Micelles protect membrane complexes from solution to vacuum

The ability to maintain interactions between soluble protein subunits in the gas phase of a mass spectrometer gives critical insight into the stoichiometry and interaction networks of protein complexes. Conversely, for membrane protein complexes in micelles, the transition into the gas phase usually leads to the disruption of interactions, particularly between cytoplasmic and membrane subunits, and a mass spectrum dominated by large aggregates of detergent molecules. We show that by applying nanoelectrospray to a micellar solution of a membrane protein complex, the heteromeric adenosine 5'-triphosphate (ATP)-binding cassette transporter BtuC2D2, we can maintain the complex intact in the gas phase of a mass spectrometer. Dissociation of either transmembrane (BtuC) or cytoplasmic (BtuD) subunits uncovers modifications to the transmembrane subunits and cooperative binding of ATP. By protecting a membrane protein complex within a n-dodecyl-beta-d-maltoside micelle, we demonstrated a powerful strategy that will enable the subunit stoichiometry and ligand-binding properties of membrane complexes to be determined directly, by precise determination of the masses of intact complexes and dissociated subunits.     

Promoting the Middle East peace process by changing beliefs about group malleability

Four studies showed that beliefs about whether groups have a malleable versus fixed nature affected intergroup attitudes and willingness to compromise for peace. Using a nationwide sample (N = 500) of Israeli Jews, the first study showed that a belief that groups were malleable predicted positive attitudes toward Palestinians, which in turn predicted willingness to compromise. In the remaining three studies, experimentally inducing malleable versus fixed beliefs about groups among Israeli Jews (N = 76), Palestinian citizens of Israel (N = 59), and Palestinians in the West Bank (N = 53)--without mentioning the adversary--led to more positive attitudes toward the outgroup and, in turn, increased willingness to compromise for peace.     

Independent codes for spatial and episodic memory in hippocampal neuronal ensembles

Hippocampal neurons were recorded under conditions in which the recording chamber was varied but its location remained unchanged versus conditions in which an identical chamber was encountered in different places. Two forms of neuronal pattern separation occurred. In the variable cue-constant place condition, the firing rates of active cells varied, often over more than an order of magnitude, whereas the location of firing remained constant. In the variable place-constant cue condition, both location and rates changed, so that population vectors for a given location in the chamber were statistically independent. These independent encoding schemes may enable simultaneous representation of spatial and episodic memory information.     

Identification of parents suitable for molecular mapping of immunity and resistance genes in solanum species

A survey of DNA polymorphisms and bacterial ring rot reactions inSolanum species was conducted to identify parents that when crossed would produce an F₁ mapping population useful for identifying DNA markers tightly linked to genes for immunity or resistance to bacterial ring rot.Solanum tuberosum, S. acaule, diploidSolanum species, doubled monoploid lines ofS. phureja, and somatic fusion hybrids betweenS. tuberosum andS. brevidens were established in tissue culture from single true potato seeds or tubers and evaluated for bacterial ring rot reactions in greenhouse studies with root-inoculated tissue cultured plantlets. Establishment of tissue culture stocks insured the availability of homogeneous genetic material for use in bacterial ring rot assays and genetic analyses. Presence ofClavibacter michiganense subsp.sepedonicum was assessed in stems by an immunofluorescence antibody assay (IFAS). Two accessions were found to be immune to bacterial ring rot. DNA polymorphisms were detected within and among 24 accessions evaluated with 24 RFLP markers and 10 arbitrary oligonucleotide primers (RAPDs). These results identify parents suitable for future mapping of gene (s) for immunity or resistance to bacterial ring rot.     

Observations on the structure and osmotic potentials of parenchyma associated with the internal phloem of potato tubers

The structure and osmotic potentials of parenchyma cells associated with internal phloem of growing, dormant, and sprouting potato tubers (Solanum tuberosum L. cv. Irish Cobbler) were studied. Companion cells, specialized parenchyma cells, and storage parenchyma cells were recognizable by differences in structural characteristics. Companion cells were usually densely cytoplasmic with numerous large mitochondria and plastids with little or no starch. The specialized parenchyma cells which surrounded groups of sieve tubes and companion cells had numerous vacuoles of various size, small mitochondria, plastids with very little or no starch, and protein inclusions. Storage parenchyma cells had amyloplasts with very large starch grains, a large central vacuole with osmiophilic inclusions, and few organelles in a peripheral cytoplasm. The osmotic potentials of specialized parenchyma cells and storage parenchyma cells were similar and did not vary regardless of whether the tubers were growing, dormant, or sprouting.     

