@article{FrankeScheer1978,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {Morphology of transcriptional units at different states of activity},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41363},
  year      = {1978},
  abstract  = {The morphology of two forms of transcription ally active chromatin, the nucleoli and the loops of lampbrush chromosomes, has been examined after fixation in situ or after isolation and dispersion of the material in media of low ionic strengths, using a variety of electron microscopic preparation techniques (e.g. spread preparations with positive or negative staining or without any staining at all, with bright and dark field illumination, with autoradiography, after pretreatment of the chromatin with specific detergents such as Sarkosyl NL-30; transmission and scanning transmission electron microscopy of ultrathin sections). Nucleolar chromatin and chromosomes from oocytes of various amphibia and insects as well as from green algae of the family of the Dasycladaceae were studied in particular detail. The morphology of transcriptional units that are densely packed with lateral ribonucleoprotein fibrils, indicative of great transcriptional activity, was compared with that of chromatin of reduced lateral fibril density, including stages of drug-induced inhibition. The micrographs showed that under conditions which preserve the nucleosomal organization in condensed chromatin studied in parallel, nucleosomes are not recognized in transcriptionally active chromatin. This holds for the transcribed regions as well as for apparently untranscribed (i.e. fibril-free) regions interspersed between ('spacer') and/or adjacent to transcribed genes and for the fibril-free regions within transcriptional units of reduced fibril density. In addition, comparison oflengths of repeating units of isolated rDNA with those observed in spread nucleolar chromatin indicated that this DNA is not foreshortened and packed into nucleosomal structures. Granular particles which were observed, at irregular frequencies and in variable patterns, in some spacer regions, did not result in a proportional shortening of the spacer axis, and were found to be resistant to detergent treatment effective in removing most of the chromatin associated proteins including histones. Thus, these particles behave like RNA polymerases rather than nucleosomes. It is suggested that structural changes from nucleosomal packing to an extended form of DNA are involved in the transcriptional activation of chromatin.},
  language  = {en}
}
@article{FrankeScheer1970,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {The ultrastructure of the nuclear envelope of amphibian oocytes: a reinvestigation. II. The immature oocyte and dynamic aspects},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32102},
  year      = {1970},
  abstract  = {No abstract available},
  language  = {en}
}
@article{FrankeScheer1972,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {Structural details of dictyosomal pores},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32155},
  year      = {1972},
  abstract  = {Structural details of the dictyosomal pores in several plant cell types are described from tangential and cross sections of Golgi cisternae. Frequency distributions of the sizes of such Golgi pores are given and compared with the corresponding values of nuclear pores in the same cells. Golgi pore inner diameters are less homogeneously distributed and can be as small as 100 A or less. They are not simply cisterna I holes, but are often associated with centrally located electron dense granules or rods and with inner pore filaments. This organization, which is very common in dictyosomal pores in plant and animal cells, has some similarities with the structural architecture of nuclear envelope and annulate lamellar pore complexes. The particulate material associated with the dictyosomal pores shows spatial and structural relationship to cytoplasmic ribosomes. Possible modes of Golgi pore formation and some consequences of these observations for interpretation of nuclear pore structures are discussed.},
  language  = {en}
}
@article{FrankeScheer1970,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {The ultrastructure of the nuclear envelope of amphibian oocytes: a reinvestigation. I. The mature oocyte},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32098},
  year      = {1970},
  abstract  = {1 n order to review the contradictory statements on the ultrast ructure of the nuclear envelope, a study was undertaken combining section and negat ive stai ning electron microscopy on manually isolated oocyte nuclei and nuclear envelopes from six amphibian species including Anura as well as Urodela. The a ppeara nce of the negatively stained iso lated nuclear envelopes is described in deta il and the dependence on the preparation co nditions used is emphas ized . Pore complex structures such as pore perimeter, central granule, an nul ar components, interna l fibrils, and annu lus-attached fibrils could be identified by both techniques, negat ive staining and sect ions. Comparative studies show that no marked diffe rences ex ist in the structural data of the nuclear envelope among the investigated amphibians and the significance of the structural components is discussed. A model of the nuclea r pore complex based on the findings of the present investigation is prese nted.},
  language  = {en}
}
@article{FrankeScheer1971,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {Some structural differentiations in the HeLa cell: heavy bodies, annulate lamellae and cotte de maillet endoplasmic reticulum},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40614},
  year      = {1971},
  abstract  = {A small fraction of HeLa cells within an exponentially growing culture showed cisternal differentiations, such as cytoplasmic as well as intranuclear annulate lamellae and special smooth surfaced endoplasmic reticulum aggregates with a typical "Cotte de maillet" appearance. Additionally, clusters of dense granules were observed in the cytoplasm which were often associated with polysomes and strongly resembled the so-called "heavy bodies" known in particular in diverse oocytes. The functional meaning of these structures is discussed. Moreover, it is deduced from the ultrastructural identity of the pore complexes in the nuclear envelope and the cytoplasmic and intranuclear annulate lamellae that the pore complex material with its highly ordered arrangement is not a structure characteristic for nucleocytoplasmically migrating material, but rather is a general structural expression of a tight binding of ribonucleoprotein (RNP) to cisternal membranes. The pore complexes are thought of as representing sites of a RNP-storage. A similar functioning is hypothesized for the "heavy body"like aggregates. To the current hypotheses on the formation of annulate lamellae and the nuclear envelope, which are based on the concept of membrane continuities and constancies, the alternative view of a self assembly mechanism of membrane constituents on nucleoprotein structures is added.},
