Lectins as plant defense proteins

Chitin-binding protein behavior at chitosan interface studied by quartz crystal microbalance with dissipation monitoring (QCM-D): Binding quantification, orientation and affinity constants

A full comprehension of chitosan interaction with proteins is yet to be achieved, in view of the complexity of the physico-chemical behaviors found in the chitosan family, and the diversity of possible protein interaction mechanisms. In this work, we studied the interactions between chitosans and wheat germ agglutinin (WGA), a lectin that can bind chitin thanks to an amino-acid pattern called the hevein-like chitin-binding domain (CBD). The specificity of CBD interactions with chitin/chitosan chains and the impact of the degree of acetylation (DA) of chitosan have been studied by quartz crystal microbalance with dissipation monitoring (QCM-D). The mass per unit area of WGA adsorbed on chitosan was six times higher than that of immunoglobulin G (IGG), which does not contain a CBD. The mass per unit area of deposited WGA was also almost twice as high at higher chitosan DAs (54 %, 67 %, 76 %) than at lower DAs (0.5 %, 15 %, 35 %), evidencing more specific interaction with "chitin-like" chitosans. WGA is a dimer at neutral pH and presents 4 CBDs on each monomer. The repartition of these CBDs seems to allow for reorganization of WGA on the chitosan surface in order to favor the interactions of this chitosan with a higher number of proteins. Furthermore, the binding kinetics have been assessed and modelled with a two-step association model, providing insights on the observed association constants. These results indicate that QCM-D constitutes a suitable method for the analysis of lectin CBD-chitosan dynamic interactions and could be applied to other types of proteins, in particular CBD proteins or further used in biosensor elaboration or biomaterial coating assessment with chitosan of different DAs.

Mutation of a gene with PWWP domain confers salt tolerance in rice

Salinity is a major problem due to the continuous increase in the salinization of agricultural lands, particularly, paddy fields. Using a forward genetics approach, salt-insensitive TILLING line 3, sitl3, was selected from a core population induced by gamma-ray irradiation. Under salt stress, sitl3 had greater fresh weight and chlorophyll content, and lower H2O2 and Na+ contents than the wild-type. In the gene (LOC_Os07g46180) with two PWWP domains (named Oyza sativa PWWP4, OsPWWP4) of sitl3, a premature stop was caused by an SNP, and was named OsPWWP4p.Gly462* (a stop gain occurred from the 462th amino acid residue). The OsPWWP4 and substrate proteins (OsEULS2, OsEULS3, and OsEULD2) were identified using yeast two-hybrid, bimolecular fluorescence complementation, in vitro pull-down, and in vitro methyltransferase assays. Subcellular localization of OsPWWP4 and OsPWWP4p.Gly462*GFP-tagged proteins revealed they were both localized in the nucleus, while OsEULS2, OsEULS3, and OsEULD2 GFP-tagged proteins were found in the nucleus and cytosol of rice protoplasts. The expression levels of OsEULS2, OsEULS3, OsEULD2 under salt stress were higher in sitl3 than in wild-type plants. In contrast, OsPWWP4 expression was higher in the latter. Genes involved in the salt overly sensitive (SOS) pathway showed higher expression in the aerial tissues of silt3 than in the wild-type. CRISPR/Cas9-mediated OsPWWP4 knock-out transgenic plants showed salt tolerance phenotypes with low Na+ contents and low Na+/K+ ratios. The data suggest that sitl3 is a valuable genetic resource for understanding protein post-translational regulation-related salinity tolerance mechanisms such as methyltransferase activities, and for improving salt tolerance in rice through breeding.

Novel LacdiNAc-specific lectin from Dioclea reflexa seeds exhibits inflammatory and hypernociceptive properties

Diocleinae lectins are well known for their prevalent affinity for glycomannosides. However, a rare subset displays specificity towards galactosides. This study describes the characterization of DrfL II, a novel lectin from Dioclea relexa seeds with specificity for N,N'-diacetyl-lactosamine (LacdiNAc). Isolated by lactose-affinity chromatography, DrfL II exists as a homotetramer formed by associations of a 29 kDa chainis a tetrameric lectin composed of identical 29 kDa subunits and strongly agglutinates rabbit erythrocytes, an activity inhibited by α-lactose. DrfL II binds preferentially to LacdiNAc (GalNAcβ1-4GlcNAc) over N-acetyl-lactosamine (LacNAc, Galβ1-4GlcNAc), functioning optimally between pH 6-8 and retaining stability up to 60 °C. Partial protein sequencing revealed homology with other legume lectins. Beyond its distinct carbohydrate specificity, DrfL II induced significant inflammatory and hypernociceptive responses in mice, as shown by paw edema and von Frey assays, while remaining non-toxic to Artemia nauplii. This finding expand our understanding of the galactoside-specific lectins within the Diocleinae subtribe, suggesting potential roles in physiological processes yet to be fully elucidated and potential biological application within the inflammation field.

Novel Lectins from Bauhinia with Differential N-Glycan Binding Profiles

The specific interaction of lectins with carbohydrates and glycoconjugates grants these proteins a distinct ability to decode the glycocode. Essential for various biological processes in all organisms, this carbohydrate-binding activity also establishes lectins as valuable tools in fields such as glycomics, medicine, and biotechnology. Considering that the discovery of novel lectins with unique binding profiles is particularly relevant, this study investigated the binding specificity of two lectins extracted from Bauhinia seeds toward simple sugars, N-glycans and O-glycans. The combination of agglutination-inhibition assays and glycan arrays revealed subtle differences in the binding of the lectins to galactosides and glycans containing specific motifs, such as LewisX, LacdiNAc, and fucosylated LacdiNAc. Despite slight differences in carbohydrate-binding patterns, both lectins showed similar results in toxicity assays using Artemia salina nauplii and cytotoxicity assays on cancer cell lines, with neither lectin exhibiting significant toxicity. Additionally, both lectins demonstrated low cytotoxicity toward HeLa (cervical adenocarcinoma), HT1080 (fibrosarcoma), and NHDF (normal fibroblasts), even at concentrations up to 125 μg/mL. Analysis of the partial amino acid sequences of these lectins revealed conserved residues compared to other lectins of the genus, as well as secondary structure conformations similar to those of other legume lectins. This research represents a significant advancement in the understanding of lectins from the genus Bauhinia, and future structural studies could further elucidate the interactions of these proteins with their ligands, providing fundamental insights into their biological functions and paving the way toward potential applications.

Chitosan surface interaction platform for protein binding quantification by fluorescence microscopy, application to the specificity of CBD proteins

Surface-proteins interactions play key roles in many domains such as biomedicine, nanotechnology and the biology of plant-insect interactions. This article proposes a platform that allows to quantify surface interaction of proteins with chitin and chitosans to further discriminate and study specific interactions of proteins with chitin-binding domains (CBD). The platform consists in covalently grafted chitosan thin films of various degrees of acetylation (DA) through surface silanisation, spin-coating and water-temperature treatment. The obtained films were thoroughly characterized by infrared spectroscopy, contact angle measurements, atomic force microscopy and wide and small-angle X-ray scattering. Protein affinity to coated surfaces of reacetylated chitosans with degrees of acetylation ranging from 0.5 % to 76 % was evaluated by fluorescence microscopy. The specific affinity of lectins with a CBD was evidenced in comparison to proteins without CBD. As expected, the affinity was stronger at higher DAs, suggesting that the acetylation pattern play a part in specific lectin binding. In conclusion, chitosan films were fully characterized, and the elaborated platform shows promising results in screening protein interactions to chitin. This protein interaction platform is reportedly the first method able to differentiate the interactions of proteins containing a CBD and proteins which do not contain one, with whole chain "chitin-like" chitosans, by means of a simple and direct fluorescent microscopy quantification. This platform could further be used for other types of chitin-binding proteins or applied to other polysaccharide-protein interactions.

