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Hussain S, Perveen N, Hussain A, Song B, Aziz MU, Zeb J, Li J, George D, Cabezas-Cruz A, Sparagano O. The Symbiotic Continuum Within Ticks: Opportunities for Disease Control. Front Microbiol 2022; 13:854803. [PMID: 35369485 PMCID: PMC8969565 DOI: 10.3389/fmicb.2022.854803] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 02/15/2022] [Indexed: 12/26/2022] Open
Abstract
Among blood-sucking arthropods, ticks are recognized as being of prime global importance because of their role as vectors of pathogens affecting human and animal health. Ticks carry a variety of pathogenic, commensal, and symbiotic microorganisms. For the latter, studies are available concerning the detection of endosymbionts, but their role in the physiology and ecology of ticks remains largely unexplored. This review paper focuses on tick endosymbionts of the genera Coxiella, Rickettsia, Francisella, Midichloria, and Wolbachia, and their impact on ticks and tick-pathogen interactions that drive disease risk. Tick endosymbionts can affect tick physiology by influencing nutritional adaptation, fitness, and immunity. Further, symbionts may influence disease ecology, as they interact with tick-borne pathogens and can facilitate or compete with pathogen development within the vector tissues. Rickettsial symbionts are frequently found in ticks of the genera of Ixodes, Amblyomma, and Dermacentor with relatively lower occurrence in Rhipicephalus, Haemaphysalis, and Hyalomma ticks, while Coxiella-like endosymbionts (CLEs) were reported infecting almost all tick species tested. Francisella-like endosymbionts (FLEs) have been identified in tick genera such as Dermacentor, Amblyomma, Ornithodoros, Ixodes, and Hyalomma, whereas Wolbachia sp. has been detected in Ixodes, Amblyomma, Hyalomma, and Rhipicephalus tick genera. Notably, CLEs and FLEs are obligate endosymbionts essential for tick survival and development through the life cycle. American dog ticks showed greater motility when infected with Rickettsia, indirectly influencing infection risk, providing evidence of a relationship between tick endosymbionts and tick-vectored pathogens. The widespread occurrence of endosymbionts across the tick phylogeny and evidence of their functional roles in ticks and interference with tick-borne pathogens suggests a significant contribution to tick evolution and/or vector competence. We currently understand relatively little on how these endosymbionts influence tick parasitism, vector capacity, pathogen transmission and colonization, and ultimately on how they influence tick-borne disease dynamics. Filling this knowledge gap represents a major challenge for future research.
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Affiliation(s)
- Sabir Hussain
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Nighat Perveen
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Abrar Hussain
- Department of Epidemiology and Public Health, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Baolin Song
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Muhammad Umair Aziz
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Jehan Zeb
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Jun Li
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - David George
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alejandro Cabezas-Cruz
- Anses, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, France
| | - Olivier Sparagano
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China
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2
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Beliavskaia A, Hönig V, Erhart J, Vyhlidalova T, Palus M, Cerny J, Kozlova I, Ruzek D, Palomar AM, Bell-Sakyi L. Spiroplasma Isolated From Third-Generation Laboratory Colony Ixodes persulcatus Ticks. Front Vet Sci 2021; 8:659786. [PMID: 33842580 PMCID: PMC8032855 DOI: 10.3389/fvets.2021.659786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/26/2021] [Indexed: 12/30/2022] Open
Abstract
Spiroplasma are vertically-transmitted endosymbionts of ticks and other arthropods. Field-collected Ixodes persulcatus have been reported to harbour Spiroplasma, but nothing is known about their persistence during laboratory colonisation of this tick species. We successfully isolated Spiroplasma from internal organs of 6/10 unfed adult ticks, belonging to the third generation of an I. persulcatus laboratory colony, into tick cell culture. We screened a further 51 adult male and female ticks from the same colony for presence of Spiroplasma by genus-specific PCR amplification of fragments of the 16S rRNA and rpoB genes; 100% of these ticks were infected and the 16S rRNA sequence showed 99.8% similarity to that of a previously-published Spiroplasma isolated from field-collected I. persulcatus. Our study shows that Spiroplasma endosymbionts persist at high prevalence in colonised I. persulcatus through at least three generations, and confirms the usefulness of tick cell lines for isolation and cultivation of this bacterium.
