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Grandi G, Chiappa G, Ullman K, Lindgren PE, Olivieri E, Sassera D, Östlund E, Omazic A, Perissinotto D, Söderlund R. Characterization of the bacterial microbiome of Swedish ticks through 16S rRNA amplicon sequencing of whole ticks and of individual tick organs. Parasit Vectors 2023; 16:39. [PMID: 36717919 PMCID: PMC9885626 DOI: 10.1186/s13071-022-05638-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/24/2022] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The composition of the microbial flora associated with ixodid ticks has been studied in several species, revealing the importance of geographical origin, developmental stage(s) and feeding status of the tick, as well as substantial differences between tissues and organs. Studying the microbiome in the correct context and scale is therefore necessary for understanding the interactions between tick-borne pathogens and other microorganisms as well as other aspects of tick biology. METHODS In the present study the microbial flora of whole Ixodes ricinus, I. persulcatus and I. trianguliceps ticks were analyzed with 16S rRNA amplicon sequencing. Additionally, tick organs (midguts, Malpighian tubules, ovaries, salivary glands) from flat and engorged I. ricinus female ticks were examined with the same methodology. RESULTS The most abundant bacteria belonged to the group of Proteobacteria (Cand. Midichloria mitochondrii and Cand. Lariskella). 16S amplicon sequencing of dissected tick organs provided more information on the diversity of I. ricinus-associated microbial flora, especially when organs were collected from engorged ticks. Bacterial genera significantly associated with tick feeding status as well as genera associated with the presence of tick-borne pathogens were identified. CONCLUSIONS These results contribute to the knowledge of microbial flora associated with ixodid ticks in their northernmost distribution limit in Europe and opens new perspectives for other investigations on the function of these bacteria, including those using other approaches like in vitro cultivation and in vitro models.
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Affiliation(s)
- Giulio Grandi
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden ,grid.6341.00000 0000 8578 2742Department of Biomedical Sciences and Veterinary Public Health (BVF), Swedish University of Agricultural Sciences (SLU), Ulls Väg 26, 750 07 Uppsala, Sweden
| | - Giulia Chiappa
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
| | - Karin Ullman
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
| | - Per-Eric Lindgren
- grid.5640.70000 0001 2162 9922Department of Biomedical and Clinical Sciences, Division of Inflammation and Infection, Linköping University, 581 85 Linköping, Sweden ,grid.413253.2Department of Clinical Microbiology, County Hospital Ryhov, 551 85 Jönköping, Sweden
| | - Emanuela Olivieri
- grid.419583.20000 0004 1757 1598Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Strada Campeggi, 59/61, 27100 Pavia, Italy
| | - Davide Sassera
- grid.8982.b0000 0004 1762 5736Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Emma Östlund
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
| | - Anna Omazic
- grid.419788.b0000 0001 2166 9211Department of Chemistry, Environment, and Feed Hygiene, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
| | - Debora Perissinotto
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
| | - Robert Söderlund
- grid.419788.b0000 0001 2166 9211Department of Microbiology, National Veterinary Institute (SVA), 751 89 Uppsala, Sweden
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Militzer N, Pinecki Socias S, Nijhof AM. Changes in the Ixodes ricinus microbiome associated with artificial tick feeding. Front Microbiol 2023; 13:1050063. [PMID: 36704557 PMCID: PMC9871825 DOI: 10.3389/fmicb.2022.1050063] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Artificial tick feeding systems (ATFS) can be used to study tick biology and tick-pathogen interactions. Due to the long feeding duration of hard ticks, antibiotics are commonly added to the in vitro blood meal to prevent the blood from decaying. This may affect the ticks' microbiome, including mutualistic bacteria that play an important role in tick biology. This effect was examined by the consecutive feeding of Ixodes ricinus larvae, nymphs, and adults in vitro with and without the supplementation of gentamicin and in parallel on calves. DNA extracted from unfed females was analyzed by 16S rRNA sequencing. The abundance of Candidatus Midichloria mitochondrii, Rickettsia helvetica and Spiroplasma spp. was measured by qPCR in unfed larvae, nymphs, and adults. Larvae and nymphs fed on calves performed significantly better compared to both in vitro groups. Adults fed on blood supplemented with gentamicin and B vitamins had a higher detachment proportion and weight compared to the group fed with B vitamins but without gentamicin. The detachment proportion and weights of females did not differ significantly between ticks fed on calves and in vitro with gentamicin, but the fecundity was significantly higher in ticks fed on calves. 16S rRNA sequencing showed a higher microbiome species richness in ticks fed on calves compared to ticks fed in vitro. A shift in microbiome composition, with Ca. Midichloria mitochondrii as dominant species in females fed as juveniles on calves and R. helvetica as the most abundant species in females previously fed in vitro was observed. Females fed in vitro without gentamicin showed significant lower loads of Ca. M. mitochondrii compared to females fed in vitro with gentamicin and ticks fed on calves. Spiroplasma spp. were exclusively detected in female ticks fed on cattle by qPCR, but 16S rRNA sequencing results also showed a low abundance in in vitro females exposed to gentamicin. In conclusion, the employed feeding method and gentamicin supplementation affected the ticks' microbiome composition and fecundity. Since these changes may have an impact on tick biology and vector competence, they should be taken into account in studies employing ATFS.
