The gene encoding the excretory-secretory antigen of TES-120 from larvae of Toxocara canis was cloned and the sequence was analyzed for utilization as a diagnostic molecule. The total RNA was isolated from T. canis infective larvae and reverse transcription was done with oligo dT primers to obtain complementary DNA (cDNA). Amplification by PCR was performed with cDNA as a template and specific primers of the gene of TES-120, yielding an amplicon size of 530 bp. The amplicon was cloned into pRSETa expression vector. The recombinant clones were transformed into BL21 (DE3) pLysS E. coli expression host and the clone was confirmed by colony PCR, restriction enzyme analysis and sequencing. The nucleotide sequencing of TES-120 gene of TN isolate showed 99.8 % homology with the previously published sequences of UK (U39815.1) and Venezuela isolate (KU951901.1) and 97.0 % homology with the published sequences of Iraq isolate (LC328969.1). Phylogenetic tree revealed close relationship of TN isolate with Venezuela isolate, which had a common ancestor with the UK isolate and it is distantly related to Malaysia isolate of T. cati (KP71707).

The mRNA from distal ileum of Indian goat was cloned and characterized after purification. cDNA was synthesized using goat ileal epithelial RNA, omniscript and sensiscript reverse transcriptase and amplified by Hotstart Taq DNA polymerase with primers designed by taking conserved regions of cattle enteric _Ò-defensin, cattle lingual antimicrobial peptide(LAP) and goat _Ò-defensin-2 sequences. The amplified cDNA of 253bp was, ligated to linearised TA cloning vector and transformed into XLblue strain of E.coli which was grown overnight at 37oC in a LB plate containing ampicillin, IPTG and X-Gal. The recombinant plasmid was isolated and digested with NcoI. The white colonies showed a release of 253bp insert. The sequence analysis showed 26, 16 and 5-nucleotide substitution having 85.6%, 91.3%, 97.4% homology with reported cattle EBD, buffalo EBD and goat BD2 mRNA respectively. The deduced amino acid sequence encodes for a 64 amino acid precursor peptide showing 12,18 and 4 amino acid substitution having 80%, 70.8%, 93.8% homology with buffalo EBD, cattle EBD and goat BD2 peptide respectively. Both nucleotide and amino acid sequence homology showed that the cloned sequence was closer to goat BD2.