Browsing by Author "Raimundo, Joana"
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- Accumulation, elimination and neuro-oxidative damage under lanthanum exposure in glass eels (Anguilla anguilla)Publication . Figueiredo, Cátia; F. Grilo, Tiago; Lopes, Clara; Brito, Pedro; Diniz, Mário S.; Caetano, Miguel; Rosa, Rui; Raimundo, JoanaRare earth elements (REEs) comprise elements from lanthanum to lutetium that together with yttrium and scandium are emergent contaminants of critical importance for numerous groundbreaking environmental technologies. Transfer to aquatic ecosystems is expected to increase, however, little information is known about their potential impacts in marine biota. Considering the endangered conservation status of the European eel (Anguilla anguilla) and the vulnerability of early fish life stages to contaminants, we exposed glass eels, through water, to an environmentally relevant concentration (120 ng.L-1) of lanthanum (La) for 7 days (plus 7 days of depuration). The aim was to study the accumulation and elimination of La in eel's body and subsequent quantification of acetylcholinesterase (AchE), lipid peroxidation and antioxidant enzymatic machinery. Accumulation peaked after 72 h-exposure to La, decreasing afterwards, even in continuous exposure. Accumulation was higher in the viscera, followed by the skinless body and ultimately in the head, possibly as a protective mechanism to cope with La neurotoxicity. A significant increase in AChE activity was observed in La-exposed glass eels, suggesting that La3+ may inhibit the binding of acetylcholine. A depression in lipid peroxidation was registered under La exposure, possibly indicating that La3+ may play physiological activities and functions as a free radical scavenger. Catalase activity was significantly inhibited in La-exposed glass eels after 72 h, indicating that the availability of La may induce physiological impairment. The quantification of Glutathione S-Transferase activity revealed no differences between control and La-exposed organisms. Further investigation is needed towards understanding the biological effects of REEs.
- Cuttlefish capsule: An effective shield against contaminants in the wildPublication . Rosa, Inês; Raimundo, Joana; Lopes, Vanessa; Brandão, Cláudio; Couto, Ana; Santos, Catarina; Cabecinhas, Adriana S.; Cereja, R; Calado, Ricardo; Caetano, Miguel; Rosa, RuiIncreasing anthropogenic pressures in estuaries are responsible for the rise of contaminants in several compartments of these ecosystems. Species that benefit from the nursery services provided by estuaries are exposed to such contaminants (e.g. metals and metalloids). It is therefore relevant to understand if marine invertebrates that use these areas as spawning grounds accumulate contaminants in their tissues throughout embryogenesis. This study aimed to quantify As, Co, Cr, Cu, Mn, Ni, Se, Pb, V and Zn concentrations in both capsule and embryos of the common cuttlefish (Sepia officinalis) in Sado Estuary (Portugal). Moreover, embryos at their initial, intermediate and final stage of development were collected in sites subjected to different anthropogenic pressures. In general, the capsule accumulated higher element concentration throughout embryogenesis which indicates that the capsule acts as an effective barrier against contaminants uptake by the embryo. Although the capsule becomes thinner throughout embryogenesis, embryo's protection does not seem to be compromised at later development stages. Additionally, the higher concentrations of As, Cu, Se and Zn in the embryo in comparison to the capsule suggests important biological roles during the embryogenesis of this cephalopod mollusc.
- Rooting and survival of cork oak cuttingsPublication . Ribeiro, Maria Margarida; Raimundo, Joana; Amâncio, SaraThe cork oak (Quercus suber L.) has remarkable ecological, social and economic value in the Mediterranean region. Due to the growing economic interest in cork, human intervention in the plant production and renewal of this species is crucial. Thus, the optimization of the propagation methodologies to produce selected and improved trees for high quality cork production is a key factor in the species improvement program. Rooting and survival of cuttings are greatly affected by several external and internal factors. To circumvent this problem, experiments were made using young seedlings as a source of cork oak cuttings for two consecutive years. We studied the influence of the application of synthetic auxins, indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA), the IBA concentration and the basal bark removal in rooting and survival of cork oak cuttings. The IBA improved the rooting, the survival and the mean length of the longest root per rooted cutting, but not the mean number of primary roots produced. The basal bark removal associated with 0.5% of IBA gave the highest percent of rooting and plant survival (60% and 54%, respectively). The application of 0.1% of NAA had no significant influence on the rooting and survival. Thus, it is possible to draw the conclusion that wounding along with 0.5 % IBA produced the highest percentage of rooting and survival with cuttings planted in April, however complementary studies involving different physical and chemical conditions are required
- Yttrium and rare earth elements fractionation in salt marsh halophyte plantsPublication . Brito, Pedro; Malvar, Margarida; Galinha, Catarina; Caçador, Isabel; Canário, João; Araújo, M. Fátima; Raimundo, JoanaSalt marshes act as natural deposits of different metals (e.g. heavy-metals), while halophyte plants are known to retain and accumulate them in the different tissues. Scarce data exists on accumulation, partition and fractionation of YREE in these plants. To study the relationship between halophyte plants and YREE, contents of these metals were determined by ICP-MS in sediment, and in the different plants organs, from Rosário's salt marsh, in Tagus estuary (SW Europe). Results show significant differences (p < 0.001) in YREE contents between sediments. In non-colonised sediment Y was lower (5.0-18 mg·kg-1) compared to the Sarcocornia fruticosa and Spartina maritima sediment cores (19-26 and 20-26 mg·kg-1, respectively). The same was observed for ΣREE, with lower values in non-colonised sediment (32-138 mg·kg-1), while colonised ones presented higher contents (146-174 and 151-190 mg·kg-1, for S. fruticosa and S. maritima, respectively). These significant differences (p < 0.05) are explained by the sediments' nature. Yttrium and ΣREE Al-normalised ratios in non-colonised sediment ranged from 1.5 to 2.3 and 11 to 13, respectively. The colonised sediments revealed significant higher ratios (particularly for ΣREE/Al ratios; p < 0.001), varying from Y/Al: 1.8-2.3 and ΣREE: 13-16 for S. fruticosa, and Y/Al: 1.4-2.3 and ΣREE: 12-18, for S. maritima. Results suggest that these plants may promote YREE enrichment in the sediments. No differences in fractionation patterns among sediments and in both species roots were found, but fractionation was different from those in the sediment, with similar middle-REE (MREE) enrichment and no light-REE (LREE) and heavy-REE (HREE) fractionation. No evidence of YREE transfer to aboveground organs was observed. Different fractionation patterns in stems and leaves were registered, with clear enrichment of LREE relative to HREE and an increase in the MREE enrichment. Therefore, these plants showed low ability to accumulate and translocate YREE but may promote its enrichment in the sediments.