Substrate specificity analysis of protein kinase complex Dbf2-Mob1 by peptide library and proteome array screening

Background  

The mitotic exit network (MEN) is a group of proteins that form a signaling cascade that is essential for cells to exit mitosis in Saccharomyces cerevisiae. The MEN has also been implicated in playing a role in cytokinesis. Two components of this signaling pathway are the protein kinase Dbf2 and its binding partner essential for its kinase activity, Mob1. The components of MEN that act upstream of Dbf2-Mob1 have been characterized, but physiological substrates for Dbf2-Mob1 have yet to be identified.     

Methodology for and the determination of the major constituents and metabolites of the Amazonian botanical medicine ayahuasca in human urine

Ayahuasca, also known as caapi or yage among various South American groups, holds a highly esteemed and millennia-old position in these cultures' medical and religious pharmacopeia. There is now an increasing interest in the potential for modern medical applications of ayahuasca, as well as concerns regarding its increasing potential for abuse. Toxicological and clinical research to address these issues will require information regarding its metabolism and clearance. Thus, a rapid, sensitive and specific method for characterization and quantitation of the major constituents and of the metabolites of ayahuasca in urine is needed. The present research provides a protocol for conducting such analyses. The characteristics of the method, conducted by sample dilution and using HPLC-electrospray ionization (ESI)-selected reaction monitoring (SRM)-tandem mass spectrometry, are presented. The application of the analytical protocol to urine samples collected from three individuals that were administered ayahuasca has also been demonstrated. The data show that the major metabolite of the hallucinogenic component of ayahuasca, N,N-dimethyltryptamine (DMT), is the corresponding N-oxide, the first time this metabolite has been described in in vivo studies in humans. Further, very little DMT was detected in urine, despite the inhibition of monoamine oxidase afforded by the presence of the harmala alkaloids in ayahuasca. The major harmala alkaloid excreted was tetrahydroharmine. Other excretion products and metabolites were also identified and quantified. The method described would be suitable for use in further toxicological and clinical research on ayahuasca.     

Direct analysis of psychoactive tryptamine and harmala alkaloids in the Amazonian botanical medicine ayahuasca by liquid chromatography–electrospray ionization-tandem mass spectrometry

A direct injection/liquid chromatography–electrospray ionization-tandem mass spectrometry procedure has been developed for the simultaneous quantitation of 11 compounds potentially found in the increasingly popular Amazonian botanical medicine and religious sacrament ayahuasca. The method utilizes a deuterated internal standard for quantitation and affords rapid detection of the alkaloids by a simple dilution assay, requiring no extraction procedures. Further, the method demonstrates a high degree of specificity for the compounds in question, as well as low limits of detection and quantitation despite using samples for analysis that had been diluted up to 200:1. This approach also appears to eliminate potential matrix effects. Method bias for each compound, examined over a range of concentrations, was also determined as was inter- and intra-assay variation. Its application to the analysis of three different ayahuasca preparations is also described. This method should prove useful in the study of ayahuasca in clinical and ethnobotanical research as well as in forensic examinations of ayahuasca preparations.     

Steady streaming around a spherical drop displaced from the velocity antinode in an acoustic levitation field

The steady (acoustic) streaming associated with a sphericaldrop displaced from the velocity antinode of a standing waveis studied. The ratio of the particle size to the acoustic wavelengthis treated as small but non-zero, and the solution is developedin the form of a two-term expansion in terms of the correspondingsmallness parameter. The drop viscosity is assumed to be muchhigher than that of the surrounding fluid, which is the casefor a drop in a gas medium. There are essentially three distinctregions where the steady streaming flow is analysed: insidethe drop (internal circulation), in the Stokes shear-wave layerat the surface on the gas side, and the gas outside the Stokeslayer (the outer streaming region). Solutions for the internalcirculation and the outer streaming are obtained in the limitof small Reynolds number. Despite the gas-to-liquid viscosity ratio being small, the outerstreaming may be dramatically affected by the fact that thesphere is liquid as opposed to solid. The parameter that measuresthe effect of liquidity is essentially the viscosity ratio dividedby the relative (to the particle size) thickness of the Stokeslayer. The case of a solid sphere is recovered by letting thisparameter go to zero.     

Ueber die Bestimmung des Cadmiums

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