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Affiliation(s)
- Alexandra Beliavskaia
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Vaclav Hönig
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia.,Veterinary Research Institute, Brno, Czechia
| | - Jan Erhart
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
| | - Tereza Vyhlidalova
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
| | - Martin Palus
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia.,Veterinary Research Institute, Brno, Czechia
| | - Jiri Cerny
- Centre for Infectious Animal Diseases, Faculty of Tropical AgriSciences, Czech University of Life Sciences, Prague, Czechia
| | - Irina Kozlova
- Science Center for Family Health and Human Reproduction Problems, Irkutsk, Russia
| | - Daniel Ruzek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia.,Veterinary Research Institute, Brno, Czechia
| | - Ana M Palomar
- Centre of Rickettsiosis and Arthropod-Borne Diseases, Hospital Universitario San Pedro-CIBIR, Logroño, Spain
| | - Lesley Bell-Sakyi
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
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3
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Kotsarenko K, Vechtova P, Lieskovska J, Füssy Z, Cabral-de-Mello DC, Rego ROM, Alberdi P, Collins M, Bell-Sakyi L, Sterba J, Grubhoffer L. Karyotype changes in long-term cultured tick cell lines. Sci Rep 2020; 10:13443. [PMID: 32778731 PMCID: PMC7417564 DOI: 10.1038/s41598-020-70330-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/20/2020] [Indexed: 01/08/2023] Open
Abstract
Tick cell lines are an easy-to-handle system for the study of viral and bacterial infections and other aspects of tick cellular processes. Tick cell cultures are often continuously cultivated, as freezing can affect their viability. However, the long-term cultivation of tick cells can influence their genome stability. In the present study, we investigated karyotype and genome size of tick cell lines. Though 16S rDNA sequencing showed the similarity between Ixodes spp. cell lines at different passages, their karyotypes differed from 2n = 28 chromosomes for parental Ixodes spp. ticks, and both increase and decrease in chromosome numbers were observed. For example, the highly passaged Ixodes scapularis cell line ISE18 and Ixodes ricinus cell lines IRE/CTVM19 and IRE/CTVM20 had modal chromosome numbers 48, 23 and 48, respectively. Also, the Ornithodoros moubata cell line OME/CTVM22 had the modal chromosome number 33 instead of 2n = 20 chromosomes for Ornithodoros spp. ticks. All studied tick cell lines had a larger genome size in comparison to the genomes of the parental ticks. Thus, highly passaged tick cell lines can be used for research purposes, but possible differences in encoded genetic information and downstream cellular processes, between different cell populations, should be taken into account.
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Affiliation(s)
- Kateryna Kotsarenko
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic. .,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic. .,Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic.
| | - Pavlina Vechtova
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Jaroslava Lieskovska
- Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Zoltán Füssy
- Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Diogo C Cabral-de-Mello
- Department of General and Applied Biology, São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Ryan O M Rego
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Pilar Alberdi
- Neuroplasticity and Neurodegeneration Group, Regional Center for Biomedical Research (CRIB), Ciudad Real Medical School, University of Castilla-La Mancha, 13005, Ciudad Real, Spain
| | - Marisol Collins
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L3 5RF, UK
| | - Lesley Bell-Sakyi
- Department of Infection Biology and Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L3 5RF, UK
| | - Jan Sterba
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Libor Grubhoffer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
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4
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Palomar AM, Premchand-Branker S, Alberdi P, Belova OA, Moniuszko-Malinowska A, Kahl O, Bell-Sakyi L. Isolation of known and potentially pathogenic tick-borne microorganisms from European ixodid ticks using tick cell lines. Ticks Tick Borne Dis 2019; 10:628-638. [PMID: 30819609 PMCID: PMC6446187 DOI: 10.1016/j.ttbdis.2019.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/07/2019] [Accepted: 02/18/2019] [Indexed: 12/14/2022]
Abstract
Ticks harbour and, in many cases transmit to their vertebrate hosts, a wide variety of pathogenic, apathogenic and endosymbiotic microorganisms. Recent molecular analyses have greatly increased the range of bacterial species potentially associated with ticks, but in most cases cannot distinguish between surface contaminants, microorganisms present in the remains of the previous blood meal and truly intracellular or tissue-associated bacteria. Here we demonstrate how tick cell lines, primary cell cultures and organ cultures can be used to isolate and propagate bacteria from within embryonic and adult Ixodes ricinus, Dermacentor marginatus and Dermacentor reticulatus ticks originating from different parts of Europe. We isolated and partially characterised four new strains of Spiroplasma from The Netherlands, Spain and Poland, two new strains of Rickettsia raoultii from Russia and Poland, one strain of Rickettsia slovaca from Spain and a species of Mycobacterium from the UK. Comparison with published sequences showed that the Spiroplasma strains were closely related to Spiroplasma ixodetis and the Mycobacterium isolate belonged to the Mycobacterium chelonae complex, while the R. raoultii and R. slovaca strains were similar to previously-validated species.
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Affiliation(s)
- Ana M Palomar
- Centre of Rickettsiosis and Arthropod-Borne Diseases, CIBIR, C/ Piqueras, 98, Logroño 26006, La Rioja, Spain; The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK.
| | - Shonnette Premchand-Branker
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
| | - Pilar Alberdi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
| | - Oxana A Belova
- Chumakov Institute of Poliomyelitis and Viral Encephalitides (Chumakov FSC R&D IBP RAS), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108819, Russia; Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, 20-1 Malaya Pirogovskaya St., Moscow 119435, Russia.
| | - Anna Moniuszko-Malinowska
- Department of Infectious Diseases and Neuroinfections, Medical University in Białystok, Zurawia 14, 15-540 Białystok, Poland.
| | - Olaf Kahl
- Tick-radar GmbH, 10555 Berlin, Germany.
| | - Lesley Bell-Sakyi
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK; Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool L3 5RF, UK.
