scholarly journals Low viscosity in the aqueous domain of cell cytoplasm measured by picosecond polarization microfluorimetry.

1991 ◽  
Vol 112 (4) ◽  
pp. 719-725 ◽  
Author(s):  
K Fushimi ◽  
A S Verkman
Keyword(s):  
Free Water ◽  
Fluid Phase ◽  
Rotational Correlation Time ◽  
Cell Cytoplasm ◽  
Intact Cells ◽  
Low Viscosity ◽  
3T3 Fibroblasts ◽  
Anisotropy Decay ◽  
Novel Method ◽  
Swiss 3T3 Fibroblasts

Information about the rheological characteristics of the aqueous cytoplasm can be provided by analysis of the rotational motion of small polar molecules introduced into the cell. To determine fluid-phase cytoplasmic viscosity in intact cells, a polarization microscope was constructed for measurement of picosecond anisotropy decay of fluorescent probes in the cell cytoplasm. We found that the rotational correlation time (tc) of the probes, 2,7-bis-(2-carboxyethyl)-5-(and-6-)carboxyfluorescein (BCECF), 6-carboxyfluorescein, and 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) provided a direct measure of fluid-phase cytoplasmic viscosity that was independent of probe binding. In quiescent Swiss 3T3 fibroblasts, tc values were 20-40% longer than those in water, indicating that the fluid-phase cytoplasm is only 1.2-1.4 times as viscous as water. The activation energy of fluid-phase cytoplasmic viscosity was 4 kcal/mol, which is similar to that of water. Fluid-phase cytoplasmic viscosity was altered by less than 10% upon addition of sucrose to decrease cell volume, cytochalasin B to disrupt cell cytoskeleton, and vasopressin to activate phospholipase C. Nucleoplasmic and peripheral cytoplasmic viscosities were not different. Our results establish a novel method to measure fluid-phase cytoplasmic viscosity, and indicate that fluid-phase cytoplasmic viscosity in fibroblasts is similar to that of free water.

Real-Time Measurement of Intracellular Reactive Oxygen Species Using Mito Tracker Orange (CMH2TMRos)

2001 ◽  
Vol 21 (3) ◽  
pp. 341-352 ◽  
Author(s):  
Soo-Mi Kweon ◽  
Hyun-Jung Kim ◽  
Zee-Won Lee ◽  
Soo-Jung Kim ◽  
Seung-IL Kim ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Real Time ◽  
Reduced Form ◽  
Oxygen Species ◽  
3T3 Fibroblasts ◽  
Real Time Measurement ◽  
Intracellular Ros ◽  
Novel Method ◽  
Swiss 3T3 Fibroblasts ◽  
Mitotracker Orange

We have investigated a novel method to monitor real changes of intracellular ROS by the use of CMH2TMRos (a reduced form of MitoTracker orange) in Swiss 3T3 fibroblasts. Arachidonic acid induced a rapid increase of CMTMRos fluorescence with a maximal elevation at 120–150 sec, which was determined by scanning every 10 sec with a confocal microscope. The fluorescence increase by arachidonic acid was completely inhibited by 2-MPG but not by catalase, indicating a major contribution of superoxide to the oxidation of CMH2TMRos. Incubation with glucose oxidase, exogenous H2O2, KO2 and lysophosphatidic acid also increased the CMTMRos fluorescence, which was blocked by 2-MPG. These results suggested that CMH2TMRos is a useful fluorophore for real-time monitoring of intracellular ROS and also indicated that CMH2TMRos detects primarily superoxide in cells even though the fluorophore can be oxidized by both superoxide and H2O2.

scholarly journals Synthesis and release of hyaluronic acid by Swiss 3T3 fibroblasts

1995 ◽  
Vol 309 (2) ◽  
pp. 649-656 ◽  
Author(s):  
J R Kitchen ◽  
R L Cysyk
Keyword(s):  
Hyaluronic Acid ◽  
Culture Medium ◽  
Culture Media ◽  
Cell Populations ◽  
Synthetase Activity ◽  
Intact Cells ◽  
3T3 Fibroblasts ◽  
Swiss 3T3 ◽  
Time Required ◽  
Swiss 3T3 Fibroblasts

Hyaluronic acid (HA) and its synthesis were studied in intact Swiss 3T3 mouse fibroblasts and isolated membranes. HA chains in culture medium, attached to cells and in isolated membranes, were determined to possess average M(r) values of 5.2 x 10(6), 1.8 x 10(6) and 0.14 x 10(6) respectively. Log cells were determined to possess 680,000 HA molecules/cell, and to release 120,000 HA chains/h. The time required for intact cells to synthesize and release a complete HA chain was approximately 4 h, with elongation proceeding at a rate of 57 dimers/min. The amount of cell-associated HA of various cell populations correlated strongly with their rate of HA release into culture media and with the HA synthetase activity determined for their membranes. Prevention of protein synthesis with cycloheximide decreased the rate of HA synthesis of log cells and HA synthetase activity of isolated membranes by 50% within 2-3 h. Because of the similarity between the biological lifetime of HA synthetase and the time required to synthesize a HA chain, we propose a model where each synthetase makes only one HA chain; after synthesis of a complete HA chain, HA synthetase activity is terminated as its HA chain is released from the cell.

scholarly journals Determinants of the translational mobility of a small solute in cell cytoplasm.

