Publications by authors named "Robert F H Dekker"

This work describes the development of a novel biosensor obtained by immobilizing laccase from Pleurotus ostreatus Florida onto a glassy carbon electrode platform modified with zinc oxide quantum dots. For enzyme immobilization, the exopolysaccharide botryosphaeran from Botryosphaeria rhodina MAMB-05 was used. Although both biomaterials are from different fungal sources, laccase immobilization was guaranteed, which was demonstrated by the excellent stability of the fabricated biosensor device for the voltammetric determination of 2,6-dimethoxyphenol (2,6-DMP).

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Microencapsulation has emerged as a promising strategy to enhance the stability and protection of bioactive compounds. In this work, roasted mate tea was microencapsulated using 15 % maltodextrin and lasiodiplodan (0.5-1.

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Article Synopsis
  • The study investigates the antiviral activities of sulfonated polysaccharides, specifically focusing on the exocellular fungal glucan botryosphaeran and its regioselective sulfonation methods: mild sulfonation (MS) and pivaloyl ester (PS).
  • Two derivatives were created with different substitution patterns, showing varying degrees of sulfonation and specificities at C-6 for MS and C-2/C-4 for PS.
  • The MS derivative exhibited strong antiviral effects against Herpes simplex virus type 1 (HSV-1), while PS showed no activity, highlighting that sulfate groups at the C-6 position enhance antiviral properties.
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Background: Lung cancer, a chronic and heterogeneous disease, is the leading cause of cancer-related death on a global scale. Presently, despite a variety of available treatments, their effectiveness is limited, often resulting in considerable toxicity and adverse effects. Additionally, the development of chemoresistance in cancer cells poses a challenge.

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Lung cancer is one of the leading causes of cancer-related deaths in men and women worldwide. Current treatments have limited efficacy, cause significant side effects, and cells can develop drug resistance. New therapeutic strategies are needed to discover alternative anticancer agents with high efficacy and low-toxicity.

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Available treatments for leishmaniasis have been widely used since the 1940s but come at a high cost, variable efficacy, high toxicity, and adverse side-effects. 3,3',5,5'-Tetramethoxy-biphenyl-4,4'-diol (TMBP) was synthesized through laccase-catalysis of 2,6-dimethoxyphenol and displayed antioxidant and anticancer activity, and is considered a potential drug candidate. Thus, this study aimed to evaluate the anti-leishmanial effect of TMBP against promastigote and amastigote forms of Leishmania (L.

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The present study proposes the production of vinegars from pineapple processing residues as an eco-friendly strategy for adding value and economic strengthening of the production chain. Pineapple pulp and peel wines were produced and acetificated to vinegar by wild strains of acetic bacteria using Orlean's method (traditional system) followed by enrichment with leaf extract of Red-Jambo, Syzygium malaccense. Appreciable phenolic contents and antioxidant potential were found in pulp and peel vinegars with the added leaf extract.

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Herpes simplex virus type 1 (HSV-1) is a persistent human pathogen, and the emergence of strains resistant to Acyclovir (ACV, reference drug) shows the urgency to develop new treatments. We report the antiherpetic mechanism of the action of lasiodiplodan (LAS-N, (1 → 6)-β-d-glucan) and its sulfonated derivative (LAS-S3) in vitro and in vivo. LAS-S3 showed anti-HSV-1 action with high selectivity indices for HSV-1 KOS (88.

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Obesity is associated with other diseases such as diabetes and cancer. Botryosphaeran, a fungal (1→3)(1→6)-β-d-glucan, is described to present antimutagenic, hypoglycemic, hypocholesterolemic, and antitumor activities when administered by gavage over 15 days in rats and mice. Thus, the present study aims to analyze the metabolic effects of Botryosphaeran (12 mg/kg body weight/day) treatment over 30 days in obese Wistar male rats.

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Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)-β-d-glucan (botryosphaeran) have been described in the literature, but its effects on inflammation have not been evaluated. This study aimed to investigate the action of botryosphaeran on experimental mice models of carrageenan-induced acute pleurisy and acute paw edema, and complete Freund's adjuvant-induced persistent paw edema. All botryosphaeran doses tested (1.

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Breast cancer is the most common cancer worldwide among the female population. The fungal exopolysaccharide botryosphaeran is a (1→3)(1→6)-β-D-glucan with limited solubility in water that can be promoted through carboxymethylation. Thus, the aim of this study was to examine anticancer effects of carboxymethylated-botryosphaeran (CM-BOT) on breast cancer MCF-7 cells cultivated in multicellular tumor spheroids (MCTS).

