Subcellular Biochemistry: Volume 6

1 Structures, Properties, and Possible Biological Functions of Polyadenylic Acid.- 1. Introduction.- 2. Isolation and Detection of Poly(A).- 2.1. Methodology.- 2.2. Determination of the Size of Poly(A) Segments.- 3. Messenger RNA and the 3?-Terminal Poly(A) Sequence.- 3.1. Occurrence of Poly(A) in Living Organisms.- 3.2. Poly(A) Sequences in Prokaryotes.- 3.3. Messenger RNA Lacking Poly(A).- 3.4. Complexes of Poly(A) with Amino Acids and Proteins.- 4. Possible Biological Functions of Poly(A).- 4.1. Covalent Linkage of Poly(A) RNA.- 4.2. Transport of mRNA from the Nucleus to the Cytoplasm.- 4.3. Poly(A) and the Stability of mRNA.- 4.4. Poly(A) Involvement in the Binding of mRNA to Membranes.- 4.5. 3?-Terminal Poly(A) Sequences of mRNA and Protein Synthesis.- 4.6. Summary.- 5. Structure of Poly(A).- 5.1. Poly(A) at Neutral pH.- 5.2. Acidic Forms of Poly(A).- 5.3. Effect of Substituents on Poly(A) Structure.- 5.4. Synthesis of Analogues of Poly(A).- 5.5. Influence of Metal Ions on the Structure of Poly(A).- 6. Interaction of Poly(A) with Monomers and Polymers.- 6.1. Complexes of Low-Molecular-Weight Organic Compounds and Poly(A).- 6.2. Complexes of Poly(A) and Complementary Monomers.- 6.3. Interaction of Poly(A) with Poly(U) and Other Complementary Polynucleotides.- 7. Conclusions.- 8. References.- 2 Computer Simulation of Density-Gradient Centrifugation.- 1. Introduction.- 2. Some Aspects of the Basic Theory of Gradient Centrifugation.- 3. The Indirect Approach to Simulation of Gradient Centrifugation.- 4. The Compartmental Approach to Simulation of Gradient Centrifugation.- 5. The Analytical Approach to Simulation of Gradient Centrifugation.- 6. General Discussion.- 7. References.- 3 Crown-Gall and Agrobacterium tumefaciens: Survey of a Plant-Cell-Transformation System of Interest to Medicine and Agriculture.- 1. Introduction.- 2. Overview of the Process of Plant-Cell Transformation by Agrobacterium tumefaciens.- 3. Conditions for Plant-Cell Transformation by Agrobacterium tumefaciens.- 3.1. Dicotyledonous Host Plants or Gymnosperms.- 3.2. A Temperature below 30°C.- 3.3. A Wound or Wound Stimulus.- 4. Properties and Products of Agrobacterium tumefaciens.- 4.1. Induction of Crown-Galls.- 4.2. General Properties and Classification.- 4.3. Differential Ability to Use Unusual Amino Acids as Sole Nitrogen Source.- 4.4. Production of Plant Growth Substances.- 4.5. Production of Polysaccharides.- 4.6. Production of Vitamins.- 4.7. Production of Antibiotics.- 5. Molecular Components, Genetic Systems, and Search for the Tumor-Inducing Principle (TIP) of Agrobacterium tumefaciens.- 5.1. DNA and DNA Plasmids.- 5.2. An RNA Polymerase and Its Components.- 5.3. RNA.- 5.4. Ribosomes and Their Components.- 5.5. Bacteriophages and Their Components.- 6. Attempts to Define the Crown-Gall Tumor Cell.- 6.1. Transplantability.- 6.2. Presence of Unusual Amino Acids.- 6.3. Autonomy.- 6.4. Accelerated Growth Rate.- 6.5. Limited Capacity for Differentiation.- 7. On the Genetic Basis of the Formation of the Crown-Gall Tumor Cell.- 7.1. Experiments on the Reversion and Suppression of the Tumorous State.- 7.2. Experiments Directed to the Detection of Bacterial and Bacteriophage Genes and Gene Products in Crown-Gall Tumor Cells.- 8. Medical and Agricultural Interest in Crown-Gall/ Agrobacterium Research.- 9. References.- 4 The Petite Mutation in Yeast.- 1. Discovery and Initial Characterization.- 1.1. Introduction.- 1.2. Discovery.- 1.3. Genetic and Biochemical Characterization.- 2. Cytology and Ultrastructure of Petite Mutants.- 3. Mitochondrial DNA in Petite Mutants.- 3.1. Grande Yeast Mitochondrial DNA.- 3.2. Petite Yeast Mitochondrial DNA.- 3.3. Mitochondrial DNA Synthesis.- 4. Mitochondrial RNA in Petite Mutants.- 4.1. Grande Yeast Mitochondrial RNA.- 4.2. Petite Yeast Mitochondrial RNA.- 5. Mitochondrial Proteins in Petite Mutants.- 5.1. Synthesis of Mitochondrial Proteins.- 5.2. Tricarboxylic Acid Cycle and Other Enzymes.- 5.3. Respiratory-Chain C