Staphylococcus aureus NorA protein is a transmembrane multidrug efflux pump that confers low-level resistance to hydrophilic fluoroquinolones. The norA gene promoter is active in Escherichia coli HB101. We have examined the genetic basis of norA-mediated resistance in E. coli by introducing a wild-type norA gene into HB101 in plasmid pCL1921, pBR322, or pUC18 exhibiting copy numbers that spanne...

1 DCT Image Steganography Analysis for Privacy Preserving Data Mining; Sahar A. El-Rahman Ismail, Benha University, Cairo, Egypt and Princess Nora bint Abdul Rahman University, Riyadh, Saudi Arabia Dalal Al Makhdhub, Princess Nora bint Abdul Rahman University, Riyadh, Saudi Arabia Amal A. Al Qahtani, Princess Nora bint Abdul Rahman University, Riyadh, Saudi Arabia Ghadah A. Al Shabanat, Princes...

OBJECTIVES To delineate the role of capsaicin (8-methyl-N-vanillyl-6-nonenamide) as an inhibitor of the NorA efflux pump and its impact on invasion of macrophages by Staphylococcus aureus. METHODS Capsaicin in combination with ciprofloxacin was tested for activity against S. aureus SA-1199B (NorA overproducing), SA-1199 (wild-type) and SA-K1758 (norA knockout). The role of NorA in the intrace...

We characterized a Staphylococcus aureus norA gene expression regulator, NorR, initially identified from its binding to the norA promoter. The norR gene was 444 bp in length, located approximately 7 kb upstream from the norA gene, and encoded a predicted 17.6-kDa protein. Overexpression of norR in wild-type S. aureus strain ISP794 led to a fourfold decrease in sensitivity to quinolones and ethi...

Corresponding Author: Anurag Payasi Venus Medicine Research Centre, Hill Top Industrial Estate, Bhatoli Kalan, Baddi, H.P.-173205, India Email: [email protected] Abstract: Antimicrobial resistance caused by efflux systems is not widely studied in Staphylococcus aureus. In the present study, prevalence of NorA and NorB efflux pumps was studied in thirteen Methicillin-Resistant Staphylococcus au...

OBJECTIVES Multidrug efflux is a resistance mechanism that simultaneously affects susceptibility to many structurally unrelated compounds. The regulation of norA expression, which encodes the Staphylococcus aureus NorA multidrug efflux pump, is not well understood but the MgrA global regulator and the arlRS locus are involved. The expression of genes encoding proteins related to NorA, such as Q...

The prognostic significance of AgNOR proteins in stage II-III rectal cancers treated with chemoradiotherapy was evaluated. Silver staining was applied to the 3μm sections of parafin blocked tissues from 30 rectal cancer patients who received 5-FU based chemoradiotherapy from May 2003 to June 2006. The microscopic displays of the cells were transferred into the computer via a video camera. AgNOR...

Emerging drug resistance in clinical isolates of Staphylococcus aureus might be implicated to the overexpression of NorA efflux pump which is capable of extruding numerous structurally diverse compounds. However, NorA efflux pump is considered as a potential drug target for the development of efflux pump inhibitors. In the present study, NorA model was constructed based on the crystal structure...

staphylococcus aureus causes a wide variety of infections worldwide. methicillin-resistant s. aureus is one of most common causes of nosocomial and community acquired infections. the fluoroquinolones are an important class of antibiotics that used to treat infections caused by s. aureus. today, a significant increase in the rate of ciprofloxacin resistance in methicillin-resistant s. aureus str...

To dissect genetically the regulation of NorA, a multidrug transporter of Staphylococcus aureus, we analyzed the differential expression of the norA promoter using a transcriptional fusion with a beta-lactamase reporter gene. Expression studies with an arlS mutant revealed that the norA promoter is ArlS dependent. The arlR-arlS locus was shown to code for a two-component regulatory system. The ...