bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Replication of Pathogenic and Nonpathogenic Strains of West Nile Virus within Astrocytes
Authors: Hussmann Katherine L. , Samuel Melanie A. , Kim Kwang S. , Diamond Michael S. , Fredericksen Brenda L.
Published: December 2012

The severity of West Nile virus (WNV) infection in immunocompetent animals is highly strain dependent, ranging from avirulent to highly neuropathogenic. Here, we investigate the nature of this strain-specific restriction by analyzing the replication of avirulent (WNV-MAD78) and highly virulent (WNV-NY) strains in neurons, astrocytes, and microvascular endothelial cells, which comprise the neurovascular unit within the central nervous system (CNS). We demonstrate that WNV-MAD78 replicated in and traversed brain microvascular endothelial cells as efficiently as WNV-NY. Likewise, similar levels of replication were detected in neurons. Thus, WNV-MAD78's nonneuropathogenic phenotype is not due to an intrinsic inability to replicate in key target cells within the CNS. In contrast, replication of WNV-MAD78 was delayed and reduced compared to that of WNV-NY in astrocytes. The reduced susceptibility of astrocytes to WNV-MAD78 was due to a delay in viral genome replication and an interferon-independent reduction in cell-to-cell spread. Together, our data suggest that astrocytes regulate WNV spread within the CNS and therefore are an attractive target for ameliorating WNV-induced neuropathology.
Herpesvirus Tegument Protein pUL37 Interacts with Dystonin/BPAG1 To Promote Capsid Transport on Microtubules during Egress
Authors: Pasdeloup David , McElwee Marion , Beilstein Frauke , Labetoulle Marc , Rixon Frazer J.
Published: December 2012

Herpes simplex virus 1 (HSV-1) is a neurotropic virus that travels long distances through cells using the microtubule network. Its 125-nm-diameter capsid is a large cargo which efficiently recruits molecular motors for movement. Upon entry, capsids reach the centrosome by minus-end-directed transport. From there, they are believed to reach the nucleus by plus-end-directed transport. Plus-end-directed transport is also important during egress, when capsids leave the nucleus to reach the site of envelopment in the cytoplasm. Although capsid interactions with dynein and kinesins have been described
in vitro
, the actual composition of the cellular machinery recruited by herpesviruses for capsid transport in infected cells remains unknown. Here, we identify the spectraplakin protein, dystonin/BPAG1, an important cytoskeleton cross-linker involved in microtubule-based transport, as a binding partner of the HSV-1 protein pUL37, which has been implicated in capsid transport. Viral replication is delayed in dystonin-depleted cells, and, using video microscopy of living infected cells, we show that dystonin depletion strongly inhibits capsid movement in the cytoplasm during egress. This study provides new insights into the cellular requirements for HSV-1 capsid transport and identifies dystonin as a nonmotor protein part of the transport machinery.
Emergence of a Norovirus GII.4 Strain Correlates with Changes in Evolving Blockade Epitopes
Authors: Lindesmith Lisa C. , Costantini Verónica , Swanstrom Jesica , Debbink Kari , Donaldson Eric F. , Vinjé Jan , Baric Ralph S.
Published: December 2012

The major capsid protein of norovirus GII.4 strains is evolving rapidly, resulting in epidemic strains with altered antigenicity. GII.4.2006 Minerva strains circulated at pandemic levels in 2006 and persisted at lower levels until 2009. In 2009, a new GII.4 variant, GII.4.2009 New Orleans, emerged and since then has become the predominant strain circulating in human populations. To determine whether changes in evolving blockade epitopes correlate with the emergence of the GII.4.2009 New Orleans strains, we compared the antibody reactivity of a panel of mouse monoclonal antibodies (MAbs) against GII.4.2006 and GII.4.2009 virus-like particles (VLPs). Both anti-GII.4.2006 and GII.4.2009 MAbs effectively differentiated the two strains by VLP-carbohydrate ligand blockade assay. Most of the GII.4.2006 MAbs preferentially blocked GII.4.2006, while all of the GII.4.2009 MAbs preferentially blocked GII.4.2009, although 8 of 12 tested blockade MAbs blocked both VLPs. Using mutant VLPs designed to alter predicted antigenic epitopes, binding of seven of the blockade MAbs was impacted by alterations in epitope A, identifying residues 294, 296, 297, 298, 368, and 372 as important antigenic sites in these strains. Convalescent-phase serum collected from a GII.4.2009 outbreak confirmed the immunodominance of epitope A, since alterations of epitope A affected serum reactivity by 40%. These data indicate that the GII.4.2009 New Orleans variant has evolved a key blockade epitope, possibly allowing for at least partial escape from protective herd immunity and provide epidemiological support for the utility of monitoring changes in epitope A in emergent strain surveillance.
Entry and Killing of Tetrahymena thermophila by Bacterially Produced Shiga Toxin
Authors: Stolfa Gino , Koudelka Gerald B.
Published: December 2012

Phage-encoded Shiga toxin (Stx) acts as a bacterial defense against the eukaryotic predator
Tetrahymena thermophila
. It is unknown how Stx enters
Tetrahymena
protozoa or how it kills them.
Tetrahymena
protozoa are phagocytotic; hence, Stx could gain entry to the cytoplasm through the oral apparatus or via endocytosis. We find that Stx2 can kill
T. thermophila
protozoa that lack an oral apparatus, indicating that Stx2 can enter these cells via endocytosis. As opposed to the lack of effect on mammalian phagocytes, Stx2 produced by bacteria encapsulated within phagocytotic vesicles is also capable of killing
Tetrahymena
. Addition of an excess of the carbohydrate binding subunits of Stx2 (StxB) and/or ricin (ricin B) blocks Stx2 cytotoxicity. Thus, regardless of whether Stx2 enters the cytoplasm by endocytosis or from the phagocytotic vesicle, this transport is mediated by a putative glycoconjugate receptor. Bacteriophage-mediated lysis of Stx-encoding bacteria is necessary for Stx toxicity in
Tetrahymena
; i.e., toxin released as a consequence of digestion of bacteria by
Tetrahymena
is harmless to the cell. This finding provides a rationale as to why the genes encoding Stx are found almost exclusively on bacteriophages; Stx must be released from the bacteria prior to the digestion of the cell, or it will not be able to exert its cytotoxic effect. It also suggests a reason why other bacterial exotoxins are also found only on temperate bacteriophages. Incubation of
Tetrahymena
with purified Stx2 decreases total protein synthesis. This finding indicates that, similar to mammalian cells, Stx2 kills
Tetrahymena
by inactivating its ribosomes.

