Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand

© 2017 Elsevier B.V. Babesia bovis, a parasite infecting cattle and buffalo, continues to spread throughout the developing world. The babesial vaccine was developed to be a sustainable alternative treatment to control the parasite. However, genetic diversity is a major obstacle for designing and dev...

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Main Authors: Rittipornlertrak A., Nambooppha B., Simking P., Punyapornwithaya V., Tiwananthagorn S., Jittapalapong S., Chung Y., Sthitmatee N.
Format: Journal
Published: 2017
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http://cmuir.cmu.ac.th/jspui/handle/6653943832/40101
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spelling th-cmuir.6653943832-401012017-09-28T04:05:18Z Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand Rittipornlertrak A. Nambooppha B. Simking P. Punyapornwithaya V. Tiwananthagorn S. Jittapalapong S. Chung Y. Sthitmatee N. © 2017 Elsevier B.V. Babesia bovis, a parasite infecting cattle and buffalo, continues to spread throughout the developing world. The babesial vaccine was developed to be a sustainable alternative treatment to control the parasite. However, genetic diversity is a major obstacle for designing and developing a safe and effective vaccine. The apical membrane antigen 1 (AMA-1) is considered to be a potential vaccine candidate antigen among immunogenic genes of B. bovis. To gain a more comprehensive understanding of B. bovis AMA-1 (BbAMA-1), three B. bovis DNA samples were randomly selected to characterize in order to explore genetic diversity and natural selection and to predict the antigen epitopes. The sequence analysis revealed that BbAMA-1 has a low level of polymorphism and is highly conserved (95.46–99.94%) among Thai and global isolates. The majority of the polymorphic sites were observed in domains I and III. Conversely, domain II contained no polymorphic sites. We report the first evidence of strong negative or purifying selection across the full length of the gene, especially in domain I, by demonstrating a significant excess of the average number of synonymous (dS) over the non-synonymous (dN) substitutions. Finally, we also predict the linear and conformational B-cell epitope. The predicted B-cell epitopes appeared to be involved with the amino acid changes. Collectively, the results suggest that the conserved BbAMA-1 may be used to detect regional differences in the B. bovis parasite. Importantly, the limitation of BbAMA-1 diversity under strong negative selection indicates strong functional constraints on this gene. Thus, the gene could be a valuable target vaccine candidate antigen. 2017-09-28T04:05:18Z 2017-09-28T04:05:18Z Journal 15671348 2-s2.0-85028350875 10.1016/j.meegid.2017.08.009 https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85028350875&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/40101
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
description © 2017 Elsevier B.V. Babesia bovis, a parasite infecting cattle and buffalo, continues to spread throughout the developing world. The babesial vaccine was developed to be a sustainable alternative treatment to control the parasite. However, genetic diversity is a major obstacle for designing and developing a safe and effective vaccine. The apical membrane antigen 1 (AMA-1) is considered to be a potential vaccine candidate antigen among immunogenic genes of B. bovis. To gain a more comprehensive understanding of B. bovis AMA-1 (BbAMA-1), three B. bovis DNA samples were randomly selected to characterize in order to explore genetic diversity and natural selection and to predict the antigen epitopes. The sequence analysis revealed that BbAMA-1 has a low level of polymorphism and is highly conserved (95.46–99.94%) among Thai and global isolates. The majority of the polymorphic sites were observed in domains I and III. Conversely, domain II contained no polymorphic sites. We report the first evidence of strong negative or purifying selection across the full length of the gene, especially in domain I, by demonstrating a significant excess of the average number of synonymous (dS) over the non-synonymous (dN) substitutions. Finally, we also predict the linear and conformational B-cell epitope. The predicted B-cell epitopes appeared to be involved with the amino acid changes. Collectively, the results suggest that the conserved BbAMA-1 may be used to detect regional differences in the B. bovis parasite. Importantly, the limitation of BbAMA-1 diversity under strong negative selection indicates strong functional constraints on this gene. Thus, the gene could be a valuable target vaccine candidate antigen.
format Journal
author Rittipornlertrak A.
Nambooppha B.
Simking P.
Punyapornwithaya V.
Tiwananthagorn S.
Jittapalapong S.
Chung Y.
Sthitmatee N.
spellingShingle Rittipornlertrak A.
Nambooppha B.
Simking P.
Punyapornwithaya V.
Tiwananthagorn S.
Jittapalapong S.
Chung Y.
Sthitmatee N.
Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
author_facet Rittipornlertrak A.
Nambooppha B.
Simking P.
Punyapornwithaya V.
Tiwananthagorn S.
Jittapalapong S.
Chung Y.
Sthitmatee N.
author_sort Rittipornlertrak A.
title Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
title_short Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
title_full Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
title_fullStr Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
title_full_unstemmed Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand
title_sort low levels of genetic diversity associated with evidence of negative selection on the babesia bovis apical membrane antigen 1 from parasite populations in thailand
publishDate 2017
url https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85028350875&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/40101
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