Iranian Journal of Parasitology 2016. 11(2):253-258.

5.8S rRNA Sequence and Secondary Structure in Parabronema skrjabini and Related Habronematidae Species


Background: Genomic DNA was isolated from Parabronema skrjabini. rRNA region was amplified and sequenced.

Methods: The RNA secondary structure was predicted using mfold software ( The secondary structure with bulge, hairpins, helices, interior, external and multi loops was predicted for 5.8srDNA of our sequence of P. skrjabini and a sequence of P. skrjabini and two species of Habronema (H. microstoma and H. muscae) in GenBank. RNA motifs were predicted by MEME program version 4.10.2. 

Results: The length of 5.8S rRNA sequence for P. skrjabini#1, P. skrjabini#2, H. microstoma and H. muscae was 158, 156, 127 and 127bp, and the DG required for the formation of the secondary structure was -70.50, -56.40, -41.50 and -41.40 kcal/Mol, respectively. Common structural elements were initially recognized with the help of mfold by screening for thermodynamically optimal and suboptimal secondary structures (default settings, with T = 37 °C). The energy levels of the presumptive secondary structures were then calculated with mfold at the DNA level. Both motifs and the sequence of P. skrjabini#1 were completely different from the other analyzed samples. This difference might be due to the differences in host and geographical area.

Conclusion: This is the first molecular study of P. skrjabini in sheep, which could be further used in the structure modeling across Habronematidae.


Parabronema skrjabini; Secondary structure

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