Assessment of genetic diversity of the fat-tailed Dumba sheep of India by mitochondrial and microsatellite markers.

India has a centuries-old tradition of sheep production and breeding that accomplish economic, agricultural, and religious roles. In addition to the 44 registered sheep breeds, there is a fat-tailed sheep population referred to as Dumba. This study evaluated genetic variation in Dumba sheep and its differentiation from other Indian sheep breeds using mitochondrial DNA and genomic microsatellite loci. Haplotype and nucleotide diversity based on mitochondrial DNA analysis revealed substantially high maternal genetic diversity in Dumba sheep. Major ovine haplogroups A and B observed in sheep populations across the globe registered their presence in the Dumba sheep. The molecular genetic analysis using microsatellite markers also showed high measures of allele (10.125 ± 0.762) and gene diversity (0.749 ± 0.029). Results correspond to the non-bottleneck population that is near mutation-drift equilibrium despite some deficiency in the number of heterozygotes (FIS = 0.043 ± 0.059). Phylogenetic clustering confirmed Dumba to be a distinct population. Results of this study endow authorities with critical information imperative for sustainable utilization and conservation of Indian fat-tailed sheep, which is considered to be an untapped genetic resource contributing to the food security, livelihood, and economic sustainability of rural households in marginal areas of the country.

Expression and lytic efficacy assessment of the Staphylococcus aureus phage SA4 lysin gene.

Treatment of bovine mastitis caused by Staphylococcus (S.) aureus is becoming very difficult due to the emergence of multidrug-resistant strains. Hence, the search for novel therapeutic alternatives has become of great importance. Consequently, bacteriophages and their endolysins have been identified as potential therapeutic alternatives to antibiotic therapy against S. aureus. In the present study, the gene encoding lysin (LysSA4) in S. aureus phage SA4 was cloned and the nucleotide sequence was determined. Sequence analysis of the recombinant clone revealed a single 802-bp open reading frame encoding a artial protein with a calculated mass of 30 kDa. Results of this analysis also indicated that the LysSA4 sequence shared a high homology with endolysin of the GH15 phage and other reported phages. The LysSA4 gene of the SA4 phage was subsequently expressed in Escherichia coli. Recombinant LysSA4 induced the lysis of host bacteria in a spot inoculation test, indicating that the protein was expressed and functionally active. Furthermore, recombinant lysin was found to have lytic activity, albeit a low level, against mastitogenic Staphylococcus isolates of bovine origin. Data from the current study can be used to develop therapeutic tools for treating diseases caused by drug-resistant S. aureus strains.

In vitro assessment of acyclovir permeation across cell monolayers in the presence of absorption enhancers.

The aim of the investigation was to establish transepithelial permeation of acyclovir across Caco-2 and Madin-Darby canine kidney (MDCK) cell monolayers and attempt to improve its permeation by employing absorption enhancers (dimethyl beta cyclodextrin, chitosan hydrochloride and sodium lauryl sulfate) and combinations thereof. Caco-2 and MDCK cell monolayers have been widely employed in studying drug transport, mechanisms of drug transport, and screening of absorption enhancers and excipients. Transepithelial electrical resistance and permeation of 99mTc-mannitol were employed as control parameters to assess the tight junction and paracellular integrity. Permeation of acyclovir in the presence of absorption enhancers was found to be significantly higher compared with drug permeation in their absence when assessed as apparent permeability coefficients (Papp). Synergistic improvements in Papp values of acyclovir were obtained in case-selected combinations of absorption enhancers; dimethyl beta cyclodextrin-chitosan hydrochloride, chitosan hydrochloride-sodium lauryl sulfate, and dimethyl beta cyclodextrin-sodium lauryl sulfate, were used. Recovery and viability assessment studies of both cell monolayers suggested reestablishment of paracellular integrity and no damage to cell membranes. Significantly improved permeation of acyclovir in the presence of selected combinations of absorption enhancers may be used as a viable approach in overcoming the problem of limited oral bioavailability of acyclovir.