Antihemorrhagic Compounds as Growth Factors for the Johne's Bacillus. ∗

Abstract

One of the first bacterial growth factors to be studied in any detail was a substance necessary for the growth of the Johne's bacillus (Mycobacterium paratuberculosis) 1 . Twort and Ingranll showed that certain other acid-fast bacteria including the tubercle bacillus contained a necessary growth factor for the original cultivation of the Johne's bacillus. Crude concentrates of the active substance were prepared from Mycobacterium phlei. We have long been interested in the growth of the Johne's bacillus, and for some time have attempted to isolate the active growth factor. In this paper concentration of the active factor will be described and it will be shown that it can be replaced by the antihemorrhagic vitamins.

The strain of the Johne's bacillus grows as a dull, brittle, granular filni on the surface of liquid media. It always grows better in the presence of phlei cells or an extract of them, and we have not been able to subculture it more than 2 or 3 times on a purely synthetic medium although it has been artificially cultivated about 20 years. In our experience most strains of the Johne's bacillus become continuously cultivable on a synthetic medium, although the phlei factor is needed for priniary cultivation; but all strains always grow faster and give a better yield when the factor is present.

The basal medium was composed of the following substances per liter of solution :glycerol 70 cc, asparagine 5 g, sodium citrate 0.5 g, K₂HPO₄, 1 g, MgSO₄.7 H₂O 1 g, iron citrate 0.063 g. Twenty cc portions of this basal medium were sterilized by autoclaving in 50 cc Erlenmeyer flasks. Substances to be tested for growth factor activity were incorporated in the basal medium at suitable dilutions.