Determination of heat-stable exotoxin of Bacillus thuringiensis by high-performance anion-exchange chromatography

A high-performance anion-exchange chromatography method for quantitative determination of heat-stable exotoxin in insecticide preparations and cultivation liquids is described. Heat-stable exotoxin-containing samples were chromatographed in a column packed with anion-exchange resin under gradient elution conditions, using HCl and NaCl solution, at 50°C. The calibration was linear in the exotoxin concentration range from 1 to 100 mg/ml. The sensitivity of the method allows one to determine 1 nmol and more of the heat-stable exotoxin in the applied sample, the relative standard deviation being not more than ±4%.     

Degree of acetylation of heteropolysaccharides

The acetyl groups in polysaccharides and glycoproteins have been determined using 4 N HCl at 120 degrees C for acid hydrolysis. Acetic acid and hexosamine were determined by high-performance cation-exchange chromatography with UV detection and high-performance anion-exchange chromatography with pulsed amperomeric detection, respectively. The method compares well with other procedures and shows an additional advantage of being able to analyze for hexosamine in the same hydrolyzate, thus permitting the degree of acetylation of hexosamine-containing biopolymers to be determined directly without correction for additional components in the material of interest.     

Approach to the large-scale preparation of highly pure phosphatidylserine from bovine brain

An approach to the large-scale preparation of highly pure phosphatidylserine from bovine brain is described in this paper. The method is based on (i) the separation of phosphatidylserine from phosphatidylinositol in bovine brain extract by preparative aminopropyl normal-phase high-performance liquid chromatography using methanol-1 1 M phosphoric acid (90:10, v/v) as mobile phase (ii)_further purification of phosphatidylserine by anion-exchange chromatography. The main advantage of this approach is that polyunsaturated acid-containing molecular species of brain phosphatidylserine are not lost in the preparation procedure.     

Evaluation of high-performance liquid chromatography for the separation and determination of arsenic species by on-line high-performance liquid chromatographic-hydride generation-atomic absorption spectrometry

An on-line high-performance liquid chromatographic-microwave assisted oxidation-hydride generation-atomic absorption spectrometric (HG-AAS) system (using columns of different kinds) has been developed for the determination of arsenite, arsenate, dimethylarsinate (DMA), monomethylarsonate (MMA), arsenobetaine (AsB) and arsenocholine (AsC) in environmental samples. Ion-pair reversed-phase chromatography using tetrabutylammonium phosphate as the ion-pair reagent and anion-exchange chromatography were evaluated and the analytical performances of each are reported. The detection limits were 97–143 and 10–30 μg l⁻¹ for ion-pair reversed-phase and anion-exchange chromatography, respectively. The Hamilton PRP-X 100 anionic column was proposed for the determination of the six species; AsB can be quantitated independently of AsC by taking the difference between readings at pH 6 and pH 10.7. The proposed methods were applied to water samples and sediments and their potential for future application was demonstrated.     

25-Hydroxyvitamin D3 3-sulphate is a major circulating form of vitamin D in man

25-Hydroxyvitamin D3 3 beta-sulphate has been identified in human plasma. The compound was isolated by anion-exchange chromatography and following hydrolysis it was characterized by high-performance liquid chromatography and gas chromatography-mass spectrometry. The mean concentration of sulphated 25-hydroxyvitamin D3 in plasma from 60 patients was 16.7 +/- 7.1 ng/ml and the levels often exceeded those of the corresponding free compound. The study also shows that unconjugated 25-hydroxyvitamin D3 is not readily sulphated by man in vivo.     

Cell-associated glucans of Burkholderia solanacearum and Xanthomonas campestris pv. citri: a new family of periplasmic glucans.

The cell-associated glucans produced by Burkholderia solanacearum and Xanthomonas campestris pv. citri were isolated by trichloroacetic acid treatment and gel permeation chromatography. The compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry, and high-performance anion-exchange chromatography. B. solanacearum synthesizes only a neutral cyclic glucan containing 13 glucose residues, and X. campestris pv. citri synthesizes a neutral cyclic glucan containing 16 glucose residues. The two glucans were further purified by high-performance anion-exchange chromatography. Methylation analysis revealed that these glucans are linked by 1,2-glycosidic bonds and one 1,6-glycosidic bond. Our 600-MHz homonuclear and 1H-13C heteronuclear nuclear magnetic resonance experiments revealed the presence of a single alpha-1,6-glycosidic linkage, whereas all other glucose residues are beta-1,2 linked. The presence of this single alpha-1,6 linkage, however, induces such structural constraints in these cyclic glucans that all individual glucose residues could be distinguished. The different anomeric proton signals allowed complete sequence-specific assignment of both glucans. The structural characteristics of these glucans contrast with those of the previously described osmoregulated periplasmic glucans.     

