Bhaskar Sharma

The nucleotide sequence and deduced amino acid composition of the haemagglutinin and fusion proteins of the morbillivirus phocid distemper virus

The amino acid composition of the two surface proteins of the recently isolated morbillivirus phocid distemper virus (PDV) were deduced from the nucleotide sequence. The fusion (F) protein of PDV exhibited characteristics similar to those of other morbillivirus F proteins. The overall amino acid similarity with its closest homologue, canine distemper virus (CDV), was 72%. From the context of the starting codons and the requirement for a hydrophobic signal peptide, it is likely that translation of the PDV F mRNA starts at the third AUG, corresponding to codon 95 in the long open reading frame of the PDV F gene. After removal of the signal peptide, F0 starts at amino acid 105. From this position the F protein of PDV and CDV exhibit 84% amino acid similarity. The PDV haemagglutinin (H) protein showed 74% amino acid similarity with CDV H protein and highly conserved features responsible for the tertiary structure. Despite these similarities, the two H proteins show marked antigenic differences when probed with monoclonal antibodies. Earlier studies have indicated that rinderpest virus (RPV) is the prototype virus of the morbillivirus genus, from which first CDV/PDV and later measles virus (MV) evolved. From the close relationship shown in this study, it is likely that the divergence of CDV and PDV occurred after MV evolved from RPV.

Changes in oxidative stress indices, zinc and copper concentrations in blood in canine demodicosis.

Status of certain oxidative stress indices and zinc and copper concentrations in blood were estimated in dogs with localized demodicosis (LD) and generalized demodicosis (GD). In comparison to healthy control, erythrocytic lipid peroxides level and superoxide dismutase activity were significantly (P<0.01) higher in both LD as well as GD. However, level of reduced glutathione and activity of catalase were significantly (P<0.01) lower in both LD and GD. Blood zinc and copper levels in dogs with LD and GD were significantly (P<0.01) lower than healthy control. Significant (P<0.01) differences were also observed in different oxidative stress indices and zinc and copper levels in between LD and GD groups. From the present study, it was concluded that demodicosis is associated with oxidative stress and antioxidant supplementation may be beneficial in management of canine demodicosis.

Induction of apoptosis in Vero cells by Newcastle disease virus requires viral replication, de-novo protein synthesis and caspase activation

Newcastle disease virus causes (NDV) apoptotic death of infected cells. In the present study, the stimulus that provoked the induction of apoptosis in infected cells was examined. Vero cells infected with NDV developed apoptosis as characterized by DNA fragmentation and decreased DNA content. In presence of ammonium chloride, infected cells did not show reduced DNA content indicating the requirement of virus entry for the induction of apoptosis. UV-inactivated NDV did not induce apoptosis in cells suggesting the need of virus replication. Although cycloheximide blocked NDV-induced apoptosis, actinomycin-D did not, suggesting that de-novo viral protein synthesis was critical for the induction of apoptosis. In addition, activation of caspases was also detected by flowcytometry, indirect fluorescent and colorimetric assays. Based on the results, it was concluded that NDV-induced apoptosis in Vero cells required virus replication, de-novo protein synthesis and caspase activation.

Isolation, culture and characterization of caprine mesenchymal stem cells derived from amniotic fluid

Amniotic fluid (AF) represents heterologous cell types and a specific group of these cells show high growth rate and multipotent characteristics. The aim of the present study was to culture and fully characterize the putative stem cell population isolated from caprine mesenchymal stem cells. Plastic adherent fibroblastoid cell population could be successfully isolated from the caprine amniotic fluid. In vitro expanded caprine amniotic fluid derived mesenchymal stem cells (cAF-MSCs) showed high proliferation ratio with a doubling time of 33.1h and stained positive for alkaline phosphatase. Relative transcript abundance of CD-73, CD-90 and CD-105 surface markers were analyzed by SYBR green based real time PCR and their respective proteins were localized through immunocytochemistry, however cAF-MSCs were found negative for haematopoietic marker CD-34. When exposed to corresponding induction condition, cAF-MSCs differentiated into osteogenic, adipogenic and chondrogenic lineages which was confirmed through von Kossa, Oil Red O and Alcian blue staining respectively. Furthermore, these cells were found positive for undifferentiated embryonic stem cell markers like Oct-4, Nanog, Sox-2, SSEA-1 and SSEA-4 which accentuate their pluripotent property. In conclusion, caprine amniotic fluid represents a promising source of mesenchymal stem cells with high proliferative and differentiation potential and these cells offer their scope for multiple regenerative therapies.

