223 research outputs found
A Quantitative Spectrographic Study on the Effects of the Alkali Metals upon the Determination of Calcium
It has been known for some time that in spectrographic analysis each element present has some effect upon the other elements present. Our investigation of the effect of the alkali metals on calcium showed that, in general, the intensity of the spectral lines of calcium increased with an increase in the percentage of the alkali metal present. However, there is a decrease in the intensifying effect at the higher concentrations. The chlorides of the alkali metals used were in concentrations varying from 1.0 per cent to 0.031 per cent, and the concentrations of the calcium solutions used varied approximately over the same range. Slides were used to show the apparatus used (including the wedge sector), typical spectrograms, and also to show some of the data obtained in graphical form
Domain II of calmodulin is involved in activation of calcineurin
AbstractA family of mutant proteins related to calmodulin (CaM) has been produced using cDNA constructs in bacterial expression vectors. The new proteins contain amino acid substitutions in Ca2+-binding domains I, II, both I and II, or both II and IV. The calmodulin-like proteins have been characterized with respect to mobility on SDS-polyacrylamide gels, Ca2+-dependent enhancement of tyrosine fluorescence, and abilities to activate the CaM-dependent phosphatase calcineurin. These studies suggest that an intact Ca2+-binding domain II is minimally required for full activation of calcineurin
Bridging the Divide between Manual Gating and Bioinformatics with the Bioconductor Package flowFlowJo
In flow cytometry, different cell types are usually selected or âgatedâ by a series of 1- or 2-dimensional geometric subsets of the measurements made on each cell. This is easily accomplished in commercial flow cytometry packages but it is difficult to work computationally with the results of this process. The ability to retrieve the results and work with both them and the raw data is critical; our experience points to the importance of bioinformatics tools that will allow us to examine gating robustness, combine manual and automated gating, and perform exploratory data analysis. To provide this capability, we have developed a Bioconductor package called flowFlowJo that can import gates defined by the commercial package FlowJo and work with them in a manner consistent with the other flow packages in Bioconductor. We present this package and illustrate some of the ways in which it can be used
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Applications of Transport/Reaction Codes to Problems in Cell Modeling
We demonstrate two specific examples that show how our exiting capabilities in solving large systems of partial differential equations associated with transport/reaction systems can be easily applied to outstanding problems in computational biology. First, we examine a three-dimensional model for calcium wave propagation in a Xenopus Laevis frog egg and verify that a proposed model for the distribution of calcium release sites agrees with experimental results as a function of both space and time. Next, we create a model of the neuron's terminus based on experimental observations and show that the sodium-calcium exchanger is not the route of sodium's modulation of neurotransmitter release. These state-of-the-art simulations were performed on massively parallel platforms and required almost no modification of existing Sandia codes
Impact of genetic variation on human CaMKK2 regulation by Ca2+ -calmodulin and multisite phosphorylation
The Ca2+-calmodulin dependent protein kinase kinase-2 (CaMKK2) is a key regulator of neuronal function and whole-body energy metabolism. Elevated CaMKK2 activity is strongly associated with prostate and hepatic cancers, whereas reduced CaMKK2 activity has been linked to schizophrenia and bipolar disease in humans. Here we report the functional effects of nine rare-variant point mutations that were detected in large-scale human genetic studies and cancer tissues, all of which occur close to two regulatory phosphorylation sites and the catalytic site on human CaMKK2. Four mutations (G87R, R139W, R142W and E268K) cause a marked decrease in Ca2+-independent autonomous activity, however S137L and P138S mutants displayed increased autonomous and Ca2+-CaM stimulated activities. Furthermore, the G87R mutant is defective in Thr85-autophosphorylation dependent autonomous activity, whereas the A329T mutation rendered CaMKK2 virtually insensitive to Ca2+-CaM stimulation. The G87R and R139W mutants behave as dominant-negative inhibitors of CaMKK2 signaling in cells as they block phosphorylation of the downstream substrate AMP-activated protein kinase (AMPK) in response to ionomycin. Our study provides insight into functionally disruptive, rare-variant mutations in human CaMKK2, which have the potential to influence risk and burden of disease associated with aberrant CaMKK2 activity in human populations carrying these variants
Identification of Unique MicroRNA Signature Associated with Lupus Nephritis
MicroRNAs (miRNA) have emerged as an important new class of modulators of gene expression. In this study we investigated miRNA that are differentially expressed in lupus nephritis. Microarray technology was used to investigate differentially expressed miRNA in peripheral blood mononuclear cells (PBMCs) and Epstein-Barr Virus (EBV)-transformed cell lines obtained from lupus nephritis affected patients and unaffected controls. TaqMan-based stem-loop real-time polymerase chain reaction was used for validation. Microarray analysis of miRNA expressed in both African American (AA) and European American (EA) derived lupus nephritis samples revealed 29 and 50 differentially expressed miRNA, respectively, of 850 tested. There were 18 miRNA that were differentially expressed in both racial groups. When samples from both racial groups and different specimen types were considered, there were 5 primary miRNA that were differentially expressed. We have identified 5 miRNA; hsa-miR-371-5P, hsa-miR-423-5P, hsa-miR-638, hsa-miR-1224-3P and hsa-miR-663 that were differentially expressed in lupus nephritis across different racial groups and all specimen types tested. Hsa-miR-371-5P, hsa-miR-1224-3P and hsa-miR-423-5P, are reported here for the first time to be associated with lupus nephritis. Our work establishes EBV-transformed B cell lines as a useful model for the discovery of miRNA as biomarkers for SLE. Based on these findings, we postulate that these differentially expressed miRNA may be potential novel biomarkers for SLE as well as help elucidate pathogenic mechanisms of lupus nephritis. The investigation of miRNA profiles in SLE may lead to the discovery and development of novel methods to diagnosis, treat and prevent SLE
