bluuebunny/crossref_metadata_2025 huggingface dataset:
Mg2+Deprivation Elicits Rapid Ca2+Uptake and Activates Ca2+/Calcineurin Signaling inSaccharomyces cerevisiae
Authors: Wiesenberger Gerlinde , Steinleitner Katarina , Malli Roland , Graier Wolfgang F. , Vormann Jürgen , Schweyen Rudolf J. , Stadler Jochen A.
Published: March 2007

To learn about the cellular processes involved in Mg2+homeostasis and the mechanisms allowing cells to cope with low Mg2+availability, we performed RNA expression-profiling experiments and followed changes in gene activity upon Mg2+depletion on a genome-wide scale. A striking portion of genes up-regulated under Mg2+depletion are also induced by high Ca2+and/or alkalinization. Among the genes significantly up-regulated by Mg2+starvation, Ca2+stress, and alkalinization areENA1(encoding a P-type ATPase sodium pump) andPHO89(encoding a sodium/phosphate cotransporter). We show that up-regulation of these genes is dependent on the calcineurin/Crz1p (calcineurin-responsive zinc finger protein) signaling pathway. Similarly to Ca2+stress, Mg2+starvation induces translocation of the transcription factor Crz1p from the cytoplasm into the nucleus. The up-regulation ofENA1andPHO89upon Mg2+starvation depends on extracellular Ca2+. Using fluorescence resonance energy transfer microscopy, we demonstrate that removal of Mg2+results in an immediate increase in free cytoplasmic Ca2+. This effect is dependent on external Ca2+. The results presented indicate that Mg2+depletion in yeast cells leads to enhanced cellular Ca2+concentrations, which activate the Crz1p/calcineurin pathway. We provide evidence that calcineurin/Crz1p signaling is crucial for yeast cells to cope with Mg2+depletion stress.
Parallel β-Helix Proteins Required for Accurate Capsule Polysaccharide Synthesis and Virulence in the Yeast
Cryptococcus neoformans
Authors: Liu Oliver W. , Kelly Mark J. S. , Chow Eric D. , Madhani Hiten D.
Published: March 2007

The principal capsular polysaccharide of the opportunistic fungal pathogen
Cryptococcus neoformans
consists of an α-1,3-linked mannose backbone decorated with a repeating pattern of glucuronyl and xylosyl side groups. This structure is critical for virulence, yet little is known about how the polymer, called glucuronoxylomannan (GXM), is faithfully synthesized and assembled. We have generated deletions in two genes encoding predicted parallel β-helix repeat proteins, which we have designated
PBX1
and
PBX2
. Deletion of either gene results in a dry-colony morphology, clumpy cells, and decreased capsule integrity. Two-dimensional nuclear magnetic resonance spectroscopy of purified GXM from the mutants indicated that both the wild-type GXM structure and novel, aberrant linkages were present. Carbohydrate composition and linkage analysis determined that these aberrant structures are correlated with the incorporation of terminal glucose residues that are not found in wild-type capsule polysaccharide. We conclude that Pbx1 and Pbx2 are required for the fidelity of GXM synthesis and may be involved in editing incorrectly added glucose residues.
PBX1
and
PBX2
knockout mutants showed severely attenuated virulence in a murine inhalation model of cryptococcosis. Unlike acapsular strains, these mutant strains induced delayed symptoms of cryptococcosis, though the infected animals eventually contained the infection and recovered.
A-Factor and Phosphate Depletion Signals Are Transmitted to the Grixazone Biosynthesis Genes via the Pathway-Specific Transcriptional Activator GriR
Authors: Higashi Tatsuichiro , Iwasaki Yuko , Ohnishi Yasuo , Horinouchi Sueharu
Published: March 2007

Grixazone (GX), which is a diffusible yellow pigment containing a phenoxazinone chromophore, is one of the secondary metabolites under the control of A-factor (2-isocapryloyl-3
R
-hydroxymethyl-γ-butyrolactone) in
Streptomyces griseus
. GX production is also induced by phosphate starvation. The whole biosynthesis gene cluster for GX was cloned and characterized. The gene cluster consisting of 13 genes contained six transcriptional units,
griT
,
griSR
,
griR
,
griAB
,
griCDEFG
, and
griJIH
. During cultivation in a phosphate-depleted medium, the six promoters were activated in the order (i)
griR
, (ii)
griC
and
griJ
, and (iii)
griT
,
griS
, and
griA
. Disruption of
griR
, which encodes a SARP family transcriptional regulator, abolished the transcriptional activation of all other genes in the cluster. In addition, ectopic expression of
griR
from a constitutively active promoter resulted in GX overproduction even in the absence of AdpA, a key transcriptional activator in the A-factor regulatory cascade, and in the presence of phosphate at a high concentration. GriR monomers bound direct repeat sequences in the
griC
and
griJ
promoters in a cooperative manner. Therefore, the early active genes (
griCDEFG
and
griJIH
), all of which, except for
griG
(which encodes a transporter-like protein), encode the GX biosynthesis enzymes, were directly activated by GriR. The transcription of
griR
was greatly reduced in the presence of phosphate at a high concentration and was hardly detected in the absence of AdpA. These findings showed that both A-factor and phosphate depletion signals were required for
griR
transcription and both signals were transmitted to the GX biosynthesis genes solely via the
griR
promoter.
Complete Nucleotide Sequence of the 113-Kilobase Linear Catabolic Plasmid pAL1 of
Arthrobacter nitroguajacolicus
Rü61a and Transcriptional Analysis of Genes Involved in Quinaldine Degradation
Authors: Parschat Katja , Overhage Jörg , Strittmatter Axel W. , Henne Anke , Gottschalk Gerhard , Fetzner Susanne
Published: March 2007

