An investigation of the Acarine fauna of rehabilitated bauxite mines in the Northern Jarrah Forest

The northern jarrah forest relies on efficient nutrient cycling for its growth and long term sustainability. The decomposition of organic matter and the recycling of nutrients in such ecosystems are facilitated through the interaction of microflora with a myriad of invertebrates. The recolonisation of invertebrate fauna to rehabilitated bauxite mines is thus of critical importance to the long-term success of rehabilitation. This study investigated the soil and litter mite fauna, important components of the invertebrate community well known for their numerical dominance and high biodiversity. A spring sampling of the mite fauna was undertaken, employing standard soil and litter sampling techniques and temperature controlled heat extraction. The effect of time since rehabilitation was investigated in 2, 5, 10 and 20 year old sites, chosen to represent successional-like stages in rehabilitation. A neighbouring forest control site was selected for comparison. Selected environmental variables known to influence mite abundance and diversity were also measured. The abundance and species richness of the mite community in soil and litter increased with age of the rehabilitated site. The litter habitat of the 10 and 20 year old site displayed similar abundances to those of the forest control site. At the Ordinal level, the Astigmata and Prostigmata were most abundant in the younger sites where vegetation was sparse and canopy cover was minimal. The Cryptostigmata were the numerically dominant Order once the litter and canopy cover developed, in total accounting for 70% of all mites sampled. Distinct species-suites were identified for both the soil and litter, which could be related to the age sequence in litter development of rehabilitated sites. This included a \u27generalist\u27 suite that displayed insensitivity to environmental conditions across all sites. An intermediate suite of species that required successional-Iike development of site characteristics, may indicate level of habitat development. A site specific group of species that were restricted to the undisturbed forest site, represent species sensitive to habitat conditions. The study has implications regarding level of taxonomic detail applied, when assessing the success of invertebrate recolonisation in rehabilitated sites. Although mite distribution at the Ordinal level was similar, analysis at the Family and species level revealed clear differences between the rehabilitated sites and the forest control

Preparation of PVP hydrogel nanoparticles using lecithin vesicles

Hydrogels micro, sub-micro and nanoparticles are of great interest for drug encapsulation and delivery or as embolotherapic agents. In this work it is described the preparation of nano and sub-microparticles of pre-formed, high molecular weight and monomer free poly(N-vinyl-2-pyrrolidone) encapsulated inside the core of lecithin vesicles. The hydrogel particles are formed with a very narrow diameter distribution, of about 800 nm, and a moderate swelling ratio, of approximately 10

Macrophage Trafficking as Key Mediator of Adenine-Induced Kidney Injury

Macrophages play a special role in the onset of several diseases, including acute and chronic kidney injuries. in this sense, tubule interstitial nephritis (TIN) represents an underestimated insult, which can be triggered by different stimuli and, in the absence of a proper regulation, can lead to fibrosis deposition. Based on this perception, we evaluated the participation of macrophage recruitment in the development of TIN. Initially, we provided adenine-enriched food to WT and searched for macrophage presence and action in the kidney. Also, a group of animals were depleted of macrophages with the clodronate liposome while receiving adenine-enriched diet. We collected blood and renal tissue from these animals and renal function, inflammation, and fibrosis were evaluated. We observed higher expression of chemokines in the kidneys of adenine-fed mice and a substantial protection when macrophages were depleted. Then, we specifically investigated the role of some key chemokines, CCR5 and CCL3, in this TIN experimental model. Interestingly, CCR5 KO and CCL3 KO animals showed less renal dysfunction and a decreased proinflammatory profile. Furthermore, in those animals, there was less profibrotic signaling. in conclusion, we can suggest that macrophage infiltration is important for the onset of renal injury in the adenine-induced TIN.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto Nacional de Ciencia e Tecnologia de Fluidos Complexos (INCT Complex Fluids)Univ São Paulo, Inst Biomed Sci, Dept Immunol, Lab Transplantat Immunobiol, BR-05508900 São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, Lab Clin & Expt Immunol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04023062 São Paulo, BrazilUniv São Paulo, Inst Chem, Dept Biochem, BR-05508000 São Paulo, BrazilUniv São Paulo, Sch Med Ribeirao Preto, Dept Biochem & Immunol, BR-14049900 Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo, Div Nephrol, Lab Clin & Expt Immunol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04023062 São Paulo, BrazilFAPESP: 2009/54474-8FAPESP: 2012/02270-2FAPESP: 2013/25010-9Web of Scienc

Effect of essential oils from Eucalyptus on the growth of aflatoxigenic species

In Brazil, Eucalyptus species has been cultivated as source of energy and cellulose. They represent the most important cultivated forest in the country. In production areas, the leaves from the trees decay on the soil as green fertilizer. In this study were evaluated pure and blends of essential oils from different species of eucalyptus trees grown in Brazil for antifungal activity against aflatoxigenic species Aspergillus flavus and A. parasiticus. These fungal species can grow and contaminate grains during the storage period under high r.h. conditions, with an eventual production of aflatoxins. Antifungal activity was evaluated by the radial growth measurement of the fungi inoculated on maize meal extract agar basic medium. The eucalyptus oils were evaluated in a contact assay and a fumigant assay using pure and blended oils. Six concentrations of pure and blended oils were evaluated at the following doses: 0, 2, 4, 16, 32 and 84 μL per 20 mL of fungi culture medium. Fungal inocula from conidia suspensions containing 106 spores/mL was inoculated by a needle. Glass Petri dishes were incubated for 9 days at 28°C (± 0.3°C) in the dark. Antifungal activity was observed in all pure and blended oils, in different concentrations of contact and fumigant assay, for both fungi. Eucalyptus stageiriana oil and E. stageiriana + the hybrid E. grandis x E. urophylla oils blend controlled the total fungal growth at the lowest dose (20 μL). Keywords: Essential oil; Eucalyptus spp.; Aspergillus flavus; Aspergillus parasiticus; Antifungal activity

A magnanimidade da teoria: interpretar a ética em teoria da literatura

Tese de doutoramento, Teoria da Literatura, Universidade de Lisboa, Faculdade de Letras, 2003Um dos pressupostos desta tese consiste na ideia segundo a qual o pensamento ético só adquire propriedade conceptual se preliminarmente pudermos definir ‘acção’. Como se procura demonstrar no capítulo I, saber o que é uma acção não se constitui, no entanto, como tarefa que descobre e estabelece propriedades intrínsecas e estáveis, mas como descrição de certas ocorrências, nos termos das pessoas que procuram explicar e descrever acções. Assim, o pensamento ético é algo que se constitui a partir da coerência e racionalidade de certas descrições de acções particulares e não um sistema de regras ou prescrições. Defende-se que a coerência estrutural destas descrições determina não apenas a consideração moral das acções, mas também a possibilidade do conhecimento entre as pessoas e a certeza, mais poética do que epistemológica, da sua existência. Se uma certa estabilidade do texto ético e uma certeza suficiente acerca do conhecimento humano dependem da configuração mais ou menos padronizada das acções humanas e do funcionamento mental, assumem especial relevância cognitiva e ética os casos e fenómenos de irracionalidade na realização de acções e formação de crenças. De facto, como se sugere no capítulo II, estes casos suscitam perplexidades éticas e cognitivas e assinalam o carácter provisório e conceptualmente circunscrito das nossas descrições sobre acções e pessoas, no contexto restrito do pensamento filosófico e ético. Importa por isso considerar outros textos em que a acção se constitui como motivo de estrutura argumentativa e objecto de análise. A consideração da tragédia e, sobretudo, a análise da teorização poética de Aristóteles acerca do texto trágico formam o capítulo III desta tese. A determinação ética da argumentação técnica da Poética é tão relevante para o entendimento da tragédia quanto, para a ética, conduta moral e compreensão da irracionalidade, é de absoluta pertinência uma particular descrição da acção trágica e da peculiaridade de certas actividades interpretativas exigidas não só por esse entendimento trágico de acção, mas por qualquer texto.ABSTRACT - One of the central ideas of this thesis is that ethical thinking acquires conceptual accuracy only when we can define ‘action’. As it is suggested in chapter I, to know what an action is is not, nevertheless, an activity which finds and establishes intrinsic and stable properties, but a description of some phenomena, in the vocabulary of those who seek to explain and to describe actions. Thus, ethical thinking is derived from the coherence and rationality of descriptions of particular actions and is not, therefore, a system of rules and prescriptions. It is argued that the structural coherence of these descriptions determines not only the moral apprehension of actions, but also the possibility of knowledge of persons and the assurance, more poetical than epistemological, of their existence. If a certain stability of the ethical text and a sufficient certainty about human knowledge depend on a more or less standard configuration of human actions and of mental functioning, then irrational episodes and phenomena in action and belief assume a particular cognitive and ethical relevance. As proposed in chapter II, these cases excite some ethical and cognitive perplexities and show the provisional and conceptually circumscribed character of our descriptions of actions and persons, in the strict realm of philosophy and ethics. It is necessary, therefore, to consider other texts in which action is constituted as the cause for the argumentative structure and object of analysis. The consideration of tragedy and, mostly, of the treatment of the tragic text in Aristotle’s Poetics constitutes an important part of this task and is sketched in chapter III. The ethical influence of the technical arguments of the Poetics is therefore relevant to the understanding of tragedy. A particular description of tragic action and of the specificity of interpretative activities is required not only by the understanding of action in tragedy as by the description of ethical patterns of moral behaviour and the comprehension of irrationality in any text.Fundação Calouste Gulbenkian: Bolsa de Curta Duraçã

Peptide:lipid ratio and membrane surface charge determine the mechanism of action of the antimicrobial peptide BP100. Conformational and functional studies

The cecropin-melittin hybrid antimicrobial peptide BP100 (H-KKLFKKILKYL-NH2) is selective for Gram-negative bacteria, negatively charged membranes, and weakly hemolytic. We studied BP100 conformational and functional properties upon interaction with large unilamellar vesicles, LUVs, and giant unilamellar vesicles, GUVs, containing variable proportions of phosphatidylcholine (PC) and negatively charged phosphatidylglycerol (PG). CD and NMR spectra showed that upon binding to PG-containing LUVs BP100 acquires a-helical conformation, the helix spanning residues 3-11. Theoretical analyses indicated that the helix is amphipathic and surface-seeking. CD and dynamic light scattering data evinced peptide and/or vesicle aggregation, modulated by peptide: lipid ratio and PG content. BP100 decreased the absolute value of the zeta potential () of LUVs with low PG contents; for higher PG, binding was analyzed as an ion-exchange process. At high salt, BP100-induced LUVS leakage requires higher peptide concentration, indicating that both electrostatic and hydrophobic interactions contribute to peptide binding. While a gradual release took place at low peptide:lipid ratios, instantaneous loss occurred at high ratios, suggesting vesicle disruption. Optical microscopy of GUVs confirmed BP100-promoted disruption of negatively charged membranes. the mechanism of action of BP100 is determined by both peptide:lipid ratio and negatively charged lipid content While gradual release results from membrane perturbation by a small number of peptide molecules giving rise to changes in acyl chain packing, lipid clustering (leading to membrane defects), and/or membrane thinning, membrane disruption results from a sequence of events large-scale peptide and lipid clustering, giving rise to peptide-lipid patches that eventually would leave the membrane in a carpet-like mechanism. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Institut Nacional de Ciencia e Tecnologia de fluidos complexos (INCTFCx)Nude de Apoio Pesquisa de Fluidos Complexos (NAPFCx)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ São Paulo, Inst Chem, Dept Biochem, BR-05513970 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04044020 São Paulo, BrazilUniv Fed Rio de Janeiro, Inst Med Biochem, Nucl Magnet Resonance Natl Ctr, Rio de Janeiro, BrazilEmbrapa Recursos Genet & Biotecnol, BR-70770917 Brasilia, DF, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04044020 São Paulo, BrazilFAPESP: 2007/50970-5FAPESP: 2013/08166-5Web of Scienc

