A Deep Insight into the Sialotranscriptome of the Gulf Coast Tick, Amblyomma maculatum

Abstract

BackgroundSaliva of blood sucking arthropods contains compounds that antagonize their hosts' hemostasis, which include platelet aggregation, vasoconstriction and blood clotting; saliva of these organisms also has anti-inflammatory and immunomodullatory properties. Perhaps because hosts mount an active immune response against these compounds, the diversity of these compounds is large even among related blood sucking species. Because of these properties, saliva helps blood feeding as well as help the establishment of pathogens that can be transmitted during blood feeding.Methodology/Principal FindingsWe have obtained 1,626,969 reads by pyrosequencing a salivary gland cDNA library from adult females Amblyomma maculatum ticks at different times of feeding. Assembly of this data produced 72,441 sequences larger than 149 nucleotides from which 15,914 coding sequences were extracted. Of these, 5,353 had >75% coverage to their best match in the non-redundant database from the National Center for Biotechnology information, allowing for the deposition of 4,850 sequences to GenBank. The annotated data sets are available as hyperlinked spreadsheets. Putative secreted proteins were classified in 133 families, most of which have no known function.Conclusions/SignificanceThis data set of proteins constitutes a mining platform for novel pharmacologically active proteins and for uncovering vaccine targets against A. maculatum and the diseases they carry.

Ixodes scapularistick saliva proteins sequentially secreted every 24h during blood feeding

“…To check rabbit proteins, the following databases were used: Oryctolagus cuniculus and refseq-vertebrates databases from NCBI, O. cuniculus from Uniprot, the GeneOntology (GO) FASTA subset [58] the conserved domains database of NCBI [60], containing the COG [61], PFAM [62], and SMART motifs [63]. To functionally classify the protein sequences, a program provided by Dr. José M. C Ribeiro written in Visual Basic 6.0 (Microsoft, Redmond, Washington, USA) was used [34]. The functionally annotated catalog for each dataset was manually curated and input in a hyperlinked Excel spreadsheet (S1 and S2 Tables).…”

“…Of the 130 rabbit proteins that were detected in I. scapularis tick saliva, 83 met the criteria for authentication. When subjected to auto-annotation [34], 582 tick and 83 rabbit high confidence proteins respectively classified into 24 ( Tables 1 and 2 summarizes cumulative numbers of proteins that were identified in each functional class, apparent relative abundance at each time point, and time points at where class were not detected [represented by zero (0)].…”

“…With the advent of next-generation sequencing (NGS) technologies, tick salivary gland transcriptomes have been described [23,[30][31][32][33][34][35][36][37][38][39]. However, the major limitation to these data is that it does not inform on which transcripts that encode for proteins are secreted in tick saliva.…”

Novel Vaccinology Approaches against Ticks

“…The efforts to characterize the genomes of other ticks like Ixodes scapularis and the current studies implying the use of cDNA libraries of R. annulatus [5,6], R. microplus [7], A. variegatum [8], I scapularis [9] in the identification of novel molecules, will impact on the discovery of new tick-protective antigens. The use of the information deduced from the open reading frames in conjugation with functional analysis using technologies such as RNAi, bioinformatics, mutagenesis, transcriptomics, proteomics will allow for rapid discovery of novel tick vaccines.High-throughput studies for some tick species have been accomplished such as the deer tick; I. scapularis, blacklegged tick; Ixodes pacificus, the Rocky mountain wood tick; Dermacentor andersoni, the tropical bont tick; Amblyomma variegatum, the castor bean tick; Ixodes ricinus [10], Rhipicephalus haemaphysaloides [11], the Gulf coast tick; Amblyomma maculatum [12] and the coarse bontlegged tick; Hyalomma marignatum rufipes [13]. The authors have investigated the sialotranscriptome and proteome in tick salivary glands of previously mentioned tick species.…”

“…High-throughput studies for some tick species have been accomplished such as the deer tick; I. scapularis, blacklegged tick; Ixodes pacificus, the Rocky mountain wood tick; Dermacentor andersoni, the tropical bont tick; Amblyomma variegatum, the castor bean tick; Ixodes ricinus [10], Rhipicephalus haemaphysaloides [11], the Gulf coast tick; Amblyomma maculatum [12] and the coarse bontlegged tick; Hyalomma marignatum rufipes [13]. The authors have investigated the sialotranscriptome and proteome in tick salivary glands of previously mentioned tick species.…”