Genetic analysis of the merozoite surface protein-1 block 2 allelic types in Plasmodium falciparum clinical isolates from Lao PDR

<p>Abstract</p> <p>Background</p> <p>MSP-1 is one of the potential malarial vaccine candidate antigens. However, extensive genetic polymorphism of this antigen in the field isolates of <it>Plasmodium falciparum </it>represents a major hindrance for the development of an effective vaccine. Therefore, this study aimed to establish the prevalence and genetic polymorphisms of K1, MAD20 and RO33 allelic types of <it>msp-1 </it>block 2 among <it>P. falciparum </it>clinical isolates from Lao PDR.</p> <p>Methods</p> <p><it>Plasmodium falciparum </it>isolates were collected from 230 <it>P. falciparum</it>-infected blood samples from three regions of Lao PDR. K1, MAD20 and RO33 were detected by nested PCR; SSCP was used for polymorphism screening. The nested PCR products of each K1, MAD20 and RO33 allelic types that had different banding patterns by SSCP, were sequenced.</p> <p>Results</p> <p>The overall prevalence of K1, MAD20 and RO33 allelic types in <it>P. falciparum </it>isolates from Lao PDR were 66.95%, 46.52% and 31.30%, respectively, of samples under study. Single infections with K1, MAD20 and RO33 allelic types were 27.83%, 11.74% and 5.22%, respectively; the remainders were multiple clonal infections. Neither parasite density nor age was related to MOI. Sequence analysis revealed that there were 11 different types of K1, eight different types of MAD20, and 7 different types of RO33. Most of them were regional specific, except type 1 of each allelic type was common found in 3 regions under study.</p> <p>Conclusions</p> <p>Genetic polymorphism with diverse allele types was identified in <it>msp-1 </it>block 2 among <it>P</it>. <it>falciparum </it>clinical isolates in Lao PDR. A rather high level of multiple clonal infections was also observed but the multiplicity of infection was rather low as not exceed 2.0. This basic data are useful for treatment and malaria control program in Lao PDR.</p

Agronomic properties and heavy metals content in soil reclaimed from municipal solid waste landfill development of a knowledge-based system for foundry waste recycling

Landfill soils reclaimed from municipal solid waste landfill were characterized for agronomic properties and heavy metals. The samples were collected from Khon Kaen Municipality engineered landfill, Khon Kaen, Thailand, approximately aged 10-15 years, and screened with a 6.3-mm sieve. Chemical properties analysis was undertaken by appropriate procedure, and heavy metals were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). The landfill soil characteristics measured include pH, electrical conductivity (EC), cation exchange capacity (CEC), organic matter (OM), total N, available P, K, Mg and Ca; results obtained were 8.1, 4.2 dS/m, 4.4 cmol/kg, 4.9%, 0.27%, 23.2 mg/kg, 1.24 g/kg, 10.5 g/kg and 0.43 g/kg, respectively. The heavy metal contents in landfill soil included 2.0 As, 3.25 Cd, 3.3 Co, 38.0 Cr, 166.0 Cu, 1533.0 Fe, 0.72 Hg, 412 Mn, 22.0 Ni, 157.0 Pb, 1.0 Se, 44.0 Sn and 662 Zn mg/kg, respectively. These heavy metal concentrations were within permissible limits for land application described by Thailand and US EPA. This result indicated that municipal solid waste landfill had potential for recovery soil, and its use for soil amendment