ESS - CM - Ciências Morfológicas
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- Harmful cyanobacterial toxic blooms in waste stabilization pondsPublication . Barros, Piedade; Martins, RosarioA coccoid picocyanobacterium Synechocystis sp. (0.6-2 µm of cell diameter) was found to be dominant during summer period in the experimental wastewater stabilisation pond of Marrakesh. The taxonomy of this isolated strain was confirmed by electron microscope study. The general patterns of ultrastructure and the mode of cell division resemble Chroococcales. The cyanobacterium strain was axenic and cultured on both inorganic Z8 and BG13 media. Mammalian toxicity was confirmed by mice bioassay. The major sympton of poisoning was severe diarrhoea. Histopathological study shows a slight hepatotoxicosis associated with a pronounced change in the intestinal mucosa which shows swelling and destruction of villi epithelium and shedding of enterocytes into the lumen. Although slow, these kinds of poisoning are comparable to those induced by okadiac acid intraperitoneal mice injection (diarrhetic shellfish poisoning “DSP” toxins). By using the enzyme-linked immunosorbent assay (ELISA), the amount of hepatotoxins “microcystins” was determined. The result shows that Synechocystis can produce a small amount of total microcystine [an average of 15 µg-1 dry weight corresponding to 20 ng(109cell)-1]. These findings lead us to consider Synechocystis as both a potent neurotoxin and hepatotoxin producer. Because of the confirmed cyanobacterium toxicity, an eventual ecological implication should be considered. However, a toxic chronic test experiment on Daphnia was simultaneously carried out. Juvenile D. magna (less than 24 hours old), were fed three concentrations (104 , 106 , 108 cells / ml) of Synechocystis. A group of organisms fed with Chlorella vulgaris (3. 105 cells/ml) and another group without food, were studied as control treatments. Only animals cultured with 104 cells/ml of cyanobacterium survived at 80% until the end of the test (21 days). Reproduction and normal growth occurred in control treatments fed with Chlorella vulgaris and the group fed with the lowest concentration of Synechocystis. One-way ANOVA statistical analyses show significant differences in Daphnia survival and growth, between treatments with and without Synechocystis and between treatments with and without food. In terms of this study, there is evidence that toxic picocyanobacteria blooms occurring in wastewater stabilization ponds of Marrakesh, could have harmful repercussions on zooplanktonic, bacteria and other algae communities. Consequently, this will constitute a possible hindrance for sewage self-purification process and system treatment performance. In addition, the reuse of such treated wastewater effluent for irrigation will constitute an additional, potent, health hazard for animals and human’s. Keywords Chlorella; daphnia; microcystins; picocyanobacteria; synechocystis; wastewater.
- Isolation, characterization and quantification of microcystins (heptapeptides hepatotoxins) in Microcystis aeruginosa dominated bloom of Lalla Takerkoust lake–reservoir (Morocco)Publication . Martins, RosarioThis paper presents the first data on the identification, characterization and quantification of microcystins isolated from both an extract of a cyanobacteria natural bloom, collected from a eutrophic Moroccan reservoir (Lalla Takerkoust, Marrakesh) and an isolated strain cultivated under laboratory conditions. The isolation and purification of toxins was performed by reverse phase HPLC and then characterized by amino acid analysis and fast atom bombardment mass spectrometry (FAB-MS). Chemical characterization of the toxins from the bloom revealed variants of microcystins such as Mcyst-LR, Mcyst-RR, Mcyst-YR and [D-Asp3]Mcyst-LR. However, the Microcystis aeruginosa strain produced only Mcyst-RR. Using an ELISA assay the total microcystin contents of eight bloom samples collected from 1994 to 1997 ranged from 0.7 to 8.8 μg/mg of lyophilized material. The two isolated Microcystis strains contained higher amounts of microcystins (0.65 μg/ mg of dry weight) than the Pseudanabaena strains (0.021 μg/mg of dry weight). Our results show that the presence of cyanobacteria toxins in water used for drinking in a North African country may be regarded as an health hazard. These results are a contribution to the knowledge of the biogeography of toxic cyanobacteria and their toxins, namely in north African countries.
- Alterações anatómicas induzidas pela idade na coluna vertebral: intervenção para melhoria da saúde da comunidadePublication . Ribas, Jorge; Ribas, C.; Prudêncio, CristinaO aumento do envelhecimento da população implica uma crescente importância na implementação da política de cuidados de saúde primários. O envelhecimento leva a profundas alterações na morfologia da coluna vertebral do indivíduo. Estas alterações não estão ainda devidamente caracterizadas pelo que é necessário estudar e tipificar quais as mudanças induzidas pela idade. Desta forma será possível avaliar de que forma o patológico se poderá enquadrar num padrão normal de envelhecimento.
- Promoção da saúde da mulher com incontinência urinária: validação de instrumentos de avaliaçãoPublication . Ribas, C.; Ribas, Jorge; Prudêncio, CristinaA incontinência urinária (IU) feminina é um importante problema de saúde pública, quer pela sua prevalência, quer pelo elevado impacto físico, psíquico e social na vida da doente. Embora a prevalência da IU tenha sido descrita em vários trabalhos como mais elevada em mulheres idosas, esta perturbação atinge igualmente mulheres jovens e de meia-idade ou seja no ciclo da vida activa. Desta forma constitui um handicap na condição da mulher quer ao nível profissional, familiar e/ou sexual.
