Exploring the Transcriptomic Data of the Australian Paralysis Tick, Ixodes Holocyclus

Ixodes holocyclus is the paralysis tickcommonly found in Australia. I. holocyclus does notcause paralysis in the primary host – bandicoots, butmarkedly affects secondary hosts such as companionanimals, livestock and humans. Holocyclotoxins are theneurotoxin molecules in I. holocyclus responsible forparalysis symptoms. There is a limited understanding ofholocyclotoxins due to the difficulties in purifying andexpressing these toxins in vitro. Next-generationsequencing technologies were utilised for the first time togenerate transcriptome data from two cDNA samples –salivary glands samples collected from female adult ticksengorged on paralysed companion animals and onbandicoots. Contig-encoded proteins in each librarywere annotated according to their best BLAST matchagainst several databases and functionally assigned intosix protein categories: housekeeping, transposableelements, pathogen-related, hypothetical, secreted andnovel. The “secreted protein” category is comprised often protein families: enzymes, protease inhibitors,antigens, mucins, immunity-related, lipocalins, glycinerich,putative secreted, salivary and toxin-like.Comparisons of contig representation between the twolibraries reveal the differential expression of tickproteins collected from different hosts. This studyprovides a preliminary description of the I. holocyclustick salivary gland transcriptome

Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity : a review

Ticks, triatomines, mosquitoes and sand flies comprise a large number of haematophagous arthropods considered vectors of human infectious diseases. While consuming blood to obtain the nutrients necessary to carry on life functions, these insects can transmit pathogenic microorganisms to the vertebrate host. Among the molecules related to the blood-feeding habit, proteases play an essential role. In this review, we provide a panorama of proteases from arthropod vectors involved in haematophagy, in digestion, in egg development and in immunity. As these molecules act in central biological processes, proteases from haematophagous vectors of infectious diseases may influence vector competence to transmit pathogens to their prey, and thus could be valuable targets for vectorial control