20 research outputs found
Peptide and amino acid oxidation in the presence of thiosulfate by members of the genus Thermoanaerobacter
#Thermoanaerobacter brockii, #T. ethanolicus, #T. thermohydrosulfuricus, #T. finnii, and #Thermoanaerobacter strain SEBR 5268 (an isolate from an oil-producting well) were studied for their ability to oxidize proteinaceous compounds that included gelatin, peptides, and casamino acids. All bacteria tested used peptides and amino acids, but only slightly. However, in the presence of thiosulfate all the #Thermoanaerobacter species showed a substantial improvement in growth and/or the production of acetate, isovalerate, isobutyrate, and sulfide. Propionate was a minor product of peptide or amino acid oxidation. The reduction of thiosulfate during growth on peptides by members of the #Thermoanaerobacter$ species is a trait that closely resembles that of archaeal hyperthermophiles during growth on peptides and amino acids with elemental sulfur as electron acceptor. (Résumé d'auteur
Effect of thiosulphate as electron acceptor on glucose and xylose oxidation by Thermoanaerobacter finnii and Thermoanaerobacter sp. isolated from oil field water
#Thermoanaerobacter finnii fermente le glucose et le xylose en lactate, acétate, H2, CO2 et éthanol qui est le produit majeur du métabolisme. Une autre bactérie du genre #Thermoanaerobacter isolée d'une eau de gisement pétrolier produit des quantités aussi importantes d'éthanol que de lactate à partir de ces sucres. L'oxydation du glucose et du xylose par ces deux micro-organismes est complÚtement modifiée en présence de thiosulfate puisque, dans ces conditions, l'acétate devient le produit majeur du métabolisme des sucres. Cette modification du métabolisme amÚne à de meilleurs rendements cellulaires et à un meilleur taux de croissance bactérienne lorsque le thiosulfate est utilisé comme accepteur d'électrons. Une plus grande production d'acétate en présence de thiosulfate indique que les bactéries testées récupÚrent plus d'énergie des phosphorylations liées au substrat. Ces modifications observées sur le métabolisme des sucres en présence de thiosulfate nous amÚnent à tenir compte plus précisément du rÎle que peut jouer cet accepteur d'électrons dans l'oxydation de la matiÚre organique dans les sources chaudes riches en sulfate sulfuré ou les eaux de gisements pétroliers. (Résumé d'auteur
Evaluation of eight different bioinformatics tools to predict viral tropism in different human immunodeficiency virus type 1 subtypes
Human immunodeficiency virus type 1 (HIV-1) tropism can be assessed using phenotypic assays, but this is
quite laborious, expensive, and time-consuming and can be made only in sophisticated laboratories. More
accessible albeit reliable tools for testing of HIV-1 tropism are needed in view of the prompt introduction of
CCR5 antagonists in clinical practice. Bioinformatics tools based on V3 sequences might help to predict HIV-1
tropism; however, most of these methods have been designed by taking only genetic information derived from
HIV-1 subtype B into consideration. The aim of this study was to evaluate the performances of several
genotypic tools to predict HIV-1 tropism in non-B subtypes, as data on this issue are scarce. Plasma samples
were tested using a new phenotypic tropism assay (Phenoscript-tropism; Eurofins), and results were compared
with estimates of coreceptor usage using eight different genotypic predictor softwares (Support Vector Machine
[SVM], C4.5, C4.5 with positions 8 to 12 only, PART, Charge Rule, geno2pheno coreceptor, Position-Specific
Scoring Matrix X4R5 [PSSMX4R5], and PSSMsinsi). A total of 150 samples were tested, with 115 belonging
to patients infected with non-B subtypes and 35 drawn from subtype B-infected patients, which were taken
as controls. When non-B subtypes were tested, the concordances between the results obtained using the
phenotypic assay and distinct genotypic tools were as follows: 78.8% for SVM, 77.5% for C4.5, 82.5% for
C4.5 with positions 8 to 12 only, 82.5% for PART, 82.5% for Charge Rule, 82.5% for PSSMX4R5, 83.8% for
PSSMsinsi, and 71.3% for geno2pheno. When clade B viruses were tested, the best concordances were seen
for PSSMX4R5 (91.4%), PSSMsinsi (88.6%), and geno2pheno (88.6%). The sensitivity for detecting X4
variants was lower for non-B than for B viruses, especially in the case of PSSMsinsi (38.4% versus 100%,
respectively), SVMwetcat (46% versus 100%, respectively), and PART (30% versus 90%, respectively). In
summary, while inferences of HIV-1 coreceptor usage using genotypic tools seem to be reliable for clade
B viruses, their performances are poor for non-B subtypes, in which they particularly fail to detect X4
variants
Peptide and amino acid oxidation in the presence of thiosulfate by members of the genus Thermoanaerobacter
Thermoanaerobacter brockii, T. ethanolicus, T. thermohydrosulfuricus, T. finnii, and Thermoanaerobacter strain SEBR 5268 (an isolate from an oil-producing well) were studied for their ability to oxidize proteinaceous compounds that included gelatin, peptides, and casamino acids. All bacteria tested used peptides and amino acids, but only slightly. However, in the presence of thiosulfate all the Thermoanaerobacter species showed a substantial improvement in growth and/or the production of acetate, isovalerate, isobutyrate, and sulfide. Propionate was a minor product of peptide or amino acid oxidation. The reduction of thiosulfate during growth on peptides by members of the Thermoanaerobacter species is a trait that closely resembles that of archaeal hyperthermophiles during growth on peptides and amino acids with elemental sulfur as electron acceptor
Postâlesion upâregulation of 5âHT1B binding sites in the suprachiasmatic nucleus may be reversed after spontaneous or graftâinduced serotonin reinnervation
International audienceWe have previously reported that selective axotomy of serotoninergic neurons produced by an intraventricular injection of 5, 7âdihydroxytryptamine is followed by an increase in 5âHT1B binding sites in the suprachiasmatic nucleus of the hypothalamus. This postâlesion upâregulation is shown here to be spontaneously reversed after longâterm survival in spite of an incomplete reinnervation of the nucleus. Recovery may be accelerated by fetal raphe transplants that produce more rapid reinnervation
Effect of thiosulphate as electron acceptor on glucose and xylose oxidation by Thermoanaerobacter finnii and a Thermoanaerobacter sp. isolated from oil field water
During glucose and xylose fermentation, Thermoanaerobacter finnii was observed to produce lactate, acetate, H2 and CO2, with ethanol being the major end product. Thermoanaerobacter strain SEBR 5268, an isolate from an oil field, also produced a similar range of end product from glucose and xylose fermentation, with the exception that both ethanol and lactate were the major products of sugar metabolism. Both these strains were able to reduce thiosulphate to sulphide in the presence of these two substrates, with acetate being the dominant metabolite in that case. In addition, a faster growth rate and increased cell yield were obtained in the presence of thiosulphate, than in its absence. The higher concentrations of acetate produced in the presence of thiosulphate rather than without any electron acceptor indicated that more ATP was generated from substrate-level phosphorylation. These results have implications for our understanding of the breakdown of carbohydrates present in organic matter found in the natural ecological niches of Thermoanaerobacter species (sulphide-, elemental sulphur- or sulphate-rich thermal hot springs and oil fields)
Indirect evidence for an association of 5-HT1B binding sites with retinal and geniculate axon terminals in the rat suprachiasmatic nucleus
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Impairment of serotoninergic transmission is followed by adaptive changes in 5HT1B binding sites in the rat suprachiasmatic nucleus
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