Análise comparativa de dois índices de poluição agrícola no Sistema Aquífero dos Gabros de Beja, sector da margem esquerda do Rio Guadiana

A poluição das águas subterrâneas por nitratos de origem agrícola está relacionada com a vulnerabilidade dos sistemas aquíferos e com as práticas de gestão e fertilização com compostos azotados. O presente estudo aborda o risco de poluição do Sistema Aquífero dos Gabros de Beja, a partir de uma abordagem multidisciplinar do sector de Serpa-Brinches, com base na aplicação de índices empíricos e de mapas de isoprobabilidade da ocorrência de nitratos exceder 50 mg/l no período de 1997 a 2000. Os resultados obtidos evidenciam uma boa correlação entre as áreas predominantemente agrícolas e as classes mais elevadas dos índices analisados, que são concordantes com as áreas de maior probabilidade de ocorrência de nitratos. Este estudo aponta para a necessidade urgente de aplicação do Código de Boas Práticas Agrícolas no sentido de cumprir as orientações da Directiva 91/676/CE e da Directiva Quadro da Água

Fluorescence properties of a potential antitumoral benzothieno[3,2-b]pyrrole in solution and lipid membranes

Fluorescence properties of the antitumoral methyl 3-(benzo[b]thien-2-yl)-benzothieno[3,2-b]pyrrole-2-carboxylate (BTP) were studied in solution and in lipid bilayers of dipalmitoyl phosphatidylcholine (DPPC), dioleoyl phosphatidylethanolamine (DOPE) and egg yolk phosphatidylcholine (Egg-PC). BTP presents good fluorescence quantum yields in all solvents studied (0.20 ≤ ΦF ≤ 0.32) and a bathochromic shift in polar solvents. The results indicate an ICT character of the excited state, with an estimated dipole moment of μe = 7.38 D. Fluorescence (steady-state) anisotropy measurements of BTP incorporated in lipid membranes of DPPC, DOPE and Egg-PC indicate that this compound is deeply located in the lipid bilayer, feeling the difference between the rigid gel phase and fluid phases. BTP inhibits the growth of three human tumour cell lines, MCF-7 (breast adenocarcinoma), SF-268 (glioma) and NCI-H460 (non-small cell lung cancer), being significantly more potent against the NCI-H460 tumour cells.European Communitarian Fund (FEDER)Fundação para a Ciência e a Tecnologia (FCT) – projecto SeARCH (ref. REEQ/443/EEI/2005), bolsa SFRH/BPD/24548/2005, projecto PTDC/QUI/81238/200

Production of photocatalytic road pavements using TiO2 nanoparticles

posterMan’s activity and mismanagement of resources conducted to dangerous levels of pollution in water, air and earth and to incalculable deficiencies, harmful to the physical and social health of mankind. Industrial activities, heating systems and road traffic are the main responsibles for the emission of pollutant gases such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). As so, its harmful impacts are observed far beyond large cities and jam-packed streets. It is important to refer that the health costs related only with road traffic air pollution represents 0.9%-2.7% of the gross domestic product (GDP) in France, for example. Under this context, the combination of nanostructured titanium dioxide (TiO2) and bituminous formulations represents a tool, with considerable degree of innovation, towards the reduction of environmental impacts. In this work, conventional hot mix asphalt (HMA) was produced with standard materials to play the role of a control sample. Afterwards, an aqueous solution of TiO2 nanoparticles was sprayed over sample’s surface. By another hand, a HMA samples was also modified through the volume incorporation of small quantities of TiO2 nanoparticles and recycled glass cullets. It is expected that the inclusion of glass in the asphalt formulations should promote an in-depth conduction and entrapment of light , thus enhancing the photocatalytic performance of this samples. Scanning Electron Microscopy (SEM) analysis were conducted in order to infer about the morphology of the modified HMA samples and the surface as well as the in-depth dispersion of TiO2 nanoparticles and recycled glass cullets. The produced samples were also subjected to wearing tests using the tire-road contact method. Before and after the wearing process, the photocatalytic efficiency was evaluated via the decomposition rate of an aqueous solution of Methylene Blue (MB) under UV light irradiation