The nucleotide sequence of the linear catabolic plasmid pAL1 from the 2-methylquinoline (quinaldine)-degrading strain
Arthrobacter nitroguajacolicus
Rü61a comprises 112,992 bp. A total of 103 open reading frames (ORFs) were identified on pAL1, 49 of which had no annotatable function. The ORFs were assigned to the following functional groups: (i) catabolism of quinaldine and anthranilate, (ii) conjugation, and (iii) plasmid maintenance and DNA replication and repair. The genes for conversion of quinaldine to anthranilate are organized in two operons that include ORFs presumed to code for proteins involved in assembly of the quinaldine-4-oxidase holoenzyme, namely, a MobA-like putative molybdopterin cytosine dinucleotide synthase and an XdhC-like protein that could be required for insertion of the molybdenum cofactor. Genes possibly coding for enzymes involved in anthranilate degradation via 2-aminobenzoyl coenzyme A form another operon. These operons were expressed when cells were grown on quinaldine or on aromatic compounds downstream in the catabolic pathway. Single-stranded 3′ overhangs of putative replication intermediates of pAL1 were predicted to form elaborate secondary structures due to palindromic and superpalindromic terminal sequences; however, the two telomeres appear to form different structures. Sequence analysis of ORFs 101 to 103 suggested that pAL1 codes for one or two putative terminal proteins, presumed to be covalently bound to the 5′ termini, and a multidomain telomere-associated protein (Tap) comprising 1,707 amino acids. Even if the putative proteins encoded by ORFs 101 to 103 share motifs with the Tap and terminal proteins involved in telomere patching of
Streptomyces
linear replicons, their overall sequences and domain structures differ significantly.
Identification of NovelEscherichia coliRibosome-Associated Proteins Using Isobaric Tags and Multidimensional Protein Identification Techniques
Authors: Jiang M. , Sullivan S. M. , Walker A. K. , Strahler J. R. , Andrews P. C. , Maddock J. R.
Published: March 2007

Biogenesis of the large ribosomal subunit requires the coordinate assembly of two rRNAs and 33 ribosomal proteins. In vivo, additional ribosome assembly factors, such as helicases, GTPases, pseudouridine synthetases, and methyltransferases, are also critical for ribosome assembly. To identify novel ribosome-associated proteins, we used a proteomic approach (isotope tagging for relative and absolute quantitation) that allows for semiquantitation of proteins from complex protein mixtures. Ribosomal subunits were separated by sucrose density centrifugation, and the relevant fractions were pooled and analyzed. The utility and reproducibility of the technique were validated via a double duplex labeling method. Next, we examined proteins from 30S, 50S, and translating ribosomes isolated at both 16°C and 37°C. We show that the use of isobaric tags to quantify proteins from these particles is an excellent predictor of the particles with which the proteins associate. Moreover, in addition to bona fide ribosomal proteins, additional proteins that comigrated with different ribosomal particles were detected, including both known ribosomal assembly factors and unknown proteins. The ribosome association of several of these proteins, as well as others predicted to be associated with ribosomes, was verified by immunoblotting. Curiously, deletion mutants for the majority of these ribosome-associated proteins had little effect on cell growth or on the polyribosome profiles.
A Putative Gene Cluster for Aminoarabinose Biosynthesis Is Essential for
Burkholderia cenocepacia
Viability
Authors: Ortega Ximena P. , Cardona Silvia T. , Brown Alan R. , Loutet Slade A. , Flannagan Ronald S. , Campopiano Dominic J. , Govan John R. W. , Valvano Miguel A.
Published: March 2007

Using a conditional mutagenesis strategy we demonstrate here that a gene cluster encoding putative aminoarabinose (Ara4N) biosynthesis enzymes is essential for the viability of
Burkholderia cenocepacia
. Loss of viability is associated with dramatic changes in bacterial cell morphology and ultrastructure, increased permeability to propidium iodide, and sensitivity to sodium dodecyl sulfate, suggesting a general cell envelope defect caused by the lack of Ara4N.
Two Distinct Pathways Supply Anthranilate as a Precursor of thePseudomonasQuinolone Signal
Authors: Farrow John M. , Pesci Everett C.
Published: March 2007

Pseudomonas aeruginosais an opportunistic pathogen that causes serious infections in immunocompromised patients and those with cystic fibrosis (CF). This gram-negative bacterium uses multiple cell-to-cell signals to control numerous cellular functions and virulence. One of these signals is 2-heptyl-3-hydroxy-4-quinolone, which is referred to as thePseudomonasquinolone signal (PQS). This signal functions as a coinducer for a transcriptional regulator (PqsR) to positively control multiple virulence genes and its own synthesis. PQS production is required for virulence in multiple models of infection, and it has been shown to be produced in the lungs of CF patients infected byP. aeruginosa. One of the precursor compounds from which PQS is synthesized is the metabolite anthranilate. This compound can be derived from the conversion of chorismate to anthranilate by an anthranilate synthase or through the degradation of tryptophan via the anthranilate branch of the kynurenine pathway. In this study, we present data which help to define the kynurenine pathway inP. aeruginosaand show that the kynurenine pathway serves as a critical source of anthranilate for PQS synthesis. We also show that thekynpathway genes are induced during growth with tryptophan and that they are autoregulated by kynurenine. This study provides solid foundations for the understanding of howP. aeruginosaproduces the anthranilate that serves as a precursor to PQS and other 4-quinolones.
Transcription Termination within the Iron Transport-Biosynthesis Operon ofVibrio anguillarumRequires an Antisense RNA
Authors: Stork Michiel , Di Lorenzo Manuela , Welch Timothy J. , Crosa Jorge H.
Published: March 2007

