@article{ScheerTrendelenburgFranke1973, author = {Scheer, Ulrich and Trendelenburg, Michael F. and Franke, Werner W.}, title = {Transcription of ribosomal RNA cistrons: Correlation of morphological and biochemical data}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32195}, year = {1973}, abstract = {Electron microscopic spread preparations of oocyte nucleoli (lampbrush stage) of various amphibians are quantitatively evaluated and the length distributions of repeat-, matrix-, and spacer-units along the rRNA cistron containing axes are given. The correlation of the matrix unit data with the gel electrophoretic pattern of labelled nuclear RNA from the same oocytes is examined. The mean value of the matrix unit corresponds fairly well to a 2.6 million D peak of pre-rRNA but the distribution of both matrix units and labelled pre-rRNAs shows an asymmetrical heterogeneity indicating the existence of some larger primary transcription products of rDNA. Novel structural aspects are described in the spacer regions which suggest that transcription does also take place in DNP regions between the matrix units. A special "prelude piece" coding for approx. 0.5 million D of RNA is frequently visualized in the spacer segments at the beginning of a matrix unit. Possible artifacts resulting from the preparation, the relative congruence between the data obtained using both methods, and the functional meaning of the findings are discussed against the background of current concepts of structural organization and transcription products of nucleolar DNA.}, 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 10ยท 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{TrendelenburgScheerFranke1973, author = {Trendelenburg, Michael F. and Scheer, Ulrich and Franke, W. W.}, title = {Structural organization of the transcription of ribosomal DNA in oocytes of the house cricket}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33113}, year = {1973}, abstract = {No abstract available}, 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{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} } @inproceedings{TrendelenburgSpringScheeretal.1974, author = {Trendelenburg, Michael F. and Spring, Herbert and Scheer, Ulrich and Franke, Werner W.}, title = {Morphology of nucleolar cistrons in a plant cell, Acetabularia mediterranea}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32213}, year = {1974}, abstract = {The structural organization of transcriptionally active DNA that contains cistrons for precursor molecules of ribosomal RNA is described in positively stained spread preparations from nuclei and nucleoli isolated from the green alga, Acetabularia mediterranea Lmx. These nuclei contain large aggregates of nucleolar subunits in which fibril-covered regions, the putative active cistrons for precursors of ribosomal RNA, alternate with fibril-free intercepts, the "spacers". The length distribution of the different intercepts of this DNA is given, and the pattern is compared with those shown in animal cell systems. The data are discussed in relation to problems of transcription and of amplification of ribosomal RNA genes.}, language = {en} } @incollection{ScheerFranke1974, author = {Scheer, Ulrich and Franke, Werner W.}, title = {Structures and functions of the nuclear envelope}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39777}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1974}, abstract = {No abstract available}, subject = {Zellkern}, language = {en} } @article{FrankeBergerFalketal.1974, author = {Franke, Werner W. and Berger, S. and Falk, Heinz and Spring, H. and Scheer, Ulrich and Trendelenburg, Michael F. and Schweiger, H. G. and Herth, W.}, title = {Morphology of the nucleo-cytoplasmic interactions during the development of Acetabularia cells. I. The vegetative phase}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32363}, year = {1974}, abstract = {The ultrastructure of th e growin g and ma turing primary nucleus of Acetabularia medite rranea and Acetabularia major has been studied with the use of various fi xation procedures. Particular interest has been focused on the deta ils of the nuclear periphery and the perinuclear region. It is demonstrated that early in nuclear grow th a characteristic perinucl ear structura l complex is formed which is, among the eukaryotic cells, unique to Acetabularia and re lated genera. This perinuclear system consists essentially of a) the nuclear envelope with a very hi gh pore frequency and various pore complex assoc iat ion s w ith granular and/or threadlike structures some of which are continuous with the nucleolus; b) an approx imate ly 100 nm thick intermediate zone densely filled with a filam entOus material and occasional sma ll membraneous structures from which the typical cytOplasmic and nuclear organe lles and particles are excl ud ed ; c) an adjacent Iacunar labyrinthum which is interrupted by many plasmatic junction channels between the intermed iate zone and the free cytOplasm; d) numerous dense perinuclear bodies in the juxtanuclear cytOplasm which a re especia lly frequent at the junction channels and reveal a composition of aggregated fibrillar and granul ar structures; e) very dense exclusively fibrill ar agg regates which occur either in assoc iation with t he perinuclear region of the lacunar labyrinthum or, somewhat further out, in the cytOplasmic strands between the bra nches of the lacun ar labyrinthum in the form of slender, characteristic rods or "sausages".