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  • 1
    Online Resource
    Online Resource
    Design of a New Gemini Lipoaminoacid with Immobilized Lipases Based on an Eco-Friendly Biosynthetic Process
    MDPI AG ; 2021
    In:  Catalysts Vol. 11, No. 2 ( 2021-01-25), p. 164-
    Details
    In: Catalysts, MDPI AG, Vol. 11, No. 2 ( 2021-01-25), p. 164-
    Abstract: Lipoaminoacids (LAA) are an important group of biosurfactants, formed by a polar hydrophilic part (amino acid) and a hydrophobic tail (lipid). The gemini LAA structures allow the formation of a supramolecular complex with bioactive molecules, like DNA, which provides them with good transfection efficiency. Since lipases are naturally involved in lipid and protein metabolism, they are an alternative to the chemical production of LAA, offering an eco-friendly biosynthetic process option. This work aimed to design the production of novel cystine derived gemini through a bioconversion system using immobilized lipases. Three lipases were used: porcine pancreatic lipase (PPL); lipase from Thermomyces lanuginosus (TLL); and lipase from Rizhomucor miehei (RML). PPL was immobilized in sol-gel lenses. L-cystine dihydrochloride and dodecylamine were used as substrates for the bioreaction. The production of LAA was evaluated by thin layer chromatography (TLC), and colorimetric reaction with eosin. The identification and quantification was carried out by High Performance Liquid Chromatographer-Mass Spectrometry (HPLC-MS/MS). The optimization of media design included co-solvent (methanol, dimethylsulfoxide), biphasic (n-hexane and 2-propanol) or solvent-free media, in order to improve the biocatalytic reaction rates and yields. Moreover, a new medium was tested where dodecylamine was melted and added to the cystine and to the biocatalyst, building a system of mainly undissolved substrates, leading to 5 mg/mL of LAA. Most of the volume turned into foam, which indicated the production of the biosurfactant. For the first time, the gemini derived cystine lipoaminoacid was produced, identified, and quantified in both co-solvent and solvent-free media, with the lipases PPL, RML, and TLL.
    Type of Medium: Online Resource
    ISSN: 2073-4344
    URL: Article
    DOI: 10.3390/catal11020164
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662126-5
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  • 2
    Online Resource
    Online Resource
    Influence of PLLA/PCL/HA Scaffold Fiber Orientation on Mechanical Properties and Osteoblast Behavior
    MDPI AG ; 2019
    In:  Materials Vol. 12, No. 23 ( 2019-11-24), p. 3879-
    Details
    In: Materials, MDPI AG, Vol. 12, No. 23 ( 2019-11-24), p. 3879-
    Abstract: Scaffolds based on aligned and non-aligned poly (L-lactic acid) (PLLA)/polycaprolactone (PCL) fibers obtained by electrospinning, associated to electrosprayed hydroxyapatite (HA) for tissue engineering applications were developed and their performance was compared in terms of their morphology and biological and mechanical behaviors. The morphological results assessed by scanning electron microscopy showed a mesh of PLLA/PCL fibers (random and perfectly aligned) associated with aggregates of nanophased HA. Fourier transform infrared spectrometry confirmed the homogeneity in the blends and the presence of nanoHA in the scaffold. As a result of fiber alignment a 15-fold increase in Young’s Modulus and an 8-fold increase in tensile strength were observed when compared to non-aligned fibers. In PLLA/PCL/HA scaffolds, the introduction of nanoHA caused a remarkable improvement of the mechanical strength of this material acting as a reinforcement, enhancing the response of these constructs to tensile stress. In vitro testing was evaluated using osteoblast (MC3T3-E1) cells. The results showed that both fibrous scaffolds were able to support osteoblast cell adhesion and proliferation and that fiber alignment induced increased cellular metabolic activity. In addition, the adhesion and proliferation of Staphylococcus aureus were evaluated and a lower number of colony forming units (CFUs) was obtained in the scaffolds with aligned fibers.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    URL: Article
    DOI: 10.3390/ma12233879
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2487261-1
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  • 3
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    Online Resource
