Sondersammelgebiets-Volltexte
Refine
Year of publication
Document Type
- Article (8075)
- Part of Periodical (3330)
- Review (207)
- Book (191)
- Periodical (46)
- Report (43)
- Working Paper (34)
- Part of a Book (23)
- Conference Proceeding (19)
- Other (13)
Language
- German (5919)
- English (5654)
- French (175)
- Spanish (114)
- Multiple languages (100)
- cze (17)
- dut (13)
- Portuguese (10)
- Italian (1)
- Latin (1)
Is part of the Bibliography
- no (12005)
Keywords
- taxonomy (754)
- new species (452)
- morphology (167)
- distribution (127)
- biodiversity (114)
- Odonata (84)
- systematics (83)
- phylogeny (69)
- Pflanzengesellschaften (67)
- Taxonomy (61)
Institute
- Biowissenschaften (378)
- Extern (377)
- Institut für Ökologie, Evolution und Diversität (151)
- Senckenbergische Naturforschende Gesellschaft (139)
- Biochemie und Chemie (122)
- Medizin (114)
- Biodiversität und Klima Forschungszentrum (BiK-F) (104)
- Frankfurt Institute for Advanced Studies (FIAS) (45)
- Pharmazie (35)
- Exzellenzcluster Makromolekulare Komplexe (32)
Many interesting and important membrane proteins are hetero-oligomeric. However, besides naturally abundant examples, the structures of relatively few such complexes are known. Partly, this is due to difficulties in expression, stoichiometric assembly, and in the evaluation of their stability prior to crystallization trials. Here we describe a new approach, which allows rapid assessment of protein complex quality, assembly and stoichiometry, simplifying the search for conditions conducive to long-term stability and crystallization. Multicolour fluorescence size-exclusion chromatography (MC-FSEC) is used to enable tracking of individual subunits through expression, solubilization and purification steps. We show how the method has been applied to the heterodimeric transporter associated with antigen processing (TAP) and demonstrate how it may be extended in order to analyse membrane multisubunit assemblies.
A new type of Na+-driven ATP synthase membrane rotor with a two-carboxylate ion-coupling motif
(2013)
Abstract: The anaerobic bacterium Fusobacterium nucleatum uses glutamate decarboxylation to generate a transmembrane gradient of Na+. Here, we demonstrate that this ion-motive force is directly coupled to ATP synthesis, via an F1Fo-ATP synthase with a novel Na+ recognition motif, shared by other human pathogens. Molecular modeling and free-energy simulations of the rotary element of the enzyme, the c-ring, indicate Na+ specificity in physiological settings. Consistently, activity measurements showed Na+ stimulation of the enzyme, either membrane-embedded or isolated, and ATP synthesis was sensitive to the Na+ ionophore monensin. Furthermore, Na+ has a protective effect against inhibitors targeting the ion-binding sites, both in the complete ATP synthase and the isolated c-ring. Definitive evidence of Na+ coupling is provided by two identical crystal structures of the c11 ring, solved by X-ray crystallography at 2.2 and 2.6 Å resolution, at pH 5.3 and 8.7, respectively. Na+ ions occupy all binding sites, each coordinated by four amino acids and a water molecule. Intriguingly, two carboxylates instead of one mediate ion binding. Simulations and experiments demonstrate that this motif implies that a proton is concurrently bound to all sites, although Na+ alone drives the rotary mechanism. The structure thus reveals a new mode of ion coupling in ATP synthases and provides a basis for drug-design efforts against this opportunistic pathogen.
