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Deng Y, Zhang C, Lv L, Wang K, Liu F, Zhou Y, Peng Z, Wang B. In situ detection of silk fibroin using a dual recognition strategy with a flexible pressure immunosensor. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:1185-1195. [PMID: 38305686 DOI: 10.1039/d3ay01967e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Silk is a symbol of ancient Chinese civilization that has made an indelible contribution to the development of world civilization. However, because ancient artifacts are often contaminated or degraded, it is difficult to detect the presence of silk therein, and the true origin of silk thus remains a mystery. Therefore, this work presents a flexible pressure immunosensor that was designed based on 3D polypyrrole (PPy) foams for the trace detection of silk fibroin at archaeological sites. Initially, silk fibroin (SF) was conjugated with antibody-functionalized copper oxide nanoparticles (CuO NPs) and carboxylated magnetic beads (MBs) to form a sandwich immune complex. Then, the sandwich immune complex was added to hydrogen peroxide (H2O2) by magnetic separation to catalyse the generation of oxygen (O2), which converted the antigen-antibody specific recognition signal to gas pressure. As the pressure within the device increases, the 3D PPy foam, as the sensing layer resistance was 150 Ω, undergoes extrusion and deformation. This deformation leads to alterations in the foam resistance. The flexible pressure immunosensor can sensitively monitor the change in electrical resistance in the system and quantitatively detect silk fibroin. With optimization, the flexible pressure immunosensor demonstrates a dynamic range of operation spanning from 10 ng mL-1 to 100 μg mL-1, exhibiting a remarkable detection limit of 10.58 ng mL-1 specifically for silk fibroin. Notably, this immunosensor surpasses enzyme-linked immunosorbent assay (ELISA) in terms of superior reproducibility, specificity, and accuracy. Therefore, this application provides a new method and technical support for silk detection.
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Affiliation(s)
- Yefeng Deng
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Chao Zhang
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Lianpeng Lv
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Kun Wang
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Feng Liu
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Yang Zhou
- Key Scientific Research Base of Textile Conservation, State Administration for Cultural Heritage, China National Silk Museum, Hangzhou 310002, China
| | - Zhiqin Peng
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Bing Wang
- School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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Park K, Sung H, Kim MN. Evaluation of the cobas Liat detection test for SARS-CoV-2 and influenza viruses following the emergence of the SARS-CoV-2 Omicron variant. Diagn Microbiol Infect Dis 2023; 105:115891. [PMID: 36738537 PMCID: PMC9810546 DOI: 10.1016/j.diagmicrobio.2023.115891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 11/24/2022] [Accepted: 01/01/2023] [Indexed: 01/05/2023]
Abstract
OBJECTIVES This study assessed the clinical performance of the cobas Liat SARS‑CoV‑2 & Influenza A/B assay (LiatCOVID/flu) for the detection of both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses during the SARS-CoV-2 Omicron outbreak. METHODS Residual nasopharyngeal swab samples (NPS) previously tested with cobas SARS-CoV-2 & Influenza A/B for SARS-CoV-2 and with the Allplex Respiratory Panel 1 for influenza viruses were collected. All samples were submitted to the LiatCOVID/flu assay. RESULTS A total of 1147 samples were collected comprising 167 SARS-CoV-2-positive, 556 SARS-CoV-2-negative, 224 influenza-positive, and 200 influenza-negative cases. The positive percent agreement (PPA)/negative percent agreement (NPA) of LiatCOVID/flu for SARS-CoV-2 and influenza viruses compared to the previously tested methods were 100% of 100% and 99.6% of 100%, respectively. CONCLUSIONS The LiatCOVID/flu assay shows an acceptable performance in the detection of SARS-CoV-2 and influenza viruses using NPS samples.
