Browsing by Author "Escapa, Ana Luísa"
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- Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem CellsPublication . Kranc, Kamil R.; Oliveira, Daniel; Armesilla-Diaz, Alejandro; Pacheco-Leyva, Ivette; Matias, Ana Catarina; Escapa, Ana Luísa; Subramani, Chithra; Wheadon, Helen; Trindade, Marlene; Nichols, Jennifer; Kaji, Keisuke; Enver, Tariq; Bragança, JoséIdentifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.
- An efficient in vitro propagation protocol for Pinguicula lusitanica, a rare insectivorous plantPublication . Gonçalves, Sandra; Escapa, Ana Luísa; Grevenstuk, Tomás; Romano, AnabelaIn this study, an efficient protocol was developed for in vitro propagation of Pinguicula lusitanica L., a rare insectivorous plant with pharmacological value and limited reproductive capacity. The effects of two concentrations (0.1 and 0.5 mg l-1) of a range of plant growth regulators, including cytokinins (BA, KIN, and ZEA) and auxins (IAA, IBA, and NAA), and three concentrations of MS medium macronutrients (total, 1/2 and 1/4MS) on proliferation and rooting, were investigated. P. lusitanica shoots showed abundant proliferation and rooting capacity, both of which were significantly influenced by MS medium strength. The use of 1/2MS supplemented with 0.5 mg l-1 BA or KIN ensure a 29-fold rate of proliferation. Best rooting frequency and higher root number and length were attained in 1/4MS medium containing 0.2 mg l-1 IAA. Sixty percent of the plantlets were successfully acclimatized to ex vitro conditions, exhibiting normal development. These plantlets can be used to replenish declining populations in the wild and/or for the extraction of bioactive compounds, reducing pressure on wild stocks.
- Antioxidant activity and in vitro inhibition of tumor cell growth by leaf extracts from the carob tree (Ceratonia siliqua)Publication . Custódio, Luísa; Fernandes, Eliana; Escapa, Ana Luísa; López-Avilés, Sandra; Fajardo, Alba; Aligué, Rosa; Alberício, Fernando; Romano, AnabelaThe methanol leaf extracts of female cultivars of the carob tree [Ceratonia siliqua L. (Fabaceae)] and of hermaphrodite and male trees were investigated for their contents of phenolic compounds, their in vitro antioxidant activity, measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and linoleic acid system assays, and their in vitro tumor growth inhibition on HeLa cells. The different cultivars and trees showed high levels of phenols, and considerable variations in the amount of these compounds. The extracts showed significant radical scavenging activity (RSA), which was not significantly affected by the gender of the tree. From the female cultivars tested, Galhosa exhibited the highest RSA. Gender significantly affected the antioxidant activity of the extracts measured by the linoleic acid system assay, and males and hermaphrodites showed the highest activities. The extracts displayed a remarkable ability to inhibit tumor cell proliferation, and their bioactivity varied with different cultivars or trees tested. Extracts from male and hermaphrodite trees exhibited higher capacity to inhibit the proliferation of HeLa cells than the female cultivars.
- Antioxidant and cytotoxic activities of carob tree fruit pulps are strongly influenced by Gender and cultivarPublication . Custódio, Luísa; Fernandes, Eliana; Escapa, Ana Luísa; Fajardo, Alba; Aligué, Rosa; Alberício, Fernando; Neng, Nuno Rosa; Nogueira, José Manuel F.; Romano, AnabelaExtracts from fruit pulps of six female cultivars and two hermaphrodite Portuguese carob trees [(Ceratonia siliqua L., Fabaceae)] exhibited strong antioxidant activity and were rich in phenolic compounds. The extracts decreased the viability of different human cancer cell lines on a dose- and time-dependent manner. Gender and cultivar significantly influenced the chemical content and the biological activities of the extracts. Extracts from hermaphrodite trees had a higher content of phenolic compounds, and exhibited higher antioxidant and cytotoxic activities. Among. females, cv. Aida had the highest radical scavenging activity and total content of phenolics, Mulata the highest capacity to inhibit lipid oxidation and Gasparinha the strongest cytotoxic activity on HeLa cells. The decrease in cell viability was associated with apoptosis on HeLa and MDA-MB-231 lines. (+)-Catechin and gallic acid (GA) were the main compounds identified in the extracts, and GA contributed to the antioxidant activity. Our results show that the antioxidant and cytotoxic activities of carob tree fruit pulps are strongly influenced by gender and cultivar, and provide new knowledge about the advantages of hermaphrodite trees over female cultivars, namely, as a source of compounds with biological interest, which may represent an increase of their agronomic interest.
- In vitro cytotoxic effects and apoptosis induction by a methanol leaf extract of carob tree (Ceratonia siliqua L.)Publication . Custódio, Luísa; Escapa, Ana Luísa; Fernandes, Eliana; Fajardo, Alba; Aligué, Rosa; Alberício, Fernando; Neng, Nuno Rosa; Nogueira, José Manuel F.; Romano, AnabelaThis research evaluated the in vitro apoptotic inducing properties of a methanol leaf extract of carob tree (Ceratonia siliqua L.) on a human cervical adenocarcinoma cell line (HeLa). The cell viability effect on a prostate (DU-145), breast (MDA-MB-231) and colon cell line (HCT-166) was also assessed. The effect of the extract on reactive oxygen species (ROS) production by HeLa cells was studied, and a phytochemical evaluation was made by high performance liquid chromatography with diode array detection (HPLC). Total mean yield of identified phenols was 261.1 mg/g DW, and (+)-catechin was the major compound (76.8 mg/g DW). The extract decreased cell viability in a dose-and time-dependent manner, and a more pronounced effect on HeLa line was observed. In vitro cytotoxic activity was associated with apoptosis, but not to the increase of ROS production. Among the tested compounds identified in the extract, the highest activity was detected with gallic acid (GA), (+)-catechin and quercetin, with reductions in HeLa cells viability down to 8.0, 11.9 and 27.1%, respectively. This is the first report on the apoptotic activity of a leaf extract of carob tree on a human cancer cell line, suggesting that it may be a potential source of chemopreventive compounds.
- Sapwood of carob tree (Ceratonia siliqua L.) as a potential source of bioactive compoundsPublication . Custódio, Luísa; Escapa, Ana Luísa; Patarra, João; Aligué, Rosa; Alberício, Fernando; Neng, Nuno Rosa; Nogueira, José Manuel F.; Romano, AnabelaMethanol (ME) and hot water extracts (WE) of carob tree sapwood (Ceratonia siliqua L.) exhibited high antioxidant activity and were rich in phenolic compounds, with the main compounds identified by HPLC/DAD as gentisic acid and (-)-epicatechin. The ME displayed a high in vitro antitumor activity against human tumoural cell lines and reduced intracellular ROS production by HeLa cells after treatment with H2O2. (-)-Epicatechin was shown to contribute to the cytotoxic activity of the ME. This is the first report on the biological activity of carob tree sapwood.