Conde, J, Ambrosone A, Sanz V, Hernandez Y, Marchesano V, Tian F, Child H, Berry {CC }, Ibarra R}{M, Baptista {PV}, Tortiglione C, {de la Fuente} {JM }.
2012.
Design of multifunctional gold nanoparticles for in vitro and in vivo gene silencing, sep. ACS Nano. 6:8316–8324., Number 9: ACS - American Chemical Society
AbstractOver the past decade, the capability of double-stranded RNAs to interfere with gene expression has driven new therapeutic approaches. Since small interfering RNA (siRNAs, 21 base pair double-stranded RNA) was shown to be able to elicit RNA interference (RNAi), efforts were directed toward the development of efficient delivery systems to preserve siRNA bioactivity throughout the delivery route, from the administration site to the target cell. Here we provide evidence of RNAi triggering, specifically silencing c-myc protooncogene, via the synthesis of a library of novel multifunctional gold nanoparticles (AuNPs). The efficiency of the AuNPs is demonstrated using a hierarchical approach including three biological systems of increasing complexity: in vitro cultured human cells, in vivo invertebrate (freshwater polyp, Hydra), and in vivo vertebrate (mouse) models. Our synthetic methodology involved fine-tuning of multiple structural and functional moieties. Selection of the most active functionalities was assisted step-by-step through functional testing that adopted this hierarchical strategy. Merging these chemical and biological approaches led to a safe, nonpathogenic, self-tracking, and universally valid nanocarrier that could be exploited for therapeutic RNAi.
Marques, J, Parente F, Costa A, Martins M, Indelicato P, Santos J.
2012.
Decay of the 1s22s3p 3P0 level in Be-like ions, Nov. Physical Review A. 86:052521.
AbstractThe lifetime of the 1s22s3p 3P0 level of selected Be-like ions, from Z = 5 to Z = 92, is calculated using the multiconfiguration Dirac-Fock method including QED corrections. Full correlation up to the 4f subshell in both initial and final levels for all possible decay modes was included. The results are in reasonable agreement with the scarce existing experimental and theoretical data.
Santana, SDF, Dhadge VL, Roque ACA.
2012.
Dextran-Coated Magnetic Supports Modified with a Biomimetic Ligand for IgG Purification. ACS Applied Materials and Interfaces. 4(11):5907–5914.
Abstractextran-coated iron oxide magnetic particles modified with ligand 22/8, a protein A mimetic ligand, were prepared and assessed for IgG purification. Dextran was chosen as the agent to modify the surface of magnetic particles by presenting a negligible level of nonspecific adsorption. For the functionalization of the particles with the affinity ligand toward antibodies, three methods have been explored. The optimum coupling method yielded a theoretical maximum capacity for human IgG calculated as 568 ± 33 mg/g and a binding affinity constant of 7.7 × 104 M–1. Regeneration, recycle and reuse of particles was also highly successful for five cycles with minor loss of capacity. Moreover, this support presented specificity and effectiveness for IgG adsorption and elution at pH 11 directly from crude extracts with a final purity of 95% in the eluted fraction.
Silva, J.
2012.
Ditto – Deterministic Execution Replay for the Java Virtual Machine on Multi-processors. : Instituto Superior Técnico
AbstractIn this work, we propose RATS, a middleware to enhance and extend the Terracotta framework for Java with the ability to transparently execute multi-threaded Java applications to provide a single-system image. It supports efficient scheduling of threads, according to available resources, across several nodes in a Terracotta cluster, taking advantage of the extra computational and memory resources available. It also supports profiling to gather application characteristics such as dispersion of thread workload, thread inter-arrival time and resource usage of the application. Profiling and clustering capabilities are inserted with the help of byte code instrumentations. We developed a range of alternative scheduling heuristics and classify them based on the application and cluster behavior. The middleware is tested with different applications with varying thread characteristics to assess and classify the scheduling heuristics with respect to application speed-ups. Results indicate that, for a CPU intensive application, it is possible to classify the scheduling heuristic based on application and cluster properties and also achieve linear speed ups. Furthermore, we show that a memory intensive application is able to scale its memory usage considerably when compared to running the application on a single JVM.
Soares, PIP, Dias S, Novo C, Ferreira I, Borges JP.
2012.
