RESUMEN
The lipids extracted with CHCl(3)/MeOH mixtures from mycelium of the lower filamentous fungus Absidia corymbifera F-295 were found to contain three glycolipids. Based on the IR, 1H and 13C NMR spectra, plasma-desorption ionisation (PDI) mass spectra as well as chemical degradation results, the glycolipids were established to be 1-O-beta-D-glucopyranosyl-2-N-(2'-D-hydroxyhexadecanoyl)-9-methylsphinga-4(E),8(E)-dienine (glucosyl ceramide) and 2-O-(6'-O-beta-D-galactopyranosyl)-beta-D-galactopyranosides of 2-D-hydroxy and erythro-2,3-dihydroxy fatty acids C(9), C(11), and C(13). They accounted for about 3.4, 0.8, and 0.4%, respectively, of the total lipids extracted. No lipids identical to the above monohydroxy and dihydroxy fatty acid glycosides have been reported.
Asunto(s)
Absidia/química , Glucolípidos/química , Glucolípidos/aislamiento & purificación , Ácidos Grasos/química , Ácidos Grasos/aislamiento & purificación , Galactosilceramidas/química , Galactosilceramidas/aislamiento & purificación , Glucosilceramidas/química , Glucosilceramidas/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Estructura Molecular , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The cerebrosides produced by the soil filamentous fungus Mortierella alpina strain KG-1/95 account for about 13% of the total polar lipids extractable from lyophilised cells with chloroform/methanol mixtures. By means of 1H NMR and (13)C NMR spectroscopy, matrix-assisted laser-desorption ionisation mass spectrometry, and chemical degradation experiment, they have been shown to be 1-O-beta-D-glucopyranosyl-2-N-(2'-D-hydroxyalkanoyl)-9-methylsphinga-4(E),8(E)-dienines, the fatty acid composition of which is unusual and consists of 2-hydroxytridecanoic (4%), 2-hydroxytetradecanoic (60%), 2-hydroxypentadecanoic (20%), and 2-hydroxyhexadecanoic (16%) acids.
Asunto(s)
Cerebrósidos/química , Ácidos Grasos/análisis , Mortierella/química , Resonancia Magnética Nuclear Biomolecular , Microbiología del Suelo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Earlier, we described a new family of mesophilic, strictly autotrophic Fe(2+)-oxidizing archaebacteria, Ferroplasmaceae, which belongs to the order Thermoplasmales and includes the genus Ferroplasma and species F. acidiphilum (strain YT) [1]. The present work is concerned with a comparative study of phenotypic characteristics of the type strain YT and a new strain, F. acidiphilum Y-2, isolated from dense pulps produced during oxidation of arsenogold concentrates from the Bakyrchikskoe (Kazakhstan) and Olimpiadinskoe (Krasnoyarsk Krai) ore deposits, respectively. The G + C content of DNA from strains YT and Y-2 comprised 35.1 and 35.2 mol%, respectively; the level of DNA-DNA homology between the strains was 84%. Restriction profiles of chromosomal DNA from both strains exhibited a similarity coefficient of 0.87. Genotypic characteristics of these strains indicate their affiliation to the same species. The cells of both strains are polymorphic and lack cell walls. Strains of F. acidiphilum oxidized ferrous oxide and pyrite as the sole source of energy and fixed carbon dioxide as the sole carbon source. Strains required yeast extract as a growth factor. Optimum pH for cell growth ranged from 1.7 to 1.8; the temperature optima for the growth of strains YT and Y-2 were 34-36 and 40-42 degrees C, respectively. Comparative analysis of total lipids revealed their close similarity in the strains; two glycophospholipids comprised 90% of total lipids: lipid I, beta-D-glucopyranosylcaldarchaetidylglycerol (about 55%), and lipid II, trihexosylcaldarchaetidylglycerol (26%), whose isopranyl chains contained no cyclopentane rings. The carbohydrate fraction of lipid I hydrolysate contained only D-glucose, whereas hydrolysate of lipid II contained both D-glucose and D-galactose in a molar ratio of 2:1. Thus, it was established that the intraspecific phylogenetic divergence within F. acidiphilum is manifested in two the strains by different temperature optima against the background of similarity in other phenotypic properties.
