High resolution mass spectroscopy of the clavine and ergot-peptide alkaloids.
Explore the source record for details and available documents.
Alkaloids↗
SEARCH · PubMed Health
Results for “high resolution mass spectroscopy”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
5',8-cyclo-dAdo and 8-oxo-dAdo DNA Lesions Are Both Substrates of Adenosine Deaminase: A Preliminary Study.
Genetic information, whether inside or outside the nucleus, is exposed to a variety of harmful physico-chemical factors. Although DNA damage repair systems have been extensively studied, little information about post-repair and non-genomic DNA damage metabolism is available in the literature. Adenosine deaminase (ADA) is an abundant enzyme found on both sides of the cell membrane that regulates the concentration of adenine derivatives. In this article, it has been shown that 7,8-dihydro-8-oxo-2'-deoxyadenosine (OXOdAdo) and (5'R/S) 5',8-cyclo-2'-deoxyadenosine ((5'R/S)cdAdo) are suitable substrates for ADA. For this purpose, theoretical Density Functional Tight Binding and RP-HPLC analyses were applied. The products of ADA activity, i.e., OXOdIno (7,8-dihydro-8-oxo-2'-deoxyinosine) and (5'R/S) cdIno ((5'R/S) 8-cyclo-2'-deoxyinosine), were identified and confirmed by high-resolution mass spectroscopy. Although the (5'R) and (5'S)cdAdo enzymatic deamination processes are much slower (34% and 32% after 168 h, respectively) than the process observed for dAdo, 5',8-cyclo-2'-deoxyinosine should be considered when monitoring cyclopurine levels in physiological fluids. The same should be considered in the case of OXOdAdo, which is completely converted to OXOdIno within one minute and may therefore be less visible than OXOdGuo during mass spectroscopy analysis. Both these observations are important, given the abundance of 2'-deoxyadenosine on both sides of the cell membrane and its potential conversion into OXOdAdo and (5'R/S)cdAdo. They may also explain why the observed level of OXOdAdo is much lower than that of OXOdGuo in cells and physiological fluids, even though their difference in ionisation potential is only 0.25 eV. Future studies are needed to further investigate the metabolism of DNA damage and to identify the enzymes involved in nucleic acid biochemistry.
Adenosine Deaminase↗
Fragmentation and conformation study of ephedrine by low- and high-resolution mass selective UV spectroscopy.
The neurotransmitter molecule, ephedrine, has been studied by mass-selective low- and high-resolution UV resonance enhanced two-photon ionization spectroscopy. Under all experimental conditions we observed an efficient fragmentation upon ionization. The detected vibronic peaks in the spectrum are classified according to the efficiency of the fragmentation, which leads to the conclusion that there exist three different species in the molecular beam: ephedrine-water cluster and two distinct conformers. The two-color two-photon ionization experiment with a decreased energy of the second photon leads to an upper limit of 8.3 eV for the ionization energy of ephedrine. The high-resolution (70 MHz) spectrum of the strongest vibronic peak in the spectrum measured at the fragment (m/z=58) mass channel displays a pronounced and rich rotational structure. Its analysis by the use of a specially designed computer-aided rotational fit process yields accurate rotational constants for the S(0) and S(1) states and the transition moment ratio, providing information on the respective conformational structure.
Ephedrine↗
Electron impact mass spectroscopy for identification of phencyclidine.
The electron impact mass spectrum of phencyclidine (PCP) was studied using both deuterium-labeled analogs and high-resolution mass spectroscopy. The deuterium-labeled compounds used were d5.PCP having 5 deuterium atoms on the phenyl ring, d10.PCP having 10 deuterium atoms on the cyclohexyl ring, and d15.PCP having deuterium atoms on both the phenyl and cyclohexyl rings. The identities of some major fragments and some possible pathways for their formation are shown. Electron impact mass spectroscopy is shown to be a definitive test for the identification of PCP.
Deuterium↗
Implications of inorganic/organic interconversion on fluxes of arsenic in marine food webs.