    Attention-Deficit/Hyperactivity Disorder Animal Model Presents Retinal Alterations and Methylphenidate Has a Differential Effect in ADHD versus Control Conditions
    MDPI AG ; 2023
    In:  Antioxidants Vol. 12, No. 4 ( 2023-04-15), p. 937-
    Details
    In: Antioxidants, MDPI AG, Vol. 12, No. 4 ( 2023-04-15), p. 937-
    Abstract: Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent neurodevelopmental disorders. Interestingly, children with ADHD seem to experience more ophthalmologic abnormalities, and the impact of methylphenidate (MPH) use on retinal physiology remains unclear. Thus, we aimed to unravel the retina’s structural, functional, and cellular alterations and the impact of MPH in ADHD versus the control conditions. For that, spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) were used as animal models of ADHD and the controls, respectively. Animals were divided into four experimental groups as follows: WKY vehicle (Veh; tap water), WKY MPH (1.5 mg/kg/day), SHR Veh, SHR MPH. Individual administration was performed by gavage between P28-P55. Retinal physiology and structure were evaluated at P56 followed by tissue collection and analysis. The ADHD animal model presents the retinal structural, functional, and neuronal deficits, as well as the microglial reactivity, astrogliosis, blood-retinal barrier (BRB) hyperpermeability and a pro-inflammatory status. In this model, MPH had a beneficial effect on reducing microgliosis, BRB dysfunction, and inflammatory response, but did not correct the neuronal and functional alterations in the retina. Curiously, in the control animals, MPH showed an opposite effect since it impaired the retinal function, neuronal cells, and BRB integrity, and also promoted both microglia reactivity and upregulation of pro-inflammatory mediators. This study unveils the retinal alterations in ADHD and the opposite effects induced by MPH in the retina of ADHD and the control animal models.
    Type of Medium: Online Resource
    ISSN: 2076-3921
    URL: Article
    DOI: 10.3390/antiox12040937
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704216-9
    SSG: 15,3
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  • 4
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    Online Resource
    Assuring the Biofunctionalization of Silicone Covalently Bonded to Rhamnolipids: Antibiofilm Activity and Biocompatibility
    MDPI AG ; 2022
    In:  Pharmaceutics Vol. 14, No. 9 ( 2022-08-31), p. 1836-
    Details
    In: Pharmaceutics, MDPI AG, Vol. 14, No. 9 ( 2022-08-31), p. 1836-
    Abstract: Silicone-based medical devices composed of polydimethylsiloxane (PDMS) are widely used all over the human body (e.g., urinary stents and catheters, central venous catheters stents) with extreme clinical success. Nevertheless, their abiotic surfaces, being prone to microorganism colonization, are often involved in infection occurrence. Improving PDMS antimicrobial properties by surface functionalization with biosurfactants to prevent related infections has been the goal of different works, but studies that mimic the clinical use of these novel surfaces are missing. This work aims at the biofunctional assessment of PDMS functionalized with rhamnolipids (RLs), using translational tests that more closely mimic the clinical microenvironment. Rhamnolipids were covalently bonded to PDMS, and the obtained surfaces were characterized by contact angle modification assessment, ATR-FTIR analysis and atomic force microscopy imaging. Moreover, a parallel flow chamber was used to assess the Staphylococcus aureus antibiofilm activity of the obtained surfaces under dynamic conditions, and an in vitro characterization with human dermal fibroblast cells in both direct and indirect characterization assays, along with an in vivo subcutaneous implantation assay in the translational rabbit model, was performed. A 1.2 log reduction in S. aureus biofilm was observed after 24 h under flow dynamic conditions. Additionally, functionalized PDMS lessened cell adhesion upon direct contact, while supporting a cytocompatible profile, within an indirect assay. The adequacy of the biological response was further validated upon in vivo subcutaneous tissue implantation. An important step was taken towards biofunctional assessment of RLs-functionalized PDMS, reinforcing their suitability for medical device usage and infection prevention.
