Molecular Catalysis
·
2022
·
IF 5.089
Xinjian Yin,Wenzhong Gong,Zhigeng Zhan,Wei Wei,Mengmeng Li,Jianyu Jiao,Bishuang Chen,Lan Liu,Wenjun Li,Zhizeng Gao
Valine dehydrogenases (ValDHs) represent promising candidates for the development of biocatalysts for short chain amino acids or amines synthesis. However, only a limited number of ValDHs have been reported. Metagenomic mining is a powerful tool to access new members of limited enzyme families. Here we report the discovery of two novel ValDHs (HsValDH3 and HsValDH4) by metagenomic mining of a hot spring sediment sample. After systematical characterization and molecular dynamics simulations of HsValDH3 and HsValDH4, an interesting correlation between their structure compactness and thermostability was uncovered. We also identified a residue (I294) in the active pocket of HsValDH3 that plays a crucial role in its substrate specificity. Site-directed mutagenesis of this residue successfully shifted the substrate preference of HsValDH3, revealing a possible evolutionary route between ValDHs and LeuDHs. HsValDH3 and its mutant showed excellent catalytic efficiency and stereoselectivity in the synthesis of three valuable non-natural L -amino acids, highlighting their potential practical applications.
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RSC Advances
·
2014
·Vol. 4
·期 78
·41588-41596
·
IF 3.708
Lixin Yang,Xiuli Hu,Weiqi Wang,Shi Liu,Tingting Sun,Yubin Huang,Xiabin Jing,Zhigang Xie
Y-shaped amphiphilic block copolymers, (methoxy-poly(ethylene glycol))2-block-poly(L-glutamic acid) ((mPEG)2-PGA) and its precursor (methoxy-poly(ethylene glycol)2-block-poly(γ-benzyl-L-glutamate) ((mPEG)2-PBG), were prepared in three steps: (1) macroinitiator (methoxy-poly(ethylene glycol))2-NH2 ((mPEG)2-NH2) was synthesized by coupling two methoxy-poly(ethylene glycol)s with serinol and diisocyanate. (2) (mPEG)2-PBG was synthesized by ring opening polymerization of γ-benzyl-L-glutamate-N-carboxyanhydride initiated with the macroinitiator ((mPEG)2-NH2); (3) the protective benzyl groups in (mPEG)2-PBG were removed to obtain (mPEG)2-PGA. The properties of both (mPEG)2-PBG and (mPEG)2-PGA were characterized by 1H NMR, FT-IR, GPC, and DLS. In aqueous solution (mPEG)2-PBG tends to form more stable micelles compared to linear mPEG-PBG copolymer. The size of (mPEG)2-PBG decreases with increasing length of hydrophobic PBG in (mPEG)2-PBG. Paclitaxel and cisplatin were grafted onto (mPEG)2-PGA to form (mPEG)2-PGA-PTX (MPTX) with a grafting ratio of near 90% and (mPEG)2-PGA-Pt (MPt) conjugates with a loading efficacy of 15% (w/w). MPTX can greatly improve the solubility of PTX. Both conjugates can self-assemble into micelles with a mean diameter of about 50 nm and show enhanced anti-cancer activity against MCF-7, HeLa, and SMMC cell lines. The in vivo anticancer evaluation in mice shows MPt showed a desirable antitumor activity and allowed us to deduce the system toxicity. Therefore, both MPTX and MPt have a great potential as a polymer drug in cancer chemotherapy.
