Diversity assessment of a lesser known buffalo population from Central India and its comparative evaluation reveals presence of sufficient genetic variation and absence of selection

Planned breeding and conservation strategies for a lesser-known population require an assessment of complete genetic diversity and population structure analysis in addition to its morphometric characteristics. In the present study, a comparative analysis of the genetic structure of a rare buffalo population, namely Chhattisgarhi, was extensively studied using a panel of FAO-recommended microsatellite markers along with well-established breeds namely Murrah, Nili-Ravi, Gojri, Kalahandi, and Nagpuri. Mode shift analysis indicated the absence of genetic bottleneck in the recent past. Assessment of genetic diversity indices across all loci indicated the presence of sufficient genetic variation within and between populations. Analysis of molecular variance between the six different buffalo populations attributed 19.05% of the variations to between-population differentiation. Cluster analyses using DAPC and Bayesian approach along with the phylogenetic tree based on UPGMA grouped six populations into three groups. The Chhattisgarhi population was revealed to be genetically closer to Nagpuri and Kalahandi populations. The study reveals the presence of sufficient genetic diversity within the Chhattisgarhi population and indicates the absence of a systematic selection program. We suggest improvement and conservation programs should be planned for this breed in the near future through short-term selection.

Discriminant analysis reveals differences in breed structure in river buffaloes of Maharashtra (India)

Buffaloes are a major milch species of India, and owning a true-to-breed buffalo herd is a reverie for livestock keepers, as it substantiates their incomes. Multivariate discriminate analysis is an efficient methodology to classify different farm animal populations based on canonical discriminant function. The present study was conducted on 392 adult buffaloes using 18 body biometric traits. Except for body height and body length, all the body characters revealed significant differences amongst the four buffalo populations. Unlike cattle, distance between horns and rump width were more discriminating factors, compared to body height, leg length, chest girth, and body length. We report the most suitable discriminate function which can discriminate with maximum between-group variation in four studied populations. Mahalanobis distances were calculated between populations and they ranged from 0.786 to 1.227. Purnathadi has revealed a distinct phenotypic structure, and these buffaloes have a distinct native breeding region comprising Akola, Amravati, and Buldhana districts of Maharashtra state. On the other hand, Elachpuri animals failed to depict physical and biometric discriminations from Nagpuri, Marathwadi, and Purnathadi buffalo populations, and Elachpuri can be considered as a strain of Nagpuri buffalo.

Identification of novel polymorphism in mammary-derived growth inhibitor gene of water buffalo and its expression analysis in the mammary gland

Mammary-derived growth inhibitor (MDGI), a member of the lipophilic family of fatty acid-binding proteins, plays an important role in the development, regulation, and differentiation of the mammary gland. The aim of the study was to identify polymorphism in the MDGI gene and its expression analysis in the mammary gland at various stages of lactation, in Indian buffalo. Nucleotide sequence analysis of MDGI gene in different breeds of riverine and swamp buffaloes revealed a total of 16 polymorphic sites and one Indel. Different transcription factor binding sites were predicted for buffalo MDGI gene promoter sequence, using online tools and in-silico analysis indicating that the SNPs in this region can impact the gene expression regulation. Phylogenetic analysis exhibited the MDGI of buffalo being closer to other ruminants like cattle, yak, sheep, and goats. Further, the expression analysis revealed that buffalo MDGI being highly expressed in well-developed mammary glands of lactating buffalo as compared to involution/non-lactating and before functional development to start the milk production stage in heifers. Stage-specific variation in expression levels signifies the important functional role of the MDGI gene in mammary gland development and milk production in buffalo, an important dairy species in Southeast Asia.

Genetic characterization and diversity assessment in 'Bhangor' indigenous swamp buffalo population using heterologous microsatellite markers

'Bhangor' newly identified swamp buffalo population from North East Indian, was characterized using microsatellite markers. Genomic DNA was isolated from blood samples of 76 unrelated animals, 15 microsatellite markers (CSSM33, BM1818, CSRM60, HEL13, ILSTS019, ILSTS025, ILSTS028, ILSTS029, ILSTS033, ILSTS036, ILSTS056, ILSTS058, ILSTS061, ILSTS089 and ETH003) were found to be highly polymorphic in the population of the selected markers. A total of 114 alleles were observed, which ranged from 3 in CSRM60 and ILSTS025 locus to 12 in ILSTS056 and ILSTS061. The mean effective number of alleles across all polymorphic loci was found to be 3.76. The overall mean expected heterozygosity and unbiased expected heterozygosity values were 0.67 and 0.68, ranging from 0.067 (ILSTS025) to 0.85 (ILSTS058) and 0.068 (ILSTS025) to 0.86 (ILSTS058), respectively. Within the population, the inbreeding estimates (FIS) ranged between -0.4352 and 0.804, with an average FIS of 0.114 ± 0.033. The outcome for infinite allele model (IAM), two-phase model (TPM) and test for mode shift revealed the absence of any recent bottleneck in the investigated buffalo population. The population was found to be in optimum diversity based on polymorphic microsatellite markers. With fast changing agro-climatic conditions; there is an urgent need to characterize the nondescript livestock populations.

Perioperative enfortumab vedotin (EV) plus pembrolizumab (pembro) versus chemotherapy in cisplatin-eligible patients (pts) with muscle-invasive bladder cancer (MIBC): Phase 3 KEYNOTE-B15/EV-304

TPS588

Background: Neoadjuvant cisplatin-based chemotherapy followed by radical cystectomy + pelvic lymph node dissection (RC+PLND) is the standard of care for cisplatin-eligible pts with MIBC; however, up to 50% of pts will experience disease recurrence or progression following treatment. Pembro and EV monotherapies are approved for use in select pts with metastatic urothelial carcinoma (mUC). Furthermore, results of the phase 1/2 KEYNOTE-869/EV-103 study showed encouraging antitumor activity and an acceptable safety profile with first-line combination therapy EV + pembro in cisplatin-ineligible pts with mUC. The open-label, multicenter, phase 3, randomized KEYNOTE-B15/EV-304 study (NCT04700124) will compare the efficacy and safety of perioperative EV + pembro versus neoadjuvant cisplatin-based chemotherapy in cisplatin-eligible pts with MIBC. Methods: Eligible pts will have histologically confirmed UC/MIBC (T2-T4aN0M0 or T1-T4aN1M0) with predominant urothelial histology (≥50%), nonmetastatic disease (N≤1, M0) confirmed by blinded independent central review (BICR), ECOG performance status of 0-1, no prior systemic therapy for MIBC, and agree to undergo curative RC+PLND. Approximately 784 pts will be randomly assigned 1:1 to Arm A (4 cycles of neoadjuvant EV + pembro, followed by RC+PLND, followed by 5 cycles of adjuvant EV + 13 cycles of adjuvant pembro) or Arm B (4 cycles of neoadjuvant chemotherapy [gemcitabine + cisplatin] followed by RC+PLND, followed by observation). Neoadjuvant and adjuvant pembro 200 mg + EV 1.25 mg/kg will be administered intravenously every 3 weeks (Q3W) on day 1 (pembro + EV) and day 8 (EV) of each cycle. Neoadjuvant chemotherapy is gemcitabine 1000 mg/m2 + cisplatin 70 mg/m2 Q3W on day 1 (gemcitabine + cisplatin) and day 8 (gemcitabine) of each cycle. Stratification factors are disease stage (T2N0 vs T3/T4aN0 vs T1-T4aN1), PD-L1 combined positive score (≥10 vs <10), and geographic region (United States vs European Union vs most of the world). Imaging by CT (preferred) or MRI will be performed ≤6 weeks before cystectomy and 6 weeks after cystectomy. Imaging will occur following cystectomy then Q12W through year 2 and at discontinuation, then Q24W in year 3 and beyond. Adverse events (AEs) will be monitored throughout the study and for 30 days following cessation of treatment (90 days for serious AEs). The primary end points are pathologic complete response rate and event-free survival by BICR. Secondary end points are OS, DFS, pathologic downstaging rate, safety and tolerability, and patient-reported outcomes. KEYNOTE-B15/EV-304 is enrolling in Africa, Asia, Australia, Europe, and North America. © 2021 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2021 ASCO Annual Meeting. All rights reserved. Clinical trial information: NCT04700124 .

