1
|
Hawadak J, Kojom Foko LP, Dongang Nana RR, Yadav K, Pande V, Das A, Singh V. Genetic diversity and natural selection of apical membrane antigen-1 (ama-1) in Cameroonian Plasmodium falciparum isolates. Gene 2024; 894:147956. [PMID: 37925116 DOI: 10.1016/j.gene.2023.147956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023]
Abstract
Antigenic variation associated with genetic diversity in global Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a major impediment to designing an effective malaria vaccine. Here, we report the first study on genetic diversity and natural selection of the Pfama-1 gene in P. falciparum isolates from Cameroon. A total of 328 P. falciparum positive samples collected during 2016 and 2019 from five localities of Cameroon were analysed. The ectodomain coding fragment of Pfama-1 gene was amplified for polymorphism profiling and natural selection analysis. A total of 108 distinct haplotypes were found in 203 P. falciparum isolates with considerable nucleotide diversity (π = 0.016) and haplotype diversity (Hd = 0.976). Most amino acid substitutions detected were scattered in ectodomain-I and few specific mutations viz P145L, K148Q, K462I, L463F, N471K, S482L, E537G, K546R and I547F were seen only in Cameroonian isolates. A tendency of natural selection towards positive diversifying selection was observed (Taj-D = 2.058). Five positively selected codon sites (P145L, S283L, Q308E/K, P330S and I547F) were identified, which overlapped with predicted B-cell epitopes and red blood cell (RBC) binding sites, suggesting their potential implication in host immune pressure and parasite-RBC binding complex modulation. The Cameroonian P. falciparum populations indicated a moderate level of genetic differentiation when compared with global sequences, with few exceptions from Vietnam and Venezuela. Our findings provide baseline data on existing Pfama-1 gene polymorphisms in Cameroonian field isolates, which will be useful information for malaria vaccine design.
Collapse
Affiliation(s)
- Joseph Hawadak
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Loick Pradel Kojom Foko
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Rodrigue Roman Dongang Nana
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Institut de Recherches Médicales et D'Etudes des Plantes Médicinales (IMPM), Yaoundé, Cameroon
| | - Karmveer Yadav
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Aparup Das
- ICMR-National Institute for Research in Tribal Health (NIRTH), Jabalpur, India.
| | - Vineeta Singh
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India.
| |
Collapse
|
2
|
Nirmolia T, Ahmed MA, Sathishkumar V, Sarma NP, Bhattacharyya DR, Mohapatra PK, Bansal D, Bharti PK, Sehgal R, Mahanta J, Sultan AA, Narain K, Patgiri SJ. Genetic diversity of Plasmodium falciparum AMA-1 antigen from the Northeast Indian state of Tripura and comparison with global sequences: implications for vaccine development. Malar J 2022; 21:62. [PMID: 35193607 PMCID: PMC8861999 DOI: 10.1186/s12936-022-04081-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 02/07/2022] [Indexed: 11/18/2022] Open
Abstract
Background Malaria continues to be a major public health problem in the Northeastern part of India despite the implementation of vector control measures and changes in drug policies. To develop successful vaccines against malaria, it is important to assess the diversity of vaccine candidate antigens in field isolates. This study was done to assess the diversity of Plasmodium falciparum AMA-1 vaccine candidate antigen in a malaria-endemic region of Tripura in Northeast India and compare it with previously reported global isolates with a view to assess the feasibility of developing a universal vaccine based on this antigen. Methods Patients with fever and malaria-like illness were screened for malaria and P. falciparum positive cases were recruited for the current study. The diversity of PfAMA-1 vaccine candidate antigen was evaluated by nested PCR and RFLP. A selected number of samples were sequenced using the Sanger technique. Results Among 56 P. falciparum positive isolates, Pfama-1 was successfully amplified in 75% (n = 42) isolates. Allele frequencies of PfAMA-1 antigen were 16.6% (n = 7) for 3D7 allele and 33.3% (n = 14) in both K1 and HB3 alleles. DNA sequencing revealed 13 haplotypes in the Pfama-1 gene including three unique haplotypes not reported earlier. No unique amino-acid substitutions were found. Global analysis with 2761 sequences revealed 435 haplotypes with a very complex network composition and few clusters. Nucleotide diversity for Tripura (0.02582 ± 0.00160) showed concordance with South-East Asian isolates while recombination parameter (Rm = 8) was lower than previous reports from India. Population genetic structure showed moderate differentiation. Conclusions Besides documenting all previously reported allelic forms of the vaccine candidate PfAMA-1 antigen of P. falciparum, new haplotypes not reported earlier, were found in Tripura. Neutrality tests indicate that the Pfama-1 population in Tripura is under balancing selection. This is consistent with global patterns. However, the high haplotype diversity observed in the global Pfama-1 network analysis indicates that designing a universal vaccine based on this antigen may be difficult. This information adds to the existing database of genetic diversity of field isolates of P. falciparum and may be helpful in the development of more effective vaccines against the parasite. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04081-1.
Collapse
Affiliation(s)
- Tulika Nirmolia
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Md Atique Ahmed
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Vinayagam Sathishkumar
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Nilanju P Sarma
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India.,SRL Reference Laboratory, Mumbai, 400060, India
| | - Dibya R Bhattacharyya
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Pradyumna K Mohapatra
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Devendra Bansal
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Doha, Qatar.,Ministry of Public Health, Doha, Qatar
| | - Praveen K Bharti
- ICMR - National Institute for Research in Tribal Health, Jabalpur, Madhya Pradesh, 482003, India
| | - Rakesh Sehgal
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, Punjab, 160012, India
| | - Jagadish Mahanta
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Ali A Sultan
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Doha, Qatar
| | - Kanwar Narain
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India
| | - Saurav J Patgiri
- ICMR - Regional Medical Research Centre, North East Region, Dibrugarh, Assam, 786001, India.
| |
Collapse
|
3
|
Genetic Polymorphism and Natural Selection of Apical Membrane Antigen-1 in Plasmodium falciparum Isolates from Vietnam. Genes (Basel) 2021; 12:genes12121903. [PMID: 34946853 PMCID: PMC8701107 DOI: 10.3390/genes12121903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/22/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Apical membrane antigen-1 of Plasmodium falciparum (PfAMA-1) is a leading malaria vaccine candidate antigen. However, the genetic diversity of pfama-1 and associated antigenic variation in global P. falciparum field isolates are major hurdles to the design of an efficacious vaccine formulated with this antigen. Here, we analyzed the genetic structure and the natural selection of pfama-1 in the P. falciparum population of Vietnam. A total of 37 distinct haplotypes were found in 131 P. falciparum Vietnamese isolates. Most amino acid changes detected in Vietnamese pfama-1 were localized in the ectodomain, domains I, II, and III. Overall patterns of major amino acid changes in Vietnamese pfama-1 were similar to those of global pfama-1, but the frequencies of the amino acid changes slightly differed by country. Novel amino acid changes were also identified in Vietnamese pfama-1. Vietnamese pfama-1 revealed relatively lower genetic diversity than currently analyzed pfama-1 in other geographical regions, and suggested a distinct genetic differentiation pattern. Evidence for natural selection was detected in Vietnamese pfama-1, but it showed purifying selection unlike the global pfama-1 analyzed so far. Recombination events were also found in Vietnamese pfama-1. Major amino acid changes that were commonly identified in global pfama-1 were mainly localized to predicted B-cell epitopes, RBC-binding sites, and IUR regions. These results provide important information for understanding the genetic nature of the Vietnamese pfama-1 population, and have significant implications for the design of a vaccine based on PfAMA-1.
