Antimicrobial and cytotoxic assessment of marine cyanobacteria - synechocystis and synechococcus

Aqueous 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.

Primary screening of the bioactivity of brackishwater cyanobacteria: toxicity of crude extracts to artemia salina larvae and paracentrotus lividus embryos

Cyanobacteria 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.

Music and drama in primary schools in the Madeira Island - Narratives of ownership and leadership

Este artigo foi uma das publicações resultantes do projeto financiado pela FCT "Música e Drama no 1º ciclo do Ensino básico – o caso da Região Autónoma da Madeira" (PTDC/CED/72112/2006).

Performance management in primary healthcare services: evidence from a field study

Health services

The Digital Textbook: Methodological and Didactic Challenges for Primary School

The potentialities of ICT in education bring about changes in the teaching and learning methodologies, in the places where you learn and in the way you learn. This demands a reflection not only on the ways of learning, but also on the support resources, so that learning can take place and, of course, it is indispensable to understand the teachers’ answer to the digital challenges. Thus, the purpose of this analysis is to reflect about technological trends in an educational context and their underlying models by analyzing the role played by digital textbooks in Portugal in an innovating context. This way, we intend to contribute to an educational policy as we plan to relate the teachers’ training to the increasing development of the digital textbooks and we also intend to contribute to the understanding of a didactic resource which is closely related to the learning processes which resort to advanced technology.

Strategies to assess web resources credibility: results of a case study in primary and secondary schools from Portugal

In this paper, three approaches for the assessment of credibility in a web environment will be presented, namely the checklists model, the cognitive authority model and the contextual model. This theoretical framework was used to conduct a study about the assessment of web resources credibility among a sample of 195 students, from elementary and secondary schools in a municipality in Oporto district (Portugal). The practices that young people and children claim to use regarding the use of criteria for web resources selection will be presented. In addition, these results will be discussed and compared with the perceptions that these respondents have demonstrated for the use of criteria to establish or assess authorship, originality, or information resources structure. These results will be also discussed and compared with the perceptions that these respondents have demonstrated for the elements that make up each of these criteria.