  subject      = {Cytologie},
  language  = {en}
}
@article{FrankeScheerFritsch1972,
  author    = {Franke, Werner W. and Scheer, Ulrich and Fritsch, Hansj{\"o}rg},
  title     = {Intranuclear and cytoplasmic annulate lamellae in plant cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32148},
  year      = {1972},
  abstract  = {No abstract available},
  language  = {en}
}
@article{FrankeScheerHerth1974,
  author    = {Franke, Werner W. and Scheer, Ulrich and Herth, Werner},
  title     = {Cytology, general and molecular cytology},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39499},
  year      = {1974},
  abstract  = {The present article had originally been conceived as a review on endomembranes, the plasma membrane, and the major product of membrane-bound activities, the cell wall material. However, limitations of space and the cascading number of pertinent literature articles made it necessary to confine this to one group of membranes and one type of cell wall components. Therefore, we shall begin our survey on the biochemical and cytological aspects of membranes by a review of the class of the pore complex bearing endomembranes, i.e. the nuclear envelope and the annulate lamellae (AL). Next year the membranes of the endoplasmic reticulum and the dictyosomes will be dealt with in conjunction with a discussion of the various intracellular vesicles, the tonoplast and the plasmalemma.},
  subject      = {Botanik},
  language  = {en}
}
@article{FrankeScheerHerth1973,
  author    = {Franke, Werner W. and Scheer, Ulrich and Herth, Werner},
  title     = {Cytologie, allgemeine und molekulare Cytologie},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40547},
  year      = {1973},
  abstract  = {No abstract available},
  language  = {de}
}
@article{FrankeScheerKrohneetal.1981,
  author    = {Franke, Werner W. and Scheer, Ulrich and Krohne, Georg and Jarasch, Ernst-Dieter},
  title     = {The nuclear envelope and the architecture of the nuclear periphery},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33108},
  year      = {1981},
  abstract  = {No abstract available},
  language  = {en}
}
@article{FrankeScheerSpringetal.1976,
  author    = {Franke, Werner W. and Scheer, Ulrich and Spring, Herbert and Trendelenburg, Michael F. and Krohne, G.},
  title     = {Morphology of transcriptional units of rDNA: evidence for transcription in apparent spacer intercepts and cleavages in the elongating nascent RNA},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39681},
  year      = {1976},
  abstract  = {Several types of "irregular" structures in the arrangement of lateral fibrils were noted in electron microscopic preparations of transcriptionally active nucleolar chromatin from various plant and animal cells. Such forms include: I. Disproportionately long lateral fibrils which occur either as individual fibrils or in groups; 2. "Prelude complexes" and other arrangements of lateral fibrils in apparent spacer intercepts; 3. Thickening of the rDNA chromatin axis at the starting end of pre-rRNA matrix units; 4. Extremely long matrix units , the length of which exceeds that of the rDNA (double-strand) sequence complementary to the specific pre-rRN A (for abbreviations see text). In addition, the stability of high molecular weight RNAs contained in the nucleolar ribonucleoproteins during the preparation for electron microscopy was demonstrated by gel electrophoresis. The observations indicate that the morphological starting point of a pre-rRNA matrix unit is not necessarily identical with the initiation site for synthesis of pre-rRNA, but they rather suggest that the start of the transcriptional unit is located at least O.2-D.8 JLm before the matrix unit and that parts of the "apparent spacer" are transcribed. It is proposed that the pre-rRN A molecules do not represent the primary product of rDNA transcription but rather relatively stable intermediate products that have already been processed during transcription.},
  language  = {en}
}
@article{FrankeScheerTrendelenburgetal.1976,
  author    = {Franke, Werner W. and Scheer, Ulrich and Trendelenburg, Michael F. and Spring, Herbert and Zentgraf, Hanswalter},
  title     = {Absence of nucleosomes in transcriptionally active chromatin},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40646},
  year      = {1976},
  abstract  = {The ultrastructure of twO kinds of transcription ally active chromatin, the lampbrush chromosome loops and the nucleoli from amphibian oocytes and primary nuclei of the green alga Acetabularia, has been examined after manual isolation and dispersion in low salt media of slightly alkaline pH using various electron microscopic staining techniques (positive staining, metal shadowing, negative staining, preparation on positively charged films, etc.) and compared with the appearance of chromatin from various somatic cells (hen erythrocytes, rat hepatocytes, ClIltured murine sarcoma cells) prepared in parallel. While typical nucleosomes were revealed with all the techniques for chromatin from the latter three cell system, no nucleosomes were identified in either the lampbrush chromosome structures or the nucleolar chromatin. Nucleosomal arrays were absent not only in maximally fibril-covered matrix units but also in fibril-free regions between transcriptional complexes, including the apparent spacer intercepts between different transcriptional units. Moreover, comparisons of the length of the repeating units of rDNA in the transcribed state with those determined in the isolated rDNA and with the lengths of the first stable product of rDNA transcription, the pre-rRNA, demonstrated that the transcribed rDNA was not significantly shortened and/or condensed but rather extended in the transcriptional units. Distinct granules of about nucleosomal size which were sometimes found in apparent spacer regions as well as within matrix units of reduced fibril density were shown not to represent nucleosomes since their number per spacer unit was not inversely correlated with the length of the specific unit and also on the basis of their resistance to treatment with the detergent Sarkosyl NL-30. It is possible to structurally distinguish between transcriptionally active chromatin in which the DNA is extended in a non-nucleosomal form of chromatin and condensed, inactive chromatin within the typical nucleosomal package. The characteristic extended structure of transcriptionally active chromatin is found not only in the transcribed genes but also in non-transcribed regions within or between ("spacer") transcriptional units as well as in transcriptional units that are untranscribed amidst transcribed ones and/or have been inactivated for relatively short time. It is hypothesized that activation of transcription involves a transition from a nucleosomal to an extended chromatin organisation and that this structural transition is not specific for single "activated" genes but may involve larger chromatin regions, including adjacent untranscribed intercepts.},
