scholarly journals Plasma Membrane Aquaporins in the Motor Cells of Samanea saman

2002 ◽  
Vol 14 (3) ◽  
pp. 727-739 ◽  
Author(s):  
Menachem Moshelion ◽  
Dirk Becker ◽  
Alexander Biela ◽  
Norbert Uehlein ◽  
Rainer Hedrich ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Motor Cells ◽  
Samanea Saman

scholarly journals Potassium Flux and Leaf Movement in Samanea saman

1974 ◽  
Vol 64 (4) ◽  
pp. 413-430 ◽  
Author(s):  
R. L. Satter ◽  
G. T. Geballe ◽  
P. B. Applewhite ◽  
A. W. Galston
Keyword(s):  
Circadian Rhythm ◽  
White Light ◽  
Electron Microprobe ◽  
Leaf Movement ◽  
Ion Pumps ◽  
Potassium Flux ◽  
Through Diffusion ◽  
Motor Cells ◽  
Samanea Saman

Samanea leaflets usually open in white light and fold together when darkened, but also open and dose with a circadian rhythm during prolonged darkness. Leaflet movement results from differential changes in the turgor and shape of motor cells on opposite sides of the pulvinus; extensor cells expand during opening and shrink during closure, while flexor cells shrink during opening and expand during closure but change shape more than size. Potassium in both open and closed pulvini is about 0.4 N. Flame photometric and electron microprobe analyses reveal that rhythmic and light-regulated postassium flux is the basis for pulvinar turgor movements. Rhythmic potassium flux during darkness in motor cells in the extensor region involves alternating predominance of inwardly directed ion pumps and leakage outward through diffusion channels, each lasting ca 12 h. White light affects the system by activating outwardly directed K+ pumps in motor cells in the flexor region.

scholarly journals Potassium Channels in Motor Cells of Samanea saman

1988 ◽  
Vol 88 (3) ◽  
pp. 643-648 ◽  
Author(s):  
Nava Moran ◽  
Gerald Ehrenstein ◽  
Kunihiko Iwasa ◽  
Charles Mischke ◽  
Charles Bare ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Motor Cells ◽  
Samanea Saman

scholarly journals Potassium Flux and Leaf Movement in Samanea saman

1974 ◽  
Vol 64 (4) ◽  
pp. 431-442 ◽  
Author(s):  
R. L. Satter ◽  
G. T. Geballe ◽  
A. W. Galston
Keyword(s):  
Differential Effect ◽  
Red Light ◽  
Leaf Movement ◽  
Phytochrome A ◽  
Level Increase ◽  
Potassium Flux ◽  
Motor Cells ◽  
Samanea Saman ◽  
Increasing Temperature

Phytochrome, a membrane-localized biliprotein whose conformation is shifted reversibly by brief red or far-red light treatments, interacts with the rhythmic oscillator to regulate leaflet movement and potassium flux in pulvinal motor cells of Samanea. Darkened pinnae exposed briefly to red light (high Pfr level) have less potassium in motor cells in the extensor region, more potassium in motor cells in the flexor region, and smaller angles than those exposed to far-red light (low Pfr level). Increase in temperature from 24° to 37° increases the differential effect of the light treatments during opening (the energetic phase) but not during closure, implying that phytochrome controls an energetic process. It seems likely that phytochrome interacts with rhythmically controlled potassium pumps in flexor and extensor cells. During nyctinastic closure of white-illuminated pinnae, exposure to far-red light before darkening results in larger angles than does exposure to red. As in rhythmic opening, the angles of all pinnae and the differential effect of the light treatments increases with increasing temperature.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Organization of the Pellicle and the Muciferous Glands in Euglena Gracilis

1970 ◽  
Vol 28 ◽  
pp. 104-105
Author(s):  
Hilton H. Mollenhauer ◽  
W. Evans
Keyword(s):  
Plasma Membrane ◽  
Euglena Gracilis ◽  
Complex Forms ◽  
Secondary Periodicity

The pellicular structure of Euglena gracilis consists of a series of relatively rigid strips (Fig. 1) composed of ridges and grooves which are helically oriented along the cell and which fuse together into a common junction at either end of the cell. The strips are predominantly protein and consist in part of a series of fibers about 50 Å in diameter spaced about 85 Å apart and with a secondary periodicity of about 450 Å. Microtubules are also present below each strip (Fig. 1) and are often considered as part of the pellicular complex. In addition, there may be another fibrous component near the base of the pellicle which has not yet been very well defined.The pellicular complex lies underneath the plasma membrane and entirely within the cell (Fig. 1). Each strip of the complex forms an overlapping junction with the adjacent strip along one side of each groove (Fig. 1), in such a way that a certain amount of sideways movement is possible between one strip and the next.

Localization of Sodium in Normal and Inhibited Transporting Epithelia

1971 ◽  
Vol 29 ◽  
pp. 392-393
Author(s):  
G. I. Kaye ◽  
J. D. Cole
Keyword(s):  
Plasma Membrane ◽  
Similar Pattern ◽  
Fixation Method ◽  
Colonic Epithelium ◽  
Gallbladder Epithelium ◽  
Rabbit Colon ◽  
Rabbit Gallbladder

For a number of years we have used an adaptation of Komnick's KSb(OH)6-OsO4 fixation method for the localization of sodium in tissues in order to study transporting epithelia under a number of different conditions. We have shown that in actively transporting rabbit gallbladder epithelium, large quantities of NaSb(OH)6 precipitate are found in the distended intercellular compartment, while localization of precipitate is confined to the inner side of the lateral plasma membrane in inactive gallbladder epithelium. A similar pattern of distribution of precipitate has been demonstrated in human and rabbit colon in active and inactive states and in the inactive colonic epithelium of hibernating frogs.

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