    Type of Medium: Online Resource
    ISSN: 1999-4923
    URL: Article
    DOI: 10.3390/pharmaceutics14091836
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2527217-2
    SSG: 15,3
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  • 5
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    Online Resource
    Physicochemical, Nutritional, and Medicinal Properties of Opuntia ficus-indica (L.) Mill. and Its Main Agro-Industrial Use: A Review
    MDPI AG ; 2023
    In:  Plants Vol. 12, No. 7 ( 2023-03-30), p. 1512-
    Details
    In: Plants, MDPI AG, Vol. 12, No. 7 ( 2023-03-30), p. 1512-
    Abstract: The cactus, Opuntia ficus-indica (L.) Mill. (OFI) belongs to the Cactaceae family, which contains about 130 genera and nearly 1600 species. This review aims to evaluate this plant from several perspectives, namely, botanic, physicochemical, nutritional, and medicinal properties, as well as agro-industrial use. The botanical aspects and morphological characteristics of OFI enable genetic variability, ecological adaptation, and broad geographic distribution. Due to its physicochemical and nutritional composition, it has several medicinal properties appropriate (or suitable) for several industries, such as pharmaceutical, food, and cosmetics. Its fruit, the prickly pear (PP), has potential agro-industrial expansion through the application of different conservation and transformation methods, making it possible to obtain a variety of products. The PP is a source of several nutrients and is an effective system to produce varied foods, which have several advantages from a nutritional, sensory, economic, and shelf-life point of view.
    Type of Medium: Online Resource
    ISSN: 2223-7747
    URL: Article
    DOI: 10.3390/plants12071512
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704341-1
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  • 6
    Online Resource
    Online Resource
    Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications
    MDPI AG ; 2022
    In:  Processes Vol. 10, No. 3 ( 2022-03-01), p. 494-
    Details
    In: Processes, MDPI AG, Vol. 10, No. 3 ( 2022-03-01), p. 494-
    Abstract: Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    URL: Article
    DOI: 10.3390/pr10030494
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720994-5
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  • 7
    Online Resource
    Online Resource
    Polyphenols in Health and Disease: Gut Microbiota, Bioaccessibility, and Bioavailability
    MDPI AG ; 2023
    In:  Compounds Vol. 3, No. 1 ( 2023-01-05), p. 40-72
    Details
    In: Compounds, MDPI AG, Vol. 3, No. 1 ( 2023-01-05), p. 40-72
    Abstract: Polyphenolic compounds (PC) are among the most abundant secondary metabolites in nature. They are widely distributed in the world and can be found in fruits, cereals, tea, coffee, and beverages. Due to their structural diversity, polyphenols have many different properties and biological effects. They are resistant to the acid of the gastric tract, and very few are hydrolysed or absorbed in the stomach. Significant portions of ingested polyphenols reach the large intestine and interact with the local bacteria, the so-called gut microbiota. Epidemiological studies confirm that moderate and prolonged intake of foods rich in polyphenols could prevent the development of cancer and chronic diseases, such as cardiovascular, neurodegenerative, type 2 diabetes, and obesity. The current work aims to provide an updated overview on the nature and occurrence of polyphenols, quantification methods, bioaccessibility and bioavailability, and impact on human health, namely through interactions with the gut microbiota.
    Type of Medium: Online Resource
    ISSN: 2673-6918
    URL: Article
    DOI: 10.3390/compounds3010005
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
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  • 8
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    Online Resource
    Erratum: Ribeiro, M. H. L. et al. Lipoaminoacids Enzyme-Based Production and Application as Gene Delivery Vectors. Catalysts 2019, 9, 977
    MDPI AG ; 2020
    In:  Catalysts Vol. 10, No. 2 ( 2020-02-12), p. 223-
    Details
    In: Catalysts, MDPI AG, Vol. 10, No. 2 ( 2020-02-12), p. 223-
    Abstract: The authors wish to make the following erratum to this paper [...]
