TY - JOUR
A1 - Arends, H.
A1 - Sebald, Walter
T1 - Nucleotide sequence of the cloned mRNA and gene of the ADP/ATP carrier from Neurospora crassa
N2 - A cDNA complementary to the mRNA of the ADPIATP carrier from Neurospora crassa was identified among ordered cDNA clones by hybridizing total polyadenylated RNA to pools of 96 cDNA recombinant plasmids and subsequent cellfree translation of hybridization-selected mRNA. Further carrier cDNAs were found by colony fdter hybridization at a frequency of 0.2-0.3%. The gene of the carrier was cloned and isolated on a 4.6-kbp EcoRl fragment of total Neurospora DNA, and the start of the mRNA was determined by Sl nuclease mapping. From the nucleotide sequence of the cDNA and the genomic DNA, the primary structure of the gene, of the mRNA and of the ADP I ATP carrier protein could be deduced. The gene occurs in a single copy in the genome and related genes are absent. It contains two short introns, and a pyrimidine-rieb promoter region. The mRNA has a 46-bp 5 1 end and a 219-bp 3 1 end. There is an open reading frame coding for the 313 amino acid residues of the Neurospora carrier protein. The amino acid sequence is homologous in 148 positions with the established primary structure of the beef heart carrier.
KW - Biochemie
KW - mitochondrial ADP
KW - ATP carrier
KW - Neurospora crassa
KW - mRNA and gene
KW - nucleotide sequence
KW - hybrid-selected translation
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62684
ER -
TY - JOUR
A1 - Velours, J.
A1 - Esparza, M.
A1 - Hoppe, J.
A1 - Sebald, Walter
A1 - Guerin, B.
T1 - Amino acid sequence of a new mitochondrially synthesized proteolipid of the ATP synthase of Saccharomyces cerevisiae
N2 - The purification and the amino acid sequence of a proteolipid translated on ribosomes in yeast mitochondria is reported. This protein, which is a subunit of the A TP synthase, was purified by extraction with chloroform/methanol (2/1) and subsequent chromatography on phosphocellulose and reverse phase h.p.l.c. A mol. wt. of 5500 was estimated by chromatography on Bio-Gel P-30 in 8011/o fonnie acid. The complete amino acid sequence of this protein was determined by automated solid phase Edman degradation of the whole protein and of fragments obtained after cleavage with cyanogen bromide. The sequence analysis indicates a length of 48 amino acid residues. The calculated mol. wt. of 5870 corresponds to the value found by gel chromatography. This polypeptide contains three basic residues and no negatively charged side chain. The three basic residues are clustered at the C terminus. The primary structure of this protein is in full agreement with the predicted amino acid sequence of the putative polypeptide encoded by the mitochondrial aap1 gene recently discovered in Saccharomyces cerevisiae. Moreover, this protein shows 5011/o homology with the amino acid sequence of a putative polypeptide encoded by an unidentified reading frame also discovered near the mitochondrial ATPase subunit 6 genein Aspergillus nidulans.
KW - Biochemie
KW - ATP synthase
KW - mitochondrially translated
KW - proteolipid
KW - sequence subunit
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62695
ER -
TY - JOUR
A1 - Schmidt, B.
A1 - Wachter, E.
A1 - Sebald, Walter
A1 - Neupert, W.
T1 - Processing peptidase of Neurospora mitochondria. Two-step cleavage of imported ATPase subunit 9
N2 - Subunit 9 (dicyclohexylcarbodümide binding protein, 'proteolipid') of the mitochondrial F 1F0-ATPase is a nuclearly coded protein in Neurospora crassa. lt is synthesized on free cytoplasmic ribosomes as a larger precursor with an NH2-terminal peptide extension. The peptide extension is cleaved ofT after transport of the protein into the mitochondria. A processing activity referred to as processing peptidase that cleaves the precursor to subunit 9 and other mitochondrial proteins is described and characterized using a cell-free system. Precursor synthesized in vitro was incubated with extracts of mitochondria. Processing peptidase required Mn2 + for its activity. Localization studies suggested that it is a soluble component of the mitochondrial matrix. The precursor was cleaved in two sequential steps via an intermediate-sized polypeptide. The intermediate form in the processing of subunit 9 was also seen in vivo and upon import of the precursor into isolated mitochondria in vitro. The two dcavage sites in the precursor molecule were determined. The data indicate that: {a) the correct NH2-terminus of the mature protein was generated, (b) the NH2-terminal amino acid of the intermediate-sized polypeptide is isoleueine in position -31. The cleavage sites show similarity ofprimary structure. It is concluded that processing peptidase removes the peptide extension from the precursor to subunit 9 (and probably other precursors) after translocation of these polypeptides (or the NHrterminal part of these polypeptides) into the matrix space of mitochondria.
KW - Biochemie
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62674
ER -
TY - JOUR
A1 - Schartl, Manfred
A1 - Barnekow, A.
T1 - Differential expression of the cellular src gene during vertebrate development
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61893
ER -
TY - JOUR
A1 - Schartl, Manfred
A1 - Barnekow, A.
T1 - Cellular src gene product detected in the freshwater sponge Spongilla lacustris
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61904
ER -
TY - JOUR
A1 - Riehl, R.
A1 - Schartl, Manfred
T1 - A Transmission Electron Microscopical and Freeze-Etch Study of Malignant-Melanoma in Fish
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61916
ER -
TY - JOUR
A1 - Riehl, R.
A1 - Schartl, Manfred
A1 - Kollinger, G.
T1 - Comparative studies on the ultrastructure of malignant melanoma in fish and human by freeze-etching and transmission electron microscopy
N2 - Malignant melanomas (MM) in the fish Xiphophorus and in humans were studied both by transmission electron microscopy (TEM) and freeze-etching (FE). In both fish and human melanomas the cells show interdigitations of the,plasma membranes. The nuclei are large and lobulated and have many nuclear pores. Melanosomes are abundant and melanosome complexes ("compound melanosomes") occur regularly. Pinocytotic vesicles could be demonstrated in fish and human melanomas showing iocal differences in frequency and distribution patterns in the tumor. lntercellular junctions are lacking in MM cells from fish and humans. The FE technique showed considerable advantages in demonstrating membrane-surface peculiarities such as nuclear pores or pinocytotic vesicles. The FE replicas of fish melanomas are like those of humans. These findings may support the hypothesis that melanoma in fish and humans reflect the same biological phenomenon.
