Systems-level Responses to Salinity and Temperature Variations in the Marine Bacterium Vibrio natriegens
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ABSTRACT:
ORGANISM(S): Vibrio natriegens
PROVIDER: GSE184146 | GEO | 2021/09/18
REPOSITORIES: GEO
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Project description:Vibrio natriegens is a rapidly growing salt marsh bacterium that is being developed as a synthetic biology chassis. We characterized its physiological response to different salinities and temperatures in order to optimize culturing conditions and understand its adaptations to a salt marsh environment. Using metabolomics, transcriptomics, and proteomics we determined what pathways respond to these environmental parameters. We found that organic osmolyte synthesis and membrane transporters were most responsive to changes in salinity. The primary osmolytes were glutamate, glutamine, and ectoine, responding to salinity across temperature treatments. However, when media was supplemented with choline, glycine betaine seemed to mostly replace ectoine. These results provide a baseline dataset of metabolic activity under a variety of conditions that will inform decisions made about culturing and genome engineering for future applications.
2021-09-15 | PXD027874 | Pride
Project description:Organisms across all kingdoms of life use small organic molecules called osmolytes to adapt to diverse environmental conditions and preserve viability. Osmolytes are thought to thermally stabilise proteins based on in vitro studies of a few purified proteins. The molecular mechanisms of osmolytes remain controversial and systematic global studies of osmolyte action within a complex cellular milieu are so far lacking. Here we present an in situ proteome-wide analysis of protein thermal stabilisation by osmolytes, covering all major classes of these molecules: trimethylamine N-oxide (TMAO), betaine, glycerol, proline, trehalose and glucose. Using a structural proteomics approach, we systematically probed the effects of osmolytes on protein thermal stability, native structures, and aggregation, thus revealing widespread mechanisms of osmolyte action, but also osmolyte- and protein- specific effects. All tested osmolytes stabilised the majority of the proteome. The stabilisation of most proteins could be explained by the preferential exclusion model, according to which osmolytes unfavourably interact with protein backbones thus promoting folded states. We also detected specific protein-osmolyte binding events which resulted in strong thermal stabilisation, although binding was not necessary for stabilisation. Aggregation of most proteins occurred at higher temperatures in the presence of osmolytes than in their absence. TMAO however promoted aggregation of small, unfolded proteins but also showed the strongest protein thermal stabilisation effects, which might reflect adaptation to the extreme living conditions of marine organisms that accumulate TMAO. Our global in situ analysis provides mechanistic insight into how osmolytes function within a complex biological matrix. Our data further provides a resource to guide the design or selection of stabilisers for protein-based drugs and the identification of conditions that increase thermotolerance of microorganisms in biotechnological applications.
2024-08-09 | PXD036186 | Pride
Project description:Betaine critically contributes to the control of hepatocellular hydration and provides protection of the liver from different kinds of stress. This study investigates to what extent hepatocellular hydration changes affect the expression levels of enzymes involved in the metabolism of betaine and related organic osmolytes by using qRT-PCR gene expression studies in rat hepatoma cells as well as metabolic and gene expression profiling in 5,10 - methylene tetrahydrofolate reductase (MTHFR) deficient primary hepatocytes. The results demonstrate a coordinated regulation of betaine degradation and synthesis under anisoosmotic conditions. Expression of betaine degrading enzymes is downregulated by hyperosmolarity and strongly induced by hypoosmolarity. In contrast, synthesis of glycerophosphocholine from phosphoethanolamine and conversion of choline to betaine are both induced by hyperosmolarity but decreased under hypoosmotic conditions. In addition we evaluated the flux of choline and its derivates in liver and plasma of methylene tetrahydrofolate reductase knockout (Mthfr-/-) mice by tandem mass spectrometry. Analyses of system-wide alterations of osmolyte metabolism with microarray studies revealed expression changes similar to those after hypoosmotic exposure in this betaine depletion model. In conclusion, regulation of betaine synthesis and degradation and concomitant changes in intracellular osmolyte concentrations contribute to long-term adaptation to anisoosmotic exposure of the liver. Expression of 280 genes were analyzed in wild type and mthr-/- mice (n=7) with spotted oligonucleotides.
