Components Of Beta Research Articles

Airway smooth muscle prostaglandin-EP1 receptors directly modulate 2-adrenergic receptors within a unique heterodimeric complex

Multiple and paradoxical effects of airway smooth muscle (ASM) 7-transmembrane-spanning receptors activated during asthma, or by treatment with bronchodilators such as beta(2)-adrenergic receptor (beta(2)AR) agonists, indicate extensive receptor crosstalk. We examined the signaling of the prostanoid-EP(1) receptor, since its endogenous agonist prostaglandin E(2) is abundant in the airway, but its functional implications are poorly defined. Activation of EP(1) failed to elicit ASM contraction in mouse trachea via this G(alphaq)-coupled receptor. However, EP(1) activation markedly reduced the bronchodilatory function of beta(2)AR agonist, but not forskolin, indicating an early pathway interaction. Activation of EP(1) reduced beta(2)AR-stimulated cAMP in ASM but did not promote or augment beta(2)AR phosphorylation or alter beta(2)AR trafficking. Bioluminescence resonant energy transfer showed EP(1) and beta(2)AR formed heterodimers, which were further modified by EP(1) agonist. In cell membrane [(35)S]GTPgammaS binding studies, the presence of the EP(1) component of the dimer uncoupled beta(2)AR from G(alphas), an effect accentuated by EP(1) agonist activation. Thus alone, EP(1) does not appear to have a significant direct effect on airway tone but acts as a modulator of the beta(2)AR, altering G(alphas) coupling via steric interactions imposed by the EP(1):beta(2)AR heterodimeric signaling complex and ultimately affecting beta(2)AR-mediated bronchial relaxation. This mechanism may contribute to beta-agonist resistance found in asthma.

Identifikasi dan Klasifikasi Sinyal EEG terhadap Rangsangan Suara dengan Ekstraksi Wavelet dan Spektral Daya

In this research the development of identification and classification technique of three wave components of EEG signal, named alpha, beta and theta, is considered. The technique is combination of wavelet transform and power spectral analysis. Wavelet transform was used to extract the wave components so it reduces the data without loss of the information. The wavelet transform also reduces the aspects of non-stationary of the EEG signal. The EEG's wave classification was based on the appearance of the wave, synchronization between symmetric hemispheres, and the wave energy

Boundary-element calculations for dielectric behavior of doublet-shaped cells

In order to simulate dielectric relaxation spectra (DRS) of budding yeast cells (Saccharomyces cerevisiae) in suspension, the complex polarization factor (Clausius-Mossotti factor) beta for a single cell and the complex permittivity of a cell suspension epsilon(sus)* were calculated with a doublet-shaped model (model RD), in which two spheres were connected with a part of a ring torus, using the boundary element method. The beta values were represented by a diagonal tensor consisting of components beta(z) parallel to the rotation axis (z axis) and beta(h) in a plane (h plane) perpendicular to the axis. The epsilon(sus)* values were calculated from the complex permittivity of the suspending medium epsilon(a)* and the components of beta. The calculation was compared with that of a conventional prolate spheroid model (model CP). It was found that model CP could be used as a first approximation to model RD. However, differences existed in beta(z) between models RD and CP; beta(z) showed three relaxation terms in the case of model RD in contrast with two terms in model CP. Narrowing the junction between the two spheres in model RD markedly decreased the characteristic frequency of one of the relaxation terms in beta(z). This suggests that the structure of the junction can be estimated from DRS. Effects of the shape change from model RD to a two-sphere model (model RD without the junction) were also examined. The behavior of beta(z) in the two-sphere model, the relaxation intensity of which was much lower than model RD, was quite similar to that in a single-sphere model. These simulations were consistent with the experimental observations of the dielectric behavior of the yeast cells during cell cycle progression.

Logistic regression of family data from retrospective study designs.

