64 research outputs found

    Fucoidan-degrading fungal strains: screening, morphometric evaluation, and influence of medium composition

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    Ten different fungal strains from the genus Aspergillus, Penicillium, and Mucor were screened for fucoidan hydrolyzing ability aiming to find microorganisms able to produce sulfated fucan-degrading enzymes. Screening was carried out by measuring the strains kinetic and morphometric behavior over plate assays using Laminaria japonica fucoidan as only carbon source, testing three nitrogen sources (urea, peptone, and sodium nitrate). The selected fungal strains were subsequently used in submerged fermentations, which were performed for (1) selection of the strains able to growth over fucoidan medium and (2) media selection, testing the synergy of fucoidan with other sugars for inducing high enzyme titles. Radial expansion and hyphae parameters were observed for Aspergillus niger PSH, Mucor sp. 3P, and Penicillium purpurogenum GH2 grown only over fucoidan-urea medium. A. niger PSH showed the maximum enzymatic activity values, which were significantly different (p<0.05) from those achieved by the other selected fungi. Sucrose addition to fucoidan media proportioned the highest fucoidanase activity values for this fungal strain. This research allowed establishing optimal conditions for metabolites synthesis by fungal stains able to act toward fucoidan ramified matrix.Mexican Science and Technology Council (CONACYT

    The key role of sulfation and branching on fucoidan antitumor activity

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    There is an urgent need for antitumor bioactive agents with minimal or no side effects over normal adjacent cells. Fucoidan is a marine-origin polymer with known antitumor activity. However, there are still some concerns about its application due to the inconsistent experimental results, specifically its toxicity over normal cells and the mechanism behind its action. Herein, three fucoidan extracts (FEs) have been tested over normal and breast cancer cell lines. From cytotoxicity results, only one of the extracts shows selective antitumor behavior (at 0.2 mg mLâ 1), despite similarities in sulfation degree and carbohydrates composition. Although the three FEs present different molecular weights, depolymerization of selected samples discarded Mw as the key factor in the antitumor activity. Significant differences in sulfates position and branching are observed, presenting FE 2 the higher branching degree. Based on all these experimental data, it is believed that these last two properties are the ones that influence the cytotoxic effects of fucoidan extracts.The authors would like to thank the funding from projects 0687_NOVOMAR_1_P, cofunded by INTERREG 2007-2013/POCTEP, CarbPol_u_Algae (EXPL/MAR-BIO/0165/2013), and IF/00376/2014/CP1212/CT0015, funded by the Portuguese Foundation for Science and Technology, FCT, and ComplexiTE (ERC-2012-ADG 20120216-321266), funded by the European Research Council under the European Union's Seventh Framework Programme for Research and Development. The authors would also like to thank FCT, Portugal, for the scholarship of A.S.F. (SFRH/BD/102471/2014), fellowship of C.N. (SFRH/BPD/100627/2014), Investigator grants of A.M. (IF/00376/2014), R.N.-C. (IF/00373/2014), and I.P. (IF/00032/2013) and the financial support to CICECO-Aveiro Institute of Materials (POCI-01-0145-FEDER-007679, FCT UID/CTM/50011/2013) and OOPNA (UID/OUI/00062/2013), through national founds and cofinanced by the FEDER, within the PT2020 Partnership Agreement

    Insights from magnetic resonance imaging of left ventricular non-compaction in adults of North African descent

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    <p>Abstract</p> <p>Background</p> <p>Left ventricular non-compaction (LVNC) is a recently recognized rare disorder. Magnetic resonance imaging (MRI) may help to clarify the uncertainties related to this genetic cardiomyopathy. Despite the fact that many articles have been published concerning the use of MRI in the study of LVNC, there is a lack of data describing the disease in the North African population. The aim of our study is to clarify MRI findings of LVNC in North African patients.</p> <p>Methods</p> <p>In our retrospective cohort, twelve patients (7 male, mean age 53 ± 8 years) underwent MRI for suspected LVNC. Correlations were investigated between the number of non-compacted segments per patient and left ventricular ejection fraction (LVEF), then between the number of non-compacted segments and left ventricular end diastolic diameter. The presence or absence of late gadolinium enhancement (LGE) was qualitatively determined for each left ventricular myocardial segment.</p> <p>Results</p> <p>Non-compaction was more commonly observed at the apex, the anterior and the lateral walls, especially on their apical and mid-cavity segments. 83% of patients had impaired LVEF. There was no correlation between the number of non-compacted segments per patient and LVEF (r = -0.361; p = 0.263), nor between the number of non-compacted segments per patient and left ventricular end diastolic diameter (r = 0.280; p = 0.377). LGE was observed in 22 left ventricular segments. No association was found between the pattern of fibrosis and non-compaction distribution (OR = 2.2, CI [0.91-5.55], p = 0.076).</p> <p>Conclusion</p> <p>The distribution of LVNC in North African patients does not differ from other populations. Ventricular dysfunction is independent from the number of non-compacted segments. Myocardial fibrosis is not limited to non-compacted areas but can extend to compacted segments.</p

    Sulfated seaweed polysaccharides as multifunctional materials in drug delivery applications

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    In the last decades, the discovery of metabolites from marine resources showing biological activity has increased significantly. Among marine resources, seaweed is a valuable source of structurally diverse bioactive compounds. The cell walls of marine algae are rich in sulfated polysaccharides, including carrageenan in red algae, ulvan in green algae and fucoidan in brown algae. Sulfated polysaccharides have been increasingly studied over the years in the pharmaceutical field, given their potential usefulness in applications such as the design of drug delivery systems. The purpose of this review is to discuss potential applications of these polymers in drug delivery systems, with a focus on carrageenan, ulvan and fucoidan. General information regarding structure, extraction process and physicochemical properties is presented, along with a brief reference to reported biological activities. For each material, specific applications under the scope of drug delivery are described, addressing in privileged manner particulate carriers, as well as hydrogels and beads. A final section approaches the application of sulfated polysaccharides in targeted drug delivery, focusing with particular interest the capacity for macrophage targeting

    Current Understanding on Adhesion and Biofilm Development in Actinobacteria

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    Biofilm formation and microbial adhesion are two related and complex phenomena. These phenomena are known to play an important role in microbial life and various functions with positive and negative aspects. Actinobacteria have wide distribution in aquatic and terrestrial ecosystems. This phylum is very large and diverse and contains two important genera Streptomyces and Mycobacteria. The genus Streptomyces is the most biotechnologically important, while the genus Mycobacteria contains the pathogenic species of Mycobacteriaceae. According to the literature, the majority of studies carried out on actinomycetes are focused on the detection of new molecules. Despite the well-known diversity and metabolic activities, less attention has been paid to this phylum. Research on adhesion and biofilm formation is not well developed. In the present review, an attempt has been made to review the literature available on the different aspects on biofilm formation and adhesion of Actinobacteria. We focus especially on the genus Streptomyces. Furthermore, a brief overview about the molecules and structures involved in the adhesion phenomenon in the most relevant genus is summarized. We mention the mechanisms of quorum sensing and quorum quenching because of their direct association with biofilm formation.</jats:p
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