Anreize und Motive für die Mitwirkung in Kirchenchören: Empirische Studie innerhalb der Ev.-Luth. Landeskirche Sachsens

Die Dissertation widmet sich der Frage, was Menschen motiviert, in evangelischen Kirchenchören mitzuwirken, wobei sich die Forschung auf die Sängerinnen und Sänger des Kirchenchorwerkes der Ev.-Luth. Landeskirche Sachsens fokussiert. Als erster Schritt wird anhand relevanter vorliegender Kenntnisse u. a. der Motivations-, Sozial-, Musik- und Religionspsychologie, der Soziologie und Musikpräferenzforschung ein wissenschaftliches Verständnis der Motivation für die Mitwirkung in Kirchenchören entwickelt, dieses mit dem theoretischen Wissen der Praxis von Kirchenchören in Beziehung gesetzt und ein Kategoriensystem potentieller Anreize bzw. Motive der Kirchenchorpraxis erarbeitet. Anschließend erfolgt die Überprüfung und Erweiterung der gewonnenen Erkenntnisse anhand zweier aufeinander aufbauender empirischer Studien: Einer qualitativen exploratorischen Studie anhand von Leitfadeninterviews, aus deren Ergebnissen sechs Hypothesen zur sozialen, musikalischen und religiösen Motivation, zur Erlebnisqualität in der Chorpraxis, zu Zweckzentrierung und Routineaspekten der Chormitwirkung und zur musikalischen bzw. religiösen Sozialisation der Sänger abgeleitet wurden sowie einer quantitative Studie in Form einer Online-Befragung. Die Stichprobengröße hierfür beträgt 544. Die Ergebnisse der Studien bestätigen im Wesentlichen die Aussagen der Hypothesen, die eine große Bedeutung von musikalischen und sozialen Anreizen der Kirchenchorpraxis, Differenzen der religiösen Motivation bei Mitgliedern für alle offener Chöre im Vergleich zu spezialisierten Chören, das überragende Potential für Flow-Erleben bei der Mitwirkung in Konzerten im Vergleich zu Proben, geselligen Veranstaltungen und Gottesdiensten sowie eine bereits in der Kindheit bzw. Jugend erfolgte religiöse und/ oder überdurchschnittlich musikalische Sozialisation der Chormitglieder postulieren. Als Fazit werden Anregungen für die praktische Kirchenchorarbeit abgeleitet und die Ergebnisse aus theologisch-liturgischer Perspektive reflektiert

Two Intermembrane Space Tim Complexes Interact with Different Domains of Tim23p during Its Import into Mitochondria

Tim23p (translocase of the inner membrane) is an essential import component located in the mitochondrial inner membrane. To determine how the Tim23 protein itself is transported into mitochondria, we used chemical cross-linking to identify proteins adjacent to Tim23p during its biogenesis. In the absence of an inner membrane potential, Tim23p is translocated across the mitochondrial outer membrane, but not inserted into the inner membrane. At this intermediate stage, we find that Tim23p forms cross-linked products with two distinct protein complexes of the intermembrane space, Tim8p–Tim13p and Tim9p–Tim10p. Tim9p and Tim10p cross-link to the COOH-terminal domain of the Tim23 protein, which carries all of the targeting signals for Tim23p. Therefore, our results suggest that the Tim9p–Tim10p complex plays a key role in Tim23p import. In contrast, Tim8p and Tim13p cross-link to the hydrophilic NH2-terminal segment of Tim23p, which does not carry essential import information and, thus, the role of Tim8p–Tim13p is unclear. Tim23p contains two matrix-facing, positively charged loops that are essential for its insertion into the inner membrane. The positive charges are not required for interaction with the Tim9p–Tim10p complex, but are essential for cross-linking of Tim23p to components of the inner membrane insertion machinery, including Tim54p, Tim22p, and Tim12p

Formation of cristae and crista junctions in mitochondria depends on antagonism between Fcj1 and Su e/g

Crista junctions (CJs) are important for mitochondrial organization and function, but the molecular basis of their formation and architecture is obscure. We have identified and characterized a mitochondrial membrane protein in yeast, Fcj1 (formation of CJ protein 1), which is specifically enriched in CJs. Cells lacking Fcj1 lack CJs, exhibit concentric stacks of inner membrane in the mitochondrial matrix, and show increased levels of F1FO–ATP synthase (F1FO) supercomplexes. Overexpression of Fcj1 leads to increased CJ formation, branching of cristae, enlargement of CJ diameter, and reduced levels of F1FO supercomplexes. Impairment of F1FO oligomer formation by deletion of its subunits e/g (Su e/g) causes CJ diameter enlargement and reduction of cristae tip numbers and promotes cristae branching. Fcj1 and Su e/g genetically interact. We propose a model in which the antagonism between Fcj1 and Su e/g locally modulates the F1FO oligomeric state, thereby controlling membrane curvature of cristae to generate CJs and cristae tips

Ethylene supports colonization of plant roots by the mutualistic fungus Piriformospora indica

The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica

The Tim54p–Tim22p Complex Mediates Insertion of Proteins into the Mitochondrial Inner Membrane

We have identified a new protein, Tim54p, located in the yeast mitochondrial inner membrane. Tim54p is an essential import component, required for the insertion of at least two polytopic proteins into the inner membrane, but not for the translocation of precursors into the matrix. Several observations suggest that Tim54p and Tim22p are part of a protein complex in the inner membrane distinct from the previously characterized Tim23p-Tim17p complex. First, multiple copies of the TIM22 gene, but not TIM23 or TIM17, suppress the growth defect of a tim54-1 temperature-sensitive mutant. Second, Tim22p can be coprecipitated with Tim54p from detergent-solubilized mitochondria, but Tim54p and Tim22p do not interact with either Tim23p or Tim17p. Finally, the tim54-1 mutation destabilizes the Tim22 protein, but not Tim23p or Tim17p. Our results support the idea that the mitochondrial inner membrane carries two independent import complexes: one required for the translocation of proteins across the inner membrane (Tim23p–Tim17p), and the other required for the insertion of proteins into the inner membrane (Tim54p–Tim22p)