Revealing pancrustacean relationships: Phylogenetic analysis of ribosomal protein genes places Collembola (springtails) in a monophyletic Hexapoda and reinforces the discrepancy between mitochondrial and nuclear DNA markers

Background  

In recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of DNA sequences. One of the challenged hypotheses is the monophyly of hexapods. This discussion originated from analyses based on mitochondrial DNA datasets that, due to an unusual positioning of Collembola, suggested that the hexapod body plan evolved at least twice. Here, we re-evaluate the position of Collembola using ribosomal protein gene sequences.     

A Versatile Synthesis of Enantiomerically Pure D- and L-Pyranosyl Nucleoside Analogues

Abstract

2-[[O-(p-Methoxybenzyl)-oxy]methyl]-5,6-dihydro-1,4-dithiin 1 is a versatile three carbon homologation reagent which has been conveniently used in the synthesis of enantiomerically pure modified nucleosides.     

Se-(2-aminoalkyl)selenocysteines as biochemical redox agents. A tool to contrast cell injury induced by aflatoxin B1 in HepG2 cells

Se-(2-aminoalkyl)selenocysteines were shown to have a chemoprotective activity towards HepG2 cells, contrasting the cell damage of aflatoxin B₁. The results of this study suggest that our newly synthesized seleno-diamino acids are apparently endowed with a potent protective potential against cell damage caused by AFB₁ similar to, or even higher than, that exerted by the reference compound Se-Me-SeCys. The protective effect does not seem to be absolute, i.e., merely determined by the presence of the chalcogen atom, but rather strictly related to the molecular structure of the new compounds tested. From this point of view, Se-(2-aminoalkyl)selenocysteines may represent a new class of biochemical redox agents fruitfully exploitable to contrast aflatoxin toxicity, at the same time a sound medical application and an economically relevant agricultural issue.     

Ranking non-synonymous single nucleotide polymorphisms based on disease concepts

As the number of non-synonymous single nucleotide polymorphisms (nsSNPs) identified through whole-exome/whole-genome sequencing programs increases, researchers and clinicians are becoming increasingly reliant upon computational prediction algorithms designed to prioritize potential functional variants for further study. A large proportion of existing prediction algorithms are ‘disease agnostic’ but are nevertheless quite capable of predicting when a mutation is likely to be deleterious. However, most clinical and research applications of these algorithms relate to specific diseases and would therefore benefit from an approach that discriminates between functional variants specifically related to that disease from those which are not. In a whole-exome/whole-genome sequencing context, such an approach could substantially reduce the number of false positive candidate mutations. Here, we test this postulate by incorporating a disease-specific weighting scheme into the Functional Analysis through Hidden Markov Models (FATHMM) algorithm. When compared to traditional prediction algorithms, we observed an overall reduction in the number of false positives identified using a disease-specific approach to functional prediction across 17 distinct disease concepts/categories. Our results illustrate the potential benefits of making disease-specific predictions when prioritizing candidate variants in relation to specific diseases. A web-based implementation of our algorithm is available at http://fathmm.biocompute.org.uk.     

Asymmetric Synthesis of Optically Active 1,3-Oxathiolane Nucleoside Analogues

Abstract

A ready asymmetric synthesis of 3′-oxa-4′-thionucleosides has been accomplished in three main steps from benzoyloxyethanal. The synthesis is characterized by high overall yield and appreciable enantiomeric excesses. It represents a general synthetic scheme to prepare a wide range of heterosubstituted sulfur-containing nucleoside analogues.