Simultaneous LC-MS/MS Analysis of Glyphosate,Glufosinate, and Their Metabolic Products in Beer,Barley Tea,and Their Ingredients

Glyphosate and glufosinate are non-selective herbicides that have been extensively used worldwide. Their ionic and water-soluble characteristics often make it difficult to analyze them, especially in food components. A method was developed in this study for the simultaneous analysis of glyphosate, glufosinate, and three metabolic products in beer, barley tea, and their ingredients (malt and corn). The analytical samples were extracted with H₂O, purified with a strong anion-exchange solid-phase extraction (SPE) cartridge, and then analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) with an anion-exchange high-performance liquid chromatography (HPLC) column. This method enabled a rapid and sensitive analysis [limit of quantification (LOQ) = 10 µg/kg] of the herbicides to be achieved.     

In Vitro Biosynthesis of Phosphorylated Starch in Intact Potato Amyloplasts

Intact amyloplasts from potato (Solanum tuberosum L.) were used to study starch biosynthesis and phosphorylation. Assessed by the degree of intactness and by the level of cytosolic and vacuolar contamination, the best preparations were selected by searching for amyloplasts containing small starch grains. The isolated, small amyloplasts were 80% intact and were free from cytosolic and vacuolar contamination. Biosynthetic studies of the amyloplasts showed that [1-¹⁴C]glucose-6-phosphate (Glc-6-P) was an efficient precursor for starch synthesis in a manner highly dependent on amyloplast integrity. Starch biosynthesis from [1-¹⁴C]Glc-1-P in small, intact amyloplasts was 5-fold lower and largely independent of amyloplast intactness. When [³³P]Glc-6-P was administered to the amyloplasts, radiophosphorylated starch was produced. Isoamylase treatment of the starch followed by high-performance anion-exchange chromatography with pulsed amperometric detection revealed the separated phosphorylated α-glucans. Acid hydrolysis of the phosphorylated α-glucans and high-performance anion-exchange chromatography analyses showed that the incorporated phosphate was preferentially positioned at C-6 of the Glc moiety. The incorporation of radiolabel from Glc-1-P into starch in preparations of amyloplasts containing large grains was independent of intactness and most likely catalyzed by starch phosphorylase bound to naked starch grains.     

Rapid purification of human placental aldose reductase

Sixty percent methanol is widely used for the extraction of nucleotides from lymphocytes for quantitation by high-performance liquid chromatography. In the course of such studies, we noted that these extracts analyzed on an anion-exchange column showed a major “unknown” uv-absorbing peak which eluted after the nucleosides and before the nucleotides. The material cochromatographed with and had the spectral properties of ascorbic acid. This compound was identified as ascorbic acid by chemical and enzymatic assays. The ascorbate content of human lymphocytes determined by high-performance liquid chromatography, $\text{42.2 ± 3.3 nmol}\text{10}{}^8$ cells (mean ± SEM), agreed closely with the levels obtained by standard less sensitive methodology. Evidence is presented that this technique can be used to determine the ascorbate content of lymphocytes where only scanty material or very low levels are found.     

Granule size affects the acetyl substitution on amylopectin populations in potato and sweet potato starches

Specific enzymatic degradation in combination with chromatographic and spectrometric techniques was used to understand acetyl group distribution over the amylopectin populations of differently sized granule fractions from potato and sweet potato starches. The hydrolysates obtained after -amylase, ß-amylase, pullulanase, and the combination of pullulanase, -amylase and amyloglucosidase treatment were investigated by high-performance size-exclusion chromatography (HPSEC), high-performance anion-exchange chromatography (HPAEC) and Maldi-Tof-MS (Matrix-Assisted Laser Desorption/Ionisation Time-Of-Flight Mass Spectrometry). The acetyl groups were found to be located near the branching point, in the external chain and in the internal chain regions. The acetyl group distributions were different for amylopectin from different granule size fractions. Higher DP (degree of polymerization) fragments were present in the digests of acetylated amylopectin populations of the small size granule starches. Our studies confirmed that acetyl groups were unevenly distributed over the amylopectin populations.     

Acetylcholine measurement by high-performance liquid chromatography using an enzyme-loaded postcolumn reactor

Choline oxidase and cholinesterase were found to retain their activity for 1-2 weeks at room temperature while adsorbed to a commercially available anion-exchange cartridge. These enzymes convert acetylcholine to H2O2. Acetylcholine can be measured in tissue extracts by separation at pH 7 on a polymeric reverse-phase high-performance liquid chromatography column, conversion of acetylcholine to H2O2 on a postcolumn enzyme-loaded anion-exchange cartridge, and electrochemical detection of the H2O2 formed.     

