Carotenoids are essential to protection against photooxidative damage in photosynthetic and non-photosynthetic organisms. In a previous study, we reported the disruption of crtD and crtC carotenoid genes in the purple bacterium Rubrivivax gelatinosus, resulting in mutants that synthesized carotenoid intermediates. Here, carotenoid-less mutants have been constructed by disruption of the crtB gen...

The facultative anaerobe, Bacillus cereus, causes diarrheal diseases in humans. Its ability to deal with oxygen availability is recognized to be critical for pathogenesis. The B. cereus genome comprises a gene encoding a protein with high similarities to the redox regulator, Rex, which is a central regulator of anaerobic metabolism in Bacillus subtilis and other Gram-positive bacteria. Here, we...

THE work of Harden [1901] and of Grey [1919, 1, 2] and others has shown that the end products of the bacterial degradation of glucose and of mannitol are qualitatively the same, but differ considerably in the relative quantity of the substances formed. Thus, under similar conditions of fermentation, B. coli communis produces twice as much alcohol from mannitol as it does from glucose, but much ...

Several members of the obligately aerobic genus Streptomyces are able to reduce nitrate, catalyzed by Nar-type respiratory nitrate reductases. A unique feature of Streptomyces coelicolor A3(2) compared with other streptomycetes is that it synthesizes three nonredundant Nar enzymes. In this study, we show that Nar2 is the main Nar enzyme active in mycelium and could characterize the conditions g...

Hopanoids methylated at the C-3 position are a subset of bacterial triterpenoids that are readily preserved in modern and ancient sediments and in petroleum. The production of 3-methylhopanoids by extant aerobic methanotrophs and their common occurrence in modern and fossil methane seep communities, in conjunction with carbon isotope analysis, has led to their use as biomarker proxies for aerob...

The aim of the present study was to evaluate the effects of local tetracycline on the occurrence of alveolar osteitis in rats, and on the microbiota associated to this infection. Forty Wistar rats were randomly assigned to 4 groups (n=10): I - the rats had the maxillary right incisor extracted and the alveolar wound did not receive any treatment; II - adrenaline and Ringer-PRAS were introduced ...

Aluminium (Al), an environmental toxin, is known to disrupt cellular functions by perturbing iron (Fe) homeostasis. However, Fe is essential for such metabolic processes as the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, the two pivotal networks that mediate ATP production during aerobiosis. To counter the Fe conundrum induced by Al toxicity, Pseudomonas fluorescens utilizes i...

A bacteriocin-like inhibitory substance producing Lactococcus lactis subsp lactis strain, ST1, isolated from goat milk of Iranian origin and with broad spectrum of activity and desirable technical properties was used for evaluating some futures of bacteriocin inhibitory activity. Cell growth and bacteriocin production studies were carried out in MRS medium incubated statically under uncontrolle...

Enterococcus faecalis is equipped with two pathways of glycerol dissimilation. Glycerol can either first be phosphorylated by glycerol kinase and then oxidized by glycerol-3-phosphate oxidase (the glpK pathway) or first be oxidized by glycerol dehydrogenase and then phosphorylated by dihydroxyacetone kinase (the dhaK pathway). Both pathways lead to the formation of dihydroxyacetone phosphate, a...

Campylobacter jejuni accounts for one of the leading causes of foodborne bacterial enteritis in humans. Despite being considered an obligate microaerobic microorganism, C. jejuni is regularly exposed to oxidative stress. However, its adaptive strategies to survive the atmospheric oxygen level during transmission to humans remain unclear. Recently, the clinical C. jejuni strain Bf was singled ou...