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Oyedeji SI, Bassi PU, Oyedeji SA, Ojurongbe O, Awobode HO. Genetic diversity and complexity of Plasmodium falciparum infections in the microenvironment among siblings of the same household in North-Central Nigeria. Malar J 2020; 19:338. [PMID: 32938438 PMCID: PMC7493857 DOI: 10.1186/s12936-020-03415-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 05/19/2020] [Accepted: 09/10/2020] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum parasites are known to exhibit extensive genetic diversity in areas of high transmission intensity and infected individuals in such communities often harbour several complex mixtures of parasite clones with different genetic characteristics. However, in the micro-environment, the extent of genetic diversity of P. falciparum parasites remain largely unknown. In this study therefore, the complexity of P. falciparum infections in households was investigated among symptomatic siblings, living under the same roof in north-central Nigeria. Methods Children were enrolled into the study if they were at least two from a household and presented with symptoms of uncomplicated malaria. Clinical malaria was confirmed by light microscopy of Giemsa-stained thick and thin blood films. Genomic DNA was isolated from blood spots on filter paper. Molecular characterization of P. falciparum isolates was done by allele-specific nested PCR of the highly polymorphic merozoite surface protein-2 (msp-2) gene. Results Ninety-three children from 43 households were enrolled into this study. A total of 26 different msp-2 alleles were identified from 215 fragments (range: 180–480 bp). Majority of the isolates [65.6% (n = 61)] were polyclonal infections consisting of 2–6 clones and were significantly more common with the FC27 allelic family (p = 0.036). The multiplicity of infection (MOI) per household ranged from 1.0 to 4.5 while the overall MOI in the study population was 2.31. The pattern of distribution of msp-2 allele types among the households fell into two categories: households where both msp-2 allele types (FC27 and 3D7) were present; households where only one msp-2 allele type (FC27 or 3D7) was present. Majority of the households [88.4% (n = 38)], had both msp-2 allele types but they were disproportionately distributed among the children while in a few households [11.6% (n = 5)], all the children were infected with only one type of msp-2 allele. Conclusion These findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the micro-environment and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the micro-environment is an important area of focus for malaria control interventions and for evaluating intervention programmes.
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Affiliation(s)
- Segun Isaac Oyedeji
- Molecular Genetics and Parasitology Unit, Department of Animal & Environmental Biology, Federal University Oye-Ekiti, Oye-Ekiti, Nigeria.
| | - Peter Usman Bassi
- Department of Pharmacology and Therapeutics, University of Abuja, Abuja, Nigeria
| | | | - Olusola Ojurongbe
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Osogbo, Nigeria
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Gresty K, Anderson K, Pasay C, Waters NC, Cheng Q. Polymorphisms in Plasmodium falciparum Kelch 13 and P. vivax Kelch 12 Genes in Parasites Collected from Three South Pacific Countries Prior to Extensive Exposure to Artemisinin Combination Therapies. Antimicrob Agents Chemother 2019; 63:e00536-19. [PMID: 31036683 DOI: 10.1128/AAC.00536-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/22/2019] [Indexed: 11/20/2022] Open
Abstract
The South Pacific countries Solomon Islands, Vanuatu, and Papua New Guinea (PNG) adopted artemisinin-based combination therapies (ACTs) in 2008. We examined Kelch 13 and Kelch 12 genes in parasites originating from these countries before or at ACT introduction. Four Kelch 13 and two Kelch 12 novel sequence polymorphisms, not associated with artemisinin resistance, were observed in parasites from Solomon Islands and Vanuatu. No polymorphisms were observed in PNG parasites. The findings provide useful baseline information.
