Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cell Fractionation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed1981

Glycerophospholipids and acyl group changes in rat brain capillary endothelial cell fraction and the liver during development.

The glycerophospholipid (GPL) content and the acyl group compositions of the ethanolamine and choline glycerophospholipids (EGP, CGP) of the isolated brain capillary cell fractions of the developing rat have been determined. The proportion of EGP/GPL increases during development, whilst CGP/GPL declines: consequently EGP/CGP increases with age. The acyl group compositions of the plasmenylethanolamine (P-GPE) and the diacyl glycerophosphocholine (D-GPC) also change during development, the proportions of saturated fatty acids (SFAs) declining and n-6 groups rising. The rates of accumulation of individual acyl groups of EGP and CGP are highest between the ages of 15 and 20 days; particularly evident is the increase in the medium chain SFAs: 16:0 and 18:0, the monoene 18:1n-9 (oleic acid) and the major-occurring polyunsaturated fatty acid, arachidonic acid, in these GPLs. These changes are compared with those of the liver where the proportion of EGP/CGP remains constant and the acyl group compositions are relatively unchanged during development. Consequently, the rates of accumulation of individual acyl groups of EGP and CGP in liver remain constant or rise slightly during this age period. These results are compared with existing accounts of the desaturation capabilities of brain and liver with age.

Aging↗
PubMed1970

In vivo incorporation of radioactive metabolites by Golgi apparatus and other cell fractions of onion stem.

Incorporation in vivo of various (14)C-labeled substrates into dictyosomes of onion (Allium cepa) stem was determined, and comparisons were made with other cell fractions on a nitrogen basis. Tissue explants were incubated for varying times in the presence of the radioactive metabolites supplied in the external medium. Fractions were then obtained from homogenates stabilized with glutaraldehyde. Purified fractions containing dictyosomes (individual stacks of cisternae) of the Golgi apparatus were obtained by centrifugation in a sucrose gradient also yielding a smooth membrane fraction free of dictyosomes. Dictyosomes were preferentially labeled with choline-1,2-(14)C and acetate-2-(14)C, suggesting that plant Golgi apparatus participate in the synthesis or modification of membrane lipids. Dictyosomes were also labeled with glucose-U-(14)C and leucine-U-(14)C, but on a molar basis incorporation was less than with choline or acetate.

Journal Article↗
PubMed2002

DNA-polymerase alpha, beta, delta and epsilon activities in isolated neuronal and astroglial cell fractions from developing and aging rat cerebral cortex.

The relative proportions of DNA-polymerases alpha, beta, delta and epsilon (pols alpha, beta, delta and epsilon ) activities in isolated neuronal and astroglial cell fractions from developing, adult and aging rat brain cerebral cortex, were examined. This was achieved through a protocol that takes advantage of the reported differential sensitivities of different DNA-polymerases towards certain inhibitors like butylphenyl and butylanilino nucleotide analogs, 2',3'-dideoxythymidine triphosphate (ddTTP), monoclonal antibody of human alpha polymerase and the use of two template primers as substrates. The results indicate that while DNA-polymerase beta (pol beta) is the predominant enzyme, significant levels of DNA-polymerases alpha and delta/epsilon (pols alpha and delta/epsilon ) are also present in both cell types at all the post-natal ages studied. A notable difference regarding the relative abundance of DNA-polymerases other than beta is the higher percentage of pol delta/epsilon in neurons and a more sustained pol alpha activity through the life span in astroglia. The presence of detectable proportion of DNA-polymerases other than beta (particularly the delta/epsilon type) may be taken to indicate their role in long patch base excision repair as well as in other modes of DNA repair.

Aging↗
PubMed1963

ENZYMES RELEASED FROM ESCHERICHIA COLI WITH THE AID OF A SERVALL CELL FRACTIONATOR.

The release and stability of the enzymes S-adenosylhomocysteine nucleosidase, lysine decarboxylase, arginine decarboxylase, glutamic decarboxylase, formic hydrogenlyase, formic oxidase, and glucose oxidase from Escherichia coli during disruption of the organisms in a Servall-Ribi refrigerated cell fractionator were examined. With the possible exception of arginine decarboxylase, maximal activity was retained by all the enzymes reported here when the cell suspensions were processed at pressures necessary for rupture of all the organisms (15,000 to 25,000 psi). Considerable variation in the stability of different enzymes liberated by disruption at higher pressures (45,000 to 55,000 psi) was observed. It is reasonable to assume that mechanical forces rather than effects of temperature are responsible for inactivation of these enzymes.

Carboxy-Lyases↗
PubMed1981

Analytical cell fractionation of isolated rabbit renal proximal tubules.

