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  • 1
    Electronic Resource
    Electronic Resource
    Characterization of a novel fibroblast-like cell line from rainbow trout and responses to sublethal anoxia (2004)
    Oxford, UK; Malden , USA : Blackwell Publishing Ltd/Inc
    Journal of fish biology 64 (2004), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A novel fibroblast-like cell line RTHDF was established from hypodermal connective tissue of rainbow trout Oncorhynchus mykiss and telomerase activity was demonstrated early and late in cell line development. When RTHDF cells were exposed to bioenergetic stress, i.e. anoxia, activation of the stress activated member of the mitogen-activated protein kinase family, p38MAPK and induction of heat shock protein (Hsp70) were evident. The time-course of the p38MAPK activation and the induction of Hsp70 expression in RTHDF were studied in response to chemically induced anoxia. p38MAPK was activated rapidly, with maximal activity after 10 min of anoxia. Hsp70 was induced after 30 min of anoxia, followed by overnight recovery in growth medium at 21° C. Using the p38MAPK-specific inhibitor SB203580, the enhanced expression of Hsp70 occurred independently of p38MAPK activation in RTHDF. These data suggests that RTHDF can be useful in studying biochemical responses of teleost cells to environmental stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2004.0378.x
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  • 2
    Electronic Resource
    Electronic Resource
    Relation between cytoskeleton, hypo-osmotic treatment and volume regulation in Ehrlich ascites tumor cells (1993)
    Springer
    The journal of membrane biology 131 (1993), S. 55-66 
    Details
    ISSN: 1432-1424
    Keywords: volume regulation ; Ehrlich ascites tumor cells ; microfilament ; Ca2+ and Ca2+-ionophore A23187 ; quinine ; calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Pretreatment with cytochalasin B, which is known to disrupt microfilaments, significantly inhibits regulatory volume decrease (RVD) in Ehrlich ascites tumor cells, suggesting that an intact microfilament network is a prerequisite for a normal RVD response. Colchicine, which is known to disrupt microtubules, has no significant effect on RVD. Ehrlich cells have a cortical three-dimensional, orthogonal F-actin filament network which makes the cells look completely black in light microscopy following immunogold/silver staining using anti-actin antibodies. After addition of cytochalasin B, the stained cells get lighter with black dots localized to the plasma membrane and appearance of multiple knobby protrusions at cell periphery. Also, a significant decrease in the staining of the cells is seen after 15 min of RVD in hypotonic medium. This microfilament reorganization appears during RVD in the presence of external Ca2+ or Ca2+-ionophore A23187. It is, however, abolished in the absence of extracellular calcium, with or without prior depletion of intracellular Ca2+ stores. An effect of increased calcium influx might therefore be considered. The microfilament reorganization during RVD is abolished by the calmodulin antagonists pimozide and trifluoperazine, suggesting the involvement of calmodulin in the process. The microfilament reorganization is also prevented by addition of quinine. This quinine inhibition is overcome by addition of the K+ ionophore valinomycin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02258534
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  • 3
    Electronic Resource
    Electronic Resource
    The Na-K-2Cl cotransporter is in a permanently activated state in cytoplasts from Ehrlich ascites tumor cells (1994)
    Springer
    The journal of membrane biology 138 (1994), S. 229-239 
    Details
    ISSN: 1432-1424
    Keywords: Membrane vesicles ; Volume regulation ; Bumetanide ; Cytochalasin B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Brief incubation of Ehrlich ascites tumor cells with cytochalasin B causes the formation of blebs in the surface membrane. Gentle homogenization removes the blebs as intact cytoplasts which contain neither mitochondrian or nucleus, nor other cytoplasmic membranous organelles. The Na-K-2Cl cotransporter is present in the cytoplasts in a permanently activated state, whereas the Na-K-2Cl transport system in unperturbed intact cells is silent. Pretreatment of intact cells with cytochalasin B for l min stimulates the bumetanide-inhibitable K+ influx ∼fivefold. The influx into purified cytoplasts when expressed per g protein is three- to fourfold higher than the influx into cytochalasin B-treated intact cells. Thus, the membrane vesicles are enriched with the cotransporter, and the cotransporter is present in an activated state. The K influx into cytoplasts is inhibited about 40% by Na-free, Cl-free or bumetanide-containing media and to a similar extent by Fab fragments prepared from antiserum against purified proteins of the cotransporter. The K I for bumetanide was 0.19±0.06 μm for the cytoplasts as compared to 0.67±0.11 μm for the intact cells. SDS gel electrophoresis of membrane proteins from the cytoplast membranes compared to the membranes of intact cells shows a reduced number of bands and a majority of bands showing reduced staining, whereas a few bands are stained more intensely. Particularly notable is a band at ∼80 kD, which is similar to the molecular weight previously reported for the main membrane protein isolated from intact cells using a bumetanide-Sepharose affinity column. An immunoblot of the cytoplast preparation using antibodies against the purified bumetanide binding proteins showed strong immunodetection of the ∼80 kD protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232795
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  • 4
    Electronic Resource
    Electronic Resource
    Cell swelling activates separate taurine and chloride channels in Ehrlich mouse ascites tumor cells (1994)
    Springer
    The journal of membrane biology 142 (1994), S. 289-298 
    Details
    ISSN: 1432-1424
    Keywords: Taurine ; Anion channel ; Indacrinone ; Arachidonic acid ; Oleic acid ; DIDS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The taurine efflux from Ehrlich ascites tumor cells is stimulated by hypotonic cell swelling. The swelling-activated taurine efflux is unaffected by substitution of gluconate for extracellular Cl− but inhibited by addition of MK196 (anion channel blocker) and 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS; anion channel and anion exchange blocker) and by depolarization of the cell membrane. This is taken to indicate that taurine does not leave the osmotically swollen Ehrlich cells in exchange for extracellular Cl−, i.e., via the anion exchanger but via a MK196- and DIDS-sensitive channel that is potential dependent. An additional stimulation of the swelling-activated taurine efflux is seen after addition of arachidonic acid and oleic acid. Cell swelling also activates a “Mini Cl− channel.” The Cl− efflux via this Cl− channel, in contrast to the swelling-activated taurine efflux, is unaffected by DIDS and inhibited by arachidonic acid and oleic acid. It is suggested that the swelling-activated “Mini Cl− channel” and the swelling-activated taurine channel in the Ehrlich cell represent two distinct types of channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233436
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  • 5
    Electronic Resource
    Electronic Resource
    Cell swelling activates K+ and Cl− channels as well as nonselective, stretch-activated cation channels in ehrlich ascites tumor cells (1992)
    Springer
    The journal of membrane biology 129 (1992), S. 13-36 
    Details
    ISSN: 1432-1424
    Keywords: K+ channel ; Cl− channel ; patch clamp ; nonselective cation channel ; stretch-activated channel ; volume regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Cell-attached patch-clamp recordings from Ehrlich ascites tumor cells reveal nonselective cation channels which are activated by mechanical deformation of the membrane. These channels are seen when suction is applied to the patch pipette or after osmotic cell swelling. The channel activation does not occur instantaneously but within a time delay of 1/2 to 1 min. The channel is permeable to Ba2+ and hence presumably to Ca2+. It seems likely that the function of the nonselective, stretch-activated channels is correlated with their inferred Ca2+ permeability, as part of the volume-activated signal system. In isolated insideout patches a Ca2+-dependent, inwardly rectifying K+ channel is demonstrated. The single-channel conductance recorded with symmetrical 150 mm K+ solutions is for inward current estimated at 40 pS and for outward current at 15 pS. Activation of the K+ channel takes place after an increase in Ca2+ from 10−7 to 10−6 m which is in the physiological range. Patch-clamp studies in cellattached mode show K+ channels with spontaneous activity and with characteristics similar to those of the K+ channel seen in excised patches. The single-channel conductance for outward current at 5 mm external K+ is estimated at about 7 pS. A K+ channel with similar properties can be activated in the cellattached mode by addition of Ca2+ plus ionophore A23187. The channel is also activated by cell swelling, within 1 min following hypotonic exposure. No evidence was found of channel activation by membrane stretch (suction). The time-averaged number of open K+ channels during regulatory volume decrease (RVD) can be estimated at 40 per cell. The number of open K+ channels following addition of Ca2+ plus ionophore A23187 was estimated at 250 per cell. Concurrent activation in cell-attached patches of stretch-activated, nonselective cation channels and K+ channels in the presence of 3 mm Ca2+ in the pipette suggests a close spatial relationship between the two channels. In excised inside-out patches (with NMDG chloride on both sides) a small 5-pS chloride channel with low spontaneous activity is observed. The channel activity was not dependent on Ca2+ and could not be activated by membrane stretch (suction). In cell-attached mode singlechannel currents with characteristics similar to the channels seen in isolated patches are seen. In contrast to the channels seen in isolated patches, the channels in the cell-attached mode could be activated by addition of Ca2+ plus ionophore A23187. The channel is also activated by hypotonic exposure with a single-channel conductance at 7 pS (or less) and with a time delay at about 1 min. The number of open channels during RVD is estimated at 80 per cell. Two other types of Cl− channels were regularly recorded in excised inside-out patches: a voltage-activated 400-pS channel and a 34-pS Cl− channel which show properties similar to the Cl− channel in the apical membrane in human airway epithelial cells. There is no evidence for a role in RVD for either of these two channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232052
