Mikroanalytische Bestimmung von Juvenilhormonen

Different techniques like bioassay, radioimmuno assay, and gas chromatography combined mass spectrometry are in use for a quantitative estimation ofjuvenile hormones in biological samples. Microderivatization of the characteristic epoxy group combined with adsorption on and selective desorption from alumina turns out to be sensitive enough for measuring juvenile hormone titers in the picomole range. With this technique, a first titer curve is shown for the developmental period of the fruit fly, Drosophila melanogaster, and for individuals of the desert locust, Locusta migratoria, as examples for the high sensitivity of this new analytical method

ojoplano-mediated basal constriction is essential for optic cup morphogenesis

11 páginas, 7 figuras. To the memory of Dr José-Santiago Martínez-Vinjoy. Supplementary material for this article is available at http://dev.biologists.org/cgi/content/full/136/13/2165/DC1Although the vertebrate retina is a well-studied paradigm for organogenesis, the morphogenetic mechanisms that carve the architecture of the vertebrate optic cup remain largely unknown. Understanding how the hemispheric shape of an eye is formed requires addressing the fundamental problem of how individual cell behaviour is coordinated to direct epithelial morphogenesis. Here, we analyze the role of ojoplano (opo), an uncharacterized gene whose human ortholog is associated with orofacial clefting syndrome, in the morphogenesis of epithelial tissues. Most notably, when opo is mutated in medaka fish, optic cup folding is impaired. We characterize optic cup morphogenesis in vivo and determine at the cellular level how opo affects this process. opo encodes a developmentally regulated transmembrane protein that localizes to compartments of the secretory pathway and to basal end-feet of the neuroepithelial precursors. We show that Opo regulates the polarized localization of focal adhesion components to the basal cell surface. Furthermore, tissue-specific interference with integrin-adhesive function impairs optic cup folding, resembling the ocular phenotype observed in opo mutants. We propose a model of retinal morphogenesis whereby opo-mediated formation of focal contacts is required to transmit the mechanical tensions that drive the macroscopic folding of the vertebrate optic cup.This work was supported by grants from the Deutsche Forschungsgemeinschaft, Collaborative Research Centre 488, the EU and HFSPO to J.W.; and MEC:BFU2008-04362/BMC to J.R.M.-M.Peer reviewe

Dimensioni dei corpora allata, titolo dell'ormone giovanile III, sviluppo degli oociti terminali e subterminali nel corso del periodo riproduttivo di Aiolopus thalassinus (Orthopteroidea Caelifera Acrididae )

