92 research outputs found
Oxygen control of nif gene expression in Klebsiella pneumoniae depends on NifL reduction at the cytoplasmic membrane by electrons derived from the reduced quinone pool
No full textIn Klebsiella pneumoniae , the flavoprotein, NifL regulates NifA mediated transcriptional activation of the N-2-fixation (nif) genes in response to molecular O-2 and ammonium. We investigated the influence of membrane-bound oxidoreductases on nif -regulation by biochemical analysis of purified NifL and by monitoring NifA-mediated expression of nifH'-'lacZ reporter fusions in different mutant backgrounds. NifL-bound FAD-cofactor was reduced by NADH only in the presence of a redox-mediator or inside-out vesicles derived from anaerobically grown K. pneumoniae cells, indicating that in vivo NifL is reduced by electrons derived from membrane-bound oxidoreductases of the anaerobic respiratory chain. This mechanism is further supported by three lines of evidence: First, K. pneumoniae strains carrying null mutations of fdnG or nuoCD showed significantly reduced nif- induction under derepressing conditions, indicating that NifL inhibition of NifA was not relieved in the absence of formate dehydrogenase-N or NADH:ubiquinone oxidoreductase. The same effect was observed in a heterologous Escherichia coli system carrying a ndh null allele (coding for NADH dehydrogenaseII). Second, studying nif -induction in K. pneumoniae revealed that during anaerobic growth in glycerol, under nitrogen-limitation, the presence of the terminal electron acceptor nitrate resulted in a significant decrease of nif-induction. The final line of evidence is that reduced quinone derivatives, dimethylnaphthoquinol and menadiol, are able to transfer electrons to the FAD-moiety of purified NifL. On the basis of these data, we postulate that under anaerobic and nitrogen-limited conditions, NifL inhibition of NifA activity is relieved by reduction of the FAD-cofactor by electrons derived from the reduced quinone pool, generated by anaerobic respiration, that favours membrane association of NifL. We further hypothesize that the quinol/quinone ratio is important for providing the signal to NifL
Diasporas and democratization in the post-communist world
No full textIf diaspora communities are socialized with democratic values in Western societies, they could be expected to be sympathetic to the democratization of their home countries. However, there is a high degree of variation in their behavior. Contrary to the predominant understanding in the literature that diasporas act in exclusively nationalist ways, this article argues that they do engage with the democratization of their home countries. Various challenges to the sovereignty of their homelands explain whether diasporas involve with procedural or liberal aspects of democratization. Drawing evidence from the activities of the Ukrainian, Serbian, Albanian and Armenian diasporas after the end of communism, I argue that unless diasporas are linked to home countries that enjoy both international legal and domestic sovereignty, they will involve only with procedural aspects of democratization. Diasporas filter international pressure to democratize post-communist societies by utilizing democratic procedures to advance unresolved nationalist goals
“Faithfully loyal to Your Imperial Highness...” Letters of bishop Grigoriy (Grabbe) to grand prince Vladimir Kirillovich (1971–1991)
No full textThis article makes public letters of Bishop Grigoriy (Grabbe; prior to 1979, protopresbyter Georgiy). The author of these letters was for several decades secretary of the Synod of Bishops of the Russian Orthodox Church Abroad and Ruler of the affairs of the Synodal offi ce of the Russian Orthodox Church Abroad. In the 1960s — early 1980s, he had a great power that sometimes exceeded the power of the Chairman of the Synod of bishops, Metropolitan Filaret (Voznesensky). The recipient of the letters is Grand Prince Kirill Vladimirovich Romanov. Although in 1939, the Russian Church Abroad actually recognised this person as the spiritual leader of the future free Russia, in the post-war years the attitude to him deteriorated. The correspondence was conducted against the background of protests by representatives of the house of the Romanovs, who did not agree with Vladimir Kirillovich’s claims to the throne. The author of the letters, being a supporter of Vladimir Kirillovich, tried to support him. The correspondence is also interesting because it refl ects important events in the life of the Russian Orthodox Church Abroad in those years. This is the preparation of the canonisation of new martyrs and confessors of Russia, the scandalous marriage that Revd. Grabbe performed on M. Golenevsky, calling him Tsarevich Alexei, and internal confl icts within the Russian Church Abroad. The correspondence refl ected Bishop Grigoriy’s attitude to the changes in the home country in the late 1980s and early 1990s, to Vladimir Kirillovich’s trip to the Soviet Union and his meeting with Patriarch Alexy II
Riches, Poverty, and the Faithful: Perspectives on Wealth in the Second Temple Period and the Apocalypse of John
No full textThe present study considers the degree to which John’s portrayal of the faithful Christian community in the Apocalypse is informed by Jewish apocalyptic traditions related to wealth in the Second Temple period. Previous studies have attributed the author’s radical stance against wealth and economic participation to an ad hoc response against the idolatry and social injustices of the Roman Empire and imperial cults. This thesis argues that there is reasonable evidence to suggest that the author may have already been predisposed to reject affluence as a feature of the present age for the ideal faithful community based on received tradition.
