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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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A lectin was isolated from the hepatopancreas of freshwater prawn, Macrobrachium rosenbergii by affinity chromatography using mucin-sepharose matrix. The purity of the isolated lectin was confirmed in native gradient PAGE that showed a single protein band of ∼37.9 kDa. In SDS-PAGE also one band of ∼43.3 kDa molecular weight was observed that indicated the protein to be a monomer. The band from the SDS-PAGE gel was identified through mass spectrometry as chitinase 1. The purified chitinase (50 μg/ml) hemagglutinated rabbit RBCs and, mucin and glucose inhibited hemagglutination with minimum concentrations of 0.1 mg/ml and 100 mM, respectively. Bacterial agglutination with Gram -ve Vibrio harveyi, Aeromonas sobria and Escherichia coli was also observed by this protein. Thus, chitinase 1 showed lectin-like properties besides its chitin hydrolytic activity. In western blot with hepatopancreas sample, rabbit antiserum against chitinase 1 cross-reacted to two additional proteins namely, chitinase 1C and obstructor E (a chitin-binding protein, CBP), besides its specific reactivity. An indirect ELISA was developed with the antiserum to quantify chitinases/CBP in hepatopancreas and serum samples of M. rosenbergii. The assay was used in samples from juvenile prawns following V. harveyi challenge. At 72 h post-challenge, significantly higher levels of chitinases/CBP were quantified in the hepatopancreas of the challenged group (1.8 ± 0.2 mg/g tissue) compared to the control (1.2 ± 0.1 mg/g tissue). This study suggests that the chitinase 1 protein with lectin-like properties is possibly induced at the protein level and can be putatively involved in the innate immune response of M. rosenbergii., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Marine algal lectins specific for high-mannose N -glycans have attracted attention because they strongly inhibit the entry of enveloped viruses, including influenza viruses and SARS-CoV-2, into host cells by binding to high-mannose-type N -glycans on viral surfaces. Here, we report a novel anti-influenza virus lectin (named HBL40), specific for complex-type N -glycans, which was isolated from a marine green alga, Halimeda borneensis . The hemagglutination activity of HBL40 was inhibited with both complex-type N -glycan and O -glycan-linked glycoproteins but not with high-mannose-type N -glycan-linked glycoproteins or any of the monosaccharides examined. In the oligosaccharide-binding experiment using 26 pyridylaminated oligosaccharides, HBL40 only bound to complex-type N -glycans with bi- and triantennary-branched sugar chains. The sialylation, core fucosylation, and the increased number of branched antennae of the N -glycans lowered the binding activity with HBL40. Interestingly, the lectin potently inhibited the infection of influenza virus (A/H3N2/Udorn/72) into NCI-H292 cells at IC 50 of 8.02 nM by binding to glycosylated viral hemagglutinin (K D of 1.21 × 10 -6 M). HBL40 consisted of two isolectins with slightly different molecular masses to each other that could be separated by reverse-phase HPLC. Both isolectins shared the same 16 N -terminal amino acid sequences. Thus, HBL40 could be useful as an antivirus lectin specific for complex-type N -glycans.

Haemonchus contortus is a hematophagous parasite that causes damage to ruminant production worldwide. This study reported the in vitro nematicidal effect of a lectin preparation (LP) isolated from Artocarpus heterophyllus seeds on larvae and adults of H. contortus. The protein extraction was in phosphate-buffered saline followed by protein precipitation with ammonium sulfate 70% and dialysis. The dialyzed protein fraction was chromatographed to obtain isolated LP. The LP was characterized by hemagglutinating activity (HA) assays, protein dosage and polyacrylamide gel electrophoresis. The motility index of H. contortus in the third larval stage (unsheathed L3 larvae) and adult stage was evaluated. The HA inhibition of LP by mannose and galactose as well as the electrophoretic profile indicated the presence of the lectins ArtinM and Jacalin. The motility index of H. contortus was significantly reduced (p < 0.001) during the first 8 h of LP exposure, both in larvae (lowest index 8.3% with LP at 1 mg mL -1 ) and female adults (lowest index 20% with LP at 500 μg mL -1 ; index 40% with LP at 1 mg mL -1 ). This research revealed that the LP has potential for being utilized in the development of natural nematicides., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Dietary food components have the ability to affect immune function; following absorption, specifically orally ingested dietary food containing lectins can systemically modulate the immune cells and affect the response to self- and co-administered food antigens. The mannose-binding lectins from garlic ( Allium sativum agglutinins; ASAs) were identified as immunodulatory proteins in vitro. The objective of the present study was to assess the immunogenicity and adjuvanticity of garlic agglutinins and to evaluate whether they have adjuvant properties in vivo for a weak antigen ovalbumin (OVA). Garlic lectins (ASA I and ASA II) were administered by intranasal (50 days duration) and intradermal (14 days duration) routes, and the anti-lectin and anti-OVA immune (IgG) responses in the control and test groups of the BALB/c mice were assessed for humoral immunogenicity. Lectins, co-administered with OVA, were examined for lectin-induced anti-OVA IgG response to assess their adjuvant properties. The splenic and thymic indices were evaluated as a measure of immunomodulatory functions. Intradermal administration of ASA I and ASA II had showed a four-fold and two-fold increase in anti-lectin IgG response, respectively, vs. the control on day 14. In the intranasal route, the increases were 3-fold and 2.4-fold for ASA I and ASA II, respectively, on day 50. No decrease in the body weights of animals was noticed; the increases in the spleen and thymus weights, as well as their indices, were significant in the lectin groups. In the adjuvanticity study by intranasal administration, ASA I co-administered with ovalbumin (OVA) induced a remarkable increase in anti-OVA IgG response (~six-fold; p < 0.001) compared to the control, and ASA II induced a four-fold increase vs. the control on day 50. The results indicated that ASA was a potent immunogen which induced mucosal immunogenicity to the antigens that were administered intranasally in BALB/c mice. The observations made of the in vivo study indicate that ASA I has the potential use as an oral and mucosal adjuvant to deliver candidate weak antigens. Further clinical studies in humans are required to confirm its applicability.

Marine algae are an excellent source of novel lectins. The isolation of lectins from marine algae expands the diversity in structure and carbohydrate specificities of lectins isolated from other sources. Marine algal lectins have been reported to have antiviral, antitumor, and antibacterial activity. Lectins are typically isolated from marine algae by grinding the algal tissue with liquid nitrogen and extracting with buffer and alcohol. While this method produces higher yields, it may not be sustainable for large-scale production, because a large amount of biomass is required to produce a minute amount of compound, and a significant amount of waste is generated during the extraction process. Therefore, non-destructive extraction using algal culture water could be used to ensure a continuous supply of lectins without exclusively disrupting the marine algae. This review discusses the traditional and recent advancements in algal lectin extraction methods over the last decade, as well as the steps required for large-scale production. The challenges and prospects of various extraction methods (destructive and non-destructive) are also discussed.

Rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), is one of the most destructive stored-product pests that is resistant to a wide range of chemical insecticides. In the present study, we investigated whether a lectin extracted from Polygonum persicaria L. (PPA) can be used as a biorational agent to control such insect pests. Along with the lethal digestive assay, the sub-lethal insecticidal activities of PPA, including the effects on digestive, detoxifying, and antioxidant enzyme activities, were evaluated against S. oryzae adults. The effect of feeding a diet containing PPA and carob extract as a food attractant on the mortality of S. oryzae adults was also investigated. Feeding on the diet containing PPA resulted in a significant mortality of S. oryzae adults with a LC 50 (Lethal Concentration to kill 50% of insects) of 3.68% ( w / w ). The activity of digestive enzymes, including α-amylase, α-glucosidase, TAG-lipase, trypsin, chymotrypsin, elastase, and carboxy- and aminopeptidase, were decreased by the sub-lethal concentration of PPA. Detoxifying and antioxidant enzymes, including esterase, superoxide dismutase, catalase, glutathione-S-transferase, ascorbate peroxidase, glucose 6-phosphate dehydrogenase, and malondialdehyde, were activated in adults affected by PPA. These findings indicated that PPA, in addition to causing digestive disorders, leads to oxidative stress in S. oryzae . The presence of carob extract had no effect on the PPA-induced mortality of the insect. According to the results of the present study, PPA has promising insecticidal efficiency against S. oryzae . In addition, the usage of PPA with a food attractant carob extract in bait traps can be recommended as a new biorational formulation in S . oryzae management.

Lectin is a carbohydrate-binding protein, which exhibits a plethora of biological properties such as antimicrobial, antifungal, and anticancer activities. In the present study, lectin, with an antibacterial and antioxidant potential, was purified from the oyster mushroom Pleurotus flabellatus. The P. flabellatus Lectin (PFL-L) was purified by using a DEAE - cellulose anion exchange chromatography followed by gel-filtration chromatography. The PFL-L was characterized by CD, HPLC, and MALDI-TOF/MS. The purity of PFL-L increased to 62.40% with the recovery of hemagglutinating activity (HA) by 12.12%. On SDS - PAGE, the PFL-L gave a single band of 18 kDa. PFL-L, consisting of d-galactose, exhibits a strong hemagglutinating activity. It was stable at pH (6.0-7.5) and temperature (10-20 °C) in addition to having extensive hemagglutinating activity. PFL-L enhanced the HA with the use of different metal ions namely Mg 2+ , Ca 2+, and Fe 2+ . The study of bacterial growth inhibition led to the inference that the PFL-L was more potent against gram-negative bacteria. PFL-L showed the highest radical scavenging activity for the DPPH assay at 100 μg/mL (89.9 ± 2.53%). The highest antioxidant activities with IC 50 values (for DPPH assay) of 53.96 μg/mL were determined for PFL-L and the present study shows that lectin from P. flabellatus manifested distinctive character and potentially exploitable activities., (Copyright © 2021. Published by Elsevier Inc.)

The increasing availability of sequenced genomes has enabled a deeper understanding of the complexity of fish lectin repertoires involved in early development and immune recognition. The teleost fucose-type lectin (FTL) family includes proteins that preferentially bind fucose and display tandemly arrayed carbohydrate-recognition domains (CRDs) or are found in mosaic combinations with other domains. They function as opsonins, promoting phagocytosis and the clearance of microbial pathogens. The Antarctic fish Trematomus bernacchii is a Perciforme living at extremely low temperatures (-1.68 °C) which is considered a model for studying adaptability to the variability of environmental waters. Here, we isolated a Ca ++ -independent fucose-binding protein from the serum of T. bernacchii by affinity chromatography with apparent molecular weights of 32 and 30 kDa under reducing and non-reducing conditions, respectively. We have characterized its carbohydrate binding properties, thermal stability and potential ability to recognize bacterial pathogens. In western blot analysis, the protein showed intense cross-reactivity with antibodies specific for a sea bass (Dicentrarchus labrax) fucose-binding lectin. In addition, its molecular and structural aspects, showing that it contains two CRD-FTLs confirmed that T. bernacchii FTL (TbFTL) is a bona fide member of the FTL family, with binding activity at low temperatures and the ability to agglutinate bacteria, thereby suggesting it participates in host-pathogen interactions in low temperature environments., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In this study, we examined aqueous extracts of the edible mushrooms Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (shiitake mushroom). Proteome analysis was conducted using LC-Triple TOF-MS and showed the expression of 753 proteins by Pleurotus ostreatus , and 432 proteins by Lentinula edodes . Bioactive peptides: Rab GDP dissociation inhibitor, superoxide dismutase, thioredoxin reductase, serine proteinase and lectin, were identified in both mushrooms. The extracts also included promising bioactive compounds including phenolics, flavonoids, vitamins and amino acids. The extracts showed promising antiviral activities, with a selectivity index (SI) of 4.5 for Pleurotus ostreatus against adenovirus (Ad7), and a slight activity for Lentinula edodes against herpes simplex-II (HSV-2). The extracts were not cytotoxic to normal human peripheral blood mononuclear cells (PBMCs). On the contrary, they showed moderate cytotoxicity against various cancer cell lines. Additionally, antioxidant activity was assessed using DPPH radical scavenging, ABTS radical cation scavenging and ORAC assays. The two extracts showed potential antioxidant activities, with the maximum activity seen for Pleurotus ostreatus (IC50 µg/mL) = 39.46 ± 1.27 for DPPH; 11.22 ± 1.81 for ABTS; and 21.40 ± 2.20 for ORAC assays. This study encourages the use of these mushrooms in medicine in the light of their low cytotoxicity on normal PBMCs vis à vis their antiviral, antitumor and antioxidant capabilities.

Vicieae tribe, Leguminosae family (Fabaceae), has been extensively studied. In particular, the study of lectins. The purification, physicochemical and structural characterizations of the various purified lectins and the analysis of their relevant biological activities are ongoing. In this review, several works already published about Vicieae lectins are addressed. Initially, we presented the purification protocols and the physicochemical aspects, such as specificity for carbohydrates, optimal activity in the face of variations in temperature and pH, as well metals-dependence. Following, structural characterization studies are highlighted and, finally, various biological activities already reported are summarized. Studies on lectins in almost all genera (Lathyrus, Lens, Pisum and Vicia) are considered, with the exception of Vavilovia which studies of lectins have not yet been reported. Like other leguminous lectins, Vicieae lectins present heterogeneous profiles of agglutination profiles for erythrocytes and other cells of the immune system, and glycoproteins. Most Vicieae lectins consist of two subunits, α and β, products of a single precursor protein derived from a single gene. The differences between the isoforms result from varying degrees of proteolytic processing. Along with the identification of these molecules and their characteristics, biological activities become very relevant and robust for both basic and applied research., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Betacoronaviruses, responsible for the "Severe Acute Respiratory Syndrome" (SARS) and the "Middle East Respiratory Syndrome" (MERS), use the spikes protruding from the virion envelope to attach and subsequently infect the host cells. The coronavirus spike (S) proteins contain receptor binding domains (RBD), allowing the specific recognition of either the dipeptidyl peptidase CD23 (MERS-CoV) or the angiotensin-converting enzyme ACE2 (SARS-Cov, SARS-CoV-2) host cell receptors. The heavily glycosylated S protein includes both complex and high-mannose type N -glycans that are well exposed at the surface of the spikes. A detailed analysis of the carbohydrate-binding specificity of mannose-binding lectins from plants, algae, fungi, and bacteria, revealed that, depending on their origin, they preferentially recognize either complex type N -glycans, or high-mannose type N -glycans. Since both complex and high-mannose glycans substantially decorate the S proteins, mannose-specific lectins are potentially useful glycan probes for targeting the SARS-CoV, MERS-CoV, and SARS-CoV-2 virions. Mannose-binding legume lectins, like pea lectin, and monocot mannose-binding lectins, like snowdrop lectin or the algal lectin griffithsin, which specifically recognize complex N -glycans and high-mannose glycans, respectively, are particularly adapted for targeting coronaviruses. The biomedical prospects of targeting coronaviruses with mannose-specific lectins are wide-ranging including detection, immobilization, prevention, and control of coronavirus infection.

