Journal of Macromolecular Science Part B-Physics
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2021
·
IF 1.504
Meiling Yi,Zhihua Zhou,Wenjuan Liu,Tianlong Huang,Yanmin Zhao,Ping Chen,Ziwei Zhou,Dan Wang,Chao Zhang,Jianjun Fang
Among drug delivery systems, polymer microspheres have been proved to be the most promising carriers during the past several years. In this paper we describe the preparation of poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) random terpolymer microspheres; their in-vitro degradation behaviors, including the changes of pH value, mass loss, molecular mass and surface morphology, were investigated during various degradation periods and compared with poly(lactic-co-glycolic acid) (PLGA) microspheres. The results showed that the introduction of the ε-caprolactone (ε-CL) unit reduced the degradation rate of the PLGA polymers. Therefore, we suggest the PLLGC microspheres with controllable degradation rate could supply a wider application future in drug delivery field than pure PLGA microspheres.
研究领域:
生物医学工程
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药剂学
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高分子科学
·
材料科学
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CHINESE JOURNAL OF POLYMER SCIENCE
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2019
·Vol. 38
·期 1
·53-62
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IF 2.804
Chen Tao,Zhong Guo-Cheng,Zhang Yuan-Ting,Zhao Li-Ming,Qiu Yong-Jun
Novel bio-based and biodegradable block copolymers were synthesized by “click” reaction between poly(L-lactide) (PLLA) and polyamide 4 (PA4). Upon tuning the molar mass of PLLA block, the properties of copolymers and electrospun ultrafine fibers were investigated and compared with those of PLLA and PA4 blends. PLLA and PA4 were found incompatible and formed individual crystalline regions, along with reciprocal inhibition in crystallization. Electrospun fibers were highly hydrophobic, even if hydrophilic PA4 was the rich component. The crystallinity of either PLLA or PA4 decreased after electrospinning and PLLA-rich as-spun fibers were almost amorphous. Immersion tests proved that fibers of block copolymers were relatively homogeneous with micro-phase separation between PLLA and PA4. The fibrous structures of copolymers were different from those of the fibers electrospun from blends, for which sheath-core structure induced by macro-phase separation between homopolymers of PLLA and PA4 was confirmed by TEM, EDS, and XPS.
研究领域:
材料科学
·
生物学
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ENZYME AND MICROBIAL TECHNOLOGY
·
2023
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IF 3.4
Lu Zhao,Wenhe Zhang,Qi Wang,Huibin Wang,Xiao Gao,Bin Qin,Xian Jia,Song You
L -Phosphinothricin ( L -PPT) is the effective constituent in racemic PPT (a high-efficiency and broad-spectrum herbicide), and the exploitation of green and sustainable synthesis route for L -PPT has always been the focus in pesticide industry. In recent years, “one-pot, two-step” enzyme-mediated cascade strategy is a mainstream pathway to obtain L -PPT. Herein, Rg DAAO and Bs LeuDH were applied to expand “one-pot, two-step” process. Notably, a NADH-dependent leucine dehydrogenase from Bacillus subtilis ( Bs LeuDH) was firstly characterized and attempted to generate L -PPT, achieving an excellent enantioselectivity (99.9% ee ). Meanwhile, a formate dehydrogenase from Pichia pastoris ( Pp FDH) was utilized to implement NADH cofactor regeneration and only CO 2 was by-product. Sufficient amount of the corresponding keto acid precursor PPO was obtained by oxidation of D -PPT relying on a D -amino acid oxidase from Rhodotorula gracilis ( Rg DAAO) with content conversion (46.1%). L -PPT was ultimately prepared from racemized PPT via oxidative deamination catalyzed by Rg DAAO and reductive amination catalyzed by Bs LeuDH, achieving 80.3% overall yield and > 99.9% ee value.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2023
·Vol. 107
·期 7
·2321-2333
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IF 5
Chi Huibing,Zhu Xiaoyu,Shen Juan,Lu Zhaoxin,Lu Fengxia,Lyu Yunbin,Zhu Ping
Abstract Acrylamide alleviation in food has represented as a critical issue due to its neurotoxic effect on human health. L-Asparaginase (ASNase, EC 3.5.1.1) is considered a potential additive for acrylamide alleviation in food. However, low thermal stability hinders the application of ASNase in thermal food processing. To obtain highly thermal stable ASNase for its industrial application, a consensus-guided approach combined with site-directed saturation mutation (SSM) was firstly reported to engineer the thermostability of Mycobacterium gordonae L-asparaginase (GmASNase). The key residues Gly97, Asn159, and Glu249 were identified for improving thermostability. The combinatorial triple mutant G97T/N159Y/E249Q (TYQ) displayed significantly superior thermostability with half-life values of 61.65 ± 8.69 min at 50 °C and 5.12 ± 1.66 min at 55 °C, whereas the wild-type was completely inactive at these conditions. Moreover, its T m value increased by 8.59 °C from parent wild-type. Interestingly, TYQ still maintained excellent catalytic efficiency and specific activity. Further molecular dynamics and structure analysis revealed that the additional hydrogen bonds, increased hydrophobic interactions, and favorable electrostatic potential were essential for TYQ being in a more rigid state for thermostability enhancement. These results suggested that our strategy was an efficient engineering approach for improving fundamental properties of GmASNase and offering GmASNase as a potential agent for efficient acrylamide mitigation in food industry. Key points
• The thermostability of GmASNase was firstly improved by consensus-guided engineering.
