Acid Hydrolysis Products Research Articles

Lipolysis effects of lancemaside A and aglycon from Codonopsis lanceolata water extract in primary cultured adipocytes from obese rat fed high calorie high fat diet

We examined the effects of Lancemaside A and aglycon, its acid hydrolysis product from Lancemaside A, isolated from Codonopsis lanceolata water extract on triglyceride and free fatty acid in primary cultured adipocytes from obese rats fed high calorie high fat diet. Animals (6-week old male Sprague-Dawley rats) were administered a 60% high-fat diet for 6 weeks and adipocyte isolated from apididymal fat [1]. Adipocytes cultured with samples for 4 day. Lipids were extracted by Folch method [2]. Lancemaside A and aglycon significantly reduced in lipid droplets, TG and FFA in a concentration-dependent manner. These data suggest that Lancemaside A and aglycon were active compounds of Codonopsis lanceolata, and these samples improves lipid dysregulation. It could be widely utilized in the therapeutic and functional food for obesity patients.

The effect of lufenuron, a chitin synthesis inhibitor, on oogenesis of Rhodnius prolixus

The effects of lufenuron, a chitin synthesis inhibitor, on oogenesis of Rhodnius prolixus were evaluated. Lufenuron-treated females lay eggs that are pink, but change color with time, acquiring a gray color. The eggs are abnormal in shape and become dehydrated. The percentage of eggs that hatch is decreased compared with the eggs from non-treated females. Digestion of ovaries with KOH yielded an insoluble white material, which was identified as chitin based on infrared and proton NMR spectral analyses along with standard commercial chitin. Glucosamine was detected by HPLC as the major product of acid hydrolysis of the KOH-insoluble material prepared from the ovary. Furthermore, presence of chitin in ovary was confirmed through fluorescent microscopy technique using a wheat germ agglutinin probe and by re-treatment with Streptomyces griseus chitinase that resulted in reduction of chitin-derived fluorescence. Micrographs of ovaries, from animals treated with lufenuron, showed some space between the follicular epithelium and the oocyte membrane. The in vivo incorporation of radioactive N-acetylglucosamine into chitin was inhibited by the presence of lufenuron. These data suggest that chitin present in ovaries of R. prolixus is an important component of the eggs and is involved in oogenesis. Exposure to lufenuron reduces the size of oocytes, number of chorionated oocytes, and also the incorporation of N-acetylglucosamine into chitin in the ovaries. In addition, lufenuron-induced oosorption, decreased the number of eggs laid, modified egg shape and color and reduced the viability of the eggs. Therefore, chitin or chitin-like component of ovaries may be considered as a new target for controlling R. prolixus populations.

Polylactide Stereocomplexation Leads to Higher Hydrolytic Stability but More Acidic Hydrolysis Product Pattern

Poly-l-lactide/poly-d-lactide (PLLA/PDLA) stereocomplex had much higher hydrolytic stability compared to plain PLLA, but at the same time shorter and more acidic degradation products were formed. Both materials were subjected to hydrolytic degradation in water and in phosphate buffer at 37 and 60 degrees C, and the degradation processes were monitored by following mass loss, water uptake, thermal properties, surface changes, and pH of the aging medium. The degradation product patterns were determined by electrospray ionization-mass spectrometry (ESI-MS). The high crystallinity and strong secondary interactions in the stereocomplex prevented water uptake and resulted in lower mass loss and degradation rate. However, somewhat surprisingly, the pH of the aging medium decreased much faster in the case of PLLA/PDLA stereocomplex. In accordance, the ESI-MS results showed that hydrolysis of PLLA/PDLA resulted in shorter and more acidic degradation products. This could be explained by the increased intermolecular crystallization due to stereocomplexation, which results in an increased number of tie chains. Because mainly these short tie chains are susceptible to hydrolysis this leads to formation of shorter oligomers compared to hydrolysis of regular PLLA.

