ACS Omega
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2026
·
IF 5.2
Zhaobo Hu,Yan Guo,Peishuo Cao,Keyan Wei,Zongjie Ma,Boxin Li,Dong Li,Liang Zhou,Chang-ye Hui
Abstract This work presents an engineered single-plasmid, dual-pigment whole-cell biosensor for simultaneous colorimetric detection of Pb(II) and Hg(II). To address the challenge of signal interference in cocontaminated environmental samples, a Pb(II)-responsive PbrR regulatory module driving indigo biosynthesis (blue, 620 nm) and an Hg(II)-responsive MerR module driving deoxyviolacein biosynthesis (purple, 570 nm) were integrated into Escherichia coli TOP10. The orthogonal decoupling of the two pigment pathways, combined with a unified 10 h induction protocol, enables independent chromogenic readout of both metals from a single cultivation. Dose-response assays afforded a broad linear dynamic range for Pb(II) of 0.977–2000 μM (R2 = 0.9503) with a limit of detection (LOD) of 0.977 μM, alongside nanomolar sensitivity for Hg(II) with a linear range of 0.244–250 nM (R2 = 0.9800) and an LOD of 0.244 nM. A two-dimensional cross-concentration matrix experiment further demonstrated that the two detection channels maintain distinguishable dose-dependent responses under coexposure conditions, with crosstalk remaining within an acceptable range. Robust performance was retained in spiked surface water and seawater matrices, yielding Pb(II) LODs of 0.244 μM (surface water) and 0.488 μM (seawater), and Hg(II) LODs of 0.488 nM (surface water) and 0.977 nM (seawater). These detection limits approach or fall below relevant environmental regulatory thresholds, including the Class III surface-water standard for Hg(II). This self-contained, instrument-free pigment-based approach enables naked-eye discrimination of both metals in a standard microplate assay, offering a low-cost, high-throughput screening platform that complements standard instrumental methods for on-site environmental monitoring and emergency pollution response.
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MICROCHEMICAL JOURNAL
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2026
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IF 5.2
Mengyue Liu,Shouyi Dou,Mingyang Lv,Shuhua Wei,Yongcun Yan,Xinxin Li,Yemin Guo,Xia Sun,Shicai Xu
Herein, a novel protease-free colorimetric strategy was proposed for the ultrasensitive biosensing of Escherichia coli ( E. coli , strain CMCC 44102). This strategy employed an E. coli whole-cell aptamer for specific recognition and dual-catalyst hairpin assembly (DCHA)-mediated cyclic amplification. Specifically, four nucleic acid strands (Apt, H1, H2, and S) mediated DCHA cyclic amplification, while the G-quadruplex/hemin complex acted as a DNAzyme to catalyze the oxidation of ABTS 2− for signal generation. The formation of H2-S complexes and dissociated G strands depended on the quantity of Apt-induced DCHA. The relationship between Apt and E. coli concentration was established by measuring the activity of the G-quadruplex/hemin DNAzyme. Under optimal conditions, the proposed method exhibited a sensitivity of 69 CFU·mL −1 with a linear range of 1 × 10 2 to 1 × 10 7 CFU·mL −1 . Furthermore, this method demonstrated good selectivity, with recovery rates ranging from 92.80% to 99.20% and relative standard deviations (RSD) below 3.65% in tap water and milk samples. In summary, this strategy is label-free, protease-free, cost-effective, and rapid. Given its modular design, substitution with aptamers specific to other targets would extend this approach to a wide range of applications.
