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1.
In addition to triglochinin, taxiphyllin has been detected as a cyanogenic glucoside in seedlings of Triglochin maritima. Taxiphyllin at first increases during seedling development and then decreases, whereas tri-glochinin increases to a level higher than that ever reached by taxiphyllin and remains there during further seedling development. Two β-glucosidases have also been characterized in these seedlings. One of these shows a distinct specificity for triglochinin, whereas taxiphyllin appears to be the preferred substrate of the other. 相似文献
2.
Michela Tomaiuolo Gennaro Vecchione Maurizio Margaglione Daniela Pisanelli Elvira Grandone 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(28):3292-3299
Homocysteine is an endogenous sulphydryl aminoacid irreversibly catabolized by transsulfuration to cysteine or remethylated to methionine. Increased plasma levels of homocysteine are an independent risk factor for atherosclerosis and cardiovascular disease. Accurate and reliable quantification of this amino acid in plasma samples is essential in clinical practice to explore the presence of a hyperhomocysteinemia, for instance after an ischemic event, or to control a possible adjunctive risk factor in patients at higher risk. In this review, LC–ESI-MS/MS methods are discussed and compared with other analytical methods for plasma homocysteine. LC–ESI-MS/MS is a technique combining the physicochemical separation of liquid chromatography with the analysis of mass spectrometry. It is based on stable-isotope dilution and possesses inherent accuracy and precision. Quantitative analysis is achieved by using commercially available homocystine-d8 as an internal standard. Taking advantage of the high sensitivity and specificity, approaches involving LC–ESI-MS/MS require less laborious sample preparation, no derivatization and produce reliable results. 相似文献
3.
Toshiyuki Suzuki Akira Miyazono Katsuhisa Baba Rieko Sugawara Takashi Kamiyama 《Harmful algae》2009,8(2):233-238
Quantification of diarrhetic shellfish poisoning (DSP) toxins (okadaic acid analogues), and other lipophilic toxins in single-cell isolates of the dinoflagellates Dinophysis fortii, D. acuminata, D. mitra, D. norvegica, D. tripos, D. infundibulus and D. rotundata, collected in coastal waters Hokkaido, Japan in 2005, was carried out by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Okadaic acid (OA), dinophysistoxin-1 (DTX1), 7-O-palmitoyldinophysistoxin-1 (DTX3), pectenotoxin-1 (PTX1), pectenotoxin-11 (PTX11), pectenotoxin-2 (PTX2), pectenotoxin-6 (PTX6), pectenotoxin-2 seco-acid (PTX2sa), yessotoxin (YTX) and 45-hydroxyyessotoxin (45-OHYTX) were quantified by LC–MS/MS. PTX2 was the dominant toxin in D. acuminata, D. norvegica and D. infundibulus whereas both DTX1 and PTX2 were the principal toxins in D. fortii. None of the toxins were detected in D. mitra, D. rotundata and D. tripos. These results suggest that D. fortii is the most important species responsible for DSP contamination of bivalves in Hokkaido. This is the first finding of PTX2 in D. infundibulus, and confirms the presence of PTX2 in Japanese D. acuminata and D. norvegica collected from natural seawater. 相似文献
4.
Miao Yan Huan-De Li Ben-Mei Chen Xiao-Lei Liu Yun-Gui Zhu 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(11-12):883-887
An LC–MS method for the determination of metoclopramide in human plasma was developed and validated. Sample preparation involved extraction with ethyl acetate. Chromatographic separation was performed on a Thermo Hypersil-Hypurity C18 (150 mm × 2.1 mm, 5 μm) with the mobile phase consisting of 40 mM ammonium acetate–methanol–acetonitrile. A single-quadrupole mass spectrometer with an electrospray interface was operated in the selected-ion monitoring mode to detect the [M+H]+ ions at m/z 300 for metoclopramide and at m/z 384 for the internal standard (prazosin). The method was validated over 0.78–50.00 ng mL?1 for metoclopramide. The recovery was 67.8–83.1%, and the limit of quantitation (LOQ) detection was 0.78 ng mL?1 for metoclopramide. The intra- and inter-day precision of the method at three concentrations was 5.0–13.6% with accuracy of 99.2–104.0%. Stability of compounds was established in a battery of stability studies. The method was successfully applied to bioequivalence studies of metoclopramide hydrochloride tablets to obtain the pharmacokinetic parameters. 相似文献
5.
