The lungs of cystic fibrosis (CF) patients are commonly colonized with Pseudomonas aeruginosa biofilms. Chronic endobronchial P. aeruginosa infections are impossible to eradicate with antibiotics, but intensive suppressive antibiotic therapy is essential to maintain the lung function of CF patients. The treatment often includes beta-lactam antibiotics. How these antibiotics influence gene expre...

Global gene expression patterns of Bacillus subtilis in response to subinhibitory concentrations of protein synthesis inhibitors (chloramphenicol, erythromycin, and gentamicin) were studied by DNA microarray analysis. B. subtilis cultures were treated with subinhibitory concentrations of protein synthesis inhibitors for 5, 15, 30, and 60 min, and transcriptional patterns were measured throughou...

The first pathogenic mechanism of Porphyromonas gingivalis, which is mainly responsible for adult periodontal diseases, is the attachment of fimbriae appendages to oral epithelial cells. The ability of a subinhibitory concentration of azithromycin to inhibit the expression of fimbriae in various strains of P. gingivalis isolated was investigated. A one-eighth subinhibitory concentration of azit...

The aim of this study was to evaluate the activity of the EO and its major components of Ocimum basilicum var. Maria Bonita, a genetically improved cultivar, against the fluconazole sensitive and resistant strains of Candida albicans and Cryptococcus neoformans. Geraniol presented better results than the EO, with a low MIC (76 μg/mL against C. neoformans and 152 μg/mL against both Candida strai...

OBJECTIVES To ascertain the effects of subinhibitory concentrations of several antifungal agents on a virulence factor: secreted proteinase (Sap) activity and expression of SAP genes in Candida albicans. METHODS Enzyme assays and growth measurements, GFP-SAP2 promoter constructs and fluorescence measurement, transcript profiling and RT-PCR. RESULTS For seven of eight C. albicans isolates te...

Though traditionally perceived as weapons, antibiotics are also hypothesized to act as microbial signals in natural habitats. However, while subinhibitory concentrations of antibiotics (SICA) are known to shift bacterial gene expression, specific hypotheses as to how SICA influence the ecology of natural populations are scarce. We explored whether antibiotic 'signals', or SICA, have the potenti...

Early studies of the Bacteroides mobilizable transposon NBU1 established that excision, the first step in NBU1 transfer, requires exposure of the cells to tetracycline. More recently, we found that excision is also associated with growth phase; even after exposure to tetracycline, excision is detectable only after the cells enter late exponential phase. The tetracycline effect is mediated by a ...