查找使用阿拉丁产品的科研文献

A CQDs-doped europium-DPA framework for fluorescence and colorimetric dual-mode sensing of amoxicillin and ciprofloxacin

Yi Jintao,Fu Nani,Zhong Wenhui,Liu Xia,Zhou Anqi,Li Xun

Amoxicillin (AMO), a penicillin antibiotic, and ciprofloxacin (CIP), a quinolone antibiotic, are widely used to combat bacterial infections and are frequently co-administered to enhance therapeutic efficacy. However, improper use of AMO and CIP may lead to antibiotic residues in the environment, posing serious threats to human health. The visual detection of AMO and CIP remains significant challenges. Herein, the Eu-DPA@CQDs was used for the dual-mode detection of AMO and CIP, which was synthesized by CQDs doped in europium-DPA metal-organic framework. In the colorimetric mode, the catalase-mimicking Eu-DPA@CQDs oxidized TMB to blue oxTMB. Upon addition of AMO, the oxTMB was reduced, causing color fading. Subsequent introduction of CIP restored nanozyme activity, regenerating the blue signal and enabling dual-analyte antibiotic detection. In the fluorescence mode, the Eu-DPA@CQDs probe exhibited dual emission at 440 nm and 613 nm. Upon AMO addition, the fluorescence at both wavelengths was quenched, accompanied by a color change from red to purple. In the presence of CIP, the emission at 440 nm increased and redshifted to 490 nm, while the signal at 613 nm was quenched, resulting in a multicolor transition from red to cyan. The Eu-DPA@CQDs sensor enabled rapid and dual-mode detection of AMO and CIP. The colorimetric method exhibited wide linear ranges of 0.005–25 μM for AMO and 0.007–4.25 μM for CIP, with detection limits of 1.67 nM and 3.75 nM, respectively. A visible color transition from dark blue to colorless was observed with increasing AMO concentration, while the addition of CIP reversed the signal back to dark blue. Similarly, the fluorescence detection achieved wide linear ranges from 0.005 to 30 μM for AMO and 0.005 to 15 μM for CIP, with detection limits as low as 4.74 nM and 3.11 nM, respectively, also within only 1 min. As the concentration of AMO increased, the color shifted from red to purple. In contrast, increasing CIP concentration induced a color transition from red to cyan. These color transitions were both clearly visible to the naked eye. The sensor demonstrated excellent selectivity and anti-interference capability, providing a reliable platform for accurate, sensitive, and quantitative determination of both antibiotics in real samples. Graphical abstract

A highly sensitive electrochemical sensor derived from peptide amphiphilic inspired self-assembled, ordered gold nanoparticles for determination of 22 β-lactams

Yexuan Mao,Yichao Fan,Ran Yang,Youyi Wang,Qingyue Li,Meng Dang,Xianqing Huang,Lianjun Song,Pingan Zhang,Miao Song,Liang Liu,Linli Wang,Shun Yu,Qiuyan Zhao,Xiya Zhang

Achieving ordered arrangement of gold nanoparticles (AuNPs) on an electrode can further improve the signal intensity of an electrochemical immunosensor. This ordered AuNPs self-assembly can be inspired by peptide amphiphile (PA). The rational design of hydrophobic chains in PA is a crucial step when the range of hydrophobic alkane chain from 14 to 18 carbons. As arginine (R) can combine specifically with Au surface plane (111), four PAs, i.e., C 15 H 23 CO-RR (C16R2), C 15 H 23 CO-RRR (C16R3), C 15 H 23 CO-RRRR (C16R4), and C 15 H 23 CO-RRRRR (C16R5), in this work are designed to investigate the extent of ordered AuNPs self-assembly. The results indicate that C16R4 presented a dominant electron donating ability and can inspire the self-assembly of AuNPs to form a mono-dispersed raspberry-like structure (C16R4-AuNPs) to obtain the largest ΔI (15.4 μA). In the detection system, C16R4-AuNPs firstly capture and immobilize anti-β-lactam receptor monoclonal antibodies (mAb) by electrostatic adsorption, and the anti-β-lactam receptor mAb possess antigen-antibody binding sites away from the active site of the receptors. Then, they capture β-lactam receptors through an antigen-antibody reaction to form a ternary complex (C16R4-AuNPs-mAb-β-lactam receptors). Based on this indirect-labeling process, the receptor active sites have been exposed completely, facilitating ligand recognition, which greatly further improves the sensitivity of the present method. Finally, a highly sensitive electrochemical immunosensor based on the ternary complex is developed to achieve the determination of 22 β-lactam antibiotics, which is more sensitive and applicable than other reported electrochemical sensors.