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Hoffmann EHE, Silveira LAD, Tonhosolo R, Pereira FJT, Ribeiro WL, Tonon AP, Kawamoto F, Ferreira MU. Geographical patterns of allelic diversity in thePlasmodium falciparummalaria-vaccine candidate, merozoite surface protein-2. Annals of Tropical Medicine & Parasitology 2016. [DOI: 10.1080/00034983.2001.11813622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Congpuong K, Hoonchaiyapoom T, Inorn K. Plasmodium falciparum genotype diversity in artemisinin derivatives treatment failure patients along the Thai-Myanmar border. Korean J Parasitol 2014; 52:631-7. [PMID: 25548414 PMCID: PMC4277025 DOI: 10.3347/kjp.2014.52.6.631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [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] [Received: 03/03/2014] [Revised: 09/09/2014] [Accepted: 09/28/2014] [Indexed: 11/26/2022]
Abstract
Genetic characteristics of Plasmodium falciparum may play a role in the treatment outcome of malaria infection. We have studied the association between diversity at the merozoite surface protein-1 (msp-1), msp-2, and glutamate-rich protein (glurp) loci and the treatment outcome of uncomplicated falciparum malaria patients along the Thai-Myanmar border who were treated with artemisinin derivatives combination therapy. P. falciparum isolates were collected prior to treatment from 3 groups of patients; 50 cases of treatment failures, 50 recrudescences, and 56 successful treatments. Genotyping of the 3 polymorphic markers was analyzed by nested PCR. The distribution of msp-1 alleles was significantly different among the 3 groups of patients but not the msp-2 and glurp alleles. The allelic frequencies of K1 and MAD20 alleles of msp1 gene were higher while RO33 allele was significantly lower in the successful treatment group. Treatment failure samples had a higher median number of alleles as compared to the successful treatment group. Specific genotypes of msp-1, msp-2, and glurp were significantly associated with the treatment outcomes. Three allelic size variants were significantly higher among the isolates from the treatment failure groups, i.e., K1270-290, 3D7610-630, G650-690, while 2 variants, K1150-170, and 3D7670-690 were significantly lower. In conclusion, the present study reports the differences in multiplicity of infection and distribution of specific alleles of msp-1, msp-2, and glurp genes in P. falciparum isolates obtained from treatment failure and successful treatment patients following artemisinin derivatives combination therapy.
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Affiliation(s)
| | - Thirasak Hoonchaiyapoom
- Bureau of Vector Borne Disease, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Kornnarin Inorn
- Bansomdejchaopraya Rajabhat University, Bangkok 10600, Thailand
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5
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Abdul-Ghani R, Al-Maktari MT, Al-Shibani LA, Allam AF. A better resolution for integrating methods for monitoring Plasmodium falciparum resistance to antimalarial drugs. Acta Trop 2014; 137:44-57. [PMID: 24801884 DOI: 10.1016/j.actatropica.2014.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 12/16/2022]
Abstract
Effective chemotherapy is the mainstay of malaria control. However, resistance of falciparum malaria to antimalarial drugs compromised the efforts to eliminate the disease and led to the resurgence of malaria epidemics. Three main approaches are used to monitor antimalarial drug efficacy and drug resistance; namely, in vivo trials, in vitro/ex vivo assays and molecular markers of drug resistance. Each approach has its implications of use as well as its advantages and drawbacks. Therefore, there is a need to use an integrated approach that would give the utmost effect to detect resistance as early as its emergence and to track it once spread. Such integration becomes increasingly needed in the era of artemisinin-based combination therapy as a forward action to deter resistance. The existence of regional and global networks for the standardization of methodology, provision of high quality reagents for the assessment of antimalarial drug resistance and dissemination of open-access data would help in approaching an integrated resistance surveillance system on a global scale.
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6
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Abstract
In the past, assessment of drug efficacy against Plasmodium falciparum malaria has been performed by microscopy, screening for parasites in blood smears. However, in areas of high endemicity, reappearing parasites might be derived from new inoculations and could be classified falsely as treatment failures. Recently, a number of studies have used polymerase chain reaction (PCR) analysis of detectable parasites after drug administration to discriminate new infections from true recrudescence. The feasibility, high sensitivity and high resolution of this technique proves that it will be practical and highly valuable in studies on both drug resistance and vaccine efficacy as well as the testing of novel antimalarial drugs. In this article, Georges Snounou and Hans-Peter Beck discuss the uncertainties in the interpretation of data inherent to the technical limitations of the PCR technique, and the constraints imposed by the biology of the parasite. They suggest that although genotyping can provide strong evidence for differentiating between true recrudescence and reinfection, it must be interpreted with caution. They also propose strategies that might help minimize these uncertainties.
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Affiliation(s)
- G Snounou
- Department of Infection and Tropical Medicine, Imperial College School of Medicine, Lister Unit, Northwick Park Hospital, Harrow, Middlesex, UK HA1 3UJ
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7
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Lozano JM, Montoya-Fajardo FJ, Hoebeke J, Cifuentes GH, Forero M, Patarroyo ME. Antibodies induced by Plasmodium falciparum merozoite surface antigen-2-designed pseudopeptides possess neutralizing properties of the in vitro malarial infection. Peptides 2007; 28:1954-65. [PMID: 17881088 DOI: 10.1016/j.peptides.2007.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/04/2007] [Accepted: 07/06/2007] [Indexed: 10/23/2022]
Abstract
Pseudopeptide chemistry is gaining ground in the field of synthetic vaccine development. We have previously demonstrated the potential scope of introducing reduced amide peptide bond isosters in a site-directed design for obtaining structurally modified probes able to induce malaria infection-neutralizing antibodies derived from the MSP-1 antigen. This work reports the functional properties of polyclonal and monoclonal antibodies induced by site-directed designed MSP-2 N-terminus pseudopeptides and their capacity for antibody isotype switching in in vitro immunization. Structural properties of the native peptide and its pseudopeptide analogs are discussed within the context of these novel pseudopeptides' induced monoclonal antibody functional and physical-chemical properties.
