Rajni Chaudhary

Expression Profiling and Identification of Novel SNPs in CatSper2 Gene and Their Influence on Sperm Motility Parameters in Bovines

ABSTRACT 122 randomly selected Vrindavani cattle were studied to detect polymorphism in four fragments of the CatSper2 gene that were comprised of exon 2, 4, 5, and 6 with flanking regions. Using PCR-SSCP and sequencing analysis, three SNPs (T157C, C273A, and A274C) in the first fragment, one SNP (C30G) in the second fragment, and two SNPs (T86G and T292C) in the fourth fragment were identified. The third fragment did not reveal any polymorphism. The SNPs were used for construction of haplotypes and three haplotypes were found. The least square analysis of variance revealed a significant (P < 0.01) effect of haplotype on all three motility parameters. The haplotype II and III were nonsignificantly different from each other while being significantly (P < 0.01) different from haplotype I. The nonsignificant difference of haplotype II with III can lead to a hypothesis that T>G or C>T SNPs may not play a role in sperm motility. However, when the comparison was made between haplotype I and II, it can be inferred that C>T SNP may have a role in sperm motility, as haplotype II has better motility parameters. Expression profiling of Catper2 gene revealed nonsignificant down regulation of CatSper2 gene in poor motility sperm compared to good motility sperm.

Profiling of sperm gene transcripts in crossbred (Bos taurus x Bos indicus) bulls

Crossbred cattle in some sectors of the world have a significant role in enhancing milk production thereby enhancing the per capita milk availability as a human food source. However, there are certain constraints associated with crossbred animals, such as disease susceptibility, increased reproductive problems, repeat breeding and poor seminal quality. The semen of crossbred bulls has a poor freezing capacity, increased cryo-damage, poor mass cell motility, greater percentages of dead/abnormal sperm and poor initial and post-freeze cell motility. The rejection rate of crossbred bulls for cryostorage of semen has been reported to be as great as 50% as a result of unacceptable semen quality. The identification of superior bulls using molecular technologies is needed which necessitates identification of the genes having a role in sperm function. The present study was, therefore, conducted to gain information on identification and expression of genes having a role in sperm motility in crossbred bulls. The gene transcripts in bulls with sperm of superior and inferior quality were profiled in Vrindavani crossbred cattle by microarray analyses and the results were verified by real time-quantitative PCR. Microarray analyses revealed 19,454 genes which were differentially expressed. At a two-fold cut off, 305 genes were differentially (P<0.01) expressed with 160 genes upregulated and 145 genes down regulated. Some of the upregulated candidate genes were further validated by RT-qPCR. These genes had a four to 16 fold upregulation in sperm with inferior motility as compared to sperm of crossbred bulls with superior motility.

Nucleotide variability of protamine genes influencing bull sperm motility variables

Protamines (PRMs), important proteins of chromatin condensation in spermiogenesis, are promising candidate genes to explore markers of sperm motility. The coding and in-silico predicted promoter regions of these genes were investigated in 102 crossbred and 32 purebred cattle. Also, mRNA quantification was done to explore its possibility as diagnostic tool of infertility. The PCR-SSCP analysis indicated there were two band patterns only in fragment I of the PRM1 and fragment II of the PRM2 gene. The sequence analysis revealed A152G and G179A transitions in the PRM1 gene. Similarly, G35A, A49G and A64G transitions were identified in the PRM2 gene which resulted in altered amino acid sequences from arginine (R) to glutamine (Q), from arginine (R) to glycine (G) and from arginine (R) to glycine (G), respectively. This caused the reduction in molecular weight of PRM2 from 2157.66 to 1931.33 Da due to reduction in the number of basic amino acids. These altered properties of the PRM2 protein led to the reduction in Mass Motility (MM: P < 0.01), Initial Progressive Motility (IPM; P < 0.05) and Post Thaw Motility (PTM; P < 0.05) in crossbred bulls. The least squares analysis of variance indicated there was an effect of PRM2 haplotypes on MM (P = 0.0069), IPM (P = 0.0306) and PTM (P = 0.0500) in crossbred cattle and on PTM (P = 0.0408) in the overall cattle population. Based on the RT-qPCR analysis, however, there was not any significant variation of PRM1 and PRM2 gene expression among sperm of Vrindavani bulls with relatively lesser and greater sperm motility.

