Thumbnail Image

Kerala Veterinary and Animal Sciences University, Wayanad

Browse

20161
Reset filters
Subject: Biochemistry × Author: LAKSHMI R. × End date: 2023 ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    COMPARISON OF INNATE IMMUNITY RELATED GENES IN VECHUR AND CROSSBRED CATTLE AND THEIR EXPRESSION PROFILE IN CLINICAL AND SUBCLINICAL MASTITIS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2016-12-30) LAKSHMI R.; K.K. Jayavardhanan
    Bovine mastitis is considered as the most economically imposing diseases of dairy cattle. Vechur cattle an indigenous breed of Kerala are generally not susceptible to mastitis. Investigation of innate immune mechanism of this breed might provide an insight into the mechanisms involved in the disease resistance. In light of this premise, the present study was carried out to investigate the expression of TLR2, TLR4, and TLR9 in crossbred and Vechur cattle using RT-qPCR, to better understand the immune resistance mechanisms against mastitis and also characterized the promoter and mRNA sequence of TLR genes in Vechur cattle. RT-qPCR analysis showed a significant up fold increase in the TLR2 gene expression in mastitis caused by S. aureus, whereas expression level of TLR4 mRNA was relatively higher in E. coli caused samples. In both S. aureus and E. coli caused mastitis milk samples, relative expression of all three TLRs was found to be significantly high (P ≤ 0.01) in sub-clinical mastitis than the clinical mastitis. So, during early stage of mammary infection these TLRs are expressed at high level to subside the sub-clinical mastitis without precipitating into clinical mastitis. After the challenging the PBMCs with TLR agonist in vitro, relative expression of mRNA of all three TLR genes was higher in Vechur cattle than the crossbred cattle. Furthermore, the expression of TLR2 mRNA was relatively higher in Vechur breed as compared with other TLRs. These findings suggest that one of the reasons for the development of resistance to mastitis in Vechur cattle is associated with the level of expression of TLRs in response to infection. The sequence of promoter region of TLR2 of Vechur cattle with the Bos taurus sequence showed 98 per cent similarity whereas TLR4 and TLR9 revealed 99 per cent similarity. TLR2 and TLR9 revealed variations for three sequence motifs. Significant variants observed for TATA and CAT boxes and multiple putative binding sites in the promoter region of TLR2 and TLR9 genes in Vechur cattle breed, may potentially link the influence the innate immunity response against mastitis diseases. All three TLR mRNA sequences showed 99 per cent homology with Bos taurus sequence and exposed variations for 17 nucleotide in TLR2, 7 nucleotide in TLR4 and 5 nucleotide in TLR9 mRNA. The ectodomain of Vechur cattle displayed 10 LRRs for TLR2, 13 LRRs for TLR4 and 18 LRRs for TLR9. The variation in the extracellular domain of LRRs, which may promote the recognition of pathogen ligand specificity. The primary structure of protein showed highest per cent of leucine amino acid for all three TLRs and alpha helix is the prominent secondary structure seen in all TLRs followed by beta turn and random coil. Phylogenetic tree for TLR genes showed all Bovidae family falling under the same group, indicated conserved nature of TLR genes. The presence of unique structural features and substantial variation for TLR genes in Vechur cattle, may change the confirmation of TLR proteins, which may influence the binding affinity and interaction with pathogen to boost the innate host disease resistance in Vechur cattle.