Characterizing light attenuation within Northwest Florida ...

EPA Pesticide Factsheets

Water Quality (WQ) condition is based on ecosystem stressor indicators (e.g. water clarity) which are biogeochemically important and critical when considering the Deepwater Horizon oil spill restoration efforts under the 2012 RESTORE Act. Nearly all of the proposed RESTORE projects list restoring WC as a goal, but 90% neglect water clarity. Here, dynamics of optical constituents impacting clarity are presented from a 2009-2011 study within Pensacola, Choctawhatchee, St. Andrew and St. Joseph estuaries (targeted RESTORE sites) in Northwest Florida. Phytoplankton were the smallest contribution to total absorption (at-wPAR) at 412 nm (5-11%), whereas colored dissolved organic matter was the largest (61-79%). Estuarine at-wPAR was significantly related to light attenuation (KdPAR), where individual contributors to clarity and the influence of climatic events were discerned. Provided are conversion equations demonstrating interoperability of clarity indicators between traditional State-measured WQ measures (e.g. secchi disc), optical constituents, and even satellite remote sensing for obtaining baseline assessments. This paper arose from efforts under SSWR and SHC to utilize water quality data as baseline measures for RESTORE Act monitoring in Florida estuaries. This paper aims to (1) describe dynamics of optical constituents that impact water clarity in four NW Florida estuaries, and (2) make a case for the total absorption coefficient (at-wPAR) as a valuable

Spectroscopic studies of micelle-enhanced ligand exchange of gallium (III)/4-(2-pyridylazo) resorcinol complex by calf thymus DNA.

PubMed

Romeika, Jennifer M; Spurgeon, Charina L; Yan, Fei

2014-01-03

The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of gallium (III) with 4-(2-pyridylazo) resorcinol (PAR) under varying conditions has been studied spectrophotometrically. At pH 6.0, CTAB (0.05% w/v) markedly enhanced the absorption intensity of gallium (III)-PAR complex. Furthermore, the introduction of CTAB provided unique selectivity for the ligand exchange of Ga(III)-PAR by calf thymus dsDNA over calf thymus ssDNA. This phenomenon offers a novel spectrophotometric sensing strategy for direct detection of dsDNA. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral estimators of absorbed photosynthetically active radiation in corn canopies

NASA Technical Reports Server (NTRS)

Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

1985-01-01

Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a Landsat MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95 percent of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50 percent of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73 percent of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

Spectral estimators of absorbed photosynthetically active radiation in corn canopies

NASA Technical Reports Server (NTRS)

Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

1984-01-01

Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a LANDSAT MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95% of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50% of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73% of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

Etude de la dynamique des porteurs dans des nanofils de silicium par spectroscopie terahertz

NASA Astrophysics Data System (ADS)

Beaudoin, Alexandre

Ce memoire presente une etude des proprietes de conduction electrique et de la dynamique temporelle des porteurs de charges dans des nanofils de silicium sondes par rayonnement terahertz. Les cas de nanofils de silicium non intentionnellement dopes et dopes type n sont compares pour differentes configurations du montage experimental. Les mesures de spectroscopie terahertz en transmission montre qu'il est possible de detecter la presence de dopants dans les nanofils via leur absorption du rayonnement terahertz (˜ 1--12 meV). Les difficultes de modelisation de la transmission d'une impulsion electromagnetique dans un systeme de nanofils sont egalement discutees. La detection differentielle, une modification au systeme de spectroscopie terahertz, est testee et ses performances sont comparees au montage de caracterisation standard. Les instructions et des recommendations pour la mise en place de ce type de mesure sont incluses. Les resultats d'une experience de pompe optique-sonde terahertz sont egalement presentes. Dans cette experience, les porteurs de charge temporairement crees suite a l'absorption de la pompe optique (lambda ˜ 800 nm) dans les nanofils (les photoporteurs) s'ajoutent aux porteurs initialement presents et augmentent done l'absorption du rayonnement terahertz. Premierement, l'anisotropie de l'absorption terahertz et de la pompe optique par les nanofils est demontree. Deuxiemement, le temps de recombinaison des photoporteurs est etudie en fonction du nombre de photoporteurs injectes. Une hypothese expliquant les comportements observes pour les nanofils non-dopes et dopes-n est presentee. Troisiemement, la photoconductivite est extraite pour les nanofils non-dopes et dopes-n sur une plage de 0.5 a 2 THz. Un lissage sur la photoconductivite permet d'estimer le nombre de dopants dans les nanofils dopes-n. Mots-cles: nanofil, silicium, terahertz, conductivite, spectroscopie, photoconductivite.

Light distribution in plant canopies: A comparison between 1-D multi-layer modeling approach and 3-D ray tracing

NASA Astrophysics Data System (ADS)

Srinivasan, V.; Yiwen, X.; Ellis, A.; Christensen, A.; Borkiewic, K.; Cox, D.; Hart, J.; Long, S.; Marshall-Colon, A.

2016-12-01

The distribution of absorbed solar radiation in the photosynthetically active region wavelength (PAR) within plant canopies plays a critical role in determining photosynthetic carbon uptake and its associated transpiration. The vertical distribution of leaf area, leaf angles, leaf absorptivity and reflectivity within the canopy, affect the distribution of PAR absorbed throughout the canopy. While the upper canopy sunlit leaves absorb most of the incoming PAR and hence contribute most towards total canopy carbon uptake, the lower canopy shaded leaves which receive mostly lower intensity diffuse PAR make significant contributions towards plant carbon uptake. Most detailed vegetation models use a 1-D vertical multi-layer approach to model the sunlight and shaded canopy leaf fractions, and quantify the direct and diffuse radiation absorbed by the respective leaf fractions. However, this approach is only applicable under canopy closure conditions, and furthermore it fails to accurately capture the effects of diurnally varying leaf angle distributions in some plant canopies. Here, we show by using a 3-D ray tracing model which uses an explicit 3-D canopy structure that enforces no conditions about canopy closure, that the effects of diurnal variation of canopy leaf angle distributions better match with observed data. Our comparative analysis performed on soybean crop canopies between 3-D ray tracing model and the multi-layer model shows that the distribution of absorbed direct PAR is not exponential while, the distribution of absorbed diffuse PAR radiation within plant canopies is exponential. These results show the multi-layer model to significantly over-predict canopy PAR absorbed, and in turn significantly overestimate photosynthetic carbon uptake by up to 13% and canopy transpiration by 7% under mid-day sun conditions as verified through our canopy chamber experiments. Our results indicate that current detailed 1-D multi-layer canopy radiation attenuation models significantly over predict canopy radiation absorption and its associated canopy photosynthetic and transpiration fluxes, and use of a 3-D ray tracing model provides more realistic predictions of leaf canopy integrated fluxes of carbon and water.

Cleavage of the urokinase receptor (uPAR) on oral cancer cells: regulation by transforming growth factor - β1 (TGF-β1) and potential effects on migration and invasion.

PubMed

Magnussen, Synnove Norvoll; Hadler-Olsen, Elin; Costea, Daniela Elena; Berg, Eli; Jacobsen, Cristiane Cavalcanti; Mortensen, Bente; Salo, Tuula; Martinez-Zubiaurre, Inigo; Winberg, Jan-Olof; Uhlin-Hansen, Lars; Svineng, Gunbjorg

2017-05-19

Urokinase plasminogen activator (uPA) receptor (uPAR) is up-regulated at the invasive tumour front of human oral squamous cell carcinoma (OSCC), indicating a role for uPAR in tumour progression. We previously observed elevated expression of uPAR at the tumour-stroma interface in a mouse model for OSCC, which was associated with increased proteolytic activity. The tumour microenvironment regulated uPAR expression, as well as its glycosylation and cleavage. Both full-length- and cleaved uPAR (uPAR (II-III)) are involved in highly regulated processes such as cell signalling, proliferation, migration, stem cell mobilization and invasion. The aim of the current study was to analyse tumour associated factors and their effect on uPAR cleavage, and the potential implications for cell proliferation, migration and invasion. Mouse uPAR was stably overexpressed in the mouse OSCC cell line AT84. The ratio of full-length versus cleaved uPAR as analysed by Western blotting and its regulation was assessed by addition of different protease inhibitors and transforming growth factor - β1 (TGF-β1). The role of uPAR cleavage in cell proliferation and migration was analysed using real-time cell analysis and invasion was assessed using the myoma invasion model. We found that when uPAR was overexpressed a proportion of the receptor was cleaved, thus the cells presented both full-length uPAR and uPAR (II-III). Cleavage was mainly performed by serine proteases and urokinase plasminogen activator (uPA) in particular. When the OSCC cells were stimulated with TGF-β1, the production of the uPA inhibitor PAI-1 was increased, resulting in a reduction of uPAR cleavage. By inhibiting cleavage of uPAR, cell migration was reduced, and by inhibiting uPA activity, invasion was reduced. We could also show that medium containing soluble uPAR (suPAR), and cleaved soluble uPAR (suPAR (II-III)), induced migration in OSCC cells with low endogenous levels of uPAR. These results show that soluble factors in the tumour microenvironment, such as TGF-β1, PAI-1 and uPA, can influence the ratio of full length and uPAR (II-III) and thereby potentially effect cell migration and invasion. Resolving how uPAR cleavage is controlled is therefore vital for understanding how OSCC progresses and potentially provides new targets for therapy.

Synthesis of Optode Thin Layer using Sol Gel Hybrid of Trietoxysiloxane monomer and 3-(Trimethoxysilyl) Propilamine with Ionophore 4-(2-Pyridilazo)-1,3-Benzenadiol (PAR)

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Rahmawati, F.; Kamal, S.; Slamet, S.; Yunianto, M.; Rahmawati, P.; Aini, F. N.

2018-03-01

Optode (Optical sensors) is one of the modern chemical sensors in the field of analytical chemistry that has utilized of inorganic polymers. The optode based on MLCT (Metal to Ligand Charge Transfer) (or MMLL’CT, Mixing Metal-Ligand to Ligand Charge Transfer) or LMCT (Ligand to Metal Charge Transfer) phenomenons have beed generated from oktyltrietxysilane, aminopropyltrimethoxysilane and 4-(2-pyrydilazo) resorcinol (abbreviated as OTES-APTS-PAR) for Cu(II), Cr(III), Ni(II), Fe(III), Cd(II), and Zn(II) ions target. The syntheses of thin layer optode were performed by sol gel method followed by evaporation in glass substrat. The formation of 4-(2-pyrydilazo) resorcinol complexes with ions target have gained strong absorption spectras in visible region because of charge transfer phenomenons. The optical sensor of OTES-APTS-PAR was analysed thermal properties using Differential Thermal Analysis (DTA). DTA thermogram showed a glass transition peaks at a temperature of 315.5 °C. Fourier transform Infrared (FTIR) spectras have showed that the optode materials consisted NH aryl groups indicated IR absorption at 1577.7 cm-1 and also –CH aromatic at 1469.0 cm-1. Synthesized optode materials have strong broad visible absorption with the maximum wavelengths (λmax) = 405 nm and 508.5 nm, respectively. This material have excellent optical responds to several metal ions such as Cu(II), Cr(III), Ni(II), Fe(III), Cd(II), and Zn(II) that was showed from huge Δλmax and the increase of Ktotal

Results of Several Years Experiments on the Absorption of Radioactive Strontium and Cesium by Cultivated Plants; COMPTE RENDU D'EXPERIENCES DE PLUSIEURS ANNEES SUR L'ABSORPTION DU STRONTIUM ET DU CESIUM RADIOACTIES PAR DES PLANTES CULTIVEES

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

Huguet, F. et al.

1962-01-01

The absorption of cesium-137 and strontium-90 by vines, permanent pasture, potatoes, green vegetables, tomatoes, onions, cabbage, and beans in France in 1960 is presented. The strontium coefficient has varied very little from one year to the next and that of cesium has slightly diminished. The values obtained suggest that the concentrations in irrigation water should not exceed one fifth of the maximum permissible concentration in drinking water. (auth)

Black Sea spectral bio-optical models based on satellite data and their applications for assessment of spatial and temporal variability in waters transparency, chlorophyll a content and primary production

NASA Astrophysics Data System (ADS)

Churilova, T.; Suslin, V.

2012-04-01

Satellite observations of ocean color provide a unique opportunity in oceanography to assess productivity of the sea on different spatial and temporal scales. However it has been shown that the standard SeaWiFS algorithm generally overestimates summer chlorophyll concentration and underestimates pigment content during spring phytoplankton bloom in comparison with in situ measurements. It is required to develop regional algorithms which are based on biooptical characteristics typical for the Sea and consequently could be used for correct transformation of spectral features of water-leaving radiance to chlorophyll a concentrations (Chl), light absorption features of suspended and dissolved organic matter (CDM), downwelling light attenuation coefficient/euphotic zone depth (PAR1%) and rate of primary synthesis of organic substances (PP). The numerous measurements of light absorption spectra of phytoplankton, non-algal particles and coloured dissolved organic matter carried out since 1996 in different seasons and regions of the Black Sea allowed to make a parameterization of the light absorption by all optically active components. Taking into account regional peculiarities of the biooptical parameters, their difference between seasons, shallow and deep-waters, their depth-dependent variability within photosynthetic zone regional spectral models for estimation of chlorophyll a concentration (Chl Model), colored dissolved and suspended organic matter absorption (CDM Model), downwelling irradiance (PAR Model) and primary production (PP Model) have been developed based on satellite data. Test of validation of models showed appropriate accuracy of the models. The developed models have been applied for estimation of spatial/temporal variability of chlorophyll a, dissolved organic matter concentrations, waters transparency, euphotic zone depth and primary production based on SeaWiFS data. Two weeks averaged maps of spatial distribution of these parameters have been composed for period from 1998 to 2009 (most of them presented on site http://blackseacolor.com/browser3.html). Comparative analysis of long-term series (since 1998) of these parameters with subsurface water temperature (SST) and solar radiance of the sea surface (PAR-0m) revealed the key factors determining the seasonal and inter-annual variations of Chl, PAR1%, CDM, PP. The seasonal dynamics of these parameters were more pronounced compared with inter-annual variability. The later was related to climate effect. In deep-waters region relatively lower SST during cold winters were forcing more intensive winter-spring phytoplankton bloom. In north-western shelf inter-annual variability in river (Danube) run off, which was related to climate change as well, determined year-to-year changing in Chl, CDM, PAR1%, and PP.

Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer.

PubMed

Schreiber, Ulrich; Klughammer, Christof; Kolbowski, Jörg

2012-09-01

Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420-640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)(λ), with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)(λ) is defined for a quasi-dark reference state, thus differing from σ(PSII) used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)(λ) the PAR, in units of μmol quanta/(m(2) s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)(max) can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)(max) with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen-evolving complex.

Bacterial DNA segregation dynamics mediated by the polymerizing protein ParF.

PubMed

Barillà, Daniela; Rosenberg, Mark F; Nobbmann, Ulf; Hayes, Finbarr

2005-04-06

Prokaryotic DNA segregation most commonly involves members of the Walker-type ParA superfamily. Here we show that the ParF partition protein specified by the TP228 plasmid is a ParA ATPase that assembles into extensive filaments in vitro. Polymerization is potentiated by ATP binding and does not require nucleotide hydrolysis. Analysis of mutations in conserved residues of the Walker A motif established a functional coupling between filament dynamics and DNA partitioning. The partner partition protein ParG plays two separable roles in the ParF polymerization process. ParF is unrelated to prokaryotic polymerizing proteins of the actin or tubulin families, but is a homologue of the MinD cell division protein, which also assembles into filaments. The ultrastructures of the ParF and MinD polymers are remarkably similar. This points to an evolutionary parallel between DNA segregation and cytokinesis in prokaryotic cells, and reveals a potential molecular mechanism for plasmid and chromosome segregation mediated by the ubiquitous ParA-type proteins.

Bacterial DNA segregation dynamics mediated by the polymerizing protein ParF

PubMed Central

Barillà, Daniela; Rosenberg, Mark F; Nobbmann, Ulf; Hayes, Finbarr

2005-01-01

Prokaryotic DNA segregation most commonly involves members of the Walker-type ParA superfamily. Here we show that the ParF partition protein specified by the TP228 plasmid is a ParA ATPase that assembles into extensive filaments in vitro. Polymerization is potentiated by ATP binding and does not require nucleotide hydrolysis. Analysis of mutations in conserved residues of the Walker A motif established a functional coupling between filament dynamics and DNA partitioning. The partner partition protein ParG plays two separable roles in the ParF polymerization process. ParF is unrelated to prokaryotic polymerizing proteins of the actin or tubulin families, but is a homologue of the MinD cell division protein, which also assembles into filaments. The ultrastructures of the ParF and MinD polymers are remarkably similar. This points to an evolutionary parallel between DNA segregation and cytokinesis in prokaryotic cells, and reveals a potential molecular mechanism for plasmid and chromosome segregation mediated by the ubiquitous ParA-type proteins. PMID:15775965

The contribution of mycosporine-like amino acids, chromophoric dissolved organic matter and particles to the UV protection of sea-ice organisms in the Baltic Sea.

PubMed

Piiparinen, Jonna; Enberg, Sara; Rintala, Janne-Markus; Sommaruga, Ruben; Majaneva, Markus; Autio, Riitta; Vähätalo, Anssi V

2015-05-01

The effects of ultraviolet radiation (UVR) on the synthesis of mycosporine-like amino acids (MAAs) in sea-ice communities and on the other UV-absorption properties of sea ice were studied in a three-week long in situ experiment in the Gulf of Finland, Baltic Sea in March 2011. The untreated snow-covered ice and two snow-free ice treatments, one exposed to wavelengths > 400 nm (PAR) and the other to full solar spectrum (PAR + UVR), were analysed for MAAs and absorption coefficients of dissolved (aCDOM) and particulate (ap) fractions, the latter being further divided into non-algal (anap) and algal (aph) components. Our results showed that the diatom and dinoflagellate dominated sea-ice algal community responded to UVR down to 25-30 cm depth by increasing their MAA : chlorophyll-a ratio and by extending the composition of MAA pool from shinorine and palythine to porphyra-334 and an unknown compound with absorption peaks at ca. 335 and 360 nm. MAAs were the dominant absorbing components in algae in the top 10 cm of ice, and their contribution to total absorption became even more pronounced under UVR exposure. In addition to MAAs, the high absorption by chromophoric dissolved organic matter (CDOM) and by deposited atmospheric particles provided UV-protection for sea-ice organisms in the exposed ice. Efficient UV-protection will especially be of importance under the predicted future climate conditions with more frequent snow-free conditions.

Characterization, Analysis and Significance of Defects in Composite Materials. Conference Proceedings: Meeting of the Structures and Materials Panel (56th) held in London, England on 12-14 April 1983

DTIC Science & Technology

1983-07-01

directional glass fibre, uni-directional carbon fibre and woven glass fabrJ (two weave styles ) all impregnated with epoxy resin.’-- An expanding mandrel...son emballage etanche pour revenir a temperature ambiante avant utllisatlon, - absorption d’eau si le preimpregn§ a tie laisse trop longtemps en...g6n~ralement de petite taille laisses par inadvortance nor le lieu do drapoge peuvent no- sir, par 6lectricitri statique, me caller sur la face cachie

Protease‐activated receptor 4: from structure to function and back again

PubMed Central

French, Shauna L

2016-01-01

Protease‐activated receptors are a family of four GPCRs (PAR1–PAR4) with a number of unique attributes. Nearly two and a half decades after the discovery of the first PAR, an antagonist targeting this receptor has been approved for human use. The first‐in‐class PAR1 antagonist, vorapaxar, was approved for use in the USA in 2014 for the prevention of thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. These recent developments indicate the clinical potential of manipulating PAR function. While much work has been aimed at uncovering the function of PAR1 and, to a lesser extent, PAR2, comparatively little is known regarding the pharmacology and physiology of PAR3 and PAR4. Recent studies have begun to develop the pharmacological and genetic tools required to study PAR4 function in detail, and there is now emerging evidence for the function of PAR4 in disease settings. In this review, we detail the discovery, structure, pharmacology, physiological significance and therapeutic potential of PAR4. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein‐Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc PMID:26844674

Analyse de la dégradation thermique du Poly(éther imide)

NASA Astrophysics Data System (ADS)

Courvoisier, Emilie; Bicaba, Yoann; Colin, Xavier

2018-03-01

La dégradation thermique du PEI a été étudiée dans de larges intervalles de température (entre 180 et 250 °C) et de pression partielle d'oxygène (entre 0,21 et 50 bars). Tout d'abord, les mécanismes de vieillissement thermique ont été analysés et élucidés par spectroscopie IRTF et par calorimétrie différentielle (DSC) sur des films de PEI suffisamment minces (entre 10 et 60 μm d'épaisseur) pour s'affranchir totalement des effets de la diffusion d'oxygène. Comme attendu, et par analogie avec d'autres polymères aromatiques de structure chimique similaire, l'oxydation se produit préférentiellement sur les groupes méthyle de l'unité isopropylidène du motif bisphenol A, causant la disparition de leur bande d'absorption IR caractéristique à 2970 cm-1 et la croissance d'une nouvelle bande d'absorption IR centrée à 3350 cm-1 et attribuée aux groupes alcool. De plus, l'oxydation conduit successivement à une prédominance relative des coupures de chaîne (diminution de Tg) et de la réticulation (augmentation de Tg). Enfin, les conséquences de l'oxydation sur les propriétés élastiques ont été analysées et élucidées par micro-indentation sur des sections droites préalablement polies de plaquettes de PEI de 3 mm d'épaisseur. Cependant, l'augmentation du module d'Young dans la couche superficielle oxydée est principalement due à un vieillissement physique.

Evaluation of hydrogen absorption cells for observations of the planetary coronas

NASA Astrophysics Data System (ADS)

Kuwabara, M.; Taguchi, M.; Yoshioka, K.; Ishida, T.; de Oliveira, N.; Ito, K.; Kameda, S.; Suzuki, F.; Yoshikawa, I.

2018-02-01

Newly designed Lyman-alpha absorption cells for imaging hydrogen planetary corona were characterized using an ultra high resolution Fourier transform spectrometer installed on the DESIRS (Dichroïsme Et Spectroscopie par Interaction avec le Rayonnement Synchrotron) beamline of Synchrotron SOLEIL in France. The early absorption cell installed in the Japanese Mars orbiter NOZOMI launched in 1998 had not been sufficiently optimized due to its short development time. The new absorption cells are equipped with the ability to change various parameters, such as filament shape, applied power, H2 gas pressure, and geometrical configuration. We found that the optical thickness of the new absorption cell was ˜4 times higher than the earlier one at the center wavelength of Lyman-alpha absorption, by optimizing the condition to promote thermal dissociation of H2 molecules into two H atoms on a hot tungsten filament. The Doppler temperature of planetary coronas could be determined with an accuracy better than 100 K with the performance of the newly developed absorption cell.

Allergic sensitization enhances anion current responsiveness of murine trachea to PAR-2 activation.

PubMed

Rievaj, Juraj; Davidson, Courtney; Nadeem, Ahmed; Hollenberg, Morley; Duszyk, Marek; Vliagoftis, Harissios

2012-03-01

Protease-activated receptor 2 (PAR-2) is a G protein-coupled receptor possibly involved in the pathogenesis of asthma. PAR-2 also modulates ion transport in cultured epithelial cells, but these effects in native airways are controversial. The influence of allergic inflammation on PAR-2-induced changes in ion transport has received little attention. Here, we studied immediate changes in transepithelial short circuit current (I (sc)) induced by PAR-2 activation in the tracheas of naive and allergic mice. Activation of PAR-2 with an apically added activation peptide (AP) induced a small increase in I (sc), while a much larger increase was observed following basolateral AP addition. In ovalbumin-sensitized and -challenged animals used as a model of allergic airway inflammation, the effect of basolateral AP addition was enhanced. Responses to basolateral AP in both naive and allergic mice were not decreased by blocking sodium absorption with amiloride or CFTR function with CFTR(inh)172 but were reduced by the cyclooxygenase inhibitor indomethacin and largely blocked (>80%) by niflumic acid, a calcium-activated chloride channels' (CaCC) blocker. Allergic mice also showed an enhanced response to ATP and thapsigargin. There was no change in mRNA expression of Par-2 or of the chloride channels Ano1 (Tmem16a) and Bestrophin 2 in tracheas from allergic mice, while mRNA levels of Bestrophin 1 were increased. In conclusion, basolateral PAR-2 activation in the mouse airways led to increased anion secretion through apical CaCC, which was more pronounced in allergic animals. This could be a protective mechanism aimed at clearing allergens and defending against mucus plugging.

Potentiation of the P2X3 ATP receptor by PAR-2 in rat dorsal root ganglia neurons, through protein kinase-dependent mechanisms, contributes to inflammatory pain.

PubMed

Wang, Shenglan; Dai, Yi; Kobayashi, Kimiko; Zhu, Wanjun; Kogure, Yoko; Yamanaka, Hiroki; Wan, You; Zhang, Wensheng; Noguchi, Koichi

2012-08-01

Proinflammatory agents trypsin and mast cell tryptase cleave and activate protease-activated receptor-2 (PAR-2), which is expressed on sensory nerves and causes neurogenic inflammation. P2X3 is a subtype of the ionotropic receptors for adenosine 5'-triphosphate (ATP), and is mainly localized on nociceptors. Here, we show that a functional interaction of the PAR-2 and P2X3 in primary sensory neurons could contribute to inflammatory pain. PAR-2 activation increased the P2X3 currents evoked by α, β, methylene ATP in dorsal root ganglia (DRG) neurons. Application of inhibitors of either protein kinase C (PKC) or protein kinase A (PKA) suppressed this potentiation. Consistent with this, a PKC or PKA activator mimicked the PAR-2-mediated potentiation of P2X3 currents. In the in vitro phosphorylation experiments, application of a PAR-2 agonist failed to establish phosphorylation of the P2X3 either on the serine or the threonine site. In contrast, application of a PAR-2 agonist induced trafficking of the P2X3 from the cytoplasm to the plasma membrane. These findings indicate that PAR-2 agonists may potentiate the P2X3, and the mechanism of this potentiation is likely to be a result of translocation, but not phosphorylation. The functional interaction between P2X3 and PAR-2 was also confirmed by detection of the α, β, methylene-ATP-evoked extracellular signal-regulated kinases (ERK) activation, a marker of neuronal signal transduction in DRG neurons, and pain behavior. These results demonstrate a functional interaction of the protease signal with the ATP signal, and a novel mechanism through which protease released in response to tissue inflammation might trigger the sensation to pain through P2X3 activation. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Application of normalized spectra in resolving a challenging Orphenadrine and Paracetamol binary mixture

NASA Astrophysics Data System (ADS)

Yehia, Ali M.; Abd El-Rahman, Mohamed K.

2015-03-01

Normalized spectra have a great power in resolving spectral overlap of challenging Orphenadrine (ORP) and Paracetamol (PAR) binary mixture, four smart techniques utilizing the normalized spectra were used in this work, namely, amplitude modulation (AM), simultaneous area ratio subtraction (SARS), simultaneous derivative spectrophotometry (S1DD) and ratio H-point standard addition method (RHPSAM). In AM, peak amplitude at 221.6 nm of the division spectra was measured for both ORP and PAR determination, while in SARS, concentration of ORP was determined using the area under the curve from 215 nm to 222 nm of the regenerated ORP zero order absorption spectra, in S1DD, concentration of ORP was determined using the peak amplitude at 224 nm of the first derivative ratio spectra. PAR concentration was determined directly at 288 nm in the division spectra obtained during the manipulation steps in the previous three methods. The last RHPSAM is a dual wavelength method in which two calibrations were plotted at 216 nm and 226 nm. RH point is the intersection of the two calibration lines, where ORP and PAR concentrations were directly determined from coordinates of RH point. The proposed methods were applied successfully for the determination of ORP and PAR in their dosage form.

Increased photosynthesis compensates for shorter growing season in subarctic tundra - seven years of snow accumulation manipulations

NASA Astrophysics Data System (ADS)

Bosiö, Julia; Johansson, Margareta; Njuabe, Herbert; Christensen, Torben R.

2013-04-01

This study was initiated to analyze the effect of snow cover on photosynthesis and plant growth in subarctic mires underlain by permafrost. Due to their narrow environmental window these raised bogs, often referred to as palsa mires, are highly sensitive to climatic changes. In Fennoscandia palsa mires are currently subjected to climate related thawing and shift in vegetational and hydrological patterns. Yet, we know little of how these subarctic permafrost mires react and feed back to such changes. By using snow fences to hinder snow drift the accumulation of snow was increased in six plots (10x20 m) in a snow manipulation experiment on a subarctic permafrost mire in northern Sweden. The thicker snow pack prolongs the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season. By measuring incoming and reflected photosynthetic active radiation (PAR) we wanted to address the question whether the increased snow thickness and associated delay of the growing season start affected the absorbed PAR and the accumulated gross primary production (GPP) over the season. The reflected PAR was measured at twelve plots where six of the plots experienced increased snow accumulation (treatment), and remaining six plots were untreated (control). Minikin QT sensors with integrated data loggers logged incoming and reflected PAR hourly throughout the growing seasons of 2011 and 2012. In July - September 2010 PAR measurements were coupled with flux chamber measurements to assess GPP and light use efficiency of the plots. The increased accumulation of snow prolonged the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season in the treated plots. The end of the growing season was not affected by the snow manipulation. The delay of the growing season start and hence overall shortening of the growing season in the treatment plots was 18 days in 2011 and 3 days in 2012 in relation to control plots. Results show higher PAR absorption together with almost 50% higher light use efficiency in treatment plots compared with control plots. Estimations of GPP suggest that the loss in early season photosynthesis due to the shortening of the growing season in the treatment plots is well compensated for by the increased absorption of PAR and higher light use efficiency throughout the whole growing seasons. This compensation is likely to be explained by increased soil moisture and nutrient availability together with a shift in vegetation composition associated with the accelerated permafrost thaw in the treatment plots. In our presentation implications and possible feedbacks of the increased absorbed PAR and estimated change in GPP will be discussed.

Protease-Activated Receptor 4 Variant p.Tyr157Cys Reduces Platelet Functional Responses and Alters Receptor Trafficking.

PubMed

Norman, Jane E; Cunningham, Margaret R; Jones, Matthew L; Walker, Mary E; Westbury, Sarah K; Sessions, Richard B; Mundell, Stuart J; Mumford, Andrew D

2016-05-01

Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by F2RL3, which has abundant rare missense variants. We aimed to provide proof of principle that rare F2LR3 variants potentially affect platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms. We identified 6 rare F2RL3 missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cysteine substitution (Y157C) was predicted computationally to have the greatest effect on PAR4 structure. Y157C platelets from 3 cases showed reduced responses to PAR4-activating peptide and to α-thrombin compared with controls, but no reduction in responses to PAR1-activating peptide. Pretreatment with the PAR1 antagonist vorapaxar caused lower residual α-thrombin responses in Y157C platelets than in controls, indicating greater platelet inhibition. HEK293 cells transfected with a PAR4 Y157C expression construct had reduced PAR4 functional responses, unchanged total PAR4 expression but reduced surface expression. PAR4 Y157C was partially retained in the endoplasmic reticulum and displayed an expression pattern consistent with defective N-glycosylation. Mutagenesis of Y322, which is the putative hydrogen bond partner of Y157, also reduced PAR4 surface expression in HEK293 cells. Reduced PAR4 responses associated with Y157C result from aberrant anterograde surface receptor trafficking, in part, because of disrupted intramolecular hydrogen bonding. Characterization of PAR4 Y157C establishes that rare F2RL3 variants have the potential to markedly alter platelet PAR4 reactivity particularly after exposure to therapeutic PAR1 antagonists. © 2016 American Heart Association, Inc.

Vegetation Function and Physiology: Photosynthesis, Fluorescence and Non-photochemical Quenching (NPQ)

NASA Astrophysics Data System (ADS)

Zhang, Q.; Yao, T.

2017-12-01

Photosynthesis is a basic physiological function of vegetation that relies on PAR provided through photosynthetic pigments (mainly chlorophyll) for plant growth and biomass accumulation. Vegetation chlorophyll (chl) content and non-chlorophyll (non-chl) components vary with plant functional types (PFTs) and growing stages. The PAR absorbed by canopy chlorophyll (APARchl) is associated with photosynthesis (i.e., gross primary production, GPP) while the PAR absorbed by canopy non-chl components (APARnon-chl) is not associated with photosynthesis. Under non-optimal environmental conditions, vegetation is "stressed" and both photosynthesis (GPP) and light use efficiency are reduced, therefore, excess portions of APARchl are discarded as fluorescence or non-photochemical quenching (NPQ). The photochemical reflectance index (PRI) is a measurement related to NPQ. Both PRI and yield of solar induced chlorophyll fluorescence (SIFyield = SIF/APARchl) have been proposed as possible bio-indicators of LUEchl. We have successfully developed an algorithm to distinguish between chlorophyll and non-chl components of vegetation, and to retrieve fractional absorptions of PAR by chlorophyll (fAPARchl) and by non-chl components (fAPARnon-chl) with surface reflectance of MODIS bands 1 - 7. A method originally pioneered by Hanan et al. (2002) has been used to retrieve fAPAR for vegetation photosynthesis (fAPARPSN) at flux tower sites based on the light response curve of tower net ecosystem exchange (NEE) and incident PAR at low light intensity. We have also retrieved the PRI from MODIS data (bands 11 and 1) and have derived SIFyield with the Global Ozone Monitoring Experiment - 2 (GOME-2) SIF data. We find that fAPARPSN at flux tower sites matches well with site fAPARchl, and ratio fAPARnon-chl/fAPARchl varies largely. APARchl can explain >=78% variation in seasonal GPP . We disentangle the possible impact of fAPARchl on PRI from physiological stress response, disentangle the possible impact of APARchl on SIFyield from physiological stress response, and find that integrating three bio-parameters fAPARchl, PRI and SIFyield can explain >=87% variation in seasonal GPP . Therefore, quantifying fAPARchl, PRI and SIF has the best potential to monitor vegetation function and physiology.

Thrombin Receptors and Protease-Activated Receptor-2 in Human Placentation

PubMed Central

O’Brien, Peter J.; Koi, Hideki; Parry, Samuel; Brass, Lawrence F.; Strauss, Jerome F.; Wang, Li-Peng; Tomaszewski, John E.; Christenson, Lane K.

2003-01-01

Proteolysis of the thrombin receptor, protease activated receptor-1 (PAR1), may enhance normal and pathological cellular invasion, and indirect evidence suggests that activation of PAR1 expressed by invasive extravillous trophoblasts (EVTs) influences human placentation. Here we describe PAR1, PAR2, and PAR3 protein distribution in the developing human placenta and implicate PAR1 and PAR2 activation in functions central to EVT invasion. PAR1, PAR2, and PAR3 are expressed in cultured 8- to 13-week-old EVTs, and in situ in 18- to 20-week-old placental syncytiotrophoblasts and invasive trophoblasts. Thrombin, but not the PAR2 agonist peptide SLIGKV, inhibited proliferation in cultured EVTs, although both agonists stimulated phosphoinositide hydrolysis and EVT invasion through Matrigel barriers. Thrombin-induced phosphoinositide hydrolysis was completely inhibited and the thrombin effect on proliferation was prevented when PAR1 cleavage was first blocked with specific monoclonal antibodies, indicating that PAR1 is the predominant thrombin receptor on EVTs. Together these results support a role for PAR1, and potentially PAR2 and PAR3 in the invasive phase of human placentation. PMID:14507634

In vitro and in vivo inhibition of proangiogenic retinal phenotype by an antisense oligonucleotide downregulating uPAR expression.

PubMed

Lulli, Matteo; Cammalleri, Maurizio; Granucci, Irene; Witort, Ewa; Bono, Silvia; Di Gesualdo, Federico; Lupia, Antonella; Loffredo, Rosa; Casini, Giovanni; Dal Monte, Massimo; Capaccioli, Sergio

2017-08-26

Neoangiogenesis is the main pathogenic event involved in a variety of retinal diseases. It has been recently demonstrated that inhibiting the urokinase-type plasminogen activator receptor (uPAR) results in reduced angiogenesis in a mouse model of oxygen-induced retinopathy (OIR), establishing uPAR as a therapeutic target in proliferative retinopathies. Here, we evaluated in cultured human retinal endothelial cells (HRECs) and in OIR mice the potential of a specific antisense oligodeoxyribonucleotide (ASO) in blocking the synthesis of uPAR and in providing antiangiogenic effects. uPAR expression in HRECs was inhibited by lipofection with the phosphorotioated 5'-CGGCGGGTGACCCATGTG-3' ASO-uPAR, complementary to the initial translation site of uPAR mRNA. Inhibition of uPAR expression via ASO-uPAR was evaluated in HRECs by analyzing VEGF-induced tube formation and migration. In addition, the well-established and reproducible murine OIR model was used to induce retinal neovascularization in vivo. OIR mice were injected intraperitoneally with ASO-uPAR and retinopathy was evaluated considering the extent of the avascular area in the central retina and neovascular tuft formation. The ASO-uPAR specifically decreased uPAR mRNA and protein levels in HRECs and mitigated VEGF-induced tube formation and cell migration. Noteworthy, in OIR mice ASO-uPAR administration reduced both the avascular area and the formation of neovascular tufts. In conclusion, although the extrapolation of these experimental findings to the clinic is not straightforward, ASO-uPAR may be considered a potential therapeutic tool for treatment of proliferative retinal diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Techniques for measuring intercepted and absorbed PAR in corn canopies

NASA Technical Reports Server (NTRS)

Gallo, K. P.; Daughtry, C. S. T.

1984-01-01

The quantity of radiation potentially available for photosynthesis that is captured by the crop is best described as absorbed photosynthetically active radiation (PAR). Absorbed PAR (APAR) is the difference between descending and ascending fluxes. The four components of APAR were measured above and within two planting densities of corn (Zea mays L.) and several methods of measuring and estimating APAR were examined. A line quantum sensor that spatially averages the photosynthetic photon flux density provided a rapid and portable method of measuring APAR. PAR reflectance from the soil (Typic Argiaquoll) surface decreased from 10% to less than 1% of the incoming PAR as the canopy cover increased. PAR reflectance from the canopy decreased to less than 3% at maximum vegetative cover. Intercepted PAR (1 - transmitted PAR) generally overestimated absorbed PAR by less than 4% throughout most of the growing season. Thus intercepted PAR appears to be a reasonable estimate of absorbed PAR.

Light attenuation characteristics of glacially-fed lakes

NASA Astrophysics Data System (ADS)

Rose, Kevin C.; Hamilton, David P.; Williamson, Craig E.; McBride, Chris G.; Fischer, Janet M.; Olson, Mark H.; Saros, Jasmine E.; Allan, Mathew G.; Cabrol, Nathalie

2014-07-01

Transparency is a fundamental characteristic of aquatic ecosystems and is highly responsive to changes in climate and land use. The transparency of glacially-fed lakes may be a particularly sensitive sentinel characteristic of these changes. However, little is known about the relative contributions of glacial flour versus other factors affecting light attenuation in these lakes. We sampled 18 glacially-fed lakes in Chile, New Zealand, and the U.S. and Canadian Rocky Mountains to characterize how dissolved absorption, algal biomass (approximated by chlorophyll a), water, and glacial flour contributed to attenuation of ultraviolet radiation (UVR) and photosynthetically active radiation (PAR, 400-700 nm). Variation in attenuation across lakes was related to turbidity, which we used as a proxy for the concentration of glacial flour. Turbidity-specific diffuse attenuation coefficients increased with decreasing wavelength and distance from glaciers. Regional differences in turbidity-specific diffuse attenuation coefficients were observed in short UVR wavelengths (305 and 320 nm) but not at longer UVR wavelengths (380 nm) or PAR. Dissolved absorption coefficients, which are closely correlated with diffuse attenuation coefficients in most non-glacially-fed lakes, represented only about one quarter of diffuse attenuation coefficients in study lakes here, whereas glacial flour contributed about two thirds across UVR and PAR. Understanding the optical characteristics of substances that regulate light attenuation in glacially-fed lakes will help elucidate the signals that these systems provide of broader environmental changes and forecast the effects of climate change on these aquatic ecosystems.

Urokinase-receptor (u-PAR): an essential player in multiple games of cancer: a review on its role in tumor progression, invasion, metastasis, proliferation/dormancy, clinical outcome and minimal residual disease.

PubMed

Laufs, Stephanie; Schumacher, Jens; Allgayer, Heike

2006-08-01

The relevance of the u-PA system in mediating tumor-associated proteolysis, invasion and metastasis, amongst other phenomena associated with tumor progression, has been clearly demonstrated in diverse cancer entities. This review will update on the biological and clinical relevance of the urokinase-receptor (u-PAR). Specifically, the article focuses on the potential importance of u-PAR for the development of minimal residual disease in solid cancer, and in this context reviews the biological relevance of the u-PAR for tumor cell dormancy. Furthermore, transcriptional mechanisms regulating u-PAR in vitro and in vivo, and their potential clinical and therapeutic relevance in gastrointestinal cancers, are elucidated.

Analysis of photosynthetically active radiation under various sky conditions in Wuhan, Central China.

PubMed

Wang, Lunche; Gong, Wei; Lin, Aiwen; Hu, Bo

2014-10-01

Observations of photosynthetically active radiation (PAR) and global solar radiation (G) at Wuhan, Central China during 2005-2012 were first reported to investigate PAR variability at different time scales and its PAR fraction (F(p)) under different sky conditions. Both G irradiances (I(g)) and PAR irradiances (I(p)) showed similar seasonal features that peaked in values at noon during summer and reached their lower values in winter. F(p) reached higher values during either sunrise or sunset; lower values of F p appeared at local noon because of the absorption effects of water vapor and clouds on long-wave radiation. There was an inverse relationship between clearness index (K(t)) and F(p); the maximum I(p) decreased by 22.3 % (39.7 %) when sky conditions changed from overcast to cloudless in summer (winter); solar radiation was more affected by cloudiness than the seasonal variation in cloudy skies when compared with that in clear skies. The maximum daily PAR irradiation (R(p)) was 11.89 MJ m⁻² day⁻¹ with an annual average of 4.85 MJ m⁻² day⁻¹. F p was in the range of 29-61.5 % with annual daily average value being about 42 %. Meanwhile, hourly, daily, and monthly relationships between R p and G irradiation (R g) under different sky conditions were investigated. It was discovered that cloudy skies were the dominated sky condition in this region. Finally, a clear-sky PAR model was developed by analyzing the dependence of PAR irradiances on optical air mass under various sky conditions for the whole study period in Central China, which will lay foundations for ecological process study in the near future.

Protease-activated receptor-2 (PAR(2)) in human periodontitis.

PubMed

Holzhausen, M; Cortelli, J R; da Silva, V Araújo; Franco, G C Nobre; Cortelli, S Cavalca; Vergnolle, N

2010-09-01

No evidence for the role of protease-activated receptor-2 (PAR(2)) in human periodontal disease has been demonstrated so far. Thus, we sought to investigate the expression of PAR(2) mRNA in chronic periodontitis, and to examine whether its expression is related to the presence of PAR(2) potential activators. Microbiological and gingival crevicular fluid samples were collected from individuals with chronic periodontitis and control individuals, and the presence of neutrophil serine proteinase 3 (P3) and Porphyromonas gingivalis was evaluated. PAR(2) mRNA expression was higher (p < 0.001) in those with chronic periodontitis compared with control individuals, and it was statistically decreased (p = 0.0006) after periodontal treatment. Furthermore, those with chronic periodontitis presented higher (p < 0.05) levels of IL-1alpha, IL-6, IL-8, and TNF-alpha, total proteolytic activity, P. gingivalis prevalence, and P3mRNA expression compared with control individuals. We conclude that PAR(2) mRNA expression and its potential activators are elevated in human chronic periodontitis, therefore suggesting that PAR(2) may play a role in periodontal inflammation.

Factor Xa Mediates Calcium Flux in Endothelial Cells and is Potentiated by Igg From Patients With Lupus and/or Antiphospholipid Syndrome.

PubMed

Artim-Esen, Bahar; Smoktunowicz, Natalia; McDonnell, Thomas; Ripoll, Vera M; Pericleous, Charis; Mackie, Ian; Robinson, Eifion; Isenberg, David; Rahman, Anisur; Ioannou, Yiannis; Chambers, Rachel C; Giles, Ian

2017-09-07

Factor (F) Xa reactive IgG isolated from patients with antiphospholipid syndrome (APS) display higher avidity binding to FXa with greater coagulant effects compared to systemic lupus erythematosus (SLE) non APS IgG. FXa signalling via activation of protease-activated receptors (PAR) leads to increased intracellular calcium (Ca 2+ ). Therefore, we measured alterations in Ca 2+ levels in human umbilical vein endothelial cells (HUVEC) following FXa-mediated PAR activation and investigated whether FXa reactive IgG from patients with APS or SLE/APS- alter these responses. We observed concentration-dependent induction of Ca 2+ release by FXa that was potentiated by APS-IgG and SLE/APS- IgG compared to healthy control subjects' IgG, and FXa alone. APS-IgG and SLE/APS- IgG increased FXa mediated NFκB signalling and this effect was fully-retained in the affinity purified anti-FXa IgG sub-fraction. Antagonism of PAR-1 and PAR-2 reduced FXa-induced Ca 2+ release. Treatment with a specific FXa inhibitor, hydroxychloroquine or fluvastatin significantly reduced FXa-induced and IgG-potentiated Ca 2+ release. In conclusion, PAR-1 and PAR-2 are involved in FXa-mediated intracellular Ca 2+ release in HUVEC and FXa reactive IgG from patients with APS and/or SLE potentiate this effect. Further work is required to explore the potential use of IgG FXa reactivity as a novel biomarker to stratify treatment with FXa inhibitors in these patients.

Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

PubMed

Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

2018-02-14

Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

Removal of focal segmental glomerulosclerosis (FSGS) factor suPAR using CytoSorb.

PubMed

Schenk, Heiko; Müller-Deile, Janina; Schmitt, Roland; Bräsen, Jan Hinrich; Haller, Hermann; Schiffer, Mario

2017-12-01

Treatment of primary focal segmental glomerulosclerosis (FSGS) and its recurrence after kidney transplantation associated with rapid deterioration of kidney function remains to be challenging despite advances in immunosuppressive therapy. The presence of circulating factors has been postulated to be a pivotal player in the pathogenesis of FSGS, although suPAR and CLCF-1 have been identified as the most promising causative factors. The potential therapeutic effect of suPAR elimination in an FSGS patient using CytoSorb, a hemoadsorption device that gained attention in the cytokine elimination in septic patients, was studied. Efficiency of total plasma exchange to remove suPAR was determined. CytoSorb hemoadsorption caused a 27.33% reduction of the suPAR level in a single treatment, whereas total plasma exchange showed a suPAR level reduction of 25.12% (n = 3; 95% confidence interval, 0.2777-0.8090; P < 0.01), which may indicate therapeutic potential in the treatment of primary FSGS and its recurrence in a kidney transplant. © 2017 Wiley Periodicals, Inc.

A method for estimating the incident PAR on inclined surfaces

NASA Astrophysics Data System (ADS)

Xie, Xiaoping; Gao, Wei; Gao, Zhiqiang

2008-08-01

A new simple model has been developed that incorporates Digital Elevation Model (DEM) and Moderate Resolution Imaging Spectroradiometer (MODIS) products to produce incident photosynthetically active radiation (PAR) for tilted surface. The method is based on a simplification of the general radiative transfer equation, which considers five major processes of attenuation of solar radiation: 1) Rayleigh scattering, 2) absorption by ozone and water vapor, 3) aerosol scattering, 4) multiple reflectance between surface and atmosphere, and 5) three terrain factors: slope and aspect, isotropic sky view factor, and additional radiation by neighbor reflectance. A comparison of the model results with observational data from the Yucheng and Changbai Mountain sites of the Chinese Ecosystem Research Network (CERN) shows the correlation coefficient as 0.929 and 0.904, respectively. A comparison of the model results with the 2006 filed measured PAR in the Yucheng and Changbai sites shows the correlation coefficient as 0.929 and 0.904, respectively, and the average percent error as 10% and 15%, respectively.

Mid-infrared crystalline supermirrors with ultralow optical absorption (Conference Presentation)

NASA Astrophysics Data System (ADS)

Deutsch, Christoph; Cole, Garrett D.; Follman, David; Heu, Paula; Bjork, Bryce J.; Franz, Chris; Alexandrovski, Alexei L.; Heckl, Oliver H.; Ye, Jun; Aspelmeyer, Markus

2017-02-01

Substrate-transferred crystalline coatings are a groundbreaking new concept for the fabrication of ultralow-loss mirrors. The single-crystal lattice structure of these substrate-transferred GaAs/AlGaAs Bragg mirrors exhibits the lowest mechanical losses and hence unmatched Brownian noise performance, which nowadays limits the stability of precision optical interferometers. Another outstanding feature of these coatings is the wide spectral coverage of the GaAs/AlGaAs material platform. Limited by interband absorption at short wavelengths and the reststrahlen band at long wavelengths, crystalline coatings can be employed as low-loss multilayers from approximately 900 nm up to 5 μm and beyond. Excellent optical performance has been demonstrated in the near-infrared with excess optical losses (scatter + absorption) as low as 3 parts per million (ppm), enabling cavity finesse values up to 360,000 at 1.55 μm. Our first attempts at applying crystalline coatings in the mid-infrared has resulted in mirrors with excess optical losses of 159 and 242 ppm at 3.3 and 3.7 μm, respectively. Remarkably, these results are already on par with current state-of-the-art amorphous mirror coatings. Absorption measurements based on photothermal common-path interferometry (PCI) reveal that the optical losses are largely dominated by optical scatter. Via, PCI, we have confirmed absorption losses below 10 ppm at 3.7 μm, showing the enormous potential of GaAs/AlGaAs Bragg mirrors at mid-infrared wavelengths. An optimized fabrication process, which is currently under development, can efficiently suppress optical scatter due to accumulated growth defects on the surface. Ultimately, we foresee excess losses significantly less than 50 ppm in the mid-infrared spectral region.

Non-hematopoietic PAR-2 is essential for matriptase-driven pre-malignant progression and potentiation of ras-mediated squamous cell carcinogenesis

PubMed Central

Sales, Katiuchia Uzzun; Friis, Stine; Konkel, Joanne E.; Godiksen, Sine; Hatakeyama, Marcia; Hansen, Karina K.; Rogatto, Silvia Regina; Szabo, Roman; Vogel, Lotte K.; Chen, Wanjun; Gutkind, J. Silvio; Bugge, Thomas H.

2014-01-01

The membrane-anchored serine protease, matriptase, is consistently dysregulated in a range of human carcinomas, and high matriptase activity correlates with poor prognosis. Furthermore, matriptase is unique among tumor-associated proteases in that epithelial stem cell expression of the protease suffices to induce malignant transformation. Here, we use genetic epistasis analysis to identify proteinase-activated receptor (PAR)-2-dependent inflammatory signaling as an essential component of matriptase-mediated oncogenesis. In cell-based assays, matriptase was a potent activator of PAR-2, and PAR-2 activation by matriptase caused robust induction of NFκB through Gαi. Importantly, genetic elimination of PAR-2 from mice completely prevented matriptase-induced pre-malignant progression, including inflammatory cytokine production, inflammatory cell recruitment, epidermal hyperplasia, and dermal fibrosis. Selective ablation of PAR-2 from bone marrow-derived cells did not prevent matriptase-driven pre-malignant progression, indicating that matriptase activates keratinocyte stem cell PAR-2 to elicit its pro-inflammatory and pro-tumorigenic effects. When combined with previous studies, our data suggest that dual induction of PAR-2-NFκB inflammatory signaling and PI3K-Akt-mTor survival/proliferative signaling underlies the transforming potential of matriptase and may contribute to pro-tumorigenic signaling in human epithelial carcinogenesis. PMID:24469043

Non-hematopoietic PAR-2 is essential for matriptase-driven pre-malignant progression and potentiation of ras-mediated squamous cell carcinogenesis.

PubMed

Sales, K U; Friis, S; Konkel, J E; Godiksen, S; Hatakeyama, M; Hansen, K K; Rogatto, S R; Szabo, R; Vogel, L K; Chen, W; Gutkind, J S; Bugge, T H

2015-01-15

The membrane-anchored serine protease, matriptase, is consistently dysregulated in a range of human carcinomas, and high matriptase activity correlates with poor prognosis. Furthermore, matriptase is unique among tumor-associated proteases in that epithelial stem cell expression of the protease suffices to induce malignant transformation. Here, we use genetic epistasis analysis to identify proteinase-activated receptor (PAR)-2-dependent inflammatory signaling as an essential component of matriptase-mediated oncogenesis. In cell-based assays, matriptase was a potent activator of PAR-2, and PAR-2 activation by matriptase caused robust induction of nuclear factor (NF)κB through Gαi. Importantly, genetic elimination of PAR-2 from mice completely prevented matriptase-induced pre-malignant progression, including inflammatory cytokine production, inflammatory cell recruitment, epidermal hyperplasia and dermal fibrosis. Selective ablation of PAR-2 from bone marrow-derived cells did not prevent matriptase-driven pre-malignant progression, indicating that matriptase activates keratinocyte stem cell PAR-2 to elicit its pro-inflammatory and pro-tumorigenic effects. When combined with previous studies, our data suggest that dual induction of PAR-2-NFκB inflammatory signaling and PI3K-Akt-mTor survival/proliferative signaling underlies the transforming potential of matriptase and may contribute to pro-tumorigenic signaling in human epithelial carcinogenesis.

Protease activated receptor 2 in diabetic nephropathy: a double edged sword

PubMed Central

Waasdorp, Maaike; Duitman, JanWillem; Florquin, Sandrine; Spek, Arnold C

2017-01-01

Diabetic nephropathy is a major microvascular complication of diabetes mellitus, and the leading cause of end stage renal disease worldwide. The pathogenesis of diabetic nephropathy is complex, making the development of novel treatments that stop or reverse the progression of microalbuminuria into end stage renal disease a challenge. Protease activated receptor (PAR)-2 has recently been shown to aggravate disease progression in diabetic nephropathy based upon which it was suggested that PAR-2 would be a potential target for the treatment of diabetic nephropathy. To fully appreciate the translational potential of PAR-2 in diabetic nephropathy, we evaluated the effect of PAR-2 deficiency on the development of diabetic nephropathy in a streptozotocin-induced diabetes model characteristic of type 1 diabetes. Although diabetic PAR-2 deficient mice showed reduced albuminuria compared to diabetic wild type mice, an increase in mesangial expansion was evident in the PAR-2 deficient mice. No differences were observed in blood glucose levels, podocyte numbers or in glomerular vascular density. These results show that PAR-2 plays a dual role in the development of streptozotocin-induced diabetic nephropathy and may thus not be the eagerly awaited novel target to combat diabetic nephropathy. Targeting PAR-2 should consequently only be pursued with great care in a clinical setting. PMID:29118913

Proteinase-Activated Receptor 1 (PAR1) Regulates Leukemic Stem Cell Functions

PubMed Central

Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E.

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1−/− hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1−/− leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance. PMID:24740120

Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

PubMed

Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Tryptase potentiates enteric nerve activation by histamine and serotonin: Relevance for the effects of mucosal biopsy supernatants from irritable bowel syndrome patients.

PubMed

Ostertag, D; Annahazi, A; Krueger, D; Michel, K; Demir, I E; Ceyhan, G O; Zeller, F; Schemann, M

2017-09-01

We previously showed that mucosal biopsy supernatants from irritable bowel syndrome patients activated neurons despite low concentrations of tryptase, histamine, and serotonin which individually would not cause spike discharge. We studied the potentiating responses between these mediators on excitability of enteric neurons. Calcium-imaging was performed using the calcium-sensitive dye Fluo-4 AM in human submucous plexus preparations from 45 individuals. Histamine, serotonin, and tryptase were applied alone and in combinations to evaluate nerve activation which was assessed by analyzing increase in intracellular Ca 2+ ([Ca 2+ ] i ), the proportion of responding neurons and the product of both defined as Ca-neuroindex (NI). Protease activated receptor (PAR) 2 activating peptide, PAR2 antagonist and the serine protease-inhibitor FUT-175 were used to particularly investigate the role of proteases. Histamine or serotonin (1 μmol/L each) evoked only few small responses (median NI [25%/75%]: 0 [0/148]; 85 [0/705] respectively). Their combined application evoked statistically similar responses (216 [21/651]). Addition of the PAR2 activator tryptase induced a significantly higher Ca-NI (1401 [867/4075]) compared to individual application of tryptase or to coapplied histamine and serotonin. This synergistic potentiation was neither mimicked by PAR2 activating peptide nor reversed by the PAR2 antagonist GB83, but abolished by FUT-175. We observed synergistic potentiation between histamine, serotonin, and tryptase in enteric neurons, which is mediated by proteolytic activity rather than PAR2 activation. This explained neuronal activation by a cocktail of these mediators despite their low concentrations and despite a relatively small PAR2-mediated response in human submucous neurons. © 2017 John Wiley & Sons Ltd.

Spectroscopie pompe-sonde pour la détection de bioaérosols

NASA Astrophysics Data System (ADS)

Guyon, L.; Courvoisier, F.; Wood, V.; Boutou, V.; Bartelt, A.; Roth, M.; Rabitz, H.; Wolf, J. P.

2006-10-01

La fluorescence du Tryptophane excité par une impulsion ultra-brève à 270 nm peut être diminuée d'un facteur deux par une seconde impulsion à 800 nm, à l'aide d'un dispositif pompe-sonde. Cette décroissance est aussi observée pour les bactéries vivantes, dont le Tryptophane est l'un des fluorophores, tandis qu'aucune décroissance n'est observée pour d'autres molécules organiques comme le naphtalène ou le gazole, malgré des spectres d'absorption et de fluorescence similaires. Cette différence remarquable est très prometteuse pour la distinction d'aérosols biologiques et organiques.

Blockade of protease-activated receptor-4 (PAR4) provides robust antithrombotic activity with low bleeding.

PubMed

Wong, Pancras C; Seiffert, Dietmar; Bird, J Eileen; Watson, Carol A; Bostwick, Jeffrey S; Giancarli, Mary; Allegretto, Nick; Hua, Ji; Harden, David; Guay, Jocelyne; Callejo, Mario; Miller, Michael M; Lawrence, R Michael; Banville, Jacques; Guy, Julia; Maxwell, Brad D; Priestley, E Scott; Marinier, Anne; Wexler, Ruth R; Bouvier, Michel; Gordon, David A; Schumacher, William A; Yang, Jing

2017-01-04

Antiplatelet agents are proven efficacious treatments for cardiovascular and cerebrovascular diseases. However, the existing drugs are compromised by unwanted and sometimes life-threatening bleeding that limits drug usage or dosage. There is a substantial unmet medical need for an antiplatelet drug with strong efficacy and low bleeding risk. Thrombin is a potent platelet agonist that directly induces platelet activation via the G protein (heterotrimeric guanine nucleotide-binding protein)-coupled protease-activated receptors PAR1 and PAR4. A PAR1 antagonist is approved for clinical use, but its use is limited by a substantial bleeding risk. Conversely, the potential of PAR4 as an antiplatelet target has not been well characterized. Using anti-PAR4 antibodies, we demonstrated a low bleeding risk and an effective antithrombotic profile with PAR4 inhibition in guinea pigs. Subsequently, high-throughput screening and an extensive medicinal chemistry effort resulted in the discovery of BMS-986120, an orally active, selective, and reversible PAR4 antagonist. In a cynomolgus monkey arterial thrombosis model, BMS-986120 demonstrated potent and highly efficacious antithrombotic activity. BMS-986120 also exhibited a low bleeding liability and a markedly wider therapeutic window compared to the standard antiplatelet agent clopidogrel tested in the same nonhuman primate model. These preclinical findings define the biological role of PAR4 in mediating platelet aggregation. In addition, they indicate that targeting PAR4 is an attractive antiplatelet strategy with the potential to treat patients at a high risk of atherothrombosis with superior safety compared with the current standard of care. Copyright © 2017, American Association for the Advancement of Science.

The Impact of Atmospheric Aerosols on the Fraction of absorbed Photosynthetically Active Radiation

NASA Astrophysics Data System (ADS)

Veroustraete, Frank

2010-05-01

Aerosol pollution attracts a growing interest from atmospheric scientists with regard to their impact on health, the global climate and vegetation stress. A hypothesis, less investigated, is whether atmospheric aerosol interactions in the solar radiation field affect the amount of radiation absorbed by vegetation canopies and hence terrestrial vegetation productivity. Typically, aerosols affect vegetation canopy radiation absorption efficiency by altering the physical characteristics of solar radiation incoming on for example a forest canopy. It has been illustrated, that increasing mixing ratio's of atmospheric particulate matter lead to a higher fraction of diffuse sunlight as opposed to direct sunlight. It can be demonstrated, based on the application of atmospheric (MODTRAN) and leaf/canopy radiative transfer (LIBERTY/SPRINT) models, that radiation absorption efficiency in the PAR band of Picea like forests increases with increasing levels of diffuse radiation. It can be documented - on a theoretical basis - as well, that increasing aerosol loads in the atmosphere, induce and increased canopy PAR absorption efficiency. In this paper it is suggested, that atmospheric aerosols have to be taken into account when estimating vegetation gross primary productivity (GPP). The results suggest that Northern hemisphere vegetation CO2 uptake magnitude may increase with increasing atmospheric aerosol loads. Many climate impact scenario's related to vegetation productivity estimates, do not take this phenomenon into account. Boldly speaking, the results suggest a larger sink function for terrestrial vegetation than generally accepted. Keywords: Aerosols, vegetation, fAPAR, CO2 uptake, diffuse radiation.

Mesures spectroscopiques de constituants et de polluants atmosphériques par techniques in situ et à distance, au sol ou embarquéesSpectroscopic measurements of atmospheric constituents and pollutants by in situ and remote techniques from the ground and in flight

NASA Astrophysics Data System (ADS)

Camy-Peyret, Claude; Payan, Sébastien; Jeseck, Pascal; Té, Yao

2001-09-01

Infrared spectroscopy is a powerful tool for precise measurements of atmospheric trace species concentrations through the use of characteristic spectral signatures of the different molecular species and their associated vibration-rotation bands in the mid- or near-infrared. Different methods based on quantitative spectroscopy permit tropospheric or stratospheric measurements: in situ long path absorption, atmospheric absorption/emission by Fourier transform spectroscopy with high spectral resolution instruments on the ground, airborne, balloon-borne or satellite-borne.

Photochemistry of transition-metal phthalocyanines. Analysis of the photochemical and photophysical properties of the acido(phthalocyaninato)rhodium(III) complexes

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

Ferraudi, G.; Muralidharan, S.

1983-04-01

The ultraviolet photochemistry of the rhodium(II) phthalocyanines Rh(ph)(CH/sub 3/OH)X with X = Cl/sup -/, Br/sup -/, and I/sup -/ was investigated at different wavelengths. The same action spectrum for the photoinduced hydrogen abstraction was obtained for the three compounds. The photonic energy of the excitation is degraded in part by emission at short wavelengths, e.g. lambda/sub max/ approx. = 420 nm. Such a violet emission, observed with phthalocyanines of Al(III), Rh(III), Co(III), and Ru(II), has been attributed to the relaxation of an upper /sup 3/par. deltapar. delta* excited state. The emissions spectra at 77 K exhibited vibronic components with amore » separation between successive peaks ..delta nu.. approx. = 1.3 x 10/sup 3/ cm/sup -1/. A comparison between the excitation and action spectra shows the difference in the paths that populate the reactive npar. delta* and upper emissive par. deltapar. delta* states. An investigation of the time dependence of the upper /sup 3/par. deltapar. delta* emission and lowest /sup 3/par. deltapar. delta* absorptions reveals the participation of triplet sublevels in the degradation of the excitation energy. The relationship between photoemissive and photoreactive states is discussed.« less

Influence of aerosol dry deposition on photosynthetically active radiation available to plants: A case study in the Yangtze Delta Region of China

NASA Astrophysics Data System (ADS)

Bergin, M. H.; Greenwald, R.; Xu, J.; Berta, Y.; Chameides, W. L.

In this paper, a new mechanism is proposed by which aerosols decrease the amount of photosynthetically active radiation (PAR) available to plants for photosynthesis. The mechanism involves the scattering and absorption of PAR by water insoluble aerosol particles (WIA) which deposit on leaves and are not washed off by precipitation. A simple model is developed that predicts the change in the transmittance of PAR, TPAR, for plant leaves due to WIA dry deposition as a function of aerosol chemical, physical, and optical properties. Model estimates for the agricultural Yangtze delta region of China indicate that over a 2-month period during a growing season, dry deposition of WIA may account for a ∼35% reduction in PAR available for plant photosynthesis. Although, the estimate is sensitive to several factors that are uncertain including aerosol dry deposition velocity, leaf area index, and removal rate of particles by precipitation. Results suggest that impacts on crop yields due to aerosol dry deposition could be considerable in this region and suggest a previously neglected economic incentive for China to mitigate air pollution. Additionally, WIA dry deposition may influence carbon uptake by plants in other locations that experience regional haze.

Astrocytes Secrete Exosomes Enriched with Proapoptotic Ceramide and Prostate Apoptosis Response 4 (PAR-4)

PubMed Central

Wang, Guanghu; Dinkins, Michael; He, Qian; Zhu, Gu; Poirier, Christophe; Campbell, Andrew; Mayer-Proschel, Margot; Bieberich, Erhard

2012-01-01

Amyloid protein is well known to induce neuronal cell death, whereas only little is known about its effect on astrocytes. We found that amyloid peptides activated caspase 3 and induced apoptosis in primary cultured astrocytes, which was prevented by caspase 3 inhibition. Apoptosis was also prevented by shRNA-mediated down-regulation of PAR-4, a protein sensitizing cells to the sphingolipid ceramide. Consistent with a potentially proapoptotic effect of PAR-4 and ceramide, astrocytes surrounding amyloid plaques in brain sections of the 5xFAD mouse (and Alzheimer disease patient brain) showed caspase 3 activation and were apoptotic when co-expressing PAR-4 and ceramide. Apoptosis was not observed in astrocytes with deficient neutral sphingomyelinase 2 (nSMase2), indicating that ceramide generated by nSMase2 is critical for amyloid-induced apoptosis. Antibodies against PAR-4 and ceramide prevented amyloid-induced apoptosis in vitro and in vivo, suggesting that apoptosis was mediated by exogenous PAR-4 and ceramide, potentially associated with secreted lipid vesicles. This was confirmed by the analysis of lipid vesicles from conditioned medium showing that amyloid peptide induced the secretion of PAR-4 and C18 ceramide-enriched exosomes. Exosomes were not secreted by nSMase2-deficient astrocytes, indicating that ceramide generated by nSMase2 is critical for exosome secretion. Consistent with the ceramide composition in amyloid-induced exosomes, exogenously added C18 ceramide restored PAR-4-containing exosome secretion in nSMase2-deficient astrocytes. Moreover, isolated PAR-4/ceramide-enriched exosomes were taken up by astrocytes and induced apoptosis in the absence of amyloid peptide. Taken together, we report a novel mechanism of apoptosis induction by PAR-4/ceramide-enriched exosomes, which may critically contribute to Alzheimer disease. PMID:22532571

Lesioning of TRPV1 expressing primary afferent neurons prevents PAR-2 induced motility, but not mechanical hypersensitivity in the rat colon.

PubMed

Suckow, S K; Anderson, E M; Caudle, R M

2012-03-01

Proteinase activated receptor 2 (PAR-2) is expressed by many neurons in the colon, including primary afferent neurons that co-express transient receptor potential vanilloid 1 (TRPV1). Activation of PAR-2 receptors was previously found to enhance colonic motility, increase secretion and produce hypersensitivity to mechanical stimuli. This study examined the functional role of TRPV1/PAR-2 expressing neurons that innervate the colon by lesioning TRPV1 bearing neurons with the highly selective and potent TRPV1 agonist resiniferatoxin. Colonic motility in response to PAR-2 activation was evaluated in vitro using isolated segments of descending colon and in vivo using manometry. Colonic mechanical nociceptive thresholds were measured using colorectal distension. Transient receptor potential vanilloid 1 expressing neurons were selectively lesioned with resiniferatoxin. In vitro, the PAR-2 agonists, trypsin and SLIGRL did not alter contractions of colon segments when applied alone, however, the agents enhanced acetylcholine stimulated contraction. In vivo, PAR-2 agonists administered intraluminally induced contractions of the colon and produced hypersensitivity to colorectal distention. The PAR-2 agonist enhancement of colonic contraction was eliminated when TRPV1 expressing neurons were lesioned with resiniferatoxin, but the PAR-2 agonist induced hypersensitivity remained in the lesioned animals. Our findings indicate that TRPV1/PAR-2 expressing primary afferent neurons mediate an extrinsic motor reflex pathway in the colon. These data, coupled with our previous studies, also indicate that the recently described colospinal afferent neurons are nociceptive, suggesting that these neurons may be useful targets for the pharmacological control of pain in diseases such as irritable bowel syndrome. © 2011 Blackwell Publishing Ltd.

The DNA binding parvulin Par17 is targeted to the mitochondrial matrix by a recently evolved prepeptide uniquely present in Hominidae

PubMed Central

Kessler, Daniel; Papatheodorou, Panagiotis; Stratmann, Tina; Dian, Elke Andrea; Hartmann-Fatu, Cristina; Rassow, Joachim; Bayer, Peter; Mueller, Jonathan Wolf

2007-01-01

Background The parvulin-type peptidyl prolyl cis/trans isomerase Par14 is highly conserved in all metazoans. The recently identified parvulin Par17 contains an additional N-terminal domain whose occurrence and function was the focus of the present study. Results Based on the observation that the human genome encodes Par17, but bovine and rodent genomes do not, Par17 exon sequences from 10 different primate species were cloned and sequenced. Par17 is encoded in the genomes of Hominidae species including humans, but is absent from other mammalian species. In contrast to Par14, endogenous Par17 was found in mitochondrial and membrane fractions of human cell lysates. Fluorescence of EGFP fusions of Par17, but not Par14, co-localized with mitochondrial staining. Par14 and Par17 associated with isolated human, rat and yeast mitochondria at low salt concentrations, but only the Par17 mitochondrial association was resistant to higher salt concentrations. Par17 was imported into mitochondria in a time and membrane potential-dependent manner, where it reached the mitochondrial matrix. Moreover, Par17 was shown to bind to double-stranded DNA under physiological salt conditions. Conclusion Taken together, the DNA binding parvulin Par17 is targeted to the mitochondrial matrix by the most recently evolved mitochondrial prepeptide known to date, thus adding a novel protein constituent to the mitochondrial proteome of Hominidae. PMID:17875217

Endophthalmitis following pars plana vitrectomy for vitreous floaters

PubMed Central

Henry, Christopher R; Schwartz, Stephen G; Flynn, Harry W

2014-01-01

A case of Staphylococcus caprae endophthalmitis in a young patient following pars plana vitrectomy for symptomatic vitreous floaters is reported here. Recent literature suggests that there is an increasing trend of performing pars plana vitrectomy for symptomatic floaters. Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters. PMID:25210434

Endophthalmitis following pars plana vitrectomy for vitreous floaters.

PubMed

Henry, Christopher R; Schwartz, Stephen G; Flynn, Harry W

2014-01-01

A case of Staphylococcus caprae endophthalmitis in a young patient following pars plana vitrectomy for symptomatic vitreous floaters is reported here. Recent literature suggests that there is an increasing trend of performing pars plana vitrectomy for symptomatic floaters. Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters.

IFN-γ, CXCL16, uPAR: potential biomarkers for systemic lupus erythematosus.

PubMed

Wen, Si; He, Fang; Zhu, Xuejing; Yuan, Shuguang; Liu, Hong; Sun, Lin

2018-01-01

IFN-γ, CXCL16 and uPAR have recently been regarded as potential biomarkers in systemic lupus erythematosus (SLE). However, few researches have focused on the comparison of these three markers in SLE. We conducted this study to evaluate their role as biomarkers of disease activity and renal damage. We enrolled 50 SLE patients with or without lupus nephritis (LN) and 15 healthy control subjects. The levels of IFN-γ, CXCL16, uPAR in serum, urine and renal tissues were detected by ELISA or immunohistochemistry. Relevant clinical and laboratory features were recorded. Serum and urine IFN-γ, CXCL16 and suPAR levels in SLE patients were significantly higher than that in healthy controls. Moreover, LN patients had higher levels than non-LN patients. A positive correlation was observed between these markers, and disease activity and suPAR had a stronger association with disease activity. The expression of these biomarkers in renal tissues was significantly higher in LN patients and was also associated with the activity of pathological lesions. IFN-γ, CXCL16 and uPAR are promising as effective biomarkers of disease activity, renal damage, and the activity of pathological lesions in SLE.

Involvement of nitric oxide synthase in matrix metalloproteinase-9- and/or urokinase plasminogen activator receptor-mediated glioma cell migration

PubMed Central

2013-01-01

Background Src tyrosine kinase activates inducible nitric oxide synthase (iNOS) and, in turn, nitric oxide production as a means to transduce cell migration. Src tyrosine kinase plays a key proximal role to control α9β1 signaling. Our recent studies have clearly demonstrated the role of α9β1 integrin in matrix metalloproteinase-9 (MMP-9) and/or urokinase plasminogen activator receptor (uPAR)-mediated glioma cell migration. In the present study, we evaluated the involvement of α9β1 integrin-iNOS pathway in MMP-9- and/or uPAR-mediated glioma cell migration. Methods MMP-9 and uPAR shRNAs and overexpressing plasmids were used to downregulate and upregulate these molecules, respectively in U251 glioma cells and 5310 glioma xenograft cells. The effect of treatments on migration and invasion potential of these glioma cells were assessed by spheroid migration, wound healing, and Matrigel invasion assays. In order to attain the other objectives we also performed immunocytochemical, immunohistochemical, RT-PCR, Western blot and fluorescence-activated cell sorting (FACS) analysis. Results Immunohistochemical analysis revealed the prominent association of iNOS with glioblastoma multiforme (GBM). Immunofluorescence analysis showed prominent expression of iNOS in glioma cells. MMP-9 and/or uPAR knockdown by respective shRNAs reduced iNOS expression in these glioma cells. RT-PCR analysis revealed elevated iNOS mRNA expression in either MMP-9 or uPAR overexpressed glioma cells. The migration potential of MMP-9- and/or uPAR-overexpressed U251 glioma cells was significantly inhibited after treatment with L-NAME, an inhibitor of iNOS. Similarly, a significant inhibition of the invasion potential of the control or MMP-9/uPAR-overexpressed glioma cells was noticed after L-NAME treatment. A prominent reduction of iNOS expression was observed in the tumor regions of nude mice brains, which were injected with 5310 glioma cells, after MMP-9 and/or uPAR knockdown. Protein expressions of cSrc, phosphoSrc and p130Cas were reduced with simultaneous knockdown of both MMP-9 and uPAR. Conclusions Taken together, our results from the present and earlier studies clearly demonstrate that α9β1 integrin-mediated cell migration utilizes the iNOS pathway, and inhibition of the migratory potential of glioma cells by simultaneous knockdown of MMP-9 and uPAR could be attributed to the reduced α9β1 integrin and iNOS levels. PMID:24325546

ZnO layers prepared by spray pyrolysis

NASA Astrophysics Data System (ADS)

Messaoudi, C.; Abd-Lefdil, S.; Sayah, D.; Cadene, M.

1998-02-01

Highly transparent undoped and indium doped ZnO thin films have been grown on glass substrates by using the spray pyrolysis process. Conditions of preparation have been optimized to get good quality and reproducible films with required properties. Polycrystalline films with an hexagonal Wurtzite-type structure were easily obtained under the optimum spraying conditions. Both of samples have shown high transmission coefficient in the visible and infrared wavelength range with sharp absorption edge around 380 nm which closely corresponds to the intrinsic band-gap of ZnO (3.2 eV). Orientation and crystallites size were remarkably modified by deposition temperature and indium doping. Des couches minces de ZnO, hautement transparentes, non dopées et dopées à l'indium ont été élaborées sur un substrat en verre par le procédé de pulvérisation chimique réactive spray. Les conditions de préparation ont été optimisées pour l'obtention de couches reproductibles, de bonne qualité et ayant les propriétés requises. Des films polycristallins, présentant une structure hexagonale de type Wurtzite, ont été aisément obtenus dans les conditions optimales de pulvérisation. Tous les échantillons ont présenté un coefficient de transmission élevé dans le domaine du visible et du proche infrarouge, avec une absorption brutale au voisinage de 380 nm, correspondant au gap optique du ZnO (3,2 eV). L'orientation et la taille des cristallites ont été remarquablement modifiées par la température du dépôt et par le dopage à l'indium.

MtPAR MYB transcription factor acts as an on switch for proanthocyanidin biosynthesis in Medicago truncatula

PubMed Central

Verdier, Jerome; Zhao, Jian; Torres-Jerez, Ivone; Ge, Shujun; Liu, Chenggang; He, Xianzhi; Mysore, Kirankumar S.; Dixon, Richard A.; Udvardi, Michael K.

2012-01-01

MtPAR (Medicago truncatula proanthocyanidin regulator) is an MYB family transcription factor that functions as a key regulator of proanthocyanidin (PA) biosynthesis in the model legume Medicago truncatula. MtPAR expression is confined to the seed coat, the site of PA accumulation. Loss-of-function par mutants contained substantially less PA in the seed coat than the wild type, whereas levels of anthocyanin and other specialized metabolites were normal in the mutants. In contrast, massive accumulation of PAs occurred when MtPAR was expressed ectopically in transformed hairy roots of Medicago. Transcriptome analysis of par mutants and MtPAR-expressing hairy roots, coupled with yeast one-hybrid analysis, revealed that MtPAR positively regulates genes encoding enzymes of the flavonoid–PA pathway via a probable activation of WD40-1. Expression of MtPAR in the forage legume alfalfa (Medicago sativa) resulted in detectable levels of PA in shoots, highlighting the potential of this gene for biotechnological strategies to increase PAs in forage legumes for reduction of pasture bloat in ruminant animals. PMID:22307644

Protease-activated receptor (PAR)2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

PubMed

van den Hengel, Lisa G; Hellingman, Alwine A; Nossent, Anne Yael; van Oeveren-Rietdijk, Annemarie M; de Vries, Margreet R; Spek, C Arnold; van Zonneveld, Anton Jan; Reitsma, Pieter H; Hamming, Jaap F; de Boer, Hetty C; Versteeg, Henri H; Quax, Paul H A

2013-01-01

In collateral development (i.e. arteriogenesis), mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR)1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. PAR1-deficient (PAR1-/-), PAR2-deficient (PAR2-/-) and wild-type (WT) mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA)-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low) monocytes and the number of repair-associated (CD206-positive) macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD) patients.

Differences in PAR-2 activating potential by king crab (Paralithodes camtschaticus), salmon (Salmo salar), and bovine (Bos taurus) trypsin.

PubMed

Larsen, Anett K; Kristiansen, Kurt; Sylte, Ingebrigt; Seternes, Ole-Morten; Bang, Berit E

2013-07-20

Salmon trypsin is shown to increase secretion of the pro-inflammatory cytokine interleukin (IL)-8 from human airway epithelial cells through activation of PAR-2. Secretion of IL-8 induced by king crab trypsin is observed in a different concentration range compared to salmon trypsin, and seems to be only partially related to PAR-2 activation. This report aim to identify differences in the molecular structure of king crab trypsin (Paralithodes camtschaticus) compared to salmon (Salmo salar) and bovine trypsin (Bos taurus) that might influence the ability to activate protease-activated receptor-2 (PAR-2). During purification king crab trypsin displayed stronger binding capacity to the anionic column used in fast protein liquid chromatography compared to fish trypsins, and was identified as a slightly bigger molecule. Measurements of enzymatic activity yielded no obvious differences between the trypsins tested. Molecular modelling showed that king crab trypsin has a large area with strong negative electrostatic potential compared to the smaller negative areas in bovine and salmon trypsins. Bovine and salmon trypsins also displayed areas with strong positive electrostatic potential, a feature lacking in the king crab trypsin. Furthermore we have identified 3 divergent positions (Asp196, Arg244, and Tyr247) located near the substrate binding pocket of king crab trypsin that might affect the binding and cleavage of PAR-2. These preliminary results indicate that electrostatic interactions could be of importance in binding, cleavage and subsequent activation of PAR-2.

Expression of proteinase-activated receptor (PAR)-2 in monocytes from allergic patients and potential molecular mechanism.

PubMed

Ge, Shuqing; Li, Tao; Yao, Qijian; Yan, Hongling; Huiyun, Zhang; Zheng, Yanshan; Zhang, Bin; He, Shaoheng

2016-12-01

Serine proteases play an important role in inflammation via PARs. However, little is known of expression levels of PARs on monocytes of allergic patients, and influence of serine proteases and PARs on TNF-α secretion from monocytes. Using quantitative real-time PCR (qPCR) and flowcytometry techniques, we observed that the expression level of PAR-2 in monocytes of patients with allergic rhinitis and asthma was increased by 42.9 and 38.2 %. It was found that trypsin, thrombin, and tryptase induced up to 200, 320, and 310 % increase in TNF-α release from monocytes at 16 h, respectively. PAR-1 agonist peptide, SFLLR-NH 2 , and PAR-2 agonist peptide tc-LIGRLO-NH 2 provoked up to 210 and 240 % increase in release of TNF-α. Since SCH 79797, a PAR-1 antagonist, and PD98059, an inhibitor of ERK inhibited thrombin- and SFLLR-NH 2 -induced TNF-α release, the action of thrombin is most likely through a PAR-1- and ERK-mediated signaling mechanism. Similarly, because FSLLRN-NH 2 , an inhibitor of PAR-2 diminished tryptase- and tc-LIGRLO-NH 2 -induced TNF-α release, the action of tryptase appears PAR-2 dependent. Moreover, in vivo study showed that both recombinant cockroach major allergens Per a 1 and Per a 7 provoked upregulation of PAR-2 and PAR-1 expression on CD14+ cells in OVA-sensitized mouse peritoneum. In conclusion, increased expression of PAR-2 in monocytes of AR and asthma implicates that PAR-2 likely play a role in allergy. PAR-2- and PAR-1-mediated TNF-α release from monocytes suggests that these unique protease receptors are involved in the pathogenesis of inflammation.

Inherent and apparent optical properties of the complex estuarine waters of Tampa Bay: What controls light?

NASA Astrophysics Data System (ADS)

Le, Chengfeng; Hu, Chuanmin; English, David; Cannizzaro, Jennifer; Chen, Zhiqiang; Kovach, Charles; Anastasiou, Christopher J.; Zhao, Jun; Carder, Kendall L.

2013-01-01

Inherent and apparent optical properties (IOPs and AOPs) of Tampa Bay (Florida, USA) were measured during fourteen cruises between February 1998 and October 2010 to understand how these properties relate to one another and what controls light absorption and diffuse attenuation in this moderately sized (˜1000 km2), shallow estuary (average depth ˜4 m). The IOPs and AOPs included: 1) absorption coefficients of three optically significant constituents: phytoplankton pigments, detrital particles, and colored dissolved organic matter (CDOM); 2) particulate backscattering coefficients; 3) chlorophyll-a concentrations; 4) above-water remote sensing reflectance; 5) downwelling diffuse attenuation coefficients (Kd) at eight wavelengths and photosynthetically active radiation (PAR). Results showed substantial variability in all IOPs and AOPs in both space and time, with most IOPs spanning more than two orders of magnitude and showing strong co-variations. Of all four bay segments, Old Tampa Bay showed unique optical characteristics. During the wet season, the magnitude of blue-green-light absorption was dominated by CDOM, while during the dry season all three constituents contributed significantly. However, the variability in Kd (PAR, 490 nm, 555 nm) was driven mainly by the variability of detrital particles and phytoplankton as opposed to CDOM. This observation explained, at least to first order, why a nutrient reduction management strategy used by the Tampa Bay Estuary Program since the 1990s led to improved water clarity in most of Tampa Bay. The findings of this study provided the optical basis to fine tune existing or develop new algorithms to estimate the various optical water quality parameters from space.

Modeles numeriques de la stimulation optique de neurones assistee par nanoparticules plasmoniques

NASA Astrophysics Data System (ADS)

Le Hir, Nicolas

La stimulation de neurones par laser emerge depuis plusieurs annees comme une alternative aux techniques plus traditionnelles de stimulation artificielle. Contrairement a celles-ci, la stimulation lumineuse ne necessite pas d'interagir directement avec le tissu organique, comme c'est le cas pour une stimulation par electrodes, et ne necessite pas de manipulation genetique comme c'est le cas pour les methodes optogenetiques. Plus recemment, la stimulation lumineuse de neurones assistee par nanoparticules a emerge comme un complement a la stimulation simplement lumineuse. L'utilisation de nanoparticules complementaires permet d'augmenter la precision spatiale du procede et de diminuer la fluence necessaire pour observer le phenomene. Ceci vient des proprietes d'interaction entre les nanoparticules et le faisceau laser, comme par exemple les proprietes d'absorption des nanoparticules. Deux phenomenes princpaux sont observes. Dans certains cas, il s'agit d'une depolarisation de la membrane, ou d'un potentiel d'action. Dans d'autres experiences, un influx de calcium vers l'interieur du neurone est detecte par une augmentation de la fluorescence d'une proteine sensible a la concentration calcique. Certaines stimulations sont globales, c'est a dire qu'une perturbation se propage a l'ensemble du neurone : c'est le cas d'un potentiel d'action. D'autres sont, au contraire, locales et ne se propagent pas a l'ensemble de la cellule. Si une stimulation lumineuse globale est rendue possible par des techniques relativement bien maitrisees a l'heure actuelle, comme l'optogenetique, une stimulation uniquement locale est plus difficile a realiser. Or, il semblerait que les methodes de stimulation lumineuse assistees par nanoparticules puissent, dans certaines conditions, offrir cette possibilite. Cela serait d'une grande aide pour conduire de nouvelles etudes sur le fonctionnement des neurones, en offrant de nouvelles possibilites experimentales en complement des possibilites actuelles. Cependant, le mecanisme physique a l'origine de la stimulation lumineuse de neurones, ainsi que celui a l'orgine de la stimulation lumineuse assistee par nanoparticules, n'est a ce jour pas totalement compris. Des hypotheses ont ete formulees concernant ce mecanisme : il pourrait etre photothermique, photomecanique, ou encore photochimique. Il se pourrait egalement que plusieurs mecanismes soient a l'oeuvre conjointement, etant donne la variete des observations. La litterature ne converge pas a ce sujet et l'existence d'un mecanisme commun aux differentes situations n'a pas ete demontree.

Micropulse laser for persistent optic disc pit maculopathy. A case report.

PubMed

Valdés-Lara, Carlos Andrés; Crim, Nicolás; García-Aguirre, Gerardo; Lule, Ismael Ávila; Morales-Cantón, Virgilio

2018-06-01

Optic disc pits (ODP) are rare and congenital anomalies of the optic disc, sometimes remaining asymptomatic. However, serous macular detachment or optic disc maculopathy is the most common complication, causing significant visual deterioration, without a current consensus about treatment. We describe a case of ODP maculopathy that was treated successfully with micropulse laser. A patient with ODP maculopathy remained with macular serous detachment after nine months of follow up after pars plana vitrectomy. Subthreshold micropulse laser was used to treat macular serous detachment, achieving a significant improvement in central macular thickness after one session. Subthreshold micropulse laser is designed to stimulate the retinal pigment epithelium without damage to the photoreceptors, resulting in absorption of subretinal and intraretinal fluid. Macular serous detachment in patients with ODP requires a prompt diagnosis and treatment to avoid damage to photoreceptors. Subthreshold micropulse laser is a potential treatment for eyes with ODP and macular serous detachment complication.

TGF-β induced PAR-1 expression promotes tumor progression and osteoclast differentiation in giant cell tumor of bone.

PubMed

Wang, Ting; Jiao, Jian; Zhang, Hao; Zhou, Wang; Li, Zhenxi; Han, Shuai; Wang, Jing; Yang, Xinghai; Huang, Quan; Wu, Zhipeng; Yan, Wangjun; Xiao, Jianru

2017-10-15

Although protease activated receptor-1 (PAR-1) has been confirmed as an oncogene in many cancers, the role of PAR-1 in giant cell tumor (GCT) of bone has been rarely reported. The mechanism of PAR-1 in tumor-induced osteoclastogenesis still remains unclear. In the present study, we detected that PAR-1 was significantly upregulated in GCT of bone compared to normal tissues, while TGF-β was also overexpressed in GCT tissues and could promote the expression of PAR-1 in a dose and time dependent manner. Using the luciferase reporter assay, we found that two downstreams of TGF-β, Smad3 and Smad4, could activate the promoter of PAR-1, which might explain the mechanism of TGF-β induced PAR-1 expression. Meanwhile, PAR-1 was also overexpressed in microvesicles from stromal cells of GCT (GCTSCs), and might be transported from GCTSCs to monocytes through microvesicles. In addition, knockout of PAR-1 by TALENs in GCTSCs inhibited tumor growth, angiogenesis and osteoclastogenesis in GCT in vitro. Using the chick CAM models, we further showed that inhibition of PAR-1 suppressed tumor growth and giant cell formation in vivo. Using microarray assay, we detected a number of genes involved in osteoclastogenesis as the possible downstreams of PAR-1, which may partly explain the mechanism of PAR-1 in GCT. In brief, for the first time, these results reveal an upstream regulatory role of TGF-β in PAR-1 expression, and PAR-1 expression promotes tumor growth, angiogenesis and osteoclast differentiation in GCT of bone. Hence, PAR-1 represents a novel potential therapeutic target for GCT of bone. © 2017 UICC.

Discovery of potent peptide-mimetic antagonists for the human thrombin receptor, protease-activated receptor-1 (PAR-1).

