COMPOSITION OF THE BACTERIAL CELL 63 



given organism, together with enzymes and at least minimal quantities 

 of all the products of its metabolism. 



Regarding the nature of the protein substance in bacteria, but little 

 is known, although 50-80 per cent, of the dried substance of the 

 bacterial cell consists of protein and protein derivatives. Conspicuous 

 among these protein derivatives are the nuclein constituents, nucleins, 

 nucleoproteins, and nucleic acids; they occur constantly in bacteria 

 and apparently the greater part of the protein of the bacterial cell 

 consists of these nuclear constituents. Nucleins and nucleoproteins 

 have been isolated from many bacteria: from B. subtilis by Van de 

 Velde; 1 from the plague bacillus by Lustig and Galeotti; 2 from the 

 typhoid bacillus by Paladino-Blandini; 3 from the tubercle bacillus 

 by Von Ruck 4 and Ruppel; 5 from the diphtheria bacillus by Aronson; 6 

 and Carapelle 7 has identified a glyco-nucleo-protein in B. prodigiosus. 



Numerous observations indicate that nuclein bases (xanthin bases) 

 are found in bacterial cells; thus, Lustig and Galeotti 8 identified 

 xanthin in plague bacilli. Nashimura 9 obtained xanthin bases in the 

 dried residue of a water bacillus in the following amounts: xanthin 0.07 

 per cent.; guanin, 0.14 per cent.; adenin, 0.08 per cent. No hypox- 

 anthin was found. 



The amino-acids of bacterial protein have not been thoroughly 

 studied. The variable nitrogen content even of the same organism 

 as it is grown in different media and under different conditions would 

 suggest that quantitative determinations of nitrogenous substances 

 would be somewhat unsatisfactory. Qualitatively, so far as available 

 data show, many amino-acids found in protein of higher animals and 

 plants have been isolated or identified in bacterial cells. These amino- 

 acids appear to differ in amount in different organisms, and several 

 have not been isolated at all up to the present time. Vaughan, Wheeler, 

 and Leach 10 conclude that the bacterial substance contains carbo- 

 hydrates, nuclein bodies and polymers of mono- and diamino-acids. 

 They are glyco-nucleo-proteins. Kruse 11 and Vaughan 12 have arrived at 



1 Ztschr. f. phys. Chem., viii. 



2 Deutsch. med. Wchnschr., 1897, 225. 



5 Baumgarten's Jahresberichte, 1901, 228, ref. 



4 Prophylactic Immunization against Tuberculosis, Report No. 1, Asheville", 1912, 3. 



6 Ztschr. f. phys. Chem., 1898, xxvi. 



6 Arch. f. Kinderheilkunde, vol. xxx. 



7 Centralbl. f. Bakteriol., 1907, xliv, 440. 



8 Loc. cit. 



9 Arch. f. Hyg., xviii, 325. 



10 Tr. Assn. Am. Phys., 1902, p. 243. 



11 Allgemeine Microbiologie, p. 65. 



12 Protein Split Products, p. 437. 