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Regenerative Biomaterials
·
2021
·Vol. 8
·期 5
·
IF 6.353
Liu Boxun,Jin Zhizhong,Chen Haiyan,Liang Lun,Li Yao,Wang Guo,Zhang Jing,Xu Tao
Electrospun membranes are attracting interest as a drug delivery system because of their material composition flexibility and versatile drug loading. In this study, the electrospun membrane was loaded with doxorubicin (DOX) via electrostatic adsorption for long-term drug delivery. DOX loading process was optimized by varying temperature, time, drug concentration, pH and ionic strength of solutions. The loading process did not impair the structural properties of the membrane. Next, we investigated the drug release kinetics using spectroscopic techniques. The composite membranes released 22% of the adsorbed DOX over the first 48 h, followed by a slower and sustained release over 4 weeks. The DOX release was sensitive to acidic solutions that the release rate at pH 6.0 was 1.27 times as that at pH 7.4. The DOX-loaded membranes were found to be cytotoxic to U-87 MG cells in vitro that decreased the cell viability from 82.92% to 25.49% from 24 to 72 h of co-incubation. These membranes showed strong efficacy in suppressing tumour growth in vivo in glioblastoma-bearing mice that decreased the tumour volume by 77.33% compared with blank membrane-treated group on Day 20. In conclusion, we have developed an effective approach to load DOX within a clinically approved poly (L-lactic acid)/gelatine membrane for local and long-term delivery of DOX for the treatment of glioblastoma.
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INORGANICA CHIMICA ACTA
·
2017
·
IF 2.002
Nan Zhang,Yuhua Fan,Guimei Huang,Daniela Buac,Caifeng Bi,Yanfei Ma,Xinping Wang,Zhen Zhang,Xia Zhang,Q. Ping Dou
Although cadmium is a widespread environmental contaminant and human carcinogen, our studies indicate an organic cadmium complex to be a potent inhibitor of proteasomal chymotrypsin-like (CT-like) activity, further capable of inducing apoptosis in a cancer cell-specific manner. Many clinical studies suggest the use of proteasome inhibitors as potential novel anticancer agents and in the present study, we have synthesized three novel l -tryptophan-containing cadmium complexes: Cd(C 17 H 15 N 4 O 2 ) 2 ·2CH 3 OH ( 1 ) (C 17 H 15 N 4 O 2 = 2-acetylpyrazine- l -tryptophan), Cd(C 17 H 15 N 2 O 3 ) 2 ·2CH 3 OH ( 2 ) (C 17 H 15 N 2 O 3 = 5-methylfurfural- l -tryptophan) and Cd(C 16 H 12 N 2 O 2 SBr) 2 ·2CH 3 OH ( 3 ) (C 16 H 12 N 2 O 2 SBr = 5-bromo-2-thiophenecarbaldehyde- l -tryptophan) and found that under comparable conditions cadmium complexes 1 and 2 , but not 3 , have proteasome-inhibitory activity in human breast cancer MDA-MB-231 cells. Our results suggest that l -tryptophan Schiff base cadmium complexes are potent proteasome inhibitors.
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JOURNAL OF DAIRY SCIENCE
·
2020
·
IF 3.333
Qianying Li,Guoyang Xie,Yutong Wang,Zoraida P. Aguilar,Hengyi Xu
ABSTRACT In this study, a new vancomycin (Van)-modified poly- l -lysine (PLL) magnetic bead (MB) technique was developed for isolation of gram-positive bacteria. The method combines magnetic separation with a multiplex PCR (mPCR) assay and gel electrophoresis for easy and rapid detection of Bacillus cereus . Vancomycin was used as a molecular ligand between the MB and the d -alanyl- d -alanine moieties on the cell wall surface of B. cereus . The PLL served as a flexible molecular tether between the MB and Van that reduced steric hindrance maintaining the biological activity of Van. The MB-PLL-Van capture nanoprobes exhibited excellent capture and isolation efficiency for B. cereus in spiked milk matrix samples without interference from the complex food matrix. The subsequent mPCR assay showed high specificity for the 4 target genes in B. cereus , the entFM , cesB , cer , and 16S rRNA genes, that were used to achieve efficient genotyping and detection. Under optimum conditions, the limit of detection reached 10 3 cfu/mL, with a dynamic range of detection at 10 3 to 10 7 cfu/mL in pure culture. Application of the MB-PLL-Van mediated mPCR assay for B. cereus in milk matrix samples achieved results similar to those of the pure culture. In addition, with a 6-h pre-enrichment of B. cereus that was spiked in milk matrix samples, the limit of detection reached 10 1 cfu/mL. The MB-PLL-Van mediated mPCR assay developed in this study could be used as a universal technology platform for the efficient enrichment and genotyping of gram-positive bacteria.
