scholarly journals ACTION OF CYTOCHALASIN D ON CELLS OF ESTABLISHED LINES

1974 ◽  
Vol 61 (2) ◽  
pp. 481-500 ◽  
Author(s):  
Armand F. Miranda ◽  
Gabriel C. Godman ◽  
Arline D. Deitch ◽  
Stuart W. Tanenbaum
Keyword(s):  
Contractile Response ◽  
Sugar Transport ◽  
Cytochalasin D ◽  
Response Patterns ◽  
Early Effect ◽  
Mdbk Cells ◽  
Hexose Uptake ◽  
Cytoplasmic Processes ◽  
Indirect Action ◽  
Structural Disruption

HeLa, Vero, L, HEp2, and MDBK cells respond immediately to 0.2–0.5 µg/ml cytochalasin D (CD) with sustained contraction (contracture), loss of microvilli, expression of endoplasmic contents (zeiosis), nuclear protrusion, and extension of cytoplasmic processes. The development of these changes is depicted, and the dose-response patterns in these cell lines are described. MDBK is generally most resistant and HeLa most sensitive to these effects of CD. Cells in G1 are most sensitive to CD; responsiveness decreases progressively during early S and is least in mid S through G2. CD inhibits transport of [14C]deoxyglucose in HeLa by about 45% but has no significant effect on hexose uptake in Vero and MDBK; sugar transport is thus apparently unrelated to any morphologic effect of CD. Although spreading and attachment are impeded, CD does not decrease and may even enhance the adhesiveness of established monolayers. Contraction appears to be a primary early effect of CD, upon which other visible changes follow. It is prevented by some inhibitors of energy metabolism (deoxyglucose and dinitrophenol) and does not occur in glycerinated models without ATP. The possible bases of the contractile response to CD are discussed. Although direct or indirect action of CD on some microfilaments may occur, a generalized structural disruption of contractile filaments by CD is considered unlikely.

Amino acid and hexose transport by cultured crypt cells from rat small intestine

1980 ◽  
Vol 239 (5) ◽  
pp. C190-C196 ◽  
Author(s):  
K. Inui ◽  
A. Quaroni ◽  
L. G. Tillotson ◽  
K. J. Isselbacher
Keyword(s):  
Amino Acid ◽  
Sugar Transport ◽  
Epithelial Cell Line ◽  
Acid Uptake ◽  
Substrate Uptake ◽  
Hexose Transport ◽  
Intestinal Crypt ◽  
Morphological Criteria ◽  
Hexose Uptake ◽  
Crypt Cells

The characteristics of amino acid and sugar transport in intestinal crypt epithelial cells have been examined by measuring substrate uptake in an established epithelial cell line. These cells (IEC-6 cells) have been characterized as derived from rat small intestinal crypt cells on the basis of morphological criteria (J. Cell. Biol. 80: 248-265, 1979). Amino acid transport appeared to be mediated by both Na+-dependent and Na+-independent systems. Hexose uptake was stereospecific and Na+ independent, and was markedly inhibited by phloretin and cytochalasin B. Since glucocorticoids are known to have profound effects on maturation of the intestinal epithelium in vivo, their effects on transport properties of the cultured crypt cells were studied. Hydrocortisone, while completely inhibiting cell growth, increased the initial uptake rates of various hexoses, while having little or nor effect on the initial rate of amino acid uptake. The increased hexose uptake appeared to be due to a change in Vmax rather than Km. Appearance of the Na+-dependent hexose transport system, which is present in differentiated enterocytes, was not elicited by in vitro treatment with glucocortcoids.

Fading Memory Formulation for Active Stress Fibre Contractility

2010 ◽  
Author(s):  
Patrick McGarry ◽  
Robert M. McMeeking ◽  
Vikram S. Deshpande
Keyword(s):  
Experimental Work ◽  
Contractile Response ◽  
Morphological Changes ◽  
Cytochalasin D ◽  
In Vitro Studies ◽  
Fading Memory ◽  
Active Stress ◽  
Cyclic Stretching ◽  
Stress Fibre

Cytoskeletal alignment and morphological changes in cells under conditions of cyclic stretching have been reported in several in-vitro studies. Of particular interest is the experimental work of Wille et al. [1] in which the contractile response of fibroblast stress fibres was isolated and quantified by testing both untreated cells and cells treated with Cytochalasin-D.