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Affiliation(s)
- Nina Militzer
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Sophia Pinecki Socias
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Ard M. Nijhof
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany,Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany,*Correspondence: Ard M. Nijhof, ✉
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3
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Guizzo MG, Hatalová T, Frantová H, Zurek L, Kopáček P, Perner J. Ixodes ricinus ticks have a functional association with Midichloria mitochondrii. Front Cell Infect Microbiol 2023; 12:1081666. [PMID: 36699720 PMCID: PMC9868949 DOI: 10.3389/fcimb.2022.1081666] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023] Open
Abstract
In addition to being vectors of pathogenic bacteria, ticks also harbor intracellular bacteria that associate with ticks over generations, aka symbionts. The biological significance of such bacterial symbiosis has been described in several tick species but its function in Ixodes ricinus is not understood. We have previously shown that I. ricinus ticks are primarily inhabited by a single species of symbiont, Midichloria mitochondrii, an intracellular bacterium that resides and reproduces mainly in the mitochondria of ovaries of fully engorged I. ricinus females. To study the functional integration of M. mitochondrii into the biology of I. ricinus, an M. mitochondrii-depleted model of I. ricinus ticks was sought. Various techniques have been described in the literature to achieve dysbiosed or apo-symbiotic ticks with various degrees of success. To address the lack of a standardized experimental procedure for the production of apo-symbiotic ticks, we present here an approach utilizing the ex vivo membrane blood feeding system. In order to deplete M. mitochondrii from ovaries, we supplemented dietary blood with tetracycline. We noted, however, that the use of tetracycline caused immediate toxicity in ticks, caused by impairment of mitochondrial proteosynthesis. To overcome the tetracycline-mediated off-target effect, we established a protocol that leads to the production of an apo-symbiotic strain of I. ricinus, which can be sustained in subsequent generations. In two generations following tetracycline administration and tetracycline-mediated symbiont reduction, M. mitochondrii was gradually eliminated from the lineage. Larvae hatched from eggs laid by such M. mitochondrii-free females repeatedly performed poorly during blood-feeding, while the nymphs and adults performed similarly to controls. These data indicate that M. mitochondrii represents an integral component of tick ovarian tissue, and when absent, results in the formation of substandard larvae with reduced capacity to blood-feed.
