Browsing by Author "Neves, Bruna"
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- Effects of outdoor and indoor cultivation on the polar lipid composition and antioxidant activity of Nannochloropsis oceanica and Nannochloropsis limnetica: A lipidomics perspectivePublication . Couto, Daniela; Conde, Tiago A.; Melo, Tânia; Neves, Bruna; Costa, Margarida; Cunha, Pedro; Guerra, Inês; Correia, Nádia; Silva, Joana T.; Pereira, Hugo; Varela, João; Silva, Joana; Domingues, Rosário; Domingues, PedroNannochloropsis is a genus of eicosapentaenoic acid-rich microalgae with high levels of value-added polar lipids. However, the polar lipid composition of microalgal biomass is highly dependent on culture conditions (e.g., light or temperature), which are significantly different under indoor and outdoor culture conditions. In this study, we sought to investigate the plasticity of the polar lipid profile of a marine (N. oceanica) and a freshwater (N. limnetica) species of Nannochloropsis grown in indoor and outdoor photobioreactors. To this end, the polar lipidome and fatty acid profiles were characterized by liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS), respectively. In addition, the antioxidant activity of their lipid extracts was assessed. The highest lipid contents were obtained for the two species grown indoors. LC-MS analysis identified 239 different polar lipid species, of which 220 were shared by all experimental groups. Candidate lipid biomarkers from both culture systems were proposed, including MGDG(34:2), MGDG(34:1) and PG(36:6). For both species, indoor conditions lead to lipid extracts rich in glycolipids and higher in oleic acid content. In contrast, outdoor conditions lead to higher proportions of phospholipids and betaine lipids and a higher relative content of eicosapentaenoic acid (EPA). The polar lipid profile of the two Nannochloropsis species differed primarily in the relative amounts of certain betaine lipids, mainly DGTS (which was increased in N. oceanica) and lysolipids (LPC, and LPE) (increased in N. limnetica), although the majority of lipids were observed in both species. The lipid extracts showed antioxidant activity (IC15) ranging from 30.4 +/- 1.8 to 45.7 +/- 1.6 mu mol Trolox g-1 of lipid extract. Overall, this study provides insight into the lipid metabolic adaptation of two Nannochloropsis species, providing the know-how to obtain a healthy polar lipid-rich biomass useful for novel applications in pharmaceutical, nutraceutical, or novel foods.
- Evaluation of parental and transgenerational effects of clotrimazole in Daphnia magna — A multi-parametric approachPublication . Ferreira, David; Alkimin, G. D.; Neves, Bruna; Conde, Tiago; Domingues, M. Rosário; Nunes, BrunoAzole antifungals inhibit the cytochrome P450 complex, decreasing the production of ergosterol in fungi, and compromising the biosynthesis of ecdysteroids in crustaceans, which are hormones regulating reproduction and ecdy-sis. The azole antifungal clotrimazole (CLO) raises environmental concerns due its toxicity. This work evaluated the effects on the number of moults, feeding rate, growth, reproduction, transgenerational reproductive effects on two dif-ferent generations (F0, parental generation; and F1, organisms born from F0), and energetic balance in Daphnia magna. Neonates (<24 h) were exposed to sublethal concentrations (0, 2.7, and 3.4 mg/L) of CLO, to assess its effects on the moulting process. Neonates were also exposed to environmentally realistic concentrations of CLO (0, 30,150, 750, and 3750 ng/L) for 24 and 96 h, to assess adverse effects on their feeding behaviour. Effects on energy reserves (fatty acids, glycogen, and protein levels) were also measured in animals exposed to CLO. A reproduction test was carried out to evaluate the amount and size of neonates from F0 and F1 generations. CLO exposure decreased the number of moults, and the size of organisms, but did not alter the feeding pattern of 5 days old individuals. However, neonates (<24 h) exposed to CLO had a significant decrease in their feeding pattern. CLO decreased the fatty acids content in exposed animals, but did not change glycogen and protein. CLO also decreased the size of adult daphnids from the third brood, born from animals exposed in F0; in F1 animals, the size of neonates from the third brood was decreased. This study evidenced the toxic effects caused by CLO on growth, feeding and reproduction of D. magna. Nevertheless, it is not pos-sible to conclude whether the effects are due to the inhibition of cytochrome P450 enzymes, or to unspecific effects caused by general toxic stress and decreased nutrition.