PubMed

Maryanoff, Bruce E; Zhang, Han-Cheng; Andrade-Gordon, Patricia; Derian, Claudia K

2003-03-01

Protease-activated receptors (PARs) represent a unique family of seven-transmembrane G-protein-coupled receptors, which are enzymatically cleaved to expose a new extracellular N-terminus that acts as a tethered activating ligand. PAR-1 is cleaved and activated by the serine protease alpha-thrombin, is expressed in various tissues (e.g. platelets and vascular cells), and is involved in cellular responses associated with hemostasis, proliferation, and tissue injury. By using a de novo design approach, we have discovered a series of potent heterocycle-based peptide-miimetic antagonists of PAR-1, exemplified by advanced leads RWJ-56110 (22) and RWJ-58259 (32). These compounds are potent, selective PAR-1 antagonists, devoid of PAR-1 agonist and thrombin inhibitory activity: they bind to PAR-1, interfere with calcium mobilization and cellular functions associated with PAR-1, and do not affect PAR-2, PAR-3, or PAR-4. RWJ-56110 was determined to be a direct inhibitor of PAR-1 activation and internalization, without affecting PAR-1 N-terminal cleavage. At high concentrations of alpha-thrombin, RWJ-56110 fully blocked activation responses in human vascular cells, but not in human platelets; whereas, at high concentrations of TRAP-6, RWJ-56110 blocked activation responses in both cell types. This result is consistent with the presence of another thrombin receptor on human platelets, namely PAR-4. RWJ-56110 and RWJ-58259 clearly interrupt the binding of a tethered ligand to its receptor. RWJ-58259 demonstrated antirestenotic activity in a rat balloon angioplasty model and antithrombotic activity in a cynomolgus monkey arterial injury model. Such PAR-1 antagonists should not only serve as useful tools to delineate the physiological and pathophysiological roles of PAR-1, but also may have therapeutic potential for treating thrombosis and restenosis in humans.

Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan.

PubMed

Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

2014-01-01

Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia.

Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan

PubMed Central

Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

2014-01-01

Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia. PMID:24455157

Using a simple apparatus to measure direct and diffuse photosynthetically active radiation at remote locations.

PubMed

Cruse, Michael J; Kucharik, Christopher J; Norman, John M

2015-01-01

Plant canopy interception of photosynthetically active radiation (PAR) drives carbon dioxide (CO2), water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM) Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal) of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the potential to support ecological research via a relatively inexpensive method to collect continuous measurements of total, direct beam and diffuse PAR in remote locations.

Using a Simple Apparatus to Measure Direct and Diffuse Photosynthetically Active Radiation at Remote Locations

PubMed Central

Cruse, Michael J.; Kucharik, Christopher J.; Norman, John M.

2015-01-01

Plant canopy interception of photosynthetically active radiation (PAR) drives carbon dioxide (CO2), water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM) Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal) of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the potential to support ecological research via a relatively inexpensive method to collect continuous measurements of total, direct beam and diffuse PAR in remote locations. PMID:25668208

Canopy reflectance, photosynthesis, and transpiration. II - The role of biophysics in the linearity of their interdependence

NASA Technical Reports Server (NTRS)

Sellers, P. J.

1987-01-01

The ability of satellite sensor systems to estimate area-averaged canopy photosynthetic and transpirative properties is evaluated. The near linear relationship between the simple ratio (SR) and normalized difference (ND) and the surface biophysical properties of canopy photosynthetically active radiation (PAR) absorption, photosynthesis, and bulk stomatal resistance is studied. The models utilized to illustrate the processes of canopy reflectance, photosynthesis, and resistance are described. The dependence of SR, the absorbed fraction of PAR, and canopy photosynthesis and resistance on total leaf area index is analyzed. It is noted that the SR and ND vegetation indices and vegetation-dependent qualities are near-linearly related due to the proportion of leaf scattering coefficient in visible and near IR wavelength regions. The data reveal that satellite sensor systems are useful for the estimation of photosynthesis and transpirative properties.

Observation de l'interaction entre atome et surface en cellule de vapeur submicrométrique

NASA Astrophysics Data System (ADS)

Dutier, G.; Saltiel, S.; Bloch, D.; Ducloy, M.; Papoyan, A.; Sarkisyan, D.

2002-06-01

Sur une cellule de vapeur d'épaisseur submicrométrique ( 300 nm), les spectres d'absorption linéaire se révèlent très peu sensibles à l'effet Doppler (les effets transitoires favorisent fortement les atomes lents), et font apparaître les effets de l'interaction van der Waals à longue portée entre atome-surface. L'étude, entreprise d'abord sur la raie de résonance D1 de Cs, est poursuivie sur une transition à deux photons vers le niveau Cs 6(D{3/2}) résonnant avec la surface de YAG de la fenêtre. Elle ouvre diverses perspectives, notamment la détection d'états liés par un puits de potentiel induit par la surface.

Matrix metalloproteases and PAR1 activation

PubMed Central

Austin, Karyn M.; Covic, Lidija

2013-01-01

Cardiovascular diseases, including atherothrombosis, are the leading cause of morbidity and mortality in the United States, Europe, and the developed world. Matrix metalloproteases (MMPs) have recently emerged as important mediators of platelet and endothelial function, and atherothrombotic disease. Protease-activated receptor-1 (PAR1) is a G protein-coupled receptor that is classically activated through cleavage of the N-terminal exodomain by the serine protease thrombin. Most recently, 2 MMPs have been discovered to have agonist activity for PAR1. Unexpectedly, MMP-1 and MMP-13 cleave the N-terminal exodomain of PAR1 at noncanonical sites, which result in distinct tethered ligands that activate G-protein signaling pathways. PAR1 exhibits metalloprotease-specific signaling patterns, known as biased agonism, that produce distinct functional outputs by the cell. Here we contrast the mechanisms of canonical (thrombin) and noncanonical (MMP) PAR1 activation, the contribution of MMP-PAR1 signaling to diseases of the vasculature, and the therapeutic potential of inhibiting MMP-PAR1 signaling with MMP inhibitors, including atherothrombotic disease, in-stent restenosis, heart failure, and sepsis. PMID:23086754

The Sound of Silence: RNAi in Poly (ADP-Ribose) Research

PubMed Central

Blenn, Christian; Wyrsch, Philippe; Althaus, Felix R.

2012-01-01

Poly(ADP-ribosyl)-ation is a nonprotein posttranslational modification of proteins and plays an integral part in cell physiology and pathology. The metabolism of poly(ADP-ribose) (PAR) is regulated by its synthesis by poly(ADP-ribose) polymerases (PARPs) and on the catabolic side by poly(ADP-ribose) glycohydrolase (PARG). PARPs convert NAD+ molecules into PAR chains that interact covalently or noncovalently with target proteins and thereby modify their structure and functions. PAR synthesis is activated when PARP1 and PARP2 bind to DNA breaks and these two enzymes account for almost all PAR formation after genotoxic stress. PARG cleaves PAR molecules into free PAR and finally ADP-ribose (ADPR) moieties, both acting as messengers in cellular stress signaling. In this review, we discuss the potential of RNAi to manipulate the levels of PARPs and PARG, and consequently those of PAR and ADPR, and compare the results with those obtained after genetic or chemical disruption. PMID:24705085

3D spongy graphene-modified screen-printed sensors for the voltammetric determination of the narcotic drug codeine.

PubMed

Mohamed, Mona A; El-Gendy, Dalia M; Ahmed, Nashaat; Banks, Craig E; Allam, Nageh K

2018-03-15

Adenine-functionalized spongy graphene (FSG) composite, fabricated via a facile and green synthetic method, has been explored as a potential electrocatalyst toward the electroanalytical sensing of codeine phosphate (COD). The synthesized composite is characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction, UV-vis absorption spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), and thermogravimetric analysis. The FSG was electrically wired via modification upon screen-printed (macro electrode) sensors, which behave as a hybrid electrode material for the sensitive and selective codeine phosphate (COD) determination in the presence of paracetamol (PAR) and caffeine (CAF). The FSG- modified sensor showed an excellent electrocatalytic response towards the sensing of COD with a wide linear response range of 2.0 × 10 -8 -2.0 × 10 -4 M and a detection limit (LOD) of 5.8 × 10 -9 M, indicating its potential for the sensing of COD in clinical samples and pharmaceutical formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-Temperature Atomic Layer Deposition of CuSbS2 for Thin-Film Photovoltaics.

PubMed

Riha, Shannon C; Koegel, Alexandra A; Emery, Jonathan D; Pellin, Michael J; Martinson, Alex B F

2017-02-08

Copper antimony sulfide (CuSbS 2 ) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (∼1.5 eV), large absorption coefficient (>10 4 cm -1 ), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbS 2 thin films via atomic layer deposition has been developed. After a short (15 min) postprocess anneal at 225 °C, the ALD-grown CuSbS 2 films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >10 4 cm -1 , as well as a hole concentration of 10 15 cm -3 . Finally, the ALD-grown CuSbS 2 films were paired with ALD-grown TiO 2 to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbS 2 PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbS 2 /CdS heterojunction PV devices. While far from optimized, this work demonstrates the potential for ALD-grown CuSbS 2 thin films in environmentally benign photovoltaics.

Proteolytic Activation of the Protease-activated Receptor (PAR)-2 by the Glycosylphosphatidylinositol-anchored Serine Protease Testisin*

PubMed Central

Driesbaugh, Kathryn H.; Buzza, Marguerite S.; Martin, Erik W.; Conway, Gregory D.; Kao, Joseph P. Y.; Antalis, Toni M.

2015-01-01

Protease-activated receptors (PARs) are a family of seven-transmembrane, G-protein-coupled receptors that are activated by multiple serine proteases through specific N-terminal proteolytic cleavage and the unmasking of a tethered ligand. The majority of PAR-activating proteases described to date are soluble proteases that are active during injury, coagulation, and inflammation. Less investigation, however, has focused on the potential for membrane-anchored serine proteases to regulate PAR activation. Testisin is a unique trypsin-like serine protease that is tethered to the extracellular membrane of cells through a glycophosphatidylinositol (GPI) anchor. Here, we show that the N-terminal domain of PAR-2 is a substrate for testisin and that proteolytic cleavage of PAR-2 by recombinant testisin activates downstream signaling pathways, including intracellular Ca2+ mobilization and ERK1/2 phosphorylation. When testisin and PAR-2 are co-expressed in HeLa cells, GPI-anchored testisin specifically releases the PAR-2 tethered ligand. Conversely, knockdown of endogenous testisin in NCI/ADR-Res ovarian tumor cells reduces PAR-2 N-terminal proteolytic cleavage. The cleavage of PAR-2 by testisin induces activation of the intracellular serum-response element and NFκB signaling pathways and the induction of IL-8 and IL-6 cytokine gene expression. Furthermore, the activation of PAR-2 by testisin results in the loss and internalization of PAR-2 from the cell surface. This study reveals a new biological substrate for testisin and is the first demonstration of the activation of a PAR by a serine protease GPI-linked to the cell surface. PMID:25519908

Role of Minerogenic Particles in Light Scattering in Lakes and a River in Central New York

DTIC Science & Technology

2007-09-10

calibration protocol. Corrections for differences in the ten samples for both elemental and morphometric pure-water absorption and attenuation due to tem...PA’>, (6) Morphometric characterization of particles by SAX is based on a "rotating chord" algorithm, which pro- where N,,, is the number of...to characterize individual minerogenic par- nous versus autochthonous) is essential information ticles both compositionally and morphometrically for

Absorbed photosynthetically active radiation of steppe vegetation and sun-view geometry effects on APAR estimates

NASA Technical Reports Server (NTRS)

Walter-Shea, E. A.; Blad, B. L.; Mesarch, M. A.; Hays, C. J.; Deering, D. W.; Eck, T. F.

1992-01-01

Instantaneous fractions of absorbed photosynthetically active radiation (APAR) were measured at the Streletskaya Steppe Reserve in conjunction with canopy bidirectional-reflected radiation measured at solar zenith angles ranging between 37 and 74 deg during the Kursk experiment (KUREX-91). APAR values were higher for KUREX-91 than those for the first ISLSCP field experiment (FIFE-89) and the amount of APAR of a canopy was a function of solar zenith angle, decreasing as solar zenith angle increased at the resrve. Differences in absorption are attributed to leaf area index (LAI) and leaf angle distribution and subsequently transmitted radiation interactions. LAIs were considerably higher at the reserve than those at the FIFE site. Leaf angle distributions of the reserve approach a uniform distribution while distributions at the FIFE site more closely approximate erectophile distributions. Reflected photosynthetically active radiation (PAR) components at KUREX-91 and FIFE-89 were similar in magnitude and in their response to solar zenith angle. Transmitted PAR increased with increasing solar zenith angle at KUREX-91 and decreased with increasing solar zenith angle at FIFE-89. Transmitted PAR at FIFE-89 was considerably larger than those at KUREX-91.

Neuronal inhibition and synaptic plasticity of basal ganglia neurons in Parkinson's disease

PubMed Central

Milosevic, Luka; Kalia, Suneil K; Hodaie, Mojgan; Lozano, Andres M; Fasano, Alfonso; Popovic, Milos R; Hutchison, William D

2018-01-01

Abstract Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson’s disease symptoms. The therapeutic benefits of deep brain stimulation are frequency-dependent, but the underlying physiological mechanisms remain unclear. To advance deep brain stimulation therapy an understanding of fundamental mechanisms is critical. The objectives of this study were to (i) compare the frequency-dependent effects on cell firing in subthalamic nucleus and substantia nigra pars reticulata; (ii) quantify frequency-dependent effects on short-term plasticity in substantia nigra pars reticulata; and (iii) investigate effects of continuous long-train high frequency stimulation (comparable to conventional deep brain stimulation) on synaptic plasticity. Two closely spaced (600 µm) microelectrodes were advanced into the subthalamic nucleus (n = 27) and substantia nigra pars reticulata (n = 14) of 22 patients undergoing deep brain stimulation surgery for Parkinson’s disease. Cell firing and evoked field potentials were recorded with one microelectrode during stimulation trains from the adjacent microelectrode across a range of frequencies (1–100 Hz, 100 µA, 0.3 ms, 50–60 pulses). Subthalamic firing attenuated with ≥20 Hz (P < 0.01) stimulation (silenced at 100 Hz), while substantia nigra pars reticulata decreased with ≥3 Hz (P < 0.05) (silenced at 50 Hz). Substantia nigra pars reticulata also exhibited a more prominent increase in transient silent period following stimulation. Patients with longer silent periods after 100 Hz stimulation in the subthalamic nucleus tended to have better clinical outcome after deep brain stimulation. At ≥30 Hz the first evoked field potential of the stimulation train in substantia nigra pars reticulata was potentiated (P < 0.05); however, the average amplitude of the subsequent potentials was rapidly attenuated (P < 0.01). This is suggestive of synaptic facilitation followed by rapid depression. Paired pulse ratios calculated at the beginning of the train revealed that 20 Hz (P < 0.05) was the minimum frequency required to induce synaptic depression. Lastly, the average amplitude of evoked field potentials during 1 Hz pulses showed significant inhibitory synaptic potentiation after long-train high frequency stimulation (P < 0.001) and these increases were coupled with increased durations of neuronal inhibition (P < 0.01). The subthalamic nucleus exhibited a higher frequency threshold for stimulation-induced inhibition than the substantia nigra pars reticulata likely due to differing ratios of GABA:glutamate terminals on the soma and/or the nature of their GABAergic inputs (pallidal versus striatal). We suggest that enhancement of inhibitory synaptic plasticity, and frequency-dependent potentiation and depression are putative mechanisms of deep brain stimulation. Furthermore, we foresee that future closed-loop deep brain stimulation systems (with more frequent off stimulation periods) may benefit from inhibitory synaptic potentiation that occurs after high frequency stimulation. PMID:29236966

PAR-1 and thrombin: the ties that bind the microenvironment to melanoma metastasis.

PubMed

Zigler, Maya; Kamiya, Takafumi; Brantley, Emily C; Villares, Gabriel J; Bar-Eli, Menashe

2011-11-01

Progression of melanoma is dependent on cross-talk between tumor cells and the adjacent microenvironment. The thrombin receptor, protease-activated receptor-1 (PAR-1), plays a key role in exerting this function during melanoma progression. PAR-1 and its activating factors, which are expressed on tumor cells and the surrounding stroma, induce not only coagulation but also cell signaling, which promotes the metastatic phenotype. Several adhesion molecules, cytokines, growth factors, and proteases have recently been identified as downstream targets of PAR-1 and have been shown to modulate interactions between tumor cells and the microenvironment in the process of melanoma growth and metastasis. Inhibiting such interactions by targeting PAR-1 could potentially be a useful therapeutic modality for melanoma patients. ©2011 AACR.

Shining Light on Benthic Macroalgae: Mechanisms of Complementarity in Layered Macroalgal Assemblages

PubMed Central

Tait, Leigh W.; Hawes, Ian; Schiel, David R.

2014-01-01

Phototrophs underpin most ecosystem processes, but to do this they need sufficient light. This critical resource, however, is compromised along many marine shores by increased loads of sediments and nutrients from degraded inland habitats. Increased attenuation of total irradiance within coastal water columns due to turbidity is known to reduce species' depth limits and affect the taxonomic structure and architecture of algal-dominated assemblages, but virtually no attention has been paid to the potential for changes in spectral quality of light energy to impact production dynamics. Pioneering studies over 70 years ago showed how different pigmentation of red, green and brown algae affected absorption spectra, action spectra, and photosynthetic efficiency across the PAR (photosynthetically active radiation) spectrum. Little of this, however, has found its way into ecological syntheses of the impacts of optically active contaminants on coastal macroalgal communities. Here we test the ability of macroalgal assemblages composed of multiple functional groups (including representatives from the chlorophyta, rhodophyta and phaeophyta) to use the total light resource, including different light wavelengths and examine the effects of suspended sediments on the penetration and spectral quality of light in coastal waters. We show that assemblages composed of multiple functional groups are better able to use light throughout the PAR spectrum. Macroalgal assemblages with four sub-canopy species were between 50–75% more productive than assemblages with only one or two sub-canopy species. Furthermore, attenuation of the PAR spectrum showed both a loss of quanta and a shift in spectral distribution with depth across coastal waters of different clarity, with consequences to productivity dynamics of diverse layered assemblages. The processes of light complementarity may help provide a mechanistic understanding of how altered turbidity affects macroalgal assemblages in coastal waters, which are increasingly threatened by diminishing light quantity and altered spectral distributions through sedimentation and eutrophication. PMID:25438045

Novel approach for computing photosynthetically active radiation for productivity modeling using remotely sensed images in the Great Plains, United States

USGS Publications Warehouse

Singh, Ramesh K.; Liu, Shu-Guang; Tieszen, Larry L.; Suyker, Andrew E.; Verma, Shashi B.

2012-01-01

Gross primary production (GPP) is a key indicator of ecosystem performance, and helps in many decision-making processes related to environment. We used the Eddy covariancelight use efficiency (EC-LUE) model for estimating GPP in the Great Plains, United States in order to evaluate the performance of this model. We developed a novel algorithm for computing the photosynthetically active radiation (PAR) based on net radiation. A strong correlation (R2=0.94,N=24) was found between daily PAR and Landsat-based mid-day instantaneous net radiation. Though the Moderate Resolution Spectroradiometer (MODIS) based instantaneous net radiation was in better agreement (R2=0.98,N=24) with the daily measured PAR, there was no statistical significant difference between Landsat based PAR and MODIS based PAR. The EC-LUE model validation also confirms the need to consider biological attributes (C3 versus C4 plants) for potential light use efficiency. A universal potential light use efficiency is unable to capture the spatial variation of GPP. It is necessary to use C3 versus C4 based land use/land cover map for using EC-LUE model for estimating spatiotemporal distribution of GPP.

PAR-2-mediated control of barrier function and motility differs between early and late phases of postinfectious gut dysfunction in the rat.

PubMed

Fernández-Blanco, Joan Antoni; Fernández-Blanco, Juan A; Hollenberg, Morley D; Martínez, Vicente; Vergara, Patri

2013-02-15

Proteinase-activated receptor-2 (PAR-2) and mast cell (MC) mediators contribute to inflammatory and functional gastrointestinal disorders. We aimed to characterize jejunal PAR-2-mediated responses and the potential MC involvement in the early and late phases of a rat model of postinfectious gut dysfunction. Jejunal tissues of control and Trichinella spiralis-infected (14 and 30 days postinfection) rats, treated or not with the MC stabilizer, ketotifen, were used. Histopathology and immunostaining were used to characterize inflammation, PAR-2 expression, and mucosal and connective tissue MCs. Epithelial barrier function (hydroelectrolytic transport and permeability) and motility were assessed in vitro in basal conditions and after PAR-2 activation. Intestinal inflammation on day 14 postinfection (early phase) was significantly resolved by day 30 (late phase) although MC counts and epithelial permeability remained increased. PAR-2-mediated ion transport (Ussing chambers, in vitro) and epithelial surface PAR-2 expression were reduced in the early phase, with a trend toward normalization during the late phase. In control conditions, PAR-2 activation (organ bath) induced biphasic motor responses (relaxation followed by excitation). At 14 days postinfection, spontaneous contractility and PAR-2-mediated relaxations were enhanced; motor responses were normalized on day 30. Postinfectious changes in PAR-2 functions were not affected by ketotifen treatment. We concluded that, in the rat model of Trichinella spiralis infection, alterations of intestinal PAR-2 function and expression depend on the inflammatory phase considered. A lack of a ketotifen effect suggests no interplay between MCs and PAR-2-mediated motility and ion transport alterations. These observations question the role of MC mediators in PAR-2-modulating postinfectious gut dysfunction.

Proteolytic activation of the protease-activated receptor (PAR)-2 by the glycosylphosphatidylinositol-anchored serine protease testisin.

PubMed

Driesbaugh, Kathryn H; Buzza, Marguerite S; Martin, Erik W; Conway, Gregory D; Kao, Joseph P Y; Antalis, Toni M

2015-02-06

Protease-activated receptors (PARs) are a family of seven-transmembrane, G-protein-coupled receptors that are activated by multiple serine proteases through specific N-terminal proteolytic cleavage and the unmasking of a tethered ligand. The majority of PAR-activating proteases described to date are soluble proteases that are active during injury, coagulation, and inflammation. Less investigation, however, has focused on the potential for membrane-anchored serine proteases to regulate PAR activation. Testisin is a unique trypsin-like serine protease that is tethered to the extracellular membrane of cells through a glycophosphatidylinositol (GPI) anchor. Here, we show that the N-terminal domain of PAR-2 is a substrate for testisin and that proteolytic cleavage of PAR-2 by recombinant testisin activates downstream signaling pathways, including intracellular Ca(2+) mobilization and ERK1/2 phosphorylation. When testisin and PAR-2 are co-expressed in HeLa cells, GPI-anchored testisin specifically releases the PAR-2 tethered ligand. Conversely, knockdown of endogenous testisin in NCI/ADR-Res ovarian tumor cells reduces PAR-2 N-terminal proteolytic cleavage. The cleavage of PAR-2 by testisin induces activation of the intracellular serum-response element and NFκB signaling pathways and the induction of IL-8 and IL-6 cytokine gene expression. Furthermore, the activation of PAR-2 by testisin results in the loss and internalization of PAR-2 from the cell surface. This study reveals a new biological substrate for testisin and is the first demonstration of the activation of a PAR by a serine protease GPI-linked to the cell surface. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures

NASA Astrophysics Data System (ADS)

Hegazy, Maha A.; Lotfy, Hayam M.; Mowaka, Shereen; Mohamed, Ekram Hany

2016-07-01

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations.

Spectroscopie résolue en temps par continuum femtoseconde Applications en neurobiologie

NASA Astrophysics Data System (ADS)

Ramstein, S.; Mottin, S.

2003-06-01

La spectroscopie résolue en temps utilisant un laser blanc femtoseconde est appliquée à la mesure in vivo des principaux absorbeurs du cerveau. Après génération adéquate du continuum de lumière blanche femtoseconde (50mW/[580-756nm] à 1Hz), cette source se propage dans la calvaria, les méninges et le cortex chez le rat anesthésié. La transmission est étudiée sur 7mm de distance entre l'impact laser et la fibre optique de collection. Le signal transmis est analysé dans la fenêtre 580-760nm, par un spectromètre couplé à une caméra à balayage de fente permettant la décorrélation de l'absorption et de la diffusion.

Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells

NASA Astrophysics Data System (ADS)

Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm; Iversen, Frank; Liu, Zhuo; Thomsen, Karen; Pedersen, Michael; Skrydstrup, Troels; Nielsen, Niels Chr.; Ploug, Michael; Kjems, Jørgen

2013-08-01

Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr32922d

Protease-Activated Receptor 2 Activation Inhibits N-Type Ca2+ Currents in Rat Peripheral Sympathetic Neurons

PubMed Central

Kim, Young-Hwan; Ahn, Duck-Sun; Kim, Myeong Ok; Joeng, Ji-Hyun; Chung, Seungsoo

2014-01-01

The protease-activated receptor (PAR)-2 is highly expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although several mechanisms have been suggested to explain PAR-2-induced hypotension, the precise mechanism remains to be elucidated. To investigate this possibility, we investigated the effects of PAR-2 activation on N-type Ca2+ currents (ICa-N) in isolated neurons of the celiac ganglion (CG), which is involved in the sympathetic regulation of mesenteric artery vascular tone. PAR-2 agonists irreversibly diminished voltage-gated Ca2+ currents (ICa), measured using the patch-clamp method, in rat CG neurons, whereas thrombin had little effect on ICa. This PAR-2-induced inhibition was almost completely prevented by ω-CgTx, a potent N-type Ca2+ channel blocker, suggesting the involvement of N-type Ca2+ channels in PAR-2-induced inhibition. In addition, PAR-2 agonists inhibited ICa–N in a voltage-independent manner in rat CG neurons. Moreover, PAR-2 agonists reduced action potential (AP) firing frequency as measured using the current-clamp method in rat CG neurons. This inhibition of AP firing induced by PAR-2 agonists was almost completely prevented by ω-CgTx, indicating that PAR-2 activation may regulate the membrane excitability of peripheral sympathetic neurons through modulation of N-type Ca2+ channels. In conclusion, the present findings demonstrate that the activation of PAR-2 suppresses peripheral sympathetic outflow by modulating N-type Ca2+ channel activity, which appears to be involved in PAR-2-induced hypotension, in peripheral sympathetic nerve terminals. PMID:25410909

PAR1 activation affects the neurotrophic properties of Schwann cells.

PubMed

Pompili, Elena; Fabrizi, Cinzia; Somma, Francesca; Correani, Virginia; Maras, Bruno; Schininà, Maria Eugenia; Ciraci, Viviana; Artico, Marco; Fornai, Francesco; Fumagalli, Lorenzo

2017-03-01

Protease-activated receptor-1 (PAR1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR1 mRNA increased in response to sciatic nerve transection. In the sciatic nerve, functional PAR1 receptor was reported at the level of non-compacted Schwann cell myelin microvilli of the nodes of Ranvier. Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination. The present study was undertaken in order to determine if the activation of PAR1 affects the neurotrophic properties of Schwann cells. Our results suggest that the stimulation of PAR1 could potentiate the Schwann cell ability to favour nerve regeneration. In fact, the conditioned medium obtained from Schwann cell cultures challenged with a specific PAR1 activating peptide (PAR1 AP) displays increased neuroprotective and neurotrophic properties with respect to the culture medium from untreated Schwann cells. The proteomic analysis of secreted proteins in untreated and PAR1 AP-treated Schwann cells allowed the identification of factors differentially expressed in the two samples. Some of them (such as macrophage migration inhibitory factor, matrix metalloproteinase-2, decorin, syndecan 4, complement C1r subcomponent, angiogenic factor with G patch and FHA domains 1) appear to be transcriptionally regulated after PAR1 AP treatment as shown by RT-PCR. Copyright © 2017 Elsevier Inc. All rights reserved.

Pharmacophore-based virtual screening, biological evaluation and binding mode analysis of a novel protease-activated receptor 2 antagonist

NASA Astrophysics Data System (ADS)

Cho, Nam-Chul; Seo, Seoung-Hwan; Kim, Dohee; Shin, Ji-Sun; Ju, Jeongmin; Seong, Jihye; Seo, Seon Hee; Lee, Iiyoun; Lee, Kyung-Tae; Kim, Yun Kyung; No, Kyoung Tai; Pae, Ae Nim

2016-08-01

Protease-activated receptor 2 (PAR2) is a G protein-coupled receptor, mediating inflammation and pain signaling in neurons, thus it is considered to be a potential therapeutic target for inflammatory diseases. In this study, we performed a ligand-based virtual screening of 1.6 million compounds by employing a common-feature pharmacophore model and two-dimensional similarity search to identify a new PAR2 antagonist. The common-feature pharmacophore model was established based on the biological screening results of our in-house library. The initial virtual screening yielded a total number of 47 hits, and additional biological activity tests including PAR2 antagonism and anti-inflammatory effects resulted in a promising candidate, compound 43, which demonstrated an IC50 value of 8.22 µM against PAR2. In next step, a PAR2 homology model was constructed using the crystal structure of the PAR1 as a template to explore the binding mode of the identified ligands. A molecular docking method was optimized by comparing the binding modes of a known PAR2 agonist GB110 and antagonist GB83, and applied to predict the binding mode of our hit compound 43. In-depth docking analyses revealed that the hydrophobic interaction with Phe2435.39 is crucial for PAR2 ligands to exert antagonistic activity. MD simulation results supported the predicted docking poses that PAR2 antagonist blocked a conformational rearrangement of Na+ allosteric site in contrast to PAR2 agonist that showed Na+ relocation upon GPCR activation. In conclusion, we identified new a PAR2 antagonist together with its binding mode, which provides useful insights for the design and development of PAR2 ligands.

Monoradiculopathy and secondary segmental instability caused by postoperative pars interarticularis fracture: a case report.

PubMed

Kaner, Tuncay; Tutkan, Ibrahim

2009-04-01

Instability can develop after lumbar spinal surgery. What is also known as secondary segmental instability is one of the important causes of failed back syndrome. In this paper, we described a 45-year-old female patient who was diagnosed with secondary segmental instability caused by left L3 pars interarticularis fracture after a high lumbar disc surgery and was subsequently treated with re-operation. We evaluated the clinical course, diagnosis, and treatment methods for secondary segmental instability caused by postoperative pars interarticularis fracture. Furthermore, we emphasized the importance of preserving the pars interarticularis during upper lumbar disc surgeries in order to avoid a potential stress fracture.

Effects of silenced PAR-2 on cell proliferation, invasion and metastasis of esophageal cancer.

PubMed

Chen, Jinmei; Xie, Liqun; Zheng, Yanmin; Liu, Caihong

2017-10-01

The present study aimed to investigate the effect of protease-activated receptor 2 (PAR-2) on cell proliferation, invasion and metastasis in the esophageal EC109 cell line. Two short hairpin RNA (shRNA) expression plasmids were constructed based on the PAR-2 mRNA sequence in humans, and they were transfected into the EC109 esophageal cancer cell line, and the stable interference cell line (shRNA-PAR-2 EC109) was obtained by puromycin selection. Following transfection of PAR-2 shRNA-1, PAR-2 expression was significantly downregulated in mRNA level and protein level in EC109 cells (P<0.05). The proliferation of EC109 cells transfected with PAR-2 shRNA was significantly lower than the negative control group (P<0.05). At 24, 48 and 72 h, the ratio of proliferation inhibition was 15.92, 24.89 and 32.28%, respectively. Compared with the control group, S-phase arrest was observed in cells transfected with shRNA-PAR-2. The ratio of cells in the S phase was 32.79±4.06, 26.54±1.37 and 33.45±2.46% at 24, 48 and 72 h, respectively. For invasion, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.05). For metastasis assay, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.01). In the present study, the PAR-2 shRNA plasmid was constructed successfully, which can significantly downregulate PAR-2 expression in EC109 cells. Subsequent to silencing of PAR-2, the proliferation of EC109 cells was inhibited and the capabilities of invasion and migration were reduced. It is indicated that PAR-2 may be a potential target in esophageal cancer.

Effects of silenced PAR-2 on cell proliferation, invasion and metastasis of esophageal cancer

PubMed Central

Chen, Jinmei; Xie, Liqun; Zheng, Yanmin; Liu, Caihong

2017-01-01

The present study aimed to investigate the effect of protease-activated receptor 2 (PAR-2) on cell proliferation, invasion and metastasis in the esophageal EC109 cell line. Two short hairpin RNA (shRNA) expression plasmids were constructed based on the PAR-2 mRNA sequence in humans, and they were transfected into the EC109 esophageal cancer cell line, and the stable interference cell line (shRNA-PAR-2 EC109) was obtained by puromycin selection. Following transfection of PAR-2 shRNA-1, PAR-2 expression was significantly downregulated in mRNA level and protein level in EC109 cells (P<0.05). The proliferation of EC109 cells transfected with PAR-2 shRNA was significantly lower than the negative control group (P<0.05). At 24, 48 and 72 h, the ratio of proliferation inhibition was 15.92, 24.89 and 32.28%, respectively. Compared with the control group, S-phase arrest was observed in cells transfected with shRNA-PAR-2. The ratio of cells in the S phase was 32.79±4.06, 26.54±1.37 and 33.45±2.46% at 24, 48 and 72 h, respectively. For invasion, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.05). For metastasis assay, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.01). In the present study, the PAR-2 shRNA plasmid was constructed successfully, which can significantly downregulate PAR-2 expression in EC109 cells. Subsequent to silencing of PAR-2, the proliferation of EC109 cells was inhibited and the capabilities of invasion and migration were reduced. It is indicated that PAR-2 may be a potential target in esophageal cancer. PMID:28943918

The Role of PAR2 in TGF-β1-Induced ERK Activation and Cell Motility

PubMed Central

Ungefroren, Hendrik; Witte, David; Fiedler, Christian; Gädeken, Thomas; Kaufmann, Roland; Lehnert, Hendrik

2017-01-01

Background: Recently, the expression of proteinase-activated receptor 2 (PAR2) has been shown to be essential for activin receptor-like kinase 5 (ALK5)/SMAD-mediated signaling and cell migration by transforming growth factor (TGF)-β1. However, it is not known whether activation of non-SMAD TGF-β signaling (e.g., RAS–RAF–MEK–extracellular signal-regulated kinase (ERK) signaling) is required for cell migration and whether it is also dependent on PAR2. Methods: RNA interference was used to deplete cells of PAR2, followed by xCELLigence technology to measure cell migration, phospho-immunoblotting to assess ERK1/2 activation, and co-immunoprecipitation to detect a PAR2–ALK5 physical interaction. Results: Inhibition of ERK signaling with the MEK inhibitor U0126 blunted the ability of TGF-β1 to induce migration in pancreatic cancer Panc1 cells. ERK activation in response to PAR2 agonistic peptide (PAR2–AP) was strong and rapid, while it was moderate and delayed in response to TGF-β1. Basal and TGF-β1-dependent ERK, but not SMAD activation, was blocked by U0126 in Panc1 and other cell types indicating that ERK activation is downstream or independent of SMAD signaling. Moreover, cellular depletion of PAR2 in HaCaT cells strongly inhibited TGF-β1-induced ERK activation, while the biased PAR2 agonist GB88 at 10 and 100 µM potentiated TGF-β1-dependent ERK activation and cell migration. Finally, we provide evidence for a physical interaction between PAR2 and ALK5. Our data show that both PAR2–AP- and TGF-β1-induced cell migration depend on ERK activation, that PAR2 expression is crucial for TGF-β1-induced ERK activation, and that the functional cooperation of PAR2 and TGF-β1 involves a physical interaction between PAR2 and ALK5. PMID:29261154

Regulation of long-term repopulating hematopoietic stem cells by EPCR/PAR1 signaling

PubMed Central

Gur-Cohen, Shiri; Kollet, Orit; Graf, Claudine; Esmon, Charles T.; Ruf, Wolfram; Lapidot, Tsvee

2016-01-01

The common developmental origin of endothelial and hematopoietic cells is manifested by coexpression of several cell surface receptors. Adult murine bone marrow (BM) long-term repopulating hematopoietic stem cells (LT-HSCs), endowed with the highest repopulation and self-renewal potential, express endothelial protein C receptor (EPCR), which is used as a marker to isolate them. EPCR/PAR1 signaling in endothelial cells has anticoagulant and anti-inflammatory roles, while thrombin/PAR1 signaling induces coagulation and inflammation. Recent studies define two new PAR1-mediated signaling cascades that regulate EPCR+ LT-HSC BM retention and egress. EPCR/PAR1 signaling facilitates LT-HSC BM repopulation, retention, survival, and chemotherapy resistance by restricting nitric oxide (NO) production, maintaining NOlow LT-HSC BM retention with increased VLA4 expression, affinity, and adhesion. Conversely, acute stress and clinical mobilization upregulate thrombin generation and activate different PAR1 signaling which overcomes BM EPCR+ LT-HSC retention, inducing their recruitment to the bloodstream. Thrombin/PAR1 signaling induces NO generation, TACE-mediated EPCR shedding, and upregulation of CXCR4 and PAR1, leading to CXCL12-mediated stem and progenitor cell mobilization. This review discusses new roles for factors traditionally viewed as coagulation related, which independently act in the BM to regulate PAR1 signaling in bone- and blood-forming progenitor cells, navigating their fate by controlling NO production. PMID:26928241

Absorption of Some Mineral Salts by Root System of Different Woody Species and Accumulation over a Whole Vegetative Cycle; ABSORPTION DE QUELQUES SELS PAR L'APPAREIL RADICULAIRE DE DIFFERENTES ESPECES LIGNEUSES ET ACCUMULATION AU COURS D'UN CYCLE VEGETATIF COMPLET

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

Gagnaire, J.

1963-01-01

The concentration power of plant tissues and the translocation speed of mineral salts vary considerably with the absorbed salt, the botanical species, the considered tissue, and the part of the vegetative cycle. In Grenoble, with Picea excelsa, the true dormance is short and is accompanied by a pre-dormance period and a post dormance period. In the vegetative period, Picea excelsa leaves concentrate less mineral salt than Acer campestris leaves (coefficient 2 for Ca--3 for phosphates) and Populus nigra leaves (coefficient 3 for Ca, coefficient 5 for phosphates). Results of tracer studies are tabulated. (C.H.)

Shear stress reduces protease activated receptor-1 expression in human endothelial cells

NASA Technical Reports Server (NTRS)

Nguyen, K. T.; Eskin, S. G.; Patterson, C.; Runge, M. S.; McIntire, L. V.

2001-01-01

Shear stress has been shown to regulate several genes involved in the thrombotic and proliferative functions of endothelial cells. Thrombin receptor (protease-activated receptor-1: PAR-1) increases at sites of vascular injury, which suggests an important role for PAR-1 in vascular diseases. However, the effect of shear stress on PAR-1 expression has not been previously studied. This work investigates effects of shear stress on PAR-1 gene expression in both human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (HMECs). Cells were exposed to different shear stresses using a parallel plate flow system. Northern blot and flow cytometry analysis showed that shear stress down-regulated PAR-1 messenger RNA (mRNA) and protein levels in both HUVECs and HMECs but with different thresholds. Furthermore, shear-reduced PAR-1 mRNA was due to a decrease of transcription rate, not increased mRNA degradation. Postshear stress release of endothelin-1 in response to thrombin was reduced in HUVECs and HMECs. Moreover, inhibitors of potential signaling pathways applied during shear stress indicated mediation of the shear-decreased PAR-1 expression by protein kinases. In conclusion, shear stress exposure reduces PAR-1 gene expression in HMECs and HUVECs through a mechanism dependent in part on protein kinases, leading to altered endothelial cell functional responses to thrombin.

Influence of Genetic Ancestry on INDEL Markers of NFKβ1, CASP8, PAR1, IL4 and CYP19A1 Genes in Leprosy Patients.

PubMed

Pinto, Pablo; Salgado, Claudio; Santos, Ney Pereira Carneiro; Santos, Sidney; Ribeiro-dos-Santos, Ândrea

2015-01-01

Leprosy is an insidious infectious disease caused by the obligate intracellular bacteria Mycobacterium leprae, and host genetic factors can modulate the immune response and generate distinct categories of leprosy susceptibility that are also influenced by genetic ancestry. We investigated the possible effects of CYP19A1 [rs11575899], NFKβ1 [rs28362491], IL1α [rs3783553], CASP8 [rs3834129], UGT1A1 [rs8175347], PAR1 [rs11267092], CYP2E1 [INDEL 96pb] and IL4 [rs79071878] genes in a group of 141 leprosy patients and 180 healthy individuals. The INDELs were typed by PCR Multiplex in ABI PRISM 3130 and analyzed with GeneMapper ID v3.2. The NFKβ1, CASP8, PAR1 and IL4 INDELs were associated with leprosy susceptibility, while NFKβ1, CASP8, PAR1 and CYP19A1 were associated with the MB (Multibacilary) clinical form of leprosy. NFKβ1 [rs28362491], CASP8 [rs3834129], PAR1 [rs11267092] and IL4 [rs79071878] genes are potential markers for susceptibility to leprosy development, while the INDELs in NFKβ1, CASP8, PAR1 and CYP19A1 (rs11575899) are potential markers for the severe clinical form MB. Moreover, all of these markers are influenced by genetic ancestry, and European contribution increases the risk to leprosy development, in other hand an increase in African contribution generates protection against leprosy.

Field estimates of body drag coefficient on the basis of dives in passerine birds.

PubMed

Hedenström, A; Liechti, F

2001-03-01

During forward flight, a bird's body generates drag that tends to decelerate its speed. By flapping its wings, or by converting potential energy into work if gliding, the bird produces both lift and thrust to balance the pull of gravity and drag. In flight mechanics, a dimensionless number, the body drag coefficient (C(D,par)), describes the magnitude of the drag caused by the body. The drag coefficient depends on the shape (or streamlining), the surface texture of the body and the Reynolds number. It is an important variable when using flight mechanical models to estimate the potential migratory flight range and characteristic flight speeds of birds. Previous wind tunnel measurements on dead, frozen bird bodies indicated that C(D,par) is 0.4 for small birds, while large birds should have lower values of approximately 0.2. More recent studies of a few birds flying in a wind tunnel suggested that previous values probably overestimated C(D,par). We measured maximum dive speeds of passerine birds during the spring migration across the western Mediterranean. When the birds reach their top speed, the pull of gravity should balance the drag of the body (and wings), giving us an opportunity to estimate C(D,par). Our results indicate that C(D,par) decreases with increasing Reynolds number within the range 0.17-0.77, with a mean C(D,par) of 0.37 for small passerines. A somewhat lower mean value could not be excluded because diving birds may control their speed below the theoretical maximum. Our measurements therefore support the notion that 0.4 (the 'old' default value) is a realistic value of C(D,par) for small passerines.

u-PAR expression in cancer associated fibroblast: new acquisitions in multiple myeloma progression.

PubMed

Ciavarella, S; Laurenzana, A; De Summa, S; Pilato, B; Chillà, A; Lacalamita, R; Minoia, C; Margheri, F; Iacobazzi, A; Rana, A; Merchionne, F; Fibbi, G; Del Rosso, M; Guarini, A; Tommasi, S; Serratì, S

2017-03-24

Multiple Myeloma (MM) is a B-cell malignancy in which clonal plasma cells progressively expand within the bone marrow (BM) as effect of complex interactions with extracellular matrix and a number of microenvironmental cells. Among these, cancer-associated fibroblasts (CAF) mediate crucial reciprocal signals with MM cells and are associated to aggressive disease and poor prognosis. A large body of evidence emphasizes the role of the urokinase plasminogen activator (u-PA) and its receptor u-PAR in potentiating the invasion capacity of tumor plasma cells, but little is known about their role in the biology of MM CAF. In this study, we investigated the u-PA/u-PAR axis in MM-associated fibroblasts and explore additional mechanisms of tumor/stroma interplay in MM progression. CAF were purified from total BM stromal fraction of 64 patients including monoclonal gammopathy of undetermined significance, asymptomatic and symptomatic MM, as well as MM in post-treatment remission. Flow cytometry, Real Time PCR and immunofluorescence were performed to investigate the u-PA/u-PAR system in relation to the level of activation of CAF at different stages of the disease. Moreover, proliferation and invasion assays coupled with silencing experiments were used to prove, at functional level, the function of u-PAR in CAF. We found higher activation level, along with increased expression of pro-invasive molecules, including u-PA, u-PAR and metalloproteinases, in CAF from patients with symptomatic MM compared to the others stages of the disease. Consistently, CAF from active MM as well as U266 cell line under the influence of medium conditioned by active MM CAF, display higher proliferative rate and invasion potential, which were significantly restrained by u-PAR gene expression inhibition. Our data suggest that the stimulation of u-PA/u-PAR system contributes to the activated phenotype and function of CAF during MM progression, providing a biological rationale for future targeted therapies against MM.

Proteinase-Activated Receptor-2 Sensitivity of Amplified TRPA1 Activity in Skeletal Muscle Afferent Nerves and Exercise Pressor Reflex in Rats with Femoral Artery Occlusion

PubMed Central

Xing, Jihong; Li, Jianhua

2017-01-01

Background/Aims Limb ischemia occurs in peripheral artery disease (PAD). Sympathetic nerve activity (SNA) that regulates blood flow directed to the ischemic limb is exaggerated during exercise in this disease, and transient receptor potential channel A1 (TRPA1) in thin-fiber muscle afferents contributes to the amplified sympathetic response. The purpose of the present study was to determine the role of proteinase-activated receptor-2 (PAR2) in regulating abnormal TRPA1 function and the TRPA1-mediated sympathetic component of the exercise pressor reflex. Methods A rat model of femoral artery ligation was employed to study PAD. Dorsal root ganglion (DRG) tissues were obtained to examine the protein levels of PAR2 using western blot analysis. Current responses induced by activation of TRPA1 in skeletal muscle DRG neurons were characterized using whole-cell patch clamp methods. The blood pressure response to static exercise (i.e., muscle contraction) and stimulation of TRPA1 was also examined after a blockade of PAR2. Results The expression of PAR2 was amplified in DRG neurons of the occluded limb, and PAR2 activation with SL-NH2 (a PAR2 agonist) increased the amplitude of TRPA1 currents to a greater degree in DRG neurons of the occluded limb. Moreover, FSLLRY-NH2 (a PAR antagonist) injected into the arterial blood supply of the hindlimb muscles significantly attenuated the pressor response to muscle contraction and TRPA1 stimulation in rats with occluded limbs. Conclusions The PAR2 signal in muscle sensory nerves contributes to the amplified exercise pressor reflex via TRPA1 mechanisms in rats with femoral artery ligation. These findings provide a pathophysiological basis for autonomic responses during exercise activity in PAD, which may potentially aid in the development of therapeutic approaches for improvement of blood flow in this disease. PMID:29131007

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

Fahrer, Joerg, E-mail: joerg.fahrer@uni-ulm.de; Wagner, Silvia; Buerkle, Alexander

Rapamycin is an immunosuppressive drug, which inhibits the mammalian target of rapamycin (mTOR) kinase activity inducing changes in cell proliferation. Synthesis of poly(ADP-ribose) (PAR) is an immediate cellular response to genotoxic stress catalyzed mostly by poly(ADP-ribose) polymerase 1 (PARP-1), which is also controlled by signaling pathways. Therefore, we investigated whether rapamycin affects PAR production. Strikingly, rapamycin inhibited PAR synthesis in living fibroblasts in a dose-dependent manner as monitored by immunofluorescence. PARP-1 activity was then assayed in vitro, revealing that down-regulation of cellular PAR production by rapamycin was apparently not due to competitive PARP-1 inhibition. Further studies showed that rapamycin didmore » not influence the cellular NAD pool and the activation of PARP-1 in extracts of pretreated fibroblasts. Collectively, our data suggest that inhibition of cellular PAR synthesis by rapamycin is mediated by formation of a detergent-sensitive complex in living cells, and that rapamycin may have a potential as therapeutic PARP inhibitor.« less

An optical sensor network for vegetation phenology monitoring and satellite data calibration.

PubMed

Eklundh, Lars; Jin, Hongxiao; Schubert, Per; Guzinski, Radoslaw; Heliasz, Michal

2011-01-01

We present a network of sites across Fennoscandia for optical sampling of vegetation properties relevant for phenology monitoring and satellite data calibration. The network currently consists of five sites, distributed along an N-S gradient through Sweden and Finland. Two sites are located in coniferous forests, one in a deciduous forest, and two on peatland. The instrumentation consists of dual-beam sensors measuring incoming and reflected red, green, NIR, and PAR fluxes at 10-min intervals, year-round. The sensors are mounted on separate masts or in flux towers in order to capture radiation reflected from within the flux footprint of current eddy covariance measurements. Our computations and model simulations demonstrate the validity of using off-nadir sampling, and we show the results from the first year of measurement. NDVI is computed and compared to that of the MODIS instrument on-board Aqua and Terra satellite platforms. PAR fluxes are partitioned into reflected and absorbed components for the ground and canopy. The measurements demonstrate that the instrumentation provides detailed information about the vegetation phenology and variations in reflectance due to snow cover variations and vegetation development. Valuable information about PAR absorption of ground and canopy is obtained that may be linked to vegetation productivity.

Mycosporine-like amino acid (MAAs) production by Heterocapasa sp. (Dinophyceae) in indoor cultures.

PubMed

Montero, Olimpio; Lubián, Luis M

2003-07-01

The possibility of using mycosporine-like amino acids (MAAs), with an apparent sunscreen function in nature, as ultraviolet radiation (UVR) blockers to prevent skin injury has been raised by diverse authors. Production of MAAs by the dinoflagellate Heterocapsa sp. (Dinophyceae) is shown here. Three major peaks with absorption maxima at 330.8, 332.0 and 333.2 nm were detected by high performance liquid chromatography (HPLC) analysis of methanolic extracts in all tested conditions. Analysis of crude extract by mass spectroscopy with electrospray ionization (MS-EI) showed a set of molecular ions ([M+H](+)) with main peaks being at m/z 242.4, 288.4, 303.3 and 333.3 u.m.a. According to these data, along with retention times, the MAA profile of Heterocapsa sp. is assumed to be composed of shinorine (lambda(max)=334 nm), mycosporine-2-glycine (lambda(max)=331 nm) and palythinol (lambda(max)=332 nm). A constitutive MAA content of about 4 microg (10(6) cells)(-1) was measured under exposure to PAR only. A maximal accumulation of MAA per culture volume of 1.1 mg l(-1) was obtained after 72 h of exposure to PAR+UVA, while the highest production rate (0.025 mg l(-1) h(-1)) was computed after 24 h of exposure to PAR+UVA+UVB.

An Optical Sensor Network for Vegetation Phenology Monitoring and Satellite Data Calibration

PubMed Central

Eklundh, Lars; Jin, Hongxiao; Schubert, Per; Guzinski, Radoslaw; Heliasz, Michal

2011-01-01

We present a network of sites across Fennoscandia for optical sampling of vegetation properties relevant for phenology monitoring and satellite data calibration. The network currently consists of five sites, distributed along an N-S gradient through Sweden and Finland. Two sites are located in coniferous forests, one in a deciduous forest, and two on peatland. The instrumentation consists of dual-beam sensors measuring incoming and reflected red, green, NIR, and PAR fluxes at 10-min intervals, year-round. The sensors are mounted on separate masts or in flux towers in order to capture radiation reflected from within the flux footprint of current eddy covariance measurements. Our computations and model simulations demonstrate the validity of using off-nadir sampling, and we show the results from the first year of measurement. NDVI is computed and compared to that of the MODIS instrument on-board Aqua and Terra satellite platforms. PAR fluxes are partitioned into reflected and absorbed components for the ground and canopy. The measurements demonstrate that the instrumentation provides detailed information about the vegetation phenology and variations in reflectance due to snow cover variations and vegetation development. Valuable information about PAR absorption of ground and canopy is obtained that may be linked to vegetation productivity. PMID:22164039

Trypsin impaired epithelial barrier function and induced IL-8 secretion through basolateral PAR-2: a lesson from a stratified squamous epithelial model.

PubMed

Shan, Jing; Oshima, Tadayuki; Chen, Xin; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

2012-11-15

Immune-mediated injury by the protease-activated receptor-2-interleukin-8 (PAR-2-IL8) pathway may underlie the development of gastroesophageal reflux disease (GERD). However, the localization of PAR-2 and the mechanism of PAR-2 activation remain unclear. This study aimed to address these questions on an esophageal stratified squamous epithelial model and in the human esophageal mucosa of GERD patients. Normal human esophageal epithelial cells were cultured with the air-liquid interface system to establish the model. SLIGKV-NH2 (PAR-2 synthetic agonist), trypsin (PAR-2 natural activator), and weak acid (pH 4, 5, and 6) were added to either the apical or basolateral compartment to evaluate their effects on transepithelial electrical resistance (TEER) and IL-8 production. PAR-2 localization was examined both in the cell model and biopsies from GERD patients by immunohistochemistry. Apical trypsin stimulation induced IL-8 accompanied by decreased TEER in vitro, whereas the effective concentration from the basolateral side was 10 times lower. SLIGKV-NH2 from basolateral but not apical stimulation induced IL-8 production. Apical weak acid stimulation did not influence TEER or IL-8 production. Immunohistochemistry showed intense reactivity of PAR-2 in the basal and suprabasal layers after stimulation with trypsin. A similar PAR-2 reactivity that was mainly located at the basal and suprabasal layers was detected in GERD patients. In conclusion, the activation of the PAR-2-IL-8 pathway probably occurred at the basal and suprabasal layers, while the esophageal epithelial barrier may influence the activation of PAR-2. Under proton pump inhibitor therapy, refluxed trypsin may remain active and be a potential agent in the pathogenesis of refractory GERD.

Proteinase-activated receptor (PAR)-2 activation impacts bone resorptive properties of human osteoarthritic subchondral bone osteoblasts.

PubMed

Amiable, Nathalie; Tat, Steeve Kwan; Lajeunesse, Daniel; Duval, Nicolas; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne; Boileau, Christelle

2009-06-01

In osteoarthritis (OA), the subchondral bone undergoes a remodelling process involving several factors synthesized by osteoblasts. In this study, we investigated the expression, production, modulation, and role of PAR-2 in human OA subchondral bone osteoblasts. PAR-2 expression and production were determined by real-time PCR and flow cytometry, respectively. PAR-2 modulation was investigated in OA subchondral bone osteoblasts treated with IL-1 beta (100 pg/ml), TNF-alpha (5 ng/ml), TGF-beta1 (10 ng/ml), PGE(2) (500 nM), IL-6 (10 ng/ml) and IL-17 (10 ng/ml). Membranous RANKL protein was assessed by flow cytometry, and OPG, MMP-1, MMP-9, MMP-13, IL-6 and intracellular signalling pathways by specific ELISAs. Bone resorptive activity was measured by using a co-culture model of human PBMC and OA subchondral bone osteoblasts. PAR-2 expression and production (p<0.05) were markedly increased when human OA subchondral bone osteoblasts were compared to normal. On OA osteoblasts, PAR-2 production was significantly increased by IL-1 beta, TNF-alpha and PGE(2). Activation of PAR-2 with a specific agonist, SLIGKV-NH(2), induced a significant up-regulation of MMP-1, MMP-9, IL-6, and membranous RANKL, but had no effect on MMP-13 or OPG production. Interestingly, bone resorptive activity was also significantly enhanced following PAR-2 activation. The PAR-2 effect was mediated by activation of the MAP kinases Erk1/2 and JNK. This study is the first to demonstrate that PAR-2 activation plays a role in OA subchondral bone resorption via an up-regulation of major bone remodelling factors. These results shed new light on the potential of PAR-2 as a therapeutic target in OA.

Low-temperature atomic layer deposition of CuSbS 2 for thin-film photovoltaics

DOE PAGES

Riha, Shannon C.; Koegel, Alexandra A.; Emery, Jonathan D.; ...

2017-01-24

Copper antimony sulfide (CuSbS 2) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (~1.5 eV), large absorption coefficient (>10 4 cm –1), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbS 2 thin films via atomic layer deposition has been developed. After a short (15 min) post process anneal at 225 °C, the ALD-grown CuSbS 2 films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >10 4 cm –1, as wellmore » as a hole concentration of 10 15 cm –3. Finally, the ALD-grown CuSbS 2 films were paired with ALD-grown TiO 2 to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbS 2 PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbS 2/CdS heterojunction PV devices. As a result, while far from optimized, this work demonstrates the potential for ALD-grown CuSbS 2 thin films in environmentally benign photovoltaics.« less

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures.

PubMed

Hegazy, Maha A; Lotfy, Hayam M; Mowaka, Shereen; Mohamed, Ekram Hany

2016-07-05

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Purity-activity relationships of natural products: the case of anti-TB active ursolic acid.

PubMed

Jaki, Birgit U; Franzblau, Scott G; Chadwick, Lucas R; Lankin, David C; Zhang, Fangqiu; Wang, Yuehong; Pauli, Guido F

2008-10-01

The present study explores the variability of biological responses from the perspective of sample purity and introduces the concept of purity-activity relationships (PARs) in natural product research. The abundant plant triterpene ursolic acid (1) was selected as an exemplary natural product due to the overwhelming number yet inconsistent nature of its approximate 120 reported biological activities, which include anti-TB potential. Nine different samples of ursolic acid with purity certifications were obtained, and their purity was independently assessed by means of quantitative 1H NMR (qHNMR). Biological evaluation consisted of determining MICs against two strains of virulent Mycobacterium tuberculosis and IC50 values in Vero cells. Ab initio structure elucidation provided unequivocal structural confirmation and included an extensive 1H NMR spin system analysis, determination of nearly all J couplings and the complete NOE pattern, and led to the revision of earlier reports. As a net result, a sigmoid PAR profile of 1 was obtained, demonstrating the inverse correlation of purity and anti-TB bioactivity. The results imply that synergistic effects of 1 and its varying impurities are the likely cause of previously reported antimycobacterial potential. Generating PARs is a powerful extension of the routinely performed quantitative correlation of structure and activity ([Q]SAR). Advanced by the use of primary analytical methods such as qHNMR, PARs enable the elucidation of cases like 1 when increasing purity voids biological activity. This underlines the potential of PARs as a tool in drug discovery and synergy research and accentuates the need to routinely combine biological testing with purity assessment.

Assessing the spatial and temporal variability of fAPAR 2-flux estimates in a temperate mixed coniferous forest

NASA Astrophysics Data System (ADS)

Putzenlechner, Birgitta; Sanchez-Azofeifa, Arturo; Ludwig, Ralf

2016-04-01

The fraction of absorbed photosynthetically active radiation (fAPAR) is recognized as one of the essential climate variables as it characterizes activity and dynamics of the Earth's terrestrial biosphere (GCOS, 2010). By linking photosynthetic active radiation (PAR) to the absorption of plants, fAPAR represents a crucial variable for describing land surface and atmosphere interactions considered in global circulation models as well as in production efficiency models for estimating terrestrial carbon balances. Recent studies report discrepancies between global fAPAR satellite products regarding both absolute values and uncertainty representation, thereby stressing the need for independent ground measurements (D'Odrico et al., 2014; Picket-Heaps et al., 2014; Tao et al., 2015). However, there is a lack of basic information to better understand the spatial and temporal bias of PAR field observations, particularly in forest ecosystems. In theory, it is known that fAPAR estimates are affected by e.g. illumination conditions, leaf area index, leaf color, background brightness, which in turn may lead to considerable bias of field measurements. However, theoretical findings lack validation in the field as well as practical recommendations for field protocols. In this study, the variability of two-flux fAPAR estimates with regards to different illumination conditions (solar zenith angles, diffuse radiation conditions) are investigated. Measurements of PAR are carried out at Graswang environmental monitoring site in Southern Germany within a temperate mixed coniferous forest. A relatively new environmental monitoring technology based on Wireless Sensor Networks (WSN) is applied, allowing for permanent synchronized measurements of transmitted PAR, thereby reducing temporal sampling bias. Transmitted PAR is obtained from 16 photon flux sensors, 1.3 m above the surface. With a reference sensor outside the forest measuring incoming PAR, a two-flux estimate based on the ratio of transmitted PAR and incoming PAR can be calculated for each 10-min timestep during daytime hours. The fAPAR time series exhibit seasonal variability (mean=0.7, sd=0.4 for the average of all PAR sensors calculated for each 10-min timestep) according to phenological development, but also considerable inter-sensor variability between single days. Standard deviations for fAPAR in mid-summer vary between 0.26 for days with overcast sky and 0.19 for clear sky conditions. Diurnal cycles of fAPAR under clear sky conditions show a sharp increase of fAPAR with increasing solar zenith angles, suggesting for an underestimation of fAPAR with low solar zenith angles as it has also been found in studies based on radiative transfer modeling (Widlowski et al., 2010). The experiences gained from the field observations contribute to a bias assessment for ground measurements as demanded by authors of recent studies on comparing global fAPAR satellite products.

Leukemia inhibitory factor promote trophoblast invasion via urokinase-type plasminogen activator receptor in preeclampsia.

PubMed

Zheng, Qin; Dai, Kuixing; Cui, Xinyuan; Yu, Ming; Yang, Xuesong; Yan, Bin; Liu, Shuai; Yan, Qiu

2016-05-01

Preeclampsia is a pregnancy-related syndrome which can cause perinatal mortality and morbidity. Inadequate invasion by trophoblast cells may lead to poor perfusion of the placenta, even result in preeclampsia. Understanding the molecular mechanisms underlying placentation facilitates the better intervention of preeclampsia. Urokinase-type plasminogen activator receptor (uPAR) is involved in the physiological and pathological processes. Leukemia inhibitory factor (LIF) is an important regulator in the establishment of pregnancy. However, the expression of uPAR in preeclamptic patients and its relationship with LIF remains unclear. In the current study, we found that the level of uPAR was relatively lower in the placentas from preeclamptic patients as compared with normal pregnant women. LIF promoted trophoblast cell outgrowth by upregulating uPAR in an explants culture, and LIF also enhanced migration and invasion potential through uPAR in trophoblast JAR and JEG-3 cell lines, and with increased gelatinolytic activities of matrix metalloproteinase 2 (MMP-2). The effect of LIF and uPAR on trophoblast migration and invasion was mediated by PI3K/AKT signaling pathway. Our data indicates the roles of LIF in promoting trophoblast migration and invasion through uPAR and suggest that abnormal expression of uPAR might be associated with the etiology of preeclampsia. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Molecular networks implicated in speech-related disorders: FOXP2 regulates the SRPX2/uPAR complex.

PubMed

Roll, Patrice; Vernes, Sonja C; Bruneau, Nadine; Cillario, Jennifer; Ponsole-Lenfant, Magali; Massacrier, Annick; Rudolf, Gabrielle; Khalife, Manal; Hirsch, Edouard; Fisher, Simon E; Szepetowski, Pierre

2010-12-15

It is a challenge to identify the molecular networks contributing to the neural basis of human speech. Mutations in transcription factor FOXP2 cause difficulties mastering fluent speech (developmental verbal dyspraxia, DVD), whereas mutations of sushi-repeat protein SRPX2 lead to epilepsy of the rolandic (sylvian) speech areas, with DVD or with bilateral perisylvian polymicrogyria. Pathophysiological mechanisms driven by SRPX2 involve modified interaction with the plasminogen activator receptor (uPAR). Independent chromatin-immunoprecipitation microarray screening has identified the uPAR gene promoter as a potential target site bound by FOXP2. Here, we directly tested for the existence of a transcriptional regulatory network between human FOXP2 and the SRPX2/uPAR complex. In silico searches followed by gel retardation assays identified specific efficient FOXP2-binding sites in each of the promoter regions of SRPX2 and uPAR. In FOXP2-transfected cells, significant decreases were observed in the amounts of both SRPX2 (43.6%) and uPAR (38.6%) native transcripts. Luciferase reporter assays demonstrated that FOXP2 expression yielded a marked inhibition of SRPX2 (80.2%) and uPAR (77.5%) promoter activity. A mutant FOXP2 that causes DVD (p.R553H) failed to bind to SRPX2 and uPAR target sites and showed impaired down-regulation of SRPX2 and uPAR promoter activity. In a patient with polymicrogyria of the left rolandic operculum, a novel FOXP2 mutation (p.M406T) was found in the leucine-zipper (dimerization) domain. p.M406T partially impaired the FOXP2 regulation of SRPX2 promoter activity, whereas that of the uPAR promoter remained unchanged. Together with recently described FOXP2-CNTNAP2 and SRPX2/uPAR links, the FOXP2-SRPX2/uPAR network provides exciting insights into molecular pathways underlying speech-related disorders.

Forced-flow chromatographic determination of calcium and magnesium with continuous spectrophotometric detection

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

Arguello, M.D.

1977-12-01

Modifications to the forced-flow chromatograph include a flow-through pH monitor to continuously monitor the pH of the final effluent and an active low-pass filter to eliminate noise in the spectrophotometric detector. All separations are performed using partially sulfonated XAD-2 as the ion exchanger. Elution of calcium and magnesium is accomplished using ammonium chloride and ethylenediammonium chloride solutions. Calcium and magnesium are detected by means of Arsenazo I and PAR-ZnEDTA color-forming reagents. Other metal ions are detected by means of PAR and Chromazurol S color-forming reagents. Calcium and magnesium distribution coefficients on partially sulfonated XAD-2 as functions of ammonium chloride andmore » ethylenediammonium chloride concentration are given together with distribution coefficients of other metal ions. Methods for the selective elution of interfering metal ions prior to the elution of calcium and magnesium are described. Beryllium and aluminum are selectively eluted with sulfosalicylic acid. Those elements forming anionic chloride complexes are selectively eluted with HCl-acetone. Nickel is selectively eluted with HCl-acetone-dimethylglyoxime. Synthetic samples containing calcium and magnesium, both alone and in combination with alkali metals, strontium, barium, beryllium, aluminum, transition metals, and rare earths, are analyzed. Hard water samples are analyzed for calcium and magnesium and the results compared to those obtained by EDTA titration, atomic absorption spectroscopy, and plasma emission spectroscopy. Several clinical serum samples are analyzed for calcium and magnesium and the results compared to those obtained by atomic absorption spectroscopy.« less

Mesoscale variation in the photophysiology of the reef building coral Pocillopora damicornis along an environmental gradient

NASA Astrophysics Data System (ADS)

Cooper, Timothy F.; Ulstrup, Karin E.

2009-06-01

Spatial variation in the photophysiology of symbiotic dinoflagellates (zooxanthellae) of the scleractinian coral Pocillopora damicornis was examined along an environmental gradient in the Whitsunday Islands (Great Barrier Reef) at two depths (3 m and 6 m). Chlorophyll a fluorescence of photosystem II (PSII) and PAR-absorptivity measurements were conducted using an Imaging-PAM (pulse-amplitude-modulation) fluorometer. Most photophysiological parameters correlated with changes in environmental conditions quantified by differences in water quality along the gradient. For example, maximum quantum yield ( Fv/ Fm) increased and PAR-absorptivity decreased as water quality improved along the gradient from nearshore reefs (low irradiance, elevated nutrients and sediments) to outer islands (high irradiance, low nutrients and sediments). For apparent photosynthetic rate (PS max) and minimum saturating irradiance ( Ek), the direction of change differed depending on sampling depth, suggesting that different mechanisms of photo-acclimatisation operated between shallow and deep corals. Deep corals conformed to typical patterns of light/shade acclimatisation whereas shallow corals exhibited reduced PS max and Ek with improving water quality coinciding with greater heat dissipation (NPQ 241). Furthermore, deep corals on nearshore reefs exhibited elevated Q241 in comparison to outer islands possibly due to effects of sedimentation and/or pollutants rather than irradiance. These results highlight the importance of mesoscale sampling to obtain useful estimates of the variability of photophysiological parameters, particularly if such measures are to be used as bioindicators of the condition of coral reefs.

High density of tryptase-positive mast cells in human colorectal cancer: a poor prognostic factor related to protease-activated receptor 2 expression

PubMed Central

Malfettone, Andrea; Silvestris, Nicola; Saponaro, Concetta; Ranieri, Girolamo; Russo, Antonio; Caruso, Stefano; Popescu, Ondina; Simone, Giovanni; Paradiso, Angelo; Mangia, Anita

2013-01-01

Tryptase(+) mast cells (MCs), abundant in the invasive front of tumours, contribute to tissue remodelling. Indeed, protease-activated receptor-2 (PAR-2) activation by MC-tryptase is considered an oncogenic event in colorectal cancer (CRC). Recently, we have suggested NHERF1 as a potential new marker in CRC. In this study, we aimed to determine the distribution of tryptase(+) MCs and PAR-2 and to examine the relationship between PAR-2 and NHERF1, investigating their reputed usefulness as tumour markers. We studied a cohort of 115 CRC specimens including primary cancer (C) and adjacent normal mucosa (NM) by immunohistochemical double staining, analyzing the protein expression of MC-tryptase, PAR-2 and cytoplasmic NHERF1. MC density was higher in NM than in C. Tumours with high TNM stage and poor grade showed the highest MC density. A higher PAR-2 immunoreactivity characterized tumours most infiltrated by MCs compared with samples with low MC density. Furthermore, PAR-2 overexpression was associated with advanced TNM stage, poor grade and lymphovascular invasion (LVI). A positive correlation existed between tryptase(+) MC density and PAR-2 expression. Cytoplasmic NHERF1 was higher in C than in NM and overexpressing tumours resulted associated with nodal and distant metastases, poor grade and LVI. PAR-2 correlated with cytoplasmic NHERF1 and the PAR-2(+)/cytoplasmic NHERF1(+) expression immunophenotype identified tumours associated with unfavourable prognosis and aggressive clinical parameters. Our data indicate that the high density of tryptase(+) MCs at invasive margins of tumours was associated with advanced stages of CRC and was strongly correlated with PAR-2 expression. PMID:23991686

Lesioning of TRPV1 Expressing Primary Afferent Neurons Prevents PAR-2 Induced Motility, but Not Mechanical Hypersensitivity in the Rat Colon

PubMed Central

Suckow, Shelby K.; Anderson, Ethan M.; Caudle, Robert M.

2011-01-01

Background Proteinase activated receptor 2 (PAR-2) is expressed by many neurons in the colon, including primary afferent neurons that co-express transient receptor potential vanilloid 1 (TRPV1). Activation of PAR-2 receptors was previously found to enhance colonic motility, increase secretion and produce hypersensitivity to mechanical stimuli. This study examined the functional role of TRPV1/PAR-2 expressing neurons that innervate the colon by lesioning TRPV1 bearing neurons with the highly selective and potent TRPV1 agonist resiniferatoxin. Methods Colonic motility in response to PAR-2 activation was evaluated in vitro using isolated segments of descending colon and in vivo using manometry. Colonic mechanical nociceptive thresholds were measured using colorectal distension. TRPV1 expressing neurons were selectively lesioned with resiniferatoxin. Key Results In vitro the PAR-2 agonists trypsin and SLIGRL did not alter contractions of colon segments when applied alone, however, the agents enhanced acetylcholine stimulated contraction. In vivo, PAR-2 agonists administered intraluminally induced contractions of the colon and produced hypersensitivity to colorectal distention. The PAR-2 agonist enhancement of colonic contraction was eliminated when TRPV1 expressing neurons were lesioned with resiniferatoxin, but the PAR-2 agonist induced hypersensitivity remained in the lesioned animals. Conclusions and Inferences Our findings indicate that TRPV1/PAR-2 expressing primary afferent neurons mediate an extrinsic motor reflex pathway in the colon. These data, coupled with our previous studies, also indicate that the recently described colospinal afferent neurons are nociceptive, suggesting that these neurons may be useful targets for the pharmacological control of pain in diseases such as irritable bowel syndrome. PMID:22168801

Plasma suPAR as a prognostic biological marker for ICU mortality in ARDS patients.

PubMed

Geboers, Diederik G P J; de Beer, Friso M; Tuip-de Boer, Anita M; van der Poll, Tom; Horn, Janneke; Cremer, Olaf L; Bonten, Marc J M; Ong, David S Y; Schultz, Marcus J; Bos, Lieuwe D J

2015-07-01

We investigated the prognostic value of plasma soluble urokinase plasminogen activator receptor (suPAR) on day 1 in patients with the acute respiratory distress syndrome (ARDS) for intensive care unit (ICU) mortality and compared it with established disease severity scores on day 1. suPAR was determined batchwise in plasma obtained within 24 h after admission. 632 ARDS patients were included. Significantly (P = 0.02) higher median levels of suPAR were found with increasing severity of ARDS: 5.9 ng/ml [IQR 3.1-12.8] in mild ARDS (n = 82), 8.4 ng/ml [IQR 4.1-15.0] in moderate ARDS (n = 333), and 9.0 ng/ml [IQR 4.5-16.0] in severe ARDS (n = 217). Non-survivors had higher median levels of suPAR [12.5 ng/ml (IQR 5.1-19.5) vs. 7.4 ng/ml (3.9-13.6), P < 0.001]. The area under the receiver operator characteristic curve (ROC-AUC) for mortality of suPAR (0.62) was lower than the ROC-AUC of the APACHE IV score (0.72, P = 0.007), higher than that of the ARDS definition classification (0.53, P = 0.005), and did not differ from that of the SOFA score (0.68, P = 0.07) and the oxygenation index (OI) (0.58, P = 0.29). Plasma suPAR did not improve the discrimination of the established disease severity scores, but did improve net reclassification of the APACHE score (29%), SOFA score (23%), OI (38%), and Berlin definition classification (39%). As a single biological marker, the prognostic value for death of plasma suPAR in ARDS patients is low. Plasma suPAR, however, improves the net reclassification, suggesting a potential role for suPAR in ICU mortality prediction models.

Financial impact of introducing the Swiss-DRG reimbursement system on potentially avoidable readmissions at a university hospital.

PubMed

Wasserfallen, Jean-Blaise; Zufferey, Jade

2015-01-01

Thirty-day readmissions can be classified as potentially avoidable (PARs) or not avoidable (NARs) by following a specific algorithm (SQLape®). We wanted to assess the financial impact of the Swiss-DRG system, which regroups some readmissions occurring within 18 days after discharge within the initial hospital stay, on PARs at our hospital. First, PARs were identified from all hospitalisations recorded in 2011 at our university hospital. Second, 2012 Swiss-DRG readmission rules were applied, regrouped readmissions (RR) were identified, and their financial impact computed. Third, RRs were classified as potentially avoidable (PARRs), not avoidable (NARRs), and others causes (OCRRs). Characteristics of PARR patients and stays were retrieved, and the financial impact of PARRS was computed. A total of 36,777 hospitalisations were recorded in 2011, of which 3,140 were considered as readmissions (8.5%): 1,470 PARs (46.8%) and 1,733 NARs (53.2%). The 2012 Swiss-DRG rules would have resulted in 910 RRs (2.5% of hospitalisations, 29% of readmissions): 395 PARRs (43% of RR), 181 NARRs (20%), and 334 OCRRs (37%). Loss in reimbursement would have amounted to CHF 3.157 million (0.6% of total reimbursement). As many as 95% of the 395 PARR patients lived at home. In total, 28% of PARRs occurred within 3 days after discharge, and 58% lasted less than 5 days; 79% of the patients were discharged home again. Loss in reimbursement would amount to CHF 1.771 million. PARs represent a sizeable number of 30-day readmissions, as do PARRs of 18-day RRs in the 2012 Swiss DRG system. They should be the focus of attention, as the PARRs represent an avoidable loss in reimbursement.

Resveratrol inhibits proteinase-activated receptor-2-induced release of soluble vascular endothelial growth factor receptor-1 from human endothelial cells

PubMed Central

Al-Ani, Bahjat

2013-01-01

We recently reported that (i) activation of the proinflammatory receptor, proteinase-activated receptor-2 (PAR-2) caused the release of an important biomarker in preeclampsia, soluble vascular endothelial growth factor receptor-1 (sVEGFR-1, also known as sFlt-1) from human umbilical vein endothelial cells (HUVECs), and (ii) that the anti-oxidant and anti-inflammatory agent, resveratrol, is capable of inhibiting the proinflammatory cytokine-induced sVEGFR-1 release from human placenta. Based on these findings and because PAR-2 is upregulated by proinflammatory cytokines, we sought to determine whether resveratrol can inhibit PAR-2-induced sVEGFR-1 release. PAR-2 expressing cells, HUVECs and human embryonic kidney cells (HEK-293) transfected with a human VEGFR-1 promoter-luciferase reporter construct were incubated with PAR-2-activating peptide and/or resveratrol. Cell supernatants were assayed for sVEGFR-1 by enzyme-linked immunosorbent assay (ELISA), and VEGFR-1 promoter-luciferase assay was performed on the harvested cell lysates. Preincubation of HEK-293 cells with resveratrol significantly inhibited PAR-2-induced VEGFR-1 promoter activity without affecting cell viability as assessed by MTT assay. The addition of resveratrol also blocked PAR-2-mediated sVEGFR-1 release from HUVECs. The present study demonstrates that resveratrol suppressed both VEGFR-1 promoter activity and sVEGFR-1 protein release induced by PAR-2 activation, which further endorses our recent findings of a potential therapeutic role for resveratrol in preeclampsia. PMID:26933402

Activation of PAR(2) receptors sensitizes primary afferents and causes leukocyte rolling and adherence in the rat knee joint.

PubMed

Russell, F A; Schuelert, N; Veldhoen, V E; Hollenberg, M D; McDougall, J J

2012-12-01

The PAR(2) receptors are involved in chronic arthritis by mechanisms that are as yet unclear. Here, we examined PAR(2) activation in the rat knee joint. PAR(2) in rat knee joint dorsal root ganglia (DRG) cells at L3-L5, retrogradely labelled with Fluoro-gold (FG) were demonstrated immunohistochemically. Electrophysiological recordings from knee joint nerve fibres in urethane anaesthetized Wistar rats assessed the effects of stimulating joint PAR(2) with its activating peptide, 2-furoyl-LIGRLO-NH(2) (1-100 nmol·100 μL(-1) , via close intra-arterial injection). Fibre firing rate was recorded during joint rotations before and 15 min after administration of PAR(2) activating peptide or control peptide. Leukocyte kinetics in the synovial vasculature upon PAR(2) activation were followed by intravital microscopy for 60 min after perfusion of 2-furoyl-LIGRLO-NH(2) or control peptide. Roles for transient receptor potential vanilloid-1 (TRPV1) or neurokinin-1 (NK(1) ) receptors in the PAR(2) responses were assessed using the selective antagonists, SB366791 and RP67580 respectively. PAR(2) were expressed in 59 ± 5% of FG-positive DRG cells; 100 nmol 2-furoyl-LIGRLO-NH(2) increased joint fibre firing rate during normal and noxious rotation, maximal at 3 min (normal; 110 ± 43%, noxious; 90 ± 31%). 2-Furoyl-LIGRLO-NH(2) also significantly increased leukocyte rolling and adhesion over 60 min. All these effects were blocked by pre-treatment with SB366791 and RP67580 (P < 0.05 compared with 2-furoyl-LIGRLO-NH(2) alone). PAR(2) receptors play an acute inflammatory role in the knee joint via TRPV1- and NK(1) -dependent mechanisms involving both PAR(2) -mediated neuronal sensitization and leukocyte trafficking. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

Tumor Penetrating Theranostic Nanoparticles for Enhancement of Targeted and Image-guided Drug Delivery into Peritoneal Tumors following Intraperitoneal Delivery.

PubMed

Gao, Ning; Bozeman, Erica N; Qian, Weiping; Wang, Liya; Chen, Hongyu; Lipowska, Malgorzata; Staley, Charles A; Wang, Y Andrew; Mao, Hui; Yang, Lily

2017-01-01

The major obstacles in intraperitoneal (i.p.) chemotherapy of peritoneal tumors are fast absorption of drugs into the blood circulation, local and systemic toxicities, inadequate drug penetration into large tumors, and drug resistance. Targeted theranostic nanoparticles offer an opportunity to enhance the efficacy of i.p. therapy by increasing intratumoral drug delivery to overcome resistance, mediating image-guided drug delivery, and reducing systemic toxicity. Herein we report that i.p. delivery of urokinase plasminogen activator receptor (uPAR) targeted magnetic iron oxide nanoparticles (IONPs) led to intratumoral accumulation of 17% of total injected nanoparticles in an orthotopic mouse pancreatic cancer model, which was three-fold higher compared with intravenous delivery. Targeted delivery of near infrared dye labeled IONPs into orthotopic tumors could be detected by non-invasive optical and magnetic resonance imaging. Histological analysis revealed that a high level of uPAR targeted, PEGylated IONPs efficiently penetrated into both the peripheral and central tumor areas in the primary tumor as well as peritoneal metastatic tumor. Improved theranostic IONP delivery into the tumor center was not mediated by nonspecific macrophage uptake and was independent from tumor blood vessel locations. Importantly, i.p. delivery of uPAR targeted theranostic IONPs carrying chemotherapeutics, cisplatin or doxorubicin, significantly inhibited the growth of pancreatic tumors without apparent systemic toxicity. The levels of proliferating tumor cells and tumor vessels in tumors treated with the above theranostic IONPs were also markedly decreased. The detection of strong optical signals in residual tumors following i.p. therapy suggested the feasibility of image-guided surgery to remove drug-resistant tumors. Therefore, our results support the translational development of i.p. delivery of uPAR-targeted theranostic IONPs for image-guided treatment of peritoneal tumors.

Effects of Whitecaps on Satellite-Derived Ocean Color

NASA Technical Reports Server (NTRS)

Frouin, Robert

2000-01-01

During the 3.25 years of the project, various aspects of satellite ocean-color remote sensing were investigated, including effect of whitecaps on atmospheric correction, validity of aerosol models, and evaluation of ocean-color products. Algorithms to estimate pigment concentration and photo-synthetically active radiation (PAR) were developed, and studies of geophysical phenomena, such as the 1998 Asian Dust event, were performed. The influence of solar radiation absorption by phytoplankton on mixed layer dynamics, ocean circulation, and climate was also investigated. The project's results and findings are described.

Direct Measurements of Leaf Level CH4 and CO2 Exchange in a Boreal Forest

NASA Astrophysics Data System (ADS)

Crill, P.; Lindroth, A.; Vestin, P.; Båth, A.

2008-12-01

Reports of aerobic CH4 sources from leaves and litter of a variety of forests and plant functional types have added a potential mystery to our understanding of CH4 dynamics especially if these sources contribute enough to have a significant impact on the global budget. We have made direct measurements of leaf level CH4 and CO2 exchange using a quartz branch cuvette in a boreal forest in Norunda, Sweden since August of this year. The cuvette was temperature controlled and was designed to close for 5 minutes every 30 minutes. Air was circulated to a Los Gatos CH4/CO2 infrared absorption laser spectrometer. Air and cuvette temperatures, PAR and UV radiation (Kipp and Zonen, CUV4; spectral range 300-380 nm) were measured at the branch chamber. The study was made in the Norunda 100 years old stand consisting of a mixture of Scots pine (Pinus sylvestris L.) , Birch (Betula sp.) and Norway spruce (Picea abies (L.) Karst.). The cuvette was moved between trees at roughly 5 day intervals. A null empty cuvette period was included in the rotation. The initial data show the expected CO2 uptake correlated with incident PAR and low rates of emission at night. However, there was no clear pattern of emissions detectable in the CH4. We estimate that we should be able to resolve a change of 0.5 ppbv CH4 min- 1 with our analytical setup. Both the daytime (1000-1600) and nighttime (2200-0400) averages were less than our detection. Even on very sunny days with high PAR and UV flux values, no consistent pattern was detectable. The lack of a distinct signal may be due to the fact that the past month has been very rainy, it is late in the growth season at these latitudes and sun angles are increasing quickly. The trees were at the northern edge of a clearing and we were also measuring mid height (2-3 m) leaves and branches of young trees. The branch cuvette design can also be optimized to improve its sensitivity.

Potential of solar-induced chlorophyll fluorescence to estimate transpiration in a temperate forest

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

Lu, Xiaoliang; Liu, Zhunqiao; An, Shuqing

By utilizing continuous measurements of water fluxes and solar-induced chlorophyll fluorescence (SIF) over the entire growing season, we exploit the potential of broadband SIF in predicting plant transpiration (T) in a temperate forest. After reconstructing the full SIF spectrum from the selected absorption lines and simulations from the SCOPE (Soil Canopy Observation Photochemistry and Energy fluxes) model, linear regression (LR) and Gaussian processes regression (GPR) models are used to analyze the relation between T and combinations of different SIF bands. We find that SIF emissions in the near-infrared spectrum (at 720 nm, 740 nm and 760 nm) are more sensitivemore » to T than SIF emissions in the red spectrum (at 685 nm and 687 nm). While conditions such as light and heat stress decouple the relationship between single-band SIF and T, the combination of different SIF bands allows the retrieval of reliable T estimates even in these conditions. Overall, we find that the use of SIF as a proxy for T yields estimates that are at least as accurate as those from traditional transpiration models such as the Penman-Monteith equation, which are input demanding and complex to apply to in situ and satellite data. Specifically, we find that (1) the SIF-T relationship deteriorates when Photosynthetically Active Radiation (PAR), vapor pressure deficit and air temperature exceed biological optimal thresholds; (2) a high leaf area index exerts a negative impact on the SIF-T correlation due to increasing scattering and (re)absorption of the SIF signal; (3) the SIF-T relationship does not change depending on the observation time during the day; and (4) temporal aggregation to days further enhanced the SIF-T correlations. Altogether, our results provide the first ground-based evidence that SIF emission has potential to be a close predictor of plant transpiration, especially when a combination of different SIF bands is considered.« less

Satellite estimation of incident photosynthetically active radiation using ultraviolet reflectance

NASA Technical Reports Server (NTRS)

Eck, Thomas F.; Dye, Dennis G.

1991-01-01

A new satellite remote sensing method for estimating the amount of photosynthetically active radiation (PAR, 400-700 nm) incident at the earth's surface is described and tested. Potential incident PAR for clear sky conditions is computed from an existing spectral model. A major advantage of the UV approach over existing visible band approaches to estimating insolation is the improved ability to discriminate clouds from high-albedo background surfaces. UV spectral reflectance data from the Total Ozone Mapping Spectrometer (TOMS) were used to test the approach for three climatically distinct, midlatitude locations. Estimates of monthly total incident PAR from the satellite technique differed from values computed from ground-based pyranometer measurements by less than 6 percent. This UV remote sensing method can be applied to estimate PAR insolation over ocean and land surfaces which are free of ice and snow.

A Changing Arctic Sea Ice Cover and the Partitioning of Solar Radiation

NASA Astrophysics Data System (ADS)

Perovich, D. K.; Light, B.; Polashenski, C.; Nghiem, S. V.

2010-12-01

Certain recent changes in the Arctic sea ice cover are well established. There has been a reduction in sea ice extent, an overall thinning of the ice cover, reduced prevalence of perennial ice with accompanying increases in seasonal ice, and a lengthening of the summer melt season. Here we explore the effects of these changes on the partitioning of solar energy between reflection to the atmosphere, absorption within the ice, and transmission to the ocean. The physical changes in the ice cover result in less light reflected and more light absorbed in the ice and transmitted to the ocean. These changes directly affect the heat and mass balance of the ice as well as the amount of light available for photosynthesis within and beneath the ice cover. The central driver is that seasonal ice covers tend to have lower albedo than perennial ice throughout the melt season, permitting more light to penetrate into the ice and ocean. The enhanced light penetration increases the amount of internal melting of the ice and the heat content of the upper ocean. The physical changes in the ice cover mentioned above have affected both the amount and the timing of the photosynthetically active radiation (PAR) transmitted into the ice and ocean, increasing transmitted PAR, particularly in the spring. A comparison of the partitioning of solar irradiance and PAR for both historical and recent ice conditions will be presented.

Variability of Solar Radiation and CDOM in Surface Coastal Waters of the Northwestern Mediterranean Sea.

PubMed

Sempéré, Richard; Para, Julien; Tedetti, Marc; Charrière, Bruno; Mallet, Marc

2015-01-01

Atmospheric and in-water solar radiation, including UVR-B, UVR-A and PAR, as well as chromophoric dissolved organic matter absorption [aCDOM (λ)] in surface waters were monthly measured from November 2007 to December 2008 at a coastal station in the Northwestern Mediterranean Sea (Bay of Marseilles, France). Our results showed that the UVR-B/UVR-A ratio followed the same trend in the atmosphere and at 2 m depth in the water (P < 0.0001) with an increase (eight-fold higher) during summer. The low diffuse attenuation coefficients for downward irradiance [Kd (λ)] of UVR-B, UVR-A and PAR indicated that the waters were highly transparent throughout the year. The relationships between aCDOM (λ) and Kd (λ) in this oligotrophic system suggested that CDOM contributed to UVR attenuation in the UVA domain, but also played a significant role in PAR attenuation. Mean UV doses received in the mixed layer depth were higher by a factor 1.4-33 relative to doses received at fixed depths (5 and 10 m) in summer (stratified period), while the inverse pattern was found in winter (mixing period). This shows the importance of taking into account the vertical mixing in the evaluation of UVR effects on marine organisms. © 2015 The American Society of Photobiology.

Fully human antibodies against the Protease-Activated Receptor-2 (PAR-2) with anti-inflammatory activity.

PubMed

Giblin, Patricia; Boxhammer, Rainer; Desai, Sudha; Kroe-Barrett, Rachel; Hansen, Gale; Ksiazek, John; Panzenbeck, Maret; Ralph, Kerry; Schwartz, Racheline; Zimmitti, Clare; Pracht, Catrin; Miller, Sandra; Magram, Jeanne; Litzenburger, Tobias

2011-01-01

PAR-2 belongs to a family of G-protein coupled Protease-Activated Receptors (PAR) which are activated by specific proteolytic cleavage in the extracellular N-terminal region. PAR-2 is activated by proteases such as trypsin, tryptase, proteinase 3, factor VIIa, factor Xa and is thought to be a mediator of inflammation and tissue injury, where elevated levels of proteases are found. Utilizing the HuCAL GOLD® phage display library we generated fully human antibodies specifically blocking the protease cleavage site in the N-terminal domain. In vitro affinity optimization resulted in antibodies with up to 1000-fold improved affinities relative to the original parental antibodies with dissociation constants as low as 100 pM. Corresponding increases in potency were observed in a mechanistic protease cleavage assay. The antibodies effectively inhibited PAR-2 mediated intracellular calcium release and cytokine secretion in various cell types stimulated with trypsin. In addition, the antibodies demonstrated potent inhibition of trypsin induced relaxation of isolated rat aortic rings ex vivo. In a short term mouse model of inflammation, the trans vivo DTH model, anti-PAR-2 antibodies showed inhibition of the inflammatory swelling response. In summary, potent inhibitors of PAR-2 were generated which allow further assessment of the role of this receptor in inflammation and evaluation of their potential as therapeutic agents.

Estimation of the fraction of absorbed photosynthetically active radiation (fPAR) in maize canopies using LiDAR data and hyperspectral imagery.

