Genetic diversity of Plasmodium vivax metacaspase 1 and Plasmodium vivax multi-drug resistance 1 genes of field isolates from Mauritania, Sudan and Oman

Abstract

Background Plasmodium vivax is the second most important human malaria parasite, widely spread across the world. This parasite is associated with important issues in the process toward malaria elimination, including potential for relapse and increased resistance to chloroquine. Plasmodium vivax multi-drug resistant (pvmdr1) is suspected to be a marker of resistance although definitive evidence is lacking. Progress has been made in knowledge of biological factors affecting parasite growth, including mechanisms of regulated cell death and the suspected role of metacaspase. Plasmodium vivax metacaspase1 (PvMCA1-cd) has been described with a catalytic domain composed of histidine (H372) and cysteine (C428) residues. The aim of this study was to test for a link between the conserved histidine and cysteine residues in PvMCA1-cd, and the polymorphism of the P. vivax multi-drug resistant gene (pvmdr1).ResultsThirty P. vivax isolates were collected from Mauritania, Sudan, and Oman. Among the 28 P. vivax isolates successfully sequenced, only 4 samples showed the conserved His (372)–Cys (428) residues in PvMCA1-cd. Single nucleotide polymorphisms observed were H372T (46.4%), H372D (39.3%), and C428R (85.7%). A new polymorphic catalytic domain was observed at His (282)–Cys (305) residues. Sequences alignment analysis of pvmdr1 showed SNP in the three codons 958, 976 and 1076. A single SNP was identified at the codon M958Y (60%), 2 SNPs were found at the position 976: Y976F (13%) and Y976V (57%), and 3 SNPs were identified at the position 1076: F1076L (40%), F1076T (53%) and F1076I (3%). Only one isolate was wildtype in all three codons (MYF), 27% were single MYL mutants, and 10% were double MFL mutants. Three new haplotypes were also identified: the triple mutant YVT was most prevalent (53.3%) distributed in the three countries, while triple YFL and YVI mutants (3%), were only found in samples from Sudan and Mauritania.ConclusionsTriple or quadruple mutants for metacaspase genes and double or triple mutants for Pvmdr1 were observed in 24/28 and 19/28 samples. There was no difference in the frequency of mutations between PvMCA1-cd and Pvmdr1 (P > 0.2). Histidine and cysteine residues in PvMCA1-cd are highly polymorphic and linkage disequilibrium with SNPs of Pvmdr1 gene may be expected from these three areas with different patterns of P. vivax transmission.

Genotyping cognate Plasmodium falciparum in humans and mosquitoes to estimate onward transmission of asymptomatic infections

“…Mosquito feeding experiments employing either direct skin or membrane feeding fail to represent numerous participant-, mosquito-, and parasite-related factors that are critical to transmission. These critical factors include variance among mosquito vectors in biting preferences 28 , behaviors 26 , and success 29 ; among parasites in replication rates 27 and gametocyte production 30 ; and among participants in exposure to vectors 31 and care-seeking behavior 32 . Similarly, this complexity also confounds the use of gametocyte prevalence or density as a proxy for transmission 33 , which may more precisely define which infections can rather than do transmit.…”

An outbreak of locally acquired Plasmodium vivax malaria among migrant workers in Oman

“…Dry blood films from 45 different patients were obtained by scrapping off the surface of the smear with a scalpel and re-suspending in 100 μL of phosphate-buffered saline (PBS) [ 33 ]. Genomic DNA was extracted using a QIAamp DNA mini kit (Qiagen) according to the manufacturer’s instructions.…”

Plasmodium vivax metacaspase 1 (PvMCA1) catalytic domain is conserved in field isolates from Brazilian Amazon

“…To investigate the genetic diversity of Pv MCA1, eighty-three wild isolates of P. vivax from Juruá Valley in the Brazilian Amazon were submitted to DNA sequencing for gene segment coding the consensus His372-Cys428 catalytic dyad (13). In contrast to work by Sow et al, 15 in which the majority of isolates (24/28, 85.7%) presented amino acid substitution in both catalytic dyad and an upstream cysteine residue (Cys305) also inserted in the peptidase C14 domain, all the isolates herein studied showed complete nucleotide sequence identity each other as well as compared to P. vivax Sal-1 reference, with conservation of all the amino acid residues successfully sequenced (A288 to K446) ( Fig. 1 ), supporting that the proteolytic activity of Pv MCA1 may be critical to the parasite.…”

“…They present structural similarity to metazoan caspases, both having a conserved His-Cys catalytic dyad in the large (p20) domain, but different substrate specificity. 13 In Plasmodium genomes, three metacaspases (MCA1-3) occur 14 and a study performed with field isolates from Mauritania, Sudan and Oman showed that P. vivax metacaspase 1 ( Pv MCA1) can present single nucleotide polymorphisms in the putative His-Cys catalytic residues, 15 which in some extent can be a factor limiting the eligibility of Pv MCA1 as a novel drug target for vivax malaria. In the present study, therefore, we investigated the genetic diversity of the Pv MCA1 catalytic domain in a P. vivax population from the main malaria hotspot in Brazil - a country where this plasmodial species is highly prevalent (~90%).…”

“…Gene segment coding for the catalytic domain of Pv MCA1 was amplified by standard PCR method using a pair of specific primers (forward, 5′-CATGGAAACAAAAAAAAGG-3′; reverse, 5′-CGAAAACTCCATATCTTTGC-3′), as previously described. 15 PCR was performed in a Veriti 96-well Thermal Cycler (Applied Biosystems) with a total volume of 25 μL reaction mixture containing 3 μL genomic DNA, 10 pmol/μL each primer, 2.5 unit AmpliTaq TM Gold DNA polymerase, 3 mM MgCl 2 and 2 μL of 10X PCR buffer. The following conditions were used: 35 cycles at 95ºC for 30 s, 56ºC for 30 s and 72ºC for 2 min.…”