The effect of Cratylia floribunda lectin on renal hemodynamics and ion transport

As lectinas são descritas como (glico)proteínas que se ligam, especificamente e reversivelmente, a carboidratos. Lectinas de leguminosas isoladas da subtribo Diocleinae (Canavalia, Dioclea eCratylia) são estruturalmente homólogas em relação às suas estruturas primárias. Demonstrou-se que as lectinas de DiocleinaeCanavalia brasiliensis, Dioclea guianensis eCanavalia ensiformis alteram diferentemente parâmetros fisiológicos em rins isolados de ratos. Dessa maneira, o objetivo deste estudo foi investigar o papel da lectina de Cratylia floribunda (CFL) na hemodinâmica renal e no transporte de íons em ratos. Em rins isolados perfundidos, CFL (10 mg/mL, n=5) aumentou a pressão de perfusão renal, a resistência vascular renal e reduziu o percentual do transporte tubular de K+, mas não alterou o fluxo urinário, a taxa de filtração glomerular e o percentual de transporte tubular dos íons sódio e cloreto. No leito mesentérico isolado perfundido, CFL (3 e 10 mg/mL/min, n=4) não alterou o tônus basal ou a contração do tecido induzida por fenilefrina (1 mM/mL/min). Em conclusão, a lectina de sementes de Cratylia floribunda altera parâmetros hemodinâmicos renais, provavelmente de origem tubular, e não por alterações hemodinâmicas.Lectins have been described as glycoproteins that reversibly and specifically bind to carbohydrates. Legume lectins isolated from the subtribe Diocleinae (Canavalia, Dioclea andCratylia) are structurally homologous with respect to their primary structures. The Diocleinae lectins of Canavalia brasiliensis, Dioclea guianensis andCanavalia ensiformis have been shown to distinctly alter physiological parameters in isolated rat kidneys. Thus, the aim of this study was to investigate the effect of Cratylia floribunda lectin (CFL) on renal hemodynamics and ion transport in rats. In isolated perfused kidneys, CFL (10 mg/mL, n=5) increased RPP, RVR and decreased %TK+, but did not change urinary flow, glomerular filtration rate, sodium or chloride tubular transport. In isolated perfused mesenteric bed, CFL (3 and 10 mg/mL/min; n=4) did not alter tissue basal tonus or tissue contraction by phenylephrine (1 mM/mL/min). In conclusion, the seed lectin of Cratylia floribunda increased renal hemodynamic parameters showing a kaliuretic effect. This effect could be of tubular origin, rather than a result from haemodynamic alterations

Interactions between indole-3-acetic acid (IAA) with a lectin from Canavalia maritima seeds reveal a new function for lectins in plant physiology

AbstractIndole-3-acetic acid (IAA) bound is considered a storage molecule and is inactive. However, some studies have proposed an additional possible regulatory mechanism based on the ability of lectins to form complexes with IAA. We report the first crystal structure of ConM in complex with IAA at 2.15 Å resolution. Based on a tetrameric model of the complex, we hypothesize how the lectin controls the availability of IAA during the early seedling stages, indicating a possible new physiological role for these proteins. A free indole group is also bound to the protein. The ConM interaction with different forms of IAA is a strategy to render the phytohormone unavailable to the cell. Thus, this new physiological role proposed for legume lectins might be a novel mechanism by which IAA levels are decreased in addition to the destruction and formation of new complexes in the later stages of seed germination

Lectinas como Biomarcadores de Tumores de Cavidade Oral: uma Revisão de Literatura

