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PROVIDER: PRJNA1199224 | ENA |
REPOSITORIES: ENA
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Project description:DNA oligonucleotide microarrays were designed with 307 probes for 96 internal transcribed spacer (ITS1, located between 18S and 26S rRNA genes) sequences of known species and strains from the genus Pseudo-nitzschia (Bacillariophyceae). In addition, microarrays also carried 1893 probes targeting ITS1 aequences of marine Crenarchaeota and Alphaproteobacteria of SAR11 clade. In order to assign microarray profiles to Pseudo-nitzschia ribotypes and species and to 'train' the data analysis system, we grew cultures of Pseudo-nitzschia in the laboratory with identities confirmed through rDNA sequence analysis. In total, 9 cultures and 35 environmental water samples were hybridized to microarrays, in some cases, in duplicate or triplicate. Analysis of microarray data allowed us to identify and map Pseudo-nitzschia spp. in the coastal waters along Washington and Oregon coast of the Eastern Pacific Ocean, and to observe seasonal changes in diatom community composition.
2012-06-01 | GSE27141 | GEO
Project description:Here, we examined the ramifications of between-species diversity by documenting the transcriptional response of three marine diatoms - Thalassiosira pseudonana, Fragilariopsis cylindrus, and Pseudo-nitzschia multiseries - to the onset of nitrate limitation of growth, a common limiting nutrient in the ocean. Less than 5% of orthologous genes, shared across the three diatoms, displayed the same transcriptional responses across species when growth was limited by nitrate availability. Orthologs, such as those involved in nitrogen uptake and assimilation, as well as carbon metabolism, were differently expressed across the three species. The two pennate diatoms, F. cylindrus and P. multiseries, shared 3,839 clusters without orthologs in the genome of the centric diatom T. pseudonana. A majority of these pennate-clustered genes, as well as the non-orthologous genes in each species, had minimal annotation information, but were often significantly differentially expressed under nitrate limitation, indicating their potential importance in the response to nitrogen availability. Despite these variations in the specific transcriptional response of each diatom, overall transcriptional patterns suggested that all three diatoms displayed a common physiological response to nitrate limitation that consisted of a general reduction in carbon fixation and carbohydrate and fatty acid metabolism and an increase in nitrogen recycling.
2014-03-25 | GSE56132 | GEO
Project description:Here, we examined the ramifications of between-species diversity by documenting the transcriptional response of three marine diatoms - Thalassiosira pseudonana, Fragilariopsis cylindrus, and Pseudo-nitzschia multiseries - to the onset of nitrate limitation of growth, a common limiting nutrient in the ocean. Less than 5% of orthologous genes, shared across the three diatoms, displayed the same transcriptional responses across species when growth was limited by nitrate availability. Orthologs, such as those involved in nitrogen uptake and assimilation, as well as carbon metabolism, were differently expressed across the three species. The two pennate diatoms, F. cylindrus and P. multiseries, shared 3,839 clusters without orthologs in the genome of the centric diatom T. pseudonana. A majority of these pennate-clustered genes, as well as the non-orthologous genes in each species, had minimal annotation information, but were often significantly differentially expressed under nitrate limitation, indicating their potential importance in the response to nitrogen availability. Despite these variations in the specific transcriptional response of each diatom, overall transcriptional patterns suggested that all three diatoms displayed a common physiological response to nitrate limitation that consisted of a general reduction in carbon fixation and carbohydrate and fatty acid metabolism and an increase in nitrogen recycling. Transcriptomes were collected for diatom cultures harvested at the onset of stationary phase in low nitrate media (55 M-NM-<M NaNO3, 212 M-NM-<M Na2SiO3, 72.4 M-NM-<M NaH2PO4) or during mid-exponential growth in nutrient-replete media (882 M-NM-<M NaNO3, 106 M-NM-<M Na2SiO3, 36.2 M-NM-<M NaH2PO4) in artificial seawater, maintaining three biological replicates per condition and per diatom (N=18). The SOLiD sequencer (version 4) was used to generate the transcriptomes and the SEAStAR software package was used to process the SOLiD reads and to calculate gene counts. Pooled counts for the nitrate-limited treatment were normalized to pooled counts for the nutrient-replete M-bM-^@M-^\controlM-bM-^@M-^] treatment to generate log fold changes in gene transcription using the R software package edgeR from Bioconductor.
2014-03-25 | E-GEOD-56132 | biostudies-arrayexpress
Project description:DNA oligonucleotide microarrays were designed with 307 probes for 96 internal transcribed spacer (ITS1, located between 18S and 26S rRNA genes) sequences of known species and strains from the genus Pseudo-nitzschia (Bacillariophyceae). In addition, microarrays also carried 1893 probes targeting ITS1 aequences of marine Crenarchaeota and Alphaproteobacteria of SAR11 clade. In order to assign microarray profiles to Pseudo-nitzschia ribotypes and species and to 'train' the data analysis system, we grew cultures of Pseudo-nitzschia in the laboratory with identities confirmed through rDNA sequence analysis. In total, 9 cultures and 35 environmental water samples were hybridized to microarrays, in some cases, in duplicate or triplicate. Analysis of microarray data allowed us to identify and map Pseudo-nitzschia spp. in the coastal waters along Washington and Oregon coast of the Eastern Pacific Ocean, and to observe seasonal changes in diatom community composition. Total DNA was isolated from 9 Pseudo-nitzschia laboratory cultures and 35 environmental water samples collected during 7 field campaigns in 2007-2009. The environmental samples were collected at distances of 5 to 55 km from the coast, along the following transects in the Pacific Ocean covering over 300 km of the coastline: La Push (LP), Grays Harbor (GH), Columbia River (CR), and Newport Hydroline (NH). The DNA samples were subjected to PCR amplification with the primers specific for ITS1 sequences. The resultant biotin-labeled target samples were analyzed using microarray hybridization with the CombiMatrix ElectraSense 4X2K format. Out of 44 analyzed samples, 40, 2, and 2 were used for single, duplicate and triplicate hybridizations, respectively.
2012-05-31 | E-GEOD-27141 | biostudies-arrayexpress
Project description:Background: Ocean temperatures are projected to increase over the coming century, with dramatic consequences for the marine biosphere. Diatoms are important contributors to marine primary production and the ocean carbon cycle, yet the molecular mechanisms that regulate their acclimation and adaptation to temperature are poorly understood. Method: Here we use a transcriptomic approach to identify the molecular mechanisms associated with temperature acclimation and adaptation in closely related colder- and warmer-adapted diatom species. Results: We find contrasting patterns of differential expression at sub- and supra-optimal temperatures across the two species, which may be due to adaptive changes in baseline expression. Frontloaded and divested pathways indicate protein processing machinery, membrane structure, and the balance between temperature-independent photosynthesis and temperature-dependent metabolism are key elements of adaptation to temperature changes. Conclusions: Our findings suggest that transcriptional frontloading and divestment may provide a framework to interpret diatom acclimation and adaptation to temperature and success under future warming.
2019-07-31 | GSE125205 | GEO
Project description:Phytoplankton and bacteria form the base of marine ecosystems and their interactions drive global biogeochemical cycles. The effect of bacteria and bacteria-produced compounds on diatoms range from synergistic to pathogenic and can affect the physiology and transcriptional patterns of the interacting diatom. Here, we investigate physiological and transcriptional changes in the marine diatom Thalassiosira pseudonana induced by extracellular metabolites of a known antagonistic bacterium Croceibacter atlanticus. Mono-cultures of C. atlanticus released compounds that inhibited diatom cell division and elicited a distinctive phenotype of enlarged cells with multiple plastids and nuclei, similar to what was observed when the diatom was co-cultured with the live bacteria. The extracellular C. atlanticus metabolites induced transcriptional changes in diatom pathways that include recognition and signaling pathways, cell cycle regulation, carbohydrate and amino acid production, as well as cell wall stability. Phenotypic analysis showed a disruption in the diatom cell cycle progression and an increase in both intra- and extracellular carbohydrates in diatom cultures after bacterial exudate treatment. The transcriptional changes and corresponding phenotypes suggest that extracellular bacterial metabolites, produced independently of direct bacterial-diatom interaction, may modulate diatom metabolism in ways that support bacterial growth.
