Vicinal Diol Groups Research Articles

Self-Assembled Monolayers with Latent Aldehydes for Protein Immobilization

Aldehyde functions are widely used for immobilization of biomolecules on glass surfaces but have found little attention for biofunctionalization of self-assembled monolayers (SAMs) on gold, due to interference between thiol and aldehyde functions. This problem was recently solved by synthesis of an alkanethiol that carried a vicinal diol group [Jang et al. (2003) Nano Lett. 3, 691-694]. The latter served as a latent aldehyde function that was unmasked by short exposure of the vicinal diol-terminated SAM to aqueous periodate. However, the synthesis of the new vicinal diol-terminated alkane thiol was time-consuming and had an overall yield of approximately 3.5%. In the present study, a general modular strategy was introduced by which SAM components with vicinal diol functions were rapidly synthesized with high yield: this was accomplished by amide bond formation between a SAM-forming carboxylic acid (exemplified by lipoic acid and 16-mercaptohexadecanoic acid) with 3-aminopropane-1,2-diol, using suitable protecting groups. The disulfide or free thiol group afforded SAM formation on gold and, after periodate oxidation of the vicinal diol functions, proteins were covalently bound via their lysine residues. At 1 mg/mL protein concentration, complete surface coverage was reached within minutes. No further protein was bound by nonspecific adsorption, but cognate proteins were specifically bound with high capacity. Pyrogallol-O-hexadecanoic acid and 10-undecenoic acid were also coupled with 3-aminopropane-1,2-diol by amide bond formation, thereby producing latent aldehyde-containing SAM components for metal oxides and hydrogen-terminated silicon, respectively, to show the general usefulness of the new synthetic design.

Chiral Separation of Synthetic Vicinal Diol Compounds by Capillary Zone Electrophoresis with Borate Buffer and b-Cyclodextrin as Buffer Additive

The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.

Cytochemical characterization of glycoconjugates in the apocrine glands of the equine scrotal skin

Cytochemistry of glycoconjugates in the apocrine glands in the scrotal skin of the horse was studied using cytochemical methods for electron microscopy, particularly lectin cytochemistry. The secretory cells possessed a variable number of secretory vesicles, a well-developed Golgi apparatus, and abundant cisternae of the rough endoplasmic reticulum. Additionally, the basolateral plasma membrane formed numerous interdigitating folds. Glycoconjugates with vicinal diol groupings were present predominantly in the secretory vesicles, the Golgi apparatus, the surface coat of the plasma membrane, and the majority of the intracellular membranes. With lectin cytochemistry, the secretory vesicles of the glandular cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose beta-N-acetyl-D-glucosamine, and sialic acid). Several sugars were distinctly prominent in the surface coat of the plasma membrane of the secretory cells. The cytochemical properties of the complex glycoconjugates found are discussed in relation to the specific functions of the glandular secretions. These glands may have an important role in not only thermoregulation but protection of the scrotal skin, a specific body region.

Elucidation of N-Glycosylation Sites on Human Platelet Proteins

Among known platelet proteins, a prominent and functionally important group is represented by glycoprotein isoforms. They account e.g. for secretory proteins and plasma membrane receptors including integrins and glycoprotein VI as well as intracellular components of cytosol and organelles including storage proteins (multimerin 1 etc.). Although many of those proteins have been studied for some time with regard to their function, little attention has been paid with respect to their glycosylation sites. Here we report the analysis of N-glycosylation sites of human platelet proteins. For the enrichment of glycopeptides, lectin affinity chromatography as well as chemical trapping of protein bound oligosaccharides was used. Therefore, concanavalin A was used for specific interaction with carbohydrate species along with periodic acid oxidation and hydrazide bead trapping of glycosylated proteins. Derivatization by peptide:N-glycosidase F yielded deglycosylated peptides, which provided the basis for the elucidation of proteins and their sites of modification. Using both methods in combination with nano-LC-ESI-MS/MS analysis 70 different glycosylation sites within 41 different proteins were identified. Comparison with the Swiss-Prot database established that the majority of these 70 sites have not been specifically determined by previous research projects. With this approach including hydrazide bead affinity trapping, the immunoglobulin receptor G6f, which is known to couple to the Ras-mitogen-activated protein kinase pathway in the immune system, was shown here for the first time to be present in human platelets.

