COLLOIDS AND SURFACES B-BIOINTERFACES
·
2023
·
IF 5.8
Ting Wang,Qiong Yin,Hao yang Huang,Zhenyu Wang,Haixing Song,Xiaoming Luo
Poor drug penetration in hypoxia area of solid tumor is a big challenge for intestinal tumor therapy and thus it is crucial to develop an effective strategy to overcome this challenge. Compared with other bacteria used for construction of hypoxia targeted bacteria micro-robot, the Escherichia coli Nissle 1917 (EcN) bacteria are nonpathogenic Gram-negative probiotic and can especially target and identify the signal molecules in the hypoxic region of tumor, and thus, in this study, we choose EcN to construct a bacteria propelled micro-robot for targeting intestinal tumor therapy. Firstly, the [email protected] with average diameter of 200 nm were synthesized and conjugated with EcN bacteria using EDC/NHS chemical crosslinking method to construct a EcN propelled micro-robot. The motility of micro-robot was then evaluated and the motion velocity of [email protected] was 3.78 µm/s. Compared with [email protected] without EcN driven, EcN bacteria propelled micro-robot transported much more [email protected] into the inner of HCT-116 3D multicellular tumor spheroids . However, the EcN bacteria are non-intracelluar bacteria which lead to the micro-robot can not directly enter into tumor cells. Therefore, we utilized acid-labile linkers of cis-aconitic amido bone to link EcN with [email protected] nanoparticles to achieve the pH sensitive separation of EcN with [email protected] from the micro-robot. At 4 h of incubation, the isolated [email protected] began to enter into the tumor cells through CLSM observation. In vitro live/dead staining results show that [email protected] induced much more cell death than [email protected] at 24 and 48 h of incubation with HCT-116 tumor cells in acid culture media (pH 5.3). For the validation of the therapeutic efficacy of the micro-robot for intestinal tumor, we established the HCT-116 subcutaneous transplantation tumor model. After 28 days of treatment, [email protected] dramatically inhibit tumor growth with tumor volume was around 689 mm 3 , induce much more tumor tissues necrosis and apoptosis. Finally, the toxicity of this micro-robot was investigated by pathological analysis the liver and heart tissues. We expect that the pH sensitive EcN propelled micro-robot here we constructed may be a safe and feasible strategy for intestinal tumor therapy.
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Environmental Science-Nano
·
2023
·Vol. 10
·期 5
·1341-1351
·
IF 7.3
Shuting Fang,Yiquan Huang,Zhangmin Xiang,Rong Zeng,Shulin Zeng,Shuqin Liu
The ever-increasing environmental risks posed by nanoplastics (NPs) have been drawing more concerns to their biological effects, but with limited information on pathogenic bacteria. This work reported the alterations in bacteriological properties of Escherichia coli O157:H7 (E. coli O157:H7) under exposure to polystyrene (PS) NPs of different sizes. Results found that E. coli O157:H7 growth was promoted by the addition of PS-NPs. At environmentally relevant exposure levels, E. coli O157:H7 underwent metabolic adaptation after different PS-NP treatments, showing differentiated responsive volatile metabolic features. Moreover, enzymatic activity analysis suggested that E. coli O157:H7 could address PS-NP-induced oxidative stress mainly via supporting glutathione (GSH) synthesis. Furthermore, it could fuel the TCA cycle through highly expressing regulatory enzymes as well with a greater response to small PS-NPs. Also, there was an observed increase in the expression of the AcrAB-TolC efflux pump after the treatment of PS below 100 nm and with a possible consequence of heightening E. coli O157:H7 resistance. Together, our findings provided the first look into the potential implications mediated by PS nanoparticles on E. coli O157:H7 growth and development and in turn emphasized a potential increased contamination of E. coli O157:H7 as a waterborne pathogen in PS-NP polluted water.
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BIOTECHNOLOGY LETTERS
·
2023
·Vol. 45
·期 8
·993-1000
·
IF 2.7
Peng Shuaiying,Chu Zhongmei,Lu Jianfeng,Li Dongxiao,Wang Yonghong,Yang Shengli,Zhang Yi
The self-sufficient cytochrome P450 BM3 mutant (A74G/F87V/D168H/L188Q) can serve as a biocatalyst for whole-cell catalysis process of indigo. Nevertheless, the bioconversion yield of indigo is generally low under normal cultivation conditions (37 °C, 250 rpm). In this study, a recombinant E. coli BL21(DE3) strain was constructed to co-express the P450 BM3 mutant gene and GroEL/ES genes to investigate whether GroEL/ES can promote the indigo bioconversion yield in E. coli . The results revealed that the GroEL/ES system could significantly increase the indigo bioconversion yield, and the indigo bioconversion yield of the strain co-expressing P450 BM3 mutant and GroEL/ES was about 21-fold that of the strain only expressing the P450 BM3 mutant. In addition, the P450 BM3 enzyme content and in vitro indigo bioconversion yield were determined to explore the underlying mechanism for the improvement of indigo bioconversion yield. The results revealed that GroEL/ES did not increase indigo bioconversion yield by increasing the content of P450 BM3 enzyme and its enzymatic transformation efficiency. Moreover, GroEL/ES could improve the intracellular nicotinamide adenine dinucleotide phosphate (NADPH)/NADP + ratio. Given that NADPH is an important coenzyme in the catalytic process of indigo, the underlying mechanism for the improvement of indigo bioconversion yield is probably related to an increase in the intracellular NADPH/NADP + ratio.