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Fowler EV, Chavchich M, Chen N, Peters JM, Kyle DE, Gatton ML, Cheng Q. Physical linkage to drug resistance genes results in conservation of var genes among West Pacific Plasmodium falciparum isolates. J Infect Dis 2006; 194:939-48. [PMID: 16960782 PMCID: PMC1564382 DOI: 10.1086/506619] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Accepted: 04/10/2006] [Indexed: 11/03/2022] Open
Abstract
The multicopy var gene family encoding the variant surface antigen Plasmodium falciparum erythrocyte membrane protein 1 is highly diverse, with little overlap between different P. falciparum isolates. We report 5 var genes (varS1-varS5) that are shared at relatively high frequency among 63 genetically diverse P. falciparum isolates collected from 5 islands in the West Pacific region. The varS1, varS2, and varS3 genes were localized to the internal region on chromosome 4, approximately 200 kb from pfdhfr-ts, whereas varS4 and varS5 were mapped to an internal region of chromosome 7, within 100 kb of pfcrt. The presence of varS2 and varS3 were significantly correlated with the pyrimethamine-resistant pfdhfr genotype, whereas varS4 was strongly correlated with the chloroquine-resistant pfcrt genotype. Thus, the conservation of these var genes is the result of their physical linkage with drug-resistant genes in combination with the antimalarial drug pressure in the region.
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Affiliation(s)
- Elizabeth V Fowler
- Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia
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Ferreira MU, Hartl DL. Plasmodium falciparum: worldwide sequence diversity and evolution of the malaria vaccine candidate merozoite surface protein-2 (MSP-2). Exp Parasitol 2006; 115:32-40. [PMID: 16797008 DOI: 10.1016/j.exppara.2006.05.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [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: 03/02/2006] [Revised: 04/06/2006] [Accepted: 05/11/2006] [Indexed: 10/24/2022]
Abstract
We examined patterns and putative mechanisms of sequence diversification in the merozoite surface protein-2 (MSP-2) of Plasmodium falciparum, a major dimorphic malaria vaccine candidate antigen, by analyzing 448 msp-2 alleles from all continents. We describe several nucleotide replacements, insertion and deletion events, frameshift mutations, and proliferations of repeat units that generate the extraordinary diversity found in msp-2 alleles. We discuss the role of positive selection exerted by naturally acquired type- and variant-specific immunity in maintaining the observed levels of polymorphism and suggest that this is the most likely explanation for the significant excess of nonsynonymous nucleotide replacements found in dimorphic msp-2 domains. Hybrid sequences created by meiotic recombination between alleles of different dimorphic types were observed in few (3.1%) isolates, mostly from Africa. We found no evidence for an extremely ancient origin of allelic dimorphism at the msp-2 locus, predating P. falciparum speciation, in contrast with recent findings for other surface malarial antigens.
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Affiliation(s)
- Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil.
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Chen N, Kyle DE, Pasay C, Fowler EV, Baker J, Peters JM, Cheng Q. pfcrt Allelic types with two novel amino acid mutations in chloroquine-resistant Plasmodium falciparum isolates from the Philippines. Antimicrob Agents Chemother 2004; 47:3500-5. [PMID: 14576108 PMCID: PMC253797 DOI: 10.1128/aac.47.11.3500-3505.2003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations in the pfcrt and pfmdr1 genes have been associated with chloroquine resistance in Plasmodium falciparum. Ten and five mutations, respectively, have been identified in these genes from chloroquine-resistant parasites worldwide. Mutation patterns in pfcrt revealed that chloroquine resistance evolved independently in southeast Asia, South America, and Papua New Guinea. However, the evolution of chloroquine resistance in the rest of the Pacific region is unclear. In this study, we examined sequence polymorphisms in these genes in isolates from Morong, Philippines, and compared them to known chloroquine resistance sequences. Two novel mutations, A144T and L160Y, were identified outside of the 10 known mutations in pfcrt in Morong isolates. These novel mutations were identified only in parasites with K76T and N326D but without the common A220S mutation found in most chloroquine-resistant isolates. This represents a unique chloroquine resistance allelic type (K76T/A144T/L160Y/N326D) not previously found elsewhere in the world. One Morong isolate also had an additional C72S mutation, whereas only one isolate possessed an allelic type typical of chloroquine resistance in Asia. Parasites with the novel pfcrt allelic types were resistant to chloroquine in vitro and were unresponsive to verapamil (0.9 microM) chemosensitization, similar to chloroquine-resistant parasites from South America and Papua New Guinea. These results suggest that chloroquine resistance evolved independently in the Philippines and represents a second chloroquine resistance founder event in the South Pacific.
