ACS Omega
·
2024
·
IF 3.7
Xiaofan Wu,Yupo He,Jiaqi Fu,Yanli Zhao
Evaluating the bacterial activity effectively is critical to addressing the challenges posed by bacterial infections. Electrochemistry offers significant advantages in accuracy and cost efficiency compared with methods that are more time-consuming or require expensive instrumentation. This study initially established an electrochemical method for detecting bacterial activity using heat treatment as the pretreatment step. Subsequent optimization of the heat treatment and detection conditions further enhanced the method efficiency. The detection results of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under different heating conditions showed that the peak current values of E. coli and S. aureus were the highest after heating at 50 °C for 15 min. The dynamic changes in the electrochemical signals from the heat-treated bacteria with alteration in heating conditions were indicated to be related to the effects of heating on the external structure and purine metabolism of the bacterial cells. Although heat-treated E. coli and S. aureus exhibited similar peak potentials, different substances were observed to have contributed to these potentials. A positive linear correlation was observed between the peak current and bacterial concentration. Compared to the plate counting method, the electrochemical method detected the activity changes in E. coli and S. aureus from the logarithmic to the stationary phase earlier. The findings support the broad application of electrochemical methods in microbial detection and provide valuable insights into the purine metabolism of heat-stressed bacteria.
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JOURNAL OF APPLIED MICROBIOLOGY
·
2017
·Vol. 122
·期 3
·676-685
·
IF 2.099
Lin W.,Guan X.,Cao J.,Niu B.,Chen Q.
AimsThis study focuses on the bactericidal mechanism of the new combination of disinfectant glutaraldehyde‐didecyldimethylammonium bromide (GA‐DDAB) against Escherichia coli.Methods and ResultsEscherichia coli were exposed to GA‐DDAB, and assays for cell morphology, K+ and Ca2+ leakage, H+‐ATPase activity and DNA degradation were performed. GA‐DDAB damaged the cell wall and disrupted cell‐membrane integrity. Leakage of K+ and Ca2+ increased, resulting in significantly lower intracellular concentrations within 60 min of treatment. In addition, H+‐ATPase was inactivated and DNA was degraded.ConclusionsLeakage of intracellular components indicated that GA‐DDAB damaged the cell membrane of E. coli. This may have caused the observed disruption in equilibria of metal ions, inactivation of H+‐ATPase, and DNA damage.Significance and Impact of the StudyUsing a low concentration of GA and DDAB, a new combination disinfectant was developed. GA‐DDAB displayed higher antimicrobial activity than treatment with GA or DDAB alone. Therefore, GA‐DDAB may be a more cost‐effective and efficient antimicrobial agent than others in use today. Furthermore, this study provided a paradigm for developing high‐efficiency disinfectant to help address the growing problem of bacterial resistance.
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Frontiers in Microbiology
·
2021
·
IF 5.64
Xu Jiaqi,Dong Feng,Wu Meixian,Tao Rongsheng,Yang Junjie,Wu Mianbin,Jiang Yu,Yang Sheng,Yang Lirong
Efficient and novel recombinant protein expression systems can further reduce the production cost of enzymes. Vibrio natriegens is the fastest growing free-living bacterium with a doubling time of less than 10 min, which makes it highly attractive as a protein expression host. Here, 196 pET plasmids with different genes of interest (GOIs) were electroporated into the V. natriegens strain VnDX, which carries an integrated T7 RNA polymerase expression cassette. As a result, 65 and 75% of the tested GOIs obtained soluble expression in V. natriegens and Escherichia coli, respectively, 20 GOIs of which showed better expression in the former. Furthermore, we have adapted a consensus “what to try first” protocol for V. natriegens based on Terrific Broth medium. Six sampled GOIs encoding biocatalysts enzymes thus achieved 50–128% higher catalytic efficiency under the optimized expression conditions. Our study demonstrated V. natriegens as a pET-compatible expression host with a spectrum of highly expressed GOIs distinct from E. coli and an easy-to-use consensus protocol, solving the problem that some GOIs cannot be expressed well in E. coli.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Qinggele Borjihan,Quanfu Yao,Huihui Qu,Haixia Wu,Ying Liu,Alideertu Dong