The iron transport-biosynthesis (ITB) operon inVibrio anguillarumincludes four genes for ferric siderophore transport,fatD, -C, -B, and -A, and two genes for siderophore biosynthesis,angRandangT. This cluster plays an important role in the virulence mechanisms of this bacterium. Despite being part of the same polycistronic mRNA, the relative levels of transcription for thefatportion and for the whole ITB message differ profoundly, the levels of thefattranscript being about 17-fold higher. Using S1 nuclease mapping,lacZtranscriptional fusions, and in vitro studies, we were able to show that the differential gene expression within the ITB operon is due to termination of transcription between thefatAandangRgenes, although a few transcripts proceeded beyond the termination site to the end of this operon. This termination process requires a 427-nucleotide antisense RNA that spans the intergenic region and acts as a novel transcriptional terminator.
Inverse Regulation of Biofilm Formation and Swarming Motility byPseudomonas aeruginosaPA14
Authors: Caiazza Nicky C. , Merritt Judith H. , Brothers Kimberly M. , O'Toole George A.
Published: March 2007

We previously reported that SadB, a protein of unknown function, is required for an early step in biofilm formation by the opportunistic pathogenPseudomonas aeruginosa. Here we report that a mutation insadBalso results in increased swarming compared to the wild-type strain. Our data are consistent with a model in which SadB inversely regulates biofilm formation and swarming motility via its ability both to modulate flagellar reversals in a viscosity-dependent fashion and to influence the production of the Pel exopolysaccharide. We also show that SadB is required to properly modulate flagellar reversal rates via chemotaxis cluster IV (CheIV cluster). Mutational analyses of two components of the CheIV cluster, the methyl-accepting chemotaxis protein PilJ and the PilJ demethylase ChpB, support a model wherein this chemotaxis cluster participates in the inverse regulation of biofilm formation and swarming motility. Epistasis analysis indicates that SadB functions upstream of the CheIV cluster. We propose thatP. aeruginosautilizes a SadB-dependent, chemotaxis-like regulatory pathway to inversely regulate two key surface behaviors, biofilm formation and swarming motility.
Regulation of Actin Filament Assembly by Arp2/3 Complex and Formins
Authors: Pollard Thomas D.
Published: March 2007

This review summarizes what is known about the biochemical and biophysical mechanisms that initiate the assembly of actin filaments in cells. Assembly and disassembly of these filaments contribute to many types of cellular movements. Numerous proteins regulate actin assembly, but Arp2/3 complex and formins are the focus of this review because more is known about them than other proteins that stimulate the formation of new filaments. Arp2/3 complex is active at the leading edge of motile cells, where it produces branches on the sides of existing filaments. Growth of these filaments produces force to protrude the membrane. Crystal structures, reconstructions from electron micrographs, and biophysical experiments have started to map out the steps through which proteins called nucleation-promoting factors stimulate the formation of branches. Formins nucleate and support the elongation of unbranched actin filaments for cytokinesis and various types of actin filament bundles. Formins associate processively with the fast-growing ends of filaments and protect them from capping.
Conformational Dynamics and Ensembles in Protein Folding
Authors: Muñoz Victor
Published: March 2007

Recent experimental developments are changing the ways we interpret experimental data in protein folding, leading to a closer connection with theory and an improved understanding of some long-standing questions in the field. We now have a basic roadmap of the types of polypeptide motions and timescales that are relevant to the various folding stages. The folding barriers estimated with a variety of independent methods are consistently small, indicating that several fast-folding proteins are near or within the downhill folding regime. Finally, the structural and statistical analysis of global downhill folding is promising to open a new avenue of research in which folding mechanisms and the networks of noncovalent interactions that stabilize native structures are directly resolved in equilibrium experiments of nonmutated proteins.
Mechanism of DNA Transport Through Pores
Authors: Muthukumar Murugappan
Published: March 2007

The transport of electrically charged macromolecules such as DNA through narrow pores is a fundamental process in life. When polymer molecules are forced to navigate through pores, their transport is controlled by entropic barriers that accompany their conformational changes. During the past decade, exciting results have emerged from single-molecule electrophysiology experiments. Specifically, the passage of single-stranded DNA/RNA through alpha-hemolysin pores and double-stranded DNA through solid-state nanopores has been investigated. By a combination of these results with the entropic barrier theory of polymer transport and macromolecular simulations, an understanding of the mechanism of DNA transport through pores has emerged.
Microfluidic Large-Scale Integration: The Evolution of Design Rules for Biological Automation
Authors: Melin Jessica , Quake Stephen R.
Published: March 2007

Microfluidic large-scale integration (mLSI) refers to the development of microfluidic chips with thousands of integrated micromechanical valves and control components. This technology is utilized in many areas of biology and chemistry and is a candidate to replace today's conventional automation paradigm, which consists of fluid-handling robots. We review the basic development of mLSI and then discuss design principles of mLSI to assess the capabilities and limitations of the current state of the art and to facilitate the application of mLSI to areas of biology. Many design and practical issues, including economies of scale, parallelization strategies, multiplexing, and multistep biochemical processing, are discussed. Several microfluidic components used as building blocks to create effective, complex, and highly integrated microfluidic networks are also highlighted.
Caveolin-1 and caveolin-3 regulate Ca2+homeostasis of single smooth muscle cells from rat cerebral resistance arteries
Authors: Kamishima T. , Burdyga T. , Gallagher J. A. , Quayle J. M.
Published: March 2007

