KEY ENGINEERING MATERIALS
·
2019
·
IF 0
Xiao Zhan Yang,Wen Lin Feng,Gao Chen,Hong Feng Guo,Dao Yuan Wang
Escherichia coli O157: H7 (E. coli O157: H7) is a foodborne pathogenic bacterium which can cause fever, diarrhoea and vomiting in humans. Thus, a rapid, simple, and specific bioprobe for pathogen detection in contaminated foods has been attracted more and more attention. In this work, the strong fluorescent amino-functionalized graphene quantum dots (af-GQDs) were prepared by hydrothermal method. The microtopographic height, surface morphology and spectroscopic properties of af-GQDs are characterized by the high resolution transmission electron microscope (HRTEM), atomic force microscope (AFM), UV-vis, fluorescence, Raman spectroscopic techniques. All the results showed that the af-GQDs can be effectively applied in the preparation of biocompatible immunofluorescence probe and in the detection of E. coli O157: H7. The minimum detection limit is 100 cfu/mL. It is a simple, rapid, sensitive, low-cost and easy to be popularized method, which provides a feasible way to monitor E. coli O157: H7 in food safety.
✓ 已验证
产品关联
DOI
RSC Advances
·
2018
·Vol. 8
·期 53
·30512-30519
·
IF 2.936
Jian-Xiu Li,Yan-Yan Huang,Xian-Rui Chen,Qi-Shi Du,Jian-Zong Meng,Neng-Zhong Xie,Ri-Bo Huang
Acetoin is an important platform chemical with a variety of applications in foods, cosmetics, chemical synthesis, and especially in the asymmetric synthesis of optically active pharmaceuticals. It is also a useful breath biomarker for early lung cancer diagnosis. In order to enhance production of optical (S)-acetoin and facilitate this building block for a series of chiral pharmaceuticals derivatives, we have developed a systematic approach using in situ-NADH regeneration systems and promising diacetyl reductase. Under optimal conditions, we have obtained 52.9 g L−1 of (S)-acetoin with an enantiomeric purity of 99.5% and a productivity of 6.2 g (L h)−1. The results reported in this study demonstrated that the production of (S)-acetoin could be effectively improved through the engineering of cofactor regeneration with promising diacetyl reductase. The systematic approach developed in this study could also be applied to synthesize other optically active α-hydroxy ketones, which may provide valuable benefits for the study of drug development.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Jiang Huang,Zhiyang Huang,Guangran Ma,Fugang Xu,Hongliang Tan
Ensuring the reliable and accurate detection of Escherichia coli ( E. coli ) is essential for maintaining food safety and safeguarding human health. In this work, a dual-mode sensor that integrates colorimetric and fluorescence detection was developed for the precise identification of E. coli . Fe 3 O 4 nanoparticles (NPs) were coated with a fluorescein-labeled aptamer (FAM-Apt) to enhance their peroxidase-like activity under neutral pH conditions. Simultaneously, this coating also effectively suppressed the fluorescence emitted by FAM. Upon exposure to E. coli , specific binding of the bacteria causes the detachment of FAM-Apt from the Fe 3 O 4 NPs surface, resulting in the suppression of Fe 3 O 4 NPs catalytic activity under neutral pH and the alleviation of the quenching effect on FAM fluorescence. This leads to a simultaneous decrease in the colorimetric signal and an increase in fluorescence signal, facilitating the development of a dual-mode detection method for E. coli with an impressive limit of detection (LOD) of 10 CFU/mL in the colorimetric mode and 6 CFU/mL in the fluorescence mode. This approach highlights the untapped potential of Fe 3 O 4 NPs as a peroxidase mimic in dual-mode sensors, offering a promising strategy for E. coli detection with significant implications for enhancing food safety and public health practices.
