No abstract

A 70-mer oligonucleotide-based microarray (1152 features) that emphasizes stress and immune responses factors was constructed to study transcriptomic responses of the snail Biomphalaria glabrata to different immune challenges. In addition to sequences with relevant putative ID and Gene Ontology (GO) annotation, the array features non-immune factors and unknown B. glabrata ESTs for functional gene discovery. The transcription profiles of B. glabrata (3 biological replicates, each a pool of 5 snails) were recorded at 12 hours post wounding, exposure to Gram negative or Gram positive bacteria (Escherichia coli and Micrococcus luteus, respectively), or infection with compatible trematode parasites (S. mansoni or E. paraensei, 20 miracidia/snail), relative to controls, using universal reference RNA. The data were subjected to Significance Analysis for Microarrays (SAM), with a false positive rate (FPR) ≤10%. Wounding yielded a modest differential expression profile (27 up/21 down) with affected features mostly dissimilar from other treatments. Partially overlapping, yet distinct expression profiles were recorded from snails challenged with E. coli (83 up/20 down) or M. luteus (120 up/42 down), mostly showing up-regulation of defense and stressrelated features. Significantly altered expression of selected immune features indicates that B. glabrata detects and responds differently to compatible trematodes. Echinostoma paraensei infection was associated mostly with down regulation of many (immune-) transcripts (42 up/68 down), whereas S. mansoni exposure yielded a preponderance of up-regulated features (140 up/23 down), with only few known immune genes affected. These observations may reflect the divergent strategies developed by trematodes during their evolution as specialized pathogens of snails to negate host

The architectural features of 73 introns found in 36 genes of the fission yeast Schizosaccharomyces pombe have been compiled and tabulated. The introns from S. pombe can be grouped into two size classes. Intron features are discussed in comparison to intron features of Saccharomyces cerevisiae and other eukaryotes. The results indicate that S. pombe displays quite different architectural features than the budding yeast S. cerevisiae. However, particularly in the 3' region, S. pombe introns also appear to differ from mammalian introns.

Schistosomiasis is one of the foremost health problems in developing countries and has been estimated to account for the loss of up to 56 million annual disability-adjusted life years. Control of the disease relies almost exclusively on praziquantel (PZQ) but this drug does not kill juvenile worms during the early stages of infection or prevent post-treatment reinfection. As the use of PZQ continues to grow, there are fears that drug resistance may become problematic thus there is a need to develop a new generation of more broadly effective anti-schistosomal drugs, a task that will be made easier by having an understanding of why PZQ kills sexually mature worms but fails to kill juveniles. Here, we describe the exposure of mixed-sex juvenile and sexually mature male and female Schistosoma mansoni to 1 μg/mL PZQ in vitro and the use of microarrays to observe changes to the transcriptome associated with drug treatment. Although there was no significant difference in the total number of genes expressed by adult and juvenile schistosomes after treatment, juveniles differentially regulated a greater proportion of their genes. These included genes encoding multiple drug transporter as well as calcium regulatory, stress and apoptosis-related proteins. We propose that it is the greater transcriptomic flexibility of juvenile schistosomes that allows them to respond to and survive exposure to PZQ in vivo.

We have generated a bank of temperature-sensitive (ts) Schizosaccharomyces pombe mutant strains. About 150 of these mutants were transformed with a ura4 gene containing an artificial intron. We screened these ts mutants for mutants deficient in splicing of the ura4 intron. With this approach three mutants were isolated which have a general defect in the splicing process. Two of these mutants fall into the prp1 complementation group and one defines a new complementation group, prp4.