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Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Ribosomal RNA-targeted nucleic acid probes for studies in microbial ecology

FEMS MICROBIOLOGY REVIEWS, Issue 5 2000
Rudolf Amann
Abstract With readily applicable hybridization assays, mainly based on rRNA-targeted nucleic acid probes, and direct, cultivation-independent sequence retrieval, microbiologists can for the first time determine the true composition of microbial communities. Phylogenetic identification and exact spatiotemporal quantification of microorganisms will in the future become prerequisites for high quality studies in microbial ecology just as good taxonomy and solid quantification have always been for macroecology. This review is intended to give a short history of the development of rRNA-targeted nucleic acid probes and probe technologies, as well as of their application in microbial ecology. The current state of the art is described, and we will try to look into the future. Over the last decade, rRNA-targeted probes have become a handy tool for microbial ecologists. In order to speed up the transformation of microbial ecology from a mostly descriptive to a hypothesis-driven, experimental science more intense use must be made of the taxonomic precision and quantitativeness of rRNA-targeted probes. [source]

Digitization and geo-referencing of botanical distribution maps

JOURNAL OF BIOGEOGRAPHY, Issue 7 2002
Christian A. Schölzel
Aim In many fields of research, valuable information is stored in atlases and maps which are only available as printed media. Scientists who are interested in computational analysis often seek to digitize the data to make it accessible for numerical calculations. In this paper, an approach using the example of digitizing distribution maps taken from plant-taxonomic atlases is described. For this purpose, a software tool has been built for application in the Sonderforschungsbereich 350 `Interactions between and Modelling of Continental Geosystems' at the University of Bonn. Its functionality has to be simple in use and capable of transforming fields drawn on geographical maps into grid data even where the type of map projection is unknown. Location As an example, plant distributions over Europe and Asia have been digitized. Methods To achieve this aim through an objective statistical analysis, the local deterministic approximation has been used for geo-referencing. Results For this reason the development of a new software tool was required. Although there is a large market for related software from Geographical Information Systems (GIS), none of the available GIS-programs appeared to be capable of geo-referencing maps with unidentified projections. Rather than to give a product comparison, this paper aims on the methodology and mathematical formalism. Main conclusions The developed algorithm is a handy tool to capture data from maps based on obscure projections. Valuable historical maps, which are problematic for standard GIS-programs, can be made accessible for modern research work. [source]

Measurement of xenobiotics in saliva: is saliva an attractive alternative matrix?

BIOMEDICAL CHROMATOGRAPHY, Issue 1 2009
Case studies, analytical perspectives
Abstract The use of saliva for measuring xenobiotic concentrations has been practiced for a number of years. While the use of saliva has been generally reserved for the analysis of diagnostic and forensic/toxicology samples, attempts have been made to further enhance the value of saliva as an alternate matrix to those of plasma and serum. It is understood that saliva represents a handy tool for therapeutic drug monitoring (TDM) as it offers certain distinctive advantages. This scope of this review encompasses the following: (a) a comprehensive view of saliva as an alternate matrix for either plasma or serum to understand the pharmacokinetic/pharmacodynamic (PK/PD) characteristics; (b) an account of the factors contributing to the observed variability in salivary monitoring; (c) a tabular compilation of diverse case studies of xenobitoics belonging to different therapeutic classes with emphasis on assay methodology and applicable analytical/biopharmaceutical/pharmacokinetic findings; (d) relevant thoughts on assay procedures as they relate to salivary monitoring; and (e) some representative case studies highlighting the new thinking on the use of saliva outside of traditional TDM. Overall, based on the review, saliva represents a valuable TDM tool for a number of xenobiotics. While parent compound and phase I metabolite(s) for many xenobiotics have been generally quantifiable in saliva, phase II metabolites have not generally been detected in saliva. Therefore saliva samples could also be used to answer some specific PK/PD questions during the drug development process, if applicable. However, the development and validation of the assay in saliva needs to be carried out carefully with particular focus on proper sample collection, processing and storage to ensure the stability of the xenobiotics and with the same rigor as applied to plasma, serum and urine matrices. Copyright © 2008 John Wiley & Sons, Ltd. [source]

NMR Spectroscopy of Paramagnetic Metalloproteins

CHEMBIOCHEM, Issue 9 2005
Ivano Bertini Prof.
Abstract This article deals with the solution structure determination of paramagnetic metalloproteins by NMR spectroscopy. These proteins were believed not to be suitable for NMR investigations for structure determination until a decade ago, but eventually novel experiments and software protocols were developed, with the aim of making the approach suitable for the goal and as user-friendly and safe as possible. In the article, we also give hints for the optimization of experiments with respect to each particular metal ion, with the aim of also providing a handy tool for nonspecialists. Finally, a section is dedicated to the significant progress made on13C direct detection, which reduces the negative effects of paramagnetism and may constitute a new chapter in the whole field of NMR spectroscopy. [source]