Legumes are endowed with an opulent class of proteins called lectins that can detect tenuous variations in carbohydrate structures and bind them reversibly with high affinity and specificity. The genus Canavalia, in the family of Leguminosae, is considered to be an affluent source of lectin. An effort has been made to analyse the sequences encoded by the lectin gene and its carbohydrate binding pockets from three species of Canavalia, including C. virosa, C. rosea, and C. pubescens. Crude seed extract showed highest haemagglutination titer against buffalo RBCs and has high affinity to mannose and trehalose. Amplification of the lectin gene by gene-specific primers showed the presence of an 870 bp amplicon. Physicochemical characterization using various bioinformatic tools showed that the isoelectric point was below 7, suggesting that lectin molecules were acidic. A high aliphatic index and high instability index were observed, which indicated that lectin molecules were stable towards a wide range of temperatures. The occurrence of N-glycosylation sites at two sites was also identified in all three species. Prediction of secondary structure showed that approximately 59.05 %, 56.76 % and 54.88 % of the elements were random coils in the case of C. virosa, C. pubescens and C. rosea, respectively. Comparative modelling of the proteins and docking of hypothetical models with sugar moieties that inhibited the agglutination activity suggested that asparagine, serine, alanine, valine, tyrosine and threonine were the major residues involved in hydrogen bonding and other stacking interactions. This can further provide insights on its prospective antibiosis property., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The recently emerged COVID-19 disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has adversely affected the whole world. As a significant public health threat, it has spread worldwide. Scientists and global health experts are collaborating to find and execute speedy diagnostics, robust and highly effective vaccines, and therapeutic techniques to tackle COVID-19. The ocean is an immense source of biologically active molecules and/or compounds with antiviral-associated biopharmaceutical and immunostimulatory attributes. Some specific algae-derived molecules can be used to produce antibodies and vaccines to treat the COVID-19 disease. Algae have successfully synthesized several metabolites as natural defense compounds that enable them to survive under extreme environments. Several algae-derived bioactive molecules and/or compounds can be used against many diseases, including microbial and viral infections. Moreover, some algae species can also improve immunity and suppress human viral activity. Therefore, they may be recommended for use as a preventive remedy against COVID-19. Considering the above critiques and unique attributes, herein, we aimed to systematically assess algae-derived, biologically active molecules that could be used against this disease by looking at their natural sources, mechanisms of action, and prior pharmacological uses. This review also serves as a starting point for this research area to accelerate the establishment of anti-SARS-CoV-2 bioproducts.

Zizyphus mauritiana Lam. seeds (ZMS) have been used medicinally as sedative or hypnotic drugs in most of Asian countries. ZMS has significant benefits to the human health. Therefore, we have evaluated immunomodulatory effect of lectin extracted from these ZMSL in both in vitro and in vivo study. Anaphylaxis is a severe life-threatening allergic reaction and Arthus reaction is deposition of immune complex and complement system activation, so we hypothesized that if ZMSL can protect these severe allergic diseases. We have studied the effect of ZMSL on macrophages and Wistar albino rats and confirmed its protective effect against anaphylaxis and Arthus reaction. Results of this study suggest ZMSL have immunostimulatory and antiallergic activity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Vicia palaestina Boiss. is an annual herb that grows in dry areas of eastern Mediterranean countries. It belongs to section Cracca subgenus Vicilla, which is characterized by having a high content in the non-protein amino acid canavanine. The seeds from some of these vetches are also rich in lectins. The purification and characterization of a single-chain lectin from the seeds of V. palaestina is described here. This lectin was the most abundant protein in albumin extracts. It has affinity for the glycoconjugate N-acetylgalactosamine and inhibits proliferation of the cancerous Caco-2 and THP-1 cell lines. In addition to their high nutritional value, the seeds from V. palaestina represent a source of lectins with health promoting and pharmacological potential because of their antiproliferative activity., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

In the present study aimed to purify the lectin from the sap of Musa acuminata pseudostem and elucidate the apoptotic and angiogenic molecular mechanism in both in-vitro and in-vivo model. Mannose specific lectin was purified by using mannose affinity column chromatography and analyzed by RP-HPLC, SDS-PAGE, and PAS staining method. Furthermore, the protein was identified by MALDI-MS/MS. MAL effectively agglutinates trypsinized RBCs and showed effective cytotoxicity against various human cancer cell lines. MAL mitigates the cell proliferation, colony formation, cell migration, arrest the cell cycle in the G2/M phase, and induce apoptosis by altering the expression of apoptotic proteins/mRNA level (Bax and Bcl-2) via caspase 8/9, 3 dependent pathway in both in-vitro and in-vivo. Supporting this, in-vivo EAC tumor mice models prove the efficacy of MAL by inducing cell death and inhibiting the neovessel formation by targeting the MVD, inhibition of VEGF secretion, suppressing the expression of MMPs, HIF-1α, Flt-1, Akt, Jnk, and Erk1/2. More importantly, the MAL treatment leads to effective inhibition of tumor growth and an increase in the survivability of EAC mice. Our study summarizes that the MAL having a significant anticancer potential expressively degenerates the tumor development by inducing apoptosis and suppressing neoangiogenesis., (Copyright © 2020. Published by Elsevier B.V.)

Two novel β-trefoil lectins, MytiLec-1 and SeviL were found from mussels in the coast of Yokohama and Nagasaki. MytiLec-1 was purified from gill and mantle of Mytilus galloprovincialis. It was consisted of 149 amino acid residues and there was no similarity with any other proteins when it was discovered. We advocate for this "Mytilectin" as a new protein family because of their novelty of its primary structure and homologues were also found in other mussels. Glycan array analysis revealed that MytiLec-1 specifically bound to the Gb3 and Gb4 glycan which contained the α-galactoside. MytiLec-1 caused the apoptosis against the Burkitt's lymphoma cells through the interaction of Gb3 express in their cell surface. On the other hand, SeviL obtained from gill and mantle of Mytilisepta virgata showed the specific binding against GM1b, asialo GM1 and SSEA-4 which are known as glycosphingolipid glycan including the β-galactoside. In addition, SeviL was identified as R type lectin by confirmation of QXW motif within its primary structure. Messenger RNA of SeviL like R type lectins was also found among the musssels including Mytilus galloprovincialis. SeviL also showed the apoptosis against asialo GM1 expressing cells. To apply the anticancer lectin as a novel molecular target drug, primary structure of MytiLec-1 was analyzed to enhance the stabilization of confirmation by computational design technique. It was succeeded to produce a monomeric artificial β-trefoil lectin, Mitsuba-1 without losing the Gb3 binding ability. Comparison of biological function between Mitsuba-1 and MytiLec-1 is also described in this study.

Galectins are soluble lectins that participate in many physiological and pathological functions. Since they can act extracellularly, the use of the recombinant protein is a recurrent strategy for studying their biological functions. Here, we provide a general protocol for the production of Galectins and their isolated or chimeric domains. We take advantage of their lectin activity and the 6xHis-tag addition for purification, thus obtaining a highly pure and active Galectin to use in both in vitro and in vivo assays. For complete details on the use and execution of this protocol, please refer to Cattaneo et al. (2011), Tribulatti et al. (2012), and Prato et al. (2020)., Competing Interests: The authors declare no competing interests., (© 2020 The Author(s).)

Micrurus surinamensis (Cuvier, 1817), popularly known as aquatic coral snake, has a broad geographic distribution in the Rainforest of South America. The purpose of this study was to investigate the cytotoxic effect caused by M. surinamensis venom in H9c2 cardiomyoblast cells and to identify protein components involved in cardiotoxic processes. Venom cardiotoxic potential is evidenced by cell viability reduction in a concentration-dependent manner. We have purified one of venom components responsible for this effect after three chromatographic steps: a cytotoxic 23.461 kDa protein, as determined by mass spectrometry. A 19-residue sequence (DCPSGWSSYEGSCYNFFQR) of the purified protein was deduced by MS/MS and exhibited high homology with N-terminal region of C-type lectin from snake venoms. This protein was named Ms-CTL. Morphologically, H9c2 incubation with Ms-CTL led to a significant cellular retraction and formation of cellular aggregates, as observed by microscopy phase-contrast images. Our results indicate that M. surinamensis venom is highly toxic to H9c2 cardiomyoblast cell and less or not cytotoxic to other cell lines, such as HaCat, VERO and U373. Results presented herein will help understanding the mechanisms that underlie cellular damage and tissue destruction, being useful in the development of alternative therapies against these coral snake bites., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Drug resistance represents an obstacle in colorectal cancer (CRC) treatment because of its association with poor prognosis. rBC2LCN is a lectin isolated from Burkholderia that binds cell surface glycans that have fucose moieties. Because fucosylation is enhanced in many types of cancers, this lectin could be an efficient drug carrier if CRC cells specifically present such glycans. Therefore, we examined the therapeutic efficacy and toxicity of lectin drug conjugate therapy in CRC mouse xenograft models. The affinity of rBC2LCN for human CRC cell lines HT-29, LoVo, LS174T, and DLD-1 was assessed in vitro. The cytocidal efficacy of a lectin drug conjugate, rBC2LCN-38 kDa domain of pseudomonas exotoxin A (PE38) was evaluated by MTT assay. The therapeutic effects and toxicity for each CRC cell line-derived mouse xenograft model were compared between the intervention and control groups. LS174T and DLD-1 cell lines showed a strong affinity for rBC2LCN. In the xenograft model, the tumor volume in the rBC2LCN-PE38 group was significantly reduced compared with that using control treatment alone. However, the HT-29 cell line showed weak affinity and poor therapeutic efficacy. No significant toxicities or adverse responses were observed. In conclusion, we demonstrated that rBC2LCN lectin binds CRC cells and that rBC2LCN-PE38 significantly suppresses tumor growth in vivo. In addition, the efficacy of the drug conjugate correlated with its binding affinity for each CRC cell line. These results suggest that lectin drug conjugate therapy has potential as a novel targeted therapy for CRC cell surface glycans., (© 2020 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Lectins are a specialized group of proteins with immense biological properties and applications. This study describes the purification and characterization of a lectin from Leucaena leucocephala seeds, a plant belonging to the Fabaceae family. Leucaena leucocephala lectin (LLL) was purified by a two-step purification method involving DEAE-cellulose anion exchange chromatography and Sephadex G-75 size exclusion chromatography. The isolated lectin displayed a high haemagglutination titre upon treatment with rabbit erythrocytes. SDS-PAGE and Reverse-Phase High performance liquid chromatography (RP-HPLC) analysis experimentally revealed the presence of three bands corresponding to 37, 27 and 20 kDa indicating the presence of isolectins. Periodic Acid Schiff's (PAS) staining of LLL confirmed the presence of glycoprotein. Various biochemical parameters were analysed to study its effect on the haemagglutination activity. Sugar inhibition studies experimentally revealed that Glucose was the most potent inhibitor. Fluorescence spectrometric analysis of LLL and Glucose indicated a strong interaction with an association constant of 0.159 × 10 3  M -1 . Circular Dichroism spectroscopy indicated a higher alpha helical content (25.27%). LLL was observed to possess mitogenic activity against Peripheral blood mononuclear cells (PBMC). The present investigation reports the isolation of a novel lectin from this plant which could contribute towards the diagnostic studies of certain diseases and for its therapeutic potential., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Lectins are a group of widely distributed and structurally heterogeneous proteins of nonimmune origin. These proteins have the ability to interact with glycans present on cell surfaces and elicit diverse biological activities. Machaerium acutifolium lectin (MaL) is an N-acetyl-D-glucosamine-binding lectin that exhibits antinociceptive activity via transient receptor potential cation channel subfamily V member 1 (TRPV1). Lectins that have the ability to recognize and interact with N-acetyl-D-glucosamine residues are potential candidates for studies of fungicidal activity. In this work, we show that MaL has antifungal activity against Candida species, and we describe its mode of action towards Candida parapsilosis. MaL inhibited the growth of C. albicans and C. parapsilosis. However, MaL was more potent against C. parapsilosis. The candidacidal mode of action of MaL on C. parapsilosis involves enhanced cell permeabilization, alteration of the plasma membrane proton-pumping ATPase function (H+-ATPase), induction of oxidative stress, and DNA damage. MaL also exhibited antibiofilm activity and noncytotoxicity to Vero cells. These results indicate that MaL is a promising candidate for the future development of a new, natural, and safe drug for the treatment of infections caused by C. parapsilosis., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest regarding the publication of this article., (Copyright © 2020 Elsevier B.V. All rights reserved.)

