Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

The EBV Immunoevasins vIL-10 and BNLF2a Protect Newly Infected B Cells from Immune Recognition and Elimination

Lifelong persistence of Epstein-Barr virus (EBV) in infected hosts is mainly owed to the virus' pronounced abilities to evade immune responses of its human host. Active immune evasion mechanisms reduce the immunogenicity of infected cells and are known to be of major importance during lytic infection. The EBV genes BCRF1 and BNLF2a encode the viral homologue of IL-10 (vIL-10) and an inhibitor of the transporter associated with antigen processing (TAP), respectively. Both are known immunoevasins in EBV's lytic phase. Here we describe that BCRF1 and BNLF2a are functionally expressed instantly upon infection of primary B cells. Using EBV mutants deficient in BCRF1 and BNLF2a, we show that both factors contribute to evading EBV-specific immune responses during the earliest phase of infection. vIL-10 impairs NK cell mediated killing of infected B cells, interferes with CD4+ T-cell activity, and modulates cytokine responses, while BNLF2a reduces antigen presentation and recognition of newly infected cells by EBV-specific CD8+ T cells. Together, both factors significantly diminish the immunogenicity of EBV-infected cells during the initial, pre-latent phase of infection and may improve the establishment of a latent EBV infection in vivo

Noise Reduction by Diffusional Dissipation in a Minimal Quorum Sensing Motif

Cellular interactions are subject to random fluctuations (noise) in quantities of interacting molecules. Noise presents a major challenge for the robust function of natural and engineered cellular networks. Past studies have analyzed how noise is regulated at the intracellular level. Cell–cell communication, however, may provide a complementary strategy to achieve robust gene expression by enabling the coupling of a cell with its environment and other cells. To gain insight into this issue, we have examined noise regulation by quorum sensing (QS), a mechanism by which many bacteria communicate through production and sensing of small diffusible signals. Using a stochastic model, we analyze a minimal QS motif in Gram-negative bacteria. Our analysis shows that diffusion of the QS signal, together with fast turnover of its transcriptional regulator, attenuates low-frequency components of extrinsic noise. We term this unique mechanism “diffusional dissipation” to emphasize the importance of fast signal turnover (or dissipation) by diffusion. We further show that this noise attenuation is a property of a more generic regulatory motif, of which QS is an implementation. Our results suggest that, in a QS system, an unstable transcriptional regulator may be favored for regulating expression of costly proteins that generate public goods

Interplay between SIN3A and STAT3 Mediates Chromatin Conformational Changes and GFAP Expression during Cellular Differentiation

BACKGROUND: Neurons and astrocytes are generated from common neural precursors, yet neurogenesis precedes astrocyte formation during embryogenesis. The mechanisms of neural development underlying suppression and de-suppression of differentiation-related genes for cell fate specifications are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: By using an in vitro system in which NTera-2 cells were induced to differentiate into an astrocyte-like lineage, we revealed a novel role for Sin3A in maintaining the suppression of GFAP in NTera-2 cells. Sin3A coupled with MeCP2 bound to the GFAP promoter and their occupancies were correlated with repression of GFAP transcription. The repression by Sin3A and MeCP2 may be an essential mechanism underlying the inhibition of cell differentiation. Upon commitment toward an astrocyte-like lineage, Sin3A- MeCP2 departed from the promoter and activated STAT3 simultaneously bound to the promoter and exon 1 of GFAP; meanwhile, olig2 was exported from nuclei to the cytoplasm. This suggested that a three-dimensional or higher-order structure was provoked by STAT3 binding between the promoter and proximal coding regions. STAT3 then recruited CBP/p300 to exon 1 and targeted the promoter for histone H3K9 and H3K14 acetylation. The CBP/p300-mediated histone modification further facilitates chromatin remodeling, thereby enhancing H3K4 trimethylation and recruitment of RNA polymerase II to activate GFAP gene transcription. CONCLUSIONS/SIGNIFICANCE: These results provide evidence that exchange of repressor and activator complexes and epigenetic modifications are critical strategies for cellular differentiation and lineage-specific gene expression

Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

Peer reviewe

THREONYL-TRANSFER RNA-SYNTHETASE FROM BOVINE LIVER - PURIFICATION AND KINETIC-PROPERTIES IN THE ATP-PYROPHOSPHATE EXCHANGE-REACTION

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Inhibition of acid phosphatase isoforms purified from mature soybean (Glycine max) seeds

The four soybean seed acid phosphatase isoforms API, AP2, AP3A and AP3B were competitively inhibited by phosphate, vanadate, fluoride and molybdate, using p-nitrophenylphosphate as substrate. The four isoforms were not significantly affected by compounds that can interact with SH residues or by pyridoxal phosphate. These results indicated that cysteine and lysine residues are not present in the active site of the four soybean seed acid phosphatase isoforms. The inhibition constant values for phosphate, vanadate, fluoride and molybdate at pH 5.0 were respectively: API (250, 12.8, 1.7, 0.05 mu M), AP2 (800, 10, 500, 0.025 mu M), AP3A (250, 24.2, 250, 0.032 mu M), AP3B (2400, 36.9, 750, 0.05 mu M).15440341

Glycolytic intermediates as substrates of soybean acid phosphatase isoforms

The kinetic properties of four isoforms of acid phosphatase purified from mature soybean (Glycine max) seeds were studied using glycolytic metabolites as substrates. The isoforms AP1, AP3A and AP3B presented maximal activities around pH 4.0, and AP2 at pH 6.0, for phosphoenolpyruvate (PEP) as a substrate. With glucose-6-P (G6P) and fructose-6-P (F6P) maximal activities were observed at pH 5.5 for the AP3A and AP3B isoforms. The acid phosphatases presented the following apparent K-m values, at the corresponding optimum pH values: AP1 (p-nitrophenylphosphate (pNPP): 0.49, PEP: 0.23 mM); AP2 (pNPP: 0.38, PEP: 0.47 mM); AP3A (pNPP: 0.20, PEP: 0.10, G6P: 0.30, F6P: 0.16 mM) and AP3B (pNPP: 0.086, PEP: 0.078, G6P: 0.31, F6P: 0.33 mM). Maximal specificity constant (V-max/K-m) was obtained for the isoform:AP1, with PEP as a substrate. Independent of the substrates, the reactions catalyzed by the soybean acid phosphatase isoforms were potently inhibited by molybdate and to a lesser extent by Zn2+. Inhibitions were also observed in the presence of fluoride, with PEP as a substrate, and by Cu2+, and p-chloromercuribenzoate (pCMB) with G6P and F6P as substrates. Our results suggest that the Four acid phosphatase forms could play important roles in plant metabolism, acting on key glycolytic intermediates. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.1471495

K. G. WETTERLUND: Några tull- och handelspolitiska spörsmål. Udg. af Skånes Handelskammare, -U S. Malmø 1918.

The effects of two lectins concanavalin A (conA) and soybean agglutinin, on soybean seed acid phosphatase activity were investigated using p-nitrophenylphosphate (pNPP), pyrophosphate (PPi) and phosphoenolpyruvate (PEP) as substrates. Of the four acid phosphatase isoforms (AP1, AP2, AP3A and AP3B) purified from soybean seeds, only API was activated 40 and 60% by conA and soybean agglutinin, respectively. Both lectins affected some of the kinetic parameters of AP1. The activation by lectins was not affected by 1 mM Ca2+ or Mn2+ but glucose and methylmannopyranoside (100 mM) prevented activation by conA. Under the same conditions, galactose had no effect. These results suggest that plant acid phosphatases may be regulated by lectins, the effects vary according to the substrate used. (C) 2001 Elsevier Science Ltd. All rights reserved.58222122