Collapse
|
4
|
Genetic diversity and expression profile of Plasmodium falciparum Pf34 gene supports its immunogenicity. Curr Res Transl Med 2021; 69:103308. [PMID: 34425378 DOI: 10.1016/j.retram.2021.103308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/02/2021] [Accepted: 08/06/2021] [Indexed: 11/22/2022]
Abstract
PURPOSE OF THE STUDY Genetic variation is one of the major obstacles in the development of effective vaccines. A multivalent malaria vaccine is required to increase efficacy and confer long term protection. In this context, we analysed the genetic diversity, expression profile, and immune response against Pf34. METHODS Phylogenetic analysis was carried out using Pf34 orthologues sequences of various Plasmodium species. Genetic diversity was analysed by PCR amplification and Sanger dideoxy sequencing of Pf34 gene from Plasmodium falciparum positive human blood samples. The expression level of Pf34 gene was studied during erythrocytic stage by real time qPCR at four-hour interval, and immune response against synthetic peptides of Pf34 (P1 and P2) was analysed using ELISA. RESULTS Phylogenetic analysis revealed the conserved nature of Pf34 gene. Genetic diversity analysis showed that majority (92%) of Plasmodium falciparum isolates in available database bore wild type Pf34 gene (Hd = 0.160 ± 0.030, π = 0.00021), including the present study (89.3%). The P. falciparum specific amino acid repeats (NNDK, NNDLK, and NNNNNN) in the B cell epitope regions were conserved. Furthermore, Pf34 gene is expressed throughout the erythrocytic cycle and comparatively high expression was observed in early ring and schizont stage. High IgG response was observed against both the peptides P1 and P2 of Pf34 containing asparagine NNNNNN and NNDLK repeat respectively. CONCLUSION The limited genetic diversity, presence of conserved amino acid repeats within B cell epitope and high IgG response suggests that Pf34 may be a potential vaccine candidate for malaria. However, further validation studies are required.
Collapse
|
5
|
Huang F, Jacob CG, Takala-Harrison S, Adams M, Yang HL, Liu H, Xia ZG, Zhou SS, Tang LH, Plowe CV. Genomic Epidemiology of Antimalarial Drug Resistance in Plasmodium falciparum in Southern China. Front Cell Infect Microbiol 2021; 10:610985. [PMID: 33489939 PMCID: PMC7820777 DOI: 10.3389/fcimb.2020.610985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/20/2020] [Indexed: 12/05/2022] Open
Abstract
Emerging artemisinin resistance in Southeast Asia poses a significant risk to malaria control and eradication goals, including China’s plan to eliminate malaria nationwide by 2020. Plasmodium falciparum was endemic in China, especially in Southern China. Parasites from this region have shown decreased susceptibility to artemisinin and delayed parasite clearance after artemisinin treatment. Understanding the genetic basis of artemisinin resistance and identifying specific genetic loci associated with this phenotype is crucial for surveillance and containment of resistance. In this study, parasites were collected from clinical patients from Yunnan province and Hainan island. The parasites were genotyped using a P. falciparum-specific single nucleotide polymorphism (SNP) microarray. The SNP profiles examined included a total of 27 validated and candidate molecular markers of drug resistance. The structure of the parasite population was evaluated by principal component analysis by using the EIGENSOFT program, and ADMIXTURE was used to calculate maximum likelihood estimates for the substructure analysis. Parasites showed a high prevalence of resistance haplotypes of pfdhfr and pfdhps and moderate prevalence of pfcrt. There was no mutation identified on pfmdr1. Candidate SNPs on chromosomes 10, 13, and 14 that were associated with delayed parasite clearance showed a low prevalence of mutants. Parasites from Southern China were clustered and separated from those from Southeast Asia. Parasites from Yunnan province were substructured from parasites from Hainan island. This study provides evidence for a genomic population with drug resistance in Southern China and also illustrates the utility of SNP microarrays for large-scale parasite molecular epidemiology.