IMPORTANCE
Tetrahymena
is a bacterial predator and a model for mammalian phagocytosis and intracellular vesicular trafficking. Phage-encoded exotoxins apparently have evolved for the purpose of bacterial antipredator defense. These exotoxins kill mammalian cells by inactivating universally conserved factors and/or pathways.
Tetrahymena
and susceptible mammalian cells are killed when exposed to bacteriophage-encoded Shiga toxin (Stx). Stx toxicity in mammalian cells requires Stx binding to the globotriaosyl ceramide (Gb3) receptor, followed by receptor-mediated endocytosis (RME). We show that, similar to mammalian cells, internalized Stx inhibits protein synthesis in
Tetrahymena
. Although
Tetrahymena
lacks Gb3, our results suggest that the cytotoxic effect of Stx on
Tetrahymena
is apparently mediated by a receptor, thereby arguing for the existence of RME in
Tetrahymena
. As opposed to the case with mammalian phagocytes, Stx produced by bacteria inside
Tetrahymena
is cytotoxic, suggesting that these cells may represent a “missing link” between unicellular eukaryotic bacterial predators and phagocytotic mammalian cells.
De Novo
Assembly of the Pneumocystis jirovecii Genome from a Single Bronchoalveolar Lavage Fluid Specimen from a Patient
Authors: Cissé Ousmane H. , Pagni Marco , Hauser Philippe M.
Published: December 2012

Pneumocystis jirovecii
is a fungus that causes severe pneumonia in immunocompromised patients. However, its study is hindered by the lack of an
in vitro
culture method. We report here the genome of
P. jirovecii
that was obtained from a single bronchoalveolar lavage fluid specimen from a patient. The major challenge was the
in silico
sorting of the reads from a mixture representing the different organisms of the lung microbiome. This genome lacks virulence factors and most amino acid biosynthesis enzymes and presents reduced GC content and size. Together with epidemiological observations, these features suggest that
P. jirovecii
is an obligate parasite specialized in the colonization of human lungs, which causes disease only in immune-deficient individuals. This genome sequence will boost research on this deadly pathogen.

IMPORTANCE
Pneumocystis
pneumonia is a major cause of mortality in patients with impaired immune systems. The availability of the
P. jirovecii
genome sequence allows new analyses to be performed which open avenues to solve critical issues for this deadly human disease. The most important ones are (i) identification of nutritional supplements for development of culture
in vitro
, which is still lacking 100 years after discovery of the pathogen; (ii) identification of new targets for development of new drugs, given the paucity of present treatments and emerging resistance; and (iii) identification of targets for development of vaccines.
Candida albicans Morphogenesis Is Not Required for Macrophage Interleukin 1β Production
Authors: Wellington Melanie , Koselny Kristy , Krysan Damian J.
Published: December 2012

The interaction of
Candida albicans
with macrophages induces the production of interleukin 1β (IL-1β) through inflammasome activation in a process that is required for host survival.
C. albicans
hypha formation has been linked to IL-1β production, but the question of whether hyphae are sufficient to trigger IL-1β production has not been examined directly. To address this question, a
C. albicans
library of 165 transcription factor deletion mutants was screened for strains with altered IL-1β production by lipopolysaccharide (LPS)-primed J774 cells, a murine macrophage-like cell line. Eight mutants with decreased and two mutants with increased IL-1β secretion were identified. In addition, 12 mutants with previously identified morphology deficits were found to induce IL-1β secretion to levels similar to those of the wild type. Examination of the morphology of both low and normal IL-1β-inducing mutants in macrophages revealed that two mutants (
upc2
Δ/
upc2
Δ and
ahr1
Δ/Δ mutants) were indistinguishable from the wild type with respect to morphology yet induced low levels of IL-1β; conversely, the
ndt80
Δ/Δ mutant was deficient for hypha formation but induced levels of IL-1β similar to those of the wild type. Transcription factor mutants deficient for IL-1β secretion also caused markedly lower levels of macrophage lysis. Similarly, the ability of a mutant to cause macrophage lysis was independent of its ability to form hyphae. Taken together, our observations indicate that the physical formation of hyphae is not sufficient to trigger IL-1β secretion or macrophage lysis and suggest that other mechanisms, such as pyroptosis, a caspase-1-dependent response to intracellular pathogens, may play a role in the interaction of macrophages with
C. albicans
.

