SU(N) Coherent States and Irreducible Schwinger Bosons

We exploit the SU(N) irreducible Schwinger boson to construct SU(N) coherent states. This construction of SU(N) coherent state is analogous to the construction of the simplest Heisenberg-Weyl coherent states. The coherent states belonging to irreducible representations of SU(N) are labeled by the eigenvalues of the $(N-1)$ SU(N) Casimir operators and are characterized by $(N-1)$ complex orthonormal vectors describing the SU(N) group manifold.Comment: 12 pages, 3 figure

Metabolic labeling of RNA uncovers principles of RNA production and degradation dynamics in mammalian cells

available in PMC 2011 November 01.Cellular RNA levels are determined by the interplay of RNA production, processing and degradation. However, because most studies of RNA regulation do not distinguish the separate contributions of these processes, little is known about how they are temporally integrated. Here we combine metabolic labeling of RNA at high temporal resolution with advanced RNA quantification and computational modeling to estimate RNA transcription and degradation rates during the response of mouse dendritic cells to lipopolysaccharide. We find that changes in transcription rates determine the majority of temporal changes in RNA levels, but that changes in degradation rates are important for shaping sharp 'peaked' responses. We used sequencing of the newly transcribed RNA population to estimate temporally constant RNA processing and degradation rates genome wide. Degradation rates vary significantly between genes and contribute to the observed differences in the dynamic response. Certain transcripts, including those encoding cytokines and transcription factors, mature faster. Our study provides a quantitative approach to study the integrative process of RNA regulation.Human Frontier Science Program (Strasbourg, France)Howard Hughes Medical InstituteBurroughs Wellcome Fund (Career Award at the Scientific Interface

Prepotential formulation of SU(3) lattice gauge theory

The SU(3) lattice gauge theory is reformulated in terms of SU(3) prepotential harmonic oscillators. This reformulation has enlarged $SU(3)\otimes U(1) \otimes U(1)$ gauge invariance under which the prepotential operators transform like matter fields. The Hilbert space of SU(3) lattice gauge theory is shown to be equivalent to the Hilbert space of the prepotential formulation satisfying certain color invariant Sp(2,R) constraints. The SU(3) irreducible prepotential operators which solve these Sp(2,R) constraints are used to construct SU(3) gauge invariant Hilbert spaces at every lattice site in terms of SU(3) gauge invariant vertex operators. The electric fields and the link operators are reconstructed in terms of these SU(3) irreducible prepotential operators. We show that all the SU(3) Mandelstam constraints become local and take very simple form within this approach. We also discuss the construction of all possible linearly independent SU(3) loop states which solve the Mandelstam constraints. The techniques can be easily generalized to SU(N).Comment: 25 pages, 10 figures, LaTeX, Minor modifications done. Version to appear in J. Phys. A: Mathematical and General, 43 (2010

Vasopressin receptor-mediated functional signaling pathway in primary cilia of renal epithelial cells