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Affiliation(s)
- Nanhua Chen
- Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Enoggera, Qld, Australia
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Denis MB, Davis TME, Hewitt S, Incardona S, Nimol K, Fandeur T, Poravuth Y, Lim C, Socheat D. Efficacy and safety of dihydroartemisinin-piperaquine (Artekin) in Cambodian children and adults with uncomplicated falciparum malaria. Clin Infect Dis 2002; 35:1469-76. [PMID: 12471565 DOI: 10.1086/344647] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [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: 05/16/2002] [Accepted: 08/15/2002] [Indexed: 11/04/2022] Open
Abstract
The safety and efficacy of a novel combination of dihydroartemisinin (DHA) and piperaquine, Artekin (Holleykin Pharmaceuticals), were assessed in 106 patients (76 children and 30 adults) with uncomplicated falciparum malaria from 2 remote areas in Cambodia. Age-based doses were given at 0, 8, 24, and 32 h. Mean total DHA and piperaquine doses were 9.1 and 73.9 mg/kg, respectively, for children and 6.6 and 52.9 mg/kg for adults. All patients became aparasitemic within 72 h. Excluding the results for 1 child who died on day 4, there was a 96.9% 28-day cure rate (98.6% in children and 92.3% in adults). Patients who had recrudescent infection received low doses of Artekin. Side effects were reported by 22 patients (21%) but did not necessitate premature cessation of therapy. Although Artekin is a promising and inexpensive option for antimalarial therapy, further efficacy and pharmacokinetic studies are needed, especially for its use in children.
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Affiliation(s)
- Mey Bouth Denis
- European Commission, Cambodia Malaria Control Programme, and National Malaria Centre, Phnom Penh, Cambodia
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Weisman S, Wang L, Billman-Jacobe H, Nhan DH, Richie TL, Coppel RL. Antibody responses to infections with strains of Plasmodium falciparum expressing diverse forms of merozoite surface protein 2. Infect Immun 2001; 69:959-67. [PMID: 11159991 PMCID: PMC97975 DOI: 10.1128/iai.69.2.959-967.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [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] Open
Abstract
Individuals living in areas where Plasmodium falciparum is endemic experience numerous episodes of infection. These episodes may or may not be symptomatic, with the outcome depending on a combination of parasite and host factors, several of which are poorly understood. One factor is believed to be the particular alleles of several parasite proteins to which the host is capable of mounting protective immune responses. We report a study examining antibody responses to MSP2 in 15 semi-immune teenagers and adults living in the Khanh-Hoa area of southern-central Vietnam, where P. falciparum is highly endemic; subjects were serially infected with multiple strains of P. falciparum. The MSP2 alleles infecting these subjects were determined by nucleotide sequencing. A total of 62 MSP2 genes belonging to both dimorphic families were identified, of which 33 contained distinct alleles, with 61% of the alleles being detected once. Clear changes in the repertoire occurred between infections. Most infections contained a mixture of parasites expressing MSP2 alleles from both dimorphic families. Two examples of reinfection with a strain expressing a previously encountered allele were detected. Significant changes in antibody levels to various regions of MSP2 were detected over the course of the experiment. There was no clear relation between the infecting form of MSP2 and the ensuing antibody response. This study highlights the complexity of host-parasite relationship for this important human pathogen.
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Affiliation(s)
- S Weisman
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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Cheng Q, Cloonan N, Fischer K, Thompson J, Waine G, Lanzer M, Saul A. stevor and rif are Plasmodium falciparum multicopy gene families which potentially encode variant antigens. Mol Biochem Parasitol 1998; 97:161-76. [PMID: 9879895 DOI: 10.1016/s0166-6851(98)00144-3] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.7] [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: 11/25/2022]
Abstract
Several multicopy gene families have been described in Plasmodium falciparum, including the var genes that code for the variant surface antigen PfEMP1, the stevor family of subtelomeric open reading frames and the rif interspersed repetitive elements. This report documents the chromosomal location of stevor genes, their transcription and characteristics of the deduced protein. On 14 chromosomes, 34 stevor copies were identified from the Dd2 parasite line. Most are in subtelomeric regions within 50 kb of the telomere. stevor genes are located close to var genes and rij. All stevor genes sequenced had two exons: a short exon 1 encoding a start codon and a transmembrane domain; exon 2 encoding for the remainder of the approximately 30 kDa protein and including two more transmembrane segments. A similar structure was found for copies of rif and its predicted protein. In both STEVOR and RIF proteins, a highly polymorphic region is predicted to be a loop on the outer side of the membrane. We propose that stevor and rif are members of a larger superfamily. The number of copies of stevor and rif, their location close to the var genes, their extreme polymorphism and the predicted structure of the proteins suggest that stevor and rif code for variant surface antigens.
