Refine
Has Fulltext
- yes (61)
Is part of the Bibliography
- yes (61)
Year of publication
Document Type
- Journal article (48)
- Conference Proceeding (8)
- Book article / Book chapter (4)
- Book (1)
Language
- English (61) (remove)
Keywords
- Cytologie (7)
- Botanik (2)
- electron microscopy (2)
- transcription (2)
- Acetabularia (1)
- Actinomycin D (1)
- Amphibian oocytes (1)
- Anatomie (1)
- Chromatin structure (1)
- Cross-bridges (1)
- DNA antibodies (1)
- DNA immunolocalization (1)
- Deutschland (1)
- Electron microscopy (1)
- Gefäßpflanzen (1)
- Golgi apparatus (1)
- Membranes (1)
- Microtubules (1)
- Nuclear pores (1)
- Nucleocytoplasmic exchange (1)
- Nucleolus (1)
- Tetrahymena (1)
- Tumor / Zellteilung (1)
- Verzeichnis (1)
- Zelldifferenzierung (1)
- Zellkern (1)
- antibody (1)
- chromatin (1)
- evolution (1)
- gene activity (1)
- immunofluorescence (1)
- monoclonal antibodies (1)
- mycoplasma tests (1)
- nucleosomes (1)
- ribosomal RNA genes; electron microscopy; spread preparations (1)
- ribosomes (1)
- sperm (1)
Institute
- Theodor-Boveri-Institut für Biowissenschaften (61) (remove)
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.