查找使用阿拉丁产品的科研文献

Two-stage biosynthesis of D-tagatose from milk whey powder by an engineered Escherichia coli strain expressing L-arabinose isomerase from Lactobacillus plantarum

Guoyan Zhang,Hossain M. Zabed,Junhua Yun,Jiao Yuan,Yufei Zhang,Yang Wang,Xianghui Qi

In this study, a new strain of Lactobacillus plantarum (CY.6) was identified and its L-arabinose isomerase (L-AI) encoding gene ( ara A) was overexpressed in Escherichia coli BL21 for the biosynthesis of D-tagatose from milk whey powders (WP). Whole-cell biotransformation of lactose in WP into D-tagatose was done by three technological approaches, including 100%, 50% and 0% hydrolysis of lactose in WP before biotransformation, where simultaneous saccharification and biotransformation (SSB, 0% prior hydrolysis of lactose) produced maximum amounts of D-tagatose. Two-stage SSB provided 73.6% conversion efficiency (based on D-galactose) and 36.8% (in term of lactose), with 51.5 g/L of D-tagatose after 96 h, while concentration of D-tagatose produced after first stage was 34.4 g/L. Yield and volumetric productivity of D-tagatose after two-stage SSB were found to be 0.26 g/g of WP (0.37 g/g of lactose, 0.74 g/g of D-galactose produced from lactose) and 0.54 g/L/h, respectively.

Phenylboronic Acid-Modified Near-Infrared Region Ii Excitation Donor–Acceptor–Donor Molecule for 2-Deoxy-D-Glucose Improved Starvation/Chemo/Photothermal Combination Therapy

Pengfei Sun,Wan Yang,Jiarong He,Liuliang He,Pengfei Chen,Wenjuan Xu,Qingming Shen,Daifeng Li,Quli Fan

Cancer seriously affects the quality of life of patients with the disease. Synergistic chemotherapy and photothermal therapy (PTT) have emerged as a promising anticancer paradigm to achieve expected therapeutic effects while mitigating side effects. However, the chemo/PTT combination therapy suffers from limited penetration depth, thermo-resistance performance of tumor cells, and low drug bioavailability. Herein, we developed multifunctional nanoparticles (BTP/DOX/2DG NPs) coloaded with near-infrared region II (NIR-II) light excitation donor–acceptor–donor (D-A-D) small molecules, doxorubicin (DOX), and 2-deoxy-D-glucose (2-DG) for reinforced starvation/chemo/NIR-II PTT combination therapy. Our synthesized phenylboronic acid (PBA)-modified water-soluble D-A-D molecule (BBT-TF-PBA) not only exhibits high binding ability to DOX and 2-DG through donor–acceptor coordination interactions PBA-diol bonds but also serve as a photoactive agent for NIR-II fluorescence imaging, NIR-II photoacoustic imaging, and NIR-II PTT. Under the acidic and oxidizing conditions in the tumor microenvironment, donor–acceptor coordination interactions and PBA-diol bond are decomposed, simultaneously releasing DOX and 2-DG from BTP/DOX/2DG NPs to achieve effective chemotherapy and starvation therapy. 2-DG also effectively inhibits the expression of heat shock protein and further enhances NIR-II PTT and chemotherapy efficiency. In vitro and in vivo experiments demonstrated the combination effect of BTP/DOX/2DG NPs for chemotherapy, NIR-II PTT, and starvation therapy. This article is protected by copyright. All rights reserved

Small Molecular Weight Aldose (d-Glucose) and Basic Amino Acids (l-Lysine, l-Arginine) Increase the Occurrence of PAHs in Grilled Pork Sausages

Wen Nie,Ke-zhou Cai,Yu-zhu Li,Shuo Zhang,Yu Wang,Jie Guo,Cong-gui Chen,Bao-cai Xu

