Cytotoxicity of Bacterial Metabolic Products, including Listeriolysin O, on Leukocyte Targets
Figure 1
Hemolytic activity of L. monocytogenes (a) and B. subtilis (b) strains. Spectrophotometric measurements of the hemolytic activity of the bacterial supernatants of Listeria monocytogenes (a) and Bacillus subtilis (b) strains tested on sheep erythrocytes (SRBC). The negative control was 20 L of BHI medium, 2% of final sample volume, exactly as in the tested supernatants. Hemolysis of the negative control was defined as zero hemolytic units (HU). The positive control absorbance was set to 100 HU, defined as the hemolysis caused by 20 μL of 0.5% SDS (0.01% final concentration). BR1-S (−) is B. subtilis strain grown without IPTG, BR1-S (+) the same strain induced with IPTG. Hemolytic activity of the bacterial strains was calculated according to the absorbance of controls. The average of three independent experiments () is indicated with bars showing standard deviation.
