Model evaluation for glycolytic oscillations in yeast biotransformations of xenobiotics

Anaerobic glycolysis in yeast perturbed by the reduction of xenobiotic ketones is studied numerically in two models which possess the same topology but different levels of complexity. By comparing both models' predictions for concentrations and fluxes as well as steady or oscillatory temporal behavior we answer the question what phenomena require what kind of minimum model abstraction. While mean concentrations and fluxes are predicted in agreement by both models we observe different domains of oscillatory behavior in parameter space. Generic properties of the glycolytic response to ketones are discussed

Exploring language as the “in-between”

Assuming a performative notion of language, this contribution addresses how language functions as a symbolic means and asks for its function for the dialogical self. In accordance with a non-individualistic notion, individuals are related to each other within and by virtue of an in-between. This in-between is called “spacetime of language”: a dynamic evolving across time, perceived as linguistic forms with their chronotopology and the positionings of the performers (self as-whom to other as-whom). With respect to the linguistic forms, the specificity of language functioning is described by Bühler’s term of displacement. The effect of displacement is to generate sharedness by inducing a movement the partners follow, going beyond their actual, sensitive contact. Symbolic displacement, expanding Bühler’s notion, is particularly interesting with regard to the dialogical self: it permits the social construction of several perspectives on self, other, and reality—positions and voices informing the self’s performances

PhytoGerm: extraction of germanium from biomass:an economic pre-feasibility study

Germanium is a metalloid with great potential for industrial use. Currently, the semiconductor is primarily recovered as a by-product during the exploitation of zinc. The global zinc mine and metal production, however, has been decreasing over the last years, which may result in a production to consumption deficit for germanium. “PhytoGerm” is part of the r³-initiative for tech metals and resource efficiency, a subsidy program of the German Federal Ministry of Education and Research. Within this context, the PhytoGerm project focuses on alternative methods to extract germanium. The suggested mining process operates with ribbon grass which is capable of accumulating germanium from soils, e.g. from mine tailings. After harvesting germanium-enriched plants, the biomass is ensiled and biogas is produced by fermentation. This study analyzes the economic pre-feasibility of this process, whereby the results reveal that germanium can be obtained economically by means of phytomining under certain preconditions (i.e. absorption of 10 ppm germanium in dry biomass, twice the current price of germanium(IV)-oxide)

Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis

<p>Abstract</p> <p>Background</p> <p>The nasal cavity of all vertebrates houses multiple chemosensors, either innervated by the Ist (olfactory) or the Vth (trigeminal) cranial nerve. Various types of receptor cells are present, either segregated in different compartments (e.g. in rodents) or mingled in one epithelium (e.g. fish). In addition, solitary chemosensory cells have been reported for several species. Alligators which seek their prey both above and under water have only one nasal compartment. Information about their olfactory epithelium is limited. Since alligators seem to detect both volatile and water-soluble odour cues, I tested whether different sensory cell types are present in the olfactory epithelium.</p> <p>Results</p> <p>Electron microscopy and immunocytochemistry were used to examine the sensory epithelium of the nasal cavity of the American alligator. Almost the entire nasal cavity is lined with olfactory (sensory) epithelium. Two types of olfactory sensory neurons are present. Both types bear cilia as well as microvilli at their apical endings and express the typical markers for olfactory neurons. The density of these olfactory neurons varies along the nasal cavity. In addition, solitary chemosensory cells innervated by trigeminal nerve fibres, are intermingled with olfactory sensory neurons. Solitary chemosensory cells express components of the PLC-transduction cascade found in solitary chemosensory cells in rodents.</p> <p>Conclusion</p> <p>The nasal cavity of the American alligator contains two different chemosensory systems incorporated in the same sensory epithelium: the olfactory system proper and solitary chemosensory cells. The olfactory system contains two morphological distinct types of ciliated olfactory receptor neurons.</p

Richtigstellung zum Artikel: 'Enantioselective Microbial Reduction with Baker's Yeast on an Industrial Scale'

Microbial synthesis is an important contribution to Green Chemistry and production-integrated environmental protection. The example of baker's yeast is used to demonstrate how microorganisms can be versatile reagents for asymmetric synthesis and how microbial technologies can be alternatives and complements to catalytic processes. The commercial viability of enantioselective microbial processes on an industrial scale is shown with the examples of (S)-3-hydroxybutyric acid ethylester (1), (2S,5S)-hexanediol (2) and (1R,2S)-cis-2-hydroxycyclohexane carboxylic acid ethylester (3). The investigation of several competing enzymatic pathways in the living cells during the reduction reaction allows the process to be controlled and makes this technology applicable for the large-scale commercial synthesis of 3