Merozoite surface protein-1 genetic diversity in Plasmodium malariae and Plasmodium brasilianum from Brazil

Abstract

BackgroundThe merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America.MethodsSpecific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites.ResultsExcept for fragment 4, sequences from all other fragments consisted of unpublished sequences. The most polymorphic gene region was fragment 2, and in samples where this region lacks polymorphism, all other regions are also identical. The low variability of the P. malariae msp1 sequences of these isolates and the identification of the same haplotype in those collected many years apart at different locations is compatible with a low transmission rate. We also found greater diversity among P. brasilianum isolates compared with P. malariae ones. Lastly, the sequences were segregated according to their geographic origins and hosts, showing a strong genetic and geographic structure.ConclusionsOur data show that there is a low level of sequence diversity and a possible absence of allelic dimorphism of MSP1 in these parasites as opposed to other Plasmodium species. P. brasilianum strains apparently show greater divergence in comparison to P. malariae, thus P. malariae could derive from P. brasilianum, as it has been proposed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1238-8) contains supplementary material, which is available to authorized users.

Plasmodium malariaePrevalence andcspGene Diversity, Kenya, 2014 and 2015

“…This variation could be attributed to positive selection, frequent recombination, and gene flow among the parasites, as follows. First, compared with msp 1, dhfr , and dhps of P. malariae ( 20 – 22 ), the csp gene revealed a remarkably higher level of sequence diversity. It is possible that selection of csp genetic variants may confer immunogenic advantages to the pathogen during host invasion ( 28 , 47 ).…”

“…Knowledge of genetic variation among isolates from these geographic areas is still lacking. One study indicated a remarkably low level of sequence diversity at the msp 1 locus in P. malariae from Brazil ( 20 ). Similarly, the lack of variation at the dhfr and dhps loci has been shown for P. malariae from Asia and the western Pacific region ( 21 , 22 ).…”

Plasmodium malariae and Plasmodium ovale infections in the China–Myanmar border area

“…P. falciparum and P. vivax MSP - 1 genes display extensive genetic diversity, which is often used as a molecular marker for population studies. To date, limited studies on PmMSP - 1 among Brazilian isolates and PocMSP - 1 on Thai isolates detected low-level sequence diversity with most of variations located at interspecies variable domains of this gene [46, 48]. Phylogenetic analysis of PmMSP - 1 using the maximum likelihood method placed the China–Myanmar border isolates separated from the Brazilian isolates, indicating divergent parasite populations.…”

“…These include the cytochrome b ( cytb ), cytochrome oxidase subunit 1 ( cox1 ) and glyceraldehyde - 3 - phosphate ( g3p ) genes of P. ovale spp., dihydropoteroate synthase ( dhps ) of P. malariae [43], dihydrofolate reductase ( dhfr ) and MSP - 1 genes in both species [44–46]. Amplified fragments of DNA were purified, and sequenced directly or cloned into pMD18-T vector (Takara) for sequencing.…”

ElusivePlasmodiumSpecies Complete the Human Malaria Genome Set

“…It has been suggested that a new world primate infective 160 species termed P. brasilianum is identical to P. malariae 21 . To investigate this further using the new genome assemblies, we aligned the P. brasilianum merozoite surface protein 1 (MSP1) 22 and ribosomal rRNA 21 genes to both the P. malariae and P. malariae-like orthologous genes, showing that P. brasilianum is identical to P. malariae, but that P. malariae-like is indeed very different (Supplementary Figure 165 2b).…”