Sumitha K. Reddy Anna Rosengren Sylvia Klaubauf Tejas Kulkarni Eva Nordberg Karlsson Ronald P. de Vries Henrik Stålbrand 《FEBS letters》2013
Phylogenetic analysis of glycoside hydrolase family 2 including Aspergillus sequences and characterised β-mannosidases from other organisms, clusters putative Aspergillus β-mannosidases in two distinct clades (A and B). Aspergillus species have at least one paralog in each of the two clades. It appears that clade A members are extracellular and clade B members intracellular. Substrate specificity analysis of MndA of Aspergillus niger (clade A) and MndB of Aspergillus nidulans (clade B) show that MndB, in contrast to MndA, does not hydrolyse polymeric mannan and has probably evolved to hydrolyse small unbranched β-mannosides like mannobiose. A 3D-model of MndB provides further insight. 相似文献
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9.
Yinxi Huang Lei Liu Chang Shi Junyi Huang Genxi Li 《Biochimica et Biophysica Acta (BBA)/General Subjects》2006
Mitochondrial Ca2+ has been considered a trigger for the release of cytochrome c, which is a critical and early event in the induction of cell apoptosis, although the molecular mechanism underlying this effect is still not fully understood. Here we investigate the interaction between cytochrome c and cardiolipin and the effect of Ca2+ on this interaction using electrochemical methods. Experimental results revealed that modification of cardiolipin onto the surface of a pyrolytic graphite electrode could lead to a rapid direct electron transfer of cytochrome c through the electrostatic interaction between the protein and the cardiolipin. Addition of Ca2+ to the test solution containing cytochrome c could cause the decrease of the redox peaks of the protein, and the peaks could be recovered when Ca2+ was chelated by ethylenediaminetetraacetate. The cardiolipin–cytochrome c interaction and the Ca2+ effect were also investigated with the variation of the charges of lipids, buffer solutions, reaction time, and valencies of cations for comparison. 相似文献
10.
Seyed Abdollah Mousavi Janina Österman Niklas Wahlberg Xavier Nesme Céline Lavire Ludovic Vial Lars Paulin Philippe de Lajudie Kristina Lindström 《Systematic and applied microbiology》2014
The genera Agrobacterium, Allorhizobium, and Rhizobium belong to the family Rhizobiaceae. However, the placement of a phytopathogenic group of bacteria, the genus Agrobacterium, among the nitrogen-fixing bacteria and the unclear position of Rhizobium galegae have caused controversy in previous taxonomic studies. To resolve uncertainties in the taxonomy and nomenclature within this family, the phylogenetic relationships of generic members of Rhizobiaceae were studied, but with particular emphasis on the taxa included in Agrobacterium and the “R. galegae complex” (R. galegae and related taxa), using multilocus sequence analysis (MLSA) of six protein-coding housekeeping genes among 114 rhizobial and agrobacterial taxa. The results showed that R. galegae, R. vignae, R. huautlense, and R. alkalisoli formed a separate clade that clearly represented a new genus, for which the name Neorhizobium is proposed. Agrobacterium was shown to represent a separate cluster of mainly pathogenic taxa of the family Rhizobiaceae. A. vitis grouped with Allorhizobium, distinct from Agrobacterium, and should be reclassified as Allorhizobium vitis, whereas Rhizobium rhizogenes was considered to be the proper name for former Agrobacterium rhizogenes. This phylogenetic study further indicated that the taxonomic status of several taxa could be resolved by the creation of more novel genera. 相似文献
11.
