APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2015
·Vol. 81
·期 6
·
IF 3.668
Zhoukun Li,Jiale Wu,Biying Zhang,Fei Wang,Xianfeng Ye,Yan Huang,Qiang Huang,Zhongli Cui
A novel α-amylase, AmyM, was purified from the culture supernatant of Corallococcus sp. strain EGB. AmyM is a maltohexaose-forming exoamylase with an apparent molecular mass of 43 kDa. Based on the results of matrix-assisted laser desorption ionization–time of flight mass spectrometry and peptide mass fingerprinting of AmyM and by comparison to the genome sequence of Corallococcus coralloides DSM 2259, the AmyM gene was identified and cloned into Escherichia coli. amyM encodes a secretory amylase with a predicted signal peptide of 23 amino acid residues, which showed no significant identity with known and functionally verified amylases. amyM was expressed in E. coli BL21(DE3) cells with a hexahistidine tag. The signal peptide efficiently induced the secretion of mature AmyM in E. coli. Recombinant AmyM (rAmyM) was purified by Ni-nitrilotriacetic acid (NTA) affinity chromatography, with a specific activity of up to 14,000 U/mg. rAmyM was optimally active at 50°C in Tris-HCl buffer (50 mM; pH 7.0) and stable at temperatures of <50°C. rAmyM was stable over a wide range of pH values (from pH 5.0 to 10.0) and highly tolerant to high concentrations of salts, detergents, and various organic solvents. Its activity toward starch was independent of calcium ions. The Km and V max of recombinant AmyM for soluble starch were 6.61 mg ml−1 and 44,301.5 μmol min−1 mg−1, respectively. End product analysis showed that maltohexaose accounted for 59.4% of the maltooligosaccharides produced. These characteristics indicate that AmyM has great potential in industrial applications.
研究领域:
生物化学
·
酶学
·
微生物学
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DOI
PubMed
高影响因子
GLYCOCONJUGATE JOURNAL
·
2015
·Vol. 32
·期 8
·643-653
·
IF 2.52
Liang Qun Tao,Du Jia Yan,Fu Qing,Lin Jiang Hui,Wei Zheng
The rare N-unsubstituted glucosamine (GlcNH 3
+ ) residues in heparan sulfate (HS) have important biological and pathophysiological roles. Therefore, the ability to chemically generate a series of oligosaccharides, which have a similar structure to the naturally-occurring, GlcNH 3
+ - containing oligosaccharides from HS, would greatly contribute to investigating their natural role in HS. In this study, a hexasaccharide library that possess GlcNH 3
+ residues were prepared from the chemical modification of the fully sulfated dp6. Chemical reaction conditions were optimized to generate different pattern of GlcNH 3
+ - containing oligosaccharides, then the structure of the library was detected by high-performance liquid chromatography-ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF) analysis. EIC/MS and MS 2 analysis showed different fragmentation patterns of dp6s with different GlcNH 3
+ residues. This provides a foundation for further identification and quantification of GlcNH 3
+ - oligosaccharides by mass spectrum analysis.
研究领域:
生物化学
·
分子生物学
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DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2024
·
IF 10.7
Lingli Zhong,Peiwen Wang,Min Jiang,Yitong Zheng,Xiaofan Xu,Xianfeng Ye,Yan Huang,Yanling Ji,Zhongli Cui,Zhoukun Li
As attractive functional ingredients, maltooligosaccharides (MOS) are typically prepared by controlled enzymatic hydrolysis of starch. However, the random attack mode of amylase often leads to discrete product distribution, thereby reducing yields and purities. In this study, a novel glycoside hydrolase family 13 amylase AmyEs from marine myxobacteria Enhygromyxa salina was identified efficient maltohexaose (G6)-forming ability (40 %, w/w). By deciphering external chain length, we found that the high density of α-1,6-branching points benefits the G6 formation of AmyEs with high purity (71–82 %), indicating the substrate selectivity of AmyEs toward high-branched starch. Based on this, asynchronous conversion strategy was designed to enhance specific MOS yield from corn starch by exploiting branching enzymes and AmyEs, and the purity and yield of G6 respectively increased by 9.5 % and 5 % compared to single AmyEs treatment. Our results demonstrate that combinatorial catalysis of MOS-forming amylases and branching enzymes provides a favorable industrial preparation of specific MOS.