Collapse
Affiliation(s)
- Fang Huang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | | | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Heng-Lin Yang
- Malaria Department, Yunnan Institute of Parasitic Diseases, Puer, China
| | - Hui Liu
- Malaria Department, Yunnan Institute of Parasitic Diseases, Puer, China
| | - Zhi-Gui Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Shui-Sen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | - Lin-Hua Tang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, Ministry of Health, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, China
| | | |
Collapse
|
6
|
Torrevillas BK, Garrison SM, McKeeken AJ, Patel D, Van Leuven JT, Dizon NI, Rivas KI, Hathaway NJ, Bailey JA, Waitumbi JN, Kifude CM, Oyieko J, Stewart VA, Luckhart S. Plasmodium falciparum DHFR and DHPS Mutations Are Associated With HIV-1 Co-Infection and a Novel DHPS Mutation I504T Is Identified in Western Kenya. Front Cell Infect Microbiol 2020; 10:600112. [PMID: 33324580 PMCID: PMC7725689 DOI: 10.3389/fcimb.2020.600112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/28/2020] [Indexed: 11/13/2022] Open
Abstract
Antifolate resistance is significant in Kenya and presumed to result from extensive use and cross-resistance between antifolate antimalarials and antibiotics, including cotrimoxazole/Bactrim used for HIV-1 chemotherapy. However, little is known about antifolate-resistant malaria in the context of newly diagnosed HIV-1 co-infection prior to administration of HIV-1 chemotherapy. Blood samples from a cross-sectional study of asymptomatic adult Kenyans enrolled during voluntary HIV testing were analyzed by PCR for Plasmodium spp. More than 95% of volunteers with identifiable parasite species (132 HIV-1 co-infected) were infected with Plasmodium falciparum alone or P. falciparum with Plasmodium ovale and/or Plasmodium malariae. Deep sequencing was used to screen for mutations in P. falciparum dihydrofolate reductase (dhfr) (N51I, C59R, S108N, I164L) and dihydropteroate synthase (dhps) (S436H, A437G, K540E, A581G) from 1133 volunteers. Individual mutations in DHPS but not DHFR correlated with HIV-1 status. DHFR haplotype diversity was significantly different among volunteers by gender and HIV-1 status. DHPS haplotype diversity by HIV-1 status was significantly different between volunteers paired by age and gender, indicating that patterns of resistance were independent of these variables. Molecular simulations for a novel DHPS mutation (I504T) suggested that the mutated protein has increased affinity for the endogenous ligand DHPPP and decreased affinity for drug binding. A sub-group of monoclonal infections revealed that age and parasitemia were not correlated and enabled identification of a rare septuple-mutant haplotype (IRNL-HGEA). In our study, adult Kenyans newly diagnosed with HIV-1 infection were predominantly infected with moderately resistant P. falciparum, with patterns of infecting parasite genotypes significantly associated with HIV-1 status. Together with the discovery of DHPS I504T, these data indicate that antifolate resistance continues to evolve in Kenya. Further, they highlight the need to understand the effects of associated mutations on both fitness and resistance of P. falciparum in the context of HIV-1 co-infection to better inform treatment for asymptomatic malaria.
Collapse
Affiliation(s)
- Brandi K Torrevillas
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Sarah M Garrison
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Alexander J McKeeken
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Dharmeshkumar Patel
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID, United States
| | - James T Van Leuven
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID, United States.,Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Nathaniel I Dizon
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Karina I Rivas
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, MA, United States
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - John N Waitumbi
- Basic Science Laboratory, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute, Kisumu, Kenya
| | - Carolyne M Kifude
- Basic Science Laboratory, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute, Kisumu, Kenya
| | - Janet Oyieko
- Basic Science Laboratory, United States Army Medical Research Directorate-Africa, Kenya Medical Research Institute, Kisumu, Kenya
| | - V Ann Stewart
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States.,Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| |
Collapse
|
7
|
Wang YN, Lin M, Liang XY, Chen JT, Xie DD, Wang YL, Ehapo CS, Eyi UM, Huang HY, Wu JL, Xu DY, Chen ZM, Cao YL, Chen HB. Natural selection and genetic diversity of domain I of Plasmodium falciparum apical membrane antigen-1 on Bioko Island. Malar J 2019; 18:317. [PMID: 31533747 PMCID: PMC6751645 DOI: 10.1186/s12936-019-2948-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/06/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a promising candidate antigen for a blood-stage malaria vaccine. However, antigenic variation and diversity of PfAMA-1 are still major problems to design a universal malaria vaccine based on this antigen, especially against domain I (DI). Detail understanding of the PfAMA-1 gene polymorphism can provide useful information on this potential vaccine component. Here, general characteristics of genetic structure and the effect of natural selection of DIs among Bioko P. falciparum isolates were analysed. METHODS 214 blood samples were collected from Bioko Island patients with P. falciparum malaria between 2011 and 2017. A fragment spanning DI of PfAMA-1 was amplified by nested polymerase chain reaction and sequenced. Polymorphic characteristics and the effect of natural selection were analysed using MEGA 5.0, DnaSP 6.0 and Popart programs. Genetic diversity in 576 global PfAMA-1 DIs were also analysed. Protein function prediction of new amino acid mutation sites was performed using PolyPhen-2 program. RESULTS 131 different haplotypes of PfAMA-1 were identified in 214 Bioko Island P. falciparum isolates. Most amino acid changes identified on Bioko Island were found in C1L. 32 amino acid changes identified in PfAMA-1 sequences from Bioko Island were found in predicted RBC-binding sites, B cell epitopes or IUR regions. Overall patterns of amino acid changes of Bioko PfAMA-1 DIs were similar to those in global PfAMA-1 isolates. Differential amino acid substitution frequencies were observed for samples from different geographical regions. Eight new amino acid changes of Bioko island isolates were also identified and their three-dimensional protein structural consequences were predicted. Evidence for natural selection and recombination event were observed in global isolates. CONCLUSIONS Patterns of nucleotide diversity and amino acid polymorphisms of Bioko Island isolates were similar to those of global PfAMA-1 DIs. Balancing natural selection across DIs might play a major role in generating genetic diversity in global isolates. Most amino acid changes in DIs occurred in predicted B-cell epitopes. Novel sites mapped on a three dimensional structure of PfAMA-1 showed that these regions were located at the corner. These results may provide significant value in the design of a malaria vaccine based on this antigen.
Collapse
Affiliation(s)
- Ya-Nan Wang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Min Lin
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Xue-Yan Liang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jiang-Tao Chen
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong, People's Republic of China
| | - Dong-De Xie
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Yu-Ling Wang
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Carlos Salas Ehapo
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Urbano Monsuy Eyi
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Hui-Ying Huang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jing-Li Wu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Dan-Yan Xu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Zhi-Mao Chen
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Yi-Long Cao
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Hai-Bin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China.
| |
Collapse
|
8
|
Shen HM, Chen SB, Cui YB, Xu B, Kassegne K, Abe EM, Wang Y, Chen JH. Whole-genome sequencing and analysis of Plasmodium falciparum isolates from China-Myanmar border area. Infect Dis Poverty 2018; 7:118. [PMID: 30445995 PMCID: PMC6240207 DOI: 10.1186/s40249-018-0493-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/16/2018] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND China has made progress in malaria control and aims to eliminate malaria nationwide, but implementing effective interventions along the border regions remain a huge task. The Plasmodium falciparum cases imported from Southeast Asia has frequently reported especially in the China-Myanmar border (CMB) area. Though, information is scant on P. falciparum genetic variability in this area. METHODS This study reported P. falciparum isolates genome sequence of six clinical isolates in the CMB area. Furthermore, we estimated the nucleotide diversity, Watterson's estimator and Tajima's D value for the whole genome mutation rate in slide window. RESULTS Our data were aligned onto 96.05-98.61% of the reference 3D7 genome in high fold coverages. Principal component analysis result showed that P. falciparum clustered generally according to their geographic origin. A total of 91 genes were identified as positive selection with Ka/Ks ratio significantly higher than 1, and most of them were multigene families encoding variant surface antigens (VSAs) such as var, rif and stevor. The enrichment of the positive selection on VSA genes implied that the environment complexity subjected CMB's P. falciparum to more pressure for survival. CONCLUSIONS Our research suggests that greater genetic diversity in CMB area and the positive selection signals in VSA genes, which allow P. falciparum to fit the host immune system well and aggravate the difficulty of treatment. Meanwhile, results obtained from this study will provide the fundamental basis for P. falciparum population genomic research in CMB area.
