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1.
The natural 15N abundance
( 15N value) in acetylpropyl derivatives of
amino acids and in ethyloxycarbonyl derivatives of polyamines was
determined using a gas chromatography/combustion/mass
spectrometer-(GC/C/MS). 15N value
determined for 12 amino acids and five polyamines by GC/C/MS were identical
to those obtained by a direct combustion method using an automatic nitrogen
and carbon analysis (ANCA) mass spectrometer, the difference being less
than 1.0% in most cases. The GC/C/MS
method was used to analyse 15N values in
the amino acids and polyamines from root nodules of pea and faba bean and
from stem nodules of Sesbania rostrata. The analysis
of 15N values revealed that homospermidine
had high 15N values, as much as +40%, while
the amino acids investigated had 15N values
between -3 and +6%, putrescine between +2 and +8%, cadaverine between +1
and +7%, spermidine between -2 and +4%, and spermine between 0 and +6%. The
mechanism of 15N enrichment in homospermidine is
discussed. 相似文献
2.
Progress in metabolomic analysis now allows the evaluation of food quality. This study aims to identify the metabolites in meat from livestock using a metabolomic approach. Using gas chromatography–mass spectrometry (GC/MS), many metabolites were reproducibly detected in meats, and distinct differences between livestock species (cattle, pigs, and chickens) were indicated. A comparison of metabolites between tissues types (muscle, intramuscular fat, and intermuscular fat) in marbled beef of Japanese Black cattle revealed that most metabolites are abundant in the muscle tissue. Several metabolites (medium-chain fatty acids, etc.) involved in triacylglycerol synthesis were uniquely detected in fat tissue. Additionally, the results of multivariate analysis suggest that GC/MS analysis of metabolites can distinguish between cattle breeds. These results provide useful information for the analysis of meat quality using GC/MS-based metabolomic analysis. ABBREVIATIONS: GC/MS: gas chromatography-mass spectrometry; NMR: nuclear magnetic resonance; MS: mass spectrometry; IS: 2-isopropylmalic acid; MSTFA: N-Methyl-N-trimethylsilyltrifluoroacetamide; CV: coefficient of variation; TBS: Tris-buffered saline; MHC: myosin fast type; PCA: principal component analysis; OPLS-DA: orthogonal partial least-squares discriminant analysis; O2PLS: two-way orthogonal partial least-squares 相似文献
3.
Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) of propyl chloroformate and iTRAQ ® derivatized amino acids, respectively, to conventional amino acid analysis. The GC–MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC–MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ ® tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC–MS, and iTRAQ ®–LC–MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27 ± 5.22, 21.18 ± 10.94, and 18.34 ± 14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39 ± 5.35, 6.23 ± 3.84, and 35.37 ± 29.42. Both GC–MS and iTRAQ ®–LC–MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. 相似文献
4.
Hyphal anastomosis testing and molecular methods have been the primary criteria employed to understand the evolutionary and taxonomic relationships of the soil-borne fungal plant pathogen Rhizoctonia solani species complex. In this study, a metabolomics-based approach for characterizing and identifying isolates of R. solani using gas chromatography/mass spectrometry (GC/MS) metabolite profiling and footprinting was developed. Multivariate and hierarchical cluster analyses of GC/MS data provided resolution of isolates belonging to anastomosis groups (AGs) 1–6, 9, and 10 of R. solani. Clustering of R. solani AG-3 isolates, based on host origin, was also observed and attributed to metabolite-biomarkers belonging to amino, carboxylic and fatty acids. The chemotaxonomic approach using metabolomics is a high-throughput methodology that complements existing molecular approaches for the taxonomic investigation of Rhizoctonia isolates and monitoring of fungal metabolism. 相似文献
5.
Oxindole-3-acetic acid (OxIAA) has been identified in germinating seeds of Scots pine ( Pinus sylvestris) using gas chromatography-mass spectrometry. Seeds germinated for 5 d contained 2.7 ng OxIAA·g -1 (dry weight) whereas ungerminated seeds contained 0.2 ng·g -1. Isotopically labelled OxIAA was formed in seeds incubated with [1- 14C]-, [2- 14C]- or [ 2H 5]indole-3-acetic acid.Abbreviations DDC
sodium diethyldithiocarbamate
- GC
gas chromatography
- HPLC
high-performance liquid chromatography
- IAA
indole-3-acetic acid
- MS
mass spectrometry
- OxIAA
oxindole-3-acetic acid
- PVP
polyvinylpyrrolidone
- TMS
trimethylsilyl 相似文献
6.