The role of caveolins, signature proteins of caveolae, in arterial Ca2+regulation is unknown. We investigated modulation of Ca2+homeostasis by caveolin-1 and caveolin-3 using smooth muscle cells from rat cerebral resistance arteries. Membrane current and Ca2+transients were simultaneously measured with voltage-clamped single cells. Membrane depolarization triggered Ca2+current and increased intracellular Ca2+concentration ([Ca2+]i). After repolarization, elevated [Ca2+]ireturned to the resting level. Ca2+removal rate was determined from the declining phase of the Ca2+transient. Application of caveolin-1 antibody or caveolin-1 scaffolding domain peptide, corresponding to amino acid residues 82–101 of caveolin-1, significantly slowed Ca2+removal rate at a measured [Ca2+]iof 250 nM, with little effect at a measured [Ca2+]iof 600 nM. Application of caveolin-3 antibody or caveolin-3 scaffolding domain peptide, corresponding to amino acid residues 55–74 of caveolin-3, also significantly slowed Ca2+removal rate at a measured [Ca2+]iof 250 nM, with little effect at a measured [Ca2+]iof 600 nM. Likewise, application of calmodulin inhibitory peptide, autocamtide-2-related inhibitory peptide, and cyclosporine A, inhibitors for calmodulin, Ca2+/calmodulin-dependent protein kinase II, and calcineurin, also significantly inhibited Ca2+removal rate at a measured [Ca2+]iof 250 nM but not at 600 nM. Application of cyclopiazonic acid, a sarcoplasmic reticulum Ca2+ATPase inhibitor, also significantly inhibited Ca2+removal rate at a measured [Ca2+]iof 250 nM but not at 600 nM. Our results suggest that caveolin-1 and caveolin-3 are important in Ca2+removal of resistance artery smooth muscle cells.
Dual cardiac contractile effects of the α2-AMPK deletion in low-flow ischemia and reperfusion
Authors: Carvajal Karla , Zarrinpashneh Elham , Szarszoi Ondrej , Joubert Frederic , Athea Yoni , Mateo Philippe , Gillet Brigitte , Vaulont Sophie , Viollet Benoit , Bigard Xavier , Bertrand Luc , Ventura-Clapier Renée , Hoerter Jacqueline A.
Published: March 2007

Because the question “is AMP-activated protein kinase (AMPK) α2-isoform a friend or a foe in the protection of the myocardium against ischemia-reperfusion injury?” is still in debate, we studied the functional consequence of its deletion on the contractility, the energetics, and the respiration of the isolated perfused heart and characterized the response to low-flow ischemia and reperfusion with glucose and pyruvate as substrates. α2-AMPK deletion did not affect basal contractility, respiration, and high-energy phosphate contents but induced a twofold reduction in glycogen content and a threefold reduction in glucose uptake. Low-flow ischemia increased AMPK phosphorylation and stimulated glucose uptake and phosphorylation in both α2-knockout (α2-KO) and wild-type (WT) groups. The high sensitivity of α2-KO to the development of ischemic contracture was attributed to the constitutive impairment in glucose transport and glycogen content and not to a perturbation of the energy transfer by creatine kinase (CK). The functional coupling of MM-CK to myofibrillar ATPase and the CK fluxes were indeed similar in α2-KO and WT. Low-flow ischemia impaired CK flux by 50% in both strains, showing that α2-AMPK does not control CK activity. Despite the higher sensitivity to contracture, the postischemic contractility recovered to similar levels in both α2-KO and WT in the absence of fatty acids. In their presence, α2-AMPK deletion also accelerated the contracture but delayed postischemic contractile recovery. In conclusion, α2-AMPK is required for a normal glucose uptake and glycogen content, which protects the heart from the development of the ischemic contracture, but not for contractile recovery in the absence of fatty acids.
The protein kinase C pathway mediates cardioprotection induced by cardiac-specific overexpression of fibroblast growth factor-2
Authors: House Stacey L. , Melhorn Susan J. , Newman Gilbert , Doetschman Thomas , Schultz Jo El J.
Published: March 2007

Elucidation of protective mechanisms against ischemia-reperfusion injury is vital to the advancement of therapeutics for ischemic heart disease. Our laboratory has previously shown that cardiac-specific overexpression of fibroblast growth factor-2 (FGF2) results in increased recovery of contractile function and decreased infarct size following ischemia-reperfusion injury and has established a role for the mitogen-activated protein kinase (MAPK) signaling cascade in the cardioprotective effect of FGF2. We now show an additional role for the protein kinase C (PKC) signaling cascade in the mediation of FGF2-induced cardioprotection. Overexpression of FGF2 ( FGF2 Tg) in the heart resulted in decreased translocation of PKC-δ but had no effect on PKC-α, -ε, or -ζ. In addition, multiple alterations in PKC isoform translocation occur during ischemia-reperfusion injury in FGF2 Tg hearts as assessed by Western blot analysis and confocal immunofluorescent microscopy. Treatment of FGF2 Tg and nontransgenic (NTg) hearts with the PKC inhibitor bisindolylmaleimide (1 μmol/l) revealed the necessity of PKC signaling for FGF2-induced reduction of contractile dysfunction and myocardial infarct size following ischemia-reperfusion injury. Western blot analysis of FGF2 Tg and NTg hearts subjected to ischemia-reperfusion injury in the presence of a PKC pathway inhibitor (bisindolylmaleimide, 1 μmol/l), an mitogen/extracellular signal-regulated kinase/extracellular signal-regulated kinase (MEK/ERK) pathway inhibitor (U-0126, 2.5 μmol/l), or a p38 pathway inhibitor (SB-203580, 2 μmol/l) revealed a complicated signaling network between the PKC and MAPK signaling cascades that may participate in FGF2-induced cardioprotection. Together, these data suggest that FGF2-induced cardioprotection is mediated via a PKC-dependent pathway and that the PKC and MAPK signaling cascades are integrally connected downstream of FGF2.
TNF-α downregulates transient outward potassium current in rat ventricular myocytes through iNOS overexpression and oxidant species generation
Authors: Fernández-Velasco María , Ruiz-Hurtado Gema , Hurtado Olivia , Moro Maria Ángeles , Delgado Carmen
Published: March 2007