(1) Background: Amino acids and carbohydrates are widely used as additives in the food industry. These compounds have been proven to be an influencing factor in the production of chemical carcinogenic compounds polycyclic aromatic hydrocarbons (PAHs). However, the effect of the properties of the amino acids and carbohydrates on the production of PAHs is still little known. (2) Methods: We added different (i) R groups (the R group represents an aldehyde group in a glucose molecule or a ketone group in a fructose molecule); (ii) molecular weight carbohydrates; (iii) polarities, and (iv) acid-base amino acids to pork sausages. The effects of the molecular properties of carbohydrates and amino acids on the formation of PAHs in grilled pork sausages were investigated. (3) Results: The results showed that a grilled sausage with aldehyde-basedd-glucose was capable of producing more PAHs than a sausage with keto-basedd-fructose. A higher PAH content was determined in the grilled pork sausage when the smaller molecular weight,d-glucose, was added compared with the sausage where the larger molecular weight, 4-(α-d-glucosido)-d-glucose and cellulose were added. The addition of basic amino acids (l-lysine,l-arginine) was capable of producing more PAHs compared with the addition of acidic amino acids (l-glutamic acid,l-aspartate). When amino acid containing a benzene ring was added, a smaller volume of PAHs was produced compared with the addition of other amino acids. (4) Conclusions: Our study suggests that systematic consideration of molecule properties is necessary when using food additives (amino acids and carbohydrates) for food processing.Keywords:amino acids;carbohydrates;acidity;polarity;molecular weight

Well-ordered chitin whiskers layer with high stability on the surface of poly(d,l-lactide) film for enhancing mechanical and osteogenic properties

Wenjun Liu,Ling Zhu,Yunfa Ma,Lihao Ai,Wei Wen,Changren Zhou,Binghong Luo

In order to better utilize and combine the advantages of poly( d , l -lactide) (PDLLA) matrix and natural polysaccharide chitin whiskers (CHWs), needle-like CHWs with chiral nematic liquid crystal characteristics and remarkable moduli were chosen to surface modify PDLLA film. By a vertical coating method, a stable and well-ordered CHWs coating was formed on the surface of the PDLLA film through a polydopamine (PDA) interlayer. The high stability of the well-ordered CHWs coating on the surface of the PDLLA film was confirmed by PBS soaking experiment in terms of the changes of weight and surface morphology of the film. The surface microstructure and composition of the resulting PDLLA-PDA-CHWs film were characterized by field emission scanning electron microscopy (FESEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and the thickness of the PDLLA, PDA and CHWs layers was determined using FESEM, too. Comparing with traditional PDLLA/CHWs film, prepared by solution blending with optimal content of 5 wt% CHWs, the hydrophilicity and mechanical properties of the PDLLA-PDA-CHWs film were significantly improved owing to the immobilization of a highly ordered CHWs coating. Furthermore, in vitro cell culture showed that the well-ordered CHWs coating had a more significant effect on promoting the adhesion, spreading, proliferation and osteogenic differentiation of MC3T3-E1 cells. All these results showed that the resulting PDLLA-PDA-CHWs film with well-ordered CHWs coating designed through simple and effective approach has promising application in bone repair material field.

Synergistic anti-breast cancer effect of pulsatilla saponin D and camptothecin through interrupting autophagic–lysosomal function and promoting p62-mediated ubiquitinated protein aggregation

Wang Kai,Tu Yanbei,Wan Jian-Bo,Chen Meiwan,He Chengwei

Autophagy is an evolutionarily conserved mechanism to protect the cells from unfavorable environmental conditions. Inhibition of autophagy has been contemplated as a novel strategy to enhance anticancer efficacy of existing chemotherapeutic agents. We previously reported that pulsatilla saponin D (PSD) was a potent autophagy inhibitor. However, its anticancer potential as adjuvant and underlying mechanisms are still unknown. In this study, we identified that PSD induced the formation of autophagosome in MCF-7 and MDA-MB-231 breast cancer cells. However, PSD alone and particularly co-treatment with camptothecin remarkably increased p62 protein levels, indicating that PSD strongly inhibited the autophagic cargo degradation. The mechanistic study indicated that PSD profoundly abolished the co-localization of EGFP-LC3 and lysosomal-specific probe LysoTracker Red, suggesting that the autophagosome–lysosome fusion was blocked by PSD, which is similar to the action of chloroquine. In addition, PSD significantly increased lysosomal pH and inhibited the activation of lysosomal cathepsins in both breast cancer cell lines. Furthermore, the accrued p62 resulted in accumulation of ubiquitinated proteins owing to the interaction with p62 and delivery to the malfunctioned autophagosome by PSD. Finally, we demonstrated that PSD synergistically enhanced the anticancer activity of camptothecin (CPT) in cultured breast cancer cells and in mouse xenograft tumor models. Our results indicated that PSD inhibited autophagic flux via blocking autophagosome–lysosome fusion and lysosomal acidification, which may confer a synergistic anti-breast cancer activity of PSD and CPT.