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Affiliation(s)
- Kuenyoul Park
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea
| | - Heungsup Sung
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
| | - Mi-Na Kim
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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pH-Regulated Strategy and Mechanism of Antibody Orientation on Magnetic Beads for Improving Capture Performance of Staphylococcus Species. Foods 2022; 11:foods11223599. [PMID: 36429188 PMCID: PMC9689862 DOI: 10.3390/foods11223599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/04/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Immunomagnetic beads (IMBs) have been widely used to capture and isolate target pathogens from complex food samples. The orientation of the antibody immobilized on the surface of magnetic beads (MBs) is closely related to the effective recognition with an antigen. We put forward an available strategy to orient the antibody on the surface of MBs by changing the charged amino group ratio of the reactive amino groups at optimal pH value. Quantum dots labeling antigen assay, antigen-binding fragment (Fab) accessibility assay and lysine mimicking were used for the first time to skillfully illustrate the antibody orientation mechanism. This revealed that the positively charged ε-NH2 group of lysine on the Fc relative to the uncharged amino terminus on Fab was preferentially adsorbed on the surface of MBs with a negatively charged group at pH 8.0, resulting in antigen binding sites of antibody fully exposed. This study contributes to the understanding of the antibody orientation on the surface of MBs and the potential application of IMBs in the separation and detection of pathogenic bacteria in food samples.
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Azzam AM, Shenashen MA, Selim MS, Mostafa B, Tawfik A, El-Safty SA. Vancomycin-Loaded Furriness Amino Magnetic Nanospheres for Rapid Detection of Gram-Positive Water Bacterial Contamination. NANOMATERIALS 2022; 12:nano12030510. [PMID: 35159855 PMCID: PMC8839226 DOI: 10.3390/nano12030510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/05/2022] [Accepted: 01/27/2022] [Indexed: 12/21/2022]
Abstract
Bacterial pathogens pose high threat to public health worldwide. Different types of nanomaterials have been synthesized for the rapid detection and elimination of pathogens from environmental samples. However, the selectivity of these materials remains challenging, because target bacterial pathogens commonly exist in complex samples at ultralow concentrations. In this study, we fabricated novel furry amino magnetic poly-L-ornithine (PLO)/amine-poly(ethylene glycol) (PEG)-COOH/vancomycin (VCM) (AM-PPV) nanospheres with high-loading VCM for vehicle tracking and the highly efficient capture of pathogens. The magnetic core was coated with organosilica and functionalized with cilia. The core consisted of PEG/PLO loaded with VCM conjugated to Gram-positive bacterial cell membranes, forming hydrogen bonds with terminal peptides. The characterization of AM-PPV nanospheres revealed an average particle size of 56 nm. The field-emission scanning electron microscopy (FE-SEM) micrographs showed well-controlled spherical AM-PPV nanospheres with an average size of 56 nm. The nanospheres were relatively rough and contained an additional 12.4 nm hydrodynamic layer of PLO/PEG/VCM, which provided additional stability in the suspension. The furry AM-PPV nanospheres exhibited a significant capture efficiency (>90%) and a high selectivity for detecting Bacillus cereus (employed as a model for Gram-positive bacteria) within 15 min, even in the presence of other biocompatible pathogens. Moreover, AM-PPV nanospheres rapidly and accurately detected B. cereus at levels less than 10 CFU/mL. The furry nano-design can potentially satisfy the increasing demand for the rapid and sensitive detection of pathogens in clinical and environmental samples.
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Affiliation(s)
- Ahmed M. Azzam
- National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba-shi 305-0047, Ibaraki-ken, Japan; (A.M.A.); (M.S.S.)
- Environmental Research Department, Theodor Bilharz Research Institute (TBRI), Imbaba, Giza 12411, Egypt;
| | - Mohamed A. Shenashen
- National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba-shi 305-0047, Ibaraki-ken, Japan; (A.M.A.); (M.S.S.)
- Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo 11727, Egypt
- Correspondence: (M.A.S.); (S.A.E.-S.)
| | - Mohamed S. Selim
- National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba-shi 305-0047, Ibaraki-ken, Japan; (A.M.A.); (M.S.S.)
- Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo 11727, Egypt
| | - Bayaumy Mostafa
- Environmental Research Department, Theodor Bilharz Research Institute (TBRI), Imbaba, Giza 12411, Egypt;
| | - Ahmed Tawfik
- Water Pollution Research Department, National Research Centre (NRC), Dokki, Giza 12622, Egypt;
| | - Sherif A. El-Safty
- National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba-shi 305-0047, Ibaraki-ken, Japan; (A.M.A.); (M.S.S.)
