Biomaterial Database

Complementary structures of membrane fracture faces obtained by ultrahigh vacuum freeze-fracturing at -196 degrees C and digital image processing. 1978

O Kübler, and H Gross, and H Moor

Conventional freeze-etch replicas of the cytoplasmic fracture face (PF) of the yeast plasmalemma membrane show hexagonally ordered regions. Complementary features on the extraplasmic face (EF) could not be identified. Replicas with improved topographical resolution were obtained for both fracture faces by ultrahigh vacuum freeze-fracturing at -196 degrees C. The hexagonally ordered structure on the PF is seen to consist of volcano-like particles with a crater of 5 nm diameter. The lattice constant is 16.5 nm. On the EF, ring-like depressions corresponding to particles on the PF can occasionally be detected; the existence of ordered regions can be established by optical diffraction. Complementarity of periodic features on the PF and EF is demonstrated by digital image filtration. A main structure, coarse features of which appear on conventional PF replicas is shown to have perfect complementarity at a resolution level of 2 nm. On the EF an additional substructure, completely obscured on normal replicas, is revealed. Its complementarity remains tentative as shadows cast by the main structure impair identification of substructural features on the PF.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003201	Computers	Programmable electronic devices designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.	Calculators, Programmable,Computer Hardware,Computers, Digital,Hardware, Computer,Calculator, Programmable,Computer,Computer, Digital,Digital Computer,Digital Computers,Programmable Calculator,Programmable Calculators
D005613	Freeze Etching	A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.	Etching, Freeze
D005614	Freeze Fracturing	Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.	Fracturing, Freeze,Fracturings, Freeze,Freeze Fracturings
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker
D014618	Vacuum	A space in which the pressure is far below atmospheric pressure so that the remaining gases do not affect processes being carried on in the space.	Vacuums