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  • 1
    Electronic Resource
    Electronic Resource
    Vascularization, innervation, and ultrastructure of the endocrine cell types of stannius corpuscles in the teleost Gasterosteus aculeatus (1977)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 153 (1977), S. 225-243 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The blood circulation of the Stannius corpuscles, like that of the kidneys to which the corpuscles are attached, represents a portal system. The corpuscles receive blood from the dorsal caudal vein and from a vein coming from the hypaxial musculature. They are drained by veins which enter the caudal parts of the kidneys and therefore endocrine substances released by the corpuscles pass through the kidneys before they enter the general body circulation. The corpuscles are penetrated by sympathetic nerves coming from a small subvertebral ganglion. It is likely that these nerves innervate the muscular coat around the blood vessels. The muscular coat surrounding the renal blood vessels, the collecting tubules and part of the ureters, is innervated by nerves from the same ganglion. The secretory activity of the gland cells appears to be controlled by blood borne factors, because neither synaptic contacts with these cells, nor gap junctions among the cells, have been found in thin sections and freeze-etch replicas of the corpuscles.The corpuscles contain two cell types, both presumed to have endocrine function. Histochemical and ultrastructural data indicate that the gland cells produce glycoproteins. It is likely that the contents of the secretory granules are released by exocytosis. One cell type is structurally similar to the cells described in many other teleosts and thought to be engaged in the synthesis of a hypocalcemic hormone. The ultrastructure of the second cell type resembles cells described only in other migratory species: salmonids and eels. It may be involved in the control of monovalent ions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051530205
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  • 2
    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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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    Immunocytochemical demonstration of the peroxisomal ATPase of yeasts (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 6 (1990), S. 45-51 
    Details
    ISSN: 0749-503X
    Keywords: Yeasts ; peroxisomes ; ATPase ; freeze-fracturing immunocytochemistry ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The presence of an ATpase on yeast peroxisomal membranes was studied by immunological methods. Western blot analysis of purified peroxisomal membranes from several yeasts revealed distinct cross-reaction with specific antibodies against the F1-part or the β-subunit of the mitochondrial ATpase of Saccharomyces cerevisiae. This was not due to mitochondrial contamination as was demonstrated by analytical sucrose gradient centrifugation.Protein A-gold labelling carried out on Lowicryl-embedded methanol-grown Hansenula polymorpha using these antibodies did not result in significant staining. However, when organelles isolated from this yeast were successively incubated with antibodies and protein A-gold prior to embedding, specific labelling was observed on both the peroxisomal membrane and the membrane of damaged mitochondria but not on intact mitochondira. Specific labelling of the peroxisomal membrane was confirmed by freeze-fracture immunocytochemistry. In addition to the peroxisomal membrane, the mitochondrial membrane was also labelled in these experiments. Freeze-fracture immunocytochemistry was also successful for the localization of peroxisomal matrix proteins, e.g. alcohol oxidase and dihydroxyacetone synthase and of mitochondrial membrane proteins, e.g. cytochrome c oxidase.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320060105
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  • 5
    Electronic Resource
    Electronic Resource
    Liposome-mediated introduction of proteins into protoplasts of the yeast Hansenula polymorpha as a possible tool to study peroxisome biogenesis (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 6 (1990), S. 99-105 
    Details
    ISSN: 0749-503X
    Keywords: Hansenula polymorpha ; peroxisome biogenesis ; low pH-induced membrane fusion ; alcohol oxidase ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Low pH-induced fusion between liposomes and protoplasts of the yeast Hansenula polymorpha was demonstrated using a fluorescent assay and freeze-etch techniques. By this method foreign proteins could be introduced into the cytosol of the protoplast. For instance, after fusion of glucose oxidase-containing liposomes with protoplasts, activity of this enzyme was demonstrated cytochemically in the cytosol of the resulting protoplasts. Similar results were obtained when ferritin-containing liposomes were used. Incorporation of foreign proteins into liposomes was not a prerequisite for their introduction into the cytosol of protoplasts. In experiments where ferritin was added to protoplast suspensions together with empty liposomes, this protein was also delivered to the protoplast cytosol. However, in the absence of liposomes no uptake of proteins occurred.We