Introdução: Com o advento de novas pesquisas abordando o processo neoplásico, um grupo peculiar de proteínas tem sido amplamente estudado, as lectinas. Estas proteínas possuem a capacidade de se ligarem de forma reversível a carboidratos com alta especificidade. Devido às alterações no padrão glicoproteico de superfície celular durante o processo neoplásico, as lectinas se tornam uma ferramenta potencial como biomarcadores de células neoplásicas. Objetivo: Investigar a produção científica da aplicação lectinas como biomarcadores de lesões neoplásicas e potencialmente neoplásicas da cavidade oral e analisar quais grupos de lectinas e lesões orais foram mais extensamente estudados, com o objetivo final de traçar o perfil dessas publicações. Método: Realizou-se uma pesquisa de artigos científicos integrando periódicos indexados na base de dados Science Direct, Pubmed e BVS. Os critérios de inclusão estabelecidos foram: Tempo – de 1981 a 2010; Descritores – “lectin” AND “binding” AND “oral” AND “tumor”; Resumo/abstract – língua inglesa. Foi obtido um total de 108 artigos. As publicações foram avaliadas e classificadas em categorias pré-estabelecidas, como número/tipos de lesões e número/tipos de lectinas analisadas. As variáveis estudadas foram correlacionadas e o teste Qui-quadrado foi aplicado. Resultados: Houve notadamente um crescimento de estudos utilizando lectinas como biomarcadores tumorais ao longo dos anos, em que a lesão mais amplamente estudada foi o carcinoma espinocelular e a lectina mais avaliada foi a Arachis hypogea (PNA). Conclusão: Pode-se concluir que a utilização de lectinas como ferramenta de diagnóstico é de crescente importância para a pesquisa em cancerologia devido à sua aplicabilidade, versatilidade e fidedignidade de resultados

ATIVIDADES EDEMATOGÊNICA E ANTINOCICEPTIVA DA LECTINA ISOLADA DA FRAÇÃO ALBUMINA DE Acacia farnesiana

This study aims to evaluate the activity of AFAL in the models of paw edema and chemical nociception. AFAL was injected s.c. or i.v before s.c. injection of carrageenan or dextran in rats to evaluate its pro- or anti-edematogenic effect. The antinociceptive activity was investigated by AFAL i.v. administration in mice in the writhing and formalin tests. Results were expressed as Mean ± SEM and considered significant for p <0.05 (ANOVA). AFAL (0.1 and 1 mg/kg; s.c.) induced paw edema in 30 min, remained constant until the 3rd h, increasing paw volume by 2.9x and 3.4x, respectively, compareci to saline. However, the lectin did not change the edema induced by carrageenan, dextran or formalin. AFAL reduced the number of writhes by 53% (0.1 mg/kg) 60% (1 mg/kg) and 74% (10 mg/kg), but had no effect at any phases of the formalin test. ln conclusion, AFAL presents pro-inflammatory and antinociceptive activity.Este estudo tem como objetivo avaliar a atividade do AFAL nos modelos de edema de pata e nocicepção química. O AFAL foi injetado s.c. ou i.v. antes da injeção s.c. de carragenina ou dextrana em ratos para avaliar seu efeito pró ou antiedematogênico. A atividade antinociceptiva foi investigada pela administração i.v. de AFAL em camundongos nos testes de contorção e formalina. Os resultados foram expressos como Média ± SEM e considerados significativos para p < 0,05 (ANOVA). O AFAL (0,1 e 1 mg/kg; s.c.) induziu edema de pata em 30 min, permaneceu constante até a 3ª h, aumentando o volume da pata em 2,9x e 3,4x, respectivamente, em comparação à solução salina. No entanto, a lectina não alterou o edema induzido por carragenina, dextrana ou formalina. AFAL reduziu o número de contorções em 53% (0,1 mg/kg), 60% (1 mg/kg) e 74% (10 mg/kg), mas não teve efeito em nenhuma fase do teste de formalina. Em conclusão, AFAL apresenta atividade pró-inflamatória e antinociceptiva

Effect of Lectins from Diocleinae Subtribe against Oral Streptococci

Surface colonization is an essential step in biofilm development. The ability of oral pathogens to adhere to tooth surfaces is directly linked with the presence of specific molecules at the bacterial surface that can interact with enamel acquired pellicle ligands. In light of this, the aim of this study was to verify inhibitory and antibiofilm action of lectins from the Diocleinaesubtribe against Streptococcus mutans and Streptococcus oralis. The inhibitory action against planctonic cells was assessed using lectins from Canavaliaensi formis (ConA), Canavalia brasiliensis (ConBr), Canavalia maritima (ConM), Canavalia gladiata (CGL) and Canavalia boliviana (ConBol). ConBol, ConBr and ConM showed inhibitory activity on S. mutans growth. All lectins, except ConA, stimulated significantly the growth of S. oralis. To evaluate the effect on biofilm formation, clarified saliva was added to 96-well, flat-bottomed polystyrene plates, followed by the addition of solutions containing 100 or 200 µg/mL of the selected lectins. ConBol, ConM and ConA inhibited the S. mutans biofilms. No effects were found on S. oralis biofilms. Structure/function analysis were carried out using bioinformatics tools. The aperture and deepness of the CRD (Carbohydrate Recognition Domain) permit us to distinguish the two groups of Canavalia lectins in accordance to their actions against S. mutans and S. oralis. The results found provide a basis for encouraging the use of plant lectins as biotechnological tools in ecological control and prevention of caries disease