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5
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Bell-Sakyi L, Darby A, Baylis M, Makepeace BL. The Tick Cell Biobank: A global resource for in vitro research on ticks, other arthropods and the pathogens they transmit. Ticks Tick Borne Dis 2018; 9:1364-1371. [PMID: 29886187 PMCID: PMC6052676 DOI: 10.1016/j.ttbdis.2018.05.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/18/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022]
Abstract
Tick cell lines are increasingly used in many fields of tick and tick-borne disease research. The Tick Cell Biobank was established in 2009 to facilitate the development and uptake of these unique and valuable resources. As well as serving as a repository for existing and new ixodid and argasid tick cell lines, the Tick Cell Biobank supplies cell lines and training in their maintenance to scientists worldwide and generates novel cultures from tick species not already represented in the collection. Now part of the Institute of Infection and Global Health at the University of Liverpool, the Tick Cell Biobank has embarked on a new phase of activity particularly targeted at research on problems caused by ticks, other arthropods and the diseases they transmit in less-developed, lower- and middle-income countries. We are carrying out genotypic and phenotypic characterisation of selected cell lines derived from tropical tick species. We continue to expand the culture collection, currently comprising 63 cell lines derived from 18 ixodid and argasid tick species and one each from the sand fly Lutzomyia longipalpis and the biting midge Culicoides sonorensis, and are actively engaging with collaborators to obtain starting material for primary cell cultures from other midge species, mites, tsetse flies and bees. Outposts of the Tick Cell Biobank will be set up in Malaysia, Kenya and Brazil to facilitate uptake and exploitation of cell lines and associated training by scientists in these and neighbouring countries. Thus the Tick Cell Biobank will continue to underpin many areas of global research into biology and control of ticks, other arthropods and vector-borne viral, bacterial and protozoan pathogens.
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Affiliation(s)
- Lesley Bell-Sakyi
- Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom.
| | - Alistair Darby
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, United Kingdom.
| | - Matthew Baylis
- Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom; NIHR Health Protection Research Institute in Emerging and Zoonotic Infections, Institute of Infection and Global Health, University of Liverpool, The Ronald Ross Building, 8 West Derby Street, Liverpool L69 7BE, United Kingdom.
| | - Benjamin L Makepeace
- Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool L3 5RF, United Kingdom.
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6
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Tomassone L, Portillo A, Nováková M, de Sousa R, Oteo JA. Neglected aspects of tick-borne rickettsioses. Parasit Vectors 2018; 11:263. [PMID: 29690900 PMCID: PMC5937841 DOI: 10.1186/s13071-018-2856-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/18/2018] [Indexed: 11/26/2022] Open
Abstract
Rickettsioses are among the oldest known infectious diseases. In spite of this, and of the extensive research carried out, many aspects of the biology and epidemiology of tick-borne rickettsiae are far from being completely understood. Their association with arthropod vectors, the importance of vertebrates as reservoirs, the rarity of clinical signs in animals, or the interactions of pathogenic species with rickettsial endosymbionts and with the host intracellular environment, are only some examples. Moreover, new rickettsiae are continuously being discovered. In this review, we focus on the ‘neglected’ aspects of tick-borne rickettsioses and on the gaps in knowledge, which could help to explain why these infections are still emerging and re-emerging threats worldwide.
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Affiliation(s)
- Laura Tomassone
- Department of Veterinary Sciences, University of Turin, Largo Braccini 2, 10095, Grugliasco (Torino), Italy.
| | - Aránzazu Portillo
- Center of Rickettsiosis and Arthropod-Borne Diseases, Hospital San Pedro-CIBIR, C/ Piqueras 98, 26006, Logroño, Spain
| | - Markéta Nováková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.,Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého 1946/1, 612 42, Brno, Czech Republic
| | - Rita de Sousa
- National Institute of Health Dr. Ricardo Jorge, Av. da Liberdade 5, 2965-575, Aguas de Moura, Portugal
| | - José Antonio Oteo
- Center of Rickettsiosis and Arthropod-Borne Diseases, Hospital San Pedro-CIBIR, C/ Piqueras 98, 26006, Logroño, Spain
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7
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Dupraz M, Toty C, Devillers E, Blanchon T, Elguero E, Vittecoq M, Moutailler S, McCoy KD. Population structure of the soft tick Ornithodoros maritimus and its associated infectious agents within a colony of its seabird host Larus michahellis. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2017; 6:122-130. [PMID: 28620577 PMCID: PMC5460746 DOI: 10.1016/j.ijppaw.2017.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 01/11/2023]
Abstract
The epidemiology of vector-borne zoonoses depends on the movement of both hosts and vectors, which can differ greatly in intensity across spatial scales. Because of their life history traits and small size, vector dispersal may be frequent, but limited in distance. However, little information is available on vector movement patterns at local spatial scales, and particularly for ticks, transmitting the greatest diversity of recognized infectious agents. To test the degree to which ticks can disperse and disseminate pathogens at local scales, we investigated the temporal dynamics and population structure of the soft tick Ornithodoros maritimus within a colony of its seabird host, the Yellow-legged gull Larus michahellis. Ticks were repeatedly sampled at a series of nests during the host breeding season. In half of the nests, ticks were collected (removal sampling), in the other half, ticks were counted and returned to the nest. A subsample of ticks was screened for known bacteria, viruses and parasites using a high throughput real-time PCR system to examine their distribution within the colony. The results indicate a temporal dynamic in the presence of tick life stages over the season, with the simultaneous appearance of juvenile ticks and hatched chicks, but no among-nest spatial structure in tick abundance. Removal sampling significantly reduced tick numbers, but only from the fourth visit onward. Seven bacterial isolates, one parasite species and one viral isolate were detected but no spatial structure in their presence within the colony was found. These results suggest weak isolation among nests and that tick dispersal is likely frequent enough to quickly recolonize locally-emptied patches and disseminate pathogens across the colony. Vector-mediated movements at local scales may therefore play a key role in pathogen emergence and needs to be considered in conjunction with host movements for predicting pathogen circulation and for establishing effective control strategies. A temporal dynamic in the abundance of tick stages was found over the season. Destructive sampling reduced tick abundance near the end of the sampling period. No spatial structure in the ticks or infectious agents was detected. Relatively frequent tick movements among nests were suggested.
