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Opsono-Adherence Assay to Evaluate Functional Antibodies in Vaccine Development Against Bacillus anthracis and Other Encapsulated Pathogens
Published on: May 19, 2020
THE STRUCTURE OF B. ANTHRACIS AND REVERSAL OF THE GRAM REACTION
1Laboratory of Experimental Therapeutics, Cornell University Medical College, New York.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Dyes like gentian violet alter Bacillus anthracis, reversing its Gram reaction and shrinking it. These changes, observed in other spore-forming bacteria, suggest a unique cell wall structure in B. anthracis.
Area of Science:
- Microbiology
- Bacteriology
Background:
- The Gram stain is a fundamental technique in bacterial identification.
- Bacillus anthracis, the causative agent of anthrax, possesses a complex cell structure.
Purpose of the Study:
- To investigate the effects of specific dyes on the Gram reaction and morphology of Bacillus anthracis.
- To explore the potential structural basis for observed dye-induced changes in B. anthracis and other bacteria.
Main Methods:
- Treatment of young B. anthracis cultures with aqueous solutions of gentian violet, acriflavine, or acriviolet.
- Observation of changes in Gram reaction, cell diameter, and weight.
- Detection of ninhydrin-positive substances in filtrates.
- Testing effects on various sporogenic aerobes and non-spore-bearing bacteria.
Main Results:
- Dyes reversed the Gram reaction and reduced cell diameter by approximately 40% in B. anthracis.
- Changes varied with bacterial strain and were accompanied by weight loss and release of ninhydrin-positive substances.
- Similar effects were observed in many sporogenic aerobes but not consistently in non-spore bearers.
- Modified Burke technique achieved partial decolorization of B. anthracis.
Conclusions:
- The observed phenomena suggest a Gram-positive cortex and Gram-negative medulla in B. anthracis.
- These structural hypotheses require further validation through techniques like bacterial cross-sections.
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