RESUMO
Lectins are proteins that have the ability to recognize and bind in a reversible and specific way to free carbohydrates or glycoconjugates of cell membranes. For these reasons, they have been extensively used in a wide range of industrial and pharmacological applications. Currently, there is great interest in their production on a large scale. Unfortunately, conventional techniques do not provide the appropriate platform for this purpose and therefore, the heterologous production of lectins in different organisms has become the preferred method in many cases. Such systems have the advantage of providing better yields as well as more homogeneous and better-defined properties for the resultant products. However, an inappropriate choice of the expression system can cause important structural alterations that have repercussions on their biological activity since the specificity may lay in their post-translational processing, which depends largely on the producing organism. The present review aims to examine the most representative studies in the area, exposing the four most frequently used systems (bacteria, yeasts, plants and animal cells), with the intention of providing the necessary information to determine the strategy to follow in each case as well as their respective advantages and disadvantages.
Assuntos
Expressão Gênica , Lectinas/metabolismo , Animais , Carboidratos/química , Lectinas/classificação , Lectinas/isolamento & purificação , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Leveduras/metabolismoRESUMO
Twenty species of marine invertebrates from the Brazilian coast were screened for hemagglutinating/hemolytic activity. In at least twelve tested species, hemagglutinating activity was different for different blood types, suggesting the presence of lectins. Extracts from four species showed hemolytic activity. Two new lectins were purified from the marine sponge Cliona varians (CvL-2) and sea cucumber Holothuria grisea (HGL). CvL-2 was able to agglutinate rabbit erythrocytes and was inhibited by galactosides. The hemagglutinating activity was optimal in pH neutral and temperatures below 70 °C. CvL-2 is a trimeric protein with subunits of 175 kDa. On the other hand, HGL showed both hemagglutinating and hemolytic activity in human and rabbit erythrocytes, but hemolysis could be inhibited by osmotic protection, and agglutination was inhibited by mucin. HGL was stable in pH values ranging from 4 to 10 and temperatures up to 90 °C. In electrophoresis and gel filtration, HGL was a monomeric protein with 15 kDa. CvL-2 and HGL showed different levels of toxicity to Artemia naplii. CvL-2 showed LC50 of 850.1 µg/mL, whereas HGL showed LC50 of 9.5 µg/mL.
Assuntos
Eritrócitos/efeitos dos fármacos , Hemaglutinação/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Lectinas/farmacologia , Poríferos/química , Pepinos-do-Mar/química , Animais , Artemia/efeitos dos fármacos , Brasil , Testes de Hemaglutinação , Humanos , Lectinas/classificação , Lectinas/isolamento & purificação , Poríferos/classificação , Coelhos , Pepinos-do-Mar/classificaçãoRESUMO
Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).
Assuntos
Fungos/metabolismo , Lectinas/metabolismo , Micoses/microbiologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Aspergillus/metabolismo , Candida glabrata/metabolismo , Parede Celular , Cryptococcus neoformans/metabolismo , Histoplasma/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Fatores Imunológicos/isolamento & purificação , Fatores Imunológicos/farmacologia , Lectinas/classificação , Lectinas/isolamento & purificação , Lectinas/farmacologia , Micoses/metabolismo , Receptores Mitogênicos/metabolismoRESUMO
We have probed Tritrichomonas foetus, a protozoan parasite of the urogenital tract of cattle, with gold-labeled and fluorescent lectins, for the localization of glycoconjugates, at the cell surface and in internal cell compartments. The following lectins were used: Con A, PNA, WGA, BSI, BSII, HPA, WFA, SBA, LFA, HPA, and LCA. Carbohydrates were also localized using the Thiéry's technique. Carbohydrate residues were observed in the Golgi and vesicles with all lectins used. However, the labeling pattern varied among the cisternae. A high heterogeneity of cell labeling was detected in the same preparation. The nucleus and the nuclear envelope were labeled with Con A, WGA, BSI, and UEA I, suggesting the presence of D-Man, and/or D-glucose, L-fucose, and GlcNAc. Lysosomes were labeled with Con A and intensely labeled with HPA. The intensity of labeling of the plasma and flagellar membranes varied according to the lectin used.