È stato studiato l'effetto dei fattori che controllano la riproduzione in una popolazione di Aiolopus thalassinus (Fabricius, 1781), nativo dell'Africa orientale e allevato in condizioni di laboratorio controllate, ad Hannover. I parametri riproduttivi, quali numero degli ovarioli, periodo di preovideposizione, numero di ooteche per femmina, modifiche nel volume dei corpora allata (CA), titolo dell'ormone giovanile (JH) nell'emolinfa, sviluppo degli oociti terminali e subterminali, sono stati studiati nel corso del periodo di ovideposizione. Per i dati di ogni parametro riproduttivo sono state utilizzate da 58 a 103 femmine e sono stati valutati piu di 22 cicli gonadotrofici per ogni femmina. Nessuna correlazione è stata trovata tra il volume dei CA e l'età delle femmine adulte, così come tra questi parametri e le dimensioni degli oociti. Il titolo JH-III nell'emolinfa è stato basso (< 0.2 .pmol/10 μl) durante la previtellogenesi, aumenta successivamente fino ad un valore massimo di 2,5 pmol/10 μl, declinando drasticamente con la maturazione degli oociti e al momento dell'ovideposizione. Dopo la prima ovideposizione, il titolo dell'JH-111 nell'emolinfa aumenta nuovamente con lo sviluppo degli oociti nel corso del ciclo gonadotrofico, ma non ha inizio dal basso livello trovato durante la previtellogenesi e non raggiunge gli alti valori registrati precedentemente alla prima ovideposizione, quando il volume dei t-oociti aumenta. Lo sviluppo degli oociti subterminali spesso inizia prima dell'ovideposizione dei t-oociti. Il titolo di JH-III di questi individui non declina drasticamente. La simultanea maturazione di due generazioni di oociti può determinare un intervallo di soli 1-2 giornitra due ovideposizioni. Prima del completamento di due cicli gonadotrofici, il titolo JH-III declina nuovamente, ma non si è trovata una chiara ciclizzazione del titolo JH-III nell'emolinfa. In condizioni di laboratorio A. thalassinus risulta molto fecondo, con una media di 36 ovarioli e la possibilità di depositare più di 20 ooteche per femmina. Il volume dei CA varia indipendentemente dal titolo delIJ-111 dell'emolionfa e non può essere considerato un sicuro indice di riferimento per quest'ultimo. L'incremento di volume dei CA, accompagnato da un simultaneo innalzamento del titolo dell'JH dell'emolinfa, può essere osservato solo nei primi 15 giorni dopo lo sfarfallamento. In alcune femmine non si è notato sviluppo degli oociti né prima, né dopo la prima ovideposizione, anche se alcune di questa hanno evidenziato un titolo di JH-III nell'emolinfa molto elevato.In a population of Aiolopus thalassinus (Fabricius, 1781), originated from East Africa, (Kenya), and reared successfully under controlled laboratory conditions at Hannover, the effects of factors controlling reproduction were investigated. The reproductive parameters, like the number of ovariols, period of preoviposition, number of egg pods per female, as well as the changes in the volume of corpora allata (CA), the juvenile hormone (JH) titre of the haemolymph, and the growth of the terminal (t) and subterminal oocytes were studied throughout the egg-laying period. For the data of each reproductive parameter, 58-103 females were used. Up to 22 consecutive gonadotropic cycles per female were evaluated. Neither a correlation was found between the volume of CA and the age of the adult females, nor between these parameters and the size of the t-oocytes. The JH-III titre of the haemolymph was low (< 0.2 pmol/10 μl) during previtellogenesis, increasing after that to a maximum of 2.5 pmol/10 μland declining drastically with the maturation of the oocytes and the onset of oviposition. After the first egg deposition, the JH-III titre of the haemolymph increased again with the growth of the oocytes in the gonadotropic cycles, but did not start from that low level found during previtellogenesis, and did not show the high values recorded before the first oviposition, when the volume of t-oocytes increased. The growth of the subterminated oocytes often started before deposition of the t-oocytes. The JH-III titre of these individuals did not drastically decline. The simultaneous ripening of two generations of oocytes might account for the short interval of only one or two days passing between two ovipositions. Before the termination of the 2nd gonadotropic cycle, the JH-III titre declined again, but no clear cyclisation of the JH-III titre was found in the haemolyph. Under laboratory conditions, the East African A. thalassinus showed a high fecundity with an average of 36 ovarioles and the possibility to deposite more than 20 egg pods per female. The CA volume varied independently of the JH-III titre of the haemolymph and cannot be considered as a reliable indicator for the latter. The increase of the CA volume, accompanied by a simultaneous rise of the JH titre of the haemolyph, could only be observed during the first 15 days after emergence. In some females, a growth of oocytes was found neither before nor after the first oviposition, even though some of them had a very high JH-III titre in the haemolymph

A non-hybrid method for the PDF equations of turbulent flows on unstructured grids

