Biomolecules
·
2026
·Vol. 16
·期 1
·152
·
IF 4.8
Zeyan Xu,Chuyu Qin,Ruohan Zhang,Mengting Wu,Anqi Cui,Wei Chen,Lu Chen,Daqing Gao,Ruihua Shi
Adherent-invasiveE. coli(AIEC) is closely related to inflammatory bowel disease (IBD). However, its pathogenic mechanism has not yet been fully elucidated. Using a BLASTP search, we discovered that the amino acid sequence of a putative protein (UFP37798.1) in the AIEC LF82 strain is highly homologous to some regulators in the SlyA family. We named it EruA. We displayed the secondary structures of EruA using bioinformatics, overexpressed the His6-tagged EruA protein using SDS-PAGE, and dissected the genetic organization of theeruAchromosomal region using 5′RACE. We constructed aneruAdeletion mutant (ΔeruA) and a complementary strain (CΔeruA) of the LF82 strain. The transcriptomes of wild-type (WT) and ΔeruA bacteria were compared using RNA sequencing and qRT-PCR, thereby identifying 32 differentially expressed genes (DEGs). Based on YASARA software and EMSA analysis, EruA directly binds to the consensus sequences (PfimAand PtnaB) in the promoter region of thefimAandtnaBgenes from these DEGs. By using a super-resolution confocal microscope (SCM), counting CFUs of colonies on plates, indole quantification, and crystal violet staining of biofilms adhered to tubes or 96-well plates, we found that EruA activates thefimAto promote bacterial adhesion to intestinal epithelial cells and activates thetnaBto enhance bacterial indole production and biofilm formation. Moreover, EruA helps AIEC resist environmental stress and enhances bacterial survival within macrophages as well as loading in mouse tissues. Notably, EruA promotes AIEC colonization in the colons of mice and exacerbates intestinal inflammation caused by bacterial infection in mice with DSS-induced inflammatory colitis, manifested by weight loss, colon length shortening, and pathological changes in colon tissues. Therefore, EruA plays a key role in the pathogenicity of AIEC.
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Microbiology Spectrum
·
2022
·Vol. 10
·期 4
·
IF 9.043
Mohamed Sharaf,Alaa H. Sewid,H. I. Hamouda,Mohamed G. Elharrif,Azza S. El-Demerdash,Afaf Alharthi,Nada Hashim,Anas Abdullah Hamad,Samy Selim,Dalal Hussien M. Alkhalifah,Wael N. Hozzein,Mohnad Abdalla,Taisir Saber
Surface-growing antibiotic-resistant pathogenic bacteria such as Escherichia coli and Staphylococcus aureus are emerging as a global health challenge due to dilemmas in clinical treatment. Furthermore, their pathogenesis, including increasingly serious antimicrobial resistance and biofilm formation, makes them challenging to treat by conventional therapy. Therefore, the development of novel antivirulence strategies will undoubtedly provide a path forward in combatting these resistant bacterial infections. In this regard, we developed novel biosurfactant-coated nanoparticles to combine the antiadhesive/antibiofilm properties of rhamnolipid (RHL)-coated Fe3O4 nanoparticles (NPs) with each of the p-coumaric acid (p-CoA) and gallic acid (GA) antimicrobial drugs by using the most available polymer common coatings (PVA) to expand the range of effective antibacterial drugs, as well as a mechanism for their synergistic effect via a simple method of preparation. Mechanistically, the average size of bare Fe3O4 NPs was ~15 nm, while RHL-coated Fe3O4@PVA@p-CoA/GA was about ~254 nm, with a drop in zeta potential from −18.7 mV to −34.3 mV, which helped increase stability. Our data show that RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs can remarkably interfere with bacterial growth and significantly inhibited biofilm formation to more than 50% via downregulating IcaABCD and CsgBAC operons, which are responsible for slime layer formation and curli fimbriae production in S. aureus and E. coli, respectively. The novelty regarding the activity of RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs reveals their potential effect as an alternative multitarget antivirulence candidate to minimize infection severity by inhibiting biofilm development. Therefore, they could be used in antibacterial coatings and wound dressings in the future.IMPORTANCE Antimicrobial resistance poses a great threat and challenge to humanity. Therefore, the search for alternative ways to target and eliminate microbes from plant, animal, and marine microorganisms is one of the world’s concerns today. Furthermore, the extraordinary capacity of S. aureus and E. coli to resist standard antibacterial drugs is the dilemma of all currently used remedies. Methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) have become widespread, leading to no remedies being able to treat these threatening pathogens. The most widely recognized serotypes that cause severe foodborne illness are E. coli O157:H7, O26:H11, and O78:H10, and they display increasing antimicrobial resistance rates. Therefore, there is an urgent need for an effective therapy that has dual action to inhibit biofilm formation and decrease bacterial growth. In this study, the synthesized RHL-Fe3O4@PVA@p-CoA/GA biosurfactant NPs have interesting properties, making them excellent candidates for targeted drug delivery by inhibiting bacterial growth and downregulating biofilm-associated IcaABCD and CsgBAC gene loci.
研究领域:
微生物学
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纳米技术
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药学
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生物医学工程
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Catalysts
·
2023
·Vol. 13
·期 2
·371
·
IF 3.9
Xue-Jiao Liu,Bao-Di Ma,Xiao-Mei Wu,Yi Xu
A recombinantE. coli, expressing nitrilase fromAcidovorax facilis72W with dual-site expression plasmid pRSFduet (E. colipRSF-AfNit2), was constructed. It showed higher soluble expression of nitrilase than that in the pET21a plasmid. The recombinant nitrilase can efficiently catalyze the hydrolysis of 3-cyanopyridine to nicotinic acid. The whole cells ofE. colipRSF-AfNit2 were immobilized by using sodium alginate/glutaraldehyde/polyethylene imine as the best immobilized reagents. The immobilized cells showed 95% activity recovery and excellent mechanical strength, with improved thermal stability and pH stability. They also retained 82% of initial activity after nearly two months of storage at 4 °C. A semi-continuous packed-bed bioreactor (sPBR) filled with the immobilized cells was studied for efficient production of nicotinic acid. After optimization, the highest space–time yield of 1576 g/(L·d) was obtained on 0.8 M substrate concentration at 2 mL/min of flow rate. The sPBR was repeatedly operated for 41 batches, keeping 100% conversion in the presence of 30 mM CaCl2. Finally, 95 g of nicotinic acid were obtained at 90% yield after separation and purification. The developed technology has potential application value.Keywords:nitrilase;cell immobilization;nicotinic acid;reaction optimization;semi-continuous packed-bed bioreactor
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Journal of Materials Chemistry B
·
2023
·
IF 7
Xintian Zhang,Pingping Wu,Xiaoli Hao,Jiamiao Liu,Zhengjun Huang,Shaohuang Weng,Weifeng Chen,Lingling Huang,Jianyong Huang
Infections caused by Gram-negative bacteria still pose a clinical challenge. Although nanomaterials have been developed for antibacterial treatments, a systematic evaluation of the mechanisms and intervention models of antibacterial materials toward Gram-negative bacteria is still lacking. Herein, antibacterial quaternized carbon dots (QCDs) were synthesized via a one-step melting method using anhydrous citric acid and diallyl dimethyl ammonium chloride (DDA). The QCDs exhibited effective broad-spectrum antibacterial activity and enhanced inhibitory ability towards Gram-negative bacteria. The antibacterial mechanism of the QCDs with respect to Gram-negative bacteria was investigated through the characterization of bacterial morphology changes, the absorption modes of the QCDs on bacteria, and the potential generation of reactive oxygen species by the QCDs. The QCDs showed low toxicity in different cells, and did not cause hemolysis. The QCDs were administered via intraperitoneal injection to treat acute peritonitis in mice infected with E. coli. Routine blood examination, magnetic resonance imaging, and pathological analysis were undertaken and it was found that, similar to the positive control group treated with gentamicin sulfate, the QCDs exhibited a therapeutic effect that eliminated infection and inflammation. This study explores a controllable synthetic strategy for the synthesis of active carbon dots with antibacterial activity, a material that is a promising candidate for new treatments of Gram-negative bacterial infections.