Narayanan Sathiya Pandi Muthaiah ManimuthuPalaniswamy Harunipriya Manikandan MurugesanGeorge Virumaandi Asha Suriliyandi Rajendran 《Gene》2014
Actin-binding protein anillin (ANLN) is primarily involved in the cytokinesis and known to be dysregulated in many cancers including gastric cancer (GC). However, the regulation and clinical significance of ANLN in GC are far less clear. In the present study, we aimed to investigate the clinical significance and possible regulators of ANLN in GC. We have identified the Wnt/β-catenin associated regulation of ANLN by analyzing the in vitro perturbed β-catenin mRNA expression profiles. Investigating the gastric tumors from publicly available genome-wide mRNA expression profiles, we have identified the over expression of ANLN in gastric tumors. Association between ANLN expression and clinical characteristics of GC showed elevated expression in intestinal type GC. Performing a single sample prediction method across GC mRNA expression profiles, we have identified the over expression of ANLN in proliferative type gastric tumors compared to the invasive and metabolic type gastric tumors. In silico pathway prediction analysis revealed the association between Wnt/β-catenin signaling and ANLN expression in gastric tumors. Our results highlight that expression of a Wnt/β-catenin responsive gene ANLN in GC is a molecular predictor of intestinal and proliferative type gastric tumors. 相似文献
12.
Xiaomao Zeng Jinzhong Fu Liqiao Chen Yingzhou Tian Xiaohong Chen 《Biochemical Systematics and Ecology》2006
Using mitochondrial DNA sequencing and allozyme electrophoresis, we examined 18 populations of the Liua–Pseudohynobius complex, endemic to China. Based on their phylogenetic affiliation and exhibited fixed allelic differences, the complex comprises at least six species, two of which are previously unknown cryptic species. The complex is clearly divided into two groups, genus Liua including Liua shihi and Liua tsinpaensis, and genus Pseudohynobius including Pseudohynobius flavomaculatus, Pseudohynobius shuichengensis and the two new species. The previously often used genus name Ranodon is inappropriate, because the type species of the genus, Ranodon sibricus, is distantly related to this complex. The species diversity among Chinese hynobiid salamanders are far from being recognized and further effort should be directed at extensive field collection in central and western China. 相似文献
13.
Renchao Zhou Suo QiuMeng Zhang Miaomiao GuoSufang Chen Suhua Shi 《Biochemical Systematics and Ecology》2010
It is expected that geographically widespread and outcrossing tree species would have high level of genetic variation. Three chloroplast regions and six nuclear genes were sequenced to assess the genetic variation of a species of mangroves, Sonneratia ovata, from China and Thailand. No nucleotide polymorphism was found in the three chloroplast regions and in the six nuclear genes from all of the four populations examined. The depauperation of polymorphism in S. ovata in comparison to moderate polymorphisms of other congeneric species is surprising, particularly considering high level of polymorphism in the past and relatively wide geographic distribution of the species. Since multiple independent loci were surveyed in this study, the most plausible explanation for our observation is that S. ovata has experienced severe demographic bottlenecks in the Pleistocene glaciation, followed by subsequent recolonization by sea currents in China and Southeast Asia regions. The lack of polymorphism may also be attributable to its small population size, despite its wide geographic distribution. 相似文献
14.
β-Glucosyl esters of A-ring oxygenated 19α-hydroxyursolic acids were isolated from the leaves of Rubus microphyllus, R. koehneanus, R. trifidus and R. medius. Comparisons of the glycoside fractions of the leaves of 39 Rubus species were conducted, indicating the chemotaxonomic significance of this type of glucosyl ester in this genus. 相似文献
15.
Harald John Michael Eddleston R. Eddie Clutton Franz Worek Horst Thiermann 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(17-18):1234-1245
Dimethoate is an organophosphorus toxicant used in agri- and horticulture as a systemic broad-spectrum insecticide. It also exhibits toxic activity towards mammalian organism provoked by catalytic desulfuration in the liver producing its oxon-derivative omethoate thus inhibiting acetylcholinesterase, initiating cholinergic crisis and ultimately leading to death by respiratory paralysis and cardiovascular collapse. Pharmaco- and toxicokinetic studies in animal models help to broaden basic understanding of medical intervention by antidotes and supportive care. Therefore, we developed and validated a LC–ESI-MS/MS method suitable for the simultaneous, selective, precise (RSDintra-day 1–8%; RSDinter-day 5–14%), accurate (intra-day: 95–107%; inter-day: 90–115%), and robust quantification of both pesticides from porcine urine and plasma after deproteinization by precipitation and extensive dilution (1:11,250 for plasma and 1:40,000 for urine). Accordingly, lower limits of quantification (0.24–0.49 μg/ml plasma and 0.78–1.56 μg/ml urine) and lower limits of detection (0.12–0.24 μg/ml plasma and 0.39–0.78 μg/ml urine) were equivalent to quite low absolute on-column amounts (1.1–2.1 pg for plasma and 2.0–3.9 pg for urine). The calibration range (0.24–250 μg/ml plasma and 0.78–200 μg/ml urine) was subdivided into two linear ranges (r2 ≥ 0.998) each covering nearly two orders of magnitude. The lack of any interfering peak in 6 individual blank specimens from plasma and urine demonstrated the high selectivity of the method. Furthermore, extensive sample dilution causing lowest concentration of potentially interfering matrix ingredients prompted us to develop and validate an additional flow-injection method (FI-ESI-MS/MS). Validation characteristics were as good as for the chromatographic method but sample throughput was enhanced by a factor of 6. Effects on ionization provoked by plasma and urine matrix from 6 individuals as well as in the presence of therapeutics (antidotes) administered in an animal study were investigated systematically underling in the reliability of the presented methods. Both methods were applied to porcine samples derived from an in vivo animal study. 相似文献
16.
