Alanyl-Glutamine Restores Tight Junction Organization after Disruption by a Conventional Peritoneal Dialysis Fluid

Understanding and targeting the molecular basis of peritoneal solute and protein transport is essential to improve peritoneal dialysis (PD) efficacy and patient outcome. Supplementation of PD fluids (PDF) with alanyl-glutamine (AlaGln) increased small solute transport and reduced peritoneal protein loss in a recent clinical trial. Transepithelial resistance and 10 kDa and 70 kDa dextran transport were measured in primary human endothelial cells (HUVEC) exposed to conventional acidic, glucose degradation products (GDP) containing PDF (CPDF) and to low GDP containing PDF (LPDF) with and without AlaGln. Zonula occludens-1 (ZO-1) and claudin-5 were quantified by Western blot and immunofluorescence and in mice exposed to saline and CPDF for 7 weeks by digital imaging analyses. Spatial clustering of ZO-1 molecules was assessed by single molecule localization microscopy. AlaGln increased transepithelial resistance, and in CPDF exposed HUVEC decreased dextran transport rates and preserved claudin-5 and ZO-1 abundance. Endothelial clustering of membrane bound ZO-1 was higher in CPDF supplemented with AlaGln. In mice, arteriolar endothelial claudin-5 was reduced in CPDF, but restored with AlaGln, while mesothelial claudin-5 abundance was unchanged. AlaGln supplementation seals the peritoneal endothelial barrier, and when supplemented to conventional PD fluid increases claudin-5 and ZO-1 abundance and clustering of ZO-1 in the endothelial cell membrane.This work is part of the IMPROVE-PD project that has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement number 812699. M.B. is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Projektnummer 419826430. R.H. was supported by a research fellowship of the European Renal Association and European Dialysis and Transplant Association (ERA-EDTA). E.L. was supported by the ÚNKP-18-2 New National Excellence Program of the Ministry of Human Capacities, Hungary. E.L. and H.J. were supported by Jellinek-Harry scholarship. S.G.Z. acknowledges the Alexander von Humboldt Stiftung/Foundation for an Experienced Researcher Fellowship (2019–2021) and the International Peritoneal Dialysis Society (ISPD) for an International Cooperation Research Grant (2019–2021). C.P.S. has obtained funding from European Nephrology and Dialysis Institute (ENDI).Peer reviewe

Synthesis of 5-Hydroxyectoine from Ectoine: Crystal Structure of the Non-Heme Iron(II) and 2-Oxoglutarate-Dependent Dioxygenase EctD

As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine. A sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. This compound also functions as an effective osmostress protectant and compatible solute but it possesses properties that differ in several aspects from those of ectoine. The enzyme responsible for ectoine hydroxylation (EctD) is a member of the non-heme iron(II)-containing and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11). These enzymes couple the decarboxylation of 2-oxoglutarate with the formation of a high-energy ferryl-oxo intermediate to catalyze the oxidation of the bound organic substrate. We report here the crystal structure of the ectoine hydroxylase EctD from the moderate halophile Virgibacillus salexigens in complex with Fe3+ at a resolution of 1.85 Å. Like other non-heme iron(II) and 2-oxoglutarate dependent dioxygenases, the core of the EctD structure consists of a double-stranded β-helix forming the main portion of the active-site of the enzyme. The positioning of the iron ligand in the active-site of EctD is mediated by an evolutionarily conserved 2-His-1-carboxylate iron-binding motif. The side chains of the three residues forming this iron-binding site protrude into a deep cavity in the EctD structure that also harbours the 2-oxoglutarate co-substrate-binding site. Database searches revealed a widespread occurrence of EctD-type proteins in members of the Bacteria but only in a single representative of the Archaea, the marine crenarchaeon Nitrosopumilus maritimus. The EctD crystal structure reported here can serve as a template to guide further biochemical and structural studies of this biotechnologically interesting enzyme family

Visualisation interactive de données volumiques texturées pour la détection supervisée de failles en imagerie sismique

L'interprétation des images sismiques tridimensionnelles est une étape clé de l'exploration pétrolière. Les enjeux de cette activité sont de produire un modèle des différentes structures, telles que les failles, incluses au sein des données sismiques. Les objectifs multiples de cette thèse, menée en partenariat avec le groupe TOTAL, sont de concevoir, d'implémenter et de valider des techniques innovantes de visualisation et d'interaction aidant à la détection et à la modélisation des failles, supervisée par un interprétateur. Bien que spécifiquement développés à destination d'un contexte opéraionnel particulier, les outils proposés s'appliquent plus généralement à l'ensemble des données volumiques texturées ainsi qu'à la segmentation manuelle de structures tridimentionnelles. Ils s'inscrivent dans un cadre théorique et méthodologique nécessairement pluridisciplinaire qui concerne des domaines aussi divers que la spychologie expérimentale, l'imagerie cognitive, la réalité virtuelle ou encore l'interaction homme-machine.BORDEAUX1-BU Sciences-Talence (335222101) / SudocSudocFranceF