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TALANTA
·
2022
·
IF 6.556
Ming Li,Wenying Lu,Yuhao Mao,Xuchun Qiu,Daolin Du
It is desired and urgently needed to improve the sensitivity of immunochromatography assay (ICA) for hazardous chemicals. In this work, an enhanced ICA strip was established and evaluated for simultaneous, semi-quantitative and quantitative detection of ochratoxin A (OTA) and aflatoxin B 1 (AFB 1 ). The signal strategy based on gold growth on the surface of the E. coli K12 carrier was recommended, which was successfully self-assembled on the enhanced ICA with a double test line pattern. When used as a novel carrier, the E. coli K12 could provide a larger surface area, better biocompatibility and high loading capacity, which was of great help to improve the performance of the ICA. By the naked eye, the semi-quantitative limit of detection (semi-Q-LOD) reached 0.03 ng/mL for both OTA and AFB 1 (17-fold and 33-fold lower than the conventional ICA strip). By the digitized strip reader, the quantitative LODs (Q-LODs) were all identified as 0.01 ng/mL for two mycotoxins (10-fold improvement), with detection ranges of 0.01–0.5 ng/mL for OTA and 0.01–0.2 ng/mL for AFB 1 . Furthermore, the high reliability and applicability of the ICA were confirmed by its good correlation with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The advantages of the improved sensitivity, high efficiency and cost savings had been reflected for the ICA. This study could provide an important reference method for the sensitive, simultaneous, rapid and on-site monitoring of multicomponent contaminants.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Jialin Jia,Stefanos Giannakis,Dong Li,Boyin Yan,Tao Lin
A novel catalytic system for effective photocatalytic inactivation of Escherichia coli ( E. coli ) was constructed by anchoring Ag nanoparticles (AgNPs) on silane coupling agent (SCA) pretreated TiO 2 nano-tube arrays (Ag/SCA/TiO 2 NTAs). Morphology and structural analyses revealed that SCA could disperse AgNPs evenly on TiO 2 NTAs, thus inducing a superior surface plasmon resonance (SPR) effect. Ag/SCA/TiO 2 NTAs catalyst exhibited excellent inactivation performance when in the presence of peroxymonosulfate (PMS) and visible light (VL), with 6-log E. coli was completely inactivated within 60 min, which was 5.3, 12.5 and 13.2 times higher than that of Ag/SCA/TiO 2 NTAs/VL, PMS/VL and Ag/SCA/TiO 2 NTAs/PMS/dark systems, respectively. Additionally, the photocatalyst exhibited a highly reusable property, with the inactivation performance almost unchanged after ten cycles of uses with minimal Ag leaching. The inactivation mechanism analysis demonstrated that both radical (SO 4 •- , OH) and non-radical (h + , 1 O 2 ) pathways involved in E. coli inactivation, and SCA played a pivotal role in the production of reactive species. Chloride ions (Cl − ) greatly enhanced the inactivation efficiency, while bicarbonate (HCO 3 − ) and phosphate (H 2 PO 4 − ) showed an inhibitory effect. Humic acid (HA) displayed a dual effect on inactivation performance, where the low concentration of HA facilitated the bacteria inactivation, while the higher dose suppressed bacteria inactivation. Moreover, the system exhibited excellent inactivation performance in tap water . This work first used SCA as the binder to fix AgNPs on TiO 2 NTAs for VL photocatalytic inactivation of bacteria with the assistance of PMS, which was expected to provide some insights into the practical treatment of drinking water .