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Affiliation(s)
- Marlene Dupraz
- MIVEGEC UMR 5290 CNRS IRD UM, Centre IRD, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France
- Corresponding author.
| | - Céline Toty
- MIVEGEC UMR 5290 CNRS IRD UM, Centre IRD, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Elodie Devillers
- UMR Bipar, Anses, INRA, ENVA, 14 Rue Pierre et Marie Curie, 94700 Maisons-Alfort, France
| | - Thomas Blanchon
- Centre de recherche de la Tour du Valat, 13200 Arles, France
| | - Eric Elguero
- MIVEGEC UMR 5290 CNRS IRD UM, Centre IRD, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France
| | - Marion Vittecoq
- Centre de recherche de la Tour du Valat, 13200 Arles, France
| | - Sara Moutailler
- UMR Bipar, Anses, INRA, ENVA, 14 Rue Pierre et Marie Curie, 94700 Maisons-Alfort, France
| | - Karen D. McCoy
- MIVEGEC UMR 5290 CNRS IRD UM, Centre IRD, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France
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8
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Fluorescent Protein Expressing Rickettsia buchneri and Rickettsia peacockii for Tracking Symbiont-Tick Cell Interactions. Vet Sci 2016; 3:vetsci3040034. [PMID: 29056742 PMCID: PMC5606589 DOI: 10.3390/vetsci3040034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 11/28/2022] Open
Abstract
Rickettsiae of indeterminate pathogenicity are widely associated with ticks. The presence of these endosymbionts can confound a One Health approach to combatting tick-borne diseases. Genomic analyses of symbiotic rickettsiae have revealed that they harbor mutations in gene coding for proteins involved in rickettsial pathogenicity and motility. We have isolated and characterized two rickettsial symbionts—Rickettsia peacockii and R. buchneri—both from ticks using tick cell cultures. To better track these enigmatic rickettsiae in ticks and at the tick-mammal interface we transformed the rickettsiae to express fluorescent proteins using shuttle vectors based on rickettsial plasmids or a transposition system driving insertional mutagenesis. Fluorescent protein expressing R. buchneri and R. peacockii will enable us to elucidate their interactions with tick and mammalian cells, and track their location and movement within individual cells, vector ticks, and host animals.
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9
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Grandeur Alliances: Symbiont Metabolic Integration and Obligate Arthropod Hematophagy. Trends Parasitol 2016; 32:739-749. [PMID: 27236581 DOI: 10.1016/j.pt.2016.05.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/05/2016] [Accepted: 05/06/2016] [Indexed: 01/15/2023]
Abstract
Several arthropod taxa live exclusively on vertebrate blood. This food source lacks essential metabolites required for the maintenance of metabolic homeostasis, and as such, these arthropods have formed symbioses with nutrient-supplementing microbes that facilitate their host's 'hematophagous' feeding ecology. Herein we highlight metabolic contributions of bacterial symbionts that reside within tsetse flies, bed bugs, lice, reduviid bugs, and ticks, with specific emphasis on B vitamin and cofactor biosynthesis. Importantly, these arthropods can transmit pathogens of medical and veterinary relevance and/or cause infestations that induce psychological and dermatological distress. Microbial metabolites, and the biochemical pathways that generate them, can serve as specific targets of novel control mechanisms aimed at disrupting the metabolism of hematophagous arthropods, thus combatting pest invasion and vector-borne pathogen transmission.
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10
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Abstract
Rickettsia felis is an emerging insect-borne rickettsial pathogen and the causative agent of flea-borne spotted fever. First described as a human pathogen from the USA in 1991, R. felis is now identified throughout the world and considered a common cause of fever in Africa. The cosmopolitan distribution of this pathogen is credited to the equally widespread occurrence of cat fleas (Ctenocephalides felis), the primary vector and reservoir of R. felis. Although R. felis is a relatively new member of the pathogenic Rickettsia, limited knowledge of basic R. felis biology continues to hinder research progression of this unique bacterium. This is a comprehensive review examining what is known and unknown relative to R. felis transmission biology, epidemiology of the disease, and genetics, with an insight into areas of needed investigation.