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Affiliation(s)
- Melina Garcia Guizzo
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - Tereza Hatalová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia,Faculty of Science, University of South Bohemia, Ceske Budejovice, Czechia
| | - Helena Frantová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - Ludek Zurek
- CEITEC, University of Veterinary Sciences, Brno, Czechia,Department of Microbiology, Nutrition and Dietetics/CINeZ, Czech University of Life Sciences, Prague, Czechia,Department of Chemistry and Biochemistry, Mendel University, Brno, Czechia
| | - Petr Kopáček
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia
| | - Jan Perner
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czechia,*Correspondence: Jan Perner,
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Hoffman T, Olsen B, Lundkvist Å. The Biological and Ecological Features of Northbound Migratory Birds, Ticks, and Tick-Borne Microorganisms in the African-Western Palearctic. Microorganisms 2023; 11:microorganisms11010158. [PMID: 36677450 PMCID: PMC9866947 DOI: 10.3390/microorganisms11010158] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Identifying the species that act as hosts, vectors, and vehicles of vector-borne pathogens is vital for revealing the transmission cycles, dispersal mechanisms, and establishment of vector-borne pathogens in nature. Ticks are common vectors for pathogens causing human and animal diseases, and they transmit a greater variety of pathogenic agents than any other arthropod vector group. Ticks depend on the movements by their vertebrate hosts for their dispersal, and tick species with long feeding periods are more likely to be transported over long distances. Wild birds are commonly parasitized by ticks, and their migration patterns enable the long-distance range expansion of ticks. The African-Palearctic migration system is one of the world's largest migrations systems. African-Western Palearctic birds create natural links between the African, European, and Asian continents when they migrate biannually between breeding grounds in the Palearctic and wintering grounds in Africa and thereby connect different biomes. Climate is an important geographical determinant of ticks, and with global warming, the distribution range and abundance of ticks in the Western Palearctic may increase. The introduction of exotic ticks and their microorganisms into the Western Palearctic via avian vehicles might therefore pose a greater risk for the public and animal health in the future.
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Affiliation(s)
- Tove Hoffman
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
| | - Björn Olsen
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Zoonosis Science Center, Department of Medical Sciences, Uppsala University, 751 85 Uppsala, Sweden
| | - Åke Lundkvist
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
- Correspondence:
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Buysse M, Floriano AM, Gottlieb Y, Nardi T, Comandatore F, Olivieri E, Giannetto A, Palomar AM, Makepeace BL, Bazzocchi C, Cafiso A, Sassera D, Duron O. A dual endosymbiosis supports nutritional adaptation to hematophagy in the invasive tick Hyalomma marginatum. eLife 2021; 10:e72747. [PMID: 34951405 PMCID: PMC8709577 DOI: 10.7554/elife.72747] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/14/2021] [Indexed: 12/25/2022] Open
Abstract
Many animals are dependent on microbial partners that provide essential nutrients lacking from their diet. Ticks, whose diet consists exclusively on vertebrate blood, rely on maternally inherited bacterial symbionts to supply B vitamins. While previously studied tick species consistently harbor a single lineage of those nutritional symbionts, we evidence here that the invasive tick Hyalomma marginatum harbors a unique dual-partner nutritional system between an ancestral symbiont, Francisella, and a more recently acquired symbiont, Midichloria. Using metagenomics, we show that Francisella exhibits extensive genome erosion that endangers the nutritional symbiotic interactions. Its genome includes folate and riboflavin biosynthesis pathways but deprived functional biotin biosynthesis on account of massive pseudogenization. Co-symbiosis compensates this deficiency since the Midichloria genome encompasses an intact biotin operon, which was primarily acquired via lateral gene transfer from unrelated intracellular bacteria commonly infecting arthropods. Thus, in H. marginatum, a mosaic of co-evolved symbionts incorporating gene combinations of distant phylogenetic origins emerged to prevent the collapse of an ancestral nutritional symbiosis. Such dual endosymbiosis was never reported in other blood feeders but was recently documented in agricultural pests feeding on plant sap, suggesting that it may be a key mechanism for advanced adaptation of arthropods to specialized diets.
