Cytodifferentiation and Macromolecular Synthesis

List of Contributors

Foreword

Cytodifferentiation and Macromolecular Synthesis

Genetic Control of Protein Structure

Characteristics of the Gene-Protein System Selected for Study

Comparison of Gene Alterations and Protein Alterations

The Relationship of Amino Acid Substitutions to the Genetic Code

Suppressor Mutations—Alterations of the Translation Mechanism

Genetic Repression, Allosteric Inhibition, and Cellular Differentiation

Introduction

Regulation of Enzymatic Activity: Allosteric Effects

Regulation of Protein Synthesis in Bacteria

Negative Regulation Controlled by Specific Genetic Determinants

Operators and Polygenic Operons

Messenger RNA and Regulation at the Genetic Level

The Repressor

Genetic Regulation and Differentiation

Model Circuits

Conclusion

Epigenetic Control of Specific Protein Synthesis in Differentiating Cells

Isozymes

Physicochemical Nature of LDH

Subunit Hypothesis

Chemical Composition

Immunochemical Properties

Function of Isozymes

Quantitative Studies of Protein Synthesis in Some Embryonic Tissues

Protein Synthesis in the Explanted Chick Embryo

Protein Synthesis in Differentiating Tissues during Late Development

Chromosomes and CytodifFerentiation

Structural Considerations

Loops, Puffs, and Genes

Heterogeneity of Nuclear RNA

RNA Synthesis in Lampbrush Chromosome Loops

Control of Chromosomal Synthesis

Discussion

Concluding Remarks

The Plastids: Their Morphological and Chemical Differentiation

Introduction

Structure of the Mature Chloroplast

Relation of Chloroplast Structure to Photosynthetic Function

Morphological Changes in the Development of the Proplastid to the Chloroplast

The Effect of Light on Plastid Development

Chlorophyll Biosynthesis in the Developing Plastid

Inheritable Factors That Control the Plastids

Cytoplasmic Inheritance of Euglena Plastids

Origin of Plastid Types

Summary

Organization and Disorganization of Extracellular Substances: The Collagen System

Organization of Collagen

Experimental Lathyrism

Collagen Degradation in Animal Tissues

On Mechanisms of Elongation

Axis Extension Related to Ordered Synthesis of Cell Wall

Significance of Transverse Wall Texture in Elongation in Nitella

Polarized Light Microscopy

Peculiar Optical Properties of Elongating Cell Walls

Evidence for a Cytoplasmic Framework

The Cytoplasmic Framework—Its Action in Orienting Synthesis

Influences on the Orientation of the Cytoplasmic Framework

Role of Strain in the Orientation of the Cytoplasmic Framework

Nature of the Rectifying Mechanism

A Provisional Model

Discussion

Summary

Tissue Interaction and Specific Metabolic Responses: Chondrogenic Induction and Differentiation

Experimental Modification of Degrees of Differentiation Manifested by Tissue Dissociation and Short-Term Re-aggregation

An Apparently Anomalous Instance of Chondrogenesis in Explants of Embryonic Mesonephros

A More Detailed Account of the Interactions Involved in the Induction of Vertebral Cartilage

Discussion

Author Index

Subject Index