INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Jian Li,Debao Niu,Ying Zhang,Xin-An Zeng
The influences of different extraction methods on the yields, physicochemical properties, antioxidant activities and antiproliferative abilities of polysaccharides from Morinda citrifolia L. (Noni) were investigated and compared. Three extraction methods were applied to extract Noni polysaccharides (NP), which include hot water extraction (HWE), pulsed electric field-assisted extraction (PEFAE) and ultrasonic-assisted extraction (UAE). The extraction yields, sugar contents, uronic acid contents, molecular weights, monosaccharide proportions, antioxidant activities and antiproliferative abilities of three NP samples were significantly different. However, their preliminary structural characteristics and monosaccharide types were similar. More specifically, UAE-NP had the highest extraction yield, the smallest molecular weight and the best antioxidant activities. Especially, UAE-NP showed excellent antiproliferative abilities. Compared with HWE-NP and PEFAE-NP, the IC 50 value of UAE-NP on HepG2 cells reduced by 45.45% and 33.14%, respectively. The highest antioxidant activities of the UAE-NP might be attributed to its smaller molecular weight, lower Gal content and higher Fuc content. The strongest antiproliferative effects of the UAE-NP might be related to the low molecular weight. Overall, UAE could be a potential technique for the extraction of high-quality NP due to its high yield, high efficiency and notable bioactivities.
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高影响因子
CURRENT MICROBIOLOGY
·
2020
·Vol. 77
·期 6
·1016-1023
·
IF 1.746
Yue Xue,Yan Bingyu,Wang Shuai,Gao Wen,Zhang Ruiyan,Dong Huijun
The glycopeptide A40926 biosynthesized by Nonomuraea gerenzanensis is a precursor of the second generation glycopeptide antibiotic dalbavancin. The skeleton of this glycopeptide consists of seven amino acids and is biosynthesized by the NRPS gene module. L-valine, a branched amino acid, is also a significant precursor for A40926 production. This study details the use of pH-responsive alginate–chitosan microspheres loaded with L-valine prepared by internal emulsification gelation. The effects of process and formulation variables on microsphere size, loading capacity, and encapsulation efficiency were investigated. Then, effects on A40926 production by the pH-responsive microspheres were evaluated in a 10-L fermenter. Results demonstrated that use of the pH-responsive microspheres could improve A40926 yield from 465 to 602 mg L −1 in a 10-L scale fermenter.
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Frontiers in Chemistry
·
2020
·
IF 3.693
Chen Pin,Kong Jingyang,Wang Xin,Ma Weiye,Yang Xia,Qin Yuqing,Hu Xiaohong
Synthesized polypeptide is attracting an increased interests due to its excellent biological characteristic and adjustable chemical properties in bio-related fields. But polypeptide itself has no switching properties, which is harmful to the development of its application as a control component. Herein, light-responsive poly(γ-benzyl-L-glutamate)s (PBLGs) is synthesized by a one-step NCA method using p-aminoazobenzene (m-AZO) and p-diaminoazobenzene (m-DAZO) as initiators. PBLGs exhibit amorphous characteristics with obvious Tg transition, which are 14°C for PBLG1 and 21°C for PBLG2. In order to forecast the structure-property information of PBLGs, theoretical UV-vis spectra as well as the energy gap between HOMO and LUMO is calculated by DFT calculation. Experimental results of UV-vis spectra exhibit similar characteristics to those of theorical UV-vis spectra except for the 40–50 nm red-shifting of absorbance peak. Furthermore, the absorbance intensities of PBLGs have a good linear relationship with their concentration, but their linearity range depending on concentration is completely different. Then, trans–cis transition under a different excitation source and cis–trans recovery in a dark environment are tracked in real-time by UV-vis spectra to evaluate the light response performances. It is found that UV light is the only effective excitation source for PBLG1, and blue light is another effective excitation source for PBLG2 besides UV light. Furthermore, the addition of alcohol and water as cosolvents has little effect on trans→cis transition in UV-light-excited systems, but it shortens recovery time of the cis→trans process in a dark environment. By contrast, the detectable isomerization process becomes unclear with the addition of alcohol in blue-light-excited system. Furthermore, either alcohol or water in solvents accelerate both the trans→cis and cis→trans process in a blue-light-excited system.
