Abstract
The cells of Salmonella enteritidis were sonically disintegrated under low temperature, and subjected to a ultracentrifugical procedure. The sediment obtained between the centrifugation at 3, 400g for 30 minutes and at 92, 600g for 60 minutes, was termed particulate fraction, and its supernatant fluid was supernatant fraction. The particulate fraction was treated with sodium deoxycholate as a membrane distrupting agent. By this treatment, it was demonstrated that “unit membrane” structure became to be discernible with difficulty in ultrathin sectioned preparations of the particulte fraction, and, at the same time, its dehydrogenase activities for lactate and succinate were markedly reduced. Moreover, the protective antigenicity for mice of the treated particulate fraction was distinctly inferior to that of the untreated control. However, by the addition of Freund's incomplete adjuvant to the treated particulate fraction, the lowered protective antigenicity was restored in some extent. The protective antigenicity of the supernatant fraction, the principal component of which is thought to be ribosomes, was weak. The addition of the Freund's incomplete adjuvant to the supernatant fraction again could enhance distinctly the antigenicity.
From above results a discussion was made on the significance of the unit membrane structure and the ribosomes, which are included simultaneously in the particulate fraction, in its protective antigenicity.