    Type of Medium: Online Resource
    ISSN: 2073-4344
    URL: Article
    DOI: 10.3390/catal10020223
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662126-5
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  • 9
    Online Resource
    Online Resource
    Design of a Cyclodextrin Bioproduction Process Using Bacillus pseudofirmus and Paenibacillus macerans
    MDPI AG ; 2023
    In:  Future Pharmacology Vol. 3, No. 3 ( 2023-07-11), p. 568-584
    Details
    In: Future Pharmacology, MDPI AG, Vol. 3, No. 3 ( 2023-07-11), p. 568-584
    Abstract: Cyclodextrin (CD) drug delivery systems offer the potential to enhance the desired physicochemical properties and pharmacokinetic parameters of drugs while maintaining their safety. Cyclodextrin-glucosyl-transferase (CGTase) is amongst the most important enzymes used in CD biosynthesis. However, the bioproduction of CDs still faces challenges in terms of optimization and process complexity. This study proposes a novel CD bioproduction system in a batch mode to increase yield and reduce costs. Two bacterial strains were selected: the alkalophilic Bacillus pseudofirmus DSM2517 strain and the neutrophilic Paenibacillus macerans DSM1574 strain. Three different culture media, two temperatures (30 °C and 37 °C), and three scales (shake flasks 20 mL and 100 mL, and bioreactor 3.2 L) were evaluated with respect to bacterial growth kinetics, protein production, and CGTase biosynthesis and activity for β-CD production. Bacterial growth was monitored by measuring optical density (OD600 nm), while CGTase activity was assessed by measuring β-CD production directly in the medium after filtration or in samples after concentration (using a Vivaspin 500® ultrafiltration spin column with a 10 kDa cut-off). β-CD quantification was performed using the phenolphthalein colorimetric method and HPLC. The best conditions for combined growth and protein production, for both microorganisms, in shake flasks were achieved with a medium containing 2% dextrin as the carbohydrate source. Scale-up to the bioreactor displayed improved growth kinetics for both bacteria and higher protein production and CGTase activity for Paenibacillus macerans.
    Type of Medium: Online Resource
    ISSN: 2673-9879
    URL: Article
    DOI: 10.3390/futurepharmacol3030035
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 3136552-8
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  • 10
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    Online Resource
    Predicting SARS-CoV-2 Variant Spread in a Completely Seropositive Population Using Semi-Quantitative Antibody Measurements in Blood Donors
    MDPI AG ; 2022
    In:  Vaccines Vol. 10, No. 9 ( 2022-08-31), p. 1437-
    Details
    In: Vaccines, MDPI AG, Vol. 10, No. 9 ( 2022-08-31), p. 1437-
    Abstract: SARS-CoV-2 serologic surveys estimate the proportion of the population with antibodies against historical variants, which nears 100% in many settings. New approaches are required to fully exploit serosurvey data. Using a SARS-CoV-2 anti-Spike (S) protein chemiluminescent microparticle assay, we attained a semi-quantitative measurement of population IgG titers in serial cross-sectional monthly samples of blood donations across seven Brazilian state capitals (March 2021–November 2021). Using an ecological analysis, we assessed the contributions of prior attack rate and vaccination to antibody titer. We compared anti-S titer across the seven cities during the growth phase of the Delta variant and used this to predict the resulting age-standardized incidence of severe COVID-19 cases. We tested ~780 samples per month, per location. Seroprevalence rose to 〉 95% across all seven capitals by November 2021. Driven by vaccination, mean antibody titer increased 16-fold over the study, with the greatest increases occurring in cities with the highest prior attack rates. Mean anti-S IgG was strongly correlated (adjusted R2 = 0.89) with the number of severe cases caused by Delta. Semi-quantitative anti-S antibody titers are informative about prior exposure and vaccination coverage and may also indicate the potential impact of future SARS-CoV-2 variants.
    Type of Medium: Online Resource
    ISSN: 2076-393X
    URL: Article
    DOI: 10.3390/vaccines10091437
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2703319-3
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