Dissipative metabolic patterns respond during neutrophil transmembrane signaling

Self-organization is a common theme in biology. One mechanism of self-organization is the creation of chemical patterns by the diffusion of chemical reactants and their nonlinear interactions. We have recently observed sustained unidirectional traveling chemical redox [NAD(P)H − NAD(P)+] waves within living polarized neutrophils. The present study shows that an intracellular metabolic wave responds to formyl peptide receptor agonists, but not antagonists, by splitting into two waves traveling in opposite directions along a cell's long axis. Similar effects were noted with other neutrophil-activating substances. Moreover, when cells were exposed to an N-formyl-methionyl-leucyl-phenylalanine (FMLP) gradient whose source was perpendicular to the cell's long axis, cell metabolism was locally perturbed with reorientation of the pattern in a direction perpendicular to the initial cellular axis. Thus, extracellular activating signals and the signals' spatial cues are translated into distinct intracellular dissipative structures.

Dynamics of Fos-Jun-NFAT1 complexes

Transcription initiation in eukaryotes is controlled by nucleoprotein complexes formed through cooperative interactions among multiple transcription regulatory proteins. These complexes may be assembled via stochastic collisions or defined pathways. We investigated the dynamics of Fos-Jun-NFAT1 complexes by using a multicolor fluorescence resonance energy transfer assay. Fos-Jun heterodimers can bind to AP-1 sites in two opposite orientations, only one of which is populated in mature Fos-Jun-NFAT1 complexes. We studied the reversal of Fos-Jun binding orientation in response to NFAT1 by measuring the efficiencies of energy transfer from donor fluorophores linked to opposite ends of an oligonucleotide to an acceptor fluorophore linked to one subunit of the heterodimer. The reorientation of Fos-Jun by NFAT1 was not inhibited by competitor oligonucleotides or heterodimers. The rate of Fos-Jun reorientation was faster than the rate of heterodimer dissociation at some binding sites. The facilitated reorientation of Fos-Jun heterodimers therefore can enhance the efficiency of Fos-Jun-NFAT1 complex formation. We also examined the influence of the preferred orientation of Fos-Jun binding on the stability and transcriptional activity of Fos-Jun-NFAT1 complexes. Complexes formed at sites where Fos-Jun favored the same binding orientation in the presence and absence of NFAT1 exhibited an 8-fold slower dissociation rate than complexes formed at sites where Fos-Jun favored the opposite binding orientation. Fos-Jun-NFAT1 complexes also exhibited greater transcription activation at promoter elements that favored the same orientation of Fos-Jun binding in the presence and absence of NFAT1. Thus, the orientation of heterodimer binding can influence both the dynamics and promoter selectivity of multiprotein transcription regulatory complexes.

Arg-302 facilitates deprotonation of Glu-325 in the transport mechanism of the lactose permease from Escherichia coli

A mechanistic model for lactose/H+ symport via the lactose permease of Escherichia coli proposed recently indicates that the permease must be protonated to bind ligand with high affinity. Moreover, in the ground state, the symported H+ is shared between His-322 (helix X) and Glu-269 (helix VIII), whereas Glu-325 (helix X) is charge-paired with Arg-302 (helix IX). Substrate binding at the outer surface induces a conformational change that leads to transfer of the H+ to Glu-325 and reorientation of the binding site to the inner surface. After release of the substrate, Glu-325 is deprotonated on the inside because of rejuxtapositioning with Arg-302. To test the role of Arg-302 in the mechanism, the catalytic properties of mutants Arg-302→Ala and Arg-302→Ser were studied. Both mutants are severely defective in active lactose transport, as well as in efflux or influx down a concentration gradient, translocation modes that involve net H+ movement. In marked contrast, the mutants catalyze equilibrium exchange of lactose and bind ligand with high affinity. These characteristics are remarkably analogous to those of permease mutants with neutral replacements for Glu-325, a residue that plays a direct role in H+ translocation. These observations lend strong support for the argument that Arg-302 interacts with Glu-325 to facilitate deprotonation of the carboxylic acid during turnover.

