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1.
Int J Mol Sci ; 23(21)2022 Oct 30.
Article in English | MEDLINE | ID: covidwho-2090211

ABSTRACT

Porcine reproductive and respiratory syndrome virus is a positive-stranded RNA virus of the family Arteriviridae. The Gp5/M dimer, the major component of the viral envelope, is required for virus budding and is an antibody target. We used alphafold2, an artificial-intelligence-based system, to predict a credible structure of Gp5/M. The short disulfide-linked ectodomains lie flat on the membrane, with the exception of the erected N-terminal helix of Gp5, which contains the antibody epitopes and a hypervariable region with a changing number of carbohydrates. The core of the dimer consists of six curved and tilted transmembrane helices, and three are from each protein. The third transmembrane regions extend into the cytoplasm as amphiphilic helices containing the acylation sites. The endodomains of Gp5 and M are composed of seven ß-strands from each protein, which interact via ß-strand seven. The area under the membrane forms an open cavity with a positive surface charge. The M and Orf3a proteins of coronaviruses have a similar structure, suggesting that all four proteins are derived from the same ancestral gene. Orf3a, like Gp5/M, is acylated at membrane-proximal cysteines. The role of Gp5/M during virus replication is discussed, in particular the mechanisms of virus budding and models of antibody-dependent virus neutralization.


Subject(s)
Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine , Animals , Porcine respiratory and reproductive syndrome virus/genetics , Viral Envelope Proteins/metabolism , Epitopes , Virus Replication
2.
Chinese Veterinary Science / Zhongguo Shouyi Kexue ; 50(11):1373-1378, 2020.
Article in Chinese | CAB Abstracts | ID: covidwho-2040499

ABSTRACT

In order to build a specific, sensitive and rapid detection method for PAstV3 detection, the PAstVB gene sequences in Genbank were used and the conserved region in ORFlb was selected to design specific primers and TaqMan probe. Clinical stool samples were collected and preliminary detected by this newly established real-time RT-PCR method after reaction systems and conditions optimization. This detection method established in this study has a good linear relationship with the standard curve, with R2 value up to 0.9971. The sensitivity is 100 times higher than conventional PCR method, The variation co-efficient of in-batch and inter-batch repeatability test is less than 2.0%, indicating good repeatability. The detection results of Clinical samples showed that the positive rate of this method is higher than conventional PCR method. The establishment of this method provides a rapid detection means for PAstV3 laboratory diagnosis and epidemiological investigation.

3.
Chinese Veterinary Science / Zhongguo Shouyi Kexue ; 50(7):825-832, 2020.
Article in Chinese | CAB Abstracts | ID: covidwho-1994655

ABSTRACT

In order to establish a method for rapid differential identification of Senecavirus A (SVA) and en-cephalomyocarditis virus (EMCV), two pairs of corresponding specific primers were designed based on the highly conserved 3D genes of SVA and EMCV. And two different fluorescent labeled TaqMan probes were used to establish a dual TaqMan real-time PCR method for simultaneous detection of these two viruses, and we also optimize the reaction conditions. The results showed that the minimum detection of the method was 760 copies/ micro L and 98 copies/ micro L for SVA and EMCV. respectively, and it can specifically detect SVA and EMCV, and there was no cross reaction with CSFV, PRRSV and PEDV. The established standard curves showed good linear relationship. Repeated experimental group and inter-group coefficient of variation were less than 5%. The results indicated that the dual-quantitative PCR established in this study has the advantages of convenience, rapidity, good specificity. high sensitivity and good repeatability .and can be used for simultaneous detection of SVA and EMCV.

4.
Bulletin des GTV ; 104:85-92, 2021.
Article in French | CAB Abstracts | ID: covidwho-1957885

ABSTRACT

Coronaviruses have a high evolutionary capacity which has led to their very large genetic diversity. Their prevalence in nature is very high and they can infect a wide spectrum of hosts including mammals (including humans) and birds. To date, six porcine coronaviruses have been identified. Two of which were responsible for severe epizootics in pigs with a major impact in the global swine industry in the 60's to 80's for porcine transmissible gastroenteritis virus and since the 2010's in China and 2014 in North America for porcine epidemic diarrhoea virus. The latter has also become the third most important pathogen for pigs in China after the African swine fever virus and the porcine reproductive and respiratory syndrome virus. This review summarizes the latest developments in scientific knowledge of these porcine coronaviruses.

5.
Comput Struct Biotechnol J ; 20: 3409-3421, 2022.
Article in English | MEDLINE | ID: covidwho-1926353

ABSTRACT

Equine arteritis virus (EAV) and porcine reproductive and respiratory syndrome virus (PRRSV) represent two members of the family Arteriviridae and pose a major threat to the equine- and swine-breeding industries throughout the world. Previously, we and others demonstrated that PRRSV 3C-like protease (3CLpro) had very high glutamic acid (Glu)-specificity at the P1 position (P1-Glu). Comparably, EAV 3CLpro exhibited recognition of both Glu and glutamine (Gln) at the P1 position. However, the underlying mechanisms of the P1 substrate specificity shift of arterivirus 3CLpro remain unclear. We systematically screened the specific amino acids in the S1 subsite of arterivirus 3CLpro using a cyclized luciferase-based biosensor and identified Gly116, His133 and Ser136 (using PRRSV 3CLpro numbering) are important for recognition of P1-Glu, whereas Ser136 is nonessential for recognition of P1-Gln. Molecular dynamics simulations and biochemical experiments highlighted that the PRRSV 3CLpro and EAV 3CLpro formed distinct S1 subsites for the P1 substrate specificity switch. Mechanistically, a specific intermolecular salt bridge between PRRSV 3CLpro and substrate P1-Glu (Lys138/P1-Glu) are invaluable for high Glu-specificity at the P1 position, and the exchange of K138T (salt bridge interruption, from PRRSV to EAV) shifted the specificity of PRRSV 3CLpro toward P1-Gln. In turn, the T139K exchange of EAV 3CLpro showed a noticeable shift in substrate specificity, such that substrates containing P1-Glu are likely to be recognized more efficiently. These findings identify an evolutionarily accessible mechanism for disrupting or reorganizing salt bridge with only a single mutation of arterivirus 3CLpro to trigger a substrate specificity switch.

6.
Surveillance ; 48(4):10-24, 2021.
Article in English | CAB Abstracts | ID: covidwho-1887621

ABSTRACT

Exotic pest and disease investigations are managed and reported by the Ministry for Primary Industries' (MPI's) Diagnostic and Surveillance Directorate. This article presents a summary of investigations of suspect exotic and emerging pests and diseases in New Zealand during the period from July to September 2021.

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