CaMKK2 as an emerging treatment target for bipolar disorder
Current pharmacological treatments for bipolar disorder are inadequate and based on serendipitously discovered drugs often with limited efficacy, burdensome side-effects, and unclear mechanisms of action. Advances in drug development for the treatment of bipolar disorder remain incremental and have come largely from repurposing drugs used for other psychiatric conditions, a strategy that has failed to find truly revolutionary therapies, as it does not target the mood instability that characterises the condition. The lack of therapeutic innovation in the bipolar disorder field is largely due to a poor understanding of the underlying disease mechanisms and the consequent absence of validated drug targets. A compelling new treatment target is the Ca2+-calmodulin dependent protein kinase kinase-2 (CaMKK2) enzyme. CaMKK2 is highly enriched in brain neurons and regulates energy metabolism and neuronal processes that underpin higher order functions such as long-term memory, mood, and other affective functions. Loss-of-function polymorphisms and a rare missense mutation in human CAMKK2 are associated with bipolar disorder, and genetic deletion of Camkk2 in mice causes bipolar-like behaviours similar to those in patients. Furthermore, these behaviours are ameliorated by lithium, which increases CaMKK2 activity. In this review, we discuss multiple convergent lines of evidence that support targeting of CaMKK2 as a new treatment strategy for bipolar disorder
Calcium/calmodulin-dependent protein kinase kinase 2 regulates hepatic fuel metabolism
Objective
The liver is the primary internal metabolic organ that coordinates whole body energy homeostasis in response to feeding and fasting. Genetic ablation or pharmacological inhibition of calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) has been shown to significantly improve hepatic health and peripheral insulin sensitivity upon overnutrition with high fat diet. However, the precise molecular underpinnings that explain this metabolic protection have remained largely undefined.
Methods
To characterize the role of CaMKK2 in hepatic metabolism, we developed and challenged liver-specific CaMKK2 knockout (CaMKK2LKO) mice with high fat diet and performed glucose and insulin tolerance tests to evaluate peripheral insulin sensitivity. We used a combination of RNA-Sequencing, glucose and fatty acid istotopic tracer studies, a newly developed Seahorse assay for measuring the oxidative capacity of purified peroxisomes, and a degenerate peptide libarary to identify putative CaMKK2 substrates that mechanistically explain the protective effects of hepatic CaMKK2 ablation.
Results
Consistent with previous findings, we show that hepatic CaMKK2 ablation significantly improves indices of peripheral insulin sensitivity. Mechanistically, we found that CaMKK2 phosphorylates and regulates GAPDH to promote glucose metabolism and PEX3 to blunt peroxisomal fatty acid catabolism in the liver.
Conclusion
CaMKK2 is a central metabolic fuel sensor in the liver that significantly contributes to whole body systems metabolism
Upsilon (1S+2S+3S) production in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and cold-nuclear matter effects
The three Upsilon states, Upsilon(1S+2S+3S), are measured in d+Au and p+p
collisions at sqrt(s_NN)=200 GeV and rapidities 1.2<|y|<2.2 by the PHENIX
experiment at the Relativistic Heavy-Ion Collider. Cross sections for the
inclusive Upsilon(1S+2S+3S) production are obtained. The inclusive yields per
binary collision for d+Au collisions relative to those in p+p collisions
(R_dAu) are found to be 0.62 +/- 0.26 (stat) +/- 0.13 (syst) in the gold-going
direction and 0.91 +/- 0.33 (stat) +/- 0.16 (syst) in the deuteron-going
direction. The measured results are compared to a nuclear-shadowing model,
EPS09 [JHEP 04, 065 (2009)], combined with a final-state breakup cross section,
sigma_br, and compared to lower energy p+A results. We also compare the results
to the PHENIX J/psi results [Phys. Rev. Lett. 107, 142301 (2011)]. The rapidity
dependence of the observed Upsilon suppression is consistent with lower energy
p+A measurements.Comment: 495 authors, 11 pages, 9 figures, 5 tables. Submitted to Phys. Rev.
C. Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Double Spin Asymmetry of Electrons from Heavy Flavor Decays in p+p Collisions at sqrt(s)=200 GeV
We report on the first measurement of double-spin asymmetry, A_LL, of
electrons from the decays of hadrons containing heavy flavor in longitudinally
polarized p+p collisions at sqrt(s)=200 GeV for p_T= 0.5 to 3.0 GeV/c. The
asymmetry was measured at mid-rapidity (|eta|<0.35) with the PHENIX detector at
the Relativistic Heavy Ion Collider. The measured asymmetries are consistent
with zero within the statistical errors. We obtained a constraint for the
polarized gluon distribution in the proton of |Delta g/g(log{_10}x=
-1.6^+0.5_-0.4, {mu}=m_T^c)|^2 < 0.033 (1 sigma), based on a leading-order
perturbative-quantum-chromodynamics model, using the measured asymmetry.Comment: 385 authors, 17 pages, 15 figures, 5 tables. Submitted to Phys. Rev.
D. Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
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