An O-acetyl sialic acid specific lectin was purified from the hemolymph of the marine crab Atergatis integerrimus by affinity chromatography using BSM (Bovine Submaxillary Mucin) coupled to cyanogen bromide activated Sepharose 4B and biospecific adsorption using formalinized buffalo erythrocytes. The purified AiL (Atergatis integerrimus lectin) showed an 1218 fold increase in specific activity when compared to the crude hemolymph agglutinin. The lectin, on non - denaturing PAGE showed a single band of 216 kDa and when subjected to SDS - PAGE, the lectin resolved into three subunits of molecular weight 70, 72 and 74 kDa. Physico chemical characterization revealed the lectin as pH and temperature sensitive, calcium dependent and sensitive to calcium chelators. Based on the calcium dependency of the lectin, AiL could be classified as a C-type lectin. The purified lectin agglutinated buffalo erythrocytes with greater avidity and was inhibited by the glycoproteins BSM, thyroglobulin, fetuin, PSM, and sugars raffinose, trehalose, l - fucose, α - Lactose, melibiose and GluNAc suggesting the affinity of the lectin to sialic acid. Reduction in HA with asialo buffalo erythrocytes and HAI titer with desialylated BSM, confirms the sialic acid specificity of the lectin. The reduction in HAI following de - O - acetylation confirms the specificity of the lectin for O - acetyl sialic acid. FTIR analysis confirms the purified lectin as a glycoprotein with spectral bands corresponding to amide bands and saccharides. Thus this study paves way to assess the therapeutic application of this lectin that could be targeted to modified sialic acid moieties that are expressed on the malignant cells and pathogenic microbes and also deduce the crystal structure of the lectin., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Penaeid prawns are considered as most demanding fishery resources. The current study aims to purify and characterize lectin from the haemolymph of Penaeus semisulcatus. The semisulcatus-lectin was purified by affinity chromatography using mannose coupled Sepharose CL-4B column and purified lectin exhibited a single band of 66 kDa in SDS-PAGE. The purity and crystalline structure of purified lectin was confirmed by HPLC and X-ray diffraction analysis. Semisulcatus-lectin exhibited yeast agglutination activity against Saccharomyces cerevisiae and agglutinated human erythrocytes. Semisulcatus-lectin was evaluated for phenol oxidase activation and phagocytic activities. It was observed that semisulcatus-lectin had antibacterial activity against Gram-negative Vibrio parahaemolyticus and Aeromonas hydrophila, suggesting a potential therapeutic strategy in aquaculture industry for disease management., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Lectins are the oligomeric sugar-specific glycoprotein of nonimmune origin, are involved in the multiple biological recognition process, and have the capacity to perform a wide variety of physiological functions including antifungal, antiviral, antitumor, and cell agglutination. The main objective of the current study was to prepare lectin protein-loaded chitosan-TPP nanoparticles via ionic gelation methods with different CS/TPP ratios and to investigate anticancer potential against HepG2 cells. The best ratio showed the mean particle size (298.10 ± 1.9 nm, 21.05 ± 0.95 mv) with optimal encapsulation efficiencies of 52.435 ± 0.09%. The cytotoxicity was evaluated against HepG2 cells, and IC 50 values obtained were 265  μ g/ml for lectin protein and 105  μ g/ml for lectin-loaded chitosan-TPP nanoparticles, respectively. The mRNA expression of proliferation markers like GPC3 was significantly decreased in hepatocellular carcinoma cells (HepG2) during lectin protein-loaded chitosan-TPP nanoparticle treatment. Apoptotic genes that indicating a marked increase in expression are Caspase 3 , p53 , and Bax , while Bcl2 and AFP showed a downregulation of expression after treatment of HepG2 cells with lectin-loaded chitosan-TPP nanoparticles. The preliminary findings of our study highlighted that lectin protein-loaded chitosan-TPP nanoparticles could be a promising anticancer agent., Competing Interests: The authors declared no conflict of interest., (Copyright © 2020 Unzila Yasin et al.)

Lectins are proteins of non-immunological origin that may play several biological applications, of which we can highlight the anti-inflammatory and antinociceptive activities. In this work, we evaluated the possible effect of orofacial antinociceptive activity of three plant lectins, Dioclea violacea (DVL - Man/Glc-binding), Vatairea macrocarpa (VML - Gal-binding) and PPL (Parkia platycephala - Man/Glc-binding) in adult zebrafish. Acute nociception was induced by menthol (1.2 μM), or capsaicin (4.93 μM) applied into in the upper lip (5.0 μL) of adult wild zebrafish. Zebrafish were pretreated by intraperitoneal injection (20 μL) with vehicle (Control) or lectins (0.025; 0.05 or 0.1 mg/mL) 30 min before induction. The effect of lectins on zebrafish locomotor behavior was evaluated with the open field test. Naive groups (n = 8) were included in all tests. Our results indicate that only PPL presented antinociceptive induced by capsaicin, suggesting the potential clinical application of PPL as inhibitor of orofacial nociception and that this effect may be due to the modulation of TRPV1 channel. In conclusion, lectins that exhibit affinity to the same or different carbohydrates do not necessarily have an antinociceptive effect on the orofacial nociception model, indicating that the glycan carbohydrate binding pattern may be related to the effect on nociception inhibition., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Plant-derived dietary lectins have been reported to be involved in the pathogenesis of several inflammatory diseases, including hepatitis, inflammatory bowel disease, diabetes, and celiac disease. In this present study, we aimed to assess whether green tea polyphenols (GTPs) exerts protective effects against plant lectins-induced liver inflammation and immunological reaction in mice. The C57BL/6 mice received intragastric GTPs (200 mg/kg b.w.) once per day for 7 consecutive days prior to plant lectins stimulation (50 mg/kg b.w., intraperitoneally). GTPs supplementation alleviated the histopathological changes of liver and the disorder of serum biochemical parameters in plant lectins-challenged mice. GTPs supplementation also alleviated plant lectins-induced oxidative stress and liver inflammation, decreasing protein contents and gene expression levels of pro-inflammatory cytokines in the plasma and hepatic tissue and increasing antioxidant capacity in the liver. GTPs decreased the protein expression levels of myeloperoxidase, F4/80 and neutrophil, as determined by immunohistochemical analysis, and T lymphocytes (CD4 and CD8) contents as determined by immunofluorescence analysis, in the liver. Moreover, we found that GTPs inhibited Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome expression and increased nuclear factor erythroid 2-related factor 2 (Nrf2) pathways in the liver tissues of plant lectins-challenged mice. Taken together, these results show that GTPs alleviates hepatic inflammatory damage and immunological reaction after plant lectins challenge, and GTPs (or green tea intake) supplements can be beneficial for people exposed to plant lectins., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The emergence of the Coronavirus Disease 2019 (COVID-19) caused by the SARS-CoV-2 virus has led to an unprecedented pandemic, which demands urgent development of antiviral drugs and antibodies; as well as prophylactic approaches, namely vaccines. Algae biotechnology has much to offer in this scenario given the diversity of such organisms, which are a valuable source of antiviral and anti-inflammatory compounds that can also be used to produce vaccines and antibodies. Antivirals with possible activity against SARS-CoV-2 are summarized, based on previously reported activity against Coronaviruses or other enveloped or respiratory viruses. Moreover, the potential of algae-derived anti-inflammatory compounds to treat severe cases of COVID-19 is contemplated. The scenario of producing biopharmaceuticals in recombinant algae is presented and the cases of algae-made vaccines targeting viral diseases is highlighted as valuable references for the development of anti-SARS-CoV-2 vaccines. Successful cases in the production of functional antibodies are described. Perspectives on how specific algae species and genetic engineering techniques can be applied for the production of anti-viral compounds antibodies and vaccines against SARS-CoV-2 are provided.

This study investigated the effects of the alga lectin Hypnea cervicornis agglutinin (HCA) on rat zymosan-induced arthritis (ZyA). Zymosan (50-500 μg/25 μL) or sterile saline (Sham) was injected into the tibio-tarsal joint of female Wistar rats (180-200 g). Arthritic animals received morphine (4 mg/kg, intraperitoneal), indomethacin (5 mg/kg, intraperitoneal), or 2% lidocaine (100 μL, subcutaneous). HCA (0.3-3 mg/kg) was administered by intravenous route 30 min before or 2 h after zymosan. 1H-[1,2,4]oxadiazolo[4,3-a]-quinoxalin-1-one (ODQ, 4 μg, intra-articular) was given 30 min prior HCA. Hypernociception was measured every hour until 6 h, time in which animals were sacrificed for evaluation of leukocytes of the intra articular fluid and gene expression of TNF-α, IL-1, IL-10, and iNOS in the joint tissues using PCR techniques. Hypernociception was responsive to morphine and indomethacin, and its threshold was not altered by lidocaine. The post-treatment of HCA reduced both hypernociception and leukocyte influx. This antinociceptive effect was abolished either by ODQ and glibenclamide. HCA also reduced gene expression of iNOS and TNF-α. In conclusion, the antinociceptive effect of HCA in ZyA involves cyclic GMP signalization and selective modulation of cytokine expression.