The study begins by delineating the problem in a critical review of how scholars have attempted to deal with this language through either the social world of Roman Asia Minor or the author’s use of the biblical prophets. This discussion demonstrates the need to take a tradition-historical approach that includes an examination of Jewish apocalyptic traditions preserved among the Dead Sea Scrolls as well as other Jewish literature not found at Qumran that demonstrate a decided concern over wealth. These Second Temple texts are then examined collectively against the language of wealth and poverty in selected passages of the Apocalypse. The evidence reveals an emphasis on the part of John on the irreversible, eschatological consequences of ethical behaviour directly related to wealth based on a certain cosmological and theological understanding, an emphasis that has close analogies in some Second Temple literature.
The study concludes that traditions preserved in the Epistle of Enoch and later Enochic texts have played a formative role in shaping the author’s theological perspective concerning material blessing for the faithful in the present age and the world through which he legitimised the radical stance he imposed on his readers/hearers
“I remain sincere friend of the Russian Orthodox Church Abroad”. Letters from hieromonk Vasily (Rodzianko) to protopresbyter Georgy Grabbe
No full textThis article makes public the letters of Revd. Vladimir Rodzianko (Hieromonk Vasily) to Protopresbyter Georgy Grabbe. Both the sender and the addressee are wellknown. The former is the future bishop and a long-term prsenter of Orthodox programmes on BBC Radio. The former also became a bishop, and for many years was the secretary of the Synod of Bishops of the Russian Church Abroad having a great infl uence on its policy. The letters were written in the early 1979 in the moment of great changes in the life of their author. The fi rst letter was prepared when he was Protopriest Vladimir, the second soon after his becoming a monk as Hieromonk Vasily. The reason for the letters were the attacks of the administration of the Russian Church Abroad against Moscow Patriarchate as well as the idea, popular in the Russian Orthodox Church, that there is no holy grace at all in any communities not belonging to the Orthodox Church. This idea was put forward by Protopresbyter G. Grabbe in the article Acribeia and Oeconomy. This approach was aggravated by the fact that the administration of the Russian Church Abroad regarded as apostate the clergy of Moscow Patriarchate. The consequence was an idea about their gracelessness. Hieromonk Vasily (Rodzianko) thought that this was erroneous and dangerous. Using certain historical evidence and an opinion of St. Ioann (Maksimovich), he claimed that the Orthodox gaith and the Eucharist are supreme over the jurisdictional controversies and that the temporary discord does not aff ect grace. The letters contain interesting facts as to relations between the Russian Church Abroad and the Serbian Church in the 1920s — 1940s, describe little-known details between the Russian Church Abroad and other branches of Russian church in exile
Regulation der Stickstoffixierung in <i>Klebsiella pneumoniae</i>: die Rolle von Fnr in der Sauerstoffsignaltransduktion
No full textIn Klebsiella pneumoniae wird die Aktivität des Transkriptionsaktivators NifA durch NifL in Abhängigkeit von gebundenem Stickstoff und molekularem Sauerstoff geregelt. NifL, ein Flavoprotein, das redox-sensitiv ist, scheint, das Sauerstoffsignal über eine Konformationsänderung auf NifA zu übertragen. Kürzlich konnten wir zeigen, dass in einer K. pneumoniae fnr null Mutante NifL das Signal für Sauerstofflimitierung nicht erhält, was zu einer inhibitorischen Konformation des Proteins führt. Dies bedeutet, dass Fnr, indirekt oder direkt, in diese Signalübertragung involviert ist. Wir nehmen an, dass Fnr als primärer Sauerstoffsensor Gene der anaeroben Atmungskette kontrolliert, die wiederum Elektronen für die Reduktion des FAD-Cofaktors in NifL zur Verfügung stellen. Interessanterweise findet sich in einer unter Sauerstoff- und Stickstofflimitierung gewachsenen fnr Mutante bis zu 95% des NifL Proteins im Cytoplasma, während im Wildtyp 55% des Regulators in der Membranfraktion