Project description:In zebrafish, parental exposure to ionizing radiation has been associated with effects in offspring, such as increased DNA damage and reactive oxygen species. Here, we assessed short (one month) and long term effects (one year) on gene expression in embryonic offspring (5.5 hours post fertilization) from zebrafish exposed during gametogenesis to gamma radiation (8.7 or 53 mGy/h for 27 days, total dose 5.2 or 31 Gy). One month after exposure, a global change in gene expression was observed in offspring from the 53 mGy/h group, followed by embryonic death at late gastrula, whereas offspring from the 8.7 mGy/h group was unaffected. One year after exposure, embryos from the 8.7 mGy/h group exhibited 2455(61.8% downregulated) differentially expressed genes. Overlaps in differentially expressed genes and enriched biological pathways were evident between the 53 mGy/h group one month and 8.7 mGy/h one year after exposure, which could be linked to effects in adults and offspring, such as DNA damage and lipid peroxidation. Interestingly, pathways between the two groups were oppositely regulated. Our results indicate latent effects following ionizing radiation exposure in parents that can be transmitted to offspring and warrants monitoring effects over subsequent generations.
Project description:<p>Organic carbon in seawater plays a significant role in the global carbon cycle. The concentration and composition of dissolved organic carbon, operationally defined in this project as organic carbon that passes through a 0.2 µm filter, reflect the actions of the biological community and chemical reactions that occur in seawater. Here, we repeatedly sampled the oligotrophic northwest Sargasso Sea in the vicinity of the Bermuda Atlantic Time-Series Study site (BATS) to quantitatively follow select known compounds within the pool of dissolved organic matter in the upper 1000 meters of the water column over a four-year period. Metabolite concentrations revealed patterns with depth and time with most metabolites showing surface enrichment and lower concentrations with depth. Select metabolites had a pattern of increased and decreased concentrations throughout the year, which was observed in each of the years sampled. Vitamins, including pantothenic acid, biotin, and riboflavin, presented annual increases in the winter period when mixed layer depths are deepest. Light-sensitive riboflavin also showed significant decreases during daylight hours under diel sampling. The metabolites examined in this study are all components of central carbon metabolism. By examining these metabolites at finer resolution and in a relatively long time series, we have clues on microbial actions in marine systems, data which are fundamental to understanding the chemical response of marine systems to future changes in climate.</p>
Project description:Despite intensive toxicological studies of carbon nanotubes (CNTs) over the last two decades, only a few studies have demonstrated their pulmonary carcinogenicities in chronic animal experiments, and the underlying molecular mechanisms are still unclear. To obtain molecular insights into CNT-induced lung carcinogenicity, we performed a transcriptomic analysis using a set of lung tissues collected from rats in a 2-year study, in which lung tumors were induced by repeated intratracheal instillations of a multiwalled carbon nanotube, MWNT-7. The RNA-seq-based transcriptome identified a large number of significantly differentially expressed genes at Year 0.5, Year 1, and Year 2. Ingenuity Pathway Analysis revealed that macrophage-elicited signaling pathways such as phagocytosis, acute phase response, and Toll-like receptor signaling were activated throughout the experimental period. At Year 2, cancer-related pathways including ERBB signaling and some axonal guidance signaling pathways such as EphB4 signaling were perturbed. qRT-PCR and immunohistochemistry indicated that several key molecules such as Osteopontin/Spp1, Hmox1, Mmp12, and ERBB2 were markedly altered and/or localized in the preneoplastic lesions, suggesting their participation in the induction of lung cancer. Our findings support a scenario of inflammation-induced carcinogenesis and contribute to a better understanding of the molecular mechanism of MWCNT carcinogenicity.