Publications by authors named "Sara Bettencourt"

7 Publications

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Marine litter: A review of educative interventions.

Mar Pollut Bull 2021 Jul 12;168:112446. Epub 2021 May 12.

Department of Science and Technology, Portuguese Distance Learning University, Lisbon, Portugal; CENSE - Center for Environmental and Sustainability Research, School of Science and Technology, NOVA University of Lisbon, Lisbon, Portugal.

Marine litter is claimed to be one of the most meaningful environmental crises of the century. Education that supports behavior change is a tool to tackle this problem. However, there is a lack of research linking educational initiatives and marine litter issues. A literature review was conducted through a bibliometric and content analysis to explore the state of knowledge regarding educational actions. The results revealed that 2019 was the year with the highest number of publications and that 83.4% of the documents were collaborative efforts. Concerning educational approaches, hands-on and technological activities are being explored to raise awareness and stimulate behavior change. Students and questionnaires represent, respectively, the most common audience and evaluating method. More integrative actions and respective long-term methodological triangulation evaluation were identified as necessary in future studies. This paper is expected to contribute to innovative knowledge in the area by identifying the main gaps in the literature.
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http://dx.doi.org/10.1016/j.marpolbul.2021.112446DOI Listing
July 2021

Single Cell Oil Production by Oleaginous Yeasts Grown in Synthetic and Waste-Derived Volatile Fatty Acids.

Microorganisms 2020 Nov 17;8(11). Epub 2020 Nov 17.

CBMA-Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.

Four yeast isolates from the species-, , , and -previously selected by their oleaginous character and growth flexibility in different carbon sources, were tested for their capacity to convert volatile fatty acids into lipids, in the form of single cell oils. Growth, lipid yields, volatile fatty acids consumption, and long-chain fatty acid profiles were evaluated in media supplemented with seven different volatile fatty acids (acetic, butyric, propionic, isobutyric, valeric, isovaleric, and caproic), and also in a dark fermentation effluent filtrate. Yeasts and attained lipid productivities of more than 40% (/), mainly composed of oleic (>40%), palmitic (20%), and stearic (20%) acids, both in synthetic media and in the waste-derived effluent filtrate. These isolates may be potential candidates for single cell oil production in larger scale applications by using alternative carbon sources, combining economic and environmental benefits.
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http://dx.doi.org/10.3390/microorganisms8111809DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7698568PMC
November 2020

Modified high-throughput Nile red fluorescence assay for the rapid screening of oleaginous yeasts using acetic acid as carbon source.

BMC Microbiol 2020 03 14;20(1):60. Epub 2020 Mar 14.

CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.

Background: Over the last years oleaginous yeasts have been studied for several energetic, oleochemical, medical and pharmaceutical purposes. However, only a small number of yeasts are known and have been deeply exploited. The search for new isolates with high oleaginous capacity becomes imperative, as well as the use of alternative and ecological carbon sources for yeast growth.

Results: In the present study a high-throughput screening comprising 366 distinct yeast isolates was performed by applying an optimised protocol based on two approaches: (I) yeast cultivation on solid medium using acetic acid as carbon source, (II) neutral lipid estimation by fluorimetry using the lipophilic dye Nile red.

Conclusions: Results showed that, with the proposed methodology, the oleaginous potential of yeasts with broad taxonomic diversity and variety of growth characteristics was discriminated. Furthermore, this work clearly demonstrated the association of the oleaginous yeast character to the strain level, contrarily to the species-level linkage, as usually stated.
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http://dx.doi.org/10.1186/s12866-020-01742-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071767PMC
March 2020

Isolation of Vacuoles from the Leaves of the Medicinal Plant Catharanthus roseus.

Methods Mol Biol 2018 ;1789:81-99

CIBIO/InBIO-Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal.

The isolation of vacuoles is an essential step to unravel the important and complex functions of this organelle in plant physiology. Here, we describe a method for the isolation of vacuoles from Catharanthus roseus leaves involving a simple procedure for the isolation of protoplasts, and the application of a controlled osmotic/thermal shock to the naked cells, leading to the release of intact vacuoles, which are subsequently purified by density gradient centrifugation. The purity of the isolated intact vacuoles is assayed by microscopy, western blotting, and measurement of vacuolar (V)-H-ATPase hydrolytic activity. Finally, membrane functionality and integrity is evaluated by measuring the generation of a transtonoplast pH gradient by the V-H-ATPase and the V-H-pyrophosphatase, also producing further information on vacuole purity.
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http://dx.doi.org/10.1007/978-1-4939-7856-4_7DOI Listing
February 2019

Isolation of Cells Specialized in Anticancer Alkaloid Metabolism by Fluorescence-Activated Cell Sorting.

