Recent advances into vanadyl, vanadate and decavanadate interactions with actin

Although the number of papers about ‘‘vanadium’’ has doubled in the last decade, the studies about ‘‘vanadium and actin’’ are scarce. In the present review, the effects of vanadyl, vanadate and decavanadate on actin structure and function are compared. Decavanadate 51V NMR signals, at 516 ppm, broadened and decreased in intensity upon actin titration, whereas no effects were observed for vanadate monomers, at 560 ppm. Decavanadate is the only species inducing actin cysteine oxidation and vanadyl formation, both processes being prevented by the natural ligand of the protein, ATP. Vanadyl titration with monomeric actin (G-actin), analysed by EPR spectroscopy, reveals a 1 : 1 binding stoichiometry and a Kd of 7.5 mM 1. Both decavanadate and vanadyl inhibited G-actin polymerization into actin filaments (F-actin), with a IC50 of 68 and 300 mM, respectively, as analysed by light scattering assays, whereas no effects were detected for vanadate up to 2 mM. However, only vanadyl (up to 200 mM) induces 100% of G-actin intrinsic fluorescence quenching, whereas decavanadate shows an opposite effect, which suggests the presence of vanadyl high affinity actin binding sites. Decavanadate increases (2.6-fold) the actin hydrophobic surface, evaluated using the ANSA probe, whereas vanadyl decreases it (15%). Both vanadium species increased the e-ATP exchange rate (k = 6.5 10 3 s 1 and 4.47 10 3 s 1 for decavanadate and vanadyl, respectively). Finally, 1H NMR spectra of G-actin treated with 0.1 mM decavanadate clearly indicate that major alterations occur in protein structure, which are much less visible in the presence of ATP, confirming the preventive effect of the nucleotide on the decavanadate interaction with the protein. Putting it all together, it is suggested that actin, which is involved in many cellular processes, might be a potential target not only for decavanadate but above all for vanadyl. By affecting actin structure and function, vanadium can regulate many cellular processes of great physiological significance

Decavanadate interactions with actin: cysteine oxidation and vanadyl formation

Incubation of actin with decavanadate induces cysteine oxidation and oxidovanadium(IV) formation. The studies were performed combining kinetic with spectroscopic (NMR and EPR) methodologies. Although decavanadate is converted to labile oxovanadates, the rate of deoligomerization can be very slow (half-life time of 5.4 h, at 25 ◦C, with a first order kinetics), which effectively allows decavanadate to exist for some time under experimental conditions. It was observed that decavanadate inhibits F-actin-stimulated myosin ATPase activity with an IC50 of 0.8 mMV10 species, whereas 50 mMof vanadate or oxidovanadium(IV) only inhibits enzyme activity up to 25%. Moreover, from these three vanadium forms, only decavanadate induces the oxidation of the so called “fast” cysteines (or exposed cysteine, Cys-374) when the enzyme is in the polymerized and active form, F-actin, with an IC50 of 1 mMV10 species. Decavanadate exposition to F- and G-actin (monomeric form) promotes vanadate reduction since a typical EPR oxidovanadium(IV) spectrum was observed. Upon observation that V10 reduces to oxidovanadium(IV), it is proposed that this cation interacts with G-actin (Kd of 7.48 ± 1.11 mM), and with F-actin (Kd = 43.05 ± 5.34 mM) with 1:1 and 4:1 stoichiometries, respectively, as observed by EPR upon protein titration with oxidovanadium(IV). The interaction of oxidovanadium(IV) with the protein may occur close to the ATP binding site of actin, eventually with lysine-336 and 3 water molecules

Variabilidade e reprodutibilidade da análise das medições ecocardiográficas na estenose valvular aórtica

