Light induces oxidative damage and protein stability in the fungal photoreceptor Vivid

"Flavin-binding photoreceptor proteins sense blue-light (BL) in diverse organisms and have become core elements in recent optogenetic applications. The light-oxygen-voltage (LOV) protein Vivid (VVD) from the filamentous fungus Neurospora crassa is a classic BL photoreceptor, characterized by effecting a photocycle based on light-driven formation and subsequent spontaneous decay of a flavin-cysteinyl adduct. Here we report that VVD presents alternative outcomes to light exposure that result in protein self-oxidation and, unexpectedly, rise of stability through kinetic control. Using optical absorbance and mass spectrometry we show that purified VVD develops amorphous aggregates with the presence of oxidized residues located at the cofactor binding pocket. Light exposure increases oxidative levels in VVD and specific probe analysis identifies singlet oxygen production by the flavin. These results indicate that VVD acts alternatively as a photosensitizer, inducing self-oxidative damage and subsequent aggregation. Surprisingly, BL illumination has an additional, opposite effect in VVD. We show that light-induced adduct formation establishes a stable state, delaying protein aggregation until photoadduct decay occurs. In accordance, repeated BL illumination suppresses VVD aggregation altogether. Furthermore, photoadduct formation confers VVD stability against chemical denaturation. Analysis of the aggregation kinetics and testing of stabilizers against aggregation reveal that aggregation in VVD proceeds through light-dependent kinetic control and dimer formation. These results uncover the aggregation pathway of a photosensor, where light induces a remarkable interplay between protein damage and stability.

Functional evaluation of the pelvic floor muscles and the sexuality of women with recurrent vulvovaginal candidiasis and vulvodynia

Orientadores: Paulo César Giraldo, Cássia Raquel Teatin JuliatoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: Introdução: Candidíase vulvovaginal recorrente (CVVR) e vulvodínia (VVD) cursam com dor e desconforto vulvoperineal, o que afeta a vida da mulher nas esferas: sexual, afetiva, social, e psíquica. Objetivo: Avaliar a função da musculatura do assoalho pélvico (MAP) e da sexualidade de mulheres com CVVR ou VVD. Desenho do estudo: Estudo de corte transversal com 61 mulheres entre 18 e 50 anos e sexualmente ativas, sendo 19 mulheres com VVD, 12 mulheres com CVVR e 30 assintomáticas (controles). A função da MAP foi avaliada através de eletromiografia de superfície (sEMG) e de registro da pressão vaginal (PV), utilizando-se o aparelho "Miotool Uro" e o "software Biotrainer" (Miotec LTDA). A função sexual foi avaliada através do questionário "Female Sexual Function Index" (FSFI) que consta de 19 questões, agrupadas em 6 domínios (desejo sexual, excitação, lubrificação vaginal, orgasmo, satisfação sexual e dor). Resultados: As mulheres com CVVR e VVD apresentaram potenciais elétricos da MAP, evidenciados pela sEMG, significativamente menores que os controles, porém não foram encontradas diferenças significativas entre as mulheres portadoras de CVVR, VVD e controles para os valores eletromiograficos do tônus basal e pressão vaginal no repouso ou nas contrações da MAP. Da mesma forma mulheres com CVVR e VVD apresentaram um tempo máximo de contração sustentada significativamente menor que os controles. Mulheres com VVD apresentaram um pior desempenho sexual (excitação, lubrificação, orgasmo, satisfação sexual e dor). Apenas o desejo sexual não foi pior que das mulheres controles. Nas mulheres com CVVR estas diferenças não foram tão evidentes, havendo comprometimento apenas dos domínios orgasmo e satisfação. O escore total de pontuação do grupo CVVR foi 25 (±5), do VVD 21 (±5) e dos controles de 29 (±4) (p<0,05). Conclusão: Mulheres com VVD e CVVR apresentam disfunção da MAP e qualidade de vida sexual inferior aos controlesAbstract: Introduction: Recurrent vulvovaginal candidiasis (RVVC) and vulvodynia (VVD) are characterized by pain and vulvoperineal discomfort, which may affect a woman's life in the sexual, affective, social and psychological spheres. Objective: To evaluate pelvic floor muscle (PFM) function and sexuality in women with RVVC or VVD. Study design: A cross-sectional study conducted with 61 sexually active women (age range: 18 to 50 years). Of the total women, 19 had VVD, 12 had RVVC caused by Candida and 30 were asymptomatic (controls). PFM function was evaluated by surface electromyography (sEMG) and vaginal pressure (PV) recording. A "Miotool Uro" device and Biotrainer" software (Miotec Ltd) were used for this purpose. Sexual function was assessed by the "Female Sexual Function Index" (FSFI) questionnaire including 19 questions, grouped into 6 domains (sexual desire, arousal, vaginal lubrication, orgasm, sexual satisfaction and pain). Results: The electrical potential of the PFM in women with RVVC and VVD as evidenced by sEMG was significantly lower than in the controls. However, no significant differences were found among women with RVVC, those with VVD and controls for electromyography values at basal tone and vaginal pressure at rest or PFM contractions. Similarly, the maximum time of sustained contraction in women with RVVC and VVD was significantly lower than in women in the control group. Women with VVD had a worse sexual performance (arousal, lubrication, orgasm, sexual satisfaction and pain). Only sexual desire was not worse in these women compared to the control group. In women with RVVC, these differences were not sufficiently evident and only the domains of orgasm and satisfaction were compromised. The total score was 25 (±5) for the RVVC group, 21 (±5) for the VVD group and 29 (±4) for the control group (p<0.05). Conclusion: Women with VVD and RVVC had PFM dysfunction and a lower sexual quality of life than women in the control groupMestradoFisiopatologia GinecológicaMestre em Ciências da Saúd

