Biomaterial Database

Permeability measurements on mitochondria from wild-type and poky strains of Neurospora crassa. 1976

D M Katkocin, and C W Slayman

The permeability properties of isolated Neurospora mitochondria were determined by measuring the rate at which the mitochondria swell in isotonic solutions of various organic and inorganic molecules. Like mammalian mitochondria, wild-type Neurospora mitochondria were impermeable to sucrose and only slightly more permeable to most inorganic ions (K, Na, Cl). Their permeability to K was greatly increased by valinomycin and by monensin. In addition, the mitochondria contain specific systems mediating PO4 uptake and PO4- malate, fumarate, and succinate exchange. Mitochondria from the maternally inherited poky strain of Neurospora, previously demonstrated to possess defective ribosomes and a grossly cytochrome chain, showed a slight but significant increase in permeability to inorganic ions. They contained, however, the specific uptake and exchange systems for phosphate and dicarboxylate anions, a result suggesting that these systems do not depend upon mitochondrially synthesized polypeptides.

UI	MeSH Term	Description	Entries
D008293	Malates	Derivatives of malic acid (the structural formula: (COO-)2CH2CHOH), including its salts and esters.
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D008933	Mitochondrial Swelling	An increase in MITOCHONDRIAL VOLUME due to an influx of fluid; it occurs in hypotonic solutions due to osmotic pressure and in isotonic solutions as a result of altered permeability of the membranes of respiring mitochondria.	Giant Mitochondria,Megamitochondria,Mitochondrial Hypertrophy,Giant Mitochondrias,Hypertrophy, Mitochondrial,Megamitochondrias,Mitochondria, Giant,Mitochondrial Hypertrophies,Swelling, Mitochondrial
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009491	Neurospora	A genus of ascomycetous fungi, family Sordariaceae, order SORDARIALES, comprising bread molds. They are capable of converting tryptophan to nicotinic acid and are used extensively in genetic and enzyme research. (Dorland, 27th ed)	Neurosporas
D009492	Neurospora crassa	A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.	Chrysonilia crassa
D010539	Permeability	Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.	Permeabilities
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion