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- Asparagopsis armata and Sphaerococcus coronopifolius as a natural source of antimicrobial compoundsPublication . Pinteus, Susete; Alves, Celso; Monteiro, Hugo; Ernesto Araújo; Horta, André; Pedrosa, RuiMethanol, n-hexane and dichloromethane extracts of twelve marine macro-algae (Rhodophyta, Chlorophyta and Heterokontophyta divisions) from Peniche coast (Portugal) were evaluated for their antibacterial and antifungal activity. The antibacterial activity was evaluated by disc diffusion method against Bacillus subtilis (gram positive bacteria) and Escherichia coli (gram negative bacteria). Saccharomyces cerevisiae was used as a model for the antifungal activity by evaluating the growth inhibitory activity of the extracts. The high antibacterial activity was obtained by the Asparagopsis armata methanolic extract (10 mm–0.1 mg/disc), followed by the Sphaerococcus coronopifoliusn-hexane extract (8 mm–0.1 mg/disc), and the Asparagopsis armata dichloromethane extract (12 mm–0.3 mg/disc) against Bacillus subtilis. There were no positive results against Escherichia coli. Sphaerococcus coronopifolius revealed high antifungal potential for n-hexane (IC50 = 40.2 µg/ml), dichloromethane (IC50 = 78.9 µg/ml) and methanolic (IC50 = 55.18 µg/ml) extracts against Saccharomyces cerevisiae growth. The antifungal potency of the Sphaerococcus coronopifolius extracts was similar with the standard amphotericin B. Asparagopsis armata and Sphaerococcus coronopifolius reveal to be interesting sources of natural compounds with antimicrobial properties. © 2015, Springer Science+Business Media Dordrecht.
- Characterization of antiproliferative potential and biological targets of a copper compound containing 4′-phenyl terpyridinePublication . Mendo, Ana Soraia; Figueiredo, Sara; Roma-Rodrigues, Catarina; Videira, Paula A.; Ma, Zhen; Diniz, Mário; Larguinho, Miguel; Costa, Pedro M.; Lima, João C.; Pombeiro, Armando J. L.; Baptista, Pedro V.; Fernandes, Alexandra R.Several copper complexes have been assessed as anti-tumor agents against cancer cells. In this work, a copper compound [Cu(H2O){OS(CH3)2}L](NO3)2 incorporating the ligand 4′-phenyl-terpyridine antiproliferative activity against human colorectal, hepatocellular carcinomas and breast adenocarcinoma cell lines was determined, demonstrating high cytotoxicity. The compound is able to induce apoptosis and a slight delay in cancer cell cycle progression, probably by its interaction with DNA and induction of double-strand pDNA cleavage, which is enhanced by oxidative mechanisms. Moreover, proteomic studies indicate that the compound induces alterations in proteins involved in cytoskeleton maintenance, cell cycle progression and apoptosis, corroborating its antiproliferative potential.
- Detection of QnrB54 and Its Novel Genetic Context in Citrobacter freundii Isolated from a Clinical CasePublication . Campos, Maria Jorge; Palomo, Gonzalo; Hormeño, Lorena; Rodrigues, Américo; Sánchez-Benito, Rosario; Píriz, Segundo; Quesada, AlbertoLETTER Quinolone resistance in Enterobacteriaceae is mediated by mutations in the quinolone resistance-determining regions (QRDR) of topoisomerase genes and/or by plasmid-mediated quinolone resistance determinants (PMQR) such as the qnr genes encoding pentapeptide repeat proteins (1). The qnrB family is represented by 80 different alleles (http://www.lahey.org/qnrStudies/); most of them originated from Citrobacter strains and spread to other Enterobacteriaceae species (2). This work describes the identification of a new allele of the quinolone resistance protein QnrB, QnrB54, in a human clinical isolate of Citrobacter freundii detected in Spain.