PubMed

Qin, Haiming; Wang, Cheng; Zhao, Kaiguang; Xi, Xiaohuan

2018-01-01

Accurate estimation of the fraction of absorbed photosynthetically active radiation (fPAR) for maize canopies are important for maize growth monitoring and yield estimation. The goal of this study is to explore the potential of using airborne LiDAR and hyperspectral data to better estimate maize fPAR. This study focuses on estimating maize fPAR from (1) height and coverage metrics derived from airborne LiDAR point cloud data; (2) vegetation indices derived from hyperspectral imagery; and (3) a combination of these metrics. Pearson correlation analyses were conducted to evaluate the relationships among LiDAR metrics, hyperspectral metrics, and field-measured fPAR values. Then, multiple linear regression (MLR) models were developed using these metrics. Results showed that (1) LiDAR height and coverage metrics provided good explanatory power (i.e., R2 = 0.81); (2) hyperspectral vegetation indices provided moderate interpretability (i.e., R2 = 0.50); and (3) the combination of LiDAR metrics and hyperspectral metrics improved the LiDAR model (i.e., R2 = 0.88). These results indicate that LiDAR model seems to offer a reliable method for estimating maize fPAR at a high spatial resolution and it can be used for farmland management. Combining LiDAR and hyperspectral metrics led to better performance of maize fPAR estimation than LiDAR or hyperspectral metrics alone, which means that maize fPAR retrieval can benefit from the complementary nature of LiDAR-detected canopy structure characteristics and hyperspectral-captured vegetation spectral information.

Phytoplankton absorption predicts patterns in primary productivity in Australian coastal shelf waters

NASA Astrophysics Data System (ADS)

Robinson, C. M.; Cherukuru, N.; Hardman-Mountford, N. J.; Everett, J. D.; McLaughlin, M. J.; Davies, K. P.; Van Dongen-Vogels, V.; Ralph, P. J.; Doblin, M. A.

2017-06-01

The phytoplankton absorption coefficient (aPHY) has been suggested as a suitable alternate first order predictor of net primary productivity (NPP). We compiled a dataset of surface bio-optical properties and phytoplankton NPP measurements in coastal waters around Australia to examine the utility of an in-situ absorption model to estimate NPP. The magnitude of surface NPP (0.20-19.3 mmol C m-3 d-1) across sites was largely driven by phytoplankton biomass, with higher rates being attributed to the microplankton (>20 μm) size class. The phytoplankton absorption coefficient aPHY for PAR (photosynthetically active radiation; āPHY)) ranged from 0.003 to 0.073 m-1, influenced by changes in phytoplankton community composition, physiology and environmental conditions. The aPHY coefficient also reflected changes in NPP and the absorption model-derived NPP could explain 73% of the variability in measured surface NPP (n = 41; RMSE = 2.49). The absorption model was applied to two contrasting coastal locations to examine NPP dynamics: a high chlorophyll-high variation (HCHV; Port Hacking National Reference Station) and moderate chlorophyll-low variation (MCLV; Yongala National Reference Station) location in eastern Australia using the GIOP-DC satellite aPHY product. Mean daily NPP rates between 2003 and 2015 were higher at the HCHV site (1.71 ± 0.03 mmol C m-3 d-1) with the annual maximum NPP occurring during the austral winter. In contrast, the MCLV site annual NPP peak occurred during the austral wet season and had lower mean daily NPP (1.43 ± 0.03 mmol C m-3 d-1) across the time-series. An absorption-based model to estimate NPP is a promising approach for exploring the spatio-temporal dynamics in phytoplankton NPP around the Australian continental shelf.

Activation of Protease Activated Receptor 2 by Exogenous Agonist Exacerbates Early Radiation Injury in Rat Intestine

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

Wang Junru; Boerma, Marjan; Kulkarni, Ashwini

2010-07-15

Purpose: Protease-activated receptor-2 (PAR{sub 2}) is highly expressed throughout the gut and regulates the inflammatory, mitogenic, fibroproliferative, and nociceptive responses to injury. PAR{sub 2} is strikingly upregulated and exhibits increased activation in response to intestinal irradiation. We examined the mechanistic significance of radiation enteropathy development by assessing the effect of exogenous PAR{sub 2} activation. Methods and Materials: Rat small bowel was exposed to localized single-dose radiation (16.5 Gy). The PAR{sub 2} agonist (2-furoyl-LIGRLO-NH{sub 2}) or vehicle was injected intraperitoneally daily for 3 days before irradiation (before), for 7 days after irradiation (after), or both 3 days before and 7 daysmore » after irradiation (before-after). Early and delayed radiation enteropathy was assessed at 2 and 26 weeks after irradiation using quantitative histologic examination, morphometry, and immunohistochemical analysis. Results: The PAR{sub 2} agonist did not elicit changes in the unirradiated (shielded) intestine. In contrast, in the irradiated intestine procured 2 weeks after irradiation, administration of the PAR{sub 2} agonist was associated with more severe mucosal injury and increased intestinal wall thickness in all three treatment groups (p <.05) compared with the vehicle-treated controls. The PAR{sub 2} agonist also exacerbated the radiation injury score, serosal thickening, and mucosal inflammation (p <.05) in the before and before-after groups. The short-term exogenous activation of PAR{sub 2} did not affect radiation-induced intestinal injury at 26 weeks. Conclusion: The results of the present study support a role for PAR{sub 2} activation in the pathogenesis of early radiation-induced intestinal injury. Pharmacologic PAR{sub 2} antagonists might have the potential to reduce the intestinal side effects of radiotherapy and/or as countermeasures in radiologic accidents or terrorism scenarios.« less

Caracterisation des proprietes acoustiques des materiaux poreux a cellules ouvertes et a matrice rigide ou souple

NASA Astrophysics Data System (ADS)

Salissou, Yacoubou

L'objectif global vise par les travaux de cette these est d'ameliorer la caracterisation des proprietes macroscopiques des materiaux poreux a structure rigide ou souple par des approches inverses et indirectes basees sur des mesures acoustiques faites en tube d'impedance. La precision des approches inverses et indirectes utilisees aujourd'hui est principalement limitee par la qualite des mesures acoustiques obtenues en tube d'impedance. En consequence, cette these se penche sur quatre problemes qui aideront a l'atteinte de l'objectif global precite. Le premier probleme porte sur une caracterisation precise de la porosite ouverte des materiaux poreux. Cette propriete en est une de passage permettant de lier la mesure des proprietes dynamiques acoustiques d'un materiau poreux aux proprietes effectives de sa phase fluide decrite par les modeles semi-phenomenologiques. Le deuxieme probleme traite de l'hypothese de symetrie des materiaux poreux selon leur epaisseur ou un index et un critere sont proposes pour quantifier l'asymetrie d'un materiau. Cette hypothese est souvent source d'imprecision des methodes de caracterisation inverses et indirectes en tube d'impedance. Le critere d'asymetrie propose permet ainsi de s'assurer de l'applicabilite et de la precision de ces methodes pour un materiau donne. Le troisieme probleme vise a mieux comprendre le probleme de transmission sonore en tube d'impedance en presentant pour la premiere fois un developpement exact du probleme par decomposition d'ondes. Ce developpement permet d'etablir clairement les limites des nombreuses methodes existantes basees sur des tubes de transmission a 2, 3 ou 4 microphones. La meilleure comprehension de ce probleme de transmission est importante puisque c'est par ce type de mesures que des methodes permettent d'extraire successivement la matrice de transfert d'un materiau poreux et ses proprietes dynamiques intrinseques comme son impedance caracteristique et son nombre d'onde complexe. Enfin, le quatrieme probleme porte sur le developpement d'une nouvelle methode de transmission exacte a 3 microphones applicable a des materiaux ou systemes symetriques ou non. Dans le cas symetrique, on montre que cette approche permet une nette amelioration de la caracterisation des proprietes dynamiques intrinseques d'un materiau. Mots cles. materiaux poreux, tube d'impedance, transmission sonore, absorption sonore, impedance acoustique, symetrie, porosite, matrice de transfert.

Provenance of the oil in par-fried French fries after finish frying.

PubMed

Al-Khusaibi, Mohammed; Gordon, Michael H; Lovegrove, Julie A; Niranjan, Keshavan

2012-01-01

Frozen par-fried French fries are finish-fried either by using the same type of oil used for par frying, or a different type. The nutritive quality of the final oil contained in the product depends on the relative amounts and the fatty acid (FA) composition of the oils used for par frying and finish frying. With the aim of understanding the provenance of the oil in the final product, par-fried French fries-either purchased ready or prepared in the laboratory-were finish fried in oils different from the ones used for par frying. The moisture content, oil content, and FA compositions of the par-fried and finish-fried products were experimentally determined, and the relative amounts of each of the oils present in the final product were calculated using the FAs as markers and undertaking a mass balance on each component FA. The results demonstrate that 89% to 93% of the total oil in the final product originates from the finish-frying step. The study also shows that a significant proportion of the oil absorbed during par frying is expelled from the product during finish frying. Further, the expulsion of par-frying oil was found to occur in the early stages of the finish-frying step. Experiments involving different combinations of par-frying and finish-frying oils showed that the relative proportions of the 2 oils did not depend on the individual fatty acid profiles. This study concludes that any positive health benefits of using an oil having a favorable FA profile for par frying, can potentially be lost, if the oil used for finish frying has a less favorable composition. This paper estimates the relative amounts of oil in French fries that have been fried in 2 stages-a par-frying step and a finish-frying step-which is commonly practiced in food service establishments as well as homes. The 2 key conclusions are: (1) nearly 90% of the oil content of the final product is the one used for finish frying; that is, a processor may use very good oil for par frying but if the oil used for finish frying is inferior, its effect will dominate. (2) The paper also shows that a significant proportion of the oil used by the processor gets expelled during finish frying. © 2011 Institute of Food Technologists®

Effect of Inhalation of Aromatherapy Oil on Patients with Perennial Allergic Rhinitis: A Randomized Controlled Trial.

PubMed

Choi, Seo Yeon; Park, Kyungsook

2016-01-01

This study aimed to investigate the effects of aromatherapy oil inhalation on symptoms, quality of life, sleep quality, and fatigue level among adults with perennial allergic rhinitis (PAR). Fifty-four men and women aged between 20 and 60 were randomized to inhale aromatherapy oil containing essential oil from sandalwood, geranium, and Ravensara or almond oil (the placebo) for 5 minutes twice daily for 7 days. PAR symptoms determined by Total Nasal Symptom Score (TNSS), the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), sleep quality by Verran Synder-Halpern (VSH) scale, and fatigue level by Chalder Fatigue Scale (CFS) were assessed before and after intervention period. Compared with the placebo, the experimental group showed significant improvement in TNSS, especially in nasal obstruction. The aromatherapy group also showed significantly higher improvements in total score of RQLQ and CFS. These findings indicate that inhalation of certain aromatherapy oil helps relieve PAR symptoms, improve rhinitis-specific quality of life, and reduce fatigue in patients with PAR. In conclusion, inhalation of aromatherapy essential oil may have potential as an effective intervention to alleviate PAR.

Optical heterogeneous bioassay for the detection of the inflammatory biomarker suPAR

NASA Astrophysics Data System (ADS)

Tombelli, S.; Trono, C.; Adinolfi, B.; Chiavaioli, F.; Giannetti, A.; Eugen-Olsen, J.; Bernini, R.; Grimaldi, I. A.; Persichetti, G.; Testa, G.; Baldini, F.

2015-03-01

Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory protein present in blood and a marker of disease presence, severity and prognosis. A heterogeneous sandwich assay is proposed for quantifying suPAR by employing a capture antibody from rat and a biotinylated detection antibody from mouse. Optical detection was achieved by a successive exposure of the biotinylated sandwich to streptavidin labelled with ATTO647N. The heterogeneous assay was implemented on a multichannel polymethylmetacrylate (PMMA) optical biochip, potentially capable of the simultaneous detection of more than one analyte. Capture antibody was immobilized on the PMMA surface of the microfluidic channel and the assay was performed with the following protocol: i) surface blocking with BSA, ii) incubation with suPAR or PBS, iii) incubation with biotinylated suPAR detection Ab and iv) incubation with streptavidin-ATTO647N. Promising preliminary results were obtained with this protocol. Moreover, an improved optical setup is proposed which avoids the mechanical scanning of the chip and consequently the in-series fluorescence excitation and read out, allowing the simultaneous measurement of the fluorescence on all the channels of the microfluidic chip.

Effect of Inhalation of Aromatherapy Oil on Patients with Perennial Allergic Rhinitis: A Randomized Controlled Trial

PubMed Central

Choi, Seo Yeon

2016-01-01

This study aimed to investigate the effects of aromatherapy oil inhalation on symptoms, quality of life, sleep quality, and fatigue level among adults with perennial allergic rhinitis (PAR). Fifty-four men and women aged between 20 and 60 were randomized to inhale aromatherapy oil containing essential oil from sandalwood, geranium, and Ravensara or almond oil (the placebo) for 5 minutes twice daily for 7 days. PAR symptoms determined by Total Nasal Symptom Score (TNSS), the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), sleep quality by Verran Synder-Halpern (VSH) scale, and fatigue level by Chalder Fatigue Scale (CFS) were assessed before and after intervention period. Compared with the placebo, the experimental group showed significant improvement in TNSS, especially in nasal obstruction. The aromatherapy group also showed significantly higher improvements in total score of RQLQ and CFS. These findings indicate that inhalation of certain aromatherapy oil helps relieve PAR symptoms, improve rhinitis-specific quality of life, and reduce fatigue in patients with PAR. In conclusion, inhalation of aromatherapy essential oil may have potential as an effective intervention to alleviate PAR. PMID:27034695

L'effet des deformations plastiques severes sur les proprietes d'hydruration du magnesium

NASA Astrophysics Data System (ADS)

Lang, Julien

Le travail de recherche effectue durant mon projet de maitrise en physique a l'Universite du Quebec a Trois-Rivieres dans les laboratoires de l'Institut de Recherche sur l'Hydrogene etait de comparer l'effet du laminage a froid de la poudre de MgH2 avec celui du broyage mecanique. Nous avons etudie cette nouvelle technique en utilisant un laminoir vertical concu specialement pour laminer de la poudre. Nous avons lamine la poudre de MgH2 5, 25, 50 et 100 fois. La comparaison de la morphologie de la poudre de MgH 2 telle que recu du manufacturier et broye mecaniquement pendant 30 minutes avec celle de la poudre laminee ete faite a l'aide d'un microscope electronique a balayage. Nous avons par la suite mesure les proprietes de sorption d'hydrogene grace un appareil PCT de type Sievert. Nous avons aussi determine la structure cristalline par diffraction de rayons X. A partir de ces resultats, nous avons constate que le nombre optimal de laminages est de cinq et a les caracteristiques d'absorption/desorption d'hydrogene similaires a un broyage mecanique de 30 minutes. Nous avons aussi utilise les courbes de cinetiques d'absorption et de desorption d'hydrogene pour calculer l'etape limitative dans les reactions de sorption des echantillons lamines. Comme cinq laminages se font en environ 10 secondes, on voit que le laminage a froid est une technique plus interessante industriellement que le broyage mecanique a cause de l'important gain en temps et en energie.

Participatory action research: considerations for ethical review.

PubMed

Khanlou, N; Peter, E

2005-05-01

This paper addresses the distinctive nature of participatory action research (PAR) in relation to ethical review requirements. As a framework for conducting research and reducing health disparities, PAR is gaining increased attention in community and public health research. As a result, PAR researchers and members of Research Ethics Boards could benefit from an increased understanding of the array of ethical concerns that can arise. We discuss these concerns in light of commonly held ethical requirements for clinical research (social or scientific value, scientific validity, fair subject/participant selection, favourable risk-benefit ratio, independent review, informed consent, and respect for potential and enrolled participants) and refer to guidelines specifically developed for participatory research in health promotion. We draw from our community-based experiences in mental health promotion research with immigrant and culturally diverse youth to illustrate the ethical advantages and challenges of applying a PAR approach. We conclude with process suggestions for Research Ethics Boards.

Protease activated receptor-2 (PAR2): possible target of phytochemicals.

PubMed

Kakarala, Kavita Kumari; Jamil, Kaiser

2015-09-01

The use of phytochemicals either singly or in combination with other anticancer drugs comes with an advantage of less toxicity and minimal side effects. Signaling pathways play central role in cell cycle, cell growth, metabolism, etc. Thus, the identification of phytochemicals with promising antagonistic effect on the receptor/s playing key role in single transduction may have better therapeutic application. With this background, phytochemicals were screened against protease-activated receptor 2 (PAR2). PAR2 belongs to the superfamily of GPCRs and is an important target for breast cancer. Using in silico methods, this study was able to identify the phytochemicals with promising binding affinity suggesting their therapeutic potential in the treatment of breast cancer. The findings from this study acquires importance as the information on the possible agonists and antagonists of PAR2 is limited due its unique mechanism of activation.

Monsoon variability of ultraviolet radiation (UVR) attenuation and bio-optical factors in the Asian tropical coral-reef waters

NASA Astrophysics Data System (ADS)

Mizubayashi, Keiko; Kuwahara, Victor S.; Segaran, Thirukanthan C.; Zaleha, Kassim; Effendy, A. W. M.; Kushairi, M. R. M.; Toda, Tatsuki

2013-07-01

The East coast of Peninsular Malaysia is strongly influenced by the North-East (NE) monsoon, and may significantly influence the optical environment of coral-reef ecosystems. However, our knowledge of temporal variability, including episodic events, of environmental factors in Asian tropical regions is still limited. The objectives of this study were to (1) observe temporal variability in ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) attenuation and (2) determine the bio-optical factors regulating the optical environment in shallow coral-reef waters. Downwelling UVR and PAR irradiance and in situ bio-optical factors were measured monthly near Bidong Island on the East coast of Peninsular Malaysia from June 2010 to June 2011. The NE monsoon was recognized between November 2010 and January 2011. The highest diffuse attenuation coefficient at 305 nm was 2.05 ± 0.03 m-1 in a coral-reef area on December 2010. The most significant bio-optical factor at 305, 380, 440 nm during the NE monsoon season was CDOM (89 ± 8% at 305 nm, 84 ± 9% at 380 nm and 49 ± 17% at 440 nm). All UVR attenuation coefficients showed significant correlations with the CDOM absorption coefficients (aCDOM). CDOM with relatively low S275-295 during the NE monsoon season (0.0177 ± 0.0020 nm-1) suggests terrestrial sources, which is also supported by the correlation between salinity and aCDOM(305). A significant correlation between S275-295 and the carbon specific absorbance coefficient (a*(305)) suggest the potential to measure DOC optically in these waters. The high CDOM during the NE monsoon season may have an important role to reduce harmful UVR exposure reaching benthic communities.

Tight junctions of the proximal tubule and their channel proteins.

PubMed

Fromm, Michael; Piontek, Jörg; Rosenthal, Rita; Günzel, Dorothee; Krug, Susanne M

2017-08-01

The renal proximal tubule achieves the majority of renal water and solute reabsorption with the help of paracellular channels which lead through the tight junction. The proteins forming such channels in the proximal tubule are claudin-2, claudin-10a, and possibly claudin-17. Claudin-2 forms paracellular channels selective for small cations like Na + and K + . Independently of each other, claudin-10a and claudin-17 form anion-selective channels. The claudins form the paracellular "pore pathway" and are integrated, together with purely sealing claudins and other tight junction proteins, in the belt of tight junction strands surrounding the tubular epithelial cells. In most species, the proximal tubular tight junction consists of only 1-2 (pars convoluta) to 3-5 (pars recta) horizontal strands. Even so, they seal the tubule very effectively against leak passage of nutrients and larger molecules. Remarkably, claudin-2 channels are also permeable to water so that 20-25% of proximal water absorption may occur paracellularly. Although the exact structure of the claudin-2 channel is still unknown, it is clear that Na + and water share the same pore. Already solved claudin crystal structures reveal a characteristic β-sheet, comprising β-strands from both extracellular loops, which is anchored to a left-handed four-transmembrane helix bundle. This allowed homology modeling of channel-forming claudins present in the proximal tubule. The surface of cation- and anion-selective claudins differ in electrostatic potentials in the area of the proposed ion channel, resulting in the opposite charge selectivity of these claudins. Presently, while models of the molecular structure of the claudin-based oligomeric channels have been proposed, its full understanding has only started.

Frequent topoisomerase IV mutations associated with fluoroquinolone resistance in Ureaplasma species.

PubMed

Song, Jingjuan; Qiao, Yingli; Kong, Yingying; Ruan, Zhi; Huang, Jun; Song, Tiejun; Zhang, Jun; Xie, Xinyou

2015-11-01

This study aimed to investigate the role of quinolone resistance-determining regions (QRDRs) of DNA gyrase (encoded by gyrA and gyrB) and topoisomerase IV (encoded by parC and parE) associated with fluoroquinolone resistance. A total of 114 Ureaplasma spp. strains, isolated from clinical female patients with symptomatic infection, were tested for species distribution and susceptibility to four fluoroquinolones. Moreover, we analysed the QRDRs and compared these with 14 ATCC reference strains of Ureaplasma spp. serovars to identify mutations that caused antimicrobial resistance. Our study indicated that moxifloxacin was the most effective fluoroquinolone against Ureaplasma spp. (MIC range: 0.125-32 μg ml⁻¹). However, extremely high MICs were estimated for ciprofloxacin (MIC range: 1-256 μg ml⁻¹) and ofloxacin (MIC range: 0.5-128 μg ml⁻¹), followed by levofloxacin (MIC range: 0.5-64 μg ml⁻¹). Seven amino acid substitutions were discovered in GyrB, ParC and ParE, but not in GyrA. Ser-83 → Leu/Trp (C248T/G) in ParC and Arg-448 → Lys (G1343A) in ParE, which were potentially responsible for fluoroquinolone resistance, were observed in 89 (77.2 %) and three (2.6 %) strains, respectively. Pro-462 → Ser (C1384T), Asn-481 → Ser (A1442G) and Ala-493 → Val (C1478T) in GyrB and Met-105 → Ile (G315T) in ParC seemed to be neutral polymorphisms, and were observed and occurred along with the amino acid change of Ser-83 → Leu (C248T) in ParC. Interestingly, two novel mutations of ParC and ParE were independently found in four strains. These observations suggest that amino acid mutation in topoisomerase IV appears to be the leading cause of fluoroquinolone resistance, especially the mutation of Ser-83 → Leu (C248T) in ParC. Moxifloxacin had the best activity against strains with Ser-83 → Leu mutation.

An electrochemical sensor prepared by sonochemical one-pot synthesis of multi-walled carbon nanotube-supported cobalt nanoparticles for the simultaneous determination of paracetamol and dopamine.

PubMed

Kutluay, Aysegul; Aslanoglu, Mehmet

2014-08-11

Multi-walled carbon nanotubes (MWCNTs) functionalized by cobalt nanoparticles were obtained using a single step chemical deposition method in an ultrasonic bath. The composite material was characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The electroactivity of the cobalt-functionalized MWCNTs was assessed in respect to the electrooxidation of paracetamol (PAR) and dopamine (DA). It was found that the carbon nanotube supported cobalt nanoparticles have significantly higher catalytic properties. The proposed electrode has been applied for the simultaneous determination of PAR and DA. The modified electrode could resolve the overlapped voltammetric waves of PAR and DA into two well-defined voltammetric peaks with peak to peak separation of about 203 mV. On the other hand, the presence of potential drug interfering compounds AA and UA did not affect the voltammetric responses of PAR and DA. The current of oxidation peaks showed a linear dependent on the concentrations of PAR and DA in the range of 5.2×10(-9)-4.5×10(-7) M (R(2)=0.9987) and 5.0×10(-8)-3.0×10(-6) M (R(2)=0.9999), respectively. The detection limits of 1.0×10(-9) M and 1.5×10(-8) M were obtained for PAR and DA, respectively. The proposed electrode showed good stability (peak current change: 4.9% with and RSD of 2.6% for PAR; 5.5% with and RSD of 3.0% for DA over 3 weeks), reproducibility (RSD 2.3% for PAR and RSD 1.5% for DA), repeatability (RSD 2.25% for PAR and RSD 2.50% for DA) and high recovery (99.7% with an RSD of 1.3% for PAR; 100.8% with an RSD of 1.8% for DA). The proposed method was successfully applied to the determination of PAR and DA in pharmaceuticals. Copyright © 2014. Published by Elsevier B.V.

Assessment of Mercury Concentration in Turtles (Podocnemis unifilis) in the Xingu River Basin, Brazil.

PubMed

Pignati, Marina Teófilo; Pezzuti, Juarez Carlos Brito; Souza, Larissa Costa de; Lima, Marcelo de Oliveira; Pignati, Wanderlei Antonio; Mendes, Rosivaldo de Alcântara

2018-06-06

Many studies on mercury contamination in aquatic biota deal with the effect of consuming metal-contaminated organisms on human health. In this study, we examined the factors that cause mercury contamination in Podocnemis unifilis in the Xingu River Basin of Mato Grosso and Pará States, Brazil. We quantified by atomic absorption spectroscopy with cold vapor the total mercury (THg) content in the liver and muscle samples of 50 Podocnemis unifilis specimens collected from the basin. The liver and muscle samples contained 134.20 ± 119.30 ng g −1 THg and 24.86 ± 26.36 ng g −1 THg, respectively. Each chelonian or meal has, on average, 5.34× more Hg than the highest level established as acceptable. From the results it can be inferred that, given the weekly consumption of chelonians, the riverine and indigenous communities in the Xingu River Basin are at risk of chronic consumption of Hg in amounts beyond the acceptable limit. The potential high risk to the health of this population is evident; however, the risk classification needs to be further studied.

Endophthalmitis following 27-Gauge Pars Plana Vitrectomy for Vitreous Floaters.

PubMed

Lin, Zhong; Wu, Rong Han; Moonasar, Nived

2016-01-01

To report a case of Staphylococcus epidermidis endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. The clinical course and imaging findings, including fundus optomap, and spectral domain optical coherence tomography of a 24-year-old male patient were documented. The patient, with a preoperative best-corrected visual acuity (BCVA) of 1.0, developed endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. After a series of treatments, including emergent vitreous tap and silicone oil injection, antibiotic treatment, and silicone oil removal, the patient regained a BCVA of 0.6. Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters.

PAR-2 activation enhances weak acid-induced ATP release through TRPV1 and ASIC sensitization in human esophageal epithelial cells.

PubMed

Wu, Liping; Oshima, Tadayuki; Shan, Jing; Sei, Hiroo; Tomita, Toshihiko; Ohda, Yoshio; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

2015-10-15

Esophageal visceral hypersensitivity has been proposed to be the pathogenesis of heartburn sensation in nonerosive reflux disease. Protease-activated receptor-2 (PAR-2) is expressed in human esophageal epithelial cells and is believed to play a role in inflammation and sensation. PAR-2 activation may modulate these responses through adenosine triphosphate (ATP) release, which is involved in transduction of sensation and pain. The transient receptor potential vanilloid receptor 1 (TRPV1) and acid-sensing ion channels (ASICs) are both acid-sensitive nociceptors. However, the interaction among these molecules and the mechanisms of heartburn sensation are still not clear. We therefore examined whether ATP release in human esophageal epithelial cells in response to acid is modulated by TRPV1 and ASICs and whether PAR-2 activation influences the sensitivity of TRPV1 and ASICs. Weak acid (pH 5) stimulated the release of ATP from primary human esophageal epithelial cells (HEECs). This effect was significantly reduced after pretreatment with 5-iodoresiniferatoxin (IRTX), a TRPV1-specific antagonist, or with amiloride, a nonselective ASIC blocker. TRPV1 and ASIC3 small interfering RNA (siRNA) transfection also decreased weak acid-induced ATP release. Pretreatment of HEECs with trypsin, tryptase, or a PAR-2 agonist enhanced weak acid-induced ATP release. Trypsin treatment led to the phosphorylation of TRPV1. Acid-induced ATP release enhancement by trypsin was partially blocked by IRTX, amiloride, or a PAR-2 antagonist. Conversely, acid-induced ATP release was augmented by PAR-2 activation through TRPV1 and ASICs. These findings suggested that the pathophysiology of heartburn sensation or esophageal hypersensitivity may be associated with the activation of PAR-2, TRPV1, and ASICs. Copyright © 2015 the American Physiological Society.

[Effect of ERK/AP-1 signaling pathway on proliferation of hepatoma cells induced by PAR-2 agonists].

PubMed

Zheng, Yan-min; Xie, Li-qun; Li, Xuan; Zhao, Jun-yan; Chen, Xiao-yi; Chen, Li; Zhou, Jing; Li, Fei

2009-12-01

To investigate the expression of protease activated receptor-2 (PAR-2) in human HepG2 hepatoma cells and elucidate the effects of trypsin and PAR-2 agonist peptide SLIGKV-NH(2) upon the proliferation of hepatoma cells and its intracellular signaling mechanism. PAR-2 protein and mRNA expression were detected by immunofluorescence and RT-PCR. The cells were treated with SLIGKV-NH(2), trypsin, reverse PAR-2 agonist peptide VKGILS-NH(2) or PD98059. The changes of cell cycle distribution were evaluated by flow cytometry. The proliferative potential of HepG2 cells was estimated by MTT. The changes of PAR-2, c-fos and PCNA mRNA expression were detected by RT-PCR. The changes of c-fos and PCNA protein expression were detected by Western blotting. PAR-2 protein and mRNA were expressed in HepG2 cells. PAR-2 mRNA expression (PAR-2/beta-actin) were 0.70 +/- 0.04 and 0.99 +/- 0.05 respectively in cells treated with trypsin and SLIGKV-NH(2). They were both significantly higher than that in the control group (0.35 +/- 0.05, F = 135.534, P < 0.01). Percent G(0)/G(1) phase of HepG2 cells treated with trypsin or SLIGKV-NH(2) were significantly lower than those in the control group [(56.11 +/- 0.85)%, (57.85 +/- 0.46)% vs (79.12 +/- 0.67)%, both P < 0.01] Percent S phase, G(2)/M phase and proliferation index (PI) of HepG2 cells treated with trypsin or SLIGKV-NH(2) were significantly elevated (P < 0.01). The proliferation-enhancing effects and the up-regulation of mRNA and protein of c-fos and PCNA induced by trypsin or SLIGKV-NH(2) were significantly blocked by pretreatment with PD98059 (P < 0.01). There was no statistical significance in proliferation of HepG2 cells between the reverse PAR-2 agonist peptide VKGILS-NH(2) and control group (P > 0.05). PAR-2 is expressed in HepG2 hepatoma cells. PAR-2 activation induced by trypsin or SLIGKV-NH(2) promotes the proliferation of HepG2 cells partially via the ERK/AP-1 pathway.

Remote sensing of the Canadian Arctic: Modelling biophysical variables

NASA Astrophysics Data System (ADS)

Liu, Nanfeng

It is anticipated that Arctic vegetation will respond in a variety of ways to altered temperature and precipitation patterns expected with climate change, including changes in phenology, productivity, biomass, cover and net ecosystem exchange. Remote sensing provides data and data processing methodologies for monitoring and assessing Arctic vegetation over large areas. The goal of this research was to explore the potential of hyperspectral and high spatial resolution multispectral remote sensing data for modelling two important Arctic biophysical variables: Percent Vegetation Cover (PVC) and the fraction of Absorbed Photosynthetically Active Radiation (fAPAR). A series of field experiments were conducted to collect PVC and fAPAR at three Canadian Arctic sites: (1) Sabine Peninsula, Melville Island, NU; (2) Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, NU; and (3) Apex River Watershed (ARW), Baffin Island, NU. Linear relationships between biophysical variables and Vegetation Indices (VIs) were examined at different spatial scales using field spectra (for the Sabine Peninsula site) and high spatial resolution satellite data (for the CBAWO and ARW sites). At the Sabine Peninsula site, hyperspectral VIs exhibited a better performance for modelling PVC than multispectral VIs due to their capacity for sampling fine spectral features. The optimal hyperspectral bands were located at important spectral features observed in Arctic vegetation spectra, including leaf pigment absorption in the red wavelengths and at the red-edge, leaf water absorption in the near infrared, and leaf cellulose and lignin absorption in the shortwave infrared. At the CBAWO and ARW sites, field PVC and fAPAR exhibited strong correlations (R2 > 0.70) with the NDVI (Normalized Difference Vegetation Index) derived from high-resolution WorldView-2 data. Similarly, high spatial resolution satellite-derived fAPAR was correlated to MODIS fAPAR (R2 = 0.68), with a systematic overestimation of 0.08, which was attributed to PAR absorption by soil that could not be excluded from the fAPAR calculation. This research clearly demonstrates that high spectral and spatial resolution remote sensing VIs can be used to successfully model Arctic biophysical variables. The methods and results presented in this research provided a guide for future studies aiming to model other Arctic biophysical variables through remote sensing data.

Extended generation profile - E.B.I.C model application in the case of a PN junction

NASA Astrophysics Data System (ADS)

Guermazi, S.; Toureille, A.; Grill, C.; El Jani, B.

2000-01-01

We have developed a model for the calculation of the induced current due to an electron beam with an extended generation profile. Added to the absorbed and diffuse electrons in the depth distribution, the generation profile takes into account the lateral diffusion. The analytical expression of the electron beam induced current (EBIC) is obtained by solving the continuity equation in permanent regime by the Green function method. The induced current profile, obtained in the case of a ternary component (Ga{0.7}Al{0.3}As:N^+/Ga{0.7}Al{0.3}As:P) sulfur doped and prepared by organometallic compounds phase vapor epitaxy method, is compared to the theoretical profiles whose analytical expressions are given by Van Roosbroeck and Bresse. The experimental current profile, measured by S.E.M provided us to calculate the diffusion length of the minority carriers: L_p=1 μm in the N region and L_n=1.80 μm in the P region of the ternaire component. The theoretical curve obtained from the proposed model is in good agreement with the experimental one for a surface recombination velocity of 10^6 cm s^{-1}. Our results are found to be consistent compared to those obtained by other experimental techniques using the same samples. Nous avons développé un modèle de calcul du courant induit par un faisceau d'électrons avec un profil de génération élargi. Le profil de génération prend en compte la répartition spatiale de la diffusion et de l'absorption des électrons. L'expression analytique du courant induit (E.B.I.C) est déterminée par résolution de l'équation de continuité en régime permanent par la méthode des fonctions de Green. Le profil de courant induit obtenu dans le cas d'une jonction PN (Ga{0,7}Al{0,3}As:N^+/Ga{0,7}Al{0,3}As:P) dopée par le soufre et préparée par épitaxie à phase vapeur organo-métallique, est comparé au profil de courant théorique dont l'expression analytique est explicitée par Van Roosbroeck et Bresse. Le profil expérimental de courant E.B.I.C, mesuré par un microscope électronique à balayage, nous a permis de déterminer la longueur de diffusion des porteurs minoritaires L_p=1 μm dans la région N du composant ternaire et L_n=1,8 μm dans la région P de ce composant. La courbe théorique, tracée à partir du modèle proposé, est en bon accord avec la courbe expérimentale pour une vitesse de recombinaison à la surface de 10^6 cm s^{-1}. Ces résultats sont conformes avec ceux obtenus par d'autres techniques expérimentales sur les mêmes échantillons.

18-year variability of ultraviolet radiation penetration in the mid-latitude coastal waters of the western boundary Pacific

NASA Astrophysics Data System (ADS)

Kuwahara, Victor S.; Nozaki, Sena; Nakano, Junji; Toda, Tatsuki; Kikuchi, Tomohiko; Taguchi, Satoru

2015-07-01

The 18-year time-series shows in situ ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) diffuse attenuation coefficient Kd(λ) have recurrent seasonal variability of high/low attenuation during summer/winter months, respectively, dependent on variability in water column stratification and concentrations of bio-optical properties. The mid-latitude coastal survey station displayed significant seasonality of the mixed layer depth (MLD) between 12 and 82 m which modified the distribution of chlorophyll a (4.6-24.9 mg m-2) and absorption of colored dissolved organic matter [aCDOM(320 nm) 0.043-1.34 m-1]. The median Kd(320 nm) displayed significant seasonality at 0.19-0.74 m-1 (C.V. = 44.1%) and seasonal variability within the euphotic layer [Z10%(320 nm) = 7-20%]. High attenuation of UVR with relatively moderate attenuation of PAR was consistently observed during the summer months when increased concentrations of terrestrially derived CDOM coupled with a shallow MLD were present. The winter season showed the opposite of low UVR and PAR attenuation due to a relatively deeper MLD coupled with low concentrations of bio-optical properties. Although the long term Kd(λ) did not vary significantly during the time-series, analysis of the interannual variability suggests there are positive and negative phases following the Pacific Decadal Oscillation (PDO) vis-a-vis variability in bio-optical properties (p < 0.001).

Character of intermolecular interaction in pyridine-argon complex: Ab initio potential energy surface, internal dynamics, and interrelations between SAPT energy components.

PubMed

Makarewicz, Jan; Shirkov, Leonid

2016-05-28

The pyridine-Ar (PAr) van der Waals (vdW) complex is studied using a high level ab initio method. Its structure, binding energy, and intermolecular vibrational states are determined from the analytical potential energy surface constructed from interaction energy (IE) values computed at the coupled cluster level of theory with single, double, and perturbatively included triple excitations with the augmented correlation consistent polarized valence double-ζ (aug-cc-pVDZ) basis set complemented by midbond functions. The structure of the complex at its global minimum with Ar at a distance of 3.509 Å from the pyridine plane and shifted by 0.218 Å from the center of mass towards nitrogen agrees well with the corresponding equilibrium structure derived previously from the rotational spectrum of PAr. The PAr binding energy De of 392 cm(-1) is close to that of 387 cm(-1) calculated earlier at the same ab initio level for the prototypical benzene-Ar (BAr) complex. However, under an extension of the basis set, De for PAr becomes slightly lower than De for BAr. The ab initio vdW vibrational energy levels allow us to estimate the reliability of the methods for the determination of the vdW fundamentals from the rotational spectra. To disclose the character of the intermolecular interaction in PAr, the symmetry-adapted perturbation theory (SAPT) is employed for the analysis of different physical contributions to IE. It is found that SAPT components of IE can be approximately expressed in the binding region by only two of them: the exchange repulsion and dispersion energy. The total induction effect is negligible. The interrelations between various SAPT components found for PAr are fulfilled for a few other complexes involving aromatic molecules and Ar or Ne, which indicates that they are valid for all rare gas (Rg) atoms and aromatics.

A comparative analysis of novel cardiovascular biomarkers in patients with chronic heart failure.

PubMed

Lichtenauer, Michael; Jirak, Peter; Wernly, Bernhard; Paar, Vera; Rohm, Ilonka; Jung, Christian; Schernthaner, Christiana; Kraus, Johannes; Motloch, Lukas J; Yilmaz, Atilla; Hoppe, Uta C; Christian Schulze, P; Kretzschmar, Daniel; Pistulli, Rudin

2017-10-01

Heart failure (HF) with reduced ejection fraction remains a major therapeutic challenge. The aim of this study was to investigate the role of novel cardiovascular biomarkers, i.e. soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR) and heart-type fatty acid binding protein (H-FABP) in patients with ischaemic (ICM) or dilative cardiomyopathy (DCM). A total of 200 patients were enrolled in this study: 65 were diagnosed with DCM and 59 patients suffering from ICM were included. 76 patients without coronary artery disease or signs of heart failure were included as controls. Plasma samples of all patients were analyzed by use of ELISA. Levels of sST2, suPAR and H-FABP were significantly higher in ICM and DCM patients compared to the control group (p<0.0001). However, there were no significant differences between ICM and DCM in biomarker levels. Ejection fraction correlated inversely with cardiac biomarkers (sST2 p<0.0001, GDF-15 p=0.0394, suPAR p=0.0029, H-FABP p<0.0001). Similarly, CRP levels also showed a positive correlation with cardiac biomarkers. Renal insufficiency (p<0.0001) and diabetes (sST2 p=0.0021, GDF-15 p=0.0055, suPAR p=0.0339, H-FABP p=0.0010) were significantly associated with a rise in cardiac biomarkers. Novel cardiovascular biomarkers such as ST2, GDF-15, uPAR and H-FABP could offer a great potential for more precise diagnostic in ICM and DCM patients. H-FABP was the most promising marker in our study, followed by sST2, uPAR and GDF-15. Additional prospective studies will be necessary to further evaluate the potential clinical benefits in routine treatment of HF. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Dual targeting DNA gyrase B (GyrB) and topoisomerse IV (ParE) inhibitors: A review.

PubMed

Azam, Mohammed Afzal; Thathan, Janarthanan; Jubie, Selvaraj

2015-10-01

GyrB and ParE are type IIA topoisomerases and found in most bacteria. Its function is vital for DNA replication, repair and decatenation. The highly conserved ATP-binding subunits of DNA GyrB and ParE are structurally related and have been recognized as prime candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, no natural product or small molecule inhibitors targeting ATPase catalytic domain of both GyrB and ParE enzymes have succeeded in the clinic. Moreover, no inhibitors of these enzymes with broad-spectrum antibacterial activity against Gram-negative pathogens have been reported. Availability of high resolution crystal structures of GyrB and ParE made it possible for the design of many different classes of inhibitors with dual mechanism of action. Among them benzimidazoles, benzothiazoles, thiazolopyridines, imidiazopyridazoles, pyridines, indazoles, pyrazoles, imidazopyridines, triazolopyridines, pyrrolopyrimidines, pyrimidoindoles as well as related structures are disclosed in literatures. Unfortunately most of these inhibitors are found to be active against Gram-positive pathogens. In the present review we discuss about studies on novel dual targeting ATPase inhibitors. Copyright © 2015 Elsevier Inc. All rights reserved.

Proteinase-Activated Receptor 2 May Drive Cancer Progression by Facilitating TGF-β Signaling.

PubMed

Ungefroren, Hendrik; Witte, David; Rauch, Bernhard H; Settmacher, Utz; Lehnert, Hendrik; Gieseler, Frank; Kaufmann, Roland

2017-11-22

The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer, it usually acts as a driver of cancer progression in various tumor types by promoting invasion and metastasis in response to activation by serine proteinases. Recently, we discovered another mode through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-β (TGF-β) signaling to promote TGF-β1-induced cell migration/invasion and invasion-associated gene expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is known about the cellular TGF-β responses and signaling pathways affected by PAR2 expression, the signaling activities of PAR2 required for promoting TGF-β signaling, and the potential molecular mechanism(s) that underlie(s) the TGF-β signaling-promoting effect. Since PAR2 is activated through various serine proteinases and biased agonists, it may couple TGF-β signaling to a diverse range of other physiological processes that may or may not predispose cells to cancer development such as local inflammation, systemic coagulation and pathogen infection.

Proteinase-Activated Receptor 2 May Drive Cancer Progression by Facilitating TGF-β Signaling

PubMed Central

Ungefroren, Hendrik; Witte, David; Settmacher, Utz; Lehnert, Hendrik; Kaufmann, Roland

2017-01-01

The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer, it usually acts as a driver of cancer progression in various tumor types by promoting invasion and metastasis in response to activation by serine proteinases. Recently, we discovered another mode through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-β (TGF-β) signaling to promote TGF-β1-induced cell migration/invasion and invasion-associated gene expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is known about the cellular TGF-β responses and signaling pathways affected by PAR2 expression, the signaling activities of PAR2 required for promoting TGF-β signaling, and the potential molecular mechanism(s) that underlie(s) the TGF-β signaling–promoting effect. Since PAR2 is activated through various serine proteinases and biased agonists, it may couple TGF-β signaling to a diverse range of other physiological processes that may or may not predispose cells to cancer development such as local inflammation, systemic coagulation and pathogen infection. PMID:29165389

Vps26B-retromer negatively regulates plasma membrane resensitization of PAR-2.

PubMed

Bugarcic, Andrea; Vetter, Irina; Chalmers, Silke; Kinna, Genevieve; Collins, Brett M; Teasdale, Rohan D

2015-11-01

Retromer is a trimeric complex composed of Vps26, Vps29, and Vps35 and has been shown to be involved in trafficking and sorting of transmembrane proteins within the endosome. The Vps26 paralog, Vps26B, defines a distinct retromer complex (Vps26B-retromer) in vivo and in vitro. Although endosomally associated, Vps26B-retromer does not bind the established retromer transmembrane cargo protein, cation-independent mannose 6-phosphate receptor (CI-M6PR), indicating it has a distinct role to retromer containing the Vps26A paralog. In the present study we use the previously established Vps26B-expressing HEK293 cell model to address the role of Vps26B-retromer in trafficking of the protease activated G-protein coupled receptor PAR-2 to the plasma membrane. In these cells there is no apparent defect in the initial activation of the receptor, as evidenced by release of intracellular calcium, ERK1/2 signaling and endocytosis of activated receptor PAR-2 into degradative organelles. However, we observe a significant delay in plasma membrane repopulation of the protease activated G protein-coupled receptor PAR-2 following stimulation, resulting in a defect in PAR-2 activation after resensitization. Here we propose that PAR-2 plasma membrane repopulation is regulated by Vps26B-retromer, describing a potential novel role for this complex. © 2015 International Federation for Cell Biology.

"It was like reading a detective novel": Using PAR to work together for culture change.

PubMed

Fortune, Darla; McKeown, Janet; Dupuis, Sherry; de Witt, Lorna

2015-08-01

Participatory action research (PAR), with its focus on engagement and collaboration, is uniquely suited to enhancing culture change initiatives in dementia care. Yet, there is limited literature of its application to culture change approaches in care settings, and even less in dementia specific care contexts. To address these gaps in the literature, the purpose of this paper is to examine the complexities of a PAR project aimed at changing the culture of dementia care in two diverse dementia care settings, including a long term care (LTC) and community care setting. Drawing from data gathered throughout the PAR process, we unpack the challenges experienced by participants working together to guide culture change within their respective care settings. These challenges include: overextending selves through culture change participation; fluctuating group membership; feeling uncertainty, confusion and apprehension about the process; frustratingly slow process; and seeking diverse group representation in decision making. We also highlight the potential for appreciative inquiry (AI) to be integrated with PAR to guide a process whereby participants involved in culture change initiatives can develop strategies to mitigate challenges they experience. We view the challenges and strategies shared here as being constructive to would-be culture change agents and hope this paper will move others to consider the use of PAR when engaging in culture change initiatives. Copyright © 2015 Elsevier Inc. All rights reserved.

Increased production of BDNF in colonic epithelial cells induced by fecal supernatants from diarrheic IBS patients.

PubMed

Wang, Peng; Chen, Fei-Xue; Du, Chao; Li, Chang-Qing; Yu, Yan-Bo; Zuo, Xiu-Li; Li, Yan-Qing

2015-05-22

Colonic brain-derived neurotrophic factor (BDNF) plays an essential role in pathogenesis of abdominal pain in diarrhea-predominant irritable bowel syndrome (IBS-D), but regulation on its expression remains unclear. We investigated the role of fecal supernatants (FSN) from IBS-D patients on regulating BDNF expression in colonic epithelial cells of human and mice. Using human Caco-2 cells, we found that IBS-D FSN significantly increased BDNF mRNA and protein levels compared to control FSN, which were remarkably suppressed by the serine protease inhibitor. To further explore the potential mechanisms, we investigated the impact of protease-activated receptor-2 (PAR-2) on BDNF expression. We found a significant increase in PAR-2 expression in Caco-2 after IBS-D FSN stimulation. Knockdown of PAR-2 significantly inhibited IBS-D FSN-induced upregulation of BDNF. Moreover, we found that phosphorylation of p38 MAPK, not NF-κB p65, contributed to PAR-2-mediated BDNF overexpression. To confirm these results, we intracolonically infused IBS-D or control FSN in mice and found that IBS-D FSN significantly elevated colonic BDNF and visceral hypersensitivity in mice, which were both suppressed by the inhibitor of serine protease or antagonist of PAR-2. Together, our data indicate that activation of PAR-2 signaling by IBS-D FSN promotes expression of colonic BDNF, thereby contributing to IBS-like visceral hypersensitivity.

Supplementing cross-cover communication with the patient acuity rating.

PubMed

Phillips, Andrew W; Yuen, Trevor C; Retzer, Elizabeth; Woodruff, James; Arora, Vineet; Edelson, Dana P

2013-03-01

Patient hand-offs at physician shift changes have limited ability to convey the primary team's longitudinal insight. The Patient Acuity Rating (PAR) is a previously validated, 7-point scale that quantifies physician judgment of patient stability, where a higher score indicates a greater risk of clinical deterioration. Its impact on cross-covering physician understanding of patients is not known. To determine PAR contribution to sign-outs. Cross-sectional survey. Intern physicians at a university teaching hospital. Subjects were surveyed using randomly chosen, de-identified patient sign-outs, previously assigned PAR scores by their primary teams. For each sign-out, subjects assigned a PAR score, then responded to hypothetical cross-cover scenarios before and after being informed of the primary team's PAR. Changes in intern assessment of the scenario before and after being informed of the primary team's PAR were measured. In addition, responses between novice and experienced interns were compared. Between May and July 2008, 23 of 39 (59 %) experienced interns and 25 of 42 (60 %) novice interns responded to 480 patient scenarios from ten distinct sign-outs. The mean PAR score assigned by subjects was 4.2 ± 1.6 vs. 3.8 ± 1.8 by the primary teams (p < 0.001). After viewing the primary team's PAR score, interns changed their level of concern in 47.9 % of cases, their assessment of the importance of immediate bedside evaluation in 48.7 % of cases, and confidence in their assessment in 43.2 % of cases. For all three assessments, novice interns changed their responses more frequently than experienced interns (p = 0.03, 0.009, and <0.001, respectively). Overall interns reported the PAR score to be theoretically helpful in 70.8 % of the cases, but this was more pronounced in novice interns (81.2 % vs 59.6 %, p < 0.001). The PAR adds valuable information to sign-outs that could impact cross-cover decision-making and potentially benefit patients. However, correct training in its use may be required to avoid unintended consequences.

Endophthalmitis following 27-Gauge Pars Plana Vitrectomy for Vitreous Floaters

PubMed Central

Lin, Zhong; Wu, Rong Han; Moonasar, Nived

2016-01-01

Purpose To report a case of Staphylococcus epidermidis endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. Methods The clinical course and imaging findings, including fundus optomap, and spectral domain optical coherence tomography of a 24-year-old male patient were documented. Results The patient, with a preoperative best-corrected visual acuity (BCVA) of 1.0, developed endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. After a series of treatments, including emergent vitreous tap and silicone oil injection, antibiotic treatment, and silicone oil removal, the patient regained a BCVA of 0.6. Conclusion Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters. PMID:28101041

Protease-activated receptor 2-mediated protection of myocardial ischemia-reperfusion injury: role of transient receptor potential vanilloid receptors

PubMed Central

Zhong, Beihua

2009-01-01

Activation of the protease-activated receptor 2 (PAR2) or the transient receptor potential vanilloid type 1 (TRPV1) channels expressed in cardiac sensory afferents containing calcitonin gene-related peptide (CGRP) and/or substance P (SP) has been proposed to play a protective role in myocardial ischemia-reperfusion (I/R) injury. However, the interaction between PAR2 and TRPV1 is largely unknown. Using gene-targeted TRPV1-null mutant (TRPV1−/−) or wild-type (WT) mice, we test the hypothesis that TRPV1 contributes to PAR2-mediated cardiac protection via increasing the release of CGRP and SP. Immunofluorescence labeling showed that TRPV1 coexpressed with PAR2, PKC-ε, or PKAc in cardiomyocytes, cardiac blood vessels, and perivascular nerves in WT but not TRPV1−/− hearts. WT or TRPV1−/− hearts were Langendorff perfused with the selective PAR2 agonist, SLIGRL, in the presence or absence of various antagonists, followed by 35 min of global ischemia and 40 min of reperfusion (I/R). The recovery rate of coronary flow, the maximum rate of left ventricular pressure development, left ventricular end-diastolic pressure, and left ventricular developed pressure were evaluated after I/R. SLIGRL improved the recovery of hemodynamic parameters, decreased lactate dehydrogenase release, and reduced the infarct size in both WT and TRPV1−/− hearts (P < 0.05). The protection of SLIGRL was significantly surpassed for WT compared with TRPV1−/− hearts (P < 0.05). CGRP8–37, a selective CGRP receptor antagonist, RP67580, a selective neurokinin-1 receptor antagonist, PKC-ε V1–2, a selective PKC-ε inhibitor, or H-89, a selective PKA inhibitor, abolished SLIGRL protection by inhibiting the recovery of the rate of coronary flow, maximum rate of left ventricular pressure development, and left ventricular developed pressure, and increasing left ventricular end-diastolic pressure in WT but not TRPV1−/− hearts. Radioimmunoassay showed that SLIGRL increased the release of CGRP and SP in WT but not TRPV1−/− hearts (P < 0.05), which were prevented by PKC-ε V1–2 and H-89. Thus our data show that PAR2 activation improves cardiac recovery after I/R injury in WT and TRPV1−/− hearts, with a greater effect in the former, suggesting that PAR2-mediated protection is TRPV1 dependent and independent, and that dysfunctional TRPV1 impairs PAR2 action. PAR2 activation of the PKC-ε or PKA pathway stimulates or sensitizes TRPV1 in WT hearts, leading to the release of CGRP and SP that contribute, at least in part, to PAR2-induced cardiac protection against I/R injury. PMID:19812353

Bio-Inspired Stretchable Network-Based Intelligent Composites

DTIC Science & Technology

2012-05-03

on par with that of lead zirconate titanate ( PZT ). This shows that the BSPT piezo-transducer has the potential to function in ultrasonic situations as...well as the PZTs typically used As a final test, the full network was used, with the same data acquisition computer, designed for PZT - based networks...ality of BSPT in SHM systems. These experiments indicate that BSPT has function- ality on par with PZT -5A and can simply replace the PZT in existing

Spatio-Temporal Convergence of Maximum Daily Light-Use Efficiency Based on Radiation Absorption by Canopy Chlorophyll

NASA Astrophysics Data System (ADS)

Zhang, Yao; Xiao, Xiangming; Wolf, Sebastian; Wu, Jin; Wu, Xiaocui; Gioli, Beniamino; Wohlfahrt, Georg; Cescatti, Alessandro; van der Tol, Christiaan; Zhou, Sha; Gough, Christopher M.; Gentine, Pierre; Zhang, Yongguang; Steinbrecher, Rainer; Ardö, Jonas

2018-04-01

Light-use efficiency (LUE), which quantifies the plants' efficiency in utilizing solar radiation for photosynthetic carbon fixation, is an important factor for gross primary production estimation. Here we use satellite-based solar-induced chlorophyll fluorescence as a proxy for photosynthetically active radiation absorbed by chlorophyll (APARchl) and derive an estimation of the fraction of APARchl (fPARchl) from four remotely sensed vegetation indicators. By comparing maximum LUE estimated at different scales from 127 eddy flux sites, we found that the maximum daily LUE based on PAR absorption by canopy chlorophyll (ɛmaxchl), unlike other expressions of LUE, tends to converge across biome types. The photosynthetic seasonality in tropical forests can also be tracked by the change of fPARchl, suggesting the corresponding ɛmaxchl to have less seasonal variation. This spatio-temporal convergence of LUE derived from fPARchl can be used to build simple but robust gross primary production models and to better constrain process-based models.

Trace-gas Spectroscopy of Methane on a Silicon Photonic Chip

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

Zhang, Eric; Xiong, Chi; Martin, Yves

Recent advances in hybrid integrated silicon photonic (SiPh) technologies are enabling the migration of conventional free-space optical spectroscopic sensors onto a compact on-chip platform [1-3]. In addition to the small spatial footprint and power efficiency, we envision such sensors to be scalably manufactured using existing CMOS-compatible foundry processes, thus providing disruptive SWaP-C (size, weight, power, and cost) benefits in contrast to commercially available optical sensors. Initial demonstration of evanescent TDLAS (tunable diode laser absorption spectroscopy) of methane (CH4) on a passive SiPh waveguide has indicated minimum fractional absorption of (αL)min = 3.3×10-5 Hz-1/2, which is on-par with state-of-art open-path TDLASmore » sensor systems [4]. Given the general recent movement toward cleaner fuels, CH4 fugitive emissions monitoring is of significant interest given the extremely high radiative forcing potential [5]. For a nominal waveguide length of 30 cm with Γ = 25 % evanescent exposure, this corresponds to ~ 10 ppmv detection sensitivity at 1 s integration time, and further sensitivity enhancement is expected with even longer waveguides, as the laser RIN typically dominates our measurements at nominal waveguide lengths. Despite the excellent sensitivities for short-term integration periods, long-term measurements (> 10 s) are potentially limited on a silicon platform due to the high material thermo-optic coefficient, resulting in significant susceptibility of Fabry-Perot etalons to drift in the presence of even small (~ 1 mK) thermal fluctuations. To this end, customized spectral fitting algorithms have played a significant role in both fringe drift mitigation and peak detection fidelity (e.g. in the presence of a passing CH4 plume), which are crucial for enhancing long-term stability without the need for frequent sensor recalibration. A variety of spectral algorithms have been designed for this purpose, and details will be presented at the meeting.« less

HepPar1-Positive Circulating Microparticles Are Increased in Subjects with Hepatocellular Carcinoma and Predict Early Recurrence after Liver Resection

PubMed Central

Abbate, Valeria; Marcantoni, Margherita; Giuliante, Felice; Vecchio, Fabio M.; Gatto, Ilaria; Mele, Caterina; Saviano, Antonio; Arciuolo, Damiano; Gaetani, Eleonora; Ferrari, Maria C.; Giarretta, Igor; Ardito, Francesco; Riccardi, Laura; Nicoletti, Alberto; Ponziani, Francesca R.; Gasbarrini, Antonio; Pompili, Maurizio; Pola, Roberto

2017-01-01

Circulating microparticles (MPs) are novel potential biomarkers in cancer patients. Their role in hepatocellular carcinoma (HCC) is under intensive investigation. In this study, we tested the hypothesis that MPs expressing the antigen HepPar1 are increased in the blood of subjects with HCC and may serve as markers of early recurrence after liver resection (LR). We studied 15 patients affected by HCC undergoing LR, and used flow cytometry to assess the number of circulating HepPar1+ MPs. Ten subjects without HCC (five with liver cirrhosis and five with healthy livers) were used as controls. After LR, HCC patients underwent a follow-up to check for early recurrence, which occurred in seven cases. The number of circulating HepPar1+ MPs was significantly higher in subjects affected by HCC, compared to individuals without cancer (p < 0.01). We also found that, among HCC patients, the number of circulating HepPar1+ MPs, measured before LR, was significantly higher in those who displayed early recurrence compared to those without recurrence (p = 0.02). Of note, other types of circulating MPs, such as those derived from endothelial cells (CD144+) or those produced by the activated endothelium (CD144+/CD62+), were not associated with HCC, nor could they predict HCC recurrence. HepPar1+ MPs deserve further investigation as novel biomarkers of disease and prognosis in HCC patients. PMID:28498353

Recombination changes at the boundaries of fully and partially sex-linked regions between closely related Silene species pairs

PubMed Central

Campos, J L; Qiu, S; Guirao-Rico, S; Bergero, R; Charlesworth, D

2017-01-01

The establishment of a region of suppressed recombination is a critical change during sex chromosome evolution, leading to such properties as Y (and W) chromosome genetic degeneration, accumulation of repetitive sequences and heteromorphism. Although chromosome inversions can cause large regions to have suppressed recombination, and inversions are sometimes involved in sex chromosome evolution, gradual expansion of the non-recombining region could potentially sometimes occur. We here test whether closer linkage has recently evolved between the sex-determining region and several genes that are partially sex-linked in Silene latifolia, using Silene dioica, a closely related dioecious plants whose XY sex chromosome system is inherited from a common ancestor. The S. latifolia pseudoautosomal region (PAR) includes several genes extremely closely linked to the fully Y-linked region. These genes were added to an ancestral PAR of the sex chromosome pair in two distinct events probably involving translocations of autosomal genome regions causing multiple genes to become partially sex-linked. Close linkage with the PAR boundary must have evolved since these additions, because some genes added in both events now show almost complete sex linkage in S. latifolia. We compared diversity patterns of five such S. latifolia PAR boundary genes with their orthologues in S. dioica, including all three regions of the PAR (one gene that was in the ancestral PAR and two from each of the added regions). The results suggest recent recombination suppression in S. latifolia, since its split from S. dioica. PMID:27827389

Cathepsin B and uPAR regulate self-renewal of glioma-initiating cells through GLI-regulated Sox2 and Bmi1 expression

PubMed Central

Rao, Jasti S.

2013-01-01

Cancer-initiating cells comprise a heterogeneous population of undifferentiated cells with the capacity for self-renewal and high proliferative potential. We investigated the role of uPAR and cathepsin B in the maintenance of stem cell nature in glioma-initiating cells (GICs). Simultaneous knockdown of uPAR and cathepsin B significantly reduced the expression of CD133, Nestin, Sox2 and Bmi1 at the protein level and GLI1 and GLI2 at the messenger RNA level. Also, knockdown of uPAR and cathepsin B resulted in a reduction in the number of GICs as well as sphere size. These changes are mediated by Sox2 and Bmi1, downstream of hedgehog signaling. Addition of cyclopamine reduced the expression of Sox2 and Bmi1 along with GLI1 and GLI2 expression, induced differentiation and reduced subsphere formation of GICs thereby indicating that hedgehog signaling acts upstream of Sox2 and Bmi1. Further confirmation was obtained from increased luciferase expression under the control of a GLI-bound Sox2 and Bmi1 luciferase promoter. Simultaneous knockdown of uPAR and cathepsin B also reduced the expression of Nestin Sox2 and Bmi1 in vivo. Thus, our study highlights the importance of uPAR and cathepsin B in the regulation of malignant stem cell self-renewal through hedgehog components, Bmi1 and Sox2. PMID:23222817

Inhibition of Protease-Activated Receptor (PAR1) Reduces Activation of the Endothelium, Coagulation, Fibrinolysis and Inflammation during Human Endotoxemia.

PubMed

Schoergenhofer, Christian; Schwameis, Michael; Gelbenegger, Georg; Buchtele, Nina; Thaler, Barbara; Mussbacher, Marion; Schabbauer, Gernot; Wojta, Johann; Jilma-Stohlawetz, Petra; Jilma, Bernd

2018-06-04

The protease-activated receptor-1 (PAR-1) is critically involved in the co-activation of coagulation and inflammatory responses. Vorapaxar is a reversible, orally active, low molecular weight, competitive antagonist of PAR-1.We investigated the effects of PAR-1 inhibition by vorapaxar on the inflammatory response, the activation of coagulation, fibrinolysis and endothelium during experimental endotoxemia. In this randomized, double blind, crossover trial, 16 healthy volunteers received a bolus infusion of 2 ng/kg lipopolysaccharide (LPS) ± placebo/vorapaxar with a washout period of 8 weeks. Vorapaxar dosing was guided by thrombin receptor-activating peptide-6-induced whole blood aggregometry. Participants received 10 mg vorapaxar or placebo as an initial dose and, depending on the aggregometry, potentially an additional 10 mg. Goal was > 80% inhibition of aggregation compared with baseline. Vorapaxar significantly reduced the LPS-induced increase in pro-thrombin fragments F1 + 2 by a median of 27% (quartiles: 11-49%), thrombin-anti-thrombin concentrations by 22% (-3 to 46%) and plasmin-anti-plasmin levels by 38% (23-53%). PAR-1 inhibition dampened peak concentrations of tumour necrosis factor -α, interleukin-6 and consequently C-reactive protein by 66% (-11-71%), 50% (15-79%) and 23% (16-38%), respectively. Vorapaxar decreased maximum von Willebrand factor levels by 29% (26-51%) and soluble E-selectin concentrations by 30% (25-38%) after LPS infusion. PAR-1 inhibition did not affect thrombomodulin, soluble P-selectin and platelet factor-4 concentrations.PAR-1 inhibition significantly reduced the activation of coagulation, fibrinolysis, the inflammatory response and endothelial activation during experimental human endotoxemia. Schattauer GmbH Stuttgart.

The relationship between levels of plasma-soluble urokinase plasminogen activator receptor (suPAR) and presence of migraine attack and aura.

PubMed

Yılmaz, Nigar; Yılmaz, Mustafa; Sirin, Burcu; Yılmaztekin, Sureyya; Kutlu, Gülnihal

2017-10-01

Migraine is one of the most common types of pain associated with sterile inflammatory conditions. Soluble urokinase plasminogen activator receptor (suPAR) is a potential novel inflammatory marker. We aim to determine the association between serum values of suPAR, procalcitonin, fibrinogen, and high-sensitivity C-reactive protein (hs-CRP) and migraine disease characteristics. The study involved a total of 60 migraine patients (33 patients in the interictal period, 27 patients in the attack period) and 30 healthy individuals. The serum values of suPAR were found to be significantly higher in migraine patients in the attack period than in migraine patients in the interictal period, and in healthy individuals (p < .01 for both). In addition, levels of suPAR were determined to be higher in migraine with aura patients than in migraine without aura patients. When we subdivided migraine patients according to frequency of attack (attacks/month), significant differences were found between the suPAR and procalcitonin levels (measured during the attack period) of those in the frequent-attack group (4-5 or more) versus those in the less frequent attack group (less than 4). Serum levels of procalcitonin were shown to be significantly higher in migraine patients during the attack period compared with migraine patients in the interictal period and in control subjects (p = .001 for both). Significant differences were found between plasma levels of fibrinogen in migraine patients versus control subjects (p < .01). No statistically significant difference was found between levels of hs-CRP in migraine patients versus the control group. These findings may show that presenting a high level of suPAR in migraine patients with attack and aura results to predisposition to occurring on the symptoms and that high levels of suPAR, procalcitonin and fibrinogen in patients with migraine result in neurogenic inflammation during migraine headaches.

Diallylsulfide attenuates excessive collagen production and apoptosis in a rat model of bleomycin induced pulmonary fibrosis through the involvement of protease activated receptor-2

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

Kalayarasan, Srinivasan, E-mail: kalaivasanbio@gmail.com; Sriram, Narayanan; Soumyakrishnan, Syamala

Pulmonary fibrosis (PF) can be a devastating lung disease. It is primarily caused by inflammation leading to severe damage of the alveolar epithelial cells. The pathophysiology of PF is not yet been clearly defined, but studying lung parenchymal injury by involving reactive oxygen species (ROS) through the activation of protease activated receptor-2 (PAR-2) may provide promising results. PAR-2 is a G-protein coupled receptor is known to play an important role in the development of PF. In this study, we investigated the inhibitory role of diallylsulfide (DAS) against ROS mediated activation of PAR-2 and collagen production accompanied by epithelial cell apoptosis.more » Bleomycin induced ROS levels may prompt to induce the expression of PAR-2 as well as extracellular matrix proteins (ECM), such as MMP 2 and 9, collagen specific proteins HSP-47, α-SMA, and cytokines IL-6, and IL-8RA. Importantly DAS treatment effectively decreased the expression of all these proteins. The inhibitory effect of DAS on profibrotic molecules is mediated by blocking the ROS level. To identify apoptotic signaling as a mediator of PF induction, we performed apoptotic protein expression, DNA fragmentation analysis and ultrastructural details of the lung tissue were performed. DAS treatment restored all these changes to near normalcy. In conclusion, treatment of PF bearing rats with DAS results in amelioration of the ROS production, PAR-2 activation, ECM production, collagen synthesis and alveolar epithelial cell apoptosis during bleomycin induction. We attained the first evidence that treatment of DAS decreases the ROS levels and may provide a potential therapeutic effect attenuating bleomycin induced PF. - Highlights: • DAS inhibits PAR-2 activity; bleomycin stimulates PAR-2 activity. • Increase in PAR-2 activity is correlated with pulmonary fibrosis • DAS reduces pro-inflammatory activity linked to facilitating pulmonary fibrosis. • DAS inhibits apoptosis of alveolar epithelial cells.« less

To Float or Not to Float: How Interactions between Light and Dissolved Inorganic Carbon Species Determine the Buoyancy of Stratiotes aloides

PubMed Central

Harpenslager, Sarah F.; Smolders, Alfons J. P.; Kieskamp, Ariët A. M.; Roelofs, Jan G. M.; Lamers, Leon P. M.

2015-01-01

Structural diversity formed by dense, floating Stratiotes aloides stands, generates hotspots of biodiversity of flora and fauna in wetlands. However, only part of the populations become emergent and provide this important facilitation. Since it has been hypothesised that its buoyancy depends on the rates of underwater photosynthesis, we investigated the role of dissolved CO2 availability and PAR on photosynthesis, biomass production and buoyancy in a controlled greenhouse experiment. Photosynthesis and growth were strongly influenced by both PAR and CO2 availability. At low PAR, plants formed less biomass and produced no emergent leaves, even when CO2 was abundant. At low CO2 levels, S. aloides switched to HCO3 - use, resulting in a lower photosynthetic O2 production, decreased emergent leaf formation and increased CaCO3 precipitation on its leaves, all of which impaired buoyancy. At high PAR, low CO2 availability resulted in slower colonisation of the water layer, whereas CO2 availability did not influence PAR-limited plants. Our study shows that site conditions, rather than the sole abundance of potentially facilitating species, may strongly determine whether or not they form the structure necessary to act as a facilitator for biodiversity in aquatic environments. PMID:25909504

Tolerance of chufa (Cyperus esculentus L.) plants, representing the higher plant compartment in bioregenerative life support systems, to super-optimal air temperatures

NASA Astrophysics Data System (ADS)

Shklavtsova, E. S.; Ushakova, S. A.; Shikhov, V. N.; Anishchenko, O. V.

2013-01-01

Plants intended to be included in the photosynthesizing compartment of the bioregenerative life support system (BLSS) need to be studied in terms of both their production parameters under optimal conditions and their tolerance to stress factors that might be caused by emergency situations. The purpose of this study was to investigate tolerance of chufa (Cyperus esculentus L.) plants to the super-optimal air temperature of 45 ± 1 °C as dependent upon PAR (photosynthetically active radiation) intensity and the duration of the exposure to the stress factor. Chufa plants were grown hydroponically, on expanded clay, under artificial light. The nutrient solution was Knop's mineral medium. Until the plants were 30 days old, they had been grown at 690 μmol m-2 s-1 PAR and air temperature 25 °C. Thirty-day-old plants were exposed to the temperature 45 °C for 6 h, 20 h, and 44 h at PAR intensities 690 μmol m-2 s-1 and 1150 μmol m-2 s-1. The exposure to the damaging air temperature for 44 h at 690 μmol m-2 s-1 PAR caused irreversible damage to PSA, resulting in leaf mortality. In chufa plants exposed to heat shock treatment at 690 μmol m-2 s-1 PAR for 6 h and 20 h, respiration exceeded photosynthesis, and CO2 release in the light was recorded. Functional activity of photosynthetic apparatus, estimated from parameters of pulse-modulated chlorophyll fluorescence in Photosystem 2 (PS 2), decreased 40% to 50%. After the exposure to the stress factor was finished, functional activity of PSA recovered its initial values, and apparent photosynthesis (Papparent) rate after a 20-h exposure to the stress factor was 2.6 times lower than before the elevation of the temperature. During the first hours of plant exposure to the temperature 45 °C at 1150 μmol m-2 s-1 PAR, respiration rate was higher than photosynthesis rate, but after 3-4 h of the exposure, photosynthetic processes exceeded oxidative ones and CO2 absorption in the light was recorded. At the end of the 6-h exposure, Papparent rate was close to that recorded prior to the exposure, and no significant changes were observed in the functional activity of PSA. At the end of the 20-h exposure, Papparent rate was close to its initial value, but certain parameters of the functional activity of PSA decreased 25% vs. their initial values. During the repair period, the parameters of external gas exchange recovered their initial values, and parameters of pulse-modulated chlorophyll fluorescence were 20-30% higher than their initial values. Thus, exposure of chufa plants to the damaging temperature of the air for 20 h did not cause any irreversible damage to the photosynthetic apparatus of plants at either 690 μmol m-2 s-1 or 1150 μmol m-2 s-1 PAR, and higher PAR intensity during the heat shock treatment enhanced heat tolerance of the plants.

Indigenous Storytelling and Participatory Action Research

PubMed Central

2015-01-01

Storytelling, in its various forms, has often been described as a practice with great emancipatory potential. In turn, Indigenous knowledge shows great promise in guiding a participatory action research (PAR) methodology. Yet these two approaches are rarely discussed in relation to one another, nor, has much been written in terms of how these two approaches may work synergistically toward a decolonizing research approach. In this article, I report on a community-driven knowledge translation activity, the Peoples’ International Health Tribunal, as an exemplar of how narrative and PAR approaches, guided by local Indigenous knowledge, have great potential to build methodologically and ethically robust research processes. Implications for building globally relevant research alliances and scholarship are further discussed, particularly in relation to working with Indigenous communities. PMID:28462305

Potential of Diesel Engine, Diesel Engine Design Concepts, Control Strategy and Implementation

DOT National Transportation Integrated Search

1980-03-01

Diesel engine design concepts and control system strategies are surveyed with application to passenger cars and light trucks. The objective of the study is to indicate the fuel economy potential of the technologies investigated. The engine design par...

Plasmid partition system of the P1par family from the pWR100 virulence plasmid of Shigella flexneri.

PubMed

Sergueev, Kirill; Dabrazhynetskaya, Alena; Austin, Stuart

2005-05-01

P1par family members promote the active segregation of a variety of plasmids and plasmid prophages in gram-negative bacteria. Each has genes for ParA and ParB proteins, followed by a parS partition site. The large virulence plasmid pWR100 of Shigella flexneri contains a new P1par family member: pWR100par. Although typical parA and parB genes are present, the putative pWR100parS site is atypical in sequence and organization. However, pWR100parS promoted accurate plasmid partition in Escherichia coli when the pWR100 Par proteins were supplied. Unique BoxB hexamer motifs within parS define species specificities among previously described family members. Although substantially different from P1parS from the P1 plasmid prophage of E. coli, pWR100parS has the same BoxB sequence. As predicted, the species specificity of the two types proved identical. They also shared partition-mediated incompatibility, consistent with the proposed mechanistic link between incompatibility and species specificity. Among several informative sequence differences between pWR100parS and P1parS is the presence of a 21-bp insert at the center of the pWR100parS site. Deletion of this insert left much of the parS activity intact. Tolerance of central inserts with integral numbers of helical DNA turns reflects the critical topology of these sites, which are bent by binding the host IHF protein.

Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis

PubMed Central

Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C Arnold

2015-01-01

Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced lung fibrosis is diminished in both PAR-1 and PAR-2 deficient mice. We thus have been suggested that combined inactivation of PAR-1 and PAR-2 would be more effective in blocking pulmonary fibrosis. Human and murine fibroblasts were stimulated with PAR-1 and PAR-2 agonists in the absence or presence of specific PAR-1 or PAR-2 antagonists after which fibrotic markers like collagen and smooth muscle actin were analysed by Western blot. Pulmonary fibrosis was induced by intranasal instillation of bleomycin into wild-type and PAR-2 deficient mice with or without a specific PAR-1 antagonist (P1pal-12). Fibrosis was assessed by hydroxyproline quantification and (immuno)histochemical analysis. We show that specific PAR-1 and/or PAR-2 activating proteases induce fibroblast migration, differentiation and extracellular matrix production. Interestingly, however, combined activation of PAR-1 and PAR-2 did not show any additive effects on these pro-fibrotic responses. Strikingly, PAR-2 deficiency as well as pharmacological PAR-1 inhibition reduced bleomycin-induced pulmonary fibrosis to a similar extent. PAR-1 inhibition in PAR-2 deficient mice did not further diminish bleomycin-induced pulmonary fibrosis. Finally, we show that the PAR-1-dependent pro-fibrotic responses are inhibited by the PAR-2 specific antagonist. Targeting PAR-1 and PAR-2 simultaneously is not superior to targeting either receptor alone in bleomycin-induced pulmonary fibrosis. We postulate that the pro-fibrotic effects of PAR-1 require the presence of PAR-2. PMID:25689283

Urokinase and its Receptors in Chronic Kidney Disease

PubMed Central

Zhang, Guoqiang; Eddy, Allison A.

2011-01-01

Since the recognition that plasminogen activator inhibitor-1 (PAI-1) is a powerful profibrotic molecule, there has been considerable interest in deciphering the extent to which this effect is mediated by its ability to inhibit serine proteases with downstream effects on fibrogenesis. This review will summarize current knowledge about the serine protease urokinase-type plasminogen activator and its high affinity receptor uPAR/CD87 as it pertains to chronic kidney disease (CKD) progression. An emerging theme is that the effects of PAI-1 and uPAR appear to be organ- and site-specific. Normal kidney tubules produce a large quantity of uPA that is secreted into the urinary space. Activity levels increase during CKD presumably due to new sources of production by macrophages and fibroblasts. By activating hepatocyte growth factor and degrading fibrinogen uPA may have anti-fibrotic effects. However CKD severity after experimental ureteral obstruction is not altered by endogenous uPA deficiency. Beneficial effects of exogenous uPA have been reported in experimental models of fibrosis in the lung and liver but CKD awaits exploration. Absent in normal kidneys uPAR is expressed by both renal parenchymal cells and inflammatory cells in a variety of pathological states. Such expression appears beneficial based on studies performed in uPAR-deficient mice. The uPAR promotes bacterial clearance in infectious diseases. In CKD uPAR expression is associated with high uPA activity but its most important effect appears to be due to scavenging activities and effects on cell recruitment and migration. Although uPAR itself is a non-signaling receptor, it interacts with a variety of co-receptors to modify cellular behavior. Best known are interactions with the low-density lipoprotein receptor-related protein (LRP-1) that lead to PAI-1 endocytosis and degradation, and interactions with several integrins to regulate matrix-dependent cell migration. Contacts with the receptor for the complement C5a component and the interleukin −6 receptor gp130 are examples of other recently recognized interactions. In addition to uPA, vitronectin and high molecular weight kininogen are alternate uPAR ligands that could be implicated in CKD progression. uPAR may also be shed from cell membranes. This soluble form (suPAR) has been detected in plasma and urine and is known to be a chemoattractant for leukocytes that express the formyl-peptide-receptor-like receptor 1/lipoxin A4 receptor. In addition to uPAR several other receptors, including some of the uPAR co-receptors, may also bind directly to uPA and activate cell signaling pathways. The roles of these newer uPAR ligands and uPA receptors are just beginning to be investigated. Since many of them are expressed in the kidney, their potential participation in CKD pathogenesis will be of interest. PMID:18508599

Immunoglobulin A with protease activity secreted in human milk activates PAR-2 receptors, of intestinal epithelial cells HT-29, and promotes beta-defensin-2 expression.

PubMed

Barrera, G J; Portillo, R; Mijares, A; Rocafull, M A; del Castillo, J R; Thomas, L E

2009-03-24

Secretory antibodies of the immunoglobulin A (sIgA) class constitute the first line of antigen-specific immune protection against pathogens and other antigens at mucosal surfaces. Although initially perceived as potentially deleterious, catalytic antibodies have been proposed to participate in the removal of metabolic wastes and in protection against infection. Here we show that the presence of sIgA endowed with serine protease-like hydrolytic activity in milk strongly correlates with PAR-2 activation in human intestinal epithelial cells. F(ab')(2) fragments of sIgA activated the epithelial cells in culture to produce beta-defensin-2 (hBD2). Intracellular Ca(2+) mobilization was induced by treatment with (1) sIgA-F(ab')(2) fragments; (2) trypsin, a recognized PAR-2 agonist; or (3) a synthetic PAR-2 agonist peptide (SLIGKV). The co-treatment with a synthetic PAR-2 antagonist peptide (FSLLRY) and sIgA-F(ab')(2) fragments eliminates the latter's effect; nevertheless, cells were not refractory to subsequent stimulation with sIgA-F(ab')(2) fragments. Both the induction of hBD-2 expression in epithelial cells and the increase in intracellular [Ca(2+)] stimulated by sIgA-F(ab')(2) fragments were inhibited by treatment with serine protease inhibitors or pertussis toxin (PTX). These findings suggest that catalytic antibodies can activate intestinal epithelial cells through G-protein-coupled PAR-2, and could actively participate in the immune system of breastfed babies inducing the production of peptides related to innate defense, such as defensins.

Activated protein C (APC) can increase bone anabolism via a protease-activated receptor (PAR)1/2 dependent mechanism.

PubMed

Shen, Kaitlin; Murphy, Ciara M; Chan, Ben; Kolind, Mille; Cheng, Tegan L; Mikulec, Kathy; Peacock, Lauren; Xue, Meilang; Park, Sang-Youel; Little, David G; Jackson, Chris J; Schindeler, Aaron

2014-12-01

Activated Protein C (APC) is an anticoagulant with strong cytoprotective properties that has been shown to promote wound healing. In this study APC was investigated for its potential orthopedic application using a Bone Morphogenetic Protein 2 (rhBMP-2) induced ectopic bone formation model. Local co-administration of 10 µg rhBMP-2 with 10 µg or 25 µg APC increased bone volume at 3 weeks by 32% (N.S.) and 74% (p<0.01) compared to rhBMP-2 alone. This was associated with a significant increase in CD31+ and TRAP+ cells in tissue sections of ectopic bone, consistent with enhanced vascularity and bone turnover. The actions of APC are largely mediated by its receptors endothelial protein C receptor (EPCR) and protease-activated receptors (PARs). Cultured pre-osteoblasts and bone nodule tissue sections were shown to express PAR1/2 and EPCR. When pre-osteoblasts were treated with APC, cell viability and phosphorylation of ERK1/2, Akt, and p38 were increased. Inhibition with PAR1 and sometimes PAR2 antagonists, but not with EPCR blocking antibodies, ameliorated the effects of APC on cell viability and kinase phosphorylation. These data indicate that APC can affect osteoblast viability and signaling, and may have in vivo applications with rhBMP-2 for bone repair. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis.

PubMed

Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C Arnold

2015-06-01

Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced lung fibrosis is diminished in both PAR-1 and PAR-2 deficient mice. We thus have been suggested that combined inactivation of PAR-1 and PAR-2 would be more effective in blocking pulmonary fibrosis. Human and murine fibroblasts were stimulated with PAR-1 and PAR-2 agonists in the absence or presence of specific PAR-1 or PAR-2 antagonists after which fibrotic markers like collagen and smooth muscle actin were analysed by Western blot. Pulmonary fibrosis was induced by intranasal instillation of bleomycin into wild-type and PAR-2 deficient mice with or without a specific PAR-1 antagonist (P1pal-12). Fibrosis was assessed by hydroxyproline quantification and (immuno)histochemical analysis. We show that specific PAR-1 and/or PAR-2 activating proteases induce fibroblast migration, differentiation and extracellular matrix production. Interestingly, however, combined activation of PAR-1 and PAR-2 did not show any additive effects on these pro-fibrotic responses. Strikingly, PAR-2 deficiency as well as pharmacological PAR-1 inhibition reduced bleomycin-induced pulmonary fibrosis to a similar extent. PAR-1 inhibition in PAR-2 deficient mice did not further diminish bleomycin-induced pulmonary fibrosis. Finally, we show that the PAR-1-dependent pro-fibrotic responses are inhibited by the PAR-2 specific antagonist. Targeting PAR-1 and PAR-2 simultaneously is not superior to targeting either receptor alone in bleomycin-induced pulmonary fibrosis. We postulate that the pro-fibrotic effects of PAR-1 require the presence of PAR-2. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Indigenous Storytelling and Participatory Action Research: Allies Toward Decolonization? Reflections From the Peoples' International Health Tribunal.

PubMed

Caxaj, C Susana

2015-01-01

Storytelling, in its various forms, has often been described as a practice with great emancipatory potential. In turn, Indigenous knowledge shows great promise in guiding a participatory action research (PAR) methodology. Yet these two approaches are rarely discussed in relation to one another, nor, has much been written in terms of how these two approaches may work synergistically toward a decolonizing research approach. In this article, I report on a community-driven knowledge translation activity, the Peoples' International Health Tribunal, as an exemplar of how narrative and PAR approaches, guided by local Indigenous knowledge, have great potential to build methodologically and ethically robust research processes. Implications for building globally relevant research alliances and scholarship are further discussed, particularly in relation to working with Indigenous communities.

Effect of mild temperature shift on poly(ADP-ribose) and γH2AX levels in cultured cells

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

Yamashita, Sachiko; Tanaka, Masakazu; Sato, Teruaki

Poly (ADP-ribose) (PAR) is rapidly synthesized by PAR polymerases (PARPs) upon activation by DNA single- and double-strand breaks. In this study, we examined the quantitative amount of PAR in HeLa cells cultured within the physiological temperatures below 41 °C for verification of the effect of shifting-up or -down the temperature from 37.0 °C on the DNA breaks, whether the temperature-shift caused breaks that could be monitored by the level of PAR. While PAR level did not change significantly when HeLa cells were cultured at 33.5 °C or 37.0 °C, it was significantly increased 2- and 3-fold when cells were cultured for 12 h andmore » 24 h, respectively, at 40.5 °C as compared to 37.0 °C. Similar to the results with HeLa cells, PAR level was increased 2-fold in CHO-K1 cells cultured at 40.5 °C for 24 h as compared to 37.0 °C. As the cellular levels of PAR polymerase1 (PARP1) and PAR glycohydrolase (PARG), a major degradation enzyme for PAR, did not seem to change significantly, this increase could be caused by activation of PARP1 by DNA strand breaks. In fact, γH2AX, claimed to be a marker of DNA double-strand breaks, was found in cell extracts of HeLa cells and CHO-K1 cells at elevated temperature vs. 37.0 °C, and these γH2AX signals were intensified in the presence of 3-aminobenzamide, a PARP inhibitor. The γH2AX immunohistochemistry results in HeLa cells were consistent with Western blot analyses. In HeLa cells, proliferation was significantly suppressed at 40.5 °C in 72 h-continuous cultures and decreased viabilities were also observed after 24–72 h at 40.5 °C. Flow cytometric analyses showed that the HeLa cells were arrested at G2/M after temperature shift-up to 40.5 °C. These physiological changes were potentiated in the presence of 3-aminobenzamide. Decrease in growth rates, increased cytotoxicity and G2/M arrest, were associated with the temperature-shift to 40.5 °C and are indirect evidence of DNA breaks. In addition to γH2AX, PAR could be a sensitive marker for DNA single- and double-strand breaks. These two molecular markers provide evidence of physiological changes occurring within cells. - Highlights: • Physiological level of poly(ADP-ribose) was determined during mild temperature shift. • Poly(ADP-ribose) level in HeLa and CHO-K1 cells significantly increased. • γH2AX signals increased during culture at 40.5 °C as compared to 37.0 °C. • Poly(ADP-ribose) polymerase inhibitor potentiated γH2AX signals at 40.5 °C. • γH2AX and poly(ADP-ribose) level provide evidence of physiological changes in cells.« less

Expression of protease-activated receptor (PAR)-2, but not other PARs, is regulated by inflammatory cytokines in rat astrocytes.

PubMed

Sokolova, Elena; Aleshin, Stepan; Reiser, Georg

2012-02-01

Protease-activated receptors (PARs) are widely expressed in the central nervous system (CNS) and are believed to play an important role in normal brain functioning as well as in development of various inflammatory and neurodegenerative disorders. Pathological conditions cause altered expression of PARs in brain cells and therefore altered responsiveness to PAR activation. The exact mechanisms of regulation of PAR expression are not well studied. Here, we evaluated in rat astrocytes the influence of LPS, pro-inflammatory cytokines TNFα and IL-1β and continuous PAR activation by PAR agonists on the expression levels of PARs. These stimuli are important in inflammatory and neurological disorders, where their levels are increased. We report that LPS as well as cytokines TNFα and IL-1β affected only the PAR-2 level, but their effects were opposite. LPS and TNFα increased the functional expression of PAR-2, whereas IL-1β down-regulated the functional response of PAR-2. Agonists of PAR-1 specifically increased mRNA level of PAR-2, but not protein level. Transcript levels of other PARs were not changed after PAR-1 activation. Stimulation of the cells with PAR-2 or PAR-4 agonists did not alter PAR levels. We found that up-regulation of PAR-2 is dependent on PKC activity, mostly via its Ca²⁺-sensitive isoforms. Two transcription factors, NFκB and AP-1, are involved in up-regulation of PAR-2. These findings provide new information about the regulation of expression of PAR subtypes in brain cells. This is of importance for targeting PARs, especially PAR-2, for the treatment of CNS disorders. Copyright © 2011 Elsevier Ltd. All rights reserved.

Contributions of protein kinases and β-arrestin to termination of protease-activated receptor 2 signaling.

PubMed

Jung, Seung-Ryoung; Seo, Jong Bae; Deng, Yi; Asbury, Charles L; Hille, Bertil; Koh, Duk-Su

2016-03-01

Activated Gq protein-coupled receptors (GqPCRs) can be desensitized by phosphorylation and β-arrestin binding. The kinetics and individual contributions of these two mechanisms to receptor desensitization have not been fully distinguished. Here, we describe the shut off of protease-activated receptor 2 (PAR2). PAR2 activates Gq and phospholipase C (PLC) to hydrolyze phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol and inositol trisphosphate (IP3). We used fluorescent protein-tagged optical probes to monitor several consequences of PAR2 signaling, including PIP2 depletion and β-arrestin translocation in real time. During continuous activation of PAR2, PIP2 was depleted transiently and then restored within a few minutes, indicating fast receptor activation followed by desensitization. Knockdown of β-arrestin 1 and 2 using siRNA diminished the desensitization, slowing PIP2 restoration significantly and even adding a delayed secondary phase of further PIP2 depletion. These effects of β-arrestin knockdown on PIP2 recovery were prevented when serine/threonine phosphatases that dephosphorylate GPCRs were inhibited. Thus, PAR2 may continuously regain its activity via dephosphorylation when there is insufficient β-arrestin to trap phosphorylated receptors. Similarly, blockers of protein kinase C (PKC) and G protein-coupled receptor kinase potentiated the PIP2 depletion. In contrast, an activator of PKC inhibited receptor activation, presumably by augmenting phosphorylation of PAR2. Our interpretations were strengthened by modeling. Simulations supported the conclusions that phosphorylation of PAR2 by protein kinases initiates receptor desensitization and that recruited β-arrestin traps the phosphorylated state of the receptor, protecting it from phosphatases. Speculative thinking suggested a sequestration of phosphatidylinositol 4-phosphate 5 kinase (PIP5K) to the plasma membrane by β-arrestin to explain why knockdown of β-arrestin led to secondary depletion of PIP2. Indeed, artificial recruitment of PIP5K removed the secondary loss of PIP2 completely. Altogether, our experimental and theoretical approaches demonstrate roles and dynamics of the protein kinases, β-arrestin, and PIP5K in the desensitization of PAR2. © 2016 Jung et al.

