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C de Duve

Publications and source records attributed to C de Duve.

54 records · Page 3Linked to original sources
PubMed1975

Lysosomes.

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Arthritis, Rheumatoid↗
PubMed1974

Lysosomes of the arterial wall. IV. Cytochemical localization of acid phosphatase and catalase in smooth muscle cells and foam cells from rabbit atheromatous aorta.

Cytochemical methods for acid phosphatase and catalase were applied to atheromatous aortas from cholesterol-fed rabbits. Whole tissue, partially digested aortic slices and isolated cells were used for the study. Present in the atheromatous lesions were smooth muscle cells in all stages of foamy transformation, from virtually normal appearing smooth muscle cells to severely altered cells with pronounced lipid accumulation. The results with the acid phosphatase method show that lysosomes increase both in size and in number as the smooth muscle cells become foam cells. In normal appearing smooth muscle cells, acid phosphatase reaction product was found in stacked cisternae of the Golgi apparatus and in small vesicles located in the Golgi region and distributed throughout the cytoplasm. In foam cells, reaction product was found in membrane-limited vacuoles of varying size which typically contained membranous debris or myelin-like figures together with massive lipid deposits. No reaction was seen in "free" cytoplasmic lipid droplets lacking a surrounding membrane. These results confirm and extend previous biochemical findings indicating that, in the cholesterol-fed rabbit, the change from normal smooth muscle cell to foam cell is accompanied by marked physical and chemical changes of the lysosomes, including their progressive overloading with cholesteryl ester. Small diaminobenzidine-positive particles were present in normal smooth muscle cells and in those at all stages of foamy transformation. These particles were more frequent in foam cells, in agreement with the marked increase in catalase activity detected biochemically in these cells.

Acid Phosphatase↗
PubMed1973

The synthesis and turnover of rat liver of rat liver peroxisomes. IV. Biochemical pathway of catalase synthesis.

Early events in the biosynthesis of liver catalase were studied on female rats receiving [(3)H]leucine or [(3)H]delta-aminolevulinic acid or a mixture of [(3)H]leucine with [(14)C]delta-aminolevulinic acid by intraportal injection. Catalase antigen was selectively separated from homogenates by immunoprecipitation, both without and after partial purification of the enzyme. Label from both precursors appeared first in immunoprecipitable material which was lost upon purification of catalase; the label subsequently became associated with material indistinguishable from catalase. Kinetic analysis of the results indicates that the nonpurifiable material identified by early labeling consists of two distinct biosynthetic intermediates, the first lacking heme and representing about 1.6% of the total catalase content or 13 microg/g liver, the second containing heme and representing about 0.5% of the total catalase content or 4 microg/g liver. The first intermediate migrates at the same rate as catalase upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and therefore has a monomeric molecular weight of about 60,000.

Aminolevulinic Acid↗
PubMed1973

The synthesis and turnover of rat liver peroxisomes. V. Intracellular pathway of catalase synthesis.

The subcellular distribution of the biosynthetic intermediates of catalase was studied in the livers of rats receiving a mixture of [(3)H]leucine and [(14)C]delta-aminolevulinic acid by intraportal injection. Postnuclear supernates were fractionated by a one-step gradient centrifugation technique that separates the main subcellular organelles, partly on the basis of size, and partly on the basis of density. Labeled catalase and its biosynthetic intermediates were separated from the gradient fractions by immunoprecipitation, and the distributions of radioactivity were compared with those of marker enzymes. The results show that catalase protein is synthesized outside the peroxisomes, but rapidly appears in these particles, mostly still in the form of the first hemeless biosynthetic intermediate. Addition of heme and completion of the catalase molecule take place within the peroxisomes. During the first 15 min after [(3)H]leucine administration, more than half of the newly formed first intermediate was recovered in the supernatant fraction, where it was found to exist as an aposubunit of about 60,000 molecular weight.

Aminolevulinic Acid↗
PubMed1972

Cytochemical localization of acid phosphatase activity in granule fractions from rabbit polymorphonuclear leukocytes.

