CHEMOSPHERE
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2017
·
IF 4.208
Can-Hui Deng,Ji-Lai Gong,Guang-Ming Zeng,Peng Zhang,Biao Song,Xue-Gang Zhang,Hong-Yu Liu,Shuang-Yan Huan
Nanotechnology has great potential in water purification . However, the limitations such as aggregation and toxicity of nanomaterials have blocked their practical application. In this work, a novel copper nanoparticles-decorated graphene sponge (Cu-GS) was synthesized using a facile hydrothermal method. Cu-GS consisting of three-dimensional (3D) porous graphene network and well-dispersed Cu nanoparticles exhibited high antibacterial efficiency against Esherichia coli when used as a bactericidal filter. The morphological changes determined by scanning electron microscope and fluorescence images measured by flow cytometry confirmed the involvement of membrane damage induced by Cu-GS in their antibacterial process. The oxidative ability of Cu-GS and intercellular reactive oxygen species (ROS) were also determined to elucidate the possible antibacterial mechanism of Cu-GS. Moreover, the concentration of released copper ions from Cu-GS was far below the drinking water standard, and the copper ions also have an effect on the antibacterial activity of Cu-GS. Results suggested that Cu-GS as a novel bactericidal filter possessed a potential application of water disinfection .
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MOLECULES
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2017
·Vol. 22
·期 3
·432
·
IF 2.861
Rensen Ran,Huan Zeng,Dong Zhao,Ruiyuan Liu,Xia Xu
Microcin C7 (McC), widely distributed in enterobacteria, is a promising antibiotic against antibiotic resistance. Previous studies have demonstrated that the heptapeptide of McC is only responsible for recognizing the inner membrane transporterYejABEFto deliver McC into microbial cells, but lacks the capacity for inhibiting microbial cell growth. In this study, the effect of the heptapeptide (MR) and two analogues,N-formylated heptapeptide (f-MR) andN-aceylated heptapeptide (a-MR), on microbial cell growth were examined. It is surprising to find that MR not only inhibits the activity of intracellular β-galactosidase, respiratory chain dehydrogenases, and 6-phosphogluconate dehydrogenases (6PGDH), but it is also able to inhibitEscherichia coligrowth, and eventually leads to cell death at the lethal concentration of 5.34 mM within 10 min. The modification of MR results in a slight increase in the lethal concentration. Cell membrane integrity at the lethal concentration confirms that MR undergoes the inhibition effect, but not by destroying the cell membrane integrity. The novel property of MR provides a new insight into the Trojan horse strategy of McC and opens a new route for antibiotics design.Keywords:microcin C7;heptapeptide;cell growth;membrane integrity
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Biotechnology for Biofuels and Bioproducts
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2025
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IF 4.6
Kai Wang,Xuewei Pan,Taowei Yang,Zhiming Rao
To address the challenge of microbial tolerance in industrial biomanufacturing, we developed an adaptive evolution strategy for Escherichia coli W3110 to enhance its salicylic acid (SA) tolerance. Utilizing a CmeR-P cmeO biosensor-enabled high-throughput screening system, we isolated an SA-tolerant variant (W3110K-4) that exhibited a 2.3-fold increase in tolerance (from 0.9 to 2.1 g/L) and a 2.1-fold improvement in SA production (from 283 to 588.1 mg/L). Subsequently, the designed sensors were combined with multi-pathway sgRNA arrays to dynamically modulate the other three branched-chain acid derivatives, achieving a balance between biomass growth and rapid SA production in the adaptively evolved strain, resulting in a maximum SA yield of 1477.8 mg/L, which represents a 30% improvement over the non-evolved control strain W3110K-W2 (1138.2 mg/L) using the same metabolic strategy. Whole-genome sequencing revealed that adaptive mutations in genes such as ducA * and anti-drug resistance C2 mutation genes ( ymdA *, ymdB *, clsC *, csgB *, csgA *, and csgC *) play a key role in enhancing SA tolerance and productivity. Notably, the evolved strain W3110K-4 exhibits significant resistance to bacteriophages, making it a promising candidate for large-scale SA fermentation. This work develops and expands the CmeR-P cmeO system, proposes new insights into improved strains through biosensor screening, guided multi-pathway metabolism, and adaptive evolution, and provides a paradigm for engineers to obtain engineered strains.
