Publications by authors named "Gunther Scheel"

3 Publications

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Two low complexity ultra-high throughput methods to identify diverse chemically bioactive molecules using Saccharomyces cerevisiae.

Microbiol Res 2017 Jun 21;199:10-18. Epub 2017 Feb 21.

Novartis Institutes for Biomedical Research, Novartis AG, Basel, Switzerland. Electronic address:

The budding yeast S. cerevisiae is widely used as a eukaryotic model organism to elucidate the mechanism of action of low molecular weight compounds. This report describes the development of two high throughput screening methods based on cell viability either by monitoring the reduction of alamarBlue (resazurin) or by direct optical measurement of cell growth. Both methods can be miniaturized to allow screening of large numbers of samples, and can be performed using S. cerevisiae in 384 and 1536-well format. The alamarBlue approach achieves Z' values of >0.7 with signal to basal ratios of >6.5, and around 1.1 million low molecular weight compounds were screened, identifying approximately 25,000 primary hits. Dose response curves generated for a subset (1930) using both alamarBlue and optical density methods showed significant overlap. In genome-wide haploinsufficiency profiling (HIP), 572 of these hits demonstrated a diverse mechanism of action, affecting >25% of all yeast strains.
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http://dx.doi.org/10.1016/j.micres.2017.02.004DOI Listing
June 2017

Hypothesis-driven screening.

Methods Mol Biol 2009 ;575:297-316

Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland.

Phenotypic chemogenomics studies require screening strategies that account for the complex nature of the experimental system. Unknown mechanism of action and high frequency of false positives and false negatives necessitate iterative experiments based on hypotheses formed on the basis of results from the previous step. Process-driven High Throughput Screening (HTS), aiming to "industrialize" lead finding and developed to maximize throughput, is rarely affording sufficient flexibility to design hypothesis-based experiments.In this contribution, we describe a High Throughput Cherry Picking (HTCP) system based on acoustic dispensing technology that was developed to support a new screening paradigm. We demonstrate the power of hypothesis-based screening in three chemogenomics studies that were recently conducted.
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http://dx.doi.org/10.1007/978-1-60761-274-2_13DOI Listing
February 2010

A multiparameter screening assay to assess the cytokine-induced expression of endothelial cell adhesion molecules.

Anal Biochem 2002 May;304(2):166-73

Novartis Pharma AG, CH-4002 Basel, Switzerland.

Compounds which inhibit endothelial cell inflammatory responses are believed to be of therapeutic value. The cell adhesion molecules E-selectin, ICAM-1, and VCAM-1 play important roles in inflammatory reactions by mediating leukocyte-endothelial interactions. To identify compounds which inhibit the expression of these adhesion molecules following cytokine stimulation we developed an assay which measures E-selectin, ICAM-1, and VCAM-1 in the same experiment. For this, we have taken advantage of the technology of time-resolved fluorimetry, which allows detection of several parameters in parallel, employing anti-E-selectin antibody labeled with europium, and anti-ICAM-1 and anti-VCAM-1 labeled with samarium and terbium, respectively. These antibodies were used to detect the respective antigens in human endothelial cells stimulated with TNFalpha or IL-1beta. In cross-competition assays these antibodies were found to bind specifically to TNF- or IL-1-stimulated cells. This assay, in which three parameters are measured in the same experiment, proved to be robust with signal to noise ratios of 25-35 for E-Selectin, 4-8 for ICAM-1, and 3-9 for VCAM-1. The assay proved to be reproducible in high-throughput screening. The experience with this assay demonstrates that multiple parameters can be measured in an enzyme-linked immunosorbent assay-type assay on cells by using time-resolved fluorimetry. The possibility of obtaining several parameters from one experiment is feasible under high-throughput screening conditions and is of interest for other experimental setups in which the simultaneous measurement of several parameters is desired.
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http://dx.doi.org/10.1006/abio.2002.5626DOI Listing
May 2002