Gene profiling of Thalassiosira pseudonana under various growth conditions
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ABSTRACT:
ORGANISM(S): Thalassiosira pseudonana CCMP1335
SUBMITTER: E Armbrust
PROVIDER: E-GEOD-9697 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Publications
Whole-genome expression profiling of the marine diatom Thalassiosira pseudonana identifies genes involved in silicon bioprocesses.
Mock Thomas T Samanta Manoj Pratim MP Iverson Vaughn V Berthiaume Chris C Robison Matthew M Holtermann Karie K Durkin Colleen C Bondurant Sandra Splinter SS Richmond Kathryn K Rodesch Matthew M Kallas Toivo T Huttlin Edward L EL Cerrina Francesco F Sussman Michael R MR Armbrust E Virginia EV
Proceedings of the National Academy of Sciences of the United States of America 20080122 5
Formation of complex inorganic structures is widespread in nature. Diatoms create intricately patterned cell walls of inorganic silicon that are a biomimetic model for design and generation of three-dimensional silica nanostructures. To date, only relatively simple silica structures can be generated in vitro through manipulation of known diatom phosphoproteins (silaffins) and long-chain polyamines. Here, we report the use of genome-wide transcriptome analyses of the marine diatom Thalassiosira p ...[more]
Similar Datasets
Project description:T. pseudonana gene-specific arrays were used for differential gene expression. Seven hundred nine genes were differentially expressed by more than 2-fold (Bayesian t-test, p< 0.001) under at least one growth-limiting condition relative to nutrient-replete conditions. A striking result of the hierarchical cluster analysis was the identification of a common set of genes that were upregulated by both iron and silicon limitation, but no other treatment. Together, these two treatments accounted for about one fourth of all differentially expressed genes but almost two thirds of the differentially expressed novel genes, further emphasizing the distinctive aspects of silicon manipulation in diatoms. We analyzed 6 different sets of arrays from 6 growth conditions. Four biological replicates (=4 arrays) were used for each growth condition.
2010-05-26 | E-GEOD-9660 | biostudies-arrayexpress
Project description:T. pseudonana tiling arrays were used to validate gene models and to predict new genes in the genome of this diatom. The tiling array data validated transcription of about 41% (4,653) of the 11,390 computationally predicted genes. An additional 1,132 transcripts were identified that did not correspond to modeled genes with few of these transcripts (<17%) predicted to encode proteins with homology (e-value < 10-05) to publicly available proteins. These newly identified transcripts have an average length of 1,549 bp, comparable to the average length of the computationally derived genes. Whole genome tiling arrays were conducted under silicon replete and deplete growth conditions to identify new genes involved in the synthesis of the diatom silica cell wall. We analyzed 2 sets of arrays (8 arrays each): one from growth under silicon replete and another one from growth under silicon deplete conditions.
2010-05-26 | E-GEOD-9661 | biostudies-arrayexpress
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:Genes that are constitutively expressed across multiple environmental stimuli are crucial to quantifying differentially expressed genes, particularly when employing quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) assays. However, the identification of these potential reference genes in non-model organisms is challenging and is often guided by expression patterns in distantly related organisms. Here, transcriptome datasets from the diatom Thalassiosira pseudonana grown under replete, phosphorus-limited, iron-limited, and phosphorus and iron co-limited nutrient regimes were analyzed through literature-based searches for homologous reference genes, k-means clustering, and Analysis of Sequence Counts (ASC) to identify putative reference genes. A total of 9759 genes were identified and screened for stable expression. Literature-based searches surveyed 18 generally accepted reference genes, revealing 101 homologs in T. pseudonana with variable expression and a wide range of mean tags per million. K-means analysis parsed the whole transcriptome into 15 clusters. The two most stable clusters contained 709 genes but still had distinct patterns in expression. ASC analyses identified 179 genes that were stably expressed (posterior probability < 0.1 for 1.25 fold change). Genes known to have a stable expression pattern across the test treatments, like actin, were identified in this pool of 179 candidate genes. ASC can be employed on data without biological replicates and was more robust than the k-means approach in isolating genes with stable expression. The intersection of the genes identified through ASC with commonly used reference genes from the literature suggests that actin and ubiquitin ligase may be useful reference genes for T. pseudonana and potentially other diatoms. With the wealth of transcriptome sequence data becoming available, ASC can be easily applied to transcriptome datasets from other phytoplankton to identify reference genes. Axenic T. pseudonana CCMP 1335 was grown at 14°C under 24 hour light (120 µmol photons m-2 s-1) after Dyhrman