Browsing by Issue Date, starting with "2008-06"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- Bata-Tahlassema: prevalence in Algarve, PortugalPublication . Cabral, M.; Baiao, I.; Valente, I.; Eloy, M.; Freitas, M.Background. Thalassemia is a genetic disease that makes part of an heterogeneous group of mendelian disturbs characterised by a diminution or absence in the production of one of the α or β Haemoglobin A chains (α2 β2). β-thalassemia is a variance of the thalassemic disease. This disease is found in many different ethnic groups and is more incident in some geographic areas, like Mediterranic zones where Algarve is insert.
- Spatial and temporal characteristics of benthic invertebrate communities at Culbin Sands lagoon, Moray Firth, NE Scotland, and impacts of the disturbance of cockle harvestingPublication . Mariyam Mendonca, Vanda; Raffaelli, David George; Boyle, Peter; Hoskins, SteveIn the present study, Culbin Sands lagoon, a protected site in NE Scotland, was surveyed every 2 to 4 weeks during a three-year period (1994-1996) to study benthic invertebrate communities. Beds of Mytilus edulis covered 18000 m(2). 53 macroinfaunal species were identified outside these areas. The most conspicuous were: the lugworm Arenicola marina (mean up to 55 casts m(-2)); and bivalves Cerastoderma edule (mean up to 158 ind. m(-2)) and Macoma balthica (mean up to 79 ind. m(-2)) after settlement. The standing stock ranged from 20 to 32 g AFDW m(-2) yr(-1) respectively from more exposed to more sheltered areas. Most species showed a clear recruitment peak in autumn, but others (e.g. Capitella capitata, and Spionidae) displayed several peaks in a year. Communities were also compared between the Sampling sites before and after an incidental disturbance caused by cockle Cerastoderma edule harvesting, which took place in June 1995. One site showed -0.7% variation in the total standing stock, but +22% for smaller-cockles, as larger filter-feeding cockles were removed therefore enhancing their own larval settlement. Polychaete Spionidae Populations also increased after larger cockles were removed. The polychaete Arenicola marina population returned to its normal activities just after the dramatic disturbance of the sediment.
- Impairment of mineralization by metavanadate and decavanadate solutions in a fish bone-derived cell linePublication . Tiago, Daniel; Laizé, Vincent; Cancela, Leonor; Aureliano, M.Vanadium, a trace metal known to accumulate in bone and to mimic insulin, has been shown to regulate mammalian bone formation using in vitro and in vivo systems. In the present work, short- and long-term effects of metavanadate (containing monomeric, dimeric, tetrameric and pentameric vanadate species) and decavanadate (containing decameric vanadate species) solutions on the mineralization of a fish bone-derived cell line (VSa13) were studied and compared to that of insulin. After 2 h of incubation with vanadate (10 μM in monomeric vanadate), metavanadate exhibited higher accumulation rates than decavanadate (6.85±0.40 versus 3.95±0.10 μg V/g of protein, respectively) in fish VSa13 cells and was also shown to be less toxic when applied for short periods. In longer treatments with both metavanadate and decavanadate solutions, similar effects were promoted: stimulation of cell proliferation and strong impairment (75%) of extracellular matrix (ECM) mineralization. The effect of both vanadate solutions (5 μM in monomeric vanadate), on ECM mineralization was increased in the presence of insulin (10 nM). It is concluded that chronic treatment with both vanadate solutions stimulated fish VSa13 cells proliferation and prevented ECM mineralization. Newly developed VSa13 fish cells appeared to be appropriate in the characterization of vanadate effects on vertebrate bone formation, representing a good alternative to mammalian systems.
- Alternatively spliced transcripts of Sparus aurata insulin-like growth factor 1 are differentially expressed in adult tissues and during early developmentPublication . Tiago, Daniel; Laizé, Vincent; Cancela, LeonorSpliced variants of insulin-like growth factor 1 (IGF-1), a small peptide with a critical role in metabolism and growth, have been identified in various vertebrate species. However, despite recent functional data in mammalian systems suggesting specific roles (e.g. in muscle formation) for their pro-peptides and/or E domains, their function remains unclear. In this study, three alternatively spliced variants of Sparus aurata proIGF-1 (1a, 1b, and 1c) were identified and their expression analyzed. In adult fish, IGF-1 gene expression was observed in various soft tissues (highest levels in liver) and calcified tissues, with IGF-1c being always the most expressed isoform. In developing larvae, each isoform presented a specific pattern of expression, characterized by different onset and extent and consistent with a possible role of IGF-1a and 1b during early post-hatching events (e.g. bone or muscle formation), while IGF-1c would be rather involved in early larvae formation but probably acts in concerted action with other isoforms at later stages. We also propose that, in adults, IGF-1a and 1b isoforms may have a local action, while isoform 1c would assume a systemic action, as its mammalian counterpart. This hypothesis was further supported by in silico analysis of isoform distribution, revealing that only IGF-1c/Ea isoform has been conserved throughout evolution and that other fish isoforms (i.e. 1a and 1b) may be associated with mechanisms of osmoregulation. We finally propose that IGF-1 variants may exhibit different modes of action (systemic or local) and may be involved in different developmental and adaptive mechanisms.