2022-06-24 | GSE197934 | GEO
Project description:We isolate the cultivable microbiome of a diatom and show that different bacteria have commensal, antagonistic, or synergistic effects on the diatom. One synergistic bacterium enhances growth of the diatom by production of auxin, a phytohormone. The diatom and its synergistic bacterium appear to use auxin and tryptophan as signaling molecules that drive nutrient exchange. Detection of auxin molecules and biosynthesis gene transcripts in the Pacific Ocean suggests that these interactions are widespread in marine ecosystems.
2015-05-29 | GSE65189 | GEO
Project description:The leaf transcriptome of the nickel hyperaccumulator species Homalium kanaliense (Salicaceae) endemic from New caledonia were compared to the closely related non-accumulator Homalium betulifolium, living on Gallery forest or maquis on serpentine soil, to identity differentially expressed genes potentially involved in Ni hyperaccumulation.
2019-06-05 | GSE116052 | GEO
Project description:Background: Marine phytoplankton are responsible for 50% of the CO2 that is fixed annually worldwide and contribute massively to other biogeochemical cycles in the oceans. Diatoms and coccolithophores play a significant role as the base of the marine food web and they sequester carbon due to their ability to form blooms and to biomineralise. To discover the presence and regulation of short non-coding RNAs (sRNAs) in these two important phytoplankton groups, we sequenced short RNA transcriptomes of two diatom species (Thalassiosira pseudonana, Fragilariopsis cylindrus) and validated them by Northern blots along with the coccolithophore Emiliania huxleyi. Results: Despite an exhaustive search, we did not find canonical miRNAs in diatoms. The most prominent classes of sRNAs in diatoms were repeat-associated sRNAs and tRNA-derived sRNAs. The latter were also present in E. huxleyi. tRNA-derived sRNAs in diatoms were induced under important environmental stress conditions (iron and silicate limitation, oxidative stress, alkaline pH), and they were very abundant especially in the polar diatom F. cylindrus (20.7% of all sRNAs) even under optimal growth conditions. Conclusions: This study provides first experimental evidence for the existence of short non-coding RNAs in marine microalgae. Our data suggest that canonical miRNAs are absent from diatoms. However, the group of tRNA-derived sRNAs seems to be very prominent in diatoms and coccolithophores and may be used for acclimation to environmental conditions.
2015-03-06 | GSE57987 | GEO
Project description:Background: Marine phytoplankton are responsible for 50% of the CO2 that is fixed annually worldwide and contribute massively to other biogeochemical cycles in the oceans. Diatoms and coccolithophores play a significant role as the base of the marine food web and they sequester carbon due to their ability to form blooms and to biomineralise. To discover the presence and regulation of short non-coding RNAs (sRNAs) in these two important phytoplankton groups, we sequenced short RNA transcriptomes of two diatom species (Thalassiosira pseudonana, Fragilariopsis cylindrus) and validated them by Northern blots along with the coccolithophore Emiliania huxleyi. Results: Despite an exhaustive search, we did not find canonical miRNAs in diatoms. The most prominent classes of sRNAs in diatoms were repeat-associated sRNAs and tRNA-derived sRNAs. The latter were also present in E. huxleyi. tRNA-derived sRNAs in diatoms were induced under important environmental stress conditions (iron and silicate limitation, oxidative stress, alkaline pH), and they were very abundant especially in the polar diatom F. cylindrus (20.7% of all sRNAs) even under optimal growth conditions. Conclusions: This study provides first experimental evidence for the existence of short non-coding RNAs in marine microalgae. Our data suggest that canonical miRNAs are absent from diatoms. However, the group of tRNA-derived sRNAs seems to be very prominent in diatoms and coccolithophores and may be used for acclimation to environmental conditions. RNA-seq study of sRNA populations in two species of diatoms using Illumina GAII high-throughput sequencing
2015-03-06 | E-GEOD-57987 | biostudies-arrayexpress