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Affiliation(s)
- Q Cheng
- The Queensland Institute of Medical Research, Royal Brisbane Hospital, Australia
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Abstract
We have studied the immunogenicity of a recombinant heat-shock protein-related stress protein of 70,000 MW (Pfhsp) of the human malaria parasite Plasmodium falciparum in H-2 congenic and non-congenic strains of inbred and outbred mice. Most mice of different genetic backgrounds produced antibodies to Pfhsp, indicating a lack of any apparent genetic restriction of immune response. A peptide corresponding to the GGMP repeat sequence in the C-terminal region of Pfhsp was recognized by more than 75% of sera from immunized mice. The GGMP repeat epitope-specific antibodies were largely of the IgM isotype, especially in all seven inbred strains of mice tested. The lack of significant boosting of the immune response, a predominantly IgM isotype of antibodies and generation of antibody responses in athymic nude mice suggest a thymus-independent response against the GGMP repeat epitope in the Pfhsp molecule.
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Affiliation(s)
- N Kumar
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, School of Public Health, Baltimore, MD 21205, USA
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15
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Abstract
Extensive polymorphism of key parasite antigens is likely to hamper the effectiveness of subunit vaccines against Plasmodium falciparum infection. However, little is known about the extent of the antigenic repertoire of naturally circulating strains in different areas where malaria is endemic. To address this question, we conducted a study in which blood samples were collected from parasitemic individuals living within a small hamlet in Western Irian Jaya and subjected to PCR amplification using primers that would allow amplification of the gene encoding merozoite surface protein-2 (MSP2). We determined the nucleotide sequence of the amplified product and compared the deduced amino acid sequences to sequences obtained from samples collected in the same hamlet 29 months previously. MSP2 genes belonging to both major allelic families were observed at both time points. In the case of the FC27 MSP2 family, we observed that the majority of individuals were infected by parasites expressing the same form of MSP2. Infections with parasites expressing 3D7 MSP2 family alleles were more heterogeneous. No MSP2 alleles observed at the earlier time point were detectable at the later time point, either for the population as a whole or for individuals who were assayed at both time points. We examined a subset of the infected patients by using blood samples taken between the two major surveys. In no patients could we detect reinfection by a parasite expressing a previously encountered form of MSP2. Our results are consistent with the possibility that infection induces a form of strain-specific immune response against the MSP2 antigen that biases against reinfection by parasites bearing identical forms of MSP2.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Antigens, Protozoan
- Chromosome Mapping
- DNA Primers/genetics
- DNA, Protozoan/analysis
- DNA, Protozoan/genetics
- Genome, Protozoan
- Humans
- Indonesia/epidemiology
- Malaria, Falciparum/blood
- Malaria, Falciparum/epidemiology
- Malaria, Falciparum/genetics
- Molecular Epidemiology
- Molecular Sequence Data
- Parasitemia/blood
- Parasitemia/epidemiology
- Parasitemia/genetics
- Plasmodium falciparum/genetics
- Polymerase Chain Reaction
- Polymorphism, Genetic
- Protozoan Proteins/genetics
- Repetitive Sequences, Nucleic Acid
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- D Eisen
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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16
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Abstract
Direct microscopy is widely used for the diagnosis of parasitic infections although it often requires an experienced microscopist for accurate diagnosis, is labour intensive and not very sensitive. In order to overcome some of these shortcomings, molecular or nucleic acid-based diagnostic methods for parasitic infections have been developed over the past 12 years. The parasites which have been studied with these techniques include the human Plasmodia, Leishmania, the trypanosomes, Toxoplasma gondii, Entamoeba histolytica, Giardia, Trichomonas vaginalis, Cryptosporidium parvum, Taenia, Echinococcus, Brugia malayi, Wuchereria bancrofti, Loa loa and Onchocerca volvulus. Early methods, which involved hybridisation of specific probes (radiolabelled and non-radiolabelled) to target deoxyribonucleic acid (DNA), have been replaced by more sensitive polymerase chain reaction (PCR)-based assays. Other methods, such as PCR-hybridisation assays, PCR-restriction fragment length polymorphism (PCR-RFLP) assays and random amplified polymorphic DNA (RAPD) analysis have also proved valuable for epidemiological studies of parasites. The general principles and development of DNA-based methods for diagnosis and epidemiological studies will be described, with particular reference to malaria. These methods will probably not replace current methods for routine diagnosis of parasitic infections in developing countries where parasitic diseases are endemic, due to high costs. However, they will be extremely useful for genotyping parasite strains and vectors, and for accurate parasite detection in both humans and vectors during epidemiological studies.
