JOURNAL OF RARE EARTHS
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2012
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IF 0.901
Aimei CHEN,Qingshan SHI,Yousheng OUYANG,Yiben CHEN
This study aimed to delineate the antibacterial mechanism of rare-earth ion Ce 3+ to the target organism Escherichia coli cell, and the most important purpose was to identify its biological effect of increasing the E. coli cell membrane permeability. The antibacterial activities of Ce 3+ to E. coli cells were tested, and then the permeability of outer membrane (OM) and inner membrane (IM) were studied by N-phenyl-1-naphthylamine (NPN) and o -nitrophenyl-β-D-galactopyranoside (ONPG) methods separately. Through these experiments we concluded that the E. coli cells grown to log phage were more sensitive to Ce 3+ than the ones not at this stage; the structure of membrane was destroyed and the permeability of both OM and IM was obviously increased by Ce 3+ ; there should be certain interactions between Ce 3+ and some proteins inside the cell, which impeded the physiological activities of bacteria.
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JOURNAL OF BIOTECHNOLOGY
·
2025
·
IF 3.9
Zhaoyuan Zhang,Jiehu Liu,Meng Wang,Yang Li,Minglei Hou,Jiaren Cao,Jing Wu,Lingqia Su
Nicotinamide mononucleotide (NMN) serves as a crucial precursor in the biosynthesis of NAD + and has garnered significant attention in the food, dietary supplement, and cosmetic industries. This study engineered an Escherichia coli strain capable of high NMN production. Firstly, the strain with reduced NMN degradation and the ability to transport NMN extracellularly was constructed. Meanwhile, the gene encoding nicotinamide phosphoribosyltransferase ( pncA ) was disrupted to minimize substrate nicotinamide (NAM) degradation. Then, the induction starting point was optimized to alleviate the metabolic burden on the engineered strain. Subsequently, systematic remodeling of E. coli 's glucose metabolism was conducted to enhance its suitability for NMN production by overexpressing key enzymes of the pentose phosphate pathway (Zwf and Gnd), knocking out genes related to the Entner-Doudoroff pathway ( gntR and edd ), and further attenuating the glycolytic pathway. Then, we concentrated on optimizing the cellular metabolic state, meticulously balancing intracellular redox homeostasis. Finally, using glucose and 2 g/L of NAM as substrates, the extracellular NMN yield reached 4.96 g/L, which is the highest yield reported so far in similar research. These findings contribute to the commercial production of NMN and offer valuable insights for constructing efficient cell factories for other nucleotide compounds.
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高影响因子
FOOD CONTROL
·
2014
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IF 2.819
Suxia Shen,Tiehua Zhang,Yuan Yuan,Songyi Lin,Jingyue Xu,Haiqing Ye
Gram-negative Escherichia coli (ATCC 8735) and Gram-positive Staphylococcus aureus (ATCC 3101) were selected as model bacteria to determine the antimicrobial mechanism of cinnamaldehyde . Several techniques were utilized to investigate the effects of cinnamaldehyde on food-borne bacterial membranes. The ultraviolet (UV) absorption and electrical conductivity of the culture supernatant were used to determine membrane integrity. β-Galactosidase activity was determined to detect inner membrane permeability. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed to observe bacterial morphology. Samples from both strains exposed to cinnamaldehyde showed higher UV absorptions, conductivity values, and β-Galactosidase activities compared with the control group and displayed a rapid rise trend. Thereafter, the values stabilized at a relatively steady state. SEM shows that treated E. coli and S. aureus cell samples exhibited rough cell membranes with particulate matter, and some of the S. aureus cells split due to deep wrinkle formation and distortion, unlike the control group. TEM shows that the bacteria treated with cinnamaldehyde exhibited numerous abnormalities, including cytoplasmic membrane separation from the cell wall, cell wall and cell membrane lysis, cytoplasmic content leakage, cytoplasmic content polarization, cell distortion, and cytoplasmic content condensation. These results indicate that bacterial cell morphology, membrane integrity, and permeability are damaged when the E. coli and S. aureus cells are exposed to the minimum inhibitory concentrations of cinnamaldehyde (0.31 mg/mL). In addition, the higher the cinnamaldehyde concentration, the more serious the bacterial membrane damage is.
