Pattern of epithelial cell cycling in hydra

We have investigated the spatial pattern of epithelial cell cycling in a mutant strain of Hydra magnipapillata (sf-1). This strain has temperature sensitive interstitial stem cells and thus polyps containing only epithelial cells can be obtained by growth at the restrictive temperature. Epithelial animals were pulse labeled with the thymidine analog 5′-bromo-2′-deoxyuridine (Brdu) and stained with anti-Brdu antibody to visualize S phase cells. Our results indicate that Brdu-labeled cells are broadly and fairly evenly distributed along the body column. Feeding stimulates a rapid decrease and then an increase in labeled cells in gastric tissue; labeled cells in the head are not affected. Starvation leads to a twofold decrease in labeled cells in the gastric region; the density of labeled cells in head tissue remains similar to that in well-fed animals. During bud formation the number of labeled epithelial cells increases significantly in the evaginating bud. During head regeneration the number of labeled cells declines sharply during the first 12 hr and then increases to a density typical of head tissue by 24–36 hr of regeneration. The results indicate the release of signals by feeding and regeneration which inhibit mitosis. By contrast head tissue and developing buds express signals stimulating mitosis. Thus changes in epithelial cell cycling in hydra are closely correlated with morphogenetic events as well as with feeding stimuli

Phänomenologie und Bekämpfung von "Cyberpiraterie" : eine kriminologische und kriminalpolitische Analyse

Illegale Beschaffung und Distribution von Schutzgegenständen geistigen Eigentums über das Internet haben sich spätestens seit dem Siegeszug der sogenannten Online-Tauschbörsen (P2P-Filesharing-Systeme) zu einem regelrechten Massenphänomen entwickelt. Die vorliegende Arbeit untersucht die vielfältigen Tatbegehungsmodalitäten, die Täterstruktur und -motivation, die Auswirkungen von Cyberpiraterie sowie Bekämpfungs- und Überwachungsstrategien bezüglich des Problems. Neben einer kritischen Beurteilung der strafrechtlichen Situation enthält die Arbeit auch eigene Lösungsvorschläge.Die Dissertation gliedert sich in drei Teile: Der erste Teil enthält eine Einführung, in der auch die wichtigsten technischen Zusammenhänge erläutert werden. Teil 2 beschäftigt sich mit der ältesten Form digitaler Piraterie, der Softwarepiraterie (auch: ‘Warez-Szene’). Teil 3 schließlich behandelt das recht neue Phänomen der Online-Musikpiraterie (‘MP3-Szene’).Angesichts der starken Dynamik des Themenkreises ist bei der Wahl der Bekämpfungsstrategien stets die aktuelle digitale Realität zu berücksichtigen. Der Wahlspruch der Verwertungsgesellschaften, wonach ‘das Schützbare zu schützen und das Nicht-Schützbare zu vergüten’ ist, scheidet in diesem Zusammenhang die Geister. Während die Vertreter der Unterhaltungsindustrie sämtliche digitalen Werke für schützbar erklären, zeigt die vorliegende Arbeit exemplarisch auf, dass ein umfassender Schutz digitaler Inhalte im Internet zur Zeit weder rechtlich noch technisch durchsetzbar ist. Nicht nur aus diesem Grund sondern auch aus rechtspolitischen und kriminologischen Erwägungen ist es dringend geboten, zivilrechtliche Alternativen zu dem derzeit eingeschlagenen, strafrechtlichen Weg zu etablieren

STAP-2 Negatively Regulates both Canonical and Noncanonical NF-κB Activation Induced by Epstein-Barr Virus-Derived Latent Membrane Protein 1▿

The signal-transducing adaptor protein 2 (STAP-2) is a recently identified adaptor protein that contains a pleckstrin homology (PH) and Src homology 2 (SH2)-like domains, as well as a proline-rich domain in its C-terminal region. In previous studies, we demonstrated that STAP-2 binds to MyD88 and IKK-α or IKK-β and modulates NF-κB signaling in macrophages. In the present study, we found that ectopic expression of STAP-2 inhibited Epstein-Barr virus (EBV) LMP1-mediated NF-κB signaling and interleukin-6 expression. Indeed, STAP-2 associated with LMP1 through its PH and SH2-like domains, and these proteins interacted with each other in EBV-positive human B cells. We found, furthermore, that STAP-2 regulated LMP1-mediated NF-κB signaling through direct or indirect interactions with the tumor necrosis factor receptor (TNFR)-associated factor 3 (TRAF3) and TNFR-associated death domain (TRADD) proteins. STAP-2 mRNA was induced by the expression of LMP1 in human B cells. Furthermore, transient expression of STAP-2 in EBV-positive human B cells decreased cell growth. Finally, STAP-2 knockout mouse embryonic fibroblasts showed enhanced LMP1-induced cell growth. These results suggest that STAP-2 acts as an endogenous negative regulator of EBV LMP1-mediated signaling through TRAF3 and TRADD

Live-cell imaging of receptors around postsynaptic membranes.

This protocol describes how to image the trafficking of glutamate receptors around excitatory postsynaptic membrane formed on an adhesion protein-coated glass surface. The protocol was developed to clarify how receptors move during the induction of synaptic plasticity. Dissociated neurons are cultured on a coverslip coated with neurexin, which induces the formation of postsynaptic membrane-like structures on the glass surface. A glutamate receptor tagged with a fluorescent protein is then transfected into neurons, and it is observed with total internal reflection fluorescence microscopy. The whole process takes about 3 weeks. Changes in the amount of cell-surface receptors caused by neuronal activities can be quantified, and individual exocytosis events of receptors can be clearly observed around the pseudo-postsynaptic membrane. This protocol has potential applications for studies of movements of membrane proteins around other specialized regions of the cell membrane, such as the inhibitory postsynaptic membrane, the presynaptic membrane or the immunological synapses