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Affiliation(s)
- Lisa D. Brown
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, SVM-3213, Baton Rouge, LA 70803 USA
| | - Kevin R. Macaluso
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, SVM-3213, Baton Rouge, LA 70803 USA
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11
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Dietrich M, Lebarbenchon C, Jaeger A, Le Rouzic C, Bastien M, Lagadec E, McCoy KD, Pascalis H, Le Corre M, Dellagi K, Tortosa P. Rickettsia spp. in seabird ticks from western Indian Ocean islands, 2011-2012. Emerg Infect Dis 2014; 20:838-42. [PMID: 24751287 PMCID: PMC4012800 DOI: 10.3201/eid2005.131088] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.
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Sentausa E, El Karkouri K, Nguyen TT, Caputo A, Raoult D, Fournier PE. Genome Sequence of Rickettsia hoogstraalii, a Geographically Widely Distributed Tick-Associated Bacterium. GENOME ANNOUNCEMENTS 2014; 2:e01171-14. [PMID: 25377719 PMCID: PMC4223470 DOI: 10.1128/genomea.01171-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/02/2014] [Indexed: 11/29/2022]
Abstract
Rickettsia hoogstraalii is a tick-associated member of the spotted fever group rickettsiae that is geographically widely distributed. We report here the draft genome of R. hoogstraalii strain Croatica(T) (=DSM 22243 = UTMB 00003), which was isolated from Haemaphysalis sulcata ticks collected in Croatia.
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Affiliation(s)
- Erwin Sentausa
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
| | - Khalid El Karkouri
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
| | - Thi-Tien Nguyen
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
| | - Aurélia Caputo
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
| | - Didier Raoult
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
| | - Pierre-Edouard Fournier
- Aix-Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM U1095, Faculte de Medecine, Marseille, France
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Motility characteristics are altered for Rickettsia bellii transformed to overexpress a heterologous rickA gene. Appl Environ Microbiol 2013; 80:1170-6. [PMID: 24296498 DOI: 10.1128/aem.03352-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The rickettsial protein RickA activates host cell factors associated with the eukaryotic actin cytoskeleton and is likely involved with rickettsial host cell binding and infection and the actin-based motility of spotted fever group rickettsiae. The rickA gene sequence and protein vary substantially between Rickettsia species, as do observed motility-associated phenotypes. To help elucidate the function of RickA and determine the effects of species-specific RickA variations, we compared extracellular binding, intracellular motility, and intercellular spread phenotypes of three Rickettsia bellii variants. These included two shuttle vector-transformed R. bellii strains and the wild-type isolate from which they were derived, R. bellii RML 369C. Both plasmid shuttle vectors carried spectinomycin resistance and a GFPuv reporter; one contained Rickettsia monacensis-derived rickA, and the other lacked the rickA gene. Rickettsia bellii transformed to express R. monacensis rickA highly overexpressed this transcript in comparison to its native rickA. These rickettsiae also moved at higher velocities and followed a more curved path than the negative-control transformants. A lower proportion of R. monacensis rickA-expressing bacteria ever became motile, however, and they formed smaller plaques.
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Melničáková J, Derdáková M, Barák I. A system to simultaneously detect tick-borne pathogens based on the variability of the 16S ribosomal genes. Parasit Vectors 2013; 6:269. [PMID: 24330462 PMCID: PMC3850910 DOI: 10.1186/1756-3305-6-269] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/12/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND DNA microarrays can be used to quickly and sensitively identify several different pathogens in one step. Our previously developed DNA microarray, based on the detection of variable regions in the 16S rDNA gene (rrs), which are specific for each selected bacterial genus, allowed the concurrent detection of Borrelia spp., Anaplasma spp., Francisella spp., Rickettsia spp. and Coxiella spp. METHODS In this study, we developed a comprehensive detection system consisting of a second generation DNA microarray and quantitative PCRs. New oligonucleotide capture probes specific for Borrelia burgdorferi s.l. genospecies and Candidatus Neoehrlichia mikurensis were included. This new DNA microarray system required substantial changes in solution composition, hybridization conditions and post-hybridization washes. RESULTS This second generation chip displayed high specificity and sensitivity. The specificity of the capture probes was tested by hybridizing the DNA microarrays with Cy5-labeled, PCR-generated amplicons encoding the rrs genes of both target and non-target bacteria. The detection limit was determined to be 10(3) genome copies, which corresponds to 1-2 pg of DNA. A given sample was evaluated as positive if its mean fluorescence was at least 10% of the mean fluorescence of a positive control. Those samples with fluorescence close to the threshold were further analyzed using quantitative PCRs, developed to identify Francisella spp., Rickettsia spp. and Coxiella spp. Like the DNA microarray, the qPCRs were based on the genus specific variable regions of the rrs gene. No unspecific cross-reactions were detected. The detection limit for Francisella spp. was determined to be only 1 genome copy, for Coxiella spp. 10 copies, and for Rickettsia spp., 100 copies. CONCLUSIONS Our detection system offers a rapid method for the comprehensive identification of tick-borne bacteria, which is applicable to clinical samples. It can also be used to identify both pathogenic and endosymbiontic bacteria in ticks for eco-epidemiological studies, tick laboratory colony testing, and many other applications.
