Mechanisms underlying turgor regulation in the estuarine algaVaucheria erythrospora(Xanthophyceae) exposed to hyperosmotic shock

2015 ◽  
Vol 38 (8) ◽  
pp. 1514-1527 ◽  
Author(s):  
ABISHEK MURALIDHAR ◽  
LANA SHABALA ◽  
PAUL BROADY ◽  
SERGEY SHABALA ◽  
ASHLEY GARRILL
Keyword(s):  
Hyperosmotic Shock ◽  
Turgor Regulation

Short-term volume and turgor regulation in yeast

2008 ◽  
Vol 45 ◽  
pp. 147-160 ◽  
Author(s):  
Jörg Schaber ◽  
Edda Klipp
Keyword(s):  
Dynamic Model ◽  
Volume Change ◽  
Volume Regulation ◽  
Time Course ◽  
Osmotic Shock ◽  
Intracellular Concentration ◽  
Short Term ◽  
Hydrodynamic Property ◽  
Turgor Regulation ◽  
Thermodynamic Framework

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.

Ultrastructural Characterization of Malpighian Tubules of Rhodnius prolixus During the Insect's Feeding Cycle and Under Hyperosmotic Shock

2020 ◽  
Vol 129 (2) ◽  
pp. 189
Author(s):  
Jacenir Reis dos Santos-Mallet ◽  
Simone Patrícia Carneiro Freitas ◽  
Maria Luiza Ribeiro de Oliveira ◽  
Alice Helena Ricardo-Silva ◽  
Aníbal Gil Lopes ◽  
...  
Keyword(s):  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Hyperosmotic Shock ◽  
Ultrastructural Characterization ◽  
Feeding Cycle

scholarly journals Visualization of Chromatin in the Yeast Nucleus and Nucleolus Using Hyperosmotic Shock

2021 ◽  
Vol 22 (3) ◽  
pp. 1132
Author(s):  
Nicolas Thelen ◽  
Jean Defourny ◽  
Denis L. J. Lafontaine ◽  
Marc Thiry
Keyword(s):  
Osmotic Shock ◽  
Size Composition ◽  
Yeast Cells ◽  
Exponential Growth Phase ◽  
Cell Nuclei ◽  
Hyperosmotic Shock ◽  
Christmas Trees ◽  
Transmission Electron ◽  
Active Transcription ◽  
Decondensed Chromatin

Unlike in most eukaryotic cells, the genetic information of budding yeast in the exponential growth phase is only present in the form of decondensed chromatin, a configuration that does not allow its visualization in cell nuclei conventionally prepared for transmission electron microscopy. In this work, we studied the distribution of chromatin and its relationships to the nucleolus using different cytochemical and immunocytological approaches applied to yeast cells subjected to hyperosmotic shock. Our results show that osmotic shock induces the formation of heterochromatin patches in the nucleoplasm and intranucleolar regions of the yeast nucleus. In the nucleolus, we further revealed the presence of osmotic shock-resistant DNA in the fibrillar cords which, in places, take on a pinnate appearance reminiscent of ribosomal genes in active transcription as observed after molecular spreading (“Christmas trees”). We also identified chromatin-associated granules whose size, composition and behaviour after osmotic shock are reminiscent of that of mammalian perichromatin granules. Altogether, these data reveal that it is possible to visualize heterochromatin in yeast and suggest that the yeast nucleus displays a less-effective compartmentalized organization than that of mammals.

scholarly journals Down-regulation of TORC2-Ypk1 signaling promotes MAPK-independent survival under hyperosmotic stress

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Alexander Muir ◽  
Françoise M Roelants ◽  
Garrett Timmons ◽  
Kristin L Leskoske ◽  
Jeremy Thorner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Molecular Basis ◽  
Open Channel ◽  
Hyperosmotic Stress ◽  
Channel State ◽  
Dependent Protein Kinase ◽  
Hyperosmotic Shock ◽  
Dependent Protein ◽  
Intracellular Glycerol

