The Polymorphism of DNA --; I. Introduction --; II. A Summary of the Principles of DNA X-Ray Diffraction --; III. Generalities of DNA Transitions --; IV. B-like Structures --; V. The A Form --; VI. C-like Structures --; VII. Polynucleotide Polymorphism --; VIII. New Conformations of AT-rich DNA --; IX. Biological Relevance --; References --; Regulation of Bacteriophage T4 Gene Expression --; I. Introduction --; II. The Genetic Map of Coliphage T4 --; III. Resolution of the Early and Late Classes of T4- specific RNA --; IV. Resolution of the Quasi-late RNA --; V. Immediate-early and Delayed-early RNAs --; VI. Transcription of the Prereplicative Genes of Bacteriophage T4: The Read-through Mechanism --; VII. Delayed-early Promoters --; VIII. The Interrelationship between Translation and Elongation of Chains from Immediate-early Promoters --; IX. Requirements for True-late Transcription --; X. Transcription of the Quasi-late Genes --; XI. Turn-off of Early Gene Expression --; XII. T4-specific Modifications of DNA-dependent RNA Polymerase --; XIII. T4-specific Modification of the Host Translational Machinery --; XIV. Expression of the Endolysin Gene of Phage T4 --; References --; Defective Bacteriophages: The Phage Taillike Particles --; I. Introduction --; II. Structure --; III. Production --; IV. Bactericidal Activity --; V. Evolution --; VI. Conclusions --; References --; The Genesis of Multicellular Organization and the Control of Gene Expression in Diotyostelium discoideum --; I. Introduction --; II. The Migrating Slug --; III. Cell Association as an Initiator of Gene Expression --; IV. c-AMP, c-AMPsites, and the Morphogenetic Field of D. discoideum --; References --; Isoprenoids and Bacteriorhodopsin in Halobacteria --; I. Introduction --; II. General Features of Halobacteria --; III. Biosynthesis of Isoprenoid Compounds --; IV. The Purple Membrane and Bacteriorhodopsin --; V. The Photochemical Cycle in Bacteriorhodopsin --; VI. Function of Bacteriorhodopsin in the Halobacterial Cell --; VII. Biosynthesis of Bacteriorhodopsin and the Purple Membrane --; References --; Inhibitors of DNA Synthesis in RNA Tumor Viruses: Biological Implications and Their Mode of Action --; I. Introduction --; II. Requirements for DNA Synthesis by RNA Tumor Viruses --; III. Inhibition of Oncogenesis by RNA Tumor Viruses --; IV. Conclusion and Future Prospects --; References --; Adenosine as a Physiological Regulator of Coronary Blood Flow --; I. Introduction --; II. Control of Adenosine Production in Mammalian Heart --; III. Regulation of the Size of Cardiac Adenosine Pool --; IV. Adenosine Relaxation of Coronary Smooth Muscle --; V. Summary --; References.