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Hrazdilová K, Myśliwy I, Hildebrand J, Buńkowska-Gawlik K, Janaczyk B, Perec-Matysiak A, Modrý D. Paralogs vs. genotypes? Variability of Babesia canis assessed by 18S rDNA and two mitochondrial markers. Vet Parasitol 2019; 266:103-110. [PMID: 30736942 DOI: 10.1016/j.vetpar.2018.12.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 11/30/2022]
Abstract
Canine babesiosis caused by Babesia canis sensu stricto became an emerging disease of dogs across Europe calling for attention also in countries where it was an only rare imported disease. An easy accessibility of molecular methods and the growing amount of sequencing data led to the description of intraspecific variability in 18S rDNA sequences designated as "genotypes". Using material from a homogenous cohort of dogs with microscopically confirmed canine babesiosis caused by B. canis, we evaluated Babesia intraspecific variability and amplification sensitivity of three different genes (18S rDNA, COI, Cytb) to assess their potential as diagnostic or phylogenetic markers. In raw sequencing data obtained, we observed at least 3 ambiguous positions in up to 86% of chromatograms within the ∼560 bp fragment of 18S rDNA suggesting the existence of several, not identical copies of this gene. Our COI haplotype analysis resulted in a star-like pattern indicating a recent origin of most haplotypes, but not supporting the existence of two dominant haplotypes. Similarly, the Cytb sequences obtained from samples with all variants of 18S rDNA were identical. We corroborate previous observations from three other European countries and bring the evidence of the existence of 18S rDNA paralogs in B. canis genome replacing currently used "genotype" theory.
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Affiliation(s)
- Kristýna Hrazdilová
- CEITEC-VFU, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Department of Virology, Veterinary Research Institute, Hudcova 296/70, 621 00, Brno, Czech Republic.
| | - Izabella Myśliwy
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63, 51-148, Wrocław, Poland
| | - Joanna Hildebrand
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63, 51-148, Wrocław, Poland
| | - Katarzyna Buńkowska-Gawlik
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63, 51-148, Wrocław, Poland
| | - Bartłomiej Janaczyk
- Vetlab, Veterinary Diagnostic Laboratory, Parkowa 13, 51-616, Wrocław, Poland
| | - Agnieszka Perec-Matysiak
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63, 51-148, Wrocław, Poland
| | - David Modrý
- CEITEC-VFU, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Department of Pathological Morphology and Parasitology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého tř. 1946/1, 612 42, Brno, Czech Republic; Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
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Rapid and sensitive detection of Babesia bovis and Babesia bigemina by loop-mediated isothermal amplification combined with a lateral flow dipstick. Vet Parasitol 2016; 219:71-6. [DOI: 10.1016/j.vetpar.2016.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 11/20/2022]
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3
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Saito-Ito A, Kasahara M, Kasai M, Dantrakool A, Kawai A, Fujita H, Yano Y, Kawabata H, Takada N. Survey ofBabesia microtiInfection in Field Rodents in Japan: Records of the Kobe-Type in New Foci and Findings of a New Type Related to the Otsu-Type. Microbiol Immunol 2013; 51:15-24. [PMID: 17237595 DOI: 10.1111/j.1348-0421.2007.tb03886.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Of 247 rodents comprising 5 genera and 7 species collected at 17 sites throughout Japan from 2003 to 2005, Babesia microti was detected microscopically and by polymerase chain reaction (PCR) in 36 rodents comprising 2 genera and 3 species from 12 sites. Based on the analysis of small subunit ribosomal RNA gene (SSUrDNA) sequences, the Kobe-type, the etiological type of the first Japanese case of human infection was found in Apodemus speciosus and Apodemus argenteus in Aomori, the northernmost prefecture of the Japanese mainland, while the U.S.-type was found on Hokkaido Island and the Otsu-type was widely distributed. In addition, a new Otsu-related type was detected exclusively in Eothenomys andersoni in Nagano, a prefecture in central Japan. The sequences of internal transcribed spacer 1 to 2 (ITS1/2) of the present Kobe- and Otsu-types were almost identical to those of the same types previously identified. The ITS1/2 sequence of the U.S.-type identified in Hokkaido in this survey was somewhat different from that of the U.S.-type strain originating from the U.S.A., with approximately 95% identity. This value was similar to the 94% identity found between the ITS1/2 sequences of the Otsu-type and the new Otsu-related type. The new Otsu-related type of B. microti was isolated as the Nagano strain, which was serologically differentiated from the other type strains of B. microti. The divergence and distribution of genotypes are important factors in investigating the epidemiology of human B. microti infection in Japan.
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MESH Headings
- Animals
- Babesia microti/classification
- Babesia microti/genetics
- Babesia microti/isolation & purification
- Babesiosis/epidemiology
- Babesiosis/parasitology
- Babesiosis/veterinary
- Cricetinae
- DNA, Intergenic/analysis
- DNA, Intergenic/chemistry
- DNA, Intergenic/genetics
- DNA, Protozoan/analysis
- DNA, Protozoan/chemistry
- DNA, Protozoan/genetics
- DNA, Ribosomal/analysis
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Japan/epidemiology
- Molecular Epidemiology
- Molecular Sequence Data
- Phylogeny
- Polymerase Chain Reaction
- Rodent Diseases/epidemiology
- Rodent Diseases/parasitology
- Rodentia
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Atsuko Saito-Ito
- Section of Parasitology, Division of Microbiology, Kobe University Graduate School of Medicine, Japan.
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4
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Torres-Machorro AL, Hernández R, Cevallos AM, López-Villaseñor I. Ribosomal RNA genes in eukaryotic microorganisms: witnesses of phylogeny? FEMS Microbiol Rev 2010; 34:59-86. [DOI: 10.1111/j.1574-6976.2009.00196.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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5
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Using msa-2b as a molecular marker for genotyping Mexican isolates of Babesia bovis. INFECTION GENETICS AND EVOLUTION 2009; 9:1102-7. [DOI: 10.1016/j.meegid.2009.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 03/21/2009] [Accepted: 03/26/2009] [Indexed: 11/22/2022]
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6
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Brown HM, Modaresi SM, Cook JL, Latimer KS, Peterson DS. Genetic variability of archived Cytauxzoon felis histologic specimens from domestic cats in Georgia, 1995-2007. J Vet Diagn Invest 2009; 21:493-8. [PMID: 19564497 DOI: 10.1177/104063870902100410] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Cytauxzoon felis infection in domestic cats has historically been nearly 100% fatal. However, increasing reports of domestic cats that survive cytauxzoonosis and reports of asymptomatic cats with C. felis infections suggest the existence of different parasite strains that vary in pathogenicity. The objective of the current study was to obtain epidemiologic information about cytauxzoonosis through genotypic characterization of archived histologic specimens from domestic cats with C. felis infections that were diagnosed in Georgia between 1995 and 2007. Such retrospective data on genetic variability will provide an historic context for current studies of C. felis genotype frequencies. Cytauxzoon felis DNA was obtained from formalin-fixed, paraffin-embedded tissues from infected cats diagnosed with cytauxzoonosis at necropsy. Genetic characterization of C. felis was performed using sequence analysis of the polymerase chain reaction-amplified ribosomal internal transcribed spacer regions 1 and 2 (ITS1, ITS2). Eleven different combined ITS1 and ITS2 sequences were identified, the majority of which were identical to those previously reported in fatally infected cats from Georgia. The findings of the current study document the existence of genetically distinct C. felis populations in historical samples and, together with data from contemporary samples, demonstrate a diverse population structure for C. felis.
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Affiliation(s)
- Holly M Brown
- Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA.