In eukaryotes, exposure to hypertonic conditions activates a MAPK (Hog1 in Saccharomyces cerevisiae and ortholog p38 in human cells). In yeast, intracellular glycerol accumulates to counterbalance the high external osmolarity. To prevent glycerol efflux, Hog1 action impedes the function of the aquaglyceroporin Fps1, in part, by displacing channel co-activators (Rgc1/2). However, Fps1 closes upon hyperosmotic shock even in hog1∆ cells, indicating another mechanism to prevent Fps1-mediated glycerol efflux. In our prior proteome-wide screen, Fps1 was identified as a target of TORC2-dependent protein kinase Ypk1 (<xref ref-type="bibr" rid="bib30">Muir et al., 2014</xref>). We show here that Fps1 is an authentic Ypk1 substrate and that the open channel state of Fps1 requires phosphorylation by Ypk1. Moreover, hyperosmotic conditions block TORC2-dependent Ypk1-mediated Fps1 phosphorylation, causing channel closure, glycerol accumulation, and enhanced survival under hyperosmotic stress. These events are all Hog1-independent. Our findings define the underlying molecular basis of a new mechanism for responding to hypertonic conditions.

scholarly journals Two tonoplast MATE proteins function as turgor-regulating chloride channels inArabidopsis

2017 ◽  
Vol 114 (10) ◽  
pp. E2036-E2045 ◽  
Author(s):  
Haiwen Zhang ◽  
Fu-Geng Zhao ◽  
Ren-Jie Tang ◽  
Yuexuan Yu ◽  
Jiali Song ◽  
...  
Keyword(s):  
Chloride Channels ◽  
Ectopic Expression ◽  
Root Hairs ◽  
Large Family ◽  
Patch Clamp Recording ◽  
Mesophyll Cells ◽  
Environmental Signals ◽  
Turgor Regulation ◽  
Cell Turgor ◽  
Definition Of

The central vacuole in a plant cell occupies the majority of the cellular volume and plays a key role in turgor regulation. The vacuolar membrane (tonoplast) contains a large number of transporters that mediate fluxes of solutes and water, thereby adjusting cell turgor in response to developmental and environmental signals. We report that two tonoplast Detoxification efflux carrier (DTX)/Multidrug and Toxic Compound Extrusion (MATE) transporters, DTX33 and DTX35, function as chloride channels essential for turgor regulation inArabidopsis. Ectopic expression of each transporter inNicotiana benthamianamesophyll cells elicited a large voltage-dependent inward chloride current across the tonoplast, showing that DTX33 and DTX35 each constitute a functional channel. Both channels are highly expressed inArabidopsistissues, including root hairs and guard cells that experience rapid turgor changes during root-hair elongation and stomatal movements. Disruption of these two genes, either in single or double mutants, resulted in shorter root hairs and smaller stomatal aperture, with double mutants showing more severe defects, suggesting that these two channels function additively to facilitate anion influx into the vacuole during cell expansion. In addition,dtx35single mutant showed lower fertility as a result of a defect in pollen-tube growth. Indeed, patch-clamp recording of isolated vacuoles indicated that the inward chloride channel activity across the tonoplast was impaired in the double mutant. Because MATE proteins are widely known transporters of organic compounds, finding MATE members as chloride channels expands the functional definition of this large family of transporters.

scholarly journals Analysis of novel hyperosmotic shock response suggests ‘beads in liquid’ cytosol structure

Biology Open ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. bio044529 ◽  
Author(s):  
Alexander I. Alexandrov ◽  
Erika V. Grosfeld ◽  
Alexander A. Dergalev ◽  
Vitaly V. Kushnirov ◽  
Roman N. Chuprov-Netochin ◽  
...  
Keyword(s):  
Hyperosmotic Shock ◽  
Shock Response

scholarly journals Loss of the F-Actin Binding and Vesicle-Associated Protein Comitin Leads to a Phagocytosis Defect

