Stimulation of a glycosyl-phosphatidylinositol-specific phospholipase by insulin and the sulfonylurea, glimepiride, in rat adipocytes depends on increased glucose transport

Abstract. Lipoprotein lipase (LPL) and glycolipidanchored cAMP-binding ectoprotein (Gcel) are modified by glycosyl-phosphatidylinositol (GPI) in rat adipocytes, however, the linkage is potentially unstable. Incubation of the cells with either insulin (0.1-30 nM) or the sulfonylurea, glimepiride (0.5-20/zM), in the presence of glucose led to conversion of up to 35 and 20%, respectively, of the total amphiphilic LPL and Gcel to their hydrophilic versions. Inositol-phosphate was retained in the residual protein-linked anchor structure. This suggests cleavage of the GPI anchors by an endogenous GPI-specific insulin- and glimepiride-inducible phospholipase (GPI-PL). Despite cleavage, hydrophilic LPL and Creel remained membrane associated and were released only if a competitor, e.g., inositol-(cyclic)monophosphate, had been added. Other constituents of the GPI anchor (glucosamine and mannose) were less efficient. This suggests reat body of information exists regarding the structural diversity as well as the biosynthesis and posttranslational attachment of glycosyl-phosphatidylinositol (GPI) ~ structures (for recent reviews see Low, 1989; McConville et al., 1993). However, the functional significance of membrane anchorage via GPI structures versus transmembrane polypeptide domains is still a matter of debate. The accessibility of GPI molecules to cleavage by phospholipase [(G)PI-PL] opens the possibility of a regu-Address all correspondence to Dr. (;tinter Miiller, Hoechst AG Frankfurt

What does it take to evolve behaviorally complex organisms?

What genotypic features explain the evolvability of organisms that have to accomplish many different tasks? The genotype of behaviorally complex organisms may be more likely to encode modular neural architectures because neural modules dedicated to distinct tasks avoid neural interference, i.e., the arrival of conflicting messages for changing the value of connection weights during learning. However, if the connection weights for the various modules are genetically inherited, this raises the problem of genetic linkage: favorable mutations may fall on one portion of the genotype encoding one neural module and unfavorable mutations on another portion encoding another module. We show that this can prevent the genotype from reaching an adaptive optimum. This effect is different from other linkage effects described in the literature and we argue that it represents a new class of genetic constraints. Using simulations we show that sexual reproduction can alleviate the problem of genetic linkage by recombining separate modules all of which incorporate either favorable or unfavorable mutations. We speculate that this effect may contribute to the taxonomic prevalence of sexual reproduction among higher organisms. In addition to sexual recombination, the problem of genetic linkage for behaviorally complex organisms may be mitigated by entrusting evolution with the task of finding appropriate modular architectures and learning with the task of finding the appropriate connection weights for these architectures

Do Cosmic Rays Heat the Early Intergalactic Medium?

Cosmic rays (CRs) govern the energetics of present-day galaxies and might have also played a pivotal role during the Epoch of Reionization. In particular, energy deposition by low-energy ($E \lesssim 10$ MeV) CRs accelerated by the first supernovae, might have heated and ionized the neutral intergalactic medium (IGM) well before ($z \approx 20$) it was reionized, significantly adding to the similar effect by X-rays or dark matter annihilations. Using a simple, but physically motivated reionization model, and a thorough implementation of CR energy losses, we show that CRs contribute negligibly to IGM ionization, but heat it substantially, raising its temperature by $\Delta T=10-200$ K by $z=10$, depending on the CR injection spectrum. Whether this IGM pre-heating is uniform or clustered around the first galaxies depends on CR diffusion, in turn governed by the efficiency of self-confinement due to plasma streaming instabilities that we discuss in detail. This aspect is crucial to interpret future HI 21 cm observations which can be used to gain unique information on the strength and structure of early intergalactic magnetic fields, and the efficiency of CR acceleration by the first supernovae.Comment: 10 pages, 7 figure

