24 research outputs found

    Usage analytics: a process to extract and analyse usage data to understand user behaviour in cloud

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    Usage in the software field deals with knowledge about how end-users use the application and how the application responds to the users’ action. Understanding usage data can help developers optimise the application development process by prioritising the resources such as time, cost and man power on features of the application which are critical for the user. However, in a complex cloud computing environment, the process of extracting and analysing usage data is difficult since the usage data is spread across various front-end interfaces and back-end underlying infrastructural components of the cloud that host the application and are of different types and formats. In this paper, we propose usage analytics, a process to extract and analyse usage to understand the behavioural usage patterns of the user with the aim to identify features critical to user. We demonstrate how to identify the features in a cloud based application, how to extract and analyse the usage data to understand the user behaviour

    Fyn Mediates Leptin Actions in the Thymus of Rodents

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    BACKGROUND:Several effects of leptin in the immune system rely on its capacity to modulate cytokine expression and apoptosis in the thymus. Surprisingly, some of these effects are dependent on signal transduction through the IRS1/PI3-kinase, but not on the activation of JAK2. Since all the well known effects of leptin in different cell types and tissues seem to be dependent on JAK2 activation, we hypothesized that, at least for the control of thymic function, another, unknown kinase could mediate the transduction of the leptin signal from the ObR towards the IRS1/PI3-kinase signaling cascade. METHODOLOGY/PRINCIPAL FINDINGS:Here, by employing immunoblot, real-time PCR and flow citometry we show that the tyrosine kinase, Fyn, is constitutively associated with the ObR in thymic cells. Following a leptin stimulus, Fyn undergoes an activating tyrosine phosphorylation and a transient association with IRS1. All these effects are independent of JAK2 activation and, upon Fyn inhibition, the signal transduction towards IRS1/PI3-kinase is abolished. In addition, the inhibition of Fyn significantly modifies the effects of leptin on thymic cytokine expression. CONCLUSION/SIGNIFICANCE:Therefore, in the thymus, Fyn acts as a tyrosine kinase that transduces the leptin signal independently of JAK2 activation, and mediates some of the immunomodulatory effects of leptin in this tissue

    DAF-16 and Δ9 Desaturase Genes Promote Cold Tolerance in Long-Lived Caenorhabditis elegans age-1 Mutants

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    In Caenorhabditis elegans, mutants of the conserved insulin/IGF-1 signalling (IIS) pathway are long-lived and stress resistant due to the altered expression of DAF-16 target genes such as those involved in cellular defence and metabolism. The three Δ9 desaturase genes, fat-5, fat-6 and fat-7, are included amongst these DAF-16 targets, and it is well established that Δ9 desaturase enzymes play an important role in survival at low temperatures. However, no assessment of cold tolerance has previously been reported for IIS mutants. We demonstrate that long-lived age-1(hx546) mutants are remarkably resilient to low temperature stress relative to wild type worms, and that this is dependent upon daf-16. We also show that cold tolerance following direct transfer to low temperatures is increased in wild type worms during the facultative, daf-16 dependent, dauer stage. Although the cold tolerant phenotype of age-1(hx546) mutants is predominantly due to the Δ9 desaturase genes, additional transcriptional targets of DAF-16 are also involved. Surprisingly, survival of wild type adults following a rapid temperature decline is not dependent upon functional daf-16, and cellular distributions of a DAF-16::GFP fusion protein indicate that DAF-16 is not activated during low temperature stress. This suggests that cold-induced physiological defences are not specifically regulated by the IIS pathway and DAF-16, but expression of DAF-16 target genes in IIS mutants and dauers is sufficient to promote cross tolerance to low temperatures in addition to other forms of stress

    Melanin-concentrating hormone induces insulin resistance through a mechanism independent of body weight gain

