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The structure of ribosomal chromatin in exponentially growing Friend cells, in stationary cells, and in metaphase chromosomes was studied by psoralen photocrosslinking. It is shown that in intact cells, two distinct types of ribosomal chromatin coexist in Friend cells, one that contains nucleosomes and represents the inactive copies and one that lacks a(More)
Recently, we showed for the wastewater of a large Swiss university hospital that primary DNA damage, assessed by a bacterial SOS repair assay (umuC test), could be largely assigned to a specific class of antibiotics, the fluoroquinolones (FQs) (Hartmann et al. [1998] Environ Toxicol Chem 17:377-382). In an attempt to confirm the significance of FQs for the(More)
The genotoxic potential of the waste water of a hospital was evaluated by the umuC test. Within 2 years over 800 native waste water samples were analysed. Genotoxic activity was found in 13% of the samples. The highest genotoxic activity occurred in the morning hours, but genotoxic samples were detected also during the day and at night. 96% of the genotoxic(More)
The photoelectric aerosol sensor (PAS) is a technique suitable for on-line monitoring of particle-bound polycyclic aromatic hydrocarbons (PPAHs). Although this is a very fast and inexpensive technique, it does not measure individual PAH species but gives a measure of the total amount of PPAHs. Because of the suitability of this sensor for air-pollution(More)
Trimethylpsoralen was used to crosslink the extrachromosomal ribosomal DNA in nucleoli or nuclei of growing Dictyostelium discoideum cells. The DNA was extracted and was examined by spreading under denaturing conditions for electron microscopy. Intact 95,000 base ribosomal DNA molecules were seen, showing regularly spaced, single-stranded bubbles of about(More)
To ease and speed up the translation of the ICNP version 1 into the German language a web service was developed to support the collaborative work of all Austrian, Swiss, and German translators and subsequently of the evaluators of the resultant translation. The web service does help to support a modified Delphi technique. Since the web service is(More)
Balbiani ring 2 (BR2) in salivary glands of Chironomus pallidivittatus and C. tentans (two sibling species of the subgenus Camptochironomus) is a favoured model system for studies of gene organization and transcript formation. Here we show that BR2 is more complex than hitherto believed, containing two 75S RNA-producing genes, BR2a and BR2b, present in(More)
We present a plasmid rescue from transgenic Drosophila to study spontaneous and mutagen-induced mutations in vivo. Transgenic Drosophila lines were established by transformation with a shuttle vector containing the bacterial lacZ gene as a target for mutagenesis. The target gene can be recovered into bacteria by restriction endonuclease treatment of total(More)