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  • 1
    Electronic Resource
    Electronic Resource
    A proton-translocating adenosine triphosphatase is associated with the peroxisomal membrane of yeasts (1987)
    Springer
    Archives of microbiology 147 (1987), S. 42-47 
    Details
    ISSN: 1432-072X
    Keywords: Hansenula polymorpha ; Yeast ; Peroxisomes ; Proton-translocating ATPase ; Cell fractionation ; Fluorescence quenching studies ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The association of an ATPase with the yeast peroxisomal membrane was established by both biochemical and cytochemical procedures. Peroxisomes were purified from protoplast homogenates of the methanol-grown yeast Hansenula polymorpha by differential and sucrose gradient centrifugation. Biochemical analysis revealed that ATPase activity was associated with the peroxisomal peak fractions which were identified on the basis of alcohol oxidase and catalase activity. The properties of this ATPase closely resembled those of the mitochondrial ATPase of this yeast. The enzyme was Mg2+-dependent, had a pH optimum of approximately 8.5 and was sensitive to N,N′-dicyclohexylcarbodiimide (DCCD), oligomycin and azide, but not to vanadate. A major difference was the apparent K m for ATP which was 4–6 mM for the peroxisomal ATPase compared to 0.6–0.9 mM for the mitochondrial enzyme. Cytochemical experiments indicated that the peroxisomal ATPase was associated with the membranes surrounding these organelles. After incubations with CeCl3 and ATP specific reaction products were localized on the peroxisomal membrane, both when unfixed isolated peroxisomes or formaldehyde-fixed protoplasts were used. This staining was strictly ATP-dependent; in controls performed i) in the absence of substrate, ii) in the presence of glycerol 2-phosphate instead of ATP, or iii) in the presence of DCCD, staining was invariably absent. Similar staining patterns were observed in subcellular fractions and protoplasts of Candida utilis and Trichosporon cutaneum X4, grown in the presence of ethanol/ethylamine or ethylamine, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00492903
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  • 2
    Electronic Resource
    Electronic Resource
    Proliferation and metabolic significance of peroxisomes in Candida boidinii during growth on d-alanine or oleic acid as the sole carbon source (1990)
    Springer
    Archives of microbiology 153 (1990), S. 485-489 
    Details
    ISSN: 1432-072X
    Keywords: Candida boidinii ; Yeast ; Peroxisomes ; β-Oxidation ; d-Amino acid oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have studied the induction of peroxisomes in the methylotrophic yeast Candida boidinii by d-alanine and oleic acid. The organism was able to utilize each of these compounds as the sole carbon source and grew with growth rates of μ=0.20 h-1 (on d-alanine) or μ=0.43 h-1 (on oleic acid). Growth was associated with the development of many peroxisomes in the cells. On d-alanine a cluster of tightly interwoven organelles was observed which made up 6.3% of the cytoplasmic volume and were characterized by the presence of d-amino acid oxidase and catalase. On oleic acid rounded to elongated peroxisomes were dominant which were scattered throughout the cytoplasm. These organelles contained increased levels of β-oxidation enzymes; their relative volume fraction amounted 12.8% of the cytoplasmic volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248431
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  • 3
    Electronic Resource
    Electronic Resource
    Permeability properties of peroxisomal membranes from yeasts (1990)
    Springer
    Archives of microbiology 153 (1990), S. 490-495 
    Details
    ISSN: 1432-072X
    Keywords: Hansenula polymorpha ; Candida boidinii ; Peroxisome ; Peroxisomal membrane ; Permeability ; Membrane fusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have studied the permeability properties of intact peroxisomes and purified peroxisomal membranes from two methylotrophic yeasts. After incorporation of sucrose and dextran in proteoliposomes composed of asolectin and peroxisomal membranes isolated from the yeasts Hansenula polymorpha and Candida boidinii a selective leakage of sucrose occurred indicating that the peroxisomal membranes were permeable to small molecules. Since the permeability of yeast peroxisomal membranes in vitro may be due to the isolation procedure employed, the osmotic stability of peroxisomes was tested during incubations of intact protoplasts in hypotonic media. Mild osmotic swelling of the protoplasts also resulted in swelling of the peroxisomes present in these cells but not in a release of their matrix proteins. The latter was only observed when the integrity of the cells was disturbed due to disruption of the cell membrane during further lowering of the concentration of the osmotic stabilizer. Stability tests with purified peroxisomes indicated that this leak of matrix proteins was not associated with the permeability to sucrose. Various attempts to mimic the in vivo situation and generate a proton motive force across the peroxisomal membranes in order to influence the permeability properties failed. Two different proton pumps were used for this purpose namely bacteriorhodopsin (BR) and reaction center-light-harvesting complex I (RCLHI complex). After introduction of BR into the membrane of intact peroxisomes generation of a pH-gradient was not or barely detectable. Since this pump readily generated a pH-gradient in pure liposomes, these results strengthened the initial observations on the leakiness of the peroxisomal membrane fragments. Generation of a membrane potential (Δψ) was also not observed when RCLHI complex was introduced into vesicles of purified peroxisomal membranes. The significance of the observed permeability of isolated yeast peroxisomal membranes to small molecules with respect to current and future in vitro import studies is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248432