Comprehensive two-dimensional normal-phase (adsorption)-reversed-phase liquid chromatography.

A comprehensive two-dimensional HPLC system has been developed. It is based on the use of a microbore silica column operated in normal-phase (adsorption) mode (NP) in the first dimension and a monolithic type C18 column operated in reversed-phase (RP) mode in the second dimension. The interface was a 10-port, 2-position valve equipped with two storage loops. The first column was operated at a flow rate of 20 microL/min in isocratic mode, while the monolithic column flow rate was 4 mL/min and was operated in gradient mode. The sample loops had a volume of 20 microL each, and the analysis time in the second dimension was 1 min. In this way, every fraction from the first dimension was transferred on-line to the second dimension switching the automated valve every minute. A photodiode array detector has been used after the secondary column. The use of normal- and reversed-phase mode in the two dimensions can be helpful in the separation of complex mixtures of a natural origin that contain uncharged molecules of comparable dimension, different in polarity and hydrophobicity. The use of a microbore column in the first dimension permits the injection of a small volume in the secondary column, making the transfer of incompatible solvents from the first to the second dimension possible. Since the mobile phase in the NP separation is always stronger than the mobile phase at the head of the secondary column operated in RP mode, the initial eluent strength is important in order to obtain an effective focusing of the sample. The use of a monolithic type column in the second dimension permits the performance of very fast analysis operating at higher flow rates without loss of resolution, due to a higher permeability and increased mass-transfer properties in comparison to conventional particulate columns. Due to the brief reconditioning time necessary for monolithic columns, repetitive gradients can be carried out, extending the field of application to mixtures that contain components with different polarities. The utility of the system has been demonstrated in the analysis of the oxygen heterocyclic fraction of cold-pressed lemon oil, made up of coumarins and psoralens. These components may contain hydroxyl, methoxyl, isopentenyl, isopentenyloxyl, and geranyloxyl groups and oxygen-containing modification of the terpenoid side-chain groups, such as epoxides or vicinal diol groups. The relative location of the components in the 2D plane varied in relation to their chemical structure and allowed positive peak identification. The UV spectra recorded with the photodiode array detector supplied additional information that was used for the characterization of the studied sample.

Ultracytochemical demonstration of glycoproteins in the canine knee synovium

By various ultracytochemical methods, glycoconjugates of the synoviocytes, the intercellular matrix and the wall of the small capillaries were studied in the synovial intimal tissues of the canine knee joint. Glycoconjugates with vicinal diol groups could be visualized in certain elements of the Golgi complex, lysosomes, vacuoles, the majority of intracellular cytomembranes, the surface coat of the plasma membrane and glycogen particles in type A cells. In type B cells, less-developed Golgi complexes, and fewer lysosomes and vacuoles were present in the cytoplasm than in that of type A cells. In contrast, a large number of cytoplasmic glycogen particles and abundant vicinal diol-containing groups in the surface coat of the plasma membrane became especially obvious in the B cells. Abundant neutral and acidic glycoproteins were observed in fibrous components in the intercellular matrix. In the small capillaries, strongly positive staining intensities for neutral and acidic glycoconjugates were observed in the basement membrane and perivascular connective tissue, as well as in the surface coat of the luminal plasma membrane of the endothelial cells, although to a somewhat weaker degree. Sialic acid, particularly, was notable in the surface coat of the latter cells. In addition, glycoproteins in the type A cells were shown by lectin ultracytochemistry to contain a variety of saccharide residues such as alpha-D-mannose, alpha-D-glucose, alpha-L-fucose, N-acetyl-beta-D-glucosamine, and N-acetyl-neuraminic acid, which were also found in the plasma membrane of the B cells. The properties of the glycoconjugates found are discussed in relation to the basic functions assigned to the synovial membrane of the canine knee joint.