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine that has been implicated in the pathogenesis of heart failure. Prolongation of the action potential duration and downregulation of several K+currents might participate in the genesis of arrhythmias associated with chronic heart failure. Little information is available related to the mechanism by which TNF-α modulates cardiac K+channels. The present study analyzes the effect of TNF-α on the transient outward K+current ( Ito) in rat ventricular myocytes, using the whole cell patch-clamp technique. We found that TNF-α is able to induce a significant reduction of Itodensity, modifies its inactivation, and downregulates the Kv4.2 protein expression, while calcium current density is not affected. We have also demonstrated that the reduction of Itodensity induced by TNF-α was prevented by the selective inducible nitric oxide synthase (iNOS) inhibitor 1400-W, the protein synthesis inhibitor cycloheximide, the antioxidant tocopherol, and the superoxide dismutase mimetic manganese(III) tetrakis (4-benzoic acid) porphyrin. In addition, a reduced Itodensity was recorded in ventricular myocytes exposed to peroxynitrite, supporting a possible participation of this oxidant in the effects of TNF-α on Ito. We conclude that TNF-α exposure, through iNOS induction and generation of oxidant species, promotes electrophysiological changes (decreased Itoand action potential duration prolongation) in rat ventricular myocytes, providing new insights into how cytokines modulate K+channels in the heart.
Heat shock protein 90 modulates endothelial nitric oxide synthase activity and vascular reactivity in the newborn piglet pulmonary circulation
Authors: Aschner Judy L. , Foster Susan L. , Kaplowitz Mark , Zhang Yongmei , Zeng Heng , Fike Candice D.
Published: March 2007

Heat shock protein 90 (Hsp90) binding to endothelial nitric oxide synthase (eNOS) is an important step in eNOS activation. The conformational state of bound Hsp90 determines whether eNOS produces nitric oxide (NO) or superoxide (O2•−). We determined the effects of the Hsp90 antagonists geldanamycin (GA) and radicicol (RA) on basal and ACh-stimulated changes in vessel diameter, cGMP production, and Hsp90:eNOS coimmunoprecipitation in piglet resistance level pulmonary arteries (PRA). In perfused piglet lungs, we evaluated the effects of GA and RA on ACh-stimulated changes in pulmonary arterial pressure (Ppa) and perfusate accumulation of stable NO metabolites (NOx−). The effects of GA and RA on ACh-stimulated O2•− generation was investigated in cultured pulmonary microvascular endothelial cells (PMVEC) by dihydroethidine (DHE) oxidation and confocal microscopy. Hsp90 inhibition with GA or RA reduced ACh-mediated dilation, abolished the ACh-stimulated increase in cGMP, and reduced eNOS:Hsp90 coprecipitation. GA and RA also inhibited the ACh-mediated changes in Ppa and NOx− accumulation rates in perfused lungs. ACh increased the rate of DHE oxidation in PMVEC pretreated with GA and RA but not in untreated cells. The cell-permeable superoxide dismutase mimetic M40401 reversed GA-mediated inhibition of ACh-induced dilation in PRA. We conclude that Hsp90 is a modulator of eNOS activity and vascular reactivity in the newborn piglet pulmonary circulation. Uncoupling of eNOS with GA or RA inhibits ACh-mediated dilation by a mechanism that involves O2•− generation.
Rietveld refinement of YbCoO3 prepared from aqueous solution-gel precursor
Authors: Farhat L. Ben , Hassen R. Ben , Dammak L.
Published: March 2007

A polycrystalline sample of
YbCoO3 was prepared using a water-soluble complex method at relatively low temperatures. Common chelating ligands such as citric acid were employed for the synthesis of complex-based precursors, followed by thermal decomposition of the precursors at high temperatures. X-ray diffraction data were collected and the crystal structure was refined by the Rietveld method. The structure of
YbCoO3 can be described as a sesquioxide
C-M2O3-like structure with space group Ia-3 and unit-cell parameter a=10.4470 (2). The
Yb3+ and the
Co3+ cations are found to preferentially occupy the two nonequivalent 8d and 24d sites, respectively. The two independent atoms
Yb/Co
have octahedral coordination; however, the degrees of distortion of their coordination polyhedron are different. The relationship between the title compound and the orthorhombic Perovskite structure of
YbCoO3 reported in the literature is established.
Crystal structures of three anhydrous nitroprussides: M[Fe(CN)5NO] (M=Mn, Zn, Cd)
Authors: Rodríguez-Hernández J. , Reguera E. , Mir M. , Mascarenhas Y. P.
Published: March 2007

The crystal structures of Mn, Zn, and Cd nitroprussides in their anhydrous state,
M[Fe(CN)5NO]
(M=Mn, Zn, Cd), were refined from XRD powder patterns using the Rietveld method. These compounds have a porous framework useful for adsorption and storage of small molecules. Water crystallization can be removed by heating below 100 °C without disrupting the 3D network by introducing certain structural modification mainly around the M site (Mn, Zn, Cd). For M=Mn and Cd, the compounds were found to be orthorhombic with space group Pnma [Mn:a=13.7844(1), b=7.3750(2), c=10.9470(2) Å, V=1112.8(1) Å3, Z=4; Cd:a=13.9566(3), b=7.5040(4), c=11.0230(2) Å, V=1154.4(1) Å3, Z=4]. Anhydrous zinc nitroprusside crystallizes in rhombohedral with space group R3 [a=b=19.2525(1), c=17.7107(2) Å, γ=120.0°, V=5685.1(1) Å3, Z=18]. When exposed to humid air, these anhydrous compounds become hydrated. The XRD powder patterns were recorded under vacuum on samples dehydrated in situ. The structural information from XRD was complemented with thermo-gravimetric, infrared, and Mössbauer data.
Crystal structures of newly synthesized SbV1.50FeIII0.50(PO4)3and (SbV0.50FeIII0.50)P2O7
Authors: Aatiq Abderrahim , Bakri Rachid
Published: March 2007

Synthesis and structure of two phosphates belonging to the ternary Sb2O5-Fe2O3-P2O5system are reported. Structures of both SbV1.50FeIII0.50(PO4)3and (SbV0.50FeIIIe0.50)P2O7phases, obtained by solid state reaction in air atmosphere at 950 °C and 900 °C, respectively, were determined at room temperature from X-ray powder diffraction using the Rietveld method. Sb1.50Fe0.50(PO4)3phosphate belongs to the Nasicon-type structure withR32 space group. Hexagonal cell parameters areahex.=8.305(1) Å andchex.=22.035(2) Å. Rietveld refinement results show a 2-2 ordered distribution, along thec-axis, ofX(1) andX(2) sites (crystallographic formula [Sb0.88Fe0.12]X(1)[Fe0.38Sb0.62]X(2)(PO4)3) in the Nasicon framework. (Sb0.50Fe0.50)P2O7is isotypic withβ-SbP2O7pyrophosphate [Pna21space group;a=7.865(1) Å,b=15.699(2) Å,c=7.847(1) Å]. Its crystal structure is built up from corner-shared SbO6or FeO6octahedra and P2O7groups (two group types). Each P2O7group shares its six vertices with three SbO6and three FeO6octahedra, and each octahedra is connected to six P2O7groups. A quasi 1-1 ordered distribution, along theb-axis, of Sb5+and Fe3+ions in the pyrophosphate framework are observed.
X-ray powder diffraction data for monoclinic metazachlor, 2-chloro-N-(pyrazol-1-ylmethyl) acetyl-2′, 6′-xylidide
Authors: Dunlevey J. N.
Published: March 2007

X-ray powder diffraction data and unit cells parameters for a monoclinic variety of the popular herbicide 2-chloro-N-(pyrazol-1-ylmethyl) acetyl-2′, 6′-xylidide, commonly known as metazachlor, butisan, and butichlor, is presented [a=7.306(3) Å,b=17.824(9) Å,c=10.728(3) Å,β=98.46(4)°, space groupP21/c, cell volume=1381.82 Å3,Z=4]. The four strongest peaks (Irel>25) at 8.87, 7.19, 4.57, and 4.45 Å are quite distinctive, thus X-ray powder diffraction provides a quick, simple, and definitive method of identifying this form of material from other commercially available herbicide products.
Fatty Infiltration and Atrophy of the Rotator Cuff do not Improve after Rotator Cuff Repair and Correlate with Poor Functional Outcome
Authors: Gladstone James N. , Bishop Julie Y. , Lo Ian K.Y. , Flatow Evan L.
Published: March 2007

Background

The role of degenerative changes in rotator cuff musculature with respect to the functional outcomes of rotator cuff repair have only recently been recognized and are still not well understood. In addition, the reversibility of these changes with repair of the tendons is questionable.

Hypothesis

Poorer preoperative muscle quality negatively affects outcome, and a successful outcome (in terms of a healed repair) might demonstrate improvements in fatty infiltration and muscle atrophy.

Study Design

Cohort study; Level of evidence, 2.

Methods

Thirty-eight patients (mean age, 62 years) were prospectively evaluated with preoperative and 1-year postoperative clinical examination and appropriate magnetic resonance image sequencing to determine grades of muscle atrophy and fatty infiltration of the supraspinatus and infraspinatus muscles. American Shoulder and Elbow Society (ASES), Constant, and pain scores were determined as well as strength measurements. The retear rate and progression of muscle degeneration were also evaluated. Independent predictors of outcome measurements and cuff integrity were determined.

Results

The overall clinical outcome, including ASES, Constant, and pain scores, improved significantly (P < .0001). Strength in forward elevation improved significantly (P < .006), while external rotation strength did not. There was a strongly negative correlation between muscle quality and outcome results in most cases. When the results were adjusted for multivariate effect, muscle atrophy and fatty infiltration of the infraspinatus muscle were the only independent predictors of ASES and Constant scores (P < .03). Tear size and rotator cuff healing did not play an independent role. Tear size, however, was the only independent predictor of ultimate cuff integrity (P = .002). Both atrophy and fatty infiltration progressed significantly over the course of the study. In cases in which the tendon had re-torn, the progression was found to be more significant than when the repair proved successful (P < .003).

