Identification of Arcobacter species using phospholipid and total fatty acid profiles.

High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were used to analyze the phospholipids and fatty acids of four Arcobacter species (becoming routinely isolated from a wide variety of food sources, especially of animal origin) to provide information for the identification within these species. Phospholipid differences were observed in the HPLC profiles. GC-MS analysis provided a complete fatty acid composition for each arcobacter that after pattern recognition analysis allows taxonomic classification of each species.

Evaluation of a hydrogen laser vacuum ultraviolet source for photoionization mass spectrometry of pharmaceuticals.

A photoionization hydrogen laser time-of-flight mass spectrometer system (H2-TOFMS) has been evaluated for the rapid analysis of drugs of abuse and pharmaceutical agents extracted from prescription tablets and spiked urine samples. The spectra obtained using the H2-TOFMS showed primarily intact molecular ions (M+*) after introduction by a heated probe and irradiation with vacuum ultraviolet (VUV) photons from the laser. Samples analyzed by this technique required only a simple solid-phase extraction step; no chromatographic separation or derivatization was necessary to identify the drugs of abuse or pharmaceutical agents.

Tandem mass spectrometry studies of green tea catechins. Identification of three minor components in the polyphenolic extract of green tea.

Liquid chromatography/electrospray ionization mass and tandem mass spectrometry (MS/MS) techniques were used to identify two minor components and one new compound in the polyphenolic extract of green tea (Camellia sinensis). Identification and structure assignments were based on previously reported sub-structural features in the MS/MS product, precursor and neutral loss scans of reference samples. The structures of two minor components, related to the known green tea components epicatechin gallate (ECG, 5) and epigallocatechin gallate (EGCG, 6), are formed by methylation at the 3"-O-position of the gallic acid moiety.

Design and synthesis of conformationally constrained glucagon analogues.

Glucagon was systematically modified by forming lactam bridges within the central region of the molecule to give conformationally constrained cyclic analogues. Six cyclic glucagon analogues have been designed and synthesized. They are c[Asp(9),Lys(12)][Lys(17,18), Glu(21)]glucagon-NH(2) (1), c[Asp(9),Lys(12)]glucagon-NH(2) (2), c[Lys(12),Asp(15)]glucagon-NH(2) (3), c[Asp(15), Lys(18)]glucagon-NH(2) (4), [Lys(17)-c[Lys(18), Glu(21)]glucagon-NH(2) (5), and c[Lys(12),Asp(21)]glucagon-NH(2) (6).

Mass spectrometry of 3,5- and 4,5-dicaffeoylquinic acids and selected derivatives.

The mass spectral properties of 3,5- and 4,5-dicaffeoylquinic acids (DCQAs) and selected derivatives were examined using electron ionization (EI), fast atom bombardment (FAB) and electrospray ionization (ESI). EI analysis of the trimethylsilyl derivatives provides molecular mass (M(r)) information, but the spectrum is dominated by fragment ions of the caffeic acid group; isomers cannot be differentiated using EI. FAB analysis, in both the positive and negative ion detection modes, provides M(r) information on the free compounds, but little fragmentation is observed using normal scan conditions.

Urinary nucleosides.

The methods of analysis, origins, and clinical significance of urinary nucleosides are reviewed through 1997. Structures, chromatographic and mass spectral data and references to the clinical literature are presented for each of the 57 nucleosides currently identified in normal and pathogenic human urine samples. Data from the HPLC separation and GC/MS analysis of 37 individual HPLC fractions are presented and discussed.

Mass spectrometry of selected components of biological interest in green tea extracts.

Mass spectrometric methods including EIMS, FABMS, and LC/ESIMS have been surveyed as tools for the detection of catechins in extracts of green tea (Camellia sinensis). EIMS provide both molecular weight and structure information, including epimer differentiation, on compounds 1, 2, and 4 and some structural information with compounds 5 and 6. FABMS gives both molecular weight and structure information, by an retro-Diels-Alder mechanism, on all compounds.

