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In vitro effects of listerial hemolysin on rat brain mitochondria
Abstract:
Crude hemolysin derived from Listeria monocytogenes, strains 9-125 and 1122-3, reduced phosphate utilization of rat brain mitochondria in a succinate system. Oxidation rates were not altered by addition of hemolysin to a concentration of 42 hemolytic units/ml, with a mitochondrial protein concentration of 2.3 mg/ml. At a mitochondrial protein concentration of 1.8 mg/ml, 42 hemolytic units/ml of hemolysin increased the inhibition of phosphate utilization and also reduced the oxygen uptake. An age differential was apparent, with mitochondria from young rats demonstrating uncoupling at a lower concentration of hemolysin.
Insights
Listeria monocytogenes hemolysin impairs rat brain mitochondrial function, reducing phosphate utilization and oxygen uptake. Young rats showed greater sensitivity to hemolysin-induced mitochondrial uncoupling.
Area of Science:
- Neuroscience
- Biochemistry
- Microbiology
Background:
- Listeria monocytogenes is a bacterium known to produce toxins.
- Mitochondria are crucial for cellular energy production.
- Disruptions in mitochondrial function are linked to neurological disorders.
Purpose of the Study:
- To investigate the effect of Listeria monocytogenes crude hemolysin on rat brain mitochondrial function.
- To determine the impact of hemolysin on oxidative phosphorylation and phosphate utilization.
Main Methods:
- Preparation of crude hemolysin from Listeria monocytogenes strains.
- Isolation of rat brain mitochondria.
- Measurement of mitochondrial oxygen uptake and phosphate utilization in a succinate system.
Main Results:
- Hemolysin reduced phosphate utilization in rat brain mitochondria.
- At specific concentrations, hemolysin inhibited phosphate utilization and decreased oxygen uptake.
- Mitochondria from younger rats exhibited uncoupling at lower hemolysin concentrations.
Conclusions:
- Listeria monocytogenes hemolysin directly affects mitochondrial bioenergetics.
- The toxin's impact on mitochondria is concentration-dependent and influenced by animal age.
- These findings suggest a potential mechanism for neurotoxicity by Listeria monocytogenes.