JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2024
·
IF 5.7
Jie Zheng,Hongxiang Liu,Jiwen Zhang,Bo Yu
L-Azetidine-2-carboxylic acid (L-Aze), a natural nonproteinogenic amino acid found widely in plants, has recently been identified as an environmentally friendly agent for controlling powdery mildew with low toxicity. In this study, a biological route for L-Aze production via the methionine salvage pathway (Yang Cycle) was first in silico designed for Escherichia coli. Subsequently, systematic engineering strategies were employed to enhance the production efficiency, including the enhancement of the 5-phosphoribosyl 1-pyrophosphate (PRPP) supply, construction of the ATP-adenine cycle, and engineering of the strain’s resistance to L-Aze. The final strain produced L-Aze from glucose with a titer of 568.5 mg/L. The antifungal activity of the produced L-Aze in the fermentation broth was also confirmed for treating powdery mildew in cucurbits. This approach not only provides a sustainable and green route for pesticide production to control powdery mildew but also expands our understanding of the exogenous construction of the Yang Cycle in E. coli.
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MICROCHIMICA ACTA
·
2025
·Vol. 192
·期 4
·1-12
·
IF 5.3
Liu Mengyue,Xu Shicai,Marrazza Giovanna
Multivalent engineering aptamers (multi-Apts) adaptive and specific to whole Escherichia coli ( E. coli : CMCC 44102) cells based on hybridization chain reaction (HCR) were constructed for the first time. The dissociation constant ( K d ) value for these multi-Apts was 48 nM, demonstrating a higher affinity than that of monovalent aptamers (mono-Apts) ( K d = 102 nM). Furthermore, the reaction equilibrium of multi-Apts was achieved within 20 min, with a reaction rate twice that of mono-Apts. To validate the exceptional performance of these multi-Apts, they were employed as recognition elements in conjunction with gold nanoparticles (AuNPs) colorimetric assays for the all-in-one rapid detection of E. coli . This method exhibited a linear detection range from 1 × 10 2 to 1 × 10⁷ CFU mL⁻ 1 , achieving a limit of detection (LOD) as low as 19 CFU mL⁻ 1 . The recovery of this method in tap water and milk were 85.7% to 101% and 81.8% to 98.2%, respectively. The results indicated that this method not only provided a wide detection range but also exhibited high sensitivity and accuracy. Additionally, this study demonstrated that multi-Apts possessed greater application potential in the detection of macromolecular substances such as bacteria. In short, this work provided a novel approach for rapid and all-in-one detection of E. coli in food. Graphical
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ANALYST
·
2013
·Vol. 138
·期 12
·3388-3393
·
IF 3.969
Xiaochun Jiang,Kun Chen,Jing Wang,Kang Shao,Tao Fu,Feng Shao,Donglian Lu,Jiangong Liang,M. Frahat Foda,Heyou Han
A new electrochemical immunosensor based on solid-state voltammetry was fabricated for the detection of Escherichia coli (E. coli) by using graphene oxide–Ag nanoparticle composites (P-GO–Ag) as labels. To construct the platform, Au nanoparticles (AuNPs) were first self-assembled on an Au electrode surface through cysteamine and served as an effective matrix for antibody (Ab) attachment. Under a sandwich-type immunoassay format, the analyte and the probe (P-GO–Ag–Ab) were successively captured onto the immunosensor. Finally, the bonded AgNPs were detected through a solid-state redox process in 0.2 M of KCl solution. Combining the advantages of the high-loading capability of graphene oxide with promoted electron-transfer rate of AuNPs, this immunosensor produced a 26.92-fold signal enhancement compared with the unamplified protocol. Under the optimal conditions, the immunosensor exhibited a wide linear dependence on the logarithm of the concentration of E. coli ranging from 50 to 1.0 × 106 cfu mL−1 with a detection limit of 10 cfu mL−1. Moreover, as a practical application, the proposed immunosensor was used to monitor E. coli in lake water with satisfactory results.
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BIOTECHNOLOGY LETTERS
·
2018
·Vol. 40
·期 5
·837-845
·
IF 1.846
Hui Chang-Ye,Guo Yan,Yang Xue-Qin,Zhang Wen,Huang Xian-Qing
Objectives To improve the Pb 2+ biosorption capacity of the potential E. coli biosorbent, a putative Pb 2+ binding domain (PbBD) derived from PbrR was efficiently displayed on to the E. coli cell surface. Results The PbBD was obtained by truncating the N-terminal DNA-binding domain and C-terminal redundant amino acid residues of the Pb 2+ -sensing transcriptional factor PbrR. Whole-cell sorbents were constructed with the full-length PbrR and PbBD of PbrR genetically engineered onto the surface of E. coli cells using Lpp-OmpA as the anchor. Followed by a 1.71-fold higher display of PbBD than PbrR, the presence of PbBD on the surface of E. coli cells enabled a 1.92-fold higher Pb 2+ biosorption than that found in PbrR-displayed cells. Specific Pb 2+ binding via PbBD was the same as Pb 2+ binding via the full-length PbrR, with no observable decline even in the presence of Zn 2+ and Cd 2+ . Conclusions Since surface-engineered E. coli cells with PbBD increased the Pb 2+ binding capacity and did not affect the adsorption selectivity, this suggests that surface display of the metal binding domain derived from MerR-like proteins may be used for the bioremediation of specific toxic heavy metals.
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Environmental Science-Processes & Impacts
·
2026
·
IF 3.9
Sadiq Naveed,Xinwei Zhou,Dongqiang Zhu
Extracellular reductive dechlorination of chlorinated aliphatic hydrocarbons (CAHs) by non-electroactive bacteria is rarely investigated. In this study, we demonstrated that common bacteria Gram-positive Bacillus subtilis (B. subtilis) and Gram-negative Escherichia coli (E. coli) in aqueous suspensions (1.2 × 108 cells per mL) could dechlorinate a model CAH compound hexachloroethane (HCE, initial 40 µmol L−1) at ratios of 83.7% and 54.1% respectively to pentachloroethane (PCE) and tetrachloroethylene (TCE) after 56 h incubation at pH 7.0 and 30 °C. The majority of the parent compound (HCE) and reaction products (PCE and TCE) present in the extracellular matrix indicated the predominance of extracellular reduction. Removing EPS from bacteria suppressed HCE reduction, while adding extra dissolved EPS slightly enhanced HCE reduction. The enhanced reduction of HCE by low-molecular-weight EPS (<3 kDa) relative to bulk EPS of B. subtilis and its counterpart high-molecular-weight EPS (>3 kDa) indicated that low-molecular-weight EPS were more enriched in active reducing agents. Additionally, dechlorination of HCE by electrochemically reduced glutathione and disodium anthraquinone-2,6-disulfonate or juglone suggested that thiol groups and quinones were involved as reducing agents and electron mediators, respectively. These findings underscore a previously unknown process of extracellular reductive dechlorination of CAHs by common non-electroactive bacteria and the key role played by EPS.
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INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
·
2026
·
IF 4.6
Rongrong Dong,Yifei Wang,Lei Song,Jiayin Wang,Chun Yang,Xufeng Ji,Qi Zhou,Hao Wang,Xinhua Guo,Jiancheng Xu
Background Carbapenem-resistant Escherichia coli (CREC) producing New Delhi metallo-beta-lactamase (NDM) poses a substantial threat to global public health. Prompt detection of CREC is essential for effective patient management and to curb the spread of resistance. Objective This study aims to establish a rapid and reliable detection method for NDM-producing CREC using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) in conjunction with machine learning (ML) techniques. Methods Clinical isolates of E. coli were collected from the First Hospital of Jilin University’s clinical laboratory from August 2018 to December 2022. PCR was employed to detect 23 prevalent resistance genes in the isolates. Protein profiles were analyzed by MALDI-TOF MS with a cooperative matrix consisting of (E)-propyl α-cyano-4-hydroxylcinnamylate (CHCA-C3) and α-cyano-4-hydroxycinnamic acid (CHCA). By comparative analysis of nine ML algorithms, the optimal Random Forest (RF) algorithm was identified and used to find the NDM specific ion peaks. Furthermore, the NDM gene was cloned into the standard E. coli strain ATCC 25922 to verify the reliability of these specific peaks. Results A total of 154 E. coli strains were categorized into three groups: 45 CREC strains, 58 extended-spectrum beta-lactamase (ESBL)-producing strains, and 51 non-CREC, non-ESBL strains. PCR amplification identified 12 resistance genes. The established ML model with RF algorithm exhibits excellent discriminative ability, achieving an AUC of 0.993 and an AP of 0.997. Four specific peaks ( m/z 5132, m/z 5209, m/z 6350, and m/z 6371) of NDM were identified using the cooperative matrix. In contrast, the traditional CHCA matrix revealed no specific peaks. Furthermore, the specific peaks at m/z 5132 and m/z 5209 were detected in the MALDI-TOF MS spectra of the recombinant E. coli strain ATCC 25922-PZY01/NDM, which directly correlated with the expression of the NDM gene. Conclusion The integration of MALDI-TOF MS with ML techniques, facilitated by the cooperative matrix approach, has enabled the swift and precise identification of NDM-producing CREC. This advancement significantly enhances the effectiveness of clinical management and the control of hospital-acquired infections.
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CURRENT MICROBIOLOGY
·
2026
·Vol. 83
·期 8
·424
·
IF 2.8
Xu Jialin,Yan Bohu,Fu Qifu,Li Haoyu,Jiang Zonghan,Zhou Rushun,Chen Xiaojun,Sun Zhiliang,Wang Yanan,Li Jiyun
In response to the critical challenge of colistin resistance in animal production, we examined the occurrence and genetic features of mcr-1 -positive E. coli isolates collected from livestock in Hunan province, China, between 2016 and 2021. A total of 1,358 animal samples from chickens and pigs were collected and screened. Monitoring data indicates that nineteen mcr-1 -positive E. coli isolates (1.40%) were identified, and all were resistant to colistin and tetracycline. The prevalence rate of mcr-1 positive E. coli has significantly declined since 2017 and has remained consistently low. Most isolates (89.47%) exhibited multidrug resistance and carried multiple antibiotic resistance genes, including tet (A) , sul3, bla TEM-1B, while a subset of strains (21.05%) harbored quinolone resistance-associated point mutations in gyrA , parC , and parE . Multi-locus sequence typing identified 14 sequence types, with ST48 being the most frequent (21.05%), and five clonal complexes, with CC10 as the predominant lineage (52.63%). Plasmid analysis revealed that 68.42% of the isolates carried plasmids, predominantly IncX4 (36.84%), and 57.89% of isolates harbored conjugative plasmids with complete relaxase and MPF system components. The mcr-1 gene was found within three main genetic arrangements: (i) mcr-1-pap2, (ii)IS Apl1-mcr-1-pap2, and (iii) IS Apl1-mcr-1-pap2- IS Apl1 . These findings highlight the potential for dissemination of mcr-1 in animal-derived E. coli and underscore the importance of monitoring and controlling antimicrobial resistance in livestock.
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MOLECULES
·
2026
·Vol. 31
·期 12
·2039
·
IF 5.1
Xiangyu Wei,Xiumei Song,Wei Huang,Yating He,Yimin Wang,Pinxiu Liu,Lichao Tan,Lin Yang,Zhongwei Chen
The strategy of enhancing biocatalytic activity through the modification of natural cells with nanomaterials has overcome the intrinsic catalytic bottlenecks of bacteria, making significant contributions to energy production and pollution treatment. However, chemically engineered biocatalyst systems remain in their early stages of development. Herein, we report a simple and straightforward strategy for constructing an efficient biocatalyst by incorporating carbon quantum dots (CDs) intoEscherichia coli(E. coli) to enhance the oxygen reduction reaction (ORR) at the cathode of microbial fuel cells (MFCs). The introduction of CDs significantly accelerates extracellular electron transfer and metabolic activity, markedly increases intracellular adenosine triphosphate (ATP) levels, and promotes substrate utilization. Furthermore, the engineeredE. coliexhibits enhanced surface adhesion and increased electronegativity. Electrochemical measurements demonstrate superior ORR activity, delivering a maximum current density of 3.1 mA·cm−2and an onset potential of 0.67 V, outperforming many previously reported biocatalysts. When applied in an MFC system, the modified biocatalyst achieves a maximum power density of 325 μW·cm−2, placing it among the highest-performing systems reported to date. This work provides a facile and cost-effective approach for improving MFC performance and offers a promising design strategy for next-generation biohybrid catalysts.
