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Sample records for receptor c-type lectin

  1. Targeting C-Type Lectin Receptors for Cancer Immunity

    PubMed Central

    Yan, Huimin; Kamiya, Tomomori; Suabjakyong, Papawee; Tsuji, Noriko M.

    2015-01-01

    C-type lectin receptors (CLRs) are a large family of soluble and trans-membrane pattern recognition receptors that are widely and primarily expressed on myeloid cells. CLRs are important for cell–cell communication and host defense against pathogens through the recognition of specific carbohydrate structures. Similar to a family of Toll-like receptors, CLRs signaling are involved in the various steps for initiation of innate immune responses and promote secretion of soluble factors such as cytokines and interferons. Moreover, CLRs contribute to endocytosis and antigen presentation, thereby fine-tune adaptive immune responses. In addition, there may also be a direct activation of acquired immunity. On the other hand, glycans, such as mannose structures, Lewis-type antigens, or GalNAc are components of tumor antigens and ligate CLRs, leading to immunoregulation. Therefore, agonists or antagonists of CLRs signaling are potential therapeutic reagents for cancer immunotherapy. We aim to overview the current knowledge of CLRs signaling and the application of their ligands on tumor-associating immune response. PMID:26379663

  2. C-type lectins do not act as functional receptors for filovirus entry into cells

    SciTech Connect

    Matsuno, Keita; Nakayama, Eri; Noyori, Osamu; Marzi, Andrea; Ebihara, Hideki; Irimura, Tatsuro; Feldmann, Heinz; Takada, Ayato

    2010-12-03

    Research highlights: {yields} Filovirus glycoprotein (GP) having a deficient receptor binding region were generated. {yields} Mutant GPs mediated virus entry less efficiently than wild-type GP. {yields} Mutant GPs bound to C-type lectins but not mediated entire steps of cellular entry. {yields} C-type lectins do not independently mediate filovirus entry into cells. {yields} Other molecule(s) are required for C-type lectin-mediated entry of filoviruses. -- Abstract: Cellular C-type lectins have been reported to facilitate filovirus infection by binding to glycans on filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.

  3. Signaling by myeloid C-type lectin receptors in immunity and homeostasis

    PubMed Central

    Sancho, David; Reis e Sousa, Caetano

    2015-01-01

    Myeloid cells are key drivers of physiological responses to pathogen invasion or tissue damage. Members of the C-type lectin receptor (CLR) family stand out among the specialized receptors utilized by myeloid cells to orchestrate these responses. CLR ligands include carbohydrate, protein and lipid components of both pathogens and self, which variably trigger endocytic, phagocytic, pro-inflammatory or anti-inflammatory reactions. These varied outcomes rely on a versatile system for CLR signaling that includes tyrosine based motifs that recruit kinases, phosphatases or endocytic adaptors, as well as non-tyrosine based signals that modulate the activation of other pathways or couple to the uptake machinery. Here, we review the signaling properties of myeloid CLRs and how they impact the role of myeloid cells in innate and adaptive immunity. PMID:22224766

  4. Signalling versatility following self and non-self sensing by myeloid C-type lectin receptors

    PubMed Central

    Iborra, Salvador; Sancho, David

    2015-01-01

    Among myeloid immune receptors, C-type lectin receptors (CLRs) have a remarkable capacity to sense a variety of self and non-self ligands. The coupling of CLRs to different signal transduction modules is influenced not only by the receptor, but also by the nature, density and architecture of the ligand, which can affect the rate of receptor internalization and trafficking to diverse intracellular compartments. Understanding how the variety of self and non-self ligands triggers differential CLR signalling and function presents a fascinating biological challenge. Non-self ligands usually promote inflammation and immunity, whereas self ligands are frequently involved in communication and tolerance. But pathogens can mimic self-inhibitory signals to escape immune surveillance, and endogenous ligands can contribute to the sensing of pathogens through CLRs. In this review, we survey the complexity and flexibility in functional outcome found in the myeloid CLRs, which is not only based on their differing intracellular motifs, but is also conditioned by the physical nature, affinity and avidity of the ligand. PMID:25269828

  5. Computational and Experimental Prediction of Human C-Type Lectin Receptor Druggability

    PubMed Central

    Aretz, Jonas; Wamhoff, Eike-Christian; Hanske, Jonas; Heymann, Dario; Rademacher, Christoph

    2014-01-01

    Mammalian C-type lectin receptors (CTLRS) are involved in many aspects of immune cell regulation such as pathogen recognition, clearance of apoptotic bodies, and lymphocyte homing. Despite a great interest in modulating CTLR recognition of carbohydrates, the number of specific molecular probes is limited. To this end, we predicted the druggability of a panel of 22 CTLRs using DoGSiteScorer. The computed druggability scores of most structures were low, characterizing this family as either challenging or even undruggable. To further explore these findings, we employed a fluorine-based nuclear magnetic resonance screening of fragment mixtures against DC-SIGN, a receptor of pharmacological interest. To our surprise, we found many fragment hits associated with the carbohydrate recognition site (hit rate = 13.5%). A surface plasmon resonance-based follow-up assay confirmed 18 of these fragments (47%) and equilibrium dissociation constants were determined. Encouraged by these findings we expanded our experimental druggability prediction to Langerin and MCL and found medium to high hit rates as well, being 15.7 and 10.0%, respectively. Our results highlight limitations of current in silico approaches to druggability assessment, in particular, with regard to carbohydrate-binding proteins. In sum, our data indicate that small molecule ligands for a larger panel of CTLRs can be developed. PMID:25071783

  6. The evolution of HIV-1 interactions with coreceptors and mannose C-type lectin receptors.

    PubMed

    Borggren, Marie; Jansson, Marianne

    2015-01-01

    The phenotype of human immunodeficiency virus type 1 (HIV-1) commonly evolves between and within infected individuals, at virus transmission, and during disease progression. This evolution includes altered interactions between the virus and its coreceptors, i.e., chemokine receptors, as well as mannose C-type lectin receptors (CLRs). Transmitted/founder viruses are predominantly restricted to CCR5, whereas the subsequent intrapatient evolution of HIV-1 coreceptor use during progressive disease can be subdivided into two distinct pathways. Accordingly, the CCR5-restricted virus population is either gradually replaced by virus variants able to use CXCR4 or evolves toward an altered, more flexible use of CCR5. Despite a strong dependency on these coreceptors for host cell entry, HIV-1 also interacts with other cell surface molecules during target cell attachment, including the CLRs. The virus interaction with the CLRs may result either in the efficient transfer of virus to CD4(+) T cells or in the degradation of the virus in endosomal compartments. The determinants of the diverse outcomes depend on which CLR is engaged and also on the glycan makeup of the envelope glycoproteins, which may evolve with the strength of the immune pressure during the disease course. With the current clinical introduction of CCR5 antagonists and the development of additional entry inhibitors, knowledge on the evolution and baseline characteristics of HIV-1 interactions with coreceptor and CLR interactions may play important roles for individualized and optimized treatment strategies. This review summarizes our current understanding of the evolution of HIV-1 interactions with these receptors. PMID:25595802

  7. C-type Lectin Receptor Expression on Human Basophils and Effects of Allergen-Specific Immunotherapy.

    PubMed

    Lundberg, K; Rydnert, F; Broos, S; Andersson, M; Greiff, L; Lindstedt, M

    2016-09-01

    Basophils are emerging as immunoregulatory cells capable of interacting with their environment not only via their characteristic IgE-mediated activation, but also in an IgE-independent manner. Basophils are known to express and respond to stimulation via TLR2, TLR4, DC-SIGN and DCIR, but whether basophils also express other C-type lectin receptors (CLRs) is largely unknown. In this study, we investigate the CLR expression profile of human basophils using multicolour flow cytometry. As FcRs as well as some CLRs are associated with allergen recognition and shown to be involved in subsequent immune responses, the expression of CLRs and FcRs on peripheral blood basophils, as well as their frequency, was monitored for 1 year in subjects undergoing subcutaneous allergen-specific immunotherapy (AIT). Here, we show that human basophils express CLECSF14, DEC205, Dectin-1, Dectin-2 and MRC2. Furthermore, we demonstrate that the frequencies of basophils expressing the allergy-associated CLRs Dectin-1 and Dectin-2 were significantly reduced after 1 year and 8 weeks of AIT, respectively. In contrast, the frequency of basophils positive for FcγRII, as well as the fraction of total basophils, significantly increased after 1 year of AIT. The herein demonstrated expression of various CLRs on basophils, and their altered CLR and FcR expression profile upon AIT, suggest yet unexplored ways by which basophils can interact with antigens and may point to novel immunoregulatory functions targeted through AIT. PMID:27354239

  8. Molecular Characterization and Biological Effects of a C-Type Lectin-Like Receptor in Large Yellow Croaker (Larimichthys crocea)

    PubMed Central

    Ao, Jingqun; Ding, Yang; Chen, Yuanyuan; Mu, Yinnan; Chen, Xinhua

    2015-01-01

    The C-type lectin-like receptors (CTLRs) play important roles in innate immunity as one type of pattern recognition receptors. Here, we cloned and characterized a C-type lectin-like receptor (LycCTLR) from large yellow croaker Larimichthys crocea. The full-length cDNA of LycCTLR is 880 nucleotides long, encoding a protein of 215 amino acids. The deduced LycCTLR contains a C-terminal C-type lectin-like domain (CTLD), an N-terminal cytoplasmic tail, and a transmembrane region. The CTLD of LycCTLR possesses six highly conserved cysteine residues (C1–C6), a conserved WI/MGL motif, and two sugar binding motifs, EPD (Glu-Pro-Asp) and WYD (Trp-Tyr-Asp). Ca2+ binding site 1 and 2 were also found in the CTLD. The LycCTLR gene consists of five exons and four introns, showing the same genomic organization as tilapia (Oreochromis niloticus) and guppy (Poecilia retitculata) CTLRs. LycCTLR was constitutively expressed in various tissues tested, and its transcripts significantly increased in the head kidney and spleen after stimulation with inactivated trivalent bacterial vaccine. Recombinant LycCTLR (rLycCTLR) protein produced in Escherichia coli BL21 exhibited not only the hemagglutinating activity and a preference for galactose, but also the agglutinating activity against two food-borne pathogenic bacteria E. coli and Bacillus cereus in a Ca2+-dependent manner. These results indicate that LycCTLR is a potential galactose-binding C-type lectin that may play a role in the antibacterial immunity in fish. PMID:26690423

  9. Molecular Characterization and Biological Effects of a C-Type Lectin-Like Receptor in Large Yellow Croaker (Larimichthys crocea).

    PubMed

    Ao, Jingqun; Ding, Yang; Chen, Yuanyuan; Mu, Yinnan; Chen, Xinhua

    2015-01-01

    The C-type lectin-like receptors (CTLRs) play important roles in innate immunity as one type of pattern recognition receptors. Here, we cloned and characterized a C-type lectin-like receptor (LycCTLR) from large yellow croaker Larimichthys crocea. The full-length cDNA of LycCTLR is 880 nucleotides long, encoding a protein of 215 amino acids. The deduced LycCTLR contains a C-terminal C-type lectin-like domain (CTLD), an N-terminal cytoplasmic tail, and a transmembrane region. The CTLD of LycCTLR possesses six highly conserved cysteine residues (C1-C6), a conserved WI/MGL motif, and two sugar binding motifs, EPD (Glu-Pro-Asp) and WYD (Trp-Tyr-Asp). Ca(2+) binding site 1 and 2 were also found in the CTLD. The LycCTLR gene consists of five exons and four introns, showing the same genomic organization as tilapia (Oreochromis niloticus) and guppy (Poecilia retitculata) CTLRs. LycCTLR was constitutively expressed in various tissues tested, and its transcripts significantly increased in the head kidney and spleen after stimulation with inactivated trivalent bacterial vaccine. Recombinant LycCTLR (rLycCTLR) protein produced in Escherichia coli BL21 exhibited not only the hemagglutinating activity and a preference for galactose, but also the agglutinating activity against two food-borne pathogenic bacteria E. coli and Bacillus cereus in a Ca(2+)-dependent manner. These results indicate that LycCTLR is a potential galactose-binding C-type lectin that may play a role in the antibacterial immunity in fish. PMID:26690423

  10. Abundant expression of HIV target cells and C-type lectin receptors in the foreskin tissue of young Kenyan men.

    PubMed

    Hirbod, Taha; Bailey, Robert C; Agot, Kawango; Moses, Stephen; Ndinya-Achola, Jeckoniah; Murugu, Ruth; Andersson, Jan; Nilsson, Jakob; Broliden, Kristina

    2010-06-01

    A biological explanation for the reduction in HIV-1 (HIV) acquisition after male circumcision may be that removal of the foreskin reduces the number of target cells for HIV. The expression of potential HIV target cells and C-type lectin receptors in foreskin tissue of men at risk of HIV infection were thus analyzed. Thirty-three foreskin tissue samples, stratified by Herpes simplex virus type 2 status, were obtained from a randomized, controlled trial conducted in Kenya. The samples were analyzed by confocal in situ imaging microscopy and mRNA quantification by quantitative RT-qPCR. The presence and location of T cells (CD3(+)CD4(+)), Langerhans cells (CD1a(+)Langerin/CD207(+)), macrophages (CD68(+) or CD14(+)), and submucosal dendritic cells (CD123(+)BDCA-2(+) or CD11c(+)DC-SIGN(+)) were defined. C-type lectin receptor expressing cells were detected in both the epithelium and submucosa, and distinct lymphoid aggregates densely populated with CD3(+)CD4(+) T cells were identified in the submucosa. Although the presence of lymphoid aggregates and mRNA expression of selected markers varied between study subjects, Herpes simplex virus type 2 serostatus was not the major determinant for the detected differences. The detection of abundant and superficially present potential HIV target cells and submucosal lymphoid aggregates in foreskin mucosa from a highly relevant HIV risk group demonstrate a possible anatomical explanation that may contribute to the protective effect of male circumcision on HIV transmission. PMID:20395432

  11. Scavenger Receptor C-Type Lectin Binds to the Leukocyte Cell Surface Glycan Lewis By a Novel Mechanism

    SciTech Connect

    Feinberg, H.; Taylor, M.E.; Weis, W.I.; /Stanford U., Med. School /Imperial Coll., London

    2007-07-10

    The scavenger receptor C-type lectin (SRCL) is unique in the family of class A scavenger receptors, because in addition to binding sites for oxidized lipoproteins it also contains a C-type carbohydrate-recognition domain (CRD) that interacts with specific glycans. Both human and mouse SRCL are highly specific for the Lewis(x) trisaccharide, which is commonly found on the surfaces of leukocytes and some tumor cells. Structural analysis of the CRD of mouse SRCL in complex with Lewis(x) and mutagenesis show the basis for this specificity. The interaction between mouse SRCL and Lewis(x) is analogous to the way that selectins and DC-SIGN bind to related fucosylated glycans, but the mechanism of the interaction is novel, because it is based on a primary galactose-binding site similar to the binding site in the asialoglycoprotein receptor. Crystals of the human receptor lacking bound calcium ions reveal an alternative conformation in which a glycan ligand would be released during receptor-mediated endocytosis.

  12. Efficient generation of a monoclonal antibody against the human C-type lectin receptor DCIR by targeting murine dendritic cells

    PubMed Central

    Heidkamp, Gordon F.; Neubert, Kirsten; Haertel, Eric; Nimmerjahn, Falk; Nussenzweig, Michel C.; Dudziak, Diana

    2010-01-01

    1. Summary Dendritic cells (DCs) are very important for the generation of long lasting immune responses against pathogens or the induction of anti-tumor responses. Targeting antigen to dendritic cells via monoclonal antibodies specific for DC cell surface receptors such as DEC205 was shown to elicit potent cellular and humoral immune responses in vivo. Therefore we investigated whether this novel strategy might also be useful for the generation of new monoclonal antibodies against molecules of choice. We show, that by targeting the extracellular domain of the human C-type lectin receptor ClecSF6/DCIR/LLIR (hDCIR) to DEC205 on DCs in vivo, we were able to generate highly specific monoclonal antibodies against hDCIR. PMID:20566350

  13. Lectin-dependent enhancement of Ebola virus infection via soluble and transmembrane C-type lectin receptors.

    PubMed

    Brudner, Matthew; Karpel, Marshall; Lear, Calli; Chen, Li; Yantosca, L Michael; Scully, Corinne; Sarraju, Ashish; Sokolovska, Anna; Zariffard, M Reza; Eisen, Damon P; Mungall, Bruce A; Kotton, Darrell N; Omari, Amel; Huang, I-Chueh; Farzan, Michael; Takahashi, Kazue; Stuart, Lynda; Stahl, Gregory L; Ezekowitz, Alan B; Spear, Gregory T; Olinger, Gene G; Schmidt, Emmett V; Michelow, Ian C

    2013-01-01

    Mannose-binding lectin (MBL) is a key soluble effector of the innate immune system that recognizes pathogen-specific surface glycans. Surprisingly, low-producing MBL genetic variants that may predispose children and immunocompromised individuals to infectious diseases are more common than would be expected in human populations. Since certain immune defense molecules, such as immunoglobulins, can be exploited by invasive pathogens, we hypothesized that MBL might also enhance infections in some circumstances. Consequently, the low and intermediate MBL levels commonly found in human populations might be the result of balancing selection. Using model infection systems with pseudotyped and authentic glycosylated viruses, we demonstrated that MBL indeed enhances infection of Ebola, Hendra, Nipah and West Nile viruses in low complement conditions. Mechanistic studies with Ebola virus (EBOV) glycoprotein pseudotyped lentiviruses confirmed that MBL binds to N-linked glycan epitopes on viral surfaces in a specific manner via the MBL carbohydrate recognition domain, which is necessary for enhanced infection. MBL mediates lipid-raft-dependent macropinocytosis of EBOV via a pathway that appears to require less actin or early endosomal processing compared with the filovirus canonical endocytic pathway. Using a validated RNA interference screen, we identified C1QBP (gC1qR) as a candidate surface receptor that mediates MBL-dependent enhancement of EBOV infection. We also identified dectin-2 (CLEC6A) as a potentially novel candidate attachment factor for EBOV. Our findings support the concept of an innate immune haplotype that represents critical interactions between MBL and complement component C4 genes and that may modify susceptibility or resistance to certain glycosylated pathogens. Therefore, higher levels of native or exogenous MBL could be deleterious in the setting of relative hypocomplementemia which can occur genetically or because of immunodepletion during active

  14. SHP-2 Mediates C-type Lectin Receptors-induced Syk Activation and Anti-fungal TH17 Responses

    PubMed Central

    Deng, Zihou; Ma, Shixin; Zhou, Hao; Zang, Aiping; Fang, Yiyuan; Li, Tiantian; Shi, Huanjing; Liu, Mei; Du, Min; Taylor, Patricia R.; Zhu, Helen H.; Chen, Jiangye; Meng, Guangxun; Li, Fubin; Chen, Changbin; Zhang, Yan; Jia, Xin-Ming; Lin, Xin; Zhang, Xiaoming; Pearlman, Eric; Li, Xiaoxia; Feng, Gen-Sheng; Xiao, Hui

    2015-01-01

    SUMMARY Fungal infection stimulates the canonical C-type lectin receptors (CLRs) signaling pathway via Syk activation. Here we show that SHP-2 plays a crucial role in mediating CLRs-induced Syk activation. Genetic ablation of Shp-2 (Ptpn11) in dendritic cells (DCs) and macrophages impaired Syk-mediated signaling and abrogated pro-inflammatory gene expression following fungal stimulation. Mechanistically, SHP-2 operates as a scaffold facilitating the recruitment of Syk to dectin-1 or FcRγ, through its N-SH2 domain and a previously unrecognized C-terminal ITAM motif. We demonstrate that DC-derived SHP-2 is crucial for the induction of IL-1β, IL-6 and IL-23, and anti-fungal TH17 cell responses to control Candida albicans infection. Together, these data reveal a mechanism by which SHP-2 mediates Syk activation in response to fungal infections PMID:25915733

  15. Mechanistic Insights into the Role of C-Type Lectin Receptor/CARD9 Signaling in Human Antifungal Immunity.

    PubMed

    Drummond, Rebecca A; Lionakis, Michail S

    2016-01-01

    Human CARD9 deficiency is an autosomal recessive primary immunodeficiency disorder caused by biallelic mutations in the gene CARD9, which encodes a signaling protein that is found downstream of many C-type lectin receptors (CLRs). CLRs encompass a large family of innate recognition receptors, expressed predominantly by myeloid and epithelial cells, which bind fungal carbohydrates and initiate antifungal immune responses. Accordingly, human CARD9 deficiency is associated with the spontaneous development of persistent and severe fungal infections that primarily localize to the skin and subcutaneous tissue, mucosal surfaces and/or central nervous system (CNS). In the last 3 years, more than 15 missense and nonsense CARD9 mutations have been reported which associate with the development of a wide spectrum of fungal infections caused by a variety of fungal organisms. The mechanisms by which CARD9 provides organ-specific protection against these fungal infections are now emerging. In this review, we summarize recent immunological and clinical advances that have provided significant mechanistic insights into the pathogenesis of human CARD9 deficiency. We also discuss how genetic mutations in CARD9-coupled receptors (Dectin-1, Dectin-2) and CARD9-binding partners (MALT1, BCL10) affect human antifungal immunity relative to CARD9 deficiency, and we highlight major understudied research questions which merit future investigation. PMID:27092298

  16. Mechanistic Insights into the Role of C-Type Lectin Receptor/CARD9 Signaling in Human Antifungal Immunity

    PubMed Central

    Drummond, Rebecca A.; Lionakis, Michail S.

    2016-01-01

    Human CARD9 deficiency is an autosomal recessive primary immunodeficiency disorder caused by biallelic mutations in the gene CARD9, which encodes a signaling protein that is found downstream of many C-type lectin receptors (CLRs). CLRs encompass a large family of innate recognition receptors, expressed predominantly by myeloid and epithelial cells, which bind fungal carbohydrates and initiate antifungal immune responses. Accordingly, human CARD9 deficiency is associated with the spontaneous development of persistent and severe fungal infections that primarily localize to the skin and subcutaneous tissue, mucosal surfaces and/or central nervous system (CNS). In the last 3 years, more than 15 missense and nonsense CARD9 mutations have been reported which associate with the development of a wide spectrum of fungal infections caused by a variety of fungal organisms. The mechanisms by which CARD9 provides organ-specific protection against these fungal infections are now emerging. In this review, we summarize recent immunological and clinical advances that have provided significant mechanistic insights into the pathogenesis of human CARD9 deficiency. We also discuss how genetic mutations in CARD9-coupled receptors (Dectin-1, Dectin-2) and CARD9-binding partners (MALT1, BCL10) affect human antifungal immunity relative to CARD9 deficiency, and we highlight major understudied research questions which merit future investigation. PMID:27092298

  17. C-type lectin like receptor 2 (CLEC-2) signals independently of lipid raft microdomains in platelets.

    PubMed

    Manne, Bhanu Kanth; Badolia, Rachit; Dangelmaier, Carol A; Kunapuli, Satya P

    2015-01-15

    C-type lectin like receptor 2 (CLEC-2) has been reported to activate platelets through a lipid raft-dependent manner. Secreted ADP potentiates CLEC-2-mediated platelet aggregation. We have investigated whether the decrease in CLEC-2-mediated platelet aggregation, previously reported in platelets with disrupted rafts, is a result of the loss of agonist potentiation by ADP. We disrupted platelet lipid rafts with methyl-β-cyclodextrin (MβCD) and measured signaling events downstream of CLEC-2 activation. Lipid raft disruption decreases platelet aggregation induced by CLEC-2 agonists. The inhibition of platelet aggregation by the disruption of lipid rafts was rescued by the exogenous addition of epinephrine but not 2-methylthioadenosine diphosphate (2MeSADP), which suggests that lipid raft disruption effects P2Y12-mediated Gi activation but not Gz. Phosphorylation of Syk (Y525/526) and PLCγ2 (Y759), were not affected by raft disruption in CLEC-2 agonist-stimulated platelets. Furthermore, tyrosine phosphorylation of the CLEC-2 hemi-ITAM was not effected when MβCD disrupts lipid rafts. Lipid rafts do not directly contribute to CLEC-2 receptor activation in platelets. The effects of disruption of lipid rafts in in vitro assays can be attributed to inhibition of ADP feedback that potentiates CLEC-2 signaling.

  18. The C-Type Lectin Receptor MCL Mediates Vaccine-Induced Immunity against Infection with Blastomyces dermatitidis.

    PubMed

    Wang, Huafeng; Li, Mengyi; Lerksuthirat, Tassanee; Klein, Bruce; Wüthrich, Marcel

    2015-12-14

    C-type lectin receptors (CLRs) are essential in shaping the immune response to fungal pathogens. Vaccine-induced resistance requires Dectin-2 to promote differentiation of antifungal Th1 and Th17 cells. Since Dectin-2 and MCL heterodimerize and both CLRs use FcRγ as the signaling adaptor, we investigated the role of MCL in vaccine immunity to the fungal pathogen Blastomyces dermatitidis. MCL(-/-) mice showed impaired vaccine resistance against B. dermatitidis infection compared to that of wild-type animals. The lack of resistance correlated with the reduced recruitment of Th17 cells to the lung upon recall following experimental challenge and impaired interleukin-17 (IL-17) production by vaccine antigen-stimulated splenocytes in vitro. Soluble MCL fusion protein recognized and bound a water-soluble ligand from the cell wall of vaccine yeast, but the addition of soluble Dectin-2 fusion protein did not augment ligand recognition by MCL. Taken together, our data indicate that MCL regulates the development of vaccine-induced Th17 cells and protective immunity against lethal experimental infection with B. dermatitidis.

  19. The C-Type Lectin Receptor MCL Mediates Vaccine-Induced Immunity against Infection with Blastomyces dermatitidis

    PubMed Central

    Wang, Huafeng; Li, Mengyi; Lerksuthirat, Tassanee; Klein, Bruce

    2015-01-01

    C-type lectin receptors (CLRs) are essential in shaping the immune response to fungal pathogens. Vaccine-induced resistance requires Dectin-2 to promote differentiation of antifungal Th1 and Th17 cells. Since Dectin-2 and MCL heterodimerize and both CLRs use FcRγ as the signaling adaptor, we investigated the role of MCL in vaccine immunity to the fungal pathogen Blastomyces dermatitidis. MCL−/− mice showed impaired vaccine resistance against B. dermatitidis infection compared to that of wild-type animals. The lack of resistance correlated with the reduced recruitment of Th17 cells to the lung upon recall following experimental challenge and impaired interleukin-17 (IL-17) production by vaccine antigen-stimulated splenocytes in vitro. Soluble MCL fusion protein recognized and bound a water-soluble ligand from the cell wall of vaccine yeast, but the addition of soluble Dectin-2 fusion protein did not augment ligand recognition by MCL. Taken together, our data indicate that MCL regulates the development of vaccine-induced Th17 cells and protective immunity against lethal experimental infection with B. dermatitidis. PMID:26667836

  20. C-Type Lectin-Like Receptor LOX-1 Promotes Dendritic Cell-Mediated Class-Switched B Cell Responses

    PubMed Central

    Joo, HyeMee; Li, Dapeng; Dullaers, Melissa; Kim, Tae-Whan; Duluc, Dorothee; Upchurch, Katherine; Xue, Yaming; Zurawski, Sandy; Le Grand, Roger; Liu, Yong-Jun; Kuroda, Marcelo; Zurawski, Gerard; Oh, SangKon

    2014-01-01

    SUMMARY Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a pattern recognition receptor for a variety of endogenous and exogenous ligands. However, LOX-1 function in the host immune response is not fully understood. Here, we report that LOX-1 expressed on dendritic cells (DCs) and B cells promotes humoral responses. On B cells LOX-1 signaling upregulated CCR7, promoting cellular migration towards lymphoid tissues. LOX-1 signaling on DCs licensed the cells to promote B cell differentiation into class-switched plasmablasts, and led to downregulation of chemokine receptor CXCR5 and upregulation of chemokine receptor CCR10 on plasmablasts, which enabled their exit from germinal centers and migration towards local mucosa and skin. Finally, we found that targeting influenza hemagglutinin 1 (HA1) subunit to LOX-1 elicited HA1-specific protective antibody responses in rhesus macaques. Thus, LOX-1 expressed on B cells and DC cells has complementary functions to promote humoral immune responses. PMID:25308333

  1. C-type lectin receptors Dectin-3 and Dectin-2 form a heterodimeric pattern-recognition receptor for host defense against fungal infection.

    PubMed

    Zhu, Le-Le; Zhao, Xue-Qiang; Jiang, Changying; You, Yun; Chen, Xiao-Ping; Jiang, Yuan-Ying; Jia, Xin-Ming; Lin, Xin

    2013-08-22

    C-type lectin receptors (CLRs) play critical roles as pattern-recognition receptors (PRRs) for sensing Candida albicans infection, which can be life-threatening for immunocompromised individuals. Here we have shown that Dectin-3 (also called CLECSF8, MCL, or Clec4d), a previously uncharacterized CLR, recognized α-mannans on the surfaces of C. albicans hyphae and induced NF-κB activation. Mice with either blockade or genetically deleted Dectin-3 were highly susceptible to C. albicans infection. Dectin-3 constantly formed heterodimers with Dectin-2, a well-characterized CLR, for recognizing C. albicans hyphae. Compared to their respective homodimers, Dectin-3 and Dectin-2 heterodimers bound α-mannans more effectively, leading to potent inflammatory responses against fungal infections. Together, our study demonstrates that Dectin-3 forms a heterodimeric PRR with Dectin-2 for sensing fungal infection and suggests that different CLRs may form different hetero- and homodimers, which provide different sensitivity and diversity for host cells to detect various microbial infections.

  2. E3 ubiquitin ligase CHIP interacts with C-type lectin-like receptor CLEC-2 and promotes its ubiquitin-proteasome degradation.

    PubMed

    Shao, Miaomiao; Li, Lili; Song, Shushu; Wu, Weicheng; Peng, Peike; Yang, Caiting; Zhang, Mingming; Duan, Fangfang; Jia, Dongwei; Zhang, Jie; Wu, Hao; Zhao, Ran; Wang, Lan; Ruan, Yuanyuan; Gu, Jianxin

    2016-10-01

    C-type lectin-like receptor 2 (CLEC-2) was originally identified as a member of non-classical C-type lectin-like receptors in platelets and immune cells. Activation of CLEC-2 is involved in thrombus formation, lymphatic/blood vessel separation, platelet-mediated tumor metastasis and immune response. Nevertheless, the regulation of CLEC-2 expression is little understood. In this study, we identified that the C terminus of Hsc70-interacting protein (CHIP) interacted with CLEC-2 by mass spectrometry analysis, and CHIP decreased the protein expression of CLEC-2 through lysine-48-linked ubiquitination and proteasomal degradation. Deleted and point mutation also revealed that CHIP controlled CLEC-2 protein expression via both tetratricopeptide repeats (TPR) domain and Ubox domain in a HSP70/90-independent manner. Moreover, reduced CHIP expression was associated with decreased CLEC-2 polyubiquitination and increased CLEC-2 protein levels in PMA-induced differentiation of THP-1 monocytes into macrophages. These results indicate that CLEC-2 is the target substrate of E3 ubiquitin ligase CHIP, and suggest that the CHIP/CLEC-2 axis may play an important role in the modulation of immune response.

  3. C-type lectin-like domain and fibronectin-like type II domain of phospholipase A(2) receptor 1 modulate binding and migratory responses to collagen.

    PubMed

    Takahashi, Soichiro; Watanabe, Kazuhiro; Watanabe, Yosuke; Fujioka, Daisuke; Nakamura, Takamitsu; Nakamura, Kazuto; Obata, Jun-ei; Kugiyama, Kiyotaka

    2015-03-24

    Phospholipase A2 receptor 1 (PLA2R) mediates collagen-dependent migration. The mechanisms by which PLA2R interacts with collagen remain unclear. We produced HEK293 cells expressing full-length wild-type PLA2R or a truncated PLA2R that lacks fibronectin-like type II (FNII) domains or several regions of C-type lectin-like domain (CTLD). We show that the CTLD1-2 as well as the FNII domain of PLA2R are responsible for binding to collagen and for collagen-dependent migration. Thus, multiple regions and domains of the extracellular portion of PLA2R participate in the responses to collagen. These data suggest a potentially new mechanism for PLA2R-mediated biological response beyond that of a receptor for secretory PLA2.

  4. Structure of the complex of F-actin and DNGR-1, a C-type lectin receptor involved in dendritic cell crosspresentation of dead cell-associated antigens

    PubMed Central

    Iborra, Salvador; Yamada, Yurika; Huotari, Jatta; Schulz, Oliver; Ahrens, Susan; Kjær, Svend; Way, Michael; Sancho, David; Namba, Keiichi; Reis e Sousa, Caetano

    2016-01-01

    Summary DNGR-1 is a C-type lectin receptor that binds F-actin exposed by dying cells and facilitates cross-presentation of dead cell-associated antigens by dendritic cells. Here we present the structure of DNGR-1 bound to F-actin at 7.7 Å resolution. Unusually for F-actin binding proteins, the DNGR-1 ligand binding domain contacts three actin subunits helically arranged in the actin filament, bridging over two protofilaments, as well as two neighboring actin subunits along one protofilament. Mutation of residues predicted to mediate ligand binding led to loss of DNGR-1-dependent cross-presentation of dead cell-associated antigens, formally demonstrating that the latter depends on F-actin recognition. Notably, DNGR-1 has relatively modest affinity for F-actin but multivalent interactions allow a marked increase in binding strength. Our findings shed light on modes of actin binding by cellular proteins and reveal how extracellular detection of cytoskeletal components by dedicated receptors allows immune monitoring of loss of cellular integrity. PMID:25979418

  5. A platform to screen for C-type lectin receptor-binding carbohydrates and their potential for cell-specific targeting and immune modulation.

    PubMed

    Maglinao, Maha; Eriksson, Magdalena; Schlegel, Mark K; Zimmermann, Stephanie; Johannssen, Timo; Götze, Sebastian; Seeberger, Peter H; Lepenies, Bernd

    2014-02-10

    Myeloid C-type lectin receptors (CLRs) in innate immunity represent a superfamily of pattern recognition receptors that recognize carbohydrate structures on pathogens and self-antigens. The primary interaction of an antigen-presenting cell and a pathogen shapes the following immune response. Therefore, the identification of CLR ligands that can either enhance or modulate the immune response is of interest. We have developed a screening platform based on glycan arrays to identify immune modulatory carbohydrate ligands of CLRs. A comprehensive library of CLRs was expressed by fusing the extracellular part of each respective CLR, the part containing the carbohydrate-recognition domain (CRD), to the Fc fragment of human IgG1 molecules. CLR-Fc fusion proteins display the CRD in a dimeric form, are properly glycosylated, and can be detected by a secondary antibody with a conjugated fluorophore. Thus, they are valuable tools for high-throughput screening. We were able to identify novel carbohydrate binders of CLRs using the glycan array technology. These CLR-binding carbohydrates were then covalently attached to the model antigen ovalbumin. The ovalbumin neoglycoconjugates were used in a dendritic cell/T cell co-culture assay to stimulate transgenic T cells in vitro. In addition, mice were immunized with these conjugates to analyze the immune modulatory properties of the CLR ligands in vivo. The CLR ligands induced an increased Th1 cytokine production in vitro and modulated the humoral response in vivo. The platform described here allows for the identification of CLR ligands, as well as the evaluation of each ligand's cell-specific targeting and immune modulatory properties.

  6. Structural analysis for glycolipid recognition by the C-type lectins Mincle and MCL

    PubMed Central

    Furukawa, Atsushi; Kamishikiryo, Jun; Mori, Daiki; Toyonaga, Kenji; Okabe, Yuki; Toji, Aya; Kanda, Ryo; Miyake, Yasunobu; Ose, Toyoyuki; Yamasaki, Sho; Maenaka, Katsumi

    2013-01-01

    Mincle [macrophage inducible Ca2+-dependent (C-type) lectin; CLEC4E] and MCL (macrophage C-type lectin; CLEC4D) are receptors for the cord factor TDM (trehalose-6,6′-dimycolate), a unique glycolipid of mycobacterial cell-surface components, and activate immune cells to confer adjuvant activity. Although it is known that receptor–TDM interactions require both sugar and lipid moieties of TDM, the mechanisms of glycolipid recognition by Mincle and MCL remain unclear. We here report the crystal structures of Mincle, MCL, and the Mincle–citric acid complex. The structures revealed that these receptors are capable of interacting with sugar in a Ca2+-dependent manner, as observed in other C-type lectins. However, Mincle and MCL uniquely possess shallow hydrophobic regions found adjacent to their putative sugar binding sites, which reasonably locate for recognition of fatty acid moieties of glycolipids. Functional studies using mutant receptors as well as glycolipid ligands support this deduced binding mode. These results give insight into the molecular mechanism of glycolipid recognition through C-type lectin receptors, which may provide clues to rational design for effective adjuvants. PMID:24101491

  7. Transmission-blocking antibodies against mosquito C-type lectins for dengue prevention.

    PubMed

    Liu, Yang; Zhang, Fuchun; Liu, Jianying; Xiao, Xiaoping; Zhang, Siyin; Qin, Chengfeng; Xiang, Ye; Wang, Penghua; Cheng, Gong

    2014-02-01

    C-type lectins are a family of proteins with carbohydrate-binding activity. Several C-type lectins in mammals or arthropods are employed as receptors or attachment factors to facilitate flavivirus invasion. We previously identified a C-type lectin in Aedes aegypti, designated as mosquito galactose specific C-type lectin-1 (mosGCTL-1), facilitating the attachment of West Nile virus (WNV) on the cell membrane. Here, we first identified that 9 A. aegypti mosGCTL genes were key susceptibility factors facilitating DENV-2 infection, of which mosGCTL-3 exhibited the most significant effect. We found that mosGCTL-3 was induced in mosquito tissues with DENV-2 infection, and that the protein interacted with DENV-2 surface envelop (E) protein and virions in vitro and in vivo. In addition, the other identified mosGCTLs interacted with the DENV-2 E protein, indicating that DENV may employ multiple mosGCTLs as ligands to promote the infection of vectors. The vectorial susceptibility factors that facilitate pathogen invasion may potentially be explored as a target to disrupt the acquisition of microbes from the vertebrate host. Indeed, membrane blood feeding of antisera against mosGCTLs dramatically reduced mosquito infective ratio. Hence, the immunization against mosGCTLs is a feasible approach for preventing dengue infection. Our study provides a future avenue for developing a transmission-blocking vaccine that interrupts the life cycle of dengue virus and reduces disease burden. PMID:24550728

  8. Two antibacterial C-type lectins from crustacean, Eriocheir sinensis, stimulated cellular encapsulation in vitro.

    PubMed

    Jin, Xing-Kun; Li, Shuang; Guo, Xiao-Nv; Cheng, Lin; Wu, Min-Hao; Tan, Shang-Jian; Zhu, You-Ting; Yu, Ai-Qing; Li, Wei-Wei; Wang, Qun

    2013-12-01

    The first step of host fighting against pathogens is that pattern recognition receptors recognized pathogen-associated molecular patterns. However, the specificity of recognition within the innate immune molecular of invertebrates remains largely unknown. In the present study, we investigated how invertebrate pattern recognition receptor (PRR) C-type lectins might be involved in the antimicrobial response in crustacean. Based on our previously obtained completed coding regions of EsLecA and EsLecG in Eriocheir sinensis, the recombinant EsLectin proteins were produced via prokaryotic expression system and affinity chromatography. Subsequently, both rEsLecA and rEsLecG were discovered to have wide spectrum binding activities towards microorganisms, and their microbial-binding was calcium-independent. Moreover, the binding activities of both rEsLecA and rEsLecG induced the aggregation against microbial pathogens. Both microorganism growth inhibitory activities assays and antibacterial activities assays revealed their capabilities of suppressing microorganisms growth and directly killing microorganisms respectively. Furthermore, the encapsulation assays signified that both rEsLecA and rEsLecG could stimulate the cellular encapsulation in vitro. Collectively, data presented here demonstrated the successful expression and purification of two C-type lectins proteins in the Chinese mitten crab, and their critical role in the innate immune system of an invertebrate.

