ABSTRACT
The present study evaluated the toxicity of Microgramma vacciniifolia rhizome lectin (MvRL) to Artemia salina, human tumour cell lines (larynx epidermoid carcinoma Hep-2, NCI-H292 lung mucoepidermoid carcinoma, and chronic myelocytic leukaemia K562), and normal peripheral blood mononuclear cells (PBMCs), as well as to Biomphalaria glabrata embryos and adults. MvRL was toxic to A. salina (LC50=159.9 µg/mL), and exerted cytotoxic effects on NCI-H292 cells (IC50=25.23 µg/mL). The lectin (1-100 µg/mL) did not affect the viability of K562 and Hep-2 tumour cells, as well as of PBMCs. MvRL concentration of 1, 10, and 100 µg/mL promoted malformations (mainly exogastrulation) in 7.8%, 22.5%, and 27.7% of embryos, respectively, as well as delayed embryo development in 42.0%, 69.5%, and 54.7% of embryos, respectively. MvRL at a concentration of 100 µg/mL killed B. glabrata embryos (17.7%) and adults (25%). Further, MvRL damaged B. glabrata reproductive processes, which was evidenced by observations that snails exposed to the lectin (100 µg/mL) deposited fewer eggs than those in the control group, and approximately 40% of the deposited eggs exhibited malformations. Comparison of these results with that from A. salina assay indicates that MvRL is adulticidal at the concentration range which is toxic to environment. In conclusion, the cytotoxicity of MvRL on tumour cell and absence of toxicity to normal cell indicate its potential as chemotherapeutic drug. Also, the study revealed that the lectin is able to promote deleterious effects on B. glabrata embryos at environmentally safe concentrations.
Subject(s)
Antineoplastic Agents/pharmacology , Antiparasitic Agents/pharmacology , Artemia/drug effects , Biomphalaria/drug effects , Lectins/pharmacology , Polypodiaceae/chemistry , Rhizome/chemistry , Animals , Antineoplastic Agents/isolation & purification , Antiparasitic Agents/isolation & purification , Cell Line, Tumor , Cell Survival/drug effects , Disease Vectors , Humans , Lectins/isolation & purification , Survival AnalysisABSTRACT
Fusarium oxysporum f. sp. lycopersici races 1, 2, and 3 deteriorate tomato crops since they cause a vascular wilt. Lectins are carbohydrate-binding proteins with hemagglutinating and antifungal activities. This work reports that Microgramma vacciniifolia rhizome lectin (MvRL) inhibits F. oxysporum f. sp. lycopersici race 3 growth (61 %) more intensely than of races 1 (55 %) and 2 (45 %). The hemagglutinating activity of MvRL was inhibited by glycoprotein preparations from mycelia of races 1, 2, and 3, and these data indicate that lectin carbohydrate-binding sites recognized glycosylated molecules from races. Inter-simple sequence repeat (ISSR) marker system showed that race 3 is genetically distinct from races 1 and 2, and thus the highest sensitiveness of F. oxysporum f. sp. lycopersici race 3 to MvRL may be due to molecular characteristics of this race.
Subject(s)
Antifungal Agents/pharmacology , Ferns/chemistry , Fusarium/drug effects , Fusarium/genetics , Plant Lectins/pharmacology , Rhizome/chemistry , Electrophoresis, Polyacrylamide Gel , Fungal Proteins/metabolism , Fusarium/growth & development , Genetic Variation , Microbial Sensitivity TestsABSTRACT
This work reports the isolation of Microgramma vaccinifolia rhizome lectin (MvRL) and the determination of electrochemical potentials of MvRL in the presence of Ca²âº, Mg²âº and human type O erythrocytes. MvRL showed the highest specific hemagglutinating activity with human type O erythrocytes and showed a single polypeptide band of 17 kDa on SDS-PAGE. MvRL hemagglutinating activity was neutralized after dialysis with EDTA, and addition of Ca²âº and Mg²âº restored the activity. Electrochemical potentials of MvRL in the presence of 100 mM Ca²âº (882 mV) and 60 mM Mg²âº (1051 mV) were higher (p<0.05) than in the presence of only 0.15 M NaCl (247 mV), indicating that the electrochemical system was sensitive to structural and physico-chemical changes promoted by these ions. MvRL potential did not change in the presence of type O erythrocytes. The electrochemical system was able to detect changes in electrochemical potentials of MvRL promoted by Ca²âº and Mg²âº, even in a complex environment (human serum supplemented with 40 and 60mM of these ions). The study reveals that the stimulatory effect of Ca²âº and Mg²âº on hemagglutinating activity may be linked to conformational change and/or alterations in surface charge distribution of MvRL.
Subject(s)
Electrochemistry/methods , Lectins/chemistry , Rhizome/chemistry , Calcium , Erythrocytes , Hemagglutination , Humans , Lectins/isolation & purification , Magnesium , Protein ConformationABSTRACT
A novel lectin was isolated from Bothrops leucurus snake venom using a combination of affinity and gel filtration chromatographies. The lectin (BlL) agglutinated glutaraldehyde-treated rabbit and human erythrocytes with preference for rabbit erythrocytes. Galactose, raffinose, lactose, fetal bovine serum and casein inhibited lectin-induced rabbit erythrocyte agglutination. BlL, with a molecular mass of 30 kDa and composed of two subunits of 15 kDa, showed dependence on calcium. BlL is an acidic protein with highest activity over the pH range of 4.0-7.0 and stable under heating to 70°C. Fluorescence emission spectra showed tryptophan residues partially buried within the lectin structure. The percentages of secondary structure revealed by circular dichroism were 1% α-helix, 44% ß-sheet, 24% ß-turn and 31% unordered. BlL showed effective antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis with minimal inhibitory concentrations of 31.25, 62.25 and 125 µg/mL, respectively. In conclusion, B. leucurus snake venom contains a galactoside-binding lectin with antibacterial activity.
