Analytical separation of plasmid DNA isoforms using anion exchanging chromatographic monoliths with 6 µm channels.

High-performance liquid chromatography (HPLC)-based analytical assays are used to effectively monitor purity and quantity of plasmid DNA (pDNA) throughout the purification process. However, the phenomenon of physical entrapment of open circular (OC) isoforms pDNA inside narrow channels of chromatographic support decreases its accuracy and precision and the effect increases with pDNA size. The purpose of the study was to develop a chromatographic method for accurate analytical separation between isoforms of <16 kbp pDNA using weak anion exchanging monolithic column with large (6 µm) convective channels.

Optimization of SELEX: comparison of different methods for monitoring the progress of in vitro selection of aptamers.

Oligonucleotide aptamers are selected from libraries typically comprising up to 10(15) different sequences by an iterative process of binding, separation, amplification and purification, called SELEX. During this process, the diversity of the oligonucleotide pool decreases until, presumably, only sequences with highest binding affinities towards chosen targets remain. This selection technique is time-consuming, labor-intensive and expensive.

Quantitative cell wall protein profiling of invasive and non-invasive Saccharomyces cerevisiae strains.

A new, simple approach for the isolation and quantitative analysis of the cell wall (CW) proteins from invasively growing Saccharomyces cerevisiae strains is described in this contribution. The proposed method was proved compatible with agar-invasion assays and was demonstrated to be useful as a screening tool for rapid analysis of CW protein determinants related to yeast adhesion and invasion processes. CW protein isolation was performed enzymatically on viable cells by using mild, isosmotic reaction conditions and pure, proteinase free glucanase, thus avoiding destruction of cells and protein structures, which is a drawback of the existing methods based on hot SDS, DTT or NaOH treatment.

Application of chromogenic reagents in surface plasmon resonance (SPR).

In this paper, a new simple approach for sensitivity optimization in surface plasmon resonance (SPR) chemosensors based on colorimetric ligands is presented. A new design of SPR sensor with tunable analytical wavelength (lambda(SPR)) was constructed for this purpose, to perform studies on the ligand absorbance spectra related sensitivity enhancement. Unlike commercial SPR sensors which operate at one lambda(SPR), the new device can be used for sensitivity analysis at selected lambda(SPR) in the range 550-750 nm, offering the possibility to identify the highest sensitivity lambda(SPR) in regard to the spectral changes of the selected ligand.