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Abstract:
Specific aggregate formation of F pili was observed, by electron microscopy, in a mixture of male Escherichia coli (or of isolated F pili) and anti-f(+) serum. Cellular appendages other than F pili never showed such aggregation when mixed with anti-f(+) serum. The f(+) agglutinability of male cells, as well as F piliation, was sensitive to mechanical agitation. The f(+) agglutination was inhibited when appropriate numbers of phage M12, capable of attaching to F pili, were mixed with the male culture before the addition of anti-f(+) serum. Correlation between f(+) agglutinability and the extent of F piliation was observed. It was concluded that the F pilus is the structure of the f(+) antigen and is responsible for f(+) agglutination.
Insights
The F pilus, a structure on male Escherichia coli, is responsible for f(+) agglutination. Electron microscopy confirmed F pili aggregate with anti-f(+) serum, identifying them as the f(+) antigen.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Escherichia coli possess specialized appendages called F pili.
- These pili are involved in bacterial conjugation and express specific surface antigens.
Purpose of the Study:
- To identify the specific structure responsible for f(+) agglutination in Escherichia coli.
- To elucidate the role of F pili in the f(+) antigen-antibody reaction.
Main Methods:
- Electron microscopy was used to visualize aggregate formation.
- Agglutination assays were performed with male E. coli and anti-f(+) serum.
- Inhibition assays using bacteriophage M12 were conducted.
Main Results:
- Specific aggregation of F pili was observed with anti-f(+) serum.
- Other cellular appendages did not aggregate with the serum.
- F pilus aggregation and f(+) agglutinability were sensitive to mechanical agitation.
- Bacteriophage M12 inhibited f(+) agglutination, indicating its interaction with F pili.
- A correlation was found between f(+) agglutinability and the extent of F piliation.
Conclusions:
- The F pilus is the structural component of the f(+) antigen.
- F pili are directly responsible for the f(+) agglutination observed in male Escherichia coli.