查找使用阿拉丁产品的科研文献

An Electrochemical Aptamer-Based (E-AB) Sensor Using Ti3C2Tx(MXene) and cDNA-PAA for Detection of AFB1

Xiaoya Meng,Zhongyu Li,Zili Xia,Dongdong Chen,Zijing Yuan,Yang Han,Heng Zhang,Xia Sun,Jun Seop Lee,Usmanova Surayo Rakhmatzhanovna,Bobokalonov Jamshed Tolehmurodovich,Wenping Zhao

An electrochemical aptasensor based on Ti 3 C 2 T x (MXene) and cDNA-PAA was established for sensitive detection of aflatoxin B1 (AFB1) in peanuts. The high specific surface area of Ti 3 C 2 T x (MXene) contributed to improve electrochemical efficiency and enhancing sensor stability which were characterized by the Randles−Sevcik equation. The self-made polyacrylic acid (PAA) nanogel was added with aptamer complementary chain (cDNA) to form cDNA-PAA nano gel composite, which could realize the synergistic amplification of the difference between the electrochemical signals before and after the addition of AFB1. The sensing effect of cDNA-PAA was validated using DPV. Methylene blue (MB) was modified at the proximal 3′ termini of the aptamer (Apt-MB), meanwhile AuNPs was used to immobilize Apt-MB and improve the efficiency of electrochemical reactions. The competition between AFB1 and cDNA-PAA combined with Apt MB resulted in a significant change in the electrochemical signal current. In addition, the constructed electrochemical aptasensor had a lower detection limit of 1.0 × 10 −3 ng/L for AFB1 under optimal detection conditions, and a detection range of 1 to 1000 ng/L. Moreover, peanuts with different concentrations of AFB1 were used as actual detection samples. Through the constructed sensor detection, the spiked recovery rates within the spiking range of 50 to 500 ng/mL were 97.76% to 101.84% ( n = 3).

Degradation of the neonicotinoid insecticide imidacloprid by ozonation and the E-peroxone process: Mechanisms, transformation products, and toxicity

Yang Zhang,Lingwei Gao,Juhong Zhan,Erzhuo Zhao,Huijiao Wang,Chunrong Wang,Yujue Wang

In this study, degradation of the neonicotinoid insecticide imidacloprid (IMI) by ozonation and the E-peroxone process was investigated. Results show that IMI is an O 3 -refractory compound with second-order rate constants for the reaction with O 3 and • OH ( k O3,IMI and k •OH,IMI ) being 3.9 and 3.95 × 10 9 M −1 s −1 at pH 7, respectively. Due to its low O 3 reactivity, IMI was only abated by < 20 % in a selected groundwater during ozonation with typical ozone doses applied in water treatment (1–5 mg/L). In comparison, the E-peroxone process considerably enhanced IMI removal efficiency to > 80 % under similar reaction conditions. During both ozonation and the E-peroxone process, IMI was mainly abated by • OH oxidation. The reaction mechanism of IMI with • OH was investigated with quantum computations, which show that H-abstraction at H23 site was the most favorable pathway. Sixteen transformation products (TPs) generated from IMI degradation were identified using various chromatographic and mass-spectrometric techniques. The acute and chronic toxicities of IMI and its TPs to different aquatic organisms were evaluated with Microtox bioassay and the ECOSAR program, which indicate that some TPs (e.g., TP 2 –TP 5 and TP 7 –TP 9 ) are even more toxic than IMI to aquatic organisms (e.g., daphnia). The results of this study suggest that IMI along with its TPs should be sufficiently abated during water treatment, and the E-peroxone process provides an efficient option to upgrade conventional ozonation for enhanced IMI abatement.

Flavor diversity characterization of three loquat cultivars via flavoromics combined with E-nose and GC × GC-TOF-MS

Guili Huang,Yu Shi,Xinyao Quan,Qianshuo Shao,Su Yan,Siyao Sui,Jiajia Ma,Jiayu Qian,Weiming Chai,Yuning Wang