Conclusion

Muscle atrophy and fatty infiltration of the rotator cuff muscles, particularly of the infraspinatus, play a significant role in determining functional outcome after cuff repair. Tear size appears to have the most influential effect on repair integrity. A successful repair did not lead to improvement or reversal of muscle degeneration and a failed repair resulted in significantly more progression. In general, healed repairs demonstrated minimal progression. These findings suggest that repairs should be performed, if possible, before more significant deterioration in the cuff musculature in order to optimize outcomes, and that understanding the degree of muscle atrophy and fatty infiltration before surgery can help guide patient expectations.
Transformative Considerations
Authors: Mertens Donna M.
Published: March 2007

Should the Russians be included in the evaluation and, if so, how can that be done? Based on the axiological assumption that the social justice theory of ethics leads to an awareness of the need to redress inequalities by giving precedence, or at least equal weight, to the voice of the least advantaged groups in society who may not have sufficient power for accurate representation among the stakeholder groups, the ethical path leads to answering this query in the affirmative. The axiological focus on the strengths of the community provides one avenue to addressing this issue through an exploration of options for partnership and community involvement.
Association of the diplotype configuration at the N-acetyltransferase 2 gene with adverse events with co-trimoxazole in Japanese patients with systemic lupus erythematosus
Authors: Soejima Makoto , Sugiura Tomoko , Kawaguchi Yasushi , Kawamoto Manabu , Katsumata Yasuhiro , Takagi Kae , Nakajima Ayako , Mitamura Tadayuki , Mimori Akio , Hara Masako , Kamatani Naoyuki
Published: March 2007

Although co-trimoxazole (trimethoprim-sulphamethoxazole) is an effective drug for prophylaxis against and treatment ofPneumocystispneumonia, patients often experience adverse events with this combination, even at prophylactic doses. With the aim being to achieve individual optimization of co-trimoxazole therapy in patients with systemic lupus erythematosus (SLE), we investigated genetic polymorphisms in theNAT2gene (which encodes the metabolizing enzyme of sulphamethoxazole). Of 166 patients with SLE, 54 patients who were hospitalized and who received prophylactic doses of co-trimoxazole were included in the cohort study. Adverse events occurred in 18 patients; only two experienced severe adverse events that lead to discontinuation of the drug. These two patients and three additional ones with severe adverse events (from other institutions) were added to form a cohort sample and were analyzed in a case-control study. Genotype was determined using TaqMan methods, and haplotype was inferred using the maximum-likelihood method. In the cohort study, adverse events occurred more frequently in those without theNAT2*4haplotype (5/7 [71.4%]) than in those with at least oneNAT2*4haplotype (13/47 [27.7%];P= 0.034; relative risk = 2.58, 95% confidence interval = 1.34–4.99). In the case-control study the proportion of patients withoutNAT2*4was significantly higher among those with severe adverse events (3/5 [60%]) than those without severe adverse events (6/52 [11.5%];P= 0.024; odds ratio = 11.5, 95% confidence interval = 1.59–73.39). We conclude that lack ofNAT2*4haplotype is associated with adverse events with co-trimoxazole in Japanese patients with SLE.
The major vault protein is related to the toxic anion resistance protein(TelA) family
Authors: Suprenant Kathy A. , Bloom Nathan , Fang Jianwen , Lushington Gerald
Published: March 2007

Vaults are barrel-shaped ribonucleoprotein particles that are abundant in certain tumors and multidrug resistant cancer cells. Prokaryotic relatives of the major vault protein, MVP, have not been identified. We used sequence analysis and molecular modeling to show that MVP and the toxic anion resistance protein, TelA of Rhodobacter sphaeroides strain 2.4.1,share a novel fold that consists of a three-stranded antiparallelβ-sheet. Because of this strong structural correspondence, we examined whether mammalian cell vaults respond to tellurite treatment. In the presence of the oxyanion tellurite, large vault aggregates, or vaultosomes, appear at the cell periphery in 15 min or less. Vaultosome formation is temperature-dependent, reversible, and occurs in normal human umbilical vein endothelial cells as well as transformed HeLa cervical cancer cells. Vaultosome formation is not restricted to tellurite and occurs in the presence of other toxic oxyanions (selenate, selinite, arsenate, arsenite, vanadate). In addition, vaultosomes form independently from other stress-induced ribonucleoprotein complexes, stress granules and aggresomes. Vaultosome formation is therefore a unique cellular response to an environmental toxin.
Clicking caterpillars: acoustic aposematism inAntheraea polyphemusand other Bombycoidea
Authors: Brown Sarah G. , Boettner George H. , Yack Jayne E.
Published: March 2007

Acoustic signals produced by caterpillars have been documented for over 100 years, but in the majority of cases their significance is unknown. This study is the first to experimentally examine the phenomenon of audible sound production in larval Lepidoptera, focusing on a common silkmoth caterpillar, Antheraea polyphemus (Saturniidae). Larvae produce airborne sounds,resembling `clicks', with their mandibles. Larvae typically signal multiple times in quick succession, producing trains that last over 1 min and include 50–55 clicks. Individual clicks within a train are on average 24.7 ms in duration, often consisting of multiple components. Clicks are audible in a quiet room, measuring 58.1–78.8 dB peSPL at 10 cm. They exhibit a broadband frequency that extends into the ultrasound spectrum, with most energy between 8 and 18 kHz. Our hypothesis that clicks function as acoustic aposematic signals, was supported by several lines of evidence. Experiments with forceps and domestic chicks correlated sound production with attack, and an increase in attack rate was positively correlated with the number of signals produced. In addition, sound production typically preceded or accompanied defensive regurgitation. Bioassays with invertebrates (ants) and vertebrates (mice) revealed that the regurgitant is deterrent to would-be predators. Comparative evidence revealed that other Bombycoidea species,including Actias luna (Saturniidae) and Manduca sexta(Sphingidae), also produce airborne sounds upon attack, and that these sounds precede regurgitation. The prevalence and adaptive significance of warning sounds in caterpillars is discussed.
Temperature dependent modulation of lobster neuromuscular properties by serotonin
Authors: Hamilton Jonna L. , Edwards Claire R. , Holt Stephen R. , Worden Mary Kate
Published: March 2007