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  • 6
    Electronic Resource
    Electronic Resource
    Volume regulation in human fibroblasts: role of Ca2+ and 5-lipoxygenase products in the activation of the Cl− efflux (1993)
    Springer
    The journal of membrane biology 136 (1993), S. 55-62 
    Details
    ISSN: 1432-1424
    Keywords: Regulatory volume decrease ; Volume regulation ; Cl− channel ; 5-Lipoxygenase ; Leukotriene-D4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Trypsinized human skin fibroblasts in suspension perform regulatory volume decrease (RVD) after cell swelling in hypotonic medium. During RVD, 36Cl− efflux is dramatically increased and the cell membrane is depolarized, indicating the activation of Cl− channels. This activation of Cl− channels depends on extracellular as well as on intracellular Ca2+. The swelling-induced Cl− efflux and the RVD response are inhibited by the 5-lipoxygenase inhibitor ETH 615-139. Finally, following hypotonic treatment, cellular pH decreases. The pH decrease does not involve the Cl−/HCO 3 − exchange because it is independent of the external Cl− concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241489
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  • 7
    Electronic Resource
    Electronic Resource
    pHi regulation in Ehrlich mouse ascites tumor cells: Role of sodium-dependent and sodium-independent chloride-bicarbonate exchange (1994)
    Springer
    The journal of membrane biology 138 (1994), S. 121-132 
    Details
    ISSN: 1432-1424
    Keywords: pH regulation ; pH i maintenance ; Na+/H+ exchange ; Na+-dependent Cl−/HCO3 − exchange ; Na+-independent Cl−/HCO3 − exchange ; 36Cl− Efflux
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract pH i recovery in acid-loaded Ehrlich ascites tumor cells and pH i maintenance at steady-state were studied using the fluorescent probe BCECF. Both in nominally HCO 3 − -free media and at 25 mm HCO 3 − , the measured pH i (7.26 and 7.82, respectively) was significantly more alkaline than the pH i . value calculated assuming the transmembrane HCO 3 − gradient to be equal to the Cl− gradient. Thus, pH i in these cells is not determined by the Cl− gradient and by Cl−/HCO 3 − exchange. pH i recovery following acid loading by propionate exposure, NH 4 + withdrawal, or CO2 exposure is mediated by amiloride-sensitive Na+/H+ exchange in HCO3 − free media, and in the presence of HCO 3 − (25 mm) by DIDS-sensitive, Na+-dependent Cl−/HCO 3 − exchange. A significant residual pH i recovery in the presence of both amiloride and DIDS suggests an additional role for a primary active H+ pump in pH i regulation. pH i maintenance at steady-state involves both Na+/H+ exchange and Na+-dependent Cl−/HCO 3 − exchange. Acute removal of external Cl− induces a DIDS-sensitive, Na+-dependent alkalinization, taken to represent HCO 3 − influx in exchange for cellular Cl−. Measurements of 36Cl− efflux into Cl−-free gluconate media with and without Na+ and/or HCO 3 − (10 mm) directly demonstrate a DIDS-sensitive, Na+ dependent Cl−/HCO 3 − exchange operating at slightly acidic pH i (pHo 6.8), and a DIDS-sensitive, Na+-independent Cl−/HCO 3 − exchange operating at alkaline pH i (pH o 8.2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232640
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  • 8
    Electronic Resource
    Electronic Resource
    Purification of proteins of the Na/Cl cotransporter from membranes of Ehrlich ascites cells using a bumetanide-sepharose affinity column (1988)
    Springer
    The journal of membrane biology 103 (1988), S. 135-147 
    Details
    ISSN: 1432-1424
    Keywords: Na/Cl cotransport ; azidobumetanide ; bumetanide-Sepharose affinity column ; Ehrlich ascites cells ; purified cotransporter proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Bumetanide-binding proteins were isolated from membranes of Ehrlich ascites tumor cells by affinity chromatography. An affinity column was constructed with the active moiety of bumetanide as a ligand using 4′-azidobumetanide, a photoactive analogue which inhibits Na/Cl cotransport in Ehrlich cells with high specificity. Covalent binding of the 4′-azidobumetanide with Sepharose was promoted by photolysis. Membranes isolated from Ehrlich cells were solubilized withn-octylglucoside. Solubilized proteins retarded by the affinity column were readily eluted by bumetanide. In reducing gels the major proteins eluted by bumetanide were ∼76 kDa and 38–39 kDa. There were also two proteins of 32 to 35 kDa eluted in lesser amounts. No proteins retarded by the affinity column were eluted with extensive washing without bumetanide. Furthermore, bumetanide eluted no proteins from a „control” column lacking the specific ligand. Upon rechromatography with bumetanide in solution, bumetanide-eluted proteins were not retarded, but their purity was increased by the retardation of contaminating proteins. Bumetanide-binding protein purified in this manner were characterized further by electrophoresis in nonreducing, nondenaturing gels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870944
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