Author Summary: Essential cellular processes such as biosynthesis, transport, and motility are sustained by the energy released in the hydrolysis of ATP, the universal energy carrier in living cells. Most ATP in the cell is produced by a membrane-bound enzyme, the ATP synthase, through a rotary mechanism that is coupled to the translocation of ions across the membrane. The majority of ATP synthases are energized by transmembrane electrochemical gradients of protons (proton-motive force), but a number of organisms, including some important human pathogens, use gradients of sodium ions instead (sodium-motive force). The ion specificity of ATP synthases is determined by a membrane-embedded sub-complex, the c-ring, which is the smallest known biological rotor. The functional mechanism of the rotor ring and its variations among different organisms are of wide interest, because of this enzyme's impact on metabolism and disease, and because of its potential for nanotechnology applications. Here, we characterize a previously unrecognized type of Na+-driven ATP synthase from the opportunistic human pathogen Fusobacterium nucleatum, which is implicated in periodontal diseases. We analyzed this ATP synthase and its rotor ring through a multi-disciplinary approach, combining cell-growth and biochemical assays, X-ray crystallography and computer-simulation methods. Two crystal structures of the membrane rotor were solved, at low and high pH, revealing an atypical ion-recognition motif mediated by two carboxylate side-chains. This motif is shared by other human pathogens, such as Mycobacterium tuberculosis or Streptococcus pneumonia, whose ATP synthases are targets of novel antibiotic drugs. The implications of this ion-recognition mode on the mechanism of the ATP synthase and the cellular bioenergetics of F. nucleatum were thus examined. Our results provide the basis for future pharmacological efforts against this important pathogen.
Coleoptera species composition and succession in downed woody debris habitats are poorly known in eastern North America. A photoeclector emergence chamber was used to concentrate Coleoptera that emerged from various decay classes of fine and coarse woody debris (FWD and CWD, respectively) collected in primary and secondary forest sites in Great Smoky Mountains National Park, Tennessee, USA. A total of 5673 adult beetle specimens, representing 305 lowest identifiable taxa within 227 genera and 51 families, was collected. One hundred fifteen species (38%) were represented by single individuals. Many more specimens and species were collected from CWD (4129 and 247, respectively) than from FWD (1544 and 162, respectively), but species richness accumulation curves were not significantly different. Many more specimens but an equal number of species were collected from primary forest (3347 and 207, respectively) than from secondary forest (2326 and 207, respectively). Species accumulation curves indicated higher richness in secondary forests. Based on a subset of 71 species represented by 10 or more specimens, 27 species were associated with fresh fine woody debris, 11 species with weathered fine woody debris, four with coarse woody debris decay class I, 14 with coarse woody debris decay class II, and eight with coarse woody debris decay class III–IV. Sixteen species were associated with secondary forests, whereas 28 species were associated with primary forests. Coarse woody debris decay class II taken in primary forests had highest absolute species richness with 156 species. In coarse woody debris species overlap decreased with increased difference in decay indicating faunal succession. Published works related to the study of the ecology of downed woody material are briefly summarized. Recommendations on developing a database of legacy trees for future researchers are given. Notes on the biology and photographs of the 71 species represented by 10 or more specimens are given to provide an atlas of eastern U.S. beetle species most commonly encountered in these habitats.
The community within extremely decayed downed coarse woody debris, here referred to as decay class V (CWD5), has never been systematically sampled. The presumption has been that rotten wood is eventually overrun by surrounding soil and litter inhabitants. Leaf litter and CWD5 were sampled for Coleoptera with a sifting/ Berlese technique at three primary and three secondary forest sites in Great Smoky Mountains National Park, Tennessee, USA, during fall 2006 and spring 2007. A total of 4261 adult beetle specimens, representing 216 lowest identifiable taxa within 159 genera and 28 families, were collected. Sixty-six species (31%) were represented by single individuals. Many more specimens (3471) and species (170) were collected from leaf litter than from CWD5 (790 and 111, respectively) but species accumulation curves showed that species richness was not significantly different between the two habitats. Eight species were significantly associated with CWD5, and 40 species were significantly associated with leaf litter. Species richness was significantly higher in secondary forest than primary forest, but more species were significantly associated with primary than secondary forest. Species richness was significantly higher in spring than fall. Notes on the biology and photographs of the 59 species represented by 10 or more specimens are given to provide an atlas of common eastern U.S. beetle species found in these habitats. Overall CWD5 is a distinct but overlooked habitat that may harbor numerous undescribed species or species considered rare.
