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1.
Dalton Trans ; 51(30): 11340-11345, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35815476

ABSTRACT

For the first time, Na3SbS4·9H2O, also known as Schlippe's salt, has been synthesized through high-energy ball milling. This innovative synthesis way allows for obtaining high purity thioantimonate nonahydrate with around 90% yield in only approximately four hours. To validate the synthesis route described herein, the crystal structure has been refined, at room temperature, through high-resolution X-ray diffraction, pair distribution function analysis and energy dispersive spectrometry. Dehydration and rehydration of the compound have also been studied by thermogravimetric analysis and differential scanning calorimetry.

2.
Dalton Trans ; 50(28): 9725-9734, 2021 Jul 21.
Article in English | MEDLINE | ID: mdl-34165125

ABSTRACT

The new phase Na2VO(HPO4)2 was synthesized by sodium/proton ion exchange between NaI and VO(H2PO4)2 in hexanol. The exchange of two protons by two sodium ions causes a structural reorganization leading to a new original phase. The crystal structure was solved by continuous 3D Electron Diffraction, consisting of recording a video in diffraction mode during the continuous sample holder rotation in order to acquire a complete dataset in a shortest time in order to avoid the deterioration of this electron beam sensitive material. The individual Electron Diffraction patterns were extracted from the video, processed by conventional electron diffraction crystallography programs (PETS, JANA2006) and the resulting structural model calculated by the charge flipping algorithm was refined from powder X-ray diffraction data. This material crystallizes in an orthorhombic unit cell in the Iba2 (45) space group, with the cell parameters a = 13.86852(19), b = 13.7985(2), c = 7.47677(9). Electrochemical studies show that up to 0.66 Na f.u.-1 could be removed from Na2VO(HPO4)2.

3.
Crit Rev Microbiol ; 44(2): 182-211, 2018 Mar.
Article in English | MEDLINE | ID: mdl-28604247

ABSTRACT

The brucellae are facultative intracellular pathogens causing brucellosis, an important zoonosis. Here, we review the nutritional, genetic, proteomic and transcriptomic studies on Brucella carbon uptake and central metabolism, information that is needed for a better understanding of Brucella virulence. There is no uniform picture across species but the studies suggest primary and/or secondary transporters for unknown carbohydrates, lactate, glycerol phosphate, erythritol, xylose, ribose, glucose and glucose/galactose, and routes for their incorporation to central metabolism, including an erythritol pathway feeding the pentose phosphate cycle. Significantly, all brucellae lack phosphoenolpyruvate synthase and phosphofructokinase genes, which confirms previous evidence on glycolysis absence, but carry all Entner-Doudoroff (ED) pathway and Krebs cycle (and glyoxylate pathway) genes. However, glucose catabolism proceeds through the pentose phosphate cycle in the classical species, and the ED pathway operates in some rodent-associated brucellae, suggesting an ancestral character for this pathway in this group. Gluconeogenesis is functional but does not rely exclusively on classical fructose bisphosphatases. Evidence obtained using infection models is fragmentary but suggests the combined or sequential use of hexoses/pentoses, amino acids and gluconeogenic substrates. We also discuss the role of the phosphotransferase system, stringent reponse, quorum sensing, BvrR/S and sRNAs in metabolism control, an essential aspect of the life style of facultative intracellular parasites.


Subject(s)
Brucella/metabolism , Carbon/metabolism , Metabolic Networks and Pathways/genetics , Brucella/genetics , Gene Expression Regulation, Bacterial
4.
Dalton Trans ; 46(7): 2174-2183, 2017 Feb 14.
Article in English | MEDLINE | ID: mdl-28127602