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Affiliation(s)
- Marie Buysse
- MIVEGEC (Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle), Univ. Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) - Institut pour la Recherche et le Développement (IRD)MontpellierFrance
- Centre of Research in Ecology and Evolution of Diseases (CREES), Montpellier, FranceMontpellierFrance
| | - Anna Maria Floriano
- Department of Biology and Biotechnology “L. Spallanzani”, University of PaviaPaviaItaly
- Faculty of Science, University of South BohemiaČeské BudějoviceCzech Republic
| | - Yuval Gottlieb
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of JerusalemRehovotIsrael
| | - Tiago Nardi
- Department of Biology and Biotechnology “L. Spallanzani”, University of PaviaPaviaItaly
| | - Francesco Comandatore
- Department of Biomedical and Clinical Sciences L. Sacco and Pediatric Clinical Research Center, University of MilanMilanItaly
| | - Emanuela Olivieri
- Department of Biology and Biotechnology “L. Spallanzani”, University of PaviaPaviaItaly
| | - Alessia Giannetto
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of MessinaMessinaItaly
| | - Ana M Palomar
- Center of Rickettsiosis and Arthropod-Borne Diseases (CRETAV), San Pedro University Hospital- Center of Biomedical Research from La Rioja (CIBIR)LogroñoSpain
| | - Benjamin L Makepeace
- Institute of Infection, Veterinary & Ecological Sciences, University of LiverpoolLiverpoolUnited Kingdom
| | | | | | - Davide Sassera
- Department of Biology and Biotechnology “L. Spallanzani”, University of PaviaPaviaItaly
| | - Olivier Duron
- MIVEGEC (Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle), Univ. Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) - Institut pour la Recherche et le Développement (IRD)MontpellierFrance
- Centre of Research in Ecology and Evolution of Diseases (CREES), Montpellier, FranceMontpellierFrance
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Arrais RC, Paula RC, Martins TF, Nieri-Bastos FA, Marcili A, Labruna MB. Survey of ticks and tick-borne agents in maned wolves (Chrysocyon brachyurus) from a natural landscape in Brazil. Ticks Tick Borne Dis 2020; 12:101639. [PMID: 33360385 DOI: 10.1016/j.ttbdis.2020.101639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 10/31/2020] [Accepted: 12/07/2020] [Indexed: 11/25/2022]
Abstract
This study evaluated ticks and tick-borne agents in 104 captures of the maned wolf Chrysocyon brachyurus (50 different individuals and 54 recaptures) in the Serra da Canastra National Park (SCNP), a Cerrado preserved area in southeastern Brazil, from 2005 to 2012. From the 104 capture events, a total of 1,206 ticks were collected on 94 occasions (90.4 %), and identified into five species: Amblyomma tigrinum (77.3 % of all collected ticks), Amblyomma sculptum (16.6 %), Amblyomma ovale (0.1 %), Amblyomma brasiliense (0.1 %), Rhipicephalus microplus (0.1 %), and Amblyomma spp. larvae (5.8 %). Molecular analyses of A. tigrinum adult ticks revealed the presence of 'Candidatus Rickettsia andeanae', Rickettsia parkeri sensu stricto, two different haplotypes of 'Ca. Midichloria sp.', and a Hepatozoon canis haplotype. Molecular analyses of maned wolf blood samples revealed two distinct haplotypes of Hepatozoon spp., one identical to the H. canis genotype that was detected in the A. tigrinum ticks, and a Hepatozoon americanum-like haplotype. None tick or blood samples yielded amplicons through PCR assays targeting the genera Ehrlichia, Anaplasma, Babesia, Rangelia, Cytauxzoon, and Theileria. Maned wolf serum samples were tested by immunofluorescence assay against antigens of five Rickettsia species (R. parkeri, R. rickettsii, R. amblyommatis, R. rhipicephali, and R. bellii) and Ehrlichia canis. Among 78 serum samples (45 captures plus 33 recaptures), 74 (95 %) were reactive to at least one Rickettsia species, with R. parkeri eliciting the highest endpoint titers. Some maned wolves that were recaptured during the study were shown to seroconvert to R. parkeri. Serum-reactiveness to E. canis was detected in 36 % (16/45) maned wolves. During the study, general clinical signs of tick-borne diseases were not found in any of the captured animals, indicating that they were under a good health status in the SCNP, despite of been exposed to ticks (mostly A. tigrinum) and some tick-borne agents (Rickettsia, Hepatozoon, Ehrlichia). The results of the present study might represent baseline data for the conservation of the maned wolf in its natural habitat, which should be used to interpret further studies about ticks and tick-borne diseases in maned wolves within human-modified landscapes.