The primary cilium of renal epithelial cells is a nonmotile sensory organelle, implicated in mechanosensory transduction signals. Recent studies from our laboratory indicate that renal epithelial primary cilia display abundant channel activity; however, the presence and functional role of specific membrane receptors in this organelle are heretofore unknown. Here, we determined a functional signaling pathway associated with the type 2 vasopressin receptor (V2R) in primary cilia of renal epithelial cells. Besides their normal localization on basolateral membrane, V2R was expressed in primary cilia of LLC-PK1 renal epithelial cells. The presence of V2R in primary cilia was determined by spontaneous fluorescence of a V2R-gfp chimera and confirmed by immunocytochemical analysis of wild-type LLC-PK1 cells stained with anti-V2R antibodies and in LLC-PK1 cells overexpressing the V2R-Flag, with anti-Flag antibody. Ciliary V2R colocalized with adenylyl cyclase (AC) type V/VI in all cell types tested. Functional coupling of the receptors with AC was confirmed by measurement of cAMP production in isolated cilia and by testing AVP-induced cation-selective channel activity either in reconstituted lipid bilayers or subjected to membrane-attached patch clamping. Addition of either 10 μM AVP (trans) or forskolin (cis) in the presence but not the absence of ATP (1 mM, cis) stimulated cation-selective channel activity in ciliary membranes. This channel activity was reduced by addition of the PKA inhibitor PKI. The data provide the first demonstration for the presence of V2R in primary cilia of renal epithelial cells, and a functional cAMP-signaling pathway, which targets ciliary channel function and may help control the sensory function of the primary cilium.Fil: Raychowdhury, Malay K.. Massachusetts General Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: Ramos, Arnolt J.. Massachusetts General Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: Zhang, Peng. Massachusetts General Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: McLaughin, Margaret. Harvard Medical School; Estados Unidos. Massachusetts General Hospital; Estados UnidosFil: Dai, Xiao-Qing. University of Alberta; CanadáFil: Chen, Xing-Zhen. University of Alberta; CanadáFil: Montalbetti, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Cantero, Maria del Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Ausiello, Dennis A.. Massachusetts General Hospital; Estados Unidos. Harvard Medical School; Estados UnidosFil: Cantiello, Horacio Fabio. Massachusetts General Hospital; Estados Unidos. Harvard Medical School; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentin

Characterization of Na+-permeable cation channels in LLC-PK1 renal epithelial cells

In this study, the presence of Na+-permeable cation channels was determined and characterized in LLC-PK1 cells, a renal tubular epithelial cell line with proximal tubule characteristics derived from pig kidney. Patch-clamp analysis under cell-attached conditions indicated the presence of spontaneously active Na+-permeable cation channels. The channels displayed nonrectifying single channel conductance of 11 pS, substates, and an ∼3:1 Na+/K+ permeability-selectivity ratio. The Na+-permeable cation channels were inhibited by pertussis toxin and reactivated by G protein agonists. Cation channel activity was observed in quiescent cell-attached patches after vasopressin stimulation. The addition of protein kinase A and ATP to excised patches also induced Na+ channel activity. Spontaneous and vasopressin-induced Na+ channel activity were inhibited by extracellular amiloride. To begin assessing potential molecular candidates for this cation channel, both reverse transcription-PCR and immunocytochemical analyses were conducted in LLC-PK1 cells. Expression of porcine orthologs of the αENaC and ApxL genes were found in LLC-PK1 cells. The expression of both gene products was confirmed by immunocytochemical analysis. Although αENaC labeling was mostly intracellular, ApxL labeled to both the apical membrane and cytoplasmic compartments of subconfluent LLC-PK1 cells. Vasopressin stimulation had no effect on αENaC immunolabeling but modified the cellular distribution of ApxL, consistent with an increased membrane-associated ApxL. The data indicate that proximal tubular LLC-PK1 renal epithelial cells express amiloride-sensitive, Na+-permeable cation channels, which are regulated by the cAMP pathway, and G proteins. This channel activity may implicate previously reported epithelial channel proteins, although this will require further experimentation. The evidence provides new clues as to potentially relevant Na+ transport mechanisms in the mammalian proximal nephron.Fil: Raychowdhury, Malay K.. Harvard Medical School; Estados Unidos. Massachusetts General Hospital East; Estados UnidosFil: Ibarra, Cristina Adriana. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Damiano, Alicia Ermelinda. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jackson Jr., George R.. Massachusetts General Hospital East; Estados UnidosFil: Smith, Peter R.. University of Alabama at Birmingahm; Estados UnidosFil: McLaughlin, Margaret. Massachusetts General Hospital East; Estados UnidosFil: Prat, Adriana G.. Massachusetts General Hospital East; Estados Unidos. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Ausiello, Dennis A.. Harvard Medical School; Estados Unidos. Massachusetts General Hospital East; Estados UnidosFil: Lader, Alan S.. Harvard Medical School; Estados Unidos. Massachusetts General Hospital East; Estados UnidosFil: Cantiello, Horacio Fabio. Massachusetts General Hospital East; Estados Unidos. Harvard Medical School; Estados Unidos. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Association between Low Density Lipoprotein Receptor-Related Protein 2 Gene Polymorphisms and Bone Mineral Density Variation in Chinese Population

