Characterization of staphylococcal  -lysin

Abstract

y-Lysh was purifed from Stuphyfococcus aureus strains Smith 5R and PG23 (a toxic shock syndrome isolate) by a combination of heparin-agarose and hydroxylapatite chromatography. Both strains produced two haemolytic components, designated y1 and yz. Though each component was weakly haemolytic they acted synergistically to potentiate haemolysis on rabbit, sheep and human blood. Rabbit and sheep erythrocytes were more sensitive to lysis by y-lysin than human erythrocytes. The molecular mass of y1 was 32 kDa and its PI value was 9.4. y2 had a molecular mass of 36 kDa and a PI value of 9.3. While both trypsin and papain acted synergistically with y2 to induce increased haemolysis, no such synergism was seen with yl. Also, protease inhibitors acted to inhibit synergism between y1 and y2. These findings suggest that y1 could be a protease.

Contribution of SecDF to Staphylococcus aureusresistance and expression of virulence factors

“…Slightly lower transcription levels were seen for coa in the secDF mutant (Figure 8), which is in line with our findings for its coagulation properties. As Newman carries a prophage in the hlb gene [39] and the gamma toxin is inhibited by sulfonated polymers in agar [40], we only looked at the transcription of the genes encoding α and δ toxins. hla amounts in the mutant were reduced compared to the wild type (Figure 8).…”

Panton-Valentine leucocidin and gamma-hemolysin from Staphylococcus aureus ATCC 49775 are encoded by distinct genetic loci and have different biological activities

“…This toxin, having a cytolytic effect on only human and rabbit PMNs (8,9), has been described recently as a marker of virulence, since PVL-producing strains were strongly associated (5,6,22) with necrotizing primary cutaneous infections, especially furuncles, and vice versa. A second toxin, gamma-hemolysin, was later identified as a bicomponent toxin (2,10,21,33) having lytic activity on erythrocytes from a wide range of animal species. Its leukotoxic capacity (16) was not generally considered.…”

“…Staphylococcus aureus is one of the most frequently isolated pathogens in hospital routine. It produces numerous virulence factors, including the bicomponent toxins gamma-hemolysin (2,10,21,28,33) and Panton-Valentine leucocidin (PVL) (8,9,20,(37)(38)(39). These toxins consist of two separately secreted and nonassociated proteins (class S and class F components) acting synergistically on human and rabbit polymorphonuclear cells, monocytes, and macrophages.…”

“…Furthermore, three other S. aureus bicomponent toxins which are leukotoxic, hemolytic, and structurally related have been reported. These toxins are (i) gamma-hemolysin (2,10,21,33), which is encoded by the hlg locus of strain Smith 5R (4), (ii) bovine leucocidin (or leucocidin R) (29), which is encoded by the lukR locus (31) of strain P83, and (iii) a leucocidin produced by a methicillin-resistant S. aureus (MRSA) strain which is encoded by the luk locus (12,23,24). These three loci all consist of two consecutive transcription units in the same orientation, the first encoding a single open reading frame (ORF) and the second encoding two ORFs.…”

Bacteriophage endolysins: A novel anti-infective to control Gram-positive pathogens

“…aureus (Clyne et al, 1992; Manoharadas et al, 2009; O'Flaherty et al, 2005; Rashel et al, 2007; Sass and Bierbaum, 2007; Sonstein et al, 1971). However, in most cases these enzymes show low activity or are difficult to produce in large quantities.…”