Antibiotic-resistant bacteria contamination in environments imposes great threats to human life health. This research aims to develop novel targeted antibacterial biochars for achieving high selectivity to kill pathogenic Escherichia coli ( E. coli ). The glycopolymer N -halamine-modified biochars ( i.e ., BCPMA-Cl) were synthesized by the modification of biochars with poly[2-(methacrylamido) glucopyranose- co -acrylamide] (P(MAG- co -AM), followed by chlorination treatment. Based on the results of FTIR, turbidity, XPS, and UV–vis, BCPMA-Cl was successfully synthesized and demonstrated to be able to eliminate Staphylococcus aureus ( S. aureus ) and E. coli. Especially, BCPMA-Cl possessed extremely potent to specific-killing 10 4 CFU∙ml −1 of E. coli with lower hemolytic activity (<5%). Additionally, the antibacterial mechanisms of BCPMA-Cl against bacteria were contact-killing and release-killing contributed by active chlorine ( i.e ., Cl + ). Therefore, this work provided a cost-effective and facile approach for preparation of functional biochars used for bacteria-specific therapeutic applications via livestock pollutants as well as showing a promising strategy to avoid bacterial resistance.
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Desalination and Water Treatment
·
2014
·
IF 0.987
Jie Tang,Yunjun Hu,Shams Ali Baig,Tiantian Sheng,Xinhua Xu
The potential of Cr(VI) reduction by Escherichia coli in the presence of soluble Fe(III) was investigated to explore the chemo-biologically mediated reduction process under anaerobic condition. The reduction efficiency of Cr(VI) reached 95% within 24 h. The influences of experimental parameters, including initial pH, temperature, Fe(III) dosage, carbon source, and chelating agent, were also investigated. The highest efficiency of reduction was observed when pH was 5.8 and temperature was 32°C. Amendments of culture medium with Fe(III) and citric-3Na enhanced Cr(VI) reduction, while the addition of EDTA-2Na inhibited the process. Analysis showed that soluble Fe(III) enhanced the reduction process by shuttling electrons from bio-reduced Fe(II) to Cr(VI) in a coupled biotic-abiotic cycle and hence, Cr(VI) was reduced to Cr(III) followed by deposition to sludge.
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ACS Omega
·
2024
·
IF 3.7
Min Zhou,Liyuan Wei,Chongzhi Wu,Wei Chen,Zhengju Tang
Cytidine 5′-monophosphate (CMP) was widely applied in the food and pharmaceutical industries. Currently, CMP is mainly produced by enzyme catalysis. However, the starting materials for enzyme catalysis were relatively expensive. Therefore, seeking a low-cost production process for CMP was attractive. In this study, Escherichia coli (E. coli) was systematically modified to produce CMP. First, a the cytidine-producing strain was constructed by deleting cdd, rihA, rihB, and rihC. Second, the genes involved in the pyrimidine precursor competing pathway and negative regulation were deleted to increase cyti dine biosynthesis. Third, the deletion of the genes that caused the loss of CMP phosphatase activity led to the accumulation of CMP, and the overexpression of the rate-limiting step genes and feedback inhibition resistance genes greatly increased the yield of CMP. The yield of CMP was further increased to 1013.6 mg/L by blocking CMP phosphorylation. Ultimately, the yield of CMP reached 15.3 g/L in a 50 L bioreactor. Overall, the engineered E. coli with a high yield of CMP was successfully constructed and showed the potential for industrial production.
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BIOORGANIC CHEMISTRY
·
2025
·
IF 4.7
Jianianhua Luo,Jiahui Xu,Qi Li,Lulu Wu,Jianjun Pei,Linguo Zhao
Indican, abundant in plant stems and leaves, serves as a precursor for indigo and indirubin, possessing application potential in many industries. In this study, a multi-faceted experimental strategy for producing indican utilizing tryptophan as the starting material in E. coli was established. This system incorporated the synergistic action of TnaA, MeFMO, and PtUGT2 M91A/S145A , a mutant with a 20 % increase in activity of glycosyltransferase PtUGT2, all co-expressed within the bacterial host. Both a UDP-glucose recycling system and an NADPH regeneration system were incorporated for donor regeneration. Finally, a co-culture system aimed at reducing metabolic burdens was designed. After optimization, a maximum yield of 1043 mg/L was achieved, with a molar conversion rate of 48.1 %, representing an almost 14-fold improvement over the performance of a single strain. This study offers a plant-independent synthesis process for indican, paving a new path for year-round indican production.