Volatile Organic Compounds (VOCs) are critical determinants of loquat flavor quality and cultivar differentiation, but comprehensive characterization and rapid detection remain challenging. This study aimed to establish a robust approach for discriminating three loquat cultivars and evaluating their flavor quality by integrating electronic nose (E-nose) technology and Comprehensive Two-Dimensional Gas Chromatography–Time-of-Flight Mass Spectrometry (GC × GC-TOF-MS). GC × GC-TOF-MS was used for VOC profiling, while E-nose was applied for rapid fragrance characterization, with orthogonal partial least squares-discriminant analysis (OPLS-DA) and correlation analysis performed to identify discriminatory compounds and sensor-VOC relationships. GC × GC-TOF-MS identified over 2000 volatile compounds across three loquat cultivars. OPLS-DA further screened 22 discriminatory VOCs with variable importance in projection (VIP) values >1, which contributed to aroma hierarchy shifts among cultivars. E-nose sensors W1W and W1S showed high sensitivity to floral-scent-related VOCs, serving as key factors for distinguishing fragrance quality. Notably, E-nose detection results exhibited good consistency with GC × GC-TOF-MS data, and W1W/W1S sensors were significantly positively correlated with key VOCs. These findings demonstrate that the integration of E-nose and GC × GC-TOF-MS offers complementary advantages for comprehensive VOC characterization and cultivar discrimination. The established approach provides a scientific basis for optimizing loquat quality standards by incorporating VOC-driven biochemical authenticity and a potential efficient method for rapid, non-destructive assessment of postharvest flavor quality in loquat cultivars. These results facilitate quality control and cultivar authentication in the fruit industry.

Comparative Efficacy of Propyl Gallate, TBHQ, BHT, and Vitamin E in Preserving the Oxidative Stability of Beef Tallow

Ning Zhang,Huihui Zhang,Fengqin Tu,Xinghe Zhang,Jiaojiao Yin,Pan Gao

Beef tallow is valued in the food industry for its unique flavor but remains susceptible to oxidative deterioration during storage and processing, leading to rancidity and quality loss. This study evaluated the effects of four antioxidants (propyl gallate, PG; tert-butylhydroquinone, TBHQ; butylated hydroxytoluene, BHT; and vitamin E, VE) within regulatory limits on beef tallow during 15 days of oven-accelerated oxidation. A multi-index assessment (oxidation indices, antioxidant capacity, tocopherol retention) combined with principal component analysis (PCA) was used. The antioxidants did not alter the fatty acid composition. PCA ranked TBHQ first in overall performance, followed closely by PG. At 0.1 g/kg, PG limited the acid value to 1.49 mg/g and the p-anisidine value to 1.97 after 15 days, although TBHQ at 0.2 g/kg showed a slightly lower acid value (1.28 mg/g). Notably, PG retained 16.06 mg/kg of endogenous tocopherols after 3 days of oxidation, whereas tocopherols were undetectable in TBHQ-treated groups. The FRAP value of the PG group reached 511.95 μmol TE/100 g. Although TBHQ showed strong efficacy, its use has attracted increasing regulatory scrutiny and consumer concern in some regions. PG offers a favorable safety profile while providing comparable protection in several indices, delaying early tocopherol depletion under accelerated oxidation and exhibiting superior FRAP values. Therefore, PG at 0.1 g/kg can serve as a favorable alternative to TBHQ in beef tallow systems.

NAD+ capping of sibD transcripts in E. coli is mediated by its minimal promoter and enhanced by ppGpp

Liu Wuzhen,Hu Kefan,Nie Shiqi,Feng Zhang,Li Qiongfang,Zhang Hailei,Liang Shumin,Peng Jialin,Zhang Shoudong,Cai Zongwei,Xia Yiji

Recently, nicotinamide adenine dinucleotide (NAD+) and other nucleotide analogs have been identified as non-canonical RNA caps in both prokaryotes and eukaryotes. In Escherichia coli, NAD capping has been shown to be influenced by environmental conditions in a gene-specific manner, yet its regulatory mechanisms remain poorly understood. We previously reported that most transcripts produced by sibD are NAD-capped during the stationary phase. In this study, we found that the 35-bp minimal promoter of sibD is sufficient for its NAD capping. When this minimal promoter was applied to express genes not typically producing NAD-RNAs, their transcripts could also be NAD-capped. These findings strongly support that NAD capping in E. coli occurs during transcription initiation mediated by the promoter and RNA polymerase. Additionally, the bacterial alarmone ppGpp and the small protein DksA, both transcription initiation regulators, synergistically enhance transcription of both NAD-capped and uncapped RNAs from sibD and its homologous genes, sibC and sibE, in vitro. In contrast, the ppGpp⁰ mutant, deficient in ppGpp synthesis, showed a significant reduction in NAD-RNA production from these genes. Our findings elucidate the cis-elements and trans-acting factors mediating NAD capping during transcription initiation, offering novel insight into this regulatory process.