KW - Physiologische Chemie
KW - Malignant melanoma
KW - Fish
KW - Human
KW - Freeze-etching
KW - Transmission electron microscopy
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61920
ER -
TY - JOUR
A1 - Scheer, Ulrich
A1 - Schmidt-Zachmann, Marion S.
A1 - Hügle, Barbara
A1 - Franke, Werner W.
T1 - Identification and localization of a novel nucleolar protein of a high molecular weight by a monoclonal antibody
N2 - A monoclonal murine antibody (No-I 14) is described which reacts specifically with a polypeptide of molecular weight (M,) 180000 present in low-speed nuclear pellets from oocytes and somatic cells of Xenopus laevis and X. borealis and in isolated amplified nucleoli. Two-dimensional gel electrophoresis has revealed the acidic nature of this polypeptide (isoelectric at pH of ca 4.2 in the presence of 9.5 M urea). A relatively large proportion of the protein is extracted at elevated ionic strength( i.e., at 0.4-0.5 M alkali salt) in a form sedimenting at approx. 7-8S , compatible with a monomeric state. It is also extracted by digestion with RNase but not with DNase. In immunofluorescence microscopy, antibody No-114 stains intensely nucleoli of oocytes and all somatic cells examined , including the residual nucleolar structure of Xenopus erythrocytes which are transcriptionally inactive. During mitosis the antigen does not remain associated with the nucleolar organizer regions (NOR) of chromosomes but is released and dispersed over the cytoplasm until telophase when it re-associates with the reforming interphase nucleoli. At higher resolution the immunofluorescent region is often resolved into a number of distinct subnucleolar components of varied size and shape. Immunoelectron microscopy using colloidal gold-coupled secondary antibodies reveals that the M, 180000 protein is confined to the dense fibrillar component of the nucleolus. This conclusion is also supported by its localization in the fibrillar part of segregated nucleoli of cells treated with actinomycin D. We conclude that nucleoli contain a prominent protein of M, 180000 which contributes to the general structure of the dense fibrillar component of the interphase nucleolus , independent of its specific transcriptional activity.
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39786
ER -
TY - JOUR
A1 - Scheer, Ulrich
A1 - Hinssen, Horst
A1 - Franke, Werner W.
A1 - Jockusch, Brigitte M.
T1 - Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes
N2 - Nuclei of amphibian oocytes contain large amounts of actin, mostly in unpolymerized or short-polymer form. When antibodies to actin or actin-binding proteins (fragmin and the actin modulator from mammalian smooth muscle) are injected into nuclei of living oocytes of Pleurodeles waltlii, transcription of the lampbrush chromosomes, but not of the rRNA genes, is inhibited. When transcription is repressed by drugs or RNA is digested by microinjection of RNAase into oocyte nuclei, an extensive meshwork of actin filament bundles is seen in association with the isolated lampbrush chromosomes. These observations indicate a close relationship between the state of nuclear actin and transcriptional activity and suggest that nuclear actin may be involved in transcriptional events concerning protein-coding genes.
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39706
ER -
TY - JOUR
A1 - Scheer, Ulrich
A1 - Hügle, Barbara
A1 - Hazan, Rachel
A1 - Rose, Kathleen M.
T1 - Drug-induced dispersal of transcribed rRNA genes and transcriptional products: Immunolocalization and silver staining of different nucleolar components in rat cells treated with 5,6-dichloro-1-Beta-D-ribofuranosylbenzimidazole
N2 - Upon incubation of cultured rat cells with the adenosine analogue 5,6-dichloro-l-β- D-ribofuranosylbenzimidazole (DRB), nucleoli reversibly dissociate into their substructures, disperse throughout the nuclear interior, and form nucleolar "necklaces". We have used this experimental system, which does not inhibit transcription of the rRNA genes, to study by immunocytochemistry the distribution of active rRNA genes and their transcriptional products during nucleolar dispersal and recovery to normal morphology. Antibodies to RNA polymerase I allow detection of template-engaged polymerase, and monoclonal antibodies to a ribosomal protein (S 1) of the small ribosomal subunit permit localization of nucleolar preribosomal particles. The results show that, under the action of DRB transcribed rRNA, genes spread throughout the nucleoplasm and finally appear in the form of several rows, each containing several (up to 30) granules positive for RNA polymerase land argyrophilic proteins. Nucleolar material containing preribosomal particles also appears in granular structures spread over the nucleoplasm but its distribution is distinct from that of rRNA gene-containing granules. We conclude that, although transcriptional units and preribosomal particles are both redistributed in response to DRB, these entities retain their individuality as functionally defined subunits. We further propose that each RNA polymerase-positive granular unit represents a single transcription unit and that each continuous array of granules ("string of nucleolar beads") reflects the linear distribution of rRNA genes along a nucleolar organizer region. Based on the total number of polymerase I-positive granules we estimate that a minimum of 60 rRNA genes are active during interphase of DRB-treated rat cells.