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2024
·
IF 5.3
Xingxing Jiang,Aomei Zhang,Huan Gou,Xiang Chen,Lei Deng,Minghui Yang
Highly pathogenic bacterial infections are a major threat to human health, and the resulting drug resistance is beginning to pose a major clinical threat. To combat multidrug-resistant bacterial infections, there is an urgent need to develop antimicrobial drugs that are highly effective, environmentally friendly, and able to prevent the emergence of bacterial resistance. In this paper, Co4N nanozymes were successfully synthesized by pyrolysis of a presynthesized Co-containing metal organic framework (Co-MOF). Its peroxide and lactate oxidase activity and antimicrobial properties were investigated. Without the addition of exogenous H2O2, the nanozymes can initially generate H2O2 by catalyzing lactic acid and then produce highly active •OH from H2O2. This approach overcomes the obstacle of insufficient H2O2 to achieve a satisfactory antimicrobial effect. Furthermore, the local high temperature generated by Co4N under 808 nm laser irradiation further enhanced the antibacterial effect. These results showed that the nanozyme possesses broad-spectrum antimicrobial activity against Escherichia coli and Staphylococcus aureus, with an inhibition rate as high as 99% within 2 h. Meanwhile, the enzyme has good biocompatibility, paving a way for the application of MOF materials in biomedical fields.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Jingran Zhang,Zihan Yuan,Chao Wang,Lele Liu,Yanan Wang,Yurong Guo,Guangjiu Zhao
Perovskite nanocrystals (PNCs) have attracted extensive attention for their potential applications in biology. However, only a handful of PNCs have been scrutinized in the biological domain due to issues such as instability, poor dispersion, and size inhomogeneity in polar solvents. The development of dual-functional perovskite nanomaterials with hydrogen sulfide (H 2 S) sensing and antibacterial capabilities is particularly intriguing. In this study, we prepared chiral quasi-two-dimensional (quasi-2D) perovskite nanomaterials, Bio(S-PEA) 2 CsPb 2 Br 7 and Bio(R-PEA) 2 CsPb 2 Br 7 , that were uniformly dispersed in aqueous media. The effective encapsulation of methoxypolyethylene glycol amine (mPEG-NH 2 ) improved water stability and uniformity of particle size. Circular dichroism (CD) signals were created by the successful insertion of chiral cations. These perovskites as probes showed a rapid and sensitive fluorescence quenching response to H 2 S, and the effect of imaging detection was observed at the Escherichia coli (E. coli) level. As antibacterial agents, their pronounced positive charge properties facilitated membrane lysis and subsequent E. coli death, indicating a significant antibacterial effect. This work has preliminary explored the application of chiral perovskites in biology and provides insight into the development of bifunctional perovskite nanomaterials for biological applications.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF DAIRY SCIENCE
·
2017
·
IF 2.474
Kai Luo,Liming Hu,Qi Guo,Chenghui Wu,Songsong Wu,Daofeng Liu,Yonghua Xiong,Weihua Lai
ABSTRACT Immunochromatographic assays (ICA) are widely used to detect pathogens. In this study, we used traditional gold nanoparticles (GNP), quantum dots (QD), fluorescent nanoparticles (FNP), and europium (Eu) (III) chelate nanoparticles (EuNP) as ICA labels. We first compared the ability of the 4 ICA test strips to quantitatively detect Escherichia coli O157:H7 in milk. We then optimized various parameters influencing the ICA. The sensitivity to E. coli O157:H7 of the GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA was 2.5 × 10 4 , 5 × 10 3 , 1.0 × 10 3 , and 5.0 × 10 2 cfu mL −1 , respectively. The EuNP-ICA exhibited the highest sensitivity. The amounts of monoclonal antibodies (mAb) per GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA test strip were 0.16, 0.37, 0.04, and 0.10 μg, respectively. The corresponding coefficients of variation were 7.4 to 15.8%, 10.4 to 18.6%, 2.7 to 7.8%, and 6.9 to 10.5%, respectively. The FNP-ICA required the least mAb per test strip and had the best coefficient of variation. The linear ranges of GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA were 1.0 × 10 4 to 1.0 × 10 6 , 2.5 × 10 3 to 1.0 × 10 6 , 2.5 × 10 2 to 2.5 × 10 5 , and 2.5 × 10 2 to 2.5 × 10 5 cfu mL −1 , respectively. The FNP-ICA and EuNP-ICA had wider linear ranges than GNP-ICA and QD-ICA. Additionally, the FNP-ICA and EuNP-ICA showed better tolerance than GNP-ICA and QD-ICA in the milk samples. The FNP-ICA and EuNP-ICA showed remarkable potential for detection of pathogens in milk.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PLoS One
·
2015
·Vol. 10
·期 8
·e0136450
·
IF 3.234