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ENVIRONMENTAL POLLUTION
·
2020
·
IF 6.793
Yuankun Liu,Min Lu,Qi Tao,Jipeng Luo,Jinxing Li,Xinyu Guo,Yongchao Liang,Xiaoe Yang,Tingqiang Li
The radial transport of cadmium (Cd) is essential for Cd influx in roots. The role of radial transport pathway on the Cd translocation from root to shoot among wheat genotypes are still poorly understood. This study explored the role of apoplastic and symplastic pathway on root Cd uptake and root-to-shoot translocation in Zhenmai 10 (ZM10, high Cd in grains) and Aikang 58 (AK58, low Cd in grains). Under Cd treatment, the deposition of Casparian strips (CSs) and suberin lamellae (SL) initiated closer to the root apex in ZM10 than that in AK58, which resulted in the lower Cd concentration in apoplastic fluid of ZM10. Simultaneously, Cd-induced expression levels of genes related to Cd uptake in roots were significantly higher in AK58 by contrast with ZM10, contributing to the symplastic Cd accumulation in AK58 root. Moreover, the addition of metabolic inhibitor CCCP noticeably decreased the Cd accumulation in root of both genotypes. Intriguingly, compared to ZM10, greater amounts of Cd were sequestrated in the cell walls and vacuoles in roots of AK58, limiting the translocation of Cd from root to shoot. Furthermore, the elevated TaHMA2 expression in ZM10 indicates that ZM10 had a higher capacity of xylem loading Cd than AK58. All of these results herein suggest that the radial transport is significant for Cd accumulation in roots, but it cannot explain the difference in root-to-shoot translocation of Cd in wheat genotypes with contrast Cd accumulation in grains.
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FISH & SHELLFISH IMMUNOLOGY
·
2021
·
IF 4.581
Min Gu,Shihui Pan,Wanzhen Deng,Qing Li,Zezheng Qi,Chuwen Chen,Nan Bai
Soya-saponins represent key anti-nutritional factors that contribute to soybean meal-induced enteritis , and glutamine is an effective fish intestine protectant that combats the negative effects of soya-saponins. Nuclear transcription factor-kappa B (NF-кB) systems are involved in the interactions between soya-saponins and glutamine, and the goal of the present work was to clarify the related molecular mechanisms used by the NF-кB kinase (IKK)/inhibitor of NF-κB (IκB)/NF-кB system. Primary cultured turbot ( Scophthalmus maximus L.) intestinal epithelial cells were concurrently administrated with 1 mg/mL of soya-saponins and several levels of glutamine (0, 0.5, 1.0 and 2.0 mM) for 12 h and then subjected to real-time PCR and Western blot assays. Compared with cells treated with soya-saponins alone, glutamine significantly decreased the expression of interleukin-1 beta, interleukin 8 and tumor necrosis factor α genes, significantly reduced nuclear and cytosolic NF-κB p65 abundance levels in a dose-dependent manner, increased the IκBα protein level but decreased its phosphorylation, and down-regulated the IKKα/β and phosphorylated IKKα/β levels. In conclusion, this in vitro work confirmed that glutamine attenuated soya-saponin-induced inflammatory responses in turbot intestines. Moreover, it identified molecular pathways in which glutamine first decreased the p65 level and then prevented its nuclear translocation. In addition, glutamine reduced IκBα phosphorylation and maintained its level. Finally, glutamine decreased IKK expression and phosphorylation.