Physical Interaction Between VIVID and White Collar Complex Regulates Photoadaptation in Neurospora

Photoadaptation, the ability to attenuate a light response on prolonged light exposure while remaining sensitive to escalating changes in light intensity, is essential for organisms to decipher time information appropriately, yet the underlying molecular mechanisms are poorly understood. In Neurospora crassa, VIVID (VVD), a small LOV domain containing blue-light photoreceptor protein, affects photoadaptation for most if not all light-responsive genes. We report that there is a physical interaction between VVD and the white collar complex (WCC), the primary blue-light photoreceptor and the transcription factor complex that initiates light-regulated transcriptional responses in Neurospora. Using two previously characterized VVD mutants, we show that the level of interaction is correlated with the level of WCC repression in constant light and that even light-insensitive VVD is sufficient partly to regulate photoadaptation in vivo. We provide evidence that a functional GFP-VVD fusion protein accumulates in the nucleus on light induction but that nuclear localization of VVD does not require light. Constitutively expressed VVD alone is sufficient to change the dynamics of photoadaptation. Thus, our results demonstrate a direct molecular connection between two of the most essential light signaling components in Neurospora, VVD and WCC, illuminating a previously uncharacterized process for light-sensitive eukaryotic cells

The Prevalence of Gas Outflows in Type 2 AGNs. II. 3D Biconical Outflow Models

We present 3D models of biconical outflows combined with a thin dust plane for investigating the physical properties of the ionized gas outflows and their effect on the observed gas kinematics in type 2 active galactic nuclei (AGNs). Using a set of input parameters, we construct a number of models in 3D and calculate the spatially integrated velocity and velocity dispersion for each model. We find that three primary parameters, i.e., intrinsic velocity, bicone inclination, and the amount of dust extinction, mainly determine the simulated velocity and velocity dispersion. Velocity dispersion increases as the intrinsic velocity or the bicone inclination increases, while velocity (i.e., velocity shifts with respect to systemic velocity) increases as the amount of dust extinction increases. Simulated emission-line profiles well reproduce the observed [O III] line profiles, e.g., a narrow core and a broad wing components. By comparing model grids and Monte Carlo simulations with the observed [O III] velocity-velocity dispersion (VVD) distribution of ~39,000 type 2 AGNs, we constrain the intrinsic velocity of gas outflows ranging from ~500 km/s to ~1000 km/s for the majority of AGNs, and up to ~1500-2000 km/s for extreme cases. The Monte Carlo simulations show that the number ratio of AGNs with negative [O III] velocity to AGNs with positive [O III] velocity correlates with the outflow opening angle, suggesting that outflows with higher intrinsic velocity tend to have wider opening angles. These results demonstrate the potential of our 3D models for studying the physical properties of gas outflows, applicable to various observations, including spatially integrated and resolved gas kinematics.Comment: 14 pages, 14 figures, 2 tables; matched with the ApJ published versio

Structural properties of 1-planar graphs and an application to acyclic edge coloring

A graph is called 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we establish a local property of 1-planar graphs which describes the structure in the neighborhood of small vertices (i.e. vertices of degree no more than seven). Meanwhile, some new classes of light graphs in 1-planar graphs with the bounded degree are found. Therefore, two open problems presented by Fabrici and Madaras [The structure of 1-planar graphs, Discrete Mathematics, 307, (2007), 854-865] are solved. Furthermore, we prove that each 1-planar graph $G$ with maximum degree $\Delta(G)$ is acyclically edge $L$-choosable where $L=\max\{2\Delta(G)-2,\Delta(G)+83\}$.Comment: Please cite this published article as: X. Zhang, G. Liu, J.-L. Wu. Structural properties of 1-planar graphs and an application to acyclic edge coloring. Scientia Sinica Mathematica, 2010, 40, 1025--103

The performance of four possible rules for selecting the Prime Minister after the Dutch Parliamentary elections of June 2010

Economic policy depends not only on national elections but also on coalition bargaining strategies. In coalition government, minority parties bargain on policy and form a majority coalition, and select a Prime Minister from their mids. In Holland the latter is done conventionally with Plurality, so that the largest party provides the chair of the cabinet. Alternative methods are Condorcet, Borda or Borda Fixed Point. Since the role of the Prime Minister is to be above all parties and represent the nation and to be there for all citizens, it would enhance democracy and likely be optimal if the potential Prime Minister is selected from all parties and at the start of the bargaining process. The performance of the four selection rules is evaluated using the results of the 2010 Dutch Parliamentary elections. The impossibility theorem by Kenneth Arrow (Nobel memorial prize in economics 1972) finds a crucially different interpretation.Political economy; public choice; political science; optimal representation; electoral systems; elections; coalition; impossibility theorem