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Tran THG, Dong VH, Le VT, Vu TN, Dang HA, Huynh TML. Detection and molecular characterization of virulent Newcastle disease virus (subgenotype VII.2) in broiler chickens in Northern Vietnam. Vet World 2023; 16:2086-2095. [PMID: 38023274 PMCID: PMC10668557 DOI: 10.14202/vetworld.2023.2086-2095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/08/2023] [Indexed: 12/01/2023] Open
Abstract
Background and Aim Newcastle disease (ND) is a major viral disease of poultry worldwide. However, data on the molecular characterization of Newcastle disease virus (NDV) in Vietnam are limited. This study aimed to identify the molecular characteristics of NDV strains from the vaccinated chickens farmed in Northern Vietnam. Materials and Methods We used reverse-transcription polymerase chain reaction (PCR), sequencing and phylogenetic analysis to characterize NDV strains from vaccinated chicken farms in Northern Vietnam. Results Seven out of 72 (9.7%) chicken tissue samples collected from seven chicken farms in the four cities/provinces in northern Vietnam were positive for the NDV genome by PCR method. The complete sequences of the fusion (F) and hemagglutinin-neuraminidase (HN) genes of NDVs isolated in the North of Vietnam from 2021 to 2022 were further evaluated. The results indicated that all seven Vietnamese isolates obtained were reported as virulent NDV strains with the amino acid (AA) sequence of the F0 protein proteolytic cleavage site motif (112RRRKRF117). Phylogenetic analysis revealed that they were grouped with other NDV class II from subgenotype VII.2, including the two previous Vietnamese NDV (2015), the Chinese (2017), and Southern African (2013) NDV strains. In addition, some AA substitutions were observed in the neutralizing epitopes of the F and HN proteins of the current Vietnamese NDV strains. Conclusion The present findings provide useful information for future studies of the evolution of NDVs and improve strategies for ND-controlling programs in Vietnam.
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Affiliation(s)
- Thi Huong Giang Tran
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Van Hieu Dong
- Department of Veterinary Public Health, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Van Truong Le
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Thi Ngoc Vu
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Huu Anh Dang
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Thi My Le Huynh
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
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Zhao D, Shen D, Fan H, Zhu X, Wang Y, Duan Y, Chen L. Virulent and attenuated strains of Trichoderma citrinoviride mediated resistance and biological control mechanism in tomato. Front Plant Sci 2023; 14:1179605. [PMID: 37324719 PMCID: PMC10262999 DOI: 10.3389/fpls.2023.1179605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023]
Abstract
Introduction Root-knot nematode disease is one of the world's most serious vegetable crop diseases. In recent years, Trichoderma spp. has been widely used in root-knot nematode disease control as a biological control agent. Methods Virulent and attenuated strains of Trichoderma citrinoviride mediated resistance and biological control mechanism in tomato were determined. Results Preliminary experiments found differences in nematicidal virulence among Trichoderma citrinoviride. The 24-hour corrected mortality rate of the virulent strainT1910 was as high as 92.37%, with an LC50 of 0.5585 against the second juveniles (J2s) of Meloidogyne incognita. And the attenuated strain TC9 was 23.01%, the LC50 was 2.0615, so the virulent strain T1910 had a more substantial effect on the J2s than the attenuated strain. We found that the strong virulent strain T1910 have a good control effect on M. incognita by the pot experiment of tomato than that of the attenuated virulent strain TC9,especially the J2 and J4 numbers were inhibited inside the root knots of tomato. Theinhibition rates of virulent strains reached 85.22% and 76.91%, followed by attenuatedstrain TC9, which were 63.16% and 59.17%, respectively. To reveal the differences intomato defense pathways induced by different virulent strains, qRT-PCR was further usedto detect changes in the expression of inducement-related genes. The results showed thatthe TC9 was significantly upregulated at 5dpi, LOX1, PR1, and PDF1.2. The PR5 gene ofthe virulent strain T1910 was highly upregulated, and the JA pathway was activated laterbut weaker than the attenuated strain. The results of this study revealed that thebiocontrol mechanism of T. citrinoviride as poison killing through the virulent strain T1910 and induced resistance to M. incognita through attenuated strain, although virulence degradation also has an induced resistance effect. Moreover, the attenuated strain TC9 stimulated tomato immune response earlier than the virulent strain by nematode-associated molecular pattern-triggered (NAMP). Discussion Therefore, the research elucidated the mechanism of multiple control of Trichoderma spp. against M. incognita.