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7
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Laughery JM, Lau AO, White SN, Howell JM, Suarez CE. Babesia bovis: Transcriptional analysis of rRNA gene unit expression. Exp Parasitol 2009; 123:45-50. [DOI: 10.1016/j.exppara.2009.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 05/15/2009] [Accepted: 05/26/2009] [Indexed: 11/25/2022]
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8
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Takabatake N, Iseki H, Ikehara Y, Kanuka H, Yokoyama N, Sekimizu K, Igarashi I. Isolation and pathogenic characterization of an OB1 variant of Babesia rodhaini which has a glycophorin A-independent pathway to murine red blood cells. Vet Parasitol 2009; 159:97-104. [DOI: 10.1016/j.vetpar.2008.10.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 09/15/2008] [Accepted: 10/07/2008] [Indexed: 11/16/2022]
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9
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Genis AD, Mosqueda JJ, Borgonio VM, Falcón A, Alvarez A, Camacho M, de Lourdes Muñoz M, Figueroa JV. Phylogenetic analysis of Mexican Babesia bovis isolates using msa and ssrRNA gene sequences. Ann N Y Acad Sci 2009; 1149:121-5. [PMID: 19120189 DOI: 10.1196/annals.1428.070] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Variable merozoite surface antigens of Babesia bovis are exposed glycoproteins having a role in erythrocyte invasion. Members of this gene family include msa-1 and msa-2 (msa-2c, msa-2a(1), msa-2a(2), and msa-2b). Small subunit ribosomal (ssr)RNA gene is subject to evolutive pressure and has been used in phylogenetic studies. To determine the phylogenetic relationship among B. bovis Mexican isolates using different genetic markers, PCR amplicons, corresponding to msa-1, msa-2c, msa-2b, and ssrRNA genes, were cloned and plasmids carrying the corresponding inserts were sequenced. Comparative analysis of nucleotide and deduced amino acid sequences revealed distinct degrees of variability and identity among the coding gene sequences obtained from 12 geographically different B. bovis isolates and a reference strain. Overall sequence identities of 47.7%, 72.3%, 87.7%, and 94% were determined for msa-1, msa-2b, msa-2c, and ssrRNA, respectively. A robust phylogenetic tree was obtained with msa-2b sequences. The phylogenetic analysis suggests that Mexican B. bovis isolates group in clades not concordant with the Mexican geography. However, the Mexican isolates group together in an American clade separated from the Australian clade. Sequence heterogeneity in msa-1, msa-2b, and msa-2c coding regions of Mexican B. bovis isolates present in different geographical regions can be a result of either differential evolutive pressure or cattle movement from commercial trade.
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Affiliation(s)
- Alma D Genis
- Posgrado en Ciencias Genomicas, Universidad Autonoma de la Ciudad de Mexico, México City, México
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10
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Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa. Vet Parasitol 2008; 159:112-20. [PMID: 19019541 DOI: 10.1016/j.vetpar.2008.10.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 09/19/2008] [Accepted: 10/03/2008] [Indexed: 11/21/2022]
Abstract
A molecular epidemiological survey of the protozoal parasites that cause equine piroplasmosis was conducted using samples collected from horses and zebra from different geographical locations in South Africa. A total of 488 samples were tested for the presence of Theileria equi and/or Babesia caballi using the reverse line blot hybridization assay. Ten percent of the samples hybridized to the Theileria/Babesia genus-specific probe and not to the B. caballi or T. equi species-specific probes, suggesting the presence of a novel species or genotype. The small subunit of rRNA gene (18S; approximately 1600bp) was amplified and sequenced from 33 of these 488 samples. Sequences were compared with published sequences from the public sequence databases. Twelve distinct T. equi and six B. caballi 18S rRNA sequences were identified. Alignments demonstrated extensive sequence variation in the V4 hypervariable region of the 18S rRNA gene within T. equi. Sequence variation was also found in B. caballi 18S rRNA genes, although there was less variation than observed for T. equi. Phylogenetic analysis based on 18S rRNA gene sequences revealed three T. equi clades and two B. caballi clades in South Africa. The extent of sequence heterogeneity detected within T. equi and B. caballi 18S rRNA genes was unexpected since concerted evolution is thought to maintain homogeneity within repeated gene families, including rRNA genes, in eukaryotes. The findings reported here show that careful examination of variants of the 18S rRNA gene of T. equi and B. caballi is required prior to the development of molecular diagnostic tests to detect these parasites in horses. Species-specific probes must be in designed in regions of the gene that are both conserved within and unique to each species.
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11
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Loram JE, Boonham N, O'Toole P, Trapido-Rosenthal HG, Douglas AE. Molecular quantification of symbiotic dinoflagellate algae of the genus Symbiodinium. THE BIOLOGICAL BULLETIN 2007; 212:259-68. [PMID: 17565115 DOI: 10.2307/25066608] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The dinoflagellate microalga Symbiodinium is the dominant algal symbiont in corals and related marine animals. To explore the incidence of mixed infections, methods employing real-time quantitative polymerase chain reaction (QPCR) and fluorescence in situ hybridization (FISH) were developed. In experiments focusing on Symbiodinium clades A and B, QPCR and FISH results were well correlated and generally more precise and sensitive than those from the endpoint PCR-restriction fragment length polymorphism analysis (PCR-RFLP) traditionally used for this application, thus increasing the detected incidence of mixed infections. For example, the prevalence of mixed infections in the sea anemone Condylactis gigantea was 40% by PCR-RFLP and 80%-90% by QPCR and FISH. However, the use of QPCR and FISH was limited by inter-host variation in the rRNA gene copy number per Symbiodinium cell, precluding any single conversion factor between QPCR signal and Symbiodinium cell number; and one FISH probe that gave excellent hybridization efficiency with cultured Symbiodinium yielded variable results with Symbiodinium from symbioses. After controlling for these caveats, QPCR studies revealed that field-collected hosts previously described as universally unialgal bore up to 1.6% of the alternative clade. Further research is required to establish the contribution that algal cells at low density in symbiosis and external to the symbiosis make to the minor clade.
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12
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Guerrero FD, Bendele KG, Davey RB, George JE. Detection of Babesia bigemina infection in strains of Rhipicephalus (Boophilus) microplus collected from outbreaks in South Texas. Vet Parasitol 2007; 145:156-63. [PMID: 17178440 DOI: 10.1016/j.vetpar.2006.11.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 11/15/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
The sudden death of several cattle infested experimentally with Rhipicephalus (Boophilus) microplus led to a clinical investigation into the reasons for the unexpected mortality. Microscopic evidence for Babesia bigemina infection was found in blood smears from the affected animals and a PCR assay was designed to detect the presence of B. bigemina and Babesia bovis in all R. microplus strains received and propagated at the laboratory. The assay utilizes a nested PCR approach with the first PCR amplifying a well-conserved segment from the Babesia 18S ribosomal RNA gene followed by a nested PCR with Babesia species-specific primers and annealing temperatures enabling amplification of the 18S ribosomal RNA gene fragment specific to either B. bigemina or B. bovis. DNA from groups of 50 larvae was extracted using a rapid DNA preparation protocol, which consisted of grinding the frozen tick larvae in PCR buffer and boiling the mixture for 5min. The assay sensitivity allowed for the detection of the equivalent of a single infected tick larva. R. microplus eggs were also analyzed, but yolk protein viscosity created inconsistent results with the crush and boil DNA isolation protocol, necessitating the use of a more extensive proteinase K digestion-based DNA purification method. We detected the presence of B. bigemina in all strains of R. microplus currently reared at the laboratory and 4 of 26 strains collected from infestation outbreaks in Texas by the U.S. Cattle Fever Tick Eradication Program.
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Affiliation(s)
- F D Guerrero
- USDA-ARS Knipling-Bushland, US Livestock Insects Research Laboratory, Kerrville, TX 78028, USA.
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13
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Jefferies R, Ryan UM, Irwin PJ. PCR-RFLP for the detection and differentiation of the canine piroplasm species and its use with filter paper-based technologies. Vet Parasitol 2006; 144:20-7. [PMID: 17127005 DOI: 10.1016/j.vetpar.2006.09.022] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Revised: 09/12/2006] [Accepted: 09/13/2006] [Indexed: 10/23/2022]
Abstract
Canine piroplasmosis is an emerging disease worldwide, with multiple species of piroplasm now recognised to infect dogs. A nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was developed for the detection and differentiation of each of the piroplasm species currently known to infect dogs on the basis of the 18S ribosomal RNA gene. The assay can potentially amplify and discriminate between Theileria annae, Theileria equi, Babesia conradae, Babesia gibsoni, Babesia sp. (Coco) and each of the Babesia canis subspecies. Non-canine piroplasm species can also potentially be detected using the described assay, however amplification of Neospora caninum was also observed. The PCR was found to have a high detection limit, capable of detecting a 2.7x10(-7)% parasitaemia or the equivalent of 1.2 molecules of target DNA when using DNA extracted from whole EDTA blood and detected a parasitaemia of 2.7x10(-5)% using blood applied to both Flinders Technology Associates (FTA) cards and IsoCodetrade mark Stix. The application of blood samples to filter paper may greatly assist in piroplasm identification in regions of the world where local technologies for molecular characterisation are limited. The assay reported here has the potential to be standardised for routine screening of dogs for piroplasmosis.
