Dataset Information

Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed Amblyomma sculptum Ticks and Descriptive Proteome of the Saliva.

ABSTRACT: Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize the tick gut and later the salivary glands (SG) in order to be transmitted during a subsequent blood feeding via saliva. Tick saliva contains a complex mixture of bioactive molecules with anticlotting, antiplatelet aggregation, vasodilatory, anti-inflammatory, and immunomodulatory properties to counteract both the hemostasis and defense mechanisms of the host. Besides facilitating tick feeding, the properties of saliva may also benefits survival and establishment of pathogens in the host. In the current study, we compared the sialotranscriptome of unfed A. sculptum ticks and those fed for 72 h on rabbits using next generation RNA sequencing (RNA-seq). The total of reads obtained were assembled in 9,560 coding sequences (CDSs) distributed in different functional classes. CDSs encoding secreted proteins, including lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, 8.9 kDa superfamily members, and immunity-related proteins were mostly upregulated by blood feeding. Selected CDSs were analyzed by real-time quantitative polymerase chain reaction preceded by reverse transcription (RT-qPCR), corroborating the transcriptional profile obtained by RNA-seq. Finally, high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis revealed 124 proteins in saliva of ticks fed for 96-120 h. The corresponding CDSs of 59 of these proteins were upregulated in SG of fed ticks. To the best of our knowledge, this is the first report on the proteome of A. sculptum saliva. The functional characterization of the identified proteins might reveal potential targets to develop vaccines for tick control and/or blocking of R. rickettsii transmission as well as pharmacological bioproducts with antihemostatic, anti-inflammatory and antibacterial activities.

SUBMITTER: Esteves E

PROVIDER: S-EPMC5702332 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed Amblyomma sculptum Ticks and Descriptive Proteome of the Saliva.

Esteves Eliane E Maruyama Sandra R SR Kawahara Rebeca R Fujita André A Martins Larissa A LA Righi Adne A AA Costa Francisco B FB Palmisano Giuseppe G Labruna Marcelo B MB Sá-Nunes Anderson A Ribeiro José M C JMC Fogaça Andréa C AC

Frontiers in cellular and infection microbiology 20171121

Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize ...[more]

PMID: 29209593

Similar Datasets

Project description:Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize the tick gut and later the salivary glands in order to be transmitted during a subsequent blood feeding via saliva. Tick saliva contains a complex mixture of bioactive molecules with anticlotting, antiplatelet aggregation, vasodilatory, anti-inflammatory, and immunomodulatory properties to counteract both the hemostasis and defense mechanisms of the host. Besides facilitating tick feeding, the properties of saliva may also benefits survival and establishment of pathogens in the host. In the current study, we compared the sialotranscriptome of unfed A. sculptum ticks and those fed for 72 h on rabbits using next generation RNA sequencing (RNA-seq). The total of reads obtained were assembled in 9,560 coding sequences (CDSs) distributed in different functional classes. CDSs encoding secreted proteins, including lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, 8.9 kDa superfamily members, and immunity-related proteins were mostly upregulated by blood feeding. Selected CDSs were analyzed by real-time quantitative polymerase chain reaction preceded by reverse transcription (RT-qPCR), corroborating the transcriptional profile obtained by RNA-seq. Finally, high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis revealed 124 proteins in saliva of ticks fed for 96-120 h. The corresponding CDSs of 59 of these proteins were upregulated in salivary glands of fed ticks. To the best of our knowledge, this is the first report on the proteome of A. sculptum saliva. The functional characterization of the identified proteins might reveal potential targets to develop vaccines for tick control and/or blocking of R. rickettsii transmission as well as pharmacological bioproducts with antihemostatic, anti-inflammatory and antibacterial activities.

Project description:Amblyomma sculptum is a tick affecting animal and human health across Argentina, Bolivia, Paraguay and Brazil. Donkeys, Equus asinus, are known to be resistant to A. sculptum, suggesting that they can produce non-host tick semiochemicals (allomones), as already demonstrated for some other vertebrate host/pest interactions, whereas horses, Equus caballus, are considered as susceptible hosts. In this study, we tested the hypothesis that donkeys produce natural repellents against A. sculptum, by collecting sebum from donkeys and horses, collecting the odour from sebum extracts, and identifying donkey-specific volatile compounds by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS). From the complex collected blends, five main compounds were identified in both species. Hexanal, heptanal and (E)-2-decenal were found predominantly in donkey extracts, whilst ethyl octanoate and ethyl decanoate were found predominantly in horse extracts. One compound, (E)-2-octenal, was detected exclusively in donkey extracts. In Y-tube olfactometer bioassays 36 different A. sculptum nymphs were tested for each extract, compound and concentration. The dry sebum extracts and the compounds identified in both species induced neither attraction nor repellency. Only (E)-2-octenal, the donkey-specific compound, displayed repellency, with more nymphs preferring the arm containing the solvent control when the compound was presented in the test arm across four concentrations tested (p < 0.05, Chi-square test). A combination of a tick attractant (ammonia) and (E)-2-octenal at 0.25 M also resulted in preference for the control arm (p < 0.05, Chi-square test). The use of semiochemicals (allomones) identified from less-preferred hosts in tick management has been successful for repelling brown dog ticks, Rhipicephalus sanguineus sensu lato from dog hosts. These results indicate that (E)-2-octenal could be used similarly to interfere in tick host location and be developed for use in reducing A. sculptum numbers on animal and human hosts.