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Bioengineering-Basel
·
2024
·Vol. 11
·期 10
·1030
·
IF 3.8
Tuo Song,Xiaozhen Diao,Jun Cheng,Yang Man,Boyu Chen,Haixing Zhang,Wenhui Wu
As an essential thrombolytic agent, the tissue plasminogen activator receives increasing attention due to its longer half-life, lower immunogenicity, and easier administration, which are superior to other thrombolytic agents. In this study, the isolated and purified plasminogen activator from the sandworm (Perinereis aibuhitensis) was expressed inE.coli(Escherichia coli) to investigate its potential for simplifying the development process. The sandworm plasminogen activator was previously successfully cloned and expressed inE.coliwith low yield and activity in the culture supernatant. This low yield and activity prompted us to optimize its DNA sequence. Furthermore, to raise the efficiency in the separation of the target protein, the protein’s solubility was enhanced by fusing it with maltose-binding protein (MBP) tags. Eventually, the fibrinolytic activity was successfully restored after digestion with tobacco etch virus (TEV) protease. This study provides an innovative method of efficiently expressing and purifying plasminogen activators from sandworm inE.coliand broadens its applications in therapeutic treatment of cardiovascular diseases, including thrombosis, stroke, and coronary atherosclerotic heart disease.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Zhen Tao,Chuanjun Tian,Chunyan Zhong,Bingjie Ji,Wenwen Li,Yongshan Zhao
As microbial resistance and recurrent bacterial infections escalate, the growing understanding of the interplay between antibiotic resistance and tolerance has sparked significant interest in the latter. Previous studies have demonstrated that the deletion of cation/proton antiporters (CPAs) induces bacterial phenotypes, such as slow growth and prolonged lag phases, which contribute to the development of tolerance. This study investigates the role of the NhaA protein in antibiotic tolerance in Escherichia coli using CRISPR/Cas9 gene editing to delete the NhaA protein. Our results suggest that the NhaA protein plays a key role in modulating antibiotic tolerance. In response to NhaA deletion, E. coli adapts through multiple mechanisms, including changes in membrane permeability, enhanced efflux activity, increased membrane fluidity, disruption of the proton motive force (PMF), and a reduction in intracellular ATP levels. These adaptive changes collectively promote the development of antibiotic tolerance. Understanding these tolerance mechanisms could uncover new therapeutic targets, help prevent the emergence of tolerance, or sustain bacteria cells in a tolerant state, providing crucial strategies to combat the rise of antibiotic-resistant bacteria.
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Scientific Reports
·
2016
·Vol. 6
·期 1
·1-13
·
IF 5.228
Fang Yajing,Lu Yulin,Zang Xixi,Wu Ting,Qi XiaoJuan,Pan Siyi,Xu Xiaoyun
Flavonoids are potential antibacterial agents. However, key substituents and mechanism for their antibacterial activity have not been fully investigated. The quantitative structure-activity relationship (QSAR) and molecular docking of flavonoids relating to potent anti- Escherichia coli agents were investigated. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were developed by using the pIC 50 values of flavonoids. The cross-validated coefficient ( q 2 ) values for CoMFA (0.743) and for CoMSIA (0.708) were achieved, illustrating high predictive capabilities. Selected descriptors for the CoMFA model were ClogP (logarithm of the octanol/water partition coefficient), steric and electrostatic fields, while, ClogP, electrostatic and hydrogen bond donor fields were used for the CoMSIA model. Molecular docking results confirmed that half of the tested flavonoids inhibited DNA gyrase B (GyrB) by interacting with adenosine-triphosphate (ATP) pocket in a same orientation. Polymethoxyl flavones, flavonoid glycosides, isoflavonoids changed their orientation, resulting in a decrease of inhibitory activity. Moreover, docking results showed that 3-hydroxyl, 5-hydroxyl, 7-hydroxyl and 4-carbonyl groups were found to be crucial active substituents of flavonoids by interacting with key residues of GyrB, which were in agreement with the QSAR study results. These results provide valuable information for structure requirements of flavonoids as antibacterial agents.
