Project description:Previous molecular and mechanistic studies have identified several principles of prokaryotic transcription, but less is known about the global transcriptional architecture of bacterial genomes. Here we perform a comprehensive study of a cyanobacterial transcriptome, that of Synechococcus elongatus PCC 7942, generated by combining three high-resolution data sets: RNA sequencing, tiling expression microarrays, and RNA polymerase chromatin immunoprecipitation (ChIP) sequencing. We report absolute transcript levels, operon identification, and high-resolution mapping of 5' and 3' ends of transcripts. We identify several interesting features at promoters, within transcripts and in terminators relating to transcription initiation, elongation, and termination. Furthermore, we identify many putative non-coding transcripts. We provide a global analysis of a cyanobacterial transcriptome. Our results uncover insights that reinforce and extend the current views of bacterial transcription. RNA Sequencing of the cyanobacterium Synechococcus elongatus PCC 7942 RNA polymerase ChIP Sequencing of the cyanobacterium Synechococcus elongatus PCC 7942 Tiling Microarray of the cyanobacterium Synechococcus elongatus PCC 7942
Project description:To understand the sensitivity of larval lice to changing environmental parameters we applied a 38K oligo microarray and characterized transcriptome responses after 24 hour exposures to reduced salinity (30-10 parts per thousand (ppt)) or varied temperature (16-4ºC). To further characterize the effects of salinity, we profiled expression changes over a range of seawater with single increment differences (30-25 ppt).
Project description:In order to reveal so far unknown facets of the adaptation of B. subtilis to growth under high-salinity conditions, a whole-transcriptome analysis of B. subtilis BSB (168 Trp+) was performed using strand-specific tiling arrays (tiling step of 22 nucleotides). In addition, the effects of glycine betaine (GB) were analyzed under high salinity and standard growth conditions in a chemically defined medium. Important novel findings were a sustained low-level induction of the SigB-dependent general stress response and strong repression of biofilm matrix genes under high-salinity conditions. GB influences gene expression not only under high-salinity, but also under standard growth conditions without additional salt.
2020-05-18 | GSE145124 | GEO
Project description:Caligus transcriptome exposed to IPath
Project description:To understand the sensitivity of larval lice to changing environmental parameters we applied a 38K oligo microarray and characterized transcriptome responses after 24 hour exposures to reduced salinity (30-10 parts per thousand (ppt)) or varied temperature (16-4M-BM-:C). To further characterize the effects of salinity, we profiled expression changes over a range of seawater with single increment differences (30-25 ppt). Three separate projects. Low resolution salinity (aka wide range or LR_SAL) contains 2 duplicate experiments, each with pools of lice (~500 copepodid lice per beaker; n=3 beakers per condition), incubated for 24 hr at 10M-BM-:C diluted to 30, 25, 20, or 10 parts per thousand (ppt). Temperature study conducted as above, but with a constant salinity of 30 ppt and changed temperature of 4, 10, or 16M-BM-:C. High resolution salinity conducted as above, but with no experiment replication, but with biological repication of n=6 beakers per condition, and with a range of 25, 26, 27, 28, 29, 30 ppt salinity. Please note that each experiment was normalized separately.
Project description:In low rainfall regions soils are naturally conditioned with frequent co-occurrence of salinity and alkalinity. Plant salinity responses both at physiological and molecular level have been extensively researched. However, effects of the combined treatment of alkaline salinity that could greatly reduce plant growth and the mechanisms responsible for tolerance remain indeterminate. In Brassica juncea, large reductions in biomass and increased leaf Na+ concentration under alkaline salinity indicates that the combined treatment had greater negative effect than salinity on both growth and the physiological responses of the plant. To determine molecular mechanisms potentially controlling adaptive tolerance responses to salinity and alkaline salinity, the moderately tolerant genotype NDR 8501 was further investigated using microarray analysis. The transcripts of treated leaf tissues verses those of the untreated control sample were analysed after prolonged stress of four weeks. In total, 528 salinity responsive and 1245 alkaline salinity responsive genes were indentified and only 101 genes were expressed jointly in either of the two treatments. Transcription of 37% more genes involved in response to alkaline salinity than salinity alone, which suggests the increased impact and severity of the combined stress on the plant, indicating the transcription of a far greater number of genes likely involved in mitigation and damage control. Transcription of KUP2 and KUP7 genes involved in potassium homeostasis under salinity alone and NHX1 and ENH1 genes for ion (K+ and Na+) homeostasis under alkaline salinity, clearly demonstrated that different genes and genetic pathways are involved in response to each stress. They further provide supporting evidence for the physiological responses that occur in the plant, with massive reprogramming of the transcriptome leading to partial ion exclusion, shuttling and compartmentation.