Synergy of Omeprazole and Praziquantel In Vitro Treatment against Schistosoma mansoni Adult Worms.

BACKGROUND: Treatment and morbidity control of schistosomiasis relies on a single drug, praziquantel (PZQ), and the selection of resistant worms under repeated treatment is a concern. Therefore, there is a pressing need to understand the molecular effects of PZQ on schistosomes and to investigate alternative or synergistic drugs against schistosomiasis. METHODOLOGY: We used a custom-designed Schistosoma mansoni expression microarray to explore the effects of sublethal doses of PZQ on large-scale gene expression of adult paired males and females and unpaired mature females. We also assessed the efficacy of PZQ, omeprazole (OMP) or their combination against S. mansoni adult worms with a survival in vitro assay. PRINCIPAL FINDINGS: We identified sets of genes that were affected by PZQ in paired and unpaired mature females, however with opposite gene expression patterns (up-regulated in paired and down-regulated in unpaired mature females), indicating that PZQ effects are heavily influenced by the mating status. We also identified genes that were similarly affected by PZQ in males and females. Functional analyses of gene interaction networks were performed with parasite genes that were differentially expressed upon PZQ treatment, searching for proteins encoded by these genes whose human homologs are targets of different drugs used for other diseases. Based on these results, OMP, a widely prescribed proton pump inhibitor known to target the ATP1A2 gene product, was chosen and tested. Sublethal doses of PZQ combined with OMP significantly increased worm mortality in vitro when compared with PZQ or OMP alone, thus evidencing a synergistic effect. CONCLUSIONS: Functional analysis of gene interaction networks is an important approach that can point to possible novel synergistic drug candidates. We demonstrated the potential of this strategy by showing that PZQ in combination with OMP displayed increased efficiency against S. mansoni adult worms in vitro when compared with either drug alone.

Sequencing of simple sequence repeat anchored polymerase chain reaction amplification products of Biomphalaria glabrata.

Simple sequence repeat anchored polymerase chain reaction amplification (SSR-PCR) is a genetic typing technique based on primers anchored at the 5' or 3' ends of microsatellites, at high primer annealing temperatures. This technique has already been used in studies of genetic variability of several organisms, using different primer designs. In order to conduct a detailed study of the SSR-PCR genomic targets, we cloned and sequenced 20 unique amplification products of two commonly used primers, CAA(CT)6 and (CA)8RY, using Biomphalaria glabrata genomic DNA as template. The sequences obtained were novel B. glabrata genomic sequences. It was observed that 15 clones contained microsatellites between priming sites. Out of 40 clones, seven contained complex sequence repetitions. One of the repeats that appeared in six of the amplified fragments generated a single band in Southern analysis, indicating that the sequence was not widespread in the genome. Most of the annealing sites for the CAA(CT)6 primer contained only the six repeats found within the primer sequence. In conclusion, SSR-PCR is a useful genotyping technique. However, the premise of the SSR-PCR technique, verified with the CAA(CT)6 primer, could not be supported since the amplification products did not result necessarily from microsatellite loci amplification.

Sequencing of simple sequence repeat anchored polymerase chain reaction amplification products of Biomphalaria glabrata

Simple sequence repeat anchored polymerase chain reaction amplification (SSR-PCR) is a genetic typing technique based on primers anchored at the 5' or 3' ends of microsatellites, at high primer annealing temperatures. This technique has already been used in studies of genetic variability of several organisms, using different primer designs. In order to conduct a detailed study of the SSR-PCR genomic targets, we cloned and sequenced 20 unique amplification products of two commonly used primers, CAA(CT)6 and (CA)8RY, using Biomphalaria glabrata genomic DNA as template. The sequences obtained were novel B. glabrata genomic sequences. It was observed that 15 clones contained microsatellites between priming sites. Out of 40 clones, seven contained complex sequence repetitions. One of the repeats that appeared in six of the amplified fragments generated a single band in Southern analysis, indicating that the sequence was not widespread in the genome. Most of the annealing sites for the CAA(CT)6 primer contained only the six repeats found within the primer sequence. In conclusion, SSR-PCR is a useful genotyping technique. However, the premise of the SSR-PCR technique, verified with the CAA(CT)6 primer, could not be supported since the amplification products did not result necessarily from microsatellite loci amplification