Cytokinins were extracted from two cultures of tobacco crown gall tumor tissue: an unorganized tissue and a teratoma which produced leafy shoots. On Sephadex LH-20 column chromatography, extracts of both types of tissue yielded two peaks of cytokinin activity with elution volumes similar to ribosylzeatin and zeatin. Ribosylzeatin and zeatin were detected and quantified by coupled gas chromatography — mass spectrometry selected ion monitoring (GC/MS SIM), comparable quantities being found in the two extracts. Full mass spectral evidence for the presence of ribosylzeatin in both tissues was obtained. No evidence was found for the presence of N 6-( 2-isopentenyl)adenosine (i 6Ade) or N 6-( 2-isopentenyl)adenine (i 6Ade) although these compounds have been reported to occur in cytokinin-habituated tobacco callus tissues.Abbreviations BAP
6-benzylaminopurine
- GC
gas chromatography
- GC/MS
coupled gas chromatography-mass spectrometry
- i 6 Ade
N 6-( 2-isopentenyl)adenine
- i 6 Ado
N 6-( 2-isopentenyl)adenosine
- RFE
rotary film evaporation
- SIM
selected ion monitoring
- TLC
thin-layer chromatography
- TMS
trimethylsilyl 相似文献
7.
Quantification of fatty acids has been crucial to elucidate lipid biosynthesis pathways in plants. To date, fatty acid identification and quantification has relied mainly on gas chromatography (GC) coupled to flame ionization detection (FID) or mass spectrometry (MS), which requires the derivatization of samples and the use of chemical standards for annotation. Here we present an alternative method based on a simple procedure for the hydrolysis of lipids, so that fatty acids can be quantified by liquid chromatography mass spectrometry (LC‐MS) analysis. Proper peak annotation of the fatty acids in the LC‐MS‐based methods has been achieved by LC‐MS measurements of authentic standard compounds and elemental formula annotation supported by 13C isotope‐labeled Arabidopsis. As a proof of concept, we have compared the analysis by LC‐MS and GC‐FID of two previously characterized Arabidopsis thaliana knock‐out mutants for FAD6 and FAD7 desaturase genes. These results are discussed in light of lipidomic profiles obtained from the same samples. In addition, we performed untargeted LC‐MS analysis to determine the fatty acid content of two diatom species. Our results indicate that both LC‐MS and GC‐FID analyses are comparable, but that because of higher sensitivity and selectivity the LC‐MS‐based method allows for a broader coverage and determination of novel fatty acids. 相似文献
8.
Hyphal anastomosis testing and molecular methods have been the primary criteria employed to understand the evolutionary and taxonomic relationships of the soil-borne fungal plant pathogen Rhizoctonia solani species complex. In this study, a metabolomics-based approach for characterizing and identifying isolates of R. solani using gas chromatography/mass spectrometry (GC/MS) metabolite profiling and footprinting was developed. Multivariate and hierarchical cluster analyses of GC/MS data provided resolution of isolates belonging to anastomosis groups (AGs) 1–6, 9, and 10 of R. solani. Clustering of R. solani AG-3 isolates, based on host origin, was also observed and attributed to metabolite-biomarkers belonging to amino, carboxylic and fatty acids. The chemotaxonomic approach using metabolomics is a high-throughput methodology that complements existing molecular approaches for the taxonomic investigation of Rhizoctonia isolates and monitoring of fungal metabolism. 相似文献
9.
The occurrence of dioic, hydroxy, branched, and unsaturated fatty acids in cyanobacteria of the genus Aphanizomenon growing in different freshwater lakes has been studied. Unusual dicarboxylic (from 4.52 to 7.14%) and other fatty acids were identified by gas chromatography/mass spectrometry (GC/MS). 相似文献
10.
