The existence of a variety of Pseudomonas aereginosa that produced a melaninlike pigment was first reported by Radais (Compt. rend. soc. biol. 49:808, 1897) and confirmed by Gessard (Ann. inst. Pasteur 15:817, 1901). A strain of nonmotile gram-negative bacillus (1184) was isolated in this laboratory from the urine of a man with chronic pyelonephritis. The organism l)roduced a melaninlike pigmen...

A comparative analysis of the temperature dependence of energy-transducing reactions in spinach (Spinacia oleracea) chloroplasts and their sensitivity for uncouplers and energy-transfer inhibitors at different temperatures is presented. Arrhenius plots reveal two groups of transitions, around 19 degrees C and around 12 degrees C. Activities that show transitions around 19 degrees C include line...

Preparations from a variety of photosynthetic organisms carry out a light-dependent phosphorylation of adenosine diphosphate. These systems appear to be similar in one respect: photophosphorylation is stimulated by substances that may behave as reducing agents, or as electron carriers. In the present study, the photophosphorylation system in extracts of Rhodospirillum rubrum is found to be acti...

AIM The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties like disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect...

Pseudomonas aeruginosa PA14 cells resistant to the novel antimicrobial gallium nitrate (Ga) were developed using transposon mutagenesis and by selecting spontaneous mutants. The mutants showing the highest growth in the presence of Ga were selected for further characterization. These mutants showed 4- to 12-fold higher Ga minimal inhibitory growth concentrations and a greater than 8-fold increa...

With the increased focus on healthy eating and consuming raw vegetables, this study assessed the extent of contamination of fresh vegetables by Pseudomonas aeruginosa in Jamaica and examined the antibiotic susceptibility profiles and the presence of various virulence associated determinants of P. aeruginosa. Analyses indicated that vegetables from retail markets and supermarkets were widely con...

The resistance and pathogenesis of bacteria could be related to their ability to sense and respond to population density, termed quorum sensing (QS). Inhibition of the QS system is considered as a novel strategy for the development of antipathogenic agents, especially for combating drug-resistant bacterial infections. In the present study, the anti-QS activity of Onion peel ethylacetate fractio...

In members of the family Enterobacteriaceae, ampC, which encodes a beta-lactamase, is regulated by an upstream, divergently transcribed gene, ampR. However, in Pseudomonas aeruginosa, the regulation of ampC is not understood. In this study, we compared the characteristics of a P. aeruginosa ampR mutant, PAOampR, with that of an isogenic ampR+ parent. The ampR mutation greatly altered AmpC produ...