Structural aspects of activation pathways of aspartic protease zymogens and viral 3C protease precursors

The three-dimensional structures of the inactive protein precursors (zymogens) of the serine, cysteine, aspartic, and metalloprotease classes of proteolytic enzymes are known. Comparisons of these structures with those of the mature, active proteases reveal that, in general, the preformed, active conformations of the residues involved in catalysis are rendered sterically inaccessible to substrates by the residues of the zymogens’ N-terminal extensions or prosegments. The prosegments interact in nonsubstrate-like fashions with the residues of the active sites in most of the cases. The gastric aspartic proteases have a well-characterized zymogen conversion pathway. Structures of human progastricsin, the inactive intermediate 2, and active human pepsin are known and have been used to define the conversion pathway. The structure of the zymogen precursor of plasmepsin II, the malarial aspartic protease, shows a new twist on the mode of inactivation used by the gastric zymogens. The prosegment of proplasmepsin disrupts the active conformation of the two catalytic aspartic acid residues by inducing a major reorientation of the two domains of the mature protease. The picornaviral 2A and 3C proteases have a chymotrypsin-like tertiary structure but with a cysteine nucleophile. These enzymes cleave themselves from the viral polyprotein in cis (intramolecular cleavage) and carry out trans cleavages of other scissile peptides important for the virus life cycle. Although the structure of the precursor viral polyprotein is unknown, it probably resembles the organization of the proenzymes of the bacterial serine proteases, subtilisin, and α-lytic protease. Cleavage of the prosegment is known to occur in cis for these precursor molecules.

Alterations in the Cytoskeleton Accompany Aluminum-Induced Growth Inhibition and Morphological Changes in Primary Roots of Maize1

Although Al is one of the major factors limiting crop production, the mechanisms of toxicity remain unknown. The growth inhibition and swelling of roots associated with Al exposure suggest that the cytoskeleton may be a target of Al toxicity. Using indirect immunofluorescence microscopy, microtubules and microfilaments in maize (Zea mays L.) roots were visualized and changes in their organization and stability correlated with the symptoms of Al toxicity. Growth studies showed that the site of Al toxicity was associated with the elongation zone. Within this region, Al resulted in a reorganization of microtubules in the inner cortex. However, the orientation of microtubules in the outer cortex and epidermis remained unchanged even after chronic symptoms of toxicity were manifest. Auxin-induced reorientation and cold-induced depolymerization of microtubules in the outer cortex were blocked by Al pretreatment. These results suggest that Al increased the stability of microtubules in these cells. The stabilizing effect of Al in the outer cortex coincided with growth inhibition. Reoriented microfilaments were also observed in Al-treated roots, and Al pretreatment minimized cytochalasin B-induced microfilament fragmentation. These data show that reorganization and stabilization of the cytoskeleton are closely associated with Al toxicity in maize roots.

Autonomic Straightening after Gravitropic Curvature of Cress Roots1

Few studies have documented the response of gravitropically curved organs to a withdrawal of a constant gravitational stimulus. The effects of stimulus withdrawal on gravitropic curvature were studied by following individual roots of cress (Lepidium sativum L.) through reorientation and clinostat rotation. Roots turned to the horizontal curved down 62° and 88° after 1 and 5 h, respectively. Subsequent rotation on a clinostat for 6 h resulted in root straightening through a loss of gravitropic curvature in older regions and through new growth becoming aligned closer to the prestimulus vertical. However, these roots did not return completely to the prestimulus vertical, indicating the retention of some gravitropic response. Clinostat rotation shifted the mean root angle −36° closer to the prestimulus vertical, regardless of the duration of prior horizontal stimulation. Control roots (no horizontal stimulation) were slanted at various angles after clinostat rotation. These findings indicate that gravitropic curvature is not necessarily permanent, and that the root retains some commitment to its equilibrium orientation prior to gravitropic stimulation.