Low density lipoprotein receptor-related protein 2 gene (LRP2) is located next to the genomic region showing suggestive linkage with both hip and wrist bone mineral density (BMD) phenotypes. LRP2 knockout mice showed severe vitamin D deficiency and bone disease, indicating the involvement of LRP2 in the preservation of vitamin D metabolites and delivery of the precursor to the kidney for the generation of 1α,25(OH)2D3. In order to investigate the contribution of LRP2 gene polymorphisms to the variation of BMD in Chinese population, a total of 330 Chinese female-offspring nuclear families with 1088 individuals and 400 Chinese male-offspring nuclear families with 1215 individuals were genotyped at six tagSNPs of the LRP2 gene (rs2389557, rs2544381, rs7600336, rs10210408, rs2075252 and rs4667591). BMD values at the lumbar spine 1–4 (L1-4) and hip sites were measured by DXA. The association between LRP2 polymorphisms and BMD phenotypes was assessed by quantitative transmission disequilibrium tests (QTDTs) in female- and male-offspring nuclear families separately. In the female-offspring nuclear families, rs2075252 and haplotype GA of rs4667591 and rs2075252 were identified in the nominally significant total association with peak BMD at L1-4; however, no significant within-family association was found between peak BMD at the L1-4 and hip sites and six tagSNPs or haplotypes. In male-offspring nuclear families, neither the six tagSNPs nor the haplotypes was in total association or within-family association with the peak BMD variation at the L1-4 and hip sites by QTDT analysis. Our findings suggested that the polymorphisms of LRP2 gene is not a major factor that contributes to the peak BMD variation in Chinese population

The Role of Proteasome Beta Subunits in Gastrin-Mediated Transcription of Plasminogen Activator Inhibitor-2 and Regenerating Protein1

The hormone gastrin physiologically regulates gastric acid secretion and also contributes to maintaining gastric epithelial architecture by regulating expression of genes such as plasminogen activator inhibitor 2 (PAI-2) and regenerating protein 1(Reg1). Here we examine the role of proteasome subunit PSMB1 in the transcriptional regulation of PAI-2 and Reg1 by gastrin, and its subcellular distribution during gastrin stimulation. We used the gastric cancer cell line AGS, permanently transfected with the CCK2 receptor (AGS-GR) to study gastrin stimulated expression of PAI-2 and Reg1 reporter constructs when PSMB1 was knocked down by siRNA. Binding of PSMB1 to the PAI-2 and Reg1 promoters was assessed by chromatin immunoprecipitation (ChIP) assay. Subcellular distribution of PSMB1 was determined by immunocytochemistry and Western Blot. Gastrin robustly increased expression of PAI-2 and Reg1 in AGS-GR cells, but when PSMB1 was knocked down the responses were dramatically reduced. In ChIP assays, following immunoprecipitation of chromatin with a PSMB1 antibody there was a substantial enrichment of DNA from the gastrin responsive regions of the PAI-2 and Reg1 promoters compared with chromatin precipitated with control IgG. In AGS-GR cells stimulated with gastrin there was a significant increase in the ratio of nuclear:cytoplasmic PSMB1 over the same timescale as recruitment of PSMB1 to the PAI-2 and Reg1 promoters seen in ChIP assays. We conclude that PSMB1 is part of the transcriptional machinery required for gastrin stimulated expression of PAI-2 and Reg1, and that its change in subcellular distribution in response to gastrin is consistent with this role

Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

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