2013-04-01 | E-GEOD-42275 | biostudies-arrayexpress
Project description:Betaine critically contributes to the control of hepatocellular hydration and provides protection of the liver from different kinds of stress. This study investigates to what extent hepatocellular hydration changes affect the expression levels of enzymes involved in the metabolism of betaine and related organic osmolytes by using qRT-PCR gene expression studies in rat hepatoma cells as well as metabolic and gene expression profiling in 5,10 - methylene tetrahydrofolate reductase (MTHFR) deficient primary hepatocytes. The results demonstrate a coordinated regulation of betaine degradation and synthesis under anisoosmotic conditions. Expression of betaine degrading enzymes is downregulated by hyperosmolarity and strongly induced by hypoosmolarity. In contrast, synthesis of glycerophosphocholine from phosphoethanolamine and conversion of choline to betaine are both induced by hyperosmolarity but decreased under hypoosmotic conditions. In addition we evaluated the flux of choline and its derivates in liver and plasma of methylene tetrahydrofolate reductase knockout (Mthfr-/-) mice by tandem mass spectrometry. Analyses of system-wide alterations of osmolyte metabolism with microarray studies revealed expression changes similar to those after hypoosmotic exposure in this betaine depletion model. In conclusion, regulation of betaine synthesis and degradation and concomitant changes in intracellular osmolyte concentrations contribute to long-term adaptation to anisoosmotic exposure of the liver.
2013-04-01 | GSE42275 | GEO
Project description:Alkaliphilic microorganisms are similar to mesophilic counterparts with exception to membrane proteins. Detection of membrane proteins is difficult due to hydrophobicity and low absolute abundance. Caldalkalibacillus thermarum TA2.A1 is of interest due to growth from pH 7.5 to pH 10. Combination of whole cell lysate proteomics and membrane extracts solubilized with either SDS or FOS-choline-12 detected 158 membrane proteins, including a complete electron transport chain. Additionally, transporters for osmolytes ectoine and glycine betaine were observed.
2023-07-11 | PXD042369 | Pride
Project description:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses”, “modulation of respiratory chain and related components”, and “ion homeostasis”. A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity respectively, and repressed by temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of temperature. Low salinity induced genes involved in “protein-folding-stress response”, suggesting disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by temperature. However, salt-induced cell motility was reduced at high temperature, possibly caused by an alteration of Na+ permeability by temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. In addition, compared to low salinity external iron increased hydroxyectoine accumulation by 20% at high salinity, but reduced the intracellular content of ectoines by 50% at high salinity plus high temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens
2018-08-31 | GSE69612 | GEO
Project description:Populations that tolerate extreme environmental conditions with frequent fluctuations can give valuable insights into physiological limits and adaptation. In some estuarine and marine ecosystems, organisms must adapt to extreme and fluctuating salinities, but not much is known how varying salinities impact local adaptation across a wide geographic range. We used eight geographically and genetically divergent populations of the intertidal copepod Tigriopus californicus to test if northern populations have greater tolerance to low salinity stresses, as they experience greater precipitation and less evaporation. We used a common garden experiment approach and exposed all populations to acute low (1, 3ppt) and high (110, 130ppt) salinities for 24 hours, and a fluctuation between baseline salinity and moderate low (7ppt) and high (80ppt) salinities over 49 hours. We also performed RNA-sequencing at several time points during the fluctuation between baseline and 7ppt to understand the molecular basis of divergence between two populations with differing physiological responses. We present these novel findings: 1) acute low salinity conditions caused more deaths than high salinity, 2) molecular processes that elevate proline levels increased in 7ppt, which contrasts with other T. californicus studies that mainly associated accumulation of proline with hyperosmotic stress. We also find that 3) tolerance to a salinity fluctuation did not follow a latitudinal trend, but was instead governed by a complex interplay of factors including population and the duration of salinity stress. This highlights the importance of including a wider variety of environmental conditions in empirical studies to understand local adaptation.
