Publications by authors named "Beth A McNichol"

Shiga toxin (Stx)-producing (STEC) strain B2F1 produces Stx type 2d, a toxin that becomes more toxic towards Vero cells in the presence of intestinal mucus. STEC that make Stx2d are more pathogenic to streptomycin (Str)-treated mice than most STEC that produce Stx2a or Stx2c. However, purified Stx2d is only 2- or 7-fold more toxic by the intraperitoneal route than Stx2a or Stx2c, respectively.

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To achieve widespread dissemination in the host, Bacillus anthracis cells regulate their attachment to host endothelium during infection. Previous studies identified BslA (Bacillus anthracis S-layer Protein A), a virulence factor of B. anthracis, as necessary and sufficient for adhesion of vegetative cells to human endothelial cells.

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Cytotoxic necrotizing factor type 1 (CNF1) and CNF2 are highly homologous toxins that are produced by certain pathogenic strains of Escherichia coli. These 1,014-amino-acid toxins catalyze the deamidation of a specific glutamine residue in RhoA, Rac1, and Cdc42 and consist of a putative N-terminal binding domain, a transmembrane region, and a C-terminal catalytic domain. To define the regions of CNF1 that are responsible for binding of the toxin to its cellular receptor, the laminin receptor precursor protein (LRP), a series of CNF1 truncated toxins were characterized and assessed for toxin binding.

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Article Synopsis
  • CNF1 and DNT are toxins with similar catalytic domains that modify specific glutamine residues in GTPases, leading to constitutive activation, but they induce different cellular effects on HEp-2 and Swiss 3T3 cells.
  • CNF1 causes multinucleation and is cytotoxic to Swiss 3T3 cells, whereas DNT does not affect HEp-2 cells morphologically but induces binucleation in Swiss 3T3 cells.
  • Research with chimeric and mutant toxins suggests that the enzymatic domain influences the phenotypic outcomes, and some mutations in the catalytic site can speed up transglutamination without completely inhibiting enzymatic activity.
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