研究领域:
生物化学
·
酶学
·
食品科学
·
微生物学
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DOI
PubMed
高影响因子
ACS Nano
·
2019
·
IF 13.903
Xin Pang,Qicai Xiao,Yi Cheng,En Ren,Lanlan Lian,Yang Zhang,Haiyan Gao,Xiaoyong Wang,Wingnang Leung,Xiaoyuan Chen,Gang Liu,Chuanshan Xu
Rapid emergence of multidrug resistant (MDR) “superbugs” poses a severe threat to global health. Notably, undeveloped diagnosis and concomitant treatment failure remain highly challenging. Herein, we report a sonotheranostic strategy to achieve bacteria-specific labeling and visualized sonodynamic therapy (SDT). Using maltohexaose-decorated cholesterol and bacteria-responsive lipid compositions, a smart nanoliposomes platform (MLP18) was developed for precise delivery of purpurin 18, a potent sonosensitizer proved in this study. Taking advantage of the bacteria-specific maltodextrin transport pathway, the prepared MLP18 can specifically target the bacterial infection site and accurately distinguish the foci from sterile inflammation or cancer with a highly selective fluorescence/photoacoustic signal on the bacteria-infected site of mice. Moreover, the bacteria-responsive feature of MLP18 activated an efficient release and internalization of high concentration sonosensitizer into bacterial cells, resulting in effective sonodynamic elimination of MDR bacteria. In situ MRI monitoring visualized such potent sonodynamic activity and indicated that MLP18-mediated SDT could successfully eradicate inflammation and abscess from mice with bacterial myositis. In view of the above advantages, the developed nanoliposomes may serve as a promising sonotheranostic platform against MDR bacteria in the areas of healthcare.
研究领域:
纳米医学
·
诊疗学
·
传染病学
·
药学科学
·
生物医学工程
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DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Qi Shi,Jingyu Yan,Bin Jiang,Xiujuan Chi,Jihui Wang,Xinmiao Liang,Xuanjun Ai
Two-dimensional NMR spectroscopies are one of the most frequently used techniques for the structural determination of carbohydrates . However, the data analysis is challenging because of the signal overlap in the 1 H homonuclear correlation spectra. We attempted to explore a general strategy for the structural determination of carbohydrates by combined multi-dimensional spectroscopies . The strategy was applied to a human milk oligosaccharide lacto-N-difucohexaose I, that has been previously studied by conventional two-dimensional NMR spectroscopy. Assignment of the intra-residue resonances of the hexasaccharide using the three-dimensional spectrum was straightforward. Consequently, data analysis of the multi-dimensional spectra was significantly simplified, leading to a quicker determination of the intra- and inter-residue connections in the hexasaccharide. Application of the NMR strategy to chondroitin sulfate from bovine cartilage revealed two repeating disaccharide regions of the A and C units of chondroitin sulfate, indicating the high potential of this technique for the structural determination of complex polysaccharides .
研究领域:
化学
·
生物化学
·
光谱学
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DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2021
·
IF 4.952
Lei Zhang,Lingli Zhong,Juying Wang,Yuqiang Zhao,Yiwei Zhang,Yitong Zheng,Weiliang Dong,Xianfeng Ye,Yan Huang,Zhoukun Li,Zhongli Cui
The process of raw starch conversion has attracted extensive attention in recent years due to its high energy conversion efficiency and saving of operational costs. In this study, extensive hydrolysis of raw starch by α-amylase AmyM from Corallococcus sp. EGB was investigated with robust substrate and products tolerance. AmyM showed broad substrate specificity toward raw starches with different types, and kept active and stable over a wide range of temperatures (30–70 °C) and pH values (5.0–9.0) and recycling. The V max values of AmyM towards wheat and corn raw starch were 1111 and 741 μmol/min/mg without depending on Ca 2+ , respectively. SEM analysis showed that AmyM hydrolysis results in the formation of porous and creviced surfaces around the starch granules peripheries. The cost-effective conversion of raw starch for the production of malto-oligosaccharides (MOSs) was identified. AmyM achieved high hydrolysis degree of 90% for 30% wheat and corn raw starch after 20 h at 45 °C with 5 U per mg of raw starch, resulting in formation of 70% MOSs and 30% dextrin. During this process, maltose (G2), maltotriose (G3) and maltotetraose (G4) were produced synchronously with G9 and G11, indicating the potential application in enzymatic conversion of raw starch under low temperature.
研究领域:
生物化学
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酶学
·
食品科学
·
生物技术
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DOI
高影响因子
BIOMATERIALS
·
2024
·
IF 12.8
Jian He,Xiuhui Lin,Dongxiao Zhang,Huiqun Hu,Xiaoyuan Chen,Feng Xu,Min Zhou
The hypometabolic and nutrient-limiting condition of dormant bacteria inside biofilms reduces their susceptibility to antibacterial agents, making the treatment of biofilm-dominating chronic infections difficult. Herein, we demonstrate an intratracheal aerosolized maltohexaose-modified catalase-gallium integrated nanosystem that can ‘wake up’ dormant Pseudomonas aeruginosa biofilm to increase the metabolism and nutritional iron demand by reconciling the oxygen gradient. The activated bacteria then enhance suicidal gallium uptake since gallium acts as a 'Trojan horse' to mimic iron. The internalized gallium ions disrupt biofilms by interfering with the physiological processes of iron ion acquisition and utilization, biofilm formation, and quorum sensing. Furthermore, aerosol microsprayer administration and bacteria-specific maltohexaose modification enable accumulation at biofilm-infected lung and targeted release of gallium into bacteria to improve the therapeutic effect. This work provides a potential strategy for treating infection by reversing the dormant biofilm's resistance condition.
