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Sun X, Song G, Hu Z, Zhang W, Luo N, Gao H. An electrochemical immunosensor based on hybrid self-assembled monolayers for rapid detection of Bombyx mori nucleopolyhedrovirus. J Invertebr Pathol 2024; 204:108080. [PMID: 38432354 DOI: 10.1016/j.jip.2024.108080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/05/2024]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is highly contagious and poses a serious threat to sericulture production. Because there are currently no effective treatments for BmNPV, a rapid and simple detection method is urgently needed. This paper describes an electrochemical immunosensor for the detection of BmNPV. The immunosensor was fabricated by covalently immobilizing anti-BmNPV, a biorecognition element, onto the surface of the working gold electrode via 11-mercaptoundecanoic acid (MUA)/β-mercaptoethanol (ME) hybrid self-assembled monolayers. Electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) were used to characterize the electrochemical performance and morphology of the immunosensor, respectively. Under optimum conditions, the developed immunosensor exhibited a linear response to BmNPV polyhedrin in the range of 1 × 102-1 × 108 fg/mL, with a low detection limit of 14.54 fg/mL. The immunosensor also exhibited remarkable repeatability, reproducibility, specificity, accuracy, and regeneration. Normal silkworm blood was mixed with BmNPV polyhedrin and analyzed quantitatively using this sensor, and the recovery was 92.31 %-100.61 %. Additionally, the sensor was used to analyze silkworm blood samples at different time points after BmNPV infection, and an obvious antigen signal was detected at 12 h post infection. Although this result agreed with that provided by the conventional polymerase chain reaction (PCR) method, the electroanalysis method established in this study was simpler, shorter in detection period, and lower in material cost. Furthermore, this innovative electrochemical immunosensor, developed for the ultra-sensitive and rapid detection of BmNPV, can be used for the early detection of virus-infected silkworms.
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Affiliation(s)
- Xiaomei Sun
- College of Forestry, Shandong Agricultural University, Taian 271018, China
| | - Guizhen Song
- College of Forestry, Shandong Agricultural University, Taian 271018, China
| | - Zengjuan Hu
- Qingdao Agricultural Technology Extension Center, Qingdao 266100, China
| | - Wenjing Zhang
- College of Forestry, Shandong Agricultural University, Taian 271018, China
| | - Ning Luo
- College of Forestry, Shandong Agricultural University, Taian 271018, China
| | - Huiju Gao
- College of Forestry, Shandong Agricultural University, Taian 271018, China; State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, Shandong Agricultural University, Taian 271018, China.
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Ren F, Yan J, Kontogiannatos D, Wang X, Li J, Swevers L, Sun J. Characterization of virus-like particles assembled by co-expression of BmCPV capsid shell protein and large protrusion protein. Int J Biol Macromol 2022; 209:1656-1664. [PMID: 35460752 DOI: 10.1016/j.ijbiomac.2022.04.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/09/2022] [Accepted: 04/13/2022] [Indexed: 11/18/2022]
Abstract
Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) is a typical single-layer capsid dsRNA virus belonging to the Reoviridae family of the Cypovirus genus. Previous studies have shown that the BmCPV major capsid shell protein (CSP) has the ability to self-assemble into virus-like particles (VLPs), and cryo-electron microscopy of the BmCPV virions has revealed a tight mutual binding region between CSP and another capsid protein known as the Large Protrusion Protein (LPP), which further stabilizes the capsid shell. In this study, the multi-gene baculovirus expression system, Ac-MultiBac, was used to produce both solely CSP-based and CSP-LPP co-assembled VLPs. Transmission electron microscopy (TEM) results showed that addition of LPP did not affect the assembly of VLPs resulting in almost identical structure in both cases. However, ex vivo administration of VLPs to silkworm midgut tissue showed that CSP-based VLPs did not induce a significant transcriptional response in the innate immunity and RNAi gene cascades, compared to the co-assembled CSP-LPP based VLPs and the natural BmCPV virions isolated from polyhedra. The experimental results indicate that CSP and LPP attach tightly ("Plug and Display" model with CSP acting as "catcher" and LPP as "tag") to form VLPs that have a structure similar to that of the native CPV virions. Moreover, our results showed that the formation of VLPs with the two BmCPV capsid proteins is feasible, which can form the basis for the production of BmCPV-based VLPs as a new type of biological material to display exogenous proteins.