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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
·
2021
·
IF 3.575
Ligang Xing,Yanmei Zhao,Mingzhu Gong,Xia Liu,Yuhui Zhang,Dan Li,Zefeng He,Ping Yan,Jidong Yang
In this study, Graphene Oxide (GO) was used to screen the binding with the aptamers of L-carnitine chiral enantiomers . The ssDNA library was prepared by the method of Lambda exonuclease . In addition, a simple casing device was designed to improve the purification and recovery efficiency of the small ssDNA fragments in the process of screening. Finally, more than 160,000 aptamer sequences were obtained by high-throughput sequencing. We determined the strongest affinity aptamer sequence, CA04, by the Resonance Rayleigh scattering (RRS) technology. We also analyzed the key binding sites (in the 16th position case) of the truncated aptamer sequence CAD10. Interestingly, we found that aptamer CA10 and CA06 were both C-rich bases through sequence alignment and analysis, and the aptamer CA10 was confirmed that the CA10 and CA06 were formed under acidic conditions (pH 4.5) by CD spectrum and ESI-MS analysis. The interaction between gold nanoparticles (AuNPs) and functionalized aptamer CA10 was analyzed. We used Site-directed mutagenesis design and QGRS Mapper to optimize aptamer CA10, where an optimal aptamer CA10-03 were obtained after affinity analysis. It is also proved to be an effective method to obtain stronger affinity aptamer. Meanwhile, Native-PAGE and UV spectrum analysis were performed on the mutation sequences, and the interaction with ThT was analyzed. Finally, it is hoped that my study can provide help for later identification and detection of L-carnitine .
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PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2019
·
IF 2.87
Chenyu Su,Xiaoming Xia
The diamondback moth (DBM), Plutella xylostella (L.), is a major pest affecting cruciferous vegetables, and seriously affects the quality and yield of these vegetables. Diafenthiuron is a traditional thiourea-based insecticide , but it is rarely used to control pests on cruciferous vegetables due to its phytotoxicity on these vegetables under high temperature and light conditions. Thus, there is an ongoing need for more effective pesticides that can be used on cruciferous vegetables, possibly including new formulations of diafenthiuron. A new thiourea insecticide, methylthio-diafenthiuron, is intended to optimize the structure of diafenthiuron not only to preserve its insecticidal bioactivity but also to overcome its phytotoxicity to cruciferous vegetables, aiming to control insect pests on cruciferous vegetables. In this study, we compared the toxicity of methylthio-diafenthiuron to some frequently used insecticides on the third-instar larvae of DBM. The parental pupal duration was significantly longer under the treatment than in the control, but the pupal weight, fecundity, and hatching rate significantly decreased. By studying the changes in three detoxifying enzymes within 72 h after treatment with a sublethal concentration, the activity of CarE and ODM in the treatment group significantly increased at first and then decreased. In addition, methylthio-diafenthiuron clearly inhibited three kinds of ATPases in the DBM and significantly reduced the eclosion rate of the pupae . This research provides valuable information for the assessment and rational application of methylthio-diafenthiuron for the control of pests on cruciferous vegetables.
