Paritosh Joshi

Isolation of a spermatozoa motility inhibiting factor from chicken seminal plasma with antibacterial property

A 78-kDa spermatozoa motility inhibiting factor (SMIF) was purified from chicken (Gallus domesticus) seminal plasma by anion exchange (DE-53) followed by affinity chromatography on concanavalin A-Sepharose. The factor is thermostable and inhibited the spermatozoa motility in a dose dependent manner. In addition, SMIF inhibited the growth of gram negative bacteria, Pasteurella multocida but not gram positive Streptococcus equi. The factor lost its spermatozoa immobilizing property after treatment with trypsin, chymotrypsin or pepsin. The inhibition of SMIF by beta-mercaptoethanol suggest the involvement of disulfide bonds in its activity. Similarly, this property was lost in presence of chicken seminal plasma or incubating SMIF with anti-SMIF antibodies. Evidence is provided for the presence of a high molecular weight protein (> 100 kDa) in chicken seminal plasma that neutralizes the motility inhibiting property of SMIF. No significant decrease in spermatozoa ATP was observed in presence of SMIF suggesting that the loss of spermatozoa motility was due to factors other than depletion in cells energy. Using anti-SMIF antibodies, a cross-reactive protein was identified in the blood, liver and reproductive tissues of chicken and the seminal plasma of cattle and buffalo. However, the cross-reactive protein failed to inhibit chicken spermatozoa motility. The significance of SMIF in chicken seminal plasma is discussed.

Identification of PDC-109-like protein(s) in buffalo seminal plasma

The FN-2 family of seminal plasma proteins represents the major protein fraction of bovine seminal plasma. These proteins also constitute the major seminal plasma proteins fraction in horse, goat and bison seminal plasma and are present in pig, rat, mouse, hamster and human seminal plasma. BSP-A1 and BSP-A2, the predominant proteins of the FN-2 family, are collectively termed as PDC-109. Fn-2 proteins play an important role in fertilization, including sperm capacitation and formation of oviductal sperm reservoirs. Significantly, BSP proteins were also shown to have negative effects in the context of sperm storage. No conclusive evidence for the presence of buffalo seminal plasma protein(s) similar to PDC-109 exists. Studies with buffalo seminal plasma indicated that isolation and identification of PDC-109-like protein(s) from buffalo seminal plasma by conventional methods might be difficult. Thus, antibodies raised against PDC-109 isolated, and purified from cattle seminal plasma, were used for investigating the presence of PDC-109-like protein(s) in buffalo seminal plasma. Buffalo seminal plasma proteins were resolved on SDS-PAGE, blotted to nitro cellulose membranes and probed for the presence of PDC-109-like protein(s) using the PDC-109 antisera raised in rabbits. A distinct immunoreactive band well below the 20-kDa regions indicated the presence of PDC-109-like protein(s) in buffalo seminal plasma.

Haemonchus contortus calreticulin binds to C-reactive protein of its host, a novel survival strategy of the parasite

Calreticulin (CalR), a Ca2+ binding multifunctional protein, is secreted by the parasitic nematode Haemonchus contortus. We have earlier observed binding of this protein to a 24‐kDa polypeptide (p24) present in an enriched preparation of prothrombin. In the present study, the identity of p24 was established as a C‐reactive protein (CRP) by several criteria. CalR binding to CRP is an elegant strategy devised by the parasite to survive in the host. The secreted CalR may achieve this either by limiting the free concentration of CRP, which has antiparasite activity or inhibit the activation of the classical complement pathway triggered on binding of CRP to C1q protein. CalR binding to CRP would also ensure a check on the procoagulant activity of the CRP enabling parasite to feed on the host blood. Thus, targeting CalR could be a novel strategy to tackle this parasite, which has developed resistance to many anthelmintics.

Molecular characterization and expression profile of uterine serpin (SERPINA14) during different reproductive phases in water buffalo (Bubalus bubalis).

Uterine serpins (SERPINA14) play important roles during pregnancy in the farm animals. In this study, we have cloned and characterized cDNA sequence encoding the bubaline SERPINA14. We also studied its spatio-temporal expression in the uterine endometrium. The bubaline SERPINA14 has an open reading frame of 1299bp. Itshares ∼90% identity with the SERPINA14 of other ruminant livestock species. Phylogenetically, bubaline SERPINA14 has been placed in the same clade that contained other mammalian homologues with a maximum identity to bovine SERPINA14. Using an anti-ovine monoclonal antibody, Western blot analysis of the uterine fluid of buffalo during the early stage of pregnancy confirmed the presence of SERPINA14 of about 48,000Da. The results of quantitative real time PCR (RT-qPCR) as well as in situ hybridization demonstrated a stage and tissue specific expression of bubaline SERPINA14. The level of SERPINA14 mRNA was low during stage I (Days 3-5), which increased (P<0.05) during stage II (Days 6-15) and then subsequently declined during stage III (Days 16-21) of the estrus cycle. During early pregnancy (Days ∼30 of gestation) the level of SERPINA14 mRNA was as high as that during stage II of the estrus cycle. The SERPINA14 mRNA was localized in the glandular epithelium. The differential spatio-temporal expression of SERPINA14 in the uterine endometrium of buffalo suggests its plausible important roles in reproduction.