In cold-blooded species the efficacy of neuromuscular function depends both on the thermal environmental of the animal's habitat and on the concentrations of modulatory hormones circulating within the animal's body. The goal of this study is to examine how temperature variation within an ecologically relevant range affects neuromuscular function and its modulation by the neurohormone serotonin (5-HT) in Homarus americanus, a lobster species that inhabits a broad thermal range in the wild. The synaptic strength of the excitatory and inhibitory motoneurons innervating the lobster dactyl opener muscle depends on temperature, with the strongest neurally evoked muscle movements being elicited at cold (<5°C) temperatures. However, whereas neurally evoked contractions can be elicited over the entire temperature range from 2 to >20°C, neurally evoked relaxations of resting muscle tension are effective only at colder temperatures at which the inhibitory junction potentials are hyperpolarizing in polarity. 5-HT has two effects on inhibitory synaptic signals: it potentiates their amplitude and also shifts the temperature at which they reverse polarity by approximately +7°C. Thus 5-HT both potentiates neurally evoked relaxations of the muscle and increases the temperature range over which neurally evoked muscle relaxations can be elicited. Neurally evoked contractions are maximally potentiated by 5-HT at warm (18°C) temperatures; however, 5-HT enhances excitatory junction potentials in a temperature-independent manner. Finally, 5-HT strongly increases resting muscle tension at the coldest extent of the temperature range tested (2°C) but is ineffective at 22°C. These data demonstrate that 5-HT elicits several temperature-dependent physiological changes in the passive and active responses of muscle to neural input. The overall effect of 5-HT is to increase the temperature range over which neurally evoked motor movements can be elicited in this neuromuscular system.)
Ideologies of moral exclusion: A critical discursive reframing of depersonalization, delegitimization and dehumanization
Authors: Tileagă Cristian
Published: March 2007

This paper focuses on some of the issues that arise when one treats notions such as depersonalization, delegitimization and dehumanization as social practices. It emphasizes the importance of: (a) understanding depersonalizing, delegitimizing and dehumanizing constructions as embedded in descriptions of located spatial activities and moral standings in the world and (b) invoking and building a socio‐moral order linked to notions of lesser humanity or non‐humanity, (spatial) transgression and abjection. These concerns are illustrated by taking talk on Romanies as a case in point from interviews with Romanian middle‐class professionals. It is argued that a focus on description rather than explanation might be more effective in understanding the dynamics of ideologies of moral exclusion.
In the ruins of representation: Identity, individuality, subjectification
Authors: Papadopoulos Dimitris
Published: March 2007

This paper explores a threefold shift in our understanding of identity formation and self‐relationality: from an essentialist understanding of identity, to discursive and constructivist approaches, to, finally, the notion of embodied subjectification. The main target of this paper is to historicize these ideas and to localize them in the current social and political conditions of North‐Atlantic societies. The core argument is that these three steps in reformulating the concept of identity correspond to an emerging form of subjectivity, affirmative subjectivity, which is bound to the proliferation of the post‐Fordist reorganization of the social and political realm. The three theoretical shifts and their social situatedness will be illustrated through a rereading of some ideas from Lev S. Vygotsky's late theory, Michel Foucault's account of government and Jacques Rancière's political philosophy.
Infants can infer the presence of hidden objects from referential gaze information
Authors: Csibra Gergely. , Volein Ágnes.
Published: March 2007

Infants' apparent failure in gaze‐following tasks is often interpreted as a sign of lack of understanding the referential nature of looking. In the present study, 8‐ and 12‐month‐old infants followed the gaze of a model to one of two locations hidden from their view by occluders. When the occluders were removed, an object was revealed either at the location where the model had looked or at the other side. Infants at both ages looked longer at the empty location when it had been indicated by the model's looking behaviour, and this effect held up even when their first look after gaze following was discounted. This result demonstrates that even young infants hold referential expectations when they follow others' gaze and infer the location of hidden objects accordingly.
Five‐ to twelve‐year‐olds' control of movement velocity in a dynamic collision avoidance task
Authors: te Velde Arenda F. , van der Kamp John. , Savelsbergh Geert J. P.
Published: March 2007

We investigated age‐related differences in a dynamic collision avoidance task that bears a resemblance to pedestrian road crossing. Five‐ to seven‐year‐old children, ten‐ to twelve‐year‐old children and adults were instructed to push a doll across a small‐scale road between two toy vehicles, which approached one after the other. We analysed the number of attempted crossings, the number of collisions, movement onset times and movement velocity control. The youngest children attempted to cross less often, but collided more frequently than the adults. This age effect could be attributed to differences in the way the children and adults controlled movement velocity. The youngest children attained the velocity that was required for safe travel too late, particularly when the gaps between the toy vehicles were small. The age differences in movement onset strategies were less clear‐cut. The findings are discussed within a framework that proposes distinct roles of vision in action planning and action production.