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MICROCHEMICAL JOURNAL
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2024
·
IF 4.9
Li Fu,Fangzhou Lv,Kaixin Liu,Ruobo Chen,Hongxuan Zhang,Huihui Su,Yi Fan,Li Jia
The cost-effective and label-free fluorescent sensor, which leverages a combination of glutathione-stabilized copper nanoclusters (GSH-CuNCs) and readily available copper ions (Cu 2+ ), presents a highly effective strategy for the selective and sensitive detection of Escherichia coli ( E. coli ) and Salmonella typhimurium ( S. typhimurium ). The sensor operates on the principle of aggregation-induced emission enhancement (AIEE), where the fluorescence of GSH-CuNCs is enhanced upon interaction with Cu 2+ . This enhancement is further modulated by the reduction of Cu 2+ by E. coli and S. typhimurium through a copper-homeostasis mechanism, allowing for the detection of these bacteria. The sensor demonstrates a linear response to E. coli and S. typhimurium over a concentration range of 10 3 to 10 7 cfu mL −1 . The detection limits for these bacteria are determined to be 111 cfu mL −1 for E. coli and 130 cfu mL −1 for S. typhimurium , respectively. The practical utility of the sensor has been confirmed through its successful application in detecting these bacterial strains in complex samples such as eggshell and popsicle matrices, showcasing its potential for real-world food safety monitoring.
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ULTRASONICS SONOCHEMISTRY
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2024
·
IF 8.7
Jinyue Sun,Qian-Jun Shen,Jia-Neng Pan,Xiaodong Zheng,Ting Yu,Wen-Wen Zhou
The purpose of this study was to investigate ferroptosis in Escherichia coli O157:H7 caused by ferrous sulfate (FeSO 4 ) and to examine the synergistic effectiveness of FeSO 4 combined with ultrasound-emulsified cinnamaldehyde nanoemulsion (CALNO) on inactivation of E. coli O157:H7 in vitro and in vivo . The results showed that FeSO 4 could cause ferroptosis in E. coli O157:H7 via generating reactive oxygen species (ROS) and exacerbating lipid peroxidation. In addition, the results indicated that FeSO 4 combined with CALNO had synergistic bactericidal effect against E. coli O157:H7 and the combined treatment could lead considerable nucleic acids and protein to release by damaging the cell membrane of E. coli O157:H7. Besides, FeSO 4 combined with CALNO had a strong antibiofilm ability to inhibit E. coli O157:H7 biofilm formation by reducing the expression of genes related on biofilm formation. Finally, FeSO 4 combined with CALNO exhibited the significant antibacterial activity against E. coli O157:H7 in hami melon and cherry tomato.
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Frontiers in Veterinary Science
·
2025
·
IF 2.9
Qiuru Chen,Yulei Liang,Yanbin Dong,Junling Cui,Kun He,Xiaoyuan Ma,Jinfeng Zhao,Yajun Zhai,Li Yuan
H-NS is a histone-like nucleoid-structuring protein that regulates gene expressions, particularly acquired foreign genes, however, little is known about whether H-NS can modulate bacterial susceptibility by regulating its intrinsic genes. The hns-deleted mutant EΔhns, the hns-complemented strain EΔhns/phns and the hns-overexpressed strain E/phns were derivatives of Escherichia coli ATCC 25922, the susceptibility of which were assessed by the broth microdilution method and time-kill curves assays. We found that the MICs for strain EΔhns against gentamicin and amikacin were significantly decreased by 8–16 folds in contrast to E. coli ATCC 25922. Further studies displayed that the absence of hns caused damage to the bacterial outer membrane and increased the expression levels of porin-related genes, such as ompC, ompF, ompG, and ompN, thus obviously enhancing aminoglycosides uptake of strain EΔhns. Meanwhile, hns deletion also led to remarkable inhibition of the efflux pumps activity and decreased expressions of efflux-related genes clbM, acrA, acrB, acrD, and emrE, which reduced the efflux of aminoglycosides. In addition, the activation of glycolysis and electron transport chain, as well as the reduction of Δψ dissipation, could lead to a remarkable increase in proton motive force (PMF), thus further inducing more aminoglycosides uptake by strain EΔhns. Our findings reveal that H-NS regulates the resistance of E. coli to aminoglycosides by influencing its uptake and efflux, which will enrich our understanding of the mechanism by which H-NS modulates bacterial resistance.
