The hemolysins of Staphylococcus aureus.

Wiseman, G M

doi:10.1128/mmbr.39.4.317-344.1975

Cited by 68 publications

(71 citation statements)

References 98 publications

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“…We are currently investigating the identity of this hemolysin in a ␤-hemolysin mutant background. Microaerobic conditions have previously been reported to increase expression of Hla in different S. aureus strains (52,67). Our studies showed no significant increase in hla transcription or activity under microaerobic compared to aerobic conditions (12).…”

Section: Discussioncontrasting

confidence: 47%

Role of SarA in Virulence Determinant Production and Environmental Signal Transduction in Staphylococcus aureus

Chan¹,

Foster²

1998

J. Bacteriol.

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The staphylococcal accessory regulator (encoded by sarA) is an important global regulator of virulence factor biosynthesis in Staphylococcus aureus. To further characterize its role in virulence determinant production, an sarA knockout mutant was created by insertion of a kanamycin antibiotic resistance cassette into the sarA gene. N-terminal sequencing of exoproteins down-regulated by sarA identified several putative proteases, including a V8 serine protease and a novel metalloprotease, as the major extracellular proteins repressed by sarA. In kinetic studies, the sarA mutation delays the onset of ␣-hemolysin (encoded by hla) expression and reduces levels of hla to approximately 40% of the parent strain level. Furthermore, SarA plays a role in signal transduction in response to microaerobic growth since levels of hla were much lower in a microaerobic environment than after aerobic growth in the sarA mutant. An exoprotein exhibiting hemolysin activity on sheep blood, and up-regulated by sarA independently of the accessory gene regulator (encoded by agr), was specifically induced microaerobically. Transcriptional gene fusion and Western analysis revealed that sarA up-regulates both toxic shock syndrome toxin 1 gene (tst) expression and staphylococcal enterotoxin B production, respectively. This study demonstrates the role of sarA as a signal transduction regulatory component in response to aeration stimuli and suggests that sarA functions as a major repressor of protease activity. The possible role of proteases as regulators of virulence determinant stability is discussed.

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Section: Discussioncontrasting

confidence: 47%

Role of SarA in Virulence Determinant Production and Environmental Signal Transduction in Staphylococcus aureus

Chan¹,

Foster²

1998

J. Bacteriol.

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“…The hemolytic activity iii the culture supernatant containing 10% rabbit serum was completely inactivated by heating for 10 min. However, the Arrhenius effect (22) was not observed. BSA-supplemented (0.05%) culture supernatant (D) were kept in a water bath at 56 C for appropriate time periods and cooled with running tap water immediately.…”

Section: Effect Of Heating On Hemolytic Activirymentioning

confidence: 83%

Hemolytic Activity of Leptospira interrogans Serovar canicola Cultured in Protein‐Free Medium

Yanagihara

Kojima²,

Mifuchi³

1982

Microbiology and Immunology

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Hemolytic activity of the culture supernatant of Leptospira interrogans serovar canicola strain Moulton grown in protein-free medium was demonstrated. The activity began to appear in the late logarithmic phase of growth of the organism and reached a plateau after 2 weeks of cultivation. It was inactivated by the addition of dipotassium ethylenediaminetetraacetate, but was effectively restored by Mg . Hemolysis by the culture supernatant was stimulated by "hot-cold" incubation. Sheep erythrocytes treated with the culture supernatant of the organism were transformed into spherocytes, in which invagination was observed. A hemolysin inhibitor in rabbit serum was found to be in the chloroform-methanol soluble fraction of the serum. The hemolysin of Leptospira may be phospholipase C.

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“…Hemolysins are one of the most important virulence factors of staphylococci. Staphylococcus aureus, which is a potentially pathogenic coagulase-positive species of this genus, produces four hemolysins -a, b, g and d. These toxins are well known and characterized, including the mechanism of their action (Wiseman, 1975;Bohach et al, 1997;Dinges et al, 2000;Foster, 2002). Coagulase-negative staphylococci (CoNS) rarely produce a or b hemolysin (Hebert, 1990;Molnar et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

The amino acid sequences and activities of synergistic hemolysins fromStaphylococcus cohnii

Mak¹,

Maszewska²,

Rózalska³

2008

FEMS Microbiology Letters

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Staphylococcus cohnii ssp. cohnii and S. cohnii ssp. urealyticus are a coagulase-negative staphylococci considered for a long time as unable to cause infections. This situation changed recently and pathogenic strains of these bacteria were isolated from hospital environments, patients and medical staff. Most of the isolated strains were resistant to many antibiotics. The present work describes isolation and characterization of several synergistic peptide hemolysins produced by these bacteria and acting as virulence factors responsible for hemolytic and cytotoxic activities. Amino acid sequences of respective hemolysins from S. cohnii ssp. cohnii (named as H1C, H2C and H3C) and S. cohnii ssp. urealyticus (H1U, H2U and H3U) were identical. Peptides H1 and H3 possessed significant amino acid homology to three synergistic hemolysins secreted by Staphylococcus lugdunensis and to putative antibacterial peptide produced by Staphylococcus saprophyticus ssp. saprophyticus. On the other hand, hemolysin H2 had a unique sequence. All isolated peptides lysed red cells from different mammalian species and exerted a cytotoxic effect on human fibroblasts.

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The hemolysins of Staphylococcus aureus.

Cited by 68 publications

References 98 publications

Role of SarA in Virulence Determinant Production and Environmental Signal Transduction in Staphylococcus aureus

Role of SarA in Virulence Determinant Production and Environmental Signal Transduction in Staphylococcus aureus

Hemolytic Activity of Leptospira interrogans Serovar canicola Cultured in Protein‐Free Medium

The amino acid sequences and activities of synergistic hemolysins fromStaphylococcus cohnii

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