20-Hydroxyecdysone-induced changes in the cell volume of lepidopteran cells associated with population dynamics

In Vitro ◽  
1984 ◽  
Vol 20 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Leigh H. English ◽  
Barbara K. Magelky ◽  
Edwin P. Marks
Keyword(s):  
Population Dynamics ◽  
Cell Volume ◽  
Induced Changes

Changes in Astroglial Cell Volume after Exposure to HgCl2 or CH3HgCl

1992 ◽  
Vol 20 (2) ◽  
pp. 246-250
Author(s):  
Lars Rönnbäck ◽  
Elisabeth Hansson
Keyword(s):  
Glucose Uptake ◽  
Cell Volume ◽  
Receptor Agonist ◽  
Primary Cultures ◽  
Control Cell ◽  
Astroglial Cell ◽  
Receptor Stimulation ◽  
Adrenoceptor Agonists ◽  
Β Receptor ◽  
Induced Changes

Cell volume was determined by measuring [14C]-3- O-methyl glucose uptake in astroglial-enriched primary cultures. Control cell volume was 3.20μl/mg protein. After incubation in 10 5M HgCl2 for 60 minutes, there was a 71% increase in cell volume. This increase was partially inhibited in the presence of the α1 receptor agonist, phenylephrine, or by the α2 receptor agonist clonidine, and was completely reversible by their respective antagonists, prazosine and yohimbine. The β receptor agonist, isoproterenol, which in itself increased cell volume, and 5-hydroxytryptamine (5HT) did not affect the HgCl2-induced changes in cell volume. 10 5M CH3HgCl increased cell volume by 26% after 30 minutes of incubation. This increase was not significantly influenced by adrenoceptor agonists or 5HT. It therefore seems that mercurial-induced changes in cell volume can be regulated by astroglial receptor stimulation.

Cell volume-induced changes in K+ transport across the rat colon

2001 ◽  
Vol 171 (4) ◽  
pp. 445-458 ◽  
Author(s):  
R. Ribeiro ◽  
B. Heinke ◽  
M. Diener
Keyword(s):  
Cell Volume ◽  
Rat Colon ◽  
Induced Changes ◽  
K Transport

Volume-sensitive Ca influx and release from intracellular pools in gastric parietal cells

1992 ◽  
Vol 263 (3) ◽  
pp. C584-C589 ◽  
Author(s):  
P. A. Negulescu ◽  
B. Munck ◽  
T. E. Machen
Keyword(s):  
Image Processing ◽  
Cell Volume ◽  
Digital Image Processing ◽  
Parietal Cells ◽  
Cell Swelling ◽  
Cell Shrinkage ◽  
Gastric Glands ◽  
Intact Rabbit ◽  
Induced Changes ◽  
Gastric Parietal Cells

The effects of osmotically induced changes in cell volume on cytoplasmic free Ca (Cai) were studied in parietal cells from intact rabbit gastric glands using digital image processing of fura-2 fluorescence. In resting unstimulated cells, Cai was unaffected by either cell swelling or shrinking when osmolarity was varied between 200 and 400 mosM (isotonicity 290 mosM). However, when cells were swelled in a 165 mosM solution (55% tonicity), a biphasic Ca increased was observed. On average, Cai increased transiently from 80 to 218 nM before stabilizing at approximately 140 nM. The peak was due to release from intracellular pools because it was present in Ca-free solutions while the sustained elevation was dependent on external Ca. In carbachol-stimulated cells, Ca influx was most sensitive to cell shrinkage. For example, addition of 25 mM sucrose (108% tonicity) caused a 30% decrease in the sustained carbachol-stimulated Cai increase (plateau). In contrast, carbachol-stimulated cells were relatively insensitive to cell swelling, with a 30% decrease in tonicity causing only a 15% increase in the plateau. However, as in the unstimulated cells, extreme (55% tonicity) swelling caused additional increases in Cai levels. The carbachol-dependent effects of changes in cell volume on Cai could be mimicked by treating cells with thapsigargin, an inhibitor of Ca pumps of intracellular membranes that also has been shown to stimulate Ca entry. Thus, although extreme swelling conditions (55% tonicity) could elicit Cai increases in either the presence or absence of agonist, agonist was required to observe Cai decreases due to cell shrinkage.(ABSTRACT TRUNCATED AT 250 WORDS)

Biofilm Architectural Breakdown in Response to Antibiotics Facilitates Community Invasion

