Relationship between lactate and glutamine metabolism in vitro by the kidney: Differences between dog and rat and importance of alanine synthesis in the dog

Relationship between lactate and glutamine metabolism in vitro by the kidney: Differences between dog and rat and importance of alanine synthesis in the dog. Interaction between lactate (1 or 5 mM) and glutamine (1 or 5 mM) metabolism was studied with renal cortical slices incubated at a pH of 7.0 and obtained from acidotic (ammonium chloride) dogs and rats. The effect of amino-oxyacetate (0.2 mM), dichloroacetate (3 mM), and fluoroacetate (0.05 mM) was also studied. Significant differences were observed between dog and rat. In the dog, lactate had no effect on glutamine uptake and vice versa, but gluconeogenesis increased. Ammonia production, however, decreased by 13 to 21%, whereas a significant increase in alanine production was noted. In the rat, glutamine extraction and ammonia production dropped by 33% with 5 mM lactate. In contrast to the observation in the dog, no production of alanine was noted, but significant accumulation of glutamate took place. Amino-oxyacetate inhibited alanine production in the dog and reestablished ammoniagenesis, and it led to a marked decrement in the uptake of lactate and glucose production in both species. Dichloroacetate in the dog resulted in a reduction in pyruvate, alanine, glucose, and ammonia production while glutamate accumulation was observed. In both species, fluoroacetate stimulated glutamine uptake and ammonia production. With lactate alone, fluoroacetate decreased lactate uptake and glucose production. With both lactate and glutamine in the medium, fluoroacetate prevented any effect of lactate on ammoniagenesis. The present study demonstrates that lactate has a modest depressing effect on renal ammonia production by dog slices through increased synthesis of alanine and redistribution of nitrogen from glutamine. In the rat, the depressing effect of lactate on ammonia production in the alanine aminotransferase deficient kidney occurs through accumulation of glutamate. The data also reveal that oxidation of lactate to carbon dioxide is greater in the dog than it is in the rat, but that gluconeogenesis from lactate is more important in the rat.Relations entre les métabolismes du lactate et de la glutamine in vitro par le rein: Différences entre le chien et le rat et importance de la synthèse d'alanine chez le chien. L'interaction entre le métabolisme du lactate (1 ou 5 mM) et celui de la glutamine (1 ou 5 mM) a été étudiée sur des tranches de cortex rénal incubées à pH 7,0 et obtenues à partir de chiens ou de rats en acidose. L'effet de l'amino-oxyacétate (0,2 mM), du dichloroacétate (3 mM) et du fluoroacétate (0,05 mM) a aussi été étudié. Des différences significatives entre le rat et le chien ont été observées. Chez le chien, le lactate n'a pas d'effet sur la captation de glutamine, et réciproquement, mais la gluconéogenèse augmente. Cependant la production d'ammoniaque est diminuée de 13 à 21% alors qu'une augmentation significative de la production d'alanine est observée. Chez le rat, l'extraction de la glutamine et la production d'ammoniaque diminuent de 33% avec le lactate 5 mM. A l'opposé de ce qui est constaté chez le chien, il n'est pas observé de production d'alanine mais une accumulation significative de glutamate. L'amino-oxyacétate inhibe la production d'alanine chez le chien et restaure l'ammoniogenèse, cependant qu'il détermine une diminution importante de la captation de lactate et de la production de glucose dans les deux espèces. Le dichloroacétate a pour conséquence, chez le chien, une diminution de la production de pyruvate, d'alanine, de glucose et d'ammoniaque, cependant qu'une accumulation de glutamate est observée. Dans les deux espèces le fluoroacétate stimule la captation de glutamine et la production d'ammoniaque. Avec le lactate seul, le fluoroacétate diminue la captation de lactate et la production de glucose. Quand à la fois du lactate et de la glutamine sont ajoutés au milieu, le fluoroacétate empêche les effets du lactate sur l'ammoniogenèse. Ce travail démontre que le lactate a un effet dépresseur modeste sur la production rénale d'ammoniaque par les tranches de rein chez le chien par l'intermédiaire d'une augmentation de la synthèse de l'alanine et de la redistribution de l'azote à partir de la glutamine. Chez le rat, l'effet dépresseur du lactate sur la production d'ammoniaque dans le rein privé d'alanine amino-transférase s'exerce au moyen d'une accumulation de glutamate. Ces résultats révèlent que l'oxydation du lactate en CO2 est plus importante chez le chien que chez le rat alors que la gluconéogenèse à partir du lactate est plus importante chez le rat

The interaction between the measles virus nucleoprotein and the Interferon Regulator Factor 3 relies on a specific cellular environment

