A single chip 2 Gbit/s clock recovery subsystem for digital communications

NASA Astrophysics Data System (ADS)

Hickling, Ronald M.

A self-contained clock recovery/data resynchronizer phase locked loop (PLL) for use in microwave and fiber optic digital communications has been fabricated using GaAs integrated circuit technology. The IC contains the analog and digital components for the PLL: an edge-triggered phase detector based on a 1.2 GHz phase/frequency comparator, an op amp for creating the loop filter, and a VCO based on a differential source-coupled pair amplifier.

Demodulation Radio Frequency Interference Effects in Operational Amplifier Circuits

NASA Astrophysics Data System (ADS)

Sutu, Yue-Hong

A series of investigations have been carried out to determine RFI effects in analog circuits using monolithic integrated operational amplifiers (op amps) as active devices. The specific RFI effect investigated is how amplitude-modulated (AM) RF signals are demodulated in op amp circuits to produce undesired low frequency responses at AM-modulation frequency. The undesired demodulation responses were shown to be characterized by a second-order nonlinear transfer function. Four representative op amp types investigated were the 741 bipolar op amp, the LM10 bipolar op amp, the LF355 JFET-Bipolar op amp, and the CA081 MOS-Bipolar op amp. Two op amp circuits were investigated. The first circuit was a noninverting unity voltage gain buffer circuit. The second circuit was an inverting op amp configuration. In the second circuit, the investigation includes the effects of an RFI suppression capacitor in the feedback path. Approximately 30 units of each op amp type were tested to determine the statistical variations of RFI demodulation effects in the two op amp circuits. The Nonlinear Circuit Analysis Program, NCAP, was used to simulate the demodulation RFI response. In the simulation, the op amp was replaced with its incremental macromodel. Values of macromodel parameters were obtained from previous investigations and manufacturer's data sheets. Some key results of this work are: (1) The RFI demodulation effects are 10 to 20 dB lower in CA081 and LF355 FET-bipolar op amp than in 741 and LM10 bipolar op amp except above 40 MHz where the LM10 RFI response begins to approach that of CA081. (2) The experimental mean values for 30 741 op amps show that RFI demodulation responses in the inverting amplifier with a 27 pF feedback capacitor were suppressed from 10 to 35 dB over the RF frequency range 0.1 to 150 MHz except at 0.15 MHz where only 3.5 dB suppression was observed. (3) The NCAP program can predict RFI demodulation responses in 741 and LF355 unity gain buffer circuits

Effects of adrenomedullin on cyclic AMP formation and on relaxation in iris sphincter smooth muscle.

PubMed

Yousufzai, S Y; Ali, N; Abdel-Latif, A A

1999-12-01

To determine whether iris sphincter and other tissues of the iris-ciliary body secrete adrenomedullin (ADM), a novel hypotensive peptide that is classified into the calcitonin gene-related peptide (CGRP) family and to determine the binding sites for ADM and compare the effects of ADM and CGRP in the absence and presence of their receptor antagonists on cAMP formation and relaxation in the iris sphincter. Sphincter muscle was incubated in Krebs-Ringer bicarbonate buffer in the absence and presence of ADM for 10 minutes. Accumulation of cAMP in the tissue extract was determined by radioimmunoassay (RIA). The binding of [125I]ADM to iris sphincter membranes was carried out by rapid filtration. Distribution of ADM in the ocular tissues was determined by RIA. Changes in muscle tension were recorded isometrically. Immunoreactive ADM was present in all tissues of the cat iris-ciliary body. In the isolated cat iris sphincter, ADM increased cAMP accumulation in a time- (t1/2 = 2.2 minutes) and concentration- (EC50 = 13 nM) dependent manner, and this effect was sixfold more efficacious than CGRP. ADM, CGRP, vasoactive intestinal peptide, prostaglandin E2, isoproterenol, and forskolin increased cAMP formation in cat sphincter by 12.5-, 2-, 2.2-, 1-, 2.6-, and 2.4-fold, respectively. The rank of the effects of ADM on cAMP formation in iris sphincter isolated from different animal species was in the following order: cat > dog > bovine > human > rabbit. In the cat iris sphincter, the CGRP antagonist, CGRP(8 to 37), was more effective than the ADM antagonist, ADM (26 to 52), in inhibiting both ADM- and CGRP-induced cAMP formation. ADM and CGRP inhibited carbachol-induced contraction in a concentration-dependent manner with IC50 values of 10 and 90 nM, respectively. Both ADM and CGRP displaced the binding of [125I]ADM to sphincter membranes effectively, with IC50 values of 0.81 and 1.15 nM, respectively. In iris sphincter isolated from cat and other mammalian species including

Schwann Cells Metabolize Extracellular 2′,3′-cAMP to 2′-AMP

PubMed Central

Verrier, Jonathan D.; Kochanek, Patrick M.

2015-01-01

The 3′,5′-cAMP–adenosine pathway (3′,5′-cAMP→5′-AMP→adenosine) and the 2′,3′-cAMP–adenosine pathway (2′,3′-cAMP→2′-AMP/3′-AMP→adenosine) are active in the brain. Oligodendrocytes participate in the brain 2′,3′-cAMP–adenosine pathway via their robust expression of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase; converts 2′,3′-cAMP to 2′-AMP). Because Schwann cells also express CNPase, it is conceivable that the 2′,3′-cAMP–adenosine pathway exists in the peripheral nervous system. To test this and to compare the 2′,3′-cAMP–adenosine pathway to the 3′,5′-cAMP–adenosine pathway in Schwann cells, we examined the metabolism of 2′,3′-cAMP, 2′-AMP, 3′-AMP, 3′,5′-cAMP, and 5′-AMP in primary rat Schwann cells in culture. Addition of 2′,3′-cAMP (3, 10, and 30 µM) to Schwann cells increased levels of 2′-AMP in the medium from 0.006 ± 0.002 to 21 ± 2, 70 ± 3, and 187 ± 10 nM/µg protein, respectively; in contrast, Schwann cells had little ability to convert 2′,3′-cAMP to 3′-AMP or 3′,5′-cAMP to either 3′-AMP or 5′-AMP. Although Schwann cells slightly converted 2′,3′-cAMP and 2′-AMP to adenosine, they did so at very modest rates (e.g., 5- and 3-fold, respectively, more slowly compared with our previously reported studies in oligodendrocytes). Using transected myelinated rat sciatic nerves in culture medium, we observed a time-related increase in endogenous intracellular 2′,3′-cAMP and extracellular 2′-AMP. These findings indicate that Schwann cells do not have a robust 3′,5′-cAMP–adenosine pathway but do have a 2′,3′-cAMP–adenosine pathway; however, because the pathway mostly involves 2′-AMP formation rather than 3′-AMP, and because the conversion of 2′-AMP to adenosine is slow, metabolism of 2′,3′-cAMP mostly results in the accumulation of 2′-AMP. Accumulation of 2′-AMP in peripheral nerves postinjury could have

Discovery of a cAMP Deaminase That Quenches Cyclic AMP-Dependent Regulation

PubMed Central

Goble, Alissa M.; Feng, Youjun; Raushel, Frank M.; Cronan, John E.

2013-01-01

An enzyme of unknown function within the amidohydrolase superfamily was discovered to catalyze the hydrolysis of the universal second messenger, cyclic-3’, 5’-adenosine monophosphate (cAMP). The enzyme, which we have named CadD, is encoded by the human pathogenic bacterium Leptospira interrogans. Although CadD is annotated as an adenosine deaminase, the protein specifically deaminates cAMP to cyclic-3’, 5’-inosine monophosphate (cIMP) with a kcat/Km of 2.7 ± 0.4 × 105 M−1 s−1 and has no activity on adenosine, adenine, or 5’-adenosine monophosphate (AMP). This is the first identification of a deaminase specific for cAMP. Expression of CadD in Escherichia coli mimics the loss of adenylate cyclase in that it blocks growth on carbon sources that require the cAMP-CRP transcriptional activator complex for expression of the cognate genes. The cIMP reaction product cannot replace cAMP as the ligand for CRP binding to DNA in vitro and cIMP is a very poor competitor of cAMP activation of CRP for DNA binding. Transcriptional analyses indicate that CadD expression represses expression of several cAMP-CRP dependent genes. CadD adds a new activity to the cAMP metabolic network and may be a useful tool in intracellular study of cAMP-dependent processes. PMID:24074367

AMP deaminase 3 deficiency enhanced 5'-AMP induction of hypometabolism.

PubMed

Daniels, Isadora Susan; O Brien, William G; Nath, Vinay; Zhao, Zhaoyang; Lee, Cheng Chi

2013-01-01

A hypometabolic state can be induced in mice by 5'-AMP administration. Previously we proposed that an underlying mechanism for this hypometabolism is linked to reduced erythrocyte oxygen transport function due to 5'-AMP uptake altering the cellular adenylate equilibrium. To test this hypothesis, we generated mice deficient in adenosine monophosphate deaminase 3 (AMPD3), the key catabolic enzyme for 5'-AMP in erythrocytes. Mice deficient in AMPD3 maintained AMPD activities in all tissues except erythrocytes. Developmentally and morphologically, the Ampd3(-/-) mice were indistinguishable from their wild type siblings. The levels of ATP, ADP but not 5'-AMP in erythrocytes of Ampd3(-/-) mice were significantly elevated. Fasting blood glucose levels of the Ampd3(-/-) mice were comparable to wild type siblings. In comparison to wild type mice, the Ampd3(-/-) mice displayed a deeper hypometabolism with a significantly delayed average arousal time in response to 5'-AMP administration. Together, these findings demonstrate a central role of AMPD3 in the regulation of 5'-AMP mediated hypometabolism and further implicate erythrocytes in this behavioral response.

2′,3′-cAMP, 3′-AMP, and 2′-AMP inhibit human aortic and coronary vascular smooth muscle cell proliferation via A2B receptors

PubMed Central

Ren, Jin; Gillespie, Delbert G.

2011-01-01

Rat vascular smooth muscle cells (VSMCs) from renal microvessels metabolize 2′,3′-cAMP to 2′-AMP and 3′-AMP, and these AMPs are converted to adenosine that inhibits microvascular VSMC proliferation via A2B receptors. The goal of this study was to test whether this mechanism also exists in VSMCs from conduit arteries and whether it is similarly expressed in human vs. rat VSMCs. Incubation of rat and human aortic VSMCs with 2′,3′-cAMP concentration-dependently increased levels of 2′-AMP and 3′-AMP in the medium, with a similar absolute increase in 2′-AMP vs. 3′-AMP. In contrast, in human coronary VSMCs, 2′,3′-cAMP increased 2′-AMP levels yet had little effect on 3′-AMP levels. In all cell types, 2′,3′-cAMP increased levels of adenosine, but not 5′-AMP, and 2′,3′-AMP inhibited cell proliferation. Antagonism of A2B receptors (MRS-1754), but not A1 (1,3-dipropyl-8-cyclopentylxanthine), A2A (SCH-58261), or A3 (VUF-5574) receptors, attenuated the antiproliferative effects of 2′,3′-cAMP. In all cell types, 2′-AMP, 3′-AMP, and 5′-AMP increased adenosine levels, and inhibition of ecto-5′-nucleotidase blocked this effect of 5′-AMP but not that of 2′-AMP nor 3′-AMP. Also, 2′-AMP, 3′-AMP, and 5′-AMP, like 2′,3′-cAMP, exerted antiproliferative effects that were abolished by antagonism of A2B receptors with MRS-1754. In conclusion, VSMCs from conduit arteries metabolize 2′,3′-cAMP to AMPs, which are metabolized to adenosine. In rat and human aortic VSMCs, both 2′-AMP and 3′-AMP are involved in this process, whereas, in human coronary VSMCs, 2′,3′-cAMP is mainly converted to 2′-AMP. Because adenosine inhibits VSMC proliferation via A2B receptors, local vascular production of 2′,3′-cAMP may protect conduit arteries from atherosclerosis. PMID:21622827

Metformin and phenformin activate AMP-activated protein kinase in the heart by increasing cytosolic AMP concentration.

PubMed

Zhang, Li; He, Huamei; Balschi, James A

2007-07-01

AMP-activated protein kinase (AMPK) acts as a cellular energy sensor: it responds to an increase in AMP concentration ([AMP]) or the AMP-to-ATP ratio (AMP/ATP). Metformin and phenformin, which are biguanides, have been reported to increase AMPK activity without increasing AMP/ATP. This study tests the hypothesis that these biguanides increase AMPK activity in the heart by increasing cytosolic [AMP]. Groups of isolated rat hearts (n = 5-7 each) were perfused with Krebs-Henseleit buffer with or without 0.2 mM phenformin or 10 mM metformin, and (31)P-NMR-measured phosphocreatine, ATP, and intracellular pH were used to calculate cytosolic [AMP]. At various times, hearts were freeze-clamped and assayed for AMPK activity, phosphorylation of Thr(172) on AMPK-alpha, and phosphorylation of Ser(79) on acetyl-CoA carboxylase, an AMPK target. In hearts treated with phenformin for 18 min and then perfused for 20 min with Krebs-Henseleit buffer, [AMP] began to increase at 26 min and AMPK activity was elevated at 36 min. In hearts treated with metformin, [AMP] was increased at 50 min and AMPK activity, phosphorylated AMPK, and phosphorylated acetyl-CoA carboxylase were elevated at 61 min. In metformin-treated hearts, HPLC-measured total AMP content and total AMP/ATP did not increase. In summary, phenformin and metformin increase AMPK activity and phosphorylation in the isolated heart. The increase in AMPK activity was always preceded by and correlated with increased cytosolic [AMP]. Total AMP content and total AMP/ATP did not change. Cytosolic [AMP] reported metabolically active AMP, which triggered increased AMPK activity, but measures of total AMP did not.

AMP Deaminase 3 Deficiency Enhanced 5′-AMP Induction of Hypometabolism

PubMed Central

Daniels, Isadora Susan; O′Brien, William G.; Nath, Vinay; Zhao, Zhaoyang; Lee, Cheng Chi

2013-01-01

A hypometabolic state can be induced in mice by 5′-AMP administration. Previously we proposed that an underlying mechanism for this hypometabolism is linked to reduced erythrocyte oxygen transport function due to 5′-AMP uptake altering the cellular adenylate equilibrium. To test this hypothesis, we generated mice deficient in adenosine monophosphate deaminase 3 (AMPD3), the key catabolic enzyme for 5′-AMP in erythrocytes. Mice deficient in AMPD3 maintained AMPD activities in all tissues except erythrocytes. Developmentally and morphologically, the Ampd3−/− mice were indistinguishable from their wild type siblings. The levels of ATP, ADP but not 5′-AMP in erythrocytes of Ampd3−/− mice were significantly elevated. Fasting blood glucose levels of the Ampd3−/− mice were comparable to wild type siblings. In comparison to wild type mice, the Ampd3−/− mice displayed a deeper hypometabolism with a significantly delayed average arousal time in response to 5′-AMP administration. Together, these findings demonstrate a central role of AMPD3 in the regulation of 5′-AMP mediated hypometabolism and further implicate erythrocytes in this behavioral response. PMID:24066180

2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine inhibit TNF-α and CXCL10 production from activated primary murine microglia via A2A receptors.

PubMed

Newell, Elizabeth A; Exo, Jennifer L; Verrier, Jonathan D; Jackson, Travis C; Gillespie, Delbert G; Janesko-Feldman, Keri; Kochanek, Patrick M; Jackson, Edwin K

2015-01-12

Some cells, tissues and organs release 2',3'-cAMP (a positional isomer of 3',5'-cAMP) and convert extracellular 2',3'-cAMP to 2'-AMP plus 3'-AMP and convert these AMPs to adenosine (called the extracellular 2',3'-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2',3'-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2',3'-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 μM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N(6)-cyclopentyladenosine (CCPA) (10 μM; selective A1 agonist), 5'-N-ethylcarboxamide adenosine (NECA) (10 μM; agonist for all adenosine receptor subtypes) and CGS21680 (10 μM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. (1) 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; (2) DPSPX nearly eliminated the inhibitory effects of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; (3) CCPA did not affect LPS-induced TNF-α and CXCL10; (4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. 2',3'-cAMP and its metabolites (3'-AMP, 2'-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

cAMP and Mitochondria

PubMed Central

Valsecchi, Federica; Ramos-Espiritu, Lavoisier S.; Buck, Jochen; Levin, Lonny R.

2013-01-01

Phosphorylation of mitochondrial proteins has emerged as a major regulatory mechanism for metabolic adaptation. cAMP signaling and PKA phosphorylation of mitochondrial proteins have just started to be investigated, and the presence of cAMP-generating enzymes and PKA inside mitochondria is still controversial. Here, we discuss the role of cAMP in regulating mitochondrial bioenergetics through protein phosphorylation and the evidence for soluble adenylyl cyclase as the source of cAMP inside mitochondria. PMID:23636265

Cyclic AMP- and (Rp)-cAMPS-induced Conformational Changes in a Complex of the Catalytic and Regulatory (RIα) Subunits of Cyclic AMP-dependent Protein Kinase*

PubMed Central

Anand, Ganesh S.; Krishnamurthy, Srinath; Bishnoi, Tanushree; Kornev, Alexandr; Taylor, Susan S.; Johnson, David A.

2010-01-01

We took a discovery approach to explore the actions of cAMP and two of its analogs, one a cAMP mimic ((Sp)-adenosine cyclic 3′:5′-monophosphorothioate ((Sp)-cAMPS)) and the other a diastereoisomeric antagonist ((Rp)-cAMPS), on a model system of the type Iα cyclic AMP-dependent protein kinase holoenzyme, RIα(91–244)·C-subunit, by using fluorescence spectroscopy and amide H/2H exchange mass spectrometry. Specifically, for the fluorescence experiments, fluorescein maleimide was conjugated to three cysteine single residue substitution mutants, R92C, T104C, and R239C, of RIα(91–244), and the effects of cAMP, (Sp)-cAMPS, and (Rp)-cAMPS on the kinetics of R-C binding and the time-resolved anisotropy of the reporter group at each conjugation site were measured. For the amide exchange experiments, ESI-TOF mass spectrometry with pepsin proteolytic fragmentation was used to assess the effects of (Rp)-cAMPS on amide exchange of the RIα(91–244)·C-subunit complex. We found that cAMP and its mimic perturbed at least parts of the C-subunit interaction Sites 2 and 3 but probably not Site 1 via reduced interactions of the linker region and αC of RIα(91–244). Surprisingly, (Rp)-cAMPS not only increased the affinity of RIα(91–244) toward the C-subunit by 5-fold but also produced long range effects that propagated through both the C- and R-subunits to produce limited unfolding and/or enhanced conformational flexibility. This combination of effects is consistent with (Rp)-cAMPS acting by enhancing the internal entropy of the R·C complex. Finally, the (Rp)-cAMPS-induced increase in affinity of RIα(91–244) toward the C-subunit indicates that (Rp)-cAMPS is better described as an inverse agonist because it decreases the fractional dissociation of the cyclic AMP-dependent protein kinase holoenzyme and in turn its basal activity. PMID:20167947

Advanced Multi-Physics (AMP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philip, Bobby

2012-06-01

The Advanced Multi-Physics (AMP) code, in its present form, will allow a user to build a multi-physics application code for existing mechanics and diffusion operators and extend them with user-defined material models and new physics operators. There are examples that demonstrate mechanics, thermo-mechanics, coupled diffusion, and mechanical contact. The AMP code is designed to leverage a variety of mathematical solvers (PETSc, Trilinos, SUNDIALS, and AMP solvers) and mesh databases (LibMesh and AMP) in a consistent interchangeable approach.

Mod 1 ICS TI Report: ICS Conversion of a 140% HPGe Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bounds, John Alan

This report evaluates the Mod 1 ICS, an electrically cooled 140% HPGe detector. It is a custom version of the ORTEC Integrated Cooling System (ICS) modified to make it more practical for us to use in the field. Performance and operating characteristics of the Mod 1 ICS are documented, noting both pros and cons. The Mod 1 ICS is deemed a success. Recommendations for a Mod 2 ICS, a true field prototype, are provided.

Rp-cAMPS Prodrugs Reveal the cAMP Dependence of First-Phase Glucose-Stimulated Insulin Secretion

PubMed Central

Schwede, Frank; Chepurny, Oleg G.; Kaufholz, Melanie; Bertinetti, Daniela; Leech, Colin A.; Cabrera, Over; Zhu, Yingmin; Mei, Fang; Cheng, Xiaodong; Manning Fox, Jocelyn E.; MacDonald, Patrick E.; Genieser, Hans-G.; Herberg, Friedrich W.

2015-01-01

cAMP-elevating agents such as the incretin hormone glucagon-like peptide-1 potentiate glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. However, a debate has existed since the 1970s concerning whether or not cAMP signaling is essential for glucose alone to stimulate insulin secretion. Here, we report that the first-phase kinetic component of GSIS is cAMP-dependent, as revealed through the use of a novel highly membrane permeable para-acetoxybenzyl (pAB) ester prodrug that is a bioactivatable derivative of the cAMP antagonist adenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer (Rp-cAMPS). In dynamic perifusion assays of human or rat islets, a step-wise increase of glucose concentration leads to biphasic insulin secretion, and under these conditions, 8-bromoadenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer, 4-acetoxybenzyl ester (Rp-8-Br-cAMPS-pAB) inhibits first-phase GSIS by up to 80%. Surprisingly, second-phase GSIS is inhibited to a much smaller extent (≤20%). Using luciferase, fluorescence resonance energy transfer, and bioluminescence resonance energy transfer assays performed in living cells, we validate that Rp-8-Br-cAMPS-pAB does in fact block cAMP-dependent protein kinase activation. Novel effects of Rp-8-Br-cAMPS-pAB to block the activation of cAMP-regulated guanine nucleotide exchange factors (Epac1, Epac2) are also validated using genetically encoded Epac biosensors, and are independently confirmed in an in vitro Rap1 activation assay using Rp-cAMPS and Rp-8-Br-cAMPS. Thus, in addition to revealing the cAMP dependence of first-phase GSIS from human and rat islets, these findings establish a pAB-based chemistry for the synthesis of highly membrane permeable prodrug derivatives of Rp-cAMPS that act with micromolar or even nanomolar potency to inhibit cAMP signaling in living cells. PMID:26061564

Parallel Allostery by cAMP and PDE Coordinates Activation and Termination Phases in cAMP Signaling.

PubMed

Krishnamurthy, Srinath; Tulsian, Nikhil Kumar; Chandramohan, Arun; Anand, Ganesh S

2015-09-15

The second messenger molecule cAMP regulates the activation phase of the cAMP signaling pathway through high-affinity interactions with the cytosolic cAMP receptor, the protein kinase A regulatory subunit (PKAR). Phosphodiesterases (PDEs) are enzymes responsible for catalyzing hydrolysis of cAMP to 5' AMP. It was recently shown that PDEs interact with PKAR to initiate the termination phase of the cAMP signaling pathway. While the steps in the activation phase are well understood, steps in the termination pathway are unknown. Specifically, the binding and allosteric networks that regulate the dynamic interplay between PKAR, PDE, and cAMP are unclear. In this study, PKAR and PDE from Dictyostelium discoideum (RD and RegA, respectively) were used as a model system to monitor complex formation in the presence and absence of cAMP. Amide hydrogen/deuterium exchange mass spectrometry was used to monitor slow conformational transitions in RD, using disordered regions as conformational probes. Our results reveal that RD regulates its interactions with cAMP and RegA at distinct loci by undergoing slow conformational transitions between two metastable states. In the presence of cAMP, RD and RegA form a stable ternary complex, while in the absence of cAMP they maintain transient interactions. RegA and cAMP each bind at orthogonal sites on RD with resultant contrasting effects on its dynamics through parallel allosteric relays at multiple important loci. RD thus serves as an integrative node in cAMP termination by coordinating multiple allosteric relays and governing the output signal response. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Macrophage deficiency in osteopetrotic (op/op) mice inhibits activation of satellite cells and prevents hypertrophy in single soleus fibers.

PubMed

Ohira, T; Wang, X D; Ito, T; Kawano, F; Goto, K; Izawa, T; Ohno, H; Kizaki, T; Ohira, Y

2015-05-15

Effects of macrophage on the responses of soleus fiber size to hind limb unloading and reloading were studied in osteopetrotic homozygous (op/op) mice with inactivated mutation of macrophage colony-stimulating factor (M-CSF) gene and in wild-type (+/+) and heterozygous (+/op) mice. The basal levels of mitotically active and quiescent satellite cell (-46 and -39% vs. +/+, and -40 and -30% vs. +/op) and myonuclear number (-29% vs. +/+ and -28% vs. +/op) in fibers of op/op mice were significantly less than controls. Fiber length and sarcomere number in op/op were also less than +/+ (-22%) and +/op (-21%) mice. Similar trend was noted in fiber cross-sectional area (CSA, -15% vs. +/+, P = 0.06, and -14% vs. +/op, P = 0.07). The sizes of myonuclear domain, cytoplasmic volume per myonucleus, were identical in all types of mice. The CSA, length, and the whole number of sarcomeres, myonuclei, and mitotically active and quiescent satellite cells, as well as myonuclear domain, in single muscle fibers were decreased after 10 days of unloading in all types of mice, although all of these parameters in +/+ and +/op mice were increased toward the control values after 10 days of reloading. However, none of these levels in op/op mice were recovered. Data suggest that M-CSF and/or macrophages are important to activate satellite cells, which cause increase of myonuclear number during fiber hypertrophy. However, it is unclear why their responses to general growth and reloading after unloading are different. Copyright © 2015 the American Physiological Society.

Surrealism Meets OP

ERIC Educational Resources Information Center

Bowden, Jennifer

2006-01-01

Kids always seem to like Surrealism and Op Art. This is a fun project that is popular with students. With Op Art patience and attention to details are required while Surrealistic collage needs strong composition skills for the image placement. Often, many images must be left out to create a clean design. Artistic decisions must be based on the art…

Cn-AMP2 from green coconut water is an anionic anticancer peptide.

PubMed

Prabhu, Saurabh; Dennison, Sarah R; Mura, Manuela; Lea, Robert W; Snape, Timothy J; Harris, Frederick

2014-12-01

Globally, death due to cancers is likely to rise to over 20 million by 2030, which has created an urgent need for novel approaches to anticancer therapies such as the development of host defence peptides. Cn-AMP2 (TESYFVFSVGM), an anionic host defence peptide from green coconut water of the plant Cocos nucifera, showed anti-proliferative activity against the 1321N1 and U87MG human glioma cell lines with IC50 values of 1.25 and 1.85 mM, respectively. The membrane interactive form of the peptide was found to be an extended conformation, which primarily included β-type structures (levels > 45%) and random coil architecture (levels > 45%). On the basis of these and other data, it is suggested that the short anionic N-terminal sequence (TES) of Cn-AMP2 interacts with positively charged moieties in the cancer cell membrane. Concomitantly, the long hydrophobic C-terminal sequence (YFVFSVGM) of the peptide penetrates the membrane core region, thereby driving the translocation of Cn-AMP2 across the cancer cell membrane to attack intracellular targets and induce anti-proliferative mechanisms. This work is the first to demonstrate that anionic host defence peptides have activity against human glioblastoma, which potentially provides an untapped source of lead compounds for development as novel agents in the treatment of these and other cancers. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

Nonlinear system analysis in bipolar integrated circuits

NASA Astrophysics Data System (ADS)

Fang, T. F.; Whalen, J. J.

1980-01-01

Since analog bipolar integrated circuits (IC's) have become important components in modern communication systems, the study of the Radio Frequency Interference (RFI) effects in bipolar IC amplifiers is an important subject for electromagnetic compatibility (EMC) engineering. The investigation has focused on using the nonlinear circuit analysis program (NCAP) to predict RF demodulation effects in broadband bipolar IC amplifiers. The audio frequency (AF) voltage at the IC amplifier output terminal caused by an amplitude modulated (AM) RF signal at the IC amplifier input terminal was calculated and compared to measured values. Two broadband IC amplifiers were investigated: (1) a cascode circuit using a CA3026 dual differential pair; (2) a unity gain voltage follower circuit using a micro A741 operational amplifier (op amp). Before using NCAP for RFI analysis, the model parameters for each bipolar junction transistor (BJT) in the integrated circuit were determined. Probe measurement techniques, manufacturer's data, and other researcher's data were used to obtain the required NCAP BJT model parameter values. An important contribution included in this effort is a complete set of NCAP BJT model parameters for most of the transistor types used in linear IC's.

THE OPS-1 MANUAL,

DTIC Science & Technology

wide range of human activity . Activities relating to management are the concern of a trial system at Project MAC called OPS-1. The OPS-1 system and the experiment that launched it are described in the manual. (Author)

Statistics for demodulation RFI in inverting operational amplifier circuits

NASA Astrophysics Data System (ADS)

Sutu, Y.-H.; Whalen, J. J.

An investigation was conducted with the objective to determine statistical variations for RFI demodulation responses in operational amplifier (op amp) circuits. Attention is given to the experimental procedures employed, a three-stage op amp LED experiment, NCAP (Nonlinear Circuit Analysis Program) simulations of demodulation RFI in 741 op amps, and a comparison of RFI in four op amp types. Three major recommendations for future investigations are presented on the basis of the obtained results. One is concerned with the conduction of additional measurements of demodulation RFI in inverting amplifiers, while another suggests the employment of an automatic measurement system. It is also proposed to conduct additional NCAP simulations in which parasitic effects are accounted for more thoroughly.

Candidate OP Phyla: Importance, Ecology and Cultivation Prospects.

PubMed

Rohini Kumar, M; Saravanan, V S

2010-10-01

OP phyla were created in the domain bacteria, based on the group of 16S rRNA gene sequences recovered from the Obsidian Pool. However, due to the lack of cultured representative it is referred to as candidate phyla. Wider ecological occurrence was predicted for the OP phyla, especially OP3, OP10 and OP11. Recently, members of phylum OP5 and OP10 were cultured, providing clues to their cultivation prospects. At last the bioprospecting potentials of the OP members are discussed herein.

AMPED Program Overview

ScienceCinema

Gur, Ilan

2018-01-16

An overview presentation about ARPA-E's AMPED program. AMPED projects seek to develop advanced sensing, control, and power management technologies that redefine the way we think about battery management. Energy storage can significantly improve U.S. energy independence, efficiency, and security by enabling a new generation of electric vehicles. While rapid progress is being made in new battery materials and storage technologies, few innovations have emerged in the management of advanced battery systems. AMPED aims to unlock enormous untapped potential in the performance, safety, and lifetime of today's commercial battery systems exclusively through system-level innovations, and is thus distinct from existing efforts to enhance underlying battery materials and architectures.

2’,3’-cAMP, 3’-AMP, 2’-AMP and Adenosine Inhibit TNF-α and CXCL10 Production From Activated Primary Murine Microglia via A2A Receptors

PubMed Central

Newell, Elizabeth A.; Exo, Jennifer L.; Verrier, Jonathan D.; Jackson, Travis C.; Gillespie, Delbert G.; Janesko-Feldman, Keri; Kochanek, Patrick M.

2014-01-01

Background Some cells, tissues and organs release 2’,3’-cAMP (a positional isomer of 3’,5’-cAMP) and convert extracellular 2’,3’-cAMP to 2’-AMP plus 3’-AMP and convert these AMPs to adenosine (called the extracellular 2’,3’-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2’,3’-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2’,3’-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Methods Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 µM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N6-cyclopentyladenosine (CCPA) (10 µM; selective A1 agonist), 5’-N-ethylcarboxamide adenosine (NECA) (10 µM; agonist for all adenosine receptor subtypes) and CGS21680 (10 µM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. Results 1) 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; 2) DPSPX nearly eliminated the inhibitory effects of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; 3) CCPA did not affect LPS-induced TNF-α and CXCL10; 4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. Conclusions 2’,3’-cAMP and its metabolites (3’-AMP, 2’-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. PMID:25451117

Multiple Facets of cAMP Signalling and Physiological Impact: cAMP Compartmentalization in the Lung

PubMed Central

Oldenburger, Anouk; Maarsingh, Harm; Schmidt, Martina

2012-01-01

Therapies involving elevation of the endogenous suppressor cyclic AMP (cAMP) are currently used in the treatment of several chronic inflammatory disorders, including chronic obstructive pulmonary disease (COPD). Characteristics of COPD are airway obstruction, airway inflammation and airway remodelling, processes encompassed by increased airway smooth muscle mass, epithelial changes, goblet cell and submucosal gland hyperplasia. In addition to inflammatory cells, airway smooth muscle cells and (myo)fibroblasts, epithelial cells underpin a variety of key responses in the airways such as inflammatory cytokine release, airway remodelling, mucus hypersecretion and airway barrier function. Cigarette smoke, being next to environmental pollution the main cause of COPD, is believed to cause epithelial hyperpermeability by disrupting the barrier function. Here we will focus on the most recent progress on compartmentalized signalling by cAMP. In addition to G protein-coupled receptors, adenylyl cyclases, cAMP-specific phospho-diesterases (PDEs) maintain compartmentalized cAMP signalling. Intriguingly, spatially discrete cAMP-sensing signalling complexes seem also to involve distinct members of the A-kinase anchoring (AKAP) superfamily and IQ motif containing GTPase activating protein (IQGAPs). In this review, we will highlight the interaction between cAMP and the epithelial barrier to retain proper lung function and to alleviate COPD symptoms and focus on the possible molecular mechanisms involved in this process. Future studies should include the development of cAMP-sensing multiprotein complex specific disruptors and/or stabilizers to orchestrate cellular functions. Compartmentalized cAMP signalling regulates important cellular processes in the lung and may serve as a therapeutic target. PMID:24281338

Experiment definition studies for AMPS Spacelab

NASA Technical Reports Server (NTRS)

Liemohn, H.

1975-01-01

The electrical charging of the space shuttle orbiter is discussed in relation to the AMPS Spacelab payload along with an operations research technique for the selection of AMPS Spacelab experiments. Experiments proposed for AMPS include: hydromagnetic wave experiments; bistatic sounder of AMPS wake; and an artificial meteor gun. Experiment objectives and instrument functions are given for all experiments.

Enzymatic Characterization of AMP Phosphorylase and Ribose-1,5-Bisphosphate Isomerase Functioning in an Archaeal AMP Metabolic Pathway

PubMed Central

Aono, Riku; Sato, Takaaki; Yano, Ayumu; Yoshida, Shosuke; Nishitani, Yuichi; Miki, Kunio; Imanaka, Tadayuki

2012-01-01

AMP phosphorylase (AMPpase), ribose-1,5-bisphosphate (R15P) isomerase, and type III ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) have been proposed to constitute a novel pathway involved in AMP metabolism in the Archaea. Here we performed a biochemical examination of AMPpase and R15P isomerase from Thermococcus kodakarensis. R15P isomerase was specific for the α-anomer of R15P and did not recognize other sugar compounds. We observed that activity was extremely low with the substrate R15P alone but was dramatically activated in the presence of AMP. Using AMP-activated R15P isomerase, we reevaluated the substrate specificity of AMPpase. AMPpase exhibited phosphorylase activity toward CMP and UMP in addition to AMP. The [S]-v plot (plot of velocity versus substrate concentration) of the enzyme toward AMP was sigmoidal, with an increase in activity observed at concentrations higher than approximately 3 mM. The behavior of the two enzymes toward AMP indicates that the pathway is intrinsically designed to prevent excess degradation of intracellular AMP. We further examined the formation of 3-phosphoglycerate from AMP, CMP, and UMP in T. kodakarensis cell extracts. 3-Phosphoglycerate generation was observed from AMP alone, and from CMP or UMP in the presence of dAMP, which also activates R15P isomerase. 3-Phosphoglycerate was not formed when 2-carboxyarabinitol 1,5-bisphosphate, a Rubisco inhibitor, was added. The results strongly suggest that these enzymes are actually involved in the conversion of nucleoside monophosphates to 3-phosphoglycerate in T. kodakarensis. PMID:23065974

Atmospheric, Magnetospheric and Plasmas in space (AMPS) spacelab payload definition study. Volume 4. Part 1, AMPS program specification

NASA Technical Reports Server (NTRS)

Keeley, J. T.

1976-01-01

The AMPS Program Specification delineates the AMPS Program requirements consistent with the resources defined in the AMPS Project Plan. All subsidiary specifications and requirements shall conform to the requirements presented. The requirements hierarchy for the AMPS program is illustrated. A brief description of each of the requirements documents and their intended use is provided.

Design and Experiment of Electrooculogram (EOG) System and Its Application to Control Mobile Robot

NASA Astrophysics Data System (ADS)

Sanjaya, W. S. M.; Anggraeni, D.; Multajam, R.; Subkhi, M. N.; Muttaqien, I.

2017-03-01

In this paper, we design and investigate a biological signal detection of eye movements (Electrooculogram). To detect a signal of Electrooculogram (EOG) used 4 instrument amplifier process; differential instrumentation amplifier, High Pass Filter (HPF) with 3 stage filters, Low Pass Filter (LPF) with 3 stage filters and Level Shifter circuit. The total of amplifying is 1000 times of gain, with frequency range 0.5-30 Hz. IC OP-Amp OP07 was used for all amplifying process. EOG signal will be read as analog input for Arduino microprocessor, and will interfaced with serial communication to PC Monitor using Processing® software. The result of this research show a differences value of eye movements. Differences signal of EOG have been applied to navigation control of the mobile robot. In this research, all communication process using Bluetooth HC-05.

Mechanisms Restricting Diffusion of Intracellular cAMP.

PubMed

Agarwal, Shailesh R; Clancy, Colleen E; Harvey, Robert D

2016-01-22

Although numerous receptors stimulate cAMP production in a wide array of cells, many elicit distinct, highly localized responses, implying that the subcellular distribution of cAMP is not uniform. One often used explanation is that phosphodiesterases, which breakdown cAMP, act as functional barriers limiting diffusion. However, several studies refute the notion that this is sufficient, suggesting that phosphodiesterase-independent movement of cAMP must occur at rates slower than free diffusion. But, until now this has never been demonstrated. Using Raster Image Correlation Spectroscopy (RICS), we measured the diffusion coefficient of a fluorescently-labeled cAMP derivative (φ450-cAMP) as well as other fluorescent molecules in order to investigate the role that molecular size, cell morphology, and buffering by protein kinase A (PKA) play in restricting cAMP mobility in different cell types. Our results demonstrate that cytosolic movement of cAMP is indeed much slower than the rate of free diffusion and that interactions with PKA, especially type II PKA associated with mitochondria, play a significant role. These findings have important implications with respect to cAMP signaling in all cells.

Mechanisms Restricting Diffusion of Intracellular cAMP

PubMed Central

Agarwal, Shailesh R.; Clancy, Colleen E.; Harvey, Robert D.

2016-01-01

Although numerous receptors stimulate cAMP production in a wide array of cells, many elicit distinct, highly localized responses, implying that the subcellular distribution of cAMP is not uniform. One often used explanation is that phosphodiesterases, which breakdown cAMP, act as functional barriers limiting diffusion. However, several studies refute the notion that this is sufficient, suggesting that phosphodiesterase-independent movement of cAMP must occur at rates slower than free diffusion. But, until now this has never been demonstrated. Using Raster Image Correlation Spectroscopy (RICS), we measured the diffusion coefficient of a fluorescently-labeled cAMP derivative (φ450-cAMP) as well as other fluorescent molecules in order to investigate the role that molecular size, cell morphology, and buffering by protein kinase A (PKA) play in restricting cAMP mobility in different cell types. Our results demonstrate that cytosolic movement of cAMP is indeed much slower than the rate of free diffusion and that interactions with PKA, especially type II PKA associated with mitochondria, play a significant role. These findings have important implications with respect to cAMP signaling in all cells. PMID:26795432

R&D100: IC ID

ScienceCinema

Hamlet, Jason; Pierson, Lyndon; Bauer, Todd

2018-06-25

Supply chain security to detect, deter, and prevent the counterfeiting of networked and stand-alone integrated circuits (ICs) is critical to cyber security. Sandia National Laboratory researchers have developed IC ID to leverage Physically Unclonable Functions (PUFs) and strong cryptographic authentication to create a unique fingerprint for each integrated circuit. IC ID assures the authenticity of ICs to prevent tampering or malicious substitution.

AMP sensing by DEAD-box RNA helicases

PubMed Central

Putnam, Andrea A.; Jankowsky, Eckhard

2013-01-01

In eukaryotes, cellular levels of adenosine monophosphate (AMP) signal the metabolic state of the cell. AMP concentrations increase significantly upon metabolic stress, such as glucose deprivation in yeast. Here we show that several DEAD-box RNA helicases are sensitive to AMP, which is not produced during ATP hydrolysis by these enzymes. We find that AMP potently inhibits RNA binding and unwinding by the yeast DEAD-box helicases Ded1p, Mss116p, and eIF4A. However, the yeast DEAD-box helicases Sub2p and Dbp5p are not inhibited by AMP. Our observations identify a subset of DEAD-box helicases as enzymes with the capacity to directly link changes in AMP concentrations to RNA metabolism. PMID:23702290

AMP is an adenosine A1 receptor agonist.

PubMed

Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J

2012-02-17

Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.

AMP sensing by DEAD-box RNA helicases.

PubMed

Putnam, Andrea A; Jankowsky, Eckhard

2013-10-23

In eukaryotes, cellular levels of adenosine monophosphate (AMP) signal the metabolic state of the cell. AMP concentrations increase significantly upon metabolic stress, such as glucose deprivation in yeast. Here, we show that several DEAD-box RNA helicases are sensitive to AMP, which is not produced during ATP hydrolysis by these enzymes. We find that AMP potently inhibits RNA binding and unwinding by the yeast DEAD-box helicases Ded1p, Mss116p, and eIF4A. However, the yeast DEAD-box helicases Sub2p and Dbp5p are not inhibited by AMP. Our observations identify a subset of DEAD-box helicases as enzymes with the capacity to directly link changes in AMP concentrations to RNA metabolism. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phloretin differentially inhibits volume-sensitive and cyclic AMP-activated, but not Ca-activated, Cl− channels

PubMed Central

Fan, Hai-Tian; Morishima, Shigeru; Kida, Hajime; Okada, Yasunobu

2001-01-01

Some phenol derivatives are known to block volume-sensitive Cl− channels. However, effects on the channel of the bisphenol phloretin, which is a known blocker of glucose uniport and anion antiport, have not been examined. In the present study, we investigated the effects of phloretin on volume-sensitive Cl− channels in comparison with cyclic AMP-activated CFTR Cl− channels and Ca2+-activated Cl− channels using the whole-cell patch-clamp technique.Extracellular application of phloretin (over 10 μM) voltage-independently, and in a concentration-dependent manner (IC50 ∼30 μM), inhibited the Cl− current activated by a hypotonic challenge in human epithelial T84, Intestine 407 cells and mouse mammary C127/CFTR cells.In contrast, at 30 μM phloretin failed to inhibit cyclic AMP-activated Cl− currents in T84 and C127/CFTR cells. Higher concentrations (over 100 μM) of phloretin, however, partially inhibited the CFTR Cl− currents in a voltage-dependent manner.At 30 and 300 μM, phloretin showed no inhibitory effect on Ca2+-dependent Cl− currents induced by ionomycin in T84 cells.It is concluded that phloretin preferentially blocks volume-sensitive Cl− channels at low concentrations (below 100 μM) and also inhibits cyclic AMP-activated Cl− channels at higher concentrations, whereas phloretin does not inhibit Ca2+-activated Cl− channels in epithelial cells. PMID:11487521

The 2′,3′-cAMP-adenosine pathway

PubMed Central

2011-01-01

Our recent studies employing HPLC-tandem mass spectrometry to analyze venous perfusate from isolated, perfused kidneys demonstrate that intact kidneys produce and release into the extracellular compartment 2′,3′-cAMP, a positional isomer of the second messenger 3′,5′-cAMP. To our knowledge, this represents the first detection of 2′,3′-cAMP in any cell/tissue/organ/organism. Nuclear magnetic resonance experiments with isolated RNases and experiments in isolated, perfused kidneys suggest that 2′,3′-cAMP likely arises from RNase-mediated transphosphorylation of mRNA. Both in vitro and in vivo kidney experiments demonstrate that extracellular 2′,3′-cAMP is efficiently metabolized to 2′-AMP and 3′-AMP, both of which can be further metabolized to adenosine. This sequence of reactions is called the 2′,3′-cAMP-adenosine pathway (2′,3′-cAMP → 2′-AMP/3′-AMP → adenosine). Experiments in rat and mouse kidneys show that metabolic poisons increase extracellular levels of 2′,3′-cAMP, 2′-AMP, 3′-AMP, and adenosine; however, little is known regarding the pharmacology of 2′,3′-cAMP, 2′-AMP, and 3′-AMP. What is known is that 2′,3′-cAMP facilitates activation of mitochondrial permeability transition pores, a process that can lead to apoptosis and necrosis, and inhibits proliferation of vascular smooth muscle cells and glomerular mesangial cells. In summary, there is mounting evidence that at least some types of cellular injury, by triggering mRNA degradation, engage the 2′,3′-cAMP-adenosine pathway, and therefore this pathway should be added to the list of biochemical pathways that produce adenosine. Although speculative, it is possible that the 2′,3′-cAMP-adenosine pathway may protect against some forms of acute organ injury, for example acute kidney injury, by both removing an intracellular toxin (2′,3′-cAMP) and increasing an extracellular renoprotectant (adenosine). PMID:21937608

Understanding cAMP-dependent allostery by NMR spectroscopy: comparative analysis of the EPAC1 cAMP-binding domain in its apo and cAMP-bound states.

PubMed

Mazhab-Jafari, Mohammad T; Das, Rahul; Fotheringham, Steven A; SilDas, Soumita; Chowdhury, Somenath; Melacini, Giuseppe

2007-11-21

cAMP (adenosine 3',5'-cyclic monophosphate) is a ubiquitous second messenger that activates a multitude of essential cellular responses. Two key receptors for cAMP in eukaryotes are protein kinase A (PKA) and the exchange protein directly activated by cAMP (EPAC), which is a recently discovered guanine nucleotide exchange factor (GEF) for the small GTPases Rap1 and Rap2. Previous attempts to investigate the mechanism of allosteric activation of eukaryotic cAMP-binding domains (CBDs) at atomic or residue resolution have been hampered by the instability of the apo form, which requires the use of mixed apo/holo systems, that have provided only a partial picture of the CBD apo state and of the allosteric networks controlled by cAMP. Here, we show that, unlike other eukaryotic CBDs, both apo and cAMP-bound states of the EPAC1 CBD are stable under our experimental conditions, providing a unique opportunity to define at an unprecedented level of detail the allosteric interactions linking two critical functional sites of this CBD. These are the phosphate binding cassette (PBC), where cAMP binds, and the N-terminal helical bundle (NTHB), which is the site of the inhibitory interactions between the regulatory and catalytic regions of EPAC. Specifically, the combined analysis of the cAMP-dependent changes in chemical shifts, 2 degrees structure probabilities, hydrogen/hydrogen exchange (H/H) and hydrogen/deuterium exchange (H/D) protection factors reveals that the long-range communication between the PBC and the NTHB is implemented by two distinct intramolecular cAMP-signaling pathways, respectively, mediated by the beta2-beta3 loop and the alpha6 helix. Docking of cAMP into the PBC perturbs the NTHB inner core packing and the helical probabilities of selected NTHB residues. The proposed model is consistent with the allosteric role previously hypothesized for L273 and F300 based on site-directed mutagenesis; however, our data show that such a contact is part of a

AMP Is an Adenosine A1 Receptor Agonist*

PubMed Central

Rittiner, Joseph E.; Korboukh, Ilia; Hull-Ryde, Emily A.; Jin, Jian; Janzen, William P.; Frye, Stephen V.; Zylka, Mark J.

2012-01-01

Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5′-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5′-monophosphonate, ACP) directly activated the adenosine A1 receptor (A1R). In contrast, AMP only activated the adenosine A2B receptor (A2BR) after hydrolysis to adenosine by ecto-5′-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A1R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A1R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A1R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A1R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine. PMID:22215671

Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions.

PubMed

Schmidt, Martina; Dekker, Frank J; Maarsingh, Harm

2013-04-01

Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.

cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP).

PubMed

Roberts, Owain Llŷr; Dart, Caroline

2014-02-01

The second messenger cAMP plays a central role in mediating vascular smooth muscle relaxation in response to vasoactive transmitters and in strengthening endothelial cell-cell junctions that regulate the movement of solutes, cells and macromolecules between the blood and the surrounding tissue. The vasculature expresses three cAMP effector proteins: PKA (protein kinase A), CNG (cyclic-nucleotide-gated) ion channels, and the most recently discovered Epacs (exchange proteins directly activated by cAMP). Epacs are a family of GEFs (guanine-nucleotide-exchange factors) for the small Ras-related GTPases Rap1 and Rap2, and are being increasingly implicated as important mediators of cAMP signalling, both in their own right and in parallel with the prototypical cAMP target PKA. In the present paper, we review what is currently known about the role of Epac within blood vessels, particularly with regard to the regulation of vascular tone, endothelial barrier function and inflammation.

Cloning and characterization of a cAMP-specific phosphodiesterase (TbPDE2B) from Trypanosoma brucei

PubMed Central

Rascón, Ana; Soderling, Scott H.; Schaefer, Jonathan B.; Beavo, Joseph A.

2002-01-01

Here we report the cloning, expression, and characterization of a cAMP-specific phosphodiesterase (PDE) from Trypanosoma brucei (TbPDE2B). Using a bioinformatic approach, two different expressed sequence tag clones were identified and used to isolate the complete sequence of two identical PDE genes arranged in tandem. Each gene consists of 2,793 bases that predict a protein of 930 aa with a molecular mass of 103.2 kDa. Two GAF (for cGMP binding and stimulated PDEs, Anabaena adenylyl cyclases, and Escherichia coli FhlA) domains, similar to those contained in many signaling molecules including mammalian PDE2, PDE5, PDE6, PDE10, and PDE11, were located N-terminal to a consensus PDE catalytic domain. The catalytic domain is homologous to the catalytic domain of all 11 mammalian PDEs, the Dictyostelium discoideum RegA, and a probable PDE from Caenorhabditis elegans. It is most similar to the T. brucei PDE2A (89% identity). TbPDE2B has substrate specificity for cAMP with a Km of 2.4 μM. cGMP is not hydrolyzed by TbPDE2B nor does this cyclic nucleotide modulate cAMP PDE activity. The nonselective PDE inhibitors 3-isobutyl-1-methylxanthine, papaverine and pentoxifyline are poor inhibitors of TbPDE2B. Similarly, PDE inhibitors selective for the mammalian PDE families 2, 3, 5, and 6 (erythro-9-[3-(2-hydroxynonyl)]-adenine, enoximone, zaprinast, and sildenafil) were also unable to inhibit this enzyme. However, dipyridamole was a reasonably good inhibitor of this enzyme with an IC50 of 27 μM. cAMP plays key roles in cell growth and differentiation in this parasite, and PDEs are responsible for the hydrolysis of this important second messenger. Therefore, parasite PDEs, including this one, have the potential to be attractive targets for selective drug design. PMID:11930017

42 CFR 447.504 - Determination of AMP.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Determination of AMP. 447.504 Section 447.504 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS PAYMENTS FOR SERVICES Payment for Drugs § 447.504 Determination of AMP. (a) AMP means, with respect to a covered...

Investigation into the common mode rejection ratio of the physiological signal conditioner circuit

NASA Technical Reports Server (NTRS)

Obrien, Edward M.

1992-01-01

The common mode rejection ratio (CMRR) of the single operational amplifier (op amp) differential amplifier and of the three operational amplifier differential amplifier was investigated. The three op amp differential amplifier circuit is used in the signal conditioner circuit which amplifies signals such as the electromyograph or electrocardiogram. The investigation confirmed via SPICE modeling what has been observed by others in the recent literature that the CMRR for the circuit can be maximized without precision resistor values or precisely matched op amps. This can be done if one resistor in the final stage can be adjusted either by a potentiometer or by laser trimming in the case of hybrid circuit fabrication.

Integrated Circuit Design of 3 Electrode Sensing System Using Two-Stage Operational Amplifier

NASA Astrophysics Data System (ADS)

Rani, S.; Abdullah, W. F. H.; Zain, Z. M.; N, Aqmar N. Z.

2018-03-01

This paper presents the design of a two-stage operational amplifier(op amp) for 3-electrode sensing system readout circuits. The designs have been simulated using 0.13μm CMOS technology from Silterra (Malaysia) with Mentor graphics tools. The purpose of this projects is mainly to design a miniature interfacing circuit to detect the redox reaction in the form of current using standard analog modules. The potentiostat consists of several op amps combined together in order to analyse the signal coming from the 3-electrode sensing system. This op amp design will be used in potentiostat circuit device and to analyse the functionality for each module of the system.

Hardware implementation of an adaptive resonance theory (ART) neural network using compensated operational amplifiers

NASA Astrophysics Data System (ADS)

Ho, Ching S.; Liou, Juin J.; Georgiopoulos, Michael; Christodoulou, Christos G.

1994-03-01

This paper presents an analog circuit design and implementation for an adaptive resonance theory neural network architecture called the augmented ART1 neural network (AART1-NN). Practical monolithic operational amplifiers (Op-Amps) LM741 and LM318 are selected to implement the circuit, and a simple compensation scheme is developed to adjust the Op-Amp electrical characteristics to meet the design requirement. A 7-node prototype circuit has been designed and verified using the Pspice circuit simulator run on a Sun workstation. Results simulated from the AART1-NN circuit using the LM741, LM318, and ideal Op-Amps are presented and compared.

Cyclic AMP Inhibits the Activity and Promotes the Acetylation of Acetyl-CoA Synthetase through Competitive Binding to the ATP/AMP Pocket.

PubMed

Han, Xiaobiao; Shen, Liqiang; Wang, Qijun; Cen, Xufeng; Wang, Jin; Wu, Meng; Li, Peng; Zhao, Wei; Zhang, Yu; Zhao, Guoping

2017-01-27

The high-affinity biosynthetic pathway for converting acetate to acetyl-coenzyme A (acetyl-CoA) is catalyzed by the central metabolic enzyme acetyl-coenzyme A synthetase (Acs), which is finely regulated both at the transcriptional level via cyclic AMP (cAMP)-driven trans-activation and at the post-translational level via acetylation inhibition. In this study, we discovered that cAMP directly binds to Salmonella enterica Acs (SeAcs) and inhibits its activity in a substrate-competitive manner. In addition, cAMP binding increases SeAcs acetylation by simultaneously promoting Pat-dependent acetylation and inhibiting CobB-dependent deacetylation, resulting in enhanced SeAcs inhibition. A crystal structure study and site-directed mutagenesis analyses confirmed that cAMP binds to the ATP/AMP pocket of SeAcs, and restrains SeAcs in an open conformation. The cAMP contact residues are well conserved from prokaryotes to eukaryotes, suggesting a general regulatory mechanism of cAMP on Acs. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Atmospheric, Magnetospheric and Plasmas in Space (AMPS) spacelab payload definition study. Volume 3: Interface control documents. Part 2: AMPS payload to spacelab ICD

NASA Technical Reports Server (NTRS)

1976-01-01

The AMPS to Spacelab Interface Control Document which is to be used as a guide for format and information content in generating specific AMPS Mission ICDs is presented. This document is meant to supplement the Spacelab Payload Accommodations Handbook in that it only defines interfaces which are not discussed in the handbook to the level required for design purposes. The AMPS Top Level Requirements Tree, illustrates this ICD by a shaded area and its relationship to the other AMPS technical documents. Other interface documents shown are the Level II, AMPS to Space Shuttle Vehicle ICD and the Level III, AMPS to Instruments ICD.

Exchange protein activated by cAMP (Epac) mediates cAMP-dependent but protein kinase A-insensitive modulation of vascular ATP-sensitive potassium channels

PubMed Central

Purves, Gregor I; Kamishima, Tomoko; Davies, Lowri M; Quayle, John M; Dart, Caroline

2009-01-01

Exchange proteins directly activated by cyclic AMP (Epacs or cAMP-GEF) represent a family of novel cAMP-binding effector proteins. The identification of Epacs and the recent development of pharmacological tools that discriminate between cAMP-mediated pathways have revealed previously unrecognized roles for cAMP that are independent of its traditional target cAMP-dependent protein kinase (PKA). Here we show that Epac exists in a complex with vascular ATP-sensitive potassium (KATP) channel subunits and that cAMP-mediated activation of Epac modulates KATP channel activity via a Ca2+-dependent mechanism involving the activation of Ca2+-sensitive protein phosphatase 2B (PP-2B, calcineurin). Application of the Epac-specific cAMP analogue 8-pCPT-2′-O-Me-cAMP, at concentrations that activate Epac but not PKA, caused a 41.6 ± 4.7% inhibition (mean ±s.e.m.; n= 7) of pinacidil-evoked whole-cell KATP currents recorded in isolated rat aortic smooth muscle cells. Importantly, similar results were obtained when cAMP was elevated by addition of the adenylyl cyclase activator forskolin in the presence of the structurally distinct PKA inhibitors, Rp-cAMPS or KT5720. Activation of Epac by 8-pCPT-2′-O-Me-cAMP caused a transient 171.0 ± 18.0 nm (n= 5) increase in intracellular Ca2+ in Fura-2-loaded aortic myocytes, which persisted in the absence of extracellular Ca2+. Inclusion of the Ca2+-specific chelator BAPTA in the pipette-filling solution or preincubation with the calcineurin inhibitors, cyclosporin A or ascomycin, significantly reduced the ability of 8-pCPT-2′-O-Me-cAMP to inhibit whole-cell KATP currents. These results highlight a previously undescribed cAMP-dependent regulatory mechanism that may be essential for understanding the physiological and pathophysiological roles ascribed to arterial KATP channels in the control of vascular tone and blood flow. PMID:19491242

Intracellular tortuosity underlies slow cAMP diffusion in adult ventricular myocytes.

PubMed

Richards, Mark; Lomas, Oliver; Jalink, Kees; Ford, Kerrie L; Vaughan-Jones, Richard D; Lefkimmiatis, Konstantinos; Swietach, Pawel

2016-06-01

3',5'-Cyclic adenosine monophosphate (cAMP) signals in the heart are often confined to concentration microdomains shaped by cAMP diffusion and enzymatic degradation. While the importance of phosphodiesterases (degradative enzymes) in sculpting cAMP microdomains is well established in cardiomyocytes, less is known about cAMP diffusivity (DcAMP) and factors affecting it. Many earlier studies have reported fast diffusivity, which argues against sharply defined microdomains. [cAMP] dynamics in the cytoplasm of adult rat ventricular myocytes were imaged using a fourth generation genetically encoded FRET-based sensor. The [cAMP]-response to the addition and removal of isoproterenol (β-adrenoceptor agonist) quantified the rates of cAMP synthesis and degradation. To obtain a read out of DcAMP, a stable [cAMP] gradient was generated using a microfluidic device which delivered agonist to one half of the myocyte only. After accounting for phosphodiesterase activity, DcAMP was calculated to be 32 µm(2)/s; an order of magnitude lower than in water. Diffusivity was independent of the amount of cAMP produced. Saturating cAMP-binding sites with the analogue 6-Bnz-cAMP did not accelerate DcAMP, arguing against a role of buffering in restricting cAMP mobility. cAMP diffused at a comparable rate to chemically unrelated but similar sized molecules, arguing for a common physical cause of restricted diffusivity. Lower mitochondrial density and order in neonatal cardiac myocytes allowed for faster diffusion, demonstrating the importance of mitochondria as physical barriers to cAMP mobility. In adult cardiac myocytes, tortuosity due to physical barriers, notably mitochondria, restricts cAMP diffusion to levels that are more compatible with microdomain signalling. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.

C++ Coding Standards for the AMP Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, Thomas M; Clarno, Kevin T

2009-09-01

This document provides an initial starting point to define the C++ coding standards used by the AMP nuclear fuel performance integrated code project and a part of AMP's software development process. This document draws from the experiences, and documentation [1], of the developers of the Marmot Project at Los Alamos National Laboratory. Much of the software in AMP will be written in C++. The power of C++ can be abused easily, resulting in code that is difficult to understand and maintain. This document gives the practices that should be followed on the AMP project for all new code that ismore » written. The intent is not to be onerous but to ensure that the code can be readily understood by the entire code team and serve as a basis for collectively defining a set of coding standards for use in future development efforts. At the end of the AMP development in fiscal year (FY) 2010, all developers will have experience with the benefits, restrictions, and limitations of the standards described and will collectively define a set of standards for future software development. External libraries that AMP uses do not have to meet these requirements, although we encourage external developers to follow these practices. For any code of which AMP takes ownership, the project will decide on any changes on a case-by-case basis. The practices that we are using in the AMP project have been in use in the Denovo project [2] for several years. The practices build on those given in References [3-5]; the practices given in these references should also be followed. Some of the practices given in this document can also be found in [6].« less

Positive Effect of Carbon Sources on Natural Transformation in Escherichia coli: Role of Low-Level Cyclic AMP (cAMP)-cAMP Receptor Protein in the Derepression of rpoS

PubMed Central

Guo, Mengyue; Wang, Huanyu; Xie, Nengbin

2015-01-01

ABSTRACT Natural plasmid transformation of Escherichia coli is a complex process that occurs strictly on agar plates and requires the global stress response factor σS. Here, we showed that additional carbon sources could significantly enhance the transformability of E. coli. Inactivation of phosphotransferase system genes (ptsH, ptsG, and crr) caused an increase in the transformation frequency, and the addition of cyclic AMP (cAMP) neutralized the promotional effect of carbon sources. This implies a negative role of cAMP in natural transformation. Further study showed that crp and cyaA mutations conferred a higher transformation frequency, suggesting that the cAMP-cAMP receptor protein (CRP) complex has an inhibitory effect on transformation. Moreover, we observed that rpoS is negatively regulated by cAMP-CRP in early log phase and that both crp and cyaA mutants show no transformation superiority when rpoS is knocked out. Therefore, it can be concluded that both the crp and cyaA mutations derepress rpoS expression in early log phase, whereby they aid in the promotion of natural transformation ability. We also showed that the accumulation of RpoS during early log phase can account for the enhanced transformation aroused by additional carbon sources. Our results thus demonstrated that the presence of additional carbon sources promotes competence development and natural transformation by reducing cAMP-CRP and, thus, derepressing rpoS expression during log phase. This finding could contribute to a better understanding of the relationship between nutrition state and competence, as well as the mechanism of natural plasmid transformation in E. coli. IMPORTANCE Escherichia coli, which is not usually considered to be naturally transformable, was found to spontaneously take up plasmid DNA on agar plates. Researching the mechanism of natural transformation is important for understanding the role of transformation in evolution, as well as in the transfer of pathogenicity and

7 CFR 772.14 - Reamortization of AMP loans.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Reamortization of AMP loans. 772.14 Section 772.14... AGRICULTURE SPECIAL PROGRAMS SERVICING MINOR PROGRAM LOANS § 772.14 Reamortization of AMP loans. The Agency may approve reamortization of AMP loans provided: (a) There is no extension of the final maturity date...