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Affiliation(s)
- Feifei Ren
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jiming Yan
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Dimitrios Kontogiannatos
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Aghia Paraskevi, Athens 15341, Greece
| | - Xiong Wang
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jingyang Li
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Aghia Paraskevi, Athens 15341, Greece.
| | - Jingchen Sun
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
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Ren F, Swevers L, Lu Q, Zhao Y, Yan J, Li H, Sun J. Effect of mutations in capsid shell protein on the assembly of BmCPV virus-like particles. J Gen Virol 2020; 102. [PMID: 33331809 DOI: 10.1099/jgv.0.001542] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) is a typical single-layer capsid dsRNA virus belonging to the genus Cypovirus in the family Reoviridae. The results of cryo-electron microscopy showed that the BmCPV capsid consists of 60 asymmetric units, and each asymmetric unit contains one turret protein (TP), two large protrusion proteins (LPP) and two capsid shell proteins (CSP). CSP has the ability to self-assemble into virus-like particles (VLPs), and the small protrusion domain (SPD) in CSP may play an essential role in the assembly of viral capsids. In this study, three critical amino acid sites, D828, S829 and V945, in the SPD were efficiently mutated (point mutation) based on the principle of PCR circular mutagenesis. Moreover, a multi-gene expression system, Ac-MultiBac baculovirus, was used to produce eight different recombinant VLPs in vitro. Transmission electron microscopy showed that the single site and double site mutations had little effect on the efficiency and morphology of the assembly of VLPs. Still, the simultaneous mutation of the three sites had a significant impact. The experimental results demonstrate that the SPD of CSP plays an essential role in assembly of the viral capsid, which lays the foundation for further analysis of the molecular and structural mechanism of BmCPV capsid assembly.
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Affiliation(s)
- Feifei Ren
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Aghia Paraskevi, Athens, Greece.,Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Aghia Paraskevi, Athens, Greece
| | - Qiuyuan Lu
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Yongchao Zhao
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Jiming Yan
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Haiyun Li
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
| | - Jingchen Sun
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, PR China
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He Q, Cao Z, Wang P, Lu Q, Zheng H, Sun J. Efficient application of a baculovirus-silkworm larvae expression system for obtaining porcine circovirus type 2 virus-like particles for a vaccine. Arch Virol 2020; 165:2301-2309. [PMID: 32757056 DOI: 10.1007/s00705-020-04754-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 06/24/2020] [Indexed: 12/11/2022]
Abstract
Porcine circovirus type 2 (PCV2) is a major pathogen associated with swine diseases. It is the smallest single-stranded DNA virus, and its genome contains four major open reading frames (ORFs). ORF2 encodes the major structural protein Cap, which can self-assemble into virus-like particles (VLPs) in vitro and contains the primary antigenic determinants. In this study, we developed a high-efficiency method for obtaining VLPs and optimized the purification conditions. In this method, we expressed the protein Cap with a 6× His tag using baculovirus-infected silkworm larvae as well as the E. coli BL21(DE3) prokaryotic expression system. The PCV2 Cap proteins produced by the silkworm larvae and E. coli BL21(DE3) were purified. Cap proteins purified from silkworm larvae self-assembled into VLPs in vitro, while the Cap proteins purified from bacteria were unable to self-assemble. Transmission electron microscopy confirmed the self-assembly of VLPs. The immunogenicity of the VLPs produced using the baculovirus system was demonstrated using an enzyme-linked immunosorbent assay (ELISA). Furthermore, the purification process was optimized. The results demonstrated that the expression system using baculovirus-infected silkworm larvae is a good choice for obtaining VLPs of PCV2 and has potential for the development of a low-cost and efficient vaccine.
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Affiliation(s)
- Qianhua He
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Zhenming Cao
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Pengwei Wang
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Qiuyuan Lu
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Hao Zheng
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
| | - Jingchen Sun
- Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding and Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
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