Construction and application of a controlled/slow release system based on bioconjugates of calcium carbonate and lectin from dioclea violacea : effect on cervical cancer cells

Lectins are proteins that bind specifically to carbohydrates and are able to form complexes with molecules containing saccharides without changing their structure. Because of the many biological activities displayed by these proteins, they have great applicability in biotechnology. Controlled/slow drug release technology is one of the most promising applications of nanotechnology for disease treatment and diagnosis because it overcomes several problems associated with the use of macromolecules such as proteins as drugs. In this context, the present investigation aimed to develop a system for the controlled release of Dioclea violacea lectin (DVL), a mannose/glucose-specific legume lectin with anticancer properties, by applying two different sizes of CaCO3 particles, a low-cost, broadly available and biocompatible compound. Results show that the systems are feasible and present desirable properties of adsorption and release. The application of the bioconjugates on HeLa cells indicates that the proposed system is effective as a cytotoxic agent against this cell type, even more than the free lectin. The present data demonstrate that the system has a potential application in cancer treatment and the methodology enables the use of other anticancer lectins/proteins.As lectinas são proteínas que se ligam especificamente à carboidratos e são capazes de formar complexos com moléculas contendo sacarídeos sem alterar sua estrutura. Devido às muitas atividades biológicas exibidas por essas proteínas, elas possuem grande aplicabilidade na biotecnologia. A tecnologia de liberação controlada/lenta de medicamentos é uma das aplicações mais promissoras da nanotecnologia no tratamento e diagnóstico de doenças, visto que supera diversos problemas associados ao uso de macromoléculas, como proteínas e medicamentos. Nesse contexto, o presente trabalho teve como objetivo desenvolver um sistema para a liberação controlada da lectina de Dioclea violacea (DVL), uma lectina de leguminosa específica para manose/glicose com propriedades anticâncer, através da aplicação de dois tamanhos diferentes de partículas de CaCO3, um composto de baixo custo, amplamente disponível e biocompatível. Os resultados mostraram que os sistemas são viáveis e apresentam propriedades desejáveis de adsorção e liberação. A aplicação dos bioconjugados nas células HeLa mostrou que o sistema proposto é eficaz como agente citotóxico contra esse tipo de célula, mais potente inclusive que lectina livre. Os dados obtidos demonstram que o sistema tem uma aplicação potencial no tratamento do câncer e a metodologia permite o uso de outras lectinas/proteínas anticâncer

ConBr, the lectin from Canavalia brasiliensis Mart. seeds : forty years of research

Lectins are defined as proteins or glycoproteins capable of specific and reversible binding to carbohydrates. Inside this group of proteins, the most well-studied lectins belong to the Leguminosae family, and inside this family, the Diocleinae subtribe includes the most characterized lectin Concanavalin A (ConA), as well as ConBr, the lectin from Canavalia brasiliensis, the subject of this review. Since 1979, several studies have been published in the literature regarding this lectin, from its isolation and characterization to its several biological activities. This year, 2019, will mark 40 years since researchers have begun to study ConBr and 100 years since the discovery of ConA, making 2019 a momentous year for lectinology. Owing to the abundance of studies involving ConBr, this review will focus on ConBr's purification, physicochemical properties, functional and structural analyses, biological activities and biotechnological applications. This will give researchers a broad glimpse into the potential of this lectin, as well as it characteristics, as we look ahead to its expanding applications in glycomics and biotechnology

A brief review of saliva biomarkers as a diagnostic tool for autism spectrum disorder (asd)

The diagnosis of autistic spectrum disorder (ASD) remains clinical to this date. Immune dysfunction has been a recognized feature in ASD, and several researchers suggest that it can be used as a diagnostic tool by detecting biomarkers as well as an effective route for pharmacological intervention. The molecular biomarkers obtained from biological fluids are gaining relevance because of its lower invasiveness and ease of collection. Patients with autism are characterized by sensory reactivity and behavioral difficulties that can make sample collection problematic and, in this context, saliva appears to be a viable alternative for obtaining relevant biological information, being also especially indicated for children due to its painless and non-invasive sampling characteristics. Also, the saliva represents a valuable resource for studying possible biomarkers of autism. Following is a brief description of the main works published in recent years on saliva biomarkers for the diagnosis of autism

Lectins applied to diagnosis and treatment of prostate cancer and benign hyperplasia : a review

Environmental factors, as well as genetic factors, contribute to the increase in prostate cancer cases (PCa), the second leading cause of cancer death in men. This fact calls for the development of more reliable, quick and lowcost early detection tests to distinguish between malignant and benign cases. Abnormal cell glycosylation pattern is a promising PCa marker for this purpose. Proteins, such as lectins can decode the information contained in the glycosylation patterns. Several studies have reported on applications of plant lectins as diagnostic tools for PCa considering the ability to differentiate it from benign cases. In addition, they can be used to detect, separate and differentiate the glycosylation patterns of cells or proteins present in serum, urine and semen. Herein, we present an overview of these studies, showing the lectins that map glycans differentially expressed in PCa, as well as benign hyperplasia (BPH). We further review their applications in biosensors, histochemical tests, immunoassays, chromatography, arrays and, finally, their therapeutic potential. This is the first study to review vegetable lectins applied specifically to PCa

