Project description:Functional profiles predicted based on taxonomic affiliations differed from those obtained by GeoChip microarray analysis, which separated community functional capacity based on plant location. The identified metabolic pathways provided insight regarding microbial strategies for colonization and survival in these ecosystems. Sixteen samples analyzed.
Project description:Functional profiles predicted based on taxonomic affiliations differed from those obtained by GeoChip microarray analysis, which separated community functional capacity based on plant location. The identified metabolic pathways provided insight regarding microbial strategies for colonization and survival in these ecosystems.
Project description:Microbial sulfur cycling and chemoautotrophy are focal points of research in cold seeps. However, limited culture-dependent and in-situ studies have described the biological features and ecological significance of chemoautotrophic sulfur-oxidizing bacteria. In this study, we isolated Guyparkeria hydrothermalis SP2, a thiosulfate/sulfide-oxidizing chemoautotrophic bacterium, from cold-seep sediment. Electron microscopy, Raman spectroscopy, and stoichiometry confirmed the efficient production of zero-valent sulfur (ZVS) by G. hydrothermalis SP2. Genomic, transcriptomic, and qRT-PCR analyses revealed its utilization of the Sox pathway for thiosulfate oxidation and the fccB gene for sulfide oxidation. Its chemoautotrophic capability mediated by the Calvin-Benson-Bassham (CBB) cycle was identified through isotopic and qRT-PCR analyses. In-situ studies demonstrated its ability to produce ZVS by oxidizing sulfide in cold seeps, with a preference for different genes compared to those under laboratory conditions. Metagenomic and metatranscriptomic analyses indicated the ubiquity of its sulfur oxidation-based chemoautotrophic pathway in cold seep sediments. Therefore, this strain holds significance for investigating sulfur oxidation-based chemoautotrophic pathways in cold seeps.
Project description:Temperature stress is a survival challenge that biological cells may encounter at any time. To sustain normal metabolic activities, organisms have gradually evolved strategies to respond promptly to temperature changes. The two-component system, typically involved in regulating the transcription of relevant genes in response to environmental stimuli, consists of a histidine kinase and a response regulator. This system mediates environmental signal transduction in microbial cells. This study identified DhqSR as a novel temperature-sensing two-component system in Thermus thermophilus HB27. It regulates the expression of type II 3-dehydroquinate dehydratase (DHQase) in the aromatic amino acid biosynthesis pathway, indirectly controlling aromatic amino acid synthesis and thereby altering cellular thermal adaptation capabilities.
Project description:This project aims to find the molecular changes driving the cold stress response of freshwater amphipods with different overwintering strategies
Project description:Homeothermic vertebrates exposed to low temperature challenge activate multiple central and physiological pathways in order to regain homeostatic balance within the new environmental constrains. Such homeostatic responses include shivering and non-shivering thermogenesis, altered carbohydrate and lipid metabolism and protein catabolism synchronized by neuroendocrine responses. Pending their evolutionary life history, some of these physiological responses were also identified in poikilothermic vertebrates, yet a conception of heat seeking behavior and lack of cold-related metabolic regulation prevails. Using various physiological parameters and hypothalamic transcriptome analysis in the tropical poikilotherm Nile tilapia, we now demonstrate that cold stress in a poikilotherm induce complex central and physiological homeostatic responses. We further show that oxytocin which is a known thermoregulator in homeotherms, actively regulates temperature related homeostasis in poikilotherms. Moreover, we show that pharmacological or genetic blockage of oxytocin signaling affects oxygen-dependent metabolic rate in two cold exposed poikilothermic models. Therefore, our study identifies oxytocin as an adaptive and evolutionarily conserved metabolic regulator and show that poikilotherms brain actively respond to cold temperature stress by regulating metabolic physiology.
Project description:Drought represents a significant stress to microorganisms and is known to reduce microbial activity and organic matter decomposition in Mediterranean ecosystems. However, we lack a detailed understanding of the drought stress response of microbial decomposers. Here we present metatranscriptomic data on the physiological response of in situ microbial communities on plant litter to long-term drought in Californian grass and shrub ecosystems.
