Cryptococcal Cell Morphology Affects Host Cell Interactions and Pathogenicity

Cryptococcus neoformans is a common life-threatening human fungal pathogen. The size of cryptococcal cells is typically 5 to 10 µm. Cell enlargement was observed in vivo, producing cells up to 100 µm. These morphological changes in cell size affected pathogenicity via reducing phagocytosis by host mononuclear cells, increasing resistance to oxidative and nitrosative stress, and correlated with reduced penetration of the central nervous system. Cell enlargement was stimulated by coinfection with strains of opposite mating type, and ste3aΔ pheromone receptor mutant strains had reduced cell enlargement. Finally, analysis of DNA content in this novel cell type revealed that these enlarged cells were polyploid, uninucleate, and produced daughter cells in vivo. These results describe a novel mechanism by which C. neoformans evades host phagocytosis to allow survival of a subset of the population at early stages of infection. Thus, morphological changes play unique and specialized roles during infection

Positive Psychology Programs For Youth In Diverse Communities

Positive psychology interventions have shown great promise in promoting well-being. However, existing programs for both adults and youth have typically targeted predominantly affluent populations in high income communities and countries. Less is known about the relevance and benefits of positive psychology approaches with other populations. This chapter describes our team’s collective experience developing, implementing, and evaluating school-based positive psychology programs for youth (children and adolescents) in a variety of communities around the world, including communities in India, Kenya, and Canada. We discuss the relevance of positive psychology concepts, especially character strengths and resilience, and intervention approaches. We share lessons learned and recommendations for future work that can help to ensure positive psychology programs are cross-culturally relevant and responsive. Key among these are: (1) the importance of including local community members in each phase of program development, implementation, and evaluation, and (2) the necessity of flexibility when scaling programs to reach large populations