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Bell-Sakyi L, Attoui H. Endogenous tick viruses and modulation of tick-borne pathogen growth. Front Cell Infect Microbiol 2013; 3:25. [PMID: 23875176 PMCID: PMC3709243 DOI: 10.3389/fcimb.2013.00025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/12/2013] [Indexed: 12/28/2022] Open
Abstract
Ticks transmit a wide range of viral, bacterial and protozoan pathogens, many of which can establish persistent infections of lifelong duration in the vector tick and in some cases are transmitted transovarially to the next generation. In addition many ixodid and argasid tick cell lines and, by inference the parent ticks from which they were derived, harbor endogenous viruses (ETV) of which almost nothing is known. In general, low level persistent infections with viral pathogens (arboviruses) are not known to have a deleterious effect on tick survival and fitness, suggesting that they can strike a balance with the tick innate immune response. This tolerance of arbovirus infection may be modulated by the permanent presence of ETV in the host cell. In mosquito cells, temporary or permanent silencing of the genes of an endogenous virus by RNA interference can result in changes in replication rate of a co-infecting arbovirus. We propose that tick cell lines offer a useful model system for in vitro investigation of the modulatory effect of ETV on superinfecting pathogen survival and replication in ticks, using the molecular manipulation techniques applied to insect cells.
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Affiliation(s)
- Lesley Bell-Sakyi
- *Correspondence: Lesley Bell-Sakyi and Houssam Attoui, The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK e-mail: ;
| | - Houssam Attoui
- *Correspondence: Lesley Bell-Sakyi and Houssam Attoui, The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK e-mail: ;
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Socolovschi C, Kernif T, Raoult D, Parola P. Borrelia, Rickettsia, and Ehrlichia species in bat ticks, France, 2010. Emerg Infect Dis 2013; 18:1966-75. [PMID: 23171714 PMCID: PMC3557878 DOI: 10.3201/eid1812.111237] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Physicians should consider infections with these bacteria in patients who may
have been bitten by bat ticks. Argas vespertilionis, an argasid tick associated with bats and
bat habitats in Europe, Africa, and Asia has been reported to bite humans;
however, studies investigating the presence of vector-borne pathogens in these
ticks are lacking. Using molecular tools, we tested 5 A.
vespertilionis ticks collected in 2010 from the floor of a
bat-infested attic in southwestern France that had been converted into bedrooms.
Rickettsia sp. AvBat, a new genotype of spotted fever group
rickettsiae, was detected and cultivated from 3 of the 5 ticks. A new species of
the Ehrlichia canis group, Ehrlichia sp.
AvBat, was also detected in 3 ticks. Four ticks were infected with
Borrelia sp. CPB1, a relapsing fever agent of the
Borrelia group that caused fatal borreliosis in a bat in
the United Kingdom. Further studies are needed to characterize these new agents
and determine if the A. vespertilionis tick is a vector and/or
reservoir of these agents.
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Affiliation(s)
- Cristina Socolovschi
- Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, Marseille, France
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Alberdi MP, Nijhof AM, Jongejan F, Bell-Sakyi L. Tick cell culture isolation and growth of Rickettsia raoultii from Dutch Dermacentor reticulatus ticks. Ticks Tick Borne Dis 2012; 3:349-54. [PMID: 23140894 PMCID: PMC3528949 DOI: 10.1016/j.ttbdis.2012.10.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Tick cell lines play an important role in research on ticks and tick-borne pathogenic and symbiotic microorganisms. In an attempt to derive continuous Dermacentor reticulatus cell lines, embryo-derived primary cell cultures were set up from eggs laid by field ticks originally collected as unfed adults in The Netherlands and maintained for up to 16 months. After several months, it became evident that cells in the primary cultures were infected with a Rickettsia-like intracellular organism. Supernatant medium containing some D. reticulatus cells was inoculated into cultures of 2 Rhipicephalus (Boophilus) microplus cell lines, BME/CTVM2 and BME/CTVM23, where abundant growth of the bacteria occurred intracellularly on transfer to both cell lines. Bacterial growth was monitored by light (live, inverted microscope, Giemsa-stained cytocentrifuge smears) and transmission electron microscopy revealing heavy infection with typical intracytoplasmic Rickettsia-like bacteria, not present in uninfected cultures. DNA was extracted from bacteria-infected and uninfected control cultures, and primers specific for Rickettsia 16S rRNA, ompB, and sca4 genes were used to generate PCR products that were subsequently sequenced. D. reticulatus primary cultures and both infected tick cell lines were positive for all 3 Rickettsia genes. Sequencing of PCR products revealed 99–100% identity with published Rickettsia raoultii sequences. The R. raoultii also grew abundantly in the D. nitens cell line ANE58, poorly in the D. albipictus cell line DALBE3, and not at all in the D. andersoni cell line DAE15. In conclusion, primary tick cell cultures and cell lines are useful systems for isolation and propagation of fastidious tick-borne microorganisms. In vitro isolation of R. raoultii from Dutch D. reticulatus confirms previous PCR-based detection in field ticks, and presence of the bacteria in the tick eggs used to initiate the primary cultures confirms that transovarial transmission of this Rickettsia occurs.
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Affiliation(s)
- M Pilar Alberdi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.
