ANIMAL VIRUSES 



485 



analyses have been made only of the influenza virus (Knight, 1947b). As with 

 the base ratios, some differences were also observed here between the A and B 

 types, specifically in the amino acids arginine, glutamic acid, lysine, trypto- 

 phan, and tyrosine. In further work it will be necessary to differentiate 

 between the proteins of G antigen and virus-hemagglutinin. 



TABLE I 

 Peopobtion of Bases in the Nucleic Acid of Animal Viruses 



Influenza 



Infective particle 



A(PR8) 5 23.1 20.1 24.0 32.8 



A (MEL) 2 23.0 19.7 25.3 32.0 



A(WSE) 2 22.6 20.1 24.1 33.2 



A (Swine) 2 22.7 20.4 24.5 32.4 



A (CAM) 2 22.7 19.3 24.5 33.5 



Incomplete forms 

 A (PR8) a 



IDgo/HA = 4.5 1 23.6 20.0 24.1 32.3 



A (PR8) <» 

 ID50/HA = 3.9 1 23.0 20.3 24.4 32.3 



Infective particle 



B(LEE) 4 23.0 18.3 23.1 35.6 



B(MIL) 3 22.8 17.5 23.7 36.0 



E (ROB) 2 22.5 18.6 23.4 35.5 



Vaccinia 



Infective particle 



1 



29.5 



20.6 



20.0 



29.9 



" Undiluted passage virus from allantoic fluid. 



The lipid of the influenza and fowl plague infective particles is '--' 25 %* 

 and consists chiefly of phospholipid and cholesterol (Taylor, 1944; see Beard, 

 1948; Zillig et al., 1955). The amotmt of neutral fat seems to be negligible 

 according to recent investigations with influenza virus (Frommhagen et al., 

 1958). The treatment of the virus particles with ether results in their disin- 

 tegration and in a loss of infectivity (Hoyle, 1952; Schafer and Zillig, 1954). 

 Hence it would appear that the ether-soluble lipids are necessary for the 

 maintenance of the structure of the particles and are not impurities that are 

 difficult to remove. 



* Ada and Perry (1954b) claim that PR8-influenza virus contains 44% lipid. 