  subject      = {Cytologie},
  language  = {en}
}
@article{FrankeScheerZentgraf1984,
  author    = {Franke, Werner W. and Scheer, Ulrich and Zentgraf, Hanswalter},
  title     = {Organization of transcriptionally active and inactive chromatin},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40588},
  year      = {1984},
  abstract  = {No abstract available},
  subject      = {Deutschland},
  language  = {en}
}
@article{FrankeSpringScheeretal.1975,
  author    = {Franke, Werner W. and Spring, Herbert and Scheer, Ulrich and Zerban, Heide},
  title     = {Growth of the nuclear envelope in the vegetative phase of the green alga Acetabularia. Evidence for assembly from membrane components synthesized in the cytoplasm.},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32403},
  year      = {1975},
  abstract  = {No abstract available},
  language  = {en}
}
@article{FrankeTrendelenburgScheer1973,
  author    = {Franke, Werner W. and Trendelenburg, Michael F. and Scheer, Ulrich},
  title     = {Natural segregation of nucleolar components in the course of plant cell differentiation},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32182},
  year      = {1973},
  abstract  = {Segregation of the nucleolar components is described in the differentiated nucleus of the generative cell in the growing Clivia and Lilium pollen tubes. This finding of a natural nucleolar segregation is discussed against the background of current views of the correlations of nucleolar morphology and transcriptional activity.},
  language  = {en}
}
@article{FrankeZentgrafScheer1973,
  author    = {Franke, Werner W. and Zentgraf, Hanswalter and Scheer, Ulrich},
  title     = {Membrane linkages at the nuclear envelope},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40596},
  year      = {1973},
  abstract  = {Electron-opaque material is shown in the perinuclear cisternae of various cell types to connect the inner and outer nuclear membrane faces. Similar bridges were observed between the outer nuclear membrane and the outer mitochondrial membrane. The intracisternal bridges of the nuclear envelope appear to be important for the structural stability of the perinuclear cisterna. Stable structural linkage of mitochondria to the outer nuclear membrane might be relevant to the understanding of the characteristic juxtanuclear accumulation of mitochondria and also provide arguments for the discussions of certain biochemical activities found in nuclear and nuclear membrane fractions.},
  subject      = {Cytologie},
  language  = {en}
}
@article{HadjiolovaRoseScheer1986,
  author    = {Hadjiolova, Krassimira and Rose, Kathleen M. and Scheer, Ulrich},
  title     = {Immunolocalization of nucleolar proteins after D-galactosamine-induced inhibition of transcription in rat hepatocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33205},
  year      = {1986},
  abstract  = {No abstract available},
  language  = {en}
}
@article{HockMoormannFischeretal.1993,
  author    = {Hock, Robert and Moormann, Antoon and Fischer, Dagmar and Scheer, Ulrich},
  title     = {Absence of somatic histone H1 in oocytes and preblastula embryos of Xenopus laevis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41350},
  year      = {1993},
  abstract  = {Available data on the occurrence and expression of somatic histone HI during oogenesis and early embryogenesis of Xenopus laevis are contradictory. In particular the reported presence of a large storage pool of histone HIA in oocytes is difficult to reconcile with the high transcriptional activity of all gene classes in this specific cell type. In the present study we have used polyclonal antibodies raised against somatic Xenopus histone HI (HIA and HIA/B) for combined immunoblotting experiments to quantitate HI pools and immunolocalization studies to visualize chromosome- bound HI. Both approaches failed to detect soluble or chromosomal histone HI in vitellogenic oocytes, eggs, and cleavage-stage embryos up to early blastula. In addition, chromatin assembled in Xenopus egg extract was also negative for histone HI as revealed by immunofluorescence microscopy. Lampbrush chromosomes not only lacked histone HI but also the previously identified histone HI-like B4 protein (Smith et al., 1988, Genes Dev. 2,1284-1295). In contrast, chromosomes of eggs and early embryos fluoresced brightly with anti-B4 antibodies. Our results lend further support to the view that histone HI expression is developmentally regulated during Xenopus oogenesis and embryogenesis similar to what is known from other species.},
  language  = {en}
}
@article{HuegleHazanScheeretal.1985,
  author    = {H{\"u}gle, Barbara and Hazan, Rachel and Scheer, Ulrich and Franke, Werner W.},
  title     = {Localization of ribosomal protein S1 in the granular component of the interphase nucleolus and its distribution during mitosis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39695},
  year      = {1985},
  abstract  = {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.},
  subject      = {Cytologie},
  language  = {en}
}
@article{HuegleScheerFranke1985,
  author    = {H{\"u}gle, Barbara and Scheer, Ulrich and Franke, Werner W.},
  title     = {Ribocharin: a nuclear M\(_r\) 40,000 protein specific to precursor particles of the large ribosomal subunit},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41169},
  year      = {1985},
  abstract  = {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.},
  language  = {en}
}
@article{KleinschmidtScheerDabauvalleetal.1983,
  author    = {Kleinschmidt, J{\"u}rgen A. and Scheer, Ulrich and Dabauvalle, Marie-Christine and Bustin, Michael and Franke, Werner W.},
  title     = {High mobility group proteins of amphibian oocytes: a large storage pool of a soluble high mobility group-1-like protein and involvement in transcriptional events},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33250},
  year      = {1983},
  abstract  = {No abstract available},
  language  = {en}
}
@article{KnechtScheer1972,
  author    = {Knecht, Sigrid and Scheer, Ulrich},
  title     = {Die Liste der Vogelarten von S. Miguel (Azoren) des Gaspar Fructuoso (gestorben 1591)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41402},
  year      = {1972},
  abstract  = {No abstract available},
  language  = {de}
}