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WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2026
·Vol. 42
·期 10
·555
·
IF 4.7
Wang Yuhao,Zhou Dongming,Chen Qiong,Wang Changjun,Li Wenhao,Sun Xuewei,Tang Chengliang,Jiang Zhiqiang,Zhang Xuefei,Wang Wenjing,Yang Zhan,Cui Qian
Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7) is a globally significant foodborne pathogen. Infection disrupts the gut microbiota and exacerbates host immune dysfunction. Reuterin, a broad-spectrum antimicrobial metabolite produced by Limosilactobacillus reuteri during glycerol fermentation, exhibits potent antibacterial activity in vitro; however, its in vivo preventive efficacy and underlying mechanisms remain incompletely understood. This study aimed to comprehensively evaluate the protective effects of reuterin prophylaxis and to investigate its potential mechanisms in mitigating EHEC O157:H7 infection through gut microbiota modulation. In a murine infection model, prophylactic administration of reuterin (60 mM) conferred pronounced protection, as evidenced by alleviation of colonic pathology, oxidative stress, and systemic inflammation, together with restoration of intestinal barrier integrity. 16S rRNA sequencing and fecal microbiota transplantation (FMT) demonstrated that reuterin alleviated EHEC O157:H7 infection through gut microbiota remodeling, which was associated with elevated abundances of Ligilactobacillus and Alloprevotella and increased short-chain fatty acids (SCFAs) production. Exogenous SCFAs supplementation was associated with attenuated colonic damage and inflammation, consistent with a potential contribution of these metabolites to the observed protection. Furthermore, our data are compatible with a model wherein SCFAs-mediated activation of the intestinal receptor GPR43 may suppress NF-κB signaling. Collectively, this study provides a foundation for the further development of reuterin as a prophylactic agent against EHEC O157:H7 infection. Graphical abstract Reuterin pretreatment exerted direct antimicrobial effects and was associated with shifts in gut microbial taxonomy and increased SCFAs production. These changes coincided with upregulated GPR43 expression and attenuated NF-κB activation in colonic tissues, correlating with ameliorated oxidative stress and inflammation in EHEC O157:H7-infected mice. While these findings are consistent with a potential role for the SCFAs–GPR43–NF-κB signaling axis in mediating protection, causality regarding specific microbial mediators remains to be established.
