Project description:To understand microbial community functional structures of activated sludge in wastewater treatment plants (WWTPs) and the effects of environmental factors on their structure, 12 activated sludge samples were collected from four WWTPs in Beijing. GeoChip 4.2 was used to determine the microbial functional genes involved in a variety of biogeochemical processes. The results showed that, for each gene category, such as egl, amyA, nir, ppx, dsrA sox and benAB, there were a number of microorganisms shared by all 12 samples, suggestive of the presence of a core microbial community in the activated sludge of four WWTPs. Variance partitioning analyses (VPA) showed that a total of 53% of microbial community variation can be explained by wastewater characteristics (25%) and operational parameters (23%), respectively. This study provided an overall picture of microbial community functional structures of activated sludge in WWTPs and discerned the linkages between microbial communities and environmental variables in WWTPs.
Project description:The conventional view is that high temperatures cause microorganisms to replicate slowly or die. In this view, microorganisms autonomously combat heat-induced damage. However, microorganisms co-exist with each other, which raises the underexplored and timely question of whether microorganisms can cooperatively combat heat-induced damages at high temperatures. Here, we use the budding yeast Saccharomyces cerevisiae to show that cells can help each other and their future generations to survive and replicate at high temperatures. As a consequence, even at the same temperature, a yeast population can exponentially grow, never grow or grow after unpredictable durations (hours to days) of stasis, depending on its population density. Through the same mechanism, yeasts collectively delay and can eventually stop their approach to extinction, with higher population densities stopping faster. These features arise from yeasts secreting and extracellularly accumulating glutathione—a ubiquitous heat-damage-preventing antioxidant. We show that the secretion of glutathione, which eliminates harmful extracellular chemicals, is both necessary and sufficient for yeasts to collectively survive at high temperatures. A mathematical model, which is generally applicable to any cells that cooperatively replicate by secreting molecules, recapitulates all of these features. Our study demonstrates how organisms can cooperatively define and extend the boundaries of life-permitting temperatures.
Project description:To understand microbial community functional structures of activated sludge in wastewater treatment plants (WWTPs) and the effects of environmental factors on their structure, 12 activated sludge samples were collected from four WWTPs in Beijing. GeoChip 4.2 was used to determine the microbial functional genes involved in a variety of biogeochemical processes. The results showed that, for each gene category, such as egl, amyA, nir, ppx, dsrA sox and benAB, there were a number of microorganisms shared by all 12 samples, suggestive of the presence of a core microbial community in the activated sludge of four WWTPs. Variance partitioning analyses (VPA) showed that a total of 53% of microbial community variation can be explained by wastewater characteristics (25%) and operational parameters (23%), respectively. This study provided an overall picture of microbial community functional structures of activated sludge in WWTPs and discerned the linkages between microbial communities and environmental variables in WWTPs. Four full-scale wastewater treatment systems located in Beijing were investigated. Triplicate samples were collected in each site.
Project description:To realistically evaluate the effects of the environment in space, it is necessary to understand the effects of external factors during sample transport from Earth to space. The present study focused on temperature, profiling the altered gene expression that develops under low cultivation temperatures in C. elegans, used as a space life science model. The 7903 genes were selected as differentially expressed genes, and divided into five sets with similar expression patterns using k-means clustering. Results from Gene Ontology analysis are significantly indicated that the cell cycle related genes, and the TGFβ/insulin-like signal pathway related genes changed. The TGFβ/insulin-like signal pathway is expected to be activated due to low temperatures, as well as by other stressors.
2009-02-28 | GSE14475 | GEO
Project description:Ative sludge sample in SBR reactor under low temperatures
Project description:To realistically evaluate the effects of the environment in space, it is necessary to understand the effects of external factors during sample transport from Earth to space. The present study focused on temperature, profiling the altered gene expression that develops under low cultivation temperatures in C. elegans, used as a space life science model. The 7903 genes were selected as differentially expressed genes, and divided into five sets with similar expression patterns using k-means clustering. Results from Gene Ontology analysis are significantly indicated that the cell cycle related genes, and the TGFβ/insulin-like signal pathway related genes changed. The TGFβ/insulin-like signal pathway is expected to be activated due to low temperatures, as well as by other stressors. To determine the genes whose expression changed four thermal conditions (10, 15, 20, and 25 °C), DNA microarray analysis was performed. The data consisted of 12 samples, consisting of three biological replicates at each temperature.
Project description:The proteomics study of thermophilic microorganisms in the sludge heat-treated at 75 degrees Celsius, to investigate the heat-resistant enzymes related to the hydrolysis of sludge organic matter.