An organic form of arsenic is commonly encountered in marine organisms; in greysole and shrimp, it accounted for all arsenic found in muscle tissue. It has been isolated from flounder tissue by two independent procedures; it was hydrophilic, cationic, and was not decomposed to inorganic arsenic by hot nitric and sulfuric acids. NMR spectroscopy indicated all nonexchangeable protons to be equivalent; they behaved more like N-methyl protons than As-methyl protons. High-resolution mass spectroscopy from a heated probe yielded a spectrum corresponding to tetramethylarsonium (AsMe4+); the authentic ion, however, had TLC and ion-exchange behavior different from that of the natural product. Infrared spectrometry likewise produced conflicting or uninterpretable data. Decomposition of the compound for analytical purposes was accomplished by dry ashing under oxidizing conditions. Sea urchins, like trout, converted arsenic to an organic form, but to a more limited degree. Arsenic found naturally in sea urchins and in a species of macroalga was also organic. In individual containers, sea urchins were fed on the alga for 7 weeks. During this time they consumed 0.203 +/- 0.075 mg total As and excreted only 0.036 +/- 0.015 mg as feces. Measurement of inorganic As in the seawater did not account for the discrepancy, but measurements of total As did (0.202 +/- 0.095 mg). Sea urchins, like humans, appear to be able to rapidly excrete these organic forms of arsenic.
Animals↗
Screening of acrylamide contents in potato crisps using process variable settings and near-infrared spectroscopy.
In order to study the formation of acrylamide in potato crisps during processing, an experimental design was set up. The design variables were drying time (6 levels), frying temperature (2 levels) and frying time (8 levels). The design contained 36 samples, which were analysed for acrylamide contents using LC high-resolution mass spectroscopy (LC-HRMS), and fat contents using the Soxhlet apparatus. Prior to analysis, all potato crisp samples were ground and analysed on an NIRSystems 6500 near-infrared (NIR) spectrometer. The acrylamide contents were modelled by: (i) design variables using multiple linear regression, (ii) NIR spectra using partial least squares regression (PLSR) and (iii) design variables and NIR spectra in combination using a novel technique combining least squares regression on the former, and PLSR on the latter. The results showed that the NIR spectra alone or in combination with the design variables gave better prediction models for acrylamide than the design variables alone. This implies that the spectra contain chemical information that is not purely a result of the processing variables that were investigated in this experiment. NIR spectroscopy is proposed as a possible tool for screening and identification of potato crisps with a high acrylamide content.
Acrylamide↗
General occurrence of the glucosinolate glucocochlearin within the Cochlearia genus.
A natural compound, glucocochlearin, was isolated from the aerial parts of 10 different Cochlearia species. The purification of this compound was achieved through HPLC. The identity of the product was established mainly on the basis of spectroscopic NMR (1H, 13C, COSY, TOCSY, HMQC, HMBC, J-MOD) and high resolution mass spectroscopy data. This compound can be considered as a chemomarker of the genus Cochlearia.
Brassicaceae↗
Activation of methanol by hepatic postmitochondrial supernatant: formation of a condensation product with 2,4-diaminotoluene.
2,4-Diaminotoluene, an aromatic amine hepatocarcinogen in rats and mice, reacts extensively with formaldehyde produced by the oxidation of methanol to form a single reaction product. Using 1H and 13C NMR and high-resolution mass spectroscopy, this product was shown to be bis(2,4-diamino-5-tolyl)methane. This reaction product is shown to occur under conditions whereby methanol is metabolized to formaldehyde by rat hepatic postmitochondrial supernatant. These results demonstrate a novel reaction of aromatic amines and formaldehyde in biological samples and indicate that methanol as a solvent may become activated in vitro and produce complex interactions with solutes.
Animals↗
Analysis of major components contained in Bis-GMA monomer.
The major components contained in commercial Bis-GMA monomer were isolated by thin layer chromatography (TLC) and identified by NMR and high resolution mass spectroscopy. In addition to the two major components already known (Bis-GMA and Iso-bis-GMA), an unknown hydrophilic third major component was isolated and identified as 2,2-[4-(2-hydroxy-3- methacryloyloxy-1-propoxy)-4'-(2,3-dihydroxy-1-propoxy)]dipheny lpropane. This compound was designated as BIS-GMA-H, because it has a structure of Bis-GMA with one of which methacrylic ester bond hydrolyzed.
Bisphenol A-Glycidyl Methacrylate↗
Biodegradation of carbazole by Ralstonia sp. RJGII.123 isolated from a hydrocarbon contaminated soil.
