Latest App Notes & Case Studies

Two cell-based signaling assays from Invitrogen, Fluo-4 Direct™ Calcium Assay and Tango™-bla U2OS GPCR Assay, were performed on the PHERAstar FS HTS instrument. The PHERAstar FS has several unique features that enhance the performance of these assays including direct optic bottom reading, high resolution cell layer scanning, injection at the point of measurement and dual emission detection.

Bacteria can monitor and respond to changes to environmental conditions via a cell density process known as quorum sensing. Bacteria use this process to monitor their community by producing, detecting and responding to low molecular mass signal molecules, called autoinducers. Effects on quorum sensing were investigated by measuring growth and bioluminescence of Vibrio fischeri. The FLUOstar OPTIMA was utilized to measure absorbance and luminescence in parallel.

Functional screening of single cell clones was achieved using the HTRF® IP-One assay. The HTRF® assay from Cisbio proved to be a fast and reliable method to directly screen a large number of stable transfected single cell clones. Carbachol dose response curves with fresh cells from a growing culture and frozen instant cells showed similar results for EC50 and signal-to-blank values.

The alamarBlue® cell proliferation assay is based on a reducing environment that indicates metabolic active cells. Active cells are able to convert resazurin into the resorufin. Resazurin is blue and non-fluorescent whereas resorufin is red and highly fluorescent; therefore a fluorescent and a colorimetric detection are possible. This application notes focuses on the quantification of cell proliferation in a Human Osteoblast cell culture by measuring alamarBlue® fluorescence on the FLUOstar OPTIMA microplate reader.

A europium based time-resolved fluorescence cytotoxicity assay was used to study the loss of membrane integrity of target cells. For that cells are loaded with a fluorescence enhancing ligand that penetrates the cell membrane quickly and is hydrolized to form a hydrophilic ligand that is released from cells only after cytolysis. The data obtained with BMG LABTECH´s PHERAstar shows that estrogen dramatically reduces cell induced by natural killer cells.

High Throughput Screening (HTS) labs are required to screen ever-increasing numbers of compounds against an increasing number and variety of assay types. With a level of flexibility and adaptability unsurpassed in the world of automated systems, HighRes’ MicroStar™ is ideal. It meets not only today’s lab requirements; it also anticipates the easy exchange of today’s components with tomorrow’s technology.

Gene regulatory networks were used to identify novel regulatory hubs genes involved in the inflammatory response in human umbilical endothelial cells (HUVECs). To assess the potential role of these genes a leukocyte adhesion assay was utilized to screen for potential inflammatory markers. The FLUOstar OPTIMA microplate reader from BMG LABTECH was used for cell based bottom optic measurements and well scanning. The results show good reproducibility and can be adapted to e.g. primary neutrophils.

In a recent publication, Maurel et al* presented the combination of Cisbio’s HTRF and Covalys’ SNAP-and CLIP- Tag technologies to investigate cell-surface protein-protein interaction. In this study, an application for GPCR oligomerization was accurately documented and the advantages of this new approach presented.

A method for the quick and reliable analysis of size-selective paracellular tracer diffusion using fluorescent dextrans of different molecular weights is described. The assay could be easily adapted to large scale screens to identify genome-wide regulatory pathways or small molecules to modify junctional permeability. Using BMG LABTECH´s multimode plate reader FLUOstar OPTIMA for these experiments allows for quick and consistent fluorescence measurements in either kinetic or endpoint format.

NAD+, NADH as well as NADP+, NADPH have been known to play vital roles in energy metabolism, antioxidation, and reductive biosynthesis. Changes in these systems can be monitored using absorbance spectroscopy. NADH and NADPH absorb light at 340 nm, whereas NAD+ and NADP+ do not. The FLUOstar, POLARstar and SPECTROstar Omega microplate readers from BMG LABTECH all have a UV/Vis spectrometer that can measure any absorbance range from 220-850 nm.