Short-term hemodynamic effects of immunoadsorption in dilated cardiomyopathy

BACKGROUND: Previous studies have shown that the sera of many patients with dilated cardiomyopathy (DCM) are positive for several antibodies directed against cardiac antigens. Anti-beta1-adrenergic receptor antibodies occur in 70% to 90% of DCM patients. These antibodies are extractable by immunoadsorption (IA). In an investigation of the functional significance of antibodies for hemodynamics, IA was performed throughout 5 consecutive days on nine patients with severe DCM who were on stable drug therapy. METHODS AND RESULTS: Immunoglobulins were eliminated in nine patients with severe DCM (mean age, 43.5 years; range, 25 to 58 years; left ventricular ejection fraction, <25%). IA was performed over 5 consecutive days with an immunoadsorber for immunoglobulin. All patients were on stable medication, including ACE inhibitors, digitalis, and diuretics. All patients received beta-blockers. During therapy, hemodynamic parameters (mean+/-SD) were monitored with a Swan-Ganz thermodilution catheter. IA elicited a decrease of anti-beta1-adrenergic receptor antibodies from 6.4+/-1.3 to 1.0+/-0.5 relative units. During IA, cardiac output increased from 3.7+/-0.8 to 5.5+/-1.8 L/min, P<.01. Mean arterial pressure decreased from 76.0+/-9.9 to 65.0+/-11.2 mm Hg, P<.05; mean pulmonary arterial pressure, from 27.6+/-7.7 to 22.0+/-6.5 mm Hg, P<.05; left ventricular filling pressure, from 16.8+/-7.4 to 12.8+/-4.7 mm Hg, P<.05; and systemic vascular resistance, from 1465+/-332 to 949+/-351 dyne x s x cm(-5), P<.01. CONCLUSIONS: In addition to conventional medical treatment, IA may be an additional therapeutic possibility for acute hemodynamic stabilization of patients with severe DCM

The solubility of rice straw silica and its use as a silicon source in paddy cultivation

SIGLEAvailable from British Library Document Supply Centre- DSC:DX182314 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Alanyl-glutamine restores tight junction organization after disruption by a conventional peritoneal dialysis fluid

Understanding and targeting the molecular basis of peritoneal solute and protein transport is essential to improve peritoneal dialysis (PD) efficacy and patient outcome. Supplementation of PD fluids (PDF) with alanyl-glutamine (AlaGln) increased small solute transport and reduced peritoneal protein loss in a recent clinical trial. Transepithelial resistance and 10 kDa and 70 kDa dextran transport were measured in primary human endothelial cells (HUVEC) exposed to conventional acidic, glucose degradation products (GDP) containing PDF (CPDF) and to low GDP containing PDF (LPDF) with and without AlaGln. Zonula occludens-1 (ZO-1) and claudin-5 were quantified by Western blot and immunofluorescence and in mice exposed to saline and CPDF for 7 weeks by digital imaging analyses. Spatial clustering of ZO-1 molecules was assessed by single molecule localization microscopy. AlaGln increased transepithelial resistance, and in CPDF exposed HUVEC decreased dextran transport rates and preserved claudin-5 and ZO-1 abundance. Endothelial clustering of membrane bound ZO-1 was higher in CPDF supplemented with AlaGln. In mice, arteriolar endothelial claudin-5 was reduced in CPDF, but restored with AlaGln, while mesothelial claudin-5 abundance was unchanged. AlaGln supplementation seals the peritoneal endothelial barrier, and when supplemented to conventional PD fluid increases claudin-5 and ZO-1 abundance and clustering of ZO-1 in the endothelial cell membrane. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

J. Biol. Chem.

Ubiquitous calpains (mu- and m-calpain) have been repeatedly implicated in apoptosis, but the underlying mechanism(s) remain(s) to be elucidated. We examined ionomycin-induced cell death in LCLC 103H cells, derived from a human large cell lung carcinoma. We detected hallmarks of apoptosis such as membrane blebbing, nuclear condensation, DNA ladder formation, caspase activation, and poly-(ADP-ribose)polymerase cleavage. Apoptosis was prevented by preincubation of the cells with the calpain inhibitor acetyl-calpastatin 27-peptide and the caspase inhibitor Z-DEVD-fmk, implicating both the calpains and caspases in the apoptotic process. The apoptotic events correlated in a calpastatin-inhibitable manner with Bid and Bcl-2 decrease and with activation of caspases-9, -3, and -7. In vitro both ubiquitous calpains cleaved recombinant Bcl-2, Bid, and Bcl-X-L at single sites truncating their N-terminal regions. Binding studies revealed diminished interactions of calpain-truncated Bcl-2 and Bid with immobilized intact Bcl-2 family proteins. Moreover, calpain-cleaved Bcl-2 and Bid induced cytochrome c release from isolated mitochondria. We conclude that ionomycin-induced calpain activation promotes decrease of Bcl-2 proteins thereby triggering the intrinsic apoptotic pathway