Plant Physiol 2016 08 29;171(4):2371-8. Epub 2016 Jun 29.

CIBIO/InBIO-Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal (S.B., T.M.-C., J.G.G., M.S.); Instituto de Investigação e Inovação em Saúde, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal (I.C., A.L.G., P.D.);Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal (I.C., M.S.);Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal (R.G., T.L., C.A., C.B., N.P.M.);REQUIMTE/Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal (P.A., P.V.); andREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal (I.M.V., J.A.R.)

Plant specialized metabolism often presents a complex cell-specific compartmentation essential to accomplish the biosynthesis of valuable plant natural products. Hence, the disclosure and potential manipulation of such pathways may depend on the capacity to isolate and characterize specific cell types. Catharanthus roseus is the source of several medicinal terpenoid indole alkaloids, including the low-level anticancer vinblastine and vincristine, for which the late biosynthetic steps occur in specialized mesophyll cells called idioblasts. Here, the optical, fluorescence, and alkaloid-accumulating properties of C. roseus leaf idioblasts are characterized, and a methodology for the isolation of idioblast protoplasts by fluorescence-activated cell sorting is established, taking advantage of the distinctive autofluorescence of these cells. This achievement represents a crucial step for the development of differential omic strategies leading to the identification of candidate genes putatively involved in the biosynthesis, pathway regulation, and transmembrane transport leading to the anticancer alkaloids from C. roseus.
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http://dx.doi.org/10.1104/pp.16.01028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972299PMC
August 2016

Protoplast Transformation as a Plant-Transferable Transient Expression System.

Methods Mol Biol 2016 ;1405:137-48

Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.

The direct uptake of DNA by naked plant cells (protoplasts) provides an expression system of exception for the quickly growing research in non-model plants, fuelled by the power of next-generation sequencing to identify novel candidate genes. Here, we describe a simple and effective method for isolation and transformation of protoplasts, and illustrate its application to several plant materials.
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http://dx.doi.org/10.1007/978-1-4939-3393-8_13DOI Listing
November 2016

Identification of phenolic compounds in isolated vacuoles of the medicinal plant Catharanthus roseus and their interaction with vacuolar class III peroxidase: an H₂O₂ affair?

J Exp Bot 2011 May 28;62(8):2841-54. Epub 2011 Feb 28.

Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS (CSIC), PO Box 164, E-30100 Campus University Espinardo (Murcia), Spain.

Class III peroxidases (Prxs) are plant enzymes capable of using H(2)O(2) to oxidize a range of plant secondary metabolites, notably phenolic compounds. These enzymes are localized in the cell wall or in the vacuole, which is a target for secondary metabolite accumulation, but very little is known about the function of vacuolar Prxs. Here, the physiological role of the main leaf vacuolar Prx of the medicinal plant Catharanthus roseus, CrPrx1, was further investigated namely by studying its capacity to oxidize co-localized phenolic substrates at the expense of H(2)O(2). LC-PAD-MS analysis of the phenols from isolated leaf vacuoles detected the presence of three caffeoylquinic acids and four flavonoids in this organelle. These phenols or similar compounds were shown to be good CrPrx1 substrates, and the CrPrx1-mediated oxidation of 5-O-caffeoylquinic acid was shown to form a co-operative regenerating cycle with ascorbic acid. Interestingly, more than 90% of total leaf Prx activity was localized in the vacuoles, associated to discrete spots of the tonoplast. Prx activity inside the vacuoles was estimated to be 1809 nkat ml(-1), which, together with the determined concentrations for the putative vacuolar phenolic substrates, indicate a very high H(2)O(2) scavenging capacity, up to 9 mM s(-1). Accordingly, high light conditions, known to increase H(2)O(2) production, induced both phenols and Prx levels. Therefore, it is proposed that the vacuolar couple Prx/secondary metabolites represent an important sink/buffer of H(2)O(2) in green plant cells.
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http://dx.doi.org/10.1093/jxb/erq458DOI Listing
May 2011