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Bell-Sakyi L, Kohl A, Bente DA, Fazakerley JK. Tick cell lines for study of Crimean-Congo hemorrhagic fever virus and other arboviruses. Vector Borne Zoonotic Dis 2012; 12:769-81. [PMID: 21955214 PMCID: PMC3438810 DOI: 10.1089/vbz.2011.0766] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Continuous cell lines derived from many of the vectors of tick-borne arboviruses of medical and veterinary importance are now available. Their role as tools in arbovirus research to date is reviewed and their potential application in studies of tick cell responses to virus infection is explored, by comparison with recent progress in understanding mosquito immunity to arbovirus infection. A preliminary study of propagation of the human pathogen Crimean-Congo hemorrhagic fever virus (CCHFV) in tick cell lines is reported; CCHFV replicated in seven cell lines derived from the ticks Hyalomma anatolicum (a known vector), Amblyomma variegatum, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus (Boophilus) microplus, and Ixodes ricinus, but not in three cell lines derived from Rhipicephalus appendiculatus and Ornithodoros moubata. This indicates that tick cell lines can be used to study growth of CCHFV in arthropod cells and that there may be species-specific restriction in permissive CCHFV infection at the cellular level.
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Affiliation(s)
- Lesley Bell-Sakyi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom.
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Alberdi MP, Dalby MJ, Rodriguez-Andres J, Fazakerley JK, Kohl A, Bell-Sakyi L. Detection and identification of putative bacterial endosymbionts and endogenous viruses in tick cell lines. Ticks Tick Borne Dis 2012; 3:137-46. [PMID: 22743047 PMCID: PMC3431536 DOI: 10.1016/j.ttbdis.2012.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 05/28/2012] [Accepted: 05/30/2012] [Indexed: 11/24/2022]
Abstract
As well as being vectors of many viral, bacterial, and protozoan pathogens of medical and veterinary importance, ticks harbour a variety of microorganisms which are not known to be pathogenic for vertebrate hosts. Continuous cell lines established from ixodid and argasid ticks could be infected with such endosymbiotic bacteria and endogenous viruses, but to date very few cell lines have been examined for their presence. DNA and RNA extracted from over 50 tick cell lines deposited in the Roslin Wellcome Trust Tick Cell Biobank (http://tickcells.roslin.ac.uk) were screened for presence of bacteria and RNA viruses, respectively. Sequencing of PCR products amplified using pan-16S rRNA primers revealed the presence of DNA sequences from bacterial endosymbionts in several cell lines derived from Amblyomma and Dermacentor spp. ticks. Identification to species level was attempted using Rickettsia- and Francisella-specific primers. Pan-Nairovirus primers amplified PCR products of uncertain specificity in cell lines derived from Rhipicephalus, Hyalomma, Ixodes, Carios, and Ornithodoros spp. ticks. Further characterisation attempted with primers specific for Crimean-Congo haemorrhagic fever virus segments confirmed the absence of this arbovirus in the cells. A set of pan-Flavivirus primers did not detect endogenous viruses in any of the cell lines. Transmission electron microscopy revealed the presence of endogenous reovirus-like viruses in many of the cell lines; only 4 of these lines gave positive results with primers specific for the tick Orbivirus St Croix River virus, indicating that there may be additional, as yet undescribed 'tick-only' viruses inhabiting tick cell lines.
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Affiliation(s)
- M Pilar Alberdi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.
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Lallinger G, Zweygarth E, Bell-Sakyi L, Passos LM. Cold storage and cryopreservation of tick cell lines. Parasit Vectors 2010; 3:37. [PMID: 20388200 PMCID: PMC2861667 DOI: 10.1186/1756-3305-3-37] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 04/13/2010] [Indexed: 11/25/2022] Open
Abstract
Background Tick cell lines are now available from fifteen ixodid and argasid species of medical and veterinary importance. However, some tick cell lines can be difficult to cryopreserve, and improved protocols for short- and long-term low temperature storage will greatly enhance their use as tools in tick and tick-borne pathogen research. In the present study, different protocols were evaluated for cold storage and cryopreservation of tick cell lines derived from Rhipicephalus (Boophilus) decoloratus, Rhipicephalus (Boophilus) microplus, Ixodes ricinus and Ixodes scapularis. For short-term cold storage, cells were kept under refrigeration at 6°C for 15, 30 and 45 days. For cryopreservation in liquid nitrogen, use of a sucrose-phosphate-glutamate freezing buffer (SPG) as cryoprotectant was compared with dimethylsulfoxide (DMSO) supplemented with sucrose. Cell viability was determined by the trypan blue exclusion test and cell morphology was evaluated in Giemsa-stained cytocentrifuge smears. Results Cold storage at 6°C for up to 30 days was successful in preserving R. (B.) microplus, R. (B.) decoloratus, I. ricinus and I. scapularis cell lines; lines from the latter three species could be easily re-cultivated after 45 days under refrigeration. While cell lines from all four tick species cryopreserved with 6% DMSO were successfully resuscitated, the R. (B.) decoloratus cells did not survive freezing in SPG and of the other three species, only the R. (B.) microplus cells resumed growth during the observation period. Conclusions This constitutes the first report on successful short-term refrigeration of cells derived from R. (B.) decoloratus, R. (B.) microplus, and I. ricinus, and use of SPG as an alternative to DMSO for cryopreservation, thus making an important contribution to more reliable and convenient tick cell culture maintenance.
