Bovine leukemia virus Gag particle assembly in insect cells: Formation of chimeric particles by domain-switched leukemia/lentivirus Gag polyprotein

A key stage in the life cycle of C-type retroviruses is the assembly of Gag precursor protein at the plasma membrane of infected cells. Here we report the assembly of bovine leukemia virus (BLV) gag gene product into virus-like particles (VLPs) using the baculovirus expression system. Expression of BLV Pr44(Gag) resulted in the assembly and release of VLPs, thereby confirming the ability of retroviral Gag polyprotein to assemble and bud from insect cells. Efficient particle formation required a myristoylation signal at the N-terminus of BLV Pr44(Gag). Recombinant baculoviruses expressing matrix (MA) or capsid-nucleocapsid (CA-NC) proteins of BLV were generated but neither of these domains was capable of assembling into particulate structures. To assess the compatibility of Gag domains between leukemia and lentivirus groups three different recombinant chimeras each expressing MA of one virus (e.g. simian immunodeficiency or BLV) and CA-NC of another (e.g. BLV or human T-cell leukemia virus type-I) were constructed. Each of the chimeric proteins assembled efficiently and budded as VLPs, suggesting that the MA and CA domains of these two evolutionary divergent retrovirus groups can be functionally exchanged without perturbation of Gag VLP formation. The lenti-leukemia chimeric Gag approach has potential for studying protein-protein interactions in other retroviruses.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Molecular analysis of genome segment-3 of bluetongue virus serotype 12 isolates from Haryana

Aim: The present study was designed to characterize the genome segment 3 (Seg-3) of bluetongue virus (BTV) serotype 12 isolates from different outbreaks of Bluetongue disease in Haryana, India. Materials and Methods: Blood and swab samples were collected from goat and sheep suspected to be suffering of BT from different outbreaks from Gurugram, Sirsa, Hisar, and Karnal districts of Haryana. The samples were grown in insect and mammalian cell lines. After preliminary identification, serotyping was done using BTV type-specific quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assays. Sequencing was performed using terminal and walking internal primers specific for Seg-3 on ABI Capillary Sequencer 3130 using a "BigDye cycle sequencing kit." The obtained sequence data were analyzed with various bioinformatic tools. Results: Real-time PCR results confirmed the samples to be positive for BTV-12. The Seg-3 of Indian isolates was most closely related to that of a south Indian isolate of BTV-12 from Andhra Pradesh (KC662614) with 97% nucleotide identity. Conclusion: The study confirmed the circulation of BTV-12 in Haryana, India. The variations shown in genome Seg-3 of BTV-12 isolates may have some significance and need to be further explored

A comprehensive study on seroprevalence of bluetongue virus in Haryana state of India

Aim: The aim of present study was to determine seroprevalence of bluetongue virus (BTV) in Haryana state of India. Materials and Methods: A total of 803 serum samples, 408 of cattle and 395 of buffalo origin, respectively, were collected from different villages of Haryana. Sampling was done randomly to obtain unbiased results. The samples were evaluated by a competitive enzyme-linked immunosorbent assay for the presence of BTV antibodies. Results: Overall seroprevalence of BTV antibody in cattle and buffaloes for all 21 districts of Haryana state was found to be 75.49% and 92.91%, respectively. The prevalence of BTV in different agroclimatic zones ranged between 72-77% and 90-94% for cattle and buffalo, respectively. In buffaloes, the BTV seroprevalence was comparatively higher than in cattle. Conclusion: The study showed that BTV is circulating in cattle and buffalo populations in the Northern part of India

Capsid proteins from field strains of foot-and-mouth disease virus confer a pathogenic phenotype in cattle on an attenuated, cell-culture-adapted virus