<p>Abstract</p> <p>Background</p> <p>The genome of measles virus consists of a non-segmented single-stranded RNA molecule of negative polarity, which is encapsidated by the viral nucleoprotein (N) within a helical nucleocapsid. The N protein possesses an intrinsically disordered C-terminal domain (aa 401–525, N_TAIL) that is exposed at the surface of the viral nucleopcapsid. Thanks to its flexible nature, N_TAILinteracts with several viral and cellular partners. Among these latter, the Interferon Regulator Factor 3 (IRF-3) has been reported to interact with N, with the interaction having been mapped to the regulatory domain of IRF-3 and to N_TAIL. This interaction was described to lead to the phosphorylation-dependent activation of IRF-3, and to the ensuing activation of the pro-immune cytokine RANTES gene.</p> <p>Results</p> <p>After confirming the reciprocal ability of IRF-3 and N to be co-immunoprecipitated in 293T cells, we thoroughly investigated the N_TAIL-IRF-3 interaction using a recombinant, monomeric form of the regulatory domain of IRF-3. Using a large panel of spectroscopic approaches, including circular dichroism, fluorescence spectroscopy, nuclear magnetic resonance and electron paramagnetic resonance spectroscopy, we failed to detect any direct interaction between IRF-3 and either full-length N or N_TAILunder conditions where these latter interact with the C-terminal X domain of the viral phosphoprotein. Furthermore, such interaction was neither detected in <it>E. coli </it>nor in a yeast two hybrid assay.</p> <p>Conclusion</p> <p>Altogether, these data support the requirement for a specific cellular environment, such as that provided by 293T human cells, for the N_TAIL-IRF-3 interaction to occur. This dependence from a specific cellular context likely reflects the requirement for a human or mammalian cellular co-factor.</p

Present eternity : quests of temporality in the literary production of the &quot;extr&#234;me contemporain&quot; in France (The Writings of Dominique Fourcade and Emmanuel Hocquard)

The term \uab extr\ueame contemporain \ubb is an expression currently used by scholars to indicate the French literary production of the last 20 years. This term was used in a work of literature for the first time by the French poet Dominique Fourcade in 1986 (\uc9l\ue9gie L apostrophe E.C.) in reference to an epoch, but also to a new sense of experiencing time and space in the so-called \uab age of digital reproducibility \ubb. The aim of this paper is to consider how the change in temporal protocols due to the triumph of Big Optics (Paul Virilio) affects the sense of teleology (destiny) and the quest for experience in French contemporary poetry (in particular, in the genre of the elegy). Including both memory and anticipation, the \uab extr\ueame contemporain \ubb production seems to prefer the \u201ctime of now\u201d, Jetz-zeit in Benjamin\u2019s words, to past or testimony, and speaks to the present, whose responsibility is to give voice to a space where everything is simply allowed to happen

Probing structural transitions in both structured and disordered proteins using site-directed spin-labeling EPR spectroscopy

International audienc

Amplitude of pancreatic lipase lid opening in solution and identification of spin label conformational subensembles by combining continuous wave and pulsed EPR spectroscopy and molecular dynamics.

International audienceThe opening of the lid that controls the access to the active site of human pancreatic lipase (HPL) was measured from the magnetic interaction between two spin labels grafted on this enzyme. One spin label was introduced at a rigid position in HPL where an accessible cysteine residue (C181) naturally occurs. A second spin label was covalently bound to the mobile lid after introducing a cysteine residue at position 249 by site-directed mutagenesis. Double electron-electron resonance (DEER) experiments allowed the estimation of a distance of 19 +/- 2 A between the spin labels when bilabeled HPL was alone in a frozen solution, i.e., with the lid in the closed conformation. A magnetic interaction was however detected by continuous wave EPR experiments, suggesting that a fraction of bilabeled HPL contained spin labels separated by a shorter distance. These results could be interpreted by the presence of two conformational subensembles for the spin label lateral chain at position 249 when the lid was closed. The existence of these conformational subensembles was revealed by molecular dynamics experiments and confirmed by the simulation of the EPR spectrum. When the lid opening was induced by the addition of bile salts and colipase, a larger distance of 43 +/- 2 A between the two spin labels was estimated from DEER experiments. The distances measured between the spin labels grafted at positions 181 and 249 were in good agreement with those estimated from the known X-ray structures of HPL in the closed and open conformations, but for the first time, the amplitude of the lid opening was measured in solution or in a frozen solution in the presence of amphiphiles

Small-area geographic and socioeconomic inequalities in colorectal tumour detection in France

IF 2.415International audienceThe aim of this study was to assess the impact of area deprivation and primary care facilities on colorectal adenoma detection and on colorectal cancer (CRC) incidence in a French well-defined population before mass screening implementation. The study population included all patients aged 20 years or more living in Cote d'Or (France) with either colorectal adenoma or invasive CRC first diagnosed between 1995 and 2002 and who were identified from the Burgundy Digestive Cancer Registry and the Cote d'Or Polyp Registry. Area deprivation was assessed using the European deprivation index on the basis of the smallest French area available (Ilots Regroupes pour l'Information Statistique). Healthcare access was assessed using medical density of general practitioners (GPs) and road distance to the nearest GP and gastroenterologist. Bayesian regression analyses were used to estimate influential covariates on adenoma detection and CRC incidence rates. The results were expressed as relative risks (RRs) with their 95% credibility interval. In total, 5399 patients were diagnosed with at least one colorectal adenoma and 2125 with invasive incident CRC during the study period. Remoteness from GP [RR=0.71 (0.61-0.83)] and area deprivation [RR=0.98 (0.96-1.00)] independently reduced the probability of adenoma detection. CRC incidence was only slightly affected by GP medical density [RR=1.05 (1.01-1.08)] without any area deprivation effect [RR=0.99 (0.96-1.02)]. Distance to gastroenterologist had no impact on the rates of adenoma detection or CRC incidence. This study highlighted the prominent role of access to GPs in the detection of both colorectal adenomas and overall cancers. Deprivation had an impact only on adenoma detection