Jing-Ze Zhang Wen-Yuan Gao Ying Gao Dai-Lin Liu Lu-Qi Huang 《Acta Physiologiae Plantarum》2011,33(6):2511-2520
Focusing on the variations of chemical constituents in licorice root, influences of exposure to physical factors of spaceflight
on licorice (Glycyrrhiza uralensis Fisch.) seeds were investigated. Licorice seeds obtained from two different producing areas were flown on a recoverable satellite
for 18 days. After returning to earth, the seeds carried by the satellite and the parallel ground control were cultivated
to maturity under the same condition. Chromatographic fingerprint of 1 year licorice root analyzed by high performance liquid
chromatography with diode-array detection not only displayed the contents of glycyrrhizic acid and liquiritin increasing in
the spaceflight samples but showed the variation of the kinds of chemical constituents. The main components in the root extract
were identified by high performance liquid chromatography coupled with electrospray ionization multi-tandem mass spectrometry.
The changes in the kind of secondary metabolites of licorice root after spaceflight were firstly reported. A total of 26 components
which included 9 flavonoids, 16 triterpene saponins and 1 coumarin were identified according to their mass spectra determined
in both negative and positive ion modes. The research provided the scientific data for spaceflight breeding of medicinal plant
and indicated that the technology of spaceflight may be a new effective method for the breeding and cultivation of licorice. 相似文献
17.
Paola Manini Roberta Andreoli Stefano Sforza Chiara Dall’Asta Gianni Galaverna Antonio Mutti Wilfried M.A. Niessen 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(27):2616-2622
We present the application of a novel isotope dilution method, named Alternate Isotope-Coded Derivatization Assay (AIDA), to the quantitative analysis of hydrazone derivatives of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) in exhaled breath condensate (EBC) samples using liquid chromatography–tandem mass spectrometry. AIDA is based on the alternate derivatization of the analyte(s) with reagents that are available in two pure isotopic forms, respectively “light” and “heavy”, by using light-derivatized standards for the quantification of the heavy-derivatized analytes, and vice versa. To this purpose, 2,4-dinitro-3,5,6-trideuterophenylhydrazine (d3-DNPH) has been synthesized and used as “heavy” reagent in combination with commercial “light” DNPH. Using the AIDA method, any unknown concentration of the analyte in the matrix can be calculated without the need of a calibration curve. An external calibration method has been also investigated for comparative purpose. The stability of DNPH and d3-DNPH derivatives was verified by excluding any exchange of hydrazones with each other. In the range of concentrations of biological interest, e.g., 2–40 nM for MDA and 0.5–10 nM for 4-HNE, the derivatization reactions of MDA and 4-HNE with DNPH and d3-DNPH showed overlapping kinetics and comparable yields. The MS response of both DNPH and d3-DNPH hydrazones was similar. The precision of AIDA, calculated as %RSD, was within 3.2–8% for MDA and 4.5–11% for 4-HNE. Accuracy was tested by analyzing a spiked EBC pool sample and acceptable results (accuracy within 98–108% for MDA and 93–114% for 4-HNE) were obtained by AIDA after subtraction of the blank, which was not negligible. The results of quantitative analysis of MDA and 4-HNE in EBC samples obtained by AIDA assay with four analyses per sample were in good agreement with those obtained by external calibration method on the same samples. 相似文献
18.