Electrochemical detection of E. coli O157:H7 based on NaCl stress improving the bacterial electrocatalytic oxygen reduction performance

Fengyang Wang,Panpan Liu,Yin Chen,Mengjuan Li,Yunlong Liu,Yan Qi,Xiaohui Xiong,Yuanjian Liu

Firstly, through various analytical methods, the mechanism by which the electrocatalytic oxygen reduction capacity of E. coli O157:H7 was enhanced under 4% NaCl stress was revealed. The cyclic voltammetry (CV) results indicated that the oxygen reduction ability of E. coli O157: H7 was improved under NaCl stress. Microbiological analysis confirmed the intracellular ROS levels in E. coli O157: H7 under NaCl stress is related to the upregulation of SOD/CAT activity. Metabolomics identified key metabolic adaptations in E. coli O157:H7, including enhanced tricarboxylic acid (TCA) cycles and ubiquinone (Q) biosynthesis, which promoted effective respiratory electron transfer in the bacteria. Secondly, the BPE-ECL (Bipolar Electrochemiluminescence) sensor designed based on 4% NaCl stress showed 9.72 times increase in anode ECL intensity. The detection limit was extremely low at 10 CFU for E. coli O157:H7 in 1 mL sample volume. This research provides a new solution for the sensitive screening of electrochemically active bacteria.

Efficient biomanufacturing of vitamin E succinate in non-aqueous media via synergistic computational evolution and immobilization of lipase

Zihan Zhang,Yu Zhang,Qingqing Liu,Wanqing Song,Yi Hu,Binbin Nian

A novel triple evolution strategy overcame the lipase activity-stability trade-off. • CM5 showed 2.3-fold higher activity and 4.8-fold solvent tolerance than WT. • MD simulations link CM5 stability to rigidity and stable hydration shell. • The VES synthesis strategy achieved the highest yield and reusability to date. • A complete chain from computational design to practical production was validated. Biocatalysts exhibit broad application prospects in industrial production. However, the inherent instability of natural enzymes in non-aqueous media severely limits their practical utilization. Using Candida rugosa lipase as a model, a synergistic evolution strategy integrating ancestral sequence reconstruction, free energy optimization and surface hydration shell modulation was developed in this study. The optimal mutant CM5 exhibited simultaneously enhanced stability and activity, showing a 4.78-fold increase in tolerance to 65% (v/v) dimethyl sulfoxide, a 1.67-fold extension in half-life at 50 ℃ and a 2.30-fold increase in activity compared to the wild type. Molecular dynamics simulations indicated that the enhanced stability of CM5 originates from improved structural rigidity and the stabilized hydration shell. Meanwhile, its increased activity is attributed to a reduced energy barrier for the lid conformational transition and an optimal enzyme substrate affinity that significantly boosts substrate turnover efficiency. Moreover, a volumetric activity of 142.71 U/mL in a 5 L bioreactor was obtained via optimization of the chassis cells, and the resulting culture was then used for the immobilization. The lipase CM5 immobilized on amino octadecyl bifunctional macroporous resin (CM5@AOMR) achieved a vitamin E succinate yield of > 99.9% and maintained an outstanding yield of 98.2% even after ten consecutive batch reactions. Overall, this study developed a comprehensive workflow from computational design and efficient fermentation to immobilization and practical applications of lipase, providing a promising new approach for developing next generation biocatalysts suited for extreme industrial environments. Download: Download high-res image (234KB) Download: Download full-size image

Highly stable thiourea-functionalized polyhedral oligomeric Silsesquioxane adsorbent for efficient and selective gold recovery from E-waste leachate

Qian Du,Qingshan Li,Hao Li,Jianming Pan

With the fast pace of technological advancement and the accelerating replacement cycle of electronic devices, the process of extracting gold from electronic waste ( E -waste) has emerged as a pivotal challenge for resource recycling and environmental sustainability. In this work, a series of thiourea-functionalized polyhedral oligomeric silsesquioxane (POSS)-based polymers (POSS@ATU-X) abundant in sulfur (S) and nitrogen (N) active sites was synthesized through a facile one-step functionalization strategy, and its performance and underlying mechanism for Au(III) adsorption were systematically investigated. POSS@ATU-4 delivered a rapid adsorption kinetic profile, with 90% of its maximum adsorption capacity attained within 3 h and equilibrium reached at 6 h. Isothermal adsorption tests revealed an ultra-high maximum adsorption capacity of 2643.64 mg g −1 at 318 K. Notably, POSS@ATU-4 exhibited outstanding selectivity for Au(III) in both multi-metal coexisting systems and actual printed circuit board (PCB) leachate, with its removal rate far exceeding those of other coexisting metal ions. After six consecutive adsorption-desorption cycles, the material retained 99% of its initial adsorption efficiency, demonstrating exceptional structural stability and reusability. Mechanistic studies elucidated that Au(III) removal was governed by the synergistic effects of electrostatic attraction and surface coordination interactions. This work provides a feasible and effective strategy for achieving highly selective and stable gold recovery from acidic E -waste streams, which holds great promise for practical industrial applications.