Rapid Determination of Cephalexin in Animal-Derived Food by an Indirect Competitive Enzyme-Linked Immunosorbent Assay

Shuangmin Wu,Wei Shen,Yushuang Chen,Yongli Zhu,Ren Hou,Menghong Dai,Dapeng Peng

Synthesis and Properties of Cefixime Core–Shell Magnetic Nano-Molecularly Imprinted Materials

Li Zhang,Hongbo Mo,Chuan Wang,Xiaofeng Li,Shuai Jiang,Weigang Fan,Yagang Zhang

Novel core–shell magnetic molecularly imprinted polymers (MMIPs) were synthesized using the sol–gel method for the adsorption of cefixime (CFX). Fe3O4@SiO2is the core, and molecularly imprinted polymers (MIPs) are the shell, which can selectively interact with CFX. The preparation conditions, adsorption kinetics, adsorption isotherms, selective adsorption ability, and reutilization performance of the MMIPs were investigated. The adsorption capacity of MMIPs for CFX was 111.38 mg/g, which was about 3.5 times that of MNIPs. The adsorption equilibrium time was 180 min. The dynamic adsorption experiments showed that the adsorption process of MMIPs to CFX conformed to the pseudo-second-order model. Through static adsorption study, the Scatchard analysis showed that MMIPs had two types of binding sites—the high-affinity binding sites and the low-affinity binding sites—while the Langmuir model fit the adsorption isotherms well (R2= 0.9962). Cefepime and ceftiofur were selected as the structural analogs of CFX for selective adsorption studies; the adsorption of CFX by MMIPs was higher than that of other structural analogs; and the imprinting factors of CFX, cefepime, and ceftiofur were 3.5, 1.7, and 1.4, respectively. Furthermore, the MMIPs also showed excellent reusable performance.

Emergence and mobilization of a novel lincosamide resistance gene lnu(I): From environmental reservoirs to pathogenic bacteria

Zhishuang Yang,Tianjing Lan,Hongyan Luo,Pei Li,Mingshu Wang,Renyong Jia,Shun Chen,Mafeng Liu,Xinxin Zhao,Qiao Yang,Ying Wu,Shaqiu Zhang,Juan Huang,Xumin Ou,Sai Mao,Qun Gao,Di Sun,Bin Tian,Anchun Cheng,Dekang Zhu

Antimicrobial resistance remains an utmost concern in human and veterinary medicine, impacting humans, animals, and the environment while significantly influencing the principles of One Health. While Riemerella anatipestifer ( R. anatipestifer ) is recognized as a waterfowl pathogen with multidrug-resistant properties, the specifics of its lincosamide resistance mechanism are inadequately understood. In this study, we identified a novel lincosamide resistance gene, lnu (I), in R. anatipestifer RCAD0121, and investigated its potential origin, transfer mechanisms, and dissemination status through genomic epidemiology. This exhibited 74.80 % amino acid identity with a previously reported gene, lnu (H). PCR analysis revealed lnu (I) prevalence in at least 44 R. anatipestifer isolates collected from multiple provinces in China. Furthermore, genomic mining unveiled 56 lnu (I) sequences within publicly available databases, primarily originating from environmental sources. In addition, members of the family Flavobacteriaceae were the dominant (16/56, 28.57 %) bacteria carrying the lnu (I) gene, with Flavobacterium exhibiting a similar GC content as lnu (I). Notably, specific instances of the lnu (I) gene were linked to mobile genetic elements within human and animal pathogenic bacteria. These findings suggest that Flavobacterium species within the environment could serve as potential ancestral sources of the novel lnu (I) gene, which has undergone mobilization events toward pathogenic bacteria.

Recognition and binding of FEZ-1 from Legionella with penicillin V and cefoxitin by fluorescence spectra in combination with molecular dynamics simulation

Xiaoting Dong,Pengli Xue,Xian Ma,Yifan Bai,Penghui Shi,Liujiao Bian

The recognition and interaction of FEZ-1 from Legionella (FEZ-1) with penicillin V(PV) and cefoxitin(CFX) were investigated using fluorescence spectra in combination with molecular dynamics simulation (MD). The results revealed that the CFX bind with FEZ-1 in stronger interaction and induced larger conformational change than PV, despite all being forced by the electrostatic interaction and along with the changing in an environment of amino acid residues as well as the polypeptide skeleton inside the FEZ-1. Moreover, only the loop1, loop2, and N-terminal were observed locating near the binding pocket of FEZ-1, consisting of a flexible “gate-like” zone with better adaptability that controlled the entrance of antibiotic into the pocket by allowing the newly introduced antibiotic to match the pocket better through the conformational changes of these three substructures in the binding procedure. The current study may provide some valuable information on the antibiotic hydrolytic process by metallo-beta-lactamase and thus the references for the development of new antibiotics for super bacteria.