@article{KnechtScheer1968,
  author    = {Knecht, Sigrid and Scheer, Ulrich},
  title     = {Laut{\"a}ußerung und Verhalten des Azoren-Buchfinken (Fringilla coelebs moreletti Pucheran)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39479},
  year      = {1968},
  abstract  = {Einleitung und Methode S. 155. - Brutbiologie S. 155. - Motivgesang S. 157. - Sozialruf (Social Call) S. 161. - Entwicklung des Sozialrufs S. 164. - Brumimmungsruf (Regenruf) S. 165. - Flugruf S. 166. - Alarmruf eines Jungvogels S. 167. - Bestimmung der ReviergroBe S. 167. - Zusammenfassung S. 168. - Summary S. 168. - Literaturverzeichnis S. 169. Es wird untersucht, ob die Azoren-Buchfinken "Rassengesang" und "Rassenrufe" haben. Gesange und Rufe wurden auf Tonband aufgenommen und klangspek trogra phiert. Motivgesang. Jedes cJ beherrscht 2-6 verschiedene Gesangsformen, wobei stets eine "Alltagsform" mit der stark vereinfachten Phrase di-djah endigt. Die anderen, weniger haufigeren Gesangsformen ("Sonntagsformen") zeigen eine besser ausgearbeitete Endphrase, die jedoch nie so kompliziert wie bei kontinentalen Buchfinken ist. In Gebieten, in denen sich bevorzugt Kanarienvogel aufhalten, konnen Buchfinken Gesangselemente iibernehmen. Sozialruf. Das kontinentale pink ist auf alIen Azoreninseln durch ga ersetzt, so daB man von einem Rassenruf sprechen kann. Er ist mit starker Aggressionsneigung verkniipft. Der Sozialruf zeigt einen weiten Frequenzumfang, hervorgerufen durch mehrere simultane Noten. Brutstimmungsruf (Regenruf). Eine Anzahl verschiedener Rufe wurde spektrographiert. Vom cJ ist er bei maBiger Gefahr, aber auch spontan (30-70 Rufe/Min.) zu horen. Flugruf. Er scheint mit dem Flugruf der Nominatform identisch zu sein. Bestimmung der Reviergrope. Ein cJ wurde innerhalb seines Reviers an die "akustische Leine" genommen und bis zu den Reviergrenzen gezogen. Verhalten und LautauBerung anderten sich in Abhangigkeit von der jeweiligen Entfernung bis zur Reviergrenze.},
  subject      = {Tierpsychologie},
  language  = {de}
}
@article{KrohneFrankeScheer1978,
  author    = {Krohne, Georg and Franke, Werner W. and Scheer, Ulrich},
  title     = {The major polypeptides of the nuclear pore complex},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33078},
  year      = {1978},
  abstract  = {Nuclear envelopes of maturing oocytes of various amphibia contain an unusually high number of pore complexes in very close packing. Consequently, nuclear envelopes , which can be manually isolated in great purity, provide a remarkable enrichment of nuclear pore complex material, relative to membranous and other interporous structures. When the polypeptides of nuclear envelopes isolated from oocytes of Xenopl/s la evis and Triturus alpestris are examined by gel electrophoresis, visualized either by staining with Coomassie blue or by radiotluorography after in vitro reaction with [3H]dansyl chloride , a characteristic pattern is obtained (10 major and 15 minor bands). This polypeptide pattern is radically different from that of the nuclear contents isolated from the same cell. Extraction of the nuclear envelope with high salt concentrations and moderateIy ac tive detergents such as Triton X- 100 results in the removal of membrane material but leaves most of the non-membranous structure of the pore complexes. The dry weight of the pore complex (about 0.2 femtograms) remains essentially unchanged during such extractions as measured by quantitative electron microscopy . The extracted preparations which are highly enriched in nuclear pore complex material contain only two major polypeptide components with apparent molecular weights of 150000 and 73000. Components of such an electrophoretic mobility are not present as major bands , if at all , in nuclear contents extracted in the same way. lt is concluded that these two polypeptides are the major constituent protein(s) of the oocyte nuclear pore complex and are specific for this structure. When nuclear envelopes are isolated from rat liver and extracted with high salt buffers and Triton X- 100 similar bands are predominant, but two additional major components of molecular weights of 78000 and 66000 are also recognized. When the rat liver nuclear membranes are further subfractionated material enriched in the 66000 molecular weight component can be separated from the membrane material, indicating that this is relatively loosely associated material , probably a part of the nuclear matrix . The results suggest that the nuclear pore complex is not only a characteristic ubiquitous structure but also contains similar, if not identical , skeletal proteins that are remarkably re sistant to drastic changes of ionic strength as weil as to treatments with detergents and thiol reagents.},
  language  = {en}
}
@article{MorenoDiazdelaEspinaFrankeKrohneetal.1982,
  author    = {Moreno-Diaz de la Espina, Susana and Franke, Werner W. and Krohne, Georg and Trendelenburg, Michael F. and Grund, Christine and Scheer, Ulrich},
  title     = {Medusoid fibril bodies: a novel type of nuclear filament of diameter 8 to 12 nm with periodic ultrastructure demonstrated in oocytes of Xenopus laevis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34116},
  year      = {1982},
  abstract  = {No abstract available},
  language  = {en}
}
@article{MuellerScheer1970,
  author    = {M{\"u}ller, R. and Scheer, Ulrich},
  title     = {Klangspektrographische Untersuchungen der Laut{\"a}ußerung beim Krallenfrosch, Xenopus laevis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40529},
  year      = {1970},
  abstract  = {No abstract available},
  language  = {de}
}
@article{ReimerRaskaScheeretal.1988,
  author    = {Reimer, Georg and Raska, Ivan and Scheer, Ulrich and Tan, Eng M.},
  title     = {Immunolocalization of 7-2-ribonucleoprotein in the granular component of the nucleolus},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33890},
  year      = {1988},
  abstract  = {Certain autoimmune sera contain antibodies against a nucleolar ribonucleoprotein particle associated with 7-2-RNA (R. Reddy et al. (1983) J. Bioi. Chem . 258, 1383; C. Hashimoto and J. A. Steitz (1983) J. Bioi. Chem. 258, 1379). In this study, we showed by immunofluorescence microscopy that antibodies reactive with 7-2-ribonucleoprotein immunolocalized in the granular regions of actinomycin D and 5,6-dichloro-I-j3-D-ribofuranosylbenzimidazole (DRB)-segregated nucleoli from Vero cells. By electron microscopic immunocytochemistry, antigen-antibody complexes were located in the granular component of transcriptionally active nucleoli from rat liver hepatocytes and HeLa cells. Anti-7- 2-RNP antibodies from two autoimmune sera immunoprecipitated a major protein of Mr 40,000 from e5S] methionine-Iabeled HeLa cell extract. The immunolocalization data suggest that 7-2-ribonucleoprotein may be involved in stages of ribosome biogenesis which take place in the granular component of the nucleolus, i.e., assembly, maturation, and/or transport of preribosomes},
