BIOPOLYMERS
·
2013
·Vol. 101
·期 3
·210-215
·
IF 2.879
Xin Liu,Tong Chen,Yan Hu,Kexin Li,Liushui Yan
Sulfated derivatives of polysaccharide from Momordica charantia L. (MCPS) with different degree of sulfation (DS) were synthesized by chlorosulfonic acid method with ionic liquids as solvent. Fourier transform infrared spectra and 13 C nuclear magnetic resonance spectra indicated that C-6 substitution was predominant in MCPS compared with the C-2 position. Compared with the native polysaccharide from Momordica charantia L. (MCP), MCPS exhibited more excellent antioxidant activities in vitro, which indicated that sulfated modification could enhance antioxidant activities of MCP. Furthermore, high DS and moderate molecular weight could improve the antioxidant activities of polysaccharide. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 210–215, 2014.
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PLoS One
·
2014
·Vol. 9
·期 6
·e100731
·
IF 3.534
Ke Xu,Ping Xu
Lactic acid is an important chemical with various industrial applications, and it can be efficiently produced by fermentation, in which Bacillus coagulans strains present excellent performance. Betaine can promote lactic acid fermentation as an effective osmoprotectant. Here, positive effect of betaine on fermentation by B. coagulans is revealed. Betaine could enhance lactic acid production by protecting l -LDH activity and cell growth from osmotic inhibition, especially under high glucose concentrations and with poor organic nitrogen nutrients. The fermentation with 0.05 g/L betaine could produce 17.9% more lactic acid compared to the fermentation without betaine. Beet molasses, which is rich in sucrose and betaine, was utilized in a co-feeding fermentation and raised the productivity by 22%. The efficient lactic acid fermentation by B. coagulans is thus developed by using betaine and beet molasses.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 240
·期 4
·743-751
·
IF 1.387
Zhou Cunliu,Ye Huiqiong,Wang Hui,Qin Hao,Li Junhong
This work evaluated the effects of l -arginine on the stability of porcine hemoglobin concentrates during storage. The addition of l -arginine increased both the oxyhemoglobin content and a* values but decreased both the methemoglobin content and free iron content ( p < 0.05) during storage. The addition of iron cation decreased both the oxyhemoglobin content and a* values but increased both the methemoglobin content and free iron content ( p < 0.05). CD spectra disclosed that the free iron induced the transformation of the hemoglobin secondary structure from an α-helix to a β-pleated, β-turn, and random-coil arrangement, while l -arginine hindered the behavior of the free iron. Infrared spectra revealed that the l -arginine coordinated with the free Fe 2+ or Fe 3+ to form the corresponding complex at 25 °C and pH 7.3. These results showed that l -arginine enhanced the stability of hemoglobin concentrates by coordinating with free iron.
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GENE
·
2014
·
IF 2.082
Tao Wu,Anqi Guo,Qingyu Shu,Yangjian Qi,Ying Kong,Zhiping Sun,Shumin Sun,Zhengwei Fu
l -Carnitine supplementation has been used to reduce obesity caused by high-fat diet, which is beneficial for lowering blood and hepatic lipid levels, and for ameliorating fatty liver. However, whether l -carnitine may affect irregular feeding-induced obesity and lipid metabolism disorder is still largely unknown. In the present study, we developed a time-delayed pattern of eating, and investigated the effects of l -carnitine on the irregular eating induced adiposity in mice. After an experimental period of 8 weeks with l -carnitine supplementation, l -carnitine significantly inhibited body weight increase and epididymal fat weight gain induced by the time-delayed feeding. In addition, l -carnitine administration decreased levels of serum alanine aminotransferase (GPT), glutamic oxalacetic transaminase (GOT) and triglyceride (TG), which were significantly elevated by the irregular feeding. Moreover, mice supplemented with l -carnitine did not display glucose intolerance-associated hallmarks, which were found in the irregular feeding-induced obesity. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that l -carnitine counteracted the negative alterations of lipid metabolic gene expression (fatty acid synthase, 3-hydroxy-3-methyl-glutaryl coenzyme A reductase , cholesterol 7α-hydroxylase, carnitine/acylcarnitine translocase) in the liver and fat of mice caused by the irregular feeding. Therefore, our results suggest that the time-delayed pattern of eating can induce adiposity and lipid metabolic disorders , while l -carnitine supplementation might prevent these negative symptoms.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Zhengbo Chen,Jianwei Nai,He Ma,Zhiqiang Li
Hourglass-like nickel hydroxide nanostructure was synthesized via a simple and facile route in solution. The as-prepared nickel hydroxide nanocrystals were characterized by X-ray diffraction (XRD), scanning electronmicroscope (SEM) and transmission electron microscopy (TEM) for the morphology study. The TEM experimental data indicate that the growth of hourglass-like nanocrystal is along the c axis of β-Ni(OH) 2 . The composites had a good electron transferring and biocompatibility. The l -histidine biosensor was fabricated by drop casting the Ni(OH) 2 /ethanol solution (2.5 g L −1 ) on the surface of the glassy carbon electrode (GCE). The prepared biosensor shows better catalytic performance compared with bulk material or other similar materials, with the detection limit of 80 nM and the linear range from 0.1 μM to 0.5 mM ( R 2 = 0.993) in a 0.1 M NaOH solution. The effects of electroactive interferents at the test conditions can be negligible which showed an excellent selectivity of the biosensor. The proposed method was also successfully applied for the determination of l -histidine in human blood serum sample. High sensitivity, excellent selectivity and ease of preparation make this sensor promising for the applications in the development of detecting some other amino acids and proteins.
