We have searched for sulfate-reducing bacteria in the feces of 41 healthy individuals and 110 patients from a Hepato-Gastro-Enterology Unit using a specific liquid medium (Test-kit Labège, Compagnie Française de Géothermie, Orléans, France). The 110 patients were separated in 22 patients presenting with inflammatory bowel diseases and 88 patients hospitalized for other lower (n=30) or upper (n=58) digestive tract diseases. Sulfate-reducing bacteria were isolated from 10 healthy individuals (24%), 15 patients presenting with inflammatory bowel diseases (68%), and 33 patients with other symptoms (37%). A multiplex PCR was devised for the identification of Desulfovibrio piger (formerly Desulfomonas pigra), Desulfovibrio fairfieldensis and Desulfovibrio desulfuricans, and applied to the above isolates. The strains of sulfate-reducing bacteria consisted of D. piger (39 isolates), D. fairfieldensis (19 isolates) and D. desulfuricans (one isolate). The prevalence of D. piger was significantly higher in inflammatory bowel disease patients (55%) as compared to healthy individuals (12%) or patients with other symptoms (25%) (P<0.05).
Solar-driven
coupling of water oxidation with CO2 reduction
sustains life on our planet and is of high priority in contemporary
energy research. Here, we report a photoelectrochemical
tandem device that performs photocatalytic reduction of CO2 to formate. We employ a semi-artificial design, which wires
a W-dependent formate dehydrogenase (FDH) cathode to a photoanode
containing the photosynthetic water oxidation enzyme, Photosystem
II, via a synthetic dye with complementary light absorption. From
a biological perspective, the system achieves a metabolically inaccessible
pathway of light-driven CO2 fixation to formate. From a
synthetic point of view, it represents a proof-of-principle system
utilizing precious-metal-free catalysts for selective CO2-to-formate conversion using water as an electron donor. This hybrid
platform demonstrates the translatability and versatility of coupling
abiotic and biotic components to create challenging models for solar
fuel and chemical synthesis.
Eight isolates of Desulfovibrio spp. have been obtained over 5 years from abdominal or brain abscesses or blood. In seven patients these strains were part of a mixed flora. One strain was isolated in pure culture from the blood of a patient with peritonitis of appendicular origin. According to the 16S rRNA gene sequences, this strain was close to Desulfovibrio fairfieldensis. The present report describes the fourth isolate of this recently described species to be isolated in pure culture or as a predominant part of the flora and to be associated with infectious processes. Thus, D. fairfieldensis may possess a higher pathogenic potential than other Desulfovibrio species.
Sulphate-reducing bacteria are important players in the global sulphur and carbon cycles, with considerable economical and ecological impact. However, the process of sulphate respiration is still incompletely understood. Several mechanisms of energy conservation have been proposed, but it is unclear how the different strategies contribute to the overall process. In order to obtain a deeper insight into the energy metabolism of sulphate-reducers whole-genome microarrays were used to compare
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