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• W2767901190 abstract "Author(s): Scanlan, Leona Dance | Advisor(s): Vulpe, Christopher D | Abstract: Chemical contaminants are being detected with increasing frequency in the environment, both as a result of better analytical monitoring techniques and from increasing concentrations. It is important to understand if un-monitored contaminant chemicals can affect or cause toxicity in organisms of ecological importance or affect ecological health. Acute toxicity testing is a usual first step to determine effects on model organisms. In this work, the nominal acute LC50 (concentration that kills fifty percent of animals tested) was established for chemicals from two classes of emerging contaminants, silver nanowires and chemical flame-retardants, on freshwater crustacean, Daphnia magna. Gene expression studies were then done with microarray technology at sub-acute 1/10 nominal LC50 concentrations to determine genes differentially expressed in exposed animals as compared to control. Results were computationally analyzed with KEGG gene ontology pathway analysis to determine biological pathways affected, and with HOPACH clustering to determine similarities between different gene expression profiles. In each class of contaminant, each different exposure elicited a largely unique gene expression profile. Further studies on characterization of the nanowires in Daphnia growth media and on nanowire uptake were conducted, and high-throughput, short-read sequencing was done on Daphnia magna RNA samples. A de novo transcriptome was assembled and used for differential gene expression analysis of sequenced RNA from control and silver nanowire-exposed daphnids. The silver nanowires investigated in this study were long and short polyvinylpyrrolidone-coated silver nanowires (PVP AgNW) and long and short silica-coated silver nanowires (SiO2 AgNW). Ionic silver (Ag+) was also tested. Silver nanowires were not as toxic as ionic silver, and toxicity varied as a function of size and of coating and in different Daphnia growth media. Toxicity could not be attributed to the concentration of dissolved silver in media, but might be caused by internal silver dosing and by a nanowire-specific effect, perhaps related to nanowire shape. The short SiO2 coated AgNWs caused the most similar response to Ag+, and were also the most toxic of the nanowires. The long PVP AgNWs were the least toxic material under most conditions, and caused the most unique gene expression profile. This is the first study to show what appears to be uptake and in vivo modification of nanowires into an animal and the first to show toxic effects of a silver nanomaterial both caused by and independent of silver. De novo assembly of short-read sequencing data resulted in a robust Daphnia magna transcriptome. Over 101,000 unique transcripts were identified, which illustrated the power of new sequencing technologies and computation algorithms to identify alternate splicing of RNA transcripts. The generated transcriptome was used as a scaffold on which short-read sequencing data were aligned to analyze differential gene expression in control versus AgNW-exposed animals. Preliminary results showed that gene expression analysis with sequencing data resulted in different numbers of differentially expressed genes than were determined with microarray techniques. A combination of four align-and-count methods were subsequently used, which all resulted in different sets of differentially expressed genes. Further work on confirming which method is best for this dataset will need to be done before the sequencing results can be further compared to microarray results. To date, it is unclear whether gene expression studies using sequencing data are more robust or informative than studies with microarray data. However, the assembled transcriptome represents a significant Daphnia magna genomic contribution. The chemical flame-retardant nominal LC50 values ranged from 58 μg/L (pentaBDE) to 3.96 mg/L (octaBDE). These chemicals are not very soluble in water, so the LC50 values only represent the amount of chemical added to the exposure system, not the amount of chemical dissolved in water or the amount of chemical available to the animals. These nominal LC50 values likely underestimate toxicity of FRs to Daphnia magna. Chemical flame-retardants tested were Firemaster® 550 (FM550), Firemaster® BZ54 (BZ54), pentabrominated diphenyl ether (pentaBDE), octabrominated diphenyl ether (octaBDE), triphenyl phosphate (TPP), tetrabromobenzoate (TBPH). The un-brominated analog to TBPH, phthalate di(2-ethylhexyl) phthalate (DEHP), was also tested. Gene expression profiles had little similarity between chemicals, indicating potentially unique biological effects instead of general toxicity, such as by narcosis. Additional lipidomic and metabolomic studies with FM550 and pentaBDE at 1/10 LC50 showed distinct differences between effects of the two compounds. Genomic results indicate that FM550 exposure may affect transcription and translation of mRNA in Daphnia magna, but further studies are warranted to determine exact mode of toxicity. Both chemical flame-retardants and silver nanowires are highly toxic to Daphnia magna and cause unique molecular responses. However, exposure concentrations used in this study are typically higher than concentrations detected in environmental samples. Further studies are needed at lower concentrations to confirm the lower limits of effect, and to further investigate specific modes of toxicity. Distinct biological processes were affected by exposure to each chemical and by exposure to different concentrations of one chemical, FM550. This work was limited by lack of annotation of the Daphnia genome and by limited characterization of the Daphnia proteome. Molecular studies in Daphnia were limited, as Daphnia cell lines do not exist. This work contributes, however, to basic knowledge about acute toxicity and molecular effects of environmental contaminants." @default.