Contributions of protein kinases and β-arrestin to termination of protease-activated receptor 2 signaling

PubMed Central

Jung, Seung-Ryoung; Seo, Jong Bae; Deng, Yi; Asbury, Charles L.; Hille, Bertil

2016-01-01

Activated Gq protein–coupled receptors (GqPCRs) can be desensitized by phosphorylation and β-arrestin binding. The kinetics and individual contributions of these two mechanisms to receptor desensitization have not been fully distinguished. Here, we describe the shut off of protease-activated receptor 2 (PAR2). PAR2 activates Gq and phospholipase C (PLC) to hydrolyze phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol and inositol trisphosphate (IP3). We used fluorescent protein–tagged optical probes to monitor several consequences of PAR2 signaling, including PIP2 depletion and β-arrestin translocation in real time. During continuous activation of PAR2, PIP2 was depleted transiently and then restored within a few minutes, indicating fast receptor activation followed by desensitization. Knockdown of β-arrestin 1 and 2 using siRNA diminished the desensitization, slowing PIP2 restoration significantly and even adding a delayed secondary phase of further PIP2 depletion. These effects of β-arrestin knockdown on PIP2 recovery were prevented when serine/threonine phosphatases that dephosphorylate GPCRs were inhibited. Thus, PAR2 may continuously regain its activity via dephosphorylation when there is insufficient β-arrestin to trap phosphorylated receptors. Similarly, blockers of protein kinase C (PKC) and G protein–coupled receptor kinase potentiated the PIP2 depletion. In contrast, an activator of PKC inhibited receptor activation, presumably by augmenting phosphorylation of PAR2. Our interpretations were strengthened by modeling. Simulations supported the conclusions that phosphorylation of PAR2 by protein kinases initiates receptor desensitization and that recruited β-arrestin traps the phosphorylated state of the receptor, protecting it from phosphatases. Speculative thinking suggested a sequestration of phosphatidylinositol 4-phosphate 5 kinase (PIP5K) to the plasma membrane by β-arrestin to explain why knockdown of β-arrestin led to secondary depletion of PIP2. Indeed, artificial recruitment of PIP5K removed the secondary loss of PIP2 completely. Altogether, our experimental and theoretical approaches demonstrate roles and dynamics of the protein kinases, β-arrestin, and PIP5K in the desensitization of PAR2. PMID:26927499

A new class of orthosteric uPAR·uPA small-molecule antagonists are allosteric inhibitors of the uPAR·vitronectin interaction.

PubMed

Liu, Degang; Zhou, Donghui; Wang, Bo; Knabe, William Eric; Meroueh, Samy O

2015-06-19

The urokinase receptor (uPAR) is a GPI-anchored cell surface receptor that is at the center of an intricate network of protein-protein interactions. Its immediate binding partners are the serine proteinase urokinase (uPA), and vitronectin (VTN), a component of the extracellular matrix. uPA and VTN bind at distinct sites on uPAR to promote extracellular matrix degradation and integrin signaling, respectively. Here, we report the discovery of a new class of pyrrolone small-molecule inhibitors of the tight ∼1 nM uPAR·uPA protein-protein interaction. These compounds were designed to bind to the uPA pocket on uPAR. The highest affinity compound, namely 7, displaced a fluorescently labeled α-helical peptide (AE147-FAM) with an inhibition constant Ki of 0.7 μM and inhibited the tight uPAR·uPAATF interaction with an IC50 of 18 μM. Biophysical studies with surface plasmon resonance showed that VTN binding is highly dependent on uPA. This cooperative binding was confirmed as 7, which binds at the uPAR·uPA interface, also inhibited the distal VTN·uPAR interaction. In cell culture, 7 blocked the uPAR·uPA interaction in uPAR-expressing human embryonic kidney (HEK-293) cells and impaired cell adhesion to VTN, a process that is mediated by integrins. As a result, 7 inhibited integrin signaling in MDA-MB-231 cancer cells as evidenced by a decrease in focal adhesion kinase (FAK) phosphorylation and Rac1 GTPase activation. Consistent with these results, 7 blocked breast MDA-MB-231 cancer cell invasion with IC50 values similar to those observed in ELISA and surface plasmon resonance competition studies. Explicit-solvent molecular dynamics simulations show that the cooperativity between uPA and VTN is attributed to stabilization of uPAR motion by uPA. In addition, free energy calculations revealed that uPA stabilizes the VTNSMB·uPAR interaction through more favorable electrostatics and entropy. Disruption of the uPAR·VTNSMB interaction by 7 is consistent with the cooperative binding to uPAR by uPA and VTN. Interestingly, the VTNSMB·uPAR interaction was less favorable in the VTNSMB·uPAR·7 complex suggesting potential cooperativity between 7 and VTN. Compound 7 provides an excellent starting point for the development of more potent derivatives to explore uPAR biology.

Coherent population trapping with a controlled dissipation: applications in optical metrology

NASA Astrophysics Data System (ADS)

Nicolas, L.; Delord, T.; Jamonneau, P.; Coto, R.; Maze, J.; Jacques, V.; Hétet, G.

2018-03-01

We analyze the properties of a pulsed coherent population trapping protocol that uses a controlled decay from the excited state in a Λ-level scheme. We study this problem analytically and numerically and find regimes where narrow transmission, absorption, or fluorescence spectral lines occur. We then look for optimal frequency measurements using these spectral features by computing the Allan deviation in the presence of ground state decoherence and show that the protocol is on a par with Ramsey-CPT. We discuss possible implementations with ensembles of alkali atoms and single ions and demonstrate that typical pulsed-CPT experiments that are realized on femto-second timescales can be implemented on micro-seconds timescales using this scheme.

Low clouds and cloud immersion enhance photosynthesis in understory species of a southern Appalachian spruce-fir forest (USA).

PubMed

Johnson, Daniel M; Smith, William K

2006-11-01

High-altitude forests of the southern Appalachian Mountains (USA) are frequently immersed in clouds, as are many mountain forests. They may be particularly sensitive to predicted increases in cloud base altitude with global warming. However, few studies have addressed the impacts of immersion on incident sunlight and photosynthesis. Understory sunlight (photosynthetically active radiation, PAR) was measured during clear, low cloud, and cloud-immersed conditions at Mount Mitchell and Roan Mountain, NC (USA) along with accompanying photosynthesis in four representative understory species. Understory PAR was substantially less variable on immersed vs. clear days. Photosynthesis became light-saturated between ∼100 and 400 μmol · m(-2) · s(-1) PAR for all species measured, corresponding closely to the sunlight environment measured during immersion. Estimated daily carbon gain was 26% greater on clear days at a more open canopy site but was 22% greater on immersed/cloudy days at a more closed canopy site. F(v)/F(m) (maximum photosystem II efficiency) in Abies fraseri seedlings exposed to 2.5 min full sunlight was significantly reduced (10%), indicating potential reductions in photosynthesis on clear days. In addition, photosynthesis in microsites with canopy cover was nearly 3-fold greater under immersed (2.6 mmol · m(-2) · h(-1)) vs. clear conditions (0.9 mmol · m(-2) · h(-1)). Thus, cloud immersion provided more constant PAR regimes that enhanced photosynthesis, especially in shaded microsites. Future studies are needed to predict the survival of these refugial forests under potential changes in cloud regimes.

Matrix metalloproteinase-2: A key regulator in coagulation proteases mediated human breast cancer progression through autocrine signaling.

PubMed

Das, Kaushik; Prasad, Ramesh; Ansari, Shabbir Ahmed; Roy, Abhishek; Mukherjee, Ashis; Sen, Prosenjit

2018-06-02

Cell invasion is attributed to the synthesis and secretion of proteolytically active matrix-metalloproteinases (MMPs) by tumor cells to degrade extracellular matrix (ECM) and promote metastasis. The role of protease-activated receptor 2 (PAR2) in human breast cancer migration/invasion via MMP-2 up-regulation remains ill-defined; hence we investigated whether TF-FVIIa/trypsin-mediated PAR2 activation induces MMP-2 expression in human breast cancer. MMP-2 expression and the signaling mechanisms were analyzed by western blotting and RT-PCR. MMP-2 activity was measured by gelatin zymography. Cell invasion was analyzed by transwell invasion assay whereas; wound healing assay was performed to understand the cell migratory potential. Here, we highlight that TF-FVIIa/trypsin-mediated PAR2 activation leads to enhanced MMP-2 expression in human breast cancer cells contributing to tumor progression. Knock-down of PAR2 abrogated TF-FVIIa/trypsin-induced up-regulation of MMP-2. Again, genetic manipulation of AKT or inhibition of NF-ĸB suggested that PAR2-mediated enhanced MMP-2 expression is dependent on the PI3K-AKT-NF-ĸB pathway. We also reveal that TF, PAR2, and MMP-2 are over-expressed in invasive breast carcinoma tissues as compared to normal. Knock-down of MMP-2 significantly impeded TF-FVIIa/trypsin-induced cell invasion. Further, we report that MMP-2 activates p38 MAPK-MK2-HSP27 signaling axis that leads to actin polymerization and induces cell migration. Pharmacological inhibition of p38 MAPK or MK2 attenuates MMP-2-induced cell migration. The study delineates a novel signaling pathway by which PAR2-induced MMP-2 expression regulates human breast cancer cell migration/invasion. Understanding these mechanistic details will certainly help to identify crucial targets for therapeutic interventions in breast cancer metastasis. Copyright © 2018. Published by Elsevier Masson SAS.

Psychometric properties of the newly translated creole multidimensional scale of perceived social support (MSPSS) and perceived adequacy of resource scale (PARS) and the relationship between perceived social support and resources in Haitian mothers in the US.

PubMed

Hannan, Jean; Alce, Marise; Astros, Adrian

2016-02-09

Low income postpartum mothers with little to no social support have increased maternal and infant morbidity and mortality, especially those with limited English proficiency and limited accesses to resources. Haitians, a growing minority in the US are an understudied population excluded from most studies due to the lack of instruments in Creole. The most widely used instruments for measuring social support, the Multidimensional Scale of Perceived Social Support (MSPSS) and Perceived Adequacy of Resource Scale (PARS), are not available in Creole. Currently, there are no published studies on the psychometric properties of the MSPSS or the PARS in Creole. Data from Haitian mothers are needed to identify potential postpartum mothers and infants most at risk of developing adverse maternal and infant outcomes from a lack of social support and perceived resources. The purpose of this study is to test the psychometrics of the newly-translated Creole instruments of the MSPSS and PARS with a sample of bilingual (Creole/English) mothers. The MSPSS and PARS were translated and back translated from English to Creole. The adapted Creole versions of the instruments were tested using a convenience sample. A total of 85 Haitian mothers' completed both instruments in Creole and English 2 weeks apart. Internal consistency reliability and stability were strong for both the MSPSS and PARS (.91-.99). The two instruments had strong reliability and validity for the translated Creole versions and similar to the English versions. The MSPSS and PARS are a valid measure of perceived social support and resources. Psychometric findings suggest that the newly translated Creole versions are good representations of the English versions indicating the translation process was successful. The newly translated instruments available in Creole provide non-English speaking Haitian mothers the opportunity to participate in studies.

Soluble Urokinase-Type Plasminogen Activator Receptor Improves Risk Prediction in Patients With Chronic Heart Failure.

PubMed

Koller, Lorenz; Stojkovic, Stefan; Richter, Bernhard; Sulzgruber, Patrick; Potolidis, Christos; Liebhart, Florian; Mörtl, Deddo; Berger, Rudolf; Goliasch, Georg; Wojta, Johann; Hülsmann, Martin; Niessner, Alexander

2017-04-01

This study investigated the predictive value of soluble urokinase-type plasminogen activator receptor (suPAR) in patients with chronic heart failure (CHF). SuPAR originates from proteolytic cleavage of the membrane-bound receptor from activated immune and endothelial cells and reflects the level of immune activation. As inflammation plays a crucial role in the complex pathophysiology of CHF, we hypothesized that suPAR might be a suitable prognostic biomarker in patients with CHF. SuPAR levels were determined in 319 patients with CHF admitted to our outpatient department for heart failure and in a second cohort consisting of 346 patients with CHF, for validation. During a median follow-up time of 3.2 years, 119 patients (37.3%) died. SuPAR was a strong predictor of mortality with a crude hazard ratio (HR) per increase of 1 SD (HR per 1 SD) of 1.96 (95% confidence interval [CI]: 1.63 to 2.35; p < 0.001) in univariate analysis and remained significant after comprehensive multivariate adjustment with an adjusted HR per 1 SD of 1.38 (95% CI: 1.04 to 1.83; p = 0.026). SuPAR added prognostic value beyond the multivariate model indicated by improvements in C-statistics (area under the curve: 0.72 vs 0.74, respectively; p = 0.02), the category-free net reclassification index (24.9%; p = 0.032), and the integrated discrimination improvement (0.011; p = 0.05). Validation in the second cohort yielded consistent results. SuPAR is a strong and independent predictor of mortality in patients with CHF, potentially suitable to refine risk assessment in this vulnerable group of patients. Our results emphasize the impact of immune activation on survival in patients with CHF. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system.

PubMed

Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

2015-12-22

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos-an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

Ezetimibe inhibits platelet activation and uPAR expression on endothelial cells.

PubMed

Becher, Tobias; Schulze, Torsten J; Schmitt, Melanie; Trinkmann, Frederik; El-Battrawy, Ibrahim; Akin, Ibrahim; Kälsch, Thorsten; Borggrefe, Martin; Stach, Ksenija

2017-01-15

Lipid lowering therapy constitutes the basis of cardiovascular disease therapy. The purpose of this study was to investigate effects of ezetimibe, a selective inhibitor of intestinal cholesterol absorption, on platelets and endothelial cells in an in vitro endothelial cell model. After a 24h incubation period with ezetimibe (concentrations 1, 50, 100 and 1000ng/ml), human umbilical vein endothelial cells (HUVEC) were stimulated for 1h with lipopolysaccharide (LPS) and were then incubated in direct contact with activated platelets. Following this, the expression of CD40L and CD62P on platelets, and the expression of ICAM-1, VCAM-1, uPAR, and MT1-MMP on endothelial cells were measured by flow cytometry. Supernatants were analysed by enzyme linked immunosorbent assay for soluble MCP-1, IL-6 and MMP-1. The increased expression of uPAR on endothelial cells by proinflammatory stimulation with LPS and by direct endothelial contact with activated platelets was significantly reduced through pre-incubation with 100ng/ml and 1000ng/ml ezetimibe (p<0.05). Platelets directly incubated with ezetimibe but without endothelial cell contact showed significantly reduced CD62P and CD40L surface expression (p<0.05). Ezetimibe had no significant effects on HUVEC expression of MT1-MMP, ICAM-1 and VCAM-1 and on CD40L expression on platelets in direct contact with endothelial cells. Levels of soluble IL-6 in HUVEC supernatants were significantly lower after pre-incubation with ezetimibe. In this in vitro analysis, ezetimibe directly attenuates platelet activation and has significant endothelial cell mediated effects on selected markers of atherosclerosis. Copyright © 2016. Published by Elsevier Ireland Ltd.

Time-dependent upregulation of electron transport with concomitant induction of regulated excitation dissipation in Haslea diatoms.

PubMed

Perkins, R; Williamson, C; Lavaud, J; Mouget, J-L; Campbell, D A

2018-04-16

Photoacclimation by strains of Haslea "blue" diatom species H. ostrearia and H. silbo sp. nov. ined. was investigated with rapid light curves and induction-recovery curves using fast repetition rate fluorescence. Cultures were grown to exponential phase under 50 µmol m -2  s -1 photosynthetic available radiation (PAR) and then exposed to non-sequential rapid light curves where, once electron transport rate (ETR) had reached saturation, light intensity was decreased and then further increased prior to returning to near growth light intensity. The non-sequential rapid light curve revealed that ETR was not proportional to the instantaneously applied light intensity, due to rapid photoacclimation. Changes in the effective absorption cross sections for open PSII reaction centres (σ PSII ') or reaction centre connectivity (ρ) did not account for the observed increases in ETR under extended high light. σ PSII ' in fact decreased as a function of a time-dependent induction of regulated excitation dissipation Y(NPQ), once cells were at or above a PAR coinciding with saturation of ETR. Instead, the observed increases in ETR under extended high light were explained by an increase in the rate of PSII reopening, i.e. Q A - oxidation. This acceleration of electron transport was strictly light dependent and relaxed within seconds after a return to low light or darkness. The time-dependent nature of ETR upregulation and regulated NPQ induction was verified using induction-recovery curves. Our findings show a time-dependent induction of excitation dissipation, in parallel with very rapid photoacclimation of electron transport, which combine to make ETR independent of short-term changes in PAR. This supports a selective advantage for these diatoms when exposed to fluctuating light in their environment.

UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

NASA Astrophysics Data System (ADS)

Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

2013-04-01

Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV (ultraviolet) radiation and PAR (photosynthetically active radiation) diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of both UV and PAR solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. While the Mackenzie input is the main driver of CDOM dynamics in low salinity waters, locally, primary production can create significant increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that ∼16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. The discharges of DOC and its chromophoric subset (CDOM) by the Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence excitation/emission matrix spectroscopy (EEMS) and parallel factor (PARAFAC) analysis. Our results showed an aquatic dissolved organic matter (DOM) component (C1), probably produced in the numerous lakes of the watershed, that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta Sector. This aquatic DOM could partially explain the high CDOM spectral slopes observed in the Beaufort Sea.

ParABS Systems of the Four Replicons of Burkholderia cenocepacia: New Chromosome Centromeres Confer Partition Specificity†

PubMed Central

Dubarry, Nelly; Pasta, Franck; Lane, David

2006-01-01

Most bacterial chromosomes carry an analogue of the parABS systems that govern plasmid partition, but their role in chromosome partition is ambiguous. parABS systems might be particularly important for orderly segregation of multipartite genomes, where their role may thus be easier to evaluate. We have characterized parABS systems in Burkholderia cenocepacia, whose genome comprises three chromosomes and one low-copy-number plasmid. A single parAB locus and a set of ParB-binding (parS) centromere sites are located near the origin of each replicon. ParA and ParB of the longest chromosome are phylogenetically similar to analogues in other multichromosome and monochromosome bacteria but are distinct from those of smaller chromosomes. The latter form subgroups that correspond to the taxa of their hosts, indicating evolution from plasmids. The parS sites on the smaller chromosomes and the plasmid are similar to the “universal” parS of the main chromosome but with a sequence specific to their replicon. In an Escherichia coli plasmid stabilization test, each parAB exhibits partition activity only with the parS of its own replicon. Hence, parABS function is based on the independent partition of individual chromosomes rather than on a single communal system or network of interacting systems. Stabilization by the smaller chromosome and plasmid systems was enhanced by mutation of parS sites and a promoter internal to their parAB operons, suggesting autoregulatory mechanisms. The small chromosome ParBs were found to silence transcription, a property relevant to autoregulation. PMID:16452432

Protease-activated receptor 1 and 2 contribute to angiotensin II-induced activation of adventitial fibroblasts from rat aorta

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

He, Rui-Qing; Tang, Xiao-Feng; Zhang, Bao-Li

Adventitial fibroblasts (AFs) can be activated by angiotensin II (Ang II) and exert pro-fibrotic and pro-inflammatory effects in vascular remodeling. Protease-activated receptor (PAR) 1 and 2 play a significant role in fibrogenic and inflammatory diseases. The present study hypothesized that PAR1 and PAR2 are involved in Ang II-induced AF activation and contribute to adventitial remodeling. We found that direct activation of PAR1 and PAR2 with PAR1-AP and PAR2-AP led to AF activation, including proliferation and differentiation of AFs, extracellular matrix synthesis, as well as production of pro-fibrotic cytokine TGF-β and pro-inflammatory cytokines IL-6 and MCP-1. Furthermore, PAR1 and PAR2 mediatedmore » Ang II-induced AF activation, since both PAR1 and PAR2 antagonists inhibited Ang II-induced proliferation, migration, differentiation, extracellular matrix synthesis and production of pro-fibrotic and pro-inflammatory cytokines in AFs. Finally, mechanistic study showed that Ang II, via Ang II type I receptor (AT1R), upregulated both PAR1 and PAR2 expression, and transactivated PAR1 and PAR2, as denoted by internalization of both proteins. In conclusion, our results suggest that PAR1 and PAR2 play a critical role in Ang II-induced AF activation, and this may contribute to adventitia-related pathological changes. - Highlights: • Direct activation of PAR1 and PAR2 led to adventitial fibroblast (AF) activation. • PAR1 and PAR2 antagonists attenuated Ang II-induced AF activation. • Ang II induced the upregulation and transactivation of PAR1/PAR2 in AFs.« less

Omnidirectional polarization insensitive tunable absorption in graphene metamaterial of nanodisk structure

NASA Astrophysics Data System (ADS)

Ning, Renxia; Bao, Jie; Jiao, Zheng; Xu, Yuan

2015-11-01

Tunable absorption based on graphene metamaterial with nanodisk structure at near-infrared frequency was investigated using the finite difference time domain method. The absorption of the nanodisk structure which consisting of Au-MgF2-graphene-Au-polyimide (from bottom to top) can be tuned by the chemical potential of graphene at certain diameter of nanodisk. The permittivity of graphene is discussed with different chemical potential to obtain tunable absorption. It is shown that the increased value of the chemical potential of graphene can lead to blue-shifted of the absorption peaks and the values decreased. Moreover, dual-band and triple-band absorption can be achieved for resonance frequencies at normal incidence. Compared with diameter of nanodisks, the multilayer structure shows multi-band absorber, and an omnidirectional absorption at 195.25 THz is insensitive to TE/TM polarization. This omnidirectional polarization insensitive absorption may be applied by optical communications such as optical absorber, near infrared stealth, and filter.

A spectrophotometric assay method for vanadium in biological and environmental samples using 2,4-dinitrophenylhydrazine with imipramine hydrochloride.

PubMed

Al-Tayar, Naef Ghllab Saeed; Nagaraja, P; Vasantha, R A; Shresta, Ashwinee Kumar

2012-01-01

A simple, rapid, and sensitive method involving the interaction of 2,4-dinitrophenylhydrazine with imipramine hydrochloride in presence of vanadium (V) in sulfuric acid medium has been proposed for the determination of vanadium. The purple-colored product developed showed an absorption maximum at 560 nm and was stable for 24 h. The working curve was linear over the concentration range of 0.1-2.8 μg ml( - 1), with sensitivity of detection of 0.0124 μg ml( - 1). Molar absorptivity and Sandell's sensitivity were found to be 2.6 × 10(4) l/mol cm and 0.0039 μg cm( - 1), respectively. The accuracy of the proposed method was assessed by Student's t test and variance ratio F test, and the results were on par with the reported method. The method was successfully used in the determination of V in water, human urine, soil, and plant samples, and it was free from interference by various concomitant ions.

Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

PubMed

Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

2017-11-01

A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Estimation of the Young's modulus of the human pars tensa using in-situ pressurization and inverse finite-element analysis.

PubMed

Rohani, S Alireza; Ghomashchi, Soroush; Agrawal, Sumit K; Ladak, Hanif M

2017-03-01

Finite-element models of the tympanic membrane are sensitive to the Young's modulus of the pars tensa. The aim of this work is to estimate the Young's modulus under a different experimental paradigm than currently used on the human tympanic membrane. These additional values could potentially be used by the auditory biomechanics community for building consensus. The Young's modulus of the human pars tensa was estimated through inverse finite-element modelling of an in-situ pressurization experiment. The experiments were performed on three specimens with a custom-built pressurization unit at a quasi-static pressure of 500 Pa. The shape of each tympanic membrane before and after pressurization was recorded using a Fourier transform profilometer. The samples were also imaged using micro-computed tomography to create sample-specific finite-element models. For each sample, the Young's modulus was then estimated by numerically optimizing its value in the finite-element model so simulated pressurized shapes matched experimental data. The estimated Young's modulus values were 2.2 MPa, 2.4 MPa and 2.0 MPa, and are similar to estimates obtained using in-situ single-point indentation testing. The estimates were obtained under the assumptions that the pars tensa is linearly elastic, uniform, isotropic with a thickness of 110 μm, and the estimates are limited to quasi-static loading. Estimates of pars tensa Young's modulus are sensitive to its thickness and inclusion of the manubrial fold. However, they do not appear to be sensitive to optimization initialization, height measurement error, pars flaccida Young's modulus, and tympanic membrane element type (shell versus solid). Copyright © 2017 Elsevier B.V. All rights reserved.

Identification of the first recurrent PAR1 deletion in Léri-Weill dyschondrosteosis and idiopathic short stature reveals the presence of a novel SHOX enhancer.

PubMed

Benito-Sanz, Sara; Royo, Jose Luis; Barroso, Eva; Paumard-Hernández, Beatriz; Barreda-Bonis, Ana C; Liu, Pengfei; Gracía, Ricardo; Lupski, James R; Campos-Barros, Ángel; Gómez-Skarmeta, José Luis; Heath, Karen Elise

2012-07-01

SHOX, located in the pseudoautosomal region 1 (PAR1) of the sexual chromosomes, encodes a transcription factor implicated in human growth. Defects in SHOX or its enhancers have been observed in ∼60% of Leri-Weill dyschondrosteosis (LWD) patients, a skeletal dysplasia characterised by short stature and/or the characteristic Madelung deformity, and in 2-5% of idiopathic short stature (ISS). To identify the molecular defect in the remaining genetically undiagnosed LWD and ISS patients, this study screened previously unanalysed PAR1 regions in 124 LWD and 576 ISS probands. PAR1 screening was undertaken by multiplex ligation dependent probe amplification (MLPA). Copy number alterations were subsequently confirmed and delimited by locus-specific custom-designed MLPA, array comparative genomic hybridisation (CGH) and breakpoint junction PCR/sequencing. A recurrent PAR1 deletion downstream of SHOX spanning 47543 bp with identical breakpoints was identified in 19 LWD (15.3%) and 11 ISS (1.9%) probands, from 30 unrelated families. Eight evolutionarily conserved regions (ECRs 1-8) identified within the deleted sequence were evaluated for SHOX regulatory activity by means of chromosome conformation capture (3C) in chicken embryo limbs and luciferase reporter assays in human U2OS osteosarcoma cells. The 3C assay indicated potential SHOX regulatory activity by ECR1, which was subsequently confirmed to act as a SHOX enhancer, operating in an orientation and position independent manner, in human U2OS cells. This study has identified the first recurrent PAR1 deletion in LWD and ISS, which results in the loss of a previously uncharacterised SHOX enhancer. The loss of this enhancer may decrease SHOX transcription, resulting in LWD or ISS due to SHOX haploinsufficiency.

Astragaloside Alleviates Hepatic Fibrosis Function via PAR2 Signaling Pathway in Diabetic Rats.

PubMed

Wang, Zhenchang; Li, Quanqiang; Xiang, Mingpeng; Zhang, Fengying; Wei, Dongyu; Wen, Zhixi; Zhou, Ying

2017-01-01

Astragaloside (AGS) extracted from radix astragalin (Huangqi) has been considered to be beneficial to liver diseases. In this study, we examined the role played by AGS in alleviating hepatic fibrosis function via protease-activated receptor-2 (PAR2) mechanisms. We hypothesized that AGS affects PAR2 signaling pathway thereby improving hepatic function in rats with hepatic fibrosis induced by carbon tetrachloride (CCl4). We further hypothesized that AGS attenuates impaired hepatic function evoked by CCl4 to a greater degree in diabetic animals. ELISA and Western Blot analysis were used to examine PAR2 signaling pathway in diabetic CCl4-rats and non-diabetic CCl4-rats. AGS inhibited the protein expression of PAR2 and its downstream pathway PKA and PKCɛ in CCl4-rats. Notably, the effects of AGS were greater in CCl4-rats with diabetes. AGS also significantly attenuated the CCl4-induced upregulations of pro-inflammatory cytokines, namely interleukin-1β, interleukin-6 and tumor necrosis factor-α accompanied with decreases of collagenic parameters such as hexadecenoic acid, laminin and hydroxyproline. Additionally, AGS improved the CCl4-induced exaggerations of liver index and functions including alanine aminotransferase, aspartate aminotransferase. Moreover, TGF-β1, a marker of hepatic fibrosis, was increased in CCl4-rats and AGS inhibited increases in TGF-β1 induced by CCl4. AGS alleviates hepatic fibrosis by inhibiting PAR2 signaling expression and its effects are largely enhanced in diabetic animals. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of hepatic fibrosis; and results of our study are likely to shed light on strategies for application of AGS because it has potentially greater therapeutic effectiveness for hepatic fibrosis in diabetes. © 2017 The Author(s)Published by S. Karger AG, Basel.

Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response: Water Available to Tropical Forest

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

Fang, Yilin; Leung, L. Ruby; Duan, Zhuoran

The Amazon basin experienced periodic droughts in the past, and climate models projected more intense and frequent droughts in the future. How tropical forests respond to drought may depend on water availability, which is modulated by landscape heterogeneity. Using the one-dimensional ACME Land Model (ALM) and the three-dimensional ParFlow variably saturated flow model, a series of numerical experiments were performed for the Asu catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoffmore » through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, the groundwater table is evidently deeper and the soil saturation is lower in the plateau compared to the valley. However, even in the plateau during the dry season in the drought year of 2005, plant transpiration is not water stressed in the ParFlow simulations as the soil saturation is still sufficient to maintain a soil matric potential for the stomata to be fully open. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation used in the models is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies.« less

Population attributable risk for chlamydia infection in a cohort of young international travellers (backpackers) and residents in Australia

PubMed Central

Guy, Rebecca; Donovan, Basil; McNulty, Anna

2011-01-01

Aim To estimate the population attributable risk (PAR) for Chlamydia trachomatis infection in young men and women in Sydney, Australia. Method Multivariate logistic regression was used to examine the association between demographic, sexual behaviour and other potential risk factors and chlamydia positivity in young (≤30 years) heterosexual international travellers (backpackers) and Australian residents attending a sexual health clinic. Point and interval estimates of PAR were calculated to quantify the proportion of chlamydia infections that can theoretically be prevented if a combination of risk factors is eliminated from a target population. Results In males, the PAR associated with inconsistent condom use in the past 3 months was 65% (95% CI 56% to 71%) in backpackers compared to 50% (95% CI 41% to 56%) in non-backpackers and the PAR associated with reporting three or more female sexual partners in the past 3 months was similar between male backpackers and non-backpackers (33% (95% CI 28% to 40%) and 36% (95% CI 32% to 41%), respectively). In females, the PAR associated with inconsistent condom use in the past 3 months was 51% (95% CI 42% to 59%) in backpackers compared to 41% (95% CI 31% to 51%) in non-backpackers, and the PAR associated with reporting three or more male sexual partners in the past 3 months was 14% (95% CI 11% to 18%) in backpackers compared to 30% (95% CI 25% to 37%) in non-backpackers. Conclusion These findings suggest that the largest number of chlamydia infections could be avoided by increasing condom use, particularly in backpackers. Reporting multiple partners was also associated with a large proportion of infections and the risk associated with this behaviour should be considered in health promotion strategies. PMID:22021720

Population attributable risk for chlamydia infection in a cohort of young international travellers (backpackers) and residents in Australia.

PubMed

Wand, Handan; Guy, Rebecca; Donovan, Basil; McNulty, Anna

2011-02-23

To estimate the population attributable risk (PAR) for Chlamydia trachomatis infection in young men and women in Sydney, Australia. Multivariate logistic regression was used to examine the association between demographic, sexual behaviour and other potential risk factors and chlamydia positivity in young (≤ 30 years) heterosexual international travellers (backpackers) and Australian residents attending a sexual health clinic. Point and interval estimates of PAR were calculated to quantify the proportion of chlamydia infections that can theoretically be prevented if a combination of risk factors is eliminated from a target population. In males, the PAR associated with inconsistent condom use in the past 3 months was 65% (95% CI 56% to 71%) in backpackers compared to 50% (95% CI 41% to 56%) in non-backpackers and the PAR associated with reporting three or more female sexual partners in the past 3 months was similar between male backpackers and non-backpackers (33% (95% CI 28% to 40%) and 36% (95% CI 32% to 41%), respectively). In females, the PAR associated with inconsistent condom use in the past 3 months was 51% (95% CI 42% to 59%) in backpackers compared to 41% (95% CI 31% to 51%) in non-backpackers, and the PAR associated with reporting three or more male sexual partners in the past 3 months was 14% (95% CI 11% to 18%) in backpackers compared to 30% (95% CI 25% to 37%) in non-backpackers. These findings suggest that the largest number of chlamydia infections could be avoided by increasing condom use, particularly in backpackers. Reporting multiple partners was also associated with a large proportion of infections and the risk associated with this behaviour should be considered in health promotion strategies.

Urokinase links plasminogen activation and cell adhesion by cleavage of the RGD motif in vitronectin.

PubMed

De Lorenzi, Valentina; Sarra Ferraris, Gian Maria; Madsen, Jeppe B; Lupia, Michela; Andreasen, Peter A; Sidenius, Nicolai

2016-07-01

Components of the plasminogen activation system including urokinase (uPA), its inhibitor (PAI-1) and its cell surface receptor (uPAR) have been implicated in a wide variety of biological processes related to tissue homoeostasis. Firstly, the binding of uPA to uPAR favours extracellular proteolysis by enhancing cell surface plasminogen activation. Secondly, it promotes cell adhesion and signalling through binding of the provisional matrix protein vitronectin. We now report that uPA and plasmin induces a potent negative feedback on cell adhesion through specific cleavage of the RGD motif in vitronectin. Cleavage of vitronectin by uPA displays a remarkable receptor dependence and requires concomitant binding of both uPA and vitronectin to uPAR Moreover, we show that PAI-1 counteracts the negative feedback and behaves as a proteolysis-triggered stabilizer of uPAR-mediated cell adhesion to vitronectin. These findings identify a novel and highly specific function for the plasminogen activation system in the regulation of cell adhesion to vitronectin. The cleavage of vitronectin by uPA and plasmin results in the release of N-terminal vitronectin fragments that can be detected in vivo, underscoring the potential physiological relevance of the process. © 2016 The Authors.

HAT1 induces lung cancer cell apoptosis via up regulating Fas.

PubMed

Han, Na; Shi, Lei; Guo, Qiuyun; Sun, Wei; Yu, Yang; Yang, Li; Zhang, Xiaoxi; Zhang, Mengxian

2017-10-27

The dysfunction of apoptosis is one of the factors contributing to lung cancer (LC) growth. Histone acetyltransferase HAT1 can up regulate cell apoptosis. This study aims to investigate the mechanism by which HAT1 induces LC cell (LCC) apoptosis via up regulating the expression of Fas. In this study, the surgically removed human LC tissues were collected. LCCs were isolated from the LC tissues and analyzed for the expression of HAT1 and Fas by RT-qPCR and Western blotting. We observed that the expression of Fas was negatively correlated with PAR2 in LCCs. Activation of PAR2 suppressed the expression of Fas in normal lung epithelial cells. The expression of HAT1 was lower and positively correlated with Fas expression and negatively correlated with PAR2 expression in LCCs. Activation of PAR2 suppressed Fas expression in lung epithelial cells via inhibiting HAT1. Restoration of HAT1 expression restored Fas expression in LCCs and induced LCC apoptosis. In conclusion, less expression of HAT1 in LCCs was associated with the pathogenesis of LC. Up regulation of HAT1 expression in LCCs can induce LCCs apoptosis, which may be a potential novel therapy for the treatment of LC.

The signaling adapter Gab1 regulates cell polarity by acting as a PAR protein scaffold

PubMed Central

Yang, Ziqiang; Xue, Bin; Umitsu, Masataka; Ikura, Mitsuhiko; Muthuswamy, Senthil K.; Neel, Benjamin G.

2012-01-01

Summary Cell polarity plays a key role in development and is disrupted in tumors, yet the molecules and mechanisms that regulate polarity remain poorly defined. We found that the scaffolding adaptor GAB1 interacts with two polarity proteins, PAR1 and PAR3. GAB1 binds PAR1 and enhances its kinase activity. GAB1 brings PAR1 and PAR3 into a transient complex, stimulating PAR3 phosphorylation by PAR1. GAB1 and PAR6 bind the PAR3 PDZ1 domain and thereby compete for PAR3 binding. Consequently, GAB1 depletion causes PAR3 hypo-phosphorylation and increases PAR3/PAR6 complex formation, resulting in accelerated and enhanced tight junction formation, increased trans-epithelial resistance and lateral domain shortening. Conversely, GAB1 over-expression, in a PAR1/PAR3-dependent manner, disrupts epithelial apical-basal polarity, promotes multi-lumen cyst formation, and enhances growth factor-induced epithelial cell scattering. Our results identify GAB1 as a novel negative regulator of epithelial cell polarity that functions as a scaffold for modulating PAR protein complexes on the lateral membrane. PMID:22883624

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system

NASA Astrophysics Data System (ADS)

Hu, Longhua; Vecchiarelli, Anthony G.; Mizuuchi, Kiyoshi; Neuman, Keir C.; Liu, Jian

The segregation of DNA prior to cell division is essential for faithful genetic inheritance. In many bacteria, segregation of the low-copy-number plasmids involves an active partition system composed of ParA ATPase and its stimulator protein ParB. Recent experiments suggest that ParA/ParB system motility is driven by a diffusion-ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. We develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB bound cargo. Paradoxically, the resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work sheds light on a new emergent phenomenon in which non-motor proteins work collectively via mechanochemical coupling to propel cargos -- an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

Solar radiation (PAR and UVA) and water temperature in relation to biochemical performance of Gelidium corneum (Gelidiales, Rhodophyta) in subtidal bottoms off the Basque coast

NASA Astrophysics Data System (ADS)

Quintano, Endika; Ganzedo, Unai; Díez, Isabel; Figueroa, Félix L.; Gorostiaga, José M.

2013-10-01

Gelidium corneum (Hudson) J.V. Lamouroux is a very important primary producer in the Cantabrian coastal ecosystem. Some local declines in their populations have been recently detected in the Basque coast. Occurrences of yellowing and an unusual branch breakdown pattern have also been reported for some G. corneum populations. In order to gain further insight into those environmental stressors operating at a local scale, here we investigate if shallow subtidal populations of G. corneum living under potentially different conditions of irradiance (PAR and UVA) and water temperature exhibit differences in some biochemical indicators of stress, namely C:N, antioxidant activity (radical cation of 2,2‧-azino-bis (3-ethylbenzothiazoline-6-sulfonate); ABTS+ assay) and mycosporine-like amino acids (MAAs) (Asterine 330 and Palythine). We hypothesised that G. corneum subjected to higher ambient levels of irradiance and water temperature would show higher C:N ratios, lower antioxidant activity and higher MAA concentrations. Our results partially support this hypothesis. We found that G. corneum exposed to increased levels of irradiance (PAR, UVA) exhibited greater C:N ratios and lower antioxidant activity (higher IC50), whereas no relationship was found regarding MAAs. No differences in biochemical performance in relation to temperature were detected among G. corneum exposed to comparable high light. Similarly, G. corneum growing under lower UVA radiation levels showed no differences in any of the measured biochemical variables with regard to PAR and water temperature. These findings suggest that, among the environmental factors examined, UVA radiation may be an important driver in regulating the along-shore variation in G. corneum biochemical performance. Therefore, the role of irradiance, especially UV radiation, in potential future alterations in Cantabrian G. corneum populations cannot be ruled out as a potential underlying factor.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system

PubMed Central

Hu, Longhua; Vecchiarelli, Anthony G.; Mizuuchi, Kiyoshi; Neuman, Keir C.; Liu, Jian

2015-01-01

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA–nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos—an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria. PMID:26647183

Canopy structural complexity predicts forest canopy light absorption at continental scales

NASA Astrophysics Data System (ADS)

Atkins, J. W.; Fahey, R. T.; Hardiman, B. S.; Gough, C. M.

2017-12-01

Understanding how the physical structure of forest canopies influence light acquisition is a long-standing area of inquiry fundamental to advancing understanding of many areas of the physical sciences, including the modeling and interpretation of biogeochemical cycles. Conventional measures of forest canopy structure employed in earth system models are often limited to leaf area index (LAI)—a measure of the quantity of leaves in the canopy. However, more novel multi-dimensional measures of canopy structural complexity (CSC) that describe the arrangement of vegetation are now possible because of technological advances, and may improve modeled estimates of canopy light absorption. During 2016 and 2017, we surveyed forests at sites from across the eastern, southern, and midwestern United States using portable canopy LiDAR (PCL). This survey included 14 National Ecological Observation Network (NEON), Long-Term Ecological Research Network (LTER,) Ameriflux, and University affiliated sites. Our findings show that a composite model including CSC parameters and LAI explains 96.8% of the variance in light acquisition, measured as the fraction of photosynthetically absorbed radiation (fPAR) at the continental scale, and improvement of 12% over an LAI only model. Under high light sky conditions, measures of CSC are more strongly coupled with light acquisition than under low light, possibly because light scattering partially decouples CSC from canopy light absorption under low, predominately diffuse light conditions. We conclude that scalable estimates of CSC metrics may improve continent-wide estimates of canopy light absorption and, therefore, carbon uptake, with implications for remote sensing and earth system modeling.

BOREAS TE-12 Incoming PAR Through the Forest Canopy Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Papagno, Andrea (Editor); Walter-Shea, Elizabeth A.; Mesarch, Mark A.

2000-01-01

The Boreal Ecosystem-Atmospheric Study (BOREAS) TE-12 (Terrestrial Ecology) team collected photosynthetically active radiation (PAR) data sets in support of its efforts to characterize and interpret information on shoot geometry, leaf optical properties, leaf water potential, and leaf gas exchange. The data were collected at the Southern Study Area-Old Black Spruce (SSA-OBS) site from 04-Jul-1996 to 25-Jul-1996. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

PARS: a web server for the prediction of Protein Allosteric and Regulatory Sites.

PubMed

Panjkovich, Alejandro; Daura, Xavier

2014-05-01

The regulation of protein activity is a key aspect of life at the molecular level. Unveiling its details is thus crucial to understanding signalling and metabolic pathways. The most common and powerful mechanism of protein-function regulation is allostery, which has been increasingly calling the attention of medicinal chemists due to its potential for the discovery of novel therapeutics. In this context, PARS is a simple and fast method that queries protein dynamics and structural conservation to identify pockets on a protein structure that may exert a regulatory effect on the binding of a small-molecule ligand.

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif

PubMed Central

Barillà, Daniela; Carmelo, Emma; Hayes, Finbarr

2007-01-01

The ParF protein of plasmid TP228 belongs to the ubiquitous superfamily of ParA ATPases that drive DNA segregation in bacteria. ATP-bound ParF polymerizes into multistranded filaments. The partner protein ParG is dimeric, consisting of C-termini that interweave into a ribbon–helix–helix domain contacting the centromeric DNA and unstructured N-termini. ParG stimulates ATP hydrolysis by ParF ≈30-fold. Here, we establish that the mobile tails of ParG are crucial for this enhancement and that arginine R19 within the tail is absolutely required for activation of ParF nucleotide hydrolysis. R19 is part of an arginine finger-like loop in ParG that is predicted to intercalate into the ParF nucleotide-binding pocket thereby promoting ATP hydrolysis. Significantly, mutations of R19 abrogated DNA segregation in vivo, proving that intracellular stimulation of ATP hydrolysis by ParG is a key regulatory process for partitioning. Furthermore, ParG bundles ParF-ATP filaments as well as promoting nucleotide-independent polymerization. The N-terminal flexible tail is required for both activities, because N-terminal ΔParG polypeptides are defective in both functions. Strikingly, the critical arginine finger-like residue R19 is dispensable for ParG-mediated remodeling of ParF polymers, revealing that the ParG N-terminal tail possesses two separable activities in the interplay with ParF: a catalytic function during ATP hydrolysis and a mechanical role in modulation of polymerization. We speculate that activation of nucleotide hydrolysis via an arginine finger loop may be a conserved, regulatory mechanism of ParA family members and their partner proteins, including ParA-ParB and Soj-Spo0J that mediate DNA segregation and MinD-MinE that determine septum localization. PMID:17261809

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif.

PubMed

Barillà, Daniela; Carmelo, Emma; Hayes, Finbarr

2007-02-06

The ParF protein of plasmid TP228 belongs to the ubiquitous superfamily of ParA ATPases that drive DNA segregation in bacteria. ATP-bound ParF polymerizes into multistranded filaments. The partner protein ParG is dimeric, consisting of C-termini that interweave into a ribbon-helix-helix domain contacting the centromeric DNA and unstructured N-termini. ParG stimulates ATP hydrolysis by ParF approximately 30-fold. Here, we establish that the mobile tails of ParG are crucial for this enhancement and that arginine R19 within the tail is absolutely required for activation of ParF nucleotide hydrolysis. R19 is part of an arginine finger-like loop in ParG that is predicted to intercalate into the ParF nucleotide-binding pocket thereby promoting ATP hydrolysis. Significantly, mutations of R19 abrogated DNA segregation in vivo, proving that intracellular stimulation of ATP hydrolysis by ParG is a key regulatory process for partitioning. Furthermore, ParG bundles ParF-ATP filaments as well as promoting nucleotide-independent polymerization. The N-terminal flexible tail is required for both activities, because N-terminal DeltaParG polypeptides are defective in both functions. Strikingly, the critical arginine finger-like residue R19 is dispensable for ParG-mediated remodeling of ParF polymers, revealing that the ParG N-terminal tail possesses two separable activities in the interplay with ParF: a catalytic function during ATP hydrolysis and a mechanical role in modulation of polymerization. We speculate that activation of nucleotide hydrolysis via an arginine finger loop may be a conserved, regulatory mechanism of ParA family members and their partner proteins, including ParA-ParB and Soj-Spo0J that mediate DNA segregation and MinD-MinE that determine septum localization.

Novel role for proteinase-activated receptor 2 (PAR2) in membrane trafficking of proteinase-activated receptor 4 (PAR4).

PubMed

Cunningham, Margaret R; McIntosh, Kathryn A; Pediani, John D; Robben, Joris; Cooke, Alexandra E; Nilsson, Mary; Gould, Gwyn W; Mundell, Stuart; Milligan, Graeme; Plevin, Robin

2012-05-11

Proteinase-activated receptors 4 (PAR(4)) is a class A G protein-coupled receptor (GPCR) recognized through the ability of serine proteases such as thrombin and trypsin to mediate receptor activation. Due to the irreversible nature of activation, a fresh supply of receptor is required to be mobilized to the cell surface for responsiveness to agonist to be sustained. Unlike other PAR subtypes, the mechanisms regulating receptor trafficking of PAR(4) remain unknown. Here, we report novel features of the intracellular trafficking of PAR(4) to the plasma membrane. PAR(4) was poorly expressed at the plasma membrane and largely retained in the endoplasmic reticulum (ER) in a complex with the COPI protein subunit β-COP1. Analysis of the PAR(4) protein sequence identified an arginine-based (RXR) ER retention sequence located within intracellular loop-2 (R(183)AR → A(183)AA), mutation of which allowed efficient membrane delivery of PAR(4). Interestingly, co-expression with PAR(2) facilitated plasma membrane delivery of PAR(4), an effect produced through disruption of β-COP1 binding and facilitation of interaction with the chaperone protein 14-3-3ζ. Intermolecular FRET studies confirmed heterodimerization between PAR(2) and PAR(4). PAR(2) also enhanced glycosylation of PAR(4) and activation of PAR(4) signaling. Our results identify a novel regulatory role for PAR(2) in the anterograde traffic of PAR(4). PAR(2) was shown to both facilitate and abrogate protein interactions with PAR(4), impacting upon receptor localization and cell signal transduction. This work is likely to impact markedly upon the understanding of the receptor pharmacology of PAR(4) in normal physiology and disease.

PAR proteins regulate maintenance-phase myosin dynamics during Caenorhabditis elegans zygote polarization

PubMed Central

Small, Lawrence E.; Dawes, Adriana T.

2017-01-01

Establishment of anterior–posterior polarity in the Caenorhabditis elegans zygote requires two different processes: mechanical activity of the actin–myosin cortex and biochemical activity of partitioning-defective (PAR) proteins. Here we analyze how PARs regulate the behavior of the cortical motor protein nonmuscle myosin (NMY-2) to complement recent efforts that investigate how PARs regulate the Rho GTPase CDC-42, which in turn regulates the actin-myosin cortex. We find that PAR-3 and PAR-6 concentrate CDC-42–dependent NMY-2 in the anterior cortex, whereas PAR-2 inhibits CDC-42–dependent NMY-2 in the posterior domain by inhibiting PAR-3 and PAR-6. In addition, we find that PAR-1 and PAR-3 are necessary for inhibiting movement of NMY-2 across the cortex. PAR-1 protects NMY-2 from being moved across the cortex by forces likely originating in the cytoplasm. Meanwhile, PAR-3 stabilizes NMY-2 against PAR-2 and PAR-6 dynamics on the cortex. We find that PAR signaling fulfills two roles: localizing NMY-2 to the anterior cortex and preventing displacement of the polarized cortical actin–myosin network. PMID:28615321

The effect of a periodic absorptive strip arrangement on an interior sound field in a room.

PubMed

Park, Joo-Bae; Grosh, Karl; Kim, Yang-Hann

2005-02-01

In this paper we study the effect of periodically arranged sound absorptive strips on the mean acoustic potential energy density distribution of a room. The strips are assumed to be attached on the room's surface of interest. In order to determine their effect, the mean acoustic potential energy density variation is evaluated as the function of a ratio of the strip's arrangement period to wavelength. The evaluation demonstrates that the mean acoustic potential energy density tends to converge. In addition, a comparison with a case in which absorptive materials completely cover the selected absorptive plane shows that a periodic arrangement that uses only half of the absorptive material can be more efficient than a total covering, unless the frequency of interest does not coincide with the room's resonant frequencies. Consequently, the results prove that the ratio of the arrangement period to the wavelength plays an important role in the effectiveness of a periodic absorptive strip arrangement to minimize a room's mean acoustic potential energy density.

Marine CDOM accumulation during a coastal Arctic mesocosm experiment: No response to elevated pCO2 levels

NASA Astrophysics Data System (ADS)

Pavlov, Alexey K.; Silyakova, Anna; Granskog, Mats A.; Bellerby, Richard G. J.; Engel, Anja; Schulz, Kai G.; Brussaard, Corina P. D.

2014-06-01

A large-scale multidisciplinary mesocosm experiment in an Arctic fjord (Kongsfjorden, Svalbard; 78°56.2'N) was used to study Arctic marine food webs and biogeochemical elements cycling at natural and elevated future carbon dioxide (CO2) levels. At the start of the experiment, marine-derived chromophoric dissolved organic matter (CDOM) dominated the CDOM pool. Thus, this experiment constituted a convenient case to study production of autochthonous CDOM, which is typically masked by high levels of CDOM of terrestrial origin in the Arctic Ocean proper. CDOM accumulated during the experiment in line with an increase in bacterial abundance; however, no response was observed to increased pCO2 levels. Changes in CDOM absorption spectral slopes indicate that bacteria were most likely responsible for the observed CDOM dynamics. Distinct absorption peaks (at 330 and 360 nm) were likely associated with mycosporine-like amino acids (MAAs). Due to the experimental setup, MAAs were produced in absence of ultraviolet exposure providing evidence for MAAs to be considered as multipurpose metabolites rather than simple photoprotective compounds. We showed that a small increase in CDOM during the experiment made it a major contributor to total absorption in a range of photosynthetically active radiation (PAR, 400-700 nm) and, therefore, is important for spectral light availability and may be important for photosynthesis and phytoplankton groups composition in a rapidly changing Arctic marine ecosystem.

Intrastrain heterogeneity of the mgpB gene in Mycoplasma genitalium is extensive in vitro and in vivo and suggests that variation is generated via recombination with repetitive chromosomal sequences.

PubMed

Iverson-Cabral, Stefanie L; Astete, Sabina G; Cohen, Craig R; Rocha, Eduardo P C; Totten, Patricia A

2006-07-01

Mycoplasma genitalium is associated with reproductive tract disease in women and may persist in the lower genital tract for months, potentially increasing the risk of upper tract infection and transmission to uninfected partners. Despite its exceptionally small genome (580 kb), approximately 4% is composed of repeated elements known as MgPar sequences (MgPa repeats) based on their homology to the mgpB gene that encodes the immunodominant MgPa adhesin protein. The presence of these MgPar sequences, as well as mgpB variability between M. genitalium strains, suggests that mgpB and MgPar sequences recombine to produce variant MgPa proteins. To examine the extent and generation of diversity within single strains of the organism, we examined mgpB variation within M. genitalium strain G-37 and observed sequence heterogeneity that could be explained by recombination between the mgpB expression site and putative donor MgPar sequences. Similarly, we analyzed mgpB sequences from cervical specimens from a persistently infected woman (21 months) and identified 17 different mgpB variants within a single infecting M. genitalium strain, confirming that mgpB heterogeneity occurs over the course of a natural infection. These observations support the hypothesis that recombination occurs between the mgpB gene and MgPar sequences and that the resulting antigenically distinct MgPa variants may contribute to immune evasion and persistence of infection.

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids

PubMed Central

Pillet, Flavien; Passot, Fanny Marie

2017-01-01

Bacterial centromeres–also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA—the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi) mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres. PMID:28562673

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

PubMed

Pillet, Flavien; Passot, Fanny Marie; Pasta, Franck; Anton Leberre, Véronique; Bouet, Jean-Yves

2017-01-01

Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi) mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

Spatial Heterogeneity of Ice Cover Sediment and Thickness and Its Effects on Photosynthetically Active Radiation and Chlorophyll-a Distribution: Lake Bonney, Antarctica

NASA Astrophysics Data System (ADS)

Obryk, M.; Doran, P. T.; Priscu, J. C.; Morgan-Kiss, R. M.; Siebenaler, A. G.

2012-12-01

The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica have been extensively studied under the Long Term Ecological Research project. But sampling has been spatially restricted due to the logistical difficulty of penetrating the 3-6 m of ice cover. The ice covers restrict wind-driven turbulence and its associated mixing of water, resulting in a unique thermal stratification and a strong vertical gradient of salinity. The permanent ice covers also shade the underlying water column, which, in turn, controls photosynthesis. Here, we present results of a three-dimensional record of lake processes obtained with an autonomous underwater vehicle (AUV). The AUV was deployed at West Lake Bonney, located in Taylor Valley, Dry Valleys, to further understand biogeochemical and physical properties of the Dry Valley lakes. The AUV was equipped with depth, conductivity, temperature, under water photosynthetically active radiation (PAR), turbidity, chlorophyll-and-DOM fluorescence, pH, and REDOX sensors. Measurements were taken over the course of two years in a 100 x 100 meter spaced horizontal sampling grid (and 0.2 m vertical resolution). In addition, the AUV measured ice thickness and collected 200 images looking up through the ice, which were used to quantify sediment distribution. Comparison with high-resolution satellite QuickBird imagery demonstrates a strong correlation between aerial sediment distribution and ice cover thickness. Our results are the first to show the spatial heterogeneity of lacustrine ecosystems in the McMurdo Dry Valleys, significantly improving our understanding of lake processes. Surface sediment is responsible for localized thinning of ice cover due to absorption of solar radiation, which in turn increases total available PAR in the water column. Higher PAR values are negatively correlated with chlorophyll-a, presenting a paradox; historically, long-term studies of PAR and chlorophyll-a have shown positive trends. We hypothesized that this paradox is a result of short-term photoadaptation of phytoplanktonic communities to spatial and temporal variations of PAR within the water column. To test this hypothesis, we established phytoplankton enrichment cultures from depths of maximum primary production (13 m) and tested whether dry valley lake phytoplankton respond to daily variations in controlled light environment. Laboratory-grown cultures exhibited a strong response at 12 hr:12 hr day:night cycle at the level of both photochemistry and chlorophyll biosynthesis, indicating that Lake Bonney possess the ability to quickly respond to changes in their light environment.

ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation

PubMed Central

Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta

2016-01-01

In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces. To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

Microtubules induce self-organization of polarized PAR domains in C. elegans zygotes

PubMed Central

Motegi, Fumio; Zonies, Seth; Hao, Yingsong; Cuenca, Adrian A.; Griffin, Erik; Seydoux, Geraldine

2011-01-01

A hallmark of polarized cells is the segregation of the PAR polarity regulators into asymmetric domains at the cell cortex1, 2. Antagonistic interactions involving two conserved kinases, atypical protein kinase C (aPKC) and PAR-1, have been implicated in polarity maintenance1, 2, but the mechanisms that initiate the formation of asymmetric PAR domains are not understood. Here, we describe one pathway used by the sperm-donated centrosome to polarize the PAR proteins in Caenorhabditis elegans zygotes. Before polarization, cortical aPKC excludes PAR-1 kinase and its binding partner PAR-2 by phosphorylation. During symmetry breaking, microtubules nucleated by the centrosome locally protect PAR-2 from phosphorylation by aPKC, allowing PAR-2 and PAR-1 to access the cortex nearest the centrosome. Cortical PAR-1 phosphorylates PAR-3, causing the PAR-3/aPKC complex to leave the cortex. Our findings illustrate how microtubules, independent of actin dynamics, stimulate the self-organization of PAR proteins by providing local protection against a global barrier imposed by aPKC. PMID:21983565

PAR-1 and PAR-2 Expression Is Enhanced in Inflamed Odontoblast Cells.

PubMed

Alvarez, M M P; Moura, G E; Machado, M F M; Viana, G M; de Souza Costa, C A; Tjäderhane, L; Nader, H B; Tersariol, I L S; Nascimento, F D

2017-12-01

Protease-activated receptors (PARs) are G protein-coupled receptors, which are activated by proteolytical cleavage of the amino-terminus and act as sensors for extracellular proteases. We hypothesized that PAR-1 and PAR-2 can be modulated by inflammatory stimulus in human dental pulp cells. PAR-1 and PAR-2 gene expression in human pulp tissue and MDPC-23 cells were analyzed by quantitative polymerase chain reaction. Monoclonal PAR-1 and PAR-2 antibodies were used to investigate the cellular expression of these receptors using Western blot, flow cytometry, and confocal microscopy in MDPC-23 cells. Immunofluorescence assays of human intact and carious teeth were performed to assess the presence of PAR-1 and PAR-2 in the dentin-pulp complex. The results show for the first time that human odontoblasts and MDPC-23 cells constitutively express PAR-1 and PAR-2. PAR-2 activation increased significantly the messenger RNA expression of matrix metalloproteinase (MMP)-2, MMP-9, MMP-13, and MMP-14 in MDPC-23 cells ( P < 0.05), while the expression of these enzymes decreased significantly in the PAR-1 agonist group ( P < 0.05). The high-performance liquid chromatography and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis showed the presence of MMP-13 activity cleaving PAR-1 at specific, noncanonical site TLDPRS 42 ↓F 43 LL in human dental pulp tissues. Also, we detected a presence of a trypsin-like activity cleaving PAR-2 at canonical site SKGR 20 ↓S 21 LIGRL in pulp tissues. Confocal microscopy analysis of human dentin-pulp complex showed intense positive staining of PAR-1 and PAR-2 in the odontoblast processes in dentinal tubules of carious teeth compared to intact ones. The present results support the hypothesis of activation of the upregulated PAR-1 and PAR-2 by endogenous proteases abundant during the inflammatory response in dentin-pulp complex.

Tunable multi-band absorption in metasurface of graphene ribbons based on composite structure

NASA Astrophysics Data System (ADS)

Ning, Renxia; Jiao, Zheng; Bao, Jie

2017-05-01

A tunable multiband absorption based on a graphene metasurface of composite structure at mid-infrared frequency was investigated by the finite difference time domain method. The composite structure were composed of graphene ribbons and a gold-MgF2 layer which was sandwiched in between two dielectric slabs. The permittivity of graphene is discussed with different chemical potential to obtain tunable absorption. And the absorption of the composite structure can be tuned by the chemical potential of graphene at certain frequencies. The impedance matching was used to study the perfect absorption of the structure in our paper. The results show that multi-band absorption can be obtained and some absorption peaks of the composite structure can be tuned through the changing not only of the width of graphene ribbons and gaps, but also the dielectric and the chemical potential of graphene. However, another peak was hardly changed by parameters due to a different resonant mechanism in proposed structure. This flexibily tunable multiband absorption may be applied to optical communications such as optical absorbers, mid infrared stealth devices and filters.

Absorption dynamics and delay time in complex potentials

NASA Astrophysics Data System (ADS)

Villavicencio, Jorge; Romo, Roberto; Hernández-Maldonado, Alberto

2018-05-01

The dynamics of absorption is analyzed by using an exactly solvable model that deals with an analytical solution to Schrödinger’s equation for cutoff initial plane waves incident on a complex absorbing potential. A dynamical absorption coefficient which allows us to explore the dynamical loss of particles from the transient to the stationary regime is derived. We find that the absorption process is characterized by the emission of a series of damped periodic pulses in time domain, associated with damped Rabi-type oscillations with a characteristic frequency, ω = (E + ε)/ℏ, where E is the energy of the incident waves and ‑ε is energy of the quasidiscrete state of the system induced by the absorptive part of the Hamiltonian; the width γ of this resonance governs the amplitude of the pulses. The resemblance of the time-dependent absorption coefficient with a real decay process is discussed, in particular the transition from exponential to nonexponential regimes, a well-known feature of quantum decay. We have also analyzed the effect of the absorptive part of the potential on the dynamical delay time, which behaves differently from the one observed in attractive real delta potentials, exhibiting two regimes: time advance and time delay.

Phosphorylation of Mycobacterium tuberculosis ParB Participates in Regulating the ParABS Chromosome Segregation System

PubMed Central

Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

2015-01-01

Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis. PMID:25807382

Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

PubMed

Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

2015-01-01

Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

Impacts of Light Use Efficiency and fPAR Parameterization on Gross Primary Production Modeling

NASA Technical Reports Server (NTRS)

Cheng, Yen-Ben; Zhang, Qingyuan; Lyapustin, Alexei I.; Wang, Yujie; Middleton, Elizabeth M.

2014-01-01

This study examines the impact of parameterization of two variables, light use efficiency (LUE) and the fraction of absorbed photosynthetically active radiation (fPAR or fAPAR), on gross primary production(GPP) modeling. Carbon sequestration by terrestrial plants is a key factor to a comprehensive under-standing of the carbon budget at global scale. In this context, accurate measurements and estimates of GPP will allow us to achieve improved carbon monitoring and to quantitatively assess impacts from cli-mate changes and human activities. Spaceborne remote sensing observations can provide a variety of land surface parameterizations for modeling photosynthetic activities at various spatial and temporal scales. This study utilizes a simple GPP model based on LUE concept and different land surface parameterizations to evaluate the model and monitor GPP. Two maize-soybean rotation fields in Nebraska, USA and the Bartlett Experimental Forest in New Hampshire, USA were selected for study. Tower-based eddy-covariance carbon exchange and PAR measurements were collected from the FLUXNET Synthesis Dataset. For the model parameterization, we utilized different values of LUE and the fPAR derived from various algorithms. We adapted the approach and parameters from the MODIS MOD17 Biome Properties Look-Up Table (BPLUT) to derive LUE. We also used a site-specific analytic approach with tower-based Net Ecosystem Exchange (NEE) and PAR to estimate maximum potential LUE (LUEmax) to derive LUE. For the fPAR parameter, the MODIS MOD15A2 fPAR product was used. We also utilized fAPAR chl, a parameter accounting for the fAPAR linked to the chlorophyll-containing canopy fraction. fAPAR chl was obtained by inversion of a radiative transfer model, which used the MODIS-based reflectances in bands 1-7 produced by Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm. fAPAR chl exhibited seasonal dynamics more similar with the flux tower based GPP than MOD15A2 fPAR, especially in the spring and fall at the agricultural sites. When using the MODIS MOD17-based parameters to estimate LUE, fAPAR chl generated better agreements with GPP (r2= 0.79-0.91) than MOD15A2 fPAR (r2= 0.57-0.84).However, underestimations of GPP were also observed, especially for the crop fields. When applying the site-specific LUE max value to estimate in situ LUE, the magnitude of estimated GPP was closer to in situ GPP; this method produced a slight overestimation for the MOD15A2 fPAR at the Bartlett forest. This study highlights the importance of accurate land surface parameterizations to achieve reliable carbon monitoring capabilities from remote sensing information.

Protease-activated receptor 2 (PAR2) is upregulated by Acanthamoeba plasminogen activator (aPA) and induces proinflammatory cytokine in human corneal epithelial cells.

PubMed

Tripathi, Trivendra; Abdi, Mahshid; Alizadeh, Hassan

2014-05-29

Acanthamoeba plasminogen activator (aPA) is a serine protease elaborated by Acanthamoeba trophozoites that facilitates the invasion of trophozoites to the host and contributes to the pathogenesis of Acanthamoeba keratitis (AK). The aim of this study was to explore if aPA stimulates proinflammatory cytokine in human corneal epithelial (HCE) cells via the protease-activated receptors (PARs) pathway. Acanthamoeba castellanii trophozoites were grown in peptone-yeast extract glucose for 7 days, and the supernatants were collected and centrifuged. The aPA was purified using the fast protein liquid chromatography system, and aPA activity was determined by zymography assays. Human corneal epithelial cells were incubated with or without aPA (100 μg/mL), PAR1 agonists (thrombin, 10 μM; TRAP-6, 10 μM), and PAR2 agonists (SLIGRL-NH2, 100 μM; AC 55541, 10 μM) for 24 and 48 hours. Inhibition of PAR1 and PAR2 involved preincubating the HCE cells for 1 hour with the antagonist of PAR1 (SCH 79797, 60 μM) and PAR2 (FSLLRY-NH2, 100 μM) with or without aPA. Human corneal epithelial cells also were preincubated with PAR1 and PAR2 antagonists and then incubated with or without PAR1 agonists (thrombin and TRAP-6) and PAR2 agonists (SLIGRL-NH2 and AC 55541). Expression of PAR1 and PAR2 was examined by quantitative RT-PCR (qRT-PCR), flow cytometry, and immunocytochemistry. Interleukin-8 expression was quantified by qRT-PCR and ELISA. Human corneal epithelial cells constitutively expressed PAR1 and PAR2 mRNA. Acanthamoeba plasminogen activator and PAR2 agonists significantly upregulated PAR2 mRNA expression (1- and 2-fold, respectively) (P < 0.05). Protease-activated receptor 2 antagonist significantly inhibited aPA, and PAR2 agonists induced PAR2 mRNA expression in HCE cells (P < 0.05). Protease-activated receptor 1 agonists, but not aPA, significantly upregulated PAR1 mRNA expression, which was significantly inhibited by PAR1 antagonist in HCE cells. Acanthamoeba plasminogen activator and PAR2 agonists stimulated IL-8 mRNA expression and protein production, which is significantly diminished by PAR2 antagonist (P < 0.05). Protease-activated receptor 1 antagonist did not alter aPA-stimulated IL-8 mRNA expression and protein production in HCE cells. Flow cytometry and immunocytochemistry showed that aPA and SLIGRL-NH2 (PAR2 agonist) upregulated PAR2 surface protein as compared to that in unstimulated HCE cells. Thrombin, but not aPA, stimulated PAR1 surface protein in HCE cells. Acanthamoeba plasminogen activator specifically induces expression and production of IL-8 in HCE cells via PAR2 pathway, and PAR2 antagonists may be used as a therapeutic target in AK. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

A New Class of Orthosteric uPAR•uPA Small-Molecule Antagonists Are Allosteric Inhibitors of the uPAR•Vitronectin Interaction

PubMed Central

Liu, Degang; Zhou, Donghui; Wang, Bo; Knabe, William Eric; Meroueh, Samy O.

2015-01-01

The urokinase receptor (uPAR) is a GPI-anchored cell surface receptor that is at the center of an intricate network of protein-protein interactions. Its immediate binding partners are the serine proteinase urokinase (uPA), and vitronectin (VTN), a component of the extracellular matrix. uPA and VTN bind at distinct sites on uPAR to promote extracellular matrix degradation and integrin signaling, respectively. Here, we report the discovery of a new class of pyrrolone small-molecule inhibitors of the tight ∼1 nM uPAR•uPA protein-protein interaction. These compounds were designed to bind to the uPA pocket on uPAR. The highest affinity compound, namely 7, displaced a fluorescently-labeled α-helical peptide (AE147-FAM) with an inhibition constant Ki of 0.7 µM and inhibited the tight uPAR•uPAATF interaction with an IC50 of 18 µM. Biophysical studies with surface plasmon resonance showed that VTN binding is highly dependent on uPA. This cooperative binding was confirmed as 7, which binds at the uPAR•uPA interface, also inhibited the distal VTN•uPAR interaction. In cell culture, 7 blocked the uPAR•uPA interaction in uPAR-expressing human embryonic kidney (HEK-293) cells, and impaired cell adhesion to VTN, a process that is mediated by integrins. As a result, 7 inhibited integrin signaling in MDA-MB-231 cancer cells as evidenced by a decrease in focal adhesion kinase (FAK) phosphorylation and Rac1 GTPase activation. Consistent with these results, 7 blocked breast MDA-MB-231 cancer cell invasion with IC50 values similar to those observed in ELISA and surface plasmon resonance competition studies. Explicit-solvent molecular dynamics simulations show that the cooperativity between uPA and VTN is attributed to stabilization of uPAR motion by uPA. In addition, free energy calculations revealed that uPA stabilizes the VTN•uPARSMB interaction through more favorable electrostatics and entropy. Disruption of the uPAR•VTNSMB interaction by 7 is consistent with the cooperative binding to uPAR by uPA and VTN. Interestingly, the VTNSMB•uPAR interaction was less favorable in the VTNSMB•uPAR•7 complex suggesting potential cooperativity between 7 and VTN. Compound 7 provides an excellent starting point for the development of more potent derivatives to explore uPAR biology. PMID:25671694

PH motifs in PAR1&2 endow breast cancer growth.

PubMed

Kancharla, A; Maoz, M; Jaber, M; Agranovich, D; Peretz, T; Grisaru-Granovsky, S; Uziely, B; Bar-Shavit, R

2015-11-24

Although emerging roles of protease-activated receptor1&2 (PAR1&2) in cancer are recognized, their underlying signalling events are poorly understood. Here we show signal-binding motifs in PAR1&2 that are critical for breast cancer growth. This occurs via the association of the pleckstrin homology (PH) domain with Akt/PKB as a key signalling event of PARs. Other PH-domain signal-proteins such as Etk/Bmx and Vav3 also associate with PAR1 and PAR2 through their PH domains. PAR1 and PAR2 bind with priority to Etk/Bmx. A point mutation in PAR2, H349A, but not in R352A, abrogates PH-protein association and is sufficient to markedly reduce PAR2-instigated breast tumour growth in vivo and placental extravillous trophoblast (EVT) invasion in vitro. Similarly, the PAR1 mutant hPar1-7A, which is unable to bind the PH domain, reduces mammary tumours and EVT invasion, endowing these motifs with physiological significance and underscoring the importance of these previously unknown PAR1 and PAR2 PH-domain-binding motifs in both pathological and physiological invasion processes.

Vibrational excitation in O2and Cl2inductively-coupled plasmas and DC discharges

NASA Astrophysics Data System (ADS)

Booth, Jean-Paul; Marinov, Daniil; Foucher, Mickael; Annusova, Adriana; Guerra, Vasco

2016-09-01

Low-energy electrons can interact with molecules via resonances to cause vibrational excitation with large cross-sections. Such processes can absorb significant energy from the plasma electrons, affecting the electron energy distribution and potentially (via vibration-translation (VT) energy transfer) causing substantial gas heating. The presence of vibrationally excited molecules may significant increase the rates of collisional processes, including electron dissociative attachment and electron impact dissociation into neutral atoms. However, the cross-sections of these processes are often poorly known since they are extremely difficult to measure directly, and reliable theoretical calculations are only now appearing for simple diatomic molecules. We have measured the vibrational distributions in discharges in pure O2 and pure Cl2, using high-sensitivity ultra-broadband ultraviolet absorption spectroscopy. In O2 plasmas significant vibrational excitation is observed, up to v'' =18, with a tail temperature of around 8000K. In Cl2 excitation is only observed up to v'' =3, and the distribution appears to be in local equilibrium with the gas translational temperature (up to 1500K). We are developing a detailed self-consistent 0D global model of these systems including vibrational excitation. Work performed in the LABEX Plas@par project, with financial state aid (ANR-11-IDEX-0004-02 and ANR-13-BS09-0019).

Proteinase-Activated Receptor-1 and Immunomodulatory Effects of a PAR1-Activating Peptide in a Mouse Model of Prostatitis

PubMed Central

Stanton, M. Mark; Nelson, Lisa K.; Benediktsson, Hallgrimur; Hollenberg, Morley D.; Buret, Andre G.; Ceri, Howard

2013-01-01

Background. Nonbacterial prostatitis has no established etiology. We hypothesized that proteinase-activated receptor-1 (PAR1) can play a role in prostatitis. We therefore investigated the effects of PAR1 stimulation in the context of a new model of murine nonbacterial prostatitis. Methods. Using a hapten (ethanol-dinitrobenzene sulfonic acid- (DNBS-)) induced prostatitis model with both wild-type and PAR1-null mice, we examined (1) the location of PAR1 in the mouse prostate and (2) the impact of a PAR1-activating peptide (TFLLR-NH2: PAR1-TF) on ethanol-DNBS-induced inflammation. Results. Ethanol-DNBS-induced inflammation was maximal at 2 days. In the tissue, PAR1 was expressed predominantly along the apical acini of prostatic epithelium. Although PAR1-TF on its own did not cause inflammation, its coadministration with ethanol-DNBS reduced all indices of acute prostatitis. Further, PAR1-TF administration doubled the prostatic production of interleukin-10 (IL-10) compared with ethanol-DNBS treatment alone. This enhanced IL-10 was not observed in PAR1-null mice and was not caused by the reverse-sequence receptor-inactive peptide, RLLFT-NH2. Surprisingly, PAR1-TF, also diminished ethanol-DNBS-induced inflammation in PAR1-null mice. Conclusions. PAR1 is expressed in the mouse prostate and its activation by PAR1-TF elicits immunomodulatory effects during ethanol-DNBS-induced prostatitis. However, PAR1-TF also diminishes ethanol-DNBS-induced inflammation via a non-PAR1 mechanism by activating an as-yet unknown receptor. PMID:24459330

Symmetry breaking and polarization of the C. elegans zygote by the polarity protein PAR-2.

PubMed

Zonies, Seth; Motegi, Fumio; Hao, Yingsong; Seydoux, Geraldine

2010-05-01

Polarization of the C. elegans zygote is initiated by ECT-2-dependent cortical flows, which mobilize the anterior PAR proteins (PAR-3, PAR-6 and PKC-3) away from the future posterior end of the embryo marked by the sperm centrosome. Here, we demonstrate the existence of a second, parallel and redundant pathway that can polarize the zygote in the absence of ECT-2-dependent cortical flows. This second pathway depends on the polarity protein PAR-2. We show that PAR-2 localizes to the cortex nearest the sperm centrosome even in the absence of cortical flows. Once on the cortex, PAR-2 antagonizes PAR-3-dependent recruitment of myosin, creating myosin flows that transport the anterior PAR complex away from PAR-2 in a positive-feedback loop. We propose that polarity in the C. elegans zygote is initiated by redundant ECT-2- and PAR-2-dependent mechanisms that lower PAR-3 levels locally, triggering a positive-feedback loop that polarizes the entire cortex.

Long-time dynamics through parallel trajectory splicing

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

Perez, Danny; Cubuk, Ekin D.; Waterland, Amos

2015-11-24

Simulating the atomistic evolution of materials over long time scales is a longstanding challenge, especially for complex systems where the distribution of barrier heights is very heterogeneous. Such systems are difficult to investigate using conventional long-time scale techniques, and the fact that they tend to remain trapped in small regions of configuration space for extended periods of time strongly limits the physical insights gained from short simulations. We introduce a novel simulation technique, Parallel Trajectory Splicing (ParSplice), that aims at addressing this problem through the timewise parallelization of long trajectories. The computational efficiency of ParSplice stems from a speculation strategymore » whereby predictions of the future evolution of the system are leveraged to increase the amount of work that can be concurrently performed at any one time, hence improving the scalability of the method. ParSplice is also able to accurately account for, and potentially reuse, a substantial fraction of the computational work invested in the simulation. We validate the method on a simple Ag surface system and demonstrate substantial increases in efficiency compared to previous methods. As a result, we then demonstrate the power of ParSplice through the study of topology changes in Ag 42Cu 13 core–shell nanoparticles.« less

New PARP targets for cancer therapy

PubMed Central

Vyas, Sejal; Chang, Paul

2015-01-01

Poly(ADP-ribose) polymerases (PARPs) modify target proteins post-translationally with poly(ADP-ribose) (PAR) or mono(ADP-ribose) (MAR) using NAD+ as substrate. The best-studied PARPs generate PAR modifications and include PARP1 and the tankyrase PARP5a, both of which are targets for cancer therapy with inhibitors in either clinical trials or preclinical development. There are 15 additional PARPs, the majority of which modify proteins with MAR, and their biology is less well understood. Recent data identify potentially cancer relevant functions for these PARPs, indicating that we need to understand more about these PARPs in order to target them effectively. PMID:24898058

Role of the parCBA Operon of the Broad-Host-Range Plasmid RK2 in Stable Plasmid Maintenance

PubMed Central

Easter, Carla L.; Schwab, Helmut; Helinski, Donald R.

1998-01-01

The par region of the stably maintained broad-host-range plasmid RK2 is organized as two divergent operons, parCBA and parDE, and a cis-acting site. parDE encodes a postsegregational killing system, and parCBA encodes a resolvase (ParA), a nuclease (ParB), and a protein of unknown function (ParC). The present study was undertaken to further delineate the role of the parCBA region in the stable maintenance of RK2 by first introducing precise deletions in the three genes and then assessing the abilities of the different constructs to stabilize RK2 in three strains of Escherichia coli and two strains of Pseudomonas aeruginosa. The intact parCBA operon was effective in stabilizing a conjugation-defective RK2 derivative in E. coli MC1061K and RR1 but was relatively ineffective in E. coli MV10Δlac. In the two strains in which the parCBA operon was effective, deletions in parB, parC, or both parB and parC caused an approximately twofold reduction in the stabilizing ability of the operon, while a deletion in the parA gene resulted in a much greater loss of parCBA activity. For P. aeruginosa PAO1161Rifr, the parCBA operon provided little if any plasmid stability, but for P. aeruginosa PAC452Rifr, the RK2 plasmid was stabilized to a substantial extent by parCBA. With this latter strain, parA and res alone were sufficient for stabilization. The cer resolvase system of plasmid ColE1 and the loxP/Cre system of plasmid P1 were tested in comparison with the parCBA operon. We found that, not unlike what was previously observed with MC1061K, cer failed to stabilize the RK2 plasmid with par deletions in strain MV10Δlac, but this multimer resolution system was effective in stabilizing the plasmid in strain RR1. The loxP/Cre system, on the other hand, was very effective in stabilizing the plasmid in all three E. coli strains. These observations indicate that the parA gene, along with its res site, exhibits a significant level of plasmid stabilization in the absence of the parC and parB genes but that in at least one E. coli strain, all three genes are required for maximum stabilization. It cannot be determined from these results whether or not the stabilization effects seen with parCBA or the cer and loxP/Cre systems are strictly due to a reduction in the level of RK2 dimers and an increase in the number of plasmid monomer units or if these systems play a role in a more complex process of plasmid stabilization that requires as an essential step the resolution of plasmid dimers. PMID:9811663

A peptide inhibitor of the urokinase/urokinase receptor system inhibits alteration of the blood-retinal barrier in diabetes.

PubMed

Navaratna, Deepti; Menicucci, Gina; Maestas, Joann; Srinivasan, Ramprasad; McGuire, Paul; Das, Arup

2008-09-01

One of the major complications of diabetes is the alteration of the blood-retinal barrier, leading to retinal edema and consequent vision loss. The aim of this study was to evaluate the role of the urokinase plasminogen activator (uPA)/uPA receptor (uPAR) system in the regulation of retinal vascular permeability. Biochemical, molecular, and histological techniques were used to examine the role of uPA and uPAR in the regulation of retinal vascular permeability in diabetic rats and cultured retinal endothelial cells. The increased retinal vascular permeability in diabetic rats was associated with a decrease in vascular endothelial (VE) -cadherin expression in retinal vessels. Treatment with the uPA/uPAR-inhibiting peptide (A6) was shown to reduce diabetes-induced permeability and the loss of VE-cadherin. The increased permeability of cultured cells in response to advanced glycation end products (AGEs) was significantly inhibited with A6. Treatment of endothelial cells with specific matrix metalloproteinases or AGEs resulted in loss of VE-cadherin from the cell surface, which could be inhibited by A6. uPA/uPAR physically interacts with AGEs/receptor for advanced glycation end products on the cell surface and regulates its activity. uPA and its receptor uPAR play important roles in the alteration of the blood-retinal barrier through proteolytic degradation of VE-cadherin. The ability of A6 to block retinal vascular permeability in diabetes suggests a potential therapeutic approach for the treatment of diabetic macular edema.

Comparisons of luminaires: Efficacies and system design

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

Albright, L.D.; Both, A.J.

1994-12-31

After reviewing basic information, three design examples have been presented to demonstrate a process of supplemental lighting design. The sequences of each example suggest careful thought and analysis are required to obtain supplemental lighting designs that provide both high levels of PAR and suitable uniformity. The end results should suggest how an analysis can evolve to achieve desired results, and the types of tools and adjustments required. It appears possible to design research greenhouses and plant growth chambers to achieve a {+-}10% PAR uniformity using HIPS luminaires. Further, HPS luminaires (and, by extension, NEHD, etc.) are required to achieve highmore » PAR levels and have the decided advantage of providing the possibility of aiming, which reduces the region of the {open_quotes}edge effect{close_quotes}. Further, for designing plant lighting systems, a modification of the standard IES luminaire data file structure is potentially useful. Luminaire installation is an important factor to obtain PAR uniformity. Spacing and mounting height are critically important. Additionally, the mounting angle of each luminaire must be carefully adjusted to conform with design assumptions. This is true for both plant growth chambers and greenhouses. Surface reflectances are particularly important when designing for small lighted regions such as plant growth chambers and research greenhouses. It is not obvious, just from looking at a surface, what its reflectance is. It is suggested that an effort be mounted to develop valid surface reflectance data to be used by designers. The importance of the surfaces (particularly the walls) in achieving PAR uniformity suggests the importance of periodic cleaning/maintenance to retain initial reflectance values.« less

Etudes optiques de nouveaux materiaux laser: Des orthosilicates dopes a l'ytterbium: Le yttrium (lutetium,scandium) pentoxide de silicium

NASA Astrophysics Data System (ADS)

Denoyer, Aurelie

La decouverte et l'elaboration de nouveaux materiaux laser solides suscitent beaucoup d'interet parmi la communaute scientifique. En particulier les lasers dans la gamme de frequence du micron debouchent sur beaucoup d'applications, en telecommunication, en medecine, dans le domaine militaire, pour la, decoupe des metaux (lasers de puissance), en optique non lineaire (doublage de frequence, bistabilite optique). Le plus couramment utilise actuellement est le Nd:YAG dans cette famille de laser, mais des remplacants plus performants sont toujours recherches. Les lasers a base d'Yb3+ possedent beaucoup d'avantages compares aux lasers Nd3+ du fait de leur structure electronique simple et de leur deterioration moins rapide. Parmi les matrices cristallines pouvant accueillir l'ytterbium, les orthosilicates Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5 se positionnent tres bien, du fait de leur bonne conductivite thermique et du fort eclatement de leur champ cristallin necessaire a l'elaboration de lasers quasi-3 niveaux. De plus l'etude fine et systematique des proprietes microscopiques de nouveaux materiaux s'avere toujours tres interessante du point de vue de la recherche fondamentale, c'est ainsi que de nouveaux modeles sont concus (par exemple pour le champ cristallin) ou que de nouvelles proprietes inhabituelles sont decouvertes, menant a de nouvelles applications. Ainsi d'autres materiaux dopes a l'ytterbium sont connus pour leurs proprietes de couplage electron-phonon, de couplage magnetique, d'emission cooperative ou encore de bistabilite optique, mais ces proprietes n'ont encore jamais ete mises en evidence dans Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5. Ainsi, cette these a pour but l'etude des proprietes optiques et des interactions microscopiques dans Yb:Y2SiO 5, Yb:Lu2SiO5 et Yb:Sc2SiO5. Nous utilisons principalement les techniques d'absorption IR et de spectroscopie Raman pour determiner les excitations du champ cristallin et les modes de vibration dans le materiau. Des mesures optiques sous champ magnetique ont egalement ete effectuees dans le but de caracteriser le comportement de ces excitations lorsqu'elles sont soumises a l'effet Zeeman. La resonance paramagnetique electronique a permis de completer cette etude de l'eclatement Zeeman suivant toutes les orientations du cristal. Enfin la fluorescence par excitation selective et la fluorescence induite par Raman FT, completent la description des niveaux d'energie et revelent l'existence d'emission cooperative de deux ions Yb3+ et de transferts d'energie. Les resultats de cette these apportent une contribution originale dans le domaine des nouveaux materiaux lasers par l'etude et la comprehension des interactions fines et des proprietes microscopiques d'un materiau en particulier. Ils debouchent a la fois sur des applications possibles dans le domaine de l'optique et des lasers, et sur la comprehension d'aspects fondamentaux. Cette these a prouve l'interet de ces matrices pour leur utilisation comme lasers solides: un fort eclatement du champ cristallin favorable a l'elaboration de laser quasi-3 niveaux, et de larges bandes d'absorption (dues a un fort couplage electron-phonon et a des raies satellites causees par une interaction d'echange entre deux ions Yb3+) qui permettent la generation d'impulsions laser ultra-courtes, l'accordabilite du laser, etc. De plus la miniaturisation des lasers est possible pour l'optique integree grace a des couches minces synthetisees par epitaxie en phase liquide dont nous avons demontre la tres bonne qualite structurale et l'ajustement possible de certains parametres. Nous avons reconstruit le tenseur g du niveau fondamental (qui donne des informations precieuses sur les fonctions d'onde), ceci dans le but d'aider les theoriciens a concevoir un modele de champ cristallin valide. Plusieurs mecanismes de transferts d'energie ont ete mis en evidence: un mecanisme de relaxation d'un site vers l'autre, un mecanisme d'emission cooperative, et un mecanisme d'excitation de l'Yb3+ par le Tm3+ (impurete presente dans le materiau). Ces transferts sont plutot nefastes pour la fabrication d'un laser mais sont interessants pour l'optique non lineaire (doublage de frequence, memoires optiques). Enfin, plusieurs elements (le couplage magnetique de paire, le couplage electron-phonon et l'emission cooperative) nous ont permis de conclure sur le caractere covalent de la matrice. Nous avons d'ailleurs demontre ici le role de la covalence dans l'emission cooperative, transition habituellement attribuee aux interactions multipolaires electriques.

The role of protease-activated receptors PAR-1 and PAR-2 in the repair of 16HBE 14o(-) epithelial cell monolayers in vitro.

PubMed

Ewen, D; Clarke, S L; Smith, J R; Berger, C; Salmon, G; Trevethick, M; Shute, J K

2010-03-01

We recently reported that repair following mechanical wounding of epithelial cell layers in vitro is dependent on fibrin formation and the activity of locally expressed coagulation cascade proteins. Serine proteases of the coagulation cascade are an important group of protease-activated receptor (PAR) activators and PAR-1 to 4 are expressed by the normal bronchial epithelium. We tested the hypothesis that activation of PAR-1 and PAR-2 by coagulation cascade proteases stimulates epithelial repair via effects on fibrin formation. Using mechanically wounded 16HBE 14o(-) epithelial cell layers in culture, we investigated the effect of PAR-1 and PAR-2 agonist peptides, control partially scrambled peptides and PAR-neutralizing antibodies on the rate of repair and fibrin formation. Coagulation factors in culture supernatants were measured by immunoblot. RT-PCR was used to investigate PAR-1, PAR-2 and PGE2 receptor (EP-1 to EP-4) expression in this model and qRT-PCR to quantify responses to wounding. Additionally, we investigated the effect of exogenously added factor Xa (FXa) and neutrophil elastase and the influence of PGE2 and indomethacin on the repair response. PAR-1 and PAR-2 peptide agonists stimulated the rate of repair and enhanced the formation of a fibrin provisional matrix to support the repair process. Conversely, PAR-neutralizing antibodies inhibited repair. Under serum-free culture conditions, 16HBE 14o(-) cells expressed EP-2 and EP-3, but not EP-1 or EP-4, receptors. Wounding induced an increased expression of EP-3 but did not alter EP-2, PAR-1 or PAR-2 expression. In the absence of PAR agonists, there was no evidence for a role for PGE2 in fibrin formation or the repair process. Indomethacin attenuated fibrin formation in wounded cultures only in the presence of the PAR-2 peptide. FXa stimulated epithelial repair while neutrophil elastase reduced the levels of coagulation factors and inhibited repair. Locally expressed serine proteases of the coagulation cascade activate PAR-1 and PAR-2 to enhance fibrin formation and bronchial epithelial repair.

Loss of Par-1a/MARK3/C-TAK1 kinase leads to reduced adiposity, resistance to hepatic steatosis, and defective gluconeogenesis.