The spent medium of suspension-cultured cells of Lupinus polyphyllus was analyzed by capillary GC and GC-MS and shown to contain ethanol (up to 160 mmol l -1), organic acids (lactate, benzoate, succinate, fumarate, malate), amino acids (main components: alanine, glycine, serine, aspartate, ornithine, glutamate), and quinolizidine alkaloids (lupanine and an uncharacterized malonylderivative). In addition, cells obviously secrete polysaccharides and enzymes (acid phosphatase, phosphodiesterase, DNAse, esterase, -mannosidase, -galactosidase, -glucosidase, lipase, protease and peroxidase) into the medium. Typically these enzymes are localized in the vacuole of intact cells. Cytosolic enzymes, such as glutamate dehydrogenase and malate dehydrogenase were retained by the cells. Peroxidase is overexpressed in suspension-cultured lupin cells but only one basic isoenzyme is secreted, whereas the others are retained in the vacuole. In lupin leaves this isoenzyme is sequestered in the vacuole, implying that secretion is selective and needs a change in the sorting signals of the peroxidase protein. The cell culture medium shares many features of the vacuole. We assume therefore that the medium functions as a lytic compartment. In addition it provides a sink-source system for nutrients and metabolites.Abbreviations ADH
alcohol dehydrogenase
- FW
fresh weight
- GC
gas chromatography
- GC-MS
gas chromatography — mass spectrometry
- POD
peroxidase
- QA
quinolizidine alkaloids 相似文献
11.
By combined gas chromatography-mass spectrometry the gibberellin present in suspensors of heart-shaped embryos of Phaseolus coccineus has been identified as Gibberellin A 1 (GA 1). The amount of GA 1 in 2000 suspensors (452 mg), as estimated by gas chromatography. was 4g. The presence of GA 1 in suspensors of P. coccineus is discussed in relation to our present knowledge of the occurrence of many gibberellins in developing seeds and immature fruits of the same species.Abbreviations FID
flame ionization detector
- GA
gibberellin
- GC
gas chromatography
- MS
mass spectrometry
- PGC
preparative gas chromatography
- Stage A
heart-shaped embryo
- Stage B
cotytedonary embryo
- TMS
trimethylsilyl 相似文献
12.
IntroductionDental calculus is a mineralized microbial dental plaque biofilm that forms throughout life by precipitation of salivary calcium salts. Successive cycles of dental plaque growth and calcification make it an unusually well-preserved, long-term record of host-microbial interaction in the archaeological record. Recent studies have confirmed the survival of authentic ancient DNA and proteins within historic and prehistoric dental calculus, making it a promising substrate for investigating oral microbiome evolution via direct measurement and comparison of modern and ancient specimens.ObjectiveWe present the first comprehensive characterization of the human dental calculus metabolome using a multi-platform approach.MethodsUltra performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) quantified 285 metabolites in modern and historic (200 years old) dental calculus, including metabolites of drug and dietary origin. A subset of historic samples was additionally analyzed by high-resolution gas chromatography–MS (GC–MS) and UPLC–MS/MS for further characterization of metabolites and lipids. Metabolite profiles of modern and historic calculus were compared to identify patterns of persistence and loss.ResultsDipeptides, free amino acids, free nucleotides, and carbohydrates substantially decrease in abundance and ubiquity in archaeological samples, with some exceptions. Lipids generally persist, and saturated and mono-unsaturated medium and long chain fatty acids appear to be well-preserved, while metabolic derivatives related to oxidation and chemical degradation are found at higher levels in archaeological dental calculus than fresh samples.ConclusionsThe results of this study indicate that certain metabolite classes have higher potential for recovery over long time scales and may serve as appropriate targets for oral microbiome evolutionary studies. 相似文献
13.
Combining different chromatography systems, unusual nonprotein amino acids were isolated and unequivocally identified from a small amount (less than 100 g fresh weight) of Amanita gymnopus fruit body. Without obtaining crystals of these amino acids, on the basis of 1H-NMR determination, high resolution mass spectrometry, chlorine analysis and oxidation with L-amino acid oxidase, one of them proved to be a new chloroamino acid, (2 S)-2-amino-5-chloro-4-hydroxy-5-hexenoic acid (G2). The other three were (2 S)-2-amino-5-hexenoic acid (G1), (2 S)-2-amino-4,5-hexadienoic acid (G3) and (2 S)-2-amino-5-hexynoic acid (G4). Amino acid (G1) was also encountered for the first time in natural products. Amino acid (G3) has been reported from several kinds of fungi belonging to Amanita, subgenus Lepidella. The occurrence of amino acid (G4) was already reported from Cortinarius claricolor.Part 23 in the series Biochemical studies of nitrogen compounds in fungi. Part 22, Hatanaka, S. I. et al. 1985. Trans. Mycol. Soc. Japan 26: 61–68. 相似文献
14.