Patient-reported outcomes (PROs) in cisplatin-ineligible patients (pts) with locally advanced or metastatic urothelial cancer (la/mUC) treated with enfortumab vedotin (EV) alone or in combination with pembrolizumab (P) in the phase 1b/2 EV-103 Cohort K study

439

Background: The EV-103 Cohort K trial evaluated 1L EV+P or EV alone (NCT03288545) in pts with la/mUC who were cisplatin-ineligible. EV+P showed a clinically meaningful objective response rate (64.5%; 95% CI, 52.7–75.1) with a manageable safety profile. Because la/mUC is associated with symptoms with a frequent impact on quality of life (QOL) and functioning (Mamtani et al. JCO 2021), we describe the impact of EV+P or EV alone on QOL and symptoms. Methods: In this open-label, Phase 1b/2 trial, cisplatin-ineligible pts with la/mUC were randomized 1:1 to EV+P or EV alone. For exploratory PRO endpoints, pts completed EORTC QLQ-C30 and the BPI-SF at baseline, weekly for cycles 1–3, and once every cycle for the remainder of treatment period. The PRO analysis set included only pts who were treated and completed the questionnaire at baseline. Mixed effect models for repeated measures (MMRM; least squares [LS] mean, standard error [SE]) not adjusted for multiplicity, estimated change vs baseline until Week 24; established thresholds (EORTC QLQ-C30: 10-point change; BPI-SF: 2-point change) were applied to determine clinically meaningful change. Results: Of the 76 pts treated with EV+P, 65 were included in the PRO analysis set. EORTC QLQ-C30 and BPI-SF were completed by 100% and 95%, respectively, at baseline; compliance rates were ≥84% for both instruments through Week 24. In the EORTC QLQ-C30 MMRM analyses, QOL was maintained through Week 24 for EV+P; functioning and symptom scores remained stable over time, with improvements in emotional functioning, pain and sleep disturbance vs observed baseline. In the EV+P arm, clinically meaningful reductions in pain were seen at Week 12 (-12.64 [3.208]) vs baseline and persisted through Week 24 (-13.20 [3.406]). In the BPI-SF MMRM analyses, worst and average pain, pain interference and severity consistently showed improved scores from Week 4–24 for EV+P; clinically meaningful change in worst pain was seen at Week 21 (-2.08 [0.361]). Similar completion and compliance rates were seen for the EV alone PRO analysis set (n=63). EV alone demonstrated clinically meaningful improvements in pain at Week 24 in the EORTC QLQ-C30 (-10.63 [4.110]) and consistent small-to-moderate improvements in the BPI worst and average pain, and pain severity (0.5–1.0 points). Sleep disturbances demonstrated improvement, and other symptom scales, QOL and functional domains remained stable. Conclusions: PRO data showed that EV+P in cisplatin-ineligible pts with la/mUC was associated with preservation or improvement of QOL, functioning, and symptoms. Improvement in pain was demonstrated consistently in both PRO instruments and treatment arms. These PRO data complement the clinical outcomes of EV+P in 1L cisplatin-ineligible pts with la/mUC. Clinical trial information: NCT03288545 .

Expression profile of different classes of proteases in milk derived somatic cells across different lactation stages of indigenous cows (Bos indicus) and riverine buffaloes (Bubalus bubalis)

Proteases play a significant role in milk and its products by affecting flavor, texture and longevity. The expression of endogenous proteases varies across different stages of lactation. The study was conducted to understand the transcriptional pattern of different classes of protease-pathways associated genes (CTSB, CTSD, CTSH, CTSL, CTSK, CTSS, CTSZ, PLAU, PLAT) and potential protease inhibitors (SERPIN E2 and SERPIN F2) in 40 milk somatic cells (MSC) samples isolated during early, peak, mid and late lactation stages of Sahiwal cows and Murrah buffaloes - the two most important dairy breeds of India. In Sahiwal cows, except CTSK and PLAU, the expression of other proteases class was not affected significantly (p > 0.05) across lactation stages. However, in Murrah buffaloes, the expression of different proteases increased as the lactation progressed. Most of the proteases showed lower expression during early and peak lactation stages while their expression tends to increase during mid to late lactation stages. The overall trend was somewhat similar in both the dairy species albeit the level of expression was higher in buffalo MSC as compared to cow MSC. The study has provided valuable information on expression kinetics of different proteases in milk somatic cells of two major dairy breeds of India.

Identification of novel allelic patterns and evolutionary lineage of BoLA MHC class II DQA locus in indicine and taurine cattle

Among different cattle types, Bos indicus are known for their ability to better resist the tropical microbial infections comparatively, wherein MHC molecules play a significant role. In this study allelic diversity at MHC locus, DQA of Bos indicus, Bos taurus and crossbred of taurine-indicus has been explored to understand the possible role of MHC region in differential immune response. Thirty nine different DQA alleles were identified, out of which 14 were novel, along with documentation of duplication of DQA alleles. Indicus cattle population presented diverse types of DQA alleles compared to crossbred and exotic. Translated amino acid sequence analysis indicated, codon 64 and 50 of peptide binding sites being highly polymorphic and most of the indicus cattle presented alanine and arginine amino acid at position 64 and 50. Within breed genetic variation found to be higher than between breeds. Because of their ability to bind and subsequently respond to a wide array of antigens, the newly identified DQA alleles with high diversity present in the form of duplicated haplotypes in different combinations in cattle populations provided significant insights into probable role of this MHC locus in better tropical disease combating ability and genetic fitness of indicus cattle.

Study EV-302: A two-arm, open-label, randomized controlled phase 3 study of enfortumab vedotin in combination with pembrolizumab versus chemotherapy in previously untreated advanced urothelial carcinoma (aUC) (trial in progress)

TPS589

Background: Platinum-based chemotherapy is standard first line (1L) therapy for aUC. Maintenance therapy may be offered for patients (pts) who do not progress on 1L chemotherapy. However, not all pts are eligible for maintenance therapy, with many succumbing to their disease prior to 2L. Therefore, there is a persistent unmet need for safe and effective drug combinations in the 1L setting. Enfortumab vedotin (EV) is a Nectin-4 directed antibody-drug conjugate (ADC) comprised of a fully human mAb conjugated to the microtubule-disrupting agent, monomethyl auristatin E (MMAE), via a protease-cleavable linker. EV has previously shown an OS benefit vs chemotherapy in pts with locally advanced or metastatic urothelial carcinoma who had previously received platinum-based therapy and a PD-(L)1 inhibitor (Powles NEJM 2021). EV is FDA-approved in this and other settings (PADCEV, Seagen Inc., 2021). Preclinical studies showed that MMAE containing ADCs, including EV, induce evidence of immunogenic cell death and can enhance anti-tumor immunity, thereby laying the foundation for EV-PD-1/PD-L1 inhibitor combination (Liu Cancer Res 2020; Cao Can Res 2016). EV-302 will evaluate the efficacy and safety of EV+pembrolizumab (EV+P) combination vs gemcitabine+cisplatin (gem+cis) or carboplatin (carbo) in pts with previously untreated aUC. Methods: EV-302/KN-A39 (NCT04223856) evaluates EV+P combination vs gem+cis or carbo in previously untreated pts with aUC. Eligibility criteria include pts with measurable disease, an ECOG status of ≤2, and eligible to receive EV, P, and cis or carbo. EV+P combination includes EV (1.25 mg/kg) administration on Days 1 and 8 with P (200 mg) on Day 1. Gem+cis or carbo includes: gem (1000 mg/m2) on Days 1 and 8; and cis (70 mg/m2) or carbo (AUC 4.5 or 5) on Day 1 of every 3-wk cycle. Randomization is 1:1 with stratification factors: cis eligibility, PD-L1 expression, and liver metastases. The primary endpoints are PFS and OS for EV+P compared to gem+cis or carbo. Other endpoints include ORR, duration of response, disease control rate, AEs, patient reported outcomes, PK, and biomarkers. The study opened March 2020 with sites actively enrolling globally. Clinical trial information: NCT04223856.

KEYNOTE-B15/EV-304: Randomized phase 3 study of perioperative enfortumab vedotin plus pembrolizumab versus chemotherapy in cisplatin-eligible patients with muscle-invasive bladder cancer (MIBC)

TPS4587

Background: Standard of care for MIBC is neoadjuvant cisplatin-based chemotherapy followed by radical cystectomy and pelvic lymph node dissection (RC+PLND); however, in time, patients experience disease recurrence or progression. Enfortumab vedotin (EV) is a Nectin-4–directed antibody–drug conjugate comprising a fully human, monoclonal antibody and the microtubule-disrupting agent monomethyl auristatin E. The KEYNOTE-869/EV-103 phase 1/2 study (NCT03288545) showed that the PD-1 inhibitor pembrolizumab + EV had encouraging antitumor activity and acceptable safety as first-line treatment for cisplatin-ineligible patients with metastatic urothelial cancer (Rosenberg JE et al. J Clin Oncol. 2020;38[15 suppl]:5044). Based on these data, investigating EV + pembrolizumab in an earlier setting such as MIBC and in a perioperative fashion is appropriate. KEYNOTE-B15/EV-304 (NCT04700124) is a randomized, open-label, phase 3 study to evaluate the efficacy and safety of perioperative EV + pembrolizumab versus neoadjuvant chemotherapy using gemcitabine/cisplatin in cisplatin-eligible patients with MIBC. Methods: Patients must have histologically confirmed urothelial cancer/MIBC (clinical stage T2-T4aN0M0 or T1-T4aN1M0) with predominant (≥50%) urothelial histology, have nonmetastatic disease (≥N2 disease and/or M1 excluded) confirmed by blinded independent central review (BICR), have ECOG PS 0 or 1, and not have previously received systemic therapy for MIBC. Approximately 784 patients will be randomly assigned 1:1 to receive either 4 cycles of neoadjuvant EV + pembrolizumab followed by 5 cycles of adjuvant EV + 13 cycles of adjuvant pembrolizumab after RC+PLND or 4 cycles of neoadjuvant cisplatin-based chemotherapy followed by observation after RC+PLND. Neoadjuvant and adjuvant pembrolizumab 200 mg + EV 1.25 mg/kg will be administered intravenously every 3 weeks (Q3W), and neoadjuvant chemotherapy will consist of gemcitabine 1000 mg/m2 + cisplatin 70 mg/m2 Q3W. Randomization will be stratified by centrally determined (pathology or imaging) initial T and N stage (T2N0 or T3/T4aN0 or T1-T4aN1), PD-L1 combined positive score (CPS ≥10 or CPS < 10), and geographic region (United States or Europe or most of world). Imaging (CT or MRI) will be performed ≤6 weeks before cystectomy and 6 weeks after cystectomy. After postcystectomy imaging, additional imaging will be performed Q12W up to the end of year 2 (week 96) and at discontinuation. In year 3 and beyond, imaging will be performed Q24W. Primary end points are pathological complete response and event-free survival by BICR. Secondary end points are overall survival, disease-free survival, pathological downstaging, and safety and tolerability. Clinical trial information: NCT04700124.

