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  • 1
    Electronic Resource
    Electronic Resource
    The Importance of Microtubules in Determination of Shape and Intracellular Distribution of Peroxisomes (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 804 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb18660.x
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  • 2
    Electronic Resource
    Electronic Resource
    Nonradioactive in Situ Hybridization for Detection of mRNAs of Peroxisomal Enzymes in Rat Liver (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 804 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb18685.x
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  • 3
    Electronic Resource
    Electronic Resource
    Immunocytochemical investigation of catalase and peroxisomal lipid β-oxidation enzymes in human hepatocellular tumors and liver cirrhosis (1999)
    Springer
    Virchows Archiv 435 (1999), S. 486-495 
    Details
    ISSN: 1432-2307
    Keywords: Key words Peroxisomes ; Hepatocellular tumors ; Immunocytochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A significant reduction of catalase activity, a peroxisomal marker enzyme, occurs in human hepatic neoplasias, but no information is available on other peroxisomal proteins. We have studied by means of immunohistochemistry four specific proteins of peroxisomes (catalase and three enzymes of lipid β-oxidation) in human hepatocellular tumors of various differentiation grades from adenoma to anaplastic carcinoma. In all tumors, except the adenomas, the tumor cells contained fewer peroxisomes than extrafocal hepatocytes and the reduction of antigenic sites in the tumor types generally correlated with the degree of tumor dedifferentiation as assessed by classical histopathological criteria. Two poorly differentiated tumors had no detectable peroxisomes at all. There were no major differences in the intensities of the immunocytochemical staining for all four studied peroxisomal antigens in different tumors, suggesting that the neoplastic transformation affects the biogenesis of the entire organelle and not merely the individual peroxisomal enzyme proteins. Some tumors exhibited a distinct peripheral distribution of peroxisomes. In cases with associated liver cirrhosis, the hepatocytes in the adjacent liver showed marked peroxisome proliferation, forming large perinuclear aggregates, occupying occasionally the entire cytoplasm. Taken together, our observations indicate that peroxisomes are significantly altered in both hepatocellular tumors and liver cirrhosis and, thus, could be responsible for some of the metabolic derangements observed in those disease processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050432
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  • 4
    Electronic Resource
    Electronic Resource
    The importance of tissue fixation for light microscopic immunohistochemical localization of peroxisomal proteins: the superiority of Carnoy's fixative over Baker's formalin and Bouin's solution (1995)
    Springer
    Histochemistry and cell biology 103 (1995), S. 187-195 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have compared the effects of fixation with three commonly used fixatives upon preservation of the antigenicity of six peroxisomal proteins in rat liver using both immunohistochemical staining and Western blotting of fixed tissue extracts. The immunoreactivity of all six peroxisomal proteins was well preserved and peroxisomes were clearly identified in material fixed in Carnoy's fixative. Moreover, the corresponding proteins stained well in Western blots prepared from extracts of Carnoyfixed material. The intensity of the immunohistochemical staining was reduced at different rates for individual peroxisomal proteins after fixation in Baker's formalin, but peroxisomes were still well visualized with antibodies to catalase and some β-oxidation enzymes. No evidence of immunohistochemical staining for any peroxisomal antigens was obtained after fixation in Bouin's fluid. For detection of the antibody binding sites in Carnoy's fixed material, the avidin-biotin-peroxidase complex (ABC) with aminoethyl carbazole as chromogen was found to be superior to the methods of peroxidase-antiperoxidase/diaminobenzidine and protein A-gold with silver intensification. Using Carnoy-fixative and the ABC-method, we demonstrate light microscopic immunohistochemical localization of peroxisomal antigens in several rat tissues as well as in human post-mortem liver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01454023
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  • 5
    Electronic Resource
    Electronic Resource
