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J Remacle

Publications and source records attributed to J Remacle.

At least 145 records · Page 8Linked to original sources
PubMed1983

Microtubules and microfilaments in ageing hamster embryo fibroblasts in vitro.

Microtubules and microfilaments were investigated in hamster lung fibroblasts, during their in vitro life-span. These cells show a senescence process characterized by a drastic phenotypic change, resulting in two phenotypes: the type 1 cells, characteristic of young cultures and the type 2 cells appearing progressively with culture passages. Microtubules and microfilaments were observed at the TEM and also visualized by the unlabelled peroxidase-anti-peroxidase method. Moreover, the susceptibility of microtubules to nocodazole was tested in type 1 and 2 cells. We could not provide evidence for a different susceptibility to the drug. However the depolymerization wave occurred centripetally in type 1 cells whilst centrifugally in type 2 cells. These observations are discussed in relationship with the early arrest of division growth of the type 2 differentiated cells.

Animals↗
PubMed1982

Relationship between endoplasmic reticulum and Golgi membranes; evidence for a heterogeneous localization of cytochrome b5 in the Golgi membranes.

Cytochrome b5 has been visualized by an immunoferritin labeling in a Golgi preparation. When the Golgi apparatus was first disrupted before labeling, 60% of the profiles were clearly labeled with ferritin. This proportion of labeled vesicles was too high to be explained by contamination from other membranes. When the Golgi structure was maintained during the experimental process, obviously some small vesicles located at the periphery of the Golgi complex were labeled and at least one saccule per Golgi apparatus was labeled but only at the edges. These conclusions were sustained by a quantitative analysis which showed a low but constant labeling of Golgi saccules and tubules and a very high labeling of some small profiles. These results confirm the presence of cytochrome b5 in the Golgi apparatus but stress its heterogeneous distribution; they also sustain the idea of a possible membrane specific shuttle between the ER and the Golgi apparatus by a recycling process suggested by the presence of highly labeled small vesicles found in close vicinity with the cisternae.

Animals↗
PubMed1981

The purification of plasma membranes from WI-38 fibroblasts: effects of ageing on their composition.

A three-step method for the purification of plasma membranes from WI-38 fibroblasts was developed thus allowing the recovery of 36--44% of the plasma membrane. Except in the case of galactosyltransferase, the activity of the contaminating enzymes was very low. Morphological observations confirm the presence of a homogeneous population of vesicles. Preparations obtained from young and old cell cultures were compared for their enzymatic and protein contents. With ageing the activity of 5-nucleotidase significantly increases whereas that of alkaline phosphodiesterase I decreases. Out of the 26 components detected after sodium dodecyl sulphate polyacrylamide gel electrophoresis, four decreased but only one increased. Cellular ageing seems to fulfil a specific and localized effect on the plasma membrane.

Cell Fractionation↗
PubMed1981

Preparation and analysis of a lung microsomal fraction from control and 3-methylcholanthrene treated rats.

In order to facilitate the homogenization of lung tissue it was previously incubated with collagenase during 30 minutes. Morphological observations were performed in order to ascertain the cell integrity. The enzymatically digested tissue was homogenized in a 0.25 M sucrose solution containing 1 mM EDTA, 3 mM imidazole (pH.7.3) and supplemented with 1 mM imipramine in order to stabilize the mitochondria, which otherwise might contaminate the microsomal fraction. The homogenate was then centrifuged and subdivided into four fractions which were analyzed for their content in protein and for the activities of so-called marker enzymes. The cytochrome P450 level was measured in both control and 3-methylcholanthrene preparations. The activities and the kinetic parameters of lung benzpyrene hydroxylase and aldrin epoxidase were measured using the lung microsomal fractions from control and previously 3-methylcholanthrene treated rats; 3-methylcholanthrene pretreatment modified the catalytiac properties of both enzymes.

Animals↗
PubMed1980

The binding of cytochrome b5 to plasma membranes of rat liver: its implication for membrane specificity and biogenesis.