A 15-kDa lectin, termed SeviL, was isolated from Mytilisepta virgata (purplish bifurcate mussel). SeviL forms a noncovalent dimer that binds strongly to ganglio-series GM1b oligosaccharide (Neu5Acɑ2-3Galβ1-3GalNAcβ1-4Galβ1-4Glc) and its precursor, asialo-GM1 (Galβ1-3GalNAcβ1-4Galβ1-4Glc). SeviL also interacts weakly with the glycan moiety of SSEA-4 hexaose (Neu5Acα2-3Galβ1-3GalNAcβ1-3Galα1-4Galβ1-4Glc). A partial protein sequence of the lectin was determined by mass spectrometry, and the complete sequence was identified from transcriptomic analysis. SeviL, consisting of 129 amino acids, was classified as an R(icin B)-type lectin, based on the presence of the QxW motif characteristic of this fold. SeviL mRNA is highly expressed in gills and, in particular, mantle rim tissues. Orthologue sequences were identified in other species of the family Mytilidae, including Mytilus galloprovincialis, from which lectin MytiLec-1 was isolated and characterized in our previous studies. Thus, mytilid species contain lectins belonging to at least two distinct families (R-type lectins and mytilectins) that have a common β-trefoil fold structure but differing glycan-binding specificities. SeviL displayed notable cytotoxic (apoptotic) effects against various cultured cell lines (human breast, ovarian, and colonic cancer; dog kidney) that possess asialo-GM1 oligosaccharide at the cell surface. This cytotoxic effect was inhibited by the presence of anti-asialo-GM1 oligosaccharide antibodies. With HeLa ovarian cancer cells, SeviL showed dose- and time-dependent activation of kinase MKK3/6, p38 MAPK, and caspase-3/9. The transduction pathways activated by SeviL via the glycosphingolipid oligosaccharide were triggered apoptosis. DATABASE: Nucleotide sequence data have been deposited in the GenBank database under accession numbers MK434191, MK434192, MK434193, MK434194, MK434195, MK434196, MK434197, MK434198, MK434199, MK434200, and MK434201., (© 2019 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Heparin-binding hemagglutinin (HBHA) from mycobacteria is involved in the dissemination of infection and the activation of the host immune response. However, the interaction of Nocardia cyriacigeorgica HBHA with the host cells remains unknown. In the present study, we describe N. cyriacigeorgica HBHA interactions with epithelial cells and organ colonization. We then investigate the mechanisms by which HBHA induces the production of inflammatory cytokines in macrophages. Immunofluorescent microscopy showed that HBHA adhered to A549 cells and HeLa cells and that the C-terminal fragment, which contains a Pro-Ala-Lys-rich domain, was responsible for adhesion. The deletion of the hbha gene in N. cyriacigeorgica mutant strains impaired adhesion to A549 cells and HeLa cells. In addition, the HBHA protein activated the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways and promoted the production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-10 in macrophages. HBHA-mediated TNF-α production was dependent on the activation of the c-Jun N-terminal kinase (JNK) signal pathways, and the IL-6 and IL-10 production was dependent on the activation of extracellular regulated kinase (ERK) 1/2, MAPK p38 (p38), JNK, and nuclear NF-κB signaling pathways. Additionally, the HBHA-mediated activation of innate immunity was dependent on Toll-like receptor 4 (TLR4). Taken together, these results indicate that N. cyriacigeorgica HBHA not only adheres to epithelial cells and may be involved in organ colonization, but also plays a critical role in the modulation of innate immunity through the MAPK and NF-κB signaling pathways via TLR4., (Copyright © 2020 Ji, Zhang, Sun, Hou, Song, Han, Xu, Li, Qiu, Li, Wang, Zheng and Li.)

Background: Lectins are proteins or glycoproteins of non-immune origin which bind specifically but reversibly to carbohydrates or glycoconjugates. They play a crucial role in various biological processes including host defense mechanism, inflammation and metastasis. Therefore, there is an expanding scientific emphasis on purification and characterization of novel lectins possessing different useful biological properties., Objective: The present investigation is concerned with purification and characterization of a novel lectin from the hemolymph of oak tasar (Antheraea proylei J.) silkworm., Methods: The lectin was purified from the hemolymph by a procedure involving successive steps of hemocyte-free hemolymph preparation, ammonium sulfate (0-40%) fractionation and affinity chromatography on a column of Sephadex G-50 covalently coupled with L-rhamnose. It was then characterized by various physico-chemical methods including SDS-PAGE, gel filtration, hemagglutination assay, hemagglutination inhibition assay and tandem mass spectrometry (LCMS/ MS) coupled with Mascot sequence matching software (Matrix Science)., Results: The lectin was purified to electrophoretic homogeneity from the silkworm hemolymph and was found to be a monomeric protein with a native molecular weight of 39.5 kDa. It was specifically inhibited by L-rhamnose and D-fucose, the former being sixteen times more inhibitory than the latter. The hemagglutinating activity was further characterized by independency of metal ion, optimum at pH 7-7.5 and thermal stability with t1/2 of 60°C. Analysis with tandem mass spectrometry coupled with Mascot sequence matching software confirmed the purified lectin to be a protein not purified and characterized earlier., Conclusion: A novel rhamnose/fucose-specific lectin was purified to electrophoretic homogeneity from the hemolymph of oak tasar (Antheraea proylei J.) silkworm. The lectin was found to be a monomeric protein with a native molecular weight of 39.5 kDa. Its activity was found to be independent of metal ion, optimum at pH 7-7.5 and characterized by thermal stability with t1/2 of 60°C. Analysis with tandem mass spectrometry coupled with Mascot sequence matching software confirmed the purified lectin to be a protein not characterized earlier., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Studies on the effects of components derived from the human pathogenic fungi Paracoccidioides brasiliensis have identified paracoccin (PCN), as a bifunctional protein with lectin (GlcNAc-binding) and enzymatic (chitinase) activities, able to induce modulation of host immune response. Endogenous PCN acts as a fungal virulence factor, whereas exogenous purified PCN, administered to the host, confers protective immunity in a murine model of paracoccidioidomycosis. The immunomodulation induced by purified-PCN injection has characterized it as an agent applicable in the therapy and vaccine against paracoccidioidomycosis. This section describes methods for PCN purification and validation of its lectin and enzymatic activities. It includes detailed protocols to obtain homogeneous PCN from P. brasiliensis yeasts, as well as to purify recombinant PCN from transformed heterologous microorganisms.