Mass spectrometry of nucleotides and oligonucleotides.

Recent advances in the use of mass spectrometry for the determination of the molecular weight and sequencing of oligonucleotides are discussed. Matrix-assisted laser desorption (MALDI) and electrospray ionization (ESI) mass spectrometry have been shown to be especially important techniques for both molecular weight assignment and sequencing of oligonucleotides, and are the focus of this article which covers the literature through early 1996.

Isolation of isoflavones from soy-based fermentations of the erythromycin-producing bacterium Saccharopolyspora erythraea.

A search for an abundant and economical source of isoflavones, particularly genistein, led to the discovery that the erythromycin-producing organism Saccharopolyspora erythraea also produces this promising new cancer-prevention agent. Erythromycin fermentation is a large-scale, soybean-based process used world-wide for the commercial production of this medically important antibiotic. Results from this study indicate that genistin (the glucoside form of genistein), which is added to the fermentation in the soybean media, was converted to genistein through the action of a beta-glucosidase produced by the organism.

Evaluation of mass spectrometric techniques for characterization of engineered proteins.

Mass spectrometric characterization of engineered proteins has been examined using bovine recombinant Acyl-CoA-Binding Protein (rACBP), [15N]-labeled rACBP, and a number of sequence variants of ACBP produced by site-directed mutagenesis. The mass spectrometric techniques include ESIMS and MALDIMS for analysis of the intact protein. Peptide maps have been obtained either by direct analysis of enzymatically derived mixtures by PDMS, ESIMS, and MALDIMS or by off- and on-line HPLC-mass spectrometry.

Synthesis of thiazole-4-carboxamide-adenine difluoromethylenediphosphonates substituted with fluorine at C-2' of the adenosine.

Synthesis of an analogue 3 of thiazole-4-carboxamide adenine-dinucleotide (TAD) in which the beta-oxygen atom of the pyrophosphate bridge is replaced by a difluoromethylene group has been achieved. Likewise, 2'-deoxy-2'-fluoroadenosine containing analogues of TAD (4) and its difluoromethylenediphosphonate congener (5) have been synthesized. Adenosine 5'-difluoromethylenediphosphonate (8) was prepared from 5'-O-tosyladenosine (6) and tris(tetra-n-butylammonium)difluoromethylenediphosphonate (7) by a modified procedure of Poulter's.

Urinary excretion of modified nucleosides as biological marker of RNA turnover in patients with cancer and AIDS.

Using boronate gel affinity chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC), a method for the simultaneous determination of 12 urinary modified nucleosides has been developed. The RP-HPLC fractions were identified by gas chromatography/mass spectrometry analysis. The HPLC quantitation of urinary nucleoside levels before and after surgery of cancer patients suggested that urinary 5'-deoxy-5'-methylthioadenosine and N-[(9-beta-D-ribofuranosyl-9H-purine-6-yl) carbamoyl]-L-threonine (t6A) levels were helpful in monitoring therapeutic effects in cancer patients.

Gas chromatography/mass spectrometric analysis of urinary nucleosides in cancer patients; potential of modified nucleosides as tumour markers.

Analysis of urine from cancer patients by capillary gas chromatography/mass spectrometry positively identified 14 urinary nucleosides including several modified nucleosides. Levels of the modified nucleosides 1-methyl-adenosine, 2-methylguanosine, N2,N2-dimethylguanosine and 1-methylinosine as well as the total nucleoside level were elevated in the urine when a malignant tumour was present; the levels of N2,N2-dimethylguanosine were found to correlate with the stage of the cancer.

Characterization of linear and cyclic glucagon analogs by fast atom bombardment mass spectrometry.

Fast atom bombardment mass spectral mapping of endoproteinase Asp-N digest mixtures is used for characterization of new synthetic linear and cyclic glucagon analogs. The results allow rapid identification of sequence modifications in linear glucagon analogs. For the cyclic compounds, the technique allows confirmation of the presence and position of the cyclic amide bond, as well as verification of the sequence of the modified glucagon analogs.