Genetic diversity of the pea root pathogen Aphanomyces euteiches in Europe

The oomycete pathogen Aphanomyces euteiches causes root rot in various legume species. In this study we focused on A. euteiches causing root rot in pea (Pisum sativum), thereby being responsible for severe yield losses in pea production. We aimed to understand the genetic diversity of A. euteiches in Europe, covering a north-to-south gradient spanning from Sweden, Norway and Finland to the UK, France and Italy. A collection of 85 European A. euteiches strains was obtained, all isolated from infected pea roots from commercial vining pea cultivation fields. The strains were genotyped using 22 simple-sequence repeat markers. Multilocus genotypes were compiled and the genetic diversity between individual strains and population structure between countries was analysed. The population comprising strains from Italy was genetically different and did not share ancestry with any other population. Also, strains originating from Finland and the eastern parts of Sweden were found to be significantly different from the other populations, while strains from the rest of Europe were more closely related. A subset of 10 A. euteiches strains from four countries was further phenotyped on two susceptible pea genotypes, as well as on one genotype with partial resistance towards A. euteiches. All strains were pathogenic on all pea genotypes, but with varying levels of disease severity. No correlation between the genetic relatedness of strains and virulence levels was found. In summary, our study identified three genetically distinct groups of A. euteiches in Europe along a north-to-south gradient, indicating local pathogen differentiation.     

Ethical dilemmas in veterinary medicine.

Veterinarians frequently encounter situations that are morally charged and potentially difficult to manage. Situation involving euthanasia, end-of-life care, economics, and inadequate provision of care create practical and moral dilemmas. Ethical tension may be attributable to differences in beliefs regarding the moral value of animals, client and veterinary responsibilities, and deciding what is best for an animal. Veterinarians can employ communication skills used in medical situations to explore the reasons underpinning ethical dilemmas and to search for solutions with clients, staff, and colleagues.     

Structures of SAS-6 suggest its organization in centrioles

Centrioles are cylindrical, ninefold symmetrical structures with peripheral triplet microtubules strictly required to template cilia and flagella. The highly conserved protein SAS-6 constitutes the center of the cartwheel assembly that scaffolds centrioles early in their biogenesis. We determined the x-ray structure of the amino-terminal domain of SAS-6 from zebrafish, and we show that recombinant SAS-6 self-associates in vitro into assemblies that resemble cartwheel centers. Point mutations are consistent with the notion that centriole formation in vivo depends on the interactions that define the self-assemblies observed here. Thus, these interactions are probably essential to the structural organization of cartwheel centers.     

From burgers to biodiversity? The McDonaldization of on-farm nature conservation in the UK

This paper uses George Ritzer’s account of McDonaldization – the socially transformative process of rationalization – to undertake a critical analysis of agri-environment schemes, the dominant form of on-farm nature conservation in England. Drawing on a wide range of evidence, including social surveys of the participants and non-participants of agri-environment schemes, government files, and interviews with government officials, the four key dimensions of McDonaldization – efficiency, calculability, predictability, and control (through non-human technologies) – are applied to the analysis of agri-environment schemes. The irrationalities emerging from a McDonaldized approach to nature conservation are discussed together with their implications for farmers, nature, and society. In conclusion, the paper points to the emergence of alternative models of on-farm nature conservation that may offer ways of resisting and displacing the McDonaldized version. Carol Morris is Professor of Geography at the University of Nottingham, Nottingham, UK. Her research is broadly concerned with the application of social scientific approaches to the critical analysis of issues and problems affecting the rural environment and agro-food system in British and European contexts. Matt Reed is Research Fellow in the ESRC Centre for the Study of Genomics in Society (EGENIS), University of Exeter, UK and a visiting Fellow in the Centre for Rural Research at the University of Exeter, UK. The main focus of his research has been the organic food and farming movement, but he also has conducted research on family farming, rural protest movements, and the local food economy.