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排序方式: 共有1301条查询结果,搜索用时 15 毫秒
71.
Tenuazonic acid (TA) is a major water soluble Alternaria mycotoxin. In the present work, a method for the quantification of TA in beer by liquid chromatography–ion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine is described. The method is based on a rapid workup procedure and features a LOD of 2 μg/kg without preconcentration using 400 mg of sample. Validation was performed for a working range of 8–500 μg/kg. 相似文献
72.
73.
Diana Brumini Camilla Bø Furlund Irene Comi Tove Gulbrandsen Devold Donata Marletta Gerd E. Vegarud Christine Monceyron Jonassen 《International Dairy Journal》2013,28(2):109-111
Antiviral activity of Ragusano donkeys' milk proteins was investigated for the effect on echovirus type 5, known to infect the gastrointestinal tract of humans. Three protein fractions were tested; casein (CN), whey protein (WP) and a low molecular whey protein fraction (LWP; <30,000 Da). The antiviral activity of WP and LWP was tested on echovirus type 5 at three concentrations (1, 5 and 10 mg mL?1); CN was assessed only at the lower concentration. All donkey milk protein fractions showed significant inhibition on virus replication at the concentration of 1 mg mL?1, and both WP and LWP fractions showed significant inhibition on the virus replication at all concentrations tested. The strongest antiviral effect was observed for the WP fraction. These findings show that the different whey proteins in donkey milk, probably acting in synergy, exert antiviral activity on echovirus 5 and might contribute to prevent gastrointestinal virus infections in humans. 相似文献
74.
Lee Christine M.; Geisner Irene M.; Patrick Megan E.; Neighbors Clayton 《Canadian Metallurgical Quarterly》2010,24(2):342
Social norms for alcohol use are important influences on individual college student drinking. The present study extends social norms research by examining alcohol-related consequences and, in particular, whether similar misperceptions exist regarding the frequency and evaluation of these consequences over time. College student drinkers (N = 624) participating in a longitudinal study completed Web-based surveys assessing alcohol use and related consequences, as well as their beliefs about frequency and evaluation of consequences for the typical college student. Findings suggest that students overestimated how often typical college students experience negative consequences and underestimated how negatively other students evaluated those consequences. Finally, results support a bidirectional model for alcohol-related consequences, possibly indicating a reciprocal, mutually influential feed-forward loop of norms and consequences that promotes maintenance of college student drinking and consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
75.
Irene Papanayotou Beimeng Sun Amy F. Roth Nicholas G. Davis 《Yeast (Chichester, England)》2010,27(10):801-816
Yeast cell lysates produced by mechanical glass bead disruption are widely used in a variety of applications, including for the analysis of native function, e.g. protein–protein interaction, enzyme assays and membrane fractionations. Below, we report a striking case of protein denaturation and aggregation that is induced by this lysis protocol. Most of this analysis focuses on the type 1 casein kinase Yck2, which normally tethers to the plasma membrane through C‐terminal palmitoylation. Surprisingly, when cells are subjected to glass bead disruption, non‐palmitoylated, cytosolic forms of the kinase denature and aggregate, while membrane‐associated forms, whether attached through their native palmitoyl tethers or through a variety of artificial membrane‐tethering sequences, are wholly protected from denaturation and aggregation. A wider look at the yeast proteome finds that, while the majority of proteins resist glass bead‐induced aggregation, a significant subset does, in fact, succumb to such denaturation. Thus, yeast researchers should be aware of this potential artifact when embarking on biochemical analyses that employ glass bead lysates to look at native protein function. Finally, we demonstrate an experimental utility for glass bead‐induced aggregation, using its fine discrimination of membrane‐associated from non‐associated Yck2 forms to discern fractional palmitoylation states of Yck2 mutants that are partially defective for palmitoylation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
76.
Rajendra P. Maskey Ines Kock Mohamed Shaaban Iris Grün-Wollny Elisabeth Helmke Frank Mayer Irene Wagner-Döbler Hartmut Laatsch 《Polymer Bulletin》2002,49(2-3):87-93
Summary
A new group of low-molecular weight channel-forming oligo(hydroxybutyric acids) (cPHBs, 1 with n = 8–30; main component MW ≈ 1300 dalton) was isolated from microorganisms of different origin. Inclusion bodies were
electron-microscopically visible in cells in the state of autolysis, not in cells in the exponential phase of growth. cPHB
and high-molecular poly(l3-hydroxybutyric acid) (sPHB) is cleaved by phenylethylamine and forms the corresponding monomeric
hydroxybutyramide and – under drastic conditions, the crotylamide. One of these compounds, the 3-hydroxy-N-phenethyl-butyramide
(5), was isolated as a new natural product now.
Received: 28 March 2002/Revised version: 26 July 2002/ Accepted: 26 July 2002
RID="*"
ID="*"Marine Bakterien, XVII. XVI: R.P. Maskey, R.N. Asolkar, E. Helmke, and H. Laatsch, Chalcomycin B, a new antibiotic from
a marine Streptomyces sp. B7064. J. Antibiot., submitted 2002
Correspondence to Hartmut Laatsch, e-mail: hlaatsc@gwdg.de, Fax: +49-551-399660 相似文献
77.