Rapid determination of 3′, 4′-dimethoxy flavonol-3-β-d-glucopyranoside in rat plasma by LC-MS/MS method followed by protein precipitation

Qiong Lou,Jun Wen,Yuanying Jiang,Jinghua Huang,Guorong Fan,Fenyun Song

A reliable liquid chromatography/tandem mass (LC-MS/MS) method was developed for quantitation of 3′, 4′-dimethoxy flavonol-3-β- d -glucopyranoside (DF3G) in rat plasma using pantoprazole as the internal standard. An Agilent C18 column (100 mm × 3 mm, 3.5 μm) was performed for chromatographic separation with the mobile phase composed of methanol-water (containing formic acid) at a flow rate of 0.4 mL/min. A triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source in positive ion mode was applied to quantitative analysis by multiple reacting monitoring (MRM). The MRM precursor-product ion transition of DF3G and Pantoprazole (IS) were m / z 461.1 → 299.2 and 383.9 → 200.2, respectively. Calibration curves were recovered in a concentration range of 1–500 ng/mL for plasma with a limit of lower quantification (LLOQ) of 1 ng/mL. The intra-day and inter-day precision were not >10%. The accuracy of DF3G ranged from −10% to 0.53% in quality control (QC) samples at three concentrations. DF3G was not degraded during the analysis and the storage period. All the data were validated in accordance with the FDA bioanalytical method validation guideline. The LC-MS/MS method was successfully employed in the pharmacokinetic study of the DF3G after oral administration and intravenous injection in rats.

Calycosin‑7‑O‑β‑D‑glucoside downregulates mitophagy by mitigating mitochondrial fission to protect HT22 cells from oxygen‑glucose deprivation/reperfusion‑induced injury

Xiangli Yan,Siqi Quan,Roujia Guo,Zibo Li,Ming Bai,Baoying Wang,Pan Su,Erping Xu,Yucheng Li

Calycosin‑7‑O‑β‑D‑glucoside (CG), a major active ingredient of Astragali Radix, exerts neuroprotective effects against cerebral ischemia; however, whether the effects of CG are associated with mitochondrial protection remains unclear. The present study explored the role of CG in improving mitochondrial function in a HT22 cell model of oxygen‑glucose deprivation/reperfusion (OGD/R). The Cell Counting Kit‑8 assay, flow cytometry, immunofluorescence and western blotting were performed to investigate the effects of CG on mitochondrial function. The results demonstrated that mitochondrial function was restored after treatment with CG, as indicated by reduced mitochondrial reactive oxygen species levels, increased mitochondrial membrane potential and improved mitochondrial morphology. Overactivated mitophagy was revealed to be inhibited by the regulation of proteins involved in fission [phosphorylated‑dynamin‑related protein 1 (Drp1) and Drp1] and mitophagy (LC3, p62 and translocase of outer mitochondrial membrane 20), and mitochondrial biogenesis was demonstrated to be enhanced by increased levels of sirtuin 1 (SIRT1) and peroxisome proliferator‑activated receptor γ coactivator‑1α (PGC‑1α). In addition, neuronal apoptosis was ameliorated by CG, as determined by a decreased rate of apoptosis, and levels of caspase‑3 and Bcl‑2/Bax. In conclusion, the present study demonstrated that CG may alleviate OGD/R‑induced injury by upregulating SIRT1 and PGC‑1α protein expression, and reducing excessive mitochondrial fission and overactivation of mitophagy.

A novel fluorescent “Off-On” probe based on phenanthro[9,10-d]imidazole conjugated polymers (PIPF) for Cr3+ detection with high selectivity and sensitivity

Mingyi Guan,Hui Li,Man Tu,Chenchen Fu,Xiyu Yang,Feng Wang

Trivalent chromium (Cr 3+ ) causes serious environmental pollution, degradation of the quality of edible agricultural products and human diseases. A novel phenanthro[9,10-d]imidazole-derived conjugated polymers (PIPF) was obtained from 4-(5,10-dibromo-1H-phenanthro[9,10-d]imidazol-2-yl)phenol and diethyl 4,4′-(2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluorene-9,9-diyl)dibutyrate by Suzuki polymerization reaction, which was reasonably demonstrated by 1 H NMR spectroscopy, infrared spectroscopy and quantum chemical calculations. The PIPF exhibits a “turn-on” fluorescence response to Cr 3+ in DMSO/H 2 O (98:2, v/v) with naked-eye detection. The limit of detection for Cr 3+ was calculated to be 0.073 μM with a linear range of 3–9 μM. The possible mechanism of the PIPF-based Cr 3+ fluorescence “turn-on” sensor is due to the inhibition of the PET process by the coordination of Cr 3+ to the hexaalkyl ester carbon chain of PIPF (RCOO-). The high sensitivity, good selectivity, and utility of this sensor indicated that PIPF-based “turn-on” fluorescence sensor is a potential fluorescence application for measuring Cr 3+ in environmental samples.