Proximal tubules were isolated in highly pure form from rabbit cortices by a mechanical procedure that is known to preserve the structural and metabolic aspects of the tubular cells. Postnuclear supernates prepared from the isolated tubules were subjects to isopycnic centrifugation in linear sucrose gradients. The enzyme activities associated with the plasma membrane (gamma-glutamyl transpeptidase, amino-peptidase M, alkaline phosphatase, Na-K-ATPase, and phosphodiesterase I) exhibited sharp unimodal frequency-density profiles with a median density near 1.16 g/ml, which shifted to a heavier density when treated with digitonin. The lysosomal enzymes, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and cathepsin B, and the peroxisomal enzyme catalase exhibited particle-associated activity near a density of 1.22 g/ml. Disruption of these particles by freezing and thawing resulted in these activities appearing in the rho = 1.10 g/ml region of the gradient where the soluble cytosolic enzyme, phosphoglucomutase, exhibited activity. Cytochrome oxidase activity typical of mitochondria gave a sharp unimodal profile at rho = 1.18 g/ml. Microsomal glucose-6-phosphatase and NADPH: cytochrome c reductase activities gave median densities near 1.16 g/ml, which did not change after incubation with digitonin. Galactosyl transferase activity gave a skewed profile at rho = 1.16 g/ml and showed a slight shift to heavier density after digitonin. This study of the enzymatic activities and density gradient distribution of the components of the proximal tubule cells provides the methodology for the further study of the cellular processing of endogenous and exogenous substances by this vital cell type.

Animals↗
PubMed1985

Retinol and retinyl esters in parenchymal and nonparenchymal rat liver cell fractions after long-term administration of ethanol.

Chronic ethanol consumption reduces the liver retinoid store in man and rat. We have studied the effect of ethanol on some aspects of retinoid metabolism in parenchymal and nonparenchymal liver cells. Rats fed 36% of total energy intake as ethanol for 5-6 weeks had the liver retinoid concentration reduced to about one-third, as compared to pair-fed controls. The reduction in liver retinoid affected both the parenchymal and the nonparenchymal cell fractions. Plasma retinol level was normal. Liver uptake of injected chylomicron [3H]retinyl ester was similar in the experimental and control group. The transport of retinoid from the parenchymal to the nonparenchymal cells was not found to be significantly retarded in the ethanol-fed rats. Despite the reduction in total retinoid level in liver, the concentrations of unesterified retinol and retinyl oleate were increased in the ethanol fed rats. Hepatic retinol esterification was not significantly affected in the ethanol-fed rats. Since our study has demonstrated that liver uptake of chylomicron retinyl ester is not impaired in the ethanol-fed rat, we suggest that liver retinoid metabolism may be increased.

Acyltransferases↗
PubMed1986

Monoamine oxidase activities in dissociated cell fractions from rat skeletal muscle.

Collagenase was used to dissociate rat skeletal muscle (gastrocnemius) into its constituent cells, from which a myocyte fraction enriched in striated muscle cells, and a non-myocyte fraction containing cells of connective tissue and vascular origin, were prepared. The activities of amine oxidase enzymes and alkaline phosphatase (AP) were then assayed in these fractions, and also in homogenates prepared from corresponding samples of non-dissociated tissue. The specific activities of the semicarbazide-sensitive amine oxidase (SSAO) and AP were considerably higher (30 to 35-fold) in non-myocyte than in myocyte fractions. AP is generally considered to be present predominantly in vascular cells of skeletal muscle, with little, if any, in skeletal muscle cells themselves. Thus, the results obtained may indicate a similar localization for SSAO activity. Support for this came from histochemical studies, which showed staining for SSAO primarily over the walls of larger blood vessels in the muscle. Unlike SSAO and AP, were marked differences in MAO-A activity between myocyte and non-myocyte fractions were not found, suggesting that MAO-A is more probably a constituent of cells within both fractions.

Alkaline Phosphatase↗
PubMed1993

Quantitative cultures of the cell fraction and supernatant of bronchoalveolar lavage fluid for the diagnosis of cytomegalovirus pneumonitis in lung transplant recipients.

Results of quantitative shell vial cultures of cell and supernatant fractions of bronchoalveolar lavage (BAL) fluid from lung transplant recipients were compared with results of transbronchial lung biopsies. Cytomegalovirus (CMV) was present in both the cell and supernatant fractions, including 28 (80%) and 29 (83%), respectively, of 35 BAL samples with corresponding biopsies that showed evidence of CMV pneumonitis and 34 (15%) and 75 (33%), respectively, of 227 BAL samples with corresponding biopsies that did not. Cultures of unseparated BAL fluid had a similar yield to cultures of supernatant. Virus titers of cell fractions and supernatants from BAL samples with corresponding biopsies that were positive for CMV pneumonitis were higher than those from BALs with negative corresponding biopsies. Culture of the unseparated fluid is recommended for simplicity and to maximize detection of CMV. Quantitative results may help in the identification of CMV pneumonitis, but additional studies are needed before quantitative cultures can be recommended for routine use.

Bronchoalveolar Lavage Fluid↗