Project description:Diapause is a reversible developmental arrest faced by many organisms in harsh environments. Annual killifish present this mechanism in three possible stages of development. Killifish are freshwater teleosts from Africa and America that live in ephemeral ponds, which dry up in the dry season. The juvenile and adult populations die, and the embryos remain buried in the bottom mud until the next rainy season. Thus, species survival is entirely embryo-dependent, and they are perhaps the most remarkable extremophile organisms among vertebrates. The aim of the present study was to gather information about embryonic diapauses with the use of a “shotgun” proteomics approach in diapause III and prehatching Austrolebias charrua embryos. Our results provide insight into the molecular mechanisms of diapause III. We detected a diapause-dependent change in a large group of proteins involved in different functions, such as metabolic pathways and stress tolerance, as well as proteins related to DNA repair and epigenetic modifications. Furthermore, we observed a diapauseassociated switch in cytoskeletal proteins. This first glance into global protein expression differences between prehatching and diapause III could provide clues regarding the induction/maintenance of this developmental arrest in A. charrua embryos. There appears to be no single mechanism underlying diapause and the present data expand our knowledge of the molecular basis of diapause regulation. This information will be useful for future comparative approaches among different diapauses in annual killifish and/or other organisms that experience developmental arrest.
Project description:Embryos from 8 populations of killifish, four with evolved tolerances, were exposed to PCB-126. Approximately 5 replicate embryos per treatment/control were sequenced. Desensitization of aryl hydrocarbon receptor signaling to PCB-126 is found in all four populations with evolved pollution tolerance, and represents the strongest transcriptional difference between tolerant and sensitive populations.
Project description:The Atlantic killifish (Fundulus heteroclitus) is an ideal model species to study physiological and toxicological adaptations to stressors. Killifish inhabiting the PCB-contaminated Superfund site in New Bedford Harbor, MA (NBH) have evolved resistance to toxicity and activation of the aryl hydrocarbon receptor (AHR) signaling pathway after exposure to PCBs and other AHR agonists. Until recently, a lack of genomic information has limited efforts to understand the molecular mechanisms underlying environmental adaptation to stressors. The advent of high throughput sequencing has facilitated an unbiased assessment of coding as well as non-coding RNAs in any species of interest. Among non-coding RNAs, microRNAs (miRNAs) are important regulators of gene expression and play crucial roles in development and physiology. The objective of this study is to catalog the miRNAs in killifish and determine their expression patterns in the embryos from contaminated (NBH) and pristine (Scorton Creek, MA (SC)) sites. Embryos from NBH and SC were collected daily from 1 to 15 days post-fertilization and RNA from pooled samples from each site was sequenced using SOLiD sequencing. We obtained 7.5 and 11 million raw reads from pooled SC and NBH samples, respectively. Analysis of the sequencing data identified 216 conserved mature miRNA sequences that are expressed during development. Using the draft killifish genome, we retrieved the miRNA precursor sequences. Based on the capacity of these putative precursor sequences to form the characteristic hairpin loop (assessed using RNAfold), we identified 197 conserved miRNA sequences in the genome.
Project description:This SuperSeries is composed of the following subset Series: GSE22141: MicroRNA signature during the time course of regeneration of the human airway mucociliary epithelium GSE22142: Transcriptome analysis during the time course of regeneration of the human airway mucociliary epithelium GSE22143: Transcriptomic impact of microRNAs-449 or microRNAs-34 overexpression in proliferating human airway epithelial cells GSE22144: miRNAs high throughput sequencing profiling of regenerating human airway epithelial cells GSE22145: miRNAs high throughput sequencing profiling of basals cells and columnar cells GSE22146: microRNAs signatures of Xenopus laevis embryo epidermis at stage 11 (non ciliated) and 26 (ciliated) using high throughput sequencing Refer to individual Series
Project description:This study is focused on microRNAs in ovarian follicles and their predicted role in the pathways involved in oocyte growth and maturation. We determined the expression profiles of microRNAs in human oocytes and follicular fluid by high-throughput analysis, and identified the most significant Biological Processes and the pathways regulated by microRNA validated targets.
Project description:The European clam, Ruditapes decussatus (Linnaeus, 1758) is a bivalve mollusc of the family Veneridae native to the European Atlantic and Mediterranean coastal waters. Its production is exclusively based on natural recruitment, which is subject to high annual fluctuations due to adversely affected by pollution and other environmental factors. Microarray analyses have been performed in four gonadal maturation stages of two higly productive Portuguese wild populations (Ria Formosa in South and Ria de Aveiro in North) characterized by different responses to spawning induction.
