Inhibiting materials for gamma phage adsorption to the cell wall of Bacillus anthracis, strain Pasteur No. 2-H

Effects of chlorpyrifos on the metabolic profiling of Bacillus megaterium strain RRB

Many microorganisms have been reported to degrade organic pollutants in the environment and plants, however, the specific information about the effect of organic pollutants on the metabolism of microorganisms is poorly investigated. In the present study, the effect of the pesticide chlorpyrifos on the metabolic profiling of Bacillus megaterium strain RRB was investigated using metabolomics. Our data show that chlorpyrifos acting as an energy source was readily concentrated in the strain RRB from the culture medium. During early cultivation, the shift in energy sources from tryptic soy broth to chlorpyrifos may temporarily cause the strain RRB to enter the starvation stage, where some synthesis-related amino acids and intermediates in the pathways of TCA cycle and pyridoxine metabolism were decreased. The increase of nucleotides and lysine may help the strain RRB cope with the starvation stage. During later cultivation, many metabolites including organic acids, nucleosides and sugar phosphates were gradually accumulated, which indicates that chlorpyrifos could be utilized by the stain RRB to generate metabolites bacteria needed. In addition, arginine acting as a nitrogen-storage amino acid was gradually decreased with later cultivation, suggesting that chlorpyrifos could not provide enough nitrogen for bacteria.

Identification of the Bacillus anthracis (gamma) phage receptor

Bacillus anthracis, a gram-positive, spore-forming bacterium, is the etiological agent of anthrax. It belongs to the Bacillus cereus group, which also contains Bacillus cereus and Bacillus thuringiensis. Most B. anthracis strains are sensitive to phage gamma, but most B. cereus and B. thuringiensis strains are resistant to the lytic action of phage gamma. Here, we report the identification of a protein involved in the bacterial receptor for the gamma phage, which we term GamR (Gamma phage receptor). It is an LPXTG protein (BA3367, BAS3121) and is anchored by the sortase A. A B. anthracis sortase A mutant is not as sensitive as the parental strain nor as the sortase B and sortase C mutants, whereas the GamR mutant is resistant to the lytic action of the phage. Electron microscopy reveals the binding of the phage to the surface of the parental strain and its absence from the GamR mutant. Spontaneous B. anthracis mutants resistant to the phage harbor mutations in the gene encoding the GamR protein. A B. cereus strain that is sensitive to the phage possesses a protein similar (89% identity) to GamR. B. thuringiensis 97-27, a strain which, by sequence analysis, is predicted to harbor a GamR-like protein, is resistant to the phage but nevertheless displays phage binding.