MUC4 involvement in ErbB2/ErbB3 phosphorylation and signaling in response to airway cell mechanical injury

The receptor tyrosine kinases ErbB2 and ErbB3 are phosphorylated in response to injury of the airway epithelium. Since we have shown that the membrane mucin MUC4 can act as a ligand/modulator for ErbB2, affecting its localization in polarized epithelial cells and its phosphorylation, we questioned whether Muc4 was involved, along with ErbB2 and ErbB3, in the damage response of airway epithelia. To test this hypothesis, we first examined the localization of MUC4 in human airway samples. Both immunocytochemistry and immunofluorescence showed a co‐localization of MUC4 and ErbB2 at the airway luminal surface. Sequential immunoprecipitation and immunoblotting from airway cells demonstrated that the MUC4 and ErbB2 are present as a complex in airway epithelial cells. To assess the participation of MUC4 in the damage response, cultures of NCI‐H292 or airway cells were scratch‐wounded, then analyzed for association of phospho‐ErbB2 and ‐ErbB3 with MUC4 by sequential immunoprecipitation and immunoblotting. Wounded cultures exhibited increased phosphorylation of both receptors in complex with MUC4. Scratch wounding also increased activation of the downstream pathway through Akt, as predicted from our previous studies on Muc4 effects on ErbB2 and ErbB3. The participation of MUC4 in the phosphorylation response was also indicated by siRNA repression of MUC4 expression, which resulted in diminution of the phosphorylation of ErbB2 and ErbB3. These studies provide a new model for the airway epithelial damage response, in which the MUC4–ErbB2 complex is a key element in the sensor mechanism and phosphorylation of the receptors. J. Cell. Biochem. 107: 112–122, 2009. © 2009 Wiley‐Liss, Inc.     

An endogenous ligand for the central sulfonylurea receptor

An endogenous ligand for the rat central sulfonylurea receptor has been evidenced in the rat central nervous system. The characteristics of this ligand (extractibility, non-dialysability, chromatographic behaviour on different media, sensitivity to proteases) indicate that it is a neutral to slightly basic peptide.     

Biologie des Eleonorenfalken(Falco eleonorae): 10. Der Einflu? der Horstlage auf den Bruterfolg

Zusammenfassung Der Bruterfolg des Eleonorenfalken wurde auf einer ägäischen Inselkolonie in Relation zur Horstlage untersucht. Bei Horsten mit Gratlage auf übersichtlichem Gelände war er signifikant höher (1,8 Junge/Horst) als bei den übrigen Horsten mit z. T. schlechtem Geländeüberblick (1,3 Junge/Horst). Da alle Horste gegenüber den NW-Winden geschützt lagen, waren die meisten an südlich ausgerichteten Hängen potentiell der intensiven Sonneneinstrahlung ausgesetzt. In den Horstrevieren von typisch 20 m Durchmesser gab es aber nicht immer vor Sonne geschützte Horsthöhlen, so daß bei Lufttemperaturen von 40 °C und Bodentemperaturen von bis zu 60 °C die Embryonen in den Eiern gefährdet sein können, besonders, wenn sie der direkten Sonneneinstrahlung ausgesetzt sind. Dies tritt z. B. bei einer Störung in der Brutkolonie ein. Der Bruterfolg in den sonnenexponierten Höhlen lag mit 0,8–1,3 Junge/Horst signifikant niedriger als in den sonnengeschützten Höhlen mit durchschnittlich 1,75 Junge/Horst. Neben einer normalen Infertilität von 10 % fielen weitere 8 % aller Eier in der Brutkolonie durch Sonneneinwirkung aus.

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Biology of the Eleonora's Falcon(Falco eleonorae): 10. Breeding success in relation to nest site exposition

Summary Breeding success of the Eleonora's Falcon was studied in an Aegean island colony. In nests near cliff tops with an unobstructed view of the surroundings, a significantly higher breeding success (1.8 pulli/nest) was obtained than in other nests (1.3 pulli/nest). Since all nests were chosen protected from the wind, and as the main wind comes from NW, most nests were situated on southern slopes and are thus potentially exposed to the sun. Within a falcon territory of typically 20 m diameter in size there was not always a lime stone crevice with complete shade for the eggs. At an air temperature of 40 °C and a soil temperature of up to 60 °C, excessive sunning of an unprotected egg can be lethal for the falcon embryo. Breeding success in sun exposed nests was significantly lower (0.8–1.3 pulli/nest) than in sheltered nests (1.75 pulli/nest). In addition to a normal infertility of 10 %, about 8 % of all eggs laid were lost due to sun irradiation.

     

Second-harmonic generation in monolayers of hemicyanine dyes at the air/water interface: Observation of chemical degradation

In situ studies of second-harmonic generation (SHG) in monolayers of pure hemicyanine dyes and their mixtures with arachidic acid at the air/water interface were performed. The studies revealed an unexpected chemical instability of the hemicyanine dyes involving a cleavage of the stilbene double bond when deposited onto the water surface. This reaction occurred especially rapidly in the presence of the arachidic acid. Dilution with arachidic acid did not lead to a significant enhancement of the harmonic intensity.     

Influence of prior and visual information on eye movements in amblyopic children

This study analyzed the characteristics of pursuit and assessed the influence of prior and visual information on eye velocity and saccades in amblyopic and control children, in comparison to adults. Eye movements of 41 children (21 amblyopes and 20 controls) were compared to eye movements of 55 adults (18 amblyopes and 37 controls). Participants were asked to pursue a target moving at a constant velocity. The target was either a ‘standard’ target, with a uniform color intensity, or a ‘noisy’ target, with blurry edges, to mimic the blurriness of an amblyopic eye. Analysis of pursuit patterns showed that the onset was delayed, and the gain was decreased in control children with a noisy target in comparison to amblyopic or control children with a standard target. Furthermore, a significant effect of prior and visual information on pursuit velocity and saccades was found across all participants. Moreover, the modulation of the effect of visual information on the pursuit velocity by group, that is amblyopes or controls with a standard target, and controls with a noisy target, was more limited in children. In other words, the effect of visual information was higher in control adults with a standard target compared to control children with the same target. However, in the case of a blurry target, either in control participants with a noisy target or in amblyopic participants with a standard target, the effect of visual information was larger in children.

     

Identifying conversion efficiency as a key mechanism underlying food webs adaptive evolution: a step forward,or backward?

Body size or mass is one of the main factors underlying food webs structure. A large number of evolutionary models have shown that indeed, the adaptive evolution of body size (or mass) can give rise to hierarchically organised trophic levels with complex between and within trophic interactions. However, these models generally make strong arbitrary assumptions on how traits evolve, casting doubts on their robustness. In particular, biomass conversion efficiency is always considered independent of the predator and prey size, which contradicts with the literature. In this paper, we propose a general model encompassing most previous models which allows to show that relaxing arbitrary assumptions gives rise to unrealistic food webs. We then show that considering biomass conversion efficiency dependent on species size is certainly key for food webs adaptive evolution because realistic food webs can evolve, making obsolete the need of arbitrary constraints on traits' evolution. We finally conclude that, on the one hand, ecologists should pay attention to how biomass flows into food webs in models. On the other hand, we question more generally the robustness of evolutionary models for the study of food webs.