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Affiliation(s)
- Di Zhao
- Analysis and Testing Center, Shenyang Agricultural University, Shenyang, China
| | - Dan Shen
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Haiyan Fan
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Xiaofeng Zhu
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Yuanyuan Wang
- College of Life Science and Technology, Shenyang Agricultural University, Shenyang, China
| | - Yuxi Duan
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Lijie Chen
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
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Wu Y, Zhang S, Li Y, Pan C, Wang M, Chen S, Jia R, Yang Q, Zhu D, Liu M, Zhao X, Zhang S, Huang J, Ou X, Mao S, Gao Q, Sun D, Tian B, Cheng A. Establishment and application of a PCR assay for the identification of virulent and attenuated duck plague virus DNA in cotton swabs. Poult Sci 2023; 102:102555. [PMID: 36907124 DOI: 10.1016/j.psj.2023.102555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/28/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Duck plague is an acute, febrile, and septic infectious disease caused by duck plague virus (DPV), which causes serious harm to the duck industry in China. Ducks latently infected with DPV display a clinically healthy state, which is one of the epidemiological characteristics of duck plague. In the present study, to rapidly distinguish vaccine-immunized ducks from wild virus-infected ducks during production, a PCR assay based on the newly identified LORF5 fragment was developed to effectively and accurately identify viral DNA in cotton swab samples and was used to assess artificial infection models and clinical samples. The results showed that the established PCR method had good specificity and that only the virulent and attenuated DNA of duck plague virus was specifically amplified, as the results for the detection of common duck pathogens (duck hepatitis B virus, duck Tembusu virus, duck hepatitis A virus type 1, novel duck reovirus, Riemerella anatipestifer, Pasteurella multocida, and Salmonella) were negative. The amplified fragments of virulent and attenuated strains were 2,454 bp and 525 bp, and their minimum detection amounts were 0.46 pg and 46 pg, respectively. The detection rate of the virulent and attenuated DPV strains in duck oral and cloacal swabs was lower than that of the gold standard PCR method (GB-PCR, which is unable to distinguish virulent and attenuated strains), and cloacal swabs from clinically healthy ducks were more suitable for detection than oral swabs. In conclusion, the PCR assay established in the present study can be used as a simple and effective method for the clinical screening of ducks that are latently infected with virulent strains of DPV and shedding virus, which can provide technical support for the elimination of duck plague from duck farms.
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Sánchez-Carvajal JM, Ruedas-Torres I, Carrasco L, Pallarés FJ, Mateu E, Rodríguez-Gómez IM, Gómez-Laguna J. Activation of regulated cell death in the lung of piglets infected with virulent PRRSV-1 Lena strain occurs earlier and mediated by cleaved Caspase-8. Vet Res 2021; 52:12. [PMID: 33482914 PMCID: PMC7821682 DOI: 10.1186/s13567-020-00882-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023] Open
Abstract
PRRSV-1 virulent strains cause high fever, marked respiratory disease and severe lesions in lung and lymphoid organs. Regulated cell death (RCD), such as apoptosis, necroptosis and pyroptosis, is triggered by the host to interrupt viral replication eliminating infected cells, however, although it seems to play a central role in the immunopathogenesis of PRRSV, there are significant gaps regarding their sequence and activation upon PRRSV-infection. The present study evaluated RCD events by means of caspases expression in the lung of PRRSV-1-infected pigs and their impact on pulmonary macrophage subpopulations and lung lesion. Conventional piglets were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6, 8 and 13 dpi. Lena-infected piglets showed severe and early lung damage with a high frequency of PRRSV-N-protein+ cells, depletion of CD163+ cells and high viral load in the lung. The number of TUNEL+ cells was significantly higher than cCasp3+ cells in Lena-infected piglets during the first week post-infection. cCasp8 and to a lesser extent cCasp9 were activated by both PRRSV-1 strains after one week post-infection together with a replenishment of both CD163+ and Arg-1+ pulmonary macrophages. These results highlight the induction of other forms of RCD beyond apoptosis, such as, necroptosis and pyroptosis during the first week post-infection followed by the activation of, mainly, extrinsic apoptosis during the second week post-infection. The recovery of CD163+ macrophages at the end of the study represents an attempt to restore pulmonary macrophage subpopulations lost during the early stages of the infection but also a macrophage polarisation into M2 macrophages.
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Affiliation(s)
- Jose María Sánchez-Carvajal
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain.
| | - Inés Ruedas-Torres
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain.
| | - Librado Carrasco
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain
| | - Francisco José Pallarés
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain
| | - Enric Mateu
- Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Autonomous University of Barcelona, 08193, Bellaterra, Spain.,Institut de Recerca i Tecnologia Agroalimentàries - Centre de Recerca en Sanitat Animal (IRTA-CReSA), Campus de la Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain
| | - Irene Magdalena Rodríguez-Gómez
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain
| | - Jaime Gómez-Laguna
- Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain
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Yan F, Li E, Li L, Schiffman Z, Huang P, Zhang S, Li G, Jin H, Wang H, Zhang X, Gao Y, Feng N, Zhao Y, Wang C, Xia X. Virus-Like Particles Derived From a Virulent Strain of Pest des Petits Ruminants Virus Elicit a More Vigorous Immune Response in Mice and Small Ruminants Than Those From a Vaccine Strain. Front Microbiol 2020; 11:609. [PMID: 32390966 PMCID: PMC7190788 DOI: 10.3389/fmicb.2020.00609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/19/2020] [Indexed: 11/13/2022] Open
Abstract
Peste des petits ruminants (PPRs) is highly contagious, acute or subacute disease of small ruminants caused by peste des petits ruminants virus (PPRV). To date, several studies have designed and evaluated PPRV-like particles (VLPs) as a vaccine candidate for the prevention and control of PPR, with the majority of these VLPs constructed using sequences derived from a PPRV vaccine strain due to its high immunogenicity. However, because of the lack of available genetic material and certain structural proteins and/or the alteration of posttranslational glycosylation modifications, the immunogenicity of VLPs derived from a vaccine strain is not always optimal. In this study, two PPRV VLP candidates, derived from either the lineage IV Tibet/30 virulent strain or the lineage II Nigeria 75/1 vaccine strain, were generated using a baculovirus system through the coexpression of the PPRV matrix (M), hemagglutinin (H), and fusion (F) proteins in the high expression level cell line High Five. These VLPs were then used to immunize mice, goats, and sheep followed by two boosts after primary immunization. Both VLPs were found to induce a potent humoral immune response as demonstrated by the high ratio of immunoglobulin G1 (IgG1) to IgG2a. In all animals, both VLPs induced high titers of virus-neutralizing antibodies (VNAs), as well as H- and F-specific antibodies, with the Tibet/30 VLPs yielding higher antibody titers by comparison to the Nigeria 75/1 VLPs. Studies in mice also demonstrated that the Tibet/30 VLPs induced a more robust interleukin 4 and interferon γ response than the Nigeria 75/1 VLPs. Goats and sheep immunized with both VLPs exhibited a robust humoral and cell-mediated immune response. Furthermore, our results demonstrated that the VLPs derived from the virulent lineage IV Tibet/30 strain were more immunogenic, inducing a more potent and robust humoral and cell-mediated immune response in vaccinated animals by comparison to the lineage II Nigeria 75/1 vaccine strain VLPs. In addition, VNA titers were significantly higher among animals vaccinated with the Tibet/30 VLPs by comparison to the Nigeria 75/1 VLPs. Taken together, these findings suggest that VLPs derived from the virulent lineage IV Tibet/30 strain are more immunogenic by comparison to those derived from the lineage II Nigeria 75/1 vaccine strain and thus represent a promising vaccine candidate for the control and eradication of PPR.
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Affiliation(s)
- Feihu Yan
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Entao Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ling Li
- National Research Center for Exotic Animal Diseases, China Animal Health and Epidemiology Center, Qingdao, China
| | - Zachary Schiffman
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada.,National Microbiology Laboratory, Special Pathogens Program, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Pei Huang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin Agricultural University, Changchun, China
| | - Shengnan Zhang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Wildlife Resources, Northeast Forestry University, Harbin, China
| | - Guohua Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Animal Science and Technology, Shihezi University, Shihezi, China
| | - Hongli Jin
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - Hualei Wang
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xinghai Zhang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yuwei Gao
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Na Feng
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Yongkun Zhao
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Chengyu Wang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Xianzhu Xia
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.,College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,College of Veterinary Medicine, Jilin Agricultural University, Changchun, China
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Rebelo M, Ding L, Cordeiro AI, Neves C, Simões MJ, Zelazny AM, Holland SM, Neves JF. Fatal Meningitis in Patient with X-Linked Chronic Granulomatous Disease Caused by Virulent Granulibacter bethesdensis. Emerg Infect Dis 2019; 25:976-979. [PMID: 31002074 PMCID: PMC6478198 DOI: 10.3201/eid2505.181505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Granulibacter bethesdensis is a pathogen reported to cause recurrent lymphadenitis exclusively in persons with chronic granulomatous disease. We report a case of fatal meningitis caused by a highly virulent G. bethesdensis strain in an adolescent in Europe who had chronic granulomatous disease.
