Suppression of postprandial hypertriglyceridemia in rats and mice by oolong tea polymerized polyphenols

Oolong tea-polymerized polyphenols (OTPP) are characterized polyphenols produced from semi-fermented tea (oolong tea). In the present study, we evaluated the suppressive effects of oolong tea extract and OTPP on postprandial hypertriglyceridemia in rats and mice. Lymphatic recovery of triglycerides in rats cannulated in the thoracic duct was delayed by the administration of oolong tea extract at 100 and 200 mg per head, and more effectively than with green tea extract. OTPP delayed lymphatic triglyceride absorption at 20 mg/head, though (-)-epigallocatechin gallate (EGCG) did not do so at the same dose. OTPP also suppressed postprandial hypertriglyceridemia after administration of olive oil in mice. The area under the curve (AUC) of plasma triglycerides was significantly decreased, by 53% and 76%, in the 500 and 1,000 mg/kg OTPP groups respectively, as compared with the control group. These results suggest that OTPP is responsible for the suppression of hypertriglyceridemia by ingestion of oolong tea.     

反相高效液相色谱法测定石榴皮多酚类物质方法的建立及分析

建立了同时测定石榴皮多酚中绿原酸、表儿茶素、鞣花酸和槲皮素含量的反相高效液相色谱方法。采用色谱柱Hypersil ODS2(250 mm×4.6 mm,5μm),其流动相为乙腈-0.4%磷酸溶液(体积比17∶83),流速为1.0m L/min,检测波长310 nm,柱温为30℃。建立安石榴甙测量方法,色谱柱为Hypersil ODS2(250 mm×4.6 mm,5μm);流动相为甲醇-2%冰醋酸(体积比7∶93);体积流量为1.0 m L/min;检测波长为232 nm;柱温25℃。结果表明:绿原酸、表儿茶素、鞣花酸、槲皮素和安石榴甙在一定浓度范围内与峰面积呈良好的线性关系,其平均回收率分别为100.66%(RSD=2.06%)、100.05%(RSD=0.58%)、100.05%(RSD=0.51%)、99.51%(RSD=1.22%)和99.79%(RSD=0.52%)。此结果说明反相高效液相色谱可用于测定石榴皮多酚类物质。     

Characterization of polysaccharide-protein complexes by size-exclusion chromatography combined with three detectors

Two water-soluble samples (TM1 and TM2) were extracted from Pleurotus tuber-regium using 0.9% aqueous NaCl at 20 and 80 degrees C to obtain relatively low molecular mass fractions. The chemical structure of TM1 was analyzed to be a branched heteropolysaccharide-protein complex, and the sugar moiety was mainly beta-(1-->6)-, beta-(1-->4)-, and beta-(1-->3)-linked glucan containing galactose and mannose. TM2 was a branched polysaccharide-protein complex, and the sugar moiety was mainly beta-(1-->6)-, beta-(1-->4)-, and beta-(1-->3)-linked glucan. Preparative size-exclusion chromatography (SEC) and analytical SEC combined with three detectors were used to detect the TM1 and TM2 samples, confirming that the proteins were bonded to the polysaccharides. Furthermore, analytical SEC combined with online laser light scattering, differential refractive index detector, and UV to determine the components, weight-average molecular mass (M(w)) and chain conformation of the samples. The relatively low exponent values (nu) of S(2)(z)(1/2)=k(nu)M(w)(nu) for the samples in 0.15M aqueous NaCl at 25 degrees C suggested that TM1 and TM2 existed in compact sphere conformation in the aqueous solution. This work provided valuable information on the structure and chain conformation characterization of the polysaccharide-protein complex having relatively low M(w).     

Characterization of uterine estrogen receptors by size-exclusion and ion-exchange high-performance liquid chromatography

This report presents the first application of ion-exchange high-performance liquid chromatography in the study of ER from the rabbit uterus. In the presence of sodium molybdate (20 mM), native ER was eluted as a sharp peak at 0.29 M NaCl by a linear salt gradient, but without molybdate, it resolved into 4 major peaks. Molybdate-stabilized ER from the DEAE column, similar to ER from crude cytosol, sedimented at the 6-8S region in low salt and 4S region in high salt linear sucrose gradients, and was excluded from size-exclusion HPLC. In contrast, dissociated ER subunits from DEAE eluates ranged from 3.5 to 4.5S, and showed differences in molecular weights in a size-exclusion column. These results show that the native ER is a large molecule which dissociates into smaller subunits in the absence of molybdate; each of the steroid-bound moieties differs in molecular weight and surface charge from the native molecule.     