Stability-Indicating HPLC Method for the Determination of Impurities in Meprobamate with Refractive Index Detection

The purpose of this study is to develop and validate a simple, sensitive, and robust high-performance liquid chromagraphic (HPLC) method for the determination of impurities ca. 2-methyl-2-propyl-1,3-propane diol (MP0) and 2-hydroxymethyl-2-methyl pentyl carbamate (MP1) in meprobamate (MEP) drug substance with refractive index (RI) detection. This method utilizes a Zorbax Eclipse XDB C(18) HPLC column, a mobile phase of 80:20 (v/v) 10 mM KH(2)PO(4),-acetonitrile, respectively. The stability-indicating capability of the method has been established by performing stress studies under acidic, basic, oxidation, light, humidity, and thermal conditions. The major degradation products of acid and base hydrolysis are identified as MP0 and MP1. The recovery data obtained for impurities are between 96.0-109.8%. The detection and quantitation limits of this method ranges from 0.009 to 0.017 mg/mL and 0.029 to 0.055 mg/mL, respectively. The relative standard deviation (RSD) for the area at QL is less than 6.1%. Good linearity (r(2) > 0.99) and precision (RSD < 2.2%) have been obtained for MEP, MP0, and MP1. This method has been applied successfully to determine the content of impurities in MEP bulk drug.

Characterization of novel hydrolysis products of carbapenems by electrospray ionization mass spectrometry

Carbapenems, including meropenem and imipenem, exhibit low stability against acid or base reagents. The fragmentation behavior of meropenem and its acid hydrolysis products was investigated by Fourier transform ion cyclotron resonance electrospray ionization tandem mass spectrometry and ion trap tandem multi-stage mass spectrometry in both positive and negative ion mode. Only one neutral loss of CO(2) was observed from the precursor ion to the MS(4) product ions for the acid hydrolysis product and this behavior did not correspond to that expected for the previously accepted 1-pyrroline or 2-pyrroline structure with two carbonyl acid units. The unknown product was then proposed to be 2-(4-(5-(dimethylcarbamoyl)pyrrolidin-3-ylthio)-5-imino-3-methyl-6-oxotetrahydro-2H-pyran-2-yl)-3-hydroxybutanoic acid on the basis of the multi-stage mass spectrometric and accurate mass data. A similar acid hydrolysis product of imipenem was also identified by mass spectrometry, confirming that these carbapenems had the same acid hydrolysis behavior. The proposed structures were further confirmed by NMR experiments.

Hippuric acid and benzoic acid inhibition of urine derived N2O emissions from soil

AbstractAtmospheric concentrations of the greenhouse gas nitrous oxide (N2O) have continued to rise since the advent of the industrial era, largely because of the increase in agricultural land use. The urine deposited by grazing ruminant animals is a major global source of agricultural N2O. With the first commitment period for reducing greenhouse gas emissions under the Kyoto Protocol now underway, mitigation options for ruminant urine N2O emissions are urgently needed. Recent studies showed that increasing the urinary concentration of the minor urine constituent hippuric acid resulted in reduced emissions of N2O from a sandy soil treated with synthetic bovine urine, due to a reduction in denitrification. A similar effect was seen when benzoic acid, a product of hippuric acid hydrolysis, was used. This current laboratory experiment aimed to investigate these effects using real cow urine for the first time. Increased concentrations of hippuric acid or benzoic acid in the urine led to reduction of N2O emissions by 65% (from 17% to &lt;6% N applied), with no difference between the two acid treatments. Ammonia volatilization did not increase significantly with increased hippuric acid or benzoic acid concentrations in the urine applied. Therefore, there was a net reduction in gaseous N loss from the soil with higher urinary concentrations of both hippuric acid and benzoic acid. The results show that elevating hippuric acid in the urine had a marked negative effect on both nitrification and denitrification rates and on subsequent N2O fluxes. This study indicates the potential for developing a novel mitigation strategy based on manipulation of urine composition through ruminant diet.