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Affiliation(s)
- Ricardo C Arrais
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Rogério C Paula
- Centro Nacional de Pesquisa e Conservação de Mamíferos Carnívoros, Instituto Chico Mendes de Conservação da Biodiversidade, Ministério do Meio Ambiente, Atibaia, SP, Brazil
| | - Thiago F Martins
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil; Departamento de Laboratórios Especializados, Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, São Paulo, SP, Brazil
| | - Fernanda A Nieri-Bastos
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Arlei Marcili
- Programa de Pós-graduação em Medicina e Bem-Estar Animal e Saúde Única, Universidade Santo Amaro, R. Prof. Enéas de Siqueira Neto, 340 - Jardim das Imbuias, São Paulo, SP, 04829-300, Brazil
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil.
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Al-Khafaji AM, Armstrong SD, Varotto Boccazzi I, Gaiarsa S, Sinha A, Li Z, Sassera D, Carlow CKS, Epis S, Makepeace BL. Rickettsia buchneri, symbiont of the deer tick Ixodes scapularis, can colonise the salivary glands of its host. Ticks Tick Borne Dis 2019; 11:101299. [PMID: 31542229 DOI: 10.1016/j.ttbdis.2019.101299] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/02/2019] [Accepted: 09/07/2019] [Indexed: 12/25/2022]
Abstract
Vertically-transmitted bacterial symbionts are widespread in ticks and have manifold impacts on the epidemiology of tick-borne diseases. For instance, they may provide essential nutrients to ticks, affect vector competence, induce immune responses in vertebrate hosts, or even evolve to become vertebrate pathogens. The deer or blacklegged tick Ixodes scapularis harbours the symbiont Rickettsia buchneri in its ovarian tissues. Here we show by molecular, proteomic and imaging methods that R. buchneri is also capable of colonising the salivary glands of wild I. scapularis. This finding has important implications for the diagnosis of rickettsial infections and for pathogen-symbiont interactions in this notorious vector of Lyme borreliosis.
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Affiliation(s)
- Alaa M Al-Khafaji
- Institute of Infection & Global Health, University of Liverpool, Liverpool, UK; College of Veterinary Medicine, University of Al-Qadisiyah, Qadisiyyah Province, Iraq
| | - Stuart D Armstrong
- Institute of Infection & Global Health, University of Liverpool, Liverpool, UK
| | - Ilaria Varotto Boccazzi
- Department of Biosciences and Pediatric Clinical Research Center, University of Milan, Milan, Italy
| | - Stefano Gaiarsa
- Microbiology and Virology Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | | | - Zhiru Li
- New England Biolabs, Ipswich, MA, USA
| | - Davide Sassera
- Department of Biology & Biotechnology, University of Pavia, Pavia, Italy
| | | | - Sara Epis
- Department of Biosciences and Pediatric Clinical Research Center, University of Milan, Milan, Italy
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Buysse M, Duron O. Multi-locus phylogenetics of the Midichloria endosymbionts reveals variable specificity of association with ticks. Parasitology 2018; 145:1969-78. [PMID: 29779502 DOI: 10.1017/S0031182018000793] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Candidatus Midichloria mitochondrii is a maternally inherited bacterium of ticks with a unique intra-mitochondrial lifestyle. Here, we investigate on the evolutionary history of these associations and the degree of Midichloria-tick specificity. While previous surveys used the 16S rRNA gene as an exclusive molecular marker, we rather developed a multi-locus typing method based on four more variable housekeeping genes (groEL, rpoB, dnaK and ftsZ) and on one flagellum gene (fliC) present in Midichloria genomes. Using this method, multi-locus phylogenetic analyses revealed the structuring of a wide Midichloria genetic diversity into three distinct lineages associated with ticks. Overall, two distinct evolutionary strategies are obvious depending on lineage: two Midichloria lineages are generalists with infections acquired through horizontal transfers between distantly related tick species but one other Midichloria lineage rather show a high specificity degree to the Ixodes tick genus. This pattern suggests a capacity of certain Midichloria strains to maintain infections in only limited range of related tick species. These different infection strategies of Midichloria highlight an unexpected variability in their dependency to their tick hosts. We further conjecture that this pattern is also likely to indicate variability in their effects on ticks.
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