nachgewiesen werden können. In der Mutante wird der räumliche Abstand zwischen NifL und NifA, der letztlich NifA die Enhancer Funktion in der nif Gene Transkription ermöglicht, verhindert.Unter Sauerstofflimitation ist NifL also hauptsächlich an der Membran lokalisiert, wobei sein FAD-Cofaktor reduziert wird und NifL so in seiner nicht-inhibitorischen Konformation verweilt. Um diese Reduktion nachzuweisen, untersuchten wir die Übertragung von Elektronen von reduzierten invertierten Membranvesikeln bzw. Quinolen auf den FAD-Cofaktor von NifL. Wir konnten eindeutig zeigen, dass sowohl Vesikel als auch Quinole in der Lage sind, Elektronen von NADH auf NifL zu übertragen. Dies unterstützt die Theorie der Reduktion von NifL mit Elektronen aus Quinol-Poolen, die durch die anaerobe Atmungskette generiert werden, an der Cytoplasmamembran. Unterstützt wird diese These durch NifA-abhängige Expressionsstudien mit K. pneumoniae Stämmen, die Null-Mutationen in Oxidoreduktasen, z.B. NADH-Oxidoreduktase, der anaeroben Atmung aufweisen. In diesen Stämmen sind die Expressionslevel nahezu identisch mit denen des Wildtyp Stammes unter aeroben Bedingungen.Wir schlagen deshalb ein Model vor, in dem NifL an der cytoplasmatischen Membran durch Elektronen aus dem Quinol-Pool reduziert wird. Gespeist wird dieser Pool mit Elektronen der anaeroben Atmungskette.In Klebsiella pneumoniae transcriptional activity of NifA is modulated by NifL in response to combined nitrogen or molecular oxygen. NifL a flavoprotein, which is redox-sensitive, apparently mediates the oxygen signal towards NifA through a conformational switch. We recently showed that in a fnr null mutational K. pneumoniae strain NifL does not receive the signal for anaerobiosis, resulting in an inhibitory conformation of NifL. Indicating, Fnr seems to be involved in the signal transduction pathway, directly or indirectly. We proposed that fnr-dependent genes, the products of which function to relieve NifL inhibition by reducing the FAD moiety of NifL, resulting in a non-inhibitory conformation. We further hypothized that members of the anaerobic electron transport chain could be involved in this signal transduction. Interestingly, in a anerobic and nitrogen limited K. pneumoniae fnr-null mutant 95% of NifL protein is located in the cytoplasm, contrarely to the conditions in the wild type, where 55% of NifL is found in the membrane fraction. In the mutant strain, the spatial gap between NifL and NifA, which allows NifA to enhance transcription of the nif-genes, is abolished.In K. pneumoniae wild type strains under oxygen limitation NifL is mainly located at the cytoplasmic membrane and recieves electrons leading to a reduced FAD cofactor, which allows NifL to retain the non-inhibitory conformation. Consequently, we started experiments to reduce oxidized NifL using reduced inside out vesicles and quinone derivatives in the presence of NADH. We clearly demonstrated that both membrane vesicles and quinone derivatives are highly potential in electron transduction from NADH towards NifL. Indicating that electrons from the anaerobic respiratory chain, which are mainly found in the quinone pools in the cytoplasmic membrane are used to reduce the FAD moiety of NifL resulting in a non-inhibitory conformation of the protein. These findings were confirmed by K. pneumoniae strains carrying null mutations of anaerobic reductases, for example NADH-oxidoreductase. These mutant strains failed to relieved NifL inhibition or showed reduced nifH-lacZ transcription levels in the appropriate genetic backgrounds.We favor a model in which NifL is membrane associated under anaerobic and nitrogen limited conditions and recieves electrons from the anaerobic respiratory chain, especially from the reduced quinone pools, resulting in a non-inhibitory conformation
In search of Xerxes: images of the Persian king