Strength distributions and size effects for 2D and 3D composites with Weibull fibers in an elastic matrix 总被引:1,自引:0,他引:1
Sivasambu Mahesh S. Leigh Phoenix Irene J. Beyerlein 《International Journal of Fracture》2002,115(1):41-85
Monte Carlo simulation and theoretical modeling are used to study the statistical failure modes in unidirectional composites consisting of elastic fibers in an elastic matrix. Both linear and hexagonal fiber arrays are considered, forming 2D and 3D composites, respectively. Failure is idealized using the chain-of-bundles model in terms of -bundles of length , which is the length-scale of fiber load transfer. Within each -bundle, fiber load redistribution is determined by local load-sharing models that approximate the in-plane fiber load redistribution from planar break clusters, as predicted from 2D and 3D shear-lag models. As a result the -bundle failure models are 1D and 2D, respectively. Fiber elements have random strengths following either a Weibull or a power-law distribution with shape and scale parameters and , respectively. Under Weibull fiber strength, failure simulations for 2D -bundles, reveal two regimes: When fiber strength variability is low (roughly >2) the dominant failure mode is by growing clusters of fiber breaks, one of which becomes catastrophic. When this variability is high (roughly 0<<2) cluster formation is suppressed by a dispersed failure mode due to the blocking effects of a few strong fibers. For 1D -bundles or for 2D -bundles under power-law fiber strength, the transitional value of drops to 1 or lower, and overall, it may slowly decrease with increasing bundle size. For the two regimes, closed-form approximations to the distribution of -bundle strength are developed under the local load-sharing model and an equal load-sharing model of Daniels, respectively. The results compare favorably with simulations on -bundles with up to 1500 fibers. 相似文献
78.
A three-stage continuous culture system was used to segregate the component microbial groups of a methanogenic hexanoate-degrading association enriched from anaerobic refuse. The inhibitory effects of o-cresol concentrations (2-20 mM) on the fermentative, acetogenic, sulphate-reducing and methanogenic bacteria were then assessed in the presence of either 1.4 or 3.5 mM sulphate in the influent medium. The sulphate-reducing bacteria (SRB) in the 1.4 mM sulphate-supplemented systems were the most sensitive to o-cresol, with 29.3 and 56.6% inhibition on supplementation with 4 and 6 mM o-cresol, respectively. With 3.5mM supplementation, inhibition was 4.5 and 19.4%, respectively. Methanogenesis was not inhibited by concentrations < 10 mM o-cresol, and complete inhibition was recorded only at concentrations > or = 10 mM. Both fermentation and acetogenesis were affected by inhibition of the electron sinks. The increase in influent sulphate concentration promoted electron flow to sulphidogenesis, as predicted on thermodynamic criteria, but did not affect the relative sensitivity of the different physiological groups. 相似文献
79.
Identification of potent human anti-IL-1RI antagonist antibodies 总被引:4,自引:0,他引:4
Fredericks ZL Forte C Capuano IV Zhou H Vanden Bos T Carter P 《Protein engineering, design & selection : PEDS》2004,17(1):95-106
Interleukin-1 (IL-1) blockade by IL-1 receptor antagonist benefits some arthritis patients by reducing joint damage. This fact inspired us to develop antagonist human therapeutic antibodies against IL-1R(I) using phage libraries that display single-chain variable fragment (scFv) antibody fragments. Panning libraries against human IL-1R(I) generated 39 unique scFv-phage whose binding to IL-1R(I) was competed by IL-1 ligands. Fifteen of these scFv-phage, identified using IL-1R(I)-binding assays and dissociation rate ranking, were reformatted as scFv-Fc and IgG(4) molecules. The ease of producing antibodies in the scFv-Fc format permitted rapid identification of four lead clones (C10, C13, C14, C15) that inhibit NF-kappaB nuclear translocation induced by IL-1. Reformatting these clones as IgG(4) molecules increased their inhibition potency by =24-fold. C10 IgG(4) is the most potent antagonist of IL-1alpha (26 nM IC(50)) and IL-1beta (18 nM IC(50)) in the NF-kappaB bioassay, although less potent than IL-1ra ( approximately 0.4 nM IC(50)). C10 is the highest affinity clone for human IL-1R(I) (K(D) approximately 60 nM). Flow cytometry indicates that several lead clones bind cell-surface cynomolgus or murine IL-1R(I), characteristics advantageous for preclinical toxicology and efficacy studies. This study demonstrates the utility of scFv-Fc fusion proteins for rapid screening of clones derived from phage libraries to identify antibody leads with therapeutic potential. 相似文献
80.
José?Luis?Pe?alvoEmail author M.?Con?eic?o?Castilho M.?Irene?N.?Silveira M.?Cruz?Matallana M.?Esperanza?Torija 《European Food Research and Technology》2004,219(3):251-253
Soymilk is a water extract of soybeans, closely resembling dairy milk in physical appearance and composition. Most fatty acids in soybean and its derivates are unsaturated, and therefore susceptible to oxidation. The aim of this study was to evaluate the possible effect of the thermal conditions during the elaboration process of soymilk on its fatty acid profile. For this, the fatty acid composition of soymilk, okara (soymilk residue), and soybean were studied by gas chromatography with flame ionization detection (GC-FID). No major differences in the fatty acid patterns were found. 相似文献