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Yanna Shao,Zhengzheng Wang,Jihang Xie,Zhenjun Zhu,Ying Feng,Shubo Yu,Liang Xue,Shi Wu,Qihui Gu,Jumei Zhang,Qingping Wu,Juan Wang,Yu Ding
We presented a colorimetric/fluorescent dual-mode immunochromatographic assay (ICA) for the sensitive detection of Escherichia coli O157:H7. The use of polydopamine (PDA)-modified gold nanoparticles (AuNPs) with broadband absorption allowed for excellent colorimetry signals for the ICA detection. Moreover, the absorption spectrum of PDA-AuNPs significantly overlaps with the excitation and emission spectra of ZnCdSe/ZnS quantum dots (QDs), resulting in effective quenching of the QDs fluorescence due to the inner filter effect. The fluorescence intensity changes induced by PDA-AuNPs were utilized for the sensitive detection of E. coli O157:H7, achieving a detection limit of 9.06 × 10 1 CFU/mL, which was 46-fold lower than that of traditional AuNPs-based immunoassay. The proposed immunosensor exhibited the recovery rate between 80.12% and 114.69% in detecting actual samples, indicating its reliability and satisfactory accuracy. This study provides insights into dual-mode signal outputs and the ICA development for food safety applications.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 11
·11990-12000
·
IF 3.056
Cui Yanping,Thathsarani Nimesha,Peng Liang,Gao Ya,Lei Lidan,Zhou Zhengwei,Liang Lili,Shi Xiaoyan
Innovative paramagnetic one-dimensional (1-D) core-shell Fe-Ag@AgCl visible light-driven photocatalysts are synthesized through a template-assisted electrodeposition method trailed by FeCl 3 in-situ oxidation. The metallic nature of Fe-Ag@AgCl is confirmed through scanning electron microscopy (SEM) and crystal nature through X-ray diffraction (XRD). The controllable diameter of Fe-Ag is obtained through the selection of hollow size of the polycarbonate (PC) template. Electron impedance spectroscopy (EIS) confirms through the introduction of Fe to the Ag core that has prolonged the recombination of electron and hole. Escherichia coli ( E. coli ) are employed as the target bacteria to evaluate the photocatalytic disinfection performances. A total of 1.30 mg of Fe-Ag@AgCl is proved to be able to completely inactivate 10 7 CFU (colony forming units)/mL after 120 min of visible light irradiation. The transition electron microscopy (TEM) confirms the stability of the material after the photo reaction. As Fe-Ag@AgCl possesses magnetic properties, the material is recovered through the application of an external magnetic field. SEM images and results of 3D emission extraction matrix (EEM) depict that the bacteria cell death is caused by membrane permeability changes caused by the reduction of membrane associated proteins.
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JOURNAL OF BIOTECHNOLOGY
·
2015
·
IF 2.871
Yue-De Cao,Yu-Cai He,Hao Li,Guo-Yin Kai,Jian-He Xu,Hui-Lei Yu
Hyoscyamine 6 β -hydroxylase (H6H, EC 1.14.11.11), an α-ketoglutarate dependent dioxygenase catalyzes the hydroxylation of (−)-hyoscyamine and the subsequent epoxidation of 6 β -hydroxyhyoscyamine to form scopolamine, a valuable natural alkaloid. In this study, random mutagenesis and site-directed saturation mutagenesis were used to enhance the hydroxylation activity of H6H from Anisodus acutangulus ( Aa H6H). A double mutant, Aa H6H M1 (S14P/K97A), showed a 3.4-fold improved hydroxylation activity compared with the wild-type enzyme, and the in vivo epoxidation activity was also improved by 2.3 times. After 34 h cultivation of Escherichia coli cells harboring Aa h6h m1 in a 5-L bioreactor with a working volume of 3 L, scopolamine was produced via a single-enzyme-mediated two-step transformation from 500 mg L −1 (−)-hyoscyamine in 97% conversion, and 1.068 g of the product were isolated, corresponding to a space-time yield of 251 mg L −1 d −1 . This study shows that the protein engineering of some key enzymes is a promising and effective way for improving the production of rare natural products such as scopolamine.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Ting Wu,Huashan Sun,Wenyao Wang,Bin Xie,Zhengjie Wang,Jianqi Lu,Anming Xu,Weiliang Dong,Jie Zhou,Min Jiang
Enzymatic PET recycling has emerged as a promising green solution in addition to mechanical recycling, but low soluble expression levels of the inherently hydrophobic PET hydrolases hinder large-scale applications. Here, we propose a novel strategy for enhanced production of FastPETase in Escherichia coli using co-expression of molecular chaperones from Ideonella sakaiensis . Co-expression of cognate DnaK and DnaJ chaperones significantly increased soluble FastPETase expression (up to 2.5-fold), surpassing commercial chaperone plasmids. Furthermore, a combinatorial approach employing co-expression of DnaK/DnaJ chaperones and fusion of FastPETase with the VNp6-tag significantly boosted FastPETase secretion, yielding over 2 g/L of target protein in a 5-l bioreactor. Notably, the crude FastPETase in fermentation broth displayed comparable PET hydrolysis effects to the purified enzyme. This work not only provides new insights into the process of chaperones in protein folding but also suggests a novel and efficient strategy for producing recombinant proteins.
