Project description:Channel catfish (Ictalurus punctatus) and tra catfish (Pangasianodon hypophthalmus) both belong to the order Siluriformes. Channel catfish does not possess an air-breathing organ (ABO), and thus cannot breathe in the air, while tra catfish is a facultative air-breather and use the swim bladder as its air-breathing organ, which provides for aerial breathing in low oxygen conditions. Tra and channel catfish serve as a great comparative model for studying the transition of life from water to terrestrial living, as well as for understanding genes that are crucial for development of the swim bladder and the function of air-breathing in tra catfish. We selected seven developmental stages in tra catfish for RNA-Seq analysis based on their transition to a stage that could live at 0 ppm oxygen. More than 587 million sequencing clean reads were generated in tra catfish, and a total of 21, 448 unique genes were detected. A comparative genomic analysis was conducted between channel catfish and tra catfish. Gene expression analysis was performed for these tra catfish specific genes. Hypoxia challenge and microtomy experiments collectively suggested that there are critical timepoints for the development of the air-breathing function and swim bladder development stages in tra catfish. Key genes were identified to be the best candidates of genes related to the air-breathing ability in tra catfish. This study provides a large data resource for functional genomic studies in air-breathing function in tra catfish, and sheds light on the adaption of aquatic organisms to the terrestrial environment.
Project description:Healthy human and mouse colon epithelium is a major source of active thrombin, released in lumen. Using germ-free animals, we demonstrated that mucosal thrombin was directly regulated by the presence of commensal microbiota. Specific inhibition of lumenal thrombin activity caused macro-, microscopic damage and transcriptomic alterations of genes involved in host-microbiota interactions. Further, lumenal thrombin inhibition impaired the spatial segregation of microbiota biofilms, allowing bacteria to invade the mucus layer and to translocate across the epithelium. Thrombin proteolyzed the biofilm matrix of reconstituted mucosa-associated human microbiota. We demonstrated a previously unknown physiological role for epithelial thrombin that constrains biofilms at mucosal surfaces. We report that lung, bladder and skin epithelia also expressed thrombin, suggesting that this role may be applicable to other host-microbiome surfaces. Our discovery points route to new therapies targeting biofilms, important for a broad range of disorders, in the gut, and beyond.
Project description:The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome, biochemistry, morphology and physiology using morpholino (MO) knockdown. Knockdown of D1+D2 (D1D2MO) and knockdown of D3 (D3MO) both resulted in transcriptional regulation of metabolism and (muscle) development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidy. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidy is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in eye development and phototransduction was decreased in both knockdown conditions, suggesting that both may impair eye development and function. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct TH balance during vertebrate embryonic development. A-optimal design. Experimental design, D1D2MO vs SCMO and D3MO vs SCMO. Biological replicates: 4 SCMO, 4 D1D2MO, 4 D3MO
Project description:The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome, biochemistry, morphology and physiology using morpholino (MO) knockdown. Knockdown of D1+D2 (D1D2MO) and knockdown of D3 (D3MO) both resulted in transcriptional regulation of metabolism and (muscle) development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidy. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidy is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in eye development and phototransduction was decreased in both knockdown conditions, suggesting that both may impair eye development and function. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct TH balance during vertebrate embryonic development. A-optimal design. Experimental design, D1D2MO vs SCMO and D3MO vs SCMO. Biological replicates: 4 SCMO, 4 D1D2MO, 4 D3MO
Project description:We have previously demonstrated that the gut microbiota can play a role in the pathogenesis of conditions associated with exposure to environmental pollutants. It is well accepted that diets high in fermentable fibers such as inulin can beneficially modulate the gut microbiota and lessen the severity of pro-inflammatory diseases. Therefore, we aimed to test the hypothesis that hyperlipidemic mice fed a diet enriched with inulin would be protected from the pro-inflammatory toxic effects of PCB 126.
Project description:Japanese medaka (Oryzias latipes) embryos were exposed to two concentrations of the water accommodated fractions and chemically-enhanced water accommodated fractions of two types of diluted bitumen (dilbit). Chemical-dispersion did not significantly alter transcriptional responses to dilbit toxicity but may have acted through alternative mechanisms to give similar phenotypic responses, such as normal swim bladder development. This study identified novel biomarkers in fish with or without visual malformations exposed to dilbit that can be used to assess aquatic ecosystem health. Microarray analyses identified novel biomarkers and gene networks in dilbit-exposed malformed embryos that were not evident in unaffected dilbit-exposed fish or in controls.