Cycloartane glycosides from Euphorbia glareosa

We have previously reported the isolation from various species of Euphorbia growing in Georgia of flavonoids [1] and polyphenols [2]. We also found that all studied species contained in addition to the aforementioned classes of compounds triterpene glycosides of the cycloartane series. Herein we communicate results from a study of the structure of cycloartane glycosides isolated from E. glareosa (Euphorbiaceae). Triterpene glycosides were obtained by exhaustive extraction (2 × 5 L) of ground air-dried roots (0.8 kg) at room temperature. The MeOH extract was evaporated and worked up by the literature method [3] to afford triterpenoids (20.5 g total) that were separated over a column of silica gel (L 40/100, Czech Rep.) using CHCl3:CH3OH (1, 15:1), CHCl3:CH3OH:H2O (2, 70:23:4), C6H6:EtOAc (3, 2:1 and 1:1), and CHCl3:C6H14:EtOAc (4, 1:1:1) [3]. We isolated eight compounds designated in order of increasing polarity as 1–8. Compounds 1 and 2 were the genins cyclosiversigenin and asgenin; the others, their glycosides. Compound 1, cyclosiversigenin, C30H50O5 (cycloastragenol, astramembrangenin [4]), yield 0.036% (here and henceforth of the weight of air-dried raw material), mp 238–240°C, [ ] α D 20 +50.4° (c 2.0, MeOH). IR spectrum (KBr, νmax, cm −1): 3500–3350 (OH), 3040, 1760, 1750, 1260–1250. PMR spectrum (Py-d5, δ, ppm, J/Hz, 0 = HMDS): 4.90 (1H, q, J = 7.0, H-16), 3.78 (1H, br.q, H-24), 3.57 (2H, m, H-3, H-6), 0.51 (d, J = 4.0) and 0.23 (br.s, 2H-19); CH3 groups 1.76, 1.46, 1.35, 1.25, 1.21, 1.18, 0.92 [3]. Compound 2, cycloasgenin, C30H48O6, yield 0.011%, mp 234–235°C, [ ] α D 20 +130.4° (c 0.8, MeHO). IR spectrum (KBr, νmax, cm −1): 3450–3350 (OH), 3060 (cyclopropane CH2), 1706–1695 (C=O). PMR spectrum (Py-d5, δ, ppm, J/Hz, 0 = HMDS): 4.92 (1H, q, J = 7.3, H-16), 4.20 (1H, dd, J = 9.8, 2.5, H-11), 3.72 (1H, m, H-6), 1.64 (d, J = 4.0) and 0.46 (br.s, 2H-19), 3.75 (1H, dd, J = 8.8, 5.6, H-24), CH3 groups 1.70, 1.44, 1.41, 1.39. 1.21, 1.16, 0.84 [3]. A study of the acid hydrolysis products of the glycosides [5] showed that they all contained cyclosiversigenin as the genin. The structures of the carbohydrate parts of the glycosides were established using chemical transformations (Hakomori methylation [6] with subsequent methanolysis and GC of the sugars) and IR and PMR spectral data. Compound 3, cyclosiversigenin 3,6-O-β-D-dixylopyranoside, C40H66O13, 0.008%, mp 218–221°C (MeOH), [ ] α D 20 +29.0° (c 0.71, MeOH). IR spectrum (KBr, νmax, cm −1): 3200-3600 (OH), 3040–3060 (cyclopropane CH2). PMR spectrum (Py-d5, δ, ppm, J/Hz): 4.56 and 4.42 (d, J = 7.2, H′ and H′′), 1.70, 1.44, 1.25, 0.95 (eath 3H, s, CH3), 1.16 (9H, s, CH3 × 3), 0.46 (1H, br.s, Ha-19) [7, 8]. Compound 4, cyclosiversigenin 3-O-[β-D-xylopyranoside-(2′-O-acetyl)]-6-O-β-D-xylopyranoside, C42H68O14, 0.03%, mp 253–254°C (MeOH), [ ] α D 20 +31° (c 0.90, MeOH). IR spectrum (KBr, νmax, cm −1): 3360–3500 (OH), 1750, 1260 (ester). PMR spectrum (Py-d5, δ, ppm, J/Hz): 5.32 (1H, br.t, H-2′), 4.68 (1H, d, J = 6.2) and 4.55 (1H, d, J = 7.5); anomeric protons of two xyloses: 1.90 (3H, s, CH3CO), 1.52, 1.41, 1.26, 1.18, 1.15, 1.07, 0.95, (each 3H, s, CH3), 0.45 (1H, d, J = 4.0, Ha-19) [8, 9]. Compound 5, cyclosiversigenin 3-O-β-D-xylopyranoside-6-O-β-D-glucopyranoside, C41H68O14, 0.009%, mp 247– 249°C (MeOH), [ ] α D 20 +37.0° (c 0.5, MeOH). IR spectrum (KBr, νmax, cm −1): 3300–3500 (OH), 3040 (cyclopropane CH2). PMR spectrum (Py-d5, δ, ppm, J/Hz): 4.78 (1H, d, J = 7.8, H-1′′), 4.52 (1H, d, J = 7.4, H-1′), 1.82, 1.40, 1.26, 0.80, (each 3H, s, CH3), 1.16 (9H, s, CH3), 0.44 (1H, d, J = 3.9, Ha-19) [10].

