ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0983
    Keywords: psbA ; Cyanelle ; Cyanophora paradoxa ; Evolution ; Sequence analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The psbA gene is part of the reaction center of photosystem II in cyanobacteria and the plastids of higher plants. Its primary sequence is highly conserved among all species investigated so far and its sequence shows homologies with the L and M subunits of the reaction center of photosynthetic bacteria. We have analyzed the psbA homolog from a eukaryotic alga, Cyanophora paradoxa, where the gene is encoded on cyanelle DNA. These cyanelles are surrounded by a murein sacculus and resemble cyanobacteria in many other characteristics, although they are genuine organelles that functionally replace plastids. Analysis of the gene revealed a psbA protein identical in length (360 codons) with the cyanobacterial counterpart. The overall sequence identity is, however, more pronounced between cyanelle psbA and the shorter (353 amino acids) psbA product found in higher plants. These data strongly support the postulated bridge position of cyanelles between chloroplasts and free-living cyanobacteria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0983
    Keywords: Cyanelle DNA ; Strain differences ; Cyanophora paradoxa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cyanelle DNA from two different strains of Cyanophora paradoxa (strain LB555UTEX and strain 1555) was investigated. The cyanelle DNA from both strains showed a buoyant density in neutral CsCI gradients of 1.692 g/cm3. The total molecular weight, as judged by restriction endonuclease analysis, of the two cyanelle DNAs differed. In strain LB555UTEX the size of the cyanelle DNA was equivalent to 127 ± 1 kb whereas in strain 1555 a size of 138 ± 1 kb was consistently found. The sizes of individual DNA fragments and the number of recognition sites for a particular restriction endonuclease appeared largely unrelated. A high amount of cross hybridization, as judged by reciprocal heterologous DNA hybridizations, however indicated a high degree of sequence homology between the two cyanelle DNAs. Under comparable conditions, cyanelle DNA hybridized nearly exclusively with the dG+dC-rich rRNA transcription units from plastid DNAs. Up to now conserved restriction endonuclease recognition sites between the two cyanelle DNAs were only observed within the cyanelle rRNA genes which are present twice on both cyanelle DNAs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0983
    Keywords: Cyanophora paradoxa ; Kies-strain ; Cyanelle DNA ; Physical and gene mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A restriction map of the cyanelle DNA from a different isolate of Cyanophora paradoxa (Kies-strain) was established. The positions of 18 protein genes and the rRNA genes have been located and compared to the positions of these genes from the first isolate of C. paradoxa (Pringsheim-strain). The gene arrangement is absolutely conserved in both cyanelle DNAs. The differences in size (ca. 9 kb) and the unrelatedness in the restriction patterns could be explained by numerous small insertions into intergenic regions of the cyanelle chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-5028
    Keywords: cyanelle DNA ; Cyanophora paradoxa ; tRNAala gene ; tRNAile gene ; 3′-16S-rDNA ; 5′-23S-rDNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 287-bp spacer and the flanking 3′-end of the 16S- and 5′-end of the 23S-rRNA genes of the cyanelles from Cyanophora paradoxa have been sequenced and compared with the corresponding regions of cyanobacteria and chloroplasts. The spacer contains the uninterrupted genes for tRNAile and tRNAala. All coding regions show high homology to their prokaryotic counterparts. At the 3′-end of the 16S-rDNA a CCTCCTTT sequence has been identified which is complementary to putative ribosome binding sites observed immediately upstream of the coding region of cyanelle protein genes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-5028
    Keywords: cyanelles ; Cyanophora paradoxa ; peptidoglycan ; petH ; pre-ferredoxin-NADP+ reductase ; protein import
