Die Bemessung für Querkraft erfolgt heute nach einheitlichen Modellvorstellungen; die Grundlage hierfür wurde vor über 100 Jahren gelegt und ab ca. 1960 durch die Arbeiten auf dem Gebiet der Plastizitätstheorie theoretisch untermauert. In neueren Untersuchungen wurden die Modelle erweitert, wobei die Verträglichkeit der Verformungen und die Bestimmung der effektiven Betondruckfestigkeit im Vordergrund standen. Der vorliegende Beitrag gibt einen Überblick über diese Entwicklungen und zeigt auf, wie die Modelle für die Bemessung und konstruktive Durchbildung verwendet werden können.

The aim of the project EUROFAN (European Functional Analysis Network) is to elucidate the function of unknown genes of the yeast Saccharomyces cerevisiae at a large scale. Functional analysis is based on general and specific tests with yeast deletion strains. A prerequisite for these studies is a profound knowledge of the biochemistry and cell biology of the corresponding wild‐type strain FY1679. As a contribution from our laboratory we present here a systematic lipid analysis of the major organelles isolated from FY1679 grown in the presence of different carbon sources. Phospholipid, sterol and fatty acid composition are characteristic for each organelle. Moreover, growth of the yeast on glucose, ethanol or lactate causes in some cases marked changes of the organelle lipid pattern. As the most prominent example, cultivation of the yeast on non‐fermentable carbon sources results in an increase of mitochondrial cardiolipin. As another example, the ratio of unsaturated to saturated fatty acids is enhanced in cells grown on ethanol or lactate as compared to glucose. Thus, the lipid composition of yeast subcellular membranes reflects in a significant way the nutrient conditions caused by variation of the carbon source. Copyright © 1999 John Wiley & Sons, Ltd.

Addition of 0.1% of nonionic surface-active Tween 80 to a medium optimized for pectolytic enzyme production of Aspergillus niger increased the amount of enzymes excreted by 70%. In the presence of Tween 80 the amount of sterol esters and triacylglycerols was increased. During the course of cultivation the amounts of precursors for ergosterol biosynthesis diminished with an increase of ergosterol. A. niger incorporated cholesterol from the medium, partly converting it to cholesterol esters. Sterol esters were formed only with selected fatty acids. Oleic acid, the hydrophobic part of Tween 80, was mainly incorporated in phospholipids and glycolipids.

Sterol and fatty acid composition were combined for comparison of five industrially important Aspergillus species. Quantitative amounts of individual fatty acids, especially unsaturated ones, and the composition of sterols showed the differences among fungi examined. Besides ergosterol, six other sterols were present in detectable amounts in fungal mycelia. The most outstanding were the differences in the amounts of linolenic acid, ergosterol, and lanosterol, as well as in a sterol with M+376 identified as ergosterol peroxide.

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