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JOURNAL OF ANALYTICAL CHEMISTRY
·
2020
·Vol. 75
·期 1
·111-118
·
IF 0.84
Congming Li,Zhou Yanli,Ye Baoxian,Xu Maotian
Abstract A novel, economic, and highly sensitive electrochemical sensor for the determination of trans -resveratrol ( RES ) was fabricated by electropolymerization of poly(L-lysine) films onto glassy carbon electrode ( GCE ) surface. The electrochemical behavior of RES in Britton–Robinson buffer solution (pH 2.0) on the poly(L-lysine)/GCE was investigated by cyclic voltammetry and linear sweep voltammetry for the first time. Results showed that the detection range of the proposed sensor to RES was from 0.20 to 12.0 μM with the minimum detectable concentration of 0.06 μM. The reported electrochemical sensor also exhibited high selectivity, good reproducibility, and long-term stability for RES detection. In addition, the proposed method can be employed for the determination of RES in red wines with satisfactory results. The proposed electrochemical strategy presents valuable information related to evaluation of RES levels in real samples.
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POLYMER BULLETIN
·
2020
·Vol. 78
·期 1
·147-163
·
IF 2.014
Shao Jun,Xu Lanli,Pu Shouzhi,Hou Haoqing
Blending of poly( l -lactide) and poly( d -lactide) (PLLA, PDLA) results in the formation of poly(lactide) stereocomplex crystallites (SC). For the preparation method, numerous reports employed solution mixing and stirring to receive a product with uniform performance. However, the effect of stirring time during solution mixing on the subsequent crystallization behavior did not clear yet, and which is important for solution crystallization, casting and spinning. In this paper, linear PLLA and PDLA with various molecular weights were synthesized. The PLLA and PDLA solutions were mixed together and stirred for different times before casting. Results revealed that the structures of PLA SC and homochiral crystallites (HC) did not vary with change in the stirring time. More amount of content of SC with uniform structure and less amount of content of HC were produced in the specimens stirred for longer time. When the specimens crystallized either from the melt or from the melt-quenching, less amount of content of crystallites (total crystallinity of SC and HC) was produced and the melting temperature of SC and HC depressed in the specimens that were stirred for longer time. With the increase in molecular weights, the effect of stirring time on the crystallization behaviors declined. This investigation provides a route to tailor the crystallization behavior of PLLA/PDLA specimens.
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FOOD CHEMISTRY
·
2020
·
IF 6.306
Shuo Shi,Wentao Zhang,Xinnan Liu,Xinyi Ren,Min Li,Jing Sun,Yutang Wang,Tianli Yue,Jianlong Wang
Lycium barbarum L. polysaccharides (LBPs) with outstanding biological activities are of increasing interest. Traditional purification approaches are time-consuming and often involve toxic solvents that destroy the functionality and structure of polysaccharides. Herein, we report a sustainable and nondestructive strategy for purifying LBPs using graphene-based nano-decoloration. The amination of graphene oxide (GO) enables the resulted aminated reduced GO (NH 2 -rGO) with abundant sp 2 -hybridized carbon domains, displaying high adsorption capacity toward pigments in crude polysaccharides. As such, within 5 min, NH 2 -rGO can highly effectively and fast to decolor LBPs, with a high decoloration ratio of 98.72% and a high polysaccharides retention ratio of 95.62%. Importantly, compared with traditional decoloration methods, NH 2 -rGO is nondestructive toward LBPs and has good reusability. Moreover, it exhibited widespread-use decoloration performance to decolor several common plant species. Overall, our proposed nano-decoloration approach is a general-purpose, sustainable, and nondestructive method to purify LBPs.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 39
