The N-Terminus of Apolipoprotein A-V Adopts a Helix-Bundle Molecular Architecture

Previous studies of recombinant full-length human apolipoprotein A-V (apoA-V) provided evidence of the presence of two independently folded structural domains. Computer-assisted sequence analysis and limited proteolysis studies identified an N-terminal fragment as a candidate for one of the domains. C-Terminal truncation variants in this size range, apoA-V(1-146) and apoA-V(1-169), were expressed in Escherichia coli and isolated. Unlike full-length apoA-V or apoA-V(1-169), apoA-V(1-146) was soluble in neutral-pH buffer in the absence of lipid. Sedimentation equilibrium analysis yielded a weight-average molecular weight of 18811, indicating apoA-V(1-146) exists as a monomer in solution. Guanidine HCl denaturation experiments at pH 3.0 yielded a one-step native to unfolded transition that corresponds directly with the more stable component of the two-stage denaturation profile exhibited by full-length apoA-V. On the other hand, denaturation experiments conducted at pH 7.0 revealed a less stable structure. In a manner similar to that of known helix bundle apolipoproteins, apoA-V(1-146) induced a relatively small enhancement in 8-anilino-1-naphthalenesulfonic acid fluorescence intensity. Quenching studies with single-Trp apoA-V(1-146) variants revealed that a unique site predicted to reside on the nonpolar face of an amphipathic R-helix was protected from quenching by KI. Taken together, the data suggest the 146 N-terminal residues of human apoA-V adopt a helix bundle molecular architecture in the absence of lipid and, thus, likely exist as an independently folded structural domain within the context of the intact protein

Comment ne pas perdre de vue les usage(r)s dans la construction d'une application à base d'ontologies ? Retour d'expérience sur le projet KmP

National audienceLe constructeur d'une application à base d'ontologies qui veut réaliser une application utile et utilisabledevrait se donner comme ligne directrice non pas simplement d'avoir en vue les usage(r)s de son application, mais surtout de ne pas les perdre de vueau cours du processus de construction. Comment ce constructeur peut-il faire pour ne pas perdre de vue les usage(r)s ? On fournit ici quelques éléments de réponse à cette question, qui reposent sur notre expérience du projet pluridisciplinaire RNRT KmP de serveur Web sémantique de compétences inter firmes

Des textes aux images : raconter autrement le fleuve Rhône

National audiencePeut-on cartographier un recueil de textes ? Les chercheurs ont extrait et dénombré les toponymes des nouvelles et des poèmes issus d'un concours littéraire consacré au Rhône et à la Saône, puis ont testé des modes de représentation, du graphe à la carte. L'étude des fréquences ou des cooccurrences éclaire les représentations des auteurs mais aussi les dispositifs de style qu'ils mettent en œuvre. Une telle mobilisation d’un corpus montre les liens qui peuvent unir littérature et géographie, ainsi que les moyens méthodologiques pour les faire communiquer

Des textes aux images : raconter autrement le fleuve Rhône

National audiencePeut-on cartographier un recueil de textes ? Les chercheurs ont extrait et dénombré les toponymes des nouvelles et des poèmes issus d'un concours littéraire consacré au Rhône et à la Saône, puis ont testé des modes de représentation, du graphe à la carte. L'étude des fréquences ou des cooccurrences éclaire les représentations des auteurs mais aussi les dispositifs de style qu'ils mettent en œuvre. Une telle mobilisation d’un corpus montre les liens qui peuvent unir littérature et géographie, ainsi que les moyens méthodologiques pour les faire communiquer

Symbiotic compatibility between rice cultivars and arbuscular mycorrhizal fungi genotypes affects rice growth and mycorrhiza-induced resistance

International audienceIntroduction: Arbuscular mycorrhizal fungi (AMF) belong to the Glomeromycota clade and can form root symbioses with 80% of Angiosperms, including crops species such as wheat, maize and rice. By increasing nutrient availability, uptake and soil anchoring of plants, AMF can improve plant’s growth and tolerance to abiotic stresses. AMF can also reduce symptoms and pathogen load on infected plants, both locally and systemically, through a phenomenon called mycorrhiza induced resistance (MIR). There is scarce information on rice mycorrhization, despite the high potential of this symbiosis in a context of sustainable water management in rice production systems.Methods: We studied the symbiotic compatibility (global mycorrhization & arbuscules intensity) and MIR phenotypes between six rice cultivars from two subspecies (indica: IR64 & Phka Rumduol; japonica: Nipponbare, Kitaake, Azucena & Zhonghua 11) and three AMF genotypes (Funneliformis mosseae FR140 (FM), Rhizophagus irregularis DAOM197198 (RIR) & R. intraradices FR121 (RIN)). The impact of mycorrhization on rice growth and defence response to Xanthomonas oryzae pv oryzae (Xoo) infection was recorded via both phenotypic indexes and rice marker gene expression studies.Results: All three AMF genotypes colonise the roots of all rice varieties, with clear differences in efficiency depending on the combination under study (from 27% to 84% for Phka Rumduol-RIN and Nipponbare-RIR combinations, respectively). Mycorrhization significantly (α=0.05) induced negative to beneficial effects on rice growth (impact on dry weight ranging from -21% to 227% on Azucena-FM and Kitaake-RIN combinations, respectively), and neutral to beneficial effects on the extent of Xoo symptoms on leaves (except for Azucena-RIN combination which showed a 68% increase of chlorosis). R. irregularis DAOM197198 was the most compatible AMF partner of rice, with high root colonisation intensity (84% of Nipponbare’s roots hyphal colonisation), beneficial effects on rice growth (dry weight +28% (IR64) to +178% (Kitaake)) and decrease of Xoo-induced symptoms (-6% (Nipponbare) to -27% (IR64)). Transcriptomic analyses by RT-qPCR on leaves of two rice cultivars contrasting in their association with AMF show two different patterns of response on several physiological marker genes

Surgical management of secondary hyperparathyroidism in chronic kidney disease—a consensus report of the European Society of Endocrine Surgeons

Despite advances in the medical management of secondary hyperparathyroidism due to chronic renal failure and dialysis (renal hyperparathyroidism), parathyroid surgery remains an important treatment option in the spectrum of the disease. Patients with severe and complicated renal hyperparathyroidism (HPT), refractory or intolerant to medical therapy and patients with specific requirements in prospect of or excluded from renal transplantation may require parathyroidectomy for renal hyperparathyroidism. METHODS: Present standard and actual controversial issues regarding surgical treatment of patients with hyperparathyroidism due to chronic renal failure were identified, and pertinent literature was searched and reviewed. Whenever applicable, evaluation of the level of evidence concerning diagnosis and management of renal hyperparathyroidism according to standard criteria and recommendation grading were employed. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled Hyperparathyroidism due to multiple gland disease: An evidence-based perspective