The use of microorganisms for bioremediation of contaminated soils may be enhanced with an understanding of the pathways involved in their degradation of hazardous compounds. Ralstonia sp. strain RJGII.123 was isolated from soil located at a former coal gasification plant, based on its ability to mineralize carbazole, a three-ring N-heterocyclic pollutant. Experiments were carried out with strain RJGHII.123 and 14C-carbazole (2 mg/L and 500 mg/L) as the sole organic carbon source. At 15 days, 80% of the 2 mg/L carbazole was recovered as CO2, and <1% remained as undegraded carbazole, while 24% of the 500 mg/L carbazole was recovered as CO2 and approximately 70% remained as undegraded carbazole. Several stable intermediates were formed during this time. These intermediates were separated by high performance liquid chromatography (HPLC) and were characterized using high resolution mass spectroscopy (HR-MS) and gas chromatography - mass spectroscopy (GC-MS). At least 10 ring cleavage products of carbazole degradation were identified; four of these were confirmed as anthranilic acid, indole-2-carboxylic acid, indole-3-carboxylic acid, and (1H)-4-quinolinone by comparison with standards. These data indicate that strain RJGII.123 shares aspects of carbazole degradation with previously described Pseudomonas spp., and may be useful in facilitating the bioremediation of NHA from contaminated soils.
Betaproteobacteria↗
Lipophilic N-acylpyrazinamide derivatives: synthesis, physicochemical characterization, liposome incorporation, and in vitro activity against Mycobacterium avium-intracellulare.
N-acetyl-(2), N-caproyl-(3), N-capryl-(4) and N-palmitoyl-pyrazinamide (5) were synthesized by reacting pyrazinamide (1) with acetic anhydride to prepare (2), or by reacting (1) in chloroform with the corresponding acid chlorides to prepare (3-5). Products were identified by high resolution mass spectroscopy, elemental analysis, and 1H NMR. Melting points, enthalpies of fusion, solubility and octanol-water partition coefficients were determined. Hydrolysis of (2) indicated a pseudo first-order, pH-dependent degradation reaction. Apparent half life times of degradation ranged from 74.2 hours at pH 3 to 5.4 hours at pH 7.34. Derivative (5) was incorporated in liposomes consisting of soy phosphatidylcholine and dipalmitoylphosphatidylglycerol (7:3 molar ratio). The in vitro susceptibility of Mycobacterium avium-intracellulare (MAI) to the liposomal compound containing (5) was tested. MAI was susceptible to (5) at concentrations of 12.5-25 micrograms/ml, although MAI is not susceptible to the parent drug (1). Thus, a new class of antimycobacterial agents with physicochemical properties suitable for stable incorporation within liposomes and high antibiotic efficacy against MAI is presented.
Acetylation↗
Serum proteomic profiling can discriminate prostate cancer from benign prostates in men with total prostate specific antigen levels between 2.5 and 15.0 ng/ml.
PURPOSE: Artificial intelligence based pattern recognition algorithms have been developed and successfully used to analyze complex serum proteomic data streams generated by surface enhanced, laser desorption ionization time-of-flight mass spectroscopy. In the current study we used a high performance, hybrid quadrupole time-of-flight mass spectrometer to generate discriminatory serum proteomic profiles to determine if this technology could be used to determine the need for prostate biopsy in men with elevated prostate specific antigen (PSA). MATERIALS AND METHODS: Serum samples were collected from 154 men with serum PSA 2.5 to 15.0 ng/ml and/or abnormal digital rectal examination prior to transrectal ultrasound guided biopsy. Serum samples were applied to WCX2 (weak cation exchange protein chip) Protein Arrays (Ciphergen Biosystems, Fremont, California) by a Biomek 2000 robotic liquid handler (Beckman-Coulter, Chaska, Minnesota) and low molecular weight (less than 20 kDa) proteomic patterns were generated with an API QSTAR Pulsar i LC/MS/MS System (Applied Biosystems, Framingham, Massachusetts). High resolution mass spectra were analyzed with a pattern recognition bioinformatics tool, that is Proteome Quest beta version 1.0 (Correlogic Systems, Inc., Bethesda, Maryland), in an attempt to identify and discover key discriminating ion signatures. Serum samples from 63 men (2 or more negative prostate biopsies in 23, 1 negative biopsy in 10 and biopsy detected prostate cancer [CaP] in 30) were used to train the diagnostic algorithm. The remaining 91 samples, including 28 of prostate cancer and 63 of 1 or more negative biopsies, were analyzed in blinded fashion. RESULTS: The most discriminatory model was found using the WCX2 chip. Testing the remaining 91 men with this model yielded 100% sensitivity and 67% specificity. In other words, if the proteomic pattern had been used to determine the need for prostate biopsy in this cohort of men with PSA between 2.5 and 15.0 ng/ml, 67% (42 of 63) with negative biopsies would have avoided unnecessary biopsy, while no cancers would have been missed. CONCLUSIONS: Our data demonstrate that high resolution mass spectroscopy can generate serum proteomic patterns that discriminate men with elevated PSA due to benign processes from men with CaP even when PSA is within the diagnostic gray zone. We are currently expanding the testing set to determine the reliability of this new technology to decrease unnecessary prostate biopsies without compromising the detection of curable CaP.
