. 6-Deoxytetracyclines and 7- and 9-Substituted 6-Deoxytetracyclines.- VIII. Oxytetracycline Esters.- IX. Tetracycline Metal Chelates.- C. Partial Synthesis from Derivatives.- I. 4-Epitetracyclines.- II. 12a-Deoxytetracyclines.- III. 5a,6-Anhydrotetracyclines and 5a(11a)-Dehydrotetracyclines.- IV. 4-Oxotetracyclines-4,6-hemiketals and Tetracycloxides.- D. Total Synthesis of Tetracycline Derivatives and Incomplete Syntheses.- I. Aromatic A-Ring Compounds.- II. Analogues Lacking the Dimethylamino Group or Other Key Functionality.- E. Total Synthesis of 6-Demethyl-6-deoxytetracycline.- I. Woodward; Conover et al.- II. Muxfeldt et al.- F. Total Synthesis of Fermentation Tetracyclines.- I. Tetracycline: Shemyakin et al.- II. Chlortetracyclines: Muxfeldt et al.- III. Oxytetracycline: Muxfeldt et al.- G. Total Synthesis of Tetracycline Analogues.- I. dl-7-Chloro-6-deoxytetracyclines.- II. dl-8-Hydroxy-6-demethyl-6-deoxytetracycline.- III. dl-6-Thiatetracycline.- References.- 4 Biosynthesis of the Tetracyclines.- A. Introduction.- B. Production Strains.- I. Taxonomy.- II. Growth.- III. Genetics.- C. Building Units of Tetracyclines.- D. The Biosynthetic Pathway of Tetracyclines.- I. The Origin of the Tricyclic Nonaketide.- II. Transformations of the Tricyclic Nonaketide.- III. Transformation of the Tricyclic Decaketide.- IV. Genetic Loci Responsible for the Biosynthesis of Tetracyclines.- E. Regulation of the Biosynthesis of Tetracyclines.- E. Regulation of the Biosynthesis of Tetracyclines.- I. Saccharide Metabolism.- II. Formation of Malonyl CoA.- III. Energy Metabolism.- F. Biosynthesis of Macromolecules and the Production of Tetracyclines.- I. Nucleic Acid Metabolism.- II. Interaction of Tetracycline Antibiotics with Ribosomes.- III. Protein Synthesis.- IV. High-Phosphorylated Nucleotides.- G. Conclusion.- References.- 5 Chemical Modification of the Tetracyclines.- A. Introduction.- B. Semisynthetic Tetracyclines.- I. Modifications at the C1 and C3 Positions.- II. Modifications at the C2 Position.- III. Modifications at the C4 Position.- IV. Modifications at the C5 Position.- V. Modifications at the C5a Position.- VI. Modifications at the C6 Position.- VII. Modifications at the C7 and C9 Positions.- VIII. Modifications at the C11 and C12 Positions.- IX. Modifications at the C11a Position.- X. Modifications at the C12a Position.- XI. Structure-Activity Relationships.- C. Totally Synthetic Unnatural Tetracyclines.- I. General Synthetic Pathways.- II. Anhydrotetracyclines.- III. (±) B-Nortetracyclines.- IV. Modification at the C2 Position: (±)-4-Amino-7-chloro-2-N-methylcarbonyl-2-decarbonyl-4-dedimethylamino-6-demethyl-6-deoxytetracyclines.- V. Modifications at the C5a and C6 Positions: (±)-7-Chloro-6 deoxytetracyclines and (± )-7-Chloro-6-demethyl-6-deoxytetracyclines.- VI. Modification at the C7 Position: (±)-7-Methoxy-6-demethyl-6-deoxytetracyclines.- VII. Modification at the C8 Position: (±)-8-Hydroxy-6-demethoxy-6-deoxytetracyclines.- VIII. Modifications at the C5a Position: (±)-5a-Methyl-6-demethyl-6-deoxytetracyclines.- IX. Modifications at the C6 Position: 6-Heterotetracyclines.- D. Overall Structure-Activity Relationships.- I. Structural Requirements for Activity.- II. Structural Features Essential for Activity.- III. Effect of Structural Variation on Pharmacokinetics.- IV. Summary.- V. Conclusions.- References.- 6 Mode of Action of the Tetracyclines and the Nature of Bacterial Resistance to Them.- A. Introduction.- B. Mode of Action of the Tetracyclines: Studies Before 1964.- I. Introduction.- II. Early Studies (1948–1953) on the Mode of Action of Tetracyclines.- III. Studies (1953–1964) Identifying Protein Synthesis as the Primary Target for the Action of Tetracyclines.