Project description:Diazotrophs provide the main source of reactive nitrogen to the ocean, sustaining primary productivity and CO2 uptake. Climate change is raising temperatures, decreasing pH and reducing nutrient availability. How microbes respond to these changes is largely unexplained. Similarly, the role of DOM in the growth and survival of certain diazotrophic organisms is poorly understood. Moreover, growing evidence indicates some diazotrophs are capable of utilizing distinct DOM compounds via osmotrophy providing them with additional metabolic plasticity and ecological advantages compared to other non-diazotrophic microbes. We aimed to understand how osmotrophy could modify carbon uptake and alleviate energy stress in diazotrophs under ongoing climate change perturbations. We hypothesized that Crocosphaera preferentially uses DOM when labile as a carbon source in present pH conditions, as compared to future more acidic scenarios with higher access to inorganic carbon. Alternatively, the lower pH may cause Crocosphaera to be energy limited when trying to maintain intracellular homeostasis which would favour DOM uptake as an extra source of energy.
Project description:Hirschsprung’s disease (HSCR) is a congenital disease which is characterized by the reduction or absence of neurons and glial cells in the enteric nervous system (ENS). Failure of neural crest cells (NCCs) to colonize the gut during the embryonic development has been considered as one of the possible causes of the disease. In this study, the migration and gene expression of sacral NCCs from the spontaneous mouse mutant Dominant megacolon (Dom) which is a HSCR animal model expressing a mutated transcription factor Sox10, were analyzed in order to identify candidate genes which may possibly affect the NCC migration in the mutant.
Project description:The transcriptome analysis by the human DNA microarray was applied to evaluate the impacts of whole wastewater effluents from the membrane bioreactors (MBRs) and the activated sludge process (AS), on the biological processes of human hepatoma HepG2 cells. The three conventional bioassays (i.e., cytotoxicity tests and bioluminescence inhibition test) and chemical analysis of the domestic effluent standards were conducted in parallel since they are well-established methods with previous applications to wastewater. A significant variation of effluent quality was sdemonstrated among the tested effluents despite that all effluents met the 40 national effluent standards. The three conventional bioassays supported the result of the transcriptome analysis, indicating the comparable or even higher sensitivity of the new assay. The most superior effluent quality was found in the MBR operated at a relatively long sludge retention time (i.e., 40 days) and small membrane pore size (i.e., 0.03 μm). In addition, functional analysis of the differentially expressed genes revealed that the effluents made various impacts on the cellular functions, suggesting the transcriptome analysis by DNA microarray as more comprehensive, rapid and sensitive tool to detect multiple impacts of the whole effluents. Moreover, the potential genetic markers were proposed to quantitatively evaluate the treatability of the wastewater effluents.
Project description:The transcriptome analysis by the human DNA microarray was applied to evaluate the impacts of whole wastewater effluents from the membrane bioreactors (MBRs) and the activated sludge process (AS), on the biological processes of human hepatoma HepG2 cells. The three conventional bioassays (i.e., cytotoxicity tests and bioluminescence inhibition test) and chemical analysis of the domestic effluent standards were conducted in parallel since they are well-established methods with previous applications to wastewater. A significant variation of effluent quality was sdemonstrated among the tested effluents despite that all effluents met the 40 national effluent standards. The three conventional bioassays supported the result of the transcriptome analysis, indicating the comparable or even higher sensitivity of the new assay. The most superior effluent quality was found in the MBR operated at a relatively long sludge retention time (i.e., 40 days) and small membrane pore size (i.e., 0.03 M-NM-<m). In addition, functional analysis of the differentially expressed genes revealed that the effluents made various impacts on the cellular functions, suggesting the transcriptome analysis by DNA microarray as more comprehensive, rapid and sensitive tool to detect multiple impacts of the whole effluents. Moreover, the potential genetic markers were proposed to quantitatively evaluate the treatability of the wastewater effluents. In this study, we examined the gene expression alteration in human hepatoma cell line, HepG2 exposed to the raw wastewater, effluents from three types of membrane bioreactors (MBRs), and the activated sludge process. Wastewater DNA microarray with 8795 human genes. MQ water was used as control. For duplicate, two dishes were prepared for each sample and individually treated in parallel.