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MicrobiologyOpen
·
2026
·Vol. 15
·期 2
·e70258
·
IF 3.6
Siqi He,Yuxin Wang,Wenli Wang,Yanhua Li,Zhiyun Zhang
The formation of Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) mixed biofilms challenges the treatment of bacterial infections. In this study, the synergistic effect of plant essential oils cinnamaldehyde (CA) and carvacrol (CV) on inhibiting S. aureus and E. coli mixed biofilms formation was investigated. The Q value of CA and CV combination on inhibiting mixed biofilms formation was 2.28, suggesting their synergistic effect. Furthermore, CA/CV nanoemulsion was prepared, which further enhanced the inhibitory effect. CA/CV nanoemulsion could significantly inhibit the mixed biofilms formation at 64 μg/mL by reduction of bacterial adhesion and motility, polysaccharide intercellular adhesin (PIA) synthesis, and the inhibition of LuxS/AI‐2 expression. In the S. aureus and E. coli infected implant model of mice, CA/CV NEs demonstrated prominent inhibitory effect on the formation of S. aureus and E. coli biofilms, and simultaneously reduced the bacterial burden. The study prepared Cinnamaldehyde‐Carvacrol nanoemulsions (CA/CV NEs) through high‐energy emulsification. In a mouse infection model, CA/CV NEs exhibited a synergistic inhibitory effect on the formation of Staphylococcus aureus–Escherichia coli mixed biofilms, reducing PIA, LuxS/AI‐2, adhesion, athletic ability, and extracellular protein.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2026
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IF 6.7
Wenjing Fan,Changgeng Li,Runze Zhao,Tang’en Shi,Liangwen Li,Zhichao Chen,Zichen Yu,Ling Ma,Siyu Zhao,Qingyang Xu
The demand for β-thymidine primarily stems from its role as a raw material and intermediate in antiviral drug production. To address this, β-thymidine was synthesized de novo using Escherichia coli. We engineered a high-yielding β-thymidine strain based on the orotate high-yielding strain Ora14–4. First, we introduced the pyrFE gene cluster from Bacillus subtilis to direct the metabolic flux toward β-thymidine synthesis. Genes involved in β-thymidine catabolism and precursor branching were knocked out, and key enzymes in the β-thymidine biosynthetic pathway were optimized. Enhancing the folate cycle and glycine cleavage system provided sufficient one-carbon donors for deoxythymidine monophosphate synthesis. The Entner-Doudoroff pathway from Zymomonas mobiliz was introduced to enable NADPH production. Last, a growth-adaptive promoter regulated tmk gene expression to minimize carbon loss. The final β-thymidine titer was 25.4 g/L, with a conversion rate of 0.079 g/g glucose, which is, to the best of our knowledge, the highest titer reported to date for de novo microbial production of β-thymidine.
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Food Bioscience
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2026
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IF 6.2
Yakun Zhao,Jian Chen,Huan Li,Xi Zhao,Zhixiang Wang,yuan Yao,Xuye Lang,Yanbo Wang
Medium-chain fatty acids (MCFAs) are high-value flavor enhancers critical for improving the sensory quality of processed foods like dried-fish. Traditional plant-derived MCFAs production faces sustainability limitations, necessitating efficient microbial alternatives. Here, we engineered Escherichia coli ( E. coli ) for high-yield MCFAs synthesis via targeted metabolic rewiring. In this study, we optimized a platform based on de novo fatty acid synthesis to increase the production of MCFAs. Using the pTargetF and pCas dual plasmid knockout system, single gene knockout was sequentially performed on E . coli , they were IdhA and poxB genes, which consume pyruvate, as well as the pta gene, which consumes acetyl CoA, and the aas gene that can reduce the toxicity of MCFAs to the host, followed by multi gene combination knockout. All combination knockout strains express thioesterase gene (CpFatB 1 ). The best-performing strain, strain MG9 (MG1655△ aas △ pta [pTrc99a-CpFatB 1 ]), was selected for further optimization. After 144h of cultivation with D-fructose, 680 mg/L of C8 fatty acid was obtained. We explored purification methods for C8 fatty acid, and purified C8 fatty acid reached 99.75% purity with 82.15% recovery yield. Crucially, applying these biosynthesized C8 fatty acid to industrial fish drying elevated the kinds of flavor compounds similarity to traditional products from 38.57% to 68.57%. This work establishes a sustainable platform for high-purity MCFAs production and demonstrates their direct utility in enhancing premium food flavors, offering a scalable solution for the food industry.