IMPORTANCE
The ability of
Candida albicans
to transition from yeast to filamentous cells plays an important and complex role in pathogenesis. Recent results from a number of investigators indicate that the host responds to yeast and hyphal
C. albicans
differently. For example, a
C. albicans
mutant unable to form hyphae also fails to induce interleukin 1β (IL-1β) secretion from macrophages. We have identified
C. albicans
transcription factor mutants that have decreased IL-1β secretion but retain the ability to form hyphae in response to macrophages. In addition, these mutants cause significantly less macrophage lysis. These observations indicate that the physical presence of the hyphal structure in the macrophage is not sufficient to trigger IL-1β secretion nor does it cause physical lysis of the cell. Our data indicate that characteristics of hyphae separate from its physical morphology are responsible for triggering the release of IL-1β release and causing macrophage lysis. Since these observations are inconsistent with some current models, alternative mechanisms for the interaction of
C. albicans
with macrophages must be considered.
Biochemical and Structural Evidence in Support of a Coherent Model for the Formation of the Double-Helical Influenza A Virus Ribonucleoprotein
Authors: Ye Qiaozhen , Guu Tom S. Y. , Mata Douglas A. , Kuo Rei-Lin , Smith Bartram , Krug Robert M. , Tao Yizhi J.
Published: December 2012

Influenza A virions contain eight ribonucleoproteins (RNPs), each comprised of a negative-strand viral RNA, the viral polymerase, and multiple nucleoproteins (NPs) that coat the viral RNA. NP oligomerization along the viral RNA is mediated largely by a 28-amino-acid tail loop. Influenza viral RNPs, which serve as the templates for viral RNA synthesis in the nuclei of infected cells, are not linear but rather are organized in hairpin-like double-helical structures. Here we present results that strongly support a coherent model for the assembly of the double-helical influenza virus RNP structure. First, we show that NP self-associates much more weakly in the absence of RNA than in its presence, indicating that oligomerization is very limited in the cytoplasm. We also show that once NP has oligomerized, it can dissociate in the absence of bound RNA, but only at a very slow rate, indicating that the NP scaffold remains intact when viral RNA dissociates from NPs to interact with the polymerase during viral RNA synthesis. In addition, we identify a previously unknown NP-NP interface that is likely responsible for organizing the double-helical viral RNP structure. This identification stemmed from our observation that NP lacking the oligomerization tail loop forms monomers and dimers. We determined the crystal structure of this NP dimer, which reveals this new NP-NP interface. Mutation of residues that disrupt this dimer interface does not affect oligomerization of NPs containing the tail loop but does inactivate the ability of NPs containing the tail loop to support viral RNA synthesis in minigenome assays.

IMPORTANCE
Influenza A virus, the causative agent of human pandemics and annual epidemics, contains eight RNA gene segments. Each RNA segment assumes the form of a rod-shaped, double-helical ribonucleoprotein (RNP) that contains multiple copies of a viral protein, the nucleoprotein (NP), which coats the RNA segment along its entire length. Previous studies showed that NP molecules can polymerize via a structural element called the tail loop, but the RNP assembly process is poorly understood. Here we show that influenza virus RNPs are likely assembled from NP monomers, which polymerize through the tail loop only in the presence of viral RNA. Using X-ray crystallography, we identified an additional way that NP molecules interact with each other. We hypothesize that this new interaction is responsible for organizing linear, single-stranded influenza virus RNPs into double-helical structures. Our results thus provide a coherent model for the assembly of the double-helical influenza virus RNP structure.
CHOICES OF OPTIMAL MONETARY POLICY INSTRUMENTS UNDER THE FLOATING AND THE BASKET-PEG REGIMES
Authors: YOSHINO NAOYUKI , KAJI SAHOKO , ASONUMA TAMON
Published: December 2012

This paper determines whether adopting the basket-peg rather than the floating regime is optimal for emerging market countries. Under the basket-peg regime, there is a trade-off between practical usefulness and welfare losses associated with capital movements across countries. We develop a dynamic stochastic general equilibrium model for small open economies to derive a simple basket weight rule. Although this is suboptimal, we find it practical and easy to implement. With calibration using Singaporean and Thai data for 1997Q3–2006Q2 and comparison among cumulative losses associated with the policy instrument rules, we show that a commitment to the basket weight rule is superior to other instrument rules under the floating regime for small, open emerging market countries like Singapore and Thailand.
FOREIGN WORKERS AND WITHIN INDUSTRY DYNAMICS
Authors: SOON DOMINIC , THIA JANG PING
Published: December 2012

Using a services firm-level dataset for Singapore, we find that different services industries have different industry dynamics with regards to work-permit foreign workers (FWs). In the retail industry, higher FW use is associated with lower firm-level profitability. This suggests that greater industry consolidation through tighter FW allocation could improve overall productivity in the sector. On the other hand, greater FW use in the hotel industry is associated with higher firm-level productivity. This suggests that FWs represent a critical input that supports more productive firms in this tradable sector. Hence, for this sector, FW policy should be more accommodative.
MODELING INFLATION IN INDIA: THE ROLE OF MONEY
Authors: KUNDAN KISHOR N.
Published: December 2012

This paper studies the role of the real money gap — the deviation of real money balance from its long-run equilibrium level — for predicting inflation in India. Using quarterly data on manufacturing inflation from 1982 to 2007, we find that the real money gap is a significant predictor of inflation in India. Our results show that this variable is a better predictor of future inflation at quarterly horizon than the deviation of broad money growth from its target for the whole sample period. We also document a break in the overall predictability of inflation in the last quarter of 1995. We find that, except for the real money gap, the forecasting power of other predictors under study has declined considerably after 1995.
VARIATIONAL PROBLEM FOR THE FRENKEL AND THE BARGMANN–MICHEL–TELEGDI (BMT) EQUATIONS
Authors: DERIGLAZOV A. A.
Published: December 2012

We propose Lagrangian formulation for the particle with value of spin fixed within the classical theory. The Lagrangian is invariant under non-Abelian group of local symmetries. On this reason, all the initial spin variables turn out to be unobservable quantities. As the gauge-invariant variables for description of spin we can take either the Frenkel tensor or the Bargmann–Michel–Telegdi (BMT) vector. Fixation of spin within the classical theory implies O(ℏ)-corrections to the corresponding equations of motion.
HYPERCONJUGATION EFFECT ON THE STRUCTURAL STABILITY OF A TERT-BUTYL AND ITS DERIVED C4Hn(n = 4–10) ISOMERS
Authors: MENG YAN , TIAN CHUANJIN , WANG FENGTING , WANG ZHIGANG , JIN MINGXING , CHEN LEI , FENG WEI , DING DAJUN
Published: December 2012

