Identification of a putative alphavirus receptor on mouse neural cells.

Alphaviruses replicate in a wide variety of cells in vitro. The prototype alphavirus, Sindbis virus, causes an age-dependent encephalitis in mice and serves as an important model system for the study of alphavirus neurovirulence. To begin to understand the role of cellular virus receptors in the pathogenesis of Sindbis virus infection, we developed an anti-idiotypic antibody made in rabbits against a neutralizing monoclonal antibody specific for the E2 surface glycoprotein. The anti-idiotypic antibody (anti-Id 209) bound to N18 mouse neuroblastoma cells and inhibited adsorption of 35S-labeled virus by 50%. Binding of anti-Id 209 was inhibited by pretreatment of N18 cells with various proteases but not with neuraminidase or phospholipase, while virus binding was inhibited by pretreatment with phospholipase as well as protease. Anti-Id 209 precipitated proteins of 110 and 74 kDa from N18 cells intrinsically labeled with [35S]methionine. N18 cells grow with two phenotypes in culture, and immunoprecipitation of 125I-surface-labeled cells showed that the 74-kDa protein was present on loosely adherent cells growing in aggregates, while the 110-kDa protein was present in smaller amounts on firmly adherent cells growing as a monolayer. Analysis of brain cells from newborn mice by flow cytometry showed that all cells expressed the receptor protein at birth, but by 4 days after birth half of the cells had ceased receptor expression. A survey of other cell lines showed the protein to be present on murine fibroblastic and other rodent neuroblastoma cell lines but rarely on human neural or nonneural cell lines. These studies suggest that one of the receptors for Sindbis virus on mouse neural cells is a protein that is regulated during development of the nervous system. Developmental down-regulation of receptor protein expression may contribute to the age-dependent nature of susceptibility of mice to fatal alphavirus encephalitis.     

Characterisation of the first enzymes committed to lysine biosynthesis in Arabidopsis thaliana

In plants, the lysine biosynthetic pathway is an attractive target for both the development of herbicides and increasing the nutritional value of crops given that lysine is a limiting amino acid in cereals. Dihydrodipicolinate synthase (DHDPS) and dihydrodipicolinate reductase (DHDPR) catalyse the first two committed steps of lysine biosynthesis. Here, we carry out for the first time a comprehensive characterisation of the structure and activity of both DHDPS and DHDPR from Arabidopsis thaliana. The A. thaliana DHDPS enzyme (At-DHDPS2) has similar activity to the bacterial form of the enzyme, but is more strongly allosterically inhibited by (S)-lysine. Structural studies of At-DHDPS2 show (S)-lysine bound at a cleft between two monomers, highlighting the allosteric site; however, unlike previous studies, binding is not accompanied by conformational changes, suggesting that binding may cause changes in protein dynamics rather than large conformation changes. DHDPR from A. thaliana (At-DHDPR2) has similar specificity for both NADH and NADPH during catalysis, and has tighter binding of substrate than has previously been reported. While all known bacterial DHDPR enzymes have a tetrameric structure, analytical ultracentrifugation, and scattering data unequivocally show that At-DHDPR2 exists as a dimer in solution. The exact arrangement of the dimeric protein is as yet unknown, but ab initio modelling of x-ray scattering data is consistent with an elongated structure in solution, which does not correspond to any of the possible dimeric pairings observed in the X-ray crystal structure of DHDPR from other organisms. This increased knowledge of the structure and function of plant lysine biosynthetic enzymes will aid future work aimed at improving primary production.     

MetaboLights: towards a new COSMOS of metabolomics data management

Exciting funding initiatives are emerging in Europe and the US for metabolomics data production, storage, dissemination and analysis. This is based on a rich ecosystem of resources around the world, which has been build during the past ten years, including but not limited to resources such as MassBank in Japan and the Human Metabolome Database in Canada. Now, the European Bioinformatics Institute has launched MetaboLights, a database for metabolomics experiments and the associated metadata (http://www.ebi.ac.uk/metabolights). It is the first comprehensive, cross-species, cross-platform metabolomics database maintained by one of the major open access data providers in molecular biology. In October, the European COSMOS consortium will start its work on Metabolomics data standardization, publication and dissemination workflows. The NIH in the US is establishing 6?C8 metabolomics services cores as well as a national metabolomics repository. This communication reports about MetaboLights as a new resource for Metabolomics research, summarises the related developments and outlines how they may consolidate the knowledge management in this third large omics field next to proteomics and genomics.     

Substrate Locking Promotes Dimer-Dimer Docking of an Enzyme Antibiotic Target

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Use of GPS tags to describe the home ranges,migration routes,stop-over locations and breeding area of Taiga Bean Geese Anser fabalis fabalis wintering in central Scotland

Capsule: Taiga Bean Geese Anser fabalis fabalis wintering near Falkirk, Scotland staged in Denmark, Norway and Sweden and summered in central Sweden.

Aims: To determine the migration routes, timing of movements, breeding area and home ranges of Taiga Bean Geese wintering near Falkirk, Scotland.

Methods: Ten Taiga Bean Geese, caught on the wintering grounds in Scotland, were marked with neck collars carrying global positioning system (GPS) tags. A further 21 geese were fitted with individually marked plastic neck collars. GPS location data were collected and field counts and searches for individually marked geese were undertaken to provide detailed information on their location throughout the year.

Results: Seven GPS tags provided information away from Scotland, indicating that two migration routes were used en route to the breeding grounds in Dalarna, Sweden. During the non-breeding season, the total home range of the geese was approximately 466?km², although the total area within agricultural fields used by the geese may have been as small as 13?km².

Conclusions: The timing of movements, migration routes, breeding area and identification of important stop-over sites for this wintering population are described for the first time.     

Cellular acidosis in rodents exposed to cadmium is caused by adaptation of the tissue rather than an early effect of toxicity

Proton (¹H) Nuclear Magnetic Resonance (NMR) spectroscopy was used to investigate the biochemical response of bank voles and wood mice (two wild rodent species frequently found on metal-contaminated sites) to chronic cadmium (Cd) insult. Similar effects, in terms of both metabolic changes (consistent with cellular acidosis) and induced metallothionin (MT) production were observed in all animals. These changes appeared to be an adaptation of the liver to toxic insult rather than onset of a toxic effect, and, in common with previous studies, were more marked in bank voles than wood mice. This may have reflected the greater Cd intake and assimilation of the former but was not explained by differences in concentrations of free (non MT-bound) Cd; concentrations of which were negligible in both voles and mice. Responses to Cd insult were detected in both species even though their bodies contained cadmium concentrations well below the World Health Organisation critical renal concentration of 200 μg/g dry mass.