scholarly journals Molecular Architecture of the Regulatory Locus sae of Staphylococcus aureus and Its Impact on Expression of Virulence Factors

2003 ◽  
Vol 185 (21) ◽  
pp. 6278-6286 ◽  
Author(s):  
Andrea Steinhuber ◽  
Christiane Goerke ◽  
Manfred G. Bayer ◽  
Gerd Döring ◽  
Christiane Wolz
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Capsular Polysaccharide ◽  
Virulence Gene ◽  
Open Reading Frames ◽  
Exponential Growth Phase ◽  
Molecular Architecture ◽  
Stem Loop ◽  
Transcriptional Initiation ◽  
Virulence Gene Expression

ABSTRACT We characterized the sae operon, a global regulator for virulence gene expression in Staphylococcus aureus. A Tn917 sae mutant was obtained by screening a Tn917 library of the agr mutant ISP479Mu for clones with altered hemolytic activity. Sequence analysis of the sae operon revealed two additional open reading frames (ORFs) (ORF3 and ORF4) upstream of the two-component regulatory genes saeR and saeS. Four overlapping sae-specific transcripts (T1 to T4) were detected by Northern blot analysis, and the transcriptional initiation points were mapped by primer extension analysis. The T1, T2, and T3 mRNAs are probably terminated at the same stem-loop sequence downstream of saeS. The T1 message (3.1 kb) initiates upstream of ORF4, T2 (2.4 kb) initiates upstream of ORF3, and T3 (2.0 kb) initiates in front of saeR. T4 (0.7 kb) represents a monocistronic mRNA encompassing ORF4 only. sae-specific transcripts were detectable in all of the 40 different clinical S. aureus isolates investigated. Transcript levels were at maximum during the post-exponential growth phase. The sae mutant showed a significantly reduced rate of invasion of human endothelial cells, consistent with diminished transcription and expression of fnbA. The expression of type 5 capsular polysaccharide is activated in the sae mutant of strain Newman, as shown by immunofluorescence and promoter-reporter fusion experiments. In summary, the sae operon constitutes a four-component regulator system which acts on virulence gene expression in S. aureus.

scholarly journals Staphylococcus aureus CcpA Affects Virulence Determinant Production and Antibiotic Resistance

2006 ◽  
Vol 50 (4) ◽  
pp. 1183-1194 ◽  
Author(s):  
Kati Seidl ◽  
Martin Stucki ◽  
Martin Ruegg ◽  
Christiane Goerke ◽  
Christiane Wolz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Capsular Polysaccharide ◽  
Protein A ◽  
Virulence Gene ◽  
Exponential Growth Phase ◽  
Virulence Determinants ◽  
Resistance Level ◽  
Virulence Gene Expression ◽  
Oxacillin Resistance

ABSTRACT Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786) in Staphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the ΔccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding α-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediate-resistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a modulator of virulence gene expression as well.

scholarly journals Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168305 ◽  
Author(s):  
Mara Baldry ◽  
Anita Nielsen ◽  
Martin S. Bojer ◽  
Yu Zhao ◽  
Cathrine Friberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression

scholarly journals Nigribactin, a Novel Siderophore from Vibrio nigripulchritudo, Modulates Staphylococcus aureus Virulence Gene Expression

Marine Drugs ◽  
2012 ◽  
Vol 10 (12) ◽  
pp. 2584-2595 ◽  
Author(s):  
Anita Nielsen ◽  
Maria Mansson ◽  
Matthias Wietz ◽  
Anders Varming ◽  
Richard Phipps ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Virulence Gene ◽  
Virulence Gene Expression

scholarly journals Novel Inhibitors of Staphylococcus aureus Virulence Gene Expression and Biofilm Formation

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47255 ◽  
Author(s):  
Yibao Ma ◽  
Yuanxi Xu ◽  
Bryan D. Yestrepsky ◽  
Roderick J. Sorenson ◽  
Meng Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Virulence Gene ◽  
Virulence Gene Expression

scholarly journals 18β-Glycyrrhetinic Acid Inhibits Methicillin-Resistant Staphylococcus aureus Survival and Attenuates Virulence Gene Expression

2012 ◽  
Vol 57 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Danyelle R. Long ◽  
Julia Mead ◽  
Jay M. Hendricks ◽  
Michele E. Hardy ◽  
Jovanka M. Voyich
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Virulence Gene ◽  
Glycyrrhetinic Acid ◽  
Licorice Root ◽  
Methicillin Resistant ◽  
Content Type ◽  
Virulence Gene Expression

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) has become a major source of infection in hospitals and in the community. Increasing antibiotic resistance inS. aureusstrains has created a need for alternative therapies to treat disease. A component of the licorice rootGlycyrrhizaspp., 18β-glycyrrhetinic acid (GRA), has been shown to have antiviral, antitumor, and antibacterial activity. This investigation explores thein vitroandin vivoeffects of GRA on MRSA pulsed-field gel electrophoresis (PFGE) type USA300. GRA exhibited bactericidal activity at concentrations exceeding 0.223 μM. Upon exposure ofS. aureusto sublytic concentrations of GRA, we observed a reduction in expression of key virulence genes, includingsaeRandhla. In murine models of skin and soft tissue infection, topical GRA treatment significantly reduced skin lesion size and decreased the expression ofsaeRandhlagenes. Our investigation demonstrates that at high concentrations GRA is bactericidal to MRSA and at sublethal doses it reduces virulence gene expression inS. aureusbothin vitroandin vivo.

scholarly journals Staphylococcus aureus CodY Negatively Regulates Virulence Gene Expression

2007 ◽  
Vol 190 (7) ◽  
pp. 2257-2265 ◽  
Author(s):  
Charlotte D. Majerczyk ◽  
Marat R. Sadykov ◽  
Thanh T. Luong ◽  
Chia Lee ◽  
Greg A. Somerville ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Regulatory Protein ◽  
Virulence Gene ◽  
Culture Fluid ◽  
Accessory Gene ◽  
Virulence Gene Expression ◽  
Gram Positive Bacteria ◽  
Accessory Gene Regulator ◽  
Branched Chain

ABSTRACT CodY is a global regulatory protein that was first discovered in Bacillus subtilis, where it couples gene expression to changes in the pools of critical metabolites through its activation by GTP and branched-chain amino acids. Homologs of CodY can be found encoded in the genomes of nearly all low-G+C gram-positive bacteria, including Staphylococcus aureus. The introduction of a codY-null mutation into two S. aureus clinical isolates, SA564 and UAMS-1, through allelic replacement, resulted in the overexpression of several virulence genes. The mutant strains had higher levels of hemolytic activity toward rabbit erythrocytes in their culture fluid, produced more polysaccharide intercellular adhesin (PIA), and formed more robust biofilms than did their isogenic parent strains. These phenotypes were associated with derepressed levels of RNA for the hemolytic alpha-toxin (hla), the accessory gene regulator (agr) (RNAII and RNAIII/hld), and the operon responsible for the production of PIA (icaADBC). These data suggest that CodY represses, either directly or indirectly, the synthesis of a number of virulence factors of S. aureus.

scholarly journals Fur is required for the activation of virulence gene expression through the induction of the sae regulatory system in Staphylococcus aureus

2011 ◽  
Vol 301 (1) ◽  
pp. 44-52 ◽  
Author(s):  
Miranda Johnson ◽  
Mrittika Sengupta ◽  
Joanne Purves ◽  
Emma Tarrant ◽  
Peter H. Williams ◽  
...  
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Regulatory System ◽  
Virulence Gene ◽  
Virulence Gene Expression
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