Transport in the blood of an anti-tumor water-soluble rutheniun cyclopentadienyl complex: a fluorescence study on albumin binding

Dissertação de mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014

Anti-vibrio potentials of acetone and aqueous leaf extracts of Ocimum gratissimum (Linn)

Purpose: To evaluate the anti-vibrio potentials of acetone and aqueous leaf extracts of Ocimum gratissimum and determine its relevance in the treatment of vibrios infection. Methods: The agar-well diffusion method was used for screening the extracts for their anti-vibrio activity. Broth micro-dilution assay was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts. Time-kill assay was used to assess bactericidal and/or bacteriostatic activity. Results: The acetone extract showed activity against 47.5 % (19/40) of the test bacteria, while the aqueous extract had activity against 30 % (12/40). MIC and MBC values range for the acetone extract were 0.625 – 5.0 mg/mL and 2.5 – 10 mg/mL respectively. The range of MIC exhibited by the antibiotic (gentamicin) against the vibrios is 0.002 mg/mL and >0.256 mg/mL. Significant reduction in the bacterial density was at 2 × MIC after a 4 h interaction period, while bacterial density after 6 and 8 h interactions with extract was highly bactericidal. Growth inhibition and efficacy of the crude acetone extract were observed to be both concentration- and time-dependent. Conclusion: The bacteriostatic and bactericidal activities observed for Ocimum gratissimum leaf suggest that the plant is a potential source of bioactive components that may be effective in the treatment of vibrios infections.

Anti-biofilm and antimicrobial activity of Mentha pulegium L essential oil against multidrug-resistant Acinetobacter baumannii

Purpose: To investigate the antimicrobial and anti-biofilm activities of essential oil from Mentha pulegium L. (EOMP) on multi-drug resistant (MDR) isolates of A. baumannii , as well as its phytochemical composition, antioxidant properties and cytotoxic activity. Methods: The phytochemical composition of EOMP was analyzed by gas chromatography, while its antimicrobial activities were determined by disc diffusion and broth micro-dilution methods. Minimal biofilm inhibition concentration (MBIC) and minimal biofilm eradication concentration (MBEC) tests were used for assessment of its anti-biofilm properties. Viability in the biofilm was studied using 2,3-bis (2- methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay, while colorimetric assay was used to assess its cytotoxicity on L929 cells. Results: D-isomenthone, pulegone, isopulegone, menthol and piperitenone were the major components of the plant extract. EOMP produced > 22 mm inhibition zone for the isolates, with minimum inhibitory concentration (MIC) and MBIC of 0.6 - 2.5 and 0.6 - 1.25 μL/mL, respectively, while MBEC was ≥ 10 μL/msL. EOMP damaged biofilm structures formed by A. baumannii strains at MIC by 26 – 91 %. Conclusion: These results suggest that EOMP contains agents that may be useful in the development of new drugs against A. baumannii infections.

Rigidez ou flexibilidade governamental? Discursos anti-corrupção e pró-eficiência sobre contratações com orçamento sigilogo

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciência Política, Programa de Pós-Graduação em Ciência Política, 2016.

Harnessing bacterial signals for suppression of biofilm formation in the nosocomial fungal pathogen Aspergillus fumigatus

Faced with the continued emergence of antibiotic resistance to all known classes of antibiotics, a paradigm shift in approaches toward antifungal therapeutics is required. Well characterized in a broad spectrum of bacterial and fungal pathogens, biofilms are a key factor in limiting the effectiveness of conventional antibiotics. Therefore, therapeutics such as small molecules that prevent or disrupt biofilm formation would render pathogens susceptible to clearance by existing drugs. This is the first report describing the effect of the Pseudomonas aeruginosa alkylhydroxyquinolone interkingdom signal molecules 2-heptyl-3-hydroxy-4-quinolone and 2-heptyl-4-quinolone on biofilm formation in the important fungal pathogen Aspergillus fumigatus. Decoration of the anthranilate ring on the quinolone framework resulted in significant changes in the capacity of these chemical messages to suppress biofilm formation. Addition of methoxy or methyl groups at the C5–C7 positions led to retention of anti-biofilm activity, in some cases dependent on the alkyl chain length at position C2. In contrast, halogenation at either the C3 or C6 positions led to loss of activity, with one notable exception. Microscopic staining provided key insights into the structural impact of the parent and modified molecules, identifying lead compounds for further development.

Eficacia de terapias biológicas de tipo anti-angiogénico en el cáncer colorrectal metastásico revisión sistemática de la literatura

Introducción: El cáncer colorrectal (CCR) se encuentra entre los 5 tipos de cáncer con mayor incidencia a nivel mundial. Alrededor del 20% de los casos son diagnosticados en estadios metastásico, donde el tratamiento inicialmente era quimioterapia con una supervivencia global a 5 años de 12 a 14 meses. Es así que se investiga el papel de la angiogénesis tumoral, orientado al desarrollo de terapias, implementando su uso en estadios avanzados. Metodología: Se realizó una búsqueda sistemática en las bases de datos Embase, PubMed, SciELO y LILIACS con términos estandarizados a través de la herramienta MeSH y DECS bajo los lineamientos establecidos en las guías de revisiones sistemáticas y meta-análisis (Manual Cochrane). Se tomaron estudios clínicos aleatorizados controlados con pacientes con CCR metastásico, que hayan recibido quimioterapia sola o combinada con terapias antiangiogénicas, publicados en inglés y español entre el 2003 y 2013. Resultados: 6 artículos cumplieron con criterios de inclusión. Estos reportaron 15.8 meses en promedio de supervivencia global en el tratamiento de quimioterapia asociada a terapias biológicas frente a 14.4 meses con solo quimioterapia. Los eventos adversos de tipo vascular aumentaron más en el grupo de antiangiogénicos, reportando muertes debidas a perforaciones intestinales. Conclusiones: Los regímenes de quimioterapia asociadas a terapias antiangiogénicas brindan una mayor supervivencia global y libre de progresión, al igual que mayor número de tasas de respuesta. Son terapias con eventos adversos importantes pero que deberá seleccionarse bien al paciente para disminuir su riesgo de eventos. Palabras claves: Cáncer colorrectal metastásico, terapia anti-angiogénica, quimioterapia en segunda línea, receptor del factor de crecimiento de endotelio vascular, supervivencia global.

Green mitigation strategy for cultural heritage: bacterial potential for biocide production

Several biosurfactants with antagonistic activity are produced by a variety of microorganisms. Lipopeptides (LPPs) produced by some Bacillus strains, including surfactin, fengycin and iturin are synthesized nonribosomally by mega-peptide synthetase (NRPS) units and they are particularly relevant as antifungal agents. Characterisation, identification and evaluation of the potentials of several bacterial isolates were undertaken in order to establish the production of active lipopeptides against biodeteriogenic fungi from heritage assets. Analysis of the iturin operon revealed four open reading frames (ORFs) with the structural organisation of the peptide synthetases. Therefore, this work adopted a molecular procedure to access antifungal potential of LPP production by Bacillus strains in order to exploit the bioactive compounds synthesis as a green natural approach to be applied in biodegraded cultural heritage context. The results reveal that the bacterial strains with higher antifungal potential exhibit the same morphological and biochemical characteristics, belonging to the genera Bacillus. On the other hand, the higher iturinic genetic expression, for Bacillus sp. 3 and Bacillus sp. 4, is in accordance with the culture antifungal spectra. Accordingly, the adopted methodology combining antifungal screening and molecular data is represent a valuable tool for quick identification of iturin-producing strains, constituting an effective approach for confirming the selection of lipopeptides producer strains.

Control of citrus black spot (Guignardia citricarpa) by biological control agents and other alternative products.

2007