Experimental studies on a mutant gene (cl) in the Mexican axolotl which affects cell membrane formation in embryos from females

1973 ◽  
Vol 32 (1) ◽  
pp. 155-166 ◽  
Author(s):  
Carole R. Carroll ◽  
E.B. Van Deusen
Keyword(s):  
Cell Membrane ◽  
Experimental Studies ◽  
Mutant Gene ◽  
Mexican Axolotl ◽  
Membrane Formation

scholarly journals Molecular dynamics simulations and experimental studies reveal differential permeability of withaferin-A and withanone across the model cell membrane

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Renu Wadhwa ◽  
Neetu Singh Yadav ◽  
Shashank P. Katiyar ◽  
Tomoko Yaguchi ◽  
Chohee Lee ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Cell Membrane ◽  
Molecular Dynamics Simulations ◽  
Experimental Studies ◽  
Bilayer Membrane ◽  
Withaferin A ◽  
Head Group ◽  
Polar Head Group ◽  
Natural Drugs ◽  
Dynamics Simulations

AbstractPoor bioavailability due to the inability to cross the cell membrane is one of the major reasons for the failure of a drug in clinical trials. We have used molecular dynamics simulations to predict the membrane permeability of natural drugs—withanolides (withaferin-A and withanone) that have similar structures but remarkably differ in their cytotoxicity. We found that whereas withaferin-A, could proficiently transverse through the model membrane, withanone showed weak permeability. The free energy profiles for the interaction of withanolides with the model bilayer membrane revealed that whereas the polar head group of the membrane caused high resistance for the passage of withanone, the interior of the membrane behaves similarly for both withanolides. The solvation analysis further revealed that the high solvation of terminal O5 oxygen of withaferin-A was the major driving force for its high permeability; it interacted with the phosphate group of the membrane that led to its smooth passage across the bilayer. The computational predictions were tested by raising and recruiting unique antibodies that react to withaferin-A and withanone. The time-lapsed analyses of control and treated cells demonstrated higher permeation of withaferin-A as compared to withanone. The concurrence between the computation and experimental results thus re-emphasised the use of computational methods for predicting permeability and hence bioavailability of natural drug compounds in the drug development process.

scholarly journals Cation-chloride cotransporters, Na/K pump, and channels in cell water and ions regulation: in silico and experimental studies of the U937 cells under stopping the pump and during RVD

2021 ◽  
Author(s):  
Alexey A Vereninov ◽  
Valentina Yurinskaya
Keyword(s):  
Plasma Membrane ◽  
Cell Membrane ◽  
Real Time ◽  
Intracellular Signaling ◽  
Ion Homeostasis ◽  
Regulatory Volume Decrease ◽  
Experimental Studies ◽  
U937 Cells ◽  
Ionic Homeostasis ◽  
Monovalent Ions

Cation-coupled chloride cotransporters play a key role in generating the Cl− electrochemical gradient on the cell membrane which is important for regulation of many cellular processes. However, the cooperation of transporters and channels of the plasma membrane in holding the ionic homeostasis of the whole cell remains poorly characterized because of the lack of a suitable tool for its computation. Our software successfully predicted in real-time changes in the ion homeostasis of U937 cells after stopping the Na/K pump, but so far considered the model with only NC cotransporter. Here the model with all main types of cotransporters is used in computation of the rearrangements of ionic homeostasis due to stopping the pump and associated with the regulatory volume decrease (RVD) of cells swollen in hypoosmolar medium. The parameters obtained for the real U937 cells are used. Successful prediction of changes in ion homeostasis in real-time after stopping the pump using the model with all major cotransporters indicates that the model is reliable. Using this model for analysis RVD showed that there is a "physical" RVD, associated with the time-dependent changes in electrochemical ion gradients, but not with alteration of channels and transporters of the plasma membrane that should be considered in studies of truly active regulatory processes mediated by the intracellular signaling network. The developed software can be useful for calculation of the balance of the partial unidirectional fluxes of monovalent ions across the cell membrane of various cells under various conditions.

Experimental studies on a mutant gene (p) causing premature death of Ambystoma mexicanum embryos

Development ◽  
1977 ◽  
Vol 39 (1) ◽  
pp. 139-149
Author(s):  
Thomas M. Trottier ◽  
John B. Armstrong
Keyword(s):  
Muscle Development ◽  
Experimental Studies ◽  
Circulatory System ◽  
Premature Death ◽  
Mutant Gene ◽  
Ambystoma Mexicanum ◽  
Recessive Lethal ◽  
Homozygous Condition ◽  
General Defect ◽  
Superficial Tissue

The premature death (p) mutation is a recessive lethal, which, in the homozygous condition, gives rise to a complex of abnormalities. The mutant embryos develop only to stage 37, at which time disintegration of superficial tissue begins. Many of the abnormalities observed in sections of the stage-37 mutant embryo are related to its failure to establish a functioning circulatory system, or to the resulting edema and/or ascites that distend the abdomen and flanks. There are, however, abnormalities of heart, liver, gill and muscle development which cannot be attributed to lack of circulation and edema. All of these abnormalities can be indirectly related to the endoderm, particularly the anterior and dorsal endoderm. The findings, therefore, suggest that the mutation leads to a fairly general defect of the endoderm.

Cleavage in the chick embryo

Development ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 55-69
Author(s):  
Ruth Bellairs ◽  
F. W. Lorenz ◽  
Tania Dunlap
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chick Embryo ◽  
Cell Membrane ◽  
Cortical Region ◽  
Chick Embryos ◽  
Membrane Formation ◽  
Transmission Electron

Chick embryos ranging from the stage of first cleavage to that of about 700 cells were removed from the oviduct and examined by transmission electron microscopy. Beneath the cell membrane is a yolk-free cortical region containing microfilaments. Beneath this lies cytoplasm which contains yolk spheres which are graded in size, the dorsal ones being smaller than the ventral ones. The subgerminal periblast possesses a greater proportion of yolk to cytoplasm than do the cells proper, but it merges with the cytoplasm at the incomplete borders of the ‘open’ cells. Specialized accumulations of membranes lie in the marginal periblast, and it is suggested that they play a role in cell membrane formation.

Electroporation and recovery of cardiac cell membrane with rectangular voltage pulses

1992 ◽  
Vol 263 (4) ◽  
pp. H1128-H1136 ◽  
Author(s):  
O. Tovar ◽  
L. Tung
Keyword(s):  
Cell Membrane ◽  
Time Course ◽  
Low Voltage ◽  
Experimental Studies ◽  
Membrane Conductance ◽  
Cardiac Cells ◽  
Channel Blockers ◽  
Cardiac Cell ◽  
Patch Clamp Technique ◽  
Pipette Solution

Electroporation of the cardiac cell membrane may result from intense electric fields applied to cardiac muscle, associated for example with defibrillation and cardioversion. We analyzed the distribution of voltage levels sufficient to cause electroporation in enzymatically isolated frog cardiac cells, using the cell-attached patch-clamp technique with rectangular pulses similar to those used in experimental studies of cardiac defibrillation. Five-millisecond monophasic or ten-millisecond biphasic symmetric (1/1) and asymmetric (1/0.5) rectangular pulses of either polarity were applied to the cell membrane in 100-mV steps from 0.2 to 0.8 V. The membrane conductance was continuously monitored by a low-voltage pulse train. In a total of 77 cells, we observed a step increase in conductance, occurring in 21% of cells at a transmembrane potential of 0.3 V, 52% at 0.4 V, 14% at 0.5 V, and 13% at 0.6-0.8 V. Electroporation occurred with this voltage distribution regardless of pulse shape, polarity, or the presence of all of the following ionic channel blockers: tetrodotoxin, barium, tetraethylammonium, 4-aminopyridine, cadmium, nickel, and gadolinium. The time course of membrane recovery was highly variable. The maintenance of a high membrane conductance after the shock pulse was associated with irreversible cell contracture provided that Ca2+ was included in the patch-pipette solution. However, with biphasic asymmetric pulses, the conductance recovered very quickly (< or = 37 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

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