Regulation of PD-L1 glycosylation and advances in cancer immunotherapy

Protein glycosylation plays a versatile role in regulating homeostasis, such as cell migration, protein sorting, and the immune response. Drugs aimed at targeting glycosylation have strong implications for immunity enhancement, diagnosis, and cancer regression. Programmed death-ligand 1 (PD-L1), expressed in cancer or antigen-presenting cells, binds to programmed cell death protein 1 (PD-1) and suppresses T cells. Glycosylation of PD-L1 at N35, N192, N200, and N219 stabilizes PD-L1 on the cancer cell surface, which contributes to immune evasion by inhibiting T cell activity. To date, at least six glycosyltransferases and four associate proteins are known to regulate PD-L1 glycosylation. Terminal modifications such as poly-N-acetyl-lactosamine (poly-LacNAC), sulfation, and sialylation are commonly found on PD-L1, acting as an immune recognition ligand and regulating certain immune responses. Studies have identified many mechanisms and potential therapeutic targets within the glycosylation pathways of PD-L1, revealing their involvement in cancer pathology, immune evasion, and resistance to immunotherapy. In this review, we covered the glycoforms, terminal moiety, binding lectin, glycosyltransferase, as well as sugar analogs focusing on glycosylated PD-L1. We present a mechanism that originates from the endoplasmic reticulum (ER)-Golgi apparatus (Golgi) and its subsequent translocation to the cell membrane. This pathway determines the immune suppression function of PD-L1 and therefore regulates the immune response such as T cells, monocytes, and macrophages. This collection of findings underscores the significance of glycosylation in the role of PD-L1 in cancer and highlights multiple potential targets and strategies for improving therapeutic intervention and diagnostic techniques.

Effects of Heat Treatment on Physicochemical Properties of Moringa oleifera Lam. Leaf Protein

M. oleifera leaves represent a novel and nutritious food. Prior research has demonstrated that M. oleifera leaves can elicit allergic responses in BALB/c mice. Based on these findings, further studies were conducted to investigate the effects of heat treatment on the allergenicity, particle size, zeta potential, total sulfhydryl (TSH) content, hydrophilicity and hydrophobicity, ultraviolet spectrum, and intrinsic fluorescence spectrum of M. oleifera leaf protein. Additionally, in vitro digestion experiments were carried out to gain further insights into the protein's behavior under these conditions. The experiment simulated the alterations in M. oleifera leaf protein during the processes of cooking and digestion. The findings of this experiment can provide certain guidance for the processing of M. oleifera leaf products. The hydrophilicity, hydrophobicity, transmembrane region, antigen index, calcium binding site, spatial structure, and homology of M. oleifera leaf fructose 1,6 bisphosphate aldolase (FBA) were simulated and calculated based on the amino acid sequence of the 36 kDa allergen. These parameters collectively serve to indicate the allergenic activity of the peptide. The findings of the analysis align with the outcomes of the sensitization experiments, suggesting that the FBA of M. oleifera leaves is indeed consistent. In conjunction with the heat treatment experiments, this research can inform the preparation of M. oleifera leaf foods and provide a foundation for further investigation into M. oleifera leaf allergens.

The future of plant lectinology: Advanced technologies and computational tools

Lectins play crucial roles in many biological processes and serve as tools in fields ranging from agriculture to biomedicine. While classical methods for lectin discovery and characterization were foundational for the field, they often lack sensitivity and throughput, limiting the detection of less abundant or weakly binding lectins, such as the stress-inducible or monovalent lectins. This review focuses on recent advancements in plant lectin research, particularly novel technologies that complement traditional approaches. Techniques such as glycan microarrays allow rapid assessment of lectin specificity across a diverse range of glycans by evaluating interactions with immobilized glycans on solid surfaces. Phage display libraries enable the identification of carbohydrate-mimetic peptides and the development of ligands for lectins by presenting diverse peptide libraries on bacteriophages. Genomic and transcriptomic analyses facilitate the exploration of the lectome in various plant species by scanning entire datasets to identify genes that contain lectin motifs-specific conserved amino acid sequences involved in carbohydrate recognition-and lectin domains, the larger structural regions that facilitate and stabilize these interactions. Additionally, computational methods-including molecular docking, molecular dynamics simulations, and machine learning pipelines-support predictions of lectin structures and binding properties, underpinning experimental efforts. These advanced techniques bring increased efficiency, accuracy, and a broader scope to lectin studies, with potential impacts across multiple fields. However, challenges such as data complexity and the need for experimental validation for computational methods remain. The future of lectin research will depend on the integration of these methods and the strengthening of interdisciplinarity to unlock the full potential of lectins.

Lectin-carbohydrate analysis by molecular dynamics: Parkia lectins case study

Understanding lectin-carbohydrate interactions at the structural and molecular levels is crucial to the field of lectins, as the diverse roles and biological activities exhibited by these proteins are fundamentally linked to their specific binding to target glycoconjugates. This study aimed to apply molecular dynamics to analyze the structure and binding properties of Parkia lectins. 3D structures of Parkia platycephala and P. biglobosa lectins, both unliganded and in complex with D-mannose, were used as inputs for simulations. The trajectories data enabled the study of stability, carbohydrate-binding interactions, and intermonomeric contacts for both proteins. The results revealed stable binding of D-mannose within the lectin domains and their binding mode at each of the three domains, displaying consistent binding motifs across the sites, with slight variations between the lectins and other Jacalin-related lectins. Despite these variations, the binding energies of the lectins with the ligand, as estimated using MM/GBSA, demonstrated favorable interactions in all cases. The dimeric interfaces of both lectins could be identified, and the main contacts have been mapped. These findings enhance our understanding of lectin-carbohydrate interactions and provide insights into the structural properties of Parkia lectins for potential biological and therapeutic applications.

The crystal structure of Nictaba reveals its carbohydrate-binding properties and a new lectin dimerization mode

Nictaba is a (GlcNAc)n-binding, stress-inducible lectin from Nicotiana tabacum that serves as a representative for the Nictaba-related lectins, a group of proteins that play pivotal roles in plant defense mechanisms and stress response pathways. Despite extensive research into biological activities and physiological role(s) of the lectin, the three-dimensional structure of Nictaba remained largely unknown. Here, we report crystal structures for Nictaba in the apo form and bound to chitotriose. The structures reveal that the Nictaba protomer has a jelly-roll fold, similar to the cucumber lectin Cus17, but exhibit a unique and previously unseen mode of dimerization. The chitotriose binding mode, similar to Cus17, centers around the central GlcNAc residue, providing insights into the determinants of specificity of Nictaba towards carbohydrate structures. By integrating these structural insights with inputs from glycan arrays, molecular docking, and molecular dynamics simulations, we propose that Nictaba employs a single carbohydrate-recognition domain within each of the two subunits in the dimer to display pronounced specificity towards GlcNAc-containing carbohydrates. Furthermore, we identified amino acid residues involved in the extended binding site capable of accommodating structurally diverse high-mannose and complex N-glycans. Glycan array and in silico analyses revealed interactions centered around the conserved Man3GlcNAc2 core, explaining the broad recognition of N-glycan structures. Collectively, the structural and biochemical insights presented here fill a void into the atlas of lectin structure-function relationships and pave the way for future developments in plant stress biology and lectin-based applications.

Isolation, purification, and characterization of lectins from medicinal plant Combretum glutinosum seeds endowed with analgesic and antiulcer properties

In the pursuit of safer and more effective treatments, there is a growing interest in plant-derived compounds, particularly lectins, because of their diverse pharmacological properties. This study focused on isolating, purifying, and characterizing lectin from Combretum glutinosum seeds (CGSLs) to assess its potential as an analgesic and antiulcer agent. CGSL extraction involved defatting and buffer extraction, followed by purification using ammonium sulfate fractionation and fetuin-agarose affinity column chromatography. The isolectins (iso-CGSLs), each consisting of 60 kDa and 57 kDa heterodimeric subunits, displayed glycoprotein properties with a 40 % neutral sugar content. They exhibited peak activity at 55 °C and remained stable for up to the fifth day at room temperature. The activity exhibited a pH dependence, peaking between 7.5 and 10.5, and all seemingly operated independently of metal ions. CGSL, at optimal doses ranging from 6 to 12 mg/kg, had significant analgesic effects on acetic acid-induced writhing and hot plate tests in mice. Evaluation using 0.7 % acetic acid resulted in notable pain reduction across all doses (P < 0.05). The analgesic effect of lectin was partially reversed by naloxone (a morphine antagonist), indicating partial involvement of the opioid receptor system. Furthermore, CGSL exhibited antiulcer effects in ethanol-induced gastric ulcer models in rats, highlighting its therapeutic potential as a natural alternative for analgesic and antiulcer treatments.

Molecular Identification and Characterization of Hevein Antimicrobial Peptide Genes in Two-Row and Six-Row Cultivars of Barley (Hordeum vulgare L.)