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  • 4
    Electronic Resource
    Electronic Resource
    Assembly of amine oxidase and D-amino acid oxidase in the cytosol of peroxisome-deficient mutants of the yeast Hansenula polymorpha during growth of cells on glucose in the presence of primary amines or D-alanine as the sole nitrogen source (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 6 (1990), S. 501-509 
    Details
    ISSN: 0749-503X
    Keywords: Hansenula polymorpha ; peroxisomes ; peroxisome-deficient mutants ; amine oxidase ; D-amino acid oxidase ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have studied growth of two peroxisome-deficient mutant strains of Hansenula polymorpha on glucose in the presence of different organic nitrogen sources (methylamine, ethylamine and D-alanine), the metabolism of which is mediated by peroxisome-borne oxidases in wild-type (WT) cells. Both strains grew well on each of these substrates with growth rates comparable to WT cells. Growth on both methylamine and ethylamine was associated with enhanced levels of catalase and amine oxidase in the cells; in D-alanine-grown cells D-amino acid oxidase activity and increased. In WT cells of H-polymorpha the activities of these enzymes were confined to the peroxisomal matrix; however, in both peroxisome-deficient strains their activities were localized in the cytosol. Electron microscopy indicated that, dependent on the stage of growth, the enzymes may form large protein aggregates.The molecular masses of both amine oxidase and D-amino acid oxidase in the mutant strains were identical to their respective counterparts in WT cells, indicating that both proteins were correctly assembled and active in the cytosol.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320060607
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  • 5
    Electronic Resource
    Electronic Resource
    Occurrence of peroxisomal membrane proteins in methylotrophic yeasts grown under different conditions (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 6 (1990), S. 35-43 
    Details
    ISSN: 0749-503X
    Keywords: Hanseula polymorpha ; Candida boidinii ; peroxisomes ; peroxisomal membrane proteins ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have the substructure and polypeptide composition of the peroxisomal membranes in two methylotrophic yeasts in relation to different growth conditions. The results obtained that no significant ultrastructural differences existed between the membranes of variously grown cells.The presence of specific peroxisomal membrane proteins (PMPs) was studied biochemically. On sodium dodecyl sulphate-polyacrylamide gels of purified microbody membranes isolated from methanol-grown Hansenula polymorpha, prominent proteins bands were observed at 22, 31, 35, 42, 49 and 51 kD. These proteins were also present when the cells were grown in media containing ethanol and/or ethylamine. Apart from these, several other PMPs were specifically induced under these conditions, namely 24, 29, 37 and 62 kD proteins. The polypeptide composition of peroxisomal membranes from H. polymorpha was compared with that of another methylotroph. Candida biodinii. In the latter organism a specific PMP with a molecular weight of 23 kD was induced during growth on D-alanine instead of ammonium sulphate as the nitrogen source.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320060104
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  • 6
    Electronic Resource
    Electronic Resource
    The In Vitro permeability of yeast peroxisomal membranes is caused by a 31 kDa integral membrane protein (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 9 (1993), S. 733-742 
    Details
    ISSN: 0749-503X
    Keywords: Yeasts ; peroxisomes ; Hansenula polymorpha ; peroxisomal membrane ; permeability ; membrane protein ; ΔΨ measurements ; pore-forming protein ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A major 31 kDa integral peroxisomal membrane protein (PMP31) of Hansenula polymorpha was purified to homogeneity from isolated peroxisomal membranes by FPLC after solubilization by Triton X-100. Biochemical analysis indicated that this protein, which showed cross-reactivity with antibodies against the 31 kDa porin of the mitochondrial outer membrane of Saccharomyces cerevisiae, had pore-forming properties. Firstly, proteoliposomes composed of asolectin and purified PMP31 showed selective permeability, determined as the [14C]sucrose/[3H]dextran leakage ratios. Furthermore, the generation of a ΔΨ by potassium diffusion gradients was negatively affected by the presence of PMP31 in asolectin liposomes. A similar effect was observed in proteoliposomes containing purified cytochrome c oxidase as a ΔΨ generating system. Control experiments confirmed that the observed leakage is significant and introduced by the incorporation of PMP31 protein. Selective sucrose leakage was abolished in samples pretreated with glutaraldehyde; an identical effect of glutaraldehyde was, however, not observed for the membrane potential measurements.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320090707
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