Study EV-103: Update on durability results and long term outcome of enfortumab vedotin + pembrolizumab in first line locally advanced or metastatic urothelial carcinoma (la/mUC)

4528

Background: Significant unmet need remains for people with cisplatin-ineligible (cis-ineligible) locally advanced or metastatic urothelial carcinoma (la/mUC). In the first-line (1L) setting, carboplatin-based regimens have demonstrated poor tolerability, modest objective response rate (ORR) and limited durability. PD-1/PD-L1 inhibitors demonstrate durable responses; however, only a minority of pts achieve a response (ORR 24-29%). Enfortumab vedotin (EV) is an antibody-drug conjugate (ADC) delivering the microtubule-disrupting agent monomethyl auristatin E (MMAE) to targeted tumor cells expressing Nectin-4. EV has shown an overall survival benefit versus chemotherapy in previously treated la/mUC. Preclinical studies show that ADCs utilizing MMAE can induce immunogenic cell death and may enhance antitumor immunity. Clinical data suggests the combination of EV + pembrolizumab (P) may have the potential to induce greater antitumor activity compared to either agent alone. Preliminary data on EV + P was previously presented, and the FDA granted breakthrough therapy designation to EV + P for the treatment of pts with 1L cis-ineligible la/mUC in Feb 2020. Here we report updated data with 24.9 months median follow-up. Methods: This multi-cohort EV-103 study (NCT03288545) evaluates the safety/activity of EV + P (Dose Escalation/Cohort A). This report highlights 1L cis-ineligible pts treated with 3-week cycles of EV 1.25 mg/kg (Days 1, 8) and P (Day 1). Endpoints include safety/tolerability, investigator response per RECIST v1.1, DOR, PFS, and OS. Results: As of 13 Oct 2020, the median follow-up for the 45 1L la/mUC pts (median age 69 yrs [51-90]) was 24.9 months. The median number cycles of EV + P was 9 (range 1-34). The most common treatment-related adverse events were peripheral sensory neuropathy (56%, 4% ≥G3), fatigue (51%, 11% ≥G3), and alopecia (49%). There was one death reported as possibly related to study treatment (multiple organ dysfunction syndrome) per investigator assessment. Confirmed ORR is 73.3% (95% CI: 58.1, 85.4) including 17.8% CR and an ORR of 57.1% (8/14) in pts with liver metastasis. The median DOR was 25.6 months (95% CI: 8.3, -). Fifty-three percent of the responders had DOR at 24 months. Additionally, the DCR is 93.3%, the median PFS is 12.3 months (95% CI: 8.0, -), and the median OS is not reached. The OS rate at 24 months is 56.3% (95% CI: 39.8, 69.9). Conclusions: EV + P, a platinum-free option, continues to demonstrate promising activity with a durable response profile in 1L cis-ineligible pts with la/mUC. The safety profile is manageable and stable over time with no new safety signals. Cohort K of EV-103 in cis-ineligible pts with la/mUC is actively randomizing pts to EV monotherapy or EV + P to evaluate the contribution of each agent. Clinical trial information: NCT03288545.

In Silico Analysis of HSP70 Gene Family in Bovine Genome

Heat shock proteins (HSPs), members of molecular chaperones families fulfill essential roles under normal conditions and provide protection and adaptation during and after stress. Among different HSPs, HSP70 kDa family of proteins is most abundant and well-studied in human and mouse but has not yet been characterized in bovines. In silico analysis was performed to characterize members of HSP70 gene family in bovine genome and a total of 17 genes of bovine HSP70 gene family were identified. The members of HSP70 family were distributed over 12 chromosomes with gene size ranging from 1911 (HSPA2) to 54,017 bp (HSPA4). Five genes were intronless, while rest of 12 genes were multiexonic. Phylogenetic analysis of HSP70 gene family distinguished them into eight major evolutionary groups wherein members of group 1 were most divergent and quite dissimilar than from rest of the HSP70 sequences. Domain structure of all bovine HSP70 genes was conserved and three signature patterns HSP70_1, HSP70_2, and HSP70_3 were identified. HSPA8, HSP9, and HSPA1A showed comparatively higher expression in majority of tissues. Like humans, bovine HSP70 family was characterized by remarkable evolutionary diversity. The analysis also suggested resemblance of bovine HSP70 family to that of human compared to mouse. Overall, the study indicates the presence of diversity for structure, function, localization, and expression in the bovine HSP70 family chaperons which could form the basis to understand thermotolerance/adaptive changes in the bovines.

Mitochondrial sequence-based evolutionary analysis of riverine-swamp hybrid buffaloes of India indicates novel maternal differentiation and domestication patterns

In this study, mitochondrial D-loop sequence data on riverine, swamp and hybrid buffaloes from India have been generated and compared with other reported Indian riverine, Chinese and Bangladeshi swamp buffalo populations. Sequence analysis revealed the presence of 132 haplotypes, with a haplotype diversity of 0.9611 ± 0.0045 and a nucleotide diversity of 0.04801 ± 0.00126. For the first time, the existence of riverine-swamp hybrids among the Indian Chilika buffalo population has been recorded, having 49 chromosomes, which was also confirmed by mitochondrial haplotype sharing between Chilika and Indian swamp as well as Chinese swamp buffalo populations in the network analysis. Phylogenetic analysis documents the sharing of reported pre-domestication haplogroups 'SA1', 'SA2', 'SA3' and 'SB1' between the Chilika and swamp buffalo populations of India, China and Bangladesh, an indication of the migration of swamp buffaloes towards Bangladesh and adjoining lower parts of India and north towards Chinese domestication sites. The results have also been supplemented by multidimension scaling, grouping Indian and Chinese swamp buffaloes more closely together with Bangladeshi buffaloes, but into a separate quadrant, whereas Chilika grouped away from other riverine as well as swamp buffaloes. These findings thus confirm the previous reports that the northeast region of India, close to the Indo-China border, is the point of evolution of swamp buffaloes with multiple sites of domestication.

Assessment of genetic diversity and bottleneck in Purnathadi buffaloes using short tandem repeat markers

This study is the maiden attempt for genetic characterization of the Purnathadi, a phenotypically distinct buffalo population of the western Vidarbha region of Maharashtra and to explore genetic diversity using STR markers. A total of 48 unrelated Purnathadi buffaloes from the entire native tract were genotyped using a battery of 25 heterologous microsatellite markers. 5' end of forward primer of each microsatellite marker was labeled with one of the fluorescent dyes, viz., FAM (Blue), VIC (Green), NED (Yellow) or PET (Red) to assess the fragment length of genotyped PCR product with automated DNA sequencer (ABI 3100). 23 microsatellite loci (except ETH003 and ILSTS030) amplified successfully and adequately high allelic diversity (observed: 0.615 ± 0.043 and expected: 0.655 ± 0.037) was reported with 162 distinct microsatellite alleles. Sufficiently high Shannon index and PIC indicated the suitability of markers to evaluate genetic diversity in Purnathadi buffaloes. Within-population inbreeding estimates (F_IS) for Purnathadi buffalo ranged between -0.171 and 0.495 with global F_IS average of 5.9%. The outcome for IAM, TPM and test for mode shift revealed the absence of any recent bottleneck in Purnathadi buffalo. Pairwise F_ST (genetic differentiation) and gene flow between Purnathadi, Nagpuri and Marathwadi buffaloes were estimated using genotype data of 19 microsatellite markers. Lowest F_ST (0.031) was observed between Nagpuri and Purnathadi buffaloes with highest gene flow of 7.91% and highest F_ST (0.094) was between Purnathadi and Marathwadi populations. Present findings will definitely support in designing breeding plan for genetic improvement, as well as for developing conservation strategies of Purnathadi buffalo population. The comparative molecular study with other breeds of the regions is needed.

Genomic diversity and selection sweeps identified in Indian swamp buffaloes reveals it's uniqueness with riverine buffaloes

The present investigation was focused to study genomic diversity of Indian swamp buffalo populations through reduced representation approach (ddRAD). The heterozygosity (F_ST) among the swamp buffaloes was 0.11 between Assam and Manipuri; 0.20 between swamp (Manipuri) and riverine buffaloes; 0.30 between swamp (Manipuri) and cattle. The average observed and expected heterozygosity in swamp buffalo populations was 0.254 and 0.221 respectively. The Inbreeding coefficient (F_IS) value was 0.02 among the swamp buffaloes. PCA and structure analysis revealed Manipuri swamp buffalo was genetically distinct and closely related to Nagaland swamp buffalo and least to Assam swamp buffalo. Identification of selective sweeps revealed 1087 regions to have undergone selection related to immune response, adaptation and nervous system. A total of 3451 SSRs were identified in the genome of swamp buffaloes. The study evidenced the genomic diversity in the swamp buffalo populations and its uniqueness in comparison with riverine buffalo and cattle.

Comparative modeling and mutual docking of structurally uncharacterized heat shock protein 70 and heat shock factor-1 proteins in water buffalo

Aim:

In this study, a wide range of in silico investigation of Bubalus bubalis (BB) heat shock protein 70 (HSP70) and heat shock factor-1 (HSF1) has been performed, ranging from sequence evaluation among species to homology modeling along with their docking studies to decipher the interacting residues of both molecules.

