Transcriptome-based analysis of putative allergens of Chorioptes texanus

Background Mites of the genus Chorioptes are non-burrowing and cause mange in a wide range of domestic and wild animals including cattle, horses, sheep, goats, panda, moose, camelids, mydaus and alpacas. Molecular biology and host-parasite interactions of Chorioptes texanus are poorly understood, and only a few C. texanus genes and transcript sequences are available in public databases including the allergen genes. Methods Chorioptes texanus RNA was isolated from mites, and the transcriptome of C. texanus was analyzed using bioinformatics tools. Chorioptes texanus unigenes were compared with the allergen protein sequences from the mite allergen database website to predict the potential allergens. Chorioptes texanus putative allergen unigenes were compared with hydrolase genes by building a C. texanus hydrolase gene library with the best match of the homologous sequences. Three allergen genes were cloned and expressed, their recombinant proteins were purified and their allergenic activities were preliminarily investigated. Results Transcriptome sequencing (RNA-Seq) of C. texanus was analyzed and results demonstrated that 33,138 unigenes were assembled with an average length of 751 bp. A total of 15,130 unigenes were annotated and 5598 unigenes were enriched in 262 KEGG signaling pathways. We obtained 209 putative allergen genes and 34 putative allergen-hydrolase genes. Three recombinant allergen proteins were observed to induce different degrees of allergic reactions on rabbit skin. Conclusions The present transcriptome data provide a useful basis for understanding the host-parasite interaction and molecular biology of the C. texanus mite. The allergenic activities of recombinant Euroglyphus maynei 1-like (Eur m 1-like) protein, Dermatophagoides ptreronyssinus 1-like (Der p 1-like) protein and Dermatophagoides ptreronyssinus 7-like (Der p 7-like) protein were preliminarily investigated by intradermal skin test. Meanwhile, differences in eosinophil counts were observed in different injected sites of the skin. The identification of putative allergen genes and hydrolase genes offers opportunities for the development of new diagnostic, prevention and treatment methods.

JENIS DAN KEPADATAN TUNGAU DEBU RUMAH PADA BEBERAPA HABITAT DI RUMAH PENDERITA PENYAKIT ALERGI

House dust mites are the most found allergens in homes scattered throughout the world that associated with allergic manifestations in the respiratory tract and skin, such as bronchial asthma, allergic rhinitis and atopic dermatitis. The most common house dust mite is from the family Pyroglyphidae, four of which have a close relationship with the incidence of allergy: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Dermatophagoides microceras, and Euroglyphus maynei. This study aims to determine the type and density of house dust mites in several habitats in the homes of people with allergic diseases. This study is a descriptive study using cross-sectional method. Samples were dust in allergic patient’s home in Malalayang I, taken from three habitats, namely bed (mattress and bed linen), bedrooms floor and sofa, as many as 96 samples. Of the 96 samples, there are 60 samples positive of dust mites and 36 negative samples. This study found 157 mites (124 adults and 33 larvae mites). Of the 124 adult mites were identified, there are 122 from order Astigmata with the dominant species is Dermatophagoides pteronyssinus, and two others of the order Prostigmata. In each habitat that is in the bed (mattress and bed linen), bedrooms floor and sofa, Pyroglyphidae is the most prevalent.Keywords: house dust mite, allergiesAbstrak. Tungau debu rumah (TDR) adalah alergen dalam rumah terbanyak yang tersebar di seluruh dunia yang dikaitkan dengan manifestasi alergi pada saluran pernapasan dan kulit, seperti asma bronkial, rinitis alergi dan dermatitis atopik. TDR yang paling sering ditemukan adalah dari famili Pyroglyphidae, empat di antaranya memiliki hubungan yang erat dengan kejadian alergi: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Dermatophagoides microceras, dan Euroglyphus maynei. Penelitian ini bertujuan untuk mengetahui jenis dan kepadatan tungau debu rumah pada beberapa habitat di rumah penderita penyakit alergi. Penelitian ini adalah penelitian deskriptif dengan menggunakan metode cross-sectional. Sampel penelitian adalah debu di rumah penderita alergi di Kelurahan Malalayang I yang diambil dari 3 habitat, yaitu tempat tidur (kasur dan sprei), lantai kamar tidur, dan sofa sebanyak 96 sampel. Dari 96 sampel, 60 sampel positif tungau debu dan 36 sampel negatif. Pada penelitian ini ditemukan 157 tungau (124 tungau dewasa dan 33 larva). Dari 124 tungau dewasa yang terindentifikasi, dari ordo Astigmata sebanyak 122 dengan spesies yang dominan adalah Dermatophagoides pteronyssinus, dan dua lainnya dari ordo Prostigmata. Pada masing-masing habitat yaitu di tempat tidur (kasur dan sprei), lantai kamar tidur dan sofa, famili Pyroglyphidae paling banyak ditemukan.Kata kunci: tungau debu rumah, alergi

Phylogenetic analysis of house dust mites

House dust mites live in house dusts and affect the health of humans. Among the many species, Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei have been found to be commonly associated with Ig-E-mediated allergic diseases. As a result, there is increasing effort to develop methods for the diagnosis and treatment of diseases caused by these species. The purpose of the current study was to explore the evolutionary relationships among house dust mites. After adult D. farinae were separated and isolated for total RNA extract, the cDNA coding for Der f 1 and Der f 2 were cloned and sequenced. Then amino acid sequences for group 1 and 2 allergens of two of the most common house dust mites, D. pteronyssinus, E. maynei, were obtained from databases. Interestingly, homological analysis of amino acid sequences showed that both Der p 1 and Der p 2 from D. pteronyssinus had more similarities to Eur m 1 and Eur m 2, respectively, than they had to Der f 1 and Der f 2 from D. farinae. In the phylogenetic trees, D. pteronyssinus clustered with E. maynei, but not with D. farinae, although D. pteronyssinus and D. farinae belong to the same genus according to morphological taxonomy. It was previously assumed that D. pteronyssinus was more similar to E. maynei than to D. farinae at evolutionary levels.