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JOURNAL OF ANIMAL SCIENCE
·
2023
·
IF 3.3
Zuo Jingru,Liu Lianjie,Hou Simeng,Liu Xiaoqiang,Teng Jiang,Li Pei,Liu Xiaotong
Carbapenemase-producing E. coli is a grave public health concern as the potential emergence of resistant strains and their transmission. Isoorientin belongs to a potential antimicrobial flavonoid compound existing in several plants, while the research on the antimicrobial activity of isoorientin is limited thus far. We evaluated the antimicrobial and antibiofilm effects of isoorientin against biofilm-forming carbapenem non-sensitive Escherichia coli (E. coli) from raw milk of goats, and explored its molecular mechanisms. Isoorientin showed obvious antimicrobial ability with the minimum inhibitory concentration (MIC), and it exhibited synergistic activity with traditional antimicrobials against the carbapenem non-sensitive E. coli. Isoorientin could also significantly inhibit the carbapenem non-sensitive E. coli biofilm formation and destroy the established biofilms, with the percentage of inhibition ranging from 27.8% to 75% at MIC, and the corresponding percentage of eradication ranging from 15.3% to 61.6%, respectively. Confocal laser scanning microscopy (CLSM) observation and scanning electron microscopy (SEM) images indicated that the E. coli biofilm reduced in thickness with increasing concentrations of isoorientin. Dose-dependent decrease in eDNA revealed that isoorientin interacted with the extracellular polymeric substances (EPS) of the biofilm. qRT-PCR assay for the biofilm-forming associated genes further confirmed the above results. Overall, these results concluded that the isoorientin has significant antimicrobial and antibiofilm activity against carbapenem non-sensitive E. coli, and has potential application in prevention of food contamination and spoilage.
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PROCESS BIOCHEMISTRY
·
2023
·
IF 4.4
Yu-Chi Tseng,Chengfeng Xue,I-Son Ng
The abundance and biodiversity of intestinal bacteria play a critical role in immune system. Escherichia coli Nissle 1917 (EcN), a tractable probiotic cell has emerged as a ‘smart microbe’ that can provide therapeutic modalities at the sites of disease. Additionally, Lactobacillus rhamnosus GG (LGG) represents one of the key probiotics in clinical studies with the ability to enhance intestinal immunity in symbiosis with other cells. To fully exploit the advantages of EcN and LGG, we optimized the commensal culture medium for LGG and EcN, succeeded by the establishment of a novel fluorescence-based colony quantification. From the metabolite analysis, more lactate was consumed when LGG is co-cultured with EcN; thus, YkgG was further explored as it was foreseen to be the enzyme responsible for lactate conversion to pyruvate. The YkgG enzyme from EcN has V max of 64.5 mM min -1 and catalytic ability k cat /K m of 2055 mM -1 min -1 , that is 6-fold compared to E. coli MG1655. Co-culture strategy of EcN with LGG in the mimic gastrointestinal tract increased the CFU by 50 % and 40 % within 5 mins and 10 mins, respectively. This practical, feasible, and promising symbiosis system aims to accelerate the application of probiotic in healthy food industries.
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FOOD MICROBIOLOGY
·
2023
·
IF 5.3
Hongchen Zhang,Yujun Zhai,Kewei Chen,Hui Shi
Escherichia coli O157:H7 can recover from sublethally injured (SI) state, which causes threat of foodborne illness . Adhesion plays a key role in the carriage of pathogens in food . In this study, we investigated the adhesion ability of SI and recovered E. coli O157:H7 wildtype and its three pili-deficient mutants (curli, type 1 fimbriae , and type IV pili) on six food-related surfaces. Plate counting was used to determine adhesion population after washing and oscillating the surfaces. Spinach exhibited the stronger adhesion population of E. coli O157:H7 than the other fresh produces (p < 0.05). In addition, at least one key pili dominated adhesion on these surfaces, and curli was always included. The adhesion population and contribution of different types of pili were jointly affected by surface and physiological state. This can be attributed to high hydrophobicity and positive charge density on surface and different expression levels of csgB , fimA , fimC and ppdD in SI and recovered cells. Among glucose, mannose , maltose , fructose, lactose, and sucrose , addition of 0.5% mannose could reduce adhesion of cells at all physiological states on stainless steel. Overall, this research will provide support for controlling adhesion of SI and recovered E. coli O157:H7.