In probability density function (PDF) methods of turbulent flows, the joint PDF of several flow variables is computed by numerically integrating a system of stochastic differential equations for Lagrangian particles. A set of parallel algorithms is proposed to provide an efficient solution of the PDF transport equation, modeling the joint PDF of turbulent velocity, frequency and concentration of a passive scalar in geometrically complex configurations. An unstructured Eulerian grid is employed to extract Eulerian statistics, to solve for quantities represented at fixed locations of the domain (e.g. the mean pressure) and to track particles. All three aspects regarding the grid make use of the finite element method (FEM) employing the simplest linear FEM shape functions. To model the small-scale mixing of the transported scalar, the interaction by exchange with the conditional mean model is adopted. An adaptive algorithm that computes the velocity-conditioned scalar mean is proposed that homogenizes the statistical error over the sample space with no assumption on the shape of the underlying velocity PDF. Compared to other hybrid particle-in-cell approaches for the PDF equations, the current methodology is consistent without the need for consistency conditions. The algorithm is tested by computing the dispersion of passive scalars released from concentrated sources in two different turbulent flows: the fully developed turbulent channel flow and a street canyon (or cavity) flow. Algorithmic details on estimating conditional and unconditional statistics, particle tracking and particle-number control are presented in detail. Relevant aspects of performance and parallelism on cache-based shared memory machines are discussed.Comment: Accepted in Journal of Computational Physics, Feb. 20, 200

Genuine Correlations of Like-Sign Particles in Hadronic Z0 Decays

Correlations among hadrons with the same electric charge produced in Z0 decays are studied using the high statistics data collected from 1991 through 1995 with the OPAL detector at LEP. Normalized factorial cumulants up to fourth order are used to measure genuine particle correlations as a function of the size of phase space domains in rapidity, azimuthal angle and transverse momentum. Both all-charge and like-sign particle combinations show strong positive genuine correlations. One-dimensional cumulants initially increase rapidly with decreasing size of the phase space cells but saturate quickly. In contrast, cumulants in two- and three-dimensional domains continue to increase. The strong rise of the cumulants for all-charge multiplets is increasingly driven by that of like-sign multiplets. This points to the likely influence of Bose-Einstein correlations. Some of the recently proposed algorithms to simulate Bose-Einstein effects, implemented in the Monte Carlo model PYTHIA, are found to reproduce reasonably well the measured second- and higher-order correlations between particles with the same charge as well as those in all-charge particle multiplets.Comment: 26 pages, 6 figures, Submitted to Phys. Lett.

Alexander von Humboldt: Wissenschaften zusammendenken

Wissenschaften zusammendenken – dies ist ein Leitmotiv in Alexander von Humboldts problemorientierter Forschung. In diesem Sinn versammelt der vorliegende Band eine Reihe von Beiträgen, die sich aus der Sicht verschiedener Fächer heute mit dieser Forschung auseinandersetzen, in den Sciences ebenso wie in den Humanities. Die Perspektiven reichen von Klimaforschung, Ökologie, Botanik, Zoologie und Vulkanologie bis zu Geschichte, Wissenschaftsgeschichte, Kunstgeschichte, Kartografie, Literaturwissenschaft und Museologie.Elf Aufsätze diskutieren Humboldts Beiträge zum Verständnis von Temperaturveränderungen sowie Landschaften und Arten. Sie entschlüsseln seine Zeichnungen, Karten und Infografiken, sie führen uns in das Berlin seiner Jugend, auf die Spuren wandernder Pflanzen und auf die Gipfel andiner Vulkane.Thinking the sciences together - this is a leitmotif of Alexander von Humboldt\u27s problem-oriented research. With this in mind, this volume brings together a series of contributions that deal with this research today from the perspective of various disciplines, in the sciences as well as in the humanities. The perspectives range from climate research, ecology, botany, zoology and volcanology to history, history of science, art history, cartography, literary studies and museology. Eleven essays discuss Humboldt\u27s contributions to the understanding of temperature changes, landscapes and species. They decipher his drawings, maps and infographics, they take us to the Berlin of his youth, on the trail of migrating plants and to the summits of Andean volcanoes.Penser ensemble les sciences - c\u27est un leitmotiv dans la recherche orientée vers les problèmes d\u27Alexander von Humboldt. C\u27est dans cet esprit que le présent ouvrage rassemble une série de contributions qui, du point de vue de différentes disciplines, se penchent aujourd\u27hui sur cette recherche, tant en sciences qu\u27en sciences humaines. Les perspectives vont de la climatologie, l\u27écologie, la botanique, la zoologie et la volcanologie à l\u27histoire, l\u27histoire des sciences, l\u27histoire de l\u27art, la cartographie, la littérature et la muséologie. Onze essais discutent des contributions de Humboldt à la compréhension des changements de température ainsi que des paysages et des espèces. Ils décryptent ses dessins, ses cartes et ses infographies, ils nous emmènent dans le Berlin de sa jeunesse, sur les traces des plantes migratrices et sur les sommets des volcans andins