tested the potential of this system in our studies on peroxisome biogenesis. Protoplasts of glucose-grown H. polymorpha remained stable for prolonged periods in osmotically stabilized cultivation media. Peroxisomes in such protoplasts were capable of protein import and assembly of matrix proteins as was demonstrated by the 20-fold increase in catalase activity after incubation with methanol or ethanol. However, mature alcohol oxidase purified from H. polymorpha introduced into protoplasts of glucose-grown cells of this organism was not targeted to peroxisomes as demonstrated with (immuno)cytochemical techniques. The enzyme remained present in the cytosol while its activity gradually decreased. Therefore mature alcohol oxidase probably does not expose the right topogenic signal(s) for recognition by its target organelle.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320060203
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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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  • 7
    Electronic Resource
    Electronic Resource
    Proliferation of microbodies in Saccharomyces cerevisiae (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 3 (1987), S. 77-84 
    Details
    ISSN: 0749-503X
    Keywords: Microbodies ; Saccharomyces cerevisiae ; oleic acid ; β-oxidation ; catalase ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The development of microbodies in the yeast Saccharomyces cerevisiae was studied in response to different conditions of growth. Various strains of S. cerevisiae were investigated, using cells from the exponential growth phase on glucose as an inocullum in all transfer experiments. Electron microscopy, including serial sectioning, revealed that these cells generally contained one to four small microbodies which were localized in the vicinity of the cell wall and characterized by the presence of catalase. Transfer of these glucose-grown cells into media supplemented with various compounds known to induce microbody proliferation in other yeasts - i.e. uric acid, alkylated amines, amino acids, C2-compounds such as ethanol or acetate, in the presence or absence of compounds that induce oxygen radical formation - did not result in a significant change in the number of microbody profiles observed. Marked microbody proliferation was, however, observed after a shift of cells into media containing oleic acid and was associated with the induction of activities of β-oxidation enzymes. In addition, catalase and isocitrate lyase were present in enhanced levels. Kinetic experiments suggested that these microbodies developed from those originally present in the inoculum cells. In thin sections up to 14 microbody profiles were occasionally observed, often present in small clusters. Their ultimate volume fraction amounted to 8-10% of the cytoplasmic volume.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320030204
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  • 8
    Electronic Resource
    Electronic Resource
    Selective inactivation of alcohol oxidase in two peroxisome-deficient mutants of the yeast Hansenula polymorpha (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 7 (1991), S. 813-821 
    Details
    ISSN: 0749-503X
    Keywords: Hansenula polymorpha ; alcohol oxidase ; peroxisome-deficient mutant ; selective inactivation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have studied selective inactivation of alcohol oxidase (AO) in two peroxisome-deficient (PER) mutants of the yeast Hansenula polymorpha. In these mutants high activities of cytosolic AO are induced by different growth conditions. At enhanced expression rates AO is arranged in large crystalloids in the cytosol, whereas smaller crystalloids are often observed inside the nucleus. Transfer of cells of the PER mutant 125-2E, which completely lacks peroxisomes, to glucose-excess conditions did not lead to degradative inactivation of AO and catalase as observed in wild-type (WT) cells used as a control. The gradual decrease in enzyme activities in the PER mutant could be accounted for by dilution of existing enzyme into newly formed cells as a result of growth. Morphologically, degradation of the cytosolic crystalloids was also not observed. Similar results were obtained with a second PER mutant (strain 124-2D), impaired in the import of peroxisomal matrix proteins. This mutant is characterized by the presence of small peroxisomes and large cytosolic AO crystalloids. Upon a shift of cells to glucose-excess conditions only part of the small peroxisomes present in these cells were degraded by mechanisms similar to those observed in WT cells placed under identical conditions. These results indicate that degradative inactivation of AO in H. polymorpha is strictly dependent on the localization of the enzyme inside peroxisomes and furthermore suggests that the mechanisms triggering this process are not directed against AO protein, but instead, to the membrane surrounding the organelle. Transfer of cells to methanolor ethanol-containing media both resulted in modification inactivation of AO. Under these conditions also the AO crystalloids remained unaffected by incubation in the new environment.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/yea.320070806
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