Collapse
Affiliation(s)
- Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Yan-Bing Cui
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Bin Xu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Kokouvi Kassegne
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Eniola Michael Abe
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| | - Yue Wang
- Institute of Parasitic Diseases, Zhejiang Academy of Medical Sciences, Hangzhou, 310013 China
- Department of Microbiology and Microbial Engineering, School of Life Science, Fudan University, Shanghai, 200433 China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025 China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025 China
| |
Collapse
|
9
|
Lumkul L, Sawaswong V, Simpalipan P, Kaewthamasorn M, Harnyuttanakorn P, Pattaradilokrat S. Unraveling Haplotype Diversity of the Apical Membrane Antigen-1 Gene in Plasmodium falciparum Populations in Thailand. THE KOREAN JOURNAL OF PARASITOLOGY 2018; 56:153-165. [PMID: 29742870 PMCID: PMC5976018 DOI: 10.3347/kjp.2018.56.2.153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/14/2018] [Accepted: 04/05/2018] [Indexed: 12/20/2022]
Abstract
Development of an effective vaccine is critically needed for the prevention of malaria. One of the key antigens for malaria vaccines is the apical membrane antigen 1 (AMA-1) of the human malaria parasite Plasmodium falciparum, the surface protein for erythrocyte invasion of the parasite. The gene encoding AMA-1 has been sequenced from populations of P. falciparum worldwide, but the haplotype diversity of the gene in P. falciparum populations in the Greater Mekong Subregion (GMS), including Thailand, remains to be characterized. In the present study, the AMA-1 gene was PCR amplified and sequenced from the genomic DNA of 65 P. falciparum isolates from 5 endemic areas in Thailand. The nearly full-length 1,848 nucleotide sequence of AMA-1 was subjected to molecular analyses, including nucleotide sequence diversity, haplotype diversity and deduced amino acid sequence diversity and neutrality tests. Phylogenetic analysis and pairwise population differentiation (Fst indices) were performed to infer the population structure. The analyses identified 60 single nucleotide polymorphic loci, predominately located in domain I of AMA-1. A total of 31 unique AMA-1 haplotypes were identified, which included 11 novel ones. The phylogenetic tree of the AMA-1 haplotypes revealed multiple clades of AMA-1, each of which contained parasites of multiple geographical origins, consistent with the Fst indices indicating genetic homogeneity or gene flow among geographically distinct populations of P. falciparum in Thailand’s borders with Myanmar, Laos and Cambodia. In summary, the study revealed novel haplotypes and population structure needed for the further advancement of AMA-1-based malaria vaccines in the GMS.
Collapse
Affiliation(s)
- Lalita Lumkul
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Vorthon Sawaswong
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Phumin Simpalipan
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Morakot Kaewthamasorn
- Veterinary Parasitology Research Group, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | | | - Sittiporn Pattaradilokrat
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.,Veterinary Parasitology Research Group, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| |
Collapse
|
10
|
Kang JM, Lee J, Moe M, Jun H, Lê HG, Kim TI, Thái TL, Sohn WM, Myint MK, Lin K, Shin HJ, Kim TS, Na BK. Population genetic structure and natural selection of Plasmodium falciparum apical membrane antigen-1 in Myanmar isolates. Malar J 2018; 17:71. [PMID: 29415731 PMCID: PMC5804060 DOI: 10.1186/s12936-018-2215-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is one of leading blood stage malaria vaccine candidates. However, genetic variation and antigenic diversity identified in global PfAMA-1 are major hurdles in the development of an effective vaccine based on this antigen. In this study, genetic structure and the effect of natural selection of PfAMA-1 among Myanmar P. falciparum isolates were analysed. Methods Blood samples were collected from 58 Myanmar patients with falciparum malaria. Full-length PfAMA-1 gene was amplified by polymerase chain reaction and cloned into a TA cloning vector. PfAMA-1 sequence of each isolate was sequenced. Polymorphic characteristics and effect of natural selection were analysed with using DNASTAR, MEGA4, and DnaSP programs. Polymorphic nature and natural selection in 459 global PfAMA-1 were also analysed. Results Thirty-seven different haplotypes of PfAMA-1 were identified in 58 Myanmar P. falciparum isolates. Most amino acid changes identified in Myanmar PfAMA-1 were found in domains I and III. Overall patterns of amino