Genome Mining in Streptomyces avermitilis: A Biochemical Baeyer−Villiger Reaction and Discovery of a New Branch of the Pentalenolactone Family Tree

Incubation of 1-deoxy-11-oxopentalenic acid (12) with recombinant PtlE protein from Streptomyces avermitilis in the presence of NADPH and catalytic FAD gave the Baeyer-Villiger oxidation product, the previously unknown compound neopentalenolactone D (13), representing a new branch of the pentalenolactone biosynthetic pathway. The structure and stereochemistry of the derived neopentalenolactone D methyl ester (13-Me) were fully assigned by a combination of GC-MS and NMR analysis and confirmed by X-ray crystallography. Neopentalenolactone D (13) was also isolated from engineered cultures of S. avermitilis from which the ptlD gene within the 13.4-kb (neo)-ptl biosynthetic gene cluster had been deleted. The DeltaptlEDeltaptlD double deletion mutant accumulated 12, the substrate for the ptlE gene product, while the corresponding single DeltaptlE mutant produced 12 as well as the related oxidation products 14 and 15. Engineered strains of S. avermitilis, SUKA5 and pKU462::ermRp-ptl cluster, harboring the complete (neo)ptl cluster produced the oxidized lactone 18 and the closely related seco acid hydrolysis products 16 and 17.

Degrees of polymerization (DP) and DP distribution of dilute acid-hydrolyzed products of alkali-treated native and regenerated celluloses

Three groups of cellulose II samples, 20% NaOH-treated native celluloses (M-native celluloses), commercial regenerated celluloses and those treated with 20% NaOH (M-regenerated celluloses), were subjected to dilute acid hydrolysis at 105 °C to obtain so-called leveling-off degrees of polymerization (LODP). Molecular mass parameters of the acid-hydrolyzed products were analyzed by SEC-MALLS using 1% LiCl/DMAc as an eluent. The LODP values were in the order of M-native celluloses ≅ M-regenerated celluloses > regenerated celluloses. The LODP values of M-regenerated celluloses are 1.5–1.7 times as much as those of the regenerated celluloses; the cellulose II crystallites in regenerated celluloses increase in size to the longitudinal direction by the alkali treatment and the successive acid hydrolysis at 105 °C. This increase in the longitudinal crystal sizes might primarily occur during acid hydrolysis. All the acid-hydrolyzed products had bimodal SEC elution patterns, i.e. the predominant high-molecular-mass and minor low-molecular-mass components, the latter of which corresponded to DP 20.

Kinetic and J-Resolved Statistical Total Correlation NMR Spectroscopy Approaches to Structural Information Recovery in Complex Reacting Mixtures: Application to Acyl Glucuronide Intramolecular Transacylation Reactions

We demonstrate here a new variant on a statistical spectroscopic method for recovering structural information on unstable intermediates formed in reaction mixtures. We exemplify this approach with respect to the internal acyl migration reactions of 1-beta-O-acyl glucuronides (AGs), which rearrange at neutral or slightly alkaline pH on a minute to hour time scale to yield a series of positional glucuronide ring isomers and alpha/beta anomers from the 1-beta (starting material), i.e. 2-beta, 2-alpha, 1-alpha, 3-beta, 3-alpha, and 4-beta, 4-alpha isomers together with the aglycon and alpha- and beta-glucuronic acid hydrolysis products. Multiple sequential 800 MHz cryoprobe (1)H NMR spectra (1D and 2D J-resolved, JRES) were collected on a 5.1 mM solution of a synthetic model drug glucuronide, 1-beta-O-acyl (S)-alpha-methyl phenylacetyl glucuronide (MPG) in 0.1 M sodium phosphate buffer in D2O at pD 7.4 over 18 h to monitor the reaction which leads to the formation of the eight positional isomers and hydrolysis products. As the reaction proceeds and new isomers form, the NMR signal intensities vary accordingly allowing the application of a novel kinetic variant on statistical total correlation spectroscopy (K-STOCSY) method to recover the connectivities between proton signals on the same reacting molecule based on their intensity covariance through time. We performed K-STOCSY analysis on both the standard 1D NMR spectra and the skyline projected singlets of the (1)H-(1)H JRES NMR spectra through time, i.e. the K-JRES-STOCSY experimental variant, which increases the effective spectral dispersion and is ideally suited for the analysis of heavily overlapped spin systems. High statistical correlations were observed between mutarotated alpha- and beta-anomers of individual positional isomers, as well as directly acyl migrated products and anticorrelation observed between signals from compounds that were being depleted as others increased, e.g. between the 1-beta and 2-alpha/2-beta isomers. This statistical kinetic approach enabled the recovery of structural connectivity information on all isomers allowing unequivocal resonance assignment, and this approach to spectroscopic information recovery has wider potential uses in the study of reactions that occur on the second-to-minute time scale in conditions where multiple sequential NMR spectra can be collected. JRES-STOCSY is also of potential use as a method for recovering spectroscopic information in highly overlapped NMR signals and spin systems in other types of complex mixture analysis.