Guyue Cheng,Bei Li,Chenxi Wang,Hongfei Zhang,Guixia Liang,Zhifei Weng,Haihong Hao,Xu Wang,Zhenli Liu,Menghong Dai,Yulian Wang,Zonghui Yuan
Quinoxaline 1,4-di- N -oxides (QdNOs) are widely known as potent antibacterial agents, but their antibacterial mechanisms are incompletely understood. In this study, the transcriptomic and proteomic profiles of Esch erichia coli exposed to QdNOs were integratively investigated, and the results demonstrated that QdNOs mainly induced an SOS response and oxidative stress. Moreover, genes and proteins involved in the bacterial metabolism, cellular structure maintenance, resistance and virulence were also found to be changed, conferring bacterial survival strategies. Biochemical assays showed that reactive oxygen species were induced in the QdNO-treated bacteria and that free radical scavengers attenuated the antibacterial action of QdNOs and DNA damage, suggesting an oxidative-DNA-damage action of QdNOs. The QdNO radical intermediates, likely carbon-centered and aryl-type radicals, as identified by electron paramagnetic resonance, were the major radicals induced by QdNOs, and xanthine oxidase was one of the QdNO-activating enzymes. This study provides new insights into the action of QdNOs in a systematic manner and increases the current knowledge of bacterial physiology under antibiotic stresses, which may be of great value in the development of new antibiotic-potentiating strategies.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biotechnology Journal
·
2015
·Vol. 11
·期 2
·228-237
·
IF 3.49
Tian Ma,Yuanjie Zhou,Xiaowei Li,Fayin Zhu,Yongbo Cheng,Yi Liu,Zixin Deng,Tiangang Liu
As a highly valued keto-carotenoid, astaxanthin is widely used in nutritional supplements and pharmaceuticals. Therefore, the demand for biosynthetic astaxanthin and improved efficiency of astaxanthin biosynthesis has driven the investigation of metabolic engineering of native astaxanthin producers and heterologous hosts. However, microbial resources for astaxanthin are limited. In this study, we found that the α-Proteobacterium Sphingomonas sp. ATCC 55669 could produce astaxanthin naturally. We used whole-genome sequencing to identify the astaxanthin biosynthetic pathway using a combined PacBio-Illumina approach. The putative astaxanthin biosynthetic pathway in Sphingomonas sp. ATCC 55669 was predicted. For further confirmation, a high-efficiency targeted engineering carotenoid synthesis platform was constructed in E. coli for identifying the functional roles of candidate genes. All genes involved in astaxanthin biosynthesis showed discrete distributions on the chromosome. Moreover, the overexpression of exogenous E. coli idi in Sphingomonas sp. ATCC 55669 increased astaxanthin production by 5.4-fold. This study described a new astaxanthin producer and provided more biosynthesis components for bioengineering of astaxanthin in the future. Graphical Limited microbial resources for astaxanthin limit its widespread applications in nutritional supplements and pharmaceuticals. Sphingomonas sp. ATCC 55669 can produce astaxanthin naturally. Whole-genome sequencing with gene functional confirmation identifies the discrete astaxanthin biosynthetic genes, and overexpressed related genes in E. coli can increase astaxanthin production. The new astaxanthin producer and biosynthesis components provide more possibilities for bioengineering of astaxanthin in the future.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
·
2017
·
IF 3.339
Xiaobing Jiang,Yameng Xu,Yi Li,Kun Zhang,Lei Liu,Hailei Wang,Jinhe Tian,Hao Ying,Lei Shi,Tao Yu
The aim of this study was to examine the presence of genes responsible for resistance to quaternary ammonium compounds (QACs) and the association of qac genes with class 1 integrons in Escherichia coli isolated from retail meats. Among the 179 E. coli isolates tested, the minimum inhibitory concentrations (MICs) of benzalkonium chloride (BC) ranged from 4 to 64 μg/mL. PCR assays indicated that QAC-resistance genes sugE(c) , ydgE / ydgF , mdfA , emrE and qacE Δ1 were commonly present (40.2%–88.3%) in these isolates, but qacE , qacF , qacH and sugE(p) were less prevalent (2.2%–28.5%). Seven different gene cassette arrangements were identified in 31 intI1 -positive isolates. Three types of qacH-sul3 -associated non-classic integrons were observed in four isolates: dfrA12 - orfF - aadA2-cmlA1-aadA1-qacH- IS 440-sul3 , aadA2-cmlA1-aadA1-qacH- IS 440-sul3 and dfrA1-aadA1-qacH- IS 440-sul3 . Non-classic class 1 integrons were located on plasmids of 100–150 kb in these four isolates. Our results demonstrated that the qacH -associated integrons located on 100 kb plasmids in two isolates could be transferred to an E. coli recipient, indicating the co-existence and co-dissemination of disinfectant and antimicrobial resistance genes among bacterial species.
