ANALYTICAL CHEMISTRY
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2016
·
IF 5.886
Li Cui,Ying-Jiao Zhang,Wei E. Huang,Bi-Feng Zhang,Francis L. Martin,Jun-Yi Li,Kai-Song Zhang,Yong-Guan Zhu
Bacterial antibiotic resistance poses a threat to global public health. Restricted usage of antibiotics does not necessarily prevent its continued emergence. Rapid and sensitive screening of triggers, in addition to antibiotic, and exploring the underlying mechanism are still major challenges. Herein, by developing a homogeneous vacuum filtration-based bacterial sample fabrication enabling high surface-enhanced Raman scattering (SERS) reproducibility across multiple bacterial samples and negating interfering spectral variations from inhomogeneous sample geometry and SERS enhancement, SERS was employed to study heavy metal arsenic [As(V)]-mediated antibiotic resistance in a robust, sensitive, and rapid fashion. Independent and robust spectral changes representing phenotypic bacterial responses, combined with multivariate analysis, clearly identified that As(V) enhanced antibiotic resistance to tetracycline (Tet). Similar spectral alteration profile to As(V) and Tet indicated that cross-resistance, whereby As(V)-induced bacterial resistance simultaneously blocked Tet action, could account for the enhanced resistance. The sensitive, robust, and rich phenotypic profile provided by SERS, combined with additional advantages in imposing no need to cultivate bacteria and single-cell sensitivity, can be further exploited to evaluate resistance-intervening factors in real microbiota.
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TALANTA
·
2016
·
IF 4.035
Huihui Li,Ting Cheng,Shuxia Wang,Xinyue Zhu,Haixia Zhang
Boronate affinity materials have been widely used for selective capture of cis-diol-containing molecules, but most do not have sufficient extraction efficiency. We have prepared boronic acid-functionalized attapulgite, and then it was coated with imidazolium-based ionic liquid , 1-dodecyl-3-methylimidazolium bromide (C 12 mimBr), via physical self-assembly process. The extraction efficiency of the material increased dramatically after coated with C 12 mimBr, and its enrichment ratios for nucleosides increased by 9- to 282-fold. Besides, the C 12 mimBr-coated adsorbent did not lose selectivity and was able to capture cis-diols in the presence of a 100-fold excess of interferences. C 12 mimBr-coated material was applied to selective enrichment of nucleosides from human urine. The limits of detection and the limits of quantification were in the range of 0.06–0.46 ng mL −1 and 0.20–1.53 ng mL −1 , respectively. Reproducibility of the method was determined with relative standard deviations≤9.9%. The recoveries of the target nucleosides from spiked human urine were in the range of 87.8–109.6%. In our preception, self-assembly ionic liquid layer can serve as a promising alternative to improve the extraction efficiency of boronate affinity materials.
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JOURNAL OF CHROMATOGRAPHY A
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2017
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IF 3.981
Chusheng Liu,Haibin Li,Qiqin Wang,Jacques Crommen,Haibo Zhou,Zhengjin Jiang
The quest for higher column efficiency is one of the major research areas in polymer-based monolithic column fabrication. In this research, two novel polymer-based HILIC monolithic columns with 400 μm I.D. × 800 μm O.D. were prepared based on the thermally initiated co-polymerization of N,N -dimethyl- N -(3-methacrylamidopropyl)- N -(3-sulfopropyl) ammonium betaine (SPP) and ethylene glycol dimethacrylate (EDMA) or N,N’ -methylenebisacrylamide (MBA). In order to obtain a satisfactory performance in terms of column permeability, mechanical stability, efficiency and selectivity, the polymerization parameters were systematically optimized. Column efficiencies as high as 142, 000 plates/m and 120, 000 plates/m were observed for the analysis of neutral compounds at 0.6 mm/s on the poly(SPP- co -MBA) and poly(SPP- co -EDMA) monoliths, respectively. Furthermore, the Van Deemter plots for thiourea on the two monoliths were compared with that on a commercial silica based ZIC-HILIC column (3.5 μm, 200 Å, 150 mm × 300 μm I.D.) using ACN/H 2 O (90/10, v/v) as the mobile phase at room temperature. It was noticeable that the Van Deemter curves for both monoliths, particularly the poly(SPP- co -MBA) monolith, are significantly flatter than that obtained for the ZIC-HILIC column, which indicates that in spite of their larger internal diameters, they yield better overall efficiency, with less peak dispersion, across a much wider range of usable linear velocities. A clearly better separation performance was also observed for nucleobases, nucleosides, nucleotides and small peptides on the poly(SPP- co -MBA) monolith compared to the ZIC-HILIC column. It is particularly worth mentioning that these 400 μm I.D. polymer-based HILIC monolithic columns exhibit enhanced mechanical strength owing to the thicker capillary wall of the fused-silica capillaries.
