Measurement of genome-wide gene expression in cyanobacteria grown under simluated natural light conditions
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ABSTRACT:
ORGANISM(S): Synechococcus elongatus PCC 7942 = FACHB-805
PROVIDER: GSE104204 | GEO | 2017/12/16
SECONDARY ACCESSION(S): PRJNA412026
REPOSITORIES: GEO
Similar Datasets
Project description:We used RNA sequencing to measure genome-wide gene expression in the cyanobacterium Synechococcus elongatus PCC 7942 grown under dynamic light regimes that mimic the variation in light intensity seen on a Clear Day in nature, or the rapid changes in light intensity that accompany changes in shading We compare these gene expression dynamics to those of a culture grown under a Low Light condition that mimics the standard laboratory conditions used for study of cyanobacteria. Our analysis reveals that naturally relevant light conditions drastically modify gene expression dynamics in cyanobacteria Notably, the expression of circadian clock-controlled genes is responsive to changes in light intensity, showing modulated dynamics that can allow cyanobacteria to adapt their metabolism to changing environmental conditions
2017-12-16 | GSE104203 | GEO
Project description:We used ChIP sequencing to measure genome-wide binding of transcription factors in the cyanobacterium Synechococcus elongatus PCC 7942 grown under dynamic light regimes that mimic the rapid changes in light intensity that accompany changes in shading. Our analysis reveals that rapid changes in light intensity modulate the binding of RNA polymerase (RNAP) upstream of genes in a way that correlates with changes in downstream gene expression, suggesting that changes in transcriptional regulation control light-responsive gene expression changes. Also, binding of the circadian clock-controlled transcription factor RpaA and the light-responsive transcription factor RpaB change upstream of genes in a manner correlating with RNAP enrichment and downstream gene expression. This suggests that changes in RpaA and RpaB binding upstream of genes regulate the light-responsive expression of genes in cyanobacteria.
2017-12-16 | GSE104202 | GEO
Project description:Measurement of genome-wide gene expression in cyanobacteria grown under simluated natural light conditions
| PRJNA412026 | ENA
Project description:Measurement of genome-wide gene expression in cyanobacteria grown under simluated natural light conditions [RNA-Seq]
| PRJNA412032 | ENA
Project description:Measurement of transcription factor binding in cyanobacteria grown under simluated natural light conditions [ChIP-Seq]
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Project description:Harmful cyanobacterial blooms in freshwater ecosystems are closely associated with changes in the composition of symbiotic microbiomes, water quality, and environmental factors. In this work, the relationship between two representative harmful cyanobacterial species (Anabaena sp. and Microcystis sp.) and their associated bacterial assemblages were investigated using a 16S rRNA-based meta-amplicon sequencing analysis during a large-scale cultivation of cyanobacteria under different light conditions with limited wavelength ranges (natural light, blue-filtered light, green-filtered light, and dark conditions). During the cultivation periods, the growth pattern of cyanobacteria and bacterial composition of the phycosphere considerably varied in relation to light restrictions. Unlike other conditions, the cyanobacterial species exhibited significant growth during the cultivation period under both the natural and the blue light conditions. Analyses of the nitrogenous substances revealed that nitrogen assimilation by nitrate reductase for the growth of cyanobacteria occurred primarily under natural light conditions, whereas nitrogenase in symbiotic bacteria could also be activated under blue light conditions. Sphingobium sp., associated with nitrogen assimilation via nitrogenase, was particularly dominant when the cell density of Microcystis sp. increased under the blue light conditions. Thus, cyanobacteria could have symbiotic relationships with ammonium-assimilating bacteria under light-limited conditions, which aids the growth of cyanobacteria.
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Project description:Hypoxia is an important nongenotoxic stress that modulates the tumor suppressor activity of p53 during malignant progression. In this study, we investigated how genotoxic and nongenotoxic stresses regulate p53 association with chromatin, p53 transcriptional activity, and p53-dependent apoptosis. We found that genotoxic and nongenotoxic stresses result in the accumulation and binding of the p53 tumor suppressor protein to the same cognate binding sites in chromatin. However, it is the stress that determines whether downstream signaling is mediated by association with transcriptional coactivators. In contrast to p53 induced by DNA-damaging agents, hypoxia-induced p53 has primarily transrepression activity. Using extensive microarray analysis, we identified families of repressed targets of p53 that are involved in cell signaling, DNA repair, cell cycle control, and differentiation. Following our previous study on the contribution of residues 25 and 26 to p53-dependent hypoxia-induced apoptosis, we found that residues 25-26 and 53-54 and the polyproline- and DNA-binding regions are also required for both gene repression and the induction of apoptosis by p53 during hypoxia. This study defines a new role for residues 53 and 54 of p53 in regulating transrepression and demonstrates that 25-26 and 53-54 work in the same pathway to induce apoptosis through gene repression.
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Project description:The accumulation and production of biochemical compounds in microalgae are influenced by available light quality and algal species-specific features. In this study, four freshwater cryptophyte strains (Cryptomonas ozolinii, C. pyrenoidifera, C. curvata, and C. sp. (CPCC 336)) and one marine strain (Rhodomonas salina) were cultivated under white (control), blue, and green (experimental conditions) lights. Species-specific responses to light quality were detected, i.e., the color of light significantly affected cryptophyte biomass productivity and biochemical compositions, but the optimal light for the highest chemical composition with high antioxidant capacity was different for each algal strain. Overall, the highest phycoerythrin (PE) content (345 mg g-1 dry weight; DW) was reached by C. pyrenoidifera under green light. The highest phenolic (PC) contents (74, 69, and 66 mg g-1 DW) were detected in C. curvata under control conditions, in C. pyrenoidifera under green light, and in C. ozolinii under blue light, respectively. The highest exopolysaccharide (EPS) content (452 mg g-1 DW) was found in C. curvata under the control light. In terms of antioxidant activity, the biochemical compounds from the studied cryptophytes were highly active, with IC50 -values < 50 µg mL-1. Thus, in comparison to well-known commercial microalgal species, cryptophytes could be considered a possible candidate for producing beneficial biochemical compounds.
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