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ADVANCED FUNCTIONAL MATERIALS
·
2022
·Vol. 32
·期 29
·2202887
·
IF 19.924
Congyang Mao,Wanyu Jin,Yiming Xiang,Yizhou Zhu,Jun Wu,Xiangmei Liu,Shuilin Wu,Yufeng Zheng,Kenneth M.C. Cheung,Kelvin Wai Kwok Yeung
Multidrug-resistant (MDR) bacteria are emerging and disseminating rapidly, undoubtedly posing an urgent threat to global public health. One particular concern is that MDR Gram-negative bacteria are immunized to available antibiotics owing to a series of biogenetic effects, including the β-barrel assembly machine (BAM complex) in the outer membrane, MDR efflux pumps, and enzymatic degradation/modification, which are known to induce antibiotic resistance (AbR). Here, this work identifies that the AbR mechanisms of MDR Escherichia coli become compromised and sensitive again to conventional antibiotics, when the temperature of infected tissues is elevated to ≈50 °C in situ. This thought is realized by the microwave-driven poly(lactic- co -glycolic acid) microparticles that may effectively convert electromagnetic radiation to thermal energy. The microwave hyperthermia (MWH) therapy not only interrupts the essential surface-exposed BamA protein of the BAM complex, but also enhances the permeability of the outer membrane and inhibits the action of MDR efflux pumps. MWH also impairs the hydrogen bond interaction between the catalytic residues of bacterial enzymes and functional groups of antibiotic molecules. Lastly, this work demonstrates these combined inhibitors can revitalize the bactericidal effects of conventional antibiotics in MDR Escherichia coli -associated deep tissue infections.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Sumei Yu,Yingnan Wang,Fan Shen,Hua Fang,Yunlong Yu
The extensive use of copper-based fungicides in orchards, especially in vineyards, leads to the accumulation of copper, which has caused growing concern. However, data on the acquisition of antibiotic resistance in opportunistic pathogens under copper-based fungicides are scarce. In this study, we investigated the potential development of antibiotic resistance in Escherichia coli K12 under selective copper hydroxide pressure. The results indicated that copper hydroxide at concentrations of 100 mg/L and 200 mg/L evolved resistance against chloramphenicol and tolerance against tetracycline to 4–8 and 2.00–2.67 times than the initial minimal inhibitory concentrations (MICs), respectively. Whole-genome sequencing analysis showed that the obtained resistant strains carried gene mutations including AcrAB-TolC multidrug efflux pump ( acrB and marR ), outer membrane porin ( evZ ), and another indirect pathways. Furthermore, the expression of multidrug efflux pump genes and oxidative stress-related genes were significantly upregulated, whereas outer membrane porin genes were downregulated. Thus, our results could well explain the emergence of antibiotic resistance and resistance mechanisms selected by copper-based fungicide, and provide a basis for the management of copper-based fungicide in agriculture to avoid the spread of antibiotic resistance.
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ACS Nano
·
2023
·
IF 17.1
Gan Zhang,Zhen Huang,Liwen Hu,Yumeng Wang,Shengliang Deng,Daofeng Liu,Juan Peng,Weihua Lai
Escherichia coli O157:H7 (E. coli O157:H7) has become one of the major threats to public health and food safety. However, the culture method as a gold standard for the detection of E. coli O157:H7 requires laborious operations and a long processing time. Herein, we developed a dual-readout aggregation-induced emission nanoparticle-based lateral flow immunoassay (LFIA) for sensitive detection of E. coli O157:H7 to achieve a qualitative and quantitative assay for satisfying the applications under varying scenarios. 2,3-Bis(4-(bis(4-(tert-butyl)phenyl)amino)phenyl)fumaronitrile (BAPF), an aggregation-induced emission luminogen, was designed to achieve a strong molar extinction coefficient (3.0 × 104 M–1 cm–1) and high quantum yield (33.28%), which was further verified by a large rotation angle and low energy gap. Subsequently, BAPFs were integrated into a nanostructured system to form excellent water-soluble nanoparticles (BAPFNPs) for the detection of E. coli O157:H7 with colorimetric and fluorescent readout. The designed BAPFNPs-based LFIA (BAPFNPs-LFIA) exhibited nearly qualitative ability with gold nanoparticles-LFIA (AuNPs-LFIA) and a 9 times enhancement compared with quantum beads-LFIA (QBs-LFIA) in quantitative aspect. Especially, FL-BAPFNPs-LFIA could detect E. coli O157:H7 earlier than QBs-LFIA and AuNPs-LFIA when samples with low E. coli O157:H7 concentrations were cultured. Overall, the proposed strategy revealed that versatile BAPFNPs have great potential as reporters for dual-readout ability and enhancing detection sensitivity for rapid and accurate pathogenic bacteria assay.