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Affiliation(s)
- R Jefferies
- Australasian Centre for Companion Animal Research, Division of Health Sciences, Murdoch University, WA 6150, Australia
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14
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Goethert HK, Cook JA, Lance EW, Telford SR. Fay and Rausch 1969 revisited: Babesia microti in Alaskan small mammals. J Parasitol 2006; 92:826-31. [PMID: 16995402 DOI: 10.1645/ge-584r.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The Holarctic distribution of Babesia microti within small rodents implies an ancient association. A seminal report of piroplasms in Alaskan voles suggested to us the possibility that B. microti entered North America within Eurasian microtine rodents dispersing through Beringian corridors. To test this hypothesis, we analyzed samples from Alaskan rodents by polymerase chain reaction for evidence of infection with B. microti; one-third of the rodents were found to be infected. Sequence analysis of the 18S rDNA gene demonstrates that Alaskan B. microti comprises a clade that infects microtines in several sites across North America and is distinct from a clade that is zoonotic.
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Affiliation(s)
- Heidi K Goethert
- Division of Infectious Diseases, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA
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15
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Criado A, Martinez J, Buling A, Barba JC, Merino S, Jefferies R, Irwin PJ. New data on epizootiology and genetics of piroplasms based on sequences of small ribosomal subunit and cytochrome b genes. Vet Parasitol 2006; 142:238-47. [PMID: 16919391 DOI: 10.1016/j.vetpar.2006.07.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 06/15/2006] [Accepted: 07/06/2006] [Indexed: 11/20/2022]
Abstract
As a continuation of our studies on molecular epizootiology of piroplasmosis in Spain and other countries, we present in this contribution the finding of new hosts for some piroplasms, as well as information on their 18S rRNA gene sequences. Genetic data were complemented with sequences of apocytochrome b gene (whenever possible). The following conclusions were drawn from these molecular studies: Theileria annulata is capable of infecting dogs, since it was diagnosed in a symptomatic animal. According to cytochrome b sequences, isolates from cows and dog present slight differences. The same isolates showed, however, identical sequence in the 18S rRNA gene. This exemplifies well the usefulness of the mitochondrial gene for examining infra-specific variation. Babesia bovis is an occasional parasite of equines, since it was detected in two symptomatic horses. We found evidence of genetic polymorphism occurring in the 18S rRNA gene of Spanish T. equi-like and B. ovis isolates. B. bennetti from Spanish seagull is loosely related to B. ovis, and might represent a genetically distinct branch of babesids. A partial sequence of a cytochrome b pseudogene was obtained for the first time in Babesia canis rossi from South Africa. The pseudogene is distantly related to B. bigemina cytochrome b gene. These new findings confirm the ability of some piroplasms to infect multiple hosts, as well as the existence of a relatively wide genetic polymorphisms with respect to the cytochrome b gene. On the other hand, the existence of mtDNA-like pseudogenes of possible nuclear location in piroplasms is interesting due to their possible impact on molecular phylogeny studies.
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Affiliation(s)
- A Criado
- Microbiology and Parasitology Department, Faculty of Pharmacy, University of Alcalá, 28871 Alcalá de Henares, Spain.
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Bondy PJ, Cohn LA, Tyler JW, Marsh AE. Polymerase Chain Reaction Detection of Cytauxzoon felis From Field-Collected Ticks and Sequence Analysis of the Small Subunit and Internal Transcribed Spacer 1 Region of the Ribosomal RNA Gene. J Parasitol 2005; 91:458-61. [PMID: 15986625 DOI: 10.1645/ge-374r] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cytauxzoon felis produces a disease in domestic cats in the Midwest (U.S.A.), which often leads to a fatal outcome. Although the clinical disease process is well described, there are still many unanswered questions about this organism. For example, it is unknown whether species of ticks other than Dermacentor variabilis can serve as vectors for transmission. With recent reports of surviving cats from limited geographic areas, another relevant question is the potential for genetically less virulent organism strains. This study evaluated 352 individual or pooled tick samples (1,362 total ticks) for the presence of C. felis small subunit ribosomal RNA and internal transcribed spacer 1 (ITS-1) region genes using a polymerase chain reaction (PCR). These ticks were collected from dogs and cats in several Missouri counties, including 10 from cats diagnosed with cytauxzoonosis. Only 3 positive C. felis samples were identified in Amblyomma americanum nymphs, and there was very limited genetic variation noted in both genes. The small number of positive samples did not allow the study to determine which PCR analysis was more sensitive. This is the first known report of ITS-1 gene identification and sequencing for C. felis. It is also the first published investigation of genetic variation in C. felis.
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Affiliation(s)
- P J Bondy
- Department of Veterinary Medicine and Surgery, College of Veterinary Medcine, University of Missouri, Columbia, Missouri 65211, USA
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Morrison DA. Networks in phylogenetic analysis: new tools for population biology. Int J Parasitol 2005; 35:567-82. [PMID: 15826648 DOI: 10.1016/j.ijpara.2005.02.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Revised: 02/10/2005] [Accepted: 02/10/2005] [Indexed: 11/29/2022]
Abstract
Phylogenetic analysis has changed greatly in the past decade, including the more widespread appreciation of the idea that evolutionary histories are not always tree-like, and may, thus, be best represented as reticulated networks rather than as strictly dichotomous trees. Reconstructing such histories in the absence of a bifurcating speciation process is even more difficult than the usual procedure, and a range of alternative strategies have been developed. There seem to be two basic uses for a network model of evolution: the display of real but unobservable evolutionary events (i.e. a hypothesis of the true phylogenetic history), and the display of character conflict within the data itself (i.e. a summary of the data). These two general approaches are briefly reviewed here, and the strengths and weaknesses of the different implementations are compared and contrasted. Each network methodology seems to have limitations in terms of how it responds to increasing complexity (e.g. conflict) in the data, and therefore each is likely to be more appropriate for one of the two uses than for the other. Several examples using parasitological data sets illustrate the uses of networks within the context of population biology.
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Affiliation(s)
- David A Morrison
- Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, 751 89 Uppsala, Sweden.
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Pecher WT, Robledo JAF, Vasta GR. Identification of a second rRNA gene unit in the Perkinsus andrewsi genome. J Eukaryot Microbiol 2004; 51:234-45. [PMID: 15134261 DOI: 10.1111/j.1550-7408.2004.tb00553.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Perkinsus species are parasitic protozoa of mollusks, currently classified within the Perkinsozoa, a recently established phylum that is basal to the Apicomplexa and Dinozoa. Ribosomal RNA (rRNA) genes and their intergenic spacers have been used to support the taxonomy of Perkinsus species, the description of new species, and to develop molecular probes for their detection and identification. We previously described ultrastructure, behavior in culture, and partial sequence of the rRNA locus of a Perkinsus species isolated from the baltic clam Macoma balthica. The rRNA genes and intergenic spacers of this Perkinsus isolate differed from those described in the currently accepted species to a degree that led to its designation as a new species, Perkinsus andrewsi. In this study, we identify an additional rRNA gene unit (rRNA-B) in the P. andrewsi holotype, and report the complete sequences of both rRNA gene units. Except for the 5.8S, all regions of the rRNA-B gene unit exhibited sequence differences from that initially described (rRNA-A). Each rRNA gene unit is arranged in a "head-to-tail" tandem repeat. This is the first report demonstrating two distinct rRNA units in a Perkinsus species.