The sterols and triterpenoids of 12 species of the genus Ononis were analysed by GLC. α-Onocerin was found in all but one of these species, although in some others its concentration was low. In all species examined, sitosterol was the major sterol; stigmasterol, campesterol, cholesterol and the triterpenoids cycloartenol and 24-methylene cycloartanol also occurred. The patterns of α-onocerin and sterols found seem to be consistent with the accepted classification of species within the genus. 相似文献
19.
The main aim of presented study was the comparison of various extraction methods for the quantitative and qualitative analysis (LC-ESI–MS/MS) of phenolic acids present in extracts obtained from leaves, flowers, and roots of Impatiens glandulifera. The accelerated solvent extraction (ASE) at three temperature ranges (80° C, 100° C, and 120° C), ultrasound assisted extraction (USAE) at 60° C, and traditional extraction in Soxhlet apparatus were used. Taking into account the extraction yield, and the diversity of the individual compounds, ultrasound assisted extraction proved to be the most efficient method, and it was used to determine the content of phenolic acids in leaves of four other Impatiens species, including I. balsamina, I. noli-tangere, I. parviflora, and I. walleriana. Eleven phenolic acids were identified in all examined species. These were protocatechuic, gentisic, 4- hydroxybenzoic, vanillic, trans-caffeic, syringic, trans-p-coumaric, trans- and cis-ferulic, salicylic, and 3-hydroxycinnamic acids. In the extract from the leaves of I. balsamina and I. walleriana, gallic and cis-p-coumaric acids were found additionally. The most abundant compounds in all examined extracts were protocatechuic and 3-hydroxycinnamic acids. The latest acid was found in the highest yield in I. noli-tangere (266.12 μg/g DW). In the leaves of I. glandulifera a great amount of 4-hydroxybenzoic (41.44 μg/g DW), vanillic (61.50 μg/g DW), and trans-p-coumaric (58.42 μg/g DW) acids was also observed. Our results indicate that protocatechuic, 4-hydroxybenzoic, vanillic, trans-p-coumaric, trans-ferulic, and 3-hydroxycinnamic acids were most characteristic of Impatiens species.Additionally, various phenolic-rich extracts from leaves, flowers, and roots of Impatiens glandulifera were tested for antioxidant activity. The highest antiradical activity was detected for roots using Soxhlet extraction (EC50 = 0.055 mg [DE/ml]).The study demonstrated that members of the genus Impatiens, and in particular Impatiens glandulifera, and Impatiens noli-tangere, contain significant amounts of phenolic acids. In addition, extracts from various parts of I. glandulifera could be interesting as novel sources of natural antioxidants. 相似文献
20.
Hans von Stedingk Per Rydberg Margareta Törnqvist 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(27):2483-2490
A rapid and sensitive method using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for simultaneous determination of adducts from acrylamide, glycidamide and ethylene oxide to N-terminal valines in hemoglobin (Hb) was developed. This new procedure is based on the same principles as the N-alkyl Edman procedure for analysis of adducts from electrophilic agents to N-terminal valines in Hb. The N-substituted valines can be detached, enriched and measured selectively as thiohydantoins by the use of an Edman reagent, in this case fluorescein isothiocyanate (FITC). This procedure is denoted as the “adduct FIRE procedure” as the FITC reagent is used for measurement of adducts (R) formed from electrophilic compounds with a modified Edman procedure. In this study, fluorescein thiohydantoin (FTH) analytes of N-substituted valines from acrylamide, glycidamide and ethylene oxide, as well as their corresponding hepta- and tri-deuterium-substituted analogues, were synthesized. These analytes (n = 8) were then characterized by LC–MS/MS (ESI, positive ion mode) and obtained product ions were interpreted. A considerable work with optimization of the FIRE procedure™, resulted in a procedure in which low background levels of the studied adducts could be measured from 250 μL lyzed whole blood samples (human non-smokers). The analytes were enriched and purified with solid phase extraction columns and analyzed by LC–MS/MS with LOQ down to 1 pmol adduct/g Hb. Compared to other procedures for determination of N-terminal Hb adducts, the introduction of FITC has led to a simplified procedure, where whole blood also can be used, giving new opportunities and reduced hand on time with increased sample throughput. 相似文献