Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification This experiment is part of a much larger experiment. We have produced 4 454 metatranscriptomic datasets and 6 454 metagenomic datasets. These were derived from 4 samples. The experiment is an ocean acidification mesocosm set up in a Norwegian Fjord in 2006. We suspended 6 bags containing 11,000 L of sea water in a Coastal Fjord and then we bubbled CO2 through three of these bags to simulate ocean acidification conditions in the year 2100. The other three bags were bubbled with air. We then induced a phytoplankton bloom in all six bags and took measurements and performed analyses of phytoplankton, bacterioplankton and physiochemical characteristics over a 22 day period. We took water samples from the peak of the phytoplankton bloom and following the decline of the phytoplankton bloom to analyses using 454 metagenomics and 454 metatranscriptomics. Day 1, High CO2 Bag and Day 1, Present Day Bag, refer to the metatranscriptomes from the peak of the bloom. Day 2, High CO2 Bag and Day 2, Present Day Bag, refer to the metatranscriptomes following the decline of the bloom. Obviously High CO2 refers to the ocean acidification mesocosm and Present Day refers to the control mesocosm. Raw data for both the metagenomic and metatranscriptomic components are available at NCBI's Short Read Archive at ftp://ftp.ncbi.nlm.nih.gov/sra/Studies/SRP000/SRP000101
Project description:Nodularia spumigena is a toxic, filamentous cyanobacterium capable to fix atmospheric N2, which is often dominating cyanobacterial bloom events in the Baltic Sea and other brackish water systems worldwide. Phosphate (P) limitation has been considered as one environmental parameter that is somehow promoting the establishment of cyanobacterial mass developments. In the present study, we analyzed the response of the N. spumigena strain CCY9914 towards strong P limitation in an experimental approach. Filaments of N. spumigena were incubated under P-replete and P-deplete conditions for 21 days. Samples for RNA-seq were collected after 7 and 14 days. Growth of the strain was diminished under P-deplete conditions, however, filaments contained more polyphosphate under P-deplete compared to P-replete conditions. High polyphosphate contents were also detected within heterocysts. After 7 days, approximately 100 genes were upregulated in P-deplete filaments, among them was a high proportion of genes encoding proteins related to P-homeostasis such as transport systems for different P species. Many of these genes became also up-regulated after 14 days compared to 7 days in filaments grown under P-replete conditions, which was consistent with the almost complete consumption of dissolved P in these cultures after 14 days. In addition to genes directly related to P starvation, for example genes encoding proteins for bioactive compound synthesis, gas vesicle formation, or sugar catabolism were stimulated under the P-deplete conditions. Collectively, our data permitted to describe an experimentally validated P-stimulon in N. spumigena CCY9914 and provide evidence that severe P limitation could indeed support bloom formation by this filamentous strain.
Project description:Fresh water microbial communities from LaBonte Lake, Laramie, Wyoming, sample from algal/cyanobacterial bloom material peak-bloom 1 metagenome
Project description:Fresh water microbial communities from LaBonte Lake, Laramie, Wyoming, sample from algal/cyanobacterial bloom material peak-bloom 2 metagenome