Percorrer por autor "Brodelius, Maria"
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- Fatty acids profile of selected Artemisia spp. plants: health promotionPublication . Carvalho, Isabel Saraiva de; Teixeira, Monica; Brodelius, MariaIn the present study we report the fatty acids profile of thirteen species of Artemisia, a hardy herb or shrub, analyzed by gas chromatography connected to a mass detector (GC-MS) for their nutritional value and their potential exploitation as a new source of essential fatty acids. Total lipids content ranged from 3.31 ± 0.19 to 17.78 ± 0.27 mg/g (fresh weight). The three most abundant fatty acids were C16:0, C18:2ω6 and C18:3ω3. Unsaturated fatty acids predominated in all the Artemisia species are studied with the α-linolenic acid (ALA) and linoleic acid (LA), which are essential for normal human growth, health promotion, and disease prevention. The predominant ω3 PUFA acid in all Artemisia species analyzed, was linolenic acid, with Artemisia gmellini, Artemisia ludoviciana and Artemisia vulgaris, showing higher amounts of this fatty acid, all thirteen species, analyzed in this study, were also rich in oleic acid (ω9) and linoleic acid (ω6), accounted for 50–70% of total PUFA. The ratio of ω3 PUFA to ω6 PUFA was similar in all species, varying from 1.0 to 3.0. Identifying Artemisia species as newer sources of PUFAs and enriching or optimizing the ω3FAs in known plant sources offer us ways of increasing the availability of ω3FAs in the food supply.
- Molecular cloning and expression analysis of three omega-6 desaturase genes from purslane (Portulaca oleracea L.)Publication . Teixeira, Monica; Coelho, N.; Olsson, M. E.; Brodelius, P. E.; Carvalho, Isabel Saraiva de; Brodelius, MariaTwo full-length cDNA clones of PoleFAD2 and one full-length cDNA clone of PoleFAD6, encoding omega-6 fatty acid desaturases, the key enzymes for the conversion of oleic into linoleic acid, were isolated from purslane (Portulaca oleracea L.) leaves and seeds. The deduced amino acid sequence of both isoforms of PoleFAD2 showed higher similarities to other microsomal omega-6 desaturases then to PoleFAD6 or other plastidial orthologues, and vice versa. Expression analysis by RT-PCR showed that all genes are expressed in all tissues of purslane tested, but higher levels of mRNA accumulation were detected in reproductive organs and cells that proliferate rapidly or store lipids. Wounding affected the levels of mRNA accumulation of both, FAD2 and FAD6 genes in purslane leaves, while chilling stress affected only FAD2 transcript level. The expression patterns observed reflect the discrete roles of these genes in membrane synthesis for cell division, thylakoid development, and lipid storage or in the biosynthetic pathway for the production of signaling molecules that influence plant development or defense.
- Omega-3 fatty acid desaturase genes isolated from Purslane (Portulaca oleracea L.): expression in different tissues and response to cold and wound stressPublication . Teixeira, Monica; Carvalho, Isabel Saraiva de; Brodelius, MariaTwo full-length cDNA clones PoleFAD7 and PoleFAD8, encoding plastidial omega-3 fatty acid desaturases were isolated from purslane (Portulaca oleracea). The encoded enzymes convert linoleic to alpha-linolenic acid (C18:3n-3). Three histidine clusters characteristic of fatty acid desaturases, a putative chloroplast transit peptide in the N-terminal, and three putative transmembrane domains were identified in the sequence. Both genes were expressed in all analyzed tissues showing different levels of expression. PoleFAD7 was up-regulated by wounding but not by low temperature. PoleFAD8 was up-regulated by cold stress but not by wounding. Total fatty acid and linolenic acid content were higher both, in wounded and intact leaves of plants exposed to low temperature.