Conserved Plasmodium Protein (PF3D7_0406000) of Unknown Function: In-silico Analysis and Cellular Localization.

In spite of a decrease in malaria cases, the threat of malaria due to Plasmodium falciparum still prevails. The sequencing of Plasmodium falciparum reveals that approximately 60% of the Plasmodium genes code for hypothetical/putative proteins. Here we report an in silico characterization and localization of one such protein. This was encoded by one of the hub genes, in a weighted gene co-expression based systems network, from in-vivo samples of patients suffering from uncomplicated malaria or complicated malaria disease like jaundice and jaundice with renal failure. Interestingly, the protein PF3D7_0406000 (PFD0300w) is classified as a conserved protein of unknown function and shows no identity with any protein from the human host. The transcriptomic data shows up-regulation of transcripts in cases of malaria induced disease complications. PFD0300w peptide antibody based immunolocalization studies using a, gametocyte producing P. falciparum strain RKL-9, shows presence of the protein in the cytoplasm of both asexual and sexual stage parasites.

Compound Heterozygosity of ß-Thalassemia and the Sickle Cell Hemoglobin in Various Populations of Chhattisgarh State, India.

Hemoglobinopathies evolved as a protective mechanism against malaria, which exhibit selective advantage in the heterozygous state. However, in a homozygous recessive condition, it poses a serious socioeconomic burden. Sickle cell anemia is an autosomal recessive hemoglobinopathy associated with erythrocytes sickling, vaso-occlusive crisis (VOC), as well as multi-organ failure and death. The coinheritance of other hemoglobinopathies is known to substantially modulate the clinical manifestation of sickle cell anemia. In the present study, we aimed to analyze the coinheritance of ß-thalassemia (ß-thal) in Hb S (HBB: c.20A>T) patients. The study includes 918 sickle cell anemia patients from 10 ethnic populations of Chhattisgarh State, India. Complete blood counts (CBCs) and hemoglobin (Hb) high performance liquid chromatography (HPLC) fractionation data were collected from patient record books. We observed Hb S-ß-thal in all the analyzed populations. Interestingly, high frequencies of Hb S-ß-thal have been observed in Satnami (53.8%), Rawat (47.1%), Gond (35.1%) and Panika (30.6%) populations. Inter-population comparison of hematological parameters [Hb F (p < 0.001), Hb A2 (p < 0.001), Hb (p = 0.03) and red blood cell distribution width (RDW) (p < 0.001)] revealed significant differences. We also observed that mean Hb F levels were significantly higher in Hb S compared to Hb S-ß-thal patients in the respective populations. Our study highlights the higher prevalence of ß-thal as well as the compound heterozygosity for Hb S and ß-thal in various populations of Chhattisgarh State, India.

Disease specific modules and hub genes for intervention strategies: A co-expression network based approach for Plasmodium falciparum clinical isolates.

Systems biology approaches that are based on gene expression and bioinformatics analysis have been successful in predicting the functions of many genes in Plasmodium falciparum, a protozoan parasite responsible for most of the deaths due to malaria. However, approaches that can provide information about the biological processes that are active in this parasite in vivo during complicated malaria conditions have been scarcely deployed. Here we report the analysis of a weighted gene co-expression based network for P. falciparum, from non-cerebral clinical complications. Gene expression profiles of 20 P. falciparum clinical isolates were utilized to construct the same. A total of 20 highly interacting modules were identified post network creation. In 12 of these modules, at least 10% of the member genes, were found to be differentially regulated in parasites from patient isolates showing complications, when compared with those from patients with uncomplicated disease. Enrichment analysis helped identify biological processes like oxidation-reduction, electron transport chain, protein synthesis, ubiquitin dependent catabolic processes, RNA binding and purine nucleotide metabolic processes as associated with these modules. Additionally, for each module, highly connected hub genes were identified. Detailed functional analysis of many of these, which have known annotated functions underline their importance in parasite development and survival. This suggests, that other hub genes with unknown functions may also be playing crucial roles in parasite biology, and, are potential candidates for intervention strategies.

Plasmodium falciparum complicated malaria: Modulation and connectivity between exportome and variant surface antigen gene families.

In temperate and sub-tropical regions of Asia and Latin America, complicated malaria manifested as hepatic dysfunction or renal dysfunction is seen in all age groups. There has been a concerted focus on understanding the patho-physiological and molecular basis of complicated malaria in children, much less is known about it in adults. We report here, the analysis of data from a custom, cross strain microarray (Agilent Platform) using material from adult patient samples, showing hepatic dysfunction or renal failure. These are the most common manifestations seen in adults along with cerebral malaria. The data has been analyzed with reference to variant surface antigens, encoded by the var, rifin and stevor gene families. The differential regulation profiles of key genes (comparison between Plasmodium falciparum complicated and uncomplicated isolates) have been observed. The exportome has been analyzed using similar parameters. Gene ontology term based functional enrichment of differentially regulated genes identified, up-regulated genes statistically enriched (P<0.05) to critical biological processes like generation of precursor metabolite and energy, chromosome organization and electron transport chain. Systems network based functional enrichment of overall differentially regulated genes yielded a similar result. We are reporting here, up-regulation of var group B and C genes whose proteins are predicted to interact with CD36 receptor in the host, the up-regulation of domain cassette 13 (DC13) containing var group A, as also the up-regulation of group A rifins and many of the stevors. This is contrary to most other reports from pediatric patients, with cerebral malaria where the up-regulation of mostly var A group genes have been seen. A protein-protein interaction based network has been created and analysis performed. This co-expression and text mining based network has shown overall connectivity between the variant surface antigens (VSA) and the exportome. The up-regulation of var group B and C genes encoding PfEMP1 with different domain architecture would be important for deciding strategies for disease prevention.