Heveins are one of the most important groups of plant antimicrobial peptides. So far, various roles in plant growth and development and in response to biotic and abiotic stresses have reported for heveins. The present study aimed to identify and characterize the hevein genes in two-row and six-row cultivars of barley. In total, thirteen hevein genes were identified in the genome of two-row and six-row cultivars of barley. The identified heveins were identical in two-row and six-row cultivars of barley and showed a high similarity with heveins from other plant species. The hevein coding sequences produced open reading frames (ORFs) ranged from 342 to 1002 bp. Most of the identified hevein genes were intronless, and the others had only one intron. The hevein ORFs produced proteins ranged from 113 to 333 amino acids. Search for conserved functional domains showed CBD and LYZ domains in barley heveins. All barley heveins comprised extracellular signal peptides ranged from 19 to 35 amino acids. The phylogenetic analysis divided barley heveins into two groups. The promoter analysis showed regulatory elements with different frequencies between two-row and six-row cultivars. These cis-acting elements included elements related to growth and development, hormone response, and environmental stresses. The expression analysis showed high expression level of heveins in root and reproductive organs of both two-row and six-row cultivars. The expression analysis also showed that barley heveins is induced by both biotic and abiotic stresses. The results of antimicrobial activity prediction showed the highest antimicrobial activity in CBD domain of barley heveins. The findings of the current study can improve our knowledge about the role of hevein genes in plant and can be used for future studies.

Exploring the dual role of anti-nutritional factors in soybeans: a comprehensive analysis of health risks and benefits

Soybeans (Glycine max [L.] Merr.) are a globally significant crop, valued for their high protein content and nutritional versatility. However, they contain anti-nutritional factors (ANFs) that can interfere with nutrient absorption and pose health risks. This comprehensive review examines the presence and impact of key ANFs in soybeans, such as trypsin inhibitors, lectins, oxalates, phytates, tannins, and soybean polysaccharides, based on recent literature. The physiological roles, potential health hazards of the ANFs, and the detailed balance between their harmful and beneficial effects on human health, as well as the efficacy of deactivation or removal techniques in food processing, were discussed. The findings highlight the dual nature of ANFs in soybeans. Some ANFs have been found to offer health benefits include acting as antioxidants, potentially reducing the risk of cancer, and exhibiting anti-inflammatory effects. However, it is important to note that the same ANFs can also have negative impacts. For instance, trypsin inhibitors, lectins, and tannins may lead to gastrointestinal discomfort and contribute to mineral deficiencies when consumed in excess or without proper processing. This review will provide a clear understanding of the role of ANFs in soybean-based diets and to inform future research and food processing strategies.

Antimicrobial Functions of Galectins from Fish, Mollusks, and Crustaceans: A Review

Galectins are a member of the β-galactoside binding protein family, which play a pivotal role in the immune defense of vertebrates as a pattern recognition receptor and occupy an important position in the innate immune system of invertebrates. The study of galectins in aquatic organisms has only recently emerged. Galectins in aquatic animals exhibit agglutination activity toward bacteria, inhibit bacterial growth, and enhance phagocytosis of immune cells. Additionally, some galectins contribute to the antiviral immune defenses of aquatic animals. This review aims to review recent advancements in the antimicrobial mechanisms, molecular structures, and evolution of galectins from fish, mollusks, and crustaceans. The antimicrobial galectins, as crucial components in the innate immune defense, pave new avenues for developing innovative disease control strategies in aquaculture.

Isolation, characterization and antimicrobial properties of hepatopancreas lectin of the freshwater crab Oziotelphusanaga

Lectins are versatile proteins that specifically recognize and interact with sugar moieties expressed on the cell surface. The potential of lectin in drug targeting and delivery has instigated interest to identify natural lectins. Crabs have been identified as a rich source of lectin because the innate immune system is activated on encounter of pathogens and helps in the production of lectin. Although the presence of lectins in crab's hemolymph is well documented, little information about lectin in hepatopancreas, a vital organ for immunity and digestion in crustaceans, is currently available. A calcium dependent lectin (75 kDa) was purified from the hepatopancreas of the freshwater crab Oziotelphusa naga by bioadsorption and fetuin linked Sepharose 4B affinity chromatography technique. The isolated hepatopancreas lectin is calcium dependent and maximum agglutination was observed with rabbit erythrocytes. The hemagglutinating activity of the hepatopancreas lectin was effectively inhibited by sugars, such as α-lactose, GlcNAc, trehalose and NeuAc. Compared to sialylated N-glycosylated proteins including transferrin and apo transferrin, sialylated O-glycosylated proteins like fetuin exhibited stronger inhibitory effect. The ability of erythrocytes to bind hepatopancreas lectin has been diminished by desialylation of the potent inhibitor, indicating the significance of sialic acid in lectin-ligand interactions. The purified hepatopancreas lectin showed a broad spectrum of antimicrobial activity against bacteria Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, E. coli and fungi Candida albicans and Aspergillus niger. The findings of this study demonstrate the significance of hepatopancreas lectin as a multifunctional defense protein that inhibits the growth of bacteria and fungi.

Revisiting legume lectins: Structural organization and carbohydrate-binding properties

Legume lectins are a diverse family of carbohydrate-binding proteins that share significant similarities in their primary, secondary, and tertiary structures, yet exhibit remarkable variability in their quaternary structures and carbohydrate-binding specificities. The tertiary structure of legume lectins, characterized by a conserved β-sandwich fold, provides the scaffold for the formation of a carbohydrate-recognition domain (CRD) responsible for ligand binding. The structural basis for the binding is similar between members of the family, with key residues interacting with the sugar through hydrogen bonds, hydrophobic interactions, and van der Waals forces. Variability in substructures and residues within the CRD are responsible for the large array of specificities and enable legume lectins to recognize diverse sugar structures, while maintaining a consistent structural fold. Therefore, legume lectins can be classified into several specificity groups based on their preferred ligands, including mannose/glucose-specific, N-acetyl-d-galactosamine/galactose-specific, N-acetyl-d-glucosamine-specific, l-fucose-specific, and α-2,3 sialic acid-specific lectins. In this context, this review examined the structural aspects and carbohydrate-binding properties of representative legume lectins and their specific ligands in detail. Understanding the structure/binding relationships of lectins continues to provide valuable insights into their biological roles, while also assisting in the potential applications of these proteins in glycobiology, diagnostics, and therapeutics.

Wheat Germ Agglutinin (WGA): Its Nature, Biological Role, Significance in Human Nutrition, and Possibility to Be Used as Marker of Whole-Grain Status in Wheat-Based Foods

The growing scientific evidence on the health benefits of whole-grain food consumption has promoted the manufacturing of a great number of products differing in quality and content of whole-grain components. This is particularly true for commercial wheat-based products where it is not always clear how much whole wheat is present considering that in many cases, they are manufactured from reconstituted mill streams and that there is not a standardised globally accepted definition and metrics to objectively evaluate whole-grain status. Attempts have been made to assess the level of "wholegraininess" in wheat products by measuring specific constituents that correlate with different wheat tissues, especially those that are expected to be found in a true whole-grain wheat product. Wheat germ agglutinin (WGA), a small lectin protein present exclusively in the wheat-germ tissues, has been indicated by several scientists as one of these constituents and after founding that its level changes depending on the amount of germ found in a wheat flour, it has been indicated as a biomarker of whole-grain status for wheat products. In this review, the biochemistry of WGA, its methods of detection, and current knowledge on its possibility to be practically utilized as a reliable marker are critically discussed.

Dioclea violacea lectin has potent in vitro leishmanicidal activity against Leishmania infantum via carbohydrate recognition domain

Despite promising advancements in leishmaniasis treatment, existing therapies often face limitations and significant side effects, stimulating the search for novel therapeutic alternatives. In this context, lectins, such as DVL extracted from Dioclea violacea seeds, have emerged as potential candidates due to their diverse biological activities. This study represents the first investigation of the leishmanicidal potential of DVL in vitro against Leishmania infantum. Our results demonstrate that DVL exhibits a leishmanicidal effect (IC50/24 h = 49.37 μg/mL or 2 μM), binding to glycans on L. infantum. Fluorescence assays revealed that DVL can induce the production of reactive oxygen species (ROS) and cause damage to the parasite's membrane. DVL demonstrated a modulating effect when combined with amphotericin B and glucantime, enhancing the activity of these drugs by 40 % and 80 %, respectively. It also showed no cytotoxicity in Raw 264.7 cells and was able to override the toxic effect of amphotericin B on cells and reduce the survival rate of macrophages infected with amastigote forms, as well as their percentage of infection by 31 %. Therefore, DVL shows promise as a treatment for visceral leishmaniasis caused by L. infantum. Our findings provide valuable insights for future therapeutic development targeting leishmania glycans.