    Detection of mRNAs encoding peroxisomal proteins by non-radioactive in situ hybridization with digoxigenin-labelled cRNAs (1997)
    Springer
    Histochemistry and cell biology 108 (1997), S. 371-379 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have used a non-radioactive in situ hybridization (ISH) protocol for the detection of mRNAs encoding proteins localized in peroxisomes. In this presentation the literature on detection of ”peroxisomal mRNAs” is reviewed and the results obtained by application of the non-radioactive method are compared with those obtained by hybridization with radioactive probes. Moreover, the special processing conditions and the application of the method for the specific visualization of mRNAs coding for several peroxisomal proteins with different abundance levels and distinct tissue distributions are presented. The combination of the following technical details in the ISH procedure were found to be essential for obtaining optimal sensitivity and good histological quality of the preparations: (a) perfusion-fixation with a fixative containing 4% depolymerized paraformaldehyde/0.05% glutaraldehyde, (b) the use of paraffin embedding instead of frozen sections, (c) specific proteinase K-digestion time for each tissue, and (d) the use of digoxigenin-labelled cRNA probes (hydrolyzed to a length of about 200 bases) for detection. By using this technique, we were able to localize several peroxisome-specific mRNAs with different degrees of abundance: (1) high-level (catalase and urate oxidase) and (2) low-level (all β-oxidation enzymes and the 70-kDa peroxisomal membrane protein) in rat liver and kidney. The specificity of the method was confirmed by the negative results obtained with corresponding sense controls and the distinct positive staining patterns obtained for albumin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNAs. All transcripts for mRNAs encoding peroxisomal proteins were localized to the cytoplasm of hepatocytes, with all nuclei as well as epithelial cells of bile ducts and sinusoidal cells remaining negative. In rat kidney, the catalase transcripts were confined to proximal tubular epithelial cells, which is consistent with the high abundance of peroxisomes in this part of the nephron. In contrast, no transcripts for urate oxidase were present in the kidney, corresponding to the absence of that protein in this organ. The transcripts for GAPDH on the other hand were localized in proximal and distal tubular epithelial cells as well as in collecting ducts. The application of this technique to the rat adrenal gland and testis in recent unpublished studies have revealed exclusive localization of catalase transcripts to the adrenal cortex and to interstitial cells of Leydig, which are known to be rich in microperoxisomes. These observations demonstrate the suitability of this technique for accurate localization of mRNAs encoding peroxisomal proteins and for the analysis of alterations in the expression of the corresponding genes under different experimental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050178
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  • 6
    Electronic Resource
    Electronic Resource
    Species differences in induction of hepatic enzymes by BM 17.0744, an activator of peroxisome proliferator-activated receptor alpha (PPARα) (1999)
    Springer
    Archives of toxicology 73 (1999), S. 440-450 
    Details
    ISSN: 1432-0738
    Keywords: Key words BM 17.0744 ; β-Oxidation pathway ; Peroxisomes ; Peroxisome proliferators ; Species differences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract BM 17.0744, a new anti-diabetic and lipid-lowering agent, leads also to strong hepatomegaly and carnitine acetyl transferase (CAT) increase in the liver of rats, a phenomenon known from fibrates. For information on the relevance of changes in liver of rats to other species, we investigated the effects of BM 17.0744 on lipids and selected marker enzymes related to β-oxidation in rats, dogs and guinea-pigs, so-called high and low responders to peroxisome proliferators. To examine selectivity other enzymes were also determined, e.g. esterase, urate oxidase (UOX) and cytochrome c oxidase (CYT.C.OX.). Lowering of triglycerides and cholesterol in blood serum and/or liver was observed in pharmacological dose range in the three species tested. In dogs and guinea-pigs, liver and kidney weights were unaffected even in dogs in medium and high dose groups with high systemic exposure and severe toxicity. In male Sprague-Dawley rats treatment with 1.5, 3, 6 and 12.5 mg/kg per day BM 17.0744 selectively elevated the activities of CAT and acyl-CoA oxidase (AOX) by ≤200 and 20-fold, respectively. Administration of BM 17.0744 to Beagle dogs (1.5, 4, 12 mg/kg per day) and guinea-pigs (3 and 12 mg/kg per day) enhanced