HN protein of Newcastle disease virus causes apoptosis in chicken embryo fibroblast cells

Newcastle disease virus (NDV), an avian paramyxovirus, induces apoptosis in chicken embryo fibroblast (CEF) cells. In the present investigation, the ability of haemagglutinin-neuraminidase (HN) protein of NDV to cause apoptosis in CEF cells was examined. The results revealed that cells expressing the HN protein demonstrated decreased DNA content, phosphatidylserine exposure and increased cytoplasmic vacuolation. Up-regulation of caspase-1, -9, -8, -3, loss of mitochondrial transmembrane potential and an increase in oxidative stress were also observed in cells expressing the HN protein. Based on the above results it can be concluded that HN protein of NDV causes apoptosis in CEF cells.

Time course of Newcastle disease virus-induced apoptotic pathways.

Newcastle disease virus (NDV) causes economically significant Newcastle disease (ND) in almost all birds worldwide. Previous studies have shown that NDV induces caspase dependent apoptotic pathways in infected cells. In the present study, time course induction of apoptotic pathways in Vero cells is described. In NDV-infected cells, caspase-8 activity, percentage of cells showing TRAIL expression was higher at 24h p.i. (post-infection) compared to 48 h p.i. In contrast, caspase-9 activity, efflux of cytochrome c, loss of mitochondrial membrane potential was higher at 48 h compared to 24h p.i. The caspase-3 activity was high both times. Based on these results, it was concluded that at 24h p.i., NDV induces apoptosis through extrinsic apoptotic pathway while at 48 h p.i. predominantly through intrinsic apoptotic pathway.

55 kb Plasmid and Virulence-Associated Genes are Positively Correlated with Salmonella enteritidis Pathogenicity in Mice and Chickens

Twenty-four strains of Salmonella enteritidis, isolated from several outbreaks of salmonellosis from different poultry farms in India, were checked for the plasmid profile and detection of virulence gene(s) by PCR. Most of the strains contained only a single plasmid of 55 kb. Additional plasmids of 23.2 kb and 8.7 kb were seen in one of the strains, and another strain carried only two plasmids of 23.2 kb and 8.7 kb. Four strains did not carry any plasmid. PCR amplification showed the presence of virulence-associated genes in all the isolates harbouring the 55 kb plasmid. Intraperitoneal inoculation of mice, with most of the strains carrying the 55 kb plasmid, caused 100% mortality. Most strains lacking the 55 kb plasmid were avirulent. In chickens, oral inoculation of the S. enteritidis strains carrying the 55 kb plasmid produced 40–100% mortality, with characteristic signs of salmonellosis. Oral inoculation of strains lacking the 55 kb plasmid did not cause any mortality. Hence, it appears that the large plasmid of S. enteritidis probably contributes towards virulence in mice and chickens.

Determination of oxidative status and apoptosis in peripheral blood of dogs with sarcoptic mange.

The aim of the present study was to determine the erythrocytic oxidant/antioxidant balance and apoptosis of peripheral blood leukocytes of dogs with natural Sarcoptes scabiei var. canis mite infestation. A total of twenty four clinically Sarcoptes-infested dogs were examined and used to execute the study. While another twenty four healthy dogs free of any ecto-parasite were used as controls. Peripheral blood samples were obtained from each infested only once on the day of dermatological examinations. Determination of oxidant/antioxidant balance was conceded by estimating the levels of lipid peroxides and antioxidants in erythrocytes. While, apoptosis of peripheral blood leukocytes was determined by estimating externalization of phosphatidylserine (PS) at the cell surface as well as by detection of depolarization mitochondrial membrane potential (ΔΨm) by flow cytometry. Sarcoptes-infested dogs had revealed significantly higher (P≤0.001) contents of erythrocytic lipid peroxides in comparison with the healthy controls. Whereas the level of reduced glutathione was found to be significantly lower (P≤0.001) in Sarcoptes-infested dogs as compared to the healthy dogs. The activity of glutathione peroxidase was found to be significantly lower (P≤0.001) in Sarcoptes-infested dogs as compared to the healthy dogs. The activity of glutathione-S-transferase was also found to be significantly lower (P≤0.001) in Sarcoptes-infested dogs as compared to the healthy dogs. The dogs with sarcoptic mange had revealed significantly lower (P≤0.001) activity of superoxide dismutase in coparision with the healthy dogs. The dogs with sarcoptic mange had also revealed significantly lower (P≤0.001) activity of catalase in coparision with the healthy dogs. The percentage of apoptotic leukocytes was found to be significantly higher (P≤0.001) in Sarcoptes-infested dogs as compared to the healthy controls. Sarcoptes-infested dogs had also exhibited significantly (P≤0.001) higher percentage of leukocytes with depolarized mitochondrial membrane potential in comparison with the healthy controls. It is concluded that significant alteration in oxidant/antioxidant balance and increased rate of apoptosis in peripheral leukocytes may be implicated in the pathogenesis of clinical Sarcoptes mite infestation in dogs.