Inhibitory effect of (E)-2-hexenal as a potential natural fumigant on Aspergillus flavus in stored peanut seeds

Weibin Ma,Luling Zhao,Yanli Xie

The efficacy of eight kinds of green leaf volatiles (GLVs) was investigated as potential natural antifungal agents against Aspergillus flavus in this study. Based on the in vitro assay, volatile phase inhibitory effects of the selected eight GLVs were consistently more effective on A. flavus growth than contact phase inhibitory effects, and ( E )-2-hexenal exhibited the highest efficacy as it could totally inhibited growth of A. flavus at concentrations of 0.032   μL/mL air and 1.6   μL/mL under vapor and contact conditions, respectively. Furthermore, results obtained from the in vivo assay demonstrated that ( E )-2-hexenal possessed potent fumigant activity in reducing A. flavus infection in stored peanut seeds, as it could completely inhibit colonization of A. flavus at 0.32   μL/mL air. Both in vitro and in vivo assay results provided convincing evidence that ( E )-2-hexenal, one of the GLVs that is naturally present in many plants, can potentially be used as a highly efficient and eco-friendly antifungal fumigant to protect peanut seeds from contamination of A. flavus during storage.

Orientin inhibits cyclin E/cyclin A-CDK2 to induce growth arrest at senescence in human gastric cancer cells

Yang Yan,Yongfei Gu

Gastric cancer (GC) is a primary epithelial malignancy originating in the stomach. This research explored the influence and mechanism of Orientin on cellular senescence in GC. Orientin was predicted to regulate multiple cell cycle-related pathways, including cyclin-dependent protein kinase activity. Orientin docked with cyclin dependent kinase 2 (CDK2), cyclin A2 (CCNA2), cyclin E1 (CCNE1), and cyclin E2 (CCNE2) with binding energies of -9.1, -7.5, -7.2, and -8.3 kcal/mol, respectively. The IC 50 values of Orientin for AGS and HGC-27 cells were 24.33 μM and 39.28 μM, respectively. Orientin dose-dependently inhibited GC cell proliferation, promoted G0/G1 phase arrest, as well as downregulated CDK2, CCNA2, CCNE1, and CCNE2 expression. It enhanced senescence-associated β-galactosidase staining intensity, upregulated p16 and p21, and downregulated phosphorylated retinoblastoma (p-Rb). In vivo , Orientin also suppressed tumor progression, promoted p16 and p21 expression, and inhibited CCNE/CCNA-CDK2 signaling. Orientin exerts anti-cancer effects in GC through triggering cellular senescence and cell cycle arrest, likely via activating p16/p21-Rb signaling axis and inhibiting the CCNE/CCNA-CDK2 pathway. Download: Download high-res image (282KB) Download: Download full-size image

Design, Synthesis, and Insecticidal Activity of the Derivatives of Taiwanin E, an Insecticidal Lignan from Taiwania flousiana Gaussen

Feng Hao,Chenzhe Li,Yan Luo,Tingcai Dong,Chengyao Wang,Ziruo He,Jiting Li,Huaizhang Yang,Kun Wei,Yabin Yang,Le Cai

Rising environmental and health risks of synthetic pesticides have fueled the search for eco-friendly alternatives. Taiwania flousiana Gaussen, a rare evergreen, is a valuable source of bioactive compounds, with the lignan Taiwanin E (from its discarded bark in Yunnan, China) showing potential insecticidal activity. Herein, we chemically modified Taiwanin E to improve its solubility and insecticidal activity, and the resultant derivative E13 exhibited potent larvicidal activity against Armigeres subalbatus larvae. Enzyme assays, molecular docking, and dynamics simulations validated this activity, while DFT calculations clarified the structural basis for E13’s superior performance. Bee toxicity tests further confirmed its environmental safety. This study identifies Taiwanin E derivatives as promising sustainable alternatives to conventional insecticides, advancing eco-friendly pest control and enabling resource utilization of the endangered T. flousiana.

Paclitaxel-loaded redox-sensitive nanoparticles based on hyaluronic acid-vitamin E succinate conjugates for improved lung cancer treatment

Yu Song,Han Cai,Tingjie Yin,Meirong Huo,Ping Ma,Jianping Zhou,Wenfang Lai