• The half-life and T
m
value of triple mutant TYQ were significantly increased.
• Insight on improved thermostability of TYQ was revealed by MD and structure analysis.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2023
·
IF 2.6
Yankui Xing,Zhengda Zhou,Fangfang Li,Shuangping Tian,Yuxi Liang,Sixian Li,Yanan Zhou,Yun Gao
Thermodynamic properties, which play an important role in design and optimization of crystallization processes, are the essential data for the study of crystal nucleation and growth. In this study, the solubility of L-isoleucine were firstly determined by gravimetric method in three binary solvent mixtures including water + (ethanol, acetonitrile or DMSO) in the temperature range of 303.20 K to 338.05 K at atmospheric pressure. The effects of temperatures and solvent types on the dissolution process of L-isoleucine were investigated. It was found that the solubility of L-isoleucine increased dramatically with the increasing of the mole fraction of water in each binary solvent mixture and increased monotonically with the increasing of temperature. To extend the applicability of the solubility data, the experimental solubility data of L-isoleucine were fitted and analyzed using the modified Apelblat equation, the CNIBS/R-K model and the Jouyban-Acree model. Finally, based on the Van’t Hoff equation and the experimental solubility data, the apparent dissolution thermodynamic properties of L-isoleucine including apparent dissolution enthalpy, apparent dissolution entropy, and apparent Gibbs free energy change of dissolution process were calculated and discussed.
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CRYSTAL GROWTH & DESIGN
·
2023
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IF 3.8
Jiajun Zhong,Hao Wang,Yunpeng Liu,Lixiong Qian,Lei Yao,Xueqing Xing,Guang Mo,Zhongjun Chen,Zhonghua Wu
The leaf-like zeolite imidazolate framework (ZIF-L) with a lamellar structure is an excellent gas adsorption material. It is generally considered that the synthesis of ZIF-L must be carried out in an aqueous solution. In this study, an almost pure ZIF-L crystalline phase with nanoflake morphology was unexpectedly synthesized as the Zn2+ concentration in the methanol solution was greater than or equal to 0.36 M, and the molar ratio of Hmim to Zn2+ was fixed at 4:1. X-ray diffraction was used to characterize the crystalline structure of the product. X-ray absorption fine structure spectra were used to analyze the local atomic structure around Zn. Scanning electron microscopy was used to observe the morphology of products. Through air isolation experiments, it was found that the ambient moisture is a critical factor in determining the final product because the moisture not only penetrated the precursor solution but also participated in the synthesis of the ZIF-L phase. The as-prepared ZIF-L phase exhibits good CO2 adsorption performance. Its CO2 adsorption capacity is 1.09 for ZIF-Zn1, 1.04 for ZIF-Zn2, 1.42 for ZIF-Zn4, and 1.16 mmol/g for ZIF-Zn6 at ambient temperature and normal pressure. This study provides a moisture-assistant approach to synthesize the ZIF-L phase in a non-aqueous solution.