et al. (2012) in f/2 plus silica chelated media made from surface Sargasso Sea water. Nitrate, silica, vitamins, and trace metals were at f/2 concentrations (Guillard and Ryther 1962), while iron and phosphate were modified across treatments. In brief, triplicate cultures of replete (36 µM PO4, 400 nM Fe), P-limited (0.4 µM PO4, 400 nM Fe), Fe-limited (36 µM PO4, 40 nM Fe), and Co-limited (0.4 µM PO4, 40 nM Fe) treatments were harvested when growth deviated from the replete control. Growth was monitored by cell counts. Biomass was harvested onto 0.2 µm filters and flash frozen in liquid nitrogen and total RNA was extracted as described in Dyhrman et al. (2012). Tag-seq sequencing of the transcriptome was performed by Illumina with a polyA selection and NlaIII digestion, resulting in 21 bp sequence reads or tags (Dyhrman et al., 2012). Libraries were of varied sizes as follows: replete (~12 million), P-limited (~13 million), Fe-limited (~23 million), and Co-limited (~26 million). Tags were mapped to gene models (predicted protein coding regions) with a pipeline designed by Genesifter Inc., requiring 100% identity and covering 9759 genes. Tag counts within a gene were pooled and normalized to the size of the library, with resulting data expressed in tags per million (tpm). Genes with normalized tag counts less than 2.5 tpm for each of the four treatments were excluded (Figure S1) , leaving 7380 genes in the analysis.
2013-01-01 | E-GEOD-40509 | biostudies-arrayexpress
Project description:Transcript levels of all T. pseudonana genes was measured every twelve hours throughout the batch (non-chemostatic) growth of axenic cells grown in large glass bioreactors on a 12hr:12hr dark:light cycle for five days. The data were analyzed to reveal the physiological and regulatory changes that recurred in this diatom when transitioning between dark and light conditions, as well as from exponential phase to stationary, nutrient limited conditions. The longitudinal experiment was performed with two replicates, at 400 and 800ppm CO2. Two growth experiments were conducted, with 10 and 9 longitudinal samples collected from each experiment, respectively. Two-color arrays were used with dye flips for labeling. A common internal reference sample was used for one channel on each array. Expression changes for longitudinal analysis were calculated as the difference from the mean log2 expression ratio for each to the common reference sample, for each gene, over all samples within an experiment. For the analysis of diel states in T. pseudonana, samples from the two series were matched according to the time from innoculation, and divided into four classes: dawn samples (taken at the end of each dark phase), dusk samples (taken at the end of each light phase), exponential samples (the first five samples in each series prior to a drop in growth rate on Day 3), and stationary samples (all samples including following the drop in growth rate on Day 3).
2013-04-18 | E-GEOD-45252 | biostudies-arrayexpress
Project description:Transcriptomic profiling of the diatom Thalassiosira pseudonana at normal and elevlated CO2 levels and at normal and elevated light levels. Common reference total RNA (Agilent Quick-Amp Cy3-labeled) was used in all arrays as an internal standard. Triplicate batch cultures grown at normal (~400ppm) and elevated (~800ppm) CO2 levels, both at i) normal or ii) elevated light levels. Samples were taken during a) exponential and b) stationary growth during all growth experiments. Result: 48 total transcriptomic measurements: [3 parallel replicates] x [400ppm, 800ppm] x [normal light, high light] x [exponential, stationary] x [2 serial replicates]
2015-11-06 | E-GEOD-57737 | biostudies-arrayexpress
Project description:Diatoms are important primary producers in the world’s oceans, yet their growth is constrained in large regions by low bioavailable iron (Fe). Low Fe-induced limitation of primary production is due to requirements for Fe in components of essential metabolic pathways including photosynthesis and other chloroplast plastid functions. Studies have shown that under Fe-limited stress, diatoms alter plastid-specific processes, including components of electron transport. These physiological changes suggest changes of protein content and their abundance within the diatom plastid. While in-silico predictions provide putative information on plastid-localized proteins, knowledge of diatom plastid proteins remains limited in comparison to model photosynthetic organisms. To characterize proteins enriched in diatom plastids we have used shotgun proteomics to assess the proteome of subcellular plastid-enriched fractions from Thalassiosira pseudonana. To improve our understanding of how the plastid proteome is remodeled in response to Fe limitation, proteome sequencing has been performed on T. pseudonana grown under Fe replete and limited conditions. These analyses have shown that Fe limitation regulates major metabolic pathways in the plastid, including the Calvin cycle, as well as changes in light harvesting protein expression. In-silico localization predictions of proteins identified in this plastid-enriched proteome allowed for an in-depth comparison of theoretical vs observed plastid-localization, providing evidence for the potential of additional protein import pathways into the diatom plastid.
