224 research outputs found

    Hydrogen Peroxide in Adaptation

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    NICHO E ENDEMISMO EM AMBIENTES ENTREMARÉS RECIFAIS: UMA ABORDAGEM UTILIZANDO ISÓTOPOS ESTÁVEIS

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    Embora o conceito de nicho ecológico possa variar de acordo com o campo da ecologia estudado, sua essência constitui em entender a forma que organismos vivem sob distintas condições bióticas e abióticas. Nesta tese eu procuro, por meio de isótopos estáveis e baseado numa abordagem Eltoniana, compreender a forma que organismos marinhos coexistem em recifes entremarés, embora muitos aspectos e análises conduzidas, bem como o próprio alcance da técnica de isótopos estáveis, permeiem através de ideias Grinelliana e Hutchisoniana. Os estudos foram conduzidos em seis ambientes entremarés insulares e costeiros da Província Brasileira: Atol das Rocas, Fernando de Noronha e Trindade representando ilhas oceânicas e Salinópolis (Pará), Jericoacoara (Ceará) e Anchieta (Espírito Santo) representando ambientes costeiros. Os capítulos da tese revelam progressivamente a importância e organização ecológica destes ambientes. Assim, o primeiro capítulo faz uma breve introdução do tema da tese e seus capítulos subsequentes seguido pelo segundo que destaca a elevada taxa de endemismo de peixes nos recifes entremarés de ilhas, ressaltando a fragilidade deste ambiente e de suas espécies endêmicas frente a impactos pontuais e crônicos. O terceiro capítulo consiste em um estudo da estrutura das comunidades de peixes dos seis sítios revelando que todas as comunidades foram dominadas em composição e número por espécies de pequeno porte e adaptadas à vida no entremarés. Em ilhas, espécies endêmicas foram as mais representativas, sendo responsáveis pela estruturação das comunidades e sua distribuição esteve correlata a diferentes variáveis estruturais. O quarto capítulo faz uso de análises isotópicas de 13C e 15N para evidenciar, através de modelagens, que as teias tróficas nas ilhas são mais longas e complexas, e que as espécies críptobênticas do entremarés, incluindo espécies endêmicas, são as mais vulneráveis à pressões de competição intra e interespecíficas. O quinto capítulo é voltado ao estudo dos impactos esperados em ilhas após invasão por uma espécie exótica. Para tal, usou-se dados de densidade e assinaturas isotópicas na zona costeira para simular a presença do invasor nas ilhas. Embora grande parte das espécies demonstraram ser fracas competidoras frente a uma potencial invasão, a vulnerabilidade das espécies endêmicas à presença da espécie invasora chama a atenção devido às baixas capacidades de competição e pelo restritos territórios de vida. O sexto capítulo reporta a morte por dessecação de espécies residentes e não-residentes do entremarés, ressaltando as rigorosas pressões abióticas deste ambiente sobre sua fauna. Por fim, o sétimo capítulo é uma nota técnica apresentando relações peso-comprimento e comprimento-comprimento de peixes das ilhas estudadas, inclusive de espécies endêmicas da Província Brasileira, publicado afim de contribuir com futuros trabalhos na elaboração de estimativas precisas de biomassa. Em suma, o nicho em ambientes entremarés recifais das ilhas oceânicas brasileiras revela, pela primeira vez, comunidades com elevados níveis de diversidade trófica e de seus recursos basais, ao mesmo tempo frágeis no que diz respeito ao seu elevado endemismo, à vulnerabilidade competitiva de suas espécies endêmicas, à presença de espécies invasoras e ao risco de desaparecimento frente à subida do nível do mar. Palavras-chave: Nicho isotópico, poças de marés, SIBER, Omobranchus punctatu

    Supplementing nursery pig feed with seaweed extracts increases final body weight of pigs

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    Probiotics have been used as an alternative method to antibiotic treatment. In this study, we evaluated the effect of seaweed extracts, commercially named OceanFeed Swine® (OFS), on body weight, average daily weight gain (ADG) and feed efficiency (FE) in nursery and fattening pigs of terminal lines. The study was conducted with 1809 piglets from weaning age until the end of the fattening phase on a commercial farm, divided into two groups (control and OFS; 905 and 904 pigs, respectively). Three replicates were made during the 6 weeks of production. Food was elaborated in the same productive unit and was given to the animals in the form of flour. OceanFeed Swine® (5 g/kg of diet) was added to the diet of the OFS groups during the nursery period, from 21 to 55 days of age. The faecal microbial population was evaluated at 35 and 60 days of life. In this paper, we observed a positive effect of administering OceanFeed Swine® on the production parameters analysed in the fattening phase, showing an improvement of 26 g in ADG and FE of 0.07. It can be concluded that the use of OceanFeed Swine® in the diets of the piglets, aged between 21 to 55 days old, improves FE (Control 2.36, OFS 2.29) and ADG (control 0.798 kg, OFS 0.824 kg). Moreover, its use exhibited an increase in the slaughter weight, a reduction of E coli CFU, and an increase in Lactobacillus sp. in fattening animals. All these improvements have a major positive economic impact per pig at time of slaughter

    Distribution of lower urinary tract symptoms (LUTS) in adult women

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    OBJECTIVE: To determine the distribution of lower urinary tract symptoms in adult women and the frequency with which the women consulted a health care provider for their symptoms. DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: Community Health Center of Aga Khan University Hospital from November 1st to 30th, 2002. SUBJECTS AND METHODS: A trained interviewer administered a structured questionnaire to women patients or attendants aged 18 years and older coming to the center. RESULTS: Fifty-two percent of the study subjects reported having at least one or more urinary complaints in the past. Stress incontinence was the highest reported complaint (38.4%) followed by burning (34.4%), frequency (26%), painful micturition (20.4%), urge incontinence (18.8 %), incomplete emptying of bladder (14.4%), dribbling (12.4%) and poor stream (8.4%). Forty-three percent of the women with LUTS never consulted a health care provider for their problem.CONCLUSION: Although the distribution of LUTS among females was found to be high, the patients did not consider it important enough to consult a health care provider. There is a need to create awareness among females regarding LUTS and the need to consult a health care provider for their problems

