@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}
}
@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}
}
@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{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}
}