Bohme K.,TU Braunschweig
Expression of all Yersinia pathogenicity factors encoded on the virulence plasmid, including the yop effector and the ysc type III secretion genes, is controlled by the transcriptional activator LcrF in response to temperature. Here, we show that a protein- and RNA-dependent hierarchy of thermosensors induce LcrF synthesis at body temperature. Thermally regulated transcription of lcrF is modest and mediated by the thermo-sensitive modulator YmoA, which represses transcription from a single promoter located far upstream of the yscW-lcrF operon at moderate temperatures. The transcriptional response is complemented by a second layer of temperature-control induced by a unique cis-acting RNA element located within the intergenic region of the yscW-lcrF transcript. Structure probing demonstrated that this region forms a secondary structure composed of two stemloops at 25°C. The second hairpin sequesters the lcrF ribosomal binding site by a stretch of four uracils. Opening of this structure was favored at 37°C and permitted ribosome binding at host body temperature. Our study further provides experimental evidence for the biological relevance of an RNA thermometer in an animal model. Following oral infections in mice, we found that two different Y. pseudotuberculosis patient isolates expressing a stabilized thermometer variant were strongly reduced in their ability to disseminate into the Peyer's patches, liver and spleen and have fully lost their lethality. Intriguingly, Yersinia strains with a destabilized version of the thermosensor were attenuated or exhibited a similar, but not a higher mortality. This illustrates that the RNA thermometer is the decisive control element providing just the appropriate amounts of LcrF protein for optimal infection efficiency. Source
Schroder U.,TU Braunschweig
Angewandte Chemie - International Edition
Insects and molluscs as future biological drones for military purposes or environmental monitoring systems (see picture)? Two research groups have demonstrated the successful implantation and operation of biofuel cells in snails, clams, and cockroaches. Owing to their simple circulatory systems, these invertebrates could be used in implantation studies without serious physical damage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Hopf H.,TU Braunschweig
Angewandte Chemie - International Edition
Antimatter: Once studied primarily for their antiaromatic properties, pentalenes are rapidly becoming important π-systems for novel electronic materials (see scheme). Recent developments in this area are summarized. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
TU Braunschweig | Date: 2013-03-12
The present invention relates generally to signal enhancement in single-molecule-assays. In particular, the present invention relates to an array allowing signal enhancement of single molecules. The assay is in particular a Bioassay allowing single molecule analysis of biomolecules. Preferably, the signal enhancement is a fluorescence enhancement based on optical antenna. In another aspect, the present invention relates to a method for measuring irradiation of electromagnetic waves of single compounds. Based on the arrays and methods, it is possible to allow signal enhancement and, consequently, allow single molecule assays with high sensitivity and reproducibility.
TU Braunschweig | Date: 2015-04-16
Positioning structures in at least one indentation present on a or in a support, wherein said indentation is an indentation having a diameter in the nanometer range, makes it possible to position the structure in the indentation substantially centrally with defined orientation. A support having at least one indentation, wherein this is one having a size in the nanometer range, includes a predetermined structure which is arranged substantially centrally within said indentation and which optionally has a functional unit diametrically opposite to the side pointing to the bottom surface. The arrangement is especially suitable for single molecule analysis and, here especially, for single molecule sequencing and other high-throughput methods.