Materials and Methods:

Protein sequences of BB HSP70 and HSF1 were retrieved from NCBI database in FASTA format. Primary and secondary structure prediction were computed using Expasy ProtParam server and Phyre2 server, respectively. TMHMM server was used to identify the transmembrane regions in HSP70. Multiple sequence alignment and comparative analysis of the protein was carried out using MAFFT and visualization was created using ESPript 3.0. Phylogenetic analysis was accomplished by COBALT. Interactions of HSP70 with other proteins were studied using STRING database. Modeller 9.18, RaptorX, Swiss-Modeller, Phyre2, and I-TASSER were utilized to design the three-dimensional structure of these proteins followed by refinement; energy minimization was accomplished using ModRefiner and SPDBV program. Stereochemical quality along with the accuracy of the predicted models and their visualization was observed by PROCHECK program of PDBsum and UCSF Chimera, respectively. ClusPro 2.0 server was accessed for the docking of the receptor protein with the ligand.

Results:

The lower value of Grand Average of Hydropathy indicates the more hydrophilic nature of HSP70 protein. Value of the instability index (II) classified the protein as stable. No transmembrane region was reported for HSP70 by TMHMM server. Phylogenetic analysis based on multiple sequence alignments (MSAs) by COBALT indicated more evolutionarily closeness of Bos indicus (BI) with Bos taurus as compared to BI and BB. STRING database clearly indicates the HSF1 as one of the interacting molecules among 10 interacting partners with HSP 70. The best hit of 3D model of HSP70 protein and HSF1 was retrieved from I-TASSER and Phyre2, respectively. Interacting residues and type of bonding between both the molecules which were docked by ClusPro 2.0 were decoded by PIC server. Hydrophobic interactions, protein-protein main-chain-side-chain hydrogen bonds, and protein-protein side-chain-side-chain hydrogen bonds were delineated in this study.

Conclusion:

This is the first-ever study on in silico interaction of HSP70 and HSF1 proteins in BB. Several bioinformatics web tools were utilized to study secondary structure along with comparative modeling, physicochemical properties, and protein-protein interaction. The various interacting amino acid residues of both proteins have been indicated in this study.

Identification of novel polymorphism in buffalo stanniocalcin-1 gene and its expression analysis in mammary gland under different stages of lactation

Stanniocalcin-1 (STC1) is secreted by the variety of tissues having a major role in the regulation of calcium ions in the involuting mammary gland. The present work aims to sequence and structural characterization as well as expression profiling of STC1 gene in buffalo. Polymorphism identified in the 3-untranslated region (UTR) was analysed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) genotyping in riverine and swamp buffaloes. Expression profiling of STC1 was performed in different lactation stages of mammary gland and peripheral blood mononuclear cells to study the impact of 3'-UTR polymorphism on its expression. Different polymorphic sites were detected in the entire coding and noncoding regions of riverine and swamp buffaloes, including two INDELs. An identified polymorphic nucleotide locus A324G, having target sites for two miRNAs, namely bta-miR-2382 and bta-miR-1343, reported in cattle, was genotyped by PCR-RFLP to reveal variable allelic distribution among swamp and riverine buffaloes. Gene expression profiling across buffalo mammary tissues representing different lactation stages showed maximum expression of the STC1 gene in the involuting mammary gland. Ruminants' specific genetic variation has been observed in STC1 and its implication in buffalo mammary gland involution as well as coregulation of gene expression through miRNA binding in the 3'-UTR is suggested.

Differential expression of cytokines in PBMC of Bos indicus and Bos taurus × Bos indicus cattle due to Brucella abortus S19 antigen

Brucellosis is the most dreadful disease among bovines, although breed differences have been observed in prevalence of disease, worldwide. In present study, antibody response and relative expression of proinflammatory cytokines was compared in Bos indicus (zebu) and Bos taurus × Bos indicus (crossbred) cattle vaccinated by live attenuated Brucella abortus S19 antigen. Six female calves (4-6 months age) of both groups were vaccinated with B.abortus S19 strain. Blood samples were collected before vaccination (0d) and 7^th (7d), 14^th (14d) and 28^th (28d) days after vaccination. Indirect ELISA showed high (p < .05) anti-Brucella antibody level after vaccination; with no significant difference between the groups. During Real-time expression, IFNγ, TNFα, IL6 and IL10 genes initially showed down regulation followed by upregulation in both the groups; however, the trend was much prominent in crossbreds. The expressions of IFNγ, TNFα and IL6, proinflammatory molecules important for initial containment of the Brucella were significantly (p < .01) higher in crossbred. The study showed that the Sahiwal cattle were less responsive to B.abortus S19 antigen than crossbreds, indicating its lower sensitivity to the Brucella, comparatively. In contrary, higher expression of the proinflammatory molecules in crossbreds could be important for containment of the organism during initial stage of infection.

Efficacy and tolerability of tremelimumab in patients with metastatic pancreatic ductal adenocarcinoma

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Background: Clinical activity and tolerability of the anti-CTLA-4 antibody, tremelimumab, has yet to be established in metastatic pancreatic ductal adenocarcinoma (mPDAC). In a Phase 2, multicenter, open label study (NCT02527434), tremelimumab was evaluated in pts with advanced solid tumors. We report a planned analysis of the safety and efficacy of tremelimumab monotherapy in a cohort of pts with mPDAC. Methods: Eligible pts were adults with histologically or cytologically confirmed mPDAC with tumor progression following prior standard first-line 5-FU- or gemcitabine-containing chemotherapy. Pts received tremelimumab 750 mg IV Q4W for 7 doses, followed by 750 mg Q12W for 2 doses, for up to a total of 12 mo (total 9 doses in 12 mo) or until disease progression or unacceptable toxicity. Pts were radiographically assessed Q6 wks relative to first dose. The primary endpoints were safety (evaluated by CTCAE v4.0) and objective response rate (ORR) by investigator assessments (evaluated by RECIST v1.1). Results: As of April 5, 2017, 20 mPDAC pts had received treatment and were evaluable for efficacy analysis. Median treatment duration was 1.8 mo. There were no observed objective responses (ORR 0%; 95% CI, 0.0, 16.8%). Of 20 pts, 2 were not evaluable and 18 had progressive disease (PD). Based on the full analysis set (N = 20), progression occurred in target lesions in 14 (70%), non-target lesions in 7 (35%), and new lesions in 13 (65%) pts (not mutually exclusive categories). At the time of progression, 11 (61%) pts were on treatment and 7 (39%) had discontinued treatment. Median overall survival was 4 mo (95% CI 2.83 - 5.42). Two (10%) pts were still in follow up at 12 mo after treatment initiation. Treatment-related AEs (trAEs) occurred in 14 pts (70%); grade ≥3 trAEs occurred in 6 pts (30%). Three pts (15%) discontinued therapy due to trAEs. There were no treatment-related deaths. Conclusions: Tremelimumab monotherapy did not appear to be active in mPDAC pts who had tumor progression following prior standard first-line 5-FU- or gemcitabine-containing chemotherapy. Clinical trial information: NCT02527434.

PCR-SSCP analysis of MDGI gene and its association with milk production traits in river buffalo (Bubalus bubalis)

In this study, we investigated the genetic variation within 3'UTR of Mammary-Derived Growth Inhibitor (MDGI) gene of buffalo using PCR-SSCP and sequencing; and also analyzed association of polymorphism with the milk production traits. The study revealed two conformational patterns, 'A' and 'B' among 234 Mehsana buffaloes maintained with their records in the field and at farm. The frequency of SSCP variant 'A' was found to be invariably high in the buffalo population under study. Further, association analysis of SSCP variants with various milk production and milk quality traits indicated no significant effect on any of the traits investigated. Sequencing of SSCP variant 'A' showed homozygous G/G and A/A and 'B' had heterozygous G/C and A/G at positions +124 and +140 respectively, in the 3'UTR of buffalo MDGI. The preliminary results showed the substantial variations in the distribution of SSCP variants' frequencies within Mehsana buffaloes, however these variants had non-significant association with milk yield, fat yield and fat percentage in Mehsana buffaloes.

Identification of genetic variation in NOD-like receptor 2 gene and influence of polymorphism on gene structure and function in buffalo (Bubalus bubalis)

Nucleotide-binding oligomerization domain (NOD)-like receptor 2 is one of the important mediators of innate as well as adaptive immune response to microbial infections. In this study, NOD-like receptor-2 was characterized by determining the full gene sequence and analyzing genetic diversity in Indian buffaloes. Sequence analysis of buffalo NOD2 revealed 3042 nucleotides long ORF, encoding 1013 amino acids from 12 exons. Domain structure analysis indicated existence of 8 leucine-rich repeat (LRR) domains in buffalo, cattle, sheep and mouse, along with central NACHT/NOD domain and two N-terminal CARD domains. Comparative sequence analysis among different buffalo breeds identified 46 polymorphic sites in NOD2 gene. Among coding region SNPs, 10 were non-synonymous, 7 synonymous and 3 were present in 5'UTR. Genotyping of two nsSNPs, revealed significant differences in the allele frequencies, distinguishing swamp and riverine buffaloes, having different utilities. Association analysis with mastitis in dairy buffaloes indicated significant variation in allelic frequencies at G1135A locus, between mastitis affected and non-affected animals. Further, NOD2 gene expression was quantified in different riverine buffalo tissues, using real-time PCR and lymph node displayed highest expression, compared to others organs included in the study. Overall, the study revealed buffalo NOD2 gene attributes, important to understand species specific immune response in ruminants.

