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Cavallari M.,University of Basel | Cavallari M.,Whitehead Institute For Biomedical Research | Stallforth P.,Max Planck Institute of Colloids and Interfaces | Stallforth P.,Leibniz Institute for Natural Product Research and Infection Biology | And 11 more authors.
Nature Chemical Biology | Year: 2014

Severe forms of pneumococcal meningitis, bacteraemia and pneumonia result in more than 1 million deaths each year despite the widespread introduction of carbohydrate-protein conjugate vaccines against Streptococcus pneumoniae. Here we describe a new and highly efficient antipneumococcal vaccine design based on synthetic conjugation of S. pneumoniae capsule polysaccharides to the potent lipid antigen a-galactosylceramide, which stimulates invariant natural killer T (iNKT) cells when presented by the nonpolymorphic antigen-presenting molecule CD1d. Mice injected with the new lipid-carbohydrate conjugate vaccine produced high-affinity IgG antibodies specific for pneumococcal polysaccharides. Vaccination stimulated germinal center formation; accumulation of iNKT cells with a T follicular helper cell phenotype; and increased frequency of carbohydrate-specific, long-lived memory B cells and plasmablasts. This new lipid-carbohydrate vaccination strategy induced potent antipolysaccharide immunity that protected against pneumococcal disease in mice and may also prove effective for the design of carbohydrate-based vaccines against other major bacterial pathogens. © 2014 Nature America, Inc. All rights reserved.

Broker P.,University of Potsdam | Lucke K.,GILUPI GmbH | Perpeet M.,SAW Instruments | Gronewold T.M.A.,SAW Instruments
Sensors and Actuators, B: Chemical | Year: 2012

A nanostructured chip surface was fabricated enabling binding via spaced antibodies specifically targeting surface proteins of cancer cells and detection of extremely low numbers of circulating tumor cells (CTC) without labeling using a sam ® 5 biosensor. The antibody surfaces mostly were generated by self assembly of antibodies to gold nanospots on the sensitive SiO 2-surface of a sam ® 5 chip. Compared with a complete gold surface, only 40% of the amount of antibodies was bound to the nanospot surface, but structured such that 15-fold higher sensitivity to vital cancer cells was achieved. Human cancer cell lines JEG-3 (lymphoblastic leukemia) and MOLT-17 (placental choriocarcinoma) from cell cultures were successfully detected. The sensor showed significant responses on less than 10 cells injected in a single run. The extreme increase in sensitivity and its simple regeneration emphasizes the usefulness of its introduction in biomedical applications. © 2012 Elsevier B.V. All rights reserved.

Blasche S.,German Cancer Research Center | Mortl M.,Proteros biostructures | Steuber H.,Proteros biostructures | Steuber H.,University of Marburg | And 13 more authors.
PLoS ONE | Year: 2013

Enterohemorrhagic and enteropathogenic E. coli (EHEC and EPEC) can cause severe and potentially life-threatening infections. Their pathogenicity is mediated by at least 40 effector proteins which they inject into their host cells by a type-III secretion system leading to the subversion of several cellular pathways. However, the molecular function of several effectors remains unknown, even though they contribute to virulence. Here we show that one of them, NleF, binds to caspase-4, -8, and -9 in yeast two-hybrid, LUMIER, and direct interaction assays. NleF inhibits the catalytic activity of the caspases in vitro and in cell lysate and prevents apoptosis in HeLa and Caco-2 cells. We have solved the crystal structure of the caspase-9/NleF complex which shows that NleF uses a novel mode of caspase inhibition, involving the insertion of the carboxy-terminus of NleF into the active site of the protease. In conformance with our structural model, mutagenized NleF with truncated or elongated carboxy-termini revealed a complete loss in caspase binding and apoptosis inhibition. Evasion of apoptosis helps pathogenic E. coli and other pathogens to take over the host cell by counteracting the cell's ability to self-destruct upon infection. Recently, two other effector proteins, namely NleD and NleH, were shown to interfere with apoptosis. Even though NleF is not the only effector protein capable of apoptosis inhibition, direct inhibition of caspases by bacterial effectors has not been reported to date. Also unique so far is its mode of inhibition that resembles the one obtained for synthetic peptide-type inhibitors and as such deviates substantially from previously reported caspase-9 inhibitors such as the BIR3 domain of XIAP. © 2013 Blasche et al.