DODAB and DODAC bilayer-like aggregates in the micromolar surfactant concentration domain

In the millimolar concentration domain (typically 1 mM), dioctadecyldimethylammonium bromide and chloride (DODAX, X representing Br- or Cl- counterions) molecules assemble in water as large unilamellar vesicles. Differential scanning calorimetry (DSC) is a suitable technique to obtain the melting temperature (Tm) characteristic of surfactant bilayers, while fluorescence spectroscopy detects formation of surfactant aggregates, like bilayers. These two techniques were combined to investigate the assemble of DODAX molecules at micromolar concentrations, from 10 to 100 micromolar. At 1 mM surfactant, Tm ~ 45 ºC and 49 oC, respectively for DODAB and DODAC. DSC and fluorescence of Nile Red were used to show the formation of DODAX aggregates, at the surfactant concentration as low as 10 micromolar, whose Tm decreases monotonically with increasing DODAX concentration to attain the value for the ordinary vesicles. The data indicate that these aggregates are organized as bilayer-like structures.Fundação para a Ciência e a Tecnologia (FCT

Spectroscopic studies as a toolbox for biophysical and chemical characterization of lipid-based nanotherapeutics

The goal of this study is to provide tools to minimize trial-and-error in the development of novel lipid-based nanotherapeutics, in favor of a rational design process. For this purpose, we present case-study examples of biophysical assays that help addressing issues of lipid-based nanotherapeutics' profiling and assist in the design of lipid nanocarriers for therapeutic usage. The assays presented are rooted in spectroscopic methods (steady-state and time-resolved fluorescence; UV-Vis derivative spectroscopy; fluorescence anisotropy and fluorescence lifetime image microscopy) and allow accessing physical-chemical interactions between drugs and lipid nanocarriers, as well as studying interactions between lipid-based nanotherapeutics and membranes and/or proteins, as this is a key factor in predicting their therapeutic and off target effects. Derivative spectroscopy revealed Naproxen's high distribution (LogD ≈ 3) in different lipid-based nanocarriers (micelles and unilamellar or multilamellar vesicles) confirming the adequacy of such systems for encapsulating this anti-inflammatory drug. Fluorescence quenching studies revealed that the anti-inflammatory drugs Acemetacin and Indomethacin can reach an inner location at the lipid nanocarrier while being anchored with its carboxylic moiety at the polar headgroup. The least observed quenching effect suggested that Tolmetin is probably located at the polar headgroup region of the lipid nanocarriers and this superficial location may translate in a fast drug release from the nanocarriers. Fluorescent anisotropy measurements indicated that the drugs deeply buried within the lipid nanocarrier where the ones that had a greater fluidizing effect which can also translate in a faster drug release. The drug binding strength to serum albumin was also compared for a free drug (Clonixin) or for the same drug after encapsulation in a lipid nanocarrier DSPC:DODAP (2:1). Under both conditions there is a strong binding to serum albumin, at one binding site, suggesting the need to produce a stealth nanosystem. Finally the cellular uptake of lipid nanocarriers loaded with Daunorubicin was investigated in cancer cells using fluorescence lifetime imaging microscopy. From the images obtained it was possible to conclude that even at short incubation times (15 min) there was a distribution of the drug in the cytoplasm, whereas for longer incubation periods (4 h) the drug has reached the nucleus.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and in the ambit of the project IF/00498/2012