Variable number of tandem repeats of 9 Plasmodium vivax genes among Southeast Asian isolates

The variable number of tandem repeats (VNTRs) provides valuable information about both the functional and evolutionary aspects of genetic diversity. Comparative analysis of 3 Plasmodium falciparum genomes has shown that more than 9% of its open reading frames (ORFs) harbor VNTRs. Although microsatellites and VNTR genes of P. vivax were reported, the VNTR polymorphism of genes has not been examined widely. In this study, 230 P. vivax genes were analyzed for VNTRs by SERV, and 33 kinds of TR deletions or insertions from 29 P. vivax genes (12.6%) were found. Of these, 9 VNTR fragments from 8 P. vivax genes were used for PCR amplification and sequence analysis to examine the genetic diversity among 134 isolates from four Southeast Asian countries (China, Republic of Korea, Thailand, and Myanmar) with different malaria endemicity. We confirmed the existence of extensive polymorphism of VNTR fragments in field isolates. This detection provides several suitable markers for analysis of the molecular epidemiology of P. vivax field isolates.

Properties of 137Cs in marine sediments off Yangnam, Korea

Concentrations of 137Cs in sediment and seawater samples in the East Sea (Japan Sea) adjacent to Yangnam, Korea were measured and data on the physical and chemical properties of the sediments were collected. The concentrations of 137Cs in the sediment samples were in the range of less than the minimum detectable activity (MDA)-7.19 Bq/kg-dry, and the values were linearly correlated with particle size, total organic carbon (TOC), H, N or S content of the sediment. The 137Cs concentrations in the sediment samples were well fitted to a multiple regression equation with TOC contents and particle size distributions. The distribution coefficients, which indicate the degree of adsorption, of 137Cs to the sediments were strongly dependent on particle size and TOC content.

Analysis of the VNTR locus DXS52 by the Amp-FLP technique

The locus DXS52 is useful genetic marker system for forensic analysis. It consists of a variable number of tandem repeats (VNTR) and can be analyzed by the Amp-FLP technique. As accurate data about the distribution of the alleles are among the most important prerequisites for the application in forensic biology, we studied the allele distribution of DXS52 locus in a Chinese population and applied the established technique to paternity testing.