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Molecular Catalysis
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2024
·
IF 3.9
Jiaxin Li,Yi Guo,Jienan Li,Hua Zhang,Li Wang,Changhai Liang
5-cyanopentanamide (5-CVAM) is an important intermediate for fine chemicals and pesticides. Previously, our group found a novel nitrile hydratase (ReNhase) that can convert adiponitrile (ADN) into 5-CVAM. Nevertheless, the poor tolerance of recombinant Escherichia coli (E. coli) strain has caused limitations in industrial applications. Herein, the tolerance of recombinant E. coli cells expressing ReNhase was explored by combining the IrrE gene, which is a representative global regulator derived from Deinococcus radiodurans . Results show that the tolerance of the modified strains was improved significantly with organic solvent. ReNhase TAC strain and ReNhase AmpRp strain were 2.8 times and 2.3 times higher than that of ReNhase WT strain in the yield of 5-CVAM. Meanwhile, the modified strains have outstanding performance in acid-base tolerance, thermal stability and tolerance in high salt solution. It is also found that the modified strains had smaller changes in mitochondrial membrane potential under the pressure environments described above. In terms of cell surface hydrophobicity, the modified strains had lower adsorption rates for organic solvents, which further confirmed the excellent tolerance of modified strains. The findings will provide a new theoretical basis for the modification of recombinant E. coli for improving the catalytic efficiency of adiponitrile in industrial production.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2025
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IF 6.2
Ling Ma,Zhichao Chen,Xu Li,Weiwei Liu,Zichen Yu,Changgeng Li,Yu Gong,Qingyang Xu
Metabolic regulation and fermentation strategies limit the synthesis of tyramine. Here, a de novo synthetic tyramine-producing strain, LAN 25, was constructed. First, tyramine-producing strain was obtained by modifying the key metabolic nodes of tyrosine synthesis and overexpressing the tyrosine decarboxylase gene from Lactobacillus brevis. Then, a two-stage dissolved oxygen (DO)-controlled fermentation process was established in a 5 L fed-batch bioreactor. In the first stage, sufficient DO was supplied to accumulate tyrosine precursors, while in the second stage, limited DO was provided to promote tyramine synthesis. Next, ldhA and adhE were deleted to improve the strain’s robustness. To enhance the redox flux (ATP/ADP ratio) under limited DO conditions, the anaerobic promoter, Pvgb, was used to control the expression of a ppk-based ATP regeneration system in response to DO changes. Additionally, the tyrosine internal transport system was modified. Finally, a titer of 21.33 g/L of tyramine with a yield of 0.092 g/g glucose was obtained.
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ANALYST
·
2024
·
IF 3.6
Xiaoqing Zhang,Shanglin Li,Mei Liu
Bacterial contamination is a serious issue for public health and food safety. In this work, a simple and label-free fluorescence detection nanoplatform for Escherichia coli (E. coli) was established on the basis of the competitive relationship for the reduction of Cu2+ in CuS-BSA between E. coli and O-phenylenediamine (OPD). OPD could be directly oxidized by Cu2+ to produce 2,3-diaminophenazine (ox OPD) with fluorescence properties. When OPD was introduced into an aqueous solution containing CuS-BSA and E. coli, the oxidation of OPD was inhibited owing to the reduction of Cu2+ to Cu+/Cu0 by NADH-2 dehydrogenase in the bacterial copper homeostasis mechanism, thus decreasing the fluorescence response signal of the system. Meanwhile, our strategy exhibited a satisfactory performance with a broad linear response to E. coli ranging from 12 to 1.2 × 107 CFU mL−1, and the limit of detection was 9 CFU mL−1. The practicability of the developed fluorescence biosensing platform in real samples was evaluated by successful determination of E. coli in drinking water and orange juice. These findings provide a new sensing strategy for analyzing other foodborne bacteria and ensuring food safety assessment.