2002 ◽  
Vol 1 (6) ◽  
pp. 906-914 ◽  
Author(s):  
Thomas Schreiner ◽  
Martina R. Mohrs ◽  
Rosemarie Blau-Wasser ◽  
Alfred von Krempelhuber ◽  
Michael Steinert ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Gene Replacement ◽  
Actin Binding ◽  
Wild Type ◽  
Hyperosmotic Shock ◽  
Latex Beads ◽  
Knockout Mutants ◽  
Mutant Cells

ABSTRACT Comitin is an F-actin binding and membrane-associated protein from Dictyostelium discoideum, which is present on Golgi and vesicle membranes and changes its localization in response to agents affecting the cytoskeleton. To investigate its in vivo functions we have generated knockout mutants by gene replacement. Based on comitin's in vitro functions we examined properties related to vesicular transport and microfilament function. Whereas cell growth, pinocytosis, secretion, chemotaxis, motility, and development were unaltered, comitin-lacking cells were impaired in the early steps of phagocytosis of Saccharomyces cerevisiae particles and of Escherichia coli, whereas uptake of latex beads was unaffected. Furthermore, the lack of comitin positively affected survival of pathogenic bacteria. Mutant cells also showed an altered response to hyperosmotic shock in comparison to the wild type. The redistribution of comitin during hyperosmotic shock in wild-type cells and its presence on early phagosomes suggest a direct involvement of comitin in these processes.

scholarly journals Electrophysiology of Turgor Regulation in Marine Siphonous Green Algae

2006 ◽  
Vol 211 (1) ◽  
pp. 1-14 ◽  
Author(s):  
M.A. Bisson ◽  
M.J. Beilby ◽  
V.A. Shepherd
Keyword(s):  
Green Algae ◽  
Turgor Regulation

scholarly journals Manganese Suppresses the Haploinsufficiency of Heterozygous trpy1Δ/TRPY1 Saccharomyces cerevisiae Cells and Stimulates the TRPY1-Dependent Release of Vacuolar Ca2+ under H2O2 Stress

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 79 ◽  
Author(s):  
Lavinia Ruta ◽  
Ioana Nicolau ◽  
Claudia Popa ◽  
Ileana Farcasanu
Keyword(s):  
Oxidative Stress ◽  
Saccharomyces Cerevisiae ◽  
Cellular Response ◽  
Trp Channels ◽  
Homozygous Deletion ◽  
Growth Defect ◽  
Mechanical Stimuli ◽  
Hyperosmotic Shock ◽  
Diploid Cells ◽  
In Cells

Transient potential receptor (TRP) channels are conserved cation channels found in most eukaryotes, known to sense a variety of chemical, thermal or mechanical stimuli. The Saccharomyces cerevisiae TRPY1 is a TRP channel with vacuolar localization involved in the cellular response to hyperosmotic shock and oxidative stress. In this study, we found that S. cerevisiae diploid cells with heterozygous deletion in TRPY1 gene are haploinsufficient when grown in synthetic media deficient in essential metal ions and that this growth defect is alleviated by non-toxic Mn2+ surplus. Using cells expressing the Ca2+-sensitive photoprotein aequorin we found that Mn2+ augmented the Ca2+ flux into the cytosol under oxidative stress, but not under hyperosmotic shock, a trait that was absent in the diploid cells with homozygous deletion of TRPY1 gene. TRPY1 activation under oxidative stress was diminished in cells devoid of Smf1 (the Mn2+-high-affinity plasma membrane transporter) but it was clearly augmented in cells lacking Pmr1 (the endoplasmic reticulum (ER)/Golgi located ATPase responsible for Mn2+ detoxification via excretory pathway). Taken together, these observations lead to the conclusion that increased levels of intracytosolic Mn2+ activate TRPY1 in the response to oxidative stress.

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