Asunto(s)
Microbiología Ambiental , Thermoplasmales/aislamiento & purificación , Composición de Base , Dióxido de Carbono/metabolismo , Cromosomas de Archaea/genética , ADN de Archaea/análisis , ADN de Archaea/química , ADN de Archaea/genética , Compuestos Ferrosos/metabolismo , Sedimentos Geológicos/microbiología , Glucolípidos/química , Concentración de Iones de Hidrógeno , Hierro/metabolismo , Kazajstán , Lípidos/análisis , Lípidos/química , Fenotipo , Mapeo Restrictivo , Federación de Rusia , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie , Sulfuros/metabolismo , Temperatura , Thermoplasmales/citología , Thermoplasmales/fisiologíaRESUMEN
The chloroform-methanol extractable lipids of the soil filamentous fungus Absidia corymbifera VKMF-965 account for about 20% by weight of dry cells and are composed of low-polarity constituents (about 75% of the total lipids), such as triacylglycerols (mainly), diacylglycerols, sterols and free fatty acids, as well as of glycolipids (about 3%) and phospholipids. The last consist largely of components common to the fungal lipids, namely, phosphatidylethanolamine (38% of the total phospholipids), phosphatidyl-myo-inositol (16%), diphosphatidylglycerol (12%), phosphatidylcholine (7%), phosphatidic acid (6%) and phosphatidylglycerol (3%), and two unusual phospholipids, PL1 (6%) and PL2 (9%). Based on the infrared (IR), (1)H-nuclear magnetic resonance (NMR), (13)C-NMR and mass spectra along with the results of degradation experiment, these two phospholipids have been established to be 1,2-diacyl-sn-glycero-3-phospho(N-acetylethanolamine), or N-acetyl phosphatidylethanolamine, and 1,2-diacyl-sn-glycero-3-phospho(N-ethoxycarbonyl-ethanolamine), respectively. These structures have been confirmed by preparing similar phospholipids from the phosphatidylethanolamine isolated from the same fungus and correlating their chromatographic behaviour, IR and (1)H-NMR spectra with those of PL1 and PL2. So far N-acetyl phosphatidylethanolamine has been detected only in cattle and human brains and a human placenta but its structure was not rigorously proved. PL2 is a novel lipid; to our knowledge no natural phospholipid with an urethane group has yet been found. The main fatty acids of both the phospholipids are n-hexadecanoic, octadecanoic and octadecadienoic ones; PL2 contains in addition a considerable amount of octadecatrienoic acid with its greater portion located at the sn-1 position.
Asunto(s)
Absidia/química , Glicerofosfolípidos/química , Absidia/genética , Ácidos Grasos/análisis , Glicerofosfolípidos/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Estructura Molecular , Fosfatidiletanolaminas/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrofotometría InfrarrojaRESUMEN
Polar lipids comprise about 90% of the total chloroform-methanol extractable lipids of the Gram-negative, fresh-water, ring-forming bacterium Flectobacillus major FM and consist of at least 10 constituents. These are aminophosphosphingolipids, 2-N-(2'-D-hydroxy-13'-methyltetradecanoyl)-15-methyl-4(E)-hexad ecasph ingenyl-1-phosphoethanolamine (36.8% of the total polar lipids) and its 2'-deoxy derivative (3.7%); sulfonic-acid analogues of ceramide, 2-D-(2'-D-hydroxy-13'-methyltetradecanoyl)amino-3-D-hydroxy-15-met hyl hexadecane-1-sulfonic acid (18.1%) and its 2'-deoxy derivative (3. 5%); a lipoamino acid, N-[3-D-(15'-methylhexadecanoyloxy)-15-methylhexadecanoyl]-gl ycine (3. 7%); a lipodipeptide, N-¿N'-[3"-D-(15"'-methylhexadecanoyloxy)-15"-methylhexadecanoyl ]glycy l¿-L-serine (7.8%); 1,2-diacyl-sn-glycero-3-phosphoethanolamine (7. 7%), 1,2-diacyl-3-alpha-D-galactopyranosyl-sn-glycerol (2.9%); ceramide phospho-myo-inositol (4.9%), and a previously described unusual glycosphingolipid, 7-deoxy-7-amino-D-manno-heptulosonopyranosyl (1-hydroxycarbonyl-6-deoxy-6-amino-alpha-D-mannopyranosyl) ceramide (10.9%); the last two lipids contain only 15-methyl-4(E)-hexadecasphingenine as a long-chain base. The sole structural type of amide-bound fatty acids in the sphingolipids, including the sulfonic-acid analogues, is iso-15:0, either non-hydroxylated or hydroxylated at 2-C, whereas 15-methylhexadecanoic acid is the major ester-bound fatty acid in the remaining lipids.
Asunto(s)
Bacterias Aerobias Gramnegativas/metabolismo , Esfingolípidos/metabolismo , Fraccionamiento Químico , Cromatografía en Capa Delgada , Espectroscopía de Resonancia Magnética/métodos , Espectrometría de Masas , Estructura Molecular , Esfingolípidos/aislamiento & purificación , Esfingomielinas/análisisRESUMEN
The chloroform-methanol extractable lipids of the Gram-negative fresh-water bacteria Arcocella aquatica NO-502 and Flectobacillus major FM were found to contain an unusual ninhydrin-positive glycolipid. It was purified by two-stage silica gel-column chromatography. By the use of IR and (1)H-NMR spectroscopy, mass spectrometry and chemical-degradation experiment, the lipid was established to be 1-O-monoglycosyl ceramide, the carbohydrate moiety of which was the alpha-pyranose-ring form of 7-desoxy-7-amino-D-manno-heptulosonic acid, or 1-hydroxycarbonyl-6-deoxy-6-amino-alpha-D-mannopyranose. The ceramide portion consisted mainly (by 95% in the A. aquatica glycolipid and 80% in the F. major glycolipid) of 2-N-(2'-D-hydroxy-13'-methyltetradecanoyl)-15-methyl-4(E)-hexad ecasph ingenine. The minor molecular species differed from the major one only in fatty acid structure. The glycolipid accounted for 8 and 11% of the total lipids extracted from A. aquatica NO-502 and F. major FM cells, respectively.
Asunto(s)
Glicoesfingolípidos/química , Bacterias Gramnegativas/química , Glicoesfingolípidos/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Estructura Molecular , Espectrofotometría InfrarrojaRESUMEN
The extractable lipids of the gram-negative, sea-water bacterium Cyclobacterium marinus strain WH contain about 94% of polar components which consist of two phospholipids, phosphatidylethanolamine (29% of the total lipids) and phosphatidylcholine (7%), and two phosphorus-free lipids. One of the latter has been shown to be a novel sulfonic-acid analogue of ceramide, 2-D-(2'-D-hydroxy-13'-methyltetradecanoyl) amino-3-D-hydroxy-15-methylhexadec-4 (E)-en-1-sulfonic acid (48%), and other is a lipodipeptide, N-[3-d-(13'-methyltetradecanoyloxy)-15-methylhexadecanoyl] glycyl-L-serine (11%), which has so far been found only in a Flavobacterium sp. strain. The dominant fatty acid residues of the phospholipids are iso-15:0, n-16:0, 16:1 and 18:1, the acyl residues linked to the sn-1 carbon of the glycerol moiety being somewhat more saturated as compared with those located at the sn-2 position. A new procedure for determination of the absolute configuration of 2- and 3-hydroxy fatty acids is briefly described.
Asunto(s)
Ceramidas/química , Bacterias Gramnegativas/química , Lípidos/química , Ácidos Sulfónicos/química , Ácidos Grasos/análisis , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Conformación Molecular , Estructura Molecular , Péptidos/química , Fosfatidilcolinas/análisis , Fosfatidiletanolaminas/análisis , Fosfolípidos/análisisRESUMEN
The extractable lipids of the gram-negative, stalked, freshwater bacterium Caulobacter bacteroides NP-105 account for about 9.5% by weight of dry cells, polar lipids comprising up to 95% of the total. The polar lipids consist of five glycolipids, namely, 1,2-diacyl-3-alpha-D-glucopyranosyl-sn-glycerol (I) (34% of the total), 1,2-diacyl-3-alpha-D-[6'-(1",2"-diacyl-sn-glycero-3-phospho)]glucopyranosyl-sn-glycerol (II) (7%), 1,2-diacyl-3-a-D-glucuronopyranosyl-sn-glycerol (III) (17%), 1,2-diacyl-3-alpha-D-(6'-sulfo)quinovopyranosyl-sn-glycerol (V) (9%), and 1,2-diacyl-3-alpha-D-[4'-(alpha-D-glucopyranosyl)] glucuronopyranosyl-sn-glycerol (VI) (28%), and one glycerophospholipid, 1,2-diacyl-sn-glycero-3-phosphoglycerol (IV) (5%). The main fatty acyls of the lipids are n-16:0, cis-18:1 omega7, and cis-11,12-methyleneoctadecanoic (lactobacillic) acid residue. Of the 6 lipids listed, only 3 (I, IV, and V) can be treated as widely encountered. However, sulfonic glycolipid V is a characteristic lipid component of photosynthetic organisms rather than non-photosynthetic ones. Phosphatidyl derivatives of glycosyldiacylglycerols of type II normally occur in gram-positive bacteria, among gram-negative bacteria they have been revealed only in two species of the Pseudomonas genus. Glucuronosyl and alpha-glucosyl-a-glucuronosyl diacylglycerols such as III and VI, respectively, are very rare lipids, the latter being found so far only in a Streptomyces strain.
Asunto(s)
Caulobacter/química , Lípidos/aislamiento & purificación , Cromatografía en Capa Delgada , Ácidos Grasos/análisis , Glucolípidos/análisis , Lípidos/análisis , Espectroscopía de Resonancia MagnéticaRESUMEN
The triacylglycerol fraction of lipids extracted from sclerotia of the rye ergot Claviceps purpurea strain VKM F-2642D has been shown to comprise about 60% of the total lipids and to consist of at least seven constituents, namely, [R]-[R]-[R] (1.6% of the total fraction), [R-Ric]-[R]-[R] (27%), [R-Ric]-[R-Ric]-[R] (65%), [R-Ric]-[R-Ric]-[R-Ric] (4.8%), [R-Ric-Ric]-[R-Ric]-[R-Ric] (1.1%), [R-Ric-Ric]-[R-Ric-Ric]-[R-Ric] (0.3%), and [R-Ric-Ric-Ric]-[R-Ric-Ric]-[R-Ric-Ric] (0.2%) (acyl residues at the 1(3), 2 and 3(1) positions of the glycerol moiety are indicated; R = nonhydroxylated fatty acid (C16, C18) residue, Ric = ricinoleyl residue). Non-hydroxylated fatty acyls (R) are n-16:0 (25-50% of the total), 16:1 omega 7 (10-15%), n-18:0 (2-5%), 18:1 omega 9 (20-30%), and 18:2 omega 6,9 (10-35%). The second and the third of the listed triacylglycerols are composed dominantly (by 86% or more) of 1,2-di-[R]-3-[R-Ric]-sn-glycerol and 1-[R]-2,3-di-[R-Ric]-sn-glycerol, respectively.
Asunto(s)
Claviceps/química , Triglicéridos/química , Animales , Cromatografía , Alcaloides de Claviceps/análisis , Alcaloides de Claviceps/química , Larva , Espectroscopía de Resonancia Magnética , Espectrofotometría Infrarroja , Estereoisomerismo , Triglicéridos/análisis , Triglicéridos/aislamiento & purificaciónRESUMEN
The extractable polar lipids of the gram-negative, budding, seawater bacterium Hyphomonas jannaschiana VP-2T were shown to consist of five glycolipids, namely, 1,2-diacyl-3-alpha-D-glucopyranosyl-sn-glycerol (I) (25% of the total lipids), 1,2-diacyl-3-alpha-D-glucuronopyranosyl-sn-glycerol (II) (41%), taurine-amide of II (III) (32%), acyl-D-glucuronopyranoside (IV) (0.9%), and acyl-3-O-acyl-D-glucuronopyranoside (V) (0.4%); glycolipid (III) was described by the authors previously. In addition, small amounts of poly(beta-hydroxybutyrate) and free fatty acids were present in the lipids extracted. Neither phospholipids nor low-polarity lipids, such as fatty acid esters of glycerol or fatty alcohols, were detected. Glycolipids I, II, IV, V were isolated in chromatographically pure state by chromatography on DEAE-cellulose and silica-gel columns. Their structures were established using chromatographic, spectrometric and chemical-degradation methods. In glyceroglycolipids I and II, unsaturated fatty acid residues were located predominantly at the sn-1 carbon of the glycerol moiety while saturated ones were linked mainly to the sn-2 carbon.