Characterization of peroxidase:anti-peroxidase immune complexes by capillary zone electrophoresis and high-performance size-exclusion chromatography

Determination of the molecular constituents of commercial peroxidase:anti-peroxidase (PAP) preparations is necessary for the proper interpretation of PAP applications based on competitive binding assay. Capillary zone electrophoresis with field 300 V/cm, 40 cm capillary length (20 cm effective length), and high-performance size exclusion chromatography equipped with Superose12 HR10/30 column revealed that a PAP preparation used for Fcγ receptor studies contained multiple sizes of immune complexes, an excess amount of free peroxidase, and little or no free anti-peroxidase antibody. The antibody:antigen ratios of the three major immune complex components were 2:2, 1:2, and 1:1. These techniques provide useful methods of qualitative, as well as quantitative analysis of PAP preparations.     

A deadenylase assay by size-exclusion chromatography

The shortening of the 3'-end poly(A) tail, also called deadenylation, is crucial to the regulation of mRNA processing, transportation, translation and degradation. The deadenylation process is achieved by deadenylases, which specifically catalyze the removal of the poly(A) tail at the 3'-end of eukaryotic mRNAs and release 5'-AMP as the product. To achieve their physiological functions, all deadenylases have numerous binding partners that may regulate their catalytic properties or recruit them into various protein complexes. To study the effects of various partners, it is important to develop new deadenylase assay that can be applied either in vivo or in vitro. In this research, we developed the deadenylase assay by the size-exclusion chromatography (SEC) method. The SEC analysis indicated that the poly(A) or oligo(A) substrate and the product AMP could be successfully separated and quantified. The enzymatic parameters of deadenylase could be obtained by quantifying the AMP generation. When using the commercial poly(A) as the substrate, a biphasic catalytic process was observed, which might correlate to the two distinct states of poly(A) in the commercial samples. Different lots of commercial poly(A) had dissimilar size distributions and were dissimilar in response to the degradation of deadenylase. The deadenylation pattern, processive or distributive, could also be investigated using the SEC assay by monitoring the status of the substrate and the generation kinetics of AMP and A2. The SEC assay was applicable to both simple samples using the purified enzyme and complex enzyme reaction conditions such as using protein mixtures or crude cell extracts as samples. The influence of solutes with absorption at 254 nm could be successfully eliminated by constructing the different SEC profiles.     

Determination of polyanionic macromolecules by size-exclusion chromatography

This report presents an extension of a method developed for determination of dextran sulfate in rat serum. The drug is a negatively charged polysaccharide with a molecular mass of 8000. It is fractionated by molecular size and separated from serum components by high-performance size-exclusion chromatography. Sensitive detection is achieved by the post-column complexation of the analyte with 1,9-dimethylmethylene blue (DMMB). A metachromatic complex is formed; the absorbance maximum of the complex is shifted from that of the free dye. Various glycosaminoglycans and other macromolecular polyanions interact with DMMB. Several can be determined using the chromatographic conditions developed for dextran sulfate. The method provides a simple procedure for quantitation of these compounds. Compared to spectrophotometric assays, less sample preparation is required, selectivity is enhanced, and molecular mass information is provided. With modification of eluent composition, dye concentration, and detection wavelength, the method can be validated for determination of additional compounds.     

Characterization of yeast amylolytic enzymes by HPLC maltooligosaccharides determination

Summary A simple method for determination of starch hydrolysis degree by measurement of maltooligosaccharides using HPLC on SGX C-18 column with deionised water as mobile phase was presented. Separation of seven oligosaccharides in an order from glucose to maltoheptaose illustrated the action of two enzyme systems taking part of starch hydrolysis and following fermentation to ethanol.     

