ESS - CQB - Posters apresentados em eventos científicos
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Browsing ESS - CQB - Posters apresentados em eventos científicos by Subject "Actinobacteria"
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- Exploring actinobacterial diversity in Ruta graveolens: Phylogenetic identification and bioactive potential investigationPublication . Ferreira, Sílvia; Ribeiro, Inês; Oliveira, Rui S.; Carvalho, M. FátimaMedicinal plants and their components have been utilized in traditional medicine for centuries and have significantly influenced the development of modern medicine. Ruta graveolens, a Rutaceae medical plant, is known for its antibacterial, anti-inflammatory and cytotoxic properties. Actinobacteria are a rich source of compounds exhibiting diverse biological activities and potential therapeutic applications. The aim of this study was to perform the phylogenetic identification of a collection of actinobacterial strains previously isolated from R. graveolens and to investigate their bioactive potential. Actinobacterial strains previously isolated from stem, roots and leaves of R. graveolens were grown in Actinomycete Isolation Agar (AIA) or Starch-Casein-Nitrate-Agar (SCN). DNA from grown cultures was extracted and phylogenetically identified through 16S rRNA gene sequencing. For each strain, organic extracts were performed and used for the screening of antimicrobial activity, using the disk diffusion test, against four reference bacteria (Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Escherichia coli) and one yeast (Candida albicans). Thirty-two actinobacterial isolates were so far identified. Most of the strains was identified as Tsukamurella tyrosinosolvens, constituting 13 out of 32 isolates, followed by 8 Streptomyces sp., 7 Brevibacterium sediminis, 3 Microbacterium ginsengiterrae, and one Gordonia hydrophobica. The organic extracts obtained from each isolate were tested for their antimicrobial activity. Up to moment, no significant bioactivity was detected in the reference strains screened in this study. A collection of 32 actinobacterial strains was obtained from various parts of the medicinal plant R. graveolens. Though no relevant antimicrobial activity was yet found, extracts of these actinobacteria open new opportunities to explore their bioactive potentials with therapeutic applications.
- Exploring the biosurfactant potential of Actinobacteria isolated from Ruta graveolensPublication . Ferreira, Sílvia; Ribeiro, Inês; Oliveira, Rui S.; Carvalho, Maria de FátimaBiosurfactants are surface-active compounds known for their emulsifying properties and numerous advantages, including low environmental toxicity, eco-friendliness, biodegradability and acceptability. These molecules are amphiphilic, containing both hydrophilic and hydrophobic ends, allowing them to interact at the aqueous-non-aqueous interface. Bacterial biosurfactants are interesting due to their various fields of applications, including biomedicine, cosmetics, food, pharmaceutics, water treatment and oil recovery. Actinobacteria are an important group of microorganisms with high potential for producing different bioactive metabolites including antimicrobial, anticancer and other pharmaceutical compounds. Medicinal plants,such as Ruta graveolens, are a rich source of bioactive compounds, and the association of actinobacteria endophytes with such plants are an attractive source for bioprospecting for novel compounds with biomedical and industrial applications. The purpose of this study was to explore the biosurfactant activity of actinobacterial strains previously isolated from R. graveolens. Fifteen previously isolated actinobacterial strains were inoculated into 100 mL Erlenmeyer flasks containing 30 mL of Kim’s broth supplemented with 3% filtered olive oil as a hydrophobic carbon source. After two weeks, biosurfactant productionwas analyzed by measuring the emulsification activity. Eight out of the 15 actinobacterial strains showed emulsification activity. All results were compared with a positive control consisting of Triton X100 (1mg/ml), and a negative control consisting in Kim’s broth. Almost all strains that revealed positive activity are affiliated to the actinobacterial species Tsukamurella tyrosinosolvens (7/8), with one strain belonging to the species Microbacterium gisengiterae. Comparative analysis with the positive control (with an emulsification activity of 60%), indicated that 3/8 samples showed high emulsification activity (>40%), 1 showed moderate activity (37%) and 4/8 showed low/moderate activity (20-30%). The subsequent phases of this study will involve analyzing if the potential biosurfactant compounds can reduce the surface tension and if they can represent new molecules.
- Resistance of actinobacteria and rhizobia from wild Saharan plants to environmental stresses and their phosphate solubilization capacityPublication . Pereira, Adriana; Girão, Mariana; Fecih, Thinhinane; Carvalho, Fátima; Oliveira, Rui S.Plant growth promoting bacteria (PGPB) enhance plant development through various mechanisms such as the fixation of atmospheric nitrogen, production of siderophores and phosphate solubilization. This could be beneficial for the implementation of more sustainable agricultural practices. The objective of this study was to evaluate the effect of temperature and salinity variation as well as to evaluate the phosphate solubilization capacity of a collection of bacteria, originating from various sites in the Algerian Sahara Desert]. These sites are affected by abiotic stresses such as wide variations in temperature range and high salinity levels, so PGPB for inoculation in these soils need to be adaptable and withstand extreme conditions. To carry out this study, the bacteria were subjected to different temperatures and concentrations of NaCl. The phosphate solubilization capacity was evaluated, in the National Botanical Research Institute’s Phosphate Growth (NBRIP) medium. Overall, the tested bacteria did not solubilize phosphate, since no halos were observed around the bacterial colonies. The bacteria most tolerant to a wider range of temperatures and salinities and, therefore, most promising for inoculation in semi-arid and arid soils were Afipia sp. 61 and Afipia massiliensis 21, which showed significant growth in all studied conditions. In general, it was observed that most bacteria grow at temperatures and salinities, different from their common growth range.