Ramos, S, Almeida RM, Moura JJ, Aureliano M.
2010.
Implications of oxidovanadium(IV) binding to actin, Jun. J Inorg Biochem. 105:777-83., Number 6
AbstractOxidovanadium(IV), a cationic species (VO(2+)) of vanadium(IV), binds to several proteins, including actin. Upon titration with oxidovanadium(IV), approximately 100% quenching of the intrinsic fluorescence of monomeric actin purified from rabbit skeletal muscle (G-actin) was observed, with a V(50) of 131 muM, whereas for the polymerized form of actin (F-actin) 75% of quenching was obtained and a V(50) value of 320 muM. Stern-Volmer plots were used to estimate an oxidovanadium(IV)-actin dissociation constant, with K(d) of 8.2 muM and 64.1 muM VOSO(4), for G-actin and F-actin, respectively. These studies reveal the presence of a high affinity binding site for oxidovanadium(IV) in actin, producing local conformational changes near the tryptophans most accessible to water in the three-dimensional structure of actin. The actin conformational changes, also confirmed by (1)H NMR, are accompanied by changes in G-actin hydrophobic surface, but not in F-actin. The (1)H NMR spectra of G-actin treated with oxidovanadium(IV) clearly indicates changes in the resonances ascribed to methyl group and aliphatic regions as well as to aromatics and peptide-bond amide region. In parallel, it was verified that oxidovanadium(IV) prevents the G-actin polymerization into F-actin. In the 0-200 muM range, VOSO(4) inhibits 40% of the extent of polymerization with an IC(50) of 15.1 muM, whereas 500 muM VOSO(4) totally suppresses actin polymerization. The data strongly suggest that oxidovanadium(IV) binds to actin at specific binding sites preventing actin polymerization. By affecting actin structure and function, oxidovanadium(IV) might be responsible for many cellular effects described for vanadium.
de Martins, {RFP}, Fortunato {EMC}, Baptista {PMRV}, Águas {HMB}.
2010.
Inkjet printed and {"}doctor blade{"} TiO2 photodetectors for DNA biosensors, jan. Biosensors & Bioelectronics. 25:1229–1234., Number 5: Elsevier
AbstractA dye sensitized TiO2 photodetector has been integrated with a DNA detection method based on non-cross-linking hybridization of DNA-functionalized gold nanoparticles, resulting in a disposable colorimetric biosensor. We present a new approach for the fabrication of dye sensitized TiO2 photodetectors by an inkjet printing technique-a non-contact digital, additive, no mask and no vacuum patterning method, ideal for cost efficient mass production. The developed biosensor was compared against a dye sensitized photodetector fabricated by the traditional {"}doctor blade{"} method. Detection of gold nanoparticle aggregation was possible for concentrations as low as 1.0 nM for the {"}doctor blade{"} system, and 1.5 nM for the inkjet printed photodetector. The demonstrated sensitivity limits of developed biosensors; are comparable to those of spectrophotometric techniques (1.0 nM). Our results show that a difference higher than 17% by traditional photodetector and 6% by inkjet printed in the photoresponses for the complementary and non-complementary gold nanoprobe assays could be attained for a specific DNA sequence from Mycobacterium tuberculosis, the etiologic agent of human tuberculosis. The decrease of costs associated with molecular diagnostic provided by a platform such as the one presented here may prove of paramount importance in developing countries. (C) 2009 Elsevier B.V. All rights reserved.
Conde, J, {De La Fuente} {JM }, Baptista {PV}.
2010.
In vitro transcription and translation inhibition via DNA functionalized gold nanoparticles, dec. Nanotechnology. 21, Number 50: IOP Publishing
AbstractThe use of gold nanoparticles (AuNPs) has been gaining momentum as vectors for gene silencing strategies, combining the AuNPs' ease of functionalization with DNA and/or siRNA, high loading capacity and fast uptake by target cells. Here, we used AuNP functionalized with thiolated oligonucleotides to specifically inhibit transcription in vitro, demonstrating the synergetic effect between AuNPs and a specific antisense sequence that blocks the T7 promoter region. Also, AuNPs efficiently protect the antisense oligonucleotide against nuclease degradation, which can thus retain its inhibitory potential. In addition, we demonstrate that AuNPs functionalized with a thiolated oligonucleotide complementary to the ribosome binding site and the start codon, effectively shut down in vitro translation. Together, these two approaches can provide for a simple yet robust experimental set up to test for efficient gene silencing of AuNP-DNA conjugates. What is more, these results show that appropriate functionalization of AuNPs can be used as a dual targeting approach to an enhanced control of gene expression-inhibition of both transcription and translation.
Gomes, AQ, Correia DV, Grosso AR, Lança T, Ferreira C, Lacerda JF, Barata JT, da Silva MG, Silva-santos B.
2010.
Identification of a panel of ten cell surface protein antigens associated with immunotargeting of leukemias and lymphomas by peripheral blood γδT cells. Haematologica. 95:1397–1404., Number 8
AbstractBACKGROUND:
Vgamma9Vdelta2 T lymphocytes are regarded as promising mediators of cancer immunotherapy due to their capacity to eliminate multiple experimental tumors, particularly within those of hematopoietic origin. However, Vgamma9Vdelta2 T-cell based lymphoma clinical trials have suffered from the lack of biomarkers that can be used as prognostic of therapeutic success.