• W2767901190 created "2017-11-17" @default.
• W2767901190 creator A5007615934 @default.
• W2767901190 date "2012-01-01" @default.
• W2767901190 modified "2023-09-27" @default.
• W2767901190 title "The Toxicity of Chemical Flame-retardants and Silver Nanowires: An omics approach" @default.
• W2767901190 cites W1457590047 @default.
• W2767901190 cites W1717443758 @default.
• W2767901190 cites W184238969 @default.
• W2767901190 cites W1964895626 @default.
• W2767901190 cites W1966173257 @default.
• W2767901190 cites W1966584010 @default.
• W2767901190 cites W1969149930 @default.
• W2767901190 cites W1969501587 @default.
• W2767901190 cites W1970804271 @default.
• W2767901190 cites W1971425761 @default.
• W2767901190 cites W1973492979 @default.
• W2767901190 cites W1973849536 @default.
• W2767901190 cites W1985336009 @default.
• W2767901190 cites W1985791906 @default.
• W2767901190 cites W1986684489 @default.
• W2767901190 cites W1986730836 @default.
• W2767901190 cites W1989614455 @default.
• W2767901190 cites W1989696712 @default.
• W2767901190 cites W1989984587 @default.
• W2767901190 cites W1992451508 @default.
• W2767901190 cites W1993246714 @default.
• W2767901190 cites W2002473465 @default.
• W2767901190 cites W2009139504 @default.
• W2767901190 cites W2009460761 @default.
• W2767901190 cites W2010743184 @default.
• W2767901190 cites W2011970591 @default.
• W2767901190 cites W2017300013 @default.
• W2767901190 cites W2017703249 @default.
• W2767901190 cites W2017757998 @default.
• W2767901190 cites W2020741069 @default.
• W2767901190 cites W2020761921 @default.
• W2767901190 cites W2022221911 @default.
• W2767901190 cites W2025287221 @default.
• W2767901190 cites W2025586279 @default.
• W2767901190 cites W2025836627 @default.
• W2767901190 cites W2029348015 @default.
• W2767901190 cites W2031107569 @default.
• W2767901190 cites W2031139648 @default.
• W2767901190 cites W2034900106 @default.
• W2767901190 cites W2035038927 @default.
• W2767901190 cites W2035141835 @default.
• W2767901190 cites W2036294480 @default.
• W2767901190 cites W2040135323 @default.
• W2767901190 cites W2049971492 @default.
• W2767901190 cites W2052656160 @default.
• W2767901190 cites W2052827499 @default.
• W2767901190 cites W2054062945 @default.
• W2767901190 cites W2054297278 @default.
• W2767901190 cites W2058268533 @default.
• W2767901190 cites W2060471092 @default.
• W2767901190 cites W2061930666 @default.
• W2767901190 cites W2062144566 @default.
• W2767901190 cites W2062837315 @default.
• W2767901190 cites W2062896692 @default.
• W2767901190 cites W2062966370 @default.
• W2767901190 cites W2067127132 @default.
• W2767901190 cites W2067914062 @default.
• W2767901190 cites W2071637378 @default.
• W2767901190 cites W2073927364 @default.
• W2767901190 cites W2075561302 @default.
• W2767901190 cites W2075991090 @default.
• W2767901190 cites W2078034860 @default.
• W2767901190 cites W2079379437 @default.
• W2767901190 cites W2079489819 @default.
• W2767901190 cites W2080726206 @default.
• W2767901190 cites W2085155194 @default.
• W2767901190 cites W2085206997 @default.
• W2767901190 cites W2085350830 @default.
• W2767901190 cites W2085479163 @default.
• W2767901190 cites W2088031723 @default.
• W2767901190 cites W2089608147 @default.
• W2767901190 cites W2092645143 @default.
• W2767901190 cites W2094343211 @default.
• W2767901190 cites W2094577244 @default.
• W2767901190 cites W2100668965 @default.
• W2767901190 cites W2103915778 @default.
• W2767901190 cites W2109636763 @default.
• W2767901190 cites W2110611073 @default.
• W2767901190 cites W2112165279 @default.
• W2767901190 cites W2114090345 @default.
• W2767901190 cites W2114104545 @default.
• W2767901190 cites W2114197359 @default.
• W2767901190 cites W2114438914 @default.
• W2767901190 cites W2117822166 @default.
• W2767901190 cites W2123424849 @default.
• W2767901190 cites W2125454196 @default.
• W2767901190 cites W2128174440 @default.
• W2767901190 cites W2128222086 @default.
• W2767901190 cites W2132854878 @default.
• W2767901190 cites W2132872911 @default.
• W2767901190 cites W2133465414 @default.
• W2767901190 cites W2142900854 @default.
• W2767901190 cites W2148461214 @default.
• W2767901190 cites W2152239989 @default.

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