Browsing by Author "Sousa, Carolina Bruno de"
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- A diverse assemblage of RNA and DNA viruses found in mosquitoes collected in southern PortugalPublication . Silva, Manuel; Morais, Paulo; Maia, Carla; Sousa, Carolina Bruno de; Gouveia de Almeida, Antonio Paulo; Parreira, RicardoThis work describes the detection and partial characterization of mosquito-borne virus genomic sequences, based on the analysis of mosquitoes collected from the Spring to Fall of 2018 in the Algarve (southern Portugal). The viral survey that was carried out using multiple primer sets disclosed the presence of both RNA and DNA viral sequences in these mosquitoes, which were subsequently analysed using maximum likelihood and Bayesian phylogenetic reconstruction methods. The obtained results brought to light three lineages of insect-specific flaviviruses, a monophyletic cluster of bunyaviruses from an unassigned group within the Phenuiviridae family, as well as brevidensoviruses (Parvoviridae, Densovirinae:). The latter two groups of viruses were here described for the first time in mosquitoes from Portugal. Results relating to the tentative isolation of the putative viruses identified in C6/36 cells are also shown, and the serendipitous, although not unexpected, isolation a Negev-like Nelorpivirus from Culex laticinctcus mosquitoes is reported.
- Antileishmanial activity of meroditerpenoids from the macroalgae Cystoseira baccataPublication . Sousa, Carolina Bruno de; Gangadhar, Katkam N.; Morais, Thiago R.; Conserva, Geanne A. A.; Vizetto-Duarte, C; Pereira, H.; Laurenti, Marcia D.; Campino, Lenea; Levy, Debora; Uemi, Miriam; Barreira, Luísa; Custódio, L.; Passero, Luiz Felipe D.; Lago, Joao Henrique G.; Varela, JoãoThe development of novel drugs for the treatment of leishmaniases continues to be crucial to overcome the severe impacts of these diseases on human and animal health. Several bioactivities have been described in extracts from macroalgae belonging to the Cystoseira genus. However, none of the studies has reported the chemical compounds responsible for the antileishmanial activity observed upon incubation of the parasite with the aforementioned extracts. Thus, this work aimed to isolate and characterize the molecules present in a hexane extract of Cystoseira baccata that was found to be bioactive against Leishmania infantum in a previous screening effort. A bioactivity-guided fractionation of the C. baccata extract was carried out and the inhibitory potential of the isolated compounds was evaluated via the MIT assay against promastigotes and murine macrophages as well as direct counting against intracellular amastigotes. Moreover, the promastigote ultrastructure, DNA fragmentation and changes in the mitochondrial potential were assessed to unravel their mechanism of action. In this process, two antileishmanial meroditerpenoids, (3R)- and (3S)-tetraprenyltoluquinol (1a/1b) and (3R)- and (3S)-tetraprenyltoluquinone (2a/2b), were isolated. Compounds 1 and 2 inhibited the growth of the L. infantum promastigotes (IC50 = 44.9 +/- 4.3 and 94.4 +/- 10.1 mu M, respectively), inducing cytoplasmic vacuolization and the presence of coiled multilamellar structures in mitochondria as well as an intense disruption of the mitochondrial membrane potential. Compound 1 decreased the intracellular infection index (IC50 = 25.0 +/- 4.1 mu M), while compound 2 eliminated 50% of the intracellular amastigotes at a concentration > 88.0 mu M. This work identified compound 2 as a novel metabolite and compound 1 as a biochemical isolated from Cystoseira algae displaying antileishmanial activity. Compound 1 can thus be an interesting scaffold for the development of novel chemotherapeutic molecules for canine and human visceral leishmaniases studies. This work reinforces the evidence of the marine environment as source of novel molecules. (C) 2017 Elsevier Inc. All rights reserved.
- Can macroalgae provide promising anti-tumoral compounds? A closer look at Cystoseira tamariscifolia as a source for antioxidant and anti-hepatocarcinoma compoundsPublication . Vizetto-Duarte, C; Custódio, Luísa; Acosta, Gerardo; Lago, João H. G.; Morais, Thiago R.; Sousa, Carolina Bruno de; Gangadhar, Katkam N.; Rodrigues, Maria Joao; Pereira, Hugo; Lima, Raquel T.; Vasconcelos, M. Helena; Barreira, Luísa; Rauter, Amélia P.; Albericioi, Fernando; Varela, J.Marine organisms are a prolific source of drug leads in a variety of therapeutic areas. In the last few years, biomedical, pharmaceutical and nutraceutical industries have shown growing interest in novel compounds from marine organisms, including macroalgae. Cystoseira is a genus of Phaeophyceae (Fucales) macroalgae known to contain bioactive compounds. Organic extracts (hexane, diethyl ether, ethyl acetate and methanol extracts) from three Cystoseira species (C. humilis, C. tamariscifolia and C. usneoides) were evaluated for their total phenolic content, radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'- azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, and antiproliferative activity against a human hepatocarcinoma cell line (HepG2 cells). C. tamariscifolia had the highest TPC and RSA. The hexane extract of C. tamariscifolia (CTH) had the highest cytotoxic activity (IC50 = 2.31 mu g/mL), and was further tested in four human tumor (cervical adenocarcinoma HeLa; gastric adenocarcinoma AGS; colorectal adenocarcinoma HCT-15; neuroblastoma SH-SY5Y), and two non-tumor (murine bone marrow stroma S17 and human umbilical vein endothelial HUVEC) cell lines in order to determine its selectivity. CTH strongly reduced viability of all tumor cell lines, especially of HepG2 cells. Cytotoxicity was particularly selective for the latter cells with a selectivity index = 12.6 as compared to non-tumor cells. Incubation with CTH led to a 2-fold decrease of HepG2 cell proliferation as shown by the bromodeoxyuridine (BrdU) incorporation assay. CTH-treated HepG2 cells presented also pro-apoptotic features, such as increased Annexin Wpropidium iodide (PI) binding and dose-dependent morphological alterations in DAPI-stained cells. Moreover, it had a noticeable disaggregating effect on 3D multicellular tumor spheroids. Deme boxy cystoketal chromane, a derivative of the meroditerpenoid cystoketal, was identified as the active compound in CTH and was shown to display selective in vitro cYtotoxicitY towards HepG2 cells.