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APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2026
·
IF 4.2
Hua Li,Fangjuan Li,Yajie Shi,Xinxin Wang,Xiaomeng Wang,Guanyu Zheng,Lixiang Zhou,Barth F. Smets
The dissemination of extracellular antibiotic resistance genes (eARGs) through horizontal gene transfer poses a serious threat to global water safety. While Escherichia coli MG1655 is known to employ intracellular nucleases to defend against foreign DNA, the potential of its cell lysate to enzymatically degrade plasmid-borne eARGs and disrupt their environmental propagation remains unexplored. This study demonstrated that E. coli MG1655 cell lysate can degrade the plasmid-borne ampR gene by 99.9% within 48 h, and the maximum first-order degradation rate constant measured by long amplicon qPCR was 0.20 h−1 at the selected dosage state. This degradation eliminated the ability of the plasmid pUC19 for transformation, reducing it to below detectable levels (<10−6 transformants/recipients). The DNase I, produced by the chromosomal endA gene, was identified as the likely nuclease driving eARG cleavage. Environmental conditions critically modulated degradation efficiency: humic acid (50 mg/L) decreased the rate by 41.3%, while divalent cations (e.g., Mg2+) increased the rate by 1.65-fold. To transmit laboratory findings into real-world application, a polyacrylamide hydrogel-immobilized lysate (PAM-cell lysate) was engineered, which outperformed free lysate in treating plasmid-spiked real wastewater, sustaining 99.9% of ampR removal across three treatment cycles. This research demonstrated that PAM-cell lysate, without genetic modification, can be a cost-effective and scalable solution for attenuating the spread of eARGs in water, advancing the development of complementary enzymatic strategies for sustainable water remediation.
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ULTRASONICS SONOCHEMISTRY
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2022
·
IF 9.336
Okon Johnson Esua,Da-Wen Sun,Clement Kehinde Ajani,Jun-Hu Cheng,Kevin M. Keener
Linear (first-order) and non-linear (Weibull, biphasic, and log-logistic) models were evaluated for predicting the inactivation kinetics of Escherichia coli and Listeria monocytogenes on grass carp treated by a novel technique (UPFB) combining ultrasound (US) with plasma functionalized buffer (PFB). Results showed that UPFB was more effective for inactivating bacteria when compared with individual applications of US or PFB with reductions of 3.92 and 3.70 log CFU/g for Escherichia coli and Listeria monocytogenes , respectively. Compared with the linear model, the three non-linear models presented comparable performances and were more suitable for describing the inactivation kinetics with superior adj-R 2 (0.962–0.999), accuracies (0.970–1.006) and bias factors (0.995–1.031), and by assessing the strengths of evidence, weights of evidence and evidence ratios for the models, the biphasic model was identified as the best fit model. The current study provided new insights into the effective evaluation of decontamination methods.
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BIOELECTROCHEMISTRY
·
2022
·
IF 5.76
Fan Shi,Baoli Wang,Lijun Yan,Bei Wang,Yanyan Niu,Lisi Wang,Wei Sun
Sensitive and accurate detection technology for pathogenic bacteria is of great social and economic significance in foodborne disease and food safety. In this paper, a novel portable electrochemical DNA biosensor for the detection of specific DNA sequence of Escherichia coli ( E. coli) O157: H7 was constructed. To enhance the performance of the electrochemical sensor, a functionalized nitrogen-doped carbonized polymer dots in-situ grown on few-layer black phosphorus ( [email protected] ) was synthesized and used as the modifier on the surface of screen-printed electrode. Combining gold nanoparticles as immobilization matrix and methylene blue as electrochemical indicator, the analytical performance of this electrochemical DNA biosensor was evaluated using standard complementary ssDNA sequence in the linear concentration range from 1.0 × 10 −19 to 1.0 × 10 −6 mol/L with a low detection limit as 3.33 × 10 −20 mol/L (3 σ). Furthermore, the portable electrochemical DNA biosensor was proposed based on polymerase chain reaction amplification for the detection of the E. coli O157: H7 genomic DNA from chicken meat, which verified the feasibility for practical samples detection. The research has great theoretical and practical significance for the development of electrochemical biosensor of pathogenic bacteria.
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Innovative Food Science & Emerging Technologies
·
2021
·
IF 5.916
Qiao He,Lianjiao Zhang,Zhehao Yang,Tian Ding,Xingqian Ye,Donghong Liu,Mingming Guo
In this study, the antibacterial activities of thyme essential oil nanoemulsions (TEON) prepared by ultrasonication (US) and high-pressure homogenization (HPH) were evaluated via minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-killing curve analyses. TEON-US presented superior bacteriostatic and bactericidal effects , which was found to be correlated with its better physicochemical characteristics (including smaller droplet size and higher zeta potential) compared to TEON-HPH. The underlying antibacterial mechanisms were specifically investigated targeting cell membranes of Escherichia coli O157:H7 (Gram-negative bacterium) and Staphylococcus aureus (Gram-positive bacterium). Thereinto, membrane disintegrations were observed followed by massive leakage of cytoplasmic inclusions . Furthermore, the membrane dysfunctions (involving membrane potential depolarization and fluidity reduction) were likely associated with the modifications seen in the fatty acid composition upon TEONs exposure, and ultimately causing bacterial death. These results deciphered the mode of antibacterial action of TEONs, providing a critical theoretical basis for their future application in food matrix.
