Browsing by Author "Galhano, Victor"
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- Avaliação do potencial algicida/algistático de extractos de plantas em microalgas (Chlorophta e Cyanophyta)Publication . Barros, Sandra; Geraldes, Ana Maria; Ramos, Antonieta; Galhano, Victor; Fernandes, ConceiçãoDevido à eutrofização, os sistemas aquáticos podem apresentar um desenvolvimento excessivo de fitoplâncton e algas filamentosas, com a concomitante diminuição da qualidade da água.. Para mitigar os problemas ambientais e económicos resultantes, têm sido implementadas medidas que abrangem a aplicação de algicidas e a redução do input de nutrientes. Contudo, alguns algicidas convencionais apresentam certas limitações, já que são tóxicos, a sua eficiência é discutível, e apresentam persistência no ambiente. A utilização de extractos vegetais poderá ser uma alternativa aos algicidas convencionais. O objectivo deste trabalho foi testar a actividade algicida e/ou algistática de extractos de plantas, recolhidas em Bragança, em dois tipos de microalgas.
- Avaliação do potencial algicida/algistático de extractos vegetais em microalgas (Chlorophta e Cyanophyta)Publication . Barros, Sandra; Geraldes, Ana Maria; Ramos, A.; Galhano, Victor; Fernandes, Conceição
- Fatty acid characterization of cyanobacterial strains isolated from Vela lake and Mondego river rice fields (central-western, Portugal)Publication . Galhano, Victor; Santos, H.; Geraldes, Ana Maria; Figueiredo, Daniela R.; Crespí, António; Gomes-Laranjo, José; Peixoto, Francisco P.
- Fatty acid characterization of cyanobacterial strains isolated from vela lake and mondego river rice fields (central-western, Portugal)Publication . Galhano, Victor; Santos, Hugo; Geraldes, Ana Maria; Figueiredo, Daniela R.; Crespí, António; Gomes-Laranjo, José; Peixoto, Francisco P.It is know that cyanobacterial taxonomic groups are characterized by particular lipid patterns that can be used as their biological markers. The present study examined the fatty acid composition of nostocacean heterocystous cyanobacterial strains isolated from Central-western Portuguese freshwater shallow water bodies, namely Vela Lake and rice fields from Mondego River Basin. Morphological characterization showed that strains from Vela Lake belonged to Aphanizomenon gracile (strains UADFA16 and UADFA18), Aphanizomenon flos-aquae (strain UADFA15) and Anabaena cf. solitaria (strain UADFA14) species, whereas rice field strains belonged to Anabaena cylindrica (strain UTAD_A212) and Nostoc muscorum (strain UTAD_N213). Biochemical characterization inferred from lipid analysis showed that predominant fatty acid methyl esters (FAMEs) in the lipids of the strains were palmitic, oleic and α-linolenic, with trace amounts of myristic and C20 polyunsaturated FAMEs. To our knowledge, there is almost no information about lipid composition in freshwater cyanobacterial species living in different habitats in Portugal. Therefore, this limnological study is a contribution to our investigation on freshwater diazotrophic cyanobacteria.
- Searching for Algaecide or Algaestatic Effects of Several Plant Extracts on Phytoplankton: Preliminary ResultsPublication . Fernandes, Conceição; Barros, Sandra; Galhano, Victor; Geraldes, Ana MariaStudy Design: Experimental research. Place and Duration of Study: The cyanobacterium Anabaena cylindrica and the green alga Chlorella vulgaris were used as test strains to evaluate the effects of plant extracts on algal growth. All experiments were undertaken in the Agricultural School of Bragança - Polytechnic Institute, from September 2010 to July 2011. Methodology: Essential oils were obtained by means of hydrodistillation of the plants. The oils and the water that remained, after the hydrodistillation, were further used for the growth screening of Anabaena cylindrica and Chlorella vulgaris under axenic cultures. Both types of extracts were tested at different concentrations. The essential oil effects were evaluated by disc diffusion method and water extracts effects were evaluated in batch cultures. Results: Essential oils had an algaecide effect in all tested concentrations (1:1; 1:3; 1:4 and 1:10) for both algal strains. Contrarily, none of the water extracts evidenced a complete algaecide effect. Nevertheless, promising results were obtained with rosemary water extract since the highest concentrations (1:4) had an algaestatic effect on C. vulgaris. Conversely, the observed effects on A. cylindrica varied from cellular density decrease to an algaestatic effect. Therefore, the tested algal strains presented distinct responses to both extract types and concentrations. Conclusions: Comparing the different extracts’ activity, it can be concluded that essential oils mostly influenced algal growth.