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    Transgenic hyperexpression of melanin-concentrating hormone (MCH) produces a phenotype of obesity and glucose intolerance. However, it is not known whether under this specific condition, glucose intolerance develops as a direct consequence of hyperexpressed MCH or is secondary to increased adiposity. Here, rats were treated i.c.v. with MCH or with an antisense oligonucleotide to MCH (MCH-ASO). MCH promoted an increase in blood glucose and a decrease in blood insulin levels during a glucose tolerance test. MCH also caused a decrease in the constant of glucose disappearance during an insulin tolerance test. All these effects of MCH were independent of body weight variation and were accompanied by reduced insulin receptor substrate (IRS)-1 engagement of phosphatidylinositol-3 kinase (P13-kinase) in white and brown adipose tissues, skeletal muscle and liver and by reduced Akt activation in skeletal muscle. MCH also led to a significant reduction in ERK activation in white adipose tissue. Finally, inhibition of hypothalamic MCH expression promoted a significant increase in ERK activation in brown adipose tissue. We conclude that hypothalamic MCH controls glucose homeostasis through mechanisms that are, at least in part, independent of adiposity.186119320

    beta 3-Adrenergic-dependent and -independent mechanisms participate in cold-induced modulation of insulin signal transduction in brown adipose tissue of rats

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    During cold exposure, homeothermic animals mobilize glucose with higher efficiency than at thermoneutrality. An interaction between the insulin signal transduction machinery and high sympathetic tonus is thought to play an important role in this phenomenon. In the present study, rats were exposed to cold during 8 days and treated, or not, with a beta3-adrenergic agonist, BRL37344 sodium 4-2-2-(3- chlorophenyl)-2-hydroxyethyl amino propyl phenoxy-acetic acid sodium ( BRL37344), or antagonist, SR59230A3-(2- ethylphenoxy)[( 1S)-1,2,3,4-tetrahydronaphth-1-ylamino]-(2S)- 2-propanol oxalate (SR59230A), to evaluate the cross-talk between insulin and beta3-adrenergic intracellular signaling in brown adipose tissue. The drugs did not modify food ingestion, body temperature, and body weight in control and cold-exposed rats. Treatment of control rats with BRL37344 led to higher insulin-induced tyrosine phosphorylation of the insulin receptors, insulin receptor substrate (IRS)-1 and ERK, higher insulin-induced IRS1/ PI3-kinase association, and higher [ Ser(473)] phosphorylation of Akt. Cold exposure alone promoted higher insulin-induced tyrosine phosphorylation of the insulin receptors, IRS-1, IRS-2, and ERK, and higher insulin-induced IRS-1 and IRS-2/PI3-kinase association. Except for the regulation of ERK, SR59230A abolished all the cold-induced effects upon the insulin signal transduction pathway. However, this antagonist only partially inhibited the cold-induced increase of glucose uptake. Thus, the sympathetic tonus generated during cold-exposure acts, in brown adipose tissue, through the beta3-adrenergic receptor and modulates insulin signal transduction, with the exception of ERK. However, insulin-independent mechanisms other than beta3-adrenergic activation participate in cold-induced glucose uptake in brown adipose tissue of rats.449653754

    Peroxisome proliferator-activated receptor gamma coactivator-1-dependent uncoupling protein-2 expression in pancreatic islets of rats: a novel pathway for neural control of insulin secretion

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    Aims/hypothesis. Sympathetic inputs inhibit insulin secretion through alpha2-adrenergic receptors coupled with Gi protein. High adrenergic tonus generated by exposure of homeothermic animals to cold reduces insulin secretion. In this study we evaluate the participation of UCP-2 in cold-induced regulation of insulin secretion. Methods. Static insulin secretion studies, western blotting and immunohistochemistry were used in this investigation. Results. Exposure of rats to cold during 8 days promoted 60% (n=15, p<0.05) reduction of basal serum insulin levels concentration accompanied by reduction of the area under insulin curve during i.p. GTT (50%, n=15, p<0.05). Isolated islets from cold-exposed rats secreted 57% (n=6, p<0.05) less insulin following a glucose challenge. Previous sympathectomy, partially prevented the effect of cold exposure upon insulin secretion. Islets isolated from cold-exposed rats expressed 51% (n=6, p<0.5) more UCP-2 than islets from control rats, while the inhibition of UCP-2 expression by antisense oligonucleotide treatment partially restored insulin secretion of islets obtained from cold-exposed rats. Cold exposure also induced an increase of 69% (n=6, p<0.05) in PGC-1 protein content in pancreatic islets. Inhibition of islet PGC-1 expression by antisense oligonucleotide abrogated cold-induced UCP-2 expression and partially restored insulin secretion in islets exposed to cold. Conclusion/interpreatation. Our data indicate that sympathetic tonus generated by exposure of rats to cold induces the expression of PGC-1, which participates in the control of UCP-2 expression in pancreatic islets. Increased UCP-2 expression under these conditions could reduce the beta-cell ATP/ADP ratio and negatively regulate insulin secretion.46111522153