Sero-surveillance for surra in cattle using native surface glycoprotein antigen from Trypanosoma evansi

Surra, caused by Trypanosoma evansi affects a wide range of domestic and wild animals in the tropics, taking a huge toll on the already impoverished economy here. In bovines surra normally develops into a chronic infection that is often associated with severe production losses, yet with no distinct clinical signs making its adequate diagnosis vital. Though direct microscopic observation of T. evansi in circulation may be the diagnostic gold standard for surra, it is insensitive and impractical for population prevalence studies, making sero-diagnosis the preferred choice for the latter. In this study, we standardize an ELISA with Concanavalin-A (Con-A) affinity purified T. evansi surface glycoprotein antigen and compare its sensitivity and specificity to direct microscopy of stained thin smears and molecular (PCR) diagnostics. The ELISA was then put on field trial for sero-surveillance of cattle for surra in three geographically distinct populations in the Indian subcontinent, to yield an overall sensitivity and specificity of 100% and 89.15% compared to standard stained thin smear examinations and 95.23% and 90.84% compared to blood PCR examinations.

Interferon stimulated gene 15 (ISG15): Molecular characterization and expression profile in endometrium of buffalo (Bubalus bubalis)

Interferon stimulated gene 15 (ISG15), one of the several proteins induced by conceptus derived Type I and/or a Type II interferon (IFN), is implicated as an important factor in determining the uterine receptivity and conceptus development. However, presence as well as specific role of the ISG15 in buffalo (Bubalus bubalis) reproduction is yet to be elucidated. In the present study, both genomic and cDNA sequences of bubaline (bu) ISG15 were cloned and investigated for its expression in different tissues of female reproductive tract of buffalo. Sequence analysis revealed 100% identity among the genomic sequences (1014 bp) of buISG15 from three different breeds of buffalo (viz., Murrah: Acc. No. DQ118137, Mehsana: Acc. No. DQ118138, and Nagpuri: Acc. No. DQ118136) and cDNAs (Acc. Nos. HM543268-HM543270). As in cattle, the buISG15 was comprised of two exons of 57 bp and 520 bp encoding a peptide of 154 amino acids. Moreover, the buISG15 cDNA sequence exhibited 98.3% and 98.5% identity with that of taurine and indicine cattle, respectively. Subsequent reverse transcription PCR analysis revealed expression of the buISG15 in the uterine endometrium, corpus luteum (CL), corpus hemorrhagicum and oviduct. Quantitative Real Time PCR (RTqPCR) analysis also confirmed the constitutive expression of the buISG15 in the uterine endometrium during different stages (i.e. estrus, diestrus and proestrus) of estrous cycle and also during early (∼d 30-40) pregnancy. Western blot analysis of the endometrial extract from both estrous cyclic as well as pregnant buffalo demonstrated the presence of only conjugated ISG15 which was >40 kDa. ISG15 mRNA and immune-reactive proteins were localized in the stromal as well as glandular epithelial cells of the uterine endometrium of estrous cyclic as well as pregnant buffalo. However, there was no significant difference in amount of ISG15 mRNA across the different reproductive phases. To conclude, this study will be helpful for the further understanding of the roles of the ISG15 in pregnancy of buffalo cows.

Molecular characterization and expression profile of ghrelin gene during different reproductive phases in buffalo (Bubalus bubalis)

Ghrelin, a novel motilin-related endogenous ligand for growth hormone secretagouge receptor, is implicated in various biological functions, including regulation of female reproduction. But the presence of ghrelin and its role in reproductive functions in buffalo, a species with poor reproductive efficiency, is not known. In the present study full-length ghrelin cDNA was isolated from bubaline abomasum, which encodes the entire prepropeptide of 116 amino acids. The deduced amino acid sequence of ghrelin of buffalo showed >95% and 31% identity with that of ruminants (cattle, sheep, and goat) and humans, respectively. Analysis of synonymous and nonsynonymous nucleotide substitutions in the coding region of ghrelin indicated that these sequences of different species have been under purifying selection. The 3995-bp amplicon of ghrelin gene consisting of 4 exons and 3 introns was cloned with genomic DNA from buffalo. Further, ghrelin expression was determined by quantitative real-time PCR, in situ hybridization, and immunohistochemistry in bubaline endometrial tissues at different stages of the estrous cycle and early pregnancy. Our results indicated the persistent expression of ghrelin mRNA and protein in the endometrium during stage I (day 3-5), stage II (day 6-15), and stage III (day 16-21) of the estrous cycle and also during early (~day 30-40) pregnancy. Immunohistochemistry and quantitative real-time PCR experiments indicated the relatively higher expression of ghrelin in the endometrium during stage II (day 6-15) of the estrous cycle and early pregnancy than during stage I (day 3-5) and stage III (day 16-21) of the estrous cycle, but no statistically significant difference in ghrelin expression was observed among stages. To conclude, the results of the present study indicate the persistent expression of ghrelin in the uterine endometrium throughout the estrous cycle and in early pregnancy which might be helpful in determining its role in buffalo reproduction.