Isolamento e caracterização de proteínas envolvidas na via desnitrificante em Pseudomonas Chlororaphis

Dissertação de Doutoramento em Química apresentada à Faculdade de Ciências da Universidade do PortoO crescimento das estirpes DSM 50135 e 50083T de Pseudomonas chlororaphis em condições microaeróbicas na presença de nitrato produziu células com expressão abundante de metaloproteínas. Da estirpe DSM 50135, que se revelou um bom sistema para expressão das proteínas envolvidas na desnitrificação, isolou-se uma azurina (Az626), uma redutase do nitrito contendo cobre (CuNiR) e uma redutase membranar do nitrato (NaR). A indução da desnitrificação na estirpe DSM 50083T revelou-se mais problemática do que na DSM 50135, tendo-se purificado desta estirpe apenas uma azurina (Az624) e, parcialmente, uma proteína com actividade de redutase do nitrito.As azurinas das estirpes de Ps. chlororaphis estudadas (Az624 e Az626) apresentam vários comportamentos que as distinguem das outras azurinas conhecidas. Têm um carácter mais acídico e potenciais de redução mais elevados do que a maioria das azurinas descritas na literatura e apresentam uma dependência do potencial com o pH semelhante à observada em Ps. aeruginosa, mas em que os valores menores de pK das formas oxidadas sugerem maiores mudanças estruturais associadas ao processo de oxidação. Observa-se uma dependência inédita do coeficiente de difusão de Az624 com o pH, que poderá ser devida a mudanças conformacionais, ou à formação de agregados supramoleculares associados ao processo de protonação. Em ambas as azurinas detecta-se estrutura super-hiperfina no espectro de ressonância paramagnética electrónica (RPE) em banda X, comportamento descrito apenas para uma outra azurina, isolada de uma estirpe aparentada, Ps. aureofaciens ATCC 13985 (Zumft et al., 1987).A redutase do nitrito isolada de Ps. chlororaphis DSM 50135 é uma enzima azul, que contém dois tipos de centros de cobre, tipo-1 (T1Cu) e tipo-2 (T2Cu), tal como as restantes CuNiRs conhecidas. Neste trabalho efectuou-se pela primeira vez uma determinação directa dos potenciais de ambos os centros de cobre numa CuNiR: T2Cu, 172 mV e T1Cu, 298 mV a pH 7.6. Embora os valor ..

Evidence for modulation of the rate of intramolecular electron transfer through nitrite binding to the type 2 copper center

Eur. J. Biochem. 271, 2361–2369 (2004)The nitrite reductase (Nir) isolated from Pseudomonas chlororaphis DSM 50135 is a blue enzyme, with type 1 and type 2 copper centers, as in all copper-containing Nirs described so far. For the first time, a direct determination of the reduction potentials of both copper centers in a Cu-Nir was performed: type 2 copper (T2Cu), 172 mV and type 1 copper (T1Cu), 298 mV at pH 7.6. Although the obtained values seem to be inconsistent with the established electrontransfer mechanism, EPR data indicate that the binding of nitrite to the T2Cu center increases its potential, favoring the electron-transfer process. Analysis of the EPR spectrum of the turnover form of the enzyme also suggests that the electron-transfer process between T1Cu and T2Cu is the fastest of the three redox processes involved in the catalysis: (a) reduction of T1Cu; (b) oxidation of T1Cu by T2Cu; and(c) reoxidation of T2Cu by NO2 –. Electrochemical experiments showthat azurin from the same organism can donate electrons to this enzyme

Regulation of the Renin-Angiotensin-Aldosterone System by Reactive Oxygen Species

Angiotensin II (Ang II), the major effector of the renin-angiotensin-aldosterone system (RAAS), stimulates the production of reactive oxygen species (ROS) which are critically involved in Ang II-induced effects. Noteworthy, accumulating evidence indicates that ROS also regulate the activation of RAAS, contributing to the fine-tuning of this system under physiological conditions or to the amplification of the deleterious signaling in several pathologies. This chapter aims at giving an overview of the role of ROS in the regulation of expression, secretion and/or activity of several RAAS components