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JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Weiping Cai,Fei Dang,Yujun Wang
Mercury sulfide nanoparticles (HgS NPs) are ubiquitous in nature and are methylated to neurotoxic methylmercury (MeHg) by microorganisms. However, there is a paucity of knowledge regarding the biokinetics of HgS NPs in microorganisms. Here, the biokinetic uptake and efflux of HgS NPs in the model bacterium ( Escherichia coli ) were quantified and compared with those of Hg-dissolved organic matter complexes (Hg-DOM). The results demonstrate that the uptake of HgS NPs was time- and concentration-dependent. The uptake rate constant of HgS NPs was 0.031 ± 0.006 L g −1 h −1 , which was 2.4-fold higher than that of Hg-DOM. Meanwhile, the internalized Hg in E. coli was depurated, as evidenced by the presence of Hg-containing NPs in the culture media. The efflux rate constant of HgS NPs and Hg-DOM were comparable (0.028 ± 0.007 h −1 vs. 0.031 ± 0.009 h −1 ). Consequently, HgS NPs exhibited a significantly higher bioconcentration factor (BCF; 1107 ± 63 L kg⁻ 1 ) than Hg-DOM (419 ± 57 L kg⁻ 1 ), suggesting their enhanced bioavailability and therefore greater methylation potential in Hg-methylating bacteria. These results demonstrate the unique characteristics of HgS NP uptake kinetics, which are essential for capturing their bioaccumulation mechanisms and providing more reliable and accurate risk assessments.
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MOLECULES
·
2025
·Vol. 30
·期 10
·2122
·
IF 4.6
Zhinan Wang,Xiaowei Li,Liang Zhao,Saiwa Liu,Jingjing Du,Xi Jia,Lirui Ge,Jian Xu,Kexin Cui,Yu Ga,Jinxiu Wang,Xi Xia
The emergence ofmcr-1-mediated colistin resistance has become a critical global health concern, highlighting the urgent need for innovative approaches to restore colistin’s therapeutic potential. In this study, we evaluated the antibacterial activity of four matrine-type alkaloids—namely, matrine, oxymatrine, sophocarpine, and sophoramine—againstmcr-1-positiveEscherichia coli. While these alkaloids showed limited efficacy when used alone, the combination of matrine with colistin exhibited remarkable synergistic effects, as demonstrated by checkerboard assays and time-kill curve analyses. The matrine–colistin combination caused minimal erythrocyte damage while effectively attenuating resistance development in vitro. This synergy was further corroborated in a murine infection model, where the combination significantly reduced bacterial loads in target tissues. Mechanistic studies revealed that the matrine–colistin combination enhances antimicrobial activity by disrupting bacterial membrane integrity, increasing intracellular colistin accumulation, and triggering reactive oxygen species-mediated oxidative damage. Collectively, these findings highlight the potential of matrine as a promising adjuvant to overcome colistin resistance, providing a novel therapeutic approach to address the challenge of infections cause by multidrug-resistant Gram-negative bacteria.
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2026
·Vol. 252
·期 10
·387
·
IF 4.2
Wang Haoyu,Liu Zhen,Wang Ningning,Feng Fada,Zhu Ruiyu,Yan Keping
As a novel non-thermal sterilization method, pulsed light (PL) has been widely employed in the food industry to control microbial contamination. However, the antimicrobial mechanism underlying PL treatment remains poorly understood. This study investigated the antimicrobial mechanism of PL against Escherichia coli , focusing on PL‑induced alterations in cellular morphology, ultrastructure, biochemical composition, intracellular leakage, metabolic activity, and membrane integrity. Results from scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that PL treatment severely disrupted the morphology and cellular integrity of E. coli , inducing numerous micro-damages on the bacterial surface and causing alterations in surface mechanical properties. Fourier transform infrared spectroscopy (FT-IR) indicated significant changes in the membrane fatty acids and chemical structure of E. coli in PL-treated samples. Confocal laser scanning microscopy (CLSM) demonstrated severe morphological damage to PL-treated cells, which compromised cell membrane integrity and led to the leakage of intracellular DNA and proteins. Furthermore, PL treatment inhibited energy metabolism and biosynthesis, resulting in a sharp decline in metabolic activity. Concurrently, PL treatment induced a dramatic increase in intracellular reactive oxygen species (ROS) levels, thereby contributing to structural disruption and metabolic collapse from both internal and external pathways, ultimately accelerating cell death. Finally, PL exhibited remarkable sterilization efficacy in the inactivation of E. coli , PL (1.36 J/cm 2 of cumulative fluence) achieved a log reduction greater than 6 in bacterial (10⁷ CFU/mL) inactivation experiment. In the analysis of sterilization in different spectral bands of PL, we found that the UVC band contributes most significantly to bacterial inactivation. These results indicate that PL is an effective technical method for inactivating E. coli .