2021-02-12 | GSE166634 | GEO
Project description:This model is the first of Chromohalobacter canadensis. The pathways for PHB mtabolism, and osmoprotectants (ectoine, betaine, choline) were curated.
2022-09-27 | MODEL2204110001 | BioModels
Project description:Introduction: A major economic impediment to the aquaculture of marine finfish in land-based recirculating systems is maintaining the system salinity at a range for optimal growth. Florida Pompano (Trachinotus carolinus) are warm water, euryhaline, marine finfish shown to be a suitable candidate for low-salinity culture. Due to its popularity among sport and commercial fishers, high market value, and ability to readily consume pelleted feeds, the Florida Pompano has become a renewed target for commercialized aquaculture. Although the Florida Pompano has been successfully grown at various salinities, its optimal growth salinity has not yet been established. Studies have shown culturing at different salinities has an effect on digestion rates, feed utilization, and lipid biosynthesis. Identifying the optimal salinity for growth would result in decreased energy expenditure on maintaining homeostasis, since osmoregulation is a highly demanding process. This would allow for energy to be spent on the efficient use of nutrients. Methods: Our study was designed to determine how Florida Pompano larviculture at various salinities affects fish health with transcriptomics (RNA-seq) and fatty acid analysis. RNA-seq was used to identify genes actively transcribed and expressed at the time of sampling. After hatching in a salinity of ~ 30 ppt, larvae were reared in 345 L tanks at one of three salinities (10, 20, 30 ppt) in triplicate. Larvae samples for RNA-seq and fatty acid analysis were collected every three days until weaning. Samples for fatty acid composition were analyzed using a gas chromatography-mass spectrometry (GC/MS). RNA was extracted from homogenized whole-body samples using the Qiagen RNeasy Mini kit. Total RNA was sequenced on the Illumina HiSeq 4000 System. Raw sequences were filtered for low-quality sequences, aligned to the S. dumerili reference genome (NCBI Genome: 12614), and quantified. Each sampling day was compared across salinities to establish the differentially expressed genes (DEGs) between salinities. Results & Discussion: The numbers of DEGS in pooled samples was minimal (less than 15 total in each comparison) and the number of DEGS at each dph was variable. There were no significant differences between pooled samples or at each dph according to PERMANOVA analysis, but each dph was statistically different on pairwise analysis. Gene set enrichment analysis revealed that there was a downregulation of immune related genes in lower salinities versus higher salinities suggesting larvae may be dealing with less stress at lower salinities. Most osmoregulation, fatty acid, and immune related genes tested were not significantly different across salinities. This is likely be cause the Florida pompano is euryhaline and has a tolerance to the salinities selected. There was an increase in the expression levels of several immune related genes that may indicate an increase exposure to pathogens at later days post hatch likely related to feeding schedule. There was also an increase in fatty acid biosynthesis genes that corresponded with levels of fatty acids indicating a possible synthesis of essential fatty acids from precursors. Conclusions: From a transcriptomics perspective, the larvae did not show a negative response to lower salinities in comparison to higher salinities, which in fact showed upregulation of immune related genes. Further exploration of Florida pompano’s ability to biosynthesize essential fatty acids is necessary. This study will help enable the optimization of Florida Pompano larviculture using information on the optimal salinity and fatty acid content for growth and facilitate more cost-effective rearing methods.
2022-12-01 | GSE190968 | GEO
Project description:Salinity is a major factor that can affect greatly the viability of the fish larvae during their developing stages. Natural populations are exposed to high fluctuation in the environmental conditions. Also, salinity management is of high relevance in hatcheries. The objective of this study was to determine the biological effects of environmental salinities on larval development in sole. Larvae were exposed to two salinities, 10 and 36 ppt, from eggs until the 3 days after hatching. Expression profiles were determined using RNA-seq, microarray and validated using qPCR. Important malformations were identified. The identification of key molecular pathways affected by salinity can help to understand the effects of salinity during early developmental stages with a profound impact to evaluate the effects of climate change and improve hatchery practices.
2016-04-24 | GSE57173 | GEO