Insuficiência adrenal primária como primeira manifestação de câncer pulmonar metastático

Primary adrenal insufficiency is, in most cases, caused by infections and autoimmune adrenalitis. Adrenal metastasis are relatively common in lung cancer, but they are usually asymptomatic, even when bilateral. There are few reports of adrenal metastasis as a cause of adrenal insufficiency. We describe a case of primary adrenal insufficiency presenting as the first clinical manifestation of metastatic lung cancer. A 59 year-old, white, smoker woman, complaining of right flank pain associated with nausea and weight loss. Laboratory exams confirmed the diagnosis of primary adrenal insufficiency. It was started treatment with prednisone and fludrocortisone with progressive improvement. At the etiologic investigation, abdominal computadorized tomography (CT) showed bilateral increase of the adrenal glands. It was performed an adrenal biopsy and the cytologic study was positive for malignant cells. It was made another biopsy, of a supraclavicular limph node, and the histopathologic study revealed a metastatic adenocarcinoma, immunohistochemistry study suggested lung as the primary site. Awareness of this diagnosis is important because initial symptoms of adrenal insufficiency are unspecific and may misguidedly be attributed to the neoplasm.A insuficiência adrenal primária é, na maioria das vezes, causada por infecções e adrenalite auto-imune. Metástases adrenais são relativamente comuns em neoplasias de pulmão, mas usualmente são assintomáticas, mesmo quando bilaterais. Há poucos relatos de metástases adrenais levando à insuficiência adrenal. Descrevemos aqui um caso de insuficiência adrenal primária como primeira manifestação clínica de neoplasia pulmonar metastática. Paciente de 59 anos, feminina, branca, tabagista, queixava-se de dor em flanco direito associada a náuseas e emagrecimento. Exames laboratoriais confirmaram o diagnóstico de insuficiência adrenal primária. Iniciou tratamento com prednisona e fludrocortisona, com melhora progressiva dos sintomas. Na investigação da etiologia, tomografia computadorizada (TC) de abdômen mostrou aumento bilateral das adrenais. Foi submetida à biopsia de adrenal, com citopatológico positivo para células malignas. Linfonodo supraclavicular esquerdo foi biopsiado, com anátomo-patológico (AP) confirmando adenocarcinoma metastático, com imunohistoquímica sugerindo pulmão como sítio primário. Atentar para o diagnóstico de insuficiência adrenal nesse contexto é importante, porque os sintomas iniciais são inespecíficos, podendo ser atribuídos à neoplasia

Voluntary exercise does not increase gastrointestinal motility but increases spatial memory, intestinal eNOS, Akt levels, and Bifidobacteria abundance in the microbiome

The interaction between the gut and brain is a great puzzle since it is mediated by very complex mechanisms. Therefore, the possible interactions of the brain–exercise–intestine–microbiome axis were investigated in a control (C, N = 6) and voluntarily exercised (VE, N = 8) middle-aged rats. The endurance capacity was assessed by VO2max on the treadmill, spatial memory by the Morris maze test, gastrointestinal motility by EMG, the microbiome by 16S RNA gene amplicon sequencing, caveolae by electron microscopy, and biochemical assays were used to measure protein levels and production of reactive oxygen species (ROS). Eight weeks of voluntary running increased VO2max, and spatial memory was assessed by the Morris maze test but did not significantly change the motility of the gastrointestinal tract or production of ROS in the intestine. The protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) protein levels significantly increased in the intestine, while peroxisome proliferator–activated receptor gamma coactivator 1 alpha (PGC-1α), mitochondrial transcription factor A (TFAM), nuclear respiratory factor 1 (NFR1), SIRT1, SIRT3, nicotinamide phosphoribosyl transferase (NAMPT), and nuclear factor κB (NF-κB) did not change. On the other hand, voluntary exercise increased the number of caveolae in the smooth muscles of the intestine and relative abundance of Bifidobacteria in the microbiome, which correlated with the Akt levels in the intestine. Voluntary exercise has systemic effects and the relationship between intestinal Akt and the microbiome of the gastrointestinal tract could be an important adaptive response