2023-08-04 | PXD040824 | Pride
Project description:Comparison of transcriptional profile of Thalassiosira pseudonana exposed for 24h to 36.45 ug/L BaP and methanol-treated controls. Four biological replicates (BaP treatment) and six biological replicates (controls).
2012-02-15 | E-MEXP-3558 | biostudies-arrayexpress
Project description:Diatoms are responsible for ~40% of marine primary productivity1, fueling the oceanic carbon cycle and contributing to natural carbon sequestration in the deep ocean2. Diatoms rely on energetically expensive carbon concentrating mechanisms (CCMs) to fix carbon efficiently at modern levels of CO23–5. How diatoms may respond over the short and long-term to rising atmospheric CO2 remains an open question. Here we use nitrate-limited chemostats to show that the model diatom Thalassiosira pseudonana rapidly responds to increasing CO2 by differentially expressing gene clusters that regulate transcription and chromosome folding and subsequently reduces transcription of photosynthesis and respiration gene clusters under steady-state elevated CO2. These results suggest that exposure to elevated CO2 first causes a shift in regulation and then a metabolic rearrangement. Genes in one CO2-responsive cluster included CCM and photorespiration genes that share a putative cyclic-AMP responsive cis-regulatory sequence, implying these genes are co-regulated in response to CO2 with cAMP as an intermediate messenger. We verified cAMP-induced down-regulation of CCM gene ?-CA3 in nutrient-replete diatom cultures by inhibiting the hydrolysis of cAMP. These results indicate an important role for cAMP in down-regulating CCM and photorespiration genes under elevated CO2 and provide insights into mechanisms of diatom acclimation in response to climate change. In steady-state experiments: axenic T. pseudonana cells in four biological replicates (duplicate chemostats x 2 experimental runs) were acclimated to nitrate-limitation at 70% (1.5 day-1) of max growth rate for >10 days (>15 generations) under continuous light of 80 µmol photons·m?2·s?1. Cell biomass was maintained at ~2 x 105 cells·mL?1 by 10 ?M nitrate and carbonate chemistry stabilized to 300, 475 or 800 ?atm CO2, verified by pH and DIC measurements. Transition samples and carbonate chemistry were collected daily from chemostat cultures as CO2 levels were increased from ~300-800 ?atm at a rate ? 0.2 ?atm·min?1 over four consecutive days (6 generations) after pre-acclimation to 300 ?atm CO2 and nitrate-limitation.
2015-04-17 | E-GEOD-67971 | biostudies-arrayexpress
Project description:Diatom cell walls, made of nanostructured silica, are of interest in diverse areas ranging from cellular structure, to hierarchical organization in biomineralization, to nanotechnology. Thus far, only cell surface proteins and proteins tightly associated with silica matrix have been characterized, and essential components of the silica deposition vesicle (SDV) are unknown, including components of the SDV membrane, cytoskeletal-interacting proteins, and proteins involved in trafficking associated with the SDV. Thus, an understanding of most of the molecular components and the dynamics of cellular processes involved in cell wall synthesis is lacking. In this work we report the first whole-cell response analysis using whole genome microarrays to identify genes potentially involved in diverse aspects of diatom cell division or cell wall synthesis. Thalassiosira pseudonana transcript profiles from precise time points, known to be associated with specific cell wall formation processes in cell-cycle synchronized cultures, suggests that this gene set includes extracellular proteins, silica matrix proteins, and proteins involved in signal transduction, vesicle trafficking, and transport. Protein localization experiments further confirm the first discovery of proteins associated with the SDV membrane. We propose that these proteins provide the interface between extra-SDV organization by the cytoskeleton and intra-SDV organization of silica polymerization determinants, which lead to the higher order organization of diatom silica structure. Analyzed mRNA from 0, 2, 4, 7, 8 and 9 hr of synchronized cell cycle using the Affymetrix GeneChip whole genome tiling array. Initial analysis of gene level expression was performed using Affymetrix Expression Console Software, version 1.1. No biological replicates were performed. 0 hr is used as reference point.
2012-10-01 | E-GEOD-37081 | biostudies-arrayexpress