  9. Mosquito C-type lectins maintain gut microbiome homeostasis.

    PubMed

    Pang, Xiaojing; Xiao, Xiaoping; Liu, Yang; Zhang, Rudian; Liu, Jianying; Liu, Qiyong; Wang, Penghua; Cheng, Gong

    2016-01-01

    The long-term evolutionary interaction between the host immune system and symbiotic bacteria determines their cooperative rather than antagonistic relationship. It is known that commensal bacteria have evolved a number of mechanisms to manipulate the mammalian host immune system and maintain homeostasis. However, the strategies employed by the microbiome to overcome host immune responses in invertebrates still remain to be understood. Here, we report that the gut microbiome in mosquitoes utilizes C-type lectins (mosGCTLs) to evade the bactericidal capacity of antimicrobial peptides (AMPs). Aedes aegypti mosGCTLs facilitate colonization by multiple bacterial strains. Furthermore, maintenance of the gut microbial flora relies on the expression of mosGCTLs in A. aegypti. Silencing the orthologues of mosGCTL in another major mosquito vector (Culex pipiens pallens) also impairs the survival of gut commensal bacteria. The gut microbiome stimulates the expression of mosGCTLs, which coat the bacterial surface and counteract AMP activity. Our study describes a mechanism by which the insect symbiotic microbiome offsets gut immunity to achieve homeostasis. PMID:27572642

  10. Mosquito C-type lectins maintain gut microbiome homeostasis

    PubMed Central

    Pang, Xiaojing; Xiao, Xiaoping; Liu, Yang; Zhang, Rudian; Liu, Jianying; Liu, Qiyong; Wang, Penghua; Cheng, Gong

    2016-01-01

    The long-term evolutionary interaction between the host immune system and symbiotic bacteria determines their cooperative rather than antagonistic relationship. It is known that commensal bacteria have evolved a number of mechanisms to manipulate the mammalian host immune system and maintain homeostasis. However, the strategies employed by the microbiome to overcome host immune responses in invertebrates still remain to be understood. Here, we report that the gut microbiome in mosquitoes utilizes C-type lectins (mosGCTLs) to evade the bactericidal capacity of antimicrobial peptides (AMPs). Aedes aegypti mosGCTLs facilitate colonization by multiple bacterial strains. Furthermore, maintenance of the gut microbial flora relies on the expression of mosGCTLs in A. aegypti. Silencing the orthologues of mosGCTL in another major mosquito vector (Culex pipiens pallens) also impairs the survival of gut commensal bacteria. The gut microbiome stimulates the expression of mosGCTLs, which coat the bacterial surface and counteract AMP activity. Our study describes a mechanism by which the insect symbiotic microbiome offsets gut immunity to achieve homeostasis. PMID:27170846

  11. The Dectin-2 family of C-type lectins in immunity and homeostasis

    PubMed Central

    Graham, Lisa M.; Brown, Gordon D.

    2009-01-01

    C-type lectins are a diverse family of proteins which recognize a wide range of ligands. This review focuses on the Dectin-2 family of C-type lectins that includes Dectin-2, BDCA-2, DCIR, DCAR, Clecsf8 and Mincle whose genes are clustered in the telomeric region of the NK-gene cluster on mouse chromosome 6 and human chromosome 12. These type II receptors are expressed on myeloid and non-myeloid cells and contain a single extracellular carbohydrate recognition domain and have diverse functions in both immunity and homeostasis. DCIR is the only member of the family which contains a cytoplasmic signalling motif and has been shown to act as an inhibitory receptor, while BDCA-2, Dectin-2, DCAR and Mincle all associate with FcRγ chain to induce cellular activation, including phagocytosis and cytokine production. Dectin-2 and Mincle have been shown to act as pattern recognition receptors for fungi, while DCIR acts as an attachment factor for HIV. In addition to pathogen recognition, DCIR has been shown to be pivotal in preventing autoimmune disease by controlling dendritic cell proliferation, whereas Mincle recognizes a nuclear protein released by necrotic cells. Here we review each of these receptors in detail describing their expression, ligand recognition, signalling and known physiological functions. PMID:19665392

  12. Structural and biological characterization of Nattectin, a new C-type lectin from the venomous fish Thalassophryne nattereri.

    PubMed

    Lopes-Ferreira, Mônica; Magalhães, Geraldo Santana; Fernandez, Jorge Hernandez; Junqueira-de-Azevedo, Inácio de Loiola M; Le Ho, Paulo; Lima, Carla; Valente, Richard H; Moura-da-Silva, Ana Maria

    2011-06-01

    Lectins are glycan-binding receptors that recognize glycan epitopes on foreign pathogens and in the host systems. They can be involved in functions that include innate immunity, development, immune regulation and homeostasis. Several lectins have been purified and characterized from fish species. In this work, using cation-exchange chromatography, a galactose-specific lectin belonging to the family of C-type lectins was isolated from the venom of the Brazilian venomous fish Thalassophryne nattereri. Nattectin is a basic, non-glycosilated, 15 kDa monomeric protein. It exhibits hemagglutination activity that is independent of Ca(2+). We also demonstrated a lectin activity for Nattectin in the innate immune system, especially in neutrophil mobilization in mice, indicating that marine organisms are source of immunomodulator agents.

  13. Molecular cloning and characterization of a C-type lectin in yellow catfish Tachysurus fulvidraco.

    PubMed

    Ke, F; Zhang, H B; Wang, Y; Hou, L F; Dong, H J; Wang, Z F; Pan, G W; Cao, X Y

    2016-09-01

    This study represents the first report of a C-type lectin (ctl) in yellow catfish Tachysurus fulvidraco. The complete sequence of ctl complementary (c)DNA consisted of 685 nucleotides. The open reading frame potentially encoded a protein of 177 amino acids with a calculated molecular mass of c.y 20.204 kDa. The deduced amino-acid sequence contained a signal peptide and a single carbohydrate recognition domain with four cysteine residues and GlnProAsp (QPD) and TrpAsnAsp (WND) motifs. Ctl showed the highest identity (56.0%) to the predicted lactose binding lectin from channel catfish Ictalurus punctatus. Quantitative real-time (qrt)-PCR analysis showed that ctl messenger (m)RNA was constitutively expressed in all examined tissues in normal fish, with high expression in trunk kidney and head kidney, which was increased following Aeromonas hydrophila challenge in a duration-dependent manner. Purified recombinant Ctl (rCtl) from Escherichia coli BL21 was able to bind and agglutinate Gram-positive and Gram-negative bacteria in a calcium-dependent manner. These results suggested that Ctl might be a C-type lectin of T. fulvidraco involved in innate immune responses as receptors (PRR). PMID:27418461

  14. Recombinant expression, in vitro refolding and characterizing disulfide bonds of a mouse inhibitory C-type lectin-like receptor Nkrp1b.

    PubMed

    Hernychová, L; Mrázek, H; Ivanova, L; Kukačka, Z; Chmelík, J; Novák, P

    2015-01-01

    As a part of the innate immunity, NK (Natural Killer) cells provide an early immune response to different stimuli, e.g. viral infections and tumor growths. However, their functions are more complex; they play an important role in reproduction, alloimmunity, autoimmunity and allergic diseases. NK cell activities require an intricate system of regulation that is ensured by many different receptors on a cell surface which integrate signals from interacting cells and soluble factors. One way to understand NK cell biology is through the structure of NK receptors, which can reveal ligand binding conditions. We present a modified protocol for recombinant expression in Escherichia coli and in vitro refolding of the ligand-binding domain of the inhibitory Nkrp1b (SJL/J) protein. Nkrp1b identity and folding was confirmed using mass spectrometry (accurate mass of the intact protein and evaluation of disulfide bonds) and one-dimensional nuclear magnetic resonance spectroscopy. The intention is to provide the basis for conducting structural studies of the inhibitory Nkrp1b protein, since only the activating Nkrp1a receptor structure is known. PMID:26447598

  15. The Snake Venom Rhodocytin from Calloselasma rhodostoma—A Clinically Important Toxin and a Useful Experimental Tool for Studies of C-Type Lectin-Like Receptor 2 (CLEC-2)

    PubMed Central

    Bruserud, Øyvind

    2013-01-01

    The snake venom, rhodocytin, from the Malayan viper, Calloselasma rhodostoma, and the endogenous podoplanin are identified as ligands for the C-type lectin-like receptor 2 (CLEC-2). The snakebites caused by Calloselasma rhodostoma cause a local reaction with swelling, bleeding and eventually necrosis, together with a systemic effect on blood coagulation with distant bleedings that can occur in many different organs. This clinical picture suggests that toxins in the venom have effects on endothelial cells and vessel permeability, extravasation and, possibly, activation of immunocompetent cells, as well as effects on platelets and the coagulation cascade. Based on the available biological studies, it seems likely that ligation of CLEC-2 contributes to local extravasation, inflammation and, possibly, local necrosis, due to microthrombi and ischemia, whereas other toxins may be more important for the distant hemorrhagic complications. However, the venom contains several toxins and both local, as well as distant, symptoms are probably complex reactions that cannot be explained by the effects of rhodocytin and CLEC-2 alone. The in vivo reactions to rhodocytin are thus examples of toxin-induced crosstalk between coagulation (platelets), endothelium and inflammation (immunocompetent cells). Very few studies have addressed this crosstalk as a part of the pathogenesis behind local and systemic reactions to Calloselasma rhodostoma bites. The author suggests that detailed biological studies based on an up-to-date methodology of local and systemic reactions to Calloselasma rhodostoma bites should be used as a hypothesis-generating basis for future functional studies of the CLEC-2 receptor. It will not be possible to study the effects of purified toxins in humans, but the development of animal models (e.g., cutaneous injections of rhodocytin to mimic snakebites) would supplement studies in humans. PMID:23594438

  16. The snake venom rhodocytin from Calloselasma rhodostoma- a clinically important toxin and a useful experimental tool for studies of C-type lectin-like receptor 2 (CLEC-2).

    PubMed

    Bruserud, Øyvind

    2013-04-17

    The snake venom, rhodocytin, from the Malayan viper, Calloselasma rhodostoma, and the endogenous podoplanin are identified as ligands for the C-type lectin-like receptor 2 (CLEC-2). The snakebites caused by Calloselasma rhodostoma cause a local reaction with swelling, bleeding and eventually necrosis, together with a systemic effect on blood coagulation with distant bleedings that can occur in many different organs. This clinical picture suggests that toxins in the venom have effects on endothelial cells and vessel permeability, extravasation and, possibly, activation of immunocompetent cells, as well as effects on platelets and the coagulation cascade. Based on the available biological studies, it seems likely that ligation of CLEC-2 contributes to local extravasation, inflammation and, possibly, local necrosis, due to microthrombi and ischemia, whereas other toxins may be more important for the distant hemorrhagic complications. However, the venom contains several toxins and both local, as well as distant, symptoms are probably complex reactions that cannot be explained by the effects of rhodocytin and CLEC-2 alone. The in vivo reactions to rhodocytin are thus examples of toxin-induced crosstalk between coagulation (platelets), endothelium and inflammation (immunocompetent cells). Very few studies have addressed this crosstalk as a part of the pathogenesis behind local and systemic reactions to Calloselasma rhodostoma bites. The author suggests that detailed biological studies based on an up-to-date methodology of local and systemic reactions to Calloselasma rhodostoma bites should be used as a hypothesis-generating basis for future functional studies of the CLEC-2 receptor. It will not be possible to study the effects of purified toxins in humans, but the development of animal models (e.g., cutaneous injections of rhodocytin to mimic snakebites) would supplement studies in humans.

  17. A C-type lectin is involved in the innate immune response of Chinese white shrimp.

    PubMed

    Wang, Xian-Wei; Xu, Wen-Teng; Zhang, Xiao-Wen; Zhao, Xiao-Fan; Yu, Xiao-Qiang; Wang, Jin-Xing

    2009-10-01

    C-type lectins may function as pattern-recognition receptors (PRRs) and play important roles in immune responses. In this work, a cDNA for a new C-type lectin, FcLec3, was obtained from Chinese white shrimp Fenneropenaeus chinensis using expressed sequence tag analysis and rapid amplification of the cDNA ends. FcLec3 contains an N-terminal signal peptide and a carbohydrate recognition domain (CRD). RT-PCR analysis showed that FcLec3 was mainly expressed in hepatopancreas and that the expression of FcLec3 was obviously up-regulated by Vibrio anguillarum or white spot syndrome virus (WSSV) challenge. Recombinant FcLec3 could agglutinate Gram-negative and -positive bacteria with the presence of calcium. A following agglutination inhibitory test indicated that FcLec3 could recognize muramic acid and peptidoglycan. Besides, pull-down assay showed that the recombinant protein could interact with VP28, one major envelope protein of WSSV. These results suggested that FcLec3 might function in the recognition of bacterial and viral pathogens in shrimp. PMID:19647083

  18. Differential Use of the C-Type Lectins L-SIGN and DC-SIGN for Phlebovirus Endocytosis.

    PubMed

    Léger, Psylvia; Tetard, Marilou; Youness, Berthe; Cordes, Nicole; Rouxel, Ronan N; Flamand, Marie; Lozach, Pierre-Yves

    2016-06-01

    Bunyaviruses represent a growing threat to humans and livestock globally. The receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely unidentified and poorly characterized. DC-SIGN is a C-type lectin highly expressed on dermal dendritic cells that has been found to act as an authentic entry receptor for many phleboviruses (Bunyaviridae), including Rift Valley fever virus (RVFV), Toscana virus (TOSV) and Uukuniemi virus (UUKV). We found that these phleboviruses can exploit another C-type lectin, L-SIGN, for infection. L-SIGN shares 77% sequence homology with DC-SIGN and is expressed on liver sinusoidal endothelial cells. L-SIGN is required for UUKV binding but not for virus internalization. An endocytosis-defective mutant of L-SIGN was still able to mediate virus uptake and infection, indicating that L-SIGN acts as an attachment receptor for phleboviruses rather than an endocytic receptor. Our results point out a fundamental difference in the use of the C-type lectins L-SIGN and DC-SIGN by UUKV to enter cells, although both proteins are closely related in terms of molecular structure and biological function. This study sheds new light on the molecular mechanisms by which phleboviruses target the liver and also highlights the added complexity in virus-receptor interactions beyond attachment. PMID:26990254

  19. Critical roles of sea cucumber C-type lectin in non-self recognition and bacterial clearance.

    PubMed

    Wei, Xiumei; Liu, Xiangquan; Yang, Jianmin; Wang, Sheng; Sun, Guohua; Yang, Jialong

    2015-08-01

    C-type lectin is one important pattern recognition receptor (PRR) that plays crucial roles in multiple immune responses. A C-type lectin from sea cucumber Apostichopus japonicus (AjCTL-1) was characterized in the present study. The amino acid sequence of AjCTL-1 shared high similarities with other C-type lectins from invertebrates and vertebrates. The C-type lectin domain (CTLD) of AjCTL-1 contained a Ca(2+)-binding site 2 and four conserved cysteine residues. AjCTL-1 mRNA expression patterns in tissues and after bacterial challenge were then analysed. Quantitative PCR revealed that AjCTL-1 mRNA was widely expressed in the tested tissues of healthy sea cucumber. The highest expression level occurred in gonad followed by body wall, coelomocytes, tentacle, intestinum and longitudinal muscle, and the lowest expression level was in respiratory tree. AjCTL-1 mRNA expression in coelomocytes was significantly induced by gram-negative Listonella anguillarum and gram-positive Micrococcus luteus, with different up-regulation patterns post-challenge. Recombinant AjCTL-1 exhibited the ability to bind peptidoglycan directly, agglutinate M. luteus, Staphylococcus aureus and Escherichia coli, in a Ca(2+)-dependant manner, and enhance the phagocytosis of coelomocytes against E. coli in vitro. The results indicated that AjCTL-1 could act as a PRR in Apostichopus japonicus and had critical roles in non-self recognition and bacterial clearance against invading microbes.

  20. Participation of a galactose-specific C-type lectin in Drosophila immunity

    PubMed Central

    Tanji, Takahiro; Ohashi-Kobayashi, Ayako; Natori, Shunji

    2006-01-01

    A galactose-specific C-type lectin has been purified from a pupal extract of Drosophila melanogaster. This lectin gene, named DL1 (Drosophila lectin 1), is part of a gene cluster with the other two galactose-specific C-type lectin genes, named DL2 (Drosophila lectin 2) and DL3 (Drosophila lectin 3). These three genes are expressed differentially in fruit fly, but show similar haemagglutinating activities. The present study characterized the biochemical and biological properties of the DL1 protein. The recombinant DL1 protein bound to Escherichia coli and Erwinia chrysanthemi, but not to other Gram-negative or any other kinds of microbial strains that have been investigated. In addition, DL1 agglutinated E. coli and markedly intensified the association of a Drosophila haemocytes-derived cell line with E. coli. For in vivo genetic analysis of the lectin genes, we also established a null-mutant Drosophila. The induction of inducible antibacterial peptide genes was not impaired in the DL1 mutant, suggesting that the galactose-specific C-type lectin does not participate in the induction of antibacterial peptides, but possibly participates in the immune response via the haemocyte-mediated mechanism. PMID:16475980

  1. Lectins in the investigation of receptors

    NASA Astrophysics Data System (ADS)

    Lakhtin, V. M.; Yamskov, Igor A.

    1991-08-01

    Problems of the purification and characterisation are considered for approximately 270 receptors (including cell surface and organelle enzymes), which are glycoconjugates (mainly glycoproteins) from animals, plants and microorganisms, using various lectins (mainly lectin sorbents). An analysis has been carried out of the stages of lectin affinity chromatography of receptors (choice of detergent, use of organic solvents, elution with carbohydrates, etc.). Examples are given of procedures for the purification of receptors, including the use of paired columns and combination chromatography on lectins. The possibility of separating sub-populations of receptors using lectins has been demonstrated. Examples are given of the use of lectins in the analysis of the oligosaccharide structure of receptors. Cases are recorded of the interaction of receptors with endogenous lectins and of receptor lectins with endogenous glycoconjugates. It has been shown that lectins, in combination with glycosidases and antibodies, may be useful in the investigation of receptors. The bibliography contains 406 references.

  2. C-type lectin from red swamp crayfish Procambarus clarkii participates in cellular immune response.

    PubMed

    Zhang, Xiao-Wen; Wang, Xian-Wei; Sun, Chen; Zhao, Xiao-Fan; Wang, Jin-Xing

    2011-03-01

    Lectins are potential immune recognition proteins. In this study, a novel C-type lectin (Pc-Lec1) is reported in freshwater crayfish Procambarus clarkii. Pc-Lec1 encodes a protein of 163 amino acids with a putative signal peptide and a single carbohydrate recognition domain. It was constitutively expressed in various tissues of a normal crayfish, especially in the hepatopancreas and gills. Expressions of Pc-Lec1 were up-regulated in the hepatopancreas and gills of crayfish challenged with Vibrio anguillarum, Staphylococcus aureus, or the white spot syndrome virus. Recombinant mature Pc-Lec1 bound bacteria and polysaccharides (peptidoglycan, lipoteichoic acid, and lipopolysaccharide) but did not agglutinate bacteria. Pc-Lec1 enhanced hemocyte encapsulation of the sepharose beads in vitro, and the blocking of beads by a polyclonal antibody inhibited encapsulation. Pc-Lec1 promoted clearance of V. anguillarum in vivo. These results suggest that Pc-Lec1 is a pattern recognition receptor and participates in cellular immune response. Pc-Lec1 performs its function as an opsonin by enhancing the encapsulation or clearance of pathogenic bacteria.

  3. A C-type lectin from Bothrops jararacussu venom disrupts Staphylococcal biofilms.

    PubMed

    Klein, Raphael Contelli; Fabres-Klein, Mary Hellen; de Oliveira, Leandro Licursi; Feio, Renato Neves; Malouin, François; Ribon, Andréa de Oliveira Barros

    2015-01-01

    Bovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S. aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S. aureus. Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16) showed the best activities and were also assayed against S. epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S. aureus and S. epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S. epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S. aureus, S. hyicus, S. chromogenes, Streptococcus agalactiae, and Escherichia coli. These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model.

  4. A C-Type Lectin from Bothrops jararacussu Venom Disrupts Staphylococcal Biofilms

    PubMed Central

    Klein, Raphael Contelli; Fabres-Klein, Mary Hellen; de Oliveira, Leandro Licursi; Feio, Renato Neves; Malouin, François; Ribon, Andréa de Oliveira Barros

    2015-01-01

    Bovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S. aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S. aureus. Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16) showed the best activities and were also assayed against S. epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S. aureus and S. epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S. epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S. aureus, S. hyicus, S. chromogenes, Streptococcus agalactiae, and Escherichia coli. These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model. PMID:25811661

  5. A C-type lectin from Bothrops jararacussu venom disrupts Staphylococcal biofilms.

    PubMed

    Klein, Raphael Contelli; Fabres-Klein, Mary Hellen; de Oliveira, Leandro Licursi; Feio, Renato Neves; Malouin, François; Ribon, Andréa de Oliveira Barros

    2015-01-01

    Bovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S. aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S. aureus. Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16) showed the best activities and were also assayed against S. epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S. aureus and S. epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S. epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S. aureus, S. hyicus, S. chromogenes, Streptococcus agalactiae, and Escherichia coli. These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model. PMID:25811661

  6. A four-CRD C-type lectin from Chlamys farreri mediating nonself-recognition with broader spectrum and opsonization.

    PubMed

    Huang, Mengmeng; Wang, Lingling; Yang, Jialong; Zhang, Huan; Wang, Leilei; Song, Linsheng

    2013-04-01

    C-type lectins are a superfamily of Ca(2+)-dependent carbohydrate-recognition proteins consisting of at least one carbohydrate-recognition domain (CRD), which participate in nonself-recognition and clearance of invaders. In invertebrate, some multidomain C-type lectins have been identified, but their relative functions and binding mechanism are still meager. In the present study, A C-type lectin (CfLec-4) with four CRDs from Chlamys farreri was selected to investigate its possible function in innate immunity. The mRNA expression of CfLec-4 in hemocytes was significantly up-regulated (P<0.01) after the stimulations of β-glucan, LPS or PGN, and reached the highest expression level at 3, 6, 12 h post-stimulation, which was 27.9-, 22.6- or 47.9-fold of that in blank group, respectively. Immunohistochemistry assay with polyclonal antibody specific for CfLec-4 revealed that the endogenous CfLec-4 was mainly located in the hepatopancreas, kidney and gonad of the scallops. The recombinant CfLec-4 (rCflec-4) could bind LPS, PGN, glucan and mannose in vitro, but could not bind LTA. Furthermore, rCflec-4 displayed a broader bacteria binding spectrum towards Gram-positive bacteria Staphylococcus aureus and Micrococcus luteus as well as Gram-negative bacteria Escherichia coli, Vibrio anguillarum and fungi Pichia pastoris. Meanwhile, rCfLec-4 could significantly (P<0.01) enhance the phagocytosis of hemocytes in vitro. The results clearly suggested that four-CRD containing CfLec-4 not only served as PRR with wider recognition spectrum, but also functioned as an opsonin participating in the clearance of invaders in scallops. It could be inferred that the diversity and complexity of CRDs in C-type lectins endowed these receptors with comprehensive recognition spectrum and multiple immune functions against complex living environment. PMID:23276881

  7. Identification of a C-type lectin from the bay scallop Argopecten irradians.

    PubMed

    Zhu, Ling; Song, Linsheng; Xu, Wei; Qian, Pei-Yuan

    2009-05-01

    C-type lectins are Ca(2+) dependent carbohydrate-recognition proteins that play crucial roles in the invertebrate innate immunity, such as nonself recognition, activation of proPO system, antibacterial activity, promotion of phagocytosis and nodule formation. In this study, a novel C-type lectin of bay scallops Argopecten irradians (Ai Lec) was identified using expressed sequence tag (EST) and RACE techniques. The Ai Lec cDNA encoded a polypeptide of 171 amino acids with a putative signal peptide of 21 amino acid residues and a mature protein of 150 amino acids. The deduced amino acid sequence of Ai Lec was highly similar to those of the C-type lectins from other animals and contained a typical carbohydrate-recognition domain (CRD) of 131 residues, which has four conserved disulfide-bonded cysteine residues that define the CRD and two additional cysteine residues at the amino terminus. The expression of Ai Lec transcript was dominantly detected in the hepatopancreas and slightly detected in the haemocytes of normal scallops. 6 h after Vibrio anguillarum-challenge and 8 h after Micrococcus luteus-challenge, the temporal expression of Ai Lec mRNA in hemocytes was increased by 4.4- and 3.6-folds, respectively. The results suggested that Ai Lec was a constitutive and inducible acute-phase protein and might be involved in immune response to Gram-negative and Gram-positive microbial infection in bay scallop A. irradians.

  8. Functions of Armigeres subalbatus C-type lectins in innate immunity

    PubMed Central

    Shi, Xiu-Zhen; Kang, Cui-Jie; Wang, Song-Jie; Zhong, Xue; Beerntsen, Brenda T.; Yu, Xiao-Qiang

    2014-01-01

    C-type lectins (CTLs) are a superfamily of calcium-dependent carbohydrate binding proteins containing at least one carbohydrate-recognition domain (CRD) and they are present in almost all metazoans. Insect CTLs may function as pattern-recognition receptors and play important roles in innate immunity. In this study, we selected five AsCTLs from the mosquito Armigeres subalbatus, a natural vector of filarial nematodes, and performed both in vitro and in vivo studies to elucidate their functions in innate immunity. AsCTLMA15, AsCTLGA5 and AsCTL15 were mainly expressed in hemocytes, AsCTL16 was expressed in fat body, while AsCTLMA11 was expressed in both hemocytes and fat body, and only AsCTLMA11 and AsCTL16 were expressed at high levels in adult females. In vitro binding assays showed that all five recombinant AsCTLs could bind to different microbial cell wall components, including lipopolysaccharide (LPS), lipid A, peptidoglycan (PG), lipoteichoic acid (LTA), zymosan and laminarin (beta-1,3-glucan). Recombinant AsCTLs also bound to several Gram-negative and Gram-positive bacteria, and could agglutinate bacterial cells. Injection of double-stranded RNAs (dsRNAs) could significantly reduce expression of the five AsCTL mRNAs, and the survival of mosquitoes treated with dsRNA to AsCTLGA5 was significantly decreased after Escherichia coli infection, but did not change significantly after Micrococcus luteus infection compared to the control groups, suggesting that Ar. subalbatus AsCTLGA5 may participate in innate immunity against E. coli. PMID:25014898

  9. Functions of Armigeres subalbatus C-type lectins in innate immunity.

    PubMed

    Shi, Xiu-Zhen; Kang, Cui-Jie; Wang, Song-Jie; Zhong, Xue; Beerntsen, Brenda T; Yu, Xiao-Qiang

    2014-09-01

    C-type lectins (CTLs) are a superfamily of calcium-dependent carbohydrate binding proteins containing at least one carbohydrate-recognition domain (CRD) and they are present in almost all metazoans. Insect CTLs may function as pattern-recognition receptors and play important roles in innate immunity. In this study, we selected five AsCTLs from the mosquito Armigeres subalbatus, a natural vector of filarial nematodes, and performed both in vitro and in vivo studies to elucidate their functions in innate immunity. AsCTLMA15, AsCTLGA5 and AsCTL15 were mainly expressed in hemocytes, AsCTL16 was expressed in fat body, while AsCTLMA11 was expressed in both hemocytes and fat body, and only AsCTLMA11 and AsCTL16 were expressed at high levels in adult females. In vitro binding assays showed that all five recombinant AsCTLs could bind to different microbial cell wall components, including lipopolysaccharide (LPS), lipid A, peptidoglycan (PG), lipoteichoic acid (LTA), zymosan and laminarin (beta-1,3-glucan). Recombinant AsCTLs also bound to several Gram-negative and Gram-positive bacteria, and could agglutinate bacterial cells. Injection of double-stranded RNAs (dsRNAs) could significantly reduce expression of the five AsCTL mRNAs, and the survival of mosquitoes treated with dsRNA to AsCTLGA5 was significantly decreased after Escherichia coli infection, but did not change significantly after Micrococcus luteus infection compared to the control groups, suggesting that Ar. subalbatus AsCTLGA5 may participate in innate immunity against E. coli.

  10. Antibacterial membrane attack by a pore-forming intestinal C-type lectin

    PubMed Central

    Mukherjee, Sohini; Zheng, Hui; Derebe, Mehabaw; Callenberg, Keith; Partch, Carrie L.; Rollins, Darcy; Propheter, Daniel C.; Rizo, Josep; Grabe, Michael; Jiang, Qiu-Xing; Hooper, Lora V.

    2014-01-01

    Summary Human body surface epithelia coexist in close association with complex bacterial communities and are protected by a variety of antibacterial proteins. C-type lectins of the RegIII family are bactericidal proteins that limit direct contact between bacteria and the intestinal epithelium and thus promote tolerance to the intestinal microbiota1,2. RegIII lectins recognize their bacterial targets by binding peptidoglycan carbohydrate1,3 but the mechanism by which they kill bacteria is unknown. Here we elucidate the mechanistic basis for RegIII bactericidal activity. Here we show that human RegIIIα (hRegIIIα, also known as HIP/PAP) binds membrane phospholipids and kills bacteria by forming a hexameric membrane-permeabilizing oligomeric pore. We derive a three-dimensional model of the hRegIIIα pore by docking the hRegIIIα crystal structure into a cryo-electron microscopic map of the pore complex, and show that the model accords with experimentally determined properties of the pore. Lipopolysaccharide inhibits hRegIIIα pore-forming activity, explaining why hRegIIIα is bactericidal for Gram-positive but not Gram-negative bacteria. Our findings identify C-type lectins as mediators of membrane attack in the mucosal immune system, and provide detailed insight into an antibacterial mechanism that promotes mutualism with the resident microbiota. PMID:24256734

  11. A single-CRD C-type lectin is important for bacterial clearance in the silkworm.

    PubMed

    Zhan, Ming-Yue; Shahzad, Toufeeq; Yang, Pei-Jin; Liu, Su; Yu, Xiao-Qiang; Rao, Xiang-Jun

    2016-12-01

    C-type lectins (CTLs) depend on the carbohydrate-recognition domain (CRD) to recognize carbohydrates by a Ca(2+)-dependent mechanism. In animals, CTLs play critical roles in pathogen recognition, activation of the complement system and signaling pathways. Immulectins (Dual-CRD CTLs) in lepidopteran are involved in recognizing pathogens. However, little is known about the immune-related functions of insect single-CRD CTLs. Here, we reported the characterization of C-type lectin-S3 (CTL-S3), a single-CRD CTL from the domesticated silkmoth Bombyx mori (Lepidoptera: Bombycidae). The ORF of CTL-S3 gene is 672 bp, which encodes a putative protein of 223 amino acids. CTL-S3 gene was expressed in a variety of tissues. Levels of CTL-S3 mRNA in fertilized eggs and whole larvae were elevated upon bacterial challenges. CTL-S3 was secreted to larval hemolymph. The recombinant protein (rCTL-S3) binds to bacterial cell wall components and bacteria. CTL-S3 inhibited the growth of Bacillus subtilis and caused agglutination of Staphylococcus aureus. More importantly, CTL-S3 facilitated the rapid clearance of Escherichia coli and Staphylococcus aureus from the body cavity of larvae. Taken together, our results suggested that CTL-S3 may function as an opsonin in larval hemolymph to enhance the clearance of pathogens. PMID:27519466

  12. Evolutionary analysis reveals collective properties and specificity in the C-type lectin and lectin-like domain superfamily.

    PubMed

    Ebner, Sharon; Sharon, Nathan; Ben-Tal, Nir

    2003-10-01

    Members of the C-type lectin/C-type lectin-like domain (CTL/CTLD) superfamily share a common fold and are involved in a variety of functions, such as generalized defense mechanisms against foreign agents, discrimination between healthy and pathogen-infected cells, and endocytosis and blood coagulation. In this work we used ConSurf, a computer program recently developed in our lab, to perform an evolutionary analysis of this superfamily in order to further identify characteristics of all or part of its members. Given a set of homologous proteins in the form of multiple sequence alignment (MSA) and an inferred phylogenetic tree, ConSurf calculates the conservation score in every alignment position, taking into account the relationships between the sequences and the physicochemical similarity between the amino acids. The scores are then color-coded onto the three-dimensional structure of one of the homologous proteins. We provide here and at http://ashtoret.tau.ac.il/ approximately sharon a detailed analysis of the conservation pattern obtained for the entire superfamily and for two subgroups of proteins: (a) 21 CTLs and (b) 11 heterodimeric CTLD toxins. We show that, in general, proteins of the superfamily have one face that is constructed mostly of conserved residues and another that is not, and we suggest that the former face is involved in binding to other proteins or domains. In the CTLs examined we detected a region of highly conserved residues, corresponding to the known calcium- and carbohydrate-binding site of the family, which is not conserved throughout the entire superfamily, and in the CTLD toxins we found a patch of highly conserved residues, corresponding to the known dimerization region of these proteins. Our analysis also detected patches of conserved residues with yet unknown function(s).

  13. Characterization of Multisugar-Binding C-Type Lectin (SpliLec) from a Bacterial-Challenged Cotton Leafworm, Spodoptera littoralis

    PubMed Central

    Seufi, AlaaEddeen M.; Galal, Fatma H.; Hafez, Elsayed E.

    2012-01-01

    Background Various proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized. Methodology A single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too. Conclusions Our results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis. PMID:22916161

  14. Overexpression of a C-type lectin enhances bacterial resistance in red swamp crayfish Procambarus clarkii.

    PubMed

    Zhang, Xiao-Wen; Liu, Ying-Ying; Mu, Yi; Ren, Qian; Zhao, Xiao-Fan; Wang, Jin-Xing

    2013-05-01

    C-type lectins play important roles in the innate immune system of crustaceans. In this study, a novel C-type lectin gene, designated as PcLec4, was obtained from the red swamp crayfish (Procambarus clarkii). Quantitative real-time polymerase chain reaction revealed that PcLec4 is mainly expressed in the crayfish hepatopancreas and intestine, and the PcLec4 mRNA expression is upregulated after challenged with the bacteria Vibrio anguillarum. PcLec4 was recombinantly expressed in Escherichia coli and anti-PcLec4 polyclonal antiserum was prepared. Binding experiments revealed that the recombinant PcLec4 binds to various bacteria and polysaccharides on the bacterial surface, which suggests that PcLec4 recognizes bacterial pathogens. Overexpression of PcLec4 in crayfish using the pIeLec4 vector was performed. The results show that the crayfish overexpressing PcLec4 eliminate injected V. anguillarum more quickly than the control, which suggests that PcLec4 elicits further immune response for removing invading bacteria. The results of the survival experiment confirmed the function of PcLec4 in resisting V. anguillarum because PcLec4 overexpression in crayfish significantly increased the crayfish survival rate. These results reveal that PcLec4 has an important role in the antibacterial immunity of crayfish, and in vivo PcLec4 overexpression might be used as a disease control strategy in aquiculture.

  15. Collaboration between a soluble C-type lectin and calreticulin facilitates white spot syndrome virus infection in shrimp.

    PubMed

    Wang, Xian-Wei; Xu, Yi-Hui; Xu, Ji-Dong; Zhao, Xiao-Fan; Wang, Jin-Xing

    2014-09-01

    White spot syndrome virus (WSSV) mainly infects crustaceans through the digestive tract. Whether C-type lectins (CLs), which are important receptors for many viruses, participate in WSSV infection in the shrimp stomach remains unknown. In this study, we orally infected kuruma shrimp Marsupenaeus japonicus to model the natural transmission of WSSV and identified a CL (designated as M. japonicus stomach virus-associated CL [MjsvCL]) that was significantly induced by virus infection in the stomach. Knockdown of MjsvCL expression by RNA interference suppressed the virus replication, whereas exogenous MjsvCL enhanced it. Further analysis by GST pull-down and coimmunoprecipitation showed that MjsvCL could bind to viral protein 28, the most abundant and functionally relevant envelope protein of WSSV. Furthermore, cell-surface calreticulin was identified as a receptor of MjsvCL, and the interaction between these proteins was a determinant for the viral infection-promoting activity of MjsvCL. The MjsvCL-calreticulin pathway facilitated virus entry likely in a cholesterol-dependent manner. This study provides insights into a mechanism by which soluble CLs capture and present virions to the cell-surface receptor to facilitate viral infection. PMID:25070855

  16. The Structure of the Poxvirus A33 Protein Reveals a Dimer of Unique C-Type Lectin-Like Domains

    SciTech Connect

    Su, Hua-Poo; Singh, Kavita; Gittis, Apostolos G.; Garboczi, David N.

