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P Messner

Publications and source records attributed to P Messner.

122 records · Page 7Linked to original sources
PubMed1978

Freeze-fracturing in normal vacuum reveals ringlike yeast plasmalemma structures.

The fine structure of the regular arrays of subunits seen on both plasmalemma fracture faces in resting and starved Saccharomyces cerevisiae (baker's yeast) has been compared using different freeze-fracture replication methods. Freeze-cleaving was carried out at 173 degrees, 133 degrees, and 108 degrees K under a vacuum of 2 X 10(-7) torr (2.6 X 10(- 7)mbar) or under liquid nitrogen at atmosphereic pressure. Independent of the preparation conditions (fracturing temperature, and whether cleaved under vacuum or liquid nitrogen), resting and starved yeast show a significant difference in the morphology of the subunits forming the regular arrays. The regularly arranged particles of the P face of the plasmalemma of starved yeast have a clear craterlike structure which has previously been reported to be demonstrated only by freeze-etching at very low temperatures in ultrahigh vacuum. A complementary structure is seen on the plasmalemma E face. Prolonged exposures of fracture faces under the protection of liquid nitrogen-cooled shrouds have shown that, because of the consequent drastic reduction of condensable gases in the specimen area, no detectable condensation contamination of exposed fracture faces occurs within 15 min at a specimen temperature of 108 degrees K. This shows that a complicated ultrahigh vacuum technology is not required for high resolution freeze- etching.

Cell Membrane↗
PubMed1977

Immunoglobulin class of antilymphocyte antibodies in systemic lupus erythematosus patients and their families.

Antilymphocyte antibody (ALA) in systemic lupus erythematosus (SLE) was studied using an indirect immunofluorescent technique with air-dried, acetone-fixed lymphocytes. Ninety-four per cent of patients with SLE and 65 per cent of their relatives had ALA. The ALA response in SLE patients involved antibodies of all classes. However, the ALA in their relatives was primarily of the IgM class. Restriction of the class of ALA in asymptomatic relatives is analogous to that seen with anti-RNA antibodies and suggests that the switch to production of autoantibodies of the IgG class may be important in the pathogenesis of SLE.

Antibodies↗
PubMedDate not supplied

Characterization of the ultrastructure and the self-assembly of the surface layer of Bacillus stearothermophilus strain NRS 2004/3a.

The ultrastructure of the crystalline surface layer (S-layer) of Bacillus stearothermophilus strain NRS 2004/3a has been characterized by electron microscopy supplemented by optical and computer image analysis. The S-layer, composed of glycoprotein subunits, has oblique symmetry, and can be extracted by guanidine hydrochloride. Upon dialysis, this extract produced both flat and cylindrical mono- and double-layer self-assembly products. Optical diffraction analysis of negatively stained preparations showed five types of double-layered assembly products. Computer filtering separated the double-layer complexes and revealed them to be composed of a common monolayer with p2-symmetry (a = 9.4 nm, b = 11.6 nm, and gamma = ca. 78 degrees). By analysis of freeze-dried and heavy metal-shadowed self-assemblies the surface topography and the characteristic "handedness" of the morphological units have been determined. Labeling with polycationic ferritin has shown that each surface of the S-layer possessed a different net charge. The results indicate that S-layers in vivo could prevent autoagglutination of cells.

Cell Membrane↗