Effect of a tissue oxygenator (almitrine + raubasine) on the metabolism of 2,3-diphosphoglycerate of rabbits submitted by hypoxia

In normoxic rabbits, the intravenous injection (1 mg/kg) of the product (almitrine + raubasine) do not modify the erythrocytic level of 2,3-DPG. But, after hypoxia (the rabbits being submitted to an oxygen pressure of 7,8 kPa during 20 minutes) the same dose of this product induce a durable rise of erythrocytic 2,3-DPG level which remain, 24 hours latter, + 15% above normal.     

The absence of lymphoid CD8+ dendritic cell maturation in L-selectin-/- respiratory compartment attenuates antiviral immunity

Intratracheal instillation of L-selectin-deficient (L-Sel(-/-)) mice with an adenovirus 2 (Ad2) vector resulted in the lack of respiratory Ad2- or beta-galactosidase-specific CTLs with concomitant long-lived beta-galactosidase transgene expression in the lungs. The absence of Ag-specific CTLs was attributed to a deficiency in lymphoid CD11c(+)CD8(+) dendritic cells (DCs) in the lower respiratory lymph nodes (LRLNs). To enable L-Sel(-/-) CTL activity, cell-sorted L-Sel(-/-)CD8(+) T cells were cocultured with cell-sorted L-Sel(+/+)CD8(+) or CD8(-) DCs or L-Sel(-/-)CD8(-) DCs. Only the CD8(+) DCs restored CTL activity; L-Sel(-/-)CD8(-) DCs failed to support L-Sel(+/+) CTLs because these remained immature, lacking the ability to express costimulatory molecules CD40, CD80, or CD86. Although no lung CD8(+) DCs were detected, the DC environment remained suppressive in L-Sel(-/-) mice evident by the lack of CTL responses following adenoviral challenge with OVA in recipient L-Sel(-/-) adoptively transferred with OT-1 CD8(+) T cells. To assess whether the L-Sel(-/-)CD8(-) DCs could be induced into maturity, microbial stimulation studies were performed showing the failure of L-Sel(-/-) LRLN to make matured DCs. When L-Sel(-/-) mice were subjected in vivo to microbial activation before Ad2 vector dosing, CTL activity was restored stimulating the renewed presence of LRLN CD8(+) DCs in L-Sel(-/-) mice. These studies show that impairment of L-Sel(-/-) DC maturation results in insufficient mature DCs that require microbial activation to restore increases in respiratory CD8(+) DCs to support CTL responses.     

Tyrosine phosphorylation of myosin heavy chain during skeletal muscle differentiation: an integrated bioinformatics approach

Background  

Previously it has been shown that insulin-mediated tyrosine phosphorylation of myosin heavy chain is concomitant with enhanced association of C-terminal SRC kinase during skeletal muscle differentiation. We sought to identify putative site(s) for this phosphorylation event.     

Effect of Anionic Salt and Highly Fermentable Carbohydrate Supplementations on Urine pH and on Experimentally Induced Hypocalcaemia in Cows

The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1), the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2), control ration following a period with supplementation (3) and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4). Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets.     

Polypeptide tags,ubiquitous modifiers for plant protein regulation

Evidence has emerged over the past few years that plants, like animals and fungi, employ a variety of polypeptides as tags to reversibly or irreversibly affect the function, structure, location, and/or turnover of numerous intracellular proteins. In plants, known polypeptide tags include ubiquitin, SUMO, RUB, and APG12, with the possibility of others. These modifiers are typically added post-translationally using individual sets of conjugase pathways that attach the polypeptides via an isopeptide bond to -lysyl amino group(s) in the targets. Often the tags can be removed subsequently by unique proteases that specifically cleave only the isopeptide bond. Examples also exist where the tag is added during translation upon fusion of the coding sequence of the tag with that of the target. Based on the number and diversity of targets, ubiquitin is the most influential modifier which mainly serves as a reusable signal for selective protein degradation by the 26S proteasome. In contrast, SUMO, RUB and APG12 become attached to a more limited number of targets and appear to have specialized functions, including roles in nuclear pore assembly/function, cell-cycle regulation, and lysosomal/vacuole trafficking, respectively. Based on their widespread occurrence in plants and their pervasive role in various biological processes, polypeptide tags likely play a prominent role in plant cell regulation.