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Fluid accumulation in mouse ligated intestine inoculated with the vascular permeability factor produced by Bacillus
K Shinagawa1, K Sato, H Konuma
1Department of Veterinary Public Health, Faculty of Agriculture, Iwate University, Japan.
Abstract:
Partially purified vascular permeability (VP) factor (VPF) of Bacillus cereus induced fluid accumulation in the ligated intestinal loops of mouse (MIL) and rabbit (RIL), suggesting that the VP activity may correlate with fluid accumulation in ligated intestinal loops of these animals. Fluid accumulation was observed at 6-8 hr in 55-67% of mouse intestinal loops inoculated with 40-50 immunodiffusion units (IDU) of partially purified VPF, whereas it was found at 2 hr in all loops with 400-600 IDU of partially purified VPF. In rabbit intestinal loops with 120-190 IDU of partially purified VPF, fluid accumulation was observed at 6 hr. From these findings, VPF produced by B. cereus can be easily detected in both MIL and RIL. The intestinal tissue of mouse intestinal loops was histopathologically damaged at different concentrations of the VPF to induce fluid accumulation. With 50 IDU of partially purified VPF, severe edema was found in the laminia proprial layer and submucosa. With 600 IDU of partially purified VPF, on the other hand, severe necrosis in the surface epithelium of villus and laminia proprial layer, and hyperemia in the submucosa were observed, suggesting that partially purified VPF may be cytotoxic and/or intestinecrotic.
Insights
Bacillus cereus vascular permeability factor (VPF) causes fluid accumulation and tissue damage in mouse and rabbit intestinal loops. This study demonstrates VPF detection and its cytotoxic effects in vivo.
Area of Science:
- Microbiology
- Pathology
Background:
- Bacillus cereus produces toxins that can affect host tissues.
- Vascular permeability (VP) factor (VPF) is a known virulence factor.
Purpose of the Study:
- To investigate the effects of partially purified Bacillus cereus VPF on ligated intestinal loops in mice and rabbits.
- To assess the correlation between VPF activity and fluid accumulation.
- To evaluate the histopathological changes induced by VPF.
Main Methods:
- Partially purified VPF from Bacillus cereus was inoculated into ligated intestinal loops of mice and rabbits.
- Fluid accumulation was measured over time.
- Histopathological examination of intestinal tissues was performed.
Main Results:
- VPF induced significant fluid accumulation in both mouse intestinal loops (MIL) and rabbit intestinal loops (RIL).
- Fluid accumulation correlated with VPF concentration and time.
- Histopathology revealed dose-dependent tissue damage, including edema, necrosis, and hyperemia, indicating cytotoxic and intestinecrotic effects.
Conclusions:
- Partially purified Bacillus cereus VPF can be readily detected using MIL and RIL models.
- VPF exhibits cytotoxic and intestinecrotic properties, contributing to pathogenicity.