Browsing by Author "Caldeira, Jorge"
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- Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiaePublication . Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, Helena Albergaria; Arneborg, NilsThe roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides.
- Challenges in matrix metalloproteinases inhibitionPublication . Laronha, Helena; Carpinteiro, Inês; Portugal, Jaime; Azul, Ana; Polido, Mário; Petrova, Krasimira T.; Salema-Oom, Madalena; Caldeira, JorgeMatrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.
- Challenges in matrix metalloproteinases inhibitionPublication . Laronha, Helena; Carpinteiro, Inês; Portugal, Jaime; Azul, Ana; Polido, Mário; Petrova, Krasimira T.; Salema-Oom, Madalena; Caldeira, JorgeMatrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.
- Effect of saccharomycin, a natural Saccharomyces cerevisiae biocide, on Hanseniaspora guilliermondii cells surfacePublication . Calvário, Joana; Silva, Nelly; Almeida, M. Gabriela; Albergaria, Helena; Eaton, Peter; Macedo, Anjos; Caldeira, Jorge
- HPLC quantitative determination of acrylic monomers released from resins used in dental restorationPublication . Catrau, Mafalda; Marques, Rita; Félix, Sérgio; Caldeira, Jorge; Barahona, Isabel
- Identification of novel GAPDH-derived antimicrobial peptides secreted by Saccharomyces cerevisiae and involved in wine microbial interactionsPublication . Branco, Patrícia; Francisco, Diana; Chambon, Christophe; Hébraud, Michel; Arneborg, Nils; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, HelenaSaccharomyces cerevisiae plays a primordial role in alcoholic fermentation and has a vast worldwide application in the production of fuel-ethanol, food and beverages. The dominance of S. cerevisiae over other microbial species during alcoholic fermentations has been traditionally ascribed to its higher ethanol tolerance. However, recent studies suggested that other phenomena, such as microbial interactions mediated by killer-like toxins, might play an important role. Here we show that S. cerevisiae secretes antimicrobial peptides (AMPs) during alcoholic fermentation that are active against a wide variety of wine-related yeasts (e.g. Dekkera bruxellensis) and bacteria (e.g. Oenococcus oeni). Mass spectrometry analyses revealed that these AMPs correspond to fragments of the S. cerevisiae glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein. The involvement of GAPDH-derived peptides in wine microbial interactions was further sustained by results obtained in mixed cultures performed with S. cerevisiae single mutants deleted in each of the GAPDH codifying genes (TDH1-3) and also with a S. cerevisiae mutant deleted in the YCA1 gene, which codifies the apoptosis-involved enzyme metacaspase. These findings are discussed in the context of wine microbial interactions, biopreservation potential and the role of GAPDH in the defence system of S. cerevisiae.
- Physical and morphological characterization of chitosan/montmorillonite films incorporated with ginger essential oilPublication . Souza, Victor Gomes Lauriano; Pires, João Ricardo Afonso; Rodrigues, Carolina; Rodrigues, Patricia Freitas; Lopes, Andréia; Silva, Rui Jorge; Caldeira, Jorge; Duarte, Maria Paula; Fernandes, Francisco Braz; Coelhoso, Isabel Maria; Fernando, Ana LuisaNovel bionanocomposite films of chitosan/montmorillonite (CS/MMT) activated with ginger essential oil (GEO) were produced and characterized in terms of their physical and morphological properties. The homogenization process led to a good interaction between the chitosan and the nanoparticles, however the exfoliation was diminished when GEO was incorporated. Film glass transition temperature did not statistically change with the incorporation of either MMT or GEO, however the value was slightly reduced, representing a relaxation in the polymer chain which corroborated with the mechanical and barrier properties results. Pristine chitosan films showed excellent barrier properties to oxygen with a permeability of 0.184 × 10−16 mol/m·s·Pa being reduced to half (0.098 × 10−16 mol/m·s·Pa) when MMT was incorporated. Although the incorporation of GEO increased the permeability values to 0.325 × 10−16 mol/m·s·Pa when 2% of GEO was integrated, this increment was smaller with both MMT and GEO (0.285 × 10−16 mol/m·s·Pa). Bionanocomposites also increased the UV light barrier. Thus, the produced bioplastics demonstrated their ability to retard oxidative processes due to their good barrier properties, corroborating previous results that have shown their potential in the preservation of foods with high unsaturated fat content.
- Polymerizable matrix metalloproteinases’ inhibitors with potential application for dental restorationsPublication . Laronha, Helena; Carpinteiro, Inês; Portugal, Jaime; Azul, Ana; Polido, Mário; Petrova, Krasimira T.; Salema-Oom, Madalena; Barahona, Isabel; Caldeira, JorgeCollagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins long term failure. Most MMP inhibitors display significant toxicity and are unsuitable for dental resins’ applications. Here we report a study of a new class of inhibitors that display the unique property of being co-polymerizable with other vinyl compounds present in commercial dental resins, limiting their release and potential toxicity. Computational affinity towards the active site of different MMP-1; -2; -8; -9 and -13 of several compounds showed interesting properties and were synthesized. These free compounds were tested concerning their toxicity upon contact with two different cell types, with no substantial decrease in cell viability at high concentrations. Even so, compound’s safety can be further improved upon copolymerization with commercial dental resins, limiting their release.
- Restorative materials without Bis-GMA – myth or reality?Publication . Garcia, Hermano; Fernandes, Inês Caldeira; Caldeira, Jorge; Pinto, Alexandra; Carpinteiro, Inês; Azul, Ana
- Structure and function of human matrix metalloproteinasesPublication . Laronha, Helena; Caldeira, JorgeThe extracellular matrix (ECM) is a macromolecules network, in which the most abundant molecule is collagen. This protein in triple helical conformation is highly resistant to proteinases degradation, the only enzymes capable of degrading the collagen are matrix metalloproteinases (MMPs). This resistance and maintenance of collagen, and consequently of ECM, is involved in several biological processes and it must be strictly regulated by endogenous inhibitors (TIMPs). The deregulation of MMPs activity leads to development of numerous diseases. This review shows MMPs complexity.