Cyclic AMP efflux inhibitors as potential therapeutic agents for leukemia.

PubMed

Perez, Dominique R; Smagley, Yelena; Garcia, Matthew; Carter, Mark B; Evangelisti, Annette; Matlawska-Wasowska, Ksenia; Winter, Stuart S; Sklar, Larry A; Chigaev, Alexandre

2016-06-07

Apoptotic evasion is a hallmark of cancer. We propose that some cancers may evade cell death by regulating 3'-5'-cyclic adenosine monophosphate (cAMP), which is associated with pro-apoptotic signaling. We hypothesize that leukemic cells possess mechanisms that efflux cAMP from the cytoplasm, thus protecting them from apoptosis. Accordingly, cAMP efflux inhibition should result in: cAMP accumulation, activation of cAMP-dependent downstream signaling, viability loss, and apoptosis. We developed a novel assay to assess cAMP efflux and performed screens to identify inhibitors. In an acute myeloid leukemia (AML) model, several identified compounds reduced cAMP efflux, appropriately modulated pathways that are responsive to cAMP elevation (cAMP-responsive element-binding protein phosphorylation, and deactivation of Very Late Antigen-4 integrin), and induced mitochondrial depolarization and caspase activation. Blocking adenylyl cyclase activity was sufficient to reduce effects of the most potent compounds. These compounds also decreased cAMP efflux and viability of B-lineage acute lymphoblastic leukemia (B-ALL) cell lines and primary patient samples, but not of normal primary peripheral blood mononuclear cells. Our data suggest that cAMP efflux is a functional feature that could be therapeutically targeted in leukemia. Furthermore, because some of the identified drugs are currently used for treating other illnesses, this work creates an opportunity for repurposing.

AMPS Supporting Research and Technology (SR and T) report. Atmospheric, Magnetospheric and Plasmas in Space (AMPS) definition study

NASA Technical Reports Server (NTRS)

1976-01-01

A listing of candidate technology areas that require additional study is presented. These candidate tasks, identified during the AMPS Phase B studies, are requisites to the design, development, and operation of the AMPS concept selected for preliminary design.

Structural and Functional Characterization of Pseudomonas aeruginosa Global Regulator AmpR

PubMed Central

Caille, Olivier; Zincke, Diansy; Merighi, Massimo; Balasubramanian, Deepak; Kumari, Hansi; Kong, Kok-Fai; Silva-Herzog, Eugenia; Narasimhan, Giri; Schneper, Lisa; Lory, Stephen

2014-01-01

Pseudomonas aeruginosa is a dreaded pathogen in many clinical settings. Its inherent and acquired antibiotic resistance thwarts therapy. In particular, derepression of the AmpC β-lactamase is a common mechanism of β-lactam resistance among clinical isolates. The inducible expression of ampC is controlled by the global LysR-type transcriptional regulator (LTTR) AmpR. In the present study, we investigated the genetic and structural elements that are important for ampC induction. Specifically, the ampC (PampC) and ampR (PampR) promoters and the AmpR protein were characterized. The transcription start sites (TSSs) of the divergent transcripts were mapped using 5′ rapid amplification of cDNA ends-PCR (RACE-PCR), and strong σ54 and σ70 consensus sequences were identified at PampR and PampC, respectively. Sigma factor RpoN was found to negatively regulate ampR expression, possibly through promoter blocking. Deletion mapping revealed that the minimal PampC extends 98 bp upstream of the TSS. Gel shifts using membrane fractions showed that AmpR binds to PampC in vitro whereas in vivo binding was demonstrated using chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR). Additionally, site-directed mutagenesis of the AmpR helix-turn-helix (HTH) motif identified residues critical for binding and function (Ser38 and Lys42) and critical for function but not binding (His39). Amino acids Gly102 and Asp135, previously implicated in the repression state of AmpR in the enterobacteria, were also shown to play a structural role in P. aeruginosa AmpR. Alkaline phosphatase fusion and shaving experiments suggest that AmpR is likely to be membrane associated. Lastly, an in vivo cross-linking study shows that AmpR dimerizes. In conclusion, a potential membrane-associated AmpR dimer regulates ampC expression by direct binding. PMID:25182487

Modafinil inhibits K(Ca)3.1 currents and muscle contraction via a cAMP-dependent mechanism.

PubMed

Choi, Shinkyu; Kim, Moon Young; Joo, Ka Young; Park, Seonghee; Kim, Ji Aee; Jung, Jae-Chul; Oh, Seikwan; Suh, Suk Hyo

2012-07-01

Modafinil has been used as a psychostimulant for the treatment of narcolepsy. However, its primary mechanism of action remains elusive. Therefore, we examined the effects of modafinil on K(Ca)3.1 channels and vascular smooth muscle contraction. K(Ca)3.1 currents and channel activity were measured using a voltage-clamp technique and inside-out patches in mouse embryonic fibroblast cell line, NIH-3T3 fibroblasts. Intracellular adenosine 3',5'-cyclic monophosphate (cAMP) concentration was measured, and the phosphorylation of K(Ca)3.1 channel protein was examined using western blotting in NIH-3T3 fibroblasts and/or primary cultured mouse aortic smooth muscle cells (SMCs). Muscle contractions were recorded from mouse aorta and rat pulmonary artery by using a myograph developed in-house. Modafinil was found to inhibit K(Ca)3.1 currents in a concentration-dependent manner, and the half-maximal inhibition (IC(50)) of modafinil for the current inhibition was 6.8 ± 0.7 nM. The protein kinase A (PKA) activator forskolin also inhibited K(Ca)3.1 currents. The inhibitory effects of modafinil and forskolin on K(Ca)3.1 currents were blocked by the PKA inhibitors PKI(14-22) or H-89. In addition, modafinil relaxed blood vessels (mouse aorta and rat pulmonary artery) in a concentration-dependent manner. Modafinil increased cAMP concentrations in NIH-3T3 fibroblasts or primary cultured mouse aortic SMCs and phosphorylated K(Ca)3.1 channel protein in NIH-3T3 fibroblasts. However, open probability and single-channel current amplitudes of K(Ca)3.1 channels were not changed by modafinil. From these results, we conclude that modafinil inhibits K(Ca)3.1 channels and vascular smooth muscle contraction by cAMP-dependent phosphorylation, suggesting that modafinil can be used as a cAMP-dependent K(Ca)3.1 channel blocker and vasodilator. Copyright © 2012 Elsevier Ltd. All rights reserved.

Hardness Assurance Techniques for New Generation COTS Devices

NASA Technical Reports Server (NTRS)

Lee, C. I.; Rax, B. G.; Johnston, A. H.

1996-01-01

Hardness Assurance (HA) techniques and total dose radiation characterization data for new generation linear and COTS devices from various manufacturers are presented. A bipolar op amp showed significant degradation at HDR, not at low dose rate environment. New generation low-power op amps showed more degradation at low voltage applications. HA test techniques for COTS devices are presented in this paper.

Add-on LABA in a separate inhaler as asthma step-up therapy versus increased dose of ICS or ICS/LABA combination inhaler.

PubMed

Price, David B; Colice, Gene; Israel, Elliot; Roche, Nicolas; Postma, Dirkje S; Guilbert, Theresa W; van Aalderen, Willem M C; Grigg, Jonathan; Hillyer, Elizabeth V; Thomas, Victoria; Martin, Richard J

2016-04-01

Asthma management guidelines recommend adding a long-acting β 2 -agonist (LABA) or increasing the dose of inhaled corticosteroid (ICS) as step-up therapy for patients with uncontrolled asthma on ICS monotherapy. However, it is uncertain which option works best, which ICS particle size is most effective, and whether LABA should be administered by separate or combination inhalers. This historical, matched cohort study compared asthma-related outcomes for patients (aged 12-80 years) prescribed step-up therapy as a ≥50% extrafine ICS dose increase or add-on LABA, via either a separate inhaler or a fine-particle ICS/LABA fixed-dose combination (FDC) inhaler. Risk-domain asthma control was the primary end-point in comparisons of cohorts matched for asthma severity and control during the baseline year. After 1:2 cohort matching, the increased extrafine ICS versus separate ICS+LABA cohorts included 3232 and 6464 patients, respectively, and the fine-particle ICS/LABA FDC versus separate ICS+LABA cohorts included 7529 and 15 058 patients, respectively (overall mean age 42 years; 61-62% females). Over one outcome year, adjusted OR (95% CI) for achieving asthma control were 1.25 (1.13-1.38) for increased ICS versus separate ICS+LABA and 1.06 (1.05-1.09) for ICS/LABA FDC versus separate ICS+LABA. For patients with asthma, increased dose of extrafine-particle ICS, or add-on LABA via ICS/LABA combination inhaler, is associated with significantly better outcomes than ICS+LABA via separate inhalers.

Interplay among Membrane-Bound Lytic Transglycosylase D1, the CreBC Two-Component Regulatory System, the AmpNG-AmpDI-NagZ-AmpR Regulatory Circuit, and L1/L2 β-Lactamase Expression in Stenotrophomonas maltophilia

PubMed Central

Huang, Yi-Wei; Wu, Chao-Jung; Hu, Rouh-Mei; Lin, Yi-Tsung

2015-01-01

Lytic transglycosylases (LTs) are an important class of enzymes involved in peptidoglycan (PG) cleavage, with the concomitant formation of an intramolecular 1,6-anhydromuramoyl reaction product. There are six annotated LT genes in the Stenotrophomonas maltophilia genome, including genes for five membrane-bound LTs (mltA, mltB1, mltB2, mltD1, and mltD2) and a gene for soluble LT (slt). Six LTs of S. maltophilia KJ were systematically mutated, yielding the ΔmltA, ΔmltB1, ΔmltB2, ΔmltD1, ΔmltD2, and Δslt mutants. Inactivation of mltD1 conferred a phenotype of elevated uninduced β-lactamase activity. The underlying mechanism responsible for this phenotype was elucidated by the construction of several mutants and determination of β-lactamase activity. The expression of the genes assayed was assessed by quantitative reverse transcriptase PCR and a promoter transcription fusion assay. The results demonstrate that ΔmltD1 mutant-mediated L1/L2 β-lactamase expression involved the creBC two-component regulatory system (TCS) and the ampNG-ampDI-nagZ-ampR regulatory circuit. The inactivation of mltD1 resulted in mltB1 and mltD2 upexpression in a creBC- and ampNG-dependent manner. The overexpressed MltB1 and MltD2 activity contributed to the expression of the L1/L2 β-lactamase genes via the ampNG-ampDI-nagZ-ampR regulatory circuit. These findings reveal, for the first time, a linkage between LTs, the CreBC TCS, the ampNG-ampDI-nagZ-ampR regulatory circuit, and L1/L2 β-lactamase expression in S. maltophilia. PMID:26282431

Inhibition of basolateral cAMP permeability in the toad urinary bladder.

PubMed

Boom, A; Golstein, P E; Frerotte, M; Sande, J V; Beauwens, R

2000-10-01

1. The effect of sulphonylurea drugs on hydrosmotic flow across toad urinary bladder epithelium was re-evaluated in the present study. Glibenclamide, added to the basolateral medium, significantly enhanced the osmotic flow induced by low doses of antidiuretic hormone (ADH) or forskolin (FK), while it inhibited the effect of exogenous cyclic adenosine monophosphate (cAMP) or its non-hydrolysable bromo derivative, 8-Br-cAMP, added to the basolateral medium. These opposite effects of glibenclamide on the transepithelial osmotic flow can be explained by a reduction of cAMP permeability across the basolateral membrane of the epithelium. The decrease in cAMP permeability leads, according to the direction of the cAMP gradient, to firstly an enhanced osmotic flow when cAMP is generated intracellularly by addition of ADH and FK, glibenclamide reducing cAMP exit from the cell, and secondly a decreased osmotic flow in response to cAMP (and 8-Br-cAMP) added to the basolateral medium, glibenclamide inhibiting, in this case, their entry into the cell. 2. The demonstration that glibenclamide actually inhibits the basolateral cAMP permeability rests on the fact that firstly it decreases the release of cAMP into the basolateral medium by about 40 %, at each concentration of ADH or forskolin tested, secondly it increases the cAMP content of paired hemibladders incubated in the presence of ADH or FK, when intracellular degradation was prevented by phosphodiesterase inhibition, and thirdly it decreases also the uptake of basolateral 8-Br-[3H]cAMP into paired toad hemibladders. 3. Taken together, the present data demonstrate that glibenclamide inhibits the toad urinary bladder basolateral membrane permeability to cAMP, most probably by a direct interaction with a membrane protein not yet indentified but distinct from the sulphonylurea receptor.

[Physiopathology of cAMP/PKA signaling in neurons].

PubMed

Castro, Liliana; Yapo, Cedric; Vincent, Pierre

2016-01-01

Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, synaptic transmission, regulation of excitability or long term changes in the nucleus. Genetically-encoded optical biosensors for cAMP or PKA considerably improved our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progresses made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the subcellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus and axon. Combining this imaging approach with pharmacology or genetical models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly help understand the mechanism of action of current drugs as well as help in devising novel therapeutic strategies for neuropsychiatric diseases. © Société de Biologie, 2017.

7 CFR 772.10 - Transfer and assumption-AMP loans.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Transfer and assumption-AMP loans. 772.10 Section 772..., DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS SERVICING MINOR PROGRAM LOANS § 772.10 Transfer and assumption—AMP loans. (a) Eligibility. The Agency may approve transfers and assumptions of AMP loans when: (1) The...

Expression profiles of antimicrobial peptides (AMPs) and their regulation by Relish

NASA Astrophysics Data System (ADS)

Wang, Dongdong; Li, Fuhua; Li, Shihao; Wen, Rong; Xiang, Jianhai

2012-07-01

Antimicrobial peptides (AMPs), as key immune effectors, play important roles in the innate immune system of invertebrates. Different types of AMPs, including Penaeidin, Crustin, ALF (antilipopolysaccharide factor) have been identified in different penaeid shrimp; however, systematic analyses on the function of different AMPs in shrimp responsive to different types of bacteria are very limited. In this study, we analyzed the expression profiles of AMPs in the Chinese shrimps, Fenneropenaeus chinensis, simultaneously by real-time RT-PCR (reverse transcription-polymerase chain reaction) when shrimp were challenged with Micrococcus lysodeikticus (Gram-positive, G+) or Vibrio anguillarium (Gram-negative, G-). Different AMPs showed different expression profiles when shrimp were injected with one type of bacterium, and one AMP also showed different expression profiles when shrimp were challenged with different bacteria. Furthermore, the expression of these AMPs showed temporal expression profiles, suggesting that different AMPs function coordinately in bacteria-infected shrimp. An RNA interference approach was used to study the function of the Relish transcription factor in regulating the transcription of different AMPs. The current study showed that Relish could regulate the transcription of different AMPs in shrimp. Differential expression profiles of AMPs in shrimp injected with different types of bacteria indicated that a complicated antimicrobial response network existed in shrimp. These data contribute to our understanding of immunity in shrimp and may provide a strategy for the control of disease in shrimp.

Cyclic AMP regulates formation of mammary epithelial acini in vitro

PubMed Central

Nedvetsky, Pavel I.; Kwon, Sang-Ho; Debnath, Jayanta; Mostov, Keith E.

2012-01-01

Epithelial cells form tubular and acinar structures notable for a hollow lumen. In three-dimensional culture utilizing MCF10A mammary epithelial cells, acini form due to integrin-dependent polarization and survival of cells contacting extracellular matrix (ECM), and the apoptosis of inner cells of acini lacking contact with the ECM. In this paper, we report that cyclic AMP (cAMP)-dependent protein kinase A (PKA) promotes acinus formation via two mechanisms. First, cAMP accelerates redistribution of α6-integrin to the periphery of the acinus and thus facilitates the polarization of outer acinar cells. Blocking of α6-integrin function by inhibitory antibody prevents cAMP-dependent polarization. Second, cAMP promotes the death of inner cells occupying the lumen. In the absence of cAMP, apoptosis is delayed, resulting in perturbed luminal clearance. cAMP-dependent apoptosis is accompanied by a posttranscriptional PKA-dependent increase in the proapoptotic protein Bcl-2 interacting mediator of cell death. These data demonstrate that cAMP regulates lumen formation in mammary epithelial cells in vitro, both through acceleration of polarization of outer cells and apoptosis of inner cells of the acinus. PMID:22675028

The Brain In Vivo Expresses the 2′,3′-cAMP-Adenosine Pathway

PubMed Central

Verrier, Jonathan D.; Jackson, Travis C.; Bansal, Rashmi; Kochanek, Patrick M.; Puccio, Ava M.; Okonkwo, David O.; Jackson, Edwin K.

2012-01-01

Although multiple biochemical pathways produce adenosine, studies suggest that the 2′,3′-cAMP-adenosine pathway (2′,3′-cAMP → 2′-AMP/3′-AMP → adenosine) contributes to adenosine production in some cells/tissues/organs. To determine whether the 2′,3′-cAMP-adenosine pathway exists in vivo in the brain, we delivered to the brain (gray matter and white matter separately) via the inflow perfusate of a microdialysis probe either 2′,3′-cAMP, 3′,5′-cAMP, 2′-AMP, 3′-AMP, or 5′-AMP and measured the recovered metabolites in the microdialysis outflow perfusate with mass spectrometry. In both gray and white matter, 2′,3′-cAMP increased 2′-AMP, 3′-AMP and adenosine, and 3′,5′-cAMP increased 5′-AMP and adenosine. In both brain regions, 2′-AMP, 3-AMP and 5′-AMP were converted to adenosine. Microdialysis experiments in 2′,3′-cyclic nucleotide-3′-phosphodiesterase (CNPase) wild-type mice demonstrated that traumatic brain injury (TBI; controlled cortical impact model) activated the brain 2,3′-cAMP-adenosine pathway; similar experiments in CNPase knockout mice indicated that CNPase was involved in the metabolism of endogenous 2′,3′-cAMP to 2′-AMP and to adenosine. In CSF from TBI patients, 2′,3′-cAMP was significantly increased in the initial 12 hours after injury and strongly correlated with CSF levels of 2′-AMP, 3′-AMP, adenosine and inosine. We conclude that in vivo, 2′,3′-cAMP is converted to 2′-AMP/3′-AMP, and these AMPs are metabolized to adenosine. This pathway exists endogenously in both mice and humans. PMID:22360621

The Design of Operational Amplifier for Low Voltage and Low Current Sound Energy Harvesting System

NASA Astrophysics Data System (ADS)

Fang, Liew Hui; Rahim, Rosemizi Bin Abd; Isa, Muzamir; Idris Syed Hassan, Syed; Ismail, Baharuddin Bin

2018-03-01

The objective of this paper is to design a combination of an operational amplifier (op-amp) with a rectifier used in an alternate current (ac) to direct current (dc) power conversion. The op-amp was designed to specifically work at low voltage and low current for a sound energy harvesting system. The goal of the op-amp design with adjustable gain was to control output voltage based on the objectives of the experiment conducted. The op-amp was designed for minimum power dissipation performance, with the means of increasing the output current when receiving a large amount of load. The harvesting circuits which designed further improved the power output efficiency by shortening the fully charged time needed by a supercapacitor bank. It can fulfil the long-time power demands for low power device. Typically, a small amount of energy sources were converted to electricity and stored in the supercapacitor bank, which was built by 10 pieces of capacitors with 0.22 F each, arranged in parallel connection. The highest capacitance was chosen based on the characteristic that have the longest discharging time to support the applications of a supercapacitor bank. Testing results show that the op-amp can boost the low input ac voltage (∼3.89 V) to high output dc voltage (5.0 V) with output current of 30 mA and stored the electrical energy in a big supercapacitor bank having a total of 2.2 F, effectively. The measured results agree well with the calculated results.

The therapeutic applications of antimicrobial peptides (AMPs): a patent review.

PubMed

Kang, Hee-Kyoung; Kim, Cheolmin; Seo, Chang Ho; Park, Yoonkyung

2017-01-01

Antimicrobial peptides (AMPs) are small molecules with a broad spectrum of antibiotic activities against bacteria, yeasts, fungi, and viruses and cytotoxic activity on cancer cells, in addition to anti-inflammatory and immunomodulatory activities. Therefore, AMPs have garnered interest as novel therapeutic agents. Because of the rapid increase in drug-resistant pathogenic microorganisms, AMPs from synthetic and natural sources have been developed using alternative antimicrobial strategies. This article presents a broad analysis of patents referring to the therapeutic applications of AMPs since 2009. The review focuses on the universal trends in the effective design, mechanism, and biological evolution of AMPs.

AMP-18 Targets p21 to Maintain Epithelial Homeostasis.

PubMed

Chen, Peili; Li, Yan Chun; Toback, F Gary

2015-01-01

Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD). We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP)-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI) mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21 WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

A Fast Response Capability within NOAA/NOS/CO-OPS

DTIC Science & Technology

2007-01-01

A Fast Response Capability within NOAA/NOS/CO-OPS P. B. Burke NOAA/National Ocean Service/CO-OPS 1305 East-West Hwy. Silver Spring, MD 20910...USA pat.burke@noaa.gov T. Graff NOAA/National Ocean Service/CO-OPS 1305 East-West Hwy. Silver Spring, MD 20910 USA tammy.graff@noaa.gov... flotation hull, an instrumentation tower mounted atop the hull and a current meter mount with a mooring attachment. The triangular tower housed two

cAMP Regulation of Airway Smooth Muscle Function

PubMed Central

Billington, Charlotte K.; Ojo, Oluwaseun O.; Penn, Raymond B.; Ito, Satoru

2013-01-01

Agonists activating β2-adrenoceptors (β2ARs) on airway smooth muscle (ASM) are the drug of choice for rescue from acute bronchoconstriction in patients with both asthma and chronic obstructive pulmonary disease (COPD). Moreover, the use of long-acting β-agonists combined with inhaled corticosteroids constitutes an important maintenance therapy for these diseases. β-Agonists are effective bronchodilators due primarily to their ability to antagonize ASM contraction. The presumed cellular mechanism of action involves the generation of intracellular cAMP, which in turn can activate the effector molecules cAMP-dependent protein kinase (PKA) and Epac. Other agents such as prostaglandin E2 and phosphodiesterase inhibitors that also increase intracellular cAMP levels in ASM, can also antagonize ASM contraction, and inhibit other ASM functions including proliferation and migration. Therefore, β2ARs and cAMP are key players in combating the pathophysiology of airway narrowing and remodeling. However, limitations of β-agonist therapy due to drug tachyphylaxis related to β2AR desensitization, and recent findings regarding the manner in which β2ARs and cAMP signal, have raised new and interesting questions about these well-studied molecules. In this review we discuss current concepts regarding β2ARs and cAMP in the regulation of ASM cell functions and their therapeutic roles in asthma and COPD. PMID:22634112

cAMP regulation of airway smooth muscle function.

PubMed

Billington, Charlotte K; Ojo, Oluwaseun O; Penn, Raymond B; Ito, Satoru

2013-02-01

Agonists activating β(2)-adrenoceptors (β(2)ARs) on airway smooth muscle (ASM) are the drug of choice for rescue from acute bronchoconstriction in patients with both asthma and chronic obstructive pulmonary disease (COPD). Moreover, the use of long-acting β-agonists combined with inhaled corticosteroids constitutes an important maintenance therapy for these diseases. β-Agonists are effective bronchodilators due primarily to their ability to antagonize ASM contraction. The presumed cellular mechanism of action involves the generation of intracellular cAMP, which in turn can activate the effector molecules cAMP-dependent protein kinase (PKA) and Epac. Other agents such as prostaglandin E(2) and phosphodiesterase inhibitors that also increase intracellular cAMP levels in ASM, can also antagonize ASM contraction, and inhibit other ASM functions including proliferation and migration. Therefore, β(2)ARs and cAMP are key players in combating the pathophysiology of airway narrowing and remodeling. However, limitations of β-agonist therapy due to drug tachyphylaxis related to β(2)AR desensitization, and recent findings regarding the manner in which β(2)ARs and cAMP signal, have raised new and interesting questions about these well-studied molecules. In this review we discuss current concepts regarding β(2)ARs and cAMP in the regulation of ASM cell functions and their therapeutic roles in asthma and COPD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applications of AMPS-1D for solar cell simulation

NASA Astrophysics Data System (ADS)

Zhu, Hong; Kalkan, Ali Kaan; Hou, Jingya; Fonash, Stephen J.

1999-03-01

The AMPS-1D PC computer program is now used by over 70 groups world-wide for detector and solar cell analysis. It has proved to be a very powerful tool in understanding device operation and physics for single crystal, poly-crystalline and amorphous structures. For example, AMPS-1D has been successful in explaining the "red kink" [1] and the "transient effect" in CdS/CIGS poly-crystalline solar cells. It has been used to show that thin film poly-Si structures, with reasonable light trapping, are capable of competitive solar cell conversion efficiencies. In the case of a-Si:H structures, it has been used, for example, to settle the discrepancies in bandgap measurement, to predict the effective QE>1 phenomenon later seen in these materials [2], to determine the relative roles of interface and bulk properties, and to point the direction toward 16% triple junction structures. In general AMPS-1D is used for cell and detector design, material parameter sensitivity studies, and parameter extraction. Recently we have shown that it can be used to determine optimum structure and light and voltage biasing conditions in the material parameter extraction function. Information on AMPS can be found at www.psu.edu/dept/AMPS/amps_web/AMPS.html and at other web sites set up by user groups.

Mechanism of cAMP Partial Agonism in Protein Kinase G (PKG)*♦

PubMed Central

VanSchouwen, Bryan; Selvaratnam, Rajeevan; Giri, Rajanish; Lorenz, Robin; Herberg, Friedrich W.; Kim, Choel; Melacini, Giuseppe

2015-01-01

Protein kinase G (PKG) is a major receptor of cGMP and controls signaling pathways often distinct from those regulated by cAMP. Hence, the selective activation of PKG by cGMP versus cAMP is critical. However, the mechanism of cGMP-versus-cAMP selectivity is only limitedly understood. Although the C-terminal cyclic nucleotide-binding domain B of PKG binds cGMP with higher affinity than cAMP, the intracellular concentrations of cAMP are typically higher than those of cGMP, suggesting that the cGMP-versus-cAMP selectivity of PKG is not controlled uniquely through affinities. Here, we show that cAMP is a partial agonist for PKG, and we elucidate the mechanism for cAMP partial agonism through the comparative NMR analysis of the apo, cGMP-, and cAMP-bound forms of the PKG cyclic nucleotide-binding domain B. We show that although cGMP activation is adequately explained by a two-state conformational selection model, the partial agonism of cAMP arises from the sampling of a third, partially autoinhibited state. PMID:26370085

SPROC: A multiple-processor DSP IC

NASA Technical Reports Server (NTRS)

Davis, R.

1991-01-01

A large, single-chip, multiple-processor, digital signal processing (DSP) integrated circuit (IC) fabricated in HP-Cmos34 is presented. The innovative architecture is best suited for analog and real-time systems characterized by both parallel signal data flows and concurrent logic processing. The IC is supported by a powerful development system that transforms graphical signal flow graphs into production-ready systems in minutes. Automatic compiler partitioning of tasks among four on-chip processors gives the IC the signal processing power of several conventional DSP chips.

SEM probe of IC radiation sensitivity

NASA Technical Reports Server (NTRS)

Gauthier, M. K.; Stanley, A. G.

1979-01-01

Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

Antimicrobial peptides (AMP) with antiviral activity against fish nodavirus.

PubMed

Chia, Ta-Jui; Wu, Yu-Chi; Chen, Jyh-Yih; Chi, Shau-Chi

2010-03-01

Nervous necrosis virus (NNV) is classified as betanodavirus of Nodaviridae, and has caused mass mortality of numerous marine fish species at larval stage. Antimicrobial peptides (AMPs) play an important role of innate immunity either against bacterial pathogens or viruses. Up to date, little is known if any AMP could effectively inhibit fish nodaviruses and its mechanism. In this study, the antiviral activities of three antimicrobial peptides (AMPs) against grouper NNV (GNNV) were screened in the fish cell line. Two of the three AMPs, tilapia hepcidin 1-5 (TH 1-5) and cyclic shrimp anti-lipopolysaccharide factor (cSALF), were able to agglutinate purified NNV particles into clump, and the clumps were further confirmed to be viral proteins by TEM and Western blot. The NNV solution, separately pre-mixed with AMP (TH 1-5 or cSALF) or deionized-distilled water for 1 h, was used to infect GF-1 cells, and the levels of capsid protein in the GNNV-AMP-infected cells at 1 h post infection were much lower than that in the GNNV-H(2)O-infected cells, indicating that only a small portion of viral particles in the GNNV-AMP mixture could successfully infected the cells. Treatment of cBB cells with TH 1-5 and cSALF did not induce Mx gene expression; however, grouper epinecidin-1 (CP643-1) could induce the expression of Mx in the pre-treated cBB cells. This study revealed three AMPs with anti-NNV activity through two different mechanisms, and shed light on the future application in aquaculture. Copyright 2009 Elsevier Ltd. All rights reserved.

AMPS/PC - AUTOMATIC MANUFACTURING PROGRAMMING SYSTEM

NASA Technical Reports Server (NTRS)

Schroer, B. J.

1994-01-01

The AMPS/PC system is a simulation tool designed to aid the user in defining the specifications of a manufacturing environment and then automatically writing code for the target simulation language, GPSS/PC. The domain of problems that AMPS/PC can simulate are manufacturing assembly lines with subassembly lines and manufacturing cells. The user defines the problem domain by responding to the questions from the interface program. Based on the responses, the interface program creates an internal problem specification file. This file includes the manufacturing process network flow and the attributes for all stations, cells, and stock points. AMPS then uses the problem specification file as input for the automatic code generator program to produce a simulation program in the target language GPSS. The output of the generator program is the source code of the corresponding GPSS/PC simulation program. The system runs entirely on an IBM PC running PC DOS Version 2.0 or higher and is written in Turbo Pascal Version 4 requiring 640K memory and one 360K disk drive. To execute the GPSS program, the PC must have resident the GPSS/PC System Version 2.0 from Minuteman Software. The AMPS/PC program was developed in 1988.

Calcium-dependent mitochondrial cAMP production enhances aldosterone secretion.

PubMed

Katona, Dávid; Rajki, Anikó; Di Benedetto, Giulietta; Pozzan, Tullio; Spät, András

2015-09-05

Glomerulosa cells secrete aldosterone in response to agonists coupled to Ca(2+) increases such as angiotensin II and corticotrophin, coupled to a cAMP dependent pathway. A recently recognized interaction between Ca(2+) and cAMP is the Ca(2+)-induced cAMP formation in the mitochondrial matrix. Here we describe that soluble adenylyl cyclase (sAC) is expressed in H295R adrenocortical cells. Mitochondrial cAMP formation, monitored with a mitochondria-targeted fluorescent sensor (4mtH30), is enhanced by HCO3(-) and the Ca(2+) mobilizing agonist angiotensin II. The effect of angiotensin II is inhibited by 2-OHE, an inhibitor of sAC, and by RNA interference of sAC, but enhanced by an inhibitor of phosphodiesterase PDE2A. Heterologous expression of the Ca(2+) binding protein S100G within the mitochondrial matrix attenuates angiotensin II-induced mitochondrial cAMP formation. Inhibition and knockdown of sAC significantly reduce angiotensin II-induced aldosterone production. These data provide the first evidence for a cell-specific functional role of mitochondrial cAMP. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Alternative Fuels Data Center: ampCNG Puts Conventional Fuels Out to

Science.gov Websites

; Steve Josephs, co-founder and director of engineering at ampCNG, Chicago, Illinois When ampCNG isn't the process. ampCNG's Cow-Powered Trucks ampCNG, a CNG station developer based in Chicago, Illinois interest in using more sustainable forms of fuel began in 2010, when the company partnered with Fair Oaks

Application of Boiler Op for combustion optimization at PEPCO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maines, P.; Williams, S.; Levy, E.

1997-09-01

Title IV requires the reduction of NOx at all stations within the PEPCO system. To assist PEPCO plant personnel in achieving low heat rates while meeting NOx targets, Lehigh University`s Energy Research Center and PEPCO developed a new combustion optimization software package called Boiler Op. The Boiler Op code contains an expert system, neural networks and an optimization algorithm. The expert system guides the plant engineer through a series of parametric boiler tests, required for the development of a comprehensive boiler database. The data are then analyzed by the neural networks and optimization algorithm to provide results on the boilermore » control settings which result in the best possible heat rate at a target NOx level or produce minimum NOx. Boiler Op has been used at both Potomac River and Morgantown Stations to help PEPCO engineers optimize combustion. With the use of Boiler Op, Morgantown Station operates under low NOx restrictions and continues to achieve record heat rate values, similar to pre-retrofit conditions. Potomac River Station achieves the regulatory NOx limit through the use of Boiler Op recommended control settings and without NOx burners. Importantly, any software like Boiler Op cannot be used alone. Its application must be in concert with human intelligence to ensure unit safety, reliability and accurate data collection.« less

Receptors for VIP and PACAP in guinea pig cerebral cortex: effects on cyclic AMP synthesis and characterization by 125I-VIP binding.

PubMed

Zawilska, Jolanta B; Dejda, Agnieszka; Niewiadomski, Pawel; Gozes, Illana; Nowak, Jerzy Z

2005-01-01

Receptors for vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) in guinea pig cerebral cortex were characterized by (1) radioreceptor binding of 125I-labeled VIP (human/rat/porcine), and (2) cyclic AMP (cAMP) formation. Saturation analysis of 125I-VIP binding to membranes of guinea pig cerebral cortex resulted in a linear Scatchard plot, suggesting the presence of a single class of high-affinity receptor-binding sites, with a Kd of 0.63 nM and a B(max) of 77 fmol/mg protein. Various peptides from the PACAP/VIP/secretin family displaced the specific binding of 125I-VIP to guinea pig cerebrum with the relative rank order of potency: chicken VIP (cVIP) > or = PACAP38 approximately PACAP27 approximately guinea pig VIP (gpVIP) > or = mammalian (human/rat/porcine) VIP (mVIP) > peptide histidine-methionine (PHM) > peptide histidine-isoleucine (PHI) > secretin. Analysis of the competition curves revealed displacement of 125I-VIP from high- and lower-affinity binding sites, with IC50 values in the picomolar and the nanomolar range, respectively. About 70% of the specific 125I-VIP-binding sites in guinea pig cerebral cortex were sensitive to Gpp(NH)p, a nonhydrolyzable analog of GTP. Pituitary adenylate cyclase-activating polypeptide 38 (PACAP38), PACAP27, cVIP, gpVIP, mVIP, PHM, and PHI stimulated cAMP production in [3H]adenine-prelabeled slices of guinea pig cerebral cortex in a concentration-dependent manner. Of the tested peptides, the most effective were PACAP38 and PACAP27, which at a 1 microM concentration produced a 17- to 19-fold rise in cAMP synthesis, increasing the nucleotide production to approx 11% conversion above the control value. The three forms of VIP (cVIP, mVIP, and gpVIP) at the highest concentration used, i.e., 3 microM, produced net increases in cAMP production in the range of 8-9% conversion, whereas 5 microM PHM and PHI, by, respectively, 6.7% and 4.9% conversion. It is concluded that cerebral cortex

Present, future of automotive hybrid IC applications discussed

NASA Astrophysics Data System (ADS)

Matsuda, Nobuyoshi; Fukuoka, Atuhisa

1987-09-01

Hybrid ICs are presently utilized in various fields such as commercial televisions, VTRs, and audio devices, industrial usage of communication equipment, computers, terminals, and automobiles. Its applications and environments are various and diverse. The functions required for hybrid ICs vary from simple high density mounting for a system to the realization of high mechanisms with the application of function timing. The functions are properly used depending upon the system with its hybrid ICs and its circuit composition. Considering structure and reliability requirements for automotive hybrid ICs, an application example for hybrid ICs which use the package (COMPACT), will be discussed.

The Cognitive Orientation to daily Occupational Performance (CO-OP): A scoping review: L'approche CO-OP (Cognitive Orientation to daily Occupational Performance) : examen de la portée.

PubMed

Scammell, Emma M; Bates, Stephanie V; Houldin, Adina; Polatajko, Helene J

2016-10-01

The Cognitive Orientation to daily Occupational Performance (CO-OP) approach-now trademarked as the CO-OPApproach-was introduced in the literature in 2001 as an intervention to improve real-world performance in children with developmental coordination disorder. CO-OP has since appeared in numerous publications and has seen adoption with various populations. No compilation of the CO-OP literature is available. The purpose of this scoping review was to examine the extent (number) and nature (features and characteristics) of the literature on CO-OP. Using the scoping review methodology outlined by Arksey and O'Malley, 10 online databases were searched for materials discussing CO-OP. Materials found were reviewed by two reviewers, independently. Articles were categorized according to identified study characteristics. In all, 94 documents were found, including 27 research articles examining application and adaptations of CO-OP with eight populations. In all cases, the approach was deemed useful; however, in many cases, adaptations to the CO-OP protocol were recommended. CO-OP has been applied with a number of populations. There is now sufficient research to warrant a systematic review of the research literature. © CAOT 2016.

The Magnetics Information Consortium (MagIC)

NASA Astrophysics Data System (ADS)

Johnson, C.; Constable, C.; Tauxe, L.; Koppers, A.; Banerjee, S.; Jackson, M.; Solheid, P.

2003-12-01

The Magnetics Information Consortium (MagIC) is a multi-user facility to establish and maintain a state-of-the-art relational database and digital archive for rock and paleomagnetic data. The goal of MagIC is to make such data generally available and to provide an information technology infrastructure for these and other research-oriented databases run by the international community. As its name implies, MagIC will not be restricted to paleomagnetic or rock magnetic data only, although MagIC will focus on these kinds of information during its setup phase. MagIC will be hosted under EarthRef.org at http://earthref.org/MAGIC/ where two "integrated" web portals will be developed, one for paleomagnetism (currently functional as a prototype that can be explored via the http://earthref.org/databases/PMAG/ link) and one for rock magnetism. The MagIC database will store all measurements and their derived properties for studies of paleomagnetic directions (inclination, declination) and their intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). Ultimately, this database will allow researchers to study "on the internet" and to download important data sets that display paleo-secular variations in the intensity of the Earth's magnetic field over geological time, or that display magnetic data in typical Zijderveld, hysteresis/FORC and various magnetization/remanence diagrams. The MagIC database is completely integrated in the EarthRef.org relational database structure and thus benefits significantly from already-existing common database components, such as the EarthRef Reference Database (ERR) and Address Book (ERAB). The ERR allows researchers to find complete sets of literature resources as used in GERM (Geochemical Earth Reference Model), REM (Reference Earth Model) and MagIC. The ERAB contains addresses for all contributors to the EarthRef.org databases, and also for those who participated in data collection, archiving and

New generation QuIC assays for prion seeding activity.

PubMed

Orrù, Christina D; Wilham, Jason M; Vascellari, Sarah; Hughson, Andrew G; Caughey, Byron

2012-01-01

The ability of abnormal TSE-associated forms of PrP to seed the formation of amyloid fibrils from recombinant PrP(Sen) has served as the basis for several relatively rapid and highly sensitive tests for prion diseases. These tests include rPrP-PMCA (rPMCA), standard quaking-induced conversion (S-QuIC), amyloid seeding assay (ASA), real-time QuIC (RT-QuIC) and enhanced QuIC (eQuIC). Here, we summarize recent improvements in the RT-QuIC-based assays that enhance the practicality, sensitivity and quantitative attributes of assays QuIC and promote the detection of prion seeding activity in dilute, inhibitor-laden fluids such as blood plasma.

10 CFR Appendixes O-P to Part 50 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false [Reserved] O Appendixes O-P to Part 50 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Appendixes O-P to Part 50 [Reserved] ...

10 CFR Appendixes O-P to Part 50 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false [Reserved] O Appendixes O-P to Part 50 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Appendixes O-P to Part 50 [Reserved] ...

10 CFR Appendixes O-P to Part 50 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false [Reserved] O Appendixes O-P to Part 50 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Appendixes O-P to Part 50 [Reserved] ...

10 CFR Appendixes O-P to Part 50 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false [Reserved] O Appendixes O-P to Part 50 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Appendixes O-P to Part 50 [Reserved] ...

Hamiltonian structure of real Monge - Ampère equations

NASA Astrophysics Data System (ADS)

Nutku, Y.

1996-06-01

The variational principle for the real homogeneous Monge - Ampère equation in two dimensions is shown to contain three arbitrary functions of four variables. There exist two different specializations of this variational principle where the Lagrangian is degenerate and furthermore contains an arbitrary function of two variables. The Hamiltonian formulation of these degenerate Lagrangian systems requires the use of Dirac's theory of constraints. As in the case of most completely integrable systems the constraints are second class and Dirac brackets directly yield the Hamiltonian operators. Thus the real homogeneous Monge - Ampère equation in two dimensions admits two classes of infinitely many Hamiltonian operators, namely a family of local, as well as another family non-local Hamiltonian operators and symplectic 2-forms which depend on arbitrary functions of two variables. The simplest non-local Hamiltonian operator corresponds to the Kac - Moody algebra of vector fields and functions on the unit circle. Hamiltonian operators that belong to either class are compatible with each other but between classes there is only one compatible pair. In the case of real Monge - Ampère equations with constant right-hand side this compatible pair is the only pair of Hamiltonian operators that survives. Then the complete integrability of all these real Monge - Ampère equations follows by Magri's theorem. Some of the remarkable properties we have obtained for the Hamiltonian structure of the real homogeneous Monge - Ampère equation in two dimensions turn out to be generic to the real homogeneous Monge - Ampère equation and the geodesic flow for the complex homogeneous Monge - Ampère equation in arbitrary number of dimensions. Hence among all integrable nonlinear evolution equations in one space and one time dimension, the real homogeneous Monge - Ampère equation is distinguished as one that retains its character as an integrable system in multiple dimensions.

AMP-guided tumour-specific nanoparticle delivery via adenosine A1 receptor.

PubMed

Dai, Tongcheng; Li, Na; Han, Fajun; Zhang, Hua; Zhang, Yuanxing; Liu, Qin

2016-03-01

Active targeting-ligands have been increasingly used to functionalize nanoparticles for tumour-specific clinical applications. Here we utilize nucleotide adenosine 5'-monophosphate (AMP) as a novel ligand to functionalize polymer-based fluorescent nanoparticles (NPs) for tumour-targeted imaging. We demonstrate that AMP-conjugated NPs (NPs-AMP) efficiently bind to and are following internalized into colon cancer cell CW-2 and breast cancer cell MDA-MB-468 in vitro. RNA interference and inhibitor assays reveal that the targeting effects mainly rely on the specific binding of AMP to adenosine A1 receptor (A1R), which is greatly up-regulated in cancer cells than in matched normal cells. More importantly, NPs-AMP specifically accumulate in the tumour site of colon and breast tumour xenografts and are further internalized into the tumour cells in vivo via tail vein injection, confirming that the high in vitro specificity of AMP can be successfully translated into the in vivo efficacy. Furthermore, NPs-AMP exhibit an active tumour-targeting behaviour in various colon and breast cancer cells, which is positively related to the up-regulation level of A1R in cancer cells, suggesting that AMP potentially suits for more extensive A1R-overexpressing cancer models. This work establishes AMP to be a novel tumour-targeting ligand and provides a promising strategy for future diagnostic or therapeutic applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

AmpC β-lactamases in nosocomial isolates of Klebsiella pneumoniae from India

PubMed Central

Gupta, Varsha; Kumarasamy, Karthikeyan; Gulati, Neelam; Garg, Ritu; Krishnan, Padma; Chander, Jagdish

2012-01-01

Background & objectives: AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. Methods: One hundred consecutive, non-duplicate clinical isolates of K. pneumoniae collected over a period of one year (June 2008 - June 2009) were included in the study. An antibiotic susceptibility method was used with 10 antibiotics for Gram-negative infections which helped in screening for ESBL and AmpC β-lactamases and also in confirmation of ESBL production. The detection of AmpC β-lactamases was done based on screening and confirmatory tests. For screening, disc diffusion zones of cefoxitin <18 mm was taken as cefoxitin resistant. All cefoxitin resistant isolates were tested further by AmpC disk test and modified three dimensional test. Multiplex-PCR was performed for screening the presence of plasmid-mediated AmpC genes. Results: Of the 100 isolates of K. pneumoniae studied, 48 were resistant to cefoxitin on screening. AmpC disk test was positive in 32 (32%) isolates. This was also confirmed with modified three dimensional test. Indentation indicating strong AmpC producer was observed in 25 isolates whereas little distortion (weak AmpC) was observed in 7 isolates. ESBL detection was confirmed by a modification of double disk synergy test in 56 isolates. Cefepime was the best cephalosporin in synergy with tazobactam for detecting ESBL production in isolates co-producing AmpC β-lactamases. The subsets of isolates phenotypically AmpC β-lactamase positive were subjected to amplification of six different families of AmpC gene using multiplex PCR. The sequence analysis revealed 12 CMY-2 and eight DHA-1 types. Interpretation & conclusions: Tazobactam was the best β-lactamase inhibitor for detecting

Dynamical Competition of IC-Industry Clustering from Taiwan to China

NASA Astrophysics Data System (ADS)

Tsai, Bi-Huei; Tsai, Kuo-Hui

2009-08-01

Most studies employ qualitative approach to explore the industrial clusters; however, few research has objectively quantified the evolutions of industry clustering. The purpose of this paper is to quantitatively analyze clustering among IC design, IC manufacturing as well as IC packaging and testing industries by using the foreign direct investment (FDI) data. The Lotka-Volterra system equations are first adopted here to capture the competition or cooperation among such three industries, thus explaining their clustering inclinations. The results indicate that the evolution of FDI into China for IC design industry significantly inspire the subsequent FDI of IC manufacturing as well as IC packaging and testing industries. Since IC design industry lie in the upstream stage of IC production, the middle-stream IC manufacturing and downstream IC packing and testing enterprises tend to cluster together with IC design firms, in order to sustain a steady business. Finally, Taiwan IC industry's FDI amount into China is predicted to cumulatively increase, which supports the industrial clustering tendency for Taiwan IC industry. Particularly, the FDI prediction of Lotka-Volterra model performs superior to that of the conventional Bass model after the forecast accuracy of these two models are compared. The prediction ability is dramatically improved as the industrial mutualism among each IC production stage is taken into account.

The glutamate carboxypeptidase AMP1 mediates abscisic acid and abiotic stress responses in Arabidopsis.

PubMed

Shi, Yiting; Wang, Zheng; Meng, Pei; Tian, Siqi; Zhang, Xiaoyan; Yang, Shuhua

2013-07-01

ALTERED MERISTEM PROGRAM1 (AMP1) encodes a glutamate carboxypeptidase that plays an important role in shoot apical meristem development and phytohormone homeostasis. We isolated a new mutant allele of AMP1, amp1-20, from a screen for abscisic acid (ABA) hypersensitive mutants and characterized the function of AMP1 in plant stress responses. amp1 mutants displayed ABA hypersensitivity, while overexpression of AMP1 caused ABA insensitivity. Moreover, endogenous ABA concentration was increased in amp1-20- and decreased in AMP1-overexpressing plants under stress conditions. Application of ABA reduced the AMP1 protein level in plants. Interestingly, amp1 mutants accumulated excess superoxide and displayed hypersensitivity to oxidative stress. The hypersensitivity of amp1 to ABA and oxidative stress was partially rescued by reactive oxygen species (ROS) scavenging agent. Furthermore, amp1 was tolerant to freezing and drought stress. The ABA hypersensitivity and freezing tolerance of amp1 was dependent on ABA signaling. Moreover, amp1 had elevated soluble sugar content and showed hypersensitivity to high concentrations of sugar. By contrast, the contents of amino acids were changed in amp1 mutant compared to the wild-type. This study suggests that AMP1 modulates ABA, oxidative and abotic stress responses, and is involved in carbon and amino acid metabolism in Arabidopsis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Anticonvulsant effect of AMP by direct activation of adenosine A1 receptor.

PubMed

Muzzi, Mirko; Coppi, Elisabetta; Pugliese, Anna Maria; Chiarugi, Alberto

2013-12-01

Purinergic neurotransmission mediated by adenosine (Ado) type 1 receptors (A1Rs) plays pivotal roles in negative modulation of epileptic seizures, and Ado is thought to be a key endogenous anticonvulsant. Recent evidence, however, indicates that AMP, the metabolic precursor of Ado, also activate A1Rs. Here, we evaluated the antiepileptic effects of AMP adopting in vitro and in vivo models of epilepsy. We report that AMP reversed the increase in population spike (PS) amplitude and the decrease in PS latency induced by a Mg(2+)-free extracellular solution in CA1 neurons of mouse hippocampal slices. The AMP effects were inhibited by the A1R antagonist DPCPX, but not prevented by inhibiting conversion of AMP into Ado, indicating that AMP inhibited per se sustained hippocampal excitatory neurotransmission by directly activating A1Rs. AMP also reduced seizure severity and mortality in a model of audiogenic convulsion. Of note, the anticonvulsant effects of AMP were potentiated by preventing its conversion into Ado and inhibited by DPCPX. When tested in a model of kainate-induced seizure, AMP prolonged latency of convulsions but had no effects on seizure severity and mortality. Data provide the first evidence that AMP is an endogenous anticonvulsant acting at A1Rs. © 2013.

Activation of AMP-kinase by Policosanol Requires Peroxisomal Metabolism

PubMed Central

Banerjee, Subhashis; Ghoshal, Sarbani

2011-01-01

Policosanol, a well-defined mixture of very long chain primary alcohols that is available as a nutraceutical product, has been reported to lower blood cholesterol levels. The present studies demonstrate that policosanol promotes the phosphorylation of AMP-kinase and HMG-CoA reductase in hepatoma cells and in mouse liver after intragastric administration, providing a possible means by which policosanol might lower blood cholesterol levels. Treatment of hepatoma cells with policosanol produced a 2.5-fold or greater increase in the phosphorylation of AMP-kinase and HMG-CoA reductase, and increased the phosphorylation of Ca++/calmodulin-dependent kinase kinase (CaMKK), an upstream AMP-kinase kinase. Intra-gastric administration of policosanol to mice similarly increased the phosphorylation of hepatic HMG-CoA reductase and AMP-kinase by greater than 2-fold. siRNA-mediated suppression of fatty aldehyde dehydrogenase, fatty acyl-CoA synthetase 4, and acyl-CoA acetyltransferase expression in hepatoma cells prevented the phosphorylation of AMP-kinase and HMG-CoA reductase by policosanol, indicating that metabolism of these very long chain alcohols to activated fatty acids is necessary for the suppression of cholesterol synthesis, presumably by increasing cellular AMP levels. Subsequent peroxisomal β-oxidation probably augments this effect. PMID:21359855

AmpH, a bifunctional DD-endopeptidase and DD-carboxypeptidase of Escherichia coli.

PubMed

González-Leiza, Silvia M; de Pedro, Miguel A; Ayala, Juan A

2011-12-01

In Escherichia coli, low-molecular-mass penicillin-binding proteins (LMM PBPs) are important for correct cell morphogenesis. These enzymes display DD-carboxypeptidase and/or dd-endopeptidase activities associated with maturation and remodeling of peptidoglycan (PG). AmpH has been classified as an AmpH-type class C LMM PBP, a group closely related to AmpC β-lactamases. AmpH has been associated with PG recycling, although its enzymatic activity remained uncharacterized until now. Construction and purification of His-tagged AmpH from E. coli permitted a detailed study of its enzymatic properties. The N-terminal export signal of AmpH is processed, but the protein remains membrane associated. The PBP nature of AmpH was demonstrated by its ability to bind the β-lactams Bocillin FL (a fluorescent penicillin) and cefmetazole. In vitro assays with AmpH and specific muropeptides demonstrated that AmpH is a bifunctional DD-endopeptidase and DD-carboxypeptidase. Indeed, the enzyme cleaved the cross-linked dimers tetrapentapeptide (D45) and tetratetrapeptide (D44) with efficiencies (k(cat)/K(m)) of 1,200 M(-1) s(-1) and 670 M(-1) s(-1), respectively, and removed the terminal D-alanine from muropeptides with a C-terminal D-Ala-D-Ala dipeptide. Both DD-peptidase activities were inhibited by 40 μM cefmetazole. AmpH also displayed a weak β-lactamase activity for nitrocefin of 1.4 × 10(-3) nmol/μg protein/min, 1/1,000 the rate obtained for AmpC under the same conditions. AmpH was also active on purified sacculi, exhibiting the bifunctional character that was seen with pure muropeptides. The wide substrate spectrum of the DD-peptidase activities associated with AmpH supports a role for this protein in PG remodeling or recycling.

AmpH, a Bifunctional dd-Endopeptidase and dd-Carboxypeptidase of Escherichia coli▿

PubMed Central

González-Leiza, Silvia M.; de Pedro, Miguel A.; Ayala, Juan A.

2011-01-01

In Escherichia coli, low-molecular-mass penicillin-binding proteins (LMM PBPs) are important for correct cell morphogenesis. These enzymes display dd-carboxypeptidase and/or dd-endopeptidase activities associated with maturation and remodeling of peptidoglycan (PG). AmpH has been classified as an AmpH-type class C LMM PBP, a group closely related to AmpC β-lactamases. AmpH has been associated with PG recycling, although its enzymatic activity remained uncharacterized until now. Construction and purification of His-tagged AmpH from E. coli permitted a detailed study of its enzymatic properties. The N-terminal export signal of AmpH is processed, but the protein remains membrane associated. The PBP nature of AmpH was demonstrated by its ability to bind the β-lactams Bocillin FL (a fluorescent penicillin) and cefmetazole. In vitro assays with AmpH and specific muropeptides demonstrated that AmpH is a bifunctional dd–endopeptidase and dd-carboxypeptidase. Indeed, the enzyme cleaved the cross-linked dimers tetrapentapeptide (D45) and tetratetrapeptide (D44) with efficiencies (kcat/Km) of 1,200 M−1 s−1 and 670 M−1 s−1, respectively, and removed the terminal d-alanine from muropeptides with a C-terminal d-Ala-d-Ala dipeptide. Both dd-peptidase activities were inhibited by 40 μM cefmetazole. AmpH also displayed a weak β-lactamase activity for nitrocefin of 1.4 × 10−3 nmol/μg protein/min, 1/1,000 the rate obtained for AmpC under the same conditions. AmpH was also active on purified sacculi, exhibiting the bifunctional character that was seen with pure muropeptides. The wide substrate spectrum of the dd-peptidase activities associated with AmpH supports a role for this protein in PG remodeling or recycling. PMID:22001512

A winged helix forkhead (FOXD2) tunes sensitivity to cAMP in T lymphocytes through regulation of cAMP-dependent protein kinase RIalpha.

PubMed

Johansson, C Christian; Dahle, Maria K; Blomqvist, Sandra Rodrigo; Grønning, Line M; Aandahl, Einar M; Enerbäck, Sven; Taskén, Kjetil

2003-05-09

Forkhead/winged helix (FOX) transcription factors are essential for control of the cell cycle and metabolism. Here, we show that spleens from Mf2-/- (FOXD2-/-) mice have reduced mRNA (50%) and protein (35%) levels of the RIalpha subunit of the cAMP-dependent protein kinase. In T cells from Mf2-/- mice, reduced levels of RIalpha translates functionally into approximately 2-fold less sensitivity to cAMP-mediated inhibition of proliferation triggered through the T cell receptor-CD3 complex. In Jurkat T cells, FOXD2 overexpression increased the endogenous levels of RIalpha through induction of the RIalpha1b promoter. FOXD2 overexpression also increased the sensitivity of the promoter to cAMP. Finally, co-expression experiments demonstrated that protein kinase Balpha/Akt1 work together with FOXD2 to induce the RIalpha1b promoter (10-fold) and increase endogenous RIalpha protein levels further. Taken together, our data indicate that FOXD2 is a physiological regulator of the RIalpha1b promoter in vivo working synergistically with protein kinase B to induce cAMP-dependent protein kinase RIalpha expression, which increases cAMP sensitivity and sets the threshold for cAMP-mediated negative modulation of T cell activation.

Copper Regulates Cyclic AMP-Dependent Lipolysis

PubMed Central

Krishnamoorthy, Lakshmi; Cotruvo, Joseph A.; Chan, Jefferson; Kaluarachchi, Harini; Muchenditsi, Abigael; Pendyala, Venkata S.; Jia, Shang; Aron, Allegra T.; Ackerman, Cheri M.; Vander Wal, Mark N.; Guan, Timothy; Smaga, Lukas P.; Farhi, Samouil L.; New, Elizabeth J.; Lutsenko, Svetlana; Chang, Christopher J.

2016-01-01

Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium, and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining the body's weight and energy stores. Utilizing a murine model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we demonstrate that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue within a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype. PMID:27272565

High performance MPEG-audio decoder IC

NASA Technical Reports Server (NTRS)

Thorn, M.; Benbassat, G.; Cyr, K.; Li, S.; Gill, M.; Kam, D.; Walker, K.; Look, P.; Eldridge, C.; Ng, P.

1993-01-01

The emerging digital audio and video compression technology brings both an opportunity and a new challenge to IC design. The pervasive application of compression technology to consumer electronics will require high volume, low cost IC's and fast time to market of the prototypes and production units. At the same time, the algorithms used in the compression technology result in complex VLSI IC's. The conflicting challenges of algorithm complexity, low cost, and fast time to market have an impact on device architecture and design methodology. The work presented in this paper is about the design of a dedicated, high precision, Motion Picture Expert Group (MPEG) audio decoder.

Real-time monitoring of intracellular cAMP during acute ethanol exposure

PubMed Central

Gupta, Ratna; Qualls-Creekmore, Emily; Yoshimura, Masami

2013-01-01

Background In previous studies we have shown that ethanol enhances the activity of Gs-stimulated membrane-bound adenylyl cyclase (AC). The effect is AC isoform specific and the type 7 AC (AC7) is most responsive to ethanol. In this study, we employed a fluorescence resonance energy transfer (FRET) based cAMP sensor, Epac1-camps, to examine real-time temporal dynamics of ethanol effects on cAMP concentrations. To our knowledge, this is the first report on real-time detection of the ethanol effect on intracellular cAMP. Methods Hela cells were transfected with Epac1-camps, dopamine D1A receptor, and one isoform of AC (AC7 or AC3). Fluorescent images were captured using a specific filter set for cyan fluorescent protein (CFP), yellow fluorescent protein (YFP), and FRET, respectively and FRET intensity was calculated on a pixel-by-pixel basis to examine changes in cAMP. Results During 2-minute stimulation with dopamine (DA), the cytoplasmic cAMP level quickly increased, then decreased to a plateau, where the cAMP level was higher than the level prior to stimulation with DA. Ethanol concentration dependently increased cytoplasmic cAMP in cells transfected with AC7, while ethanol did not have effect on cells transfected with AC3. Similar trends were observed for cAMP at the plasma membrane and in the nucleus during 2-minute stimulation with DA. Unexpectedly, when cells expressing AC7 were stimulated with DA or other Gs protein-coupled receptor’s ligand plus ethanol for 5 seconds, ethanol reduced cAMP concentration. Conclusion These results suggest that ethanol has two opposing effects on the cAMP generating system in an AC isoform specific manner, the enhancing effect on AC activity and the short lived inhibitory effect. Thus, ethanol may have a different effect on cAMP depending on not only AC isoform but also the duration of exposure. PMID:23731206

Using Learning Environments to Create Meaningful Work for Co-Op Students

ERIC Educational Resources Information Center

Nevison, Colleen; Drewery, David; Pretti, Judene; Cormier, Lauren

2017-01-01

For students in cooperative education (co-op) programs, meaningful work is a critical aspect of participation and a key component of program success. However, studies have not explored how meaningful work can be created for co-op students. The purpose of this study was to evaluate the relationship between co-op students' perceptions of a learning…

Mechanism for iron control of the Vibrio fischeri luminescence system: involvement of cyclic AMP and cyclic AMP receptor protein and modulation of DNA level.

PubMed

Dunlap, P V

1992-07-01

Iron controls luminescence in Vibrio fischeri by an indirect but undefined mechanism. To gain insight into that mechanism, the involvement of cyclic AMP (cAMP) and cAMP receptor protein (CRP) and of modulation of DNA levels in iron control of luminescence were examined in V. fischeri and in Escherichia coli containing the cloned V. fischeri lux genes on plasmids. For V. fischeri and E. coli adenylate cyclase (cya) and CRP (crp) mutants containing intact lux genes (luxR luxICDABEG), presence of the iron chelator ethylenediamine-di(o-hydroxyphenyl acetic acid) (EDDHA) increased expression of the luminescence system like in the parent strains only in the cya mutants in the presence of added cAMP. In the E. coli strains containing a plasmid with a Mu dl(lacZ) fusion in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the lux operon promoter) were both 2-3-fold higher in the presence of EDDHA in the parent strain, and for the mutants this response to EDDHA was observed only in the cya mutant in the presence of added cAMP. Therefore, cAMP and CRP are required for the iron restriction effect on luminescence, and their involvement in iron control apparently is distinct from the known differential control of transcription from the luxR and luxICDABEG promoters by cAMP-CRP. Furthermore, plasmid and chromosomal DNA levels were higher in E. coli and V. fischeri in the presence of EDDHA. The higher DNA levels correlated with an increase in expression of chromosomally encoded beta-galactosidase in E. coli and with a higher level of autoinducer in cultures of V. fischeri. These results implicate cAMP-CRP and modulation of DNA levels in the mechanism of iron control of the V. fischeri luminescence system.

Extracellular cyclic AMP-adenosine pathway in isolated adipocytes and adipose tissue.

PubMed

Strouch, Marci B; Jackson, Edwin K; Mi, Zaichuan; Metes, Nicole A; Carey, Gale B

2005-06-01

Our goal was to evaluate the presence and lipolytic impact of the extracellular cyclic adenosine monophosphate (AMP)-adenosine pathway in adipose tissue. Sixteen miniature Yucatan swine (Sus scrofa) were used for these in vitro and in situ experiments. Four microdialysis probes were implanted into subcutaneous adipose tissue and perfused at 2 microL/min with Ringer's solution containing no addition, varying levels of cyclic AMP, 10 microM isoproterenol, or 10 microM isoproterenol plus 1 mM alpha,beta-methylene adenosine 5'-diphosphate (AMPCP), a 5'-nucleotidase inhibitor. Dialysate was assayed for AMP, adenosine, inosine, hypoxanthine, and glycerol. Freshly isolated adipocytes were incubated with buffer, 1 microM isoproterenol, or 1 microM isoproterenol plus 0.1 mM AMPCP, and extracellular levels of AMP, adenosine, inosine, hypoxanthine, and glycerol were measured. Perfusion of adipose tissue with exogenous cyclic AMP caused a significant increase in AMP and adenosine appearance. Perfusion with AMPCP, in the presence or absence of isoproterenol, significantly increased the levels of AMP and glycerol, whereas it significantly reduced the level of adenosine and its metabolites. However, the AMPCP-provoked increase in lipolysis observed in situ and in vitro was not temporally associated with a decrease in adenosine. These data suggest the existence of a cyclic AMP-adenosine pathway in adipocytes and adipose tissue. The role of this pathway in the regulation of lipolysis remains to be clarified.

Geometry and Op Art.

ERIC Educational Resources Information Center

Brewer, Evelyn J.

1999-01-01

Describes an activity in which students use computers and techniques from Op Art to learn various geometric concepts. Allows them to see the distinct connection between art and mathematics from a personal perspective. Reinforces writing, speaking, and drawing skills while creating slide shows related to the project. (ASK)

Amp Synthesis in Aqueous Solution of Adenosine and Phosphorus Pentoxide

NASA Astrophysics Data System (ADS)

Yamagata, Y.; Kojima, H.; Ejiri, K.; Inomata, K.

1982-12-01

Possible formation of a P4O10 molecule in magma, the stability of the molecule in hydrous volcanic gas at high temperatures and a possible prebiotic phosphate cycle were discussed in relation to chemical evolution. To demonstrate the utility of phosphorus pentoxide as a phosphorylating agent, aqueous solutions of adenosine (0.02M) and phosphorus pentoxide (0.2M) were incubated at 37°C for 5 months. The pH of the solutions was adjusted every day or every few days to each fixed value (9.0, 10.5, 11.5, 12.5) with 10 N NaOH. The HPLC analysis showed the formation of 2'-AMP, 3'-AMP, 5'-AMP, cyclic (2' 3')-AMP and cyclic (3' 5')-AMP. The main components of the products were 2'- and 3'-AMP, though cyclic (2' 3')-AMP was the main component in the early period of the incubation at pH 9.0. The yields (conversion rate of adenosine to AMPs) were increased almost linearly with the incubation time for 5 months in the case of pH 9.0. The final yields were about 3% (pH 9.0), 6% (pH 9.0, 1 M NaCl), 5% (pH 9.0, 0.01 M CaCl2, 0.01 M MgCl2), 7% (pH 9.0, 0.5 M NaCl, 0.01 M CaCl2, 0.01 M MgCl2), 9% (pH 9.0, 1 M NaCl, 0.01 M CaCl2, 0.01 M MgCl2), 32% (pH 10.5), 43% (pH 11.5), 35% (pH 12.5).

Information Commons for Rice (IC4R)

PubMed Central

2016-01-01

Rice is the most important staple food for a large part of the world's human population and also a key model organism for plant research. Here, we present Information Commons for Rice (IC4R; http://ic4r.org), a rice knowledgebase featuring adoption of an extensible and sustainable architecture that integrates multiple omics data through community-contributed modules. Each module is developed and maintained by different committed groups, deals with data collection, processing and visualization, and delivers data on-demand via web services. In the current version, IC4R incorporates a variety of rice data through multiple committed modules, including genome-wide expression profiles derived entirely from RNA-Seq data, resequencing-based genomic variations obtained from re-sequencing data of thousands of rice varieties, plant homologous genes covering multiple diverse plant species, post-translational modifications, rice-related literatures and gene annotations contributed by the rice research community. Unlike extant related databases, IC4R is designed for scalability and sustainability and thus also features collaborative integration of rice data and low costs for database update and maintenance. Future directions of IC4R include incorporation of other omics data and association of multiple omics data with agronomically important traits, dedicating to build IC4R into a valuable knowledgebase for both basic and translational researches in rice. PMID:26519466

Mycobacterium tuberculosis cAMP Receptor Protein (Rv3676) Differs from the Escherichia coli Paradigm in Its cAMP Binding and DNA Binding Properties and Transcription Activation Properties*

PubMed Central

Stapleton, Melanie; Haq, Ihtshamul; Hunt, Debbie M.; Arnvig, Kristine B.; Artymiuk, Peter J.; Buxton, Roger S.; Green, Jeffrey

2010-01-01

The pathogen Mycobacterium tuberculosis produces a burst of cAMP upon infection of macrophages. Bacterial cyclic AMP receptor proteins (CRP) are transcription factors that respond to cAMP by binding at target promoters when cAMP concentrations increase. Rv3676 (CRPMt) is a CRP family protein that regulates expression of genes (rpfA and whiB1) that are potentially involved in M. tuberculosis persistence and/or emergence from the dormant state. Here, the CRPMt homodimer is shown to bind two molecules of cAMP (one per protomer) at noninteracting sites. Furthermore, cAMP binding by CRPMt was relatively weak, entropy driven, and resulted in a relatively small enhancement in DNA binding. Tandem CRPMt-binding sites (CRP1 at −58.5 and CRP2 at −37.5) were identified at the whiB1 promoter (PwhiB1). In vitro transcription reactions showed that CRP1 is an activating site and that CRP2, which was only occupied in the presence of cAMP or at high CRPMt concentrations in the absence of cAMP, is a repressing site. Binding of CRPMt to CRP1 was not essential for open complex formation but was required for transcription activation. Thus, these data suggest that binding of CRPMt to the PwhiB1 CRP1 site activates transcription at a step after open complex formation. In contrast, high cAMP concentrations allowed occupation of both CRP1 and CRP2 sites, resulting in inhibition of open complex formation. Thus, M. tuberculosis CRP has evolved several distinct characteristics, compared with the Escherichia coli CRP paradigm, to allow it to regulate gene expression against a background of high concentrations of cAMP. PMID:20028978

On Patarin's Attack against the lIC Scheme

NASA Astrophysics Data System (ADS)

Ogura, Naoki; Uchiyama, Shigenori

In 2007, Ding et al. proposed an attractive scheme, which is called the l-Invertible Cycles (lIC) scheme. lIC is one of the most efficient multivariate public-key cryptosystems (MPKC); these schemes would be suitable for using under limited computational resources. In 2008, an efficient attack against lIC using Gröbner basis algorithms was proposed by Fouque et al. However, they only estimated the complexity of their attack based on their experimental results. On the other hand, Patarin had proposed an efficient attack against some multivariate public-key cryptosystems. We call this attack Patarin's attack. The complexity of Patarin's attack can be estimated by finding relations corresponding to each scheme. In this paper, we propose an another practical attack against the lIC encryption/signature scheme. We estimate the complexity of our attack (not experimentally) by adapting Patarin's attack. The attack can be also applied to the lIC- scheme. Moreover, we show some experimental results of a practical attack against the lIC/lIC- schemes. This is the first implementation of both our proposed attack and an attack based on Gröbner basis algorithm for the even case, that is, a parameter l is even.

Negative feedback exerted by cAMP-dependent protein kinase and cAMP phosphodiesterase on subsarcolemmal cAMP signals in intact cardiac myocytes: an in vivo study using adenovirus-mediated expression of CNG channels.

PubMed

Rochais, Francesca; Vandecasteele, Grégoire; Lefebvre, Florence; Lugnier, Claire; Lum, Hazel; Mazet, Jean-Luc; Cooper, Dermot M F; Fischmeister, Rodolphe

2004-12-10

Intracardiac cAMP levels are modulated by hormones and neuromediators with specific effects on contractility and metabolism. To understand how the same second messenger conveys different information, mutants of the rat olfactory cyclic nucleotide-gated (CNG) channel alpha-subunit CNGA2, encoded into adenoviruses, were used to monitor cAMP in adult rat ventricular myocytes. CNGA2 was not found in native myocytes but was strongly expressed in infected cells. In whole cell patch-clamp experiments, the forskolin analogue L-858051 (L-85) elicited a non-selective, Mg2+ -sensitive current observed only in infected cells, which was thus identified as the CNG current (ICNG). The beta-adrenergic agonist isoprenaline (ISO) also activated ICNG, although the maximal efficiency was approximately 5 times lower than with L-85. However, ISO and L-85 exerted a similar maximal increase of the L-type Ca2+ current. The use of a CNGA2 mutant with a higher sensitivity for cAMP indicated that this difference is caused by the activation of a localized fraction of CNG channels by ISO. cAMP-dependent protein kinase (PKA) blockade with H89 or PKI, or phosphodiesterase (PDE) inhibition with IBMX, dramatically potentiated ISO- and L-85-stimulated ICNG. A similar potentiation of beta-adrenergic stimulation occurred when PDE4 was blocked, whereas PDE3 inhibition had a smaller effect (by 2-fold). ISO and L-85 increased total PDE3 and PDE4 activities in cardiomyocytes, although this effect was insensitive to H89. However, in the presence of IBMX, H89 had no effect on ISO stimulation of ICNG. This study demonstrates that subsarcolemmal cAMP levels are dynamically regulated by a negative feedback involving PKA stimulation of subsarcolemmal cAMP-PDE.

Role of CNPase in the Oligodendrocytic Extracellular 2′,3′-cAMP-Adenosine Pathway

PubMed Central

Verrier, Jonathan D.; Jackson, Travis C.; Gillespie, Delbert G.; Janesko-Feldman, Keri; Bansal, Rashmi; Goebbels, Sandra; Nave, Klaus-Armin; Kochanek, Patrick M.; Jackson, Edwin K.

2014-01-01

Extracellular adenosine 3′,5′-cyclic monophosphate (3′,5′-cAMP) is an endogenous source of localized adenosine production in many organs. Recent studies suggest that extracellular 2′,3′-cAMP (positional isomer of 3′,5′-cAMP) is also a source of adenosine, particularly in the brain in vivo post-injury. Moreover, in vitro studies show that both microglia and astrocytes can convert extracellular 2′,3′-cAMP to adenosine. Here we examined the ability of primary mouse oligodendrocytes and neurons to metabolize extracellular 2′,3′-cAMP and their respective adenosine monophosphates (2′-AMP and 3′-AMP). Cells were also isolated from mice deficient in 2′,3′-cyclic nucleotide-3′-phosphodiesterase (CNPase). Oligodendrocytes metabolized 2′,3′-cAMP to 2′-AMP with 10-fold greater efficiency than did neurons (and also more than previously examined microglia and astrocytes); whereas, the production of 3′-AMP was minimal in both oligodendrocytes and neurons. The production of 2′-AMP from 2′,3′-cAMP was reduced by 65% in CNPase -/- versus CNPase +/+ oligodendrocytes. Oligodendrocytes also converted 2′-AMP to adenosine, and this was also attenuated in CNPase -/- oligodendrocytes. Inhibition of classic 3′,5′-cAMP-3′-phosphodiesterases with 3-isobutyl-1-methylxanthine did not block metabolism of 2′,3′-cAMP to 2′-AMP and inhibition of classic ecto-5′-nucleotidase (CD73) with α,β-methylene-adenosine-5′-diphosphate did not attenuate the conversion of 2′-AMP to adenosine. These studies demonstrate that oligodendrocytes express the extracellular 2′,3′-cAMP-adenosine pathway (2′,3′-cAMP → 2′-AMP → adenosine). This pathway is more robustly expressed in oligodendrocytes than in all other CNS cell types because CNPase is the predominant enzyme that metabolizes 2′,3′-cAMP to 2-AMP in CNS cells. By reducing levels of 2′,3′-cAMP (a mitochondrial toxin) and increasing levels of adenosine (a neuroprotectant

Electing a candidate: a speculative history of the bacterial phylum OP10.

PubMed

Dunfield, Peter F; Tamas, Ivica; Lee, Kevin C; Morgan, Xochitl C; McDonald, Ian R; Stott, Matthew B

2012-12-01

In 1998, a cultivation-independent survey of the microbial community in Obsidian Pool, Yellowstone National Park, detected 12 new phyla within the Domain Bacteria. These were dubbed 'candidate divisions' OP1 to OP12. Since that time the OP10 candidate division has been commonly detected in various environments, usually as part of the rare biosphere, but occasionally as a predominant community component. Based on 16S rRNA gene phylogeny, OP10 comprises at least 12 class-level subdivisions. However, despite this broad ecological and evolutionary diversity, all OP10 bacteria have eluded cultivation until recently. In 2011, two reference species of OP10 were taxonomically validated, removing the phylum from its 'candidate' status. Construction of a highly resolved phylogeny based on 29 universally conserved genes verifies its standing as a unique bacterial phylum. In the following paper we summarize what is known and what is suspected about the newest described bacterial phylum, the Armatimonadetes. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Atmosphere, Magnetosphere and Plasmas in Space (AMPS). Spacelab payload definition study. Volume 3, book 2: AMPS equipment to Spacelab ICD

NASA Technical Reports Server (NTRS)

1976-01-01

The interfaces between AMPS Payload No.(TBD) and Spacelab are described. The interfaces specified cover the AMPS physical, electrical, and thermal interfaces that are established to prescribe the standard Spacelab configuration required to perform the mission. If the configuration definition changes due to change of Spacelab equipment model, or serial numbers, then reidentification of the Labcraft payload may be required.

Blockade of beta-adrenoceptors enhances cAMP signal transduction in vivo

NASA Technical Reports Server (NTRS)

Whalen, E. J.; Johnson, A. K.; Lewis, S. J.

1998-01-01

The aim of this study was to determine whether the blockade of beta-adrenoceptors would enhance cAMP-mediated signal transduction processes in vivo. The administration of the membrane permeable cAMP analogue, 8-(4-chlorophenylthiol)-cAMP (8-CPT-cAMP, 10 micromol/kg, i.v.) produced an increase in heart rate (+27 +/- 2%, P < 0.05), a fall in mean arterial blood pressure (-21 +/- 3%, P < 0.05) and falls in hindquarter (-12 +/- 3%, P < 0.05) and mesenteric (-32 +/- 3%, P < 0.05) vascular resistances in pentobarbital-anesthetized rats. The beta-adrenoceptor antagonist, propranolol (1 mg/kg, i.v.) lowered heart rate (-12 +/- 3%, P < 0.05) but did not affect mean arterial blood pressure or vascular resistances. The tachycardia, hypotension and vasodilation produced by 8-CPT-cAMP were exaggerated after administration of propranolol (P < 0.05 for all comparisons). The nitric oxide-donor, sodium nitroprusside (2 microg/kg, i.v.), produced falls in mean arterial blood pressure and vascular resistances of similar magnitude to those produced by 8-CPT-cAMP. These sodium nitroprusside-induced responses were unaffected by propranolol (P < 0.05 for all comparisons). Sodium nitroprusside also produced a minor increase in heart rate (+5 +/- 1%, P < 0.05) which was abolished by propranolol. These findings suggest that 8-CPT-cAMP directly increases heart rate and that blockade of beta-adrenoceptors enhances the potency of cAMP within the heart and vasculature.

Deconvoluting AMP-activated protein kinase (AMPK) adenine nucleotide binding and sensing

PubMed Central

Gu, Xin; Yan, Yan; Novick, Scott J.; Kovach, Amanda; Goswami, Devrishi; Ke, Jiyuan; Tan, M. H. Eileen; Wang, Lili; Li, Xiaodan; de Waal, Parker W.; Webb, Martin R.; Griffin, Patrick R.; Xu, H. Eric

2017-01-01

AMP-activated protein kinase (AMPK) is a central cellular energy sensor that adapts metabolism and growth to the energy state of the cell. AMPK senses the ratio of adenine nucleotides (adenylate energy charge) by competitive binding of AMP, ADP, and ATP to three sites (CBS1, CBS3, and CBS4) in its γ-subunit. Because these three binding sites are functionally interconnected, it remains unclear how nucleotides bind to individual sites, which nucleotides occupy each site under physiological conditions, and how binding to one site affects binding to the other sites. Here, we comprehensively analyze nucleotide binding to wild-type and mutant AMPK protein complexes by quantitative competition assays and by hydrogen-deuterium exchange MS. We also demonstrate that NADPH, in addition to the known AMPK ligand NADH, directly and competitively binds AMPK at the AMP-sensing CBS3 site. Our findings reveal how AMP binding to one site affects the conformation and adenine nucleotide binding at the other two sites and establish CBS3, and not CBS1, as the high affinity exchangeable AMP/ADP/ATP-binding site. We further show that AMP binding at CBS4 increases AMP binding at CBS3 by 2 orders of magnitude and reverses the AMP/ATP preference of CBS3. Together, these results illustrate how the three CBS sites collaborate to enable highly sensitive detection of cellular energy states to maintain the tight ATP homeostastis required for cellular metabolism. PMID:28615457

Op-amp gyrator simulates high Q inductor

NASA Technical Reports Server (NTRS)

Sutherland, W. C.

1977-01-01

Gyrator circuit consisting of dual operational amplifier and four resistors inverts impedance of capacitor to simulate inductor. Synthetic inductor has high Q factor, good stability, wide bandwidth, and easily determined value of inductance that is independent of frequency. It readily lends itself to integrated-circuit applications, including filter networks.

cAMP enhances BMP2-signaling through PKA and MKP1-dependent mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghayor, Chafik; Ehrbar, Martin; Miguel, Blanca San

2009-04-03

Recent studies suggest that the elevation of intracellular cyclic adenosine monophosphate (cAMP) and the activation of the protein kinase A regulate BMP-induced osteogenesis. However, the precise mechanisms underlying the enhancing effect of cAMP on BMP2 signaling were not completely revealed. In this study we investigated the effect of elevated cAMP level and PKA activation on the BMP2-induced osteoblastic differentiation in pluripotent C2C12 cells. Alkaline phosphatase activity and its mRNA were consistently induced by BMP2 treatment. The pretreatment of C2C12 cells with Forskolin, a cAMP generating agent, dbcAMP, an analogue of cAMP, or IBMX (3-isobutyl 1-methyl xanthine), and a nonspecific inhibitormore » of phosphodiesterases elicited further activation of alkaline phosphatase. Furthermore, elevated intracellular cAMP level increased BMP2-induced MKP1. On the other hand, BMP2-induced Erk phosphorylation (p44/p42) and cell proliferation were suppressed in the presence of cAMP. Thus, cAMP might enhance BMP2-induced osteoblastic differentiation by a MKP1-Erk-dependent mechanism.« less

High glucose enhances cAMP level and extracellular signal-regulated kinase phosphorylation in Chinese hamster ovary cell: Usage of Br-cAMP in foreign protein β-galactosidase expression.

PubMed

Lin, Hsiao-Hsien; Lee, Tsung-Yih; Liu, Ting-Wei; Tseng, Ching-Ping

2017-07-01

Glucose is a carbon source for Chinese hamster ovary (CHO) cell growth, while low growth rate is considered to enhance the production of recombinant proteins. The present study reveals that glucose concentrations higher than 1 g/L reduce the growth rate and substantially increase in cAMP (∼300%) at a high glucose concentration (10 g/L). High glucose also enhances the phosphorylation of extracellular signal-regulated kinase (ERK) and p27 kip by Western blot analysis. To determine whether the phosphorylation of ERK is involved in the mechanism, a cyclic-AMP dependent protein kinase A (PKA) inhibitor (H-8) or MEK (MAPKK) inhibitor (PD98059) was added to block ERK phosphorylation. We show that both the high glucose-induced ERK phosphorylation and growth rate return to baseline levels. These results suggest that the cAMP/PKA and MAP signaling pathways are involved in the abovementioned mechanism. Interestingly, the direct addition of 8-bromo-cAMP (Br-cAMP), a membrane-permeable cAMP analog, can mimic the similar effects produced by high glucose. Subsequently Br-cAMP could induce β-galactosidase (β-Gal) recombinant protein expression by 1.6-fold. Furthermore, Br-cAMP can additionally enhance the β-Gal production (from 2.8- to 4.5-fold) when CHO cells were stimulated with glycerol, thymidine, dimethyl sulfoxide, pentanoic acid, or sodium butyrate. Thus, Br-cAMP may be used as an alternative agent in promoting foreign protein expression for CHO cells. Copyright © 2017. Published by Elsevier B.V.

5D imaging approaches reveal the formation of distinct intracellular cAMP spatial gradients

NASA Astrophysics Data System (ADS)

Rich, Thomas C.; Annamdevula, Naga; Trinh, Kenny; Britain, Andrea L.; Mayes, Samuel A.; Griswold, John R.; Deal, Joshua; Hoffman, Chase; West, Savannah; Leavesley, Silas J.

2017-02-01

Cyclic AMP (cAMP) is a ubiquitous second messenger known to differentially regulate many cellular functions. Several lines of evidence suggest that the distribution of cAMP within cells is not uniform. However, to date, no studies have measured the kinetics of 3D cAMP distributions within cells. This is largely due to the low signal-tonoise ratio of FRET-based probes. We previously reported that hyperspectral imaging improves the signal-to-noise ratio of FRET measurements. Here we utilized hyperspectral imaging approaches to measure FRET signals in five dimensions (5D) - three spatial (x, y, z), wavelength (λ), and time (t) - allowing us to visualize cAMP gradients in pulmonary endothelial cells. cAMP levels were measured using a FRET-based sensor (H188) comprised of a cAMP binding domain sandwiched between FRET donor and acceptor - Turquoise and Venus fluorescent proteins. We observed cAMP gradients in response to 0.1 or 1 μM isoproterenol, 0.1 or 1 μM PGE1, or 50 μM forskolin. Forskolin- and isoproterenol-induced cAMP gradients formed from the apical (high cAMP) to basolateral (low cAMP) face of cells. In contrast, PGE1-induced cAMP gradients originated from both the basolateral and apical faces of cells. Data suggest that 2D (x,y) studies of cAMP compartmentalization may lead to erroneous conclusions about the existence of cAMP gradients, and that 3D (x,y,z) studies are required to assess mechanisms of signaling specificity. Results demonstrate that 5D imaging technologies are powerful tools for measuring biochemical processes in discrete subcellular domains.

Recent Advances in the Development of Antimicrobial Peptides (AMPs): Attempts for Sustainable Medicine?

PubMed

Kokel, Anne; Torok, Marianna

2018-01-17

Since the first isolation of antimicrobial peptides (AMPs) they have attracted extensive interest in medicinal chemistry. However, only a few AMP-based drugs are currently available on the market. Despite their effectiveness, biodegradability, and versatile mode of action that is less likely to induce resistance compared to conventional antibiotics, AMPs suffer from major issues that need to be addressed to broaden their use. Notably, AMPs can lack selectivity leading to side effects and cytotoxicity, and also exhibit in vivo instability. Several strategies are being actively considered to overcome the limitations that restrain the success of AMPs. In the current work, recent strategies reported for improving AMPs in the context of drug design and delivery were surveyed, and also their possible impact on patients and the environment was assessed. As a major advantage AMPs possess an easily tunable skeleton offering opportunities to improve their properties. Strategic structural modifications and the beneficial properties of cyclic or branched AMPs in term of stability have been reported. The conjugation of AMPs with nanoparticles has also been explored to increase their in vivo stability. Other techniques such as the coupling of AMPs with specific antibodies aim to increase the selectivity of the potential drug towards the target. These strategies were evaluated for their effect on the environment highlighting green technologies. Although further research is needed taking into account both environmental and human health consequences of novel AMPs several of these compounds are promising drug candidates for use in sustainable medicine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Actions of cAMP on calcium sensitization in human detrusor smooth muscle contraction.

PubMed

Hayashi, Maya; Kajioka, Shunichi; Itsumi, Momoe; Takahashi, Ryosuke; Shahab, Nouval; Ishigami, Takao; Takeda, Masahiro; Masuda, Noriyuki; Yamaguchi, Akito; Naito, Seiji

2016-01-01

To clarify the effect of cAMP on the Ca(2+) -sensitized smooth muscle contraction in human detrusor, as well as the role of novel exchange protein directly activated by cAMP (Epac) in cAMP-mediated relaxation. All experimental protocols to record isometric tension force were performed using α-toxin-permeabilized human detrusor smooth muscle strips. The mechanisms of cAMP-mediated suppression of Ca(2+) sensitization activated by 10 μm carbachol (CCh) and 100 μm GTP were studied using a selective rho kinase (ROK) inhibitor, Y-27632, and a selective protein kinase C (PKC) inhibitor, GF-109203X. The relaxation mechanisms were further probed using a selective protein kinase A (PKA) activator, 6-Bnz-cAMP and a selective Epac activator, 8-pCPT-2'-O-Me-cAMP. We observed that CCh-induced Ca(2+) sensitization was inhibited by cAMP in a concentration-dependent manner. GF-109203X (10 μm) but not Y-27632 (10 μm) significantly enhanced the relaxation effect induced by cAMP (100 μm). 6-Bnz-cAMP (100 μm) predominantly decreased the tension force in comparison with 8-pCPT-2'-O-Me-cAMP (100 μm). We showed that cAMP predominantly inhibited the ROK pathway but not the PKC pathway. The PKA-dependent pathway is dominant, while Epac plays a minor role in human detrusor smooth muscle Ca(2+) sensitization. © 2015 The Authors BJU International © 2015 BJU International Published by John Wiley & Sons Ltd.

Endoscopic retrograde cholangiopancreatography-associated AmpC Escherichia coli outbreak.

PubMed

Wendorf, Kristen A; Kay, Meagan; Baliga, Christopher; Weissman, Scott J; Gluck, Michael; Verma, Punam; D'Angeli, Marisa; Swoveland, Jennifer; Kang, Mi-Gyeong; Eckmann, Kaye; Ross, Andrew S; Duchin, Jeffrey

2015-06-01

We identified an outbreak of AmpC-producing Escherichia coli infections resistant to third-generation cephalosporins and carbapenems (CR) among 7 patients who had undergone endoscopic retrograde cholangiopancreatography at hospital A during November 2012-August 2013. Gene sequencing revealed a shared novel mutation in a bla CMY gene and a distinctive fumC/ fimH typing profile. To determine the extent and epidemiologic characteristics of the outbreak, identify potential sources of transmission, design and implement infection control measures, and determine the association between the CR E. coli and AmpC E. coli circulating at hospital A. We reviewed laboratory, medical, and endoscopy reports, and endoscope reprocessing procedures. We obtained cultures from endoscopes after reprocessing as well as environmental samples and conducted pulsed-field gel electrophoresis and gene sequencing on phenotypic AmpC isolates from patients and endoscopes. Cases were those infected with phenotypic AmpC isolates (both carbapenem-susceptible and CR) and identical bla CMY-2, fumC, and fimH alleles or related pulsed-field gel electrophoresis patterns. Thirty-five of 49 AmpC E. coli tested met the case definition, including all CR isolates. All cases had complicated biliary disease and had undergone at least 1 endoscopic retrograde cholangiopancreatography at hospital A. Mortality at 30 days was 16% for all patients and 56% for CR patients. Two of 8 reprocessed endoscopic retrograde cholangiopancreatography scopes harbored AmpC that matched case isolates by pulsed-field gel electrophoresis. Environmental cultures were negative. No breaches in infection control were identified. Endoscopic reprocessing exceeded manufacturer's recommended cleaning guidelines. Recommended reprocessing guidelines are not sufficient.

Structural basis of DNA folding and recognition in an AMP-DNA aptamer complex: distinct architectures but common recognition motifs for DNA and RNA aptamers complexed to AMP.

PubMed

Lin, C H; Patel, D J

1997-11-01

Structural studies by nuclear magnetic resonance (NMR) of RNA and DNA aptamer complexes identified through in vitro selection and amplification have provided a wealth of information on RNA and DNA tertiary structure and molecular recognition in solution. The RNA and DNA aptamers that target ATP (and AMP) with micromolar affinity exhibit distinct binding site sequences and secondary structures. We report below on the tertiary structure of the AMP-DNA aptamer complex in solution and compare it with the previously reported tertiary structure of the AMP-RNA aptamer complex in solution. The solution structure of the AMP-DNA aptamer complex shows, surprisingly, that two AMP molecules are intercalated at adjacent sites within a rectangular widened minor groove. Complex formation involves adaptive binding where the asymmetric internal bubble of the free DNA aptamer zippers up through formation of a continuous six-base mismatch segment which includes a pair of adjacent three-base platforms. The AMP molecules pair through their Watson-Crick edges with the minor groove edges of guanine residues. These recognition G.A mismatches are flanked by sheared G.A and reversed Hoogsteen G.G mismatch pairs. The AMP-DNA aptamer and AMP-RNA aptamer complexes have distinct tertiary structures and binding stoichiometries. Nevertheless, both complexes have similar structural features and recognition alignments in their binding pockets. Specifically, AMP targets both DNA and RNA aptamers by intercalating between purine bases and through identical G.A mismatch formation. The recognition G.A mismatch stacks with a reversed Hoogsteen G.G mismatch in one direction and with an adenine base in the other direction in both complexes. It is striking that DNA and RNA aptamers selected independently from libraries of 10(14) molecules in each case utilize identical mismatch alignments for molecular recognition with micromolar affinity within binding-site pockets containing common structural elements.

TDR method for determine IC's parameters

NASA Astrophysics Data System (ADS)

Timoshenkov, V.; Rodionov, D.; Khlybov, A.

2016-12-01

Frequency domain simulation is a widely used approach for determine integrated circuits parameters. This approach can be found in most of software tools used in IC industry. Time domain simulation approach shows intensive usage last years due to some advantages. In particular it applicable for analysis of nonlinear and nonstationary systems where frequency domain is inapplicable. Resolution of time domain systems allow see heterogeneities on distance 1mm, determine it parameters and properties. Authors used approach based on detecting reflected signals from heterogeneities - time domain reflectometry (TDR). Field effect transistor technology scaling up to 30-60nm gate length and 10nm gate dielectric, heterojunction bi-polar transistors with 10-30nm base width allows fabricate digital IC's with 20GHz clock frequency and RF-IC's with tens GHz bandwidth. Such devices and operation speed suppose transit signal by use microwave lines. There are local heterogeneities can be found inside of the signal path due to connections between different parts of signal lines (stripe line-RF-connector pin, stripe line - IC package pin). These heterogeneities distort signals that cause bandwidth decrease for RF-devices. Time domain research methods of transmission and reflected signals give the opportunities to determine heterogeneities, it properties, parameters and built up equivalent circuits. Experimental results are provided and show possibility for inductance and capacitance measurement up to 25GHz. Measurements contains result of signal path research on IC and printed circuit board (PCB) used for 12GHz RF chips. Also dielectric constant versus frequency was measured up to 35GHz.

Dynamics of β-adrenergic/cAMP signaling and morphological changes in cultured astrocytes.

PubMed

Vardjan, Nina; Kreft, Marko; Zorec, Robert

2014-04-01

The morphology of astrocytes, likely regulated by cAMP, determines the structural association between astrocytes and the synapse, consequently modulating synaptic function. β-Adrenergic receptors (β-AR), which increase cytosolic cAMP concentration ([cAMP]i ), may affect cell morphology. However, the real-time dynamics of β-AR-mediated cAMP signaling in single live astrocytes and its effect on cell morphology have not been studied. We used the fluorescence resonance energy transfer (FRET)-based cAMP biosensor Epac1-camps to study time-dependent changes in [cAMP]i ; morphological changes in primary rat astrocytes were monitored by real-time confocal microscopy. Stimulation of β-AR by adrenaline, noradrenaline, and isoprenaline, a specific agonist of β-AR, rapidly increased [cAMP]i (∼15 s). The FRET signal response, mediated via β-AR, was faster than in the presence of forskolin (twofold) and dibutyryl-cAMP (>35-fold), which directly activate adenylyl cyclase and Epac1-camps, respectively, likely due to slow entry of these agents into the cytosol. Oscillations in [cAMP]i have not been recorded, indicating that cAMP-dependent processes operate in a slow time domain. Most Epac1-camps expressing astrocytes revealed a morphological change upon β-AR activation and attained a stellate morphology within 1 h. The morphological changes exhibited a bell-shaped dependency on [cAMP]i . The 5-10% decrease in cell cross-sectional area and the 30-50% increase in cell perimeter are likely due to withdrawal of the cytoplasm to the perinuclear region and the appearance of protrusions on the surface of astrocytes. Because astrocyte processes ensheath neurons, β-AR/cAMP-mediated morphological changes can modify the geometry of the extracellular space, affecting synaptic, neuronal, and astrocyte functions in health and disease. Copyright © 2014 Wiley Periodicals, Inc.

Reciprocal regulation of insulin and plasma 5'-AMP in glucose homeostasis in mice.

PubMed

Xia, Lin; Wang, Zhongqiu; Zhang, Ying; Yang, Xiao; Zhan, Yibei; Cheng, Rui; Wang, Shiming; Zhang, Jianfa

2015-03-01

A previous investigation has demonstrated that plasma 5'-AMP (pAMP) exacerbates and causes hyperglycemia in diabetic mice. However, the crosstalk between pAMP and insulin signaling to regulate glucose homeostasis has not been investigated in depth. In this study, we showed that the blood glucose level was more dependent on the ratio of insulin to pAMP than on the absolute level of these two factors. Administration of 5'-AMP significantly attenuated the insulin-stimulated insulin receptor (IR) autophosphorylation in the liver and muscle tissues, resulting in the inhibition of downstream AKT phosphorylation. A docking analysis indicated that adenosine was a potential inhibitor of IR tyrosine kinase. Moreover, the 5'-AMP treatment elevated the ATP level in the pancreas and in the isolated islets, stimulating insulin secretion and increasing the plasma level of insulin. The insulin administration decreased the 5'-AMP-induced hyper-adenosine level by the up-regulation of adenosine kinase activities. Our results indicate that blood glucose homeostasis is reciprocally regulated by pAMP and insulin. © 2015 Society for Endocrinology.

Input-output Transfer Function Analysis of a Photometer Circuit Based on an Operational Amplifier.

PubMed

Hernandez, Wilmar

2008-01-09

In this paper an input-output transfer function analysis based on the frequencyresponse of a photometer circuit based on operational amplifier (op amp) is carried out. Opamps are universally used in monitoring photodetectors and there are a variety of amplifierconnections for this purpose. However, the electronic circuits that are usually used to carryout the signal treatment in photometer circuits introduce some limitations in theperformance of the photometers that influence the selection of the op amps and otherelectronic devices. For example, the bandwidth, slew-rate, noise, input impedance and gain,among other characteristics of the op amp, are often the performance limiting factors ofphotometer circuits. For this reason, in this paper a comparative analysis between twophotodiode amplifier circuits is carried out. One circuit is based on a conventional currentto-voltage converter connection and the other circuit is based on a robust current-to-voltageconverter connection. The results are satisfactory and show that the photodiode amplifierperformance can be improved by using robust control techniques.

A novel cysteine-rich antifungal peptide ToAMP4 from Taraxacum officinale Wigg. flowers.

PubMed

Astafieva, A A; Rogozhin, Eugene A; Andreev, Yaroslav A; Odintsova, T I; Kozlov, S A; Grishin, Eugene V; Egorov, Tsezi A

2013-09-01

A novel peptide named ToAMP4 was isolated from Taraxacum officinale Wigg. flowers by a combination of acetic acid extraction and different types of chromatography: affinity, size-exclusion, and RP-HPLC. The amino acid sequence of ToAMP4 was determined by automated Edman degradation. The peptide is basic, consists of 41 amino acids, and incorporates three disulphide bonds. Due to the unusual cysteine spacing pattern, ToAMP4 does not belong to any known plant AMP family, but classifies together with two other antimicrobial peptides ToAMP1 and ToAMP2 previously isolated from the dandelion flowers. To study the biological activity of ToAMP4, it was successfully produced in a prokaryotic expression system as a fusion protein with thioredoxin. The recombinant peptide was shown to be identical to the native ToAMP4 by chromatographic behavior, molecular mass, and N-terminal amino acid sequence. The peptide displays broad-spectrum antifungal activity against important phytopathogens. Two ToAMP4-mediated inhibition strategies depending on the fungus were demonstrated. The results obtained add to our knowledge on the structural and functional diversity of AMPs in plants. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System

PubMed Central

Zahid, M. Shamim Hasan; Awasthi, Sharda Prasad; Asakura, Masahiro; Chatterjee, Shruti; Hinenoya, Atsushi; Faruque, Shah M.; Yamasaki, Shinji

2015-01-01

Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT) and toxin coregulated pilus (TCP), the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP)-cAMP receptor protein (CRP) is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens. PMID:26361388

Suppression of Virulence of Toxigenic Vibrio cholerae by Anethole through the Cyclic AMP (cAMP)-cAMP Receptor Protein Signaling System.

PubMed

Zahid, M Shamim Hasan; Awasthi, Sharda Prasad; Asakura, Masahiro; Chatterjee, Shruti; Hinenoya, Atsushi; Faruque, Shah M; Yamasaki, Shinji

2015-01-01

Use of natural compounds as antivirulence drugs could be an alternative therapeutic approach to modify the outcome of bacterial infections, particularly in view of growing resistance to available antimicrobials. Here, we show that sub-bactericidal concentration of anethole, a component of sweet fennel seed, could suppress virulence potential in O1 El Tor biotype strains of toxigenic Vibrio cholerae, the causative agent of the ongoing 7th cholera pandemic. The expression of cholera toxin (CT) and toxin coregulated pilus (TCP), the major virulence factors of V. cholerae, is controlled through a regulatory cascade involving activation of ToxT with synergistic coupling interaction of ToxR/ToxS with TcpP/TcpH. We present evidence that anethole inhibits in vitro expression of CT and TCP in a toxT-dependent but toxR/toxS-independent manner and through repression of tcpP/tcpH, by using bead-ELISA, western blotting and quantitative real-time RT-PCR assays. The cyclic AMP (cAMP)-cAMP receptor protein (CRP) is a well-studied global signaling system in bacterial pathogens, and this complex is known to suppress expression of tcpP/tcpH in V. cholerae. We find that anethole influences the virulence regulatory cascade by over-expressing cyaA and crp genes. Moreover, suppression of toxigenic V. cholerae-mediated fluid accumulation in ligated ileum of rabbit by anethole demonstrates its potentiality as an antivirulence drug candidate against the diseases caused by toxigenic V. cholerae. Taken altogether, these results revealing a mechanism of virulence inhibition in V. cholerae by the natural compound anethole, may have relevance in designing antivirulence compounds, particularly against multiple antibiotic resistant bacterial pathogens.

The effects of acute pesticide exposure on neuroblastoma cells chronically exposed to diazinon.

PubMed

Axelrad, J C; Howard, C V; McLean, W G

2003-03-14

Speculation about potential neurotoxicity due to chronic exposure to low doses of organophosphate (OP) pesticides is not yet supported by experimental evidence. The objective of this work was to use a cell culture model of chronic OP exposure to determine if such exposure can alter the sensitivity of nerve cells to subsequent acute exposure to OPs or other compounds. NB2a neuroblastoma cells were grown in the presence of 25 microM diazinon for 8 weeks. The OP was then withdrawn and the cells were induced to differentiate in the presence of various other pesticides or herbicides, including OPs and OP-containing formulations. The resulting outgrowth of neurite-like structures was measured by light microscopy and quantitative image analysis and the IC(50) for each OP or formulation was calculated. The IC(50) values in diazinon-pre-exposed cells were compared with the equivalent values in cells not pre-exposed to diazinon. The IC(50) for inhibition of neurite outgrowth by acute application of diazinon, pyrethrum, glyphosate or a commercial formulation of glyphosate was decreased by between 20 and 90% after pre-treatment with diazinon. In contrast, the IC(50) for pirimiphos methyl was unaffected and those for phosmet or chlorpyrifos were increased by between 1.5- and 3-fold. Treatment of cells with chlorpyrifos or with a second glyphosate-containing formulation led to the formation of abnormal neurite-like structures in diazinon-pre-exposed cells. The data support the view that chronic exposure to an OP may reduce the threshold for toxicity of some, but by no means all, environmental agents.

The cyclic AMP cascade is altered in the fragile X nervous system.

PubMed

Kelley, Daniel J; Davidson, Richard J; Elliott, Jamie L; Lahvis, Garet P; Yin, Jerry C P; Bhattacharyya, Anita

2007-09-26

Fragile X syndrome (FX), the most common heritable cause of mental retardation and autism, is a developmental disorder characterized by physical, cognitive, and behavioral deficits. FX results from a trinucleotide expansion mutation in the fmr1 gene that reduces levels of fragile X mental retardation protein (FMRP). Although research efforts have focused on FMRP's impact on mGluR signaling, how the loss of FMRP leads to the individual symptoms of FX is not known. Previous studies on human FX blood cells revealed alterations in the cyclic adenosine 3', 5'-monophosphate (cAMP) cascade. We tested the hypothesis that cAMP signaling is altered in the FX nervous system using three different model systems. Induced levels of cAMP in platelets and in brains of fmr1 knockout mice are substantially reduced. Cyclic AMP induction is also significantly reduced in human FX neural cells. Furthermore, cAMP production is decreased in the heads of FX Drosophila and this defect can be rescued by reintroduction of the dfmr gene. Our results indicate that a robust defect in cAMP production in FX is conserved across species and suggest that cAMP metabolism may serve as a useful biomarker in the human disease population. Reduced cAMP induction has implications for the underlying causes of FX and autism spectrum disorders. Pharmacological agents known to modulate the cAMP cascade may be therapeutic in FX patients and can be tested in these models, thus supplementing current efforts centered on mGluR signaling.

Involvement of hippocampal cAMP/cAMP-dependent protein kinase signaling pathways in a late memory consolidation phase of aversively motivated learning in rats

PubMed Central

Bernabeu, Ramon; Bevilaqua, Lia; Ardenghi, Patricia; Bromberg, Elke; Schmitz, Paulo; Bianchin, Marino; Izquierdo, Ivan; Medina, Jorge H.

1997-01-01

cAMP/cAMP-dependent protein kinase (PKA) signaling pathway has been recently proposed to participate in both the late phase of long term potentiation in the hippocampus and in the late, protein synthesis-dependent phase of memory formation. Here we report that a late memory consolidation phase of an inhibitory avoidance learning is regulated by an hippocampal cAMP signaling pathway that is activated, at least in part, by D1/D5 receptors. Bilateral infusion of SKF 38393 (7.5 μg/side), a D1/D5 receptor agonist, into the CA1 region of the dorsal hippocampus, enhanced retention of a step-down inhibitory avoidance when given 3 or 6 h, but not immediately (0 h) or 9 h, after training. In contrast, full retrograde amnesia was obtained when SCH 23390 (0.5 μg/side), a D1/D5 receptor antagonist, was infused into the hippocampus 3 or 6 h after training. Intrahippocampal infusion of 8Br-cAMP (1.25 μg/side), or forskolin (0.5 μg/side), an activator of adenylyl cyclase, enhanced memory when given 3 or 6 h after training. KT5720 (0.5 μg/side), a specific inhibitor of PKA, hindered memory consolidation when given immediately or 3 or 6 h posttraining. Rats submitted to the avoidance task showed learning-specific increases in hippocampal 3H-SCH 23390 binding and in the endogenous levels of cAMP 3 and 6 h after training. In addition, PKA activity and P-CREB (phosphorylated form of cAMP responsive element binding protein) immunoreactivity increased in the hippocampus immediately and 3 and 6 h after training. Together, these findings suggest that the late phase of memory consolidation of an inhibitory avoidance is modulated cAMP/PKA signaling pathways in the hippocampus. PMID:9192688

Spatiotemporal regulation of cAMP signaling controls the human trophoblast fusion

PubMed Central

Gerbaud, Pascale; Taskén, Kjetil; Pidoux, Guillaume

2015-01-01

During human placentation, mononuclear cytotrophoblasts fuse to form multinucleated syncytia ensuring hormonal production and nutrient exchanges between the maternal and fetal circulation. Syncytial formation is essential for the maintenance of pregnancy and for fetal growth. The cAMP signaling pathway is the major route to trigger trophoblast fusion and its activation results in phosphorylation of specific intracellular target proteins, in transcription of fusogenic genes and assembly of macromolecular protein complexes constituting the fusogenic machinery at the plasma membrane. Specificity in cAMP signaling is ensured by generation of localized pools of cAMP controlled by cAMP phosphodiesterases (PDEs) and by discrete spatial and temporal activation of protein kinase A (PKA) in supramolecular signaling clusters inside the cell organized by A-kinase-anchoring proteins (AKAPs) and by organization of signal termination by protein phosphatases (PPs). Here we present original observations on the available components of the cAMP signaling pathway in the human placenta including PKA, PDE, and PP isoforms as well as AKAPs. We continue to discuss the current knowledge of the spatiotemporal regulation of cAMP signaling triggering trophoblast fusion. PMID:26441659

Riboswitches in eubacteria sense the second messenger c-di-AMP

PubMed Central

Nelson, James W.; Sudarsan, Narasimhan; Furukawa, Kazuhiro; Weinberg, Zasha; Wang, Joy X.; Breaker, Ronald R.

2013-01-01

Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered bacterial second messenger implicated in the control of cell wall metabolism, osmotic stress responses, and sporulation. However, the mechanisms by which c-di-AMP triggers these physiological responses have remained largely unknown. Intriguingly, a candidate riboswitch class called ydaO associates with numerous genes involved in these same processes. Although a representative ydaO motif RNA recently was reported to weakly bind ATP, we report that numerous members of this noncoding RNA class selectively respond to c-di-AMP with sub-nanomolar affinity. Our findings resolve the mystery regarding the primary ligand for this extremely common riboswitch class and expose a major portion of the super-regulon of genes that are controlled by the widespread bacterial second messenger c-di-AMP. PMID:24141192

The open cluster IC 4665

NASA Technical Reports Server (NTRS)

Prosser, Charles F.

1993-01-01

The results of a combined astrometric, photometric, and spectroscopic program to identify members of the open cluster IC 4665 are presented. Numerous new proper motion/photometric candidate members and at least 23 M dwarfs with H-alpha emission have been identified. A reanalysis of IC 4665 age using different methods yields conflicting results ranging from about 3 X 10 exp 7 yr to the age of the Pleiades. This study provides a list of candidate cluster members in the intermediate and low-mass regime of this cluster. Future spectroscopic observations of these candidates should eventually identify true cluster members.

A possible signal-coupling role for cyclic AMP during endocytosis in Amoeba proteus.

PubMed

Prusch, R D; Roscoe, J C

1993-01-01

Cytoplasmic levels of cAMP in Amoeba proteus were measured utilizing radioimmunoassays under control conditions and when stimulated by inducers of either pinocytosis or phagocytosis. In control cells, cytoplasmic cAMP levels were approximately 0.39 pM/mg cells. When exposed to either chemotactic peptide or mannose which stimulate phagocytosis in the amoeba, there is a rapid doubling of the cAMP level within 45 sec of stimulation which then returns to the control level within 3-5 min. Theophylline prolongs the elevation of cytoplasmic cAMP in stimulated cells and is also capable of eliciting food vacuole formation in the amoeba. In addition isoproterenol also causes food vacuole formation in the amoeba as well as a large and prolonged increase in cytoplasmic cAMP levels. Inducers of pinocytosis (BSA and Na Cl) also elicit changes in cytoplasmic cAMP in the amoeba, but the response appears to differ from that elicited by inducers of phagocytosis in that the peak cAMP levels are broader and biphasic. It is concluded that cAMP plays a signal-coupling role during the early phases of both forms of endocytosis in Amoeba proteus.

The utility of a "trauma 1 OP" activation at a level 1 pediatric trauma center.

PubMed

Hunt, Madison M; Stevens, Austin M; Hansen, Kristine W; Fenton, Stephen J

2017-02-01

To expedite flow of injured children suspected to require operative intervention, a "trauma 1 OP" (T1OP) activation classification was created. The purpose of this study was to review this strategy at a level 1 pediatric trauma center. A retrospective review of T1OP activations between 2003 and 2015 was performed. Children suspected of requiring neurosurgical intervention were classified as trauma 1 OP neuro (T1OP(N)). Comparisons were made to trauma 1 (T1) patients who required emergent operative intervention, excluding orthopedic injuries. Overall, 461 T1OP activations occurred (72% T1OP(N)) compared to 129 T1 activations requiring emergent surgery. Demographics were not significantly different between groups, although T1OP patients were slightly younger and more often experienced falls or were victims of abuse. Compared to T1 activations, T1OP activations had a significantly higher mortality rate (21% vs. 7%, p<0.001). Repeat head imaging was more common in the T1OP(N) group compared to imaged children in the T1 group (20% vs. 37%, p=0.05). T1OP(N) patients more often went directly to the OR (45% vs. 33%, p=0.02) and did so in a significantly faster period of time (32min vs. 53min, p<0.001). Use of the T1OP activations appropriately triaged surgical patients, resulting in significantly faster transport times to the OR. II, prognosis study. Copyright © 2017 Elsevier Inc. All rights reserved.

cAMP-responsive Element-binding Protein (CREB) and cAMP Co-regulate Activator Protein 1 (AP1)-dependent Regeneration-associated Gene Expression and Neurite Growth*

PubMed Central

Ma, Thong C.; Barco, Angel; Ratan, Rajiv R.; Willis, Dianna E.

2014-01-01

To regenerate damaged axons, neurons must express a cassette of regeneration-associated genes (RAGs) that increases intrinsic growth capacity and confers resistance to extrinsic inhibitory cues. Here we show that dibutyrl-cAMP or forskolin combined with constitutive-active CREB are superior to either agent alone in driving neurite growth on permissive and inhibitory substrates. Of the RAGs examined, only arginase 1 (Arg1) expression correlated with the increased neurite growth induced by the cAMP/CREB combination, both of which were AP1-dependent. This suggests that cAMP-induced AP1 activity is necessary and interacts with CREB to drive expression of RAGs relevant for regeneration and demonstrates that combining a small molecule (cAMP) with an activated transcription factor (CREB) stimulates the gene expression necessary to enhance axonal regeneration. PMID:25296755

Effect of cAMP on short-circuit current in isolated human ciliary body.

PubMed

Wu, Ren-yi; Ma, Ning; Hu, Qian-qian

2013-07-01

Cyclic adenosine monophosphate (cAMP) could activate chloride channels in bovine ciliary body and trigger an increase in the ionic current (short-circuit current, Isc) across the ciliary processes in pigs. The purpose of this study was to investigate how cAMP modulates Isc in isolated human ciliary processes and the possible involvement of chloride transport across the tissue in cAMP-induced Isc change. In an Ussing-type chamber system, the Isc changes induced by the cAMP analogue 8-bromo-cAMP and an adenylyl cyclase activator forskolin in isolated human ciliary processes were assessed. The involvement of Cl(-) component in the bath solution was investigated. The effect of Cl(-) channel (10 µmol/L niflumic acid and 1 mmol/L 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)), K(+) channel (10 mmol/L tetraethylammonium chloride (TEA)), or Na(+) channel blockers (1 mmol/L amiloride) on 8-bromo-cAMP-induced Isc change was also studied. Dose-dependently, 8-bromo-cAMP (10 nmol/L-30 µmol/L) or forskolin (10 nmol/L-3 µmol/L) increased Isc across the ciliary processes with an increase in negative potential difference on the non-pigmented epithelium (NPE) side of the tissue. Isc increase induced by 8-bromo-cAMP was more pronounced when the drug was applied on the NPE side than on the pigmented epithelium side. When the tissue was bathed in low Cl(-) solutions, the Isc increase was significantly inhibited. Finally, niflumic acid and DIDS, but not TEA or amiloride, significantly prevented the Isc increase induced by 8-bromo-cAMP. cAMP stimulates stroma-to-aqueous anionic transport in isolated human ciliary processes. Chloride is likely to be among the ions, the transportation of which across the tissue is triggered by cAMP, suggesting the potential role of cAMP in the process of aqueous humor formation in human eyes.

Semiconductor/High-Tc-Superconductor Hybrid ICs

NASA Technical Reports Server (NTRS)

Burns, Michael J.

1995-01-01

Hybrid integrated circuits (ICs) containing both Si-based semiconducting and YBa(2)Cu(3)O(7-x) superconducting circuit elements on sapphire substrates developed. Help to prevent diffusion of Cu from superconductors into semiconductors. These hybrid ICs combine superconducting and semiconducting features unavailable in superconducting or semiconducting circuitry alone. For example, complementary metal oxide/semiconductor (CMOS) readout and memory devices integrated with fast-switching Josephson-junction super-conducting logic devices and zero-resistance interconnections.

cAMP Stimulates Transepithelial Short-Circuit Current and Fluid Transport Across Porcine Ciliary Epithelium.

PubMed

Cheng, Angela King-Wah; Civan, Mortimer M; To, Chi-Ho; Do, Chi-Wai

2016-12-01

To investigate the effects of cAMP on transepithelial electrical parameters and fluid transport across porcine ciliary epithelium. Transepithelial electrical parameters were determined by mounting freshly isolated porcine ciliary epithelium in a modified Ussing chamber. Similarly, fluid movement across intact ciliary body was measured with a custom-made fluid flow chamber. Addition of 1, 10, and 100 μM 8-Br-cAMP (cAMP) to the aqueous side (nonpigmented ciliary epithelium, NPE) induced a sustained increase in short-circuit current (Isc). Addition of niflumic acid (NFA) to the aqueous surface effectively blocked the cAMP-induced Isc stimulation. The administration of cAMP to the stromal side (pigmented ciliary epithelium, PE) triggered a significant stimulation of Isc only at 100 μM. No additive effect was observed with bilateral application of cAMP. Likewise, forskolin caused a significant stimulation of Isc when applied to the aqueous side. Concomitantly, cAMP and forskolin increased fluid transport across porcine ciliary epithelium, and this stimulation was effectively inhibited by aqueous NFA. Depleting Cl- in the bathing solution abolished the baseline Isc and inhibited the subsequent stimulation by cAMP. Pretreatment with protein kinase A (PKA) blockers (H89/KT5720) significantly inhibited the cAMP- and forskolin-induced Isc responses. Our results suggest that cAMP triggers a sustained stimulation of Cl- and fluid transport across porcine ciliary epithelium; Cl- channels in the NPE cells are potentially a cellular site for this PKA-sensitive cAMP-mediated response.

Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific phosphodiesterase-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kucka, Marek; Pogrmic-Majkic, Kristina; Fa, Svetlana

2012-11-15

Atrazine, one of the most commonly used herbicides worldwide, acts as an endocrine disruptor, but the mechanism of its action has not been characterized. In this study, we show that atrazine rapidly increases cAMP levels in cultured rat pituitary and testicular Leydig cells in a concentration-dependent manner, but less effectively than 3-isobutyl-1-methylxanthine, a competitive non-specific inhibitor of phosphodiesterases (PDEs). In forskolin (an activator of adenylyl cyclase)- and probenecid (an inhibitor of cyclic nucleotide transporters)-treated cells, but not in 3-isobutyl-1-methylxanthine-treated cells, atrazine further increased cAMP levels, indicating that inhibition of PDEs accounts for accumulation of cAMP. In contrast to cAMP, atrazinemore » did not alter cGMP levels, further indicating that it inhibits cAMP-specific PDEs. Atrazine-induced changes in cAMP levels were sufficient to stimulate prolactin release in pituitary cells and androgen production in Leydig cells, indicating that it acts as an endocrine disrupter both in cells that secrete by exocytosis of prestored hormones and in cells that secrete by de novo hormone synthesis. Rolipram abolished the stimulatory effect of atrazine on cAMP release in both cell types, suggesting that it acts as an inhibitor of PDE4s, isoforms whose mRNA transcripts dominate in pituitary and Leydig cells together with mRNA for PDE8A. In contrast, immortalized lacto-somatotrophs showed low expression of these mRNA transcripts and several fold higher cAMP levels compared to normal pituitary cells, and atrazine was unable to further increase cAMP levels. These results indicate that atrazine acts as a general endocrine disrupter by inhibiting cAMP-specific PDE4s. -- Highlights: ► Atrazine stimulates cAMP accumulation in pituitary and Leydig cells. ► Atrazine also stimulates PRL and androgens secretion. ► Stimulatory effects of atrazine were abolished in cells with IBMX-inhibited PDEs. ► Atrazine specificity toward

Status of the Signals of Opportunity Airborne Demonstrator (SoOp-AD)

NASA Technical Reports Server (NTRS)

Garrison, Jim; Lin, Yao-Cheng; Piepmeier, Jeff; Knuble, Joe; Hersey, Ken; Du Toit, Cornelus; Joseph, Alicia; Deshpande, Manohar; Alikakos, George; O'Brien, Steve;

The role of the RAS pathway in iAMP21-ALL

PubMed Central

Ryan, S L; Matheson, E; Grossmann, V; Sinclair, P; Bashton, M; Schwab, C; Towers, W; Partington, M; Elliott, A; Minto, L; Richardson, S; Rahman, T; Keavney, B; Skinner, R; Bown, N; Haferlach, T; Vandenberghe, P; Haferlach, C; Santibanez-Koref, M; Moorman, A V; Kohlmann, A; Irving, J A E; Harrison, C J

2016-01-01

Intrachromosomal amplification of chromosome 21 (iAMP21) identifies a high-risk subtype of acute lymphoblastic leukaemia (ALL), requiring intensive treatment to reduce their relapse risk. Improved understanding of the genomic landscape of iAMP21-ALL will ascertain whether these patients may benefit from targeted therapy. We performed whole-exome sequencing of eight iAMP21-ALL samples. The mutation rate was dramatically disparate between cases (average 24.9, range 5–51) and a large number of novel variants were identified, including frequent mutation of the RAS/MEK/ERK pathway. Targeted sequencing of a larger cohort revealed that 60% (25/42) of diagnostic iAMP21-ALL samples harboured 42 distinct RAS pathway mutations. High sequencing coverage demonstrated heterogeneity in the form of multiple RAS pathway mutations within the same sample and diverse variant allele frequencies (VAFs) (2–52%), similar to other subtypes of ALL. Constitutive RAS pathway activation was observed in iAMP21 samples that harboured mutations in the predominant clone (⩾35% VAF). Viable iAMP21 cells from primary xenografts showed reduced viability in response to the MEK1/2 inhibitor, selumetinib, in vitro. As clonal (⩾35% VAF) mutations were detected in 26% (11/42) of iAMP21-ALL, this evidence of response to RAS pathway inhibitors may offer the possibility to introduce targeted therapy to improve therapeutic efficacy in these high-risk patients. PMID:27168466

Nuclear localization of the dehydrin OpsDHN1 is determined by histidine-rich motif.

PubMed

Hernández-Sánchez, Itzell E; Maruri-López, Israel; Ferrando, Alejandro; Carbonell, Juan; Graether, Steffen P; Jiménez-Bremont, Juan F

2015-01-01

The cactus OpsDHN1 dehydrin belongs to a large family of disordered and highly hydrophilic proteins known as Late Embryogenesis Abundant (LEA) proteins, which accumulate during the late stages of embryogenesis and in response to abiotic stresses. Herein, we present the in vivo OpsDHN1 subcellular localization by N-terminal GFP translational fusion; our results revealed a cytoplasmic and nuclear localization of the GFP::OpsDHN1 protein in Nicotiana benthamiana epidermal cells. In addition, dimer assembly of OpsDHN1 in planta using a Bimolecular Fluorescence Complementation (BiFC) approach was demonstrated. In order to understand the in vivo role of the histidine-rich motif, the OpsDHN1-ΔHis version was produced and assayed for its subcellular localization and dimer capability by GFP fusion and BiFC assays, respectively. We found that deletion of the OpsDHN1 histidine-rich motif restricted its localization to cytoplasm, but did not affect dimer formation. In addition, the deletion of the S-segment in the OpsDHN1 protein affected its nuclear localization. Our data suggest that the deletion of histidine-rich motif and S-segment show similar effects, preventing OpsDHN1 from getting into the nucleus. Based on these results, the histidine-rich motif is proposed as a targeting element for OpsDHN1 nuclear localization.

Nuclear localization of the dehydrin OpsDHN1 is determined by histidine-rich motif

PubMed Central

Hernández-Sánchez, Itzell E.; Maruri-López, Israel; Ferrando, Alejandro; Carbonell, Juan; Graether, Steffen P.; Jiménez-Bremont, Juan F.

2015-01-01

The cactus OpsDHN1 dehydrin belongs to a large family of disordered and highly hydrophilic proteins known as Late Embryogenesis Abundant (LEA) proteins, which accumulate during the late stages of embryogenesis and in response to abiotic stresses. Herein, we present the in vivo OpsDHN1 subcellular localization by N-terminal GFP translational fusion; our results revealed a cytoplasmic and nuclear localization of the GFP::OpsDHN1 protein in Nicotiana benthamiana epidermal cells. In addition, dimer assembly of OpsDHN1 in planta using a Bimolecular Fluorescence Complementation (BiFC) approach was demonstrated. In order to understand the in vivo role of the histidine-rich motif, the OpsDHN1-ΔHis version was produced and assayed for its subcellular localization and dimer capability by GFP fusion and BiFC assays, respectively. We found that deletion of the OpsDHN1 histidine-rich motif restricted its localization to cytoplasm, but did not affect dimer formation. In addition, the deletion of the S-segment in the OpsDHN1 protein affected its nuclear localization. Our data suggest that the deletion of histidine-rich motif and S-segment show similar effects, preventing OpsDHN1 from getting into the nucleus. Based on these results, the histidine-rich motif is proposed as a targeting element for OpsDHN1 nuclear localization. PMID:26442018

Quantitative Proteomics Analysis of the cAMP/Protein Kinase A Signaling Pathway

PubMed Central

2012-01-01

To define the proteins whose expression is regulated by cAMP and protein kinase A (PKA), we used a quantitative proteomics approach in studies of wild-type (WT) and kin- (PKA-null) S49 murine T lymphoma cells. We also compared the impact of endogenous increases in the level of cAMP [by forskolin (Fsk) and the phosphodiesterase inhibitor isobutylmethylxanthine (IBMX)] or by a cAMP analogue (8-CPT-cAMP). We identified 1056 proteins in WT and kin- S49 cells and found that 8-CPT-cAMP and Fsk with IBMX produced differences in protein expression. WT S49 cells had a correlation coefficient of 0.41 between DNA microarray data and the proteomics analysis in cells incubated with 8-CPT-cAMP for 24 h and a correlation coefficient of 0.42 between the DNA microarray data obtained at 6 h and the changes in protein expression after incubation with 8-CPT-cAMP for 24 h. Glutathione reductase (Gsr) had a higher level of basal expression in kin- S49 cells than in WT cells. Consistent with this finding, kin- cells are less sensitive to cell killing and generation of malondialdehyde than are WT cells incubated with H2O2. Cyclic AMP acting via PKA thus has a broad impact on protein expression in mammalian cells, including in the regulation of Gsr and oxidative stress. PMID:23110364

A Way to End the IC Designer Shortage.

ERIC Educational Resources Information Center

Robinson, Arthur L.

1980-01-01

Discusses the problem of the shortage of engineers capable of designing advanced integrated circuits (IC) and presents some suggestions for increasing the number of IC designers in universities and semiconductor companies. (HM)

Atmosphere, Magnetosphere and Plasmas in Space (AMPS). Spacelab payload definition study. Volume 7, book 2: AMPS phase C/D analysis and planning document

NASA Technical Reports Server (NTRS)

1976-01-01

The results are presented of the AMPS Phase C/D (Design, Development, and Operations) program analysis and planning effort. Cost and schedule estimates are included. Although the AMPS program has been specifically addressed, these task descriptions are basically adaptable to a broader-based program incorporating additional or different Spacelab/orbiter payloads.

Relaxation oscillator-realized artificial electronic neurons, their responses, and noise

NASA Astrophysics Data System (ADS)

Lim, Hyungkwang; Ahn, Hyung-Woo; Kornijcuk, Vladimir; Kim, Guhyun; Seok, Jun Yeong; Kim, Inho; Hwang, Cheol Seong; Jeong, Doo Seok

2016-05-01

A proof-of-concept relaxation oscillator-based leaky integrate-and-fire (ROLIF) neuron circuit is realized by using an amorphous chalcogenide-based threshold switch and non-ideal operational amplifier (op-amp). The proposed ROLIF neuron offers biologically plausible features such as analog-type encoding, signal amplification, unidirectional synaptic transmission, and Poisson noise. The synaptic transmission between pre- and postsynaptic neurons is achieved through a passive synapse (simple resistor). The synaptic resistor coupled to the non-ideal op-amp realizes excitatory postsynaptic potential (EPSP) evolution that evokes postsynaptic neuron spiking. In an attempt to generalize our proposed model, we theoretically examine ROLIF neuron circuits adopting different non-ideal op-amps having different gains and slew rates. The simulation results indicate the importance of gain in postsynaptic neuron spiking, irrespective of the slew rate (as long as the rate exceeds a particular value), providing the basis for the ROLIF neuron circuit design. Eventually, the behavior of a postsynaptic neuron in connection to multiple presynaptic neurons via synapses is highlighted in terms of EPSP evolution amid simultaneously incident asynchronous presynaptic spikes, which in fact reveals an important role of the random noise in spatial integration.A proof-of-concept relaxation oscillator-based leaky integrate-and-fire (ROLIF) neuron circuit is realized by using an amorphous chalcogenide-based threshold switch and non-ideal operational amplifier (op-amp). The proposed ROLIF neuron offers biologically plausible features such as analog-type encoding, signal amplification, unidirectional synaptic transmission, and Poisson noise. The synaptic transmission between pre- and postsynaptic neurons is achieved through a passive synapse (simple resistor). The synaptic resistor coupled to the non-ideal op-amp realizes excitatory postsynaptic potential (EPSP) evolution that evokes postsynaptic

Intrasteric control of AMPK via the gamma1 subunit AMP allosteric regulatory site.

PubMed

Adams, Julian; Chen, Zhi-Ping; Van Denderen, Bryce J W; Morton, Craig J; Parker, Michael W; Witters, Lee A; Stapleton, David; Kemp, Bruce E

2004-01-01

AMP-activated protein kinase (AMPK) is a alphabetagamma heterotrimer that is activated in response to both hormones and intracellular metabolic stress signals. AMPK is regulated by phosphorylation on the alpha subunit and by AMP allosteric control previously thought to be mediated by both alpha and gamma subunits. Here we present evidence that adjacent gamma subunit pairs of CBS repeat sequences (after Cystathionine Beta Synthase) form an AMP binding site related to, but distinct from the classical AMP binding site in phosphorylase, that can also bind ATP. The AMP binding site of the gamma(1) CBS1/CBS2 pair, modeled on the structures of the CBS sequences present in the inosine monophosphate dehydrogenase crystal structure, contains three arginine residues 70, 152, and 171 and His151. The yeast gamma homolog, snf4 contains a His151Gly substitution, and when this is introduced into gamma(1), AMP allosteric control is substantially lost and explains why the yeast snf1p/snf4p complex is insensitive to AMP. Arg70 in gamma(1) corresponds to the site of mutation in human gamma(2) and pig gamma(3) genes previously identified to cause an unusual cardiac phenotype and glycogen storage disease, respectively. Mutation of any of AMP binding site Arg residues to Gln substantially abolishes AMP allosteric control in expressed AMPK holoenzyme. The Arg/Gln mutations also suppress the previously described inhibitory properties of ATP and render the enzyme constitutively active. We propose that ATP acts as an intrasteric inhibitor by bridging the alpha and gamma subunits and that AMP functions to derepress AMPK activity.

Cyclic AMP Enhances TGFβ Responses of Breast Cancer Cells by Upregulating TGFβ Receptor I Expression

PubMed Central

Oerlecke, Ilka; Bauer, Elke; Dittmer, Angela; Leyh, Benjamin; Dittmer, Jürgen

2013-01-01

Cellular functions are regulated by complex networks of many different signaling pathways. The TGFβ and cAMP pathways are of particular importance in tumor progression. We analyzed the cross-talk between these pathways in breast cancer cells in 2D and 3D cultures. We found that cAMP potentiated TGFβ-dependent gene expression by enhancing Smad3 phosphorylation. Higher levels of total Smad3, as observed in 3D-cultured cells, blocked this effect. Two Smad3 regulating proteins, YAP (Yes-associated protein) and TβRI (TGFβ receptor 1), were responsive to cAMP. While YAP had little effect on TGFβ-dependent expression and Smad3 phosphorylation, a constitutively active form of TβRI mimicked the cAMP effect on TGFβ signaling. In 3D-cultured cells, which show much higher levels of TβRI and cAMP, TβRI was unresponsive to cAMP. Upregulation of TβRI expression by cAMP was dependent on transcription. A proximal TβRI promoter fragment was moderately, but significantly activated by cAMP suggesting that cAMP increases TβRI expression at least partially by activating TβRI transcription. Neither the cAMP-responsive element binding protein (CREB) nor the TβRI-regulating transcription factor Six1 was required for the cAMP effect. An inhibitor of histone deacetylases alone or together with cAMP increased TβRI expression by a similar extent as cAMP alone suggesting that cAMP may exert its effect by interfering with histone acetylation. Along with an additive stimulatory effect of cAMP and TGFβ on p21 expression an additive inhibitory effect of these agents on proliferation was observed. Finally, we show that mesenchymal stem cells that interact with breast cancer cells can simultaneously activate the cAMP and TGFβ pathways. In summary, these data suggest that combined effects of cAMP and TGFβ, as e.g. induced by mesenchymal stem cells, involve the upregulation of TβRI expression on the transcriptional level, likely due to changes in histone acetylation. As a consequence

Inhibition of vascular smooth muscle growth via signaling crosstalk between AMP-activated protein kinase and cAMP-dependent protein kinase

PubMed Central

Stone, Joshua D.; Narine, Avinash; Tulis, David A.

2012-01-01

Abnormal vascular smooth muscle (VSM) growth is central in the pathophysiology of vascular disease yet fully effective therapies to curb this growth are lacking. Recent findings from our lab and others support growth control of VSM by adenosine monophosphate (AMP)-based approaches including the metabolic sensor AMP-activated protein kinase (AMPK) and cAMP-dependent protein kinase (PKA). Molecular crosstalk between AMPK and PKA has been previously suggested, yet the extent to which this occurs and its biological significance in VSM remain unclear. Considering their common AMP backbone and similar signaling characteristics, we hypothesized that crosstalk exists between AMPK and PKA in the regulation of VSM growth. Using rat primary VSM cells (VSMC), the AMPK agonist AICAR increased AMPK activity and phosphorylation of the catalytic Thr172 site on AMPK. Interestingly, AICAR also phosphorylated a suspected PKA-inhibitory Ser485 site on AMPK, and these cumulative events were reversed by the PKA inhibitor PKI suggesting possible PKA-mediated regulation of AMPK. AICAR also increased PKA activity in a reversible fashion. The cAMP stimulator forskolin increased PKA activity and completely ameliorated Ser/Thr protein phosphatase-2C activity, suggesting a potential mechanism of AMPK modulation by PKA since inhibition of PKA by PKI reduced AMPK activity. Functionally, AMPK inhibited serum-stimulated cell cycle progression and cellular proliferation; however, PKA failed to do so. Moreover, AMPK and PKA reduced PDGF-β-stimulated VSMC migration. Collectively, these results show that AMPK is capable of reducing VSM growth in both anti-proliferative and anti-migratory fashion. Furthermore, these data suggest that AMPK may be modulated by PKA and that positive feedback may exist between these two systems. These findings reveal a discrete nexus between AMPK and PKA in VSM and provide basis for metabolically-directed targets in reducing pathologic VSM growth. PMID:23112775

Continuous activation of pituitary adenylate cyclase-activating polypeptide receptors elicits antipodal effects on cyclic AMP and inositol phospholipid signaling pathways in CATH.a cells: role of protein synthesis and protein kinases.

PubMed

Muller, A; Lutz-Bucher, B; Kienlen-Campard, P; Koch, B; Loeffler, J P

1998-04-01

Continuous exposure of cells to agonists develops a process that determines the extent to which the cells eventually respond to further stimuli. Here we used CATH.a cells (a catecholaminergic neuron-like cell line), which express pituitary adenylate cyclase-activating polypeptide (PACAP) receptors linked to both adenylyl cyclase and phospholipase C-beta pathways, to investigate the influence of prolonged hormonal treatment on dual signaling and gene transcription. Prolonged incubation of cells with PACAP failed to down-regulate the density and affinity of membrane binding sites and caused opposite changes in messenger systems: PACAP-stimulated cyclic AMP accumulation was attenuated in a time- and dose-dependent fashion (t(1/2) = 6.7 h and IC50 = 0.1 nM), whereas phosphoinositide turnover was overstimulated. Both effects were insensitive to pertussis toxin, whereas the drop in cyclic AMP concentration was also unchanged in the presence of 3-isobutyl-1-methylxanthine, indicating that neither Gi-like proteins nor cyclic nucleotide phosphodiesterases play a critical role in these processes. Blockade of protein synthesis with cycloheximide, as well as inhibition by H89 of cyclic AMP-dependent protein kinase (but not by bisindolylmaleimide of protein kinase C) antagonized the influences exerted by PACAP on adenylyl cyclase activity and inositol phosphate formation. Transcription of the chimeric GAL4-CREB construct, transiently transfected into CATH.a cells, was stimulated by PACAP, and this effect was potentiated as a result of chronic PACAP treatment. The results of the present investigation provide new insight into the possible differential regulation and cross-talks of transduction signals of receptors linked to multiplex signaling. They demonstrate that prolonged exposure of CATH.a cells to PACAP results in the desensitization of the cyclic AMP pathway and superinduction of the inositol phosphate signal, through protein neosynthesis and cyclic AMP-dependent protein

O&P (Ova and Parasite) Test

MedlinePlus

... ova and parasite exam may be done in conjunction with or following a GI pathogens panel that ... infections, an O&P may be used in conjunction with other tests, such as a gastrointestinal (GI) ...

Cyclic AMP system in muscle tissue during prolonged hypokinesia

NASA Technical Reports Server (NTRS)

Antipenko, Y. A.; Bubeyev, Y. A.; Korovkin, B. F.; Mikhaleva, N. P.

1980-01-01

Components of the cyclic Adenosine-cyclic-35-monophosphate (AMP) system in the muscle tissue of white rats were studied during 70-75 days of hypokinesia, created by placing the animals in small booths which restricted their movements, and during the readaptation period. In the initial period, cyclic AMP levels and the activities of phosphodiesterase and adenylate cyclase in muscle tissue were increased. The values for these indices were roughly equal for controls and experimental animals during the adaptation period, but on the 70th day of the experiment cAMP levels dropped, phosphodiesterase activity increased, and the stimulative effect of epinephrine on the activity of adenylate cyclase decreased. The indices under study normalized during the readaptation period.

The cAMP analogs have potent anti-proliferative effects on medullary thyroid cancer cell lines.

PubMed

Dicitore, Alessandra; Grassi, Elisa Stellaria; Caraglia, Michele; Borghi, Maria Orietta; Gaudenzi, Germano; Hofland, Leo J; Persani, Luca; Vitale, Giovanni

2016-01-01

The oncogenic activation of the rearranged during transfection (RET) proto-oncogene has a main role in the pathogenesis of medullary thyroid cancer (MTC). Several lines of evidence suggest that RET function could be influenced by cyclic AMP (cAMP)-dependent protein kinase A (PKA) activity. We evaluated the in vitro anti-tumor activity of 8-chloroadenosine-3',5'-cyclic monophosphate (8-Cl-cAMP) and PKA type I-selective cAMP analogs [equimolar combination of the 8-piperidinoadenosine-3',5'-cyclic monophosphate (8-PIP-cAMP) and 8-hexylaminoadenosine-3',5'-cyclic monophosphate (8-HA-cAMP) in MTC cell lines (TT and MZ-CRC-1)]. 8-Cl-cAMP and the PKA I-selective cAMP analogs showed a potent anti-proliferative effect in both cell lines. In detail, 8-Cl-cAMP blocked significantly the transition of TT cell population from G2/M to G0/G1 phase and from G0/G1 to S phase and of MZ-CRC-1 cells from G0/G1 to S phase. Moreover, 8-Cl-cAMP induced apoptosis in both cell lines, as demonstrated by FACS analysis for annexin V-FITC/propidium iodide, the activation of caspase-3 and PARP cleavage. On the other hand, the only effect induced by PKA I-selective cAMP analogs was a delay in G0/G1-S and S-G2/M progression in TT and MZ-CRC-1 cells, respectively. In conclusion, these data demonstrate that cAMP analogs, particularly 8-Cl-cAMP, significantly suppress in vitro MTC proliferation and provide rationale for a potential clinical use of cAMP analogs in the treatment of advanced MTC.

Expert systems built by the Expert: An evaluation of OPS5

NASA Technical Reports Server (NTRS)

Jackson, Robert

1987-01-01

Two expert systems were written in OPS5 by the expert, a Ph.D. astronomer with no prior experience in artificial intelligence or expert systems, without the use of a knowledge engineer. The first system was built from scratch and uses 146 rules to check for duplication of scientific information within a pool of prospective observations. The second system was grafted onto another expert system and uses 149 additional rules to estimate the spacecraft and ground resources consumed by a set of prospective observations. The small vocabulary, the IF this occurs THEN do that logical structure of OPS5, and the ability to follow program execution allowed the expert to design and implement these systems with only the data structures and rules of another OPS5 system as an example. The modularity of the rules in OPS5 allowed the second system to modify the rulebase of the system onto which it was grafted without changing the code or the operation of that system. These experiences show that experts are able to develop their own expert systems due to the ease of programming and code reusability in OPS5.

Chronic exposure to organophosphate (OP) pesticides and neuropsychological functioning in farm workers: a review.

PubMed

Muñoz-Quezada, María Teresa; Lucero, Boris Andrés; Iglesias, Verónica Paz; Muñoz, María Pía; Cornejo, Claudia Alejandra; Achu, Eduardo; Baumert, Brittney; Hanchey, Arianna; Concha, Carlos; Brito, Ana María; Villalobos, Marcos

2016-01-01

Previous studies have demonstrated that acute poisoning from exposure to organophosphate (OP) pesticides in agricultural workers causes adverse health effects. However, neuropsychological and cognitive effects of chronic occupational exposure to OP pesticides remain controversial. To identify, evaluate, and systematize existing evidence regarding chronic exposure to OP pesticides and neuropsychological effects in farmworkers. Using the PubMed search engine, a systematic review process was implemented and replicated according to the PRISMA statement. Eligibility criteria included workers over 18 years of age exposed to OP pesticides as well as assessment of neuropsychological and cognitive functioning. Search terms were in English and Spanish languages and included organophosphate and workers. Of the search results, 33 of 1,256 articles meet eligibility criteria. Twenty-four studies found an association between chronic occupational exposure to OP pesticides and low neuropsychological performance in workers. We classified nine of the studies to have study design limitations. Studies indicated occupational exposure to OP pesticides is linked to difficulties in executive functions, psychomotor speed, verbal, memory, attention, processing speed, visual-spatial functioning, and coordination. Nine studies find no relationship between OP pesticides exposure and neuropsychological performance. Overall, evidence suggests an association between chronic occupational exposure to OP pesticides and neuropsychological effects. However, there is no consensus about the specific cognitive skills affected.

Impact of Nonoperating Periods on Equipment Reliability

DTIC Science & Technology

1985-05-01

capacitor nonoperating failure rate ./ Xnb = nonoperating base failure rate (failure/lO6 hours) =.0011, fixed paper/plastic film (CP, CZ, CA, CPV, CH , CHR...CPV, CH ,CHR,CQ,CQR,CFR,CRH) 2. Mica (CR,CM,CMR) 3. Glass (CY,CYR) 4. Ceramic (CC,CCR,CR,CRR) 5. Electrolytic (CE,CL,CLR,CSR,CU) 6. Fixed Vacuum or Gas...LM741 NSC DUAL OP AMP 237 BIPOLAR 0 0 .2815 .3869 . 7845 .9469 1.052 1.450 LM741 NSC OtwAL OP AMP 231 BIPOLAR 0 N .0180 .0322 .0647 .0501 .0900 .1806

cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharjee, Rajesh; Xiang, Wenpei; Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China

2012-06-22

Highlights: Black-Right-Pointing-Pointer cAMP blocks cell death induced by TNF and actinomycin D in cultured hepatocytes. Black-Right-Pointing-Pointer cAMP blocks NF-{kappa}B activation induced by TNF and actinomycin D. Black-Right-Pointing-Pointer cAMP blocks DISC formation following TNF and actinomycin D exposure. Black-Right-Pointing-Pointer cAMP blocks TNF signaling at a proximal step. -- Abstract: Tumor necrosis factor {alpha} (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1more » (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF + ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We

Cyclic AMP Affects Oocyte Maturation and Embryo Development in Prepubertal and Adult Cattle

PubMed Central

Bernal-Ulloa, Sandra Milena; Heinzmann, Julia; Herrmann, Doris; Hadeler, Klaus-Gerd; Aldag, Patrick; Winkler, Sylke; Pache, Dorit; Baulain, Ulrich; Lucas-Hahn, Andrea; Niemann, Heiner

2016-01-01

High cAMP levels during in vitro maturation (IVM) have been related to improved blastocyst yields. Here, we employed the cAMP/cGMP modulators, forskolin, IBMX, and cilostamide, during IVM to unravel the role of high cAMP in early embryonic development produced from prepubertal and adult bovine oocytes. Oocytes were collected via transvaginal aspiration and randomly assigned to three experimental groups: TCM24 (24h IVM/control), cAMP30 (2h pre-IVM (forskolin-IBMX), 30h IVM-cilostamide), and DMSO30 (Dimethyl Sulfoxide/vehicle control). After IVM, oocytes were fertilized in vitro and zygotes were cultured in vitro to blastocysts. Meiotic progression, cAMP levels, mRNA abundance of selected genes and DNA methylation were evaluated in oocytes. Blastocysts were used for gene expression or DNA methylation analyses. Blastocysts from the cAMP30 groups were transferred to recipients. The cAMP elevation delayed meiotic progression, but developmental rates were not increased. In immature oocytes, mRNA abundance of PRKACA was higher for cAMP30 protocol and no differences were found for PDE3A, SMAD2, ZAR1, PRDX1 and SLC2A8. EGR1 gene was up-regulated in prepubertal cAMP30 immature oocytes and down-regulated in blastocysts from all in vitro treatments. A similar gene expression profile was observed for DNMT3b, BCL2L1, PRDX1 and SLC2A8 in blastocysts. Satellite DNA methylation profiles were different between prepubertal and adult oocytes and blastocysts derived from the TCM24 and DMSO30 groups. Blastocysts obtained from prepubertal and adult oocytes in the cAMP30 treatment displayed normal methylation profiles and produced offspring. These data indicate that cAMP regulates IVM in prepubertal and adult oocytes in a similar manner, with impact on the establishment of epigenetic marks and acquisition of full developmental competency. PMID:26926596

AMP-Conjugated Quantum Dots: Low Immunotoxicity Both In Vitro and In Vivo

NASA Astrophysics Data System (ADS)

Dai, Tongcheng; Li, Na; Liu, Lu; Liu, Qin; Zhang, Yuanxing

2015-11-01

Quantum dots (QDs) are engineered nanoparticles that possess special optical and electronic properties and have shown great promise for future biomedical applications. In this work, adenosine 5'-monophosphate (AMP), a small biocompatible molecular, was conjugated to organic QDs to produce hydrophilic AMP-QDs. Using macrophage J774A.1 as the cell model, AMP-QDs exhibited both prior imaging property and low toxicity, and more importantly, triggered limited innate immune responses in macrophage, indicating low immunotoxicity in vitro. Using BALB/c mice as the animal model, AMP-QDs were found to be detained in immune organs but did not evoke robust inflammation responses or obvious histopathological abnormalities, which reveals low immunotoxicity in vivo. This work suggests that AMP is an excellent surface ligand with low immunotoxicity, and potentially used in surface modification for more extensive nanoparticles.

Embedded I&C for Extreme Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kisner, Roger A.

2016-04-01

This project uses embedded instrumentation and control (I&C) technologies to demonstrate potential performance gains of nuclear power plant components in extreme environments. Extreme environments include high temperature, radiation, high pressure, high vibration, and high EMI conditions. For extreme environments, performance gains arise from moment-to-moment sensing of local variables and immediate application of local feedback control. Planning for embedding I&C during early system design phases contrasts with the traditional, serial design approach that incorporates minimal I&C after mechanical and electrical design is complete. The demonstration application involves the development and control of a novel, proof-of-concept motor/pump design. The motor and pumpmore » combination operate within the fluid environment, eliminating the need for rotating seals. Actively controlled magnetic bearings also replace failure-prone mechanical contact bearings that typically suspend rotating components. Such as design has the potential to significantly enhance the reliability and life of the pumping system and would not be possible without embedded I&C.« less

Molecular Hydrogen Fluorescence in IC 63

NASA Technical Reports Server (NTRS)

Andersson, B-G

2005-01-01

This grant has supported the acquisition, reduction and analysis of data targeting the structure and excitation of molecular hydrogen in the reflection nebula IC 63 and in particular the fluorescent emission seen in the UV. In addition to manpower for analyzing the FUSE data, the grant supported the (attempted) acquisition of supporting ground-based data. We proposed for and received observing time for two sets of ground based, data; narrow band imaging ([S II], [O III) at KPNO (July 2002; Observer: Burgh) and imaging spectro-photometry of several of the near-infrared rotation-vibration lines of H2 at the IRTF (October 2003; Observer: Andersson). Unfortunately, both of these runs were failures, primarily because of bad weather, and did not result in any useful data. We combined the FUSE observations with rocket borne observations of the star responsible for exciting the H2 fluorescence in IC 63: gamma Cas, and with archival HUT observations of IC 63, covering the long-wavelength part of the molecular hydrogen fluorescence.

Inhibition of Rho Is Required for cAMP-induced Melanoma Cell Differentiation

PubMed Central

Buscà, Roser; Bertolotto, Corine; Abbe, Patricia; Englaro, Walter; Ishizaki, Toshimasa; Narumiya, Shuh; Boquet, Patrice; Ortonne, Jean-Paul; Ballotti, Robert

1998-01-01

Up-regulation of the cAMP pathway by forskolin or α-melanocyte stimulating hormone induces melanocyte and melanoma cell differentiation characterized by stimulation of melanin synthesis and dendrite development. Here we show that forskolin-induced dendricity is associated to a disassembly of actin stress fibers. Since Rho controls actin organization, we studied the role of this guanosine triphosphate (GTP)-binding protein in cAMP-induced dendrite formation. Clostridium botulinum C3 exotransferase, which inhibits Rho, mimicked the effect of forskolin in promoting dendricity and stress fiber disruption, while the Escherichia coli toxin cytotoxic necrotizing factor-1 (CNF-1), which activates Rho and the expression of a constitutively active Rho mutant, blocked forskolin-induced dendrite outgrowth. In addition, overexpression of a constitutively active form of the Rho target p160 Rho-kinase (P160ROCK) prevented the dendritogenic effects of cAMP. Our results suggest that inhibition of Rho and of its target p160ROCK are required events for cAMP-induced dendrite outgrowth in B16 cells. Furthermore, we present evidence that Rho is involved in the regulation of melanogenesis. Indeed, Rho inactivation enhanced the cAMP stimulation of tyrosinase gene transcription and protein expression, while Rho constitutive activation impaired these cAMP-induced effects. This reveals that, in addition to controlling dendricity, Rho also participates in the regulation of melanin synthesis by cAMP. PMID:9614180

New insight into the binding modes of TNP-AMP to human liver fructose-1,6-bisphosphatase

NASA Astrophysics Data System (ADS)

Han, Xinya; Huang, Yunyuan; Zhang, Rui; Xiao, San; Zhu, Shuaihuan; Qin, Nian; Hong, Zongqin; Wei, Lin; Feng, Jiangtao; Ren, Yanliang; Feng, Lingling; Wan, Jian

2016-08-01

Human liver fructose-1,6-bisphosphatase (FBPase) contains two binding sites, a substrate fructose-1,6-bisphosphate (FBP) active site and an adenosine monophosphate (AMP) allosteric site. The FBP active site works by stabilizing the FBPase, and the allosteric site impairs the activity of FBPase through its binding of a nonsubstrate molecule. The fluorescent AMP analogue, 2‧,3‧-O-(2,4,6-trinitrophenyl)adenosine 5‧-monophosphate (TNP-AMP) has been used as a fluorescent probe as it is able to competitively inhibit AMP binding to the AMP allosteric site and, therefore, could be used for exploring the binding modes of inhibitors targeted on the allosteric site. In this study, we have re-examined the binding modes of TNP-AMP to FBPase. However, our present enzyme kinetic assays show that AMP and FBP both can reduce the fluorescence from the bound TNP-AMP through competition for FBPase, suggesting that TNP-AMP binds not only to the AMP allosteric site but also to the FBP active site. Mutagenesis assays of K274L (located in the FBP active site) show that the residue K274 is very important for TNP-AMP to bind to the active site of FBPase. The results further prove that TNP-AMP is able to bind individually to the both sites. Our present study provides a new insight into the binding mechanism of TNP-AMP to the FBPase. The TNP-AMP fluorescent probe can be used to exam the binding site of an inhibitor (the active site or the allosteric site) using FBPase saturated by AMP and FBP, respectively, or the K247L mutant FBPase.

New insight into the binding modes of TNP-AMP to human liver fructose-1,6-bisphosphatase.

PubMed

Han, Xinya; Huang, Yunyuan; Zhang, Rui; Xiao, San; Zhu, Shuaihuan; Qin, Nian; Hong, Zongqin; Wei, Lin; Feng, Jiangtao; Ren, Yanliang; Feng, Lingling; Wan, Jian

2016-08-05

Human liver fructose-1,6-bisphosphatase (FBPase) contains two binding sites, a substrate fructose-1,6-bisphosphate (FBP) active site and an adenosine monophosphate (AMP) allosteric site. The FBP active site works by stabilizing the FBPase, and the allosteric site impairs the activity of FBPase through its binding of a nonsubstrate molecule. The fluorescent AMP analogue, 2',3'-O-(2,4,6-trinitrophenyl)adenosine 5'-monophosphate (TNP-AMP) has been used as a fluorescent probe as it is able to competitively inhibit AMP binding to the AMP allosteric site and, therefore, could be used for exploring the binding modes of inhibitors targeted on the allosteric site. In this study, we have re-examined the binding modes of TNP-AMP to FBPase. However, our present enzyme kinetic assays show that AMP and FBP both can reduce the fluorescence from the bound TNP-AMP through competition for FBPase, suggesting that TNP-AMP binds not only to the AMP allosteric site but also to the FBP active site. Mutagenesis assays of K274L (located in the FBP active site) show that the residue K274 is very important for TNP-AMP to bind to the active site of FBPase. The results further prove that TNP-AMP is able to bind individually to the both sites. Our present study provides a new insight into the binding mechanism of TNP-AMP to the FBPase. The TNP-AMP fluorescent probe can be used to exam the binding site of an inhibitor (the active site or the allosteric site) using FBPase saturated by AMP and FBP, respectively, or the K247L mutant FBPase. Copyright © 2016 Elsevier B.V. All rights reserved.

Chronic exposure to organophosphate (OP) pesticides and neuropsychological functioning in farm workers: a review

PubMed Central

Lucero, Boris Andrés; Iglesias, Verónica Paz; Muñoz, María Pía; Cornejo, Claudia Alejandra; Achu, Eduardo; Baumert, Brittney; Hanchey, Arianna; Concha, Carlos; Brito, Ana María; Villalobos, Marcos

2016-01-01

Background Previous studies have demonstrated that acute poisoning from exposure to organophosphate (OP) pesticides in agricultural workers causes adverse health effects. However, neuropsychological and cognitive effects of chronic occupational exposure to OP pesticides remain controversial. Objective To identify, evaluate, and systematize existing evidence regarding chronic exposure to OP pesticides and neuropsychological effects in farmworkers. Methods Using the PubMed search engine, a systematic review process was implemented and replicated according to the PRISMA statement. Eligibility criteria included workers over 18 years of age exposed to OP pesticides as well as assessment of neuropsychological and cognitive functioning. Search terms were in English and Spanish languages and included organophosphate and workers. Results Of the search results, 33 of 1,256 articles meet eligibility criteria. Twenty-four studies found an association between chronic occupational exposure to OP pesticides and low neuropsychological performance in workers. We classified nine of the studies to have study design limitations. Studies indicated occupational exposure to OP pesticides is linked to difficulties in executive functions, psychomotor speed, verbal, memory, attention, processing speed, visual–spatial functioning, and coordination. Nine studies find no relationship between OP pesticides exposure and neuropsychological performance. Conclusions Overall, evidence suggests an association between chronic occupational exposure to OP pesticides and neuropsychological effects. However, there is no consensus about the specific cognitive skills affected. PMID:27128815

cap alpha. /sub 2/-Adrenergic receptor-mediated sensitization of forskolin-stimulated cyclic AMP production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, S.B.; Toews, M.L.; Turner, J.T.

1987-03-01

Preincubation of HT29 human colonic adenocarcinoma cells with ..cap alpha../sub 2/-adrenergic agonists resulted in a 10- to 20-fold increase in forskolin-stimulated cyclic AMP production as compared to cells preincubated without agonist. Similar results were obtained using either a (/sup 3/H)adenine prelabeling assay or a cyclic AMP radioimmunoassay to measure cyclic AMP levels. This phenomenon, which is termed sensitization, is ..cap alpha../sub 2/-adrenergic receptor-mediated and rapid in onset and reversal. Yohimbine, an ..cap alpha../sub 2/-adrenergic receptor-selective antagonist, blocked norepinephrine-induced sensitization, whereas prazosin (..cap alpha../sub 1/-adrenergic) and sotalol (..beta..-adrenergic) did not. The time for half-maximal sensitization was 5 min and the half-timemore » for reversal was 10 min. Only a 2-fold sensitization of cyclic AMP production stimulated by vasoactive intestinal peptide was observed, indicating that sensitization is relatively selective for forskolin. Sensitization reflects an increased production of cyclic AMP and not a decreased degradation of cyclic AMP, since incubation with a phosphodiesterase inhibitor and forskolin did not mimic sensitization. Increasing the levels of cyclic AMP during the preincubation had no effect on sensitization, indicating that sensitization is not caused by decreased cyclic AMP levels during the preincubation. This rapid and dramatic sensitization of forskolin-stimulated cyclic AMP production is a previously unreported effect that can be added to the growing list of ..cap alpha../sub 2/-adrenergic responses that are not mediated by a decrease in cyclic AMP.« less

Covariant symplectic structure of the complex Monge-Ampère equation

NASA Astrophysics Data System (ADS)

Nutku, Y.

2000-04-01

The complex Monge-Ampère equation is invariant under arbitrary holomorphic changes of the independent variables with unit Jacobian. We present its variational formulation where the action remains invariant under this infinite group. The new Lagrangian enables us to obtain the first symplectic 2-form for the complex Monge-Ampère equation in the framework of the covariant Witten-Zuckerman approach to symplectic structure. We base our considerations on a reformulation of the Witten-Zuckerman theory in terms of holomorphic differential forms. The first closed and conserved Witten-Zuckerman symplectic 2-form for the complex Monge-Ampère equation is obtained in arbitrary dimension and for all cases elliptic, hyperbolic and homogeneous. The connection of the complex Monge-Ampère equation with Ricci-flat Kähler geometry suggests the use of the Hilbert action principle as an alternative variational formulation. However, we point out that Hilbert's Lagrangian is a divergence for Kähler metrics and serves as a topological invariant rather than yielding the Euclideanized Einstein field equations. Nevertheless, since the Witten-Zuckerman theory employs only the boundary terms in the first variation of the action, Hilbert's Lagrangian can be used to obtain the second Witten-Zuckerman symplectic 2-form. This symplectic 2-form vanishes on shell, thus defining a Lagrangian submanifold. In its derivation the connection of the second symplectic 2-form with the complex Monge-Ampère equation is indirect but we show that it satisfies all the properties required of a symplectic 2-form for the complex elliptic, or hyperbolic Monge-Ampère equation when the dimension of the complex manifold is 3 or higher. The complex Monge-Ampère equation admits covariant bisymplectic structure for complex dimension 3, or higher. However, in the physically interesting case of n=2 we have only one symplectic 2-form. The extension of these results to the case of complex Monge-Amp

H I debris in the IC 1459 galaxy group

NASA Astrophysics Data System (ADS)

Saponara, Juliana; Koribalski, Bärbel S.; Benaglia, Paula; Fernández López, Manuel

2018-01-01

We present H I synthesis imaging of the giant elliptical galaxy IC 1459 and its surroundings with the Australia Telescope Compact Array. Our search for extended H I emission revealed a large complex of H I clouds near IC 1459, likely to be the debris from tidal interactions with neighbouring galaxies. The total H I mass (∼109 M⊙) in the detected clouds spans 250 kpc from the north-east of the gas-rich spiral NGC 7418A to the south-east of IC 1459. The extent and mass of the H I debris, which shows rather irregular morphology and kinematics, are similar to those in other nearby groups. Together with H I clouds recently detected near two other IC 1459 group members, namely IC 5270 and NGC 7418, using phased-array feeds on the Australian Square Kilometre Array Pathfinder, the detected debris make up a significant fraction of the group's intergalactic medium.

Dual contradictory roles of cAMP signaling pathways in hydroxyl radical production in the rat striatum.

PubMed

Hara, Shuichi; Kobayashi, Masamune; Kuriiwa, Fumi; Mukai, Toshiji; Mizukami, Hajime

2012-03-15

Studies have suggested that cAMP signaling pathways may be associated with the production of reactive oxygen species. In this study, we examined how modifications in cAMP signaling affected the production of hydroxyl radicals in rat striatum using microdialysis to measure extracellular 2,3-dihydroxybenzoic acid (2,3-DHBA), which is a hydroxyl radical adduct of salicylate. Up to 50 nmol of the cell-permeative cAMP mimetic 8-bromo-cAMP (8-Br-cAMP) increased 2,3-DHBA in a dose-dependent manner (there was no additional increase in 2,3-DHBA at 100 nmol). Another cAMP mimetic, dibutyryl cAMP (db-cAMP), caused a nonsignificant increase in 2,3-DHBA at 50 nmol and a significant decrease at 100 nmol. Up to 20 nmol of forskolin, which is a direct activator of adenylyl cyclase, increased 2,3-DHBA, similar to the effect of 8-Br-cAMP; however, forskolin resulted in a much greater increase in 2,3-DHBA. A potent inhibitor of protein kinase A (PKA), H89 (500 μM), potentiated the 8-Br-cAMP- and forskolin-induced increases in 2,3-DHBA and antagonized the inhibitory effect of 100 nmol of db-cAMP. Interestingly, the administration of 100 nmol of 8-bromo-cGMP alone or in combination with H89 had no significant effect on 2,3-DHBA levels. Doses of 100 nmol of a preferential PKA activator (6-phenyl-cAMP) or a preferential PKA inhibitor (8-bromoadenosine-3',5'-cyclic monophosphorothionate, Rp-isomer; Rp-8-Br-cAMPS), which also inhibits the cAMP-mediated activation of Epac (the exchange protein directly activated by cAMP), suppressed or enhanced, respectively, the formation of 2,3-DHBA. Up to 100 nmol of 8-(4-chlorophenylthio)-2'-O-methyladenosine-cAMP, which is a selective activator of Epac, dose-dependently stimulated the formation of 2,3-DHBA. These findings suggest that cAMP signaling plays contradictory roles (stimulation and inhibition) in the production of hydroxyl radicals in rat striatum by differential actions of Epac and PKA. These roles might contribute to the production of

Cardiac Hypertrophy Is Inhibited by a Local Pool of cAMP Regulated by Phosphodiesterase 2.

PubMed

Zoccarato, Anna; Surdo, Nicoletta C; Aronsen, Jan M; Fields, Laura A; Mancuso, Luisa; Dodoni, Giuliano; Stangherlin, Alessandra; Livie, Craig; Jiang, He; Sin, Yuan Yan; Gesellchen, Frank; Terrin, Anna; Baillie, George S; Nicklin, Stuart A; Graham, Delyth; Szabo-Fresnais, Nicolas; Krall, Judith; Vandeput, Fabrice; Movsesian, Matthew; Furlan, Leonardo; Corsetti, Veronica; Hamilton, Graham; Lefkimmiatis, Konstantinos; Sjaastad, Ivar; Zaccolo, Manuela

2015-09-25

Chronic elevation of 3'-5'-cyclic adenosine monophosphate (cAMP) levels has been associated with cardiac remodeling and cardiac hypertrophy. However, enhancement of particular aspects of cAMP/protein kinase A signaling seems to be beneficial for the failing heart. cAMP is a pleiotropic second messenger with the ability to generate multiple functional outcomes in response to different extracellular stimuli with strict fidelity, a feature that relies on the spatial segregation of the cAMP pathway components in signaling microdomains. How individual cAMP microdomains affect cardiac pathophysiology remains largely to be established. The cAMP-degrading enzymes phosphodiesterases (PDEs) play a key role in shaping local changes in cAMP. Here we investigated the effect of specific inhibition of selected PDEs on cardiac myocyte hypertrophic growth. Using pharmacological and genetic manipulation of PDE activity, we found that the rise in cAMP resulting from inhibition of PDE3 and PDE4 induces hypertrophy, whereas increasing cAMP levels via PDE2 inhibition is antihypertrophic. By real-time imaging of cAMP levels in intact myocytes and selective displacement of protein kinase A isoforms, we demonstrate that the antihypertrophic effect of PDE2 inhibition involves the generation of a local pool of cAMP and activation of a protein kinase A type II subset, leading to phosphorylation of the nuclear factor of activated T cells. Different cAMP pools have opposing effects on cardiac myocyte cell size. PDE2 emerges as a novel key regulator of cardiac hypertrophy in vitro and in vivo, and its inhibition may have therapeutic applications. © 2015 American Heart Association, Inc.

Metabolic benefits of inhibiting cAMP-PDEs with resveratrol.

PubMed

Chung, Jay H

2012-10-01

Calorie restriction (CR) extends lifespan in species ranging from yeast to mammals. There is evidence that CR also protects against aging-related diseases in non-human primates. This has led to an intense interest in the development of CR-mimetics to harness the beneficial effects of CR to treat aging-related diseases. One CR-mimetic that has received a great deal of attention is resveratrol. Resveratrol extends the lifespan of obese mice and protects against obesity-related diseases such as type 2 diabetes. The specific mechanism of resveratrol action has been difficult to elucidate because resveratrol has a promiscuous target profile. A recent finding indicates that the metabolic effects of resveratrol may result from competitive inhibition of cAMP-degrading phosphodiesterases (PDEs), which increases cAMP levels. The cAMP-dependent pathways activate AMP-activated protein kinase (AMPK), which is essential for the metabolic effects of resveratrol. Inhibiting PDE4 with rolipram reproduces all of the metabolic benefits of resveratrol, including protection against diet-induced obesity and an increase in mitochondrial function, physical stamina and glucose tolerance in mice. This discovery suggests that PDE inhibitors may be useful for treating metabolic diseases associated with aging.

Saturn V S-IC (First) Stage

NASA Technical Reports Server (NTRS)

2004-01-01

This cutaway illustration shows the Saturn V S-IC (first) stage with detailed callouts of the components. The S-IC Stage is 138 feet long and 33 feet in diameter, producing 7,500,000 pounds of thrust through five F-1 engines that are powered by liquid oxygen and kerosene. Four of the engines are mounted on an outer ring and gimbal for control purposes. The fifth engine is rigidly mounted in the center. When ignited, the roar produced by the five engines equals the sound of 8,000,000 hi-fi sets.

Role of 2',3'-cyclic nucleotide 3'-phosphodiesterase in the renal 2',3'-cAMP-adenosine pathway.

PubMed

Jackson, Edwin K; Gillespie, Delbert G; Mi, Zaichuan; Cheng, Dongmei; Bansal, Rashmi; Janesko-Feldman, Keri; Kochanek, Patrick M

2014-07-01

Energy depletion increases the renal production of 2',3'-cAMP (a positional isomer of 3',5'-cAMP that opens mitochondrial permeability transition pores) and 2',3'-cAMP is converted to 2'-AMP and 3'-AMP, which in turn are metabolized to adenosine. Because the enzymes involved in this "2',3'-cAMP-adenosine pathway" are unknown, we examined whether 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) participates in the renal metabolism of 2',3'-cAMP. Western blotting and real-time PCR demonstrated expression of CNPase in rat glomerular mesangial, preglomerular vascular smooth muscle and endothelial, proximal tubular, thick ascending limb and collecting duct cells. Real-time PCR established the expression of CNPase in human glomerular mesangial, proximal tubular and vascular smooth muscle cells; and the level of expression of CNPase was greater than that for phosphodiesterase 4 (major enzyme for the metabolism of 3',5'-cAMP). Overexpression of CNPase in rat preglomerular vascular smooth muscle cells increased the metabolism of exogenous 2',3'-cAMP to 2'-AMP. Infusions of 2',3'-cAMP into isolated CNPase wild-type (+/+) kidneys increased renal venous 2'-AMP, and this response was diminished by 63% in CNPase knockout (-/-) kidneys, whereas the conversion of 3',5'-cAMP to 5'-AMP was similar in CNPase +/+ vs. -/- kidneys. In CNPase +/+ kidneys, energy depletion (metabolic poisons) increased kidney tissue levels of adenosine and its metabolites (inosine, hypoxanthine, xanthine, and uric acid) without accumulation of 2',3'-cAMP. In contrast, in CNPase -/- kidneys, energy depletion increased kidney tissue levels of 2',3'-cAMP and abolished the increase in adenosine and its metabolites. In conclusion, kidneys express CNPase, and renal CNPase mediates in part the renal 2',3'-cAMP-adenosine pathway. Copyright © 2014 the American Physiological Society.

Aerobic Methane Generation From Plants (AMP)? Yes, Mostly!

NASA Astrophysics Data System (ADS)

Whiticar, M. J.; Ednie, A. C.

2007-12-01

In 2006, Keppler et al. (K) published an intriguing and revolutionary idea that aerobic methane is produced in plants (AMP) and released to the atmosphere. Their initial scaling calculations estimated the amount of AMP fluxing from living plants to range from 62-236 Tg/y and 1-7 Tg/y for plant litter. Houweling et al. (2006) (H) refined this flux to ca. 85 Tg/y PIH and 125 Tg/y present day. More recently, Dueck et al. (2007) (D) challenged the claim of AMP from intact plants. Their experiments cited "...No evidence for substantial aerobic methane emission by terrestrial plants..." (max. 0.4 ng/g h-1). Due to the significance of AMP in understanding present and palaeo-atmospheric budgets (e.g., Whiticar and Schaefer, 2007), we conducted a wide range of experiments to confirm or refute the existence and magnitude of AMP. For explanation, experiments of K were time-series batch samples measured by gas chromatography on purged and ambient samples, whereas D used continuous-flow cuvettes and measured by optical PAS with time series single injections. Our longer-term experiments with corn, wheat, tomato, red cedar, chestnut, moss and lichen (3-97 h, 32 °C) used a plant chamber, flow-through system with a GYRO, an optical spectrometer that enables continuous 1 Hz CH4 measurements with a precision of ca. 1 ppbv. We conducted over 100 chamber experiments on sterilized and non-sterilized (Cs-137 radiation) samples of: 1) intact living plants (IP), 2) fresh leaves (FL) and 3) dried leaves (DL); under both 1) high and 2) low light conditions (HL, LL), and with 1) ambient CH4 (AM, ca. 1.92 ppmv) and 2) purged methane (PM, 10 and 96 ppbv) levels. Our results demonstrate that IP-AMs have CH4 flux rates of 0.74-3.48 ng/g h-1. In contrast, IP-PMs show intense CH4 uptake rates of -28.5 to -57.9 ng/g h-1 (substantially different than K's reported emissions of 12-370 ng/g h-1 values). Our FL-AM-LL have CH4 flux rates of 0.36-2.05 ng/g h-1, whereas FL-AM-HL have significant CH4

Proliferation kinetics and cyclic AMP as prognostic factors in adult acute leukemia.

PubMed

Paietta, E; Mittermayer, K; Schwarzmeier, J

1980-07-01

In 41 adult patients with acute leukemia (myeloblastic, lymphoblastic, and undifferentiated), proliferation kinetics (as determined by double-label autoradiography) and cyclic adenosine 3',5'-monophosphate (cAMP) concentration were studied for their significance in the prediction of responsiveness to cytostatic therapy. Patients with good clinical response had significantly shorter turnover times and higher labeling indices in the bone marrow than did those who failed to respond to treatment. Cases for which cell kinetics did not correlate with clinical response were explained by variance in the distribution of leukemic blasts between the proliferative cell cycle and the resting pool. Good clinical response was also found to be associated with low levels of cAMP in leukemic cells prior to therapy, whereas high cAMP contents predicted failure. Low cAMP concentrations, however, did not necessarily correlate with short turnover times and vice versa. This might be due to fluctuations of the cAMP concentrations during the cell cycle.

Improved cell disruption of Pichia pastoris utilizing aminopropyl magnesium phyllosilicate (AMP) clay.

PubMed

Kim, Sun-Il; Wu, Yuanzheng; Kim, Ka-Lyun; Kim, Geun-Joong; Shin, Hyun-Jae

2013-06-01

An efficient method for Pichia cell disruption that employs an aminopropyl magnesium phyllosilicate (AMP) clay-assisted glass beads mill is presented. AMP clay is functionalized nanocomposite resembling the talc parent structure Si8Mg6O20(OH)4 that has been proven to permeate the bacterial membrane and cause cell lysis. The recombinant capsid protein of cowpea chlorotic mottle virus (CCMV) expressed in Pichia pastoris GS115 was used as demonstration system for their ability of self-assembly into icosahedral virus-like particles (VLPs). The total protein concentration reached 4.24 mg/ml after 4 min treatment by glass beads mill combined with 0.2 % AMP clay, which was 11.2 % higher compared to glass beads mill only and the time was half shortened. The stability of purified CCMV VLPs illustrated AMP clay had no influence on virus assembly process. Considering the tiny amount added and simple approach of AMP clay, it could be a reliable method for yeast cell disruption.

Microwave assisted coating of bioactive amorphous magnesium phosphate (AMP) on polyetheretherketone (PEEK).

PubMed

Ren, Yufu; Sikder, Prabaha; Lin, Boren; Bhaduri, Sarit B

2018-04-01

Polyetheretherketone (PEEK) with great thermal and chemical stability, desirable mechanical properties and promising biocompatibility is being widely used as orthopedic and dental implant materials. However, the bioinert surface of PEEK can hinder direct osseointegration between the host tissue and PEEK based implants. The important signatures of this paper are as follows. First, we report for the formation of osseointegrable amorphous magnesium phosphate (AMP) coating on PEEK surface using microwave energy. Second, coatings consist of nano-sized AMP particles with a stacked thickness of 800nm. Third, coatings enhance bioactivity in-vitro and induce significantly high amount of bone-like apatite coating, when soaked in simulated body fluid (SBF). Fourth, the as-deposited AMP coatings present no cytotoxicity effects and are beneficial for cell adhesion at early stage. Finally, the high levels of expression of osteocalcin (OCN) in cells cultured on AMP coated PEEK samples indicate that AMP coatings can promote new bone formation and hence osseointegration. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of ventral striatal cAMP signaling in stress-induced behaviors

PubMed Central

Plattner, Florian; Hayashi, Kanehiro; Hernandez, Adan; Benavides, David R.; Tassin, Tara C.; Tan, Chunfeng; Day, Jonathan; Fina, Maggy W.; Yuen, Eunice Y.; Yan, Zhen; Goldberg, Matthew S.; Nairn, Angus C.; Greengard, Paul; Nestler, Eric J.; Taussig, Ronald; Nishi, Akinori; Houslay, Miles D.; Bibb, James A.

2015-01-01

The cAMP/PKA signaling cascade is a ubiquitous pathway acting downstream of multiple neuromodulators. We found that the phosphorylation of phosphodiesterase-4 (PDE4) by cyclin-dependent protein kinase 5 (Cdk5) facilitates cAMP degradation and homeostasis of cAMP/PKA signaling. In mice, loss of Cdk5 throughout the forebrain elevated cAMP levels and increased PKA activity in striatal neurons, and altered behavioral responses to acute or chronic stressors. Ventral striatum- or D1 dopamine receptor-specific conditional knockout of Cdk5, or ventral striatum infusion of a small interfering peptide that selectively targets the regulation of PDE4 by Cdk5, all produced analogical effects on stress-induced behavioral responses. Together, our results demonstrate that altering cAMP signaling in medium spiny neurons of the ventral striatum can effectively modulate stress-induced behavioral states. We propose that targeting the Cdk5 regulation of PDE4 could be a new therapeutic approach for clinical conditions associated with stress, such as depression. PMID:26192746

Dibutyryl cAMP effects on thromboxane and leukotriene production in decompression-induced lung injury

NASA Technical Reports Server (NTRS)

Little, T. M.; Butler, B. D.

1997-01-01

Decompression-induced venous bubble formation has been linked to increased neutrophil counts, endothelial cell injury, release of vasoactive eicosanoids, and increased vascular membrane permeability. These actions may account for inflammatory responses and edema formation. Increasing the intracellular cAMP has been shown to decrease eicosanoid production and edema formation in various models of lung injury. Reduction of decompression-induced inflammatory responses was evaluated in decompressed rats pretreated with saline (controls) or dibutyryl cAMP (DBcAMP, an analog of cAMP). After pretreatment, rats were exposed to either 616 kPa for 120 min or 683 kPa for 60 min. The observed increases in extravascular lung water ratios (pulmonary edema), bronchoalveolar lavage, and pleural protein in the saline control group (683 kPa) were not evident with DBcAMP treatment. DBcAMP pretreatment effects were also seen with the white blood cell counts and the percent of neutrophils in the bronchoalveolar lavage. Urinary levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were significantly increased with the 683 kPa saline control decompression exposure. DBcAMP reduced the decompression-induced leukotriene E4 production in the urine. Plasma levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were increased with the 683-kPa exposure groups. DBcAMP treatment did not affect these changes. The 11-dehydrothromboxane B2 and leukotriene E4 levels in the bronchoalveolar lavage were increased with the 683 kPa exposure and were reduced with the DBcAMP treatment. Our results indicate that DBcAMP has the capability to reduce eicosanoid production and limit membrane permeability and subsequent edema formation in rats experiencing decompression sickness.

Temporal Analysis of the Magnaporthe Oryzae Proteome During Conidial Germination and Cyclic AMP (cAMP)-mediated Appressorium Formation*

PubMed Central

Franck, William L.; Gokce, Emine; Oh, Yeonyee; Muddiman, David C.; Dean, Ralph A.

2013-01-01

Rice blast disease caused by Magnaporthe oryzae is one of the most serious threats to global rice production. During the earliest stages of rice infection, M. oryzae conidia germinate on the leaf surface and form a specialized infection structure termed the appressorium. The development of the appressorium represents the first critical stage of infectious development. A total of 3200 unique proteins were identified by nanoLC-MS/MS in a temporal study of conidial germination and cAMP-induced appressorium formation in M. oryzae. Using spectral counting based label free quantification, observed changes in relative protein abundance during the developmental process revealed changes in the cell wall biosynthetic machinery, transport functions, and production of extracellular proteins in developing appressoria. One hundred and sixty-six up-regulated and 208 down-regulated proteins were identified in response to cAMP treatment. Proteomic analysis of a cAMP-dependent protein kinase A mutant that is compromised in the ability to form appressoria identified proteins whose developmental regulation is dependent on cAMP signaling. Selected reaction monitoring was used for absolute quantification of four regulated proteins to validate the global proteomics data and confirmed the germination or appressorium specific regulation of these proteins. Finally, a comparison of the proteome and transcriptome was performed and revealed little correlation between transcript and protein regulation. A subset of regulated proteins were identified whose transcripts show similar regulation patterns and include many of the most strongly regulated proteins indicating a central role in appressorium formation. A temporal quantitative RT-PCR analysis confirmed a strong correlation between transcript and protein abundance for some but not all genes. Collectively, the data presented here provide the first comprehensive view of the M. oryzae proteome during early infection-related development and

Evaluation of uridine 5'-eicosylphosphate as a stimulant of cyclic AMP-dependent cellular function.

PubMed

Yutani, Masahiro; Ogita, Akira; Fujita, Ken-Ichi; Usuki, Yoshinosuke; Tanaka, Toshio

2011-03-01

Sporulation of the yeast Saccharomyces cerevisiae is negatively regulated by cyclic AMP (cAMP). This microbial cell differentiation process was applied for the screening of a substance that can elevate the intracellular cAMP level. Among nucleoside 5'-alkylphosphates, uridine 5'-eicosylphosphate (UMPC20) selectively and predominantly inhibited ascospore formation of the yeast cells. We suppose the inhibitory effect of UMPC20 could indeed reflect the elevation of the cellular cAMP level.

Op art and visual perception.

PubMed

Wade, N J

1978-01-01

An attempt is made to list the visual phenomena exploited in op art. These include moire frinlude moiré fringes, afterimages, Hermann grid effects, Gestalt grouping principles, blurring and movement due to astigmatic fluctuations in accommodation, scintillation and streaming possibly due to eye movements, and visual persistence. The historical origins of these phenomena are also noted.

Therapeutic effects of OP-1 on metal wear particle induced osteoblasts injury in vitro

PubMed Central

Sun, Guojing; Chen, Jianmin; Yang, Shufeng; Parker, Thomas MN; Goodman, Gary MP; Hasama, Jack M; Zhao, Jianning

2015-01-01

Aseptic lossening is a main reason for the revision of total joint arthroplasty. Metal-wear particles induced deregulation of bone resorption or formation has been considered as the major process of aseptic lossening. Osteogenic protein-1 (OP-1) can be used to improve bone formation. However, such effect is not clearly understood after the metal-wear particles injury. Here, we investigated the molecular mechanisms by which OP-1 regulates the activity of bone formation and anti-inflammatory after injury. Results showed that OP-1 increased cell viability and bone formation ability of impaired osteoblast cells at 72 hours after being injured by cobalt particles. Pathway analyses revealed that both mRNA and protein levels of Smad1 and Smad5 were significantly increased upon the treatment of OP-1 in the cell injury model. Similarly, runt-related transcription factor 2 (Runx2) was also significantly upregulated in the OP-1 treated cells. Moreover, treatment with OP-1 inhibited the secretion of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-18 in cobalt impaired cells. Collectively, these results suggest that OP-1 could inhibit cobalt particles induced cell injury by activating Smad1, Smad5, and Runx2, and such procedure is accompanied by anti-inflammatory reaction. PMID:26885192

Constitutional abnormalities of chromosome 21 predispose to iAMP21-acute lymphoblastic leukaemia.

PubMed

Harrison, Christine J; Schwab, Claire

2016-03-01

In addition to Down syndrome, individuals with other constitutional abnormalities of chromosome 21 have an increased risk of developing childhood acute lymphoblastic leukaemia (ALL). Specifically, carriers of the Robertsonian translocation between chromosomes 15 and 21, rob(15;21) (q10; q10)c, have ∼2,700 increased risk of developing ALL with iAMP21 (intrachromosomal amplification of chromosome 21). In these patients, chromosome 15 as well as chromosome 21 is involved in the formation of iAMP21, referred to here as der(21)(15;21). Individuals with constitutional ring chromosomes involving chromosome 21, r(21)c, are also predisposed to iAMP21-ALL, involving the same series of mutational processes as seen in sporadic- and der(21)(15;21)-iAMP21 ALL. Evidence is accumulating that the dicentric nature of the Robertsonian and ring chromosome is the initiating factor in the formation of the complex iAMP21 structure. Unravelling these intriguing predispositions to iAMP21-ALL may provide insight into how other complex rearrangements arise in cancer. Copyright © 2016. Published by Elsevier Masson SAS.

CMOS image sensor with contour enhancement

NASA Astrophysics Data System (ADS)

Meng, Liya; Lai, Xiaofeng; Chen, Kun; Yuan, Xianghui

2010-10-01

Imitating the signal acquisition and processing of vertebrate retina, a CMOS image sensor with bionic pre-processing circuit is designed. Integration of signal-process circuit on-chip can reduce the requirement of bandwidth and precision of the subsequent interface circuit, and simplify the design of the computer-vision system. This signal pre-processing circuit consists of adaptive photoreceptor, spatial filtering resistive network and Op-Amp calculation circuit. The adaptive photoreceptor unit with a dynamic range of approximately 100 dB has a good self-adaptability for the transient changes in light intensity instead of intensity level itself. Spatial low-pass filtering resistive network used to mimic the function of horizontal cell, is composed of the horizontal resistor (HRES) circuit and OTA (Operational Transconductance Amplifier) circuit. HRES circuit, imitating dendrite of the neuron cell, comprises of two series MOS transistors operated in weak inversion region. Appending two diode-connected n-channel transistors to a simple transconductance amplifier forms the OTA Op-Amp circuit, which provides stable bias voltage for the gate of MOS transistors in HRES circuit, while serves as an OTA voltage follower to provide input voltage for the network nodes. The Op-Amp calculation circuit with a simple two-stage Op-Amp achieves the image contour enhancing. By adjusting the bias voltage of the resistive network, the smoothing effect can be tuned to change the effect of image's contour enhancement. Simulations of cell circuit and 16×16 2D circuit array are implemented using CSMC 0.5μm DPTM CMOS process.

Extracellular 2′,3′-cAMP-adenosine pathway in proximal tubular, thick ascending limb, and collecting duct epithelial cells

PubMed Central

Gillespie, Delbert G.

2013-01-01

In a previous study, we demonstrated that human proximal tubular epithelial cells obtained from a commercial source metabolized extracellular 2′,3′-cAMP to 2′-AMP and 3′-AMP and extracellular 2′-AMP and 3′-AMP to adenosine (the extracellular 2′,3′-cAMP-adenosine pathway; extracellular 2′,3′-cAMP → 2′-AMP + 3′-AMP → adenosine). The purpose of this study was to investigate the metabolism of extracellular 2′,3′-cAMP in proximal tubular vs. thick ascending limb vs. collecting duct epithelial cells freshly isolated from their corresponding nephron segments obtained from rat kidneys. In epithelial cells from all three nephron segments, 1) extracellular 2′,3′-cAMP was metabolized to 2′-AMP and 3′-AMP, with 2′-AMP > 3′-AMP, 2) the metabolism of extracellular 2′,3′-cAMP to 2′-AMP and 3′-AMP was not inhibited by either 3-isobutyl-1-methylxanthine (phosphodiesterase inhibitor) or 1,3-dipropyl-8-p-sulfophenylxanthine (ecto-phosphodiesterase inhibitor), 3) extracellular 2′,3′-cAMP increased extracellular adenosine levels, 4) 3′-AMP and 2′-AMP were metabolized to adenosine with an efficiency similar to that of 5′-AMP, and 5) the metabolism of 5′-AMP, 3′-AMP, and 2′-AMP was not inhibited by α,β-methylene-adenosine-5′-diphosphate (CD73 inhibitor). These results support the conclusion that renal epithelial cells all along the nephron can metabolize extracellular 2′,3′-cAMP to 2′-AMP and 3′-AMP and can efficiently metabolize extracellular 2′-AMP and 3′-AMP to adenosine and that the metabolic enzymes involved are not the classical phosphodiesterases nor ecto-5′-nucleotidase (CD73). Because 2′,3′-cAMP is released by injury and because previous studies demonstrate that the extracellular 2′,3′-cAMP-adenosine pathway stimulates epithelial cell proliferation via adenosine A2B receptors, the present results suggest that the extracellular 2′,3′-cAMP-adenosine pathway may help restore epithelial

Absorption performance for CO2 capture process using MDEA-AMP aqueous solution

NASA Astrophysics Data System (ADS)

Liu, Gang; Kou, Liqing; Li, Chao

2017-03-01

The absorption capacity and the absorption rate of CO2 in 2-amino-2-methyl-1-propanol (AMP)-N-methyldiethanolamine (MDEA) aqueous solution were measured. The temperatures ranged from 303.2K to 323.2K. The mass fractions of AMP and MDEA respectively ranged from 0 to 0.03 and 0.2 to 0.3. The influence of temperature and w AMP on the absorption capacity and absorption rate of CO2 was illustrated.

modlAMP: Python for antimicrobial peptides.

