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Salih DA, Ali AM, Njahira M, Taha KM, Mohammed MS, Mwacharo JM, Mbole-Kariuki N, El Hussein AM, Bishop R, Skilton R. Population Genetic Analysis and Sub-Structuring of Theileria annulata in Sudan. Front Genet 2021; 12:742808. [PMID: 34868214 PMCID: PMC8640526 DOI: 10.3389/fgene.2021.742808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/25/2021] [Indexed: 11/15/2022] Open
Abstract
Theileria annulata, which causes tropical theileriosis, is a major impediment to improving cattle production in Sudan. Tropical theileriosis disease is prevalent in the north and central regions of Sudan. Outbreaks of the disease have been observed outside the known endemic areas, in east and west regions of the country, due to changes in tick vector distribution and animal movement. A live schizont attenuated vaccination based on tissue culture technology has been developed to control the disease. The parasite in the field as well as the vaccine strain need to be genotyped before the vaccinations are practiced, in order to be able to monitor any breakthrough or breakdown, if any, after the deployment of the vaccine in the field. Nine microsatellite markers were used to genotype 246 field samples positive for T. annulata DNA and the vaccine strain. North and central populations have a higher multiplicity of infection than east and west populations. The examination of principal components showed two sub-structures with a mix of all four populations in both clusters and the vaccine strain used being aligned with left-lower cluster. Only the north population was in linkage equilibrium, while the other populations were in linkage disequilibrium, and linkage equilibrium was found when all samples were regarded as single population. The genetic identity of the vaccine and field samples was 0.62 with the north population and 0.39 with west population. Overall, genetic investigations of four T. annulata populations in Sudan revealed substantial intermixing, with only two groups exhibiting regional origin independence. In the four geographically distant regions analyzed, there was a high level of genetic variation within each population. The findings show that the live schizont attenuated vaccine, Atbara strain may be acceptable for use in all Sudanese regions where tropical theileriosis occurs.
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Affiliation(s)
- Diaeldin A Salih
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub (BecA-ILRI Hub), Nairobi, Kenya.,Central Veterinary Research Laboratory, Khartoum, Sudan
| | - Awadia M Ali
- Faculty of Veterinary Medicine, University of Khartoum, Khartoum, Sudan
| | - Moses Njahira
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub (BecA-ILRI Hub), Nairobi, Kenya
| | - Khalid M Taha
- Atbara Veterinary Research Laboratory, Atbara, Sudan
| | | | - Joram M Mwacharo
- School of Life Sciences, Centre for Genetics and Genomics, University of Nottingham, Nottingham, United Kingdom
| | | | | | - Richard Bishop
- International Livestock Research Institute, Nairobi, Kenya
| | - Robert Skilton
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub (BecA-ILRI Hub), Nairobi, Kenya
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Skilton R, Gao Y. Combining object detection with generative adversarial networks for in-component anomaly detection. Fusion Engineering and Design 2020. [DOI: 10.1016/j.fusengdes.2020.111736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Pangione L, Skilton R, Powell R. A taxonomy approach to failure mode analysis for use in predictive condition monitoring. Fusion Engineering and Design 2020. [DOI: 10.1016/j.fusengdes.2020.111506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Li M, Wu H, Handroos H, Skilton R, Hekmatmanesh A, Loving A. Deformation modeling of manipulators for DEMO using artificial neural networks. Fusion Engineering and Design 2019. [DOI: 10.1016/j.fusengdes.2019.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Jonasson ET, Boeuf J, Kyberd S, Skilton R, Burroughes G, Amayo P, Collins S. Reconstructing JET using LIDAR-Vision fusion. Fusion Engineering and Design 2019. [DOI: 10.1016/j.fusengdes.2019.03.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Pagani P, Fischer G, Farquhar I, Skilton R, Mittwollen M. A logistical simulation tool to quantitatively evaluate the effect of different maintenance solutions on the total maintenance downtime for fusion reactors. Fusion Engineering and Design 2019. [DOI: 10.1016/j.fusengdes.2019.02.