Hier finden Sie "Appetithäppchen" aus dem aktuellen BIOspektrum-Heft.
Wie Licht beim Aufbau von Geweben helfen kann(S. 362)
Marc Müller, Seraphine V. Wegner
Building tissues from cells as their basic building block is a promising approach in tissue engineering and allows assembling cells into microtissues with high precision, which is not possible with material-based approaches. The challenge lies in controlling when and where cells bind to each other. Using visible light as a trigger for cell-cell interactions provides the required spatiotemporal control without interfering with other cellular processes. This provides a new way to assemble multicellular structures with numerous potential applications in cell biology and regenerative medicine.
ESCRTs in Pflanzen: die Begleitung der Membranproteine zum Abbau(S. 366)
Marie-Kristin Nagel, Erika Isono
Insulin und sein Rezeptor – Spezifität durch Kombinatorik?(S. 369)
Theresia Gutmann, Ünal Coskun
Glucose homeostasis and growth essentially depend on insulin engaging its receptor. Combining biochemistry, structural biology, and molecular dynamics simulations, we demonstrated how insulin binding stabilizes the insulin receptor in a T-shaped conformation with up to four bound ligands: two at receptor site 1 and – for the first time – two at site 2. These findings expand the current models of insulin binding to its receptor and potentially inform new approaches to structure- guided drug design.
Tageszeitabhängige Körpertemperaturrhythmen regulieren die Genexpression(S. 372)
Marco Preußner, Florian Heyd
Alternative splicing is a dynamically regulated mechanism that dramatically increases the genomes coding capacity. Alternative splicing is regulated in a time-of-day dependent manner and depends on mammalian body temperature cycles. This observation let to the discovery of a body temperature sensitive kinase, which acts as sensor translating small changes in temperature (
Der Türkise Prachtgrundkärpfling – ein Leben im Zeitraffer(S. 375)
Johannes Krug, Annekatrin Richter, Hanna Reuter, Christoph Englert
Bakterien unter Stress – die stringent response(S. 378)
Wieland Steinchen, Gert Bange
The ability of microorganisms to cope with a large variety of environmental conditions is one of their most outstanding features. This review gives an overview over the metabolism and targets of ppGpp and pppGpp, the second messengers mediating resource allocation and adaptation to unfavourable conditions by triggering the ‘stringent response’.
Beweiskraft von DNA-Spuren: Was macht das Y-Chromosom so besonders?(S. 381)
Amke Caliebe, Michael Krawczak
Many crime cases require clarification whether or not a trace was left by a suspect. This is achieved by comparing their DNA profiles, a match indicating identity of suspect and donor. In sexual crimes, the trace is often a mixture of male and female material. This renders the analysis of the Y chromosome useful, but the interpretation of the genetic results is complicated by the specific mode of inheritance. We review some of the arising challenges as well as recently suggested solutions.
Wie ein rotierender Typ-IV-Pilus Archaeen das Schwimmen beibrachte(S. 385)
Sonja-Verena Albers, Patrick Tripp
Swimming motility in Archaea is mediated by the archaellum, a rotating type IV pilus. Archaellum-based motility is the only known way of active locomotion in Archaea to date. Here, we describe the way of how the archaellum was discovered to be a unique structure in nature and highlight the latest findings on archaellar components.
Visualisierung von Mutationen auf Einzelzellebene(S. 388)
Fabian M. Commichau, Alexander Grünberger, Sarah Täuber, Miriam Dormeyer
Bacterial mutations have been investigated since many years, but they remain difficult to observe directly in single cells, which limits the analysis of the underlying molecular mechanism. However, for the investigation of mutations at the level of single cells, precise analytical tools are currently developed. This article describes a workflow for visualizing mutations in single cells and lays the foundation for the quantification of bacterial mutation rates in the future.
Grundlagen und Mechanismen der Neocortex-Expansion(S. 393)
Wieland B. Huttner, Michael Heide
During primate, and notably human, evolution, the neocortex increased massively in size. This increase forms the basis of our higher cognitive abilities in comparison to other mammals. In recent years, major advances in understanding this evolutionary expansion have been achieved. Here, we would like to discuss the genetic foundation, principles and mechanisms underlying neocortical expansion.
Synthetische Hydrogele als 3D-Matrix für definierte Gewebemodelle(S. 398)
Ulrich Blache, Martin Ehrbar
Hydrogels are water-swollen polymer networks that are widely used as scaffold materials in 3D cell biology and tissue engineering. Biologists have commonly used hydrogels generated from natural extracellular matrix (ECM) polymers, which present challenges for biomedical applications due to their natural origin. Synthetic hydrogels are fabricated with fully defined material properties and can be modified to mimic the ECM. In this article, we discuss the design, recent applications and power of synthetic hydrogels for 3D tissue models.
Mikrophysiologisches Retinamodell als Alternative zu Tiermodellen(S. 402)
Johanna Chuchuy, Kevin Achberger, Stefan Liebau, Peter Loskill
The visual system is one of the most important human senses. Hence, blindness leads to an unimaginable reduction of life quality. However, most diseases leading to the loss of vision are still incurable, because current models used in ophthalmic research fail to recapitulate the human eye in many crucial aspects. Combining human retinal organoids with Organ-on-a-chip technology may lead to a paradigm shift in the way we study pathogenesis and treatment of retinal diseases.
Anwendungen & Produkte
Single-particle tracking von GPCRs(S. 414)
Caroline End, Sebastian Franken, Hendrik Bussmann, Erik Bonke
Single-particle tracking (SPT) is a method of high-resolution microscopy to investigate the dynamics of single molecules inside cells or on the cell surface. Here we describe for the first time the applicability of the HiBiT Protein Tagging System combined with the HaloTag® self-labeling protein technology for monitoring the lateral diffusion of a pharmacological relevant G protein-coupled receptor (GPCR) by SPT.
Multiklonale Antikörper als Ersatz für Zweitantikörper aus Seren(S. 416)
Stefan Dübel, Esther Veronika Wenzel, Giulio Russo
Today, recombinant antibodies can replace animal-derived primary antibodies in almost all applications. Due to their monoclonal origin and always known sequence, they offer optimal reproducibility. In contrast, almost all secondary antibodies are still made from animal sera. Multiclonal antibodies made by animal-free recombinant methods here offer a higher quality replacement for serum-derived secondary antibodies.
Loops und Tunnel: unterschätzte Elemente in Enzymen(S. 434)
Bernhard Hauer, Peter M. Heinemann, Lea R. Rapp
In enzymes, the active site is the location where substrates are chemically converted. If this site is deeply buried within the protein, substrates must pass not only through the body of the protein via a tunnel, but also flexible, site-decorating loops to access the active site. These elements can act as filters that influence on both substrate specificity and activity. Identifying and understanding how they exert such control has been of growing interest over the past several years.
Maßgeschneiderte Polyketidsynthasen zur Herstellung von Polyketid-Derivaten(S. 437)
Wolfgang Wohlleben, Ewa Musiol-Kroll
Polyketides (PKs) are secondary metabolites with valuable properties, including antibiotic, antifungal, antiviral, anticancer, and immunosuppressive activity. The biosynthesis of PKs is accomplished by multifunctional megaenzymes, the polyketide synthases (PKSs). The molecular architecture of those remarkable assembly lines provides opportunities for their engineering and generation of PK derivatives with potentially improved pharmacokinetics and/or expanded spectrum of bioactivity.