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MOLECULES
·
2023
·Vol. 28
·期 9
·3779
·
IF 4.6
Yaxian Zhao,Xinman Zhao,Mengjia Guo,Krishnapriya M. Varier,Babu Gajendran,Shaohuan Liu,Ling Tao,Xiangchun Shen,Nenling Zhang
Two new stilbenoids, cajanstilbenoid C (1) and cajanstilbenoid D (2), together with eight other known stilbenoids (3-10) and seventeen known flavonoids (11-27), were isolated from the petroleum ether and ethyl acetate portions of the 95% ethanol extract of leaves ofCajanus cajan(L.) Millsp. The planar structures of the new compounds were elucidated by NMR and high-resolution mass spectrometry, and their absolute configurations were determined by comparison of their experimental and calculated electronic circular dichroism (ECD) values. All the compounds were assayed for their inhibitory activities against yeastα-glucosidase. The results demonstrated that compounds3,8-9,11,13,19-21,and24-26had strong inhibitory activities againstα-glucosidase, with compound11(IC50= 0.87 ± 0.05 μM) exhibiting the strongest activity. The structure–activity relationships were preliminarily summarized. Moreover, enzyme kinetics showed that compound8was a noncompetitive inhibitor, compounds11,24-26were anticompetitive, and compounds9and13were mixed-competitive.Keywords:Cajanus cajan;stilbenoid;flavonoid;α-glucosidase inhibitory activity
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2023
·
IF 8.2
Fen Ma,Chenguang Jiang,Wenyuan Xie,Defeng Wu
Using polysaccharide nanocrystals such as chitin nanocrystals (ChNCs) as nanofiller for biodegradable aliphatic polymers is an attractive way of developing all-degradable nanocomposites. Crystallization study is vital for well regulating final performance of these type polymeric nanocomposites. In this work, ChNCs were incorporated with the poly( l -lactide)/poly( d -lactide) blends and as-obtained nanocomposites were used as target samples for the study. The results showed that ChNCs acted as nucleating agent, promoting the formation of stereocomplex (SC) crystallites and accelerating overall crystallization kinetics as a result. Therefore, the nanocomposites possessed higher SC crystallization temperatures and lower apparent activation energy as compared to the blend. However, the formation of homocrystallites (HC) was dominated by nucleation effect of SC crystallites and accordingly, the fraction of SC crystallites reduced more or less in the presence of ChNCs, despite the nanocomposites possessed higher rate of HC crystallization. This study also provided valuable information on accessing more applications of ChNCs to be used as SC nucleator for polylactide.
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CHEMOSPHERE
·
2022
·
IF 8.943
Rui Zhao,Xiufeng Cao,Xinxin Li,Tao Li,Hong Zhang,Xiaowei Cui,Zhaojie Cui
This study aimed to investigate the combined ecotoxicological effects of Cd, Pb, Zn, Hg and regulation mechanisms in Solanum nigrum L. In this work, the co-exposure of these four heavy metals hindered the transformation of Cd, Zn, and Hg (except Pb) from available to non-available chemical forms. Individual Cd, Pb, Zn and Hg induced the oxidative damages to S. nigrum L., while their combination further enhanced this ecological toxicity. By internal regulation, the ecological toxicity of metals to S. nigrum L. could be alleviated to a certain extent. Specifically, S. nigrum L. was a hyperaccumulator of Cd with BCF ＞1. Moreover, since BCFroot of Pb, Zn and Hg were all greater than BCFshoot, S. nigrum L. could accumulate Pb, Hg and Zn mainly in plant roots, which was beneficial for the detoxification of plants. Meanwhile, the immobilization by cell wall (the proportions of Cd, Pb, Zn and Hg in the cell wall were 54.46–84.92%, 38.33–49.25%, 48.38–56.19% and 45.97–63.47% in low metal concentration treatments) and the sequestration in vacuole (the proportions of Cd, Pb, Zn, and Hg in the soluble fractions are 50.99–59.00%, 41.05–45.46%, 37.54–61.04% and 33.47–61.35% in high metal concentration treatments) also act as important detoxification pathways. The external regulation was mainly the changes of soil microbial communities influenced by plants. Specifically, the richness and diversity of bacteria in rhizosphere soil were increased, and roots of S. nigrum L. recruited some potentially beneficial microbials. This study provided a theoretical basis and guidance for S. nigrum L. as a phytoremediation plant under combined heavy metal pollution.
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MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Ye Lin,Lingfen Yang,Ying Ma,Jianshan Ye
l -glutamate ( l -Glu) is the basic unit for the synthesis of protein, metabolic substances and chlorophyll, and plays an important role in the carbon and nitrogen metabolism in plants. The in vivo monitoring of l -Glu level is of great significance to study the growth and development of plants. Although a variety of methods have been reported for the in vitro determination of l -Glu, there are very limited research focused on the determination of l -Glu in plants. Here we firstly report a simple method to construct a minitype glutamate sensor for in vivo monitoring of l -glutamate in cucumber. The minitype graphite rod electrode (GRE) allows its application for in vivo monitoring, and modification of Pt nanoparticles (PtNPs) and poly ( m -phenylenediamine) film (PMPD) significantly improves the sensitivity and anti-interference ability, and immobilization of the glutamate oxidase (GluOx) could effectively catalyze the l -Glu into a detectable H 2 O 2 . The resulting l -Glu sensor exhibits a good performance in terms of high sensitivity, good selectivity and excellent stability with a linear range of 2–550 μM and limit of detection (LOD) as low as 0.536 μM. More importantly, the as-developed sensor was successfully applied for the determination of l -Glu in cucumber juice and the in vivo monitoring of l -Glu level in cucumber fruit. We envision that the constructed sensor will show great potentials for studying the growth mechanisms of plants.
