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Gerhart JG, Auguste Dutcher H, Brenner AE, Moses AS, Grubhoffer L, Raghavan R. Multiple Acquisitions of Pathogen-Derived Francisella Endosymbionts in Soft Ticks. Genome Biol Evol 2018; 10:607-615. [PMID: 29385445 PMCID: PMC5804916 DOI: 10.1093/gbe/evy021] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2018] [Indexed: 01/14/2023] Open
Abstract
Bacterial endosymbionts of ticks are of interest due to their close evolutionary relationships with tick-vectored pathogens. For instance, whereas many ticks contain Francisella-like endosymbionts (FLEs), others transmit the mammalian pathogen Francisella tularensis. We recently sequenced the genome of an FLE present in the hard tick Amblyomma maculatum (FLE-Am) and showed that it likely evolved from a pathogenic ancestor. In order to expand our understanding of FLEs, in the current study we sequenced the genome of an FLE in the soft tick Ornithodoros moubata and compared it to the genomes of FLE-Am, Francisella persica-an FLE in the soft tick Argus (Persicargas) arboreus, Francisella sp. MA067296-a clinical isolate responsible for an opportunistic human infection, and F. tularensis, the established human pathogen. We determined that FLEs and MA067296 belonged to a sister taxon of mammalian pathogens, and contained inactivated versions of virulence genes present in F. tularensis, indicating that the most recent common ancestor shared by FLEs and F. tularensis was a potential mammalian pathogen. Our analyses also revealed that the two soft ticks (O. moubata and A. arboreus) probably acquired their FLEs separately, suggesting that the virulence attenuation observed in FLEs are not the consequence of a single acquisition event followed by speciation, but probably due to independent transitions of pathogenic francisellae into nonpathogenic FLEs within separate tick lineages. Additionally, we show that FLEs encode intact pathways for the production of several B vitamins and cofactors, denoting that they could function as nutrient-provisioning endosymbionts in ticks.
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Affiliation(s)
- Jonathan G Gerhart
- Biology Department and Center for Life in Extreme Environments, Portland State University
- Present address: Division of Parasitic Diseases and Malaria, Entomology Branch, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA
| | - H Auguste Dutcher
- Biology Department and Center for Life in Extreme Environments, Portland State University
| | - Amanda E Brenner
- Biology Department and Center for Life in Extreme Environments, Portland State University
| | - Abraham S Moses
- Biology Department and Center for Life in Extreme Environments, Portland State University
| | - Libor Grubhoffer
- Biology Centre CAS, Institute of Parasitology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Rahul Raghavan
- Biology Department and Center for Life in Extreme Environments, Portland State University
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parasitised feathered dinosaurs as revealed by Cretaceous amber assemblages. Nat Commun 2017; 8:1924. [PMID: 29233973 PMCID: PMC5727220 DOI: 10.1038/s41467-017-01550-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/27/2017] [Indexed: 11/08/2022] Open
Abstract
Ticks are currently among the most prevalent blood-feeding ectoparasites, but their feeding habits and hosts in deep time have long remained speculative. Here, we report direct and indirect evidence in 99 million-year-old Cretaceous amber showing that hard ticks and ticks of the extinct new family Deinocrotonidae fed on blood from feathered dinosaurs, non-avialan or avialan excluding crown-group birds. A †Cornupalpatum burmanicum hard tick is entangled in a pennaceous feather. Two deinocrotonids described as †Deinocroton draculi gen. et sp. nov. have specialised setae from dermestid beetle larvae (hastisetae) attached to their bodies, likely indicating cohabitation in a feathered dinosaur nest. A third conspecific specimen is blood-engorged, its anatomical features suggesting that deinocrotonids fed rapidly to engorgement and had multiple gonotrophic cycles. These findings provide insight into early tick evolution and ecology, and shed light on poorly known arthropod-vertebrate interactions and potential disease transmission during the Mesozoic.
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Mans BJ, Featherston J, de Castro MH, Pienaar R. Gene Duplication and Protein Evolution in Tick-Host Interactions. Front Cell Infect Microbiol 2017; 7:413. [PMID: 28993800 PMCID: PMC5622192 DOI: 10.3389/fcimb.2017.00413] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 09/06/2017] [Indexed: 01/01/2023] Open
Abstract
Ticks modulate their hosts' defense responses by secreting a biopharmacopiea of hundreds to thousands of proteins and bioactive chemicals into the feeding site (tick-host interface). These molecules and their functions evolved over millions of years as ticks adapted to blood-feeding, tick lineages diverged, and host-shifts occurred. The evolution of new proteins with new functions is mainly dependent on gene duplication events. Central questions around this are the rates of gene duplication, when they occurred and how new functions evolve after gene duplication. The current review investigates these questions in the light of tick biology and considers the possibilities of ancient genome duplication, lineage specific expansion events, and the role that positive selection played in the evolution of tick protein function. It contrasts current views in tick biology regarding adaptive evolution with the more general view that neutral evolution may account for the majority of biological innovations observed in ticks.
