33. NUCLEIC ACIDS OF THE BACTERIAL VIRUSES 229 



TABLE IV 



Morphology of Various Bacteriophages 



References 

 ° R. C. Williams, Cold Spring Harbor Symposia Quant. Biol. 18, 185 (1953). 

 6 R. C. Williams, Advances in Virus Research 2, 183 (1954). 

 c E. Kellenberger, Thesis, University de Geneva (1954). 

 d L. W. Labaw and V. M. Mosley, J. Bacteriol. 67, 576 (1954). 

 • N. D. Zinder, J. Cellular Comp. Physiol. 45, Suppl. 2, 23 (1955). 

 ' C. E. Hall, E. C. Maclean, and I. Tessman, J. Mol. Biol. 1, 192 (1959). 



ferred to some structure insensitive to P 32 decay provides a plausible, if 

 controversial, explanation of this important observation. 



III. Nucleic Acids of Other T Bacteriophages 



1. Infection with Bacteriophage T5 



Of the other T phages, To appears to be most similar in many respects 

 to the T-even phages, while Tl, T3, and T7 appear to comprise a dis- 

 tinct group. 



T5 is similar in size and DNA content to the T-even phages (Tables 

 I and IV), but differs from the latter most notably in that its DNA con- 

 tains the more common pyrimidine, cytosine, instead of the unusual 

 5-hydroxymethylcytosine. Other differences include host range, antigenic 

 composition, 171 ' 171a and a requirement for calcium for injection. 172 



Despite the important difference in nucleotide composition, several fea- 

 tures of the biochemistry 173 and radiobiology 6 of To infection have led 

 to suggestions that T5 be grouped with the T-even phages as a distinc- 

 tive type of bacterial virus. As with the T-even phages, infection with 

 T5 brings about an extensive degradation of the host DNA. 173 ' m The 



171 Y. T. Lanni, ./. Bacteriol. 67, 640 (1954). 

 •«■ F. Lanni, Science 128, 839 (1958). 



172 S. E. Luria and D. L. Steiner, ./. Bacteiiol. 67, 635 (1954). 



173 L. V. Crawford, Virology 7, 359 (1959). 



174 E. Pfefferkorn and H. Amos, Virology 6, 299 (1958). 