- Correspondence: (M.A.S.); (S.A.E.-S.)
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Abstract
Magnetic cell separation has become a key methodology for the isolation of target cell populations from biological suspensions, covering a wide spectrum of applications from diagnosis and therapy in biomedicine to environmental applications or fundamental research in biology. There now exists a great variety of commercially available separation instruments and reagents, which has permitted rapid dissemination of the technology. However, there is still an increasing demand for new tools and protocols which provide improved selectivity, yield and sensitivity of the separation process while reducing cost and providing a faster response. This review aims to introduce basic principles of magnetic cell separation for the neophyte, while giving an overview of recent research in the field, from the development of new cell labeling strategies to the design of integrated microfluidic cell sorters and of point-of-care platforms combining cell selection, capture, and downstream detection. Finally, we focus on clinical, industrial and environmental applications where magnetic cell separation strategies are amongst the most promising techniques to address the challenges of isolating rare cells.
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Gunasekaran D, Gerchman Y, Vernick S. Electrochemical Detection of Waterborne Bacteria Using Bi-Functional Magnetic Nanoparticle Conjugates. BIOSENSORS 2022; 12:bios12010036. [PMID: 35049664 PMCID: PMC8774000 DOI: 10.3390/bios12010036] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 05/05/2023]
Abstract
Detection of microbial contamination in water is imperative to ensure water quality. We have developed an electrochemical method for the detection of E. coli using bi-functional magnetic nanoparticle (MNP) conjugates. The bi-functional MNP conjugates were prepared by terminal-specific conjugation of anti-E. coli IgG antibody and the electroactive marker ferrocene. The bi-functional MNP conjugate possesses both E. coli-specific binding and electroactive properties, which were studied in detail. The conjugation efficiency of ferrocene and IgG antibodies with amine-functionalized MNPs was investigated. Square-wave voltammetry enabled the detection of E. coli concentrations ranging from 101-107 cells/mL in a dose-dependent manner, as ferrocene-specific current signals were inversely dependent on E. coli concentrations, completely suppressed at concentrations higher than 107 cells/mL. The developed electrochemical method is highly sensitive (10 cells/mL) and, coupled to magnetic separation, provides specific signals within 1h. Overall, the bi-functional conjugates serve as ideal candidates for electrochemical detection of waterborne bacteria. This approach can be applied for the detection of other bacteria and viruses.
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Affiliation(s)
- Dharanivasan Gunasekaran
- Department of Sensing, Information and Mechanization Engineering, Institute of Agricultural Engineering, Volcani Institute (ARO), Rishon leZion 5025001, Israel;
| | - Yoram Gerchman
- The Faculty of Natural Sciences, Oranim Academic College of Education, The University of Haifa, Tivon 3600600, Israel;
| | - Sefi Vernick
- Department of Sensing, Information and Mechanization Engineering, Institute of Agricultural Engineering, Volcani Institute (ARO), Rishon leZion 5025001, Israel;
- Correspondence: ; Tel.: +972-3-968-3499
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7
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Bai Y, Cui Y, Suo Y, Shi C, Wang D, Shi X. A Rapid Method for Detection of Salmonella in Milk Based on Extraction of mRNA Using Magnetic Capture Probes and RT-qPCR. Front Microbiol 2019; 10:770. [PMID: 31024515 PMCID: PMC6459957 DOI: 10.3389/fmicb.2019.00770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 03/26/2019] [Indexed: 11/17/2022] Open
Abstract
Magnetic separation is an efficient method for target enrichment and elimination of inhibitors in the molecular detection systems for foodborne pathogens. In this study, we prepared magnetic capture probes by modifying oligonucleotides complementary to target sequences on the surface of amino-modified silica-coated magnetic nanoparticles and optimized the conditions and parameters of probe synthesis and hybridization. We innovatively put the complexes of magnetic capture probes and target sequences into qPCR without any need for denaturation and purification steps. This strategy can reduce manual steps and save time. We used the magnetic capture probes to separate invA mRNA from Salmonella in artificially contaminated milk samples. The detection sensitivity was 104 CFU/ml, which could be increased to 10 CFU/ml after a 12 h enrichment step. The developed method is robust enough to detect live bacteria in a complex environmental matrix.
