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Cell membrane permeability and mitochondrial dysfunction-inducing activities in cell-free supernatants from Serpulina
1Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln 68583-0905, USA.
Abstract:
Membrane permeability (MP) and mitochondrial dysfunction-inducing (MDI) activities were detected in cell-free supernatants (CFS) of Serpulina hyodysenteriae, using either hemoglobin release from porcine red blood cells (RBC) or cytoplasmic lactate dehydrogenase release from porcine peripheral blood lymphocytes (PBL), and reduction of the 3-(4,5-dimethylthiazoyl-2-y1)-2,5-diphenyltetrazolium bromide dye by porcine PBL. The MP and MDI activities of CFS correlated with each other for serotype 1 and 2 isolates taken at different population densities; however, the kinetics of toxin production varied between each serotype. The loss of enteropathogenicity of two field isolates with nonpathogenic phenotypes and pathogenic isolates passaged up to 45 times in vitro was not attributable to a loss of either membrane permeability or mitochondrial dysfunction-inducing activity of cell-free supernatants. Results from this study suggested the potential for two separate toxins being involved in the pathogenesis of swine dysentery, with the MDI activity correlating with age susceptibility to clinical disease.
Insights
Serpulina hyodysenteriae toxins cause membrane permeability and mitochondrial dysfunction. These activities correlate with swine dysentery pathogenesis and age susceptibility, suggesting two distinct toxins.
Area of Science:
- Veterinary Microbiology
- Pathogenesis Research
- Swine Disease
Background:
- Swine dysentery, caused by Serpulina hyodysenteriae, poses a significant threat to swine health.
- Understanding the virulence factors of S. hyodysenteriae is crucial for developing effective control strategies.
Purpose of the Study:
- To investigate the membrane permeability (MP) and mitochondrial dysfunction-inducing (MDI) activities in cell-free supernatants (CFS) of S. hyodysenteriae.
- To determine the correlation between MP and MDI activities and the pathogenesis of swine dysentery.
- To explore the relationship between these activities and age-related susceptibility to the disease.
Main Methods:
- Detection of MP and MDI activities in CFS using porcine red blood cells (RBC) and porcine peripheral blood lymphocytes (PBL).
- Assays included hemoglobin release, lactate dehydrogenase (LDH) release, and MTT dye reduction.
- Correlation analysis of MP and MDI activities with different serotypes and population densities of S. hyodysenteriae.
Main Results:
- MP and MDI activities were detected in CFS of S. hyodysenteriae.
- A positive correlation was observed between MP and MDI activities for serotypes 1 and 2, though toxin production kinetics varied.
- Loss of enteropathogenicity in vitro did not correlate with a loss of MP or MDI activity.
- MDI activity showed a correlation with age susceptibility to clinical swine dysentery.
Conclusions:
- The study suggests the involvement of potentially two separate toxins in the pathogenesis of swine dysentery.
- Mitochondrial dysfunction-inducing activity is linked to age-related susceptibility to clinical disease.
- Further research is warranted to isolate and characterize these putative toxins.