Der Insulinrezeptor in Aktion – wie Insulin seinen Rezeptor aktiviert(S. 485)
A fundamental question in signal transduction remains how the insulin receptor transmits signals upon ligand binding across the membrane. The overall architecture of the intact insulin receptor and its mode of activation have been controversially debated. Using a reconstitution approach, we were able to visualize the membrane-embedded full-length insulin receptors by electron microscopy demonstrating its activation mechanism.
Zusammenspiel von Sensoren und Transportern unter Nährstofflimitation(S. 488)
All living cells maintain cellular homeostasis to run biochemical reactions at constant speed. When certain nutrients become limiting, an interplay between sensors and transporters is required to restore cellular homeostasis. Here I will discuss several examples of how the cellular need for essential nutrients, such as lactose, pyruvate, and K+ is sensed and how the signals are transduced into the synthesis of the corresponding transporters.
Membrankomplexität und der Übergang vom Pro- zum Eukaryoten(S. 492)
Erik Hanspach, Simon Stockhorst, Sven B. Gould
Biological membranes are a crucial part of cellular life and they provide important insights into fundamental evolutionary questions. Studying membranes and their composition sheds light on the origin of life itself and how it diversified, and touches upon the origin of eukaryotes and their cellular compartments. Here, we discuss the impact of membranes and their associated proteins on evolutionary research and what that might tell us about the emergence of the eukaryotic cell.
Der Neandertaler in uns(S. 497)
When modern humans left Africa and started their endeavor to conquer the world ca. 60,000 years ago, they have met and admixed with other archaic humans such as Neandertals and Denisovans. The results of these admixtures can still be found in the genomes of present-day non- Africans, who carry about two percent of DNA in their genomes that is of Neandertal ancestry, and people in Oceania who carry additional about five percent of Denisovan DNA. These archaic remains still influence immunity, skin and hair morphology and behavioral phenotypes in present-day people.
Giftspritzen mit einzigartigem Injektionsmechanismus(S. 500)
Daniel Roderer, Stefan Raunser
Tc (toxin complex) toxins are virulence factors of many insect- and human-pathogenic bacteria. They are composed of three subunits that act together to perforate the host membrane using a syringe-like injection mechanism. Thereby they translocate toxic enzymes into the cell, resulting ultimately in the death of the host cell. Our recent high-resolution structural and functional data explain the mechanism of action of this type of bacterial toxins in molecular detail.
Eine Translokase für Makromoleküle in Mitochondrien von Trypanosomen(S. 504)
Mitochondrial protein import is mediated by complex machineries in the outer and inner membrane that have been studied in detail in yeast and mammals. Here we review our work of the corresponding machineries in the mitochondrion of Trypanosoma brucei. We conclude that the import machineries in the two systems are surprisingly different considering that they have the same functions. Moreover, we discuss the dual role the trypanosomal outer membrane translocase has in mitochondrial protein and tRNA import.
Vom Anfang und Ende der Systembiologie(S. 507)
The function of cells and thus the behaviour of molecular networks are dynamical systems. The end of systems biology is then either the happy acceptance of mathematical modelling in molecular and cell biology, or a lack of appreciation for the complexity of living systems. To understand mechanisms underlying cellular functions is a time and money consuming effort. So, why should we nevertheless take this route?
Proteine mit ausreichend Häm-Kofaktor beladen(S. 510)
Kerstin Fiege, Nicole Frankenberg-Dinkel
Heme proteins play an important role in several biological processes. For their functional analysis, recombinant proteins are widely used. However, the saturation of the proteins with the heme cofactor is often limited by the availability of heme inside the host cell. Several different methods to improve the recombinant production of heme proteins have been established, the most promising ones are being summarized here.
Mikrofluidische Einzelzelluntersuchungen mikrobieller Interaktionen(S. 515)
Alexander Grünberger, Alina Burmeister, Fabienne Hilgers
Interspecies interactions inside microbial communities bear a tremendous diversity of complex chemical processes that are by far not understood. For the investigation of these interactions, precise analytical tools are often missing. This article presents microfluidic single-cell tools that can be used for dynamic growth analysis of contact-based (here: horizontal gene transfer) and contact free (diffusive) interactions (here: L-lysine exchange) between microbial cells and colonies on single-cell level.
Automationslösungen für das Analytiklabor 2020(S. 520)
Kerstin Thurow, Thomas Roddelkopf
Automation solutions have meanwhile reached many areas of bioautomation and drug development. In contrast, the automation of analytical laboratories is still in its infancy. Due to the higher inhomogeneity of the samples and small analyte concentrations, higher sample amounts have to be handled. This requires the realization of suitable automation concepts for analytical laboratories as well as the development of special devices including automated opening/closing devices, filtration systems or tube handling systems.
RNAi-Screening in Knochenbildenden Zellen(S. 523)
Torsten Kroll, Mubashir Ahmad, Aspasia Ploubidou, Jan Tuckermann
Osteoporosis, the condition of decreased bone density resulting in bone porosity, brittleness, and a increased fracture risk is rising with aging. Current treatments slow-down bone loss but cannot increase bone formation and quality. Using osteoblasts – the bone forming cells – and RNAi libraries, we developed a high-content analysis approach which identified osteoblast modulators. Several among them are potential drug targets, to induce increase in bone formation thus efficiently combating osteoporosis.
Anwendungen & Produkte
Miniaturisierung von diagnostischen point-of-care-Plattformen(S. 538)
Molecular point-of-care (POC) testing is defined as the diagnostic testing of acute-care parameters at or close to the patients „bed side“ . The development of POC technologies and platforms aims to speed up diagnosis time to start targeted therapeutic treatments without a lag in time caused by the transport of samples to external laboratories as well as lengthy analytical methods. This article describes an enabling approach based on reversed purification of nucleic acids resulting in a fast sample analysis and a miniaturized disposable sample cartridge.
Vibrio natriegens – eine neue Plattform für die Biotechnologie?(S. 570)
Bastian Blombach, Felix Müller
High productivity is a crucial factor for biotechnological processes. Vibrio natriegens is the fastest growing non-pathogenic organism on our planet and therefore has the potential to speed-up industrial fermentation processes, cell free protein synthesis and routines in molecular biology.
Pilzliche Peroxygenasen: der Schlüssel zu C-H-Hydroxylierungen und mehr?(S. 572)
Martin J. Weissenborn, Pascal Püllmann
Fungal peroxygenases represent an exciting new enzyme class for stereo - selective hydroxylation reactions. They are capable of the oxyfunctionalisation of a large, diverse scope of substrates including alkanes and steroids as well as the heteroatoms sulfur and nitrogen. The outstanding activities and stabilities as well as their reliance on hydrogen peroxide as co-substrate renders it a highly interesting biocatalyst.