Biomembranes

The volumes that have appeared in the three years since BIOMEMBRANES was launched illustrate the kinds of in­ formation the editor and the publishers envisaged would constitute the series. Some, such as this one, would consist of scholarly reviews of specialized topics; some, such as Volumes 2 and 3, would be the published chronicles of conferences; and others, such as Volumes 4 and 6, would be specialized monographs. In this way, we have hoped to provide not only reasoned critical opinions but also ideas "hot off the press. " Whether or not the views articulated ultimately stand the test of time is not as important as that their dissemination to the scientific community provides that unique stimulation that only flows from the interchange of ideas. This volumes includes chapters on a number of different topics. Rosenthal and Rosenstreich have reviewed the accumu­ lated evidence associating a visible structure of T lymphocytes, the Uropod, with immunologic "activation. " This is the first of many articles that will appear which associates the immune response with membrane function. A current example of Wallach's ability to approach a problem in a unique and original manner is contained in his review of the effects of ionizing radiation on membranes. Dale Oxender has been active in the study of transport for many years. His review is a careful documentary of the properties of specific binding proteins of bacteria and his thesis that these proteins are part of the active transport systems.

Contenu

1 The Lymphocyte Uropod: A Specialized Surface Site for Immunologic Recognition.- I. Introduction.- II. Classification of Lymphocytes.- III. Early Studies of Uropods on Mammalian Lymphocytes and Embryonic Cells.- IV. Uropods on Thymus-Derived or T Lymphocytes.- V. Morphologic Features of In Vivo and In Vitro Uropod-Bearing Lymphocytes.- VI. Absence of Uropods on Guinea Pig B Lymphocytes.- VII. Conclusion.- Acknowledgments.- References.- 2 Membrane Transport Proteins.- I. Introduction and Background.- II. Isolation of Components.- A. Membrane Preparations.- B. Osmotic-Shock Treatment.- C. Binding Assays.- III. Binding Proteins from Bacteria.- A. Inorganic Ions.- B. Amino Acids.- C. Carbohydrates.- IV. Chemotaxis and the Binding Proteins.- V. Role of the Binding Proteins in Transport.- A. Summary of Indirect Evidence.- B. Search for Direct Evidence.- VI. Summary.- References.- 3 The Membron: A Functional Hypothesis for the Translational Regulation of Genetic Expression.- I. Introduction.- II. Template Stability.- A. Microorganisms.- B. Embryonic Developments.- C. Cells of Adult Organisms.- III. Kinetics of Template Stabilization.- A. Experimental Approaches.- B. Prediction of Template Stability.- IV. Intracellular Membranes and Translational Regulation of Genetic Expression.- A. Interactions Between Polysomes and Membranes.- B. The Membrane-Conferred Stability of mRNA.- V. The Membron: Hypothetical Structure and Function.- A. General Parameters of the Regulatory Unit.- B. Theory of the Formation of Active Centers in the Membrane.- C. Conformation Change and the Membron.- D. Predictive Consequences of the Membron Hypothesis.- VI. Implications of the Membron Concept in the Regulation of Genetic Expression in Mammalian Systems.- Addendum.- Appendix I: Generation of Surfaces.- Appendix II: Conformational Membrane Changes.- References.- 4 Protein Synthesis by Membrane-Bound Polyribosomes.- I. Introduction.- II. Effects of Lipids and a Nonpolar Environment on Peptide Synthesis.- III. Effects of Lipophilic Agents on Protein Synthesis and Evidence for Initiation of Polyribosome Formation and Protein Synthesis on Membranes.- IV. A Review of the Evidence That Colicins Can Affect Protein Synthesis Without Entering the Cell.- V. Newer Evidence for the Presence of Amino Acids, Transfer RNA, Peptide Elongation Factors, Messenger RNA, and Ribosomes in Membranes.- VI. On the Possible Functions of Membrane-Bound Ribosomes.- A. Do Bound Ribosomes Make Only Secretory Proteins?.- B. Membrane-Bound Ribosomes Can Be Under the Control of the Membrane and Possibly Integrated with Other Membrane-Associated Activities.- C. Membrane-Bound Ribosomes May Take in Memory Consolidation Processes in Brain.- D. Membrane-Control of Biosynthesis in Contact Inhibition of Growth.- Addendum.- Acknowledgments.- References.- 5 Radiation Effects on Biomembranes.- I. Introduction.- A. The Genesis of Radiation Effects.- B. Measures of Radiation.- C. Direct and Indirect Effects.- D. "Weak Links".- II. Radiation Chemistry of Membrane-Associated Substances.- A. Water.- B. Proteins.- C. Lipids.- D. Sugar Radiolysis.- E. Effects of H2O2 and Radiosensitizers.- III. Effects of Ionizing Radiation on Membrane Morphology.- A. Erythrocytes.- B. Nervous Tissues.- C. Lymphoid Cells.- D. Lysosomes of Diverse Tissues.- IV. Radiation Effects on Membrane Function.- A. Transport.- B. Immune Response.- C. Axonal Conduction.- D. Lysosomes and Other Cytoplasmic Membranes.- V. Membrane SH-Groups.- VI. Nuclear Membrane.- VII. Pleiotropic Effects.- A. Survey of Data.- B. Interpretation in Terms of Cooperative Lattice Model.- Acknowledgments.- References.- 6 Protein Disposition in Biological Membranes.- I. Introduction.- II. The Lipid-Globular Protein Mosaic Model.- III. The Protein Crystal Model.- IV. Some Other Considerations.- V. Evidence for Proteins Which Penetrate and Span the Human Red Blood Cell.- VI. Conclusions.- Addendum.- Acknowledgments.- References.