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Affiliation(s)
- Gertrud Lallinger
- Lehrstuhl für Vergleichende Tropenmedizin und Parasitologie, Ludwig-Maximilians-Universitaet Muenchen, Leopoldstr, 5, 80802, Munich, Germany.
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Wide dispersal and possible multiple origins of low-copy-number plasmids in rickettsia species associated with blood-feeding arthropods. Appl Environ Microbiol 2010; 76:1718-31. [PMID: 20097813 DOI: 10.1128/aem.02988-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Plasmids are mobile genetic elements of bacteria that can impart important adaptive traits, such as increased virulence or antibiotic resistance. We report the existence of plasmids in Rickettsia (Rickettsiales; Rickettsiaceae) species, including Rickettsia akari, "Candidatus Rickettsia amblyommii," R. bellii, R. rhipicephali, and REIS, the rickettsial endosymbiont of Ixodes scapularis. All of the rickettsiae were isolated from humans or North and South American ticks. R. parkeri isolates from both continents did not possess plasmids. We have now demonstrated plasmids in nearly all Rickettsia species that we have surveyed from three continents, which represent three of the four major proposed phylogenetic groups associated with blood-feeding arthropods. Gel-based evidence consistent with the existence of multiple plasmids in some species was confirmed by cloning plasmids with very different sequences from each of two "Ca. Rickettsia amblyommii" isolates. Phylogenetic analysis of rickettsial ParA plasmid partitioning proteins indicated multiple parA gene origins and plasmid incompatibility groups, consistent with possible multiple plasmid origins. Phylogenetic analysis of potentially host-adaptive rickettsial small heat shock proteins showed that hsp2 genes were plasmid specific and that hsp1 genes, found only on plasmids of "Ca. Rickettsia amblyommii," R. felis, R. monacensis, and R. peacockii, were probably acquired independently of the hsp2 genes. Plasmid copy numbers in seven Rickettsia species ranged from 2.4 to 9.2 per chromosomal equivalent, as determined by real-time quantitative PCR. Plasmids may be of significance in rickettsial evolution and epidemiology by conferring genetic plasticity and host-adaptive traits via horizontal gene transfer that counteracts the reductive genome evolution typical of obligate intracellular bacteria.
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Bell-Sakyi L, Růzek D, Gould EA. Cell lines from the soft tick Ornithodoros moubata. EXPERIMENTAL & APPLIED ACAROLOGY 2009; 49:209-19. [PMID: 19252822 PMCID: PMC2755799 DOI: 10.1007/s10493-009-9258-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 02/15/2009] [Indexed: 05/18/2023]
Abstract
Primary cell cultures (n = 16) were initiated from tissues of embryonic and neonatal larval Ornithodoros moubata following methods developed for hard ticks. After maintenance for 20-25 months in vitro, cell multiplication commenced in surviving cultures, leading to the establishment of six cell lines designated OME/CTVM21, 22, 24, 25, 26 and 27. All lines are maintained at 28 degrees C, with subculture at 2-8 week intervals. The cultures comprise heterogeneous populations of large cells of 15-100 microm in diameter, often with finger-like protrusions and/or intracellular crystals, rarely attached, predominantly floating and forming clumps or hollow multicellular vesicles up to 1 mm in diameter. Attempts to cryopreserve the cells are described. Tick-borne encephalitis virus has been serially passaged ten times in OME/CTVM21 cells without significant decrease in virus production and with no change in its biological properties as shown by the size and morphology of plaques produced in porcine kidney cells.
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Affiliation(s)
- Lesley Bell-Sakyi
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK.
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Abstract
The recent discoveries of the pRF and pRM plasmids of Rickettsia felis and R. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus Rickettsia (Rickettsiales; Rickettsiaceae). We report the existence of plasmids in R. helvetica, R. peacockii, R. amblyommii, and R. massiliae isolates from ixodid ticks and in an R. hoogstraalii isolate from an argasid tick. R. peacockii and four isolates of R. amblyommii from widely separated geographic locations contained plasmids that comigrated with pRM during pulsed-field gel electrophoresis and larger plasmids with mobilities similar to that of pRF. The R. peacockii plasmids were lost during long-term serial passage in cultured cells. R. montanensis did not contain a plasmid. Southern blots showed that sequences similar to those of a DnaA-like replication initiator protein, a small heat shock protein 2, and the Sca12 cell surface antigen genes on pRM and pRF were present on all of the plasmids except for that of R. massiliae, which lacked the heat shock gene and was the smallest of the plasmids. The R. hoogstraalii plasmid was most similar to pRM and contained apparent homologs of proline/betaine transporter and SpoT stringent response genes on pRM and pRF that were absent from the other plasmids. The R. hoogstraalii, R. helvetica, and R. amblyommii plasmids contained homologs of a pRM-carried gene similar to a Nitrobacter sp. helicase RecD/TraA gene, but none of the plasmids hybridized with a probe derived from a pRM-encoded gene similar to a Burkholderia sp. transposon resolvase gene.
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