Caracterização do perfil audiológico de escolares de escola pública do município de Bauru/SP

Muitos dos problemas auditivos não são notados por pais e professores. Este fato prejudica a aprendizagem da criança principalmente no ambiente escolar. Por isso, programas de triagem auditiva podem ser utilizados com o intuito de detectar e, posteriormente, diagnosticar escolares a fim de que se possa prevenir ou minimizar o impacto a que possíveis sequelas auditivas venham prejudicar o rendimento escolar da criança. Hoje em dia podemos contar com programas que permitem o melhor acompanhamento de populações que necessitam de cuidados preventivos e curativos, e a audição é um aspecto muito importante que pode ser avaliado quando estes programas são colocados em prática. O Programa Nacional de Reorientação da Formação Profissional em Saúde (Pró-Saúde), que visou reorientar a formação profissional, teve como objetivo integrar ensino-serviço e promover atenção básica por meio da abordagem integral do processo saúde-doença. Ambientes externos podem ser utilizados por alunos e professores universitários para que possam colocadas em prática ações que possibilitem a humanização das práticas de atenção a saúde e a integralidade das mesmas, por meio da articulação de ações e serviços de saúde, preventivos e curativos, individuais e coletivos. A escola é considerada um dos ambientes que este trabalho pode ser realizado. O Programa Saúde na Escola (PSE) abre o ambiente escolar com a finalidade de contribuir para a formação integral dos estudantes da rede pública de educação básica por meio de ações de prevenção, promoção e atenção à saúde. Sendo um estudo do tipo retrospectivo transversal, como objetivo principal caracterizar o perfil audiológico de escolares de escola pública do município de Bauru SP, contando com a integração de profissionais da área da saúde e educação no ambiente escolar, o que teve como base os programas citados acima. A triagem auditiva foi realizada com a aplicação dos seguintes procedimentos: imitanciometria, inspeção visual do meato acústico externo, emissões otoacústicas por produto de distorção e audiometria tonal liminar. Observou-se que do total de 652 estudantes, a grande maioria (97,1%) dos participantes com faixa etária entre 10 e 18 anos, apresentaram audição normal. Em 2,9% desta população foi encontrada alguma alteração auditiva temporária. Com a exceção de um único participante, portador de perda auditiva sensorioneural. Apesar de encontrarmos muitas crianças e adolescentes com audição normal, o que mais ressalta a importância deste trabalho é a necessidade da triagem auditiva em ambientes escolares e, essencialmente, o acompanhamento das mesmas nesta faixa etária, já que são escassos os estudos referentes a ela. Apesar das poucas alterações auditivas encontradas serem passageiras, são exatamente estas que interferem no bom rendimento escolar e outros fatores.

Role Expectations and State Socialization: Germany's Rediscovery of the Use of Force 1990-1995

This dissertation engages the question of why German political elites accepted the use of force during the 1990s and started to commit the country's armed forces to multilateral peacekeeping missions. Previous governments of the Federal Republic had opposed foreign deployment of the military and Germany was characterized by a unique strategic culture in which the efficacy of military force was widely regarded as negative. The rediscovery of the use of force constituted a significant reorientation of German security policy with potentially profound implications for international relations. I use social role theory to explain Germany's security policy reorientation. I argue that political elites shared a national role conception of their country as a dependable and reliable ally. Role expectations of the international security environment changed as a result of a general shift to multilateral intervention as means to address emerging security problems after the Cold War. Germany's resistance to the use of force was viewed as inappropriate conduct for a power possessing the economic and military wherewithal of the Federal Republic. Elites from allied countries exerted social pressure to have Germany contribute commensurate with capabilities. German political elites adapted role behavior in response to external expectations in an effort to preserve the national role conception of a dependable and reliable ally. Security policy reorientation to maintain Germany's national role conception was pursued by conservative elites who acted as 'role entrepreneurs'. CDU/CSU politicians initiated a process of role adaptation to include the use of force for non-defensive missions. They persuaded Social Democrats and Alliance 90/Green party politicians that the maintenance of the country's role conception necessitated a reorientation in security policy to accommodate the changes in the security environment.

I'm Not Who I Thought I Was: A Contextual Resolution to the Identity Loss of Combat PTSD.

