scholarly journals Localization of intracellular proteins at acetylcholine receptor clusters induced by electric fields in Xenopus muscle cells

1989 ◽  
Vol 94 (1) ◽  
pp. 73-83
Author(s):  
M.W. Rochlin ◽  
H.B. Peng
Keyword(s):  
Electric Field ◽  
Acetylcholine Receptor ◽  
Electric Fields ◽  
Matrix Material ◽  
Muscle Cells ◽  
Ultrastructural Level ◽  
Anchoring Proteins ◽  
Intracellular Proteins ◽  
Receptor Clusters ◽  
Electric Field Treatment

Electric fields cause acetylcholine receptor (AChR) patches to form on the cathodal sides of cultured muscle cells. These patches are stable for several hours following cessation of an electric field treatment, indicating that the receptors are anchored to the cluster sites. Furthermore, at the ultrastructural level, AChR patches induced by electric fields are marked by an accumulation of extracellular matrix material and a sarcolemmal density. Thus, these AChR patches are similar to those induced by other stimuli, including nerve, polycation-coated beads, and the tissue culture substratum. Proteins that may be involved in anchoring AChRs have been colocalized with AChR patches induced by the latter three stimuli, but not at AChR patches induced by electric fields. In this study, we demonstrate that three putative anchoring proteins, 43K (K = 10(3) Mr) protein, 58K protein and talin, are associated with field-induced AChR patches. We also show that these proteins persist at field-induced AChR patches following removal of the field, indicating that they are stabilized at the AChR patch. Our data are consistent with the possibility that these proteins contribute to the stabilization of AChRs at patches induced by the electric field. Since 43K, 58K and talin are intracellular proteins, and therefore could not undergo field-induced lateral electrophoresis, our observations support the notion that the electric field triggers the formation of an AChR-stabilizing specialization.

scholarly journals Membrane-related specializations associated with acetylcholine receptor aggregates induced by electric fields.

1985 ◽  
Vol 100 (1) ◽  
pp. 235-244 ◽  
Author(s):  
P W Luther ◽  
H B Peng
Keyword(s):  
Acetylcholine Receptor ◽  
Electric Fields ◽  
Basal Lamina ◽  
Field Exposure ◽  
Thin Sections ◽  
Fluorescence Image ◽  
Before And After ◽  
Dc Electric Field ◽  
Receptor Clusters ◽  
Alpha Bungarotoxin

The localization of membrane-associated specializations (basal lamina and cytoplasmic density) at sites of acetylcholine receptor (AChR) aggregation is consistent with an involvement of these structures in receptor stabilization. We investigated the occurrence of these specializations in association with AChR aggregates that develop at the cathode-facing edge of Xenopus muscle cells during exposure to a DC electric field. The cultures were labeled with a fluorescent conjugate of alpha-bungarotoxin and the receptor distribution on selected cells was determined before and after exposure to the field. In thin sections taken from the same cells, the cathode-facing edge was characterized by plaques of basal lamina and cytoplasmic density co-extensive with sarcolemma of increased density. In sections cut in a plane similar to the fluorescence image, it was possible to demonstrate that the specializations were concentrated at areas of field-induced AChR aggregation, and at receptor clusters existing on control cells. This finding further indicates that these structures participate in AChR stabilization, and that the mechanisms involved in AChR aggregation that result from field exposure and nerve contact may be similar.

Pulsed Electric Fields Versus Thermal Treatment: Equivalent Processes To Obtain Equally Acceptable Citrus Juices

2006 ◽  
Vol 69 (8) ◽  
pp. 2016-2018 ◽  
Author(s):  
E. SENTANDREU ◽  
L. CARBONELL ◽  
D. RODRIGO ◽  
J. V. CARBONELL
Keyword(s):  
Thermal Treatment ◽  
Electric Field ◽  
Electric Fields ◽  
Pulsed Electric Fields ◽  
Pectin Methylesterase ◽  
Pulsed Electric Field ◽  
Citrus Juices ◽  
Pulsed Electric Field Treatment ◽  
Electric Field Treatment

Pulsed electric field treatment has been claimed to produce more acceptable chilled citrus juices than those obtained by conventional thermal treatment. The pectin methylesterase activity and the acceptability of nine juices obtained from Clementine mandarins, Valencia oranges, and Ortanique fruits (hybrid of mandarin and orange), untreated, pasteurized (85°C for 10 s), and treated by pulsed electric fields (25 kV/cm for 330 μs), were evaluated. The treatments, selected to reach a similar level of pectin methylesterase inactivation, produced juices that did not differ in acceptability from each other for the three varieties and in all cases were less acceptable than the untreated juice.