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Article Synopsis
  • - Botryosphaeran, a specific type of β-d-glucan, shows beneficial properties like reducing tumor growth, managing blood sugar levels, and fighting oxidative stress and inflammation.
  • - In a study, different groups of rats (both non-obese and obese) were inoculated with tumor cells and treated with botryosphaeran to observe its effects on various biological markers after 15 days.
  • - Results indicated that botryosphaeran reduced oxidative stress and inflammation in obese rats and improved antioxidant levels and metabolic health, showcasing its potential as a treatment for tumors.
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The oxidation process of 2,6-dimethoxyphenol (2,6-DMP) by laccase from Botryosphaeria rhodina MAMB-05 and the corresponding enzyme-mediator systems was studied using cyclic voltammetry (CV). The enzyme was classified as a high oxidation potential laccase (> 0.70) V vs.

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Leishmaniasis is an infectious-parasitic disease caused by the protozoan Leishmania spp. The available treatments are based upon expensive drugs bearing adverse side-effects. The search for new therapeutic alternatives that present a more effective action without causing adverse effects to the patient is therefore important.

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The infection of mammalian cells by enveloped viruses is triggered by the interaction of viral envelope glycoproteins with the glycosaminoglycan, heparan sulfate. By mimicking this carbohydrate, some anionic polysaccharides can block this interaction and inhibit viral entry and infection. As heparan sulfate carries both carboxyl and sulfate groups, this work focused on the derivatization of a (1→3)(1→6)-β-D-glucan, botryosphaeran, with these negatively-charged groups in an attempt to improve its antiviral activity.

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Flour from Pereskia aculeata leaf and green banana were used as ingredients in the formulation of a cereal bar with added Lactobacillus acidophilus LA02-ID-1688. Encapsulation in a calcium-alginate hydrogel reinforced with magnesium hydroxide was used as a strategy to protect the probiotic cells under gastrointestinal conditions and to prolong shelf-life. The results are relevant especially for maintaining cell viability during shelf-life; a challenge for the food industry in relation to dry probiotic products.

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Two biomass types of Botryosphaeria rhodina MAMB-05 (VMSM and M3) were evaluated to determine their effectiveness in removing Ag(I) ions from synthetic solutions. Both biomass types obtained good results in the biosorption process with maximum biosorption capacities (q) for the Langmuir model of 34.67 and 39.

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Lignin is an abundant natural plant aromatic biopolymer containing various functional groups that can be exploited for activating lignin for potential commercial applications. Applications are hindered due to the presence of a high content of methyl/methoxyl groups that affects reactiveness. Various chemical and enzymatic approaches have been investigated to increase the functionality in transforming lignin.

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A hydrogel containing exocellular (1 → 6)-β-D-glucan (lasiodiplodan, LAS) was developed and its wound healing potential was evaluated. β-Glucans have attracted much interest by the cosmetic industry sector because of their bioactive and functional properties and in promoting skin health. In the present work an β-glucan was studied as a healing biomaterial that has not hitherto been reported in the scientific literature.

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Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Factors increasing the risks for CVD development are related to obesity, diabetes, high blood cholesterol, high blood pressure and lifestyle. CVD risk factors may be treated with appropriate drugs, but prolonged can use cause undesirable side-effects.

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A photoelectrochemical biosensing strategy for the highly sensitive detection of the flavonoid rutin was developed by synergizing the photoelectrocatalytic properties of hematite (α-FeO) decorated with palladium nanoparticles (PdNPs) and the biocatalysis towards laccase-based reactions. The integration of α-FeO.PdNPs with a polyphenol oxidase as a biorecognition element yields a novel biosensing platform.

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Surface-enhanced Raman spectroscopy (SERS) became a useful analytical technique with the development of appropriate metallic substrates. The need for SERS substrates that immobilize metallic nanoparticles prompted this work to search for an appropriate material. This work presents the preparation, characterization and application of a SERS substrate for crystal violet (CV) detection, as the probe molecule.

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Obesity is an important risk factor in tumor development. Botryosphaeran, a (1 → 3)(1 → 6)-β-D-glucan, produced by the fungus Botryosphaeria rhodina (MAMB-05), is a high molecular mass, water-soluble exopolysaccharide. It consists of a main chain of (1 → 3)-linked β-d-glucose units, with a degree of branching of ~22% at carbon-6 with glucose and gentiobiose residues linked through β-(1 → 6)-bonds, and presents a triple helix conformation.

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Studies demonstrate that obesity can increase tumor development. Botryosphaeran, a fungal (1→3)(1→6)-β-D-glucan, presents antimutagenic, antiproliferative and pro-apoptotic activities. This study evaluated the effects of botryosphaeran on tumor development and metabolic and hematological parameters in tumor-bearing obese and non-obese rats.

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Laccase from Botryosphaeria rhodina MAMB-05 was covalently immobilized on carboxymethyl-botryosphaeran by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC/NHS) in aqueous solution. This approach was employed to fabricate a novel laccase-based biosensor to electrochemically quantify quercetin (QCT), using a simple carbon black paste electrode as a transducer. The proposed biosensor was characterized by electrochemical impedance spectroscopy and Nyquist plots were used to evaluate the immobilization of the enzyme.

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