A major challenge in the research on membrane-anchored and integral membrane protein complexes is to obtain these in a functionally active, water-soluble, and monodisperse form. This requires the incorporation of the membrane proteins into a native-like membrane or detergent micelle that mimics the properties of the original biological membrane. However, solubilization in detergents or reconstitution in liposomes or supported monolayers sometimes suffers from loss of activity and problematic analyses due to heterogeneity and aggregation. A developing technology termed nanodiscs exploits discoidal phospholipid bilayers encircled by a stabilizing amphipatic helical membrane scaffold protein to reconstitute membranes with integral proteins. After reconstitution, the membrane nanodisc is soluble, stable, and monodisperse. In the present review, we outline the biological inspiration for nanodiscs as discoidal high-density lipoproteins, the assembly and handling of nanodiscs, and finally their diverse biochemical applications. In our view, major advantages of nanodisc technology for integral membrane proteins is homogeneity, control of oligomerization state, access to both sides of the membrane, and control of lipids in the local membrane environment of the integral protein.

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BackgroundThe systematic analysis of a large number of comparable plant trait data can support investigations into phylogenetics and ecological adaptation, with broad applications in evolutionary biology, agriculture, conservation, and the functioning of ecosystems. Floras, i.e., books collecting the information on all known plant species found within a region, are a potentially rich source of such plant trait data. Floras describe plant traits with a focus on morphology and other traits relevant for species identification in addition to other characteristics of plant species, such as ecological affinities, distribution, economic value, health applications, traditional uses, and so on. However, a key limitation in systematically analyzing information in Floras is the lack of a standardized vocabulary for the described traits as well as the difficulties in extracting structured information from free text.ResultsWe have developed the Flora Phenotype Ontology (FLOPO), an ontology for describing traits of plant species found in Floras. We used the Plant Ontology (PO) and the Phenotype And Trait Ontology (PATO) to extract entity-quality relationships from digitized taxon descriptions in Floras, and used a formal ontological approach based on phenotype description patterns and automated reasoning to generate the FLOPO. The resulting ontology consists of 25,407 classes and is based on the PO and PATO. The classified ontology closely follows the structure of Plant Ontology in that the primary axis of classification is the observed plant anatomical structure, and more specific traits are then classified based on parthood and subclass relations between anatomical structures as well as subclass relations between phenotypic qualities.ConclusionsThe FLOPO is primarily intended as a framework based on which plant traits can be integrated computationally across all species and higher taxa of flowering plants. Importantly, it is not intended to replace established vocabularies or ontologies, but rather serve as an overarching framework based on which different application- and domain-specific ontologies, thesauri and vocabularies of phenotypes observed in flowering plants can be integrated.Electronic supplementary materialThe online version of this article (doi:10.1186/s13326-016-0107-8) contains supplementary material, which is available to authorized users.

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On the basis of data in the literature, the percentages of dextral versus sinistral species of snails have been calculated for western Europe, Turkey, North America (north of Mexico), and Japan. When the family of Clausiliidae is represented, about a quarter of all snail species may be sinistral, whereas less than one per cent of the species may be sinistral where that family does not occur. The number of single-gene speciation events on the basis of chirality, resulting in the origin of mirror image species, is not closely linked to the percentage of sinistral versus dextral species in a particular region. Turkey is nevertheless exceptional by both a high percentage of sinistral species and a high number of speciation events resulting in mirror image species. Shell morphology and genetic background may influence the ease of chirality-linked speciation, whereas sinistrality may additionally be selected against by internal selection. For the Clausiliidae, the fossil record and the recent fauna suggest that successful reversals in coiling direction occurred with a frequency of once every three to four million years.