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JOURNAL OF CHROMATOGRAPHY A
·
2016
·
IF 3.926
Jialiang Guo,Yuan Xiao,Yuanjing Lin,Jacques Crommen,Zhengjin Jiang
Low column efficiency for enantioseparations in capillary liquid chromatography (CLC) is a major problem commonly encountered with β -cyclodextrin ( β -CD) functionalized polymer-based monoliths. In order to investigate the effect of the crosslinker type on enantioseparation performance, three commonly used crosslinkers, i.e. 1,4-bis(acryloyl)piperazine (PDA), ethylene dimethacrylate (EDMA) and N , N -methylenebisacrylamide (MBA), were copolymerized using the one-pot approach with glycidyl methacrylate-mono-6-amino-6-deoxy- β -CD (GMA-NH 2 - β -CD) as functional monomer. The three monolithic columns, including poly(GMA-NH 2 - β -CD- co -PDA) and poly(GMA-NH 2 - β -CD- co -MBA), as well as the previously reported column poly(GMA-NH 2 - β -CD- co -EDMA) were systematically compared with respect to morphology, permeability, β -CD density, retention mechanism and efficiency. The enantioseparation ability of each column was evaluated using 14 chiral compounds, including mandelic acid derivatives, profens, N -derivatized amino acids, and herbicides, as test substances. The β -CD-functionalized monolith with MBA as crosslinker was found to exhibit higher polarity, higher column efficiency and better enantioseparation performance than those with PDA or EDMA as crosslinker.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2017
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IF 3.671
Jinsong Zhang,Youzhi Zhou,Ke Liu,Jianlin Chu,Yewei Zhang,Bingfang He
A novel nucleoside 2′-deoxyribosyltransferase ( Lh NDT) from Lactobacillus hilgardii ZJS01 was cloned and expressed in Escherichia coli BL21 (DE3). The amino acid sequence of Lh NDT displayed the highest identity of 26% to other reported NDTs. Lh NDT was a monomer as revealed by gel filtration chromatography with or without addition of Ca 2+ in elution buffer. This enzyme showed a high activity and stability over a broad pH range and was sensitive to temperature. With the addition of 15 mM Ca 2+ , the thermostability of Lh NDT was greatly promoted by 63 times and 46 times at 30 °C and 35 °C, respectively. With the use of 2′-deoxyuridine as sugar donor at an economic molar ratio of 1:1, 5-aza-2′-deoxycytidine (46%) and 5-fluoro-2′- deoxycytidine (58%) were efficiently synthesized from 5-azacytosine and 5-fluorocytosine, respectively, by Lh NDT for 2 h.
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BIOMEDICAL CHROMATOGRAPHY
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2016
·Vol. 31
·期 4
·e3860
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IF 1.729
Yan Du,Yin-jie Li,Xun-xiu Hu,Xu Deng,Zeng-ting Qian,Zheng Li,Meng-zhe Guo,Dao-quan Tang
As essential endogenous compounds, nucleobases and nucleosides fulfill various functions in living organisms. This study presents the development and validation of a new hydrophilic interaction liquid chromatography tandem mass spectrometry method for simultaneous quantification of 19 nucleobases and nucleosides in rat plasma. For the sample preparation, 15 kinds of protein precipitants were evaluated according to the chromatographic profile and ion response of analytes. The optimization of chromatographic separation was respectively performed using reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography mode; each separation mode included two test columns with different stationary phases. The chromatographic profile and parameters such as half-width ( W 1/2 ), capacity factor ( K ′) and tailing factor ( f t ) were used to evaluate the separation efficiencies. Furthermore, the adopted composition of two mobile phase systems and the concentrations of the additives in the optimum buffer system were also investigated. The developed method was fully validated and successfully applied quantitatively to determine 19 nucleobases and nucleosides in plasma from normal and diabetic nephropathy (DN) rats. Significant differences between normal and DN rats were found in plasma levels of cytosine, xanthine, thymidine, adenosine, guanosine, inosine and 8-hydroxy-2′-deoxyguanosine. This information may provide a useful reference for the discovery of potential biomarkers of DN.