Expression Analysis of Genes Associated with Prolificacy in FecB Carrier and Noncarrier Indian Sheep

The effect of FecB mutation on the gene expression in FecB carrier and noncarrier estrous synchronized ewes, has been analyzed. For this study the whole ovarian tissues and Graafian follicles were collected from estrus synchronized FecB carrier Garole, and non-carrier Deccani Indian sheep, showing remarkable differences in the numbers of preovulatory follicles among two groups. Eleven potential candidate genes (BMP15, GDF9, BMP4, BMP7, BMPR1B, BMPR1A, SMAD9, LHCGR, FSHR, IGF1R, and STAT5) were selected for their expression analysis by SybrGreen based real-time PCR, across ovaries and Graafian follicles of different fecundity groups, for having better insights into the effect of FecB genotypes on follicular development. Variable expression was observed for almost all the genes included in the present study among high and low fecundity groups that was most significant for the BMP7, BMP4, LHCGR, and FSHR transcripts in the ovarian follicles of high and low fecundity ewes, indicating their importance in governing the fecundity in FecB carrier, Indian Garole sheep. BMP4 expression among the genes studied was significantly higher in FecB carrier Garole sheep. This study confirms the changes in mRNA expression of the genes implicated in follicular development in FecB carrier and noncarrier Indian sheep breeds.

Molecular Characterization of Buffalo Haptoglobin: Sequence Based Structural Comparison Indicates Convergent Evolution Between Ruminants and Human

Haptoglobin (Hp) protein has high affinity for hemoglobin (Hb) binding during intravascular hemolysis and scavenges the hemoglobin induced free radicals. Earlier reports indicate about uniqueness of Hp molecule in human and cattle, but in other animals, it is not much studied. In this paper, we characterized buffalo Hp molecule and determined its molecular structure, evolutionary importance, and tissue expression. Comparative analysis and predicted domain structure indicated that the buffalo Hp has an internal duplicated region in α-chain only similar to an alternate Hp2 allele in human. This duplicated part encoded for an extra complement control protein CCP domain. Phylogenetic analysis revealed that buffalo and other ruminants were found to group together separated from all other non-ruminants, including human. The key amino acid residues involved in Hp and Hb as well as Hp and macrophage scavenger receptor, CD163 interactions in buffalo, depicted a significant variation in comparison to other non-ruminant species. Constitutive expression of Hp was also confirmed across all the vital tissues of buffalo, for the first time. Results revealed that buffalo Hp is both structurally and functionally conserved, having internal duplication in α-chain similar to human Hp2 and other ruminant species, which might have evolved separately as a convergent evolutionary process. Furthermore, the presence of extra Hp CCP domain possibly in all ruminants may have an effect during dimerization of molecule in these species.

POLYMORPHISM IN THE CODING REGION SEQUENCE OF GDF8 GENE IN INDIAN SHEEP

The present study was undertaken to identify polymorphism in the coding sequence of GDF8gene across indigenous meat type sheep breeds. A 1647 bp sequence was generated, encompassing 208 bp of the 5'UTR, 1128 bp of coding region (exon1, 2 and 3) as well as 311 bp of 3'UTR. The sheep and goat GDF8 gene sequences were observed to be highly conserved as compared to cattle, buffalo, horse and pig. Several nucleotide variations were observed across coding sequence of GDF8 gene in Indian sheep. Three polymorphic sites were identified in the 5'UTR, one in exon 1 and one in the exon 2 regions. Both SNPs in the exonic region were found to be non-synonymous. The mutations c.539T > G and c.821T > A discovered in this study in the exon 1 and exon 2, respectively, have not been previously reported. The information generated provides preliminary indication of the functional diversity present in Indian sheep at the coding region of GDF8gene. The novel as well as the previously reported SNPs discovered in the Indian sheep warrant further analysis to see whether they affect the phenotype. Future studies will need to establish the affect of reported SNPs in the expression of the GDF8 gene in Indian sheep population.

MARKER ASSISTED EVALUATION OF MORPHOLOGICAL AND GENETIC ATTRIBUTES OF SUB-POPULATIONS OF NILI-RAVI BUFFALO: A VULNERABLE DAIRY TYPE RIVERINE BREED OF INDIA

In the present study, we report the distribution of true to type and atypical Nili-Ravi buffalo, a vulnerable dairy type riverine breed of North India and its underlying genetic structure. Out of total investigated buffaloes 73.5% had bilateral wall eyes while 5.4% had unilateral wall eyes and 21.1% had no wall eyes. 41.15% of Nili-Ravi buffaloes maintained in the breeding farm were having typical true to the type characteristics (both eyes walled, white markings in forehead, muzzle/chin, all the four legs and tail) while only 28.5% of Nili-Ravi buffaloes were true to the type under field conditions. Genotypic data were generated in four groups of Nili-Ravi buffalo (FMTNR--Typical Nili-Ravi from farm; FMANR--Atypical Nili-Ravi from farm; FDTNR--Typical Nili-Ravi from field; FDANR--Atypical Nili-Ravi from field) at 16 microsatellite loci. Comparative genetic analysis of various groups of Nili-Ravi buffaloes with Murrah revealed significant between group differences with an estimated global F(ST) of 0.063. Pair-wise F(ST) values ranged from 0.003 (between FDTNR and FDANR) to 0.112 (between FMTNR and FDTNR). Phylogenetic analysis and multi-dimensional scaling revealed clustering of FDTNR and FDANR together while FMTNR and FMANR clustered separately with Murrah in between farm and field Nili-Ravi buffaloes. Based on the results, the paper also proposes three pronged strategy for conservation and sustainable genetic improvement of Nili-Ravi buffalo in India.

Genetic analysis of river, swamp and hybrid buffaloes of north-east India throw new light on phylogeography of water buffalo (Bubalus bubalis)

This study analysed buffaloes from north-east India and compared their nuclear and mitochondrial DNA variations with buffaloes of mainland India, China, Mediterranean and South-East Asia. Microsatellite genotypes of 338 buffaloes including 210 from six north-east Indian buffalo populations and three mainland Indian breeds were analysed to evaluate their genetic structure and evolutionary relationships. Phylogenetic analysis and multidimensional scaling plot of pairwise FST revealed the clustering of all swamp-type buffaloes of north-east India with Lower Assamese (significantly hybrid type) buffaloes in one plane and all the mainland river buffaloes in another plane while the upper Assamese buffaloes being distinct from both these clusters. Analysis of mtDNA D-loop region of 530-bp length was performed on 345 sequences belonging to 23 buffalo populations from various geographical regions to establish the phylogeography of Indian water buffalo. The swamp buffaloes of north-east India clustered with both the lineages of Chinese swamp buffalo. Multidimensional scaling display of pairwise FST derived from mitochondrial DNA data showed clustering of upper Assamese, Chilika and Mediterranean buffaloes distinctly from all the other Indian buffalo populations. Median-joining network analysis further confirmed the distinctness and ancestral nature of these buffaloes. The study revealed north-east region of India forming part of the wider hybrid zone of water buffalo that may probably extend from north-east India to South-East Asia.

Expression profiling of glucose transporter 1 (GLUT1) and apoptotic genes (BAX and BCL2) in milk enriched mammary epithelial cells (MEC) in riverine buffalo during lactation

Lactation is an important physiological process in dairy animals. During lactation, up to 85% of the body glucose is directed toward the mammary glands for milk synthesis. Studies related to lactation physiology are generally carried out on mammary biopsies, which may adversely affect animal health. In the present study, milk enriched MEC were used to study the expression pattern of GLUT1 and apoptotic genes (BAX and BCL2) across different stages of lactation in riverine buffalo in relation to milk yield. MEC were enriched from milk using cytokeratin-8 antibodies coated magnetic beads. Total RNA isolated from enriched MEC showed significant correlation (r(2) = 0.92 ± 0.02) with the milk yield at different stages of lactation. GLUT1 expression pattern correlated with the milk yield as highest GLUT1 expression (4.68 ± 0.79) was observed during peak-lactation (90 days post-parturition), whereas low GLUT1 expression (1.01 ± 0.1, 15 d; 0.71 ± 0.03, 30 d) was observed during early lactation. The BAX/BCL2 ratio was high (1.02 ± 0.2, 15 d; 0.94 ± 0.06, 30 d) during the early phase of lactation, indicating high rate of apoptosis, whereas low BAX/BCL2 ratio (0.25 ± 0.03, 60 d; 0.42 ± 0.04, 90 d) was observed during mid-lactation coinciding with the increase in RNA concentration and milk yield. Highest BAX/BCL2 ratio (1.41 ± 0.3, 120 d; 4.02 ± 0.6, 240 d) was observed during late lactation i.e., 240 days, which was also reflected as decline in milk yield and RNA concentration. Also, BAX/BCL2 ratio in milk enriched MEC was in accordance with RNA concentration in MEC and milk yield at different phases of lactation. Our study showed that expression pattern of genes under study (GLUT1, BAX, and BCL2) in milk enriched MEC correlated well with important physiological properties such as milk yield in buffalo.