Asunto(s)
Glucolípidos/química , Bacterias Gramnegativas/química , Glucósidos/química , Glucuronatos/química , Glicéridos/química , Espectrometría de Masas , Fosfolípidos/análisis , Agua de Mar/microbiología , Estereoisomerismo , Taurina/análogos & derivadosRESUMEN
The extractable lipids of the PC-producing, methylotrophic, budding bacterium Hyphomicrobium vulgare NP-160 grown in a mineral-salts medium containing methanol as the carbon source, were studied by chromatographic and spectrometric methods. They were found to be comprised of PC (35% of the total lipids), PDME (33%), PMME (1%), PE (9%), PG (10%), DPG (6%), and a non-phosphorus, ornithine-containing lipoamino acid, OL (6%). No low-polarity lipids, such as fatty acid esters of glycerol or of other alcohols, were detected. The sole fatty-acyl constituents of PDME and PMME were cis-octadec-11-enoic (cis-vaccenic) acid residues, whereas the other phospholipids contained, in addition, 1 to 5 mol % of MOA (lactobacillic acid) residues located predominantly at the sn-1 position of their glycerol residues. OL consisted of two molecular species, 2-N-[3'-(cis-octadec-11"-enoyloxy)octadecanoyl]-L- ornithine and 2-N-[3'-(cis-11", 12"-methyleneoctadecanoyloxy)octadecanoyl]-L-ornithine in the molar ratio 94:6. When the culture medium was devoid of phosphate, a threefold increase in OL together with a three-fold decrease in PE were observed, no significant changes in proportions of the remaining lipids occurring. The most striking feature of the lipid composition in this case was the presence of considerable amounts of fatty acid methyl esters, mainly methyl cis-vaccenate, along with minute amounts of wax esters.
Asunto(s)
Bacterias/química , Lípidos/análisis , Fosfatidilcolinas/biosíntesis , Bacterias/metabolismo , Cardiolipinas/análisis , Cromatografía de Gases , Cromatografía en Capa Delgada , Espectroscopía de Resonancia Magnética , Fosfatidilcolinas/análisis , Fosfatidiletanolaminas/análisis , Fosfolipasas A/metabolismoRESUMEN
A previously unknown glycolipid has been isolated from the budding seawater bacterium Hyphomonas jannaschiana VP-2T devoid of phospholipids. Using a combination of chromatographic, spectrometric, enzymic- and chemical-degradation methods, the structure of the lipid has been determined to be 1,2-diacyl-3-alpha-D-glucuronopyranosyl-sn-glycerol taurineamide. Its main fatty acyls are n-16:0, cis-16:1 omega 7, n-18:0, cis-18:1 omega 7, and n-19:0. The hydroxyl at the sn-1 position of the glycerol residue is acylated predominantly with unsaturated fatty acids, and the secondary hydroxyl at the sn-2 carbon is acylated mainly with saturated ones.
Asunto(s)
Bacterias/química , Glucolípidos/aislamiento & purificación , Cromatografía de Gases , Cromatografía en Capa Delgada , Ácidos Grasos/análisis , Glucolípidos/química , Glucolípidos/metabolismo , Concentración de Iones de Hidrógeno , Hidrólisis , Lipasa/metabolismo , Espectrometría de Masas , Conformación Molecular , Estructura Molecular , Agua de Mar/microbiologíaRESUMEN
2-(4-Hydroxyphenyl)ethane-1-ol (tyrosol) and 5-n-alkyl(C19,C21)resorcinols produced by some microorganisms as anabiosis autoregulators (factors d1) inhibit the electron transport and uncouple oxidative phosphorylation in the respiratory chain of rat liver mitochondria: a 50% decrease of the respiratory control is caused by 0.32-0.36 mumol of tyrosol or by 0.21-0.26 mumol of alkylresorcinols per mg of protein. Alkylresorcinols reduce the NADH-dehydrogenase and succinate dehydrogenase activities in mitochondria, whereas tyrosol acts predominantly on the NADH-dehydrogenase activity.
Asunto(s)
Mitocondrias Hepáticas/metabolismo , Alcohol Feniletílico/análogos & derivados , Resorcinoles/farmacología , Saccharomyces cerevisiae/química , Animales , Transporte de Electrón/efectos de los fármacos , Mitocondrias Hepáticas/enzimología , NADH Deshidrogenasa/metabolismo , Alcohol Feniletílico/farmacología , Ratas , Ratas Wistar , Saccharomyces cerevisiae/fisiología , Succinato Deshidrogenasa/metabolismoRESUMEN
The protein fractions precipitated by ammonium sulfate from the bovine, human and Greenland's seal blood sera enhanced the pain sensitivity of mice, rats and rabbits. The proteins fraction of the seal blood serum was divided in six subfractions by ion-exchange chromatography. One of these subfractions clearly showed hyperalgesic properties, while the others had an opposite effect. The collagenase hydrolysate of the same protein fraction had an analgetic activity. The results of this and previous studies suggest the occurrence of one more nociception-regulating protein-peptide system in mammals.