Isolation of Pyranocoumarins from Angelica Gigas

A mixture of diastereomers of the coumarin glycoside 3′- O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (1), along with six known pyranocoumarins, columbianoside (4), marmesin (5), 3′-hydroxy-3′,4′-dihydroxanthyletin (6), decursin (7), decursinol angelate (8), and isoimperatorin (9), were isolated from the roots of Angelica gigas Nakai. The racemic compound 1 was successfully separated by preparative HPLC to obtain a new isomer 3′( S)- O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (2), and a known isomer 3′( R)- O-β-D-glucopyranosyl-3′,4′-dihydroxanthyletin (3). The absolute configuration of compounds 2 and 3 was determined by comparison of optical rotation and NMR data of their acid hydrolysis products.

New antioxidant phytopreparation from Rumex thyrsiflorus roots. III

We identified in the phytopreparation caffeic, gallic, and p-hydroxybenzoic acids; phloroglucinol, hydroquinone, pyrogallol, quercetin, myricetin, rutin, isorhamnetin, isorhamnetin-3-O-rutinoside, myricetin-3-O-rhamnoside, (+)-catechin, (-)-epicatechin gallate, chrysophanol, emodin, and physcion and their glycosides; one of which was 5-methoxyphyscion 4-O-glucoside, a new compound for sorrels. The structure of this compound was established using UV, IR, and PMR spectra; products of total acid hydrolysis, and comparison with the literature [3, 11]. The antioxidant activity of the phytopreparation was studied at the Scientific-Research Center for Chemistry (Pakistan) by testing with DPPH (1,1-diphenyl-2-propylhydrasil radical) as before [12]. It was slightly more active (95%) than the standard propylgallate (94.12%). The phytopreparation can be recommended for use. The roots of R. thyrsiflorus F. can be used as raw material for its production. This expands the variety of natural antioxidants.

Spectrophotometric determination of some cephalosporin antibiotics using Prussian blue reaction

A simple, sensitive and accurate spectrophotometric method of analysis of ceftriaxone, cefotaxime and cefuroxime in pharmaceutical dosage forms has been developed and validated. The method is based on the formation of Prussian Blue (PB) complex. The reaction between the acidic hydrolysis product of the antibiotics (T = 70 � C) with the mixture of Fe 3+ and hexacyanoferate (III) ions was evaluated for the spectrophotometric determination of the antibiotics. The maximum absorbance of the coloured complex occurred at � = 700 nm and the molar absorptivity is 3.0 x 10 4 l.mol -1 cm -1 . Reaction conditions have been optimized to obtain PB complex of high sensitivity and longer stability. Under optimum conditions the absorbance of the PB complex were found to increase linearly with increase in concentrations of ceftriaxone, cefotaxime and cefuroxime, which corroborated with the correlation coefficient values. The linear range of the calibration graph was 2 - 20 �g/ml for ceftriaxone and cefotaxime and 2 - 18 �g/ml for cefuroxine. The proposed method was successfully applied to the determination of the selected antibiotics in bulk drugs and pharmaceutical formulations and the results obtained agree well with the labeled contents.

