Project description:Transcriptional profiling of P. putida KT2440 cells comparing untreated cells with 1 mM indole or 50 μg/ml ampicillin or 1 mM indole plus 50 μg/ml ampicillin treated cells
Project description:Transcriptional profiling of A. oleivorans DR1 treated Ampicillin 100 M-BM-5g/ml for 15min . To identify effect of ampicillin in A. oleivornas DR1, the cells were grown to exponential phase (OD600 ~0.4) and treated ampicillin 100 M-BM-5g/ml for 15 min.
Project description:Transcriptional profile of Pseudomonas putida DOT-T1E grown in the presence of ampicillin (300 ug/ml) compared with the same cells grown in absence of ampicillin
Project description:Transcriptional profile of Pseudomonas putida DOT-T1E-18 grown in the presence of ampicillin (100 ug/ml) compared with the same cells grown in absence of ampicillin.
Project description:Background: Penicillins inhibit cell wall synthesis; therefore, H. pylori must be dividing for these antibiotics to be effective. Identifying growth responses to varying medium pH may allow design of more effective treatment regimens. Aim: To determine the effect of acidity on bacterial growth and the bactericidal efficacy of ampicillin. Methods: H. pylori were incubated in dialysis chambers suspended in 1.5L of media at various pHs with 5mM urea, with or without ampicillin, for 4, 8 or 16 hours, thus mimicking unbuffered gastric juice. Changes in gene expression, viability and survival were determined. The bacterial load of H. pylori infected gerbils was determined with and without profound acid inhibition. Results: At pH 3.0, but not at pH 4.5 or 7.4, there was decreased expression of ~400 genes, including many cell envelope biosynthesis, cell division genes and penicillin-binding proteins. In the presence of ampicillin, viability and survival declined at pH 4.5 and 7.4 but not at pH 3.0. Profound acid inhibition of H. pylori infected gerbils increased the antral bacterial load >3 fold, showing that elevation of intragastric pH stimulated growth. Conclusions: Ampicillin is bactericidal at pH 4.5 and 7.4, but not at pH 3.0, due to decreased expression of cell envelope and division genes at pH 3.0. Therefore, at pH 3.0, the pH at the gastric surface, the bacteria are non-dividing and persist with ampicillin treatment. A more effective inhibitor of acid secretion that maintains gastric pH near neutrality for 24 hours/day should enhance the efficacy of triple therapy and of amoxicillin, even allowing dual therapy for H. pylori eradication.
