Project description:Background: Cnidarian – dinoflagellate intracellular symbioses are one of the most important mutualisms in the marine environment. They form the trophic and structural foundation of coral reef ecosystems, and have played a key role in the evolutionary radiation and biodiversity of cnidarian species. Despite the prevalence of these symbioses, we still know very little about the molecular modulators that initiate, regulate, and maintain the interaction between these two different biological entities. In this study, we conducted a comparative host anemone transcriptome analysis using a cDNA microarray platform to identify genes involved in cnidarian – algal symbiosis. Results: We detected statistically significant differences in host gene expression profiles between sea anemones (Anthopleura elegantissima) in a symbiotic and non-symbiotic state. The group of genes, whose expression is altered, is diverse, suggesting that the molecular regulation of the symbiosis is governed by changes in multiple cellular processes. In the context of cnidarian – dinoflagellate symbioses, we discuss pivotal host gene expression changes involved in lipid metabolism, cell adhesion, cell proliferation, apoptosis, and oxidative stress. Conclusion: Our data do not support the existence of symbiosis-specific genes involved in controlling and regulating the symbiosis. Instead, it appears that the symbiosis is maintained by altering expression of existing genes involved in vital cellular processes. Specifically, the finding of key genes involved in cell cycle progression and apoptosis have led us to hypothesize that a suppression of apoptosis, together with a deregulation of the host cell cycle, create a platform that might be necessary for symbiont and/or symbiont-containing host cell survival. This first comprehensive molecular examination of the cnidarian – dinoflagellate associations provides critical insight into the maintenance and regulation of the symbiosis. Keywords: comparative genomic hybridization
Project description:We report the transcriptomic analyses of a tropical coralliomrpharian, Ricordea yuma, following the establishment of symbiosis with either native symbiont or non-native symbiont. We examined the expression profiles, and results showed distinct metabolic consequences for the cnidarian host when they host different symbionts.
Project description:We performed single-cell transcriptome analysis (using MARS-seq) in the cnidarian Nematostella vectensis. Additionally we performed bulk ATAC-seq experiments on wild-type specimens, as well as ELAV::mOrange reporter transgenic lines (separating ELAV+ and ELAV- cell populations, representing neurons and non-neurons, respectively).
Project description:We utilized the Nematostella vectensis to quantify gene expression differences and loss during light:dark cycling and immediately after light cue removal through comparisons of 136 transcriptomes Organismal responses to light:dark cycles can result from two general processes: (i) direct response to light or (ii) a free-running rhythm (i.e., a circadian clock). Previous research in cnidarians has shown that candidate circadian clock genes have rhythmic expression in the presence of diel lighting, but these oscillations appear to be lost quickly after removal of the light cue. Here, we measure whole-organism gene expression changes in 136 transcriptomes of the sea anemone Nematostella vectensis, entrained to a light:dark environment and immediately following light cue removal to distinguish two broadly defined responses in cnidarians: light entrainment and circadian regulation. Direct light exposure resulted in significant differences in expression for hundreds of genes, including more than 200 genes with rhythmic, 24-hour periodicity. Removal of the lighting cue resulted in the loss of significant expression for 80% of these genes after one day, including most of the hypothesized cnidarian circadian genes. Further, 70% of these candidate genes were phase shifted. Most surprisingly, thousands of genes, some of which are involved in oxidative stress, DNA damage response, and chromatin modification, had significant differences in expression in the 24 hours following light removal, suggesting that loss of the entraining cue may induce a cellular stress response. Together, our findings suggest that a majority of genes with significant differences in expression for anemones cultured under diel lighting are largely driven by the primary photoresponse rather than a circadian clock when measured at the whole animal level. These results provide context for the evolution of cnidarian circadian biology and help to disassociate two commonly confounded factors driving oscillating phenotypes.
