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1.
JP O'Bryan Z Songyang L Cantley CJ Der T Pawson 《Canadian Metallurgical Quarterly》1996,93(7):2729-2734
The Shc adaptor protein, hereafter referred to as ShcA, possesses two distinct phosphotyrosine-recognition modules, a C-terminal Src homology 2 (SH2) domain and an N-terminal phosphotyrosine-binding (PTB) domain, and is itself phosphorylated on tyrosine in response to many extracellular signals. Phosphorylation of human ShcA at Tyr-317 within its central (CH1) region induces binding to the Grb2 SH2 domain and is thereby implicated in activation of the Ras pathway. Two shc-related genes (shcB and shcC) have been identified in the mouse. shcB is closely related to human SCK, while shcC has not yet been found in other organisms. The ShcC protein is predicted to have a C-terminal SH2 domain, a CH1 region with a putative Grb2-binding site, and an N-terminal PTB domain. The ShcC and ShcB SH2 domains bind phosphotyrosine-containing peptides and receptors with a specificity related to, but distinct from, that of the ShcA SH2 domain. The ShcC PTB domain specifically associates in vitro with the autophosphorylated receptors for nerve growth factor and epidermal growth factor. These results indicate that ShcC has functional SH2 and PTB; domains. In contrast to shcA, which is widely expressed, shcC RNA and proteins are predominantly expressed in the adult brain. These results suggest that ShcC may mediate signaling from tyrosine kinases in the nervous system, such as receptors for neurotrophins. 相似文献
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Zoe R. Howard Corliss A. O'Bryan Philip G. Crandall Steven C. Ricke 《Food research international (Ottawa, Ont.)》2012,45(2):755-764
Foodborne illness caused by Salmonella spp. is a worldwide problem. In the United States Salmonella Enteritidis is the second most commonly isolated serotype from human illness, and is known to be strongly associated with shell eggs and egg containing products. Eggs can become contaminated internally either by penetration through the shell or directly during formation in the reproductive tract. This review begins with a brief account of the physiology of egg production and the various physical and chemical barriers the egg possesses to prevent bacterial contamination. Factors involved in vertical and horizontal transmission of S. Enteritidis are examined, as well as the role of forced molt in colonization of the hen. Pre- and post-harvest mitigation strategies are also discussed. 相似文献
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Henry M. O'Bryan Patrick K. Gallagher G.W. Berkstresser 《Journal of the American Ceramic Society》1988,71(1):42-C-
The thermal expansion of Y2 SiO5 crystals has been measured for the principal crystallographic directions and two orthogonal directions in the (010) plane in the temperature range 25° to 200°C. This monoclinic crystal has strongly anisotropic expansions with coefficients which range from 0.6 × 10−6 /°C for [100] to 11.4 × 10−6 /°C for [001]. Third-order polynomials have been calculated from the expansion curves. Data for the β angle and cell volume as a function of temperature are also given. The thermal expansion of Y2 SiO5 crystals is not affected by doping with 5% Tb. 相似文献
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The defect model of Abrahams and Marsh is expanded to consider the addition of TiO2 and other oxides to form solid solutions with both the stoichiometric and congruent compositions of LiNbO3 . It is shown that the Curie temperature (Tc ) and the limits of solubility are determined by the cation vacancy content regardless of whether these are formed by Li deficiency or the addition or substitution of aliovalent ions. X-ray powder diffraction patterns indicate that the a-axis parameter decreases markedly with additions of TiO2 while the c-axis parameter remains essentially unchanged. These results are compared with prior investigations, and the technological implications of this work to lightguide devices are described. 相似文献
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ABSTRACT: Seven citrus essential oils (EOs) were screened by disc diffusion assay for their antibacterial activity against 11 serotypes/strains of Salmonella . The 3 most active oils were selected to determine the minimal inhibitory concentration (MIC) against the same Salmonella . Orange terpenes, single-folded d-limonene, and orange essence terpenes all exhibited inhibitory activity against the Salmonella spp. on the disc diffusion assay. EOs were stabilized in broth by the addition of 0.15% (w/v) agar for performance of the MIC tests. Orange terpenes and d-limonene both had MICs of 1%. The most active compound, terpenes from orange essence, produced an MIC that ranged from 0.125% to 0.5% against the 11 Salmonella tested. Gas chromatography-mass spectrometry (GC/MS) analysis revealed that this orange essence oil was composed principally of d-limonene, 94%, and myrcene at about 3%. EOs from citrus offer the potential for all natural antimicrobials for use in improving the safety of organic or all natural foods. 相似文献