Project description:BackgroundAmblyomma sculptum is a hard tick that is associated with domestic animals and the transmission of Brazilian spotted fever. This association has motivated several field studies on this ixodid tick within its distribution area in South America. Thorough knowledge of the seasonal dynamics of A. sculptum in different ecological scenarios is required in order to better understand the biological characteristics of this tick and develop techniques for the control and prevention of diseases transmitted by this vector. In this article, we systematically review the seasonal dynamics of A. sculptum and tick collection methodology.MethodsA systematic search of the Scopus, Web of Science, PubMed and Scielo databases was carried out for articles (including dissertations and theses) on the population dynamics of A. sculptum. The inclusion criterion was the report of seasonal dynamic studies on A. sculptum through surveys carried out for at least 1 year with, as methodology, tick collection in the environment and/or tick count/collection on A. sculptum primary hosts (horses or capybaras). Studies carried out before the reclassification of Amblyomma cajennense sensu lato in 2014, which referred to Amblyomma cajennense in areas where it is currently known that only A. sculptum occurs, were also included. Articles meeting the inclusion criterion, but not available in online databases, were also added based on the authors' experience on the subject. Sixteen articles and one thesis were selected for inclusion in this systematic review.ResultsMost of the studies were carried out in the southeastern region of Brazil, with a few also carried out in the northeast, center-west and south of Brazil and northwest of Argentina. Five techniques/methods were applied across these studies: CO2 traps, dragging, flagging, visual searches and tick counting on animals, used alone or in combination.ConclusionSeasonal dynamics of A. sculptum was found to be similar in almost all of the areas studied, with larvae predominating during the autumn, nymphs in the winter and adults in the spring and summer.

Project description:Multiple tick saliva proteins, the majority of which are unknown, confer tick resistance in repeatedly infested animals. The objective of this study was to identify the 24-48 h fed Amblyomma americanum tick saliva immuno-proteome. The 24-48 h tick-feeding phase is critical to tick parasitism as it precedes important events in tick biology, blood meal feeding and disease agent transmission. Fed male, 24 and 96 h fed female phage display cDNA expression libraries were biopanned using rabbit antibodies to 24 and 48 h fed A. americanum female tick saliva proteins. Biopanned immuno-cDNA libraries were subjected to next generation sequencing, de novo assembly, and bioinformatic analysis.More than 800 transcripts that code for 24-48 h fed A. americanum immuno-proteins are described. Of the 895 immuno-proteins, 52% (464/895) were provisionally identified based on matches in GenBank. Of these, ~19% (86/464) show high level of identity to other tick hypothetical proteins, and the rest include putative proteases (serine, cysteine, leukotriene A-4 hydrolase, carboxypeptidases, and metalloproteases), protease inhibitors (serine and cysteine protease inhibitors, tick carboxypeptidase inhibitor), and transporters and/or ligand binding proteins (histamine binding/lipocalin, fatty acid binding, calreticulin, hemelipoprotein, IgG binding protein, ferritin, insulin-like growth factor binding proteins, and evasin). Others include enzymes (glutathione transferase, cytochrome oxidase, protein disulfide isomerase), ribosomal proteins, and those of miscellaneous functions (histamine release factor, selenoproteins, tetraspanin, defensin, heat shock proteins).Data here demonstrate that A. americanum secretes a complex cocktail of immunogenic tick saliva proteins during the first 24-48 h of feeding. Of significance, previously validated immunogenic tick saliva proteins including AV422 protein, calreticulin, histamine release factor, histamine binding/lipocalins, selenoproteins, and paramyosin were identified in this screen, supporting the specificity of the approach in this study. While descriptive, this study opens opportunities for in-depth tick feeding physiology studies.

Dataset Information

Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed Amblyomma sculptum Ticks and Descriptive Proteome of the Saliva.

Publications

Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed <i>Amblyomma sculptum</i> Ticks and Descriptive Proteome of the Saliva.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets