Biomaterial Database

Characterization of two cell-envelope fractions from chemotrophically grown Rhodospirillum rubrum. 1975

J Oelze, and J R Golecki, and H Kleinig, and J Weckesser

Two cell-envelope fractions were isolated from chemotrophically grown cells of Rhodospirillum rubrum. On the basis of electron-microscopic investigations, chemical analysis, distribution of components involved in respiration, and poly-acrylamide gel electrophoresis, the heavy fraction (rho20 = 1.246 g per cm3) was identified as cell-wall, and the light fraction (rho = 1.145 g per cm3) as cyto-plasmic-membrane fragments. Electron micrographs showed cell-wall fragments as open structures while cytoplasmic-membrane preparations were composed of closed membrane vesicles. With respect to the main classes of chemical compounds, cell wall could be distinguished from cytoplasmic membranes by a rather low ratio of phospholipids per protein and a high ratio of carbohydrates per protein. The relative proportion of individual neutral sugars as well as phospholipids (except for lysophosphatidyl ethanolamine) revealed no significant differences between both envelope fractions. Fatty acid analysis demonstrated a higher proportion of saturated fatty acids in cell-wall than in cyto-plasmic-membrane fractions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions showed distinct protein compositions. While in cell-wall preparations polypeptides of 43,000 and 14,000 daltons predominated, 56,000- and 52,000-dalton polypeptides were the main protein subunits of cytoplasmic membranes. Cross contaminations of both cell-envelope fractions were defined.

UI	MeSH Term	Description	Entries
D008055	Lipids	A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)	Lipid
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
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
D002473	Cell Wall	The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.	Cell Walls,Wall, Cell,Walls, Cell
D002500	Centrifugation, Isopycnic	A technique used to separate particles according to their densities in a continuous density gradient. The sample is usually mixed with a solution of known gradient materials and subjected to centrifugation. Each particle sediments to the position at which the gradient density is equal to its own. The range of the density gradient is usually greater than that of the sample particles. It is used in purifying biological materials such as proteins, nucleic acids, organelles, and cell types.	Isopycnic Centrifugation
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D005643	Fucose	A six-member ring deoxysugar with the chemical formula C6H12O5. It lacks a hydroxyl group on the carbon at position 6 of the molecule.	Deoxygalactose,alpha-Fucose,alpha Fucose
D005947	Glucose	A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.	Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose