Related Experiment Video
Updated: Jun 19, 2026

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43
Published on: September 11, 2020
A STABLE HEMOLYSIN-LEUCOCIDIN AND ITS CRYSTAL-LINE DERIVATIVE ISOLATED FROM BETA HEMOLYTIC STREPTOCOCCI
E J Czarnetzky1, I M Morgan, S Mudd
1Department of Bacteriology, School of Medicine, University of Pennsylvania, Philadelphia.
Abstract:
1. A chemically pure hemolysin-leucocidin has been isolated from beta hemolytic streptococci, but not from other species of bacteria studied. 2. It does not give rise to antibodies, but precipitates immune sera against hemolytic streptococci, and is therefore a hapten. 3. A highly purified sample of S. H. up to a dilution of 1:128,000 hemolyzes red blood cells. Its hemolytic activity is not specifically neutralized by antiserum versus beta hemolytic streptococci. It is leucocidic in that it inhibits the reduction of methylene blue by leucocytes. 4. The hemolysin-leucocidin is stable to oxygen, to heat and to moderate changes in hydrogen ion concentration. Its chemical structure has been determined in part. Its molecular weight is 2260. 5. A crystalline derivative has been isolated as the sodium salt from the hemolysin-leucocidin. As the free acid it has a molecular weight of 720. Its hemolytic and leucocidic activity parallels that of S. H., although it is not serologically active. It possesses a high degree of toxicity for mice and rabbits.
More Related Videos
06:05Using the Overlay Assay to Qualitatively Measure Bacterial Production of and Sensitivity to Pneumococcal Bacteriocins
Published on: September 30, 2014
08:14Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs
Published on: February 14, 2013