- Toxicity assessment of crude and partially purified extracts of marine Synechocystis and Synechococcus cyanobacterial strains in marine invertebratesPublication . Martins, Rosario; Fernandez, Nuria; Beiras, Ricardo; Vasconcelos, VítorAmong the Cyanoprokaryota, the genera Synechocystis and Synechococcus have rarely been studied with respect to potential toxicity. This is particularly true with marine environments where studies about the toxicity of cyanobacteria are restricted to filamentous forms at the warmer temperate and tropical regions and also to filamentous forms at cold seas such as the Baltic Sea. In this study, we describe the effects of cyanobacterial strains of the Synechocystis and Synechococcus genera isolated from the marine coast of Portugal, on marine invertebrates. Crude and partially purified extracts at a concentration of 100 mg/ml of freeze-dried material of the marine strains were tested for acute toxicity in nauplii of the brine shrimp Artemia salina, in the rotifer Brachionus plicatillis and in embryos of the sea urchin Paracentrotus lividus and the mussel Mytilus galloprovincialis. The cyanobacterial extracts, especially the crude extract, had an impact on A. salina nauplii. No significant toxic effects were registered against the rotifer. A negative impact of all strains was recorded on the embryonic development of the sea urchin, with toxic effects resulting in an inhibition of embryogenesis or development of smaller larvae. To the mussel embryos, the effects of cyanobacterial extracts resulted in a complete inhibition of embryogenesis. The results of all assays indicate that Synechocystis and Synechococcus marine strains contained toxic compounds to marine invertebrates.
- Antimicrobial and cytotoxic assessment of marine cyanobacteria - synechocystis and synechococcusPublication . Martins, Rosario; Ramos, Miguel; Herfindal, Lars; Sousa, José; Skærven, Kaja; Vasconcelos, VítorAqueous extracts and organic solvent extracts of isolated marine cyanobacteria strains were tested for antimicrobial activity against a fungus, Gram-positive and Gram-negative bacteria and for cytotoxic activity against primary rat hepatocytes and HL-60 cells. Antimicrobial activity was based on the agar diffusion assay. Cytotoxic activity was measured by apoptotic cell death scored by cell surface evaluation and nuclear morphology. A high percentage of apoptotic cells were observed for HL-60 cells when treated with cyanobacterial organic extracts. Slight apoptotic effects were observed in primary rat hepatocytes when exposed to aqueous cyanobacterial extracts. Nine cyanobacteria strains were found to have antibiotic activity against two Gram-positive bacteria, Clavibacter michiganensis subsp. insidiosum and Cellulomonas uda. No inhibitory effects were found against the fungus Candida albicans and Gram-negative bacteria. Marine Synechocystis and Synechococcus extracts induce apoptosis in eukaryotic cells and cause inhibition of Gram-positive bacteria. The different activity in different extracts suggests different compounds with different polarities.
- A avaliação de stress em saúde ocupacional numa equipa de urgência: um estudo pilotoPublication . Ribas, Cláudia; Ribas, Jorge; Abreu, Sofia; Fonte, Rosália; Moucho, Marina; Montenegro, Nuno; Prudêncio, CristinaO presente estudo constituiu um estudo preliminar que se debruçou sobre a avaliação do stress em Saúde Ocupacional em profissionais que integram o serviço de urgência de Obstétrica do Hospital de S. João no Porto. Esta avaliação visa a elaboração de estratégias que contribuam para a maximização dos cuidados de saúde e está diretamente associada à tríada recursos humanos, materiais e satisfação do utente.
- Hábitos e comportamentos associados ao uso de antibióticos: A autonomia individual versus a saúde da comunidadePublication . Prudêncio, Cristina; Ferraz, Ricardo; Vieira, Mónica; Ribas, Cláudia; Ribas, Jorge; Fonte, Rosália; Fernandes, RubenA resistência a drogas é um dos graves problemas de saúde atual embora possa ser considerada uma resposta natural devida à pressão seletiva da droga. Esta resposta é no entanto exacerbada por vários fatores que incluem, abuso, subutilização ou má utilização, má adesão ao tratamento ou má qualidade das drogas disponíveis. Trata-se de um dos maiores desafios que enfrentam atualmente os profissionais de Saúde e a população em geral. A auto-medicação é um dos fatores que mais contribui para a resistência a antibióticos. No presente trabalho apresentamos um estudo preliminar onde foram avaliados os hábitos e comportamentos associados ao uso de antibióticos num grupo de Pais.
- Primary screening of the bioactivity of brackishwater cyanobacteria: toxicity of crude extracts to artemia salina larvae and paracentrotus lividus embryosPublication . Lopes, Viviana; Fernandez, Nuria; Martins, Rosario; Vasconcelos, VítorCyanobacteria are a diverse group of Gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against vertebrates, invertebrates, plants, microalgae, fungi, bacteria, viruses and cell lines. The aim of this study was to assess the toxic effects of aqueous, methanolic and hexane crude extracts of benthic and picoplanktonic cyanobacteria isolated from estuarine environments, towards the nauplii of the brine shrimp Artemia salina and embryos of the sea urchin Paracentrotus lividus. The A. salina lethality test was used as a frontline screen and then complemented by the more specific sea urchin embryo-larval assay. Eighteen cyanobacterial isolates, belonging to the genera Cyanobium, Leptolyngbya, Microcoleus, Phormidium, Nodularia, Nostoc and Synechocystis, were tested. Aqueous extracts of cyanobacteria strains showed potent toxicity against A. salina, whereas in P. lividus, methanolic and aqueous extracts showed embryo toxicity, with clear effects on development during early stages. The results suggest that the brackishwater cyanobacteria are producers of bioactive compounds with toxicological effects that may interfere with the dynamics of invertebrate populations.
- Are known cyanotoxins involved in the toxicity of picoplanktonic and filamentous north atlantic marine cyanobacteria?Publication . Frazão, Bárbara; Martins, Rosario; Vasconcelos, VítorEight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.