The in vitro incorporation of cytochrome b5 into purified plasma membranes was investigated by biochemical and immunological methods. Plasma membrane preparations incorporated three times less cytochrome b5 than did microsomal preparations; 60% of this cytochrome b5 could not be reduced by the NADH-cytochrome b5 reductase and considered as being bound to the plasma membrane. The morphological observations made after the immunochemical labeling of cytochrome b5 clearly showed a good but asymmetrical distribution of the ferritin labeling: only the inner face of the plasma membrane incorporated cytochrome b5. These results are discussed with respect to theories which concern the subcellular membrane relationships in the cell.

Animals↗
PubMed1979

[Role of the mycelium in the elimination of aflatoxin B1 from contaminated substrates].

When the aflatoxin-producing strain of Aspergillus flavus, nr 14409 developed in mixed cultures with non toxigenic strains, in solid or liquid media, it produced less aflatoxin than in pure culture. Investigations in view to elucidate the process promoting the toxin disappearance showed that the mycelium could immobilize a large amount of aflatoxin by adsorption on its walls.

Adsorption↗
PubMed1979

[Elimination of aflatoxin B1 by clays from contaminated substrates].

It has been proved that clays were able to absorb aflatoxin B1. The amount of adsorbed aflatoxin depended on the nature of clay. The adsorbing power of the clays was checked in relation to some environmental factors. From this study, it is claimed that clays are suitable for détoxification of liquid food-stuffs poisoned by aflatoxin.

Adsorption↗
PubMed1978

Binding of cytochrome b5 to membranes of isolated subcellular organelles from rat liver.

The in vitro incorporation of a well-characterized integral protein cytochrome b5 into membranes of various subcellular organelles was investigated by biochemical and immunochemical methods. Microsomes, peroxisomes, and outer mitochondrial membranes, all containing endogenous cytochrome b5, incorporated large amounts of the hemoprotein in such a way that it was reducible by an inherent NADH cytochrome b5 reductase. Lysosomal membranes did not incorporate cytochrome b5. Inner mitochondrial and Golgi membranes, which do not naturally contain cytochrome b5, bound it in vitro but it was not reduced in the presence of NADH. These results show some discrepancies between the natural localization and the in vitro binding of cytochrome b5. They confirm one aspect of the fluid membrane theory and bring new elements to our understanding of the maintenance of the specific features of the membranes of subcellular organelles with respect to the cell dynamism.

Cytochrome Reductases↗
PubMed1976

Analytical study of microsomes and isolated subcellular membranes from rat liver. V. Immunological localization of cytochrome b5 by electron microscopy: methodology and application to various subcellular fractions.

The localization of cytochrome b5 on the membranes of various subcellular organelles of rat liver was studied by a cytoimmunological procedure using anti-cytochrome b5/anti-ferritin hybrid antibodies and ferritin as label. For this study, highly purified and biochemically characterized membrane preparations were employed. Outer mitochondrial membranes were found to be heavily labeled by the hybrid antibodies whereas Golgi and plasma membranes were not marked by the reagent. Peroxisome membranes were moderately labeled by the hybrid antibodies, suggesting that they may contain some cytochrome b5. The preparation and purification of hybrid antibodies without peptic digestion is described and an analysis made of the composition of the final reagent product.

Animals↗
PubMed1976

Analytical study of microsomes and isolated subcellular membranes from rat liver. VI. Electron microscope examination of microsomes for cytochrome b5 by means of a ferritin-labeled antibody.

The distribution of cytochrome b5 in rat liver microsomes, and in two microsomal subfractions isolated by density equilibration in a linear sucrose gradient, was studied under the electron microscope by means of a ferritin-labeled hybrid anti-cytochrome b5/anti-ferritin antibody. Results of this study show that cytochrome b5 is present in essentially all microsomal vesicles derived from endoplasmic reticulum (ER), whether rough or smooth. Thus, the dissociation of ER constituents into two groups (b and c), achieved by subfractionating microsomes by isopycnic centrifugation (Beaufay, H., A. Amar-Costesec, D. Thines-Sempoux, M. Wibo, M. Robbi, and J. Berthet. 1974. J. Cell Biol. 61:213-231), does not reflect the association of each group with distinct microsomal particles but reflects rather an enzymatic heterogeneity of the ER: the ratio of group c to group b enzymes increasing with the density and ribosome load of the particles.

Animals↗