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Food Bioscience
·
2024
·
IF 4.8
Chenghui Zhang,Changzhu Li,Tariq Aziz,Metab Alharbi,Haiying Cui,Lin Lin
Food processing environments contaminated with E. coli O157 :H7 and forming biofilms will be a continuous source of contamination, leading to foodborne illness and food spoilage. Now, the main countermeasure is chemical disinfectants, but the use of disinfectants may cause the development of drug-resistant bacteria and other negative effects. Therefore, there is an urgent need to find novel antimicrobial agents. Quorum-sensing inhibitors (QSI) are a promising strategy to control biofilm formation. This study aimed to screen the optimal QSI of E. coli O157 :H7 from plant-derived small molecules by biofilm and QS inhibitory activities and to validate their effectiveness in combination with disinfectants. In addition, the inhibition mechanism of gallic acid on biofilm formation was further explored. Gallic acid was screened as the QSI of E. coli O157 :H7, and its AI-2 inhibitory activity against LuxS/AI-2 QS system reached 95.54% and 98.89% after treatment with 1/2 MIC gallic acid for 4 h and 6 h, respectively. It inhibited biofilm formation by affecting flagellar assembly, chemotaxis, and expression of adhesion factor-related genes, which interfered with the transition of bacteria from reversible to irreversible adhesion. In beef broth simulation system, the inhibition rate was greater than 90.00% in all gallic acid and benzalkonium chloride combination groups. Therefore, gallic acid can be a potential antimicrobial synergist in the food industry, combined with disinfectants to control E. coli O157 :H7 biofilms while avoiding the development of resistance.
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Molecular Catalysis
·
2025
·
IF 4.9
Bo Fan,Run Lin,Xinyu Gu,Ruibing Cui,Ruiqing Yang,Yu-Cai He
Alcohols can be extensively used in the production of fine chemicals, such as fuel additives, food supplements and pharmaceutical intermediates, which can be acquired by the reduction of biomass-derived aldehyde. In this study, the recombinant Escherichia coli KPADH was genetically constructed through the co-expression of alcohol dehydrogenase from Kluyveromyces polysporus and glucose dehydrogenase from Bacillus subtilis . Biomass-derived aldehydes were biologically converted into alcohols in a benign system. In deep eutectic solvent (DES) choline chloride:glycerol-H 2 O (choline chloride:glycerol, 10 wt %) containing E. coli KPADH cells (0.1 g/mL), HMF (50 mM), glucose (2 equivalents), and NAD + (0.1 μM/mM HMF), bioreduction of HMF into 2,5-bis(hydroxymethyl)furan was implemented, acquiring a high yield of 98.1 % within 8 h. Other biobased compounds, such as isovanillin, vanillin, p -hydroxybenzaldehyde, furfural, and benzaldehyde were also converted into their corresponding alcohols. According to the molecular docking results, HMF had the lowest CDOCKER energy value of -27.422 kcal/mol. It was found that HMF displayed strong binding affinity with E. coli KPADH, resulting in enhanced binding stability and superior catalytic reduction activity. This study demonstrated a green and highly effective biocatalytic method for the synthesis of biobased alcohols.
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