研究领域:
微生物学
·
药学
·
纳米技术
·
传染病学
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PubMed
高影响因子
APPLIED BIOCHEMISTRY AND MICROBIOLOGY
·
2023
·Vol. 58
·期 1
·S138
·
IF 0.8
Zhang Q.,Li J.,Sun Y.,Song S.,Li X.,Chen G.
Abstract Alzheimer’s disease (AD) is an age-related neurodegenerative disorder. Neuritic plaques containing amyloid-β protein (Aβ) and neurofibrillary tangles composed of hyperphosphorylated tau protein constitute major neuropathological hallmarks of AD. The neurotoxicity of aggregated Aβ has been implicated as a critical cause in the pathogenesis of AD. The aim of this study was to exam the use of neoagarohexaose (NAH) in the potential treatment of AD effects, using SH-SY5Y neuronal cell line exposed to β-amyloid protein (Aβ 1-42 ). The present study was designed to explore the neuroprotective effects of NAH on neuroblastoma SH-SY5Y cells as a function of dosage. The cells were exposed to Aβ 1-42 with or without NAH (26.7, 53.4, and 106.8 μM) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used for detecting the viability of treated cells. In treated cells, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were determined using their manufacturer kits. Flow cytometry analysis was used to assess apoptosis, changes in intracellular calcium concentration, and the mitochondrial membrane potential (MMP) after treatment. Additionally, changes in the mechanism of Aβ 1-42 aggregation in the presence of NAH were explored using thioflavin T (ThT) and Congo red (CR) assays. The results showed that incubation with NAH prior to Aβ 1-42 exposure increased cell survival and prevented reactive oxygen species generation. Moreover, NAH decreased the apoptotic rate, inhibited MMP depolarization, reversed the change in intracellular calcium concentration, enhanced the activities of SOD and GSH-Px, and decreased the level of MDA. In addition, the results showed that NAH, which reduced the absorption of the amyloid indicator ThT and CR dyes, was a potent inhibitor of Aβ fibrillogenesis. In conclusion, NAH protects SH-SH5Y cells from Aβ-induced damage by reducing oxidative stress and weakens the spontaneous amyloid formation of Aβ fibrils in vitro and can inhibit the amyloidization of amyloid β protein (Aβ). This study shows that NAH may be a promising anti-AD drug candidate for AD treatment.
研究领域:
神经科学
·
药理学
·
细胞生物学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Shuangyu Shao,Xiali Si,Yingtao Zhang,Jun Li,Pengfei Tu,Qingying Zhang
Quality analysis of edible mushrooms based on polysaccharides is generally difficult due to their complicated structures and hard separation. Here, multiple fingerprint analysis of polysaccharides based on chromatographic and spectrometric techniques were developed, and then applied in comparative analysis of Auricularia heimuer (AH), Auricularia cornea (AC), Auricularia cornea ʻYu Muerʼ (ACY) and Tremella fuciformis (TF). Firstly, polysaccharides were obtained with the molecular weights between 1.783 × 10 6 and 6.774 × 10 6 Da. Then, complete hydrolysis by TFA and enzyme digestion by cellulase were employed and subsequently analyzed by HPLC-UV, GC–MS, HILIC-HPLC-ELSD and HILIC-HPLC-ESI − -HCD-MS/MS, and ATR-FT-IR were used to characterize the functional groups of intact polysaccharides. By chemometric analysis, differential markers of d -xyl, l -fuc, l -arb, d -glc, disaccharide and hexasaccharide were selected, and AC and ACY were proved to be same species from the viewpoint of polysaccharides firstly. Furthermore, the structures of oligomers with DPs of 2–8 and →4)- β - d -Glc p -(1→ unit with different contents were inferred by combinatory analysis of ESI − -MS/MS, glycosidic linkage, monosaccharide compositions and functional groups. In conclusion, the combinatory method of multiple fingerprint and pattern recognition is powerful not only for structural elucidation of polysaccharides, but also for quality analysis and species differentiation of edible mushrooms from the perspective of biological polysaccharides.
研究领域:
食品科学
·
分析化学
·
真菌学
·
生物化学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）