acid changes in Myanmar PfAMA-1 were similar to those in global PfAMA-1. However, frequencies of amino acid changes differed by country. Novel amino acid changes in Myanmar PfAMA-1 were also identified. Evidences for natural selection and recombination event were observed in global PfAMA-1. Among 51 commonly identified amino acid changes in global PfAMA-1 sequences, 43 were found in predicted RBC-binding sites, B-cell epitopes, or IUR regions. Conclusions Myanmar PfAMA-1 showed similar patterns of nucleotide diversity and amino acid polymorphisms compared to those of global PfAMA-1. Balancing natural selection and intragenic recombination across PfAMA-1 are likely to play major roles in generating genetic diversity in global PfAMA-1. Most common amino acid changes in global PfAMA-1 were located in predicted B-cell epitopes where high levels of nucleotide diversity and balancing natural selection were found. These results highlight the strong selective pressure of host immunity on the PfAMA-1 gene. These results have significant implications in understanding the nature of Myanmar PfAMA-1 along with global PfAMA-1. They also provide useful information for the development of effective malaria vaccine based on this antigen.
Collapse
Affiliation(s)
- Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jinyoung Lee
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, 54538, Republic of Korea
| | - Mya Moe
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Hojong Jun
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Tae Im Kim
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,Planning and Management Division, Nakdonggang National Institute of Biological Resources, Sangju, 37242, Republic of Korea
| | - Thị Lam Thái
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Lin
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University College of Medicine, Suwon, 16499, Republic of Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
| |
Collapse
|
11
|
Rittipornlertrak A, Nambooppha B, Simking P, Punyapornwithaya V, Tiwananthagorn S, Jittapalapong S, Chung YT, 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. INFECTION GENETICS AND EVOLUTION 2017; 54:447-454. [PMID: 28807856 DOI: 10.1016/j.meegid.2017.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/08/2017] [Accepted: 08/10/2017] [Indexed: 10/19/2022]
Abstract
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.
Collapse
Affiliation(s)
| | | | - Pacharathon Simking
- Faculty of Agricultural Technology, Rajamangala University of Technology Thanyaburi, Pathumthani 12110, Thailand
| | | | | | | | - Yang-Tsung Chung
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan
| | - Nattawooti Sthitmatee
- Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Excellent Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai 50100, Thailand.
| |
Collapse
|
12
|
Zhao Y, Zhao Y, Lv Y, Liu F, Wang Q, Li P, Zhao Z, Liu Y, Cui L, Fan Q, Cao Y. Comparison of methods for detecting asymptomatic malaria infections in the China-Myanmar border area. Malar J 2017; 16:159. [PMID: 28427455 PMCID: PMC5397696 DOI: 10.1186/s12936-017-1813-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/09/2017] [Indexed: 02/06/2023] Open
Abstract
Background Sensitive methods for detecting asymptomatic malaria infections are essential for identifying potential transmission reservoirs and obtaining an accurate assessment of malaria epidemiology in low-endemicity areas aiming to eliminate malaria. PCR techniques to detect parasite nucleic acids (DNA or RNA) are among the most commonly used molecular methods. However, most of these methods are of low throughput and cannot be used for large-scale molecular epidemiological studies. A recently developed capture and ligation probe-PCR (CLIP-PCR) is claimed to have the sensitivity of molecular techniques and the high throughput capacity needed for screening purposes. This study aimed to compare several molecular methods for detecting asymptomatic and submicroscopic Plasmodium infections in healthy residents of a malaria-hypoendemic region in Southeast Asia, where malaria elimination is in sight. Method This study compared three molecular detection methods side-by-side, namely nested PCR targeting the rRNA genes, nested RT-PCR to detect parasite rRNA, and CLIP-PCR to detect parasite rRNA in 1005 healthy individuals in northeastern Myanmar. For nested PCR and RT-PCR, parasite DNA and total RNA were extracted from ~100 µL of blood, whereas RNA used for CLIP-PCR was from a 3 mm disk of dried blood filter paper. The sensitivity and specificity of these methods were compared with those of conventional light microscopy. In addition, RT-PCR and quantitative RT-PCR (qRT-PCR) targeting the Pvs25 gene in Plasmodium vivax were used to assess gametocyte prevalence in the