CONTENTS IX 



V. Summary and Conclusion 353 



References 355 



V. Inactivation of Viruses by S. Gard and 0. Maal^e 359 



T. Introduction 360 



II. Physical Agents 361 



A. Mechanical Treatments 361 



B. Ionizing and Nonionizing Radiations 364 



III. Physicochemical Factors 382 



A. Heat Inactivation 382 



B. Resistance to Low Temperature and to Desiccation 387 



C. Virus Stability and pH 389 



D. Salt Effects 390 



IV. Chemical Agents 392 



A. Chemical Alterations of the Virus Particle not associated 

 with Loss of Infectivity 392 



B. Formaldehyde 398 



C. Protein-Denaturing Agents 405 



D. Oxidizing Agents 407 



E. Alkylating Agents 411 



F. Organic Solvents 412 



G. Enzymes 414 



H. Miscellaneous Agents 417 



References 418 



VI. The Chemical Basis of the Infectivity of Tobacco Mosaic Virus 



and Other Plant Viruses by H. Fraenkel-Conrat 429 



I. Purification of Plant Viruses 430 



A. Procedure for the Preparation of TMV 430 



B. Isolation and Properties of Other Plant Viruses 430 



C. The Nature of Virus-Specific Components in Infected 

 Plants 432 



II. Degradation of TMV 433 



A. Preparation of Nucleic Acid 433 



B. Preparation of Protein 435 



C. Structure and Function of Viral Proteins 435 



III. Assay of Infectivity of TMV and TMV-RNA 437 



IV. Reconstitution of TMV 439 



V. Infectivity of Viral RNA 441 



A. TMV 441 



B. Other Viruses 445 



C. Natural Occurrence of Infectious Nucleic Acid 446 