    2010-11-03

    The current vaccine against smallpox is an infectious form of vaccinia virus that has significant side effects. Alternative vaccine approaches using recombinant viral proteins are being developed. A target of subunit vaccine strategies is the poxvirus protein A33, a conserved protein in the Chordopoxvirinae subfamily of Poxviridae that is expressed on the outer viral envelope. Here we have determined the structure of the A33 ectodomain of vaccinia virus. The structure revealed C-type lectin-like domains (CTLDs) that occur as dimers in A33 crystals with five different crystal lattices. Comparison of the A33 dimer models shows that the A33 monomers have a degree of flexibility in position within the dimer. Structural comparisons show that the A33 monomer is a close match to the Link module class of CTLDs but that the A33 dimer is most similar to the natural killer (NK)-cell receptor class of CTLDs. Structural data on Link modules and NK-cell receptor-ligand complexes suggest a surface of A33 that could interact with viral or host ligands. The dimer interface is well conserved in all known A33 sequences, indicating an important role for the A33 dimer. The structure indicates how previously described A33 mutations disrupt protein folding and locates the positions of N-linked glycosylations and the epitope of a protective antibody.

  17. Macrophage-inducible C-type lectin underlies obesity-induced adipose tissue fibrosis.

    PubMed

    Tanaka, Miyako; Ikeda, Kenji; Suganami, Takayoshi; Komiya, Chikara; Ochi, Kozue; Shirakawa, Ibuki; Hamaguchi, Miho; Nishimura, Satoshi; Manabe, Ichiro; Matsuda, Takahisa; Kimura, Kumi; Inoue, Hiroshi; Inagaki, Yutaka; Aoe, Seiichiro; Yamasaki, Sho; Ogawa, Yoshihiro

    2014-09-19

    In obesity, a paracrine loop between adipocytes and macrophages augments chronic inflammation of adipose tissue, thereby inducing systemic insulin resistance and ectopic lipid accumulation. Obese adipose tissue contains a unique histological structure termed crown-like structure (CLS), where adipocyte-macrophage crosstalk is known to occur in close proximity. Here we show that Macrophage-inducible C-type lectin (Mincle), a pathogen sensor for Mycobacterium tuberculosis, is localized to macrophages in CLS, the number of which correlates with the extent of interstitial fibrosis. Mincle induces obesity-induced adipose tissue fibrosis, thereby leading to steatosis and insulin resistance in liver. We further show that Mincle in macrophages is crucial for CLS formation, expression of fibrosis-related genes and myofibroblast activation. This study indicates that Mincle, when activated by an endogenous ligand released from dying adipocytes, is involved in adipose tissue remodelling, thereby suggesting that sustained interactions between adipocytes and macrophages within CLS could be a therapeutic target for obesity-induced ectopic lipid accumulation.

  18. The Macrophage Galactose-Type C-Type Lectin (MGL) Modulates Regulatory T Cell Functions

    PubMed Central

    Zizzari, Ilaria Grazia; Martufi, Paola; Battisti, Federico; Rahimi, Hassan; Caponnetto, Salvatore; Bellati, Filippo; Nuti, Marianna

    2015-01-01

    Regulatory T cells (Tregs) are physiologically designed to prevent autoimmune disease and maintain self-tolerance. In tumour microenvironments, their presence is related to a poor prognosis, and they influence the therapeutic outcome due to their capacity to suppress the immune response by cell-cell contact and to release immunosuppressive cytokines. In this study, we demonstrate that Treg immunosuppressive activity can be modulated by the cross-linking between the CD45RA expressed by Tregs and the C-type lectin MGL. This specific interaction strongly decreases the im-munosuppressive activity of Tregs, restoring the proliferative capacity of co-cultured T lymphocytes. This effect can be attributed to changes in CD45RA and TCR signalling through the inhibition of Lck and inactivation of Zap-70, an increase in the Foxp3 methylation status and, ultimately, the reduced production of suppressive cytokines. These results indicate a role of MGL as an immunomodulator within the tumour microenvironment interfering with Treg functions, suggesting its possible use in the design of anticancer vaccines. PMID:26147970

  19. A novel method for the purification of low soluble recombinant C-type lectin proteins.

    PubMed

    Yin, Chunhui; Jia, Ying; Garcia, Carlos A

    2012-08-31

    Snake venoms contain a complex mixture of many biological molecules including proteins. The purification of recombinant proteins is a key step in studying their function and structure with affinity chromatography as the common method used in their purification. In bacterial expression systems, hydrophobic recombinant proteins are usually precipitated into inclusion bodies, and contaminants are typically associated with tagged proteins after purification. The purpose of this study was to develop a procedure to purify hydrophobic recombinant proteins without an affinity tag. Snake venom mature C-type lectin-like proteins (CLPs) with a tag were cloned, expressed, and purified by repeated sonication and wash steps. The effects of the signal peptide on the expression and solubility of the recombinant protein were investigated. The CLPs in washed inclusion bodies were solubilized and refolded by dialysis. The CLPs without a tag were successfully purified with a yield 38 times higher than the traditional method, and inhibited blood platelet aggregation with an IC(50) of 100.57 μM in whole blood. This novel procedure is a rapid, and inexpensive method to purify functional recombinant hydrophobic CLPs from snake venoms useful in the development of drug therapies. PMID:22867876

  20. Differential expression of skin mucus C-type lectin in two freshwater eel species, Anguilla marmorata and Anguilla japonica.

    PubMed

    Tsutsui, Shigeyuki; Yoshinaga, Tatsuki; Komiya, Kaoru; Yamashita, Hiroka; Nakamura, Osamu

    2016-08-01

    Two types of lactose-specific lectins, galectin (AJL-1) and C-type lectin (AJL-2), were previously identified in the mucus of adult Anguilla japonica. Here, we compared the expression profiles of these two homologous lectins at the adult and juvenile stages between the tropical eel Anguilla marmorata and the temperate eel A. japonica. Only one lectin, predicted to be an orthologue of AJL-1 by LC-MS/MS, was detected in the mucus of adult A. marmorata. We also found that an orthologous gene to AJL-2 was expressed at very low levels, or not at all, in the skin of adult A. marmorata. However, we detected the gene expression of an AJL-2-orthologue in the skin of juvenile A. marmorata, and a specific antibody also detected the lectin in the juvenile fish epidermis. These findings suggest that expression profiles of mucosal lectins vary during development as well as between species in the Anguilla genus.

  1. Differential expression of skin mucus C-type lectin in two freshwater eel species, Anguilla marmorata and Anguilla japonica.

    PubMed

    Tsutsui, Shigeyuki; Yoshinaga, Tatsuki; Komiya, Kaoru; Yamashita, Hiroka; Nakamura, Osamu

    2016-08-01

    Two types of lactose-specific lectins, galectin (AJL-1) and C-type lectin (AJL-2), were previously identified in the mucus of adult Anguilla japonica. Here, we compared the expression profiles of these two homologous lectins at the adult and juvenile stages between the tropical eel Anguilla marmorata and the temperate eel A. japonica. Only one lectin, predicted to be an orthologue of AJL-1 by LC-MS/MS, was detected in the mucus of adult A. marmorata. We also found that an orthologous gene to AJL-2 was expressed at very low levels, or not at all, in the skin of adult A. marmorata. However, we detected the gene expression of an AJL-2-orthologue in the skin of juvenile A. marmorata, and a specific antibody also detected the lectin in the juvenile fish epidermis. These findings suggest that expression profiles of mucosal lectins vary during development as well as between species in the Anguilla genus. PMID:27026508

  2. The dendritic cell subtype-restricted C-type lectin Clec9A is a target for vaccine enhancement

    PubMed Central

    Proietto, Anna I.; Ahmet, Fatma; Kitsoulis, Susie; Shin Teh, Joo; Lo, Jennifer C. Y.; Rizzitelli, Alexandra; Wu, Li; Vremec, David; van Dommelen, Serani L. H.; Campbell, Ian K.; Maraskovsky, Eugene; Braley, Hal; Davey, Gayle M.; Mottram, Patricia; van de Velde, Nicholas; Jensen, Kent; Lew, Andrew M.; Wright, Mark D.; Heath, William R.; Shortman, Ken

    2008-01-01

    A novel dendritic cell (DC)–restricted molecule, Clec9A, was identified by gene expression profiling of mouse DC subtypes. Based on sequence similarity, a human ortholog was identified. Clec9A encodes a type II membrane protein with a single extracellular C-type lectin domain. Both the mouse Clec9A and human CLEC9A were cloned and expressed, and monoclonal antibodies (mAbs) against each were generated. Surface staining revealed that Clec9A was selective for mouse DCs and was restricted to the CD8+ conventional DC and plasmacytoid DC subtypes. A subset of human blood DCs also expressed CLEC9A. A single injection of mice with a mAb against Clec9A, which targets antigens (Ags) to the DCs, produced a striking enhancement of antibody responses in the absence of added adjuvants or danger signals, even in mice lacking Toll-like receptor signaling pathways. Such targeting also enhanced CD4 and CD8 T-cell responses. Thus, Clec9A serves as a new marker to distinguish subtypes of both mouse and human DCs. Furthermore, targeting Ags to DCs with antibodies to Clec9A is a promising strategy to enhance the efficiency of vaccines, even in the absence of adjuvants. PMID:18669894

  3. Identification of C-type lectin-domain proteins (CTLDPs) in silkworm Bombyx mori.

    PubMed

    Rao, Xiang-Jun; Shahzad, Toufeeq; Liu, Su; Wu, Peng; He, Yan-Ting; Sun, Wei-Jia; Fan, Xiang-Yun; Yang, Yun-Fan; Shi, Qiao; Yu, Xiao-Qiang

    2015-12-01

    C-type lectins (CTLs) represent a large family of proteins that can bind carbohydrate moieties normally in a calcium-dependent manner. CTLs play important roles in mediating cell adhesion and the recognition of pathogens in the immune system. In the present study, we have identified 23 CTL genes in domestic silkworm Bombyx mori. CTL-domain proteins (CTLDPs) are classified into three groups based on the number of carbohydrate-recognition domains (CRDs) and the domain architectures. These include twelve CTL-S (Single-CRD), six immulectins (Dual-CRD) and five CTL-X (CRD with other domains). We studied their phylogenetic features, analyzed the conserved residues, predicted tertiary structures, and examined the tissue expression profile and immune inducibility. Through bioinformatics analysis, we have putatively identified ten secretory and two cytoplasmic CTL-S; four secretory and two cytoplasmic immulectins; one secretory, one cytoplasmic and three transmembrane forms of CTL-X. Most B. mori CTLDPs form monophyletic groups with orthologs from Lepidoptera, Diptera, Coleoptera and Hymenoptera species. Immulectins of B. mori and Manduca sexta evolved from common ancestor genes perhaps due to gene duplication events of CTL-S ancestor genes. Homology modeling revealed that the overall structures of B. mori CTL domains are analogous to those of humans with a variable loop region. We examined the expression profile of CTLDP genes in naïve and immune-stimulated tissues. The expression and induction of CTLDP genes were related to the tissues and microorganisms. Together, our gene identification, sequence comparison, phylogenetic analysis, homology modeling and expression analysis laid a good foundation for the further studies of B. mori CTLDPs and comparative genomics.

  4. Identification of C-type lectin-domain proteins (CTLDPs) in silkworm Bombyx mori.

    PubMed

    Rao, Xiang-Jun; Shahzad, Toufeeq; Liu, Su; Wu, Peng; He, Yan-Ting; Sun, Wei-Jia; Fan, Xiang-Yun; Yang, Yun-Fan; Shi, Qiao; Yu, Xiao-Qiang

    2015-12-01

    C-type lectins (CTLs) represent a large family of proteins that can bind carbohydrate moieties normally in a calcium-dependent manner. CTLs play important roles in mediating cell adhesion and the recognition of pathogens in the immune system. In the present study, we have identified 23 CTL genes in domestic silkworm Bombyx mori. CTL-domain proteins (CTLDPs) are classified into three groups based on the number of carbohydrate-recognition domains (CRDs) and the domain architectures. These include twelve CTL-S (Single-CRD), six immulectins (Dual-CRD) and five CTL-X (CRD with other domains). We studied their phylogenetic features, analyzed the conserved residues, predicted tertiary structures, and examined the tissue expression profile and immune inducibility. Through bioinformatics analysis, we have putatively identified ten secretory and two cytoplasmic CTL-S; four secretory and two cytoplasmic immulectins; one secretory, one cytoplasmic and three transmembrane forms of CTL-X. Most B. mori CTLDPs form monophyletic groups with orthologs from Lepidoptera, Diptera, Coleoptera and Hymenoptera species. Immulectins of B. mori and Manduca sexta evolved from common ancestor genes perhaps due to gene duplication events of CTL-S ancestor genes. Homology modeling revealed that the overall structures of B. mori CTL domains are analogous to those of humans with a variable loop region. We examined the expression profile of CTLDP genes in naïve and immune-stimulated tissues. The expression and induction of CTLDP genes were related to the tissues and microorganisms. Together, our gene identification, sequence comparison, phylogenetic analysis, homology modeling and expression analysis laid a good foundation for the further studies of B. mori CTLDPs and comparative genomics. PMID:26187302

  5. A shrimp C-type lectin inhibits proliferation of the hemolymph microbiota by maintaining the expression of antimicrobial peptides.

    PubMed

    Wang, Xian-Wei; Xu, Ji-Dong; Zhao, Xiao-Fan; Vasta, Gerardo Raul; Wang, Jin-Xing

    2014-04-25

    Some aquatic invertebrates such as shrimp contain low albeit stable numbers of bacteria in the circulating hemolymph. The proliferation of this hemolymph microbiota in such a nutrient-rich environment is tightly controlled in healthy animals, but the mechanisms responsible had remained elusive. In the present study, we report a C-type lectin (MjHeCL) from the kuruma shrimp (Marsupenaeus japonicus) that participates in restraining the hemolymph microbiota. Although the expression of MjHeCL did not seem to be modulated by bacterial challenge, the down-regulation of its expression by RNA interference led to proliferation of the hemolymph microbiota, ultimately resulting in shrimp death. This phenotype was rescued by the injection of recombinant MjHeCL, which restored the healthy status of the knockdown shrimp. A mechanistic analysis revealed that MjHeCL inhibited bacterial proliferation by modulating the expression of antimicrobial peptides. The key function of MjHeCL in the shrimp immune homeostasis might be related to its broader recognition spectrum of the hemolymph microbiota components than other lectins. Our study demonstrates the role of MjHeCL in maintaining the healthy status of shrimp and provides new insight into the biological significance of C-type lectins, a diversified and abundant lectin family in invertebrate species.

  6. A C-type lectin with an immunoglobulin-like domain promotes phagocytosis of hemocytes in crayfish Procambarus clarkii

    PubMed Central

    Zhang, Xiao-Wen; Wang, Yue; Wang, Xian-Wei; Wang, Lei; Mu, Yi; Wang, Jin-Xing

    2016-01-01

    C-type lectins are important immune molecules that participate in host defense response. The present work reports a novel C-type lectin (PcLec3) from the red swamp crayfish Procambarus clarkii. Sequence analysis found that PcLec3 encodes a polypeptide with252 amino acid residues, which contains an immunoglobulin-like domain (IG) and a C-type lectin domain (CTLD) arranged in tandem. Tissue distribution analysis indicated that PcLec3 is enriched expressed in hemocytes and hepatopancreas cells, in which PcLec3 was up-regulated following bacterial challenge by Vibrio anguillarum. Function analysis using recombinant full-length PcLec3, IG, and CTLD proteins revealed that these recombinant proteins had the capacity to bind carbohydrates and bacteria, while IG determined the cell binding activity. However, only full-length PcLec3 promotes the phagocytic activity of hemocytes and subsequent clearance of invasive bacteria. Taken together, these results manifest that PcLec3 acts as a hemocyte adhesion molecule to promote hemocyte phagocytosis against invasive V. anguillarum. PMID:27411341

  7. A C-type lectin fold gene from Japanese scallop Mizuhopecten yessoensis, involved with immunity and metamorphosis.

    PubMed

    Bao, X B; He, C B; Fu, C D; Wang, B; Zhao, X M; Gao, X G; Liu, W D

    2015-01-01

    C-type lectins are a superfamily of Ca(2+)-dependent carbohydrate-recognition proteins that are well known for their participation in pathogen recognition and clearance. In this study, a putative C-type lectin fold (MyCLF) gene was identified from the Japanese scallop Mizuhopecten yessoensis. The full-length of MyCLF was 645 bp, encoding a polypeptide of 167 amino acids. MyCLF carried a signal peptide of 20 amino acid residues, and a single carbohydrate recognition domain, having relatively high amino acid sequence conservation with C-type lectins reported for other bivalves. The expression of MyCLF mRNA transcripts in adult tissues, after bacterial challenge and during different developmental stages was determined using real-time quantitative RT-PCR. MyCLF was mainly distributed in the mantle, gill, and kidney. The expression of MyCLF clearly increased 3 h after Vibrio anguillarum challenge, and dropped to a minimum level after 9 h compared to the control group. During embryonic development, the expression level increased in the gastrulae, trochophore and early D-shaped larvae, decreased in D-shaped larvae, and then increased hundreds of times in metamorphosing larvae. The results suggested that MyCLF was involved in an immune response and it may play important roles during the metamorphosis phase of M. yessoensis. PMID:25867372

  8. A C-type lectin with an immunoglobulin-like domain promotes phagocytosis of hemocytes in crayfish Procambarus clarkii.

    PubMed

    Zhang, Xiao-Wen; Wang, Yue; Wang, Xian-Wei; Wang, Lei; Mu, Yi; Wang, Jin-Xing

    2016-01-01

    C-type lectins are important immune molecules that participate in host defense response. The present work reports a novel C-type lectin (PcLec3) from the red swamp crayfish Procambarus clarkii. Sequence analysis found that PcLec3 encodes a polypeptide with252 amino acid residues, which contains an immunoglobulin-like domain (IG) and a C-type lectin domain (CTLD) arranged in tandem. Tissue distribution analysis indicated that PcLec3 is enriched expressed in hemocytes and hepatopancreas cells, in which PcLec3 was up-regulated following bacterial challenge by Vibrio anguillarum. Function analysis using recombinant full-length PcLec3, IG, and CTLD proteins revealed that these recombinant proteins had the capacity to bind carbohydrates and bacteria, while IG determined the cell binding activity. However, only full-length PcLec3 promotes the phagocytic activity of hemocytes and subsequent clearance of invasive bacteria. Taken together, these results manifest that PcLec3 acts as a hemocyte adhesion molecule to promote hemocyte phagocytosis against invasive V. anguillarum. PMID:27411341

  9. Cloning and characterization of a mannose binding C-type lectin gene from salivary gland of Aedes albopictus

    PubMed Central

    2014-01-01

    Background The studies on sialomes have shown that hematophagous mosquito saliva consists of a lot of pharmacologically active proteins, in which C-type lectins have been identified and regarded as an important component of saliva. The previous studies showed that C-type lectins play crucial roles not only in innate immunity but also in promoting disease transmission in mammals. However, the function and mechanism of C-type lectins from the mosquito sialome is still elusive. Methods A putative C-type lectin gene (Aalb_CTL1) was cloned and expressed from Aedes albopictus by RT-PCR. The deduced amino acid sequence was analyzed by bioinformatic methods. The gene expression profiles in different tissues and various blood-fed stages of Ae. albopictus were examined by Real-Time qRT-PCR and the biological functions of the recombined mature Aalb_CTL1 were tested by hemagglutination and sugar inhibitory agglutination assays. Moreover, the capabilities of rAalb_CTL1 against microorganisms were measured by microbial-agglutination assay. Results The full-length Open reading frame (ORF) of Aalb_CTL1 consisted of 462 bp, encoding 153 amino acid residues. The deduced amino acid sequence contained a putative signal peptide of 19 amino acids. It also contained a CRD domain with a WND (Trp137-Asn138-Asp-139) motif that needed calcium for the hemagglutinating activity and an imperfect EPS (Glu128-Pro129-Ser130) motif that had a predicted ligand binding specificity for mannose. The mRNA level of Aalb_CTL1 was much higher in female mosquito salivary gland than those in fat body and midgut which was down-regulated in salivary gland after blood feeding. The rAalb_CTL1 contained not only hemagglutinating activity and a high affinity with mannose but also agglutinating activity against yeast C. albicans and Gram-positive bacteria S. aureus in Ca2+ dependent manner. Conclusion Aalb_CTL1 was a mannose-binding C-type lectin and constituted one of the important components in saliva of Ae

  10. Molecular cloning and immune responsive expression of a novel C-type lectin gene from bay scallop Argopecten irradians.

    PubMed

    Zhu, Ling; Song, Linsheng; Xu, Wei; Qian, Pei-Yuan

    2008-09-01

    C-type lectins are Ca(2+)-dependent carbohydrate-recognition proteins that play crucial roles in innate immunity. The cDNA of C-type lectin (AiCTL1) in the bay scallop Argopecten irradians was cloned by expressed sequence tag (EST) and RACE techniques. The full-length cDNA of AiCTL1 was 660 bp, consisting of a 5'-terminal untranslated region (UTR) of 30 bp and a 3' UTR of 132 bp with a polyadenylation signal sequence AATAAA and a poly(A) tail. The AiCTL1 cDNA encoded a polypeptide of 166 amino acids with a putative signal peptide of 20 amino acid residues and a mature protein of 146 amino acids. The deduced amino acid sequence of AiCTL1 was highly similar to those of the C-type lectins from other animals and contained a typical carbohydrate-recognition domain (CRD) of 121 residues, which has four conserved disulfide-bonded cysteine residues that define the CRD and two additional cysteine residues at the amino terminus. AiCTL1 mRNA was dominantly expressed in the hemocytes of the bay scallop. The temporal expression of AiCTL1 mRNA in hemocytes was increased by 5.7- and 4.9-fold at 6h after injury and 8h after injection of bacteria, respectively. The structural features, high similarity and expression pattern of AiCTL1 indicate that the gene may be involved in injury healing and the immune response in A. irradians.

  11. Molecular cloning and expression analysis of mannose receptor C type 1 in grass carp (Ctenopharyngodon idella).

    PubMed

    Wang, Li; Liu, Lichun; Zhou, Yang; Zhao, Xiaoheng; Xi, Mingjun; Wei, Shun; Fang, Rui; Ji, Wei; Chen, Nan; Gu, Zemao; Liu, Xueqin; Wang, Weimin; Asim, Muhammad; Liu, Xiaoling; Lin, Li

    2014-03-01

    Mannose receptor C type 1 (MRC1) is a pattern-recognition receptor (PRR) which plays a significant role in immune responses. Much work on MRC1 has been done in mammals and birds while little in fish. In this study, we cloned and characterized MRC1 in grass carp (gcMR). The full-length gcMR contained 5291bp encoding a putative protein of 1432 amino acids. The predicted amino acid sequences showed that gcMR contained a signal peptide, a cysteine-rich (CR) domain, a fibronectin type II (FN II) domain, eight C-type lectin-like domains (CTLDs), a transmembrane domain and a short cytoplasmic domain. gcMR were constitutively expressed in different organs with the higher expression in spleen and head kidney. During embryonic development, gcMR transcript levels were highest at cleavage stage. The up-regulation expression of gcMR, IL-1β and TNF-α in liver, spleen, head kidney and intestine after Aeromonas hydrophila infection indicating it involved in innate immune regulation during bacterial infections. PMID:24184700

  12. Function of a novel C-type lectin with two CRD domains from Macrobrachium rosenbergii in innate immunity.

    PubMed

    Huang, Xin; Huang, Ying; Shi, Yan-Ru; Ren, Qian; Wang, Wen

    2015-03-01

    C-type lectins play crucial roles in innate immunity. In the present study, a novel C-type lectin gene, designated as MrCTL, was identified from Macrobrachium rosenbergii. MrCTL contains 2 carbohydrate-recognition domains (CRDs), namely MrCRD1 and MrCRD2. The MrCRD1 contains a QEP motif and MrCRD2 contains a motif of EPD. MrCTL was mainly expressed in the hepatopancreas. The expression level of MrCTL in hepatopancreas was significantly upregulated after a challenge with Vibrio parahaemolyticus or White spot syndrome virus (WSSV). The recombinant MrCTL, MrCRD1 and MrCRD2 have an ability to agglutinate both Gram-negative (V. parahaemolyticus) and Gram-positive bacteria (Staphylococcus aureus) in a calcium dependent manner. The recombinant MrCTL, MrCRD1 and MrCRD2 bind directly to all tested microorganisms. All these results suggested that MrCTL may have important roles in immune defense against invading pathogens in prawns.

  13. Cloning of cDNAs and molecular characterisation of C-type lectin-like proteins from snake venoms.

    PubMed

    Feng, Jian; Chen, Tianbao; Zhou, Mei; Shaw, Chris

    2012-12-15

    C-type lectin-like proteins (CTLPs) isolated from snake venoms are the largest and most complex non-mammalian vertebrate C-type lectin-like domain family. In the present study, we simultaneously amplified four cDNAs encoding different types of CTLP subunits from the venoms of two different species of snakes by RT-PCR with a single sense primer and a nested universal primer - two CTLP subunit-encoding cDNAs were cloned from Deinagkistrodon acutus venom and two from Agkistrodon halys Pallas venom. All four cloned CTLP subunits exhibited typical motifs in their corresponding domain regions but with relatively-low sequence similarities to each other. Compared with previously-published CTLPs, the four cloned CTLPs subunits showed slight variations in the calcium-binding sites and the disulphide bonding patterns. To our knowledge, these data constitute the first example of co-expression of CTLP platelet glycoprotein Ib-binding subunits and coagulation factors in Agkistrodon halys Pallas venom. PMID:23010162

  14. Molecular cloning and expression of a C-type lectin-like protein from orange-spotted grouper Epinephelus coioides.

    PubMed

    Ji, H; Wei, J; Wei, S; Yan, Y; Huang, Y; Huang, X; Zhou, S; Zhou, Y; Qin, Q

    2014-02-01

    A C-type lectin-like protein (Ec-CTLP) was cloned from the grouper Epinephelus coioides. The full-length cDNA of Ec-CTLP was composed of 905 bp with a 522 bp open reading frame that encodes a 174-residue protein. The putative amino acid sequence of Ec-CTLP contains a signal peptide of 19 residues at the N-terminus and a CLECT domain from Cys43 to Arg169 and a conserved imperfect WND (Trp-Asn-Asp) motif. The homologous identity of deduced amino acid sequences is from 32 to 42% with other fishes. The expression of Ec-CTLP was differently upregulated in E. coioides spleen (germline stem) cells after being challenged at 16 and 4° C. Intracellular localization revealed that Ec-CTLP was distributed only in the cytoplasm. Recombinant Ec-CTLP (rEc-CTLP) was expressed in Escherichia coli BL21 (DE3) and purified for mouse Mus musculus anti-Ec-CTLP serum preparation. The rEc-CTLP fusion protein does not possess haemagglutinating activity, but improves survival from frozen bacteria. The survival of bacteria (including gram-negative E. coli and gram-positive Staphylococcus aureus) was positively correlated with the concentration of the rEc-CTLP. These findings can provide clues to help understand the probable C-type lectin in marine fish innate immunity.

  15. C-type lectin Mermaid inhibits dendritic cell mediated HIV-1 transmission to CD4+ T cells.

    PubMed

    Nabatov, Alexey A; de Jong, Marein A W P; de Witte, Lot; Bulgheresi, Silvia; Geijtenbeek, Teunis B H

    2008-09-01

    Dendritic cells (DCs) are important in HIV-1 transmission; DCs capture invading HIV-1 through the interaction of the gp120 oligosaccharides with the C-type lectin DC-SIGN and migrate to the lymphoid tissues where HIV-1 is transmitted to T cells. Thus, the HIV-1 envelope glycoprotein gp120 is an attractive target to prevent interactions with DCs and subsequent viral transmission. Here, we have investigated whether the structural homologue of DC-SIGN, the nematode C-type lectin Mermaid can be used to prevent HIV-1 transmission by DCs. Our data demonstrate that Mermaid interacts with high mannose structures present on HIV-1 gp120 and thereby inhibits HIV-1 binding to DC-SIGN on DCs. Moreover, Mermaid inhibits DC-SIGN-mediated HIV-1 transmission from DC to T cells. We have identified Mermaid as a non-cytotoxic agent that shares the glycan specificity with DC-SIGN and inhibits DC-SIGN-gp120 interaction. The results are important for the anti-HIV-1 microbicide development directed at preventing DC-HIV-1 interactions. PMID:18597806

  16. Identification and expression modulation of a C-type lectin domain family 4 homologue that is highly expressed in monocytes/macrophages in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Johansson, Petronella; Wang, Tiehui; Collet, Bertrand; Corripio-Miyar, Yolanda; Monte, Milena M; Secombes, Christopher J; Zou, Jun

    2016-01-01

    The C-type lectin domain containing (CLEC) receptors including CD209 are expressed in vivo by monocytes, monocyte-derived macrophages and dendritic cells and by in vitro generated monocyte-derived cells. This paper reports the cloning and sequencing of a lectin molecule, CLEC4T1, in rainbow trout that is a homologue of the CLEC4 family. The expression pattern of the CLEC4T1 was investigated in vivo after infection with a bacterial pathogen and in cultured macrophages after modulation with microbial mimics. Trout CLEC4T1 was highly expressed in spleen and head kidney following infection with Yersinia ruckeri. Expression could also be induced in macrophage cultures by LPS but not by Poly I:C, and suggests that the regulation of CLEC4T1 expression in trout varies according to the nature of the stimulant. A polyclonal CLEC4T1 antibody was generated and validated by Western blotting for use in evaluation of CLEC4T1(+) cells by flow cytometry analysis. Freshly isolated adherent trout head kidney cultures, potentially containing macrophages and dendritic cell precursors, showed an increase of CLEC4T1(+) cells (assessed by flow cytometry) upon stimulation with recombinant interleukin-4/13A. The results suggest that CLEC4T1 is a useful marker for further characterisation of monocyte derived antigen presenting cells in fish.

  17. On the quaternary structure of a C-type lectin from Bothrops jararacussu venom--BJ-32 (BjcuL).

    PubMed

    Silva, F P; Alexandre, G M C; Ramos, C H I; De-Simone, S G

    2008-12-15

    BJ-32 (also known as BjcuL) is a C-type lectin from the venom of Bothrops jararacussu with specificity for beta-galactosides and a remarkable ability to agglutinate several species of trypanosomatids. Our objective was to study the oligomerization state of native BJ-32 by using different biophysical and computational methods. Small-angle X-ray light scattering (SAXS) experiments disclosed a compact, globular protein with a radius of gyration of 36.72+/-0.04A and molecular weight calculated as 147.5+/-2.0kDa. From analytical ultracentrifugation analysis, it was determined that the BJ-32 sedimentation profile fits nicely to a decamer model. The analysis of the intrinsic emitted fluorescence spectra for BJ-32 solutions indicated that association of subunits in the decamer is accompanied by changes in the environment of Tryptophan residues. Both ab initio and comparative models of BJ-32 supported the resemblance of the decamer in the crystallographic structure from a close homologue, the rattlesnake venom lectin (RSL) from Crotalus atrox. PMID:18948130

  18. The Neck Region of the C-type Lectin DC-SIGN Regulates Its Surface Spatiotemporal Organization and Virus-binding Capacity on Antigen-presenting Cells*

    PubMed Central

    Manzo, Carlo; Torreno-Pina, Juan A.; Joosten, Ben; Reinieren-Beeren, Inge; Gualda, Emilio J.; Loza-Alvarez, Pablo; Figdor, Carl G.; Garcia-Parajo, Maria F.; Cambi, Alessandra

    2012-01-01

    The C-type lectin DC-SIGN expressed on dendritic cells (DCs) facilitates capture and internalization of a plethora of different pathogens. Although it is known that DC-SIGN organizes in nanoclusters at the surface of DCs, the molecular mechanisms responsible for this well defined nanopatterning and role in viral binding remain enigmatic. By combining biochemical and advanced biophysical techniques, including optical superresolution and single particle tracking, we demonstrate that DC-SIGN intrinsic nanoclustering strictly depends on its molecular structure. DC-SIGN nanoclusters exhibited free, Brownian diffusion on the cell membrane. Truncation of the extracellular neck region, known to abrogate tetramerization, significantly reduced nanoclustering and concomitantly increased lateral diffusion. Importantly, DC-SIGN nanocluster dissolution exclusively compromised binding to nanoscale size pathogens. Monte Carlo simulations revealed that heterogeneity on nanocluster density and spatial distribution confers broader binding capabilities to DC-SIGN. As such, our results underscore a direct relationship between spatial nanopatterning, driven by intermolecular interactions between the neck regions, and receptor diffusion to provide DC-SIGN with the exquisite ability to dock pathogens at the virus length scale. Insight into how virus receptors are organized prior to virus binding and how they assemble into functional platforms for virus docking is helpful to develop novel strategies to prevent virus entry and infection. PMID:23019323

  19. Venom of Parasitoid, Pteromalus puparum, Suppresses Host, Pieris rapae, Immune Promotion by Decreasing Host C-Type Lectin Gene Expression

    PubMed Central

    Fang, Qi; Wang, Fei; Gatehouse, John A.; Gatehouse, Angharad M. R.; Chen, Xue-xin; Hu, Cui; Ye, Gong-yin

    2011-01-01

    Background Insect hosts have evolved immunity against invasion by parasitoids, and in co-evolutionary response parasitoids have also developed strategies to overcome host immune systems. The mechanisms through which parasitoid venoms disrupt the promotion of host immunity are still unclear. We report here a new mechanism evolved by parasitoid Pteromalus puparum, whose venom inhibited the promotion of immunity in its host Pieris rapae (cabbage white butterfly). Methodology/Principal Findings A full-length cDNA encoding a C-type lectin (Pr-CTL) was isolated from P. rapae. Quantitative PCR and immunoblotting showed that injection of bacterial and inert beads induced expression of Pr-CTL, with peaks of mRNA and Pr-CTL protein levels at 4 and 8 h post beads challenge, respectively. In contrast, parasitoid venom suppressed Pr-CTL expression when co-injected with beads, in a time and dose-dependent manner. Immunolocalization and immunoblotting results showed that Pr-CTL was first detectable in vesicles present in cytoplasm of granulocytes in host hemolymph, and was then secreted from cells into circulatory fluid. Finally, the secreted Pr-CTL bound to cellular membranes of both granulocytes and plasmatocytes. Injection of double-stranded RNA specific for target gene decreased expression of Pr-CTL, and a few other host immune-related genes. Suppression of Pr-CTL expression also down-regulated antimicrobial and phenoloxidase activities, and reducing phagocytotic and encapsulation rates in host. The inhibitory effect of parasitoid venom on host encapsulation is consistent with its effect in suppressing Pr-CTL expression. Binding assay results showed that recombinant Pr-CTL directly attached to the surface of P. puparum egges. We infer that Pr-CTL may serve as an immune signalling co-effector, first binding to parasitoid eggs, regulating expression of a set of immune-related genes and promoting host immunity. Conclusions/Significance P. puparum venom inhibits promotion of host

  20. Interaction of Helicobacter pylori with C-Type Lectin Dendritic Cell-Specific ICAM Grabbing Nonintegrin

    PubMed Central

    Miszczyk, Eliza; Rudnicka, Karolina; Moran, Anthony P.; Fol, Marek; Kowalewicz-Kulbat, Magdalena; Druszczyńska, Magdalena; Matusiak, Agnieszka; Walencka, Maria; Rudnicka, Wiesława; Chmiela, Magdalena

    2012-01-01

    In this study we asked whether Helicobacter pylori whole cells and lipopolysaccharide (LPS) utilize sugar moieties of Lewis (Le) antigenic determinants to interact with DC-SIGN (dendritic cell specific ICAM grabbing nonintegrin) receptor on dendritic cells (DCs). For this purpose the soluble DC-SIGN/Fc adhesion assay and the THP-1 leukemia cells with induced expression of DC-SIGN were used. We showed that the binding specificity of DC-SIGN with H. pylori LeX/Y positive whole cells and H. pylori LPS of LeX/Y type was fucose dependent, whereas in LeXY negative H. pylori strains and LPS preparations without Lewis determinants, this binding was galactose dependent. The binding of soluble synthetic LeX and LeY to the DC-SIGN-like receptor on THP-1 cells was also observed. In conclusion, the LeXY dependent as well as independent binding of H. pylori whole cells and H. pylori LPS to DC-SIGN was described. Moreover, we demonstrated that THP-1 cells may serve as an in vitro model for the assessment of H. pylori-DC-SIGN interactions mediated by LeX and LeY determinants. PMID:22550396

  1. Conservation of the C-type lectin fold for massive sequence variation in a Treponema diversity-generating retroelement.

    PubMed

    Le Coq, Johanne; Ghosh, Partho

    2011-08-30

    Anticipatory ligand binding through massive protein sequence variation is rare in biological systems, having been observed only in the vertebrate adaptive immune response and in a phage diversity-generating retroelement (DGR). Earlier work has demonstrated that the prototypical DGR variable protein, major tropism determinant (Mtd), meets the demands of anticipatory ligand binding by novel means through the C-type lectin (CLec) fold. However, because of the low sequence identity among DGR variable proteins, it has remained unclear whether the CLec fold is a general solution for DGRs. We have addressed this problem by determining the structure of a second DGR variable protein, TvpA, from the pathogenic oral spirochete Treponema denticola. Despite its weak sequence identity to Mtd (∼16%), TvpA was found to also have a CLec fold, with predicted variable residues exposed in a ligand-binding site. However, this site in TvpA was markedly more variable than the one in Mtd, reflecting the unprecedented approximate 10(20) potential variability of TvpA. In addition, similarity between TvpA and Mtd with formylglycine-generating enzymes was detected. These results provide strong evidence for the conservation of the formylglycine-generating enzyme-type CLec fold among DGRs as a means of accommodating massive sequence variation.

  2. Conservation of the C-type lectin fold for massive sequence variation in a Treponema diversity-generating retroelement

    SciTech Connect

    Le Coq, Johanne; Ghosh, Partho

    2012-06-19

    Anticipatory ligand binding through massive protein sequence variation is rare in biological systems, having been observed only in the vertebrate adaptive immune response and in a phage diversity-generating retroelement (DGR). Earlier work has demonstrated that the prototypical DGR variable protein, major tropism determinant (Mtd), meets the demands of anticipatory ligand binding by novel means through the C-type lectin (CLec) fold. However, because of the low sequence identity among DGR variable proteins, it has remained unclear whether the CLec fold is a general solution for DGRs. We have addressed this problem by determining the structure of a second DGR variable protein, TvpA, from the pathogenic oral spirochete Treponema denticola. Despite its weak sequence identity to Mtd ({approx}16%), TvpA was found to also have a CLec fold, with predicted variable residues exposed in a ligand-binding site. However, this site in TvpA was markedly more variable than the one in Mtd, reflecting the unprecedented approximate 10{sup 20} potential variability of TvpA. In addition, similarity between TvpA and Mtd with formylglycine-generating enzymes was detected. These results provide strong evidence for the conservation of the formylglycine-generating enzyme-type CLec fold among DGRs as a means of accommodating massive sequence variation.