2020 ◽  
Author(s):  
Francisco Diaz-Pascual ◽  
Knut Drescher
Keyword(s):  
Single Cell ◽  
Cell Volume ◽  
Metabolic Effects ◽  
Matrix Composition ◽  
Bacterial Cells ◽  
Isolated Cells ◽  
Matrix Cell ◽  
Biofilm Architecture ◽  
And Function ◽  
Induced Changes

<p>Bacterial cells are often exposed to stress by changes in their environment. During the last decades the response of isolated cells to stress has been investigated in great detail. By contrast, little is known about the emergent multicellular level responses to stress, such as antibiotic exposure. Studying responses at the community level is key to understand the structure and function of the most common bacterial state: the multicellular communities termed biofilms. Here, by analysing <em>Vibrio cholerae</em> biofilms exposed to all different classes of antibiotics with single-cell resolution, we found that inhibition of protein synthesis cause striking changes in cell volume and biofilm architecture. The observed changes in cell volume are a single-cell level response driven by metabolic effects of the translational inhibition. The multicellular-level responses result from changes in matrix composition, matrix-cell dissociation and mechanical properties of the biofilms. We observed that these antibiotic-induced changes in biofilm architecture have strong consequences on the ecological dynamics of biofilms by making biofilms prone to invasion by bacteriophages and other bacterial cells. These mechanistic and ecological consequences of the emergent group-level architectural response to antibiotics are important to fully understand the ecological succession of biofilms and the implications of antibiotic therapy.</p>

Na-K-Cl cotransport in the shark rectal gland. II. Regulation in isolated tubules

1992 ◽  
Vol 262 (4) ◽  
pp. C1009-C1017 ◽  
Author(s):  
C. Lytle ◽  
B. Forbush
Keyword(s):  
Cell Volume ◽  
Specific Binding ◽  
Rectal Gland ◽  
Cell Water ◽  
Cell Shrinkage ◽  
Camp Content ◽  
Hormonal Modulation ◽  
Cl Channels ◽  
Induced Changes ◽  
Extracellular Sodium

We examined the binding of [3H]benzmetanide, a potent inhibitor of Na-K-Cl cotransport, to secretory tubules isolated from dogfish shark rectal glands. Specific binding increased dramatically (from 3 to 40 pmol/mg protein) when the tubules were exposed to secretory stimuli [e.g., vasoactive intestinal peptide, adenosine, forskolin, and permeable adenosine 3',5'-cyclic monophosphate (cAMP) analogues]. Binding was also promoted by osmotically induced changes in cell volume; a 45% reduction in cell water content mimicked the effect of secretagogues on binding, whereas a 40% increase in cell water was only half as effective. Volume-responsive binding required extracellular sodium and chloride. The effect of cell shrinkage on binding was rapid and reversible (half-activation time = approximately 3 min, half-deactivation time = approximately 2 min). The binding sites evoked by secretagogues and by cell shrinkage had similar affinities for [3H]benzmetanide (Kd approximately 0.35 microM). Forskolin, a potent secretagogue, increased cell cAMP content 10-fold and respiration 7-fold, whereas hypertonicity affected neither parameter. The effects of cAMP-dependent stimuli and hypertonicity on binding were not additive. These results suggest the following. 1) Na-K-Cl cotransporters acquire the ability to bind [3H]benzmetanide with high affinity when activated. 2) Hormonal modulation of rectal gland secretion involves a coordinated regulation of basolateral Na-K-Cl cotransporters and apical Cl channels. 3) Separate signal transduction pathways, one sensitive to cAMP and another to cell volume, regulate the Na-K-Cl cotransporter.

Experimental evidence of an electronic transition in CeP under pressure using Ce L3 XAS

2017 ◽  
Vol 19 (27) ◽  
pp. 17526-17530 ◽  
Author(s):  
B. Joseph ◽  
R. Torchio ◽  
C. Benndorf ◽  
T. Irifune ◽  
T. Shinmei ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Cell Volume ◽  
Electronic Transition ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Compelling Evidence ◽  
Induced Changes

A direct compelling evidence of an electronic transition associated with the isostructural unit-cell volume discontinuity in CeP under pressure is provided using Ce L3-XAS. A DAC with a combination of a mini and a partially perforated anvils made of nanodiamonds permitted us to track the pressure induced changes in the 4f state of Ce in CeP.

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