Ceftizoxime loaded ZnO/l-cysteine based an advanced nanocarrier drug for growth inhibition of Salmonella typhimurium

Bacchu M. S.,Ali M. R.,Setu M. A. A.,Akter S.,Khan M. Z. H.

l -Cysteine coated zinc oxide (ZnO) nano hollow spheres were prepared as a potent drug delivery agent to eradicate Salmonella enterica serovar Typhimurium ( S. typhimurium ). The ZnO nano hollow spheres were synthesized by following the environmentally-friendly trisodium citrate assisted method and l -cysteine (L-Cys) conjugate with its surface. ZnO/L-Cys@CFX nanocarrier drug has been fabricated by incorporating ceftizoxime with L-Cys coated ZnO nano hollow spheres and characterized using different techniques such as scanning electron microscope (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR), and X-ray diffraction (XRD) etc. Furthermore, the drug-loading and encapsulation efficiency at different pH levels was measured using UV–vis spectrometer and optimized. A control and gradual manner of pH-sensitive release profile was found after investigating the release profile of CFX from the carrier drug. The antibacterial activity of ZnO/L-Cys@CFX and CFX were evaluated through the agar disc diffusion method and the broth dilution method, which indicate the antibacterial properties of antibiotics enhance after conjugating. Surprisingly, the ZnO/L-Cys@CFX exhibits a minimum inhibitory concentration (MIC) of 5 µg/ml against S. typhimurium is lower than CFX (20 µg/ml) itself. These results indicate the nanocarrier can reduce the amount of CFX dosed to eradicate S. typhimurium .

A Cd-MOF as a fluorescent probe for highly selective, sensitive and stable detection of antibiotics in water

Pengcheng Xing,Di Wu,Jingshuai Chen,Jiming Song,Changjie Mao,Yuanhao Gao,Helin Niu

Recently, the pollution and damage caused by antibiotics in water have aroused serious concerns. In this situation, it is extremely important to develop a highly effective approach to detect antibiotics in water. In this contribution, we built a Cd-MOF material with stable fluorescence properties, using bbi = 1,4-bis(2-methyl-imidazol-1-yl)butane and H2L = 1,2-phenylenediacetic acid as organic ligands and Cd(NO3)2·4H2O as the metal node. The highly selective response of this MOF probe to ceftriaxone sodium (an antibiotic) can reach up to the ppb level in water, along with a fast response time, acid and alkali resistance, and anti-interference ability.

A novel resistance gene, lnu(H), conferring resistance to lincosamides in Riemerella anatipestifer CH-2

Hong-Yan Luo,Ma-Feng Liu,Ming-Shu Wang,Xin-Xin Zhao,Ren-Yong Jia,Shun Chen,Kun-Feng Sun,Qiao Yang,Ying Wu,Xiao-Yue Chen,Francis Biville,Yuan-Feng Zou,Bo Jing,An-Chun Cheng,De-Kang Zhu

The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 128 µg/mL. The G148_1775 gene of R. anatipestifer CH-2, designated lnu (H), encodes a 260-amino acid protein with ≤41% identity to other reported lincosamide nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24- lnu (H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu (H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu (H) gene. The transformant R. anatipestifer ATCC 11845 [ lnu (H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu (H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2.

Fabrication and evaluation of stationary phases with different morphology from two imidazole-based ligands for nonchiral and chiral electrochromatographic separation

Mo Chen,Yuanyuan Hou,Xinyu Liang,Fuquan Zhao,Liming Bai,Hongtao Chu,Shili Qin,Ming Zhao,Lidi Gao,Shuren Liu