Background: Doppler echocardiography is the most frequent method for detecting and evaluating the severity of valvular aortic stenosis. The aim of this study was to assess the variability and reproducibility of echocardiographic parameters including aortic valve area (AVA), peak aortic jet velocity (Vmax), velocity ratio (VLVOT/Vmax), peak gradient (Gmax) and mean gradient (Gmean) in aortic stenosis (AS) patients. Methods: Doppler echocardiograms were obtained from 150 randomly selected patients (56.7% male; mean age 73±9 years) with asymptomatic moderate aortic valve stenosis. The echocardiographic measurements were performed by two independent level III (expert) blinded observers. To assess intra-observer variability, we evaluated parameters of AS progression at two different times (mean of two weeks after the first examination). Results: For intra-observer variability (observer 1), the variation and reproducibility coefficients were, respectively, 1.88% and 0.16 m/s for Vmax, 2.08% and 0.14 for VLVOT/Vmax, 2.05% and 0.18 cm2 for AVA, 3.89% and 5.18 mmHg for Gmax and 7.87% and 6.30 mmHg for Gmean. For inter-observer variability, the variation and reproducibility coefficients were, respectively, 2.00% and 0.14 m/s for Vmax, 2.91% and 0.14 for VLVOT/Vmax, 7.67% and 0.16 cm2 for AVA, 8.53% and 7.06 mmHg for Gmean and 3.90% and 5.58 mmHg for Gmax. Both intra- and inter-observer studies showed excellent intraclass correlation coefficients (ICC) for all echocardiographic parameters (ICC ranged from 0.943 to 0.990 for intra-observer variability and from 0.955 to 0.992 for interobserver variability). Conclusion: Doppler echocardiographic measurements of AVA, Vmax, Gmax and Gmean are highly reproducible when performed by expert observers. Of all echocardiographic parameters, Vmax and VLVOT/Vmax showed the best variability and reproducibility, and thus constitute reliable tools for clinical and research purposes in aortic stenosis diagnosis and follow-up.Introdução: A ecocardiografia Doppler é o método mais frequente de detecção e avaliação da gravidade da estenose valvular aórtica. O objectivo deste estudo foi avaliar a variabilidade e reprodutibilidade dos parâmetros ecocardiográficos como a área valvular aórtica (AVA), velocidade pico (Vmax), relação de velovidades (VLVOT/Vmax), gradiente pico (Gmax) e gradiente médio (Gmédio) nos doentes com estenose aórtica. Métodos: Um ecocardiograma Doppler foi realizado em 60 doentes consecutivos seleccionados aleatoriamente (da população do estudo RAAVE) com estenose aórtica moderada a grave assintomática (56.7% sexo masculino; idade média 73 ± 9 anos). As medidas ecocardiográficas foram efectuadas por dois ecocardiografistas de nível III numa estratégia de dupla ocultação. Para o estudo da variabilidade intra-observador, avaliamos os prâmetros de progressão da estenose aórtica em dois momentos diferentes (média de duas semanas após o 1.º exame). Resultados: No que respeita à variabilidade intra-observador (observador 1), os coeficientes de variação e reprodutibilidade foram, respectivamente, 1.88% e 0.16 m.s-1 para a Vmax, 2.08% e 0.14 cm2 para a VLVOT/Vmax, 2.05% e 0.18 ms-1 para a AVA, 3.89% e 5.18 mmHg para Gmax and 7.87% e 6.30 mmHg para o Gmédio. No que respeita à variabilidade inter- -observador, os coeficientes de variação e reprodutibilidade foram, respectivamente, 2.00% e 0.14 m.s-1 para a Vmax, 2.91% e 0.14 m.s-1 para a relação VLVOT/Vmax, 7.67% e 0.16 cm2 para a AVA, 8.53% e 7.06 mmHg para o Gmédio e 3.90% e 5.58 mmHg para o Gmax. Os estudos intra-observador e inter-observador mostraram ter excelentes coeficientes de correlação intra-classe (CCI), para todos os parâmetros ecocardiográficos (CCI varia de 0.943 até 0.990 para a variabilidade intra- -observador e de 0.955 até 0.992 para a variabilidade inter-observador). Conclusões: As medições ecocardiográficas da AVA, Vmax, Gmax and Gmédio são altamente reprodutíveis quando realizadas por ecocardiografistas experientes. De todos os parâmetros ecocardiográficos a Vmax e a relação VLVOT/Vmax apresentam os melhores valores de variabilidade e reprodutibilidade e assim constituem provavelmente a melhor ferramenta no diagnóstico e seguimento criterioso dos doentes com estenose valvular aórtica.info:eu-repo/semantics/publishedVersio

Stimulating fertility awareness: the importance of getting the language right

While education about fertility is not intrinsically controversial, finding the right language to communicate the topic can be challenging, as there are several risks of unintended negative effects such as dissonance, anxiety, culpability, and stigma due to social norming. In this article, we share some of our learnings from promoting fertility awareness in the hope that they will inspire further debate and research on this topic. Starting from the ethical principles of respect for reproductive autonomy, avoiding harm (in terms of stigma or anxiety) and inclusivity, we have formulated five recommendations: (i) frame fertility awareness messages with (reproductive) autonomy in mind and aim to be inclusive of those who do not represent the traditional nuclear family; (ii) be empathetic and steer clear of blame; (iii) avoid scaremongering and offer a positive angle; (iv) give due consideration to both women and men in fertility health messaging; and (v) tailor the messages to particular contexts and audiences and develop resources in close collaboration with the target groups

Property change in ZrNxOy thin films: effect of the oxygen fraction and bias voltage

The main purpose of this work consists on the preparation of single layered zirconium oxynitride, ZrNxOy, thin films, deposited by rf reactive magnetron sputtering. The depositions were carried out by varying the process parameters such as substrate bias voltage and flow rate of the reactive gases. Independently of O content, the samples prepared with oxygen fractions revealed crystalline structures basically constituted by face centred cubic ZrN grains. Atomic force microscopy (AFM) observation showed lower values of surface roughness for low oxygen fractions and a second region where roughness grows significantly, corresponding to the highest oxygen fractions. Ion bombardment promoted a continuous smoothing of the surface up to a bias voltage of -66 V. At a bias voltage of -75 V, roughening is again observed. The small increase of film hardness in low oxygen fractions ZrNxOy films was attributed to lattice distortions occurring as a result of the possible oxygen incorporation within the ZrN lattice and also grain size reduction. Residual stresses appeared to be an important parameter to explain the observed behaviour, namely in the group of samples prepared with variation in the bias voltage. Regarding colour variations, it was observed a clear dependence of the obtained colorations with oxygen fraction.http://www.sciencedirect.com/science/article/B6TW0-4D98KMK-9/1/e9723e69843e56c913d089e23ec8ff2

Produção de biomassa e valor nutricional do Cajanus cajan cv. Mandarin sob manejo orgânico e convencional.