Five homologous acetylated acylglycerols of 3‐hydroxyfatty acids (chain lengths C(14) – C(18)), named euphrasianins A – E, were characterized for the first time in Euphrasia rostkoviana Hayne (Orobanchaceae) by gas chromatography/mass spectrometry (GC/MS) and high‐performance liquid chromatography/atmospheric pressure chemical ionization‐mass spectrometry (HPLC/APCI‐MS n). In addition to mass spectrometric data, structures of euphrasianins were verified via a three‐step total synthesis of one representative homologue (euphrasianin A). The structure of the latter was confirmed by 1D‐ and 2D‐NMR experiments as well as high‐resolution electrospray ionization‐mass spectrometry (HR‐ESI‐MS). The absolute configuration of the 3‐hydroxyfatty acid moiety at C(3) was found to be R in the natural euphrasianins, which was determined by alkaline hydrolysis and methylation of a purified fraction, followed by chiral GC analysis. Furthermore, in extracts of Euphrasia tetraquetra (Bréb .) Arrond . euphrasianins C and E were detected exclusively, indicating that this subclass of lipid constituents is possibly valuable for fingerprinting methods. 相似文献
15.
Fatty aldehydes are important components of the cellular lipidome. Significant interest has been developed towards the analysis of the short chain α,β-unsaturated and hydroxylated aldehydes formed as a result of oxidation of polyunsaturated fatty acids. Multiple gas chromatography-mass spectrometry (GC/MS) and subsequently liquid chromatography-mass spectrometry (LC/MS) approaches have been developed to identify and quantify short-chain as well as long-chain fatty aldehydes. Due to the ability to non-enzymaticaly form Schiff bases with amino groups of proteins, lipids, and with DNA guanidine, free aldehydes are viewed as a marker or metric of fatty acid oxidation and not the part of intracellular signaling pathways which has significantly limited the overall attention this group of molecules have received. This review provides an overview of current GC/MS and LC/MS approaches of fatty aldehyde analysis as well as discusses technical challenges standing in the way of free fatty aldehyde quantitation. 相似文献
16.
Eleven species of wild mushrooms which belong to Boletaceae and Russulaceae families were examined by gas chromatography (GC) and gas chromatography–mass spectrometry (GC/MS) analysis for the presence of fatty acids. As far as we know, the fatty acid profiles of B. purpureus and B. rhodoxanthus were described for the first time. Twenty‐six fatty acids were determined. Linoleic (19.5 – 72%), oleic (0.11 – 64%), palmitic (5.9 – 22%) and stearic acids (0.81 – 57%) were present in the highest contents. In all samples, unsaturated fatty acids dominate. Agglomerative hierarchical clustering was used to display the correlation between the fatty acids and their relationships with the mushroom species. Based on the fatty acids profile in the samples, the mushrooms can be divided into two families: Boletaceae and Russulaceae families, using cluster analysis. 相似文献
17.
A metabolite profiling methodology based on capillary gas chromatography/mass spectrometry (GC/MS) was employed to investigate
time-dependent metabolic changes in the course of the sprouting of mung beans ( Vigna radiata). Intact mung beans and sprout samples taken during the germination process were subjected to an extraction and fractionation
procedure covering a broad spectrum of lipophilic (e.g. fatty acid methyl esters, hydrocarbons, fatty alcohols, sterols) and
hydrophilic (e.g. sugars, acids, amino acids, amines) low molecular weight constituents. Investigation of the obtained fractions
by GC resulted in the detection of more than 450 distinct peaks of which 146 were identified by means of MS. Statistical assessment
of the metabolite profiling data via principal component analysis demonstrated that the metabolic changes during the sprouting
of mung beans are reflected by time-dependent shifts of the scores which were comparable for two spouting processes independently
conducted under the same conditions. Analysis of the loadings showed that polar metabolites were major contributors to the
separation along the first principal component. The dynamic changes of single metabolites revealed significantly increased
levels of monosaccharides, organic acids and amino acids and a decrease in fatty acid methyl esters in mung bean sprouts. 相似文献
18.