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MESH Headings
- Animals
- Base Sequence
- DNA, Intergenic/genetics
- DNA, Protozoan/chemistry
- DNA, Protozoan/isolation & purification
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/genetics
- Eukaryota/genetics
- Gene Order
- Genes, rRNA
- Genome
- Genome, Protozoan
- Molecular Sequence Data
- Mollusca/parasitology
- RNA, Ribosomal, 5.8S/genetics
- RNA, Ribosomal, 5S/genetics
- Restriction Mapping
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- rRNA Operon
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Affiliation(s)
- Wolf T Pecher
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, University of Maryland, Baltimore, Maryland 21202, USA
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19
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Galluzzi L, Penna A, Bertozzini E, Vila M, Garcés E, Magnani M. Development of a real-time PCR assay for rapid detection and quantification of Alexandrium minutum (a Dinoflagellate). Appl Environ Microbiol 2004; 70:1199-206. [PMID: 14766606 PMCID: PMC348872 DOI: 10.1128/aem.70.2.1199-1206.2004] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The marine dinoflagellate genus Alexandrium includes a number of species which produce neurotoxins responsible for paralytic shellfish poisoning (PSP), which in humans may cause muscular paralysis, neurological symptoms, and, in extreme cases, death. A. minutum is the most widespread toxic PSP species in the western Mediterranean basin. The monitoring of coastal waters for the presence of harmful algae also normally involves microscopic examinations of phytoplankton populations. These procedures are time consuming and require a great deal of taxonomic experience, thus limiting the number of specimens that can be analyzed. Because of the genetic diversity of different genera and species, molecular tools may also help to detect the presence of target microorganisms in marine field samples. In this study, we developed a real-time PCR-based assay for rapid detection of all toxic species of the Alexandrium genus in both fixative-preserved environmental samples and cultures. Moreover, we developed a real-time quantitative PCR assay for the quantification of A. minutum cells in seawater samples. Alexandrium genus-specific primers were designed on the 5.8S rDNA region. Primer specificity was confirmed by using BLAST and by amplification of a representative sample of the DNA of other dinoflagellates and diatoms. Using a standard curve constructed with a plasmid containing the ITS1-5.8S-ITS2 A. minutum sequence and cultured A. minutum cells, we determined the absolute number of 5.8S rDNA copies per cell. Consequently, after quantification of 5.8S rDNA copies in samples containing A. minutum cells, we were also able to estimate the number of cells. Several fixed A. minutum bloom sea samples from Arenys Harbor (Catalan Coast, Spain) were analyzed using this method, and quantification results were compared with standard microscopy counting methods. The two methods gave comparable results, confirming that real-time PCR could be a valid, fast alternative procedure for the detection and quantification of target phytoplankton species during coastal water monitoring.
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Affiliation(s)
- Luca Galluzzi
- Center of Biotechnology, University of Urbino, 61032 Fano (PU), Italy
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20
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Abstract
Babesia microti (Apicomplexa: Piroplasmida) has historically been considered a common parasite of Holarctic rodents. However, human babesiosis due to this species has generally been limited to the northeastern seaboard of the United States and Minnesota and Wisconsin. The absence of reports of B. microti babesiosis from sites where the agent is enzootic, such as in western Europe, remains unexplained. Previous work focusing on the 18S rDNA demonstrates little sequence diversity among samples from allopatric host populations across a wide geographical area. It may be that genetic diversity is underestimated due to sample size or the gene analysed. Accordingly, we collected blood or spleen samples from American or Eurasian animals with parasites that were morphologically consistent with B. microti, amplified the 18S rDNA and beta-tubulin gene, and conducted phylogenetic analysis. Surprisingly, what was considered to be 'B. microti' by microscopy appears to be a diverse species complex. We identify 3 distinct clades within this complex, including parasites from non-rodent hosts. Rodent parasites comprise 2 clades, one representing zoonotic isolates, and the other apparently maintained in microtine rodents, and therefore their morphological detection within animals from a site does not necessarily imply a risk to public health.
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Affiliation(s)
- H K Goethert
- Department of Immunology and Infectious Diseases, 665 Huntington Avenue, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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21
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Saito K, Drgon T, Robledo JAF, Krupatkina DN, Vasta GR. Characterization of the rRNA locus of Pfiesteria piscicida and development of standard and quantitative PCR-based detection assays targeted to the nontranscribed spacer. Appl Environ Microbiol 2002; 68:5394-407. [PMID: 12406730 PMCID: PMC129931 DOI: 10.1128/aem.68.11.5394-5407.2002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pfiesteria piscicida is a heterotrophic dinoflagellate widely distributed along the middle Atlantic shore of the United States and associated with fish kills in the Neuse River (North Carolina) and the Chesapeake Bay (Maryland and Virginia). We constructed a genomic DNA library from clonally cultured P. piscicida and characterized the nontranscribed spacer (NTS), small subunit, internal transcribed spacer 1 (ITS1), 5.8S region, ITS2, and large subunit of the rRNA gene cluster. Based on the P. piscicida ribosomal DNA sequence, we developed a PCR-based detection assay that targets the NTS. The assay specificity was assessed by testing clonal P. piscicida and Pfiesteria shumwayae, 35 additional dinoflagellate species, and algal prey (Rhodomonas sp.). Only P. piscicida and nine presumptive P. piscicida isolates tested positive. All PCR-positive products yielded identical sequences for P. piscicida, suggesting that the PCR-based assay is species specific. The assay can detect a single P. piscicida zoospore in 1 ml of water, 10 resting cysts in 1 g of sediment, or 10 fg of P. piscicida DNA in 1 micro g of heterologous DNA. An internal standard for the PCR assay was constructed to identify potential false-negative results in testing of environmental sediment and water samples and as a competitor for the development of a quantitative competitive PCR assay format. The specificities of both qualitative and quantitative PCR assay formats were validated with >200 environmental samples, and the assays provide simple, rapid, and accurate methods for the assessment of P. piscicida in water and sediments.
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Affiliation(s)
- Keiko Saito
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA
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22
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Mercereau-Puijalon O, Barale JC, Bischoff E. Three multigene families in Plasmodium parasites: facts and questions. Int J Parasitol 2002; 32:1323-44. [PMID: 12350369 DOI: 10.1016/s0020-7519(02)00111-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Multigene families optimise fitness by providing a set of related genes with possibly different temporal and/or topological expression patterns. We analyse here the structural organisation and sequence diversity of the rDNA, sera and var C Plasmodium falciparum families, and discuss their consequences for parasite biology. The low rDNA copy number, which reduces reshuffling, is probably the corollary of the need for functionally distinct rRNAs in the insect and in the vertebrate host. The unusual intra-genome and population rDNA sequence diversity results in cells equipped with mosaic ribosome sets. The functional constraints are such that ribosome compatibility could influence parasite fitness and contribute to population structuring. Unlike the dispersed rDNA units, the sera family is arranged as a tandem gene cluster, with seven contiguous similar genes, and one more distantly related paralog. We address the question of the inclusion criteria in family definition. We discuss the results concerning the SERA proteins expression and function in the context of the long overlooked multigene family. The var C module is shared by var genes, 'orphan' var C and var C pseudogenes. Analysis of 125 var C deduced protein sequences highlights a well-conserved framework, including putative phosphorylation sites, consistent with the proposed function of mediating interaction with cytoskeletal proteins. The 5' and 3' flanking sequences of the var C pseudogenes are heterogeneous. In contrast, the flanking sequences of the uninterrupted var C modules show remarkable conservation. This is interesting in view of the silencing activity of the var intronic sequence on var expression. The 5' flanking sequence dichotomy reported for internal and sub-telomeric var genes extends to the 3' flanking sequences. This has profound implications for transcription regulation and generation of diversity. The var C family suggests a role for pseudogenes as a diversity reservoir and in genome dynamics by promoting ectopic recombination.
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Affiliation(s)
- Odile Mercereau-Puijalon
- Unité d'Immunologie Moléculaire des Parasites, Unité de Recherche Associée 1960 du Centre National de la Recherche Scientifique, Institut Pasteur, 25 rue du Dr ROUX, 75015, Paris, France.