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Skilton R, Hamilton N, Howell R, Lamb C, Rodriguez J. MASCOT 6: Achieving high dexterity tele-manipulation with a modern architectural design for fusion remote maintenance. Fusion Engineering and Design 2018. [DOI: 10.1016/j.fusengdes.2018.03.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Li M, Wu H, Handroos H, Wang Y, Loving A, Crofts O, Coleman M, Skilton R, Burroughes G, Keep J. Dynamic model identification method of manipulators for inside DEMO engineering. Fusion Engineering and Design 2017. [DOI: 10.1016/j.fusengdes.2017.02.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kyallo M, Ateka EM, Sseruwagi P, Ascencio-Ibáñez JT, Ssemakula MO, Skilton R, Ndunguru J. Infectivity of Deinbollia mosaic virus, a novel weed-infecting begomovirus in East Africa. Arch Virol 2017; 162:3439-3445. [PMID: 28791544 PMCID: PMC5640732 DOI: 10.1007/s00705-017-3495-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/09/2017] [Indexed: 11/25/2022]
Abstract
Weed-infecting begomoviruses play an important role in the epidemiology of crop diseases because they can potentially infect crops and contribute to the genetic diversity of crop-infecting begomoviruses. Despite the important epidemiological role that weed-infecting begomoviruses play, they remain insufficiently studied in Africa. Recently, we identified Deinbollia mosaic virus (DMV), a distinct begomovirus found naturally infecting the weed host Deinbollia borbonica (Sapindaceae) in Kenya and Tanzania. In this study, we investigated the capacity of DMV to infect a restricted host range of Solanaceae and Euphorbiaceae species. Biolistic inoculation of Nicotiana benthamiana with concatemeric DNAs resulted in systemic infection associated with yellow mosaic symptoms, while DNA partial dimers caused asymptomatic systemic infection. DMV was not infectious to cassava (Manihot esculenta Crantz), suggesting host resistance to the virus. Here, we demonstrate the first experimental infectivity analysis of DMV in N. benthamiana and cassava.
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Affiliation(s)
- Martina Kyallo
- Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub, P.O. Box 30709-00100, Nairobi, Kenya.
| | - Elijah Miinda Ateka
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
| | - José Trinidad Ascencio-Ibáñez
- Department of Molecular and Structural Biochemistry, North Carolina State University, 132 Polk Hall, Raleigh, NC, 27695, USA
| | | | - Robert Skilton
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Joseph Ndunguru
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
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Ayagirwe B, Meutchieye F, Djikeng A, Skilton R, Osama S, Manjeli Y. Genetic Diversity and Structure of Domestic Cavy ( Cavia porcellus) Populations from Smallholder Farms in Southern Cameroon. J Anim Prod 2017; 19:JAP-19-01-001. [PMID: 33384573 PMCID: PMC7771548 DOI: 10.20884/1.jap.2017.19.1.585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although domestic cavies are widely used in sub-Saharan Africa as a source of meat and income, there are only a few studies of their population structure and genetic relatedness. This seminal study was designed with the main objective to assess the genetic diversity and determine the population structure of cavy populations from Cameroon to guide the development of a cavy improvement program. Sixteen microsatellite markers were used to genotype 109 individuals from five cavy populations (Wouri, Moungo and Nkongsamba in the Littoral region, and Mémé and Fako in the Southwest region of Cameroon). Twelve markers worked in the five populations with a total of 17 alleles identified, with a range of 2.9 to 4.0 alleles per locus. Observed heterozygosity (from 0.022 to 0.277) among populations was lower than expected heterozygosity (from 0.42 to 0.54). Inbreeding rates between individuals of the populations and between individuals in each population were 59.3% and 57.2%, respectively, against a moderate differentiation rate of 4.9%. All the tested loci deviated from Hardy-Weinberg equilibrium, except for locus 3. Genetic distances between populations were small (from 0.008 to 0.277), with a high rate of variability among individuals within each population (54.4%). Three distinct genetic groups were structured. This study has shown that microsatellites are useful for the genetic characterization of cavy populations in Cameroon and that the populations investigated have sufficient genetic diversity that can be used to be deployed as a basis for weight, prolificacy and disease resistance improvement. The genetic of diversity in Southern Cameroon is wide and constitute an opportunity for cavy breeding program.
