Postnatal changes in phosphatase and non-specific esterase activity in the large intestine of the rat

Zusammenfassung Phosphatasen- und Esterasenaktivität in Enterozyten des Rattendickdarms ändert sich während der postnatalen Entwicklung. Alkalische und saure Phosphatase ist bei neugeborenen und jungen Ratten im oralen Dickdarmabschnitt stark positiv. Die Annahme der Beteiligung des Dickdarmes an Resorption und Metabolismus wird vorausgesetzt.     

Effect of ouabain on the active potassium accumulation

Zusammenfassung 10^–5–10^–6 M Ouabain hemmt die aktive K-Akkumulation in Gehirnrindenschnitten von Meerschweinchen und im ATP-angereicherten Erythrocytenstroma. Die Versuche weisen darauf hin, dass Ouabain, infolge seiner lipophilen Struktur, fest an die Zellmembran gebunden ist und den in der Membran befindlichen Carrier der « Transport-ATPase » blockiert.     

The apparent expansion of the inulin space in the nephrectomized dog

Zusammenfassung Der Verteilungsraum des Inulins beim nephrektomierten Hund am Operationstag wurde bei 17% des Körpergewichts gefunden. In den nächsten Tagen verminderte sich die Seruminulinkonzentration fortlaufend, unter scheinbarer Vergrösserung des Verteilungsraumes. Am 3. bis 5. Tag wurden einige Tiere erneut oder zum ersten Mal mit Inulin belastet, und es konnte festgestellt werden, dass keine wirkliche Vergrösserung des Verteilungsraumes eintritt. Für die Verminderung der Serumkonzentration wird auf Grund vonJancós Untersuchungen eine intrazelluläre Speicherung als wahrscheinlich angenommen.     

Psychotogenic and hallucinogenic properties of large doses of benactyzine

Zusammenfassung Benactyzin in Dosen 50–200 mg löste bei 7 Versuchspersonen experimentelle Psychose mit gleichzeitiger Herabsetzung von 5-Hydroxyindolylessigsäure im Harn aus. Die psychotogene Wirkung wird mit dem Eingriff in den Serotonin- und Acetylcholinmetabolismus erklärt.     

The use of dipeptide-p-nitranilides for the study of aminopeptidase specificity.

The use of dipeptide-p-nitranilides for the study of 2 placental aminopeptidases separated on Sephadex G200 helped in establishing some regular features of their specifities. The high-molecular (320,000 daltons) one prefers Phe in position P'1 to Leu, whereas the lower-molecular aminopeptidase (145,000 daltons) prefers Leu. The high-molecular aminopeptidase splits very slowly the N-terminal Leu when Gly is in adjacent position. Leu-Gly-p-NA is therefore an inhibitor of this AP.     

Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia

The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57?±?2 per cent) the sedimentary carbon budget of the ESAS, the world’s largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44?±?10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66?±?16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.     

Liquid-crystal-mediated self-assembly at nanodroplet interfaces

Technological applications of liquid crystals have generally relied on control of molecular orientation at a surface or an interface. Such control has been achieved through topography, chemistry and the adsorption of monolayers or surfactants. The role of the substrate or interface has been to impart order over visible length scales and to confine the liquid crystal in a device. Here, we report results from a computational study of a liquid-crystal-based system in which the opposite is true: the liquid crystal is used to impart order on the interfacial arrangement of a surfactant. Recent experiments on macroscopic interfaces have hinted that an interfacial coupling between bulk liquid crystal and surfactant can lead to a two-dimensional phase separation of the surfactant at the interface, but have not had the resolution to measure the structure of the resulting phases. To enhance that coupling, we consider the limit of nanodroplets, the interfaces of which are decorated with surfactant molecules that promote local perpendicular orientation of mesogens within the droplet. In the absence of surfactant, mesogens at the interface are all parallel to that interface. As the droplet is cooled, the mesogens undergo a transition from a disordered (isotropic) to an ordered (nematic or smectic) liquid-crystal phase. As this happens, mesogens within the droplet cause a transition of the surfactant at the interface, which forms new ordered nanophases with morphologies dependent on surfactant concentration. Such nanophases are reminiscent of those encountered in block copolymers, and include circular, striped and worm-like patterns.     

A novel putative auxin carrier family regulates intracellular auxin homeostasis in plants

The phytohormone auxin acts as a prominent signal, providing, by its local accumulation or depletion in selected cells, a spatial and temporal reference for changes in the developmental program. The distribution of auxin depends on both auxin metabolism (biosynthesis, conjugation and degradation) and cellular auxin transport. We identified in silico a novel putative auxin transport facilitator family, called PIN-LIKES (PILS). Here we illustrate that PILS proteins are required for auxin-dependent regulation of plant growth by determining the cellular sensitivity to auxin. PILS proteins regulate intracellular auxin accumulation at the endoplasmic reticulum and thus auxin availability for nuclear auxin signalling. PILS activity affects the level of endogenous auxin indole-3-acetic acid (IAA), presumably via intracellular accumulation and metabolism. Our findings reveal that the transport machinery to compartmentalize auxin within the cell is of an unexpected molecular complexity and demonstrate this compartmentalization to be functionally important for a number of developmental processes.