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33216
ER -
TY - JOUR
A1 - Linsenmair, Karl Eduard
T1 - Comparative studies on the social behaviour of the desert isopod Hemilepistus reaumuri and of a Porcellio species
N2 - Behavioural adaptations have made the desert isopod Hemilepistus reaumuri the most successful herbivore and detritivore of the macrofauna of many arid areas in North Africa and Asia Minor. For survival and reproduction Hemilepistus is dependent on burrows. New burrows can only be dug during spring. With the time-consuming digging of a burrow, Hemilepistus has only made the first step towards solving its ecological problems. The burrows are vital and have to be continuously defended against competitors. This requirement is met by co-operation of individuals within the framework of a highly developed social behaviour. In spring adults form monogamous pairs in which partners recognize each other individually and later form, with their progeny, strictly closed family communities. Hemilepistus is compared with a Porcellio' sp. which has developed, convergently, a social behaviour which resembles that of Hemilepistus in many respects, but differs essentially in some aspects, partly reflecting differences in ecological requirements. This and a few other Porcellio species demonstrate some possible steps in the evolution of the social behaviour of Hemilepistus. The female Hemilepistus is-in contrast to Porcellio sp. - semelparous and the selective advantages of monogamy in its environment are not difficult to recognize. This chapter discusses how this mating system could have evolved and especially why monogamous behaviour is also the best method for the Hemilepistus male to maximize its reproductive success. The cohesion of pairs and of family communities in Hemilepistus is based on a highly developed chemical communication system. Individual- and family-specific badges owe their specificity to genetically determined discriminating substances. The nature of the badges raises a series of questions: e.g. since alien badges release aggression, how do parents avoid cannibalizing their young? Similar problems arise from the fact that family badges are mixtures of chemical compounds of very low volatility with the consequence that they can only be transferred by direct contact and that during moulting all substances are lost which an individual does not produce itself. It is shown that in solving these problems inhibiting properties (presumably substances) and learning play a dominant role.
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30846
ER -
TY - JOUR
A1 - Anders, F.
A1 - Schartl., Manfred
A1 - Barnekow, A.
A1 - Anders, A.
T1 - Xiphophorus as an in vivo model for studies on normal and defective control of oncogenes
N2 - The Xiphophorus tumor system has provided the opportunity to reduce the enormous complexity of cancer etiology to a few biological elements basically involved in neoplasia. The development of a tumor requires an oncogene which, after impairment, deletion, or elimination of its regulatory genes is permitted to mediate neoplastic transformation. Emphasis is being placed today in cancer research on the actual oncogenes themselves, but, in our opinion, the most important genes involved in neoplasia are these regulatory genes. However, although detected by c1assical genetics in the Xiphophorus system, th ese genes are not at present open to a more fin ely detailed molecular biological analysis. Their actual mode of action is therefore still far from being understood.
KW - Xiphophorus
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80721
ER -
TY - JOUR
A1 - Meyer, Manfred K.
A1 - Schartl, Manfred
T1 - Pseudotropheus (Maylandia) hajomaylandi n. sp., a new taxon from Lake Malawi
T1 - Pseudotropheus (Maylandia) hajomaylandi n. sp. un nouveau taxon du Lac Malawi
N2 - Pseudotropheus hajomaylandi (loc. typ. Isle of Chisumulu, Lake Malawi) is described as a new species. It is compared with Ps. aurora, Ps. greshakei, Ps. livingstonii, Ps. lombardoi, and Ps. zebra. All these taxa, including Ps. hajomaylandi and Ps. heteropictus, are classified in the subgenus Maylandia.
KW - Buntbarsche
KW - Njassasee
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-70989
ER -
TY - JOUR
A1 - Franke, Werner W.
A1 - Scheer, Ulrich
A1 - Zentgraf, Hanswalter
T1 - Organization of transcriptionally active and inactive chromatin
N2 - No abstract available
KW - Deutschland
KW - Gefäßpflanzen
KW - Verzeichnis
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-40588
ER -
TY - JOUR
A1 - Hoppe, J.
A1 - Sebald, Walter
T1 - The proton conducting F0-part of bacterial ATP synthases
N2 - No abstract available
KW - Biologie
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-82019
ER -
TY - JOUR
A1 - Sebald, Walter
A1 - Arends, Hermann
A1 - McCarthy, John E. G.
T1 - Isolation and manipulation of genes coding for energy-transducing enzymes from Neurospora crassa and Escherichia coli
N2 - No abstract available.
KW - Escherichia coli
KW - Neurospora crassa
Y1 - 1984
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86768
ER -
TY - JOUR
A1 - Harnisch, U.
A1 - Weiss, H.
A1 - Sebald, Walter
T1 - The primary structure of the iron-sulfur subunit of ubiquinol-cytochrome c reductase from Neurospora, determined by cDNA and gene sequencing
N2 - No abstract available
KW - Biochemie
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62631
ER -
TY - JOUR
A1 - Gabellini, N.
A1 - Harnisch, U.
A1 - McCarthy, J. E.
A1 - Hauska, G.
A1 - Sebald, Walter
T1 - Cloning and expression of the fbc operon encoding the FeS protein, cytochrome b and cytochrome c\(_1\) from the Rhodopseudomonas sphaeroides b/c\(_1\) complex
N2 - The gene for the FeS protein of the Rhodopseudomonas sphaeroides b/c1 complex was identified by means of crosshybridization with a segment of the gene encoding the corresponding FeS protein of Neurospora crassa. Plasmids (pRSF1-14) containing the cross-hybridizing region, covering in total 13.5 kb of chromosomal DNA, were expressed in vitro in a homologous system. One RSF plasmid directed the synthesis of all three main polypeptides of the R. sphaeroides blc1 complex: the FeS protein, cytochrome b and cytochrome c1• The FeS protein and cytochrome c1 were apparently synthesized as precursor fonns. None of the pRSF plasmids directed the synthesis of the 10-kd polypeptide found in b/c1 complex preparations. Partial sequencing of the cloned region was performed. Several sites of strong homology between R. sphaeroides and eukaryotic polypeptides of the b/c1 complex were identified. The genes encode the three b/c1 polypeptides in the order: (5') FeS protein, cytochrome b, cytochrome c1• The three genes are transcribed to give a polycistronic mRNA of 2.9 kb. This transcriptional unit has been designated the jbc operon; its coding capacity corresponds to the size of the polycistronic mRNA assuming that only the genes for the FeS protein (jbcF), cytochrome b (jbcß) and cytochrome c1 (jbcC) are present. This could indicate that these three subunits constitute the minimal catalytic unit of the b/c1 complex from photosynthetic membranes.
KW - Biochemie
KW - R. sphaeroidesl
KW - b/c1 complex
KW - gene
KW - cloning
KW - in vitro expression
KW - polycistronic mRNA
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62642
ER -
TY - JOUR
A1 - McCarthy, J. E.
A1 - Schairer, H. U.
