Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Membranes, Artificial: Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.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.Trimethyltin Compounds: Organic compounds composed of tin and three methyl groups. Affect mitochondrial metabolism and inhibit oxidative phosphorylation by acting directly on the energy conserving processes.Poncirus: A plant genus of the family RUTACEAE. Members contain ponfolin, a coumarin (COUMARINS).G(M1) Ganglioside: A specific monosialoganglioside that accumulates abnormally within the nervous system due to a deficiency of GM1-b-galactosidase, resulting in GM1 gangliosidosis.G(M3) Ganglioside: A ganglioside present in abnormally large amounts in the brain and liver due to a deficient biosynthetic enzyme, G(M3):UDP-N-acetylgalactosaminyltransferase. Deficiency of this enzyme prevents the formation of G(M2) ganglioside from G(M3) ganglioside and is the cause of an anabolic sphingolipidosis.G(M2) Ganglioside: A glycosphingolipid that accumulates due to a deficiency of hexosaminidase A or B (BETA-N-ACETYLHEXOSAMINIDASES), or GM2 activator protein, resulting in GANGLIOSIDOSES, heredity metabolic disorders that include TAY-SACHS DISEASE and SANDHOFF DISEASE.Gangliosides: A subclass of ACIDIC GLYCOSPHINGOLIPIDS. They contain one or more sialic acid (N-ACETYLNEURAMINIC ACID) residues. Using the Svennerholm system of abbrevations, gangliosides are designated G for ganglioside, plus subscript M, D, or T for mono-, di-, or trisialo, respectively, the subscript letter being followed by a subscript arabic numeral to indicated sequence of migration in thin-layer chromatograms. (From Oxford Dictionary of Biochemistry and Molecular Biology, 1997)Food Deprivation: The withholding of food in a structured experimental situation.Globins: A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.Xenopus: An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.Xenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.Xenopus Proteins: Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.Amphibians: VERTEBRATES belonging to the class amphibia such as frogs, toads, newts and salamanders that live in a semiaquatic environment.Clostridium perfringens: The most common etiologic agent of GAS GANGRENE. It is differentiable into several distinct types based on the distribution of twelve different toxins.Bacterial Toxins: Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Membrane Microdomains: Detergent-insoluble CELL MEMBRANE components. They are enriched in SPHINGOLIPIDS and CHOLESTEROL and clustered with glycosyl-phosphatidylinositol (GPI)-anchored proteins.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Cell Polarity: Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.Neurites: In tissue culture, hairlike projections of neurons stimulated by growth factors and other molecules. These projections may go on to form a branched tree of dendrites or a single axon or they may be reabsorbed at a later stage of development. "Neurite" may refer to any filamentous or pointed outgrowth of an embryonal or tissue-culture neural cell.Rosaniline Dyes: Compounds that contain the triphenylmethane aniline structure found in rosaniline. Many of them have a characteristic magenta color and are used as COLORING AGENTS.Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.Phosphoglycerate Mutase: An enzyme that catalyzes the conversion of 2-phospho-D-glycerate to 3-phospho-D-glycerate. EC 5.4.2.1.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Neuraminic AcidsN-Acetylneuraminic Acid: An N-acyl derivative of neuraminic acid. N-acetylneuraminic acid occurs in many polysaccharides, glycoproteins, and glycolipids in animals and bacteria. (From Dorland, 28th ed, p1518)Sialic Acids: A group of naturally occurring N-and O-acyl derivatives of the deoxyamino sugar neuraminic acid. They are ubiquitously distributed in many tissues.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Glycosphingolipids: Lipids containing at least one monosaccharide residue and either a sphingoid or a ceramide (CERAMIDES). They are subdivided into NEUTRAL GLYCOSPHINGOLIPIDS comprising monoglycosyl- and oligoglycosylsphingoids and monoglycosyl- and oligoglycosylceramides; and ACIDIC GLYCOSPHINGOLIPIDS which comprises sialosylglycosylsphingolipids (GANGLIOSIDES); SULFOGLYCOSPHINGOLIPIDS (formerly known as sulfatides), glycuronoglycosphingolipids, and phospho- and phosphonoglycosphingolipids. (From IUPAC's webpage)Viola: A plant genus of the family VIOLACEAE. Some species in this genus are called bouncing bet which is a common name more often used with SAPONARIA OFFICINALIS. Members contain macrocyclic peptides.Bence Jones Protein: An abnormal protein with unusual thermosolubility characteristics that is found in the urine of patients with MULTIPLE MYELOMA.Rickettsia rickettsii: A species of gram-negative, aerobic bacteria that is the etiologic agent of ROCKY MOUNTAIN SPOTTED FEVER. Its cells are slightly smaller and more uniform in size than those of RICKETTSIA PROWAZEKII.Rocky Mountain Spotted Fever: An acute febrile illness caused by RICKETTSIA RICKETTSII. It is transmitted to humans by bites of infected ticks and occurs only in North and South America. Characteristics include a sudden onset with headache and chills and fever lasting about two to three weeks. A cutaneous rash commonly appears on the extremities and trunk about the fourth day of illness.Pseudohypoaldosteronism: A heterogeneous group of disorders characterized by renal electrolyte transport dysfunctions. Congenital forms are rare autosomal disorders characterized by neonatal hypertension, HYPERKALEMIA, increased RENIN activity and ALDOSTERONE concentration. The Type I features HYPERKALEMIA with sodium wasting; Type II, HYPERKALEMIA without sodium wasting. Pseudohypoaldosteronism can be the result of a defective renal electrolyte transport protein or acquired after KIDNEY TRANSPLANTATION.Salivary Duct Calculi: Presence of small calculi in the terminal salivary ducts (salivary sand), or stones (larger calculi) found in the larger ducts.Accounts Payable and Receivable: Short-term debt obligations and assets occurring in the regular course of operational transactions.Eye Manifestations: Ocular disorders attendant upon non-ocular disease or injury.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Caveolae: Endocytic/exocytic CELL MEMBRANE STRUCTURES rich in glycosphingolipids, cholesterol, and lipid-anchored membrane proteins that function in ENDOCYTOSIS (potocytosis), transcytosis, and SIGNAL TRANSDUCTION. Caveolae assume various shapes from open pits to closed vesicles. Caveolar coats are composed of CAVEOLINS.Obesity: A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).Cholesterol, LDL: Cholesterol which is contained in or bound to low density lipoproteins (LDL), including CHOLESTEROL ESTERS and free cholesterol.Metabolic Diseases: Generic term for diseases caused by an abnormal metabolic process. It can be congenital due to inherited enzyme abnormality (METABOLISM, INBORN ERRORS) or acquired due to disease of an endocrine organ or failure of a metabolically important organ such as the liver. (Stedman, 26th ed)Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)