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Nature Communications
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2017
·Vol. 8
·期 1
·1-15
·
IF 12.124
Wu Liufeng,Meng Jia,Shen Qing,Zhang Yi,Pan Susu,Chen Zhuo,Zhu Ling-Qiang,Lu Youming,Huang Yuan,Zhang Guo
Caffeine, an antagonist of the adenosine receptor A 1 R, is used as a dietary supplement to reduce body weight, although the underlying mechanism is unclear. Here, we report that adenosine level in the cerebrospinal fluid, and hypothalamic expression of A 1 R, are increased in the diet-induced obesity (DIO) mouse. We find that mice with overexpression of A 1 R in the neurons of paraventricular nucleus (PVN) of the hypothalamus are hyperphagic, have glucose intolerance and high body weight. Central or peripheral administration of caffeine reduces the body weight of DIO mice by the suppression of appetite and increasing of energy expenditure. We also show that caffeine excites oxytocin expressing neurons, and blockade of the action of oxytocin significantly attenuates the effect of caffeine on energy balance. These data suggest that caffeine inhibits A 1 Rs expressed on PVN oxytocin neurons to negatively regulate energy balance in DIO mice.
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JOURNAL OF CHROMATOGRAPHY A
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2017
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IF 3.981
Chunmiao Bo,Xiaomeng Wang,Chaozhan Wang,Yinmao Wei
Development of mixed-mode chromatography (MMC) stationary phase with adjustable selectivity is beneficial to meet the needs of complex samples. In this work, surface-initiated atom transfer radical polymerization (SI-ATRP) using the mixture of two functional monomers was proposed as a new preparation strategy for MMC stationary phase with adjustable selectivity. The mixture of sodium 4-styrenesulfonate (NASS) and dimethylaminoethyl methacrylate (DMAEMA) underwent SI-ATRP to bond poly(NASS-co-DMAEMA) on the surface of silica to prepare hydrophilic interaction/ion-exchange mixed-mode stationary phase. Various analytes (neutral, acidic, basic analytes and strong polar nucleosides) were employed to investigate the retention behaviors. The influences of water content and pH of the mobile phase on the retention validated the mixed-mode retention mechanisms of HILIC and ion-exchange. The charge and polarity of stationary phase as well as the separation selectivity were conveniently manipulated by the ratio of NASS to DMAEMA monomer, and the use of DMAEMA in the mixture additionally endowed the column with the temperature-responsive characteristics. Moreover, the application of the developed column was demonstrated by the successful separation of nucleosides, β-agonists and safflower injection. In a word, the proposed strategy can be potentially applied in the controllable preparation of MMC stationary phase with adjustable selectivity.