  3. Conservation of the C-type lectin fold for massive sequence variation in a Treponema diversity-generating retroelement

    PubMed Central

    Le Coq, Johanne; Ghosh, Partho

    2011-01-01

    Anticipatory ligand binding through massive protein sequence variation is rare in biological systems, having been observed only in the vertebrate adaptive immune response and in a phage diversity-generating retroelement (DGR). Earlier work has demonstrated that the prototypical DGR variable protein, major tropism determinant (Mtd), meets the demands of anticipatory ligand binding by novel means through the C-type lectin (CLec) fold. However, because of the low sequence identity among DGR variable proteins, it has remained unclear whether the CLec fold is a general solution for DGRs. We have addressed this problem by determining the structure of a second DGR variable protein, TvpA, from the pathogenic oral spirochete Treponema denticola. Despite its weak sequence identity to Mtd (∼16%), TvpA was found to also have a CLec fold, with predicted variable residues exposed in a ligand-binding site. However, this site in TvpA was markedly more variable than the one in Mtd, reflecting the unprecedented approximate 1020 potential variability of TvpA. In addition, similarity between TvpA and Mtd with formylglycine-generating enzymes was detected. These results provide strong evidence for the conservation of the formylglycine-generating enzyme-type CLec fold among DGRs as a means of accommodating massive sequence variation. PMID:21873231

  4. Biochemical and functional characterization of a C-type lectin (BpLec) from Bothrops pauloensis snake venom.

    PubMed

    Castanheira, Letícia Eulálio; Nunes, Débora Cristina de Oliveira; Cardoso, Thomaz Monteiro; Santos, Paula de Souza; Goulart, Luiz Ricardo; Rodrigues, Renata Santos; Richardson, Michael; Borges, Márcia Helena; Yoneyama, Kelly Aparecida Geraldo; Rodrigues, Veridiana M

    2013-03-01

    In the present work, we report the isolation and partial biochemical characterization of BpLec, a C-type lectin purified from Bothrops pauloensis venom by one chromatographic step on an affinity agarose column immobilized with d-galactose. This protein was homogeneous by SDS-PAGE under reducing and nonreducing conditions, and was shown to be a 33.6 kDa homodimer by MALDI TOF analysis. BpLec presented an isoeletric point of 5.36. Its partial sequence of 132 amino acids for each subunit, determined by Edman degradation, revealed high identity (between 86% and 95%) when aligned with sequences of other related proteins. BpLec was capable of agglutinating native dog and cat erythrocytes and this activity was inhibited by β-galactosides and EDTA. Its hemagglutinating activity was abolished at high temperatures and stable in any pH range. BpLec was effective in inhibiting Gram-positive but not Gram-negative bacteria. In addition, BpLec agglutinated promastigote forms of Leishmania (Leishmania) amazonensis. PMID:23178369

  5. Identification and molecular characterization of a C-type lectin-like protein from Chinese shrimp (Fenneropenaeus chinensis).

    PubMed

    Lai, Xiaofang; Kong, Jie; Wang, Qingyin; Wang, Weiji; Meng, Xianhong

    2013-03-01

    A C-type lectin-like protein was cloned and characterized from the Chinese shrimp Fenneropenaeus chinensis, and named as FcCTL. The results indicated that the full length cDNA of 859 bp had an open reading frame encoded a polypeptide of 220 amino acids with one carbohydrate-recognition domain, six conserved Cys and one key motif EPGD. The theoretical molecular weight and pI of mature protein was 25.3 kDa and 5.4. Sequence comparison of the deduced amino acid sequence of FcCTL showed varied identity of 26-34, 34, 31 and 30 % with those of F. chinensis, Portunus trituberculatus, Tetraodon nigroviridis, Penaeus monodon, respectively. qRT-PCR analysis indicated that FcCTL was expressed highest in hepatopancreas of normal shrimp, and it's expression was up-regulated in hepatopancreas and gills post white spot syndrome virus challenge. The purified recombinant FcCTL showed higher antimicrobial activity against Gram-positive bacteria than against Gram-negative bacteria and fungi. And the hemagglutinating activity of rFcCTL could be completely inhibited by GlcNAc (5 μg/ml), LPS (2.5 μg/ml), D-galactose (100 mM) and maltose (100 mM). These data suggested that FcCTL might play an important role in shrimp immune and would be helpful to better understand the innate immunity mechanism of shrimp. PMID:23192616

  6. Insights into anti-parasitism induced by a C-type lectin from Bothrops pauloensis venom on Toxoplasma gondii.

    PubMed

    Castanheira, Letícia; Naves de Souza, Dayane Lorena; Silva, Rafaela José; Barbosa, Bellisa; Mineo, José Roberto; Tudini, Kelly Aparecida; Rodrigues, Renata; Ferro, Eloísa Vieira; de Melo Rodrigues, Veridiana

    2015-03-01

    Here we evaluate the effects of BpLec, a C-type lectin isolated from Bothrops pauloensis snake venom, on Toxoplasma gondii parasitism. BpLec (0.195-12.5 μg/mL) did not interfere with HeLa (host cell) viability by MTT assay, whereas higher doses decreased viability and changed HeLa morphology. In addition, the host cell treatment before infection did not influence adhesion and proliferation indexes. BpLec did not alter T. gondii tachyzoite viability, as carried out by trypan blue exclusion, but decreased both adhesion and parasite replication, when tachyzoites were treated before infection. Galactose (0.4 M) inhibited the BpLec effect on adhesion assays, suggesting that BpLec probably recognize some glycoconjugate from T. gondii membrane. Additionally, we performed cytokine measurements from supernatants collected from HeLa cells infected with T. gondii tachyzoites previously treated with RPMI or BpLec. MIF and IL-6 productions by HeLa cells were increased by BpLec treatment. Also, TGF-β1 secretion was diminished post-infection, although this effect was not dependent on BpLec treatment. Taken together, our results show that BpLec is capable of reducing T. gondii parasitism after tachyzoite treatment and may represent an interesting tool in the search for parasite antigens involved in these processes. PMID:25541358

  7. The C-type lectin-like domain containing proteins Clec-39 and Clec-49 are crucial for Caenorhabditis elegans immunity against Serratia marcescens infection.

    PubMed

    Miltsch, S M; Seeberger, P H; Lepenies, B

    2014-07-01

    Caenorhabditis elegans exhibits protective immunity against a variety of fungal and bacterial pathogens. Since C. elegans lacks an adaptive immune system, pathogen recognition is mediated entirely by innate immunity. To date, little is known about the involvement of pattern recognition receptors (PRRs) in pathogen sensing as part of the C. elegans immunity. C-type lectin-like domain (CTLD) containing proteins represent a superfamily of PRRs. A large number of genes encoding for CTLD proteins are present in the C. elegans genome, however the role of CTLD proteins in bacterial recognition and antibacterial immunity has not yet been determined. In this study, we investigated the function of selected C. elegans CTLD proteins during infection with the Gram-negative bacterium Serratia marcescens. Wild-type and CTLD gene-deficient C. elegans strains were compared in their susceptibility to S. marcescens infection. Interestingly, survival and egg laying were significantly reduced in strains deficient for clec-39 and clec-49 indicating a role for both CTLD proteins in C. elegans immune defense against bacteria as evidenced by using S. marcescens infection. Binding studies with recombinantly expressed Clec-39-Fc and Clec-49-Fc fusion proteins revealed that both CTLD proteins recognized live bacteria in a Ca(2+)-independent manner. This study provides insight into the role of CTLD proteins in C. elegans immunity and demonstrates their function during bacterial infection.

  8. Novel sequences encoding venom C-type lectins are conserved in phylogenetically and geographically distinct Echis and Bitis viper species.

    PubMed

    Harrison, R A; Oliver, J; Hasson, S S; Bharati, K; Theakston, R D G

    2003-10-01

    Envenoming by Echis saw scaled vipers and Bitis arietans puff adders is the leading cause of death and morbidity in Africa due to snake bite. Despite their medical importance, the composition and constituent functionality of venoms from these vipers remains poorly understood. Here, we report the cloning of cDNA sequences encoding seven clusters or isoforms of the haemostasis-disruptive C-type lectin (CTL) proteins from the venom glands of Echis ocellatus, E. pyramidum leakeyi, E. carinatus sochureki and B. arietans. All these CTL sequences encoded the cysteine scaffold that defines the carbohydrate-recognition domain of mammalian CTLs. All but one of the Echis and Bitis CTL sequences showed greater sequence similarity to the beta than alpha CTL subunits in venoms of related Asian and American vipers. Four of the new CTL clusters showed marked inter-cluster sequence conservation across all four viper species which were significantly different from that of previously published viper CTLs. The other three Echis and Bitis CTL clusters showed varying degrees of sequence similarity to published viper venom CTLs. Because viper venom CTLs exhibit a high degree of sequence similarity and yet exert profoundly different effects on the mammalian haemostatic system, no attempt was made to assign functionality to the new Echis and Bitis CTLs on the basis of sequence alone. The extraordinary level of inter-specific and inter-generic sequence conservation exhibited by the Echis and Bitis CTLs leads us to speculate that antibodies to representative molecules should neutralise the biological function of this important group of venom toxins in vipers that are distributed throughout Africa, the Middle East and the Indian subcontinent. PMID:14557069

  9. Crystallization and preliminary X-ray analysis of the C-type lectin domain of the spicule matrix protein SM50 from Strongylocentrotus purpuratus

    PubMed Central

    Juneja, Puneet; Rao, Ashit; Cölfen, Helmut; Diederichs, Kay; Welte, Wolfram

    2014-01-01

    Sea urchin spicules have a calcitic mesocrystalline architecture that is closely associated with a matrix of proteins and amorphous minerals. The mechanism underlying spicule formation involves complex processes encompassing spatio-temporally regulated organic–inorganic interactions. C-type lectin domains are present in several spicule matrix proteins in Strongylocentrotus purpuratus, implying their role in spiculogenesis. In this study, the C-type lectin domain of SM50 was overexpressed, purified and crystallized using a vapour-diffusion method. The crystal diffracted to a resolution of 2.85 Å and belonged to space group P212121, with unit-cell parameters a = 100.6, b = 115.4, c = 130.6 Å, α = β = γ = 90°. Assuming 50% solvent content, six chains are expected to be present in the asymmetric unit. PMID:24637770

  10. Specificity analysis of the C-type lectin from rattlesnake venom, and its selectivity towards Gal- or GalNAc-terminated glycoproteins.

    PubMed

    Young, N Martin; van Faassen, Henk; Watson, David C; Mackenzie, C Roger

    2011-08-01

    The rattlesnake (Crotalus atrox) venom lectin is a readily-prepared decameric C-type lectin, specific for Gal and GalNAc. Glycan microarray analysis showed it reacted with a wide range of glycans, chiefly recognizing sets of compounds with Galβ1-4GlcNAc (LacNAc), α-Gal or α-GalNAc non-reducing termini. Its array profile was therefore distinctly different from those of four previously studied mammalian C-type lectins with the same Gal/GalNAc monosaccharide specificity, and it was more broadly reactive than several Gal- or GalNAc-specific plant lectins commonly used for glycan blotting. Though a general reactivity towards glycoproteins might be expected from the avidity conferred by its high valence, it showed a marked preference for glycoproteins with multiple glycans, terminated by Gal or GalNAc. Thus its ten closely-spaced sites each with a K(D) for GalNAc of ~2 mM appeared to make RSVL more selective than the four more widely-spaced sites of soybean agglutinin, with a ten-fold better K(D) for GalNAc.

  11. Lebecin, a new C-type lectin like protein from Macrovipera lebetina venom with anti-tumor activity against the breast cancer cell line MDA-MB231.

    PubMed

    Jebali, Jed; Fakhfekh, Emna; Morgen, Maram; Srairi-Abid, Najet; Majdoub, Hafedh; Gargouri, Ali; El Ayeb, Mohamed; Luis, José; Marrakchi, Naziha; Sarray, Sameh

    2014-08-01

    C-type lectins like proteins display various biological activities and are known to affect especially platelet aggregation. Few of them have been reported to have anti-tumor effects. In this study, we have identified and characterized a new C-type lectin like protein, named lebecin. Lebecin is a heterodimeric protein of 30 kDa. The N-terminal amino acid sequences of both subunits were determined by Edman degradation and the entire amino acid sequences were deduced from cDNAs. The precursors of both lebecin subunits contain a 23-amino acid residue signal peptide and the mature α and β subunits are composed of 129 and 131 amino acids, respectively. Lebecin is shown to be a potent inhibitor of MDA-MB231 human breast cancer cells proliferation. Furthermore, lebecin dose-dependently inhibited the integrin-mediated attachment of these cells to different adhesion substrata. This novel C-type lectin also completely blocked MDA-MB231 cells migration towards fibronectin and fibrinogen in haptotaxis assays.

  12. Super-resolution imaging of C-type lectin spatial rearrangement within the dendritic cell plasma membrane at fungal microbe contact sites

    NASA Astrophysics Data System (ADS)

    Itano, Michelle; Graus, Matthew; Pehlke, Carolyn; Wester, Michael; Liu, Ping; Lidke, Keith; Thompson, Nancy; Jacobson, Ken; Neumann, Aaron

    2014-08-01

    Dendritic cells express DC-SIGN and CD206, C-type lectins (CTLs) that bind a variety of pathogens and may facilitate pathogen uptake for subsequent antigen presentation. Both proteins form punctate membrane nanodomains (~80 nm) on naïve cells. We analyzed the spatiotemporal distribution of CTLs following host-fungal particle contact using confocal microscopy and three distinct methods of cluster identification and measurement of receptor clusters in super-resolution datasets: DBSCAN, Pair Correlation and a custom implementation of the Getis spatial statistic. Quantitative analysis of confocal and super-resolution images demonstrated that CTL nanodomains become concentrated in the contact site relative to non-contact membrane after the first hour of exposure and established that this recruitment is sustained out to four hours. DC-SIGN nanodomains in fungal contact sites exhibit a 70% area increase and a 38% decrease in interdomain separation. Contact site CD206 nanodomains possess 90% greater area and 42% lower interdomain separation relative to non-contact regions. Contact site CTL clusters appear as disk-shaped domains of approximately 150-175 nm in diameter. The increase in length scale of CTL nanostructure in contact sites suggests that the smaller nanodomains on resting membranes may merge during fungal nanodomain structure, or that they become packed closely enough to achieve sub-resolution inter-domain edge separations of < 30 nm. This study provides evidence of local receptor spatial rearrangements on the nanoscale that occur in the plasma membrane upon pathogen binding and may direct important signaling interactions required to recognize and respond to the presence of a relatively large pathogen.

  13. Macrophage-inducible C-type lectin Mincle-expressing dendritic cells contribute to control of splenic Mycobacterium bovis BCG infection in mice.

    PubMed

    Behler, Friederike; Maus, Regina; Bohling, Jennifer; Knippenberg, Sarah; Kirchhof, Gabriele; Nagata, Masahiro; Jonigk, Danny; Izykowski, Nicole; Mägel, Lavinia; Welte, Tobias; Yamasaki, Sho; Maus, Ulrich A

    2015-01-01

    The macrophage-inducible C-type lectin Mincle has recently been identified to be a pattern recognition receptor sensing mycobacterial infection via recognition of the mycobacterial cell wall component trehalose-6',6-dimycolate (TDM). However, its role in systemic mycobacterial infections has not been examined so far. Mincle-knockout (KO) mice were infected intravenously with Mycobacterium bovis BCG to mimic the systemic spread of mycobacteria under defined experimental conditions. After intravenous infection with M. bovis BCG, Mincle-KO mice responded with significantly higher numbers of mycobacterial CFU in spleen and liver, while reduced granuloma formation was observed only in the spleen. At the same time, reduced Th1 cytokine production and decreased numbers of gamma interferon-producing T cells were observed in the spleens of Mincle-KO mice relative to the numbers in the spleens of wild-type (WT) mice. The effect of adoptive transfer of defined WT leukocyte subsets generated from bone marrow cells of zDC(+/DTR) mice (which bear the human diphtheria toxin receptor [DTR] under the control of the classical dendritic cell-specific zinc finger transcription factor zDC) to specifically deplete Mincle-expressing classical dendritic cells (cDCs) but not macrophages after diphtheria toxin application on the numbers of splenic and hepatic CFU and T cell subsets was then determined. Adoptive transfer experiments revealed that Mincle-expressing splenic cDCs rather than Mincle-expressing macrophages contributed to the reconstitution of attenuated splenic antimycobacterial immune responses in Mincle-KO mice after intravenous challenge with BCG. Collectively, we show that expression of Mincle, particularly by cDCs, contributes to the control of splenic M. bovis BCG infection in mice.

  14. Super-resolution imaging of C-type lectin spatial rearrangement within the dendritic cell plasma membrane at fungal microbe contact sites

    PubMed Central

    Itano, Michelle S.; Graus, Matthew S.; Pehlke, Carolyn; Wester, Michael J.; Liu, Ping; Lidke, Keith A.; Thompson, Nancy L.; Jacobson, Ken; Neumann, Aaron K.

    2014-01-01

    Dendritic cells express DC-SIGN and CD206, C-type lectins (CTLs) that bind a variety of pathogens and may facilitate pathogen uptake for subsequent antigen presentation. Both proteins form punctate membrane nanodomains (∼80 nm) on naïve cells. We analyzed the spatiotemporal distribution of CTLs following host-fungal particle contact using confocal microscopy and three distinct methods of cluster identification and measurement of receptor clusters in super-resolution datasets: DBSCAN, Pair Correlation and a custom implementation of the Getis spatial statistic. Quantitative analysis of confocal and super-resolution images demonstrated that CTL nanodomains become concentrated in the contact site relative to non-contact membrane after the first hour of exposure and established that this recruitment is sustained out to 4 h. DC-SIGN nanodomains in fungal contact sites exhibit a 70% area increase and a 38% decrease in interdomain separation. Contact site CD206 nanodomains possess 90% greater area and 42% lower interdomain separation relative to non-contact regions. Contact site CTL clusters appear as disk-shaped domains of approximately 150–175 nm in diameter. The increase in length scale of CTL nanostructure in contact sites suggests that the smaller nanodomains on resting membranes may merge during fungal recognition, or that they become packed closely enough to achieve sub-resolution inter-domain edge separations of <30 nm. This study provides evidence of local receptor spatial rearrangements on the nanoscale that occur in the plasma membrane upon pathogen binding and may direct important signaling interactions required to recognize and respond to the presence of a relatively large pathogen. PMID:25506589

  15. PmLT, a C-type lectin specific to hepatopancreas is involved in the innate defense of the shrimp Penaeus monodon.

    PubMed

    Ma, Tracy Hoi-Tung; Benzie, John A H; He, Jian-Guo; Chan, Siu-Ming

    2008-11-01

    A diverse class of proteins called lectins plays a major role in shrimp innate immunity. In this study, the cDNA encoding a C-type lectin of Penaeus monodon (PmLT) was cloned, and its potential role examined. Despite the low overall amino acid sequence identity with other animal lectins, PmLT includes conserved carbohydrate recognition domains (CRDs) characteristic of animal C-type lectins. Unlike the other two P. monodon lectin-like proteins described to date that have one CRD, PmLT has two CRDs. The first CRD contains a QPD motif with specificity for binding galactose, while the second CRD contains a EPN motif for binding mannose. PmLT transcripts can be detected in the hepatopancreas but not in other tissues. Expression studies showed that PmLT mRNA transcript level decreased initially and then gradually increased after whole shrimp or hepatopancreas tissue fragments were treated with white spot syndrome virus (WSSV) extract but were not affected by bacteria. Using anti-rPmLT antibody, PmLT was detected only in the hepatopancreas specific F cells (Hpf). In vitro encapsulation assay showed that agarose beads coated with rPmLT were encapsulated by hemocytes indicating a role in innate immune response. In summary, PmLT is produced in the hepatopancreas and may act as a pattern recognition protein for viral pathogens and also activates the innate immune responses of the shrimp to bacteria. The dual-CRD structure of PmLT may assist the recognition of diverse pathogens.

  16. Interaction of lectins with membrane receptors on erythrocyte surfaces.

    PubMed

    Sung, L A; Kabat, E A; Chien, S

    1985-08-01

    The interactions of human genotype AO erythrocytes (red blood cells) (RBCs) with N-acetylgalactosamine-reactive lectins isolated from Helix pomatia (HPA) and from Dolichos biflorus (DBA) were studied. Binding curves obtained with the use of tritium-labeled lectins showed that the maximal numbers of lectin molecules capable of binding to human genotype AO RBCs were 3.8 X 10(5) and 2.7 X 10(5) molecules/RBC for HPA and DBA, respectively. The binding of one type of lectin may influence the binding of another type. HPA was found to inhibit the binding of DBA, but not vice versa. The binding of HPA was weakly inhibited by a beta-D-galactose-reactive lectin isolated from Ricinus communis (designated RCA1). Limulus polyphemus lectin (LPA), with specificity for N-acetylneuraminic acid, did not influence the binding of HPA but enhanced the binding of DBA. About 80% of LPA receptors (N-acetylneuraminic acid) were removed from RBC surfaces by neuraminidase treatment. Neuraminidase treatment of RBCs resulted in increases of binding of both HPA and DBA, but through different mechanisms. An equal number (7.6 X 10(5) of new HPA sites were generated on genotypes AO and OO RBCs by neuraminidase treatment, and these new sites accounted for the enhancement (AO cells) and appearance (OO cells) of hemagglutinability by HPA. Neuraminidase treatment did not generate new DBA sites, but increased the DBA affinity for the existing receptors; as a result, genotype AO cells increased their hemagglutinability by DBA, while OO cells remained unagglutinable. The use of RBCs of different genotypes in binding assays with 3H-labeled lectins of known specificities provides an experimental system for studying cell-cell recognition and association.

  17. A single-CRD C-type lectin from oyster Crassostrea gigas mediates immune recognition and pathogen elimination with a potential role in the activation of complement system.

    PubMed

    Li, Hui; Zhang, Huan; Jiang, Shuai; Wang, Weilin; Xin, Lusheng; Wang, Hao; Wang, Lingling; Song, Linsheng

    2015-06-01

    C-type lectins (CTLs), serving as pattern recognition receptors (PRRs), are a superfamily of Ca(2+)-dependent carbohydrate-recognition proteins that participate in nonself-recognition and pathogen elimination. In the present study, a single carbohydrate-recognition domain (CRD) CTL was identified from oyster Crassostrea gigas (designated as CgCLec-2). There was only one CRD within the deduced amino acid sequence of CgCLec-2 consisting of 129 amino acid residues. A conserved EPN (Glu246-Pro247-Asn248) motif was found in Ca(2+)-binding site 2 of CgCLec-2. The CgCLec-2 mRNA could be detected in all the examined tissues at different expression levels in oysters. The mRNA expression of CgCLec-2 in hemocytes was up-regulated significantly at 6 h post Vibrio splendidus challenge. The recombinant CgCLec-2 (rCgCLec-2) could bind various Pathogen-Associated Molecular Patterns (PAMPs), including lipopolysaccharide, mannan and peptidoglycan, and displayed strong binding abilities to Vibrio anguillarum, V. splendidus and Yarrowiali polytica and week binding ability to Staphylococcus aureus. It could also enhance the phagocytic activity of oyster hemocytes to V. splendidus and exhibited growth suppression activity against gram-positive bacteria S. aureus but no effect on gram-negative bacteria V. splendidus. Furthermore, the interaction between rCgCLec-2 and rCgMASPL-1 was confirmed by GST Pull down. The results suggested that CgCLec-2 served as not only a PRR in immune recognition but also a regulatory factor in pathogen elimination, and played a potential role in the activation of complement system. PMID:25800112

  18. Preferential induction of CD4+ T cell responses through in vivo targeting of antigen to dendritic cell-associated C-type lectin-1.

    PubMed

    Carter, Robert W; Thompson, Clare; Reid, Delyth M; Wong, Simon Y C; Tough, David F

    2006-08-15

    Targeting of Ags and therapeutics to dendritic cells (DCs) has immense potential for immunotherapy and vaccination. Because DCs are heterogeneous, optimal targeting strategies will require knowledge about functional specialization among DC subpopulations and identification of molecules for targeting appropriate DCs. We characterized the expression of a fungal recognition receptor, DC-associated C-type lectin-1 (Dectin-1), on mouse DC subpopulations and investigated the ability of an anti-Dectin-1 Ab to deliver Ag for the stimulation of immune responses. Dectin-1 was shown to be expressed on CD8alpha-CD4-CD11b+ DCs found in spleen and lymph nodes and dermal DCs present in skin and s.c. lymph nodes. Injection of Ag-anti-Dectin-1 conjugates induced CD4+ and CD8+ T cell and Ab responses at low doses where free Ag failed to elicit a response. Notably, qualitatively different immune responses were generated by targeting Ag to Dectin-1 vs CD205, a molecule expressed on CD8alpha+CD4-CD11b- DCs, dermal DCs, and Langerhans cells. Unlike anti-Dectin-1, anti-CD205 conjugates failed to elicit an Ab response. Moreover, when conjugates were injected i.v., anti-Dectin-1 stimulated a much stronger CD4+ T cell response and a much weaker CD8+ T cell response than anti-CD205. The results reveal Dectin-1 as a potential targeting molecule for immunization and have implications for the specialization of DC subpopulations. PMID:16887988

  19. A single-CRD C-type lectin from oyster Crassostrea gigas mediates immune recognition and pathogen elimination with a potential role in the activation of complement system.

    PubMed

    Li, Hui; Zhang, Huan; Jiang, Shuai; Wang, Weilin; Xin, Lusheng; Wang, Hao; Wang, Lingling; Song, Linsheng

    2015-06-01

    C-type lectins (CTLs), serving as pattern recognition receptors (PRRs), are a superfamily of Ca(2+)-dependent carbohydrate-recognition proteins that participate in nonself-recognition and pathogen elimination. In the present study, a single carbohydrate-recognition domain (CRD) CTL was identified from oyster Crassostrea gigas (designated as CgCLec-2). There was only one CRD within the deduced amino acid sequence of CgCLec-2 consisting of 129 amino acid residues. A conserved EPN (Glu246-Pro247-Asn248) motif was found in Ca(2+)-binding site 2 of CgCLec-2. The CgCLec-2 mRNA could be detected in all the examined tissues at different expression levels in oysters. The mRNA expression of CgCLec-2 in hemocytes was up-regulated significantly at 6 h post Vibrio splendidus challenge. The recombinant CgCLec-2 (rCgCLec-2) could bind various Pathogen-Associated Molecular Patterns (PAMPs), including lipopolysaccharide, mannan and peptidoglycan, and displayed strong binding abilities to Vibrio anguillarum, V. splendidus and Yarrowiali polytica and week binding ability to Staphylococcus aureus. It could also enhance the phagocytic activity of oyster hemocytes to V. splendidus and exhibited growth suppression activity against gram-positive bacteria S. aureus but no effect on gram-negative bacteria V. splendidus. Furthermore, the interaction between rCgCLec-2 and rCgMASPL-1 was confirmed by GST Pull down. The results suggested that CgCLec-2 served as not only a PRR in immune recognition but also a regulatory factor in pathogen elimination, and played a potential role in the activation of complement system.

  20. Ophioluxin, a convulxin-like C-type lectin from Ophiophagus hannah (King cobra) is a powerful platelet activator via glycoprotein VI.

    PubMed

    Du, Xiao-Yan; Clemetson, Jeannine M; Navdaev, Alexei; Magnenat, Edith M; Wells, Timothy N C; Clemetson, Kenneth J

    2002-09-20

    Ophioluxin, a potent platelet agonist, was purified from the venom of Ophiophagus hannah (King cobra). Under nonreducing conditions it has a mass of 85 kDa, similar to convulxin, and on reduction gives two subunits with masses of 16 and 17 kDa, slightly larger than those of convulxin. The N-terminal sequences of both subunits are very similar to those of convulxin and other C-type lectins. Ophioluxin induces a pattern of tyrosine-phosphorylated proteins in platelets like that caused by convulxin, when using appropriate concentrations based on aggregation response, because it is about 2-4 times more powerful as agonist than the latter. Ophioluxin and convulxin induce [Ca(2+)](i) elevation both in platelets and in Dami megakaryocytic cells, and each of these C-type lectins desensitizes responses to the other. Convulxin agglutinates fixed platelets at 2 microg/ml, whereas ophioluxin does not, even at 80 microg/ml. Ophioluxin resembles convulxin more than echicetin or alboaggregin B because polyclonal anti-ophioluxin antibodies recognize both ophioluxin and convulxin, but not echicetin, and platelets adhere to and spread on ophioluxin- or convulxin-precoated surfaces in the same way that is clearly different from their behavior on an alboaggregin B surface. Immobilized ophioluxin was used to isolate the glycoprotein VI-Fcgamma complex from resting platelets, which also contained Fyn, Lyn, Syk, LAT, and SLP76. Ophioluxin is the first multiheterodimeric, convulxin-like snake C-type lectin, as well as the first platelet agonist, to be described from the Elapidae snake family. PMID:12130642

  1. Ophioluxin, a convulxin-like C-type lectin from Ophiophagus hannah (King cobra) is a powerful platelet activator via glycoprotein VI.

    PubMed

    Du, Xiao-Yan; Clemetson, Jeannine M; Navdaev, Alexei; Magnenat, Edith M; Wells, Timothy N C; Clemetson, Kenneth J

    2002-09-20

    Ophioluxin, a potent platelet agonist, was purified from the venom of Ophiophagus hannah (King cobra). Under nonreducing conditions it has a mass of 85 kDa, similar to convulxin, and on reduction gives two subunits with masses of 16 and 17 kDa, slightly larger than those of convulxin. The N-terminal sequences of both subunits are very similar to those of convulxin and other C-type lectins. Ophioluxin induces a pattern of tyrosine-phosphorylated proteins in platelets like that caused by convulxin, when using appropriate concentrations based on aggregation response, because it is about 2-4 times more powerful as agonist than the latter. Ophioluxin and convulxin induce [Ca(2+)](i) elevation both in platelets and in Dami megakaryocytic cells, and each of these C-type lectins desensitizes responses to the other. Convulxin agglutinates fixed platelets at 2 microg/ml, whereas ophioluxin does not, even at 80 microg/ml. Ophioluxin resembles convulxin more than echicetin or alboaggregin B because polyclonal anti-ophioluxin antibodies recognize both ophioluxin and convulxin, but not echicetin, and platelets adhere to and spread on ophioluxin- or convulxin-precoated surfaces in the same way that is clearly different from their behavior on an alboaggregin B surface. Immobilized ophioluxin was used to isolate the glycoprotein VI-Fcgamma complex from resting platelets, which also contained Fyn, Lyn, Syk, LAT, and SLP76. Ophioluxin is the first multiheterodimeric, convulxin-like snake C-type lectin, as well as the first platelet agonist, to be described from the Elapidae snake family.

  2. A novel C-type lectin with four CRDs is involved in the regulation of antimicrobial peptide gene expression in Hyriopsis cumingii.

    PubMed

    Zhao, Ling-Ling; Wang, Yu-Qing; Dai, Yun-Jia; Zhao, Li-Juan; Qin, Qiwei; Lin, Li; Ren, Qian; Lan, Jiang-Feng

    2016-08-01

    C-type lectins (CTLs) are found in a wide number of invertebrates, and have been reported to participate in immune responses, such as the activation of prophenoloxidase, cell adhesion, bacterial clearance and phagocytosis. Previous studies on CTLs focused on the function of their carbohydrate recognition domains (CRDs). Currently, studies on lectins with multi-CRDs are limited. In this study, a lectin with four CRDs was cloned from Hyriopsis cumingii, and called HcLec4. HcLec4 was widely distributed in several tissues and was significantly down-regulated at the early stage (2 h) of bacterial infection. We further analyzed the bacteria and carbohydrate binding activities of HcLec4. The results showed that HcLec4 could bind to several bacteria, lipopolysaccharide (LPS) and peptidoglycan (PGN). In HcLec4 knockdown mussels, the bacterial clearance rate was increased, and the expression level of antimicrobial peptides (AMPs) was up-regulated. This study reveals that HcLec4 exerts its antibacterial effect by regulating the expression of AMPs at the early stage of bacterial infection. PMID:27288254

  3. The Cryptosporidium parvum C-Type Lectin CpClec Mediates Infection of Intestinal Epithelial Cells via Interactions with Sulfated Proteoglycans

    PubMed Central

    Ludington, Jacob G.

    2016-01-01

    The apicomplexan parasite Cryptosporidium causes significant diarrheal disease worldwide. Effective anticryptosporidial agents are lacking, in part because the molecular mechanisms underlying Cryptosporidium-host cell interactions are poorly understood. Previously, we identified and characterized a novel Cryptosporidium parvum C-type lectin domain-containing mucin-like glycoprotein, CpClec. In this study, we evaluated the mechanisms underlying interactions of CpClec with intestinal epithelial cells by using an Fc-tagged recombinant protein. CpClec-Fc displayed Ca2+-dependent, saturable binding to HCT-8 and Caco-2 cells and competitively inhibited C. parvum attachment to and infection of HCT-8 cells. Binding of CpClec-Fc was specifically inhibited by sulfated glycosaminoglycans, particularly heparin and heparan sulfate. Binding was reduced after the removal of heparan sulfate and following the inhibition of glycosaminoglycan synthesis or sulfation in HCT-8 cells. Like CpClec-Fc binding, C. parvum attachment to and infection of HCT-8 cells were inhibited by glycosaminoglycans and were reduced after heparan sulfate removal or inhibition of glycosaminoglycan synthesis or sulfation. Lastly, CpClec-Fc binding and C. parvum sporozoite attachment were significantly decreased in CHO cell mutants defective in glycosaminoglycan synthesis. Together, these results indicate that CpClec is a novel C-type lectin that mediates C. parvum attachment and infection via Ca2+-dependent binding to sulfated proteoglycans on intestinal epithelial cells. PMID:26975991

  4. HdhCTL1 is a novel C-type lectin of abalone Haliotis discus hannai that agglutinates Gram-negative bacterial pathogens.

    PubMed

    Zhang, Jian; Qiu, Reng; Hu, Yong-hua

    2014-12-01

    C-type lectins (CTLs) are Ca(2+)-dependent carbohydrate recognition proteins, which play important roles in the innate immunity of both vertebrates and invertebrates. In this study, we identified and characterized a C-type lectin (named HdhCTL1) from Pacific abalone, Haliotis discus hannai. HdhCTL1 is composed of 176 amino acid residues and shares low (23.9%) identity with the known CTL of abalone. HdhCTL1 possesses a putative signal peptide and a carbohydrate-recognition domain (CRD) typical of CTLs. The CRD of HdhCTL1 contains four disulfide bond-forming cysteine residues that are highly conserved in CTLs. HdhCTL1 mRNA was detected in a wide range of tissues and expressed abundantly in the digestive gland. Experimental infection with the bacterial pathogen Vibrio anguillarum significantly upregulated HdhCTL1 expression in a time-dependent manner. Recombinant HdhCTL1 (rHdhCTL1) purified from Escherichia coli was able to agglutinate Gram-negative bacterial pathogens. The agglutinating ability of rHdhCTL1 was abolished in the presence of mannose. These results suggest that HdhCTL1 is a novel CTL which is likely to be involved in host defense against bacterial infection. PMID:25301718

  5. HdhCTL1 is a novel C-type lectin of abalone Haliotis discus hannai that agglutinates Gram-negative bacterial pathogens.

    PubMed

    Zhang, Jian; Qiu, Reng; Hu, Yong-hua

    2014-12-01

    C-type lectins (CTLs) are Ca(2+)-dependent carbohydrate recognition proteins, which play important roles in the innate immunity of both vertebrates and invertebrates. In this study, we identified and characterized a C-type lectin (named HdhCTL1) from Pacific abalone, Haliotis discus hannai. HdhCTL1 is composed of 176 amino acid residues and shares low (23.9%) identity with the known CTL of abalone. HdhCTL1 possesses a putative signal peptide and a carbohydrate-recognition domain (CRD) typical of CTLs. The CRD of HdhCTL1 contains four disulfide bond-forming cysteine residues that are highly conserved in CTLs. HdhCTL1 mRNA was detected in a wide range of tissues and expressed abundantly in the digestive gland. Experimental infection with the bacterial pathogen Vibrio anguillarum significantly upregulated HdhCTL1 expression in a time-dependent manner. Recombinant HdhCTL1 (rHdhCTL1) purified from Escherichia coli was able to agglutinate Gram-negative bacterial pathogens. The agglutinating ability of rHdhCTL1 was abolished in the presence of mannose. These results suggest that HdhCTL1 is a novel CTL which is likely to be involved in host defense against bacterial infection.

  6. The Cryptosporidium parvum C-Type Lectin CpClec Mediates Infection of Intestinal Epithelial Cells via Interactions with Sulfated Proteoglycans.

    PubMed

    Ludington, Jacob G; Ward, Honorine D

    2016-05-01

    The apicomplexan parasite Cryptosporidium causes significant diarrheal disease worldwide. Effective anticryptosporidial agents are lacking, in part because the molecular mechanisms underlying Cryptosporidium-host cell interactions are poorly understood. Previously, we identified and characterized a novel Cryptosporidium parvum C-type lectin domain-containing mucin-like glycoprotein, CpClec. In this study, we evaluated the mechanisms underlying interactions of CpClec with intestinal epithelial cells by using an Fc-tagged recombinant protein. CpClec-Fc displayed Ca(2+)-dependent, saturable binding to HCT-8 and Caco-2 cells and competitively inhibited C. parvum attachment to and infection of HCT-8 cells. Binding of CpClec-Fc was specifically inhibited by sulfated glycosaminoglycans, particularly heparin and heparan sulfate. Binding was reduced after the removal of heparan sulfate and following the inhibition of glycosaminoglycan synthesis or sulfation in HCT-8 cells. Like CpClec-Fc binding, C. parvum attachment to and infection of HCT-8 cells were inhibited by glycosaminoglycans and were reduced after heparan sulfate removal or inhibition of glycosaminoglycan synthesis or sulfation. Lastly, CpClec-Fc binding and C. parvum sporozoite attachment were significantly decreased in CHO cell mutants defective in glycosaminoglycan synthesis. Together, these results indicate that CpClec is a novel C-type lectin that mediates C. parvum attachment and infection via Ca(2+)-dependent binding to sulfated proteoglycans on intestinal epithelial cells. PMID:26975991

  7. Labeling of lectin receptors during the cell cycle.

    PubMed

    Garrido, J

    1976-12-01

    Labeling of lectin receptors during the cell cycle. (Localizabión de receptores para lectinas durante el ciclo celular). Arch. Biol. Med. Exper. 10: 100-104, 1976. The topographic distribution of specific cell surface receptors for concanavalin A and wheat germ agglutinin was studied by ultrastructural labeling in the course of the cell cycle. C12TSV5 cells were synchronized by double thymidine block or mechanical selection (shakeoff). They were labeled by means of lectin-peroxidase techniques while in G1 S, G2 and M phases of the cycle. The results obtained were similar for both lectins employed. Interphase cells (G1 S, G2) present a stlihtly discontinous labeling pattern that is similar to the one observed on unsynchronized cells of the same line. Cells in mitosis, on the contrary, present a highly discontinous distribution of reaction product. This pattern disappears after the cells enters G1 and is not present on mitotic cells fixed in aldehyde prior to labeling.