Characterization of a polysaccharide-protein complex from Ganoderma tsugae mycelium by size-exclusion chromatography combined with laser light scattering

A water-soluble polysaccharide-protein complex (GM3) extracted from the mycelium of Ganoderma tsugae was characterized using size-exclusion chromatography combined with laser light scattering (SEC-LLS). Two peaks coded as fractions I and II appeared in the SEC pattern of GM3 in 0.5 M NaCl aqueous solution, corresponding to the weight-average molecular mass (M(w)) of 355 x 10(4) and 6.3 x 10(4), respectively. The relationship between the radius of gyration ((z)(1/2)) and M(w) showed that molecules of fraction I exhibited more compact coil conformation than that of fraction II in 0.5 M NaCl aqueous solution at 25 degrees C. To clarify the component of polysaccharide and protein in each fraction, the sample GM3 was treated with 0.2 M NaOH aqueous solution to degrade polysaccharide and trypsin to hydrolyze protein. The obtained products were analyzed by SEC combined with detectors such as UV, differential refractive index (DRI) and LLS. The results indicated that both the fractions I and II were protein-bound polysaccharide, but had different protein content and degree of branching, resulting in the difference of the chain conformation.     

Analyses of polyphenols in cacao liquor, cocoa, and chocolate by normal-phase and reversed-phase HPLC

The antioxidant polyphenols in cacao liquor, a major ingredient of chocolate and cocoa, have been characterized as flavan-3-ols and proanthocyanidin oligomers. In this study, various cacao products were analyzed by normal-phase HPLC, and the profiles and quantities of the polyphenols present, grouped by molecular size (monomers to approximately oligomers), were compared. Individual cacao polyphenols, flavan-3-ols (catechin and epicatechin), and dimeric (procyanidin B2), trimeric (procyanidin C1), and tetrameric (cinnamtannin A2) proanthocyanidins, and galactopyranosyl-ent-(-)-epicatechin (2alpha-->7, 4alpha-->8)-(-)-epicatechin (Gal-EC-EC), were analyzed by reversed-phase HPLC and/or HPLC/MS. The profile of monomers (catechins) and proanthocyanidin in dark chocolate was similar to that of cacao liquor, while the ratio of flavan-3-ols to the total amount of monomeric and oligomeric polyphenols in the case of pure cocoa powder was higher than that in the case of cacao liquor or chocolate.     

Refolding of denatured thioredoxin observed by size-exclusion chromatography

Molecular sieve chromatography can resolve interactive systems into populations having different effective hydrodynamic volumes. In this report, the advantages of such resolution to protein folding are illustrated by using moderate pressure to decrease analysis time and lowered temperature to slow down the kinetics of conformational change. A 300-mm Bio-Sil TSK-125 size-exclusion column was equilibrated with a series of different concentrations of guanidine hydrochloride at 2 degrees C in 50 mM phosphate buffer, pH 7.0. Samples of native Escherichia coli thioredoxin, denatured thioredoxin, or thioredoxin equilibrated with the column solvent were injected, and the effluent was monitored at 220 nm. Injection of equilibrated protein samples defined three denaturant concentration zones identical with those observed by spectral measurements: the native base-line zone where only compact protein is observed in the effluent profile; the transition zone in which both compact and denatured forms are observed in slow exchange; and the denatured base-line zone in which only denatured protein is observed. Unfolding was observed by injection of native protein into columns having isocratic denaturant concentrations in the transition and denatured base-line zones. Effluent profiles indicated a dynamic conversion of compact to denatured protein with a time constant which appeared to decrease markedly with increasing denaturant concentration. Refolding was observed by injection of denatured protein into columns having isocratic concentrations in the transition and native base-line zones. As the denaturant concentration was decreased, the effluent profiles evidenced a persistent slow conversion of denatured to compact protein which was suddenly accelerated about midway in the native base-line zone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of in vitro proteolytic processing of beta-endorphin by reversed-phase HPLC

