Hesam Barjesteh | PubMed Health

PubMed2006

Merozoite surface protein-3alpha is a reliable marker for population genetic analysis of Plasmodium vivax.

BACKGROUND: The knowledge on population structure of the parasite isolates has contributed greatly to understanding the dynamics of the disease transmission for designing and evaluating malaria vaccines as well as for drug applications. msp-1 and msp-3alpha genes have been used as a genetic marker in population studies of Plasmodium vivax isolates. In this study, msp-3alpha was compared and assessed with msp-1 marker in order to find whether msp-3alpha is a reliable genetic marker for P. vivax population studies. METHODS: This comparative study was designed and carried out as the first assessment of diversity in Pvmsp-3alpha gene by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in the 50 northern and 94 southern P. vivax isolates from Iran, which had been analysed before for msp-1 gene. RESULTS: Three allele size as, Type A (1.8 kb), Type B (1.5 kb) and Type C (1.2 kb) have been detected among both northern and southern isolates based on PCR results. Type C (70%) and Type A (68.7%) were the predominant fragments among northern and southern parasites, respectively. 99 distinct Pvmsp-3alpha fragments defined by the size were detected in the 94 southern samples by PCR analysis. However, no mixed genotype infections have been detected among northern isolates. Based on restriction pattern from digestion with Hha I and Alu I 12 and 49 distinct allelic variants have been detected among 50 northern and 94 southern isolates. However, based on msp-1 gene, 30 distinct variants identified in all 146-sequenced Iranian P. vivax isolate. CONCLUSION: The results suggested that PCR-RFLP on msp-3alpha gene is an adequate, applicable and easily used technique for molecular epidemiology studies of P. vivax isolates without the need for further sequencing analysis.

Alleles↗

PubMed2006

Identification, sequence analysis, and comparative study on GSTe2 insecticide resistance gene in three main world malaria vectors: Anopheles stephensi, Anopheles culicifacies, and Anopheles fluviatilis.

Glutathione S-transferases (GSTs) are soluble dimeric proteins that are involved in the metabolism, detoxification, and excretion of a large number of endogenous and exogenous compounds such as insecticides from the cell. In the current study, field specimens of Anopheles stephensi Liston, Anopheles fluviatilis James, and Anopheles culicifacies Giles collected from Sistan and Baluchistan province in Iran and subjected to World Health Organization susceptibility test. Only An. stephensi was resistant to 4% DDT. DNA extraction and rDNA-ITS2-polymerase chain reaction (PCR) for correct species identification, followed by amplification of GSTe2 gene, including exon I and II and full sequence of intron I, identified a 500-bp fragment in these three species. These fragments were purified and sequenced from both ends. The comparison of coding sequence of GSTe2 gene between these species and with Anopheles gambiae Giles showed 82 to 86% similarity at nucleic acid levels and identified nucleotide polymorphisms within An. culicifacies and An. stephensi populations. Species-specific differences have been detected in intron I of GSTe2 gene. This is in concordance with the previous studies and confirmed the conserved nature of intron sequence in GSTe2 gene of each species, probably useful as a molecular marker for species-specific identification. Phylogenetic analysis based on rDNA-ITS2, and coding (exon I and II) and noncoding sequences of GSTe2, showed the systematic relatedness between Iranian malaria vectors and the possibility of using these sequences in both differentiation of Anopheles species and defining their evolutionary relationship with the only available GSTe2 sequence of An. gambiae. These data may be useful for implementation and evaluation of malaria control programs in aspects of population genetics and molecular resistance.

Animals↗