AJLec (18.5 kDa), a novel galactose-specific lectin, was isolated from the sea anemone Anthopleura japonica. AJLec demonstrates specificity for galactose monomers and β-linked terminal galactose residues in complex carbohydrates but not for N-acetylgalactosamine (GalNAc) which is commonly recognized by the galactose-binding lectins. Here, we have described the characteristics and process of extraction and purification of AJLec from Anthopleura japonica, which is useful for the analysis of complex carbohydrates.

The purification of fucose-binding lectins from the liver of striped bass (Morone saxatilis), a teleost fish, and the identification of a novel lectin sequence motif led to the identification of a new family of lectins, the F-type lectins (FTLs) (see overview of the FTL family in Chapter 23 ). Isolation and purification of these proteins from liver extracts of striped bass was accomplished by affinity chromatography and size exclusion, and their identification as FTLs, by direct Edman sequencing, and protein, transcript, and gene sequence analysis. The development of specific antibodies against the M. saxatilis FTL provided an additional tool for the identification of FTLs. These methods have been successfully used for the purification of the FTL family members from tissues and body fluids of various animal species. Production and characterization of FTLs has been facilitated by the expression of the recombinant proteins. In this chapter, the biochemical characterization of FTLs is focused on the analysis of their carbohydrate specificity.

Animal leguminous-type (L-type) lectins, including ERGIC-53 and VIP36 are responsible for intracellular transport and quality control of N-linked glycoproteins in the early secretory pathway. These lectins possess the carbohydrate recognition domain (CRD), which recognizes high-mannose-type glycans in a Ca 2+ -dependent manner. Here we describe the procedures involved in bacterial overproduction and purification of the CRDs of the animal L-type lectins.

Tachylectin-5, a 41-kDa protein with a common fold of the C-terminal globular domain of the γ-chain of fibrinogen, is purified from horseshoe crab hemolymph plasma by affinity column chromatography, using acetyl-group-immobilized resin. Two types of isolectins, tachylectin-5A and tachylectin-5B, are obtained by stepwise elution with GlcNAc at 25 and 250 mM, respectively. Tachylectins-5A and -5B exhibit extraordinarily strong hemagglutinating activity against all types of human erythrocytes (the minimum agglutinating concentration of 0.004-0.008 μg/mL for tachylectin-5A and 0.077-0.27 μg/mL for tachylectin-5B). Their hemagglutinating activities are inhibited by acetyl group-containing sugars and noncarbohydrates such as sodium acetate, acetylcholine, and acetyl CoA (the minimum inhibitory concentrations of 1.3-1.6 mM), indicating that the acetyl group is required and sufficient for recognition by tachylectins-5A and -5B. EDTA inhibits their hemagglutinating activity, whereas the inhibition is overcome by adding an excess amount of Ca 2+ . Tachylectins-5A and -5B also exhibit bacterial agglutinating activity against both Gram-negative bacteria (the minimum agglutinating concentrations of 0.04-0.08 μg/mL for tachylectin-5A and 0.05-0.11 μg/mL for tachylectin-5B) and Gram-positive bacteria (the minimum agglutinating concentrations of 0.3-2.4 μg/mL for tachylectin-5A and 15.1-26.8 μg/mL for tachylectin-5B). Interestingly, tachylectins-5A and -5B enhance the antimicrobial activity of a hemocyte-derived peptide, big defensin.

ZG16p is a soluble 16-kDa protein abundantly expressed in the pancreas and gut, and has a β-prism fold structure similar to that of mannose-binding Jacalin-related lectins (mJRLs) such as BanLec, Heltuba, and Artocarpin. ZG16p binds to mannose via the well-conserved GXXXD loop among mJRLs and sulfated glycosaminoglycans (e.g., heparin and heparan sulfate) via the basic patch of molecular surface. In addition to the above binding activities, ZG16p has inhibitory activity against proliferation of colon cancer cells. This manuscript describes purification of rat pancreatic ZG16p and recombinant ZG16p expressed in Escherichia coli expression system, and cell growth inhibition assay using ZG16p as an inhibitor.

Pleurotus cornucopiae mycelial lectin (PCL-M) is a divalent cation-dependent GalNAc-specific lectin that is purified from the mycelia of the edible mushroom Pleurotus cornucopiae. PCL-M is produced only in dikaryotic mycelia growing on solid medium and is not present in the mycelia of fruiting bodies. It is a multimeric glycoprotein composed of 40 kDa subunits linked by disulfide bonds. PCL-M is localized on the surface of aggregating mycelia and may be involved in primordia formation. The procedure for PCL-M purification has been discussed herein. Additionally, an experimental method for analyzing the localization of PCL-M on mycelial surface has been described.

Symbiosis with zooxanthellae is essential for survival of corals. Using a bioassay, we report the H-type lectin SLL-2 purified from the octocoral Sinularia lochmodes to restrict zooxanthellae form to spherical cells. However, the factor for initiating or maintaining a symbiotic relationship between a host and zooxanthellae has not been found in many corals. This bioassay is useful for evaluating the role of a lectin as a symbiosis-related factor.

Introduction: Tumor cells may present several molecular alterations that favor their malignancy, among which there is the expression of tumor-related antigens, such as truncated T-glycans, Thomsen-nouvelle, sialyl-Lewis X and sialyl Tn, which may help in the diagnosis and treatment using specific target molecules. Lectins are ubiquitous proteins capable of interacting with specific carbohydrates. Lectins isolated from marine organisms have important characteristics such as low immunogenicity and can bind to complex glycans compared to plant lectins., Objective: This work evaluated, through a systematic review, the molecular mechanisms of antitumor activity of lectins isolated from marine organisms., Methodology: The Pubmed, Lilacs, Science Direct, Wiley and Scopus databases were reviewed using the descriptors: marine lectin and cancer. Articles in English, published between January 2008 and December 2018, which proposed the molecular mechanisms of anticancer activity of lectins from marine organisms were eligible for the study., Results: 17 articles were eligible. The lectins showed promising performance against cancer cells, presenting specific cytotoxicity for some types of malignant cells. The articles presented several lectins specific to different carbohydrates, modulating: pro and anti-apoptotic proteins, transcription factor E2F-1, via mitogen-activated protein kinase. In addition, exogenous lectin expression in cancer cells has been shown to be a promising way to treat cancer., Conclusion: This review showed the various studies that described the molecular mechanisms caused by marine lectins with antineoplastic potential. This knowledge is relevant for the development and use of the next generations of lectins isolated from marine organisms, supporting their potential in cancer treatment., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Tachylectin-2, a 27-kDa protein consisting of a five-bladed β-propeller structure, is purified by three steps of chromatography, including dextran sulfate-Sepharose CL-6B, CM-Sepharose CL-6B, and Mono S. Three isolectins of tachylectin-2 including tachylectin-2a, -2b, and -2c are purified. These isolectins exhibit hemagglutinating activity against human A-type erythrocytes in a Ca 2+ -independent manner with tachylectin-2b showing the highest activity. Tachylectin-2b specifically agglutinates Staphylococcus saprophyticus KD. The tachylectin-2b-mediated hemagglutination is inhibited in the presence of GlcNAc and GalNAc. The association constants for GlcNAc and GalNAc are K a  = 1.95 × 10 4  M -1 and K a  = 1.11 × 10 3  M -1 , respectively. Ultracentrifugation analysis shows that tachylectin-2b is present in monomer form in solution.