PubMed

Müller, Alex T; Gabernet, Gisela; Hiss, Jan A; Schneider, Gisbert

2017-09-01

We have implemented the lecular esign aboratory's nti icrobial eptides package ( ), a Python-based software package for the design, classification and visual representation of peptide data. modlAMP offers functions for molecular descriptor calculation and the retrieval of amino acid sequences from public or local sequence databases, and provides instant access to precompiled datasets for machine learning. The package also contains methods for the analysis and representation of circular dichroism spectra. The modlAMP Python package is available under the BSD license from URL http://doi.org/10.5905/ethz-1007-72 or via pip from the Python Package Index (PyPI). gisbert.schneider@pharma.ethz.ch. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Isolation of novel ribozymes that ligate AMP-activated RNA substrates

NASA Technical Reports Server (NTRS)

Hager, A. J.; Szostak, J. W.

1997-01-01

BACKGROUND: The protein enzymes RNA ligase and DNA ligase catalyze the ligation of nucleic acids via an adenosine-5'-5'-pyrophosphate 'capped' RNA or DNA intermediate. The activation of nucleic acid substrates by adenosine 5'-monophosphate (AMP) may be a vestige of 'RNA world' catalysis. AMP-activated ligation seems ideally suited for catalysis by ribozymes (RNA enzymes), because an RNA motif capable of tightly and specifically binding AMP has previously been isolated. RESULTS: We used in vitro selection and directed evolution to explore the ability of ribozymes to catalyze the template-directed ligation of AMP-activated RNAs. We subjected a pool of 10(15) RNA molecules, each consisting of long random sequences flanking a mutagenized adenosine triphosphate (ATP) aptamer, to ten rounds of in vitro selection, including three rounds involving mutagenic polymerase chain reaction. Selection was for the ligation of an oligonucleotide to the 5'-capped active pool RNA species. Many different ligase ribozymes were isolated; these ribozymes had rates of reaction up to 0.4 ligations per hour, corresponding to rate accelerations of approximately 5 x10(5) over the templated, but otherwise uncatalyzed, background reaction rate. Three characterized ribozymes catalyzed the formation of 3'-5'-phosphodiester bonds and were highly specific for activation by AMP at the ligation site. CONCLUSIONS: The existence of a new class of ligase ribozymes is consistent with the hypothesis that the unusual mechanism of the biological ligases resulted from a conservation of mechanism during an evolutionary replacement of a primordial ribozyme ligase by a more modern protein enzyme. The newly isolated ligase ribozymes may also provide a starting point for the isolation of ribozymes that catalyze the polymerization of AMP-activated oligonucleotides or mononucleotides, which might have been the prebiotic analogs of nucleoside triphosphates.

Inhibition of AMP deaminase as therapeutic target in cardiovascular pathology.

PubMed

Zabielska, Magdalena A; Borkowski, Tomasz; Slominska, Ewa M; Smolenski, Ryszard T

2015-08-01

AMP deaminase (AMPD; EC 3.5.4.6) catalyzes hydrolysis of the amino group from the adenine ring of AMP resulting in production of inosine 5'-monophosphate (IMP) and ammonia. This reaction helps to maintain healthy cellular energetics by removing excess AMP that accumulates in energy depleted cells. Furthermore, AMPD permits the synthesis of guanine nucleotides from the larger adenylate pool. This enzyme competes with cytosolic 5'-nucleotidases (c5NT) for AMP. Adenosine, a product of c5NT is a vasodilator, antagonizes inotropic effects of catecholamines and exerts anti-platelet, anti-inflammatory and immunosuppressive activities. The ratio of AMPD/c5NT defines the amount of adenosine produced in adenine nucleotide catabolic pathway. Inhibition of AMPD could alter this ratio resulting in increased adenosine production. Besides the potential effect on adenosine production, elevation of AMP due to inhibition of AMPD could also lead to activation of AMP regulated protein kinase (AMPK) with myriad of downstream events including enhanced energetic metabolism, mitochondrial biogenesis and cytoprotection. While the benefits of these processes are well appreciated in cells such as skeletal or cardiac myocytes its role in protection of endothelium could be even more important. Therapeutic use of AMPD inhibition has been limited due to difficulties with obtaining compounds with adequate characteristics. However, endothelium seems to be the easiest target as effective inhibition of AMPD could be achieved at much lower concentration than in the other types of cells. New generation of AMPD inhibitors has recently been established and its testing in context of endothelial and organ protection could provide important basic knowledge and potential therapeutic tools. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Carbon Dioxide Observational Platform System (CO-OPS), feasibility study

NASA Technical Reports Server (NTRS)

Bouquet, D. L.; Hall, D. W.; Mcelveen, R. P.

1987-01-01

The Carbon Dioxide Observational Platform System (CO-OPS) is a near-space, geostationary, multi-user, unmanned microwave powered monitoring platform system. This systems engineering feasibility study addressed identified existing requirements such as: carbon dioxide observational data requirements, communications requirements, and eye-in-the-sky requirements of other groups like the Defense Department, the Forestry Service, and the Coast Guard. In addition, potential applications in: earth system science, space system sciences, and test and verification (satellite sensors and data management techniques) were considered. The eleven month effort is summarized. Past work and methods of gathering the required observational data were assessed and rough-order-of magnitude cost estimates have shown the CO-OPS system to be most cost effective (less than $30 million within a 10 year lifetime). It was also concluded that there are no technical, schedule, or obstacles that would prevent achieving the objectives of the total 5-year CO-OPS program.

Cellular cAMP uptake as trigger for electrotaxis

NASA Astrophysics Data System (ADS)

Guido, Isabella; Bodenschatz, Eberhard

Cells have the ability to detect continuous current electric fields and respond to them with a directed migratory movement. Dictyostelium discoideum cells, a key model organism for the study of eukaryotic chemotaxis, orient and migrate toward the cathode under the influence of an electric field. The underlying sensing mechanism and whether it is shared by the chemotactic response pathway remains unknown. By investigating the migration in the electric field of cell strains unable to migrate chemotactically (Amib-null) and with defective cAMP relay (ACA-null) we show that the starvation-induced transcription of a set of genes involved in the early developmental stage is not necessary for electrotaxis. However, the analysis of electrotaxis of vegetative cells as well as shortly starved cells shows that cells need to be stimulated with cAMP in order for them to migrate electrotactically. Indeed 30 minutes stimulation with cAMP pulses is enough to let cells orienting with the electric field although during this time the expression of receptors and the beginning of the development has not happened yet. We believe that the reason for this observed phenomenon lies on the endocytosis of the external cAMP which triggers electrotaxis as long as endocytosis and exocytosis are not balanced. This work is part of the MaxSynBio Consortium which is jointly funded by the Federal Ministry of Education and Research of Germany and the Max Planck Society.

Crystal structures of the adenylate sensor from fission yeast AMP-activated protein kinase.

PubMed

Townley, Robert; Shapiro, Lawrence

2007-03-23

The 5'-AMP (adenosine monophosphate)-activated protein kinase (AMPK) coordinates metabolic function with energy availability by responding to changes in intracellular ATP (adenosine triphosphate) and AMP concentrations. Here, we report crystal structures at 2.9 and 2.6 A resolution for ATP- and AMP-bound forms of a core alphabetagamma adenylate-binding domain from the fission yeast AMPK homolog. ATP and AMP bind competitively to a single site in the gamma subunit, with their respective phosphate groups positioned near function-impairing mutants. Unexpectedly, ATP binds without counterions, amplifying its electrostatic effects on a critical regulatory region where all three subunits converge.

The relationship between pulsatile GnRH secretion and cAMP production in immortalized GnRH neurons.

PubMed

Frattarelli, John L; Krsmanovic, Lazar Z; Catt, Kevin J

2011-06-01

In perifused immortalized GnRH neurons (GT1-7), simultaneous measurements of GnRH and cAMP revealed that the secretory profiles for both GnRH and cAMP are pulsatile. An analysis of GnRH and cAMP pulses in 16 independent experiments revealed that 25% of pulses coincide. Inversion of the peak and nadir levels was found in 33% and random relationship between GnRH and cAMP found in 42% of analyzed pulses. The random relation between GnRH and cAMP pulse resets to synchronous after an inverse relation between pulses occurred during the major GnRH release, indicating that GnRH acts as a switching mechanism to synchronize cAMP and GnRH release in perifused GT1-7 neurons. Activation of GnRH receptors with increasing agonist concentrations caused a biphasic change in cAMP levels. Low nanomolar concentrations increased cAMP production, but at high concentrations the initial increase was followed by a rapid decline to below the basal level. Blockade of the GnRH receptors by peptide and nonpeptide antagonists generated monotonic nonpulsatile increases in both GnRH and cAMP production. These findings indicate that cAMP positively regulates GnRH secretion but does not participate in the mechanism of pulsatile GnRH release.

Interband cascade (IC) photovoltaic (PV) architecture for PV devices

DOEpatents

Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

2015-10-20

A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

EXTRACTION AND DETECTION OF A NEW ARSINE SULFIDE CONTAINING ARSENOSUGAR IN MOLLUSCS BY IC-ICP-MS AND IC-ESI-MS/MS

EPA Science Inventory

Using IC-ICP-MS and IC-ESI-MS/MS, an unknown arsenical compound in mollusks has been identified as a new arsine sulfide containing analog of a known arsenosugar and is referred to as As(498). This species has been observed in four separate shellfish species following a mild metha...

Selective Phosphonylation of 5'-Adenosine Monophosphate (5'-AMP) via Pyrophosphite [PPi(III)].

PubMed

Kaye, Karl; Bryant, David E; Marriott, Katie E R; Ohara, Shohei; Fishwick, Colin W G; Kee, Terence P

2016-11-01

We describe here experiments which demonstrate the selective phospho-transfer from a plausibly prebiotic condensed phosphorus (P) salt, pyrophosphite [H 2 P 2 O 5 2- ; PPi(III)], to the phosphate group of 5'-adenosine mono phosphate (5'-AMP). We show further that this P-transfer process is accelerated both by divalent metal ions (M 2+ ) and by organic co-factors such as acetate (AcO - ). In this specific case of P-transfer from PPi(III) to 5'-AMP, we show a synergistic enhancement of transfer in the combined presence of M 2+ & AcO - . Isotopic labelling studies demonstrate that hydrolysis of the phosphonylated 5'-AMP, [P(III)P(V)-5'-AMP], proceeds via nuceophilic attack of water at the Pi(III) terminus.

AMP: a science-driven web-based application for the TeraGrid

NASA Astrophysics Data System (ADS)

Woitaszek, M.; Metcalfe, T.; Shorrock, I.

The Asteroseismic Modeling Portal (AMP) provides a web-based interface for astronomers to run and view simulations that derive the properties of Sun-like stars from observations of their pulsation frequencies. In this paper, we describe the architecture and implementation of AMP, highlighting the lightweight design principles and tools used to produce a functional fully-custom web-based science application in less than a year. Targeted as a TeraGrid science gateway, AMP's architecture and implementation are intended to simplify its orchestration of TeraGrid computational resources. AMP's web-based interface was developed as a traditional standalone database-backed web application using the Python-based Django web development framework, allowing us to leverage the Django framework's capabilities while cleanly separating the user interface development from the grid interface development. We have found this combination of tools flexible and effective for rapid gateway development and deployment.

[Prognostic significance of the cyclic AMP concentration in acute leukemias].

PubMed

Paietta, E; Mittermayer, K; Schwarzmeier, J D

1979-01-01

In patients with acute leukemia (myeloblastic, lymphoblastic, undifferentiated) proliferation kinetics and cyclic adenosine-3', 5'-monophosphate (cAMP) concentration of the leukemic cells were studied for their significance in the prediction of responsiveness to cytostatic therapy. Patients with good clinical response had significantly faster turnover and lower cAMP-levels than those who failed to respond to treatment.

Effect of dibutyryl cyclic AMP on the kinetics of myo-inositol transport in cultured astrocytes.

PubMed

Isaacks, R E; Bender, A S; Reuben, J S; Kim, C Y; Shi, Y F; Norenberg, M D

1999-07-01

Dibutyryl cyclic AMP (dBcAMP) is known to induce maturation and differentiation in astrocytes. As myo-inositol is an important osmoregulator in astrocytes, we examined the effects of maturation and biochemical differentiation on the kinetic properties of myo-inositol transport. Treatment of astrocytes with dBcAMP significantly decreased the Vmax of myo-inositol uptake, but the effect on Km was not significant. The myo-inositol content of astrocytes was significantly decreased in cells treated for 5 days with dBcAMP as compared with untreated controls. Maximum suppression of myo-inositol uptake occurred 7 days after exposure of astrocytes to dBcAMP; this was gradually reversible when dBcAMP was removed from the medium. After exposure to hypertonic medium for 6 h, mRNA expression of the myo-inositol co-transporter was diminished by approximately 36% in astrocytes treated with dBcAMP as compared with untreated cells. It appears that myo-inositol transporters in astrocytes treated with dBcAMP are either decreased in number or inactivated during maturation and differentiation, suggesting that the stage of differentiation and biochemical maturation of astrocytes is an important factor in osmoregulation.

Validation of the OpCost logging cost model using contractor surveys

Treesearch

Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

2017-01-01

OpCost is a harvest and fuel treatment operations cost model developed to function as both a standalone tool and an integrated component of the Bioregional Inventory Originated Simulation Under Management (BioSum) analytical framework for landscape-level analysis of forest management alternatives. OpCost is an updated implementation of the Fuel Reduction Cost Simulator...

30 CFR 57.22102 - Smoking (I-C mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Smoking (I-C mines). 57.22102 Section 57.22102... Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22102 Smoking (I-C mines). (a) Persons shall not smoke or carry smoking materials, matches, or lighters underground or within 50 feet of...

30 CFR 57.22102 - Smoking (I-C mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Smoking (I-C mines). 57.22102 Section 57.22102... Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22102 Smoking (I-C mines). (a) Persons shall not smoke or carry smoking materials, matches, or lighters underground or within 50 feet of...

30 CFR 57.22102 - Smoking (I-C mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Smoking (I-C mines). 57.22102 Section 57.22102... Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22102 Smoking (I-C mines). (a) Persons shall not smoke or carry smoking materials, matches, or lighters underground or within 50 feet of...

30 CFR 57.22102 - Smoking (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Smoking (I-C mines). 57.22102 Section 57.22102... Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22102 Smoking (I-C mines). (a) Persons shall not smoke or carry smoking materials, matches, or lighters underground or within 50 feet of...

Dose and Chemical Modification Considerations for Continuous Cyclic AMP Analog Delivery to the Injured CNS

PubMed Central

Fouad, Karim; Ghosh, Mousumi; Vavrek, Romana; Tse, Arthur D.

2009-01-01

Abstract In this investigation, two cell-permeable synthetic analogs of cAMP, dibutyryl-cAMP (db-cAMP) and 8-bromo-cAMP, which are widely used to elevate intracellular cAMP levels under experimental conditions, were investigated for their ability to dose-dependently improve histological and functional outcomes following continuous delivery in two models of incomplete spinal cord injury (SCI). The cAMP analogs were delivered via osmotic minipumps at 1–250 mM through an indwelling cortical cannula or by intrathecal infusion for up to 4 weeks after either a T8 unilateral over-hemisection or a C2-3 dorsolateral quadrant lesion, respectively. In both SCI models, continuous db-cAMP delivery was associated with histopathological changes that included sporadic micro-hemorrhage formation and cavitation, enhanced macrophage infiltration and tissue damage at regions beyond the immediate application site; no deleterious or beneficial effect of agent delivery was observed at the spinal injury site. Furthermore, these changes were accompanied by pronounced behavioral deficits that included an absence of progressive locomotor recovery, increased extensor tone, paralysis, and sensory abnormalities. These deleterious effects were not observed in saline-treated animals, in animals in which the db-cAMP dose did not exceed 1 mM, or in those animals that received a high dose (250 mM) of the alternative cAMP analog, 8-bromo-cAMP. These results demonstrate that, for continuous intraparenchymal or intrathecal administration of cAMP analogs for the study of biological or therapeutic effects within the central nervous system (CNS), consideration of the effective concentration applied as well as the potential toxicity of chemical moieties on the parent molecule and/or their activity needs to be taken into account. PMID:19397425

Epidemiology and risk factors for infections due to AmpC β-lactamase-producing Escherichia coli.

PubMed

Pascual, Vanesa; Ortiz, Gabriel; Simó, Maria; Alonso, Noemí; Garcia, Maria Consol; Xercavins, Mariona; Rivera, Alba; Morera, Maria Antonia; Miró, Elisenda; Espejo, Elena; Navarro, Ferran; Gurguí, Mercè; Pérez, Josefa; Rodríguez-Carballeira, Mónica; Garau, Javier; Calbo, Esther

2015-03-01

To describe the prevalence and risk factors for infection due to AmpC β-lactamase-producing Escherichia coli (AmpC-EC). For the prevalence study, all clinical isolates of E. coli with reduced susceptibility to third-generation cephalosporins were prospectively included from June 2010 to November 2011. For risk factor analysis, a case-control study was conducted. Cases were patients with an infection due to AmpC-EC. Controls were patients infected with cephalosporin-susceptible E. coli, matched 1 : 2. Detection of blaAmpC genes was done with a multiplex AmpC-PCR, and hyperproduction of E. coli chromosomal blaAmpC by quantitative RT-PCR. Alteration of the blaAmpC promoter was studied by PCR and sequencing. We identified 243 (1.1%) AmpC-EC strains out of 21 563 clinical isolates. Three cases with strains carrying ESBLs, 18 strains that were considered due to colonization and 8 cases lost to clinical follow-up were excluded. Finally, 214 cases were included in the analysis. Ninety-one cases (42.5%) and 269 (62.8%) controls were strictly community acquired (P < 0.001). Thirty-five (16.3%) cases and 186 controls (43.5%) did not have any identifiable risk factor (P < 0.001). Among cases, 158 (73.8%) were found to harbour an acquired AmpC (73.4% CMY-2). Previous use of fluoroquinolones [OR 2.6 (95% CI 1.12-3.36); P = 0.008] was independently associated with AmpC-EC in the multivariate analysis. Prevalence of AmpC in E. coli remains low in our area. Plasmid acquisition (CMY type) represents the main mechanism of AmpC production. A high proportion of community-acquired isolates and patients with no identifiable risk factors were found. Previous use of fluoroquinolones was identified as a risk factor. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Analysis of Advanced Modular Power Systems (AMPS) for Deep Space Exploration

NASA Technical Reports Server (NTRS)

Oeftering, Richard; Soeder, James F.; Beach, Ray

2014-01-01

The Advanced Modular Power Systems (AMPS) project is developing a modular approach to spacecraft power systems for exploration beyond Earth orbit. AMPS is intended to meet the need of reducing the cost of design development, test and integration and also reducing the operational logistics cost of supporting exploration missions. AMPS seeks to establish modular power building blocks with standardized electrical, mechanical, thermal and data interfaces that can be applied across multiple exploration vehicles. The presentation discusses the results of a cost analysis that compares the cost of the modular approach against a traditional non-modular approach.

cAMP signaling in skeletal muscle adaptation: hypertrophy, metabolism, and regeneration

PubMed Central

Stewart, Randi

2012-01-01

Among organ systems, skeletal muscle is perhaps the most structurally specialized. The remarkable subcellular architecture of this tissue allows it to empower movement with instructions from motor neurons. Despite this high degree of specialization, skeletal muscle also has intrinsic signaling mechanisms that allow adaptation to long-term changes in demand and regeneration after acute damage. The second messenger adenosine 3′,5′-monophosphate (cAMP) not only elicits acute changes within myofibers during exercise but also contributes to myofiber size and metabolic phenotype in the long term. Strikingly, sustained activation of cAMP signaling leads to pronounced hypertrophic responses in skeletal myofibers through largely elusive molecular mechanisms. These pathways can promote hypertrophy and combat atrophy in animal models of disorders including muscular dystrophy, age-related atrophy, denervation injury, disuse atrophy, cancer cachexia, and sepsis. cAMP also participates in muscle development and regeneration mediated by muscle precursor cells; thus, downstream signaling pathways may potentially be harnessed to promote muscle regeneration in patients with acute damage or muscular dystrophy. In this review, we summarize studies implicating cAMP signaling in skeletal muscle adaptation. We also highlight ligands that induce cAMP signaling and downstream effectors that are promising pharmacological targets. PMID:22354781

An investigation of potential applications of OP-SAPS: Operational sampled analog processors

NASA Technical Reports Server (NTRS)

Parrish, E. A.; Mcvey, E. S.

1976-01-01

The impact of charge-coupled device (CCD) processors on future instrumentation was investigated. The CCD devices studied process sampled analog data and are referred to as OP-SAPS - operational sampled analog processors. Preliminary studies into various architectural configurations for systems composed of OP-SAPS show that they have potential in such diverse applications as pattern recognition and automatic control. It appears probable that OP-SAPS may be used to construct computing structures which can serve as special peripherals to large-scale computer complexes used in real time flight simulation. The research was limited to the following benchmark programs: (1) face recognition, (2) voice command and control, (3) terrain classification, and (4) terrain identification. A small amount of effort was spent on examining a method by which OP-SAPS may be used to decrease the limiting ground sampling distance encountered in remote sensing from satellites.

OP-AMPS on Flexible Substrates with Printable Materials

DTIC Science & Technology

2011-08-10

Zinc Tin Oxide Thin - Film - Transistor Enhancement...II196, 2010. [3] D. Geng, D. H. Kang, and J. Jang, "High-Performance Amorphous Indium-Gallium- Zinc - Oxide Thin - Film Transistor With a Self-Aligned...B., Dodabalapur, A., “Band transport and mobility edge in amorphous solution-processed zinc tin oxide thin - film transistors ”, Applied

A radial velocity survey of the open cluster IC 4665

NASA Technical Reports Server (NTRS)

Prosser, Charles F.; Giampapa, Mark S.

1994-01-01

A radial velocity survey of the open cluster IC 4665 is reported for a group of candidate members previously identified on the basis of proper motion and photometry. Of those candidates observed, 20 out of 42 have radial velocities consistent with membership; these cluster members populate the F5-K0 dwarf region and represent the first relatively conclusive membership determinations for such solar-type stars in IC 4665. Three new spectroscopic binary members of the cluster have been identified. Rotational velocities have also been derived; the v sin i distribution among IC 4665 members reveals that most apparent G dwarf members of IC 4665 are seen to exhibit substantial rotation (v sin i greater than 10 km/s). When compared to evolutionary isochrones, the current list of intermediate-mass members appears to support earlier suggestions that IC 4665 has an age comparable to the Pleiades.

The localization and concentration of the PDE2-encoded high-affinity cAMP phosphodiesterase is regulated by cAMP-dependent protein kinase A in the yeast Saccharomyces cerevisiae.

PubMed

Hu, Yun; Liu, Enkai; Bai, Xiaojia; Zhang, Aili

2010-03-01

The genome of the yeast Saccharomyces cerevisiae encodes two cyclic AMP (cAMP) phosphodiesterases, a low-affinity one, Pde1, and a high-affinity one, Pde2. Pde1 has been ascribed a function for downregulating agonist-induced cAMP accumulation in a protein kinase A (PKA)-governed negative feedback loop, whereas Pde2 controls the basal cAMP level in the cell. Here we show that PKA regulates the localization and protein concentration of Pde2. Pde2 is accumulated in the nucleus in wild-type cells growing on glucose, or in strains with hyperactive PKA. In contrast, in derepressed wild-type cells or cells with attenuated PKA activity, Pde2 is distributed over the nucleus and cytoplasm. We also show evidence indicating that the Pde2 protein level is positively correlated with PKA activity. The increase in the Pde2 protein level in high-PKA strains and in cells growing on glucose was due to its increased half-life. These results suggest that, like its low-affinity counterpart, the high-affinity phosphodiesterase may also play an important role in the PKA-controlled feedback inhibition of intracellular cAMP.

cAMP controls rod photoreceptor sensitivity via multiple targets in the phototransduction cascade

PubMed Central

Astakhova, Luba A.; Samoiliuk, Evgeniia V.; Govardovskii, Victor I.

2012-01-01

In early studies, both cyclic AMP (cAMP) and cGMP were considered as potential secondary messengers regulating the conductivity of the vertebrate photoreceptor plasma membrane. Later discovery of the cGMP specificity of cyclic nucleotide–gated channels has shifted attention to cGMP as the only secondary messenger in the phototransduction cascade, and cAMP is not considered in modern schemes of phototransduction. Here, we report evidence that cAMP may also be involved in regulation of the phototransduction cascade. Using a suction pipette technique, we recorded light responses of isolated solitary rods from the frog retina in normal solution and in the medium containing 2 µM of adenylate cyclase activator forskolin. Under forskolin action, flash sensitivity rose more than twofold because of a retarded photoresponse turn-off. The same concentration of forskolin lead to a 2.5-fold increase in the rod outer segment cAMP, which is close to earlier reported natural day/night cAMP variations. Detailed analysis of cAMP action on the phototransduction cascade suggests that several targets are affected by cAMP increase: (a) basal dark phosphodiesterase (PDE) activity decreases; (b) at the same intensity of light background, steady background-induced PDE activity increases; (c) at light backgrounds, guanylate cyclase activity at a given fraction of open channels is reduced; and (d) the magnitude of the Ca2+ exchanger current rises 1.6-fold, which would correspond to a 1.6-fold elevation of [Ca2+]in. Analysis by a complete model of rod phototransduction suggests that an increase of [Ca2+]in might also explain effects (b) and (c). The mechanism(s) by which cAMP could regulate [Ca2+]in and PDE basal activity is unclear. We suggest that these regulations may have adaptive significance and improve the performance of the visual system when it switches between day and night light conditions. PMID:23008435

Increase in Ca2+ current by sustained cAMP levels enhances proliferation rate in GH3 cells.

PubMed

Rodrigues, Andréia Laura; Brescia, Marcella; Koschinski, Andreas; Moreira, Thaís Helena; Cameron, Ryan T; Baillie, George; Beirão, Paulo S L; Zaccolo, Manuela; Cruz, Jader S

2018-01-01

Ca 2+ and cAMP are important intracellular modulators. In order to generate intracellular signals with various amplitudes, as well as different temporal and spatial properties, a tightly and precise control of these modulators in intracellular compartments is necessary. The aim of this study was to evaluate the effects of elevated and sustained cAMP levels on voltage-dependent Ca 2+ currents and proliferation in pituitary tumor GH3 cells. Effect of long-term exposure to forskolin and dibutyryl-cyclic AMP (dbcAMP) on Ca 2+ current density and cell proliferation rate were determined by using the whole-cell patch-clamp technique and real time cell monitoring system. The cAMP levels were assayed, after exposing transfected GH3 cells with the EPAC-1 cAMP sensor to forskolin and dbcAMP, by FRET analysis. Sustained forskolin treatment (24 and 48h) induced a significant increase in total Ca 2+ current density in GH3 cells. Accordingly, dibutyryl-cAMP incubation (dbcAMP) also elicited increase in Ca 2+ current density. However, the maximum effect of dbcAMP occurred only after 72h incubation, whereas forskolin showed maximal effect at 48h. FRET-experiments confirmed that the time-course to elevate intracellular cAMP was distinct between forskolin and dbcAMP. Mibefradil inhibited the fast inactivating current component selectively, indicating the recruitment of T-type Ca 2+ channels. A significant increase on cell proliferation rate, which could be related to the elevated and sustained intracellular levels of cAMP was observed. We conclude that maintaining high levels of intracellular cAMP will cause an increase in Ca 2+ current density and this phenomenon impacts proliferation rate in GH3 cells. Copyright © 2017 Elsevier Inc. All rights reserved.

The Applied Mathematics for Power Systems (AMPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chertkov, Michael

2012-07-24

Increased deployment of new technologies, e.g., renewable generation and electric vehicles, is rapidly transforming electrical power networks by crossing previously distinct spatiotemporal scales and invalidating many traditional approaches for designing, analyzing, and operating power grids. This trend is expected to accelerate over the coming years, bringing the disruptive challenge of complexity, but also opportunities to deliver unprecedented efficiency and reliability. Our Applied Mathematics for Power Systems (AMPS) Center will discover, enable, and solve emerging mathematics challenges arising in power systems and, more generally, in complex engineered networks. We will develop foundational applied mathematics resulting in rigorous algorithms and simulation toolboxesmore » for modern and future engineered networks. The AMPS Center deconstruction/reconstruction approach 'deconstructs' complex networks into sub-problems within non-separable spatiotemporal scales, a missing step in 20th century modeling of engineered networks. These sub-problems are addressed within the appropriate AMPS foundational pillar - complex systems, control theory, and optimization theory - and merged or 'reconstructed' at their boundaries into more general mathematical descriptions of complex engineered networks where important new questions are formulated and attacked. These two steps, iterated multiple times, will bridge the growing chasm between the legacy power grid and its future as a complex engineered network.« less

Microgravity changes in heart structure and cyclic-AMP metabolism

NASA Technical Reports Server (NTRS)

Philpott, D. E.; Fine, A.; Kato, K.; Egnor, R.; Cheng, L.

1985-01-01

The effects of microgravity on cardiac ultrastructure and cyclic AMP metabolism in tissues of rats flown on Spacelab 3 are reported. Light and electron microscope studies of cell structure, measurements of low and high Km phosphodiesterase activity, cyclic AMP-dependent protein kinase activity, and regulatory subunit compartmentation show significant deviations in flight animals when compared to ground controls. The results indicate that some changes have occurred in cellular responses associated with catecholamine receptor interactions and intracellular signal processing.

OpCost: an open-source system for estimating costs of stand-level forest operations

Treesearch

Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

2017-01-01

This report describes and documents the OpCost forest operations cost model, a key component of the BioSum analysis framework. OpCost is available in two editions: as a callable module for use with BioSum, and in a stand-alone edition that can be run directly from R. OpCost model logic and assumptions for this open-source tool are explained, references to the...

cAMP modulates multiple K+ currents, increasing spike duration and excitability in Aplysia sensory neurons.

PubMed

Goldsmith, B A; Abrams, T W

1992-12-01

Enhancement of the defensive withdrawal reflex of Aplysia involves a prolongation of the action potentials of mechanosensory neurons, which contributes to facilitation of transmitter release from these cells. Recent reports have suggested that whereas cAMP-dependent modulation of K+ current increases sensory neuron excitability, a cAMP-independent decrease in K+ current may increase the action potential duration and, thus, facilitate transmitter release. We have tested this proposal using Walsh cAMP-dependent protein kinase inhibitor or activators of the cAMP cascade and found that cAMP plays a major role in the spike-broadening effects of facilitatory transmitter; however, broadening requires higher levels of activation of the cAMP-dependent kinase than does increasing excitability. A steeply voltage-dependent transient K+ current, termed IKV,early, and the slowly activating S-type K+ (S-K+) current are both reduced by activation of the cAMP cascade, although with different sensitivities to the second messenger, enabling excitability and spike duration to be regulated independently. Differences in cAMP sensitivity also suggested that the originally described S-K+ current actually consists of two independent components, a slowly activating component and a time-independent, "steady-state" current that is activated at rest.

The cAMP Pathway as Therapeutic Target in Autoimmune and Inflammatory Diseases

PubMed Central

Raker, Verena Katharina; Becker, Christian; Steinbrink, Kerstin

2016-01-01

Nucleotide signaling molecules contribute to the regulation of cellular pathways. In the immune system, cyclic adenosine monophosphate (cAMP) is well established as a potent regulator of innate and adaptive immune cell functions. Therapeutic strategies to interrupt or enhance cAMP generation or effects have immunoregulatory potential in autoimmune and inflammatory disorders. Here, we provide an overview of the cyclic AMP axis and its role as a regulator of immune functions and discuss the clinical and translational relevance of interventions with these processes. PMID:27065076

PDF and cAMP enhance PER stability in Drosophila clock neurons

PubMed Central

Li, Yue; Guo, Fang; Shen, James; Rosbash, Michael

2014-01-01

The neuropeptide PDF is important for Drosophila circadian rhythms: pdf01 (pdf-null) animals are mostly arrhythmic or short period in constant darkness and have an advanced activity peak in light–dark conditions. PDF contributes to the amplitude, synchrony, as well as the pace of circadian rhythms within clock neurons. PDF is known to increase cAMP levels in PDR receptor (PDFR)-containing neurons. However, there is no known connection of PDF or of cAMP with the Drosophila molecular clockworks. We discovered that the mutant period gene perS ameliorates the phenotypes of pdf-null flies. The period protein (PER) is a well-studied repressor of clock gene transcription, and the perS protein (PERS) has a markedly short half-life. The result therefore suggests that the PDF-mediated increase in cAMP might lengthen circadian period by directly enhancing PER stability. Indeed, increasing cAMP levels and cAMP-mediated protein kinase A (PKA) activity stabilizes PER, in S2 tissue culture cells and in fly circadian neurons. Adding PDF to fly brains in vitro has a similar effect. Consistent with these relationships, a light pulse causes more prominent PER degradation in pdf01 circadian neurons than in wild-type neurons. The results indicate that PDF contributes to clock neuron synchrony by increasing cAMP and PKA, which enhance PER stability and decrease clock speed in intrinsically fast-paced PDFR-containing clock neurons. We further suggest that the more rapid degradation of PERS bypasses PKA regulation and makes the pace of clock neurons more uniform, allowing them to avoid much of the asynchrony caused by the absence of PDF. PMID:24707054

PDF and cAMP enhance PER stability in Drosophila clock neurons.

PubMed

Li, Yue; Guo, Fang; Shen, James; Rosbash, Michael

2014-04-01

The neuropeptide PDF is important for Drosophila circadian rhythms: pdf(01) (pdf-null) animals are mostly arrhythmic or short period in constant darkness and have an advanced activity peak in light-dark conditions. PDF contributes to the amplitude, synchrony, as well as the pace of circadian rhythms within clock neurons. PDF is known to increase cAMP levels in PDR receptor (PDFR)-containing neurons. However, there is no known connection of PDF or of cAMP with the Drosophila molecular clockworks. We discovered that the mutant period gene per(S) ameliorates the phenotypes of pdf-null flies. The period protein (PER) is a well-studied repressor of clock gene transcription, and the per(S) protein (PERS) has a markedly short half-life. The result therefore suggests that the PDF-mediated increase in cAMP might lengthen circadian period by directly enhancing PER stability. Indeed, increasing cAMP levels and cAMP-mediated protein kinase A (PKA) activity stabilizes PER, in S2 tissue culture cells and in fly circadian neurons. Adding PDF to fly brains in vitro has a similar effect. Consistent with these relationships, a light pulse causes more prominent PER degradation in pdf(01) circadian neurons than in wild-type neurons. The results indicate that PDF contributes to clock neuron synchrony by increasing cAMP and PKA, which enhance PER stability and decrease clock speed in intrinsically fast-paced PDFR-containing clock neurons. We further suggest that the more rapid degradation of PERS bypasses PKA regulation and makes the pace of clock neurons more uniform, allowing them to avoid much of the asynchrony caused by the absence of PDF.

Cyclic AMP-receptor protein activates aerobactin receptor IutA expression in Vibrio vulnificus.

PubMed

Kim, Choon-Mee; Kim, Seong-Jung; Shin, Sung-Heui

2012-04-01

The ferrophilic bacterium Vibrio vulnificus can utilize the siderophore aerobactin of Escherichia coli for iron acquisition via its specific receptor IutA. This siderophore piracy by V. vulnificus may contribute to its survival and proliferation, especially in mixed bacterial environments. In this study, we examined the effects of glucose, cyclic AMP (cAMP), and cAMP-receptor protein (Crp) on iutA expression in V. vulnificus. Glucose dose-dependently repressed iutA expression. A mutation in cya encoding adenylate cyclase required for cAMP synthesis severely repressed iutA expression, and this change was recovered by in trans complementing cya or the addition of exogenous cAMP. Furthermore, a mutation in crp encoding Crp severely repressed iutA expression, and this change was recovered by complementing crp. Accordingly, glucose deprivation under iron-limited conditions is an environmental signal for iutA expression, and Crp functions as an activator that regulates iutA expression in response to glucose availability.

5′-AMP impacts lymphocyte recirculation through activation of A2B receptors

PubMed Central

Bouma, Hjalmar R.; Mandl, Judith N.; Strijkstra, Arjen M.; Boerema, Ate S.; Kok, Jan-Willem; van Dam, Annie; IJzerman, Ad; Kroese, Frans G. M.; Henning, Robert H.

2013-01-01

Natural hibernation consists of torpid phases with metabolic suppression alternating with euthermic periods. Induction of torpor holds substantial promise in various medical conditions, including trauma, major surgery, and transplantation. Torpor in mice can be induced pharmacologically by 5′-AMP. Previously, we showed that during natural torpor, the reduction in body temperature results in lymphopenia via a reduction in plasma S1P. Here, we show that during torpor induced by 5′-AMP, there is a similar reduction in the number of circulating lymphocytes that is a result of their retention in secondary lymphoid organs. This lymphopenia could be mimicked by engagement of A2BRs by a selective A2BR agonist (LUF6210) in the absence of changes in temperature and prevented by A2BR antagonists during 5′-AMP-induced torpor. In addition, forced cooling of mice led to peripheral blood lymphopenia, independent of A2BR signaling. The induction of torpor using 5′-AMP impacted the migration of lymphocytes within and between secondary lymphoid organs. During torpor, the homing into LNs was impaired, and two-photon intravital microscopy revealed that cell motility was decreased significantly and rapidly upon 5′-AMP administration. Furthermore, the S1P plasma concentration was reduced by 5′-AMP but not by LUF6210. S1P plasma levels restored upon arousal. Likely, the reduced migration in LNs combined with the reduced S1P plasma level substantially reduces lymphocyte egress after injection of 5′-AMP. In conclusion, 5′-AMP induces a state of pharmacological torpor in mice, during which, lymphopenia is governed primarily by body temperature-independent suppression of lymphocyte egress from LNs. PMID:23682128

Biatriosporin D displays anti-virulence activity through decreasing the intracellular cAMP levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Ming; Chang, Wenqiang; Shi, Hongzhuo

Candidiasis has long been a serious human health problem, and novel antifungal approaches are greatly needed. During both superficial and systemic infection, C. albicans relies on a battery of virulence factors, such as adherence, filamentation, and biofilm formation. In this study, we found that a small phenolic compound, Biatriosporin D (BD), isolated from an endolichenic fungus, Biatriospora sp., displayed anti-virulence activity by inhibiting adhesion, hyphal morphogenesis and biofilm formation of C. albicans. Of note is the high efficacy of BD in preventing filamentation with a much lower dose than its MIC value. Furthermore, BD prolonged the survival of worms infectedmore » by C. albicans in vivo. Quantitative real-time PCR analysis, exogenous cAMP rescue experiments and intracellular cAMP measurements revealed that BD regulates the Ras1-cAMP-Efg1 pathway by reducing cAMP levels to inhibit the hyphal formation. Further investigation showed that BD could upregulate Dpp3 to synthesize much more farnesol, which could inhibit the activity of Cdc35 and reduce the generation of cAMP. Taken together, these findings indicate that BD stimulates the expression of Dpp3 to synthesize more farnesol that directly inhibits the Cdc35 activity, reducing intracellular cAMP and thereby disrupting the morphologic transition and attenuating the virulence of C. albicans. Our study uncovers the underlying mechanism of BD as a prodrug in fighting against pathogenic C. albicans and provides a potential application of BD in fighting clinically relevant fungal infections by targeting fungal virulence. - Highlights: • BD inhibits the filamentation of C. albicans in multiple hypha-inducing conditions. • BD can prolong the survival of nematodes infected by C. albicans. • BD stimulates the expression of Dpp3 to synthesize more farnesol. • BD reduces intracellular cAMP and regulates Ras1-cAMP-PKA pathway.« less

The MetOp second generation 3MI instrument

NASA Astrophysics Data System (ADS)

Manolis, Ilias; Grabarnik, Semen; Caron, Jérôme; Bézy, Jean-Loup; Loiselet, Marc; Betto, Maurizio; Barré, Hubert; Mason, Graeme; Meynart, Roland

2013-10-01

The MetOp-SG programme is a joint Programme of EUMETSAT and ESA. ESA develops the prototype MetOp-SG satellites (including associated instruments) and procures, on behalf of EUMETSAT, the recurrent satellites (and associated instruments). Two parallel, competitive phase A/B1 studies for MetOp Second Generation (MetOp-SG) have been concluded in May 2013. The implementation phases (B2/C/D/E) are planned to start the first quarter of 2014. ESA is responsible for instrument design of six missions, namely Microwave Sounding Mission (MWS), Scatterometer mission (SCA), Radio Occultation mission (RO), Microwave Imaging mission (MWI), Ice Cloud Imager (ICI) and Multi-viewing, Multi-channel, Multi-polarisation imaging mission (3MI). The paper will present the main performances of the 3MI instrument and will highlight the performance improvements with respect to its heritage derived by the POLDER instrument, such as number of spectral channels and spectral range coverage, swath and ground spatial resolution. The engineering of some key performance requirements (multi-viewing, polarisation sensitivity, straylight etc.) will also be discussed. The results of the feasibility studies will be presented together with the programmatics for the instrument development. Several pre-development activities have been initiated to retire highest risks and to demonstrate the ultimate performances of the 3MI optics. The scope, objectives and current status of those activities will be presented. Key technologies involved in the 3MI instrument design and implementation are considered to be: the optical design featuring aspheric optics, the implementation of broadband Anti Reflection coatings featuring low polarisation and low de-phasing properties, the development and qualification of polarisers with acceptable performances as well as spectral filters with good uniformities over a large clear aperture.

Extracellular cAMP activates molecular signalling pathways associated with sperm capacitation in bovines.

PubMed

Alonso, Carlos Agustín I; Osycka-Salut, Claudia E; Castellano, Luciana; Cesari, Andreína; Di Siervi, Nicolás; Mutto, Adrián; Johannisson, Anders; Morrell, Jane M; Davio, Carlos; Perez-Martinez, Silvina

2017-08-01

Is extracellular cAMP involved in the regulation of signalling pathways in bovine sperm capacitation? Extracellular cAMP induces sperm capacitation through the activation of different signalling pathways that involve phospholipase C (PLC), PKC/ERK1-2 signalling and an increase in sperm Ca2+ levels, as well as soluble AC and cAMP/protein kinase A (PKA) signalling. In order to fertilize the oocyte, ejaculated spermatozoa must undergo a series of changes in the female reproductive tract, known as capacitation. This correlates with a number of membrane and metabolic modifications that include an increased influx of bicarbonate and Ca2+, activation of a soluble adenylyl cyclase (sAC) to produce cAMP, PKA activation, protein tyrosine phosphorylation and the development of hyperactivated motility. We previously reported that cAMP efflux by Multidrug Resistance Protein 4 (MRP4) occurs during sperm capacitation and the pharmacological blockade of this inhibits the process. Moreover, the supplementation of incubation media with cAMP abolishes the inhibition and leads to sperm capacitation, suggesting that extracellular cAMP regulates crucial signalling cascades involved in this process. Bovine sperm were selected by the wool glass column method, and washed by centrifugation in BSA-Free Tyrode's Albumin Lactate Pyruvate (sp-TALP). Pellets were resuspended then diluted for each treatment. For in vitro capacitation, 10 to 15 × 106 SPZ/ml were incubated in 0.3% BSA sp-TALP at 38.5°C for 45 min under different experimental conditions. To evaluate the role of extracellular cAMP on different events associated with sperm capacitation, 10 nM cAMP was added to the incubation medium as well as different inhibitors of enzymes associated with signalling transduction pathways: U73122 (PLC inhibitor, 10 μM), Gö6983 (PKC inhibitor, 10 μM), PD98059 (ERK-1/2 inhibitor, 30 μM), H89 and KT (PKA inhibitors, 50 μM and 100 nM, respectively), KH7 (sAC inhibitor, 10 μM), BAPTA

Ultra-sensitive PSA Following Prostatectomy Reliably Identifies Patients Requiring Post-Op Radiotherapy

PubMed Central

Kang, Jung Julie; Reiter, Robert; Steinberg, Michael; King, Christopher R.

2015-01-01

PURPOSE Integrating ultra-sensitive PSA (uPSA) into surveillance of high-risk patients following radical prostatectomy (RP) potentially optimizes management by correctly identifying actual recurrences, promoting an early salvage strategy and minimizing overtreatment. The power of uPSA following surgery to identify eventual biochemical failures is tested. PATIENTS AND METHODS From 1991–2013, 247 high-risk patients with a median follow-up was 44 months after RP were identified (extraprostatic extension and/or positive margin). Surgical technique, initial PSA (iPSA), pathology and post-op PSA were analyzed. The uPSA assay threshold was 0.01 ng/mL. Conventional biochemical relapse (cBCR) was defined as PSA ≥0.2 ng/mL. Kaplan Meier and Cox multivariate analyses (MVA) compared uPSA recurrence vs. cBCR rates. RESULTS Sensitivity analysis identified uPSA ≥0.03 as the optimal threshold identifying recurrence. First post-op uPSA ≥0.03, Gleason grade, T-stage, iPSA, and margin status predicted cBCR. On MVA, only first post-op uPSA ≥0.03, Gleason grade, and T-stage independently predicted cBCR. First post-op uPSA ≥0.03 conferred the highest risk (HR 8.5, p<0.0001) and discerned cBCR with greater sensitivity than undetectable first conventional PSA (70% vs. 46%). Any post-op PSA ≥0.03 captured all failures missed by first post-op value (100% sensitivity) with accuracy (96% specificity). Defining failure at uPSA ≥0.03 yielded a median lead-time advantage of 18 months (mean 24 months) over the conventional PSA ≥0.2 definition. CONCLUSION uPSA ≥0.03 is an independent factor, identifies BCR more accurately than any traditional risk factors, and confers a significant lead-time advantage. uPSA enables critical decisions regarding timing and indication for post-op RT among high-risk patients following RP. PMID:25463990

N-Acetyl-D- and L-esters of 5'-AMP hydrolyze at different rates

NASA Technical Reports Server (NTRS)

Wickramasinghe, N. S.; Lacey, J. C. Jr; Lacey JC, J. r. (Principal Investigator)

1993-01-01

Studies of the properties of aminoacyl derivatives of 5'-AMP are aimed at understanding the origin of the process of protein synthesis. Aminoacyl (2',3') esters of 5'-AMP can serve as models of the 3'-terminus of aminoacyl tRNA. We report here on the relative rates of hydrolysis of Ac-D- and L-Phe AMP esters as a function of pH. At all pHs above 3, the rate constant of hydrolysis of the Ac-L-Phe ester is 1.7 to 2.1 times that of Ac-D-Phe ester. The D-isomer seems partially protected from hydrolysis by a stronger association with the adenine ring of the 5'-AMP.

DSN G/T(sub op) and telecommunications system performance

NASA Technical Reports Server (NTRS)

Stelzried, C.; Clauss, R.; Rafferty, W.; Petty, S.

1992-01-01

Provided here is an intersystem comparison of present and evolving Deep Space Network (DSN) microwave receiving systems. Comparisons of the receiving systems are based on the widely used G/T sub op figure of merit, which is defined as antenna gain divided by operating system noise temperature. In 10 years, it is expected that the DSN 32 GHz microwave receiving system will improve the G/T sub op performance over the current 8.4 GHz system by 8.3 dB. To compare future telecommunications system end-to-end performance, both the receiving systems' G/T sub op and spacecraft transmit parameters are used. Improving the 32 GHz spacecraft transmitter system is shown to increase the end-to-end telecommunications system performance an additional 3.2 dB, for a net improvement of 11.5 dB. These values are without a planet in the field of view (FOV). A Saturn mission is used for an example calculation to indicate the degradation in performance with a planet in the field of view.

Investigation of cAMP microdomains as a path to novel cancer diagnostics.

PubMed

Desman, Garrett; Waintraub, Caren; Zippin, Jonathan H

2014-12-01

Understanding of cAMP signaling has greatly improved over the past decade. The advent of live cell imaging techniques and more specific pharmacologic modulators has led to an improved understanding of the intricacies by which cAMP is able to modulate such a wide variety of cellular pathways. It is now appreciated that cAMP is able to activate multiple effector proteins at distinct areas in the cell leading to the activation of very different downstream targets. The investigation of signaling proteins in cancer is a common route to the development of diagnostic tools, prognostic tools, and/or therapeutic targets, and in this review we highlight how investigation of cAMP signaling microdomains driven by the soluble adenylyl cyclase in different cancers has led to the development of a novel cancer biomarker. Antibodies directed against the soluble adenylyl cyclase (sAC) are highly specific markers for melanoma especially for lentigo maligna melanoma and are being described as "second generation" cancer diagnostics, which are diagnostics that determine the 'state' of a cell and not just identify the cell type. Due to the wide presence of cAMP signaling pathways in cancer, we predict that further investigation of both sAC and other cAMP microdomains will lead to additional cancer biomarkers. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of Acanthamoeba Myosin-IC as a Potential Therapeutic Target

PubMed Central

Lorenzo-Morales, Jacob; López-Arencibia, Atteneri; Reyes-Batlle, María; Piñero, José E.; Valladares, Basilio; Maciver, Sutherland K.

2014-01-01

Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a fatal encephalitis. We have targeted myosin-IC by using small interfering RNA (siRNA) silencing as a therapeutic approach, since it is known that the function of this protein is vital for the amoeba. In this work, specific siRNAs against the Acanthamoeba myosin-IC gene were developed. Treated and control amoebae were cultured in growth and encystment media to evaluate the induced effects after myosin-IC gene knockdown, as we have anticipated that cyst formation may be impaired. The effects of myosin-IC gene silencing were inhibition of cyst formation, inhibition of completion of cytokinesis, inhibition of osmoregulation under osmotic stress conditions, and death of the amoebae. The finding that myosin-IC silencing caused incompletion of cytokinesis is in agreement with earlier suggestions that the protein plays a role in cell locomotion, which is necessary to pull daughter cells apart after mitosis in a process known as “traction-mediated cytokinesis”. We conclude that myosin-IC is a very promising potential drug target for the development of much-needed antiamoebal drugs and that it should be further exploited for Acanthamoeba therapy. PMID:24468784

AMP and adenosine are both ligands for adenosine 2B receptor signaling.

PubMed

Holien, Jessica K; Seibt, Benjamin; Roberts, Veena; Salvaris, Evelyn; Parker, Michael W; Cowan, Peter J; Dwyer, Karen M

2018-01-15

Adenosine is considered the canonical ligand for the adenosine 2B receptor (A 2B R). A 2B R is upregulated following kidney ischemia augmenting post ischemic blood flow and limiting tubular injury. In this context the beneficial effect of A 2B R signaling has been attributed to an increase in the pericellular concentration of adenosine. However, following renal ischemia both kidney adenosine monophosphate (AMP) and adenosine levels are substantially increased. Using computational modeling and calcium mobilization assays, we investigated whether AMP could also be a ligand for A 2B R. The computational modeling suggested that AMP interacts with more favorable energy to A 2B R compared with adenosine. Furthermore, AMPαS, a non-hydrolyzable form of AMP, increased calcium uptake by Chinese hamster ovary (CHO) cells expressing the human A 2B R, indicating preferential signaling via the G q pathway. Therefore, a putative AMP-A 2B R interaction is supported by the computational modeling data and the biological results suggest this interaction involves preferential G q activation. These data provide further insights into the role of purinergic signaling in the pathophysiology of renal IRI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Essential role of the cAMP-cAMP response-element binding protein pathway in opiate-induced homeostatic adaptations of locus coeruleus neurons.

PubMed

Cao, Jun-Li; Vialou, Vincent F; Lobo, Mary Kay; Robison, Alfred J; Neve, Rachael L; Cooper, Donald C; Nestler, Eric J; Han, Ming-Hu

2010-09-28

Excessive inhibition of brain neurons in primary or slice cultures can induce homeostatic intrinsic plasticity, but the functional role and underlying molecular mechanisms of such plasticity are poorly understood. Here, we developed an ex vivo locus coeruleus (LC) slice culture system and successfully recapitulated the opiate-induced homeostatic adaptation in electrical activity of LC neurons seen in vivo. We investigated the mechanisms underlying this adaptation in LC slice cultures by use of viral-mediated gene transfer and genetic mutant mice. We found that short-term morphine treatment of slice cultures almost completely abolished the firing of LC neurons, whereas chronic morphine treatment increased LC neuronal excitability as revealed during withdrawal. This increased excitability was mediated by direct activation of opioid receptors and up-regulation of the cAMP pathway and accompanied by increased cAMP response-element binding protein (CREB) activity. Overexpression of a dominant negative CREB mutant blocked the increase in LC excitability induced by morphine- or cAMP-pathway activation. Knockdown of CREB in slice cultures from floxed CREB mice similarly decreased LC excitability. Furthermore, the ability of morphine or CREB overexpression to up-regulate LC firing was blocked by knockout of the CREB target adenylyl cyclase 8. Together, these findings provide direct evidence that prolonged exposure to morphine induces homeostatic plasticity intrinsic to LC neurons, involving up-regulation of the cAMP-CREB signaling pathway, which then enhances LC neuronal excitability.

Crystal structures of RIalpha subunit of cyclic adenosine 5'-monophosphate (cAMP)-dependent protein kinase complexed with (Rp)-adenosine 3',5'-cyclic monophosphothioate and (Sp)-adenosine 3',5'-cyclic monophosphothioate, the phosphothioate analogues of cAMP.

PubMed

Wu, Jian; Jones, John M; Nguyen-Huu, Xuong; Ten Eyck, Lynn F; Taylor, Susan S

2004-06-01

Cyclic adenosine 5'-monophosphate (cAMP) is an ancient signaling molecule, and in vertebrates, a primary target for cAMP is cAMP-dependent protein kinase (PKA). (R(p))-adenosine 3',5'-cyclic monophosphothioate ((R(p))-cAMPS) and its analogues are the only known competitive inhibitors and antagonists for cAMP activation of PKA, while (S(p))-adenosine 3',5'-cyclic monophosphothioate ((S(p))-cAMPS) functions as an agonist. The crystal structures of a Delta(1-91) deletion mutant of the RIalpha regulatory subunit of PKA bound to (R(p))-cAMPS and (S(p))-cAMPS were determined at 2.4 and 2.3 A resolution, respectively. While the structures are similar to each other and to the crystal structure of RIalpha bound to cAMP, differences in the dynamical properties of the protein when (R(p))-cAMPS is bound are apparent. The structures highlight the critical importance of the exocyclic oxygen's interaction with the invariant arginine in the phosphate binding cassette (PBC) and the importance of this interaction for the dynamical properties of the interactions that radiate out from the PBC. The conformations of the phosphate binding cassettes containing two invariant arginine residues (Arg209 on domain A, and Arg333 on domain B) are somewhat different due to the sulfur interacting with this arginine. Furthermore, the B-site ligand together with the entire domain B show significant differences in their overall dynamic properties in the crystal structure of Delta(1-91) RIalpha complexed with (R(p))-cAMPS phosphothioate analogue ((R(p))-RIalpha) compared to the cAMP- and (S(p))-cAMPS-bound type I and II regulatory subunits, based on the temperature factors. In all structures, two structural solvent molecules exist within the A-site ligand binding pocket; both mediate water-bridged interactions between the ligand and the protein. No structured waters are in the B-site pocket. Owing to the higher resolution data, the N-terminal segment (109-117) of the RIalpha subunit can also be traced

AmpC-BETA Lactamases among Enterobacteriaceae Isolated at a Tertiary Hospital, South Western Uganda

PubMed Central

Nakaye, Martha; Bwanga, Freddie; Itabangi, Herbert; Stanley, Iramiot J.; Bashir, Mwambi; Bazira, Joel

2015-01-01

Aim To characterize AmpC-beta lactamases among Enterobacteriaceae isolates from clinical samples at Mbarara Regional Referral Hospital. Study Design Laboratory-based descriptive cross-sectional study Place and Duration of Study Microbiology Department, Mbarara Regional Referral Hospital and MBN clinical Laboratories, between May to September 2013. Methodology This study included 293 Enterobacteriaceae isolates recovered from clinical specimens that included blood, urine, stool and aspirates. AmpC Beta lactamase production was determined using disc placement method for cefoxitin at a break point of <18mm. Common AmpC plasmid mediated genes were EBC, ACC, FOX, DHA, CIT and MOX were; was determined by Multiplex PCR as described by Hanson and Perez-Perez. Results Plasmid mediated AmpC phenotype was confirmed in 107 of the 293 (36.5%) cefoxitin resistant isolates with 30 isolates having more than one gene coding for resistance. The commonest source that harbored AmpC beta lactamases was urine and E. coli was the most common AmpC producer (59.5%). The genotypes detected in this study, included EBC (n=36), FOX (n=18), ACC (n=11), CIT (n=10), DHA (n=07) and MOX (n=1). Conclusion Our findings showed that prevalence of AmpC beta-lactamase at MRRH was high (39.6), with EBC as the commonest genotype among Enterobacteriaceae Urine and E. coli were the commonest source and organism respectively that harbored AmpC beta-lactamases. There‘s rational antimicrobial therapy and antibiotic susceptibility tests should be requested by health workers especially patients presenting with urinary tract infections and bacteraemias. PMID:26078920

Study on multiple-hops performance of MOOC sequences-based optical labels for OPS networks

NASA Astrophysics Data System (ADS)

Zhang, Chongfu; Qiu, Kun; Ma, Chunli

2009-11-01

In this paper, we utilize a new study method that is under independent case of multiple optical orthogonal codes to derive the probability function of MOOCS-OPS networks, discuss the performance characteristics for a variety of parameters, and compare some characteristics of the system employed by single optical orthogonal code or multiple optical orthogonal codes sequences-based optical labels. The performance of the system is also calculated, and our results verify that the method is effective. Additionally it is found that performance of MOOCS-OPS networks would, negatively, be worsened, compared with single optical orthogonal code-based optical label for optical packet switching (SOOC-OPS); however, MOOCS-OPS networks can greatly enlarge the scalability of optical packet switching networks.

A large contribution of a cyclic AMP-independent pathway to turtle olfactory transduction

PubMed Central

1994-01-01

Although multiple pathways are involved in the olfactory transduction mechanism, cAMP-dependent pathway has been considered to contribute mainly to the transduction. We examined the degree of contribution of cAMP-independent pathway to the turtle olfactory response by recording inward currents from isolated cells, nerve impulses from cilia and olfactory bulbar responses. The results obtained by the three recordings were essentially consistent with each other, but detail studies were carried out by recording the bulbar response to obtain quantitative data. Application of an odorant cocktail to the isolated olfactory neuron after injection of 1 mM cAMP from the patch pipette elicited a large inward current. Mean amplitude of inward currents evoked by the cocktail with 1 mM cAMP in the patch pipette was similar to that without cAMP in the pipette. Application of the cocktail after the response to 50 microM forskolin was adapted also induced a large inward current. Application of the odorant cocktail to the olfactory epithelium, after the response to 50 microM forskolin was adapted, brought about an appreciable increase in the impulse frequency. The bulbar response to forskolin alone reached a saturation level around 10 microM. After the response to 50 microM forskolin was adapted, 11 species of odorants were applied to the olfactory epithelium. The magnitudes of responses to the odorants after forskolin were 45-80% of those of the control responses. There was no essential difference in the degree of the suppression by forskolin between cAMP- and IP3- producing odorants classified in the rat, suggesting that certain part of the forskolin-suppressive component was brought about by nonspecific action of forskolin. Application of a membrane permeant cAMP analogue, cpt-cAMP elicited a large response, and 0.1 mM citralva after 3 mM cpt- cAMP elicited 51% of the control response which was close to the response to citralva after 50 microM forskolin. A membrane permeant c

ChAMP: updated methylation analysis pipeline for Illumina BeadChips.

PubMed

Tian, Yuan; Morris, Tiffany J; Webster, Amy P; Yang, Zhen; Beck, Stephan; Feber, Andrew; Teschendorff, Andrew E

2017-12-15

The Illumina Infinium HumanMethylationEPIC BeadChip is the new platform for high-throughput DNA methylation analysis, effectively doubling the coverage compared to the older 450 K array. Here we present a significantly updated and improved version of the Bioconductor package ChAMP, which can be used to analyze EPIC and 450k data. Many enhanced functionalities have been added, including correction for cell-type heterogeneity, network analysis and a series of interactive graphical user interfaces. ChAMP is a BioC package available from https://bioconductor.org/packages/release/bioc/html/ChAMP.html. a.teschendorff@ucl.ac.uk or s.beck@ucl.ac.uk or a.feber@ucl.ac.uk. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

The MetOp second generation 3MI mission

NASA Astrophysics Data System (ADS)

Manolis, Ilias; Caron, Jérôme; Grabarnik, Semen; Bézy, Jean-Loup; Betto, Maurizio; Barré, Hubert; Mason, Graeme; Meynart, Roland

2017-11-01

ESA is currently running two parallel, competitive phase A/B1 studies for MetOp Second Generation (MetOp-SG). MetOp-SG is the space segment of EUMETSAT Polar System (EPS-SG) consisting of the satellites and instruments. The Phase A/B1 studies will be completed in the first quarter of 2013. The final implementation phases (B2/C/D) are planned to start 2013. ESA is responsible for instrument design of five missions, namely Microwave Sounding Mission (MWS), Scatterometer mission (SCA), Radio Occultation mission (RO), Microwave Imaging mission (MWI), Ice Cloud Imaging (ICI) mission, and Multiviewing, Multi-channel, Multi-polarization imaging mission (3MI). This paper will present the instrument main design elements of the 3MI mission, primarily aimed at providing aerosol characterization for climate monitoring, Numerical Weather Prediction (NWP), atmospheric chemistry and air quality. The 3MI instrument is a passive radiometer measuring the polarized radiances reflected by the Earth under different viewing geometries and across several spectral bands spanning the visible and short-wave infrared spectrum. The paper will present the main performances of the instrument and will concentrate mainly on the performance improvements with respect to its heritage derived by the POLDER instrument. The engineering of some key performance requirements (multiviewing, polarization sensitivity, etc.) will also be discussed.

