Über die morphologischen Veränderungen am menschlichen Ovar unter Einwirkung eines hormonalen Antikonzeptivums

Summary Under the effect of Anovlar®, which had been administered during two cycles, one Corpus luteum per cycle developed; characteristic of each was the thecahypoplasia. The typical epitheloid Theca interna cells were lacking in the Theca interna of the existing vesicular follicles. Theca interna growth in the atretic vesicular follicles could not be demonstrated.     

Praemia

Ohne Zusammenfassung     

Sequence and analysis of chromosome 2 of Dictyostelium discoideum

The genome of the lower eukaryote Dictyostelium discoideum comprises six chromosomes. Here we report the sequence of the largest, chromosome 2, which at 8 megabases (Mb) represents about 25% of the genome. Despite an A + T content of nearly 80%, the chromosome codes for 2,799 predicted protein coding genes and 73 transfer RNA genes. This gene density, about 1 gene per 2.6 kilobases (kb), is surpassed only by Saccharomyces cerevisiae (one per 2 kb) and is similar to that of Schizosaccharomyces pombe (one per 2.5 kb). If we assume that the other chromosomes have a similar gene density, we can expect around 11,000 genes in the D. discoideum genome. A significant number of the genes show higher similarities to genes of vertebrates than to those of other fully sequenced eukaryotes. This analysis strengthens the view that the evolutionary position of D. discoideum is located before the branching of metazoa and fungi but after the divergence of the plant kingdom, placing it close to the base of metazoan evolution.     

Elektronenmikroskopische Untersuchung am Übergangsepithel der Hausspitzmaus (Crocidura russula)

Summary The structure of the transitional epithelium of the common European white-toothed shrew (Crocidura russula) was examined by ultrathin serialsections. The epithelium consists of basal, intermediate and superficial cells. Basal and intermediate cells remain in contact with the basal lamina, whereas superficial cells have no connexion with the basal lamina.

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Herrn Prof. P. Vogel, Lausanne, danken wir für die Überlassung von Hausspitzmäusen aus seiner Zucht.     

Die Degenerationsraten präimplantierter Eier von Vitamin A-hyper- und avitaminotischen Ratten

Summary Comparing pre-implanted rat ova of animals suffering from Vitamin A deficiency or overdosage with normal ones, it was found that the amount of degenerated eggs was significantly higher in both the treated groups than in normal untreated animals. The mitotic stages of the segmentation steps prove to be highly sensitive to previous changes in the interior and exterior environment of the egg.