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81.
Xavier Fioramonti Adam Deak Srinidhi Deshpande Lionel Carneiro Chunxue Zhou Nazish Sayed Branly Orban Joshua R. Berlin Luc Pénicaud Corinne Leloup Annie Beuve Vanessa H. Routh 《PloS one》2013,8(7)
Aims
Hypoglycemia is a severe side effect of intensive insulin therapy. Recurrent hypoglycemia (RH) impairs the counter-regulatory response (CRR) which restores euglycemia. During hypoglycemia, ventromedial hypothalamus (VMH) production of nitric oxide (NO) and activation of its receptor soluble guanylyl cyclase (sGC) are critical for the CRR. Hypoglycemia also increases brain reactive oxygen species (ROS) production. NO production in the presence of ROS causes protein S-nitrosylation. S-nitrosylation of sGC impairs its function and induces desensitization to NO. We hypothesized that during hypoglycemia, the interaction between NO and ROS increases VMH sGC S-nitrosylation levels and impairs the CRR to subsequent episodes of hypoglycemia. VMH ROS production and S-nitrosylation were quantified following three consecutive daily episodes of insulin-hypoglycemia (RH model). The CRR was evaluated in rats in response to acute insulin-induced hypoglycemia or via hypoglycemic-hyperinsulinemic clamps. Pretreatment with the anti-oxidant N-acetyl-cysteine (NAC) was used to prevent increased VMH S-nitrosylation.Results
Acute insulin-hypoglycemia increased VMH ROS levels by 49±6.3%. RH increased VMH sGC S-nitrosylation. Increasing VMH S-nitrosylation with intracerebroventricular injection of the nitrosylating agent S-nitroso-L-cysteine (CSNO) was associated with decreased glucagon secretion during hypoglycemic clamp. Finally, in RH rats pre-treated with NAC (0.5% in drinking water for 9 days) hypoglycemia-induced VMH ROS production was prevented and glucagon and epinephrine production was not blunted in response to subsequent insulin-hypoglycemia.Conclusion
These data suggest that NAC may be clinically useful in preventing impaired CRR in patients undergoing intensive-insulin therapy. 相似文献82.
Cyrille Gavazzi Catherine Isel Emilie Fournier Vincent Moules Annie Cavalier Daniel Thomas Bruno Lina Roland Marquet 《Nucleic acids research》2013,41(2):1241-1254
The genome of influenza A viruses (IAV) is split into eight viral RNAs (vRNAs) that are encapsidated as viral ribonucleoproteins. The existence of a segment-specific packaging mechanism is well established, but the molecular basis of this mechanism remains to be deciphered. Selective packaging could be mediated by direct interaction between the vRNA packaging regions, but such interactions have never been demonstrated in virions. Recently, we showed that the eight vRNAs of a human H3N2 IAV form a single interaction network in vitro that involves regions of the vRNAs known to contain packaging signals in the case of H1N1 IAV strains. Here, we show that the eight vRNAs of an avian H5N2 IAV also form a single network of interactions in vitro, but, interestingly, the interactions and the regions of the vRNAs they involve differ from those described for the human H3N2 virus. We identified the vRNA sequences involved in five of these interactions at the nucleotide level, and in two cases, we validated the existence of the interaction using compensatory mutations in the interacting sequences. Electron tomography also revealed significant differences in the interactions taking place between viral ribonucleoproteins in H5N2 and H3N2 virions, despite their canonical ‘7 + 1’ arrangement. 相似文献
83.
Andrew D. Cox Frank St. Michael Annie Aubry Chantelle M. Cairns Philippa C. R. Strong Alexander C. Hayes Susan M. Logan 《Glycoconjugate journal》2013,30(9):843-855
A lipoteichoic acid has recently been shown to be conserved in the majority of strains from Clostridium difficile and as such is being considered as a possible vaccine antigen. In this study we examine the candidacy of the conserved lipoteichoic acid by demonstrating that it is possible to elicit antibodies against C. difficile strains following immunisation of rabbits and mice with glycoconjugates elaborating the conserved lipoteichoic acid antigen. The present study describes a conjugation strategy that utilises an amino functionality, present at approximately 33 % substitution of the N-acetyl-glucosamine residues within the LTA polymer repeating unit, as the attachment point for conjugation. A maleimide-thiol linker strategy with the maleimide linker on the carboxyl residues of the carrier protein and the thiol linker on the carbohydrate was employed. Immunisation derived antisera from rabbits and mice, recognised all strains of C. difficile vegetative cells examined, despite an immune response to the linkers also being observed. These sera recognised live cells in an immunofluorescence assay and were also able to recognise the spore form of the bacterium. This study has illustrated that the LTA polymer is a highly conserved surface polymer of C. difficile that is easily accessible to the immune system and as such merits consideration as a vaccine antigen to combat C. difficile infection. 相似文献
84.