The hyperconjugation effect on molecular structural stability is studied by performing first-principles calculations on the tert-butyl and its derived C 4 H n(n = 4–10) isomer structures. Four of the isomer structures with n = 7–10 were found to show hyperconjugation similar to that in the tert-butyl, with hyperconjugation orbital energies decreasing with the increase of the number of hydrogen atoms participating in the hyperconjugation (PIH). The distribution of charge carried by the PIH hydrogen atoms is uniform, which reveals a delocalization character in the electronic structures; and the PIH hydrogen atoms are found responsible for the main IR spectrum peak relating to C-H stretching vibration.
THEORETICAL STUDY ONHBeP-ANDHPBe-ANIONS USING MULTICONFIGURATION SECOND-ORDER PERTURBATION THEORY
Authors: LI WEN-ZUO , PEI YU-WEI , SUN CAI-XIA , LI QING-ZHONG , CHENG JIAN-BO
Published: December 2012

Some low-lying states of the nine-valence-electron systems HBeP-and HPBe-anions have been studied for the first time using three methods CASSCF, CASPT2 and B3LYP with the contracted atomic natural orbital (ANO) and cc-pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized at the CASSCF/ANO, CASPT2/ANO and B3LYP/cc-pVTZ levels. The potential energy curves of isomerization reactions between HBeP-and HPBe-were calculated as a function of HBeP bond angle. The ground and the first excited states of HBeP-are predicted to be X2Π and A2Σ+states, respectively. The X2Σ+and A2Π states of the linear HPBe-are both first-order saddle points because they have unique imaginary frequency. Two bent minima M1 and M2 were found along the 12A′ and 12A″ potential energy surfaces, respectively. The calculated results indicated that the ground-state HBeP-is linear, while the ground-state HPBe-is bent.
MOLECULAR SIMULATIONS OF NEOCARZINOSTATIN CHROMOPHORE RELEASE MECHANISM
Authors: YU HUI , ZHAO XI , FENG XIAN-LI , CHEN XUECHENG , BOROWIAK-PALEN EWA , HUANG XU-RI
Published: December 2012

Neocarzinostatin (NCS) is an antitumor chromophore carrier protein with many applications in clinical use such as drug delivery system; however, so far its chromophore-releasing mechanism remains unclear. In this contribution the process and pathway of the chromophore releasing from holoprotein are revealed by conventional molecular dynamics simulations and essential dynamics (ED) sampling method. The results are consistent with the model for ligand release proposed in [D. H. Chin et al., J Biol Chem281:16025, 2006]. The further analysis suggests that the conformational changes of loop 99–104 and motions of side-chain of residue Phe78 are important factors for chromophore release; the opening state of loop 99–104 is a precondition for the release of ligand.
Autophagy in endothelial progenitor cells is cytoprotective in hypoxic conditions
Authors: Wang Hai-Jie , Zhang Dan , Tan Yu-Zhen , Li Ting
Published: December 2012

Endothelial progenitor cells (EPCs) may be incorporated into local vessels to enhance angiogenesis within ischemic tissue. Recently, EPC transplantation has become a potential therapy for improving tissue function in cardiovascular disease. However, the mechanisms of proliferation, differentiation, and survival of EPCs in a hypoxic microenvironment remain unclear. In this study, CD34+VEGFR-2+ EPCs were isolated from mononuclear cells of human umbilical cord blood, and differentiation to endothelial cells was induced with VEGF. When EPC autophagy was inhibited with 3-methyladenine (3-MA) under normoxic conditions, proliferation and viability of the cells were decreased, and the cells failed to differentiate into endothelial cells. Under hypoxic conditions (1% O2), Beclin-1 expression of the cells was upregulated and both MDC-labeled and LC3-positive puncta and autophagic ultrastructures in the cells increased significantly. The number of lysosomes also increased in hypoxia-exposed cells. When autophagy was inhibited with 3-MA under hypoxic conditions, the number of apoptotic cells increased, and the number and size of lysosomes decreased. Conversely, apoptosis of the hypoxic EPCs was reduced when autophagy was induced by pretreatment with rapamycin. These results demonstrate that autophagy is involved in proliferation and differentiation of EPCs. Furthermore, hypoxia activates autophagy, promoting EPC survival by inhibiting apoptosis. Enhancing autophagy with hypoxic preconditioning may be beneficial for survival of the transplanted EPCs in a local hypoxic environment.
Reduced adult endothelial cell EphB4 function promotes venous remodeling
Authors: Jadlowiec Caroline C. , Feigel Amanda , Yang Chenzi , Feinstein Aaron J. , Kim Susun T. , Collins Michael J. , Kondo Yuka , Muto Akihito , Dardik Alan
Published: December 2012

