Schlafkrankheit bei deutschen Tropenreisenden

Zwei deutsche Tropenreisende erkrankten nach einer zweitägigen Safari im Akagera-Nationalpark in Ruanda an ostafrikanischer Trypanosomiasis (Schlafkrankheit). Leitsymptome waren Fieber, Lymphadenopathie und eine typische Primärläsion (Trypanosomenschanker). Die Diagnose konnte durch den Nachweis von Trypanosomen im peripheren Blut gesichert werden. Das Zentralnervensystem war in beiden Fällen nicht beteiligt. Unter dem Einfluß einer Therapie mit Suramin, 1 g pro Woche intravenös über 6 Wochen, bildeten sich die Symptome und die Parasitämie rasch zurück. Nach der Zahl der seit 1970 berichteten Fälle ergibt sich für deutsche Tropenreisende ein Infektionsrisiko von 0,3 pro 100 000. Aufgrund der teilweise erheblichen Wiederzunahme der Schlafkrankheit in einigen afrikanischen Ländern kann mit einer Zunahme des Infektionsrisikos auch für Touristen gerechnet werden

Microalgae production in fresh market wastewater and its utilization as a protein substitute in formulated fish feed for oreochromis spp.

Rapid growing of human population has led to increasing demand of aquaculture production. Oreochromis niloticus or known as tilapia is one of the most globally cultured freshwater fish due to its great adaptation towards extreme environment. Besides, farming of tilapia not only involves small scales farming for local consumption but also larger scales for international market which contributes to a foreign currency earning. Extensive use of fishmeal as feed for fish and for other animals indirectly caused an increasing depletion of the natural resource and may consequently cause economic and environmental unstable. Microalgae biomass seems to be a promising feedstock in aquaculture industry. It can be used for many purposes such as live food for fish larvae and dried microalgae to substitute protein material in fish feed. The microalgae replacement in fish feed formulation as protein alternative seem potentially beneficial for long term aqua-business sustainability. The present chapter discussed the potential of microalgae as an alternative nutrition in fish feed formulations, specifically Tilapia

Glycogen Synthase Kinase (GSK) 3β phosphorylates and protects nuclear myosin 1c from proteasome-mediated degradation to activate rDNA transcription in early G1 cells

Nuclear myosin 1c (NM1) mediates RNA polymerase I (pol I) transcription activation and cell cycle progression by facilitating PCAF-mediated H3K9 acetylation, but the molecular mechanism by which NM1 is regulated remains unclear. Here, we report that at early G1 the glycogen synthase kinase (GSK) 3β phosphorylates and stabilizes NM1, allowing for NM1 association with the chromatin. Genomic analysis by ChIP-Seq showed that this mechanism occurs on the rDNA as active GSK3β selectively occupies the gene. ChIP assays and transmission electron microscopy in GSK3β-/- mouse embryonic fibroblasts indicated that at G1 rRNA synthesis is suppressed due to decreased H3K9 acetylation leading to a chromatin state incompatible with transcription. We found that GSK3β directly phosphorylates the endogenous NM1 on a single serine residue (Ser-1020) located within the NM1 C-terminus. In G1 this phosphorylation event stabilizes NM1 and prevents NM1 polyubiquitination by the E3 ligase UBR5 and proteasome-mediated degradation. We conclude that GSK3β-mediated phosphorylation of NM1 is required for pol I transcription activation

Rab-GTPase binding effector protein 2 (RABEP2) is a primed substrate for Glycogen Synthase kinase-3 (GSK3)

Glycogen synthase kinase-3 (GSK3) regulates many physiological processes through phosphorylation of a diverse array of substrates. Inhibitors of GSK3 have been generated as potential therapies in several diseases, however the vital role GSK3 plays in cell biology makes the clinical use of GSK3 inhibitors potentially problematic. A clearer understanding of true physiological and pathophysiological substrates of GSK3 should provide opportunities for more selective, disease specific, manipulation of GSK3. To identify kinetically favourable substrates we performed a GSK3 substrate screen in heart tissue. Rab-GTPase binding effector protein 2 (RABEP2) was identified as a novel GSK3 substrate and GSK3 phosphorylation of RABEP2 at Ser200 was enhanced by prior phosphorylation at Ser204, fitting the known consensus sequence for GSK3 substrates. Both residues are phosphorylated in cells while only Ser200 phosphorylation is reduced following inhibition of GSK3. RABEP2 function was originally identified as a Rab5 binding protein. We did not observe co-localisation of RABEP2 and Rab5 in cells, while ectopic expression of RABEP2 had no effect on endosomal recycling. The work presented identifies RABEP2 as a novel primed substrate of GSK3, and thus a potential biomarker for GSK3 activity, but understanding how phosphorylation regulates RABEP2 function requires more information on physiological roles of RABEP2

Live Imaging of Xwnt5A-ROR2 Complexes

Secreted molecules of the Wnt family regulate key decisions in embryogenesis and adult tissue homeostasis by activating a complex network of Wnt signaling pathways. Although the different branches of Wnt signaling have been studied for more than 25 years, fluorophore tagged constructs for live cell imaging of Wnt molecules activating the Wnt/β-catenin pathway have become available only recently. We have generated a fluorophore tagged Wnt construct of the Xenopus Wnt5a protein (Xwnt5A) with the enhanced green fluorescent protein (EGFP), Xwnt5A-EGFP. This construct activates non-canonical Wnt pathways in an endocytosis dependent manner and is capable of compensating for the loss of endogenous Xwnt5A in Xenopus embryos. Strikingly, non-canonical Wnt pathway activation was restricted to short-range signaling while an inhibitory effect was observed in transwell cell cultures taken as long-range signaling model sytem. We used our Xwnt5A-EGFP construct to analyze in vivo binding of Wnt5A to its co-receptor ROR2 on the microscopic and on the molecular level. On the microscopic level, Xwnt5A-EGFP clusters in the membrane and recruits ROR2-mCherry to these clusters. Applying dual-colour dual-focus line-scanning fluorescence correlation spectroscopy on dorsal marginal zone explants, we identified membrane tethered Xwnt5A-EGFP molecules binding to ROR2-mCherry molecules. Our data favour a model, in which membrane-tethered Wnt-5A recruits ROR2 to form large ligand/receptor clusters and signals in an endocytosis-dependent manner