We wish to study the effects of genetic and environmental factors on disease risk, using data from families ascertained because they contain multiple cases of the disease. To do so, we must account for the way participants were ascertained, and for within-family correlations in both disease occurrences and covariates. We model the joint probability distribution of the covariates of ascertained family members, given family disease occurrence and pedigree structure. We describe two such covariate models: the random effects model and the marginal model. Both models assume a logistic form for the distribution of one person's covariates that involves a vector beta of regression parameters. The components of beta in the two models have different interpretations, and they differ in magnitude when the covariates are correlated within families. We describe ascertainment assumptions needed to estimate consistently the parameters beta(RE) in the random effects model and the parameters beta(M) in the marginal model. Under the ascertainment assumptions for the random effects model, we show that conditional logistic regression (CLR) of matched family data gives a consistent estimate beta(RE) for beta(RE) and a consistent estimate for the covariance matrix of beta(RE). Under the ascertainment assumptions for the marginal model, we show that unconditional logistic regression (ULR) gives a consistent estimate for beta(M), and we give a consistent estimator for its covariance matrix. The random effects/CLR approach is simple to use and to interpret, but it can use data only from families containing both affected and unaffected members. The marginal/ULR approach uses data from all individuals, but its variance estimates require special computations. A C program to compute these variance estimates is available at http://www.stanford.edu/dept/HRP/epidemiology. We illustrate these pros and cons by application to data on the effects of parity on ovarian cancer risk in mother/daughter pairs, and use simulations to study the performance of the estimates.

Analyzing Spatial Structure of Communities Using the Two‐Dimensional Poisson Lognormal Species Abundance Model

The joint spatial and temporal fluctuations in the community structure of tropical butterflies are analyzed by fitting the bivariate Poisson lognormal distribution to a large number of observations in space and time. By applying multivariate dependent diffusions for describing the fluctuations in the abundances, the environmental variance is estimated to be very large and so is the strength of local density regulation. The variance in the lognormal species abundance distribution is partitioned into components expressing the heterogeneity between the species, independent noise components for the different species, a demographic stochastic component, and a component due to overdispersion in the sampling. In disagreement with the neutral theory, the estimates show that the heterogeneity component is the dominating one, representing 81% of the total variance in the lognormal model. Different spatial components of diversity, the alpha, beta, and gamma diversity, are also estimated. The spatial scale of the autocorrelation function for the community is of order 1 km, while sampling of a quadrat would need to be 10 km on a side to yield the total diversity for the community.

Distorted DNA structures induced by HMGB2 possess a high affinity for HMGB2.

HMGB2 (HMG2) protein binds with DNA duplex in a sequence-nonspecific manner, then bends and unwinds the DNA. In DNA cyclization analyses for the bending activity of HMGB2, two unidentified bands, denoted alpha and beta, were observed in addition to monomer circular DNA (1C) on the gel. Re-electrophoresis and proteinase K digestion revealed that alpha and beta are complexes of circularized probe DNA (seeming 1C) with HMGB2 (K(d) approximately 10(-10) M). The DNA components of alpha and beta (alpha- and beta-DNA) showed higher affinities to HMGB2 than did the linear probe DNA (K(d) approximately 10(-7) M). The DNAs have distorted structures containing partial single-stranded regions. Nicked circular molecules presumably due to severe DNA distortion by HMGB2 were observed in alpha- and beta-DNA, in addition to closed circular double-stranded molecules. The alpha and beta bands were not formed in the presence of sole DNA binding regions which are necessary for DNA bending, indicating that the acidic C-tail in the HMGB2 molecule is necessary for inducing the peculiar distorted structures of higher affinity to HMGB2. HMGB2 binds with linker DNA and/or the entry and exit of nucleosomes fixed at both ends likewise mini-circles similar to alpha-DNA and beta-DNA. Thus, the distorted structures present in alpha-DNA and beta-DNA should be important in considering the functional mechanisms in which HMGB2 participates.

Analyzing Spatial Structure of Communities Using the Two-Dimensional Poisson Lognormal Species Abundance Model

The joint spatial and temporal fluctuations in the community structure of tropical butterflies are analyzed by fitting the bivariate Poisson lognormal distribution to a large number of observations in space and time. By applying multivariate dependent diffusions for describing the fluctuations in the abundances, the environmental variance is estimated to be very large and so is the strength of local density regulation. The variance in the lognormal species abundance distribution is partitioned into components expressing the heterogeneity between the species, independent noise components for the different species, a demographic stochastic component, and a component due to overdispersion in the sampling. In disagreement with the neutral theory, the estimates show that the heterogeneity component is the dominating one, representing 81% of the total variance in the lognormal model. Different spatial components of diversity, the alpha, beta, and gamma diversity, are also estimated. The spatial scale of the autocorrelation function for the community is of order 1 km, while sampling of a quadrat would need to be 10 km on a side to yield the total diversity for the community.