No full textThe figure of Xerxes, the Persian king who invaded Greece in 480 BC, is known to us primarily through Greek sources and the western inheritors of the Greek tradition. Little Persian evidence from Xerxes' reign survives and our perceptions are, therefore, informed by the image of the king constructed by his enemies whose experience of the Persian Wars was a key moment in their own selfdefinition. As a result, Xerxes is perceived as the antithesis of all that the Greeks represented: the barbarian despol, a figure to be both feared and mocked. This leads to the marginalisation - both literal and symbolic - of the king even in sources where we might expect him to play a key role in the Persian Wars narrative. My thesis examines the creation and perpetuation of a cultural repertoire within which Xerxes is othered and deprived of a subjective voice. After an examination of the scant Persian evidence for Xerxes' rcign, it considers the Greek sources of the fifth and fourth centuries BC, beginning with Acschylus and Herodotus and moving into di scussion of the diverse presentations of Timotheus, Ctesias and the orators and philosophers of fourth-century Athens. Later Greek sources - primarily Diodorus and Josephus - are then studied, before an analysis of the Xerxes-traditions in Roman thought. Finally the figure of Xerxes in Greek writing of the second sophistic period is considered
The Soft Engine for Economic Growth in a Long-Time:The Economic Development Power, Conversion and Conservation for economic Energy
No full textBased on the theories of Development Power([18]-[20]) and Partial Distribution([21]-[24]), and combining with the actual economic development, this paper discusses the main ways how the Development Power (DP) is accumulated or released, establishes the analytic models of DP and the model of relation between DP and productivity; classifies economic development into the three states in energy¡ªthe state of normal energy, strong energy and super energy; gives the method of calculating the critical time of strong energy and super energy and the approach to describe the evolving process of these three states; puts forward the laws of conversion and conservation between mass and energy in economic developing. According to that DP is accumulated and released one after another, this paper points out, a sign that accumulation of DP is completed is the most of economic factors are in order, and the sign that release of DP is completed is the most of economic factors are in chaos, and also gives the ways to calculate the most possible time that the DP starts accumulating or releasing. Finally, the author make a comprehensive empirical analysis on all of results in this paper by means of the US GDP data from 1940 to 2003, the outcomes are satisfied. The conclusions in this paper make clear that the economic Development Power, namely economic development energy, is the engine for the economic growth.Development Power (DP), Partial Distribution, economic growth, energy states of economic development, conversion and conservation on economic energy, analytic model
"What does the case of Slovakia tell us about the EU’s Active Leverage?"
No full text[From the introduction]. This short paper seeks to reflect on the experience of Slovakia and highlights what that particular case has taught us about the active leverage of the EU. I recognize that unpicking causation between domestic and European arenas is fraught with methodological difficulties (Haverland, 2006). Unlike our colleagues from chemistry, as political scientists we are not afforded the luxury to isolate and remove individual ingredients and then re-run experiments to see if the results change, hence identifying chains of causation is extremely difficult and tends to lead to conclusions, which are vague, hedged and less than robust. Bearing that caveat in mind, however, I venture a few arguments based on a close observation of the Slovak case. Firstly, building on the helpful distinction between political2 conditionality and acquis conditionality, I suggest that the Slovak case demonstrates the power of acquis conditionality, but the limits of the ‘transformative power’ (Grabbe, 2006) of political conditionality. Indeed, acquis conditionality may be more influential in cases where political conditionality is perceived to have had an influence. Secondly, the EU has very little impact on domestic party politics beyond influencing the choice of coalition partners, but even here the impact of the EU is probably exaggerated. Thirdly, the power of the acquis conditionality varies depending on the clarity, consistency and ascribed salience of such laws
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