Reduced EphB4 expression is observed during vein graft adaptation and is associated with increased venous wall thickening. These findings suggest that EphB4 may mediate normal adult venous endothelial cell (EC) function and vein graft adaptation. We therefore tested the functional significance of EphB4 using EC with genetically reduced EphB4 signaling. EC were isolated from EphB4+/+ and EphB4+/− mice. In vitro function was assessed through EC proliferation, migration, nitric oxide (NO) synthesis, and chemokine production. A mouse vein graft model was used to correlate in vitro findings with in vivo vein grafts. Smooth muscle cells (SMC) were subjected to proliferation and migration assays using EphB4+/+ and EphB4+/− EC-conditioned medium. EphB4+/− EC exhibited diminished proliferation ( P < 0.0001, n = 6), migration ( P < 0.0001, n = 3), and NO production ( P = 0.0012, n = 3). EphB4+/− EC had increased VEGF-A mRNA ( P = 0.0006, n = 6) and protein ( P = 0.0106, n = 3) as well as increased secretion of VEGF-A ( P = 0.0010, n = 5), PDGF-BB ( P < 0.0001, n = 6), and TGF-β1 ( P < 0.0001, n = 6). EphB4+/−-conditioned medium promoted SMC proliferation ( P < 0.0001, n = 7) and migration ( P = 0.0358, n = 3). Vein grafts and EphB4+/− EC showed similarity with regard to VEGF-A and eNOS mRNA and protein expression. In conclusion, reduced venous EC EphB4 function is associated with a proangiogenic and mitogenic phenotype. EphB4+/− EC have increased secretion of SMC mitogens and reduced NO production that correlate with the thickened neointima formed during vein graft adaptation. These findings suggest that EphB4 remains active in adult venous EC and that loss of EphB4 plays a role in vein graft adaptation.
Acute exercise reverses starvation-mediated insulin resistance in humans
Authors: Frank Per , Katz Abram , Andersson Eva , Sahlin Kent
Published: December 2012

Within 2–3 days of starvation, pronounced insulin resistance develops, possibly mediated by increased lipid load. Here, we show that one exercise bout increases mitochondrial fatty acid (FA) oxidation and reverses starvation-induced insulin resistance. Nine healthy subjects underwent 75-h starvation on two occasions: with no exercise (NE) or with one exercise session at the end of the starvation period (EX). Muscle biopsies were analyzed for mitochondrial function, contents of glycogen, and phosphorylation of regulatory proteins. Glucose tolerance and insulin sensitivity, measured with an intravenous glucose tolerance test (IVGTT), were impaired after starvation, but in EX the response was attenuated or abolished. Glycogen stores were reduced, and plasma FA was increased in both conditions, with a more pronounced effect in EX. After starvation, mitochondrial respiration decreased with complex I substrate (NE and EX), but in EX there was an increased respiration with complex I + II substrate. EX altered regulatory proteins associated with increases in glucose disposal (decreased phosphorylation of glycogen synthase), glucose transport (increased phosphorylation of Akt substrate of 160 kDa), and FA oxidation (increased phosphorylation of acetyl-CoA carboxylase). In conclusion, exercise reversed starvation-induced insulin resistance and was accompanied by reduced glycogen stores, increased lipid oxidation capacity, and activation of signaling proteins involved in glucose transport and FA metabolism.
NKCC2A and NFAT5 regulate renal TNF production induced by hypertonic NaCl intake
Authors: Hao Shoujin , Bellner Lars , Ferreri Nicholas R.
Published: December 2012

Pathways that contribute to TNF production by the kidney are not well defined. Mice given 1% NaCl in the drinking water for 3 days exhibited a 2.5-fold increase in urinary, but not plasma, TNF levels compared with mice given tap water. Since furosemide attenuated the increase in TNF levels, we hypothesized that hypertonic NaCl intake increases renal TNF production by a pathway involving the Na+-K+-2Cl−cotransporter (NKCC2). A 2.5-fold increase in NKCC2A mRNA accumulation was observed in medullary thick ascending limb (mTAL) tubules from mice given 1% NaCl; a concomitant 2-fold increase in nuclear factor of activated T cells 5 (NFAT5) mRNA and protein expression was observed in the outer medulla. Urinary TNF levels were reduced in mice given 1% NaCl after an intrarenal injection of a lentivirus construct designed to specifically knockdown NKCC2A (EGFP-N2A-ex4); plasma levels of TNF did not change after injection of EGFP-N2A-ex4. Intrarenal injection of EGFP-N2A-ex4 also inhibited the increase of NFAT5 mRNA abundance in the outer medulla of mice given 1% NaCl. TNF production by primary cultures of mTAL cells increased approximately sixfold in response to an increase in osmolality to 400 mosmol/kgH2O produced with NaCl and was inhibited in cells transiently transfected with a dnNFAT5 construct. Transduction of cells with EGFP-N2A-ex4 also prevented increases in TNF mRNA and protein production in response to high NaCl concentration and reduced transcriptional activity of a NFAT5 promoter construct. Since NKCC2A expression is restricted to the TAL, NKCC2A-dependent activation of NFAT5 is part of a pathway by which the TAL produces TNF in response to hypertonic NaCl intake.
A potential role for caveolin-1 in VEGF-induced fibronectin upregulation in mesangial cells: involvement of VEGFR2 and Src
Authors: Wu Tingting , Zhang Baifang , Ye Feng , Xiao Zeling
Published: December 2012

VEGF is known to be an endothelial cell mitogen that stimulates angiogenesis by promoting endothelial cell survival, proliferation, migration, and differentiation. Recent studies have suggested that VEGF may play a pivotal role in glomerular sclerosis through extracellular matrix protein (ECM) accumulation, although the signaling mechanism is still unclear. The GTPase RhoA has been implicated in VEGF-induced type IV collagen accumulation in some settings. Here we study the role of different VEGF receptors and membrane microdomain caveolae in VEGF-induced RhoA activation and fibronectin upregulation in mesangial cells (MCs). In primary rat MC, VEGF time and dose dependently increased fibronectin production. Rho pathway inhibition blocked VEGF-induced fibronectin upregulation. VEGF-induced RhoA activation was prevented by disrupting caveolae with cholesterol depletion and rescued by cholesterol repletion. VEGF stimulation led to a markedly increased VEGFR2/caveolin-1 but failed to increase VEGFR1/caveolin-1 association. VEGF also increased caveolin-1/Src association and activated Src, and Src inhibitor blocked RhoA activation and fibronectin upregulation. Src-mediated phosphorylation of caveolin-1 on Y14 has also been implicated in signaling responses. Overexpression of nonphosphorylatable caveolin-1 Y14A prevented VEGF-induced RhoA activation and fibronectin upregulation. In vivo, although VEGFR1 and VEGFR2 protein levels were both increased in the kidney cortices of diabetic rats, VEGFR2/caveolin-1 association but not VEGFR1/caveolin-1 association was significantly increased. In conclusion, VEGF-induced RhoA activation and fibronectin upregulation require caveolae and caveolin-1 interaction with VEGFR2 and Src. Interference with caveolin/-ae signaling may provide new avenues for the treatment of fibrotic renal disease.
Altered V-ATPase expression in renal intercalated cells isolated from B1 subunit-deficient mice by fluorescence-activated cell sorting
Authors: Vedovelli Luca , Rothermel John T. , Finberg Karin E. , Wagner Carsten A. , Azroyan Anie , Hill Eric , Breton Sylvie , Brown Dennis , Păunescu Teodor G.
Published: December 2012