}, 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} } @inproceedings{FrankeScheer1974, author = {Franke, Werner W. and Scheer, Ulrich}, title = {Pathways of nucleocytoplasmic translocation of ribonucleoproteins}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33832}, year = {1974}, abstract = {No abstract available}, language = {en} } @article{SpringTrendelenbrugScheeretal.1974, author = {Spring, Herbert and Trendelenbrug, Michael F. and Scheer, Ulrich and Franke, Werner W. and Herth, Werner}, title = {Structural and biochemical studies of the primary nucleus of two green algal species, Acetabularia mediterranea and Acetabularia major}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40600}, year = {1974}, abstract = {Primary (giant) nuclei of the green algae Acetabularia mediterranea and A. major were studied by light and electron microscopy using in situ fixed material as well as manually isolated nuclear components. In addition, cytochemical reactions of nuclear structures and biochemical determinations of nuclear and cytoplasmic RNA and of genome DNA content were performed. The data obtained and the structures observed are interpreted as demonstralions of transcriptional activities of different gene classes. The most prominent class is the nucleolar cistrons of precursors of ribosomal RNA which occur highly repeated in clusters in the form of regularly alternating intercepts on deoxyribonucleoprotein axes of transcribed rDNA, the fibril-covered matrix units, and the fibril-free "spacer" segments. A description and a classification of the various structural complexes which seem to represent transcriptional activities is given. Quantitative evaluations of these arrangements are presented. The morphology and the dimensions of such structures are compared with the RNA molecular weight determinations and with the corresponding data reported from various animal cell systems. It is suggested that the formation of the giant nucleus is correlated with, and probably due to, an enormous amplification of transcriptionally active rDNA and packing of the extrachromosomal copies into the large nucleolar aggregate bodies.}, subject = {Cytologie}, language = {en} } @article{FrankeJaraschHerthetal.1975, author = {Franke, Werner W. and Jarasch, Ernst-Dieter and Herth, Werner and Scheer, Ulrich and Zerban, Heide}, title = {Cytology : general and molecular cytology}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41458}, year = {1975}, abstract = {The present review discusses some general aspects of membrane structure and problems of membrane isolation and membrane biochemistry, with particular focus on the endoplasmic reticulum.}, subject = {Botanik}, 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{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} } @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{EckertFrankeScheer1975, author = {Eckert, W. A. and Franke, Werner W. and Scheer, Ulrich}, title = {Nucleocytoplasmic translocation of RNA in Tetrahymena pyriformis and its inhibition by actinomycin D and cycloheximide}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32399}, year = {1975}, abstract = {No abstract available}, language = {en} } @article{SpringScheerFrankeetal.1975, author = {Spring, Herbert and Scheer, Ulrich and Franke, Werner W. and Trendelenburg, Michael F.}, title = {Lampbrush type chromosomes in the primary nucleus of the green alga Acetabularia mediterranea}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32370}, year = {1975}, abstract = {No abstract available}, language = {en} } @article{ZentgrafScheerFranke1975, author = {Zentgraf, Hanswalter and Scheer, Ulrich and Franke, Werner W.}, title = {Characterization and localization of the RNA synthesized in mature avian erythrocytes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32410}, year = {1975}, abstract = {No abstract available}, language = {en} } @inproceedings{TrendelenburgFrankeSpringetal.1975, author = {Trendelenburg, M. F. and Franke, Werner W. and Spring, H. and Scheer, Ulrich}, title = {Ultrastructure of transcription in the nucleoli of the green algae Acetabularia major and A. mediterranea}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33779}, year = {1975}, abstract = {No abstract available}, language = {en} } @inproceedings{FrankeScheer1975, author = {Franke, Werner W. and Scheer, Ulrich}, title = {Biochemical and structural aspects of nucleocytoplasmic transfer of ribonucleoproteins at the nuclear envelope level: facts and theses}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33766}, year = {1975}, abstract = {No abstract available}, language = {en} }