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: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
Project description:The comparision between gradual ocean acidification (GC) and one way ocean acidification (HC) of physiological and molecular responses on diatom Skeletonema costatum
Project description:Nearly all cellular processes are pH dependent. The acidic pH inside the lysosome (vacuole in yeast) is essential for cellular content degradation, signaling, and autophagy. Defect in lysosome/vacuole acidification is a conserved hallmark of aging and age-related diseases. Traditionally, lysosome/vacuole is thought to import free protons (H⁺) from the surrounding neutral cytosol. In this study, we uncovered a previously unrecognized, conserved lysosome/vacuole acidification mechanism, involving lysosomal/vacuolar uptake of H+ pumped out by mitochondrial electron transport chain through membrane contacts between mitochondria and lysosomes/vacuoles. Aging/senescence-associated disruption of mitochondria-lysosome/vacuole contacts causes lysosomal/vacuolar de-acidification, which can be reversed by expressing a linker to connect these organelles and through an asymmetry-dependent rejuvenation process in daughter cells. Preserving lysosomal acidification in senescent human cells prevents the induction of major senescence-associated secretory phenotype factors and enhances autophagic flux. These findings reshape our current understanding of the mechanisms underlying lysosomal/vacuolar (de-)acidification in both young and aged/senescent cells.
Project description:Several remodeling of intracellular environments has been identified in senescent cells, including enlargement of cell / nuclear size and intracellular acidification. Although these alterations of intracellular environments were reported to be involved in unique characteristics of senescent cells, the contribution of intracellular acidification to senescence-associated cellular phenotypes is poorly understood. Here, we identified that upregulation of TXNIP and its paralog ARRDC4 as a hallmark of intracellular acidification in addition to KGA-type GLS1. These genes were also upregulated in response to senescence-associated intracellular acidification. Neutralization of the intracellular acidic environment ameliorated not only senescence-related upregulation of TXNIP, ARRDC4, and KGA, but also inflammation-related genes, possibly through suppression of glycolysis. Taken toghether, our data implied that the contribution of intracellular pH to senescence-associated cellular features, such as SASP.
Project description:Extracellular acidosis is a common feature of multiple pathological microenvironments, such as ischemia, tumors, inflammation, metabolic dysregulation, and tissue injury. Astrocytes are central regulators of brain homeostasis and are highly responsive to changes in extracellular pH. However, transcriptomic resources comparing different experimentally induced acidotic conditions in astrocytes remain limited. Here, we generated an RNA sequencing dataset for the mouse astrocyte cell line C8-D1A exposed to three extracellular acidification-related conditions, including lactic acid treatment, 15% CO2 exposure, and NaHCO3-low medium, together with untreated controls. This dataset captures both shared and condition-specific transcriptomic responses of astrocytes under distinct extracellular acidification paradigms. Functional enrichment analyses highlighted biological pathways related to stress response, metabolism, inflammatory signaling, and cellular adaptation to extracellular acidification. This RNA-seq dataset provides a useful resource for studying astrocyte responses to different forms of extracellular acidotic stress and may facilitate the identification of common and distinct molecular programs associated with acidification-relevant cellular states.