Assuntos
Glicoconjugados/análise , Tritrichomonas foetus/ultraestrutura , Animais , Bovinos , Células Cultivadas , Corantes Fluorescentes/química , Glicoconjugados/metabolismo , Ouro/metabolismo , Indicadores e Reagentes , Lectinas/análise , Lectinas/classificação , Lectinas/metabolismo , Masculino , Tritrichomonas foetus/citologia , Tritrichomonas foetus/isolamento & purificaçãoRESUMO
Las galectinas se definen por dos propiedades: secuencias de aminoácidos características compartidas y afinidad por azúcares ß-galactosídicos. Numerosas galactinas de mamíferos fueron secuenciadas y bien caracterizadas en diferentes especies, siendo clasificadas como galectina-1 a galectina-10, según sus homologías de secuencia. La identidad entre dominios que ligan carbohidratos de distintas galectinas de una especie de mamífero oscila entre 20-40 por ciento, mientras que la identidad de galectina-1, por ejemplo, entre distintas especies es de 80-90 por ciento. En la presente revisión, se describen las principales propiedades distintivas de las galectinas de mamífero en cuanto a estructura proteica, estructura cristalina, especificidad glicídica y ligandos específicos
Assuntos
Humanos , Camundongos , Ratos , Animais , Bovinos , Técnicas In Vitro , Lectinas/química , Biomarcadores/sangue , Selectinas/química , Sequência de Aminoácidos , Sequência de Carboidratos , Bovinos , Galinhas , Cristalografia , Laminina/química , Laminina/ultraestrutura , Lectinas/classificação , Lectinas/fisiologia , Mamíferos , Dados de Sequência Molecular , Difração de Raios XRESUMO
Las galectinas se definen por dos propiedades: secuencias de aminoácidos características compartidas y afinidad por azúcares ß-galactosídicos. Numerosas galactinas de mamíferos fueron secuenciadas y bien caracterizadas en diferentes especies, siendo clasificadas como galectina-1 a galectina-10, según sus homologías de secuencia. La identidad entre dominios que ligan carbohidratos de distintas galectinas de una especie de mamífero oscila entre 20-40 por ciento, mientras que la identidad de galectina-1, por ejemplo, entre distintas especies es de 80-90 por ciento. En la presente revisión, se describen las principales propiedades distintivas de las galectinas de mamífero en cuanto a estructura proteica, estructura cristalina, especificidad glicídica y ligandos específicos (AU)
Assuntos
Humanos , Camundongos , Ratos , Animais , Bovinos , Técnicas In Vitro , Lectinas/química , Selectinas/química , Biomarcadores/sangue , Mamíferos , Galinhas , Bovinos , Sequência de Aminoácidos , Sequência de Carboidratos , Dados de Sequência Molecular , Difração de Raios X , Lectinas/classificação , Lectinas/fisiologia , Cristalografia , Laminina/química , Laminina/ultraestruturaRESUMO
Se llevó a cabo el análisis de la evaluación sensorial en función al sabor y aceptación general del frijol entero cocido, en cinco variedades de frijol sembrado en seis localidades de México. Se determinó el tiempo de cocción con cocedores tipo Mattson. Se cuantificó el contenido de taninos y la actividad específica de lectinas. Se observaron diferencias estadísticas significativas (p<0.05) en los estudios de evaluación sensorial de los materiales provenientes de Calera específicamente en las variedades que sufrieron heladas y bajas temperaturas. Características como el sabor, color, espesor de caldo e integridad del grano resultaron de interés a los jueces. Se encontraron diferencias significativas (p<0.05) en el tiempo de cocción entre genotipos y entre localidades, observándose un efecto importante en esta determinación causado por las heladas. No se encontró alguna correlación entre el contenido de Ca y Mg en el suelo y el tiempo de cocción de frijol. La concentración de taninos mostró diferencias significativas (p<0.05) para los genotipos y las localidades. La actividad específica de lectinas no mostró ninguna diferencia entre genotipos pero si entre localidades, sin efecto aparente por las bajas temperaturas