Single Nucleotide Polymorphisms in 5’ Upstream Region of Bovine TLR4 Gene Affecting Expression Profile and Transcription Factor Binding Sites

ABSTRACT The present study in the 5’ upstream region of TLR4 gene revealed four Single Nucleotide Polymorphisms (SNPs) in Vrindavani and Tharparkar cattle. The polymorphic information content (PIC), heterozygosity and allelic diversity values were low to moderate for these SNPs. In Vrindavani cattle, one SNP was found to be in Hardy-Weinberg Equilibrium (HWE) and the remaining three were found to be in linkage disequilibrium (LD) as indicated statistically (P > 0.05). In Tharparkar cattle, two SNPs were found to be in HWE and were not in LD as indicated statistically (P > 0.05). These SNPs were used for construction of haplotypes. In-silico analysis of these SNPs predicted abolition of eight transcription factor binding sites and creation of eight new sites. The quantitative real time PCR analysis did not show any significant variation of gene expression among haplotypes. However, gene expression between breed was found to be significant (P < 0.05) which suggested that upstream region of bovine TLR4 gene has a crucial role in its expression. These findings in TLR4 gene offer essential evidence that can be useful in future research exploring its role in immunity. TLR4 can be used as a marker for selection for disease resistance in bovines.

Genetic and Non-Genetic Factors Influencing Fatty Acid Composition of Dairy Milk: A Review

Milk is a natural, complete and balanced food as it is a rich source of fat, protein, vitamins and minerals. On the same time, many surveys revealed that diet plays an important role as a risk factor for chronic diseases in humans. Prospective cohort studies have identified association between dietary fat type (like saturated fatty acid) and cardiovascular diseases. The concentration of milk fatty acids in ‘model’ milk fat for human health should contain 82% mono unsaturated fatty acids (MUFA). Although it may not possible to achieve this ‘model’ fat composition of milk and manipulation of milk composition fat is possible by altering the feed for dairy cows and through genetic interventions. Till date, major emphasis has been given to increase the amount of milk but in todays scenario, more emphasis should be given to increase the quality of milk. The lower level of palmitic acid (C16: 0) in milk is desired in conjunction with an increase in the amount of cis MUFA and cis PUFA. The DGAT-1 gene (K232A allele) leads to an amino acid change i.e., a lysine to alanine substitution and associated with a higher fraction of C16: 0 in milk fat but less C14: 0, unsaturated C18: 0 and conjugated linoleic acid (CLA). Antioxidants, encapsulation or modified atmosphere packaging can be used to delay or avoid the phenomenon of oxidation fortified milk with PUFA. Thus, the desired fatty acid in milk will be a boon to the health conscious people.

Sequence Based Structural Characterization and Genetic Diversity Analysis of Full Length TLR4 CDS in Crossbred and Indigenous Cattle

ABSTRACT The exploration of candidate genes for immune response in cattle may be vital for improving our understanding regarding the species specific response to pathogens. Toll-like receptor 4 (TLR4) is mostly involved in protection against the deleterious effects of Gram negative pathogens. Approximately 2.6 kb long cDNA sequence of TLR4 gene covering the entire coding region was characterized in two Indian milk cattle (Vrindavani and Tharparkar). The phylogenetic analysis confirmed that the bovine TLR4 was apparently evolved from an ancestral form that predated the appearance of vertebrates, and it is grouped with buffalo, yak, and mithun TLR4s. Sequence analysis revealed a 2526-nucleotide long open reading frame (ORF) encoding 841 amino acids, similar to other cattle breeds. The calculated molecular weight of the translated ORF was 96144 and 96040.9 Da; the isoelectric point was 6.35 and 6.42 in Vrindavani and Tharparkar cattle, respectively. The Simple Modular Architecture Research Tool (SMART) analysis identified 14 leucine rich repeats (LRR) motifs in bovine TLR4 protein. The deduced TLR4 amino acid sequence of Tharparkar had 4 different substitutions as compared to Bos taurus, Sahiwal, and Vrindavani. The signal peptide cleavage site predicted to lie between 16th and 17th amino acid of mature peptide. The transmebrane helix was identified between 635–657 amino acids in the mature peptide.

Corrosion Inhibition of Acidic Corrosion of Mild Steel in Acidic Medium by Cetyl Trimethyl Ammonium Chloride

The inhibition effect of Cetyl trimethyl ammonium chloride (CTMAC) on the corrosion of mild steel in 0.5M hydrochloric acid solution was investigated at different temperatures using weight loss measurement, electrochemical polarization and scanning electron microscopy. Weight loss measurement and electrochemical polarization curves revealed that this surfactant inhibits the mild steel corrosion and inhibition efficiencies up to 98% can be obtained. The inhibition efficiency calculated from these techniques is in reasonably good agreement. The observed corrosion data indicate that the inhibition of mild steel corrosion is due to the adsorption of the inhibitor molecules on the mild steel surface. The surface morphology of mild steel samples in absence and presence of the inhibitor was examined using scanning electron microscopy.