Über das Verhalten einiger Mosaikviren im geimpften Blatt im Anschluß an die Impfung

Ohne ZusammenfassungMit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Das Verhalten deutscher Kartoffelsorten gegenüber verschiedenen Stämmen des X-Virus im Pfropfversuch

Ohne Zusammenfassung     

Thoracophelia flabellifera n. sp., ein neuer sedentärer Polychät (Familie Opheliidae) in der Deutschen Bucht

Ohne ZusammenfassungMit 2 Abbildungen und 2 Tabellen     

Über schlauchförmige Ausstülpungen an der Zellmembran der Makrogametocyten von Eimeria perforans

Summary The surface of the gametocytes and gametes of Eimeria perforans reveals tube-like extrusions which have not been discovered so far in coccidia. These slender tubes are 650 Å in width and at least 1,3 in length. Probably they represent resorbing organelles. The tubes occur only at the surface of older female gametocytes and gametes and have not been observed in merozoites, schizonts, microgametocytes and male gametes. In transversal sections the tubes look like vesicles and are bordered by a membrane the layers of which are not sharply defined. The interior of the tubes seems to be empty after electron microscope observations. In longitudinal sections the membrane of the tubes is striated. The repeating unit of the dark and light bands amounts to about 165 Å. This appearance cannot be explained so far.

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Für beratende Hilfe sind wir Herrn Prof. Dr. R. Danneel und Herrn Prof. Dr. K. E. Wohlfarth-Bottermann zu Dank verpflichtet, für technische Unterstützung Fräulein cand. rer. nat. B. Volkmann. Herrn Dr. D. Spiecker von der Forschungsstelle für Jagdkunde und Wildschadenverhütung, Beuel, danken wir für die Durchführung der Infektionen. Die Mittel für die Untersuchungen stellte uns die Deutsche Forschungsgemeinschaft zur Verfügung.     

Persistence of DNA threads in human anaphase cells suggests late completion of sister chromatid decatenation

PICH (Plk1-interacting checkpoint helicase) was recently identified as an essential component of the spindle assembly checkpoint and shown to localize to kinetochores, inner centromeres, and thin threads connecting separating chromosomes even during anaphase. In this paper, we have used immuno-fiber fluorescence in situ hybridization and chromatin-immunoprecipitation to demonstrate that PICH associates with centromeric chromatin during anaphase. Furthermore, by careful analysis of PICH-positive anaphase threads through FISH as well as bromo-deoxyurdine and CREST labeling, we strengthen the evidence that these threads comprise mainly alphoid centromere deoxyribonucleic acid. Finally, by timing the addition of ICRF-193 (a specific inhibitor of topoisomerase-II alpha) to cells synchronized in anaphase, we demonstrate that topoisomerase activity is required specifically to resolve PICH-positive threads during anaphase (as opposed to being required to prevent the formation of such threads during earlier cell cycle stages). These data indicate that PICH associates with centromeres during anaphase and that most PICH-positive threads evolve from inner centromeres as these stretch in response to tension. Moreover, they show that topoisomerase activity is required during anaphase for the resolution of PICH-positive threads, implying that the complete separation of sister chromatids occurs later than previously assumed. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Wang and Schwarzbraun both contributed equally to this study.     

The lipidome and proteome of microsomes from the methylotrophic yeast Pichia pastoris

The methylotrophic yeast Pichia pastoris is a popular yeast expression system for the production of heterologous proteins in biotechnology. Interestingly, cell organelles which play an important role in this process have so far been insufficiently investigated. For this reason, we started a systematic approach to isolate and characterize organelles from P. pastoris. In this study, we present a procedure to isolate microsomal membranes at high purity. These samples represent endoplasmic reticulum (ER) fractions which were subjected to molecular analysis of lipids and proteins. Organelle lipidomics included a detailed analysis of glycerophospholipids, fatty acids, sterols and sphingolipids. The microsomal proteome analyzed by mass spectrometry identified typical proteins of the ER known from other cell types, especially Saccharomyces cerevisiae, but also a number of unassigned gene products. The lipidome and proteome analysis of P. pastoris microsomes are prerequisite for a better understanding of functions of this organelle and for modifying this compartment for biotechnological applications.