查找使用阿拉丁产品的科研文献

Antibiotic residues in cattle and sheep meat and human exposure assessment in southern Xinjiang, China

Yu Zhang,Jianjiang Lu,Yujun Yan,Jinhua Liu,Manli Wang

In recent years, antibiotics have become widely used in animal breeding. The application of antibiotics in livestock may lead to the presence of antibiotic residues in animal-derived foods, especially meat, that may pose a threat to human health. In this study, 26 common antibiotics (eight sulfonamides, nine fluoroquinolones, four tetracyclines, and five macrolides) were screened in 88 meat samples (cattle muscles and sheep muscles, kidneys, and livers) obtained from southern Xinjiang. The antibiotics were screened via the clean-up step based on solid-phase extraction and determined through ultraperformance liquid chromatography–tandem mass spectrometry. Moreover, their risk to human health was analyzed. Overall, 16 antibiotics were detected with a total detection rate of 95.46%. The percentage of noncompliant samples was 28.41% with an exceedance maximum residue limit of 1.14%. The illegal use rate of the antibiotic norfloxacin was 27.27%. The estimated daily exposure doses of all compounds in adults were <102.218 ng/kg bw/day even after applying the worst-case scenario approach. This result demonstrated that the antibiotic residues in the tested samples imposed negligible harm to people's health and had an acceptable level of food safety risk. However, the high detection frequencies found in this work indicated that the risk of antibiotic residues could not be ignored given the cumulative risk of antibiotics, particularly the emergence of bacterial resistance, to the human body. The need for effective strategies and publicity for the judicious use of antibiotics to safeguard residents’ health is immediate.

Cordycepin, a Characteristic Bioactive Constituent in Cordyceps militaris, Ameliorates Hyperuricemia through URAT1 in Hyperuricemic Mice

Yong Tianqiao,Chen Shaodan,Xie Yizhen,Chen Diling,Su Jiyan,Shuai Ou,Jiao Chunwei,Zuo Dan

Recently, we've reported the anti-hyperuricemic effects of Cordyceps militaris. As a characteristic compound of C. militaris, we hypothesized that cordycepin may play a role in preventing hyperurecimia. Remarkably, cordycepin produced important anti-hyperuricemic actions, decreasing SUA (serum uric acid) to 216, 210, and 203 μmol/L (P < 0.01) at 15, 30, and 60 mg/kg in comparison of hyperuricemic control (337 μmol/L), closing to normal control (202 μmol/L). Elisa, RT-PCR and western blot analysis demonstrated that the actions may be attributed to its downregulation of uric acid transporter 1 (URAT1) in kidney. Serum creatinine levels and blood urine nitrogen and liver, kidney, and spleen coefficients demonstrated that cordycepin may not impact liver, renal, and spleen functions. In addition, we used computational molecular simulation to investigate the binding mechanism of cordycepin. Of which, van der Waals interaction dominated the binding. Residues TRP290, ARG17, ALA408, GLY411, and MET147 contributed mainly on nonpolar energy. This provided the theoretical guidance to rationally design and synthesis novel URAT1 inhibitors.

Chemical composition and sources of amines in PM2.5 in an urban site of PRD, China

Shan Huang,Qicong Song,Weiwei Hu,Bin Yuan,Junwen Liu,Bin Jiang,Wei Li,Caihong Wu,Fan Jiang,Wei Chen,Xinming Wang,Min Shao

Atmospheric amines have attracted increasing attention due to their significant impact on new particle formation, particle hygroscopicity and particle optical properties . In this study, four low-molecule-weight amines were detected from PM 2.5 filter samples collected at an urban site of Pearl River Delta (PRD) region of China in 2018 autumn. During the campaign, the mass concentrations of ambient particulate methylamine (MA, CH 3 NH 2 ), dimethylamine (DMA, (CH 3 ) 2 NH), trimethylamine (TMA, (CH 3 ) 3 N), and diethylamine (DEA, (C 2 H 5 ) 2 NH) were quantified at daily or 12-h resolution using an optimized Ion Chromatograph (IC) method. The total measured amine concentration was 297 ± 209 ng/m 3 , which can account for 0.76 ± 0.33% of PM 2.5 mass concentrations. The particulate amines in PRD urban area were dominated by MA (243 ± 179 ng/m 3 ), accounting for over 80% of total amines, then followed by DMA (49 ± 30 ng/m 3 , 16.5%), TMA (4 ± 2 ng/m 3 ) and DEA (1 ± 1 ng/m 3 ). Based on the correlation analysis, MA and DMA mainly presented as nitrate and sulfate salts. We speculate the amines tend to react with gas-phase HNO 3 or particle-phase nitrate to form particulate amine salts via local process in Guangzhou. As the relative humidity (RH) increased, enhanced partitioning of amine towards the particle phase was observed. Using approach of multiple linear regression, 71% of the particulate amines in PRD urban site could be explained by acid-base process and the rest by primary emissions from combustion sources (29%).