✓ 已验证
DOI
PubMed
高影响因子
Food Bioscience
·
2025
·
IF 5.9
Cheng-Hai Yan,Ding Wang,Ruo-Xi Mei,Lu Tan,Yi-Jiang-Cheng Li,Richard Ansah Herman,Yan Xu,Lu-Chan Gong,Jun Wang
Natural flavonoids exhibit diverse physiological effects and are used as functional factors, antioxidants and pigments in food as well as pharmaceutical and cosmetic applications. However, their poor solubility and stability, result in low bioavailability. Biomodification through deglycosylation effectively enhances their bioactivity. This study developed two surface display strategies in Escherichia coli , anchoring α -L-rhamnosidase RhaB1-ΔN to the cell surface using the anchoring protein Lpp-OmpA. Immunofluorescence and proteinase K sensitivity tests confirmed the successful construction of surface-displaying strains E. coli Lpp-OmpA-RhaB1-ΔN and E. coli RhaB1-ΔN-SpyCatcher-SpyTag. Enzymatic property studies revealed improved temperature and pH stability of the whole-cell catalysts with surface compared to free enzymes. After 6 catalytic cycles, E. coli Lpp-OmpA-RhaB1-ΔN retained higher activity than E. coli RhaB1-ΔN. In flavonoid hydrolysis, E. coli Lpp-OmpA-RhaB1-ΔN increased yields of isoquercitrin and kaempferol-3- O -glucuronide by 20.25% and 10.99%, respectively, compared with that in whole-cell catalyst with intracellular enzyme ( p < 0.05). In addition, it should be noted that although the enzyme expression of E. coli RhaB1-ΔN-SpyCatcher-SpyTag is reduced, its hydrolysis ability of flavonoids is comparable to that of E. coli RhaB1-ΔN due to the efficient catalytic ability of extracellular enzymes. This study establishes reliable whole-cell catalysts with surface-displayed α -L-rhamnosidase for efficient natural flavonoid modification, with potential applications in the food and pharmaceutical industries.
✓ 已验证
产品关联
DOI
高影响因子
COMPUTERS AND ELECTRONICS IN AGRICULTURE
·
2025
·
IF 8.9
Zhuangzhuang Bai,Bingxiong Wang,Tingyao Gao,Xianbao Xu,Zhuangzhuang Du,Jie Han,Yang Hu,Yu Bai,Liu Wang,Cong Wang,Daoliang Li
The on-site and real-time detection of pathogenic bacteria under the aquaponics production process is critical for controlling diseases of aquatic products and ensuring food safety of agricultural products. In this study, a novel microfluidic colorimetric biosensor was developed for rapid, sensitive and automated detection of the widespread foodborne and waterborne pathogen, Escherichia coli O157:H7 ( E. coli O157:H7). Firstly, immune magnetic nanoparticles (MNPs), samples and immune platinum nanoparticles (Pt NPs) were mixed and incubated in “pearl chain” micromixers forming MNP-bacteria-Pt NP sandwich complexes. Then, a mixture of 3,3′,5,5′-tetramethylbenzidine (TMB) and hydrogen peroxide (H 2 O 2 ) was injected and catalyzed by Pt NPs to produce blue oxidized TMB (oxTMB). Finally, colorimetric analysis of the catalytic substrate was performed to determine the target bacterial concentration using an improved AS7265x spectral sensor. As shown in the experimental results, this biosensor was able to detect E. coli O157:H7 at 5 × 10 1 ∼ 5 × 10 6 CFU/mL within 45 min with the lower detection limit of 17 CFU/mL. Notably, the biosensor is a universal detection platform that allows for the detection of other pathogenic bacteria in aquaponics water via the replacement of the biometric element.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）