Unlike human patients with mutations in the 56-kDa B1 subunit isoform of the vacuolar proton-pumping ATPase (V-ATPase), B1-deficient mice (Atp6v1b1−/−) do not develop metabolic acidosis under baseline conditions. This is due to the insertion of V-ATPases containing the alternative B2 subunit isoform into the apical membrane of renal medullary collecting duct intercalated cells (ICs). We previously reported that quantitative Western blots (WBs) from whole kidneys showed similar B2 protein levels in Atp6v1b1−/−and wild-type mice (Păunescu TG, Russo LM, Da Silva N, Kovacikova J, Mohebbi N, Van Hoek AN, McKee M, Wagner CA, Breton S, Brown D. Am J Physiol Renal Physiol 293: F1915–F1926, 2007). However, WBs from renal medulla (including outer and inner medulla) membrane and cytosol fractions reveal a decrease in the levels of the ubiquitous V-ATPase E1 subunit. To compare V-ATPase expression specifically in ICs from wild-type and Atp6v1b1−/−mice, we crossed mice in which EGFP expression is driven by the B1 subunit promoter (EGFP-B1+/+mice) with Atp6v1b1−/−mice to generate novel EGFP-B1−/−mice. We isolated pure IC populations by fluorescence-assisted cell sorting from EGFP-B1+/+and EGFP-B1−/−mice to compare their V-ATPase subunit protein levels. We report that V-ATPase A, E1, and H subunits are all significantly downregulated in EGFP-B1−/−mice, while the B2 protein level is considerably increased in these animals. We conclude that under baseline conditions B2 upregulation compensates for the lack of B1 and is sufficient to maintain basal acid-base homeostasis, even when other V-ATPase subunits are downregulated.
Role of the SNARE protein SNAP23 on cAMP-stimulated renin release in mouse juxtaglomerular cells
Authors: Mendez Mariela , Gaisano Herbert Y.
Published: December 2012

Renin, the rate-limiting enzyme in the formation of angiotensin II, is synthesized and stored in granules in juxtaglomerular (JG) cells. Therefore, the controlled mechanism involved in renin release is essential for the regulation of blood pressure. Exocytosis of renin-containing granules is likely involved in renin release; a process stimulated by cAMP. We found that the “soluble NSF ( N-ethylmaleimide-sensitive factor) attachment protein receptor” (SNARE) protein VAMP2 mediates cAMP-stimulated renin release and exocytosis in JG cells. To mediate exocytosis, VAMP2 must interact with a synaptosome-associated protein (SNAP). In the renal cortex, the isoform SNAP23 is abundantly expressed. We hypothesized that SNAP23 mediates cAMP-stimulated renin release from primary cultures of mouse JG cells. We found that SNAP23 protein is expressed and colocalized with renin-containing granules in primary cultures of mouse JG cell lysates. Thus, we then tested the involvement of SNAP23 in cAMP-stimulated renin release by transducing JG cells with a dominant-negative SNAP23 construct. In control JG cells transduced with a scrambled sequence, increasing cAMP stimulated renin release from 1.3 ± 0.3 to 5.3 ± 1.2% of renin content. In cells transduced with dominant-negative SNAP23, cAMP increased renin from 1.0 ± 0.1 to 3.0 ± 0.6% of renin content, a 50% blockade. Botulinum toxin E, which cleaves and inactivates SNAP23, reduced cAMP-stimulated renin release by 42 ± 17%. Finally, adenovirus-mediated silencing of SNAP23 significantly blocked cAMP-stimulated renin release by 50 ± 13%. We concluded that the SNARE protein SNAP23 mediates cAMP-stimulated renin release. These data show that renin release is a SNARE-dependent process.
Spontaneous and evoked contractions are regulated by PKC-mediated signaling in detrusor smooth muscle: involvement of BK channels
Authors: Hypolite Joseph A. , Lei Qi , Chang Shaohua , Zderic Stephen A. , Butler Stephan , Wein Alan J. , Malykhina Anna P. , Chacko Samuel
Published: December 2012

Protein kinase C (PKC) and large conductance Ca2+-activated potassium channels (BK) are downregulated in the detrusor smooth muscle (DSM) in partial bladder outlet obstruction (PBOO). DSM from these bladders display increased spontaneous activity. This study examines the involvement of PKC in the regulation of spontaneous and evoked DSM contractions and whether pharmacologic inhibition of PKC in normal DSM contributes to increased detrusor excitability. Results indicate the PKC inhibitor bisindolylmaleimide 1 (Bim-1) prevented a decline in the amplitude of spontaneous DSM contractions over time in vitro, and these contractions persist in the presence of tetrodotoxin. Bim-1 also reduced the basal DSM tone, and the ability to maintain force in response to electrical field stimulation, but did not affect maximum contraction. The PKC activator phorbol-12,13-dibutyrate (PDBu) significantly reduced the amplitude and increased the frequency of spontaneous contractions at low concentrations (10 nM), while causing an increase in force at higher concentrations (1 μM). Preincubation of DSM strips with iberiotoxin prevented the inhibition of spontaneous contractions by PDBu. The BK channel openers isopimaric acid and NS1619 reduced the Bim-1-induced enhancement of spontaneous contractions in DSM strips. Our data suggest that PKC has a biphasic activation profile in the DSM and that it may play an important role in maintaining the quiescent state of the normal bladder during storage through the effects on BK channel, while helping to maintain force required for bladder emptying. The data also suggest that PKC dysfunction, as seen in PBOO, contributes to detrusor overactivity.
Elevated cJUN expression and an ATF/CRE site within the ATF3 promoter contribute to activation of ATF3 transcription by the amino acid response
Authors: Fu Lingchen , Kilberg Michael S.
Published: December 2012