ICS logging solution for network-based attacks using Gumistix technology

NASA Astrophysics Data System (ADS)

Otis, Jeremy R.; Berman, Dustin; Butts, Jonathan; Lopez, Juan

2013-05-01

Industrial Control Systems (ICS) monitor and control operations associated with the national critical infrastructure (e.g., electric power grid, oil and gas pipelines and water treatment facilities). These systems rely on technologies and architectures that were designed for system reliability and availability. Security associated with ICS was never an inherent concern, primarily due to the protections afforded by network isolation. However, a trend in ICS operations is to migrate to commercial networks via TCP/IP in order to leverage commodity benefits and cost savings. As a result, system vulnerabilities are now exposed to the online community. Indeed, recent research has demonstrated that many exposed ICS devices are being discovered using readily available applications (e.g., ShodanHQ search engine and Google-esque queries). Due to the lack of security and logging capabilities for ICS, most knowledge about attacks are derived from real world incidents after an attack has already been carried out and the damage has been done. This research provides a method for introducing sensors into the ICS environment that collect information about network-based attacks. The sensors are developed using an inexpensive Gumstix platform that can be deployed and incorporated with production systems. Data obtained from the sensors provide insight into attack tactics (e.g., port scans, Nessus scans, Metasploit modules, and zero-day exploits) and characteristics (e.g., attack origin, frequency, and level of persistence). Findings enable security professionals to draw an accurate, real-time awareness of the threats against ICS devices and help shift the security posture from reactionary to preventative.

TSH-induced cyclic AMP production in an ovine thyroid cell line: OVNIS 5H.

PubMed

Fayet, G; Aouani, A; Hovsépian, S

1986-01-06

The TSH-induced cyclic AMP response was studied using a 3-year-old ovine thyroid cell line TSH-independent for growth: OVNIS 5H. The kinetics of cyclic AMP production was followed both in cell layers and in cell culture media, with or without phosphodiesterase inhibitor. It is noteworthy that following the first wave in cyclic AMP obtained within minutes, we observed later a sustained exponential increase in cyclic AMP during the 5 days following TSH stimulation. A bioassay of TSH was derived allowing measurement of 1 microU/ml TSH from a crude bTSH preparation.

78 FR 1264 - CalAmp Wireless Networks Corporation, Waseca, MN; Notice of Negative Determination Regarding...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-08

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-81,646] CalAmp Wireless Networks...; CalAmp Wireless Networks Corporation, Waseca, Minnesota; expires on December 2, 2013). Conclusion Due to the eligibility of workers and former workers of CalAmp Wireless Networks Corporation, Waseca...

AMP Affects Intracellular Ca2+ Signaling, Migration, Cytokine Secretion and T Cell Priming Capacity of Dendritic Cells

PubMed Central

Panther, Elisabeth; Dürk, Thorsten; Ferrari, Davide; Di Virgilio, Francesco; Grimm, Melanie; Sorichter, Stephan; Cicko, Sanja; Herouy, Yared; Norgauer, Johannes; Idzko, Marco; Müller, Tobias

2012-01-01

The nucleotide adenosine-5′-monophosphate (AMP) can be released by various cell types and has been shown to elicit different cellular responses. In the extracellular space AMP is dephosphorylated to the nucleoside adenosine which can then bind to adenosine receptors. However, it has been shown that AMP can also activate A1 and A2a receptors directly. Here we show that AMP is a potent modulator of mouse and human dendritic cell (DC) function. AMP increased intracellular Ca2+ concentration in a time and dose dependent manner. Furthermore, AMP stimulated actin-polymerization in human DCs and induced migration of immature human and bone marrow derived mouse DCs, both via direct activation of A1 receptors. AMP strongly inhibited secretion of TNF-α and IL-12p70, while it enhanced production of IL-10 both via activation of A2a receptors. Consequently, DCs matured in the presence of AMP and co-cultivated with naive CD4+CD45RA+ T cells inhibited IFN-γ production whereas secretion of IL-5 and IL-13 was up-regulated. An enhancement of Th2-driven immune response could also be observed when OVA-pulsed murine DCs were pretreated with AMP prior to co-culture with OVA-transgenic naïve OTII T cells. An effect due to the enzymatic degradation of AMP to adenosine could be ruled out, as AMP still elicited migration and changes in cytokine secretion in bone-marrow derived DCs generated from CD73-deficient animals and in human DCs pretreated with the ecto-nucleotidase inhibitor 5′-(alpha,beta-methylene) diphosphate (APCP). Finally, the influence of contaminating adenosine could be excluded, as AMP admixed with adenosine desaminase (ADA) was still able to influence DC function. In summary our data show that AMP when present during maturation is a potent regulator of dendritic cell function and point out the role for AMP in the pathogenesis of inflammatory disorders. PMID:22624049

The CASE survey: Patient and physician perceptions regarding asthma medication use and associated oropharyngeal symptoms

PubMed Central

FitzGerald, J Mark; Chan, Charles KN; Holroyde, Martin C; Boulet, Louis-Philippe

2008-01-01

BACKGROUND: Oropharyngeal (OP) symptoms are common in asthma patients using inhaled corticosteroids (ICSs) alone and in combination with a long-acting beta2-agonist (LABA). Patterns of medication use, level of asthma control and association with OP symptoms are not often reported in a nonstudy setting. OBJECTIVES: To determine the prevalence of OP symptoms among adult asthma patients using ICSs alone and an ICS plus a LABA; to investigate the relationships between medication use, asthma control and OP symptoms; and to assess family physicians’ (FPs’) perceptions of the prevalence and management of OP symptoms. METHODS: A random telephone survey of 1003 asthma patients and 250 FPs treating asthma patients was conducted from February to March 2005 across Canada. RESULTS: Twenty-four per cent of patients experienced OP symptoms; 67% of them spoke to their FPs about the OP symptoms. Thirty-one per cent of patients who experienced OP symptoms stopped or reduced their dose of medication. OP symptoms were reported by 25% of patients using ICSs and 22% using an ICS plus a LABA. The incidence of OP symptoms was not affected by the choice of inhalation device (metered-dose inhaler versus dry powder inhaler) or the use of a spacer. Fifty-eight per cent of patients had uncontrolled asthma; patients achieving a lower level of general education were more likely to have poor control. Patients with uncontrolled asthma were more likely than those with controlled asthma to report OP symptoms (28% versus 18%, respectively; P<0.05). Eighty-nine per cent of FPs had patients who had reported OP symptoms to them. FPs estimated that 15% of their patients experienced OP symptoms and that compliance to treatment worsened in approximately 20% of them. CONCLUSIONS: The prevalence of OP symptoms in asthma patients using ICSs and an ICS plus a LABA is significant. OP symptoms were found to be associated with a reduced patient education level, with a likelihood of reducing or stopping

Sustained signalling by PTH modulates IP3 accumulation and IP3 receptors through cyclic AMP junctions

PubMed Central

Meena, Abha; Tovey, Stephen C.; Taylor, Colin W.

2015-01-01

ABSTRACT Parathyroid hormone (PTH) stimulates adenylyl cyclase through type 1 PTH receptors (PTH1R) and potentiates the Ca2+ signals evoked by carbachol, which stimulates formation of inositol 1,4,5-trisphosphate (IP3). We confirmed that in HEK cells expressing PTH1R, acute stimulation with PTH(1-34) potentiated carbachol-evoked Ca2+ release. This was mediated by locally delivered cyclic AMP (cAMP), but unaffected by inhibition of protein kinase A (PKA), exchange proteins activated by cAMP, cAMP phosphodiesterases (PDEs) or substantial inhibition of adenylyl cyclase. Sustained stimulation with PTH(1-34) causes internalization of PTH1R–adenylyl cyclase signalling complexes, but the consequences for delivery of cAMP to IP3R within cAMP signalling junctions are unknown. Here, we show that sustained stimulation with PTH(1-34) or with PTH analogues that do not evoke receptor internalization reduced the potentiated Ca2+ signals and attenuated carbachol-evoked increases in cytosolic IP3. Similar results were obtained after sustained stimulation with NKH477 to directly activate adenylyl cyclase, or with the membrane-permeant analogue of cAMP, 8-Br-cAMP. These responses were independent of PKA and unaffected by substantial inhibition of adenylyl cyclase. During prolonged stimulation with PTH(1-34), hyperactive cAMP signalling junctions, within which cAMP is delivered directly and at saturating concentrations to its targets, mediate sensitization of IP3R and a more slowly developing inhibition of IP3 accumulation. PMID:25431134

Gene Expression Patterns Define Key Transcriptional Events InCell-Cycle Regulation By cAMP And Protein Kinase A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zambon, Alexander C.; Zhang, Lingzhi; Minovitsky, Simon

Although a substantial number of hormones and drugs increase cellular cAMP levels, the global impact of cAMP and its major effector mechanism, protein kinase A (PKA), on gene expression is not known. Here we show that treatment of murine wild-type S49 lymphoma cells for 24 h with 8-(4-chlorophenylthio)-cAMP (8-CPTcAMP), a PKA-selective cAMP analog, alters the expression of approx equal to 4,500 of approx. equal to 13,600 unique genes. By contrast, gene expression was unaltered in Kin- S49 cells (that lack PKA) incubated with 8-CPTcAMP. Changes in mRNA and protein expression of several cell cycle regulators accompanied cAMP-induced G1-phase cell-cycle arrestmore » of wild-type S49 cells. Within 2h, 8-CPT-cAMP altered expression of 152 genes that contain evolutionarily conserved cAMP-response elements within 5 kb of transcriptional start sites, including the circadian clock gene Per1. Thus, cAMP through its activation of PKA produces extensive transcriptional regulation in eukaryotic cells. These transcriptional networks include a primary group of cAMP-response element-containing genes and secondary networks that include the circadian clock.« less

Enzymatic production of 5'-inosinic acid by AMP deaminase from a newly isolated Aspergillus oryzae.

PubMed

Li, Shubo; Chen, Leitao; Hu, Yangjun; Fang, Guohui; Zhao, Mouming; Guo, Yuan; Pang, Zongwen

2017-02-01

5'-adenylic acid deaminase (AMP deaminase), an important enzyme for the food industry, can catalyze the irreversible hydrolysis of adenosine monophosphate (AMP) to inosine monophosphate (IMP) and ammonia. In this study, a new strain was screened that efficiently produces 3191.6U/g of AMP deaminase at 32°C. After purification, the optimal temperature and pH of the AMP deaminase were found to be 40°C and 6.0, respectively, but it was partially inhibited by Fe(3+), Cu(2+), Al(3+), and Zn(2+). With amplification of the AMP deaminase production system, 6mL of crude enzyme could produce 2.00mg/g of IMP from 2.04mg/g of dried yeast with an 84.8% molar yield after 40min. These results provide a new insight into AMP deaminase production and offer a potential platform for producing 5'-IMP. Copyright © 2016 Elsevier Ltd. All rights reserved.

Earl Sutherland (1915-1974) [corrected] and the discovery of cyclic AMP.

PubMed

Blumenthal, Stanley A

2012-01-01

In 1945, Earl Sutherland (1915-1974) [corrected] and associates began studies of the mechanism of hormone-induced glycogen breakdown in the liver. In 1956, their efforts culminated in the identification of cyclic AMP, an ancient molecule generated in many cell types in response to hormonal and other extracellular signals. Cyclic AMP, the original "second messenger," transmits such signals through pathways that regulate a diversity of cellular functions and capabilities: metabolic processes such as lipolysis and glycogenolysis; hormone secretion; the permeability of ion channels; gene expression; cell proliferation and survival. Indeed, it can be argued that the discovery of cyclic AMP initiated the study of intracellular signaling pathways, a major focus of contemporary biomedical inquiry. This review presents relevant details of Sutherland's career; summarizes key contributions of his mentors, Carl and Gerti Cori, to the knowledge of glycogen metabolism (contributions that were the foundation for his own research); describes the experiments that led to his identification, isolation, and characterization of cyclic AMP; assesses the significance of his work; and considers some aspects of the impact of cyclic nucleotide research on clinical medicine.

A parallel input composite transimpedance amplifier.

PubMed

Kim, D J; Kim, C

2018-01-01

A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

A parallel input composite transimpedance amplifier

NASA Astrophysics Data System (ADS)

Kim, D. J.; Kim, C.

2018-01-01

A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

Development of brain injury criteria (BrIC).

PubMed

Takhounts, Erik G; Craig, Matthew J; Moorhouse, Kevin; McFadden, Joe; Hasija, Vikas

2013-11-01

Rotational motion of the head as a mechanism for brain injury was proposed back in the 1940s. Since then a multitude of research studies by various institutions were conducted to confirm/reject this hypothesis. Most of the studies were conducted on animals and concluded that rotational kinematics experienced by the animal's head may cause axonal deformations large enough to induce their functional deficit. Other studies utilized physical and mathematical models of human and animal heads to derive brain injury criteria based on deformation/pressure histories computed from their models. This study differs from the previous research in the following ways: first, it uses two different detailed mathematical models of human head (SIMon and GHBMC), each validated against various human brain response datasets; then establishes physical (strain and stress based) injury criteria for various types of brain injury based on scaled animal injury data; and finally, uses Anthropomorphic Test Devices (ATDs) (Hybrid III 50th Male, Hybrid III 5th Female, THOR 50th Male, ES-2re, SID-IIs, WorldSID 50th Male, and WorldSID 5th Female) test data (NCAP, pendulum, and frontal offset tests) to establish a kinematically based brain injury criterion (BrIC) for all ATDs. Similar procedures were applied to college football data where thousands of head impacts were recorded using a six degrees of freedom (6 DOF) instrumented helmet system. Since animal injury data used in derivation of BrIC were predominantly for diffuse axonal injury (DAI) type, which is currently an AIS 4+ injury, cumulative strain damage measure (CSDM) and maximum principal strain (MPS) were used to derive risk curves for AIS 4+ anatomic brain injuries. The AIS 1+, 2+, 3+, and 5+ risk curves for CSDM and MPS were then computed using the ratios between corresponding risk curves for head injury criterion (HIC) at a 50% risk. The risk curves for BrIC were then obtained from CSDM and MPS risk curves using the linear relationship

Of smuts, blasts, mildews, and blights: cAMP signaling in phytopathogenic fungi.

PubMed

Lee, Nancy; D'Souza, Cletus A; Kronstad, James W

2003-01-01

cAMP regulates morphogenesis and virulence in a wide variety of fungi including the plant pathogens. In saprophytic yeasts such as Saccharomyces cerevisiae, cAMP signaling plays an important role in nutrient sensing. In filamentous saprophytes, the cAMP pathway appears to play an integral role in vegetative growth and sporulation, with possible connections to mating. Infection-related morphogenesis includes sporulation (conidia and teliospores), formation of appressoria, infection hyphae, and sclerotia. Here, we review studies of cAMP signaling in a variety of plant fungal pathogens. The primary fungi to be considered include Ustilago maydis, Magnaporthe grisea, Cryphonectria parasitica, Colletotrichum and Fusarium species, and Erisyphe graminis. We also include related information on Trichoderma species that act as mycoparasites and biocontrol agents of phytopathogenic fungi. We point out similarities in infection mechanisms, conservation of signaling components, as well as instances of cross-talk with other signaling pathways.

IC-Finder: inferring robustly the hierarchical organization of chromatin folding

PubMed Central

Haddad, Noelle

2017-01-01

Abstract The spatial organization of the genome plays a crucial role in the regulation of gene expression. Recent experimental techniques like Hi-C have emphasized the segmentation of genomes into interaction compartments that constitute conserved functional domains participating in the maintenance of a proper cell identity. Here, we propose a novel method, IC-Finder, to identify interaction compartments (IC) from experimental Hi-C maps. IC-Finder is based on a hierarchical clustering approach that we adapted to account for the polymeric nature of chromatin. Based on a benchmark of realistic in silico Hi-C maps, we show that IC-Finder is one of the best methods in terms of reliability and is the most efficient numerically. IC-Finder proposes two original options: a probabilistic description of the inferred compartments and the possibility to explore the various hierarchies of chromatin organization. Applying the method to experimental data in fly and human, we show how the predicted segmentation may depend on the normalization scheme and how 3D compartmentalization is tightly associated with epigenomic information. IC-Finder provides a robust and generic ‘all-in-one’ tool to uncover the general principles of 3D chromatin folding and their influence on gene regulation. The software is available at http://membres-timc.imag.fr/Daniel.Jost/DJ-TIMC/Software.html. PMID:28130423

Maximization of transcription of the serC (pdxF)-aroA multifunctional operon by antagonistic effects of the cyclic AMP (cAMP) receptor protein-cAMP complex and Lrp global regulators of Escherichia coli K-12.

PubMed

Man, T K; Pease, A J; Winkler, M E

1997-06-01

The arrangement of the Escherichia coli serC (pdxF) and aroA genes into a cotranscribed multifunctional operon allows coregulation of two enzymes required for the biosynthesis of L-serine, pyridoxal 5'-phosphate, chorismate, and the aromatic amino acids and vitamins. RNase T2 protection assays revealed two major transcripts that were initiated from a promoter upstream from serC (pdxF). Between 80 to 90% of serC (pdxF) transcripts were present in single-gene mRNA molecules that likely arose by Rho-independent termination between serC (pdxF) and aroA. serC (pdxF)-aroA cotranscripts terminated at another Rho-independent terminator near the end of aroA. We studied operon regulation by determining differential rates of beta-galactosidase synthesis in a merodiploid strain carrying a single-copy lambda[phi(serC [pdxF]'-lacZYA)] operon fusion. serC (pdxF) transcription was greatest in bacteria growing in minimal salts-glucose medium (MMGlu) and was reduced in minimal salts-glycerol medium, enriched MMGlu, and LB medium. serC (pdxF) transcription was increased in cya or crp mutants compared to their cya+ crp+ parent in MMGlu or LB medium. In contrast, serC (pdxF) transcription decreased in an lrp mutant compared to its lrp+ parent in MMGlu. Conclusions obtained by using the operon fusion were corroborated by quantitative Western immunoblotting of SerC (PdxF), which was present at around 1,800 dimers per cell in bacteria growing in MMGlu. RNase T2 protection assays of serC (pdxF)-terminated and serC (pdxF)-aroA cotranscript amounts supported the conclusion that the operon was regulated at the transcription level under the conditions tested. Results with a series of deletions upstream of the P(serC (pdxF)) promoter revealed that activation by Lrp was likely direct, whereas repression by the cyclic AMP (cAMP) receptor protein-cAMP complex (CRP-cAMP) was likely indirect, possibly via a repressor whose amount or activity was stimulated by CRP-cAMP.

Cyclic AMP and alkaline pH downregulate carbonic anhydrase 2 in mouse fibroblasts.

PubMed

Mardones, Pablo; Chang, Jung Chin; Oude Elferink, Ronald P J

2014-06-01

The hydration of CO2 catalyzed by the ubiquitous carbonic anhydrase 2 (Ca2) is central for bicarbonate transport, bone metabolism and acid-base homeostasis in metazoans. There is evidence that in some tissues Ca2 expression can be acutely induced by cAMP, whereas in other cell types it is unresponsive to cAMP-mediated transcriptional activation. We isolated fibroblasts from wild type and mice lacking the ubiquitous chloride/bicarbonate exchanger (Ae2a,b(-/-) mice). In these cells the regulation of carbonic anhydrase 2 by cAMP was studied. We show that Ca2 expression is strongly inhibited by chronic incubation with dibutyryl-cAMP, forskolin or alkaline pH in cultured mouse fibroblasts. Furthermore, fibroblasts obtained from anion exchanger 2 deficient (Ae2a,b(-/-)) mice, which display intracellular alkalosis and increased cAMP production, express less than 10% of control Ca2 mRNA and protein. Surprisingly, inhibition of the bicarbonate-sensitive soluble adenylyl cyclase (sAC) was found to reduce CA2 expression instead of increasing it. CA2 expression is strongly regulated by intracellular pH and by cAMP, suggesting a role for soluble adenylyl cyclase. Regulation occurs in opposite directions which may be explained by an incoherent feedforward loop consisting of activation by pCREB and repression by ICER. Copyright © 2013 Elsevier B.V. All rights reserved.

Lipopolysaccharide and cAMP modify placental calcitriol biosynthesis reducing antimicrobial peptides gene expression.

PubMed

Olmos-Ortiz, Andrea; García-Quiroz, Janice; Avila, Euclides; Caldiño-Soto, Felipe; Halhali, Ali; Larrea, Fernando; Díaz, Lorenza

2018-06-01

Calcitriol, the hormonal form of vitamin D 3 (VD), stimulates placental antimicrobial peptides expression; nonetheless, the regulation of calcitriol biosynthesis in the presence of bacterial products and its consequence on placental innate immunity have scarcely been addressed. We investigated how some bacterial products modify placental VD metabolism and its ability to induce antimicrobial peptides gene expression. Cultured human trophoblasts biosynthesized calcitriol only in the presence of its precursor calcidiol, a process that was inhibited by cyclic-AMP but stimulated by lipopolysaccharide (LPS). Intracrine calcitriol upregulated cathelicidin, S100A9, and β-defensins (HBDs) gene expression, while LPS further stimulated HBD2 and S100A9. Unexpectedly, LPS significantly repressed cathelicidin basal mRNA levels and drastically diminished calcidiol ability to induce it. Meanwhile, cyclic-AMP, which is used by many microbes to avoid host defenses, suppressed calcitriol biosynthesis, resulting in significant inhibition of most VD-dependent microbicidal peptides gene expression. While LPS stimulated calcitriol biosynthesis, cyclic-AMP inhibited it. LPS downregulated cathelicidin mRNA expression, whereas cyclic-AMP antagonized VD-dependent-upregulation of most antimicrobial peptides. These findings reveal LPS and cyclic-AMP involvement in dampening placental innate immunity, highlighting the importance of cyclic-AMP in the context of placental infection and suggesting its participation to facilitate bacterial survival. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Unified study of Quality of Service (QoS) in OPS/OBS networks

NASA Astrophysics Data System (ADS)

Hailu, Dawit Hadush; Lema, Gebrehiwet Gebrekrstos; Yekun, Ephrem Admasu; Kebede, Samrawit Haylu

2017-07-01

With the growth of Internet traffic, an inevitable use of optical networks provide a large bandwidth, fast data transmission rates and Quality of Service (QoS) support. Currently, Optical Burst Switched (OBS)/Optical Packet Switched (OPS) networks are under study as future solutions for addressing the increase demand of Internet traffic. However, due to their high blocking probability in the intermediate nodes they have been delayed in the industries. Packet loss in OBS/OPS networks is mainly occur due to contention. Hence, the contribution of this study is to analyze the file loss ratio (FLR), packet overhead and number of disjoint paths, and processing delay over Coded Packet Transport (CPT) scheme for OBS/OPS network using simulation. The simulations show that CPT scheme reduces the FLR in OBS/OPS network for the evaluated scenarios since the data packets are chopped off into blocks of the data packet for transmission over a network. Simulation results for secrecy and survivability are verified with the help of the analytical model to define the operational range of CPT scheme.

Hubble Space Telescope Image: Planetary Nebula IC 4406

NASA Technical Reports Server (NTRS)

2001-01-01

This Hubble Space Telescope image reveals a rainbow of colors in this dying star, called IC 446. Like many other so-called planetary nebulae, IC 4406 exhibits a high degree of symmetry. The nebula's left and right halves are nearly mirror images of the other. If we could fly around IC 446 in a spaceship, we would see that the gas and dust form a vast donut of material streaming outward from the dying star. We do not see the donut shape in this photograph because we are viewing IC 4406 from the Earth-orbiting HST. From this vantage point, we are seeing the side of the donut. This side view allows us to see the intricate tendrils of material that have been compared to the eye's retina. In fact, IC 4406 is dubbed the 'Retina Nebula.' The donut of material confines the intense radiation coming from the remnant of the dying star. Gas on the inside of the donut is ionized by light from the central star and glows. Light from oxygen atoms is rendered blue in this image; hydrogen is shown as green, and nitrogen as red. The range of color in the final image shows the differences in concentration of these three gases in the nebula. This image is a composite of data taken by HST's Wide Field Planetary Camera 2 in June 2001 and in January 2002 by Bob O'Dell (Vanderbilt University) and collaborators, and in January by the Hubble Heritage Team (STScI). Filters used to create this color image show oxygen, hydrogen, and nitrogen gas glowing in this object.

Epac2 Mediates cAMP-Dependent Potentiation of Neurotransmission in the Hippocampus

PubMed Central

Fernandes, Herman B.; Riordan, Sean; Nomura, Toshihiro; Remmers, Christine L.; Kraniotis, Stephen; Marshall, John J.; Kukreja, Lokesh; Vassar, Robert

2015-01-01

Presynaptic terminal cAMP elevation plays a central role in plasticity at the mossy fiber-CA3 synapse of the hippocampus. Prior studies have identified protein kinase A as a downstream effector of cAMP that contributes to mossy fiber LTP (MF-LTP), but the potential contribution of Epac2, another cAMP effector expressed in the MF synapse, has not been considered. We investigated the role of Epac2 in MF-CA3 neurotransmission using Epac2−/− mice. The deletion of Epac2 did not cause gross alterations in hippocampal neuroanatomy or basal synaptic transmission. Synaptic facilitation during short trains was not affected by loss of Epac2 activity; however, both long-term plasticity and forskolin-mediated potentiation of MFs were impaired, demonstrating that Epac2 contributes to cAMP-dependent potentiation of transmitter release. Examination of synaptic transmission during long sustained trains of activity suggested that the readily releasable pool of vesicles is reduced in Epac2−/− mice. These data suggest that cAMP elevation uses an Epac2-dependent pathway to promote transmitter release, and that Epac2 is required to maintain the readily releasable pool at MF synapses in the hippocampus. PMID:25904804

Epac2 Mediates cAMP-Dependent Potentiation of Neurotransmission in the Hippocampus.

PubMed

Fernandes, Herman B; Riordan, Sean; Nomura, Toshihiro; Remmers, Christine L; Kraniotis, Stephen; Marshall, John J; Kukreja, Lokesh; Vassar, Robert; Contractor, Anis

2015-04-22

Presynaptic terminal cAMP elevation plays a central role in plasticity at the mossy fiber-CA3 synapse of the hippocampus. Prior studies have identified protein kinase A as a downstream effector of cAMP that contributes to mossy fiber LTP (MF-LTP), but the potential contribution of Epac2, another cAMP effector expressed in the MF synapse, has not been considered. We investigated the role of Epac2 in MF-CA3 neurotransmission using Epac2(-/-) mice. The deletion of Epac2 did not cause gross alterations in hippocampal neuroanatomy or basal synaptic transmission. Synaptic facilitation during short trains was not affected by loss of Epac2 activity; however, both long-term plasticity and forskolin-mediated potentiation of MFs were impaired, demonstrating that Epac2 contributes to cAMP-dependent potentiation of transmitter release. Examination of synaptic transmission during long sustained trains of activity suggested that the readily releasable pool of vesicles is reduced in Epac2(-/-) mice. These data suggest that cAMP elevation uses an Epac2-dependent pathway to promote transmitter release, and that Epac2 is required to maintain the readily releasable pool at MF synapses in the hippocampus. Copyright © 2015 the authors 0270-6474/15/356544-10$15.00/0.

Reproducible and sustained regulation of Gαs signalling using a metazoan opsin as an optogenetic tool.

PubMed

Bailes, Helena J; Zhuang, Ling-Yu; Lucas, Robert J

2012-01-01

Originally developed to regulate neuronal excitability, optogenetics is increasingly also used to control other cellular processes with unprecedented spatiotemporal resolution. Optogenetic modulation of all major G-protein signalling pathways (Gq, Gi and Gs) has been achieved using variants of mammalian rod opsin. We show here that the light response driven by such rod opsin-based tools dissipates under repeated exposure, consistent with the known bleaching characteristics of this photopigment. We continue to show that replacing rod opsin with a bleach resistant opsin from Carybdea rastonii, the box jellyfish, (JellyOp) overcomes this limitation. Visible light induced high amplitude, reversible, and reproducible increases in cAMP in mammalian cells expressing JellyOp. While single flashes produced a brief cAMP spike, repeated stimulation could sustain elevated levels for 10s of minutes. JellyOp was more photosensitive than currently available optogenetic tools, responding to white light at irradiances ≥1 µW/cm(2). We conclude that JellyOp is a promising new tool for mimicking the activity of Gs-coupled G protein coupled receptors with fine spatiotemporal resolution.

A simple electrostatic switch important in the activation of type I protein kinase A by cyclic AMP.

PubMed

Vigil, Dominico; Lin, Jung-Hsin; Sotriffer, Christoph A; Pennypacker, Juniper K; McCammon, J Andrew; Taylor, Susan S

2006-01-01

Cyclic AMP activates protein kinase A by binding to an inhibitory regulatory (R) subunit and releasing inhibition of the catalytic (C) subunit. Even though crystal structures of regulatory and catalytic subunits have been solved, the precise molecular mechanism by which cyclic AMP activates the kinase remains unknown. The dynamic properties of the cAMP binding domain in the absence of cAMP or C-subunit are also unknown. Here we report molecular-dynamics simulations and mutational studies of the RIalpha R-subunit that identify the C-helix as a highly dynamic switch which relays cAMP binding to the helical C-subunit binding regions. Furthermore, we identify an important salt bridge which links cAMP binding directly to the C-helix that is necessary for normal activation. Additional mutations show that a hydrophobic "hinge" region is not as critical for the cross-talk in PKA as it is in the homologous EPAC protein, illustrating how cAMP can control diverse functions using the evolutionarily conserved cAMP-binding domains.

Comparative Effects of Angiotensin and ACTH on Cyclic AMP and Steroidogenesis in Isolated Bovine Adrenal Cells

PubMed Central

Peytremann, Andre; Nicholson, Wendell E.; Brown, Ronald D.; Liddle, Grant W.; Hardman, Joel G.

1973-01-01

The comparative effects of angiotensin II and adrenocorticotropic hormone (ACTH) on cyclic AMP and steroidogenesis were investigated employing isolated bovine adrenal cells from the zona fasciculata. Like ACTH, angiotensin produced a prompt increase in cyclic AMP which preceded the increase in corticosteroid production. Although this increase in cyclic AMP was small when compared to that induced by ACTH, it correlated with the amount of steroidogenesis. This observation is consistent with the view that cyclic AMP is the intracellular mediator of the steroidogenic action of angiotensin. Angiotensin acted synergistically with ACTH on cyclic AMP levels. This synergism was not explained by inhibition of phosphodiesterase activity. Unlike ACTH, angiotensin failed to stimulate adenylate cyclase in broken cell preparations. The observations suggest that more than one mechanism may be involved in effects of ACTH and angiotensin on cyclic AMP levels. PMID:4348344

Epidemiology of extended-spectrum β-lactamase, AmpC, and carbapenemase production in Proteus mirabilis.

PubMed

Datta, Priya; Gupta, Varsha; Arora, Shilpa; Garg, Shivani; Chander, Jagdish

2014-01-01

Proteus mirabilis strains that produce extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, and carbapenemase pose potential threats to patient care because most clinical diagnostic laboratories may not attempt to detect these three major groups of enzymes. Therefore, the objective of this study was to ascertain if P. mirabilis isolates collected from our heathcare facility possess various mechanisms of resistance to β-lactams (i.e., ESBL, AmpC, and carbapenemases) and to additionally arrive at conclusions regarding concurrent testing for these three mechanism of drug resistance in order to reduce cost and time in routine diagnostic testing. Between January 2011 and June 2011, 60 consecutive non-repeated strains of P. mirabilis were evaluated for production of ESBLs, AmpC β-lactamases, and carbapenemases. Of these, 36 isolates were found to be ESBL producers, and 7 (12%) were positive for production of AmpC β-lactamases and ESBLs. Therefore, 19.4% of ESBL-producing Proteus strains coproduced AmpC enzymes. The modified Hodge test confirmed carbapenemase production in only 1 isolate (1.7%), which was also ESBL- and AmpC-positive. The clinical impact of additional AmpC expression in ESBL-producing P. mirabilis results in a newly acquired resistance to β-lactamase inhibitors. In addition, to save time and costs, we recommend the use of cefepime/cefepime-clavulanate or boronic acid for the ESBL detection but in only those strains that were positive for ESBL by screening and negative by confirmatory tests.

Measurement of cAMP in an undergraduate teaching laboratory, using ALPHAscreen technology.

PubMed

Bartho, Joseph D; Ly, Kien; Hay, Debbie L

2012-02-14

Adenosine 3',5'-monophosphate (cAMP) is a cellular second messenger with central relevance to pharmacology, cell biology, and biochemistry teaching programs. cAMP is produced from adenosine triphosphate by adenylate cyclase, and its production is reduced or enhanced upon activation of many G protein-coupled receptors. Therefore, the measurement of cAMP serves as an indicator of receptor activity. Although there are many assays available for measuring cAMP, few are suitable for large class teaching, and even fewer seem to have been adapted for this purpose. Here, we describe the use of bead-based ALPHAscreen (Amplified Luminescent Proximity Homogenous Assay) technology for teaching a class of more than 300 students the practical aspects of detecting signal transduction. This technology is applicable to the measurement of many different signaling pathways. This resource is designed to provide a practical guide for instructors and a useful model for developing other classes using similar technologies.

Dibutyryl cyclic AMP induces differentiation of human neuroblastoma SH-SY5Y cells into a noradrenergic phenotype.

PubMed

Kume, Toshiaki; Kawato, Yuka; Osakada, Fumitaka; Izumi, Yasuhiko; Katsuki, Hiroshi; Nakagawa, Takayuki; Kaneko, Shuji; Niidome, Tetsuhiro; Takada-Takatori, Yuki; Akaike, Akinori

2008-10-10

Dibutyryl cyclic AMP (dbcAMP) and retinoic acid (RA) have been demonstrated to be the inducers of morphological differentiation in SH-SY5Y cells, a human catecholaminergic neuroblastoma cell line. However, it remains unclear whether morphologically differentiated SH-SY5Y cells by these compounds acquire catecholaminergic properties. We focused on the alteration of tyrosine hydroxylase (TH) expression and intracellular content of noradrenaline (NA) as the indicators of functional differentiation. Three days treatment with dbcAMP (1mM) and RA (10microM) induced morphological changes and an increase of TH-positive cells using immunocytochemical analysis in SH-SY5Y cells. The percentage of TH-expressing cells in dbcAMP (1mM) treatment was larger than that in RA (10microM) treatment. In addition, dbcAMP increased intracellular NA content, whereas RA did not. The dbcAMP-induced increase in TH-expressing cells is partially inhibited by KT5720, a protein kinase A (PKA) inhibitor. We also investigated the effect of butyrate on SH-SY5Y cells, because dbcAMP is enzymatically degraded by intracellular esterase, thereby resulting in the formation of butyrate. Butyrate induced the increase of NA content at lower concentrations than dbcAMP, although the increase in TH-expressing cells by butyrate was smaller than that by dbcAMP. The dbcAMP (1mM)- and butyrate (0.3mM)-induced increase in NA content was completely suppressed by alpha-methyl-p-tyrosine (1mM), an inhibitor of TH. These results suggest that dbcAMP induces differentiation into the noradrenergic phenotype through both PKA activation and butyrate.

30 CFR 57.22104 - Open flames (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Open flames (I-C mines). 57.22104 Section 57... Standards for Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22104 Open flames (I-C mines). (a) Open flames, including cutting and welding, shall not be used underground. (b) Welding and...

30 CFR 57.22104 - Open flames (I-C mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Open flames (I-C mines). 57.22104 Section 57... Standards for Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22104 Open flames (I-C mines). (a) Open flames, including cutting and welding, shall not be used underground. (b) Welding and...

30 CFR 57.22104 - Open flames (I-C mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Open flames (I-C mines). 57.22104 Section 57... Standards for Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22104 Open flames (I-C mines). (a) Open flames, including cutting and welding, shall not be used underground. (b) Welding and...

30 CFR 57.22104 - Open flames (I-C mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Open flames (I-C mines). 57.22104 Section 57... Standards for Methane in Metal and Nonmetal Mines Fire Prevention and Control § 57.22104 Open flames (I-C mines). (a) Open flames, including cutting and welding, shall not be used underground. (b) Welding and...

Lithium Abundances in the Young Open Cluster IC 2602

NASA Technical Reports Server (NTRS)

Randich, S.; Aharpour, N.; Pallavicini, R.; Prosser, C. F.; Stauffer, J. R.

1997-01-01

We have obtained high-resolution spectra for 28 candidate late-type stars in the 30 Myr old cluster IC 2602. NLTE Li abundances have been derived from measured equivalent widths. The log n(Li) - T(sub eff) and log n(Li) - mass distributions for our sample stars have been compared with those of the Pleiades and alpha Persei. Our data show that F stars in the three clusters have the same lithium content, which corresponds to the initial content for Pop. I stars. G and early-K IC 2602 stars are, on average, somewhat more Li-rich than their counterparts in the two slightly older clusters. Finally, the latest-type IC 2602 stars are heavily Li depleted, with their Li content being as low as the lowest measured among the Pleiades. As in the Pleiades and alpha Per, a star-to-star scatter in lithium is observed among 30 Myr old late-K/early-K dwarfs in IC 2602, indicating that this spread develops in the pre-main sequence phases.

Co-Occurrence of Plasmid-Mediated AmpC β-Lactamase Activity Among Klebsiella pneumoniae and Escherichia Coli

PubMed Central

Zorgani, Abdulaziz; Daw, Hiyam; Sufya, Najib; Bashein, Abdullah; Elahmer, Omar; Chouchani, Chedly

2017-01-01

Introduction: Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. Objective: The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. Methods: All clinical isolates (76 K. pneumoniae and 75 E. coli) collected over two years (2013-2014) were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL and AmpC phenotype using E-test and ESBL and AmpC screen disc test. Both ESBL and AmpC-positive isolates were then screened for the presence of genes encoding plasmid-mediated AmpC β-lactamases by polymerase chain reaction (PCR). Results: Of the K. pneumoniae and E. coli tested, 75% and 16% were resistant to gentamicin, 74% and 1.3% to imipenem, 71% and 12% to cefoxitin, 80% and 12% to cefepime, 69% and 22.6% to ciprofloxacin, respectively. None of the E. coli isolates were multidrug resistant compared with K. pneumoniae (65.8%). K. pneumoniae ESBL producers were significantly higher (85.5%) compared with (17.3%) E. coli isolates (P <0.0001, OR=4.93). Plasmid-mediated AmpC genes were detected in 7.9% of K. pneumoniae, and 4% E. coli isolates. There was low agreement between phenotypic and genotypic methods, phenotypic testing underestimated detection of AmpC enzyme and did not correlate well with molecular results. The gene encoding CMY enzyme was the most prevalent (66.6%) of AmpC positive isolates followed by MOX, DHA and EBC. Only one AmpC gene was detected in 5/9 isolates, i.e, blaCMY (n=3), bla MOX (n=1), blaDHA (n=1). However, co-occurrence of AmpC genes were evident in 3/9 isolates with the following distribution: bla CMY and blaEBC (n=1), and blaCMY and blaMOX (n=2). Neither blaFOX nor blaACC was detected in all tested isolates. All AmpC positive strains were resistant to cefoxitin and isolated from patients admitted to

Co-Occurrence of Plasmid-Mediated AmpC β-Lactamase Activity Among Klebsiella pneumoniae and Escherichia Coli.

PubMed

Zorgani, Abdulaziz; Daw, Hiyam; Sufya, Najib; Bashein, Abdullah; Elahmer, Omar; Chouchani, Chedly

2017-01-01

Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. All clinical isolates (76 K. pneumoniae and 75 E. coli ) collected over two years (2013-2014) were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL and AmpC phenotype using E-test and ESBL and AmpC screen disc test. Both ESBL and AmpC-positive isolates were then screened for the presence of genes encoding plasmid-mediated AmpC β-lactamases by polymerase chain reaction (PCR). Of the K. pneumoniae and E. coli tested, 75% and 16% were resistant to gentamicin, 74% and 1.3% to imipenem, 71% and 12% to cefoxitin, 80% and 12% to cefepime, 69% and 22.6% to ciprofloxacin, respectively. None of the E. coli isolates were multidrug resistant compared with K. pneumoniae (65.8%). K. pneumoniae ESBL producers were significantly higher (85.5%) compared with (17.3%) E. coli isolates (P <0.0001, OR=4.93). Plasmid-mediated AmpC genes were detected in 7.9% of K. pneumoniae , and 4% E. coli isolates. There was low agreement between phenotypic and genotypic methods, phenotypic testing underestimated detection of AmpC enzyme and did not correlate well with molecular results. The gene encoding CMY enzyme was the most prevalent (66.6%) of AmpC positive isolates followed by MOX, DHA and EBC. Only one AmpC gene was detected in 5/9 isolates, i.e, bla CMY (n=3), bla MOX (n=1), bla DHA (n=1). However, co-occurrence of AmpC genes were evident in 3/9 isolates with the following distribution: bla CMY and bla EBC (n=1), and bla CMY and bla MOX (n=2). Neither bla FOX nor bla ACC was detected in all tested isolates. All AmpC positive strains were resistant to cefoxitin and isolated from patients admitted to intensive care units. Further studies are

ASASSN-16fp (SN 2016coi): a transitional supernova between Type Ic and broad-lined Ic

NASA Astrophysics Data System (ADS)

Kumar, Brajesh; Singh, A.; Srivastav, S.; Sahu, D. K.; Anupama, G. C.

2018-01-01

We present results based on a well-sampled optical (UBVRI) and ultraviolet (Swift/UVOT) imaging, and low-resolution optical spectroscopic follow-up observations of the nearby Type Ic supernova (SN) ASASSN-16fp (SN 2016coi). The SN was monitored during the photospheric phase (-10 to +33 d with respect to the B-band maximum light). The rise to maximum light and early post-maximum decline of the light curves are slow. The peak absolute magnitude (MV = -17.7 ± 0.2 mag) of ASASSN-16fp is comparable with broad-lined Ic SN 2002ap, SN 2012ap and transitional Ic SN 2004aw but considerably fainter than the gamma-ray burst/X-ray flash associated SNe (e.g. SN 1998bw, 2006aj). Similar to the light curve, the spectral evolution is also slow. ASASSN-16fp shows distinct photospheric phase spectral lines along with the C II features. The expansion velocity of the ejecta near maximum light reached ∼16 000 km s-1 and settled to ∼8000 km s-1, ∼1 month post-maximum. Analytical modelling of the quasi-bolometric light curve of ASASSN-16fp suggests that ∼0.1 M⊙ 56Ni mass was synthesized in the explosion, with a kinetic energy of 6.9^{+1.5}_{-1.3} × 1051 erg and total ejected mass of ∼4.5 ± 0.3 M⊙.

Study on Mine Emergency Mechanism based on TARP and ICS

NASA Astrophysics Data System (ADS)

Xi, Jian; Wu, Zongzhi

2018-01-01

By analyzing the experiences and practices of mine emergency in China and abroad, especially the United States and Australia, normative principle, risk management principle and adaptability principle of constructing mine emergency mechanism based on Trigger Action Response Plans (TARP) and Incident Command System (ICS) are summarized. Classification method, framework, flow and subject of TARP and ICS which are suitable for the actual situation of domestic mine emergency are proposed. The system dynamics model of TARP and ICS is established. The parameters such as evacuation ratio, response rate, per capita emergency capability and entry rate of rescuers are set up. By simulating the operation process of TARP and ICS, the impact of these parameters on the emergency process are analyzed, which could provide a reference and basis for building emergency capacity, formulating emergency plans and setting up action plans in the emergency process.

Droplet-Wall/Film Impact in IC Engine Applications

DTIC Science & Technology

2017-08-14

Report: Droplet-Wall/Film Impact in IC Engine Applications (ARO Topic 1.4.1 under ARO’s Dr. Ralph A. Anthenien) The views, opinions and/or findings...in IC Engine Applications (ARO Topic 1.4.1 under ARO’s Dr. Ralph A. Anthenien) Report Term: 0-Other Email: cklaw@princeton.edu Distribution Statement...associated with spraying in internal combustion engines (ICEs). Fuels sprayed inside engines can impact with the internal surfaces and thus not only

Nuclease-resistant c-di-AMP derivatives that differentially recognize RNA and protein receptors

PubMed Central

Meehan, Robert E.; Torgerson, Chad D.; Gaffney, Barbara L.; Jones, Roger A.; Strobel, Scott A.

2016-01-01

The ability of bacteria to sense environmental cues and adapt is essential for their survival. The use of second-messenger signaling molecules to translate these cues into a physiological response is a common mechanism employed by bacteria. The second messenger 3’-5’-cyclic diadenosine monophosphate (c-di-AMP) has been linked to a diverse set of biological processes involved in maintaining cell viability and homeostasis, as well as pathogenicity. A complex network of both protein and RNA receptors inside the cell activate specific pathways and mediate phenotypic outputs in response to c-di-AMP. Structural analysis of these RNA and protein receptors has revealed the different recognition elements employed by these effectors to bind the same small molecule. Herein, using a series of c-di-AMP analogs, we probed the interactions made with a riboswitch and a phosphodiesterase protein to identify the features important for c-di-AMP binding and recognition. We found that the ydaO riboswitch binds c-di-AMP in two discrete sites with near identical affinity and a Hill coefficient of 1.6. The ydaO riboswitch distinguishes between c-di-AMP and structurally related second messengers by discriminating against an amine at the C2 position, more than a carbonyl at the C6 position. We also identified phosphate-modified analogs that bind both the ydaO RNA and GdpP protein with high affinity, while symmetrically-modified ribose analogs exhibited a substantial decrease in ydaO affinity, but retained high affinity for GdpP. These ligand modifications resulted in increased resistance to enzyme-catalyzed hydrolysis by the GdpP enzyme. Together, these data suggest that these c-di-AMP analogs could be useful as chemical tools to specifically target subsections of the second-messenger signaling pathways. PMID:26789423

cAMP-Signalling Regulates Gametocyte-Infected Erythrocyte Deformability Required for Malaria Parasite Transmission

PubMed Central

Thompson, Eloise; Breil, Florence; Lorthiois, Audrey; Dupuy, Florian; Cummings, Ross; Duffier, Yoann; Corbett, Yolanda; Mercereau-Puijalon, Odile; Vernick, Kenneth; Taramelli, Donatella; Baker, David A.; Langsley, Gordon; Lavazec, Catherine

2015-01-01

Blocking Plasmodium falciparum transmission to mosquitoes has been designated a strategic objective in the global agenda of malaria elimination. Transmission is ensured by gametocyte-infected erythrocytes (GIE) that sequester in the bone marrow and at maturation are released into peripheral blood from where they are taken up during a mosquito blood meal. Release into the blood circulation is accompanied by an increase in GIE deformability that allows them to pass through the spleen. Here, we used a microsphere matrix to mimic splenic filtration and investigated the role of cAMP-signalling in regulating GIE deformability. We demonstrated that mature GIE deformability is dependent on reduced cAMP-signalling and on increased phosphodiesterase expression in stage V gametocytes, and that parasite cAMP-dependent kinase activity contributes to the stiffness of immature gametocytes. Importantly, pharmacological agents that raise cAMP levels in transmissible stage V gametocytes render them less deformable and hence less likely to circulate through the spleen. Therefore, phosphodiesterase inhibitors that raise cAMP levels in P. falciparum infected erythrocytes, such as sildenafil, represent new candidate drugs to block transmission of malaria parasites. PMID:25951195

[Occurrence of AmpC-positive Klebsiella pneumoniae strains in patients with haematological malignancies].

PubMed

Chromá, Magdaléna; Kolár, Milan; Sauer, Pavel; Faber, Edgar; Stosová, Tatána; Koukalová, Dagmar; Indrák, Karel

2008-10-01

Currently, important bacterial beta-lactamases of increasing clinical significance include AmpC enzymes. The aim was to assess their occurrence in Klebsiella pneumoniae strains isolated from patients with haematological malignancies in a prospective study. Over a 2-month period, strains of the species were isolated from clinical material obtained from patients hospitalized at the Department of Haemato-Oncology of the University Hospital Olomouc. The strains were identified using standard microbiological techniques and the Vitek 2 automated system. Production of AmpC beta-lactamases was roughly determined by phenotypic tests and subsequently confirmed by PCR detection of genes encoding these enzymes. During the above-mentioned period, a total of 35 K. pneumoniae isolates were collected. In 7 of them, production of AmpC beta-lactamases was preliminarily detected by phenotypic test. The multiplex PCR method confirmed phenotyping and determined DHA types in all the isolates. All AmpC-positive isolates were false-susceptible to at least one of the tested third-generation cephalosporins. In one patient, clinically apparent infection caused by this strain was documented. The reported results suggest the possibility of occurrence of AmpC-beta-lactamases in K. pneumoniae strains with clinical significance.

IT Software Development and IT Operations Strategic Alignment: An Agile DevOps Model

ERIC Educational Resources Information Center

Hart, Michael

2017-01-01

Information Technology (IT) departments that include development and operations are essential to develop software that meet customer needs. DevOps is a term originally constructed from software development and IT operations. DevOps includes the collaboration of all stakeholders such as software engineers and systems administrators involved in the…

Interaction of 2',3'-cAMP with Rbp47b Plays a Role in Stress Granule Formation.

PubMed

Kosmacz, Monika; Luzarowski, Marcin; Kerber, Olga; Leniak, Ewa; Gutiérrez-Beltrán, Emilio; Moreno, Juan Camilo; Gorka, Michał; Szlachetko, Jagoda; Veyel, Daniel; Graf, Alexander; Skirycz, Aleksandra

2018-05-01

2',3'-cAMP is an intriguing small molecule that is conserved among different kingdoms. 2',3'-cAMP is presumably produced during RNA degradation, with increased cellular levels observed especially under stress conditions. Previously, we observed the presence of 2',3'-cAMP in Arabidopsis ( Arabidopsis thaliana ) protein complexes isolated from native lysate, suggesting that 2',3'-cAMP has potential protein partners in plants. Here, affinity purification experiments revealed that 2',3'-cAMP associates with the stress granule (SG) proteome. SGs are aggregates composed of protein and mRNA, which enable cells to selectively store mRNA for use in response to stress such as heat whereby translation initiation is impaired. Using size-exclusion chromatography and affinity purification analyses, we identified Rbp47b, the key component of SGs, as a potential interacting partner of 2',3'-cAMP. Furthermore, SG formation was promoted in 2',3'-cAMP-treated Arabidopsis seedlings, and interactions between 2',3'-cAMP and RNA-binding domains of Rbp47b, RRM2 and RRM3, were confirmed in vitro using microscale thermophoresis. Taken together, these results (1) describe novel small-molecule regulation of SG formation, (2) provide evidence for the biological role of 2',3'-cAMP, and (3) demonstrate an original biochemical pipeline for the identification of protein-metabolite interactors. © 2018 American Society of Plant Biologists. All Rights Reserved.

Binding of the cyclic AMP receptor protein of Escherichia coli to RNA polymerase.

PubMed

Pinkney, M; Hoggett, J G

1988-03-15

Fluorescence polarization studies were used to study the interaction of a fluorescein-labelled conjugate of the Escherichia coli cyclic AMP receptor protein (F-CRP) and RNA polymerase. Under conditions of physiological ionic strength, F-CRP binds to RNA polymerase holoenzyme in a cyclic AMP-dependent manner; the dissociation constant was about 3 microM in the presence of cyclic AMP and about 100 microM in its absence. Binding to core RNA polymerase under the same conditions was weak (Kdiss. approx. 80-100 microM) and independent of cyclic AMP. Competition experiments established that native CRP and F-CRP compete for the same binding site on RNA polymerase holoenzyme and that the native protein binds about 3 times more strongly than does F-CRP. Analytical ultracentrifuge studies showed that CRP binds predominantly to the monomeric rather than the dimeric form of RNA polymerase.

Microtubule-regulating proteins and cAMP-dependent signaling in neuroblastoma differentiation.

PubMed

Muñoz-Llancao, Pablo; de Gregorio, Cristian; Las Heras, Macarena; Meinohl, Christopher; Noorman, Kevin; Boddeke, Erik; Cheng, Xiaodong; Lezoualc'h, Frank; Schmidt, Martina; Gonzalez-Billault, Christian

2017-03-01

Neurons are highly differentiated cells responsible for the conduction and transmission of information in the nervous system. The proper function of a neuron relies on the compartmentalization of their intracellular domains. Differentiated neuroblastoma cells have been extensively used to study and understand the physiology and cell biology of neuronal cells. Here, we show that differentiation of N1E-115 neuroblastoma cells is more pronounced upon exposure of a chemical analog of cyclic AMP (cAMP), db-cAMP. We next analysed the expression of key microtubule-regulating proteins in differentiated cells and the expression and activation of key cAMP players such as EPAC, PKA and AKAP79/150. Most of the microtubule-promoting factors were up regulated during differentiation of N1E-115 cells, while microtubule-destabilizing proteins were down regulated. We observed an increase in tubulin post-translational modifications related to microtubule stability. As expected, db-cAMP increased PKA- and EPAC-dependent signalling. Consistently, pharmacological modulation of EPAC activity instructed cell differentiation, number of neurites, and neurite length in N1E-115 cells. Moreover, disruption of the PKA-AKAP interaction reduced these morphometric parameters. Interestingly, PKA and EPAC act synergistically to induce neuronal differentiation in N1E-115. Altogether these results show that the changes observed in the differentiation of N1E-115 cells proceed by regulating several microtubule-stabilizing factors, and the acquisition of a neuronal phenotype is a process involving concerted although independent functions of EPAC and PKA. © 2017 Wiley Periodicals, Inc.

Interplay between adenylate metabolizing enzymes and amp-activated protein kinase.

PubMed

Camici, Marcella; Allegrini, Simone; Tozzi, Maria Grazia

2018-05-18

Purine nucleotides are involved in a variety of cellular functions, such as energy storage and transfer, and signalling, in addition to being the precursors of nucleic acids and cofactors of many biochemical reactions. They can be generated through two separate pathways, the de novo biosynthesis pathway and the salvage pathway. De novo purine biosynthesis leads to the formation of IMP, from which the adenylate and guanylate pools are generated by two additional steps. The salvage pathways utilize hypoxanthine, guanine and adenine to generate the corresponding mononucleotides. Despite several decades of research on the subject, new and surprising findings on purine metabolism are constantly being reported, and some aspects still need to be elucidated. Recently, purine biosynthesis has been linked to the metabolic pathways regulated by AMP-activated protein kinase (AMPK). AMPK is the master regulator of cellular energy homeostasis, and its activity depends on the AMP:ATP ratio. The cellular energy status and AMPK activation are connected by AMP, an allosteric activator of AMPK. Hence, an indirect strategy to affect AMPK activity would be to target the pathways that generate AMP in the cell. Herein, we report an up-to-date review of the interplay between AMPK and adenylate metabolizing enzymes. Some aspects of inborn errors of purine metabolism are also discussed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

In vitro effects of diethylstilbestrol, genistein, 4-tert-butylphenol, and 4-tert-octylphenol on steroidogenic activity of isolated immature rat ovarian follicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myllymaeki, Sari; Haavisto, Tapio; Vainio, Minna

2005-04-01

Isolated rat ovarian follicles grow and produce steroid hormones in vitro and so provide a good model for studying the effects of hormonally active compounds on follicular steroidogenesis. We have evaluated the effects of diethylstilbestrol (DES), genistein (GEN) and two alkylphenols, 4-tert-butylphenol (BP) and 4-tert-octylphenol (OP) on the growth, survival, and steroid hormone and cAMP production by isolated 14-day-old rat (Sprague-Dawley) ovarian follicles. During a 5-day culture, FSH was obligatory for follicle growth and increased estradiol and testosterone secretion in a dose-dependent manner. DES (10{sup -6} M) caused the strongest decline in estradiol and testosterone levels but did not havemore » detectable effects on either cAMP production or aromatase enzyme activity. GEN caused a prominent decrease in cAMP and testosterone levels without significant changes in secreted estradiol. The latter, apparently, was due to a dose-dependent stimulation of aromatase enzyme activity in the presence of genistein. Both BP and OP decreased estradiol and testosterone secretion in a dose-dependent manner while no effect on aromatase activity was observed. OP, unlike BP, decreased forskolin-induced cAMP levels. Xenoestrogens at the used concentrations did not interfere with the growth and survival of the follicles. The results indicate that isolated ovarian follicles representing intact morphological and functional units offer a sensitive model system for elucidating the female-specific reproductive effects of environmental chemicals.« less

AKAPs: The Architectural Underpinnings of Local cAMP signaling

PubMed Central

Kritzer, Michael D.; Li, Jinliang; Dodge-Kafka, Kimberly; Kapiloff, Michael S.

2011-01-01

The cAMP-dependent protein kinase A (PKA) is targeted to specific compartments in the cardiac myocyte by A-kinase anchoring proteins (AKAPs), a diverse set of scaffold proteins that have been implicated in the regulation of excitation-contraction coupling and cardiac remodeling. AKAPs bind not only PKA, but also a large variety of structural and signaling molecules. In this review, we discuss the basic concepts underlying compartmentation of cAMP and PKA signaling, as well as a few of the individual AKAPs that have been shown to be functionally relevant in the heart. PMID:21600214

Evaluating Cumulative OP Pesticide Body Burden of Children: A National Case Study

PubMed Central

Payne-Sturges, Devon; Cohen, Jonathan; Castorina, Rosemary; Axelrad, Daniel A.; Woodruff, Tracey J.

2009-01-01

Biomonitoring is a valuable tool for identifying exposures to chemicals that pose potential harm to human health. However, to date there has been little published on ways to evaluate the relative public health significance of biomonitoring data for different chemicals, and even less on cumulative assessment of multiple chemicals. The objectives of our study are to develop a methodology for a health risk interpretation of biomonitoring data, and to apply it using NHANES 1999–2002 body burden data for organophosphorus (OP) pesticides. OP pesticides present a particularly challenging case given the non-specificity of many metabolites monitored through NHANES. We back-calculate OP pesticide exposures from urinary metabolite data, and compare cumulative dose estimates with available toxicity information for a common mechanism of action (brain cholinesterase inhibition) using data from U.S. EPA. Our results suggest that approximately 40% of children in the United States may have had insufficient margins of exposure (MOEs) for neurological impacts from cumulative exposures to OP pesticides (MOE less than 1,000). Limitations include uncertainty related to assumptions about likely precursor pesticide compounds of the urinary metabolites, sources of exposure, and intra-individual and temporal variability. PMID:19921915

The jet-ISM interactions in IC 5063

NASA Astrophysics Data System (ADS)

Mukherjee, Dipanjan; Wagner, Alexander Y.; Bicknell, Geoffrey V.; Morganti, Raffaella; Oosterloo, Tom; Nesvadba, Nicole; Sutherland, Ralph S.

2018-05-01

The interstellar medium of the radio galaxy IC 5063 is highly perturbed by an AGN jet expanding in the gaseous disc of the galaxy. We model this interaction with relativistic hydrodynamic simulations and multiphase initial conditions for the interstellar medium and compare the results with recent observations. As the jets flood through the intercloud channels of the disc, they ablate, accelerate, and disperse clouds to velocities exceeding 400 km s-1. Clouds are also destroyed or displaced in bulk from the central regions of the galaxy. Our models with jet powers of 1044 and 1045 erg s-1 are capable of reproducing many of the observed features in the position velocity diagram of IC 5063, and confirm the notion that the jet is responsible for the strongly perturbed gas dynamics seen in the ionized, neutral, and molecular gas phases. In our simulations, we also see strong venting of the jet plasma perpendicular to the disc, which entrains clumps and diffuse filaments into the halo of the galaxy. Our simulations are the first 3D hydrodynamic simulations of the jet and interstellar matter of IC 5063.

The Search for Wolf-Rayet Stars in IC10

NASA Astrophysics Data System (ADS)

Tehrani, Katie; Crowther, Paul; Archer, Isabelle

2017-11-01

We present a deep imaging and spectroscopic survey of the Local Group starburst galaxy IC10 using Gemini North/GMOS to unveil the global Wolf-Rayet population. It has previously been suggested that for IC10 to follow the WC/WN versus metallicity dependence seen in other Local Group galaxies, a large WN population must remain undiscovered. Our search revealed 3 new WN stars, and 5 candidates awaiting confirmation, providing little evidence to support this claim. We also compute an updated nebular derived metallicity of log(O/H)+12=8.40 +/- 0.04 for the galaxy using the direct method. Inspection of IC10 WR average line luminosities show these stars are more similar to their LMC, rather than SMC counterparts.

Activation of Exchange Protein Activated by Cyclic-AMP Enhances Long-Lasting Synaptic Potentiation in the Hippocampus

ERIC Educational Resources Information Center

Gelinas, Jennifer N.; Banko, Jessica L.; Peters, Melinda M.; Klann, Eric; Weeber, Edwin J.; Nguyen, Peter V.

2008-01-01

cAMP is a critical second messenger implicated in synaptic plasticity and memory in the mammalian brain. Substantial evidence links increases in intracellular cAMP to activation of cAMP-dependent protein kinase (PKA) and subsequent phosphorylation of downstream effectors (transcription factors, receptors, protein kinases) necessary for long-term…

Purification, Crystallization And Preliminary X-Ray Analysis of Aminoglycoside-2 ''-Phosphotransferase-Ic [APH(2 '')-Ic] From Enterococcus Gallinarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrnes, L.J.; /SLAC, SSRL; Badarau, A.

