Project description:The widespread use of silver nanoparticles (Ag NPs) has raised substantial health risks to environmental and human beings. Although various negative effects had been reported, little is known about the epigenetic toxicity induced by Ag+ and Ag NPs. This study characterized physiological and lncRNA profiles to explore the toxic effects and epigenetic mechanisms in Tetrahymena thermophila on exposure to Ag+ and three types of Ag NPs. We found that both of Ag+ and Ag NPs exhibited strong growth-inhibiting effects on T. thermophila. The toxicity was mainly caused by high levels of reactive oxygen species (ROS), which subsequently led to lipid peroxidation and mitochondrial dysfunction. As a defense mechanism against oxidative stress, the protist elicited an antioxidant response. Importantly, 1250 lncRNAs were differentially expressed under Ag+ or Ag NPs exposure relative to the non-exposure control, which were clustered into 15 expression modules in weighted gene co-expression network analysis. These gene modules exhibited toxicant-specific expression patterns, indicating that they play various regulatory roles, including cell growth inhibition, cell membrane cation channel activation, and oxidoreductase activity promotion. Taken together, this research illuminates how post-transcriptional mechanisms of a ciliated protozoa regulate responses to Ag+ and Ag NPs toxicities.
Project description:The toxicity of silver and zinc oxide nanoparticles is hypothesised to be mediated by dissolved metal ions and cerium dioxide nanoparticles (CeO2 NPs) are hypothesised to induce toxicity specifically by oxidative stress dependant on their surface redox state. To test these hypotheses, RNAseq was applied to characterise the molecular responses of cells to metal nanoparticle and metal ion exposures. The human epithelial lung carcinoma cell line A549 was exposed to different CeO2 NPs with different surface charges, micron-sized and nano-sized silver particles and silver ions, micron-sized and nano-sized zinc oxide particles and zinc ions, or control conditions, for 1 hour, 6 hours and 24 hours. Concentrations were the lower of either EC20 or 128 micrograms/mL. Transcriptional responses were characterised by RNAseq transcriptomics using an Illumina HiSeq2500 .
Project description:Five genome-wide microarrays were used to indentify gene expression in exposure to Tributyltin, Dichlorodiphenyltrichloroethane and 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin. The three environmental chemicals are persistent in environment and cause continuous toxical effects on human and aquatic life. Tetrahymena thermophila has the potential as a toxical model. The genome-wide microarray in Tetrahymena thermophila exposed to these toxicants was analyzed. First, genes differentially expressed under the treatment of each toxicant were identified and then their functions were categorized using GO enrichment analysis. The results may suggest that Tetrahymena thermophila is able to reflect different mechanism of different toxic-type toxicants which are similar to those in multicellular organisms. Regarding the complexity of TCDD effects, context likelihood of relatedness method (CLR) was applied to construct a TCDD-relevant network. General functions of the network are related to the epigenetic mechanism of TCDD. Based on the network analysis, a model of TCDD effect on T. thermophila was infered. Thus, Tetrahymena has the potential to be a good unicellular eukaryotic model for toxic mechanism research at genome level. Tetrahymena thermophila CU428 cells were cultured using 1XSPP, 30 degree, 100 rpm shaking, until 300,000 cells/ml. Cells at 300,000 cells/ml was incubated in SPP medium were treated. Two microarrays were used 4.02μl DMSO per ml SPP as the solvent and control; One microarray for 5 ppb TBT treatment 24 hours; One microarray for 1 ppb TCDD treatment 24 hours; One microarray for 4ppm DDT treatment for 24 hours.
Project description:We present a comprehensive transcriptome of ciliate T. thermophila using the Illumina RNA-seq platform. The data was generated from the six mRNA samples of growth, starvation and conjugation of Tetrahymena. Despite an AT rich genome, there are about 124.6 million reads mapped to T. thermophila genome. Using these mapped reads, we have significantly improved the previous genome annotation and investigated the gene expression. Besides, our result also provided a comprehensive understanding of the alternative splicing in T. thermophila, and suggested the existence of the regulated unproductive splicing and translation (RUST) in the single-celled eukaryote. RNA-seq for six samples of Tetrahymena growth, starvation and conjugation.
Project description:Five genome-wide microarrays were used to indentify gene expression in exposure to Tributyltin, Dichlorodiphenyltrichloroethane and 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin. The three environmental chemicals are persistent in environment and cause continuous toxical effects on human and aquatic life. Tetrahymena thermophila has the potential as a toxical model. The genome-wide microarray in Tetrahymena thermophila exposed to these toxicants was analyzed. First, genes differentially expressed under the treatment of each toxicant were identified and then their functions were categorized using GO enrichment analysis. The results may suggest that Tetrahymena thermophila is able to reflect different mechanism of different toxic-type toxicants which are similar to those in multicellular organisms. Regarding the complexity of TCDD effects, context likelihood of relatedness method (CLR) was applied to construct a TCDD-relevant network. General functions of the network are related to the epigenetic mechanism of TCDD. Based on the network analysis, a model of TCDD effect on T. thermophila was infered. Thus, Tetrahymena has the potential to be a good unicellular eukaryotic model for toxic mechanism research at genome level.