Algorithms↗
Novel cytotoxic bufadienolides derived from bufalin by microbial hydroxylation and their structure-activity relationships.
Microbial transformation was used to prepare novel cytotoxic bufadienolides. Twelve products (3-14) were obtained from bufalin (1) by the fungus Mucor spinosus. Their structures were elucidated by high-resolution mass spectroscopy (HR-MS) and extensive NMR techniques, including 1H NMR, 13C NMR, DEPT, 1H-1H correlation spectroscopy (COSY), two dimensional nuclear Overhauser effect correlation spectroscopy (NOESY), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond coherence (HMBC). Compounds 3, 4, 9 and 11-14 are new mono- or dihydroxylated derivatives of bufalin with novel oxyfunctionalities at C-1beta, C-7beta, C-11beta, C-12beta and C-16alpha positions. The in vitro cytotoxic activities against human cancer cell lines of 3-14, together with 16 biotransformed products derived from cinobufagin (15-30) were determined by the MTT method, and their structure-activity relationships (SAR) were discussed.
Bacteria↗
Isolation and identification of novel tocotrienols from rice bran with hypocholesterolemic, antioxidant, and antitumor properties.
Two novel tocotrienols were isolated from stabilized and heated rice bran, apart from the known alpha-, beta-, gamma-, and delta-tocopherols and tocotrienols. These new tocotrienols were separated by HPLC, using a normal phase silica column. Their structures were determined by ultraviolet, infrared, nuclear magnetic resonance, circular dichroism, and high-resolution mass spectroscopies and established as desmethyl tocotrienol [3, 4-dihydro-2-methyl-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol] and didesmethy tocotrienol [3, 4-dihydro-2-(4,8,12-trimethyltrideca-3'(E),7'(E), 11'-trienyl)-2H-1-benzopyran-6-ol]. These tocotrienols significantly lowered serum total and LDL cholesterol levels and inhibited HMG-CoA reductase activity in chickens. They had much greater in vitro antioxidant activities and greater suppression of B16 melanoma cell proliferation than alpha-tocopherol and known tocotrienols. Results indicated that the number and position of methyl substituents in tocotrienols affect their hypocholesterolemic, antioxidant, and antitumor properties.
Animals↗
An assessment of estrogenic organic contaminants in Canadian wastewaters.
A suite of 30 primarily estrogenic organic wastewater contaminants was measured in several influent/effluent wastewater samples from four municipal wastewater treatment plants and effluents from one bleached kraft pulp mill (BKME) using an ultra-trace analytical method based on gas chromatography-high resolution mass spectroscopy (GC-HRMS). In vitro recombinant yeast assay detection of the estrogenic equivalent (EEq) on whole and solid phase extracted (SPE) and fractionated wastewater was also performed. 19-norethindrone was the most frequently detected and abundant (26-224 ng/L) of all the synthetic estrogens/progesterones in the influent samples. 17alpha-ethinylestradiol was the more frequently detected synthetic estrogen/progesterone in the effluents occurring at or below 5 ng/L with some sporadic occurrences of up to 178 ng/L. The greatest levels of steroidal estrogens in municipal effluents were E1>E2>E3 which were all <20 ng/L. Nonylphenol and di(2-ethylhexyl) phthalate were found to be the highest non-steroidal synthetic compounds surveyed in both municipal influent and effluent samples, both occurring at 6-7 microg/L in municipal effluents. BKME contained relatively large amounts of the plant sterol stigmasterol (4 microg/L) but low amounts of fecal sterols, and steroidal estrogens (E2 only at 6 ng/L) when compared to the municipal effluents. In vitro EEq in the wastewater surveyed ranged from 9-106 ng E2/L and ranked from municipal influent>municipal effluent approximately BKME, with most of the estrogenicity fractionating in the 100% methanol SPE fraction followed by a secondary amount in the diethyl ether (for municipal) or methyl-tert butyl ether (for BKME) SPE fractions. Most correlations between chemical and in vitro estrogenic equivalency were weak (p>0.05 in most cases). Unexpected inverse correlations between in vitro estrogenic activity and concentrations of the estrogenic contaminant bisphenol A were found which likely contributed to the weakness of these correlations. A modified toxicity identification and evaluation procedure was continued with the SPE extracts from the more potent 100% methanol SPE fractions of municipal effluent. High performance liquid chromatography band elution retention times, based on in vitro estrogen detection, indicated that steroidal estrogens such as E2 were responsible for most of the estrogenicity of the samples. Subsequent collection and GC-MS analysis of active bands did not confirm the presence of steroidal estrogens, but expanded the possibility of phthalate esters (i.e. dibutyl phthalate) and natural sterols (i.e. beta-sitosterol) contributing to the overall estrogenic load.