  language  = {en}
}
@article{ReimerRoseScheeretal.1987,
  author    = {Reimer, Georg and Rose, Kathleen M. and Scheer, Ulrich and Tan, Eng M.},
  title     = {Autoantibody to RNA polymerase I in scleroderma sera},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34294},
  year      = {1987},
  abstract  = {Autoantibodies to components of the nucleolus are a unique serological feature of patients with scleroderma. There are autoantibodies of several specificities; one type produces a speckled pattern of nucleolar staining in immunofluorescence. In actinomycin D and 5,6-dichloro-{j-D-ribofuranosylbenzimidazoletreated Vero cells, staining was restricted to the fibrillar and not the granular regions. By double immunofluorescence, specific rabbit anti-RNA polymerase I antibodies stained the same fibrillar structures in drug-segregated nucleoli as scleroderma sera. Scleroderma sera immunoprecipitated 13 polypeptides from (35S)methionine-labeled HeLa cell extract with molecular weights ranging from 210,000 to 14,000. Similar polypeptides were precipitated by rabbit anti-RNA polymerase I antibodies, and their common identities were confirmed in immunoabsorption experiments. Microinjection of purified IgG from a patient with speckled nucleolar staining effectively inhibited ribosomal RNA transcription. Autoantibodies to RNA polymerase I were restricted to certain patients with scleroderma and were not found in other autoimmune diseases.},
  language  = {en}
}
@article{ReimerScheerPetersetal.1986,
  author    = {Reimer, Georg and Scheer, Ulrich and Peters, Jan-Michael and Tan, Eng M.},
  title     = {Immunolocalization and partial characterization of a nucleolar autoantigen (PM-Scl) associated with polymyositis / scleroderma overlap syndromes.},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33191},
  year      = {1986},
  abstract  = {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 sign{\"u}icantly 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.},
  language  = {en}
}
@article{ReinhardHalbrueggeScheeretal.1992,
  author    = {Reinhard, Matthias and Halbr{\"u}gge, Maria and Scheer, Ulrich and Wiegand, Christiane and Jockusch, Brigitte M. and Walter, Ulrich},
  title     = {The 46/50 kDa phosphoprotein VASP purified from human platelets is a novel protein associated with actin filaments and focal contacts},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34246},
  year      = {1992},
  abstract  = {Vasoactive agents which elevate either cGMP or cAMP inhibit platelet activation by pathways sharing at least one component, the 46/50 kDa vasodilator-stimulated phosphoprotein (V ASP). V ASP is stoichiometrically phosphorylated by both cGMP-dependent and cAMPdependent protein kinases in intact human platelets, and its phosphorylation correlates very well with platelet inhibition caused by cGMP- and cAMP-elevating agents. Here we report that in human platelets spread on glass, V ASP is associated predominantly with the distal parts of radial micro filament bundles and with microfilaments outlining the periphery, whereas less V ASP is associated with a central microfilamentous ring. V ASP is also detectable in a variety of different cell types including fibroblasts and epithelial cells. In fibroblasts, V ASP is concentrated at focal contact areas, along microfilament bundles (stress fibres) in a punctate pattern, in the periphery of protruding lamellae, and is phosphorylated by cGMP- and cAMP-dependent protein kinases in response to appropriate stimuli. Evidence for the direct binding of V ASP to F -actin is also presented. The data demonstrate that V ASP is a novel phosphoprotein associated with actin filaments and focal contact areas, i.e. transmembrane junctions between microfilaments and the extracellular matrix.},
  language  = {de}
}
@article{RoseSzopaHanetal.1988,
  author    = {Rose, Kathleen M. and Szopa, Jan and Han, Fu-Sheng and Cheng, Yung-Chi and Richter, Arndt and Scheer, Ulrich},
  title     = {Association of DNA topoisomerase I and RNA polymerase I: A possible role for topoisomerase I in ribosomal gene transcription},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33901},
  year      = {1988},
  abstract  = {RNA polymerase I preparations purified from a rat hepatoma contained DNA topoisomerase activity. The DNA topoisomerase associated with the polymerase had an Mr of 110000, required Mg2+ but not ATP, and was recognized by anti-topoisomerase I antibodies. When added to RNA polymerase I preparations containing topoisomerase activity, anti-topoisomerase I antibodies were able to inhibit the DNA relaxing activity of the preparation as well as RNA synthesis in vitro. RNA polymerase II prepared by analogous procedures did not contain topoisomerase activity and was not recognized by the antibodies. The topoisomerase I: polymerase I complex was reversibly dissociated by column chromatography on Sephacryl S200 in the presence of 0.25 M (NH4hS04. Topoisomerase I was immunolocalized in the transcriptionally active ribosomal gene complex containing RNA polymerase I in situ. These data indicate that topoisomerase I and RNA polymerase I are tightly complexed both in vivo and in vitro, and suggest a role for DNA topoisomerase I in the transcription of ribosomal genes.},
  language  = {en}
}
@article{RunggerCrippaTrendelenburgetal.1978,
  author    = {Rungger, M. and Crippa, M. and Trendelenburg, M. F. and Scheer, Ulrich and Franke, Werner W.},
  title     = {Visualization of rDNA spacer transcription in Xenopus oocytes treated with fluorouridine},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33082},
  year      = {1978},
  abstract  = {Under the intluence of 5-tluoro-uridine, the ultrastructure of the rDNA transcription units in Xenopus oocytes is altered. Whereas part of the matrix units maintains anormal aspect or shows various degrees of inhibition, in a strong proportion of the transcription units the alternating pattern of matrix units and fibril-free spacer regions is no longer recognized. Transcriptional complexes are found along the entire DNP axis, including the regions of the spacers. These observations support biochemical data on transcription in rDNA spacer region.},
  language  = {en}
}
@article{Scheer1982,
  author    = {Scheer, Ulrich},
  title     = {A novel type of chromatin organization in lampbrush chromosomes of Pleurodeles waltlii: visualization of clusters of tandemly repeated, very short transcriptional units},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41087},
  year      = {1982},