The mass spectrometry of taxol.

The antitumor agent taxol has been examined by electron ionization, chemical ionization, and fast atom bombardment mass spectrometry. Three ion series are observed: (1) the M-series, characteristic of the intact molecule; (2) the T-series, with fragments derived from the taxane ring; and (3) the S-series representing the C-13 side chain. Neutral losses dominate each series of ions and serve to verify the presence and number of functionalities in each portion of the molecule.

Estimation of whole-body RNA catabolism based on the urinary modified nucleoside levels of cancer and AIDS patients.

From the relationship between the molar ratio of nucleosides calculated stoichiometrically from modified nucleoside occurrences in major RNA species and the proportion of rRNA to all of RNA contents in average tissues, the increase of rRNA contents in cancer tissues growing rapidly was found. Thus, we found that selected urinary modified nucleoside levels were very useful as a biological marker of cancer and AIDS, as well as a good indicator of whole-body metabolic conditions of RNAs.

Isolation and identification of urinary nucleosides. Applications of high-performance liquid chromatographic methods to the synthesis of 5'-deoxyxanthosine and the simultaneous determination of 5,6-dihydrouridine and pseudouridine.

Modified nucleosides from pooled normal human urine were extracted using a boronate affinity gel column and fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC). The major constituents in each of the 30 RP-HPLC fractions were determined by gas chromatography-mass spectrometry of the trimethylsilyl derivatives of the fractions. The same RP-HPLC method was used in the synthesis of 5'-deoxyxanthosine from authentic 5'-deoxyadenosine.

Analysis, identification and determination of urinary modified nucleosides of cancer and AIDS patients.

Modified nucleoside levels in urine samples collected before and after surgery from seven patients with malignant gastrointestinal cancer were examined by the reversed-phase HPLC method. Those of an AIDS patient, a breast cancer patient, and pooled normal urines were also compared. To monitor the effects of therapy on cancer patients, the levels of modified nucleosides, especially t6A and MTA, were found to be fairly effective.

Deuterium-labeled 3-nitrobenzyl alcohol as a matrix for fast atom bombardment mass spectrometry.

The utility of deuterium-labeled 3-nitrobenzyl alcohol (DNBA) as a fast atom bombardment (FAB) matrix for establishing the number of exchangeable hydrogens present in a molecule is illustrated by the analysis of five selected antitumor agents. A method for the simple preparation of this labeled matrix is described. The use of DNBA may be of value for samples which provide no FAB spectra when deuterium-labeled glycerol is used as a matrix.

The identification of 5,6-dihydrouridine in normal human urine by combined gas chromatography/mass spectrometry.

The identification of 5,6-dihydrouridine in normal human urine is reported. Partial purification and isolation of the compound by boronate gel affinity chromatography and reversed-phase high-performance liquid chromatography preceded its characterization as a trimethylsilyl derivative by combined gas chromatography/mass spectrometry. Structure proof is based upon a comparison of mass spectral and chromatographic features of the urinary component to that of an authentic reference sample.

Differentiation of isomeric 2'-, 3'- and 5'-deoxynucleosides by electron ionization and chemical ionization-linked scanning mass spectrometry.

A comparative mass spectral examination of the trimethylsilyl (TMS) derivatives of 2'-, 3'- and 5'-deoxyadenosine, 2'-, 3'- and 5'-deoxyguanosine, 2'-, 3'- and 5'-deoxyxanothosine and 2'- and 5'-deoxy-2-fluoroadenosine is presented. A general compilation of the major fragment ions found in the low-resolution electron ionization (EI) spectra of the eleven deoxynucleosides is given. Chemical ionization (CI)-collisional activation (CA) daughter ion spectra are reported using the deoxyadenosines as model compounds.