In this work, two metal-organic porous materials from the two imidazole-based ligands (4-methylimidazole-5-carbaldehyde (aImeIm) and histidine (His)) and the same metal source (Zn(CH 3 COO) 2 ·2H 2 O), namely His-ZIF-93 with a crystal zeolite imidazolate framework and His/aImeIm@Zn with an amorphous networks, were first designed and synthesized by the one-pot method. They were used as the stationary phases (SPs) of open-tubular capillary electrochromatography (OT-CEC) to evaluate and compare their separation performance for the nonchiral and chiral compounds. His-ZIF-93-bonded OT-CEC column successfully separated five families of nonchiral analytes due to the synergistic effect of His and the crystal framework. The separation mechanism included electrostatic interaction, molecular sieve effect, π-π interaction, electrophoretic mobility, hydrogen bonding interaction, and so on. His/aImeIm@Zn-bonded OT-CEC column exhibited a more superior enantioseparation capability for seven chiral compounds with an ultrahigh column efficiency of 7.6 × 10 5 plates/m due to a large number of chiral sites and the porous networks. Enantioseparation were attributed to the difference of adsorption and selectivity between the SPs and the two enantiomers through the adsorption experiments and the binding constants tests. Thus, both His-ZIF-93-bonded OT-CEC column and His/aImeIm@Zn-bonded OT-CEC column demonstrated the universality for the analytes, as well as excellent reproducibility, satisfactory stability and long lifetime.

Mn-doped ZnS quantum dots@dendritic mesoporous silica phosphorescent nanocomposites for antimicrobial susceptibility testing

Shiqing Luo,Xiaojie Sun,Lifang Zhang,Yanming Miao,Guiqin Yan

The excessive use of antibiotics has accelerated the rise of antimicrobial resistance (AMR), and rapid antimicrobial susceptibility testing (AST) is very important for the early detection, early prevention and treatment of AMR. On this basis, we combined manganese-doped zinc sulfide quantum dots (Mn-ZnS QDs) with aminated dendritic mesoporous silica nanoparticles (DMSNs-NH 2 ) to prepare Mn-ZnS QDs@DMSNs-NH 2 room-temperature phosphorescent (RTP) nanocomposites. H 2 O 2 can quench the RTP of Mn-ZnS QDs@DMSNs-NH 2 nanocomposites, while catalase-positive bacteria can cause the hydrolysis of H 2 O 2 . Hence, RTP detection of different antibiotic tolerance for Staphylococcus aureus ( S. aureus ) and methicillin-resistant Staphylococcus aureus (MRSA) was achieved. This sensing system can achieve rapid bacterial detection and AST through the difference in RTP intensity. Experimental results demonstrated that the linear detection range for bacteria is 0×10 5 -64×10 5 CFU·mL -1 , with a limit of detection (LOD) of 1×10 5 CFU·mL -1 for MRSA and 0.7×10 5 CFU·mL -1 for S. aureus . The pore confinement effect of DMSNs-NH 2 can induce the aggregation of Mn-ZnS QDs, which strengthens the RTP of Mn-ZnS QDs@DMSNs-NH 2 nanocomposites and improves the sensitivity of RTP detection. This method is not only free from sample background fluorescence interference, but also shortens the AST time (less than 90   min), making antibacterial treatment more time-saving and efficient and reducing patient pains. This nanosensor provides a new strategy for rapid clinical bacterial detection and effective assessment of antimicrobial susceptibility.

Novel inhibition of Staphylococcus aureus sortase A by plantamajoside: implications for controlling multidrug-resistant infections

Yujia Chen,Wei Li,Li Wang,Bingmei Wang,Jian Suo

In confronting the significant challenge posed by multidrug-resistant (MDR) pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA), the development of innovative anti-infective strategies is essential. Our research focuses on sortase A (SrtA), a vital enzyme for anchoring surface proteins in S. aureus. We discovered that plantamajoside (PMS), a phenylpropanoid glycoside extracted from Plantago asiatica L. (Plantaginaceae), acts as an effective and reversible inhibitor of SrtA, with a notable IC50 value of 22.93 µg/mL. This breakthrough provides a novel approach to combat both resistance and virulence in MRSA. PMS significantly inhibits S. aureus adhesion to fibrinogen, reducing biofilm formation and hindering the anchoring of staphylococcal protein A to the cell wall. Live-dead cell assays demonstrated increased survival rates in PMS-treated MRSA-infected A549 cells. Fluorescence quenching experiments revealed a robust interaction between PMS and SrtA, with mechanistic analyses pinpointing the critical R197 amino acid residue as the target site. In vivo, PMS was highly effective in a Galleria mellonella infection model, reducing mortality rates in MRSA-infected larvae. Additionally, PMS demonstrated therapeutic efficacy in a mouse pneumonia model, improved survival rates, reduced the bacterial load in pulmonary tissues, and mitigated lung damage. These results validate PMS as a promising compound to mitigate MRSA virulence and thwart resistance by targeting SrtA. This study highlights PMS as a leading candidate for controlling MRSA infections, showing the potential of targeting specific bacterial mechanisms in the fight against MDR infections.