  8. Labeling of lectin receptors during the cell cycle.

    PubMed

    Garrido, J

    1976-12-01

    Labeling of lectin receptors during the cell cycle. (Localizabión de receptores para lectinas durante el ciclo celular). Arch. Biol. Med. Exper. 10: 100-104, 1976. The topographic distribution of specific cell surface receptors for concanavalin A and wheat germ agglutinin was studied by ultrastructural labeling in the course of the cell cycle. C12TSV5 cells were synchronized by double thymidine block or mechanical selection (shakeoff). They were labeled by means of lectin-peroxidase techniques while in G1 S, G2 and M phases of the cycle. The results obtained were similar for both lectins employed. Interphase cells (G1 S, G2) present a stlihtly discontinous labeling pattern that is similar to the one observed on unsynchronized cells of the same line. Cells in mitosis, on the contrary, present a highly discontinous distribution of reaction product. This pattern disappears after the cells enters G1 and is not present on mitotic cells fixed in aldehyde prior to labeling. PMID:1030938

  9. Involvement of viral envelope GP2 in Ebola virus entry into cells expressing the macrophage galactose-type C-type lectin

    SciTech Connect

    Usami, Katsuaki; Matsuno, Keita; Igarashi, Manabu; Denda-Nagai, Kaori; Takada, Ayato; Irimura, Tatsuro

    2011-04-01

    Highlights: {yields} Ebola virus infection is mediated by binding to and fusion with the target cells. {yields} Structural feature of the viral glycoprotein determines the infectivity. {yields} Surface C-type lectin, MGL, of macrophages and dendritic cells mediate the infection. {yields} GP2, one of glycoprotein subunits, plays an essential role in MGL-mediated infection. {yields} There is a critical amino acid residue involved in high infectivity. -- Abstract: Ebola virus (EBOV) infection is initiated by the interaction of the viral surface envelope glycoprotein (GP) with the binding sites on target cells. Differences in the mortality among different species of the Ebola viruses, i.e., Zaire ebolavirus (ZEBOV) and Reston ebolavirus (REBOV), correspond to the in vitro infectivity of the pseudo-typed virus constructed with the GPs in cells expressing macrophage galactose-type calcium-type lectin (MGL/CD301). Through mutagenesis of GP2, the transmembrane-anchored subunit of GP, we found that residues 502-527 of the GP2 sequence determined the different infectivity between VSV-ZEBOV GP and -REBOV GP in MGL/CD301-expressing cells and a histidine residue at position 516 of ZEBOV GP2 appeared essential in the differential infectivity. These findings may provide a clue to clarify a molecular basis of different pathogenicity among EBOV species.

  10. Allergy-Protective Arabinogalactan Modulates Human Dendritic Cells via C-Type Lectins and Inhibition of NF-κB.

    PubMed

    Peters, Marcus; Guidato, Patrick M; Peters, Karin; Megger, Dominik A; Sitek, Barbara; Classen, Birgit; Heise, Esther M; Bufe, Albrecht

    2016-02-15

    Arabinogalactan (AG) isolated from dust of a traditional farm prevents disease in murine models of allergy. However, it is unclear whether this polysaccharide has immune regulatory properties in humans. The aim of this study was to test the influence of AG on the immune-stimulating properties of human dendritic cells (DCs). Moreover, we sought to identify the receptor to which AG binds. AG was produced from plant callus tissue under sterile conditions to avoid the influence of pathogen-associated molecular patterns in subsequent experiments. The influence of AG on the human immune system was investigated by analyzing its impact on monocyte-derived DCs. To analyze whether the T cell stimulatory capacity of AG-stimulated DCs is altered, an MLR with naive Th cells was performed. We revealed that AG reduced T cell proliferation in a human MLR. In the search for a molecular mechanism, we found that AG binds to the immune modulatory receptors DC-specific ICAM-3 -: grabbing non integrin (DC-SIGN) and macrophage mannose receptor 1 (MMR-1). Stimulation of these receptors with AG simultaneously with TLR4 stimulation with LPS increased the expression of the E3 ubiquitin-protein ligase tripartite motif -: containing protein 21 and decreased the phosphorylation of NF-κB p65 in DCs. This led to a reduced activation profile with reduced costimulatory molecules and proinflammatory cytokine production. Blocking of MMR-1 or DC-SIGN with neutralizing Abs partially inhibits this effect. We conclude that AG dampens the activation of human DCs by LPS via binding to DC-SIGN and MMR-1, leading to attenuated TLR signaling. This results in a reduced T cell activation capacity of DCs. PMID:26746190

  11. Generation and characterization of β1,2-gluco-oligosaccharide probes from Brucella abortus cyclic β-glucan and their recognition by C-type lectins of the immune system

    PubMed Central

    Zhang, Hongtao; Palma, Angelina S; Zhang, Yibing; Childs, Robert A; Liu, Yan; Mitchell, Daniel A; Guidolin, Leticia S; Weigel, Wilfried; Mulloy, Barbara; Ciocchini, Andrés E; Feizi, Ten; Chai, Wengang

    2016-01-01

    The β1,2-glucans produced by bacteria are important in invasion, survival and immunomodulation in infected hosts be they mammals or plants. However, there has been a lack of information on proteins which recognize these molecules. This is partly due to the extremely limited availability of the sequence-defined oligosaccharides and derived probes for use in the study of their interactions. Here we have used the cyclic β1,2-glucan (CβG) of the bacterial pathogen Brucella abortus, after removal of succinyl side chains, to prepare linearized oligosaccharides which were used to generate microarrays. We describe optimized conditions for partial depolymerization of the cyclic glucan by acid hydrolysis and conversion of the β1,2-gluco-oligosaccharides, with degrees of polymerization 2–13, to neoglycolipids for the purpose of generating microarrays. By microarray analyses, we show that the C-type lectin receptor DC-SIGNR, like the closely related DC-SIGN we investigated earlier, binds to the β1,2-gluco-oligosaccharides, as does the soluble immune effector serum mannose-binding protein. Exploratory studies with DC-SIGN are suggestive of the recognition also of the intact CβG by this receptor. These findings open the way to unravelling mechanisms of immunomodulation mediated by β1,2-glucans in mammalian systems. PMID:27053576

  12. Human antibodies targeting the C-type lectin-like domain of the tumor endothelial cell marker clec14a regulate angiogenic properties in vitro

    PubMed Central

    Ki, M K; Jeoung, M H; Choi, J R; Rho, S-S; Kwon, Y-G; Shim, H; Chung, J; Hong, H J; Song, B D; Lee, S

    2013-01-01

    It has been suggested that clec14a may be involved in tumor angiogenesis. However, a molecular mechanism has not been clearly identified. In this study, we show for the first time that C-type lectin-like domain (CTLD) of clec14a may be important for regulating cell migration and filopodia formation. Using phage display technology, recombinant human antibodies specific to the CTLDs of human and mouse clec14a (clec14a-CTLD (immunoglobulin G) IgG) were selected. Functional assays using the antibodies showed that clec14a-CTLD IgGs specifically blocked endothelial cell migration and tube formation without affecting cell viability or activation. Further, clec14a-CTLD IgGs inhibited clec14a-mediated cell–cell contact by blocking interaction between CTLDs. Finally, clec14a cross-linking by the clec14a-CTLD IgGs significantly downregulated clec14a expression on the surface of endothelial cells. These results strongly suggest that the clec14a-CTLD may be a key domain in angiogenesis, and that clec14a-CTLD IgGs specifically inhibit angiogenesis by modulating CTLD-mediated cell interactions and clec14a expression on the surface of endothelial cells. PMID:23644659

  13. Insights into Collagen Uptake by C-type Mannose Receptors from the Crystal Structure of Endo180 Domains 1-4.

    PubMed

    Paracuellos, Patricia; Briggs, David C; Carafoli, Federico; Lončar, Tan; Hohenester, Erhard

    2015-11-01

    The C-type mannose receptor and its homolog Endo180 (or uPARAP, for urokinase plasminogen activator receptor-associated protein) mediate the endocytic uptake of collagen by macrophages and fibroblasts. This process is required for normal tissue remodeling, but also facilitates the growth and dissemination of tumors. We have determined the crystal structure at 2.5 Å resolution of the N-terminal region of Endo180, consisting of a ricin-like domain, a fibronectin type II (FN2) domain, and two C-type lectin (CTL) domains. The L-shaped arrangement of these domains creates a shallow trench spanning the FN2 and CTL1 domains, which was shown by mutagenesis to bind triple-helical and denatured collagen. Small-angle X-ray scattering showed that the L-shaped structure is maintained in solution at neutral and acidic pH, irrespective of calcium ion loading. Collagen binding was equally unaffected by acidic pH, suggesting that collagen release in endosomes is not regulated by changes within the Endo180 N-terminal region. PMID:26481812

  14. Insights into Collagen Uptake by C-type Mannose Receptors from the Crystal Structure of Endo180 Domains 1-4.

    PubMed

    Paracuellos, Patricia; Briggs, David C; Carafoli, Federico; Lončar, Tan; Hohenester, Erhard

    2015-11-01

    The C-type mannose receptor and its homolog Endo180 (or uPARAP, for urokinase plasminogen activator receptor-associated protein) mediate the endocytic uptake of collagen by macrophages and fibroblasts. This process is required for normal tissue remodeling, but also facilitates the growth and dissemination of tumors. We have determined the crystal structure at 2.5 Å resolution of the N-terminal region of Endo180, consisting of a ricin-like domain, a fibronectin type II (FN2) domain, and two C-type lectin (CTL) domains. The L-shaped arrangement of these domains creates a shallow trench spanning the FN2 and CTL1 domains, which was shown by mutagenesis to bind triple-helical and denatured collagen. Small-angle X-ray scattering showed that the L-shaped structure is maintained in solution at neutral and acidic pH, irrespective of calcium ion loading. Collagen binding was equally unaffected by acidic pH, suggesting that collagen release in endosomes is not regulated by changes within the Endo180 N-terminal region.

  15. Insights into Collagen Uptake by C-type Mannose Receptors from the Crystal Structure of Endo180 Domains 1–4

    PubMed Central

    Paracuellos, Patricia; Briggs, David C.; Carafoli, Federico; Lončar, Tan; Hohenester, Erhard

    2015-01-01

    Summary The C-type mannose receptor and its homolog Endo180 (or uPARAP, for urokinase plasminogen activator receptor-associated protein) mediate the endocytic uptake of collagen by macrophages and fibroblasts. This process is required for normal tissue remodeling, but also facilitates the growth and dissemination of tumors. We have determined the crystal structure at 2.5 Å resolution of the N-terminal region of Endo180, consisting of a ricin-like domain, a fibronectin type II (FN2) domain, and two C-type lectin (CTL) domains. The L-shaped arrangement of these domains creates a shallow trench spanning the FN2 and CTL1 domains, which was shown by mutagenesis to bind triple-helical and denatured collagen. Small-angle X-ray scattering showed that the L-shaped structure is maintained in solution at neutral and acidic pH, irrespective of calcium ion loading. Collagen binding was equally unaffected by acidic pH, suggesting that collagen release in endosomes is not regulated by changes within the Endo180 N-terminal region. PMID:26481812

  16. Rapid identification of lectin receptors and their possible function in sea urchin cell systems.

    PubMed

    Latham, V H; Herrera, S; Rostamiani, K; Chun, H H; Oppenheimer, S B

    1995-10-01

    An assay using lectin derivatized agarose beads to rapidly and inexpensively identify cell surface lectin receptors was recently described by Latham et al. (1995). In this earlier study, the assay was tested on large, early stage sea urchin embryo cells. In this study this assay was used to examine lectin receptors on small, later stage sea urchin embryo cells that are more typical of cells that most investigators deal with, to ascertain if cell size is a determining factor in the assay's validity. The results indicated that the assay is a valid method to identify lectin receptors on small as well as large cells. Twenty-three hour Strongylocentrotus purpuratus embryo cells strongly bound Triticum vulgaris, concanavalin A, Artocarpus integrifolia and Vicia villosa using both the agarose bead and fluorescence assays, while three other lectins, Ulex europaeus I, Lotus tetragonolobus and Lens culinaris did not strongly bind to the cells using these two assays. As in earlier studies agglutinability results did not correlate well with results using the two other assays. In all cases where lectin bead binding, fluorescent lectin binding or lectin-mediated agglutination occurred, specific sugars reduced the observed binding. The second part of this study examined the putative role of concanavilin A receptors in a specific cellular interaction: sperm-egg binding. Concanavalin A inhibited fertilization of dejellied sea urchin eggs when their vitelline layers were intact and to a lesser extent when their vitelline layers were removed. This effect was counteracted by alpha methyl glucose. The major differences between these studies and previous work is that here concanavalin A was washed out after incubation with eggs, making it more likely that results reflect binding to cell surface lectin receptors rather than toxicity. In addition, performing the experiments on eggs with or without vitelline layers provided information on the location of concanavalin A receptors that may

  17. Lectin-like Oxidized Low-Density Lipoprotein (LDL) Receptor (LOX-1): A Chameleon Receptor for Oxidized LDL.

    PubMed

    Zeya, Bushra; Arjuman, Albina; Chandra, Nimai Chand

    2016-08-16

    LOX-1, one of the main receptors for oxLDL, is found mainly on the surface of endothelial cells. It is a multifacet 52 kDa type II transmembrane protein that structurally belongs to the C-type lectin family. It exists with short intracellular N-terminal and long extracellular C-terminal hydrophilic domains separated by a hydrophobic domain of 26 amino acids. LOX-1 acts like a bifunctional receptor either showing pro-atherogenicity by activating the NFκB-mediated down signaling cascade for gene activation of pro-inflammatory molecules or playing an atheroprotective agent by receptor-mediated uptake of oxLDL in the presence of an anti-inflammatory molecule like IL-10. Mildly, moderately, and highly oxidized LDL show their characteristic features upon LOX-1 activation and its ligand binding indenture. The polymorphic LOX-1 genes are intensively associated with increased susceptibility to myocardial diseases. The splicing variant LOX IN dimerizes with the native form of LOX-1 and protects cells from damage by oxidized LDL. In the developing field of regenerating medicine, LOX-1 is a potential target for therapeutic intervention.

  18. Lectin-like Oxidized Low-Density Lipoprotein (LDL) Receptor (LOX-1): A Chameleon Receptor for Oxidized LDL.

    PubMed

    Zeya, Bushra; Arjuman, Albina; Chandra, Nimai Chand

    2016-08-16

    LOX-1, one of the main receptors for oxLDL, is found mainly on the surface of endothelial cells. It is a multifacet 52 kDa type II transmembrane protein that structurally belongs to the C-type lectin family. It exists with short intracellular N-terminal and long extracellular C-terminal hydrophilic domains separated by a hydrophobic domain of 26 amino acids. LOX-1 acts like a bifunctional receptor either showing pro-atherogenicity by activating the NFκB-mediated down signaling cascade for gene activation of pro-inflammatory molecules or playing an atheroprotective agent by receptor-mediated uptake of oxLDL in the presence of an anti-inflammatory molecule like IL-10. Mildly, moderately, and highly oxidized LDL show their characteristic features upon LOX-1 activation and its ligand binding indenture. The polymorphic LOX-1 genes are intensively associated with increased susceptibility to myocardial diseases. The splicing variant LOX IN dimerizes with the native form of LOX-1 and protects cells from damage by oxidized LDL. In the developing field of regenerating medicine, LOX-1 is a potential target for therapeutic intervention. PMID:27419271

  19. Genome-wide analysis of lectin receptor-like kinases in Populus

    DOE PAGESBeta

    Yang, Yongil; Labbé, Jessy; Muchero, Wellington; Yang, Xiaohan; Jawdy, Sara S.; Kennedy, Megan; Johnson, Jenifer; Sreedasyam, Avinash; Schmutz, Jeremy; Tuskan, Gerald A.; et al

    2016-09-01

    Receptor-like kinases (RLKs) belong to a large protein family with over 600 members in Arabidopsis and over 1000 in rice. Among RLKs, the lectin receptor-like kinases (LecRLKs) possess a characteristic extracellular carbohydrate-binding lectin domain and play important roles in plant development and innate immunity. In addition, there are 75 and 173 LecRLKs in Arabidopsis and rice, respectively. However, little is known about LecRLKs in perennial woody plants.

  20. Molecular characterization of the reniform nematode C-type lectin gene family reveals a likely role in mitigating environmental stresses during plant parasitism.

    PubMed

    Ganji, Satish; Jenkins, Johnie N; Wubben, Martin J

    2014-03-10

    The reniform nematode, Rotylenchulus reniformis, is a damaging semi-endoparasitic pathogen of more than 300 plant species. Transcriptome sequencing of R. reniformis parasitic females revealed an enrichment for sequences homologous to C-type lectins (CTLs), an evolutionarily ancient family of Ca(+2)-dependent carbohydrate-binding proteins that are involved in the innate immune response. To gain further insight as to the potential role of CTLs in facilitating plant parasitism by R. reniformis, we performed a comprehensive assessment of the CTL gene family. 5'- and 3'-RACE experiments identified a total of 11 R. reniformis CTL transcripts (Rr-ctl-1 through Rr-ctl-11) that ranged in length from 1083 to 1,194 bp and showed 93-99% identity with one another. An alignment of cDNA and genomic sequences revealed three introns with the first intron residing within the 5'-untranslated region. BLAST analyses showed the closest homologs belonging to the parasitic nematodes Heligmosomoides polygyrus and Heterodera glycines. Rr-ctl-1, -2, and -3 were expressed throughout the R. reniformis life cycle; whereas, the remaining Rr-ctl genes showed life stage-specific expression. Quantitative real time RT-PCR determined that Rr-ctl transcripts were 839-fold higher in sedentary female nematodes than the next most abundant life stage. Predicted Rr-CTL peptides ranged from 301 to 338 amino acids long, possessed an N-terminal signal peptide for secretion, and contained a conserved CLECT domain, including the mannose-binding motifs EPN and EPD and the conserved WND motif that is required for binding Ca(+2). In addition, Rr-CTL peptides harbored repeats of a novel 17-mer motif within their C-terminus that showed similarity to motifs associated with bacterial ice nucleation proteins. In situ hybridization of Rr-ctl transcripts within sedentary females showed specific accumulation within the hypodermis of the body regions exposed to the soil environment; those structures embedded within the

  1. Jackfruit (Artocarpus integrifolia) and the Agaricus mushroom lectin fit also to the so-called peanut receptor.

    PubMed

    Chatterjee, B P; Ahmed, H; Uhlenbruck, G; Janssen, E; Kolar, C; Seiler, F R

    1985-12-01

    The lectin from jackfruit (Artocarpus integrifolia) reacts with the peanut-specific lectin receptor represented by the T-disaccharide, which is also part of the Thomsen (= T)-Friedenreich antigen, namely O-beta-D-galactosyl-(1----3)-N-acetyl-D-galactosamine. The difference between the jackfruit lectin and peanut lectin has been shown to be mainly due to the further linkage of the T-disaccharide: Whereas the peanut lectin reacts with both anomeric forms, jackfruit lectin and the closely - with respect to its specificity - related Agaricus bisporus mushroom lectin react predominantly with the alpha-linked T-disaccharide, so that they cannot detect the lipid-linked T-disaccharide, as the peanut lectin does.

  2. The lipopolysaccharide-binding protein participating in hemocyte nodule formation in the silkworm Bombyx mori is a novel member of the C-type lectin superfamily with two different tandem carbohydrate-recognition domains.

    PubMed

    Koizumi, N; Imamura, M; Kadotani, T; Yaoi, K; Iwahana, H; Sato, R

    1999-01-25

    We recently isolated and characterized the lipopolysaccharide (LPS)-binding protein, BmLBP, from the larval hemolymph of the silkworm Bombyx mori. BmLBP is a pattern recognition molecule that recognizes the lipid A portion of LPS and participates in a cellular defense reaction. This paper describes the cDNA cloning of BmLBP. The deduced amino acid sequence of BmLBP revealed that BmLBP is a novel member of the C-type lectin superfamily with a unique structural feature that consists of two different carbohydrate-recognition domains in tandem, a short and a long form. PMID:9989592

  3. Lectin-Glycan Interaction Network-Based Identification of Host Receptors of Microbial Pathogenic Adhesins

    PubMed Central

    Ielasi, Francesco S.; Alioscha-Perez, Mitchel; Donohue, Dagmara; Claes, Sandra; Sahli, Hichem; Schols, Dominique

    2016-01-01

    ABSTRACT The first step in the infection of humans by microbial pathogens is their adherence to host tissue cells, which is frequently based on the binding of carbohydrate-binding proteins (lectin-like adhesins) to human cell receptors that expose glycans. In only a few cases have the human receptors of pathogenic adhesins been described. A novel strategy—based on the construction of a lectin-glycan interaction (LGI) network—to identify the potential human binding receptors for pathogenic adhesins with lectin activity was developed. The new approach is based on linking glycan array screening results of these adhesins to a human glycoprotein database via the construction of an LGI network. This strategy was used to detect human receptors for virulent Escherichia coli (FimH adhesin), and the fungal pathogens Candida albicans (Als1p and Als3p adhesins) and C. glabrata (Epa1, Epa6, and Epa7 adhesins), which cause candidiasis. This LGI network strategy allows the profiling of potential adhesin binding receptors in the host with prioritization, based on experimental binding data, of the most relevant interactions. New potential targets for the selected adhesins were predicted and experimentally confirmed. This methodology was also used to predict lectin interactions with envelope glycoproteins of human-pathogenic viruses. It was shown that this strategy was successful in revealing that the FimH adhesin has anti-HIV activity. PMID:27406561

  4. Receptors of garlic (Allium sativum) lectins and their role in insecticidal action.

    PubMed

    Upadhyay, Santosh K; Singh, Pradhyumna K

    2012-08-01

    Garlic (Allium sativum) lectins are promising candidate molecules for the protection against chewing (lepidopteran) as well as sap sucking (homopteran) insect pests. Molecular mechanism of toxicity and interaction of lectins with midgut receptor proteins has been described in many reports. Lectins show its effect right from sensory receptors of mouth parts by disrupting the membrane integrity and food detection ability. Subsequently, enter into the gut lumen and interact with midgut glycosylated proteins like alkaline phosphatase (ALP), aminopeptidase-N (APN), cadherin-like proteins, polycalins, sucrase, symbionin and others. These proteins play critical role in life cycle of insect directly or indirectly. Lectins interfere with the activity of these proteins and causes physiological disorders leading to the death of insects. Lectins further transported across the insect gut, accumulated in various body parts (like haemolymph and ovary) and interact with intracellular proteins like symbionin and cytochrome p450. Binding with cytochrome p450 (which involve in ecdysone synthesis) might interfere in the development of insects, which results in growth retardation and pre-mature death.

  5. Lectins with anti-HIV activity: a review.

    PubMed

    Akkouh, Ouafae; Ng, Tzi Bun; Singh, Senjam Sunil; Yin, Cuiming; Dan, Xiuli; Chan, Yau Sang; Pan, Wenliang; Cheung, Randy Chi Fai

    2015-01-01

    Lectins including flowering plant lectins, algal lectins, cyanobacterial lectins, actinomycete lectin, worm lectins, and the nonpeptidic lectin mimics pradimicins and benanomicins, exhibit anti-HIV activity. The anti-HIV plant lectins include Artocarpus heterophyllus (jacalin) lectin, concanavalin A, Galanthus nivalis (snowdrop) agglutinin-related lectins, Musa acuminata (banana) lectin, Myrianthus holstii lectin, Narcissus pseudonarcissus lectin, and Urtica diocia agglutinin. The anti-HIV algal lectins comprise Boodlea coacta lectin, Griffithsin, Oscillatoria agardhii agglutinin. The anti-HIV cyanobacterial lectins are cyanovirin-N, scytovirin, Microcystis viridis lectin, and microvirin. Actinohivin is an anti-HIV actinomycete lectin. The anti-HIV worm lectins include Chaetopterus variopedatus polychaete marine worm lectin, Serpula vermicularis sea worm lectin, and C-type lectin Mermaid from nematode (Laxus oneistus). The anti-HIV nonpeptidic lectin mimics comprise pradimicins and benanomicins. Their anti-HIV mechanisms are discussed. PMID:25569520

  6. Lectins with anti-HIV activity: a review.

    PubMed

    Akkouh, Ouafae; Ng, Tzi Bun; Singh, Senjam Sunil; Yin, Cuiming; Dan, Xiuli; Chan, Yau Sang; Pan, Wenliang; Cheung, Randy Chi Fai

    2015-01-01

    Lectins including flowering plant lectins, algal lectins, cyanobacterial lectins, actinomycete lectin, worm lectins, and the nonpeptidic lectin mimics pradimicins and benanomicins, exhibit anti-HIV activity. The anti-HIV plant lectins include Artocarpus heterophyllus (jacalin) lectin, concanavalin A, Galanthus nivalis (snowdrop) agglutinin-related lectins, Musa acuminata (banana) lectin, Myrianthus holstii lectin, Narcissus pseudonarcissus lectin, and Urtica diocia agglutinin. The anti-HIV algal lectins comprise Boodlea coacta lectin, Griffithsin, Oscillatoria agardhii agglutinin. The anti-HIV cyanobacterial lectins are cyanovirin-N, scytovirin, Microcystis viridis lectin, and microvirin. Actinohivin is an anti-HIV actinomycete lectin. The anti-HIV worm lectins include Chaetopterus variopedatus polychaete marine worm lectin, Serpula vermicularis sea worm lectin, and C-type lectin Mermaid from nematode (Laxus oneistus). The anti-HIV nonpeptidic lectin mimics comprise pradimicins and benanomicins. Their anti-HIV mechanisms are discussed.

  7. Epidermal growth factor receptors on PC12 cells: alteration of binding properties by lectins

    SciTech Connect

    Vale, R.D.; Shooter, E.M.

    1983-01-01

    The PC12 cell line displays cell surface receptors for both nerve growth factor (NGF) and epidermal growth factor (EGF). It has been previously shown that the lectin wheat germ agglutinin (WGA) alters the properties of NGF receptors on these cells. We now report that preincubations with either WGA or concanavalin A (Con A) decrease the binding of /sup 125/I-EGF to PC12 cells by greater than 50%. The inhibition of binding occurred at 37 degrees C and 4 degrees C and could be blocked or reversed by the addition of sugars which bind specifically to WGA or Con A. Scatchard analysis revealed that these lectins decreased binding primarily by lowering the affinity of the receptor and to a lesser extent by decreasing receptor number. Succinylation of Con A (sCon A) produced a derivative that was less effective than the native lectin in decreasing EGF binding; however, addition of an antibody against Con A restored the ability of sCon A to decrease binding. Similar to results obtained with /sup 125/I-NGF binding, WGA but not Con A was found to increase, by severalfold, the proportion of /sup 125/I-EGF binding that is resistant to solubilization by Triton X-100 detergent. A potential association of the EGF receptor with cytoskeletal elements is discussed which could account for such results.

  8. Structure and chromosomal assignment of the human lectin-like oxidized low-density-lipoprotein receptor-1 (LOX-1) gene.

    PubMed Central

    Aoyama, T; Sawamura, T; Furutani, Y; Matsuoka, R; Yoshida, M C; Fujiwara, H; Masaki, T

    1999-01-01

    We have reported the cDNA cloning of a modified low-density-lipoprotein (LDL) receptor, designated lectin-like oxidized LDL receptor-1 (LOX-1), which is postulated to be involved in endothelial dysfunction and the pathogenesis of atherosclerosis. Here, we determined the organization of the human LOX-1 gene, including the 5'-regulatory region. The 5'-regulatory region contained several potential cis-regulatory elements, such as GATA-2 binding element, c-ets-1 binding element, 12-O-tetradecanoylphorbol 13-acetate-responsive element and shear-stress-responsive elements, which may mediate the endothelium-specific and inducible expression of LOX-1. The major transcription-initiation site was found to be located 29 nucleotides downstream of the TATA box and 61 nucleotides upstream from the translation-initiation codon. The minor initiation site was found to be 5 bp downstream from the major site. Most of the promoter activity of the LOX-1 gene was ascribed to the region (-150 to -90) containing the GC and CAAT boxes. The coding sequence was divided into 6 exons by 5 introns. The first 3 exons corresponded to the different functional domains of the protein (cytoplasmic, transmembrane and neck domains), and the residual 3 exons encoded the carbohydrate-recognition domain similar to the case of other C-type lectin genes. The LOX-1 gene was a single-copy gene and assigned to the p12.3-p13.2 region of chromosome 12. Since the locus for a familial hypertension has been mapped to the overlapping region, LOX-1 might be the gene responsible for the hypertension. PMID:10085242

  9. Isolation of human beta-interferon receptor by wheat germ lectin affinity and immunosorbent column chromatographies

    SciTech Connect

    Zhang, Z.Q.; Fournier, A.; Tan, Y.H.

    1986-06-15

    Radioiodinated human beta-interferon-Ser 17 (Betaseron) was reversibly cross-linked to Daudi cells by dithiobis(succinimidylpropionate). The radioactive ligand was cross-linked to three macromolecules forming labeled complexes of apparent Mr values of 130,000, 220,000, and 320,000. Betaseron, human alpha-interferon, human interleukin 2 but not recombinant human gamma-interferon competed with the labeled ligand for binding to these putative receptor(s). Human leukocyte-produced gamma-interferon competed weakly with /sup 125/I-Betaseron for binding to Daudi cells. The Betaseron-receptor complex(es) was purified by passage through a wheat germ lectin column followed by chromatography on an anti-interferon immunosorbent column and semipreparative gel electrophoresis. The cross-linked ligand-receptor complex was shown to be highly purified by sodium dodecyl sulfate and acetic acid:urea:Triton X-100 polyacrylamide gel electrophoresis. It can be dissociated into the labeled Betaseron (Mr = 17,000) ligand and a receptor moiety which has an apparent molecular weight of 110,000. The chromatographic behavior of the ligand-receptor complex on wheat germ lectin column suggests that the receptor is a glycoprotein. The described procedure yielded about 1 microgram of Betaseron receptor from 10(10) Daudi cells, estimated to contain a maximum of about 15 micrograms of the receptor.

  10. The Mycobacterium tuberculosis cell-surface glycoprotein apa as a potential adhesin to colonize target cells via the innate immune system pulmonary C-type lectin surfactant protein A.

    PubMed

    Ragas, Aude; Roussel, Lucie; Puzo, Germain; Rivière, Michel

    2007-02-23

    Tuberculosis is still a major health problem, and understanding the mechanism by which Mycobacterium tuberculosis (Mtb) invades and colonizes its host target cells remains an important issue for the control of infection. The innate immune system C-type lectins (C-TLs), including the human pulmonary surfactant protein A (PSP-A), have been recently identified as determinant players in the early recognition of the invading pathogen and in mounting the host defense response. Although the antigenic lipoglycan mannosylated lipoarabinomannan is currently considered to be the major C-TL target on the mycobacterial surface, the recognition by some C-TLs of the only mycobacterial species composing the "Mtb complex" indicates that mannosylated lipoarabinomannan cannot account alone for this specificity. Thus, we searched for the mycobacterial molecules targeted by human PSP-A, focusing our attention on the Mtb surface glycoproteins. We developed an original functional proteomic approach based on a lectin blot assay using crude human bronchoalveolar lavage fluid as a source of physiological PSP-A. Combined with selective cell-surface protein extraction and mass spectrometry peptide mapping, this strategy allowed us to identify the Apa (alanine- and proline-rich antigenic) glycoprotein as new potential target for PSP-A. This result was supported by direct binding of PSP-A to purified Apa. Moreover, EDTA addition or deglycosylation of purified Apa samples completely abolished the interaction, demonstrating that the interaction is calcium- and mannose-dependent, as expected. Finally, we provide convincing evidence that Apa, formerly considered as mainly secreted, is associated with the cell wall for a sufficiently long time to aid in the attachment of PSP-A. Because, to date, Apa seems to be restricted to the Mtb complex strains, we propose that it may account for the selective recognition of those strains by PSP-A and other immune system C-TLs containing homologous functional

  11. Plant Lectin Can Target Receptors Containing Sialic Acid, Exemplified by Podoplanin, to Inhibit Transformed Cell Growth and Migration

    PubMed Central

    Shen, Yongquan; Acharya, Nimish K.; Han, Min; McNulty, Dean E.; Hasegawa, Hitoki; Hyodo, Toshinori; Senga, Takeshi; Geng, Jian-Guo; Kosciuk, Mary; Shin, Seung S.; Goydos, James S.; Temiakov, Dmitry; Nagele, Robert G.; Goldberg, Gary S.

    2012-01-01

    Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth. PMID:22844530

  12. Lectin-like oxidized low-density lipoprotein receptor (LOX-1) in sickle cell disease vasculopathy.

    PubMed

    Chen, Mingyi; Qiu, Hong; Lin, Xin; Nam, David; Ogbu-Nwobodo, Lucy; Archibald, Hannah; Joslin, Amelia; Wun, Ted; Sawamura, Tatsuya; Green, Ralph

    2016-09-01

    Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL. Increased expression of LOX-1 has been demonstrated in atherosclerotic lesions and diabetic vasculopathy. In this study, we investigate the expression of LOX-1 receptor in sickle cell disease (SCD) vasculopathy. Expression of LOX-1 in brain vascular endothelium is markedly increased and LOX-1 gene expression is upregulated in cultured human brain microvascular endothelial cells by incubation with SCD erythrocytes. Also, the level of circulating soluble LOX-1 concentration is elevated in the plasma of SCD patients. Increased LOX-1 expression in endothelial cells is potentially involved in the pathogenesis of SCD vasculopathy. Soluble LOX-1 concentration in SCD may provide a novel biomarker for risk stratification of sickle cell vascular complications. PMID:27519944

  13. An African swine fever virus ORF with similarity to C-type lectins is non-essential for growth in swine macrophages in vitro and for virus virulence in domestic swine.

    PubMed

    Neilan, J G; Borca, M V; Lu, Z; Kutish, G F; Kleiboeker, S B; Carrillo, C; Zsak, L; Rock, D L

    1999-10-01

    An African swine fever virus (ASFV) ORF, 8CR, with similarity to the C-type lectin family of adhesion proteins has been described in the pathogenic isolate Malawi Lil-20/1. The similarity of 8CR to cellular and poxvirus genes associated with cell adhesion, cell recognition and virus infectivity suggested that 8CR may be of significance to ASFV-host cell interactions. Sequence analysis of the 8CR ORF from additional pathogenic ASFV isolates demonstrated conservation among isolates from both pig and tick sources. Northern blot analysis demonstrated 8CR mRNA transcription late in the virus replication cycle. A Malawi Lil-20/1 8CR deletion mutant (delta8CR) was constructed to analyse 8CR function further. The growth characteristics in vitro of delta8CR in porcine macrophage cell cultures were identical to those observed for parental virus. In domestic swine, delta8CR exhibited an unaltered parental Malawi Lil-20/1 disease and virulence phenotype. Thus, although well conserved among pathogenic ASFV field isolates, 8CR is non-essential for growth in porcine macrophages in vitro and for virus virulence in domestic swine.

  14. RTB Lectin: a novel receptor-independent delivery system for lysosomal enzyme replacement therapies

    PubMed Central

    Acosta, Walter; Ayala, Jorge; Dolan, Maureen C.; Cramer, Carole L.

    2015-01-01

    Enzyme replacement therapies have revolutionized patient treatment for multiple rare lysosomal storage diseases but show limited effectiveness for addressing pathologies in “hard-to-treat” organs and tissues including brain and bone. Here we investigate the plant lectin RTB as a novel carrier for human lysosomal enzymes. RTB enters mammalian cells by multiple mechanisms including both adsorptive-mediated and receptor-mediated endocytosis, and thus provides access to a broader array of organs and cells. Fusion proteins comprised of RTB and human α-L-iduronidase, the corrective enzyme for Mucopolysaccharidosis type I, were produced using a tobacco-based expression system. Fusion products retained both lectin selectivity and enzyme activity, were efficiently endocytosed into human fibroblasts, and corrected the disease phenotype of mucopolysaccharidosis patient fibroblasts in vitro. RTB-mediated delivery was independent of high-mannose and mannose-6-phosphate receptors, which are exploited for delivery of currently approved lysosomal enzyme therapeutics. Thus, the RTB carrier may support distinct in vivo pharmacodynamics with potential to address hard-to-treat tissues. PMID:26382970

  15. Expression of lectin-like oxidized LDL receptor-1 in smooth muscle cells after vascular injury

    SciTech Connect

    Eto, Hideyuki; Miyata, Masaaki . E-mail: miyatam@m3.kufm.kagoshima-u.ac.jp; Kume, Noriaki; Minami, Manabu; Itabe, Hiroyuki; Orihara, Koji; Hamasaki, Shuichi; Biro, Sadatoshi; Otsuji, Yutaka; Kita, Toru; Tei, Chuwa

    2006-03-10

    Lectin-like oxidized LDL receptor-1 (LOX-1) is an oxidized LDL receptor, and its role in restenosis after angioplasty remains unknown. We used a balloon-injury model of rabbit aorta, and reverse transcription-polymerase chain reaction revealed that LOX-1 mRNA expression was modest in the non-injured aorta, reached a peak level 2 days after injury, and remained elevated until 24 weeks after injury. Immunohistochemistry and in situ hybridization showed that LOX-1 was not detected in the media of non-injured aorta but expressed in both medial and neointimal smooth muscle cells (SMC) at 2 and 24 weeks after injury. Low concentrations of ox-LDL (10 {mu}g/mL) stimulated the cultured SMC proliferation, which was inhibited by antisense oligonucleotides of LOX-1 mRNA. Double immunofluorescense staining showed the colocalization of LOX-1 and proliferating cell nuclear antigen in human restenotic lesion. These results suggest that LOX-1 mediates ox-LDL-induced SMC proliferation and plays a role in neointimal formation after vascular injury.

