Rational design of a small molecule-responsive intramer controlling transgene expression in mammalian cells

Aptamers binding proteins or small molecules have been shown to be versatile and powerful building blocks for the construction of artificial genetic switches. In this study, we present a novel aptamer-based construct regulating the Tet Off system in a tetracycline-independent manner thus achieving control of transgene expression. For this purpose, a TetR protein-inhibiting aptamer was engineered for use in mammalian cells, enabling the RNA-responsive control of the tetracycline-dependent transactivator (tTA). By rationally attaching the theophylline aptamer as a sensor, the inhibitory TetR aptamer and thus tTA activity became dependent on the ligand of the sensor aptamer. Addition of the small molecule theophylline resulted in enhanced binding to the corresponding protein in vitro and in inhibition of reporter gene expression in mammalian cell lines. By using aptamers as adaptors in order to control protein activity by a predetermined small molecule, we present a simple and straightforward approach for future applications in the field of Chemical Biology. Moreover, aptamer-based control of the widely used Tet system introduces a new layer of regulation thereby facilitating the construction of more complex gene network

Rose Ausländer, "Gedichte", poemas

Traduzido por Irene Aro

On tangibility, contemporary reliefs and continuous dimensions

I am a relief maker, who proposes "worldmaking" as a paradigm for works of art. The relief, whether it is an art category or a geological section, is a space that extends from the surface to the volume. Such a space is as tangible as it is visible. The notion of tangibility is paramount for making and receiving artworks commonly known as relief sculptures. My thesis examines my practice by establishing the territories of my artworks. Triggered by personal encounters and perceptions, each of these is a case study forming a section in my analysis. My purpose is to contextualise and underscore my practice, in a pragmatic rather than theoretical investigation. The public art commission Ways of Worldmaking raises my main questions. These relate to the topographical interconnectivity across the surface of the earth. The use of the books as a collection and an archive is another layer developed further in my concluding artwork Ways of Worldmaking / Self-portrait, that is, my thesis bibliography turned into a sculpture. My making of reliefs responds to sculptural and material dimensions of site specificity while examining its social and political features. Relief is an overlooked category of practice. It is a metaphor for observation, with qualities of elevation and depth and a variety of thickness that highlights notions of discovery and emergence of meaning. The history of Western relief sculpture informs my study of contemporary pieces. These articulate several sets of dimensions continuously from recessed parts to more protuberant ones. There is a tension between the desire to touch and the frustration of that same desire expressed particularly clearly in relief. I observe that dialectic through the senses of tactile touch and optical touch. Artists are constantly creating and exhibiting reliefs, but they rarely make full use of the physical complexity and the epistemological potential of this form of art. Relief making seems to me an interesting way of expressing our distance from or our relationship with the landforms, either theoretically or practically. Although the idea of category remains questionable in itself, I make textured world-versions, promote the relief as a rich space, readdress and redress its position among sculpture and painting

Semi-solid wire-feed additive manufacturing of AlSi7Mg by direct induction heating

In this study, a novel process is presented in which direct induction heating with frequencies in the MHz range is used for the wire-feed additive manufacturing of the alloy AlSi7Mg. The high frequency of 1.5 MHz enables processing of 1.2 mm diameter wires without the need for indirect heating via a nozzle. The feasibility of the process is proven by the experimental identification of a proper process window regarding the influential parameters such as the distance between inductor and substrate, induction power and wire feed rate for the fabrication of single layers. Furthermore, a strategy for the successful fabrication of multi-layered cubes is developed. The microstructure of the cubes exhibits a characteristic variation along the build direction. Micro-computed tomography is used to reveal defects like lack of fusion and spherical pores in test cubes. The presented results are used to derive possible process improvements, which will allow the novel process to be used as a fast and powder-free alternative metal additive manufacturing route in future

Development and Characterization of a Monoclonal Antibody against Ochratoxin B and Its Application in ELISA

A monoclonal antibody specific to ochratoxin B (OTB) was employed for the development of an indirect competitive OTB-ELISA. The optimized OTB-ELISA resulted in a limit of detection (LOD) for OTB of 3 µg/L (8 nM), a limit of quantification (LOQ) of 3.7 µg/L (10 nM), and a 50% inhibitory concentration (IC50) of 150 nM. Due to very low cross-reactivity to OTA (2.7%) and structurally related molecules (0%), this OTB-ELISA was found to be suitable to detect OTB with excellent precision in different matrices, i.e., beer, coffee and wine. Therefore, this OTB-ELISA will allow screening of OTB in food and feed products

Rapid, modular and reliable construction of complex mammalian gene circuits

We developed a framework for quick and reliable construction of complex gene circuits for genetically engineering mammalian cells. Our hierarchical framework is based on a novel nucleotide addressing system for defining the position of each part in an overall circuit. With this framework, we demonstrate construction of synthetic gene circuits of up to 64 kb in size comprising 11 transcription units and 33 basic parts. We show robust gene expression control of multiple transcription units by small molecule inducers in human cells with transient transfection and stable chromosomal integration of these circuits. This framework enables development of complex gene circuits for engineering mammalian cells with unprecedented speed, reliability and scalability and should have broad applicability in a variety of areas including mammalian cell fermentation, cell fate reprogramming and cell-based assays.Synthetic Biology Engineering Research Center (SA5284-11210)United States. Defense Advanced Research Projects Agency (HR0011-12-C-0067)United States. Defense Advanced Research Projects Agency (DARPA-BAA-11-23)National Science Foundation (U.S.) (CBET-0939511)National Institutes of Health (U.S.). (5-R01-CA155320-02