2009-04-30

Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity, with one such family being the aminoglycoside phosphotransferases (APHs). The gene encoding one of these enzymes, aminoglycoside-2{double_prime}-phosphotransferase-Ic [APH(2{double_prime})-Ic] from Enterococcus gallinarum, has been cloned and the wild-type protein (comprising 308 amino-acid residues) and three mutants that showed elevated minimum inhibitory concentrations towards gentamicin (F108L, H258L and a double mutant F108L/H258L) were expressed in Escherichia coli and subsequently purified. All APH(2{double_prime})-Ic variants were crystallized in the presence of 14-20%(w/v) PEG 4000, 0.25 M MgCl{sub 2}, 0.1 M Tris-HClmore » pH 8.5 and 1 mM Mg{sub 2}GTP. The crystals belong to the monoclinic space group C2, with one molecule in the asymmetric unit. The approximate unit-cell parameters are a = 82.4, b = 54.2, c = 77.0 {angstrom}, {beta} = 108.8{sup o}. X-ray diffraction data were collected to approximately 2.15 {angstrom} resolution from an F108L crystal at beamline BL9-2 at SSRL, Stanford, California, USA.« less

Eye movement instructions modulate motion illusion and body sway with Op Art

PubMed Central

Kapoula, Zoï; Lang, Alexandre; Vernet, Marine; Locher, Paul

2015-01-01

Op Art generates illusory visual motion. It has been proposed that eye movements participate in such illusion. This study examined the effect of eye movement instructions (fixation vs. free exploration) on the sensation of motion as well as the body sway of subjects viewing Op Art paintings. Twenty-eight healthy adults in orthostatic stance were successively exposed to three visual stimuli consisting of one figure representing a cross (baseline condition) and two Op Art paintings providing sense of motion in depth—Bridget Riley’s Movements in Squares and Akiyoshi Kitaoka’s Rollers. Before their exposure to the Op Art images, participants were instructed either to fixate at the center of the image (fixation condition) or to explore the artwork (free viewing condition). Posture was measured for 30 s per condition using a body fixed sensor (accelerometer). The major finding of this study is that the two Op Art paintings induced a larger antero-posterior body sway both in terms of speed and displacement and an increased motion illusion in the free viewing condition as compared to the fixation condition. For body sway, this effect was significant for the Riley painting, while for motion illusion this effect was significant for Kitaoka’s image. These results are attributed to macro-saccades presumably occurring under free viewing instructions, and most likely to the small vergence drifts during fixations following the saccades; such movements in interaction with visual properties of each image would increase either the illusory motion sensation or the antero-posterior body sway. PMID:25859197

Eye movement instructions modulate motion illusion and body sway with Op Art.

PubMed

Kapoula, Zoï; Lang, Alexandre; Vernet, Marine; Locher, Paul

2015-01-01

Op Art generates illusory visual motion. It has been proposed that eye movements participate in such illusion. This study examined the effect of eye movement instructions (fixation vs. free exploration) on the sensation of motion as well as the body sway of subjects viewing Op Art paintings. Twenty-eight healthy adults in orthostatic stance were successively exposed to three visual stimuli consisting of one figure representing a cross (baseline condition) and two Op Art paintings providing sense of motion in depth-Bridget Riley's Movements in Squares and Akiyoshi Kitaoka's Rollers. Before their exposure to the Op Art images, participants were instructed either to fixate at the center of the image (fixation condition) or to explore the artwork (free viewing condition). Posture was measured for 30 s per condition using a body fixed sensor (accelerometer). The major finding of this study is that the two Op Art paintings induced a larger antero-posterior body sway both in terms of speed and displacement and an increased motion illusion in the free viewing condition as compared to the fixation condition. For body sway, this effect was significant for the Riley painting, while for motion illusion this effect was significant for Kitaoka's image. These results are attributed to macro-saccades presumably occurring under free viewing instructions, and most likely to the small vergence drifts during fixations following the saccades; such movements in interaction with visual properties of each image would increase either the illusory motion sensation or the antero-posterior body sway.

Structural basis for the mutual antagonism of cAMP and TRIP8b in regulating HCN channel function

PubMed Central

Saponaro, Andrea; Pauleta, Sofia R.; Cantini, Francesca; Matzapetakis, Manolis; Hammann, Christian; Donadoni, Chiara; Hu, Lei; Thiel, Gerhard; Banci, Lucia; Santoro, Bina; Moroni, Anna

2014-01-01

cAMP signaling in the brain mediates several higher order neural processes. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels directly bind cAMP through their cytoplasmic cyclic nucleotide binding domain (CNBD), thus playing a unique role in brain function. Neuronal HCN channels are also regulated by tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b), an auxiliary subunit that antagonizes the effects of cAMP by interacting with the channel CNBD. To unravel the molecular mechanisms underlying the dual regulation of HCN channel activity by cAMP/TRIP8b, we determined the NMR solution structure of the HCN2 channel CNBD in the cAMP-free form and mapped on it the TRIP8b interaction site. We reconstruct here the full conformational changes induced by cAMP binding to the HCN channel CNBD. Our results show that TRIP8b does not compete with cAMP for the same binding region; rather, it exerts its inhibitory action through an allosteric mechanism, preventing the cAMP-induced conformational changes in the HCN channel CNBD. PMID:25197093

Controlling fertilization and cAMP signaling in sperm by optogenetics.

PubMed

Jansen, Vera; Alvarez, Luis; Balbach, Melanie; Strünker, Timo; Hegemann, Peter; Kaupp, U Benjamin; Wachten, Dagmar

2015-01-20

Optogenetics is a powerful technique to control cellular activity by light. The light-gated Channelrhodopsin has been widely used to study and manipulate neuronal activity in vivo, whereas optogenetic control of second messengers in vivo has not been examined in depth. In this study, we present a transgenic mouse model expressing a photoactivated adenylyl cyclase (bPAC) in sperm. In transgenic sperm, bPAC mimics the action of the endogenous soluble adenylyl cyclase (SACY) that is required for motility and fertilization: light-stimulation rapidly elevates cAMP, accelerates the flagellar beat, and, thereby, changes swimming behavior of sperm. Furthermore, bPAC replaces endogenous adenylyl cyclase activity. In mutant sperm lacking the bicarbonate-stimulated SACY activity, bPAC restored motility after light-stimulation and, thereby, enabled sperm to fertilize oocytes in vitro. We show that optogenetic control of cAMP in vivo allows to non-invasively study cAMP signaling, to control behaviors of single cells, and to restore a fundamental biological process such as fertilization.

The Vida Verde Women's Co-Op: Brazilian immigrants organizing to promote environmental and social justice.

PubMed

Gute, David M; Siqueira, Eduardo; Goldberg, Julia S; Galvão, Heloisa; Chianelli, Mônica; Pirie, Alex

2009-11-01

We reviewed the key steps in the launch of the Vida Verde Women's Co-Op among Brazilian immigrant housecleaners in Somerville, MA. The co-op provides green housecleaning products, encourages healthy work practices, and promotes a sense of community among its members. We conducted in-depth interviews with 8 of the first co-op members, who reported a reduction in symptoms associated with the use of traditional cleaning agents and a new sense of mutual support. Critical to the co-op's success have been the supportive roles of its academic partners (Tufts University and the University of Massachusetts, Lowell), effective media outreach, and a focus on advancing social justice. Next steps include implementing a formal business plan and assessing the appropriateness of cooperatives in other industries.

48 CFR 750.7110-3 - Submission of cases to the M/OP Director.

Code of Federal Regulations, 2011 CFR

2011-10-01

... M/OP Director. 750.7110-3 Section 750.7110-3 Federal Acquisition Regulations System AGENCY FOR... Actions To Protect Foreign Policy Interests of the United States 750.7110-3 Submission of cases to the M/OP Director. Cases to be submitted for consideration by the M/OAA Director shall be prepared and...

Opposing actions of dibutyryl cyclic AMP and GMP on temperature in conscious guinea-pigs

NASA Technical Reports Server (NTRS)

Kandasamy, S. B.; Williaes, B. A.

1983-01-01

It is shown that the intracerebroventricular administration of dibutyryl cyclic AMP (Db-cAMP) induced hyperthermia in guinea pigs which was not mediated through prostaglandins or norepinephrine since a prostaglandin synthesis inhibitor and an alpha-adrenergic receptor blocking agent did not antagonize the hyperthermia. However, the hyperthermic response to Db-cAMP was attenuated by the central administration of a beta-adrenergic receptor antagonist, which indicates that cAMP may be involved, through beta-adrenergic receptors, in the central regulation of heat production and conservation. The central administration of Db-cGMP produced hypothermia which was not mediated via histamine H1 or H2 receptors and serotonin. The antagonism of hypothermia induced by Db-cGMP and acetylcholine + physostigmine by central administration of a cholinergic muscarine receptor antagonist and not by a cholinergic nicotinic receptor antagonist suggests that cholinoceptive neurons and endogenous cGMP may regulate heat loss through cholinergic muscarine receptors. It is concluded that these results indicate a regulatory role in thermoregulation provided by a balance between opposing actions of cAMP and cGMP in guinea pigs.

Binding of the cyclic AMP receptor protein of Escherichia coli to RNA polymerase.

PubMed Central

Pinkney, M; Hoggett, J G

1988-01-01

Fluorescence polarization studies were used to study the interaction of a fluorescein-labelled conjugate of the Escherichia coli cyclic AMP receptor protein (F-CRP) and RNA polymerase. Under conditions of physiological ionic strength, F-CRP binds to RNA polymerase holoenzyme in a cyclic AMP-dependent manner; the dissociation constant was about 3 microM in the presence of cyclic AMP and about 100 microM in its absence. Binding to core RNA polymerase under the same conditions was weak (Kdiss. approx. 80-100 microM) and independent of cyclic AMP. Competition experiments established that native CRP and F-CRP compete for the same binding site on RNA polymerase holoenzyme and that the native protein binds about 3 times more strongly than does F-CRP. Analytical ultracentrifuge studies showed that CRP binds predominantly to the monomeric rather than the dimeric form of RNA polymerase. PMID:2839152

Elevated Cyclic AMP Levels in T Lymphocytes Transformed by Human T-Cell Lymphotropic Virus Type 1▿

PubMed Central

Kress, Andrea K.; Schneider, Grit; Pichler, Klemens; Kalmer, Martina; Fleckenstein, Bernhard; Grassmann, Ralph

2010-01-01

Human T-cell lymphotropic virus type 1 (HTLV-1), the cause of adult T-cell leukemia/lymphoma (ATLL), transforms CD4+ T cells to permanent growth through its transactivator Tax. HTLV-1-transformed cells share phenotypic properties with memory and regulatory T cells (T-reg). Murine T-reg-mediated suppression employs elevated cyclic AMP (cAMP) levels as a key regulator. This led us to determine cAMP levels in HTLV-1-transformed cells. We found elevated cAMP concentrations as a consistent feature of all HTLV-1-transformed cell lines, including in vitro-HTLV-1-transformed, Tax-transformed, and patient-derived cells. In transformed cells with conditional Tax expression, high cAMP levels coincided with the presence of Tax but were lost without it. However, transient ectopic expression of Tax alone was not sufficient to induce cAMP. We found specific downregulation of the cAMP-degrading phosphodiesterase 3B (PDE3B) in HTLV-1-transformed cells, which was independent of Tax in transient expression experiments. This is in line with the notion that PDE3B transcripts and cAMP levels are inversely correlated. Overexpression of PDE3B led to a decrease of cAMP in HTLV-1-transformed cells. Decreased expression of PDE3B was associated with inhibitory histone modifications at the PDE3B promoter and the PDE3B locus. In summary, Tax transformation and its continuous expression contribute to elevated cAMP levels, which may be regulated through PDE3B suppression. This shows that HTLV-1-transformed cells assume biological features of long-lived T-cell populations that potentially contribute to viral persistence. PMID:20573814

Extended-spectrum β-lactamase/AmpC- and carbapenemase-producing Enterobacteriaceae in animals: a threat for humans?

PubMed

Madec, J-Y; Haenni, M; Nordmann, P; Poirel, L

2017-11-01

There has been a great and long-term concern that extended-spectrum β-lactamase (ESBL)/AmpC- and carbapenemase-producing Enterobacteriaceae occurring in animals may constitute a public-health issue. A large number of factors with complex interrelations contribute to the spread of those bacteria among animals and humans. ESBL/AmpC- or carbapenemase-encoding genes are most often located on mobile genetic elements favouring their dissemination. Some shared reservoirs of ESBL/AmpC or carbapenemase genes, plasmids or clones have been identified and suggest cross-transmissions. Even though exposure to animals is regarded as a risk factor, evidence for a direct transfer of ESBL/AmpC-producing bacteria from animals to humans through close contacts is limited. Nonetheless, the size of the commensal ESBL/AmpC reservoir in non-human sources is dramatically rising. This may constitute an indirect risk to public health by increasing the gene pool from which pathogenic bacteria can pick up ESBL/AmpC/carbapenemase genes. The extent to which food contributes to potential transmission of ESBL/AmpC producers to humans is also not well established. Overall, events leading to the occurrence of ESBL/AmpC- and carbapenemase-encoding genes in animals seem very much multifactorial. The impact of animal reservoirs on human health still remains debatable and unclear; nonetheless, there are some examples of direct links that have been identified. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Regulation of theta-antigen expression by agents altering cyclic AMP level and by thymic factor.

PubMed

Bach, M A; Fournier, C; Bach, J F

1975-02-28

Thymic factor, cyclic AMP, and products increasing its cellular level, such as Prostaglandin E1, induce the appearance of the theta-antigen on T-cell precursors whether assessed by a rossette-inhibition assay or a cytotoxic assay after cell fractionation on BSA discontinuous gradiet. Synergism has been demonstrated between cyclic AMPT and TF for that effect. Conversely, decrease of theta expression has been obtained by altering cyclic AMP level in theta-positive cells either increasing it by dibutyryl cAMP treatment or decreasing it by indomethacin treatment. Finally, these data suggest the involvement of cyclic AMP in the regulation of theta expression under thymic hormone control.

Analog bus driver and multiplexer

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Hancock, Bruce (Inventor); Cunningham, Thomas J. (Inventor)

2012-01-01

For a source-follower signal chain, the ohmic drop in the selection switch causes unacceptable voltage offset, non-linearity, and reduced small signal gain. For an op amp signal chain, the required bias current and the output noise rises rapidly with increasing the array format due to a rapid increase in the effective capacitance caused by the Miller effect boosting up the contribution of the bus capacitance. A new switched source-follower signal chain circuit overcomes limitations of existing op-amp based or source follower based circuits used in column multiplexers and data readout. This will improve performance of CMOS imagers, and focal plane read-out integrated circuits for detectors of infrared or ultraviolet light.

Decoding spatial and temporal features of neuronal cAMP/PKA signaling with FRET biosensors.

PubMed

Castro, Liliana R V; Guiot, Elvire; Polito, Marina; Paupardin-Tritsch, Daniéle; Vincent, Pierre

2014-02-01

Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP-dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, pathfinding, efficacy of synaptic transmission, regulation of excitability, or long term changes. Genetically encoded optical biosensors for cAMP or PKA are considerably improving our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progress made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the sub-cellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus, and axon. Combining this imaging approach with pharmacology or genetic models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly emerge as a forefront tool to decipher the subtle mechanics of intracellular signaling. This will certainly help us to understand the mechanism of action of current drugs and foster the development of novel molecules for neuropsychiatric diseases. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Odor-Specific Threshold Deficit Implicates Abnormal Intracellular Cyclic AMP Signaling in Schizophrenia

PubMed Central

Turetsky, Bruce I.; Moberg, Paul J.

2012-01-01

Objective Although olfactory deficits are common in schizophrenia, their underlying pathophysiology remains unknown. Recent evidence has suggested that cAMP signaling may be disrupted in schizophrenia. Since cAMP mediates signal transduction in olfactory receptor neurons, this could contribute to the etiology of observed olfactory deficits. This study was designed to test this hypothesis by determining odor detection threshold sensitivities to two odorants that differ in their relative activations of this intracellular cAMP signaling cascade. Method Thirty schizophrenia patients, 25 healthy comparison subjects, and 19 unaffected first-degree relatives of schizophrenia patients were studied. Odor detection threshold sensitivities were measured for the two odorants citralva and lyral. Although both have fruity/floral scents, citralva strongly activates adenylyl cyclase to increase cAMP levels, while lyral is a very weak activator of adenylyl cyclase. Results There was a significant group-by-odor interaction. Both schizophrenia patients and unaffected first-degree relatives were impaired in their ability to detect lyral versus citralva. Comparison subjects were equally sensitive to both odorants. This selective deficit could not be explained by differences in age, sex, smoking, clinical symptom profile, or medication use. Conclusions This study establishes the presence of an odor-specific hyposmia that may denote a disruption of cAMP-mediated signal transduction in schizophrenia. The presence of a parallel deficit in the patients’ unaffected first-degree relatives suggests that this deficit is genetically mediated. Although additional physiological studies are needed to confirm the underlying mechanism, these results offer strong inferential support for the hypothesis that cAMP signaling is dys-regulated in schizophrenia. PMID:19074977

An odor-specific threshold deficit implicates abnormal intracellular cyclic AMP signaling in schizophrenia.

PubMed

Turetsky, Bruce I; Moberg, Paul J

2009-02-01

Although olfactory deficits are common in schizophrenia, their underlying pathophysiology remains unknown. Recent evidence has suggested that cAMP signaling may be disrupted in schizophrenia. Since cAMP mediates signal transduction in olfactory receptor neurons, this could contribute to the etiology of observed olfactory deficits. This study was designed to test this hypothesis by determining odor detection threshold sensitivities to two odorants that differ in their relative activations of this intracellular cAMP signaling cascade. Thirty schizophrenia patients, 25 healthy comparison subjects, and 19 unaffected first-degree relatives of schizophrenia patients were studied. Odor detection threshold sensitivities were measured for the two odorants citralva and lyral. Although both have fruity/floral scents, citralva strongly activates adenylyl cyclase to increase cAMP levels, while lyral is a very weak activator of adenylyl cyclase. There was a significant group-by-odor interaction. Both schizophrenia patients and unaffected first-degree relatives were impaired in their ability to detect lyral versus citralva. Comparison subjects were equally sensitive to both odorants. This selective deficit could not be explained by differences in age, sex, smoking, clinical symptom profile, or medication use. This study establishes the presence of an odor-specific hyposmia that may denote a disruption of cAMP-mediated signal transduction in schizophrenia. The presence of a parallel deficit in the patients' unaffected first-degree relatives suggests that this deficit is genetically mediated. Although additional physiological studies are needed to confirm the underlying mechanism, these results offer strong inferential support for the hypothesis that cAMP signaling is dysregulated in schizophrenia.

75 FR 54940 - Agency Information Collection (IC) Activities; Revision of an Approved IC; Accident Recordkeeping...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

... include the Agency name and the docket number for this Notice. Note that DOT posts all comments received... underlying this IC is 49 CFR 390.15, ``Assistance in investigations and special studies.'' It requires motor... Information Technology. [FR Doc. 2010-22456 Filed 9-8-10; 8:45 am] BILLING CODE 4910-EX-P ...

cAMP inhibits inducible nitric oxide synthase expression and NF-kappaB-binding activity in cultured rat hepatocytes.

PubMed

Harbrecht, B G; Taylor, B S; Xu, Z; Ramalakshmi, S; Ganster, R W; Geller, D A

2001-08-01

The inducible nitric oxide synthase (iNOS) is strongly expressed following inflammatory stimuli. Adenosine 3',5'-cyclic monophosphate (cAMP) increases iNOS expression and activity in a number of cell types but decreases cytokine-stimulated iNOS expression in hepatocytes. The mechanisms for this effect are unknown. Rat hepatocytes were stimulated with cytokines to induce iNOS and cultured with cAMP agonists dibutyryl-cAMP (dbcAMP), 8-bromo-cAMP, and forskolin (FSK). Nitric oxide synthesis was assessed by supernatant nitrite levels and iNOS expression was measured by Northern and Western blot analyses. Nuclear factor kappaB binding was assessed by electromobility shift assay. Cyclic AMP dose dependently decreased NO synthesis in response to a combination of proinflammatory cytokines or interleukin-1beta (IL-1beta) alone. The adenylate cyclase inhibitor SQ 22,536 increased cytokine- or IL-1beta-stimulated NO synthesis. dbcAMP decreased iNOS mRNA expression and iNOS protein expression. Both dbcAMP and glucagon decreased iNOS promoter activity in rat hepatocytes transfected with the murine iNOS promoter and decreased DNA binding of the transcription factor NF-kappaB. These data suggest that cAMP is important in hepatocyte iNOS expression and agents that alter cAMP levels may profoundly alter the response of hepatocytes to inflammatory stimuli through effects onthe iNOS promoter region and NF-kappaB. Copyright 2001 Academic Press.

Molecular basis for the recognition of cyclic-di-AMP by PstA, a PII-like signal transduction protein.

PubMed

Choi, Philip H; Sureka, Kamakshi; Woodward, Joshua J; Tong, Liang

2015-06-01

Cyclic-di-AMP (c-di-AMP) is a broadly conserved bacterial second messenger that is of importance in bacterial physiology. The molecular receptors mediating the cellular responses to the c-di-AMP signal are just beginning to be discovered. PstA is a previously uncharacterized PII -like protein which has been identified as a c-di-AMP receptor. PstA is widely distributed and conserved among Gram-positive bacteria in the phylum Firmicutes. Here, we report the biochemical, structural, and functional characterization of PstA from Listeria monocytogenes. We have determined the crystal structures of PstA in the c-di-AMP-bound and apo forms at 1.6 and 2.9 Å resolution, respectively, which provide the molecular basis for its specific recognition of c-di-AMP. PstA forms a homotrimer structure that has overall similarity to the PII protein family which binds ATP. However, PstA is markedly different from PII proteins in the loop regions, and these structural differences mediate the specific recognition of their respective nucleotide ligand. The residues composing the c-di-AMP binding pocket are conserved, suggesting that c-di-AMP recognition by PstA is of functional importance. Disruption of pstA in L. monocytogenes affected c-di-AMP-mediated alterations in bacterial growth and lysis. Overall, we have defined the PstA family as a conserved and specific c-di-AMP receptor in bacteria. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

75 FR 16874 - Market Test of “Samples Co-Op Box” Experimental Product

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

... POSTAL SERVICE Market Test of ``Samples Co-Op Box'' Experimental Product AGENCY: Postal Service TM . ACTION: Notice. SUMMARY: The Postal Service gives notice of a market test of an experimental product in... pursuant to 39 U.S.C. 3641(c)(1) that it will begin a market test of its ``Samples Co-Op Box'' experimental...

A Temporal-Specific and Transient cAMP Increase Characterizes Odorant Classical Conditioning

ERIC Educational Resources Information Center

Cui, Wen; Smith, Andrew; Darby-King, Andrea; Harley, Carolyn W.; McLean, John H.

2007-01-01

Increases in cyclic adenosine monophosphate (cAMP) are proposed to initiate learning in a wide variety of species. Here, we measure changes in cAMP in the olfactory bulb prior to, during, and following a classically conditioned odor preference trial in rat pups. Measurements were taken up to the point of maximal CREB phosphorylation in olfactory…

Genotypic and Phenotypic Detection of AmpC β-lactamases in Enterobacter spp. Isolated from a Teaching Hospital in Malaysia.

PubMed

Mohd Khari, Fatin Izzati; Karunakaran, Rina; Rosli, Roshalina; Tee Tay, Sun

2016-01-01

The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012-February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test. Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and AmpC induction tests, respectively

Genotypic and Phenotypic Detection of AmpC β-lactamases in Enterobacter spp. Isolated from a Teaching Hospital in Malaysia

PubMed Central

Mohd Khari, Fatin Izzati; Karunakaran, Rina; Rosli, Roshalina; Tee Tay, Sun

2016-01-01

Objectives The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. Methods Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012—February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test. Results Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and Amp

An integrable family of Monge-Ampère equations and their multi-Hamiltonian structure

NASA Astrophysics Data System (ADS)

Nutku, Y.; Sarioǧlu, Ö.

1993-02-01

We have identified a completely integrable family of Monge-Ampère equations through an examination of their Hamiltonian structure. Starting with a variational formulation of the Monge-Ampère equations we have constructed the first Hamiltonian operator through an application of Dirac's theory of constraints. The completely integrable class of Monge-Ampère equations are then obtained by solving the Jacobi identities for a sufficiently general form of the second Hamiltonian operator that is compatible with the first.

ICECAP: an integrated, general-purpose, automation-assisted IC50/EC50 assay platform.

PubMed

Li, Ming; Chou, Judy; King, Kristopher W; Jing, Jing; Wei, Dong; Yang, Liyu

2015-02-01

IC50 and EC50 values are commonly used to evaluate drug potency. Mass spectrometry (MS)-centric bioanalytical and biomarker labs are now conducting IC50/EC50 assays, which, if done manually, are tedious and error-prone. Existing bioanalytical sample preparation automation systems cannot meet IC50/EC50 assay throughput demand. A general-purpose, automation-assisted IC50/EC50 assay platform was developed to automate the calculations of spiking solutions and the matrix solutions preparation scheme, the actual spiking and matrix solutions preparations, as well as the flexible sample extraction procedures after incubation. In addition, the platform also automates the data extraction, nonlinear regression curve fitting, computation of IC50/EC50 values, graphing, and reporting. The automation-assisted IC50/EC50 assay platform can process the whole class of assays of varying assay conditions. In each run, the system can handle up to 32 compounds and up to 10 concentration levels per compound, and it greatly improves IC50/EC50 assay experimental productivity and data processing efficiency. © 2014 Society for Laboratory Automation and Screening.

Wide-Field Structure of Local Group Dwarf Irregular Galaxy IC1613

NASA Astrophysics Data System (ADS)

Pucha, Ragadeepika; Carlin, Jeffrey; Willman, Beth; Sand, David J.; Bechtol, Keith

2018-01-01

IC1613 is a typical dwarf irregular galaxy in the Local Group. Being an isolated dwarf, as opposed to the dwarfs around the Milky Way, it is likely to be subjected to fewer strong environmental effects. As a result, it serves as a good prototype for the study of the structure and evolution of dwarf galaxies. We present g- and i- band photometry from deep imaging of four fields around IC1613, that resolved stars up to ~ 4 magnitudes fainter than the tip of the RGB. This photometry was obtained using Hyper-Suprime Cam (HSC) on the Subaru Telescope. The large (1.5o) field-of-view of HSC provides us with a unique opportunity to study the wide-field structure of this dwarf galaxy. This project explores the structure of IC1613 to radii of about ~ 25 kpc using different types of stellar tracers. The aim is to search for evidence of a stellar halo or stellar over-densities around IC1613. The relative contributions of the different stellar populations as a function of position in IC1613 are also shown.

Recombinant human osteogenic protein-1 (OP-1) stimulates periodontal wound healing in class III furcation defects.

PubMed

Giannobile, W V; Ryan, S; Shih, M S; Su, D L; Kaplan, P L; Chan, T C

1998-02-01

Osteogenic protein-1 (OP-1) is a member of the transforming growth factor beta superfamily and is a potent modulator of osteogenesis and bone cell differentiation. This preclinical study in dogs sought to assess the effects of OP-1 on periodontal wound healing in surgically created critical size Class III furcation defects. Eighteen male beagle dogs were subjected to the creation of bilateral mandibular 5 mm osseous defects. A split-mouth design was utilized which randomly assigned opposing quadrants to control therapy (surgery alone or collagen vehicle) or 1 of 3 ascending concentrations of OP-1 in a collagen vehicle (0.75 mg OP-1/g collagen, 2.5 mg/g, or 7.5 mg/g). Thus, 9 quadrants per test group received OP-1, 9 quadrants per control group received surgery alone, and 9 quadrants received collagen vehicle alone. Test articles were delivered by a surgeon masked to the treatment, and fluorogenic bone labels were injected at specified intervals post-treatment. Eight weeks after defect creation and OP-1 delivery, tissue blocks of the mandibulae were taken for masked histomorphometric analysis to assess parameters of periodontal regeneration (e.g., bone height, bone area, new attachment formation, and percent of defect filled with new bone). Histomorphometry revealed limited evidence of osteogenesis, cementogenesis, and new attachment formation in either vehicle or surgery-alone sites. In contrast, sites treated with all 3 concentrations of OP-1 showed pronounced stimulation of osteogenesis, regenerative cementum, and new attachment formation. Lesions treated with 7.5 mg/g of OP-1 in collagen regenerated 3.9+/-1.7 mm and 6.1+/-3.4 mm2 (mean +/-S.D.) of linear bone height and bone area, respectively. Furthermore, these differences were statistically different from both control therapies for all wound healing parameters (P < 0.0001). No significant increase in tooth root ankylosis was found among the treatment groups when compared to the surgery-alone group. We

Plasmids encoding PKI(1-31), a specific inhibitor of cAMP-stimulated gene expression, inhibit the basal transcriptional activity of some but not all cAMP-regulated DNA response elements in JEG-3 cells.

PubMed

Grove, J R; Deutsch, P J; Price, D J; Habener, J F; Avruch, J

1989-11-25

Plasmids that encode a bioactive amino-terminal fragment of the heat-stable inhibitor of the cAMP-dependent protein kinase, PKI(1-31), were employed to characterize the role of this protein kinase in the control of transcriptional activity mediated by three DNA regulatory elements in the JEG-3 human placental cell line. The 5'-flanking sequence of the human collagenase gene contains the heptameric sequence, 5'-TGAGTCA-3', previously identified as a "phorbol ester" response element. Reporter genes containing either the intact 1.2-kilobase 5'-flanking sequence from the human collagenase gene or just the 7-base pair (bp) response element, when coupled to an enhancerless promoter, each exhibit both cAMP and phorbol ester-stimulated expression in JEG-3 cells. Cotransfection of either construct with plasmids encoding PKI(1-31) inhibits cAMP-stimulated but not basal- or phorbol ester-stimulated expression. Pretreatment of cells with phorbol ester for 1 or 2 days abrogates completely the response to rechallenge with phorbol ester but does not alter the basal expression of either construct; cAMP-stimulated expression, while modestly inhibited, remains vigorous. The 5'-flanking sequence of the human chorionic gonadotropin-alpha subunit (HCG alpha) gene has two copies of the sequence, 5'-TGACGTCA-3', contained in directly adjacent identical 18-bp segments, previously identified as a cAMP-response element. Reporter genes containing either the intact 1.5 kilobase of 5'-flanking sequence from the HCG alpha gene, or just the 36-bp tandem repeat cAMP response element, when coupled to an enhancerless promoter, both exhibit a vigorous cAMP stimulation of expression but no response to phorbol ester in JEG-3 cells. Cotransfection with plasmids encoding PKI(1-31) inhibits both basal and cAMP-stimulated expression in a parallel fashion. The 5'-flanking sequence of the human enkephalin gene mediates cAMP-stimulated expression of reporter genes in both JEG-3 and CV-1 cells. Plasmids

Keeping the home fires burning†: AMP-activated protein kinase

PubMed Central

2018-01-01

Living cells obtain energy either by oxidizing reduced compounds of organic or mineral origin or by absorbing light. Whichever energy source is used, some of the energy released is conserved by converting adenosine diphosphate (ADP) to adenosine triphosphate (ATP), which are analogous to the chemicals in a rechargeable battery. The energy released by the conversion of ATP back to ADP is used to drive most energy-requiring processes, including cell growth, cell division, communication and movement. It is clearly essential to life that the production and consumption of ATP are always maintained in balance, and the AMP-activated protein kinase (AMPK) is one of the key cellular regulatory systems that ensures this. In eukaryotic cells (cells with nuclei and other internal membrane-bound structures, including human cells), most ATP is produced in mitochondria, which are thought to have been derived by the engulfment of oxidative bacteria by a host cell not previously able to use molecular oxygen. AMPK is activated by increasing AMP or ADP (AMP being generated from ADP whenever ADP rises) coupled with falling ATP. Relatives of AMPK are found in essentially all eukaryotes, and it may have evolved to allow the host cell to monitor the output of the newly acquired mitochondria and step their ATP production up or down according to the demand. Structural studies have illuminated how AMPK achieves the task of detecting small changes in AMP and ADP, despite the presence of much higher concentrations of ATP. Recently, it has been shown that AMPK can also sense the availability of glucose, the primary carbon source for most eukaryotic cells, via a mechanism independent of changes in AMP or ADP. Once activated by energy imbalance or glucose lack, AMPK modifies many target proteins by transferring phosphate groups to them from ATP. By this means, numerous ATP-producing processes are switched on (including the production of new mitochondria) and ATP-consuming processes are switched

Forskolin-free cAMP assay for Gi-coupled receptors.

PubMed

Gilissen, Julie; Geubelle, Pierre; Dupuis, Nadine; Laschet, Céline; Pirotte, Bernard; Hanson, Julien

2015-12-01

G protein-coupled receptors (GPCRs) represent the most successful receptor family for treating human diseases. Many are poorly characterized with few ligands reported or remain completely orphans. Therefore, there is a growing need for screening-compatible and sensitive assays. Measurement of intracellular cyclic AMP (cAMP) levels is a validated strategy for measuring GPCRs activation. However, agonist ligands for Gi-coupled receptors are difficult to track because inducers such as forskolin (FSK) must be used and are sources of variations and errors. We developed a method based on the GloSensor system, a kinetic assay that consists in a luciferase fused with cAMP binding domain. As a proof of concept, we selected the succinate receptor 1 (SUCNR1 or GPR91) which could be an attractive drug target. It has never been validated as such because very few ligands have been described. Following analyses of SUCNR1 signaling pathways, we show that the GloSensor system allows real time, FSK-free detection of an agonist effect. This FSK-free agonist signal was confirmed on other Gi-coupled receptors such as CXCR4. In a test screening on SUCNR1, we compared the results obtained with a FSK vs FSK-free protocol and were able to identify agonists with both methods but with fewer false positives when measuring the basal levels. In this report, we validate a cAMP-inducer free method for the detection of Gi-coupled receptors agonists compatible with high-throughput screening. This method will facilitate the study and screening of Gi-coupled receptors for active ligands. Copyright © 2015 Elsevier Inc. All rights reserved.

30 CFR 57.22203 - Main fan operation (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main fan operation (I-C mines). 57.22203... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22203 Main fan operation (I-C mines). Main fans shall be operated continuously while ore production is in progress. ...

Simultaneous detection of three lily viruses using Triplex IC-RT-PCR.

PubMed

Zhang, Yubao; Wang, Yajun; Xie, Zhongkui; Yang, Guo; Guo, Zhihong; Wang, Le

2017-11-01

Viruses commonly infecting lily (Lilium spp.) include: Lily symptomless virus (LSV), Cucumber mosaic virus (CMV) and Lily mottle virus (LMoV). These viruses usually co-infect lilies causing severe economic losses in terms of quantity and quality of flower and bulb production around the world. Reliable and precise detection systems need to be developed for virus identification. We describe the development of a triplex immunocapture (IC) reverse transcription (RT) polymerase chain reaction (PCR) assay for the simultaneous detection of LSV, CMV and LMoV. The triplex IC-RT-PCR was compared with a quadruplex RT-PCR assay. Relative to the quadruplex RT-PCR, the specificity of the triplex IC-RT-PCR system for LSV, CMV and LMoV was 100% for field samples. The sensitivity of the triplex IC-RT-PCR system was 99.4%, 81.4% and 98.7% for LSV, CMV and LMoV, respectively. Agreement (κ) between the results obtained from the two tests was 0.968, 0.844 and 0.984 for LSV, CMV and LMoV, respectively. This is the first report of the simultaneous detection of LSV, CMV and LMoV in a triplex IC-RT-PCR assay. In particular we believe this convenient and reliable triplex IC-RT-PCR method could be used routinely for large-scale field surveys or crop health monitoring of lily. Copyright © 2017. Published by Elsevier B.V.

cAMP signalling in mushroom bodies modulates temperature preference behaviour in Drosophila.

PubMed

Hong, Sung-Tae; Bang, Sunhoe; Hyun, Seogang; Kang, Jongkyun; Jeong, Kyunghwa; Paik, Donggi; Chung, Jongkyeong; Kim, Jaeseob

2008-08-07

Homoiotherms, for example mammals, regulate their body temperature with physiological responses such as a change of metabolic rate and sweating. In contrast, the body temperature of poikilotherms, for example Drosophila, is the result of heat exchange with the surrounding environment as a result of the large ratio of surface area to volume of their bodies. Accordingly, these animals must instinctively move to places with an environmental temperature as close as possible to their genetically determined desired temperature. The temperature that Drosophila instinctively prefers has a function equivalent to the 'set point' temperature in mammals. Although various temperature-gated TRP channels have been discovered, molecular and cellular components in Drosophila brain responsible for determining the desired temperature remain unknown. We identified these components by performing a large-scale genetic screen of temperature preference behaviour (TPB) in Drosophila. In parallel, we mapped areas of the Drosophila brain controlling TPB by targeted inactivation of neurons with tetanus toxin and a potassium channel (Kir2.1) driven with various brain-specific GAL4s. Here we show that mushroom bodies (MBs) and the cyclic AMP-cAMP-dependent protein kinase A (cAMP-PKA) pathway are essential for controlling TPB. Furthermore, targeted expression of cAMP-PKA pathway components in only the MB was sufficient to rescue abnormal TPB of the corresponding mutants. Preferred temperatures were affected by the level of cAMP and PKA activity in the MBs in various PKA pathway mutants.

Renal Epithelial Cyst Formation and Enlargement in vitro: Dependence on cAMP

NASA Astrophysics Data System (ADS)

Mangoo-Karim, Roberto; Uchic, Marie; Lechene, Claude; Grantham, Jared J.

1989-08-01

Cysts, a common abnormality of kidneys, are collections of urine-like fluid enclosed by a continuous layer of epithelial cells. Renal cysts derive from nephrons and collecting ducts and progressively enlarge as a consequence of epithelial proliferation and transepithelial fluid secretion. The initiation of cyst formation and the factors that control cyst enlargement are unknown. We used an in vitro model of renal cysts to explore the role of the cAMP signal transduction system in the formation and expansion of cysts. MDCK cells, cultured in hydrated-collagen gel, produced polarized monolayered epithelial cysts when intracellular cAMP was increased by prostaglandin E1, arginine vasopressin, cholera toxin, forskolin, or 8-bromoadenosine 3',5'-cyclic monophosphate. All agonists were potentiated by 3-isobutyl-1-methylxanthine, a nucleotide phosphodiesterase inhibitor. The cell proliferation component of cyst enlargement was accelerated by cAMP agonists, as shown by the increased growth of MDCK cells in subconfluent monolayers. The fluid secretion component, reflected by the transepithelial movement of fluid across polarized monolayers of MDCK cells grown on permeable supports, was stimulated by cAMP agonists in the basolateral medium. Chloride levels were higher in the cyst fluid and the secreted fluid than in the bathing medium. We conclude that the development of MDCK cysts is dependent on cAMP. This signal transduction system may be an important modulator of epithelial cell proliferation and transepithelial fluid secretion in the kidney.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myllymaeki, S.A.; Karjalainen, M.; Haavisto, T.E.

Phenolic compounds, such as 4-tert-octylphenol (OP), have been shown to interfere with rat ovarian steroidogenesis. However, little is known about steroidogenic effects of infantile OP exposure on immature ovary. The aim of the present study was to investigate the effects of infantile OP exposure on plasma FSH, LH, estradiol, and progesterone levels in 14-day-old female rats. The effect on ovarian steroidogenic acute regulatory protein (StAR) and FSH receptor (FSHr) expression was analyzed by Western blotting. Ex vivo analysis was carried out for follicular estradiol, progesterone, testosterone, and cAMP production. Sprague-Dawley rats were given OP (0, 10, 50, or 100 mg/kg)more » subcutaneously on postnatal days 6, 8, 10, and 12. On postnatal day 14, plasma FSH was decreased and progesterone increased significantly at a dose of 100 mg OP/kg. In addition, the highest OP dose advanced the time of vaginal opening in puberty. OP had no effect on infantile LH and estradiol levels or ovarian FSHr content. Ovarian StAR protein content and ex vivo hormone and cAMP production were decreased at all OP doses compared to controls. However, hormone levels recovered independent on FSH and even increased above the control level during a prolonged culture. On postnatal day 35, no statistically significant differences were seen between control and OP-exposed animals in plasma FSH, LH, estradiol, and progesterone levels, or in ovarian StAR protein content. The results indicate that the effect of OP on the infantile ovary is reversible, while more permanent effects in the hypothalamus and pituitary, as described earlier, are involved in the reduction of circulating FSH levels and premature vaginal opening.« less

cAMP-secretion coupling is impaired in diabetic GK/Par rat β-cells: a defect counteracted by GLP-1.

PubMed

Dolz, Manuel; Movassat, Jamileh; Bailbé, Danielle; Le Stunff, Hervé; Giroix, Marie-Hélène; Fradet, Magali; Kergoat, Micheline; Portha, Bernard

2011-11-01

cAMP-raising agents with glucagon-like peptide-1 (GLP-1) as the first in class, exhibit multiple actions that are beneficial for the treatment of type 2 diabetic (T2D) patients, including improvement of glucose-induced insulin secretion (GIIS). To gain additional insight into the role of cAMP in the disturbed stimulus-secretion coupling within the diabetic β-cell, we examined more thoroughly the relationship between changes in islet cAMP concentration and insulin release in the GK/Par rat model of T2D. Basal cAMP content in GK/Par islets was significantly higher, whereas their basal insulin release was not significantly different from that of Wistar (W) islets. Even in the presence of IBMX or GLP-1, their insulin release did not significantly change despite further enhanced cAMP accumulation in both cases. The high basal cAMP level most likely reflects an increased cAMP generation in GK/Par compared with W islets since 1) forskolin dose-dependently induced an exaggerated cAMP accumulation; 2) adenylyl cyclase (AC)2, AC3, and G(s)α proteins were overexpressed; 3) IBMX-activated cAMP accumulation was less efficient and PDE-3B and PDE-1C mRNA were decreased. Moreover, the GK/Par insulin release apparatus appears less sensitive to cAMP, since GK/Par islets released less insulin at submaximal cAMP levels and required five times more cAMP to reach a maximal secretion rate no longer different from W. GLP-1 was able to reactivate GK/Par insulin secretion so that GIIS became indistinguishable from that of W. The exaggerated cAMP production is instrumental, since GLP-1-induced GIIS reactivation was lost in the presence the AC blocker 2',5'-dideoxyadenosine. This GLP-1 effect takes place in the absence of any improvement of the [Ca(2+)](i) response and correlates with activation of the cAMP-dependent PKA-dependent pathway.

AVP-IC50 Pred: Multiple machine learning techniques-based prediction of peptide antiviral activity in terms of half maximal inhibitory concentration (IC50).

PubMed

Qureshi, Abid; Tandon, Himani; Kumar, Manoj

2015-11-01

Peptide-based antiviral therapeutics has gradually paved their way into mainstream drug discovery research. Experimental determination of peptides' antiviral activity as expressed by their IC50 values involves a lot of effort. Therefore, we have developed "AVP-IC50 Pred," a regression-based algorithm to predict the antiviral activity in terms of IC50 values (μM). A total of 759 non-redundant peptides from AVPdb and HIPdb were divided into a training/test set having 683 peptides (T(683)) and a validation set with 76 independent peptides (V(76)) for evaluation. We utilized important peptide sequence features like amino-acid compositions, binary profile of N8-C8 residues, physicochemical properties and their hybrids. Four different machine learning techniques (MLTs) namely Support vector machine, Random Forest, Instance-based classifier, and K-Star were employed. During 10-fold cross validation, we achieved maximum Pearson correlation coefficients (PCCs) of 0.66, 0.64, 0.56, 0.55, respectively, for the above MLTs using the best combination of feature sets. All the predictive models also performed well on the independent validation dataset and achieved maximum PCCs of 0.74, 0.68, 0.59, 0.57, respectively, on the best combination of feature sets. The AVP-IC50 Pred web server is anticipated to assist the researchers working on antiviral therapeutics by enabling them to computationally screen many compounds and focus experimental validation on the most promising set of peptides, thus reducing cost and time efforts. The server is available at http://crdd.osdd.net/servers/ic50avp. © 2015 Wiley Periodicals, Inc.

Modulation of adhesion-dependent cAMP signaling by echistatin and alendronate

NASA Technical Reports Server (NTRS)

Fong, J. H.; Ingber, D. E.

1996-01-01

We measured intracellular cAMP levels in cells during attachment and spreading on different extracellular matrix (ECM) proteins. Increases in cAMP were observed within minutes when cells attached to fibronectin, vitronectin, and a synthetic RGD-containing fibronectin peptide (Petite 2000), but not when they adhered to another integrin alpha nu beta 3 ligand, echistatin. Because echistatin also inhibits bone resorption, we measured the effects of adding another osteoporosis inhibitor, alendronate, in this system. Alendronate inhibited the cAMP increase induced by ligands that primarily utilize integrin alpha nu beta 3 (vitronectin, Peptite 2000), but not by fibronectin which can also use integrin alpha 5 beta 1. These results show that cell adhesion to ECM can increase intracellular cAPM levels and raise the possibility that inhibitors of osteoporosis may act, in part, by preventing activation of this pathway by integrins.

Mechanism of N6-threonylcarbamoyladenonsine (t(6)A) biosynthesis: isolation and characterization of the intermediate threonylcarbamoyl-AMP.

PubMed

Lauhon, Charles T

2012-11-06

Genetic and biochemical studies have recently implicated four proteins required in bacteria for the biosynthesis of the universal tRNA modified base N6-threonylcarbamoyl adenosine (t(6)A). In this work, t(6)A biosynthesis in Bacillus subtilis has been reconstituted in vitro and found to indeed require the four proteins YwlC (TsaC), YdiB (TsaE), YdiC (TsaB) and YdiE (TsaD). YwlC was found to catalyze the conversion of L-threonine, bicarbonate/CO(2) and ATP to give the intermediate L-threonylcarbamoyl-AMP (TC-AMP) and pyrophosphate as products. TC-AMP was isolated by HPLC and characterized by mass spectrometry and (1)H NMR. NMR analysis showed that TC-AMP decomposes to give AMP and a nearly equimolar mixture of L-threonine and 5-methyl-2-oxazolidinone-4-carboxylate as final products. Under physiological conditions (pH 7.5, 37 °C, 2 mM MgCl(2)), the half-life of TC-AMP was measured to be 3.5 min. Both YwlC (in the presence of pyrophosphatase) and its Escherichia coli homologue YrdC catalyze the formation of TC-AMP while producing only a small molar fraction of AMP. This suggests that CO(2) and not an activated form of bicarbonate is the true substrate for these enzymes. In the presence of pyrophosphate, both enzymes catalyze clean conversion of TC-AMP back to ATP. Purified TC-AMP is efficiently processed to t(6)A by the YdiBCE proteins in the presence of tRNA substrates. This reaction is ATP independent in vitro, despite the known ATPase activity of YdiB. The estimated rate of conversion of TC-AMP by YdiBCE to t(6)A is somewhat lower than the initial rate from L-threonine, bicarbonate and ATP, which together with the stability data, is consistent with previous studies that suggest channeling of this intermediate.

The Central Role of cAMP in Regulating Plasmodium falciparum Merozoite Invasion of Human Erythrocytes

PubMed Central

More, Kunal R.; Siddiqui, Faiza Amber; Pachikara, Niseema; Ramdani, Ghania; Langsley, Gordon; Chitnis, Chetan E.

2014-01-01

All pathogenesis and death associated with Plasmodium falciparum malaria is due to parasite-infected erythrocytes. Invasion of erythrocytes by P. falciparum merozoites requires specific interactions between host receptors and parasite ligands that are localized in apical organelles called micronemes. Here, we identify cAMP as a key regulator that triggers the timely secretion of microneme proteins enabling receptor-engagement and invasion. We demonstrate that exposure of merozoites to a low K+ environment, typical of blood plasma, activates a bicarbonate-sensitive cytoplasmic adenylyl cyclase to raise cytosolic cAMP levels and activate protein kinase A, which regulates microneme secretion. We also show that cAMP regulates merozoite cytosolic Ca2+ levels via induction of an Epac pathway and demonstrate that increases in both cAMP and Ca2+ are essential to trigger microneme secretion. Our identification of the different elements in cAMP-dependent signaling pathways that regulate microneme secretion during invasion provides novel targets to inhibit blood stage parasite growth and prevent malaria. PMID:25522250

Creativity and Technology in Mathematics: From Story Telling to Algorithmic with Op'Art

ERIC Educational Resources Information Center

Mercat, Christian; Filho, Pedro Lealdino; El-Demerdash, Mohamed

2017-01-01

This article describes some of the results of the European project mcSquared (http://mc2-project.eu/) regarding the use of Op'Art and optical illusion pieces as a tool to foster modeling and creative mathematical thinking in students. We present briefly the c-book technology and some results we got experimenting it. The Op'Art movement, with…

T-cell differentiation of multipotent hematopoietic cell line EML in the OP9-DL1 coculture system.

PubMed

Kutlesa, Snjezana; Zayas, Jennifer; Valle, Alexandra; Levy, Robert B; Jurecic, Roland

2009-08-01

Multipotent hematopoietic cell line EML can differentiate into myeloid, erythroid, megakaryocytic, and B-lymphoid lineages, but it remained unknown whether EML cells have T-cell developmental potential as well. The goal of this study was to determine whether the coculture with OP9 stromal cells expressing Notch ligand Delta-like 1 (OP9-DL1) could induce differentiation of EML cells into T-cell lineage. EML cells were cocultured with control OP9 or OP9-DL1 stromal cells in the presence of cytokines (stem cell factor, interleukin-7, and Fms-like tyrosine kinase 3 ligand). Their T-cell lineage differentiation was assessed through flow cytometry and reverse transcription polymerase chain reaction expression analysis of cell surface markers and genes characterizing and associated with specific stages of T-cell development. The phenotypic, molecular, and functional analysis has revealed that in EML/OP9-DL1 cocultures with cytokines, but not in control EML/OP9 cocultures, EML cell line undergoes T-cell lineage commitment and differentiation. In OP9-DL1 cocultures, EML cell line has differentiated into cells that 1) resembled double-negative, double-positive, and single-positive stages of T-cell development; 2) initiated expression of GATA-3, Pre-Talpha, RAG-1, and T-cell receptor-Vbeta genes; and 3) produced interferon-gamma in response to T-cell receptor stimulation. These results support the notion that EML cell line has the capacity for T-cell differentiation. Remarkably, induction of T-lineage gene expression and differentiation of EML cells into distinct stages of T-cell development were very similar to previously described T-cell differentiation of adult hematopoietic stem cells and progenitors in OP9-DL1 cocultures. Thus, EML/OP9-DL1 coculture could be a useful experimental system to study the role of particular genes in T-cell lineage specification, commitment, and differentiation.

Illuminating the Depths of the MagIC (Magnetics Information Consortium) Database

NASA Astrophysics Data System (ADS)

Koppers, A. A. P.; Minnett, R.; Jarboe, N.; Jonestrask, L.; Tauxe, L.; Constable, C.

2015-12-01

The Magnetics Information Consortium (http://earthref.org/MagIC/) is a grass-roots cyberinfrastructure effort envisioned by the paleo-, geo-, and rock magnetic scientific community. Its mission is to archive their wealth of peer-reviewed raw data and interpretations from magnetics studies on natural and synthetic samples. Many of these valuable data are legacy datasets that were never published in their entirety, some resided in other databases that are no longer maintained, and others were never digitized from the field notebooks and lab work. Due to the volume of data collected, most studies, modern and legacy, only publish the interpreted results and, occasionally, a subset of the raw data. MagIC is making an extraordinary effort to archive these data in a single data model, including the raw instrument measurements if possible. This facilitates the reproducibility of the interpretations, the re-interpretation of the raw data as the community introduces new techniques, and the compilation of heterogeneous datasets that are otherwise distributed across multiple formats and physical locations. MagIC has developed tools to assist the scientific community in many stages of their workflow. Contributors easily share studies (in a private mode if so desired) in the MagIC Database with colleagues and reviewers prior to publication, publish the data online after the study is peer reviewed, and visualize their data in the context of the rest of the contributions to the MagIC Database. From organizing their data in the MagIC Data Model with an online editable spreadsheet, to validating the integrity of the dataset with automated plots and statistics, MagIC is continually lowering the barriers to transforming dark data into transparent and reproducible datasets. Additionally, this web application generalizes to other databases in MagIC's umbrella website (EarthRef.org) so that the Geochemical Earth Reference Model (http://earthref.org/GERM/) portal, Seamount Biogeosciences

OP-Yield Version 1.00 user's guide

Treesearch

Martin W. Ritchie; Jianwei Zhang

2018-01-01

OP-Yield is a Microsoft Excel™ spreadsheet with 14 specified user inputs to derive custom yield estimates using the original Oliver and Powers (1978) functions as the foundation. It presents yields for ponderosa pine (Pinus ponderosa Lawson & C. Lawson) plantations in northern California. The basic model forms for dominantand...

The Vida Verde Women's Co-Op: Brazilian Immigrants Organizing to Promote Environmental and Social Justice

PubMed Central

Siqueira, Eduardo; Goldberg, Julia S.; Galvão, Heloisa; Chianelli, Mônica; Pirie, Alex

2009-01-01

We reviewed the key steps in the launch of the Vida Verde Women's Co-Op among Brazilian immigrant housecleaners in Somerville, MA. The co-op provides green housecleaning products, encourages healthy work practices, and promotes a sense of community among its members. We conducted in-depth interviews with 8 of the first co-op members, who reported a reduction in symptoms associated with the use of traditional cleaning agents and a new sense of mutual support. Critical to the co-op's success have been the supportive roles of its academic partners (Tufts University and the University of Massachusetts, Lowell), effective media outreach, and a focus on advancing social justice. Next steps include implementing a formal business plan and assessing the appropriateness of cooperatives in other industries. PMID:19890146

Amps particle accelerator definition study

NASA Technical Reports Server (NTRS)

Sellen, J. M., Jr.

1975-01-01

The Particle Accelerator System of the AMPS (Atmospheric, Magnetospheric, and Plasmas in Space) payload is a series of charged particle accelerators to be flown with the Space Transportation System Shuttle on Spacelab missions. In the configuration presented, the total particle accelerator system consists of an energetic electron beam, an energetic ion accelerator, and both low voltage and high voltage plasma acceleration devices. The Orbiter is illustrated with such a particle accelerator system.

21 CFR 862.1230 - Cyclic AMP test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862... measure the level of adenosine 3′, 5′-monophosphate (cyclic AMP) in plasma, urine, and other body fluids...

cAMP-dependent activation of protein kinase A attenuates respiratory syncytial virus-induced human airway epithelial barrier disruption

PubMed Central

Harford, Terri J.; Linfield, Debra T.; Altawallbeh, Ghaith; Midura, Ronald J.; Ivanov, Andrei I.; Piedimonte, Giovanni

2017-01-01

Airway epithelium forms a barrier to the outside world and has a crucial role in susceptibility to viral infections. Cyclic adenosine monophosphate (cAMP) is an important second messenger acting via two intracellular signaling molecules: protein kinase A (PKA) and the guanidine nucleotide exchange factor, Epac. We sought to investigate effects of increased cAMP level on the disruption of model airway epithelial barrier caused by RSV infection and the molecular mechanisms underlying cAMP actions. Human bronchial epithelial cells were infected with RSV-A2 and treated with either cAMP releasing agent, forskolin, or cAMP analogs. Structure and functions of the Apical Junctional Complex (AJC) were evaluated by measuring transepithelial electrical resistance and permeability to FITC-dextran, and determining localization of AJC proteins by confocal microscopy. Increased intracellular cAMP level significantly attenuated RSV-induced disassembly of AJC. These barrier-protective effects of cAMP were due to the activation of PKA signaling and did not involve Epac activity. Increased cAMP level reduced RSV-induced reorganization of the actin cytoskeleton, including apical accumulation of an essential actin-binding protein, cortactin, and inhibited expression of the RSV F protein. These barrier-protective and antiviral-function of cAMP signaling were evident even when cAMP level was increased after the onset of RSV infection. Taken together, our study demonstrates that cAMP/PKA signaling attenuated RSV-induced disruption of structure and functions of the model airway epithelial barrier by mechanisms involving the stabilization of epithelial junctions and inhibition of viral biogenesis. Improving our understanding of the mechanisms involved in RSV-induced epithelial dysfunction and viral pathogenesis will help to develop novel anti-viral therapeutic approaches. PMID:28759570

Protein kinase Cδ differentially regulates cAMP-dependent translocation of NTCP and MRP2 to the plasma membrane

PubMed Central

Park, Se Won; Schonhoff, Christopher M.; Webster, Cynthia R. L.

2012-01-01

Cyclic AMP stimulates translocation of Na+/taurocholate cotransporting polypeptide (NTCP) from the cytosol to the sinusoidal membrane and multidrug resistance-associated protein 2 (MRP2) to the canalicular membrane. A recent study suggested that protein kinase Cδ (PKCδ) may mediate cAMP-induced translocation of Ntcp and Mrp2. In addition, cAMP has been shown to stimulate NTCP translocation in part via Rab4. The aim of this study was to determine whether cAMP-induced translocation of NTCP and MRP2 require kinase activity of PKCδ and to test the hypothesis that cAMP-induced activation of Rab4 is mediated via PKCδ. Studies were conducted in HuH-NTCP cells (HuH-7 cells stably transfected with NTCP). Transfection of cells with wild-type PKCδ increased plasma membrane PKCδ and NTCP and increased Rab4 activity. Paradoxically, overexpression of kinase-dead dominant-negative PKCδ also increased plasma membrane PKCδ and NTCP as well as Rab4 activity. Similar results were obtained in PKCδ knockdown experiments, despite a decrease in total PKCδ. These results raised the possibility that plasma membrane localization rather than kinase activity of PKCδ is necessary for NTCP translocation and Rab4 activity. This hypothesis was supported by results showing that rottlerin, which has previously been shown to inhibit cAMP-induced membrane translocation of PKCδ and NTCP, inhibited cAMP-induced Rab4 activity. In addition, LY294002 (a phosphoinositide-3-kinase inhibitor), which has been shown to inhibit cAMP-induced NTCP translocation, also inhibited cAMP-induced PKCδ translocation. In contrast to the results with NTCP, cAMP-induced MRP2 translocation was inhibited in cells transfected with DN-PKCδ and small interfering RNA PKCδ. Taken together, these results suggest that the plasma membrane localization rather than kinase activity of PKCδ plays an important role in cAMP-induced NTCP translocation and Rab4 activity, whereas the kinase activity of PKCδ is necessary for cAMP

Protein kinase Cδ differentially regulates cAMP-dependent translocation of NTCP and MRP2 to the plasma membrane.

PubMed

Park, Se Won; Schonhoff, Christopher M; Webster, Cynthia R L; Anwer, M Sawkat

2012-09-01

Cyclic AMP stimulates translocation of Na(+)/taurocholate cotransporting polypeptide (NTCP) from the cytosol to the sinusoidal membrane and multidrug resistance-associated protein 2 (MRP2) to the canalicular membrane. A recent study suggested that protein kinase Cδ (PKCδ) may mediate cAMP-induced translocation of Ntcp and Mrp2. In addition, cAMP has been shown to stimulate NTCP translocation in part via Rab4. The aim of this study was to determine whether cAMP-induced translocation of NTCP and MRP2 require kinase activity of PKCδ and to test the hypothesis that cAMP-induced activation of Rab4 is mediated via PKCδ. Studies were conducted in HuH-NTCP cells (HuH-7 cells stably transfected with NTCP). Transfection of cells with wild-type PKCδ increased plasma membrane PKCδ and NTCP and increased Rab4 activity. Paradoxically, overexpression of kinase-dead dominant-negative PKCδ also increased plasma membrane PKCδ and NTCP as well as Rab4 activity. Similar results were obtained in PKCδ knockdown experiments, despite a decrease in total PKCδ. These results raised the possibility that plasma membrane localization rather than kinase activity of PKCδ is necessary for NTCP translocation and Rab4 activity. This hypothesis was supported by results showing that rottlerin, which has previously been shown to inhibit cAMP-induced membrane translocation of PKCδ and NTCP, inhibited cAMP-induced Rab4 activity. In addition, LY294002 (a phosphoinositide-3-kinase inhibitor), which has been shown to inhibit cAMP-induced NTCP translocation, also inhibited cAMP-induced PKCδ translocation. In contrast to the results with NTCP, cAMP-induced MRP2 translocation was inhibited in cells transfected with DN-PKCδ and small interfering RNA PKCδ. Taken together, these results suggest that the plasma membrane localization rather than kinase activity of PKCδ plays an important role in cAMP-induced NTCP translocation and Rab4 activity, whereas the kinase activity of PKCδ is necessary for

Connected vehicle pilot deployment program phase 1, concept of operations (ConOps) – Tampa (THEA).

DOT National Transportation Integrated Search

2016-02-01

This document describes the Concept of Operations (ConOps) for the Tampa Hillsborough Expressway Authority (THEA) Connected Vehicle (CV) Pilot Deployment. This ConOps describes the current state of operations, establishes the reasons for change, and ...