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FOOD RESEARCH INTERNATIONAL
·
2026
·
IF 8.8
Liyuan Niu,Huiyi Liu,Xiaoqiao Wu,Ziyue Zhao,Yafei Zhai,Limin Wang,Zhijian Zhang,Qisen Xiang
Freezing induced >80% sublethal injury in Escherichia coli O157:H7 after 21 h. • Injured cells showed membrane damage, ATP depletion, and impaired biofilm formation. • Metabolomics linked freezing injury to pyruvate and fatty acid metabolism. • Resuscitation reactivated nucleotide synthesis, redox balance, and energy production. • Oregano essential oil reduced the sublethal injury ratio in E. coli O157:H7. Freezing stress can induce sublethal injury in foodborne pathogens, allowing injured cells to evade detection and subsequently resuscitate, thereby posing a hidden food safety risk. This study investigated the formation, physiological characteristics, and resuscitation of freezing-induced sublethally injured Escherichia coli O157:H7 at −20 °C and explored the underlying mechanisms using untargeted metabolomics. After 21 h of freezing, the proportion of sublethally injured cells exceeded 80%, accompanied by cell surface collapse, impaired membrane integrity, and depleted intracellular protein and ATP levels. Metabolomic analysis revealed distinct perturbations in pyruvate metabolism, the tricarboxylic acid (TCA) cycle, and fatty acid biosynthesis. Resuscitation in tryptone soy broth at 25 °C for 8 h was accompanied by activation of purine, cysteine and methionine metabolism, glycolysis/gluconeogenesis, and riboflavin metabolism, alongside upregulation of phosphatidylethanolamine indicative of membrane remodeling. Notably, freezing-stressed E. coli cells exhibited significantly enhanced sensitivity to oregano essential oil (OEO), with the sublethal injury ratio decreasing from 79.73% to 22.70% upon OEO treatment at 1/2 × MIC (minimum inhibitory concentration), consistent with the membrane-damage mechanism. These findings provide integrated physiological and metabolomic insights into freezing-induced sublethal injury and support the rational design of membrane-targeting antimicrobials as effective hurdle strategies for frozen food safety. Download: Download high-res image (269KB) Download: Download full-size image
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Gels
·
2026
·Vol. 12
·期 6
·538
·
IF 6.4
Ye Li,Chaofan Zhang,Miao Zhang,Shi Zhou,Yanping Yu,Xiaoyan Yu,Ximing Cui,Xiangge Qin
Achieving in situ and time-resolved monitoring of microbial metabolites without disrupting the microbial growth environment remains a key challenge in electrochemical biosensing. Herein, we propose a self-healing bilayer hydrogel-based solid-state electrochemical sensing platform for the in situ, time-resolved analysis of purine metabolites produced byEscherichia coli(E. coli). This platform integrates an upper Agar culture module and a lower borax-crosslinked poly(vinyl alcohol) (PVA) detection module, forming a contiguous structure that allows metabolites (e.g., guanine, xanthine, hypoxanthine) to migrate across the solid–solid interface for sensitive electrochemical detection. The detection layer exhibits excellent ionic conductivity; when coupled with its robust structural self-healing capacity, the platform achieved a detection limit of 0.05 µM for guanine. ForE. colidetection, a linear response range of 1.1 × 106to 9.5 × 106CFU·mL−1(R2= 0.9974) was obtained, and relative standard deviations (RSDs) of less than 2.34% even after two weeks of storage. Leveraging this integrated design, the platform enables continuous, label-free tracking of bacterial metabolic dynamics throughout all growth phases. Notably, it detects metabolic transition points earlier than traditional plate counting methods and accurately evaluates antibiotic inhibition trends, with results consistent with colony-forming unit (CFU) analysis. This integrated culture–detection architecture thus provides a versatile strategy for functional microbial analysis and rapid antimicrobial susceptibility testing.
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ACS Synthetic Biology
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2026
·
IF 4.5
Tang’en Shi,Yu Miao,Pengjie Sun,Siyu Zhao,Changgeng Li,Zhichao Chen,Zichen Yu,Qingyang Xu
Adenine, a fundamental purine nucleobase, is a vital precursor for the biosynthesis of numerous bioactive nucleosides and nucleotides used in pharmaceutical development and biomedical research. However, sustainable microbial production of adenine is hindered by strict metabolic regulation and product toxicity. Here, we developed a modular engineering strategy in Escherichia coli combining removal of catabolic and transcriptional repression, reinforcement of flux from PRPP to adenine, blocking of competing salvage/branch pathways, growth-phase-dependent control of guaB, feedback-resistant prs/purF, and adaptive laboratory evolution for product tolerance. The resulting plasmid-free and antibiotic-free strain demonstrated superior genetic stability and industrial robustness, achieving an adenine titer of 4.76 g/L (0.18 g/L/h) during a 26-h fed-batch fermentation without selection pressure. This system maintained high cell density and minimal byproduct formation, with a conversion efficiency of 0.025 g/g glucose. To our knowledge, this is the first report of a high-level, plasmid-free adenine production system, establishing a robust platform for the scalable biobased manufacturing of nucleobase-derived ingredients.
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