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Affiliation(s)
- B Singh
- Department of Medical Microbiology and Parasitology, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia.
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Ntoumi F, Rogier C, Dieye A, Trape JF, Millet P, Mercereau-Puijalon O. Imbalanced Distribution of Plasmodium falciparum MSP-1 Genotypes Related to Sickle-Cell Trait. Mol Med 1997. [DOI: 10.1007/bf03401815] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Ntoumi F, Mercereau-Puijalon O, Ossari S, Luty A, Reltien J, Georges A, Millet P. Plasmodium falciparum: sickle-cell trait is associated with higher prevalence of multiple infections in Gabonese children with asymptomatic infections. Exp Parasitol 1997; 87:39-46. [PMID: 9287956 DOI: 10.1006/expr.1997.4173] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [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: 02/05/2023]
Abstract
Through PCR amplifications of the gene encoding the merozoite surface antigen 2, utilizing allele-specific 3D7 and FC27 probes, we have examined the prevalence of Plasmodium falciparum in children aged from 7 to 14 years living in a village located in the equatorial forest region of Central Africa (Gabon). Using this technique, 61% (100/163) of the blood samples were shown to be infected with P. falciparum with 24 alleles distinguished by size polymorphism and sequence type. The two main families (3D7 and FC27) and hybrid alleles were detected regardless of sex and hemoglobin phenotype. No age-related changes in prevalence of P. falciparum strains were observed; however, the prevalence of infection (42%) was significantly lower in individuals with the sickle-cell trait compared with their normal-hemoglobin counterparts (68%). Mixtures of genetically distinct parasite clones were present in 82% of children carrying the sickle-cell trait but in only 58% of normal-hemoglobin carriers. The significance of these observations regarding the design and interpretation of epidemiological investigations is discussed in the context of malaria transmission in the region studied.
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Affiliation(s)
- F Ntoumi
- International Centre for Medical Research, Franceville, Gabon, France
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Abstract
Three different polymerase chain reaction assays for the typing of isolates of Babesia bovis have been developed and compared with a hybridisation based method. Primers were designed within conserved regions flanking the variable length tandem repeats of the Bv80 and BvVA1 genes. For the long array of repeats in BvVA1, up to 7.5 kb, a modified long template PCR method was developed. The assays were compared using ten independent isolates of Babesia bovis. Using the BvVA1 and Bv80 PCR assays, 13 and 10 genotypes could be discriminated, respectively, with some isolates containing several genotypes. Combining the two PCR assays, 17 genotypes were identified within the ten Babesia bovis isolates. Whilst simpler and requiring less DNA, the BvVA1 PCR analysis exhibited significant bias towards some genotypes of the BvVA1 repeats. Further discrimination of BvVA1 PCR products was achieved using AccI digests producing population specific ladders. Genomic DNA fingerprints were also generated by PCR of DNA using an arbitrary primer (randomly amplified polymorphic DNA, RAPD) revealing polymorphic genotypes that were isolate specific. No amplification of host DNA resulted from any of the three PCR procedures. Babesia bigemina DNA was not amplified by the Bv80 or BvVA1 primers. Applications demonstrating changes in composition of populations of Babesia bovis parasites during attenuation and prolonged culture maintenance are described.
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Affiliation(s)
- A E Lew
- Animal Research Institute, Queensland Department of Primary Industries, Moorooka, Australia.
