Endoplasmic Reticulum ; genetics ; metabolism ; Plasmodium berghei ; genetics ; metabolism ; Plasmodium falciparum ; genetics ; metabolism ; Protozoan Proteins ; genetics ; metabolism

The completion of many malaria parasite genomes provides great opportunities for genomewide characterization of gene expression and high-throughput genotyping. Substantial progress in malaria genomics and genotyping has been made recently, particularly the development of various microarray platforms for large-scale characterization of the Plasmodium falciparum genome. Microarray has been used for gene expression analysis, detection of single nucleotide polymorphism (SNP) and copy number variation (CNV), characterization of chromatin modifications, and other applications. Here we discuss some recent advances in genetic mapping and genomic studies of malaria parasites, focusing on the use of high-throughput arrays for the detection of SNP and CNV in the P. falciparum genome. Strategies for genetic mapping of malaria traits are also discussed.
Animals ; *Chromosome Mapping ; DNA, Protozoan/*genetics ; Gene Dosage ; *Microarray Analysis ; Plasmodium falciparum/*genetics ; Polymorphism, Genetic

Using the complete genome of Plasmodium falciparum 3D7 which has 14 chromosomes as an example, we have examined the distribution functions for the amount of C or G and A or T consecutively and non-overlapping blocks of m bases in this system. The function P(S) about the number of the consecutive C-G or A-T content cluster conforms to the relation P(S) proportional, variante(-alphas); values of the scaling exponent alpha(CG) are much larger than alpha(AT); and alpha(AT) of 14 chromosomes are hardly changed, whereas alpha(CG) of 14 chromosomes have a number of fluctuations. We found maximum value of A-T cluster size is much larger than C-G, which implies the existence of large A-T cluster. Our study of the width function xi(m) of cluster C-G content showed that follows good power law xi(m) proportional, variantm(-gamma). The average gamma for 14 chromosomes is 0.931. These investigations provide some insight into the nucleotide clusters of DNA sequences, and help us understand other properties of DNA sequences.
Animals ; Base Composition ; Base Sequence ; Chromosomes ; genetics ; DNA, Protozoan ; genetics ; Genome, Protozoan ; Genomics ; Nucleotides ; genetics ; Plasmodium falciparum ; genetics

Merozoite surface proteins (MSPs) of malaria parasites play critical roles during the erythrocyte invasion and so are potential candidates for malaria vaccine development. However, because MSPs are often under strong immune selection, they can exhibit extensive genetic diversity. The gene encoding the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum displays 2 allelic types, K1 and 3D7. In Thailand, the allelic frequency of the P. falciparum msp-3 gene was evaluated in a single P. falciparum population in Tak at the Thailand and Myanmar border. However, no study has yet looked at the extent of genetic diversity of the msp-3 gene in P. falciparum populations in other localities. Here, we genotyped the msp-3 alleles of 63 P. falciparum samples collected from 5 geographical populations along the borders of Thailand with 3 neighboring countries (Myanmar, Laos, and Cambodia). Our study indicated that the K1 and 3D7 alleles coexisted, but at different proportions in different Thai P. falciparum populations. K1 was more prevalent in populations at the Thailand-Myanmar and Thailand-Cambodia borders, whilst 3D7 was more prevalent at the Thailand-Laos border. Global analysis of the msp-3 allele frequencies revealed that proportions of K1 and 3D7 alleles of msp-3 also varied in different continents, suggesting the divergence of malaria parasite populations. In conclusion, the variation in the msp-3 allelic patterns of P. falciparum in Thailand provides fundamental knowledge for inferring the P. falciparum population structure and for the best design of msp-3 based malaria vaccines.
Antigens, Protozoan/*genetics ; *Gene Frequency ; *Genetic Variation ; Genotype ; Humans ; Malaria, Falciparum/epidemiology/*parasitology ; Plasmodium falciparum/classification/*genetics/isolation & purification ; Polymorphism, Genetic ; Protozoan Proteins/*genetics ; Thailand/epidemiology

Mitochondrial genome sequence of malaria parasites has served as a potential marker for inferring evolutionary history of the Plasmodium genus. In Plasmodium falciparum, the mitochondrial genome sequences from around the globe have provided important evolutionary understanding, but no Indian sequence has yet been utilized. We have sequenced the whole mitochondrial genome of a single P. falciparum field isolate from India using novel primers and compared with the 3D7 reference sequence and 1 previously reported Indian sequence. While the 2 Indian sequences were highly divergent from each other, the presently sequenced isolate was highly similar to the reference 3D7 strain.
DNA, Mitochondrial/*chemistry/*genetics ; Genetic Variation ; *Genome, Mitochondrial ; Humans ; India ; Malaria, Falciparum/parasitology ; Molecular Sequence Data ; Plasmodium falciparum/*genetics/isolation & purification ; Sequence Analysis, DNA ; Sequence Homology, Nucleic Acid