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Affiliation(s)
- Basengere Ayagirwe
- Department of Animal Production, Faculty of
Agriculture and Environmental Studies, Evangelical University in Africa, Bukavu,
The Democratic Republic of the Congo
- Department of Animal Production, Faculty of
Agronomy and Agricultural Sciences, University of Dschang, Cameroon
| | - Felix Meutchieye
- Department of Animal Production, Faculty of
Agronomy and Agricultural Sciences, University of Dschang, Cameroon
| | - Appolinaire Djikeng
- Biosciences Eastern and Central Africa -
International Livestock Research Institute (BecA-ILRI), Nairobi, Kenya
| | - Robert Skilton
- International Centre of Insect Physiology and
Ecology (icipe), Nairobi, Kenya
| | - Sarah Osama
- Biosciences Eastern and Central Africa -
International Livestock Research Institute (BecA-ILRI), Nairobi, Kenya
| | - Yacouba Manjeli
- Department of Animal Production, Faculty of
Agronomy and Agricultural Sciences, University of Dschang, Cameroon
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Babajide JM, Maina S, Kiawa B, Skilton R. Identification of fungal isolates from steeped yam (Gbodo): Predominance of Meyerozyma guilliermondii. Food Sci Biotechnol 2015. [DOI: 10.1007/s10068-015-0133-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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13
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Gill P, Skilton R, Day T, Harding D, Iredale R. 149 The Tenovus nurse-led cancer call back service. Eur J Oncol Nurs 2014. [DOI: 10.1016/s1462-3889(14)70168-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Githaka N, Konnai S, Skilton R, Kariuki E, Kanduma E, Murata S, Ohashi K. Genotypic variations in field isolates of Theileria species infecting giraffes (Giraffa camelopardalis tippelskirchi and Giraffa camelopardalis reticulata) in Kenya. Parasitol Int 2013; 62:448-53. [DOI: 10.1016/j.parint.2013.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/27/2013] [Accepted: 06/05/2013] [Indexed: 11/26/2022]
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Weir W, Sunter J, Chaussepied M, Skilton R, Tait A, de Villiers EP, Bishop R, Shiels B, Langsley G. Highly syntenic and yet divergent: A tale of two Theilerias. Infection, Genetics and Evolution 2009; 9:453-61. [DOI: 10.1016/j.meegid.2009.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
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16
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Odongo D, Kamau L, Skilton R, Mwaura S, Nitsch C, Musoke A, Taracha E, Daubenberger C, Bishop R. Vaccination of cattle with TickGARD induces cross-reactive antibodies binding to conserved linear peptides of Bm86 homologues in Boophilus decoloratus. Vaccine 2006; 25:1287-96. [PMID: 17070625 DOI: 10.1016/j.vaccine.2006.09.085] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 09/07/2006] [Accepted: 09/28/2006] [Indexed: 11/17/2022]
Abstract
Vaccines based on recombinant Bm86 gut antigen from Boophilus microplus are a useful component of integrated control strategies against B. microplus infestations of cattle. The capacity of such vaccines to control heterologous infestations by two African tick species was investigated. The mean weight of engorged female ticks and mean egg mass per tick were significantly reduced in B. decoloratus infestations, but there was no effect of the vaccine against adult Rhipicephalus appendiculatus. We cloned, sequenced and expressed two Bm86 homologues (Bd86) from B. decoloratus. Amino acid sequence identity between Bd86 homologues (Bd86-1 and Bd86-2) and Bm86 was 86% and 85%, respectively, compared to 93% identity between the variants. Native Bd86 protein in B. decoloratus tick mid-gut sections and recombinant Bd86-1 reacted strongly with sera from TickGARD vaccinated cattle. TickGARD can therefore protect against a heterologous tick species with multiple antigen sequences. Epitope mapping using sera from TickGARD-vaccinated cattle identified two linear peptides conserved between the Bd86 homologues and Bm86. These epitopes represent candidate synthetic peptide vaccines for control of Boophilus spp. and the pathogens transmitted by these tick vectors.
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Affiliation(s)
- David Odongo
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya.
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17
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Lambson B, Nene V, Obura M, Shah T, Pandit P, Ole-Moiyoi O, Delroux K, Welburn S, Skilton R, de Villiers E, Bishop R. Identification of candidate sialome components expressed in ixodid tick salivary glands using secretion signal complementation in mammalian cells. Insect Mol Biol 2005; 14:403-14. [PMID: 16033433 DOI: 10.1111/j.1365-2583.2005.00571.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ixodid ticks manipulate mammalian host pathways by secreting molecules from salivary glands. Novel cDNAs containing functional secretion signals were isolated from ixodid tick salivary glands using a signal sequence trap. Only 15/61 Rhipicephalus appendiculatus and 1/7 Amblyomma variegatum cDNAs had significant identity (< 1e-15) to previously identified sequences. Polypeptides that may interact with host pathways included a kinase inhibitor. Two proteins encoded homologues of the yolk protein vitellogenin and seventeen contained glycine-rich motifs. Four proteins without sequence matches had conserved structural folds, identified using a Threading algorithm. Predicted secretion signals were between fifteen and fifty-seven amino acids long. Four homologous polymorphic proteins contained conserved (26/27 residues) signal peptides. Ten functional tick secretion signals could not be unambiguously identified using predictive algorithms.
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Affiliation(s)
- B Lambson
- The International Livestock Research Institute (ILRI), Nairobi, Kenya
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Skilton R. Reforming the consultant contract again? Fees for service have been in effect for some time. BMJ 2004; 329:1343. [PMID: 15576753 PMCID: PMC534886 DOI: 10.1136/bmj.329.7478.1343-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Nene V, Lee D, Kang'a S, Skilton R, Shah T, de Villiers E, Mwaura S, Taylor D, Quackenbush J, Bishop R. Genes transcribed in the salivary glands of female Rhipicephalus appendiculatus ticks infected with Theileria parva. Insect Biochem Mol Biol 2004; 34:1117-1128. [PMID: 15475305 DOI: 10.1016/j.ibmb.2004.07.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Revised: 06/30/2004] [Accepted: 07/01/2004] [Indexed: 05/24/2023]
Abstract
We describe the generation of an auto-annotated index of genes that are expressed in the salivary glands of four-day fed female adult Rhipicephalus appendiculatus ticks. A total of 9162 EST sequences were derived from an uninfected tick cDNA library and 9844 ESTs were from a cDNA library from ticks infected with Theileria parva, which develop in type III salivary gland acini. There were no major differences between abundantly expressed ESTs from the two cDNA libraries, although there was evidence for an up-regulation in the expression of some glycine-rich proteins in infected salivary glands. Gene ontology terms were also assigned to sequences in the index and those with potential enzyme function were linked to the Kyoto encyclopedia of genes and genomes database, allowing reconstruction of metabolic pathways. Several genes code for previously characterized tick proteins such as receptors for myokinin or ecdysteroid and an immunosuppressive protein. cDNAs coding for homologs of heme-lipoproteins which are major components of tick hemolymph were identified by searching the database with published N-terminal peptide sequence data derived from biochemically purified Boophilus microplus proteins. The EST data will be a useful resource for construction of microarrays to probe vector biology, vector-host and vector-pathogen interactions and to underpin gene identification via proteomics approaches.
