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  • 1975-1979  (4)
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Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Influence of subtotal hepatectomy on peroxisomes and peroxisomal enzymes of rat liver and isolated liver cell fractions (1975)
    Springer
    Histochemistry and cell biology 44 (1975), S. 47-56 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The activities of peroxisomal enzymes of rat liver were followed 1 to 10 days after subtotal (60–70%) hepatectomy in homogenates prepared from regenerating livers and in cell fractions isolated from them. Catalase activity was found to be depressed in the total liver homogenate (H) as well as in the mitochondrial (M) and soluble (S) fractions, while it did not change appreciably in the microsomal (Mc) and lysosomal (L) fractions, α-hydroxyacid oxidase behaved in a similar fashion. In contrast to these enzymes, urate oxidase activity remained unchanged in H, whereas it was decreased in M and increased in L and Mc during the first 5 days after operation. These results agree well with the assumption that microbody proliferation is initiated by the fragmentation of large peroxisomes. The different relations of peroxisomal enzyme activities during regeneration time are discussed with respect to the possible existence of various kinds of peroxisomes with different enzyme equipments and with different turnover rates. Biochemical examinations were paralleled to morphological and histochemical studies. An early increase in number of peroxisomes was found to occur during the first day after partial hepatectomy, which is accompanied by decrease in particle size. During the first mitotic wave (24–36 hrs post op.) the number of peroxisomes per cell was reduced to about the half. After this time number and size of the particles began to increase. Positive staining of ribosomes was frequently observed in the vicinity of peroxisomes after the application of the cytochemical catalase reaction (alkaline diaminobenzidine medium). This phenomenon is interpreted to represent rather a diffusion artifact that the cytochemical identification of newly synthesized catalase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00490420
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of clofibrate application on morphology and enzyme content of liver peroxisomes (1976)
    Springer
    Histochemistry and cell biology 46 (1976), S. 189-196 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Male albino rats (Sprague Dawley) were fed for 2–6 weeks on a diet containing 0.75% clofibrate. Liver cell fractions obtained from these animals were assayed for peroxisomal enzymes. In the cell homogenate the catalase activity was doubled, whereas the activity of urate oxidase was found to be only slightly depressed. The activity of carnitine acetyltransferase increased several times. In liver peroxisomes purified by isopycnic gradient centrifugation the specific activity of urate oxidase decreased appreciably showing that peroxisomes formed under the proliferative influence of clofibrate are not only modified with respect to their morphological characteristics but also to their enzymic equipment. This is also obvious from the changes in peroxisomal carnitine acetyltransferase activity which was enhanced by clofibrate to more than the fivefold amount. In purified mitochondria this enzyme was even more active: clofibrate advances both, the peroxisomal and the mitochondrial moiety of carnitine acetyltransferase. Morphological and cytochemical studies showed an increase in the number of microbodies and as compared to the controls microbodies were lying in groups more frequently. Small particles located closely adjacent to “normal” sized peroxisomes were found particularly after short feeding periods. While the number of coreless microbodies increased studies gave no clear evidence for an increase in marked shape irregularities of the peroxisomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02462782
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Enzymic and morphological studies on catalase positive particles from brown fat of cold adapted rats (1976)
    Springer
    Histochemistry and cell biology 50 (1976), S. 47-55 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Brown adipose tissue of normal and cold-adapted adult rats has been investigated morphologically and cytochemically. In thin sections catalase-positive particles appear as circular, oval or elongated profiles lying either as single particles or forming groups. Biochemical studies on peroxisomal enzymes show an increase of catalase activity to the tenfold amount after cold adaptation. The tissue is devoid of D-aminoacid oxidase and glycolate oxidase, while low activities of middle-chain α-hydroxyacid oxidases could be detected. The catalase-positive particles were purified by differential and isopycnic gradient centrifugation. The density of the particles (1.20 g/cm3) is lower than that of the liver peroxisomes. Enzymic investigations of the fractions render it probable that particles contain carnitine acetyltransferase, whereas they are lacking NAD-dependent glycerophosphate dehydrogenase. The pellets derived from the gradient centrifugation have been checked morphologically for purity. After performing DAB-cytochemistry for identification of the peroxidatic activity of catalase, most of the particles were shown to be structurally intact and homogeneously filled with reaction product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00492785
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Preparation of peroxisomes from carp liver by zonal rotor censity gradient centrifugation (1978)
    Springer
    Journal of molecular histology 10 (1978), S. 103-113 
    Details
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Synopsis Peroxisomes from carp liver can be separated by isopycnic density gradient centrifugation in sucrose. Without reaching complete sedimentation equilibrium, the purification by this method is quite successful. There is a 40-fold enrichment of catalase, the peroxisomal marker, with a total yield of 27%. No pretreatment of animals is necessary for separation from lysosomes, which, besides high fragility, show lower buoyant densities than peroxisomes. The enzyme content of carp liver peroxisomes is similar to that of rat liver, with the exception of α-glycerophosphate dehydrogenase, which in this tissue is a completely soluble cytoplasmic enzyme. Total activities are much lower than in the rat, for the characteristic peroxisomal oxidases the difference being in the range of one order of magnitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01003417
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    Paper (German National Licenses)
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