Identification of hexose hydrolysis products in metabolic flux analytes: A case study of levulinic acid in plant protein hydrolysate

Biosynthetically directed fractional 13C labeling, a popular methodology of metabolic flux analysis, involves culture on a mixture of 13C and 12C substrates and preparation a ‘metabolic flux analyte’ (typically protein hydrolysate) from the biomass. Metabolic flux analytes prepared from complex eukaryotes may contain additional compounds than those prepared from microorganisms. We report the presence of such compounds (hexose hydrolysis products) in a plant metabolic flux analyte (acid hydrolyzed protein from soybean embryos). We designed NMR experiments to systematically identify these compounds, and found that they were levulinic acid (LVA; major) and hydroxyacetone (HyA; minor). These acid hydrolysis products of hexoses (glucose and mannose) were generated during acid hydrolysis of glycosylating sugars (glucosamine and mannose) associated with soybean embryo protein. Analysis of LVA by two-dimensional [ 13C, 1H] NMR and measurement of its J-coupling constants revealed long-range coupling between atoms C3 and C5, which enables LVA to provide more isotopomer information than its precursor hexose. Furthermore, we found that LVA and HyA preserve the isotopomeric composition of the metabolic hexose from which they are derived. An important consequence of these results is that comparison of LVA and HyA isotopomers from two separate metabolic flux analytes (protein hydrolysate and starch hydrolysate) from the same plant tissue can distinguish between parallel glycolysis and pentose phosphate pathways in different subcellular compartments.

Glycopeptide Antitumor Antibiotic Zorbamycin from Streptomyces flavoviridis ATCC 21892: Strain Improvement and Structure Elucidation

Zorbamycin (1, ZBM) is a glycopeptide antitumor antibiotic first reported in 1971. The partial structures of 1 were speculated on the basis of its acid hydrolysis products, but the structure of the intact molecule has never been established. The low titer of 1 from the wild-type strain, combined with its acid-instability, has so far hampered its isolation. By random mutagenesis of Streptomyces flavoviridis ATCC21892, a wild-type producer of 1, with UV irradiation, two high-producing strains of 1, S. flavoviridis SB9000 and SB9001, were isolated. Under the optimized fermentation conditions, these two strains produced about 10 mg/L of 1, which was about 10-fold higher than the wild-type ATCC21892 strain, as estimated by HPLC analysis. Finally, 1 was isolated as both a 1-Cu complex and Cu-free molecule, and the intact structure of 1 was established on the basis of a combination of mass spectrometry and 1H and 13C NMR spectroscopic analyses.

Mode of action of glycoside hydrolase family 5 glucuronoxylan xylanohydrolase from Erwinia chrysanthemi

The mode of action of xylanase A from a phytopathogenic bacterium, Erwinia chrysanthemi, classified in glycoside hydrolase family 5, was investigated on xylooligosaccharides and polysaccharides using TLC, MALDI-TOF MS and enzyme treatment with exoglycosidases. The hydrolytic action of xylanase A was found to be absolutely dependent on the presence of 4-O-methyl-D-glucuronosyl (MeGlcA) side residues in both oligosaccharides and polysaccharides. Neutral linear beta-1,4-xylooligosaccharides and esterified aldouronic acids were resistant towards enzymatic action. Aldouronic acids of the structure MeGlcA(3)Xyl(3) (aldotetraouronic acid), MeGlcA(3)Xyl(4) (aldopentaouronic acid) and MeGlcA(3)Xyl(5) (aldohexaouronic acid) were cleaved with the enzyme to give xylose from the reducing end and products shorter by one xylopyranosyl residue: MeGlcA(2)Xyl(2), MeGlcA(2)Xyl(3) and MeGlcA(2)Xyl(4). As a rule, the enzyme attacked the second glycosidic linkage following the MeGlcA branch towards the reducing end. Depending on the distribution of MeGlcA residues on the glucuronoxylan main chain, the enzyme generated series of shorter and longer aldouronic acids of backbone polymerization degree 3-14, in which the MeGlcA is linked exclusively to the second xylopyranosyl residue from the reducing end. Upon incubation with beta-xylosidase, all acidic hydrolysis products of acidic oligosaccharides and hardwood glucuronoxylans were converted to aldotriouronic acid, MeGlcA(2)Xyl(2). In agreement with this mode of action, xylose and unsubstituted oligosaccharides were essentially absent in the hydrolysates. The E. chrysanthemi xylanase A thus appears to be an excellent biocatalyst for the production of large acidic oligosaccharides from glucuronoxylans as well as an invaluable tool for determination of the distribution of MeGlcA residues along the main chain of this major plant hemicellulose.