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Affiliation(s)
- Vishvanath Nene
- Parasite Genomics Department, The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
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Skilton R. Sterilisation of laryngoscope blades. Anaesthesia 2003; 58:921-2. [PMID: 12911380 DOI: 10.1046/j.1365-2044.2003.03362_13.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nene V, Lee D, Quackenbush J, Skilton R, Mwaura S, Gardner MJ, Bishop R. AvGI, an index of genes transcribed in the salivary glands of the ixodid tick Amblyomma variegatum. Int J Parasitol 2002; 32:1447-56. [PMID: 12392910 DOI: 10.1016/s0020-7519(02)00159-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Random clones from a cDNA library made from mRNA purified from dissected salivary glands of feeding female Amblyomma variegatum ticks were subjected to single pass sequence analysis. A total of 3992 sequences with an average read length of 580 nucleotides have been used to construct a gene index called AvGI that consists of 2109 non-redundant sequences. A provisional gene identity has been assigned to 39% of the database entries by sequence similarity searches against a non-redundant amino acid database and a protein database that has been assigned gene ontology terms. Homologs of genes encoding basic cellular functions including previously characterised enzyme activities, such as stearoyl CoA saturase and protein phosphatase, of ixodid tick salivary glands were found. Several families of abundant cDNA sequences that may code for protein components of tick cement and A. variegatum proteins which may contribute to anti-haemostatic and anti-inflammatory responses, and, one with potential immunosuppressive activity, were also identified. Interference with the function of such proteins might disrupt the life cycle of A. variegatum and help to control this ectoparasite or to reduce its ability to transmit disease causing organisms. AvGI represents an electronic knowledge base, which can be used to launch investigations of the biology of the salivary glands of this tick species. The database may be accessed via the World Wide Web at http://www.tigr.org/tdb/tgi.shtml.
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Affiliation(s)
- Vishvanath Nene
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
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Bishop R, Geysen D, Skilton R, Odongo D, Nene V, Allsopp B, Mbogo S, Spooner P, Morzaria S. Genomic Polymorphism, Sexual Recombination and Molecular Epidemiology of Theileria Parva. ACTA ACUST UNITED AC 2002. [DOI: 10.1007/978-1-4615-0903-5_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Bishop R, Geysen D, Spooner P, Skilton R, Nene V, Dolan T, Morzaria S. Molecular and immunological characterisation of Theileria parva stocks which are components of the 'Muguga cocktail' used for vaccination against East Coast fever in cattle. Vet Parasitol 2001; 94:227-37. [PMID: 11137270 DOI: 10.1016/s0304-4017(00)00404-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The 'Muguga cocktail' which is composed of three Theileria parva stocks Muguga, Kiambu 5 and Serengeti-transformed has been used extensively for live vaccination against East Coast fever in cattle in eastern, central and southern Africa. Herein we describe the molecular characterisation of the T. parva vaccine stocks using three techniques, an indirect fluorescent antibody test with a panel of anti-schizont monoclonal antibodies (MAb), Southern blotting with four T. parva repetitive DNA probes and polymerase chain reaction (PCR)-based assays detecting polymorphism within four single copy loci encoding antigen genes. The Muguga and Serengeti-transformed stocks exhibited no obvious differences in their reactivity with the panel of MAbs, whereas Kiambu 5 differed with several MAbs. Kiambu 5 DNA was very distinct from the Muguga and Serengeti-transformed isolates in the hybridisation pattern with all four nucleic acid probes, whereas Muguga and Serengeti-transformed isolates exhibited minor differences and could not be discriminated with one of the probes. PCR amplification in combination with restriction fragment length polymorphism analysis indicated that Kiambu 5 was also markedly divergent from the Muguga and Serengeti-transformed stocks within two of the four antigen coding genes. The T. parva Serengeti-transformed stock did not contain a 130 base pair insert within the p67 sporozoite antigen gene, which has been observed previously in most T. parva parasites isolated from buffalo, and could not be discriminated from T. parva Muguga at any of the four single copy loci. Collectively the data indicate that two of the cocktail components T. parva Serengeti-transformed and Muguga are genetically closely related, while the third component Kiambu 5 is quite distinct. Based on the findings, there may be a need to include only one of the T. parva Muguga and Serengeti-transformed components in the immunising cocktail. The study demonstrates the value of molecular characterisation data for monitoring of live vaccines.
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Affiliation(s)
- R Bishop
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya.
