Pattern Recognition in Legume Lectins to Extrapolate Amino Acid Variability to Sugar Specificity. In: Chakrabarti A, Surolia A, editors. Biochemical Roles of Eukaryotic Cell Surface Macromolecules. Cham: Springer International Publishing; 2015. pp. 199-215. [DOI: 10.1007/978-3-319-11280-0_13]

Characterization of anti-soybean agglutinin (SBA) IgY antibodies: a new strategy for neutralization of the detrimental biological activity of SBA

Anti-soybean agglutinin (SBA) IgY was produced, and its potential to neutralize the haemagglutinating activity of SBA in vitro was tested. Thirty-five-week-old hens [treatment (n = 5) and control (n = 5)] were immunized with SBA or injected with saline 4 times every 15 days. Eggs were collected after the last immunization, and IgY was extracted using the polyethylene glycol (PEG) method. Serum anti-SBA IgY titres in immunized hens increased after the first immunization and reached a plateau between days 45 and 60. In contrast, specific IgY titres in the control group remained at basal levels throughout the evaluation. Average IgY titres were significantly higher in the treatment group on days 15, 30, 45, and 60. Total IgY content in the egg yolk extract was 38.7 ± 1.6 and 37.7 ± 1.5 mg/ml for the treatment and control groups, respectively. The specific anti-SBA IgY titer detected in the egg yolk extract was significantly higher (p < 0.001) for hens in the treatment group compared to the control group, with OD450nm values of 0.98 ± 0.05 and 0.058 ± 0.02, respectively. The specificity of anti-SBA IgY was confirmed by the Western blotting, and the inhibition of SBA-induced haemagglutination in vitro was compared with D-galactose, a known molecule that binds to SBA and blocks its binding to erythrocytes. The inhibition of SBA-induced haemagglutination by the anti-SBA IgY reached 512 units of haemagglutination inhibition (UHI), compared to 8 or 256 UHI, respectively, when IgY from control chickens or D-galactose was used. Thus, anti-SBA IgY antibodies were efficiently produced in large quantities and effectively inhibited SBA-induced haemagglutination in vitro.

Detection of Lectin Protein Allergen of Kidney Beans (Phaseolus vulgaris L.) and Desensitization Food Processing Technology

With the increase of food allergy events related to not properly cooked kidney beans (Phaseolus vulgaris L.), more and more researchers are paying attention to the sensitization potential of lectin, one of the major storage and defensive proteins with the specific carbohydrate-binding activity. The immunoglobulin E (IgE), non-IgE, and mixed allergic reactions induced by the lectins were inducted in the current paper, and the detection methods of kidney bean lectin, including the purification strategies, hemagglutination activity, specific polysaccharide or glycoprotein interactions, antibody combinations, mass spectrometry methods, and allergomics strategies, were summarized, while various food processing aspects, such as the physical thermal processing, physical non-thermal processing, chemical modifications, and biological treatments, were reviewed in the potential of sensitization reduction. It might be the first comprehensive review on lectin allergen detection from kidney bean and the desensitization strategy in food processing and will provide a basis for food safety control.

Research advances and prospects of legume lectins

Lectins are widely distributed proteins having ability of binding selectively and reversibly with carbohydrates moieties and glycoconjugates. Although lectins have been reported from different biological sources, the legume lectins are the best-characterized family of plant lectins. Legume lectins are a large family of homologous proteins with considerable similarity in amino acid sequence and their tertiary structures. Despite having strong sequence conservation, these lectins show remarkable variability in carbohydrate specificity and quaternary structures. The ability of legume lectins in recognizing glycans and glycoconjugates on cells and other intracellular structures make them a valuable research tool in glycomic research. Due to variability in binding with glycans, glycoconjugates and multiple biological functions, legume lectins are the subject of intense research for their diverse application in different fields such as glycobiology, biomedical research and crop improvement. The present review specially focuses on structural and functional characteristics of legume lectins along with their potential areas of application.

Legume Lectins: Proteins with Diverse Applications

Lectins are a diverse class of proteins distributed extensively in nature. Among these proteins; legume lectins display a variety of interesting features including antimicrobial; insecticidal and antitumor activities. Because lectins recognize and bind to specific glycoconjugates present on the surface of cells and intracellular structures; they can serve as potential target molecules for developing practical applications in the fields of food; agriculture; health and pharmaceutical research. This review presents the current knowledge of the main structural characteristics of legume lectins and the relationship of structure to the exhibited specificities; provides an overview of their particular antimicrobial; insecticidal and antitumor biological activities and describes possible applications based on the pattern of recognized glyco-targets.

The Distribution of Lectins across the Phylum Nematoda: A Genome-Wide Search

Nematodes are a very diverse phylum that has adapted to nearly every ecosystem. They have developed specialized lifestyles, dividing the phylum into free-living, animal, and plant parasitic species. Their sheer abundance in numbers and presence in nearly every ecosystem make them the most prevalent animals on earth. In this research nematode-specific profiles were designed to retrieve predicted lectin-like domains from the sequence data of nematode genomes and transcriptomes. Lectins are carbohydrate-binding proteins that play numerous roles inside and outside the cell depending on their sugar specificity and associated protein domains. The sugar-binding properties of the retrieved lectin-like proteins were predicted in silico. Although most research has focused on C-type lectin-like, galectin-like, and calreticulin-like proteins in nematodes, we show that the lectin-like repertoire in nematodes is far more diverse. We focused on C-type lectins, which are abundantly present in all investigated nematode species, but seem to be far more abundant in free-living species. Although C-type lectin-like proteins are omnipresent in nematodes, we have shown that only a small part possesses the residues that are thought to be essential for carbohydrate binding. Curiously, hevein, a typical plant lectin domain not reported in animals before, was found in some nematode species.