- Marine Natural Products as Anticancer AgentsPublication . Alves, Celso; Diederich, MarcCancer remains one of the major threats to human health and one of the deadliest diseases worldwide [1]. Therapy failure and consequent cancer relapse are the main factors contributing to high cancer mortality, making it crucial to find and develop new therapeutic options. Over the last few decades, natural products became one of the key drivers in the drug development of innovative cancer treatments [2]. In opposition to drug development from terrestrial resources, the marine environment only recently emerged as a prolific source of unparalleled structurally active metabolites [3]. Due to their excellent scaffold diversity, structural complexity, and ability to act on multiple cell signaling networks involved in carcinogenesis, marine natural products are ideal candidates to inspire the development of novel anticancer medicines [4,5].
- The Quest for Phenolic Compounds from Macroalgae: A Review of Extraction and Identification MethodologiesPublication . Santos, Sónia A. O.; Pais, Adriana C. S.; Rocha, Sílvia M.; Silvestre, Armando J. D.; Félix, RafaelThe current interest of the scientific community for the exploitation of high-value compounds from macroalgae is related to the increasing knowledge of their biological activities and health benefits. Macroalgae phenolic compounds, particularly phlorotannins, have gained particular attention due to their specific bioactivities, including antioxidant, antiproliferative, or antidiabetic. Notwithstanding, the characterization of macroalgae phenolic compounds is a multi-step task, with high challenges associated with their isolation and characterization, due to the highly complex and polysaccharide-rich matrix of macroalgae. Therefore, this fraction is far from being fully explored. In fact, a critical revision of the extraction and characterization methodologies already used in the analysis of phenolic compounds from macroalgae is lacking in the literature, and it is of uttermost importance to compile validated methodologies and discourage misleading practices. The aim of this review is to discuss the state-of-the-art of phenolic compounds already identified in green, red, and brown macroalgae, reviewing their structural classification, as well as critically discussing extraction methodologies, chromatographic separation techniques, and the analytical strategies for their characterization, including information about structural identification techniques and key spectroscopic profiles. For the first time, mass spectrometry data of phlorotannins, a chemical family quite exclusive of macroalgae, is compiled and discussed
- Sandy beach macrofaunal assemblages as indicators of anthropogenic impacts on coastal dunesPublication . Bessa, Filipa; Cunha, David; Gonçalves, Sílvia; Marques, João CarlosOcean sandy beaches are iconic recreational assets to society and have undergone rapid degradation caused by both natural and anthropogenic pressures. A major effect of urbanisation on biota stems from artificial structures placed in aquatic systems. While the installation of these structures has been widespread, our understanding of how they impact shoreline habitats and fauna is relatively limited. On the sandy Leirosa Beach, on the European Atlantic coast (Portugal), a decade of cumulative impacts was recorded, with disruption of the frontal dune, dune nourishment and the incorporation of geotextiles to reconstruct the dune and maintain it as an artificial structure. Two years after the dune rehabilitation process at Leirosa Beach, seasonal sampling campaigns (from spring 2010 to winter 2011) were carried out to assess the effects of the artificial dune (and the first signs of its eventual disruption) on macrofauna compared to a natural dune on the same beach. During the study period, the rehabilitated foredune maintained the average slope, with similar sediment characteristics (finer sediments) when compared with the natural dune system, with no physical significant differences being appreciated between the two sites. The macrofaunal assemblages were represented especially by crustaceans (amphipods and isopods), with similar mean total density, taxon richness and diversity between sites. Special attention was given to the supralittoral species, and the results revealed that the natural zone harboured a significantly higher density of sandhopper Talitrus saltator with respect to the artificial zone. PERMANOVA results detailed the significant difference that occurred, particularly during the warmer seasons (spring and summer 2010), the recruitment period described for this species along this coast. In fact, SIMPER analysis revealed that T. saltator accounted for 46% of the dissimilarities between the natural and artificial dune sites. The presence of geotextiles extending across the supralittoral zone appeared, on the one hand, to allow for the presence of talitrids, but the application of textiles around the area prevented them from burrowing, thus causing them to avoid the rehabilitated area. The results highlighted the potentially negative effects of this artificial dune system if textile disruption continues, and the usefulness of T. saltator as an effective and reliable ecological indicator for these ecosystems. Thus, evaluating the risks and magnitude of human interventions is a major challenge for sandy beach ecologists, and baseline information is required if we are to better understand how resident macrofaunal species deal with future impact scenarios.