The insect fauna within inflorescences of Heliconia bourgaeana Petersen (Zingiberales: Heliconiaceae) was evaluated in Parque Metlac, Fortín de las Flores, Veracruz, Mexico between May and October 1995. Floral bracts were present in May and some persisted to October, despite much destruction in August by a grackle, Quiscalus mexicanus (JF Gmelin) (Icteridae). Flowers were abundant in the bracts in May-June, after which their number declined as fruits matured. Insects that fed on the flowers were most abundant in May-June; several of them could be pollinators; the immature stages of most of these insects were absent from Heliconia Linnaeus. The floral bracts contained water enriched by decomposition of the flowers, and this provided nutrition for aquatic organisms. Syrphid larvae (Diptera) contributed the largest biomass among the aquatic insects, and their distribution among bracts was more uniform in time than that of other aquatic insects. Larvae of Culicidae and Psychodidae (Diptera) were more variable in density and were more abundant after decomposition of the flowers. The most abundant aquatic predators of culicid larvae were larvae of Toxorhynchites Theobald (Culicidae). The most abundant amphibious predators of dipterous larvae were adults of four species of Platydracus Thomson (Staphylinidae), one of them yet undescribed. To capture its prey, the Platydracus adult would immerse its head and thorax, with open mandibles, to snap at passing dipterous larvae.
A re-description and new records of Onthophagus viriditinctus Reitter, 1892 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini), an uncommon species from Iran, are provided. The taxonomic position and some nomenclatural problems are discussed. The placement in the subgenus Exonthophagus Kabakov, 2006 is proposed. Images of the male, female, aedeagus and drawings of lamella copulatrix of Onthophagus viriditinctus and Onthophagus haroldi Ballion, 1871, the only other species included in the subgenus, are supplied. A key for distinguishing the two species is provided.
Two new species of Goera, G. zwicki and G. nozakii (Trichoptera, Goeridae), from the Philippines and one new species, G. meyi, from Vietnam are described and illustrated herein. In addition, type specimens of G. disparilis Banks, G. octospina Banks, G. tagalica Banks, and G. uniformis Banks are illustrated. All species of Goera known from both the Philippines and Vietnam are listed.
Se describen e ilustran las hembras adultas de dos especies nuevas de Acanthococcus Signoret (Hemiptera: Coccoidea: Eriococcidae), Acanthococcus julietae González y Granara de Willink sp. nov. y A. saltensis González y Granara de Willink sp. nov. y los estados ninfales de la última. Se presenta una clave para separar las especies de Eriococcidae reportados sobre Asteraceae de la Argentina.
Surveys for adult Cylindera (s. str.) lunalonga (Schaupp) (Coleoptera: Carabidae: Cicindelinae) were conducted between 2001 and 2011 at over 80 sites throughout the species’ historic range in the San Joaquin Valley and Sierra Nevada Mountains of California. Previously considered extirpated from the Valley, these surveys resulted in finding adults at 18 sites, several with large populations (>50 individuals). As suggested by historic records, our studies confirmed that the Valley populations of Cy. lunalonga occur in what were historically wetland sites, but are now lowland agricultural croplands. Adults were always associated with wet, muddy soil within and along the edges of irrigation ditches. A comparison of morphology, behavior, habitat, and conservation is made with the only known extant Sierra Nevada population.
Stakeholder dialogues can be used not only to introduce and discuss the various demands of the participants. Under certain circumstances they can also serve to smoothen out and solve conflicts that arise in connection with the use and conservation of biodiversity. In order to be successful in this respect, it is crucial to create a situation enabling a process of joint learning. A positive effect might also be achieved by the formation of groups that evolve in the course of a succession of workshops as well as speeches and special items on the agenda. In order for the workshops to be successful, they should be supported by frequent stakeholder analyses. In this guideline we are listing related principles and indications from the literature as well as our own experiences geared towards jointly solving biodiversity conflicts and creating islands of consensus.