The beautiful side of IC 335

NASA Image and Video Library

2017-12-08

Hubble sees a galaxy 60 million light-years away This new NASA/ESA Hubble Space Telescope image shows the galaxy IC 335 in front of a backdrop of distant galaxies. IC 335 is part of a galaxy group containing three other galaxies, and located in the Fornax Galaxy Cluster 60 million light-years away. As seen in this image, the disk of IC 335 appears edge-on from the vantage point of Earth. This makes it harder for astronomers to classify it, as most of the characteristics of a galaxy’s morphology — the arms of a spiral or the bar across the center — are only visible on its face. Still, the 45 000 light-year-long galaxy could be classified as an S0 type. These lenticular galaxies are an intermediate state in galaxy morphological classification schemes between true spiral and elliptical galaxies. They have a thin stellar disk and a bulge, like spiral galaxies, but in contrast to typical spiral galaxies they have used up most of the interstellar medium. Only a few new stars can be created out of the material that is left and the star formation rate is very low. Hence, the population of stars in S0 galaxies consists mainly of aging stars, very similar to the star population in elliptical galaxies. As S0 galaxies have only ill-defined spiral arms they are easily mistaken for elliptical galaxies if they are seen inclined face-on or edge-on as IC 335 here. And indeed, despite the morphological differences between S0 and elliptical class galaxies, they share some common characteristics, like typical sizes and spectral features. Both classes are also deemed "early-type" galaxies, because they are evolving passively. However, while elliptical galaxies may be passively evolving when we observe them, they have usually had violent interactions with other galaxies in their past. In contrast, S0 galaxies are either aging and fading spiral galaxies, which never had any interactions with other galaxies, or they are the aging result of a single merger between two spiral galaxies

One Stop Post Op cardiac surgery recovery--a proven success.

PubMed

Joyce, L; Pandolph, P

2001-01-01

The One Stop Post Op model for open heart surgery recovery is an innovative approach to post op care utilized in only a few facilities in the country. This model calls for an integration of acute ICU and step-down phases of care, thus changing the paradigm for nursing care of the open heart surgery patient. Typically, hospitals incur inefficiencies transferring the patient through multiple levels of care, thus resulting in a "disconnect" as new caregivers relearn the patient's care requirements and special needs. The construction of a "one stop" unit allows the patient to remain stationary while the service level changes to accommodate changing care needs. The cardiac "one stop" model is similar to the LDRP concept for obstetrical care. The One Stop Post Op patient rooms are designed to accommodate every level of patient acuity. All rooms meet the regulations for critical care room design, however this is where the aesthetic similarity ends. The patient environment looks more like hotel rooms rather than the traditional ICU setting. Cabinets designed to cover medical gases, in the room's private bathrooms and comfortable furnishings help to create a patient focused environment conducive to recovery. This model has been utilized by several facilities and has demonstrated clear clinical and economic advantages for patients, families, and health care providers. Implementing an open heart surgery (OHS) program presents the opportunity for several community based hospitals to challenge the way they have been providing patient care and establish an innovative approach to post surgery patient care. The One Stop Post Op cardiovascular recovery unit is designed to receive the OHS patient directly from the operating room and to be the "care unit" for the patient's entire stay. Patient flow, quality monitoring and caregiver acceptance in this unit requires new paradigms from the traditional two or three step post OHS care delivery process. The One Stop Post Op model focuses

Sensitivity of GBM cells to cAMP agonist-mediated apoptosis correlates with CD44 expression and agonist resistance with MAPK signaling.

PubMed

Daniel, Paul M; Filiz, Gulay; Mantamadiotis, Theo

2016-12-01

In some cell types, activation of the second messenger cAMP leads to increased expression of proapoptotic Bim and subsequent cell death. We demonstrate that suppression of the cAMP pathway is a common event across many cancers and that pharmacological activation of cAMP in glioblastoma (GBM) cells leads to enhanced BIM expression and apoptosis in specific GBM cell types. We identified the MAPK signaling axis as the determinant of cAMP agonist sensitivity in GBM cells, with high MAPK activity corresponding to cAMP resistance and low activity corresponding to sensitization to cAMP-induced apoptosis. Sensitive cells were efficiently killed by cAMP agonists alone, while targeting both the cAMP and MAPK pathways in resistant GBM cells resulted in efficient apoptosis. We also show that CD44 is differentially expressed in cAMP agonist-sensitive and -resistant cells. We thus propose that CD44 may be a useful biomarker for distinguishing tumors that may be sensitive to cAMP agonists alone or cAMP agonists in combination with other pathway inhibitors. This suggests that using existing chemotherapeutic compounds in combination with existing FDA-approved cAMP agonists may fast track trials toward improved therapies for difficult-to-treat cancers, such as GBM.

Pendrin protein abundance in the kidney is regulated by nitric oxide and cAMP.

PubMed

Thumova, Monika; Pech, Vladimir; Froehlich, Otto; Agazatian, Diana; Wang, Xiaonan; Verlander, Jill W; Kim, Young Hee; Wall, Susan M

2012-09-15

Pendrin is a Cl(-)/HCO(3)(-) exchanger, expressed in the apical regions of some intercalated cell subtypes, and is critical in the pressor response to angiotensin II. Since angiotensin type 1 receptor inhibitors reduce renal pendrin protein abundance in mice in vivo through a mechanism that is dependent on nitric oxide (NO), we asked if NO modulates renal pendrin expression in vitro and explored the mechanism by which it occurs. Thus we quantified pendrin protein abundance by confocal fluorescent microscopy in cultured mouse cortical collecting ducts (CCDs) and connecting tubules (CNTs). After overnight culture, CCDs maintain their tubular structure and maintain a solute gradient when perfused in vitro. Pendrin protein abundance increased 67% in CNT and 53% in CCD when NO synthase was inhibited (N(G)-nitro-L-arginine methyl ester, 100 μM), while NO donor (DETA NONOate, 200 μM) application reduced pendrin protein by ∼33% in the CCD and CNT. When CNTs were cultured in the presence of the guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (10 μM), NO donors did not alter pendrin abundance. Conversely, pendrin protein abundance rose when cAMP content was increased by the application of an adenylyl cyclase agonist (forskolin, 10 μM), a cAMP analog (8-bromo-cAMP, 1 mM), or a phosphodiesterase inhibitor (BAY60-7550, 50 μM). Since NO reduces cellular cAMP in the CNT, we asked if NO reduces pendrin abundance by reducing cAMP. With blockade of cGMP-stimulated phosphodiesterase II, NO did not alter pendrin protein abundance. We conclude that NO acts through cAMP to reduce pendrin total protein abundance by enhancing cAMP degradation.

Pendrin protein abundance in the kidney is regulated by nitric oxide and cAMP

PubMed Central

Thumova, Monika; Pech, Vladimir; Froehlich, Otto; Agazatian, Diana; Wang, Xiaonan; Verlander, Jill W.; Kim, Young Hee

2012-01-01

Pendrin is a Cl−/HCO3− exchanger, expressed in the apical regions of some intercalated cell subtypes, and is critical in the pressor response to angiotensin II. Since angiotensin type 1 receptor inhibitors reduce renal pendrin protein abundance in mice in vivo through a mechanism that is dependent on nitric oxide (NO), we asked if NO modulates renal pendrin expression in vitro and explored the mechanism by which it occurs. Thus we quantified pendrin protein abundance by confocal fluorescent microscopy in cultured mouse cortical collecting ducts (CCDs) and connecting tubules (CNTs). After overnight culture, CCDs maintain their tubular structure and maintain a solute gradient when perfused in vitro. Pendrin protein abundance increased 67% in CNT and 53% in CCD when NO synthase was inhibited (NG-nitro-l-arginine methyl ester, 100 μM), while NO donor (DETA NONOate, 200 μM) application reduced pendrin protein by ∼33% in the CCD and CNT. When CNTs were cultured in the presence of the guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (10 μM), NO donors did not alter pendrin abundance. Conversely, pendrin protein abundance rose when cAMP content was increased by the application of an adenylyl cyclase agonist (forskolin, 10 μM), a cAMP analog (8-bromo-cAMP, 1 mM), or a phosphodiesterase inhibitor (BAY60-7550, 50 μM). Since NO reduces cellular cAMP in the CNT, we asked if NO reduces pendrin abundance by reducing cAMP. With blockade of cGMP-stimulated phosphodiesterase II, NO did not alter pendrin protein abundance. We conclude that NO acts through cAMP to reduce pendrin total protein abundance by enhancing cAMP degradation. PMID:22811483

Transcription activation mediated by a cyclic AMP receptor protein from Thermus thermophilus HB8.

PubMed

Shinkai, Akeo; Kira, Satoshi; Nakagawa, Noriko; Kashihara, Aiko; Kuramitsu, Seiki; Yokoyama, Shigeyuki

2007-05-01

The extremely thermophilic bacterium Thermus thermophilus HB8, which belongs to the phylum Deinococcus-Thermus, has an open reading frame encoding a protein belonging to the cyclic AMP (cAMP) receptor protein (CRP) family present in many bacteria. The protein named T. thermophilus CRP is highly homologous to the CRP family proteins from the phyla Firmicutes, Actinobacteria, and Cyanobacteria, and it forms a homodimer and interacts with cAMP. CRP mRNA and intracellular cAMP were detected in this strain, which did not drastically fluctuate during cultivation in a rich medium. The expression of several genes was altered upon disruption of the T. thermophilus CRP gene. We found six CRP-cAMP-dependent promoters in in vitro transcription assays involving DNA fragments containing the upstream regions of the genes exhibiting decreased expression in the CRP disruptant, indicating that the CRP is a transcriptional activator. The consensus T. thermophilus CRP-binding site predicted upon nucleotide sequence alignment is 5'-(C/T)NNG(G/T)(G/T)C(A/C)N(A/T)NNTCACAN(G/C)(G/C)-3'. This sequence is unique compared with the known consensus binding sequences of CRP family proteins. A putative -10 hexamer sequence resides at 18 to 19 bp downstream of the predicted T. thermophilus CRP-binding site. The CRP-regulated genes found in this study comprise clustered regularly interspaced short palindromic repeat (CRISPR)-associated (cas) ones, and the genes of a putative transcriptional regulator, a protein containing the exonuclease III-like domain of DNA polymerase, a GCN5-related acetyltransferase homolog, and T. thermophilus-specific proteins of unknown function. These results suggest a role for cAMP signal transduction in T. thermophilus and imply the T. thermophilus CRP is a cAMP-responsive regulator.

International Space Agency CIO Forum Industrial Control System (ICS) and Cyber

NASA Technical Reports Server (NTRS)

Powell, Robert

2017-01-01

This briefing covers Industrial Control System (ICS) best practices for enhancing cyber protection. The briefing provides a very high-level overview of best practices currently being pursued by NASA as well as by other US government agencies such as NIST and DHS ICS-CERT. All information presented in this slide deck is publicly available and no sensitive information is provided in these slides. These slides will be used to generate discussion around best practices within the international community in the area of ICS cyber protections.

Neurological basis of AMP-dependent thermoregulation and its relevance to central and peripheral hyperthermia

PubMed Central

Muzzi, Mirko; Blasi, Francesco; Masi, Alessio; Coppi, Elisabetta; Traini, Chiara; Felici, Roberta; Pittelli, Maria; Cavone, Leonardo; Pugliese, Anna Maria; Moroni, Flavio; Chiarugi, Alberto

2013-01-01

Therapeutic hypothermia is of relevance to treatment of increased body temperature and brain injury, but drugs inducing selective, rapid, and safe cooling in humans are not available. Here, we show that injections of adenosine 5′-monophosphate (AMP), an endogenous nucleotide, promptly triggers hypothermia in mice by directly activating adenosine A1 receptors (A1R) within the preoptic area (POA) of the hypothalamus. Inhibition of constitutive degradation of brain extracellular AMP by targeting ecto 5′-nucleotidase, also suffices to prompt hypothermia in rodents. Accordingly, sensitivity of mice and rats to the hypothermic effect of AMP is inversely related to their hypothalamic 5′-nucleotidase activity. Single-cell electrophysiological recording indicates that AMP reduces spontaneous firing activity of temperature-insensitive neurons of the mouse POA, thereby retuning the hypothalamic thermoregulatory set point towards lower temperatures. Adenosine 5′-monophosphate also suppresses prostaglandin E2-induced fever in mice, having no effects on peripheral hyperthermia triggered by dioxymetamphetamine (ecstasy) overdose. Together, data disclose the role of AMP, 5′-nucleotidase, and A1R in hypothalamic thermoregulation, as well and their therapeutic relevance to treatment of febrile illness. PMID:23093068

Connected vehicle pilot deployment program phase 1, concept of operations (ConOps) - New York City.

DOT National Transportation Integrated Search

2016-04-08

This document describes the Concept of Operations (ConOps) for the New York City Department of Transportation (NYC) Connected Vehicle Pilot Deployment (CVPD) Project. This ConOps describes the current state of operations, establishes the reasons for ...

AGB stars as tracers to IC 1613 evolution.

NASA Astrophysics Data System (ADS)

Hashemi, S. A.; Javadi, A.; van Loon, J. Th.

We are going to apply AGB stars to find star formation history for IC 1613 galaxy; this a new and simple method that works well for nearby galaxies. IC 1613 is a Local Group dwarf irregular galaxy that is located at distance of 750 kpc, a gas rich and isolated dwarf galaxy that has a low foreground extinction. We use the long period variable stars (LPVs) that represent the very final stage of evolution of stars with low and intermediate mass at the AGB phase and are very luminous and cool so that they emit maximum brightness in near-infrared bands. Thus near-infrared photometry with using stellar evolutionary models help us to convert brightness to birth mass and age and from this drive star formation history of the galaxy. We will use the luminosity distribution of the LPVs to reconstruct the star formation history-a method we have successfully applied in other Local Group galaxies. Our analysis shows that the IC 1613 has had a nearly constant star formation rate, without any dominant star formation episode.

Monoacylglycerol lipase inhibition by organophosphorus compounds leads to elevation of brain 2-arachidonoylglycerol and the associated hypomotility in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quistad, Gary B.; Klintenberg, Rebecka; Caboni, Pierluigi

2006-02-15

Three components of the cannabinoid system are sensitive to selected organophosphorus (OP) compounds: monoacylglycerol (MAG) lipase that hydrolyzes the major endogenous agonist 2-arachidonoylglycerol (2-AG); fatty acid amide hydrolase (FAAH) that cleaves the agonist anandamide present in smaller amounts; the CB1 receptor itself. This investigation considers which component of the cannabinoid system is the most likely contributor to OP-induced hypomotility in mice. Structure-activity studies by our laboratory and others rule against major involvement of a direct toxicant-CB1 receptor interaction for selected OPs. Attention was therefore focused on the OP sensitivities of MAG lipase and FAAH, assaying 19 structurally diverse OP chemicalsmore » (pesticides, their metabolites and designer compounds) for in vitro inhibition of both enzymes. Remarkably high potency and low selectivity is observed with three O-alkyl (C{sub 1}, C{sub 2}, C{sub 3}) alkylphosphonofluoridates (C{sub 8}, C{sub 12}) (IC50 0.60-3.0 nM), five S-alkyl (C{sub 5}, C{sub 7}, C{sub 9}) and alkyl (C{sub 1}, C{sub 12}) benzodioxaphosphorin oxides (IC50 0.15-5.7 nM) and one OP insecticide metabolite (chlorpyrifos oxon, IC50 34-40 nM). In ip-treated mice, the OPs at 1-30 mg/kg more potently inhibit brain FAAH than MAG lipase, but FAAH inhibition is not correlated with hypomotility. However, the alkylphosphonofluoridate-treated mice show dose-dependent increases in severity of hypomotility, inhibition of MAG lipase activity and elevation of 2-AG. Moderate to severe hypomotility is accompanied by 64 to 86% MAG lipase inhibition and about 6-fold elevation of brain 2-AG level. It therefore appears that OP-induced MAG lipase inhibition leads to elevated 2-AG and the associated hypomotility.« less

cAMP dependent and independent regulation of thyroglobulin synthesis by two clones of the OVNIS 6H thyroid cell line.

PubMed

Aouani, A; Hovsépian, S; Fayet, G

1987-07-01

The hormonal regulation of thyroglobulin synthesis has been studied using two independent clones of the OVNIS 6H cell line. Insulin, hydrocortisone and TSH were able to stimulate thyroglobulin synthesis, whereas transferrin, somatostatin and glycyl-histidyl-lysine were without effect. Insulin stimulated thyroglobulin synthesis without affecting cAMP production. Hydrocortisone, when combined with insulin was a stimulator too; this stimulation was not accompanied by an increase in cAMP. TSH alone was unable to stimulate either cAMP or thyroglobulin synthesis. The stimulatory effect of TSH on thyroglobulin synthesis took place only when combined with insulin or insulin plus hydrocortisone, and was mediated by cAMP. Consequently, insulin and hydrocortisone stimulated thyroglobulin synthesis by cAMP-independent mechanisms, whereas TSH acted via the cAMP system. Forskolin mimicked TSH effects on cAMP and thyroglobulin synthesis. Calf serum inhibited cAMP and thyroglobulin production. Optimal cAMP and thyroglobulin synthesis as well as TSH responsiveness were obtained in serum-free medium supplemented with 5 micrograms/ml insulin, 100 nM hydrocortisone and 1 mU/ml TSH.

Use of optical technique for inspection of warpage of IC packages

NASA Astrophysics Data System (ADS)

Toh, Siew-Lok; Chau, Fook S.; Ong, Sim Heng

2001-06-01

The packaging of IC packages has changed over the years, form dual-in-line, wire-bond, and pin-through-hole in printed wiring board technologies in the 1970s to ball grid array, chip scale and surface mount technologies in the 1990s. Reliability has been a big problem for manufacturers for some moisture-sensitive packages. One of the potential problems in plastic IC packages is moisture-induced popcorn effect which can arise during the reflow process. Shearography is a non-destructive inspection technique that may be used to detect the delamination and warpage of IC packages. It is non-contacting and permits a full-field observation of surface displacement derivatives. Another advantage of this technique is that it is able to give the real-time formation of the fringes which indicate flaws in the IC package under real-time simulation condition of Surface Mount Technology (SMT) IR reflow profile. It is extremely fast and convenient to study the true behavior of the packaging deformation during the SMT process. It can be concluded that shearography has the potential for the real- time detection, in situ and non-destructive inspection of IC packages during the surface mount process.

Student Definitions of Intercultural Competence (IC)--Are They Context-Specific?

ERIC Educational Resources Information Center

Binder, Nadine; Odag, Ozen; Leiser, Anne; Ludders, Lisa; Kedzior, Karina Karolina

2018-01-01

Higher education institutions increasingly seek to promote students' intercultural competence (IC), yet its conceptualization remains a challenge. The first aim of this study was to explore how a purposive sample of n = 77 domestic, undergraduate students at a public university in Germany define IC. The second aim was to assess to what extent such…

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

Regulation of cAMP on the first mitotic cell cycle of mouse embryos.

PubMed

Yu, Aiming; Zhang, Zhe; Bi, Qiang; Sun, Bingqi; Su, Wenhui; Guan, Yifu; Mu, Runqing; Miao, Changsheng; Zhang, Jie; Yu, Bingzhi

2008-03-01

Mitosis promoting factor (MPF) plays a central role during the first mitosis of mouse embryo. We demonstrated that MPF activity increased when one-cell stage mouse embryo initiated G2/M transition following the decrease of cyclic adenosine 3', 5'-monophosphate (cAMP) and cAMP-dependent protein kinase (PKA) activity. When cAMP and PKA activity increases again, MPF activity decreases and mouse embryo starts metaphase-anaphase transition. In the downstream of cAMP/PKA, there are some effectors such as polo-like kinase 1 (Plk1), Cdc25, Mos (mitogen-activated protein kinase kinase kinase), MEK (mitogen-activated protein kinase kinase), mitogen-activated protein kinase (MAPK), Wee1, anaphase-promoting complex (APC), and phosphoprotein phosphatase that are involved in the regulation of MPF activity. Here, we demonstrated that following activation of MPF, MAPK activity was steady, whereas Plk1 activity fluctuated during the first cell cycle. Plk1 activity was the highest at metaphase and decreased at metaphase-anaphase transition. Further, we established a mathematical model using Gepasi algorithm and the simulation was in agreement with the experimental data. Above all the evidences, we suggested that cAMP and PKA might be the upstream factors which were included in the regulation of the first cell cycle development of mouse embryo. Copyright 2007 Wiley-Liss, Inc.

The effect of adenosine 5'-monophosphate (AMP) on tenderness, microstructure and chemical-physical index of duck breast meat.

PubMed

Wang, Daoying; Deng, Shaoying; Zhang, Muhan; Geng, Zhiming; Sun, Chong; Bian, Huan; Xu, Weimin; Zhu, Yongzhi; Liu, Fang; Wu, Haihong

2016-03-30

Adenosine 5'-monophosphate (AMP) is often used in meat and poultry soups as a flavor enhancer (flavor modifier), or as food additives for specific nutritional purposes. Our previous research as well as evidence from others showed that actomyosin could be dissociated into myosin and actin by AMP in extracted muscle solution. However, there is no report available on the application of AMP to dissociate actomyosin and to improve meat tenderness. The objectives of this study were to evaluate the effect of AMP on duck meat tenderness and other quality traits and to explore the mechanism of the action of AMP on meat tenderness. Duck breast muscle was treated with 0, 10, 20, 30, 40 mmol L(-1) AMP at 5 °C for 10 h and examined for shear force, microstructure, actomyosin dissociation, myofibril fragmentation index (MFI), pH, water content, cooking loss, CIE* color (L*, a*, b*), inosine monophosphate (IMP) and free amino acid (FAA) contents. Results showed that shear force, cooking loss, L* and b* of the muscles significantly decreased after AMP treatment (P < 0.05); actomyosin dissociation, MFI, pH, water content, fiber diameter, sarcomere length, IMP and ammonia significantly increased (P < 0.05); no significant change in a* or other FAA content was observed (P > 0.05), and muscle shrinkage in transverse and longitudinal directions were restrained after AMP treatment. The results suggest that AMP could notably improve meat tenderness, and this effect was probably mainly through increasing muscle pH, promoting actomyosin dissociation and disrupting the Z-line; meanwhile, the conversion of AMP to IMP may contribute to the flavor of meat. © 2015 Society of Chemical Industry.

Preparing for High Technology: Successful Co-op Strategies. Research and Development Series No. 263.

ERIC Educational Resources Information Center

Franchak, Stephen J.; Smith, O. H. Michael

This document has been prepared to assist program administrators and practitioners in planning and implementing cooperative (co-op) programs in high technology occupational areas. Information focuses on the key elements, strategies, and procedures of successful co-op programs. The guide contains nine chapters and is based on a review of the…

GTP-Binding Proteins Inhibit cAMP Activation of Chloride Channels in Cystic Fibrosis Airway Epithelial Cells

NASA Astrophysics Data System (ADS)

Schwiebert, Erik M.; Kizer, Neil; Gruenert, Dieter C.; Stanton, Bruce A.

1992-11-01

Cystic fibrosis (CF) is a genetic disease characterized, in part, by defective regulation of Cl^- secretion by airway epithelial cells. In CF, cAMP does not activate Cl^- channels in the apical membrane of airway epithelial cells. We report here whole-cell patch-clamp studies demonstrating that pertussis toxin, which uncouples heterotrimeric GTP-binding proteins (G proteins) from their receptors, and guanosine 5'-[β-thio]diphosphate, which prevents G proteins from interacting with their effectors, increase Cl^- currents and restore cAMP-activated Cl^- currents in airway epithelial cells isolated from CF patients. In contrast, the G protein activators guanosine 5'-[γ-thio]triphosphate and AlF^-_4 reduce Cl^- currents and inhibit cAMP from activating Cl^- currents in normal airway epithelial cells. In CF cells treated with pertussis toxin or guanosine 5'-[β-thio]diphosphate and in normal cells, cAMP activates a Cl^- conductance that has properties similar to CF transmembrane-conductance regulator Cl^- channels. We conclude that heterotrimeric G proteins inhibit cAMP-activated Cl^- currents in airway epithelial cells and that modulation of the inhibitory G protein signaling pathway may have the therapeutic potential for improving cAMP-activated Cl^- secretion in CF.

Industry-Oriented Laboratory Development for Mixed-Signal IC Test Education

ERIC Educational Resources Information Center

Hu, J.; Haffner, M.; Yoder, S.; Scott, M.; Reehal, G.; Ismail, M.

2010-01-01

The semiconductor industry is lacking qualified integrated circuit (IC) test engineers to serve in the field of mixed-signal electronics. The absence of mixed-signal IC test education at the collegiate level is cited as one of the main sources for this problem. In response to this situation, the Department of Electrical and Computer Engineering at…

30 CFR 57.22241 - Advance face boreholes (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Boreholes shall be drilled in such a manner to insure that the advancing face will not accidently break into... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Advance face boreholes (I-C mines). 57.22241... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22241 Advance face boreholes (I-C mines...

30 CFR 57.22241 - Advance face boreholes (I-C mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Advance face boreholes (I-C mines). 57.22241... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22241 Advance face boreholes (I-C mines). (a) Boreholes shall be drilled at least 25 feet in advance of a face whenever the work place is...

30 CFR 57.22241 - Advance face boreholes (I-C mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Advance face boreholes (I-C mines). 57.22241... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22241 Advance face boreholes (I-C mines). (a) Boreholes shall be drilled at least 25 feet in advance of a face whenever the work place is...

30 CFR 57.22241 - Advance face boreholes (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Advance face boreholes (I-C mines). 57.22241... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22241 Advance face boreholes (I-C mines). (a) Boreholes shall be drilled at least 25 feet in advance of a face whenever the work place is...

30 CFR 57.22241 - Advance face boreholes (I-C mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Advance face boreholes (I-C mines). 57.22241... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22241 Advance face boreholes (I-C mines). (a) Boreholes shall be drilled at least 25 feet in advance of a face whenever the work place is...

Upregulated Op18/stathmin activity causes chromosomal instability through a mechanism that evades the spindle assembly checkpoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmfeldt, Per; Sellin, Mikael E.; Gullberg, Martin, E-mail: Martin.Gullberg@molbiol.umu.se

2010-07-15

Op18/stathmin (Op18) is a microtubule-destabilizing protein that is phosphorylation-inactivated during mitosis and its normal function is to govern tubulin subunit partitioning during interphase. Human tumors frequently overexpress Op18 and a tumor-associated Q18{yields}E mutation has been identified that confers hyperactivity, destabilizes spindle microtubules, and causes mitotic aberrancies, polyploidization, and chromosome loss in K562 leukemia cells. Here we determined whether wild-type and mutant Op18 have the potential to cause chromosomal instability by some means other than interference with spindle assembly, and thereby bypassing the spindle assembly checkpoint. Our approach was based on Op18 derivatives with distinct temporal order of activity during mitosis,more » conferred either by differential phosphorylation inactivation or by anaphase-specific degradation through fusion with the destruction box of cyclin B1. We present evidence that excessive Op18 activity generates chromosomal instability through interference occurring subsequent to the metaphase-to-anaphase transition, which reduces the fidelity of chromosome segregation to spindle poles during anaphase. Similar to uncorrected merotelic attachment, this mechanism evades detection by the spindle assembly checkpoint and thus provides an additional route to chromosomal instability.« less

Induction of chinook salmon growth hormone promoter activity by the adenosine 3',5'-monophosphate (cAMP)-dependent pathway involves two cAMP-response elements with the CGTCA motif and the pituitary-specific transcription factor Pit-1.

PubMed

Wong, A O; Le Drean, Y; Liu, D; Hu, Z Z; Du, S J; Hew, C L

1996-05-01

In this study, the functional role of two cAMP-response elements (CRE) in the promoter of the chinook salmon GH gene and their interactions with the transcription factor Pit-1 in regulating GH gene expression were examined. A chimeric construct of the chloramphenicol acetyltransferase (CAT) reporter gene with the CRE-containing GH promoter (pGH.CAT) was transiently transfected into primary cultures of rainbow trout pituitary cells. The expression of CAT activity was stimulated by an adenylate cyclase activator forskolin as well as a membrane-permeant cAMP analog 8-bromo-cAMP. Furthermore, these stimulatory responses were inhibited by a protein kinase A inhibitor H89, suggesting that these CREs are functionally coupled to the adenylate cyclase-cAMP-protein kinase A cascade. This hypothesis is supported by parallel studies using GH4ZR7 cells, a rat pituitary cell line stably transfected with dopamine D2 receptors. In this cell line, D2 receptor activation is known to inhibit adenylate cyclase activity and cAMP synthesis. Stimulation with a nonselective dopamine agonist, apomorphine, or a D2-specific agonist, Ly171555, suppressed the expression of pGH.CAT in GH4ZR7 cells, and this inhibition was blocked by simultaneous treatment with forskolin. These results indicate that inhibition of the cAMP-dependent pathway reduces the basal promoter activity of the CRE-containing pGH.CAT. The functionality of these CREs was further confirmed by deletion analysis and site-specific mutagenesis. In trout pituitary cells, the cAMP inducibility of pGH.CAT was inhibited after deleting the CRE-containing sequence from the GH promoter. When the CRE-containing sequence was cloned into a CAT construct with a viral thymidine kinase promoter, a significant elevation of cAMP inducibility was observed. This stimulatory response, however, was abolished by mutating the core sequence, CGTCA, in these CREs, suggesting that these cis-acting elements confer cAMP inducibility to the salmon GH gene

cAMP Level Modulates Scleral Collagen Remodeling, a Critical Step in the Development of Myopia

PubMed Central

Liu, Shufeng; Fang, Fang; Lu, Runxia; Lu, Chanyi; Zheng, Min; An, Jianhong; Xu, Hongjia; Zhao, Fuxin; Chen, Jiang-fan; Qu, Jia; Zhou, Xiangtian

2013-01-01

The development of myopia is associated with decreased ocular scleral collagen synthesis in humans and animal models. Collagen synthesis is, in part, under the influence of cyclic adenosine monophosphate (cAMP). We investigated the associations between cAMP, myopia development in guinea pigs, and collagen synthesis by human scleral fibroblasts (HSFs). Form-deprived myopia (FDM) was induced by unilateral masking of guinea pig eyes. Scleral cAMP levels increased selectively in the FDM eyes and returned to normal levels after unmasking and recovery. Unilateral subconjunctival treatment with the adenylyl cyclase (AC) activator forskolin resulted in a myopic shift accompanied by reduced collagen mRNA levels, but it did not affect retinal electroretinograms. The AC inhibitor SQ22536 attenuated the progression of FDM. Moreover, forskolin inhibited collagen mRNA levels and collagen secretion by HSFs. The inhibition was reversed by SQ22536. These results demonstrate a critical role of cAMP in control of myopia development. Selective regulation of cAMP to control scleral collagen synthesis may be a novel therapeutic strategy for preventing and treating myopia. PMID:23951163

The Co-Op/Disadvantaged Job Success Project. Final Report. Vocational-Technical Education Research Report.

ERIC Educational Resources Information Center

Welch, Frederick G.; Erwin, Michael

The Co-op/Disadvantaged First-Job Success Project was organized to provide inservice training to vocational teachers and cooperative education coordinators who work with inner city disadvantaged youth in the south central region of Pennsylvania. The project was organized in a manner that allowed project staff, co-op coordinators, and teachers to…

Reduced sensitivity of the hepatic adenylate cyclase-cyclic AMP system to glucagon during sustained hormonal stimulation.

PubMed Central

DeRubertis, F R; Craven, P

1976-01-01

Hormone-induced desensitization of hormonal regulation of cyclic AMP (cAMP) content has been described in a number of tissues. In the present study, we examined responses of rat liver to glucagon after periods of sustained exposure to the hormone in vivo and in vitro. In intact anesthetized rats infused with glucagon (50 ng/min) for 1 h or more and in liver slices incubated with the hormone (10 muM) for this period, hepatic cAMP responsiveness to glucagon was significantly blunted compared with that of tissue exposed to the hormone for shorter periods. The reduction in hepatic cAMP responsiveness to glucagon appeared to be fully expressed by 2 h. With the doses of hormone employed, the sequential alterations in hepatic responsiveness seemed to be limited to the cAMP system, since other parameters of glucagon action did not wane with time. Diminished hepatic cAMP responsiveness during sustained hormonal exposure could not be attributed to decreased glucagon availability, accelerated extracellular release of cAMP, hepatic ATP depletion, or enhanced phosphodiesterase activity. Studies in vitro suggested that modulation of the cAMP response occurred at the level of adenylate cyclase (AC). During sustained exposure of hepatic slices to glucagon, reductions in glucagon-responsive AC correlated temporally with those in cAMP and both changes were reversible. Alterations in glucagon-responsive AC were demonstrated over a wide range of ATP (10 muM-0.1 mM) and glucagon (10 nM-5 MM) concentrations in the cyclase reaction mixture, and appeared to be a noncompetitive phenomenon relative to glucagon. Maximal NaF-responsive AC did not fall concomitantly with time. Thus, the reduction in glucagon-responsive AC was probably not related to a reduction in the catalytic unit of the enzyme, but could have been due to an alteration in glucagon binding to its receptor sites, or in the coupling mechanism involved in transmission of the hormonal signal to the catalytic unit. Images PMID

c-di-AMP: An Essential Molecule in the Signaling Pathways that Regulate the Viability and Virulence of Gram-Positive Bacteria

PubMed Central

Fahmi, Tazin; Port, Gary C.

2017-01-01

Signal transduction pathways enable organisms to monitor their external environment and adjust gene regulation to appropriately modify their cellular processes. Second messenger nucleotides including cyclic adenosine monophosphate (c-AMP), cyclic guanosine monophosphate (c-GMP), cyclic di-guanosine monophosphate (c-di-GMP), and cyclic di-adenosine monophosphate (c-di-AMP) play key roles in many signal transduction pathways used by prokaryotes and/or eukaryotes. Among the various second messenger nucleotides molecules, c-di-AMP was discovered recently and has since been shown to be involved in cell growth, survival, and regulation of virulence, primarily within Gram-positive bacteria. The cellular level of c-di-AMP is maintained by a family of c-di-AMP synthesizing enzymes, diadenylate cyclases (DACs), and degradation enzymes, phosphodiesterases (PDEs). Genetic manipulation of DACs and PDEs have demonstrated that alteration of c-di-AMP levels impacts both growth and virulence of microorganisms. Unlike other second messenger molecules, c-di-AMP is essential for growth in several bacterial species as many basic cellular functions are regulated by c-di-AMP including cell wall maintenance, potassium ion homeostasis, DNA damage repair, etc. c-di-AMP follows a typical second messenger signaling pathway, beginning with binding to receptor molecules to subsequent regulation of downstream cellular processes. While c-di-AMP binds to specific proteins that regulate pathways in bacterial cells, c-di-AMP also binds to regulatory RNA molecules that control potassium ion channel expression in Bacillus subtilis. c-di-AMP signaling also occurs in eukaryotes, as bacterially produced c-di-AMP stimulates host immune responses during infection through binding of innate immune surveillance proteins. Due to its existence in diverse microorganisms, its involvement in crucial cellular activities, and its stimulating activity in host immune responses, c-di-AMP signaling pathway has become an

Influence of polychlorinated aromatic compounds on the biotransformation and toxicity of organophosphorus pesticides (OP) to the Daphnia magna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonkopii, V.; Zagrebin, A.; Sherstneva, L.

1995-12-31

The effect of different polychlorinated aromatics (DDT, Aroclor 1254, certain polychlorinated biphenyls and dibenzofurans) on the toxicity of OP (DDVP paraoxon, malaoxon) to Daphnia magna was studied. Pretreatment of daphnids with chlorinated compounds during 72 hours in nontoxic concentrations (1/5--1/20 CL{sub 50}) has been shown to reduce the toxicity of OP for hydrobionts. For study of influence of chlorinated compounds on biotransformation of OP the activity of enzymes which are hydrolyzing the OP was investigated in Daphnia`s homogenates or microsomes. The activity of carboxylesterase (tributyrinase, aliesterase) and arylesterase (phosphorylphosphatase) with usage as substrates accordingly {alpha}-naphthylacetate and paraoxon was measured. Besidesmore » that the activity of cholinesterase with application of propionylthiocholine as substrate was determined. After polychlorinated aromatic compounds treatment of daphnids activities of both aryl-and carboxylesterase increased markedly. It decreased the inhibition of Daphnia`s cholinesterase caused by incubation with OP in concentrations 0.5--1.0 CL{sub 50}. Thus the induction by chlorinate aromatics of OP metabolizing enzymes seems to play the important role in reduction of OP toxicity to Daphnia magna. Perhaps the aryl- and carboxylesterase of Daphnia can be used as biomarkers of pollution by polychlorinated aromatics in water.« less

Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes.

PubMed

Laurent, C E; Cardinal, R; Rousseau, G; Vermeulen, M; Bouchard, C; Wilkinson, M; Armour, J A; Bouvier, M

2001-02-01

To corroborate alterations in the functional responses to beta-adrenergic receptor (beta-AR) stimulation with changes in beta-AR signaling in failing cardiomyocytes, contractile and L-type Ca(2+) current responses to isoproterenol along with stimulated cAMP generation were compared among cardiomyocytes isolated from canines with tachycardia-induced heart failure or healthy hearts. The magnitude of shortening of failing cardiomyocytes was significantly depressed (by 22 +/- 4.4%) under basal conditions, and the maximal response to isoproterenol was significantly reduced (by 45 +/- 18%). Similar results were obtained when the responses in the rate of contraction and rate of relaxation to isoproterenol were considered. The L-type Ca(2+) current amplitude measured in failing cardiomyocytes under basal conditions was unchanged, but the responses to isoproterenol were significantly reduced compared with healthy cells. Isoproterenol-stimulated cAMP generation was similar in sarcolemmal membranes derived from the homogenates of failing (45 +/- 6.8) and healthy cardiomyocytes (52 +/- 8.5 pmol cAMP. mg protein(-1). min(-1)). However, stimulated cAMP generation was found to be significantly reduced when the membranes were derived from the homogenates of whole tissue (failing: 67 +/- 8.1 vs. healthy: 140 +/- 27.8 pmol cAMP. mg protein(-1). min(-1)). Total beta-AR density was not reduced in membranes derived from either whole tissue or isolated cardiomyocyte homogenates, but the beta(1)/beta(2) ratio was significantly reduced in the former (failing: 45/55 vs. healthy: 72/28) without being altered in the latter (failing: 72/28, healthy: 77/23). We thus conclude that, in tachycardia-induced heart failure, reduction in the functional responses of isolated cardiomyocytes to beta-AR stimulation may be attributed to alterations in the excitation-contraction machinery rather than to limitation of cAMP generation.

T-cell differentiation of multipotent hematopoietic cell line EML in the OP9-DL1 coculture system

PubMed Central

Kutleša, Snježana; Zayas, Jennifer; Valle, Alexandra; Levy, Robert B.; Jurecic, Roland

2011-01-01

Objective Multipotent hematopoietic cell line EML can differentiate into myeloid, erythroid, megakaryocytic, and B-lymphoid lineages, but it remained unknown whether EML cells have T-cell developmental potential as well. The goal of this study was to determine whether the coculture with OP9 stromal cells expressing Notch ligand Delta-like 1 (OP9-DL1) could induce differentiation of EML cells into T-cell lineage. Materials and Methods EML cells were cocultured with control OP9 or OP9-DL1 stromal cells in the presence of cytokines (stem cell factor, interleukin-7, and Fms-like tyrosine kinase 3 ligand). Their T-cell lineage differentiation was assessed through flow cytometry and reverse transcription polymerase chain reaction expression analysis of cell surface markers and genes characterizing and associated with specific stages of T-cell development. Results The phenotypic, molecular, and functional analysis has revealed that in EML/OP9-DL1 cocultures with cytokines, but not in control EML/OP9 cocultures, EML cell line undergoes T-cell lineage commitment and differentiation. In OP9-DL1 cocultures, EML cell line has differentiated into cells that 1) resembled double-negative, double-positive, and single-positive stages of T-cell development; 2) initiated expression of GATA-3, Pre-Tα, RAG-1, and T-cell receptor – Vβ genes; and 3) produced interferon-γ in response to T-cell receptor stimulation. Conclusions These results support the notion that EML cell line has the capacity for T-cell differentiation. Remarkably, induction of T-lineage gene expression and differentiation of EML cells into distinct stages of T-cell development were very similar to previously described T-cell differentiation of adult hematopoietic stem cells and progenitors in OP9-DL1 cocultures. Thus, EML/OP9-DL1 coculture could be a useful experimental system to study the role of particular genes in T-cell lineage specification, commitment, and differentiation. PMID:19447159

Stable, sensitive, fluorescence-based method for detecting cAMP.

PubMed

Hesley, Jayne; Daijo, Janet; Ferguson, Anne T

2002-09-01

cAMP is a universal secondary messenger that connects changes in the extracellular environment, as detected by cell surface receptors, to transcriptional changes in the nucleus. Since cAMP-mediated signal transduction plays a role in critical cell functions and human diseases, monitoring its activity can aid in understanding these responses and the process of drug discovery. This report examines the performance of a fluorescence-based competitive immunoassay in 384-well microplate format. Using purified cAMP as a competitor the estimated detection limit was determined to be 0.1 nM and Z'-factor was greater than 0.83, which indicates that the assay is of high quality and one of the most sensitive assays currently on the market. Of note, the results obtained were similar whether the reaction was allowed to proceed for 10 min or up to 60 min. Next, HEK 293 cells were treated with the promiscuous adenylate cyclase activator, forskolin, and the beta-adrenoceptor agonist, isoproterenol. The resultant average EC50 values were 11 microM and 123 nM, respectively, which correspond to those found in the literature. Together, these results demonstrate that this assay is afast, accurate, non-radioactive method that is ideal for high-throughput screening.

Protective features of resveratrol on human spermatozoa cryopreservation may be mediated through 5' AMP-activated protein kinase activation.

PubMed

Shabani Nashtaei, M; Amidi, F; Sedighi Gilani, M A; Aleyasin, A; Bakhshalizadeh, Sh; Naji, M; Nekoonam, S

2017-03-01

Biochemical and physical modifications during the freeze-thaw process adversely influence the restoration of energy-dependent sperm functions required for fertilization. Resveratrol, a phytoalexin, has been introduced to activate 5' AMP-activated protein kinase which is a cell energy sensor and a cell metabolism regulator. The cryoprotection of resveratrol on sperm cryoinjury via activation of AMP-activated protein kinase also remains to be elucidated. Our aim, thus, was to investigate: (i) the presence and intracellular localization of AMP-activated protein kinase protein; (ii) whether resveratrol may exert a protective effect on certain functional properties of fresh and post-thaw human spermatozoa through modulation of AMP-activated protein kinase. Spermatozoa from normozoospermic men were incubated with or without different concentrations of Compound C as an AMP-activated protein kinase inhibitor or resveratrol as an AMP-activated protein kinase activator for different lengths of time and were then cryopreserved. AMP-activated protein kinase is expressed essentially in the entire flagellum and the post-equatorial region. Viability of fresh spermatozoa was not significantly affected by the presence of Compound C or resveratrol. However, although Compound C caused a potent inhibition of spermatozoa motility parameters, resveratrol did not induce negative effect, except a significant reduction in motility at 25 μm for 1 h. Furthermore, resveratrol significantly increased AMP-activated protein kinase phosphorylation and mitochondrial membrane potential and decreased reactive oxygen species and apoptosis-like changes in frozen-thawed spermatozoa. Nevertheless, it was not able to compensate decreased sperm viability and motility parameters following cryopreservation. In contrast, Compound C showed opposite effects to resveratrol on AMP-activated protein kinase phosphorylation, reactive oxygen species, apoptosis-like changes, mitochondrial membrane potential, and

Role of exchange protein directly activated by cAMP (EPAC1) in breast cancer cell migration and apoptosis.

PubMed

Kumar, Naveen; Gupta, Sonal; Dabral, Surbhi; Singh, Shailja; Sehrawat, Seema

2017-06-01

Despite the current progress in cancer research and therapy, breast cancer remains the leading cause of mortality among half a million women worldwide. Migration and invasion of cancer cells are associated with prevalent tumor metastasis as well as high mortality. Extensive studies have powerfully established the role of prototypic second messenger cAMP and its two ubiquitously expressed intracellular cAMP receptors namely the classic protein kinaseA/cAMP-dependent protein kinase (PKA) and the more recently discovered exchange protein directly activated by cAMP/cAMP-regulated guanine nucleotide exchange factor (EPAC/cAMP-GEF) in cell migration, cell cycle regulation, and cell death. Herein, we performed the analysis of the Cancer Genome Atlas (TCGA) dataset to evaluate the essential role of cAMP molecular network in breast cancer. We report that EPAC1, PKA, and AKAP9 along with other molecular partners are amplified in breast cancer patients, indicating the importance of this signaling network. To evaluate the functional role of few of these proteins, we used pharmacological modulators and analyzed their effect on cell migration and cell death in breast cancer cells. Hence, we report that inhibition of EPAC1 activity using pharmacological modulators leads to inhibition of cell migration and induces cell death. Additionally, we also observed that the inhibition of EPAC1 resulted in disruption of its association with the microtubule cytoskeleton and delocalization of AKAP9 from the centrosome as analyzed by in vitro imaging. Finally, this study suggests for the first time the mechanistic insights of mode of action of a primary cAMP-dependent sensor, Exchange protein activated by cAMP 1 (EPAC1), via its interaction with A-kinase anchoring protein 9 (AKAP9). This study provides a new cell signaling cAMP-EPAC1-AKAP9 direction to the development of additional biotherapeutics for breast cancer.

Seizure Suppression by High Temperature via cAMP Modulation in Drosophila.

PubMed

Saras, Arunesh; Tanouye, Mark A

2016-10-13

Bang-sensitive (BS) Drosophila mutants display characteristic seizure-like activity (SLA) and paralysis after mechanical shock . After high-frequency electrical stimulation (HFS) of the brain, they generate robust seizures at very low threshold voltage. Here we report an important phenomenon, which effectively suppresses SLA in BS mutants. High temperature causes seizure suppression in all BS mutants (para bss1 , eas, sda) examined in this study. This effect is fully reversible and flies show complete recovery from BS paralysis once the temperature effect is nullified. High temperature induces an increase in seizure threshold after a brief pulse of heat shock (HS). By genetic screening, we identified the involvement of cAMP in the suppression of seizures by high temperature. We propose that HS induces adenylyl cyclase which in turn increases cAMP concentration which eventually suppresses seizures in mutant flies. In summary, we describe an unusual phenomenon, where high temperature can suppress SLA in flies by modulating cAMP concentration. Copyright © 2016 Saras and Tanouye.

Resveratrol ameliorates aging-related metabolic phenotypes by inhibiting cAMP phosphodiesterases.

PubMed

Park, Sung-Jun; Ahmad, Faiyaz; Philp, Andrew; Baar, Keith; Williams, Tishan; Luo, Haibin; Ke, Hengming; Rehmann, Holger; Taussig, Ronald; Brown, Alexandra L; Kim, Myung K; Beaven, Michael A; Burgin, Alex B; Manganiello, Vincent; Chung, Jay H

2012-02-03

Resveratrol, a polyphenol in red wine, has been reported as a calorie restriction mimetic with potential antiaging and antidiabetogenic properties. It is widely consumed as a nutritional supplement, but its mechanism of action remains a mystery. Here, we report that the metabolic effects of resveratrol result from competitive inhibition of cAMP-degrading phosphodiesterases, leading to elevated cAMP levels. The resulting activation of Epac1, a cAMP effector protein, increases intracellular Ca(2+) levels and activates the CamKKβ-AMPK pathway via phospholipase C and the ryanodine receptor Ca(2+)-release channel. As a consequence, resveratrol increases NAD(+) and the activity of Sirt1. Inhibiting PDE4 with rolipram reproduces all of the metabolic benefits of resveratrol, including prevention of diet-induced obesity and an increase in mitochondrial function, physical stamina, and glucose tolerance in mice. Therefore, administration of PDE4 inhibitors may also protect against and ameliorate the symptoms of metabolic diseases associated with aging. Copyright © 2012 Elsevier Inc. All rights reserved.

Gαs regulates Glucagon-Like Peptide 1 Receptor-mediated cyclic AMP generation at Rab5 endosomal compartment.

PubMed

Girada, Shravan Babu; Kuna, Ramya S; Bele, Shilpak; Zhu, Zhimeng; Chakravarthi, N R; DiMarchi, Richard D; Mitra, Prasenjit

2017-10-01

Upon activation, G protein coupled receptors (GPCRs) associate with heterotrimeric G proteins at the plasma membrane to initiate second messenger signaling. Subsequently, the activated receptor experiences desensitization, internalization, and recycling back to the plasma membrane, or it undergoes lysosomal degradation. Recent reports highlight specific cases of persistent cyclic AMP generation by internalized GPCRs, although the functional significance and mechanistic details remain to be defined. Cyclic AMP generation from internalized Glucagon-Like Peptide-1 Receptor (GLP-1R) has previously been reported from our laboratory. This study aimed at deciphering the molecular mechanism by which internalized GLP-R supports sustained cyclic AMP generation upon receptor activation in pancreatic beta cells. We studied the time course of cyclic AMP generation following GLP-1R activation with particular emphasis on defining the location where cyclic AMP is generated. Detection involved a novel GLP-1 conjugate coupled with immunofluorescence using specific endosomal markers. Finally, we employed co-immunoprecipitation as well as immunofluorescence to assess the protein-protein interactions that regulate GLP-1R mediated cyclic AMP generation at endosomes. Our data reveal that prolonged association of G protein α subunit Gαs with activated GLP-1R contributed to sustained cyclic AMP generation at Rab 5 endosomal compartment. The findings provide the mechanism of endosomal cyclic AMP generation following GLP-1R activation. We identified the specific compartment that serves as an organizing center to generate endosomal cyclic AMP by internalized activated receptor complex. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

iAMP-2L: a two-level multi-label classifier for identifying antimicrobial peptides and their functional types.

PubMed

Xiao, Xuan; Wang, Pu; Lin, Wei-Zhong; Jia, Jian-Hua; Chou, Kuo-Chen

2013-05-15

Antimicrobial peptides (AMPs), also called host defense peptides, are an evolutionarily conserved component of the innate immune response and are found among all classes of life. According to their special functions, AMPs are generally classified into ten categories: Antibacterial Peptides, Anticancer/tumor Peptides, Antifungal Peptides, Anti-HIV Peptides, Antiviral Peptides, Antiparasital Peptides, Anti-protist Peptides, AMPs with Chemotactic Activity, Insecticidal Peptides, and Spermicidal Peptides. Given a query peptide, how can we identify whether it is an AMP or non-AMP? If it is, can we identify which functional type or types it belong to? Particularly, how can we deal with the multi-type problem since an AMP may belong to two or more functional types? To address these problems, which are obviously very important to both basic research and drug development, a multi-label classifier was developed based on the pseudo amino acid composition (PseAAC) and fuzzy K-nearest neighbor (FKNN) algorithm, where the components of PseAAC were featured by incorporating five physicochemical properties. The novel classifier is called iAMP-2L, where "2L" means that it is a 2-level predictor. The 1st-level is to answer the 1st question above, while the 2nd-level is to answer the 2nd and 3rd questions that are beyond the reach of any existing methods in this area. For the conveniences of users, a user-friendly web-server for iAMP-2L was established at http://www.jci-bioinfo.cn/iAMP-2L. Copyright © 2013 Elsevier Inc. All rights reserved.

Structural insights into Cn-AMP1, a short disulfide-free multifunctional peptide from green coconut water.

PubMed

Santana, Mábio J; de Oliveira, Aline L; Queiroz Júnior, Luiz H K; Mandal, Santi M; Matos, Carolina O; Dias, Renata de O; Franco, Octavio L; Lião, Luciano M

2015-02-27

Multifunctional and promiscuous antimicrobial peptides (AMPs) can be used as an efficient strategy to control pathogens. However, little is known about the structural properties of plant promiscuous AMPs without disulfide bonds. CD and NMR were used to elucidate the structure of the promiscuous peptide Cn-AMP1, a disulfide-free peptide isolated from green coconut water. Data here reported shows that peptide structure is transitory and could be different according to the micro-environment. In this regard, Cn-AMP1 showed a random coil in a water environment and an α-helical structure in the presence of SDS-d25 micelles. Moreover, deuterium exchange experiments showed that Gly4, Arg5 and Met9 residues are less accessible to solvent, suggesting that flexibility and cationic charges seem to be essential for Cn-AMP1 multiple activities. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Global Role of Cyclic AMP Signaling in pH-Dependent Responses in Candida albicans.

PubMed

Hollomon, Jeffrey M; Grahl, Nora; Willger, Sven D; Koeppen, Katja; Hogan, Deborah A

2016-01-01

Candida albicans behaviors are affected by pH, an important environmental variable. Filamentous growth is a pH-responsive behavior, where alkaline conditions favor hyphal growth and acid conditions favor growth as yeast. We employed filamentous growth as a tool to study the impact of pH on the hyphal growth regulator Cyr1, and we report that downregulation of cyclic AMP (cAMP) signaling by acidic pH contributes to the inhibition of hyphal growth in minimal medium with GlcNAc. Ras1 and Cyr1 are generally required for efficient hyphal growth, and the effects of low pH on Ras1 proteolysis and GTP binding are consistent with diminished cAMP output. Active alleles of ras1 do not suppress the hyphal growth defect at low pH, while dibutyryl cAMP partially rescues filamentous growth at low pH in a cyr1 mutant. These observations are consistent with Ras1-independent downregulation of Cyr1 by low pH. We also report that extracellular pH leads to rapid and prolonged decreases in intracellular pH, and these changes may contribute to reduced cAMP signaling by reducing intracellular bicarbonate pools. Transcriptomics analyses found that the loss of Cyr1 at either acidic or neutral pH leads to increases in transcripts involved in carbohydrate catabolism and protein translation and glycosylation and decreases in transcripts involved in oxidative metabolism, fluconazole transport, metal transport, and biofilm formation. Other pathways were modulated in pH-dependent ways. Our findings indicate that cAMP has a global role in pH-dependent responses, and this effect is mediated, at least in part, through Cyr1 in a Ras1-independent fashion. IMPORTANCE Candida albicans is a human commensal and the causative agent of candidiasis, a potentially invasive and life-threatening infection. C. albicans experiences wide changes in pH during both benign commensalism (a common condition) and pathogenesis, and its morphology changes in response to this stimulus. Neutral pH is considered an

Global Role of Cyclic AMP Signaling in pH-Dependent Responses in Candida albicans

PubMed Central

Hollomon, Jeffrey M.; Grahl, Nora; Willger, Sven D.; Koeppen, Katja

2016-01-01

ABSTRACT Candida albicans behaviors are affected by pH, an important environmental variable. Filamentous growth is a pH-responsive behavior, where alkaline conditions favor hyphal growth and acid conditions favor growth as yeast. We employed filamentous growth as a tool to study the impact of pH on the hyphal growth regulator Cyr1, and we report that downregulation of cyclic AMP (cAMP) signaling by acidic pH contributes to the inhibition of hyphal growth in minimal medium with GlcNAc. Ras1 and Cyr1 are generally required for efficient hyphal growth, and the effects of low pH on Ras1 proteolysis and GTP binding are consistent with diminished cAMP output. Active alleles of ras1 do not suppress the hyphal growth defect at low pH, while dibutyryl cAMP partially rescues filamentous growth at low pH in a cyr1 mutant. These observations are consistent with Ras1-independent downregulation of Cyr1 by low pH. We also report that extracellular pH leads to rapid and prolonged decreases in intracellular pH, and these changes may contribute to reduced cAMP signaling by reducing intracellular bicarbonate pools. Transcriptomics analyses found that the loss of Cyr1 at either acidic or neutral pH leads to increases in transcripts involved in carbohydrate catabolism and protein translation and glycosylation and decreases in transcripts involved in oxidative metabolism, fluconazole transport, metal transport, and biofilm formation. Other pathways were modulated in pH-dependent ways. Our findings indicate that cAMP has a global role in pH-dependent responses, and this effect is mediated, at least in part, through Cyr1 in a Ras1-independent fashion. IMPORTANCE Candida albicans is a human commensal and the causative agent of candidiasis, a potentially invasive and life-threatening infection. C. albicans experiences wide changes in pH during both benign commensalism (a common condition) and pathogenesis, and its morphology changes in response to this stimulus. Neutral pH is considered an

Men Working on Mock-Up of S-IC Thrust Structure

NASA Technical Reports Server (NTRS)

1963-01-01

This photograph depicts Marshall Space Flight Center employees, James Reagin, machinist (top); Floyd McGinnis, machinist; and Ernest Davis, experimental test mechanic (foreground), working on a mock up of the S-IC thrust structure. The S-IC stage is the first stage, or booster, of the 364-foot long Saturn V rocket that ultimately took astronauts to the Moon. The S-IC stage, burned over 15 tons of propellant per second during its 2.5 minutes of operation to take the vehicle to a height of about 36 miles and to a speed of about 6,000 miles per hour. The stage was 138 feet long and 33 feet in diameter. Operating at maximum power, all five of the engines produced 7,500,000 pounds of thrust.

Distinct pools of cAMP centre on different isoforms of adenylyl cyclase in pituitary-derived GH3B6 cells.

PubMed

Wachten, Sebastian; Masada, Nanako; Ayling, Laura-Jo; Ciruela, Antonio; Nikolaev, Viacheslav O; Lohse, Martin J; Cooper, Dermot M F

2010-01-01

Microdomains have been proposed to explain specificity in the myriad of possible cellular targets of cAMP. Local differences in cAMP levels can be generated by phosphodiesterases, which control the diffusion of cAMP. Here, we address the possibility that adenylyl cyclases, the source of cAMP, can be primary architects of such microdomains. Distinctly regulated adenylyl cyclases often contribute to total cAMP levels in endogenous cellular settings, making it virtually impossible to determine the contribution of a specific isoform. To investigate cAMP dynamics with high precision at the single-isoform level, we developed a targeted version of Epac2-camps, a cAMP sensor, in which the sensor was tagged to a catalytically inactive version of the Ca(2+)-stimulable adenylyl cyclase 8 (AC8). This sensor, and less stringently targeted versions of Epac2-camps, revealed opposite regulation of cAMP synthesis in response to Ca(2+) in GH(3)B(6) pituitary cells. Ca(2+) release triggered by thyrotropin-releasing hormone stimulated the minor endogenous AC8 species. cAMP levels were decreased by inhibition of AC5 and AC6, and simultaneous activation of phosphodiesterases, in different compartments of the same cell. These findings demonstrate the existence of distinct adenylyl-cyclase-centered cAMP microdomains in live cells and open the door to their molecular micro-dissection.

Presence of ESBL/AmpC -Producing Escherichia coli in the Broiler Production Pyramid: A Descriptive Study

PubMed Central

Dierikx, Cindy M.; van der Goot, Jeanet A.; Smith, Hilde E.; Kant, Arie; Mevius, Dik J.

2013-01-01

Broilers and broiler meat products are highly contaminated with extended spectrum beta-lactamase (ESBL) or plasmid-mediated AmpC beta-lactamase producing Escherichia coli and are considered to be a source for human infections. Both horizontal and vertical transmission might play a role in the presence of these strains in broilers. As not much is known about the presence of these strains in the whole production pyramid, the epidemiology of ESBL/AmpC-producing E. coli in the Dutch broiler production pyramid was examined. Cloacal swabs of Grandparent stock (GPS) birds (one−/two-days (breed A and B), 18 and 31 weeks old (breed A)), one-day old Parent stock birds (breed A and B) and broiler chickens of increasing age (breed A) were selectively cultured to detect ESBL/AmpC-producing isolates. ESBL/AmpC-producing isolates were found at all levels in the broiler production pyramid in both broiler breeds examined. Prevalence was already relatively high at the top of the broiler production pyramid. At broiler farms ESBL/AmpC producing E. coli were still present in the environment of the poultry house after cleaning and disinfection. Feed samples taken in the poultry house also became contaminated with ESBL/AmpC producing E. coli after one or more production weeks. The prevalence of ESBL/AmpC-positive birds at broiler farms increased within the first week from 0–24% to 96–100% independent of the use of antibiotics and stayed 100% until slaughter. In GPS breed A, prevalence at 2 days, 18 weeks and 31 weeks stayed below 50% except when beta-lactam antibiotics were administered. In that case prevalence increased to 100%. Interventions minimizing ESBL/AmpC contamination in broilers should focus on preventing horizontal and vertical spread, especially in relation to broiler production farms. PMID:24244401

Ca2+-regulated-cAMP/PKA signaling in cardiac pacemaker cells links ATP supply to demand.

PubMed

Yaniv, Yael; Juhaszova, Magdalena; Lyashkov, Alexey E; Spurgeon, Harold A; Sollott, Steven J; Lakatta, Edward G

2011-11-01

In sinoatrial node cells (SANC), Ca(2+) activates adenylate cyclase (AC) to generate a high basal level of cAMP-mediated/protein kinase A (PKA)-dependent phosphorylation of Ca(2+) cycling proteins. These result in spontaneous sarcoplasmic-reticulum (SR) generated rhythmic Ca(2+) oscillations during diastolic depolarization, that not only trigger the surface membrane to generate rhythmic action potentials (APs), but, in a feed-forward manner, also activate AC/PKA signaling. ATP is consumed to pump Ca(2+) to the SR, to produce cAMP, to support contraction and to maintain cell ionic homeostasis. Since feedback mechanisms link ATP-demand to ATP production, we hypothesized that (1) both basal ATP supply and demand in SANC would be Ca(2+)-cAMP/PKA dependent; and (2) due to its feed-forward nature, a decrease in flux through the Ca(2+)-cAMP/PKA signaling axis will reduce the basal ATP production rate. O(2) consumption in spontaneous beating SANC was comparable to ventricular myocytes (VM) stimulated at 3 Hz. Graded reduction of basal Ca(2+)-cAMP/PKA signaling to reduce ATP demand in rabbit SANC produced graded ATP depletion (r(2)=0.96), and reduced O(2) consumption and flavoprotein fluorescence. Neither inhibition of glycolysis, selectively blocking contraction nor specific inhibition of mitochondrial Ca(2+) flux reduced the ATP level. Feed-forward basal Ca(2+)-cAMP/PKA signaling both consumes ATP to drive spontaneous APs in SANC and is tightly linked to mitochondrial ATP production. Interfering with Ca(2+)-cAMP/PKA signaling not only slows the firing rate and reduces ATP consumption, but also appears to reduce ATP production so that ATP levels fall. This distinctly differs from VM, which lack this feed-forward basal cAMP/PKA signaling, and in which ATP level remains constant when the demand changes. Published by Elsevier Ltd.

Exposure to organophosphate (OP) pesticides and health conditions in agricultural and non-agricultural workers from Maule, Chile

PubMed Central