TY  - JOUR
A1  - Franke, Werner W.
A1  - Berger, S.
A1  - Falk, Heinz
A1  - Spring, H.
A1  - Scheer, Ulrich
A1  - Trendelenburg, Michael F.
A1  - Schweiger, H. G.
A1  - Herth, W.
T1  - Morphology of the nucleo-cytoplasmic interactions during the development of Acetabularia cells. I. The vegetative phase
N2  - 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".
Y1  - 1974
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32363
ER  - 
TY  - CHAP
A1  - Trendelenburg, Michael F.
A1  - Spring, Herbert
A1  - Scheer, Ulrich
A1  - Franke, Werner W.
T1  - Morphology of nucleolar cistrons in a plant cell, Acetabularia mediterranea
N2  - 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.
KW  - ribosomal RNA genes; electron microscopy; spread preparations
Y1  - 1974
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32213
ER  -