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MOLECULES
·
2020
·Vol. 25
·期 19
·4507
·
IF 3.267
Zhen Li,Zongcai Tu,Hui Wang,Lu Zhang
Ceratophyllum demersumL. (CDL) is a traditional Chinese herb to treat many diseases, but research on its anti-diabetic activity is not available. In this research, the α-glucosidase inhibitory ability and phytochemical constituents of CDL extract were firstly studied. Optimal ultrasound-assisted extraction conditions for α-glucosidase inhibitors (AGIs) were optimized by single factor experiment and response surface methodology (RSM), which was confirmed as 70% methanol, liquid-to-solid ratio of 43 (mL/g), extraction time of 54 min, ultrasonic power of 350 W, and extraction temperature of 40 °C. The lowest IC50value for α-glucosidase inhibition was 0.15 mg dried material/mL (mg DM/mL), which was much lower than that of acarbose (IC50value of 0.64 mg DM/mL). In total, 80 compounds including 8 organic acids, 11 phenolic acids, 25 flavonoids, 21 fatty acids, and 15 others were identified or tentatively identified from CDL extract by HPLC-QTOF-MS/MS analysis. The results suggested that CDL could be a potential source of α-glucosidase inhibitors. It can also provide useful phytochemical information for research into other bioactivities.Keywords:Ceratophyllum demersumL.;response surface methodology;α-glucosidase inhibitors;phytochemical profile
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Foods
·
2022
·Vol. 11
·期 22
·3731
·
IF 5.561
Ziying Hu,Yanan Ma,Jun Liu,Yijun Fan,Anran Zheng,Pengyan Gao,Liang Wang,Dunhua Liu
Goji berry (Lycium barbarumL., LBL) is a good source of carotenoids, while the bioaccessibility of various types of LBL carotenoids has not been explored. In the study, eight carotenoids, three carotenoid esters and two carotenoid glycosylated derivatives were identified by a non−targeted metabolomics approach. The dried LBL (DRI), LBL in water (WAT), and LBL in “Baijiu” (WIN) were used to recreate the three regularly chosen types of utilization, and the in vitro digestion model showed that the bioaccessibility of the carotenoids increased significantly from the oral to the gastric and intestinal phase (p< 0.05). The bioaccessibility of LBL carotenoids was the most elevated for DRI (at 28.2%), followed by WIN and WAT (at 24.9% and 20.3%, respectively). Among the three carotenoids, zeaxanthin dipalmitate showed the highest bioaccessibility (51.8–57.1%), followed by β−carotene (51.1–55.6%) and zeaxanthin (45.2–56.3%). However, the zeaxanthin from DRI exhibited significantly higher bioaccessibility (up to 58.3%) than WAT and WIN in both the gastric and intestinal phases (p< 0.05). Results of antioxidant activity tests based on DPPH, FRAP, and ABTS showed that the addition of lipids improved the bioaccessibility of the carotenoids. (p< 0.05).Keywords:goji berry;bioaccessibility;carotenoids;metabolomics;zeaxanthin dipalmita
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3 Biotech
·
2021
·Vol. 11
·期 6
·1-14
·
IF 2.406
Appu Manikandan,Lian Zhifeng,Zhao Dengqi,Huang Jianying
In this study, we prepared chitosan (CS)-coated iron oxide (Fe 3 O 4 ) nanocomposites (NCs) by employing the aqueous leaf extract of Brassica oleracea L. and evaluated its antimicrobial potential. The characterization of hybrid CS-Fe 3 O 4 NCs was performed using Fourier-transform infrared spectroscopy (FTIR) analysis to evaluate the chemical bonding of chitosan to nanoparticles (NPs). X-ray photoelectron spectroscopy (XPS) studies revealed the presence of oxidation state elements Fe 2p, O 1s, N 1s, and C 1s, and the zeta potential analysis was found to have well-colloidal stability (+ 76.9 mV) of NCs. Transmission electron microscopy (TEM) analysis determined that CS-Fe 3 O 4 NCs were spherical with an average particle size of 27 nm. The X-ray diffractometer (XRD) spectrum ascertained the crystallinity of the hybrid NCs and the vibrating sample magnetometer (VSM) inferred the ferromagnetic behavior of the synthesized NCs. Furthermore, the significant antibacterial efficacy of NPs was demonstrated against foodborne bacterial pathogens, such as Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ), and the highest zone of inhibition was observed to be 11.5 mm and 13.5 mm in CS-Fe 3 O 4 NCs, respectively. In comparison with Fe 3 O 4 NPs, synergistic impacts of CS-Fe 3 O 4 NCs displayed great antibacterial potential as exhibited by a clearly enlarged zone. Thus, CS-Fe 3 O 4 NCs could be used as efficacious antimicrobial agents in food packaging and food preservation fields.
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危险品化学品经营许可证（带存储）