Polysaccharide and lipid composition of the brown seaweed Laminaria gurjanovae

Polysaccharide and lipid composition of the Pacific brown seaweed Laminaria gurjanovae is determined. Alginic acid is shown to be the main polysaccharide of its biomass (about 28%); it consists of mannuronic and guluronic acid residues at a ratio of 3 : 1. The yield of water-soluble polymannuronic acid is low and does not exceed 1.1% of dry biomass. High laminaran content (about 22%) is found, whereas the yield of fucoidan is no more than 3.6%. Laminaran consists of two fractions, soluble and insoluble in cold water, their ratio is 2.5 : 1. Practically, insoluble laminaran is a linear 1,3-beta-D-glucan, and the soluble fraction was shown to be 1,3;1,6- 3-D-glucan. The oligosaccharide products of desulfation or partial acidic hydrolysis of fucoidan were studied by MALDI TOF MS; they were found to be fuco- and galactooligosaccharides. The fucoidan is suggested to be a highly sulfated partially acetylated galactofucan (Fuc/Gal is -1 : 1). The main lipid components of the dried L. gurjanovae are neutral lipids and glyceroglycolipids, whereas phospholipids are found in minor amounts. The main fatty acid components of lipids are 14 : 0, 16 : 0, 16 : 1 n-7, 18 : 1 n-7, and 18 : 2 n-6 acids.

Direct detection method of oligosaccharides by high‐performance liquid chromatography with charged aerosol detection

A simple and rapid detection method of oligosaccharides using high-performance liquid chromatography with a charged aerosol detection (HPLC-CAD) was studied. The direct detection of a sialylglycopeptide (SGP) derived from egg yolk was accomplished by HPLC-CAD using an amido-silica column, and its limit of detection was 0.40 pmol [signal-to-noise ratio (S/N) = 3]. The sensitivity of this method was lower than that of the fluorescence detection; however, the method showed approximately 5 times higher sensitivity than that using the conventional UV absorbance detection. Furthermore, this method was used for the analysis of the acid hydrolysis products of SGP. Monosialo- and asialo-oligosaccharides as well as free sialic acid were detected without using fluorescent derivatization. These results indicate that the present method is a new tool for the analysis of oligosaccharides.

Stability of cabergoline in fox baits in laboratory and field conditions

Cabergoline is a potent inhibitor of prolactin release and a potential fertility control agent for foxes. To understand how cabergoline could behave in baits deployed for fox control, we conducted laboratory and field trials to investigate the stability of cabergoline when (1) in solution, (2) injected into a bait (deep-fried liver and Foxoff®) and (3) exposed to a range of environmental conditions, including burial. Cabergoline, dissolved in a 1% acetic acid solution, and its carboxylic acid hydrolysis product can be assayed using high-performance liquid chromatography. When stored at 4°C and at room temperature, cabergoline in solution was stable for up to 36 days. When stored under cool (≤15°C), dry conditions, cabergoline (800 µg) in commercial Foxoff® and deep-fried ox-liver baits was stable for 28 and 7 days, respectively; stability was reduced by increases in temperature (tested up to 40°C) and humidity. Recovery of cabergoline from buried baits exposed to a range of field conditions decreased rapidly in the first week, but after 56 days remained detectable at levels of 6–22% of the injected amounts. This study has important implications for baiting campaigns that use cabergoline for fox control.

N 2O 5 hydrolysis on the components of mineral dust and sea salt aerosol: Comparison study in an environmental aerosol reaction chamber

The kinetics of the heterogeneous hydrolysis of N 2O 5 on some of the major components of mineral dust and sea salt aerosol have been investigated in an environmental aerosol chamber. Gas-phase N 2O 5 undergoes heterogeneous reaction to form HNO 3 on carbonate, clay and oxide minerals. The nitric acid hydrolysis product was promptly detected in the gas phase concomitant with the decay of N 2O 5 over time. The N 2O 5 decay kinetics were measured and analyzed assuming first-order reaction kinetics. When normalized for surface area, heterogeneous decay of N 2O 5 on the different minerals followed the reactivity trend; kaolinite > hematite > montmorillonite > calcite>quartz. N 2O 5 decay was faster on all of the mineral dust aerosol components relative to NaCl, a major component of sea salt, at a relative humidity (RH) below the NaCl deliquescence point. The measured heterogeneous uptake coefficients were over an order of magnitude larger on several of the mineral dust aerosol compared to NaCl. The uptake coefficient was found to increase with RH.