查找使用阿拉丁产品的科研文献

An anthracenecarboximide fluorescent probe for in vitro and in vivo ratiometric imaging of endogenous alpha-L-fucosidase for hepatocellular carcinoma diagnosis

Xianfeng Hou,Jin Peng,Fang Zeng,Changmin Yu,Shuizhu Wu

Alpha-L-fucosidase (AFU) plays vital roles in some physiological processes that closely relate to several diseases. Herein, a ratiometric fluorescent probe for the alpha-L-fucosidase (AFU) assay based on a single fluorophore has been developed by functionalizing a new fluorophore platform (6-bromo-anthracenecarboximide) with an α-L-fucose group. AFU cleaves the α-L-fucose group from the probe molecule and remarkably alters its photophysical properties, thus realizing ratiometric detection of AFU. Due to the specificity and high efficiency of the enzymatic reaction, this probe can sensitively and selectively detect AFU in aqueous media and biological milieus with a detection limit of 0.0033 U mL−1. Moreover, the probe can be employed to monitor and spatially map endogenous AFU levels in a hepatocellular carcinoma (HCC) model of zebrafish. Hence, the probe holds significant promise for conducting pathological research on AFU-involved diseases.

Green and efficient synthesis of carbon quantum dots from cordia myxa L. and their application in photocatalytic degradation of organic dyes

Morvarid Najjar,Mohammad Ali Nasseri,Ali Allahresani,Majid Darroudi

In this work, carbon quantum dots (CQDs) were synthesized through a simple and green hydrothermal method with the usage of green materials. The synthesis of CQDs was confirmed by the results of various analyses such as XRD, EDX, FT-IR, and UV–Vis, while their size and morphology were determined by the TEM and FESEM images. This product contained a pseudo spherical morphology with an average size of 2.2 nm. The good photoluminescence (PL) intensity and quantum yield (QY) of the CQDs were confirmed using the PL spectra. Furthermore, the photocatalytic activity of the prepared CQDs was examined in the degradation of the four organic dyes including methylene blue (MB), crystal violet (CV), methyl orange (MO), and eriochrome black T (EBT) under UV irradiation, while the effective parameters including pH, amount of photocatalyst, and dye concentration were optimized.

Bright Mn-doped carbon dots for the determination of permanganate and L-ascorbic acid by a fluorescence on-off-on strategy

Chu Xu,Ning Gan,Zhou Zhiqiang,Liu Yi,Xiao Qi,Huang Shan

A one-pot hydrothermal synthesis of manganese-doped carbon dots (Mn-CDs) is reported for fluorescent “on-off-on” determination of Mn(VII) and L-ascorbic acid (L-AA) in aqueous solution and living cells. Mn-CDs were prepared by using sulfanilic acid, tetrakis(hydroxymethyl)phosphonium chloride, and Mn(II) chloride as precursors. Mn-CDs were characterized by several spectroscopic methods and microscopic techniques. Mn-CDs show distinctly long fluorescence lifetime (12.39 ± 0.07 ns) and high absolute fluorescence quantum yield (around 37%) with excitation and emission wavelengths of 362 and 500 nm, respectively. Mn-CDs exhibit no significant cytotoxicity to human cervical carcinoma HeLa cells and human embryonic kidney HEK-293T cells at 200 μg mL −1 level after 48 h incubation. The fluorescence of Mn-CDs at 500 nm (excited at 362 nm) is quenched efficiently by Mn(VII) and can be further recovered after the addition of L-AA, resulting in a fluorescent “on-off-on” assay for the determination of Mn(VII) and L-AA. Under optimal experimental conditions, the linear response covers the 3 to 150 μM Mn(VII) concentration range and the 3 to 140 μM L-AA concentration range. This method offers relatively low detection limits of 0.66 μM for Mn(VII) and 0.90 μM for L-AA. This strategy was applied to visual determination of Mn(VII) and L-AA in living HeLa cells with satisfying results. Schematic presentation of bright Mn-CD-based fluorescence “on-off-on” assay for both Mn(VII) and L-AA. This fluorescent assay possessed low detection limit of 0.66 μM for Mn(VII) and 0.90 μM for L-AA. This strategy was applied for visual determination of Mn(VII) and L-AA in living HeLa cells with satisfying results.