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23
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Collins NE, Allsopp MTEP, Allsopp BA. Molecular diagnosis of theileriosis and heartwater in bovines in Africa. Trans R Soc Trop Med Hyg 2002; 96 Suppl 1:S217-24. [PMID: 12055842 DOI: 10.1016/s0035-9203(02)90079-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The advent of the polymerase chain reaction (PCR) coupled with the specificity of deoxyribocucleic acid (DNA)-DNA hybridization has led to the development of specific and sensitive molecular diagnostic tests to detect and characterize the organisms that cause theileriosis and heartwater. Theileriosis is a widespread disease of wild and domestic ruminants caused by apicomplexan parasites of the genus Theileria. Species-specific variations in small subunit ribosomal ribonucleic acid genes (SSUrRNA) have been used to develop probes that can distinguish between Theileria species such as T. parva, T. annulata, T. mutans, T. buffeli and T. taurotragi. Routine application of this test has led to the discovery of previously unknown species, such as Theileria sp. (buffalo) which is apparently apathogenic to both buffalo and cattle, and Theileria sp. (sable) which is pathogenic to sable and possibly also to roan antelope. In addition, characterization probes located in the internal transcribed spacer (ITS) can be used to distinguish between most isolates of the causative agents of East Coast fever (T. p. parva) and Corridor disease (T. p. lawrencei). Heartwater is an economically important disease of livestock and some wild ruminants, caused by the intracellular rickettsial parasite Ehrlichia (ex Cowdria) ruminantium. DNA probes used to detect and characterize E. ruminantium isolates include SSUrRNA (16S) probes, the pCS20 probe and map1 probes. A panel of eight 16S probes has been developed for the detection of E. ruminantium and related Ehrlichia species. There are probes for 5 different E. ruminantium genotypes, one which will detect all 5 of these genotypes, one to detect any Ehrlichia species other than E. ruminantium, and one for any Anaplasma species. The pCS20 probe is specific for E. ruminantium and is the most sensitive of the probes for E. ruminantium detection, but it is not able to distinguish among the different genotypes. The map1 gene has also been used for diagnosis, but the extensive polymorphism of this gene means that it is most useful for characterization of different genotypes of the parasite. Routine application of these tests has led to the discovery of new genotypes that are probably not E. ruminantium but are probably new species of Ehrlichia.
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Affiliation(s)
- Nicola E Collins
- Onderstepoort Veterinary Institute, Private Bag X5, Ondesterpoort 0110, South Africa
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24
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Olivier C, van de Pas S, Lepp PW, Yoder K, Relman DA. Sequence variability in the first internal transcribed spacer region within and among Cyclospora species is consistent with polyparasitism. Int J Parasitol 2001; 31:1475-87. [PMID: 11595235 DOI: 10.1016/s0020-7519(01)00283-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cyclospora cayetanensis is a coccidian parasite which causes severe gastroenteritis in humans. Molecular information on this newly emerging pathogen is scarce. Our objectives were to assess genetic variation within and between human-associated C. cayetanensis and baboon-associated Cyclospora papionis by examining the internal transcribed spacer (ITS) region of the ribosomal RNA operon, and to develop an efficient polymerase chain reaction- (PCR)-based method to distinguish C. cayetanensis from other closely related organisms. For these purposes, we studied C. cayetanensis ITS-1 nucleotide variability in 24 human faecal samples from five geographic locations and C. papionis ITS-1 variability in four baboon faecal samples from Tanzania. In addition, a continuous sequence encompassing ITS-1, 5.8S rDNA and ITS-2 was determined from two C. cayetanensis samples. The results indicate that C. cayetanensis and C. papionis have distinct ITS-1 sequences, but identical 5.8S rDNA sequences. ITS-1 is highly variable within and between samples, but variability does not correlate with geographic origin of the samples. Despite this variability, conserved species-specific ITS-1 sequences were identified and a single-round, C. cayetanensis-specific PCR-based assay with a sensitivity of one to ten oocysts was developed. This consistent and remarkable diversity among Cyclospora spp. ITS-1 sequences argues for polyparasitism and simultaneous transmission of multiple strains.
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MESH Headings
- Animals
- Base Sequence
- Cyclospora/chemistry
- Cyclospora/classification
- Cyclospora/genetics
- Cyclosporiasis/parasitology
- DNA, Protozoan/chemistry
- DNA, Protozoan/genetics
- DNA, Protozoan/isolation & purification
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/chemistry
- DNA, Ribosomal Spacer/genetics
- Genetic Variation
- Humans
- Molecular Sequence Data
- Phylogeny
- Polymerase Chain Reaction/methods
- RNA, Ribosomal, 5.8S/genetics
- Sequence Homology, Nucleic Acid
- Species Specificity
- rRNA Operon/genetics
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Affiliation(s)
- C Olivier
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
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25
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van Spaendonk RM, Ramesar J, van Wigcheren A, Eling W, Beetsma AL, van Gemert GJ, Hooghof J, Janse CJ, Waters AP. Functional equivalence of structurally distinct ribosomes in the malaria parasite, Plasmodium berghei. J Biol Chem 2001; 276:22638-47. [PMID: 11292830 DOI: 10.1074/jbc.m101234200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Unlike most eukaryotes, many apicomplexan parasites contain only a few unlinked copies of ribosomal RNA (rRNA) genes. Based on stage-specific expression of these genes and structural differences among the rRNA molecules it has been suggested that Plasmodium spp. produce functionally different ribosomes in different developmental stages. This hypothesis was investigated through comparison of the structure of the large subunit rRNA molecules of the rodent malaria parasite, Plasmodium berghei, and by disruption of both of the rRNA gene units that are transcribed exclusively during development of this parasite in the mosquito (S-type rRNA gene units). In contrast to the human parasite, Plasmodium falciparum, we did not find evidence of structural differences in core regions of the distinct large subunit rRNAs which are known to be associated with catalytic activity including the GTPase site that varies in P. falciparum. Knockout P. berghei parasites lacking either of the S-type gene units were able to complete development in both the vertebrate and mosquito hosts. These results formally exclude the hypothesis that two functionally different ribosome types distinct from the predominantly blood stage-expressed A-type ribosomes, are required for development of all Plasmodium species in the mosquito. The maintenance of two functionally equivalent rRNA genes might now be explained as a gene dosage phenomenon.
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Affiliation(s)
- R M van Spaendonk
- Department of Parasitology, Leiden University Medical Centre, Postbus 9600, 2300 RC Leiden, The Netherlands
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26
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Bishop R, Gobright E, Spooner P, Allsopp B, Sohanpal B, Collins N. Microsequence heterogeneity and expression of the LSU rRNA genes within the two single copy ribosomal transcription units of Theileria parva. Gene 2000; 257:299-305. [PMID: 11080596 DOI: 10.1016/s0378-1119(00)00386-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The nucleotide sequences of the large subunit ribosomal RNA coding genes within the two single copy ribosomal DNA transcription units of a cloned Theileria parva isolate from a buffalo were determined. The two LSU rRNA coding units differed by 11 nucleotide substitutions and two deletions of 1 and 6 bp, all located in the 5' end of the LSU coding region. We also observed microsequence heterogeneity between the two buffalo parasite LSU sequences and the previously determined LSU rRNA gene of a T. parva parasite isolated from cattle. At all positions which were variable between the two LSU rRNA coding sequences of the buffalo-derived parasite, either unit 1 or unit 2 matched the LSU rRNA coding sequence of the cattle-derived T. parva parasite in a mosaic pattern. Synthetic oligonucleotides specific for LSU units 1 and 2 of the buffalo T. parva were developed, and used to assay expression of the two units. Both units were expressed in the intra-lymphocytic schizont stage of T. parva. A 2.5-10-fold excess of rRNA derived from LSU unit 1, compared with unit 2, was observed in the schizont stage, the difference being attributable to variation in the level of expression of unit 2. Theileria represents the third genus of Sporozoan protozoa, in addition to Plasmodium and Babesia, exhibiting rRNA coding genes, which are divergent in sequence between different transcription units.
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Affiliation(s)
- R Bishop
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya.
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27
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Adam RD, Ortega YR, Gilman RH, Sterling CR. Intervening transcribed spacer region 1 variability in Cyclospora cayetanensis. J Clin Microbiol 2000; 38:2339-43. [PMID: 10834999 PMCID: PMC86797 DOI: 10.1128/jcm.38.6.2339-2343.2000] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyclospora cayetanensis is an apicomplexan protozoan parasite which has emerged as an important cause of epidemic and endemic diarrhea. Water-borne as well as food-borne outbreaks have occurred, including a large number of U.S. cases associated with raspberries imported from Guatemala. Molecular markers exist for tracing the epidemiology of many of the bacterial pathogens associated with water-borne or food-borne diarrhea, such as serotyping and pulsed-field electrophoresis. However, there are currently no molecular markers available for C. cayetanensis. The intervening transcribed spacer (ITS) regions between the small- and large-subunit rRNA genes demonstrate much greater sequence variability than the small-subunit rRNA sequence itself and have been useful for the molecular typing of other organisms. Thus, ITS1 variability might allow the identification of different genotypes of C. cayetanensis. In order to determine the degree of ITS1 variability among C. cayetanensis isolates, the ITS1 sequences of C. cayetanensis isolates from a variety of sources, including raspberry-associated cases, cases from Guatemala, and pooled and individual isolates from Peru, were obtained. The ITS1 sequences of all five raspberry-associated isolates were identical, consistent with their origin from a single source. In contrast, one of the two Guatemala isolates and two Peruvian isolates contained multiple ITS1 sequences. These multiple sequences could represent multiple clones from a single clinical source or, more likely, variability of the ITS1 region within the genome of a single clone.