Differential vasodilator effect of Dioclea rostrata lectin in conductance and resistance arteries : mechanisms and glycoconjugate binding relationships

Lectins are proteins that recognize specific carbohydrates, and the vasorelaxant effect of legume lectins has been previously reported, for example the Dioclea rostrata lectin (DRL). This study evaluated major pathways of DRL-induced relaxation in different artery segments and the possible molecular interactions involved. Rat thoracic aorta, coronary and mesenteric resistance arteries were tested "in vitro" with concentration-response curves to DRL (0.01-100 mu g/mL). L-NAME, indomethacin and high KCl were used to evaluate nitric oxide, cyclooxygenase and hyperpolarization-dependent effects. DRL promoted relaxation of all vessels throughout different mechanisms. L-NAME blunted DRL-induced effects only in the aorta and mesenteric resistance artery. By the use of depolarizing KCl solution, vasodilation was reduced in all arteries, while incubation with indomethacin indicated a role of cyclooxygenase-derived factors for DRL effects in mesenteric and coronary arteries, but not in the aorta. Molecular docking results suggested interactions between DRL and heparan sulphate, CD31 and other glycans present on the membrane surface. These data indicate that the mechanisms involved in DRL-mediated vasodilation vary between conductance and resistance arteries of different origins, and these effects may be related to the capacity of DRL to bind a diversity of glycans, especially heparan sulphate, a proposed mechanoreceptor for nitric oxide synthase and cyclooxygenase activation

Differential vasodilator effect of Dioclea rostrata

Lectins are proteins that recognize specific carbohydrates, and the vasorelaxant effect of legume lectins has been previously reported, for example the Dioclea rostrata lectin (DRL). This study evaluated major pathways of DRL-induced relaxation in different artery segments and the possible molecular interactions involved. Rat thoracic aorta, coronary and mesenteric resistance arteries were tested "in vitro" with concentration-response curves to DRL (0.01-100 mu g/mL). L-NAME, indomethacin and high KCl were used to evaluate nitric oxide, cyclooxygenase and hyperpolarization-dependent effects. DRL promoted relaxation of all vessels throughout different mechanisms. L-NAME blunted DRL-induced effects only in the aorta and mesenteric resistance artery. By the use of depolarizing KCl solution, vasodilation was reduced in all arteries, while incubation with indomethacin indicated a role of cyclooxygenase-derived factors for DRL effects in mesenteric and coronary arteries, but not in the aorta. Molecular docking results suggested interactions between DRL and heparan sulphate, CD31 and other glycans present on the membrane surface. These data indicate that the mechanisms involved in DRL-mediated vasodilation vary between conductance and resistance arteries of different origins, and these effects may be related to the capacity of DRL to bind a diversity of glycans, especially heparan sulphate, a proposed mechanoreceptor for nitric oxide synthase and cyclooxygenase activation

Anti-vatairea guianensis lectin igy antibodies produced in immunized chicken eggs : production, isolation and characterization

Lectins are a group of carbohydrate-binding proteins found in all organisms. Among these proteins, a species that stands out for having several biological activities is Vatairea guianensis lectin (VGL). Techniques involving antibodies can range from classic immunochemistry assays to advanced microscopy techniques. Thus, they can become valuable biotechnological tools since they are able to specifically recognize epitopes of the target molecules. Immunoglobulins are proteins whose main function is to bind with antigens foreign to the individual, in order to neutralize them. In the case of birds, the main class of immunoglobulins Y (IgYs) can be found not only in blood but also in egg yolks. This fact allows for quick and efficient purification of these molecules, facilitating their use as biotechnological tools. This work aimed to produce antibodies against VGL in chickens, implementing a methodology for the production biotechnological tools for the study of lectins. For that purpose, laying hens were immunized with VGL for 15 weeks at 10-day intervals. Collected eggs had the IgY purified and the produced antibody was able to recognize VGL as observed by western blotting. In this sense, the IgYs produced in this work constitute a powerful biotechnological tool available for future studies

Purification and characterization of a highly thermostable GlcNAc-binding lectin from Collaea speciosa seeds

Lectins from plants of the Diocleinae subtribe often exhibit specificity towards mannose/glucose and derived sugars, with some plants also displaying a second lectin specific to lactose/GalNAc. Here, we present a novel lectin from Collaea speciosa, named CsL, that displays specificity for GlcNAc/glucose. The lectin was extracted from Collaea speciosa seeds and purified by a single chromatographic step on a Sephadex G-50 matrix. In solution, the lectin appears as a dimeric protein composed of 25 kDa monomers. The protein is stable at pH 7–8 and dependent on divalent cations. CsL maintained its agglutination activity after heating to 90 °C for 1 h. Glycan array studies revealed that CsL binds to N-glycans with terminal GlcNAc residues, chitobiose and chitotriose moieties. The partial amino acid sequence of the lectin is similar to that of some lactose-specific lectins from the same subtribe. In contrast to other ConA-like lectins, CsL is not toxic to Artemia. Because of its remarkably different properties and specificity, this lectin could be the first member of a new group inside the Diocleinae lectins