Biomimetic mineralization of carboxymethyl chitosan nanofibers with improved osteogenic activity in vitro and in vivo

Xiujuan Zhao,Liangyu Zhou,Qingtao Li,Qingxia Zou,Chang Du

Inspired by the natural extracellular matrix, the organic-inorganic composite nanofibers are promising scaffolds for bone tissue engineering. Chitosan-based nanofibers are widely used as bone tissue engineering scaffolds with good biocompatibility but pungent solvents are frequently used for its processing. Carboxymethyl chitosan (CMCS), a water-soluble derivative of chitosan, has better biodegradability and bioactivity which allows CMCS to chelate Ca 2+ and induce the deposition of apatite. Moreover, with water as solvent, CMCS nanofibers avoid the acidic salt removal comparing to electrospun-chitosan. In this study, we successfully prepared uniform CMCS nanofibers with the aid of polyethylene oxide (PEO) and obtained the optimized conditions with a voltage of 25 kV and PEO of molecular weight 1000 kDa. We further prepared hydroxyapatite (HA) coated electrospun CMCS nanofibers by biomimetic mineralization using 5 times simulated body fluid. The promotion of osteogenic differentiation of mouse bone marrow stromal cells (mBMSCs) in vitro was evaluated on the nanofibers scaffolds. Cell experiments revealed that CMCS-HA composite nanofibers increased the ALP activity. The gene expression level of Runx2 and ALP were about 1.6 and 4.3 folds at the 7 days, and 5.1 and 10 folds at the 14 days on CMCS-HA nanofibrous membranes than that on CMCS alone samples. The level of OCN increased by 24 and 1.5 times on the CMCS-HA scaffolds than CMCS scaffolds at the 14 and 21 days. In vivo new bone formation by nanofiber scaffolds was investigated in a critical-size rat calvarial bone defect model. Micro-CT results showed that the whole defect was covered by new bone after CMCS-HA filling the defect for 12 weeks. The results of H&E staining and Masson’s trichrome staining on histological sections further confirmed that composite nanofibers promoted new bone formation and maturation.

In vitro and in vivo evaluation of didymin cyclodextrin inclusion complexes: characterization and chemosensitization activity

Qing Yao,Meng-Ting Lin,Qing-Hua Lan,Zhi-Wei Huang,Ya-Wen Zheng,Xue Jiang,Yin-Di Zhu,Longfa Kou,He-Lin Xu,Ying-Zheng Zhao

Synthesis and evaluation of antitumour activity in vitro and in vivo of chrysin salicylate derivatives

Xiangping Deng,Zihao Zhao,Shujuan Xiong,Runde Xiong,Juan Liu,Zhe Wang,Liu Zou,Xiaoyong Lei,Xuan Cao,Zhizhong Xie,Yanming Chen,Xing Zheng,Yunmei Liu,Guotao Tang

Ligustrazine Phosphate Ethosomes for Treatment of Alzheimer’s Disease, In Vitro and in Animal Model Studies

