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1.
Brevibacillus brevis HOB1 was isolated from the formation water of an oil field and found to produce lipopeptides. The separation of lipopeptides was successfully achieved by reversed-phase high-performance liquid chromatography (HPLC) leading to nine separated peaks. The chemical structures of these lipopeptides were studied by means of electrospray ionization mass spectrometry (ESI-MS), gas chromatography-mass spectrometry (GC/MS), HPLC and electrospray ionization tandem mass spectrometry (ESI-MS/MS). As the results, all the lipopeptides had peptide parts with the same amino acid composition of Asp, Glu, Val, and Leu in the molar ratio 1:1:1:4, while the lipid part was composed of C13–C15 β-hydroxy fatty acids. As the sequence of fraction 1 was determined to be N-Glu-Leu-Leu-Val-Asp-Leu-Leu-C, the same as surfactin, they were proposed to be surfactin isoforms. Fraction 4 (C15 surfactin) exhibited a good surface activity of 26.8 mN/m with CMC of 9?×?10?6 M. Surfactin is a powerful biosurfactant possessing biological activities. As far as we know, Br. brevis is a new surfactin-producing species.  相似文献   

2.
《Analytical letters》2012,45(6):929-940
Surfactin and lichenysin are typical members of the lipopeptide family. Four surfactin and two lichenysin isoforms were isolated by Pre RP-HPLC from the cell-free broth of Bacillus licheniformis HSN 221 cultivated in YPD medium. The molecular weight of each isoform was determined by ESI-MS. The peptide part of each isoform was elucidated by Q-Tof MS/MS combined with HPLC, and the fatty acid part was analyzed by GC/MS. It showed that the four surfactin isoforms have the primary structures of anteiso(iso)C13, isoC14, anteiso(iso)C15, anteiso(iso)C15-surfactin-methyl ester, and the two lichenysin isoforms have those of nC14 and anteiso(iso)C15, respectively.  相似文献   

3.
In this study, thirty-eight isoflavone derivatives were comprehensively identified and quantified from the raw, steamed and fermented seeds of four selected soybean cultivars based on UPLC-DAD-QToF/MS results with reference to the previously reported LC-MS library and flavonoid database, and summarized by acylated group including glucosides (Glu), malonyl-glucosides (Mal-Glu), acetyl-glucosides (Ac-Glu), succinyl-glucosides (Suc-Glu) and phosphorylated conjugates (Phos) in addition to aglycones. Among them, Suc-Glu and Phos derivatives were newly generated due to fermentation by B. subtilis AFY-2 (cheonggukjang). In particular, Phos were characterized for the first time in fermented soy products using Bacillus species. From a proposed roadmap on isoflavone-based biotransformation, predominant Mal-Glu (77.5–84.2%, raw) decreased rapidly by decarboxylation and deesterification into Ac-Glu and Glu (3.5–8.1% and 50.0–72.2%) during steaming, respectively. As fermentation continued, the increased Glu were mainly succinylated and phosphorylated as well as gradually hydrolyzed into their corresponding aglycones. Thus, Suc-Glu and Phos (17.3–22.4% and 1.5–5.4%, 36 h) determined depending on cultivar type and incubation time, and can be considered as important biomarkers generated during cheonggukjang fermentation. Additionally, the changes of isoflavone profile can be used as a fundamental report in applied microbial science as well as bioavailability research from fermented soy foods.  相似文献   

