Regulation of mitochondrial energy generation in health and disease

AbstractIn mammalian cytochrome c oxidase (COX) three of the ten nuclear coded subunits (VIa, VIIa, VIII) occur in tissue-specific isoforms. The isoform distribution, however, varies in liver and heart of different species. Subunit VIII is different in liver and heart of bovine, dog, rat and chicken, but identical in human (liver-type) on one hand, and sheep, rabbit and rainbow trout (heart-type) on the other hand, as determined by N-terminal sequencing. Two moles of trinitrophenyl-ATP bind to monomeric COX from bovine heart and one to COX from bovine liver with dissociation equilibrium constant (Kd) values of about 3 μM. One binding site at the heart enzyme is blocked by aa monoclonal antibody to subunit VIa-H. ATP (and/or ADP) interact with COX at two or three high-affinity binding sites, as shown by titration of the spectral changes of COX. Isolated COX from bovine heart was reconstituted with variable intraliposomal ATP/ADP ratios. By measuring the RCR (respiratory control ratio) and RCRVal (related to the valinomycin-respiration), which is a direct measure of the H+e−-stoichiometry (Wilson and Prochaska, Arch. Biochem. Biophys. 282 (1990) 413–420), almost complete inhibition of the proton pump activity of COX by high intraliposomal ATP concentrations was found. The vectorial uptake of protons for the formation of water, however, appears to be unaffected by nucleotides. This regulatory mechanism is assumed to have physiological significance for thermogenesis in muscle at rest. COX of fibroblasts from patients suffering from Leigh's syndrome, which is associated with a decreased COX activity, are suggested to have an incompletely assembled enzyme complex. This suggestion is further corroborated by the higher temperature-sensitivity of the enzyme when compared with COX from normal control fibroblasts. Defective regulation of COX via nuclear coded subunits is also proposed to cause mitochondrial diseases

The noise-lovers: cultures of speech and sound in second-century Rome

This chapter provides an examination of an ideal of the ‘deliberate speaker’, who aims to reflect time, thought, and study in his speech. In the Roman Empire, words became a vital tool for creating and defending in-groups, and orators and authors in both Latin and Greek alleged, by contrast, that their enemies produced babbling noise rather than articulate speech. In this chapter, the ideal of the deliberate speaker is explored through the works of two very different contemporaries: the African-born Roman orator Fronto and the Syrian Christian apologist Tatian. Despite moving in very different circles, Fronto and Tatian both express their identity and authority through an expertise in words, in strikingly similar ways. The chapter ends with a call for scholars of the Roman Empire to create categories of analysis that move across different cultural and linguistic groups. If we do not, we risk merely replicating the parochialism and insularity of our sources.Accepted manuscrip

The Impact of an Offshore Wind Farm on a Power Grid

Due to increasing power demands and growing importance of sustainability, more and morewind power is being built and connected to existing power systems. While wind power isboth renewable and cost-effective, it is important to note that due to its variable nature, itcan negatively impact the stability of a power system. The aim of this project is to analyze apower grid with the addition of a large wind farm to study how it affects the power grid.This is simulated with a simplified model of a part of the power grid around Skellefte River,Sweden. Power generation and consumption in the model is based on data from the realworld. The conclusions of the project were that when dimensioning a power grid with alarge share of wind power, the variability of wind power needs to be taken intoconsideration. Otherwise, as the results of this project show, the stability of the power gridcan be reduced.På grund av att samhället efterfrågar mer elektricitet och samtidigt ställer högre krav påhållbarhet byggs i nuläget allt mer vindkraft som ansluts till existerande kraftsystem. Medanvindkraft både är förnybart och kostnadseffektivt är det viktigt att påpeka att vindkraftensvariabilitet kan påverka stabiliteten i ett kraftsystem negativt. Syftet med detta projekt äratt analysera hur ett kraftsystem påverkas av att en stor vindkraftsfarm läggs till i systemet.Detta simuleras med en simplifierad modell av en del av kraftsystemet runt Skellefteälven,Sverige. Produktions- och konsumptionsdata i modellen är baserad på data från den riktigavärlden. Projektets slutsatser blev att när ett kraftsystem med stor del vindkraftdimensioneras måste vindkraftens variabilitet beaktas. Annars, som resultaten i dettaprojekt visar, kan stabiliteten i kraftsystemet försämras.Kandidatexjobb i elektroteknik 2023, KTH, Stockhol

Darstellung von Zellproliferationsmustern während der Gehirnentwicklung im Huhn

In dieser Arbeit werden die Proliferationszonen des gesamten Gehirns während der Entwicklung des Huhns dargestellt. Untersucht wurden Hühnerembryonen vom 5. bis zum 19. Entwicklungstag, sowie adulte Hühner mithilfe der ggH4-RNA-in-situ-Hybridisierung. Des Weiteren wurde die Zellzyklusdauer embryonaler Hühnerfibroblasten mittels Durchflusszytometrie nach Synchronisation mit Thymidin untersucht. Mithilfe dieser Methoden konnten folgende Ergebnisse erzielt werden: Die Zellzyklusdauer der 6-Tage-alten, embryonalen Hühnerfibroblasten beträgt ca. 10 h. Im wachsenden Gehirn der Embryonen gibt es ein entwicklungsspezifisches Muster der Proliferation mit hohen Proliferationsraten neben Bereichen mit geringer oder gar keiner Proliferation. So sind beispielsweise in der Zona subventricularis des Telencephalons während der gesamten Embryonalentwicklung starke, im Hippocampus hingegen keine Proliferationssignale zu beobachten. Der Lobus opticus ist mit seinem 15-schichtigen Aufbau ein wichtiges Modell zur Untersuchung komplexer neuronaler Strukturen. Auf die Darstellung des Lobus opticus wird in dieser Arbeit besonders eingegangen. Die im, histologisch dem Menschen sehr ähnlich aufgebauten, Cerebellum beobachteten Proliferationszonen korrelieren mit den bekannten Stammzelllokalisationen. Im adulten Huhn sind noch distinkte Proliferationssignale, vor allem in der Zona subventricularis, im Lobus opticus und im Cerebellum vorhanden