PubMed Health⌕ Search

Biomedical subjects

E Bertoli

Publications and source records attributed to E Bertoli.

At least 109 records · Page 6Linked to original sources
PubMed1980

Superoxide dismutase content and microsomal lipid composition of tumours with different growth rates.

The content of cytosolic superoxide dismutase has been determined in Morris hepatomas 3924A (fast-growing) and 44 (slow-growing) and in ascites tumour cells (Novikoff hepatoma and Ehrlich-Lettré). The enzyme is decreased in all the tumours examined. The lowest amounts were found in the tumours with the fastest growth rates. Measurements of the lipid composition and fluidity of microsomal membranes isolated from Morris hepatomas show that also these parameters are changed in relation to the growth rate. The lipid to protein ratio and the degree of fatty acid unsaturation decrease gradually from rat liver to hepatoma 44 and 3924A microsomes. The different lipid composition is reflected also by differences in the physical environment of the bilayer, as indicated by data obtained with spin-labeled fatty acids. It is proposed that the changes in the membrane lipid composition and organization are consequent to the decrease in the protective effect of cytosolic superoxide dismutase against the O2- induced lipid peroxidation.

Animals↗
PubMed1980

Effect of some lipophilic substances on mitochondrial ATPase.

This work reports a study about the influence of some lipophilic substances like cholesterol, calciferol and tocopherol on the ATP-hydrolase activity in mitochondria. It is found that the steroids cholesterol and calciferol inhibit ATPase activity and behave like uncompetitive factors towards the enzymatic kinetics. Tocopherol, instead, affects significantly only the DCCD sensitivity of ATPase. Such effects are very probably due to the action of the physico-chemical state of th mitochondrial membrane produced by these lipophilic compounds.

Adenosine Triphosphatases↗
PubMed1980

Effect of some lipophilic substances on fluorescence polarization of perylene in lipid vesicles and mitochondrial membranes.

Short-chain ubiquinones were observed to increase the fluorescence polarization associated with perylene, indicating a decrease in the fluidity of the mitochondrial membrane. The results indicated that the perturbation induced by low homologs results indicated that the perturbation induced by low homologs of ubiquinone on the physical state of membrane lipids is quite different from that of other lipophilic substances which have been considered.

Animals↗
PubMed1979

Uncoupling effect of a low homolog of unbiquinone (UQ-3) in rabbit heart mitochondria.

Short-chain ubiquinone (UQ-3) inhibits ADP-stimulated respiration (state 3) in intact rabbit heart mitochondria. This effect appears to be similar in all the three sites of oxidative phosphorylation by using different respiratory substrates. Ubiquinone-3 also immobilizes lipids into mitochondrial membranes indicating that the uncoupling effect might be a consequence of an altered physical state of membrane lipids.

Animals↗
PubMed1979

Effect of ubiquinone-homologs on the sensitivity of mitochondrial ATPase to energy transfer inhibitors.

Short-chain ubiquinone (UQ-3) abolishes oligomycin sensitivity of ATPase in submitochondrial particles and the effect is reversed by long-chain ubiquinone (UQ-7). Ubiquinone-3 also abolishes DCCD sensitivity of ATPase in submitochondrial particles but the effect is not reversed by long-chain ubiquinones. These data suggest that ubiquinone interferes with energy transfer process by interaction with mitochondrial ATPase.

Adenosine Triphosphatases↗
PubMed1979

Studies on incorporation of CoQ-homologs in mitochondrial membranes.

In this work we have made a systematic study on the incorporation of different homologs of Coenzyme Q in mitochondrial membranes. We have used a diluted mitochondrial suspension constituting a biphasic system membrane/H2O in which exogenous Q will be distributed depending on its water solubility and on its affinity to the mitochondrial membrane. It was found that Ubiquinones are incorporated into mitochondria in different extents ranging from zero (Q1) to 10 fold (Q10) the concentration of endogenous Q per mg of mitochondrial protein. In Q-depleted mitochondria the extents of incorporation are greater for all the quinones. This study points out that there is a reflection between the isoprenoid units of each Q-homolog and its incorporation into mitochondrial membranes.

Animals↗
PubMed1979

Progressive muscular dystrophy type Duchenne. I. Spin label studies on the physico-chemical state of erythrocyte membranes.

Electron spin resonance studies of erythrocyte membranes from patients with Duchenne muscular dystrophy exhibit changes in the physical state of lipids and proteins in membranes when compared to membranes from normal subjects. The results suggest that the alterations in membrane lipid-protein organization are present in this disease.

Electron Spin Resonance Spectroscopy↗
PubMed1979

Progressive muscular dystrophy type Duchenne. II. Viscosity and resistence to erythrolytic compounds of erythrocyte membranes.

The transition temperature of erythrocyte ghosts of normal subjects is about 18-20 degrees C. We have studied the viscosity of erythrocyte ghosts of dystrophic children, showing that the transition shifts to lower temperatures (17-18 degrees C). After treatment with erythrocytic compounds like L-Lyso phosphatidyl-Choline dystrophic erythrocytes hemolize at lower Lysophosphatidyl-Choline concentration and at a greater extents than these of normal and carriers subjects.

Erythrocyte Membrane↗
PubMed1979

A role of ubiquinone in energy conservation in mitochondria.

Short chain ubiquinones (Q-3) uncouple oxidative phosphorylation in rat heart mitochondria, as shown by polarimetric experiments, and abolish P:O ratios in succinate driven oxidative phosphorylaton. The uncoupling is reversed by long chain ubiquinones (Q-7). Furthermore, short chain ubiquinones abolish oligomycin sensitivity of ATPase; the inhibition is restored by Q-7. The extraction of endogenous ubiquinone from mitochondria reversibly lowers oligomycin sensitivity of ATPase.

Animals↗
PubMed1979

Molecular mechanism of general anesthesia: II. Spin label studies on synaptic membranes.

In this communication we report the effects of general anesthetics on the mobility and order of spin labeled stearic acid derivatives in synaptic membranes and in bilayers formed from the lipids extracted therefrom. The anesthetics studied abolish the immobilization induced by synaptic membrane proteins on the membrane lipids : this effect, observed particularly in the bilayer core, is interpreted as a labilization of lipid-protein interactions induced by anesthetics.

Anesthesia, General↗
PubMed1979

Lipid protein interactions in mitochondria. VIII. Effect of general anesthetics on the mobility of spin labels in lipid vesicles and mitochondrial membranes.

We have studied the effect of general anesthetics on the mobility of two stearic acid spin labels (5-doxyl stearic acid and 16-doxyl stearic acid) in bovine heart mitochondria and in phospholipid vesicles made from either mitochondrial lipids or commercial soybean phospholipids. The general anesthetics used include nonpolar compounds (alcohols, halothane, pentane, diethyl ether, chloroform) and the amphiphatic compound, ketamine. All anesthetics tested increase the mobility of the spin labels in phospholipid vesicles to a limited extent up to a concentration where the ESR spectra become those of free spin labels. On the other hand, anesthetics have a pronounced effect on mitochondrial membranes at concentrations as low as those known to produce general anesthesia; the effect is lower near the bilayer surface (5-doxyl stearic acid) and very strong in the bilayer core (16-doxyl stearic acid). The effects of anesthetics are mimicked by the detergent, Triton X-100. We suggest that the discrepancy between the action of anesthetics in mobilizing the spin labels in lipid vesicles and in membranes results from labilization of lipid protein interactions.

Anesthetics↗