Benzhydryl Compounds↗
Norlignans from Sequoia sempervirens.
Six new norlignans, named sequosempervirins B-G (1-6), together with three known norlignans, agatharesinol (7), agatharesinol acetonide (8), and sugiresinol (9), were isolated from the branches and leaves of Sequoia sempervirens. Their structures were determined mainly by high-resolution mass spectroscopy (HR-MS), and various 1D- and 2D-NMR methods, as well as, in the case of 1, by means of X-ray diffraction. Compound 8 showed anticancer activity towards the A549 non-small-cell lung-cancer cell line (IC50 = 27.1 microM). The acetone extract of S. sempervirens was found to be antifungal towards Candida glabrata (IC50 = 15.98 microg/ml), and both the acetone and MeOH extracts inhibited the proteolytic activity of cathepsin B (IC50 = 4.58 and 5.49 microg/ml, resp.).
Antifungal Agents↗
Microsomal activation of fluoranthene to mutagenic metabolites.
The in vitro metabolism of fluoranthene (FA) was assessed by incubating 3-[3H]FA, the synthesis of which is described, with rat hepatic microsomal enzymes. Several metabolites including the FA 2,3-diol, FA 2-3,-quinone, 3-OH-FA, 1-OH-FA, and 8-OH-FA were isolated by high-pressure liquid chromatography and identified by comparison of chromatographic properties and uv-visible spectra with those of synthetic standards. The major metabolite produced over the FA concentration range studied (23-233 microM) was FA 2,3-diol, accounting for 29-43% of the total extractable metabolites. This diol was characterized further by high-resolution mass spectroscopy and H-NMR and determined to be identical in structure to the trans-2,3-dihydroxy-2,3-dihydrofluoranthene. The FA 2,3-diol, syn and anti 2,3-diol-1,10b-epoxides, FA 2,3-quinone, and FA 7,8-diol were all shown to be mutagenic toward Salmonella typhimurium TM677. The FA 1,10b-diol and syn and anti FA 1,10b-diol-2,3-epoxides were not mutagenic. The epoxide hydrolase inhibitor, 3,3,3-trichloropropylene oxide, markedly reduced the mutagenic potency of FA while concurrently inhibiting FA 2,3-diol production but not overall FA metabolism. These results suggests that a major metabolic activation pathway of FA resulting in the production of mutagenic species involves the formation of the FA 2,3-diol and the subsequent oxidation of this diol to a FA 2,3-diol-1,10b-epoxide. Another minor activation pathway with mutagenic endpoints may involve the formation of the 7,8-diol.
Animals↗
Chemical evolution in space--a source of prebiotic molecules.
In Laboratory Astrophysics at Leiden University a laboratory analog for following the chemical evolution of interstellar dust in space shows that the dust contains the bulk of organic material in the universe. We follow the photoprocessing of low temperature (10 K) mixtures of ices subjected to vacuum ultraviolet radiation in simulation of interstellar conditions. The most important, but necessary, difference is in the time scales for photo-processing. One hour in the laboratory is equivalent to one thousand years in low density regions of space and as much as, or greater than, ten thousand to one million years in the depths of dense molecular clouds. The ultimate product of photoprocessing of grain material in the laboratory is a complex nonvolatile residue which is yellow in color and soluble in water and methanol. The molecular weight is greater than the mid-hundreds. The infrared absorption spectra indicate the presence of carboxylic acid and amino groups resembling those of other molecules of presumably prebiological significance produced by more classical methods. One of our residues, when subjected to high resolution mass spectroscopy gave a mass of 82 corresponding to C4H6H2 after release of CO2 and trace ammounts of urea suggesting amino pyroline rings. The deposit of prebiotic dust molecules occurred as many as 5 times in the first 500-700 million years on a primitive Earth by accretion during the passage of the solar system through a dense interstellar cloud. The deposition rate during each passage is estimated to be between 10(9) and 10(10) g per year during the million or so years of each passage; i.e., a total deposition of 1O(9)-10(10) metric tons of complex organic material per passage.
Cosmic Dust↗