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We report that using the zwitterionic detergent Zwittergent Z 3-14® to isolate outer membrane proteins (OMPs) from Salmonella O48 is suitable for their separation by two-dimensional electrophoresis (2-DE) in a capillary tube system. Sample preparation is a very crucial step for any bacterial proteomic study. Some modifications were introduced to the 2-DE protocol suggested by O'Farrell and BioRad, which significantly impaired the resolution of proteins. 2-DE analysis of OMPs may be helpful in the interpretation of the variable susceptibility of Salmonella O48 rods to the bactericidal activity of serum.
Recent years have witnessed growing interest in research on the structure and properties of proteins and peptides as physiologically active dietary components. The above has spurred a new interest in the isolation of animal, plant and microbiological peptides and investigation of their biological activity. The isolation and separation of protein and peptide mixture is not an easy procedure. Immobilised Metal Ion Affinity Chromatography (IMAC) is increasingly often used in this process. Affinity chromatography relies on the specific interactions between amino acids, their reactive groups in peptides and metal ions. The objective of this study was to determine whether copper and nickel ions can be used for the separation of peptides isolated from string beans than had been blanched and heated in a microwave oven. In this study, peptides extracted with 1% trichloroacetic acid (TCA) from string beans that had been blanched and heated in a microwave oven, were separated by chromatography on columns with copper and nickel ions immobilised through iminodiacetic acid (IDA). Peptide concentrations of the separated fractions were determined. Peptides found in string beans had similar affinity for metal ions in the Cu > Ni sequence, with selectivity in the Ni > Cu sequence. Microwave heating of string beans decreases the peptide content of extracts isolated with 1% TCA. The resulting changes are dependent on the duration of the process and the type of heating medium. Affinity chromatography with the use of metal ions immobilized to iminodiacetic acid (IDA)-Sephadex G-25 may be successfully used for the separation of peptides isolated from string beans.
Cruciferin was separated from the rapeseed crude proteins using salting out with ammonium sulphate and Sephadex G-200 gel filtration. Then, so obtained protein fraction was separated using a micellar electrokinetic chromatography (MEKC) with SDS as a the surfactant. Nine peaks with migration times between 14.33 and 20.48 min were recorded on the chromatogram. The main cruciferin subfractions were characterised with molecular mass of 22 000 and 33 000 determined using MEKC technique. UV spectra showed that cruciferin protein appears as a complex with phenolic acids.
Aerodynamic properties of solid materials have long been used to convey and separate seeds and grains duringpost harvest operations. The objective of this study was the evaluation of the aerodynamic properties of mung bean seeds as a function of moisture content and two grades referred to above and below a cut point of 4.8 mm in length. The results showed that as the moisture content increased from 7.8 to 25% (w.b.), the terminal velocity of seeds increased followinga polynomial relationship, from 7.28 to 8.79 and 6.02 to 7.12 m s-1,for grades A and B, respectively. Seeds at grade A had terminal velocities with a mean value of 8.05 m s-1, while at grade B hada mean value of 6.46 m s-1. The Reynolds number of both grades increased linearly with the increase of seeds moisture content, while the drag coefficient decreased with the increase of moisture content. Mathematical relationships were developed to relatethe change in seeds moisture content with the obtained values of aerodynamic properties. The analysis of variance showed that moisture content had a significant effect, at 1% probability level, on all the aerodynamics properties of mung beans.
Phenolic compounds from rapeseed were extracted into 80% (v/v) methanol. The crude extract was then separated using size exclusion high-performance liquid chromatography (SE-HPLC) on a TSK G2000SWXL column with a mobile phase of 45% acetonitrile and 0.1% TFA (v/v). Six peaks were identified on the chromatogram: the main peak originated from sinapin. Calibration of the assay was characterised by an excellent linearity of the sinapin standard (r2=1.0). The method so described can be used for screening phenolic constituents in rapeseed or canola. It is also useful for the purification of the sinapin as a standard from the crude extract.
Most epicuticular waxes require an initial fractionation into lipid classes prior to the further analysis. Using a silica gel column and a light-scattering detector (LSD), we developed an HPLC method to analyse and fractionate epicuticular waxes from Solanum tuberosum leaves and Plmseolus vulgaris seeds. Applying HPLC-LSD with ternary gradient clearly revealed the major peaks in potato waxes, which consist of alkanes in the C25-Cl3 range, sesquiterpene hydrocarbons, wax esters (Cj(i-C54), aldehydes (C24-C32), 2-ketones (C25-C33), 2-alkanols (C23-C!0), fatty acids (Cl6-C32), 1-alkanols (C22-C33), sterols, diols and liydroxyacids. The bean seed waxes contain n-alkanes (C25-C33), squalene, wax esters (C37-C58), fatty acids (C22-C32), 1-alkanols (CH-C35), sterols and triterpene alcohols.
This paper presents a discussion of fundamental problems of the speciation analytics of organometallic compounds occurring at low concentration levels in samples involving a complex matrix. It points out differences in analytical procedures for speciation analyses and those for determinations of total contents of a metal present in the studied sample in a number of different species.
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