Hemoglobinopathy and malaria are commonly found worldwide particularly in malaria endemic areas. Thalassemia, the alteration of globin chain synthesis, has been reported to confer resistance against malaria. The prevalence of thalassemia was investigated in 101 malaria patients with Plasmodium falciparum and Plasmodium vivax along the Thai-Myanmar border to examine protective effect of thalassemia against severe malaria. Hemoglobin typing was performed using low pressure liquid chromatography (LPLC) and alpha-thalassemia was confirmed by multiplex PCR. Five types of thalassemia were observed in malaria patients. The 2 major types of thalassemia were Hb E (18.8%) and alpha-thalassemia-2 (11.9%). There was no association between thalassemia hemoglobinopathy and malaria parasitemia, an indicator of malaria disease severity. Thalassemia had no significant association with P. vivax infection, but the parasitemia in patients with coexistence of P. vivax and thalassemia was about 2-3 times lower than those with coexistence of P. falciparum and thalassemia and malaria without thalassemia. Furthermore, the parasitemia of P. vivax in patients with coexistence of Hb E showed lower value than coexistence with other types of thalassemia and malaria without coexistence. Parasitemia, hemoglobin, and hematocrit values in patients with coexistence of thalassemia other than Hb E were significantly lower than those without coexistence of thalassemia. Furthermore, parasitemia with coexistence of Hb E were 2 times lower than those with coexistence of thalassemia other than Hb E. In conclusion, the results may, at least in part, support the protective effect of thalassemia on the development of hyperparasitemia and severe anemia in malaria patients.
Female ; Hemoglobins/genetics/metabolism ; Humans ; Malaria, Falciparum/blood/complications/*genetics/parasitology ; Malaria, Vivax/blood/complications/*genetics/parasitology ; Male ; Middle Aged ; Plasmodium falciparum/physiology ; Plasmodium vivax/physiology ; Thailand/epidemiology ; Thalassemia/blood/complications/epidemiology/*genetics

Plasmodium falciparum malaria is a major public health problem in Thailand due to the emergence of multidrug resistance. The understanding of genetic diversity of malaria parasites is essential for developing effective drugs and vaccines. The genetic diversity of the merozoite surface protein-1 (PfMSP-1) and merozoite surface protein-2 (PfMSP-2) genes was investigated in a total of 145 P. falciparum isolates collected from Mae Sot District, Tak Province, Thailand during 3 different periods (1997-1999, 2005-2007, and 2009-2010). Analysis of genetic polymorphisms was performed to track the evolution of genetic change of P. falciparum using PCR. Both individual genes and their combination patterns showed marked genetic diversity during the 3 study periods. The results strongly support that P. falciparum isolates in Thailand are markedly diverse and patterns changed with time. These 2 polymorphic genes could be used as molecular markers to detect multiple clone infections and differentiate recrudescence from reinfection in P. falciparum isolates in Thailand.
Antigens, Protozoan/*genetics ; DNA, Protozoan/genetics ; Evolution, Molecular ; Humans ; Malaria, Falciparum/parasitology ; Merozoite Surface Protein 1/*genetics ; Plasmodium falciparum/*classification/*genetics/isolation & purification ; Polymerase Chain Reaction ; *Polymorphism, Genetic ; Protozoan Proteins/*genetics ; Thailand

After invasion of red blood cells, malaria matures within the cell by degrading hemoglobin avidly. For enormous protein breakdown in trophozoite stage, many efficient and ordered proteolysis networks have been postulated and exploited. In this study, a potential interaction of a 60-kDa Plasmodium falciparum (Pf)-heat shock protein (Hsp60) and Pf-calpain, a cysteine protease, was explored. Pf-infected RBC was isolated and the endogenous Pf-Hsp60 and Pf-calpain were determined by western blot analysis and similar antigenicity of GroEL and Pf-Hsp60 was determined with anti-Pf-Hsp60. Potential interaction of Pf-calpain and Pf-Hsp60 was determined by immunoprecipitation and immunofluorescence assay. Mizoribine, a well-known inhibitor of Hsp60, attenuated both Pf-calpain enzyme activity as well as P. falciparum growth. The presented data suggest that the Pf-Hsp60 may function on Pf-calpain in a part of networks during malaria growth.
Amino Acid Sequence ; Calpain/genetics/*metabolism ; Chaperonin 60/chemistry/genetics/*metabolism ; Erythrocytes/parasitology ; Humans ; Malaria, Falciparum/parasitology ; Molecular Sequence Data ; Plasmodium falciparum/chemistry/enzymology/genetics/*metabolism ; Protein Binding ; Protozoan Proteins/chemistry/genetics/*metabolism ; Sequence Alignment