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Arabian Journal of Chemistry
·
2024
·
IF 5.3
Ping Cheng,Botao Wang,Shuying Liang,Yuqi Yang,Shixin Gui,Kai Zhang,Yingying Sun,Shaoqi Qu,Lin Li
Colistin used to be regarded as the last-resort treatment for the infection caused by multidrug-resistant gram-negative bacteria. However, the emergence and widespread of mcr-1 seriously reduce the clinical effectiveness of colistin, constituting a serious threat to global public health. Due to the difficulties in the development of new antibiotics, restoring antibiotic susceptibility with adjuvants is undoubtedly a rational option. As naturally occurring compounds, resveratrol and capsaicin could be extracted from many natural plants, due to various antimicrobial properties, they have received significant attention. Herein, the synergistic activity of colistin combined with resveratrol and capsaicin against mcr-1 -positive Escherichia coli were investigated by checkerboard method and time-killing assays. The in-depth molecular mechanisms were elucidated by scanning electron microscopy, fluorescent probe experiments, transcriptome and metabolome analysis. Molecular docking assay was taken to analyse potential interactions between resveratrol/capsaicin and MCR-1. Finally, the in vivo efficacy of combined therapy against mcr-1- positive Escherichia coli was assessed. Our results demonstrated that colistin combined with resveratrol and capsaicin acted synergistic activity against mcr-1- positive Escherichia coli both in vivo and in vitro . Further mechanistic studies showed that the combined therapy could exacerbate cell membrane damage, increase membrane permeability, disrupt the homeostasis of PMF, inhibit ATP synthesis, and efflux pump activity. In addition, the combined therapy could inhibit central carbon metabolism, and reduce tricarboxylic acid cycle and oxidative phosphorylation. Moreover, molecular docking assay revealed resveratrol/capsaicin could bind to MCR-1 stably. Our study indicated that colistin in combination with resveratrol and capsaicin as a novel therapy could provide a trustworthy foundation to establish the treatment plan for mcr-1- positive Escherichia coli.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Qianjin Li,Rui Li,Mengdi Wang,Jinjin Wang,Tingting Wang,Yu Jin,Jianlin Li,Fenying Wang
Development of rapid, low-cost, and sensitive sensors for monitoring Escherichia coli (E. coli) O157:H7 is very necessary and urgent to ensure food safety. In this study, we developed two fluorescent artificial receptor-based sensors via a boronate affinity molecular imprinting strategy targeting E. coli O157:H7. Fluorescein- and rhodamine-grafted artificial receptors were synthesized using bacterial surface glycoproteins and lipopolysaccharides as the molecular-sized templates to create the specific imprinted cavities. The fluorescent sensors can achieve the recognition within 5 min, displaying cross-reactivity factors of 2.6–40.6 (fluorescein) and 1.5–18.4 (rhodamine), and ultra-sensitive detection limits of 7 CFU/mL (fluorescein) and 2 CFU/mL (rhodamine). The fluorescent artificial receptor-based sensors showed spiking recovery rates in the range of 81 %∼101 %, exhibiting high accuracy as the classical plate counting method (71 %∼112 %) in milk and tap water samples. This strategy establishes a universal platform for constructing high-performance fluorescent sensors for rapidly screening pathogenic bacteria in food safety.
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ANALYTICA CHIMICA ACTA
·
2025
·
IF 6
Jiaqi Niu,Jinhui Liu,Ping Guo,Min Du,Wanqing Wu,Ziyang Zhang,Ye Ning,Dedi Zhou,Haidong Cao
As a common contaminating bacterium, Escherichia coli (E. coli) has caused severe harm in various fields such as food, healthcare, and the environment. Traditional detection methods for Escherichia coli, owing to factors like high cost and low efficiency, are unable to meet the detection requirements at the present stage. Therefore, the development of a simple, rapid, and highly efficient detection method for Escherichia coli represents an urgent issue that needs to be addressed promptly. This study focused on the development of a highly selective molecularly imprinted electrochemical sensor for E. coli. Molecularly imprinted polymers (MIPs) were prepared by electropolymerization on the surface of glassy carbon electrode using o-phenylenediamine as the functional monomer, aminated metal-organic frameworks (MOFs) and carbon nanotubes (CNTs) as the composites, and bovine serum albumin (BSA) was added into the polymer film to attenuate the non-imprinting effect. The linear range of the sensor was 10-10 7 CFU/mL and the detection limit was 5.2 CFU/mL. Good recovery rates were shown in real samples of drinking water, milk and orange juice. In addition, the good binding ability of the E. coli template molecule to the functional monomer o-phenylenediamine was verified by molecular docking and molecular dynamics (MD) simulations. This study was able to detect E. coli in 20 min, which provides a more open idea for the application of rapid detection of E. coli on-site, as well as the construction of molecularly imprinted electrochemical sensors and the analysis of the binding mechanism between template molecules and functional monomers.
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