From sugar binders to diabetes fighters: the lectin saga of antihyperglycemic activity through systematic review and meta-analysis

Introduction

Lectins are carbohydrate-binding proteins that are extremely selective for sugar groups in the other molecules. As a result, they perform a variety of roles in biological processes involving cell, carbohydrate, and protein recognition at the cellular and molecular levels. Because lectins can bind to carbohydrates, they may play a role in determining the rate of carbohydrate digestion. They also bind to some proteins involved in diabetes mellitus (DM) pathophysiology. The present review aims to summarize the efficiency of lectins from different sources as potential antihyperglycemic agents.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were employed for the drafting. In this regard, published scientific articles on the effects of different lectins on blood glucose (BG), glucose tolerance, hormonal effects, carbohydrate-digesting enzymes, oxidative stress, and insulin production process were collected from reputed journals using electronic databases. Furthermore, the toxicity effects of lectins from different sources were collected. A specific keyword search was completed to collect numerous articles with unique experimental designs and significant results. This was followed by the selection of the requisite articles based on the criteria designed by the authors. Data extraction was based on the common research elements included in the articles.

Results and Discussion

Of 13 identified studies, 11 studies were considered after double screening based on the inclusion criteria. All 11 pharmacological investigations were considered for review. Subsequent studies reflected on the pharmacological properties of lectins on the levels of BG, oxidative stress, β-cell proliferation, insulin resistance, inhibition of carbohydrate digesting enzymes, body weight, food and water intake, lipid profile, and other parameters. This review highlights lectins as potential anti-diabetic agents.

Conclusion

However, due to limited research, systematic evaluation is recommended for their development and promotion as effective potential antihyperglycemic agents. The clinical efficacy and safety of lectins against diabetes mellitus must also be evaluated.

Concanavalin A, lectin from Canavalia ensiformis seeds has Leishmania infantum antipromastigote activity mediated by carbohydrate recognition domain

Leishmaniases, caused by Leishmania parasites, are widespread and pose significant health risks globally. Visceral leishmaniasis (VL) is particularly prevalent in Brazil, with high morbidity and mortality rates. Traditional treatments, such as pentavalent antimonials, have limitations due to toxicity and resistance. Therefore, exploring new compounds like lectins is crucial. Concanavalin A (ConA) has shown promise in inhibiting Leishmania growth. This study aimed to evaluate its leishmanicidal effect on L. infantum promastigotes and understand its mechanism of action. In vitro tests demonstrated inhibition of promastigote growth when treated with ConA, with IC50 values ranging from 3 to 5 μM over 24-72 h. This study suggests that ConA interacts with L. infantum glycans. Additionally, ConA caused damage to the membrane integrity of parasites and induced ROS production, contributing to parasite death. Scanning electron microscopy confirmed morphological alterations in treated promastigotes. ConA combined with the amphotericin B (AmB) showed synergistic effects, reducing the required dose of AmB, and potentially mitigating its toxicity. ConA demonstrated no cytotoxic effects on macrophages, instead stimulating their proliferation. These findings reinforce that lectin exhibits promising leishmanicidal activity against L. infantum promastigotes, making ConA a potential candidate for leishmaniasis treatment.

Phylogenetic variations in a novel family of hyperstable apple snail egg proteins: insights into structural stability and functional trends

The relationship between protein stability and functional evolution is little explored in proteins purified from natural sources. Here, we investigated a novel family of egg proteins (Perivitellin-1, PV1) from Pomacea snails. Their remarkable stability and clade-related functions in most derived clades (Canaliculata and Bridgesii) make them excellent candidates for exploring this issue. To that aim, we studied PV1 (PpaPV1) from the most basal lineage, Flagellata. PpaPV1 displays unparalleled structural and kinetic stability, surpassing PV1s from derived clades, ranking among the most hyperstable proteins documented in nature. Its spectral features contribute to a pale egg coloration, exhibiting a milder glycan binding lectin activity with a narrower specificity than PV1s from the closely related Bridgesii clade. These findings provide evidence for substantial structural and functional changes throughout the genus' PV1 evolution. We observed that structural and kinetic stability decreased in a clade-related fashion and was associated with large variations in defensive traits. For instance, pale PpaPV1 lectin turns potent in the Bridgesii clade, adversely affecting gut morphology, while giving rise to brightly colored PV1s providing eggs with a conspicuous, probably warning signal in the Canaliculata clade. This work provides a comprehensive comparative analysis of PV1s from various apple snail species within a phylogenetic framework, offering insights into the interplay among their structural features, stability profiles and functional roles. More broadly, our work provides one of the first examples from natural evolution showing the crucial link among protein structure, stability and evolution of new functions.

Adherence to a culturally adapted soul food vegan diet among African American adults increases diet quality compared to an omnivorous diet in the NEW Soul Study

Adherence to a vegan diet may lower risk of cardiovascular disease among African Americans (AAs). Feasibility and sustainability of adopting a vegan diet may be challenging among AAs who live in regions where soul food is a predominant cuisine. Our hypothesis was that AAs randomized to a culturally adapted vegan diet will have greater adherence to their assigned diet compared with those randomized to a culturally adapted omnivorous diet. AAs (N = 113) with overweight/obesity from South Carolina were included. Dietary intake was measured at months 0, 3, 6, and 12 using 24-hour recalls. Adherence was defined based on recommended animal product intake for each group. Differences in nutrient intakes and dietary indices (Alternative Healthy Eating Index 2010 and healthy plant-based diet index) between groups were evaluated using t-tests. At 12 months, adherence was higher to the vegan (51%) versus omnivorous (35%) diet. Participants assigned to the vegan diet had higher intake of carbohydrates (P = .01) and fiber (P < .001), and lower intake of cholesterol P< .001) and protein (P = .001) compared with participants assigned to the omnivorous diet. Participants adherent to the vegan diet had lower cholesterol intake (P < .001) and higher fiber intake (P = .02) compared with those adherent to the omnivorous diet. Compared with those assigned to the omnivorous diet, participants assigned to the vegan diet had higher Alternative Healthy Eating Index 2010 (P = .01) and healthy plant-based diet index (P < .001) scores. AAs with overweight/obesity were more adherent to a culturally adapted vegan diet versus an omnivorous diet after 1 year, and nutrient and food group intake changes were sustained.

Expression and antiviral application of exogenous lectin (griffithsin) in sweetpotatoes

Griffithsin (GRFT) is a highly effective, broad-spectrum, safe, and stable viral inhibitor used to suppress a variety of viruses. However, little information is available on whether GRFT can prevent plant viral diseases. In this study, we constructed a GRFT overexpression vector containing the sweetpotato storage cell signal peptide and generated exogenous GRFT overexpression lines through genetic transformation. The transgenic plants showed notable resistance to sweetpotato virus disease in the virus nursery. To verify the antiplant virus function of GRFT, transient expression in tobacco leaves showed that GRFT inhibited the sweetpotato leaf curl virus (SPLCV). The replication of SPLCV was entirely inhibited when the concentration of GRFT reached a certain level. The results of pulldown and BIFC assays showed that GRFT did not interact with the six components of SPLCV. In addition, the mutated GRFTD/A without the binding ability of carbohydrate and anticoronavirus function, in which three aspartate residues at carbohydrate binding sites were all mutated to alanine, also inhibited SPLCV. Quantitative reverse-transcription PCR analyses showed that the tobacco antiviral-related genes HIN1, ICS1, WRKY40, and PR10 were overexpressed after GRFT/GRFTD/A injection. Furthermore, HIN1, ICS1, and PR10 were more highly expressed in the leaves injected with GRFTD/A. The results suggest that sweetpotato is able to express GRFT exogenously as a bioreactor. Moreover, exogenous GRFT expression inhibits plant viruses by promoting the expression of plant antiviral genes.

Investigating diversity and similarity between CBM13 modules and ricin-B lectin domains using sequence similarity networks

BACKGROUND

The CBM13 family comprises carbohydrate-binding modules that occur mainly in enzymes and in several ricin-B lectins. The ricin-B lectin domain resembles the CBM13 module to a large extent. Historically, ricin-B lectins and CBM13 proteins were considered completely distinct, despite their structural and functional similarities.

RESULTS

In this data mining study, we investigate structural and functional similarities of these intertwined protein groups. Because of the high structural and functional similarities, and differences in nomenclature usage in several databases, confusion can arise. First, we demonstrate how public protein databases use different nomenclature systems to describe CBM13 modules and putative ricin-B lectin domains. We suggest the introduction of a novel CBM13 domain identifier, as well as the extension of CAZy cross-references in UniProt to guard the distinction between CAZy and non-CAZy entries in public databases. Since similar problems may occur with other lectin families and CBM families, we suggest the introduction of novel CBM InterPro domain identifiers to all existing CBM families. Second, we investigated phylogenetic, nomenclatural and structural similarities between putative ricin-B lectin domains and CBM13 modules, making use of sequence similarity networks. We concluded that the ricin-B/CBM13 superfamily may be larger than initially thought and that several putative ricin-B lectin domains may display CAZyme functionalities, although biochemical proof remains to be delivered.