4.
Lipopeptide biosurfactants produced by the Bacillus licheniformis V9T14 strain showed an interesting anti‐adhesion activity against biofilm formation of human pathogenic bacterial strains. The chemical characterisation of the crude extract of V9T14 strain was first developed through electrospray ionisation mass spectrometry (ESI‐MS) and ESI‐MS/MS direct infusions: two sets of molecular ion species belonging to the fengycin and surfactin families were revealed and their structures defined, interpreting their product ion spectra. The LC/ESI‐MS analysis of the crude extract allowed to separate in different chromatogram ranges the homologues and the isoforms of the two lipopeptide families. The extract was then fractionated by silica gel chromatography in two main fractions, I and II. The purified biosurfactants were analysed through a new, rapid and suitable LC/ESI‐MS/MS method, which allowed characterising the composition and the structures of the produced lipopeptides. LC/ESI‐MS/MS analysis of fraction I showed the presence of C13, C14 and C15 surfactin homologues, whose structures were confirmed by the product ion spectra of the sodiated molecules [M + Na]+ at m/z 1030, 1044 and 1058. LC/ESI‐MS/MS analysis of fraction II confirmed the presence of two main fengycin isoforms, with the protonated molecules [M + H]+ at m/z 1478 and 1506 corresponding to C17 fengycin A and C17 fengycin B, respectively. Other homologues (C14 to C16) were revealed and confirmed as belonging to fengycin A or B according to the retention times and the product ions generated, although with the same nominal mass. Finally, a relative percentage content of each homologue for both lipopeptides families in the whole extract was proposed. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

5.
In order to avoid foaming behavior and the formation of stable emulsions in traditional extraction, non-dispersive extraction of surfactin from the fermentation broth of Bacillus subtilis ATCC 21332 culture with n-hexane was studied in microporous polyvinylidene fluoride (PVDF, pore size 0.2 μm) hollow fiber module. In this work, the broth was pretreated by acid precipitation and the precipitate was then dissolved in NaOH solution, and the treated broth was passed through the lumen side of the module and n-hexane was flowed across the shell side. Experiments were performed at a fixed pH of 8.0 and a flow rate of both phases of 2.5 mL min−1 but at different surfactin concentrations (300–3000 mg L−1). Under the conditions studied, it was shown that surfactin was adsorbed onto the surface of the fibers, instead of being extracted by n-hexane and transported through the pores of the fibers into bulk n-hexane phase. The adsorption capacity was determined and the adsorption dynamics was analyzed. The purity of surfactin desorbed from the fibers with ethanol was found to be higher than that obtained after solvent extraction with n-hexane.  相似文献   

6.
Capillary zone electrophoresis (CZE) with electrospray ionization (ESI) mass spectrometry (MS) was used to study borate (B?1) and sugar (L) complexes (L x B?1). Boric acid was adjusted to pH 10 with ammonium hydroxide to create an ESI-MS compatible CZE background electrolyte. We show for the first time that the electrophoretic peaks for each injected sugar contained both the substrates (i.e., sugar and/or multimers) and products (i.e., L x B?1). The effects of sheath liquid, temperature, and borate concentration were studied. The molecular mass information obtained from the ESI-MS provided new evidence on the mechanisms of borate-sugar complexation. Direct infusion ESI-MS and CZE-ESI-MS experiments strongly suggest that the formation of L x B?1 was from the direct reaction of a sugar or sugar multimer (L x ) and B?1. Larger L x B?1, where x > 2 were observed. Separation in the CZE dimension allows for the simultaneous analysis of a sugar mixture and simplified the ESI-MS analysis of sugars of the same molecular mass. The increase in sugar electrophoretic mobility caused by the increase in borate concentration was discussed in terms of the formation of L x B?1 complexes. In addition, the separation of five nucleosides by CZE using a borate electrolyte and detection using ESI-MS is demonstrated.  相似文献   