Purification, characterization, and fibrinogen cleavage sites of three fibrinolytic enzymes from the venom of Crotalus basiliscus basiliscus.

Three distinct fibrinolytic enzymes have been purified from the venom of Crotalus basiliscus basiliscus (the Mexican west coast rattlesnake). The high-performance liquid chromatography-based purification comprised the following steps: (a) hydrophobic interaction chromatography; (b) hydroxylapatite chromatography; (c) anion-exchange chromatography. Following hydrophobic interaction chromatography two fibrinolytic activity peaks were detected, Cbfib1 and Cbfib2. Cbfib2 was rendered homogeneous following hydroxylapatite chromatography. Upon hydroxylapatite chromatography Cbfib1 was shown to consist of two components, Cbfib1.1 and Cbfib1.2. Both Cbfib1.1 and Cbfib1.2 were purified to homogeneity using anion-exchange chromatography. SDS-polyacrylamide gel electrophoresis revealed that Cbfib1.1 and Cbfib1.2 had similar molecular weights (approximately 23,500), whereas Cbfib2 displayed a molecular weight of approximately 22,500. The enzymes do not appear to be glycosylated. Tryptic digests of all three enzymes, analyzed by high-performance reverse-phase chromatography, suggest that Cbfib1.1 and Cbfib1.2 are closely related and different from Cbfib2. The latter displayed more similarity with Cbfib1.2 than with Cbfib1.1. Specific fibrinolytic activity for all three enzymes was very similar, but general proteolytic activity varied substantially with Cbfib2 showing a 12-fold higher specific proteolytic activity when compared to Cbfib1.1 and Cbfib1.2. None of these enzymes exhibited hemorrhagic activity when injected (up to 100 micrograms) subcutaneously into mice. Cbfib1.1 and Cbfib1.2 action against fibrinogen was directed equally against both the A alpha- and B beta-chains. Against fibrin the rate of degradation of the alpha-chain was considerably higher than that of the beta-chain. Cbfib2 showed mainly alpha-fibrin(ogen)ase activity with limited activity on the beta-chain. Several fibrinogen cleavage sites on the A alpha-chain have been identified: Cbfib1.1 and Cbfib1.2 cleave at Lys413-Leu414, Ser505-Thr506, and Tyr560-Ser561. Cbfib2 cleaves mainly at Gly254-Ser255 and Pro516-Met517.     

An optimized fast-performance liquid chromatography method for analyzing lipoprotein profiles using microliter volumes of serum

Plasma or serum lipoprotein analysis is commonly carried out with a conventional size-exclusion fast-performance liquid chromatography method that requires large sample volumes (1-2 ml). To determine lipoprotein profiles of mice with this method, plasma or serum samples have to be pooled from a group of animals, which often requires sacrificing animals. Here we report an optimized anion-exchange chromatography method with simplified cholesterol collection and detection system. After 5-10 μl serum was injected for anion-exchange chromatography, a stepwise gradient was applied and fractions were collected on a 96-well plate. Cholesterol content in each well was measured using a fluorescence-based detection method. With this method, distinct lipoprotein peaks corresponding to high-density lipoprotein, low-density lipoprotein, and very-low-density lipoprotein, can be easily separated and identified with excellent resolution. The entire high-performance liquid chromatography run takes about 30 min and the results are reproducible with a low variability. The small sample size allows analyzing the lipoprotein profile in a given mouse at a given time point with nonterminal bleeding. The method is simple to set up with commercially available parts and convenient to run.     

A high-performance liquid chromatographic technique that separates cellular retinol binding protein from cellular retinoic acid binding protein

A one-step procedure to detect cellular [3H]retinol and [3H]retinoic acid binding proteins (CRBP and CRABP) from rat testis cytosolic extract was devised. The procedure is based on anion-exchange high-performance liquid chromatography of the cytosolic fraction on columns of Mono Q, which permits elution of CRABP and CRBP at 12 and 22 min, respectively.     

