Nonenzymic browning XV. Effect of unsaturation on browning reactions of oxidized lipids with protein

Summary The amount of pigments produced by interaction of oxidized lipids with albumin and the intensity of coloration increase with increasing degree of unsaturation of the lipid fraction.

---

Nichtenzymatische Bräunung XV. Einfluß der Ungesättigkeit auf die Bräunungsreaktionen oxydierter Lipide mit Protein

Zusammenfassung Die Menge der braunen Produkte der Wechselwirkung zwischen oxydierten Lipiden und Albumin und die Intensität der Verfärbung nehmen mit der zunehmenden Ungesättigkeitsstufe des Lipidanteils zu.

     

An in vivo detection system for transient and low‐abundant protein interactions and their kinetics in budding yeast

Methylation tracking (M‐Track) is a protein‐proximity assay in Saccharomyces cerevisiae, allowing the detection of transient protein–protein interactions in living cells. The bait protein is fused to a histone lysine methyl transferase and the prey protein to a methylation acceptor peptide derived from histone 3. Upon interaction, the histone 3 fragment is stably methylated on lysine 9 and can be detected by methylation‐specific antibodies. Since methylation marking is irreversible in budding yeast and only takes place in living cells, the occurrence of artifacts during cell lysate preparation is greatly reduced, leading to a more accurate representation of native interactions. So far, this method has been limited to highly abundant or overexpressed proteins. However, many proteins of interest are low‐abundant, and overexpression of proteins may interfere with their function, leading to an artificial situation. Here we report the generation of a toolbox including a novel cleavage‐enrichment system for the analysis of very low‐abundant proteins at their native expression levels. In addition, we developed a system for the parallel analysis of two prey proteins in a single cell, as well as an inducible methylation system. The inducible system allows precise control over the time during which the interaction is detected and can be used to determine interaction kinetics. Furthermore, we generated a set of constructs facilitating the cloning‐free genomic tagging of proteins at their endogenous locus by homologous recombination, and their expression from centromeric plasmids. GenBank submissions: pCK900; KM407502, pCK901; KM407503, pCK902; KM407504, pCK903; KM407505, pCK904; KM407506, pCK905; KM407507, pCK906; KM407508, pCK907; KM407509, pCK908; KM407510, pCK909; KM407511, pCK910; KM407512, pCK911; KM407513. © 2015 The Authors. Yeast published by John Wiley & Sons Ltd.     

Nonenzymic browning. IX. Correlation of autoxidation and browning reactions in lipid-protein mixtures

Summary Polyunsaturated esters prepared from cod fish oil were rapidly oxidized in mixtures with casein but the peroxides formed as primary reaction products were rapidly destroyed. The carbonylic oxidation products reacting with benzidine or with 2-thiobarbituric acid behaved in the same manner. On the contrary, the browning proceeded slowly and the course was independent of changes of peroxides and carbonyl derivatives, so that some colourless intermediary products were obviously first formed which were then transformed into brown pigments. After reduction of peroxides with potassium iodide the extent of browning was much reduced but the reaction of remaining benzidine-active substances correlated well with browning reactions in mixture with protein. Most of the browning in lipid-protein mixtures was due to the reactions of peroxides, probably through some decomposition products.

---

Nichtenzymatische Bräunung. IX. Korrelation zwischen Autoxydation und Bräunungsreaktionen in Lipid-Protein-Mischungen

Zusammenfassung Mehrfach ungesättigte Ester von Dorschleberöl wurden im Gemisch mit Casein schnell oxydiert, aber die als primäre Reaktionsprodukte gebildeten Peroxide wurden schnell zersetzt. Die carbonylhaltigen Oxydationsprodukte, die mit Benzidin oder mit 2-Thiobarbitursäure reagierten, verhielten sich auf derselben Weise. Zum Unterschied von den Oxydationsreaktionen verlief die Bräunung nur langsam und war von den Veränderungen der Peroxide und Carbonylderivate unabhängig. Es wurden zuerst farblose intermediäre Produkte gebildet, die dann in braune Stoffe umgewandelt wurden. Nach der Reduktion der Peroxide mit Kaliumjodid wurde die Bräunungsintensität erheblich erniedrigt, jedoch war die Reaktion von den zurückgebliebenen benzidinaktiven Stoffen in einer guten Korrelation mit der Geschwindigkeit der Bräunungsreaktionen im Gemisch mit Protein. Die Bräunung in Lipid-Protein-Gemischen ist also meistens durch die Reaktion von Peroxiden, weniger durch die Reaktion der Carbonylderivate, verursacht. Die Peroxide reagieren wahrscheinlich über einige ihrer Zersetzungsprodukte.

     

Modelling of heat transfer in hot strip mill runout table cooling

The need for accurate prediction and control of cooling profiles of steel strips on runout tables has led to the development of a mathematical model that is able to predict coiler temperatures under any given condition with an accuracy of ± 14 °C as well as calculating the entire temperature profile of a steel strip with sufficient accuracy. Comparisons with online strip temperature data at various locations of the runout table, which were obtained by a new experimental procedure, show that the effect of single cooling headers on the thermal response of a steel strip can be predicted. The model takes into account all relevant thermodynamic effects by means of a statistical approach. Heat transfer to the environment, steel thermophysical properties and phase transformation are modelled using B‐splines. Model adaptation is realised by fitting calculated and measured coiler temperatures of approximately 40000 strips with a least square method in order to gain optimal base values for the B‐spline functions. During model development special attention was paid to the model's capability of being re‐adjustable to a large variety of conditions as well as its local behaviour. Therefore, concepts like temperature‐dependent heat transfer coefficients, which are applicable only to one specific plant, have been avoided in favour of a more generalised formulation of the model that helps to gain insight into the physics of the processes involved, i.e. heat transfer of subcooled jet impingement boiling and film boiling. It was found that both cooling water and steel surface temperature have a large influence on heat transfer whereas the influence of strip speed can be neglected.     

Bestimmung der Zerst?rung von Trypsininhibitoren w?hrend der Sojabohnenentbitterung

Zusammenfassung Die Untersuchung der Proteolyse durch Trypsin bei unterschiedlichen Konzentrationen von Sojaextrakten ermöglicht eine genauere Bestimmung der Antitrypsin Aktivität als die üblichen Methoden. Im Laufe der Entbitterung durch Wasserdampf werden Trypsininhibitoren fast völlig inaktiviert; beim trockenen Erhitzen ist jedoch die Inaktivierung sehr langsam. Zwischen den Resultaten der Bestimmung der Antitrypsin-und der Uresse-Aktivität ist die Korrelation gut, wenn die Inaktivierung in nassem Millieu verläuft, in trockenem Material wird die Urease beim Erhitzen wesentlich schneller als die Trypsininhibitoren inaktiviert.     

Exploratory Notes on the Geography of Black Gay Leisure Spaces in Bloemfontein,South Africa

Gay leisure space development has of late been an important area of investigation in geography. Generally, these investigations have primarily concerned white gay men in Western countries. Most of these debates have not been considered in the developing world context, particularly in Africa. This investigation explores the leisure geography of black gay men in the city of Bloemfontein. It is shown that differences in race and class positions explain a gay leisure geography which stands totally separate from that of white gay men. The investigation argues that differences in class position, linked to race, explain these separate geographies. However, it is also revealed that the black gay men of this investigation do not see exclusively gay leisure spaces as desirable and would rather seek leisure spaces that are inclusive of different sexual orientations.