Molecular characterization of coding sequences and analysis of Toll-like receptor 3 mRNA expression in water buffalo (Bubalus bubalis) and nilgai (Boselaphus tragocamelus)

Toll-like receptor 3 (TLR3), an antiviral innate immunity receptor recognizes double-stranded RNA, preferably of viral origin and induces type I interferon production, which causes maturation of phagocytes and subsequent release of chemical mediators from phagocytes against some viral infections. The present study has characterized TLR3 complementary DNA (cDNA) in buffalo (Bubalus bubalis) and nilgai (Boselaphus tragocamelus). TLR3 coding sequences of both buffalo and nilgai were amplified from cultured dendritic cell cDNA and cloned in pGEMT-easy vector for characterization by restriction endonucleases and nucleotide sequencing. Sequence analysis reveals that 2,715-bp-long TLR3 open reading frame encoding 904 amino acids in buffalo as well as nilgai is similar to that of cattle. Buffalo TLR3 has 98.6 and 97.9% identity at nucleotide level with nilgai and cattle, respectively. Likewise, buffalo TLR3 amino acids share 96.7% identity with cattle and 97.8% with nilgai. Non-synonymous substitutions exceeding synonymous substitutions indicate evolution of this receptor through positive selection among these three ruminant species. Buffalo and nilgai appear to have diverged from a common ancestor in phylogenetic analysis. Predicted protein structures of buffalo and nilgai TLR3 from deduced amino acid sequences indicate that the buffalo and nilgai TLR3 ectodomain may be more efficient in ligand binding than that of cattle. Furthermore, TLR3 messenger RNA expression in tissues as quantified by real-time PCR was found higher in nilgai than buffalo.

Molecular and cellular characterization of buffalo bone marrow-derived mesenchymal stem cells.

Immune privileged mesenchymal stem cells (MSCs) can differentiate into multiple cell types and possess great potential for human and veterinary regenerative therapies. This study was designed with an objective to isolate, expand and characterize buffalo bone marrow-derived MSCs (BM-MSCs) at molecular and cellular level. Buffalo BM-MSCs were isolated by Ficoll density gradient method and cultured in Dulbeccos modified Eagles medium supplemented with fetal bovine serum (FBS). These cells were characterized through alkaline phosphatase (AP) staining, colony-forming unit (CFU) assay, mRNA expression analysis (CD 73, CD 90, CD 105, Oct4 and Nanog), immunolocalization along with flow cytometry (Stro 1, CD 73, CD 105, Oct4, Sox2 and Nanog) and in situ hybridization (Oct4 and Sox2). Multilineage differentiation (osteogenic, adipogenic and chondrogenic) was induced in vitro, which was further assessed by specific staining. Buffalo BM-MSCs have the capacity to form plastic adherent clusters of fibroblast-like cells and were successfully maintained up to 16(th) passage. These cells were AP positive, and further CFU assay confirmed their clonogenic property. RT-PCR analysis and protein localization study showed that buffalo BM-MSCs are positive for various cell surface markers and pluripotency markers. Cytoplasmic distribution of mRNA for pluripotency markers in buffalo BM-MSCs and multilineage differentiation were induced in vitro, which was further assessed by specific staining. To the best of our knowledge, this is the first report of buffalo BM-MSCs, which suggests that MSCs can be derived and expanded from buffalo bone marrow and can be used after characterization as a novel agent for regenerative therapy.