CONCLUSIONS

Ricin-B lectin domains and CBM13 modules are associated groups of proteins whose database semantics are currently biased towards ricin-B lectins. Revision of the CAZy cross-reference in UniProt and introduction of a dedicated CBM13 domain identifier in InterPro may resolve this issue. In addition, our analyses show that several proteins with putative ricin-B lectin domains show very strong structural similarity to CBM13 modules. Therefore ricin-B lectin domains and CBM13 modules could be considered distant members of a larger ricin-B/CBM13 superfamily.

Glucose-Binding Dioclea bicolor Lectin (DBL): Purification, Characterization, Structural Analysis, and Antibacterial Properties

In this study, we purified a lectin isolated from the seeds of Dioclea bicolor (DBL) via affinity purification. Electrophoresis analysis revealed that DBL had three bands, α, β, and γ chains, with molecular masses of approximately 29, 14, and 12 kDa, respectively. Gel filtration chromatography revealed that the native form of DBL had a molecular mass of approximately 100 kDa, indicating that it is a tetramer. Interestingly, DBL-induced hemagglutination was inhibited by several glucosides, mannosides, ampicillin, and tetracycline with minimum inhibitory concentration (MIC) values of 1.56-50 mM. Analysis of the complete amino acid sequence of DBL revealed the presence of 237 amino acids with high similarity to other Diocleinae lectins. Circular dichroism showed the prominent β-sheet secondary structure of DBL. Furthermore, DBL structure prediction revealed a Discrete Optimized Protein Energy (DOPE) score of -26,642.69141/Normalized DOPE score of -1.84041. The DBL monomer was found to consist a β-sandwich based on its 3D structure. Molecular docking showed the interactions between DBL and α-D-glucose, N-acetyl-D-glucosamine, α-D-mannose, α-methyl-D-mannoside, ampicillin, and tetracycline. In addition, DBL showed antimicrobial activity with an MIC of 125 μg/mL and exerted synergistic effects in combination with ampicillin and tetracycline (fractional inhibitory concentration index ≤ 0.5). Additionally, DBL significantly inhibited biofilm formation and showed no toxicity in murine fibroblasts (p < 0.05). These results suggest that DBL exhibits antimicrobial activity and works synergistically with antibiotics.

Insights into the genetic architecture of Phytophthora capsici root rot resistance in chile pepper (Capsicum spp.) from multi-locus genome-wide association study

BACKGROUND

Phytophthora root rot, a major constraint in chile pepper production worldwide, is caused by the soil-borne oomycete, Phytophthora capsici. This study aimed to detect significant regions in the Capsicum genome linked to Phytophthora root rot resistance using a panel consisting of 157 Capsicum spp. genotypes. Multi-locus genome wide association study (GWAS) was conducted using single nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing (GBS). Individual plants were separately inoculated with P. capsici isolates, 'PWB-185', 'PWB-186', and '6347', at the 4-8 leaf stage and were scored for disease symptoms up to 14-days post-inoculation. Disease scores were used to calculate disease parameters including disease severity index percentage, percent of resistant plants, area under disease progress curve, and estimated marginal means for each genotype.

RESULTS

Most of the genotypes displayed root rot symptoms, whereas five accessions were completely resistant to all the isolates and displayed no symptoms of infection. A total of 55,117 SNP markers derived from GBS were used to perform multi-locus GWAS which identified 330 significant SNP markers associated with disease resistance. Of these, 56 SNP markers distributed across all the 12 chromosomes were common across the isolates, indicating association with more durable resistance. Candidate genes including nucleotide-binding site leucine-rich repeat (NBS-LRR), systemic acquired resistance (SAR8.2), and receptor-like kinase (RLKs), were identified within 0.5 Mb of the associated markers.

CONCLUSIONS

Results will be used to improve resistance to Phytophthora root rot in chile pepper by the development of Kompetitive allele-specific markers (KASP®) for marker validation, genomewide selection, and marker-assisted breeding.

The Potential Systemic Role of Diet in Dental Caries Development and Arrest: A Narrative Review

Current conceptualizations of dental caries etiology center primarily on the local role of sugar, starch, or other fermentable carbohydrates on tooth enamel demineralization-a well-established and empirically supported mechanism. However, in addition to this mechanism, studies dating back to the early 1900s point to an important systemic role of diet and nutrition, particularly from pasture-raised animal-source foods (ASF), in dental caries etiology and arrest. Findings from animal and human studies suggest that adherence to a diet high in calcium, phosphorus, fat-soluble vitamins A and D, and antioxidant vitamin C, as well as low in phytates, may contribute to arrest and reversal of dental caries, particularly among children. Furthermore, findings from observational and experimental studies of humans across the life-course suggest that fat-soluble vitamins A, D, and K2 may interact to protect against dental caries progression, even within a diet that regularly contains sugar. While these historic studies have not been revisited in decades, we emphasize the need for them to be reinvestigated and contextualized in the 21st century. Specifically, methodologically rigorous studies are needed to reinvestigate whether historical knowledge of systemic impacts of nutrition on dental health can help to inform current conceptualizations of dental caries etiology, prevention, and arrest.

Mannose-specific plant and microbial lectins as antiviral agents: A review

Lectins are non-immunological carbohydrate-binding proteins classified on the basis of their structure, origin, and sugar specificity. The binding specificity of such proteins with the surface glycan moiety determines their activity and clinical applications. Thus, lectins hold great potential as diagnostic and drug discovery agents and as novel biopharmaceutical products. In recent years, significant advancements have been made in understanding plant and microbial lectins as therapeutic agents against various viral diseases. Among them, mannose-specific lectins have being proven as promising antiviral agents against a variety of viruses, such as HIV, Influenza, Herpes, Ebola, Hepatitis, Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1), Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV) and most recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The binding of mannose-binding lectins (MBLs) from plants and microbes to high-mannose containing N-glycans (which may be simple or complex) of glycoproteins found on the surface of viruses has been found to be highly specific and mainly responsible for their antiviral activity. MBLs target various steps in the viral life cycle, including viral attachment, entry and replication. The present review discusses the brief classification and structure of lectins along with antiviral activity of various mannose-specific lectins from plants and microbial sources and their diagnostic and therapeutic applications against viral diseases.

Characterization of a Molecularly Engineered Banlec-Type Lectin (rBTL)

Lectins are proteins that reversibly bind to carbohydrates and are commonly found across many species. The Banana Lectin (BanLec) is a member of the Jacalin-related Lectins, heavily studied for its immunomodulatory, antiproliferative, and antiviral activity. In this study, a novel sequence was generated in silico considering the native BanLec amino acid sequence and 9 other lectins belonging to JRL. Based on multiple alignment of these proteins, 11 amino acids of the BanLec sequence were modified because of their potential for interference in active binding site properties resulting in a new lectin named recombinant BanLec-type Lectin (rBTL). rBTL was expressed in E. coli and was able to keep biological activity in hemagglutination assay (rat erythrocytes), maintaining similar structure with the native lectin. Antiproliferative activity was demonstrated on human melanoma lineage (A375), evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT). rBTL was able to inhibit cellular growth in a concentration-dependent manner, in an 8-h incubation, 12 µg/mL of rBTL led to a 28.94% of cell survival compared to cell control with 100%. Through a nonlinear fit out log-concentration versus biological response, an IC50% of 3.649 µg/mL of rBTL was determined. In conclusion, it is possible to state that the changes made to the rBTL sequence maintained the structure of the carbohydrate-binding site without changing specificity. The new lectin is biologically active, with an improved carbohydrate recognition spectrum compared to nBanLec, and can also be considered cytotoxic for A375 cells.

A Review of the Leishmanicidal Properties of Lectins

Lectins are proteins widely distributed among plants, animals and microorganisms that have the ability to recognize and interact with specific carbohydrates. They have varied biological activities, such as the inhibition of the progression of infections caused by fungi, bacteria, viruses and protozoa, which is related to the interaction of these proteins with the carbohydrates present in the cell walls of these microorganisms. Leishmaniasis are a group of endemic infectious diseases caused by protozoa of the genus Leishmania. In vitro and in vivo tests with promastigotes and amastigotes of Leishmania demonstrated that lectins have the ability to interact with glycoconjugates present on the cell surface of the parasite, it prevents their development through various mechanisms of action, such as the production of ROS and alteration of membrane integrity, and can also interact with defense cells present in the human body, thus showing that these molecules can be considered alternative pharmacological targets for the treatment of leishmaniasis. The objective of the present work is to carry out a bibliographic review on lectins with leishmanicidal activity, emphasizing the advances and perspectives of research in this theme. Through the analysis of the selected studies, we were able to conclude that lectins have great potential for inhibiting the development of leishmaniasis. However, there are still few studies on this subject.