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Affiliation(s)
- R D Adam
- Department of Medicine and Microbiology/Immunology, University of Arizona College of Medicine, Tucson, Arizona, USA.
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28
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Abstract
The coccidium Cryptosporidium parvum is an obligate intracellular parasite of the phylum Apicomplexa. It infects the gastrointestinal tract of humans and livestock, and represents the third major cause of diarrhoeal disease worldwide. Scarcely considered for decades due to its apparently non-pathogenic nature, C. parvum has been studied very actively over the last 15 years, after its medical relevance as a dangerous opportunistic parasite and widespread water contaminant was fully recognised. Despite the lack of an efficient in vitro culture system and appropriate animal models, significant advances have been made in this relatively short period of time towards understanding C. parvum biology, immunology, genetics and epidemiology. Until recently, very little was known about the genome of C. parvum, with even basic issues, such as the number and size of chromosomes, being the object of a certain controversy. With the advent of pulsed field gradient electrophoresis and the introduction of molecular biology techniques, the overall structure and fine organisation of the genome of C. parvum have started to be disclosed. Organised into eight chromosomes distributed in a very narrow range of molecular masses, the genome of C. parvum is one of the smallest so far described among unicellular eukaryotic organisms. Although fewer than 30 C. parvum genes have been cloned so far, information about the overall structure of the parasite genome has increased exponentially over the last 2 years. From the first karyotypic analyses to the recent development of physical maps for individual chromosomes, this review will try to describe the state-of-the-art of our knowledge on the nuclear genome of C. parvum and will discuss the available experimental evidence concerning the presence of extra-chromosomal elements.
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Affiliation(s)
- F Spano
- Istituto di Parassitologia, Università di Roma "La Sapienza", P. le A. Moro, 5, Box 6 Roma 62, 00185, Rome, Italy
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29
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Cacciò S, Camilli R, La Rosa G, Pozio E. Establishing the Cryptosporidium parvum karyotype by NotI and SfiI restriction analysis and Southern hybridization. Gene X 1998; 219:73-9. [PMID: 9757000 DOI: 10.1016/s0378-1119(98)00376-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The molecular karyotype of the coccidian parasite Cryptosporidium parvum has proven difficult to study because chromosomes of similar sizes migrate together when submitted to pulsed-field gel electrophoresis (PFGE). In the present work, the karyotype was studied by restriction of chromosome-sized DNA with the rare-cutting enzymes NotI and SfiI, followed by PFGE separation of the restriction fragments and Southern hybridization. These experiments showed that the C. parvum karyotype is formed by eight chromosomes, ranging in size from approximately 0.95 to 1.45 million base pairs (Mbp), accounting for a genome size of 9.6Mbp. As a first step towards the construction of a physical map of the C. parvum genome, a total of 20 probes, including 16 genes and the ribosomal DNA (rDNA) sequence, was mapped to intact chromosomes and to their restriction fragments. In this way, all chromosomes, but one, were identified by specific markers. A comparison of mapping data of homologous genes from different species belonging to the phylum Apicomplexa showed differences in the distribution of rDNA sequences and in the chromosomal localization of alpha- and beta-tubulin genes. The variation in genome size among these parasites is also discussed.
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Affiliation(s)
- S Cacciò
- Laboratory of Parasitology, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy.
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30
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Le Blancq SM, Khramtsov NV, Zamani F, Upton SJ, Wu TW. Ribosomal RNA gene organization in Cryptosporidium parvum. Mol Biochem Parasitol 1997; 90:463-78. [PMID: 9476794 DOI: 10.1016/s0166-6851(97)00181-3] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cytoplasmic ribosomal RNA (rRNA) genes of the Apicomplexan protozoan parasite Cryptosporidium parvum have been analyzed with respect to size, copy number, organization and structure. The small and large subunit rRNAs are 1.7 and 3.6 kb, respectively. A 151 bp putative 5.8S rRNA gene was identified. The rDNA unit is 5' small subunit rRNA internal transcribed spacer 1-5.8S rRNA-internal transcribed spacer 2-large subunit rRNA 3'. There are five copies of the rDNA unit per haploid genome and they are not organized in a conventional head to tail tandem array with a conserved external transcribed spacer. The rDNA units are dispersed through the genome to at least three chromosomes. At least two of the rDNA units are single unlinked copies on different chromosomes. There are two structurally distinct types of rDNA unit, Type A and B, with marked differences in the internal transcribed spacer regions. There are four copies of the Type A rDNA unit and one copy of the Type B rDNA unit.
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MESH Headings
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Chromosome Mapping
- Cryptosporidium parvum/chemistry
- Cryptosporidium parvum/genetics
- Cytoplasm
- DNA, Protozoan/chemistry
- DNA, Protozoan/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Genes, Protozoan
- Genetic Markers
- Karyotyping
- Molecular Sequence Data
- RNA, Protozoan/chemistry
- RNA, Protozoan/genetics
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- Sequence Analysis
- Sequence Analysis, DNA
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Affiliation(s)
- S M Le Blancq
- Division of Environmental Health Sciences, Columbia University School of Public Health, New York, NY 10032, USA.
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31
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Jones SH, Lew AE, Jorgensen WK, Barker SC. Babesia bovis: genome size, number of chromosomes and telomeric probe hybridisation. Int J Parasitol 1997; 27:1569-73. [PMID: 9467743 DOI: 10.1016/s0020-7519(97)00099-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pulsed field gel electrophoresis of intact chromosomes of Babesia bovis revealed four chromosomes in the haploid genome. A telomere probe, derived from Plasmodium berghei, hybridised to eight SfiI restriction fragments of genomic B. bovis DNA digests indicating the presence of four chromosomes. A small subunit (18S) ribosomal RNA gene probe hybridised to the third chromosome only. The genome size of B. bovis is estimated to be 9.4 million base pairs. The sizes of chromosomes 1, 2, 3 and 4 are estimated to be 1.4, 2.0, 2.8 and 3.2 million base pairs, respectively.
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Affiliation(s)
- S H Jones
- Department of Parasitology, University of Queensland, Brisbane, Australia
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32
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Lew AE, Dalrymple BP, Jeston PJ, Bock RE. PCR methods for the discrimination of Babesia bovis isolates. Vet Parasitol 1997; 71:223-37. [PMID: 9299692 DOI: 10.1016/s0304-4017(97)00025-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Three different polymerase chain reaction assays for the typing of isolates of Babesia bovis have been developed and compared with a hybridisation based method. Primers were designed within conserved regions flanking the variable length tandem repeats of the Bv80 and BvVA1 genes. For the long array of repeats in BvVA1, up to 7.5 kb, a modified long template PCR method was developed. The assays were compared using ten independent isolates of Babesia bovis. Using the BvVA1 and Bv80 PCR assays, 13 and 10 genotypes could be discriminated, respectively, with some isolates containing several genotypes. Combining the two PCR assays, 17 genotypes were identified within the ten Babesia bovis isolates. Whilst simpler and requiring less DNA, the BvVA1 PCR analysis exhibited significant bias towards some genotypes of the BvVA1 repeats. Further discrimination of BvVA1 PCR products was achieved using AccI digests producing population specific ladders. Genomic DNA fingerprints were also generated by PCR of DNA using an arbitrary primer (randomly amplified polymorphic DNA, RAPD) revealing polymorphic genotypes that were isolate specific. No amplification of host DNA resulted from any of the three PCR procedures. Babesia bigemina DNA was not amplified by the Bv80 or BvVA1 primers. Applications demonstrating changes in composition of populations of Babesia bovis parasites during attenuation and prolonged culture maintenance are described.