Factor 390 chromophores: phosphodiester between AMP or GMP and methanogen factor 420

Two chromophores with absorbance maxima at 390 nm (factors 390) have been isolated from oxidized cells of Methanobacterium thermoautotrophicum delta H. The isolation procedure included anion-exchange chromatography of the soluble cofactor pool followed by reverse-phase chromatography. The factor 390 species are novel derivatives of methanogen coenzyme factor 420 in which the 5-deazaflavin 8-hydroxy group is in a phosphodiester linkage to adenosine 5'-phosphate or guanosine 5'-phosphate. The structural assignments were based, in part, on the UV-visible and 1H NMR spectra. In addition, the results from amino acid analysis, phosphate determination, 31P NMR spectroscopy, and fast atom bombardment mass spectrometry were consistent with the proposed structures. Confirmation of the factor 390 structures was made following phosphodiesterase release of the nucleotide monophosphates from factor 420. The nucleotide monophosphates were identified as AMP and GMP by UV-visible spectra and based on elution position by using reverse-phase and anion-exchange high-performance liquid chromatography. The presence of AMP was further demonstrated by using adenylate-5'-phosphate kinase which induced a spectral shift during conversion of the sample to IMP. In addition, the presence of GMP was established by a specific enzymatic assay.     

Partial depolymerization of pectin by a photochemical reaction

Complex heterogeneous polysaccharides that comprise pectin were partially depolymerized by a photochemical reaction using ultraviolet light in the presence of titanium dioxide catalyst. In a period of 6 h at pH 7, this UV/TiO₂ process decreased the average molecular weight of pectin from 400 kDa to 200 kDa. The characterization of the partially depolymerized pectin, which was fractionated by size-exclusion chromatography, was performed by ¹H NMR spectroscopy, and the spectra obtained showed that the resulting oligosaccharides and polysaccharides maintained the intact core structure of pectin. The monosaccharide content and depolymerization profile were determined by high-performance anion-exchange chromatography coupled with pulsed amperometric detection. This controlled photochemical depolymerization technique might be useful for preparation of pectin oligosaccharides as an ingredient in food and pharmaceutical products.     

Extent of peptidoglycan O acetylation in the tribe Proteeae.

The degree of peptidoglycan O acetylation in 18 strains of the different genera of the tribe Proteeae (Proteus, Providencia, and Morganella) has been determined by high-performance liquid chromatography-based organic acid analysis of mild-base-released acetic acid and quantitation of peptidoglycan concentrations by simultaneous amino sugar-amino acid analysis using high-performance anion-exchange chromatography with pulsed amperometric detection. The N,O-diacetylmuramyl content of all isolated and purified peptidoglycans was greater than 29% and ranged up to 57% relative to total muramic acid concentration. Each of the O-acetylated peptidoglycans was found to be resistant to solubilization by hen egg white lysozyme.     

Sequence of a tryptic peptide from the NADPH binding site of the enoyl reductase domain of fatty acid synthase

Fatty acid synthase from the uropygial gland of goose was inhibited by treatment with pyridoxal 5'-phosphate by selectively modifying a lysine residue at the NADPH binding site of the enoyl reductase domain (A. J. Poulose and P. E. Kolattukudy (1980) Arch. Biochem. Biophys. 201, 313-321). Distribution of radioactivity in tryptic peptides generated from the synthase treated with pyridoxal 5'-phosphate/NaB3H4 in the presence and absence of 2'-monophosphoadenosine-5'-diphosphoribose, which protects the enzyme from inactivation by pyridoxal phosphate, showed that modification of one specific peptide was prevented by the protector. This peptide was purified by a combination of Sephadex G-25 column chromatography, anion-exchange chromatography, and high-performance liquid chromatography. The primary structure of this peptide is Val-Phe-Thr-Thr-Val-Gly-Ser-Ala-Glu-Lys(Pxy)-Arg.     

Water Soluble Pigments Containing Xylose and Glucose in Gametangia of the Green Alga, Bryopsis maxima

Several water-soluble pigments were purified from gametangiaof Bryopsis maxima by liquid chromatography and characterizedby pyridylamination and high-performance anion-exchange chromatography.The structure of the main red pigment is proposed based on thedata of infrared spectrum, Mass spectrum, ¹H and ¹³C NMR spectraand pyridylamino analysis. As a consequence, this pigment containeda tetrapyrrole with phytol and a sugar chain comprised of xyloseand glucose. The sequence of the sugars in the chain was determinedbased on its Mass spectrum. The pigment was similar to chlorophyll-originpigments observed in other plants. No aldehyde group, however,was present at C5 in the open tetrapyrrole chain. (Received August 3, 1994; Accepted November 10, 1994)     

Rapid and simple method for the determination of α1-acid glycoprotein in serum by column liquid chromatography

A rapid and simple method for the determination of α₁-acid glycoprotein (AAG) in serum was developed by using an anion-exchange column for clean-up of serum and a hydroxyapatite column for high-performance liquid chromatography (HPLC). A good correlation was observed between this HPLC method and the conventional radial immunodiffusion method. The method may also be used to determine the AAG concentration in the serum of experimental animals.