Genetic Diversity and Population Genetic Analysis of Plasmodium falciparum Thrombospondin Related Anonymous Protein (TRAP) in Clinical Samples from Saudi Arabia

The thrombospondin related anonymous protein (TRAP) is considered one of the most important pre-erythrocytic vaccine targets. Earlier population genetic studies revealed the TRAP gene to be under strong balancing natural selection. This study is the first attempt to analyze genetic diversity, natural selection, phylogeography and population structure in 199 clinical samples from Saudi Arabia using the full-length PfTRAP gene. We found the rate of nonsynonymous substitutions to be significantly higher than that of synonymous substitutions in the clinical samples, indicating a strong positive or diversifying selection for the full-length gene and the Von Willebrand factor (VWF). The nucleotide diversity was found to be π~0.00789 for the full-length gene; however, higher nucleotide diversity was observed for the VWF compared to the thrombospondin repeat region (TSP). Deduction of the amino acid sequence alignment of the PNP repeat region in the Saudi samples revealed six genotypes characterized by tripeptide repeat motifs (PNP, ANP, ENP and SNP). Haplotype network, population structure and population differentiation analyses indicated four distinct sub-populations in spite of the low geographical distance between the sampling sites. Our results suggest the likeliness of independent parasite evolution, creating opportunities for further adaptation, including host transition, and making malaria control even more challenging

Scanning Electron Microscopical Studies on Schistosoma mansoni cercariae Exposed to Ultraviolet Irradiation

Abstract: In the present work, scanning electron microscopical studies on Schistosoma mansoni cercariae exposed to ultraviolet irradiation (UV-irradiation) were done to answer the question: Is the damage inflicted seen on the adult schistosome worms developed from irradiated cercariae, due to direct effect of UV-irradiation on cercariae or due to the host's immunogenicity induced by UVirradiated cercariae? The present observations showed that there were no changes on the surface topography of S. mansoni cercariae exposed to UV-irradiation. Thus we can suggest that the changes seen in the adult worm developed from UV-irradiated cercariae may be due to the immune responses of the host induced by attenuated cercariae; or it may be due to the mutagenic effects of the UVradiation which appeared in the adult stages. Detailed discussion on the scope of the recent knowledge about the immunological aspects due to irradiated cercariae was presented

Taxonomic justification of the pathogenic strongylid infecting the Arabian camel Camelus dromedarius as Haemonchus longistipes by morphological and molecular phylogeny

Introduction: There is still lack of morphological and phylogenetic information on the pathogenic nematode of the camel Haemonchus longistipes. In the present study, this parasite was isolated in Saudi Arabia and described

Bivagina pagrosomi Murray (1931) (Monogenea: Polyopisthocotylea), a microcotylid infecting the gills of the gilt-head sea bream Sparus aurata (Sparidae) from the Red Sea: morphology and phylogeny

Monogenea is a class of ectoparasitic flatworms on the skin, gills, or fins of fish. Microcotylidae is a family of polyopisthocotylean monogeneans parasitising only marine fishes. This work describes and taxonomically determines a microcotylid polyopisthocotylean monogenean in an important fish in Saudi aquaculture

Light microscopy and surface topography of Urotrema scabridum and Renschetrema indicum (Digenea) from Rhinopoma hardwickii (Chiroptera): first report in Egypt

Abstract This report introduced the description of two different species of digenean parasites isolated from the intestine of Rhinopoma hardwickii with new host and locality records in Egypt. The recovered helminthes were studied morphologically and morphometrically by light microscopy and the surface topography of the two species was elucidated by scanning electron microscopy (SEM). Urotrema scabridum had an elongated body, testes were tandem, ovaries were pretesticular, and vitelline follicles were observed in 2 lateral fields. SEM showed that the anterior half was covered with random and backwardly directed tegument spines. The lumen of the oral sucker was as a longitudinal slit encircled with type I dome-shaped papillae. The ventral sucker was wrinkled and covered by tongue-shaped tegument spines and several scattered papillae. Renschetrema indicum had a fusiform body with minute spines densely distributed in the anterior part of the body; testes sub-triangular, ovary fusiform; vitellaria were randomly distributed around the ceca and genital organs. SEM showed that the fore-body was ventrally concave and surrounded by cytoplasmic ridges equipped with numerous closely packed claw-shaped spines. The oral sucker was externally surrounded by two circles of papillae while the lip of the ventral sucker was rounded and surrounded by three papillae located in its upper end and anterolaterally

Development of species-specific primers for identification of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia

AbstractSchistosoma mansoni is mediated through the intermediate host Biomphalaria arabica which lives in Saudi Arabia. Molecular characterization and identification of this intermediate host are important for epidemiological studies of schistosomiasis. The present work aimed to determine the molecular variations among the populations of B. arabica found in Southern part of Saudi Arabia, and to develop species-specific primers for identification of these snails as a first step in the development of multiplex PCR for simultaneously identifying the snails and diagnosing its infections in a single step. Five populations of Saudi B. arabica snails were collected from freshwater bodies. Three populations were collected from Asser and two populations were collected from AL-Baha. Genomic DNA was extracted from snails and was amplified using five different RAPD–PCR primers. The banding patterns of amplified materials by primers P1 and P5 were identical in all populations. However, the rest primers displayed intra-specific differences among populations with variable degrees. Largest sizes of RAPD–PCR products were cloned into TA cloning vector as a preparatory step for DNA sequence analysis. After sequencing, similarity searches of obtained DNA sequences revealed that there are no similar sequences submitted to genebank data bases and its associated banks. The results obtained will be helpful in the development of simultaneous identification of B. arabica snails and diagnosis of S. mansoni infection within it in a single step by an implementation of multiplex PCR

Interleukin-22 Polymorphisms in Plasmodium falciparum-Infected Malaria Patients

Background and Objectives. Malaria infection, caused by Plasmodium falciparum, is the most lethal and frequently culminates in severe clinical complications. Interleukin-22 (IL-22) has been implicated in several diseases including malaria. The objective of this study was to investigate the role of IL-22 gene polymorphisms in P. falciparum infection. Material and Methods. Ten single-nucleotide polymorphisms (SNPs), rs976748, rs1179246, rs2046068, rs1182844, rs2227508, rs2227513, rs2227478, rs2227481, rs2227491, and rs2227483, of IL-22 gene were genotyped through PCR-based assays of 250 P. falciparum-infected patients and 200 healthy controls. In addition, a luciferase reporter assay was done to assess the role of the rs2227513 SNP in IL-22 gene promoter activity. Results. We found that the rs2227481 TT genotype (odds ratio 0.254, confidence interval = 0.097-0.663, P=0.002) and the T allele is associated with protection against P. falciparum malaria as well as the rs2227483 AT genotype (odds ratio 0.375, confidence interval = 0.187-0.754, P=0.004). The haplotype A-T-T of rs1179246, rs1182844, and rs976748 was statistically more frequent in the control group (frequency 41%, P=0.034) as well as the haplotype A-G of rs2046068 and rs2227491 (frequency 49.4%, P=0.041). The variant rs2227513 G allele had a statistically higher activity (P<0.0001) with the luciferase reporter assay. Conclusion. The study suggests that IL-22 polymorphisms in rs2227481 and rs2227483 could contribute to protection against P. falciparum malaria. Also, the G allele of rs2227513, located in the promoter region of IL-22 gene, could be essential for higher expression levels of IL-22 cytokine