A1 - Sebald, Walter
T1 - Translational initiation frequency of atp genes from Escherichia coli: identification of an intercistronic sequence that enhances translation
N2 - The c, b and ö subunit genes of the Escherichia coli atp operon were cloned individually in an expression vector between the tac fusion promoter and the galK gene. The relative rates of subunit synthesis directed by the cloned genes were similar in vitro andin vivo and compared favourably with the subunit stoichiometry of the assembled proton-translocating A TP synthase of E. coli in vivo. The rate of synthesis of subunit c was at least six times that of subunit b and 18 times that of subunit ö. Progressive shortening of the long intercistronic sequence lying upstream of the subunit c gene showed that maximal expression of this gene is dependent upon the presence of a sequence stretching > 20 bp upstream of the Shine-Dalgarno site. This sequence thus acts to enhance the rate of translational initiation. The possibility that similar sequences might perform the same function in other operons of E. coli and bacteriophage A is also discussed. Translation of the subunit b cistron is partially coupled to translation of the preceding subunit c cistron. In conclusion, the expression of all the atp operon genes could be adjusted to accommodate the subunit requirements of A TP synthase assembly primarily by means of mechanisms which control the efficiency of translational initiation and re-initiation at the respective cistron start codons.
KW - Biochemie
KW - E. coli atp operon
KW - subunit stoichiometry
KW - in vitro and in vivo expression
KW - translational initiation
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62657
ER -
TY - JOUR
A1 - Lindenmaier, W.
A1 - Dittmar, K. E.
A1 - Hauser, H.
A1 - Necker, A.
A1 - Sebald, Walter
T1 - Isolation of a functional human interleukin 2 gene from a cosmid library by recombination in vivo
N2 - A method has been developed that allows the isolation of genomic clones from a cosmid library by homologaus recombination in vivo. This method was used to isolate a human genomic interleukin 2 (IL2) gene. The genomic cosmid library was packaged in vivo into A. phage particles. A recombination-proficient host strain carrying IL2 cDNA sequences in a non-homologaus plasmid vector was infected by the packaged cosmid library. After in vivo packaging and reinfection, recombinants carrying the antibiotic resistance genes of both vectors were selected. From a recombinant cosmid clone the chromosomal IL2 genewas restored. After DNA mediated gene transfer into mouse Ltk- cells human IL2 was expressed constitutively.
KW - Biochemie
KW - Recombinant DNA
KW - DNA mediated gene transfer
KW - expression plasmid
KW - screening
KW - packaging
KW - bacteriophage lambda
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62662
ER -
TY - JOUR
A1 - Schartl, Manfred
A1 - Schmidt, C. R.
A1 - Anders, A.
A1 - Barnekow, A.
T1 - Elevated expression of the cellular src gene in tumors of differing etiologies in Xiphophorus
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61889
ER -
TY - JOUR
A1 - Hügle, Barbara
A1 - Scheer, Ulrich
A1 - Franke, Werner W.
T1 - Ribocharin: a nuclear M\(_r\) 40,000 protein specific to precursor particles of the large ribosomal subunit
N2 - Using a monoclonal antibody (No-194) we have identified, in Xenopus laevis and other amphibia, an acidic protein of M, 40,000 (ribocharin) which is specifically associated with the granular component of the nucleolus and nucleoplasmic 65S particles. These particles contain the nuclear 28S rRNA and apparently represent the precursor to the large ribosomal subunit in nucleocytoplasmic transit. By immunoelectron microscopy ribocharin has been localized in the granular component of the nucleolus and in interchromatin granules. During mitosis ribocharin-containing particles are associated with surfaces of chromosomes and are recollected in the reconstituting nucleoli in late telophase. We suggest that ribocharin is a specific component of precursor particles of the large ribosomal subunit, which dissociates from the 65S particle before passage through the nuclear envelope, and is reutilized in ribosome biogenesis.
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-41169
ER -
TY - JOUR
A1 - Hügle, Barbara
A1 - Hazan, Rachel
A1 - Scheer, Ulrich
A1 - Franke, Werner W.
T1 - Localization of ribosomal protein S1 in the granular component of the interphase nucleolus and its distribution during mitosis
N2 - Using antibodies to various nucleolar and ribosomal proteins, we define, by immunolocalization in situ, the distribution of nucleolar proteins in the different morphological nucleolar subcompartments. In the present study we describe the nucleolar localization of a specific ribosomal protein (51) by immunofluorescence and immunoelectron microscopy using a monoclonal antibody (R5 1-105). In immunoblotting experiments, this antibody reacts specifically with the largest and most acidic protein of the small ribosomal subunit (51) and shows wide interspecies cross-reactivity from amphibia to man. Beside its localization in cytoplasmic ribosomes, this protein is found to be specifically localized in the granular component of the nucleolus and in distinct granular aggregates scattered over the nucleoplasm. This indicates that ribosomal protein 51, in contrast to reports on other ribosomal proteins, is not bound to nascent pre-rRNA transcripts but attaches to preribosomes at later stages of rRNA processing and maturation. This protein is not detected in the residual nucleolar structures of cells inactive in rRNA synthesis such as amphibian and avian erythrocytes. During mitosis, the nucleolar material containing ribosomal protein 51 undergoes a remarkable transition and shows a distribution distinct from that of several other nucleolar proteins. In prophase, the nucleolus disintegrates and protein 51 appears in numerous small granules scattered throughout the prophase nucleus. During metaphase and anaphase, a considerable amount of this protein is found in association with the surfaces of all chromosomes and finely dispersed in the cell plasm. In telophase, protein 51-containing material reaccumulates in granular particles in the nucleoplasm of the newly formed nuclei and, finally, in the re-forming nucleoli. These observations indicate that the nucleolus-derived particles containing ribosomal protein 51 are different from cytoplasmic ribosomes and, in the living cell, are selectively recollected after mitosis into the newly formed nuclei and translocated into a specific nucleolar subcompartment, i.e ., the granular component. The nucleolar location of ribosomal protein 51 and its rearrangement du'ring mitosis is discussed in relation to the distribution of other nucleolar proteins.
