Anatomical element localization by EDXS in Grevillea exul var. exul under nickel stress

International audienc

X-ray diffraction and microscopy investigations of structural inhomogeneities in NiMnSb crystallised from the melt

Our present work investigates the structural properties of bulk NiMnSb prepared by growth from the melt, using various thermal regimes. We studied the compositional behaviour of the polycrystalline material obtained from stoichiometric 1:1:1 and respectively off-stoichiometric melts. The latter samples were grown with Mn excess up to 10% and respectively Ni deficiency between 2 and 10%. The X-ray diffraction and the Scanning electron microscopy complement each other in the characterisation of the phases occurring in the samples. The synthesis of NiMnSb starting from an initially stoichiometric mixture associated with a thermal treatment presenting plateaus gives the best results. Also, it seems that the presence of an excess of Mn is not sufficient to prevent the occurrence of the NiSb stray phase

Pulsed laser deposition of (Co, Fe)-doped ZnSnSb and MnGeSb thin films on silicon

International audienceFilms of the material systems ZnSnSb and MnGeSb doped with Fe and Co respectively have been grown by pulsed laser deposition on silicon. Room temperature Hall effect measurements show that all Fe-doped PLD films are n-type whereas MnGeSb:Co ones are p-type. Carrier concentrations vary with film thickness, resulting in ∼1017–1018cm−3 for ZnSnSb:Fe and ∼1020–1021cm−3 for MnGeSb:Co films. Carrier mobilities are of the order 102 cm2/Vs in the MnGeSb:Co films and between 102 and 103 cm2/V s in ZnSnSb:Fe. Curie points above room temperature have been found for samples of both material systems

Outer membrane vesicles catabolize lignin-derived aromatic compounds in Pseudomonas putida KT2440

Lignin is an abundant and recalcitrant component of plant cell walls. While lignin degradation in nature is typically attributed to fungi, growing evidence suggests that bacteria also catabolize this complex biopolymer. However, the spatiotemporal mechanisms for lignin catabolism remain unclear. Improved understanding of this biological process would aid in our collective knowledge of both carbon cycling and microbial strategies to valorize lignin to value-added compounds. Here, we examine lignin modifications and the exoproteome of three aromatic–catabolic bacteria: Pseudomonas putida KT2440, Rhodoccocus jostii RHA1, and Amycolatopsis sp. ATCC 39116. P. putida cultivation in lignin-rich media is characterized by an abundant exoproteome that is dynamically and selectively packaged into outer membrane vesicles (OMVs). Interestingly, many enzymes known to exhibit activity toward lignin-derived aromatic compounds are enriched in OMVs from early to late stationary phase, corresponding to the shift from bioavailable carbon to oligomeric lignin as a carbon source. In vivo and in vitro experiments demonstrate that enzymes contained in the OMVs are active and catabolize aromatic compounds. Taken together, this work supports OMV-mediated catabolism of lignin-derived aromatic compounds as an extracellular strategy for nutrient acquisition by soil bacteria and suggests that OMVs could potentially be useful tools for synthetic biology and biotechnological applications