Project description:This SuperSeries is composed of the following subset Series: GSE29854: Daphnia magna exposed to narcotics and polar narcotics - aniline GSE29856: Daphnia magna exposed to narcotics and polar narcotics - 4-chloroaniline GSE29857: Daphnia magna exposed to narcotics and polar narcotics - 3,5-dichloroaniline GSE29858: Daphnia magna exposed to narcotics and polar narcotics - 2,3,4-trichloroaniline GSE29862: Daphnia magna exposed to narcotics and polar narcotics - ethanol GSE29864: Daphnia magna exposed to narcotics and polar narcotics - isopropanol GSE29867: Daphnia magna exposed to narcotics and polar narcotics - methanol Refer to individual Series
Project description:Daphnia (Daphnia pulex) is a small planktonic crustacean and a key constituent of aquatic ecosystems. It is commonly used as a model organism for studying environmental toxic challenges. In the past decade, a Daphnia genomic information and proteomic dataset has been developed. This dataset has expanded the opportunity to relate toxicological effects with “Daphnia proteomics” as it integrates proteomic knowledge in Daphnia, those approach will provide greater insights for toxicological research. In order to exploit Daphnia for ecotoxicological research, information on the post-translational modification (PTM) of proteins is necessary as this is a critical regulator of biological processes. Acetylation of lysine (Kac) is a reversible and highly regulated PTM that is associated with diverse biological functions. However, a comprehensive description of Kac in Daphnia is not yet available. Here, to understand the cellular distribution of lysine acetylation in Daphnia, we identified 98 acetylation sites in 65 proteins by immunoprecipitation using an anti-acetyllysine antibody and an liquid chromatography system supported by mass spectroscopy. We identified 28 acetylated sites connected with metabolic proteins and 6 acetylated enzymes associated with the TCA cycle in Daphnia. From GO and KEGG enrichment analyses, we showed that Kac in D. pulex is highly enriched in proteins associated with metabolic processes. Our data provide the first global analysis of lysine acetylation in D. pulex. The expanded proteomic dataset will be an important resource for the functional analysis of Kac in D. pulex and it will be nice to have a first step done using a promising future model organism.
Project description:Determine gene expression in daphnia exposed to biotic and abiotic stressors. Identify in Daphnia pulex unique gene regulatory patterns involved in the regulation of limited phosphorous. One-condition experiment: Exposed Daphnia pulex for 5 days to phosphorous-limited algae. Biological replicates: 4 exposures, 4 nonexposed controls, grown and harvested in groups of 20 daphnia. One replicate per array.
Project description:Determine gene expression in daphnia exposed to biotic and abiotic stressors. Identify in Daphnia pulex unique gene regulatory patterns involved in the regulation of limited phosphorous.
Project description:Background/Objectives: The waterflea Daphnia is an interesting candidate for biore- generative life support systems (BLSS). These animals are particularly promising be- cause of their central role in the limnic food web and its mode of reproduction. How- ever, the response of Daphnia to altered gravity conditions has to be investigated, especially on the molecular level, to evaluate the suitability of Daphnia for BLSS in space. Methods: In this study, we applied a proteomic approach to identify key proteins and pathways involved in the response of Daphnia to simulated microgravity gener- ated by a 2D-clinostat. We analysed 5 biological replicates using 2D-DIGE proteomic analysis. Results: We identified 109 protein spots differing in intensity (p < 0.05). Substan- tial fractions of these proteins are involved in actin microfilament organisation, in- dicating the disruption of cytoskeletal structures during clinorotation. Furthermore, proteins involved in protein folding were identified, suggesting altered gravity in- duced break-down of protein structures in general. In addition, simulated micro- gravity increased the abundance of energy metabolism related proteins, indicating an enhanced energy demand of Daphnia. Conclusion: The affected biological processes were also described in other studies using different organisms and systems either aiming to simulate microgravity con- ditions or providing real microgravity conditions. Moreover, most of the Daphnia protein sequences are well conserved throughout taxa, indicating that the response to altered gravity conditions in Daphnia follows a general concept.
Project description:The cuticles of arthropods, including aquatic crustaceans like Daphnia, provide an interface between the organism and its environment. Thus, the cuticle’s structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the molted cuticle of Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology, anddetected 278 high confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin modifying enzymes as most abundant protein groups in the cuticle proteome.Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle . Finally, cuticle protein genes were clustered as tandem gene arrays in the Daphnia genome, indicating their importance for adaptation to environmental change. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing investigations on diverse topics such as the genetic basis of interactions with predators and parasites.
Project description:The cuticles of arthropods, including aquatic crustaceans like Daphnia, provide an interface between the organism and its environment. Thus, the cuticle’s structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the molted cuticle of Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology, anddetected 278 high confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin modifying enzymes as most abundant protein groups in the cuticle proteome.Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle . Finally, cuticle protein genes were clustered as tandem gene arrays in the Daphnia genome, indicating their importance for adaptation to environmental change. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing investigations on diverse topics such as the genetic basis of interactions with predators and parasites.
Project description:Comparison of female and male Daphnia magna gene expression with age. The sexes in Daphnia magna are genetically identical. The aim of this study was to identify possible differences in gene expression between genders with age.
Project description:Background Daphnia species reproduce by cyclic parthenogenesis involving both sexual and asexual reproduction. The sex of the offspring is environmentally determined and mediated via endocrine signalling by the mother. Interestingly, male and female Daphnia can be genetically identical, yet display large differences in behaviour, morphology, lifespan and metabolic activity. Our goal was to integrate multiple omics datasets, including gene expression, splicing, histone modification and DNA methylation data generated from genetically identical female and male Daphnia pulex under controlled laboratory settings with the aim of achieving a better understanding of the underlying epigenetic factors that may contribute to the phenotypic differences observed between the two genders. Results In this study we demonstrate that gene expression level is positively correlated with increased DNA methylation, and histone H3 trimethylation at lysine 4 (H3K4me3) at predicted promoter regions. Conversely, elevated histone H3 trimethylation at lysine 27 (H3K27me3), distributed across the entire transcript length, is negatively correlated with gene expression level. Interestingly, male Daphnia are dominated with epigenetic modifications that globally promote elevated gene expression, while female Daphnia are dominated with epigenetic modifications that reduce gene expression globally. For examples, CpG methylation (positively correlated with gene expression level) is significantly higher in almost all differentially methylated sites in male compared to female Daphnia. Furthermore, H3K4me3 modifications are higher in male compared to female Daphnia in more than 3/4 of the differentially regulated promoters. On the other hand, H3K27me3 is higher in female compared to male Daphnia in more than 5/6 of differentially modified sites. However, both sexes demonstrate roughly equal number of genes that are up-regulated in one gender compared to the other sex. Since, gene expression analyses typically assume that most genes are expressed at equal level among samples and different conditions, and thus cannot detect global changes affecting most genes. Conclusions The epigenetic differences between male and female in Daphnia pulex are vast and dominated by changes that promote elevated gene expression in male Daphnia. Furthermore, the differences observed in both gene expression changes and epigenetic modifications between the genders relate to pathways that are physiologically relevant to the observed phenotypic differences.