Cancer-ID: Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood.

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1 µm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1 µm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic.

Dispersive kinetics in discotic liquid crystals.

The dynamics of the discotic liquid-crystalline system, hexakis (n-hexyloxy) triphenylene (HAT6), is considered in the frame of the phenomenological model for rate processes proposed by Berlin. It describes the evolution of the system in the presence of the long-time scale correlations in the system, and we compare this with experimental quasielastic neutron scattering of the molecular assembly of HAT6 in the columnar phase. We interpret the parameters of this model in terms of nonextensive thermodynamics in which rare events in the local fast dynamics of some parts of the system control the slower dynamics of the larger molecular entity and lead to a fractional diffusion equation. The importance of these rare local events to the overall dynamics of the system is linked to the entropic index, this being obtained from the data within the model approach. Analysis of the waiting-time dependence from momentum transfer reveals a Lévy distribution of jump lengths, which allows us to construct the van Hove correlation function for discotic liquid-crystalline system.

Separation of amino acid enantiomers by micelle-enhanced ultrafiltration.

A Micelle-enhanced ultrafiltration (MEUF) separation process was investigated that can potentially be used for large-scale enantioseparations. Copper(II)-amino acid derivatives dissolved in nonionic surfactant micelles were used as chiral selectors for the separation of dilute racemic amino acids solutions. For the alpha-amino acids phenylalanine, phenylglycine, O-methyltyrosine, isoleucine, and leucine good separation was obtained using cholesteryl L-glutamate and Cu(II) ions as chiral selector with an operational enantioselectivity (alpha(op)) up to 14.5 for phenylglycine. From a wide set of substrates, including four beta-amino acids, it was concluded that the performance of this system is determined by two factors: the hydrophobicity of the racemic amino acid, which results in a partitioning of the racemic amino acid over micelle and aqueous solution, and the stability of the diastereomeric complex formed upon binding of the amino acid with the chiral selector. The chiral hydrophobic cholesteryl anchor of the chiral selector also plays an active role in the recognition process, since inversion of the chirality of the glutamate does not yield the reciprocal enantioselectivities. However, if the cholesteryl group is replaced by a nonchiral alkyl chain, reciprocal operational enantioselectivities are found with enantiomeric glutamate selectors.

Enhanced (+)-catechin transglucosylating activity of Streptococcus mutans GS-5 glucosyltransferase-D due to fructose removal.

The (+)-catechin transglucosylating activities of several glucosyltransferases (GTFs) from the genus Streptococcus were compared. For this purpose, a mixture of four GTFs from Streptococcus sobrinus SL-1 and recombinant GTF-B and GTF-D from Streptococcus mutans GS-5 expressed in Escherichia coli were studied. It was shown that after removal of alpha-glucosidase activity, GTF-D transglucosylated catechin with the highest efficiency. A maximal yield (expressed as the ratio of moles of glucoside formed to moles of catechin initially added) of 90% was observed with 10 mM catechin and 100 mM sucrose (K(m), 13 mM) in 125 mM potassium phosphate, pH 6.0, at 37 degrees C. (1)H and (13)C nuclear magnetic resonance spectroscopy revealed the structures of two catechin glucosides, (+)-catechin-4'-O-alpha-D-glucopyranoside and (+)-catechin-4',7-O-alpha-di-D-glucopyranoside. Fructose accumulation during glucosyl transfer from sucrose to the acceptor competitively inhibited catechin transglucosylation (K(i), 9.3 mM), whereas glucose did not inhibit catechin transglucosylation. The addition of yeasts was studied in order to minimize fructose inhibition by means of fructose removal. For this purpose, the yeasts Pichia pastoris and the mutant Saccharomyces cerevisiae T2-3D were selected because of their inabilities to utilize sucrose. Addition of P. pastoris or S. cerevisiae T2-3D to the standard reaction mixture resulted in a twofold increase in the duration of the maximum GTF-D transglucosylation rate. The addition of the yeasts also stimulated sucrose utilization by GTF-D.