449 research outputs found
Plattform Pflanzenschutzstrategien im Öko-Landbau
Im Rahmen des Projekts „Plattform Pflanzenschutzstrategien im Ökologischen Landbau“ wurden Strategien zur Gesunderhaltung der Kulturpflanzen im Ökolandbau weiterentwickelt, insbesondere die kurz zuvor etablierte Strategie zur Minimierung des Einsatzes von Kupfer als Pflanzenschutzmittel. Außerdem wurde an Konzepten für eine moderne, transparente Kommunikation zu Strategien und Maßnahmen zur Erhaltung der Pflanzengesundheit im Ökolandbau gearbeitet und mit der Plattform ein Instrument für einen effizienten, fachlich fundierten und verbandsübergreifenden Meinungsaustausch zu Pflanzenschutz-Fragestellungen und insbesondere zu Änderungen hinsichtlich von im Ökolandbau zulässigen Inputs etabliert.
Die Projektfragestellungen wurden mit Workshops der beteiligten Institutionen und Expertengutachten bearbeitet und die Ergebnisse über Veröffentlichungen in den relevanten Medien der Bio-Branche und über den direkten Input in die Beratungsnetzwerke der Öko-Verbände kommuniziert.
Im Projektverlauf konnten wesentliche Fortschritte bei der Aktualisierung der Kupferminimierungsstrategie erzielt werden, außerdem konnte die Plattform dazu beitragen, Herausforderungen zu identifizieren, die sich für die Praxis und für Hersteller von Ökolandbautauglichen Pflanzenbehandlungsmitteln aus der Novellierung des europäischen und nationalen Pflanzenschutzrechts und von Veränderungen in der EU-Öko-Verordnung ergaben. Auch die Zulassung von Naturstoffen für die Verwendung im Ökolandbau wurde fachlich unterstützt und begleitet
Preferential attachment in the protein network evolution
The Saccharomyces cerevisiae protein-protein interaction map, as well as many
natural and man-made networks, shares the scale-free topology. The preferential
attachment model was suggested as a generic network evolution model that yields
this universal topology. However, it is not clear that the model assumptions
hold for the protein interaction network. Using a cross genome comparison we
show that (a) the older a protein, the better connected it is, and (b) The
number of interactions a protein gains during its evolution is proportional to
its connectivity. Therefore, preferential attachment governs the protein
network evolution. The evolutionary mechanism leading to such preference and
some implications are discussed.Comment: Minor changes per referees requests; to appear in PR
Simulation of a quantum phase transition of polaritons with trapped ions
We present a novel system for the simulation of quantum phase transitions of
collective internal qubit and phononic states with a linear crystal of trapped
ions. The laser-ion interaction creates an energy gap in the excitation
spectrum, which induces an effective phonon-phonon repulsion and a
Jaynes-Cummings-Hubbard interaction. This system shows features equivalent to
phase transitions of polaritons in coupled cavity arrays. Trapped ions allow
for easy tunabilty of the hopping frequency by adjusting the axial trapping
frequency, and the phonon-phonon repulsion via the laser detuning and
intensity. We propose an experimental protocol to access all observables of the
system, which allows one to obtain signatures of the quantum phase transitions
even with a small number of ions.Comment: 4 pages, 3 figure
An Introductory Guide to Aligning Networks Using SANA, the Simulated Annealing Network Aligner.
Sequence alignment has had an enormous impact on our understanding of biology, evolution, and disease. The alignment of biological networks holds similar promise. Biological networks generally model interactions between biomolecules such as proteins, genes, metabolites, or mRNAs. There is strong evidence that the network topology-the "structure" of the network-is correlated with the functions performed, so that network topology can be used to help predict or understand function. However, unlike sequence comparison and alignment-which is an essentially solved problem-network comparison and alignment is an NP-complete problem for which heuristic algorithms must be used.Here we introduce SANA, the Simulated Annealing Network Aligner. SANA is one of many algorithms proposed for the arena of biological network alignment. In the context of global network alignment, SANA stands out for its speed, memory efficiency, ease-of-use, and flexibility in the arena of producing alignments between two or more networks. SANA produces better alignments in minutes on a laptop than most other algorithms can produce in hours or days of CPU time on large server-class machines. We walk the user through how to use SANA for several types of biomolecular networks
Revisiting Date and Party Hubs: Novel Approaches to Role Assignment in Protein Interaction Networks
The idea of 'date' and 'party' hubs has been influential in the study of
protein-protein interaction networks. Date hubs display low co-expression with
their partners, whilst party hubs have high co-expression. It was proposed that
party hubs are local coordinators whereas date hubs are global connectors. Here
we show that the reported importance of date hubs to network connectivity can
in fact be attributed to a tiny subset of them. Crucially, these few, extremely
central, hubs do not display particularly low expression correlation,
undermining the idea of a link between this quantity and hub function. The
date/party distinction was originally motivated by an approximately bimodal
distribution of hub co-expression; we show that this feature is not always
robust to methodological changes. Additionally, topological properties of hubs
do not in general correlate with co-expression. Thus, we suggest that a
date/party dichotomy is not meaningful and it might be more useful to conceive
of roles for protein-protein interactions rather than individual proteins. We
find significant correlations between interaction centrality and the functional
similarity of the interacting proteins.Comment: 27 pages, 5 main figures, 4 supplementary figure
Fifteen years SIB Swiss Institute of Bioinformatics: life science databases, tools and support.