Synthesis of fluorescent heteroaromatic compounds using dehydroamino acids as building blocks, studies of DNA and biomembranes interactions : evaluation of antiproliferative effects on tumor cell lines

Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) and FEDER to financial support through the research centres, the research project POCI/59407/2004 and pos-Doc grants attributed to A.S.Abreu (SFRH/BPD/24548/2005) and to L.V.-S. (SFRH/BPD/29112/2006)

Castanea sativa mill. flowers as potential chemopreventive agent against rat prostate cancer model

Introduction: Prostate cancer is one of the most common cancer among men, having a huge impact in their health [1]. This work aimed to evaluate the influence of a decoction extract obtained from C. sativa flowers (CF) on chemically and hormonally induced rat prostate cancer animal model. Material & Methods: All the animal experiments were approved by the Institutional Animals Ethics Committee and by Portuguese national authorities (DGAV no 021326). Forty male Wistar Unilever rats were randomly divided into four groups: control group (n=10), induced group (n=15), CF control group (n=5) and CF induced group (n=10). Animals from induced groups received a multistep induction protocol, which consisted of sequential administration of flutamide, testosterone propionate, the carcinogenic agent MNU and crystalline testosterone. The CF extract, rich in ellagitannins especially trigalloy-HHDP- glucose, was administered in the drinking water (3 mg/animal/day) for 49 weeks. Animals were sacrificed at 61 weeks of age and organs were collected, weighed and processed for light microscopy. Data were analysed using SPSS and GraphPad Prism software. Results: There were no significant differences in relative mean liver weight among groups exposed and not exposed to the CF extract and no animals developed severe hepatic changes. Animals from CF induced group developed less prostatic intraepithelial neoplasia than induced group. Also, animals exposed to the CF extract did not present areas of inflammation of the dorsolateral prostate lobe greater than 50% unlike the groups not exposed (p<0.05). The administration of CF in induced animals was able to decrease the activity of CAT and GST by 36% and 20%, respectively (p<0.05). Conclusions: These results suggest that CF extract was well tolerate by the animals and did not cause severe hepatic and renal toxicity. C. sativa flowers extract may be used as chemopreventive agent against prostate cancer and seems to have an antioxidant role

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

Toxicological and anti-tumor effects of a linden extract (Tilia platyphyllos Scop.) in a HPV16-transgenic mouse model

Tilia platyphyllos Scop. is a popular broad-leaved tree, native to Central and Southern Europe. Hydroethanolic extracts rich in phenolic compounds obtained from T. platyphyllos Scop. have shown in vitro antioxidant, anti-inflammatory and antitumor properties. The aim of this work was to evaluate the therapeutic properties of a hydroethanolic extract obtained from T. platyphyllos in HPV16-transgenic mice. The animals were divided into eight groups according to their sex and phenotype. Four groups of female: HPV+ exposed to linden (HPV linden; n = 6), HPV+ (HPV water; n = 4), HPV- exposed to linden (WT linden; n = 5) and HPV- (WT water; n = 4) and four groups of male: HPV+ exposed to linden (HPV linden; n = 5), HPV+ (HPV water; n = 5), HPV- exposed to linden (WT linden; n = 5) and HPV- (WT water; n = 7). The linden (Tilia platyphyllos Scop.) extract was orally administered at a dose of 4.5 mg/10 mL per animal (dissolved in water) and changed daily for 33 days. The hydroethanolic extract of T. platyphyllos consisted of protocatechuic acid and (-)-epicatechin as the most abundant phenolic acid and flavonoid, respectively, and was found to be stable during the studied period. In two male groups a significant positive weight gain was observed but without association with the linden extract. Histological, biochemical, and oxidative stress analyses for the evaluation of kidney and liver damage support the hypothesis that the linden extract is safe and well-tolerated under the present experimental conditions. Skin histopathology does not demonstrate the chemopreventive effect of the linden extract against HPV16-induced lesions. The linden extract has revealed a favourable toxicological profile; however, additional studies are required to determine the chemopreventive potential of the linden extract. This journal isThis work was supported by the project IBERPHENOL, project number 0377_IBERPHENOL_6_E; Interact R&D project, operation number NORTE-01-0145-FEDER-000017, National Funds by FCT – Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020 (CITAB), and project UIDB/ CVT/00772/2020 (CECAV) and the post-graduation grant SFRH/ BD/136747/2018 and 2020.04789.BD; the authors are also grateful to FCT, Portugal and FEDER under programme PT2020 for financial support to CIMO (UIDB/00690/2020) and L. Barros acknowledges the national funding by FCT, P. I., through the institutional scientific employment program-contract. The authors would like to thank Cantinho das Aromáticas organic farmers from Vila Nova de Gaia (Portugal) for providing the samples. This work was financially supported by: Base Funding - UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE - funded by national funds through the FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio

Dioctadecyldimethylammonium:monoolein nanocarriers for efficient in vitro gene silencing

This study describes a novel liposomal formulation for siRNA delivery, based on the mixture of the neutral lipid monoolein (MO) and cationic lipids of the dioctadecyldimethylammonium (DODA) family. The cationic lipids dioctadecyldimethylammonium bromide (DODAB) and chloride (DODAC) were compared in order to identify which one will most efficiently induce gene silencing. MO has a fluidizing effect on DODAC and DODAB liposomes, although it was more homogeneously distributed in DODAC bilayers. All MO-based liposomal formulations were able to efficiently encapsulate siRNA. Stable lipoplexes of small size (100-160 nm) with a positive surface charge (>+45 mV) were formed. A more uniform MO incorporation in DODAC:MO may explain an increase of the fusogenic potential of these liposomes. The siRNA-lipoplexes were readily internalized by human nonsmall cell lung carcinoma (H1299) cells, in an energy dependent process. DODAB:MO nanocarriers showed a higher internalization efficiency in comparison to DODAC:MO lipoplexes, and were also more efficient in promoting gene silencing. MO had a similar gene silencing ability as the commonly used helper lipid 1,2-dioleyl-3-phosphatidylethanolamine (DOPE), but with much lower cytotoxicity. Taking in consideration all the results presented, DODAB:MO liposomes are the most promising tested formulation for systemic siRNA delivery.This work was supported by FEDER through POFC - COMPETE and by national funds from FCT through the projects PEst-C/BIA/UI4050/2011 (CBM.A), PEst-C/FIS/UI0607/2011 (CFUM), and PTDC/QUI/69795/2006, while Ana Oliveira holds scholarship SFRH/BD/68588/2010. Eloi Feitosa thanks FAPESP (2011/03566-0) and CNPq (303030/2012-7), and Renata D. Adati thanks FAPESP for scholarship (2011/07414-0). K. Raemdonck is a postdoctoral fellow of the Research Foundation - Flanders (FWO-Vlaanderen). We acknowledge NanoDelivery-I&D em Bionanotecnologia, Lda. for access to their equipment

The opposing transcriptional functions of Sin3a and c-Myc are required to maintain tissue homeostasis.

How the proto-oncogene c-Myc balances the processes of stem-cell self-renewal, proliferation and differentiation in adult tissues is largely unknown. We explored c-Myc's transcriptional roles at the epidermal differentiation complex, a locus essential for skin maturation. Binding of c-Myc can simultaneously recruit (Klf4, Ovol-1) and displace (Cebpa, Mxi1 and Sin3a) specific sets of differentiation-specific transcriptional regulators to epidermal differentiation complex genes. We found that Sin3a causes deacetylation of c-Myc protein to directly repress c-Myc activity. In the absence of Sin3a, genomic recruitment of c-Myc to the epidermal differentiation complex is enhanced, and re-activation of c-Myc-target genes drives aberrant epidermal proliferation and differentiation. Simultaneous deletion of c-Myc and Sin3a reverts the skin phenotype to normal. Our results identify how the balance of two transcriptional key regulators can maintain tissue homeostasis through a negative feedback loop