Alexander von Humboldt: Wissenschaften zusammendenken

Wissenschaften zusammendenken – dies ist ein Leitmotiv in Alexander von Humboldts problemorientierter Forschung. In diesem Sinn versammelt der vorliegende Band eine Reihe von Beiträgen, die sich aus der Sicht verschiedener Fächer heute mit dieser Forschung auseinandersetzen, in den Sciences ebenso wie in den Humanities. Die Perspektiven reichen von Klimaforschung, Ökologie, Botanik, Zoologie und Vulkanologie bis zu Geschichte, Wissenschaftsgeschichte, Kunstgeschichte, Kartografie, Literaturwissenschaft und Museologie.Elf Aufsätze diskutieren Humboldts Beiträge zum Verständnis von Temperaturveränderungen sowie Landschaften und Arten. Sie entschlüsseln seine Zeichnungen, Karten und Infografiken, sie führen uns in das Berlin seiner Jugend, auf die Spuren wandernder Pflanzen und auf die Gipfel andiner Vulkane.Thinking the sciences together - this is a leitmotif of Alexander von Humboldt\u27s problem-oriented research. With this in mind, this volume brings together a series of contributions that deal with this research today from the perspective of various disciplines, in the sciences as well as in the humanities. The perspectives range from climate research, ecology, botany, zoology and volcanology to history, history of science, art history, cartography, literary studies and museology. Eleven essays discuss Humboldt\u27s contributions to the understanding of temperature changes, landscapes and species. They decipher his drawings, maps and infographics, they take us to the Berlin of his youth, on the trail of migrating plants and to the summits of Andean volcanoes.Penser ensemble les sciences - c\u27est un leitmotiv dans la recherche orientée vers les problèmes d\u27Alexander von Humboldt. C\u27est dans cet esprit que le présent ouvrage rassemble une série de contributions qui, du point de vue de différentes disciplines, se penchent aujourd\u27hui sur cette recherche, tant en sciences qu\u27en sciences humaines. Les perspectives vont de la climatologie, l\u27écologie, la botanique, la zoologie et la volcanologie à l\u27histoire, l\u27histoire des sciences, l\u27histoire de l\u27art, la cartographie, la littérature et la muséologie. Onze essais discutent des contributions de Humboldt à la compréhension des changements de température ainsi que des paysages et des espèces. Ils décryptent ses dessins, ses cartes et ses infographies, ils nous emmènent dans le Berlin de sa jeunesse, sur les traces des plantes migratrices et sur les sommets des volcans andins