KW - Cytologie
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39695
ER -
TY - JOUR
A1 - Dandekar, Thomas
A1 - Gramsch, Christian
A1 - Houghton, Richard A.
A1 - Schultz, Rüdiger
T1 - Affinity purification of \(\beta\)-endorphin-like material from NG108CC15 cells by means of the monoclonal \(\beta\)-endorphin antibody 3-E7
N2 - No abstract available
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29896
ER -
TY - JOUR
A1 - Linsenmair, Karl Eduard
T1 - Individual and family recognition in subsocial arthropods, in particular in the desert isopod Hemilepistus reaumuri
N2 - Individual recogmtlon in the non-eusocial arthropods is, according to our present knowledge, predominantly found in the frame of permanent or temporary monogamy. In some cases, e. g. in stomatopods and possibly other marine crustaceans too, individual recognition may serve to allow identification of (i) individuals within dominance hierarchies or (ii) neighbours in territorial species thus helping to avoid the repetition of unnecessary and costly fights. Kin recognition is experimentally proven only in some isopod species (genera Hemilepistus and Porcel/io) and in the primitive cockroach (termite?) Cryptocercus. The «signatures» or «discriminators» used in the arthropods are chemical. It is assumed that the identifying substances are mainly genetically determined and in this paper I shall discuss possible evolutionary origins. The main part of this account is devoted to the presentation of some aspects of the highly developed individual and kin identification and recognition system in the desert isopod Hemilepistus reaumuri - a pure monogamous species in which pairs together with their progeny form strictly exclusive family units. Amongst other things problems of (i) mate choice, (ii) learning to recognize a partner, (iii) avoiding the un adaptive familiarization with aliens are treated. Monogamy under present conditions is for both sexes the only suitable way of maximizing reproductive success; an extremely strong selection pressure must act against every attempt to abandon monogamy under the given ecological conditions. The family «badges» which are certainly always blends of different discriminator substances are extremely variable. This variability is mainly due to genetical differences and is not environmentally caused. It is to be expected that intra-family variabiliry exists in respect of the production of discriminator substances. Since the common badge of a family is the result of exchanging and mixing individual substances, and since the chemical nature of these discriminators requires direct body contacts in order to acquire those substances which an individual does not produce itself, problems must arise with molting. These difficulties do indeed exist and they are aggravated by the fact that individuals may produce substances which do not show up in the common family badge. An efficient learning capability on the one hand and the use of inhibiting properties of newly molted isopods help to solve these problems. In the final discussion three questions are posed and - partly at least - answered; (i) why are families so strictly exclusive, (ii) how many discriminator substances have to be produced to provide a variability allowing families to remain exclusive under extreme conditions of very high population densities, (iii) what is the structure of the family badge and what does an individual have to learn apart from the badge in order not to mistake a family member for an alien or vice versa.
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33957
ER -
TY - JOUR
A1 - Anders, F.
A1 - Schartl, Manfred
A1 - Barnekow, A.
A1 - Schmidt, C. R.
A1 - Luke, W.
A1 - Jaenel-Dess, G.
A1 - Anders, A.
T1 - The genes that carcinogens act upon
N2 - No abstract available.
KW - Onkogen
Y1 - 1985
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-72704
ER -
TY - JOUR
A1 - Barnekow, Angelika
A1 - Gessler, Manfred
T1 - Activation of the pp60\(^{c-src}\) kinase during differentiation of monomyelocytic cells in vitro
N2 - Tbe proto-oncogene c-src, the cellular homolog of the Rous sarcoma virus (RSV) transforming gene v-src, is expressed in a tissue-specific and age-dependent manner. Its physiological function, although still unknown, appears to be more closely related to differentiation processes than to proliferation processes. To obtain more information about the physiological role of the c-src gene in cells, we have studied differentiation-dependent alterations using the human HL-60 leukaemia cell line as a model system. Induction of monocytic and granulocytic differentiation of HL-60 cells by 12-0-tetradecanoylphorbol-13-acetate (TPA) and dimethylsulfoxide (DMSO) is associated with an activation of the pp60c-src tyrosine kinase, but not with increased c-src gene expression. Control experiments exclude an interaction of TPA and DMSO themselves with the pp60c-src kinase.
KW - Biochemie
KW - c-src
KW - differentiation
KW - protein tyrosine kinase
KW - protooncogene
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59278
ER -
TY - JOUR
A1 - Weich, H. A.
A1 - Sebald, Walter
A1 - Schairer, H. U.
A1 - Hoppe, J.
T1 - The human osteosarcoma cell line U-2 OS expresses a 3.8 kilobase mRNA which codes for the sequence of the PDGF-B chain
N2 - A cDNA clone of about 2500 basepairswas prepared from the human osteosarcoma cellline U-2 OS by hybridizing with a v-sis probe. Sequence analysis showed that this cDNA contains the coding region for the PDGF-B chain. Here we report that the mitogen secreted by these osteosarcoma cells contains the PDGF-B chain and is probably a homodimer of two B-chains.
KW - Biochemie
KW - Platelet-derived growthfactor
KW - cDNA
KW - Oncogene
KW - Tumor cell
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62588
ER -
TY - JOUR
A1 - Hoppe, J.
A1 - Gatti, D.
A1 - Weber, H.
A1 - Sebald, Walter
T1 - Labeling of individual amino acid residues in the membrane-embedded F\(_0\) part of the F\(_1\) F\(_0\) ATP synthase from Neurospora crassa. Influence of oligomycin and dicyclohexylcarbodiimide
N2 - Three F0 subunits and the F\(_1\) subunit P of the ATP synthase from Neurospora crassa were labeled with the lipophilic photoactivatable reagent 3-(trifluoromethyl)-3-(m-[\(^{125}\)I]iodophenyl)diazirine ([\(^{125}\)I]TID). In the proteolipid subunit which was the most heavily labeled polypeptide labeling was confmed to five residues at the NH2-terminus and five residues at the C-terminus ofthe protein. Labeling occurred at similar positions compared with the homologaus protein (subunit c) in the ATP synthase from Escherichia coli, indicating a similar structure of the proteolipid subunits in their respective organisms. The inhibitors oligomycin and dicyclohexylcarbodiimide did not change the pattern of accessible surface residues in the proteolipid, suggesting that neither inhibitor induces gross conformational changes. However, in the presence of oligomycin, the extent oflabeling in some residues was reduced. Apparently, these residues provide part of the binding site for the inhibitor. After reaction with dicyclohexylcarbodiimide an additional labeled amino acid was found at position 65 corresponding to the invariant carbodümide-binding glutamic acid. These results and previous observations indicate that the carboxyl side chain of Glu-65 is located at the protein-lipid interphase. The idea is discussed that proton translocation occurs at the interphase between different types if F\(_0\) subunits. Dicyclohexylcarbodiimide or oligomycin might disturb this essential interaction between the F\(_0\) subunits.