Characterization of a lipopeptide-resistant strain ofCandida albicans

Lipopeptides are antifungal agents that inhibit cell wall beta-(1,3)-glucan biosynthesis in fungal organisms. A mutant resistant to lipopeptides was generated by UV mutagenesis and characterized. The Candida albicans mutant (LP3-1) was stable and showed resistance specificity to a broad range of lipopeptides and certain glycolipid inhibitors. Other antifungal agents with diverse modes of action had a normal minimum inhibitory concentration profile for LP3-1 compared with the wild-type strain (CCH 442). In the in vitro beta-(1,3)-glucan synthase assay, both the lipopeptides and papulacandin-related agents had considerably higher 50% inhibitory concentration values in the LP3-1 strain than in the wild-type strain. In reconstitution assays, the resistance factor was associated with the integral membrane pellet rather than the peripheral GTP-binding protein. The LP3-1 strain had a membrane lipid profile similar to that of the parent strain and was virulent in a murine model of systemic candidiasis. Taken together, these results indicate that the resistance factor is associated with the integral membrane component of beta-(1,3)-glucan synthase. Lipopeptides are common antifungal agents encountered during screening of natural products. The LP3-1 strain was resistant to natural product extracts known to contain various lipopeptides. Thus, LP3-1 can be used in a dereplication assay.

Diversity, disturbance, and sustainable use of Neotropical forests: insects as indicators for conservation monitoring

Sustainable use of tropical forest systems requires continuous monitoring of biological diversity and ecosystem functions. This can be efficiently done with ‘early warning‘ (short-cycle) indicator groups of non-economical insects, whose population levels and resources are readily measured. Twenty-one groups of insects are evaluated as focal indicator taxa for rapid assessment of changes in Neotropical forest systems. Composite environmental indices for heterogeneity, richness, and natural disturbance are correlated positively with butterfly diversity in 56 Neotropical sites studied over many years. Various components of alpha, beta and gamma-diversity show typical responses to increased disturbance and different land-use regimes. Diversity often increases with disturbance near or below natural levels, but some sensitive species and genes are eliminated at very low levels of interference. Agricultural and silvicultural mosaics with over 30% conversion, including selective logging of three or more large trees per hectare, show shifts in species composition with irreversible loss of many components of the butterfly community, indicating non-sustainable land and resource use and reduction of future options. Monitoring of several insect indicator groups by local residents in a species-rich Brazilian Amazon extractive reserve has helped suggest guidelines for cologically, economically, and socially sustainable zoning and use regimes.

Eosinophils: from low- to high-affinity immunoglobulin E receptors.

Several experimental approaches have been used to identify immunoglobulin (IgE) binding molecules expressed by human eosinophils. After the description that Fc epsilon RII/CD23 identified on eosinophils could participate in IgE binding and IgE-mediated cytotoxicity, Mac2/epsilon binding proteins belonging to the S-type lectin family were also detected on human eosinophils. Anti-Mac2 monoclonal antibodies inhibited eosinophil-dependent cytotoxicity towards parasitic targets. More recently, Fc epsilon RI was demonstrated on human eosinophils from hypereosinophilic patients. The 3 components of Fc epsilon RI, alpha, beta and gamma chains, were detected in eosinophils. The alpha chain of Fc epsilon RI was shown to be involved in IgE binding to eosinophils and in the selective release of eosinophil peroxidase. The participation of Fc epsilon RI-bearing eosinophils in a protective immune response against a parasitic infection indicates a so far unsuspected function of Fc epsilon RI. The interactions between the different types of IgE binding molecules are discussed.