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Affiliation(s)
- Yalong Bai
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China.,Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Yan Cui
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Yujuan Suo
- Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Chunlei Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Dapeng Wang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xianming Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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Kim JH, Yoo JG, Ham JS, Oh MH. Direct Detection of Escherichia coli, Staphylococcus aureus, and Salmonella spp. in Animal-derived Foods Using a Magnetic Bead-based Immunoassay. Korean J Food Sci Anim Resour 2018; 38:727-736. [PMID: 30206432 PMCID: PMC6131368 DOI: 10.5851/kosfa.2018.e11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/21/2018] [Accepted: 07/01/2018] [Indexed: 01/10/2023] Open
Abstract
In this study, an immuno-magnetic bead (IMB)-based assay was developed to simultaneously detect Escherichia coli, Staphylococcus aureus, and Salmonella spp. and was tested in four animal-derived foods: beef, ham, egg, and ricotta cheese. The IMB-based assay exhibited good specificity by binding to five E. coli serotypes [capture efficiency (CE) average (avg.) 90.4%], five S. aureus strains (CE avg. 91.4%), and five Salmonella serotypes (CE avg. 95.4%) but not binding to non-target bacteria (CE<10%). Furthermore, the assay detected all three pathogens with a detection limit of 10 CFU/g without the need for enrichment or additional platforms. Since the results demonstrated that the IMB-based assay can effectively separate and enrich target bacteria from a variety of animal-derived food matrixes, the assay exhibits good specificity for potential use in providing rapid, immunological, presumptive identification of pathogenic bacteria.
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Affiliation(s)
| | | | | | - Mi-Hwa Oh
- National Institute of Animal Science, Rural Development
Administration, Wanju 55365, Korea
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Characterization of a novel plasmid encoding F4-like fimbriae present in a Shiga-toxin producing enterotoxigenic Escherichia coli isolated during the investigation on a case of hemolytic-uremic syndrome. Int J Med Microbiol 2018; 308:947-955. [PMID: 30030028 DOI: 10.1016/j.ijmm.2018.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 11/21/2022] Open
Abstract
In February 2017 a case of Hemolytic-Uremic Syndrome (HUS) was reported to the National Registry of HUS in an adult living in Northern Italy. Stool specimens from the patient and his family contacts were collected and the analyses led to the isolation of a Locus of Enterocyte Effacement (LEE)-negative Shiga toxin 2 (Stx2)-producing Escherichia coli. The epidemiological investigations performed brought to collect fecal samples from the animals reared in a farm held by the case's family and a mixture of bovine and swine feces proved positive for Shiga toxin-producing E. coli (STEC) and yielded the isolation of a LEE-negative stx2-positive E. coli strain. Further characterization by whole genome sequencing led to identify the isolates as two identical O2:H27 hybrid Enterotoxigenic Shiga toxin-producing E. coli (ETEC-STEC). Sequencing of a high molecular weight plasmid present in the human isolate disclosed a peculiar plasmid harboring virulence genes characteristic for both pathotypes, including the enterohemolysin-coding gene and sta1, encoding the heat stable enterotoxin. Moreover, a complete fae locus encoding the ETEC F4 fimbriae could be identified, including a novel variant of faeG gene responsible for the production of the main structural subunit of the fimbriae. This novel faeG showed great diversity in the nucleotidic sequence when compared with the reference genes encoding the swine F4 allelic variants, whereas at the amino acid sequence level the predicted protein sequence showed some similarity with FaeG from E. coli strains of bovine origin. Further investigation on the plasmid region harboring the newly identified faeG allelic variant allowed to identify similar plasmids in NCBI sequence database, as part of the genome of other previously uncharacterized ETEC-STEC strains of bovine origin, suggesting that the novel F4-like fimbriae may play a role in bovine host specificity.
