Objective To look for the genes of Schistosoma japonicum related to the Schistosoma-resistance of Microtus fortis.Methods The fresh sera of Microtus fortis were used to screen a T7 phage display cDNA library from worms of Schistosoma japonicum established in our lab.The positive clones were sequenced and functionally analysed through bioinformatics.Results The specific phages binding to the sera of Microtus fortis were enriched 857-fold after three rounds of biopanning,and 58 positive clones picked at random were sequenced and 10 ESTs were obtained.BLASTn results showed that 7 ESTs had 99%-100% similarity to the genes of Shistosoma japonicum reported in GenBank and 1 EST had 82% similarity to a zinc finger protein encoden gene from Pan troglodytes.The results of these ESTs function prediction indicated most of them were involved in the regulation of gene expresion of Schistosoma japonicum.Conclusions Several target genes of Schistosoma japonicum related to the Schistosoma-resistance of Microtus fortis are obtained and those would lay foundation to expatiate the native resistance mechnism of Microtus fortis to Schistosoma japonicum.

Objective To screen protective antigen genes and construct the T7 phage display library from adult worms of Schistosoma japonicum.Methods Total RNA was extracted from adult worms of S.japonicum by Trizol reagent and mRNA was isolated from the total RNA.The ds cDNA was synthesized by reverse transcription using random primer.Directional EcoRⅠ/HindⅢ linkers were ligated into the ends of ds cDNA and the ds cDNA was digested with EcoRⅠand HindⅢ,which resulted in ds cDNA with EcoRⅠand HindⅢ adhering ends.The digested ds cDNA fragments longer than 300 bp in length were fractionated and ligated into T7 Select 10-3b vector.After packaging in vitro,the T7 Select 10-3b vector was transformed into BLT5403 to construct the T7 phage display cDNA library.Plaque assay and PCR were used to evaluate the library.Seven known objective genes of S.japonicum were screened by PCR to detect the representation of the library.Result Primary library capacity was 4.98?106 pfu,and the titer of amplified library was 3.85?1011 pfu/mL.The PCR identification result of 96 clones picked at random showed that recombination rate was 93.8%,in which 95.6% inserted cDNA fragments were longer than 300 bp in length.All the seven known objective genes of S.japonicum were amplified from the library.Conclusion The T7 phage display library from adult worms of Schistosoma japonicum was constructed.

Objective To construct a T7 phage display cDNA library from the lung of Microtus fortis for further screening the schistosomiasis-resistence-related genes of Microtus fortis. Methods mRNA was isolated from total RNA extracted from the lungs of Microtus fortis by TRIzol reagent, and was used to synthesize double strain cDNA by the reverse transcription. Then the double strain cDNA was given with EcoRⅠ and Hind Ⅲ adhering ends by ligation with the directional EcoRⅠ/Hind Ⅲ linkers and digestion with EcoRⅠ and Hind Ⅲ. The double strain cDNA fragments longer than 300 bp in length were fractionated by the Mini Column, and ligated into the T7 Select 10-3b vector with EcoRⅠ and Hind Ⅲ adhering ends. After packaging in vitro, the recombinant T7 Select 10-3b was transformed into BLT5403 to construct a T7 phage display cDNA library. Results The library constructed here contained 1.5?106 clones and the titer of the amplied library was 1.1?1012 pfu/ml. The PCR identification results of 100 clones picked at random showed that 91% clones were recombinant and 90% of recombinant clones contained cDNA fragments longer than 300 bp in length. Conclusion A T7 phage display cDNA library from the lung of Microtus fortis is successfully constructed.

Microtus fortis is naturally resisitent to Schistosoma japonicum. In order to find schistosome-resistence-related genes of Microtus fortis, a T7 phage-display cDNA library from liver of Microtus fortis was screened with the soluble lysate of schistosomula. The specific phages were enriched 375-fold after 3 rounds of biopanning. Ninety-two positive clones picked at random were sequenced and 19 ESTs including 6 unreported genes were obtained. Compared with the negative phage clone control, five positive clones, No.4 (GenBank Accession No.: EW968294), No.13 (GenBank Accession No.: EW968303), No.14 (GenBank Accession No.: EW968304), No.15 (GenBank Accession No.: EW968305) and No.18 (GenBank Accession No.: EW968308) could induce significantly higher schistosomula mortality rate when co-cultivated with schistosomula. According to the function analysis and the shistosomula-killing effect in vitro, the genes encoding CASP8 and FADD-like apoptosis regulator isoform protein, alpha-2-HS-glycoprotein, M4 protein, R3H domain (binds single-stranded nucleic acids) isoform 2 and 3 previously unreported proteins (No.14, No.15 and No.18) obtained here, were schistosomiasis-resistence-related genes of Microtus fortis.
Animals ; Arvicolinae ; genetics ; parasitology ; Bacteriophage T7 ; genetics ; Cloning, Molecular ; Expressed Sequence Tags ; Gene Library ; Genes, Helminth ; genetics ; Immunity, Innate ; genetics ; Larva ; genetics ; growth & development ; Liver ; chemistry ; Schistosoma japonicum ; genetics ; growth & development