In vitro, central and peripheral proteolytic processing of beta-endorphin by membrane-bound enzymes results in the formation of specific active fragments that have been recently shown to function in behavior, intestinal motility and in the central control of urinary bladder activity. A high resolution, reversed phase high performance liquid chromatography system capable of separating 28 beta-endorphin related fragments simultaneously was used to study the time-course processing of beta-endorphin by membrane associated peptidases in the brain and regions of the small intestine. The hypothesis we tested was that a homeostatic balance between alpha- and gamma-type endorphins exists in these tissues. The results of the study show that the rate and quantity of fragments produced between the mucosa and nerve-muscle regions of the small intestine are significantly different. Metabolic rates, pattern, and the ratio of alpha/gamma-type endorphins in the brain were very similar to the nerve-muscle region of the small intestine. This suggests that beta-endorphin processing to active fragments is occurring at the nerves of the small intestine and that a specific and similar balance of alpha/gamma-type endorphin exists in the brain and gastrointestinal system at neutral pH.     

Characterization of casein peptones by HPLC profiles and microbiological growth parameters

Thirty six pancreatic casein peptones from various producers were analyzed by HPLC and by microbiological growth tests. The data were compared by using the principal coordinate analysis and simple mathematical tests. The Proteose peptone quotient, PQ1, determined by the growth of Escherichia coli, separated these casein peptones into three groups, depending on their suitability as nutrients compared to Proteose peptone as a standard. These groups corresponded to the HPLC patterns, characterized by the specific peaks of polypeptides, peptides and amino acids, respectively. The peaks of the high-molecular weight polypeptides were negatively correlated with the growth parameters. The peptides of a low molecular weight promoted the growth of Staphylococcus aureus with and without the exhaustion of usable N compounds and in the presence and absence of glucose (PQ2 and PQ3). The colony sizes correlated weakly with certain peaks only. HPLC patterns, thus, seem to be useful for the characterization of casein peptones for the standardization of nutrient media as well as for special applications.     

Cancer chemoprevention by tea polyphenols

Tea is one of the most widely consumed beverages, second only to water. Many experimental researches in laboratory animals demonstrated that tea components had an inhibitory effect on carcinogenesis at a number of organ sites. The inhibitory effects of tea against carcinogenesis have been attributed to the biologic activities of the polyphenol fraction in tea. This review summarizes experimental data on chemopreventive effects of tea polyphenols in various tumor bioassay systems. Many laboratory studies have demonstrated the inhibitory effects of green tea polyphenols, especially (-)-epigallocatechin-3-gallate (EGCG), on carcinogenesis in animals models. The majority of these studies have been conducted in mouse skin tumor models, where tea polyphenols were used either as oral feeding in drinking water or in direct local application. Most studies used 12-O-tetradecanoylphorbol-13-acetate (TPA) or ultraviolet (UV) radiation as the tumor promoter and found anticarcinogenic effects caused by green tea polyphenols. Black tea was also found to be effective, although the activity was weaker than that of green tea in some experiments. Other studies showed that black tea polyphenols-theaflavins exhibited stronger anticarcinogenic activity than did EGCG. Caffeine in tea was also important for tea to prevent tumorigenesis. The molecular mechanisms of the cancer chemopreventive effects of tea polyphenols are not completely understood. They are most likely related to the mechanisms of biochemical actions of tea polyphenols, which include antioxidative activities, modulation of xenobiotic metabolite enzymes and inhibition of tumor promotion. In addition, we have also proposed that tea polyphenols function as cancer chemopreventive agents through modulation of mitotic signal transduction. However, the molecular mechanisms involved in this modulation need further investigation.     

Acetate-enhanced polymerized triacylglycerol utilization by Mucor circinelloides

We found that laboratory-prepared sunflower oil waste containing polymerized triacylglycerols (PTAGs) still within South African regulatory levels (i.e. 1, 5, 10 and 15% w/w) is effectively degraded by the fungus Mucor circinelloidesin the presence of acetate. Poor utilization was experienced in its absence. These results suggest that fungi could be used in oil waste removal, while at the same time biomass, rich in essential fatty acids such as linoleic and gamma-linolenic acid is produced.     

Characterising protein/detergent complexes by triple-detection size-exclusion chromatography

Background

The number of species with completed genomes, including those with evidence for recent whole genome duplication events has exploded. The recently sequenced Atlantic salmon genome has been through two rounds of whole genome duplication since the divergence of teleost fish from the lineage that led to amniotes. This quadrupoling of the number of potential genes has led to complex patterns of retention and loss among gene families.

Results

Methods have been developed to characterize the interplay of duplicate gene retention processes across both whole genome duplication events and additional smaller scale duplication events. Further, gene expression divergence data has become available as well for Atlantic salmon and the closely related, pre-whole genome duplication pike and methods to describe expression divergence are also presented. These methods for the characterization of duplicate gene retention and gene expression divergence that have been applied to salmon are described.

Conclusions

With the growth in available genomic and functional data, the opportunities to extract functional inference from large scale duplicates using comparative methods have expanded dramatically. Recently developed methods that further this inference for duplicated genes have been described.

     

Characterization of a more electronegatively charged LDL subfraction by ion exchange HPLC

Low density lipoproteins (LDL), collected from 32 normal male subjects (aged 30-60), were subfractionated by high resolution ion exchange chromatography (IE-HPLC). By this procedure two LDL subfractions were eluted. The first corresponds to normal LDL (nLDL); while the second one corresponds to a more electronegative subfraction, called LDL-. The mean percentage contribution of LDL- to native plasma LDL was of 3.9% (range 0.5-9.8%). The percentage concentration of LDL- in total native LDL did not correlate with plasma total cholesterol, triglycerides, and LDL cholesterol, whereas a significant negative correlation with high density lipoprotein cholesterol was found (r = -.38; p less than .05). LDL- was negatively correlated with LDL phospholipids (r = -.59; p less than .001), and with the LDL vitamin E content (r = -.63; p less than .001), and positively correlated with LDL proteins (r = -.35; p less than .05) and the content of thiobarbituric acid reactive substances (TBARS) in total LDL (r = .43; p less than .05). The TBARS molar content of LDL- was three times higher than in nLDL, with a mean concentration in LDL- of 7.3 mol/mol lipoprotein. By preparative IE-HPLC significant differences of the LDL- chemical composition were observed. The percentage content of cholesterol esters and of phospholipids was decreased, whereas proteins and free cholesterol were increased. Analysis by sodium dodecyl sulphate polyacrylamide gel electrophoresis revealed that besides apolipoprotein B-100 there was evidence of peptides with a higher molecular weight in LDL-.(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of osmotic second virial coefficients by zonal size-exclusion chromatography

Numerical simulation of protein migration reflecting linear concentration dependence of the partition isotherm has been used to invalidate a published procedure for measuring osmotic second virial coefficients (B₂₂) by zonal exclusion chromatography. Failure of the zonal procedure to emulate its frontal chromatographic counterpart reflects ambiguity about the solute concentration that should be used to replace the applied concentration in the rigorous quantitative expression for frontal migration; the recommended use of the peak concentration in the eluted zone is incorrect on theoretical grounds. Furthermore, the claim for its validation on empirical grounds has been traced to the use of inappropriate B₂₂ magnitudes as the standards against which the experimentally derived values were being tested.     

Rapid characterization of cellular retinoid-binding proteins by high-performance size-exclusion chromatography

A high-performance size-exclusion chromatographic method was developed for the analysis of cellular retinol and retinoic acid-binding proteins. The chromatographic analysis of the retinol-retinol-binding protein complex or the retinoic acid-retinoic acid-binding protein complex requires 15 min. The use of high-specific-radioactivity retinoid ligand (30-40 Ci/mmol) allows routine detection of 25 fmol of retinoid-binding protein/mg of cytosolic protein. Thus, this method provides a rapid alternative to sucrose density gradient sedimentation analysis of the cellular retinoid-binding proteins. High-performance size-exclusion chromatography is well suited to screening novel tissues, tumors, and cell lines for the presence of retinoid-binding proteins and to the further characterization of these cellular proteins. This method was applied to the characterization of cellular retinol- and retinoic acid-binding proteins in fetal rabbit tissues. Both retinol- and retinoic acid-binding proteins were detected in fetal rabbit brain, intestine, kidney, and lung at a gestational age of 28 days. Neither retinoid-binding protein was detected in 28-day-old fetal rabbit placenta. Specific retinoic acid binding in fetal intestinal cytosol decreased as a function of increasing gestational age.