Project description:This SuperSeries is composed of the following subset Series: GSE27022: Microarray studies of darkness stress and bleaching in the Caribbean coral Acropora palmata GSE27024: Microarray studies of darkness stress and bleaching in the Caribbean coral Montastraea faveolata Refer to individual Series
Project description:Disturbance events are an important component of the ecology of coral reefs and increasingly frequent disturbances coupled with a lack of population resilience may contribute to changes in the structure of coral reef communities. The harvest of the Caribbean octocoral Antillogorgia elisabethae provides an opportunity to explore the relationship between adult abundance and recruitment and the manner in which recruitment contributes to the resilience of local populations. Recruitment of A. elisabethae was monitored in 20, 1-m(2) quadrats at 8 sites along the southern edge of the Little Bahama Bank from 2004 through 2007. A. elisabethae has been harvested in The Bahamas for over fifteen years and all of the sites had been harvested three times, including a harvest during the course of the study. Abundances of adult colonies at those sites as well as a location that had not been harvested were also determined. Recruitment was highly variable, differing between sites, transects within sites, and, depending on the site, between years. Recruitment was best correlated with adult abundance averaged across the surrounding site. Regression analyses suggest abundance on smaller scales had only small effects on recruitment. The effects of the harvesting were site specific ranging from a 38 to 67% reduction in the density of mature colonies. The sites with the most abundant A. elisabethae continued to have the highest abundances after harvesting and there was no significant difference in recruitment before and after harvesting. Population size-structure at 6 of 8 sites that have been harvested multiple times exhibited an overall depletion in small colonies suggesting long term suppression of recruitment and declining populations. Severe depression of adult abundances coupled with local recruitment can create a negative feedback and lead to the decline of local populations. Populations that are dependent on self-recruitment are not resilient to large disturbance events.
Project description:<p>Benthic organisms sustain coral reefs through their growth and metabolism, but less is known about how their released metabolites influence reef seawater microorganisms. To investigate metabolite composition of benthic exudates and their ecological significance for reef microbial communities, we harvested exudates from six species of Caribbean benthic organisms including stony corals, octocorals, and an invasive encrusting algae, and subjected these exudates to untargeted and targeted metabolomics approaches using liquid chromatography-mass spectrometry. Incubations with reef seawater microorganisms were conducted to monitor changes in microbial community composition using 16S rRNA gene sequencing and abundance in relation to exudate source and three specific metabolites. Exudates tended to be enriched in amino acids, nucleosides, and vitamins, indicating that benthic organisms contribute labile organic matter to reefs. The phytohormone indole-3-acetic acid was detected in octocoral exudates, suggesting that this metabolite facilitates microbial interactions within and outside of benthic organisms. Exudate compositions were species-specific and significantly enriched in the indole class of metabolites. Microbial abundances and specific microbial taxa responded differently in relation to exudates from stony corals and octocorals, demonstrating the link between benthic organismal composition, metabolite exudates, and microbial growth. Conversely, microbial communities did not respond to additions of the individual metabolites, suggesting that reef microorganisms likely provide diverse metabolite pools that support microbial growth. This work provides novel information about the metabolites released from common Caribbean benthic organisms and indicates that the recent shifts in benthic composition from stony to octocorals alter exudate composition and likely impact microbial community composition and function on coral reefs.</p><p><br></p><p><strong>UPLC-MS Metabolite collection incubation assays</strong> are reported in the current study <strong>MTBLS2855</strong></p><p><strong>UPLC-MS Metabolite uptake incubation assay</strong> is reported in <a href='https://www.ebi.ac.uk/metabolights/editor/study/MTBLS3286' rel='noopener noreferrer' target='_blank'><strong>MTBLS3286</strong></a></p>
Project description:<p>Benthic organisms sustain coral reefs through their growth and metabolism, but less is known about how their released metabolites influence reef seawater microorganisms. To investigate metabolite composition of benthic exudates and their ecological significance for reef microbial communities, we harvested exudates from six species of Caribbean benthic organisms including stony corals, octocorals, and an invasive encrusting algae, and subjected these exudates to untargeted and targeted metabolomics approaches using liquid chromatography-mass spectrometry. Incubations with reef seawater microorganisms were conducted to monitor changes in microbial community composition using 16S rRNA gene sequencing and abundance in relation to exudate source and three specific metabolites. Exudates tended to be enriched in amino acids, nucleosides, and vitamins, indicating that benthic organisms contribute labile organic matter to reefs. The phytohormone indole-3-acetic acid was detected in octocoral exudates, suggesting that this metabolite facilitates microbial interactions within and outside of benthic organisms. Exudate compositions were species-specific and significantly enriched in the indole class of metabolites. Microbial abundances and specific microbial taxa responded differently in relation to exudates from stony corals and octocorals, demonstrating the link between benthic organismal composition, metabolite exudates, and microbial growth. Conversely, microbial communities did not respond to additions of the individual metabolites, suggesting that reef microorganisms likely provide diverse metabolite pools that support microbial growth. This work identifies, quantifies, and compares metabolites released from common Caribbean benthic organisms and indicates that recent shifts in benthic composition from stony to octocorals alter exudate composition and likely impact microbial community composition and function on coral reefs.</p><p><br></p><p><strong>UPLC-MS Metabolite uptake incubation assay</strong> is reported in the current study <strong>MTBLS3286</strong></p><p><strong>UPLC-MS Metabolite collection incubation assays</strong> are reported in <a href='https://www.ebi.ac.uk/metabolights/editor/study/MTBLS2855' rel='noopener noreferrer' target='_blank'><strong>MTBLS2855</strong></a></p>
Project description:BackgroundWhat are the determinant factors of community assemblies in the most diverse ecosystem in the ocean? Coral reefs can be divided in continental (i.e., reefs that develop on the continental shelf, including siliciclastic reefs) and oceanic (i.e., far off the continental shelf, usually on volcanic substratum); whether or not these habitat differences impose community-wide ecological divergence or species exclusion/coexistence with evolutionary consequences, is unknown.MethodsStudying Caribbean octocorals as model system, we determined the phylogenetic community structure in a coral reef community, making emphasis on species coexistence evidenced on trait evolution and environmental feedbacks. Forty-nine species represented in five families constituted the species pool from which a phylogenetic tree was reconstructed using mtDNA. We included data from 11 localities in the Western Caribbean (Colombia) including most reef types. To test diversity-environment and phenotype-environment relationships, phylogenetic community structure and trait evolution we carried out comparative analyses implementing ecological and evolutionary approaches.ResultsPhylogenetic inferences suggest clustering of oceanic reefs (e.g., atolls) contrasting with phylogenetic overdispersion of continental reefs (e.g., reefs banks). Additionally, atolls and barrier reefs had the highest species diversity (Shannon index) whereas phylogenetic diversity was higher in reef banks. The discriminant component analysis supported this differentiation between oceanic and continental reefs, where continental octocoral species tend to have greater calyx apertures, thicker branches, prominent calyces and azooxanthellate species. This analysis also indicated a clear separation between the slope and the remaining habitats, caused by the presence or absence of Symbiodinium. K statistic analysis showed that this trait is conserved as well as the branch shape.DiscussionThere was strong octocoral community structure with opposite diversity and composition patterns between oceanic and continental reefs. Even habitats with similar depths and overall environmental conditions did not share similar communities between oceanic and continental reefs. This indicates a strong regional influence over the local communities, probably due to water transparency differences between major reef types, i.e., oceanic vs. continental shelf-neritic. This was supported by contrasting patterns found in morphology, composition and evolutionary history of the species between atolls and reef banks.
Project description:Oncogenic extrachromosomal DNAs (ecDNA) are common in cancers, but many questions about their origin, structural dynamics and impact on intratumor heterogeneity are still unresolved. Here we describe scEC&T-seq, a method for parallel isolation and sequencing of extrachromosomal circular DNAs and full-length mRNA from single human cells. By applying scEC&T-seq to cancer cells, we not only describe intercellular differences in ecDNA content, but also investigate their structural heterogeneity and transcriptional impact. We reveal that whereas oncogene-containing ecDNA elements are clonally present in cancer cells and drive intercellular oncogene expression differences, other small circular DNAs also captured by scEC&T-seq are mostly private to individual cancer cells, indicating differences in selection and propagation. Moreover, scEC&T-seq uncovers intercellular differences in ecDNA structure, which allowed the inference of ecDNA structural dynamics and point to circular recombination as a potential mechanism of ecDNA evolution. We envision that our method may enable the analysis of yet unknown prerequisites for the maintenance of both small and large circular DNA in cancers, but also in the context of other diseases and normal cellular development.
Project description:The pervasive expression of circular RNA from protein coding loci is a recently discovered feature of many eukaryotic gene expression programs. Computational methods to discover and quantify circular RNA are essential to the study of the mechanisms of circular RNA biogenesis and potential functional roles they may play. In this paper, we present a new statistical algorithm that increases the sensitivity and specificity of circular RNA detection.by discovering and quantifying circular and linear RNA splicing events at both annotated exon boundaries and in un-annotated regions of the genome Unlike previous approaches which rely on heuristics like read count and homology between exons predicted to be circularized to determine confidence in prediction of circular RNA expression, our algorithm is a statistical approach. We have used this algorithm to discover general induction of circular RNAs in many tissues during human fetal development. We find that some regions of the brain show marked enrichment for genes where circular RNA is the dominant isoform. Beyond this global trend, specific circular RNAs are tissue specifically induced during fetal development, including a circular isoform of NCX1 in the developing fetal heart that, by 20 weeks, is more highly expressed than the linear isoform as well as beta-actin. In addition, while the vast majority of circular RNA production occurs at canonical U2 (major spliceosome) splice sites, we find the first examples of developmentally induced circular RNAs processed by the U12 (minor) spliceosome, and an enriched propensity of U12 donors to splice into circular RNA at un-annotated, rather than annotated, exons. Together, our algorithm and its results suggest a potentially significant role for circular RNA in human development. 35 human fetal samples from 6 tissues (3 - 7 replicates per tissue) collected between 10 and 20 weeks gestational time were sequenced using Illumina TruSeq Stranded Total RNA with Ribo-Zero Gold sample prep kit.
Project description:To test the hypothesis that circRNAs might encode functional peptides in mammalian cells, we studied the long intergenic non-protein coding RNA, p53 induced transcript (LINC-PINT), which was previously reported as a tumor suppressor and connected p53 activation with polycomb repressive complex 2 (PRC2). We selected this long noncoding RNA (lncRNA) for further analysis because LINC-PINT has a long exon 2 which in accordance with the bioinformatical analyzed circular RNA standard.The following immunoblotting showed 87aa peptide level also decreased, indicating that this peptide is encoded by circPINTexon2. We name this circRNA encoded peptide PINT87aa. To investigate the possible regulatory role of PINT87aa, we did the expression micro array in PINT87aa stably transfect U251 or U87 glioblastoma cells and their control cells. The array analysis reveals that PINT87aa may involve in the cell cycle regulation, anti-apoptosis effects and multiple oncogenic signaling pathway activation.