Mushroom compounds and biomolecules are known for their biological beneficial effects and dietary properties. Their molecules can be used in immunology for their ability to stimulate immune cells and in biotherapy of diseases. In this study, the immunomodulatory effect using carbon clearance test in vivo of partial purified lectin of Lactarius deliciosus using DEAE-Sephacyl column, with sugar affinity against galactose, methyl-β-D-galactopyranoside and lactose, showed a significant effect on phagocytic activity and half-life of carbon particles in mice with different concentrations (5, 10, 15, and 30 mg/kg). The results showed that the immunomodulatory effect increased in low doses and decreased in high doses compared with the control group p < 0.0001. L. deliciosus lectin exerted a dose-dependent immunostimulant activity toward the reticulo-endothelial system, and phagocytic activity toward macrophages and neutrophils in spleen and liver against the colloidal carbon.

The partitioning and purification of lectins from the crude extract of Cratylia mollis seeds (Cramoll 1,4) was investigated in aqueous two-phase systems (ATPS). A factorial design model (2 4 ) was used to evaluate the influence of polyethylene glycol (PEG) molar mass (1500-8000 g/mol), PEG concentration (12.5-17.5% w/w), phosphate (10-15% w/w) concentration, and pH (6-8) on the differential partitioning, purification factor, and yield of the lectin. Polymer and salt concentration were the most important variables affecting partition of lectin and used to find optimum purification factor by experimental Box-Behnken design together with the response surface methodology (RSM). ATPS showed best conditions composed by 13.9% PEG1500, 15.3% phosphate buffer at pH 6, which ensured purification factor of 4.70. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band of protein with 26.1 kDa. Furthermore, results demonstrated a thermostable lectin presenting activity until 60 °C and lost hemagglutinating activity at 80 °C. According to the obtained data it can be inferred that the ATPS optimization using RSM approach can be applied for recovery and purification of lectins.

Background: Lectins are class of proteins characterized by their ability to selectively bind carbohydrate moieties of glycoproteins. Many invertebrate lectins, especially derived from hemolymph, are being purified, and yet their functions and medical applications are subjects of major interest., Methods: Hemolymph lectins in invertebrates play a major role in protecting against many pathogens and microbes. Further, many hemolymph lectins show anticancer properties towards various cancer cell lines, which expresses globotriaosyl ceramides on their cell surface., Results: These vast repertoires of hemolymph lectins in recognizing and inhibiting the growth of various harmful microbes and cancerous cells have spurred the biochemist to use them in histochemical and cytochemical studies., Conclusion: The present review will address the biological roles and biomedical applications of hemolymph lectin., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Penicillium griseoroseum lectin was 80-fold purified by successive DEAE Sepharose anion exchange and Sephadex G-100 gel permeation chromatography. P. griseoroseum lectin exhibited haemagglutination activity towards protease-treated rabbit erythrocytes. It showed specificity towards various carbohydrates such as d-mannose, N-acetyl-d-glucosamine, mucins, and so forth. P. griseoroseum lectin was found as a glycoprotein with glycan content of 4.33%. Purified P. griseoroseum lectin is homodimeric having a molecular mass of 57 kDa with subunit molecular mass of 28.6 kDa. Haemagglutination activity of purified P. griseoroseum lectin was completely stable from 25°C to 35°C at a pH range of 6-7.5. Lectin activity was not influenced by divalent metal ions and denaturants. P. griseoroseum lectin manifested mitogenicity towards mice splenocytes and activity reached a peak at 75 μg/ml of lectin concentration. P. griseoroseum lectin in microgram concentrations stimulated proliferation of mice splenocytes. Thus, P. griseoroseum lectin exhibits potential mitogenicity, which can be exploited for further biomedical applications., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This work aimed to evaluate the effects of CasuL on growth and viability of 15 mastitis isolates from cows and goats, to determine the synergistic potential between CasuL and antibiotics, and to investigate the effects on bacterial ultrastructure and antibiofilm activity. The lectin inhibited the growth of Staphylococcus isolates from either bovine (Ssp6PD and Sa) or caprine (Ssp5D and Ssp01) mastitis. The minimal inhibitory concentrations were ranged from 3.75 to 15 µg/ml. Synergistic effect was observed for CasuL-tetracycline against Sa and Ssp6PD and CasuL-ampicillin against Ssp01. No structural damage was observed under the scanning electron microscope in CasuL treatments. Flow cytometry analysis using thiazol orange and propidium iodide demonstrated that CasuL was unable to reduce the cell viability of the isolates tested. At sub-inhibitory concentrations, CasuL reduced biofilm formation by the isolates Sa and Ssp5D. However, CasuL-tetracycline and CasuL-ampicillin combinations inhibited biofilm formation by Ssp6PD and Ssp01, respectively. In conclusion, CasuL is a bacteriostatic and antibiofilm agent against some mastitis isolates and displayed a synergistic potential when used in combination with either ampicillin (against one isolate) or tetracycline (against two isolates). The results stimulate the evaluation of CasuL for the treatment of mastitis, particularly when used in conjunction with antibiotics., (© 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

A recently described bangle lectin (PHL) from the bacterium Photorhabdus asymbiotica was identified as a mainly fucose-binding protein that could play an important role in the host-pathogen interaction and in the modulation of host immune response. Structural studies showed that PHL is a homo-dimer that contains up to seven L-fucose-specific binding sites per monomer. For these reasons, potential ligands of the PHL lectin: α-L-fucopyranosyl-containing mono-, di-, tetra-, hexa- and dodecavalent ligands were tested. Two types of polyvalent structures were investigated - calix[4]arenes and dendrimers. The shared feature of all these structures was a C-glycosidic bond instead of the more common but physiologically unstable O-glycosidic bond. The inhibition potential of the tested structures was assessed using different techniques - hemagglutination, surface plasmon resonance, isothermal titration calorimetry, and cell cross-linking. All the ligands proved to be better than free L-fucose. The most active hexavalent dendrimer exhibited affinity three orders of magnitude higher than that of standard L-fucose. To determine the binding mode of some ligands, crystal complex PHL/fucosides 2 - 4 were prepared and studied using X-ray crystallography. The electron density in complexes proved the presence of the compounds in 6 out of 7 fucose-binding sites.

In the present study, chitin specific lectin was purified from fruit exudates of Praecitrullus fistulosus. The lectin was purified and analyzed using affinity chromatography, RP-HPLC and electrophoretic studies. Furthermore, protein was identified by MALDI-MS/MS and peptide mass fingerprinting. Purified lectin (PfL) effectively agglutinates RBC, lymphocytes and displayed strong cytotoxicity against colon cancer (line HT29) cells among screened cells. PfL induced apoptosis by altering the expression of apoptotic proteins via caspadse-3 dependent pathway. In vivo studies using EAC mice model proves the efficacy of PfL by activating apoptosis and inhibiting the tumor neovasculature by targeting the MVD, VEGF and MMP's secretion. More importantly, the PfL treatment leads to effective inhibition of tumor growth and a ∼2.71 fold increase in the lifespan of EAC mice. Collectively, our study provides comprehensive evidence that the role of dietary lectins with significant cytotoxic potential by targeting tumor angiogenesis and activating apoptosis in cancer study models., (Copyright © 2019 Elsevier Inc. All rights reserved.)