Shi Jun,Wang Yiming,Luo Guoan

In the present study, we have investigated transdermal administration of ligustrazine phosphate (LP), as an antioxidant, for the treatment of Alzheimer’s disease (AD). The LP transdermal ethosomal system was designed and characterized. Franz-type diffusion cells and confocal laser scanning microscopy were used for the in vitro permeation studies. Furthermore, the effect of LP transdermal ethosomal system on AD was evaluated in the scopolamine-induced amnesia rats by evaluating the behavioral performance in the Morris water maze test. The activities of the antioxidant enzymes and the levels of the lipid peroxidation product malondialdehyde (MDA) in the brain of rats were also determined. The results showed that both the penetration ability and the drug deposition in skin of the LP ethosomal system were significantly higher than the aqueous one. The LP transdermal ethosomal system could recover the activities of the antioxidant enzymes and the levels of MDA in the brain of the amnesic rats to the similar status of the normal rats, which was also indirectly reflected by the improvement in the behavioral performance. In conclusion, LP might offer a potential alternative therapeutic drug in the fight against AD, and ethosomes could be vesicles of choice for transdermal delivery of LP.

Preparation of Curcumin Micelles and the In Vitro and In Vivo Evaluation for Cancer Therapy

Li Xingyi,Chen Tongke,Xu Lu,Zhang Zhaoliang,Li Lingli,Chen Hao

Poor water solubility as well as poor bioavailability of curcumin has greatly hindered its applications in cancer therapy. In the present study, a highly water soluble curcumin nano-formulation was developed and its in vivo anti-cancer efficiency in nude BALB/c mouse model was evaluated. Unlike native curcumin, the developed curcumin micelles were quickly dissolved into aqueous solution with significant improvement of water solubility (∼104 fold increasement compared to its native form). The developed curcumin micelles had a narrow size distribution (18–28 nm) with high drug encapsulation efficiency (85%–95%). The developed curcumin micelles were characterized by X-raydiffraction (XRD), Differential scanning calorimetric (DSC), and Fluorescence spectral analysis. We observed the enhanced stability of curcumin in micelles formulation in phosphate buffer solution (PBS). In vitro cytotoxicity assay indicated that the curcumin micelles was comparatively more effective than native curcumin against various cancer cell lines due to the enhanced cellular uptake of curcumin yet resulting in the apoptosis of cancer cells. Western blotting study revealed that the induction apoptosis of S-65 cancer cells by curcumin micelles was mainly due to the down-regulation of p-Rb, Blc-2, p-AKT expression and caspase-9 activation. In vivo anti-tumor test in nude BALB/c mouse bearing S-65 xenografts indicated the intraperitoneal injection of curcumin micelles (25 mg/kg) could significantly inhibit tumor growth as compared with native curcumin treatment (p < 0.05), which was accompanied by significantly increased apoptosis of tumor cells and diminished vascular endothelial growth factor expression in tumor tissue (p < 0.05).

In Vitro and In Vivo Evidence for RNA Adduction Resulting from Metabolic Activation of Methyleugenol

Xiaojing Yang,Yukun Feng,Zhengyu Zhang,Hui Wang,Weiwei Li,Dan Ohtan Wang,Ying Peng,Jiang Zheng

Methyleugenol (ME) is a ubiquitous component in spices and other culinary herbal products. A prevailing theory in ME toxicity is its ability to be metabolically activated by P450 enzymes and sulfotransferases, which initiates sequential reactions of the resulting metabolites with functional biomolecules. The present study aimed at a potential interaction between the reactive metabolites of ME and RNA. Cultured mouse primary hepatocytes were incubated with ME followed by RNA extraction and NaOH and alkaline phosphatase-based RNA hydrolysis. Three adenosine adducts were detected in the hydrolytic mixture by LC–MS/MS. The same adenosine adducts were also detected in hepatic tissues harvested from ME-treated mice. These three adducts were chemically synthesized and structurally characterized by 1H NMR. Additionally, two guanosine adducts and one cytidine adduct were detected in the in vivo samples. These results provided solid evidence that the reactive metabolites of ME attacked RNA, resulting in RNA adduction.

