Phospholipid requirement of the membrane-bound Mg2+-dependent adenosinetriphosphatase in Acholeplasma laidlawii

1977 ◽  
Vol 467 (3) ◽  
pp. 346-356 ◽  
Author(s):  
E.M. Bevers ◽  
G.T. Snoek ◽  
J.A.F. Op Den Kamp ◽  
L.L.M. Van Deenen
Keyword(s):  
Acholeplasma Laidlawii ◽  
Membrane Bound

Lateral mobility of membrane-bound antibodies on the surface of Acholeplasma laidlawii: evidence for virus-induced cell fusion in a procaryote

1982 ◽  
Vol 152 (1) ◽  
pp. 471-478
Author(s):  
K Haberer ◽  
D Frösch
Keyword(s):  
Cell Fusion ◽  
Immunoelectron Microscopy ◽  
Colloidal Gold ◽  
Dynamic Processes ◽  
Cell Populations ◽  
Temperature Dependent ◽  
Lateral Mobility ◽  
Acholeplasma Laidlawii ◽  
Membrane Bound ◽  
First Time

Dynamic processes on the membrane of the procaryotic cell Acholeplasma laidlawii have been studied by means of immunoelectron microscopy. Colloidal gold-labeled anti-A. laidlawii antibodies were used as electron-dense markers. This method allowed the demonstration of temperature-dependent lateral mobility of membrane-bound immunoglobulins. By using two different sizes of gold grains to differentiate cells from two different cell populations, virus-induced fusion of procaryotic cells could be shown for the first time.

Lipid and Temperature Dependence of Membrane-Bound ATPase Activity of Acholeplasma laidlawii

1974 ◽  
Vol 52 (11) ◽  
pp. 974-980 ◽  
Author(s):  
Jean-Cheui Hsung ◽  
Leaf Huang ◽  
Daniel J. Hoy ◽  
Alfred Haug
Keyword(s):  
Atpase Activity ◽  
Anisotropy Parameter ◽  
Membrane Lipid ◽  
Paramagnetic Resonance ◽  
Lipid Fluidity ◽  
Acholeplasma Laidlawii ◽  
Straight Line ◽  
Acyl Chains ◽  
Membrane Bound ◽  
Membrane Lipid Fluidity

Arrhenius plots (15–45 °C) of the ATPase activity of Acholeplasma laidlawii membranes enriched with either arachidoyl or saturated short-chain groups exhibited a pronounced discontinuity in slope around 25–30 °C, absent in oleoyl-enriched membranes. The membrane lipid fluidity was measured with a stearic acid spin label. At the growth temperature (37 °C) the membrane lipid fluidity was identical for all three kinds of enriched membranes. For membranes enriched with saturated acyl chains, a plot of the electron paramagnetic resonance anisotropy parameter 2T11vs. the reciprocal of temperature showed a biphasic profile with a discontinuity in slope around 25–30 °C. For oleoyl-group enriched membranes this plot yields only a straight line between 15 and 50 °C. Thus, lipids do play a role in the functioning of the membrane-bound ATPase. This enzyme is probably localized in the more fluid regions of the membrane.

Two Distinct Types of Microfilaments in the Cytoplasm of Human Adenohypophysial Cells

1973 ◽  
Vol 31 ◽  
pp. 668-669
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
I. E. Stratmann ◽  
C. Ezrin
Keyword(s):  
Pituitary Tumors ◽  
Average Diameter ◽  
Anterior Lobe ◽  
Uranyl Acetate ◽  
Type I ◽  
Breast Cancer Patients ◽  
Human Pituitary ◽  
Severe Diabetes ◽  
Pituitary Glands ◽  
Membrane Bound

Surgically removed human pituitary glands as well as pituitary tumors fixed in glutaraldehyde, postfixed in osmium tetroxide, embedded in epon resin, stained with uranyl acetate and lead citrate have been investigated by electron microscopy in order to correlate ultrastructure with functional activity. In the course of this study two distinct types of microfilaments have been identified in the cytoplasm of adenohypophysiocytes.Type I microfilaments (Fig. 1) were found in the cytoplasm of anterior lobe cells of five female subjects with disseminated mammary cancer and two patients with severe diabetes mellitus. The breast cancer patients were treated pre-operatively for various periods of time with different doses of oxysteroids. The microfilaments had an average diameter of JO A, formed parallel bundles, were scattered irregularly in the cytoplasm and were frequently located in the perikaryon. They were not membrane-bound and failed to show any periodicity.

Intranuclear Crystals in Regenerating Canine Kidneys

1973 ◽  
Vol 31 ◽  
pp. 412-413
Author(s):  
D.G. Osborne ◽  
L.J. McCormack ◽  
M.O. Magnusson ◽  
W.S. Kiser
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Tubular Epithelial Cell ◽  
Tubular Epithelial Cells ◽  
Cell Nuclei ◽  
Crystalline Structures ◽  
Small Crystals ◽  
Membrane Bound

During a project in which regenerative changes were studied in autotransplanted canine kidneys, intranuclear crystals were seen in a small number of tubular epithelial cells. These crystalline structures were seen in the control specimens and also in regenerating specimens; the main differences being in size and number of them. The control specimens showed a few tubular epithelial cell nuclei almost completely occupied by large crystals that were not membrane bound. Subsequent follow-up biopsies of the same kidneys contained similar intranuclear crystals but of a much smaller size. Some of these nuclei contained several small crystals. The small crystals occurred at one week following transplantation and were seen even four weeks following transplantation. As time passed, the small crystals appeared to fuse to form larger crystals.

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