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  • 1
    Electronic Resource
    Electronic Resource
    Phylogenetic relationship of ubiquitin repeats in the polyubiquitin gene from the marine sponge Geodia cydonium (1994)
    Springer
    Journal of molecular evolution 39 (1994), S. 369-377 
    Details
    ISSN: 1432-1432
    Keywords: Ubiquitin ; Phylogeny ; Sponges ; Geodia cydonium ; Evolution strategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ubiquitin is a 76-residue protein which is highly conserved among eukaryotes. Sponge (Porifera) ubiquitin, isolated from Geodia cydonium, is encoded by a gene (termed GCUBI) with six repeats, GCUBI-1 to GCUBI-6. All repeat units encode the same protein (with one exception: GCUBI-4 encodes ubiquitin with a change of Leu to Val at position 71). On the nt level the sequences of the six repeats differ considerably. All changes (except in GCUBI-4) are silent substitutions, which do not affect the protein structure. However, there is one major difference between the repeats: Codons from both codon families (TCN and AGPy) are simultaneously used for the serine at position 65. Using this characteristic the repeats were divided into two groups: Group I: GCUBI-1,3 (TCT codon) and GCUBI-5 (TCC); Group II: GCUBI-2,4,6 (AGC codon). Mutational analysis suggests that the sponge polyubiquitin gene evolved from an ancestral monoubiquitin gene by gene duplication and successive tandem duplications. The ancestral monoubiquitin gene most probably coded for threonine (ACC) at position 65. The first event, duplication of the monoubiquitin gene, happened some 110 million years ago. Since sponges from the genus Geodia are known from the Cretaceous (145 million) to recent time, it is very likely that all events in the evolution of polyubiquitin gene occurred in the same genus. Alignment data of the “consensus” ubiquitin nt sequences of different animals (man to protozoa) reflect very well the established phylogenetic relationships of the chosen organisms and show that the sponge ubiquitin gene branched off first from the multicellular organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160269
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of expression of prion protein in uninfected and scrapie-infected N2a mouse neuroblastoma cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 11 (1993), S. 1-11 
    Details
    ISSN: 0263-6484
    Keywords: Prion protein ; prion gene expression ; scrapie ; N2a cells ; mouse neuroblastoma cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The scrapie prion protein, PrPSc, is formed from its isoform, the cellular PrPc. There is evidence available indicating that PrPSc is necessary component of the infectious prion particle to cause a series of transmissible spongiform encephalopathies. We have used immunocytochemistry and RNA blotting techniques to investigate if infection with prions results in an increased PrP gene expression. For the experiments we used N2a cells which had been infected with prions (ScN2a cells). We demonstrated by confocal laser scanning microscopy that PrP-protein was present in the nucleus (predominantly in the nucleoli) of ScN2a cells. Analysis of the PrP-mRNA levels both in N2a- and in ScN2a cells using cDNA encoding PrPc revealed no marked alteration of the mRNA steady state level between the two cell strains. Likewise, in run-off experiments no changes in either PrP-specific transcription or in general transcriptional activity were found. The half-life of PrP-mRNA was found to be identical in both cell strains (7 h). Taken together, these results show that PrPSc and /or PrPc is present in the nucleus (nucleoli) of ScN2a cells but does not display and effect on the expression of the PrP gene.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290110102
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  • 3
    Electronic Resource
    Electronic Resource
    Action of the antileukemic and anti-HTLV-III (anti-HIV) agent avarol on the levels of superoxide dismutases and glutathione peroxidase activities in L5178y mouse lymphoma cellsThis investigation was supported in part by a grant from the Deutsche Krebshilfe e. V. (W 31/84/Mü 1) and by a grant from the Bundesministerium für Forschung und Technologie under the co-ordination of the Internationales Büro GKSS, Geesthacht. (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 6 (1988), S. 123-129 
    Details
    ISSN: 0263-6484
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The antileukemic and anti-HTLV-III (anti-HIV) agent avarol, a sesquiterpenoid hydroquinone, was determined to be converted into its corresponding quinone derivative avarone via the semiquinone free radical. Its g-value was 2·0047; after hyperfine splitting the energy levels revealed 16 isotropic Hfs. The redox reaction products were identified at the pH values 4·0, 7·0 and 12·0 and the overall reaction pathways were formulated. In vivo experiments with L5178y mouse lymphoma cells in the ascites of mice revealed that the cytostatic potencies of avarol and avarone cannot be augmented by lowering the pH value. Incubation studies with L5178y cells in vitro showed that the intracellular levels of superoxide dismutases (SODases) and of glutathione (GSH) peroxidase activities significantly change after avarol administration. While both the Mn-SODase and the Cu/Zn-SODase activities dropped significantly, the GSH peroxidase activity increased inversely. From these experiments we assume that the anti-tumour and the antiviral effects of avarol/avarone may be due to an increase, induced by the drug, of the intracellular concentrations of superoxide radicals.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cbf.290060207
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