ABSTRACT
Background: Dermatophagoides farinae and Dermatophagoides pteronyssinus are house dust mites [HDM] that they cause severe asthma and allergic symptoms. Tropomyosin protein plays an important role in mentioned immune and allergic reactions to HDMs. Here, tropomyosin protein from Dermatophagoides spp. was comprehensively screened in silico for its allergenicity, antigenicity and similarity/conservation.
Materials and Methods: The amino acid sequences of D. farinae tropomyosin, D. pteronyssinus and other mites were retrieved. We included alignments and evaluated conserved/ variable regions along sequences, constructed their phylogenetic tree and estimated overall mean distances. Then, followed by with prediction of linear B-cell epitope based on different approaches, and besides in-silico evaluation of IgE epitopes allergenicity [by SVMc, IgE epitope, ARPs BLAST, MAST and hybrid method]. Finally, comparative analysis of results by different approaches was made.
Results: Alignment results revealed near complete identity between D. farina and D. pteronyssinus members, and also there was close similarity among Dermatophagoides spp. Most of the variations among mites' tropomyosin were approximately located at amino acids 23 to 80, 108 to 120, 142 to 153 and 220 to 230. Topology of tree showed close relationships among mites in tropomyosin protein sequence, although their sequences in D. farina, D. pteronyssinus and Psoroptes ovis are more similar to each other and clustered. Dermanyssus gallinae [AC: Q2WBI0] has less relationship to other mites, being located in a separate branch. Hydrophilicity and flexibility plots revealed that many parts of this protein have potential to be hydrophilic and flexible. Surface accessibility represented 7 different epitopes. Beta-turns in this protein are with high probability in the middle part and its two terminals. Kolaskar and Tongaonkar method analysis represented 11 immunogenic epitopes between amino acids 7-16. From comparative analysis of predicted probable consensus epitope regions by machine learning approaches these epitopes were gained: AA23-48, AA59-80, AA91-110, AA114-143, AA154-168, AA182-200, AA208-225, and AA254-272. Prediction of allergenic proteins by AlgPred server showed 10 matches for IgE epitope, and prediction by hybrid approach showed that IgE epitope is undoubtedly the major allergen.
Conclusion: Immunoinformatic approaches in allergenic protein analysis are now reliable tools for explanation/interpretation of clinically observed complexities. Results of present study, would help in HDM immunotherapy against several species of parasites as a wide range epitopic desensitization or prevention [vaccine] regime.
ABSTRACT
Boophilus genus ticks are responsible for transferring some pathogens and reducing production factors in cattle. Tropomysin [TPM] protein has actin regulator activity and playing important role in immune and allergic reactions. The main goal is to determine different aspects of phylogenetic, similarity, homology, structure and allergenicity of TPM protein. In prior study, we identified TPM by using Mass-spectrometry in Boophilus anulatus larva proteins extraction. Analysis by NCBI and Mascot software showed complete similarity of this protein with Boophilus microplus. TPM Blasting, invertebrates TPM sequences retrieval, aligning and analyzing of conserved and variable regions along sequences were next steps. Also, construction the phylogenetic tree, overall mean distances estimation, homology protein secondary structure, allergencity analysis was achieved. The most similar sequences to Boophilus genus TPM are Haemaphysalis sp., Scolopendra sp. and etc., respectively. The multiple sequence alignment showed that conserved and variable regions stretched in different part of TPM. The close relationships in Phylogenetic tree between Ticks and Mites were seen, although the TPM sequences in ticks are more similar to each other than to mites and assume as the nearest relatives. Insects TPM like worms, located in two separated clades, and Trichinella spiralis in worm clades are more related taxa to members of ticks and mites groups. Furthermore, overall mean distances over sequence pairs reflects TPM conservation during speciation. TPM has high homology in different species and has two domain of ?-helix that cannot form disulfide bonds. Finally, allergenicity analysis by separated and hybrid approach showed it undoubted is allergen and candidates some peptides as responsible for allergenicity of TPM. The comprehensive analysis of TPM has never been easy, especially when we attempt to make statements from different aspects about this protein. Our study revealed the some unique and valuable aspects of TPM protein of Boophilus genus, and will help to further studies on mentioned protein
ABSTRACT
The geographical distribution and ecological preferences of Haemaphysalis in domestic animals in Iran were studied 4 times a year from April 2003 to March 2005. A total of 1,622 ixodid tick specimens were collected from 3 different zones. Among them, 108 (6.7%) Haemaphysalis ticks, consisting of 6 species, were identified; H. punctata (3.4%), H. parva (0.5%), H. sulcata (0.6%), H. choldokovskyi (1.7%), H. concinna (0.06%) and Haemaphysalis sp. (0.6%). H. punctata was the most abundant species, whereas H. concinna was the rarest species collected in humid and sub-humid zones on cattle, sheep and goats. H. choldokovskyi was principally collected from sheep and goats grazed in cold mountainous areas. The infested areas consisted of Caspian Sea (Guilan, Mazandaran, Golestan, and central provinces), mountainous (Azarbaiejan, Ardebil, Kohgilouyeh, and Kordestan) and semi-dessert (Khorasan, Semnan, Kerman, Sistan, and Baluchestan) zones. The Caspian Sea zone (23.6%) was the most highly infested region. The results show that various species of Haemaphysalis ticks infest domestic ruminants in Iran and each tick species show characteristic geographical distributions.