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PROVIDER: PRJNA1207608 | ENA |
REPOSITORIES: ENA
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Project description:Atrazine is one of the most commonly used herbicide and has been frequently detected in estuarine and offshore waters worldwide. As a photosystem Ⅱ inhibitor, atrazine may inhibit phytoplankton from fixating of CO2 and alter its carbon metabolism, which will undoubtedly have negative effect on the primary productivity and carbon sequestration capacity of coastal waters. However, the existing reports mainly focused on agriculture and freshwater ecosystems and are mostly toxicity test with high-dose of atrazine, which have little concern about the negative effects of atrazine on the carbon metabolism of phytoplankton and can’t reflect the actual toxic situation in offshore water. Diatoms are widely distributed in freshwater and oceans and contribute at least 20% of the global CO2 assimilation, which is an ideal model group to assess the ecological risk of atrazine. Here we present a comprehensive analysis of the physiological and genome-wide gene expression characteristics of the diatom P. tricornutum Pt-1 (CCMP 2561) treated with environmental dose of atrazine at different stress stages.
2020-12-12 | GSE112478 | GEO
Project description:In summer 2014, we conducted experiments to determine the effects of different N substrates on phytoplankton communities in the North Pacific Ocean and in the transition zone of the California Current and gyre (Shilova, Mills et al., 2017). Samples were incubated with nitrate, ammonium, urea, and filtered deep water (FDW) for 48 hours (T48). Two treatments added iron, alone (Fe) or with a mix of N substrates (N+Fe), to determine the effects of Fe on the utilization of N substrates. All treatments resulted in changes in phytoplankton cell abundances and photosynthetic activity at both locations, with differences between phytoplankton groups. Prochlorococcus had large increases in biomass in response to ammonium and urea, while both eukaryotic phytoplankton and Synechococcus had only modest biomass increases in response to N+Fe and FDW. Moreover, distinct physiological responses were observed within sub-populations of Prochlorococcus and Synechococcus. In order to understand the variable responses to N substrates among phytoplankton groups and sub-populations in the California Current transition zone, the present work examines transcriptional changes that occurred 24 h after the substrates were added. Specifically, we hypothesize that transcription changes at 24 h indicate which phytoplankton taxa are N-limited, and thus help explain changes in cell abundances and photosynthetic activity by individual phytoplankton groups observed at 48 h. Furthermore, we hypothesize that the diversity in physiological responses within Prochlorococcus and Synechococcus are evident in the transcriptional responses measured at sub-population resolution.
2020-04-12 | GSE130464 | GEO
Project description:Marine phytoplankton are a diverse group of photoautotrophic organisms and key mediators in the global carbon cycle. Phytoplankton physiology and biomass accumulation are closely tied to mixed layer depth, but the intracellular metabolic pathways activated in response to changing mixed layer depths remain unexplored. Here, metatranscriptomics was used to characterize the phytoplankton community response to a mixed layer shallowing from 233 meters to 5 meters over the course of two days during the late spring in the Northwest Atlantic. Most phytoplankton genera downregulated core photosynthesis, carbon storage, and carbon fixation genes as the system transitioned from a deep to a shallow mixed layer and shifted towards catabolism of stored carbon ic pathways supportive of rapid cell growth. In contrast, phytoplankton genera exhibited divergent transcriptional strategies for photosystem light harvesting complex genes during this transition. Active infection, taken as the ratio of virus to host transcripts, increased in the Bacillariophyta (diatom) phylum and decreased in the Chlorophyta (green algae) phylum upon mixed layer shallowing. A conceptual model is proposed to provide ecophysiological context for our findings, in which light limitation during deep mixing induces populations into a transcriptional state which maximizes interrupts the oscillating levels of transcripts related to photosynthesis, carbon storage, and carbon fixation found in shallow mixed layers with relatively higher growth rates. We propose that upon sensing high light levels during mixed layer shallowing, phytoplankton resume diel oscillation of core sets of genes enabling photoprotection, biosynthesis and cell replication. Our findings highlight the shared and unique transcriptional response strategies within phytoplankton communities acclimating to the dynamic light environment associated with transient deep mixing and shallowing events during the annual North Atlantic bloom.
