cDNA library construction of two human Demodex species

The research of Demodex , a type of pathogen causing various dermatoses in animals and human beings, is lacking at RNA level. This study aims at extracting RNA and constructing cDNA library for Demodex . First, P. cuniculi and D. farinae were mixed to establish homogenization method for RNA extraction. Second, D. folliculorum and D. brevis were collected and preserved in Trizol, which were mixed with D. farinae respectively to extract RNA. Finally, cDNA library was constructed and its quality was assessed. The results indicated that for D. folliculorum & D. farinae , the recombination rate of cDNA library was 90.67% and the library titer was 7.50 × 10 4 pfu/ml. 17 of the 59 positive clones were predicted to be of D. folliculorum ; For D. brevis & D. farinae , the recombination rate was 90.96% and the library titer was 7.85 × 10 4 pfu/ml. 40 of the 59 positive clones were predicted to be of D. brevis . Further detection by specific primers demonstrated that mtDNA cox1 , cox3 and ATP6 detected from cDNA libraries had 96.52%–99.73% identities with the corresponding sequences in GenBank. In conclusion, the cDNA libraries constructed for Demodex mixed with D. farinae were successful and could satisfy the requirements for functional genes detection.