PURPOSE: Although the polymorphisms of erythrocyte complement receptor type 1 (CR1) in patients with malaria have been extensively studied, a question of whether the polymorphisms of CR1 are associated with severe malaria remains controversial. Furthermore, no study has examined the association of CR1 polymorphisms with malaria in Chinese population. Therefore, we investigated the relationship of CR1 gene polymorphism and malaria in Chinese population. MATERIALS AND METHODS: We analyzed polymorphisms of CR1 gene rs2274567 G/A, rs4844600 G/A, and rs2296160 C/T in 509 patients with malaria and 503 controls, using the Taqman genotyping assay and PCR-direct sequencing. RESULTS: There were no significant differences in the genotype, allele and haplotype frequencies of CR1 gene rs2274567 G/A, rs4844600 G/A, and rs2296160 C/T polymorphisms between patients with malaria and controls. Furthermore, there was no association of polymorphisms in the CR1 gene with the severity of malaria in Chinese population. CONCLUSION: These findings suggest that CR1 gene rs2274567 G/A, rs4844600 G/A, and rs2296160 C/T polymorphisms may not be involved in susceptibility to malaria in Chinese population.
Adult ; Alleles ; Asian Continental Ancestry Group ; Case-Control Studies ; China ; Erythrocytes/parasitology ; Female ; Genetic Predisposition to Disease ; Genotype ; *Haplotypes ; Humans ; Malaria/ethnology/*genetics ; Male ; Middle Aged ; Polymorphism, Single Nucleotide/*genetics ; Promoter Regions, Genetic/*genetics ; Receptors, Complement/blood/*genetics ; Taq Polymerase

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

Rodent malaria parasites, such as Plasmodium berghei, are practical and useful model organisms for human malaria research because of their analogies to the human malaria in terms of structure, physiology, and life cycle. Exploiting the available genetic sequence information, we constructed a cDNA library from the erythrocytic stages of P. berghei and analyzed the expressed sequence tag (EST). A total of 10,040 ESTs were generated and assembled into 2,462 clusters. These EST clusters were compared against public protein databases and 48 putative new transcripts, most of which were hypothetical proteins with unknown function, were identified. Genes encoding ribosomal or membrane proteins and purine nucleotide phosphorylases were highly abundant clusters in P. berghei. Protein domain analyses and the Gene Ontology functional categorization revealed translation/protein folding, metabolism, protein degradation, and multiple family of variant antigens to be mainly prevalent. The presently-collected ESTs and its bioinformatic analysis will be useful resources to identify for drug target and vaccine candidates and validate gene predictions of P. berghei.
Animals ; Computational Biology ; Erythrocytes/*parasitology ; *Expressed Sequence Tags ; *Gene Expression Profiling ; Mice ; Mice, Inbred C57BL ; Plasmodium berghei/*genetics/*pathogenicity

Babesia spp. were detected from 4 asymptomatic pukus captured on a game ranch in central Zambia in October 2008. Blood smears were examined in 4 species of aymptomatic free-ranging antelopes, namely the puku (Kobus vordanii), reedbuck (Redunca arundinum), bushbuck (Tragelaphus sylvaticus), and kudu (Tragelaphus strepsiceros), and showed the presence of Babesia parasites only in the puku. In the puku, the prevalence of babesiosis was estimated at 33.3% (n=12), while the overall prevalence in all examined animals was 8.5% (n=47). The parasites showed morphological characteristics of paired ring-like stages with the length varying between 1.61 microm and 3.02 microm (mean=2.12 microm, n=27; SD=0.76 microm). Both the infected and non-infected pukus showed good body condition scores (BCS), while the dominant tick species detected from all animals were Rhipicephalus appendiculatus, Rhipicephalus spp., and Boophilus spp. To our knowledge this is the first report of Babesia spp. infection in pukus in Zambia. These findings suggest that wildlife could play an important role in the epidemiology of babesiosis in Zambia.
Animals ; Animals, Wild/parasitology ; Antelopes/*parasitology ; Arachnid Vectors/classification ; Asymptomatic Diseases ; Babesia/*isolation & purification/ultrastructure ; Babesiosis/epidemiology/transmission/*veterinary ; Erythrocytes/parasitology ; Prevalence ; Rhipicephalus/classification ; Tick Infestations/epidemiology/parasitology/veterinary ; Ticks/parasitology ; Zambia/epidemiology

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Erythrocytes/parasitology ; Female ; Humans ; Malaria, Vivax/*diagnosis/epidemiology/parasitology ; Male ; Middle Aged ; Parasitemia/*diagnosis/epidemiology/parasitology ; Plasmodium vivax/isolation & purification ; Republic of Korea/epidemiology

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Erythrocytes/parasitology ; Female ; Humans ; Malaria, Vivax/*diagnosis/epidemiology/parasitology ; Male ; Middle Aged ; Parasitemia/*diagnosis/epidemiology/parasitology ; Plasmodium vivax/isolation & purification ; Republic of Korea/epidemiology

