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Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks
Dissertation (MSc (Biochemistry))--University of Pretoria, 2015.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2016
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| _version_ | 1867613507225124864 |
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| access_status_str | Open Access |
| author2 | Maritz-Olivier, Christine |
| author_browse | Maritz-Olivier, Christine |
| author_facet | Maritz-Olivier, Christine |
| collection | Thesis |
| dc_rights_str_mv | © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Biochemistry))--University of Pretoria, 2015. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/51913 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:14.671Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/51913 Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks Maritz-Olivier, Christine Van Wyk, Roelof UCTD Dissertation (MSc (Biochemistry))--University of Pretoria, 2015. Rhipicephalus microplus is a tick with a one-host life cycle which takes place on cattle. It has three life stages during the host phase. Tropical and sub-tropical regions around the world make for an ideal climate for both R. microplus and R. decoloratus ticks. Both tick species are well documented as vectors for various tick-borne diseases. Several target site resistance markers are known for acaricide resistance in R. microplus and the presence of these markers in R. decoloratus is a focus of this study. The dieldrin resistance marker was not observed in R. decoloratus nor was the pyrethroid resistance marker in the carboxylesterase gene. The octopamine/tyramine receptor showed the presence of 49 different SNPs as compared to with the NCBI R. microplus entry (AJ010743.1). Maximum parsimony tree analysis of this gene segment which included locally sequenced R. decoloratus and R. microplus tick samples showed a mix grouping of both species. This would suggest that there is not a significant difference between R. decoloratus and R. microplus for the octopamine/tyramine receptor to group them as separate. Analysis of the voltage-gated sodium channel revealed the presence of the resistance marker (L64I) in both R. microplus and R. decoloratus ticks of South Africa. Rhipicephalus microplus showed allele frequencies of 58.8% homozygous resistant and a 32.4% homozygous susceptible, while R. decoloratus had a 72% heterozygous frequency. A model for the R. microplus carboxylesterase (RmCaE) was constructed using 4B0O as a template (32.2% identity). The model was well within the expected quality range for carboxylesterase enzymes. Docking of cypermethrin showed that no direct interactions were possible between the resistance SNP site and cypermethrin, but the loss of a stabilising interaction in the secondary structure could be the main cause behind resistance. A partial model for the voltage-gated sodium channel (RmvNaCh) was constructed using 4DXW as a template (30% identity). Docking of the different stereoisomers for cypermethrin identified two key atoms (C4 and Cl-) of cypermethrin as interacting partners with the SNP site. Cyp5 was also identified as the one stereoisomer which didn’t show a difference between WT and mutant docked poses and was still capable of interacting with the SNP site. This may show cyp5 [(R)-cyano (1S, 3S)] as an important stereoisomer for use on pyrethroid resistance R. microplus ticks. Experimental validation of in silico results must be done in future. tm2015 Biochemistry MSc (Biochemistry) 2016-04-08T07:24:56Z 2016-04-08T07:24:56Z 2015 Dissertation * A2016 http://hdl.handle.net/2263/51913 en © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title | Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title_full | Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title_fullStr | Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title_full_unstemmed | Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title_short | Mutation status and homology modelling of acaricide-binding proteins in Rhipicephalus ticks |
| title_sort | mutation status and homology modelling of acaricide binding proteins in rhipicephalus ticks |
| topic | UCTD |
| url | http://hdl.handle.net/2263/51913 |