Alexander von Humboldt: Wissenschaften zusammendenken

Wissenschaften zusammendenken – dies ist ein Leitmotiv in Alexander von Humboldts problemorientierter Forschung. In diesem Sinn versammelt der vorliegende Band eine Reihe von Beiträgen, die sich aus der Sicht verschiedener Fächer heute mit dieser Forschung auseinandersetzen, in den Sciences ebenso wie in den Humanities. Die Perspektiven reichen von Klimaforschung, Ökologie, Botanik, Zoologie und Vulkanologie bis zu Geschichte, Wissenschaftsgeschichte, Kunstgeschichte, Kartografie, Literaturwissenschaft und Museologie.Elf Aufsätze diskutieren Humboldts Beiträge zum Verständnis von Temperaturveränderungen sowie Landschaften und Arten. Sie entschlüsseln seine Zeichnungen, Karten und Infografiken, sie führen uns in das Berlin seiner Jugend, auf die Spuren wandernder Pflanzen und auf die Gipfel andiner Vulkane.Thinking the sciences together - this is a leitmotif of Alexander von Humboldt\u27s problem-oriented research. With this in mind, this volume brings together a series of contributions that deal with this research today from the perspective of various disciplines, in the sciences as well as in the humanities. The perspectives range from climate research, ecology, botany, zoology and volcanology to history, history of science, art history, cartography, literary studies and museology. Eleven essays discuss Humboldt\u27s contributions to the understanding of temperature changes, landscapes and species. They decipher his drawings, maps and infographics, they take us to the Berlin of his youth, on the trail of migrating plants and to the summits of Andean volcanoes.Penser ensemble les sciences - c\u27est un leitmotiv dans la recherche orientée vers les problèmes d\u27Alexander von Humboldt. C\u27est dans cet esprit que le présent ouvrage rassemble une série de contributions qui, du point de vue de différentes disciplines, se penchent aujourd\u27hui sur cette recherche, tant en sciences qu\u27en sciences humaines. Les perspectives vont de la climatologie, l\u27écologie, la botanique, la zoologie et la volcanologie à l\u27histoire, l\u27histoire des sciences, l\u27histoire de l\u27art, la cartographie, la littérature et la muséologie. Onze essais discutent des contributions de Humboldt à la compréhension des changements de température ainsi que des paysages et des espèces. Ils décryptent ses dessins, ses cartes et ses infographies, ils nous emmènent dans le Berlin de sa jeunesse, sur les traces des plantes migratrices et sur les sommets des volcans andins

Alexander von Humboldt: Wissenschaften zusammendenken

Wissenschaften zusammendenken – dies ist ein Leitmotiv in Alexander von Humboldts problemorientierter Forschung. In diesem Sinn versammelt der vorliegende Band eine Reihe von Beiträgen, die sich aus der Sicht verschiedener Fächer heute mit dieser Forschung auseinandersetzen, in den Sciences ebenso wie in den Humanities. Die Perspektiven reichen von Klimaforschung, Ökologie, Botanik, Zoologie und Vulkanologie bis zu Geschichte, Wissenschaftsgeschichte, Kunstgeschichte, Kartografie, Literaturwissenschaft und Museologie.Elf Aufsätze diskutieren Humboldts Beiträge zum Verständnis von Temperaturveränderungen sowie Landschaften und Arten. Sie entschlüsseln seine Zeichnungen, Karten und Infografiken, sie führen uns in das Berlin seiner Jugend, auf die Spuren wandernder Pflanzen und auf die Gipfel andiner Vulkane.Thinking the sciences together - this is a leitmotif of Alexander von Humboldt\u27s problem-oriented research. With this in mind, this volume brings together a series of contributions that deal with this research today from the perspective of various disciplines, in the sciences as well as in the humanities. The perspectives range from climate research, ecology, botany, zoology and volcanology to history, history of science, art history, cartography, literary studies and museology. Eleven essays discuss Humboldt\u27s contributions to the understanding of temperature changes, landscapes and species. They decipher his drawings, maps and infographics, they take us to the Berlin of his youth, on the trail of migrating plants and to the summits of Andean volcanoes.Penser ensemble les sciences - c\u27est un leitmotiv dans la recherche orientée vers les problèmes d\u27Alexander von Humboldt. C\u27est dans cet esprit que le présent ouvrage rassemble une série de contributions qui, du point de vue de différentes disciplines, se penchent aujourd\u27hui sur cette recherche, tant en sciences qu\u27en sciences humaines. Les perspectives vont de la climatologie, l\u27écologie, la botanique, la zoologie et la volcanologie à l\u27histoire, l\u27histoire des sciences, l\u27histoire de l\u27art, la cartographie, la littérature et la muséologie. Onze essais discutent des contributions de Humboldt à la compréhension des changements de température ainsi que des paysages et des espèces. Ils décryptent ses dessins, ses cartes et ses infographies, ils nous emmènent dans le Berlin de sa jeunesse, sur les traces des plantes migratrices et sur les sommets des volcans andins