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Microbial Drug Resistance
·
2021
·Vol. 27
·期 3
·337-341
·
IF 3.431
Mingzhi Wang,Bo Ma,Yunfeng Ni,Xiaoyan Xue,Mingkai Li,Jingru Meng,Xiaoxing Luo,Chao Fang,Zheng Hou
Multidrug resistance poses a severe threat to public health and urgently requires new solutions. The natural product chelerythrine (CHE) is a benzophenanthridine alkaloid with antimicrobial potential. In this study, CHE was effective against seven gram-positive bacterial strains, and the minimum inhibitory concentrations (MICs) ranged from 2 to 4 μg/mL. By contrast, CHE showed inferior antibacterial activities against 11 gram-negative strains, and the MICs varied from 16 to 256 μg/mL. We also determined the synergistic/additive effects of combining CHE with nine currently used antibiotics. CHE restored the antibacterial efficacy of the antibiotics against methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamases producing Escherichia coli. This study suggests that the combination of CHE with conventional antibiotics may be a promising strategy to combat infections caused by multidrug-resistant organisms.
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FOOD CONTROL
·
2021
·
IF 5.548
Shan Shan,Yanmei Huang,Zhaohong Huang,Zhonger Long,Chengwei Liu,Xuelong Zhao,Keyu Xing,Xiaoyue Xiao,Jintao Liu,Yunhong Huang,Weihua Lai,Daofeng Liu
Shiga toxin-producing Escherichia coli (STEC) is known as a kind of foodborne pathogens that can produce Shiga toxin type1, type 2, or both, encoded by stx1 and stx2 genes, respectively. Rapid and accurate detection of STEC and stx1 / stx2 subtyping assay in food and environment is essential for foodborne outbreak investigation. In this study, a method for the accurate and rapid subtyping of STEC single colony using asymmetric polymerase chain reaction (asPCR) combined with lateral flow immunoassay (LFIA) was established. AsPCR was conducted using biotinylated stx1 and digoxin-labeled stx2 primers to obtain several single stranded DNA amplicons labeled with biotin or/and digoxin. Subsequently, these amplicons were tagged with specific probes labeled with carboxylate-modified red polystyrene microspheres using sequential hybridization. Finally, STEC with different Shiga toxin gene types could be distinguished depending on the appearance of different test lines on an LFIA strip. Thus, the STEC single colony could be identified and subtyped accurately and conveniently using this method. This method showed high specificity. Twenty-four strains of STEC in milk were detected and subtyped using our method, which combines asPCR with LFIA.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 9
·1-10
·
IF 6.232
Wang Shujuan,Xu Dongpo,Ding Chengchao,Tian Yachen,Ge Kangjie,Guo Liang,Li Jie,Dong Qingli,Huang Yong,Liu Qing
Cobalt-based zeolitic imidazolate framework nanosheets (ZIF-67) with oxidase-like catalytic activities as an immunoprobe were employed to enhance the sensitivity of an immunoassay. ZIF-67 was synthesized via the solvothermal method using 2-methylimidazole and cobalt dichloride as substrates. A colorimetric immunoassay for Escherichia coli ( E. coli ) O157:H7 was designed. Preparation of the immunoprobe involved self-polymerized dopamine being applied for the surface modification of ZIF-67 nanosheets in order to bind to the antibody, which was used to identify E. coli O157:H7. ZIF-67 catalyze the oxidation of 3,3′,5,5′-tetramethylbiphenyl (TMB) and produced a color change from colorless to blue. Upon reaction termination, the absorbance was measured at 450 nm. By combining ZIF-67@PDA catalyzed chromogenic reaction with antibody recognition and magnetic separation, the limit of determination is 12 CFU mL −1 and the linear range is 30 to 3.0 × 10 8 CFU mL −1 . The proposed colorimetric immunoassay was successfully utilized to detect E. coli O157:H7 of spiked food samples.
Graphical abstract
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危险品化学品经营许可证（带存储）