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20
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Felger I, Marshal VM, Reeder JC, Hunt JA, Mgone CS, Beck HP. Sequence diversity and molecular evolution of the merozoite surface antigen 2 of Plasmodium falciparum. J Mol Evol 1997; 45:154-60. [PMID: 9236275 DOI: 10.1007/pl00006215] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Eleven new alleles of the Plasmodium falciparum merozoite surface antigen 2 (MSA2) from Papua New Guinea were analyzed by direct sequencing of polymerase chain reaction (PCR) products. We have used the sequence information to trace the molecular evolution of MSA2. The repeats of ten alleles belonging to the 3D7 allelic family differed considerably in size, nucleotide sequence, and repeat copy number. In the repeat region of these new alleles, codon usage was extremely biased with an exclusive use of NNT codons. Another new allele sequenced belonged to the FC27 family and confirmed the family-specific conserved structure of 96 and 36 bp repeats. In order to assess sequence microheterogeneity within samples defined as the same genotype by restriction fragment length polymorphism (RFLP), we have analyzed single-strand conformation polymorphism (SSCP) of different samples of the most frequent allele (D10 of the FC27 family) in the study population. No sequence heterogeneity could be detected within the repeat region. Based on analysis of the repeat regions in both allelic families, we discuss the hypothesis of a different evolutionary strategy being represented by each of the allelic families. Kew words: Merozoite surface antigen 2 - Nucleotide sequence comparisons - Molecular evolution
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Affiliation(s)
- I Felger
- Institut für Zellbiologie, Universität Witten-Herdecke, Stockumer Str. 10, 58448 Witten, Germany
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21
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Huber W, Felger I, Matile H, Lipps HJ, Steiger S, Beck HP. Limited sequence polymorphism in the Plasmodium falciparum merozoite surface protein 3. Mol Biochem Parasitol 1997; 87:231-4. [PMID: 9247935 DOI: 10.1016/s0166-6851(97)00067-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- W Huber
- Swiss Tropical Institute, Basel, Switzerland
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22
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Dobaño C, Khan A, Robinson JV, Taylor RR, Mcbride JS. Identical alleles of Plasmodium falciparum merozoite surface protein 2 found in distant geographic areas and times. Parasitol Int 1997; 46:137-42. [DOI: 10.1016/s1383-5769(97)00020-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Abstract
In recent years there has been a considerable debate on the population genetic structure of malaria parasites. Work on this subject has been revolutionized by the advent of the polymerase chain reaction (PCR) technique, which has made it feasible to study the genetic diversity of parasites in small samples of infected blood, allowing extensive surveys of natural parasite populations to be made. In addition, the technique can be applied to the mosquito stages of the malaria parasite, allowing direct assessments to be trade of the frequency of crossing between parasite clones in Nature. Studies on Plasmodium falcjparum in a wide range of malaria-endemic regions are now revealing the relationship between parasite population structure and malaria epidemiology. In this article, Hamza Babiker and David Walliker review recent work in this field, and discuss how such knowledge might be used to advise on the future deployment of control measures such as antimalarial drugs and possible malaria vaccines.
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Affiliation(s)
- H A Babiker
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, West Mains Road, Edinburgh, UK.
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24
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Rzepczyk CM, Hale K, Woodroffe N, Bobogare A, Csurhes P, Ishii A, Ferrante A. Humoral immune responses of Solomon Islanders to the merozoite surface antigen 2 of Plasmodium falciparum show pronounced skewing towards antibodies of the immunoglobulin G3 subclass. Infect Immun 1997; 65:1098-100. [PMID: 9038322 PMCID: PMC175094 DOI: 10.1128/iai.65.3.1098-1100.1997] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The immunoglobulin G (IgG) subclass distribution of antibodies to merozoite surface antigen 2 of Plasmodium falciparum in Solomon Islanders showed marked skewing towards the IgG3 subclass. This was not observed with crude P. falciparum schizont antigen. IgG3 responses may be short-lived and require repeated restimulation for their maintenance. This may be provided by persistent infection (premunition) or new infections.
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Affiliation(s)
- C M Rzepczyk
- Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, Herston, Brisbane.
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25
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Robert F, Ntoumi F, Angel G, Candito D, Rogier C, Fandeur T, Sarthou JL, Mercereau-Puijalon O. Extensive genetic diversity of Plasmodium falciparum isolates collected from patients with severe malaria in Dakar, Senegal. Trans R Soc Trop Med Hyg 1996; 90:704-11. [PMID: 9015525 DOI: 10.1016/s0035-9203(96)90446-0] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.1] [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: 02/03/2023] Open
Abstract
While some genetic host factors are known to protect against severe Plasmodium falciparum malaria, little is known about parasite virulence factors. We have compared the genetic characteristics of P. falciparum isolates collected from 56 severe malaria patients and from 30 mild malaria patients recruited in Hôpital Principal, Dakar, Senegal. All isolates were typed using polymerase chain reaction amplification of polymorphic genetic loci (MSP-1, MSP-2, HRP1, GLURP, CSP, RESA, and the multigene family Pf60). The complexity of infections was lower in severe than in mild malaria and the parasite genetic diversity in both groups was very large. No specific genetic make-up was associated with severity; there were, however, marked differences in allele frequencies in both groups, with a prevalence up to 60% of MSP-2 alleles specifically observed in the severe malaria isolates. In addition, the presence of MSP-1/RO33 alleles was significantly associated with a higher plasma level of tumour necrosis factor alpha receptor 1 (P < 0.05), a reported indicator of severity in human malaria. These results point to potential differences in the genetic characteristics of parasites inducing severe versus mild pathology.