Time component of the mirror beta decays of12B and12N

Beta-ray angular distributions from aligned12B and12N have been observed in order to study the meson-exchange effect in a nucleus. Alignment-correlation coefficients α∓ for12B and12N were determined to be α−=−(0.0174±0.0059)%/MeV and α+=−(0.2774±0.0086)%/MeV, respectively. These values are fairly consistent with the previous values, while the reliability was greatly improved. From these coefficients, the nuclear parametery, i.e. the ratio of the time component of the axial vector currents of the Gamow-Teller matrix element, was determined to bey=4.13±0.15. The value is enhanced by 33% from that calculated by use of the impulse approximation, which clearly shows a considerable effect due to meson-exchange currents.

New photochromic and electro-optically active derivatives of TCNQ: calculated SHG parameters of model zwitterionic and quinonoidal structures

The calculated values of the vector average of beta (-2 omega , omega , omega ), beta -vec, for two pyridinium alpha -cyano-4-styryldicyanomethanides, are shown to be dominated by a diagonal contribution from the first excited (intramolecular charge transfer) electronic state. However, there are non-negligible off-diagonal contributions from an interaction between the first and third excited electronic states. In all cases, by far the most dominant component of beta -vec is beta xxx. The values of beta X and beta xxx for the zwitterionic and quinonoidal forms of both the 2-pyridinium and 4-pyridinium compounds are large and negative in the pre-resonant region due to the fact that the intramolecular charge-transfer transition is accompanied by a large and negative change in molecular electric dipole moment in the x (long-axis) direction.

Purification and properties of epithelial growth inhibitor (EGI) from human platelets: its separation from type beta transforming growth factor (TGF-beta).

We previously reported that sera from various kinds of animals contain a protein(s) capable of inhibiting the growth of the non-malignant epithelial cell line derived from Buffalo rat liver (BRL). In the present study, a similar epithelial cell-specific growth inhibitor (EGI) was purified to homogeneity from an acid-ethanol extract of human platelets. During purification, EGI was separated from the major component of type beta transforming growth factor (TGF-beta), which can stimulate the colony formation of the non-malignant fibroblastic cell line derived from rat kidney (NRK) in soft agar in the presence of epidermal growth factor (EGF). The purified EGI had an Mr of 27,000, and was composed of two subunits identical in Mr. It significantly inhibited the growth in monolayer cultures of three non-malignant epithelial cell lines, BRL, MDCK (from Madin-Darby canine kidney) and BSC-1 (from African green monkey kidney), at doses lower than 40 pg/ml in medium containing 10% fetal calf serum. Its inhibitory activity was stable against heating at 90 degrees C for 3 min, but not against treatment with 50 mM dithiothreitol. In addition, TGF-beta was also partially purified from the same extract. The purified TGF-beta did not show any inhibitory activity toward the growth of BRL, MDCK, BSC-1, or NRK.

Weighted averages and order parameters for the infinite range Ising spin glass

The Sherrington-Kirkpatrick spin glass model (1975) is studied by replicas and by analysing the mean field equations of Thouless, Anderson and Palmer (TAP) (1977). The authors show that the standard order parameter defined by statistical mechanics is given by the average of all off-diagonal components of the matrix qalpha beta . There is consequently no violation of the fluctuation dissipation theorem. They describe how to weight the different solutions of the TAP equations and argue that there is no entropy from solution degeneracy. This assumption is shown to be internally consistent. The square of a spin expectation value for a solution, averaged over solutions, is shown to be q(1) if they make the Parisi-Sompolinsky ansatz for qalpha beta .

Two Rapid and Improved Techniques for Chromatographic Fractionation of Casein

The major components of casein, alphas-, beta-, kappa-, and gamma-caseins, were chromatographically fractionated on diethylaminoethyl ion-exchange cellulose in stepwise elution with pH 8, .03M glycine, or pH 7, .005M phosphate buffers in the presence of 3.3M urea and .1% 2-mercaptoethanol. Fractionation was at room temperature (around 25C) in 4 to 4.5h. The components showed a reasonable purity electrophoretically. These techniques can be used for quantitative estimation of casein composition.

Hyaluronic acid: a required component of beta hemolytic streptococci for infecting mice by aerosol.

Hyaluronic acid: a required component of beta hemolytic streptococci for infecting mice by aerosol.