Hans Georg Schwarzacher

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The distribution of rDNA and the uptake of tritiated uridine was investigated in nucleoli of human Sertoli cells. The nucleolar components in these cells are spatially arranged in a highly ordered and invariable way and can be recognized in both light and electron microscopy. The pattern of distribution of rDNA and the pattern of uridine uptake in these(More)
Ag-staining of the nucleolus organizer region (NOR) was studied in the acrocentric chromosomes identified by Q-banding in repeated lymphocyte and skin fibroblast cultures from three different individuals. A similar pattern of Ag-stainability of NORs was found in the two tissues in each individual. Small differences concerning, in each case, only one of the(More)
The formation and development of nucleoli and their connections with the nucleolar chromosomes were studied in human spermatocytes using electron microscopy, silver staining of nucleolus organizer regions (NORs), high resolution autoradiography and in situ hybridization in order to localize rRNA genes and their transcription in the different stages of(More)
The distribution of the human ribosomal gene repeat within human Sertoli cell nucleoli was investigated with the help of DNA-DNA in situ hybridization at the light and electron microscopic level. Probes from both the transcribed part of the gene repeat and the "non-transcribed" spacer were found to hybridize predominantly to the dense fibrillar component of(More)
Electron micrographs reveal that the Ag-stainable substance is located on the outside of NOR's or around them but not in the chromosomes themselves. In association figures, the Ag-positive material lies between the acrocentric chromosomes. Light-microscopic studies show that the Ag stainability of the nucleolus in interphase is correlated with the function(More)
The distribution of 18S and 28S ribosomal RNA (rRNA), i.e. the chromosomal nucleolus organizer regions (NORs) was visualized in interphases and metaphases of non-stimulated and phytohemagglutinin (PHA)-stimulated human lymphocytes with a recently developed non-autoradiographic in situ hybridization method. This procedure involves mercurated RNA as a probe(More)
The distribution of ribosomal DNA (rDNA) in the nucleoli of human lymphocytes was revealed by in situ hybridization with a nonautoradiographic procedure at the electron microscopic level. rDNA is located in the dense fibrillar component of the nucleolus but not in the fibrillar centers. In the same cells the incorporation of tritiated uridine takes place in(More)
The distribution pattern of the transcribed and nontranscribed parts of human ribosomal RNA genes were visualized simultaneously in the same cells by nonautoradiographic in situ hybridization. DNA probes labeled with either digoxigenin or biotin were detected in the same cells by different fluorescence systems. The signals from both the transcribed and(More)
In the last few years numerous papers have been published on the nucleolus and its relation to the nucleolus organizer region (NOR). Several, even very recent, publications still reveal differences in the interpretation of these results. It is, however, our opinion that at the present state most of the observations on NORs and nucleoli can be interpreted so(More)