The capsule of Bacillus anthracis protects it from the bactericidal activity of human defensins and other cationic antimicrobial peptides.

During infection, Bacillus anthracis bacilli encounter potent antimicrobial peptides (AMPs) such as defensins. We examined the role that B. anthracis capsule plays in protecting bacilli from defensins and other cationic AMPs by comparing their effects on a fully virulent encapsulated wild type (WT) strain and an isogenic capsule-deficient capA mutant strain.

Using Telemetry Data to Refine Endpoints for New Zealand White Rabbits Challenged with .

We used a continuous-monitoring digital telemetry system to investigate temperature response in New Zealand White rabbits after inhalation or subcutaneous challenge with Bacillus anthracis. Two spore preparations of B. anthracis Ames A2084 were evaluated by using a nose-only inhalation model, and 2 strains, B.

Probing the donor and acceptor substrate specificity of the γ-glutamyl transpeptidase.

γ-Glutamyl transpeptidase (GGT) is a two-substrate enzyme that plays a central role in glutathione metabolism and is a potential target for drug design. GGT catalyzes the cleavage of γ-glutamyl donor substrates and the transfer of the γ-glutamyl moiety to an amine of an acceptor substrate or water. Although structures of bacterial GGT have revealed details of the protein-ligand interactions at the donor site, the acceptor substrate site is relatively undefined.

The cluster 1 type VI secretion system is a major virulence determinant in Burkholderia pseudomallei.

The Burkholderia pseudomallei K96243 genome encodes six type VI secretion systems (T6SSs), but little is known about the role of these systems in the biology of B. pseudomallei. In this study, we purified recombinant Hcp proteins from each T6SS and tested them as vaccine candidates in the BALB/c mouse model of melioidosis.

Capsule depolymerase overexpression reduces Bacillus anthracis virulence.

Capsule depolymerase (CapD) is a gamma-glutamyl transpeptidase and a product of the Bacillus anthracis capsule biosynthesis operon. In this study, we examined the effect of modulating capD expression on B. anthracis capsule phenotype, interaction with phagocytic cells and virulence in guinea pigs.

Treatment of experimental anthrax with recombinant capsule depolymerase.

Bacillus anthracis produces an antiphagocytic gamma-linked poly-D-glutamic acid capsule that is required for virulence. Capsule depolymerase (CapD) is a membrane-associated poly-gamma-glutamate-specific depolymerase encoded on the B. anthracis capsule plasmid, pX02, that is reported to contribute to virulence by anchoring the capsule to the peptidoglycan and partially degrading high-molecular-weight capsule from the bacterial surface.

Poly-gamma-glutamate capsule-degrading enzyme treatment enhances phagocytosis and killing of encapsulated Bacillus anthracis.

The poly-gamma-d-glutamic acid capsule confers antiphagocytic properties on Bacillus anthracis and is essential for virulence. In this study, we showed that CapD, a gamma-polyglutamic acid depolymerase encoded on the B. anthracis capsule plasmid, degraded purified capsule and removed the capsule from the surface of anthrax bacilli.

Anthrax capsule vaccine protects against experimental infection.

Efficacy of a poly-gamma-D-glutamic acid anthrax capsule vaccine was assessed in a mouse model of infection. Capsule by itself was protective against lethal challenge with a toxin(-), capsule(+) Bacillus anthracis strain. Conjugation of capsule to bovine serum albumin resulted in enhanced IgG anti-capsule antibodies measured by ELISA, but completely abrogated the protection.

The NheA component of the non-hemolytic enterotoxin of Bacillus cereus is produced by Bacillus anthracis but is not required for virulence.

A non-hemolytic enterotoxin (NHE) is one of the two enterotoxins thought to cause diarrhea produced by Bacillus cereus. We identified genes in Bacillus anthracis homologous to the B. cereus nheAB genes encoding proteins of the NHE complex.

Mode of action of pyrazinamide: disruption of Mycobacterium tuberculosis membrane transport and energetics by pyrazinoic acid.

Pyrazinamide is an important sterilizing drug that shortens tuberculosis (TB) therapy. However, the mechanism of action of pyrazinamide is poorly understood because of its unusual properties. Here we show that pyrazinoic acid, the active moiety of pyrazinamide, disrupted membrane energetics and inhibited membrane transport function in Mycobacterium tuberculosis.

The pncA gene from naturally pyrazinamide-resistant Mycobacterium avium encodes pyrazinamidase and confers pyrazinamide susceptibility to resistant M. tuberculosis complex organisms.

The antituberculosis drug pyrazinamide (PZA) needs to be converted into pyrazinoic acid (POA) by the bacterial pyrazinamidase (PZase) in order to show bactericidal activity against Mycobacterium tuberculosis. M. avium is naturally resistant to PZA.