109 research outputs found
Einleitung: Positionierungen. Kritische Antworten auf die „Flüchtlingskrise“ in Kunst und Literatur
Modern and Contemporary Studie
Introduction: Taking Positions on the “Refugee Crisis”: Critical Responses in Art and Literature
Modern and Contemporary Studie
Cooperation in Microbial Populations: Theory and Experimental Model Systems
Cooperative behavior, the costly provision of benefits to others, is common
across all domains of life. This review article discusses cooperative behavior
in the microbial world, mediated by the exchange of extracellular products
called public goods. We focus on model species for which the production of a
public good and the related growth disadvantage for the producing cells are
well described. To unveil the biological and ecological factors promoting the
emergence and stability of cooperative traits we take an interdisciplinary
perspective and review insights gained from both mathematical models and
well-controlled experimental model systems. Ecologically, we include crucial
aspects of the microbial life cycle into our analysis and particularly consider
population structures where an ensemble of local communities (sub populations)
continuously emerge, grow, and disappear again. Biologically, we explicitly
consider the synthesis and regulation of public good production. The discussion
of the theoretical approaches includes general evolutionary concepts,
population dynamics, and evolutionary game theory. As a specific but generic
biological example we consider populations of Pseudomonas putida and its
regulation and utilization of pyoverdines, iron scavenging molecules. The
review closes with an overview on cooperation in spatially extended systems and
also provides a critical assessment of the insights gained from the
experimental and theoretical studies discussed. Current challenges and
important new research opportunities are discussed, including the biochemical
regulation of public goods, more realistic ecological scenarios resembling
native environments, cell to cell signalling, and multi-species communities.Comment: Review article, 88 pages, 14 figure
Tomato: a crop species amenable to improvement by cellular and molecular methods
Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures.
In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.
In vivo and in vitro synthesis of CM-proteins (A-hordeins) from barley (Hordeum vulgare L.)
CM-proteins from barley endosperm (CMa, CMb, CMc, CMd), which are the main components of the A-hordein fraction, are synthesized most actively 10 to 30 d after anthesis (maximum at 15–20 d). They are synthesized by membranebound polysomes as precursors of higher apparent molecular weight (13,000–21,000) than the mature proteins (12,000–16,000). The largest in vitro product (21,000) is the putative precursor of protein CMd (16,000), as it is selected with anti-CMd monospecific IgG's, and is coded by an mRNA of greater sedimentation coefficient (9 S) than those encoding the other three proteins (7.5 S). CM-proteins always appear in the soluble fraction, following different homogenization and subcellular fractionation procedures, indicating that these proteins are transferred to the soluble fraction after processing
Evaluating the organisational climate in Italian public healthcare institutions by means of a questionnaire
<p>Abstract</p> <p>Background</p> <p>By means of the ICONAS project, the Healthcare Agency of an Italian Region developed, and used a standardised questionnaire to quantify the organisational climate. The aims of the project were (a) to investigate whether the healthcare institutions were interested in measuring climate, (b) to estimate the range of applicability and reliability of the instrument, (c) to analyse the dimensions of climate among healthcare personnel, (d) to assess the differences among employees with different contractual positions.</p> <p>Methods</p> <p>The anonymous questionnaire containing 50 items, each with a scale from 1 to 10, was offered to the healthcare organisations, to be compiled during ad hoc meetings. The data were sent to the central project coordinator. The differences between highly specialised staff (mostly physicians) and other employees were assessed after descriptive statistical analysis of the single items. Both Principal Component Analysis and Factor Analysis were used.</p> <p>Results</p> <p>Ten healthcare organisations agreed to partecipate. The questionnaire was completed by 8691 employees out of 13202. The mean value of organisational climate was 4.79 (range 1–10). There were significant differences among single items and between the 2 groups of employees. Multivariate methods showed: (a) one principal component explained > 40% of the variance, (b) 7 factors summarised the data.</p> <p>Conclusion</p> <p>Italian healthcare institutions are interested in assessing organisational phenomena, especially after the reforms of the nineties. The instrument was found to be applicable and suitable for measuring organisational climate. Administration of the questionnaire leads to an acceptable response rate. Climate can be discribed by means of 7 underlying dimensions.</p
An everlasting pioneer: the story of Antirrhinum research
Despite the tremendous success of
Arabidopsis thaliana, no single model can
represent the vast range of form that is
seen in the ~250,000 existing species of
flowering plants (angiosperms). Here,
we consider the history and future of an
alternative angiosperm model — the
snapdragon Antirrhinum majus. We ask
what made Antirrhinum attractive to the
earliest students of variation and
inheritance, and how its use led to
landmark advances in plant genetics and
to our present understanding of plant
development. Finally, we show how the
wide diversity of Antirrhinum species,
combined with classical and molecular
genetics — the two traditional strengths
of Antirrhinum — provide an opportunity
for developmental, evolutionary and
ecological approaches. These factors
make A. majus an ideal comparative
angiosperm
Crystal-field splitting and single-ion exchange of Ce and Yb impurities in dilute monopnictides
We report measurements on the resistivity, susceptibility and ESR vs. temperature of monopnictides MZ (with M=Sc, Y, La and Z=As, Sb, Bi) which contain small amounts of Ce- or Yb-ions as doping material. Metallic conductivities are found in all of these systems. With increasing covalent character of the MZ host we observed: an increasing conductivity, a decreasing crystal-field splitting of the Ce3+- or Yb3+-ionic state and for both 4f-ions an increase of the negative 4f-conduction electron exchange constant
Alcohol dehydrogenase whole-cell catalysts - A broad technology platform for life science applications
Osswald S, Doderer K, Gröger H, Wienand W. Alcohol dehydrogenase whole-cell catalysts - A broad technology platform for life science applications. CHIMICA OGGI-CHEMISTRY TODAY. 2007;25(5, S):16-18
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