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Zurawski DV, Reinhart AA, Alamneh YA, Pucci MJ, Si Y, Abu-Taleb R, Shearer JP, Demons ST, Tyner SD, Lister T. SPR741, an Antibiotic Adjuvant, Potentiates the In Vitro and In Vivo Activity of Rifampin against Clinically Relevant Extensively Drug-Resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2017; 61:e01239-17. [PMID: 28947471 DOI: 10.1128/AAC.01239-17] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/05/2017] [Indexed: 11/21/2022] Open
Abstract
Acinetobacter baumannii is responsible for 10% of all nosocomial infections and has >50% mortality rates when causing ventilator-associated pneumonia. In this proof-of-concept study, we evaluated SPR741, an antibiotic adjuvant that permeabilizes the Gram-negative membrane, in combination with rifampin against AB5075, an extensively drug-resistant (XDR) A. baumannii strain. In standard in vitro assays and in a murine pulmonary model, we found that this drug combination can significantly reduce bacterial burden and promote animal survival despite an aggressive infection.
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Islam MR, Zierenberg K, Müller H. The genome segment B encoding the RNA-dependent RNA polymerase protein VP1 of very virulent infectious bursal disease virus (IBDV) is phylogenetically distinct from that of all other IBDV strains. Arch Virol 2001; 146:2481-92. [PMID: 11811695 PMCID: PMC7086636 DOI: 10.1007/s007050170018] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A full-length cDNA clone of the segment B of the very virulent infectious bursal disease virus (IBDV) strain BD 3/99 was constructed and the full-length nucleotide sequence was established. The nucleotide sequence encoding VP1, an RNA-dependent RNA polymerase, of BD 3/99 was aligned with that of 17 other IBDV strains including six very virulent, three classical virulent, five classical attenuated, one antigenic variant and two serotype 2 strains. The VP1 genes of all very virulent strains were 97.5% to 99.8% identical. With the exception of an atypical Australian strain, 002-73, all of the classical virulent or attenuated and antigenic variant strains were also 97.5% to 100% identical. Serotype 2 strains showed only 4-6% divergence from serotype 1 classical virulent or attenuated strains; in contrast, however, the very virulent strains were 10.5% to 12.5% divergent from the classical virulent or attenuated strains as well as serotype 2 strains. Analysis of the deduced amino acid sequence of VP1 revealed 17 common, including 8 unique amino acid substitutions in the very virulent strains. In the phylogenetic tree the very virulent strains formed a distinct cluster and all other strains including classical virulent, attenuated and antigenic variant strains and even serotype 2 strains were grouped together. It is suggested that the VP1 of very virulent IBDV is phylogenetically distinct from that of all other IBDV strains and probably originated from a hitherto unidentified source.
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Affiliation(s)
- M R Islam
- Institute of Virology, Faculty of Veterinary Medicine, University of Leipzig, Germany
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Storz J, Zhang XM, Rott R. Comparison of hemagglutinating, receptor-destroying, and acetylesterase activities of avirulent and virulent bovine coronavirus strains. Arch Virol 1992; 125:193-204. [PMID: 1642550 PMCID: PMC7087242 DOI: 10.1007/bf01309637] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hemagglutinating and acetylesterase functions as well as the 124 kDa glycoprotein were present in the highly cell-culture adapted, avirulent bovine coronavirus strain BCV-L9, in the Norden vaccine strain derived from it, and in 5 wild-type, virulent strains that multiplied in HRT-18 cells but were restricted in several types of cultured bovine cells. The BCV-L9 and the wild-type strain BCV-LY-138 agglutinated chicken and mouse erythrocytes. The acetylesterase facilitated break-down of the BCV-erythrocyte complex with chicken but only to a minimal extent with mouse erythrocytes in the receptor-destroying enzyme test. Purified preparations of the vaccine and the wild-type strains agglutinated chicken erythrocytes at low titers and mouse erythrocytes at 128 to 256 times higher titers whereas receptor destroying enzyme activity was detectable only with chicken erythrocytes. When wild-type strains were propagated in HRT cells at low passage levels, they produced 5 x 10(5) to 4.5 x 10(6) plaque forming units per 50 microliters which agglutinated erythrocytes from mice but not from chickens. Diisopropylfluoro-phosphate moderately increased the hemagglutination titers, but completely inhibited the receptor destroying enzyme of purified virus of all strains. It had virtually no influence on the plaque-forming infectivity of the different BCV strains. The acetylesterase of strain BCV-L9 reacting in the receptor-destroying enzyme test was stable for 3 h at 37 and 42 degrees C. It was inactivated within 30 min at 56 degrees C while the hemagglutinin function of this strain was stable for 3 h at 37, 42, and 56 degrees C, but it was inactivated at 65 degrees C within 1 h.
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Affiliation(s)
- J Storz
- Department of Veterinary Microbiology and Parasitology, School of Veterinary Medicine, Louisiana State University, Baton Rouge
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