Jesu Arockiaraj Annie J. Gnanam Rajesh Palanisamy Venkatesh Kumaresan Prasanth Bhatt Muthukumaresan Kuppusamy Thirumalai Arpita Roy Mukesh Pasupuleti Marimuthu Kasi Akila Sathyamoorthi Abirami Arasu 《Biochimie》2013
In this study, we report the bioinformatics characterization, gene expression, transglutaminase activity and coagulation assays of transglutaminase (TGase) of freshwater prawn Macrobrachium rosenbergii identified from the constructed cDNA library by GS FLX™ technology. Even though, TGase have sequence similarity, they differ extensively in their substrate specificity and are thought to play an important in variety of functions such as development, tissue differentiation and immune responses etc. Gene expression studies show that MrTGase is widely distributed in the tissues such as heart, muscle, intestine, brain, etc., but higher amounts are found in hemocyte. Results of TGase mRNA relative expression in hemocyte, before and after infected with white spot syndrome baculovirus (WSBV) and Vibrio harveyi show that the gene expression initially increases up to 24 h and then it falls down. Coagulation assay results showed that the endogenous TGase is involved in the rapid assembly of a specific, plasma clotting protein. Structural studies show that MrTGase contains a typical TGc domain between 323 and 424, and two putative integrin-binding motifs at Arg180–Gly181–Asp182 and Arg269–Gly270–Asp271. The predicted 3D model of MrTGase contains 47.04% coils (366 amino acid residues), 26.74% extended strand (208 residues), 21.72% α-helix (169 residues) and 4.5% beta turns (35 residues). BLASTp analysis of MrTGase exhibited high sequence similarities with other crustacean TGase, with the highest observed in white shrimp (77.1%). Moreover, the phylogenetic analysis also showed that MrTGase clustered with the other members of crustacean TGase. Overall, these results suggested that MrTGase is a major and functional TGase of M. rosenbergii for haemolymph coagulation and also in spread of infection. 相似文献
85.
Abderrahim Rahmouni Jean-Marc Malinge Annie Schwartz Marc Leng 《Journal of biomolecular structure & dynamics》2013,31(2):363-375
Abstract The importance of the base composition and of the conformation of nucleic acids in the reaction with the drug cis-diamminedichloroplatinum(II) has been studied by competition experiments between the drug and several double-stranded polydeoxyribonucleotides. Binding to poly(dG)·poly(dC) is larger than to poly (dG-dC)·poly(dG-dC). There is no preferential binding in the competition between poly(dG-dC) ·poly(dG-dC), poly(dA-dC) ·poly(dG-dT) and poly(dA-dG)·poly(dC-dT). In the competition between poly(dG-dC) ·poly (dG-dC) (B conformation) and poly(dG-br5dC) ·poly(dG-br5dC) (Z conformation), the drug binds equally well to both polynucleotides. In natural DNA, modification of guanine residues in (GC)n·(GC)nsequences by the drug has been revealed by the inhibition of cleavage of these sequences by the restriction enzyme BssHII. By means of antibodies to platinated poly(dG-dC), it is shown that some of the adducts formed in platinated poly(dG-dC) are also formed in platinated pBR322 DNA. The type of adducts recognized by the antibodies is not known. Thin layer chromatography of the products after chemical and enzymatic hydrolysis of platinated poly(dG-dC) suggests that interstrand cross-links are formed. Finally, the conformations of poly(dG-m5dC) modified either by cis-diamminedichloroplatinum(II) or by trans-diammine- dichloroplatinum(II) have been compared by circular dichroism. Both the cis-isomer and the trans-isomer stabilize the Z conformation when they bind to poly(dG-m5dC) in the Z conformation. When they bind to poly(dG-m5dC) in the B conformation, the conformations of poly(dG-m5dC) modified by the cis or the trans-isomer are different. Moreover, the cis-isomer facilitates the B form-Z form transition of the unplatinated regions while the trans-isomer makes it more difficult. 相似文献
86.
Low temperature constrains growth rates but not short-term ingestion rates of Antarctic ciliates 总被引:1,自引:0,他引:1
Julie M. Rose Elizabeth Fitzpatrick Annie Wang Rebecca J. Gast David A. Caron 《Polar Biology》2013,36(5):645-659
Low environmental temperature is a major factor affecting the feeding activities, growth rates, and growth efficiencies of metazooplankton, but these features are poorly characterized for most protistan species. Laboratory experiments were conducted to examine the growth and ingestion rates of cultured herbivorous Antarctic ciliates. Three ciliates fed several algal species individually at 0 °C exhibited uniformly low growth rates (<0.26 day?1), but the algae varied substantially in their ability to support ciliate growth. Specific ingestion rate (prey biomass consumed per unit ciliate biomass per unit time) was strongly affected by ciliate physiological state (starved vs. actively growing). Starved cells ingested many more prey than cells in balanced growth during short-term (minutes-to-hours) experiment but did not grow faster, indicating temperature compensation of ingestion rate but not growth rate. Field experiments were also conducted in the Ross Sea, Antarctica, to characterize the feeding rates of ciliates in natural plankton assemblages. Specific ingestion rates of two dominant ciliates were an order of magnitude lower than rates reported for temperate ciliates, but estimated rates were strongly affected by prey abundance. Our data indicate that short-term ingestion rates of Antarctic ciliates were not constrained by low environmental temperature although overall growth rates were, indicating the need for caution when designing experiments to measure the ingestion rates of these species at low environmental temperature. We present evidence that artifacts arising from estimating ingestion in short-term experiments may lead to errors in estimating feeding impact and growth efficiencies that are particularly large for polar protists. 相似文献
87.