KW - Biochemie
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62598
ER -
TY - JOUR
A1 - Hoppe, J.
A1 - Sebald, Walter
T1 - Topological studies suggest that the pathway of the protons through F\(_0\) is provided by amino acid residues accessible from the lipid phase
N2 - The structure of the F0 part of ATP synthases from E. coli and Neurospora crassa was analyzed by hydrophobic surface labeling with [125I]TID. In the E. co/i F0 all three subunits were freely accessible to the reagent, suggesting that these subunits are independently integrated in the membrane. Labeted amino acid residues were identified by Edman degradation of the dicyclohexylcarbodiimide binding (DCCD) proteins from E. coli and Neurospora crassa. The very similar patterns obtained with the two homologaus proteins suggested the existence of tightly packed cx-helices. The oligomeric structure of the DCCD binding protein appeared to be very rigid since little, if any, change in the labeling patternwas observed upon addition of oligomycin or DCCD to membranes from Neurospora crassa. When membrancs were pretrcated with DCCD prior to the reaction with [125I]TID an additionally labeled amino acid appeared at the position of Glu·65 which binds DCCD covalently, indicating the Jocation of this inhibitor on the outside of the oligomer. It is suggested that proton conduction occurs at the surface of the oligomer of the DCCD binding protein. Possibly this oligomer rotates against the subunit a or b and thus enables proton translocation. Conserved residues in subunit a, probably located in the Iipid bilayer, might participate in the pro· ton translocation mechanism.
N2 - La structure de la partie F0 de l'ATP synthase a ete analysee au moyen de marquage par /e reactif hydrophobe TJD[125 I]. Les trois sous-unites de E. coli F0 sont accessibles au reactif ce qui semble indiquer que ces sous-unites sont integrees dans Ia membrane defaron independante. Les amino-acides marques ont ete identifies par Ia degradation d'Edman des profeines d'E. coli et de Neurospora associees au dicyclohexylcarbodiimide (DCCD). L 'analogie des courbes obtenues pour /es deux proteines homologues suggere l'existence d'a-helices rangees de faron serree. La structure oligomerique de Ia proreine associee au DCCD semble etre tres rigide puisque pratiquement aucun changement dans /e marquage n 'a ete observe par addition d'oligomycine ou de DCCD aux membranes de Neurospora crassa. Quand /es membranes sont traitees avec /e DCCD avant Ia reaction avec TJD[125 I], un amino-acide additionnellement marque apparait a Ia position Glu·65 et forme avec le DCCD une Iiaison covalente. Ce dernier resu/tat indique Ia localisation de cet inhibiteur a /'exterieur de J'oligo· mere. II semble donc que Ia conduction des protons ait lieu a Ia surface de /'oligomere de Ia proteine associee au DCCD. II serait possib/e que l'o/igomere se retourne contre Ia sous-unite a ou b, permettunt de ce fait Ia translocation des protons. Les residus conserves de Ia sous-unite a, probab/ement Jocalises dans Ia double couche lipidique, pourraient participer au mecanisme de translocation des protons.
KW - Biochemie
KW - conduction de protons
KW - proteines membranaires
KW - carbenes
KW - proton conduction
KW - membrane proteins
KW - carbenes
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62602
ER -
TY - JOUR
A1 - Gabellini, N.
A1 - Sebald, Walter
T1 - Nucleotide sequence and transcription of the fbc operon from Rhodopseudomonas sphaeroides. Evaluation of the deduced amino acid sequences of the FeS protein, cytochrome b and cytochrome c\(_1\)
N2 - No abstract available
KW - Biochemie
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62615
ER -
TY - JOUR
A1 - McCarthy, J. E.
A1 - Sebald, Walter
A1 - Gross, G.
A1 - Lammers, R.
T1 - Enhancement of translational efficiency by the Escherichia coli atpE translational initiation region: its fusion with two human genes
N2 - No abstract available
KW - Biochemie
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62626
ER -
TY - JOUR
A1 - Kobelt, Frank
A1 - Linsenmair, Karl Eduard
T1 - Adaptations of the reed frog Hyperolius viridiflavus to its arid environment. I. The skin of Hyperolius viridiflavus nitidulus in wet and dry season conditions.
N2 - Hyperolius viridiflavus nitidulus inhabits parts of the seasonally very hot and dry West African savanna. During the long lasting dry season, the small frog is sitting unhidden on mostly dry plants and has to deal with high solar radiation load (SRL), evaporative water loss (EWL) and small energy reserves. It seems to be very badly equipped to survive such harsh climatic conditions (unfavorable surface to volume ratio, very limited capacity to störe energy and water). Therefore, it must have developed extraordinary efficient mechanisms to solve the mentioned Problems. Some of these mechanisms are to be looked for within the skin of the animal (e.g. protection against fast desiccation, deleterious effects of UV radiation and over-heating). The morphology of the wet season skin is, in most aspects, that of a "normal" anuran skin. It differs in the Organization of the processes of the melanophores and in the arrangement of the chromatophores in the Stratum spongiosum, forming no "Dermal Chromatophore Unit". During the adaptation to dry season conditions the number of iridophores in dorsal and ventral skin is increased 4-6 times compared to wet season skin. This increase is accompanied by a very conspicuous change of the wet season color pattern. Now, at air temperatures below 35° C the color becomes brownish white or grey and changes to a brilliant white at air temperatures near and over 40° C. Thus, in dry season State the frog retains its ability for rapid color change. In wet season State the platelets of the iridophores are irregularly distributed. In dry season State many platelets become arranged almost parallel to the surface. These purine crystals probably act as quarter-wave-length interference reflectors, reducing SRL by reflecting a considerable amount of the radiated energy input. EWL is as low as that of much larger xeric reptilians. The impermeability of the skin seems to be the result of several mechanisms (ground substance, iridophores, lipids, mucus) supplementing each other. The light red skin at the pelvic region and inner sides of the limbs is specialized for rapid uptake of water allowing the frog to replenish the unavoidable EWL by using single drops of dew or rain, available for only very short periods.
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30551
ER -
TY - JOUR
A1 - Scheer, Ulrich
A1 - Hansmann, Paul
A1 - Falk, Heinz
A1 - Sitte, Peter
T1 - Ultrastructural localization of DNA in two Cryptomonas species by use of a monoclonal DNA-antibody
N2 - Immunogold cytochemistry - DNA localization - Cryptomonas nucleomorph The distribution and subcellular localization of DNA in the unicellular alga Cryptomonas has been investigated electron-microscopically by indirect immunocytochemistry, using a monoclonal DNA antibody and a gold-Iabeled secondary antibody. This technique proved to be very sensitive and entirely specific. DNA could be demonstrated in four different compartments (nucleus, nucleomorph, plastid, and mitochondrion). Within the plastid, DNA is concentrated in stroma regions that are localized preferentially around the center of the organelle. The mitochondrion contains several isolated DNA-containing regions (nucleoids). Within the nucleus, most of the DNA is localized in the 'condensed' chromatin. DNA was also detectable in small areas of the nucleolus, whereas the interchromatin space of the nucleus appeared almost devoid of DNA. Within the nucleomorph, DNA is distributed inhomogeneously in the matrix. DNA could furthermore be detected in restricted areas of the 'fibrillogranular body' of the nucleomorph, resembling the situation encountered in the nucleol us. The presence of DNA and its characteristic distribution in the nucleomorph provide additional, strong evidence in favour of the interpretation of that organelle as the residual nucleus of a eukaryotic endosymbiont in Cryptomonas.
KW - Cytologie
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39746
ER -
TY - JOUR
A1 - Schultz, Rüdiger
A1 - Metzner, Katharina
A1 - Dandekar, Thomas
A1 - Gramsch, Christian
T1 - Opiates induce long-term increases in prodynorphin derived peptide levels in the guinea-pig myenteric plexus
N2 - No abstract available
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29809
ER -
TY - JOUR
A1 - Hadjiolova, Krassimira
A1 - Rose, Kathleen M.
A1 - Scheer, Ulrich
T1 - Immunolocalization of nucleolar proteins after D-galactosamine-induced inhibition of transcription in rat hepatocytes
N2 - No abstract available
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33205
ER -
TY - JOUR
A1 - Reimer, Georg
A1 - Scheer, Ulrich
A1 - Peters, Jan-Michael
A1 - Tan, Eng M.
T1 - Immunolocalization and partial characterization of a nucleolar autoantigen (PM-Scl) associated with polymyositis / scleroderma overlap syndromes.
N2 - Precipitating anti-PM-Sel antibodies are present in sera from patients with polymyositis. scleroderma. and polymyositis/scleroderma overlap syndromes. By indirect immunofluorescence microscopy. anti-PM-Scl antibodies stained the nucleolus in cells of different tissues and species. suggesting that the antigen is highly conserved. By electron microscopy, anti-PM-Scl antibodies reacted primarily with the granular component of the nuc1eolus. Drugs that inhibit rRNA synthesis had a marked effect on the expression of PM-Scl antigen. In actinomycin D-treated cells, immunofluorescence staining by anti-PM-Scl was signüicantly reduced with residual staining restricted to the granular regions of nuc1eoli. Treatment with 5,6-dichloro-beta-D- ribofuranosylbenzimidazole (DRB) also selectively reduced nuc1eolar staining. On a molecular level, anti-PM-Sel antibodies precipitated 11 polypeptides with molecular weights (Mr) ranging from 110,000 to 20,000. The Mr 80,000 and 20.000 polypeptides were phosphorylated. Evidence suggests that the PM-Scl antigen complex may be related to a prerlbosomal particle.
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33191
ER -
TY - JOUR
A1 - Linsenmair, Karl Eduard
T1 - Adaptations of the reed frog Hyperbolius viridiflavus to its arid environment: II. Some aspects of the water economy of H. viridiflavus nitidulus under wet and dry ...
N2 - Adaptations to aridity ofthe reedfrog Hyperolius viridiflavus nitidulus, living in different parts of the seasonally very dry and hot West African savanna, are investigated ...
KW - Zoologie
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78395
ER -
TY - JOUR
A1 - Scheer, Ulrich
T1 - Injection of antibodies into the nucleus of amphibian oocytes: an experimental means of interfering with gene expression in the living cell
N2 - No abstract available
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-41182
ER -
TY - JOUR
A1 - Mahsberg, Dieter
T1 - Contact chemoreception of prey in hunting scorpions
N2 - Scorpions commonly are assumed to hunt on living prey. But under laboratory conditions they also respond very sensitively to dead insects lying on the substrate. In many cases the motionless prey is seized and consumed. It was investigated how this behavior can be elicited. The buthid scorpions Androctonus australis (L.) and Buthus occitanus (Am.) not only find motionless prey again which was stung but managed to escape before dying: They also respond to extracts of the cuticle of prey insects. After touching prey marks' either with the tips of the chelae fingers or the tarsi of the walking legs or the pectine organs specific responses (searching, seizing, feeding) are released at a high rate. Behavioral experiments demonstrate for the first time the chemosensitivity of the pectine organs for which only mechanosensitivity had been proofed formerly. Mechanical as well as contact chemical stimulation of these organs cause scorpions to orient towards the stimulus source which is grasped, retained and consumed or rejected depending on its quality. The probably responsible chemosensitive receptors are already described in the literature. The possible adaptive value and the biological significance of contact chemoreception in prey catching and in other aspects of the life of scorpions is discussed.