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Affiliation(s)
- A E Lew
- Animal Research Institute, Queensland Department of Primary Industries, Moorooka, Australia.
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Calder JA, Reddy GR, Chieves L, Courtney CH, Littell R, Livengood JR, Norval RA, Smith C, Dame JB. Monitoring Babesia bovis infections in cattle by using PCR-based tests. J Clin Microbiol 1996; 34:2748-55. [PMID: 8897177 PMCID: PMC229398 DOI: 10.1128/jcm.34.11.2748-2755.1996] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The sensitivity and specificity of PCR tests based on the small-subunit rRNA gene sequence of Babesia bovis were compared in a blind study of experimentally infected cattle with the corresponding parameters of the complement fixation (CF) test currently used in the United States to screen for bovine babesiosis. Cattle were experimentally infected with a single inoculum of a cloned laboratory strain of B. bovis. Blood samples were collected and tested over a period covering from the day of infection to 10 months postinfection. The level of parasitemia (percent infected erythrocytes) present in each sample was estimated from test results and was plotted as a function of time postinfection. These data are the first describing the course of infection by methods capable of detecting parasitemias in the range of 10(-7)%, which frequently occur in the carrier state. Parasitemias in the samples tested strongly influenced the sensitivity and negative predictive value of the PCR-based tests which varied with time postinfection. The average sensitivities of the three PCR-based tests for B. bovis ranged from 58 to 70% for a single determination, while the sensitivity of the CF test was only 6%. Both PCR-based and CF tests for B. bovis had high specificity values ranging from 96 to 100%.
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Affiliation(s)
- J A Calder
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville 32611, USA.
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Silins GU, Blakeley RL, Riddles PW. Characterisation of genes encoding a nucleoside monophosphate kinase and a L35 ribosomal protein from Babesia bovis. Mol Biochem Parasitol 1996; 76:231-44. [PMID: 8920009 DOI: 10.1016/0166-6851(95)02561-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have sequenced a region of the Babesia bovis nuclear genome that encodes a L35 ribosomal protein homologue (bl35) and a putative nucleoside monophosphate kinase (bnmk) that is most similar to the adenylate kinase of gram-positive bacteria and the mitochondrial form of adenylate kinase in eukaryotes. BNMK appears to be unique in that it is the first eukaryotic family member to feature a putative zinc-binding domain. bnmk and bl35 are closely linked and transcribed from opposite DNA strands. Examination of the gene structures indicate that the coding regions contain small intervening sequences that obey the GT-AG rule of eukaryotic spliceosomal introns. The single intron separates the bl35 initiation codon from the remainder of the coding region and the 6-exon bnmk gene does not appear to be differentially spliced. Both genes utilise multiple polyadenylation sites and the canonical mammalian polyadenylation signal AATAAA is absent from their 3' untranslated regions. Primer extension analyses reveal that the bnmk gene utilises a cluster of transcription start points, one of which is used most frequently. The bnmk mRNA 5' end does not appear to be cis- or trans-spliced. We report here the first evidence of intronic sequences, as well as heterogeneous 5' and 3' ends for mRNA of a member of the Babesia genus.
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Affiliation(s)
- G U Silins
- Department of Biochemistry, University of Queensland, Australia.
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Affiliation(s)
- D F Mahoney
- CSIRO Division of Tropical Animal Production, Long Pocket Laboratories, Indooroopilly, Queensland
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Kibe MK, ole-MoiYoi OK, Nene V, Khan B, Allsopp BA, Collins NE, Morzaria SP, Gobright EI, Bishop RP. Evidence for two single copy units in Theileria parva ribosomal RNA genes. Mol Biochem Parasitol 1994; 66:249-59. [PMID: 7808475 DOI: 10.1016/0166-6851(94)90152-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacteriophage clones containing ribosomal RNA genes of Theileria parva were isolated from genomic DNA libraries. Physical mapping studies revealed 2 ribosomal DNA units, which were distinguishable by restriction enzyme site polymorphisms in flanking sequences. The cloned ribosomal DNA units were mapped to 2 separate T. parva chromosomes. Analysis of sequences contained in lambda EMBL3 recombinants, together with Southern blot analysis of genomic DNA and data on the copy number of the rRNA genes, suggested that the rDNA units were not tandemly repeated. This organisation of ribosomal transcription units is similar to that described for other genera of apicomplexan protozoa, but 2 rDNA units, each containing single copies of the rRNA coding genes, would be the lowest copy number described for any eukaryote in which amplification of rRNA genes is not known to occur. EcoRI restriction fragment length polymorphisms, which were revealed using rRNA gene probes, separated T. parva stocks into 2 categories. Nucleotide sequence analysis of polymerase chain reaction-amplified internal transcribed spacer DNA revealed 2 different ITS sequences derived from rDNA transcription units within the genome of a cloned T. parva parasite. Polymorphism was also observed between ITS sequences amplified from the DNA of different T. parva stocks. A synthetic oligonucleotide derived from T. parva Uganda ribosomal ITS DNA sequences hybridised to DNA from the T. parva Uganda stock, but not to the DNA of the T. parva Muguga stock. This oligonucleotide is potentially useful as a marker for the T. parva Uganda stock.
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Affiliation(s)
- M K Kibe
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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Hill SM, Crampton JM. DNA-based methods for the identification of insect vectors. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1994; 88:227-50. [PMID: 7944669 DOI: 10.1080/00034983.1994.11812864] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Many insect vectors are members of complexes composed of morphologically identical sibling species. The identification of individual species, a requirement of epidemiological studies and control programmes, has traditionally relied upon techniques such as chromosomal analysis or isoenzyme typing. Owing to the limitations of these techniques, the last few years have seen many developments in DNA-based technologies for identification. DNA-based protocols have advantages over the other techniques utilized, in that they may identify all insect stages of both sexes using alcohol-preserved, dried, fresh or frozen specimens. The methods ultimately rely upon either DNA probe hybridization or the polymerase chain reaction (PCR). This review describes a number of approaches taken towards the development of these techniques. The aim of these approaches, whether directed or random, is to produce a methodology that is cheap, accurate and easy to use. In this review, the DNA-based techniques developed for the identification of Anopheles gambiae complex mosquitoes are used to illustrate the power of these methods, although, as the review demonstrates, the technology is directly applicable to many other mosquito or insect vectors. In addition, the methods discussed may be utilized for generating additional epidemiological data, such as identification of parasites within the vector or origin of the bloodmeal. A comprehensive survey of the probe systems available for the identification of insect vectors and the disease-causing organisms they transmit to the human population is therefore included. Given further advances in this technology, it may be anticipated that DNA-based approaches to identification may eventually supersede more traditional methodologies in the fields of tropical medicine and parasitology.
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Affiliation(s)
- S M Hill
- Wolfson Unit of Molecular Genetics, School of Tropical Medicine, Liverpool, U.K
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Bishop RP, Sohanpal BK, Allsopp BA, Spooner PR, Dolan TT, Morzaria SP. Detection of polymorphisms among Theileria parva stocks using repetitive, telomeric and ribosomal DNA probes and anti-schizont monoclonal antibodies. Parasitology 1993; 107 ( Pt 1):19-31. [PMID: 8102796 DOI: 10.1017/s0031182000079361] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A total of 21 Theileria parva stocks from 6 countries were characterized using T. parva repetitive and ribosomal DNA probes, a Plasmodium berghei telomeric oligonucleotide and a panel of anti-schizont monoclonal antibodies (MAbs). Hybridization of the repetitive DNA probe to Southern blots of EcoRI-digested T. parva DNA revealed 20 different restriction fragment patterns among DNA samples isolated from infections initiated using 16 parasite stocks. The panel of anti-schizont MAbs defined 8 different profiles among schizont-infected lymphoblastoid cell-cultures infected with the same 16 T. parva stocks. Many stocks, which were differentiated by the repetitive DNA probe, could not be distinguished using the anti-schizont MAbs. A cloned T. parva small subunit ribosomal RNA (SSUrRNA) gene probe separated 17 T. parva stocks into 2 groups, exhibiting either 1 or 2 restriction fragments, when hybridized to EcoRI-digested T. parva DNA. When hybridized to PvuII-digested DNA from 8 T. parva stocks, the ribosomal probe identified 4 groups with similar restriction fragment patterns. A synthetic oligonucleotide derived from a P. berghei telomeric sequence hybridized to 7 or 8 size-polymorphic restriction fragments in the EcoRI-digested DNA of most T. parva stocks. The telomeric and ribosomal probes defined the same 4 groups among 8 T. parva stocks as assessed by similarities in restriction fragment patterns. Based on the comparison of repetitive DNA sequences from the T. parva Uganda and Muguga stocks, a synthetic oligonucleotide was developed which distinguished the DNA of the T. parva Uganda stock from that of 4 other T. parva stocks on a positive/negative basis.
