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A paradigm for thinking about wholes, their constitution and re-production, has long been provided by living organisms. While the emphasis is often on the relation between parts and wholes - between the functionally differentiated organs and the organism, or, on a lower level, between cells and organs - Robert Meunier and Valentine Reynaud's essay 'The Innate Plasticity of Bodies and Minds: Integrating Models of Genetic Determination and Environmental Formation' poses the question of the whole in biology with respect to the organism and its environment. A developmental system involves not only what we conventionally discern as the organism, that is, initially, the fertilized egg and the cellular mass arising from it by cell division, but also the physical and biological surrounding of the developing embryo. In the sense that not every aspect of the environment plays a role, the organism as part of the system constitutes this whole by determining what has an effect on the process and what does not. On the other hand, by not only enabling development or providing material but instead shaping the process in specific ways, the whole of organism-environment interactions constitutes its part, i.e., the developing organism. If there are therefore different, potentially incommensurable constitutions of the whole developmental system, there are also different ways of identifying the relevant units of selection in evolution, such as the living organism as a whole or the genes as the units of replication. In their essay, Meunier and Reynaud argue for a view on development and evolution that integrates notions of environmental influence and genetic determination. The notion of plasticity that has recently gained currency in the life sciences seems to oppose genetic determination and innateness by underlining the importance of environmental influence. However, while morphological and cognitive development is indeed plastic and sensitive to the environment, the essay emphasizes that the mechanisms and elements enabling a system to respond to influences must be available for development to happen in the first place. These resources for development are not homogeneous 'stuff' that becomes formed by the environment through the course of development. Instead, they are highly structured and specific and thus enable specific responses to contextual conditions. Under varying conditions they will of course appear in different combinations and produce different outcomes. Thus, they enable plasticity. And yet, as they are specific mechanisms and elements, which mainly gain their specificity from the structure of the genetic material on which the environment can act, it appears appropriate to refer to them as innate.
Über das Eiablage Verhalten und die Faktoren, welche die Eiablage begünstigen, ist bei den meisten der fast 20000 Tenebrioniden nichts bekannt. Lediglich bei einigen wirtschaftlich wichtigen Arten gibt es dazu Untersuchungen (JAKOBS & RENNER 1988). Als eine der wasserärmsten Wüsten der Welt ist die Namib reich an endemischen Coleopteren – insbesondere 320 Tenebrionidaearten (HOLM & DE MEILLON 1996). Langzeituntersuchungen an Tenebrioniden (HENSCHEL 1994, HENSCHEL et al. 1998) legen die Vermutung nahe, dass Schwankungen der Populationen auf unterschiedliche Reproduktionsstrategien zurückzuführen sind. Klimatische Ereignisse, die der Namib Feuchtigkeit zuführen, sind für Entwicklung und Reproduktion besonders beachtenswert (NICOLSON 1990).
Bitter taste receptors (TAS2Rs) are expressed in mucous epithelial cells of the tongue but also outside the gustatory system in epithelial cells of the colon, stomach and bladder, in the upper respiratory tract, in the cornified squamous epithelium of the skin as well as in airway smooth muscle cells, in the testis and in the brain. In the present work we addressed the question if bitter taste receptors might also be expressed in other epithelial tissues as well. By staining a tissue microarray with 45 tissue spots from healthy human donors with an antibody directed against the best characterized bitter taste receptor TAS2R38, we observed an unexpected strong TAS2R38 expression in the amniotic epithelium, syncytiotrophoblast and decidua cells of the human placenta. To analyze the functionality we first determined the TAS2R38 expression in the placental cell line JEG-3. Stimulation of these cells with diphenidol, a clinically used antiemetic agent that binds TAS2Rs including TAS2R38, demonstrated the functionality of the TAS2Rs by inducing calcium influx. Restriction enzyme based detection of the TAS2R38 gene allele identified JEG-3 cells as PTC (phenylthiocarbamide)-taster cell line. Calcium influx induced by PTC in JEG-3 cells could be inhibited with the recently described TAS2R38 inhibitor probenecid and proved the specificity of the TAS2R38 activation. The expression of TAS2R38 in human placental tissues points to further new functions and hitherto unknown endogenous ligands of TAS2Rs far beyond bitter tasting.