- Complete larval development of the hermit crabs Clibanarius aequabilis and Clibanarius erythropus (Decapoda : Anomura : Diogenidae), under laboratory conditions, with a revision of the larval features of genus ClibanariusPublication . Bartilotti, Catia; Calado, Ricardo; dos Santos, AntoninaThe complete larval development (four zoeae and one megalopa) of Clibanarius aequabilis and C. erythropus, reared under laboratory conditions, is described and illustrated. The larval stages of the two northeastern Atlantic Clibanarius species cannot be easily differentiated. Their morphological characters are compared with those of other known Clibanarius larvae. The genus Clibanarius is very homogeneous with respect to larval characters. All Clibanarius zoeae display a broad and blunt rostrum, smooth abdominal segments and an antennal scale without a terminal spine. Beyond the second zoeal stage, the fourth telson process is present as a fused spine, and the uropods are biramous. In the fourth larval stage all species display a mandibular palp. The Clibanarius megalopa presents weakly developed or no ocular scales, symmetrical chelipeds, apically curved corneous dactylus in the second and third pereiopods, and 5-11 setae on the posterior margin of the telson. Apart from the number of zoeal stages, Clibanarius species may be separated, beyond the second zoeal stage, by the telson formula and the morphology of the fourth telson process.
- The artisanal fishery for muricid gastropods (banded murex and purple dye murex) in the Ria Formosa lagoon (Algarve coast, southern Portugal)Publication . Vasconcelos, Paulo; Carvalho, Susana; Castro, Margarida; Gaspar, MiguelThe artisanal fishery for muricid gastropods in the Ria Formosa lagoon (Algarve coast, southern Portugal) is a locally important fishing activity because the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) are greatly appreciated seafoods with high commercial value in the Portuguese seafood market. An integrated study was implemented to monitor the muricid gastropod fishery with the artisanal fishing gear ("wallet-line") through monthly experimental fishing operations carried out during one year. The aim Was to describe the fishing operations and fishing gear, to estimate the fishing yield, to characterise the target species catch composition, and to identify by-catch species and discards. The "wallet-line" is neither a species-specific nor a size-selective fishing gear, because the catches comprised a variety of by-catch species and a high proportion of commercially under-sized target species. The vast majority of the by-catch is discarded immediately on board, so mortality is presumably negligible. The CPUE of both target species and by-catch species decreased during consecutive fishing days, mainly due to declining bait attraction. Considering the overall information gathered on this fishing activity, some management measures are proposed for this artisanal fishery, which might ultimately contribute to the long-term Sustainable exploitation of the fishing resource.
- Periodicity of propagule expulsion and settlement in the competing native and invasive brown seaweeds, Cystoseira humilis and Sargassum muticum (Phaeophyta)Publication . Engelen, Aschwin; Espirito-Santo, C.; Simões, T.; Monteiro, C. A.; Serrão, Ester; Pearson, G. A.; Santos, RuiDense stands of the invasive species Sargassum muticum (Yendo) Fensholt develop in tidal pools close to its southern distributional limit in Europe, the southwest coast of Portugal. Along this coast, sheltered tidal pools form a specific habitat in which colonization occurs. Invaded pools are originally inhabited by Cystoseira humilis Kützing. Differences in gamete release between the competing native and alien species might be important for the initial settlement and further spread of the invader. Therefore, we tested whether egg expulsion and embryo settlement in both species had the same timing with respect to lunar and tidal cycles. For more than 2 months during the reproductive season egg expulsion and embryo release were monitored daily for each species. Egg expulsion in S. muticum showed a broadly semilunar periodicity peaking around full and new moon (spring tides), when low tides take place in the morning/evening. In contrast, C. humilis egg expulsion showed an asymmetric semilunar-to-lunar periodicity peaking around waning quarter moon, when low tides occur around midday. Embryo settlement detected in pools was low for both species and less periodic. Phase differences in expulsion events between the two species with respect to the semilunar cycle suggest that cues other than the moon are involved in their timing. Our observations suggest that variations in physiological mechanisms and/or environmental conditions result in different patterns of egg expulsion between the two species. This might have consequences for fertilization success, gamete dispersal and survival. It was further found that peaks in egg expulsion and embryo release (i.e. settlement) in S. muticum were much more synchronous at a site in northern Portugal compared with a site close to the current southern distributional limit in south-west Portugal, possibly as a consequence of thermal stress experienced in the south.