·期 1
·122-132
·
IF 3.154
Yu Man-Man,Yang Wei-Jun,Niu De-Yu,Cai Xiao-Xia,Weng Yun-Xuan,Dong Wei-Fu,Chen Ming-Qing,Xu Peng-Wu,Wang Yang,Chu Hong,Ma Pi-Ming
In this work, hydroxyl-terminated oxalamide compounds N 1 , N 2 -bis(2-hydroxyethyl)oxalamide (OXA1) and N 1 , N 1′ -(ethane-1,2-diyl)bis( N 2 -(2-hydroxyethyl)oxalamide (OXA2) were synthesized to initiate the ring-opening polymerization of L-lactide for preparation of oxalamide-hybridized poly(L-lactide) (PLA OXA ), i.e. , PLA OXA1 and PLA OXA2 . The crystallization properties of PLA were improved by the self-assembly of the oxalamide segments in PLA OXA which served as the initial heterogeneous nuclei. The crystal growth kinetics was studied by Hoffman-Lauritzen theory and it revealed that the nucleation energy barrier of PLA OXA1 and PLA OXA2 was lower than that of PLA. Consequently, PLA OXA could crystallize much faster than PLA, accompanied with a decrease in spherulite size and half-life crystallization time by 74.8% and 86.5% (T = 125 °C), respectively. In addition, the final crystallinity of PLA OXA1 and PLA OXA2 was 6 and 8 times higher, respectively, in comparison with that of neat PLA under a controlled cooling rate of 10 °C/min. The results demonstrate that the hybridization of oxalamide segments in PLA backbone will serve as the self-heteronucleation for promoting the crystallization rate. The higher the content of oxalamide segments (PLA OXA2 compared with PLA OXA1 ) is, the stronger the promotion effect will be. Therefore, this study may provide a universal approach by hybridizing macromolecular structure to facilitate the crystallization of semi-crystalline polymer materials.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Zhencheng Yu,Chuanshuang Hu,Litao Guan,Weiwei Zhang,Jin Gu
In this study, we reported an environmentally benign method for the synthesis of silver nanoparticles (AgNPs) by using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (CNFs) as the only reducing agent and stabilizer under mild aqueous conditions. The AgNPs were tightly adhered to the CNF surface, and the resulting stable CNF–AgNP suspension can be used for rapid and selective detection of l-cysteine (Cys). The efficacy of the process relies upon the surface plasmon resonance properties of AgNPs and the aggregation effect of AgNPs in the presence of Cys. Under optimal ionic strength provided by NaCl, Cys interacted with AgNPs, leading to a change in yellow color of the CNF–AgNP to purple. The colloidal suspension showed high sensitivity (limit of detection of 49 nM) and rapid (5 min) and selective detection of Cys among 20 amino acids that make up human proteins, hence demonstrating great potential for analyzing practical samples.
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RSC Advances
·
2019
·Vol. 9
·期 57
·32977-32983
·
IF 3.049
Yuang Mao,Chang Zhao,Shuyan Ge,Tao Luo,Jie Chen,Jiyang Liu,Fengna Xi,Junjie Liu
Sensitive and reliable detection of mercury ions (Hg2+) and L-cysteine (L-Cys) is of great significance for toxicology assessment, environmental protection, food analysis and human health. Herein, we present gram-scale synthesis of nitrogen doped graphene quantum dots (N-GQDs) for sensitive detection of Hg2+ and L-Cys. The N-GQDs are one-step synthesized using bottom-up molecular fusion in a hydrothermal process with gram-scale yield at a single run. N-GQDs exhibit good structural characteristics including uniform size (∼2.1 nm), high crystallinity, and single-layered graphene thickness. Successful doping of N atom enables bright blue fluorescence (absolute photoluminescence quantum yield of 24.8%) and provides unique selectivity towards Hg2+. Based on the fluorescence quenching by Hg2+ (turn-off mode), N-GQDs are able to serve as an effective fluorescent probe for sensitive detection of Hg2+ with low limit of detection (19 nM). As L-Cys could recover the fluorescence of N-GQDs quenched by Hg2+, fluorescent detection of L-Cys is also demonstrated using turn-off-on mode.
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Asia-Pacific Journal of Chemical Engineering
·
2022
·Vol. 18
·期 2
·e2871
·
IF 1.777
Biao Jin,Shanshan Liu,Dongri Jin
The design of electrode materials for sensitive electrochemical sensors is important for the rapid detection of ascorbic acid. Using Physalis alkekengi L. husks (PaLH) as the carbon precursor, PaLH-derived carbon materials (PCM) were prepared by high temperature carbonization, and hierarchical porous carbon materials (KPCM) were prepared by KOH activation. The carbon materials were characterized by scanning electron microscopy, X-ray diffraction, and isothermal nitrogen adsorption and desorption. KPCM had a larger specific surface area (1345.45 m 2 g −1 ) and more micro/mesopores than PCM without KOH activation. Two types of carbon materials, PCM and KPCM, were used as electrode modifiers, and the electrochemical properties of KPCM/GCE and PCM/GCE (GCE = glassy carbon electrode) were investigated. KPCM/GCE had a higher electron-transfer rate, higher electrochemically active area, smaller charge-transfer resistance, wider potential window, and higher catalytic activity for ascorbic acid detection. An ascorbic acid electrochemical sensing platform constructed with KPCM/GCE showed high sensitivity (334.03 μA mM −1 cm −2 and 134.52 μA mM −1 cm −2 ) and a low detection limit (0.92 μM) ( S/N = 3) in the linear range of 0.005–1.6 mM. This method was applied to the analysis and determination of ascorbic acid in chewable vitamin C tablets.
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Nutrients
·
2022
·Vol. 14
·期 21
·4549
·
IF 6.706
Tongtong Ba,Dai Zhao,Yiqin Chen,Cuiping Zeng,Cheng Zhang,Sai Niu,Hanchuan Dai
L-citrulline (L-cit) is a key intermediate in the urea cycle and is known to possess antioxidant and anti-inflammation characteristics. However, the role of L-cit in ameliorating oxidative damage and immune dysfunction against iron overload in the thymus remains unclear. This study explored the underlying mechanism of the antioxidant and anti-inflammation qualities of L-cit on iron overload induced in the thymus. We reported that L-cit administration could robustly alleviate thymus histological damage and reduce iron deposition, as evidenced by the elevation of the CD8+T lymphocyte number and antioxidative capacity. Moreover, the NF-κB pathway, NCOA4-mediated ferritinophagy, and ferroptosis were attenuated. We further demonstrated that L-cit supplementation significantly elevated the mTEC1 cells’ viability and reversed LDH activity, iron levels, and lipid peroxidation caused by FAC. Importantly, NCOA4 knockdown could reduce the intracellular cytoplasmic ROS, which probably relied on the Nfr2 activation. The results subsequently indicated that NCOA4-mediated ferritinophagy was required for ferroptosis by showing that NCOA4 knockdown reduced ferroptosis and lipid ROS, accompanied with mitochondrial membrane potential elevation. Intriguingly, L-cit treatment significantly inhibited the NF-κB pathway, which might depend on restraining ferritinophagy-mediated ferroptosis. Overall, this study indicated that L-cit might target ferritinophagy-mediated ferroptosis to exert antioxidant and anti-inflammation capacities, which could be a therapeutic strategy against iron overload-induced thymus oxidative damage and immune dysfunction.Keywords:L-citrulline;thymus;iron overload;ferritinophagy;ferroptosis
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MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Jiadong Chen,Hongyi Li,Dong Shao,Tao Long,Lanying Xu,Junlun Zhu
Due to their outstanding advantages, photoelectrochemical (PEC) sensors have gained significant attention, which can realize the rapid and accurate detection of target. However, the semiconductor as its core component has a strong influence on the analysis and detection performance. Herein, we developed a simple and efficient method to prepare heterojunction for the construction of PEC sensor detecting L-cysteine (L-Cys). The rod-like copper-based metal organic framework was prepared by room temperature synthesis method, which was used to derive rod-like CuO/Cu 2 O/C heterojunction with excellent photoelectric property. Due to L-Cys interacts with CuO/Cu 2 O/C heterojunction to form steric hindrance effect through Cu-S bond, which reduces the photocurrent signal and realizes the selective and homogeneous detection of L-Cys. Inspired by this steric strategy, a PEC sensing platform was fabricated by CuO/Cu 2 O/C heterojunction for the homogeneous detection of L-Cys, showing linear responses in the range of 0.2 μM to 50 μM with the detection limit of 0.12 μM. Our work shed light on the advancement of better PEC sensor and the method of constructing heterojunction.
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