Saturable and nonsaturable hexose uptake in cultured human skin fibroblasts

1978 ◽  
Vol 56 (2) ◽  
pp. 80-88 ◽  
Author(s):  
Ralph J. Germinario ◽  
Maureen Oliveira ◽  
Hyman Leung
Keyword(s):  
Human Skin ◽  
Cytochalasin B ◽  
Competitive Inhibition ◽  
Sugar Transport ◽  
Skin Fibroblasts ◽  
Sugar Uptake ◽  
Human Skin Fibroblasts ◽  
Rate Limiting Step ◽  
Hexose Uptake ◽  
Rate Limiting

The saturable transport of 2-deoxy-D-glucose across the cell membrane of cultured human skin fibroblasts was measured in sparse and confluent cultures. The contribution of nonsaturable sugar uptake to total sugar uptake was monitored by determining L-glucose uptake. The uptake of 2-deoxy-D-glucose was studied as a function of time and substrate concentration. Greater than 70% of transported 2-deoxy-D-glucose was phosphorylated after incubation for 2 min or less at all substrate concentrations employed (0.1 to 3.0 mM), and phosphorylation paralleled sugar uptake at these time intervals. Experiments with cytochalasin B demonstrated that an inhibition of transport was always paralleled by an equal inhibition of sugar phosphorylation.The kinetic constants for the uptake and phosphorylation of 2-deoxy-D-glucose and the inhibition of transport by competing sugars and cytochalasin B were calculated from Line-weaver-Burk plots. The Km and Vmax for saturable sugar uptake were calculated for sparse and confluent cultures after subtracting the contribution of nonsaturable sugar uptake. The resulting Km values for sugar uptake in the sparse and confluent cultures were 1.21 ± 0.04 and 0.88 ± 0.2 mM respectively. The corresponding Vmax values were 15.5 ± 1 nmol/mg protein∙min−1 for the sparse cultures and 10.1 ± 1 nmol/mg protein∙min−1 for the confluent cultures. In both sparse and confluent cultures, the Ki values for the competitive inhibition of sugar transport by D-glucose and 3-O-methyl-D-glucose were 0.8 and 2.7 mM respectively; the Ki value for the noncompetitive inhibition of sugar transport by cytochalasin B was 0.5 μM. The Km values for sugar phosphorylation by cell-free homogenates of sparse and confluent cultures were 0.57 ± 0.1 and 0.6 ± 0.1 mM respectively, while their respective Vmax values were 160 ± 53 and 139 ± 43 nmol/mg protein∙min−1.The data are in agreement with the concept that in cultured human skin fibroblasts sugar transport is the rate-limiting step in 2-deoxy-D-glucose metabolism and that phosphorylation is distinct from transport.

scholarly journals Aspergillus niger mstA encodes a high-affinity sugar/H+ symporter which is regulated in response to extracellular pH

2004 ◽  
Vol 379 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Patricia A. vanKUYK ◽  
Jasper A. DIDERICH ◽  
Andrew P. MacCABE ◽  
Oscar HERERRO ◽  
George J. G. RUIJTER ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Ph Regulation ◽  
Functional Characterization ◽  
Carbon Sources ◽  
Sugar Transport ◽  
Major Facilitator Superfamily ◽  
Northern Analysis ◽  
High Affinity ◽  
Hexose Uptake ◽  
Major Facilitator

A sugar-transporter-encoding gene, mstA, which is a member of the major facilitator superfamily, has been cloned from a genomic DNA library of the filamentous fungus Aspergillus niger. To enable the functional characterization of MSTA, a full-length cDNA was expressed in a Saccharomyces cerevisiae strain deficient in hexose uptake. Uptake experiments using 14C-labelled monosaccharides demonstrated that although able to transport d-fructose (Km, 4.5±1.0 mM), d-xylose (Km, 0.3±0.1 mM) and d-mannose (Km, 60±20 µM), MSTA has a preference for d-glucose (Km, 25±10 µM). pH changes associated with sugar transport indicate that MSTA catalyses monosaccharide/H+ symport. Expression of mstA in response to carbon starvation and upon transfer to poor carbon sources is consistent with a role for MSTA as a high-affinity transporter for d-glucose, d-mannose and d-xylose. Northern analysis has shown that mstA is subject to CreA-mediated carbon catabolite repression and pH regulation mediated by PacC. A. niger strains in which the mstA gene had been disrupted are phenotypically identical with isogenic reference strains when grown on 0.1–60 mM d-glucose, d-mannose, d-fructose or d-xylose. This indicates that A. niger possesses other transporters capable of compensating for the absence of MSTA.