- Assessment of ecological quality status of rocky shores in South Portugal and implementation of water framework directivePublication . Singh, Charu Lata; Newton, Alice; Neto, João Miguel MagalhãesComo foi estipulado pela Directiva Quadro da Água da União Europeia, a riqueza específica de macroalgas, a composição e a cobertura de espécies oportunistas na zona intertidal em costas rochosas, foram usados para avaliar o estado de qualidade ecológica (EQS) em águas costeiras do sul de Portugal. A ferramenta P-MarMAT foi desenvolvida para as condições em Portugal e uma lista reduzida de espécies (RSL) definida para a zona sul do país, que foi usada para definir o EQS em termos de rácio de qualidade ecológica (EQR). Como as costas rochosas do sul de Portugal não foram estudadas durante o exercicio de intercalibração, três locais de estudo, nomeadamente, Castelejo, Ingrina, e Lagos foram seleccionados para avaliar o EQS em costas rochosas. Através da metodologia P-MarMAT e da análise de componentes principais (PCA), pode-se justificar que o estado de qualidade ecológica do Castelejo e Ingrina é compativel com o gradiente ambiental. Somente para duas das amostras da Ingrina (Dezembro 2007 e Janeiro de 2008), não foi possível obter uma correlação entre o EQR e o gradiente ambiental dado pelos parâmetros físico-químicos e os elementos de qualidade biológica desta massa de água costeira. Uma forte contribuição positiva da riqueza específica e uma forte resposta negativa da cobertura de algas oportunistas para o EQR foi dominante. A proporção de algas verdes e de oportunistas demonstram um comportamento negativo semelhante enquanto a proporção de algas vermelhas mostra uma relação positiva. A inclusão da descrição da costa rochosa não melhora significativamente 0 EQR. Como o Castelejo é um local com pouca perturbação, os valores limite das métricas pode ter de ser afinada, para que o seu EQS mude de moderado para bom. Os valores limite para a descrição da costa rochosa também deveria ser modificada, ou um sistema diferentes de pontuação deveria ser aplicado para corrigir o EQR para a natural variação ambiental.
- Parkinson's disease: substrate proteins and E2 enzymes involved in Parkin pathwayPublication . Guerreiro, Patrícia I. da Silva; Johnston, Jennifer A.Parkinson’s disease (PD) is one of the most common age-related neurodegenerative disorders, resulting from the degeneration and death of dopaminergic neurons and the consequent loss of a neurotransmitter dopamine. The molecular genetics of this process remains unclear but studies from PD inherited forms identified a mutated Parkin gene as responsible for almost 50% of autosomal-recessive juvenile parkinsonism (AR-JP). To better understand parkin’s role in PD the present study focused on several cellular assays using HEK-293 cells, mice brain samples and human cortical cells, evaluating the interaction of parkin protein with p38 and Eps15, two potential protein substrates, and five E2 enzymes UbcH2, UbcH5, UbcH6, UbcH7 and UbcH10. The interaction of p38 and Eps15 protein with parkin was demonstrated in some particularly assays. The results highlight the importance of tagged parkin, with Flag or GST epitopes, to analyze specific interaction between p38 and Eps15 proteins. UbcH2, UbcH7 and UbcH10 E2 enzymes interact with parkin protein and open new hypothesis for parkin’s function in several cellular processes. Initially based on some published results, this study reveals new important lines in the research of parkin protein pathway.
- Defining sea grass ecological status in Ria Formosa under the european water framework directivePublication . Marin, Patricia Garcia; Cabaço, Susana Isabel dos Santos; Newton, AliceThe Water Framework Directive (WFD) aims to achieve a good quality status of all the European water bodies by the year 2015. The Directive demands that the ecological status is quantified based primarily on biological indicators. Seagrasses are one of the biological quality elements (BQE) to be used in defining the ecological quality status (EQS) of transitional and coastal waters. This thesis focuses on the application of seagrasses as BQE to assess the ecological status of the Ria Formosa lagoon. The sites of Ponte and Ramalhete, already registered as part of the European list of inter-calibration sites for the WFD, were assessed. The metrics established by the Directive for this BQE, i.e. the taxonomic composition and the seagrass abundance (bed area extent and shoot density), were determined and compared with the reference conditions. The Ponte and Ramalhete sites had a mean score of Ecological Quality Ratio (EQR) of 0.90 and of 0.97, respectively (both scores correspond to high ecological status). The main difference resulted from the lost of one seagrass species in the Ponte site. As a result Ria Formosa was considered at high ecological status using the seagrass biological quality element. However the classification provided by seagrasses was slightly higher than the classification obtained by other studies considering other BQE (phytoplankton, nutrients). This study was the first attempt to establish the EQS of Ria Formosa using seagrass as a BQE. Further research is required to establish a more accurate and integrated EQS of the Ria Formosa lagoon.