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JOURNAL OF BIOTECHNOLOGY
·
2026
·
IF 3.9
Kefa Hu,Zhipeng Qi,Xiaode Huang,Lei Wang,Xiaomeng Zhang,Shaoheng Tang
Lavandulol and its acetate ester, lavandulyl acetate, are valuable irregular monoterpenes found in lavender essential oil, widely utilized in the food and cosmetic industries. Due to the limitations of extraction from natural plant resources, developing sustainable microbial cell factories for their production is of great interest. Here, we report the first de novo biosynthesis of lavandulol and lavandulyl acetate in Escherichia coli . Initially, a heterologous mevalonate (MVA) pathway was coupled with lavandulyl diphosphate synthase (LPPS) to establish the biosynthetic route from glycerol. To relieve pathway bottlenecks, we overexpressed the endogenous dITP/XTP pyrophosphatase RdgB, which efficiently facilitated the dephosphorylation of the precursor lavandulyl diphosphate (LPP), increasing lavandulol titers to 42.87 mg/L. Subsequently, the alcohol acyltransferase ATF1 from Saccharomyces cerevisiae was identified as the most effective enzyme for acetylating lavandulol. By integrating ATF1 into the pathway and optimizing both the host strain and fermentation process, we achieved a final lavandulyl acetate titer of 89.43 mg/L. This study establishes a promising prokaryotic platform for the efficient biosynthesis of high-value irregular monoterpenes.
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BioDesign Research
·
2025
·
IF 4.7
Peiling Wu,Haofeng Chen,Guojun Yang,Haoyu Qin,Qian Zhang,Yuxin Chen,Dongjiang Lin,Yang Zhang,Shuyong Lin,Shizhen Wang,Jifeng Yuan
2-Hydroxyisovalerate (2-HIV) is a value-added chemical that is widely applied in the synthesis of bioactive compounds and polymers. Here, we report an underexplored metabolic route for the de novo production of S -type 2-HIV ( S -HIV) in Escherichia coli . In particular, we identified promiscuous activity of 4-hydroxymandelate synthase (HmaS) from Amycolatopsis orientalis towards the conversion of 2-keto-4-methyl-pentanoate (2-KMP, an immediate precursor for L-leucine) to S -HIV. Next, we designed a variant HmaS (S201F) with abolished activity for mandelate and 4-hydroxymandelate synthesis, thereby minimizing byproduct formation. Coupled with systematic optimization of the L-leucine biosynthetic pathway, we achieved de novo production of S -HIV at 8.1 mM (0.95 g/L) in shake flasks and 33.9 mM (4.0 g/L) in 2-L fed-batch fermentation. In summary, this work represents the first time to realize the efficient synthesis of S -configuration 2-HIV in metabolically engineered E. coli .
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Microbial Cell Factories
·
2023
·Vol. 22
·期 1
·1-12
·
IF 6.4
Yang Haiquan,Zhang Kunjie,Shen Wei,Chen Lei,Xia Yuanyuan,Zou Wei,Cao Yu,Chen Xianzhong
Background The tobacco leaf–derived cembratriene-ol exhibits anti-insect effects, but its content in plants is scarce. Cembratriene-ol is difficult and inefficiently chemically synthesised due to its complex structure. Moreover, the titer of reported recombinant hosts producing cembratriene-ol was low and cannot be applied to industrial production. Results In this study, Pantoea ananatis geranylgeranyl diphosphate synthase (CrtE) and Nicotiana tabacum cembratriene-ol synthase (CBTS) were heterologously expressed to synthsize the cembratriene-ol in Escherichia coli . Overexpression of cbts* , the 1-deoxy- d -xylulose 5-phosphate synthase gene dxs , and isopentenyl diphosphate isomerase gene idi promoted the production of cembratriene-ol. The cembratriene-ol titer was 1.53-folds higher than that of E . coli Z17 due to the systematic regulation of ggpps , cbts* , dxs , and idi expression. The production of cembratriene-ol was boosted via the overexpression of genes ispA , ispD , and ispF . The production level of cembratriene-ol in the optimal medium at 72 h was 8.55-folds higher than that before fermentation optimisation. The cembratriene-ol titer in the 15-L fermenter reached 371.2 mg L − 1 , which was the highest titer reported. Conclusion In this study, the production of cembratriene-ol in E . coli was significantly enhanced via systematic optimization. It was suggested that the recombinant E . coli producing cembratriene-ol constructed in this study has potential for industrial production and applications.