Analysis of genetic variations across regulatory and coding regions of kappa-casein gene of Indian native cattle (Bos indicus) and buffalo (Bubalus bubalis)

The promoter region of kappa-casein (κ-CN) gene in Indian native cattle and buffalo breeds was sequenced and analyzed for nucleotide variations. Sequence comparison across breeds of Indian cattle revealed a total of 7 variations in the promoter region, of which − 515 G/T, − 427 C/T, − 385 C/T, − 283 A/G and − 251 C/T were located within consensus binding sites for octamer-binding protein (OCT1)/pregnancy specific mammary nuclear factor (PMF), activator protein-2 (AP2), hepatocyte nuclear factor (HNF-1) and GAL4 transcription factors (TFs), respectively. These variations might be involved in gain or loss of potential transcription factor binding sites (TFBSs). Unlike the other 4 variants, the − 283 (A/G) variant located within HNF-1 TFBS was specific to Indian cattle as this change has not been observed in the Bos taurus sequence. Other TFBSs viz., MGF, TBP, NF-1, milk box and C/EBP were conserved across species. For the Indian native buffalo breeds, only 3 changes were identified in the promoter region; − 305 (A/C), − 160 (T/C) and − 141 (A/G) and most of the TFBSs were found to be conserved. However, deletion of two adjacent nucleotides located in and around binding site for C/EBP TF was identified in buffalo when compared with promoter sequence of bovine κ-CN. For κ-CN of Indian native cattle, a strong linkage disequilibrium (LD) was observed for variations 515 G/T, − 427 C/T and − 385 C/T in the promoter region; and for variations at codons 136 and 148 of exon-IV. Further, among intragenic haplotypes, variation − 427 C/T was found to be in LD with variations at codons 136 and 148. The information generated in the present work provides comprehensive characterization of κ-CN gene promoter and coding regions in Indian cattle and buffaloes and reported variations could become important candidates for carrying out further research in dairy traits.

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The κ-casein gene (κ-CN) and its promoter region was sequence characterized in 15 Indian native cattle and 8 buffalo breeds.

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Among the identified variations, four were located within TFBSs in Indian cattle, while all TFBSs were conserved in buffaloes.

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The κ-CN CDS was highly conserved with only 3 and 2 non-synonymous changes for Indian cattle and buffaloes, respectively.

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Across promoter and CDS, − 427 C/T was found to be in LD with variation at codons 136 and 148.

Classical swine fever in the pygmy hog

The pygmy hog is a rare, small and highly endangered mammal belonging to the Suidae family, and it is presently found only in the Assam state of India. While investigating the cause of death of pygmy hogs housed at a conservation centre for captive breeding and research at Basistha, Assam, it was confirmed that they were susceptible to and died as a result of contracting classical swine fever (CSF), caused by CSF virus (CSFV), which is a highly infectious endemic disease of domestic pigs in India. The post-mortem findings and serum CSFV-specific antibody titres, along with the isolation of CSFV from two pygmy hogs, and further confirmation by CSFV genomic E2 and 5' untranslated region (UTR) gene amplification in PCR (polymerase chain reaction), clearly established the cause of death of the pygmy hogs. Further, on phylogenetic analysis, the pygmy hog CSFV 5' UTR sequences were grouped in the genotype 1.1 cluster of Indian CSFVs, and hence the strains causing infection were closely related to CSFV isolates circulating in domestic pigs. Therefore, the occurrence of CSF in this endangered species may pose a potent threat to their existence unless properly controlled, and thus it needs urgent attention. To the authors' knowledge this is the first report on CSF in pygmy hogs.

Genetic polymorphisms in the bovine toll-like receptor 4 (TLR4) and monocyte chemo attractant protein-1(CCL2) genes: SNPs distribution analysis in Bos indicus Sahiwal cattle breed

Toll-like receptor 4 gene (TLR4) that recognizes the Gram negative bacterial ligand LPS was sequenced in the Bos indicus Sahiwal cattle breed. Ninety four single nucleotide polymorphisms (SNPs) were detected within 10.8 kb gene region. Seventeen of the SNPs were in the coding regions and the one at position 9589(A > G) in exon3 resulted in an amino acid change from Valine to Isoleucine. These SNPs led to generation of 27 TLR4 gene haplotypes. All the Sahiwal animals studied presently showed the occurrence of the genotype CC at gene position 9662, which codes for the amino acid threonine at position 674 of the TLR4 protein, and which had been reported to be associated with lower somatic cell score and, therefore, a lower susceptibility to mastitis, in Taurus cattle. This nucleotide configuration of the Toll-like receptor 4 gene of the Bos indicus Sahiwal cattle breed could possibly indicate toward a lower susceptibility to mastitis in the Sahiwal animals. Monocyte chemo-attractant protein-1 (CCL2) gene encoding for small inducible cytokine A2 that belongs to the CC chemokine family was also sequence characterized in these Sahiwal animals. The CCL2 gene was observed to have 12 polymorphic sites in 3.3 kb region of which one SNP at position 2500 (A > G) in exon 3 resulted in amino acid change from Valine to Isoleucine at position 46 of the mature CCL2 peptide. Seventeen haplotypes of the CCL2 gene were predicted corresponding to 12 genotypes detected.

Genetic diversity within 5'upstream region of Toll-like receptor 8 gene reveals differentiation of riverine and swamp buffaloes

In this study the nucleotide diversity in the 5'untranslated region (UTR) of TLR8 gene in riverine as well as swamp buffaloes has been described. Analysis of the 5'UTR of TLR8 gene showed presence of two SNPs in this region, g.-139G>T and g.-128A>G. A PCR-RFLP assay designed for genotyping of g.-139G>T SNP across 667 samples from 2 buffalo populations revealed a striking difference in allele frequency distribution across the swamp and riverine buffaloes. The frequency of T allele was higher in swamp buffalo as compared to riverine buffalo, ranging from 0.71 to 1. The G allele on the other hand exhibited a higher frequency across all the Indian riverine buffalo breeds/populations. The principal component analysis revealed separate clusters for the riverine and swamp buffaloes, as expected; however, the riverine type Assamese buffalo population of eastern India formed a distinct cluster. Since most of the buffalo populations in the eastern region are swamp type, this demarcation may be related to the difference in immune response in riverine and swamp buffaloes. These preliminary results indicate that the genetic variation observed in 5'upstream region of TLR8 gene, which differentiates swamp and riverine buffalo, needs to be further explored for association with disease susceptibility in buffalo, an important dairy and meat animal of Southeast Asia.

Caprine Toll-like receptor 8 gene sequence characterization reveals close relationships among ruminant species

TLR8 mediates antiviral immunity by recognizing ssRNA viruses and triggers potent antiviral and antitumor immune responses. In this study, approximately 3.5 Kb nucleotide sequence data of caprine TLR8 gene were generated from one sample each of twelve different Indian goat breeds belonging to different geographical regions. Cloning and characterization of cDNA synthesized from RNA purified from goat spleen revealed TLR8 ORF to be of 3102 nucleotides long coding for 1033 amino acids similar to other ruminant species, that is sheep, buffalo and cattle. The sequence analysis at nucleotide level revealed goat TLR8 to be closer to buffalo sharing 99.6% homology, followed by cattle and sheep. Simple Modular Architecture Research Tool (SMART) used for the structural analysis of goat TLR8 showed the presence of 16 leucine-rich repeats (LRRs) along with single Toll/interleukin-1 receptor (TIR) domain. TIR domain when compared with other livestock species was found to be conserved in ruminant species goat, sheep, cattle and buffalo. The phylogenetic analysis also revealed grouping of all ruminant species together, goat being closer to buffalo followed by cattle and sheep. Total 4 polymorphic sites were observed in TLR8 gene of one specimen goat representing each of 12 different breeds studied, all of which were synonymous and present within the coding region. Of these 4 SNPs, two were in ectodomains, one in TIR domain and one was found to be present in transmembrane domain. PCR-RFLP genotyping of two of the SNPs indicated variations in allele frequencies among different goat breeds. The expression profiling in 13 tissues of goat showed maximum expression of TLR8 gene in kidney followed by spleen, lung and lymph node. Overall, our results indicate conservation of TLR8 gene among the ruminant species and low variation within Indian goat breeds.

Novel polymorphisms in UTR and coding region of inducible heat shock protein 70.1 gene in tropically adapted Indian zebu cattle (Bos indicus) and riverine buffalo (Bubalus bubalis)

Due to evolutionary divergence, cattle (taurine, and indicine) and buffalo are speculated to have different responses to heat stress condition. Variation in candidate genes associated with a heat-shock response may provide an insight into the dissimilarity and suggest targets for intervention. The present work was undertaken to characterize one of the inducible heat shock protein genes promoter and coding regions in diverse breeds of Indian zebu cattle and buffaloes. The genomic DNA from a panel of 117 unrelated animals representing 14 diversified native cattle breeds and 6 buffalo breeds were utilized to determine the complete sequence and gene diversity of HSP70.1 gene. The coding region of HSP70.1 gene in Indian zebu cattle, Bos taurus and buffalo was similar in length (1,926 bp) encoding a HSP70 protein of 641 amino acids with a calculated molecular weight (Mw) of 70.26 kDa. However buffalo had a longer 5' and 3' untranslated region (UTR) of 204 and 293 nucleotides respectively, in comparison to Indian zebu cattle and Bos taurus wherein length of 5' and 3'-UTR was 172 and 286 nucleotides, respectively. The increased length of buffalo HSP70.1 gene compared to indicine and taurine gene was due to two insertions each in 5' and 3'-UTR. Comparative sequence analysis of cattle (taurine and indicine) and buffalo HSP70.1 gene revealed a total of 54 gene variations (50 SNPs and 4 INDELs) among the three species in the HSP70.1 gene. The minor allele frequencies of these nucleotide variations varied from 0.03 to 0.5 with an average of 0.26. Among the 14 B. indicus cattle breeds studied, a total of 19 polymorphic sites were identified: 4 in the 5'-UTR and 15 in the coding region (of these 2 were non-synonymous). Analysis among buffalo breeds revealed 15 SNPs throughout the gene: 6 at the 5' flanking region and 9 in the coding region. In bubaline 5'-UTR, 2 additional putative transcription factor binding sites (Elk-1 and C-Re1) were identified, other than three common sites (CP2, HSE and Pax-4) observed across all the analyzed animals. No polymorphism was found within the 3'-UTR of Indian cattle or buffalo as it was found to be monomorphic. The promoter sequences generated in 117 individuals showed a rich array of sequence elements known to be involved in transcription regulation. A total of 11 nucleotide changes were observed in the promoter sequence across the analyzed species, 3 of these changes were located within the potential transcription factor binding domains. We also identified 4 microsatellite markers within the buffalo HSP70.1 gene and 3 microsatellites within bovine HSP70.1. The present study identified several distinct changes across indicine, taurine and bubaline HSP70.1 genes that could further be evaluated as molecular markers for thermotolerance.