1993 ◽  
Vol 120 (1) ◽  
pp. 175-184 ◽  
Author(s):  
H P Kao ◽  
J R Abney ◽  
A S Verkman
Keyword(s):  
Diffusion Coefficient ◽  
Cell Volume ◽  
Diffusion Coefficients ◽  
Rotational Diffusion ◽  
Fluid Phase ◽  
Polarization Microscopy ◽  
Cell Cytoplasm ◽  
Translational Mobility ◽  
3T3 Fibroblasts ◽  
Small Solute

The purposes of this study were: (a) to measure the translational mobility of a small solute in cell cytoplasm; (b) to define quantitatively the factors that determine solute translation; and (c) to compare and contrast solute rotation and translation. A small fluorescent probe, 2,7-bis-(2-carboxyethyl)-5-(and 6-)-carboxyfluorescein (BCECF), was introduced into the cytoplasm of Swiss 3T3 fibroblasts. BCECF translation was measured by fluorescence recovery after photo-bleaching; rotation was measured by Fourier transform polarization microscopy. Diffusion coefficients relative to those in water (D/D0) were determined by comparing mobility in cytoplasm with mobility in standard solutions of known viscosity. At isosmotic cell volume, the relative diffusion coefficients for BCECF translation and rotation in cytoplasm were 0.27 +/- 0.01 (SEM, n = 24, 23 degrees C) and 0.78 +/- 0.03 (n = 4), respectively. As cell volume increased from 0.33 to 2 times isosmotic volume, the relative translational diffusion coefficient increased from 0.047 to 0.32, while the relative rotational diffusion coefficient remained constant. The factors determining BCECF translation were evaluated by comparing rotation and translation in cytoplasm, and in artificial solutions containing dextrans (mobile barriers) and agarose gels (immobile barriers). It was concluded that the hindrance of BCECF translation in cytoplasm could be quantitatively attributed to three independent factors: (a) fluid-phase cytoplasmic viscosity is 28% greater than the viscosity of water (factor 1 = 0.78); (b) 19% of BCECF is transiently bound to intracellular components of low mobility (factor 2 = 0.81); and most importantly, (c) translation of unbound BCECF is hindered 2.5-fold by collisions with cell solids comprising 13% of isosmotic cell volume (factor 3 = 0.40). The product of the 3 factors is 0.25 +/- 0.03, in good agreement with the measured D/D0 of 0.27 +/- 0.01. These results provide the first measurement of the translational mobility of a small solute in cell cytoplasm and define quantitatively the factors that slow solute translation.

scholarly journals ROCK and mDia1 antagonize in Rho-dependent Rac activation in Swiss 3T3 fibroblasts

2002 ◽  
Vol 157 (5) ◽  
pp. 819-830 ◽  
Author(s):  
Takahiro Tsuji ◽  
Toshimasa Ishizaki ◽  
Muneo Okamoto ◽  
Chiharu Higashida ◽  
Kazuhiro Kimura ◽  
...  
Keyword(s):  
Focal Adhesions ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Stress Fibers ◽  
Induced Membrane ◽  
3T3 Fibroblasts ◽  
C3 Exoenzyme ◽  
Swiss 3T3 ◽  
Swiss 3T3 Fibroblasts ◽  
Membrane Ruffle

The small GTPase Rho acts on two effectors, ROCK and mDia1, and induces stress fibers and focal adhesions. However, how ROCK and mDia1 individually regulate signals and dynamics of these structures remains unknown. We stimulated serum-starved Swiss 3T3 fibroblasts with LPA and compared the effects of C3 exoenzyme, a Rho inhibitor, with those of Y-27632, a ROCK inhibitor. Y-27632 treatment suppressed LPA-induced formation of stress fibers and focal adhesions as did C3 exoenzyme but induced membrane ruffles and focal complexes, which were absent in the C3 exoenzyme-treated cells. This phenotype was suppressed by expression of N17Rac. Consistently, the amount of GTP-Rac increased significantly by Y-27632 in LPA-stimulated cells. Biochemically, Y-27632 suppressed tyrosine phosphorylation of paxillin and focal adhesion kinase and not that of Cas. Inhibition of Cas phosphorylation with PP1 or expression of a dominant negative Cas mutant inhibited Y-27632–induced membrane ruffle formation. Moreover, Crk-II mutants lacking in binding to either phosphorylated Cas or DOCK180 suppressed the Y-27632–induced membrane ruffle formation. Finally, expression of a dominant negative mDia1 mutant also inhibited the membrane ruffle formation by Y-27632. Thus, these results have revealed the Rho-dependent Rac activation signaling that is mediated by mDia1 through Cas phosphorylation and antagonized by the action of ROCK.

cDNA-cloning, sequencing and expression in glucocorticoid-stimulated quiescent Swiss 3T3 fibroblasts of mouse lipocortin I

1989 ◽  
Vol 159 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Christine Philipps ◽  
Stefan Rose-John ◽  
Gabriele Rincke ◽  
Gerhard Fürstenberger ◽  
Friedrich Marks
Keyword(s):  
Cdna Cloning ◽  
3T3 Fibroblasts ◽  
Swiss 3T3 ◽  
Sequencing And Expression ◽  
Swiss 3T3 Fibroblasts
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