An insight into the sialotranscriptome of the brown dog tick, Rhipicephalus sanguineus

Abstract

BackgroundRhipicephalus sanguineus, known as the brown dog tick, is a common ectoparasite of domestic dogs and can be found worldwide. R.sanguineus is recognized as the primary vector of the etiological agent of canine monocytic ehrlichiosis and canine babesiosis. Here we present the first description of a R. sanguineus salivary gland transcriptome by the production and analysis of 2,034 expressed sequence tags (EST) from two cDNA libraries, one consctructed using mRNA from dissected salivary glands from female ticks fed for 3-5 days (early to mid library, RsSGL1) and the another from ticks fed for 5 days (mid library, RsSGL2), identifying 1,024 clusters of related sequences.ResultsBased on sequence similarities to nine different databases, we identified transcripts of genes that were further categorized according to function. The category of putative housekeeping genes contained ~56% of the sequences and had on average 2.49 ESTs per cluster, the secreted protein category contained 26.6% of the ESTs and had 2.47 EST's/clusters, while 15.3% of the ESTs, mostly singletons, were not classifiable, and were annotated as "unknown function". The secreted category included genes that coded for lipocalins, proteases inhibitors, disintegrins, metalloproteases, immunomodulatory and antiinflammatory proteins, as Evasins and Da-p36, as well as basic-tail and 18.3 kDa proteins, cement proteins, mucins, defensins and antimicrobial peptides. Comparison of the abundance of ESTs from similar contigs of the two salivary gland cDNA libraries allowed the identification of differentially expressed genes, such as genes coding for Evasins and a thrombin inhibitor, which were over expressed in the RsSGL1 (early to mid library) versus RsSGL2 (mid library), indicating their role in inhibition of inflammation at the tick feeding site from the very beginning of the blood meal. Conversely, sequences related to cement (64P), which function has been correlated with tick attachment, was largely expressed in the mid library.ConclusionsOur survey provided an insight into the R. sanguineus sialotranscriptome, which can assist the discovery of new targets for anti-tick vaccines, as well as help to identify pharmacologically active proteins.

Gene expression profiling of adult female tissues in feeding Rhipicephalus microplus cattle ticks

“…Similar to other studies in salivary glands, we identified putative glycine-rich (GGY) cuticlerelated (CV437645) and cement (Contig 2328) proteins that may be involved in structural interactions of the peritrophic matrix between the cuticle and salivary gland tissues, in addition to cement cone 13 formation during attachment (Francischetti et al, 2010;Maruyama et al, 2010), as well as putative mucins (CV452616 and CV444691) (Francischetti et al, 2010). A vaccination trial using a mucin isolated from female R. microplus homogenates could not demonstrate greater protection against infestation compared with that of Bm86 (McKenna et al, 1998).…”

“…Other protease inhibitors related to the thyroglobulin type-1 repeat containing proteins or thyropins (Contig 300) and the alpha-2-macroglobulin family (Contig 2131 and Contig 1745) were identified. Thyropins have been proposed to act as inhibitors of cysteine proteases, as well as binding partners for heparin (Anatriello et al, 2010;Francischetti et al, 2010). Alpha-2-macroglobulins are universal protease inhibitors involved in clearance of exogenous proteases and innate immunity.…”

AeMOPE-1: um novo peptídeo imunomodulador salivar de <i>Aedes aegypti </i>com potencial terapêutico na colite experimental.

“…(3) A molécula AFXa se liga ao fator X ativo e a molécula AaTI se liga à trombina impedindo a coagulação sanguínea. (ANATRIELLO et al, 2010;GARCIA et al, 2014;RIBEIRO et al, 2011;VALENZUELA et al, 2002a). aegypti, a literatura a respeito deste assunto ainda é escassa e pouco se sabe sobre as moléculas responsáveis por tais atividades.…”

Bases moleculares da resistência a ivermectina em Rhipicephalus (Boophilus) microplus

“…A fixação ocorre por meio das peças bucais aproximadamente uma hora após alcançar o hospedeiro. As glândulas salivares começam a secretar um material acelular viscoso que envolve as peças bucais formando um cone de cimento que fixa o carrapato na pele do hospedeiro (de Campos Pereira et al, 2008, Anatriello et al, 2010.…”

“…Dentre as secreções salivares das larvas encontram-se substâncias farmacologicamente ativas com propriedades imunossupresoras, anti-inflamatórias, vasodilatadoras e anti-hemostáticas que permitem evadir o sistema imune do bovino e impedir a coagulação sanguínea favorecendo a alimentação do carrapato (Valenzuela, 2004, de Campos Pereira et al, 2008, Anatriello et al, 2010.…”