    Ahorro energético en riego por aspersión. Pruebas de nuevos aspersores en banco automático con viento

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    El consumo energético en regadío es directamente proporcional a los valores objetivos de presión de una red colectiva de riego presurizada. El sistema de riego en parcela que más condiciona esta presión objetivo es el riego por aspersión. En este trabajo se ha analizado el comportamiento de los aspersores más utilizados en España en condiciones normales de funcionamiento frente a condiciones de presiones más bajas. Para ello se utilizó un banco de ensayo automático con viento y otro en condiciones confinadas sin viento. Se analizaron los aspersores en múltiples condiciones de trabajo, priorizando en el estudio la variable presión. Para ello se contempló un rango de presiones de 1,5 bar a 3.5 bar y con dos regímenes de viento: sin viento y con viento moderado. Como resultados del estudio se ofrece un análisis global de los datos obtenidos, que justifican la posibilidad de reducir la presión en riego por aspersión Además, se profundiza en resultados concretos para la reducción de la presión en el marco de riego de doce por quince metros

    A New Kind of Quinonic-Antibiotic Useful Against Multidrug-Resistant S. aureus and E. faecium Infections

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    Indexación: Scopus.A rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and reducing the therapeutic arsenal available for treatment of infectious diseases. In the present study, we developed a new class of compounds with antibacterial activity obtained by a simple, two step synthesis and screened the products for in vitro antibacterial activity against ATCC® strains using the broth microdilution method. The compounds exhibited minimum inhibitory concentrations (MIC) of 1⁻32 μg/mL against Gram-positive ATCC® strains. The structure⁻activity relationship indicated that the thiophenol ring is essential for antibacterial activity and the substituents on the thiophenol ring module, for antibacterial activity. The most promising compounds detected by screening were tested against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) clinical isolates. We found remarkable activity against VREF for compounds 7 and 16, were the MIC50/90 were 2/4 µg/mL and 4/4 µg/mL, respectively, while for vancomycin the MIC50/90 was 256/512 µg/mL. Neither compound affected cell viability in any of the mammalian cell lines at any of the concentrations tested. These in vitro data show that compounds 7 and 16 have an interesting potential to be developed as new antibacterial drugs against infections caused by VREF.https://www.mdpi.com/1420-3049/23/7/177

    Epigenetic Silencing of Tumor Suppressor miR-124 Directly Supports STAT3 Activation in Cutaneous T-Cell Lymphoma

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    Increasing evidence supports a potential role for STAT3 as a tumor driver in cutaneous T-cell lymphomas (CTCL). The mechanisms leading to STAT3 activation are not fully understood; however, we recently found that miR-124, a known STAT3 regulator, is robustly silenced in MF tumor-stage and CTCL cells. OBJECTIVE: We studied here whether deregulation of miR-124 contributes to STAT3 pathway activation in CTCL. METHODS: We measured the effect of ectopic mir-124 expression in active phosphorylated STAT3 (p-STAT3) levels and evaluated the transcriptional impact of miR-124-dependent STAT3 pathway regulation by expression microarray analysis. RESULTS: We found that ectopic expression of miR-124 results in massive downregulation of activated STAT3 in different CTCL lines, which resulted in a significant alteration of genetic signatures related with gene transcription and proliferation such as MYC and E2F. CONCLUSIONS: Our study highlights the importance of the miR-124/STAT3 axis in CTCL and demonstrates that the STAT3 pathway is regulated through epigenetic mechanisms in these cells. Since deregulated STAT3 signaling has a major impact on CTCL initiation and progression, a better understanding of the molecular basis of the miR-124/STAT3 axis may provide useful information for future personalized therapies

    WNT ligands contribute to the immune response during septic shock and amplify endotoxemia-driven inflammation in mice

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    Improved understanding of the molecular mechanisms underlying dysregulated inflammatory responses in severe infection and septic shock is urgently needed to improve patient management and identify new therapeutic opportunities. The WNT signaling pathway has been implicated as a novel constituent of the immune response to infection, but its contribution to the host response in septic shock is unknown. Although individual WNT proteins have been ascribed pro- or anti-inflammatory functions, their concerted contributions to inflammation in vivo remain to be clearly defined. Here we report differential expression of multiple WNT ligands in whole blood of patients with septic shock and reveal significant correlations with inflammatory cytokines. Systemic challenge of mice with lipopolysaccharide (LPS) similarly elicited differential expression of multiple WNT ligands with correlations between WNT and cytokine expression that partially overlap with the findings in human blood. Molecular regulators of WNT expression during microbial encounter in vivo are largely unexplored. Analyses in gene-deficient mice revealed differential contributions of Toll-like receptor signaling adaptors, a positive role for tumor necrosis factor, but a negative regulatory role for interleukin (IL)-12/23p40 in the LPS-induced expression of Wnt5b, Wnt10a, Wnt10b, and Wnt11. Pharmacologic targeting of bottlenecks of the WNT network, WNT acylation and β-catenin activity, diminished IL-6, tumor necrosis factor, and IL-12/23p40 in serum of LPS-challenged mice and cultured splenocytes, whereas IL-10 production remained largely unaffected. Taken together, our data support the conclusion that the concerted action of WNT proteins during severe infection and septic shock promotes inflammation, and that this is, at least in part, mediated by WNT/β-catenin signaling
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