Given the historical rates of combat post-traumatic stress disorder (PTSD), one can expect 30% of soldiers returning from current military conflicts to suffer from PTSD. For these individuals, various cognitive behavioral therapies (CBT) are the most commonly employed treatments. Unfortunately, however, symptom relapse can be expected with the various CBT approaches, as traumatic memories remain. Soldiers are imbued with a militarized identity, and the identity loss experienced by those soldiers who suffer from PTSD is particularly painful for this population, as the militarized identity effectively disavows personal suffering. For this reason, many combat veterans diagnosed with post-traumatic stress disorder experience undue, prolonged suffering as they struggle to make sense of the different person they fear they have become. This paper contrasts certain versions of Western philosophy, which view the self as a fixed and reified entity with certain versions of Eastern philosophy, which view the self as more contextual and fluid, in order to illuminate the value of employing third wave behavioral treatments, specifically Acceptance and Commitment Therapy (ACT), to treat the identity loss experienced by military veterans with PTSD. ACT echoes the Buddhist principle that attachment to verbally-constructed conceptual notions of self contribute to undue suffering, and that more vital living can be achieved by assuming a more contextual and experiential perspective on identity. Research and anecdotal accounts are cited to illustrate why treatment for identity loss associated with combat PTSD should be less focused on reconstructing a historically substance-oriented self and more focused on an epistemological reorientation to a deconstructed, contextual self.

Optical spin transfer in ferromagnetic semiconductors

Circularly polarized laser pulses that excite electron-hole pairs across the band gap of (III,Mn)V ferromagnetic semiconductors can be used to manipulate and to study collective magnetization dynamics. The initial spin orientation of a photocarrier in a (III,V) semiconductors is determined by the polarization state of the laser. We show that the photocarrier spin can be irreversibly transferred to the collective magnetization, whose dynamics can consequently be flexibly controlled by suitably chosen laser pulses. As illustrations we demonstrate the feasibility of all optical ferromagnetic resonance and optical magnetization reorientation.

Optical spin transfer in ferromagnetic semiconductors [poster]

Poster presented in the International Conference of Magnetism, Rome, July 2003.

New data on the Vrancea Nappe (Moldavidian Basin, Outer Carpathian Domain, Romania): paleogeographic and geodynamic reconstructions

A study has been performed on the Cretaceous to Early Miocene succession of the Vrancea Nappe (Outer Carpathians, Romania), based on field reconstruction of the stratigraphic record, mineralogical-petrographic and geochemical analyses. Extra-basinal clastic supply and intra-basinal autochthonous deposits have been differentiated, appearing laterally inter-fingered and/or interbedded. The main clastic petrofacies consist of calcarenites, sub-litharenites, quartzarenites, sub-arkoses, and polygenic conglomerates derived from extra-basinal margins. An alternate internal and external provenance of the different supplies is the result of the paleogeographic re-organization of the basin/margins system due to tectonic activation and exhumation of rising areas. The intra-basinal deposits consist of black shales and siliceous sediments (silexites and cherty beds), evidencing major environmental changes in the Moldavidian Basin. Organic-matter-rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting. The black shales display relatively high contents in sub-mature to mature, Type II lipidic organic matter (good oil and gas-prone source rocks) constituting a potentially active petroleum system. The intra-basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the Oligocene part of the succession can be correlated with volcanic supplies. The integration of all the data in the “progressive reorientation of convergence direction” Carpathian model, and their consideration in the framework of a foreland basin, led to propose some constrains on the paleogeographic-geodynamic evolutionary model of the Moldavidian Basin from the Late Cretaceous to the Burdigalian.