samples. Results Light microscopy detected Plasmodium infections in only 1.19% of the residents harbouring the parasites. CLIP-PCR had slightly better performance and detected Plasmodium infections in 1.89% of the population. Further improvement was achieved by nested PCR to detect parasite DNA, which detected P. vivax and Plasmodium falciparum infections in 2.39% of the residents. The nested RT-PCR targeting rRNA, however, detected as many as 187 (18.61%) individuals having Plasmodium infections with P. vivax being the predominant species (176 P. vivax, 5 P. falciparum and 6 P. falciparum/P. vivax mixed infections). Of the 210 Plasmodium-positive samples detected by all molecular methods, 115 were Pvs25-positive by qRT-PCR, indicating that a large proportion of asymptomatic individuals were gametocyte carriers. Conclusion Nested RT-PCR based on the detection of asexual-stage parasite rRNA was the most sensitive, with a more than sixfold higher sensitivity than the other two molecular methods of parasite detection. CLIP-PCR has an increased throughput, but its sensitivity in this study was much lower than those of other molecular methods, which may be partially due to the smaller amount of RNA input used. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1813-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yonghong Zhao
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Yan Zhao
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Yanmin Lv
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Fei Liu
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, China Medical University, Shenyang, Liaoning, China
| | - Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yingjie Liu
- Department of Pathogen Biology, China Medical University, Shenyang, Liaoning, China
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, USA.
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China.
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, Liaoning, China.
| |
Collapse
|
13
|
Zhu X, Zhao P, Wang S, Liu F, Liu J, Wang J, Yang Z, Yan G, Fan Q, Cao Y, Cui L. Analysis of Pvama1 genes from China-Myanmar border reveals little regional genetic differentiation of Plasmodium vivax populations. Parasit Vectors 2016; 9:614. [PMID: 27899135 PMCID: PMC5129220 DOI: 10.1186/s13071-016-1899-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 11/21/2016] [Indexed: 12/22/2022] Open
Abstract
Background With the premise of diminishing parasite genetic diversity following the reduction of malaria incidence, the analysis of polymorphic antigenic markers may provide important information about the impact of malaria control on local parasite populations. Here we evaluated the genetic diversity of Plasmodium vivax apical membrane antigen 1 (Pvama1) gene in a parasite population from the China-Myanmar border and compared it with global P. vivax populations. Methods We performed evolutionary analysis to examine the genetic diversity, natural selection, and population differentiation of 73 Pvama1 sequences acquired from the China-Myanmar border as well as 615 publically available Pvama1 sequences from seven global P. vivax populations. Results A total of 308 Pvama1 haplotypes were identified among the global P. vivax isolates. The overall nucleotide diversity of Pvama1 gene among the 73 China-Myanmar border parasite isolates was 0.008 with 41 haplotypes being identified (Hd = 0.958). Domain I (DI) harbored the majority (26/33) of the polymorphic sites. The McDonald Kreitman test showed a significant positive selection across the ectodomain and the DI of Pvama1. The fixation index (FST) estimation between the China-Myanmar border, Thailand (0.01) and Myanmar (0.10) showed only slight geographical genetic differentiation. Notably, the Sal-I haplotype was not detected in any of the analyzed global isolates, whereas the Belem strain was restricted to the Thai population. The detected mutations are mapped outside the overlapped region of the predicted B-cell epitopes and intrinsically unstructured/disordered regions. Conclusions This study revealed high levels of genetic diversity of Pvama1 in the P. vivax parasite population from the China-Myanmar border with DI displaying stronger diversifying selection than other domains. There were low levels of population subdivision among parasite populations from the Greater Mekong Subregion. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1899-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Pan Zhao
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Si Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Jun Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China
| | - Jian Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning, 110122, China. .,Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|