Gene Expression Patterns in Larval Schistosoma mansoni Associated with Infection of the Mammalian Host

The schistosome cercaria develops from undifferentiated germ balls within the daughter sporocyst located in the hepatopancreas of its snail intermediate host. This is where the proteins it uses to infect humans are synthesised. After a brief free life in fresh water, if the cercaria locates a host, it infects by direct penetration through the skin. It then transforms into the schistosomulum stage, adapted for life in human tissues. We have designed a large scale array comprising probes representing all known schistosome genes and used it in hybridisation experiments to establish which genes are turned on or off in the parasite during these stages in its life cycle. Genes encoding proteins involved in cell division were prominent in the germ ball along with those for proteases and potential immunomodulators, deployed during skin penetration. The non-feeding cercaria was the least active at synthesising proteins. Conversion to the schistosomulum was accompanied by transcription of genes involved in body remodeling, including production of a new outer surface, and gut activation long before ingestion of red blood cells begins. Our data help us to understand better the proteins deployed to achieve infection, and subsequent adaptations necessary for establishment of the parasite in the human host

Positive Behavior Interventions: the Issue of Sustainability of Positive Effects

During the last decade, positive behavior interventions have resulted in improvement of school behavior and academic gains in a range of school settings worldwide. Recent studies identify sustainability of current positive behavior intervention programs as a major concern. The purpose of this article is to identify future direction for effective implementation of positive behavior interventions based on a comprehensive review of the current status of positive behavior interventions in terms of sustainability. The review will also examine implementation fidelity, as a factor that impacts upon sustainability. Literature reviewed in this study demonstrates that administrator support and professional development were the most frequently cited influential factors in previous research on sustainability of positive behavior interventions. In particular, the review highlights the significance of implementation fidelity at the classroom level for sustaining positive outcomes of positive behavior interventions over time. It is argued that in order to sustain positive effects of positive behavior intervention, future implementation efforts need to emphasize administrator support for the school team, ongoing high-quality professional development, and technical assistance. Moreover, a focus on coaching classroom-level implementation fidelity is of significant importance, as is the development and validation of evaluation tools for sustainability based on large-scale longitudinal international studies and more in-depth qualitative investigations