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Affiliation(s)
- Ben J Mans
- Epidemiology, Parasites and Vectors, Agricultural Research Council-Onderstepoort Veterinary ResearchOnderstepoort, South Africa.,Department of Veterinary Tropical Diseases, University of PretoriaPretoria, South Africa.,Department of Life and Consumer Sciences, University of South AfricaPretoria, South Africa
| | - Jonathan Featherston
- Agricultural Research Council-The Biotechnology PlatformOnderstepoort, South Africa
| | - Minique H de Castro
- Epidemiology, Parasites and Vectors, Agricultural Research Council-Onderstepoort Veterinary ResearchOnderstepoort, South Africa.,Department of Life and Consumer Sciences, University of South AfricaPretoria, South Africa.,Agricultural Research Council-The Biotechnology PlatformOnderstepoort, South Africa
| | - Ronel Pienaar
- Epidemiology, Parasites and Vectors, Agricultural Research Council-Onderstepoort Veterinary ResearchOnderstepoort, South Africa
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de Castro MH, de Klerk D, Pienaar R, Rees DJG, Mans BJ. Sialotranscriptomics of Rhipicephalus zambeziensis reveals intricate expression profiles of secretory proteins and suggests tight temporal transcriptional regulation during blood-feeding. Parasit Vectors 2017; 10:384. [PMID: 28797301 PMCID: PMC5553602 DOI: 10.1186/s13071-017-2312-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Ticks secrete a diverse mixture of secretory proteins into the host to evade its immune response and facilitate blood-feeding, making secretory proteins attractive targets for the production of recombinant anti-tick vaccines. The largely neglected tick species, Rhipicephalus zambeziensis, is an efficient vector of Theileria parva in southern Africa but its available sequence information is limited. Next generation sequencing has advanced sequence availability for ticks in recent years and has assisted the characterisation of secretory proteins. This study focused on the de novo assembly and annotation of the salivary gland transcriptome of R. zambeziensis and the temporal expression of secretory protein transcripts in female and male ticks, before the onset of feeding and during early and late feeding. RESULTS The sialotranscriptome of R. zambeziensis yielded 23,631 transcripts from which 13,584 non-redundant proteins were predicted. Eighty-six percent of these contained a predicted start and stop codon and were estimated to be putatively full-length proteins. A fifth (2569) of the predicted proteins were annotated as putative secretory proteins and explained 52% of the expression in the transcriptome. Expression analyses revealed that 2832 transcripts were differentially expressed among feeding time points and 1209 between the tick sexes. The expression analyses further indicated that 57% of the annotated secretory protein transcripts were differentially expressed. Dynamic expression profiles of secretory protein transcripts were observed during feeding of female ticks. Whereby a number of transcripts were upregulated during early feeding, presumably for feeding site establishment and then during late feeding, 52% of these were downregulated, indicating that transcripts were required at specific feeding stages. This suggested that secretory proteins are under stringent transcriptional regulation that fine-tunes their expression in salivary glands during feeding. No open reading frames were predicted for 7947 transcripts. This class represented 17% of the differentially expressed transcripts, suggesting a potential transcriptional regulatory function of long non-coding RNA in tick blood-feeding. CONCLUSIONS The assembled sialotranscriptome greatly expands the sequence availability of R. zambeziensis, assists in our understanding of the transcription of secretory proteins during blood-feeding and will be a valuable resource for future vaccine candidate selection.
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Affiliation(s)
- Minique Hilda de Castro
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa.,Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa.,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa
| | - Daniel de Klerk
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa
| | - Ronel Pienaar
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - D Jasper G Rees
- Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa.,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa
| | - Ben J Mans
- Epidemiology, Parasites and Vectors, Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa. .,College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, South Africa. .,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
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Valdés JJ, Cabezas-Cruz A, Sima R, Butterill PT, Růžek D, Nuttall PA. Substrate prediction of Ixodes ricinus salivary lipocalins differentially expressed during Borrelia afzelii infection. Sci Rep 2016; 6:32372. [PMID: 27584086 PMCID: PMC5008119 DOI: 10.1038/srep32372] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/05/2016] [Indexed: 11/13/2022] Open
Abstract
Evolution has provided ticks with an arsenal of bioactive saliva molecules that counteract host defense mechanisms. This salivary pharmacopoeia enables blood-feeding while enabling pathogen transmission. High-throughput sequencing of tick salivary glands has thus become a major focus, revealing large expansion within protein encoding gene families. Among these are lipocalins, ubiquitous barrel-shaped proteins that sequester small, typically hydrophobic molecules. This study was initiated by mining the Ixodes ricinus salivary gland transcriptome for specific, uncharacterized lipocalins: three were identified. Differential expression of these I. ricinus lipocalins during feeding at distinct developmental stages and in response to Borrelia afzelii infection suggests a role in transmission of this Lyme disease spirochete. A phylogenetic analysis using 803 sequences places the three I. ricinus lipocalins with tick lipocalins that sequester monoamines, leukotrienes and fatty acids. Both structural analysis and biophysical simulations generated robust predictions showing these I. ricinus lipocalins have the potential to bind monoamines similar to other tick species previously reported. The multidisciplinary approach employed in this study characterized unique lipocalins that play a role in tick blood-feeding and transmission of the most important tick-borne pathogen in North America and Eurasia.
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Affiliation(s)
- James J Valdés
- Institute of Parasitology, The Czech Academy of Sciences, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic
| | - Alejandro Cabezas-Cruz
- Center for Infection and Immunity of Lille (CIIL), INSERM U1019 - CNRS UMR 8204, Université Lille Nord de France, Institut Pasteur de Lille, Lille, France
| | - Radek Sima
- Institute of Parasitology, The Czech Academy of Sciences, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Philip T Butterill
- Biology Center, The Czech Academy of Sciences, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Daniel Růžek
- Institute of Parasitology, The Czech Academy of Sciences, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.,Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic.,Biology Center, The Czech Academy of Sciences, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
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