7.
Cucurbita moschata Duchesne (Cucurbitaceae) is a plant food highly appreciated for the content of nutrients and bioactive compounds, including polyphenols and carotenoids, which contribute to its antioxidant and antimicrobial capacities. The purpose of this study was to identify phenolic acids and flavonoids of Cucurbita moschata Duchesne using high-performance liquid chromatography–diode array detection–electrospray ionization tandem mass spectrometry (HPLC–DAD–ESI-MS) at different ripening stages (young, mature, ripened) and determine its antioxidant and antimicrobial activities. According to the results, phenolic acids and flavonoids were dependent on the maturity stage. The mature fruits contain the highest total phenolic and flavonoids contents (97.4 mg GAE. 100 g−1 and 28.6 mg QE. 100 g−1).A total of 33 compounds were identified. Syringic acid was the most abundant compound (37%), followed by cinnamic acid (12%) and protocatechuic acid (11%). Polyphenol extract of the mature fruits showed the highest antioxidant activity when measured by DPPH (0.065 μmol TE/g) and ABTS (0.074 μmol TE/g) assays. In the antimicrobial assay, the second stage of ripening had the highest antibacterial activity. Staphylococcus aureus was the most sensitive strain with an inhibition zone of 12 mm and a MIC of 0.75 mg L−1. The lowest inhibition zone was obtained with Salmonella typhimurium (5 mm), and the MIC value was 10 mg L−1.  相似文献   

8.
The electrospray tandem mass spectra (ESI-MS/MS) of the three N,N′-bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines 1–3 displayed the same fragment-ion signals. These isomers could not be differentiated by ESI-MS/MS, since their fragmentation patterns are similar. (E,E)-N-(3-[15N]Aminopropyl)-3,3′-bis(4- hydroxyphenyl)-N,N′-(butane-1,4-diyl)bis[prop-2-enamide] ([15N(1)])-( 1 ) was synthesized in order to get further information about the fragmentation mechanisms. The comparison of the ESI-MS/MS of 1 and [15N(1)]- 1 revealed a transamidation, the Zip reaction, under mass-spectral conditions of the [ 1 + H]+ ions. Because of this reaction, the three isomers 1–3 could not be distinguished.  相似文献   

9.
Bacillus subtilis LAMI008 strain isolated from the tank of Chlorination at the Wastewater Treatment Plant on Campus do Pici in Federal University of Ceará, Brazil has been screened for surfactin production in mineral medium containing clarified cashew apple juice (MM-CAJC). Results were compared with the ones obtained using mineral medium with glucose PA as carbon source. The influence on growth and surfactin production of culture medium supplementation with yeast extract was also studied. The substrate concentration analysis indicated that B. subtilis LAMI008 was able to degrade all carbon sources studied and produce biosurfactant. The highest reduction in surface tension was achieved with the fermentation of MM-CAJC, supplemented with yeast extract, which decreased from 58.95?±?0.10 to 38.10?±?0.81 dyn cm?1. The biosurfactant produced was capable of emulsifying kerosene, achieving an emulsification index of 65%. Surfactin concentration of 3.5 mg L?1 was obtained when MM-CAJC, supplemented with yeast extract, was used, thus indicating that it is feasible to produce surfactin from clarified cashew apple juice, a renewable and low-cost carbon source.  相似文献   

10.
L-glutaminase is an important anticancer agent that is used extensively worldwide by depriving cancer cells of L-glutamine. The marine bacterium, Halomonas meridian was isolated from the Red Sea and selected as the more active L-glutaminase-producing bacteria. L-glutaminase fermentation was optimized at 36 h, pH 8.0, 37 °C, and 3.0% NaCl, using glucose at 1.5% and soybean meal at 2%. The purified enzyme showed a specific activity of 36.08 U/mg, and the molecular weight was found to be 57 kDa by the SDS-PAGE analysis. The enzyme was highly active at pH 8.0 and 37 °C. The kinetics’ parameters of Km and Vmax were 12.2 × 10−6 M and 121.95 μmol/mL/min, respectively, which reflects a higher affinity for its substrate. The anticancer efficiency of the enzyme showed significant toxic activity toward colorectal adenocarcinoma cells; LS 174 T (IC50 7.0 μg/mL) and HCT 116 (IC50 13.2 μg/mL). A higher incidence of cell death was observed with early apoptosis in HCT 116 than in LS 174 T, whereas late apoptosis was observed in LS 174 T more than in HCT 116. Also, the L-glutaminase induction nuclear fragmentation in HCT 116 was more than that in the LS 174T cells. This is the first report on Halomonas meridiana as an L-glutaminase producer that is used as an anti-colorectal cancer agent.  相似文献   

11.
In this work, 53 selected pesticides of different chemical groups were extracted from Chinese herbal medicines and determined by ultra-high-performance liquid chromatography (UHPLC)–tandem mass spectrometry (MS/MS) using both electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI). Extracts were obtained using the acetonitrile-based quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation technique. Cleanup was performed by dispersive solid-phase extraction using primary secondary amine, graphitized carbon black, and octadecylsilane. Two atmospheric-pressure interfaces, ESI and APCI, were checked and compared. The validation study, including detection limits, linearity, and matrix effects, was conducted on fritillaria, radix ginseng, folium isatidis, semen persicae, and flos lonicerae in multiple reaction monitoring mode. These matrices represent a variety of plants used in traditional Chinese medicine. Fritillaria and radix ginseng were chosen as representatives for roots, folium isatidis was chosen as a representative for leaves, semen persicae was chosen as a representative for seeds, and flos lonicerae was chosen as a representative for flowers. The limits of detection for pesticides were lower in the UHPLC–ESI-MS/MS method than in the UHPLC–APCI-MS/MS method. Matrix effects on the two ionizations were evaluated for the five matrices. Soft signal enhancement in UHPLC–APCI-MS/MS and signal suppression in UHPLC–ESI-MS/MS were observed.
Figure
Overview of UPLC–MS/MS assay for comparing the APCI and ESI interfaces  相似文献   

12.
A new alkaloid, geissospermiculatine was characterized in Geissospermum reticulatum A. H. Gentry bark (Apocynaceae). Here, following a simplified isolation protocol, the structure of the alkaloid was elucidated through GC-MS, LC-MS/MS, 1D, and 2D NMR (COSY, ROESY, HSQC, HMBC, 1H-15N HMBC). Cytotoxic properties were evaluated in vitro on malignant THP-1 cells, and the results demonstrated that the cytotoxicity of the alkaloid (30  μg/mL) was comparable with staurosporine (10  μM). Additionally, the toxicity was tested on zebrafish (Danio rerio) embryos in vivo by monitoring their development (0–72 h); toxicity was not evident at 30  μg/mL.  相似文献   

13.
《Electrophoresis》2018,39(2):334-343
Differential proteomics targeting the protein abundance is commonly used to follow changes in biological systems. Differences in localization and degree of post‐translational modifications of proteins including phosphorylations are of tremendous interest due to the anticipated role in molecular regulatory processes. Because of their particular low abundance in prokaryotes, identification and quantification of protein phosphorylation is traditionally performed by either comparison of spot intensities on two‐dimensional gels after differential phosphoprotein staining or gel‐free by stable isotope labeling, sequential phosphopeptide enrichment and following LC‐MS analysis. In the current work, we combined in a proof‐of‐principle experiment these techniques using 14N/15N metabolic labeling with succeeding protein separation on 2D gels. The visualization of phosphorylations on protein level by differential staining was followed by protein identification and determination of phosphorylation sites and quantification by LC‐MS/MS. This approach should avoid disadvantages of traditional workflows, in particular the limited capability of peptide‐based gel‐free methods to quantify isoforms of proteins. Comparing control and stress conditions allowed for relative quantification in protein phosphorylation in Bacillus pumilus exposed to hydrogen peroxide. Altogether, we quantified with this method 19 putatively phosphorylated proteins.  相似文献   