2023-03-22 | GSE208287 | GEO
Project description:Atrazine is an agricultural herbicide used throughout the Midwestern United States that frequently contaminates potable water supplies resulting in human exposure. Using the zebrafish model system, an embryonic atrazine exposure was previously reported to decrease spawning rates with an increase in progesterone and ovarian follicular atresia in adult females. In addition, alterations in genes associated with distinct molecular pathways of the endocrine system were observed in brain and gonad tissue of the adult females and males. Current hypotheses for mechanistic changes in the developmental origins of health and disease include genetic (e.g., copy number alterations) or epigenetic (e.g., DNA methylation) mechanisms. As such, in the current study we investigated whether an atrazine exposure would generate copy number alterations (CNAs) in the zebrafish genome. A zebrafish fibroblast cell line was used to limit detection to CNAs caused by the chemical exposure. First, cells were exposed to a range of atrazine concentrations and a crystal violet assay was completed, showing confluency decreased by ~60% at 46.3 µM. Cells were then exposed to 0, 0.463, 4.63, or 46.3 µM atrazine and array comparative genomic hybridization completed. Results showed 34, 21, and 44 CNAs in the 0.463, 4.63, and 46.3µM treatments, respectively. Furthermore, CNAs were associated with previously reported gene expression alterations in adult male and female zebrafish. This study demonstrates that atrazine exposure can generate CNAs that are linked to gene expression alterations observed in adult zebrafish exposed to atrazine during embryogenesis providing a mechanism of the developmental origins of atrazine endocrine disruption.
2017-02-20 | GSE93635 | GEO
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals.
2014-12-22 | GSE64286 | GEO
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3)
2014-12-22 | GSE64368 | GEO
Project description:rs05-05_atrazine - effect of atrazine and sucrose on arabidopsis transcriptome - Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana seedlings, under conditions of in vitro culture, a very high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors (Sulmon et al., 2004). The CATMA investigation will be useful to reveal the gene networks implicated in the mechanisms of xenobiotics tolerance. - Seeds of Arabidopsis thaliana (ecotype Columbia) were surface-sterilized inbayrochlore/ethanol (1:1, v/v), rinsed in absolute ethanol and dried overnight. Germination and growth were carried out under axenic conditions in square Petri dishes. After seeds were sowed, Petri dishes were placed at 4degreeC for 48 h in order to break dormancy and homogenize germination, and then transferred to a control growth chamber at 22degreeC under a 16-h light period regime at 4500 lux for 4 weeks. Growth medium consisted of 0.8% (w/v) agar in 1x Murashige and Skoog (MS) basal salt mix (Sigma, St. Louis, MO, USA) adjusted to pH 5.7. After 4 weeks of cultivation on vertical plates plantlets were transferred on fresh medium complemented or not with atrazine 10 uM and with sucrose 80mM or mannitol 80 mM which were directly added during preparation of agar-MS media prior to sterilisation. Atrazine was sterilized by microfiltration through 0.2 um cellulose acetate filters (Polylabo, Strasbourg, France) and then axenically added to melted agar-MS medium prior to pouring into Petri dishes. Then plantlets were harvested after 24 hours of transfer and extracted for RNA. Keywords: treated vs untreated comparison
2007-05-31 | GSE7942 | GEO
Project description:Enhanced vertical stratification brought about by warming of the ocean surface is expected to reduce vertical circulation and nutrient input with knock-on effects for phytoplankton. Increased nutrient limitation is one predicted outcome, but the response of phytoplankton is uncertain because long-term adaptation to nutrient limitation has not been studied. We used Cu as a model catalytic nutrient to explore the adaptive response of an oceanic diatom to continuous nutrient deprivation. Thalassiosira oceanica was maintained under Cu-limiting and sufficient conditions for more than 2000 generations and the evolved populations evaluated for physiological traits in a reciprocal transplant experiment. Adaptation to low Cu concentration increased Cu use efficiency, so that under Cu-limiting conditions T. oceanica maintained significantly faster rates of net C assimilation and growth than the control and ancestral populations.
2021-11-19 | GSE188999 | GEO