The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) was created in 1998 as an institution to foster excellence in bioinformatics. It is renowned worldwide for its databases and software tools, such as UniProtKB/Swiss-Prot, PROSITE, SWISS-MODEL, STRING, etc, that are all accessible on ExPASy.org, SIB's Bioinformatics Resource Portal. This article provides an overview of the scientific and training resources SIB has consistently been offering to the life science community for more than 15 years
The Binary Protein Interactome of Treponema pallidum – The Syphilis Spirochete
Protein interaction networks shed light on the global organization of proteomes but can also place individual proteins into a functional context. If we know the function of bacterial proteins we will be able to understand how these species have adapted to diverse environments including many extreme habitats. Here we present the protein interaction network for the syphilis spirochete Treponema pallidum which encodes 1,039 proteins, 726 (or 70%) of which interact via 3,649 interactions as revealed by systematic yeast two-hybrid screens. A high-confidence subset of 991 interactions links 576 proteins. To derive further biological insights from our data, we constructed an integrated network of proteins involved in DNA metabolism. Combining our data with additional evidences, we provide improved annotations for at least 18 proteins (including TP0004, TP0050, and TP0183 which are suggested to be involved in DNA metabolism). We estimate that this “minimal” bacterium contains on the order of 3,000 protein interactions. Profiles of functional interconnections indicate that bacterial proteins interact more promiscuously than eukaryotic proteins, reflecting the non-compartmentalized structure of the bacterial cell. Using our high-confidence interactions, we also predict 417,329 homologous interactions (“interologs”) for 372 completely sequenced genomes and provide evidence that at least one third of them can be experimentally confirmed
Structure and Evolution of Streptomyces Interaction Networks in Soil and In Silico
Soil grains harbor an astonishing diversity of Streptomyces strains producing diverse secondary metabolites. However, it is not understood how this genotypic and chemical diversity is ecologically maintained. While secondary metabolites are known to mediate signaling and warfare among strains, no systematic measurement of the resulting interaction networks has been available. We developed a high-throughput platform to measure all pairwise interactions among 64 Streptomyces strains isolated from several individual grains of soil. We acquired more than 10,000 time-lapse movies of colony development of each isolate on media containing compounds produced by each of the other isolates. We observed a rich set of such sender-receiver interactions, including inhibition and promotion of growth and aerial mycelium formation. The probability that two random isolates interact is balanced; it is neither close to zero nor one. The interactions are not random: the distribution of the number of interactions per sender is bimodal and there is enrichment for reciprocity—if strain A inhibits or promotes B, it is likely that B also inhibits or promotes A. Such reciprocity is further enriched in strains derived from the same soil grain, suggesting that it may be a property of coexisting communities. Interactions appear to evolve rapidly: isolates with identical 16S rRNA sequences can have very different interaction patterns. A simple eco-evolutionary model of bacteria interacting through antibiotic production shows how fast evolution of production and resistance can lead to the observed statistical properties of the network. In the model, communities are evolutionarily unstable—they are constantly being invaded by strains with new sets of interactions. This combination of experimental and theoretical observations suggests that diverse Streptomyces communities do not represent a stable ecological state but an intrinsically dynamic eco-evolutionary phenomenon
Interactome and Gene Ontology provide congruent yet subtly different views of a eukaryotic cell
15 pages, 6 figures.-- 19604360 [PubMed]BACKGROUND: The characterization of the global functional structure of a cell is a major goal in bioinformatics and systems biology. Gene Ontology (GO) and the protein-protein interaction network offer alternative views of that structure. RESULTS: This study presents a comparison of the global structures of the Gene Ontology and the interactome of Saccharomyces cerevisiae. Sensitive, unsupervised methods of clustering applied to a large fraction of the proteome led to establish a GO-interactome correlation value of +0.47 for a general dataset that contains both high and low-confidence interactions and +0.58 for a smaller, high-confidence dataset. CONCLUSION: The structures of the yeast cell deduced from GO and interactome are substantially congruent. However, some significant differences were also detected, which may contribute to a better understanding of cell function and also to a refinement of the current ontologiesResearch supported by grant BIO2008-05067 (Programa Nacional de Biotecnología;
Ministerio de Ciencia e Innovación. Spain), awarded to IM. AM was a FPI fellow from Ministerio de Educación y Ciencia (Spain).Peer reviewe
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