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TALANTA
·
2017
·
IF 4.162
Shuxia Wang,Huihui Li,Xiujuan Guan,Ting Cheng,Haixia Zhang
Boronic acid modified materials have been widely used to adsorb nucleosides , but their adsorption capacities require further improvement. Most cis -diol containing biomolecules are in very low abundance along with interfering components in real samples, and need to be enriched specially. In this study, we synthesize a kind of silica absorbent modified with boronic acid derivative, using amorphous silica as raw material and obtaining high adsorption capacity for adenosine. In addition, the adsorption equilibrium can be completed within 10 s and 1 min for the desorption. Finally, the material was successfully applied to enrich nucleosides from cells and the spiked recoveries were found between 82.21% and 118.9%. The results showed that the prepared adsorbent has potential to effectively enrich cis-diol substances from cell samples.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2017
·
IF 3.255
Yang Huang,Tingting Zhang,Yumei Zhao,Haibo Zhou,Guangyun Tang,Marianne Fillet,Jacques Crommen,Zhengjin Jiang
Nucleobases, nucleosides and ginsenosides, which have a significant impact on the physiological activity of organisms, are reported to be the active components of ginseng, while they are less present in ginseng extracts. Few analytical methods have been developed so far to simultaneously analyze these three classes of compounds with different polarities present in ginseng extracts. In the present study, a simple and efficient analytical method was successfully developed for the simultaneous separation of 17 nucleobases, nucleosides and ginsenosides in ginseng extracts using supercritical fluid chromatography coupled with single quadrupole mass spectrometry (SFC-MS). The effect of various experimental factors on the separation performance, such as the column type, temperature and backpressure, the type of modifier and additive, and the concentration of make-up solvent were systematically investigated. Under the selected conditions, the developed method was successfully applied to the quality evaluation of 14 batches of ginseng extracts from different origins. The results obtained for the different batches indicate that this method could be employed for the quality assessment of ginseng extracts.
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RSC Advances
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2017
·Vol. 7
·期 74
·46812-46822
·
IF 3.108
Chunmiao Bo,Yinmao Wei
Mixed-mode chromatographic (MMC) stationary phases must be functionalized with at least two functional groups to yield multiple interactions. The present study proposed a novel approach of grafting copolymers with monomers with different properties via surface initiated-atom transfer radical polymerization (SI-ATRP) for the development of MMC stationary phases. In the synthesis, block copolymers and random copolymers containing sodium 4-styrenesulfonate (NASS) and dimethylaminoethyl methacrylate (DMAEMA) units were controllably grafted onto a silica surface via SI-ATRP for the preparation of hydrophilic/ion-exchange stationary phases. Upon investigation of their retention behaviors under different chromatographic conditions (i.e. water content, salt concentration and pH in mobile phase, column temperature) compared to a typical diol column, both the block and random copolymer stationary phases presented mixed-mode retention mechanisms involving hydrophilic and ion-exchange interactions. Furthermore, various solutes, such as basic β-agonists, strong polar nucleosides, organic acids, and a real sample of safflower injection, were employed to evaluate the separation selectivities of the stationary phases; similar selectivities and good separation efficiencies were achieved on the two copolymer columns. In conclusion, the method of surface-grafted copolymers via SI-ATRP possesses potential for further applications in the development of various MMC stationary phases.
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Journal of Analysis and Testing
·
2025
·
IF 7
Li Han,Cui Yuanyuan,Zhen Changqing,Lin Xiaohui,Li Ke,Yang Chengxiong
Microporous organic network (MON) has emerged as efficient stationary phases for high-performance liquid chromatographic (HPLC) separation. Nevertheless, the inherent superhydrophobic networks made their applications limited in the reversed-phase (RP) mode. In this work, a novel amino acid L-cysteine (L-Cys) modified core-shelled microsphere MON@SiO 2 -L-Cys was synthesized via the efficient thiol-yne “click” reaction for hydrophilic interaction chromatography /reversed-phase liquid chromatography (HILIC/RPLC) mixed-mode chromatographic separation. Baseline separation of various hydrophilic and hydrophobic compounds including aromatic ketones, phthalate esters, alkylbenzenes, amines, polycyclic aromatic hydrocarbons, phenols, nucleosides, nucleic acid bases, sulfonamides, water-soluble vitamins, cephalosporin antibiotics, and estrogens was realized on MON@SiO 2 -L-Cys packed column based on the predesigned mixed-mode retention mechanisms. The MON@SiO 2 -L-Cys packed column also exhibited higher selectivity compared to bare SiO 2 , MON@SiO 2 without L-Cys, and C 18 packed columns, revealing the synergistic interactions of MON’s networks and the modified L-Cys molecules. This work provided a feasible way to construct a novel amphipathic MON-based stationary phase, broadened the application scope of MON for hydrophilic analytes, and uncovered the prospects of MON in mixed-mode HPLC.
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