Detection of polymorphism and sequence characterization of Toll-like receptor 7 gene of Indian goat revealing close relationship between ruminant species

In this study, approximately 3.4 kb nucleotide sequence of caprine TLR7 (Toll-like receptor 7) gene was generated from twelve different Indian goat breeds belonging to different geographical regions. Goat TLR7 gene ORF (Open Reading Frame) was found to be 3141 nucleotides long coding for 1046 amino acids similar to sheep. The sequence analysis at nucleotide level revealed goat TLR7 having 99.5% homology with sheep, followed by other livestock species. Simple Modular Architecture Research Tool (SMART) was used for the structural analysis of goat TLR7 that showed the presence of 22 leucine rich repeats (LRRs) along with single Toll/interleukin-1 receptor (TIR) domains. TIR domain, when compared, was found to be similar in ruminant species, goat, sheep, cattle, and buffalo. The phylogenetic analysis also revealed grouping of all ruminant species together, goat being closer to sheep followed by cattle and buffalo. A total of 22 polymorphic sites were observed in TLR7 gene of 24 goats representing 12 different breeds, out of which 19 were present within the coding region and three in 3'UTR. Out of the seven nonsynonymous SNPs, two were in ectodomains and one in TIR domain. Overall our results indicate substantial variation within goat TLR7 gene, which could be exploited for association with disease susceptibility.

Sequence characterization of river buffalo Toll-like receptor genes 1-10 reveals distinct relationship with cattle and sheep

The present study was undertaken to characterize the full-length transcripts of Toll-like receptor (TLR) genes 1-10 of river buffalo. The conceptualized amino acid identity of bubaline TLRs ranged between 86% to 100% with ruminants, while it ranged between 45% to 91% with other vertebrate species. Simple modular architecture tool (SMART) analysis revealed the presence of TIR domains and varying numbers of leucine-rich repeat motifs in all the buffalo TLRs. With respect to TIR domains, TLRs 1, 2 and 3 of river buffalo were found to have 99.3% identity with cattle and 100% identity of TLRs 4, 6 and 10 with sheep. Phylogenetic analysis of TLRs of buffalo and different vertebrate species revealed the clustering of major TLR gene subfamilies with high bootstrap values. The evolutionary relationship between buffalo and other ruminant species was found to vary among different TLRs. In order to understand the relationship between TLRs of different ruminant species, multidimensional scaling (MDS) analysis of pairwise amino acid differences between different species within each TLR was performed. Buffalo and cattle were found to be closely related only with respect to TLRs 1, 2 and 7, while buffalo and sheep were found to be clustering together with respect to TLRs 3, 6, 8 and 10. The distinct relationship of bubaline TLRs with cattle and sheep revealed the possible differences in the pathogen recognition receptor systems in these animals and consequently the differences in their susceptibility/resistance to various invading organisms.

Power of exclusion of 19 microsatellite markers for parentage testing in river buffalo (Bubalus bubalis)

In the present study, 19 microsatellite markers were assessed for their power of exclusion to test parentage in river buffalo. Microsatellite genotypes of 216 unrelated buffaloes belonging to five different breeds were utilized for the study. The probabilities of exclusion were calculated for three hypothetical situations viz. paternity testing (PE1), one parental genotype unavailable (PE2) and exclusion of both parents i.e. substituted offspring (PE3). The mean probability of exclusion across 19 investigated markers in buffalo was 0.578 (PE1), 0.405 (PE2) and 0.764 (PE3) respectively. The probability of exclusion for paternity (PE1) ranged between 0.297 and 0.814 across different markers. The exclusion probability for the cases one parent unavailable (PE2) and substituted offspring (PE3) varied from 0.143 to 0.688 and 0.465 to 0.946 respectively. Polymorphism information content and expected heterozygosity were found to have significantly high correlation with probability of exclusion of microsatellite markers. The cumulative PE1 of nine marker loci was estimated to be 0.9999 while in case of absence of one of the parental genotypes, a minimum of 11 markers were required to achieve a cumulative PE2 of 0.999. In conclusion, the present study proposes two multiplex sets with four and five markers respectively for routine parentage testing in buffalo and an additional set of four markers for doubtful cases of paternity.

Population structure and phylogeography of Toda buffalo in Nilgiris throw light on possible origin of aboriginal Toda tribe of South India

We report the genetic structure and evolutionary relationship of the endangered Toda buffalo of Nilgiris in South India with Kanarese and two other riverine buffalo breeds. The upgma phylogeny drawn using Nei's distance grouped South Kanara and Toda buffaloes at a single node while Marathwada and Murrah together formed a separate node. Principal component analysis was performed with pairwise interindividual chord distances which revealed clustering of Murrah and Marathwada buffaloes distinctly, while individuals of Toda and South Kanara breeds completely intermingled with each other. Furthermore, there were highly significant group variances (p < 0.01) when the breeds were grouped based on phylogeny, thus revealing the existence of cryptic genetic structure within these buffalo breeds. To know the evolutionary relationship among these breeds, 537-bp D-loop region of mitochondrial DNA was analysed. The phylogenetic analysis of mtDNA haplotypes following NJ algorithm with Chinese swamp buffalo as outgroup revealed a major cluster that included haplotypes from all the four investigated breeds and two minor clusters formed by South Kanara and Toda haplotypes. Reduced median network analysis revealed haplotypes of South Kanara and Toda to be quite distinct from the commonly found haplotypes indicating that these might have been ancestral to all the present-day haplotypes. Few mutations in two of the haplotypes of South Kanara buffalo were found to have contributed to ancestral haplotypes of Toda buffalo suggesting the possible migration of buffaloes from Kanarese region towards Nilgiris along the Western Ghats. Considering the close social, economic and cultural association of Todas with their buffaloes, the present study supports the theory of migration of Toda tribe from Kanarese/Mysore region along with their buffaloes.

Short tandem repeat based analysis of genetic variability in Kanarese buffalo of South India

The goal of the present study was assessing genetic diversity within Kanarese buffalo, the dual purpose breed of South India. A total of 48 unrelated animals were genotyped at 23 short tandem repeat (STR markers) loci. The total number of observed alleles was 180 with a mean of 7.83 per locus, which varied from 3 to 12 across different loci. The mean observed and expected heterozygosity in South Kanara buffaloes was estimated to be 0.518 and 0.712 respectively. Within population inbreeding estimate (F(IS)) was significantly positive in most of the investigated loci which resulted in significant deviation from Hardy-Weinberg equilibrium at 19 of 23 loci analyzed. Evaluation of South Kanara buffalo population for mutation drift equilibrium revealed no significant heterozygosity excess under three different models of evolution viz. infinite alleles model (IAM), stepwise mutation model (SMM) and two phase model (TPM), thus indicating the absence of any recent genetic bottleneck. The results of the present study will help in formulating rational breeding strategies as well as conservation of this important germplasm.

5'-UTR-based phylogenetic analysis of Classical swine fever virus isolates from India

Classical swine fever (CSF) caused by Classical swine fever virus (CSFV) is a globally significant disease of pigs. Genetic typing of CSFV isolates can help in understanding the epidemiology of disease and trace down the source of outbreak. 5'-UTR sequence analysis and subsequent genetic classification of nine CSFV field isolates from India indicated that 3 isolates belonged to genotype 2.1 and were closely related to European CSFV strains. The remaining 6 isolates belonged to genotype 1 that contained old and new strains. However, the genotype 2.1 group consisted of recent field isolates only. The study showed circulation of both genotypes 1 and 2.1 in north-eastern part of India.

Sequence analysis of the S10 gene of six Bluetongue Virus isolates from India

Bluetongue Virus (BTV) genome segment 10 (S10)-based phylogenetic studies are important in understanding the BTV evolution. S10 gene-based phylogenetic analysis grouped six different BTV isolates (BTV serotype 1, 18 and 23) from India in subclade A1 and showed closer relationship with BT viruses from Mediterranean Basin. Indian BTV serotypes 18 and 23 formed a single cluster distinct from BTV serotype 1 isolates and were evolved from BTV from China, Indonesia and Australia. The overall S10 sequences of BTV isolates from India were largely conserved (>95.7% homology) and were distinct from other BT viruses of the world.