The parasite Plasmodium falciparum causes severe malaria and is the most dangerous to humans. However, it exhibits resistance to their drugs. Farnesyltransferase has been identified in pathogenic protozoa of the genera Plasmodium and the target of farnesyltransferase includes Ras family. Therefore, the inhibition of farnesyltransferase has been suggested as a new strategy for the treatment of malaria. However, the exact functional mechanism of this agent is still unknown. In addition, the effect of farnesyltransferase inhibitor (FTIs) on mitochondrial level of malaria parasites is not fully understood. In this study, therefore, the effect of a FTI R115777 on the function of mitochondria of P. falciparum was investigated experimentally. As a result, FTI R115777 was found to suppress the infection rate of malaria parasites under in vitro condition. It also reduces the copy number of mtDNA-encoded cytochrome c oxidase III. In addition, the mitochondrial membrane potential (DeltaPsim) and the green fluorescence intensity of MitoTracker were decreased by FTI R115777. Chloroquine and atovaquone were measured by the mtDNA copy number as mitochondrial non-specific or specific inhibitor, respectively. Chloroquine did not affect the copy number of mtDNA-encoded cytochrome c oxidase III, while atovaquone induced to change the mtDNA copy number. These results suggest that FTI R115777 has strong influence on the mitochondrial function of P. falciparum. It may have therapeutic potential for malaria by targeting the mitochondria of parasites.
Antimalarials/*pharmacology ; Enzyme Inhibitors/*pharmacology ; Farnesyltranstransferase/*antagonists & inhibitors/genetics/*metabolism ; Humans ; Malaria, Falciparum/drug therapy/*parasitology ; Mitochondria/*drug effects/metabolism ; Plasmodium falciparum/drug effects/*enzymology/genetics ; Protozoan Proteins/*antagonists & inhibitors/genetics/metabolism ; Quinolones/*pharmacology

The present study determined and compared the genetic diversity of Plasmodium falciparum strains infecting children living in 2 areas from Gabon with different malaria endemicity. Blood samples were collected from febrile children from 2008 to 2009 in 2 health centres from rural (Oyem) and urban (Owendo) areas. Genetic diversity was determined in P. falciparum isolates by analyzing the merozoite surface protein-1 (msp1) gene polymorphism using nested-PCR. Overall, 168 children with mild falciparum malaria were included. K1, Ro33, and Mad20 alleles were found in 110 (65.5%), 94 (55.9%), and 35 (20.8%) isolates, respectively, without difference according to the site (P>0.05). Allelic families' frequencies were comparable between children less than 5 years old from the 2 sites; while among the older children the proportions of Ro33 and Mad20 alleles were 1.7 to 2.0 fold higher at Oyem. Thirty-three different alleles were detected, 16 (48.5%) were common to both sites, and 10 out of the 17 specific alleles were found at Oyem. Furthermore, multiple infection carriers were frequent at Oyem (57.7% vs 42.2% at Owendo; P=0.04) where the complexity of infection was of 1.88 (+/-0.95) higher compared to that found at Owendo (1.55+/-0.75). Extended genetic diversity of P. falciparum strains infecting Gabonese symptomatic children and high multiplicity of infections were observed in rural area. Alleles common to the 2 sites were frequent; the site-specific alleles predominated in the rural area. Such distribution of the alleles should be taken into accounts when designing MSP1 or MSP2 malaria vaccine.
Child ; Child, Preschool ; Female ; Gabon ; *Gene Frequency ; Genetic Variation ; Genotype ; Humans ; Infant ; Malaria, Falciparum/*parasitology ; Male ; Merozoite Surface Protein 1/*genetics/metabolism ; Plasmodium falciparum/*genetics/metabolism ; Protozoan Proteins/*genetics/metabolism ; Rural Population ; Urban Population