PubMed

Lennerz, Jochen K; Hurov, Jonathan B; White, Lynn S; Lewandowski, Katherine T; Prior, Julie L; Planer, G James; Gereau, Robert W; Piwnica-Worms, David; Schmidt, Robert E; Piwnica-Worms, Helen

2010-11-01

Par-1 is an evolutionarily conserved protein kinase required for polarity in worms, flies, frogs, and mammals. The mammalian Par-1 family consists of four members. Knockout studies of mice implicate Par-1b/MARK2/EMK in regulating fertility, immune homeostasis, learning, and memory as well as adiposity, insulin hypersensitivity, and glucose metabolism. Here, we report phenotypes of mice null for a second family member (Par-1a/MARK3/C-TAK1) that exhibit increased energy expenditure, reduced adiposity with unaltered glucose handling, and normal insulin sensitivity. Knockout mice were protected against high-fat diet-induced obesity and displayed attenuated weight gain, complete resistance to hepatic steatosis, and improved glucose handling with decreased insulin secretion. Overnight starvation led to complete hepatic glycogen depletion, associated hypoketotic hypoglycemia, increased hepatocellular autophagy, and increased glycogen synthase levels in Par-1a(-/-) but not in control or Par-1b(-/-) mice. The intercrossing of Par-1a(-/-) with Par-1b(-/-) mice revealed that at least one of the four alleles is necessary for embryonic survival. The severity of phenotypes followed a rank order, whereby the loss of one Par-1b allele in Par-1a(-/-) mice conveyed milder phenotypes than the loss of one Par-1a allele in Par-1b(-/-) mice. Thus, although Par-1a and Par-1b can compensate for one another during embryogenesis, their individual disruption gives rise to distinct metabolic phenotypes in adult mice.

Elevated fecal peptidase D at onset of colitis in Galphai2-/- mice, a mouse model of IBD.

PubMed

Bergemalm, Daniel; Kruse, Robert; Sapnara, Maria; Halfvarson, Jonas; Hörnquist, Elisabeth Hultgren

2017-01-01

The identification of novel fecal biomarkers in inflammatory bowel disease (IBD) is hampered by the complexity of the human fecal proteome. On the other hand, in experimental mouse models there is probably less variation. We investigated the fecal protein content in mice to identify possible biomarkers and pathogenic mechanisms. Fecal samples were collected at onset of inflammation in Galphai2-/- mice, a well-described spontaneous model of chronic colitis, and from healthy littermates. The fecal proteome was analyzed by two-dimensional electrophoresis and quantitative mass spectrometry and results were then validated in a new cohort of mice. As a potential top marker of disease, peptidase D was found at a higher ratio in Galphai2-/- mouse feces relative to controls (fold change 27; p = 0.019). Other proteins found to be enriched in Gαi2-/- mice were mainly pancreatic proteases, and proteins from plasma and blood cells. A tendency of increased calprotectin, subunit S100-A8, was also observed (fold change 21; p = 0.058). Proteases are potential activators of inflammation in the gastrointestinal tract through their interaction with the proteinase-activated receptor 2 (PAR2). Accordingly, the level of PAR2 was found to be elevated in both the colon and the pancreas of Galphai2-/- mice at different stages of disease. These findings identify peptidase D, an ubiquitously expressed intracellular peptidase, as a potential novel marker of colitis. The elevated levels of fecal proteases may be involved in the pathogenesis of colitis and contribute to the clinical phenotype, possibly by activation of intestinal PAR2.

Testing UK blood donors for exposure to human parvovirus 4 using a time-resolved fluorescence immunoassay to screen sera and Western blot to confirm reactive samples.

PubMed

Maple, Peter A C; Beard, Stuart; Parry, Ruth P; Brown, Kevin E

2013-10-01

Human parvovirus 4 (ParV4), a newly described member of the family Parvoviridae, like B19V, has been found in pooled plasma preparations. The extent, and significance, of ParV4 exposure in UK blood donors remain to be determined and reliable detection of ParV4 immunoglobulin (Ig)G, using validated methods, is needed. With ParV4 virus-like particles a ParV4 IgG time-resolved fluorescence immunoassay (TRFIA) was developed. There is no gold standard or reference assay for measuring ParV4 IgG and the utility of the TRFIA was first examined using a panel of sera from people who inject drugs (PWIDS)--a high-prevalence population for ParV4 infection. Western blotting was used to confirm the specificity of TRFIA-reactive sera. Two cohorts of UK blood donor sera comprising 452 sera collected in 1999 and 156 sera collected in 2009 were tested for ParV4 IgG. Additional testing for B19V IgG, hepatitis C virus antibodies (anti-HCV), and ParV4 DNA was also undertaken. The rate of ParV4 IgG seroprevalence in PWIDS was 20.7% and ParV4 IgG was positively associated with the presence of anti-HCV with 68.4% ParV4 IgG-positive sera testing anti-HCV-positive versus 17.1% ParV4 IgG-negative sera. Overall seropositivity for ParV4 IgG, in 608 UK blood donors was 4.76%. The ParV4 IgG seropositivity for sera collected in 1999 was 5.08%, compared to 3.84% for sera collected in 2009. No ParV4 IgG-positive blood donor sera had detectable ParV4 DNA. ParV4 IgG has been found in UK blood donors and this finding needs further investigation. © 2013 American Association of Blood Banks.

Milestone Report:3.2.2.26 Appliances, HVAC & Water Heating R&D-Select Sorption Technology

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

Ally, Moonis Raza

The purpose of this report is to select a sorption technology based on recent work completed on characterizing working pairs for both absorption and adsorption technologies based on Global Warming Potential (GWP) of less than 100 (relative to carbon dioxide, 100-year atmospheric life span) and zero Ozone Depletion Potential (ODP). From a total of eighty-three potential working pairs (absorption technology), there were only two candidate working pairs for the absorption technology, and 8 potential working pairs for adsorption technology. After screening these ten potential candidates on the basis of sizes of the desorber, absorber/adsorber, evaporator, condenser, and rectifier (where applicable),more » the ORNL-Georgia Tech study concluded that best working pairs are NH3-H2O for the most compact system in terms of heat transfer equipment surface area, and NH3-LiNO3 and MeOH-[mmin][DMP] where efficiency is most important. Based on a single-stage absorption and adsorption modeling using the Engineering Equation Solver (EES), the performance of both sorption systems was evaluated from known heat transfer correlations, and thermos-physical properties. Based on these results, the technology chosen is absorption technology. The selected technology is absorption for the reasons cited in Section 4.« less

PAR-2 regulates dental pulp inflammation associated with caries.

PubMed

Lundy, F T; About, I; Curtis, T M; McGahon, M K; Linden, G J; Irwin, C R; El Karim, I A

2010-07-01

Protease-activated receptors (PARs) are G-protein-coupled receptors that are activated enzymatically by proteolysis of an N-terminal domain. The cleavage and activation of PARs by serine proteases represent a novel mechanism by which such enzymes could influence the host inflammatory response. The aim of this study was to determine whether PAR-2 expression and activation were increased in dental caries. Using immunohistochemistry, we showed PAR-2 to be localized to pulp cells subjacent to caries lesions, but minimally expressed by healthy pulp tissue. Trypsin and the PAR-2 agonist (PAR2-AP) activated PAR-2 in an in vitro functional assay. Endogenous molecules present in pulp cell lysates from carious teeth specifically activated PAR-2, but those from healthy teeth failed to do so. The activation of PAR-2 in vitro was shown to increase the expression of the pro-inflammatory mediator cyclo-oxygenase-2 (COX-2), providing a mechanism whereby PAR-2 could modulate pulpal inflammation.

Protease-Activated Receptor-2 Activation Contributes to House Dust Mite-Induced IgE Responses in Mice

PubMed Central

Post, Sijranke; Heijink, Irene H.; Petersen, Arjen H.; de Bruin, Harold G.; van Oosterhout, Antoon J. M.; Nawijn, Martijn C.

2014-01-01

Aeroallergens such as house dust mite (HDM), cockroach, and grass or tree pollen are innocuous substances that can induce allergic sensitization upon inhalation. The serine proteases present in these allergens are thought to activate the protease-activated receptor (PAR)-2, on the airway epithelium, thereby potentially inducing allergic sensitization at the expense of inhalation tolerance. We hypothesized that the proteolytic activity of allergens may play an important factor in the allergenicity to house dust mite and is essential to overcome airway tolerance. Here, we aimed to investigate the role of PAR-2 activation in allergic sensitization and HDM-induced allergic airway inflammation. In our study, Par-2 deficient mice were treated with two different HDM extracts containing high and low serine protease activities twice a week for a period of 5 weeks. We determined airway inflammation through quantification of percentages of mononuclear cells, eosinophils and neutrophils in the bronchial alveolar lavage fluid and measured total IgE and HDM-specific IgE and IgG1 levels in serum. Furthermore, Th2 and pro-inflammatory cytokines including IL-5, IL-13, Eotaxin-1, IL-17, KC, Chemokine (C-C motif) ligand 17 (CCL17) and thymic stromal lymphopoietin (TSLP), were measured in lung tissue homogenates. We observed that independent of the serine protease content, HDM was able to induce elevated levels of eosinophils and neutrophils in the airways of both wild-type (WT) and Par-2 deficient mice. Furthermore, we show that induction of pro-inflammatory cytokines by HDM exposure is independent of Par-2 activation. In contrast, serine protease activity of HDM does contribute to enhanced levels of total IgE, but not HDM-specific IgE. We conclude that, while Par-2 activation contributes to the development of IgE responses, it is largely dispensable for the HDM-induced induction of pro-inflammatory cytokines and airway inflammation in an experimental mouse model of HDM-driven allergic airway disease. PMID:24651123

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

Makarewicz, Jan, E-mail: jama@amu.edu.pl; Shirkov, Leonid

The pyridine-Ar (PAr) van der Waals (vdW) complex is studied using a high level ab initio method. Its structure, binding energy, and intermolecular vibrational states are determined from the analytical potential energy surface constructed from interaction energy (IE) values computed at the coupled cluster level of theory with single, double, and perturbatively included triple excitations with the augmented correlation consistent polarized valence double-ζ (aug-cc-pVDZ) basis set complemented by midbond functions. The structure of the complex at its global minimum with Ar at a distance of 3.509 Å from the pyridine plane and shifted by 0.218 Å from the center ofmore » mass towards nitrogen agrees well with the corresponding equilibrium structure derived previously from the rotational spectrum of PAr. The PAr binding energy D{sub e} of 392 cm{sup −1} is close to that of 387 cm{sup −1} calculated earlier at the same ab initio level for the prototypical benzene-Ar (BAr) complex. However, under an extension of the basis set, D{sub e} for PAr becomes slightly lower than D{sub e} for BAr. The ab initio vdW vibrational energy levels allow us to estimate the reliability of the methods for the determination of the vdW fundamentals from the rotational spectra. To disclose the character of the intermolecular interaction in PAr, the symmetry-adapted perturbation theory (SAPT) is employed for the analysis of different physical contributions to IE. It is found that SAPT components of IE can be approximately expressed in the binding region by only two of them: the exchange repulsion and dispersion energy. The total induction effect is negligible. The interrelations between various SAPT components found for PAr are fulfilled for a few other complexes involving aromatic molecules and Ar or Ne, which indicates that they are valid for all rare gas (Rg) atoms and aromatics.« less

Study on Light Interception and Biomass Production of Different Cotton Cultivars

PubMed Central

Mao, Shuchun; Han, Yingchun; Feng, Lu; Wang, Guoping; Yang, Beifang; Zhi, Xiaoyu; Fan, Zhengyi; Lei, Yaping; Du, Wenli; Li, Yabing

2016-01-01

Identifying the characteristics of light interception and utilization is of great significance for improving the potential photosynthetic activity of plants. The present research investigates the differences in absorbing and converting photosynthetically active radiation (PAR) among various cotton cultivars. Field experiments were conducted in 2012, 2013 and 2014 in Anyang, Henan, China. Ten cultivars with different maturity and plant architectures were planted at a density of 60,000 plants ha-1 in randomized blocks, with three replicates. The spatial distribution of light in canopy was measured and quantified with a geo-statistical method, according to which the cumulative amount of intercepted radiation was calculated by Simpson 3/8 rules. Finally, light interception was analyzed in association with the biomass accumulation of different cultivars. The key results were: (1) late-maturing varieties with an incompact plant architecture captured more solar radiation throughout the whole growth period than middle varieties with columnar architecture and even more than early varieties with compact architecture, and they produced more biomass; (2) the highest PAR interception ratio and the maximum biomass accumulation rate occurred during the blossoming and boll-forming stage, when leaf area index (LAI) reached its peak; (3) the distribution within the canopy presented a significant spatial heterogeneity, and at late growing stage, the PAR was mainly intercepted by upper canopies in incompact-type plant communities, but was more homogeneous in columnar-type plants; however, the majority of radiation was transmitted through the canopy in compact-type colonies; (4) there was not a consistent variation relationship between the cumulative intercepted PAR (iPAR) and biomass among these cultivars over the three years of the study. Based on these results, we attempted to clarify the distinction in light spatial distribution within different canopies and the patterns of PAR interception in diverse cotton cultivars with different hereditary characters, thereby providing a significant basis for researchers to select cultivars with appropriate growth period and optimal plant architecture for improvement of light interception and utilization. PMID:27227675

Effect and mechanism of PAR-2 on the proliferation of esophageal cancer cells.

PubMed

Quanjun, D; Qingyu, Z; Qiliang, Z; Liqun, X; Jinmei, C; Ziquan, L; Shike, H

2016-11-01

Esophageal Cancer (EC) is a common malignant tumor occurred in the digestive tract. In this study, we investigated the mechanism of Protease Activated Receptor 2 (PAR-2) on the proliferation of esophageal cancer cell. Transfected esophageal cancer (EC) cell (PAR-2shRNA EC109) was established with low stable PAR-2 expression. EC109 cell was treated with PAR-2 agonist, PAR-2 anti-agonist and MAPK inhibitor respectively; Untreated EC109 cell (blank control) and PAR-2shRNA EC109 cell were used for analysis also. The mRNA expressions of PAR-2, ERK1, Cyclin D1, and c-fos in each group were detected by reverse transcript and polymerase chain reaction. Western blot was used to detect the protein expressions in each group. The cell growth curves were drawn to compare the cell growth. Compared with the blank control, the mRNA and protein expressions of PAR-2, Cyclin D1, and c-fos in PAR-2 agonist group increased significantly (p < 0.05), while decreased significantly in PAR-2shRNA EC109 cell and MAPK inhibitor group (p < 0.05). The mRNA expression of ERK1 and protein expression of p-ERK1 increased in PAR-2 agonist group, decreased in PAR-2shRNA EC109 cell and MAPK inhibitor group when compared with blank control (p < 0.05). The growth of cells was upward in PAR-2 agonist group at cell growth phase when compared with blank control, while decreased in PAR-2 shRNA EC109 cell and MAPK inhibitor group with statistical difference (p < 0.05). PAR-2 regulate cell proliferation through the MAPK pathway in esophageal carcinoma cell, and Cyclin D1, c-fos are involved in this process.

Protease-activated Receptor-4 Signaling and Trafficking Is Regulated by the Clathrin Adaptor Protein Complex-2 Independent of β-Arrestins*

PubMed Central

Smith, Thomas H.; Coronel, Luisa J.; Li, Julia G.; Dores, Michael R.; Nieman, Marvin T.; Trejo, JoAnn

2016-01-01

Protease-activated receptor-4 (PAR4) is a G protein-coupled receptor (GPCR) for thrombin and is proteolytically activated, similar to the prototypical PAR1. Due to the irreversible activation of PAR1, receptor trafficking is intimately linked to signal regulation. However, unlike PAR1, the mechanisms that control PAR4 trafficking are not known. Here, we sought to define the mechanisms that control PAR4 trafficking and signaling. In HeLa cells depleted of clathrin by siRNA, activated PAR4 failed to internalize. Consistent with clathrin-mediated endocytosis, expression of a dynamin dominant-negative K44A mutant also blocked activated PAR4 internalization. However, unlike most GPCRs, PAR4 internalization occurred independently of β-arrestins and the receptor's C-tail domain. Rather, we discovered a highly conserved tyrosine-based motif in the third intracellular loop of PAR4 and found that the clathrin adaptor protein complex-2 (AP-2) is important for internalization. Depletion of AP-2 inhibited PAR4 internalization induced by agonist. In addition, mutation of the critical residues of the tyrosine-based motif disrupted agonist-induced PAR4 internalization. Using Dami megakaryocytic cells, we confirmed that AP-2 is required for agonist-induced internalization of endogenous PAR4. Moreover, inhibition of activated PAR4 internalization enhanced ERK1/2 signaling, whereas Akt signaling was markedly diminished. These findings indicate that activated PAR4 internalization requires AP-2 and a tyrosine-based motif and occurs independent of β-arrestins, unlike most classical GPCRs. Moreover, these findings are the first to show that internalization of activated PAR4 is linked to proper ERK1/2 and Akt activation. PMID:27402844

Proteinase-activated receptors (PARs) – focus on receptor-receptor-interactions and their physiological and pathophysiological impact

PubMed Central

2013-01-01

Proteinase-activated receptors (PARs) are a subfamily of G protein-coupled receptors (GPCRs) with four members, PAR1, PAR2, PAR3 and PAR4, playing critical functions in hemostasis, thrombosis, embryonic development, wound healing, inflammation and cancer progression. PARs are characterized by a unique activation mechanism involving receptor cleavage by different proteinases at specific sites within the extracellular amino-terminus and the exposure of amino-terminal “tethered ligand“ domains that bind to and activate the cleaved receptors. After activation, the PAR family members are able to stimulate complex intracellular signalling networks via classical G protein-mediated pathways and beta-arrestin signalling. In addition, different receptor crosstalk mechanisms critically contribute to a high diversity of PAR signal transduction and receptor-trafficking processes that result in multiple physiological effects. In this review, we summarize current information about PAR-initiated physical and functional receptor interactions and their physiological and pathological roles. We focus especially on PAR homo- and heterodimerization, transactivation of receptor tyrosine kinases (RTKs) and receptor serine/threonine kinases (RSTKs), communication with other GPCRs, toll-like receptors and NOD-like receptors, ion channel receptors, and on PAR association with cargo receptors. In addition, we discuss the suitability of these receptor interaction mechanisms as targets for modulating PAR signalling in disease. PMID:24215724

The 14-3-3 Protein PAR-5 Regulates the Asymmetric localization of the LET-99 Spindle Positioning Protein

PubMed Central

Rose, Lesilee S.

2016-01-01

PAR proteins play important roles in establishing cytoplasmic polarity as well as regulating spindle positioning during asymmetric division. However, the molecular mechanisms by which the PAR proteins generate asymmetry in different cell types are still being elucidated. Previous studies in C. elegans revealed that PAR-3 and PAR-1 regulate the asymmetric localization of LET-99, which in turn controls spindle positioning by affecting the distribution of the conserved force generating complex. In wild-type embryos, LET-99 is localized in a lateral cortical band pattern, via inhibition at the anterior by PAR-3 and at the posterior by PAR-1. In this report, we show that the 14-3-3 protein PAR-5 is also required for cortical LET-99 asymmetry. PAR-5 associated with LET-99 in pull-down assays, and two PAR-5 binding sites were identified in LET-99 using the yeast two-hybrid assay. Mutation of these sites abolished binding in yeast and altered LET-99 localization in vivo: LET-99 was present at the highest levels at the posterior pole of the embryo instead of a band in par-5 embryos. Together the results indicate that PAR-5 acts in a mechanism with PAR-1 to regulate LET-99 cortical localization. PMID:26921457

Observation and estimation of photosynthetically active radiation in Lhasa (Tibetan Plateau)

NASA Astrophysics Data System (ADS)

Peng, Simao; Du, Qingyun; Lin, Aiwen; Hu, Bo; Xiao, Ke; Xi, Yuliang

2015-03-01

In this study, we measured photosynthetically active radiation (PAR) and global solar radiation (G) in Lhasa, located on the Tibetan Plateau, from 2006 to 2012 to examine the PAR and PAR/G (PAR fraction) seasonal characteristics. The maximum and minimum values of both PAR and the PAR fraction occurred in summer and winter, respectively. Moreover, the PAR and PAR fraction annual averages were 38.64 mol m-2 d-1 and 1.84 mol M J-1, respectively. An efficient all-weather model used for estimating PAR under various sky conditions was developed based on the relationships among PAR, the cosine of the solar zenith angle and the clearness index in Lhasa. The model also produced acceptable estimations of PAR with high accuracy at the Donghu and Sanjiang weather stations. A PAR dataset was reconstructed from G using the newly developed model for the period 1961-2012. The modelled annual mean daily PAR was approximately 37.62 mol m-2 d-1. A significant decreasing trend (-0.61 mol m-2 per decade) over the last 50 years was observed on the Tibetan Plateau; this decrease was largest in autumn (-1.024 mol m-2 per decade), and relatively small decreases were observed in summer. The results also revealed that PAR began increasing at 0.164 mol m-2 per year from 1991 to 2012, which was inconsistent with the variations of G. The proposed all-weather PAR model could be useful for ecological modelling and agricultural processes in the Tibetan Plateau region of China.

Loss of Par-1a/MARK3/C-TAK1 Kinase Leads to Reduced Adiposity, Resistance to Hepatic Steatosis, and Defective Gluconeogenesis ▿

PubMed Central

Lennerz, Jochen K.; Hurov, Jonathan B.; White, Lynn S.; Lewandowski, Katherine T.; Prior, Julie L.; Planer, G. James; Gereau, Robert W.; Piwnica-Worms, David; Schmidt, Robert E.; Piwnica-Worms, Helen

2010-01-01

Par-1 is an evolutionarily conserved protein kinase required for polarity in worms, flies, frogs, and mammals. The mammalian Par-1 family consists of four members. Knockout studies of mice implicate Par-1b/MARK2/EMK in regulating fertility, immune homeostasis, learning, and memory as well as adiposity, insulin hypersensitivity, and glucose metabolism. Here, we report phenotypes of mice null for a second family member (Par-1a/MARK3/C-TAK1) that exhibit increased energy expenditure, reduced adiposity with unaltered glucose handling, and normal insulin sensitivity. Knockout mice were protected against high-fat diet-induced obesity and displayed attenuated weight gain, complete resistance to hepatic steatosis, and improved glucose handling with decreased insulin secretion. Overnight starvation led to complete hepatic glycogen depletion, associated hypoketotic hypoglycemia, increased hepatocellular autophagy, and increased glycogen synthase levels in Par-1a−/− but not in control or Par-1b−/− mice. The intercrossing of Par-1a−/− with Par-1b−/− mice revealed that at least one of the four alleles is necessary for embryonic survival. The severity of phenotypes followed a rank order, whereby the loss of one Par-1b allele in Par-1a−/− mice conveyed milder phenotypes than the loss of one Par-1a allele in Par-1b−/− mice. Thus, although Par-1a and Par-1b can compensate for one another during embryogenesis, their individual disruption gives rise to distinct metabolic phenotypes in adult mice. PMID:20733003

An Estimate of Attributable Cases of Alzheimer Disease and Vascular Dementia due to Modifiable Risk Factors: The Impact of Primary Prevention in Europe and in Italy.

PubMed

Mayer, Flavia; Di Pucchio, Alessandra; Lacorte, Eleonora; Bacigalupo, Ilaria; Marzolini, Fabrizio; Ferrante, Gianluigi; Minardi, Valentina; Masocco, Maria; Canevelli, Marco; Di Fiandra, Teresa; Vanacore, Nicola

2018-01-01

Up to 53.7% of all cases of dementia are assumed to be due to Alzheimer disease (AD), while 15.8% are considered to be due to vascular dementia (VaD). In Europe, about 3 million cases of AD could be due to 7 potentially modifiable risk factors: diabetes, midlife hypertension and/or obesity, physical inactivity, depression, smoking, and low educational level. To estimate the number of VaD cases in Europe and the number of AD and VaD cases in Italy attributable to these 7 potentially modifiable risk factors. Assuming the nonindependence of the 7 risk factors, the adjusted combined population attributable risk (PAR) was estimated for AD and VaD. In Europe, adjusted combined PAR was 31.4% for AD and 37.8% for VaD. The total number of attributable cases was 3,033,000 for AD and 873,000 for VaD. In Italy, assuming a 20% reduction of the prevalence of each risk factor, adjusted combined PAR decreased from 45.2 to 38.9% for AD and from 53.1 to 46.6% for VaD, implying a 6.4 and 6.5% reduction in the prevalence of AD and VaD, respectively. A relevant reduction of AD and VaD cases in Europe and Italy could be obtained through primary prevention.

Architecture of the ParF*ParG protein complex involved in prokaryotic DNA segregation.

PubMed

Barillà, Daniela; Hayes, Finbarr

2003-07-01

The mechanism by which low copy number plasmids are segregated at cell division involves the concerted action of two plasmid-encoded proteins that assemble on a centromere-like site. This study explores the topology of the DNA segregation machinery specified by the parFG locus of TP228, a partition system which is phylogenetically distinct from more well-characterized archetypes. A variety of genetic, biochemical and biophysical strategies revealed that the ParG protein is dimeric. ParF, which is more closely related to the cell division regulator MinD than to the prototypical ParA partition protein of plasmid P1, is instead multimeric and its polymeric state appears to be modulated by ATP which correlates with the proposed ATP-binding activity of ParF. ParG interacts in a sequence-specific manner with the DNA region upstream of the parFG locus and this binding is modulated by ParF. Intriguingly, the ParF and ParG proteins form at least two types of discrete complex in the absence of this region suggesting that the assembly dynamics of these proteins onto DNA is intricate.

Optical and physical properties of stratospheric aerosols from balloon measurements in the visible and near-infrared domains. I. Analysis of aerosol extinction spectra from the AMON and SALOMON balloonborne spectrometers

NASA Astrophysics Data System (ADS)

Berthet, Gwenaël; Renard, Jean-Baptiste; Brogniez, Colette; Robert, Claude; Chartier, Michel; Pirre, Michel

2002-12-01

Aerosol extinction coefficients have been derived in the 375-700-nm spectral domain from measurements in the stratosphere since 1992, at night, at mid- and high latitudes from 15 to 40 km, by two balloonborne spectrometers, Absorption par les Minoritaires Ozone et NOx (AMON) and Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON). Log-normal size distributions associated with the Mie-computed extinction spectra that best fit the measurements permit calculation of integrated properties of the distributions. Although measured extinction spectra that correspond to background aerosols can be reproduced by the Mie scattering model by use of monomodal log-normal size distributions, each flight reveals some large discrepancies between measurement and theory at several altitudes. The agreement between measured and Mie-calculated extinction spectra is significantly improved by use of bimodal log-normal distributions. Nevertheless, neither monomodal nor bimodal distributions permit correct reproduction of some of the measured extinction shapes, especially for the 26 February 1997 AMON flight, which exhibited spectral behavior attributed to particles from a polar stratospheric cloud event.

Controlling enhanced absorption in graphene metamaterial

NASA Astrophysics Data System (ADS)

Zhou, Qihui; Liu, Peiguo; Bian, Li-an; Liu, Hanqing; Liu, Chenxi; Chen, Genghui

2018-04-01

In this paper, a controllable terahertz (THz) metamaterial absorber (MA) is designed with the circuit analog method. Taking advantage of the patterned graphene on SiO2/doped Si/polyimide substrates with a gold reflector, the controllable MA achieves perfect absorption at 0.75 THz. The chemical potential of graphene is regulated by controlling the voltage between graphene and doped Si layers. As the chemical potential varies from 0 eV to 0.5 eV, the MA is changed from reflection (<0.37) to absorption (>0.99). The distributions of surface current and electric field are illustrated to analyze the resonant characteristic of patterned graphene. According to the resonant characteristic, we introduce patterned graphene elements with different dimension in a unit cell, which effectively extends the effective absorption bandwidth (absorption > 0 . 9) from 0.67-0.93 THz to 0.52-0.95 THz. Moreover, replacing part of the graphene structure with gold, the switchable MA is turned into a frequency tunable MA. The absorption peak moves from 0.62 THz to 0.92 THz as the chemical potential increases from 0.1 eV to 0.5 eV. These designs overcome limitation of traditional absorbers and exhibit great potentials in many practical applications.

PAR-2 triggers placenta-derived protease-induced altered VE-cadherin reorganization at endothelial junctions in preeclampsia.

PubMed

Gu, Y; Groome, L J; Alexander, J S; Wang, Y

2012-10-01

PAR-2 is a G-protein coupled protease receptor whose activation in endothelial cells (ECs) is associated with increased solute permeability. VE-cadherin is an endothelial-specific junction protein, which exhibits a disorganized distribution at cell junction during inflammation and is a useful indicator of endothelial barrier dysfunction. In the present study, we tested the hypothesis that PAR-2 activation mediates placenta-derived chymotrypsin-like protease (CLP)-induced endothelial junction disturbance and permeability in preeclampsia (PE). PAR-2 and VE-cadherin were examined by immunofluorescent staining. Specific CLP induced PAR-2 activation and altered VE-cadherin distribution was assessed following depletion of protease chymotrypsin in the placental conditioned medium and after PAR-2 siRNA. VE-cadherin assembly was determined by treating cells with protease chymotrypsin and/or the specific PAR-2 agonist SLIGKV-NH2. Our results showed: 1) placental conditioned medium not only disturbed VE-cadherin distribution at cell junctions but also activated PAR-2 in ECs; 2) PAR-2 siRNA blocked the placental conditioned medium induced PAR-2 upregulation and disorganization of VE-cadherin at cell junctions; 3) PAR-2 agonist induced PAR-2 activation and VE-cadherin reorganization were dose-dependent; and 4) PAR-2 agonist could stimulate ERK1/2 activation. These results strongly suggest that proteases produced by the placenta elicit endothelial barrier dysfunction via a PAR-2 signaling regulatory mechanism in PE. Copyright © 2012 Elsevier Ltd. All rights reserved.

Protease Activated Receptor-2 Mediates Activated Protein C–Induced Cutaneous Wound Healing via Inhibition of p38

PubMed Central

Julovi, Sohel M.; Xue, Meilang; Dervish, Suat; Sambrook, Philip N.; March, Lyn; Jackson, Christopher John

2011-01-01

Activated protein C (APC) is a natural anticoagulant that exerts anti-inflammatory and cytoprotective properties mediated through the protease activated receptor (PAR)-1. APC can also proteolytically cleave PAR-2, although subsequent function is unknown. On the basis of recent evidence that APC promotes wound healing, the aim of this study was to determine whether APC acts through PARs to heal murine excisional wounds or to regulate human cultured keratinocyte function and to determine the signaling mechanisms. Topical administration of APC accelerated wound healing in wild-type mice and, unexpectedly, in PAR-1 knockout mice. PAR-2 knockout mice healed significantly slower than wild-type mice, and healing was not altered by adding APC, indicating that APC acts through PAR-2 to heal wounds. In cultured human primary keratinocytes, APC enhanced PAR-2, stimulated proliferation, activated phosphatidylinositol 3-kinase/Src/Akt, and inhibited phosphorylated (P)-p38. Inhibiting PAR-1 or PAR-2, by small-interfering RNA or blocking antibody, reversed APC-induced keratinocyte proliferation and Akt activation. Blocking PAR-2, but not PAR-1, reversed the inhibition of P-p38 by APC. Furthermore, inhibition of P-p38 accelerated wound healing in wild-type mice. In summary, although APC acts through both PAR-1 and PAR-2 to activate Akt and to increase keratinocyte proliferation, APC-induced murine wound healing depends on PAR-2 activity and inhibition of P-p38. PMID:21907694

PAR-2 triggers placenta-derived protease-induced altered VE-cadherin reorganization at endothelial junctions in preeclampsia

PubMed Central

Gu, Yang; Groome, Lynn J.; Alexander, J. Steven; Wang, Yuping

2014-01-01

PAR-2 is a G-protein coupled protease receptor whose activation in endothelial cells (ECs) is associated with increased solute permeability. VE-cadherin is an endothelial specific junction protein, which exhibits a disorganized distribution at cell junction during inflammation and is a useful indicator of endothelial barrier dysfunction. In the present study, we tested the hypothesis that PAR-2 activation mediates placenta-derived chymotrypsin-like protease (CLP)-induced endothelial junction disturbance and permeability in preeclampsia (PE). PAR-2 and VE-cadherin were examined by immunofluorescent staining. Specific CLP-induced PAR-2 activation and altered VE-cadherin distribution was assessed following depletion of protease chymotrypsin in the placental conditioned medium and after PAR-2 siRNA. VE-cadherin assembly was determined by treating cells with protease chymotrypsin and/or the specific PAR-2 agonist SLIGKV-NH2. Our results showed: 1) placental conditioned medium not only disturbed VE-cadherin distribution at cell junctions but also activated PAR-2 in ECs; 2) PAR-2 siRNA blocked the placental conditioned medium induced PAR-2 upregulation and disorganization of VE-cadherin at cell junctions; 3) PAR-2 agonist induced PAR-2 activation and VE-cadherin reorganization were dose-dependent; and 4) PAR-2 agonist could stimulate ERK1/2 activation. These results strongly suggest that proteases produced by the placenta elicit endothelial barrier dysfunction via a PAR-2 signaling regulatory mechanism in PE. PMID:22840244

The difference in endolymphatic hydrostatic pressure elevation induced by isoproterenol between the ampulla and the cochlea.

PubMed

Inamoto, Ryuhei; Miyashita, Takenori; Matsubara, Ai; Hoshikawa, Hiroshi; Mori, Nozomu

2017-06-01

The purpose of the study was to investigate the difference in the responses of endolymphatic hydrostatic pressure to isoproterenol, β-adrenergic receptor agonist, between pars superior and pars inferior. The hydrostatic pressure of endolymph and perilymph and endolymphatic potential in the ampulla and the cochlea during the intravenous administration of isoproterenol were recorded using a servo-null system in guinea pigs. The hydrostatic pressure of endolymph and perilymph in the ampulla and cochlea was similar in magnitude. Isoproterenol significantly increased hydrostatic pressure of ampullar and cochlear endolymph and perilymph with no change in the ampullar endolymphatic potential and endocochlear potential, respectively. The isoproterenol-induced maximum change of endolymphatic hydrostatic pressure in ampulla was significantly (p<0.01) smaller than that in the cochlea. In ears with an obstructed endolymphatic sac, the action of isoproterenol on endolymphatic hydrostatic pressure in the ampulla disappeared like that in the cochlea. Isoproterenol elevates endolymphatic hydrostatic pressure in different manner between the vestibule and the cochlea. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

An ELISA method detecting the active form of suPAR.

PubMed

Zhou, Xiaolei; Xu, Mingming; Huang, Hailong; Mazar, Andrew; Iqbal, Zafar; Yuan, Cai; Huang, Mingdong

2016-11-01

Urokinase plasminogen activator receptor (uPAR) exists in a number of formats in human plasma, including soluble uPAR (suPAR) and uPAR fragments. We developed an ELISA method to detect specifically the active form suPAR, which binds to its natural ligand uPA. The intra CV and inter CV of this ELISA assay is 8.5% and 9.6% respectively, and the assay can recover 99.74% of added recombinant suPAR from 10% plasma. This assay is quite sensitive, capable of detecting down to 15pg/ml of suPAR, and can measure suPAR concentrations in the range of 0.031-8ng/ml with high linear relationship. Plasma samples from pregnant women were also measured for the active form of suPAR with this assay, giving an averaged level of 1.39ng/ml, slightly higher than the level of pooled plasma from healthy donors (0.96ng/ml). This study demonstrates the feasibility to measure the active form of suPAR, which will likely have value in clinical applications. Copyright © 2016. Published by Elsevier B.V.

The 14-3-3 protein PAR-5 regulates the asymmetric localization of the LET-99 spindle positioning protein.

PubMed

Wu, Jui-Ching; Espiritu, Eugenel B; Rose, Lesilee S

2016-04-15

PAR proteins play important roles in establishing cytoplasmic polarity as well as regulating spindle positioning during asymmetric division. However, the molecular mechanisms by which the PAR proteins generate asymmetry in different cell types are still being elucidated. Previous studies in Caenorhabditis elegans revealed that PAR-3 and PAR-1 regulate the asymmetric localization of LET-99, which in turn controls spindle positioning by affecting the distribution of the conserved force generating complex. In wild-type embryos, LET-99 is localized in a lateral cortical band pattern, via inhibition at the anterior by PAR-3 and at the posterior by PAR-1. In this report, we show that the 14-3-3 protein PAR-5 is also required for cortical LET-99 asymmetry. PAR-5 associated with LET-99 in pull-down assays, and two PAR-5 binding sites were identified in LET-99 using the yeast two-hybrid assay. Mutation of these sites abolished binding in yeast and altered LET-99 localization in vivo: LET-99 was present at the highest levels at the posterior pole of the embryo instead of a band in par-5 embryos. Together the results indicate that PAR-5 acts in a mechanism with PAR-1 to regulate LET-99 cortical localization. Copyright © 2016 Elsevier Inc. All rights reserved.

Tissue Factor-Factor VIIa Complex Triggers Protease Activated Receptor 2-Dependent Growth Factor Release and Migration in Ovarian Cancer

PubMed Central

Chanakira, Alice; Westmark, Pamela R.; Ong, Irene M.; Sheehan, John P.

2017-01-01

Objective Enhanced tissue factor (TF) expression in epithelial ovarian cancer (EOC) is associated with aggressive disease. Our objective was to evaluate the role of the TF-factor VIIa-protease-activated receptor-2 (PAR-2) pathway in human EOC. Methods TCGA RNAseq data from EOC databases were analyzed for PAR expression. Cell and microparticle (MP) associated TF protein expression (Western blot) and MP-associated coagulant activity were determined in human EOC (SKOV-3, OVCAR-3 and CaOV-3) and control cell lines. PAR-1 and PAR-2 protein expression were similarly examined. The PAR dependence of VEGF-A release (ELISA) and chemotactic migration in response to FVIIa and cellular proliferation in response to thrombin was evaluated with small molecule antagonists. Results Relative mRNA expression consistently demonstrated PAR-2>PAR-1≫PAR-3/4 in multiple EOC datasets. Human EOC cell line lysates confirmed expression of TF, PAR-1 and PAR-2 proteins. MPs isolated from EOC cell lines demonstrated markedly enhanced (4–10 fold) TF coagulant activity relative to control cell lines. FVIIa induced a dose-dependent increase in VEGF-A release (2.5-3 fold) from EOC cell lines that was abrogated by the PAR-2 antagonist ENMD-1068. FVIIa treatment of CaOV-3 and OVCAR-3 cells resulted in increased chemotactic migration that was abolished by ENMD-1068. Thrombin induced dose-dependent EOC cell line proliferation was completely reversed by the PAR-1 antagonist vorapaxar. Small molecule antagonists had no effect on these phenotypes without protease present. Conclusions Enhanced activity of the TF-FVIIa-PAR-2 axis may contribute to the EOC progression via PAR-2 dependent signaling that supports an angiogenic and invasive phenotype and local thrombin generation supporting PAR-1 dependent proliferation. PMID:28148395

Proteinase-activated receptor 2 modulates OA-related pain, cartilage and bone pathology

PubMed Central

Huesa, Carmen; Ortiz, Ana C; Dunning, Lynette; McGavin, Laura; Bennett, Louise; McIntosh, Kathryn; Crilly, Anne; Kurowska-Stolarska, Mariola; Plevin, Robin; van ‘t Hof, Rob J; Rowan, Andrew D; McInnes, Iain B; Goodyear, Carl S; Lockhart, John C; Ferrell, William R

2016-01-01

Objective Proteinase-activated receptor 2 (PAR2) deficiency protects against cartilage degradation in experimental osteoarthritis (OA). The wider impact of this pathway upon OA-associated pathologies such as osteophyte formation and pain is unknown. Herein, we investigated early temporal bone and cartilage changes in experimental OA in order to further elucidate the role of PAR2 in OA pathogenesis. Methods OA was induced in wild-type (WT) and PAR2-deficient (PAR2−/−) mice by destabilisation of the medial meniscus (DMM). Inflammation, cartilage degradation and bone changes were monitored using histology and microCT. In gene rescue experiments, PAR2−/− mice were intra-articularly injected with human PAR2 (hPAR2)-expressing adenovirus. Dynamic weight bearing was used as a surrogate of OA-related pain. Results Osteophytes formed within 7 days post-DMM in WT mice but osteosclerosis was only evident from 14 days post induction. Importantly, PAR2 was expressed in the proliferative/hypertrophic chondrocytes present within osteophytes. In PAR2−/− mice, osteophytes developed significantly less frequently but, when present, were smaller and of greater density; no osteosclerosis was observed in these mice up to day 28. The pattern of weight bearing was altered in PAR2−/− mice, suggesting reduced pain perception. The expression of hPAR2 in PAR2−/− mice recapitulated osteophyte formation and cartilage damage similar to that observed in WT mice. However, osteosclerosis was absent, consistent with lack of hPAR2 expression in subchondral bone. Conclusions This study clearly demonstrates PAR2 plays a critical role, via chondrocytes, in osteophyte development and subchondral bone changes, which occur prior to PAR2-mediated cartilage damage. The latter likely occurs independently of OA-related bone changes. PMID:26698846

Alteration of chromophoric dissolved organic matter by solar UV radiation causes rapid changes in bacterial community composition.

PubMed

Piccini, Claudia; Conde, Daniel; Pernthaler, Jakob; Sommaruga, Ruben

2009-09-01

We evaluated the effect of photochemical alterations of chromophoric dissolved organic matter (CDOM) on bacterial abundance, activity and community composition in a coastal lagoon of the Atlantic Ocean with high dissolved organic carbon concentration. On two occasions during the austral summer, bacteria-free water of the lagoon was exposed to different regions of the solar spectrum (full solar radiation, UV-A+PAR, PAR) or kept in the dark. Subsequently, dilution cultures were established with bacterioplankton from the lagoon that were incubated in the pre-exposed water for 5 h in the dark. Cell abundance, activity, and community composition of bacterioplankton were assessed before and after incubation in the different treatments. Changes in absorption, fluorescence, and DOC concentration were used as proxies for CDOM photoalteration. We found a significant CDOM photobleaching signal, DOC loss, as well as a stimulation of bacterial activity in the treatments pre-exposed to UV radiation, suggesting increased bioavailability of DOM. Bacterial community analysis by fluorescence in situ hybridization revealed that this stimulation was mainly accompanied by the specific enrichment of Alpha- and Betaproteobacteria. Thus, our results suggest that CDOM photoalteration not only stimulates bacterioplankton growth, but also induces rapid changes in bacterioplankton composition, which can be of relevance for ecosystem functioning, particularly considering present and future changes in the input of terrestrial CDOM to aquatic systems.

A new empirical model to estimate hourly diffuse photosynthetic photon flux density

NASA Astrophysics Data System (ADS)

Foyo-Moreno, I.; Alados, I.; Alados-Arboledas, L.

2018-05-01

Knowledge of the photosynthetic photon flux density (Qp) is critical in different applications dealing with climate change, plant physiology, biomass production, and natural illumination in greenhouses. This is particularly true regarding its diffuse component (Qpd), which can enhance canopy light-use efficiency and thereby boost carbon uptake. Therefore, diffuse photosynthetic photon flux density is a key driving factor of ecosystem-productivity models. In this work, we propose a model to estimate this component, using a previous model to calculate Qp and furthermore divide it into its components. We have used measurements in urban Granada (southern Spain), of global solar radiation (Rs) to study relationships between the ratio Qpd/Rs with different parameters accounting for solar position, water-vapour absorption and sky conditions. The model performance has been validated with experimental measurements from sites having varied climatic conditions. The model provides acceptable results, with the mean bias error and root mean square error varying between - 0.3 and - 8.8% and between 9.6 and 20.4%, respectively. Direct measurements of this flux are very scarce so that modelling simulations are needed, this is particularly true regarding its diffuse component. We propose a new parameterization to estimate this component using only measured data of solar global irradiance, which facilitates its use for the construction of long-term data series of PAR in regions where continuous measurements of PAR are not yet performed.

Alteration of chromophoric dissolved organic matter by solar UV radiation causes rapid changes in bacterial community composition†

PubMed Central

Piccini, Claudia; Conde, Daniel; Pernthaler, Jakob; Sommaruga, Ruben

2010-01-01

We evaluated the effect of photochemical alterations of chromophoric dissolved organic matter (CDOM) on bacterial abundance, activity and community composition in a coastal lagoon of the Atlantic Ocean with high dissolved organic carbon concentration. On two occasions during the austral summer, bacteria-free water of the lagoon was exposed to different regions of the solar spectrum (full solar radiation, UV-A + PAR, PAR) or kept in the dark. Subsequently, dilution cultures were established with bacterioplankton from the lagoon that were incubated in the pre-exposed water for 5 h in the dark. Cell abundance, activity, and community composition of bacterioplankton were assessed before and after incubation in the different treatments. Changes in absorption, fluorescence, and DOC concentration were used as proxies for CDOM photoalteration. We found a significant CDOM photobleaching signal, DOC loss, as well as a stimulation of bacterial activity in the treatments pre-exposed to UV radiation, suggesting increased bioavailability of DOM. Bacterial community analysis by fluorescence in situ hybridization revealed that this stimulation was mainly accompanied by the specific enrichment of Alpha- and Betaproteobacteria. Thus, our results suggest that CDOM photoalteration not only stimulates bacterioplankton growth, but also induces rapid changes in bacterioplankton composition, which can be of relevance for ecosystem functioning, particularly considering present and future changes in the input of terrestrial CDOM to aquatic systems. PMID:19707620

PAR-2, LGL-1 and the CDC-42 GAP CHIN-1 act in distinct pathways to maintain polarity in the C. elegans embryo

PubMed Central

Beatty, Alexander; Morton, Diane G.; Kemphues, Kenneth

2013-01-01

In the one-cell C. elegans embryo, polarity is maintained by mutual antagonism between the anterior cortical proteins PAR-3, PKC-3, PAR-6 and CDC-42, and the posterior cortical proteins PAR-2 and LGL-1 on the posterior cortex. The mechanisms by which these proteins interact to maintain polarity are incompletely understood. In this study, we investigate the interplay among PAR-2, LGL-1, myosin, the anterior PAR proteins and CDC-42. We find that PAR-2 and LGL-1 affect cortical myosin accumulation by different mechanisms. LGL-1 does not directly antagonize the accumulation of cortical myosin and instead plays a role in regulating PAR-6 levels. By contrast, PAR-2 likely has separate roles in regulating cortical myosin accumulation and preventing the expansion of the anterior cortical domain. We also provide evidence that asymmetry of active CDC-42 can be maintained independently of LGL-1 and PAR-2 by a redundant pathway that includes the CDC-42 GAP CHIN-1. Finally, we show that, in addition to its primary role in regulating the size of the anterior cortical domain via its binding to PAR-6, CDC-42 has a secondary role in regulating cortical myosin that is not dependent on PAR-6. PMID:23536568

Specific and non-specific interactions of ParB with DNA: implications for chromosome segregation

PubMed Central

Taylor, James A.; Pastrana, Cesar L.; Butterer, Annika; Pernstich, Christian; Gwynn, Emma J.; Sobott, Frank; Moreno-Herrero, Fernando; Dillingham, Mark S.

2015-01-01

The segregation of many bacterial chromosomes is dependent on the interactions of ParB proteins with centromere-like DNA sequences called parS that are located close to the origin of replication. In this work, we have investigated the binding of Bacillus subtilis ParB to DNA in vitro using a variety of biochemical and biophysical techniques. We observe tight and specific binding of a ParB homodimer to the parS sequence. Binding of ParB to non-specific DNA is more complex and displays apparent positive co-operativity that is associated with the formation of larger, poorly defined, nucleoprotein complexes. Experiments with magnetic tweezers demonstrate that non-specific binding leads to DNA condensation that is reversible by protein unbinding or force. The condensed DNA structure is not well ordered and we infer that it is formed by many looping interactions between neighbouring DNA segments. Consistent with this view, ParB is also able to stabilize writhe in single supercoiled DNA molecules and to bridge segments from two different DNA molecules in trans. The experiments provide no evidence for the promotion of non-specific DNA binding and/or condensation events by the presence of parS sequences. The implications of these observations for chromosome segregation are discussed. PMID:25572315

PAR-2, LGL-1 and the CDC-42 GAP CHIN-1 act in distinct pathways to maintain polarity in the C. elegans embryo.

PubMed

Beatty, Alexander; Morton, Diane G; Kemphues, Kenneth

2013-05-01

In the one-cell C. elegans embryo, polarity is maintained by mutual antagonism between the anterior cortical proteins PAR-3, PKC-3, PAR-6 and CDC-42, and the posterior cortical proteins PAR-2 and LGL-1 on the posterior cortex. The mechanisms by which these proteins interact to maintain polarity are incompletely understood. In this study, we investigate the interplay among PAR-2, LGL-1, myosin, the anterior PAR proteins and CDC-42. We find that PAR-2 and LGL-1 affect cortical myosin accumulation by different mechanisms. LGL-1 does not directly antagonize the accumulation of cortical myosin and instead plays a role in regulating PAR-6 levels. By contrast, PAR-2 likely has separate roles in regulating cortical myosin accumulation and preventing the expansion of the anterior cortical domain. We also provide evidence that asymmetry of active CDC-42 can be maintained independently of LGL-1 and PAR-2 by a redundant pathway that includes the CDC-42 GAP CHIN-1. Finally, we show that, in addition to its primary role in regulating the size of the anterior cortical domain via its binding to PAR-6, CDC-42 has a secondary role in regulating cortical myosin that is not dependent on PAR-6.

A Conserved Mode of Protein Recognition and Binding in a ParD−ParE Toxin−Antitoxin Complex

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

Dalton, Kevin M.; Crosson, Sean

2010-05-06

Toxin-antitoxin (TA) systems form a ubiquitous class of prokaryotic proteins with functional roles in plasmid inheritance, environmental stress response, and cell development. ParDE family TA systems are broadly conserved on plasmids and bacterial chromosomes and have been well characterized as genetic elements that promote stable plasmid inheritance. We present a crystal structure of a chromosomally encoded ParD-ParE complex from Caulobacter crescentus at 2.6 {angstrom} resolution. This TA system forms an {alpha}{sub 2}{beta}{sub 2} heterotetramer in the crystal and in solution. The toxin-antitoxin binding interface reveals extensive polar and hydrophobic contacts of ParD antitoxin helices with a conserved recognition and bindingmore » groove on the ParE toxin. A cross-species comparison of this complex structure with related toxin structures identified an antitoxin recognition and binding subdomain that is conserved between distantly related members of the RelE/ParE toxin superfamily despite a low level of overall primary sequence identity. We further demonstrate that ParD antitoxin is dimeric, stably folded, and largely helical when not bound to ParE toxin. Thus, the paradigmatic model in which antitoxin undergoes a disorder-to-order transition upon toxin binding does not apply to this chromosomal ParD-ParE TA system.« less

Kallikrein-related peptidase 4 (KLK4) initiates intracellular signaling via protease-activated receptors (PARs). KLK4 and PAR-2 are co-expressed during prostate cancer progression.

PubMed

Ramsay, Andrew J; Dong, Ying; Hunt, Melanie L; Linn, MayLa; Samaratunga, Hemamali; Clements, Judith A; Hooper, John D

2008-05-02

Kallikrein-related peptidase 4 (KLK4) is one of the 15 members of the human KLK family and a trypsin-like, prostate cancer-associated serine protease. Signaling initiated by trypsin-like serine proteases are transduced across the plasma membrane primarily by members of the protease-activated receptor (PAR) family of G protein-coupled receptors. Here we show, using Ca(2+) flux assays, that KLK4 signals via both PAR-1 and PAR-2 but not via PAR-4. Dose-response analysis over the enzyme concentration range 0.1-1000 nM indicated that KLK4-induced Ca(2+) mobilization via PAR-1 is more potent than via PAR-2, whereas KLK4 displayed greater efficacy via the latter PAR. We confirmed the specificity of KLK4 signaling via PAR-2 using in vitro protease cleavage assays and anti-phospho-ERK1/2/total ERK1/2 Western blot analysis of PAR-2-overexpressing and small interfering RNA-mediated receptor knockdown cell lines. Consistently, confocal microscopy analyses indicated that KLK4 initiates loss of PAR-2 from the cell surface and receptor internalization. Immunohistochemical analysis indicated the co-expression of agonist and PAR-2 in primary prostate cancer and bone metastases, suggesting that KLK4 signaling via this receptor will have pathological relevance. These data provide insight into KLK4-mediated cell signaling and suggest that signals induced by this enzyme via PARs may be important in prostate cancer.

Par-4-mediated recruitment of Amida to the actin cytoskeleton leads to the induction of apoptosis

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

Boosen, Meike; Vetterkind, Susanne; Koplin, Ansgar

Par-4 (prostate apoptosis response-4) sensitizes cells to apoptotic stimuli, but the exact mechanisms are still poorly understood. Using Par-4 as bait in a yeast two-hybrid screen, we identified Amida as a novel interaction partner, a ubiquitously expressed protein which has been suggested to be involved in apoptotic processes. Complex formation of Par-4 and Amida occurs in vitro and in vivo and is mediated via the C-termini of both proteins, involving the leucine zipper of Par-4. Amida resides mainly in the nucleus but displays nucleo-cytoplasmic shuttling in heterokaryons. Upon coexpression with Par-4 in REF52.2 cells, Amida translocates to the cytoplasm andmore » is recruited to actin filaments by Par-4, resulting in enhanced induction of apoptosis. The synergistic effect of Amida/Par-4 complexes on the induction of apoptosis is abrogated when either Amida/Par-4 complex formation or association of these complexes with the actin cytoskeleton is impaired, indicating that the Par-4-mediated relocation of Amida to the actin cytoskeleton is crucial for the pro-apoptotic function of Par-4/Amida complexes in REF52.2 cells. The latter results in enhanced phosphorylation of the regulatory light chain of myosin II (MLC) as has previously been shown for Par-4-mediated recruitment of DAP-like kinase (Dlk), suggesting that the recruitment of nuclear proteins involved in the regulation of apoptotic processes to the actin filament system by Par-4 represents a potent mechanism how Par-4 can trigger apoptosis.« less

Brownian Ratchet Mechanism for Faithful Segregation of Low-Copy-Number Plasmids.

PubMed

Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

2017-04-11

Bacterial plasmids are extrachromosomal DNA that provides selective advantages for bacterial survival. Plasmid partitioning can be remarkably robust. For high-copy-number plasmids, diffusion ensures that both daughter cells inherit plasmids after cell division. In contrast, most low-copy-number plasmids need to be actively partitioned by a conserved tripartite ParA-type system. ParA is an ATPase that binds to chromosomal DNA; ParB is the stimulator of the ParA ATPase and specifically binds to the plasmid at a centromere-like site, parS. ParB stimulation of the ParA ATPase releases ParA from the bacterial chromosome, after which it takes a long time to reset its DNA-binding affinity. We previously demonstrated in vitro that the ParA system can exploit this biochemical asymmetry for directed cargo transport. Multiple ParA-ParB bonds can bridge a parS-coated cargo to a DNA carpet, and they can work collectively as a Brownian ratchet that directs persistent cargo movement with a ParA-depletion zone trailing behind. By extending this model, we suggest that a similar Brownian ratchet mechanism recapitulates the full range of actively segregated plasmid motilities observed in vivo. We demonstrate that plasmid motility is tuned as the replenishment rate of the ParA-depletion zone progressively increases relative to the cargo speed, evolving from diffusion to pole-to-pole oscillation, local excursions, and, finally, immobility. When the plasmid replicates, the daughters largely display motilities similar to that of their mother, except that when the single-focus progenitor is locally excursive, the daughter foci undergo directed segregation. We show that directed segregation maximizes the fidelity of plasmid partition. Given that local excursion and directed segregation are the most commonly observed modes of plasmid motility in vivo, we suggest that the operation of the ParA-type partition system has been shaped by evolution for high fidelity of plasmid segregation. Published by Elsevier Inc.

Population attributable risk of factors associated with the repetition of self-harm behaviour in young people presenting to clinical services: a systematic review and meta-analysis.

PubMed

Witt, Katrina; Milner, Allison; Spittal, Matthew J; Hetrick, Sarah; Robinson, Jo; Pirkis, Jane; Carter, Gregory

2018-02-03

The repetition of hospital-treated self-harm by young people is common. However, little work has summarised the modifiable factors associated with this. A thorough understanding of those factors most strongly associated with repetition could guide the development of relevant clinical interventions. We systematically reviewed four databases (EMBASE, Medline, PubMed and PsycINFO) until 15 April 2016 to identify all observational studies of factors for the repetition of self-harm or suicide reattempts (together referred to as 'self-harm behaviour') in young people. We quantified the magnitude of association with odds ratios (OR) and 95% confidence intervals (CIs) and calculated the population attributable risk (PAR) and population preventable fraction (PPF) for modifiable factors to provide an indication of the potential impact in reducing subsequent self-harm behaviour in this population. Seventeen studies were included comprising 10,726 participants. Borderline personality disorder (OR 3.47, 95% CI 1.84-6.53; PAR 42.4%), any personality disorder (OR 2.54, 95% CI 1.71-3.78; PAR 16.3%), and any mood disorder (OR 2.16, 95% CI 1.09-4.29; PAR 42.2%) are important modifiable risk factors. Severity of hopelessness (OR 2.95, 95% CI 1.74-5.01), suicidal ideation (OR 2.01, 95% CI 1.43-2.81), and previous sexual abuse (OR 1.52, 95% CI 1.02-2.28; PAR 12.8%) are also associated with repetition of self-harm. We recommend that clinical services should focus on identifying key modifiable risk factors at the individual patient level, whilst the reduction of exposure to child and adolescent sexual abuse would also be a useful goal for public health interventions.

Spine abnormalities depicted by magnetic resonance imaging in adolescent rowers.

PubMed

Maurer, Marvin; Soder, Ricardo Bernardi; Baldisserotto, Matteo

2011-02-01

Most lesions of the spine of athletes, which often are detected incidentally, do not cause important symptoms or make the athletes discontinue their physical activities. To better understand the significance of these lesions, new imaging studies have been conducted with asymptomatic athletes in several sports, aiming to detect potentially deleterious and disabling abnormalities. To compare the magnetic resonance imaging (MRI) lumbar spine findings in a group of asymptomatic adolescent rowers and in a control group of adolescents matched according to age and sex who do not practice any regular physical activity. Cohort study (prevalence); Level of evidence, 3. Our study evaluated 44 asymptomatic adolescent boys distributed in 2 groups of 22 rowers and 22 control subjects. All the examinations were performed using a 0.35-T open-field MRI unit and evaluated by 2 experienced radiologists blinded to the study groups. Each MRI scan was analyzed for the presence of disc degeneration/desiccation, herniated or bulging disc, pars interarticularis stress reaction, and spondylolysis. The Student t test and the Fisher exact test were used for statistical analyses. Nine rowers (40.9%) had at least 1 abnormality detected by MRI in the lumbar spine, whereas only 2 participants (9.1%) in the control group had at least 1 MRI abnormality (P = .03). Seven disc changes (31.8%) and 6 pars abnormalities (27.3%) were found in the group of elite rowers. In the control group, 3 disc changes (13.6%) and no pars abnormalities were found in the MR scans. The comparison between groups showed statistically significant differences in stress reaction of the pars articularis. Disc disease and pars interarticularis stress reaction are prevalent abnormalities of the lumbar spine of high-performance rowers.

Neutrophil proteinase 3 (PR3) acts on protease-activated receptor-2 (PAR-2) to enhance vascular endothelial cell barrier function

PubMed Central

Kuckleburg, Christopher J.; Newman, Peter J.

2013-01-01

The principle role of the vascular endothelium is to present a semi-impermeable barrier to soluble factors and circulating cells, while still permitting the passage of leukocytes from the bloodstream into the tissue. The process of diapedesis involves the selective disruption of endothelial cell junctions, an event that could in theory compromise vascular integrity. It is therefore somewhat surprising that neutrophil transmigration does not significantly impair endothelial barrier function. We examined whether neutrophils might secrete factors that promote vascular integrity during the latter stages of neutrophil transmigration, and found that neutrophil proteinase 3 (PR3) – a serine protease harbored in azurophilic granules – markedly enhanced barrier function in endothelial cells. PR3 functioned in this capacity both in its soluble form and in a complex with cell-surface NB1. PR3-mediated enhancement of endothelial cell junctional integrity required its proteolytic activity, as well as endothelial cell expression of the protease-activated receptor, PAR-2. Importantly, PR3 suppressed the vascular permeability changes and disruption of junctional proteins induced by the action of PAR-1 agonists. These findings establish the potential for neutrophil-derived PR3 to play a role in reestablishing vascular integrity following leukocyte transmigration, and in protecting endothelial cells from PAR-1-induced permeability changes that occur during thrombotic and inflammatory events. PMID:23202369

Snowy backgrounds enhance the absorption of visible light in forest canopies

NASA Astrophysics Data System (ADS)

Pinty, B.; Widlowski, J.-L.; Verstraete, M. M.; Andredakis, I.; Arino, O.; Clerici, M.; Kaminski, T.; Taberner, M.

2011-03-01

The fraction of radiation absorbed in the canopy depends on the amount and angular distribution of the solar irradiance reaching the top of the canopy as well as the fraction of this irradiance that is transmitted through the canopy gaps and reflected back to the vegetation by the background. This contribution shows that the presence of snow on forest floors enhances the fraction of absorbed Photosynthetically Active Radiation (PAR). A global analysis of satellite-derived products reveals that this enhancement affects evergreen and deciduous forests of the boreal zone. This snow-related effect may usefully contribute to the photosynthesis process in evergreen forests especially during spring time when radiation conditions are marginal but other physiological constraints (such as temperature) permit the necessary biochemical functions to take place.

Analyse de la dégradation thermique du Poly(éther éther cétone)

NASA Astrophysics Data System (ADS)

Courvoisier, Emilie; Bicaba, Yoann; Colin, Xavier

2018-03-01

La dégradation thermique du PEEK a été étudiée à l'état caoutchoutique dans de larges intervalles de température (entre 180 et 320 °C) et de pression partielle d'oxygène (entre 0,21 et 50 bars). Tout d'abord, les mécanismes de vieillissement thermique ont été analysés et élucidés par spectroscopie IRTF et par calorimétrie différentielle (DSC) sur des films de PEEK suffisamment minces (entre 10 et 60 μm d'épaisseur) pour s'affranchir totalement des effets de la diffusion d'oxygène. L'oxydation se produit sur les cycles aromatiques provoquant la croissance de cinq nouvelles bandes d'absorption IR centrées à 3650, 3525, 1780, 1740 et 1718 cm-1 et attribuées aux vibrations d'élongation des liaisons O-H du phénol et de l'acide benzoïque, et des liaisons C-O de l'anhydride benzoïque, du benzoate de phényle et de la fluorénone respectivement. De plus, l'oxydation conduit à une large prédominance de la réticulation sur les coupures de chaîne (augmentation de Tg) empêchant le recuit du PEEK, en particulier lorsque la température d'exposition est supérieure au pied du pic de fusion. Enfin, les conséquences de l'oxydation sur les propriétés élastiques ont été analysées et élucidées par micro-indentation sur des sections droites préalablement polies de plaquettes de PEEK de 3 mm d'épaisseur. Les variations du module d'Young et du taux de cristallinité se corrèlent parfaitement, vérifiant ainsi la relation de Tobolsky.

UV/PAR radiations and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009

NASA Astrophysics Data System (ADS)

Para, J.; Charrière, B.; Matsuoka, A.; Miller, W. L.; Rontani, J. F.; Sempéré, R.

2012-11-01

Water masses from the Beaufort Sea in the Arctic Ocean were evaluated for dissolved organic carbon (DOC), and optical characteristics including UV and PAR diffuse attenuation (Kd), and chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July to 27 August). Even with relatively low mean daily solar radiation incident on the sea surface (0.12 ± 0.03, 8.46 ± 1.64 and 18.09 ± 4.20 kJ m-2 for UV-B (305 nm), UV-A (380 nm) and PAR, respectively), we report significant light penetration with 10% irradiance depths (Z10% (λ)) reaching 9.5 m for 340 nm (UV-A) radiation in the Eastern sector and 4.5 m in the Mackenzie River influenced area (Western sector). Spectral absorption coefficients (aCDOM (350 nm) (m-1)) were significantly correlated to both diffuse attenuation coefficients (Kd) in the UV-A and UV-B and to DOC concentrations. This indicates CDOM as the dominant attenuator of UV solar radiation and suggests its use as an optical proxy for DOC concentrations in this region. Extrapolating CDOM to DOC relationships, we estimate that ~ 16% of the DOC in the Mackenzie River does not absorb radiation at 350 nm. DOC and CDOM discharges by the Mackenzie River during the MALINA Cruise are estimated as ~ 0.22 TgC and 0.18 TgC, respectively. Three dissolved fluorescent components (C1-C3) were identified by fluorescence Excitation/Emission Matrix Spectroscopy (EEMS) and PARAFAC analysis. Our results showed an in-situ biological component (C1) that co-dominated with a terrestrial humic-like component (C2) in the Mackenzie Delta sector, whereas the protein-like (C3) component dominated in the saltiest waters of the North East sector.

The role of pars flaccida in human middle ear sound transmission.

PubMed

Aritomo, H; Goode, R L; Gonzalez, J

1988-04-01

The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

Dimerization controls the lipid raft partitioning of uPAR/CD87 and regulates its biological functions

PubMed Central

Cunningham, Orla; Andolfo, Annapaola; Santovito, Maria Lisa; Iuzzolino, Lucia; Blasi, Francesco; Sidenius, Nicolai

2003-01-01

The urokinase-type plasminogen activator receptor (uPAR/CD87) is a glycosylphosphatidylinositol-anchored membrane protein with multiple functions in extracellular proteolysis, cell adhesion, cell migration and proliferation. We now report that cell surface uPAR dimerizes and that dimeric uPAR partitions preferentially to detergent-resistant lipid rafts. Dimerization of uPAR did not require raft partitioning as the lowering of membrane cholesterol failed to reduce dimerization and as a transmembrane uPAR chimera, which does not partition to lipid rafts, also dimerized efficiently. While uPA bound to uPAR independently of its membrane localization and dimerization status, uPA-induced uPAR cleavage was strongly accelerated in lipid rafts. In contrast to uPA, the binding of Vn occurred preferentially to raft- associated dimeric uPAR and was completely blocked by cholesterol depletion. PMID:14609946

Structures of actin-like ParM filaments show architecture of plasmid-segregating spindles.

PubMed

Bharat, Tanmay A M; Murshudov, Garib N; Sachse, Carsten; Löwe, Jan

2015-07-02

Active segregation of Escherichia coli low-copy-number plasmid R1 involves formation of a bipolar spindle made of left-handed double-helical actin-like ParM filaments. ParR links the filaments with centromeric parC plasmid DNA, while facilitating the addition of subunits to ParM filaments. Growing ParMRC spindles push sister plasmids to the cell poles. Here, using modern electron cryomicroscopy methods, we investigate the structures and arrangements of ParM filaments in vitro and in cells, revealing at near-atomic resolution how subunits and filaments come together to produce the simplest known mitotic machinery. To understand the mechanism of dynamic instability, we determine structures of ParM filaments in different nucleotide states. The structure of filaments bound to the ATP analogue AMPPNP is determined at 4.3 Å resolution and refined. The ParM filament structure shows strong longitudinal interfaces and weaker lateral interactions. Also using electron cryomicroscopy, we reconstruct ParM doublets forming antiparallel spindles. Finally, with whole-cell electron cryotomography, we show that doublets are abundant in bacterial cells containing low-copy-number plasmids with the ParMRC locus, leading to an asynchronous model of R1 plasmid segregation.

A three-dimensional ParF meshwork assembles through the nucleoid to mediate plasmid segregation

PubMed Central

McLeod, Brett N.; Allison-Gamble, Gina E.; Barge, Madhuri T.; Tonthat, Nam K.; Schumacher, Maria A.; Hayes, Finbarr

2017-01-01

Abstract Genome segregation is a fundamental step in the life cycle of every cell. Most bacteria rely on dedicated DNA partition proteins to actively segregate chromosomes and low copy-number plasmids. Here, by employing super resolution microscopy, we establish that the ParF DNA partition protein of the ParA family assembles into a three-dimensional meshwork that uses the nucleoid as a scaffold and periodically shuttles between its poles. Whereas ParF specifies the territory for plasmid trafficking, the ParG partner protein dictates the tempo of ParF assembly cycles and plasmid segregation events by stimulating ParF adenosine triphosphate hydrolysis. Mutants in which this ParG temporal regulation is ablated show partition deficient phenotypes as a result of either altered ParF structure or dynamics and indicate that ParF nucleoid localization and dynamic relocation, although necessary, are not sufficient per se to ensure plasmid segregation. We propose a Venus flytrap model that merges the concepts of ParA polymerization and gradient formation and speculate that a transient, dynamic network of intersecting polymers that branches into the nucleoid interior is a widespread mechanism to distribute sizeable cargos within prokaryotic cells. PMID:28034957

Estimation of photosynthetically available radiation (PAR) from OCEANSAT-I OCM using a simple atmospheric radiative transfer model

NASA Astrophysics Data System (ADS)

Tripathy, Madhumita; Raman, Mini; Chauhan, Prakash

2015-10-01

Photosynthetically available radiation (PAR) is an important variable for radiation budget, marine and terrestrial ecosystem models. OCEANSAT-1 Ocean Color Monitor (OCM) PAR was estimated using two different methods under both clear and cloudy sky conditions. In the first approach, aerosol optical depth (AOD) and cloud optical depth (COD) were estimated from OCEANSAT-1 OCM TOA (top-of-atmosphere) radiance data on a pixel by pixel basis and PAR was estimated from extraterrestrial solar flux for fifteen spectral bands using a radiative transfer model. The second approach used TOA radiances measured by OCM in the PAR spectral range to compute PAR. This approach also included surface albedo and cloud albedo as inputs. Comparison between OCEANSAT-1 OCM PAR at noon with in situ measured PAR shows that root mean square difference was 5.82% for the method I and 7.24% for the method II in daily time scales. Results indicate that methodology adopted to estimate PAR from OCEANSAT-1 OCM can produce reasonably accurate PAR estimates over the tropical Indian Ocean region. This approach can be extended to OCEANSAT-2 OCM and future OCEANSAT-3 OCM data for operational estimation of PAR for regional marine ecosystem applications.

Factor X/Xa elicits protective signaling responses in endothelial cells directly via PAR-2 and indirectly via endothelial protein C receptor-dependent recruitment of PAR-1.

PubMed

Bae, Jong-Sup; Yang, Likui; Rezaie, Alireza R

2010-11-05

We recently demonstrated that the Gla domain-dependent interaction of protein C with endothelial protein C receptor (EPCR) leads to dissociation of the receptor from caveolin-1 and recruitment of PAR-1 to a protective signaling pathway. Thus, the activation of PAR-1 by either thrombin or PAR-1 agonist peptide elicited a barrier-protective response if endothelial cells were preincubated with protein C. In this study, we examined whether other vitamin K-dependent coagulation protease zymogens can modulate PAR-dependent signaling responses in endothelial cells. We discovered that the activation of both PAR-1 and PAR-2 in endothelial cells pretreated with factor FX (FX)-S195A, but not other procoagulant protease zymogens, also results in initiation of protective intracellular responses. Interestingly, similar to protein C, FX interaction with endothelial cells leads to dissociation of EPCR from caveolin-1 and recruitment of PAR-1 to a protective pathway. Further studies revealed that, FX activated by factor VIIa on tissue factor bearing endothelial cells also initiates protective signaling responses through the activation of PAR-2 independent of EPCR mobilization. All results could be recapitulated by the receptor agonist peptides to both PAR-1 and PAR-2. These results suggest that a cross-talk between EPCR and an unknown FX/FXa receptor, which does not require interaction with the Gla domain of FX, recruits PAR-1 to protective signaling pathways in endothelial cells.

Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR(2) ) is involved in vascular function.

PubMed

Bucci, M; Vellecco, V; Harrington, L; Brancaleone, V; Roviezzo, F; Mattace Raso, G; Ianaro, A; Lungarella, G; De Palma, R; Meli, R; Cirino, G

2013-01-01

Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR(2) and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models. Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR(2) activating peptide (AP) was used as a PAR(2) agonist. Aortas harvested from TLR4(-/-) mice were also used to characterize the PAR(2) response. PAR(2) , but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR(2) AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR(2) AP-induced vasorelaxation and PAR(2) AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4(-/-) mice, the expression of PAR(2) was reduced and the PAR(2) AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective. Cross-talk between PAR(2) and TLR4 contributes to vascular homeostasis. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR2) is involved in vascular function

PubMed Central

Bucci, M; Vellecco, V; Harrington, L; Brancaleone, V; Roviezzo, F; Mattace Raso, G; Ianaro, A; Lungarella, G; De Palma, R; Meli, R; Cirino, G

2013-01-01

Background and Purpose Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR2 and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models. Experimental Approach Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR2 activating peptide (AP) was used as a PAR2 agonist. Aortas harvested from TLR4–/– mice were also used to characterize the PAR2 response. Key Results PAR2, but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR2AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR2AP-induced vasorelaxation and PAR2AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4–/– mice, the expression of PAR2 was reduced and the PAR2AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective. Conclusions and Implications Cross-talk between PAR2 and TLR4 contributes to vascular homeostasis. PMID:22957757

PAR2 (Protease-Activated Receptor 2) Deficiency Attenuates Atherosclerosis in Mice.

PubMed

Jones, Shannon M; Mann, Adrien; Conrad, Kelsey; Saum, Keith; Hall, David E; McKinney, Lisa M; Robbins, Nathan; Thompson, Joel; Peairs, Abigail D; Camerer, Eric; Rayner, Katey J; Tranter, Michael; Mackman, Nigel; Owens, A Phillip

2018-06-01

PAR2 (protease-activated receptor 2)-dependent signaling results in augmented inflammation and has been implicated in the pathogenesis of several autoimmune conditions. The objective of this study was to determine the effect of PAR2 deficiency on the development of atherosclerosis. PAR2 mRNA and protein expression is increased in human carotid artery and mouse aortic arch atheroma versus control carotid and aortic arch arteries, respectively. To determine the effect of PAR2 deficiency on atherosclerosis, male and female low-density lipoprotein receptor-deficient ( Ldlr -/- ) mice (8-12 weeks old) that were Par2 +/+ or Par2 -/- were fed a fat- and cholesterol-enriched diet for 12 or 24 weeks. PAR2 deficiency attenuated atherosclerosis in the aortic sinus and aortic root after 12 and 24 weeks. PAR2 deficiency did not alter total plasma cholesterol concentrations or lipoprotein distributions. Bone marrow transplantation showed that PAR2 on nonhematopoietic cells contributed to atherosclerosis. PAR2 deficiency significantly attenuated levels of the chemokines Ccl2 and Cxcl1 in the circulation and macrophage content in atherosclerotic lesions. Mechanistic studies using isolated primary vascular smooth muscle cells showed that PAR2 deficiency is associated with reduced Ccl2 and Cxcl1 mRNA expression and protein release into the supernatant resulting in less monocyte migration. Our results indicate that PAR2 deficiency is associated with attenuation of atherosclerosis and may reduce lesion progression by blunting Ccl2 - and Cxcl1 -induced monocyte infiltration. © 2018 American Heart Association, Inc.

Resistance to Plum Pox Virus (PPV) in apricot (Prunus armeniaca L.) is associated with down-regulation of two MATHd genes.

PubMed

Zuriaga, Elena; Romero, Carlos; Blanca, Jose Miguel; Badenes, Maria Luisa

2018-01-27

Plum pox virus (PPV), causing Sharka disease, is one of the main limiting factors for Prunus production worldwide. In apricot (Prunus armeniaca L.) the major PPV resistance locus (PPVres), comprising ~ 196 kb, has been mapped to the upper part of linkage group 1. Within the PPVres, 68 genomic variants linked in coupling to PPV resistance were identified within 23 predicted transcripts according to peach genome annotation. Taking into account the predicted functions inferred from sequence homology, some members of a cluster of meprin and TRAF-C homology domain (MATHd)-containing genes were pointed as PPV resistance candidate genes. Here, we have characterized the global apricot transcriptome response to PPV-D infection identifying six PPVres locus genes (ParP-1 to ParP-6) differentially expressed in resistant/susceptible cultivars. Two of them (ParP-3 and ParP-4), that encode MATHd proteins, appear clearly down-regulated in resistant cultivars, as confirmed by qRT-PCR. Concurrently, variant calling was performed using whole-genome sequencing data of 24 apricot cultivars (10 PPV-resistant and 14 PPV-susceptible) and 2 wild relatives (PPV-susceptible). ParP-3 and ParP-4, named as Prunus armeniaca PPVres MATHd-containing genes (ParPMC), are the only 2 genes having allelic variants linked in coupling to PPV resistance. ParPMC1 has 1 nsSNP, while ParPMC2 has 15 variants, including a 5-bp deletion within the second exon that produces a frameshift mutation. ParPMC1 and ParPMC2 are adjacent and highly homologous (87.5% identity) suggesting they are paralogs originated from a tandem duplication. Cultivars carrying the ParPMC2 resistant (mutated) allele show lack of expression in both ParPMC2 and especially ParPMC1. Accordingly, we hypothesize that ParPMC2 is a pseudogene that mediates down-regulation of its functional paralog ParPMC1 by silencing. As a whole, results strongly support ParPMC1 and/or ParPMC2 as host susceptibility genes required for PPV infection which silencing may confer PPV resistance trait. This finding may facilitate resistance breeding by marker-assisted selection and pave the way for gene edition approaches in Prunus.

Protease Activated Receptor-2 Expression and Function in Asthmatic Bronchial Smooth Muscle

PubMed Central

Gilbert, Guillaume; Carvalho, Gabrielle; Trian, Thomas; Ozier, Annaig; Gillibert-Duplantier, Jennifer; Ousova, Olga; Maurat, Elise; Thumerel, Matthieu; Quignard, Jean-François; Girodet, Pierre-Olivier; Marthan, Roger; Berger, Patrick

2014-01-01

Asthmatic bronchial smooth muscle (BSM) is characterized by structural remodeling associated with mast cell infiltration displaying features of chronic degranulation. Mast cell-derived tryptase can activate protease activated receptor type-2 (PAR-2) of BSM cells. The aims of the present study were (i) to evaluate the expression of PAR-2 in both asthmatic and non asthmatic BSM cells and, (ii) to analyze the effect of prolonged stimulation of PAR-2 in asthmatic BSM cells on cell signaling and proliferation. BSM cells were obtained from both 33 control subjects and 22 asthmatic patients. PAR-2 expression was assessed by flow cytometry, western blot and quantitative RT-PCR. Calcium response, transduction pathways and proliferation were evaluated before and following PAR-2 stimulation by SLIGKV-NH2 or trypsin for 1 to 3 days. Asthmatic BSM cells expressed higher basal levels of functional PAR-2 compared to controls in terms of mRNA, protein expression and calcium response. When PAR-2 expression was increased by means of lentivirus in control BSM cells to a level similar to that of asthmatic cells, PAR-2-induced calcium response was then similar in both types of cell. However, repeated PAR-2 stimulations increased the proliferation of asthmatic BSM cells but not that of control BSM cells even following lentiviral over-expression of PAR-2. Such an increased proliferation was related to an increased phosphorylation of ERK in asthmatic BSM cells. In conclusion, we have demonstrated that asthmatic BSM cells express increased baseline levels of functional PAR-2. This higher basal level of PAR-2 accounts for the increased calcium response to PAR-2 stimulation, whereas the increased proliferation to repeated PAR-2 stimulation is related to increased ERK phosphorylation. PMID:24551046

Increased Expression of Cathelicidin by Direct Activation of Protease-Activated Receptor 2: Possible Implications on the Pathogenesis of Rosacea

PubMed Central

Kim, Ji Young; Kim, Yoon Jee; Lim, Beom Jin; Sohn, Hyo Jung; Shin, Dongyun

2014-01-01

Purpose Recent findings of increased cathelicidin protein and its proteolytic fragments in rosacea suggest a pathogenic role for cathelicidin in this disease. The relationship between cathelicidin and protease-activated receptor 2 (PAR-2) is therefore of interest, as PAR-2, expressed principally in keratinocytes, regulates pro-inflammatory cytokine expression in the skin. The purpose of this study was to determine the relationship between expression of PAR-2 and cathelicidin in rosacea and to test the effect of direct PAR-2 activation on cathelicidin expression in keratinocytes. Materials and Methods Samples from 40 patients with clinicopathologic diagnosis of rosacea and facial skin tissue samples from 20 patients with no specific findings or milium without inflammation were retrieved. Intensities of immunohistochemical staining for PAR-2 and cathelicidin were compared between normal and rosacea-affected skin tissues. Additionally, correlations between PAR-2 and cathelicidin staining intensities within rosacea patients were analyzed. In cultured keratinocytes, changes in PAR-2, cathelicidin, and vascular endothelial growth factor (VEGF) mRNA and protein were analyzed after treatment with PAR-2 activating peptide (AP). Results Cathelicidin expression was significantly higher in rosacea skin tissues than in normal tissues (p<0.001), while PAR-2 expression was not significantly higher in rosacea tissues than in normal skin tissues. A positive correlation between PAR-2 and cathelicidin within rosacea samples was observed (R=0.330, p=0.037). After treatment of PAR-2 AP, both mRNA and protein levels for PAR-2, cathelicidin, and VEGF significantly increased in cultured keratinocytes, compared with PAR-2 control peptide treatment. Conclusion PAR-2 may participate in the pathogenesis of rosacea through activation of cathelicidin LL-37, a mediator of innate immune responses in the skin. PMID:25323904

Involvement of proteinase activated receptor-2 in the vascular response to sphingosine 1-phosphate.

PubMed

Roviezzo, Fiorentina; De Angelis, Antonella; De Gruttola, Luana; Bertolino, Antonio; Sullo, Nikol; Brancaleone, Vincenzo; Bucci, Mariarosaria; De Palma, Raffaele; Urbanek, Konrad; D'Agostino, Bruno; Ianaro, Angela; Sorrentino, Raffaella; Cirino, Giuseppe

2014-04-01

S1P (sphingosine 1-phosphate) represents one of the key latest additions to the list of vasoactive substances that modulate vascular tone. PAR-2 (proteinase activated receptor-2) has been shown to be involved in cardiovascular function. In the present study, we investigated the involvement of PAR-2 in S1P-induced effect on vascular tone. The present study has been performed by using isolated mouse aortas. Both S1P and PAR-2 agonists induced endothelium-dependent vasorelaxation. L-NAME (N(G)-nitro-L-arginine methyl ester) and wortmannin abrogated the S1P-induced vasorelaxatioin, while significantly inhibiting the PAR-2-mediated effect. Either ENMD1068, a PAR-2 antagonist, or gabexate, a serine protease inhibitor, significantly inhibited S1P-induced vasorelaxation. Aortic tissues harvested from mice overexpressing PAR-2 displayed a significant increase in vascular response to S1P as opposed to PAR-2-null mice. Immunoprecipitation and immunofluorescence studies demonstrated that S1P(1) interacted with PAR-2 and co-localized with PAR-2 on the vascular endothelial surface. Furthermore, S1P administration to vascular tissues triggered PAR-2 mobilization from the plasma membrane to the perinuclear area; S1P-induced translocation of PAR-2 was abrogated when aortic rings were pre-treated with ENMD1068 or when caveolae dysfunction occurred. Similarly, experiments performed in cultured endothelial cells (human umbilical vein endothelial cells) showed a co-localization of S1P(1) and PAR2, as well as the ability of S1P to induce PAR-2 trafficking. Our results suggest that S1P induces endothelium-dependent vasorelaxation mainly through S1P(1) and involves PAR-2 transactivation.

Expression of Par3 polarity protein correlates with poor prognosis in ovarian cancer.

PubMed

Nakamura, Hiroe; Nagasaka, Kazunori; Kawana, Kei; Taguchi, Ayumi; Uehara, Yuriko; Yoshida, Mitsuyo; Sato, Masakazu; Nishida, Haruka; Fujimoto, Asaha; Inoue, Tomoko; Adachi, Katsuyuki; Nagamatsu, Takeshi; Arimoto, Takahide; Oda, Katsutoshi; Osuga, Yutaka; Fujii, Tomoyuki

2016-11-17

Previous studies have shown that the cell polarity protein partitioning defective 3 (Par3) plays an essential role in the formation of tight junctions and definition of apical-basal polarity. Aberrant function of this protein has been reported to be involved in epithelial-mesenchymal transition (EMT) and cancer invasion. The aim of this study was to examine the functional mechanism of Par3 in ovarian cancer. First, we investigated the association between Par3 expression level and survival of 50 ovarian cancer patients. Next, we conducted an in vitro analysis of ovarian cancer cell lines, focusing on the cell line JHOC5, to investigate Par3 function. To investigate the function of Par3 in invasion, the IL-6/STAT3 pathway was analyzed upon Par3 knockdown with siRNA. The effect of siRNA treatment was assessed by qPCR, ELISA, and western blotting. Invasiveness and cell proliferation following treatment with siRNA against Par3 were investigated using Matrigel chamber, wound healing, and cell proliferation assays. Expression array data for ovarian cancer patient samples revealed low Par3 expression was significantly associated with good prognosis. Univariate analysis of clinicopathological factors revealed significant association between high Par3 levels and peritoneal dissemination at the time of diagnosis. Knockdown of Par3 in JHOC5 cells suppressed cell invasiveness, migration, and cell proliferation with deregulation of IL-6/STAT3 activity. Taken together, these results suggest that Par3 expression is likely involved in ovarian cancer progression, especially in peritoneal metastasis. The underlying mechanism may be that Par3 modulates IL-6 /STAT3 signaling. Here, we propose that the expression of Par3 in ovarian cancer may control disease outcome.

Urokinase receptor expression involves tyrosine phosphorylation of phosphoglycerate kinase.

PubMed

Shetty, Praveenkumar; Velusamy, Thirunavukkarasu; Bhandary, Yashodhar P; Liu, Ming C; Shetty, Sreerama

2010-02-01

The interaction of urokinase-type plasminogen activator (uPA) with its receptor, uPAR, plays a central role in several pathophysiological processes, including cancer. uPA induces its own cell surface receptor expression through stabilization of uPAR mRNA. The mechanism involves binding of a 51 nt uPAR mRNA coding sequence with phosphoglycerate kinase (PGK) to down regulate cell surface uPAR expression. Tyrosine phosphorylation of PGK mediated by uPA treatment enhances uPAR mRNA stabilization. In contrast, inhibition of tyrosine phosphorylation augments PGK binding to uPAR mRNA and attenuates uPA-induced uPAR expression. Mapping the specific peptide region of PGK indicated that its first quarter (amino acids 1-100) interacts with uPAR mRNA. To determine if uPAR expression by uPA is regulated through activation of tyrosine residues of PGK, we mutated the specific tyrosine residue and tested mutant PGK for its ability to interfere with uPAR expression. Inhibition of tyrosine phosphorylation by mutating Y76 residue abolished uPAR expression induced by uPA treatment. These findings collectively demonstrate that Y76 residue present in the first quarter of the PGK molecule is involved in lung epithelial cell surface uPAR expression. This region can effectively mimic the function of a whole PGK molecule in inhibiting tumor cell growth.

A family of ParA-like ATPases promotes cell pole maturation by facilitating polar localization of chemotaxis proteins

PubMed Central

Ringgaard, Simon; Schirner, Kathrin; Davis, Brigid M.; Waldor, Matthew K.

2011-01-01

Stochastic processes are thought to mediate localization of membrane-associated chemotaxis signaling clusters in peritrichous bacteria. Here, we identified a new family of ParA-like ATPases (designated ParC [for partitioning chemotaxis]) encoded within chemotaxis operons of many polar-flagellated γ-proteobacteria that actively promote polar localization of chemotaxis proteins. In Vibrio cholerae, a single ParC focus is found at the flagellated old pole in newborn cells, and later bipolar ParC foci develop as the cell matures. The cell cycle-dependent redistribution of ParC occurs by its release from the old pole and subsequent relocalization at the new pole, consistent with a “diffusion and capture” model for ParC dynamics. Chemotaxis proteins encoded in the same cluster as ParC have a similar unipolar-to-bipolar transition; however, they reach the new pole after the arrival of ParC. Cells lacking ParC exhibit aberrantly localized foci of chemotaxis proteins, reduced chemotaxis, and altered motility, which likely accounts for their enhanced colonization of the proximal small intestine in an animal model of cholera. Collectively, our findings indicate that ParC promotes the efficiency of chemotactic signaling processes. In particular, ParC-facilitated development of a functional chemotaxis apparatus at the new pole readies this site for its development into a functional old pole after cell division. PMID:21764856

Proteinase activated-receptors-associated signaling in the control of gastric cancer

PubMed Central

Sedda, Silvia; Marafini, Irene; Caruso, Roberta; Pallone, Francesco; Monteleone, Giovanni

2014-01-01

Gastric cancer (GC) is the fourth most common cancer in the world and the second cause of cancer-related death. Gastric carcinogenesis is a multifactorial process, in which environmental and genetic factors interact to activate multiple intracellular signals thus leading to uncontrolled growth and survival of GC cells. One such a pathway is regulated by proteinase activated-receptors (PARs), seven transmembrane-spanning domain G protein-coupled receptors, which comprise four receptors (i.e., PAR-1, PAR-2, PAR-3, and PAR-4) activated by various proteases. Both PAR-1 and PAR-2 are over-expressed on GC cells and their activation triggers and/or amplifies intracellular pathways, which sustain gastric carcinogenesis. There is also evidence that expression of either PAR-1 or PAR-2 correlates with depth of wall invasion and metastatic dissemination and inversely with the overall survival of patients. Consistently, data emerging from experimental models of GC suggest that both these receptors can be important targets for therapeutic interventions in GC patients. In contrast, PAR-4 levels are down-regulated in GC and correlate inversely with the aggressiveness of GC, thus suggesting a negative role of this receptor in the control of GC. In this article we review the available data on the expression and role of PARs in GC and discuss whether manipulation of PAR-driven signals may be useful for interfering with GC cell behavior. PMID:25232234

Evaluation of Methods to Increase Light Under Ferry Terminals

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

Blanton, Susan L.; Thom, Ronald M.; Borde, Amy B.