When rabbit peritoneal exudates (97% polymorphonuclear [PMN] leukocytes, 2% mononuclear cells) were fractionated by zonal sedimentation or isopycnic centrifugation, four fractions (A, B, C, and D) were obtained, as reported earlier. "A" consisted largely of PMN azurophil granules, "B" of PMN specific granules, and "D" of membranous elements. The source of the more heterogeneous "C" fraction (containing acid hydrolases) was uncertain. To gain further information on the nature of this fraction, cytochemical tests for acid phosphatase (AcPase) were carried out on the starting cells and on the fractions. In intact PMN, lead phosphate reaction product was found in Golgi complexes, perinuclear cisternae, and some azurophil granules (immature forms or disrupted mature forms) of a few cells. The specifics and the intact azurophils were not reactive. Reaction product was also found within Golgi cisternae, secondary lysosomes, and some of the azurophil granules of mononuclear cells. Observations on the A and B fractions confirmed those in situ regarding the localization of reaction product in disrupted PMN azurophils, its absence from specifics, and the latency of the enzyme activity in intact azurophils. In the C fraction, AcPase was found in three structures (a) Golgi cisternae, (b) dense bodies, and (c) small pleomorphic granules Comparison with the starting cells indicates that the Golgi complexes are probably derived from both PMN leukocytes and mononuclear cells, whereas the remaining elements resemble (in size, shape, and density) secondary lysosomes and azurophil granules of mononuclear cells. The results indicate that the bulk of the cytochemically detectable AcPase present in the C fraction is derived from mononuclear cells, rather than from PMN leukocytes

Acid Phosphatase↗
PubMed1967

Lysosomes in lymphoid tissue. I. The measurement of hydrolytic activities in whole homogenates.

Methods have been developed for the quantitative assay of cytochrome oxidase, esterase, and 11 acid hydrolases in rat-spleen homogenates. These methods seem to be applicable also to other lymphoid tissues. Preliminary studies, extended to nine of the acid hydrolases, indicate that these enzymes occur in partly latent and sedimentable form and that they can be unmasked and rendered soluble by some of the treatments that liberate the enzymes from rat-liver lysosomes. The spleen particles appear to be very sensitive to mechanical injury, a property which necessitates special precautions in homogenizing the tissue. Agglutination of spleen particles takes place to a larger extent in 0.25 M sucrose than in 0.15 M KCl.

Animals↗
PubMed1967

Lysosomes in lymphoid tissue. II. Intracellular distribution of acid hydrolases.

Differential centrifugation and density gradient isopycnic centrifugation have been used to fractionate homogenates of rat spleen and, in a few experiments, of rat thymus and cervical lymph nodes. The fractions have been analyzed for proteins, DNA, RNA, cytochrome oxidase, esterase, and up to 11 acid hydrolases. The results obtained indicate that the hydrolases are associated, at least largely, with cytoplasmic particles of lysosomal nature, and suggest further that these particles belong to two, and possibly three, distinct populations, perhaps reflecting the cellular heterogeneity of the tissues. The populations are identified as: (a) the L(19) population, the most important group, containing all 12 hydrolases and characterized by a modal density of about 1.19 in a sucrose-0.2 M KCl gradient; (b) the L(15) population with a modal density of 1.15, a group of apparently incomplete lysosomes containing cathepsin D and a few other enzymes, but very poor in, or entirely devoid of, several acid hydrolases, including cathepsins B and C; (c) the L(30) population, comprising all 12 enzymes and banding together with the nuclei at a density of 1.30 or higher. Lack of success in separating the latter group from the nuclei renders its significance unclear.

Acid Phosphatase↗
PubMed1967

Lysosomes in lymphoid tissue. III. Influence of various treatments of the animals on the distribution of acid hydrolases.

The density-distribution patterns of various enzymes and of labeled materials have been determined by isopycnic centrifugation in a sucrose-0.2 M KCl gradient on homogenates of lymphoid tissues from rats injected with Triton WR-1339, (14)C-labeled dextran, (51)Cr-labeled erythrocytes, and cortisol. The results confirm and extend the conclusion, derived from previous investigations on normal animals, that the lysosomes of lymphoid tissues form two and possibly three, distinct populations. The evidence indicates that the L(19) population belongs to macrophages and the L(15) group to lymphocytes. The L(30) population appears to be associated with a special type of phagocyte with a high capacity for dextran storage. All three populations seem to contribute to the activities found in soluble form in homogenates of normal lymphoid tissues.

Acid Phosphatase↗