Glutathione S-Transferase Genes are Involved in Lambda-Cyhalothrin Resistance in Cydia pomonella via Sequestration

Chao Hu,Ji-Yuan Liu,Wei Wang,David Mota-Sanchez,Shun He,Yu Shi,Xue-Qing Yang

Pest management is mostly accomplished by the use of insecticides. However, the overuse of insecticides has led to the development of resistance. Glutathione S-transferases (GSTs) are vital detoxification enzymes involved in insecticide resistance in insects. In this study, we report the involvement of GSTs in insecticide resistance to lambda-cyhalothrin in Cydia pomonella, a globally quarantined fruit pest. A total of 25 GST, including 22 cytosolic genes and 3 microsomal genes, are identified from the genome database of C. pomonella. These cytosolic genes are further classified into six classes, including four in delta, eight in epsilon, three in omega, three in sigma, one in theta, and one in zeta class, as well as two unclassified genes. The real-time quantitative polymerase chain reaction (RT-qPCR) shows that the majority of these genes are mainly expressed throughout the larval stage and in the midgut of the fourth-instar larvae. Exposure to an LD10 dose of lambda-cyhalothrin resulted in the upregulation of 17 GST genes. Moreover, mRNA levels of most GST genes, with the exception of CpGSTe6, CpGSTd2, CpGSTd4, and CpGSTz1, are considerably higher in a lambda-cyhalothrin-resistant population (ZW_R) than those of susceptible strains. Recombinant CpGSTd1, CpGSTd3, CpGSTe3, and CpGSTs2 can bind and metabolize lambda-cyhalothrin, with the highest metabolic rate observed for CpGSTd3 but no metabolite(s) was detected, supporting the role of GSTs in sequestration of lambda-cyhalothrin. Molecular dynamics simulation analysis indicates that key residues of hydrophobic pocket-derived lipophilic energy S(lipo) interactions with a hydrophobic pharmacophore of lambda-cyhalothrin are crucial for metabolism by CpGSTd3 and further lead to resistance. Our study is the first to experimentally confirm the involvement of GSTs in lambda-cyhalothrin resistance via sequestration and provides new insights into resistance management in C. pomonella.

Differential in vivo hemocyte responses to nano titanium dioxide in mussels: Effects of particle size

Ting Wang,Xizhi Huang,Xiaoyu Jiang,Menghong Hu,Wei Huang,Youji Wang

Titanium dioxide nanoparticles (TiO 2 NPs) are widely used in various products and inevitably released with different sizes and forms into aquatic environment. The purpose of this study was to assess the differential immune toxicity of TiO 2 NPs with size difference on mussel hemocytes using flow cytometry (FCM) assays. Hemocyte parameters, including total hemocyte count (THC), hemocyte mortality (HM), phagocytosis activity (PA), lysosomal content (LC), esterase activity (EA), mitochondrial number (MN), mitochondrial membrane potential (MMP) and reactive oxygen species content (ROS) were evaluated in the mussels Mytilus coruscus exposed to two types of TiO 2 NPs (25nm & 100nm: 0.1, 1, 10 mg/L, respectively). In general, size- and concentration-dependent toxicity was pronounced with 25nm-NP and highest concentration (10mg/L) being the most toxic. Alhough a slight recovery from the TiO 2 exposure was observed, significant carry-over effects were still detected. These results highlight the importance of differential size effects of metal oxide NPs on toxicity mechanisms in aquatic animals.

Development of Glass-sealed Gold Nanoelectrodes for in vivo Detection of Dopamine in Rat Brain

Shushu Ding,Yingzi Liu,Chunrong Ma,Junqi Zhang,Anwei Zhu,Guoyue Shi

In vivo monitoring of dopamine (DA) in cerebral nervous system with no traumatic brain injury is still a challenging work for reliably evaluating the role that DA plays in physical and cognitive functionality. In this work, to reduce the traumatic injury on the brain tissue, we develop a glass-sealed Au nanoelectrode (GSNE) with nanoscale physical dimention for cerebral DA detection. First, an Au microwire was sealed into the pre-thinned silica capillary. Then, the obtained Au/capillary assembly was pulled into two tips followed by polishing away the excess glass to expose the Au nanotip. The morphology of GSNE was characterized by scanning electron microscopy and transmission electron microscopy. The results showed that this nanoelectrode can be quickly fabricated with high reproducibility. By further electrodepositing cluster-like gold nanostructure on GSNE and modifying Nafion, amperometric detection of DA with high sensitivity and good selectivity were achieved on the Nafion-modified Au/GSNE. Moreover, the Nafion-modified Au/GSNE possessed advantages of easy tissue insertion and minimum tissue disturbance. Thus, the developed electrochemical nanosensor was successfully used for amperometrically monitoring DA level in the striatum of anesthetic rats.