&lt;p&gt;Chimeric foot-and-mouth disease viruses (FMDVs) have been generated from plasmids containing full-length FMDV cDNAs and characterized. The parental virus cDNA was derived from the cell-culture-adapted O1Kaufbeuren B64 (O1K B64) strain. Chimeric viruses, containing capsid coding sequences derived from the O/UKG/34/2001 or A/Turkey 2/2006 field viruses, were constructed using the backbone from the O1K B64 cDNA, and viable viruses (O1K/O-UKG and O1K/A-Tur, respectively) were successfully rescued in each case. These viruses grew well in primary bovine thyroid cells but grew less efficiently in BHK cells than the rescued parental O1K B64 virus. The two chimeric viruses displayed the expected antigenicity in serotype-specific antigen ELISAs. Following inoculation of each virus into cattle, the rescued O1K B64 strain proved to be attenuated whereas, with each chimeric virus, typical clinical signs of foot-and-mouth disease were observed, which then spread to in-contact animals. Thus, the surface-exposed capsid proteins of the O1K B64 strain are responsible for its attenuation in cattle. Consequently, there is no evidence for any adaptation, acquired during cell culture, outside the capsid coding region within the O1K B64 strain that inhibits replication in cattle. These chimeric infectious cDNA plasmids provide a basis for the analysis of FMDV pathogenicity and characterization of receptor utilization in vivo.&lt;/p&gt;</p

Comparative analysis of the roles of simian immunodeficiency and bovine leukemia virus matrix proteins in Gag assembly in insect cells.

The role of the matrix (MA) domain of simian immunodeficiency virus (SIV) and bovine leukaemia virus (BLV) Gag in the assembly of virus-like particles (VLP) in insect cells has been investigated. Wild-type SIV and BLV Gag assembled to form discrete VLP structures typical of many retroviruses analysed by similar systems. When amino acids predicated by the three-dimensional structure to be at the interface of SIV MA monomers were deleted, VLP assembly was abolished consistent with a role for MA multimerization in assembly. When amino acids predicted to be in the analogous positions in BLV MA were mutated, however, VLP assembly was not affected. These data indicate that the models of assembly derived from one model retrovirus may not necessarily apply to more distantly related viruses despite the structural similarity present in equivalent Gag domains

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Not AvailableThe study investigated the important epidemiological parameters and farm-level economic costs of FMD incidence in cattle and buffaloes during 2013-14 to 2015-16 in various states of India. Multistage random sampling procedure was adopted for the primary survey and data was collected through face-to-face personal interview from 18,609 cattle and buffalo rearing farm households from 123 districts across twelve states and one Union Territory. Besides epidemiological parameters, different farm-level direct and indirect loss associated with FMD was assessed at disaggregated level (states) by employing deterministic mathematical models. Highest number of affected villages and disease incidence was observed in non- FMD control programme (FMD-CP) implemented Madhya Pradesh and Assam states, respectively whereas negligible incidence was in FMD-CP implemented Punjab state. The disease incidence was high during 2013-14 and declined during 2014-15 and 2015-16, respectively implied severe incidence scenario (2013-14) succeeded by moderate (2014-15) and mild (2015-16) scenarios. The crossbred and high productive animals were severely affected than local breeds whereas on sexwise and agewise comparison revealed higher incidence in females and adult animals. During severe incidence scenario, milk loss/animal ranged from USD 6.87-47.44, 18.42-125.88, 16.33-91.43, and 27.17-123.62; mortality loss/animal ranged from USD 32.61-804.27, 30.76-577.7, 65.36-502.2, and 188.04-413.7; distress sale loss/animal ranged from USD 3.22-188.63, 64.34-519.3, 214.47-341.8, and 209.11-450.3; and opportunity cost of labour/animal from USD 5.49-54.29, 5.49-67.78; 7.95-31.37 and 9.83-72.38 in indigenous cattle, crossbred cattle, local and improved buffalo, respectively. The estimated draught power loss/animal varied from USD 39.46-142.94 with least being in Madhya Pradesh and highest in Assam states whereas the median treatment cost/animal was USD 9.18 and USD 27.07 in indigenous cattle and upgraded buffaloes, respectively. The total farm-level economic loss projected due to FMD in cattle and buffaloes in India was USD 3159 million (INR 221,110 million), USD 270 million (INR 18,910 million) and USD 152 million (INR 10,610 million), respectively during the severe, moderate and mild incidence scenarios at 2015-16 constant prices. The loss varied across the states, and in severe incidence scenario, the country might lose USD 3.2 billion/year and hence, the bi-annual vaccination schedule need to be strictly implemented in all the states. Besides timely vaccination coverage, managing unabated animal movement, educating and motivating the farmers to vaccinate their animals might reduce the incidence and consequential losses to various stakeholders in endemic states like IndiaNot Availabl