Dataset Information

The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq.

ABSTRACT: Tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interactions, and transcriptional profiling of salivary glands is a powerful tool to do so. Here, we functionally annotated the sialotranscriptomes of these three Amblyomma species, which allowed comparisons between these and other hematophagous arthropod species.mRNA from the salivary glands of A. triste, A. cajennense and A. parvum ticks fed on different host species were pyrosequenced on a 454-Roche platform to generate four A. triste (nymphs fed on guinea pigs and females fed on dogs) libraries, one A. cajennense (females fed on rabbits) library and one was A. parvum (females fed on dogs) library. Bioinformatic analyses used in-house programs with a customized pipeline employing standard assembly and alignment algorithms, protein databases and protein servers.Each library yielded an average of 100,000 reads, which were assembled to obtain contigs of coding sequences (CDSs). The sialotranscriptome analyses of A. triste, A. cajennense and A. parvum ticks produced 11,240, 4,604 and 3,796 CDSs, respectively. These CDSs were classified into over 100 distinct protein families with a wide range of putative functions involved in physiological and blood feeding processes and were catalogued in annotated, hyperlinked spreadsheets. We highlighted the putative transcripts encoding saliva components with critical roles during parasitism, such as anticoagulants, immunosuppressants and anti-inflammatory molecules. The salivary content underwent changes in the abundance and repertoire of many transcripts, which depended on the tick and host species.The annotated sialotranscriptomes described herein richly expand the biological knowledge of these three Amblyomma species. These comprehensive databases will be useful for the characterization of salivary proteins and can be applied to control ticks and tick-borne diseases.

SUBMITTER: Garcia GR

PROVIDER: S-EPMC4261526 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

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The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq.

Garcia Gustavo Rocha GR Gardinassi Luiz Gustavo LG Ribeiro José Marcos JM Anatriello Elen E Ferreira Beatriz Rossetti BR Moreira Higo Nasser Santanna HN Mafra Cláudio C Martins Maria Marlene MM Szabó Matias Pablo Juan MP de Miranda-Santos Isabel Kinney Ferreira IK Maruyama Sandra Regina SR

Parasites & vectors 20140908

<h4>Background</h4>Tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathog ...[more]

PMID: 25201527

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Project description:Until recently, Amblyomma cajennense (Fabricius, 1787) was considered to represent a single tick species in the New World. Recent studies have split this taxon into six species. While the A. cajennense species complex or A. cajennense (sensu lato) (s.l.) is currently represented by two species in Brazil, A. cajennense (sensu stricto) (s.s.) and Amblyomma sculptum Berlese, 1888, their geographical distribution is poorly known.The distribution of the A. cajennense (s.l.) in Brazil was determined by morphological examination of all lots of A. cajennense (s.l.) in two large tick collections of Brazil, and by collecting new material during three field expeditions in the possible transition areas between the distribution ranges of A. cajennense (s.s.) and A. sculptum. Phylogenetic analysis inferred from the ITS2 rRNA gene was used to validate morphological results. Morphological description of the nymphal stage of A. cajennense (s.s.) is provided based on laboratory-reared specimens.From the tick collections, a total 12,512 adult ticks were examined and identified as 312 A. cajennense (s.s.), 6,252 A. sculptum and 5,948 A. cajennense (s.l.). A total of 1,746 ticks from 77 localities were collected during field expeditions, and were identified as 249 A. cajennense (s.s.), 443 A. sculptum, and 1,054 A. cajennense (s.l.) [these A. cajennense (s.l.) ticks were considered to be males of either A. cajennense (s.s.) or A. sculptum]. At least 23 localities contained the presence of both A. cajennense (s.s.) and A. sculptum in sympatry. DNA sequences of the ITS2 gene of 50 ticks from 30 localities confirmed the results of the morphological analyses. The nymph of A. cajennense (s.s.) is morphologically very similar to A. sculptum.Our results confirmed that A. cajennense (s.l.) is currently represented in Brazil by only two species, A. cajennense (s.s.) and A. sculptum. While these species have distinct distribution areas in the country, they are found in sympatry in some transition areas. The current distribution of A. cajennense (s.l.) has important implications to public health, since in Brazil A. sculptum is the most important vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever.

Project description:BackgroundBrazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest spotted fever of the world. In most of the BSF-endemic areas, capybaras (Hydrochoerus hydrochaeris) are the principal host for the tick Amblyomma cajennense, which is the main vector of BSF.MethodsIn 2012, a BSF case was confirmed in a child that was bitten by ticks in a residential park area inhabited by A. cajennense-infested capybaras in Itú municipality, southeastern Brazil. Host questing A. cajennense adult ticks were collected in the residential park and brought alive to the laboratory, where they were macerated and intraperitoneally inoculated into guinea pigs. A tick-inoculated guinea pig that presented high fever was euthanized and its internal organs were macerated and inoculated into additional guinea pigs (guinea pig passage). Tissue samples from guinea pig passages were also used to inoculate Vero cells through the shell vial technique. Infected cells were used for molecular characterization of the rickettsial isolate through PCR and DNA sequencing of fragments of three rickettsial genes (gltA, ompA, and ompB). Blood serum samples were collected from 172 capybaras that inhabited the residential park. Sera were tested through the immunofluorescence assay using R. rickettsii antigen.ResultsA tick-inoculated guinea pig presented high fever accompanied by scrotal reactions (edema and marked redness). These signs were reproduced by consecutive guinea pig passages. Rickettsia was successfully isolated in Vero cells that were inoculated with brain homogenate derived from a 3rd passage-febrile guinea pig. Molecular characterization of this rickettsial isolate (designated as strain ITU) yielded DNA sequences that were all 100% identical to corresponding sequences of R. rickettsii in Genbank. A total of 83 (48.3%) out of 172 capybaras were seroreactive to R. rickettsii, with endpoint titers ranging from 64 to 8192.ConclusionsA viable isolate of R. rickettsii was obtained from the tick A. cajennense, comprising the first viable R. rickettsi isolate from this tick species during the last 60 years. Nearly half of the capybara population of the residential park was seroreactive to R. rickettsii, corroborating the findings that the local A. cajennense population was infected by R. rickettsii.

Dataset Information

The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq.

Publications

The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq.

Similar Datasets

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