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ANALYST
·
2014
·Vol. 140
·期 3
·797-802
·
IF 3.906
Chong Sun,Daoying Wang,Muhan Zhang,Yanxiu Ni,Xiaohui Shen,Youchao Song,Zhiming Geng,Weimin Xu,Fang Liu,Chun Mao
The development of advanced nanomaterials for the highly efficient electrical detection of biological species has attracted great attention. Here, novel polypyrrole-Pluronic F127 nanoparticles (PPy-F127 NPs) with conducting and biocompatibility properties were synthesized and used to construct a L-lactic acid biosensor that could be applied in biochemical assays. The PPy-F127 NPs were characterized by transmission electron microscopy (TEM), elemental analysis and UV-vis spectroscopy. Lactate oxidase (LOx) structure variation on the PPy-F127 NPs was investigated by circular dichroism (CD). The cyclic voltammetric results indicated that LOx immobilized on the PPy-F127 NPs exhibited direct electron transfer reaction with a formal potential value (E0′) of 0.154 V vs. SCE. Moreover, the biosensor had good electrocatalytic activity toward L-lactic acid with a wide linear range (0.015–37.5 mM) and a low detection limit of 0.0088 mM. The regression equation was I (μA) = 0.02353c (mM) + 1.4135 (R2 = 0.9939). The L-lactic acid biosensor had a good anti-interference property towards uric acid (UA), ascorbic acid (AA), glucose and cysteine. The idea and method provide a promising platform for the rapid development of biosensors that can be used in the detection of biological species.
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PROCESS BIOCHEMISTRY
·
2024
·
IF 3.7
Puhong Yi,Yue Xu,Hanlin Liu,Yuhua Hao,Mengdan Liu,Zhiqiang Liu,Yaping Xue,Liqun Jin,Yuguo Zheng
2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid (PPO) is a valuable prochiral keto acid for the asymmetric synthesis of the important herbicide L-phosphinothricin (L-PPT). Developing an efficient biocatalytic pathway to meet the increasing demand for PPO is highly attractive. In this study, a robust D-amino acid aminotransferase from Cytobacillus firmus ( Cf DAAT) was screened, which exhibited excellent tolerability to D,L-PPT and showed remarkable specific activity and affinity toward pyruvate (61.9 U/mg, Km = 7.4 mM). A designed co-substrate regeneration system was then introduced to shift the reaction equilibrium forward by coupling with D-amino acid oxidase (DAAO) and catalase (CAT). An efficient whole-cell biocatalyst was obtained by fine-tuning RBS intensity to coordinate the co-expression of the three enzymes. Moreover, the optimum conditions to promote overall conversion efficiency were identified by response surface methodology. Consequently, with only a catalytic amount of pyruvate (3.33 mol%) added in a 1 L reaction system, 200 mM D-PPT (400 mM D,L-PPT) was completely converted in 10 h, resulting in a PPO productivity of 3.33 g⋅L −1 ⋅h −1 , and a notable conversion rate of >99% at 300 mM D-PPT in 16 h. It demonstrated a considerable catalytic level and provided a competitive route for industrial PPO production from D,L-PPT.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Zhenqiang Zhao,Jiajia You,Xuanping Shi,Rongshuai Zhu,Fengyu Yang,Meijuan Xu,Minglong Shao,Rongzhen Zhang,Youxi Zhao,Zhiming Rao
Exploring effective remodeling strategies to further improve the productivity of high-yield strains is the goal of biomanufacturing. However, the lack of insight into host-specific metabolic networks prevents timely identification of useful engineering targets. Here, multidimensional engineering strategies were implemented to optimize the global metabolic network for improving l-threonine production. First, the metabolic bottleneck for l-threonine synthesis was eliminated by synergistic utilization of NADH and an enhanced ATP supply. Carbon fluxes were redistributed into the TCA cycle by rationally regulating the GltA activity. Subsequently, the stress global response regulator UspA was identified to enhance l-threonine production by a transcriptomic analysis. Then, l-threonine productivity was improved by enhancing the host’s stress resistance and releasing the inhibitory reaction of glucose utilization. Eventually, the l-threonine yield of THRH16 reached 170.3 g/L and 3.78 g/L/h in a 5 L bioreactor, which is the highest production index reported. This study provides rational guidance for increasing the productivity of other chemicals.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Shiming Tang,Zhilin Ouyang,Ying Huo,Daocheng Liao,Zhiteng Zhang,Ying Lin,Suiping Zheng
Hydroxytyrosol has been proven beneficial to human health. However, the process involving the conversion of L-DOPA to 3,4-dihydroxyphenylacetaldehyde (3,4-DHPAA) in hydroxytyrosol biosynthesis typically required the simultaneous use of decarboxylase and oxidative deaminase. In addition, phenylacetaldehyde reductase from Solanum lycopersicum (SlPAR) in hydroxytyrosol biosynthesis exhibits poor thermal stability. In this study, we unexpectedly discovered that L-DOPA decarboxylase from Pseudomonas putida (PpDODC) exhibits weak dual-functional activity for both decarboxylation and oxidative deamination of L-DOPA. Through a dual-function reshaping strategy, the best dual-functional mutant PpDODC/Y79F/Y324F achieved an enzyme activity of 0.95 U/mg and exhibited a 256.8-fold increase in activity compared to the wild-type. Through rational design of SlPAR, the optimal mutant SlPAR/G52D/V188I/N234W/Q286P (SlPAR-M4) maintained stability after 12 h' treatment at 40 °C. Based on these mutants, we established a simplified cascade to synthesize hydroxytyrosol from L-DOPA, achieving a hydroxytyrosol yield of 31.4 mM from 32 mM L-DOPA in a 5-hour reaction. This process achieved the highest molar conversion rate (98.2 %) currently reported for the synthesis of hydroxytyrosol from L-DOPA. This study provides a novel solution for hydroxytyrosol synthesis from a new perspective, and the mutants hold promise for widespread application in biotransformation studies of hydroxytyrosol and other structurally-similar compounds.
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Analytical Methods
·
2024
·Vol. 16
·期 24
·3907-3916
·
IF 2.7
Bozhi Lang,Wenming Ma,Xuan Liao,Yaning Duan,Cuiling Ren,Hongli Chen
New chiral carbon dots (CDs), L-PCDs, for discriminating tryptophan (Trp) enantiomers were prepared in this work. Firstly, original CDs were synthesized through a hydrothermal method using pyridine-2,6-dicarboxylic acid and o-phenylenediamine as raw materials. Then, the surface of original CDs was modified with L-phenylalanine to create chiral fluorescent carbon L-PCDs. In the presence of D-Trp, the fluorescence intensity of L-PCDs decreased significantly while it remained unchanged in the presence of L-Trp. The chiral sensing system used in this study has a rapid response time of 3 minutes and can identify enantiomers with an enantioselectivity (ID/IL) of up to 3.3. For D-Trp, a good linear relationship can be obtained in the range of 0.3–4.2 mM with a limit of detection of 0.06 mM. This sensor allows for both quantitative detection of D-Trp and determination of enantiomeric percentage in the racemate. The chiral recognition mechanism is attributed to the different interaction between D-/L-Trp and L-PCDs.
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ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Shenzhen Cong,Si Sun,Yijing Zhang,Ming Wang,Zhehua Jia,Youhua Zhao,Huan Pang
Metal–organic framework (MOF) membranes offer a wide range of applications, including simultaneous hydrogen generation and decarbonization. The permselectivity of gas molecules can be considerably increased by optimizing the oriented of MOF membranes, and it is possible to construct MOF membranes with high permeance and high selectivity. Here, chelation-assisted interfacial growth is used to prepare ZIF-L membranes for H 2 /CO 2 separation. The growth rate of the ZIF-L crystal plane is regulated by optimizing the interface Zn 2+ diffusion, and a ZIF-L membrane with preferred orientation is constructed for efficient separation of H 2 /CO 2 . The optimized ZIF-L membrane has an H 2 permeance of over 2000 GPU, and the H 2 /CO 2 selectivity exceeds 30. Additionally, the prepared ZIF-L membrane exhibits outstanding operating stability and tolerance, making it a promising candidate for industrial applications.
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Cell Metabolism
·
2025
·
IF 30.9
Yu-Zhang Wang,Wei-Hai Chen,Zi-Yi Han,Shi-Man Zhang,Ping Ji,Cheng Zhang,Jun-Long Liang,Xian-Zheng Zhang
Bacteria-based metabolic therapy has been acknowledged as a promising strategy for tumor treatment. However, the insufficient efficiency of wild-type bacteria severely restricts their therapeutic efficacy. Here, we elaborately develop an ʟ-cyst(e)ine-addicted bacteria-nanodrug biohybrid for metabolic therapy through a dual-selection directed evolution strategy. Our evolved strain exhibits a 36-fold increase in ʟ-cystine uptake and a 23-fold improvement in total activity of cysteine desulfhydrases compared with the wild-type strain. By conjugating with DMXAA-loaded liposomes, the engineered bacteria-nanodrug biohybrid not only prevents the influx of nutrients into the tumor by blocking neovasculature but also achieves efficient and durable CySS catabolism locally. The unavailable of Cys species disrupts redox homeostasis and strikingly increases intracellular ROS level, achieving favorable therapeutic outcomes in multiple tumor models. Our study not only highlights the promise of directed evolution strategy in enhancing the stability and efficiency of bacteria-based living biocatalyst but also provides new opportunities for antitumor metabolic therapy.
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