Reversal mechanism of multidrug-resistant cancer cells by lectin as chemo-adjuvant and targeted therapy- a systematic review

BACKGROUND

Cancer is characterized as the leading cause of death, and the susceptibility of cancer cells to develop resistance due to long-term exposure to complementary chemotherapeutic treatment is referred to as multidrug resistance cancer cells (MDRC), which is a significant obstacle in the treatment of malignancies. Since complementary medicine lost its effectiveness, the development of potential alternative and novel therapeutic approaches has been elevated to a top priority in recent years. In this context, a bioactive protein lectin from plant and animal sources exhibits an invaluable source of anticancer agents with vast therapeutic potential.

PURPOSE

This manuscript's primary purpose is to enlighten the evidence-based (from 1986 to 2022) possible molecular mechanism of alternative treatment approaches using lectins over the complementary medicines used for cancer treatment.

METHODS

The PRISMA rules have been followed properly and qualitative and quantitative data are synthesized systematically. Articles were identified based on Clinical and preclinical reports published on lectin that investigated the in-depth cellular mechanisms, of reverse drug integrative oncology, as a nano-carried targeted delivery. Articles were systematically screened from 1986 to 2022 and selected based on electronic database searches, Medline (PubMed), Google Scholar, Web of Science, Encyclopaedias, Scopus, and ClinicalTrials.gov database.

RESULTS

The search turned up 4,212 publications from 38 different nations, of which 170 reference articles were used in our analysis, in 16 combination therapy and their mode of action, and 27 clinical trial studies including dosage and mechanism of action were included. Reports from the 30 lectins belonging to 28 different families have been included. The reversal mechanism of lectin and alternative therapy against MDRC is critically screened and according to a few clinical and preclinical reports, lectin can suppress the overexpressing genes like P-53, EGFR, and P-gp, MRP, and ABC transporter proteins associated with intracellular transportation of drugs. Since, the drug efflux mechanism leads to MDRC, in this phenomenon, lectin plays a key role in reversing the efflux mechanism. Few preclinical reports have mentioned that lectin shows synergism in combination with complementary medicine and as a nano drug carrier helps to deliver to the targeted site.

CONCLUSION

We have discussed the alternative therapy using lectin and an in-depth insight into the reversal drug resistance mechanisms to combat MDRC cancer, enhance the efficacy, reduce toxicity and adverse events, and ensure targeted delivery, and their application in the field of cancer diagnosis and prognosis has been discussed. However, further investigation is necessary in drug development and clinical trials which could be helpful to elaborate the reversal mechanism and unlock newer treatment modalities in MDRC cancer.

Genome-wide identification, classification, and characterization of lectin gene superfamily in sweet orange (Citrus sinensis L.)

Lectins are sugar-binding proteins found abundantly in plants. Lectin superfamily members have diverse roles, including plant growth, development, cellular processes, stress responses, and defense against microbes. However, the genome-wide identification and functional analysis of lectin genes in sweet orange (Citrus sinensis L.) remain unexplored. Therefore, we used integrated bioinformatics approaches (IBA) for in-depth genome-wide identification, characterization, and regulatory factor analysis of sweet orange lectin genes. Through genome-wide comparative analysis, we identified a total of 141 lectin genes distributed across 10 distinct gene families such as 68 CsB-Lectin, 13 CsLysin Motif (LysM), 4 CsChitin-Bind1, 1 CsLec-C, 3 CsGal-B, 1 CsCalreticulin, 3 CsJacalin, 13 CsPhloem, 11 CsGal-Lec, and 24 CsLectinlegB.This classification relied on characteristic domain and phylogenetic analysis, showing significant homology with Arabidopsis thaliana's lectin gene families. A thorough analysis unveiled common similarities within specific groups and notable variations across different protein groups. Gene Ontology (GO) enrichment analysis highlighted the predicted genes' roles in diverse cellular components, metabolic processes, and stress-related regulation. Additionally, network analysis of lectin genes with transcription factors (TFs) identified pivotal regulators like ERF, MYB, NAC, WRKY, bHLH, bZIP, and TCP. The cis-acting regulatory elements (CAREs) found in sweet orange lectin genes showed their roles in crucial pathways, including light-responsive (LR), stress-responsive (SR), hormone-responsive (HR), and more. These findings will aid in the in-depth molecular examination of these potential genes and their regulatory elements, contributing to targeted enhancements of sweet orange species in breeding programs.

New perspectives on different Sacha inchi seed oil extractions and its applications in the food and cosmetic industries

Sacha inchi oil is growing in demand worldwide owing to its high fatty acid content of linolenic acid (44.30%-51.62%) and linoleic acid (34.08%-36.13%). In addition, Sacha inchi oil also contains phytosterols, such as stigmasterols (346- 456 μg/g), sitosterols (435-563 μg/g), and campesterols (10.47% ± 4.36%). Its main tocopherol is gamma-tocopherol (120.41-125.69 mg/100 g). The antinutrients in Sacha inchi seeds can be reduced by roasting prior to extraction. Various extractions, including both conventional and novel methods, have been used to extract Sacha inchi oil. However, the variety of extraction methods and origins of the seeds change the nutrient profiles, antinutrient content, and physicochemical properties. Incorporation of Sacha inchi oil into food products can increase its nutritional value, and it works as a moisturizing agent in cosmetic products. To obtain Sacha inchi oil with the desired properties and nutritional profile, this review summarizes the effects of different Sacha inchi seed oil extraction methods and processes on chemical compounds, antinutrient content, and physicochemical properties, including their potential and recent applications in food and cosmetic industries.

Structural Analysis and Characterization of an Antiproliferative Lectin from Canavalia villosa Seeds

Cells use glycans to encode information that modulates processes ranging from cell-cell recognition to programmed cell death. This information is encoded within a glycocode, and its decoding is performed by carbohydrate-binding proteins. Among these, lectins stand out due to their specific and reversible interaction with carbohydrates. Changes in glycosylation patterns are observed in several pathologies, including cancer, where abnormal glycans are found on the surfaces of affected tissues. Given the importance of the bioprospection of promising biomolecules, the current work aimed to determine the structural properties and anticancer potential of the mannose-specific lectin from seeds of Canavalia villosa (Cvill). Experimental elucidation of the primary and 3D structures of the lectin, along with glycan array and molecular docking, facilitated the determination of its fine carbohydrate-binding specificity. These structural insights, coupled with the lectin's specificity, have been combined to explain the antiproliferative effect of Cvill against cancer cell lines. This effect is dependent on the carbohydrate-binding activity of Cvill and its uptake in the cells, with concomitant activation of autophagic and apoptotic pathways.

A Comprehensive Review on Euphorbiaceae lectins: Structural and Biological Perspectives

Euphorbiaceae, also known as the spurge family, is a large group of flowering plants. Despite being tropical natives, they are now widespread. Due to its medicinal and commercial importance, this family of plants attracted a lot of attention in the scientific community. The distinctive characteristic of the family is production of milky latex, which is a rich source of several lectins, the proteins that bind carbohydrates. Although their function is unclear, they are believed to defend plants against damaging phytopathogenic microorganisms, insects, and predatory animals. Additionally, they serve as crucial metabolic regulators under a variety of stressors. Detection, separation, purification, and characterization of lectins from the Euphorbiaceae family - mostly from the latex of plants - began over 40 years ago. This effort produced over 35 original research papers that were published. However, no systematic review that compiles these published data has been presented yet. This review summarizes and describes several procedures and protocols employed for extraction and purification of lectins belonging to this family. Physicochemical properties and biological activities of the lectins, along with their medicinal and pharmacological properties, have also been analyzed. Additionally, using examples of ricin and ricin agglutinin, we have structurally analyzed characteristics of the lectin known as Ribosome Inactivating Protein Type II (RIP-Type II) that belongs to this family. We anticipate that this review article will offer a useful compendium of information on this important family of lectins, show the scientists involved in lectin research the gaps in our knowledge, and offer insights for future research.

Diversity of transgenes in sustainable management of insect pests

Insecticidal transgenes, when incorporated and expressed in plants, confer resistance against insects by producing several products having insecticidal properties. Protease inhibitors, lectins, amylase inhibitors, and chitinase genes are associated with the natural defenses developed by plants to counter insect attacks. Several toxin genes are also derived from spiders and scorpions for protection against insects. Bacillus thuringiensis Berliner is a microbial source of insecticidal toxins. Several methods have facilitated the large-scale production of transgenic plants. Bt-derived cry, cyt, vip, and sip genes, plant-derived genes such as lectins, protease inhibitors, and alpha-amylase inhibitors, insect cell wall-degrading enzymes like chitinase and some proteins like arcelins, plant defensins, and ribosome-inactivating proteins have been successfully utilized to impart resistance to insects. Besides, transgenic plants expressing double-stranded RNA have been developed with enhanced resistance. However, the long-term effects of transgenes on insect resistance, the environment, and human health must be thoroughly investigated before they are made available for commercial planting. In this chapter, the present status, prospects, and future scope of transgenes for insect pest management have been summarized and discussed.

