On the presence of beta-imidazolethylamine in the intestinal wall : with a method of isolating a bacillus from the alimentary canal which converts histidine into this substance / by Edward Mellanby and F.W. Twort.

  • Edward Mellanby
Date:
[1912?]
Catalogue details

Licence: In copyright

Credit: On the presence of beta-imidazolethylamine in the intestinal wall : with a method of isolating a bacillus from the alimentary canal which converts histidine into this substance / by Edward Mellanby and F.W. Twort. Source: Wellcome Collection.

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    well on ordinary Ringer’s solution. Even in redistilled water to which histidine has been added the bacillus grows well for a time, and large quantities of /3-1. are produced. The growth is not so good in distilled water as in Ringer’s solution. The production of the base is certainly greater if the histidine solution be more dilute. For instance we got larger yields of the base when OT °/o or ’05 °/o solutions of the histidine were inoculated with the bacillus than when we used a 1 °/o solution of histidine in Ringer. Besides estimating the quantity of base present in a solution after bacterial action by its action on the isolated uterus, we prepared the dipicrate of the base by the ordinary method. The bacilli are filtered off through kieselguhr and the solution neutralised and evaporated to dryness. This residue is extracted with methyl alcohol which is in turn evaporated off. The base is then crystallised out from a watery solution as the dipicrate. For a good yield of /3-1. from histidine, it is well then (1) To use a OT °/0 solution of histidine in Ringer’s solution. The solution must not be acid before inoculation. (2) To inoculate with the special bacillus taken from a glycerine- agar medium of not more than 24 hours’ growth. The growth is washed off the surface of the medium with a little normal saline and inoculated into the histidine medium with a sterile pipette. By this means a small amount of nutriment from the agar is also inoculated into the medium. The growth from two agar tubes should be used for every litre of OT °/0 histidine solution. (3) To allow a week’s incubation. The effect of acidity on the decomposition of histidine. Further experiments showed that, although the bacillus will grow quite well in an acid medium yet, under these circumstances, no /3-imidazol- ethylamine is produced from histidine. This can be easily proved either by inoculating a slightly acid medium containing histidine or by adding glucose to the medium. In the latter case the acid produced by the action of the bacillus on the sugar also prevents the production of the base. When using a salt solution as a medium, this is especially important, as there is not in this case the same production of alkaline bodies as in the case of peptone broth. This question of acidity may have an important bearing, in view of the attention which is being paid, at the present time, to the question
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