ATP Inhibition for Starvation/Mild Photothermal/Photodynamic Synergy Therapy Using Polypeptide Nanoparticles Conjugating 2-Deoxy-D-Glucose and Dye under NIR Phototheranostic Strategy

Yixuan Xu,Huiping Dang,Changchang Teng,Dalong Yin,Lifeng Yan

Rapid propagation of tumor cells requires plenty of energy, which is adenosine triphosphate (ATP) dependent. ATP inhibition in tumors not only results in the starvation of tumor cells but also down-regulation of the level of heat shock proteins (HSPs), which usually increase during traditional photothermal therapy (PTT), especially when the temperature is up 50 °C. 2-deoxy-D-glucose (2DG) is an anti-glycolytic reagent and can be used as an efficient agent for ATP inhibition in tumors. Compared with typical PTT, low-temperature mild photothermal therapy (MPTT) is receiving more and more attention because it avoids the high temperatures causing damage to the normal tissue, and the increase of HSPs which decrease PTT. Here, multifunctional polypeptide nanoparticles pDG@Ahx conjugating both a NIR probe Ahx-BDP and 2DG into the side chain of the amphiphilic polypeptide have been prepared. In vitro and in vivo studies reveal that the as-prepared nanoparticles achieve a synergistic effect of starvation/MPTT/PDT (photodynamic therapy), and it provides a new strategy to NIR-I/II fluorescence imaging-guided starvation/MPTT/PDT synergy therapy for tumors.

In vitro and in vivo evaluation of redox-responsive sorafenib carrier nanomicelles synthesized from poly (acryic acid) -cystamine hydrochloride-D-α-tocopherol succinate

Yu Liu,Jia Yang,Xin Wang,Ju Liu,Zhaobo Wang,Hongsheng Liu,Lijiang Chen

Enhancing the thermal stability of the bulk-heterojunction photovoltaics based on P3HT/PCBM by incorporating diblock amphipathic P3HT–PEO at D/A interface

Jikang Liu,Xiaoguang Zhu,Junli Li,Jiulin Shen,Guoli Tu

A diblock amphipathic copolymer P3HT–PEO was rationally designed and easily synthesized. By introducing P3HT–PEO into P3HT/PCBM blends, the intramolecular interaction between the P3HT–PEO and the donor/acceptor (D/A) molecule in the blends could make the P3HT–PEO located at P3HT/PCBM domains' interface, which could stabilize the morphology of the bulk-heterojunction and also suppress the acceptor PCBM from severe aggregations under prolonged annealing time. By doping only 5 wt% P3HT–PEO, the device-5 (with 5 wt% P3HT–PEO) exhibited a PCE of 3.60% with thermal annealing at 150 °C for 10 min and remained at 3.61% after annealing for 120 min. In contrasted to the device-0 (without P3HT–PEO), the PCE decreased from 3.26% to 1.61% after annealing at 120 min, which also showed lager clusters of PCBM. This finding will inspire new design of additive materials that can control BHJ morphology through to realize highly efficient and thermally stable solar cells.

A comb-like branched β-d-glucan produced by a Cordyceps sinensis fungus and its protective effect against cyclophosphamide-induced immunosuppression in mice

Ting Hu,Chenbo Jiang,Qilin Huang,Fengyuan Sun

An exopolysaccharide (EPS) was fractionated from fermentation media of a Cordyceps sinensis fungus (Cs-HK1) by ethanol precipitation at 2/5 volume ratio of ethanol/media. Its structural characteristics were elucidated by FT-IR, GC, GC–MS, 1D and 2D NMR combined with periodate oxidation, Smith degradation, partial acid hydrolysis, and methylation analysis. Furthermore, the immunomodulatory activity of EPS was evaluated by the model of cyclophosphamide-induced immunosuppression. The results from monosaccharide composition and partial acid hydrolysis indicated that EPS almost consisted of glucose excluding a trace amount of mannose . GC–MS and NMR analysis further confirmed EPS had a linear backbone of (1→3)-β- d -glucopyranosyl residues with a single (1→6)-β- d -glucopyranosyl side-branching unit for every three β- d -glucopyranosyl residues, showing a comb-like β- d -glucan with short and intensive branches, which was responsible for high viscosity. Moreover, EPS could significantly enhance immune organs and stimulate the release of major cytokines TNF-α and INF-γ, suggesting that EPS exhibited protective effect in immunocompromised mice.