Emerging Roles of Receptor-like Protein Kinases in Plant Response to Abiotic Stresses

The productivity of plants is hindered by unfavorable conditions. To perceive stress signals and to transduce these signals to intracellular responses, plants rely on membrane-bound receptor-like kinases (RLKs). These play a pivotal role in signaling events governing growth, reproduction, hormone perception, and defense responses against biotic stresses; however, their involvement in abiotic stress responses is poorly documented. Plant RLKs harbor an N-terminal extracellular domain, a transmembrane domain, and a C-terminal intracellular kinase domain. The ectodomains of these RLKs are quite diverse, aiding their responses to various stimuli. We summarize here the sub-classes of RLKs based on their domain structure and discuss the available information on their specific role in abiotic stress adaptation. Furthermore, the current state of knowledge on RLKs and their significance in abiotic stress responses is highlighted in this review, shedding light on their role in influencing plant-environment interactions and opening up possibilities for novel approaches to engineer stress-tolerant crop varieties.

Defense Strategies of Rice in Response to the Attack of the Herbivorous Insect, Chilo suppressalis

Chilo suppressalis is a notorious pest that attacks rice, feeding throughout the entire growth period of rice and posing a serious threat to rice production worldwide. Due to the boring behavior and overlapping generations of C. suppressalis, the pest is difficult to control. Moreover, no rice variety with high resistance to the striped stem borer (SSB) has been found in the available rice germplasm, which also poses a challenge to controlling the SSB. At present, chemical control is widely used in agricultural production to manage the problem, but its effect is limited and it also pollutes the environment. Therefore, developing genetic resistance is the only way to avoid the use of chemical insecticides. This article primarily focuses on the research status of the induced defense of rice against the SSB from the perspective of immunity, in which plant hormones (such as jasmonic acid and ethylene) and mitogen-activated protein kinases (MAPKs) play an important role in the immune response of rice to the SSB. The article also reviews progress in using transgenic technology to study the relationship between rice and the SSB as well as exploring the resistance genes. Lastly, the article discusses prospects for future research on rice's resistance to the SSB.

DVL, lectin from Dioclea violacea seeds, has multiples mechanisms of action against Candida spp via carbohydrate recognition domain

Lectins are proteins of non-immunological origin with the ability to bind to carbohydrates reversibly. They emerge as an alternative to conventional antifungals, given the ability to interact with carbohydrates in the fungal cell wall inhibiting fungal growth. The lectin from D. violacea (DVL) already has its activity described as anti-candida in some species. Here, we observed the anti-candida effect of DVL on C. albicans, C. krusei and C. parapsilosis and its multiple mechanisms of action toward the yeasts. Additionally, it was observed that DVL induces membrane and cell wall damage and ROS overproduction. DVL was also able to cause an imbalance in the redox system of the cells, interact with ergosterol, inhibit ergosterol biosynthesis, and induce cytochrome c release from the mitochondrial membrane. These results endorse the potential application of DVL in developing a new antifungal drug to fight back against fungal resistance.

Wheat Pore-Forming Toxin-Like Protein Confers Broad-Spectrum Resistance to Fungal Pathogens in Arabidopsis

Fusarium head blight (FHB), caused by the hemibiotrophic fungus Fusarium graminearum, is one of the major threats to global wheat productivity. A wheat pore-forming toxin-like (PFT) protein was previously reported to underlie Fhb1, the most widely used quantitative trait locus in FHB breeding programs worldwide. In the present work, wheat PFT was ectopically expressed in the model dicot plant Arabidopsis. Heterologous expression of wheat PFT in Arabidopsis provided a broad-spectrum quantitative resistance to fungal pathogens including F. graminearum, Colletotrichum higginsianum, Sclerotinia sclerotiorum, and Botrytis cinerea. However, there was no resistance to bacterial or oomycete pathogens Pseudomonas syringae and Phytophthora capsici, respectively in the transgenic Arabidopsis plants. To explore the reason for the resistance response to, exclusively, the fungal pathogens, purified PFT protein was hybridized to a glycan microarray having 300 different types of carbohydrate monomers and oligomers. It was found that PFT specifically hybridized with chitin monomer, N-acetyl glucosamine (GlcNAc), which is present in fungal cell walls but not in bacteria or oomycete species. This exclusive recognition of chitin may be responsible for the specificity of PFT-mediated resistance to fungal pathogens. Transfer of the atypical quantitative resistance of wheat PFT to a dicot system highlights its potential utility in designing broad-spectrum resistance in diverse host plants. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Genome-Wide Mining of Selaginella moellendorffii for Hevein-like Lectins and Their Potential Molecular Mimicry with SARS-CoV-2 Spike Glycoprotein

Multidisciplinary research efforts on potential COVID-19 vaccine and therapeutic candidates have increased since the pandemic outbreak of SARS-CoV-2 in 2019. This search has become imperative due to the increasing emergences and limited widely available medicines. The presence of bioactive anti-SARS-CoV-2 molecules was examined from various plant sources. Among them is a group of proteins called lectins that can bind carbohydrate moieties. In this article, we present ten novel, chitin-specific Hevein-like lectins that were derived from Selaginella moellendorffii v1.0's genome. The capacity of these lectin homologs to bind with the spike protein of SARS-CoV-2 was examined. Using the HDOCK server, 3D-modeled Hevein-domains were docked to the spike protein's receptor binding domain (RBD). The Smo446851, Smo125663, and Smo99732 interacted with Asn343-located complex N-glycan and RBD residues, respectively, with binding free energies of -17.5, -13.0, and -26.5 Kcal/mol. The molecular dynamics simulation using Desmond and the normal-state analyses via torsional coordinate association for the Smo99732-RBD complex using iMODS is characterized by overall higher stability and minimum deformity than the other lectin complexes. The three lectins interacting with carbohydrates were docked against five individual mutations that frequently occur in major SARS-CoV-2 variants. These were in the spike protein's receptor-binding motif (RBM), while Smo125663 and Smo99732 only interacted with the spike glycoprotein in a protein-protein manner. The precursors for the Hevein-like homologs underwent additional characterization, and their expressional profile in different tissues was studied. These in silico findings offered potential lectin candidates targeting key N-glycan sites crucial to the virus's virulence and infection.

Phoenix dactylifera (date palm; Arecaceae) putative lectin homologs: Genome-wide search, architecture analysis, and evolutionary relationship

The date palm, Phoenix dactylifera, is a vital crop in nations in the Middle East and North Africa. The date palm was thought to have outstanding traditional medicinal value because it was abundant in phytochemicals with diverse chemical structures. The date palm's ability to withstand harsh environments could be partly attributed to a class of proteins known as lectins, which are carbohydrate-binding proteins that can bind sugar moieties reversibly and without changing their chemical structures. After scanning the genome of P. dactylifera (GCF 009389715.1), this in silico study discovered 196 possible lectin homologs from 11 different families, some specific to plants. At the same time, others could also be found in other kingdoms of life. Their domain architectures and functional amino acid residues were investigated, and they yielded a 40% true-lectin with known conserved carbohydrate-binding residues. Further, their probable subcellular localization, physiochemical and phylogenetic analyses were also performed. Scanning all putative lectin homologs against the anticancer peptide (ACP) dataset found in the AntiCP2.0 webpage identified 26 genes with protein kinase receptors (Lec-KRs) belonging to 5 lectin families, which are reported to have at least one ACP motif. Our study offers the first account of Phoenix-lectins and their organization that can be used for further structural and functional analysis and investigating their potential as anticancer proteins.