  abstract  = {A novel chromatin configuration is described in lampbrush chromosomes of Pleurodeles waltlii oocytes which is different from transcriptionally inactive chromatin as weil as from the various forms of transcribed chromatin hitherto described. This novel type of chromatin is not arranged in Christmas tree-Iike configurations of densely packed lateral ribonucleoprotein (RNP) fibriIs but is characterized by a periodic alternating pattern of thick and thin regions which occur in clusters 01 some 10,000 repeats. Each thickened unit with an average length of 45 nm contains two c10sely spaced particles, the putative RNA polymerases, and each thickened unit is separated from the next one by a beaded chromatin spacer with a length of about 80 nm. This chromatin spacer contains on average two particles of approximately 14 nm in diameter, assumed to be nucleosomes. The thickened regions are interpreted to represent short transcriptional units containing approximately 130 base pairs of DNA which are separated from each other by nontranscribed spacers of 240-400 base pairs of DNA. The possibility is discussed that these transcriptional units represent 5S rRNA or tRNA genes.},
  language  = {en}
}
@article{Scheer1970,
  author    = {Scheer, Ulrich},
  title     = {The ultrastructure of the nuclear envelope of amphibian oocytes: a reinvestigation. III. Actinomycin D-induced decrease in central granules within the pores.},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32110},
  year      = {1970},
  abstract  = {No abstract available},
  language  = {en}
}
@article{Scheer1975,
  author    = {Scheer, Ulrich},
  title     = {The rifamycin derivative AF/013 is cytolytic},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32429},
  year      = {1975},
  abstract  = {No abstract available},
  language  = {en}
}
@article{Scheer1978,
  author    = {Scheer, Ulrich},
  title     = {Changes of nucleosome frequency in nucleolar and non-nucleolar chromatin as a function of transcription: an electron microscopic study},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39750},
  year      = {1978},
  abstract  = {The morphology of nucleolar and non-nucleolar (Iampbrush chromosome loops) chromatin was studied in the electron microscope during states of reduced transcriptional activity in amphibian oocytes (Xenopus laevis, Triturus alpestris, T. cristatus). Reduced transcriptional activity was observed in maturing stages of oocyte development and after treatment with an inhibitor, actinomycin D. Strands of nucleolar chromatin appear smooth and thin, and contain only few, if any, nucleosomal particles in the transcribed units. This is true whether they are densely or only sparsely covered with lateral ribonucleoprotein fibrils. This smooth and non-nucleosomal character is also predominant in the interspersed, apparently nontranscribed rDNA spacer regions. During inactivation, however, nucleolar chromatin frequently and progressively assumes a beaded appearance in extended fibril-free-that is, apparently nontranscribed - regions. I n either fUll-grown 00- cytes or late after drug treatment, most of the nucleolar chromatin is no longer smooth and thin, but rather shows a beaded configuration indistinguishable from inactive non - nucleolar chromatin. In many chromatin strands, transitions of fibril-associated regions of smooth character into beaded regions wihout lateral fibrils are seen. Similarly, in the non-nucleolar chromatin of the retracting lampbrush chromosome loops, reduced transcriptional activity is correlated with a change from smooth to beaded morphology. Here, however, beaded regions are also commonly found interspersed between the more or less distant bases of the lateral fibrils, the putative transcriptional complexes. I n both sorts of chromatin, detergents (in particular Sarkosyl) that remove most of the chromatin proteins including histones from the DNA axis but leave the RNA polymerases of the transcriptional complexes attached were used to discriminate between polymerases and nucleosomal particles. The results suggest that nucleosomes are absent in heavily transcribed chromatin regions but are reformed after inactivation. In contrast to the findings with inactivated nucleolar genes, in lampbrush chromosome loops the beaded nucleosomal configuration appears to be assumed also in regions within transcriptional units that, perhaps temporarily, are not involved in transcription.},
  language  = {en}
}
@article{Scheer1973,
  author    = {Scheer, Ulrich},
  title     = {Nuclear pore flow rate of ribosomal RNA and chain growth rate of its precursor during oogenesis of Xenopus laevis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32178},
  year      = {1973},
  abstract  = {The number of ribosomal RNA molecules which are transferred through an average nuclear pore complex per minute into the cytoplasm (nuclear pore flow rate, NPFR) during oocyte growth of Xenopus laevis is estimated. The NPFR calculations are based on determinations of the increase of cytoplasmic rRNA content during defined time intervals and of the total number of pore complexes in the respective oogenesis stages. In the mid-la mpbrush stage (500:"700 I'm oocyte diameter) the NPFR is maximal with 2.62 rRNA molecules/ pore/ minute. Then it decreases to zero at the end of oogenesis. The nucleocytoplasmic RNA f10w rates determined are compared with corresponding values of other cell types. The molecular weight of the rRNA precursor transcribed in the extrachromosomal nucleoli of Xenopus lampbrush stage oocytes is determined by acrylamide gel electrophoresis to be 2.5 x 10· daltons. From the temporal increase of cytoplasmic rRNA (3.8 I'g per oocyte in 38 days) and the known number of simultaneously growing precursor molecules in the nucleus the chain growth rate of the 40 S precursor RNA is estimated to be 34 nucleotides per second.},
  language  = {en}
}
@article{Scheer1982,
  author    = {Scheer, Ulrich},
  title     = {Biologische Objekte im Transmissions-Elektronenmikroskop (Teil 4): Spreitungstechniken},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39652},
  year      = {1982},
  abstract  = {Visualizing nucleic acids (DNA, RNA), nucleoprotein complexes and chromatin requires the use of special electron microscopicspreading techniques. In part 4 (27 refs.), methods are outlined for spreading DNA and RNA molecules for electron microscopic observation, these methods using modifications of the basic protein film method developed by A. Kleinschmidt and R. K. Zahn (1959). Hybridization techniques that allow the observation of heteroduplexes formed between two DNA molecules or between DNA and RNA molecules are reviewed, with special emphasis being placed on the DNA-RNA hybrids as a tool for elucidating RNA splicing. Techniques for studying DNA-protein interactions without the use of a protein monolayer film are mentioned. Finally, the "Miller spreading technique" for visualizing the nucleosomal organization of eukaryotic chromatin as well as the transcription of genes is discribed and illustrated.},
