Chapter VI 

 The Initiation of Bacteriophage Infection 



Alan Garen and Lloyd M. Kozloff 



Biology Department, Massachusetts Institute of Technology, Cambridge, 

 Massachusetts, and Biochemistry Department, University of Chicago, 



Chicago, Illinois 



(Section VII was written by L.M.K., and the preceding sections by A.G.). 



I. Introduction 204 



II. Morphology and Composition of Bacteriophages 204 



A. Size and Shape 204 



B. Chemical and Morphological Components 205 



1. Purification 205 



2. Chemical Composition 2G6 



3. Organization of Protein and DNA 206 



4. Structural Units 207 



C. Properties of the Components of Phage T2 208 



1. Attachment to Bacteria 208 



2. Killing of Bacteria 209 



3. Serology 209 



in. The Bacterial Surface 210 



IV. Injection 211 



V. The Attachment Reaction 212 



A. Reversibility 212 



B. Influence of Temperature 213 



C. Influence of the Medium 214 



D. Tryptophan Reqiiirement 214 



E. Attachment to Noncellular Surfaces 215 



F. Rate of Attachment 216 



VI. Genetic Control of Attachment Specificity 217 



A. Resistant Cell Mutants 217 



B. Host-Range Mutants of Phages 219 



C. Genetic Control of Tryptophan Requirement 222 



D. Phenotypic Mixing 222 



VII. On the Mechanism of Invasion 223 



A. Alterations of Phage Tail Structure during Invasion 223 



1. Morphological Changes 223 



2. Removal of Tail Fibers 224 



3. Role of Zinc 226 



4. Contraction of Proximal Tail Protein 226 



B. Action of Phage Enzyme on the Host Cell Wall 228 



C. Release of Phage DNA 230 



D. Simimary of the Steps of Invasion 231 



203 