2002-01-02

To address concerns of resource agencies about the potential impacts of ferry terminal expansion on valuable habitat functions and resource use of nearshore areas, the Pacific Northwest National Laboratory (PNNL), in partnership with the Washington State Department of Transportation (WSDOT), conducted field trials with off-the-shelf products that promote light passage through dock structures. These products included a SunTunnel, deck prisms, and a metal halide greenhouse light. Light measurements (photosynthetically active radiation, PAR) were also recorded beneath glass blocks and a metal grating installed at Clinton Ferry Terminal on Whidbey Island, WA. A review of other studies measuring the effects ofmore » dock shading and alternate dock materials was conducted. PAR measurements from this study were related to minimum requirements for eelgrass Zostera marina photosynthesis and to the known maximum photosynthetic ?saturation? rate for Z. marina. We also related PAR measurements to what we know about light effects on juvenile salmonid feeding and passage under overwater structures. Of the light technologies tested, the metal halide light, SunTunnel, glass blocks, and grating potentially provide enough light for eelgrass growth underneath a ferry terminal with similar construction to the Clinton Ferry Terminal. All of these technologies would potentially provide adequate light under conditions where eelgrass is located at its upper depth limit and a dock is close to the water surface. Light levels needed to allow fish to feed and to form schools are low (~ 1-2 mmol/m2/s), and much less than those required for photosynthesis. Our research indicates that installing any of the tested light products would likely maintain light levels under the dock above those required for active feeding by juvenile salmonids.« less

PAR-2 mediates increased inflammatory cell adhesion and neointima formation following vascular injury in the mouse.

PubMed

Tennant, Gail M; Wadsworth, Roger M; Kennedy, Simon

2008-05-01

Activation of PAR-2 in the vasculature affects vascular tone and adhesion of leukocytes to the endothelium. Since adhesion of leukocytes is increased following vascular injury and is important in determining the extent of neointima formation, we hypothesised that mice lacking PAR-2 may have reduced neointima formation following vascular injury. PAR-2 activating peptides and trypsin induced endothelium-dependent relaxation of mouse carotid artery which was absent in the knockout mouse. Lack of a PAR-2 receptor did not affect lymphocyte adhesion under basal conditions, but reduced the contractile response produced by lymphocytes. Twenty-eight days after denuding injury, vessel contraction to lymphocytes was reduced in both strains while lymphocyte adhesion was significantly greater in PAR-2(+/+) mice compared to the PAR-2 knockout mice. Neointimal area was markedly reduced in the PAR-2 knockout mouse. Our data show that PAR-2 modulates inflammatory cell adhesion when stimulated and in mice lacking the PAR-2 receptor, adhesion to injured vessels is reduced with a consequent reduction in neointima formation.

The polarity protein Par3 regulates APP trafficking and processing through the endocytic adaptor protein Numb.

PubMed

Sun, Miao; Asghar, Suwaiba Z; Zhang, Huaye

2016-09-01

The processing of amyloid precursor protein (APP) into β-amyloid peptide (Aβ) is a key step in the pathogenesis of Alzheimer's disease (AD), and trafficking dysregulations of APP and its secretases contribute significantly to altered APP processing. Here we show that the cell polarity protein Par3 plays an important role in APP processing and trafficking. We found that the expression of full length Par3 is significantly decreased in AD patients. Overexpression of Par3 promotes non-amyloidogenic APP processing, while depletion of Par3 induces intracellular accumulation of Aβ. We further show that Par3 functions by regulating APP trafficking. Loss of Par3 decreases surface expression of APP by targeting APP to the late endosome/lysosome pathway. Finally, we show that the effects of Par3 are mediated through the endocytic adaptor protein Numb, and Par3 functions by interfering with the interaction between Numb and APP. Together, our studies show a novel role for Par3 in regulating APP processing and trafficking. Copyright © 2016 Elsevier Inc. All rights reserved.

Heat shock proteins HSP70 and MRJ cooperatively regulate cell adhesion and migration through urokinase receptor.

PubMed

Lin, Yuli; Peng, Nana; Zhuang, Hongqin; Zhang, Di; Wang, Yao; Hua, Zi-Chun

2014-08-30

The urokinase-type plasminogen activator receptor (uPAR) is an important regulator of ECM proteolysis, cell-ECM interactions and cell signaling. uPAR and heat shock proteins HSP70 and MRJ (DNAJB6) have been implicated in tumor growth and metastasis. We have reported recently that MRJ (DNAJB6, a heat shock protein) can interact with uPAR and enhance cell adhesion. Here, we identified another heat shock protein HSP70 as a novel uPAR-interacting protein. We performed co-immunoprecipitation in human embryonic kidney (HEK) 293 and colon cancer HCT116 cells as well as immunofluorence assays in HEK293 cells stably transfected with uPAR to investigate the association of suPAR with HSP70/MRJ. To understand the biological functions of the triple complex of suPAR/HSP70/MRJ, we determined whether HSP70 and/or MRJ regulated uPAR-mediated cell invasion, migration, adhesion to vitronectin and MAPK pathway in two pair of human tumor cells (uPAR negative HEK293 cells vs HEK293 cells stably transfected with uPAR and HCT116 cells stably transfected with antisense-uPAR vs HCT116 mock cells transfected with vector only) using transwell assay, wound healing assay, quantitative RT-PCR analyzing mmp2 and mmp9 transcription levels, cell adhesion assay and Western blotting assay. HSP70 and MRJ formed a triple complex with uPAR and over-expression of MRJ enhanced the interaction between HSP70 and uPAR, while knockdown of MRJ decreased soluble uPAR in HCT116 cells (P < 0.05) and reduced the formation of the triple complex, suggesting that MRJ may act as an uPAR-specific adaptor protein to link uPAR to HSP70. Further experiments showed that knockdown of HSP70 and/or MRJ by siRNA inhibited uPAR-mediated cell adhesion to vitronectin as well as suppressed cell invasion and migration. Knockdown of HSP70 and/or MRJ inhibited expression of invasion related genes mmp2 and mmp9. Finally, HSP70 and/or MRJ up-regulated phosphorylation levels of ERK1/2 and FAK suggesting MAPK pathway was involved. All the biological function experiments in cell level showed an additive effect when HSP70 and MRJ were regulated simultaneously indicating their collaborated regulation effects on uPAR. These findings may offer a novel insight into the interactions between uPAR and HSP70/MRJ and their functions in cell adhesion and migration may provide more understanding of the roles in regulating cancer metastasis.

Population attributable risks of oral cavity cancer to behavioral and medical risk factors in France: results of a large population-based case-control study, the ICARE study.

PubMed

Radoï, Loredana; Menvielle, Gwenn; Cyr, Diane; Lapôtre-Ledoux, Bénédicte; Stücker, Isabelle; Luce, Danièle

2015-10-31

Population attributable risks (PARs) are useful tool to estimate the burden of risk factors in cancer incidence. Few studies estimated the PARs of oral cavity cancer to tobacco smoking alone, alcohol drinking alone and their joint consumption but none performed analysis stratified by subsite, gender or age. Among the suspected risk factors of oral cavity cancer, only PAR to a family history of head and neck cancer was reported in two studies. The purpose of this study was to estimate in France the PARs of oral cavity cancer to several recognized and suspected risk factors, overall and by subsite, gender and age. We analysed data from 689 oral cavity cancer cases and 3481 controls included in a population-based case-control study, the ICARE study. Unconditional logistic regression models were used to estimate odds ratios (ORs), PARs and 95% confidence intervals (95% CI). The PARs were 0.3% (95% CI -3.9%; +3.9%) for alcohol alone, 12.7% (6.9%-18.0%) for tobacco alone and 69.9% (64.4%-74.7%) for their joint consumption. PAR to combined alcohol and tobacco consumption was 74% (66.5%-79.9%) in men and 45.4% (32.7%-55.6%) in women. Among suspected risk factors, body mass index 2 years before the interview <25 kg.m(-2), never tea drinking and family history of head and neck cancer explained 35.3% (25.7%-43.6%), 30.3% (14.4%-43.3%) and 5.8% (0.6%-10.8%) of cancer burden, respectively. About 93% (88.3%-95.6%) of oral cavity cancers were explained by all risk factors, 94.3% (88.4%-97.2%) in men and only 74.1% (47.0%-87.3%) in women. Our study emphasizes the role of combined tobacco and alcohol consumption in the oral cavity cancer burden in France and gives an indication of the proportion of cases attributable to other risk factors. Most of oral cavity cancers are attributable to concurrent smoking and drinking and would be potentially preventable through smoking or drinking cessation. If the majority of cases are explained by recognized or suspected risk factors in men, a substantial number of cancers in women are probably due to still unexplored factors that remain to be clarified by future studies.

Efficacy, safety and mechanism of HP-β-CD-PEI polymers as absorption enhancers on the intestinal absorption of poorly absorbable drugs in rats.

PubMed

Zhang, Hailong; Huang, Xiaoyan; Zhang, Yongjing; Gao, Yang

2017-03-01

Oral bioavailability of some hydrophilic therapeutic macromolecules was very poor, thus leading to their limited application in clinic. To investigate the efficacy, safety and mechanism of HP-β-CD-PEI polymers on the intestinal absorption of some poorly absorbable drugs in rats. Effects of HP-β-CD-PEI polymers on the intestinal absorptions of drugs were investigated by an in situ closed loop method in rats. The safety of HP-β-CD-PEI polymer was evaluated by measurement of lactate dehydrogenase (LDH) activity and amount of protein released from rat intestinal perfusate. The absorption enhancing mechanisms were explored by the measurement of zeta potential, transepithelial electrical resistance (TEER) and in vitro transport of FD4 (a paracellular marker) across rat intestinal membranes, respectively. HP-β-CD-PEI polymers, especially HP-β-CD-PEI 1800 , demonstrated excellent absorption enhancing effects on drug absorption in a concentration-dependent manner and the enhancing effect was more efficient in the small intestine than that in the large intestine. Five percent (w/v) HP-β-CD-PEI 1800 obviously decreased the TEER, accompanied with increase in the intestinal transport of FD4, indicating that absorption enhancing actions of HP-β-CD-PEI polymers were possibly performed by loosening tight junctions of intestinal epithelium cells, thereby increasing drug permeation via a paracellular pathway. A good liner relationship between absorption enhancing effects of HP-β-CD-PEI polymers and their zeta potentials suggested the contribution of positive charge on the surface of these polymers to their absorption enhancing effects. HP-β-CD-PEI polymers might be potential and safe absorption enhancers for improving oral delivery of poorly absorbable macromolecules including peptides and proteins.

Proteinase-activated receptor 2 modulates OA-related pain, cartilage and bone pathology.

PubMed

Huesa, Carmen; Ortiz, Ana C; Dunning, Lynette; McGavin, Laura; Bennett, Louise; McIntosh, Kathryn; Crilly, Anne; Kurowska-Stolarska, Mariola; Plevin, Robin; van 't Hof, Rob J; Rowan, Andrew D; McInnes, Iain B; Goodyear, Carl S; Lockhart, John C; Ferrell, William R

2016-11-01

Proteinase-activated receptor 2 (PAR2) deficiency protects against cartilage degradation in experimental osteoarthritis (OA). The wider impact of this pathway upon OA-associated pathologies such as osteophyte formation and pain is unknown. Herein, we investigated early temporal bone and cartilage changes in experimental OA in order to further elucidate the role of PAR2 in OA pathogenesis. OA was induced in wild-type (WT) and PAR2-deficient (PAR2 -/- ) mice by destabilisation of the medial meniscus (DMM). Inflammation, cartilage degradation and bone changes were monitored using histology and microCT. In gene rescue experiments, PAR2 -/- mice were intra-articularly injected with human PAR2 (hPAR2)-expressing adenovirus. Dynamic weight bearing was used as a surrogate of OA-related pain. Osteophytes formed within 7 days post-DMM in WT mice but osteosclerosis was only evident from 14 days post induction. Importantly, PAR2 was expressed in the proliferative/hypertrophic chondrocytes present within osteophytes. In PAR2 -/- mice, osteophytes developed significantly less frequently but, when present, were smaller and of greater density; no osteosclerosis was observed in these mice up to day 28. The pattern of weight bearing was altered in PAR2 -/- mice, suggesting reduced pain perception. The expression of hPAR2 in PAR2 -/- mice recapitulated osteophyte formation and cartilage damage similar to that observed in WT mice. However, osteosclerosis was absent, consistent with lack of hPAR2 expression in subchondral bone. This study clearly demonstrates PAR2 plays a critical role, via chondrocytes, in osteophyte development and subchondral bone changes, which occur prior to PAR2-mediated cartilage damage. The latter likely occurs independently of OA-related bone changes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Gravitational lensing in observational cosmology

NASA Astrophysics Data System (ADS)

Nottale, L.

This paper reviews some previous theoretical and observational results concerning the various effects of gravitational lensing, and also presents still unpublished results in this field. The theoretical section deals with the Optical Scalar Equation (OSE) approach. We recall the form of these equations, which relate the deformations of the cross sectional area of a light beam to the material and energetic distribution it encounters, via the two basic contributions to lensing, the matter or Ricci term and the shear term. The introduction of a new distance, the optical distance, allows to write the OSE in a simplified way from which new solutions are easily derived. We demonstrate here that a general form may be obtained for the amplification formula in the exact relativistic treatment, provided the Universe is assumed to be Friedmannian in the mean. New results are also presented concerning the probability distribution of amplifications, the relation from matter term to shear terms (the first ones give the mean of the second ones) and the problem of energy conservation. We recall how our method let to an analytical formula yielding the amplification by any number of lenses placed anywhere along the line of sight and present new general solutions for lensing by large scale density inhomogeneities. The gravitational redshift effects are also considered, either due to the crossing by photons of inhomogeneities, or intrinsic to them ; generalized solutions to the last problem are given. Some observational evidence concerning various lensing effects, either statistical or applying to individual sources, are considered. We first recall how the dependence of the amplification formula on the various physical parameters points towards the optimisation of lensing by very rich clusters of galaxies lying at redshifts around 0.7, which may give rise to very large amplifications for reasonable values of the density parameter. Recent results concerning a statistical effect of amplification of Brightest Cluster Galaxies by foreground clusters are analysed, including the discussion of a selection effect precisely due to gravitational luminosity amplification. It results in an artificial increase of the deceleration parameter of the Universe measured from the Hubble diagram of these objects. We recall our proposal that the sample of distant 3C radiogalaxies of redshift > 1 is strongly perturbed by lensing effects, mostly by foreground clusters of galaxies (i.e. only the luminosity is changed without image multiplication), but also for some objects by galaxies, producing gravitational mirages. The case of 3C324, for which definite evidence for multiple imaging has been recently obtained, is described, including detailed modelling of the lensing configuration. We present a highly significant statistical effect of lensing on absorption line QSOs due to matter lying at the absorption redshifts. Microlensing is also considered, and we recall our recent proposal that the variability of some among the OVV QSOs turning to BL Lac at maximum brightness, like the eruptive object 0846 +51W1, is a consequence of microlensing by stars or compact objects constituting foreground galaxy halos. Finally, discrepant redshift associations are considered. We recall how the case of anomalous quintets of galaxies have been explained by the gravitational lensing effects of quartets halos on background galaxies. Then we present evidence that the Arp QSO-galaxy associations may be the result of the combined lensing effects of several superposed galaxies, groups and clusters. Cet article présente une revue de certains résultats théoriques et observationnels concernant les divers effets de lentille gravitationnelle, complétée par des résultats nouveaux non encore publiés. Dans la partie théorique, nous considérons essentiellement l'approche relativiste employant les équations scalaires optiques. La forme de ces équations est rappelée : elles relient les diverses déformations subies par la section d'un faisceau lumineux au cours de sa propagation, à la distribution matérielle et énergétique qu'il rencontre sur son trajet entre la source et l'observateur. Les deux contributions aux effets d'optique apparaissant dans ces équations (et leurs solutions) sont les termes de matière et les termes de cisaillement. Nous montrons comment une nouvelle distance peut être introduite, la distance optique, en fonction de laquelle les équations se simplifient et de nouvelles solutions analytiques peuvent être établies. En particulier, nous démontrons que la formule d'amplification gravitationnelle peut s'écrire sous une forme très générale sous la simple hypothèse que l'Univers est en moyenne de type Friedmann-Robertson-Walker. De nouveaux résultats sont aussi présentés concernant la distribution de probabilité des amplifications, les rapports entre termes de matière et termes de cisaillement (les premiers donnant la moyenne des seconds), et le problème de la conservation de l'énergie. Nous rappelons comment une formule analytique peut être obtenue pour des amplifications multiples et présentons des solutions nouvelles au problème de l'amplification par des hétérogénéités à très grande échelle. Enfin, les effets de décalages spectraux gravitationnels sont aussi considérés, qu'ils soient dus à des effets de traversée d'excès de densité, ou intrinsèques à ceux-ci ; dans ce dernier cas, une généralisation de solutions déjà connues est proposée. On considère ensuite le problème de la mise en évidence observationnelle des divers effets d'optique gravitationnelle, qu'ils soient de nature statistique ou qu'ils concernent des objets individuels. A la suite d'une analyse décrivant la dépendance de la formule d'amplification en fonction des différents paramètres y intervenant, nous insistons tout particulièrement sur le rôle cosmologique que jouent probablement les amas de galaxies très riches de décalages spectraux autour de 0,7 qui peuvent donner lieu à des amplifications quasi-infinies. La mise en évidence récente d'un effet statistique d'amplification par des amas d'avant-plan sur les galaxies les plus brillantes des amas est rappelée, ainsi que celle d'un important effet de sélection observationnel, précisément dû aux amplifications, qui augmente artificiellement la valeur de q0 mesurée à partir du diagramme de Hubble. L'extrapolation de cet effet à des objets plus lointains nous a conduit à proposer que les radiogalaxies lointaines du catalogue 3C de z < 1 étaient fortement affectées par les effets de lentille gravitationnelle, essentiellement par les amas (qui les amplifient la plupart du temps sans multiplication d'image), mais aussi dans certains cas par des galaxies qui peuvent alors provoquer des effets de mirage. Le cas de 3C324, pour lequel des preuves observationelles de multiplication d'image ont été récemment obtenues, est analysé en particulier ; un modèle détaillé en est présenté. Un autre effet statistique récemment démontré concerne les quasars à raies d'absorption, dont la luminosité est fortement corrélée à l'amplification prédite par de la matière située aux décalages spectraux d'absorption. On considère également les effets de microlentille : nous rappelons notre proposition récente que la variabilité de certains OVVs tels que le BL Lac éruptif 0846 + 51W1 est une conséquence du passage d'étoiles ou d'objets compacts du halo de galaxies intervenantes devant les régions centrales d'un quasar. Le lien entre effets d'optique gravitationnelle et associations de décalages spectraux discordants est évoqué. Le cas des quintets de galaxies discordant a été récemment expliqué par les effets (amplification, agrandissement, changement de densité superficielle d'objets lointains) des halos de groupes compacts de galaxies. Nous démontrons pour finir que les associations QSOsgalaxies de Arp peuvent s'expliquer par les effets de lentille gravitationnelle combinés de plusieurs galaxies, groupes et amas vus en superposition.

Par3L enhances colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway

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

Li, Taiyuan; Liu, Dongning; Lei, Xiong

Partitioning defective 3-like protein (Par3L) is a recently identified cell polarity protein that plays an important role in mammary stem cell maintenance. Previously, we showed that high expression of Par3L is associated with poor survival in malignant colorectal cancer (CRC), but the underlying mechanism remained unknown. To this end, we established a Par3L knockout colorectal cancer cell line using the CRISPR/Cas system. Interestingly, reduced proliferation, enhanced cell death and caspase-3 activation were observed in Par3L knockout (KO) cells as compared with wildtype (WT) cells. Consistent with previous studies, we showed that Par3L interacts with a tumor suppressor protein liver kinasemore » B1 (Lkb1). Moreover, Par3L depletion resulted in abnormal activation of Lkb1/AMPK signaling cascade. Knockdown of Lkb1 in these cells could significantly reduce AMPK activity and partially rescue cell death caused by Par3L knockdown. Furthermore, we showed that Par3L KO cells were more sensitive to chemotherapies and irradiation. Together, these results suggest that Par3L is essential for colorectal cancer cell survival by inhibiting Lkb1/AMPK signaling pathway, and is a putative therapeutic target for CRC. - Highlights: • Par3L knockout using the CRISPR/Cas system induces apoptosis in colorectal cancer cells. • Par3L interacts with Lkb1 and regulates the activity of AMPK signaling cascade. • Par3L knockout cells are more sensitive to treatment of different chemotherapy drugs and irradiation.« less

Synthesis and characterization of an 111In-labeled peptide for the in vivo localization of human cancers expressing the urokinase-type plasminogen activator receptor (uPAR)

PubMed Central

Liu, Dijie; Overbey, Douglas; Watkinson, Lisa; Giblin, Michael F.

2009-01-01

This study describes the synthesis and preliminary biologic evaluation of an 111Inlabeled peptide antagonist of the urokinase-type plasminogen activator receptor (uPAR) as a potential probe for assessing metastatic potential of human breast cancer in vivo. The peptide (NAc-dD-CHA-F-dS-dR-Y-L-W-S-βAla)2-K-K(DOTA)-NH2 was synthesized and conjugated with the DOTA chelating moiety via conventional Solid-Phase Peptide Synthesis (SPPS), purified by reversed-phase HPLC, and characterized by MALDI-TOF MS and receptor binding assay. In vitro receptor binding studies demonstrated an IC50 of 240 ± 125 nM for the peptide, compared with IC50’s of 0.44 ± 0.02 and 0.75 ± 0.01 nM for the amino terminal fragment (ATF) of the urokinase-type plasminogen activator (uPA) and full-length uPA, respectively. In vivo biodistribution studies were carried out using SCID mice bearing MDA-MB-231 human breast cancer xenografts. Biodistribution data was collected at 1, 4, and 24 hr post-injection of 111In-DOTA-peptide, and compared with data obtained using a scrambled control peptide, as well as with data obtained using wild-type ATF radiolabeled with I-125. Biodistribution studies showed rapid elimination of the 111In-labeled peptide from the blood pool, with 0.12 ± 0.06% ID/g remaining in blood at 4 hr pi. Elimination was seen primarily via the renal/urinary route, with 83.9 ± 2.2%ID in the urine at the same timepoint. Tumor uptake at this time was 0.53 ± 0.11%ID/g, resulting in tumor: blood and tumor: muscle ratios of 4.2 and 9.4, respectively. Uptake in tumor was significantly higher than that obtained using a scrambled control peptide that showed no specific binding to uPAR (p < 0.05). In vitro and ex vivo results both suggested that the magnitude of tumor-specific binding was reduced in this model by endogenous expression of uPA. The results indicate that radiolabeled peptide uPAR antagonists may find application in the imaging and therapy of uPAR-expressing breast cancers in vivo. PMID:19354275

A three-dimensional ParF meshwork assembles through the nucleoid to mediate plasmid segregation.

PubMed

McLeod, Brett N; Allison-Gamble, Gina E; Barge, Madhuri T; Tonthat, Nam K; Schumacher, Maria A; Hayes, Finbarr; Barillà, Daniela

2017-04-07

Genome segregation is a fundamental step in the life cycle of every cell. Most bacteria rely on dedicated DNA partition proteins to actively segregate chromosomes and low copy-number plasmids. Here, by employing super resolution microscopy, we establish that the ParF DNA partition protein of the ParA family assembles into a three-dimensional meshwork that uses the nucleoid as a scaffold and periodically shuttles between its poles. Whereas ParF specifies the territory for plasmid trafficking, the ParG partner protein dictates the tempo of ParF assembly cycles and plasmid segregation events by stimulating ParF adenosine triphosphate hydrolysis. Mutants in which this ParG temporal regulation is ablated show partition deficient phenotypes as a result of either altered ParF structure or dynamics and indicate that ParF nucleoid localization and dynamic relocation, although necessary, are not sufficient per se to ensure plasmid segregation. We propose a Venus flytrap model that merges the concepts of ParA polymerization and gradient formation and speculate that a transient, dynamic network of intersecting polymers that branches into the nucleoid interior is a widespread mechanism to distribute sizeable cargos within prokaryotic cells. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Evidence that compatibility of closely related replicons in Clostridium perfringens depends on linkage to parMRC-like partitioning systems of different subfamilies.

PubMed

Watts, Thomas D; Johanesen, Priscilla A; Lyras, Dena; Rood, Julian I; Adams, Vicki

2017-05-01

Clostridium perfringens produces an extensive repertoire of toxins and extracellular enzymes, many of which are intimately involved in the progression of disease and are encoded by genes on conjugative plasmids. In addition, many C. perfringens strains can carry up to five of these conjugative toxin or antimicrobial resistance plasmids, each of which has a similar 35kb backbone. This conserved backbone includes the tcp conjugation locus and the central control region (CCR), which encodes genes involved in plasmid regulation, replication and partitioning, including a parMRC partitioning locus. Most conjugative plasmids in C. perfringens have a conserved replication protein, raising questions as to how multiple, closely related plasmids are maintained within a single strain. Bioinformatics analysis has highlighted the presence of at least 10 different parMRC partitioning system families (parMRC A-J ) in these plasmids, with differences in amino acid sequence identity between each ParM family ranging from 15% to 54%. No two plasmids that encode genes belonging to the same partitioning family have been observed in a single strain, suggesting that these families represent the basis for plasmid incompatibility. In an attempt to validate the proposed parMRC incompatibility groups, genetically marked C. perfringens plasmids encoding identical parMRC C or parMRC D homologues or different combinations of parMRC A , parMRC C and parMRC D family homologues were introduced into a single strain via conjugation. The stability of each plasmid was determined using an incompatibility assay in which the plasmid profile of each strain was monitored over the course of two days in the absence of direct selection. The results showed that plasmids with identical parMRC C or parMRC D homologues were incompatible and could not coexist in the absence of external selection. By contrast, plasmids that encoded different parMRC homologues were compatible and could coexist in the same cell in the absence of selection, with the exception of strains housing parMRC C and parMRC D combinations, which showed a minor incompatibility phenotype. In conclusion, we have provided the first direct evidence of plasmid incompatibility in Clostridium spp. and have shown experimentally that the compatibility of conjugative C. perfringens plasmids correlates with the presence of parMRC-like partitioning systems of different phylogenetic subfamilies. Copyright © 2017 Elsevier Inc. All rights reserved.

Coral Skeletons Defend against Ultraviolet Radiation

PubMed Central

Reef, Ruth; Kaniewska, Paulina; Hoegh-Guldberg, Ove

2009-01-01

Background Many coral reef organisms are photosynthetic or have evolved in tight symbiosis with photosynthetic symbionts. As such, the tissues of reef organisms are often exposed to intense solar radiation in clear tropical waters and have adapted to trap and harness photosynthetically active radiation (PAR). High levels of ultraviolet radiation (UVR) associated with sunlight, however, represent a potential problem in terms of tissue damage. Methodology/Principal Findings By measuring UVR and PAR reflectance from intact and ground bare coral skeletons we show that the property of calcium carbonate skeletons to absorb downwelling UVR to a significant extent, while reflecting PAR back to the overlying tissue, has biological advantages. We placed cnidarians on top of bare skeletons and a UVR reflective substrate and showed that under ambient UVR levels, UVR transmitted through the tissues of cnidarians placed on top of bare skeletons were four times lower compared to their counterparts placed on a UVR reflective white substrate. In accordance with the lower levels of UVR measured in cnidarians on top of coral skeletons, a similar drop in UVR damage to their DNA was detected. The skeletons emitted absorbed UVR as yellow fluorescence, which allows for safe dissipation of the otherwise harmful radiation. Conclusions/Significance Our study presents a novel defensive role for coral skeletons and reveals that the strong UVR absorbance by the skeleton can contribute to the ability of corals, and potentially other calcifiers, to thrive under UVR levels that are detrimental to most marine life. PMID:19946361

An Implementation in Pascal: Translation of Prolog into Pascal.

DTIC Science & Technology

1985-06-01

for i:=1 to px do begin ifr (proc .i..relativity=O) then continue; if proc .. ) .ptype=6) hen continue;if (proc (...abegin<>O) then continue; passname...forj:=reitorn do if (j0) then continue; if (par (.>) ppe <>1) then continue; if (par .. .namie<>par(.i.).name) parle nO ype:par C.’ ntype; par Inblnd

ParC subunit of DNA topoisomerase IV of Streptococcus pneumoniae is a primary target of fluoroquinolones and cooperates with DNA gyrase A subunit in forming resistance phenotype.

PubMed Central

Muñoz, R; De La Campa, A G

1996-01-01

The genes encoding the ParC and ParE subunits of topoisomerase IV of Streptococcus pneumoniae, together with the region encoding amino acids 46 to 172 (residue numbers are as in Escherichia coli) of the pneumococcal GyrA subunit, were partially characterized. The gyrA gene maps to a physical location distant from the gyrB and parC loci on the chromosome, whereas parC is closely linked to parE. Ciprofloxacin-resistant (Cpr) clinical isolates of S. pneumoniae had mutations affecting amino acid residues of the quinolone resistance-determining region of ParC (low-level Cpr) or in both quinolone resistance-determining regions of ParC and GyrA (high-level Cpr). Mutations were found in residue positions equivalent to the serine at position 83 and the aspartic acid at position 87 of the E. coli GyrA subunit. Transformation experiments suggest that ParC is the primary target of ciprofloxacin. Mutation in parC appears to be a prerequisite before mutations in gyrA can influence resistance levels. PMID:8891124

Condensin promotes the juxtaposition of DNA flanking its loading site in Bacillus subtilis

PubMed Central

Wang, Xindan; Le, Tung B.K.; Lajoie, Bryan R.; Dekker, Job; Laub, Michael T.; Rudner, David Z.

2015-01-01

SMC condensin complexes play a central role in compacting and resolving replicated chromosomes in virtually all organisms, yet how they accomplish this remains elusive. In Bacillus subtilis, condensin is loaded at centromeric parS sites, where it encircles DNA and individualizes newly replicated origins. Using chromosome conformation capture and cytological assays, we show that condensin recruitment to origin-proximal parS sites is required for the juxtaposition of the two chromosome arms. Recruitment to ectopic parS sites promotes alignment of large tracks of DNA flanking these sites. Importantly, insertion of parS sites on opposing arms indicates that these “zip-up” interactions only occur between adjacent DNA segments. Collectively, our data suggest that condensin resolves replicated origins by promoting the juxtaposition of DNA flanking parS sites, drawing sister origins in on themselves and away from each other. These results are consistent with a model in which condensin encircles the DNA flanking its loading site and then slides down, tethering the two arms together. Lengthwise condensation via loop extrusion could provide a generalizable mechanism by which condensin complexes act dynamically to individualize origins in B. subtilis and, when loaded along eukaryotic chromosomes, resolve them during mitosis. PMID:26253537

Protease-activated receptor 2 in dorsal root ganglion contributes to peripheral sensitization of bone cancer pain.

PubMed

Liu, S; Liu, Y-P; Yue, D-M; Liu, G-J

2014-03-01

Treating bone cancer pain continues to be a major clinical challenge, and the underlying mechanisms of bone cancer pain remain elusive. Protease-activated receptor 2 (PAR2) has been reported to be involved in neurogenic inflammation, nociceptive pain and hyperalgesia. Here, we investigated the role of PAR2 in bone cancer pain development. Expression of PAR2, mechanical allodynia, thermal hyperalgesia and neurochemical alterations induced by bone cancer pain were analysed in male, adult C3H/HeJ mice with tumour cell implantation (TCI). To investigate the contribution of PAR2 to bone cancer pain, PAR2 antagonist peptide and PAR2 knockout mice were used. TCI produced bone cancer-related pain behaviours. Production and persistence of these pain behaviours were well correlated with TCI-induced up-regulation of PAR2 in sciatic nerve and dorsal root ganglia (DRG). PAR2 knockout and spinal administration of PAR2 antagonist peptide prevented and/or reversed bone cancer-related pain behaviours and associated neurochemical changes in DRG and dorsal horn (DH). TCI also induced proteases release in tumour-bearing tibia, sciatic nerve and DRG. Plantar injection of supernatant from sarcoma cells induced PAR2 up-regulation and intracellular calcium [Ca(2+) ]i increase in DRG, and calcitonin gene-related peptide accumulation in DH, as well as significant thermal and mechanical hyperalgesia, which were all in PAR2-dependent manners. These findings suggest that PAR2 may be a key mediator for peripheral sensitization of bone cancer pain. Inhibiting PAR2 activation, especially during the early phase, may be a new therapy for preventing/suppressing development of bone cancer pain. © 2013 European Pain Federation - EFIC®

mTORC2 activation is regulated by the urokinase receptor (uPAR) in bladder cancer.

PubMed

Hau, Andrew M; Leivo, Mariah Z; Gilder, Andrew S; Hu, Jing-Jing; Gonias, Steven L; Hansel, Donna E

2017-01-01

Mammalian target of rapamycin complex 2 (mTORC2) has been identified as a major regulator of bladder cancer cell migration and invasion. Upstream pathways that mediate mTORC2 activation remain poorly defined. Urokinase-type plasminogen activator receptor (uPAR) is a GPI-anchored membrane protein and known activator of cell-signaling. We identified increased uPAR expression in 94% of invasive human bladder cancers and in 54-71% of non-invasive bladder cancers, depending on grade. Normal urothelium was uPAR-immunonegative. Analysis of publicly available datasets identified uPAR gene amplification or mRNA upregulation in a subset of bladder cancer patients with reduced overall survival. Using biochemical approaches, we showed that uPAR activates mTORC2 in bladder cancer cells. Highly invasive bladder cancer cell lines, including T24, J82 and UM-UC-3 cells, showed increased uPAR mRNA expression and protein levels compared with the less aggressive cell lines, UROtsa and RT4. uPAR gene-silencing significantly reduced phosphorylation of Serine-473 in Akt, an mTORC2 target. uPAR gene-silencing also reduced bladder cancer cell migration and Matrigel invasion. S473 phosphorylation was observed by immunohistochemistry in human bladder cancers only when the tumors expressed high levels of uPAR. S473 phosphorylation was not controlled by uPAR in bladder cancer cell lines that are PTEN-negative; however, this result probably did not reflect altered mTORC2 regulation. Instead, PTEN deficiency de-repressed alternative kinases that phosphorylate S473. Our results suggest that uPAR and mTORC2 are components of a single cell-signaling pathway. Targeting uPAR or mTORC2 may be beneficial in patients with bladder cancer. Copyright © 2016. Published by Elsevier Inc.

Proteinase-activated receptor-4 evoked colorectal analgesia in mice: an endogenously activated feed-back loop in visceral inflammatory pain.

PubMed

Annaházi, A; Dabek, M; Gecse, K; Salvador-Cartier, C; Polizzi, A; Rosztóczy, A; Róka, R; Theodorou, V; Wittmann, T; Bueno, L; Eutamene, H

2012-01-01

Activation of proteinase-activated receptor-4 (PAR-4) from the colonic lumen has an antinociceptive effect to colorectal distension (CRD) in mice in basal conditions. We aimed to determine the functional localization of the responsible receptors and to test their role in two different hyperalgesia models. Mice received PAR-4 activating peptide (PAR-4-AP, AYPGKF-NH(2)) or vehicle intraperitoneally (IP), and abdominal EMG response to CRD was measured. The next group received PAR-4-AP intracolonically (IC) with or without 2,4,6-triaminopyrimidine, a chemical tight junction blocker, before CRD. The SCID mice were used to test the role of lymphocytes in the antihyperalgesic effect. The effects of PAR-4-AP and PAR-4-antagonist (P4pal-10) were evaluated in water avoidance stress (WAS) model and low grade 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis. Spinal Fos protein expression was visualized by immunohistochemistry. The antinociceptive effect of PAR-4-AP disappeared when was administrered IP, or with the blockade of colonic epithelial tight junctions, suggesting that PAR-4-AP needs to reach directly the nerve terminals in the colon. The CRD-induced spinal Fos overexpression was reduced by 43% by PAR-4-AP. The PAR-4-AP was antihyperalgesic in both hyperalgesia models and in mice with impaired lymphocytes. The PAR-4-antagonist significantly increased the TNBS, but not the WAS-induced colonic hyperalgesia. The antinociceptive effect of PAR-4-AP depends on its penetration to the colonic mucosa. The PAR-4 activation is endogenously involved as a feedback loop to attenuate inflammatory colonic hyperalgesia to CRD. © 2011 Blackwell Publishing Ltd.

Identification of a New Epitope in uPAR as a Target for the Cancer Therapeutic Monoclonal Antibody ATN-658, a Structural Homolog of the uPAR Binding Integrin CD11b (αM)

PubMed Central

Wei, Ying; Donate, Fernando; Juarez, Jose; Parry, Graham; Chen, Liqing; Meehan, Edward J.; Ahn, Richard W.; Ugolkov, Andrey; Dubrovskyi, Oleksii; O'Halloran, Thomas V.; Huang, Mingdong; Mazar, Andrew P.

2014-01-01

The urokinase plasminogen activator receptor (uPAR) plays a role in tumor progression and has been proposed as a target for the treatment of cancer. We recently described the development of a novel humanized monoclonal antibody that targets uPAR and has anti-tumor activity in multiple xenograft animal tumor models. This antibody, ATN-658, does not inhibit ligand binding (i.e. uPA and vitronectin) to uPAR and its mechanism of action remains unclear. As a first step in understanding the anti-tumor activity of ATN-658, we set out to identify the epitope on uPAR to which ATN-658 binds. Guided by comparisons between primate and human uPAR, epitope mapping studies were performed using several orthogonal techniques. Systematic site directed and alanine scanning mutagenesis identified the region of aa 268–275 of uPAR as the epitope for ATN-658. No known function has previously been attributed to this epitope Structural insights into epitope recognition were obtained from structural studies of the Fab fragment of ATN-658 bound to uPAR. The structure shows that the ATN-658 binds to the DIII domain of uPAR, close to the C-terminus of the receptor, corroborating the epitope mapping results. Intriguingly, when bound to uPAR, the complementarity determining region (CDR) regions of ATN-658 closely mimic the binding regions of the integrin CD11b (αM), a previously identified uPAR ligand thought to be involved in leukocyte rolling, migration and complement fixation with no known role in tumor progression of solid tumors. These studies reveal a new functional epitope on uPAR involved in tumor progression and demonstrate a previously unrecognized strategy for the therapeutic targeting of uPAR. PMID:24465541

Autocrine Extra-Pancreatic Trypsin 3 Secretion Promotes Cell Proliferation and Survival in Esophageal Adenocarcinoma

PubMed Central

Han, Song; Lee, Constance W.; Trevino, Jose G.; Hughes, Steven J.; Sarosi, George A.

2013-01-01

Trypsin or Tumor associated trypsin (TAT) activation of Protease-activated receptor 2 (PAR-2) promotes tumor cell proliferation in gastrointestinal cancers. The role of the trypsin/PAR-2 network in esophageal adenocarcinoma (EA) development has not yet been investigated. The aim of this study is to investigate the role of trypsin/PAR-2 activation in EA tumorogenesis and therapy. We found that esophageal adenocarcinoma cells (EACs) and Barrett’s Metaplasia (BART) expressed high levels of type 3 extra-pancreatic trypsinogen (PRSS3), a novel type of TAT. Activity of secreted trypsin was detected in cultured media from EA OE19 and OE33 cultures but not from BART culture. Surface PAR-2 expression in BART and EACs was confirmed by both flow cytometry and immunofluorescence. Trypsin induced cell proliferation (∼ 2 fold; P<0.01) in all tested cell lines at a concentration of 10 nM. Inhibition of PAR-2 activity in EACs via the PAR-2 antagonist ENMD (500 µM), anti-PAR2 antibody SAM-11 (2 µg/ml), or siRNA PAR-2 knockdown, reduced cell proliferation and increased apoptosis by up to 4 fold (P<0.01). Trypsin stimulation led to phosphorylation of ERK1/2, suggesting involvement of MAPK pathway in PAR-2 signal transduction. Inhibition of PAR-2 activation or siRNA PAR-2 knockdown in EACs prior to treatment with 5 FU reduced cell viability of EACs by an additional 30% (P<0.01) compared to chemotherapy alone. Our data suggest that extra-pancreatic trypsinogen 3 is produced by EACs and activates PAR-2 in an autocrine manner. PAR-2 activation increases cancer cell proliferation, and promotes cancer cell survival. Targeting the trypsin activated PAR-2 pathway in conjunction with current chemotherapeutic agents may be a viable therapeutic strategy in EA. PMID:24146905

Prohibitin is involved in the activated internalization and degradation of protease-activated receptor 1.

PubMed

Wang, Yan-Jie; Guo, Xiao-Long; Li, Sheng-An; Zhao, Yu-Qi; Liu, Zi-Chao; Lee, Wen-Hui; Xiang, Yang; Zhang, Yun

2014-07-01

The protease-activated receptor 1 (PAR1) is a G-protein-coupled receptor that is irreversibly activated by either thrombin or metalloprotease 1. Due this irrevocable activation, activated internalization and degradation are critical for PAR1 signaling termination. Prohibitin (PHB) is an evolutionarily conserved, ubiquitously expressed, pleiotropic protein and belongs to the stomatin/prohibitin/flotillin/HflK/C (SPFH) domain family. In a previous study, we found that PHB localized on the platelet membrane and participated in PAR1-mediated human platelet aggregation, suggesting that PHB likely regulates the signaling of PAR1. Unfortunately, PHB's exact function in PAR1 internalization and degradation is unclear. In the current study, flow cytometry revealed that PHB expressed on the surface of endothelial cells (HUVECs) but not cancer cells (MDA-MB-231). Further confocal microscopy revealed that PHB dynamically associates with PAR1 in a time-dependent manner following induction with PAR1-activated peptide (PAR1-AP), though differently between HUVECs and MDA-MB-231 cells. Depletion of PHB by RNA interference significantly inhibited PAR1 activated internalization and led to sustained Erk1/2 phosphorylation in the HUVECs; however, a similar effect was not observed in MDA-MB-231 cells. For both the endothelial and cancel cells, PHB repressed PAR1 degradation, while knockdown of PHB led to increased PAR1 degradation, and PHB overexpression inhibited PAR1 degradation. These results suggest that persistent PAR1 signaling due to the absence of membrane PHB and decreased PAR1 degradation caused by the upregulation of intracellular PHB in cancer cells (such as MDA-MB-231 cells) may render cells highly invasive. As such, PHB may be a novel target in future anti-cancer therapeutics, or in more refined cancer malignancy diagnostics. Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetic activity and radial velocity filtering of young Suns: the weak-line T-Tauri stars Par 1379 and Par 2244

NASA Astrophysics Data System (ADS)

Hill, C. A.; Carmona, A.; Donati, J.-F.; Hussain, G. A. J.; Gregory, S. G.; Alencar, S. H. P.; Bouvier, J.; The Matysse Collaboration

2017-12-01

We report the results of our spectropolarimetric monitoring of the weak-line T-Tauri stars (wTTSs) Par 1379 and Par 2244, within the MaTYSSE (Magnetic Topologies of Young Stars and the Survival of close-in giant Exoplanets) programme. Both stars are of a similar mass (1.6 and 1.8 M⊙) and age (1.8 and 1.1 Myr), with Par 1379 hosting an evolved low-mass dusty circumstellar disc, and with Par 2244 showing evidence of a young debris disc. We detect profile distortions and Zeeman signatures in the unpolarized and circularly polarized lines for each star, and have modelled their rotational modulation using tomographic imaging, yielding brightness and magnetic maps. We find that Par 1379 harbours a weak (250 G), mostly poloidal field tilted 65° from the rotation axis. In contrast, Par 2244 hosts a stronger field (860 G) split 3:2 between poloidal and toroidal components, with most of the energy in higher order modes, and with the poloidal component tilted 45° from the rotation axis. Compared to the lower mass wTTSs, V819 Tau and V830 Tau, Par 2244 has a similar field strength, but is much more complex, whereas the much less complex field of Par 1379 is also much weaker than any other mapped wTTS. We find moderate surface differential rotation of 1.4× and 1.8× smaller than Solar, for Par 1379 and Par 2244, respectively. Using our tomographic maps to predict the activity-related radial velocity (RV) jitter, and filter it from the RV curves, we find RV residuals with dispersions of 0.017 and 0.086 km s-1 for Par 1379 and Par 2244, respectively. We find no evidence for close-in giant planets around either star, with 3σ upper limits of 0.56 and 3.54 MJup (at an orbital distance of 0.1 au).

Regulation of protease-activated receptor 1 signaling by the adaptor protein complex 2 and R4 subfamily of regulator of G protein signaling proteins.

PubMed

Chen, Buxin; Siderovski, David P; Neubig, Richard R; Lawson, Mark A; Trejo, Joann

2014-01-17

The G protein-coupled protease-activated receptor 1 (PAR1) is irreversibly proteolytically activated by thrombin. Hence, the precise regulation of PAR1 signaling is important for proper cellular responses. In addition to desensitization, internalization and lysosomal sorting of activated PAR1 are critical for the termination of signaling. Unlike most G protein-coupled receptors, PAR1 internalization is mediated by the clathrin adaptor protein complex 2 (AP-2) and epsin-1, rather than β-arrestins. However, the function of AP-2 and epsin-1 in the regulation of PAR1 signaling is not known. Here, we report that AP-2, and not epsin-1, regulates activated PAR1-stimulated phosphoinositide hydrolysis via two different mechanisms that involve, in part, a subset of R4 subfamily of "regulator of G protein signaling" (RGS) proteins. A significantly greater increase in activated PAR1 signaling was observed in cells depleted of AP-2 using siRNA or in cells expressing a PAR1 (420)AKKAA(424) mutant with defective AP-2 binding. This effect was attributed to AP-2 modulation of PAR1 surface expression and efficiency of G protein coupling. We further found that ectopic expression of R4 subfamily members RGS2, RGS3, RGS4, and RGS5 reduced activated PAR1 wild-type signaling, whereas signaling by the PAR1 AKKAA mutant was minimally affected. Intriguingly, siRNA-mediated depletion analysis revealed a function for RGS5 in the regulation of signaling by the PAR1 wild type but not the AKKAA mutant. Moreover, activation of the PAR1 wild type, and not the AKKAA mutant, induced Gαq association with RGS3 via an AP-2-dependent mechanism. Thus, AP-2 regulates activated PAR1 signaling by altering receptor surface expression and through recruitment of RGS proteins.

Protease-Activated Receptor-2 Is Associated with Terminal Differentiation of Epidermis and Eccrine Sweat Glands

PubMed Central

Shin, Yong-Sup; Kim, Hyung Won; Kim, Chang Deok; Kim, Hyun-Woo; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Ko, Young-Kwon

2015-01-01

Background Protease-activated receptor 2 (PAR-2) participates in various biological activities, including the regulation of epidermal barrier homeostasis, inflammation, pain perception, and melanosome transfer in the skin. Objective To evaluate the basic physiological role of PAR-2 in skin. Methods We investigated PAR-2 expression in human epidermis, skin tumors, and cultured epidermal cells using western blot and immunohistochemical analysis. Additionally, we examined the effect of the PAR-2 agonist, SLIGRL-NH2, on cultured keratinocytes. Results Strong PAR-2 immunoreactivity was observed in the granular layer of normal human skin and the acrosyringium of the eccrine sweat glands. In contrast, weak PAR-2 immunoreactivity was seen in the granular layer of callused skin and in the duct and gland cells of the eccrine sweat glands. Interestingly, PAR-2 immunoreactivity was very weak or absent in the tumor cells of squamous cell carcinoma (SCC) and syringoma. PAR-2 was detected in primary keratinocytes and SV-40T-transformed human epidermal keratinocytes (SV-HEKs), an immortalized keratinocyte cell line, but not in SCC12 cells. SV-HEKs that were fully differentiated following calcium treatment displayed higher PAR-2 expression than undifferentiated SV-HEKs. Treatment of cultured SV-HEKs with PAR-2 agonist increased loricrin and filaggrin expression, a terminal differentiation marker. Conclusion Our data suggest that PAR-2 is associated with terminal differentiation of epidermis and eccrine sweat glands. PMID:26273149

Protease-Activated Receptor-2 Is Associated with Terminal Differentiation of Epidermis and Eccrine Sweat Glands.

PubMed

Shin, Yong-Sup; Kim, Hyung Won; Kim, Chang Deok; Kim, Hyun-Woo; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Ko, Young-Kwon; Lee, Young Ho

2015-08-01

Protease-activated receptor 2 (PAR-2) participates in various biological activities, including the regulation of epidermal barrier homeostasis, inflammation, pain perception, and melanosome transfer in the skin. To evaluate the basic physiological role of PAR-2 in skin. We investigated PAR-2 expression in human epidermis, skin tumors, and cultured epidermal cells using western blot and immunohistochemical analysis. Additionally, we examined the effect of the PAR-2 agonist, SLIGRL-NH2, on cultured keratinocytes. Strong PAR-2 immunoreactivity was observed in the granular layer of normal human skin and the acrosyringium of the eccrine sweat glands. In contrast, weak PAR-2 immunoreactivity was seen in the granular layer of callused skin and in the duct and gland cells of the eccrine sweat glands. Interestingly, PAR-2 immunoreactivity was very weak or absent in the tumor cells of squamous cell carcinoma (SCC) and syringoma. PAR-2 was detected in primary keratinocytes and SV-40T-transformed human epidermal keratinocytes (SV-HEKs), an immortalized keratinocyte cell line, but not in SCC12 cells. SV-HEKs that were fully differentiated following calcium treatment displayed higher PAR-2 expression than undifferentiated SV-HEKs. Treatment of cultured SV-HEKs with PAR-2 agonist increased loricrin and filaggrin expression, a terminal differentiation marker. Our data suggest that PAR-2 is associated with terminal differentiation of epidermis and eccrine sweat glands.

PAR-1 contributes to the innate immune response during viral infection

PubMed Central

Antoniak, Silvio; Owens, A. Phillip; Baunacke, Martin; Williams, Julie C.; Lee, Rebecca D.; Weithäuser, Alice; Sheridan, Patricia A.; Malz, Ronny; Luyendyk, James P.; Esserman, Denise A.; Trejo, JoAnn; Kirchhofer, Daniel; Blaxall, Burns C.; Pawlinski, Rafal; Beck, Melinda A.; Rauch, Ursula; Mackman, Nigel

2013-01-01

Coagulation is a host defense system that limits the spread of pathogens. Coagulation proteases, such as thrombin, also activate cells by cleaving PARs. In this study, we analyzed the role of PAR-1 in coxsackievirus B3–induced (CVB3-induced) myocarditis and influenza A infection. CVB3-infected Par1–/– mice expressed reduced levels of IFN-β and CXCL10 during the early phase of infection compared with Par1+/+ mice that resulted in higher viral loads and cardiac injury at day 8 after infection. Inhibition of either tissue factor or thrombin in WT mice also significantly increased CVB3 levels in the heart and cardiac injury compared with controls. BM transplantation experiments demonstrated that PAR-1 in nonhematopoietic cells protected mice from CVB3 infection. Transgenic mice overexpressing PAR-1 in cardiomyocytes had reduced CVB3-induced myocarditis. We found that cooperative signaling between PAR-1 and TLR3 in mouse cardiac fibroblasts enhanced activation of p38 and induction of IFN-β and CXCL10 expression. Par1–/– mice also had decreased CXCL10 expression and increased viral levels in the lung after influenza A infection compared with Par1+/+ mice. Our results indicate that the tissue factor/thrombin/PAR-1 pathway enhances IFN-β expression and contributes to the innate immune response during single-stranded RNA viral infection. PMID:23391721

A reassessment of soluble urokinase-type plasminogen activator receptor in glomerular disease

PubMed Central

Spinale, Joann M.; Mariani, Laura H.; Kapoor, Shiv; Zhang, Jidong; Weyant, Robert; Song, Peter X.; Wong, Hetty N.; Troost, Jonathan P.; Gadegbeku, Crystal A.; Gipson, Debbie S.; Kretzler, Matthias; Nihalani, Deepak; Holzman, Lawrence B.

2014-01-01

It has been suggested that soluble urokinase receptor (suPAR) is a causative circulating factor for and a biomarker of focal and segmental glomerulosclerosis (FSGS). Here we undertook validation of these assumptions in both mouse and human models. Injection of recombinant suPAR in wild-type mice did not induce proteinuria within 24 hours. Moreover, a disease phenotype was not seen in an inducible transgenic mouse model that maintained elevated suPAR concentrations for 6 weeks. Plasma and urine suPAR concentrations were evaluated as clinical biomarkers in 241 patients with glomerular disease from the prospective, longitudinal multi-center observational NEPTUNE cohort. The serum suPAR concentration at baseline inversely correlated with estimated glomerular filtration rate (eGFR) and the urine suPAR/creatinine ratio positively correlated with the urine protein/creatinine ratio. After adjusting for eGFR and urine protein, neither the serum nor urine suPAR level was an independent predictor of FSGS histopathology. A multivariable mixed-effects model of longitudinal data evaluated the association between the change in serum suPAR concentration from baseline with eGFR. After adjusting for baseline suPAR concentration, age, gender, proteinuria and time, the change in suPAR from baseline was associated with eGFR, but this association was not different for patients with FSGS as compared to other diagnoses. Thus, these results do not support a pathological role for suPAR in FSGS. PMID:25354239

A reassessment of soluble urokinase-type plasminogen activator receptor in glomerular disease.

PubMed

Spinale, Joann M; Mariani, Laura H; Kapoor, Shiv; Zhang, Jidong; Weyant, Robert; Song, Peter X; Wong, Hetty N; Troost, Jonathan P; Gadegbeku, Crystal A; Gipson, Debbie S; Kretzler, Matthias; Nihalani, Deepak; Holzman, Lawrence B

2015-03-01

It has been suggested that soluble urokinase receptor (suPAR) is a causative circulating factor for and a biomarker of focal and segmental glomerulosclerosis (FSGS). Here we undertook validation of these assumptions in both mouse and human models. Injection of recombinant suPAR in wild-type mice did not induce proteinuria within 24 h. Moreover, a disease phenotype was not seen in an inducible transgenic mouse model that maintained elevated suPAR concentrations for 6 weeks. Plasma and urine suPAR concentrations were evaluated as clinical biomarkers in 241 patients with glomerular disease from the prospective, longitudinal multicenter observational NEPTUNE cohort. The serum suPAR concentration at baseline inversely correlated with estimated glomerular filtration rate (eGFR) and the urine suPAR/creatinine ratio positively correlated with the urine protein/creatinine ratio. After adjusting for eGFR and urine protein, neither the serum nor urine suPAR level was an independent predictor of FSGS histopathology. A multivariable mixed-effects model of longitudinal data evaluated the association between the change in serum suPAR concentration from baseline with eGFR. After adjusting for baseline suPAR concentration, age, gender, proteinuria, and time, the change in suPAR from baseline was associated with eGFR, but this association was not different for patients with FSGS as compared with other diagnoses. Thus these results do not support a pathological role for suPAR in FSGS.

Protease-activated receptor 2 modulates proliferation and invasion of oral squamous cell carcinoma cells.

PubMed

Al-Eryani, Kamal; Cheng, Jun; Abé, Tatsuya; Maruyama, Satoshi; Yamazaki, Manabu; Babkair, Hamzah; Essa, Ahmed; Saku, Takashi

2015-07-01

Based on our previous finding that protease-activated receptor 2 (PAR-2) regulates hemophagocytosis of oral squamous cell carcinoma (SCC) cells, which induces their heme oxygenase 1-dependent keratinization, we have formulated a hypothesis that PAR-2 functions in wider activities of SCC cells. To confirm this hypothesis, we investigated immunohistochemical profiles of PAR-2 in oral SCC tissues and its functional roles in cell proliferation and invasion in SCC cells in culture. The PAR-2 expression modes were determined in 48 surgical tissue specimens of oral SCC. Using oral SCC-derived cell systems, we determined both gene and protein expression levels of PAR-2. SCC cell proliferation and invasive properties were also examined in conditions in which PAR-2 was activated by the synthetic peptide SLIGRL. PAR-2 was immunolocalized in oral SCC and carcinoma in situ cells, especially in those on the periphery of carcinoma cell foci (100% of cases), but not in normal oral epithelia. Its expression at both gene and protein levels was confirmed in 3 oral SCC cell lines including ZK-1. Activation of PAR-2 induced ZK-1 cell proliferation in a dose-dependent manner. PAR-2-activated ZK-1 cells invaded faster than nonactivated ones. The expression of PAR-2 is specific to oral malignancies, and PAR-2 regulates the growth and invasion of oral SCC cells. Copyright © 2015 Elsevier Inc. All rights reserved.

ROPES reveals past land cover and pollen productivity estimates from single pollen records

NASA Astrophysics Data System (ADS)

Theuerkauf, Martin; Couwenberg, John

2018-04-01

Quantitative reconstructions of past vegetation cover commonly require pollen productivity estimates (PPEs). PPEs are calibrated in extensive and rather cumbersome surface-sample studies, and are so far only available for selected regions. Moreover, it may be questioned whether present-day pollen-landcover relationships are valid for palaeo-situations. We here introduce the ROPES approach that simultaneously derives PPEs and mean plant abundances from single pollen records. ROPES requires pollen counts and pollen accumulation rates (PARs, grains cm-2 year-1). Pollen counts are used to reconstruct plant abundances following the REVEALS approach. The principle of ROPES is that changes in plant abundance are linearly represented in observed PAR values. For example, if the PAR of pine doubles, so should the REVEALS reconstructed abundance of pine. Consequently, if a REVEALS reconstruction is ‘correct’ (i.e. ‘correct’ PPEs are used) the ratio ‘PAR over REVEALS’ is constant for each taxon along all samples of a record. With incorrect PPEs, the ratio will instead vary. ROPES starts from random (likely incorrect) PPEs, but then adjusts them using an optimization algorithm with the aim to minimize variation in the ‘PAR over REVEALS’ ratio across the record. ROPES thus simultaneously calculates mean plant abundances and PPEs. We illustrate the approach with test applications on nine synthetic pollen records. The results show that good performance of ROPES requires data sets with high underlying variation, many samples and low noise in the PAR data. ROPES can deliver first landcover reconstructions in regions for which PPEs are not yet available. The PPEs provided by ROPES may then allow for further REVEALS-based reconstructions. Similarly, ROPES can provide insight in pollen productivity during distinct periods of the past such as the Lateglacial. We see a potential to study spatial and temporal variation in pollen productivity for example in relation to site parameters, climate and land use. It may even be possible to detect expansion of non-pollen producing areas in a landscape. Overall, ROPES will help produce more accurate landcover reconstructions and expand reconstructions into new study regions and non-analogue situations of the past. ROPES will be available within the R package DISQOVER.

Persistent kallikrein 5 activation induces atopic dermatitis-like skin architecture independent of PAR2 activity.

PubMed

Zhu, Yanan; Underwood, Joanne; Macmillan, Derek; Shariff, Leila; O'Shaughnessy, Ryan; Harper, John I; Pickard, Chris; Friedmann, Peter S; Healy, Eugene; Di, Wei-Li

2017-11-01

Upregulation of kallikreins (KLKs) including KLK5 has been reported in atopic dermatitis (AD). KLK5 has biological functions that include degrading desmosomal proteins and inducing proinflammatory cytokine secretion through protease-activated receptor 2 (PAR2). However, due to the complex interactions between various cells in AD inflamed skin, it is difficult to dissect the precise and multiple roles of upregulated KLK5 in AD skin. We investigated the effect of upregulated KLK5 on the expression of epidermal-related proteins and cytokines in keratinocytes and on skin architecture. Lesional and nonlesional AD skin biopsies were collected for analysis of morphology and protein expression. The relationship between KLK5 and barrier-related molecules was investigated using an ex vivo dermatitis skin model with transient KLK5 expression and a cell model with persistent KLK5 expression. The influence of upregulated KLK5 on epidermal morphology was investigated using an in vivo skin graft model. Upregulation of KLK5 and abnormal expression of desmoglein 1 (DSG1) and filaggrin, but not PAR2 were identified in AD skin. PAR2 was increased in response to transient upregulation of KLK5, whereas persistently upregulated KLK5 did not show this effect. Persistently upregulated KLK5 degraded DSG1 and stimulated secretion of IL-8, IL-10, and thymic stromal lymphopoietin independent of PAR2 activity. With control of higher KLK5 activity by the inhibitor sunflower trypsin inhibitor G, restoration of DSG1 expression and a reduction in AD-related cytokine IL-8, thymic stromal lymphopoietin, and IL-10 secretion were observed. Furthermore, persistently elevated KLK5 could induce AD-like skin architecture in an in vivo skin graft model. Persistently upregulated KLK5 resulted in AD-like skin architecture and secretion of AD-related cytokines from keratinocytes in a PAR2 independent manner. Inhibition of KLK5-mediated effects may offer potential as a therapeutic approach in AD. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

ParFit: A Python-Based Object-Oriented Program for Fitting Molecular Mechanics Parameters to ab Initio Data.

PubMed

Zahariev, Federico; De Silva, Nuwan; Gordon, Mark S; Windus, Theresa L; Dick-Perez, Marilu

2017-03-27

A newly created object-oriented program for automating the process of fitting molecular-mechanics parameters to ab initio data, termed ParFit, is presented. ParFit uses a hybrid of deterministic and stochastic genetic algorithms. ParFit can simultaneously handle several molecular-mechanics parameters in multiple molecules and can also apply symmetric and antisymmetric constraints on the optimized parameters. The simultaneous handling of several molecules enhances the transferability of the fitted parameters. ParFit is written in Python, uses a rich set of standard and nonstandard Python libraries, and can be run in parallel on multicore computer systems. As an example, a series of phosphine oxides, important for metal extraction chemistry, are parametrized using ParFit. ParFit is in an open source program available for free on GitHub ( https://github.com/fzahari/ParFit ).

The role of protease-activated receptor-2 on pulmonary neutrophils in the innate immune response to cockroach allergen

PubMed Central

2012-01-01

Background Serine proteases in German cockroach (GC) have been shown to mediate allergic airway inflammation through the activation of protease activated receptor (PAR)-2. Neutrophils play an important role in regulating the innate immune response, and are recruited into the airways following GC frass exposure. As such, we investigated the role of PAR-2 in airway neutrophil recruitment, activation and cytokine production following allergen exposure. Methods Wild type and PAR-2-deficient mice were administered a single intratracheal instillation of PBS or GC frass and neutrophil recruitment, expression of PAR-2, CD80, CD86, and MHC class II were assessed by flow cytometry and levels of tumor necrosis factor (TNF)α was assessed by ELISA. Uptake of AlexaFluor 405-labeled GC frass by neutrophils was performed by flow cytometry. Results Neutrophil recruitment in the lung and airways following GC frass exposure was significantly decreased in PAR-2-deficient mice compared to wild type mice. GC frass exposure increased the level of PAR-2 on pulmonary neutrophils and increased numbers of PAR-2-positive neutrophils were found in the lungs; however PAR-2 did not play a role in meditating allergen uptake. Comparing wild type and PAR-2-deficient mice, we found that a single exposure to GC frass increased levels of CD80 and CD86 on pulmonary neutrophils, an effect which was independent of PAR-2 expression. Neutrophils isolated from the whole lungs of naïve PAR-2-deficient mice treated ex vivo with GC frass produced significantly less TNFα than in similarly treated wild type neutrophils. Lastly, neutrophils were isolated from the bronchoalveolar lavage fluid of wild type and PAR-2-deficient mice following a single intratracheal exposure to GC frass. Airway neutrophils from PAR-2-deficient mice released substantially decreased levels of TNFα, suggesting a role for PAR-2 in neutrophil-derived cytokine production. Conclusions Together these data suggest PAR-2 expression can be upregulated on lung neutrophils following allergen exposure and the consequence is altered release of TNFα which could drive the early innate immune response. PMID:22954301

Increased mast cell expression of PAR-2 in skin inflammatory diseases and release of IL-8 upon PAR-2 activation.

PubMed

Carvalho, Ricardo Filipe da Silva; Nilsson, Gunnar; Harvima, Ilkka Tapani

2010-02-01

Mast cells are increasingly present in the lesional skin of chronic skin inflammatory diseases including psoriasis and basal cell carcinoma (BCC). It has previously been shown that proteinase-activated receptor (PAR)-2 is expressed by mast cells, and tryptase is a potent activator of this receptor. In this study, skin biopsies from both healthy-looking and lesional skin of patients with psoriasis and superficial spreading BCC were collected and the expression of PAR-2 immunoreactivity in tryptase-positive mast cells was analysed. PAR-2 expression was confirmed in vitro in different mast cell populations. Cord-blood derived mast cells (CBMC) were stimulated with a PAR-2 activating peptide, 2-furoyl-LIGRLO-NH(2). Consequently, IL-8 and histamine production was analysed in the supernatants. We observed a significant increase in the percentage of mast cells expressing PAR-2 in the lesional skin of psoriasis and BCC patients compared with the healthy-looking skin. HMC-1.2, LAD-2 and CBMC mast cells all expressed PAR-2 both intracellularly and on the cell surface. CBMC activation with the PAR-2 activating peptide resulted in an increased secretion of IL-8, but no histamine release was observed. Furthermore, both PAR-2 and IL-8 were co-localized to the same tryptase-positive mast cells in the lesional BCC skin. These results show that mast cells express increased levels of PAR-2 in chronic skin inflammation. Also, mast cells can be activated by a PAR-2 agonist to secrete IL-8, a chemokine which can contribute to the progress of inflammation.

Adaptor Protein Complex-2 (AP-2) and Epsin-1 Mediate Protease-activated Receptor-1 Internalization via Phosphorylation- and Ubiquitination-dependent Sorting Signals*

PubMed Central

Chen, Buxin; Dores, Michael R.; Grimsey, Neil; Canto, Isabel; Barker, Breann L.; Trejo, JoAnn

2011-01-01

Signaling by protease-activated receptor-1 (PAR1), a G protein-coupled receptor (GPCR) for thrombin, is regulated by desensitization and internalization. PAR1 desensitization is mediated by β-arrestins, like most classic GPCRs. In contrast, internalization of PAR1 occurs through a clathrin- and dynamin-dependent pathway independent of β-arrestins. PAR1 displays two modes of internalization. Constitutive internalization of unactivated PAR1 is mediated by the clathrin adaptor protein complex-2 (AP-2), where the μ2-adaptin subunit binds directly to a tyrosine-based motif localized within the receptor C-tail domain. However, AP-2 depletion only partially inhibits agonist-induced internalization of PAR1, suggesting a function for other clathrin adaptors in this process. Here, we now report that AP-2 and epsin-1 are both critical mediators of agonist-stimulated PAR1 internalization. We show that ubiquitination of PAR1 and the ubiquitin-interacting motifs of epsin-1 are required for epsin-1-dependent internalization of activated PAR1. In addition, activation of PAR1 promotes epsin-1 de-ubiquitination, which may increase its endocytic adaptor activity to facilitate receptor internalization. AP-2 also regulates activated PAR1 internalization via recognition of distal C-tail phosphorylation sites rather than the canonical tyrosine-based motif. Thus, AP-2 and epsin-1 are both required to promote efficient internalization of activated PAR1 and recognize discrete receptor sorting signals. This study defines a new pathway for internalization of mammalian GPCRs. PMID:21965661

Planar Cell Polarity Breaks the Symmetry of PAR Protein Distribution prior to Mitosis in Drosophila Sensory Organ Precursor Cells.

PubMed

Besson, Charlotte; Bernard, Fred; Corson, Francis; Rouault, Hervé; Reynaud, Elodie; Keder, Alyona; Mazouni, Khalil; Schweisguth, François

2015-04-20

During development, cell-fate diversity can result from the unequal segregation of fate determinants at mitosis. Polarization of the mother cell is essential for asymmetric cell division (ACD). It often involves the formation of a cortical domain containing the PAR complex proteins Par3, Par6, and atypical protein kinase C (aPKC). In the fly notum, sensory organ precursor cells (SOPs) divide asymmetrically within the plane of the epithelium and along the body axis to generate two distinct cells. Fate asymmetry depends on the asymmetric localization of the PAR complex. In the absence of planar cell polarity (PCP), SOPs divide with a random planar orientation but still asymmetrically, showing that PCP is dispensable for PAR asymmetry at mitosis. To study when and how the PAR complex localizes asymmetrically, we have used a quantitative imaging approach to measure the planar polarization of the proteins Bazooka (Baz, fly Par3), Par6, and aPKC in living pupae. By using imaging of functional GFP-tagged proteins with image processing and computational modeling, we find that Baz, Par6, and aPKC become planar polarized prior to mitosis in a manner independent of the AuroraA kinase and that PCP is required for the planar polarization of Baz, Par6, and aPKC during interphase. This indicates that a "mitosis rescue" mechanism establishes asymmetry at mitosis in PCP mutants. This study therefore identifies PCP as the initial symmetry-breaking signal for the planar polarization of PAR proteins in asymmetrically dividing SOPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prognosis in adenocarcinomas of lower oesophagus, gastro-oesophageal junction and cardia evaluated by uPAR-immunohistochemistry.

PubMed

Laerum, Ole Didrik; Ovrebo, Kjell; Skarstein, Arne; Christensen, Ib Jarle; Alpízar-Alpízar, Warner; Helgeland, Lars; Danø, Keld; Nielsen, Boye Schnack; Illemann, Martin

2012-08-01

Adenocarcinomas of lower oesophagus, gastro-oesophageal junction and cardia in humans are highly invasive tumours with poor prognosis. The localisation of urokinase-type plasminogen activator receptor (uPAR) was determined in 66 patients; 60 with adenocarcinomas and six cases with Barrett's oesophagus. uPAR was expressed in nearly all cases of invasive adenocarcinomas by populations of cancer cells, macrophages and myofibroblasts at both the invasion front and the tumour core. In areas with high-grade dysplasia or with Barrett's metaplasia adjacent to the tumour tissue, no uPAR-immunoreactivity was found. High local expression of uPAR, therefore, appears to be a characteristic marker for invasive behaviour in this tumour, suggesting that uPAR's contribution to matrix degradation during invasive growth is a late event in carcinogenesis. Using a scoring system for semiquantitative estimation of uPAR-positivity on immmunohistochemically stained specimens, a significant association was found between poor overall survival and high uPAR-score for cancer cells in the tumour core and for macrophages peripherally at the tumour invasion zone. In multivariate analysis, these two uPAR-scores were confirmed as highly significant prognostic parameters independent of Tumour, Node, Metastasis (TNM)-stage and World Health Organization (WHO) classification. The proteolytic action of these malignant and nonmalignant accessory cells thus seemed to follow two main patterns: one dominated by uPAR positive cancer cells and one by uPAR-positive macrophages. Scoring of uPAR-positivity might be a useful parameter for onset of invasion and prognosis in these adenocarcinomas. Copyright © 2011 UICC.

Centromere Binding and Evolution of Chromosomal Partition Systems in the Burkholderiales

PubMed Central

Passot, Fanny M.; Calderon, Virginie; Fichant, Gwennaele; Lane, David

2012-01-01

How split genomes arise and evolve in bacteria is poorly understood. Since each replicon of such genomes encodes a specific partition (Par) system, the evolution of Par systems could shed light on their evolution. The cystic fibrosis pathogen Burkholderia cenocepacia has three chromosomes (c1, c2, and c3) and one plasmid (pBC), whose compatibility depends on strictly specific interactions of the centromere sequences (parS) with their cognate binding proteins (ParB). However, the Par systems of B. cenocepacia c2, c3, and pBC share many features, suggesting that they arose within an extended family. Database searching revealed seven subfamilies of Par systems like those of B. cenocepacia. All are from plasmids and secondary chromosomes of the Burkholderiales, which reinforces the proposal of an extended family. The subfamily of the Par system of B. cenocepacia c3 includes plasmid variants with parS sequences divergent from that of c3. Using electrophoretic mobility shift assay (EMSA), we found that ParB-c3 binds specifically to centromeres of these variants, despite high DNA sequence divergence. We suggest that the Par system of B. cenocepacia c3 has preserved the features of an ancestral system. In contrast, these features have diverged variably in the plasmid descendants. One such descendant is found both in Ralstonia pickettii 12D, on a free plasmid, and in Ralstonia pickettii 12J, on a plasmid integrated into the main chromosome. These observations suggest that we are witnessing a plasmid-chromosome interaction from which a third chromosome will emerge in a two-chromosome species. PMID:22522899

Centromere binding and evolution of chromosomal partition systems in the Burkholderiales.

PubMed

Passot, Fanny M; Calderon, Virginie; Fichant, Gwennaele; Lane, David; Pasta, Franck

2012-07-01

How split genomes arise and evolve in bacteria is poorly understood. Since each replicon of such genomes encodes a specific partition (Par) system, the evolution of Par systems could shed light on their evolution. The cystic fibrosis pathogen Burkholderia cenocepacia has three chromosomes (c1, c2, and c3) and one plasmid (pBC), whose compatibility depends on strictly specific interactions of the centromere sequences (parS) with their cognate binding proteins (ParB). However, the Par systems of B. cenocepacia c2, c3, and pBC share many features, suggesting that they arose within an extended family. Database searching revealed seven subfamilies of Par systems like those of B. cenocepacia. All are from plasmids and secondary chromosomes of the Burkholderiales, which reinforces the proposal of an extended family. The subfamily of the Par system of B. cenocepacia c3 includes plasmid variants with parS sequences divergent from that of c3. Using electrophoretic mobility shift assay (EMSA), we found that ParB-c3 binds specifically to centromeres of these variants, despite high DNA sequence divergence. We suggest that the Par system of B. cenocepacia c3 has preserved the features of an ancestral system. In contrast, these features have diverged variably in the plasmid descendants. One such descendant is found both in Ralstonia pickettii 12D, on a free plasmid, and in Ralstonia pickettii 12J, on a plasmid integrated into the main chromosome. These observations suggest that we are witnessing a plasmid-chromosome interaction from which a third chromosome will emerge in a two-chromosome species.

Mesure du coewicient d'absorption optique dans le silicium multicristallin de type P pour photopiles solaires

NASA Astrophysics Data System (ADS)

Gervais, J.

1993-07-01

The minority carrier diffusion length L characterizes the electrical quality of multicrystalline silicon wafers used for photovoltaics. Its determination before and after different treatments (impurity diffusion, passivation, metallisation) is needfull and requires the accurate knowledge of the optical absorption coefficient α in the near infrared. We have determinated the spectral variation of α in the range between 0.86 and 1.06 μm and we propose an analytic expression which is very close to those proposed for solar grade single crystals. In addition we have verified that the values of α are not affected by long phosphorus diffusion needed to getter metallic impurities. La longueur de diffusion des porteurs minoritaires L caractérise la qualité du silicium multicristallin utilisé pour la conversion photovoltaïque. Sa détermination avant et après les divers traitements (diffusion d'impuretés, passivation des défauts, métallisation) est indispensable et nécessite la connaissance précise du coefficient d'absorption optique α dans le proche infrarouge. Nous avons déterminé expérimentalement la variation spectrale de α entre 0,86 et 1,06 μm et nous proposons un développement qui est très proche de ceux trouvés dans des monocristaux de silicium de qualité solaire. La variation de α n'est pas influencée par des diffusions de phosphore prolongées nécessaires à l'extraction et au piégeage d'impuretés métalliques.

Doxycycline directly targets PAR1 to suppress tumor progression

PubMed Central

Qin, Yuan; Gu, Ju; Sun, Bo; Liu, Yanrong; Jing, Xiangyan; Hu, Xuejiao; Zhang, Peng; Zhou, Honggang; Sun, Tao; Yang, Cheng

2017-01-01

Doxycycline have been reported to exert anti-cancer activity and have been assessed as anti-cancer agents in clinical trials. However, the direct targets of doxycycline in cancer cells remain unclear. In this study, we used a chemical proteomics approach to identify the Protease-activated receptor 1 (PAR1) as a specific target of inhibition of doxycycline. Binding assays and single-molecule imaging assays were performed to confirm the inhibition of doxycycline to PAR1. The effect of doxycycline on multi-omics and cell functions were assessed based on a PAR1/thrombin model. Molecular docking and molecular dynamic simulations revealed that doxycycline interacts with key amino acids in PAR1. Mutation of PAR1 further confirmed the computation-based results. Moreover, doxycycline provides highly selective inhibition of PAR1 signaling in tumors in vitro and in vivo. Using pathological clinical samples co-stained for doxycycline and PAR1, it was found that doxycycline fluorescence intensity and PAR1 expression shown a clear positive correlation. Thus, doxycycline may be a useful targeted anti-cancer drug that should be further investigated in clinical trials. PMID:28187433

Doxycycline directly targets PAR1 to suppress tumor progression.

PubMed

Zhong, Weilong; Chen, Shuang; Zhang, Qiang; Xiao, Ting; Qin, Yuan; Gu, Ju; Sun, Bo; Liu, Yanrong; Jing, Xiangyan; Hu, Xuejiao; Zhang, Peng; Zhou, Honggang; Sun, Tao; Yang, Cheng

2017-03-07

Doxycycline have been reported to exert anti-cancer activity and have been assessed as anti-cancer agents in clinical trials. However, the direct targets of doxycycline in cancer cells remain unclear. In this study, we used a chemical proteomics approach to identify the Protease-activated receptor 1 (PAR1) as a specific target of inhibition of doxycycline. Binding assays and single-molecule imaging assays were performed to confirm the inhibition of doxycycline to PAR1. The effect of doxycycline on multi-omics and cell functions were assessed based on a PAR1/thrombin model. Molecular docking and molecular dynamic simulations revealed that doxycycline interacts with key amino acids in PAR1. Mutation of PAR1 further confirmed the computation-based results. Moreover, doxycycline provides highly selective inhibition of PAR1 signaling in tumors in vitro and in vivo. Using pathological clinical samples co-stained for doxycycline and PAR1, it was found that doxycycline fluorescence intensity and PAR1 expression shown a clear positive correlation. Thus, doxycycline may be a useful targeted anti-cancer drug that should be further investigated in clinical trials.

Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.

PubMed

Facciuto, Florencia; Bugnon Valdano, Marina; Marziali, Federico; Massimi, Paola; Banks, Lawrence; Cavatorta, Ana Laura; Gardiol, Daniela

2014-05-01

High-risk human papillomavirus (HPV) infection is the principal risk factor for the development of cervical cancer. The HPV E6 oncoprotein has the ability to target and interfere with several PSD-95/DLG/ZO-1 (PDZ) domain-containing proteins that are involved in the control of cell polarity. This function can be significant for E6 oncogenic activity because a deficiency in cell polarisation is a marker of tumour progression. The establishment and control of polarity in epithelial cells depend on the correct asymmetrical distribution of proteins and lipids at the cell borders and on specialised cell junctions. In this report, we have investigated the effects of HPV E6 protein on the polarity machinery, with a focus on the PDZ partitioning defective 3 (Par3) protein, which is a key component of tight junctions (TJ) and the polarity network. We demonstrate that E6 is able to bind and induce the mislocalisation of Par3 protein in a PDZ-dependent manner without significant reduction in Par3 protein levels. In addition, the high-risk HPV-18 E6 protein promotes a delay in TJ formation when analysed by calcium switch assays. Taken together, the data presented in this study contribute to our understanding of the molecular mechanism by which HPVs induce the loss of cell polarity, with potential implications for the development and progression of HPV-associated tumours. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Enhanced scratching evoked by PAR-2 agonist and 5-HT but not histamine in a mouse model of chronic dry skin itch.

PubMed

Akiyama, T; Carstens, M Iodi; Carstens, E

2010-11-01

Chronic itch is a symptom of many skin conditions and systemic disease, and it has been hypothesized that the chronic itch may result from sensitization of itch-signaling pathways. We induced experimental chronic dry skin on the rostral back of mice, and observed a significant increase in spontaneous hindlimb scratches directed to the dry skin. Spontaneous scratching was significantly attenuated by a PAR-2 antibody and 5-HT2A receptor antagonist, indicating activation of these receptors by endogenous mediators released under dry skin conditions. We also observed a significant increase in the number of scratch bouts evoked by acute intradermal injections of a protease-activated receptor (PAR)-2 agonist and serotonin (5-HT), but not histamine. We additionally investigated if pruritogen-evoked activity of dorsal root ganglion (DRG) neurons is enhanced in this model. DRG cells from dry skin mice exhibited significantly larger responses to the PAR-2 agonist and 5-HT, but not histamine. Spontaneous scratching may reflect ongoing itch, and enhanced pruritogen-evoked scratching may represent hyperknesis (enhanced itch), both potentially due to sensitization of itch-signaling neurons. The correspondence between enhanced behavioral scratching and DRG cell responses suggest that peripheral pruriceptors that respond to proteases and 5-HT, but not histamine, may be sensitized in dry skin itch. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Ultra-thin enhanced-absorption long-wave infrared detectors

NASA Astrophysics Data System (ADS)

Wang, Shaohua; Yoon, Narae; Kamboj, Abhilasha; Petluru, Priyanka; Zheng, Wanhua; Wasserman, Daniel

2018-02-01

We propose an architecture for enhanced absorption in ultra-thin strained layer superlattice detectors utilizing a hybrid optical cavity design. Our detector architecture utilizes a designer-metal doped semiconductor ground plane beneath the ultra-subwavelength thickness long-wavelength infrared absorber material, upon which we pattern metallic antenna structures. We demonstrate the potential for near 50% detector absorption in absorber layers with thicknesses of approximately λ0/50, using realistic material parameters. We investigate detector absorption as a function of wavelength and incidence angle, as well as detector geometry. The proposed device architecture offers the potential for high efficiency detectors with minimal growth costs and relaxed design parameters.

Sorbitol increases muscle glucose uptake ex vivo and inhibits intestinal glucose absorption ex vivo and in normal and type 2 diabetic rats.

PubMed

Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

2017-04-01

Previous studies have suggested that sorbitol, a known polyol sweetener, possesses glycemic control potentials. However, the effect of sorbitol on intestinal glucose absorption and muscle glucose uptake still remains elusive. The present study investigated the effects of sorbitol on intestinal glucose absorption and muscle glucose uptake as possible anti-hyperglycemic or glycemic control potentials using ex vivo and in vivo experimental models. Sorbitol (2.5% to 20%) inhibited glucose absorption in isolated rat jejuna (IC 50 = 14.6% ± 4.6%) and increased glucose uptake in isolated rat psoas muscle with (GU 50 = 3.5% ± 1.6%) or without insulin (GU 50 = 7.0% ± 0.5%) in a concentration-dependent manner. Furthermore, sorbitol significantly delayed gastric emptying, accelerated digesta transit, inhibited intestinal glucose absorption, and reduced blood glucose increase in both normoglycemic and type 2 diabetic rats after 1 h of coingestion with glucose. Data of this study suggest that sorbitol exhibited anti-hyperglycemic potentials, possibly via increasing muscle glucose uptake ex vivo and reducing intestinal glucose absorption in normal and type 2 diabetic rats. Hence, sorbitol may be further investigated as a possible anti-hyperglycemic sweetener.

Dishevelled-induced phosphorylation regulates membrane localization of Par1b

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

Terabayashi, Takeshi; Funato, Yosuke; Miki, Hiroaki, E-mail: hmiki@protein.osaka-u.ac.jp

2008-10-31

Par1b is an evolutionarily conserved kinase that plays crucial roles in cell polarity. Controlling intracellular localization of Par1b is important for its biological activity. We previously reported that Wnt stimulation or expression of Dvl promotes accumulation of Par1b in the membrane (T. Terabayashi, T.J. Itoh, H. Yamaguchi, Y. Yoshimura, Y. Funato, S. Ohno, H. Miki, Polarity-Regulating Kinase Partitioning-Defective 1/Microtubule Affinity-Regulating Kinase 2 Negatively Regulates Development of Dendrites on Hippocampal Neurons, J. Neurosci. 27 (2007) 13098-13107). However, its molecular mechanism remains unclear. Here we show the importance of Par1b phosphorylation in the regulation of membrane localization. We find that Thr-324 ismore » phosphorylated in a Dvl-dependent manner. Interestingly, the conversion of Thr-324 to Glu results in a significant accumulation of Par1b in the membrane, without any effects on the kinase activity. Moreover, the phospho-mimicking Par1b mutant does not antagonistically function against Dvl in microtubule stabilization and neurite extension, although wildtype Par1b does. These results suggest that membrane accumulation of Par1b induced by Dvl is regulated by its phosphorylation status, which is important for Par1b to regulate the microtubule dynamics.« less

Expression of protease-activated-receptor 2 (PAR-2) in human esophageal mucosa.

PubMed

Inci, Kamuran; Edebo, Anders; Olbe, Lars; Casselbrant, Anna

2009-01-01

The role of duodenal reflux in gastroesophageal reflux disease (GERD) containing bile salts and pancreatic enzymes (with special attention to trypsin) is still under discussion. Proteinase-activated receptors (PARs) are a novel family and PAR-2 is a unique member of this family because it is activated by trypsin. The aim of the present study was to examine the presence and the position of the PAR-2 receptor in human esophageal mucosa in different subgroups of GERD. Distal biopsies taken from healthy controls, patients with erosive reflux disease (ERD), patients with specialized intestinal metaplasia (SIM) and adenocarcinoma were analyzed for the PAR-2 receptor with reverse-transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry. Gene transcripts for the PAR-2 receptor were found in all groups, with increased levels in SIM patients compared to controls. However, this visual pattern was not seen for the protein expression of the PAR-2 receptor showing no apparent quantitative differences between the groups. Immunohistochemistry revealed distinct staining for the PAR-2 receptor in the luminal part of the esophageal epithelium. The localization of the PAR-2 receptor indicates that the receptor can be cleaved and activated by trypsin in duodenogastric esophageal refluxate. The data thus suggest that the trypsin-PAR-2 pathway may be involved in the pathogenesis of GERD.

Transient early neurotrophin release and delayed inflammatory cytokine release by microglia in response to PAR-2 stimulation.

PubMed

Chen, Chen-Wen; Chen, Qian-Bo; Ouyang, Qing; Sun, Ji-Hu; Liu, Fang-Ting; Song, Dian-Wen; Yuan, Hong-Bin

2012-06-25

Activated microglia exerts both beneficial and deleterious effects on neurons, but the signaling mechanism controlling these distinct responses remain unclear. We demonstrated that treatment of microglial cultures with the PAR-2 agonist, 2-Furoyl-LIGRLO-NH2, evoked early transient release of BDNF, while sustained PAR-2 stimulation evoked the delayed release of inflammatory cytokines (IL-1 β and TNF-α) and nitric oxide. Culture medium harvested during the early phase (at 1 h) of microglial activation induced by 2-Furoyl-LIGRLO-NH2 (microglial conditioned medium, MCM) had no deleterious effects on cultured neurons, while MCM harvested during the late phase (at 72 h) promoted DNA fragmentation and apoptosis as indicated by TUNEL and annexin/PI staining. Blockade of PAR-1 during the early phase of PAR-2 stimulation enhanced BDNF release (by 11%, small but significant) while a PAR-1 agonist added during the late phase (24 h after 2-Furoyl-LIGRLO-NH2 addition) suppressed the release of cytokines and NO. The neuroprotective and neurotoxic effects of activated microglial exhibit distinct temporal profiles that are regulated by PAR-1 and PAR-2 stimulation. It may be possible to facilitate neuronal recovery and repair by appropriately timed stimulation and inhibition of microglial PAR-1 and PAR-2 receptors.

Mitogenic signaling of urokinase receptor-deficient kidney fibroblasts: actions of an alternative urokinase receptor and LDL receptor-related protein.

PubMed

Zhang, Guoqiang; Cai, Xiaohe; López-Guisa, Jesús M; Collins, Sarah J; Eddy, Allison A

2004-08-01

The urokinase receptor (uPAR) attenuates myofibroblast recruitment and fibrosis in the kidney. This study examined the role of uPAR and its co-receptor LDL receptor-related protein (LRP) in the regulation of kidney fibroblast proliferation and extracellular signal-regulated kinase (ERK) signaling. Compared with uPAR+/+ cells, uPAR-/- kidney fibroblasts were hyperproliferative. UPAR-/- fibroblast proliferation was 60% inhibited by an ERK kinase inhibitor. LRP protein was reduced and extracellular accumulation of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) proteins were greater in uPAR-/- cultures. Addition of functional uPA protein or LRP antisense RNA significantly increased ERK signaling and cell mitosis in both genotypes. Enhanced uPAR-/- fibroblast proliferation was reversed by a recombinant nonfunctional uPA peptide. The density of cell-bound fluor-uPA was similar between uPAR-/- and uPAR+/+ fibroblasts (78 +/- 6 versus 92 +/- 16 units). These data suggest that uPAR-deficient kidney fibroblasts express lower levels of its scavenger co-receptor LRP, resulting in greater extracellular accumulation of uPA and PAI-1. Enhanced proliferation of uPAR-/- fibroblasts seems to be mediated by uPA-dependent ERK signaling via an alternative urokinase receptor.

An enzyme-linked immunosorbent assay-based system for determining the physiological level of poly(ADP-ribose) in cultured cells.

PubMed

Ida, Chieri; Yamashita, Sachiko; Tsukada, Masaki; Sato, Teruaki; Eguchi, Takayuki; Tanaka, Masakazu; Ogata, Shin; Fujii, Takahiro; Nishi, Yoshisuke; Ikegami, Susumu; Moss, Joel; Miwa, Masanao

2016-02-01

PolyADP-ribosylation is mediated by poly(ADP-ribose) (PAR) polymerases (PARPs) and may be involved in various cellular events, including chromosomal stability, DNA repair, transcription, cell death, and differentiation. The physiological level of PAR is difficult to determine in intact cells because of the rapid synthesis of PAR by PARPs and the breakdown of PAR by PAR-degrading enzymes, including poly(ADP-ribose) glycohydrolase (PARG) and ADP-ribosylhydrolase 3. Artifactual synthesis and/or degradation of PAR likely occurs during lysis of cells in culture. We developed a sensitive enzyme-linked immunosorbent assay (ELISA) to measure the physiological levels of PAR in cultured cells. We immediately inactivated enzymes that catalyze the synthesis and degradation of PAR. We validated that trichloroacetic acid is suitable for inactivating PARPs, PARG, and other enzymes involved in metabolizing PAR in cultured cells during cell lysis. The PAR level in cells harvested with the standard radioimmunoprecipitation assay buffer was increased by 450-fold compared with trichloroacetic acid for lysis, presumably because of activation of PARPs by DNA damage that occurred during cell lysis. This ELISA can be used to analyze the biological functions of polyADP-ribosylation under various physiological conditions in cultured cells. Copyright © 2015 Elsevier Inc. All rights reserved.

The intracellular carboxyl tail of the PAR-2 receptor controls intracellular signaling and cell death.