Kinetic study on the generation of furosine and pyrraline in a Maillard reaction model system of d-glucose and l-lysine

Hang Yu,Qili Zhong,Yunfei Xie,Yahui Guo,Yuliang Cheng,Weirong Yao

A kinetic model for Maillard reaction (MR) model system of d -glucose and l -lysine was established; activation energy ( Ea ) of each step was calculated. Potential generation pathways of furosine and pyrraline were a combination of either 3-deoxyglucosone (3-DG) or methylglyoxal (MG) with l -lysine. Ea value for furosine generated through 3-DG pathway was 81.70 ± 14.01 kJ mol −1 , which was significantly higher than that through MG pathway (52.08 ± 4.48 kJ mol −1 ). As for pyrraline, Ea for the 3-DG pathway (53.45 ± 4.02 kJ mol −1 ) was significantly lower than that through the MG pathway (110.22 ± 18.77 kJ mol −1 ). Results of the kinetic study indicated that furosine was preferred to be generated through the MG pathway since MG is more likely to react with each other and form a furan ring as a precursor of furosine. Pyrraline was more easily to be generated from the 3-DG pathway through cyclization of 1,4-dicarbonyl compounds to pyrrole.

Highly sensitive “turn-on” fluorescent chemical sensor for trace analysis of Cr3 + using electro-synthesized poly(N-(9-fluorenylmethoxycarbonyl)-l-histidine)

Hui Zhang,Ge Zhang,Jingkun Xu,Yangping Wen,Shouli Ming,Jie Zhang,Wanchuan Ding

Trivalent chromium (Cr 3   + ) can cause severely environment pollution, declining quality of edible agro-products in plants and animals, and human diseases. Poly( N -(9-fluorenylmethoxycarbonyl)- l -histidine) (PFLH) synthesized by the direct electro-polymerization of its corresponding commercially available monomer in both boron trifluoride diethyl etherate and dichloromethane mixed system. The “turn-on” type fluorescent sensor based on PFLH displayed high sensitivity and selectivity for Cr 3   + detecting. The structure of PFLH was rationally proved by 1 H NMR spectra, FT-IR spectra, quantum chemical calculations , and its optical properties were characterized. The electro-synthesized PFLH exhibited a “turn-on” fluorescent response towards Cr 3   + , which was employed as a sensing platform for the “turn-on” fluorescent analysis of Cr 3   + in a wide linear range from 5.1   nM to 25   μM with a low limit of detection as low as 1.7   nM. The possible mechanism of fluorescent “turn-on” sensor based on PFLH for Cr 3   + was proposed. The sensor displayed high sensitivity, good selectivity, satisfactory practicability, suggesting that PFLH has potential fluorescent application for “turn-on” sensing Cr 3   + in agricultural environments and edible agro-products of plants and animals.

Effect of l-histidine on the heat-induced aggregation of bighead carp (Aristichthys nobilis) myosin in low/high ionic strength solution

Ruichang Gao,Yanmin Wang,Jianlou Mu,Tong Shi,Li Yuan

In this study, the effects of l -histidine (L-His) on the aggregation of bighead carp ( Aristichthys nobilis ) myosin induced by heating in low (0.1) or high (0.5) ionic strength solutions were studied. The solubility of natural myosin was significantly enhanced by L-His both in low and high ionic strength solutions. More small particles are suspended in the heated solution containing L-His, inducing a higher solubility than that solution without L-His. The surface hydrophobicity of myosin in a low ionic strength solution containing L-His is higher than that of myosin without L-His. The results of morphology show that L-His induced myosin to form finer aggregates and a honeycomb-like network in a low/high ionic strength solution during heat treatment. These results demonstrate that L-His might disrupt the electrostatic property of unfolded myosin heat-induced through electrostatic binding with the exposed negatively charged amino acid residues, which might disarrange hydrophobic surfaces, resulting in weakening hydrophobic interactions, which ultimately suppresses the fierce aggregation of carp myosin.

Epsilon-poly-l-lysine decorated ordered mesoporous silica contributes to the synergistic antifungal effect and enhanced solubility of a lipophilic drug

Yiyan Song,Ping Zhu,Yuan Wu,Li Tan,Wei Wei,Songqin Liu,Qing Huang,Jin Chen

The emergence of drug-resistant fungal strains remains a severe threat for the public health, which prompts strict restrictions on the uses of antifungal drugs. However, the majority of lipophilic fungistatic agents are poorly water soluble with a low oral adsorption characteristic posing challenges for the precise prescriptions. In this study, a natural antimicrobial cationic peptide of epsilon-poly- l -lysine (EPL) decorated ordered mesoporous silica (SBA-15) was facilely prepared for the efficient loading of antifungal itraconazole (ITZ) drugs. The characterized mesoporous SBA-15/EPL/ITZ composite exhibited remarkable antifungal performance against Aspergillus fumigatus as a model mold, which was attributed to synergistic antifungal activities of ITZ and EPL in the mesopores. Moreover, the in vitro release behaviors of ITZ in the composite nanoexcipients both in simulated gastric fluid and fasted state simulated intestinal fluid were studied. The observed release kinetics of ITZ demonstrated a contributing role of SBA-15/EPL to enhance the solubility of ITZ and thereby may promote its flux across the gastrointestinal epithelium, which is beneficial for the absorption of drugs. Additionally, SBA-15/EPL/ITZ composites showed desirable biocompatibility toward mammalian red blood cells, human cervical cancer cells (Hela) and human embryonic kidney cells (HEK-293T). Furthermore, the pharmacokinetic profiles of obtained nano-formulations were assessed in rats, among which the improved adsorption of SBA-15/EPL/ITZ composites (AUC 0–24h sum : 8381.7 nM·h) was identified compared with that of pure ITZ (525.1 nM·h) and the commercial drug of Sporanox (7516.6 nM·h). Collectively, the prepared SBA-15/EPL/ITZ provides an ecofriendly and integrated nanocomposite with enhanced solubility of lipophilic drugs to combat proliferations of infectious fungi.

Idarubicin-loaded methoxy poly(ethylene glycol)-b-poly(l-lactide-co-glycolide) nanoparticles for enhancing cellular uptake and promoting antileukemia activity

Bin Liang,Na Li,Shuofei Zhang,Aihua Qi,Jianhua Feng,Weiwei Jing,Changcan Shi,Zhaipu Ma,Shenmeng Gao

Synthesis of a mace-like cellulose nanocrystal@Ag nanosystem via in-situ growth for antibacterial activities of poly-L-lactide scaffold

Cijun Shuai,Xun Yuan,Wenjing Yang,Shuping Peng,Guowen Qian,Zhenyu Zhao

Antibacterial property for scaffolds is an urgent problem to prevent infections in bone repair. Ag nanoparticles possess excellent bactericidal activities, whereas their agglomeration restricts the full play of antibacterial property in scaffold. Herein, a mace-like nanosystem was constructed to improve their dispersion by in-situ growth of Ag nanoparticles on cellulose nanocrystal (CNC), which was labeled CNC@Ag nanosystem. Subsequently, the CNC@Ag nanosystem was introduced into poly-L-lactide (PLLA) scaffolds. Results demonstrated that the nanosystem uniformly dispersed in scaffold. The antibacterial tests demonstrated that the scaffolds possessed robust antibacterial activities against E. coli , with bacterial inhibition rate over 95%. Moreover, ion release behavior corroborated the scaffolds continuously released Ag + for more than 28 days, which benefited from the immobilization effect of CNC on Ag. Encouragingly, the mechanical properties of the scaffolds were remarkably higher than that of PLLA/CNC scaffolds, owing to the mace-like CNC@Ag nanosystem improved the load transfer efficiency in the scaffold.

Isolation and characterization of plant growth-promoting rhizobacteria and their effects on the growth of Medicago sativa L. under salinity conditions

Zhu Zhiyu,Zhang Huanhuan,Leng Jing,Niu Huanqing,Chen Xiaochun,Liu Dong,Chen Yong,Gao Nan,Ying Hanjie

Plant growth-promoting rhizobacteria are a group of free-living bacteria that colonize plant rhizosphere and benefit plant root growth, thereby increasing host plant to cope with salinity induced stress. The aim of this study was to (1) isolate and characterize auxin-producing bacteria showing a high plant growth-promoting (PGP) potential, and (2) evaluate the PGP effects on the growth of Medicago sativa L under salinity stress (130 mM NaCl). Of thirteen isolates, Bacillus megaterium NRCB001 (NRCB001), B. subtilis subsp . subtilis NRCB002 (NRCB002) and B. subtilis NRCB003 (NRCB003) had the ability to produce auxin, which ranged from 47.53 to 154.38 μg ml −1 . The three auxin-producing bacterial strains were shown multiple PGP traits, such as producing siderophore and NH 3 , showing ACC deaminase activity, solubilize phosphate and potassium. Furthermore, NRCB001, NRCB002, and NRCB003 could survive in LB medium containing 1750 mM NaCl. The three auxin-producing with salinity tolerance strains were selected for further analyses. In greenhouse experiments, when inoculated with NRCB001, NRCB002 and NRCB003, dry weight of alfalfa significantly ( P  < 0.05) increased by 24.1%, 23.1% and 38.5% respectively, compared with those of non-inoculated control seedlings under normal growth condition. When inoculated with NRCB002 and NRCB003, dry weight of alfalfa significantly ( P  < 0.05) increased by 96.9 and 71.6% respectively, compared with those of non-inoculated control seedlings under 130 mM NaCl condition. Our results indicated that NRCB002 and NRCB003 having PGP traits are promising candidate strains to develop biofertilizers, especially used under salinity stress conditions.

Effects of long-term blue light irradiation on carotenoid biosynthesis and antioxidant activities in Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Ruixing Zhang,Wenjing Yang,Qiming Pan,Qi Zeng,Chengtai Yan,Xue Bai,Yao Liu,Lugang Zhang,Baohua Li

The aim of this study was to investigate the impact of long-term exposure to blue light-emitting diodes (LEDs) on the accumulation of indolic glucosinolates and carotenoids, as well as the plant growth and antioxidant activities in both orange and common Chinese cabbage ( Brassica rapa L. ssp. pekinensis ). Blue light treatment also induced higher ferric-reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl by 20.66 % and 30.82 % and antioxidant enzyme activities catalase, peroxidase, superoxide dismutase, and the accumulation of non-enzymatic antioxidant substances (total phenols and total flavonoids) in the orange Chinese cabbage. Furthermore, long-term exposure to blue light had negative effects on the net photosynthetic rate and chlorophyll fluorescence levels. Meanwhile, blue light promoted accumulation of Indol-3-ylmethyl glucosinolate (I3M), β-carotene, lutein and zeaxanthin due to the high expression of regulatory and biosynthetic genes of the above metabolic pathways. In particular, lycopene and β-carotene content in orange Chinese cabbage increased by 60.14 % and 65.33 % compared to the ones in common line. The accumulation of carotenoid and increasing antioxidant levels in the orange cabbage line was influenced by long-term blue light irradiation, leading to better tolerance to low temperature and drought stresses. The up-regulation of transcription factors such as BrHY5-2 , BrPIF4 and BrMYB12 may also contribute to the increased tolerance in orange Chinese cabbage to extreme environmental stresses. The BrHY5-2 gene could activate carotenoid biosynthetic genes and induce the accumulation of carotenoids. These findings suggested that long-term blue light irradiation could be a promising technique for increasing the nutrition value and enhancing tolerance to low temperature and drought stresses in Chinese cabbage.

Effects of adding L-cysteine on the accumulation of the main compounds and their new analogs in roasting Coffea arabica beans

Hong Wang,Yan Li,Wenli Zhao,Yu Wang,Jinqian Pang,Li Wan,Qipeng Zhang,Wenjuan Liang

Hazardous substances such as acrylamide (AA) are easily produced by the Maillard reaction during coffee roasting. By adding l -cysteine ( l -Cys), the production of AA was inhibited whereas the profiles of the newly formed compounds remain unclear. To elucidate the influence of l -Cys addition on the main characteristic compounds of Yunnan Coffea arabica , investigations using LC-MSⁿ-IT-TOF, FTIR and assays of in vitro antioxidant and xanthine oxidase (XO) inhibitory activities were carried out. The result revealed that the most characteristic compounds represented by the chlorogenic acid analogs (CGAs) were critical to hazards formation during the Maillard reaction. Adding l -Cys before roasting enhanced coffee quality by reducing harmful intermediates such as 5-hydroxymethylfurfural (5-HMF) while increasing bio-potentials. New compound N6 which was formed by the addition of l -Cys and CGAs, together with the flavonoids generated through polymerization and simple phenols derived from thermal cleavage, were mainly contributed to the above potential.