  16. Specific Endocytosis Blockade of Trypanosoma cruzi Exposed to a Poly-LAcNAc Binding Lectin Suggests that Lectin-Sugar Interactions Participate to Receptor-Mediated Endocytosis

    PubMed Central

    Brosson, Sébastien; Fontaine, Frédéric; Vermeersch, Marjorie; Perez-Morga, David; Pays, Etienne; Bousbata, Sabrina; Salmon, Didier

    2016-01-01

    Trypanosoma cruzi is a protozoan parasite transmitted by a triatomine insect, and causing human Chagas disease in South America. This parasite undergoes a complex life cycle alternating between non-proliferative and dividing forms. Owing to their high energy requirement, replicative epimastigotes of the insect midgut display high endocytic activity. This activity is mainly restricted to the cytostome, by which the cargo is taken up and sorted through the endosomal vesicular network to be delivered to reservosomes, the final lysosomal-like compartments. In African trypanosomes tomato lectin (TL) and ricin, respectively specific to poly-N-acetyllactosamine (poly-LacNAc) and β-D-galactose, allowed the identification of giant chains of poly-LacNAc in N-glycoproteins of the endocytic pathway. We show that in T. cruzi epimastigote forms also, glycoproteins of the endocytic pathway are characterized by the presence of N-linked glycans binding to both ricin and TL. Affinity chromatography using both TL and Griffonia simplicifolia lectin II (GSLII), specific to non-reducing terminal residue of N-acetylglucosamine (GlcNAc), led to an enrichment of glycoproteins of the trypanosomal endocytic pathway. Incubation of live parasites with TL, which selectively bound to the cytostome/cytopharynx, specifically inhibited endocytosis of transferrin (Tf) but not dextran, a marker of fluid endocytosis. Taken together, our data suggest that N-glycan modification of endocytic components plays a crucial role in receptor-mediated endocytosis of T. cruzi. PMID:27685262

  17. Structure-Function Analyses of a Staphylococcus epidermidis Autoinducing Peptide Reveals Motifs Critical for AgrC-type Receptor Modulation.

    PubMed

    Yang, Tian; Tal-Gan, Yftah; Paharik, Alexandra E; Horswill, Alexander R; Blackwell, Helen E

    2016-07-15

    Staphylococcus epidermidis is frequently implicated in human infections associated with indwelling medical devices due to its ubiquity in the skin flora and formation of robust biofilms. The accessory gene regulator (agr) quorum sensing (QS) system plays a prominent role in the establishment of biofilms and infection by this bacterium. Agr activation is mediated by the binding of a peptide signal (or autoinducing peptide, AIP) to its cognate AgrC receptor. Many questions remain about the role of QS in S. epidermidis infections, as well as in mixed-microbial populations on a host, and chemical modulators of its agr system could provide novel insights into this signaling network. The AIP ligand provides an initial scaffold for the development of such probes; however, the structure-activity relationships (SARs) for activation of S. epidermidis AgrC receptors by AIPs are largely unknown. Herein, we report the first SAR analyses of an S. epidermidis AIP by performing systematic alanine and d-amino acid scans of the S. epidermidis AIP-I. On the basis of these results, we designed and identified potent, pan-group inhibitors of the AgrC receptors in the three S. epidermidis agr groups, as well as a set of AIP-I analogs capable of selective AgrC inhibition in either specific S. epidermidis agr groups or in another common staphylococcal species, S. aureus. In addition, we uncovered a non-native peptide agonist of AgrC-I that can strongly inhibit S. epidermidis biofilm growth. Together, these synthetic analogs represent new and readily accessible probes for investigating the roles of QS in S. epidermidis colonization and infections.

  18. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer.

    PubMed

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-03-22

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  19. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer

    PubMed Central

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-01-01

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  20. Lectin Receptor Kinases Participate in Protein-Protein Interactions to Mediate Plasma Membrane-Cell Wall Adhesions in Arabidopsis1

    PubMed Central

    Gouget, Anne; Senchou, Virginie; Govers, Francine; Sanson, Arnaud; Barre, Annick; Rougé, Pierre; Pont-Lezica, Rafael; Canut, Hervé

    2006-01-01

    Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown. Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis (Arabidopsis thaliana), are disrupted by the RGD (arginine-glycine-aspartic acid) tripeptide sequence, a characteristic cell adhesion motif in mammals. In planta induced-O (IPI-O) is an RGD-containing protein from the plant pathogen Phytophthora infestans that can disrupt cell wall-plasma membrane adhesions through its RGD motif. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis. Moreover, the two peptides also disrupted cell wall-plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g60300, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces. PMID:16361528

  1. Candida glabrata binds to glycosylated and lectinic receptors on the coronary endothelial luminal membrane and inhibits flow sense and cardiac responses to agonists.

    PubMed

    Torres-Tirado, David; Knabb, Maureen; Castaño, Irene; Patrón-Soberano, Araceli; De Las Peñas, Alejandro; Rubio, Rafael

    2016-01-01

    Candida glabrata (CG) is an opportunistic fungal pathogen that initiates infection by binding to host cells via specific lectin-like adhesin proteins. We have previously shown the importance of lectin-oligosaccharide binding in cardiac responses to flow and agonists. Because of the lectinic-oligosaccharide nature of CG binding, we tested the ability of CG to alter the agonist- and flow-induced changes in cardiac function in isolated perfused guinea pig hearts. Both transmission and scanning electron microscopy showed strong attachment of CG to the coronary endothelium, even after extensive washing. CG shifted the coronary flow vs. auricular-ventricular (AV) delay relationship upward, indicating that greater flow was required to achieve the same AV delay. This effect was completely reversed with mannose, partially reversed with galactose and N-acetylgalactosamine, but hyaluronan had no effect. Western blot analysis was used to determine binding of CG to isolated coronary endothelial luminal membrane (CELM) receptors, and the results indicate that flow-sensitive CELM receptors, ANG II type I, α-adrenergic 1A receptor, endothelin-2, and VCAM-1 bind to CG. In addition, CG inhibited agonist-induced effects of bradykinin, angiotensin, and phenylephrine on AV delay, coronary perfusion pressure, and left ventricular pressure. Mannose reversed the inhibitory effects of CG on the agonist responses. These results suggest that CG directly binds to flow-sensitive CELM receptors via lectinic-oligosaccharide interactions with mannose and disrupts the lectin-oligosaccharide binding necessary for flow-induced cardiac responses.

  2. Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation

    SciTech Connect

    Lee, Ha Young; Kim, Sang Doo; Baek, Suk-Hwan; Choi, Joon Hyuk; Cho, Kyung-Hyun; Zabel, Brian A.; Bae, Yoe-Sik

    2013-03-29

    Highlights: ► SAA induced macrophage foam cell formation. ► SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ► SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-κB signaling. ► HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ► The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-κB (NF-κB). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.

  3. Complete structure of the cell surface polysaccharide of Streptococcus oralis ATCC 10557: A receptor for lectin-mediated interbacterial adherence

    SciTech Connect

    Abeygunawardana, C.; Bush, C.A. ); Cisar, J.O. )

    1991-07-02

    Lectin-carbohydrate binding is known to play an important role in a number of different cell-cell interactions including those between certain species of oral streptococci and actinomyces that colonize teeth. The cell wall polysaccharides of Streptococcus oralis ATCC 10557, S. oralis 34, and Streptococcus mitis J22, although not identical antigenically, each function as a receptor molecule for the galactose and N-acetylgalactosamine reactive fimbrial lectins of Actinomyces viscosus and Actinomyces naeslundii. Carbohydrate analysis of the receptor polysaccharide isolated from S. oralis ATCC 10557 shows galactose (3 mol), glucose (1 mol), GalNAc (1 mol), and rhamnose (1 mol). {sup 1}H NMR spectra of the polysaccharide show that is partially O-acetylated. Analysis of the {sup 1}H NMR spectrum of the de-O-acetylated polysaccharide shows that it is composed of repeating subunits containing six monosaccharides and that the subunits are joined by a phosphodiester linkage. The {sup 1}H and {sup 13}C NMR spectra were completely assigned by two-dimensional homonuclear correlation methods and by {sup 1}H-detected heteronuclear multiple-quantum correlation ({sup 1}H({sup 13}C)HMQC). The complete {sup 1}H and {sup 13}C assignment of the native polysaccharide was carried out by the same techniques augmented by a {sup 13}C-coupled hybrid HMQC-COSY method, which is shown to be especially useful for carbohydrates in which strong coupling and overlapping peaks in the {sup 1}H spectrum pose difficulties.

  4. L-type lectin receptor kinases in Nicotiana benthamiana and tomato and their role in Phytophthora resistance

    PubMed Central

    Wang, Yan; Weide, Rob; Govers, Francine; Bouwmeester, Klaas

    2015-01-01

    Membrane-bound receptors play crucial roles as sentinels of plant immunity against a large variety of invading microbes. One class of receptors known to be involved in self/non-self-surveillance and plant resistance comprises the L-type lectin receptor kinases (LecRKs). Previously, we reported that several Arabidopsis LecRKs play a role in resistance to Phytophthora pathogens. In this study, we determined whether homologues of these LecRKs from the Solanaceous plants Nicotiana benthamiana and tomato (Solanum lycopersicum) play similar roles in defence against Phytophthora. In genome-wide screenings, a total of 38 (Nb)LecRKs were identified in N. benthamiana and 22 (Sl)LecRKs in tomato, each consisting of both a lectin and a kinase domain. Phylogenetic analysis revealed that, in contrast to Arabidopsis, which has a LecRK family comprising nine clades, Solanaceous species have just five of these nine clades (i.e. IV, VI, VII, VIII, and IX), plus four additional clades that lack Arabidopsis homologues. Several of the Solanaceous LecRKs were selected for functional analysis using virus-induced gene silencing. Infection assays with Phytophthora capsici and Phytophthora infestans on LecRK-silenced plants revealed that N. benthamiana and tomato homologues in clade IX play a role in Phytophthora resistance similar to the two Arabidopsis LecRKs in this clade, suggesting conserved functions of clade IX LecRKs across different plant families. This study provides a first insight into the diversity of Solanaceous LecRKs and their role in plant immunity, and shows the potential of LecRKs for Phytophthora resistance breeding. PMID:26248665

  5. L-type lectin receptor kinases in Nicotiana benthamiana and tomato and their role in Phytophthora resistance.

    PubMed

    Wang, Yan; Weide, Rob; Govers, Francine; Bouwmeester, Klaas

    2015-11-01

    Membrane-bound receptors play crucial roles as sentinels of plant immunity against a large variety of invading microbes. One class of receptors known to be involved in self/non-self-surveillance and plant resistance comprises the L-type lectin receptor kinases (LecRKs). Previously, we reported that several Arabidopsis LecRKs play a role in resistance to Phytophthora pathogens. In this study, we determined whether homologues of these LecRKs from the Solanaceous plants Nicotiana benthamiana and tomato (Solanum lycopersicum) play similar roles in defence against Phytophthora. In genome-wide screenings, a total of 38 (Nb)LecRKs were identified in N. benthamiana and 22 (Sl)LecRKs in tomato, each consisting of both a lectin and a kinase domain. Phylogenetic analysis revealed that, in contrast to Arabidopsis, which has a LecRK family comprising nine clades, Solanaceous species have just five of these nine clades (i.e. IV, VI, VII, VIII, and IX), plus four additional clades that lack Arabidopsis homologues. Several of the Solanaceous LecRKs were selected for functional analysis using virus-induced gene silencing. Infection assays with Phytophthora capsici and Phytophthora infestans on LecRK-silenced plants revealed that N. benthamiana and tomato homologues in clade IX play a role in Phytophthora resistance similar to the two Arabidopsis LecRKs in this clade, suggesting conserved functions of clade IX LecRKs across different plant families. This study provides a first insight into the diversity of Solanaceous LecRKs and their role in plant immunity, and shows the potential of LecRKs for Phytophthora resistance breeding.

  6. L-type lectin receptor kinases in Nicotiana benthamiana and tomato and their role in Phytophthora resistance.

    PubMed

    Wang, Yan; Weide, Rob; Govers, Francine; Bouwmeester, Klaas

    2015-11-01

    Membrane-bound receptors play crucial roles as sentinels of plant immunity against a large variety of invading microbes. One class of receptors known to be involved in self/non-self-surveillance and plant resistance comprises the L-type lectin receptor kinases (LecRKs). Previously, we reported that several Arabidopsis LecRKs play a role in resistance to Phytophthora pathogens. In this study, we determined whether homologues of these LecRKs from the Solanaceous plants Nicotiana benthamiana and tomato (Solanum lycopersicum) play similar roles in defence against Phytophthora. In genome-wide screenings, a total of 38 (Nb)LecRKs were identified in N. benthamiana and 22 (Sl)LecRKs in tomato, each consisting of both a lectin and a kinase domain. Phylogenetic analysis revealed that, in contrast to Arabidopsis, which has a LecRK family comprising nine clades, Solanaceous species have just five of these nine clades (i.e. IV, VI, VII, VIII, and IX), plus four additional clades that lack Arabidopsis homologues. Several of the Solanaceous LecRKs were selected for functional analysis using virus-induced gene silencing. Infection assays with Phytophthora capsici and Phytophthora infestans on LecRK-silenced plants revealed that N. benthamiana and tomato homologues in clade IX play a role in Phytophthora resistance similar to the two Arabidopsis LecRKs in this clade, suggesting conserved functions of clade IX LecRKs across different plant families. This study provides a first insight into the diversity of Solanaceous LecRKs and their role in plant immunity, and shows the potential of LecRKs for Phytophthora resistance breeding. PMID:26248665

  7. Enhancement of angiogenesis by a 27 kDa lectin from perivitelline fluid of horseshoe crab embryos through upregulation of VEGF and its receptor.

    PubMed

    Surekha, K L; Waghchoude, Meenal; Ghaskadbi, Surendra

    2013-01-25

    Angiogenesis, the expansion of a capillary network, is implicated in several pathological conditions. Drug-based inhibition of angiogenesis is being explored as therapy. Conversely, therapeutic angiogenesis contributes to control conditions such as ischemia. Here we report pro-angiogenic activity of perivitelline fluid (PVF) from Indian horseshoe crab embryos and one of its purified fractions, a 27 kDa lectin, using the chick embryonic chorioallantoic membrane assay. Enhancement in number and diameter of blood vessels after treatment with PVF and lectin suggested their pro-angiogenic effect. Quantitative RT-PCR showed that this effect is mediated through modulation of expression of VEGF and VEGFR-2/kinase domain receptor genes.

  8. Possible involvement of central C-type natriuretic polypeptide receptor on water intake in spontaneously hypertensive rats, but not in normotensive Wistar-Kyoto rats.

    PubMed

    Shibata, K; Makino, I; Goto, E; Katsuragi, T; Furukawa, T

    1999-12-01

    The present study was designed to examine the possible role of brain C-type natriuretic polypeptide receptor (GC-B) in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY). The level of GC-B mRNA in various regions of the brain in both SHR and WKY was examined in the present study. The GC-B mRNA was unevenly distributed in rat brain, the transcript being expressed predominantly in the hypothalamus and cerebellum but comparatively at low level in the striatum and septum. However, the level in the septum was 3-fold higher in SHR than than in age-matched WKY, while no differences were observed in other regions of the brain. Intracerebroventricular administration of antisense oligonucleotide to GC-B mRNA inhibits the night-time water intake in SHR, but not in WKY. However, the daily food intake was not significantly altered by the injection of antisense oligonucleotide in both strains. These results demonstrate that the brain GC-B mRNA, particularly in septum, is increased in SHR and this increase may be closely related to the regulation of water-drinking behaviour in SHR.

  9. A new lectin in red kidney beans called PvFRIL stimulates proliferation of NIH 3T3 cells expressing the Flt3 receptor.

    PubMed

    Moore, J G; Fuchs, C A; Hata, Y S; Hicklin, D J; Colucci, G; Chrispeels, M J; Feldman, M

    2000-07-26

    A new legume lectin has been identified by its ability to specifically stimulate proliferation of NIH 3T3 fibroblasts expressing the Flt3 tyrosine kinase receptor. The lectin was isolated from conditioned medium harvested from human peripheral blood mononuclear cells activated to secrete cytokines by a crude red kidney bean extract containing phytohemagglutinin (PHA). Untransfected 3T3 cells and 3T3 cells transfected with the related Fms tyrosine kinase receptor do not respond to this lectin, which we called PvFRIL (Phaseolus vulgaris Flt3 receptor-interacting lectin). When tested on cord blood mononuclear cells enriched for Flt3-expressing progenitors, purified PvFRIL fractions maintained a small population of cells that continued to express CD34 after 2 weeks in suspension cultures containing IL3. These cultures did not show the effects of IL3's strong induction of proliferation and differentiation (high cell number and exhausted medium); instead, low cell number at the end of the culture period resulted in persistence of cells in the context of cell death. These observations led to the hypothesis that PvFRIL acts in a dominant manner to preserve progenitor viability and prevent proliferation and differentiation.

  10. A new lectin in red kidney beans called PvFRIL stimulates proliferation of NIH 3T3 cells expressing the Flt3 receptor.

    PubMed

    Moore, J G; Fuchs, C A; Hata, Y S; Hicklin, D J; Colucci, G; Chrispeels, M J; Feldman, M

    2000-07-26

    A new legume lectin has been identified by its ability to specifically stimulate proliferation of NIH 3T3 fibroblasts expressing the Flt3 tyrosine kinase receptor. The lectin was isolated from conditioned medium harvested from human peripheral blood mononuclear cells activated to secrete cytokines by a crude red kidney bean extract containing phytohemagglutinin (PHA). Untransfected 3T3 cells and 3T3 cells transfected with the related Fms tyrosine kinase receptor do not respond to this lectin, which we called PvFRIL (Phaseolus vulgaris Flt3 receptor-interacting lectin). When tested on cord blood mononuclear cells enriched for Flt3-expressing progenitors, purified PvFRIL fractions maintained a small population of cells that continued to express CD34 after 2 weeks in suspension cultures containing IL3. These cultures did not show the effects of IL3's strong induction of proliferation and differentiation (high cell number and exhausted medium); instead, low cell number at the end of the culture period resulted in persistence of cells in the context of cell death. These observations led to the hypothesis that PvFRIL acts in a dominant manner to preserve progenitor viability and prevent proliferation and differentiation. PMID:10913819

  11. The effect of short-wavelength ultraviolet light on antigens, lectin receptors and the ultrastructure of Crithidia fasciculata.

    PubMed

    Santos, M A; Barros, A M; Andrade, P P; Padovan, I P

    1989-01-01

    Crithidia fasciculata is an important trypanosomatid parasite commonly affecting insects and is used extensively as a model for the study of the biochemistry, ultrastructure and organization of the kDNA network of trypanosomatids. The present study describes the evolution of UV-induced morphological changes detectable by transmission electron microscopy in Crithidia fasciculata. Although only rare and minor changes in kinetoplast DNA were demonstrable 7 h after UV irradiation, alterations of this organelle were present in almost all flagellates observed 24 h and 48 h after irradiation. Other cell structures were apparently undamaged. Ultrastructural changes in kDNA did not correspond to changes in antigenicity of protein bands in western blotting against serum from Chagas' disease patients or in the presence of 3 different lectin receptors on the surface of the parasite. PMID:2553178

  12. Toll-like receptors (TLRs) and mannan-binding lectin (MBL): on constant alert in a hostile environment.

    PubMed

    Bergman, Ingrid-Maria

    2011-05-01

    In the beginning were neither B cells nor T cells nor antibodies, but innate immune defense alone. The primary functional theme of innate immunity is the distinction between self and non-self, which is maintained by a vast number of cellular and subcellular components. In this context, the immense importance of the Toll-like receptors (TLRs) is well established. Positive (Darwinian) selection seems to be acting on the ligand-binding domains of these molecules, suggesting a selection pattern similar to that previously observed in the MHC proteins. In sharp contrast to TLRs, the biological significance of mannan-binding lectin (MBL) is controversial, and, concerning humans, it has been suggested that low concentration of MBL in serum represents a selective advantage. In this mini-review, based on a doctoral thesis, evolutionary aspects of TLRs and MBL are discussed. PMID:21323627

  13. A Lectin-Like Receptor is Involved in Invasion of Erythrocytes by Plasmodium falciparum

    NASA Astrophysics Data System (ADS)

    Jungery, M.; Pasvol, G.; Newbold, C. I.; Weatherall, D. J.

    1983-02-01

    Glycophorin both in solution and inserted into liposomes blocks invasion of erythrocytes by the malaria parasite Plasmodium falciparum. Furthermore, one sugar, N-acetyl-D-glucosamine (GlcNAc), completely blocks invasion of the erythrocyte by this parasite. GlcNAc coupled to bovine serum albumin to prevent the sugar entering infected erythrocytes was at least 100,000 times more effective than GlcNAc alone. Bovine serum albumin coupled to lactose or bovine serum albumin alone had no effect on invasion. These results suggest that the binding of P. falciparum to erythrocytes is lectin-like and is determined by carbohydrates on glycophorin.

  14. Identification of the lectin-like receptor for oxidized low-density lipoprotein in human macrophages and its potential role as a scavenger receptor.

    PubMed Central

    Yoshida, H; Kondratenko, N; Green, S; Steinberg, D; Quehenberger, O

    1998-01-01

    A new receptor for oxidized low-density lipoprotein (LDL), lectin-like oxidized LDL receptor-1 (LOX-1), has recently been cloned from bovine endothelial cells and human lung. A limited tissue-distribution study suggested that the protein was mainly produced by the vascular endothelium. In the present study we demonstrate that LOX-1 is also expressed in macrophages, where it may function as a scavenger receptor. LOX-1 was not detected in undifferentiated THP-1 cells or in freshly isolated human blood monocytes. However, mature human monocyte-derived macrophages and differentiated THP-1 cells showed high levels of LOX-1 transcripts. Consistent with these results, immunofluorescence staining and FACS analysis demonstrated that LOX-1 protein is expressed on the plasma membrane of macrophages. Western-blot analysis of membranes from macrophages (but not those from monocytes) identified a single band, with an apparent molecular mass of about 40 kDa, that displayed oxidized LDL-binding activity. These results suggest that differentiation induces the expression of LOX-1 in macrophages, where it may play a role as a scavenger receptor and/or a receptor for oxidized LDL. PMID:9693095

  15. Diversity of lectins in Macrobrachium rosenbergii and their expression patterns under spiroplasma MR-1008 stimulation.

    PubMed

    Zhu, Huanxi; Du, Jie; Hui, Kai-Min; Liu, Peng; Chen, Jing; Xiu, Yunji; Yao, Wei; Wu, Ting; Meng, Qingguo; Gu, Wei; Ren, Qian; Wang, Wen

    2013-08-01

    Lectins play important roles in crustacean innate immunity through recognition of foreign pathogens. In this study, 20 lectins including C-type lectins [dual-carbohydrate recognition domain (CRD) type and single-CRD type], L-type lectin, and lectin with low-density lipoprotein class A (LDLa) domain were identified from the freshwater prawn Macrobrachium rosenbergii. The tissue distribution and expression patterns of these lectins under spiroplasma strain MR-1008 challenge were investigated. Most of the lectins were found to be mainly distributed in the hepatopancreas. Lectin5, Lectin14, Lectin17, and Lectin18 exhibited the highest expression level in the hemocytes, nerve, intestine, and heart, respectively. MrLec1 to MrLec6 (dual-CRD lectins) in the hepatopancreas were up-regulated by spiroplasma challenge. Single-CRD lectins reached the highest level at 72 h after spiroplasma challenge. Lectin9 and Lectin15 both belong to L-type lectins. At post-spiroplasma challenge, Lectin9 expression was up-regulated, whereas Lectin15 expression was down-regulated. Lectin11 with LDLa domain showed the highest level after 12 h Lectin18 and Lectin20, namely, CD209, were also up-regulated by spiroplasma challenge. Lectin14, a C-type lectin, quickly reached the highest level after 2 h Lectin16 showed the highest level after 72 h Lectin5 reached the highest level in cultured hemocytes after 6 h Lectin17 in the intestine and Lectin14 in the nerve were slightly up-regulated after 6 and 2 h, respectively. Our research results indicate that lectins may play important roles in early or late immune responses against spiroplasma challenge.

  16. Identification of a porcine DC-SIGN-related C-type lectin, porcine CLEC4G (LSECtin), and its order of intron removal during splicing: comparative genomic analyses of the cluster of genes CD23/CLEC4G/DC-SIGN among mammalian species.

    PubMed

    Huang, Y W; Meng, X J

    2009-06-01

    Human CLEC4G (previously named LSECtin), DC-SIGN, and L-SIGN are three important C-type lectins capable of mediating viral and bacterial pathogen recognitions. These three genes, together with CD23, form a lectin gene cluster at chromosome 19p13.3. In this study, we have experimentally identified the cDNA and the gene encoding porcine CLEC4G (pCLEC4G). Full-length pCLEC4G cDNA encodes a type II transmembrane protein of 290 amino acids. pCLEC4G gene has the same gene structure as the human and the predicted bovine, canis, mouse and rat CLEC4G genes with nine exons. A multi-species-conserved site at the extreme 3'-untranslated region of CLEC4G mRNAs was predicted to be targeted by microRNA miR-350 in domesticated animals and by miR-145 in primates, respectively. We detected pCLEC4G mRNA expression in liver, lymph node and spleen tissues. We also identified a series of sequential intermediate products of pCLEC4G pre-mRNA during splicing from pig liver. The previously unidentified porcine CD23 cDNA containing the complete coding region was subsequently cloned and found to express in spleen, thymus and lymph node. Furthermore, we compared the chromosomal regions syntenic to the human cluster of genes CD23/CLEC4G/DC-SIGN/L-SIGN in representative mammalian species including primates, domesticated animal, rodents and opossum. The L-SIGN homologues do not exist in non-primates mammals. The evolutionary processes of the gene cluster, from marsupials to primates, were proposed based upon their genomic structures and phylogenetic relationships.

  17. Binding of insecticidal lectin Colocasia esculenta tuber agglutinin (CEA) to midgut receptors of Bemisia tabaci and Lipaphis erysimi provides clues to its insecticidal potential.

    PubMed

    Roy, Amit; Gupta, Sumanti; Hess, Daniel; Das, Kali Pada; Das, Sampa

    2014-07-01

    The insecticidal potential of Galanthus nivalis agglutinin-related lectins against hemipterans has been experimentally proven. However, the basis behind the toxicity of these lectins against hemipterans remains elusive. The present study elucidates the molecular basis behind insecticidal efficacy of Colocasia esculenta tuber agglutinin (CEA) against Bemisia tabaci and Lipaphis erysimi. Confocal microscopic analyses highlighted the binding of 25 kDa stable homodimeric lectin to insect midgut. Ligand blots followed by LC MS/MS analyses identified binding partners of CEA as vacuolar ATP synthase and sarcoplasmic endoplasmic reticulum type Ca(2+) ATPase from B. tabaci, and ATP synthase, heat shock protein 70 and clathrin heavy chain assembly protein from L. erysimi. Internalization of CEA into hemolymph was confirmed by Western blotting. Glycoprotein nature of the receptors was identified through glycospecific staining. Deglycosylation assay indicated the interaction of CEA with its receptors to be probably glycan mediated. Surface plasmon resonance analysis revealed the interaction kinetics between ATP synthase of B. tabaci with CEA. Pathway prediction study based on Drosophila homologs suggested the interaction of CEA with insect receptors that probably led to disruption of cellular processes causing growth retardation and loss of fecundity of target insects. Thus, the present findings strengthen our current understanding of the entomotoxic potentiality of CEA, which will facilitate its future biotechnological applications.

  18. Binding of insecticidal lectin Colocasia esculenta tuber agglutinin (CEA) to midgut receptors of Bemisia tabaci and Lipaphis erysimi provides clues to its insecticidal potential.

    PubMed

    Roy, Amit; Gupta, Sumanti; Hess, Daniel; Das, Kali Pada; Das, Sampa

    2014-07-01

    The insecticidal potential of Galanthus nivalis agglutinin-related lectins against hemipterans has been experimentally proven. However, the basis behind the toxicity of these lectins against hemipterans remains elusive. The present study elucidates the molecular basis behind insecticidal efficacy of Colocasia esculenta tuber agglutinin (CEA) against Bemisia tabaci and Lipaphis erysimi. Confocal microscopic analyses highlighted the binding of 25 kDa stable homodimeric lectin to insect midgut. Ligand blots followed by LC MS/MS analyses identified binding partners of CEA as vacuolar ATP synthase and sarcoplasmic endoplasmic reticulum type Ca(2+) ATPase from B. tabaci, and ATP synthase, heat shock protein 70 and clathrin heavy chain assembly protein from L. erysimi. Internalization of CEA into hemolymph was confirmed by Western blotting. Glycoprotein nature of the receptors was identified through glycospecific staining. Deglycosylation assay indicated the interaction of CEA with its receptors to be probably glycan mediated. Surface plasmon resonance analysis revealed the interaction kinetics between ATP synthase of B. tabaci with CEA. Pathway prediction study based on Drosophila homologs suggested the interaction of CEA with insect receptors that probably led to disruption of cellular processes causing growth retardation and loss of fecundity of target insects. Thus, the present findings strengthen our current understanding of the entomotoxic potentiality of CEA, which will facilitate its future biotechnological applications. PMID:24753494

  19. Chronic Aerobic Exercise Decreases Lectin-Like Low Density Lipoprotein (LOX-1) Receptor Expression in Heart of Diabetic Rat

    PubMed Central

    Riahi, Simin; Mohammadi, Mohammad Taghi; Sobhani, Vahid; Ababzadeh, Shima

    2016-01-01

    Background: Overexpression of lectin-like low density lipoprotein (LOX-1) receptor plays an important role in hyperglycemia-induced vascular complications such as atherosclerosis. Based on the beneficial effects of exercise on preventing cardiovascular complications of diabetes, we aimed to examine the protective effects of aerobic exercise on expression of LOX-1 receptor and production of free radicals in the heart of diabetic rats. Methods: Four groups of rats were used: (n = 5 per group): sedentary normal, trained normal, sedentary diabetes and trained diabetes. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg/kg). The exercise protocol was consisted of swimming 30 min/day, 5 days/week for eight weeks. Plasma glucose was evaluated at initiation, weeks 4 and 8 of experiment. At the end of experiment, rats were sacrificed and the heart was removed for determination of nitrate, malondialdehyde, and LOX-1 gene expression. Results: In normal non-diabetic rats, the blood glucose level was <150 mg/dl; however, the induction of diabetes resulted in levels more than >400 mg/dl. Gene expression of LOX-1 was increased in the heart of diabetic rats. Exercise reduced the gene expression of this protein in diabetic states without reducing the blood glucose. Finally, swimming exercise decreased the malondialdehyde and nitrate levels in heart tissue both in control and diabetic rats. Conclusion: Swimming exercise reduces heart expression of the LOX-1 receptor in accompany with reduction of free radicals production. Since these parameters are important in generation of diabetic complications, swimming exercise is a good candidate for reducing these complications. PMID:26432573

  20. Expression of lectin-like oxidized low density lipoprotein receptor-1 in human and murine macrophages: upregulated expression by TNF-alpha.

    PubMed

    Moriwaki, H; Kume, N; Kataoka, H; Murase, T; Nishi, E; Sawamura, T; Masaki, T; Kita, T

    1998-11-27

    Uptake of oxidized low density lipoprotein (Ox-LDL) and subsequent foam cell transformation have been implicated in early atherogenesis. Although multiple molecules, including class A and B scavenger receptors, have been identified as Ox-LDL receptors, additional receptors may also be involved in this process. Here, we provide evidence that lectin-like Ox-LDL receptor-1 (LOX-1), a novel Ox-LDL receptor initially identified in vascular endothelial cells, is also expressed in macrophages in humans and mice. Expression of LOX-1 can be induced after macrophage-like differentiation in vitro in human peripheral blood monocytes and the related cell line THP-1 cells. Furthermore, LOX-1 expression can also be detected in resident peritoneal macrophages, and can be upregulated by an inflammatory cytokine TNF-alpha. These results suggest that LOX-1 in macrophages may play an important role in Ox-LDL uptake and subsequent foam cell formation in this cell type.

  1. Renal tubular receptor imaging with iodine-131-labeled peanut lectin: pharmacokinetics and renal clearance mechanism in animals

    SciTech Connect

    Boniface, G.R.; Suresh, M.R.; Willans, D.J.; Tam, Y.K.; Shysh, A.; Longenecker, B.M.; Noujaim, A.A.

    1986-05-01

    Intravenously administered peanut lectin (PNA), iodinated with /sup 131/I ((/sup 131/I)PNA), is rapidly cleared from the plasma by the kidneys in dogs (clearance (total body) = 17.52 +/- 8.74 ml/min). Dynamic gamma camera renal scintigraphy demonstrated renal accumulation and excretion phases of the (/sup 131/I)PNA renogram in dogs and rabbits (% injection dose-at-peak = 21.8 +/- 3.3% and 19.6 +/- 4.3%, time-to-peak = 44.6 +/- 4.8 min and 37.2 +/- 6.9 min, respectively). Immunoperoxidase staining of kidney sections, following i.v. administered PNA, demonstrated predominant accumulation by the proximal tubules of mice, rabbits, and dogs. The basement membrane was intensely stained at early times p.i. while intracellular and luminal PNA was evident within 1 hr. Urine analysis confirmed the presence of intact (/sup 131/I)PNA in the bladder contents, while protein degradation products, and a small percentage of the free iodide (less than 5%) were noted within 1 hr p.i. The relative proportion of free iodide increased at later times p.i. (greater than 6 hr). A receptor mediated excretion mechanism is proposed for the clearance of PNA and may be useful for the study of renal tubular function.

  2. Enhancement of angiogenesis by a 27 kDa lectin from perivitelline fluid of horseshoe crab embryos through upregulation of VEGF and its receptor.

    PubMed

    Surekha, K L; Waghchoude, Meenal; Ghaskadbi, Surendra

    2013-01-25

    Angiogenesis, the expansion of a capillary network, is implicated in several pathological conditions. Drug-based inhibition of angiogenesis is being explored as therapy. Conversely, therapeutic angiogenesis contributes to control conditions such as ischemia. Here we report pro-angiogenic activity of perivitelline fluid (PVF) from Indian horseshoe crab embryos and one of its purified fractions, a 27 kDa lectin, using the chick embryonic chorioallantoic membrane assay. Enhancement in number and diameter of blood vessels after treatment with PVF and lectin suggested their pro-angiogenic effect. Quantitative RT-PCR showed that this effect is mediated through modulation of expression of VEGF and VEGFR-2/kinase domain receptor genes. PMID:23316979

  3. A rice lectin receptor-like kinase that is involved in innate immune responses also contributes to seed germination.

    PubMed

    Cheng, Xiaoyan; Wu, Yan; Guo, Jianping; Du, Bo; Chen, Rongzhi; Zhu, Lili; He, Guangcun

    2013-11-01

    Seed germination and innate immunity both have significant effects on plant life spans because they control the plant's entry into the ecosystem and provide defenses against various external stresses, respectively. Much ecological evidence has shown that seeds with high vigor are generally more tolerant of various environmental stimuli in the field than those with low vigor. However, there is little genetic evidence linking germination and immunity in plants. Here, we show that the rice lectin receptor-like kinase OslecRK contributes to both seed germination and plant innate immunity. We demonstrate that knocking down the OslecRK gene depresses the expression of α-amylase genes, reducing seed viability and thereby decreasing the rate of seed germination. Moreover, it also inhibits the expression of defense genes, and so reduces the resistance of rice plants to fungal and bacterial pathogens as well as herbivorous insects. Yeast two-hybrid and co-immunoprecipitation experiments revealed that OslecRK interacts with an actin-depolymerizing factor (ADF) in vivo via its kinase domain. Moreover, the rice adf mutant exhibited a reduced seed germination rate due to the suppression of α-amylase gene expression. This mutant also exhibited depressed immune responses and reduced resistance to biotic stresses. Our results thus provide direct genetic evidence for a common physiological pathway connecting germination and immunity in plants. They also partially explain the common observation that high-vigor seeds often perform well in the field. The dual effects of OslecRK may be indicative of progressive adaptive evolution in rice.

  4. Association between soluble lectin-like oxidized low-density lipoprotein receptor 1 levels and coronary slow flow phenomenon

    PubMed Central

    Caglar, Ilker Murat; Ozde, Cem; Caglar, Fatma Nihan Turhan; Akturk, Ibrahim Faruk; Ugurlucan, Murat; Karakaya, Osman

    2016-01-01

    Introduction The coronary slow flow phenomenon (CSFP) has been associated with myocardial ischemia, myocardial infarction, life-threatening arrhythmias, sudden cardiac death and increased cardiovascular mortality similar to coronary artery disease (CAD). Possible underlying mechanisms of CSFP are endothelial dysfunction, chronic inflammation, microvascular dysfunction and diffuse atherosclerosis. Soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) seems to play an important role in the pathogenesis of atherosclerosis. We hypothesized that sLOX-1 might be associated with CSFP, and aimed to research the relationship between sLOX-1 and CSFP. Material and methods Forty patients with angiographically proven CSFP and 43 patients with a normal coronary flow pattern (NCFP) were included in this study. Coronary blood flow was measured according to the Thrombolysis In Myocardial Infarction (TIMI) frame count method. sLOX-1 levels were measured in all study subjects. Results Serum levels of sLOX-1 were significantly higher in the CSFP group than the NCFP group (1061.80 ±422.20 ng/ml vs. 500.043 ±282.97 ng/ml, p < 0.001, respectively). Multivariate logistic regression analysis including sLOX-1, MPV, GGT and uric acid levels revealed a significant association between sLOX-1 levels and CSFP (Exp (B)/OR: 1.006, 95% CI: 1.002–1.010, p = 0.001). Conclusions The present study demonstrated that serum sLOX-1 levels were significantly higher in patients with CSFP and there was a strong association between high sLOX-1 levels and CSFP. High serum sLOX-1 levels may have an important role in the pathogenesis of CSFP. Future studies are needed to confirm these results. PMID:26925116

  5. Serum Lectin-Like Oxidized-Low Density Lipoprotein Receptor-1 and Adiponectin Levels Are Associated With Coronary Artery Disease Accompanied With Metabolic Syndrome

    PubMed Central

    Md Sayed, Ali Sheikh; Zhao, Zhenyu; Guo, Lanyan; Li, Fei; Deng, Xu; Deng, Hai; Xia, Ke; Yang, Tianlun

    2014-01-01

    Background: Coronary artery disease (CAD) is a major public health problem for developed and developing countries and is the single leading cause of death worldwide. Objectives: There is very few evidence regarding changes of both serum Lectin-like oxidized-low density lipoprotein receptor-1 (LOX-1) and adiponectin in patients with CAD accompanied with metabolic syndrome (MS). Here we aimed to evaluate serum levels of LOX-1 and adiponectin in patients with CAD accompanied with MS. Patients and Methods: Thirty patients with coronary artery disease without metabolic syndrome, 30 patients with coronary artery disease and metabolic syndrome, 30 ones with metabolic syndrome and 30 healthy subjects were enrolled. For all subjects, a questionnaire was filled to collect data, and peripheral blood samples were collected aseptically from the antecubital vein to measure serum Lectin-like oxidized-low density lipoprotein receptor-1 and adiponectin levels by enzyme-linked immunosorbent assay. Results: Serum LOX-1 level was highest in CAD + MS group; the difference between control and disease groups was statistically significant (P < 0.001). Adiponectin level had the lowest value in CAD + MS group; the difference between control and disease groups was statistically significant (P < 0.05). No significant differences were observed in serum Lectin-like oxidized-low density lipoprotein receptor-1and adiponectin in patients with different ages and gender. Serum LOX-1 level was changed negatively and linearly (R2 = 0.721) correlated with adiponectin level in different groups. Conclusions: Patient with CAD and MS had higher risk than those with only CAD because of lipid and glucose metabolism abnormalities. Combination measurements of serum LOX-1 and adiponectin levels may be helpful to evaluate the severity of CAD together with MS. PMID:25389471

  6. Arabidopsis Lectin Receptor Kinases LecRK-IX.1 and LecRK-IX.2 Are Functional Analogs in Regulating Phytophthora Resistance and Plant Cell Death.

