PHOTOBIOLOGY OF RNA BACTERIOPHAGES .2. UV-IRRADIATION OF F2 - EFFECTS ON EXTRACELLULAR STAGEES OF INFECTION AND ON EARLY REPLICATION

Abstract— The effect of u.v. irradiation (2537 Å) on the RNA bacteriophage f2 has been studied with respect to the adsorption of f2 to E. coli K12 (male strain), the penetration of f2‐RN A into the host cell and the conversion of the phage nucleic acid to the double‐stranded replicative intermediate. The biological parameter most sensitive to u.v. was the plaque‐forming ability of the phage. Its loss could be attributed to several factors. (1). A binding of capsid protein to phage nucleic acid interfering with host penetration by the f2‐RNA. (2). Desorption of some irradiated phage at 37° from their attachment sites on the host. (3). Molecular alterations in the RNA preventing formation of the replicative intermediate within the host. The relationship of these factors to the lack of photoreactivability of irradiated f2 is discussed. Copyright © 1968, Wiley Blackwell. All rights reserved