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Affiliation(s)
- R P Bishop
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Dalrymple BP, Casu RE, Peters JM, Dimmock CM, Gale KR, Boese R, Wright IG. Characterisation of a family of multi-copy genes encoding rhoptry protein homologues in Babesia bovis, Babesia ovis and Babesia canis. Mol Biochem Parasitol 1993; 57:181-92. [PMID: 8433711 DOI: 10.1016/0166-6851(93)90194-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A monoclonal antibody that had been raised against a protease-containing fraction of Babesia bovis, and shown to bind to a protein located in the rhoptries, was used to screen a B. bovis cDNA expression library. The sequence of the protein encoded by a positive clone was almost identical to the equivalent region of a previously described B. bovis 60-kDa rhoptry protein (Bv60). A tandem repeat of the gene encoding Bv60 was identified in all Australian isolates of B. bovis examined. Genes encoding homologous of Bv60 were cloned from Babesia ovis and Babesia canis. In B. ovis, 5 closely linked genes were identified. Four of these genes appeared to encode very similar proteins (Bo60.1-4). The protein (Bo60.5) encoded by the fifth B. ovis gene had 72% amino acid identity to Bo60.1-4 in the amino-terminal 306 amino acids, but no significant similarities in the carboxy-terminal region. In B. canis one gene (Bc60.2) was sequenced and a second closely linked gene was identified. A further member of the family, p58, has also been described previously from Babesia bigemina. Tandemly repeated genes subject to extensive gene conversion appear to be a feature of this family of babesial rhoptry protein homologous. No proteins significantly related to any members of the gene family were identified in a search of translated DNA and protein sequence databases. Thus the function of this family of proteins remains a matter for speculation.
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Affiliation(s)
- B P Dalrymple
- Commonwealth Scientific and Industrial Research Organisation, Division of Tropical Animal Production, Indooroopilly, QLD, Australia
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Dalrymple BP, Dimmock CM, Parrodi F, Wright IG. Babesia bovis, Babesia bigemina, Babesia canis, Babesia microti and Babesia rodhaini: comparison of ribosomal RNA gene organization. Int J Parasitol 1992; 22:851-5. [PMID: 1428519 DOI: 10.1016/0020-7519(92)90139-c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The three ribosomal DNA (rDNA) units have been cloned from an Australian isolate of Babesia bigemina. The organization of the units is very similar to that reported for a Mexican isolate of B. bigemina. In Babesia canis four rDNA units have been identified. Both Babesia rodhaini and Babesia microti contain two different rDNA units. A small number of different rDNA units appears to be a common feature of this group of Protozoa. Restriction enzyme analysis of the rDNA units form these species and B. bovis suggests that the genus Babesia as currently defined does indeed include two distinct groups of organisms namely, B. bovis, B. bigemina and B. canis and B. rodhaini and B. microti.
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Affiliation(s)
- B P Dalrymple
- CSIRO Division of Tropical Animal Production, Indooroopilly, Queensland, Australia
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Dalrymple BP, Jorgensen WK, de Vos AJ, Wright IG. Analysis of the composition of samples of Babesia bovis and the influence of different environmental conditions on genetically distinct subpopulations. Int J Parasitol 1992; 22:731-7. [PMID: 1428506 DOI: 10.1016/0020-7519(92)90121-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A recombinant DNA probe specific for a tandemly repeated sequence located within the BoVA1 gene of Babesia bovis was used to analyse 10 independent samples of B. bovis. Twelve different alleles of the BoVA1 gene and flanking regions were identified in the 18 different subpopulations analysed. Most samples of B. bovis originally derived from single animals contained more than one genetically distinct subpopulation. However, only one population of parasites was identified in samples of the Ka line used in Australia from 1979 until 1990 as the live attenuated vaccine strain. In contrast, the replacement attenuated vaccine line, Ta, contained two genetically distinct subpopulations of parasites. Changes in the ratios of subpopulations of parasites were identified during attenuation and under different culture conditions. Batch-to-batch variation in the composition of doses of the live attenuated vaccine may lead to differences in efficacy and in severity of the infection associated with vaccination.
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Affiliation(s)
- B P Dalrymple
- CSIRO Division of Tropical Animal Production, Indooroopilly, Queensland, Australia
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Ellis J, Hefford C, Baverstock PR, Dalrymple BP, Johnson AM. Ribosomal DNA sequence comparison of Babesia and Theileria. Mol Biochem Parasitol 1992; 54:87-95. [PMID: 1518535 DOI: 10.1016/0166-6851(92)90097-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Previous studies on the taxonomy of Babesia spp. (phylum Apicomplexa) using morphological and life cycle characteristics have resulted in their classification into 3 subgenera, with the genus Theileria being most closely related to them. Using a strategy based on the direct sequence analysis of products derived by asymmetric PCR to determine the nucleotide sequences, we have tested the validity of this classification by sequencing the small subunit ribosomal RNA genes amplified from 2 Babesia species, namely Babesia bovis and Babesia rodhaini, and comparing these with previously published sequences of Theileria annulata and Babesia bigemina using Plasmodium falciparum as an outgroup. The results of this phylogenetic analysis support the recognition of at least 2 genera in Babesia--one to include B. bigemina and B. bovis, the other to include B. rodhaini.
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Affiliation(s)
- J Ellis
- Department of Microbiology and Infectious Diseases, Flinders University Medical School, Bedford Park, South Australia
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Dalrymple BP. Diversity and selection in Babesia bovis and their impact on vaccine use. ACTA ACUST UNITED AC 1992; 8:21-3. [PMID: 15463521 DOI: 10.1016/0169-4758(92)90306-m] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In the past few years the prospect of a recombinant vaccine effective against the cattle hoemoparosite Babesia bovis has almost become a reality. However, in Australia, vaccination with live parasites has been practised since before the turn of the century and it has recently been proposed that selection of parasites resistant to immunity induced by the B. bovis line Ka (since 1979 the only component of the live attenuated vaccine) may have occurred. Brian Dalrymple examines the evidence for and against this proposal and discusses examples of strain diversity and variation and their effect on the long-term viability of defined attenuated and recombinant vaccines.
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Affiliation(s)
- B P Dalrymple
- Division of Tropical Animal Production, Long Pocket Laboratories, Private Bag No. 3, PO, Indooroopilly, Queensland 4068, Australia
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Reddy GR, Chakrabarti D, Yowell CA, Dame JB. Sequence microheterogeneity of the three small subunit ribosomal RNA genes of Babesia bigemina: expression in erythrocyte culture. Nucleic Acids Res 1991; 19:3641-5. [PMID: 1840661 PMCID: PMC328392 DOI: 10.1093/nar/19.13.3641] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Three distinct ribosomal RNA (rRNA) transcription units (rDNA units), designated A, B and C, were identified in the intraerythrocytic protozoan parasite, Babesia bigemina. These rDNA units were cloned, and restriction maps were constructed showing the approximate location of the small and large rRNA coding regions. The arrangement of the genes in the genome and copy number analysis suggests the presence of a single copy of each rDNA unit per haploid genome. The complete nucleotide sequence of the small subunit rRNA coding region (1693 bp) and parts of the 5' and 3' flanking regions were determined for all three units. Units A and B have identical sequences, but unit C differs from units A and B at ten nucleotide positions, two in the small subunit rRNA coding region and four each in the adjacent 5' and 3' flanking regions. The differences in the coding region are confirmed in genomic DNA and RNA from two different isolates of B.bigemina. The RNA of both sequence types is transcribed in parasites from erythrocyte culture, however, the products of gene units A + B accumulate at a ratio of approximately 4:1 compared with the product of unit C.
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Affiliation(s)
- G R Reddy
- Department of Infectious Diseases, College of Veterinary Medicine, University of Florida, Gainesville 32611
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