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MUTATION OF THE BACILLUS OF RABBIT SEPTICEMIA.

¹Laboratories of The Rockefeller Institute for Medical Research.

The Journal of Experimental Medicine

|October 30, 2009

Summary

Bacterial mutation from Type D to Type G occurs spontaneously in cultures of rabbit septicemia bacillus. This D to G mutation is influenced by culture conditions and bacterial filtrates, indicating a fundamental change in bacterial protoplasm.

Area of Science:

Microbiology
Bacterial Genetics

Background:

The study investigates spontaneous mutations in microbial cultures.
Focuses on the transformation of Type D microbes to Type G.

Purpose of the Study:

To characterize the conditions influencing the D to G mutation in rabbit septicemia bacillus.
To understand the fundamental nature of this bacterial mutation.

Main Methods:

Culturing pure strains of Microbe D under various conditions (temperature, media).
Assessing mutation rates by observing Type G colony formation.
Evaluating the effect of bacterial filtrates and different media compositions (broth, serum, peptone).

Main Results:

The D to G mutation occurs spontaneously in aged broth cultures.

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Mutation rates are significantly affected by culture media, particularly peptone concentration, and bacterial filtrates.

High peptone concentrations promote rapid mutation, reaching up to 90% Type G in 5-6 days.

Type G mutants do not revert to Type D in rabbit serum.

Conclusions:

The D to G mutation represents a fundamental change in bacterial protoplasm, evidenced by altered acid agglutination properties.
Peptone is a key factor in promoting this specific bacterial mutation.
Bacterial filtrates can inhibit the mutation process.