conclusions high-level antibiotic resistance can occur as a result of multidrug efflux pumps combined with other mechanisms of resistance. however, the association between over-expression of these genes and highly resistant clinical isolates cannot be ignored. results our results confirmed 203 and 60 p. aeruginosa isolates from burn and non-burn specimens, respectively. the most antibiotic resi...

conclusions pmf-dependent efflux mechanism appears to play an important role in the mdr phenotype of a. baumannii clinical strains. background multidrug-resistant (mdr) strains of acinetobacter baumannii have been increasingly reported as a major cause of nosocomial infections, and have created major therapeutic problems worldwide. objectives the aim of the present study was to evaluate the rol...

Mycobacterium smegmatis is able to grow and survive at acidic pH, and exhibits intracellular pH homeostasis under these conditions. In this study, the authors have identified low proton permeability of the cytoplasmic membrane, and high cytoplasmic buffering capacity, as determinants of intrinsic acid resistance of M. smegmatis. To identify genes encoding proteins involved in protecting cells f...

OBJECTIVES Therapy of AIDS patients infected with Mycobacterium avium is problematic due to its intrinsic resistance to antibiotics. We have characterized the efflux pump activity of M. avium wild-type strain through an automated fluorometric method and correlated it with intrinsic resistance to antibiotics. METHODS M. avium ATCC 25291(T) and Mycobacterium smegmatis mc(2)155 were evaluated fo...

Light regulation of photosystem I (PSI) biogenesis was studied in a unicellular green alga, Chlamydomonas reinhardtii. When Chlamydomonas cells were transferred from darkness to the light, mRNAs for both nuclear- and chloroplast-encoded PSI subunits were induced in concert. This light induction was inhibited by photosynthetic electron transport (PET) inhibitors, 3-(3,4 dichlorophenyl)-1,1-dimet...

The generation of transmembrane ion gradients by Oxalobacter formigenes cells metabolizing oxalate was studied. The magnitudes of both the transmembrane electrical potential (delta psi) and the pH gradient (internal alkaline) decreased with increasing external pH; quantitatively, the delta psi was the most important component of the proton motive force. As the extracellular pH of metabolizing c...