    PubMed

    Wang, Yan; Cordewener, Jan H G; America, Antoine H P; Shan, Weixing; Bouwmeester, Klaas; Govers, Francine

    2015-09-01

    L-type lectin receptor kinases (LecRK) are potential immune receptors. Here, we characterized two closely-related Arabidopsis LecRK, LecRK-IX.1 and LecRK-IX.2, of which T-DNA insertion mutants showed compromised resistance to Phytophthora brassicae and Phytophthora capsici, with double mutants showing additive susceptibility. Overexpression of LecRK-IX.1 or LecRK-IX.2 in Arabidopsis and transient expression in Nicotiana benthamiana increased Phytophthora resistance but also induced cell death. Phytophthora resistance required both the lectin domain and kinase activity, but for cell death, the lectin domain was not needed. Silencing of the two closely related mitogen-activated protein kinase genes NbSIPK and NbNTF4 in N. benthamiana completely abolished LecRK-IX.1-induced cell death but not Phytophthora resistance. Liquid chromatography-mass spectrometry analysis of protein complexes coimmunoprecipitated in planta with LecRK-IX.1 or LecRK-IX.2 as bait, resulted in the identification of the N. benthamiana ABC transporter NbPDR1 as a potential interactor of both LecRK. The closest homolog of NbPDR1 in Arabidopsis is ABCG40, and coimmunoprecipitation experiments showed that ABCG40 associates with LecRK-IX.1 and LecRK-IX.2 in planta. Similar to the LecRK mutants, ABCG40 mutants showed compromised Phytophthora resistance. This study shows that LecRK-IX.1 and LecRK-IX.2 are Phytophthora resistance components that function independent of each other and independent of the cell-death phenotype. They both interact with the same ABC transporter, suggesting that they exploit similar signal transduction pathways.

  7. CNL, a ricin B-like lectin from mushroom Clitocybe nebularis, induces maturation and activation of dendritic cells via the toll-like receptor 4 pathway

    PubMed Central

    Švajger, Urban; Pohleven, Jure; Kos, Janko; Štrukelj, Borut; Jeras, Matjaž

    2011-01-01

    A novel lectin, isolated from the basidiomycete mushroom Clitocybe nebularis and termed C. nebularis lectin (CNL), exhibits an immunostimulatory effect on the most potent antigen-presenting cells, the dendritic cells (DCs). Treatment of human monocyte-derived DCs with CNL in doses from 1 to 10 μg/ml resulted in a dose-dependent induction of overall DC maturation characteristics. Exposure of DCs to CNL for 48 hr resulted in extensive up-regulation of co-stimulatory molecules CD80 and CD86, as well as of the maturation marker CD83 and HLA-DR molecules. Such CNL-matured DCs (CNL-DCs) were capable of inducing a T helper type 1-polarized response in naive CD4+ CD45RA+ T cells in 5-day allogeneic co-cultures. The allostimulatory potential of CNL-DCs was significantly increased relative to untreated controls, as was their capacity to produce several pro-inflammatory cytokines such as interleukin-6, interleukin-8 and tumour necrosis factor-α. By using a specific Toll-like receptor 4 (TLR4) signalling inhibitor, CLI-095, as well as Myd88 inhibitory peptide, we have shown that DC activation by CNL is completely dependent on the TLR4 activation pathway. Furthermore, activation of TLR4 by CNL was confirmed via TLR4 reporter assay. Measurement of p65 nuclear factor-κB and p38 mitogen-activated protein kinase (MAPK) phosphorylation levels following CNL stimulation of DCs revealed primarily an increase in nuclear factor-κB activity, with less effect on the induction of p38 MAPK signalling than of lipopolysaccharide-matured DCs. The CNL had the ability to activate human DCs in such a way as to subsequently direct T helper type 1 T-cell responses. Our results encourage the use of mushroom-derived lectins for use in therapeutic strategies with aims such as to strengthen anti-tumour immune responses. PMID:22044067

  8. Pea lectin receptor-like kinase functions in salinity adaptation without yield penalty, by alleviating osmotic and ionic stresses and upregulating stress-responsive genes.

    PubMed

    Vaid, Neha; Pandey, Prashant; Srivastava, Vineet Kumar; Tuteja, Narendra

    2015-05-01

    Lectin receptor-like kinases (LecRLKs) are members of RLK family composed of lectin-like extracellular recognition domain, transmembrane domain and cytoplasmic kinase domain. LecRLKs are plasma membrane proteins believed to be involved in signal transduction. However, most of the members of the protein family even in plants have not been functionally well characterized. Herein, we show that Pisum sativum LecRLK (PsLecRLK) localized in plasma membrane systems and/or other regions of the cell and its transcript upregulated under salinity stress. Overexpression of PsLecRLK in transgenic tobacco plants confers salinity stress tolerance by alleviating both the ionic as well the osmotic component of salinity stress. The transgenic plants show better tissue compartmentalization of Na(+) and higher ROS scavenging activity which probably results in lower membrane damage, improved growth and yield maintenance even under salinity stress. Also, expression of several genes involved in cellular homeostasis is perturbed by PsLecRLK overexpression. Alleviation of osmotic and ionic components of salinity stress along with reduced oxidative damage and upregulation of stress-responsive genes in transgenic plants under salinity stress conditions could be possible mechanism facilitating enhanced stress tolerance. This study presents PsLecRLK as a promising candidate for crop improvement and also opens up new avenue to investigate its signalling pathway.

  9. Fraction A of armadillo submandibular glycoprotein and its desialylated product as sialyl-Tn and Tn receptors for lectins.

    PubMed

    Wu, A M; Shen, F; Herp, A; Song, S C; Wu, J H

    1995-02-27

    Fraction A of the armadillo submandibular glycoprotein (ASG-A) is one of the simplest glycoproteins among mammalian salivary mucins. The carbohydrate side chains of this mucous glycoprotein have one-third of the NeuAc alpha 2-->6GalNAc (sialyl-Tn) sequence and two thirds of Tn (GalNAc alpha-->Ser/Thr) residues. Those of the desialylated product (ASG-Tn) are almost exclusively unsubstituted GalNAc residues (Tn determinant). When the binding properties of these glycoproteins were tested by a precipitin assay with Gal, GalNAc and GlcNAc specific lectins, it was found that ASG-Tn reacted strongly with all of the Tn-active lectins and completely precipitated Vicia villosa (VVL both B4 and mixture of A and B), Maclura pomifera (MPA), and Artocarpus integrifolia (jacalin) lectins. However, it precipitated poorly or negligibly with Ricinus communis (RCA1); Dolichos biflorus (DBA); Viscum album, ML-I; Arachis hypogaea (PNA), and Triticum vulgaris (WGA). The reactivity of ASG-A (sialyl-Tn) was as active as that of ASG-Tn with MPA and less or slightly less active than that of ASG-Tn with VVL-A+B, VVL-B4, HPA, WFA, and jacalin, as one-third of its Tn was sialylated. These findings indicate that ASG-A and its desialylated product (ASG-Tn) are highly useful reagents for the differentiation of Tn, T (Gal beta 1-->3GalNAc), A (GalNAc alpha 1-->3Gal) or Gal specific lectins and monoclonal antibodies against such epitopes.

  10. Lectin-like bacteriocins from Pseudomonas spp. utilise D-rhamnose containing lipopolysaccharide as a cellular receptor.

    PubMed

    McCaughey, Laura C; Grinter, Rhys; Josts, Inokentijs; Roszak, Aleksander W; Waløen, Kai I; Cogdell, Richard J; Milner, Joel; Evans, Tom; Kelly, Sharon; Tucker, Nicholas P; Byron, Olwyn; Smith, Brian; Walker, Daniel

    2014-02-01

    Lectin-like bacteriocins consist of tandem monocot mannose-binding domains and display a genus-specific killing activity. Here we show that pyocin L1, a novel member of this family from Pseudomonas aeruginosa, targets susceptible strains of this species through recognition of the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide that is predominantly a homopolymer of D-rhamnose. Structural and biophysical analyses show that recognition of CPA occurs through the C-terminal carbohydrate-binding domain of pyocin L1 and that this interaction is a prerequisite for bactericidal activity. Further to this, we show that the previously described lectin-like bacteriocin putidacin L1 shows a similar carbohydrate-binding specificity, indicating that oligosaccharides containing D-rhamnose and not D-mannose, as was previously thought, are the physiologically relevant ligands for this group of bacteriocins. The widespread inclusion of d-rhamnose in the lipopolysaccharide of members of the genus Pseudomonas explains the unusual genus-specific activity of the lectin-like bacteriocins.

  11. Lectin-Like Bacteriocins from Pseudomonas spp. Utilise D-Rhamnose Containing Lipopolysaccharide as a Cellular Receptor

    PubMed Central

    Josts, Inokentijs; Roszak, Aleksander W.; Waløen, Kai I.; Cogdell, Richard J.; Milner, Joel; Evans, Tom; Kelly, Sharon; Tucker, Nicholas P.; Byron, Olwyn; Smith, Brian; Walker, Daniel

    2014-01-01

    Lectin-like bacteriocins consist of tandem monocot mannose-binding domains and display a genus-specific killing activity. Here we show that pyocin L1, a novel member of this family from Pseudomonas aeruginosa, targets susceptible strains of this species through recognition of the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide that is predominantly a homopolymer of d-rhamnose. Structural and biophysical analyses show that recognition of CPA occurs through the C-terminal carbohydrate-binding domain of pyocin L1 and that this interaction is a prerequisite for bactericidal activity. Further to this, we show that the previously described lectin-like bacteriocin putidacin L1 shows a similar carbohydrate-binding specificity, indicating that oligosaccharides containing d-rhamnose and not d-mannose, as was previously thought, are the physiologically relevant ligands for this group of bacteriocins. The widespread inclusion of d-rhamnose in the lipopolysaccharide of members of the genus Pseudomonas explains the unusual genus-specific activity of the lectin-like bacteriocins. PMID:24516380

  12. Solution Structure and Sugar-Binding Mechanism of Mouse Latrophilin-1 RBL: a 7TM Receptor-Attached Lectin-Like Domain

    PubMed Central

    Vakonakis, Ioannis; Langenhan, Tobias; Prömel, Simone; Russ, Andreas; Campbell, Iain D.

    2008-01-01

    Summary Latrophilin-1 (Lat-1), a target receptor for α-Latrotoxin, is a putative G protein-coupled receptor implicated in synaptic function. The extracellular portion of Lat-1 contains a rhamnose binding lectin (RBL)-like domain of unknown structure. RBL domains, first isolated from the eggs of marine species, are also found in the ectodomains of other metazoan transmembrane proteins, including a recently discovered coreceptor of the neuronal axon guidance molecule SLT-1/Slit. Here, we describe a structure of this domain from the mouse Lat-1. RBL adopts a unique α/β fold with long structured loops important for monosaccharide recognition, as shown in the structure of a complex with L-rhamnose. Sequence alignments and mutagenesis show that residues important for carbohydrate binding are often absent in other receptor-attached examples of RBL, including the SLT-1/Slit coreceptor. We postulate that this domain class facilitates direct protein-protein interactions in many transmembrane receptors. PMID:18547526

  13. Killer Cell Lectin-like Receptor G1 Inhibits NK Cell Function through Activation of Adenosine 5'-Monophosphate-Activated Protein Kinase.

    PubMed

    Müller-Durovic, Bojana; Lanna, Alessio; Polaco Covre, Luciana; Mills, Rachel S; Henson, Sian M; Akbar, Arne N

    2016-10-01

    NK cells are the first line of defense against infected and transformed cells. Defective NK cell activity was shown to increase susceptibility for viral infections and reduce tumor immune-surveillance. With age, the incidence of infectious diseases and malignancy rises dramatically, suggesting that impaired NK cell function might contribute to disease in these individuals. We found an increased frequency of NK cells with high expression of the inhibitory killer cell lectin-like receptor G1 (KLRG1) in individuals >70 y. The role of KLRG1 in ageing is not known, and the mechanism of KLRG1-induced inhibition of NK cell function is not fully understood. We report that NK cells with high KLRG1 expression spontaneously activate the metabolic sensor AMP-activated protein kinase (AMPK) and that activation of AMPK negatively regulates NK cell function. Pre-existing AMPK activity is further amplified by ligation of KLRG1 in these cells, which leads to internalization of the receptor and allows interaction with AMPK. We show that KLRG1 activates AMPK by preventing its inhibitory dephosphorylation by protein phosphatase-2C rather than inducing de novo kinase activation. Finally, inhibition of KLRG1 or AMPK prevented KLRG1-induced activation of AMPK and reductions in NK cell cytotoxicity, cytokine secretion, proliferation, and telomerase expression. This novel signaling pathway links metabolic sensing, effector function, and cell differentiation with inhibitory receptor signaling that may be exploited to enhance NK cell activity during ageing.

  14. The Consequences of Multiple Simultaneous C-Type Lectin–Ligand Interactions: DCIR Alters the Endo-Lysosomal Routing of DC-SIGN

    PubMed Central

    García-Vallejo, Juan J.; Bloem, Karien; Knippels, Léon M. J.; Garssen, Johan; van Vliet, Sandra J.; van Kooyk, Yvette

    2015-01-01

    Antigen-presenting cells (APCs) are equipped with multiple receptors to allow proper pathogen recognition and capture. C-type lectin receptors (CLRs) recognize glycan structures on pathogens and endogenous glycoproteins for internalization and antigen processing and presentation. Often, the glycan specificity of these receptors is overlapping and/or pathogens are decorated with ligands for multiple CLRs, posing the question whether interference or cooperativity within the CLR family exists. Here, we used imaging flow cytometry to investigate the internalization properties of four different CLRs [mannose receptor, DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), macrophage galactose-type lectin, and dendritic cell immunoreceptor (DCIR)] on different APCs, as well as their intracellular routing. Although the internalization score of the investigated CLRs was similar on monocytes, macrophages, and dendritic cells (DCs), DCIR internalization rates were lower compared to the other CLRs. Upon triggering, DCIR routed to intracellular compartments outside of the classical endo-lysosomal pathway, resulting in poor CD4+ T-cell stimulation. Although DC maturation reduced CLR expression levels, it did not affect their internalization rates. Although CLR internalization appeared to be independently regulated, DC-SIGN routing was affected when DCIR was triggered simultaneously. In conclusion, our results provide new insights for the design of DC-based immunotherapeutic strategies and suggest that DCIR is an inferior target in this respect. PMID:25806031

  15. [Progress of pattern recognition receptors of molluscs].

    PubMed

    Gao, Qian; Zhao, Qin-ping; Ma, Xiao-xue; Dong, Hui-fen

    2015-08-01

    Molluscs have established complete innate immunity to defense against pathogens. The pattern recognition receptors (PRRs) are the sensory receptors of molluscs to resist outside invaders, as the first reactor to initiate the innate immune response. Some PRRs have been identified in several molluscs, including Toll-like receptors (TLRs) , C-type lectins, galectins, lipopolysaccharide-β-1,3-glucan binding protein (LGBP), Clq domain-containing protein (ClqDC), and peptidoglycan recognition protein (PGRP). PRRs have various biological activities and play important roles in the defense system of molluscs. This paper reviews the research progress of PRRs in molluscs.

  16. Lectin-like oxidized low-density lipoprotein receptor-1 abrogation causes resistance to inflammatory bone destruction in mice, despite promoting osteoclastogenesis in the steady state.

    PubMed

    Nakayachi, Mai; Ito, Junta; Hayashida, Chiyomi; Ohyama, Yoko; Kakino, Akemi; Okayasu, Mari; Sato, Takuya; Ogasawara, Toru; Kaneda, Toshio; Suda, Naoto; Sawamura, Tatsuya; Hakeda, Yoshiyuki

    2015-06-01

    Inflammatory bone diseases have been attributed to increased bone resorption by augmented and activated bone-resorbing osteoclasts in response to inflammation. Although the production of diverse proinflammatory cytokines is induced at the inflamed sites, the inflammation also generates reactive oxygen species that modify many biological compounds, including lipids. Among the oxidized low-density lipoprotein (LDL) receptors, lectin-like oxidized LDL receptor-1 (LOX-1), which is a key molecule in the pathogenesis of multifactorial inflammatory atherosclerosis, was downregulated with osteoclast differentiation. Here, we demonstrate that LOX-1 negatively regulates osteoclast differentiation by basically suppressing the cell-cell fusion of preosteoclasts. The LOX-1-deleted (LOX-1(-/-)) mice consistently decreased the trabecular bone mass because of elevated bone resorption during the growing phase. In contrast, when the calvaria was inflamed by a local lipopolysaccharide-injection, the inflammation-induced bone destruction accompanied by the elevated expression of osteoclastogenesis-related genes was reduced by LOX-1 deficiency. Moreover, the expression of receptor activator of NF-κB ligand (RANKL), a trigger molecule for osteoclast differentiation, evoked by the inflammation was also abrogated in the LOX-1(-/-) mice. Osteoblasts, the major producers of RANKL, also expressed LOX-1 in response to proinflammatory agents, interleukin-1β and prostaglandin E2. In the co-culture of LOX-1(-/-) osteoblasts and wild-type osteoclast precursors, the osteoclastogenesis induced by interleukin-1β and prostaglandin E2 decreased; this process occurred in parallel with the downregulation of osteoblastic RANKL expression. Collectively, LOX-1 abrogation results in resistance to inflammatory bone destruction, despite promoting osteoclastogenesis in the steady state. Our findings indicate the novel involvement of LOX-1 in physiological bone homeostasis and inflammatory bone diseases.

  17. Inhibition of lectin-like oxidized low-density lipoprotein receptor-1 reduces cardiac fibroblast proliferation by suppressing GATA Binding Protein 4.

    PubMed

    Liu, Bin; Liu, Ning-Ning; Liu, Wei-Hua; Zhang, Shuang-Wei; Zhang, Jing-Zhi; Li, Ai-Qun; Liu, Shi-Ming

    2016-07-01

    Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and GATA Binding Protein 4 (GATA4) are important for the growth of cardiac fibroblasts (CFs). When deregulated, LOX-1 and GATA4 can cause cardiac remodeling. In the present study, we found novel evidence that GATA4 was required for the LOX-1 regulation of CF proliferation. The inhibition of LOX-1 by RNA interference LOX-1 lentivirus resulted in the loss of PI3K/Akt activation and GATA4 protein expression. The overexpression of LOX-1 by lentivirus rescued CF proliferation, PI3K/Akt activation, and GATA4 protein expression. Moreover, GATA4 overexpression enhanced CF proliferation with LOX-1 inhibition. We also found that the inhibition of PI3K/Akt activation by LY294002, a PI3K inhibitor, reduced cell proliferation and protein level of GATA4. In summary, GATA4 may play an important role in the LOX-1 and PI3K/Akt regulation of CF proliferation. PMID:27216460

  18. GsSRK, a G-type lectin S-receptor-like serine/threonine protein kinase, is a positive regulator of plant tolerance to salt stress.

    PubMed

    Sun, Xiao-Li; Yu, Qing-Yue; Tang, Li-Li; Ji, Wei; Bai, Xi; Cai, Hua; Liu, Xiao-Fei; Ding, Xiao-Dong; Zhu, Yan-Ming

    2013-03-15

    Receptor-like protein kinases (RLKs) play vital roles in sensing outside signals, yet little is known about RLKs functions and roles in stress signal perception and transduction in plants, especially in wild soybean. Through the microarray analysis, GsSRK was identified as an alkaline (NaHCO3)-responsive gene, and was subsequently isolated from Glycine soja by homologous cloning. GsSRK encodes a 93.22kDa protein with a highly conserved serine/threonine protein kinase catalytic domain, a G-type lectin region, and an S-locus region. Real-time PCR results showed that the expression levels of GsSRK were largely induced by ABA, salt, and drought stresses. Over expression of GsSRK in Arabidopsis promoted seed germination, as well as primary root and rosette leaf growth during the early stages of salt stress. Compared to the wild type Arabidopsis, GsSRK overexpressors exhibited enhanced salt tolerance and higher yields under salt stress, with higher chlorophyll content, lower ion leakage, higher plant height, and more siliques at the adult developmental stage. Our studies suggest that GsSRK plays a crucial role in plant response to salt stress.

  19. Therapeutic Administration of KM+ Lectin Protects Mice Against Paracoccidioides brasiliensis Infection via Interleukin-12 Production in a Toll-Like Receptor 2-Dependent Mechanism

    PubMed Central

    Coltri, Kely C.; Oliveira, Leandro L.; Pinzan, Camila F.; Vendruscolo, Patrícia E.; Martinez, Roberto; Goldman, Maria Helena; Panunto-Castelo, Ademilson; Roque-Barreira, Maria-Cristina

    2008-01-01

    KM+ is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM+ (jfKM+) and its recombinant counterpart (rKM+) in experimental paracoccidioidomycosis. To this end, jfKM+ or rKM+ was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM+-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM+-treated mice presented higher levels of nitric oxide, IL-12, interferon-γ, and tumor necrosis factor-α, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM+ led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM+ on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule. PMID:18599609

  20. Therapeutic administration of KM+ lectin protects mice against Paracoccidioides brasiliensis infection via interleukin-12 production in a toll-like receptor 2-dependent mechanism.

    PubMed

    Coltri, Kely C; Oliveira, Leandro L; Pinzan, Camila F; Vendruscolo, Patrícia E; Martinez, Roberto; Goldman, Maria Helena; Panunto-Castelo, Ademilson; Roque-Barreira, Maria-Cristina

    2008-08-01

    KM(+) is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM(+) (jfKM(+)) and its recombinant counterpart (rKM(+)) in experimental paracoccidioidomycosis. To this end, jfKM(+) or rKM(+) was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM(+)-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM(+)-treated mice presented higher levels of nitric oxide, IL-12, interferon-gamma, and tumor necrosis factor-alpha, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM(+) led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM(+) on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule.

  1. Cilostazol prevents remnant lipoprotein particle-induced monocyte adhesion to endothelial cells by suppression of adhesion molecules and monocyte chemoattractant protein-1 expression via lectin-like receptor for oxidized low-density lipoprotein receptor activation.

    PubMed

    Park, So Youn; Lee, Jeong Hyun; Kim, Yong Ki; Kim, Chi Dae; Rhim, Byung Yong; Lee, Won Suk; Hong, Ki Whan

    2005-03-01

    This study shows cilostazol effect to prevent remnant lipoprotein particle (RLP)-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). Upon incubation of HUVECs with RLP (50 microg/ml), adherent monocytes significantly increased by 3.3-fold with increased cell surface expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1, E-selectin, and monocyte chemoattractant protein-1 (MCP-1). Cilostazol ( approximately 1-100 microM) concentration dependently repressed these variables as did (E)3-[(4-t-butylphenyl)sulfonyl]-2-propenenitrile (BAY 11-7085) (10 microM), a specific nuclear factor-kappaB (NF-kappaB) inhibitor. Cilostazol effects were significantly antagonized by iberiotoxin (1 microM), a maxi-K channel blocker. RLP significantly increased expression of lectin-like receptor for oxidized low-density lipoprotein (LDL) (LOX-1) receptor protein. Upon transfection with antisense LOX-1 oligodeoxynucleotide (As-LOX-1), LOX-1 receptor expression was reduced, whereas HUVECs with sense LOX-1 oligodeoxynucleotide did express high LOX-1 receptor. RLP-stimulated superoxide and tumor necrosis factor-alpha levels were significantly lowered with decreased expression of VCAM-1 and MCP-1 by transfection with As-LOX-1 as did polyinosinic acid (10 microg/ml, a LOX-1 receptor inhibitor). RLP significantly degraded inhibitory kappaBalpha in the cytoplasm and activated nuclear factor-kappaB (NF-kappaB) p65 in the nucleus of HUVECs with increased luciferase activity of NF-kappaB, all of which were reversed by cilostazol (10 microM), BAY 11-7085, and polyinosinic acid. Together, cilostazol suppresses RLP-stimulated increased monocyte adhesion to HUVECs by suppression of LOX-1 receptor-coupled NF-kappaB-dependent nuclear transcription via mediation of the maxi-K channel opening.

  2. Host defence against Candida albicans and the role of pattern-recognition receptors.

    PubMed

    Gauglitz, Gerd G; Callenberg, Helene; Weindl, Günther; Korting, Hans C

    2012-05-01

    Recognition of Candida albicans is mediated by several classes of pattern-recognition receptors, including Toll-like receptors and C-type lectin receptors. Cell wall components of C. albicans, interact with the pattern-recognition receptors, which are expressed by different cells, primarily antigen-presenting cells. This review aims to discuss the different pattern-recognition receptors responsible for recognition of special structures of C. albicans, which are known to activate intracellular signals that finally lead to directed and efficient host defence.

  3. Identification of 4-hydroxy-2-nonenal-histidine adducts that serve as ligands for human lectin-like oxidized LDL receptor-1.

    PubMed

    Kumano-Kuramochi, Miyuki; Shimozu, Yuuki; Wakita, Chika; Ohnishi-Kameyama, Mayumi; Shibata, Takahiro; Matsunaga, Shigeru; Takano-Ishikawa, Yuko; Watanabe, Jun; Goto, Masao; Xie, Qiuhong; Komba, Shiro; Uchida, Koji; Machida, Sachiko

    2012-02-15

    LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) is an endothelial scavenger receptor that is important for the uptake of OxLDL (oxidized low-density lipoprotein) and contributes to the pathogenesis of atherosclerosis. However, the precise structural motifs of OxLDL that are recognized by LOX-1 are unknown. In the present study, we have identified products of lipid peroxidation of OxLDL that serve as ligands for LOX-1. We used CHO (Chinese-hamster ovary) cells that stably express LOX-1 to evaluate the ability of BSA modified by lipid peroxidation to compete with AcLDL (acetylated low-density lipoprotein). We found that HNE (4-hydroxy-2-nonenal)-modified proteins most potently inhibited the uptake of AcLDL. On the basis of the findings that HNE-modified BSA and oxidation of LDL resulted in the formation of HNE-histidine Michael adducts, we examined whether the HNE-histidine adducts could serve as ligands for LOX-1. The authentic HNE-histidine adduct inhibited the uptake of AcLDL in a dose-dependent manner. Furthermore, we found the interaction of LOX-1 with the HNE-histidine adduct to have a dissociation constant of 1.22×10(-8) M using a surface plasmon resonance assay. Finally, we showed that the HNE-histidine adduct stimulated the formation of reactive oxygen species and activated extracellular-signal-regulated kinase 1/2 and NF-κB (nuclear factor κB) in HAECs (human aortic endothelial cells); these signals initiate endothelial dysfunction and lead to atherosclerosis. The present study provides intriguing insights into the molecular details of LOX-1 recognition of OxLDL.

  4. CaLecRK-S.5, a pepper L-type lectin receptor kinase gene, confers broad-spectrum resistance by activating priming

    PubMed Central

    Woo, Joo Yong; Jeong, Kwang Ju; Kim, Young Jin; Paek, Kyung-Hee

    2016-01-01

    In Arabidopsis, several L-type lectin receptor kinases (LecRKs) have been identified as putative immune receptors. However, to date, there have been few analyses of LecRKs in crop plants. Virus-induced gene silencing of CaLecRK-S.5 verified the role of CaLecRK-S.5 in broad-spectrum resistance. Compared with control plants, CaLecRK-S.5-silenced plants showed reduced hypersensitive response, reactive oxygen species burst, secondary metabolite production, mitogen-activated protein kinase activation, and defense-related gene expression in response to Tobacco mosaic virus pathotype P0 (TMV-P0) infection. Suppression of CaLecRK-S.5 expression significantly enhanced the susceptibility to Pepper mild mottle virus pathotype P1,2,3, Xanthomonas campestris pv. vesicatoria, Phytophthora capsici, as well as TMV-P0. Additionally, β-aminobutyric acid treatment and a systemic acquired resistance assay revealed that CaLecRK-S.5 is involved in priming of plant immunity. Pre-treatment with β-aminobutyric acid before viral infection restored the reduced disease resistance phenotypes shown in CaLecRK-S.5-silenced plants. Systemic acquired resistance was also abolished in CaLecRK-S.5-silenced plants. Finally, RNA sequencing analysis indicated that CaLecRK-S.5 positively regulates plant immunity at the transcriptional level. Altogether, these results suggest that CaLecRK-S.5-mediated broad-spectrum resistance is associated with the regulation of priming. PMID:27647723

  5. Curcumin eliminates oxidized LDL roles in activating hepatic stellate cells by suppressing gene expression of lectin-like oxidized LDL receptor-1.

    PubMed

    Kang, Qiaohua; Chen, Anping

    2009-11-01

    Type II diabetes mellitus (T2DM) is often accompanied by non-alcoholic steatohepatitis (NASH) and associated with hypercholesterolemia, that is, increased levels of plasma low-density lipoprotein (LDL) and oxidized LDL (ox-LDL). Approximately one-third of NASH develops hepatic fibrosis. The role of hypercholesterolemia in T2DM and NASH-associated hepatic fibrogenesis remains obscure. We previously reported that the phytochemical curcumin inhibited the activation of hepatic stellate cells (HSCs), the major effector cells during hepatic fibrogenesis, and protected the liver from fibrogenesis in vitro and in vivo. The aims of this study are to evaluate the role of ox-LDL in activation of HSCs, to assess curcumin effects on eliminating the role of ox-LDL, and to further explore the underlying mechanisms. In this report, we observe that ox-LDL alters the expression of genes closely relevant to HSC activation, which is eliminated by curcumin. Curcumin suppresses gene expression of lectin-like oxidized LDL receptor-1 (LOX-1), leading to the blockade of the transport of extracellular ox-LDL into cells. This suppressive effect of curcumin results from the interruption of Wnt signaling and the activation of peroxisome proliferator-activated receptor-gamma (PPARgamma). In conclusion, these results support our initial hypothesis and demonstrate that ox-LDL stimulates HSC activation, which is eliminated by curcumin by suppressing lox-1 expression by interrupting Wnt signaling and stimulating PPARgamma activity. These results provide novel insights into the role of ox-LDL in T2DM and NASH-associated hepatic fibrogenesis and mechanisms by which curcumin suppresses ox-LDL-induced HSC activation, as well as the implication of curcumin in the treatment of T2DM and NASH-associated hepatic fibrosis. PMID:19736547

  6. The Lectin Receptor Kinase-VI.2 Is Required for Priming and Positively Regulates Arabidopsis Pattern-Triggered Immunity[C][W

    PubMed Central

    Singh, Prashant; Kuo, Yi-Chun; Mishra, Swati; Tsai, Chia-Hong; Chien, Chih-Cheng; Chen, Ching-Wei; Desclos-Theveniau, Marie; Chu, Po-Wei; Schulze, Birgit; Chinchilla, Delphine; Boller, Thomas; Zimmerli, Laurent

    2012-01-01

    Plant cells can be sensitized toward a subsequent pathogen attack by avirulent pathogens or by chemicals such as β-aminobutyric acid (BABA). This process is called priming. Using a reverse genetic approach in Arabidopsis thaliana, we demonstrate that the BABA-responsive L-type lectin receptor kinase-VI.2 (LecRK-VI.2) contributes to disease resistance against the hemibiotrophic Pseudomonas syringae and the necrotrophic Pectobacterium carotovorum bacteria. Accordingly, LecRK-VI.2 mRNA levels increased after bacterial inoculation or treatments with microbe-associated molecular patterns (MAMPs). We also show that LecRK-VI.2 is required for full activation of pattern-triggered immunity (PTI); notably, lecrk-VI.2-1 mutants show reduced upregulation of PTI marker genes, impaired callose deposition, and defective stomatal closure. Overexpression studies combined with genome-wide microarray analyses indicate that LecRK-VI.2 positively regulates the PTI response. LecRK-VI.2 is demonstrated to act upstream of mitogen-activated protein kinase signaling, but independently of reactive oxygen production and BOTRYTIS-INDUCED KINASE1 phosphorylation. In addition, complex formation between the MAMP receptor FLAGELLIN SENSING2 and its signaling partner BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 is observed in flg22-treated lecrk-VI.2-1 mutants. LecRK-VI.2 is also required for full BABA-induced resistance and priming of PTI. Our work identifies LecRK-VI.2 as a novel mediator of the Arabidopsis PTI response and provides insight into molecular mechanisms governing priming. PMID:22427336

  7. Diversified Carbohydrate-Binding Lectins from Marine Resources

    PubMed Central

    Ogawa, Tomohisa; Watanabe, Mizuki; Naganuma, Takako; Muramoto, Koji

    2011-01-01

    Marine bioresources produce a great variety of specific and potent bioactive molecules including natural organic compounds such as fatty acids, polysaccharides, polyether, peptides, proteins, and enzymes. Lectins are also one of the promising candidates for useful therapeutic agents because they can recognize the specific carbohydrate structures such as proteoglycans, glycoproteins, and glycolipids, resulting in the regulation of various cells via glycoconjugates and their physiological and pathological phenomenon through the host-pathogen interactions and cell-cell communications. Here, we review the multiple lectins from marine resources including fishes and sea invertebrate in terms of their structure-activity relationships and molecular evolution. Especially, we focus on the unique structural properties and molecular evolution of C-type lectins, galectin, F-type lectin, and rhamnose-binding lectin families. PMID:22312473

  8. Differentiation of Bacillus anthracis and other Bacillus species by lectins.

    PubMed Central

    Cole, H B; Ezzell, J W; Keller, K F; Doyle, R J

    1984-01-01

    Bacillus anthracis was agglutinated by several lectins, including those from Griffonia simplicifolia, Glycine max, Abrus precatorius, and Ricinus communis. Some strains of Bacillus cereus var. mycoides (B. mycoides) were strongly reactive with the lectin from Helix pomatia and weakly reactive with the G. max lectin. The differential interactions between Bacillus species and lectins afforded a means of distinguishing B. anthracis from other bacilli. B. cereus strains exhibited heterogeneity with respect to agglutination patterns by lectins but could readily be differentiated from B. anthracis and the related B. mycoides. Spores of B. anthracis and B. mycoides retained lectin receptors, although the heating of spores or vegetative cells at 100 degrees C resulted in a decrease in their ability to be specifically agglutinated. Fluorescein-conjugated lectin of G. max stained vegetative cells of B. anthracis uniformly, suggesting that the distribution of lectin receptors was continuous over the entire cellular surface. B. anthracis cells grown under conditions to promote the production of capsular poly(D-glutamyl peptide) were also readily agglutinated by the lectins, suggesting that the lectin reactive sites penetrate the polypeptide layer. Trypsin, subtilisin, lysozyme, and mutanolysin did not modify the reactivity of B. anthracis with the G. max agglutinin, although the same enzymes markedly diminished the interaction between the lectin and B. mycoides. Because the lectins which interact with B. anthracis are specific for alpha-D-galactose or 2-acetamido-2-deoxy-alpha-D-galactose residues, it is likely that the bacteria possess cell surface polymers which contain these sugars. Lectins may prove useful in the laboratory identification of B. anthracis and possibly other pathogenic Bacillus species, such as B. cereus. Images PMID:6418761

  9. Molecular Recognition of Paired Receptors in the Immune System

    PubMed Central

    Kuroki, Kimiko; Furukawa, Atsushi; Maenaka, Katsumi

    2012-01-01

    Cell surface receptors are responsible for regulating cellular function on the front line, the cell membrane. Interestingly, accumulating evidence clearly reveals that the members of cell surface receptor families have very similar extracellular ligand-binding regions but opposite signaling systems, either inhibitory or stimulatory. These receptors are designated as paired receptors. Paired receptors often recognize not only physiological ligands but also non-self ligands, such as viral and bacterial products, to fight infections. In this review, we introduce several representative examples of paired receptors, focusing on two major structural superfamilies, the immunoglobulin-like and the C-type lectin-like receptors, and explain how these receptors distinguish self and non-self ligands to maintain homeostasis in the immune system. We further discuss the evolutionary aspects of these receptors as well as the potential drug targets for regulating diseases. PMID:23293633

  10. Lectins discriminate between pathogenic and nonpathogenic South American trypanosomes

    SciTech Connect

    de Miranda Santos, I.K.; Pereira, M.E.

    1984-09-01

    Cell surface carbohydrates of Trypanosoma cruzi, Trypanosoma rangeli, and Trypanosoma conorhini were analyzed by a micro-agglutination assay employing 27 highly purified lectins and by binding assays using various /sup 125/I-labeled lectins. The following seven lectins discriminated between the trypanosomes: 1) tomato lectin (an N-acetyl-D-glucosamine-binding protein), both in purified form and as crude tomato juice; 2) Bauhinea purpurea and Sophora japonica lectins (both N-acetyl-D-galactosamine-binding proteins), which selectively agglutinated T. cruzi; 3) Vicia villosa (an N-acetyl-D-galactosamine-binding protein) which was specific for T. rangeli; 4) peanut lectin (a D-galactose-binding protein) both in purified form and as crude saline extract; and 5) Ulex europaeus and Lotus tetragonolobus (both L-fucose-binding proteins) lectins which reacted only with T. conorhini. Binding studies with 125I-labeled lectins were performed to find whether unagglutinated cells of the three different species of trypanosomes might have receptors for these lectins, in which case absence of agglutination could be due to a peculiar arrangement of the receptors. These assays essentially confirmed the agglutination experiments.