RNA-sensitive N-isopropylacrylamide/vinylphenylboronic acid random copolymer

Random copolymers of N-isopropylacrylamide (NIPA) and 4-vinylphenylboronic acid (VPBA) were obtained by solution polymerization using 2,2′-azobisizobutyronitrile as the initiator in ethanol at 65 °C. NIPA-co-VPBA copolymer exhibited both temperature- and pH-sensitivity. Thermally reversible phase transitions were observed both in the acidic and alkaline pH region for the copolymers produced with different VPBA/NIPA feed ratios. The pH dependency of the lower critical solution temperature (LCST) was stronger for the copolymers produced with higher VPBA feed concentrations. RNA was selected as a model biomolecule having vicinal-diol and amino groups that were potentially reactive with the boronic acid groups of NIPA-co-VPBA copolymer. The effect of RNA concentration on the LCST of NIPA-co-VPBA copolymer was investigated in aqueous media at different pHs. Although no significant effect was observed at pH 4, 7 or 10.5, the LCST decreased linearly with increasing RNA concentration at a pH approximately equal to the pKa of boronic acid. This behavior was explained by considering the binding of RNA onto the copolymer chains to occur via two types of complex formation. For the formation of these complexes, the amino and vicinal-diol groups of RNA should react with the boronic acid groups of the copolymer in the tetrahedral anionic form. The results indicated that NIPA-co-VPBA copolymer could be utilized as a new reagent for the determination of RNA concentration in aqueous media. The proposed method was valid for the RNA concentration range of 0–4 g · mL−1. The schematical representation of the possible interactions between NIPA-co-VPBA copolymer and RNA. (A) A typical structure of single-stranded RNA. (B) Tetrahedral anionic form of boronic acid groups. (C) The interaction between the amino groups of the unpaired bases of RNA and the boronic acid groups of the copolymer. (D) Cyclic borate ester formation by the interaction between vicinal diol groups located at the 3′-end of RNA and boronic acid groups of the copolymer.

Histological and histochemical studies on the lingual, preglottal and laryngeal salivary glands of the Japanese quail (Coturnix coturnix japonica) at the post-hatching period.

The postnatal development and histochemistry of mucins of the lingual, preglottal and laryngeal glands in the quails were investigated by means of light microscopy using specific staining for complex carbohydrates. In this study, the tongues were taken from female and male quails from day 1 to day 60 after hatching. The salivary glands in quail's tongue comprised the lingual gland, with lateral and medial (paraentoglossal gland) portions that differ in morphology and histochemical staining, and the preglottal gland, with two lateral portions and one medial portion. The medial portion of the preglottal gland, which extended to the row of the laryngeal papillae on each side of the glottis, was described as the laryngeal gland. The salivary glands were present at hatching and their cells were functionally mature and secreted mucins. In quail of all ages, the histochemical reactions revealed that the cytoplasms of the secretory cells of the preglottal, laryngeal and paraentoglossal gland (medial portion of lingual gland) contained sialomucins and weakly sulphated epithelial mucins. Neutral mucins were absent in the paraentoglossal gland, while a small amount of neutral mucins was present in other glands. The mucins with vicinal diol groups, sialomucins and weakly sulphated epithelial mucins were mixed within the secretory cells of all the glands. All the histochemical reactions were restricted to the supranuclear regions of the secretory cells within the lateral portion of the lingual gland. In conclusion, the contents of mucins in the lingual, preglottal and laryngeal glands varied between different age groups, however, no differences in the glands' histochemistry between male and female quails were observed.

Conversion of Steroidal Vicinal Diols to the Corresponding Olefinic Compounds

The wide applicability of two-step conversion of a vicinal diol group to carbon-carbon double bond developed by Corey and Winter was examined for various steroids with vicinal diol (s). By refluxing with triethyl phosphite, cyclic thionocarbonates derived from the vicinal diol steroids were converted to the corresponding olefinic steroids in high yields. Using this two-step conversion as a key step, brassinosteroid-related compounds, (22R, 23R, 24S) - and (22S, 23S, 24S) -2α, 3α, 22, 23-diepoxy-B-homo-7-oxa-5α-stigmastan-6-ones produced more efficiently than reported to date.

Adsorption Mechanism of Boric Acid on Chitosan Resin Modified by Saccharides.

This study aims to develop an environmentally-friendly resin for boron recovery. To this end, the adsorption characteristics of boron on chitosan resins chemically modified by saccharides are investigated for the purpose of the removal of boron from a boron mine and the desulfurizing equipment in coal-fired steam power stations, and compared with those of a commercial resin (Duolite ES371). First, chitosan derivatives incorporating saccharides were synthesized by reductive N-alkylation, and the products were crosslinked with ethylene glycol diglycidil ether. The resulting products (SMC resins) were found to exhibit dissolubility in acidic and basic solutions.From the adsorption experiment on the resins (SMC and Duolite resins), it is found that the adsorption mechanism is a complex formation between boron which exists as boric acid or borate in an aqueous solution and the vicinal diol groups of the branched saccharide. The apparent adsorption equilibrium constants of boric acid-diol complex and borate-diol salt complex are determined. The adsorption isotherms of boron correlate well with the Langmuir equation, and the order of the saturated adsorption capacity of boron on SMC resins corresponds to that of the degree of substitution on SMC resins.

Study of bimolecular interactions by molecular modeling and surface acoustic wave device

AbstractA film containing vicinal diol groups has been formed on the quartz surface of a surface acoustic wave sensor through a silanization reaction with 3‐glycidoxypropyltrimethoxysilane. The interactive selectivity of the silane surface for adsorption of several vapor analytes was measured using a gas chromatograph‐acoustic wave device combination. Much larger responses are obtained for compounds containing a nitrofunctional group. Computational chemistry is employed to calculate interaction energies for purported hydrogen‐bond complexes between analyte molecules and ethylene glycol, an analogue of the surface silane species. The results of these calculations are compared to the experimental sensor responses.

ChemInform Abstract: Synthesis of Steroids Containing a Vicinal Diol Group in the Side Chain via Formation of Isoxazoline Intermediates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of steroids containing a vicinal diol group in the side chain via isoxazoline intermediates

A sequence of conversions including 1,3-dipolar cycloaddition of nitrile oxides to steroid 22-enes and modification of the isoxazolines obtained by hydroxylation to the 4′ position and splitting of the heterocycle leads to steroids with a polyfunctional open chain, 22,23-dihydroxy 24-ketones.

Capillary electrophoretic chiral resolution of vicinal diols by complexation with borate and cyclodextrin: Comparative studies on different cyclodextrin derivatives

Capillary electrophoretic enantioseparation of compounds containing vicinal diol groups have been investigated using different β-cyclodextrin (CD) derivatives and borate as a background electrolyte. Both native β-CD and several β-CD derivatives are examined. Chiral recognition is attributed to both enantioselective inclusion of the analyte into the chiral cavity of the CD and complexation with borate. The influence of concentration of the chiral selector, pH, and organic modifiers on the resolution was studied. Four diols were baseline separated. Chirality 9:153–156, 1997. © 1997 Wiley-Liss, Inc.

Boron Removal by Polymer-Assisted Ultrafiltration

Abstract Boron contamination of natural waters is a widespread environmental problem which lacks a cost-effective solution. Polymer-assisted ultrafiltration is a method of boron removal that is compatible with other water-treatment processes. This boron removal technique exploits the pH-dependent complexation between boric acid and a macromolecule containing vicinal diol groups to prevent boric acid from passing through an ultrafiltration membrane. The concentration of boron in treated water was reduced from 10.5 ppm to less than 2 ppm through ultrafiltration of an aqueous solution containing boric acid and a polymer synthesized by grafting N-methyl-D-glucamine (NMG) onto poly(epichlorohydrin). The NMG groups, when tethered to the polymer, exhibited stronger affinity for boron than expected from equilibria between NMG and boric acid.

Murihexocins A and B, two novel mono-THF acetogenins with six hydroxyls, from Annona muricata (Annonaceae)

Two novel bioactive acetogenins, murihexocins A (1) and B (2), were isolated from the leaves of the sour sop tree, Annona muricata (Annonaceae). 1 and 2 are C-35 mono-tetrahydrofuran (THF) acetogenins having six hydroxyls, and their structures have been elucidated by spectroscopic analyses and derivations. No Annonaceous acetogenins having six hydroxyls or with two vicinal diol groups have been reported previously. 1 and 2 showed significant inhibitory effects among six human tumor cell lines with interesting selectivities to the prostate (PC-3) and pancreatic (PACA-2) cell lines.