14.
In this study, methanol extracts (MEs) and essential oil (EO) of Angelica purpurascens (Avé-Lall.) Gill obtained from different parts (root, stem, leaf, and seed) were evaluated in terms of antioxidant activity, total phenolics, compositions of phenolic compound, and essential oil with the methods of 2,2-azino-bis(3ethylbenzo-thiazoline-6-sulfonic acid (ABTS•+), 2,2-diphenyl-1-picrylhydrazil (DPPH•) radical scavenging activities, and ferric reducing/antioxidant power (FRAP), the Folin–Ciocalteu, liquid chromatography−tandem mass spectrometry (LC−MS/MS), and gas chromatography-mass spectrometry (GC−MS), respectively. The root extract of A. purpurascens exhibited the highest ABTS•+, DPPH•, and FRAP activities (IC50: 0.05 ± 0.0001 mg/mL, IC50: 0.06 ± 0.002 mg/mL, 821.04 ± 15.96 µM TEAC (Trolox equivalent antioxidant capacity), respectively). Moreover, EO of A. purpurascens root displayed DPPH• scavenging activity (IC50: 2.95 ± 0.084 mg/mL). The root extract had the highest total phenolic content (438.75 ± 16.39 GAE (gallic acid equivalent), µg/mL)). Twenty compounds were identified by LC−MS/MS. The most abundant phenolics were ferulic acid (244.39 ± 15.64 μg/g extract), benzoic acid (138.18 ± 8.84 μg/g extract), oleuropein (78.04 ± 4.99 μg/g extract), and rutin (31.21 ± 2.00 μg/g extract) in seed, stem, root, and leaf extracts, respectively. According to the GC−MS analysis, the major components were determined as α-bisabolol (22.93%), cubebol (14.39%), α-pinene (11.63%), and α-limonene (9.41%) among 29 compounds. Consequently, the MEs and EO of A. purpurascens can be used as a natural antioxidant source.  相似文献   

15.
Electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS) have been used to differentiate the 2- and 4-methylpyridyl isomers of free-base and metallated cationic beta-vinylpyridylporphyrins. The analysis by ESI-MS/MS of the deuterated analogs and semiempirical calculations of structural and electronic parameters were also undertaken. The two free-base isomers are easily differentiated by ESI-MS/MS but the presence of a metallic center renders differentiation of the metallated isomers less effective. The data acquired show that of all the studied compounds, the free-base 2-methylpyridyl isomer, which was operative in the in vitro photoinactivation of Herpes simples virus, has a different gas-phase behavior. Local distortion of the macrocycle due to the presence of the beta-vinylpyridyl substituent occurs for all the compounds, but a different electron density distribution can account for the observed gas-phase behavior of this potential virus photoinactivator.  相似文献   

16.
Several penta- and hexa-substituted aryloxycyclotriphosphazenes were synthesized and investigated by electrospray ionization tandem mass spectrometry (ESI-MSn). Their main fragmentation pathways are proposed based on the MSn and accurate mass data. An apparent hydrolysis reaction is an important fragmentation process exhibited in the ESI-MS/MS spectra for all of them. Also interesting is the intramolecular electrocyclic ring closure observed in ESI-MS/MS spectra of them. These observations may have some potential applications in the distinction between the mass spectra of penta- and hexa-substituted hexachlorocyclotriphosphazene derivatives.  相似文献   

17.
A method of determination of 32 carbonyl compounds by high performance liquid chromatography (HPLC) and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) after derivatization with 2,4-dinitrophenylhydrazine (DNPH) was developed and successfully applied to the atmosphere sample of a residential area of Liwan District (S1) and a research institute of Tianhe District (S2) in Guangzhou, China. Some operation conditions of ESI-MS/MS in the negative ion mode including selection of parent and daughter ions, declustering potential (DP), entrance potential (EP), collision energy (CE), collision cell exit potential (CXP) and effect of buffer in ESI-MS/MS process were optimized. The regression coefficient of the calibration curves (R2), recovery, reproducibility (R.S.D., n = 5) and limit of detection (LOD) were in the range of 0.9938-0.9999, 90-104%, 1.7-11% and 0.4-9.4 ng/m3, respectively. Among most of the samples, acetone was the most abundant carbonyl in two sampling sites and formaldehyde, acetaldehyde and butyraldehyde/2-butanone were also abundant carbonyls. In contrast to LC-UV method, the LOD, the separation of some co-eluting compounds and the precision (mainly to higher molecular weight carbonyls) are all improved by LC-ESI-MS/MS.  相似文献   