    Cold-induced PGC-1 alpha expression modulates muscle glucose uptake through an insulin receptor/Akt-independent, AMPK-dependent pathway

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    Peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) participates in control of expression of genes involved in adaptive thermogenesis, muscle fiber type differentiation, and fuel homeostasis. The objective of the present study was to evaluate the participation of cold-induced PGC-1alpha expression in muscle fiber type-specific activity of proteins that belong to the insulin-signaling pathway. Rats were exposed to 4degreesC for 4 days and acutely treated with insulin in the presence or absence of an antisense oligonucleotide to PGC-1alpha. Cold exposure promoted a significant increase of PGC-1alpha and uncoupling protein-3 protein expression in type I and type II fibers of gastrocnemius muscle. In addition, cold exposure led to higher glucose uptake during a hyperinsulinemic clamp, which was accompanied by higher expression and membrane localization of GLUT4 in both muscle fiber types. Cold exposure promoted significantly lower insulin-induced tyrosine phosphorylation of the insulin receptor (IR) and Ser(473) phosphorylation of acute transforming retrovirus thymoma (Akt) and an insulin-independent increase of Thr(172) phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). Inhibition of PGC-1alpha expression in cold-exposed rats by antisense oligonucleotide treatment diminished glucose clearance rates during a hyperinsulinemic clamp and reduced expression and membrane localization of GLUT4. Reduction of PGC-1alpha expression resulted in no modification of insulin-induced tyrosine phosphorylation of the IR and Ser(473) phosphorylation of Akt. Finally, reduction of PGC-1alpha resulted in lower Thr(172) phosphorylation of AMPK. Thus cold-induced hyperexpression of PGC-1alpha participates in control of skeletal muscle glucose uptake through a mechanism that controls GLUT4 expression and subcellular localization independent of the IR and Akt activities but dependent on AMPK.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.2874E686E69

    Novel signal transduction pathway for luteinizing hormone and its interaction with insulin: Activation of janus kinase/signal transducer and activator of transcription and phosphoinositol 3-kinase/akt pathways

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    The actions of LH are mediated through a single class of cell surface LH/human chorionic gonadotropin receptor, which is a member of the G protein-coupled receptor family. In the present study we showed that LH induced rapid tyrosine phosphorylation and activation of the Janus kinase 2 (JAK2) in rat ovary. Upon JAK2 activation, tyrosine phosphorylation of signal transducer and activator of transcription-1 (STAT-1), STAT-5b, insulin receptor substrate-1 (IRS-1), and Src homology and collagen homology (Shc) were detected. In addition, LH induced IRS-1/phosphoinositol 3-kinase and Shc/growth factor receptor-binding protein 2 (Grb2) associations and downstream AKT (protein kinase B, homologous to v-AKT) serine phosphorylation and ERK tyrosine phosphorylation, respectively. The simultaneous infusion of insulin and LH induced higher phosphorylation levels of JAK2, STAT5b, IRS-1, and AKT compared with each hormone alone in the whole ovary of normal rats. By immunohistochemistry we demonstrated that these late events take place in follicular cells and both external and internal theca. These results indicate a new signal transduction pathway for LH and show that there is positive cross-talk between the insulin and LH signaling pathways at the level of phosphoinositol 3-kinase/AKT pathway in this tissue.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.144263864
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