  language  = {de}
}
@article{Scheer1987,
  author    = {Scheer, Ulrich},
  title     = {Structure of lampbrush chromosome loops during different states of transcriptional activity as visualized in the presence of physiological salt concentrations},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39304},
  year      = {1987},
  abstract  = {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.},
  language  = {en}
}
@article{Scheer1972,
  author    = {Scheer, Ulrich},
  title     = {The ultrastructure of the nuclear envelope of amphibian ooctyes: IV. On the chemical nature of the nuclear pore complex material},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39500},
  year      = {1972},
  abstract  = {In order to investigate the chemical composition of the nuclear pore complexes isolated nuclei from mature Xenopus laevis oocytes were manually fractioned into nucleo· plasmic aggregates and the nuclear envelopes. The whole isolation procedure takes no more than 60- 90 sec, and the pore complexes of the isolated envelopes are well preserved as demonstrated by electron microscopy. Minor nucleoplasmic and cytoplasmic contaminations associated with the isolated nuclear envelopes were determined with electron microscopic morphometry and were found to be quantitatively negligible as far as their mass and nucleic acid content is concerned. The RNA content of the fractions was determined by direct phosphorus analysis after differential alkaline hydrolysis. Approximately 9\% of the total nuclear RNA of the mature Xenopus egg was found to be attached to the nuclear envelope. The nonmembranous elements of one pore complex contain 0.41 X 10- 16 g RNA. This value agrees well with the content estimated from morphometric data. The RNA package density in the pore complexes (270 X 10- 15 g/fJ-3) is compared with the nucleolar, nucleoplasmic and cytoplasmic RNA concentration and is discussed in context with the importance of the pore complexes for the nucleo-cytoplasmic transport of RNA-containing macromolecules. Additionally, the results of the chemical analyses as well as of the 3H-actinomycin D autoradiography and of the nucleoprotein staining method of Bernhard (1969) speak against the occurence of considerable amounts of DNA in the nuclear pore complex structures.},
  language  = {en}
}
@article{Scheer1981,
  author    = {Scheer, Ulrich},
  title     = {Identification of a novel class of tandemly repeated genes transcribed on lampbrush chromosomes of Pleurodeles waltlii},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33153},
  year      = {1981},
  abstract  = {Electron microscope preparations of lampbrush chromosomes from oocytes of Pleurodeles waltl;; have revealed a new class of tandemly repeated genes. These genes are highly active, as judged by the close spacing of nascent transcripts. They occur in clusters of >100 copies and are transcribed in units containing roughly 940 base pairs of DNA that are separated by nontranscribed spacers of an estimated DNA content of 2,410 base pairs. The size and the pattern of arrangement of these transcription units can not be correlated with any of the repetitious genes so far described.},
  language  = {en}
}
@article{Scheer1986,
  author    = {Scheer, Ulrich},
  title     = {Das Chromatin : seine Struktur und Funktion},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-80790},
  year      = {1986},
  abstract  = {no abstract available},
  subject      = {Chromatin},
  language  = {de}
}
@article{Scheer1994,
  author    = {Scheer, Ulrich},
  title     = {Harold Garnet Callan 1917-1993},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-80789},
  year      = {1994},
  abstract  = {Professor Harold Gamet Callan, honorary member of the German Society for Cell Biology, died on the 3rd November 1993, at the age of 76. His name is inseparably connected with lampbrush chromosomes, the most spectacular and aesthetically ailuring form of chromosomes, which occupied the major part of his scientific career. " Mick" Callan's pioneering studies led to fruitful new concepts, served as a building block for many subsequent studies by others, and contributed enormously to our current understanding of chromosome organization and activity ...},
  subject      = {Harold Garnet Callan},
  language  = {en}
}
@article{Scheer1980,
  author    = {Scheer, Ulrich},
  title     = {Structural organization of spacer chromatin between transcribed ribosomal RNA genes in amphibian oocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41057},
  year      = {1980},
  abstract  = {Transcribed nucleolar chomatin, including the spacer regions interspersed between the rRNA genes, is different from the bulk of nontranscribed chromatin in that the DNA of these regions appears to be in an extended (B) conformation when examined by electron microscopy. The possibility that this may reflect artificial unfolding of nucleosomes during incubation in very low salt buffers as routinely used in such spread preparations has been examined by studying the influence of various ion concentrations on nucleolar chromatin structure. Amplified nucleolar chromatin of amphibian oocytes (Xenopus laevis, Pleurodeles waltlii, Triturus cristatus) was spread in various concentrations of NaCl (range 0 to 20 mM). Below 1 mM salt spacer chromatin frequently revealed a variable number of irregularly shaped beads, whereas above this concentration the chromatin axis appeared uniformly smooth. At all salt concentrations studied, however, the length distribution of spacer and gene regions was identical. Preparations fixed with glutaraldehyde instead of formaldehyde, or unftxed preparations, were indistinguishable in this respect. The observations indicate that (i) rDNA spacer regions are not compacted into nucleosomal particles and into supranucleosomal structures when visualized at chromatin stabilizing salt concentrations (e.g., 20 mM NaCl), and (ii) spacer DNA is covered by a uniform layer of proteins of unknown nature which, at very low salt concentrations (below 1 mM NaCl), can artificially give rise to the appearance of small granular particles of approximately nucleosome-like sizes. These particles, however, are different from nucleosomes in that they do not foreshorten the associated spacer DNA. The data support the concept of an altered nucleohistone conformation not only in transcribed chromatin but also in the vicinity of transcriptional events.},
  subject      = {Cytologie},
  language  = {en}
}
@article{Scheer1969,
  author    = {Scheer, Ulrich},
  title     = {Entwicklung der Gametogonien in ektopisch transplantierten Gonaden bei Triturus},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40510},
