Methylglyoxal — ein toxisches Fermentationsprodukt

Methylglyoxal (CH₃COCHO) is a toxic intermediate of the carbon metabolism. Its accumulation in the growth medium of microorganisms may be an important danger for many fermentation processes. In this paper data will be presented which show the physiological effect of this compound on the living cell, the enzymes responsible for the synthesis and the turnover of methylglyoxal including the environmental conditions necessary for the accumulation of lethal concentrations in the medium.     

Robuste schätzungen: Ein anwendungsorientierter Überblick

The paper offers an introductory survey of the area of robust estimation for applied statisticians, without demanding much mathematics. At first, the most important basic ideas of the robustness theory are explained using an example from the analysis of variance. Then the general reasons for and limits of the “robustification” of statistics are delineated. In particular, the various types of deviations from ideal models, such as gross errors, are discussed and their consequences are pointed out. The next part describes several simple robust estimators and their properties, ending with an outlook on robust estimators in linear models. As an appendix a number of frequent objections to and misunderstandings of robustness theory are discussed, refuted and clarified.     

Abbau und Umsetzung von lignifiziertem Pflanzenmaterial durch mikroskopische Bodenpilze

Zusammenfassung Es wird über eine Methode berichtet, an extrem dünnen Holzfolien die Abbauleistungen von Bodenpilzen zu messen.Aus einer Gesamtzahl von 280 geprüften Pilzarten wurden bei 27 mikroskopischen Pilzen mit hoher Aktivität Gewichtsabnahme und Reißfestigkeit von Ahornholz bestimmt.An Weizenstroh wurde mit einer Auswahl leistungsfähiger Pilze die Verminderung des Lignin- und Cellulosegehalts untersucht.Nach 120 Bebrütungstagen lag die Abnahme für Lignin zwischen 31 und 52%, für Cellulose zwischen 33 und 66%.Von den untersuchten Pilzen zeichneten sich Mammaria echinobotryoides, Hormiactis candida und Chaetomium piluliferum durch eine besonders starke Phenolproduktion aus.Die für alle geprüften Pilze mehr oder weniger typische Phenolproduktion stand in enger Beziehung zur Bildung von Huminstoffen, die bei der Rotte des Strohes auftraten.

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Decomposition and transformation of lignified plant material by microscopic soil fungi

Summary The use of ultra-thin foils prepared from maple wood for measuring the wood-destroying capacity of soil fungi is described.Data are given on the reduction of dry-weight and tensile strength by the action of 27 highly active species from a total number of 280 microfungi.The decrease in lignin and cellulose content of wheat straw was studied with a selected number of fungi.The percentage reduction after an incubation period of 120 days was found to be between 31 and 52% for lignin, 33 and 66% for cellulose content respectively.A remarkable production of phenols was found in liquid cultures of Mammaria echinobotryoides, Hormiactis candida and Chaetomium piluliferum.The phenol production was more or less typical for all the examined fungi. There was a close relationship between the phenol metabolism and dark humic acid-like substances occurring during the decomposition of straw.