Cui J.,Max Planck Institute for Polymer Research | Iturri J.,Max Planck Institute for Polymer Research | Gotz U.,SAW Instruments | Jimenez M.,SAW Instruments | Del Campo A.,Max Planck Institute for Polymer Research
Langmuir | Year: 2013

The Surface Acoustic Wave (SAW) technique is applied for the first time to quantify the properties of a responsive polymer brush layer. Using a single SAW chip, the response of five different brush compositions to several pH changes was monitored in parallel in a single run. These results were compared with QCM-D studies on the same system. SAW exhibited two remarkable advantages against QCM-D: (i) multiplexing capability, which allowed considerable reduction in experimental time and expenses (1/8 reduction of experimental time, 1/5 in the number of chips, and 1/10 in solvent consumption in our case), and (ii) higher sensitivity in both mass and viscosity change than QCM-D (4-5 times higher in our systems). Our results demonstrate the suitability and advantages of the SAW technology for application in polymer science, in particular for the study of the compositional effects in responsive thin layers. © 2013 American Chemical Society.

Klumpers F.,Ruhr University Bochum | Gotz U.,SAW Instruments | Kurtz T.,SAW Instruments | Herrmann C.,Ruhr University Bochum | Gronewold T.M.A.,SAW Instruments
Sensors and Actuators, B: Chemical | Year: 2014

The specific interaction between small GTP binding protein Ras and its effector proteins is a typical example how cellular signal transduction is executed. The binding properties of the effector Nore1A to active K-Ras-GppNHp and to inactive K-Ras-GDP were analyzed with a label-free surface acoustic wave (SAW) sensor. The measured phase signal was used for the concomitant evaluation of the binding kinetics. Binding was observed only to the active K-Ras-GppNHp complex. An affinity decrease based on an increase in ionic strength was detected from the calculated KD's in the range of 6.6 × 10 -8 M in 100 mM NaCl and of 1.1 × 10-6 M in 500 mM NaCl. The recorded amplitude signal was used as a measure of the conformational changes. It could be shown that at 100 mM NaCl, the interaction causes an increase in rigidity. At 500 mM NaCl, no increase in rigidity was measured at high concentrations of Nore1A due to reduced binding, suggesting an influence of salt on protein rigidity and hence on the strength of binding. © 2014 Elsevier B.V.

Bortolini C.,The Interdisciplinary Center | Bortolini C.,CAS National Center for Nanoscience and Technology | Liu L.,The Interdisciplinary Center | Liu L.,Jiangsu University | And 4 more authors.
Soft Matter | Year: 2014

The final structure and properties of synthetic peptides mainly depend on their sequence composition and experimental conditions. This work demonstrates that a variation in the positions of hydrophobic residues within a peptide sequence can tune the self-assembly. Techniques employed are atomic force microscopy, transmission electron microscopy and an innovative method based on surface acoustic waves. In addition, a systematic investigation on pH dependence was carried out by utilizing constant experimental parameters. © the Partner Organisations 2014.

The present invention relates to improved sensor units, apparatuses that include and components of said sensor units. Further, the present invention also relates to methods, uses and processes involving the foregoing aspects. The improved sensor units may, in particular, include a surface acoustic wave (SAW) sensor region. The sensor units of the invention have improved characteristics over prior art sensor units, for example a reduced propensity for bubbles or other obstacles to be retained within the sensor unit, and in particular on the sensor region, thereby providing sensor units that show improved performance such as in terms of sensitivity, accuracy, stability, reliability and/or reproducibility in detection assays.

The present invention relates to improved microfluidic devices, apparatuses that include, and components of, said microfluidic devices. Further, the present invention also relates to methods involving the foregoing. The improved microfluidic devices may, in particular, include a surface acoustic wave (SAW) sensor as the sample region to which a sample liquid is exposed. The microfluidic devices of this invention provide a simple and flexible solution to one or more problems of prior art microfluidic devices, for example enabling one or more subsets of a plurality of sample regions to be exposed, such as in a selective and/or predetermined manner, to one or more sample liquids. Such functionality has particular advantages for the operation, flexibility, throughput, reliability and otherwise for the performance of the devices when in use

The present invention relates to improved methods to detect and/or investigate the interaction between an analyte ligand and a cell or cell-like particle. Such methods use, in a particular way, a particular mass-sensitive chemical sensor comprising a surface acoustic wave device, to detect a particular property of an acoustic wave stimulated on the surface of such detector. The methods of the present invention are flexible and easy to perform, and can be used for example, to detect and investigate antibody interaction to extra-cellular domains of membrane proteins presented on intact mammalian cells.

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