PubMed

Zhu, Zhihui; Stricker, Rolf; Li, Rong yu; Zündorf, Gregor; Reiser, Georg

2015-03-01

The protease-activated receptors are a group of unique G protein-coupled receptors, including PAR-1, PAR-2, PAR-3 and PAR-4. PAR-2 is activated by multiple trypsin-like serine proteases, including trypsin, tryptase and coagulation proteases. The clusters of phosphorylation sites in the PAR-2 carboxyl tail are suggested to be important for the binding of adaptor proteins to initiate intracellular signaling to Ca(2+) and mitogen-activated protein kinases. To explore the functional role of PAR-2 carboxyl tail in controlling intracellular Ca(2+), ERK and AKT signaling, a series of truncated mutants containing different clusters of serines/threonines were generated and expressed in HEK293 cells. Firstly, we observed that lack of the complete C-terminus of PAR-2 in a mutated receptor gave a relatively low level of localization on the cell plasma membrane. Secondly, the shortened carboxyl tail containing 13 amino acids was sufficient for receptor internalization. Thirdly, the cells expressing truncation mutants showed deficits in their capacity to couple to intracellular Ca(2+) and ERK and AKT signaling upon trypsin challenge. In addition, HEK293 cells carrying different PAR-2 truncation mutants displayed decreased levels of cell survival after long-lasting trypsin stimulation. In summary, the PAR-2 carboxyl tail was found to control the receptor localization, internalization, intracellular Ca(2+) responses and signaling to ERK and AKT. The latter can be considered to be important for cell death control.

PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity.

PubMed

Fukushima, Henrique; Alves, Vanessa Tubero Euzebio; Carvalho, Verônica Franco de; Ambrósio, Lucas Macedo Batitucci; Eichler, Rosangela Aparecida Dos Santos; Carvalho, Maria Helena Catelli de; Saraiva, Luciana; Holzhausen, Marinella

2017-01-26

Recent studies investigating protease-activated receptor type 2 (PAR-2) suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF) of patients with moderate chronic periodontitis (MP). The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19) at baseline, and from MP patients (n = 19) and severe chronic periodontitis (SP) (n = 19) patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA) in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR). PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p <0.05) PAR-2 expression in patients with periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

Effect of Par Frying on Composition and Texture of Breaded and Battered Catfish

PubMed Central

Woods, Kristin; Lea, Jeanne M.; Brashear, Suzanne S.; Boue, Stephen M.; Daigle, Kim W.; Bett-Garber, Karen L.

2018-01-01

Catfish is often consumed as a breaded and battered fried product; however, there is increasing interest in breaded and battered baked products as a healthier alternative. Par frying can improve the texture properties of breaded and battered baked products, but there are concerns about the increase in lipid uptake from par frying. The objective of this study was to examine the effect of different batters (rice, corn, and wheat) and the effect of par frying on the composition and texture properties of baked catfish. Catfish fillets were cut strips and then coated with batters, which had similar viscosities. Half of the strips were par fried in 177 °C vegetable oil for 1 min and the other half were not par fried. Samples were baked at 177 °C for 25 min. Analysis included % batter adhesion, cooking loss, protein, lipid, ash, and moisture, plus hardness and fracture quality measured using a texture analyzer. A trained sensory panel evaluated both breading and flesh texture attributes. Results found the lipid content of par fried treatments were significantly higher for both corn and wheat batters than for non-par fried treatments. Sensory analysis indicated that the texture of the coatings in the par fried treatments were significantly greater for hardness attributes. Fillet flakiness was significantly greater in the par fried treatments and corn-based batters had moister fillet strips compared to the wheat flour batters. Texture analyzer hardness values were higher for the par fried treatments. PMID:29570660

Combination with CK19 Might Increase the Prognostic Power of Hep Par 1 in Hepatocellular Carcinoma after Curative Resection.

PubMed

Jin, Ye; Liang, Zhi-Yong; Zhou, Wei-Xun; Zhou, Li

2017-07-31

Hepatocyte Paraffin 1 (Hep Par 1) and cytokeratin 19 (CK19) were shown to be associated with post-surgical prognosis of hepatocellular carcinoma (HCC). However, further validation might be needed. Besides, their combined evaluation has not been reported. The present study was designed to address the issues. Expressions of Hep Par 1 and CK19 were detected using tissue microarray-based immunohistochemical staining in 79 patients with HCC underwent curative hepatectomy. Their associations with cliniopathologic variables, overall and recurrence-free survival were analyzed. Hep Par 1 was highly expressed in 61 patients (77.2%), whereas CK19 was positive in 8 patients (10.1%). Moreover, expressions of these two proteins were all associated with tumor-node-metastasis (TNM) stage and vascular invasion. It was found that high Hep Par 1 expression was univariately associated with good overall and recurrence-free survival, while CK19 was marginally prognostic. Also in univariate analyses, combination of the two markers more effectively predicted for long-term prognosis in HCC than Hep Par 1 did. However, neither Hep Par 1 nor Hep Par 1/CK19 was multivariately significant. Finally, Hep Par 1/CK19 combined with TNM stage might obtain more satisfactory outcome prediction, especially for overall survival. Combination of CK19 with Hep Par 1 might have higher prognostic power, which might be further improved by adding TNM stage, than Hep Par 1 alone, in resected HCC. Of course, subsequent confirmation is necessary.

Par-4, a Gene Required for Cytoplasmic Localization and Determination of Specific Cell Types in Caenorhabditis Elegans Embryogenesis

PubMed Central

Morton, D. G.; Roos, J. M.; Kemphues, K. J.

1992-01-01

Specification of some cell fates in the early Caenorhabditis elegans embryo is mediated by cytoplasmic localization under control of the maternal genome. Using nine newly isolated mutations, and two existing mutations, we have analyzed the role of the maternally expressed gene par-4 in cytoplasmic localization. We recovered seven new par-4 alleles in screens for maternal effect lethal mutations that result in failure to differentiate intestinal cells. Two additional par-4 mutations were identified in noncomplementation screens using strains with a high frequency of transposon mobility. All 11 mutations cause defects early in development of embryos produced by homozygous mutant mothers. Analysis with a deficiency in the region indicates that it33 is a strong loss-of-function mutation. par-4(it33) terminal stage embryos contain many cells, but show no morphogenesis, and are lacking intestinal cells. Temperature shifts with the it57ts allele suggest that the critical period for both intestinal differentiation and embryo viability begins during oogenesis, about 1.5 hr before fertilization, and ends before the four-cell stage. We propose that the primary function of the par-4 gene is to act as part of a maternally encoded system for cytoplasmic localization in the first cell cycle, with par-4 playing a particularly important role in the determination of intestine. Analysis of a par-4;par-2 double mutant suggests that par-4 and par-2 gene products interact in this system. PMID:1582558

Lack of concordance in microarray gene expression responses to Phenobarbital in companion aged FFPE and Frozen liver samples

EPA Science Inventory

Despite the immense potential value of public and private biorepositories, direct utilization of archival tissues for molecular profiling has been limited. A major reason for this limited use is the difficulty in obtaining reliable transcriptomic profiles from formalin-fixed par...

75 FR 56919 - Port Access Route Study: The Approaches to San Francisco

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-17

... Access Route Study: The Approaches to San Francisco AGENCY: Coast Guard, DHS. ACTION: Notice of public... the study entitled ``Port Access Route Study: Off San Francisco'' that was published in the Federal... Access Route Study (PARS) to evaluate the continued applicability of and the potential need for...

LARGE SOIL ABSORPTION SYSTEMS FOR WASTEWATERS FROM MULTIPLE-HOME DEVELOPMENTS

EPA Science Inventory

An investigation was conducted to provide insight into the design and performance of large soil absorption systems for treatment and disposal of wastewaters from multiple-home developments. The objectives were to investigate absorption system performance and identify potential de...

Increased Protease-Activated Receptor-2 (PAR-2) Expression on CD14++CD16+ Peripheral Blood Monocytes of Patients with Severe Asthma

PubMed Central

Shrestha Palikhe, Nami; Nahirney, Drew; Laratta, Cheryl; Gandhi, Vivek Dipak; Vethanayagam, Dilini; Bhutani, Mohit; Mayers, Irvin

2015-01-01

Background Protease-Activated Receptor-2 (PAR-2), a G protein coupled receptor activated by serine proteases, is widely expressed in humans and is involved in inflammation. PAR-2 activation in the airways plays an important role in the development of allergic airway inflammation. PAR-2 expression is known to be upregulated in the epithelium of asthmatic subjects, but its expression on immune and inflammatory cells in patients with asthma has not been studied. Methods We recruited 12 severe and 24 mild/moderate asthmatics from the University of Alberta Hospital Asthma Clinics and collected baseline demographic information, medication use and parameters of asthma severity. PAR-2 expression on blood inflammatory cells was analyzed by flow cytometry. Results Subjects with severe asthma had higher PAR-2 expression on CD14++CD16+ monocytes (intermediate monocytes) and also higher percentage of CD14++CD16+PAR-2+ monocytes (intermediate monocytes expressing PAR-2) in blood compared to subjects with mild/moderate asthma. Receiver operating characteristics (ROC) curve analysis showed that the percent of CD14++CD16+PAR-2+ in peripheral blood was able to discriminate between patients with severe and those with mild/moderate asthma with high sensitivity and specificity. In addition, among the whole populations, subjects with a history of asthma exacerbations over the last year had higher percent of CD14++CD16+ PAR-2+ cells in peripheral blood compared to subjects without exacerbations. Conclusions PAR-2 expression is increased on CD14++CD16+ monocytes in the peripheral blood of subjects with severe asthma and may be a biomarker of asthma severity. Our data suggest that PAR-2 -mediated activation of CD14++CD16+ monocytes may play a role in the pathogenesis of severe asthma. PMID:26658828

Control of cleavage spindle orientation in Caenorhabditis elegans: The role of the genes par-2 and par-3

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

Cheng, N.N.; Kirby, C.M.; Kemphues, K.J.

1995-02-01

Polarized asymmetric divisions play important roles in the development of plants and animals. The first two embryonic cleavages of Caenorhabditis elegans provide an opportunity to study the mechanisms controlling polarized asymmetric divisions. The first cleavage is unequal, producing daughters with different sizes and fates. The daughter blastomeres divide with different orientations at the second cleavage; the anterior blastomere divides equally across the long axis of the egg, whereas the posterior blastomere divides unequally along the long axis. We report here the results of our analysis of the genes par-2 and par-3 with respect to their contribution to the polarity ofmore » these divisions. Strong loss-of-function mutations in both genes lead to an equal first cleavage and an altered second cleavage. Interestingly, the mutations exhibit striking gene-specific differences at the second cleavage. The par-2 mutations lead to transverse spindle orientations in both blastomeres, whereas par-3 mutations lead to longitudinal spindle orientations in both blastomeres. The spindle orientation defects correlate with defects in centrosome movements during both the first and the second cell cycle. Temperature shift experiments with par-2 (it5ts) indicate that the par-2(+) activity is not required after the two-cell stage. Analysis of double mutants shows that par-3 is epistatic to par-2. We propose a model wherein par-2(+) and par-3(+) act in concert during the first cell cycle to affect asymmetric modification of the cytoskeleton. This polar modification leads to different behaviors of centrosomes in the anterior and posterior and leads ultimately to blastomere-specific spindle orientations at the second cleavage. 44 refs., 5 figs., 5 tabs.« less

Increased Protease-Activated Receptor-2 (PAR-2) Expression on CD14++CD16+ Peripheral Blood Monocytes of Patients with Severe Asthma.

PubMed

Shrestha Palikhe, Nami; Nahirney, Drew; Laratta, Cheryl; Gandhi, Vivek Dipak; Vethanayagam, Dilini; Bhutani, Mohit; Mayers, Irvin; Cameron, Lisa; Vliagoftis, Harissios

2015-01-01

Protease-Activated Receptor-2 (PAR-2), a G protein coupled receptor activated by serine proteases, is widely expressed in humans and is involved in inflammation. PAR-2 activation in the airways plays an important role in the development of allergic airway inflammation. PAR-2 expression is known to be upregulated in the epithelium of asthmatic subjects, but its expression on immune and inflammatory cells in patients with asthma has not been studied. We recruited 12 severe and 24 mild/moderate asthmatics from the University of Alberta Hospital Asthma Clinics and collected baseline demographic information, medication use and parameters of asthma severity. PAR-2 expression on blood inflammatory cells was analyzed by flow cytometry. Subjects with severe asthma had higher PAR-2 expression on CD14++CD16+ monocytes (intermediate monocytes) and also higher percentage of CD14++CD16+PAR-2+ monocytes (intermediate monocytes expressing PAR-2) in blood compared to subjects with mild/moderate asthma. Receiver operating characteristics (ROC) curve analysis showed that the percent of CD14++CD16+PAR-2+ in peripheral blood was able to discriminate between patients with severe and those with mild/moderate asthma with high sensitivity and specificity. In addition, among the whole populations, subjects with a history of asthma exacerbations over the last year had higher percent of CD14++CD16+ PAR-2+ cells in peripheral blood compared to subjects without exacerbations. PAR-2 expression is increased on CD14++CD16+ monocytes in the peripheral blood of subjects with severe asthma and may be a biomarker of asthma severity. Our data suggest that PAR-2 -mediated activation of CD14++CD16+ monocytes may play a role in the pathogenesis of severe asthma.

The role of proteinase 3 (PR3) and the protease-activated receptor-2 (PAR-2) pathway in dendritic cell (DC) maturation of human-DC-like monocytes and murine DC.

PubMed

Jiang, Bo; Grage-Griebenow, Evelin; Csernok, Elena; Butherus, Kristine; Ehlers, Stefan; Gross, Wolfgang L; Holle, Julia U

2010-01-01

The aim of the study was to assess PAR-2 expression on dendritic cell (DC) subsets and other immune cells of Wegener's granulomatosis (WG) patients and healthy controls (HC) and to investigate whether Proteinase 3 (PR3, a serine protease which can activate PAR2) induces maturation of human DC-like monocytes and murine Flt-3 ligand- and GM-CSF-generated DC. Human peripheral blood cells including DC subsets and Flt-3l- and GM-CSF-generated mouse DC were analysed for expression of PAR-2 and DC maturation markers by flow cytometry before and after stimulation with PR3, trypsin, PAR-2 agonist or LPS for 24 h. There was no difference of PAR-2 expression on PMNs, monocytes, lymphocytes and DC between all WG samples and HC. However, in inactive WG, expression of PAR-2 was downregulated on the cell surface of PMNs, monocytes, lymphocytes, and CD11c+DC compared to active WG and HC. PR3 and PAR2-agonists did not induce upregulation of PAR-2 or maturation markers of human DC-like monocytes in WG and HC. Likewise, murine PR3 did not induce upregulation of PAR-2 or maturation markers in murine DC. PAR-2 expression is downregulated on human peripheral blood cells including CD11c+ DC in inactive WG compared to active WG and HC, possibly reflecting a non-activated status of these cells in inactive disease. PR3 and PAR-2- agonists did not induce maturation of human ex vivo DC-like monocytes in WG and HC and of murine DC, suggesting this pathway is not singularly involved in the maturation of these cell subsets.

Paternal age related schizophrenia (PARS): Latent subgroups detected by k-means clustering analysis.

PubMed

Lee, Hyejoo; Malaspina, Dolores; Ahn, Hongshik; Perrin, Mary; Opler, Mark G; Kleinhaus, Karine; Harlap, Susan; Goetz, Raymond; Antonius, Daniel

2011-05-01

Paternal age related schizophrenia (PARS) has been proposed as a subgroup of schizophrenia with distinct etiology, pathophysiology and symptoms. This study uses a k-means clustering analysis approach to generate hypotheses about differences between PARS and other cases of schizophrenia. We studied PARS (operationally defined as not having any family history of schizophrenia among first and second-degree relatives and fathers' age at birth ≥ 35 years) in a series of schizophrenia cases recruited from a research unit. Data were available on demographic variables, symptoms (Positive and Negative Syndrome Scale; PANSS), cognitive tests (Wechsler Adult Intelligence Scale-Revised; WAIS-R) and olfaction (University of Pennsylvania Smell Identification Test; UPSIT). We conducted a series of k-means clustering analyses to identify clusters of cases containing high concentrations of PARS. Two analyses generated clusters with high concentrations of PARS cases. The first analysis (N=136; PARS=34) revealed a cluster containing 83% PARS cases, in which the patients showed a significant discrepancy between verbal and performance intelligence. The mean paternal and maternal ages were 41 and 33, respectively. The second analysis (N=123; PARS=30) revealed a cluster containing 71% PARS cases, of which 93% were females; the mean age of onset of psychosis, at 17.2, was significantly early. These results strengthen the evidence that PARS cases differ from other patients with schizophrenia. Hypothesis-generating findings suggest that features of PARS may include a discrepancy between verbal and performance intelligence, and in females, an early age of onset. These findings provide a rationale for separating these phenotypes from others in future clinical, genetic and pathophysiologic studies of schizophrenia and in considering responses to treatment. Copyright © 2011 Elsevier B.V. All rights reserved.

Family of BODIPY Photocages Cleaved by Single Photons of Visible/Near-Infrared Light.

PubMed

Peterson, Julie A; Wijesooriya, Chamari; Gehrmann, Elizabeth J; Mahoney, Kaitlyn M; Goswami, Pratik P; Albright, Toshia R; Syed, Aleem; Dutton, Andrew S; Smith, Emily A; Winter, Arthur H

2018-06-13

Photocages are light-sensitive chemical protecting groups that provide external control over when, where, and how much of a biological substrate is activated in cells using targeted light irradiation. Regrettably, most popular photocages (e.g., o-nitrobenzyl groups) absorb cell-damaging ultraviolet wavelengths. A challenge with achieving longer wavelength bond-breaking photochemistry is that long-wavelength-absorbing chromophores have shorter excited-state lifetimes and diminished excited-state energies. However, here we report the synthesis of a family of BODIPY-derived photocages with tunable absorptions across the visible/near-infrared that release chemical cargo under irradiation. Derivatives with appended styryl groups feature absorptions above 700 nm, yielding photocages cleaved with the highest known wavelengths of light via a direct single-photon-release mechanism. Photorelease with red light is demonstrated in living HeLa cells, Drosophila S2 cells, and bovine GM07373 cells upon ∼5 min irradiation. No cytotoxicity is observed at 20 μM photocage concentration using the trypan blue exclusion assay. Improved B-alkylated derivatives feature improved quantum efficiencies of photorelease ∼20-fold larger, on par with the popular o-nitrobenzyl photocages (εΦ = 50-100 M -1 cm -1 ), but absorbing red/near-IR light in the biological window instead of UV light.

Magnetic stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace atomic absorption spectrometry.

PubMed

Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa

2015-04-01

A new dispersive liquid-liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 μg L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Ecosystem carbon exchange in Artemisia ordosica shrubland of Ordos Plateau in two different precipitation years].

PubMed

Gao, Li; Dong, Ting-Ting; Wang, Yu-Qing; Yan, Zhi-Jian; Baoyin, Tao-ge-tao; Wang, Hui; Dai, Ya-Ting

2014-08-01

Characteristics of ecosystem carbon exchange and its impact factors in Artemisia ordosica shrubland in 2011 (low precipitation) and 2012 (high precipitation), Ordos Plateau, were studied using eddy covariance methods. The results showed that the diurnal dynamics of ecosystem carbon exchange could be expressed as single-peak and double-peak curves in the two different precipitation years. In 2011, three carbon absorption peaks and three carbon release peaks of ecosystem carbon exchange presented in the growing season. In 2012, four carbon absorption peaks and one carbon release peak appeared in the growing season. The A. ordosica shrubland was a net carbon sink from June to September and a carbon source in October in 2011. In 2012, A. ordosica shrubland was a net carbon sink in the whole growing season. The amount of carbon fixed by A. ordosica shrubland in the growing season in 2012 was 268.90 mg CO2 x m(-2) x s(-1) higher than that in 2011. The ecosystem carbon exchange of A. ordosica shrubland was controlled by PAR (photosynthetically active radiation) on the day scale, and affected by both abiotic (precipitation and soil water content) and biotic (aboveground net primary, productivity) factors on the growing season scale.

[Analysis of inorganic elements in hydroponic Taraxacum mongolicum grown under different spectrum combinations by ICP-AES].

PubMed

Chen, Xiao-li; Morewane, M B; Xue, Xu-zhang; Guo, Wen-zhong; Wang, Li-chun

2015-02-01

Dandelion (Taraxacum mongolicum) was hydroponically cultured in a completely enclosed plant factory, in which fluorescence and LED emitting spectra of different bands were used as the sole light source for plant growth. Effects of spectral component on the growth of dandelion were studied and the contents of ten inorganic elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu and B in dandelion were analyzed by ICP-AES technology. The results showed that: (1) Under the condition of similar photosynthetic active radiation (PAR), single R or combined spectrums of FLRB were beneficial for biomass accumulation, while single B was the contrary; (2) Macroelements content ratio in Taraxacum mongolicum grown under FLwas K:Ca:P:Mg : Na=79.74:32.39:24.32:10.55:1.00, microelements content ratio was Fe:Mn:B:Zn:Cu = 9.28:9.71:3.82:2.08:1.00; (3) Red light (peak at 660 nm) could promote the absorptions of Ca, Fe, Mn, Zn, while absorption of Cu was not closely related to spectral conditions; (4) Thehighest accumulation of Ca, Na, Mn and Zn were obtained in aerial parts of Taraxacum mongolicum plants grown under pure red spectrum R, while the accumulation of the rest six elements reached the highest level under the mixed spectrum FLRB.

From sunlight to phytomass: on the potential efficiency of converting solar radiation to phyto-energy.

PubMed

Amthor, Jeffrey S

2010-12-01

The relationship between solar radiation capture and potential plant growth is of theoretical and practical importance. The key processes constraining the transduction of solar radiation into phyto-energy (i.e. free energy in phytomass) were reviewed to estimate potential solar-energy-use efficiency. Specifically, the out-put:input stoichiometries of photosynthesis and photorespiration in C(3) and C(4) systems, mobilization and translocation of photosynthate, and biosynthesis of major plant biochemical constituents were evaluated. The maintenance requirement, an area of important uncertainty, was also considered. For a hypothetical C(3) grain crop with a full canopy at 30°C and 350 ppm atmospheric [CO(2) ], theoretically potential efficiencies (based on extant plant metabolic reactions and pathways) were estimated at c. 0.041 J J(-1) incident total solar radiation, and c. 0.092 J J(-1) absorbed photosynthetically active radiation (PAR). At 20°C, the calculated potential efficiencies increased to 0.053 and 0.118 J J(-1) (incident total radiation and absorbed PAR, respectively). Estimates for a hypothetical C(4) cereal were c. 0.051 and c. 0.114 J J(-1), respectively. These values, which cannot be considered as precise, are less than some previous estimates, and the reasons for the differences are considered. Field-based data indicate that exceptional crops may attain a significant fraction of potential efficiency. © The Author (2010). Journal compilation © New Phytologist Trust (2010).

Activation of PAR-2 elicits NO-dependent and CGRP-independent dilation of the dural artery.

PubMed

Bhatt, Deepak K; Ploug, Kenneth B; Ramachandran, Roshni; Olesen, Jes; Gupta, Saurabh

2010-06-01

The goal of this study was to determine the vascular effects of protease-activated receptor-2 (PAR-2) activation in the rat cranial vasculature. The role of PAR-2 in pain and inflammatory conditions has been established but the information available on its effects and receptor distribution in the trigeminal vascular axis is limited. We studied the dilatory function and expression of PAR-2 in the neuro-vascular circuit, critical in migraine pathogenesis. We also investigated the interaction of PAR-2 with calcitonin gene-related peptide (CGRP) and dural mast cells. We used an improved model of intravital microscopy on the closed cranial window in rats to study the vascular effects of PAR-2 activating peptides (PAR-2 APs; SLIGRL-NH(2), 2-Furoyl-LIGRLO-NH(2)) in the dural vasculature. Measurement of immunoreactive CGRP in skull halves and in trigeminal nucleus caudalis was done by using an enzyme-linked immunosorbent assay. We also analyzed the presence of PAR-2 in different migraine relevant tissues by quantitative real-time PCR and Western blot analysis. PAR-2 APs and trypsin induced a dose-dependent increase in dural artery diameter. The topical application of a nonspecific nitric oxide synthase (NOS) inhibitor, L-N(G)-Nitroarginine methyl ester, attenuated SLIGRL-NH(2) responses. Olcegepant, a CGRP receptor antagonist, did not a have significant effect on the SLIGRL-NH(2) responses, though exogenous CGRP responses were completely blocked. There was no significant release of CGRP from skull halves incubated with SLIGRL-NH(2) as compared with those incubated with the corresponding negative peptide. Chronic mast cell degranulation did not change the vascular effects of PAR-2 APs. mRNA and protein expression of PAR-2 were found throughout trigeminovasuclar axis. PAR-2 activation leads to vasodilation of dural arteries and these responses are partially mediated by nitric oxide. As PAR-2 is present throughout trigeminovasuclar axis, it may have a role in migraine pathogenesis, independent of CGRP and mast cell mediated mechanism.

Proteinase-activated receptor 4 stimulation-induced epithelial-mesenchymal transition in alveolar epithelial cells

PubMed Central

Ando, Seijitsu; Otani, Hitomi; Yagi, Yasuhiro; Kawai, Kenzo; Araki, Hiromasa; Fukuhara, Shirou; Inagaki, Chiyoko

2007-01-01

Background Proteinase-activated receptors (PARs; PAR1–4) that can be activated by serine proteinases such as thrombin and neutrophil catepsin G are known to contribute to the pathogenesis of various pulmonary diseases including fibrosis. Among these PARs, especially PAR4, a newly identified subtype, is highly expressed in the lung. Here, we examined whether PAR4 stimulation plays a role in the formation of fibrotic response in the lung, through alveolar epithelial-mesenchymal transition (EMT) which contributes to the increase in myofibroblast population. Methods EMT was assessed by measuring the changes in each specific cell markers, E-cadherin for epithelial cell, α-smooth muscle actin (α-SMA) for myofibroblast, using primary cultured mouse alveolar epithelial cells and human lung carcinoma-derived alveolar epithelial cell line (A549 cells). Results Stimulation of PAR with thrombin (1 U/ml) or a synthetic PAR4 agonist peptide (AYPGKF-NH2, 100 μM) for 72 h induced morphological changes from cobblestone-like structure to elongated shape in primary cultured alveolar epithelial cells and A549 cells. In immunocytochemical analyses of these cells, such PAR4 stimulation decreased E-cadherin-like immunoreactivity and increased α-SMA-like immunoreactivity, as observed with a typical EMT-inducer, tumor growth factor-β (TGF-β). Western blot analyses of PAR4-stimulated A549 cells also showed similar changes in expression of these EMT-related marker proteins. Such PAR4-mediated changes were attenuated by inhibitors of epidermal growth factor receptor (EGFR) kinase and Src. PAR4-mediated morphological changes in primary cultured alveolar epithelial cells were reduced in the presence of these inhibitors. PAR4 stimulation increased tyrosine phosphorylated EGFR or tyrosine phosphorylated Src level in A549 cells, and the former response being inhibited by Src inhibitor. Conclusion PAR4 stimulation of alveolar epithelial cells induced epithelial-mesenchymal transition (EMT) as monitored by cell shapes, and epithelial or myofibroblast marker at least partly through EGFR transactivation via receptor-linked Src activation. PMID:17433115

Pharmacodynamics of levofloxacin against characterized ciprofloxacin-resistant Streptococcus pneumoniae.

PubMed

Lister, Philip D

2008-09-01

In a previous study, levofloxacin 750 mg eradicated 4 ciprofloxacin-resistant isolates of Streptococcus pneumoniae from an in vitro pharmacodynamic model (IVPM). However, quinolone resistance-determining region (QRDR) mutations were not detected among those isolates. This study further evaluates levofloxacin 500 mg and 750 mg against S pneumoniae strains with characterized QRDR mutations. Six isolates with levofloxacin minimum inhibitory concentrations (MICs) of 2 to 4 microg/mL were selected for this study. Strains 5401, 5409, and 5437 contained only parC mutations. Three additional strains contained 2 mutations each: strain 5429 (parC and parE ), strain 5442 (parC and gyrA), and strain 5445 (parC and gyrB). Logarithmic-phase cultures (approximately 1 x 10(7) CFU/mL) were inoculated into the peripheral compartment of the IVPM and exposed to peak free-drug concentrations achieved with levofloxacin 500 mg and 750 mg (PO) and ciprofloxacin 750 mg (PO). Elimination pharmacokinetics were simulated and changes in viable counts were measured over 30 h. Ciprofloxacin exhibited very little antibacterial activity against the 6 strains, while levofloxacin 750 mg rapidly killed and eradicated the 3 parC mutant strains and the dual parC/parE mutant strains. Although levofloxacin 500 mg initially decreased viable counts by 4.5 to 6 logs, inoculum regrowth was observed between 12 and 24 h for the 6 strains. Regrowth was not due to the selection of mutant subpopulations. The pharmacodynamics of both levofloxacin doses were substantially diminished against the 2 strains with dual mutations in both parC and gyrA/B. The rapid eradication of single parC and dual parC/parE mutants with levofloxacin 750 mg demonstrates that this dose may slow the emergence of resistance due to these mutations. The decreased efficacy of both levofloxacin doses against the double parC and gyrA/B mutants highlights the importance of preventing the development and spread of double mutants.

Energy-absorption spectroscopy of unitary Fermi gases in a uniform potential

NASA Astrophysics Data System (ADS)

Zhang, Pengfei; Yu, Zhenhua

2018-04-01

We propose to use the energy absorption spectroscopy to measure the kinetic coefficients of unitary Fermi gases in a uniform potential. We show that, in our scheme, the energy absorption spectrum is proportional to the dynamic structure factor of the system. The profile of the spectrum depends on the shear viscosity η , the thermal conductivity κ , and the superfluid bulk viscosity ξ3. We show that extraction of these coefficients from the spectrum is achievable in present experiments.

Effect of PAR-2 Deficiency in Mice on KC Expression after Intratracheal LPS Administration

PubMed Central

Williams, Julie C.; Lee, Rebecca D.; Doerschuk, Claire M.; Mackman, Nigel

2011-01-01

Protease activated receptors (PAR) have been shown to play a role in inflammation. PAR-2 is expressed by numerous cells in the lung and has either proinflammatory, anti-inflammatory, or no effect depending on the model. Here, we examined the role of PAR-2 in a model of LPS-induced lung inflammation. We found that PAR-2-deficient mice had significantly less KC expression in bronchial lavage fluid compared with wild-type mice but there was no difference in MIP-2 or TNF-α expression. We also found that isolated alveolar and resident peritoneal macrophages lacking PAR-2 showed a similar deficit in KC after LPS stimulation without differences in MIP-2 or TNF-α. Infiltration of neutrophils and macrophages into the lung following LPS administration was not affected by an absence of PAR-2. Our results support the notion that PAR-2 plays a role in LPS activation of TLR4 signaling in macrophages. PMID:22175012

Effect of PAR-2 Deficiency in Mice on KC Expression after Intratracheal LPS Administration.

PubMed

Williams, Julie C; Lee, Rebecca D; Doerschuk, Claire M; Mackman, Nigel

2011-01-01

Protease activated receptors (PAR) have been shown to play a role in inflammation. PAR-2 is expressed by numerous cells in the lung and has either proinflammatory, anti-inflammatory, or no effect depending on the model. Here, we examined the role of PAR-2 in a model of LPS-induced lung inflammation. We found that PAR-2-deficient mice had significantly less KC expression in bronchial lavage fluid compared with wild-type mice but there was no difference in MIP-2 or TNF-α expression. We also found that isolated alveolar and resident peritoneal macrophages lacking PAR-2 showed a similar deficit in KC after LPS stimulation without differences in MIP-2 or TNF-α. Infiltration of neutrophils and macrophages into the lung following LPS administration was not affected by an absence of PAR-2. Our results support the notion that PAR-2 plays a role in LPS activation of TLR4 signaling in macrophages.

PAR(2) and temporomandibular joint inflammation in the rat.

PubMed

Denadai-Souza, A; Cenac, N; Casatti, C A; Câmara, P R de Souza; Yshii, L M; Costa, S K P; Vergnolle, N; Muscará, M N

2010-10-01

The proteinase-activated receptor 2 (PAR(2)) is a putative therapeutic target for arthritis. We hypothesized that the early pro-inflammatory effects secondary to its activation in the temporomandibular joint (TMJ) are mediated by neurogenic mechanisms. Immunofluorescence analysis revealed a high degree of neurons expressing PAR(2) in retrogradely labeled trigeminal ganglion neurons. Furthermore, PAR(2) immunoreactivity was observed in the lining layer of the TMJ, co-localizing with the neuronal marker PGP9.5 and substance-P-containing peripheral sensory nerve fibers. The intra-articular injection of PAR(2) agonists into the TMJ triggered a dose-dependent increase in plasma extravasation, neutrophil influx, and induction of mechanical allodynia. The pharmacological blockade of natural killer 1 (NK(1)) receptors abolished PAR(2)-induced plasma extravasation and inhibited neutrophil influx and mechanical allodynia. We conclude that PAR(2) activation is pro-inflammatory in the TMJ, through a neurogenic mechanism involving NK(1) receptors. This suggests that PAR(2) is an important component of innate neuro-immune response in the rat TMJ.

Tiam1 interaction with the PAR complex promotes talin-mediated Rac1 activation during polarized cell migration

PubMed Central

Wang, Shujie; Watanabe, Takashi; Matsuzawa, Kenji; Katsumi, Akira; Kakeno, Mai; Matsui, Toshinori; Ye, Feng; Sato, Kazuhide; Murase, Kiyoko; Sugiyama, Ikuko; Kimura, Kazushi; Mizoguchi, Akira; Ginsberg, Mark H.; Collard, John G.

2012-01-01

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration. PMID:23071154

Characterization of a point mutation in the parC gene of Mycoplasma bovirhinis associated with fluoroquinolone resistance.

PubMed

Hirose, K; Kawasaki, Y; Kotani, K; Abiko, K; Sato, H

2004-05-01

Quinolone-resistant (QR) mutants of Mycoplasma bovirhinis strain PG43 (type strain) were generated by stepwise selection in increasing concentrations of enrofloxacin (ENR). An alteration was found in the quinolone resistance-determining region (QRDR) of the parC gene coding for the ParC subunit of topoisomerase IV from these mutants, but not in the gyrA, gyrB, and parE gene coding for the GyrA and GyrB subunits of DNA gyrase and the ParE subunit of topoisomerase IV. Similarly, such an alteration in QRDR of parC was found in the field isolates of M. bovirhinis, which possessed various levels of QR. The substitution of leucine (Leu) by serine (Ser) at position 80 of QRDR of ParC was observed in both QR-mutants and QR-isolates. This is the first report of QR based on a point mutation of the parC gene in M. bovirhinis.

Police accident report forms: safety device coding and enacted laws.

PubMed

Brock, K; Lapidus, G

2008-12-01

Safety device coding on state police accident report (PAR) forms was compared with provisions in state traffic safety laws. PAR forms were obtained from all 50 states and the District of Columbia (states/DC). For seat belts, 22 states/DC had a primary seat belt enforcement law vs 50 with a PAR code. For car seats, all 51 states/DC had a law and a PAR code. For booster seats, 39 states/DC had a law vs nine with a PAR code. For motorcycle helmets, 21 states/DC had an all-age rider helmet law and another 26 a partial-age law vs 50 with a PAR code. For bicycle helmets, 21 states/DC had a partial-age rider helmet law vs 48 with a PAR code. Therefore gaps in the ability of states to fully record accident data reflective of existing state traffic safety laws are revealed. Revising the PAR forms in all states to include complete variables for safety devices should be an important priority, independent of the laws.

Differential roles of kallikrein-related peptidase 6 in malignant transformation and ΔNp63β-mediated epithelial-mesenchymal transition of oral squamous cell carcinoma.

PubMed

Kaneko, Naoki; Kawano, Shintaro; Yasuda, Kaori; Hashiguchi, Yuma; Sakamoto, Taiki; Matsubara, Ryota; Goto, Yuichi; Jinno, Teppei; Maruse, Yasuyuki; Morioka, Masahiko; Hattori, Taichi; Tanaka, Shoichi; Tanaka, Hideaki; Kiyoshima, Tamotsu; Nakamura, Seiji

2017-12-01

We previously reported that epithelial-to-mesenchymal transition (EMT) was mediated by ΔNp63β in oral squamous cell carcinoma (OSCC). In this study, DNA microarray analyses were performed using ΔNp63β-overexpressing OSCC cells to identify genes associated with ΔNp63β-mediated EMT. Thereby, we focused on kallikrein-related peptidase (KLK) 6, most up-regulated following ΔNp63β-overexpression, that activates protease-activated receptors (PARs). In RT-PCR analyses, ΔNp63 was positively associated with KLK6 and PAR2 and negatively with PAR1 in OSCC cells. By ΔNp63 knockdown, KLK6 and PAR2 expression was decreased and PAR1 was increased. Furthermore, KLK6 knockdown led to enhancing migration and invasion, and inhibiting proliferation, suggesting EMT-phenotypes. Although, in the KLK6 or PAR2 knockdown cells, phosphorylation of ERK was reduced, it was restored in the KLK6 knockdown OSCC cells treated with recombinant KLK6 proteins. Immunohistochemistry showed ΔNp63, KLK6, and PAR2 were more strongly expressed in the epithelial dysplasia and central region of OSCC than normal oral epithelium, whereas PAR1 expression was undetectable. Interestingly, at the invasive front of OSCC, ΔNp63, KLK6, and PAR2 were reduced, but PAR1 was elevated. In addition, the OSCC patients with decreasing KLK6 expression at the invasive front had more unfavourable prognosis. These results suggested differential roles of KLK6 in malignant transformation and EMT; high ΔNp63β expression up-regulates KLK6-PAR2 and down-regulates PAR1, inducing malignant transformation in oral epithelium with stimulating proliferation through ERK signal activation. Moreover, KLK6-PAR2 expression is down-regulated and PAR1 is up-regulated when ΔNp63β expression is decreased, leading to EMT with enhancing migration and invasion through ERK signal reduction at the invasive front. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Spatiotemporal characteristics of photosynthetically active radiation in understory of Korean pine and broadleaved mixed forest in Changbai Mountains].

PubMed

Yuan, Feng-Hui; Guan, De-Xin; Wu, Jia-Bing; Wang, An-Zhi; Shi, Ting-Ting; Zhang, Xiao-Jing

2008-02-01

Based on the data of three years successive automatic measurement with five horizontal quantum PAR sensors, this paper studied the spatiotemporal characteristics of photosynthetically active radiation (PAR) in the understory of Korean pine and broadleaved mixed forest in Changbai Mountains, in contrast with above-canopy PAR. It was found that the annual dynamics of above-canopy PAR showed two or more peaks, which was mainly affected by the weather conditions such as cloudy, foggy and rainy events. The annual dynamics of understory PAR followed the same trend of above-canopy PAR in non-growth season, but was steady and lower in numerical value in growth season. On clear days, larger differences were observed in the diurnal variation and frequency distribution of the understory PAR. As for the spatial variation of the understory PAR, the coefficient of variation (CV) was smaller in non-growth season (about 0.15) than in growth season (> 0.22), with the greatest in August. On the clear days in growth season, the understory PAR had a greater spatial variation when the solar elevation angle was between 38 degrees and 48 degrees (at 9:00-10:00 or 13:00-14:00).

Full-length soluble urokinase plasminogen activator receptor down-modulates nephrin expression in podocytes

PubMed Central

Alfano, Massimo; Cinque, Paola; Giusti, Guido; Proietti, Silvia; Nebuloni, Manuela; Danese, Silvio; D’Alessio, Silvia; Genua, Marco; Portale, Federica; Lo Porto, Manuela; Singhal, Pravin C.; Rastaldi, Maria Pia; Saleem, Moin A.; Mavilio, Domenico; Mikulak, Joanna

2015-01-01

Increased plasma level of soluble urokinase-type plasminogen activator receptor (suPAR) was associated recently with focal segmental glomerulosclerosis (FSGS). In addition, different clinical studies observed increased concentration of suPAR in various glomerular diseases and in other human pathologies with nephrotic syndromes such as HIV and Hantavirus infection, diabetes and cardiovascular disorders. Here, we show that suPAR induces nephrin down-modulation in human podocytes. This phenomenon is mediated only by full-length suPAR, is time-and dose-dependent and is associated with the suppression of Wilms’ tumor 1 (WT-1) transcription factor expression. Moreover, an antagonist of αvβ3 integrin RGDfv blocked suPAR-induced suppression of nephrin. These in vitro data were confirmed in an in vivo uPAR knock out Plaur−/− mice model by demonstrating that the infusion of suPAR inhibits expression of nephrin and WT-1 in podocytes and induces proteinuria. This study unveiled that interaction of full-length suPAR with αvβ3 integrin expressed on podocytes results in down-modulation of nephrin that may affect kidney functionality in different human pathologies characterized by increased concentration of suPAR. PMID:26380915

Effects of tissue factor, PAR-2 and MMP-9 expression on human breast cancer cell line MCF-7 invasion.

PubMed

Lin, Zeng-Mao; Zhao, Jian-Xin; Duan, Xue-Ning; Zhang, Lan-Bo; Ye, Jing-Ming; Xu, Ling; Liu, Yin-Hua

2014-01-01

This study aimed to explore the expression of tissue factor (TF), protease activated receptor-2 (PAR-2), and matrix metalloproteinase-9 (MMP-9) in the MCF-7 breast cancer cell line and influence on invasiveness. Stable MCF-7 cells transfected with TF cDNA and with TF ShRNA were established. TF, PAR-2, and MMP-9 protein expression was analyzed using indirect immunofluorescence and invasiveness was evaluated using a cell invasion test. Effects of an exogenous PAR-2 agonist were also examined. TF protein expression significantly differed between the TF cDNA and TF ShRNA groups. MMP-9 protein expression was significantly correlated with TF protein expression, but PAR-2 protein expression was unaffected. The PAR- 2 agonist significantly enhanced MMP-9 expression and slightly increased TF and PAR-2 expression in the TF ShRNA group, but did not significantly affect protein expression in MCF-7 cells transfected with TF cDNA. TF and MMP-9 expression was positively correlated with the invasiveness of tumor cells. TF, PAR-2, and MMP-9 affect invasiveness of MCF-7 cells. TF may increase MMP-9 expression by activating PAR-2.

Role of thrombin signalling in platelets in haemostasis and thrombosis

NASA Astrophysics Data System (ADS)

Sambrano, Gilberto R.; Weiss, Ethan J.; Zheng, Yao-Wu; Huang, Wei; Coughlin, Shaun R.

2001-09-01

Platelets are critical in haemostasis and in arterial thrombosis, which causes heart attacks and other events triggered by abnormal clotting. The coagulation protease thrombin is a potent activator of platelets ex vivo. However, because thrombin also mediates fibrin deposition and because multiple agonists can trigger platelet activation, the relative importance of platelet activation by thrombin in haemostasis and thrombosis is unknown. Thrombin triggers cellular responses at least in part through protease-activated receptors (PARs). Mouse platelets express PAR3 and PAR4 (ref. 9). Here we show that platelets from PAR4-deficient mice failed to change shape, mobilize calcium, secrete ATP or aggregate in response to thrombin. This result demonstrates that PAR signalling is necessary for mouse platelet activation by thrombin and supports the model that mouse PAR3 (mPAR3) does not by itself mediate transmembrane signalling but instead acts as a cofactor for thrombin cleavage and activation of mPAR4 (ref. 10). Importantly, PAR4-deficient mice had markedly prolonged bleeding times and were protected in a model of arteriolar thrombosis. Thus platelet activation by thrombin is necessary for normal haemostasis and may be an important target in the treatment of thrombosis.

Neo-Positivist Intrusions, Post-Qualitative Challenges, and PAR's Generative Indeterminacies

ERIC Educational Resources Information Center

Miller, Janet L.

2017-01-01

Although committed to PAR's overarching aspirations, many advocates also have noted myriad complexities of engaging in PAR, where ambiguities and disarrays--all kinds of inconclusive evidence--can proliferate. Uncertainties especially can erupt if PAR education-focused projects are positioned, oxymoronically, as expected to produce "high…

Accurate spectroscopic redshift of the multiply lensed quasar PSOJ0147 from the Pan-STARRS survey

NASA Astrophysics Data System (ADS)

Lee, C.-H.

2017-09-01

Context. The gravitational lensing time delay method provides a one-step determination of the Hubble constant (H0) with an uncertainty level on par with the cosmic distance ladder method. However, to further investigate the nature of the dark energy, a H0 estimate down to 1% level is greatly needed. This requires dozens of strongly lensed quasars that are yet to be delivered by ongoing and forthcoming all-sky surveys. Aims: In this work we aim to determine the spectroscopic redshift of PSOJ0147, the first strongly lensed quasar candidate found in the Pan-STARRS survey. The main goal of our work is to derive an accurate redshift estimate of the background quasar for cosmography. Methods: To obtain timely spectroscopically follow-up, we took advantage of the fast-track service programme that is carried out by the Nordic Optical Telescope. Using a grism covering 3200-9600 Å, we identified prominent emission line features, such as Lyα, N V, O I, C II, Si IV, C IV, and [C III] in the spectra of the background quasar of the PSOJ0147 lens system. This enables us to determine accurately the redshift of the background quasar. Results: The spectrum of the background quasar exhibits prominent absorption features bluewards of the strong emission lines, such as Lyα, N V, and C IV. These blue absorption lines indicate that the background source is a broad absorption line (BAL) quasar. Unfortunately, the BAL features hamper an accurate determination of redshift using the above-mentioned strong emission lines. Nevertheless, we are able to determine a redshift of 2.341 ± 0.001 from three of the four lensed quasar images with the clean forbidden line [C III]. In addition, we also derive a maximum outflow velocity of 9800 km s-1 with the broad absorption features bluewards of the C IV emission line. This value of maximum outflow velocity is in good agreement with other BAL quasars.

Transient early neurotrophin release and delayed inflammatory cytokine release by microglia in response to PAR-2 stimulation

PubMed Central

2012-01-01

Activated microglia exerts both beneficial and deleterious effects on neurons, but the signaling mechanism controlling these distinct responses remain unclear. We demonstrated that treatment of microglial cultures with the PAR-2 agonist, 2-Furoyl-LIGRLO-NH2, evoked early transient release of BDNF, while sustained PAR-2 stimulation evoked the delayed release of inflammatory cytokines (IL-1β and TNF-α) and nitric oxide. Culture medium harvested during the early phase (at 1 h) of microglial activation induced by 2-Furoyl-LIGRLO-NH2 (microglial conditioned medium, MCM) had no deleterious effects on cultured neurons, while MCM harvested during the late phase (at 72 h) promoted DNA fragmentation and apoptosis as indicated by TUNEL and annexin/PI staining. Blockade of PAR-1 during the early phase of PAR-2 stimulation enhanced BDNF release (by 11%, small but significant) while a PAR-1 agonist added during the late phase (24 h after 2-Furoyl-LIGRLO-NH2 addition) suppressed the release of cytokines and NO. The neuroprotective and neurotoxic effects of activated microglial exhibit distinct temporal profiles that are regulated by PAR-1 and PAR-2 stimulation. It may be possible to facilitate neuronal recovery and repair by appropriately timed stimulation and inhibition of microglial PAR-1 and PAR-2 receptors. PMID:22731117

Tryptase - PAR2 axis in Experimental Autoimmune Prostatitis, a model for Chronic Pelvic Pain Syndrome

PubMed Central

Roman, Kenny; Done, Joseph D.; Schaeffer, Anthony J.; Murphy, Stephen F.; Thumbikat, Praveen

2014-01-01

Chronic prostatitis/Chronic pelvic pain syndrome (CP/CPPS) affects up to 15% of the male population and is characterized by pelvic pain. Mast cells are implicated in the murine experimental autoimmune prostatitis (EAP) model as key to chronic pelvic pain development. The mast cell mediator tryptase-β and its cognate receptor protease-activated receptor 2 (PAR2) are involved in mediating pain in other visceral disease models. Prostatic secretions and urines from CP/CPPS patients were examined for the presence of mast cell degranulation products. Tryptase-β and PAR2 expression were examined in murine experimental autoimmune prostatitis (EAP). Pelvic pain and inflammation were assessed in the presence or absence of PAR2 expression and upon PAR2 neutralization. Tryptase-β and carboxypeptidase A3 were elevated in CP/CPPS compared to healthy volunteers. Tryptase-β was capable of inducing pelvic pain and was increased in EAP along with its receptor PAR2. PAR2 was required for the development of chronic pelvic pain in EAP. PAR2 signaling in dorsal root ganglia lead to ERK1/2 phosphorylation and calcium influx. PAR2 neutralization using antibodies attenuated chronic pelvic pain in EAP. The tryptase-PAR2 axis is an important mediator of pelvic pain in EAP and may play a role in the pathogenesis of CP/CPPS. PMID:24726923

PAR-2, IL-4R, TGF-β and TNF-α in bronchoalveolar lavage distinguishes extrinsic allergic alveolitis from sarcoidosis.

PubMed

Matěj, Radoslav; Smětáková, Magdalena; Vašáková, Martina; Nováková, Jana; Sterclová, Martina; Kukal, Jaromír; Olejár, Tomáš

2014-08-01

Sarcoidosis (SARC) and extrinsic allergic alveolitis (EAA) share certain markers, making a differential diagnosis difficult even with histopathological investigation. In lung tissue, proteinase-activated receptor-2 (PAR-2) is primarily investigated with regard to epithelial and inflammatory perspectives. Varying levels of certain chemokines can be a useful tool for distinguishing EAA and SARC. Thus, in the present study, differences in the levels of transforming growth factor (TGF)-β1, tumor necrosis factor (TNF)-α, interleukin-4 receptor (IL-4R) and PAR-2 in bronchoalveolar lavage fluid (BALF) were compared, using an ELISA method, between 14 patients with EAA and six patients with SARC. Statistically significant higher levels of IL-4R, PAR-2 and the PAR-2/TGF-β1 and PAR-2/TNF-α ratios were observed in EAA patients as compared with SARC patients. Furthermore, the ratios of TNF-α/total protein, TGF-β1/PAR-2 and TNF-α/PAR-2 were significantly lower in EAA patients than in SARC patients. The results indicated a higher detection of PAR-2 in EAA samples in association with TNF-α and TGF-β levels. As EAA and PAR-2 in parallel belong to the Th2-mediated pathway, the results significantly indicated an association between this receptor and etiology. In addition, the results indicated that SARC is predominantly a granulomatous inflammatory disease, thus, higher levels of TNF-α are observed. Therefore, the detection of PAR-2 and investigated chemokines in BALF may serve as a useful tool in the differential diagnosis between EAA and SARC.

A Neural Network Model for K(λ) Retrieval and Application to Global K par Monitoring

PubMed Central

Chen, Jun; Zhu, Yuanli; Wu, Yongsheng; Cui, Tingwei; Ishizaka, Joji; Ju, Yongtao

2015-01-01

Accurate estimation of diffuse attenuation coefficients in the visible wavelengths K d(λ) from remotely sensed data is particularly challenging in global oceanic and coastal waters. The objectives of the present study are to evaluate the applicability of a semi-analytical K d(λ) retrieval model (SAKM) and Jamet’s neural network model (JNNM), and then develop a new neural network K d(λ) retrieval model (NNKM). Based on the comparison of K d(λ) predicted by these models with in situ measurements taken from the global oceanic and coastal waters, all of the NNKM, SAKM, and JNNM models work well in K d(λ) retrievals, but the NNKM model works more stable and accurate than both SAKM and JNNM models. The near-infrared band-based and shortwave infrared band-based combined model is used to remove the atmospheric effects on MODIS data. The K d(λ) data was determined from the atmospheric corrected MODIS data using the NNKM, JNNM, and SAKM models. The results show that the NNKM model produces <30% uncertainty in deriving K d(λ) from global oceanic and coastal waters, which is 4.88-17.18% more accurate than SAKM and JNNM models. Furthermore, we employ an empirical approach to calculate K par from the NNKM model-derived diffuse attenuation coefficient at visible bands (443, 488, 555, and 667 nm). The results show that our model presents a satisfactory performance in deriving K par from the global oceanic and coastal waters with 20.2% uncertainty. The K par are quantified from MODIS data atmospheric correction using our model. Comparing with field measurements, our model produces ~31.0% uncertainty in deriving K par from Bohai Sea. Finally, the applicability of our model for general oceanographic studies is briefly illuminated by applying it to climatological monthly mean remote sensing reflectance for time ranging from July, 2002- July 2014 at the global scale. The results indicate that the high K d(λ) and K par values are usually found around the coastal zones in the high latitude regions, while low K d(λ) and K par values are usually found in the open oceans around the low-latitude regions. These results could improve our knowledge about the light field under waters at either the global or basin scales, and be potentially used into general circulation models to estimate the heat flux between atmosphere and ocean. PMID:26083341

CONTROL OF SULFUR EMISSIONS FROM OIL SHALE RETORTING USING SPEND SHALE ABSORPTION

EPA Science Inventory

The paper gives results of a detailed engineering evaluation of the potential for using an absorption on spent shale process (ASSP) for controlling sulfur emissions from oil shale plants. The evaluation analyzes the potential effectiveness and cost of absorbing SO2 on combusted s...

Binding of anti-SSA antibodies to apoptotic fetal cardiocytes stimulates urokinase plasminogen activator (uPA)/uPA receptor-dependent activation of TGF-β and potentiates fibrosis.

PubMed

Briassouli, Paraskevi; Rifkin, Daniel; Clancy, Robert M; Buyon, Jill P

2011-11-15

In congenital heart block (CHB), binding of maternal anti-SSA/Ro Abs to fetal apoptotic cardiocytes impairs their removal by healthy cardiocytes and increases urokinase plasminogen activator (uPA)/uPA receptor (uPAR)-dependent plasmin activation. Because the uPA/uPAR system plays a role in TGF-β activation, we evaluated whether anti-Ro binding to apoptotic cardiocytes enhances plasmin-mediated activation of TGF-β, thereby promoting a profibrosing phenotype. Supernatants from cocultures of healthy cardiocytes and apoptotic cardiocytes bound by IgG from a mother whose child had CHB (apoptotic-CHB-IgG [apo-CHB-IgG]) exhibited significantly increased levels of active TGF-β compared with supernatants from cocultures of healthy cardiocytes and apoptotic cardiocytes preincubated with IgG from a healthy donor. Treatment of the culture medium with anti-TGF-β Ab or TGF-β inhibitor (SB431542) abrogated the luciferase response, thereby confirming TGF-β dependency. Increased uPA levels and activity were present in supernatants generated from cocultures of healthy cardiocytes and apo-CHB-IgG cardiocytes compared with healthy cardiocytes and apoptotic cardiocytes preincubated with IgG from a healthy donor, respectively. Treatment of apo-CHB-IgG cardiocytes with anti-uPAR or anti-uPA Abs or plasmin inhibitor aprotinin prior to coculturing with healthy cardiocytes attenuated TGF-β activation. Supernatants derived from cocultures of healthy cardiocytes and apo-CHB-IgG cardiocytes promoted Smad2 phosphorylation and fibroblast transdifferentiation, as evidenced by increased smooth muscle actin and collagen expression, which decreased when fibroblasts were treated with supernatants from cocultures pretreated with uPAR Abs. These data suggested that binding of anti-Ro Abs to apoptotic cardiocytes triggers TGF-β activation, by virtue of increasing uPAR-dependent uPA activity, thus initiating and amplifying a cascade of events that promotes myofibroblast transdifferentiation and scar.

Predictors of transition to heroin use among initially non-opioid dependent illicit pharmaceutical opioid users: A natural history study

PubMed Central

Carlson, Robert G.; Nahhas, Ramzi W.; Martins, Silvia S.; Daniulaityte, Raminta

2016-01-01

Background Increases in illicit pharmaceutical opioid (PO) use have been associated with risk for transition to heroin use. We identify predictors of transition to heroin use among young, illicit PO users with no history of opioid dependence or heroin use at baseline. Methods Respondent-driven sampling recruited 383 participants; 362 returned for at least one biannual structured interview over 36 months. Cox regression was used to test for associations between lagged predictors and hazard of transition to heroin use. Potential predictors were based on those suggested in the literature. We also computed population attributable risk (PAR) and the rate of heroin transition. Results Over 36 months, 27 (7.5%) participants initiated heroin use; all were white, and the rate of heroin initiation was 2.8% per year (95% CI=1.9%–4.1%). Mean length of PO at first reported heroin use was 6.2 years (SD=1.9). Lifetime PO dependence (AHR=2.39, 95% CI= 1.07–5.48; PAR=32%, 95% CI=−2%–64%), early age of PO initiation (AHR=3.08, 95%; CI= 1.26–7.47; PAR=30%, 95% CI=2%–59%), using illicit POs to get high but not to self-medicate a health problem (AHR=4.83, 95% CI= 2.11–11.0; PAR=38%, 95% CI=12%–65%), and ever using PO non-orally most often (AHR=6.57, 95% CI=2.81–17.2; PAR=63%, 95% CI=31%–86%) were significant predictors. Conclusion This is one of the first prospective studies to test observations from previous cross-sectional and retrospective research on the relationship between illicit PO use and heroin initiation among young, initially non-opioid dependent PO users. The results provide insights into targets for the design of urgently needed prevention interventions. PMID:26785634

Analysis of clinical features and visual outcomes of pars planitis.

PubMed

Berker, Nilufer; Sen, Emine; Elgin, Ufuk; Atilgan, Cemile Ucgul; Dursun, Erdem; Yilmazbas, Pelin

2018-04-01

To evaluate the demographic characteristics, clinical features, treatment and outcomes of patients with pars planitis in a tertiary referral center in Turkey. Medical records of patients with pars planitis were retrospectively reviewed. The data including demographic and ocular features and treatment outcomes were recorded. The distribution of clinical findings and complications were evaluated according to age and gender groups. The changes in final BCVA compared to the initial BCVA were noted. Statistical analysis was performed using SPSS software (Version 18.0, SPSS Inc., Chicago, USA). Twenty-seven patients (54 eyes) were included in this study. 16 patients were male (59.3%), and 11 were female (40.7%). Mean age at diagnosis was 12.84 ± 8.26 (range 4-36) years. Mean follow-up period was 61.3 ± 52.15 (range 9-172) months. Mean BCVA was 0.58 ± 0.36 (range 0.03-1.00) (0.40 ± 0.45 logMAR) at presentation, and 0.81 ± 0.28 (range 0.10-1.00) (0.14 ± 0.27 logMAR) at final visit (P = 0.001). Vitreous inflammation (100%), vitreous haze (92.6%), snowballs (74.1%), snowbanks (66.7%), anterior chamber cells (66.7%) and peripheral retinal vascular sheathing (48.1%) were the most common presentations. Ocular complications included vitreous condensation (51.9%), cystoid macular edema (22.2%), cataract (18.5%), inferior peripheral retinal detachment (11.1%), glaucoma (5.6%) and vitreous hemorrhage (3.7%). Treatments included topical, periocular, intravitreal and systemic corticosteroids, immunosuppressives, peripheral laser photocoagulation and pars plana vitrectomy when needed. Pars planitis is an idiopathic chronic intermediate uveitis mostly affecting children and adolescents. In spite of its chronic nature with high potential of causing ocular complications, adequate treatment and close follow-up lead to favorable visual outcomes.

The nursing hypothesis: an evolutionary account of emotional modulation of the postauricular reflex.

PubMed

Johnson, Gabriella M; Valle-Inclán, Fernando; Geary, David C; Hackley, Steven A

2012-02-01

The postauricular reflex (PAR) is anomalous because it seems to be potentiated during positive emotions and inhibited during negative states, unlike eyeblink and other components of the startle reflex. Two evolutionary explanations based on simian facial emotion expressions were tested. Reflexes were elicited while 47 young adult volunteers made lip pursing or grimacing poses and viewed neutral, intimidating, or appetitive photos. The PAR was enhanced during appetitive slides, but only as subjects carried out the lip-pursing maneuver. These results support the nursing hypothesis, which assumes that infant mammals instinctively retract their pinnae while nursing in order to comfortably position the head. Appetitive emotions prime the ear-retraction musculature, even in higher primates whose postauricular muscles are vestigial. Copyright © 2011 Society for Psychophysiological Research.

Precursor ion scanning-mass spectrometry for the determination of nitro functional groups in atmospheric particulate organic matter.

PubMed

Dron, Julien; Abidi, Ehgere; Haddad, Imad El; Marchand, Nicolas; Wortham, Henri

2008-06-23

An analytical method for the quantitative determination of the total nitro functional group (R-NO2) content in atmospheric particulate organic matter is developed. The method is based on the selectivity of NO2(-) (m/z 46) precursor ion scanning (PAR 46) by atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS). PAR 46 was experimented on 16 nitro compounds of different molecular structures and was compared with a neutral loss of NO (30 amu) technique in terms of sensitivity and efficiency to characterize the nitro functional groups. Covering a wider range of compounds, PAR 46 was preferred and applied to reference mixtures containing all the 16 compounds under study. Repeatability carried out using an original statistical approach, and calibration experiments were performed on the reference mixtures proven the suitability of the technique for quantitative measurements of nitro functional groups in samples of environmental interest with good accuracy. A linear range was obtained for concentrations ranging between 0.005 and 0.25 mM with a detection limit of 0.001 mM of nitro functional groups. Finally, the analytical error based on an original statistical approach applied to numerous reference mixtures was below 20%. Despite of potential artifacts related to nitro-alkanes and organonitrates, this new methodology offers a promising alternative to FT-IR measurements. The relevance of the method and its potentialities are demonstrated through its application to aerosols collected in the EUPHORE simulation chamber during o-xylene photooxidation experiments and in a suburban area of a French alpine valley during summer.

Tricyclic GyrB/ParE (TriBE) Inhibitors: A New Class of Broad-Spectrum Dual-Targeting Antibacterial Agents

PubMed Central

Tari, Leslie W.; Li, Xiaoming; Trzoss, Michael; Bensen, Daniel C.; Chen, Zhiyong; Lam, Thanh; Zhang, Junhu; Lee, Suk Joong; Hough, Grayson; Phillipson, Doug; Akers-Rodriguez, Suzanne; Cunningham, Mark L.; Kwan, Bryan P.; Nelson, Kirk J.; Castellano, Amanda; Locke, Jeff B.; Brown-Driver, Vickie; Murphy, Timothy M.; Ong, Voon S.; Pillar, Chris M.; Shinabarger, Dean L.; Nix, Jay; Lightstone, Felice C.; Wong, Sergio E.; Nguyen, Toan B.; Shaw, Karen J.; Finn, John

2013-01-01

Increasing resistance to every major class of antibiotics and a dearth of novel classes of antibacterial agents in development pipelines has created a dwindling reservoir of treatment options for serious bacterial infections. The bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV, are validated antibacterial drug targets with multiple prospective drug binding sites, including the catalytic site targeted by the fluoroquinolone antibiotics. However, growing resistance to fluoroquinolones, frequently mediated by mutations in the drug-binding site, is increasingly limiting the utility of this antibiotic class, prompting the search for other inhibitor classes that target different sites on the topoisomerase complexes. The highly conserved ATP-binding subunits of DNA gyrase (GyrB) and topoisomerase IV (ParE) have long been recognized as excellent candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, to date, no natural product or small molecule inhibitors targeting these sites have succeeded in the clinic, and no inhibitors of these enzymes have yet been reported with broad-spectrum antibacterial activity encompassing the majority of Gram-negative pathogens. Using structure-based drug design (SBDD), we have created a novel dual-targeting pyrimidoindole inhibitor series with exquisite potency against GyrB and ParE enzymes from a broad range of clinically important pathogens. Inhibitors from this series demonstrate potent, broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens of clinical importance, including fluoroquinolone resistant and multidrug resistant strains. Lead compounds have been discovered with clinical potential; they are well tolerated in animals, and efficacious in Gram-negative infection models. PMID:24386374

Estimating Photosynthetically Available Radiation (PAR) at the Earth's surface from satellite observations

NASA Technical Reports Server (NTRS)

Frouin, Robert

1993-01-01

Current satellite algorithms to estimate photosynthetically available radiation (PAR) at the earth' s surface are reviewed. PAR is deduced either from an insolation estimate or obtained directly from top-of-atmosphere solar radiances. The characteristics of both approaches are contrasted and typical results are presented. The inaccuracies reported, about 10 percent and 6 percent on daily and monthly time scales, respectively, are useful to model oceanic and terrestrial primary productivity. At those time scales variability due to clouds in the ratio of PAR and insolation is reduced, making it possible to deduce PAR directly from insolation climatologies (satellite or other) that are currently available or being produced. Improvements, however, are needed in conditions of broken cloudiness and over ice/snow. If not addressed properly, calibration/validation issues may prevent quantitative use of the PAR estimates in studies of climatic change. The prospects are good for an accurate, long-term climatology of PAR over the globe.

The polarity protein partitioning-defective 1 (PAR-1) regulates dendritic spine morphogenesis through phosphorylating postsynaptic density protein 95 (PSD-95).

PubMed

Wu, Qian; DiBona, Victoria L; Bernard, Laura P; Zhang, Huaye

2012-08-31

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95.

Is There an "F" in Your PAR? Understanding, Teaching and Doing Action Research

ERIC Educational Resources Information Center

Lorenzetti, Liza; Walsh, Christine Ann

2014-01-01

Participatory Action Research (PAR) is increasingly recognized within academic research and pedagogy. What are the benefits of including feminism within participatory action research and teaching? In responding to this question, we discuss the similarities and salient differences between PAR and feminist informed PAR (FPAR). There are eight themes…

PAR-2 receptor-induced effects on human eccrine sweat gland cells.

PubMed

L Bovell, Douglas; Kofler, Barbara; Lang, Roland

2009-01-01

Serine proteases can induce cell signaling by stimulating G-protein-coupled receptors, called proteinase-activated receptors (PAR's) on a variety of epithelial cells. While PAR-2, one such receptor, activates cell signaling in a secretory cell line derived from human sweat glands, there was no information on their presence and effects on intact sweat glands. PAR-2 presence and activation of eccrine sweat glands isolated from human skin samples was investigated using Western blot analysis, immunohistochemistry, electron microscopy (EM) and Ca(2+) imaging. Anti-human PAR-2 antibody demonstrated the presence of these receptors in eccrine sweat glands. EM showed that PAR-2 activation resulted in degranulation of secretory cells. Ca(2+) imaging using PAR-2 activators demonstrated a two phase increase in [Ca(2+)](i) which was dependent on extracellular Ca(2+) for the second phase, and that the response could be blocked by prior incubation with xestospongin, the IP(3) receptor blocker. The results demonstrated that PAR-2 receptors are present in human sweat gland secretory cells and that these receptors are functionally active and can induce changes associated with secretory events in eccrine glands.

Protease Activated Receptor-2 Contributes to Heart Failure

PubMed Central

Antoniak, Silvio; Sparkenbaugh, Erica M.; Tencati, Michael; Rojas, Mauricio; Mackman, Nigel; Pawlinski, Rafal

2013-01-01

Heart failure is a major clinical problem worldwide. Previous studies have demonstrated an important role for G protein-coupled receptors, including protease-activated receptors (PARs), in the pathology of heart hypertrophy and failure. Activation of PAR-2 on cardiomyocytes has been shown to induce hypertrophic growth in vitro. PAR-2 also contributes to myocardial infarction and heart remodeling after ischemia/reperfusion injury. In this study, we found that PAR-2 induced hypertrophic growth of cultured rat neonatal cardiomyocytes in a MEK1/2 and p38 dependent manner. In addition, PAR-2 activation on mouse cardiomyocytes increased expression of the pro-fibrotic chemokine MCP-1. Furthermore, cardiomyocyte-specific overexpression of PAR-2 in mice induced heart hypertrophy, cardiac fibrosis, inflammation and heart failure. Finally, in a mouse model of myocardial infarction induced by permanent ligation of the left anterior descending coronary artery, PAR-2 deficiency attenuated heart remodeling and improved heart function independently of its contribution to the size of the initial infarct. Taken together, our data indicate that PAR-2 signaling contributes to the pathogenesis of hypertrophy and heart failure. PMID:24312345

The protease-activated receptor-2 upregulates keratinocyte phagocytosis.

PubMed

Sharlow, E R; Paine, C S; Babiarz, L; Eisinger, M; Shapiro, S; Seiberg, M

2000-09-01

The protease-activated receptor-2 (PAR-2) belongs to the family of seven transmembrane domain receptors, which are activated by the specific enzymatic cleavage of their extracellular amino termini. Synthetic peptides corresponding to the tethered ligand domain (SLIGRL in mouse, SLIGKV in human) can activate PAR-2 without the need for receptor cleavage. PAR-2 activation is involved in cell growth, differentiation and inflammatory processes, and was shown to affect melanin and melanosome ingestion by human keratinocytes. Data presented here suggest that PAR-2 activation may regulate human keratinocyte phagocytosis. PAR-2 activation by trypsin, SLIGRL or SLIGKV increased the ability of keratinocytes to ingest fluorescently labeled microspheres or E. coli K-12 bioparticles. This PAR-2 mediated increase in keratinocyte phagocytic capability correlated with an increase in actin polymerization and *-actinin reorganization, cell surface morphological changes and increased soluble protease activity. Moreover, addition of serine protease inhibitors downmodulated both the constitutive and the PAR-2 mediated increases in phagocytosis, suggesting that serine proteases mediate this functional activity in keratinocytes. PAR-2 involvement in keratinocyte phagocytosis is a novel function for this receptor.

Protease-Activated Receptor-2 Deficiency Attenuates Atherosclerotic Lesion Progression and Instability in Apolipoprotein E-Deficient Mice

PubMed Central

Zuo, Pengfei; Zuo, Zhi; Zheng, Yueyue; Wang, Xin; Zhou, Qianxing; Chen, Long; Ma, Genshan

2017-01-01

Inflammatory mechanisms are involved in the process of atherosclerotic plaque formation and rupture. Accumulating evidence suggests that protease-activated receptor (PAR)-2 contributes to the pathophysiology of chronic inflammation on the vasculature. To directly examine the role of PAR-2 in atherosclerosis, we generated apolipoprotein E/PAR-2 double-deficient mice. Mice were fed with high-fat diet for 12 weeks starting at ages of 6 weeks. PAR-2 deficiency attenuated atherosclerotic lesion progression with reduced total lesion area, reduced percentage of stenosis and reduced total necrotic core area. PAR-2 deficiency increased fibrous cap thickness and collagen content of plaque. Moreover, PAR-2 deficiency decreased smooth muscle cell content, macrophage accumulation, matrix metallopeptidase-9 expression and neovascularization in plaque. Relative quantitative PCR assay using thoracic aorta revealed that PAR-2 deficiency reduced mRNA expression of inflammatory molecules, such as vascular cell adhesion molecule-1, intercellular adhesion molecule-1, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1. In vitro experiment, we found that PAR-2 deficiency reduced mRNA expression of interferon-γ, interleukin-6, TNF-α and MCP-1 in macrophage under unstimulated and lipopolysaccharide-stimulated conditions. These results suggest that PAR-2 deficiency attenuates the progression and instability of atherosclerotic plaque. PMID:28959204

The expression and activation of protease-activated receptor-2 correlate with skin color.

PubMed

Babiarz-Magee, Laura; Chen, Nannan; Seiberg, Miri; Lin, Connie B

2004-06-01

Skin color results from the production and distribution of melanin in the epidermis. The protease-activated receptor-2 (PAR-2), expressed on keratinocytes but not on melanocytes, is involved in melanosome uptake via phagocytosis, and modulation of PAR-2 activation affects skin color. The pattern of melanosome distribution within the epidermis is skin color-dependent. In vitro, this distribution pattern is regulated by the ethnic origin of the keratinocytes, not the melanocytes. Therefore, we hypothesized that PAR-2 may play a role in the modulation of pigmentation in a skin type-dependent manner. We examined the expression of PAR-2 and its activator, trypsin, in human skins with different pigmentary levels. Here we show that PAR-2 and trypsin are expressed in higher levels, and are differentially localized in highly pigmented, relative to lightly pigmented skins. Moreover, highly pigmented skins exhibit an increase in PAR-2-specific protease cleavage ability. Microsphere phagocytosis was more efficient in keratinocytes from highly pigmented skins, and PAR-2 induced phagocytosis resulted in more efficient microsphere ingestion and more compacted microsphere organization in dark skin-derived keratinocytes. These results demonstrate that PAR-2 expression and activity correlate with skin color, suggesting the involvement of PAR-2 in ethnic skin color phenotypes.

Cytoprotective signaling by activated protein C requires protease-activated receptor-3 in podocytes

PubMed Central

Madhusudhan, Thati; Wang, Hongjie; Straub, Beate K.; Gröne, Elisabeth; Zhou, Qianxing; Shahzad, Khurrum; Müller-Krebs, Sandra; Schwenger, Vedat; Gerlitz, Bruce; Grinnell, Brian W.; Griffin, John H.; Reiser, Jochen; Gröne, Hermann-Josef; Esmon, Charles T.; Nawroth, Peter P.

2012-01-01

The cytoprotective effects of activated protein C (aPC) are well established. In contrast, the receptors and signaling mechanism through which aPC conveys cytoprotection in various cell types remain incompletely defined. Thus, within the renal glomeruli, aPC preserves endothelial cells via a protease-activated receptor-1 (PAR-1) and endothelial protein C receptor-dependent mechanism. Conversely, the signaling mechanism through which aPC protects podocytes remains unknown. While exploring the latter, we identified a novel aPC/PAR-dependent cytoprotective signaling mechanism. In podocytes, aPC inhibits apoptosis through proteolytic activation of PAR-3 independent of endothelial protein C receptor. PAR-3 is not signaling competent itself as it requires aPCinduced heterodimerization with PAR-2 (human podocytes) or PAR-1 (mouse podocytes). This cytoprotective signaling mechanism depends on caveolin-1 dephosphorylation. In vivo aPC protects against lipopolysaccharide-induced podocyte injury and proteinuria. Genetic deletion of PAR-3 impairs the nephroprotective effect of aPC, demonstrating the crucial role of PAR-3 for aPC-dependent podocyte protection. This novel, aPC-mediated interaction of PARs demonstrates the plasticity and cell-specificity of cytoprotective aPC signaling. The evidence of specific, dynamic signaling complexes underlying aPC-mediated cytoprotection may allow the design of cell type specific targeted therapies. PMID:22117049

Par Pond vegetation status Summer 1995 -- Summary

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

Mackey, H.E. Jr.; Riley, R.S.

1996-01-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar tomore » the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned.« less

Flow cytometry analysis reveals different activation profiles of thrombin- or TRAP-stimulated platelets in db/db mice. The regulatory role of PAR-3.

PubMed

Kassassir, Hassan; Siewiera, Karolina; Talar, Marcin; Przygodzki, Tomasz; Watala, Cezary

2017-06-01

Recent studies have shown that it may be the concentration of thrombin, which is discriminative in determining of the mechanism of platelet activation via protease activated receptors (PARs). Whether the observed phenomenon of differentiated responses of mouse platelets to various thrombin concentrations in non-diabetic db/+ and diabetic db/db mice depends upon the concerted action of various PARs, remains to be established. We found elevated reactivity of platelets, as well as the enhanced PAR-3 expression in response to both the used concentrations of AYPGKF in db/db mice, as compared to db/+ heterozygotes. At low concentration of thrombin platelets from diabetic mice demonstrated hyperreactivity, reflected by higher expression of PAR-3. For higher thrombin concentration, blood platelets from db/db mice appeared hyporeactive, compared to db/+ animals, while no significant differences in PAR-3 expression were observed between diabetic and non-diabetic mice. The novel and previously unreported finding resulting from our study is that the increased expression of PAR-3 in response to either TRAP for PAR-4 or low thrombin (when PAR-4 is not the efficient thrombin receptor) may be one of the key events contributing to higher reactivity of platelets in db/db mice. Copyright © 2017 Elsevier Inc. All rights reserved.

Binding of high molecular weight kininogen to human endothelial cells is mediated via a site within domains 2 and 3 of the urokinase receptor.

PubMed Central

Colman, R W; Pixley, R A; Najamunnisa, S; Yan, W; Wang, J; Mazar, A; McCrae, K R

1997-01-01

The urokinase receptor (uPAR) binds urokinase-type plasminogen activator (u-PA) through specific interactions with uPAR domain 1, and vitronectin through interactions with a site within uPAR domains 2 and 3. These interactions promote the expression of cell surface plasminogen activator activity and cellular adhesion to vitronectin, respectively. High molecular weight kininogen (HK) also stimulates the expression of cell surface plasminogen activator activity through its ability to serve as an acquired receptor for prekallikrein, which, after its activation, may directly activate prourokinase. Here, we report that binding of the cleaved form of HK (HKa) to human umbilical vein endothelial cells (HUVEC) is mediated through zinc-dependent interactions with uPAR. These occur through a site within uPAR domains 2 and 3, since the binding of 125I-HKa to HUVEC is inhibited by vitronectin, anti-uPAR domain 2 and 3 antibodies and soluble, recombinant uPAR (suPAR), but not by antibody 7E3, which recognizes the beta chain of the endothelial cell vitronectin receptor (integrin alphavbeta3), or fibrinogen, another alphavbeta3 ligand. We also demonstrate the formation of a zinc-dependent complex between suPAR and HKa. Interactions of HKa with endothelial cell uPAR may underlie its ability to promote kallikrein-dependent cell surface plasmin generation, and also explain, in part, its antiadhesive properties. PMID:9294114

Aspergillus fumigatus Increased PAR-2 Expression and Elevated Proinflammatory Cytokines Expression Through the Pathway of PAR-2/ERK1/2 in Cornea.

PubMed

Niu, Yawen; Zhao, Guiqiu; Li, Cui; Lin, Jing; Jiang, Nan; Che, Chengye; Zhang, Jie; Xu, Qiang

2018-01-01

To determine the role of protease-activated receptor-2 (PAR-2) in cornea infected by Aspergillus fumigatus. PAR-2 was tested in normal and infected corneas of C57BL/6 mice. Mice corneas were infected with A. fumigatus with or without pretreatment of PAR-2 antagonist (FSLLRY-NH2). Polymorphonuclear neutrophilic leukocytes (PMNs) were stimulated with 75% ethanol-killed A. fumigatus with or without pretreatment of FSLLRY-NH2. Disease severity was documented by clinical score and photographs with a slit lamp. PCR, Western blot, and ELISA tested expression of PAR-2, IL-1β, TNF-α, IFN-γ, MIP-2, and p-ERK1/2. PMN infiltration was assessed by myeloperoxidase assay and immunofluorescent staining. PAR-2 expression was significantly elevated by A. fumigatus, whereas the upregulation was significantly inhibited by FSLLRY-NH2 in mice corneas. FSLLRY-NH2 decreased disease response, PMN infiltration, and proinflammatory cytokine expression compared with infected control. In PMNs, PAR-2 expression was also significantly increased by A. fumigatus, which was significantly inhibited by FSLLRY-NH2. FSLLRY-NH2 significantly inhibited proinflammatory cytokine protein expression, as compared with that in infected control cells, which may be modified by p-ERK1/2. These data provide evidence that A. fumigatus increased PAR-2 expression and elevated disease, PMN infiltration, and proinflammatory cytokine expression through PAR-2, which may be modified by p-ERK1/2.

Pharmacological Targeting of Protease-Activated Receptor 2 Affords Protection from Bleomycin-Induced Pulmonary Fibrosis

PubMed Central

Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C Arnold

2015-01-01

Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease that remains refractory to therapy. Despite increasing evidence that protease-activated receptor 2 (PAR-2) contributes to fibrosis, its importance in pulmonary fibrosis is under debate. We addressed whether PAR-2 deficiency persistently reduces bleomycin-induced pulmonary fibrosis or merely delays disease progression and whether pharmacological PAR-2 inhibition limits experimental pulmonary fibrosis. Bleomycin was instilled intranasally into wild-type or PAR-2–deficient mice in the presence/absence of a specific PAR-2 antagonist (P2pal-18S). Pulmonary fibrosis was consistently reduced in PAR-2–deficient mice throughout the fibrotic phase, as evident from reduced Ashcroft scores (29%) and hydroxyproline levels (26%) at d 28. Moreover, P2pal-18S inhibited PAR-2–induced profibrotic responses in both murine and primary human pulmonary fibroblasts (p < 0.05). Once daily treatment with P2pal-18S reduced the severity and extent of fibrotic lesions in lungs of bleomycin-treated wild-type mice but did not further reduce fibrosis in PAR-2–deficient mice. Importantly, P2pal-18S treatment starting even 7 d after the onset of fibrosis limits pulmonary fibrosis as effectively as when treatment was started together with bleomycin instillation. Overall, PAR-2 contributes to the progression of pulmonary fibrosis, and targeting PAR-2 may be a promising therapeutic strategy for treating pulmonary fibrosis. PMID:26147947

Novel role of prostate apoptosis response-4 tumor suppressor in B-cell chronic lymphocytic leukemia.

PubMed

McKenna, Mary K; Noothi, Sunil K; Alhakeem, Sara S; Oben, Karine Z; Greene, Joseph T; Mani, Rajeswaran; Perry, Kathryn L; Collard, James P; Rivas, Jacqueline R; Hildebrandt, Gerhard; Fleischman, Roger; Durbin, Eric B; Byrd, John C; Wang, Chi; Muthusamy, Natarajan; Rangnekar, Vivek M; Bondada, Subbarao

2018-04-25

Prostate apoptosis response-4 (Par-4), a pro-apoptotic tumor suppressor protein, is down regulated in many cancers including renal cell carcinoma, glioblastoma, endometrial and breast cancer. Par-4 induces apoptosis selectively in various types of cancer cells but not normal cells. We found that chronic lymphocytic leukemia (CLL) cells from human patients and from the Eµ-Tcl1 mice constitutively express Par-4 in greater amounts than normal B-1 or B-2 cells. Interestingly, knockdown of Par-4 in human CLL derived Mec-1 cells results in a robust increase in p21/WAF1 expression and decreased growth due to delayed G1 to S cell cycle transition. Lack of Par-4 also increased the expression of p21 and delayed CLL growth in Eμ-Tcl1 mice. Par-4 expression in CLL cells required constitutively active B-cell receptor (BCR) signaling, as inhibition of BCR signaling with FDA approved drugs caused a decrease in Par-4 mRNA and protein, and an increase in apoptosis. In particular, activities of Lyn, a Src family kinase, spleen tyrosine kinase and Bruton's tyrosine kinase are required for Par-4 expression in CLL cells, suggesting a novel regulation of Par-4 through BCR signaling. Together, these results suggest that Par-4 may play a novel pro-growth rather than pro-apoptotic role in CLL and could be targeted to enhance the therapeutic effects of BCR signaling inhibitors. Copyright © 2018 American Society of Hematology.

Poly(ADP-ribose) polymerase-dependent energy depletion occurs through inhibition of glycolysis.

PubMed

Andrabi, Shaida A; Umanah, George K E; Chang, Calvin; Stevens, Daniel A; Karuppagounder, Senthilkumar S; Gagné, Jean-Philippe; Poirier, Guy G; Dawson, Valina L; Dawson, Ted M

2014-07-15

Excessive poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) activation kills cells via a cell-death process designated "parthanatos" in which PAR induces the mitochondrial release and nuclear translocation of apoptosis-inducing factor to initiate chromatinolysis and cell death. Accompanying the formation of PAR are the reduction of cellular NAD(+) and energetic collapse, which have been thought to be caused by the consumption of cellular NAD(+) by PARP-1. Here we show that the bioenergetic collapse following PARP-1 activation is not dependent on NAD(+) depletion. Instead PARP-1 activation initiates glycolytic defects via PAR-dependent inhibition of hexokinase, which precedes the NAD(+) depletion in N-methyl-N-nitroso-N-nitroguanidine (MNNG)-treated cortical neurons. Mitochondrial defects are observed shortly after PARP-1 activation and are mediated largely through defective glycolysis, because supplementation of the mitochondrial substrates pyruvate and glutamine reverse the PARP-1-mediated mitochondrial dysfunction. Depleting neurons of NAD(+) with FK866, a highly specific noncompetitive inhibitor of nicotinamide phosphoribosyltransferase, does not alter glycolysis or mitochondrial function. Hexokinase, the first regulatory enzyme to initiate glycolysis by converting glucose to glucose-6-phosphate, contains a strong PAR-binding motif. PAR binds to hexokinase and inhibits hexokinase activity in MNNG-treated cortical neurons. Preventing PAR formation with PAR glycohydrolase prevents the PAR-dependent inhibition of hexokinase. These results indicate that bioenergetic collapse induced by overactivation of PARP-1 is caused by PAR-dependent inhibition of glycolysis through inhibition of hexokinase.

IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS

EPA Science Inventory

ABSTRACT
The use of flame retardant chemicals in furniture fabric could pose a potential health risk to consumers from dermal absorption of these compounds. The objective of this study was to examine the in vitro dermal absorption of two flame retardant chemicals, [14C]-d...

Low and moderate photosynthetically active radiation affects the flavonol glycosides and hydroxycinnamic acid derivatives in kale (Brassica oleracea var. sabellica) dependent on two low temperatures.

PubMed

Neugart, Susanne; Fiol, Michaela; Schreiner, Monika; Rohn, Sascha; Zrenner, Rita; Kroh, Lothar W; Krumbein, Angelika

2013-11-01

Kale (Brassica oleracea var. sabellica) contains a large number of naturally occurring structurally different non-acylated and acylated flavonol glycosides as well as hydroxycinnamic acid derivatives. The objective of this study was to determine the effect of low and moderate photosynthetic active radiation (PAR) and how these levels interact with low temperature in these phenolic compounds. Juvenile kale plants were treated with PAR levels from 200 to 800 μmol m(-2) s(-1) at 5 and 10 °C under defined conditions in climate chambers. Of the investigated 20 compounds, 11 and 17 compounds were influenced by PAR and temperature, respectively. In addition, an interaction between PAR and temperature was found for eight compounds. The response of the phenolic compounds to PAR was structure-dependent. While quercetin triglycosides increased with higher PAR at 5 and 10 °C, the kaempferol triglycosides exhibited the highest concentrations at 400 μmol m(-2) s(-1). In contrast, kaempferol diglycosides exhibited the highest concentrations at increased PAR levels of 600 and 800 μmol m(-2) s(-1) at 10 °C. However, key genes of flavonol biosynthesis were influenced by temperature but remained unaffected by PAR. Furthermore, there was no interaction between the PAR level and the low temperature in the response of hydroxycinnamic acid derivatives in kale with the exception of caffeoylquinic acid, which decreased with higher PAR levels of 600 and 800 μmol m(-2) s(-1) and at a lower temperature. In conclusion, PAR and its interaction with temperature could be a suitable tool for modifying the profile of phenolic compounds. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Urokinase receptor and CXCR4 are regulated by common microRNAs in leukaemia cells

PubMed Central

Alfano, Daniela; Gorrasi, Anna; Li Santi, Anna; Ricci, Patrizia; Montuori, Nunzia; Selleri, Carmine; Ragno, Pia

2015-01-01

The urokinase-type plasminogen activator (uPA) receptor (uPAR) focuses uPA proteolytic activity on the cell membrane, promoting localized degradation of extracellular matrix (ECM), and binds vitronectin (VN), mediating cell adhesion to the ECM. uPAR-bound uPA and VN induce proteolysis-independent intracellular signalling, regulating cell adhesion, migration, survival and proliferation. uPAR cross-talks with CXCR4, the receptor for the stroma-derived factor 1 chemokine. CXCR4 is crucial in the trafficking of hematopoietic stem cells from/to the bone marrow, which involves also uPAR. Both uPAR and CXCR4 are expressed in acute myeloid leukaemia (AML), with a lower expression in undifferentiated and myeloid subsets, and higher expression in myelomonocytic and promyelocytic subsets. We hypothesized a microRNA (miR)-mediated co-regulation of uPAR and CXCR4 expression, which could allow their cross-talk at the cell surface. We identified three miRs, miR-146a, miR-335 and miR-622, regulating the expression of both uPAR and CXCR4 in AML cell lines. Indeed, these miRs directly target the 3′untranslated region of both uPAR- and CXCR4-mRNAs; accordingly, uPAR/CXCR4 expression is reduced by their overexpression in AML cells and increased by their specific inhibitors. Overexpression of all three miRs impairs migration, invasion and proliferation of myelomonocytic cells. Interestingly, we observed an inverse relationship between uPAR/CXCR4 expression and miR-146a and miR-335 levels in AML blasts, suggesting their possible role in the regulation of uPAR/CXCR4 expression also in vivo. PMID:26082201

Activated PAR-2 regulates pancreatic cancer progression through ILK/HIF-α-induced TGF-α expression and MEK/VEGF-A-mediated angiogenesis.

PubMed

Chang, Li-Hsun; Pan, Shiow-Lin; Lai, Chin-Yu; Tsai, An-Chi; Teng, Che-Ming

2013-08-01

Tissue factor initiates the process of thrombosis and activates cell signaling through protease-activated receptor-2 (PAR-2). The aim of this study was to investigate the pathological role of PAR-2 signaling in pancreatic cancer. We first demonstrated that activated PAR-2 up-regulated the protein expression of both hypoxia-inducible factor-1α (HIF-1α) and HIF-2α, resulting in enhanced transcription of transforming growth factor-α (TGF-α). Down-regulation of HIFs-α by siRNA or YC-1, an HIF inhibitor, resulted in depleted levels of TGF-α protein. Furthermore, PAR-2, through integrin-linked kinase (ILK) signaling, including the p-AKT, promoted HIF protein expression. Diminishing ILK by siRNA decreased the levels of PAR-2-induced p-AKT, HIFs-α, and TGF-α; our results suggest that ILK is involved in the PAR-2-mediated TGF-α via an HIF-α-dependent pathway. Furthermore, the culture medium from PAR-2-treated pancreatic cancer cells enhanced human umbilical vein endothelial cell proliferation and tube formation, which was blocked by the MEK inhibitor, PD98059. We also found that activated PAR-2 enhanced tumor angiogenesis through the release of vascular endothelial growth factor-A (VEGF-A) from cancer cells, independent of the ILK/HIFs-α pathways. Consistent with microarray analysis, activated PAR-2 induced TGF-A and VEGF-A gene expression. In conclusion, the activation of PAR-2 signaling induced human pancreatic cancer progression through the induction of TGF-α expression by ILK/HIFs-α, as well as through MEK/VEGF-A-mediated angiogenesis, and it plays a role in the interaction between cancer progression and cancer-related thrombosis. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Effects of three types of oil dispersants on biodegradation of dispersed crude oil in water surrounding two Persian gulf provinces.