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Frontiers in Bioengineering and Biotechnology
·
2020
·
IF 3.644
Peng Fei,Su Hui-Hui,Ou Xiao-Yang,Ni Zi-Fu,Zong Min-Hua,Lou Wen-Yong
(R)-1-phenyl-1,2-ethanediol is an important synthon for the preparation of β-adrenergic blocking agents. This study identified a (2R,3R)-butanediol dehydrogenase (KgBDH) from Kurthia gibsonii SC0312, which showed high enantioselectivity for production of (R)-1-phenyl-1,2-ethanediol by reduction of 2-hydroxyacetophenone. KgBDH was expressed in a recombinant engineered strain, purified, and characterized. It showed good catalytic activity at pH 6–8 and better stability in alkaline (pH 7.5–8) than an acidic environment (pH 6.0–7.0), providing approximately 73 and 88% of residual activity after 96 h at pH 7.5 and 8.0, respectively. The maximum catalytic activity was obtained at 45°C; nevertheless, poor thermal stability was observed at >30°C. Additionally, the examined metal ions did not activate the catalytic activity of KgBDH. A recombinant Escherichia coli strain coexpressing KgBDH and glucose dehydrogenase (GHD) was constructed and immobilized via entrapment with a mixture of activated carbon and calcium alginate via entrapment. The immobilized cells had 1.8-fold higher catalytic activity than that of cells immobilized by calcium alginate alone. The maximum catalytic activity of the immobilized cells was achieved at pH 7.5, and favorable pH stability was observed at pH 6.0–9.0. Moreover, the immobilized cells showed favorable thermal stability at 25–30°C and better operational stability than free cells, retaining approximately 55% of the initial catalytic activity after four cycles. Finally, 81% yields (195 mM product) and >99% enantiomeric excess (ee) of (R)-1-phenyl-1,2-ethanediol were produced within 12 h through a fed-batch strategy with the immobilized cells (25 mg/ml wet cells) at 35°C and 180 rpm, with a productivity of approximately 54 g/L per day.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 103
·期 21
·8839-8851
·
IF 3.67
Liu Yang,Zhu Lingfeng,Qi Wenpeng,Yu Bo
D- p -hydroxyphenylglycine (D-HPG) functions as an intermediate and has important value in antibiotic industries. The high pollution and costs from chemical processes make biotechnological route for D-HPG highly desirable. Here, a whole-cell transformation process by D-hydantoinase(Hase) and D-carbamoylase(Case) was developed to produce D-HPG from DL-hydroxyphenylhydantoin(DL-HPH) in Escherichia coli . The artificially designed ribosome binding site with strong intensity significantly facilitated the protein expression of limiting step enzyme Case. Next, the cell wall permeability was improved by disturbing the peptidoglycan structure by overproduction of D,D-carboxypeptidases without obviously affecting cell growth, to increase the bioavailability of low soluble hydantoin substrate. By fine-tuning regulation of expression level of D,D-carboxypeptidase DacB, the final production yield of D-HPG increased to 100% with 140 mM DL-HPH substrate under the optimized transformation conditions. This is the first example to enhance bio-productivity of chemicals by cell wall engineering and creates a new vision on biotransformation of sparingly soluble substrates. Additionally, the newly demonstrated ‘hydroxyl occupancy’ phenomenon when Case reacts with hydroxyl substrates provides a referential information for the enzyme engineering in future.
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ANALYST
·
2018
·Vol. 143
·期 17
·4067-4073
·
IF 3.864
Chang Cheng,Lu Yang,Miao Zhong,Wenfang Deng,Yueming Tan,Qingji Xie,Shouzhuo Yao
Herein, Au nanocluster (AuNC)-embedded chitosan (CS) nanocapsules were prepared and used as a novel signal amplification system for the sensitive fluorescence immunoassay of Escherichia coli O157:H7 (E. coli O157:H7). AuNCs were embedded in CS to form AuNCs@CS nanocapsules, where a large number of AuNCs were embedded in each nanocapsule. A rapid, ultrasensitive, and selective method for the fluorescence detection of E. coli O157:H7 was developed by coupling the nanocapsule-amplification strategy with immunological recognition and magnetic separation. Compared with a conventional immunoassay using AuNCs as labels, the fluorescence signals of the proposed immunoassay were greatly amplified, because much more fluorescent AuNCs are linked to each bacterial cell. As a result, a linear range was obtained from 3 to 700 CFU mL−1, with a detection limit of 1 CFU mL−1. This method was successfully used to detect E. coli O157:H7 in drinking water and milk samples.
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