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Nishino T, Matsuda Y, Yamazaki Y. Separation of viable lactic acid bacteria from fermented milk. Heliyon 2018; 4:e00597. [PMID: 29862359 PMCID: PMC5968145 DOI: 10.1016/j.heliyon.2018.e00597] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/06/2018] [Accepted: 04/03/2018] [Indexed: 11/16/2022] Open
Abstract
Probiotics are live microorganisms that provide health benefits to humans. Some lactic acid bacteria (LAB) are probiotic organisms used in the production of fermented foods, such as yogurt, cheese, and pickles. Given their widespread consumption, it is important to understand the physiological state of LAB in foods such as yogurt. However, this analysis is complicated, as it is difficult to separate the LAB from milk components such as solid curds, which prevent cell separation by dilution or centrifugation. In this study, we successfully separated viable LAB from yogurt by density gradient centrifugation. The recovery rate was >90 %, and separation was performed until the stationary phase. Recovered cells were observable by microscopy, meaning that morphological changes and cell viability could be directly detected at the single-cell level. The results indicate that viable LAB can be easily purified from fermented milk. We expect that this method will be a useful tool for the analysis of various aspects of probiotic cells, including their enzyme activity and protein expression.
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Affiliation(s)
- Tomohiko Nishino
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404 Katakura, Hachioji, Tokyo, 192-0982, Japan
| | - Yusuke Matsuda
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404 Katakura, Hachioji, Tokyo, 192-0982, Japan
| | - Yuna Yamazaki
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404 Katakura, Hachioji, Tokyo, 192-0982, Japan
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Serroni A, Magistrali CF, Pezzotti G, Bano L, Pellegrini M, Severi G, Di Pancrazio C, Luciani M, Tittarelli M, Tofani S, De Giuseppe A. Expression of deleted, atoxic atypical recombinant beta2 toxin in a baculovirus system and production of polyclonal and monoclonal antibodies. Microb Cell Fact 2017; 16:94. [PMID: 28545467 PMCID: PMC5445335 DOI: 10.1186/s12934-017-0707-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/16/2017] [Indexed: 11/25/2022] Open
Abstract
Background Clostridium perfringens is an important animal and human pathogen that can produce more than 16 different major and minor toxins. The beta-2 minor toxin (CPB2), comprising atypical and consensus variants, appears to be involved in both human and animal enterotoxaemia syndrome. The exact role of CPB2 in pathogenesis is poorly investigated, and its mechanism of action at the molecular level is still unknown because of the lack of specific reagents such as monoclonal antibodies against the CPB2 protein and/or the availability of a highly purified antigen. Previous studies have reported that purified wild-type or recombinant CPB2 toxin, expressed in a heterologous system, presented cytotoxic effects on human intestinal cell lines. Undoubtedly, for this reason, to date, these purified proteins have not yet been used for the production of monoclonal antibodies (MAbs). Recently, monoclonal antibodies against CPB2 were generated using peptides designed on predicted antigenic epitopes of this toxin. Results In this paper we report, for the first time, the expression in a baculovirus system of a deleted recombinant C-terminal 6xHis-tagged atypical CPB2 toxin (rCPB2Δ1–25-His6) lacking the 25 amino acids (aa) of the N-terminal putative signal sequence. A high level of purified recombinant rCPB2Δ1–25-His6 was obtained after purification by Ni2+ affinity chromatography. The purified product showed no in vitro and in vivo toxicity. Polyclonal antibodies and twenty hybridoma-secreting Mabs were generated using purified rCPB2Δ1–25-His6. Finally, the reactivity and specificity of the new antibodies were tested against both recombinant and wild-type CPB2 toxins. Conclusions The high-throughput of purified atoxic recombinant CPB2 produced in insect cells, allowed to obtain monoclonal and polyclonal antibodies. The availability of these molecules could contribute to develop immunoenzymatic methods and/or to perform studies about the biological activity of CPB2 toxin.