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Food Chemistry-X
·
2023
·
IF 6.1
Dan Chen,Ao Wang,Jialiang Lv,Chao Tang,Chang-hai Jin,Jun Liu,Xiaoxiong Zeng,Li Wang
Tea ( Camellia sinensis L.) flower polysaccharides (TFPS) have various health-promoting functions. In the present work, the structure of a purified TFPS fraction, namely TFPS-1-3p, and its in vitro digestive properties were investigated. The results demonstrated that TFPS-1-3p was a typical heteropolysaccharide consisting of rhamnose (Rha), arabinose (Ara), galactose (Gal) and galacturonic acid (GalA) with a molecular weight of 47.77 kDa. The backbone of TFPS-1-3p contained → 4)-α- d -Gal p A(-6-OMe)-(1 → 4)-α-Gal p A-(1 → and → 4)-α- d -Gal p A(-6-OMe)-(1 → 2,4)-α- l -Rha p -(1 → linkages. The branch linkages in TFPS-1-3p contained → 6)-β- d -Gal p -(1→, →3,6)-β- d -Gal p -(1→, →5)-α- l -Ara f -(1 → and → 3,5)-α- l -Ara f -(1 →. Subsequently, TFPS-1-3p could not be degraded under simulated human gastrointestinal conditions but could be of use to human fecal microbes, thereby lowering the pH and increasing the production of short-chain fatty acids (SCFAs) of the gut microenvironment and altering the composition of the gut microbiota. The relative abundance of Fusobacterium_mortiferum Megasphaera_elsdenii_DSM_20460, Bacteroides thetaiotaomicron , Bacteroides plebeius and Collinsella aerofaciens increased significantly, potentially contributing to the degradation of TFPS-1-3p.
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PEST MANAGEMENT SCIENCE
·
2023
·Vol. 79
·期 12
·5270-5282
·
IF 4.1
Xi-Zhong Yan,Li Ma,Xiao-Fei Li,Le Chang,Qing-Zhao Liu,Cheng-Fei Song,Jin-Yu Zhao,Xing-Tao Qie,Cai-Ping Deng,Chen-Zhu Wang,Chi Hao
BACKGROUND The diamondback moth, Plutella xylostella , has developed resistance to almost all insecticides used for its control. The ‘push–pull’ method has been shown as an effective control strategy to address this resistance challenge of P. xylostella . The key focus of the strategy is the identification of attractive or repellent volatile components. The aim of this study was to identify attractive volatile compounds released from host plants. Identified compounds were applied in the biological control of this pest. RESULTS Nine active compounds released into the headspace of seven cruciferous plant species were identified using gas chromatography–electroantennographic detection and gas chromatography–mass spectrometry. Electroantennographic detection-active compounds included five green leaf volatiles (hexanal, trans -2-hexen-1-ol, cis -3-hexen-1-ol, cis -3-hexenyl acetate, and 1-penten-3-ol), three isothiocyanates (isopropyl isothiocyanate, allyl isothiocyanate, and butyl isothiocyanate), and nonanal. Except for nonanal, all the identified green leaf volatiles and isothiocyanates elicited strong electrophysiological and behavioral responses in P. xylostella . The strongest attractive compounds, trans -2-hexen-1-ol and isopropyl isothiocyanate, were further evaluated in oviposition and field-trapping assays. Results showed that they both lured female moths to lay eggs, and were highly attractive to P. xylostella adults in field, especially when used in combination with yellow and green sticky boards. However, a blend of the two compounds showed no synergistic effect, but rather an antagonistic effect. CONCLUSIONS Green leaf volatiles and isothiocyanates were identified as key olfactory cues for host selection of P. xylostella . Trans -2- hexen-1-ol and isopropyl isothiocyanate were identified as candidate attractive compounds to serve in a ‘push–pull’ strategy for P. xylostella control. © 2023 Society of Chemical Industry.
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