PubMed

Zolfaghari-Baghbaderani, Azadeh; Emtyazjoo, Mozhgan; Poursafa, Parinaz; Mehrabian, Sedigheh; Bijani, Samira; Farkhani, Daryoush; Mirmoghtadaee, Parisa

2012-01-01

To determine the most effective and biodegradable dispersant of spilled oil in water surrounding two Persian Gulf provinces. This study compared the effects of three dispersants, Pars 1, Pars 2, and Gamlen OD4000 on removal of oil in two Persian Gulf provinces' water. Overall, 16 stations were selected. Using the Well method, the growth rate of isolated bacteria and fungi was identified. To specify the growth rate of microorganisms and their usage of oil in the presence of the above-mentioned dispersants, as exclusive sources of carbon, the bacteria were grown in culture medium for 28 days at 120 rpm, 30°C, and their optical density was measured by spectrophotometry. Then, we tested biological oxygen demand (BOD) and chemical oxygen demand (COD) in microorganisms. The highest growth rate was documented for the growth of microorganisms on either Pars 1 or Pars 2 dispersants or their mixtures with oil. However, the culture having microorganisms grown on Pars 1 had higher BOD and COD than the other two dispersants (9200 and 16800 versus 500 and 960, P < 0.05). Mixture of oil and Pars 2 as well as oil and Pars 1 dispersants showed the highest BODs and CODs, respectively. In the Bahregan province, microorganisms grown on Pars 2 had maximum amount of BOD and COD in comparison with Pars 1 and Gamlen dispersants (7100 and 15200 versus 6000 and 10560, P < 0.05). Pars 1 and Pars 2 were the most effective dispersants with highest degradability comparing Gamlen. In each region, the most suitable compound for removing oil spill from offshores with least secondary contamination should be investigated.

Protease-Activated Receptor 4 Induces Bladder Pain through High Mobility Group Box-1

PubMed Central

Kouzoukas, Dimitrios E.; Ma, Fei; Meyer-Siegler, Katherine L.; Westlund, Karin N.; Hunt, David E.; Vera, Pedro L.

2016-01-01

Pain is the significant presenting symptom in Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS). Activation of urothelial protease activated receptor 4 (PAR4) causes pain through release of urothelial macrophage migration inhibitory factor (MIF). High Mobility Group Box-1 (HMGB1), a chromatin-binding protein, mediates bladder pain (but not inflammation) in an experimental model (cyclophosphamide) of cystitis. To determine if PAR4-induced bladder hypersensitivity depends on HMGB1 downstream, we tested whether: 1) bladder PAR4 stimulation affected urothelial HMGB1 release; 2) blocking MIF inhibited urothelial HMGB1 release; and 3) blocking HMGB1 prevented PAR4-induced bladder hypersensitivity. HMGB1 release was examined in immortalized human urothelial cultures (UROtsa) exposed to PAR4-activating peptide (PAR4-AP; 100 μM; 2 hours) or scrambled control peptide. Female C57BL/6 mice, pretreated with a HMGB1 inhibitor (glycyrrhizin: 50 mg/kg; ip) or vehicle, received intravesical PAR4-AP or a control peptide (100 μM; 1 hour) to determine 1) HMGB1 levels at 1 hour in the intravesical fluid (released HMGB1) and urothelium, and 2) abdominal hypersensitivity to von Frey filament stimulation 24 hours later. We also tested mice pretreated with a MIF blocker (ISO-1: 20 mg/kg; ip) to determine whether MIF mediated PAR4-induced urothelial HMGB1 release. PAR4-AP triggered HMGB1 release from human (in vitro) and mice (in vivo) urothelial cells. Intravesical PAR4 activation elicited abdominal hypersensitivity in mice that was prevented by blocking HMGB1. MIF inhibition prevented PAR4-mediated HMGB1 release from mouse urothelium. Urothelial MIF and HGMB1 represent novel targets for therapeutic intervention in bladder pain conditions. PMID:27010488

Population attributable risks of patient, child and organizational risk factors for perinatal mortality in hospital births.

PubMed

Poeran, Jashvant; Borsboom, Gerard J J M; de Graaf, Johanna P; Birnie, Erwin; Steegers, Eric A P; Bonsel, Gouke J

2015-04-01

The main objective of this study was to estimate the contributing role of maternal, child, and organizational risk factors in perinatal mortality by calculating their population attributable risks (PAR). The primary dataset comprised 1,020,749 singleton hospital births from ≥22 weeks' gestation (The Netherlands Perinatal Registry 2000-2008). PARs for single and grouped risk factors were estimated in four stages: (1) creating a duplicate dataset for each PAR analysis in which risk factors of interest were set to the most favorable value (e.g., all women assigned 'Western' for PAR calculation of ethnicity); (2) in the primary dataset an elaborate multilevel logistic regression model was fitted from which (3) the obtained coefficients were used to predict perinatal mortality in each duplicate dataset; (4) PARs were then estimated as the proportional change of predicted- compared to observed perinatal mortality. Additionally, PARs for grouped risk factors were estimated by using sequential values in two orders: after PAR estimation of grouped maternal risk factors, the resulting PARs for grouped child, and grouped organizational factors were estimated, and vice versa. The combined PAR of maternal, child and organizational factors is 94.4 %, i.e., when all factors are set to the most favorable value perinatal mortality is expected to be reduced with 94.4 %. Depending on the order of analysis, the PAR of maternal risk factors varies from 1.4 to 13.1 %, and for child- and organizational factors 58.7-74.0 and 7.3-34.3 %, respectively. In conclusion, the PAR of maternal-, child- and organizational factors combined is 94.4 %. Optimization of organizational factors may achieve a 34.3 % decrease in perinatal mortality.

Age- and gender-specific population attributable risks of metabolic disorders on all-cause and cardiovascular mortality in Taiwan

PubMed Central

2012-01-01

Background The extent of attributable risks of metabolic syndrome (MetS) and its components on mortality remains unclear, especially with respect to age and gender. We aimed to assess the age- and gender-specific population attributable risks (PARs) for cardiovascular disease (CVD)-related mortality and all-cause mortality for public health planning. Methods A total of 2,092 men and 2,197 women 30 years of age and older, who were included in the 2002 Taiwan Survey of Hypertension, Hyperglycemia, and Hyperlipidemia (TwSHHH), were linked to national death certificates acquired through December 31, 2009. Cox proportional hazard models were used to calculate adjusted hazard ratios and PARs for mortality, with a median follow-up of 7.7 years. Results The respective PAR percentages of MetS for all-cause and CVD-related mortality were 11.6 and 39.2 in men, respectively, and 18.6 and 44.4 in women, respectively. Central obesity had the highest PAR for CVD mortality in women (57.5%), whereas arterial hypertension had the highest PAR in men (57.5%). For all-cause mortality, younger men and post-menopausal women had higher PARs related to Mets and its components; for CVD mortality, post-menopausal women had higher overall PARs than their pre-menopausal counterparts. Conclusions MetS has a limited application to the PAR for all-cause mortality, especially in men; its PAR for CVD mortality is more evident. For CVD mortality, MetS components have higher PARs than MetS itself, especially hypertension in men and waist circumference in post-menopausal women. In addition, PARs for diabetes mellitus and low HDL-cholesterol may exceed 20%. We suggest differential control of risk factors in different subpopulation as a strategy to prevent CVD-related mortality. PMID:22321049

Effects of Three Types of Oil Dispersants on Biodegradation of Dispersed Crude Oil in Water Surrounding Two Persian Gulf Provinces

PubMed Central

Zolfaghari-Baghbaderani, Azadeh; Emtyazjoo, Mozhgan; Poursafa, Parinaz; Mehrabian, Sedigheh; Bijani, Samira; Farkhani, Daryoush; Mirmoghtadaee, Parisa

2012-01-01

Objective. To determine the most effective and biodegradable dispersant of spilled oil in water surrounding two Persian Gulf provinces. Methods. This study compared the effects of three dispersants, Pars 1, Pars 2, and Gamlen OD4000 on removal of oil in two Persian Gulf provinces' water. Overall, 16 stations were selected. Using the Well method, the growth rate of isolated bacteria and fungi was identified. To specify the growth rate of microorganisms and their usage of oil in the presence of the above-mentioned dispersants, as exclusive sources of carbon, the bacteria were grown in culture medium for 28 days at 120 rpm, 30°C, and their optical density was measured by spectrophotometry. Then, we tested biological oxygen demand (BOD) and chemical oxygen demand (COD) in microorganisms. Results. The highest growth rate was documented for the growth of microorganisms on either Pars 1 or Pars 2 dispersants or their mixtures with oil. However, the culture having microorganisms grown on Pars 1 had higher BOD and COD than the other two dispersants (9200 and 16800 versus 500 and 960, P < 0.05). Mixture of oil and Pars 2 as well as oil and Pars 1 dispersants showed the highest BODs and CODs, respectively. In the Bahregan province, microorganisms grown on Pars 2 had maximum amount of BOD and COD in comparison with Pars 1 and Gamlen dispersants (7100 and 15200 versus 6000 and 10560, P < 0.05). Conclusion. Pars 1 and Pars 2 were the most effective dispersants with highest degradability comparing Gamlen. In each region, the most suitable compound for removing oil spill from offshores with least secondary contamination should be investigated. PMID:22363352

Post-Transcriptional Regulation of Urokinase-type Plasminogen Activator Receptor Expression in Lipopolysaccharide-induced Acute Lung Injury

PubMed Central

Bhandary, Yashodhar P.; Velusamy, Thirunavukkarasu; Shetty, Praveenkumar; Shetty, Rashmi S.; Idell, Steven; Cines, Douglas B.; Jain, Deepika; Bdeir, Khalil; Abraham, Edward; Tsuruta, Yuko; Shetty, Sreerama

2009-01-01

Rationale: Urokinase-type plasminogen activator (uPA) receptor (uPAR) is required for the recruitment of neutrophils in response to infection. uPA induces its own expression in lung epithelial cells, which involves its interaction with cell surface uPAR. Regulation of uPAR expression is therefore crucial for uPA-mediated signaling in infectious acute lung injury (ALI). Objectives: To determine the role of uPA in uPAR expression during ALI caused by sepsis. Methods: We used Western blot, Northern blot, Northwestern assay, and immunohistochemistry. Phosphate-buffered saline– and lipopolysaccharide (LPS)-treated wild-type and uPA−/− mice were used. Measurements and Main Results: Biological activities of uPA, including proteolysis, cell adhesion, migration, proliferation, and differentiation, are dependent on its association with uPAR. Bacterial endotoxin (LPS) is a major cause of pulmonary dysfunction and infection-associated mortality. The present study shows that LPS induces uPAR expression both in vitro and in vivo, and that the mechanism involves post-transcriptional stabilization of uPAR mRNA by reciprocal interaction of phosphoglycerate kinase (PGK) and heterogeneous nuclear ribonucleoprotein C (hnRNPC) with uPAR mRNA coding region and 3′ untranslated region determinants, respectively. The process involves tyrosine phosphorylation of PGK and hnRNPC. uPA−/− mice failed to induce uPAR expression after LPS treatment. In these mice, LPS treatment failed to alter the binding of PGK and hnRNPC protein with uPAR mRNA due to lack of tyrosine phosphorylation. Conclusions: Our study shows that induction of LPS-mediated uPAR expression is mediated through tyrosine phosphorylation of PGK and hnRNPC. This involves expression of uPA as an obligate intermediary. PMID:19029002

PAR(2) expression in peripheral blood monocytes of patients with rheumatoid arthritis.

PubMed

Crilly, A; Burns, E; Nickdel, M B; Lockhart, J C; Perry, M E; Ferrell, P W; Baxter, D; Dale, J; Dunning, L; Wilson, H; Nijjar, J S; Gracie, J A; Ferrell, W R; McInnes, I B

2012-06-01

Proteinase-activated receptor 2 (PAR(2)) is a G protein-coupled receptor activated by serine proteinases with proinflammatory activity. A study was undertaken to investigate the presence and functional significance of PAR(2) expression on rheumatoid arthritis (RA)-derived leucocyte subsets. Venous blood was obtained from patients with RA and osteoarthritis (OA) as well as healthy control subjects. Surface expression of PAR(2) on peripheral blood mononuclear cells (PBMCs) was analysed by flow cytometry and interleukin 6 (IL-6) generation by ELISA. Patients with RA had elevated but variable surface expression of PAR(2) on CD14+ monocytes compared with control subjects (median (1st to 3rd quartiles) 1.76% (0.86-4.10%) vs 0.06% (0.03-0.81%), p<0.0001). CD3+ T cells showed a similar pattern with significantly higher PAR(2) expression in patients with RA compared with controls (3.05% (0.36-11.82%) vs 0.08% (0.02-0.28%), p<0.0001). For both subsets, PAR(2) expression was significantly higher (p<0.00001) in patients with high levels of disease activity: PAR(2) expression for both CD14+ and CD3+ cells correlated to C reactive protein and erythrocyte sedimentation rate. Furthermore, in a cohort of patients with newly diagnosed RA, elevated PAR(2) expression in both CD14+ and CD3+ cells was significantly reduced 3 months after methotrexate or sulfasalazine treatment and this reduction correlated significantly with the reduction in the 28-joint Disease Activity Scale score (p<0.05). PAR(2) expression on cells from patients with OA was low, similar to levels seen in control subjects. Generation of IL-6 by monocytes in response to a selective PAR(2) agonist was significantly greater in patients with RA than in patients with OA and control subjects (p<0.05). These findings are consistent with a pathogenic role for PAR(2) in RA.

Estradiol attenuates EGF-induced rapid uPAR mobilization and cell migration via the G-protein-coupled receptor 30 in ovarian cancer cells.

PubMed

Henic, Emir; Noskova, Vera; Høyer-Hansen, Gunilla; Hansson, Stefan; Casslén, Bertil

2009-02-01

Epidermal growth factor (EGF) stimulates proliferation and migration in ovarian cancer cells, and high tumor expression of the EGF system correlates with poor prognosis. Epidermal growth factor upregulates urokinase plasminogen activator receptor (uPAR) on the cell surface via 3 distinct mechanisms: rapid mobilization of uPAR from detergent-resistant domains, increased mRNA, and decreased degradation. G-protein-coupled receptor 30 (GPR30) is a newly identified membrane estrogen receptor (ER).The objective of this study was to explore the effects of 17beta-estradiol (E(2)) on uPAR expression and cell migration in ovarian cancer cells and further to identify the ER involved.We used 7 ovarian cancer cell lines, cell migration assay, cellular binding of (125)I-uPA, cellular degradation of (125)I-uPA/PAI-1 complex, enzyme-linked immunosorbent assay for uPAR, solid-phase enzyme immunoassay for ERalpha, and quantitative polymerase chain reaction. Estradiol attenuates the stimulatory effect of EGF on cell migration and uPAR expression. Specifically, E(2) reduces the very rapid increase of detergent extractable uPAR, which occurs within minutes of EGF stimulation and probably represents mobilization of uPAR from detergent-resistant domains such as lipid rafts. Estradiol influenced neither the amount of uPAR mRNA nor the rate of uPAR degradation or solubilization. The nuclear ER antagonists ICI 182780 and tamoxifen, which are GPR30 agonists, as well as the specifically constructed GPR30 agonist G1, mimicked the effect of E(2) on uPAR expression and cell migration. OVCAR-3 cells express mRNA for GPR30.Estradiol attenuates EGF-induced mobilization of ligated uPAR from detergent-resistant domains and subsequent migration in ovarian cancer cells. The response to various ER ligands indicates that this effect is mediated via the membrane ER GPR30.

PAR2 expression in peripheral blood monocytes of patients with rheumatoid arthritis

PubMed Central

Crilly, A; Burns, E; Nickdel, M B; Lockhart, J C; Perry, M E; Ferrell, P W; Baxter, D; Dale, J; Dunning, L; Wilson, H; Nijjar, J S; Gracie, J A; Ferrell, W R; McInnes, I B

2012-01-01

Objectives Proteinase-activated receptor 2 (PAR2) is a G protein-coupled receptor activated by serine proteinases with proinflammatory activity. A study was undertaken to investigate the presence and functional significance of PAR2 expression on rheumatoid arthritis (RA)-derived leucocyte subsets. Methods Venous blood was obtained from patients with RA and osteoarthritis (OA) as well as healthy control subjects. Surface expression of PAR2 on peripheral blood mononuclear cells (PBMCs) was analysed by flow cytometry and interleukin 6 (IL-6) generation by ELISA. Results Patients with RA had elevated but variable surface expression of PAR2 on CD14+ monocytes compared with control subjects (median (1st to 3rd quartiles) 1.76% (0.86–4.10%) vs 0.06% (0.03–0.81%), p<0.0001). CD3+ T cells showed a similar pattern with significantly higher PAR2 expression in patients with RA compared with controls (3.05% (0.36–11.82%) vs 0.08% (0.02–0.28%), p<0.0001). For both subsets, PAR2 expression was significantly higher (p<0.00001) in patients with high levels of disease activity: PAR2 expression for both CD14+ and CD3+ cells correlated to C reactive protein and erythrocyte sedimentation rate. Furthermore, in a cohort of patients with newly diagnosed RA, elevated PAR2 expression in both CD14+ and CD3+ cells was significantly reduced 3 months after methotrexate or sulfasalazine treatment and this reduction correlated significantly with the reduction in the 28-joint Disease Activity Scale score (p<0.05). PAR2 expression on cells from patients with OA was low, similar to levels seen in control subjects. Generation of IL-6 by monocytes in response to a selective PAR2 agonist was significantly greater in patients with RA than in patients with OA and control subjects (p<0.05). Conclusions These findings are consistent with a pathogenic role for PAR2 in RA. PMID:22294633

Protease-activated receptor 2 activation of myeloid dendritic cells regulates allergic airway inflammation

PubMed Central

2011-01-01

Background A common characteristic of allergens is that they contain proteases that can activate protease-activated receptor (PAR-2); however the mechanism by which PAR-2 regulates allergic airway inflammation is unclear. Methods Mice (wild type and PAR-2-deficient) were sensitized using German cockroach (GC) feces (frass), the isolated protease from GC frass, or through adoptive transfer of GC frass-treated bone marrow-derived dendritic cells (BMDC) and measurements of airway inflammation (cellular infiltration, cytokine expression, and mucin production), serum IgE levels and airway hyperresponsiveness (AHR) were assessed. BMDC were cultured, treated with GC frass and assessed for cytokine production. PAR-2 expression on pulmonary mDCs was determined by flow cytometry. Results Exposure to GC frass induced AHR and airway inflammation in wild type mice; however PAR-2-deficient mice had significantly attenuated responses. To directly investigate the role of the protease, we isolated the protease from GC frass and administered the endotoxin-free protease into the airways of mice in the presence of OVA. GC frass proteases were sufficient to promote the development of AHR, serum IgE, and Th2 cytokine production. PAR-2 expression on mDC was upregulated following GC frass exposure, but the presence of a functional PAR-2 did not alter antigen uptake. To determine if PAR-2 activation led to differential cytokine production, we cultured BMDC in the presence of GM-CSF and treated these cells ex vivo with GC frass. PAR-2-deficient BMDC released significantly less IL-6, IL-23 and TNFα compared to BMDC from wild type mice, suggesting PAR-2 activation was important in Th2/Th17 skewing cytokine production. To determine the role for PAR-2 on mDCs on the initiation of allergic airway inflammation, BMDCs from wild type and PAR-2-deficient mice were treated in the presence or absence of GC frass and then adoptively transferred into the airway of wild type mice. Importantly, GC frass-stimulated wild type BMDCs were sufficient to induce AHR and allergic airway inflammation, while GC frass-stimulated PAR-2-deficient BMDC had attenuated responses. Conclusions Together these data suggest an important role for allergen activation of PAR-2 on mDCs in mediating Th2/Th17 cytokine production and allergic airway responses. PMID:21936897

The Transcription Factor Orthodenticle Homeobox 2 Influences Axonal Projections and Vulnerability of Midbrain Dopaminergic Neurons

ERIC Educational Resources Information Center

Chung, Chee Yeun; Licznerski, Pawel; Alavian, Kambiz N.; Simeone, Antonio; Lin, Zhicheng; Martin, Eden; Vance, Jeffery; Isacson, Ole

2010-01-01

Two adjacent groups of midbrain dopaminergic neurons, A9 (substantia nigra pars compacta) and A10 (ventral tegmental area), have distinct projections and exhibit differential vulnerability in Parkinson's disease. Little is known about transcription factors that influence midbrain dopaminergic subgroup phenotypes or their potential role in disease.…

Nonarteritic anterior ischemic optic neuropathy following pars plana vitrectomy for macular hole treatment: case report.

PubMed

Cunha, Leonardo Provetti; Cunha, Luciana Virgínia Ferreira Costa; Costa, Carolina Ferreira; Monteiro, Mário Luiz Ribeiro

2016-01-01

Herein, we report a case of nonarteritic anterior ischemic optic neuropathy (NAION) following uneventful pars plana vitrectomy for macular hole treatment. A 56-year-old previously healthy woman presented with a full-thickness macular hole in right eye (OD) and small cup-to-disc ratios in both eyes. Five days after surgery, she noticed sudden painless loss of vision in OD and was found to have an afferent pupillary defect and intraocular pressure of 29 mmHg. Fundus examination showed right optic disc edema and the resolution of a macular hole with an inferior altitudinal visual field defect. Erythrocyte sedimentation rate, C-reactive protein levels, and general physical examination findings were normal. She was treated with hypotensive eyedrops and oral prednisone, resulting in mild visual improvement and a pale optic disc. A combination of face-down position and increased intraocular pressure due to a small optic disc cup were considered as potential mechanisms underlying NAION in the present case. Vitreoretinal surgeons should be aware of NAION as a potentially serious complication and be able to recognize associated risk factors and clinical findings.

Poly(ADP-ribosylation) is present in murine sciatic nerve fibers and is altered in a Charcot-Marie-Tooth-1E neurodegenerative model

PubMed Central

Romeo Cardeillac, Carlos J.; Cal Castillo, Karina B.; Vilchez Larrea, Salomé C.; Sotelo Sosa, José R.; Folle Ungo, Gustavo A.; Fernández Villamil, Silvia H.

2017-01-01

Background Poly-ADP-ribose (PAR) is a polymer synthesized by poly-ADP-ribose polymerases (PARPs) as a postranslational protein modification and catabolized mainly by poly-ADP-ribose glycohydrolase (PARG). In spite of the existence of cytoplasmic PARPs and PARG, research has been focused on nuclear PARPs and PAR, demonstrating roles in the maintenance of chromatin architecture and the participation in DNA damage responses and transcriptional regulation. We have recently detected non-nuclear PAR structurally and functionally associated to the E-cadherin rich zonula adherens and the actin cytoskeleton of VERO epithelial cells. Myelinating Schwann cells (SC) are stabilized by E-cadherin rich autotypic adherens junctions (AJ). We wondered whether PAR would map to these regions. Besides, we have demonstrated an altered microfilament pattern in peripheral nerves of Trembler-J (Tr-J) model of CMT1-E. We hypothesized that cytoplasmic PAR would accompany such modified F-actin pattern. Methods Wild-type (WT) and Tr-J mice sciatic nerves cryosections were subjected to immunohistofluorescence with anti-PAR antibodies (including antibody validation), F-actin detection with a phalloidin probe and DAPI/DNA counterstaining. Confocal image stacks were subjected to a colocalization highlighter and to semi-quantitative image analysis. Results We have shown for the first time the presence of PAR in sciatic nerves. Cytoplasmic PAR colocalized with F-actin at non-compact myelin regions in WT nerves. Moreover, in Tr-J, cytoplasmic PAR was augmented in close correlation with actin. In addition, nuclear PAR was detected in WT SC and was moderately increased in Tr-J SC. Discussion The presence of PAR associated to non-compact myelin regions (which constitute E-cadherin rich autotypic AJ/actin anchorage regions) and the co-alterations experienced by PAR and the actin cytoskeleton in epithelium and nerves, suggest that PAR may be a constitutive component of AJ/actin anchorage regions. Is PAR stabilizing the AJ-actin complexes? This question has strong implications in structural cell biology and cell signaling networks. Moreover, if PAR played a stabilizing role, such stabilization could participate in the physiological control of axonal branching. PARP and PAR alterations exist in several neurodegenerative pathologies including Alzheimer’s, Parkinson’s and Hungtington’s diseases. Conversely, PARP inhibition decreases PAR and promotes neurite outgrowth in cortical neurons in vitro. Coherently, the PARP inhibitor XAV939 improves myelination in vitro, ex vivo and in vivo. Until now such results have been interpreted in terms of nuclear PARP activity. Our results indicate for the first time the presence of PARylation in peripheral nerve fibers, in a healthy environment. Besides, we have evidenced a PARylation increase in Tr-J, suggesting that the involvement of cytoplasmic PARPs and PARylation in normal and neurodegenerative conditions should be re-evaluated. PMID:28503382

Activation of PAR-1/NADPH oxidase/ROS signaling pathways is crucial for the thrombin-induced sFlt-1 production in extravillous trophoblasts: possible involvement in the pathogenesis of preeclampsia.

PubMed

Huang, Qi-Tao; Chen, Jian-Hong; Hang, Li-Lin; Liu, Shi-San; Zhong, Mei

2015-01-01

Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT). An EVT cell line (HRT-8/SVneo) was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA) directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future. © 2015 S. Karger AG, Basel.

Excitation of mouse superficial dorsal horn neurons by histamine and/or PAR-2 agonist: potential role in itch.

PubMed

Akiyama, Tasuku; Carstens, Mirela Iodi; Carstens, E

2009-10-01

Recent studies have suggested the existence of separate transduction mechanisms and sensory pathways for histamine and nonhistaminergic types of itch. We studied whether histamine and an agonist of the protease-activated receptor (PAR)-2, associated with nonhistaminergic itch, excite murine dorsal horn neurons. Single units were recorded in superficial lumbar dorsal horn of adult ICR mice anesthetized with pentobarbital. Unit activity was searched using a small intradermal hindpaw injection of histamine or the PAR-2 agonist SLIGRL-NH2. Isolated units were subsequently challenged with intradermal histamine followed by SLIGRL-NH2 (each 50 microg/1 microl) or reverse order, followed by mechanical, thermal, and algogenic stimuli. Forty-three units were classified as wide dynamic range (62%), nociceptive specific (22%), or mechano insensitive (16%). Twenty units gave prolonged (mean, 10 min) discharges to intradermal injection of histamine; 76% responded to subsequent SLIGRL-NH2, often more briefly. Units additionally responded to noxious heat (63%), cooling (43%), topical mustard oil (53%), and intradermal capsaicin (67%). Twenty-two other units gave prolonged (mean, 5 min) responses to initial intradermal injection of SLIGRL-NH2; 85% responded to subsequent intradermal histamine. They also responded to noxious heat (75%), mustard oil (93%), capsaicin (63%), and one to cooling. Most superficial dorsal horn neurons were excited by both histamine and the PAR-2 agonist, suggesting overlapping pathways for histamine- and non-histamine-mediated itch. Because the large majority of pruritogen-responsive neurons also responded to noxious stimuli, itch may be signaled at least partly by a population code.

Improving the precision of lake ecosystem metabolism estimates by identifying predictors of model uncertainty

USGS Publications Warehouse

Rose, Kevin C.; Winslow, Luke A.; Read, Jordan S.; Read, Emily K.; Solomon, Christopher T.; Adrian, Rita; Hanson, Paul C.

2014-01-01

Diel changes in dissolved oxygen are often used to estimate gross primary production (GPP) and ecosystem respiration (ER) in aquatic ecosystems. Despite the widespread use of this approach to understand ecosystem metabolism, we are only beginning to understand the degree and underlying causes of uncertainty for metabolism model parameter estimates. Here, we present a novel approach to improve the precision and accuracy of ecosystem metabolism estimates by identifying physical metrics that indicate when metabolism estimates are highly uncertain. Using datasets from seventeen instrumented GLEON (Global Lake Ecological Observatory Network) lakes, we discovered that many physical characteristics correlated with uncertainty, including PAR (photosynthetically active radiation, 400-700 nm), daily variance in Schmidt stability, and wind speed. Low PAR was a consistent predictor of high variance in GPP model parameters, but also corresponded with low ER model parameter variance. We identified a threshold (30% of clear sky PAR) below which GPP parameter variance increased rapidly and was significantly greater in nearly all lakes compared with variance on days with PAR levels above this threshold. The relationship between daily variance in Schmidt stability and GPP model parameter variance depended on trophic status, whereas daily variance in Schmidt stability was consistently positively related to ER model parameter variance. Wind speeds in the range of ~0.8-3 m s–1 were consistent predictors of high variance for both GPP and ER model parameters, with greater uncertainty in eutrophic lakes. Our findings can be used to reduce ecosystem metabolism model parameter uncertainty and identify potential sources of that uncertainty.

High energy helion scattering: A ``model-independent'' analysis

NASA Astrophysics Data System (ADS)

Djaloeis, A.; Gopal, S.

1981-03-01

Angular distributions of helions elastically scattered from 24Mg, 58Ni, 90Zr and 120Sn at Eτ = 130 MeV have been subjected to a "model-independent" analysis in the framework of the optical model. The real part of the optical potential was represented by a spline-function; volume and surface absorptions were considered. Both the shallow and the deep families of the helion optical potential were investigated. The spline potentials are found to deviate from the Woods-Saxon shape. The experimental data are well described by optical potentials with either a volume or a surface absorption. However, the volume absorption consistently gives better fits. For 24Mg, 90Zr and 120Sn both shallow and deep potential families result in comparable fit qualities. For 58Ni the discrete ambiguity is resolved in favour of the shallow family. From the analysis the values of the rms radius of matter distribution have been extracted.

12 CFR 925.19 - Par value and price of stock.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Par value and price of stock. 925.19 Section... ASSOCIATES MEMBERS OF THE BANKS Stock Requirements § 925.19 Par value and price of stock. The capital stock of each Bank shall be sold at par, unless the Board has fixed a higher price. ...

[Pseudoallergies].

PubMed

Bernardini, R; Novembre, E; Lombardi, E; Monaco, M G; Monte, M T; Pucci, N; Rossi, M E; Vierucci, A

2001-01-01

Pseudo-allergic-reactions (PAR) are clinical manifestations including urticaria, angioedema, conjunctivitis, rhinitis, asthma, and anaphylaxis. The prevalence of PAR ranges from 0.1% to 75% according to various studies. The pathogenetic mechanism of these diseases is not immunologically mediated. Food, additives, and drugs are the main responsibilities for PAR. The diagnosis of PAR is characterized by the absence of specific IgE for the suspected products. The absence of immunological mechanisms is confirmed by in vitro and in vivo tests. The treatment of PAR is similar to that of allergic diseases (antihistamine drugs, steroids, B2 agonists, epinephrine).

Brulure par Plaque de Bistouri Electrique: a Propos de Quatre Cas

PubMed Central

Khales, A.; Achbouk, A.; Belmir, R.; Cherkab, L.; Ennouhi, M.A.; Ababou, K.; Ihrai, H.

2010-01-01

Summary La brûlure par plaque de bistouri électrique est un accident rare mais grave par la profondeur de la lésion et par sa localisation, surtout quand qu’elle survient dans un contexte chirurgical dont le vécu reste difficile de la part du malade et du chirurgien. Cette brûlure bien que imprévisible reste grave par la profondeur et la localisation de la brûlure et par sa survenue dans un contexte opératoire, chez des patients malades. La prise en charge de la brûlure doit se faire en milieu spécialisé. La prévention reste le seul moyen d’éviter ce type d’accident. PMID:21991216

Oil palm land conversion in Pará, Brazil, from 2006-2014: evaluating the 2010 Brazilian Sustainable Palm Oil Production Program

NASA Astrophysics Data System (ADS)

Benami, E.; Curran, L. M.; Cochrane, M.; Venturieri, A.; Franco, R.; Kneipp, J.; Swartos, A.

2018-03-01

Global models of biophysical suitability for oil palm consistently rank Brazil as having the greatest potential for expansion, with estimates as high as 238 Mha of suitable lands. In 2010, Brazil launched the Sustainable Palm Oil Production Program (SPOPP) to incentivize oil palm development without deforestation on as much as 30 Mha. Here we examine oil palm expansion before and after the SPOPP’s launch. In Pará, the major oil palm producing state in Brazil, we analyze the extent and change in oil palm cultivation from 2006-2014 using satellite imagery, ground-truthed verification, site-based interviews, and rural environmental (land) registration data. Between 2006-2014, oil palm area (≥9 ha) expanded >200% to ~219 000 ha. Of the ~148 000 ha of oil palm developed, ~91% converted pasturelands while ~8% replaced natural vegetation, including intact and secondary forests. Although >80% of all oil palm parcels rest <0.5 km from intact forests, direct conversion of intact forests declined from ~4% pre-SPOPP (2006-2010) to <1% post-SPOPP (2010-2014). Despite low and declining deforestation rates associated with oil palm expansion in Pará, our results also show a low area of oil palm development overall compared with reported land suitability. To explore potential contributing factors, we conducted semi-structured interviews with researchers, company representatives, and government officials involved in the sector to characterize the perceived factors influencing oil palm development and the role of agro-ecological suitability mapping among them. Interviews indicated that: (1) individual effects of suitability mapping efforts to encourage oil palm expansion on cleared areas, i.e. without deforestation, cannot be disentangled from pre-existing public and private deforestation reduction initiatives; and, (2) socio-economic constraints, e.g. high relative production costs and limited familiarity with this crop, appear to partially explain the major discrepancy between estimated potential suitable areas with realized oil palm development.

Elongation factor-2 kinase regulates TG2/β1 integrin/Src/uPAR pathway and epithelial–mesenchymal transition mediating pancreatic cancer cells invasion

PubMed Central

Ashour, Ahmed A; Gurbuz, Nilgun; Alpay, Sultan Neslihan; Abdel-Aziz, Abdel-Aziz H; Mansour, Ahmed M; Huo, Longfei; Ozpolat, Bulent

2014-01-01

Pancreatic ductal adenocarcinoma is one of the lethal cancers with extensive local tumour invasion, metastasis, early systemic dissemination and poorest prognosis. Thus, understanding the mechanisms regulating invasion/metastasis and epithelial–mesenchymal transition (EMT), is the key for developing effective therapeutic strategies for pancreatic cancer (PaCa). Eukaryotic elongation factor-2 kinase (eEF-2K) is an atypical kinase that we found to be highly up-regulated in PaCa cells. However, its role in PaCa invasion/progression remains unknown. Here, we investigated the role of eEF-2K in cellular invasion, and we found that down-regulation of eEF-2K, by siRNA or rottlerin, displays impairment of PaCa cells invasion/migration, with significant decreases in the expression of tissue transglutaminase (TG2), the multifunctional enzyme implicated in regulation of cell attachment, motility and survival. These events were associated with reductions in β1 integrin/uPAR/MMP-2 expressions as well as decrease in Src activity. Furthermore, inhibition of eEF-2K/TG2 axis suppresses the EMT, as demonstrated by the modulation of the zinc finger transcription factors, ZEB1/Snail, and the tight junction proteins, claudins. Importantly, while eEF-2K silencing recapitulates the rottlerin-induced inhibition of invasion and correlated events, eEF-2K overexpression, by lentivirus-based expression system, suppresses such rottlerin effects and potentiates PaCa cells invasion/migration capability. Collectively, our results show, for the first time, that eEF-2K is involved in regulation of the invasive phenotype of PaCa cells through promoting a new signalling pathway, which is mediated by TG2/β1 integrin/Src/uPAR/MMP-2, and the induction of EMT biomarkers which enhance cancer cell motility and metastatic potential. Thus, eEF-2K could represent a novel potential therapeutic target in pancreatic cancer. PMID:25215932

Hydrogen sulfide donors alleviate itch secondary to the activation of type-2 protease activated receptors (PAR-2) in mice.

PubMed

Coavoy-Sánchez, S A; Rodrigues, L; Teixeira, S A; Soares, A G; Torregrossa, R; Wood, M E; Whiteman, M; Costa, S K P; Muscará, M N

2016-11-01

Hydrogen sulfide (H 2 S) has been highlighted as an endogenous signaling molecule and we have previously found that it can inhibit histamine-mediated itching. Pruritus is the most common symptom of cutaneous diseases and anti-histamines are the usual treatment; however, anti-histamine-resistant pruritus is common in some clinical settings. In this way, the involvement of mediators other than histamine in the context of pruritus requires new therapeutic targets. Considering that the activation of proteinase-activated receptor 2 (PAR-2) is involved in pruritus both in rodents and humans, in this study we investigated the effect of H 2 S donors on the acute scratching behavior mediated by PAR-2 activation in mice, as well as some of the possible pharmacological mechanisms involved. The intradermal injection of the PAR-2 peptide agonist SLIGRL-NH 2 (8-80nmol) caused a dose-dependent scratching that was unaffected by intraperitoneal pre-treatment with the histamine H1 antagonist pyrilamine (30mg/kg). Co-injection of SLIGRL-NH 2 (40nmol) with either the slow-release H 2 S donor GYY4137 (1 and 3nmol) or the spontaneous donor NaHS (1 and 0.3nmol) significantly reduced pruritus. Co-treatment with the K ATP channel blocker glibenclamide (200nmol) or the nitric oxide (NO) donor sodium nitroprusside (10nmol) abolished the antipruritic effects of NaHS; however, the specific soluble guanylyl cyclase inhibitor ODQ (30μg) had no significant effects. The transient receptor potential ankyrin type 1 (TRPA1) antagonist HC-030031 (20μg) significantly reduced SLIGRL-NH 2 -induced pruritus; however pruritus induced by the TRPA1 agonist AITC (1000nmol) was unaffected by NaHS. Based on these data, we conclude that pruritus secondary to PAR-2 activation can be reduced by H 2 S, which acts through K ATP channel opening and involves NO in a cyclic guanosine monophosphate (cGMP)-independent manner. Furthermore, TRPA1 receptors mediate the pruritus induced by activation of PAR-2, but H 2 S does not interfere with this pathway. These results provide additional support for the development of new therapeutical alternatives, mainly intended for treatment of pruritus in patients unresponsive to anti-histamines. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physicochemical characteristics and gastrointestinal absorption behaviors of S-propargyl-cysteine, a potential new drug candidate for cardiovascular protection and antitumor treatment.

PubMed

Ma, Guo; Zhang, Lin; Zhang, Peng; Bao, Xingfei; Zhou, Ning; Shi, Qingling; Zheng, Yuanting; Liu, Hongrui; Bu, Fengjiao; Zhang, Ying; Huang, Wenjie; Wang, Fen; Zhu, Yizhun; Cai, Weimin

2015-04-01

1. As a potential new drug candidate for cardiovascular protection and antitumor treatment, the physicochemical properties, gastrointestinal (GI) absorption behaviors and mechanisms of S-propargyl-cysteine (SPRC) were investigated in this study. 2. SPRC exhibited favorable solubility in aqueous media. The log P and log D values were low (≤1.93 ± 0.08). The pKa in the acidic and basic regions was 2.08 ± 0.02 and 8.72 ± 0.03, respectively. The isoelectric point was 5.40 ± 0.02. SPRC was stable in the rat GI fluids, and showed no obvious adsorption and metabolism in the rat GI tract. 3. SPRC displayed poor gastric absorption and favorable intestinal absorption in the rat in situ GI perfusion model. Absorption rate constants (ka), hourly absorption percentage (P) and apparent permeability coefficient (Papp) of SPRC in the small intestine were ≥0.77 ± 0.06 h(-1), 59.25 ± 4.02% and (7.99 ± 0.88) × 10(-5 )cm/s, respectively. Absorption of SPRC exhibited a certain dependence on physiological pH and absorption region. Absorption of SPRC was not inhibited by l-methionine and 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid. 4. SPRC showed favorable oral absorption. It can be categorized as a BCS class I drug. The membrane pore transport appeared to be one of the predominant absorption modes for SPRC.

PAR-2 inhibition reverses experimental pulmonary hypertension.

PubMed

Kwapiszewska, Grazyna; Markart, Philipp; Dahal, Bhola Kumar; Kojonazarov, Baktybek; Marsh, Leigh Matthew; Schermuly, Ralph Theo; Taube, Christian; Meinhardt, Andreas; Ghofrani, Hossein Ardeschir; Steinhoff, Martin; Seeger, Werner; Preissner, Klaus Theo; Olschewski, Andrea; Weissmann, Norbert; Wygrecka, Malgorzata

2012-04-27

A hallmark of the vascular remodeling process underlying pulmonary hypertension (PH) is the aberrant proliferation and migration of pulmonary arterial smooth muscle cells (PASMC). Accumulating evidence suggests that mast cell mediators play a role in the pathogenesis of PH. In the present study we investigated the importance of protease-activated receptor (PAR)-2 and its ligand mast cell tryptase in the development of PH. Our results revealed strong increase in PAR-2 and tryptase expression in the lungs of idiopathic pulmonary arterial hypertension (IPAH) patients, hypoxia-exposed mice, and monocrotaline (MCT)-treated rats. Elevated tryptase levels were also detected in plasma samples from IPAH patients. Hypoxia and platelet-derived growth factor (PDGF)-BB upregulated PAR-2 expression in PASMC. This effect was reversed by HIF (hypoxia inducible factor)-1α depletion, PDGF-BB neutralizing antibody, or the PDGF-BB receptor antagonist Imatinib. Attenuation of PAR-2 expression was also observed in smooth muscle cells of pulmonary vessels of mice exposed to hypoxia and rats challenged with MCT in response to Imatinib treatment. Tryptase induced PASMC proliferation and migration as well as enhanced synthesis of fibronectin and matrix metalloproteinase-2 in a PAR-2- and ERK1/2-dependent manner, suggesting that PAR-2-dependent signaling contributes to vascular remodeling by various mechanisms. Furthermore, PAR-2(-/-) mice were protected against hypoxia-induced PH, and PAR-2 antagonist application reversed established PH in the hypoxia mouse model. Our study identified a novel role of PAR-2 in vascular remodeling in the lung. Interference with this pathway may offer novel therapeutic options for the treatment of PH.

In Vitro Activity of Five Quinolones and Analysis of the Quinolone Resistance-Determining Regions of gyrA, gyrB, parC, and parE in Ureaplasma parvum and Ureaplasma urealyticum Clinical Isolates from Perinatal Patients in Japan

PubMed Central

Kawai, Yasuhiro; Nakura, Yukiko; Wakimoto, Tetsu; Nomiyama, Makoto; Tokuda, Tsugumichi; Takayanagi, Toshimitsu; Shiraishi, Jun; Wasada, Kenshi; Kitajima, Hiroyuki; Fujita, Tomio; Nakayama, Masahiro; Mitsuda, Nobuaki; Nakanishi, Isao; Takeuchi, Makoto

2015-01-01

Ureaplasma spp. cause several disorders, such as nongonococcal urethritis, miscarriage, and preterm delivery with lung infections in neonates, characterized by pathological chorioamnionitis in the placenta. Although reports on antibiotic resistance in Ureaplasma are on the rise, reports on quinolone-resistant Ureaplasma infections in Japan are limited. The purpose of this study was to determine susceptibilities to five quinolones of Ureaplasma urealyticum and Ureaplasma parvum isolated from perinatal samples in Japan and to characterize the quinolone resistance-determining regions in the gyrA, gyrB, parC, and parE genes. Out of 28 clinical Ureaplasma strains, we isolated 9 with high MICs of quinolones and found a single parC gene mutation, resulting in the change S83L. Among 158 samples, the ParC S83L mutation was found in 37 samples (23.4%), including 1 sample harboring a ParC S83L–GyrB P462S double mutant. Novel mutations of ureaplasmal ParC (S83W and S84P) were independently found in one of the samples. Homology modeling of the ParC S83W mutant suggested steric hindrance of the quinolone-binding pocket (QBP), and de novo prediction of peptide structures revealed that the ParC S84P may break/kink the formation of the α4 helix in the QBP. Further investigations are required to unravel the extent and mechanism of antibiotic resistance of Ureaplasma spp. in Japan. PMID:25645833

The use of radiolabelling techniques to measure substantivity to, and penetration into, hair of protein hydrolysates.

PubMed

Jones, R T; Chahal, S P

1997-10-01

The use of 14C-labelled amino acids enables the measurement of both the total substantivity to hair and the degree of penetration into the hair shaft of amino acid mixtures derived from complete hydrolysis of proteins. The technique utilizes the fact that direct measurement of 14C radioactivity of the treated hair detects only the surface substantivity. Total substantivity can be determined following solubilization of the hair. Data obtained for wheat amino acids show significant penetration when used to treat hair from a shampoo or conditioner formulation. A similar technique has been investigated for a wheat protein partial hydrolysate using 14CNO for radiolabelling purposes and shows that significant penetration into hair can occur. L'utilisation d'amino-acides marques au 14C permet la mesure a la fois de l'absorption totale par les cheveux et du degre de penetration dans la fibre du cheveu de melanges d'amino-acides obtenus a partir d'une hydrolyse totale de proteines. La technique utilise le fait que la mesure directe de la radioactivite du 14C des cheveux traites ne detecte que l'absorption en surface. L'absorption totale peut etre determinee apres solubilisation des cheveux. Les donnees obtenues a partir d'amino-acides de ble montrent une penetration significative lors d'une utilisation pour traiter des cheveux a partir d'une formulation de shampoing ou d'apres-shampoing. Une technique similaire a ete exploree vis-a-vis d'un hydrolysat partiel d'une proteine de ble utilisant 14CNO a des fins de marquage, et montre qu'une penetration significative dans les cheveux peut avoir lieu.

Du pompage optique laser à l'absorption saturée résolue en temps

NASA Astrophysics Data System (ADS)

Dumont, M.

The first part is a brief historical account of the beginning of lasers at the « Laboratoire de Spectroscopie Hertzienne de l'ENS » and, more precisely, of the first experiments of optical pumping with multimode lasers. The three new features (stimulated emission, coherence and saturation) are emphasized. Paragraphes 2 and 3 outline the special behaviour of monomode optical pumping (velocity selection) and of timeresolved saturated absorption. This last technique is applied to study elastic collisions (determination of the « collision Kernel ») and Raman coherence between metastable levels. The last paragraphe summarizes a semi-perturbative calculation of transients in Velocity Selective Optical Pumping (VSOP). La première partie est un survol historique de l'introduction des lasers au laboratoire de Spectroscopie Hertzienne de l'ENS et particulièrement des premières expériences de pompage optique avec un laser multimode. Les trois caractéristiques nouvelles (émission stimulée, cohérence de la lumière et saturations) sont mises en lumière. Les paragraphes 2 et 3 présentent les particularités du pompage optique par un laser monomode (sélection des vitesses atomiques) et de la technique d'absorption saturée résolue en temps. Cette dernière technique est appliquée à l'étude des collisions élastiques (détermination du « noyau de collision ») et de la cohérence Raman entre niveaux métastables. La dernière partie présente, de façon résumée, un calcul semiperturbatif des transitoires de pompage optique sélectif en vitesse (VSOP).

Manufacturing ceramic bricks with polyaluminum chloride (PAC) sludge from a water treatment plant.

PubMed

da Silva, E M; Morita, D M; Lima, A C M; Teixeira, L Girard

2015-01-01

The objective of this research work is to assess the viability of manufacturing ceramic bricks with sludge from a water treatment plant (WTP) for use in real-world applications. Sludge was collected from settling tanks at the Bolonha WTP, which is located in Belém, capital of the state of Pará, Brazil. After dewatering in drainage beds, sludge was added to the clay at a local brickworks at different mass percentages (7.6, 9.0, 11.7, 13.9 and 23.5%). Laboratory tests were performed on the bricks to assess their resistance to compression, water absorption, dimensions and visual aspects. Percentages of 7.6, 9.0, 11.7 and 13.9% (w/w) of WTP sludge presented good results in terms of resistance, which indicates that technically, ceramic bricks can be produced by incorporating up to 13.9% of WTP sludge.

Suppression of Peripheral Sympathetic Activity Underlies Protease-Activated Receptor 2-Mediated Hypotension

PubMed Central

Kim, Young-Hwan; Ahn, Duck-Sun; Joeng, Ji-Hyun

2014-01-01

Protease-activated receptor (PAR)-2 is expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although some reports have suggested involvement of a neurogenic mechanism in PAR-2-induced hypotension, the accurate mechanism remains to be elucidated. To examine this possibility, we investigated the effect of PAR-2 activation on smooth muscle contraction evoked by electrical field stimulation (EFS) in the superior mesenteric artery. In the present study, PAR-2 agonists suppressed neurogenic contractions evoked by EFS in endothelium-denuded superior mesenteric arterial strips but did not affect contraction elicited by the external application of noradrenaline (NA). However, thrombin, a potent PAR-1 agonist, had no effect on EFS-evoked contraction. Additionally, ω-conotoxin GVIA (CgTx), a selective N-type Ca2+ channel (ICa-N) blocker, significantly inhibited EFS-evoked contraction, and this blockade almost completely occluded the suppression of EFS-evoked contraction by PAR-2 agonists. Finally, PAR-2 agonists suppressed the EFS-evoked overflow of NA in endothelium-denuded rat superior mesenteric arterial strips and this suppression was nearly completely occluded by ω-CgTx. These results suggest that activation of PAR-2 may suppress peripheral sympathetic outflow by modulating activity of ICa-N which are located in peripheral sympathetic nerve terminals, which results in PAR-2-induced hypotension. PMID:25598663

Diabetes-Induced Superoxide Anion and Breakdown of the Blood-Retinal Barrier: Role of the VEGF/uPAR Pathway

PubMed Central

El-Remessy, Azza B.; Franklin, Telina; Ghaley, Nagla; Yang, Jinling; Brands, Michael W.; Caldwell, Ruth B.; Behzadian, Mohamed Ali

2013-01-01

Diabetes-induced breakdown of the blood-retinal barrier (BRB) has been linked to hyperglycemia-induced expression of vascular endothelial growth factor (VEGF) and is likely mediated by an increase in oxidative stress. We have shown that VEGF increases permeability of retinal endothelial cells (REC) by inducing expression of urokinase plasminogen activator receptor (uPAR). The purpose of this study was to define the role of superoxide anion in VEGF/uPAR expression and BRB breakdown in diabetes. Studies were performed in streptozotocin diabetic rats and mice and high glucose (HG) treated REC. The superoxide dismutase (SOD) mimetic tempol blocked diabetes-induced permeability and uPAR expression in rats and the cell permeable SOD inhibited HG-induced expression of uPAR and VEGF in REC. Inhibiting VEGFR blocked HG-induced expression of VEGF and uPAR and GSK-3β phosphorylation in REC. HG caused β-catenin translocation from the plasma membrane into the cytosol and nucleus. Treatment with HG-conditioned media increased REC paracellular permeability that was blocked by anti-uPA or anti-uPAR antibodies. Moreover, deletion of uPAR blocked diabetes-induced BRB breakdown and activation of MMP-9 in mice. Together, these data indicate that diabetes-induced oxidative stress triggers BRB breakdown by a mechanism involving uPAR expression through VEGF-induced activation of the GSK3β/β-catenin signaling pathway. PMID:23951261

PAR-1/MARK: a kinase essential for maintaining the dynamic state of microtubules.

PubMed

Hayashi, Kenji; Suzuki, Atsushi; Ohno, Shigeo

2012-01-01

The serine/threonine kinase, PAR-1, is an essential component of the evolutionary-conserved polarity-regulating system, PAR-aPKC system, which plays indispensable roles in establishing asymmetric protein distributions and cell polarity in various biological contexts (Suzuki, A. and Ohno, S. (2006). J. Cell Sci., 119: 979-987; Matenia, D. and Mandelkow, E.M. (2009). Trends Biochem. Sci., 34: 332-342). PAR-1 is also known as MARK, which phosphorylates classical microtubule-associated proteins (MAPs) and detaches MAPs from microtubules (Matenia, D. and Mandelkow, E.M. (2009). Trends Biochem. Sci., 34: 332-342). This MARK activity of PAR-1 suggests its role in microtubule (MT) dynamics, but surprisingly, only few studies have been carried out to address this issue. Here, we summarize our recent study on live imaging analysis of MT dynamics in PAR-1b-depleted cells, which clearly demonstrated the positive role of PAR-1b in maintaining MT dynamics (Hayashi, K., Suzuki, A., Hirai, S., Kurihara, Y., Hoogenraad, C.C., and Ohno, S. (2011). J. Neurosci., 31: 12094-12103). Importantly, our results further revealed the novel physiological function of PAR-1b in maintaining dendritic spine morphology in mature neurons.

Monomer–dimer dynamics and distribution of GPI-anchored uPAR are determined by cell surface protein assemblies

PubMed Central

Caiolfa, Valeria R.; Zamai, Moreno; Malengo, Gabriele; Andolfo, Annapaola; Madsen, Chris D.; Sutin, Jason; Digman, Michelle A.; Gratton, Enrico; Blasi, Francesco; Sidenius, Nicolai

2007-01-01

To search for functional links between glycosylphosphatidylinositol (GPI) protein monomer–oligomer exchange and membrane dynamics and confinement, we studied urokinase plasminogen activator (uPA) receptor (uPAR), a GPI receptor involved in the regulation of cell adhesion, migration, and proliferation. Using a functionally active fluorescent protein–uPAR in live cells, we analyzed the effect that extracellular matrix proteins and uPAR ligands have on uPAR dynamics and dimerization at the cell membrane. Vitronectin directs the recruitment of dimers and slows down the diffusion of the receptors at the basal membrane. The commitment to uPA–plasminogen activator inhibitor type 1–mediated endocytosis and recycling modifies uPAR diffusion and induces an exchange between uPAR monomers and dimers. This exchange is fully reversible. The data demonstrate that cell surface protein assemblies are important in regulating the dynamics and localization of uPAR at the cell membrane and the exchange of monomers and dimers. These results also provide a strong rationale for dynamic studies of GPI-anchored molecules in live cells at steady state and in the absence of cross-linker/clustering agents. PMID:18056417

The pars intermedia: an anatomic basis for a coordinated vascular response to female genital arousal.

PubMed

Shih, Cheryl; Cold, Christopher J; Yang, Claire C

2013-06-01

The pars intermedia is an area of the vulva that has been inconsistently described in the literature. We conducted anatomic studies to better describe the tissues and vascular structures of the pars intermedia and proposed a functional rationale of the pars intermedia in the female sexual response. Nine cadaveric vulvectomy specimens were used. Each was serially sectioned and stained with hematoxylin and eosin and Masson's trichrome. Histologic ultrastructural description of the pars intermedia. The pars intermedia contains veins traveling longitudinally in the angle of the clitoris, supported by collagen-rich stromal tissues. These veins drain the different vascular compartments of the vulva, including the clitoris, the bulbs, and labia minora; also, the interconnecting veins link the different vascular compartments. The pars intermedia is not composed of erectile tissue, distinguishing it from the erectile tissues of the corpora cavernosa of the clitoris as well as the corpus spongiosum of the clitoral (vestibular) bulbs. The venous communications of the pars intermedia, linking the erectile tissues with the other vascular compartments of the vulva, appear to provide the anatomic basis for a coordinated vascular response during female sexual arousal. © 2012 International Society for Sexual Medicine.

Structural Basis of Interaction between Urokinase-Type Plasminogen Activator and Its Receptor

PubMed Central

Barinka, Cyril; Parry, Graham; Callahan, Jennifer; Shaw, David E.; Kuo, Alice; Bdeir, Khalil; Cines, Douglas B.; Mazar, Andrew; Lubkowski, Jacek

2009-01-01

Summary Recent studies indicate that binding of urokinase-type plasminogen activator (uPA) to its high affinity receptor (uPAR), orchestrates uPAR interactions with other cellular components that play a pivotal role in diverse (patho-)physiological processes including wound healing, angiogenesis, inflammation, and cancer metastasis. However, notwithstanding the wealth of biochemical data available describing the activities of uPAR, little is known as to the exact mode of uPAR-uPA interactions and the presumed conformational changes that accompanying uPA-uPAR engagement. Here we report the crystal structure of soluble urokinase plasminogen activator receptor (suPAR), which contains the three domains of the wild-type receptor but lacks the cell surface anchoring sequence, in complex with the amino terminal fragment of urokinase-type plasminogen activator (ATF), at the resolution of 2.8 Å. We also report the 1.9 Å crystal structure of the free ATF. Our results provide a structural basis, represented by conformational changes induced in uPAR, for several published biochemical observations describing the nature of uPAR-uPA interactions and provide insight into mechanisms that may be responsible for the cellular responses induced by uPA binding. PMID:16979660

Diurnal and seasonal variations in carbon dioxide exchange in ecosystems in the Zhangye oasis area, Northwest China.

PubMed

Zhang, Lei; Sun, Rui; Xu, Ziwei; Qiao, Chen; Jiang, Guoqing

2015-01-01

Quantifying carbon dioxide exchange and understanding the response of key environmental factors in various ecosystems are critical to understanding regional carbon budgets and ecosystem behaviors. For this study, CO2 fluxes were measured in a variety of ecosystems with an eddy covariance observation matrix between June 2012 and September 2012 in the Zhangye oasis area of Northwest China. The results show distinct diurnal variations in the CO2 fluxes in vegetable field, orchard, wetland, and maize cropland. Diurnal variations of CO2 fluxes were not obvious, and their values approached zero in the sandy desert, desert steppe, and Gobi ecosystems. Additionally, daily variations in the Gross Primary Production (GPP), Ecosystem Respiration (Reco) and Net Ecosystem Exchange (NEE) were not obvious in the sandy desert, desert steppe, and Gobi ecosystems. In contrast, the distributions of the GPP, Reco, and NEE show significant daily variations, that are closely related to the development of vegetation in the maize, wetland, orchard, and vegetable field ecosystems. All of the ecosystems are characterized by their carbon absorption during the observation period. The ability to absorb CO2 differed significantly among the tested ecosystems. We also used the Michaelis-Menten equation and exponential curve fitting methods to analyze the impact of Photosynthetically Active Radiation (PAR) on the daytime CO2 flux and impact of air temperature on Reco at night. The results show that PAR is the dominant factor in controlling photosynthesis with limited solar radiation, and daytime CO2 assimilation increases rapidly with PAR. Additionally, the carbon assimilation rate was found to increase slowly with high solar radiation. The light response parameters changed with each growth stage for all of the vegetation types, and higher light response values were observed during months or stages when the plants grew quickly. Light saturation points are different for different species. Nighttime Reco increases exponentially with air temperature. High Q10 values were observed when the vegetation coverage was relatively low, and low Q10 values occurred when the vegetables grew vigorously.

Greener Pastures in Northern Queensland, Australia

NASA Technical Reports Server (NTRS)

2004-01-01

After a 19 month rainfall deficiency, heavy rainfall during January 2004 brought drought relief to much of northern Queensland. Local graziers hope for good long-term responses in pasture growth from the heavy rains. These images and maps from the Multi-angle Imaging SpectroRadiometer (MISR) portray part of Australia's Mitchell Grasslands bioregion before summer rainfall, on October 18, 2003 (left) and afterwards, on February 7, 2004 (right).

The top pair of images are natural color views from MISR's nadir camera. The green areas in the post-rainfall image highlight the growth of vegetation. The middle panels show the reflectivity of the surface over the photosynthetically active region (PAR) of visible light (400 - 700 nm), expressed as a directional-hemispherical reflectance (DHR-PAR), or albedo. That portion of the radiation that is not reflected back to the atmosphere or space is absorbed by either the vegetation or the soil. The fraction of PAR radiation absorbed by green vegetation, known as FPAR, is shown in the bottom panels. FPAR is one of the quantities that establishes the photosynthetic and carbon uptake efficiency of live vegetation. MISR's FPAR product makes use of aerosol retrievals to correct for atmospheric scattering and absorption effects, and uses plant canopy structural models to determine the partitioning of solar radiation. Both of these aspects are facilitated by the multiangular nature of the MISR measurements.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 20397 and 22028. The panels cover an area of about 290 kilometers x 228 kilometers, and utilize data from blocks 106 to 108 within World Reference System-2 path 96.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Cortical Polarity of the RING Protein PAR-2 Is Maintained by Exchange Rate Kinetics at the Cortical-Cytoplasmic Boundary.

PubMed

Arata, Yukinobu; Hiroshima, Michio; Pack, Chan-Gi; Ramanujam, Ravikrishna; Motegi, Fumio; Nakazato, Kenichi; Shindo, Yuki; Wiseman, Paul W; Sawa, Hitoshi; Kobayashi, Tetsuya J; Brandão, Hugo B; Shibata, Tatsuo; Sako, Yasushi

2016-08-23

Cell polarity arises through the spatial segregation of polarity regulators. PAR proteins are polarity regulators that localize asymmetrically to two opposing cortical domains. However, it is unclear how the spatially segregated PAR proteins interact to maintain their mutually exclusive partitioning. Here, single-molecule detection analysis in Caenorhabditis elegans embryos reveals that cortical PAR-2 diffuses only short distances, and, as a result, most PAR-2 molecules associate and dissociate from the cortex without crossing into the opposing domain. Our results show that cortical PAR-2 asymmetry is maintained by the local exchange reactions that occur at the cortical-cytoplasmic boundary. Additionally, we demonstrate that local exchange reactions are sufficient to maintain cortical asymmetry in a parameter-free mathematical model. These findings suggest that anterior and posterior PAR proteins primarily interact through the cytoplasmic pool and not via cortical diffusion. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The Polarity Protein Partitioning-defective 1 (PAR-1) Regulates Dendritic Spine Morphogenesis through Phosphorylating Postsynaptic Density Protein 95 (PSD-95)*

PubMed Central

Wu, Qian; DiBona, Victoria L.; Bernard, Laura P.; Zhang, Huaye

2012-01-01

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95. PMID:22807451

ParFit: A Python-Based Object-Oriented Program for Fitting Molecular Mechanics Parameters to ab Initio Data

DOE PAGES

Zahariev, Federico; De Silva, Nuwan; Gordon, Mark S.; ...

2017-02-23

Here, a newly created object-oriented program for automating the process of fitting molecular-mechanics parameters to ab initio data, termed ParFit, is presented. ParFit uses a hybrid of deterministic and stochastic genetic algorithms. ParFit can simultaneously handle several molecular-mechanics parameters in multiple molecules and can also apply symmetric and antisymmetric constraints on the optimized parameters. The simultaneous handling of several molecules enhances the transferability of the fitted parameters. ParFit is written in Python, uses a rich set of standard and nonstandard Python libraries, and can be run in parallel on multicore computer systems. As an example, a series of phosphine oxides,more » important for metal extraction chemistry, are parametrized using ParFit.« less

ParFit: A Python-Based Object-Oriented Program for Fitting Molecular Mechanics Parameters to ab Initio Data

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

Zahariev, Federico; De Silva, Nuwan; Gordon, Mark S.

Here, a newly created object-oriented program for automating the process of fitting molecular-mechanics parameters to ab initio data, termed ParFit, is presented. ParFit uses a hybrid of deterministic and stochastic genetic algorithms. ParFit can simultaneously handle several molecular-mechanics parameters in multiple molecules and can also apply symmetric and antisymmetric constraints on the optimized parameters. The simultaneous handling of several molecules enhances the transferability of the fitted parameters. ParFit is written in Python, uses a rich set of standard and nonstandard Python libraries, and can be run in parallel on multicore computer systems. As an example, a series of phosphine oxides,more » important for metal extraction chemistry, are parametrized using ParFit.« less

Nicotine stimulates urokinase-type plasminogen activator receptor expression and cell invasiveness through mitogen-activated protein kinase and reactive oxygen species signaling in ECV304 endothelial cells

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

Khoi, Pham Ngoc; Park, Jung Sun; Kim, Nam Ho

Urokinase-type plasminogen activator receptor (uPAR) expression is elevated during inflammation, tissue remodeling and in many human cancers. This study investigated the effect of nicotine, a major alkaloid in tobacco, on uPAR expression and cell invasiveness in ECV304 endothelial cells. Nicotine stimulated uPAR expression in a dose-dependent manner and activated extracellular signal-regulated kinases-1/2 (Erk-1/2), c-Jun amino-terminal kinase (JNK) and p38 mitogen activated protein kinase (MAPK). Specific inhibitors of MEK-1 (PD98059) and JNK (SP600125) inhibited the nicotine-induced uPAR expression, while the p38 MAPK inhibitor SB203580 did not. Expression vectors encoding dominant negative MEK-1 (pMCL-K97M) and JNK (TAM67) also prevented nicotine-induced uPAR promotermore » activity. The intracellular hydrogen peroxide (H{sub 2}O{sub 2}) content was increased by nicotine treatment. The antioxidant N-acetylcysteine prevented nicotine-activated production of reactive oxygen species (ROS) and uPAR expression. Furthermore, exogenous H{sub 2}O{sub 2} increased uPAR mRNA expression. Deleted and site-directed mutagenesis demonstrated the involvement of the binding sites of transcription factor nuclear factor-kappaB (NF-κB) and activator protein (AP)-1 in the nicotine-induced uPAR expression. Studies with expression vectors encoding mutated NF-κB signaling molecules and AP-1 decoy confirmed that NF-κB and AP-1 were essential for the nicotine-stimulated uPAR expression. MAPK (Erk-1/2 and JNK) and ROS functioned as upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. In addition, ECV304 endothelial cells treated with nicotine displayed markedly enhanced invasiveness, which was partially abrogated by uPAR neutralizing antibodies. The data indicate that nicotine induces uPAR expression via the MAPK/AP-1 and ROS/NF-κB signaling pathways and, in turn, stimulates invasiveness in human ECV304 endothelial cells. -- Highlights: ► Endothelial cells treated with nicotine displayed enhanced invasiveness. ► Nicotine induces uPAR expression and, in turn, stimulates invasiveness. ► MAPK/AP-1 and ROS/NF-κB signals are involved in nicotine-induced uPAR.« less

Three-dimensional mechanisms of macro-to-micro-scale transport and absorption enhancement by gut villi motions

NASA Astrophysics Data System (ADS)

Wang, Yanxing; Brasseur, James G.

2017-06-01

We evaluate the potential for physiological control of intestinal absorption by the generation of "micromixing layers" (MMLs) induced by coordinated motions of mucosal villi coupled with lumen-scale "macro" eddying motions generated by gut motility. To this end, we apply a three-dimensional (3D) multigrid lattice-Boltzmann model of a lid-driven macroscale cavity flow with microscale fingerlike protuberances at the lower surface. Integrated with a previous 2D study of leaflike villi, we generalize to 3D the 2D mechanisms found there to enhance nutrient absorption by controlled villi motility. In three dimensions, increased lateral spacing within villi within groups that move axially with the macroeddy reduces MML strength and absorptive enhancement relative to two dimensions. However, lateral villi motions create helical 3D particle trajectories that enhance absorption rate to the level of axially moving 2D leaflike villi. The 3D enhancements are associated with interesting fundamental adjustments to 2D micro-macro-motility coordination mechanisms and imply a refined potential for physiological or pharmaceutical control of intestinal absorption.

Allelopathic potential and systematic evaluation of organic extracts from Canavalia ensiformis leaves (Jack beans).

PubMed

Santos, Sonia; de Moraes, Maria de Lourdes Leite; da Silva Souza Filho, Antonio Pedro; Rezende, Maria Olímpia Oliveira

2005-01-01

This article describes the assessment of possible allelopathic potential of organic extracts obtained from leaves of Canavalia ensiformis under laboratory conditions. Furthermore, a systematic evaluation of these extracts was carried out using specific protocols developed in capillary electrophoresis (CE) to determine some groups of secondary metabolites. After the identification and quantification of compounds, the effects of compounds on germination of some common weeds was investigated, which are becoming a real problem in pastures in the state of Pará, Brazil.

TGF-beta inhibits IL-1beta-activated PAR-2 expression through multiple pathways in human primary synovial cells.

PubMed

Tsai, Shin-Han; Sheu, Ming-Thau; Liang, Yu-Chih; Cheng, Hsiu-Tan; Fang, Sheng-Shiung; Chen, Chien-Ho

2009-10-23

To investigate the mechanism how Transforming growth factor-beta(TGF-beta) represses Interleukin-1beta (IL-1beta)-induced Proteinase-Activated Receptor-2 (PAR-2) expression in human primary synovial cells (hPSCs). Human chondrocytes and hPSCs isolated from cartilages and synovium of Osteoarthritis (OA) patients were cultured with 10% fetal bovine serum media or serum free media before treatment with IL-1beta, TGF-beta1, or Connective tissue growth factor (CTGF). The expression of PAR-2 was detected using reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting. Collagen zymography was performed to assess the activity of Matrix metalloproteinases-13 (MMP-13). It was demonstrated that IL-1beta induces PAR-2 expression via p38 pathway in hPSCs. This induction can be repressed by TGF-beta and was observed to persist for at least 48 hrs, suggesting that TGF-beta inhibits PAR-2 expression through multiple pathways. First of all, TGF-beta was able to inhibit PAR-2 activity by inhibiting IL-1beta-induced p38 signal transduction and secondly the inhibition was also indirectly due to MMP-13 inactivation. Finally, TGF-beta was able to induce CTGF, and in turn CTGF represses PAR-2 expression by inhibiting IL-1beta-induced phospho-p38 level. TGF-beta could prevent OA from progression with the anabolic ability to induce CTGF production to maintain extracellular matrix (ECM) integrity and to down regulate PAR-2 expression, and the anti-catabolic ability to induce Tissue inhibitors of metalloproteinase-3 (TIMP-3) production to inhibit MMPs leading to avoid PAR-2 over-expression. Because IL-1beta-induced PAR-2 expressed in hPSCs might play a significantly important role in early phase of OA, PAR-2 repression by exogenous TGF-beta or other agents might be an ideal therapeutic target to prevent OA from progression.

Predicting Mortality in African Americans With Type 2 Diabetes Mellitus: Soluble Urokinase Plasminogen Activator Receptor, Coronary Artery Calcium, and High-Sensitivity C-Reactive Protein.

PubMed

Hayek, Salim S; Divers, Jasmin; Raad, Mohamad; Xu, Jianzhao; Bowden, Donald W; Tracy, Melissa; Reiser, Jochen; Freedman, Barry I

2018-05-01

Type 2 diabetes mellitus is a major risk factor for cardiovascular disease; however, outcomes in individual patients vary. Soluble urokinase plasminogen activator receptor (suPAR) is a bone marrow-derived signaling molecule associated with adverse cardiovascular and renal outcomes in many populations. We characterized the determinants of suPAR in African Americans with type 2 diabetes mellitus and assessed whether levels were useful for predicting mortality beyond clinical characteristics, coronary artery calcium (CAC), and high-sensitivity C-reactive protein (hs-CRP). We measured plasma suPAR levels in 500 African Americans with type 2 diabetes mellitus enrolled in the African American-Diabetes Heart Study. We used Kaplan-Meier curves and Cox proportional hazards models adjusting for clinical characteristics, CAC, and hs-CRP to examine the association between suPAR and all-cause mortality. Last, we report the change in C-statistics comparing the additive values of suPAR, hs-CRP, and CAC to clinical models for prediction of mortality. The suPAR levels were independently associated with female sex, smoking, insulin use, decreased kidney function, albuminuria, and CAC. After a median 6.8-year follow-up, a total of 68 deaths (13.6%) were recorded. In a model incorporating suPAR, CAC, and hs-CRP, only suPAR was significantly associated with mortality (hazard ratio 2.66, 95% confidence interval 1.63-4.34). Addition of suPAR to a baseline clinical model significantly improved the C-statistic for all-cause death (Δ0.05, 95% confidence interval 0.01-0.10), whereas addition of CAC or hs-CRP did not. In African Americans with type 2 diabetes mellitus, suPAR was strongly associated with mortality and improved risk discrimination metrics beyond traditional risk factors, CAC and hs-CRP. Studies addressing the clinical usefulness of measuring suPAR concentrations are warranted. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

suPAR level is associated with myocardial impairment assessed with advanced echocardiography in patients with type 1 diabetes with normal ejection fraction and without known heart disease or end-stage renal disease.

PubMed

Theilade, Simone; Rossing, Peter; Eugen-Olsen, Jesper; Jensen, Jan S; Jensen, Magnus T

2016-06-01

Heart disease is a common fatal diabetes-related complication. Early detection of patients at particular risk of heart disease is of prime importance. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker for development of cardiovascular disease. We investigate if suPAR is associated with early myocardial impairment assessed with advanced echocardiographic methods. In an observational study on 318 patients with type 1 diabetes without known heart disease and with normal left ventricular ejection fraction (LVEF) (biplane LVEF >45%), we performed conventional, tissue Doppler and speckle tracking echocardiography, and measured plasma suPAR levels. Associations between myocardial function and suPAR levels were studied in adjusted models including significant covariates. Patients were 55±12 years (mean±s.d.) and 160 (50%) males. Median (interquartile range) suPAR was 3.4 (1.7) ng/mL and LVEF was 58±5%. suPAR levels were not associated with LVEF (P=0.11). In adjusted models, higher suPAR levels were independently associated with both impaired systolic function assessed with global longitudinal strain (GLS) and tissue velocity s', and with impaired diastolic measures a' and e'/a' (all P=0.034). In multivariable analysis including cardiovascular risk factors and both systolic and diastolic measures (GLS and e'/a'), both remained independently associated with suPAR levels (P=0.012). In patients with type 1 diabetes with normal LVEF and without known heart disease, suPAR is associated with early systolic and diastolic myocardial impairment. Our study implies that both suPAR and advanced echocardiography are useful diagnostic tools for identifying patients with diabetes at risk of future clinical heart disease, suited for intensified medical therapy. © 2016 European Society of Endocrinology.

A balance between TFPI and thrombin-mediated platelet activation is required for murine embryonic development

PubMed Central

Ellery, Paul E. R.; Maroney, Susan A.; Cooley, Brian C.; Luyendyk, James P.; Zogg, Mark; Weiler, Hartmut

2015-01-01

Tissue factor pathway inhibitor (TFPI) is a critical anticoagulant protein present in endothelium and platelets. Mice lacking TFPI (Tfpi−/−) die in utero from disseminated intravascular coagulation. They are rescued by concomitant tissue factor (TF) deficiency, demonstrating that TFPI modulates TF function in vivo. Recent studies have found TFPI inhibits prothrombinase activity during the initiation of coagulation and limits platelet accumulation during thrombus formation, implicating TFPI in modulating platelet procoagulant activity. To examine whether altered platelet function would compensate for the lack of TFPI and rescue TFPI-null embryonic lethality, Tfpi+/− mice lacking the platelet thrombin receptor, protease activated receptor 4 (PAR4; Par4−/−), or its coreceptor, PAR3, were mated. PAR3 deficiency did not rescue Tfpi−/− embryos, but >40% of expected Tfpi−/−:Par4−/− offspring survived to adulthood. Adult Tfpi−/−:Par4−/− mice did not exhibit overt thrombosis. However, they had focal sterile inflammation with fibrin(ogen) deposition in the liver and elevated plasma thrombin-antithrombin complexes, indicating activation of coagulation at baseline. Tfpi−/−:Par4−/− mice have platelet and fibrin accumulation similar to Par4−/− mice following venous electrolytic injury but were more susceptible than Par4−/− mice to TF-induced pulmonary embolism. In addition, ∼30% of the Tfpi−/−:Par4−/− mice were born with short tails. Tfpi−/−:Par4−/− mice are the first adult mice described that lack TFPI with unaltered TF. They demonstrate that TFPI physiologically modulates thrombin-dependent platelet activation in a manner that is required for successful embryonic development and identify a role for TFPI in dampening intravascular procoagulant stimuli that lead to thrombin generation, even in the absence of thrombin-mediated platelet activation. PMID:25954015

Protease-activated receptor-4 and purinergic receptor P2Y12 dimerize, co-internalize, and activate Akt signaling via endosomal recruitment of β-arrestin.

PubMed

Smith, Thomas H; Li, Julia G; Dores, Michael R; Trejo, JoAnn

2017-08-18

Vascular inflammation and thrombosis require the concerted actions of several different agonists, many of which act on G protein-coupled receptors (GPCRs). GPCR dimerization is a well-established phenomenon that can alter protomer function. In platelets and other cell types, protease-activated receptor-4 (PAR4) has been shown to dimerize with the purinergic receptor P2Y12 to coordinate β-arrestin-mediated Akt signaling, an important mediator of integrin activation. However, the mechanism by which the PAR4-P2Y12 dimer controls β-arrestin-dependent Akt signaling is not known. We now report that PAR4 and P2Y12 heterodimer internalization is required for β-arrestin recruitment to endosomes and Akt signaling. Using bioluminescence resonance energy transfer, immunofluorescence microscopy, and co-immunoprecipitation in cells expressing receptors exogenously and endogenously, we demonstrate that PAR4 and P2Y12 specifically interact and form dimers expressed at the cell surface. We also found that activation of PAR4 but not of P2Y12 drives internalization of the PAR4-P2Y12 heterodimer. Remarkably, activated PAR4 internalization was required for recruitment of β-arrestin to endocytic vesicles, which was dependent on co-expression of P2Y12. Interestingly, stimulation of the PAR4-P2Y12 heterodimer promotes β-arrestin and Akt co-localization to intracellular vesicles. Moreover, activated PAR4-P2Y12 internalization is required for sustained Akt activation. Thus, internalization of the PAR4-P2Y12 heterodimer is necessary for β-arrestin recruitment to endosomes and Akt signaling and lays the foundation for examining whether blockade of PAR4 internalization reduces integrin and platelet activation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Quercetin Has Antimetastatic Effects on Gastric Cancer Cells via the Interruption of uPA/uPAR Function by Modulating NF-κb, PKC-δ, ERK1/2, and AMPKα.

PubMed

Li, Hai; Chen, Chen

2018-06-01

Gastric cancer (GC) is a malignancy with few effective treatment options after metastasis occurs. Quercetin (Qu) intake has been associated with reduced incidence and slow development of GC, probably due to its anti-proliferative and apoptotic effects, but it is unclear whether Qu can inhibit the metastatic activity. The urokinase plasminogen activator (uPA)/uPA receptor (uPAR) system plays an important role in cancer metastasis. In this study, we measured both uPA activity and uPAR expression in GC and pericarcinous tissues, and we investigated the correlation between uPAR expression and the migratory and invasive activities of various GC cell lines. GC BGC823 and AGS cells were subjected to treatment with 10 μM Qu for 72 hours and uPAR knockdown, alone or in combination, before evaluating cell metastasis. The results showed that uPA activity and uPAR expression were higher in GC tissues than in pericarcinous tissues. Migratory and invasive activities of GC cell lines positively correlated with uPAR expression. Qu treatment decreased BGC823 and AGS cell migration and invasion, accompanied by reduced uPA and uPAR protein expression. Both Qu treatment and uPAR knockdown decreased matrix metalloproteinase-2 and -9 activity and blocked Pak1-Limk1-cofilin signaling. Qu treatment was associated with inhibition of NF-κb, PKC-δ, and ERK1/2, and with AMPKα activation. Specific inhibitors of NF-κb, PKC, and ERK1/2, and an AMPKα activator suppressed uPA and uPAR expression in GC cells. Collectively, Qu showed an antimetastatic effect on GC cells via the interruption of uPA/uPAR function and modulation of NF-κb, PKC-δ, ERK1/2, and AMPKα. This suggests that Qu is a promising agent against GC metastasis.

OVER-EXPRESSION OF THE THROMBIN RECEPTOR (PAR-1) IN THE PLACENTA IN PREECLAMPSIA: A MECHANISM FOR THE INTERSECTION OF COAGULATION AND INFLAMMATION

PubMed Central

EREZ, OFFER; ROMERO, ROBERTO; KIM, SUNG-SU; KIM, JUNG-SUN; KIM, YEON MEE; WILDMAN, DEREK E; THAN, NANDOR GABOR; MAZAKI-TOVI, SHALI; GOTSCH, FRANCESCA; PINELES, BETH; KUSANOVIC, JUAN PEDRO; ESPINOZA, JIMMY; MITTAL, POOJA; MAZOR, MOSHE; HASSAN, SONIA S.; KIM, CHONG JAI

2008-01-01

Objective Preeclampsia (PE) is characterized by excessive thrombin generation that has been implicated in the multiple organ damage associated with the disease. The biological effects of thrombin on coagulation and inflammation are mediated by protease activated receptor-1 (PAR-1), a G-protein coupled receptor. The aim of this study was to determine whether preterm preeclampsia (PE) is associated with changes in placental expression of PAR-1. Study design This cross-sectional study included two groups matched for gestational age at delivery: 1) patients with preterm PE (<37 weeks of gestation; n=26) and 2) a control group of patients with preterm labor without intraamniotic infection (n=26). Placental tissue microarrays were immunostained for PAR-1. Immunoreactivity of PAR-1 in the villous trophoblasts was graded as negative, weak-positive, or strong-positive. Results 1) The proportion of cases with strong PAR-1 immunoreactivity was significantly higher in placentas of patients with preeclampsia than in placentas from the control group [37.5% (9/24) vs. 8.7% (2/23); p=0.036, respectively]. 2) PAR-1 immunoreactivity was found in the cellular compartments of the placental villous tree, mainly in villous trophoblasts and stromal endothelial cells. 3) PAR-1 was detected in 92.3% (24/26) of the placentas of women with preeclampsia and in 88.5% (23/26) of the placentas from the control group (p=1). Conclusion Placentas from pregnancies complicated by preterm PE had a significantly higher frequency of strong PAR-1 expression than placentas from women with spontaneous PTL. This observation is consistent with a role for PAR-1 as a mediator of the effect of thrombin on coagulation and inflammation in preeclampsia. We propose that the effects of thrombin in PE are due to increased thrombin generation and higher expression of PAR-1, the major receptor for this enzyme. PMID:18570113

PET imaging of urokinase-type plasminogen activator receptor (uPAR) in prostate cancer: current status and future perspectives.

PubMed

Skovgaard, Dorthe; Persson, Morten; Kjaer, Andreas

2016-01-01

Overexpression of urokinase-type plasminogen activator receptors (uPAR) represents an important biomarker for aggressiveness in most common malignant diseases, including prostate cancer (PC). Accordingly, uPAR expression either assessed directly in malignant PC tissue or assessed directly in plasma (intact/cleaved forms)-provides independent additional clinical information to that contributed by PSA, Gleason score, and other relevant pathological and clinical parameters. In this respect, non-invasive molecular imaging by positron emission tomography (PET) offers a very attractive technology platform, which can provide the required quantitative information on the uPAR expression profile, without the need for invasive procedures and the risk of missing the target due to tumor heterogeneity. These observations support non-invasive PET imaging of uPAR in PC as a clinically relevant diagnostic and prognostic imaging method. In this review, we will focus on the recent development of uPAR PET and the relevance within prostate cancer imaging. Novel antibody and small-molecule radiotracers-targeting uPAR, including a series of uPAR-targeting PET ligands, based on the high affinity peptide ligand AE105, have been synthesized and tested in vitro and in vivo in preclinical murine xenograft models and, recently, in a first-ever clinical uPAR PET study in cancer patients, including patients with PC. In this phase I study, a high and specific uptake of the tracer 64 Cu-DOTA-AE105 was found in both primary tumors and lymph node metastases. The results are encouraging and support large-scale clinical trials to determine the utility of uPAR PET in the management of patients with PC with the goal of improving outcome.

Regulation of feto-maternal barrier by matriptase- and PAR-2-mediated signaling is required for placental morphogenesis and mouse embryonic survival.

PubMed

Szabo, Roman; Peters, Diane E; Kosa, Peter; Camerer, Eric; Bugge, Thomas H

2014-07-01

The development of eutherian mammalian embryos is critically dependent on the selective bi-directional transport of molecules across the placenta. Here, we uncover two independent and partially redundant protease signaling pathways that include the membrane-anchored serine proteases, matriptase and prostasin, and the G protein-coupled receptor PAR-2 that mediate the establishment of a functional feto-maternal barrier. Mice with a combined matriptase and PAR-2 deficiency do not survive to term and the survival of matriptase-deficient mice heterozygous for PAR-2 is severely diminished. Embryos with the combined loss of PAR-2 and matriptase or PAR-2 and the matriptase partner protease, prostasin, uniformly die on or before embryonic day 14.5. Despite the extensive co-localization of matriptase, prostasin, and PAR-2 in embryonic epithelia, the overall macroscopic and histological analysis of the double-deficient embryos did not reveal any obvious developmental abnormalities. In agreement with this, the conditional deletion of matriptase from the embryo proper did not affect the prenatal development or survival of PAR-2-deficient mice, indicating that the critical redundant functions of matriptase/prostasin and PAR-2 are limited to extraembryonic tissues. Indeed, placentas of the double-deficient animals showed decreased vascularization, and the ability of placental epithelium to establish a functional feto-maternal barrier was severely diminished. Interestingly, molecular analysis suggested that the barrier defect was associated with a selective deficiency in the expression of the tight junction protein, claudin-1. Our results reveal unexpected complementary roles of matriptase-prostasin- and PAR-2-dependent proteolytic signaling in the establishment of placental epithelial barrier function and overall embryonic survival.

Étude comparative des techniques d'analyse par fluorescence X à dispersion d'énergie (ED-XRF) et à dispersion de longueur d'onde (WD-XRF), et par spectrométrie d'émission atomique à source plasma couplée par induction (ICP-AES)

NASA Astrophysics Data System (ADS)

Rahmani, A.; Benyaïch, F.; Bounakhla, M.; Bilal, E.; Moutte, J.; Gruffat, J. J.; Zahry, F.

2004-11-01

Dans ce travail, nous présentons une étude comparative des techniques d'analyse par fluorescence X à dispersion d'énergie (ED-XRF) et à dispersion de longueur d'onde (WD-XRF), et par spectrométrie d'émission atomique à source plasma couplée par induction (ICP-AES). Les résultats de la calibration des spectromètres à dispersion d'énergie, à excitation par sources radioactives (55Fe, 109Cd et 241Am) et à excitation secondaire (cible secondaire Mo et Cu) du Centre National pour l'Energie, les Sciences et les Techniques Nucléaires (CNESTEN, Rabat, Maroc) sur des échantillons étalons de références de l'Agence International de l'Energie Atomique (AIEA) et du Community Bureau of Référence (BCR) ont été comparés aux résultats d'analyse des mêmes échantillons étalons par la spectrométrie X à dispersion de longueur d'onde (WD-XRF) et par spectrométrie d'émission atomique à source plasma couplé par induction (ICP-AES) au département GENERIC du centre SPIN à l'Ecole des Mines de Saint-Etienne (France). Les trois techniques d'analyse utilisées donnent des résultats comparables pour le dosage des éléments majeurs, alors que pour les traces on note des déviations importantes à cause des effets de matrice qui sont difficiles à corriger dans le cas de la fluorescence X.

NaCl-induced physiological and biochemical changes in two cyanobacteria Nostoc muscorum and Phormidium foveolarum acclimatized to different photosynthetically active radiation.

PubMed

Kumar, Jitendra; Singh, Vijay Pratap; Prasad, Sheo Mohan

2015-10-01

The present study is aimed at investigating physiological and biochemical behavior of two cyanobacteria Nostoc muscorum and Phormidium foveolarum acclimatized to different levels (sub-optimum; 25 ± 0.5, optimum; 75 ± 2.5 and supra-optimum; 225 ± 3.5 μmol photons m(-2) s(-1)) of photosynthetic active radiation (PAR), and subsequently treated with two doses (30 and 90 mM) of NaCl. PAR influences growth in tested cyanobacteria being maximum in supra-optimum PAR acclimatized cells. NaCl-induced maximum percent decline in growth was observed in sub-optimum PAR acclimatized cells, which was in consonance with a decrease in chlorophyll content. Sub-optimum PAR acclimatization stimulated phycocyanin content in control cells, whereas maximum carotenoids content was observed in supra-optimum PAR acclimatized cells. Photosystem II photochemistry viz. Fv/F0, Fv/Fm, Ψ0, ϕE0, PIABS, ABS/RC, TR0/RC, ET0/RC and DI0/RC was also influenced by PAR and NaCl. Maximum percent rise in superoxide radical (SOR), hydrogen peroxide (H2O2) and lipid peroxidation was observed in sub-optimum PAR acclimatized cells exposed to NaCl, which could be correlated with lower values of enzymatic (superoxide dismutase, catalase, peroxidase and glutathione-S-transferase) and non-enzymatic (NP-SH and cysteine) antioxidants. In supra-optimum PAR acclimatized cells level of oxidative stress markers was in parallel with enhanced antioxidants. The results suggest that PAR significantly changes physiological and biochemical responses of studied cyanobacteria under NaCl stress. Besides this, this study also shows that P. foveolarum is more tolerant than N. muscorum under test conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Looping and clustering model for the organization of protein-DNA complexes on the bacterial genome

NASA Astrophysics Data System (ADS)

Walter, Jean-Charles; Walliser, Nils-Ole; David, Gabriel; Dorignac, Jérôme; Geniet, Frédéric; Palmeri, John; Parmeggiani, Andrea; Wingreen, Ned S.; Broedersz, Chase P.

2018-03-01

The bacterial genome is organized by a variety of associated proteins inside a structure called the nucleoid. These proteins can form complexes on DNA that play a central role in various biological processes, including chromosome segregation. A prominent example is the large ParB-DNA complex, which forms an essential component of the segregation machinery in many bacteria. ChIP-Seq experiments show that ParB proteins localize around centromere-like parS sites on the DNA to which ParB binds specifically, and spreads from there over large sections of the chromosome. Recent theoretical and experimental studies suggest that DNA-bound ParB proteins can interact with each other to condense into a coherent 3D complex on the DNA. However, the structural organization of this protein-DNA complex remains unclear, and a predictive quantitative theory for the distribution of ParB proteins on DNA is lacking. Here, we propose the looping and clustering model, which employs a statistical physics approach to describe protein-DNA complexes. The looping and clustering model accounts for the extrusion of DNA loops from a cluster of interacting DNA-bound proteins that is organized around a single high-affinity binding site. Conceptually, the structure of the protein-DNA complex is determined by a competition between attractive protein interactions and loop closure entropy of this protein-DNA cluster on the one hand, and the positional entropy for placing loops within the cluster on the other. Indeed, we show that the protein interaction strength determines the ‘tightness’ of the loopy protein-DNA complex. Thus, our model provides a theoretical framework for quantitatively computing the binding profiles of ParB-like proteins around a cognate (parS) binding site.