the activities of CAT and AOX dose-dependently by a factor of two to three only. Immunoblotting revealed a drug-specific enhancement of the amount of β-oxidation enzymes in rats, which is in accord with the rapid and coordinated transcriptional activation shown in Northern dot blot analysis. Nuclear run-on assays demostrated a real transcriptional activation. BM 17.0744 activates peroxisome proliferator-activated receptor α (PPARα), which could be shown by transactivation assays. The stimulation of PPARα by BM 17.0744 was stronger than that of the known ligands WY 14.643 and ETYA. Activation of PPARγ can be excluded. Taken collectively, the data demonstrate an enhancement of the β-oxidation system by BM 17.0744 paralleled by lipid-lowering in all species investigated. The activation of the nuclear factor PPARα may explain the changes in liver and the metabolic effects on the molecular level. The lack of an increase in liver and kidney weights and the relatively moderate enhancement of activities of β-oxidation-related enzymes in dogs and guinea-pigs indicate that the excessive response observed in rats is not applicable to other, predominantly non-rodent, species. On the basis of these data and the experience with fibrates a specific risk for humans is not expected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050633
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructural, immunocytochemical and morphometric characterization of liver peroxisomes in gray mullet, Mugil cephalus (1999)
    Springer
    Cell & tissue research 297 (1999), S. 493-502 
    Details
    ISSN: 1432-0878
    Keywords: Key words Liver peroxisomes ; Catalase ; Palmitoyl-CoA oxidase ; DAB cytochemistry ; Morphometry ; Immunochemical methods ; Mugil cephalus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Peroxisomes of the hepatocytes of gray mullets, Mugil cephalus, were characterized cytochemically and immunocytochemically using antibodies against the peroxisomal proteins catalase and palmitoyl-coenzyme A (CoA) oxidase. In addition, morphometric parameters of peroxisomes were investigated depending on the hepatic zonation, the age of the animals and the sampling season. Mullet liver peroxisomes were reactive for diaminobenzidine, but presented a marked heterogeneity in staining intensity. Most of the peroxisomes were spherical or oval in shape, although irregular forms were also observed. Their size was heterogeneous, with profile diameters ranging from 0.2 to 3 µm. Peroxisomes tended to occur in clusters, usually near the mitochondria and lipid droplets. They also showed a very close topographical relationship to the smooth endoplasmic reticulum. Mullet liver peroxisomes did not contain cores or nucleoids as rodent liver peroxisomes, but internal substructures were observed in the matrix, consisting of small tubules about 60 nm in diameter and larger semicircles 120 nm in diameter. The volume density of peroxisomes was higher in periportal hepatocytes of mullets sampled in summer than in pericentral hepatocytes, indicating that mullet peroxisomes vary depending on physiological and environmental conditions. By immunoblotting, the mammalian antibodies cross-react with the corresponding proteins in whole homogenates of mullet liver. Paraffin sections immunostained with the antibodies against catalase and palmitoyl-CoA oxidase showed a positive reaction corresponding to peroxisomes localized in the hepatocyte cytoplasm. In agreement, the ultrastructural study revealed that catalase and palmitoyl-CoA oxidase are exclusively localized in the peroxisomal matrix in fish hepatocytes, showing a dense gold labeling. The presence of the peroxisomal β-oxidation enzyme palmitoyl-CoA oxidase in peroxisomes indicated that these organelles play a key role in the lipid metabolism of fish liver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051376
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  • 8
    Electronic Resource
    Electronic Resource
    Isolation of peroxisome subpopulations from rat liver by means of immune free-flow electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1140-1144 
    Details
    ISSN: 0173-0835