Malarial infection is one of the most important tropical diseases, but also increasing in the temperate regions. Severe malaria with organ dysfunction is commonly associated with Plasmodium falciparum, but rarely with Plasmodium vivax. Malarial hepatitis is also unusual in P. falciparum and very rare in P. vivax. Only 3 cases of malarial hepatitis caused by P. vivax have been reported in the world. Because the presence of hepatitis in malaria indicates a more severe illness with higher incidence of other complications and poor prognosis, malarial patients should be meticulously monitored for hepatic dysfunction with or without jaundice. We report here a case of malarial hepatitis caused by P. vivax that was presented by fever, general ache, nausea, fatigue, and significant elevation of aminotransferase and bilirubin.
Abdomen/ultrasonography ; Antimalarials/therapeutic use ; Erythrocytes/immunology/parasitology ; Fatigue/etiology ; Hepatitis/*diagnosis/etiology/ultrasonography ; Humans ; Malaria, Vivax/complications/*diagnosis/drug therapy ; Male ; Mefloquine/therapeutic use ; Nausea/etiology ; Plasmodium vivax/isolation & purification ; Primaquine/therapeutic use ; Young Adult

Malaria parasites adapt to the oxidative stress during their erythrocytic stages with the help of vital thioredoxin redox system and glutathione redox system. Glutathione reductase and thioredoxin reductase are important enzymes of these redox systems that help parasites to maintain an adequate intracellular redox environment. In the present study, activities of glutathione reductase and thioredoxin reductase were investigated in normal and Plasmodium berghei-infected mice red blood cells and their fractions. Activities of glutathione reductase and thioredoxin reductase in P. berghei-infected host erythrocytes were found to be higher than those in normal host cells. These enzymes were mainly confined to the cytosolic part of cell-free P. berghei. Full characterization and understanding of these enzymes may promise advances in chemotherapy of malaria.
Animals ; Antioxidants/*isolation & purification/*metabolism ; Cell Fractionation ; Cytosol/enzymology ; Erythrocytes/parasitology ; Glutathione Reductase/*isolation & purification/*metabolism ; Mice ; Plasmodium berghei/*enzymology ; Thioredoxin-Disulfide Reductase/*isolation & purification/*metabolism

Differences in the characteristics of the culture conditions can influence the multiplication rate of Plasmodium falciparum. The Petri dish method is one of the most popular methods of cultivating this parasite. In many previous studies, ideal culture conditions of the Petri dish method were achieved by using erythrocytes collected from blood that had been stored for at least 2 weeks, with daily changes of the medium. In the present study, we studied the multiplication rate of P. falciparum in cultures containing erythrocytes of various ages together with changing the medium at various intervals of time. Our results strongly suggest that the rate of in vitro multiplication of P. falciparum was higher in freshly collected erythrocytes than in aged erythrocytes regardless of the anticoagulant and that when the parasitemia is lower than 8% with a hematocrit of 5%, the medium change interval can be as long as 48 hr without a great reduction in the rate of multiplication.
Animals ; Blood Specimen Collection ; Cell Aging ; Culture Media ; Erythrocytes/*parasitology ; Plasmodium falciparum/*growth & development ; Time Factors

The present study evaluated the effects of infected culture supernatant of erythrocytes, fractionation of culture supernatant and serum from dogs infected with Babesia gibsoni (B. gibsoni) on the maturation of canine reticulocytes in vitro. The SDS-PAGE demonstrated that significantly broader bands were generated by both the infected culture supernatant of erythrocytes and the serum from dogs chronically infected with B. gibsoni. The culture supernatant of erythrocytes infected with B. gibsoni strongly suppressed the maturation of reticulocytes. Prior studies showed that chronically infected serum had inhibitory effects on both the maturation of reticulocytes and the canine pyrimidine 5'-nucleotidase subclass I and purine-specific 5'-nucleotidase activity. In addition, serum free infected culture supernatant of erythrocytes had an inhibitory effect on the morphological maturation of reticulocytes. These results suggest that infected serum and culture supernatant of erythrocytes might accumulate excess proteins and/or metabolites as a result of the inhibited maturation of reticulocytes and decreased activity of erythrocyte 5'-nucleotidase. Furthermore, the fractions observed at >150 kDa- and 150-70 kDa- in the infected culture supernatant and serum retarded the maturation of canine reticulocytes in vitro. The results obtained from the in vitro examinations, in the present study, suggested that B. gibsoni itself and/or its metabolites might release certain proteins in the infected culture supernatant and serum from infected dogs and as a result delay morphological maturation of canine reticulocytes.
Animals ; Babesia/*immunology ; Babesiosis/blood/immunology/parasitology/*veterinary ; Cell Differentiation/immunology ; Dog Diseases/*blood/immunology/*parasitology ; Dogs ; Electrophoresis, Polyacrylamide Gel ; Erythrocytes/*immunology ; Reticulocytes/*immunology