Chemical Identity and Mechanism of Action and Formation of a Cell Growth Inhibitory Compound from Polycarbonate Flasks.

This paper reports the chemical identity and mechanism of action and formation of a cell growth inhibitory compound leached from some single-use Erlenmeyer polycarbonate shaker flasks under routine cell culture conditions. Single-use cell culture vessels have been increasingly used for the production of biopharmaceuticals; however, they often suffer from issues associated with leachables that may interfere with cell growth and protein stability. Here, high-performance liquid-chromatography preparations and cell proliferation assays led to identification of a compound from the water extracts of some polycarbonate flasks, which exhibited subline- and seeding density-dependent growth inhibition of CHO cells in suspension culture.

Air-stable G protein-coupled receptor microarrays and ligand binding characteristics.

This paper described novel strategies to achieve air-stable G protein-coupled receptor (GPCR) microarrays and the uses of the microarrays for ligand profiling. Specifically, GPCR cell membrane fragments were suspended in a buffered solution containing bovine serum albumin (BSA) and disaccharide sucrose or trehalose and used for fabricating GPCR microarrays. During the array fabrication and postfabrication processes, BSA molecules were found to effectively form packed layer(s) surrounding the GPCR membranes immobilized onto the predetermined printing area, thereby stabilizing the membrane microspots.

Identification of hemes and related cyclic tetrapyrroles by matrix-assisted laser desorption/ionization and liquid secondary ion mass spectrometry.

Mass spectrometry has proven to be a powerful technique applicable on trace amounts for the identification of known hemes and cyclic tetrapyrroles, and for providing critical information for the structure of new and novel versions. This report describes investigations of the practical limits of detection for such bioinorganic prosthetic groups, primarily by liquid secondary ion mass spectrometry (LSIMS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), including a survey of the utility of common matrices. The lower limit of detection under favorable conditions extends to low picomole amounts.