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- Oligomerization Profile of Human Transthyretin Variants with Distinct AmyloidogenicityPublication . Frangolho, Ana; Correia, Bruno E.; Vaz, Daniela C.; Almeida, Zaida L.; Brito, Rui M. M.One of the molecular hallmarks of amyloidoses is ordered protein aggregation involving the initial formation of soluble protein oligomers that eventually grow into insoluble fibrils. The identification and characterization of molecular species critical for amyloid fibril formation and disease development have been the focus of intense analysis in the literature. Here, using photo-induced cross-linking of unmodified proteins (PICUP), we studied the early stages of oligomerization of human transthyretin (TTR), a plasma protein involved in amyloid diseases (ATTR amyloidosis) with multiple clinical manifestations. Upon comparison, the oligomerization processes of wild-type TTR (TTRwt) and several TTR variants (TTRV30M, TTRL55P, and TTRT119M) clearly show distinct oligomerization kinetics for the amyloidogenic variants but a similar oligomerization mechanism. The oligomerization kinetics of the TTR amyloidogenic variants under analysis showed a good correlation with their amyloidogenic potential, with the most amyloidogenic variants aggregating faster (TTRL55P > TTRV30M > TTRwt). Moreover, the early stage oligomerization mechanism for these variants involves stepwise addition of monomeric units to the growing oligomer. A completely different behavior was observed for the nonamyloidogenic TTRT119M variant, which does not form oligomers in the same acidic conditions and even for longer incubation times. Thorough characterization of the initial steps of TTR oligomerization is critical for better understanding the origin of ATTR cytotoxicity and developing novel therapeutic strategies for the treatment of ATTR amyloidosis.
- Preserving and hydrogel-matrixing the bioactive properties of aromatic medicinal halophytic herbs from the coastline of the Iberian PeninsulaPublication . Parracho, Tiago; Cruz, Pedro F.; Peralta, Claúdia C.; Silva, Cândida G.; Campos, Maria Jorge; Neves, Marta; Cordeiro, Rachel; Trindade, Daniela; Moura, Carla; Almeida, Zaida L.; Pereira, Cidália D.; Guimarães, Carla; Brito, Rui M. M.; Guerra, Mauro; Reboredo, Fernando; Veríssimo, Paula; Vaz, Daniela C.; Santos Ribeiro, VâniaEdible wild plants are part of the ethnobotanic heritage of a certain geographical area and are important sources of essential oils, antioxidants, minerals, and special flavours. Corema album (Portuguese crowberry), Crithmum maritimum (sea fennel), Eryngium maritimum (sea holly), Helichrysum italicum (curry plant) and Otanthus maritimus (cottonweed) wildly flourish along the sandy dunes of the coast of the Iberian Peninsula. These plants are locally known for their beneficial properties, with important value for food, cosmetics and/or medicinal applications. Hence, leaves of these endemic species were collected at four different locations and submitted to different preserving treatments (oven-drying, freezing, and freeze-drying). Acetonic extracts of the different plants submitted to the different post-harvesting treatments were analysed regarding their antioxidant capacities and phenolic contents. Plant extracts were also analysed by diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY-NMR). In general, freeze-drying was the best method of preserving plant minerals, antioxidants (~4 mgVCEAC/g fw) and polyphenols (~5 mgGAE/g fw). Minerals were quantified via energy-dispersive X-ray fluorescence spectrometry, and despite their location, all plants were rich in Ca, Cl, K, S and P. Hierarchical clustering and principal component analyses (PCA) pointed towards chemical/metabolic proximity between taxonomic families. Alginate hydrogels loaded with 0.1 % and 0.2 % (w/v) of extracts presented homogenous surface properties by scanning electron microscopy, good mechanical tensile strength (~30 MPa) and antibacterial activity against S. aureus. Edible alginate hydrogels enriched with plant extracts hold great nutraceutical potential to be used as natural preservatives for food coating and packaging or as sources of bioactive compounds for biomedical applications.
- Edible flowers of Helichrysum italicum: Composition, nutritive value, and bioactivitiesPublication . Primitivo, Maria João; Neves, Marta; Pires, Cristiana L.; Cruz, Pedro F.; Brito, Catarina; Rodrigues, Ana C.; Carvalho, Carla C. C. R. de; Mortimer, Megan M.; Moreno, Maria João; Brito, Rui M. M.; Taylor, Edward J.; Millson, Stefan H.; Reboredo, Fernando; Campos, Maria; Vaz, Daniela C.; Santos Ribeiro, VâniaHelichrysum italicum (H. italicum) is a halophyte shrub with bright yellow flowers with a strong curry-like aroma. The essential oils of H. italicum have been used in the production of cosmetics and pharmaceuticals, due to their antiallergic and anti-inflammatory properties. In the agri-food sector, H. italicum flowers can be used for seasoning and flavoring food, and as natural food preservatives. Here, we report on the composition, bioactive compounds, and nutritive value of H. italicum flowers. Flowers were mainly composed of carbohydrates (>80 % dry weight), followed by minerals (6.31 ± 0.95 % dw), protein (5.44 ± 0.35 % dw), and lipids (3.59 % ± 0.53 % dw). High percentages of Fe, Zn, Ca, and K were found in the flower material, along with a high content in antioxidants, polyphenols, and carotenoids, as corroborated by the nuclear magnetic resonance (NMR) data. Flowers were mainly composed of saturated fatty acids (SFAs) (54.50 ± 0.95 % of total FA), followed by polyunsaturated fatty acids (PUFAs) (37.73 ± 1.25 % of total FA) and monounsaturated fatty acids (MUFAs) (7.77 ± 0.34 %), as detected by gas chromatography mass spectrometry (GC–MS). The omega-6 PUFA linoleic acid (22.55 ± 0.76 % of total FA) was the most abundant fatty acid found. Flower extracts showed antimicrobial activity against Saccharomyces cerevisiae and Komagataella phaffii, as well as against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) bacteria. H. italicum flower material was nontoxic to human intestinal Caco-2 model cells at concentrations up to 1.0 % w/v.