    Keywords: Isolation ; Peroxisome subpopulations ; Immune free-flow electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Immune free-flow electrophoresis (IFFE) has been applied to the separation of peroxisomes (PO). IFFE is a modification of antigen-specific electrophoretic cell separation (ASECS), and combines the advantages of electrophoretic separation with the high selectivity of an immune reaction. It differs from the latter in the pH of the electrophoresis buffer, which was shifted from the physiological range (ASECS) to the pI of IgG molecules (pH ∼ 8.0), thus further decreasing the mobility produced by the binding of a specific antibody. This enhances the mobility differences between IgG-coupled particles and those nondecorated, with resultant improved separation. We have now succeeded in isolating different subpopulations of PO by applying IFFE to heavy, light, and post-mitochondrial fractions separated by differential centrifugation of a rat liver homogenate. The obtained PO subfractions differed in their composition of matrix and membrane proteins, as revealed by immunoblotting. This indicates that they indeed represent distinct subpopulations of rat hepatic PO.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190714
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  • 9
    Electronic Resource
    Electronic Resource
    Isolation of rat hepatic peroxisomes by means of immune free flow electrophoresis (1997)
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 774-780 
    Details
    ISSN: 0173-0835
    Keywords: Isolation ; Peroxisomes ; Immune free flow electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Rat hepatic peroxisomes (PO) were separated from other cell organelles by free flow electrophoresis (FFE) in combination with immunocomplexing PO prior to FFE with an antibody directed against the cytoplasmic aspect of the peroxisomal membrane protein PMP 70. This novel approach is based on a method termed antigen-specific electrophoretic cell separation (ASECS) which was originally introduced for the isolation of human T and B lymphocyte subpopulations by Hansen and Hannig (J. Immunol. Methods 1982, 51, 197-208). We adapted this technique to PO isolation from a crude peroxisomal fraction, streamlining it by the following modifications: (i) The sandwich-technique recommended to further lower a negative surface charge was renounced. (ii) Instead, the pH of the electrophoresis buffer was raised from 7.2 to 8.0, thus minimizing the electrophoretic mobility of the particles immunocomplexed due to the fact that the isoelectric point (pI) of IgG molecules is close to pH 8.0. PO isolated by this modification, referred to as immune free flow electrophoresis (IFFE), are as pure, intact, and structurally well-preserved as are highly purified PO obtained by density gradient centrifugation. The technique is currently applied for the isolation of peroxisomal subpopulations that are difficult to obtain by means of density gradient centrifugationPresented at the “Elektrophorese Forum “96” meeting of the German Electrophoresis Society, held at the Technical University Munich, October 23-25, 1996.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150180519
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  • 10
    Electronic Resource
    Electronic Resource
    Immuno-isolation of highly purified peroxisomes using magnetic beads and continuous immunomagnetic sorting (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1205-1210 
    Details
    ISSN: 0173-0835
    Keywords: Peroxisomes ; Immuno-isolation ; Free-flow magnetophoresis ; Magnetic beads ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Immuno-isolation is a powerful technique for the isolation of cells as well as subcellular organelle populations based on their antigenic properties. We have established a method for immuno-isolation of peroxisomes (PO) from both rat liver and the human hepatoblastoma cell line HepG2 using magnetic beads as solid support. A polyclonal antibody raised against the cytoplasmic C-terminal 10 amino acids of the rat 70 kDa peroxisomal membrane protein was covalently bound to magnetic beads (Dynabeads M-450). The coated beads were incubated with a light mitochondrial fraction and the organelle-bead complexes formed were separated by magnetic sorting in a free-flow system without pelleting the complexes during the isolation procedure. Scanning electron microscopy revealed decoration of beads with particles measuring 150-400 nm in diameter. The particles were identified as PO by catalase cytochemistry and biochemically by marker enzyme analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as well as immunoblotting for specific detection of peroxisomal matrix, core and membrane proteins. The functional significance of PO in man is emphasized by the existence of inherited diseases such as the Zellweger syndrome in which intact PO are lacking, but peroxisomal remnants called “ghosts” are observed instead. Peroxisomal disorders are usually studied using skin fibroblast cell lines derived from afflicted patients and immuno-magnetic separation may prove particularly useful for the investigation of such cultured cells and for further elucidation of the pathogenesis of fatal peroxisomal disorders.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190722
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