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POULTRY SCIENCE
·
2025
·
IF 4.2
Mengru Chen,Zhenying Wang,Yifei He,Yimin Jia,Lei Wu,Ruqian Zhao
The spleen is a critical secondary immune organ. Various stressors encountered during rearing can induce a stress state in poultry, leading to splenic atrophy. However, the underlying mechanisms remain poorly understood. Moreover, research on how the spleen responds to Escherichia coli ( E. coli ) infection under stress conditions is still limited. In this study, we established a broiler stress model by subcutaneously administrating corticosterone ( CORT ) solution for 7 consecutive days, followed by intramuscularly challenge with avian pathogenic Escherichia coli ( APEC ). The results showed that CORT treatment induced splenic atrophy in broilers. Transcriptomic analysis, combined with TUNEL and PCNA staining results, suggested that this atrophy might be attributed to increased apoptosis and decreased proliferation of spleen cells. Notably, CORT treatment resulted in a reduction in B cell numbers and an increase in the number of heterophil in spleen, indicating that CORT treatment may suppress adaptive immunity while compensatorily enhancing innate immunity to maintain immune homeostasis in spleen. Subsequently, we further examined how CORT pretreatment influenced the spleen immune response to APEC infection. APEC infecton induced splenomegaly, while no significant enlargement was observed in spleen with CORT pretreatment. Transcriptomic analysis showed that the immune response of spleen changed significantly after APEC infection, with or without CORT pretreatment. In addition, compared with APEC infection alone, CORT pretreatment followed by APEC infection resulted in splenic atrophy, with B cell reduction and increased heterophil accumulation. Notably, these heterophil exhibited enhanced antimicrobial peptides production and up-regulated phagolysosome pathways to facilitate pathogen clearance. Moreover, colony stimulating factor 3 receptor ( CSF3R ) and CCAAT/enhancer binding protein beta ( CEBPB ) may serve as key regulators in heterophil maturation, chemotaxis, and function in this process. These results indicate that CORT treatment induce splenic atrophy by inhibiting cell proliferation and promoting apoptosis, while suppressing adaptive immunity and enhancing innate immunity. APEC infection with CORT pretreatment increased heterophil numbers and activity, potentially improving pathogen clearance, CSF3R and CEBPB may contribute to this process.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2026
·Vol. 74
·期 31
·24542-24552
·
IF 6.7
Wang Shangyi,Zhuo Yuqi,Tuly Jamila Akter,Zabed Hossain M.,Zhang Yufei,Zhang Guoyan,Tian Yuehui,Li Jia,Yun Junhua,Qi Xianghui
Caffeic acid (CA) is a valuable phenylpropanoid with
applications
in food, pharmaceutical, and chemical industries. Microbial production
of CA is often limited by the terminal hydroxylation catalyzed by
4-hydroxyphenylacetate 3-monooxygenase (HpaBC). Here, we constructed
a de novo CA biosynthetic pathway in Escherichia coli and enhanced production through systematic metabolic and spatial
engineering. Optimization of l -tyrosine supply and HpaBC
expression increased CA production to 61.0 mg/L. However, further
enhancement of glucose uptake and precursor supply was insufficient,
indicating that hydroxylation remained a major limitation. To address
this, HpaBC was relocated to the periplasm via the Tat pathway, increasing
CA production 4.9-fold to 299.1 mg/L with reduced byproduct formation.
Further lpp +14 mediated periplasmic remodeling
and fermentation optimization increased shake-flask production to
463.7 mg/L. Finally, fed-batch fermentation achieved 5.1 g/L CA in
a 3 L bioreactor. This study highlights periplasmic engineering as
an effective strategy for improving oxidation-dependent phenylpropanoid
biosynthesis.
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