A mutant, Vp-MX02, having a deletion in the gene (trh) for the thermostable direct hemolysin-related hemolysin (TRH) was constructed by double-crossover gene conversion from a TRH-producing Vibrio parahaemolyticus strain, TH3996. The deleted region was the upstream half of trh. Hemolysis was completely lost, and TRH antigen was undetectable in the mutant. Administration of the mutant into ligat...

Introduction .......................................................... 317 Production and Properties of the Hemolysins ........... ......................... 318 Alpha Hemolysin ......................................................... 318 Beta Hemolysin ......................................................... 325 Delta Hemolysin ......................................................... 329 Ga...

Group A streptococci strain C203S, grown in heart infusion broth with 0.3% maltose, produce two cellular hemolysins related to extracellular streptolysin S (SLS). Enzymatic lysis of the streptococci by group C streptococcal phage-associated lysin results in release of low titer, labile hemolysin, which can be stabilized by ribonucleic acid (RNA)-core (RNA preparation from yeast). This labile he...

The continuous flow paper electrophoretic methods used to isolate alpha hemolysin are presented. The purity of the alpha hemolysin preparation is demonstrated by double agar diffusion, immunoelectrophoretic, and ultracentrifugation techniques. Indirect evidence of purity is provided by the fact that rabbit immunized with purified alpha hemolysin produced detectable antibody only to alpha hemoly...

In an attempt to gain insight into the events that take place during Actinobacillus pleuropneumoniae infection, the present study was designed to ascertain the effects of bacterial toxicity on porcine neutrophil functions and viability. Incubation of phagocytes (2 x 10(6)) with opsonized A. pleuropneumoniae 4074 (2 x 10(7) CFU) resulted in phagocytic uptake of less than or equal to 4%. At the s...

The Escherichia coli hlyE gene (also known as clyA or sheA) codes for a novel pore-forming toxin. Previous work has shown that the global transcription factors FNR and CRP positively regulate hlyE expression by binding at the same site. Here in vivo transcription studies reveal that FNR occupies the hlyE promoter more frequently than CRP, providing a mechanism for the moderate upregulation of h...

Two hemolysin genes of Vibrio parahaemolyticus WP1, a thermostable direct (TSD) hemolysin gene and a thermolabile hemolysin gene, were cloned into the pBR322 vector in Escherichia coli K-12 C600. A large amount of the TSD hemolysin produced in E. coli K-12 accumulated in the periplasmic space. The TSD hemolysin gene was localized on a 0.9-kilobase HindIII-BamHI fragment by identifying qualitati...

An improved procedure for the isolation and purification of the hemolysin produced by a group B streptococcus was developed, and the inactivation of partially purified hemolysin by several enzymes was studied. Hemolysin obtained in buffer containing starch and Tween 80 was inactivated by subtilisin and alpha-amylase, suggesting that the hemolysin may consist of a protein hemolytic moiety comple...

Aeromonas hydrophila secretes several extracellular proteins including enterotoxin, hemolysin and aerolysin that are associated with the bacterial virulence. Previous studies have shown that two hemolytic toxins, hemolysin A and aerolysin A contribute to the virulence of Aeromonas hydrophila. In the current study, a total of 50 strains of Aeromonas hydrophila, including 28 (56%) strains isolate...

Haemophilus ducreyi, the etiologic agent of chancroid, a genital ulcer disease, produces a cell-associated hemolysin whose role in virulence is not well defined. Hemolysin is encoded by two genes, hhdA and hhdB, which, based on their homology to Serratia marcescens shlA and shlB genes, are believed to encode the hemolysin structural protein and a protein required for secretion and modification ...