Identification of fusarium head blight resistance markers in a genome-wide association study of CIMMYT spring synthetic hexaploid derived wheat lines

Fusarium head blight (FHB), caused by Fusarium graminearum, is one of the most destructive wheat diseases worldwide. FHB infection can dramatically reduce grain yield and quality due to mycotoxins contamination. Wheat resistance to FHB is quantitatively inherited and many low-effect quantitative trait loci (QTL) have been mapped in the wheat genome. Synthetic hexaploid wheat (SHW) represents a novel source of FHB resistance derived from Aegilops tauschii and Triticum turgidum that can be transferred into common wheat (T. aestivum). In this study, a panel of 194 spring Synthetic Hexaploid Derived Wheat (SHDW) lines from the International Maize and Wheat Improvement Center (CIMMYT) was evaluated for FHB response under field conditions over three years (2017-2019). A significant phenotypic variation was found for disease incidence, severity, index, number of Fusarium Damaged Kernels (FDKs), and deoxynivalenol (DON) content. Further, 11 accessions displayed < 10 ppm DON in 2017 and 2019. Genotyping of the SHDW panel using a 90 K Single Nucleotide Polymorphism (SNP) chip array revealed 31 K polymorphic SNPs with a minor allele frequency (MAF) > 5%, which were used for a Genome-Wide Association Study (GWAS) of FHB resistance. A total of 52 significant marker-trait associations for FHB resistance were identified. These included 5 for DON content, 13 for the percentage of FDKs, 11 for the FHB index, 3 for disease incidence, and 20 for disease severity. A survey of genes associated with the markers identified 395 candidate genes that may be involved in FHB resistance. Collectively, our results strongly support the view that utilization of synthetic hexaploid wheat in wheat breeding would enhance diversity and introduce new sources of resistance against FHB into the common wheat gene pool. Further, validated SNP markers associated with FHB resistance may facilitate the screening of wheat populations for FHB resistance.

Isolation of Momordica charantia seed lectin and glycosidases from the protein bodies: Lectin-glycosidase (β-hexosaminidase) protein body membrane interaction reveals possible physiological function of the lectin

Momordica charantia seeds are known to contain a galactose specific lectin that has been well characterized. Seed extracts also contain glycosidases such as the β-hexosaminidase, α-mannosidase and α-galactosidase. In the present study, lectin was affinity purified from the seed extracts and protein bodies isolated by sucrose density gradient centrifugation. From the protein bodies, lectin was identified and β-hexosaminidase was isolated by lectin affinity chromatography and subsequently separated from other glycosidases by gel filtration. In the native PAGE, the purified β-hexosaminidase migrated as a single band with a molecular weight of ∼235 kDa and by zymogram analysis using 4-methylumbelliferyl N-acetyl-β-D-glucosaminide substrate it was confirmed as β-hexosaminidase. Under reducing conditions in SDS-PAGE, the purified enzyme dissociated into three bands (Mr 33, 20 and 15 kDa). The prominent bands (20 and 15 kDa) showed immunological cross-reactivity with the human Hexosaminidase B antibody in a western blot experiment. In gel digestion of the purified enzyme, followed by proteomic analysis using tandom MS/MS revealed sequence identity as compared to the genomic sequence of the Momordica charantia with a score of 57 (24% sequence coverage). Additionally, by CD analysis the purified β-hexosaminidase showed 39.1% of α-helix. Furthermore, secondary structure variations were observed in presence of substrate, lectin and at different pH values. Protein body membrane prepared from the isolated protein bodies showed a pH dependent interaction with the purified lectin and mixture of glycosidases.

Structure and interactions of the phloem lectin (phloem protein 2) Cus17 from Cucumis sativus

Phloem protein 2 (PP2) contributes crucially to phloem-based defense in plants by binding to carbohydrates displayed by pathogens. However, its three-dimensional structure and the sugar binding site remained unexplored. Here, we report the crystal structure of the dimeric PP2 Cus17 from Cucumis sativus in its apo form and complexed with nitrobenzene, N-acetyllactosamine, and chitotriose. Each protomer of Cus17 consists of two antiparallel four-stranded twisted β sheets, a β hairpin, and three short helices forming a β sandwich architectural fold. This structural fold has not been previously observed in other plant lectin families. Structure analysis of the lectin-carbohydrate complexes reveals an extended carbohydrate binding site in Cus17, composed mostly of aromatic amino acids. Our studies suggest a highly conserved tertiary structure and a versatile binding site capable of recognizing motifs common to diverse glycans on plant pathogens/pests, which makes the PP2 family suited for phloem-based plant defense.

A galactoside-specific Dalbergieae legume lectin from seeds of Vataireopsis araroba (Aguiar) Ducke

The Dalbergieae lectin group encompasses several lectins with significant differences in their carbohydrate specificities and biological properties. The current work reports on the purification and characterization of a GalNAc/Gal-specific lectin from Vataireopsis araroba (Aguiar) Ducke, designated as VaL. The lectin was purified from the seeds in a single step using guar gum affinity chromatography. The lectin migrated as a single band of about 35 kDa on SDS-PAGE and, in native conditions, occurs as a homodimer. The purified lectin is stable at temperatures up to 60 °C and in a pH range from 7 to 8 and requires divalent cations for its activity. Sugar-inhibition assays demonstrate the lectin specificity towards N-acetyl-D-galactosamine, D-galactose and related sugars. Furthermore, glycan array analyses show that VaL interacts preferentially with glycans containing terminal GalNAc/Galβ1-4GlcNAc. Biological activity assays were performed using three insect cell lines: CF1 midgut cells from the spruce budworm Choristoneura fumiferana, S2 embryo cells from the fruit fly Drosophila melanogaster, and GutAW midgut cells from the corn earworm Helicoverpa zea. In vitro assays indicated a biostatic effect for VaL on CF1 cells, but not on S2 and GutAW cells. The lectin presented a biostatic effect by reducing the cell growth and inducing cell agglutination, suggesting an interaction with glycans on the cell surface. VaL has been characterized as a galactoside-specific lectin of the Dalbergieae tribe, with sequence similarity to lectins from Vatairea and Arachis.

Seed Storage Protein, Functional Diversity and Association with Allergy

Plants are essential for humans as they serve as a source of food, fuel, medicine, oils, and more. The major elements that are utilized for our needs exist in storage organs, such as seeds. These seeds are rich in proteins, show a broad spectrum of physiological roles, and are classified based on their sequence, structure, and conserved motifs. With the improvements to our knowledge of the basic sequence and our structural understanding, we have acquired better insights into seed proteins and their role. However, we still lack a systematic analysis towards understanding the functional diversity associated within each family and their associations with allergy. This review puts together the information about seed proteins, their classification, and diverse functional roles along with their associations with allergy.

ArtinM Cytotoxicity in B Cells Derived from Non-Hodgkin's Lymphoma Depends on Syk and Src Family Kinases

Receptors on the immune cell surface have a variety of glycans that may account for the immunomodulation induced by lectins, which have a carbohydrate recognition domain (CRD) that binds to monosaccharides or oligosaccharides in a specific manner. ArtinM, a D-mannose-binding lectin obtained from Artocarpus heterophyllus, has affinity for the N-glycans core. Immunomodulation by ArtinM toward the Th1 phenotype occurs via its interaction with TLR2/CD14 N-glycans on antigen-presenting cells, as well as recognition of CD3γ N-glycans on murine CD4+ and CD8+ T cells. ArtinM exerts a cytotoxic effect on Jurkat human leukemic T-cell line and human myeloid leukemia cell line (NB4). The current study evaluated the effects of ArtinM on murine and human B cells derived from non-Hodgkin’s lymphoma. We found that murine B cells are recognized by ArtinM via the CRD, and the ArtinM stimulus did not augment the proliferation rate or production of IL-2. However, murine B cell incubation with ArtinM augmented the rate of apoptosis, and this cytotoxic effect of ArtinM was also seen in human B cell-lines sourced from non-Hodgkin’s lymphoma Raji cell line. This cytotoxic effect was inhibited by the phosphatase activity of CD45 on Lck, and the protein kinases of the Src family contribute to cell death triggered by ArtinM.

Plant Lectins: A Review on their Biotechnological Potential Toward Human Pathogens

The indiscriminate use of antibiotics is associated with the appearance of bacterial resistance. In light of this, plant-based products treating infections are considered potential alternatives. Lectins are a group of proteins widely distributed in nature, capable of reversibly binding carbohydrates. Lectins can bind to the surface of pathogens and cause damage to their structure, thus preventing host infection. The antimicrobial activity of plant lectins results from their interaction with carbohydrates present in the bacterial cell wall and fungal membrane. The data about lectins as modulating agents of antibiotic activity, potentiates the effect of antibiotics without triggering microbial resistance. In addition, lectins play an essential role in the defense against fungi, reducing their infectivity and pathogenicity. Little is known about the antiviral activity of plant lectins. However, their effectiveness against retroviruses and parainfluenza is reported in the literature. Some authors still consider mannose/ glucose/N-Acetylglucosamine binding lectins as potent antiviral agents against coronavirus, suggesting that these lectins may have inhibitory activity against SARS-CoV-2. Thus, it was found that plant lectins are an alternative for producing new antimicrobial drugs, but further studies still need to decipher some mechanisms of action.