Annie J. Valuska Katherine A. Leighty Gina M. Ferrie Valerie D. Nichols Cheryl L. Tybor Chelle Plassé Tamara L. Bettinger 《Zoo biology》2013,32(2):216-221
Mixed‐species exhibits offer a variety of benefits but can be challenging to maintain due to difficulty in managing interspecific interactions. This is particularly true when little has been documented on the behavior of the species being mixed. This was the case when we attempted to house three species of turaco (family: Musophagidae) together with other species in a walk‐through aviary. To learn more about the behavior of great blue turacos, violaceous turacos, and white‐bellied gray go‐away birds, we supplemented opportunistic keeper observations with systematic data collection on their behavior, location, distance from other birds, and visibility to visitors. Keepers reported high levels of aggression among turacos, usually initiated by a go‐away bird or a violaceous turaco. Most aggression occurred during feedings or when pairs were defending nest sites. Attempts to reduce aggression by temporarily removing birds to holding areas and reintroducing them days later were ineffective. Systematic data collection revealed increased social behavior, including aggression, during breeding season in the violaceous turacos, as well as greater location fidelity. These behavioral cues may be useful in predicting breeding behavior in the future. Ultimately, we were only able to house three species of turaco together for a short time, and prohibitively high levels of conflict occurred when pairs were breeding. We conclude that mixing these three turaco species is challenging and may not be the most appropriate housing situation for them, particularly during breeding season. However, changes in turaco species composition, sex composition, or exhibit design may result in more compatible mixed‐turaco species groups. Zoo Biol. 32:216–221, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
88.
Annie Bouchard-Mercier Iwona Rudkowska Simone Lemieux Patrick Couture Marie-Claude Vohl 《Journal of lipid research》2013,54(10):2866-2873
Interindividual variability in the response of plasma triglyceride concentrations (TG) following fish oil consumption has been observed. Our objective was to examine the associations between single-nucleotide polymorphisms (SNPs) within genes encoding proteins involved in de novo lipogenesis and the relative change in plasma TG levels following a fish oil supplementation. Two hundred and eight participants were recruited in the greater Quebec City area. The participants completed a six-week fish oil supplementation (5 g fish oil/day: 1.9–2.2 g eicosapentaenoic acid and 1.1 g docosahexaenoic acid. SNPs within SREBF1, ACLY, and ACACA genes were genotyped using TAQMAN methodology. After correction for multiple comparison, only two SNPs, rs8071753 (ACLY) and rs1714987 (ACACA), were associated with the relative change in plasma TG concentrations (P = 0.004 and P = 0.005, respectively). These two SNPs explained 7.73% of the variance in plasma TG relative change following fish oil consumption. Genotype frequencies of rs8071753 according to the TG response groups (responders versus nonresponders) were different (P = 0.02). We conclude that the presence of certain SNPs within genes, such as ACLY and ACACA, encoding proteins involved in de novo lipogenesis seem to influence the plasma TG response following fish oil consumption. 相似文献
89.
Aims
Acute ethanol intoxication (AEI) attenuates the arginine vasopressin (AVP) response to hemorrhage leading to impaired hemodynamic counter-regulation and accentuated hemodynamic stability. Previously we identified that the ethanol-induced impairment of circulating AVP concentrations in response to hemorrhage was the result of augmented central nitric oxide (NO) inhibition. The aim of the current study was to examine the mechanisms underlying ethanol-induced up-regulation of paraventricular nucleus (PVN) NO concentration. Angiotensin (ANG) (1-7) is an important mediator of NO production through activation of the Mas receptor. We hypothesized that Mas receptor inhibition would decrease central NO concentration and thus restore the rise in circulating AVP levels during hemorrhagic shock in AEI rats.Main methods
Conscious male Sprague–Dawley rats (300–325 g) received a 15 h intra-gastric infusion of ethanol (2.5 g/kg + 300 mg/kg/h) or dextrose prior to a fixed-pressure (~ 40 mm Hg) 60 min hemorrhage. The Mas receptor antagonist A-779 was injected through an intracerebroventricular (ICV) cannula 15 min prior to hemorrhage.Key findings
PVN NOS activity and NO were significantly higher in AEI compared to DEX-treated controls at the completion of hemorrhage. ICV A-779 administration decreased NOS activity and NO concentration, partially restoring the rise in circulating AVP level at completion of hemorrhage in AEI rats.Significance
These results suggest that Mas receptor activation contributes to the NO-mediated inhibitory tone of AVP release in the ethanol-intoxicated hemorrhaged host. 相似文献90.
Gert Van Hoof Marisa Vieira Maria Gausman Annie Weisbrod 《The International Journal of Life Cycle Assessment》2013,18(8):1568-1580