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone for pre-ferredoxin-NADP+ reductase (FNR) was obtained by screening a Cyanophora paradoxa expression library with antibodies specific for cyanelle FNR. The 1.4 kb transcript was derived from a single-copy gene. The precursor (41 kDa) and mature forms (34 kDa) of FNR were identified by western blotting of in vitro translation products and cyanelle extracts, respectively. The derived amino acid sequence of the mature form was corroborated by data from N-terminal protein sequencing and yielded identity scores from 58% to 62% upon comparison with cyanobacterial FNRs. Sequence conservation seemed to be even more pronounced in comparison with enzymes from higher plants, but using the neighbor joining method the C. paradoxa sequence was clearly positioned between the prokaryotic and eukaryotic sequences. The transit peptide of 65 or 66 amino acids appeared to be totally unrelated to those from spinach, pea and ice plant but showed overall characteristics of stroma-targeting peptides.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 224 (1990), S. 222-231 
    ISSN: 1617-4623
    Keywords: Cyanophora paradoxa ; Cyanelle ; Ribosomal protein gene ; S10-spc operon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Cyanophora paradoxa photosynthetic organelles termed cyanelles perform the functions of chloroplasts in higher plants, while the structural and biochemical characteristics of the cyanelle are essentially cyanobacterial. Our interest in studying the evolutionary relationship between cyanelles and chloroplasts led us to focus on cyanelle-encoded genes of the translational apparatus, specifically genes equivalent to those of the bacterial S10 and spc operons. The structure of a large ribosomal protein gene cluster from cyanelle DNA was characterized and compared with that from plastids and bacteria. Sequences of the following cyanelle genes encompassing 4.8 kb are reported here: 5′-rpl22-rps3-rpl16-rps17-rpl14-rpl5-rps8-rpl6-rpl18-rps5-3′. Cyanelles contain five more ribosomal protein genes than do higher plant chloroplasts and four more genes than Euglena gracilis plastids in the S10/spc region of this gene cluster. The gene encoding rpl36 is absent, in contrast to the case in other plastid DNAs. These genes, including the previously characterized genes rpl3, rpl2 and rps19, are transcribed as a primary transcript of ∼7500 nucleotides. The occurrence of transcripts smaller than this presumptive primary transcript suggests that it is processed into defined segments. Transcription terminates 3′ of rps5 where a 40 by hairpin with one mismatch (−42.2 kcal) may be folded. Immediately downstream of rps5 an open reading frame, ORF492, is contained on a separate transcript. A comparison of gene content, operon structure and deduced amino acid sequence of the genes in the S10 and spc operons from different organisms supports the notion that cyanelles are intermediary between known plastids and cyanobacteria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 164 (1995), S. 85-92 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth-regulated vimentin gene contains a functional double AP-1 binding site formed by two nearly perfect inverted repeats. We present evidence for down-regulation of vimentin expression by the retinoic acid receptor (RAR) in two mesodermally derived cell types. By mutation analysis we prove that the double consensus element is responsible for this negative regulation. From in vitro protein-DNA interaction studies we conclude that AP-1 binding is inhibited at RAR amounts required for occupation of the cognate RAR binding site in nuclear extracts from 3T3 cells and differentiated embryonal carcinoma cells. Furthermore, we show that, unlike in other cases, trans-activation of the vimentin AP-1 enhancer element can occur in undifferentiated embryonal carcinoma cells, despite the low amount of Jun and Fos proteins present in these cells. Here, however, down-regulation by retinoic acid cannot be detected. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 18 (1996), S. 379-389 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lysosomes are the site of degradation of obsolete intracellular material during autophagy and of extracellular macromolecules following endocytosis and phagocytosis. The membrane of lysosomes and late endosomes is enriched in highly glycosylated transmembrane proteins of largely unknown function. Significant progress has been made in recent years towards elucidating the pathways by which these lysosomal membrane proteins are delivered to late endosomes and lysosomes. While some lysosomal membrane proteins follow the constitutive secretory pathway and reach lysosomes indirectly via the cell surface and endocytosis, others exit the trans-Golgi network in clathrin-coated vesicles for direct delivery to endosomes and lysosomes. Sorting from the Golgi or the plasma membrane into the endosomal system is mediated by signals encoded by the short cytosolic domain of these proteins. This review will discuss the role of lysosomal membrane proteins in the biogenesis of the late endosomal and lysosomal membranes, with particular emphasis on the structural features and molecular mechanisms underlying the intracellular trafficking of these proteins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 59 (1995), S. 117-125 