Doxorubicin vs. ladirubicin: methods for improving osteosarcoma treatment. Mini reviews in medicinal chemistry. 12(12):1239–1249., Number 12: Bentham Science Publishers
AbstractOsteosarcoma is the most common primary bone tumor in children and adolescents, with a 5-year disease free survival rate of 70%. Current chemotherapy regimens comprise a group of chemotherapeutic agents in which doxorubicin is included. However, tumor resistance to anthracyclines and cardiotoxicity are limiting factors for its usage. Liposomal formulations of doxorubicin improve its anti-cancer effects but are still insufficient. The research in this area has lead to the production of anthracyclines analogues, such as ladirubicin, the leading compound of alkylcyclines. This new anticancer agent has shown promising results in vivo and in vitro, being effective against osteosarcoma cell lines, including those with a multidrug resistant phenotype. In phase I clinical trials, this molecule caused mild side effects and did not induce significant cardiotoxicity at doses ranging from 1 to 16 mg/m2, resulting in a peak plasma concentration (Cmax) ranging from 0.5 to 1.5 μM. The recommended doses for phase II studies were 12 and 14 mg/m2 in heavily and minimally pretreated/non-pretreated patients, respectively. Phase II clinical trials in ovary, breast, colorectal cancer, NSCLC and malignant melanoma are underway. Given the improved molecular targeting efficacy of these new compounds, ongoing approaches have sought to improve drug delivery systems, to improve treatment efficacy while reducing systemic toxicity. The combination of these two approaches may be a good start for the discovery of new treatment for osteosarcoma.
Grosso, AR, {De Almeida} SF, Braga J, Carmo-fonseca M, de Almeida SF, Braga J, Almeida FD, Carmo-fonseca M, Res G, Almeida FD, Grosso AR, Carmo-fonseca M.
2012.
Dynamic transitions in RNA polymerase II density profiles during transcription termination. Genome research. 22:1447–1456., Number 8
AbstractEukaryotic protein-coding genes are transcribed by RNA polymerase II (RNAPII) through a cycle composed of three main phases: initiation, elongation, and termination. Recent studies using chromatin immunoprecipitation coupled to high-throughput sequencing suggest that the density of RNAPII molecules is higher at the 3'-end relative to the gene body. Here we show that this view is biased due to averaging density profiles for "metagene" analysis. Indeed, the majority of genes exhibit little, if any, detectable accumulation of polymerases during transcription termination. Compared with genes with no enrichment, genes that accumulate RNAPII at the 3'-end are shorter, more frequently contain the canonical polyadenylation [poly(A)] signal AATAAA and G-rich motifs in the downstream sequence element, and have higher levels of expression. In 1% to 4% of actively transcribing genes, the RNAPII enriched at the 3'-end is phosphorylated on Ser5, and we provide evidence suggesting that these genes have their promoter and terminator regions juxtaposed. We also found a striking correlation between RNAPII accumulation and nucleosome organization, suggesting that the presence of nucleosomes after the poly(A) site induces pausing of polymerases, leading to their accumulation. Yet we further observe that nucleosome occupancy at the 3'-end of genes is dynamic and correlates with RNAPII density. Taken together, our results provide novel insight to transcription termination, a fundamental process that remains one of the least understood stages of the transcription cycle.
Palma, AS, Liu Y, Zhang Y, Zhang H, Luis AS, Carvalho AL, Gilbert HJ, Boraston A, Fontes CMGA, Chai W, Ten F.
2012.
Designer-oligosaccharide microarrays to decipher ligands in mammalian and prokaryotic glucan-recognition systems. Glycobiology. 22:1612-1613., Number 11
Abstractn/a
Timoteo, CG, Guilherme M, Penas D, Folgosa F, Tavares P, Pereira AS.
2012.
Desulfovibrio vulgaris bacterioferritin uses H2O2 as a co-substrate for iron oxidation and reveals DPS-like DNA protection and binding activities. BIOCHEMICAL JOURNAL. {446}:{125-133}., Number {1}
AbstractA gene encoding Bfr (bacterioferritin) was identified and isolated from the genome of Desulfovibrio vulgaris cells, and overexpressed in Escherichia coli. In vitro, H2O2 oxidizes Fe2+ ions at much higher reaction rates than O-2. The H2O2 oxidation of two Fe2+ ions was proven by Mossbauer spectroscopy of rapid freeze-quenched samples. On the basis of the Mossbauer parameters of the intermediate species we propose that D. vulgaris Bfr follows a mineralization mechanism similar to the one reported for vertebrate H-type ferritins subunits, in which a diferrous centre at the ferroxidase site is oxidized to diferric intermediate species, that are subsequently translocated into the inner nanocavity. D. vulgaris recombinant Bfr oxidizes and stores up to 600 iron atoms per protein. This Bfr is able to bind DNA and protect it against hydroxyl radical and DNase deleterious effects. The use of H2O2 as an oxidant, combined with the DNA binding and protection activities, seems to indicate a DPS (DNA-binding protein from starved cells)-like role for D. vulgaris Bfr.
Ferraz, R, Branco LC, Marrucho IM, Araujo JMM, Rebelo LPN, da Ponte MN, Prudencio C, Noronha JP, Petrovski Z.
2012.
Development of novel ionic liquids based on ampicillin. Medchemcomm. 3:494-497., Number 4
Abstractn/a