Project description:This SuperSeries is composed of the following subset Series: GSE15686: Meta-transcriptome analysis of a natural wheat sourdough ecosystem during a 10-day spontaneous laboratory fermentation (I) GSE15691: Meta-transcriptome analysis of a natural spelt sourdough ecosystem during a 10-day spontaneous laboratory fermentation (I) GSE15692: Meta-transcriptome analysis of a natural spelt sourdough ecosystem during a 10-day spontaneous laboratory fermentation (II) GSE15693: Meta-transcriptome analysis of a natural wheat sourdough ecosystem during a 10-day spontaneous laboratory fermentation (II) Refer to individual Series
Project description:Glaciers are populated by a large number of microorganisms including bacteria, archaea and microeukaryotes. From an ecological point of view, three ecosystems can be differentiated in glaciers: the supraglacial ecosystem, the subglacial ecosystem and the englacial ecosystem. Several factors such as solar radiation, nutrient availability and water content greatly determine the diversity and abundance of microbial populations, the type of metabolism and the biogeochemical cycles. Firstly, the supraglacial ecosystem, sunlit and oxygenated, is predominantly populated by autotrophic microorganisms. Secondly, the subglacial ecosystem contains a majority of chemoautrotophs that are fed on the mineral salts of the rocks and basal soil. Lastly, the englacial ecosystem is the less studied and the one that contains the smallest number of microorganisms. However, these unknown englacial microorganisms establish a true trophic chain and appear to have an active metabolism. In order to study their metabolic potentials, samples of englacial ice were taken from an Antarctic glacier. The cells were harvested and their proteins were extracted and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI/TOF/TOF). Several proteins and enzymes were found that demonstrate the existence of cellular activity at subzero temperatures. In this way it is shown that the englacial microorganisms are not quiescent, but that they maintain an active metabolism and play an important role in the glacial microbial community.
Project description:Glaciers are populated by a large number of microorganisms including bacteria, archaea and microeukaryotes. From an ecological point of view, three ecosystems can be differentiated in glaciers: the supraglacial ecosystem, the subglacial ecosystem and the englacial ecosystem. Several factors such as solar radiation, nutrient availability and water content greatly determine the diversity and abundance of microbial populations, the type of metabolism and the biogeochemical cycles. Firstly, the supraglacial ecosystem, sunlit and oxygenated, is predominantly populated by autotrophic microorganisms. Secondly, the subglacial ecosystem contains a majority of chemoautrotophs that are fed on the mineral salts of the rocks and basal soil. Lastly, the englacial ecosystem is the less studied and the one that contains the smallest number of microorganisms. However, these unknown englacial microorganisms establish a true trophic chain and appear to have an active metabolism. In order to study their metabolic potentials, samples of englacial ice were taken from an Antarctic glacier. The cells were harvested and their proteins were extracted and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI/TOF/TOF). Several proteins and enzymes were found that demonstrate the existence of cellular activity at subzero temperatures. In this way it is shown that the englacial microorganisms are not quiescent, but that they maintain an active metabolism and play an important role in the glacial microbial community.
Project description:Hyperthermophilic bacteria of the genus Thermotoga are known to utilize a wide range of simple and complex polysaccharides. T. maritima's transcriptional response to a variety of mono- and poly-saccharides was previously studied to assign functions to genes involved in carbohydrate uptake and utilization. To compare and contrast closely-related members of the Thermotoga genus, a four-species microarray was developed by expanding a whole genome T. maritima array to include unique genes from three other species (T. neapolitana, T. petrophila, and T. sp. RQ2). This multi-species array was used to investigate the diversity of the genus, specifically the response of each of the four species to a mixture of polysaccharides (galactomannan, glucomannan, xylan, pectin, lichenan, and carboxymethyl cellulose). RNA derived from glucose-grown cultures (glu) was compared to RNA derived from polysaccharide-grown cultures (poly) using a dye swap setup.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level. The labeled aRNA of the sourdough fermentation samples was hybridized using a loop design, i.e. subsequent samples (e.g. 27 h and 51 h, 51 h and 75 h etc.) were hybridized together on the microarray and the loop was closed by hybridizing the last sample with the first.
Project description:Lactic acid bacteria (LAB) are of industrial importance in the production of fermented foods, among which sourdough-derived products. Despite their limited metabolic capacity LAB contribute considerably to important characteristics of fermented foods, among which extended shelf-life, microbial safety, improved texture, and enhanced organoleptic properties. Thanks to the considerable amount of LAB genomic information that became available during the last years, transcriptome, and by extension meta-transcriptome studies, are the exquisite research approaches to study whole ecosystem gene expression into more detail. In this study, microarray analyses were performed using RNA sampled during four 10-day spontaneous sourdough fermentations carried out in the laboratory, namely two wheat and two spelt fermentations with daily back-slopping. Hereto, the in-house developed functional gene LAB microarray was used, representing 406 genes that play a key role in sugar and nitrogen metabolism, functional metabolite production, stress responses and health and safety characteristics. The results reveal the activation of different key metabolic pathways, the ability to use different energy sources, and successful acid and oxidative stress responses. Also, a new algorithm was developed to compute a net expression profile for each of the represented genes, thereby exceeding the species level. The labeled aRNA of the sourdough fermentation samples was hybridized using a loop design, i.e. subsequent samples (e.g. 27 h and 51 h, 51 h and 75 h etc.) were hybridized together on the microarray and the loop was closed by hybridizing the last sample with the first.