Ultrafast Modification of the Polarity at LaAlO3_3/SrTiO3_3 Interfaces

Oxide growth with semiconductor-like accuracy has led to atomically precise thin films and interfaces that exhibit a plethora of phases and functionalities not found in the oxide bulk material. This yielded spectacular discoveries such as the conducting, magnetic or even superconducting LaAlO$_3$/SrTiO$_3$ interfaces separating two prototypical insulating perovskite materials. All these investigations, however, consider the static state at the interface, although studies on fast oxide interface dynamics would introduce a powerful degree of freedom to understanding the nature of the LaAlO$_3$/SrTiO$_3$ interface state. Here we show that the polarization state at the LaAlO$_3$/SrTiO$_3$ interface can be optically enhanced or attenuated within picoseconds. Our observations are explained by a model based on charge propagation effects in the interfacial vicinity and transient polarization buildup at the interface

Entwicklung ertragssicherer Saflor-Stämme mit hohen Ölgehalten für den ökologischen Anbau

Zur Entwicklung ölreicher, krankheitstoleranter Saflor-Stämme wurde ein in der ehemaligen Thüringer Zuchtstation Bendeleben in den 1930er Jahren entwickelter Stamm (nur ca. 25 % Ölgehalt, aber gute Krankheitsresistenz) im Gewächshaus mit der spanischen Sorte ‚Sepasa’ (bis 46 % Ölgehalt, aber hohe Botrytisanfälligkeit) frei abblühen gelassen. Die Auskreuzung betrug ca. 50 %. Aus der im Feld als Einzelpflanzen angebauten F2-Generation wurden 550 ertragreiche Pflanzen geerntet und von jeder Pflanze an 30 Körnern der durchschnittliche Schalenanteil ermittelt. Pflanzen mit einem Schalenanteil < 40 % sind im Feld nachgebaut worden (ca. 50 Nummern, Einzelpflanzenanbau, 30 x 30 cm, 5,4 m² Anbaufläche/Nachkommenschaft). Je eine Pflanze mit hohem Kornertrag und niedrigem durchschnittlichen Schalenanteil aus jeder Parzelle wurde für den nächstjährigen Anbau ausgewählt und gleichzeitig das Restsaatgut der 14 besten Parzellen (homogen, frühreif, ertragreich) für eine exakte Ertragsprüfung verwendet. Die Ermittlung des Schalenanteils an Einzelkörnern und –pflanzen hat sich als schnelle und preiswerte Methode zur Einschätzung des Ölgehaltes erwiesen (ermittelte Korrelation zwischen Ölgehalt und Schalenanteil r = 0,88). Technisch ist die Trennung von Schale und Kern leicht durch kurzzeitiges Einquellen der Samen in Wasser zu erreichen. In den bisher fünfjährigen Ertragsprüfungen mit Stämmen aus der Kreuzung ‚Sepasa’ und Stamm ‚Bendeleben’ hat sich gezeigt, dass diese der Standardsorte ‚Sabina’ in günstigen Jahren mit sonnigem und trockenem Wetter während der Blüte ertraglich überlegen sein können. Sie wiesen gleichzeitig einen im Durchschnitt 30 % höheren Ölgehalt als ‚Sabina’ auf. Die Stämme waren in morphologischer Hinsicht bereits in der F4 weitgehend homogen, enthielten aber noch viele botrytrisanfällige Pflanzen, wie sich 2007 zeigte. In diesem Jahr mit starkem Infektionsdruck waren bei zwei Drittel aller angebauten Stämme und Einzelpflanzennachkommenschaften (EPN) gravierende Ertragseinbußen festzustellen. Immerhin wiesen 15 EPN aber durchgängig keine Ertragsminderung bei gleichzeitig höherem Ölgehalt als ‚Sabina’ auf. Es ist also durchaus möglich, durch Einkreuzung von südeuropäischen oder amerikanischen Stämmen, die sich durchgehend in eigenen Prüfungen als botrytisanfällig erwiesen haben, in angepasste Typen, botrytistolerante Formen mit hohen Ölgehalten zu entwickeln. Als einfachste Methode zur Selektion von dünnschaligen, ölreichen Typen aus spaltenden Populationen hat sich die Isolation von ca. 20 Blütenköpfchen einer Pflanze mit Crispac-Tüten mit Supermicrolochung und Bestimmung deren genetischen Status an Einzelkörnern aus nichtisolierten Köpfchen derselben Pflanze erwiesen. Der Samenansatz unter Isolation ist allerdings gering und die Keimfähigkeit der Samen niedrig. Andere Methoden, wie die Auslese von Einzelpflanzen mit niedrigem Schalenanteil oder die Anzucht von schalenlosen Kernen mit hohem Ölgehalt führten nur zu einem partiellen Erfolg, so dass in den Ertragsprüfungen nur 37,6 % Ölgehalt bei einem Stamm erreicht werden konnten. Die Probleme des Safloranbaus unter mitteleuropäischen Bedingungen sind mit der Entwicklung botrytistoleranter ölreicher Stämme nicht gelöst. Eine ausreichende Befruchtung ist in kühlen und feuchten Jahren nicht gegeben, weil Saflor zwingend auf die Bestäubung durch Insekten angewiesen ist. Es kommt zur Bildung einer größeren Anzahl parthenokarper (= hohler) Samen, wodurch der Ertrag und insbesondere der Ölgehalt deutlich sinken. Die Erhöhung der Selbstfertilität muss deshalb zukünftig ein wichtiges Zuchtziel sein