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E.C. Friedly P.G. Crandall S.C. Ricke M. Roman C. O'Bryan V.I. Chalova 《Journal of food science》2009,74(2):M67-M72
ABSTRACT: The objectives of this study were to screen activity of citrus essential oil fractions (EOs) alone and in combination with organic acids against 2 species of Listeria . Five citrus EOs were initially screened by disc diffusion assay for antibacterial activity. Cold pressed terpeneless Valencia orange oil (CP terpeneless oil) had the strongest bacteriostatic (MIC) and bactericidal (MBC) properties at 0.55% and 1.67%, respectively. Four organic acids were tested for effectiveness against Listeria . Citric and malic acids proved to be the most effective with MBC of 1.1% alone. Assays were conducted to determine synergistic effects of EOs and citric or malic acids. There was a significant decrease in MIC and MBC to 0.04% EO plus 0.12% malic or citric acid. EOs from citrus paired with organic acids offer the potential as an all-natural antimicrobial for improving the safety of all-natural foods. 相似文献
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It has recently been shown that electronic transport in zigzag graphene nanoribbons becomes spin-polarized upon application of an electric field across the nanoribbon width. However, the electric fields required to experimentally induce this magnetic state are typically large and difficult to apply in practice. Here, using both first-principles density functional theory (DFT) and time-dependent DFT, we show that a new spiropyran-based, mechanochromic polymer noncovalently deposited on a nanoribbon can collectively function as a dual opto-mechanical switch for modulating its own spin-polarization. These calculations demonstrate that upon mechanical stress or photoabsorption, the spiropyran chromophore isomerizes from a closed-configuration ground-state to a zwitterionic excited-state, resulting in a large change in dipole moment that alters the electrostatic environment of the nanoribbon. We show that the electronic spin-distribution in the nanoribbon-spiropyran hybrid material can be reversibly modulated via noninvasive optical and mechanical stimuli without the need for large external electric fields. Our results suggest that the reversible spintronic properties inherent to the nanoribbon-spiropyran material allow the possibility of using this hybrid structure as a resettable, molecular-logic quantum sensor where opto-mechanical stimuli are used as inputs and the spin-polarized current induced in the nanoribbon substrate is the measured output. 相似文献
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Jarvis N Clement AR O'Bryan CA Babu D Crandall PG Owens CM Meullenet JF Ricke SC 《Journal of food science》2012,77(6):S253-S257
In order to address the growing demand for more natural poultry products, alkaline phosphates commonly used in chicken breast meat marinades were replaced with plum ingredients and evaluated. For initial sensory evaluation, 200 consumers of chicken were served a small portion of the chicken breast on a plate and were asked to evaluate the product for overall impression, flavor, and texture on a 9-point hedonic scale with 1 = "dislike extremely" and 9 = "like extremely." Also, a 5-point just-about-right (JAR) scale was used on questions about tenderness, juiciness, overall flavor, and saltiness. Both hedonic and JAR demonstrated that the marinades of plum concentrate and the blend of plum fiber and powder were not distinguishable from the control (P > 0.05). Using two different percentages of fiber/powder blend, two different percentages of concentrate, sodium tripolyphosphate (STPP), and no marinade, measurements were made for marinade per cent pickup, thaw loss, and cook loss. Plum concentrate at 1.1% was most similar to STPP in marinade per cent pickup, thaw loss, drip loss, and cook loss. These results show that plum ingredients can potentially be used as a substitute in standard phosphate marinades. PRACTICAL APPLICATION: Consumers are increasingly demanding more natural foods with less artificial additives. This research presents the results of experiments using dried plum ingredients as a substitute for phosphates commonly used in marinades for chicken. Results indicate that dried plum ingredients may be a suitable substitute for phosphates in marinades. 相似文献