ABSTRACT

Bornite Cu5FeS4-xSex (0 ≤ x ≤ 0.6) compounds have been synthesized, using mechanical alloying, combined with spark plasma sintering (SPS). High temperature in situ neutron powder diffraction data collected on pristine Cu5FeS4 from room temperature up to 673 K show that SPS enables the stabilization of the intermediate cubic (IC) semi-ordered form (Fm3[combining macron]m, aIC ∼ 10.98 Å) at the expense of the ordered orthorhombic form (Pbca, aO ∼ 10.95 Å, bO ∼ 21.86 Å, cO ∼ 10.95 Å) in the 300-475 K temperature range, whereas above 475 K the IC form coexists with the high temperature cubic (C) form (Fm3[combining macron]m, aC ∼ 5.50 Å). The ability of Se for S substitution to induce disorder and consequently to enhance the IC phase formation is also emphasized. This disordering effect is explained by the high quenching efficiency of the SPS method compared to conventional heating. The existence of topotactic phase transformations, as well as Se for S substitution is shown to have a significant effect on the transport properties. As expected, electrical transport properties indicate a change towards a more metallic behaviour with increasing Se content. The electrical resistivity reduces from ∼21.4 mΩ cm for the pristine Cu5FeS4 to ∼3.95 mΩ cm for Cu5FeS3.4Se0.6 at room temperature. A maximum power factor of 4.9 × 10-4 W m-1 K-2 is attained at 540 K for x = 0.4 composition. The influence of selenium substitution on the carrier effective mass and mobility is discussed based on single parabolic band approximation. Furthermore, a detailed investigation of the thermal conductivity by this isovalent anion substitution reveals a significant reduction of the lattice thermal conductivity due to the alloying effect. Finally, the important role of structural transitions in the thermoelectric properties is addressed. A maximum ZT of 0.5 is attained at 540 K for Cu5FeS3.8Se0.2 composition.

5.
FEBS Lett ; 585(19): 2929-34, 2011 Oct 03.
Article in English | MEDLINE | ID: mdl-21864534

ABSTRACT

"In vivo" bacterial nutrition, i.e. the nature of the metabolic network and substrate(s) used by bacteria within their host, is a fundamental aspect of pathogenic or symbiotic lifestyles. A typical example are the Brucella spp., facultative intracellular pathogens responsible for chronic infections of animals and humans. Their virulence relies on their ability to modulate immune response and the physiology of host cells, but the fine-tuning of their metabolism in the host during infection appears increasingly crucial. Here we review new insights on the links between Brucella virulence and metabolism, pointing out the need to investigate both aspects to decipher Brucella infectious strategies.


Subject(s)
Adaptation, Physiological/physiology , Brucella/metabolism , Brucella/pathogenicity , Animals , Brucella/genetics , Brucellosis/microbiology , Humans , Mutation , Quorum Sensing , Virulence
6.
Prev Vet Med ; 102(2): 118-31, 2011 Nov 01.
Article in English | MEDLINE | ID: mdl-21571380

ABSTRACT

Following the recent discovery of new Brucella strains from different animal species and from the environment, ten Brucella species are nowadays included in the genus Brucella. Although the intracellular trafficking of Brucella is well described, the strategies developed by Brucella to survive and multiply in phagocytic and non-phagocytic cells, particularly to access nutriments during its intracellular journey, are still largely unknown. Metabolism and virulence of Brucella are now considered to be two sides of the same coin. Mechanisms presiding to the colonization of the pregnant uterus in different animal species are not known. Vaccination is the cornerstone of control programs in livestock and although the S19, RB51 (both in cattle) and Rev 1 (in sheep and goats) vaccines have been successfully used worldwide, they have drawbacks and thus the ideal brucellosis vaccine is still very much awaited. There is no vaccine available for pigs and wildlife. Animal brucellosis control strategies differ in the developed and the developing world. Most emphasis is put on eradication and on risk analysis to avoid the re-introduction of Brucella in the developed world. Information related to the prevalence of brucellosis is still scarce in the developing world and control programs are rarely implemented. Since there is no vaccine available for humans, prevention of human brucellosis relies on its control in the animal reservoir. Brucella is also considered to be an agent to be used in bio- and agroterrorism attacks. At the animal/ecosystem/human interface it is critical to reduce opportunities for Brucella to jump host species as already seen in livestock, wildlife and humans. This task is a challenge for the future in terms of veterinary public health, as for wildlife and ecosystem managers and will need a "One Health" approach to be successful.


Subject(s)
Brucella/isolation & purification , Brucellosis/veterinary , Zoonoses/microbiology , Animals , Brucellosis/epidemiology , Brucellosis/microbiology , Female , Humans , Pregnancy , Zoonoses/epidemiology
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