Crystallization and preliminary X-ray diffraction analysis of HML, a lectin from the red marine alga Hypnea musciformis

The crystallization and preliminary X-ray diffraction analysis of a red marine alga lectin isolated from H. musciformis is reported

Purification, Partial Characterization and Immobilization of a Mannose-Specific Lectin from Seeds of Dioclea lasiophylla Mart.

Lectin from the seeds of Dioclea lasiophylla (DlyL) was purified in a single step by affinity chromatography on a Sephadex® G-50 column. DlyL strongly agglutinated rabbit erythrocytes and was inhibited by monosaccharides (D-mannose and α-methyl-D-mannoside) and glycoproteins (ovalbumin and fetuin). Similar to other Diocleinae lectins, DlyL has three chains, α, β and γ, with mass of 25,569 ± 2, 12,998 ± 1 and 12,588 ± 1 Da, respectively, and has no disulfide bonds. The hemagglutinating activity of DlyL was optimal in pH 8.0, stable at a temperature of 70 °C and decreased in EDTA solution, indicating that lectin activity is dependent on divalent metals. DlyL exhibited low toxicity on Artemia sp. nauplii, but this effect was dependent on the concentration of lectin in solution. DlyL immobilized on cyanogen bromide-activated Sepharose® 4B bound 0.917 mg of ovalbumin per cycle, showing the ability to become a tool for glycoproteomics studies

Purification, partial characterization and immobilization of a mannose-specific lectin from seeds of Dioclea lasiophylla Mart.

Lectin from the seeds of Dioclea lasiophylla (DlyL) was purified in a single step by affinity chromatography on a Sephadex (R) G-50 column. DlyL strongly agglutinated rabbit erythrocytes and was inhibited by monosaccharides (D-mannose and alpha-methyl-D-mannoside) and glycoproteins (ovalbumin and fetuin). Similar to other Diocleinae lectins, DlyL has three chains, alpha, beta and gamma, with mass of 25,569 +/- 2, 12,998 +/- 1 and 12,588 +/- 1 Da, respectively, and has no disulfide bonds. The hemagglutinating activity of DlyL was optimal in pH 8.0, stable at a temperature of 70 degrees C and decreased in EDTA solution, indicating that lectin activity is dependent on divalent metals. DlyL exhibited low toxicity on Artemia sp. nauplii, but this effect was dependent on the concentration of lectin in solution. DlyL immobilized on cyanogen bromide-activated Sepharose (R) 4B bound 0.917 mg of ovalbumin per cycle, showing the ability to become a tool for glycoproteomics studies

Crystal structure of a pro-inflammatory lectin from the seeds of Dioclea wilsonii Standl

AbstractThe crystal structure and pro-inflammatory property of a lectin from the seeds of Dioclea wilsonii (DwL) were analyzed to gain a better understanding of structure/function relationships of Diocleinae lectins. Following crystallization and structural determination by standard molecular replacement techniques, DwL was found to be a tetramer based on PISA analysis, and composed by two metal-binding sites per monomer and loops which are involved in molecular oligomerization. DwL presents 96% and 99% identity with two other previously described lectins of Dioclea rostrata (DRL) and Dioclea grandiflora (DGL). DwL differs structurally from DVL and DRL with regard to the conformation of the carbohydrate recognition domain and related biological activities. The structural analysis of DwL in comparison to other Diocleinae lectins can be related to the differences in the dose-dependent pro-inflammatory effect elicited in Wistar rats, probably via specific interactions with mast cells complex carbohydrate, resulting in significant paw edema. DwL appears to be involved in positive modulation of mast cell degranulation via recognition of surface carbohydrates. Since this recognition is dependent on site volume and CRD configuration, edematogenesis mediated by resident cells varies in potency and efficacy among different Diocleinae lectins