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ANALYST
·
2023
·Vol. 148
·期 18
·4414-4420
·
IF 4.2
Xinyi Zhong,Yuan Deng,Qiling Yang,Sirui Yi,Haiyan Qiu,Lanlan Chen,Shanwen Hu
As a crucial indicator in food and water safety testing, the detection of Escherichia coli plays a significant role in maintaining environmental sanitation and promoting public health. Herein, based on the electrochemical activity characteristics of E. coli, we established an enhanced electrochemiluminescence aptasensor for E. coli analysis. This study presents a new method for accurate identification by utilizing a double aptamer recognition system. Specifically, a nano-cadmium sulfide (CdS) modified aptamer was used for primary labeling, while a second aptamer was immobilized on a graphene/chitosan composite electrode for re-capture. The use of two aptamers improves the accuracy of the identification process. Furthermore, the application of an electrode potential facilitates continuous electron transfer between the electrode and electrochemically active microorganisms, resulting in an enhanced electroluminescence signal in relation to the metabolic status. This strategy possesses better sensitivity, accuracy, and stability, demonstrating its potential for E. coli analysis.
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MICROBIAL PATHOGENESIS
·
2022
·
IF 3.848
QiMing Tian,SiMin Wei,HongRui Su,ShuMei Zheng,ShuYa Xu,MingJiang Liu,RuoNan Bo,JinGui Li
The continuous emergence of multidrug-resistant (MDR) bacteria has posed an increasingly serious public health threat which urges people to develop some alternatives. Gallic acid (GA) is a natural ingredient in many traditional Chinese medicines , which has many biological activities, such as antibacterial, and antiseptic. Here, clinical isolates of MDR Escherichia coli ( E. coli ) were used to evaluate the antibacterial effect of GA and the underlying mechanism. The results revealed that GA exerted bactericidal activity and inhibited the formation of bacterial biofilm. GA enhanced the activities of ceftiofur sodium or tetracycline against E. coli , and facilitated antibiotic accumulation in bacteria. Further analysis of morphological alterations and efflux pump gene expressions confirmed that GA damaged outer and inner membranes, and suppressed the mRNA expressions of acrA, acrB, tolC, acrD and acrF involved in membrane permeability . In addition, GA showed protective effects against bacterial infection and improved the survival rates of Galleria mellonella and BALB/c mice. These data highlight a better understanding of GA against bacteria and provide an alternative strategy for MDR bacterial infection.
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NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 42
·19413-19420
·
IF 3.3
Zongqiang Li,Jingjing Li,Xu Wang,Qianru Li,Jingru Zhu,Yuying Yao,Zhiqiang Guo,Yu Wang,Su Liu,Jiadong Huang
Escherichia coli (E. coli) is a common Gram-negative bacterium that is widely distributed in nature and is susceptible to natural and random genetic factors. It is a pathogenic factor for many diseases. Sensitive and specific detection of E. coli is an important means to ensure food safety and prevent foodborne disease outbreaks. Ultrasensitive and specific detection of E. coli is still an urgent problem that needs to be solved. An intuitive and convenient colorimetric assay method with high sensitivity based on a DNAzyme-powered AuNR-DNA walker is proposed here for detection of E. coli. The strategy, dependent on the targeted activation of Mg2+-DNAzyme, starts an efficient DNA walking machine, induces the formation of countless peroxidase-mimicking enzymes, and produces a color change via a chromogenic reaction for visual detection of E. coli. This strategy features several aspects. First, this is the first time that an AuNR-based DNA walker is integrated with a colorimetric assay of E. coli. By combining the DNAzyme-powered AuNR-DNA walker and visual detection via the peroxidase-mimicking enzyme, the detection sensitivity is significantly improved compared to those of previously reported colorimetric-based methods, which provides a paradigm for the development of highly sensitive colorimetric assay methods. Second, an activity-controlled nano-DNAzyme is constructed via target-triggered formation of G-quadruplex DNAzyme to achieve low background and high signal-to-noise detection. In addition, this strategy has the advantages of simple operation, short analysis time, low cost, and easy on-site detection. Therefore, the proposed strategy has the potential for application in the detection of E. coli and related food safety analysis and clinical diagnosis.
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