Mammalian cells respond to amino acid deprivation through multiple signaling pathways referred to as the amino acid response (AAR). Transcription factors mediate the AAR after their activation by several mechanisms; examples include translational control (activating transcription factor 4, ATF4), phosphorylation (p-cJUN), and transcriptional control (ATF3). ATF4 induces ATF3 transcription through a promoter-localized C/EBP-ATF response element (CARE). The present report characterizes an ATF/CRE site upstream of the CARE that also contributes to AAR-induced ATF3 transcription. ATF4 binds to the ATF/CRE and CARE sequences and both are required for a maximal response to ATF4 induction. ATF3, which antagonizes ATF4 and represses its own gene, also exhibited binding activity to the ATF/CRE and CARE sequences. The AAR resulted in elevated total cJUN and p-cJUN protein levels and both forms exhibited binding activity to the ATF/CRE and CARE ATF3 sequences. Knockdown of AAR-enhanced cJUN expression blocked induction of the ATF3 gene and mutation of either the ATF/CRE or the CARE site prevented the cJUN-dependent increase in ATF3-driven luciferase activity. The results indicate that both increased cJUN and the cis-acting ATF/CRE sequence within the ATF3 promoter contribute to the transcriptional activation of the gene during the AAR.
The Generalization of the Poisson Sum Formula Associated with the Linear Canonical Transform
Authors: Zhang Jun-Fang , Hou Shou-Ping
Published: December 2012

The generalization of the classical Poisson sum formula, by replacing the ordinary Fourier transform by the canonical transformation, has been derived in the linear canonical transform sense. Firstly, a new sum formula of Chirp‐periodic property has been introduced, and then the relationship between this new sum and the original signal is derived. Secondly, the generalization of the classical Poisson sum formula to the linear canonical transform sense has been obtained.
Association betweenBDNFrs6265 and Obesity in the Boston Puerto Rican Health Study
Authors: Ma Xian-Yong , Qiu Wei Qiao , Smith Caren E. , Parnell Laurence D. , Jiang Zong-Yong , Ordovas Jose M. , Tucker Katherine L. , Lai Chao-Qiang
Published: December 2012

Brain-derived neurotrophic factor (BDNF) has been associated with regulation of body weight and appetite. The goal of this study was to examine the interactions of a functional variant (rs6265) in theBDNFgene with dietary intake for obesity traits in the Boston Puerto Rican Health Study.BDNFrs6265 was genotyped in 1147 Puerto Rican adults and examined for association with obesity-related traits. Men (n=242) with the GG genotype had higher BMI (P=0.009), waist circumference (P=0.002), hip (P=0.002), and weight (P=0.03) than GA or AA carriers (n=94). They had twice the risk of being overweight (BMI≥25) relative to GA or AA carriers (OR = 2.08, CI = 1.02–4.23, andP=0.043). Interactions between rs6265 and polyunsaturated fatty acids (PUFA) intake were associated with BMI, hip, and weight, and n-3 : n-6 PUFA ratio with waist circumference in men. In contrast, women (n=595) with the GG genotype had significantly lower BMI (P=0.009), hip (P=0.029), and weight (P=0.027) than GA or AA carriers (n=216). Women with the GG genotype were 50% less likely to be overweight compared to GA or AA carriers (OR = 0.05, CI = 0.27–0.91, andP=0.024). In summary,BDNFrs6265 is differentially associated with obesity risk by sex and interacts with PUFA intake influencing obesity traits in Boston Puerto Rican men.
New Nonsmooth Equations‐Based Algorithms for ℓ1‐Norm Minimization and Applications
Authors: Wu Lei , Sun Zhe
Published: December 2012

Recently, Xiao et al. proposed a nonsmooth equations‐based method to solve the ℓ1‐norm minimization problem (2011). The advantage of this method is its simplicity and lower storage. In this paper, based on new nonsmooth equations reformulation, we investigate new nonsmooth equations‐based algorithms for solving ℓ1‐norm minimization problems. Under mild conditions, we show that the proposed algorithms are globally convergent. The preliminary numerical results demonstrate the effectiveness of the proposed algorithms.
Cedecea davisae’s Role in a Polymicrobial Lung Infection in a Cystic Fibrosis Patient
Authors: Ismaael Thayer G. , Zamora Eleana M. , Khasawneh Faisal A.
Published: December 2012

Chronic airway colonization and infection are the hallmark of cystic fibrosis (CF).Staphylococcus aureus, Pseudomonas aeruginosa, andBurkholderia cepaciaare well-documented bacterial culprits in this chronic suppurative airway disease. Advanced molecular diagnostics have uncovered a possible role of a larger group of microorganisms in CF.Cedeceais a member of the family Enterobacteriaceae and is an emerging pathogen. We present a case of a polymicrobial healthcare-associated pneumonia in a CF patient caused byCedecea davisae, among other bacteria.
Numerical Study for Blood Flow in Pulmonary Arteries after Repair of Tetralogy of Fallot
Authors: Chern Ming-Jyh , Wu Ming-Ting , Her Sheau-Wei
Published: December 2012