Modeling the Active Contractility of Cells Under Dynamic Loading

2009 ◽  
Author(s):  
Patrick McGarry ◽  
Anthony G. Evans ◽  
Robert M. McMeeking ◽  
Vikram S. Deshpande
Keyword(s):  
Dynamic Loading ◽  
Experimental Work ◽  
Contractile Response ◽  
Morphological Changes ◽  
Cytochalasin D ◽  
In Vitro Studies ◽  
Cyclic Stretching ◽  
In Cells

Cytoskeletal alignment and morphological changes in cells under conditions of cyclic stretching have been reported in several in-vitro studies. Of particular interest is the experimental work of Wille et al. [1] in which the contractile response of fibroblasts was isolated and quantified by testing both untreated cells and cells treated with Cytochalasin-D.

scholarly journals S354 Using FLIP Panometry to Characterize Contractile Response Patterns in Patients With Eosinophilic Esophagitis

2021 ◽  
Vol 116 (1) ◽  
pp. S153-S153
Author(s):  
Christina Shehata ◽  
Dustin Carlson ◽  
NIrmala Gonsalves ◽  
Ikuo Hirano ◽  
Peter J. Kahrilas ◽  
...  
Keyword(s):  
Eosinophilic Esophagitis ◽  
Contractile Response ◽  
Response Patterns

Regulation of Na+-dependent sugar transport in intestinal epithelial cells by exogenous ATP

1980 ◽  
Vol 238 (5) ◽  
pp. C177-C183 ◽  
Author(s):  
G. Kimmich ◽  
J. Randles
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Sugar Transport ◽  
Late Effect ◽  
Nucleoside Triphosphate ◽  
Intestinal Epithelial ◽  
Early Effect ◽  
Adenine Ring ◽  
Transport Inhibition ◽  
Gradient Enhancement

Exogenous ATP (1 mM) exerts a dramatic biphasic effect on the accumulation of 100 micro M 3-O-methylglucose by isolated intestinal epithelial cells. The initial effect ensues approximately 15 s after exposure and inhibits 80% of the undirectional sugar influx. Cellular phosphatases totally degrade the added ATP within a period of 20 min leading to a reactivation of transport capability. The cells exposed to ATP ultimately establish a concentration gradient of sugar about twice that observed for control cells. Pyrophosphate (10 mM) delays the degradation of added ATP and prolongs the interval of transport inhibition. The late effect of gradient enhancement is still observed. No other nucleoside triphosphate induces the early inhibition of transport, but ADP is approximately two-thirds as effective as ATP. AMP and other molecules containing the adenine ring system can cause the late effect of gradient enhancement without causing an early transport inhibition. Because rotenone-treated ATP-depleted cells also show an ATP-induced inhibition of sugar influx, it seems likely that the early effect represents a direct modification of carrier capability rather than an effect mediated via an alteration of cellular energetics.

scholarly journals Action of cytochalasin D on cells of established lines. III. Zeiosis and movements at the cell surface.

1975 ◽  
Vol 64 (3) ◽  
pp. 644-667 ◽  
Author(s):  
G C Godman ◽  
A F Miranda ◽  
A D Deitch ◽  
S W Tanenbaum
Keyword(s):  
Cell Surface ◽  
Small Groups ◽  
Cellular Response ◽  
Contractile Response ◽  
Cytochalasin D ◽  
Main Body ◽  
Cell Surfaces ◽  
Temperature Dependent ◽  
Large Aggregate ◽  
Lower Temperature

The projection of knobby protuberances at the cell surface (zeiosis) is a general cellular response to cytochalasin D (CD), resulting from herniation of endoplasm through undefended places of the cortex during cell contractions and displacement of microfilaments induced by CD. Zeiosis is prevented by agents that interfere with the contractile response to CD, such as inhibitors of energy metabolism or cyclic AMP. The developed protrusions, which remain relatively stable in the presence of CD, contain chiefly mono- or subribosomes, and occasionally other organelles normally resident in endoplasm; compact microfilament felt occupies their bases and extends into their proximal stalks. Protein synthesis in the knobs is less than half of that in the polyribosome-containing endoplasm residual in the main body of the cell. Knobs first protrude singly near the margin of the contracting cells and rapidly cluster into small groups in the periphery even at lower temperature. The clusters then migrate centripetally and coalesce into a large aggregate near the apex of the immobilized and retracted cell: this movement is energy- and temperature-dependent. Aggregation is more prominent and stable in cell lines of epithelial derivation than in fibroblastic or other lines in which nuclear extrusion occurs more readily. The latter is regarded as a special manifestation of zeiosis. Macromarkers, such as latex spherules, migrate like the zeiotic knobs on the cell surfaces in the presence of CD. The aggregated knobs, although persistent for days in the presence of CD, are rapidly recessed after withdrawal of the agent as ruffling is resumed and the cells spread. These movements are discussed in terms of current concepts of mobility of the cell membrane.