  year      = {1969},
  abstract  = {Nach homoplastischer Transplantation von larvalen Gonaden mit Fettkiirper in die vordere Leibeshiihle wiichst nur der Fettkiirper an der Leber an, so daB die Gonade nur indirekt mit dem Wirtsgewebe verbunden ist. Die Differenzierung der Gametogonien folgt der Normogenese, bei Ovartransplantationen entwickeln sich Auxocyten. Nach spatestens 27 Tagen ist die Blutversorgung wiederhergestellt. Homo- und autoplastische Transplantationen von Gonaden oh ne Fettkiirper ergeben fUr die Gametogonien eine vollig andere Entwicklung. Sind die Gonaden mit breiter Fliiche angewachsen, liiBt si ch bereits 7 Tage p.o. im Bereich der Kontaktzone Gonade-Leber die Karyolyse der Gametogonienkerne feststellen. Nach 3--4 Wochen stellt das Transplantat eine bindegewebige Zyste ohne Geschlechtszellen dar. Erythrozyten zeigen die Vaskularisation an. 1st nur ein Teil der Gonade mit der Leber verwachsen, zeigt der frei gebliebene Abschnitt eine normale Struktur mit Mitosen der Gametogonien. Die Degeneration der Geschlechtszellen hiingt offenbar von ihrer Lage zum extragonadalen Gewebe ab.},
  language  = {de}
}
@article{Scheer1986,
  author    = {Scheer, Ulrich},
  title     = {Injection of antibodies into the nucleus of amphibian oocytes: an experimental means of interfering with gene expression in the living cell},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41182},
  year      = {1986},
  abstract  = {No abstract available},
  language  = {en}
}
@article{Scheer2018,
  author    = {Scheer, Ulrich},
  title     = {Boveri's research at the Zoological Station Naples: Rediscovery of his original microscope slides at the University of W{\"u}rzburg},
  series = {Marine Genomics},
  volume    = {40},
  journal   = {Marine Genomics},
  doi       = {10.1016/j.margen.2018.01.003},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228453},
  pages     = {1-8},
  year      = {2018},
  abstract  = {Eric Davidson once wrote about Theodor Boveri: "From his own researches, and perhaps most important, his generalized interpretations, derive the paradigms that underlie modern inquiries into the genomic basis of embryogenesis" (Davidson, 1985). As luck would have it, the "primary data" of Boveri's experimental work, namely the microscope slides prepared by him and his wife Marcella during several stays at the Zoological Station in Naples (1901/02, 1911/12 and 1914), have survived at the University of Wurzburg. More than 600 slides exist and despite their age they are in a surprisingly good condition. The slides are labelled and dated in Boveri's handwriting and thus can be assigned to his published experimental work on sea urchin development. The results allowed Boveri to unravel the role of the cell nucleus and its chromosomes in development and inheritance. Here, I present an overview of the slides in the context of Boveri's work along with photographic images of selected specimens taken from the original slides. It is planned to examine the slides in more detail, take high-resolution focal image series of significant specimens and make them online available.},
  language  = {en}
}
@article{ScheerDabauvalleMerkertetal.1988,
  author    = {Scheer, Ulrich and Dabauvalle, Marie-Christine and Merkert, Hilde and Benavente, Ricardo},
  title     = {The nuclear envelope and the organization of the pore complexes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34275},
  year      = {1988},
  abstract  = {No abstract available},
  language  = {en}
}
@article{ScheerFranke1972,
  author    = {Scheer, Ulrich and Franke, Werner W.},
  title     = {Annulate lamellae in plant cells: formation during microsporogenesis and pollen development in Canna generalis Bailey},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32160},
  year      = {1972},
  abstract  = {The occurrence of stacked annulate tamellae is documented for a plant cell system, namely for pollen mother cells and developing pollen grains of Canna generalis. Their structural subarchiteeture and relationship to endoplasmie reticulum (ER) and nuclear envelope cisternae is described in detail. The results demonstrate structural homology between plant and animal annulate lamellae and are compatible with, though do not prove, the view that annulate lamcllar cisternae may originate as a degenerative form of endoplasmic retieulum.},
  language  = {en}
}
@article{ScheerFranke1969,
  author    = {Scheer, Ulrich and Franke, Werner W.},
  title     = {Negative staining and adenosine triphosphatase activity of annulate lamellae of newt oocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32087},
  year      = {1969},
  abstract  = {Semi -iso la ted annul a te lamellae were prepared from single newt oocy tes (Triturus alpestris) by a modified Call a n-T omlin technique. Such preparations were examined with the electron mi croscope, and the negative sta ining a ppearance of th e a nnulate lamellae is described . The annul a te lamellae can be de tected either adhering to the nuclear envelope or being detached from it. Sometimes they a re obse rved to be connected with slender tubular-like structures interpreted as pa rts of the endoplasmic reti culum. The results obta ined from negativ e sta ining a re combined with those from sections. Especially, the structural data on th e a nnula te lamellae and the nuclear envelope of the very same cell were compa red . Evidence is presented th a t in the oocytes studied the two kinds of porous cisternae, n amely a nnul a te lamellae and nuclear envelope, a re markedly distinguished in that the annul a te lamellae ex hibit a much higher pore frequency (generally about twice tha t found for the corresponding nuclear envelope) and have al so a rela tive pore area occupying as much as 32 \% to 55 \% of th e cistern al surface (compa red with 13 \% to 22 \% in the nuclear envelopes). T he pore di ame ter a nd all other ultras tructural details of the pore complexes, however, a re equi valent in both kinds of porous cisternae. Like the annuli of the nuclear pore complexes of various a nimal and pl ant cells, the a nnuli of the a nnula te lamellae pores reveal al so an eightfold symmetry of their subunits in negatively stained as well as in ectioned ma teria l. Furthermore, th e a nnul a te lamellae a re shown to be a site of activity of the Mg-Na-Kstimul a ted ATPase.},
  language  = {en}
}
@article{ScheerFrankeTrendelenburg1975,
  author    = {Scheer, Ulrich and Franke, Werner W. and Trendelenburg, Michael F.},
  title     = {Effects of actinomycin D on the association of newly formed ribonucleoproteins with the cistrons of ribosomal RNA in Triturus oocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32383},
  year      = {1975},
  abstract  = {No abstract available},
  language  = {en}
}