Murihexocins A and B, two novel mono-THF acetogenins with six hydroxyls, from Annona muricata (Annonaceae)

Two novel bioactive acetogenins, murihexocins A ( 1) and B ( 2), were isolated from the leaves of the sour sop tree, Annona muricata (Annonaceae). 1 and 2 are C-35 mono-tetrahydrofuran (THF) acetogenins having six hydroxyls, and their structures have been elucidated by spectroscopic analyses and derivations. No Annonaceous acetogenins having six hydroxyls or with two vicinal diol groups have been reported previously. 1 and 2 showed significant inhibitory effects among six human tumor cell lines with interesting selectivities to the prostate (PC-3) and pancreatic (PACA-2) cell lines.

Polyhydroxy fatty acids and their derivatives from plant oils

AbstractA novel process for the industrial production of hydroxylated fatty acids involves epoxidation of plant oils and their derivatives, followed by catalytic epoxy ring opening in the presence of water or other hydrogen donors, such as alcohols, diols, and amines. Depending on the starting material, epoxidation followed by opening of the oxirane ring leads to fatty acids that contain vicinal diol groups or to other substituted hydroxylated fatty acid derivatives. As an example for the preparation of a substituted hydroxylated fatty acid derivative, the reaction of epoxidized rapeseed oil with monobutylamine as hydrogen donor is described. Apart from the intended formation of hydroxyl groups with vicinal aminoalkyl groups, partial aminolysis of the ester compound was also observed. Another example describes the reaction of epoxidized rapeseed oil with different molar proportions of 1,4‐butanediol as hydrogen donor. Depending on the molar proportion of the hydrogen donor, interesterification, or intermolecular ether formation were observed as side reactions. The properties of various technical hydroxylated fatty acids and their derivatives, prepared according to this novel process, are given, and potential applications of these products are suggested.

A potential vaccine for cocaine abuse prophyslaxis?

O. Bagasra, L.J. Forman, A. Howeedy, and P.A. Whittle recently conveyed the preparation of a cocaine immunogen that is a potential vaccine for cocaine abuse prophylaxis (Immunopharmacology: 1992, 23, 173–179). These investigators claim to have prepared a cocaine immunogen via reaction of cocaine with sodium metaperiodate followed by carrier protein, and to have generated anti-cocaine antibodies by using this immunogen. Periodate is used to conjugate haptens that contain a vicinal diol (or similar) group to carrier proteins and would not be expected to couple cocaine to protein. The authors of the above publication reported titres for antibodies generated by using their immunogen, but did not describe competitive inhibition of antibody binding by cocaine and did not report the specificity characteristics of their antibodies. The present author is not convinced by the claims made by Bagasra et al.

Partial purification and characterization of a circulating hypertensive factor in spontaneously hypertensive rats.

Parabiosis and cross-circulation experiments with spontaneously hypertensive and normotensive rats gave indications for a previously unidentified circulating hypertensive agent. In this study, plasma from normotensive and hypertensive rats was fractionated and the vasopressor action of the corresponding fractions was measured in the isolated perfused rat kidney. One of three vasoactive fractions obtained by gel filtration (Biol-Gel P2) from hypertensive rats showed a significantly higher activity (increase in perfusion pressure by 1502.9 +/- 438.9 Pa) than that from normotensive rats (increase in perfusion pressure by 505.4 +/- 186.2 Pa, P < 0.01). Further chromatographic separations of this fraction revealed that the hypertensive factor is hydrophilic and has no ionic groups or vicinal diol groups. The molecular mass was estimated by dialysis and the matrix-assisted laser desorption/ionization mass spectrometry to be in the range of 1 kDa. The vasopressor is heat resistant and not degradable with trypsin or carboxypeptidase Y. The vasopressor action was not inhibited with the angiotensin-II-receptor antagonist saralasin, the alpha-receptor antagonist phentolamine, the thromboxane-receptor antagonist carbocyclic thromboxane A2 or the serotonin antagonist ketanserin. The results confirm the existence of a vasopressor factor in the plasma of hypertensive rats and, in a lower concentration, of normotensive rats, which is possibly related to the pathogenesis of essential hypertension. The chromatographic behavior suggests that this factor is different from the parathyroid hypertensive factor described recently.