Hexose uptake by developing cotyledons of Vicia faba: physiological evidence for transporters of differing affinities and specificities

2005 ◽  
Vol 32 (11) ◽  
pp. 987 ◽  
Author(s):  
Gregory N. Harrington ◽  
Katherine E. Dibley ◽  
Raymond J. Ritchie ◽  
Christina E. Offler ◽  
John W. Patrick
Keyword(s):  
Vicia Faba ◽  
Plasma Membranes ◽  
Sugar Transport ◽  
Transfer Cell ◽  
Transport Mechanisms ◽  
Cell Complexes ◽  
Stage Of Development ◽  
Storage Parenchyma ◽  
Hexose Uptake ◽  
And Storage

Cotyledons of broad bean (Vicia faba L.) develop in an apoplasmic environment that shifts in composition from one dominated by hexoses to one dominated by sucrose. During the latter phase of development, sucrose / H+ symporter activity and expression is restricted to cotyledon epidermal transfer cell complexes that support sucrose fluxes that are 8.5-fold higher than those exhibited by the storage parenchyma. In contrast, the flux difference between these cotyledon tissues is only 1.7-fold for hexoses. Glucose and fructose uptake was shown to be sensitive to PCMBS and phloridzin, both of which slow H+-sugar transport. A low Km (or high affinity transporter, HAT) mechanism transports glucose and glucose-analogues exclusively. No HAT system for fructose could be found. A high Km (low affinity transporter, LAT) mechanism transports a broader range of hexoses, including glucose and fructose. Consistent with glucose and fructose transport being H+-coupled, their uptake was inhibited by dissipating the proton motive force (pmf) by treating cotyledons with carbonyl cyanide m-chlorophenol hydrazone, propionic acid or tetraphenylphosphonium ion. Erythrosin B inhibited hexose uptake, indicating a role for the P-type H+-ATPase in establishing the pmf. It is concluded that H+-coupled glucose and fructose transport mechanisms occur at plasma membranes of dermal transfer cell complexes and storage parenchyma cells. These transport mechanisms are active during pre- and storage phases of cotyledon development. However, hexose symport only makes a quantitative contribution to cotyledon biomass gain during the pre-storage stage of development.

Neuron-glia relationship during the early postembryonic development of the nervous system in some oligochaetes

1978 ◽  
Vol 36 (2) ◽  
pp. 600-601
Author(s):  
Wiktor Djaczenko ◽  
Carmen Calenda Cimmino
Keyword(s):  
Nervous System ◽  
Glial Cells ◽  
Early Period ◽  
Postembryonic Development ◽  
Ruthenium Red ◽  
The Body ◽  
Tubifex Tubifex ◽  
Growth Stages ◽  
Cell Processes ◽  
Cytoplasmic Processes

The simplicity of the developing nervous system of oligochaetes makes of it an excellent model for the study of the relationships between glia and neurons. In the present communication we describe the relationships between glia and neurons in the early periods of post-embryonic development in some species of oligochaetes.Tubifex tubifex (Mull. ) and Octolasium complanatum (Dugès) specimens starting from 0. 3 mm of body length were collected from laboratory cultures divided into three groups each group fixed separately by one of the following methods: (a) 4% glutaraldehyde and 1% acrolein fixation followed by osmium tetroxide, (b) TAPO technique, (c) ruthenium red method.Our observations concern the early period of the postembryonic development of the nervous system in oligochaetes. During this period neurons occupy fixed positions in the body the only observable change being the increase in volume of their perikaryons. Perikaryons of glial cells were located at some distance from neurons. Long cytoplasmic processes of glial cells tended to approach the neurons. The superimposed contours of glial cell processes designed from electron micrographs, taken at the same magnification, typical for five successive growth stages of the nervous system of Octolasium complanatum are shown in Fig. 1. Neuron is designed symbolically to facilitate the understanding of the kinetics of the growth process.

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