Papillation in Bacillus anthracis colonies: a tool for finding new mutators

Area of Science:

• Microbiology
• Bacterial Genetics
• Molecular Biology

Background:

• Bacillus anthracis Sterne colonies exhibit papillation, indicating mutations enabling growth.
• Papillation arises from genetic alterations that overcome cellular growth limitations.

Purpose of the Study:

• To characterize the genetic basis of papillation in B. anthracis Sterne.
• To identify novel spontaneous mutators in B. anthracis using papillation as a screening tool.

Main Methods:

• Incubation of B. anthracis Sterne on Luria-Bertani medium at 30°C.
• Isolation and phenotypic analysis of papillae mutants (Group A and B).
• Genetic analysis of nprR gene mutations and identification of yycJ and recJ mutants.

Main Results:

• Group A papillae mutants possess mutations in the nprR gene.
• Disruption of yycJ or recJ genes confers a spontaneous mutator phenotype.
• yycJ mutator specificity resembles mismatch repair-deficient strains (MMR⁻).
• recJ deficiency specifically generates tandem duplications.

Conclusions:

• The nprR/papillation system serves as a novel mutational analysis tool for B. anthracis.
• yycJ and recJ are identified as key genes involved in spontaneous mutagenesis in B. anthracis.
• Characterization of mutational specificity provides insights into DNA repair mechanisms in B. anthracis.