Genetic diversity and bottleneck analysis of Nagpuri buffalo breed of India based on microsatellite data

In this study, 25 heterologous bovine microsatellite markers have been used for the assessment of genetic diversity in Nagpuri buffalo, an important breed of Central India. For this, 48 DNA samples of unrelated individuals of Nagpuri buffalo were PCR amplified and microsatellite alleles were resolved in 6% denaturing, silver stained Urea-PAGE gel. Genotypic status of individuals at each locus was identified manually and data analysis carried out using POPGENE software. Observed number of alleles varied from 2 (ILSTS073 locus) to 8 (HEL13 & ILSTS058 loci) with a mean of 5.24 alleles per locus. Moderate level of heterozygosity (0.45) indicated sufficient genetic diversity existing in this buffalo population. PIC values for the microsatellite loci analysed, ranged from 0.10 (ILSTS019 locus) to 0.81 (ILSTS058 locus) with a mean of 0.53. No shift in the frequency distribution of alleles and a normal L-shaped curve indicated non-existence of any bottleneck in Nagpuri. The study thus highlights the usefulness of heterologous bovine microsatellite markers to assess the genetic variability in buffalo breeds as well. Also various diversity indices suggest sufficient genetic variability within Nagpuri buffalo that can be utilized as initial guidelines for future breeding strategies and conservation.

Isolation and sequence characterization of mammary derived growth inhibitor gene of riverine buffalo (Bubalus bubalis)

In this study, attempts have been made to identify and characterize water buffalo (Bubalus bubalis) mammary derived growth inhibitor (MDGI) gene, isolated from a mammary gland cDNA library of lactating buffalo. The complete MDGI cDNA was of 698 nucleotides, consisting 61 nucleotides in 5' UTR, coding region of 402 nucleotides, and 235 nucleotides representing the 3' UTR. Comparison of nucleotide and deduced amino acid sequence data with that of MDGI/fatty acid binding protein (FABP) of other species shows three buffalo specific nucleotide changes while seven nucleotide changes were common to cattle and buffalo. Buffalo and cattle MDGI had 100% amino acid sequence similarity, which also shared three amino acid changes: 34 (Ala-Gly), 109 (Leu-Met), and 132 (Glu-Gln) as compared to other species. Comparison with FABPs reported from other cattle tissues revealed highest amino acid sequence similarity with FABP-heart (100%) and least with FABP-liver (20.5%). Phylogenetic analysis revealed cattle MDGI to be closest to buffalo, while mouse MDGI was distantly placed, whereas different tissue derived FABPs of cattle showed FABP-heart closest and FABP-epidermis most distantly placed from buffalo MDGI. This report also differs from the earlier findings that MDGI is intermediate of FABP-heart and adipose.

Bluetongue virus induces apoptosis in cultured mammalian cells by both caspase-dependent extrinsic and intrinsic apoptotic pathways

Bluetongue virus (BTV) causes haemorrhagic disease in sheep and induces death in cultured mammalian cells. In the present study, BTV-induced apoptotic pathways in Vero cells were elucidated. Cells infected with BTV at 0.1 m.o.i underwent DNA fragmentation and membrane blebbing within 48 h postinfection. BTV-induced apoptosis was blocked by the pan-caspase inhibitor, z-VAD-FMK. Immuno-blotting using anti-caspase-8 and -9 antibodies detected the activation of the respective caspases. Flow cytometry analyses following 3, 3' dihexyloxacarbocyanine iodide staining revealed the loss of mitochondrial membrane potential. Our study confirms the involvement of both caspase-dependent extrinsic and intrinsic pathways of apoptosis in BTV-infected cells.

Sequence analysis of VP7 gene of Indian bluetongue virus serotype-23 shows its close phylogenetic relationship to Australian and Chinese serotypes

Bluetongue, an arthropod borne viral disease of wild and domestic ruminants, causes heavy economic losses throughout the world. In the present study, full-length VP7 gene of Indian bluetongue virus (BTV) serotype 23 was sequenced and compared with prototype strains of BTV reported from different countries. Nucleotide sequence analysis of VP7 gene revealed Indian BTV serotype 23 to have 1154 nucleotides with the deletion of two nucleotides at 3' non-coding region and a unique amino acid change 211S-N. The Indian virus also demonstrated a maximum similarity of 94.2% with Australian serotype 1 and a minimum similarity of 67.4% with Australian serotype 15. However, at deduced amino acid level, it had maximum similarity of 99.7% and a minimum of 82.5% with Chinese serotypes 1, 2 and 4 and Australian serotype 15, respectively. Deduced amino acid sequence analysis of putative receptor binding domain (121-249) revealed all the nine hydrophilic domains to be conserved across the serotypes. Functional motifs present in VP7 protein were also conserved in almost all the BTV serotypes including Indian serotype 23. Phylogenetic analysis based on VP7 gene sequence revealed Indian BTV serotype 23 segregating into a monophyletic group along with Australian serotype 1 and Chinese serotypes 1, 2 and 4, indicating its close evolutionary relationship with these Australian and Chinese serotypes.

Differential detection of Newcastle disease virus strains by degenerate primers based RT-PCR

Degenerate primers based RT-PCR (previously described by [Avian Dis 26 (1997) 837]) has been used for the detection and differentiation of Newcastle disease (ND) viruses. Two sets of primers (A+B and A+C), with common forward primer and distinct reverse degenerate primers, designed from fusion protein gene encoding for cleavage site, could differentiate virulent and avirulent Newcastle disease viruses (NDV). Both sets of primers amplified "F" gene sequence of virulent (velogenic and mesogenic) viruses, whereas in avirulent strains, amplification was only with primer set A+C. Total 10 NDV isolates and two clinical samples including both known and unknown pathotypes, were checked. Based on amplification results 5 viruses were found to be virulent type and 6 as avirulent with one of the two clinical samples, earlier positive by RT-PCR using non-degenerate "F" gene specific primers was found negative in this study. The technique has been found to be a simple and quick for the detection and differentiation of virulent and avirulent NDV, which is important for control of the disease in the events of the outbreaks.

Characterisation of fowl adenoviruses from chickens affected with infectious hydropericardium during 1994-1998 in India

In the present study characterisation has been done for six group I fowl adenoviruses (FAV) isolated from outbreaks of infectious hydropericardium (IHP) of chickens that occurred in different states/regions of India during the years 1994-98. These six viruses were identified as FAV serotype 4 by virus neutralisation and restriction endonuclease analyses. Antigenic analyses of the viruses revealed close relationship (R-values 0.93-0.96). Under the experimental conditions, we have been able to induce IHP using FAV serotype 4 isolate AD: 411 and were also able detect FAV antigens in myocardial tissues by immunofluorescence assay (a new observation), an indication that IHP causing FAV serotype 4 strain replicate in myocardial tissue. Restriction endonuclease analysis of the viral genomes (approximately 46 Kb), using Hind III, Sma I, Xba I, Bam HI, Pst I and Dra I produced identical genetic profiles. Pst I and Bam HI profiles for these six vitus isolates were identical to those published earlier for an IHP causing Pakistani FAV serotype 4 isolate KR31. The identical genetic profiles of viruses, chronology of the outbreaks of IHP in Pakistan during 1989 onward and later in Jammu and Kashmir, India (1994), suggest that FAV serotype 4 isolates involved in outbreaks of IHP in India had probably spread from Pakistan. In order to prevent further spread and economic losses due to IHP in India, based on the antigenic relatedness data in this paper, any one of the six studied FAV serotype 4 isolates can be used as a candidate for mass production of CEH culture based killed vaccine.

Isolates of infectious bursal disease virus from India are of very virulent phenotype

Four Indian field isolates, a classical virulent and an attenuated vaccine strains of Infectious bursal disease virus (IBDV) have been characterized by sequence analysis of part of the VP1 gene (from nucleotide 1538-1979) comprising one of viral RNA dependent RNA polymerase motifs. Sequence alignment of these viruses with reported viruses of other countries revealed Indian IBDV field isolates to be 100% similar to very virulent Japanese (OKYM), European (UK661) and Bangladesh (BD3/99) IBD viruses at amino acid level, whereas they had 0.2-0.9% divergence at nucleotide level. Out of the total 24 nucleotide changes found in the Indian field isolates, as well as reported very virulent viruses, only one resulted in amino acid change S-P at 562 position. The Indian field isolates displayed nucleotide divergence of 10.6-11.6% and amino acid divergence of 2.8-3.5% from the classical virulent and attenuated vaccine strains. The RNA dependent RNA polymerase motif from amino acid 528-541, present in the sequence analyzed, was conserved among all the viruses, irrespective of pathotype and serotype. In the phylogenetic tree, based on nucleotide sequence, Indian field viruses were grouped with reported very virulent viruses in one lineage whereas, classical virulent, attenuated vaccine and serotype 2 strains formed part of the second lineage. But in the phylogenetic tree based on amino acid sequence alignment, the serotype 2 strain OH grouped with Indian field isolates and reported very virulent viruses in one lineage and classical virulent and attenuated vaccine strains formed the second lineage.

Differentiation of infectious bursal disease viruses by restriction enzyme analysis of RT-PCR amplified VP1 gene sequence

In order to differentiate infectious bursal disease virus (IBDV) isolates/strains, a quick method of RT-PCR followed by restriction enzyme analysis of VP1 gene sequence is being reported for the first time. A 480 bp fragment, comprising one of the RNA dependent RNA polymerase motifs of VP1 gene sequence of an Indian classical virus, an attenuated vaccine strain, Georgia and two Indian field isolates, genetically similar to reported very virulent strains of IBDV, was amplified by RT-PCR. Restriction enzyme digestion of PCR products with Taq1 enzyme generated distinct profile for field isolates, different from the classical and attenuated viruses, whereas restriction profile with BstNI restriction enzyme was similar in all the viruses, irrespective of the pathotype. Therefore, the present results suggest that Taq1 digestion can be taken up for the differentiation of field isolates from the classical and vaccine strains. The sequence analysis of VPI gene of reported very virulent IBD viruses from Europe and Japan, using 'MapDraw' programme of Lasergene software, revealed similar restriction enzyme profile as in Indian field isolates.