DESIGN AND METHODS:
We have conducted a comprehensive study of gene expression in acute lymphoblastic leukemias and non-Hodgkin's lymphomas, aimed at identifying markers of susceptibility versus resistance to Vgamma9Vdelta2 T cell-mediated cytotoxicity. We employed cDNA microarrays and quantitative real-time PCR to screen 20 leukemia and lymphoma cell lines, and 23 primary hematopoietic tumor samples. These data were analyzed using state-of-the-art bioinformatics, and gene expression patterns were correlated with susceptibility to Vgamma9Vdelta2 T cell mediated cytolysis in vitro.
RESULTS:
We identified a panel of 10 genes encoding cell surface proteins that were statistically differentially expressed between "gammadelta-susceptible" and "gammadelta-resistant" hematopoietic tumors. Within this panel, 3 genes (ULBP1, TFR2 and IFITM1) were associated with increased susceptibility to Vgamma9Vdelta2 T-cell cytotoxicity, whereas the other 7 (CLEC2D, NRP2, SELL, PKD2, KCNK12, ITGA6 and SLAMF1) were enriched in resistant tumors. Furthermore, some of these candidates displayed a striking variance of expression among primary follicular lymphomas and T-cell acute lymphoblastic leukemias.
CONCLUSIONS:
Our results suggest that hematopoietic tumors display a highly variable repertoire of surface proteins that can impact on Vgamma9Vdelta2 cell-mediated immunotargeting. The prognostic value of the proposed markers can now be evaluated in upcoming Vgamma9Vdelta2 T cell-based lymphoma/leukemia clinical trials.
Paliokaité, A.
2010.
Industry level foresight: designing foresight methods for Lithuanian energy sector. Enterprise and Work Innovation Studies. 6:9-51.
Abstract This paper has its starting point in the background analysis of the Lithuanian energy sector after closing down the only Lithuanian nuclear power plant in 2010. Based on the hypothesis that one of the main governance failures in this sector leading to weak industry level strategies is the lack of participatory debate and sufficient linkages between the different actors involved in the dynamic of the energy sector in Lithuania, this paper proposes industry level foresight as an instrument of long term planning. Foresight exercises could become an important instrument for reorienting energy sector policy, building new networks and linkages among the different actors, bringing new stakeholders into the strategic debate, exploring future opportunities State investment (including R&D), etc. The primary objective of this paper is therefore the design of a foresight exercise on energy sector with the aim of producing a long term strategy for this sector. The secondary objective is to address a topic on how to select foresight methods at industry level. The argument is that a better understanding of the fundamental attributes of foresight methods and their linkages to the core phases of a foresight process can provide useful insights as to how the selection of methods is carried out. The method applied in this paper is dual: firstly, the synthesis of the academic literature on the selection of foresight methods is carried out; secondly, the comparative case study analysis of three foresight cases in the Baltic Sea Region (Poland, Finland and Russia) is applied. Case study analysis allows to explore the usage of foresight methods at industry level in the Baltic Sea Region and to understand if there are any similarities in the approach, also to explore success factors and weaknesses. The analysis in this paper is comprised of four main parts. The first part provides a background analysis on the energy sector in Lithuania and justification for the foresight exercise. Second part describes the underlying frameworks and definitions in the field of foresight research. The third part develops a comparative analysis of case studies of industry level foresight. The third part provides recommendations for energy sector foresight methodology in Lithuania. The paper combines concepts and frameworks from literature (such as the Foresight Process and the Foresight Diamond) with comparative practical case study analysis. The results can be utilised by lecturers and students to describe and understand better the use of foresight methods at industry level, and by practitioners of foresight to better inform decisions during the design of more coherent methodological frameworks; as well as by the energy sector stakeholders in Lithuania and other countries.
Bicho, A, Roque ACA, Cardoso AS, Domingos P, Batalha ÍL.
2010.
In vitro studies with mammalian cell lines and gum arabic‐coated magnetic nanoparticles. Journal of Molecular Recognition. 23:536–542., Number 6
AbstractIron oxide magnetic nanoparticles {(MNPs)} were synthesized by the chemical co-precipitation method and coated with gum arabic {(GA)} by physical adsorption and covalent attachment. Cultures of mammalian cell lines {(HEK293}, {CHO} and {TE671)} were grown in the presence of uncoated and {GA-coated} {MNPs.} Cellular growth was followed by optical microscopy in order to assess the proportion of cells with particles, alterations in cellular density and the presence of debris. The in vitro assays demonstrated that cells from different origins are affected differently by the presence of the nanoparticles. Also, the methods followed for {GA} coating of {MNPs} endow distinct surface characteristics that probably underlie the observed differences when in contact with the cells. In general, the nanoparticles to which the {GA} was adsorbed had a smaller ability to attach to the cells' surface and to compromise the viability of the cultures. Copyright © 2010 John Wiley & Sons, Ltd.