A New Growth Factor for Hemolytic Streptococci

Abstract

The neutralized active eluate added to the basic medium without any other growth factor gives visible growth. Addition of riboflavin intensifies the growth, but the addition of the various other growth factors mentioned above had no such effect. The final eluate had a deep yellow color. The addition of 0.6 cc of this eluate corresponding to 0.3 cc of the original crude tomato extract to 10 cc of the medium yielded good growth. The purified active substance like that of the crude juice withstood boiling at pH 7.0 or 4.0, for at least 6 hours, but was destroyed in autoclave; at pH 4.0 at room temperature the substance retains its activity for a long time. At pH 9.0 it is much less resistant to boiling; at this reaction the potency is lost after 2 to 3 weeks at room temperature. Boiling half an hour in 0.5 N HC1 or 0.5 N NaOH destroys the active substance. Heating in 3% K MnO4 or in 3% H2O2 destroys the active substance; Br2 destroys it quickly at room temperature. The active principle is sensitive to nitrous acid and formaldehyde even at room temperature; 0.1% formaldehyde caused prompt in-activation. The reactions with nitrous acid and formaldehyde indicate that the active factor contains an NH radical. The presence of an amino group suggests a relationship to biotin. However, this substance differs from biotin for it is less resistant to heating and particularly to alkaline reactions. The same difference exists in relation to the butyl factor of Woolley and the B-Y factor of Oxford for anaerobes. It is not identical with glutamine and p-amino benzoic acid because these substances have no activating effect on the growth of Str. hemolyticus.