    ISSN: 0730-2312
    Keywords: AIDS ; anticarcinogen ; antiviral ; chemoprevention ; dithiolethiones ; glutathione ; reverse transcriptase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Glutathione (GSH) levels are markedly depleted in patients infected with human immunodeficiency virus type 1 (HIV-1) and supplementation of media with high concentrations (5-20 mM) of low-molecular weight thiols prevents HIV-1 replication in cultured cells. We were intrigued whether chemo-preventive enzyme inducers might represent a more pharmacologically feasible method to inhibit HIV-1 replication since these compounds elevate intracellular concentrations of GSH at nontoxic doses in vivo. After establishing that all inducers surveyed were able to elevate GSH levels in human T-cell and monocytoid cell lines, we were surprised to find that olitpraz (5-pyrazinyl-4-methyl-1,2-dithiole-3-thione) was uniquely able to inhibit HIV-1 replication (IC50 = 5-15 μM). Oltipraz and other antiviral 1,2-dithiole-3-thiones (DTTs) appear to inhibit acute HIV-1 replication by inactivating reverse transcriptase (RT). However, among DTTs that inhibit HIV-1 replication in acutely infected cells, only oltipraz was able to inhibit HIV-1 replication in a chronic infection model. Thus, in addition to inactivating RT, oltipraz appears to have an additional antiviral mechanism distal to viral integration. Our laboratories are attempting to determine the mechanism by which oltipraz inhibits HIV-1 replication in chronically infected cells; we are also attempting to determine the bioorganic mechanism for the inactivation of RT. Since the covalent modification of schistosomal protein and transcription factor(s) are thought to be responsible for the antiparasitic and chemopreventive activities of DTTs, respectively, our studies should be relevant to understanding the diverse medicinal properties of DTTs. Oltipraz, an antischistosomal drug undergoing clinical evaluation as an anticarcinogen, inhibits HIV-1 replication at concentrations achievable in human serum. It is intriguing to consider oltipraz as a therapeutic agent not only for its antiretroviral activity, but also for the prevention of HIV-1 associated neoplasms.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0730-2312
    Keywords: aflatoxin B1 ; aflatoxin albumin adducts ; biomarkers ; enzyme induction ; glutathione S-transferases ; hepatocellular carcinoma ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Oltipraz has been used clinically in many regions of the world as an antischistosomal agent and is an effective inhibitor of aflatoxin hepatocarcinogenesis in rats. This chemopreventive action of oltipraz results primarily from an altered balance in aflatoxin metabolic activation and detoxication. In 1995, a randomized, placebo-controlled, double-blind intervention was conducted in residents of Qidong, People's Republic of China, who are at high risk for exposure to aflatoxin and development of hepatocellular carcinoma. The major study objectives were to define a dose and schedule for oltipraz that would reduce levels of aflatoxin biomarkers in biofluids of the participants, and to further characterize dose-limiting side effects. Two hundred thirty-four healthy eligible individuals, including those infected with HBV, were randomized to receive either 125 mg oltipraz daily, 500 mg oltipraz weekly, or placebo. Blood and urine specimens were collected to monitor potential toxicities and evaluate biomarkers over the 8-week intervention and subsequent 8-week follow-up periods. Overall, compliance in the intervention was excellent; approximately 85% of the participants completed the study. Objective evaluation of adverse events was greatly facilitated by inclusion of a placebo arm in the study design. A syndrome involving numbness, tingling, and pain in the fingertips was the only event that occurred more frequently among the active groups (18 and 14% of the daily 125 mg and weekly 500 mg arms, respectively) compared to placebo (3%). These symptoms were reversible and could be relieved with non-steroidal antiinflammatory agents. A more complete understanding of the chemopreventive utility of oltipraz awaits completion of an assessment of the efficacy of oltipraz in modulating levels of aflatoxin biomarkers. J. Cell. Biochem. Suppls. 28/29:166-173. © 1998 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...