KW - Skorpion
Y1 - 1986
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45784
ER -
TY - JOUR
A1 - Maueler, W.
A1 - Eigenbrodt, E.
A1 - Schartl, Manfred
T1 - Intermediary metabolism of normal and tumorous tissue of Xiphophorus (Teleostei: Poeciliidae)
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61855
ER -
TY - JOUR
A1 - Barnekow, A.
A1 - Schartl, Manfred
T1 - Comparative studies on the src proto-oncogene and its gene product pp60\(^{c-src}\) in normal and neoplastic tissues of lower vertebrates
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61869
ER -
TY - JOUR
A1 - Kleene, R.
A1 - Pfanner, N.
A1 - Pfaller, R.
A1 - Link, T. A.
A1 - Sebald, Walter
A1 - Neupert, W.
A1 - Tropschug, M.
T1 - Mitochondrial porin of Neurospora crassa: cDNA cloning, in vitro expression and import into mitochondria
N2 - No abstract available
KW - Biochemie
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62566
ER -
TY - JOUR
A1 - Römisch, J.
A1 - Tropschug, M.
A1 - Sebald, Walter
A1 - Weiss, H.
T1 - The primary structure of cytochrome c\(_1\) from Neurospora crassa
N2 - No abstract available
KW - Biochemie
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62578
ER -
TY - JOUR
A1 - Barnekow, A.
A1 - Paul, E.
A1 - Schartl, Manfred
T1 - Expression of the c-src protooncogene in human skin tumors
N2 - No abstract available
KW - Physiologische Chemie
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61870
ER -
TY - JOUR
A1 - Benavente, Ricardo
A1 - Rose, Kathleen M.
A1 - Reimer, Georg
A1 - Hügle-Dörr, Barbara
A1 - Scheer, Ulrich
T1 - Inhibition of nucleolar reformation after microinjection of antibodies to RNA polymerase I into mitotic cells
N2 - The formation of daughter nuclei and the reformation of nucleolar structures was studied after microinjection of antibodies to RNA polymerase I into dividing cultured cells (PtK2). The fate of several nucleolar proteins representing the three main structural subcomponents of the nucleolus was examined by immunofluorescence and electron microscopy. The results show that the RNA polymerase I antibodies do not interfere with normal mitotic progression or the early steps of nucleologenesis, i.e. , the aggregation of nucleolar material into prenucleolar bodies. However,they inhibit the telophasic coalescence of the prenucleolar bodies into the chromosomal nucleolar organizer regions, thus preventing the formation of new nucleoli. These prenucleolar bodies show a fibrillar organization that also compositionally resembles the dense fibrillar component of interphase nucleoli . We conclude that during normal nucleologenesis the dense fibrillar component forms from preformed entities around nucleolar organizer regions, and that this association seems to be dependent on the presence of an active form of RNA polymerase I.
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-33247
ER -
TY - JOUR
A1 - Scheer, Ulrich
A1 - Raska, I.
T1 - Immunocytochemical localization of RNA polymerase I in the fibrillar centers of nucleoli
N2 - No abstract available
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39618
ER -
TY - JOUR
A1 - Scheer, Ulrich
T1 - Structure of lampbrush chromosome loops during different states of transcriptional activity as visualized in the presence of physiological salt concentrations
N2 - Lampbrush chromosomes of amphibian oocytes were isolated in the presence of near-physiological salt concentrations, to preserve their native state, and studied by electron microscopy of ultrathin s~dions. The transcriptional state of the lampbrush chromosomes was experimentally modulated by incubating the oocytes for various time periods in medium containing actinomycin D. The observations show that the structure of the lateral loops changes rapidly in response to alterations in transcriptional activity. During decreasing transcriptional activity and reduced packing density of transcripts, the chromatin axis first condensed into nucleosomes and then into an approximately 30 nm thick higher order chromatin fiber. Packaging of the loop axis into supranucleosomal structures may contribute to the foreshortening and retraction of the loops observed during inhibition of transcription and in later stages of meiotic prophase. The increasing packing density of the DNA during the retraction process of the loops could also be visualized by immunofluorescence microscopy using antibodies to DNA. The dependence of the loop chromatin structure on transcriptional activity is discussed in relation to current views of mechanisms involved in gene activation.
KW - lampbrush chromosomes
KW - chromatin structure
KW - electron microscopy
KW - immunofluorescence microscopy
KW - DNA antibodies
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-39304
ER -
TY - JOUR
A1 - Dandekar, Thomas
A1 - Schulz, R.
T1 - Evidence for the expression of peptides derived from three opioid precursors in NG 108CC15 hybrid cells
N2 - No abstract available
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-29909
ER -
TY - JOUR
A1 - Maschwitz, U.
A1 - Fiala, Brigitte
A1 - Dolling, W. R.
T1 - New trophobiotic symbioses of ants with South East Asian bugs
N2 - A trophobiotic relationship between two species of phloem-feeding plataspid bugs and an ant, Meranoplus mucronatus, was discovered on tree trunks in Malaysia. Similar relationships were found between coreid bugs and Crematogaster sp. and Anoplolepis longipes, on bamboo in the same area. The ants recruit to groups of the bugs and feed on the liquid, sugar-rich faeces of the larvae, stimulating release of the honeydew by tactile signals. They protect all stages of the bugs from disturbance by biting and by the use of defensive secretions. Phloem-feeding bugs in the families Plataspidae and Coreidae need long sty lets to pierce the thick bark of their host tree. The different methods of accommodating the resting stylets in these two families are described. The plataspids are described as Tropidotylus servus sp. novo and T. minister sp. novo A coreid previously reported in association with M. mucronatus in Malaya is described as Hygia cliens sp. novo The coreids on bamboo were determined as Cloresmus spp. and Notobitus affinis.
KW - Ants
KW - Coreidae
KW - Heteroptera
KW - Malaya
KW - New Species
KW - Plataspidae
KW - Trophobiosis
Y1 - 1987
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34030
ER -