Pulmonary regurgitation (PR) is a common phenomenon in pulmonary arteries in patients after repair of tetralogy of Fallot (TOF). The regurgitation fraction of left pulmonary artery (LPA) is usually greater than right pulmonary artery (RPA) according to clinic data. It may be related to blood flow in pulmonary arteries. Therefore, understanding hemodynamics in pulmonary arteries helps to comprehend the reason. The aim of this study is to use 3D reconstructed pulmonary artery models from magnetic resonance imaging (MRI) and to use numerical approaches for simulation of flow variations in pulmonary arteries after repair of TOF. From the numerical results, the blood flow is influenced by the bifurcation angles and geometry of pulmonary artery. The regurgitation happens first in LPA after repair of TOF due to the small angle between LPA and main pulmonary artery (MPA). The recirculation region which obstructs forward blood flow to the left lung is found in LPA during acceleration of systole. We also analyze the pressure distribution; the extreme pressure variations are in dilation area of MPA. Numerical data including regurgitation in MPA, LPA, and RPA are compared with phase contrast MR measured data. Good agreements are found between numerical results and measured data.
Incidental Renal Botryomycosis in a Nonfunctioning Kidney
Authors: Mathew Mary , Nayal Bhavna , Nagel Bhawna , Thomas Joseph
Published: December 2012

Botryomycosis is a unique form of bacterial infection, closely mimicking actinomycosis. The usual site of occurrence is the skin and renal botryomycosis is very rare. The most common organism isStaphylococcus aureuswhich can be identified using Gram stain and confirmed by culture. Early and accurate diagnosis can ensure appropriate antibiotic therapy. We present a young lady diagnosed to have incidental botryomycosis of the kidney, following nephrectomy.
Analysis of the Error in a Numerical Method Used to Solve Nonlinear Mixed Fredholm-Volterra-Hammerstein Integral Equations
Authors: Gámez D.
Published: December 2012

This work presents an analysis of the error that is committed upon having obtained the approximate solution of the nonlinear Fredholm-Volterra-Hammerstein integral equation by means of a method for its numerical resolution. The main tools used in the study of the error are the properties of Schauder bases in a Banach space.
Empirical Likelihood Estimation for Population Pharmacokinetic Study Based on Generalized Linear Model
Authors: Yan Fang-rong , Lin Jin-guan , Huang Yuan , Liu Jun-lin , Lu Tao
Published: December 2012

To obtain efficient estimation of parameters is a major objective in population pharmacokinetic study. In this paper, we propose an empirical likelihood‐based method to analyze the population pharmacokinetic data based on the generalized linear model. A nonparametric version of the Wilk′s theorem for the limiting distributions of the empirical likelihood ratio is derived. Simulations are conducted to demonstrate the accuracy and efficiency of empirical likelihood method. An application illustrating our methods and supporting the simulation study results is presented. The results suggest that the proposed method is feasible for population pharmacokinetic data.
Successive Matrix Squaring Algorithm for Computing the Generalized Inverse AT,S(2)
Authors: Liu Xiaoji , Qin Yonghui
Published: December 2012

We investigate successive matrix squaring (SMS) algorithms for
computing the generalized inverse of a given matrix A ∈ Cm×n.
Status and New Data of the Geochemical Determination of the pp-Neutrino Flux by LOREX
Authors: Pavićević M. K. , Bosch F. , Amthauer G. , Aničin I. , Boev B. , Brüchle W. , Cvetković V. , Djurčić Z. , Henning W. F. , Jelenković R. , Pejović V. , Weiss A.
Published: December 2012

LOREX (LORandite EXperiment) addresses the determination of the solar (pp) neutrino flux during the last four million years by exploiting the reaction 205Tl+νe→ 205Pb+e-with an incomparably low-energy threshold of 50 keV for the capture of solar neutrinos. The ratio of205Pb/205Tl atoms in the Tl-bearing mineral lorandite provides, if corrected for the cosmic-ray induced background, the product of the flux of solar neutrinos and their capture probability by205Tl, averaged over the age of lorandite. To get the mean solar neutrino flux itself, four problems have to be addressed: (1) the geological age of lorandite, (2) the amount of background cosmic-ray-induced205Pb atoms which strongly depends on the erosion rate of the lorandite-bearing rocks, (3) the capture probability of solar neutrinos by205Tl and (4) the extraction of lorandite and the appropriate technique to “count” the small number of205Pb atoms in relation to the number of205Tl atoms. This paper summarizes the status of items 1 (age) and 3 (neutrino capture probability) and presents in detail the progress achieved most recently concerning the items 2 (background/erosion) and 4 (“counting” of205Pb atoms in lorandite).
Van der Woude Syndrome Associated with Hypodontia: A Rare Clinical Entity
Authors: Soni Romesh , Vivek Rajul , Srivastava Adit , Singh Ankita , Srivastava Shalabh , Chaturvedi T. P.
Published: December 2012

Van der Woude syndrome (VWS) is usually underreported and frequently not diagnosed. The phenomenon that cleft lip and palate are regularly combined in the same pedigree makes it unique. A meticulous examination of a patient with lip pits may reveal a hidden form of a cleft, for example, submucous. This paper presents a case of VWS in a ten-year-old boy with characteristic orofacial features. Special emphasis has also been given on the need for appropriate genetic counseling.
Optimal Bounds for Neuman‐Sándor Mean in Terms of the Convex Combinations of Harmonic, Geometric, Quadratic, and Contraharmonic Means
Authors: Zhao Tie-Hong , Chu Yu-Ming , Liu Bao-Yu
Published: December 2012

We present the best possible lower and upper bounds for the Neuman‐Sándor mean in terms of the convex combinations of either the harmonic and quadratic means or the geometric and quadratic means or the harmonic and contraharmonic means.