Prevalence, awareness, treatment, and control of high low-density lipoprotein cholesterol in Brazil : baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND AND OBJECTIVES: Dyslipidemia is a pivotal risk factor for coronary heart disease (CHD). The purpose of this study was to identify the profile of dyslipidemia in a Brazilian population, according to high low-density lipoprotein (LDL-C) levels. We used the classification of the 2004 update of National Cholesterol Education Program Adult Treatment Panel III (ATP-III). METHODS: Of the 15,105 men and women aged 35 to 74 years enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), we included 14,648 subjects (97%). They had data to categorize them according to the NCEP-ATP-III criteria. We compared 4 categories: ‘‘0–1’’ risk factors, ‘‘2 or more risk factors’’, ‘‘CHD or CHD risk equivalent’’, and ‘‘CHD at very high risk’’. The sociodemographic determinants used were sex, age, ethnicity, income, education, and health insurance. Poisson regression was used to estimate the prevalence ratios for cholesterol (LDL-C), frequency, awareness, treatment, and control of high LDL-C

Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016

As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016

Global, regional, and national disability-adjusted life-years (DALYs) for 333 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND: Measurement of changes in health across locations is useful to compare and contrast changing epidemiological patterns against health system performance and identify specific needs for resource allocation in research, policy development, and programme decision making. Using the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we drew from two widely used summary measures to monitor such changes in population health: disability-adjusted life-years (DALYs) and healthy life expectancy (HALE). We used these measures to track trends and benchmark progress compared with expected trends on the basis of the Socio-demographic Index (SDI). METHODS: We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2016. We calculated DALYs by summing years of life lost and years of life lived with disability for each location, age group, sex, and year. We estimated HALE using age-specific death rates and years of life lived with disability per capita. We explored how DALYs and HALE differed from expected trends when compared with the SDI: the geometric mean of income per person, educational attainment in the population older than age 15 years, and total fertility rate. FINDINGS: The highest globally observed HALE at birth for both women and men was in Singapore, at 75·2 years (95% uncertainty interval 71·9-78·6) for females and 72·0 years (68·8-75·1) for males. The lowest for females was in the Central African Republic (45·6 years [42·0-49·5]) and for males was in Lesotho (41·5 years [39·0-44·0]). From 1990 to 2016, global HALE increased by an average of 6·24 years (5·97-6·48) for both sexes combined. Global HALE increased by 6·04 years (5·74-6·27) for males and 6·49 years (6·08-6·77) for females, whereas HALE at age 65 years increased by 1·78 years (1·61-1·93) for males and 1·96 years (1·69-2·13) for females. Total global DALYs remained largely unchanged from 1990 to 2016 (-2·3% [-5·9 to 0·9]), with decreases in communicable, maternal, neonatal, and nutritional (CMNN) disease DALYs offset by increased DALYs due to non-communicable diseases (NCDs). The exemplars, calculated as the five lowest ratios of observed to expected age-standardised DALY rates in 2016, were Nicaragua, Costa Rica, the Maldives, Peru, and Israel. The leading three causes of DALYs globally were ischaemic heart disease, cerebrovascular disease, and lower respiratory infections, comprising 16·1% of all DALYs. Total DALYs and age-standardised DALY rates due to most CMNN causes decreased from 1990 to 2016. Conversely, the total DALY burden rose for most NCDs; however, age-standardised DALY rates due to NCDs declined globally. INTERPRETATION: At a global level, DALYs and HALE continue to show improvements. At the same time, we observe that many populations are facing growing functional health loss. Rising SDI was associated with increases in cumulative years of life lived with disability and decreases in CMNN DALYs offset by increased NCD DALYs. Relative compression of morbidity highlights the importance of continued health interventions, which has changed in most locations in pace with the gross domestic product per person, education, and family planning. The analysis of DALYs and HALE and their relationship to SDI represents a robust framework with which to benchmark location-specific health performance. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform health policies, health system improvement initiatives, targeted prevention efforts, and development assistance for health, including financial and research investments for all countries, regardless of their level of sociodemographic development. The presence of countries that substantially outperform others suggests the need for increased scrutiny for proven examples of best practices, which can help to extend gains, whereas the presence of underperforming countries suggests the need for devotion of extra attention to health systems that need more robust support. FUNDING: Bill & Melinda Gates Foundation

Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015.

BACKGROUND: Healthy life expectancy (HALE) and disability-adjusted life-years (DALYs) provide summary measures of health across geographies and time that can inform assessments of epidemiological patterns and health system performance, help to prioritise investments in research and development, and monitor progress toward the Sustainable Development Goals (SDGs). We aimed to provide updated HALE and DALYs for geographies worldwide and evaluate how disease burden changes with development. METHODS: We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2015. We calculated DALYs by summing years of life lost (YLLs) and years of life lived with disability (YLDs) for each geography, age group, sex, and year. We estimated HALE using the Sullivan method, which draws from age-specific death rates and YLDs per capita. We then assessed how observed levels of DALYs and HALE differed from expected trends calculated with the Socio-demographic Index (SDI), a composite indicator constructed from measures of income per capita, average years of schooling, and total fertility rate. FINDINGS: Total global DALYs remained largely unchanged from 1990 to 2015, with decreases in communicable, neonatal, maternal, and nutritional (Group 1) disease DALYs offset by increased DALYs due to non-communicable diseases (NCDs). Much of this epidemiological transition was caused by changes in population growth and ageing, but it was accelerated by widespread improvements in SDI that also correlated strongly with the increasing importance of NCDs. Both total DALYs and age-standardised DALY rates due to most Group 1 causes significantly decreased by 2015, and although total burden climbed for the majority of NCDs, age-standardised DALY rates due to NCDs declined. Nonetheless, age-standardised DALY rates due to several high-burden NCDs (including osteoarthritis, drug use disorders, depression, diabetes, congenital birth defects, and skin, oral, and sense organ diseases) either increased or remained unchanged, leading to increases in their relative ranking in many geographies. From 2005 to 2015, HALE at birth increased by an average of 2·9 years (95% uncertainty interval 2·9-3·0) for men and 3·5 years (3·4-3·7) for women, while HALE at age 65 years improved by 0·85 years (0·78-0·92) and 1·2 years (1·1-1·3), respectively. Rising SDI was associated with consistently higher HALE and a somewhat smaller proportion of life spent with functional health loss; however, rising SDI was related to increases in total disability. Many countries and territories in central America and eastern sub-Saharan Africa had increasingly lower rates of disease burden than expected given their SDI. At the same time, a subset of geographies recorded a growing gap between observed and expected levels of DALYs, a trend driven mainly by rising burden due to war, interpersonal violence, and various NCDs. INTERPRETATION: Health is improving globally, but this means more populations are spending more time with functional health loss, an absolute expansion of morbidity. The proportion of life spent in ill health decreases somewhat with increasing SDI, a relative compression of morbidity, which supports continued efforts to elevate personal income, improve education, and limit fertility. Our analysis of DALYs and HALE and their relationship to SDI represents a robust framework on which to benchmark geography-specific health performance and SDG progress. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform financial and research investments, prevention efforts, health policies, and health system improvement initiatives for all countries along the development continuum. FUNDING: Bill & Melinda Gates Foundation