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Affiliation(s)
- Anna Serroni
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy.,Scuola di Specializzazione "Biochimica Clinica" G. d'Annunzio, University Chieti-Pescara, Chieti, Italy
| | | | - Giovanni Pezzotti
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy
| | - Luca Bano
- Istituto Zooprofilattico Sperimentale delle Venezie, Vicolo Mazzini 4, Villorba Di Treviso, Italy
| | - Martina Pellegrini
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy
| | - Giulio Severi
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy
| | - Chiara Di Pancrazio
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G.Caporale", Teramo, Italy
| | - Mirella Luciani
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G.Caporale", Teramo, Italy
| | - Manuela Tittarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G.Caporale", Teramo, Italy
| | - Silvia Tofani
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy
| | - Antonio De Giuseppe
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Via G. Salvemini 1, 06126, Perugia, Italy.
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12
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Burlage RS, Tillmann J. Biosensors of bacterial cells. J Microbiol Methods 2016; 138:2-11. [PMID: 28040457 DOI: 10.1016/j.mimet.2016.12.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/24/2016] [Accepted: 12/24/2016] [Indexed: 10/20/2022]
Abstract
Biosensors are devices which utilize both an electrical component (transducer) and a biological component to study an environment. They are typically used to examine biological structures, organisms and processes. The field of biosensors has now become so large and varied that the technology can often seem impenetrable. Yet the principles which underlie the technology are uncomplicated, even if the details of the mechanisms are elusive. In this review we confine our analysis to relatively current advancements in biosensors for the detection of whole bacterial cells. This includes biosensors which rely on an added labeled component and biosensors which do not have a labeled component and instead detect the binding event or bound structure on the transducer. Methods to concentrate the bacteria prior to biosensor analysis are also described. The variety of biosensor types and their actual and potential uses are described.
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Affiliation(s)
- Robert S Burlage
- Department of Pharmaceutical and Administrative Science, Concordia University School of Pharmacy, 12800 N. Lake Shore Dr., Mequon, WI 53097, United States.
| | - Joshua Tillmann
- Department of Pharmaceutical and Administrative Science, Concordia University School of Pharmacy, 12800 N. Lake Shore Dr., Mequon, WI 53097, United States
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13
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Yang X, Zhou X, Zhu M, Xing D. Sensitive detection of Listeria monocytogenes based on highly efficient enrichment with vancomycin-conjugated brush-like magnetic nano-platforms. Biosens Bioelectron 2016; 91:238-245. [PMID: 28013018 DOI: 10.1016/j.bios.2016.11.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 10/26/2016] [Accepted: 11/10/2016] [Indexed: 10/20/2022]
Abstract
Pathogens pose a significant threat to public health worldwide. Despite many technological advances in the rapid diagnosis of pathogens, sensitive pathogen detection remains challenging because target pathogenic bacteria usually exist in complex samples at very low concentrations. Here, the construction of multivalent brush-like magnetic nanoprobes and their application for the efficient enriching of pathogens are demonstrated. Brush-like magnetic nanoprobes were constructed by modification with poly-L-lysine (PLL) onto amino-modified magnetic beads, followed by coupling of PEG (amine-PEG5000-COOH) to the amine sites of PLL. Subsequently, vancomycin (Van), a small-molecule antibiotic with affinity to the terminal peptide (D-alanyl-D-alanine) on the cell wall of Gram-positive bacteria, was conjugated to the carboxyl of the PEG. The use of multivalent brush-like magnetic nanoprobes (Van-PEG-PLL-MNPs) results in a high enrichment efficiency (>94%) and satisfactory purity for Listeria monocytogenes (employed as a model) within 20min, even at bacterial concentrations of only 102cfumL-1. Integrated with the enrichment of the Van-PEG-PLL-MNP nano-platform and electrochemiluminescence (ECL) detection, Listeria monocytogenes can be rapidly and accurately detected at levels as low as 10cfumL-1. The approach described herein holds great potential for realizing rapid and sensitive pathogen detection in clinical samples.
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Affiliation(s)
- Xiaoke Yang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Xiaoming Zhou
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
| | - Minjun Zhu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
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