Asunto(s)
Analgésicos/farmacología , Proteínas Sanguíneas/farmacología , Animales , Proteínas Sanguíneas/aislamiento & purificación , Bovinos , Cromatografía por Intercambio Iónico , Humanos , Masculino , Ratones , Ratones Endogámicos CBA , Nalorfina/farmacología , Naloxona/farmacología , Dimensión del Dolor , Conejos , Ratas , Ratas Wistar , PhocidaeRESUMEN
The autoregulatory d1 factor of the yeast, Saccharomyces cerevisiae, that induces the transition of vegetative cells into refractory resting forms, has been isolated from the cell-free culture medium as an individual crystalline compound. It has been shown to be 2-(4-hydroxyphenyl)ethane-1-ol which is also known as tyrosol. When added to the producer culture at 5-15 microM concentration, tyrosol stimulated the endogenous respiration of cells, but inhibited at 20-80 microM concentration. At 200-800 microM concentration, it induced the occurrence of resting forms. The action of tyrosol was not specific, for it also inhibited the cell respiration of the bacteria, Escherichia coli and Bacillus cereus, at 64-86 microM concentration.
Asunto(s)
Alcohol Feniletílico/análogos & derivados , Feromonas/aislamiento & purificación , Saccharomyces cerevisiae/química , Homeostasis/fisiología , Alcohol Feniletílico/química , Alcohol Feniletílico/aislamiento & purificación , Feromonas/químicaAsunto(s)
Frío/efectos adversos , Hipotermia/tratamiento farmacológico , Reno , Bazo , Extractos de Tejidos/uso terapéutico , Animales , Evaluación Preclínica de Medicamentos , Hipotermia/mortalidad , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Extractos de Tejidos/aislamiento & purificaciónAsunto(s)
Bolsa de Fabricio/fisiología , Frío/efectos adversos , Péptidos/farmacología , Animales , Pollos , Femenino , Inmunidad Innata/efectos de los fármacos , Inyecciones Intraperitoneales , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Péptidos/aislamiento & purificación , SolucionesRESUMEN
To investigate the mechanism by which 5-n-alkyl(C19-C25)-resorcinols synthesized by certain bacteria of the Azotobacter genus affect the lipid bilayers of cellular membranes, planar bimolecular membranes were formed from these alkyl-resorcinols and from mixtures of those and typical bacterial phospholipids such as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The electrical properties and, in some instances, the stability of the prepared membranes have been studied. The alkylresorcinols have been found to associate with phospholipids to form oligomeric and polymeric complexes, thereby giving rise to modifications in the bilayer structure and properties. It has been shown that the same compounds suppress the mitochondrial respiration in the presence of NAD-dependent substrates, but they activate it if succinate is used as substrate. This fact is explained in terms of the interaction between the alkylresorcinols and membrane phospholipids.
Asunto(s)
Azotobacter/química , Membrana Celular/química , Membrana Dobles de Lípidos/química , Resorcinoles/farmacología , Animales , Azotobacter/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Conductividad Eléctrica , Ácidos Grasos/química , Lípidos de la Membrana/química , Mitocondrias Hepáticas/química , Fosfolípidos/química , Ratas , Ratas EndogámicasRESUMEN
The influence of 2-methoxy-6-alkyl(C19-C25)benzoquinones-1,4 and 4-methoxy-6-alkyl(C19-C25)benzoquinones-1,2 on the respiration of isolated rat liver mitochondria has been studied. As a concentration of each of the quinones increased gradually from zero, the rate of the respiration using NAD-dependent substrates firstly increased but then decreased, 1,2-quinones being the more potent inhibitors. Concurrently, the respiratory control of mitochondria was lowered, indicating uncoupling effect of these quinones. With succinate the latter exhibited moderately accelerating effect. Uncoupled by 2,4-dinitrophenol, the respiration was stimulated by the both preparations in the presence of succinate but was suppressed when NAD-dependent substrates were used. The observed inhibitory effects have been assumed to be caused by a competition between the quinones and endogenous co-enzyme Q for the active site of NADH-dehydrogenase complex of the respiratory chain.