O objetivo deste estudo foi comparar a produção de matéria seca (MS kg.ha), os teores de matéria seca (MS%), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) do Cajanus Cajan cv. Mandarin, sob manejo orgânico e convencional. No manejo orgânico foram utilizados o calcário dolomítico, gesso mineral, cama de frango, termofosfato magnesiano e termopotássio. E no manejo convencional foram utilizados o calcário dolomítico, fosfogesso, uréia, supertriplo e cloreto de potássio. Na análise estatística foi utilizado o delineamento inteiramente casualisado, no esquema de parcelas subdivididas com dois tratamentos e seis repetições. Os resultados obtidos para a MS kg.ha, MS%, FDN% e FDA% foram de 13310,7 kg.ha, 53,6%, 57,9% e 41,7% para o manejo orgânico e 13.142,3 kg.ha, 46,7%, 53,5% e 40,3% para o convencional, respectivamente. Não houve diferenças entre os manejos adotados para nenhum dos parâmetros estudados com exceção da FDN% que foi superior para a leguminosa em sistema orgânico. Abstract: The objective of this study was to compare the Dry matter production (DM kg. ha), the levels of dry matter (DM), neutral (NDF) and acid detergent fiber (FDA) of Cajanus cajan cv. Mandarin between organic and conventional management. In organic management was used the dolomitic limestone, mineral gypsum, chicken manure, magnesium thermophosphate and thermopotassium. In conventional management were used dolomitic limestone, phosphogypsum, urea, superphosphate and potassium chloride. The experiment was divided into randomized design in split plots with two treatments and six repetitions. The results obtained for the MS kg. ha, MS%, NDF% and FDA% were 13310.7 kg. ha, 53.6% 57.9% and 41.7% for the organic management and 13142. 3 kg. ha, 46.7%, 53.5% and 40.3% for the conventional respectively. No differences were found between the adopted management for any parameters studied except for the NDF% that was superior to the legumes in organic system

Produção de matéria seca e composição química do Pennisetum purpureum cv. Canará sob manejo orgânico e convencional.

Foram comparados a produção de matéria seca (Ms kg.ha), os teores de matéria seca (MS%), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) do capim elefante (Pennisetum purpureum cv. Canará) sob manejo orgânico e convencional. No manejo orgânico foram utilizados o calcário dolomítico, gesso mineral, cama de frango, termofosfato magnesiano e termopotássio. No manejo convencional foram utilizados o calcário dolomítico, fosfogesso, uréia, supertriplo e cloreto de potássio. O experimento foi divido no delineamento inteiramente casualizado, em esquema de parcelas subdivididas com dois tratamentos e seis repetições. Os resultados obtidos de MS kg.ha, MS%, FDN% e FDA% foram de 25.957,91 kg.ha; 19,48%; 64,36% e 37,06% para o manejo orgânico e de 14.513,08 kg.ha; 16,68%; 63,91% e 36,69%, respectivamente para o convencional. O manejo orgânico proporcionou maior produção de matéria seca em relação ao convencional. Abstract: Dry matter yield (DM kg.ha), dry matter (DM%), neutral (NDF) and acid detergent fiber (ADF) levels of Elephant grass (Pennisetum purpureum cv. Canará) were compared under organic and conventional management. In organic management was used the dolomitic limestone, mineral gypsum, chicken manure, magnesium thermophosphate and thermopotassium. In conventional management were used dolomitic limestone, phosphogypsum, urea, superphosphate and potassium chloride. The experiment was divided into randomized design in split plots with two treatments and six repetitions. The results of DM kg.ha, DM%, NDF% and ADF% were 25957.91 kg.ha, 19.48%, 64.36% and 37.06% respectively for the organic management and 14513.08 kg.ha, 16.68%, 63.91% and 36.69% respectively for the conventional management. The organic management provided higher dry matter production in relation to the conventional

Análise comparativa para a produtividade em arroz por populações segregantes de Epagri 108 x Irat 122 avançadas por Bulk e SSD.

O objetivo desse trabalho, portanto, foi comparar a produtividade das linhagens avançadas por SSD (F8) com a produtividade das linhagens avançadas por Bulk (F7: 8). Adicionalmente, todas as linhagens estão sendo analisadas por marcadores SNPs, obtidos pela técnica de DArTseq, o que possibilitará inferir a distância genética entre elas e comparar o percentual da variação fenotípica explicada pelos QTLs para produtividade identificados nos dois conjuntos de linhagens (derivadas dos métodos Bulk e SSD)