BackgroundSerum branched-chain and aromatic amino acids (BCAAs and AAAs) have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. MethodsAn isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standards and the amino acids were extracted with acetonitrile, followed by analysis using LC/MS/MS. The LC separation was performed on a reversed-phase C 18 column, and the MS/MS detection was performed via the positive electronic spray ionization in multiple reaction monitoring mode. ResultsSpecific analysis of the amino acids was achieved within 2 min. Intra-run and total CVs for the amino acids were less than 2% and 4%, respectively, and the analytical recoveries ranged from 99.6 to 103.6%. ConclusionA rapid and precise method for the measurement of serum BCAAs and AAAs was developed and may serve as a quick tool for screening serum BCAAs and AAAs in studies assessing diabetes risk. 相似文献
19.
Proteolytic cleavage of recombinant human interferon- (IFN-) expressed in Chinese hamster ovary (CHO) cells during batch fermentation has been monitored by mass spectrometric peptide mapping. IFN- was purified from cell-free culture supernatant by immunoaffinity chromatography and cleaved by endoprotease Asp-N. Peptide fragments were resolved by reverse-phase HPLC and identified by a combination of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and automated N-terminal peptide sequencing. Using this approach, a peptide was identified as the C-terminal fragment of the IFN- polypeptide. Analysis of this peptide by MS indicated that the recombinant IFN- polypeptide secreted by CHO cells was truncated by at least ten amino acids, initially at Gln 133-Met 134. No full length (143 amino acids) polypeptide molecules were observed at any stages of the fermentation. Additional proteolytic cleavages at basic amino acids N-terminal of Gln 133 occurred during the later stages of the culture resulting in a heterogeneous IFN- polypeptide population with 'ragged' C-termini. 相似文献
20.
l-Homoarginine (hArg) has recently emerged as a novel cardiovascular risk factor and to herald a poor prognosis in heart failure patients. Here, we report on the development and thorough validation of gas chromatography–mass spectrometry (GC–MS) and gas chromatography–tandem mass spectrometry (GC– MS/MS) methods for the quantitative determination of hArg in biological samples, including human plasma, urine and sputum. For plasma and serum samples, ultrafiltrate (10 µL; cutoff, 10 kDa) was used. For urine samples, native urine (10 µL) was used. For sputum, protein precipitation by acetone was performed. hArg is derivatized to its methyl ester tri( N-pentafluoropropionyl) derivative; de novo synthesized trideutero-methyl ester hArg is used as the internal standard (IS). Alternatively, [ guanidino- 15N 2]-arginine can be used as an IS. Quantitative analyses were performed after electron-capture negative-ion chemical ionization by selected-ion monitoring in GC–MS and selected-reaction monitoring in GC– MS/MS. We obtained very similar hArg concentrations by GC–MS and GC– MS/MS, suggesting that GC–MS suffices for accurate and precise quantification of hArg in biological samples. In plasma and serum samples of the same subjects very close hArg concentrations were measured. The plasma-to-serum hArg concentration ratio was determined to be 1.12 ± 0.21 (RSD, 19 %), suggesting that blood anticoagulation is not a major preanalytical concern in hArg analysis. In healthy subjects, the creatinine-corrected urinary excretion of hArg varies considerably (0.18 ± 0.22 µmol/mmol, mean ± SD, n = 19) unlike asymmetric dimethylarginine ( ADMA, 2.89 ± 0.89 µmol/mmol). In urine, hArg correlated with ADMA ( r = 0.475, P = 0.040); in average, subjects excreted in the urine about 17.5 times more ADMA than hArg. In plasma of healthy humans, the concentration of hArg is of the order of 2 µM. hArg may be a low-abundance constituent of human plasma proteins. The GC–MS and GC-MS/MS methods we report in this article are useful to study the physiology and pathology of hArg in experimental and clinical settings. 相似文献
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