Closing the gap? Military co-operation from the Baltic Sea to the Black Sea. OSW Report, December 2012

The contracting defence budgets in Europe, the difficulties in developing the EU’s security policy, NATO's transformation, the reorientation of US security policy and the problems experienced by European defence industries – all together have in recent years created an increased interest in political, military and military-technological co-operation in Europe.It has manifested itself in concepts of closer co-operation within NATO and the EU (smart defence and pooling&sharing), bilateral and multilateral initiatives outside the structures of NATO and the EU (such as the Nordic Defence Co-operation or the Franco-British co-operation) and debates about the prerequisites, principles and objectives of bilateral, multilateral and regional security and defence co-operation. The present report aims to analyse the potential for security and defence co-operation among selected countries in the area between the Baltic Sea and the Black Sea, i.e. the Nordic states (Denmark, Finland, Norway and Sweden), the Baltic states (Lithuania Latvia and Estonia), Poland's partners in the Visegrad Group (the Czech Republic, Hungary and Slovakia) as well as Romania and Bulgaria. The authors were guided by the assumption that those states are Poland's natural partners for closer regional military co-operation. It may complement ‘the Western’ direction of Poland's security and defence policy, i.e. relations with the partners from the Weimar Triangle and the US. Its goal is not to replace the existing security structures but rather to strengthen military capabilities in the region within NATO and the EU.

Russia and its Near Neighborhood: Competition and Conflict within the EU. Natolin Research Paper 04/May 2011

Russia in 2004 politely rejected the offer to become a participant in the European Neighbourhood Policy, preferring instead to pursue bilateral relations with the EU under the heading of ‘strategic partnership’. Five years later, its officials first reacted with concern to the ENP’s eastern dimension, the Eastern Partnership initiative. Quickly, however, having become convinced that the project would not amount to much, their concern gave way to indifference and derision. Furthermore, Russian representatives have failed to support idealistic or romantic notions of commonality in the area between Russia and the EU, shunned the terminology of ‘common European neighbourhood’ and replaced it in EU-Russian documents with the bland reference to ‘regions adjacent to the EU and Russian borders’. Internally, the term of the ‘near abroad’ was the official designation of the area in the Yeltsin era, and unofficially it is still in use today. As the terminological contortions suggest, Moscow officials consider the EU’s eastern neighbours as part of a Russian sphere of influence and interest. Assurances to the contrary notwithstanding, they look at the EU-Russia relationship as a ‘zero-sum game’ in which the gain of one party is the loss of the other. EU attempts to persuade the Russian power elite to regard cooperation in the common neighbourhood not as a competitive game but providing ‘win-win’ opportunities have been to no avail. In fact, conceptual approaches and practical policies conducted vis-à-vis the three Western CIS countries (Belarus, Ukraine and Moldova) and the southern Caucasus (Georgia, Armenia and Azerbaijan) confirm that, from Moscow’s perspective, processes of democratisation, liberalisation and integration with Western institutions in that region are contrary to Russian interests. In each and every case, therefore, the area’s ‘frozen conflicts’ have not been regarded by the Kremlin as an opportunity to promote stability and prosperity in the countries concerned but as an instrument to prevent European choices in their domestic and foreign policy. The current ‘reset’ in Russia’s relations with the United States and the ‘modernisation partnership’ with the EU have as yet failed to produce an impact on Russia’s policies in ‘its’ neighbourhood. The EU is nevertheless well advised to maintain its course of attempting to engage that country constructively, including in the common neighbourhood. However, its leverage is small. For any reorientation to occur in Moscow towards perceptions and policies of mutual benefit in the region, much would depend on Russia’s internal development.

Disentangling the Reform Gridlock: Higher Education in Germany. CES Germany & Europe Working Papers, No. 02.7, 2002

For more than a decade, bemoaning the many roadblocks to reforming important aspect of German politics has become commonplace. Explanations emphasize formal and informal veto points, such as the role of political institutions and the lack of elite and societal support for reform initiatives. Against this background, I was interested in factors that place policy issues on the political agenda and follow up with concrete courses of action; i.e., in factors that lead to a disentangling of the reform gridlock. I emphasize the importance of agenda setting in the emergence of higher education reform in Germany. Globalization, European integration and domestic pressures combined to create new pressures for change. In response, an advocacy coalition of old and new political actors has introduced a drawn-out and ongoing process of value reorientation in the direction of competition, including international competition, and greater autonomy. The result has been a burst of activities, some moderate, some more far-reaching in their potential to restructure German higher education.