Project description:Protein reference databases are a critical part of producing efficient proteomic analyses. However, the method for constructing clean, efficient, and comprehensive protein reference databases is lacking. Existing methods either do not have contamination control procedures, or these methods rely on a three-frame and/or six-frame translation that sharply increases the search space and harms MS results. Herein we propose a framework for constructing a customized comprehensive proteomic reference database (CCPRD) from draft genomes and deep sequencing transcriptomes. Its effectiveness is demonstrated by incorporating the proteomes of nematocysts from endoparasitic cnidarian: myxozoans. By applying customized contamination removal procedures, contaminations in omic data were successfully identified and removed. This is an effective method that does not result in over-decontamination. This can be shown by comparing the CCPRD MS results with an artificially-contaminated database and another database with removed contaminations in genomes and transcriptomes added back. CCPRD outperformed traditional frame-based methods by identifying 35.2%-50.7% more peptides and 35.8%-43.8% more proteins, with a maximum 84.6% in size reduction. A BUSCO analysis showed that the CCPRD maintained a relatively high level of completeness compared to traditional methods. These results confirm the superiority of the CCPRD over existing methods in peptide and protein identification numbers, database size, and completeness. By providing a general framework for generating the reference database, the CCPRD, which does not need a high-quality genome, can potentially be applied to any organisms and significantly contribute to proteomic research.
Project description:We introduce FACIL (http://www.cmbi.ru.nl/FACIL), a fast, reliable tool to evaluate nucleic acid sequences for non-standard codes that detects alternative genetic codes even in species distantly related to known organisms. Results are visualized in a Genetic Code Logo. To illustrate the use of our method, we analysed several contigs derived from the mitochondrial genome of the foraminifer Globobulimina pseudospinescens. These are particularly challenging data, as the genome is highly fragmented and incomplete. Approximately 10,000 single-cell Globobulimina pseudospinescens organisms were isolated by hand from Gullmar Fjord Sweden sediment. After washing, total DNA was extracted and sequenced by Illumina sequencing. The reads were assembled using Edena. To illustrate the use of our method, we analysed several contigs derived from the mitochondrial genome of the foraminifer Globobulimina pseudospinescens, an organism without any sequenced relatives in the databases. These are particularly challenging data, as the genome is highly fragmented and incomplete. DNA isolated from approximately 10,000 single-cell Globobulimina pseudospinescens organisms
Project description:The aim of this study was to illustrate the breadth of venom evolution in cnidarians and to determine if venom toxins have been co-opted and modified for parasitic lifestyles. Samples representing cnidarian taxa with entirely parasitic life cycles (myxozoans), entirely free-living life cycles, and a life cycle containing both parasitic and free-living stages (P. hydriforme). were obtained for analysis, which comprised of comparative transcriptomics, proteomics and the use of a custom bioinformatics pipeline developed to screen and identify toxins within these datasets.
Project description:Using forward transcriptomics, we show that beta-catenin/Tcf signaling and BMP2/4 signaling provide differential inputs into the cnidarian endomesodermal gene regulatory network (GRN) at the onset of gastrulation (24 h postfertilization) in N. vectensis. Surprisingly, beta-catenin/Tcf signaling and BMP2/4 signaling regulate a subset of common downstream target genes in the GRN in opposite ways, leading to the spatial and temporal differentiation of fields of cells in the developing embryo. Thus, we show that regulatory interactions between beta-catenin/Tcf signaling and BMP2/4 signaling are required for the specification and determination of different embryonic regions and the patterning of the oral?aboral axis in Nematostella.
Project description:We introduce FACIL (http://www.cmbi.ru.nl/FACIL), a fast, reliable tool to evaluate nucleic acid sequences for non-standard codes that detects alternative genetic codes even in species distantly related to known organisms. Results are visualized in a Genetic Code Logo. To illustrate the use of our method, we analysed several contigs derived from the mitochondrial genome of the foraminifer Globobulimina pseudospinescens. These are particularly challenging data, as the genome is highly fragmented and incomplete. Approximately 10,000 single-cell Globobulimina pseudospinescens organisms were isolated by hand from Gullmar Fjord Sweden sediment. After washing, total DNA was extracted and sequenced by Illumina sequencing. The reads were assembled using Edena. To illustrate the use of our method, we analysed several contigs derived from the mitochondrial genome of the foraminifer Globobulimina pseudospinescens, an organism without any sequenced relatives in the databases. These are particularly challenging data, as the genome is highly fragmented and incomplete.