INGREDIENTS OF CULTURE MEDIA 267 



BACTO-GAS AMINO ACIDS, TECHNICAL (B231) 



Bacto-Casamino Acids, Technical is acid hydrolyzed casein. The hydrolysis is 

 carried out as in the preparation of Bacto-Casamino Acids, but the sodium 

 chloride and iron content of this product have not been decreased to the same 

 extent. Bacto-Casamino Acids Technical is recommended for use in culture media 

 where amino acid mixtures are required for a nitrogen source and the sodium 

 chloride content need not be low. It is particularly valuable in studying the 

 growth requirements of bacteria. 



Bacto-Casamino Acids, Technical is prepared according to the method sug- 

 gested by Mueller^ for use in the preparation o^ diphtheria toxin in a medium 

 containing nitrogen substances of chemical composition similar to amino acids 

 in simplicity. Later it was shown that the sodium chloride of the hydrolysate 

 was the limiting factor in the production of diphtheria toxin and a method was 

 described by Mueller and Miller^ for the reduction of this material in the 

 hydrolysate, see Bacto-Casamino Acids discussed above. 



Casein hydrolysates prepared according to Mueller's method^ have been used 

 for many purposes. Tetanus toxin of high potency was produced by Mueller and 

 Miller^ in a simple medium using this hydrolysate. 



Favorite and Williams* used a casein hydrolysate prepared according to the 

 method of Mueller^ for the production of staphylococcus enterotoxin and alpha 

 hemolysin. Mueller and Hinton^ used Bacto-Casamino Acids, Technical in a 

 medium for primary isolation of the gonococcus and meningococcus. Bacto- 

 Casamino Acids, Technical was used in agar-free media for the isolation of 

 Neisseria and also in a tellurite medium for the isolation of C orynebacterium, 

 described by Levin.^ Wolf used Bacto-Casamino Acids or Bacto-Casamino Acids, 

 Technical in the preparation of a medium for the testing of disinfectants. Mueller 

 and Miller^ used Bacto-Casamino Acids, Technical in their Tellurite Serum Agar 

 for a selective medium for diphtheria. This casein hydrolysate has been used 

 with excellent results in media for the cultivation of Hemophilus pertussis 

 according to the method described by Homibrook^ and by Verwey, Thiele and 

 Sage.io 



The following is an approximate analysis of Bacto-Casamino Acids, Technical : 



Total Nitrogen 8 per cent 



Sodium Chloride 37 per cent 



Ash 39 per cent 



1 J. Immunol., 37:103:1939. a J. Bact., 46:233:1943. 



a J. Immunol., 40:21:1941. 7 J. Bact., 49:463:1945. 



3 Proc. Soc. Exp. Biol. Med., 43:389:1940- ^ J- Bact., 51:743:1946. 



* J. Bact., 41:305:1941. 8 Public Health Reports, 54:1847:1939. 



^ Proc. Soc. Exp. Biol. Med., 48:330:1941. 10 J. Bact., 54:71:1947. 



BACTO-VITAMIN FREE CASAMINO ACIDS 



As the name implies, Bacto- Vitamin Free Casamino Acids is acid hydrolyzed 

 casein, free from vitamins. It is recommended for use in microbiological assay 

 rnedia and in studies on the growth requirements of microorganisms. A descrip- 

 tion of these media with references is given on page 216 to 230. Sarett^ used 

 Bacto- Vitamin Free Casamino Acids as the acid hydrolyzed casein in his studies 

 on p-aminobenzoic acid and pteroylglutamic acid as growth factors for Lacto- 

 bacilli. 



Bacto-Vitamin Free Casamino Acids is readily soluble in distilled water, 



