title: Variable expressions of Staphylococcus aureus bicomponent leucotoxins semiquantified by competitive reverse transcription-PCR.
abstract: A competitive reverse transcription-PCR method was developed for the semiquantitation of the expression of genes encoding bicomponent leucotoxins of Staphylococcus aureus, e.g., Panton-Valentine leucocidin (lukPV), gamma-hemolysin (hlgA and hlgCB), and LukE-LukD (lukED). The optimization procedure included RNA preparation; reverse transcription; the use of various amounts of enzymes, antisense primer, and RNA; and the final amplification chain reaction. Reproducible results were obtained, with sensitivity for detection of cDNA within the range of 1 mRNA/10(4) CFU to 10(2) mRNA/CFU, depending on the gene. Both specific mRNAs were more significantly expressed at the late-exponential phase of growth. Expression was about 100-fold higher in yeast extract-Casamino Acids-pyruvate medium than in heart infusion medium. Expression of the widely distributed gamma-hemolysin locus in the NTCC 8178 strain was around 10-fold diminished compared with that in the ATCC 49775 strain. Because of the lower level of hlgA expression, the corresponding protein, which is generally not abundant in culture supernatant, should be investigated for its contribution to the leucotoxin-associated virulence. The agr, sar, and agr sar mutant strains revealed a great dependence with regard to leucotoxin expression on the global regulatory system in S. aureus, except that expression of hlgA was not affected in the agr mutant.
authors.affiliation: UPRES EA-1318, LTAB-Institut de Bactériologie de la Faculté de Médecine, Université Louis Pasteur-Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: S
authors.initials: S
authors.lastname: Bronner
authors.forename: P
authors.initials: P
authors.lastname: Stoessel
authors.forename: A
authors.initials: A
authors.lastname: Gravet
authors.forename: H
authors.initials: H
authors.lastname: Monteil
authors.forename: G
authors.initials: G
authors.lastname: Prévost
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D005098:Exotoxins / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006460:Hemolysin Proteins; D007956:Leukocidins / Q000235:genetics / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003470:Culture Media; D005098:Exotoxins; D006460:Hemolysin Proteins; D007956:Leukocidins; C115218:LukD protein, Staphylococcus aureus; C115217:LukE protein, Staphylococcus aureus; D012329:RNA, Bacterial; D012333:RNA, Messenger; C086264:SAR protein, Lycopersicon esculentum; D015534:Trans-Activators; D014157:Transcription Factors; C037956:gamma-hemolysin, Staphylococcus aureus; C018579:leukotoxin; D020559:Monomeric GTP-Binding Proteins