38() BACTERIOLOGICAL CHEMISTRY 



wliicli the ])ase8 giianiiie, adenine and cytosine are 

 arranged in the above formulae is still unknown. It is 

 considered probable that the phosphate groups are 

 attached at positions 2 and 3 in the ribose molecule in 

 the ribonucleic acids. In the animal, or desoxy ribonucleic 

 acids, the phosphate linkages are probably between 

 positions 3 and 5 of the desoxyribose, and uracil is replaced 

 by thymine. 



The tubercle bacillus gives nucleic acids of the animal, 

 desoxyribose, type, yielding adenine, guanine, cytosine 

 and thymine on hydrolysis, whilst M. phlei, the timothy 

 grass bacillus, contains guanine, cytosine and uracil, but 

 no thymine, correlating it with the plant nucleic acids. 

 The nucleic acid of the diphtheria bacillus contains 

 adenine, guanine, C3^osine, uracil and thymine so that 

 it is either a mixture of plant and animal nucleic acids 

 or a new type. Other bacteria yield nucleic acids con- 

 taining bases of the purine type only ; that from B. 

 anthracis gives adenine and guanine and that from 

 Azotobacter chroococciiyn contains guanine, adenine and 



NH— CO 



I I 



CH C ^NH 



hypoxanthine, II II \ , which is derived 



^^ II II CH ' 



il II /- 



N C N 



from adenine by deamination. The cells of streptococci 

 contain about 80 per cent, of protein and nucleoprotein, 

 of which nucleic acid constitutes 18 to 24 per cent, in 

 Smooth organisms and 14 to 17 per cent, in Rough cells. 

 The nucleic acid is a mixture of 10 to 30 per cent, desoxy- 

 ribose nucleic acid from nuclear material, and the 

 remainder ribonucleic acid from the cytoplasm. As was 

 mentioned on p. 332 the crystalline tobacco mosaic 

 virus consists of nucleoprotein of the plant or yeast type. 

 The psittacosis and vaccinia viruses, on the other hand, 

 are of the animal, desoxyribose type. Rough Type II 