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Affiliation(s)
- F Robert
- Unité d'Immunologie Moléculaire des Parasites, Institut Pasteur, Paris, France
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26
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Kain KC, Craig AA, Ohrt C. Single-strand conformational polymorphism analysis differentiates Plasmodium falciparum treatment failures from re-infections. Mol Biochem Parasitol 1996; 79:167-75. [PMID: 8855553 DOI: 10.1016/0166-6851(96)02656-4] [Citation(s) in RCA: 16] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Paired primary and recrudescent Plasmodium falciparum isolates were collected from treatment failures identified during the course of antimalarial drug studies on the Thai-Cambodian border. Ten paired samples were subjected to PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformational polymorphism (PCR-SSCP) analysis of the MSP-2 gene. PCR-SSCP analysis of paired samples demonstrated that each recrudescent isolate was identical to, or a subpopulation of, its matched primary isolate and was distinct from all unrelated isolates. This method represents a field applicable method to distinguish re-infections from treatment failures when antimalarial drug studies are performed in malaria-endemic areas.
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Affiliation(s)
- K C Kain
- Department of Medicine, University of Toronto, Canada.
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27
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Taylor RR, Smith DB, Robinson VJ, McBride JS, Riley EM. Human antibody response to Plasmodium falciparum merozoite surface protein 2 is serogroup specific and predominantly of the immunoglobulin G3 subclass. Infect Immun 1995; 63:4382-8. [PMID: 7591074 PMCID: PMC173623 DOI: 10.1128/iai.63.11.4382-4388.1995] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
MSP2 is a merozoite surface protein of Plasmodium falciparum and, as such, is a potential component of a malaria vaccine. In this study, we have used a panel of recombinant MSP2 antigens in enzyme-linked immunosorbent assays to investigate the recognition of MSP2 by antibodies from malaria-immune human serum. These recombinant antigens include full-length proteins of serogroups A and B and fragments representing the conserved, group-specific, or repeat regions of each serogroup. Ninety-five percent of the serum samples tested contained MSP2-specific antibodies: 81% of serum samples tested responded to serogroup A, and 86% responded to serogroup B. The antibody response is directed almost exclusively towards dimorphic and polymorphic regions of MSP2; the conserved regions are rarely recognized, and antibodies to serogroups A and B do not cross-react. Interestingly, the antibody response is predominately of the cytophilic and complement-fixing subclass immunoglobulin G3.
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Affiliation(s)
- R R Taylor
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, Scotland
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28
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Bhattacharya P, Malhotra P, Sharma P, Okenu DM, Chauhan VS. Merozoite surface antigen 2 (MSA-2) gene of Plasmodium falciparum strains from India. Mol Biochem Parasitol 1995; 74:125-7. [PMID: 8719253 DOI: 10.1016/0166-6851(96)83010-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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29
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Abstract
We report on an analysis of the constraints of PCR typing of field Plasmodium falciparum isolates by using a few highly polymorphic markers, MSA-1, MSA-2, TRAP, and CS. We show that the reactions are specific for the P. falciparum species. The detection threshold (minimum number of parasites required to detect a visible band by ethidium bromide) differed from one marker to the other and, within one locus, from one primer combination to the other. Importantly, the various MSA-1 and MSA-2 reference alleles were amplified with the same efficiency. Amplification from reconstituted allele mixtures indicated that at certain allele ratios, the most abundant allele interfered with the amplification of the less abundant one. An analysis of nine isolates collected from patients with acute malaria in Dielmo, Senegal, during a transmission season when the inoculation rate was one infective bite every second night is presented and discussed. All samples contained more than one parasite type. A significant polymorphism was observed for the four markers. Novel TaqI restriction fragment length polymorphisms were found for the TRAP gene, and TRAP gene typing alone allowed a distinction between the various isolates. MSA-1 and MSA-2 gave multiple band patterns specific for each sample.
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Affiliation(s)
- H Contamin
- Unité de Parasitologie Expérimentale, Institut Pasteur, Paris, France
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30
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Kimura M, Kaneko O, Inoue A, Ishii A, Tanabe K. Amplification by polymerase chain reaction of Plasmodium falciparum DNA from Giemsa-stained thin blood smears. Mol Biochem Parasitol 1995; 70:193-7. [PMID: 7637702 DOI: 10.1016/0166-6851(95)00006-m] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- M Kimura
- Laboratory of Biophysics, Osaka City University Medical School, Japan
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31
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Reeder JC, Marshall VM. A simple method for typing Plasmodium falciparum merozoite surface antigens 1 and 2 (MSA-1 and MSA-2) using a dimorphic-form specific polymerase chain reaction. Mol Biochem Parasitol 1994; 68:329-32. [PMID: 7739680 DOI: 10.1016/0166-6851(94)90179-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- J C Reeder
- Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Victoria, Australia
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