18.
High-throughput identification and quantification of protein/peptide biomarkers from biofluids in a label-free manner is achieved by interfacing bio-affinity arrays (BAAs) with nano-electrospray desorption electrospray ionization mass spectrometry (nano-DESI-MS). A wide spectrum of proteins and peptides ranging from phosphopeptides to cis-diol biomolecules as well as thrombin can be rapidly extracted via arbitrarily predefined affinity interactions including coordination chemistry, covalent bonding, and biological recognition. An integrated MS platform allows continuous interrogation. Profiling and quantitation of dysregulated phosphopeptides from small-volume (∼5 μL) serum samples has been successfully demonstrated. As a front-end device adapted to any mass spectrometer, this MS platform might hold much promise in protein/peptide analysis in point-of-care (POC) diagnostics and clinical applications.

Customizable bio-affinity arrays were interfaced with ambient ionization mass spectrometry for high-throughput assays of protein/peptide biomarkers in biofluids.  相似文献   

19.
The novel asymmetric metallo-organic triads cis- and trans-[B(4-py)BPFPH2{Ru3O(Ac)6(py)2}{Ru(bpy)2Cl}](PF6)2 (5a,b) for which cis- and trans-B(4-py)BPFPH2 = 5,10-bis(pentafluorophenyl)-15,20-bis(4-pyridyl)porphyrin and 5,15-bis(pentafluorophenyl)-10,20-bis(4-pyridyl)porphyrin, respectively; Ac = acetate; py = pyridine and bpy = 2,2′-bipyridine, as well as their corresponding monosubstituted dyads cis- and trans-[B(4-py)BPFPH2{Ru3O(Ac)6(py)2}]PF6 (4a,b) have been structurally characterized via electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS). The ESI-MS of dyads 4a,b display two characteristic Ru-multicomponent clusters of isotopologue ions corresponding to singly charged ions 4a,b+ of m/z 1629 and doubly charged ions [4a,b+H]2+ of m/z 815 and the triads 5a,b are detected by ESI-MS as the intact doubly charged cluster of isotopologue ions of m/z 1039 [5a,b]2+. The ESI-MS/MS of 4a,b+, [4a,b+H]2+ and [5a,b]2+ reveal characteristic dissociation pathways, which confirm the structural assignments providing additional information on the intrinsic binding strengths of the gaseous ions. Although the gas-phase behavior of each pair of isomers was rather similar, the less symmetric dyads 4a,b are distinguished via the 1H NMR spectral profile of the pyrrolic signals. Exploratory photophysical assays have shown that both modifying motifs alter the porphyrinic core emission profile, opening the possibility to use these asymmetric systems as photophysical devices.  相似文献   

20.
The distribution of pharmatically important alkaloids gelsemine, koumine, and gelsenicine in Gelsemium elegans tissues is a hot topic attracting research attention. Regretfully, the in planta visual distribution details of these alkaloids are far from clear although several researches reported the alkaloid quantification in G. elegans by LC-MS/MS. In this study, mass imaging spectrometry (MSI) was employed to visualize the in situ visualization of gelsemine, koumine, and gelsenicine in different organs and tissues of G. elegans at different growth stages, and the relative quantification of three alkaloids were performed according to the image brightness intensities captured by the desorption electrospray ionization MSI (DESI-MSI). The results indicated that these alkaloids were mainly accumulated in pith region and gradually decreased from pith to epidermis. Interestingly, three alkaloids were found to be present in higher abundance in the leaf vein. Along with the growth and development, the accumulation of these alkaloids was gradually increased in root and stem. Moreover, we employed LC-MS/MS to quantify three alkaloids and further validated the in situ distributions. The content of koumine reached 249.2 μg/g in mature roots, 272.0 μg/g in mature leaves, and 149.1 μg/g in mature stems, respectively, which is significantly higher than that of gelsemine and gelsenicine in the same organ. This study provided an accurately in situ visualization of gelsemine, koumine, and gelsenicine in G. elegans, and would be helpful for understanding their accumulation in plant and guiding application.  相似文献   

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