scholarly journals Development of Acetylcholine Receptor Clusters on Cultured Muscle Cells

1973 ◽  
Vol 70 (1) ◽  
pp. 270-274 ◽  
Author(s):  
A. J. Sytkowski ◽  
Z. Vogel ◽  
M. W. Nirenberg
Keyword(s):  
Acetylcholine Receptor ◽  
Muscle Cells ◽  
Receptor Clusters

scholarly journals Use of pulsed electric fields to induce breakage of glandular trichome cells in leaves of fresh patchouli (Pogostemon cablin Benth.): Specific energy input consumption

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Sukardi Sukardi ◽  
Sudjito Soeparman ◽  
Bambang Dwi Argo ◽  
Yudy Surya Irawan
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Specific Energy ◽  
Energy Input ◽  
Glandular Trichome ◽  
Specific Energy Input ◽  
Variable Electric Field ◽  
Pogostemon Cablin ◽  
Cell Changes ◽  
Electric Field Treatment

Research has been performed using a pulsed electric field (PEF) to damage plant cells to obtain bioactive compounds before extraction. However, research into the use of PEF to break down the glandular trichome (GT) cells of patchouli for essential oil extraction is still limited. The purpose of this study was to determine the specific energy input needed to break patchouli leaf GT cells by PEF treatment. Patchouli leaves were harvested at 7 months of age, then treated with PEF. GT cell changes were analyzed using scanning electron microscopy. The results show that treatment with variable frequencies caused GT cell wrinkling and treatments with a variable electric field caused GT cell rupture. Electric field treatment at E=133.33 V/cm and a PEF exposure time of 2 seconds or E=116.66 V/cm and 3 seconds of PEF exposure resulted in consistent rupture of GT cells. Energy consumption of 0.049 kJ/cm3 promoted GT cell wall shrinkage and consumption of 0.59 kJ/cm3 broke GT cell walls.

scholarly journals Freeze-fracture and electrophysiological studies of newly developed acetylcholine receptors in Xenopus embryonic muscle cells.

1984 ◽  
Vol 98 (6) ◽  
pp. 2160-2173 ◽  
Author(s):  
P C Bridgman ◽  
S Nakajima ◽  
A S Greenberg ◽  
Y Nakajima
Keyword(s):  
Size Distribution ◽  
Acetylcholine Receptor ◽  
Acetylcholine Receptors ◽  
Freeze Fracture ◽  
Muscle Cells ◽  
Embryonic Muscle ◽  
Freeze Fracture Electron Microscopy ◽  
Receptor Clusters ◽  
Alpha Bungarotoxin ◽  
Solitary Form

The development of acetylcholine receptors on Xenopus embryonic muscle cells both in culture and in situ was studied using electrophysiology and freeze-fracture electron microscopy. Acetylcholine sensitivity first appeared at developmental stage 20 and gradually increased up to about stage 31. Freeze-fracture of muscle cells that were nonsensitive to acetylcholine revealed diffusely distributed small P-face intramembraneous particles. When cells acquired sensitivity to acetylcholine, a different group of diffusely distributed large P-face particles began to appear. This group of particles was analyzed by subtracting the size distribution found on nonsensitive cells from that found on sensitive cells. We call this group of particles difference particles. The sizes of difference particles were large (peak diameter 11 nm). The density of difference particles gradually increased with development. The density of small particles (less than 9 nm) did not change with development. At later stages (32-36) aggregates of large particles appeared, which probably represent acetylcholine receptor clusters. The size distribution of difference particles was close to that of the aggregated particles, suggesting that at least part of difference particles represent diffusely distributed acetylcholine receptors. Difference particles exist mostly in solitary form (occasionally double), indicating that an acetylcholine receptor can be functional in solitary form. This result also shows that diffuse acetylcholine receptors that have previously been observed with 125I-alpha-bungarotoxin autoradiography do indeed exist in solitary forms not as microaggregates.

scholarly journals Microinjection of a monoclonal antibody against a 37-kD protein (tropomyosin 2) prevents the formation of new acetylcholine receptor clusters.

1989 ◽  
Vol 109 (5) ◽  
pp. 2337-2344 ◽  
Author(s):  
G Marazzi ◽  
F Bard ◽  
M W Klymkowsky ◽  
L L Rubin
Keyword(s):  
Monoclonal Antibody ◽  
Acetylcholine Receptor ◽  
Rous Sarcoma Virus ◽  
Acetylcholine Receptors ◽  
Neuromuscular Junctions ◽  
Muscle Cells ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Receptor Clusters

We have shown previously that chick muscle cells transformed with Rous sarcoma virus are unable to form clusters of acetylcholine receptors (AChRs) (Anthony, D. T., S. M. Schuetze, and L. L. Rubin. 1984. Proc. Natl. Acad. Sci. USA. 81:2265-2269) and are missing a 37-KD tropomyosin-like protein (TM-2) (Anthony, D. T., R. J. Jacobs-Cohen, G. Marazzi, and L. L. Rubin. 1988. J. Cell Biol. 106:1713-1721). In an attempt to clarify the role of TM-2 in the formation and/or maintenance of AChR clusters, we have microinjected a monoclonal antibody specific for TM-2 (D3-16) into normal chick muscle cells in culture. D3-16 injection blocks the formation of new clusters but does not affect the preexisting ones. In addition, TM-2 is concentrated at rat neuromuscular junctions. These data suggest that TM-2 may play an important role in promoting the formation of AChR clusters.

scholarly journals Distribution of filipin-sterol complexes on cultured muscle cells: cell-substratum contact areas associated with acetylcholine receptor clusters.

1983 ◽  
Vol 96 (2) ◽  
pp. 363-372 ◽  
Author(s):  
P C Bridgman ◽  
Y Nakajima
Keyword(s):  
Acetylcholine Receptor ◽  
Acetylcholine Receptors ◽  
Freeze Fracture ◽  
Muscle Cells ◽  
Distinct Pattern ◽  
Intramembrane Particles ◽  
Membrane Topography ◽  
Interference Contrast Microscopy ◽  
Receptor Clusters ◽  
Alpha Bungarotoxin

Specialized areas within broad, close, cell-substratum contacts seen with reflection interference contrast microscopy in cultures of Xenopus embryonic muscle cells were studied. These areas usually contained a distinct pattern of light and dark spots suggesting that the closeness of apposition between the membrane and the substratum was irregular. They coincided with areas containing acetylcholine receptor clusters identified by fluorescence labeled alpha-bungarotoxin. Freeze-fracture of the cells confirmed these observations. The membrane in these areas was highly convoluted and contained aggregates of large P-face intramembrane particles (probably representing acetylcholine receptors). If cells were fixed and then treated with the sterol-specific antibiotic filipin before fracturing, the pattern of filipin-sterol complex distribution closely followed the pattern of cell-substratum contact. Filipin-sterol complexes were in low density in the regions where the membrane contained clustered intramembrane particles. These membrane regions were away from the substratum (bright white areas in reflection interference contrast; depressions of the P-face in freeze-fracture). Filipin-sterol complexes were also in reduced density where the membrane was very close to the substratum (dark areas in reflection interference contrast; bulges of the P-face in freeze-fracture). These areas were not associated with clustered acetylcholine receptors (aggregated particles). This result suggests that filipin treatment causes little or no artefact in either acetylcholine receptor distribution or membrane topography of fixed cells and that the distribution of filipin-sterol complexes may closely parallel the microheterogeneity of membranes that exist in living cells.

scholarly journals Terahertz Absorption Characteristics of the Sodium Carboxymethyl Cellulose Colloid Based on Microfluidic Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Chenxin Ding ◽  
Bo Su ◽  
Guoyang Wang ◽  
Qinghao Meng ◽  
Jiahui Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Carboxymethyl Cellulose ◽  
Chemical Substance ◽  
Sodium Carboxymethyl Cellulose ◽  
Depth Study ◽  
Terahertz Transmission ◽  
Cellulose Concentration ◽  
Electric Field Treatment

Sodium carboxymethyl cellulose is a type of macromolecular chemical substance that is widely used in the industry for food thickening. In this study, terahertz and microfluidic technologies were combined, and a microfluidic chip with a channel depth of 50 μm was fabricated to carry samples. The terahertz characteristics of the sodium carboxymethyl cellulose colloid were studied at different concentrations and applied electric fields. The obtained results showed that different concentrations of sodium carboxymethyl cellulose have different time-domain spectra; with an increase in concentration, the terahertz transmittance of sodium carboxymethyl cellulose decreased. Under the applied electric field treatment, the longer the electric field acting time is, the higher the terahertz transmission intensity is. This approach is a safe and reliable new method for the determination of sodium carboxymethyl cellulose concentration, which provides technical support for the in-depth study of sodium carboxymethyl cellulose.

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