Dynamic Functional ForceMeasurements on an Anterior Bite Plane during theNight

Abstract. : Background: : Anterior bite planes are used in removable and fixed appliance treatment. In removable appliance treatment the question arising is whether the delivered forces can achieve active intrusion in terms of their amplitude and duration. In fixed appliance treatment, the force effect on the incisors and associated pathologic side effects, in particular under the application of intrusion mechanics, have to be considered. Subjects and Method: : The aim of the present study was to investigate the effects of an anterior bite plane during the night. For this purpose ten subjects underwent nocturnal sleep investigations by means of a telemetric system. A silicon force sensor was integrated into an anterior bite plane for continuous measurement of bite forces and of the frequency of occlusal contact with the plate. Results: : The occlusal forces exerted on the anterior bite planes ranged between 3 and 80 N. The average forces were 5.5-24 N. The number of occlusal contacts varied between 39 and 558, with forces of between 7 and 9 N being registered in most cases. Major interindividual differences were detected in the magnitude of the force as well as in bite frequency. The intraindividual pattern of arising occlusal forces showed an intermittent force effect. No significant differences were found with regard to gender or growth pattern. Conclusions: : In subjects with removable appliances, no active intrusion of teeth is possible during the night owing to the small number of occlusal contacts. Due to the partially very high forces in fixed appliance therapy, the integration of an anterior bite plane has to be assessed as critical in patients with unfavorable root geometry or bruxis

FTIR-ATR Spectroscopic Analysis of Changes in Fiber Properties During Insulating Fiberboard Manufacture of Beech Wood

Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy was applied to trace changes in chemical fiber properties during the production process of insulating fiber mats. In combination with cluster analysis, FTIR spectra were used to interpret the homogeneity of the products. Beech wood (Fagus sylvatica L.) was used as a novel sustainable material for fiberboard production. The insulating fiberboards were either processed without binder or with potato pulp or potato starch as renewable binders and dried in a dryer or a microwave. FTIR spectral analyses revealed chemical modifications at the O-H association band of carbohydrates that distinguished the two different drying methods. Additions of plant-based renewable binders diminished the absorbance of the resulting products at characteristic wavenumbers in the IR. These decreases were closely correlated with the amount of added binder and thus have the potential to quantify binder additions to the fiberboards. Cluster analysis grouped FTIR spectra of samples from different production steps or processes correctly and therefore is an effective and simple technique for quality control of insulating fiberboards from renewable resources