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In the present study, the ecotoxicity of silver nanoparticles (AgNPs) was investigated in Caenorhabditis elegans using survival, growth, and reproduction, as the ecotoxicological endpoints, as well as stress response gene expression. Whole genome microarray was used to screen global changes in C. elegans transcription profiles after AgNPs exposure, followed by quantitative analysis of selected genes. The integration of gene expression with organism and population level endpoints was investigated using C. elegans functional genomics tools, to test the ecotoxicological relevance of AgNPs-induced gene expression. AgNPs exerted considerable toxicity in C. elegans, most clearly as dramatically decreased reproduction potential. Increased expression of the superoxide dismutases-3 (sod-3) and abnormal dauer formation protein (daf-12) genes with 0.1 and 0.5 mg/L of AgNPs exposures occurred concurrently with significant decreases in reproduction ability. Overall results of functional genomic studies using mutant analyses suggested that the sod-3 and daf-12 gene expressions may have been related to the AgNPs-induced reproductive failure in C. elegans and that oxidative stress may have been an important mechanism in AgNPs toxicity.

To identify potential harmful effects of silver nanoparticles (AgNPs) on human health, a comprehensive toxicity assay was conducted on human Jurkat T cells, using oxidative stress-related endpoint. The effect of Ag ions was also investigated and compared with that of AgNPs, as it is anticipated that Ag ions will be released from AgNPs, which may be responsible for their toxicity. Cell viability tests indicated high sensitivity of Jurkat T cells when exposed to AgNPs compared to Ag ions; however, both AgNPs and Ag ions induce similar levels of cellular reactive oxygen species during the initial exposure period and; after 24 h, they were increased on exposure to AgNPs compared to Ag ions, which suggest that oxidative stress may be an indirect cause of the observed cytotoxicity of AgNPs. AgNPs exposure activates p38 mitogen-activated protein kinase through nuclear factor-E2-related factor-2 and nuclear factor-kappaB signaling pathways, subsequently inducing DNA damage, cell cycle arrest and apoptosis. Selective toxicity of AgNPs on Jurkat T cells suggests that rigorous toxicity evaluation should be conducted using various different cell types and biological systems prior to the widespread use of AgNPs.

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Rapid translation of genome sequences into meaningful biological information hinges on the integration of multiple experimental and informatics methods into a cohesive platform. Despite the explosion in the number of genome sequences available, such a platform does not exist for filamentous fungi. Here we present the development and application of a functional genomics and informatics platform for a model plant pathogenic fungus, Magnaporthe oryzae. In total, we produced 21,070 mutants through large-scale insertional mutagenesis using Agrobacterium tumefaciens-mediated transformation. We used a high-throughput phenotype screening pipeline to detect disruption of seven phenotypes encompassing the fungal life cycle and identified the mutated gene and the nature of mutation for each mutant. Comparative analysis of phenotypes and genotypes of the mutants uncovered 202 new pathogenicity loci. Our findings demonstrate the effectiveness of our platform and provide new insights on the molecular basis of fungal pathogenesis. Our approach promises comprehensive functional genomics in filamentous fungi and beyond.