- C. Current Views on the Nature of Bacterial Protein Synthesis.- I. Introduction.- II. Structure of Ribosomes.- III. Initiation of Protein Synthesis.- IV. Recognition of Internal Codons.- V. Peptide Bond Formation and Translocation.- VI. Termination of Protein Synthesis.- D. Effects of Tetracyclines on Protein Synthesis in Prokaryotes.- I. Effects of Tetracyclines on the Synthesis of Protein In Vivo.- II. Effects of Tetracyclines on the Synthesis of Protein In Vitro.- E. Binding of Tetracyclines to Macromolecules.- I. Introduction.- II. Binding of Tetracyclines to Ribosomes.- F. Molecular Basis of Tetracycline Action.- G. Relation Between Structure and Activity in the Tetracyclines.- H. Effects of Growth in the Presence of Low Tetracycline Concentrations on Microbial Metabolism.- I. Selective Toxicity of the Tetracyclines.- I. Introduction.- II. Entry of Tetracyclines into Eukaryotic Cells.- III. Effect of Tetracyclines on Eukaryotic Protein Synthesis.- IV. Selective Toxicity of the Tetracyclines — The Apparent Paradox Explained.- J. Transport of Tetracyclines into Bacteria.- I. Introduction.- II. Transport of Tetracyclines Across the Gram-Negative Outer Membrane.- III. Transport of Tetracyclines Across the Cytoplasmic Membrane of Gram-Positive and-Negative Bacteria.- IV. Fluorescence Assay for Tetracycline Transport — A Cautionary Tale.- V. Transport of Tetracycline Across the Bacterial Cytoplasmic Membrane: Conclusion.- K. Plasmid-Determined Resistance to the Tetracyclines.- I. Occurrence of Plasmids in Natural Bacterial Isolates.- II. Tetracycline-Resistance Determinants: Transposable and Amplifiable Sequences.- III. Genetic Comparison of Regions Coding for Tetracycline Resistance.- IV. Proteins Synthesized by Tetracycline-Resistance Determinants: General Nature of the Proteins and Organization of the Genes Which Encode Them.- V. Mode of Action of Membrane-Located Resistance Proteins.- VI. Membrane Architecture in Relation to the Binding and Function of Plasmid-Determined Tetracycline-Resistance Proteins.- VII. Membrane-Located Resistance Proteins: Specific Properties and Comparisons Between Proteins Encoded by Different Determinants.- VIII. Gene Copy Number and Decreased Tetracycline Accumulation.- IX. Are the Membrane-Located Resistance Proteins That Mediate Efflux the Only Products Responsible for Resistance?.- X. Therapeutic Consequences of Tetracycline-Resistance Gene Amplification.- XI. Use of the Fluorescence Assay for Tetracycline for Studies on Plasmid-Determined Resistance.- XII. Inducibility of Plasmid-Determined Resistance to Tetracycline.- XIII. Expression of Tetracycline Resistance in Escherichia coli Renders Cells Hypersensitive to Lipophilic Chelating Agents.- XIV. Epidemiology of Tetracycline Resistance.- XV. Origin of Plasmid-Located Tetracycline-Resistance Genes.- L. Chromosomal Mutation to Tetracycline Resistance.- M. Conclusions.- References.- 7 Clinical Uses of the Tetracyclines.- A. Antimicrobial Activity.- B. Clinical Uses.- C. Treatment of First Choice.- D. Effective Alternative Treatment.- E. Treatment of Clinical Syndromes.- F. Ineffective Treatment.- G. Dosage and Duration of Therapy.- References.- 8 Nonmedical Uses of the Tetracyclines.- A. Historical.- B. Growth Promotion and Improved Feed Efficiency in Livestock.- I. Poultry.- II. Cattle.- III. Horses.- IV. Swine.- C. Disease Prevention Effects of Chlortetracycline and Oxytetracycline.- I. Poultry.- II. Ducks.- III. Chickens.- IV. Cattle.- V. Sheep.- VI. Swine.- D. Public Health Considerations.- I. Epidemiology of Antibiotic Resistance.- II. Salmonella.- III. Tissue Residues.- E. Government Restrictions.- I. Great Britain and Europe.- II. United States.- III. Far East.- References.