Ergosterol Effect on the Desaturation of 14C-Cis-Vaccenate in Tetrahymena

Supplement of ergosterol to the growth medium of the ciliated protozoan Tetrahymena pyriformis W leads to incorporation of the foreign sterol within cell membranes and suppression of synthesis of the native sterol-like compound tetrahymanol, as well as to changes in the fatty acid compositions of several major classes of membrane lipid. Alteration of fatty acid composition is thought to represent a regulatory mechanism whereby optimum membrane fluidity is maintained when the slightly dissimilar foreign sterol is added into the phospholipid bilayer of the membranes. The present study, using several different conditions of growth temperature, substrate concentrations and incubation time, and ergosterol concentrations and exposure time, is an attempt to provide evidence supporting a hypothetical regulatory mechanism. This mechanism proposes that there is a feedback regulation by membrane-bound sterol on an enzyme or enzymes involved in synthesis of the long chain fatty acids contained in membrane phospholipid. Such a mechanism could account for the balance between sterol and fatty acid content of membrane. The data presented here show that a statistically significant increase in desaturation of 14C-cis-vaccenate can be demonstrated in Tetrahymena cell cultures whose membranes contain the foreign sterol, when growth temperature is maintained at 20° or 29.5°. Tetrahymena desaturated 14C-cis-vaccenate substrate in both ergosterol supplemented and normal cultures. The 14C labeled product, 6,11-18:2 was recovered and separated by silver nitrate-Unisil column chromatography

PROSPECT: A comprehensive sample acquisition and analysis package for lunar science and exploration

PROSPECT is a comprehensive payload package developed by the European Space Agency which will support the extraction and analysis of lunar surface and subsurface samples as well as the acquisition of data from additional environmental sensors. The key elements of PROSPECT are the ProSEED drill and the ProSPA analytical laboratory. ProSEED will support the acquisition of cryogenic samples from depths up to 1 m and deliver them to the ProSPA instrument. ProSPA will receive and seal samples in miniaturized ovens, heat them, physically and chemically process the released volatiles, and analyze the obtained constituents via mass spectrometry using two types of spectrometers. Contextual information will be provided by cameras which will generate multi-spectral images of the drill working area and of acquired samples, and via temperature sensors and a permittivity sensor that are integrated in the drill rod. The package is designed for minimizing volatile loss from the sample between acquisition and analysis. Initially developed for a flight on the Russian Luna-27 mission, the payload package design was adapted for a more generic lander accommodation and will be flown on a lunar polar lander mission developed within the NASA Commercial Lunar Payload Services (CLPS) program. PROSPECT targets science and exploration in lunar areas that might harbor deposits of volatiles, and also supports the demonstration of In-Situ Resource Utilization (ISRU) techniques in the lunar environment. PROSPECT operations are designed to be automated to a significant degree but rely on operator monitoring during critical phases. Here, we report the PROSPECT flight design that will be built, tested, and qualified according to European space technology engineering standards before delivery to the lander provider for spacecraft integration. The package is currently in the hardware manufacturing and integration phase with a target delivery to the NASA-selected CLPS lander provider in 2025

Vernetzungen und Publikumskonstruktionen im Internet

Passoth J-H, Sutter T, Wehner J. Vernetzungen und Publikumskonstruktionen im Internet. In: Frank-Job B, Mehler A, Sutter T, eds. Die Dynamik sozialer und sprachlicher Netzwerke. Konzepte, Methoden und empirische Untersuchungen an Beispielen des WWW. Wiesbaden: Springer VS; 2013: 139-159

This time it’s different? Effects of the Eurovision Debate on young citizens and its consequence for EU democracy:Evidence from a quasi-experiment in 24 countries

For the very first time in EU history, the 2014 EP elections provided citizens with the opportunity to influence the nomination of the Commission President by casting a vote for the main Europartiesâ âlead candidatesâ. By subjecting the position of the Commission President to an open political contest, many experts have formulated the expectation that heightened political competition would strengthen the weak electoral connection between EU citizens and EU legislators, which some consider a root cause for the EUâs lack of public support. In particular, this contest was on display in the so-called âEurovision Debateâ, a televised debate between the main contenders for the Commission President broadcasted live across Europe. Drawing on a quasi-experimental study conducted in 24 EU countries, we find that debate exposure led to increased cognitive and political involvement and EU support among young citizens. Unfortunately, the debate has only reached a very small audience