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Morzaria SP, Katende J, Musoke A, Nene V, Skilton R, Bishop R. Development of sero-diagnostic and molecular tools for the control of important tick-borne pathogens of cattle in Africa. Parassitologia 1999; 41 Suppl 1:73-80. [PMID: 11071549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
Tick-borne diseases (TBDs) are a major economic constraint to livestock production in sub-Saharan Africa. ILRI is focussing on developing a range of products, such as vaccines, diagnostics and decision support services to underpin improved control programmes against these diseases. We have developed three highly sensitive and specific enzyme linked immuno-assays (ELISAs), which allow precise diagnosis of Theileria parva, Babesia bigemina and Anaplasma marginale. These tests have been standardised and validated using defined experimental and field infection sera. Parasite specific recombinant antigens and monoclonal antibodies against bovine immunoglobulins as secondary antibodies have played an important role in in enhancing the sensitivity and specificity of the assays. They have been further evaluated in on-farm longitudinal sero-epidemiological studies to define infection dynamics and disease risks in various farming systems in Kenya and Uganda. In addition, DNA-based tests for differentiation of Theileria species and characterisation of Theileria parva stocks have been developed. These tests have been derived through physical mapping and sequencing of key elements of the T. parva genome, which include repetitive and telomeric regions, minisatellite sequences, antigen genes and a number of random DNA sequences. These tools are currently being deployed in conjunction with field immunisation programmes to determine the biological impact of introducing live vaccines of T. parva on population dynamics.
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Affiliation(s)
- S P Morzaria
- International Livestock Research Institute (ILRI), Nairobi, Kenya.
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Abstract
Molecular tools based on seminested RFLP-PCR techniques to characterize field parasites in bloodspots dried on filter paper permitted investigation of the extent and the dynamics of diversity of Theileria parva populations in the field. Parallel molecular studies explored the long-term genome stability of various isolates by probing Southern blots of EcoRI digested total genomic DNA with four different reference nucleic acid probes. Three polymorphic single copy loci encoding for antigen genes were developed for seminested PCR detection in order to apply them for a multilocus approach in population genetic studies. Seven alleles were identified for the polymorphic immunodominant molecule (PIM) locus by using restriction enzymes, and 4 alleles each for the p150 and p104 loci. A simple DNA extraction method gave good results in amplifying these loci from carrier animals using samples of blood dried on filter papers. Results from probing Southern blots of cultures taken at sequential timepoints indicate relative genome stability in T. parva in comparison to other parasitic protozoa such as Plasmodium. Comparatively homogeneous profiles in sympatric isolates from Zambia were identified using all four probes and PCR amplified products which contrasted with the variety found amongst Kenyan stocks. Preliminary characterization of T. parva field samples from the Southern Province of Zambia strongly suggest clonal expansion of one of the components of a non-Zambian trivalent vaccine used on a limited scale in the Province from 1985 until 1992.
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Affiliation(s)
- D Geysen
- Institute of Tropical Medicine, Antwerp, Belgium
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Morzaria S, Bishop R, Nene V, Skilton R, Geysen D, Mbogo S. Molecular characterisation of theileria parva populations in areas of deployment of live east coast fever vaccines. Parasitol Int 1998. [DOI: 10.1016/s1383-5769(98)80059-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Katende J, Morzaria S, Toye P, Skilton R, Nene V, Nkonge C, Musoke A. An enzyme-linked immunosorbent assay for detection of Theileria parva antibodies in cattle using a recombinant polymorphic immunodominant molecule. Parasitol Res 1998; 84:408-16. [PMID: 9610640 DOI: 10.1007/s004360050419] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Field and experimental bovine infection sera were used in immunoblots of sporozoite and schizont lysates of Theileria parva to identify candidate diagnostic antigens. Four parasite antigens of Mr 67,000 (p67), 85,000 (the polymorphic immunodominant molecule, PIM), 104,000 (p104), and 150,000 (p150) were selected for a more detailed analysis. The p67 and p104 antigens were present only in the sporozoite lysates, whereas PIM and p150 were found in both sporozoite and schizont lysates. The four antigens were expressed as recombinant fusion proteins and were compared with each other in an enzyme-linked immunosorbent assay (ELISA) and in the whole-schizont-based indirect fluorescent antibody test (IFAT) in terms of their ability to detect antibodies in sera of experimentally infected cattle. The PIM-based ELISA provided a higher degree of sensitivity and specificity than did the ELISA using the other three recombinant antigens or the IFAT. Further evaluation of the PIM-ELISA using experimental sera derived from cattle infected with different hemoparasites and field sera from endemic and nonendemic T. parva areas showed that the assay had a sensitivity of > 99% and a specificity of between 94% and 98%.
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Affiliation(s)
- J Katende
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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