Search results for "Osmotic"
showing 10 items of 156 documents
Specific stress-induced storage of trehalose, glycerol and D-arabitol in response to oxidative and osmotic stress in Candida albicans.
2012
Candida albicans exponential yeast cells are able to face environmental challenges by mounting a rapid and efficient "general stress response". Here we show that one of the main components of this response consists of the intracellular protective accumulation of the non-reducing disaccharide trehalose and two polyols, glycerol and D-arabitol, an accumulation that occurs in a stress-specific dependent manner. Thus, oxidative exposures promoted a marked increase in both trehalose and D-arabitol in the wild type strain, RM-100, whereas the glycerol content remained virtually unaffected with respect to basal levels. In contrast, osmotic challenges induced the significant storage of glycerol acc…
The yeast osmosensitive mutant fps1Δ transformed by the cauliflower BobTIP1;1 aquaporin withstand a hypo-osmotic shock
2005
AbstractOsmoregulation plays an important role in cellular responses to osmotic stress in plants and in yeast. Aquaporins contribute to osmotic adjustment by facilitating transport of water or solutes across membranes. The tonoplastic water channel BobTIP1;1 (original name BobTIP26-1) genes are upregulated during dessication stress in cauliflower meristematic tissue. To investigate the physiological importance of BobTIP1;1, we expressed it in a Saccharomyces cerevisiae osmosensitive mutant fps1Δ. We showed that the defect in the yeast glycerol plasma membrane transporter is complemented by a plant cDNA encoding the aquaporin BobTIP1;1 which is localized in the vacuolar membrane of the compl…
Msb2 is a Ste11 membrane concentrator required for full activation of the HOG pathway.
2015
The high osmolarity glycerol (HOG) pathway, composed of membrane-associated osmosensors, adaptor proteins and core signaling kinases, is essential for the survival of yeast cells under hyper-osmotic stress. Here, we studied how the MAPKKK Ste11 might change its protein interaction profile during acute stress exposure, with an emphasis on the sensory system of the so-called Sho1/Msb2 signaling branch. To characterize the transience of protein-protein interactions we utilized a recently described enzymatic in vivo protein proximity assay (M-track). Accordingly, interaction signals between Ste11 and many of its signaling partners can already be detected even under basal conditions. In most cas…
The role of glycerol transporters in yeast cells in various physiological and stress conditions.
2015
Small and uncharged glycerol is an important molecule for yeast metabolism and osmoadaptation. Using a series of S. cerevisiae BY4741-derived mutants lacking genes encoding a glycerol exporter (Fps1p) and/or importer (Stl1p) and/or the last kinase of the HOG pathway (Hog1p), we studied their phenotypes and various physiological characteristics with the aim of finding new roles for glycerol transporters. Though the triple mutant hog1Δ stl1Δ fps1Δ was viable, it was highly sensitive to various stresses. Our results showed that the function of both Stl1p and Fps1p transporters contributes to the cell ability to survive during the transfer into the state of anhydrobiosis, and that the deletion …
Induction and tolerization of anti-male CD8+ cytotoxic T lymphocytes by in vivo immunization with an H-Y-derived peptide
1999
Abstract We have analyzed the immune response induced by a 9mer synthetic peptide derived from the male histocompatibility antigen H-Y and containing D b -binding motifs in C57BL/6 mice. In this study we report that a single, subcutaneous injection of the peptide emulsified in IFA gave rise to the development of male-specific CD8 + T cells which displayed H-Y-specific proliferative response in vitro and showed a Tc1-type pattern of cytokine production (i.e. they secreted IFN-γ and IL-2, but not IL-4 and IL-10). Development of a strong cytotoxic activity required in vitro stimulation with specific peptide and IL-2: under these culture conditions, we were able to generate potent CD8 + CTLs th…
The Saccharomyces cerevisiae zinc finger proteins Msn2p and Msn4p are required for transcriptional induction through the stress response element (STR…
1996
The MSN2 and MSN4 genes encode homologous and functionally redundant Cys2His2 zinc finger proteins. A disruption of both MSN2 and MSN4 genes results in a higher sensitivity to different stresses, including carbon source starvation, heat shock and severe osmotic and oxidative stresses. We show that MSN2 and MSN4 are required for activation of several yeast genes such as CTT1, DDR2 and HSP12, whose induction is mediated through stress-response elements (STREs). Msn2p and Msn4p are important factors for the stress-induced activation of STRE dependent promoters and bind specifically to STRE-containing oligonucleotides. Our results suggest that MSN2 and MSN4 encode a DNA-binding component of the…
Boosting the performance of a Reverse Electrodialysis – Multi-Effect Distillation Heat Engine by novel solutions and operating conditions
2019
Abstract This work presents a performance analysis of a waste-heat-to-power Reverse Electrodialysis Heat Engine (RED-HE) with a Multi-Effect Distillation (MED) unit as the regeneration stage. The performance of the system is comparatively evaluated using two different salts, sodium chloride and potassium acetate, and investigating the impact of different working solutions concentration and temperature in the RED unit. For both salt solutions, the impact of membrane properties on the system efficiency is analysed by considering reference ionic exchange membranes and high-performing membranes. Detailed mathematical models for the RED and MED units have been used to predict the thermal efficie…
An experimental and constitutive investigation on the chemo-mechanical behaviour of a clay
2013
Engineering issues for which the understanding of the chemo-mechanical behaviour of soils is relevant include wellbore stability problems, the salinification of groundwater, and nuclear waste storage. However, despite the vast number of situations in which couplings between chemistry and mechanics occur, the available constitutive models rely on limited experimental evidence. This paper presents the results of an experimental programme on the chemo-mechanical behaviour of a non-swelling illite. The osmotic suction is controlled through the ion concentration of sodium chloride in the pore water. Stress paths include mechanical loading at a constant osmotic suction, and an increasing osmotic …
Immune-inflammatory and metabolic effects of high dose furosemide plus hypertonic saline solution (HSS) treatment in cirrhotic subjects with refracto…
2016
Introduction Patients with chronic liver diseases are usually thin as a result of hypermetabolism and malnutrition expressed by reduced levels of leptin and impairment of other adyponectins such as visfatin. Aims We evaluated the metabolic and inflammatory effects of intravenous high-dose furosemide plus hypertonic saline solutions (HSS) compared with repeated paracentesis and a standard oral diuretic schedule, in patients with cirrhosis and refractory ascites. Methods 59 consecutive cirrhotic patients with refractory ascites unresponsive to outpatient treatment. Enrolled subjects were randomized to treatment with intravenous infusion of furosemide (125-250mg⁄bid) plus small volumes of HSS …
Evolution of osmosensing signal transduction in Metazoa: stress-activated protein kinases p38 and JNK.
2001
Sponges (Porifera) represent the most basal branch of the Metazoa alive today. We show that two central stress-activated protein kinases involved in the osmosensing pathway, p38 mitogen-activated protein kinase (MAPK) and JNK, can complement for the ancestral MAPK Hog1 in the yeast Saccharomyces cerevisiae. S. cerevisiae mutants lacking Hog1 (hog1-Delta 1) have been complemented with the sponge SDJNK and SDp38 genes. Western blotting has revealed that, after transformation, the hog1-Delta 1+ SDJNK(sense) and hog1-Delta 1+ SDp38(sense) clones express the sponge proteins. Functional studies have demonstrated that the complemented clones grow under hyperosmotic conditions (0.6 M NaCl). Further…