Browsing by Author "Carvalho, M. Fátima"
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- Arbuscular mycorrhizal fungi are more efficient than chemical fertilisers in the production of essential oils of common thyme (Thymus vulgaris )Publication . Oliveira, Rui S.; Moreira, Vanessa; Nunes, Mafalda; Rocha, Inês; Carvalho, M. Fátima; Vosátka, Miroslav; Cavaleiro, Carlos; Salgueiro, Lígia; Freitas, HelenaCommon thyme is an aromatic plant with medicinal, cosmetics and culinary uses. Due to its antimicrobial, antioxidant/antiradical and antitumor activity the essential oils of common thyme are in great demand (Nikolić et al., 2014). A significant part of the production of aromatic plants relies on the use of chemical fertilisers, which when applied in large scale can have significant environmental consequences (Malik et al., 2011). Arbuscular mycorrhizal fungi (AMF) are a group of soil microorganisms that forms mutualistic symbioses that can benefit plants by improving the uptake of mineral nutrients, mineralising organic nutrients and conferring drought resistance (Oliveira et al., 2005).AMF have the potential to be inoculatedin the production of common thyme as an ecotechnological tool to reduce the input of chemicals fertilisers.
- Bioprospecting for cellulose-degrading microorganismsPublication . Almeida, Liliana; Alexandrino, Diogo; Oliveira, Rui S.; Carvalho, M. Fátima; Freitas, Marisa; Freitas, MarisaCellulose, a complex polysaccharide, is one of the main components of plant and algae biomass and therefore the most abundant polymer found in nature, serving as a significant carbon source in various ecosystems. Bioprospecting for cellulolytic microbes is a promising strategy for discovering potential biocatalysts for the hydrolysis of lignocellulosic materials, including residues. This work aims to assess the cellulolytic potential of microbial isolates (bacteria and fungi) sourced from diverse environments and to establish a synthetic microbial consortium capable to enhance the management of cellulosic waste. The experimental approach encompasses biodegradation assays coupled with optimized colorimetric methods, to estimate cellulose consumption (Congo Red assay) and the concomitant production of oligomeric/monomeric sugars (Dinitrosalicylic acid assay). For bacterial strains, these biodegradation assays involve batch incubations in minimal liquid medium supplied with cellulose as the sole carbon source, while solid medium is being used for fungi. Both assays are being run under mesophilic temperatures (28-30 ºC) and aerobic conditions. Upon achieving a final selection, strains exhibiting the best cellulose degradation performances will be assembled into a synthetic consortium that will be evaluated for their cellulose degradation capability. Future steps will also include phylogenetic identification of the cellulose degrading isolates through 16S and ITS rRNA gene sequence analysis. This study has the potential to identify novel cellulolytic microbes, highlighting the substantial role microorganisms play in ecosystem processes and their diverse applications in biotechnology.
- 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.
- Exposição ocupacional a fungos: um estudo de caso na indústria transformadora da cortiçaPublication . Rocha, Ricardo; Neves, Maria Paula; Girão, Mariana; Carvalho, M. Fátima; Oliveira, Rui S.; Santos, JoanaOccupational exposure to fungi in the cork industry is responsible for several respiratory problems and can be influenced by factors such as automation level of the production process, type of ventilation, storage conditions and cooking times of cork boards. Thus, the main objective of this study was to evaluated and identified fungal species existing in the air and surfaces of slicing and punching workplaces in cork small and medium-sized companies (SMEs). Air and surfaces samples were collected in five cork SMEs, included a total of eighteen workplaces. The collection of pure fungal colonies and their respective isolation was performed by plaque scoring technique, and DNA extraction, followed by the PCR technique and sequencing. The fungi identified were Penicillium glabrum and Neurospora spp. Improve the ventilation and storage conditions, as well as increase automation level of the production can reduce the risk of occupational exposure in SMEs.
- Microbial degradation of Sodium Trifluoroacetate under aerobic and anaerobic conditionsPublication . Alexandrino, Diogo A. M.; Oliveira, Rui S.; Carvalho, M. FátimaThe extensive use of hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) as environmental acceptable alternatives to chlorofluorocarbons (CFCs) has been responsible for the introduction in the environment of significant amounts of Trifluoroacetate (TFA). Specifically, TFA is produced by the atmospheric breakdown of HCFC-123, HCFC-124, HFC-134a and HFO-1234yf, which undergo oxidative, photolytic and hydrolytic reactions to generate the compound. TFA is a highly persistent, water soluble and extremely stable fluorinated compound, that tends to accumulate in low-streamed aquatic environments, with marine ecosystems as its ultimate environmental sink. Although it does not exert considerable toxicological effects neither in microbial communities, nor in aquatic organisms, it reveals a mild toxicity regarding plants (Boutonnetet al. , 1999). There are no reports on the aerobic biodegradation of TFA, but the mineralisation of the compound by anaerobic methanogenic bacteria was demonstrated in few studies (Visscher, et al ., 1994; Kim et al., 2000).