  11. Arsenic augments the uptake of oxidized LDL by upregulating the expression of lectin-like oxidized LDL receptor in mouse aortic endothelial cells

    SciTech Connect

    Hossain, Ekhtear; Ota, Akinobu; Karnan, Sivasundaram; Damdindorj, Lkhagvasuren; Takahashi, Miyuki; Konishi, Yuko; Konishi, Hiroyuki; Hosokawa, Yoshitaka

    2013-12-15

    Although chronic arsenic exposure is a well-known risk factor for cardiovascular diseases, including atherosclerosis, the molecular mechanism underlying arsenic-induced atherosclerosis remains obscure. Therefore, this study aimed to elucidate this molecular mechanism. We examined changes in the mRNA level of the lectin-like oxidized LDL (oxLDL) receptor (LOX-1) in a mouse aortic endothelial cell line, END-D, after sodium arsenite (SA) treatment. SA treatment significantly upregulated LOX-1 mRNA expression; this finding was also verified at the protein expression level. Flow cytometry and fluorescence microscopy analyses showed that the cellular uptake of fluorescence (Dil)-labeled oxLDL was significantly augmented with SA treatment. In addition, an anti-LOX-1 antibody completely abrogated the augmented uptake of Dil-oxLDL. We observed that SA increased the levels of the phosphorylated forms of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB)/p65. SA-induced upregulation of LOX-1 protein expression was clearly prevented by treatment with an antioxidant, N-acetylcysteine (NAC), or an NF-κB inhibitor, caffeic acid phenethylester (CAPE). Furthermore, SA-augmented uptake of Dil-oxLDL was also prevented by treatment with NAC or CAPE. Taken together, our results indicate that arsenic upregulates LOX-1 expression through the reactive oxygen species-mediated NF-κB signaling pathway, followed by augmented cellular oxLDL uptake, thus highlighting a critical role of the aberrant LOX-1 signaling pathway in the pathogenesis of arsenic-induced atherosclerosis. - Highlights: • Sodium arsenite (SA) increases LOX-1 expression in mouse aortic endothelial cells. • SA enhances cellular uptake of oxidized LDL in dose-dependent manner. • SA-induced ROS generation enhances phosphorylation of NF-κB. • SA upregulates LOX-1 expression through ROS-activated NF-κB signaling pathway.

  12. Arsenic augments the uptake of oxidized LDL by upregulating the expression of lectin-like oxidized LDL receptor in mouse aortic endothelial cells.

    PubMed

    Hossain, Ekhtear; Ota, Akinobu; Karnan, Sivasundaram; Damdindorj, Lkhagvasuren; Takahashi, Miyuki; Konishi, Yuko; Konishi, Hiroyuki; Hosokawa, Yoshitaka

    2013-12-15

    Although chronic arsenic exposure is a well-known risk factor for cardiovascular diseases, including atherosclerosis, the molecular mechanism underlying arsenic-induced atherosclerosis remains obscure. Therefore, this study aimed to elucidate this molecular mechanism. We examined changes in the mRNA level of the lectin-like oxidized LDL (oxLDL) receptor (LOX-1) in a mouse aortic endothelial cell line, END-D, after sodium arsenite (SA) treatment. SA treatment significantly upregulated LOX-1 mRNA expression; this finding was also verified at the protein expression level. Flow cytometry and fluorescence microscopy analyses showed that the cellular uptake of fluorescence (Dil)-labeled oxLDL was significantly augmented with SA treatment. In addition, an anti-LOX-1 antibody completely abrogated the augmented uptake of Dil-oxLDL. We observed that SA increased the levels of the phosphorylated forms of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB)/p65. SA-induced upregulation of LOX-1 protein expression was clearly prevented by treatment with an antioxidant, N-acetylcysteine (NAC), or an NF-κB inhibitor, caffeic acid phenethylester (CAPE). Furthermore, SA-augmented uptake of Dil-oxLDL was also prevented by treatment with NAC or CAPE. Taken together, our results indicate that arsenic upregulates LOX-1 expression through the reactive oxygen species-mediated NF-κB signaling pathway, followed by augmented cellular oxLDL uptake, thus highlighting a critical role of the aberrant LOX-1 signaling pathway in the pathogenesis of arsenic-induced atherosclerosis. PMID:24145059

  13. Structure and binding analysis of Polyporus squamosus lectin in complex with the Neu5Ac[alpha]2-6Gal[beta]1-4GlcNAc human-type influenza receptor

    SciTech Connect

    Kadirvelraj, Renuka; Grant, Oliver C.; Goldstein, Irwin J.; Winter, Harry C.; Tateno, Hiroaki; Fadda, Elisa; Woods, Robert J.

    2013-03-07

    Glycan chains that terminate in sialic acid (Neu5Ac) are frequently the receptors targeted by pathogens for initial adhesion. Carbohydrate-binding proteins (lectins) with specificity for Neu5Ac are particularly useful in the detection and isolation of sialylated glycoconjugates, such as those associated with pathogen adhesion as well as those characteristic of several diseases including cancer. Structural studies of lectins are essential in order to understand the origin of their specificity, which is particularly important when employing such reagents as diagnostic tools. Here, we report a crystallographic and molecular dynamics (MD) analysis of a lectin from Polyporus squamosus (PSL) that is specific for glycans terminating with the sequence Neu5Ac{alpha}2-6Gal{beta}. Because of its importance as a histological reagent, the PSL structure was solved (to 1.7 {angstrom}) in complex with a trisaccharide, whose sequence (Neu5Ac{alpha}2-6Gal{beta}1-4GlcNAc) is exploited by influenza A hemagglutinin for viral adhesion to human tissue. The structural data illuminate the origin of the high specificity of PSL for the Neu5Ac{alpha}2-6Gal sequence. Theoretical binding free energies derived from the MD data confirm the key interactions identified crystallographically and provide additional insight into the relative contributions from each amino acid, as well as estimates of the importance of entropic and enthalpic contributions to binding.

  14. Structure and binding analysis of Polyporus squamosus lectin in complex with the Neu5Acα2-6Galβ1-4GlcNAc human-type influenza receptor

    PubMed Central

    Kadirvelraj, Renuka; Grant, Oliver C; Goldstein, Irwin J; Winter, Harry C; Tateno, Hiroaki; Fadda, Elisa; Woods, Robert J

    2011-01-01

    Glycan chains that terminate in sialic acid (Neu5Ac) are frequently the receptors targeted by pathogens for initial adhesion. Carbohydrate-binding proteins (lectins) with specificity for Neu5Ac are particularly useful in the detection and isolation of sialylated glycoconjugates, such as those associated with pathogen adhesion as well as those characteristic of several diseases including cancer. Structural studies of lectins are essential in order to understand the origin of their specificity, which is particularly important when employing such reagents as diagnostic tools. Here, we report a crystallographic and molecular dynamics (MD) analysis of a lectin from Polyporus squamosus (PSL) that is specific for glycans terminating with the sequence Neu5Acα2-6Galβ. Because of its importance as a histological reagent, the PSL structure was solved (to 1.7 Å) in complex with a trisaccharide, whose sequence (Neu5Acα2-6Galβ1-4GlcNAc) is exploited by influenza A hemagglutinin for viral adhesion to human tissue. The structural data illuminate the origin of the high specificity of PSL for the Neu5Acα2-6Gal sequence. Theoretical binding free energies derived from the MD data confirm the key interactions identified crystallographically and provide additional insight into the relative contributions from each amino acid, as well as estimates of the importance of entropic and enthalpic contributions to binding. PMID:21436237

  15. Sugared biomaterial binding lectins: achievements and perspectives.

    PubMed

    Bojarová, P; Křen, V

    2016-07-19

    Lectins, a distinct group of glycan-binding proteins, play a prominent role in the immune system ranging from pathogen recognition and tuning of inflammation to cell adhesion or cellular signalling. The possibilities of their detailed study expanded along with the rapid development of biomaterials in the last decade. The immense knowledge of all aspects of glycan-lectin interactions both in vitro and in vivo may be efficiently used in bioimaging, targeted drug delivery, diagnostic and analytic biological methods. Practically applicable examples comprise photoluminescence and optical biosensors, ingenious three-dimensional carbohydrate microarrays for high-throughput screening, matrices for magnetic resonance imaging, targeted hyperthermal treatment of cancer tissues, selective inhibitors of bacterial toxins and pathogen-recognising lectin receptors, and many others. This review aims to present an up-to-date systematic overview of glycan-decorated biomaterials promising for interactions with lectins, especially those applicable in biology, biotechnology or medicine. The lectins of interest include galectin-1, -3 and -7 participating in tumour progression, bacterial lectins from Pseudomonas aeruginosa (PA-IL), E. coli (Fim-H) and Clostridium botulinum (HA33) or DC-SIGN, receptors of macrophages and dendritic cells. The spectrum of lectin-binding biomaterials covered herein ranges from glycosylated organic structures, calixarene and fullerene cores over glycopeptides and glycoproteins, functionalised carbohydrate scaffolds of cyclodextrin or chitin to self-assembling glycopolymer clusters, gels, micelles and liposomes. Glyconanoparticles, glycan arrays, and other biomaterials with a solid core are described in detail, including inorganic matrices like hydroxyapatite or stainless steel for bioimplants. PMID:27075026

  16. Lectins from edible mushrooms.

    PubMed

    Singh, Senjam Sunil; Wang, Hexiang; Chan, Yau Sang; Pan, Wenliang; Dan, Xiuli; Yin, Cui Ming; Akkouh, Ouafae; Ng, Tzi Bun

    2014-12-31

    Mushrooms are famous for their nutritional and medicinal values and also for the diversity of bioactive compounds they contain including lectins. The present review is an attempt to summarize and discuss data available on molecular weights, structures, biological properties, N-terminal sequences and possible applications of lectins from edible mushrooms. It further aims to update and discuss/examine the recent advancements in the study of these lectins regarding their structures, functions, and exploitable properties. A detailed tabling of all the available data for N-terminal sequences of these lectins is also presented here.

  17. Lectin-binding properties of Aeromonas caviae strains

    PubMed Central

    Rocha-de-Souza, Cláudio M.; Hirata-Jr, Raphael; Mattos-Guaraldi, Ana L.; Freitas-Almeida, Angela C.; Andrade, Arnaldo F. B.

    2008-01-01

    The cell surface carbohydrates of four strains of Aeromonas caviae were analyzed by agglutination and lectin-binding assays employing twenty highly purified lectins encompassing all sugar specificities. With the exception of L-fucose and sialic acid, the sugar residues were detected in A. caviae strains. A marked difference, however, in the pattern of cell surface carbohydrates in different A. caviae isolates was observed. Specific receptors for Tritricum vulgaris (WGA), Lycopersicon esculentum (LEL) and Solanum tuberosum (STA) (D-GlcNAc-binding lectins) were found only in ATCC 15468 strain, whereas Euonymus europaeus (EEL, D-Gal-binding lectin) sites were present exclusively in AeQ32 strain, those for Helix pomatia (HPA, D-GalNAc-binding lectin) in AeC398 and AeV11 strains, and for Canavalia ensiformes (Con A, D-Man-binding lectin) in ATCC 15468, AeC398, AeQ32 and AeV11 strains, after bacterial growing at 37°C. On the other hand, specific receptors for WGA and EEL were completely abrogated growing the bacteria at 22°C. Binding studies with 125I- labeled lectins from WGA, EEL and Con A were performed. These assays essentially confirmed the selectivity, demonstrated in the agglutination assays of these lectins for the A. caviae strains. PMID:24031204

  18. Lectin-like oxidized LDL receptor-1 expresses in mouse bone marrow-derived mesenchymal stem cells and stimulates their proliferation

    SciTech Connect

    Zhang, Fenxi; Wang, Congrui; Jing, Suhua; Ren, Tongming; Li, Yonghai; Cao, Yulin; Lin, Juntang

    2013-04-15

    The bone marrow-derived mesenchymal stem cells (bmMSCs) have been widely used in cell transplant therapy, and the proliferative ability of bmMSCs is one of the determinants of the therapy efficiency. Lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) as a transmembrane protein is responsible for binding, internalizing and degrading oxidized low density lipoprotein (ox-LDL). It has been identified that LOX-1 is expressed in endothelial cells, vascular smooth muscle cells, cardiomyocytes, fibroblasts and monocytes. In these cells, low concentration of ox-LDL (<40 μg/mL) stimulates their proliferation via LOX-1 activation. However, it is poor understood that whether LOX-1 is expressed in bmMSCs and which role it plays. In this study, we investigated the status of LOX-1 expression in bmMSCs and its function on bmMSC proliferation. Our results showed that primary bmMSCs exhibiting a typical fibroblast-like morphology are positive for CD44 and CD90, but negative for CD34 and CD45. LOX-1 in both mRNA and protein levels is highly expressed in bmMSCs. Meanwhile, bmMSCs exhibit a strong potential to take up ox-LDL. Moreover, LOX-1 expression in bmMSCs is upregulated by ox-LDL with a dose- and time-dependent manner. Presence of ox-LDL also enhances the proliferation of bmMSCs. Knockdown of LOX-1 expression significantly inhibits ox-LDL-induced bmMSC proliferation. These findings indicate that LOX-1 plays a role in bmMSC proliferation. - Highlights: ► LOX-1 expresses in bmMSCs and mediates uptake of ox-LDL. ► Ox-LDL stimulates upregulation of LOX-1 in bmMSCs. ► Ox-LDL promotes bmMSC proliferation and expression of Mdm2, phosphor-Akt, phosphor-ERK1/2 and phosphor-NF-κB. ► LOX-1 siRNA inhibits ox-LDL-induced bmMSC proliferation and expression cell survival signals.

  19. Histological and lectin histochemical studies on the olfactory and respiratory mucosae of the sheep.

    PubMed

    Ibrahim, Dalia; Nakamuta, Nobuaki; Taniguchi, Kazumi; Yamamoto, Yoshio; Taniguchi, Kazuyuki

    2014-03-01

    The olfactory and respiratory mucosae of the Corriedale sheep were examined using lectin histochemistry in order to clarify the histochemical and glycohistochemical differences between these two tissues. The olfactory epithelium was stained with 13 lectins out of 21 lectins examined, while the respiratory epithelium was positive to 16 lectins. The free border of both of the olfactory and respiratory epithelia was stained with 12 lectins: Wheat germ agglutinin (WGA), succinylated-wheat germ agglutinin (s-WGA), Lycopersicon esculentum lectin (LEL), Solanum tuberosum lectin (STL), Datura stramonium lectin (DSL), Soybean agglutinin (SBA), Bandeiraea simplicifolia lectin-I (BSL-I), Ricinus communis agglutinin-I (RCA-120), Erythrina cristagalli lectin (ECL), Concanavalin A (Con A), Phaseolus vulgaris agglutinin-E (PHA-E) and Phaseolus vulgaris agglutinin-L (PHA-L). The associated glands of the olfactory mucosa, Bowman's glands, were stained with 13 lectins. While both the goblet cells and mucous nasal glands were stained with 8 lectins; five of them (WGA, s-WGA, STL, Vicia villosa agglutinin (VVA) and ECL) were mutually positive among the Bowman's glands, mucous nasal glands and the goblet cells. These findings indicate that the glycohistochemical characteristics of the free borders of both olfactory and respiratory epithelia are similar to each other, suggesting that secretions from the Bowman's glands and those of the goblet cells and mucous nasal glands are partially exchanged between the surface of two epithelia to contribute the functions of the respiratory epithelium and the olfactory receptor cells, respectively. PMID:24200894

  20. Lectin domains at the frontiers of plant defense

    PubMed Central

    Lannoo, Nausicaä; Van Damme, Els J. M.

    2014-01-01

    Plants are under constant attack from pathogens and herbivorous insects. To protect and defend themselves, plants evolved a multi-layered surveillance system, known as the innate immune system. Plants sense their encounters upon perception of conserved microbial structures and damage-associated patterns using cell-surface and intracellular immune receptors. Plant lectins and proteins with one or more lectin domains represent a major part of these receptors. The whole group of plant lectins comprises an elaborate collection of proteins capable of recognizing and interacting with specific carbohydrate structures, either originating from the invading organisms or from damaged plant cell wall structures. Due to the vast diversity in protein structures, carbohydrate recognition domains and glycan binding specificities, plant lectins constitute a very diverse protein superfamily. In the last decade, new types of nucleocytoplasmic plant lectins have been identified and characterized, in particular lectins expressed inside the nucleus and the cytoplasm of plant cells often as part of a specific plant response upon exposure to different stress factors or changing environmental conditions. In this review, we provide an overview on plant lectin motifs used in the constant battle against pathogens and predators during plant defenses. PMID:25165467

  1. The insecticidal activity of recombinant garlic lectins towards aphids.

    PubMed

    Fitches, Elaine; Wiles, Duncan; Douglas, Angela E; Hinchliffe, Gareth; Audsley, Neil; Gatehouse, John A

    2008-10-01

    The heterodimeric and homodimeric garlic lectins ASAI and ASAII were produced as recombinant proteins in the yeast Pichia pastoris. The proteins were purified as functional dimeric lectins, but underwent post-translational proteolysis. Recombinant ASAII was a single homogenous polypeptide which had undergone C-terminal processing similar to that occurring in planta. The recombinant ASAI was glycosylated and subject to variable and heterogenous proteolysis. Both lectins showed insecticidal effects when fed to pea aphids (Acyrthosiphon pisum) in artificial diet, ASAII being more toxic than ASAI at the same concentration. Acute toxicity (mortality at < or =48 h exposure; similar timescale to starvation) was only apparent at the highest lectin concentrations tested (2.0 mg ml(-)1), but dose-dependent chronic toxicity (mortality at >3d exposure) was observed over the concentration range 0.125-2.0 mg ml(-1). The recombinant lectins caused mortality in both symbiotic and antibiotic-treated aphids, showing that toxicity is not dependent on the presence of the bacterial symbiont (Buchnera aphidicola), or on interaction with symbiont proteins, such as the previously identified lectin "receptor" symbionin. A pull-down assay coupled with peptide mass fingerprinting identified two abundant membrane-associated aphid gut proteins, alanyl aminopeptidase N and sucrase, as "receptors" for lectin binding. PMID:18707000

  2. Characterization of the Receptors for Mycobacterial Cord Factor in Guinea Pig

    PubMed Central

    Toyonaga, Kenji; Miyake, Yasunobu; Yamasaki, Sho

    2014-01-01

    Guinea pig is a widely used animal for research and development of tuberculosis vaccines, since its pathological disease process is similar to that present in humans. We have previously reported that two C-type lectin receptors, Mincle (macrophage inducible C-type lectin, also called Clec4e) and MCL (macrophage C-type lectin, also called Clec4d), recognize the mycobacterial cord factor, trehalose-6,6′-dimycolate (TDM). Here, we characterized the function of the guinea pig homologue of Mincle (gpMincle) and MCL (gpMCL). gpMincle directly bound to TDM and transduced an activating signal through ITAM-bearing adaptor molecule, FcRγ. Whereas, gpMCL lacked C-terminus and failed to bind to TDM. mRNA expression of gpMincle was detected in the spleen, lymph nodes and peritoneal macrophages and it was strongly up-regulated upon stimulation of zymosan and TDM. The surface expression of gpMincle was detected on activated macrophages by a newly established monoclonal antibody that also possesses a blocking activity. This antibody potently suppressed TNF production in BCG-infected macrophages. Collectively, gpMincle is the TDM receptor in the guinea pig and TDM-Mincle axis is involved in host immune responses against mycobacteria. PMID:24533147

  3. Comparative Genomics of Natural Killer Cell Receptor Gene Clusters

    PubMed Central

    Kelley, James; Walter, Lutz; Trowsdale, John

    2005-01-01

    Many receptors on natural killer (NK) cells recognize major histocompatibility complex class I molecules in order to monitor unhealthy tissues, such as cells infected with viruses, and some tumors. Genes encoding families of NK receptors and related sequences are organized into two main clusters in humans: the natural killer complex on Chromosome 12p13.1, which encodes C-type lectin molecules, and the leukocyte receptor complex on Chromosome 19q13.4, which encodes immunoglobulin superfamily molecules. The composition of these gene clusters differs markedly between closely related species, providing evidence for rapid, lineage-specific expansions or contractions of sets of loci. The choice of NK receptor genes is polarized in the two species most studied, mouse and human. In mouse, the C-type lectin-related Ly49 gene family predominates. Conversely, the single Ly49 sequence is a pseudogene in humans, and the immunoglobulin superfamily KIR gene family is extensive. These different gene sets encode proteins that are comparable in function and genetic diversity, even though they have undergone species-specific expansions. Understanding the biological significance of this curious situation may be aided by studying which NK receptor genes are used in other vertebrates, especially in relation to species-specific differences in genes for major histocompatibility complex class I molecules. PMID:16132082

  4. Purification and characterization of Dolichos lablab lectin.

    PubMed

    Mo, H; Meah, Y; Moore, J G; Goldstein, I J

    1999-02-01

    The mannose/glucose-binding Dolichos lablab lectin (designated DLL) has been purified from seeds of Dolichos lablab (hyacinth bean) to electrophoretic homogeneity by affinity chromatography on an ovalbumin-Sepharose 4B column. The purified lectin gave a single symmetric protein peak with an apparent molecular mass of 67 kDa on gel filtration chromatography, and five bands ranging from 10 kDa to 22 kDa upon SDS-PAGE. N-Terminal sequence analysis of these bands revealed subunit heterogeneity due to posttranslational proteolytic truncation at different sites mostly at the carboxyl terminus. The carbohydrate binding properties of the purified lectin were investigated by three different approaches: hemagglutination inhibition assay, quantitative precipitation inhibition assay, and ELISA. On the basis of these studies, it is concluded that the Dolichos lablab lectin has neither an extended carbohydrate combining site, nor a hydrophobic binding site adjacent to it. The carbohydrate combining site of DLL appears to most effectively accommodate a nonreducing terminal alpha-d-mannosyl unit, and to be complementary to the C-3, C-4, and C-6 equatorial hydroxyl groups of alpha-d-mannopyranosyl and alpha-d-glucopyranosyl residues. DLL strongly precipitates murine IgM but not IgG, and the recent finding that this lectin interacts specifically with NIH 3T3 fibroblasts transfected with the Flt3 tyrosine kinase receptor and preserves human cord blood stem cells and progenitors in a quiescent state for prolonged periods in culture, make this lectin a valuable tool in biomedical research. PMID:9949194

  5. Lectin histochemical studies on the olfactory epithelium and vomeronasal organ in the Japanese striped snake, Elaphe quadrivirgata.

    PubMed

    Kondoh, Daisuke; Yamamoto, Yoshio; Nakamuta, Nobuaki; Taniguchi, Kazumi; Taniguchi, Kazuyuki

    2010-10-01

    The olfactory epithelium and the vomeronasal organ of the Japanese striped snake were examined by lectin histochemistry. Of the 21 lectins used in the study, all lectins except succinylated-wheat germ agglutinin (s-WGA) showed similar binding patterns in the vomeronasal receptor cells and the olfactory receptor cells with varying intensities. The binding patterns of s-WGA varied among individuals in the vomeronasal and olfactory receptor cells, respectively. Four lectins, Bandeiraea simplicifolia lectin-II (BSL-II), Dolichos biflorus agglutinin (DBA), Sophora japonica agglutinin (SJA), and Erythrina cristagalli lectin (ECL) stained secretory granules and the organelles in the olfactory supporting cells and did not stain them in the vomeronasal supporting cells. These results suggest that the glycoconjugate moieties are similar in the vomeronasal and olfactory receptor cells of the Japanese striped snake. PMID:20597100

  6. Multiple lectin detection by cell membrane affinity binding.

    PubMed

    Ribeiro, Ana; Catarino, Sofia; Ferreira, Ricardo Boavida

    2012-05-01

    Assuming that lectins evolved to recognise relatively complex and branched oligosaccharides or parts of them, rather than simple sugars, a procedure based on lectin affinity binding to isolated erythrocyte (or any other cell type) membranes is proposed. This methodology was validated using six pure commercial lectins, as well as lectins from total protein extracts of Arbutus unedo leaves. All commercial lectins, as well as five polypeptides from A. unedo leaves bound to the glycosylated membrane receptors and were eluted by the corresponding sugars. When compared to the standard affinity chromatography procedure involving an individual sugar bound to a solid matrix, the new method provides a single-step, effective detection method for lectins and allows the rapid screening of their profile present in any unknown protein solution, indicates their biological carbohydrate affinities as well as their sugar specificities (if any), enables the simultaneous analysis of a large number of samples, does not require any pre-purification steps, permits detection of additional lectins and provides data which are more relevant from the physiological point of view. PMID:22381939

  7. Lectins: production and practical applications

    PubMed Central

    2010-01-01

    Lectins are proteins found in a diversity of organisms. They possess the ability to agglutinate erythrocytes with known carbohydrate specificity since they have at least one non-catalytic domain that binds reversibly to specific monosaccharides or oligosaccharides. This articles aims to review the production and practical applications of lectins. Lectins are isolated from their natural sources by chromatographic procedures or produced by recombinant DNA technology. The yields of animal lectins are usually low compared with the yields of plant lectins such as legume lectins. Lectins manifest a diversity of activities including antitumor, immunomodulatory, antifungal, HIV-1 reverse transcriptase inhibitory, and anti-insect activities, which may find practical applications. A small number of lectins demonstrate antibacterial and anti-nematode activities. PMID:20890754

  8. Genetic variation in pattern recognition receptors: functional consequences and susceptibility to infectious disease.

    PubMed

    Jaeger, Martin; Stappers, Mark H T; Joosten, Leo A B; Gyssens, Inge C; Netea, Mihai G

    2015-01-01

    Cells of the innate immune system are equipped with surface and cytoplasmic receptors for microorganisms called pattern recognition receptors (PRRs). PRRs recognize specific pathogen-associated molecular patterns and as such are crucial for the activation of the immune system. Currently, five different classes of PRRs have been described: Toll-like receptors, C-type lectin receptors, nucleotide-binding oligomerization domain-like receptors, retinoic acid-inducible gene I-like receptors and absent in melanoma 2-like receptors. Following their discovery, many sequence variants in PRR genes have been uncovered and shown to be implicated in human infectious diseases. In this review, we will discuss the effect of genetic variation in PRRs and their signaling pathways on susceptibility to infectious diseases in humans.

  9. Sweet complementarity: the functional pairing of glycans with lectins.

    PubMed

    Gabius, H-J; Manning, J C; Kopitz, J; André, S; Kaltner, H

    2016-05-01

    Carbohydrates establish the third alphabet of life. As part of cellular glycoconjugates, the glycans generate a multitude of signals in a minimum of space. The presence of distinct glycotopes and the glycome diversity are mapped by sugar receptors (antibodies and lectins). Endogenous (tissue) lectins can read the sugar-encoded information and translate it into functional aspects of cell sociology. Illustrated by instructive examples, each glycan has its own ligand properties. Lectins with different folds can converge to target the same epitope, while intrafamily diversification enables functional cooperation and antagonism. The emerging evidence for the concept of a network calls for a detailed fingerprinting. Due to the high degree of plasticity and dynamics of the display of genes for lectins the validity of extrapolations between different organisms of the phylogenetic tree yet is inevitably limited. PMID:26956894

  10. Lectin-binding properties of different Leishmania species.

    PubMed

    Andrade, A F; Saraiva, E M

    1999-07-01

    Carbohydrate cell-surface residues on stationary promastigotes of 19 isolates of Leishmania were studied with a panel of 27 highly purified lectins, which were specific for N-acetyl-D-glucosamine, D-mannose, L-fucose, D-galactose, N-acetyl-D-galactosamine, and sialic acid. The specificity of the cell-surface carbohydrates was analyzed by agglutination and radioiodinated lectin-binding assays. L. (L.) amazonensis and L. (L.) donovani were agglutinated by 12 and 10 of the 27 lectins used, respectively. Artocarpus integrifolia lectin (Jacalin) was incapable of agglutinating the tested species of the donovani complex, and this result was confirmed by radioiodinated Jacalin-binding assays. Jacalin had an average of 3.8 x 10(6) receptors/L. (L) amazonensis promastigote and bound with an association constant of 5 x 10(6) M(-1).

  11. Mulberry leaf aqueous fractions inhibit TNF-alpha-induced nuclear factor kappaB (NF-kappaB) activation and lectin-like oxidized LDL receptor-1 (LOX-1) expression in vascular endothelial cells.

    PubMed

    Shibata, Yusuke; Kume, Noriaki; Arai, Hidenori; Hayashida, Kazutaka; Inui-Hayashida, Atsuko; Minami, Manabu; Mukai, Eri; Toyohara, Masako; Harauma, Akiko; Murayama, Toshinori; Kita, Toru; Hara, Saburo; Kamei, Kaeko; Yokode, Masayuki

    2007-07-01

    Mulberry (Morus Alba L., family Moraceae) leaf extracts have various biological effects including inhibition of oxidative modification of low-density lipoprotein (LDL), which is the major cause of atherosclerosis. Endothelial dysfunction elicited by oxidized LDL (Ox-LDL) has been implicated in atherogenesis. Lectin-like Ox-LDL receptor-1 (LOX-1), a cell-surface receptor for atherogenic Ox-LDL, appears to mediate Ox-LDL-induced inflammation, which may be crucial in atherogenesis. Previous studies revealed that expression of LOX-1 is highly inducible by proinflammatory stimuli, including tumor necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), and transforming growth factor-beta (TGF-beta). Therefore, we examined whether mulberry leaf aqueous fractions inhibit LOX-1 expression induced by proinflammatory stimuli. Pretreatment of cultured bovine aortic endothelial cells (BAECs) with mulberry leaf aqueous fractions inhibited TNF-alpha- and LPS-induced expression of LOX-1 at both protein and mRNA levels in a time- and concentration-dependent manner. In contrast, mulberry leaf aqueous fractions did not affect TGF-beta-induced LOX-1 expression. Furthermore, mulberry leaf aqueous fractions inhibited TNF-alpha-induced activation of nuclear factor-kappaB (NF-kappaB) and phosphorylation of inhibitory factor of NF-kappaB-alpha (IkappaB-alpha) in a time- and concentration-dependent fashion. Thus, mulberry leaf aqueous fractions suppress TNF-alpha- and LPS-induced LOX-1 gene expression, by inhibiting NF-kappaB activation.

  12. Animal lectins as self/non-self recognition molecules. Biochemical and genetic approaches to understanding their biological roles and evolution.

    PubMed

    Vasta, G R; Ahmed, H; Fink, N E; Elola, M T; Marsh, A G; Snowden, A; Odom, E W

    1994-04-15

    In recent years, the significant contributions from molecular research studies on animal lectins have elucidated structural aspects and provided clues not only to their evolution but also to their multiple biological functions. The experimental evidence has suggested that distinct, and probably unrelated, groups of molecules are included under the term "lectin." Within the invertebrate taxa, major groups of lectins can be identified: One group would include lectins that show significant homology to membrane-integrated or soluble vertebrate C-type lectins. The second would include those beta-galactosyl-specific lectins homologous to the S-type vertebrate lectins. The third group would be constituted by lectins that show homology to vertebrate pentraxins that exhibit lectin-like properties, such as C-reactive protein and serum amyloid P. Finally, there are examples that do not exhibit similarities to any of the aforementioned categories. Moreover, the vast majority of invertebrate lectins described so far cannot yet be placed in one or another group because of the lack of information regarding their primary structure. (See Table 1.) Animal lectins do not express a recombinatorial diversity like that of antibodies, but a limited diversity in recognition capabilities would be accomplished by the occurrence of multiple lectins with distinct specificities, the presence of more than one binding site, specific for different carbohydrates in a single molecule, and by certain "flexibility" of the binding sites that would allow the recognition of a range of structurally related carbohydrates. In order to identify the lectins' "natural" ligands, we have investigated the interactions between those proteins and the putative endogenous or exogenous glycosylated substances or cells that may be relevant to their biological function. Results from these studies, together with information on the biochemical properties of invertebrate and vertebrate lectins, including their structural

  13. Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin.

    PubMed

    Rauschenberg, Melanie; Fritz, Eva-Corrina; Schulz, Christian; Kaufmann, Tobias; Ravoo, Bart Jan

    2014-01-01

    The molecular recognition of carbohydrates and proteins mediates a wide range of physiological processes and the development of synthetic carbohydrate receptors ("synthetic lectins") constitutes a key advance in biomedical technology. In this article we report a synthetic lectin that selectively binds to carbohydrates immobilized in a molecular monolayer. Inspired by our previous work, we prepared a fluorescently labeled synthetic lectin consisting of a cyclic dimer of the tripeptide Cys-His-Cys, which forms spontaneously by air oxidation of the monomer. Amine-tethered derivatives of N-acetylneuraminic acid (NANA), β-D-galactose, β-D-glucose and α-D-mannose were microcontact printed on epoxide-terminated self-assembled monolayers. Successive prints resulted in simple microarrays of two carbohydrates. The selectivity of the synthetic lectin was investigated by incubation on the immobilized carbohydrates. Selective binding of the synthetic lectin to immobilized NANA and β-D-galactose was observed by fluorescence microscopy. The selectivity and affinity of the synthetic lectin was screened in competition experiments. In addition, the carbohydrate binding of the synthetic lectin was compared with the carbohydrate binding of the lectins concanavalin A and peanut agglutinin. It was found that the printed carbohydrates retain their characteristic selectivity towards the synthetic and natural lectins and that the recognition of synthetic and natural lectins is strictly orthogonal.

  14. Isolation of the galactose-binding lectin that mediates the in vitro adherence of Entamoeba histolytica.

    PubMed Central

    Petri, W A; Smith, R D; Schlesinger, P H; Murphy, C F; Ravdin, J I

    1987-01-01

    Entamoeba histolytica adheres to human colonic mucus, colonic epithelial cells, and other target cells via a galactose (Gal) or N-acetyl-D-galactosamine (GalNAc) inhibitable surface lectin. Blockade of this adherence lectin with Gal or GalNAc in vitro prevents amebic killing of target cells. We have identified and purified the adherence lectin by two methods: affinity columns derivatized with galactose monomers or galactose terminal glycoproteins, and affinity columns and immunoblots prepared with monoclonal antibodies that inhibit amebic adherence. By both methods the adherence lectin was identified as a 170-kD secreted and membrane-bound amebic protein. The surface location of the lectin was confirmed by indirect immunofluorescence. Purified lectin competitively inhibited amebic adherence to target cells by binding to receptors on the target Chinese hamster ovary cells in a Gal-inhibitable manner. Images PMID:2890654

  15. Lectin binding in meningiomas.

    PubMed

    Kleinert, R; Radner, H

    1987-01-01

    Forty-two meningiomas of different morphological sub-type were examined to determine their pattern of binding to 11 different lectins which characterize cell surface components such as carbohydrate residues. Histiocytic and xanthoma cells within meningiomas could be demonstrated with six different lectins: wheat germ agglutinin (WGA), peanut agglutinin (PNA) Bauhinia purpurea agglutinin (BPA), Helix pomatia agglutinin (HPA), Vicia fava agglutinin (VFA) and Soyabean agglutinin (SBA). Vascular elements including endothelial cells and intimal cells, bound Ulex europaeus agglutinin type 1 (UEA 1), WGA and HPA. The fibrous stroma in fibrous and fibroblastic meningiomas bound PNA, Laburnum alpinum agglutinin (LAA) and SBA. Tumour cells in meningotheliomatous meningiomas and some areas of anaplastic meningiomas bound Concanavalin A, PNA, LAA and VFA whereas tumour cells in fibrous and fibroblastic meningiomas bound BPA, LAA and VFA. Lectin binding has proved to be of value in detecting histiocytic and xanthoma cells together with vascular elements within meningiomas. In addition, the different lectin binding patterns allow different histological sub-types of meningioma to be distinguished although the biological significance of the binding patterns is unclear. PMID:3658105

  16. Cucumis sativus L-type lectin receptor kinase (CsLecRK) gene family response to Phytophthora melonis, Phytophthora capsici and water immersion in disease resistant and susceptible cucumber cultivars.

    PubMed

    Wu, Tingquan; Wang, Rui; Xu, Xiaomei; He, Xiaoming; Sun, Baojuan; Zhong, Yujuan; Liang, Zhaojuan; Luo, Shaobo; Lin, Yu'e

    2014-10-10

    L-type lectin receptor kinase (LecRK) proteins are an important family involved in diverse biological processes such as pollen development, senescence, wounding, salinity and especially in innate immunity in model plants such as Arabidopsis and tobacco. Till date, LecRK proteins or genes of cucumber have not been reported. In this study, a total of 25 LecRK genes were identified in the cucumber genome, unequally distributed across its seven chromosomes. According to similarity comparison of their encoded proteins, the Cucumis sativus LecRK (CsLecRK) genes were classified into six major clades (from Clade I to CladeVI). Expression of CsLecRK genes were tested using QRT-PCR method and the results showed that 25 CsLecRK genes exhibited different responses to abiotic (water immersion) and biotic (Phytophthora melonis and Phytophthora capsici inoculation) stresses, as well as that between disease resistant cultivar (JSH) and disease susceptible cultivar (B80). Among the 25 CsLecRK genes, we found CsLecRK6.1 was especially induced by P. melonis and P. capsici in JSH plants. All these results suggested that CsLecRK genes may play important roles in biotic and abiotic stresses.

  17. Lectins in human pathogenic fungi.

    PubMed

    Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

    2014-01-01

    Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).

  18. Lectins in human pathogenic fungi.

    PubMed

    Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

    2014-01-01

    Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). PMID:24270074

  19. Glycan and lectin biosensors

    PubMed Central

    Belický, Štefan; Katrlík, Jaroslav

    2016-01-01

    A short description about the importance of glycan biorecognition in physiological (blood cell type) and pathological processes (infections by human and avian influenza viruses) is provided in this review. Glycans are described as much better information storage media, compared to proteins or DNA, due to the extensive variability of glycan structures. Techniques able to detect an exact glycan structure are briefly discussed with the main focus on the application of lectins (glycan-recognising proteins) in the specific analysis of glycans still attached to proteins or cells/viruses. Optical, electrochemical, piezoelectric and micromechanical biosensors with immobilised lectins or glycans able to detect a wide range of analytes including whole cells/viruses are also discussed. PMID:27365034

  20. Glycan and lectin biosensors.

    PubMed

    Belický, Štefan; Katrlík, Jaroslav; Tkáč, Ján

    2016-06-30

    A short description about the importance of glycan biorecognition in physiological (blood cell type) and pathological processes (infections by human and avian influenza viruses) is provided in this review. Glycans are described as much better information storage media, compared to proteins or DNA, due to the extensive variability of glycan structures. Techniques able to detect an exact glycan structure are briefly discussed with the main focus on the application of lectins (glycan-recognising proteins) in the specific analysis of glycans still attached to proteins or cells/viruses. Optical, electrochemical, piezoelectric and micromechanical biosensors with immobilised lectins or glycans able to detect a wide range of analytes including whole cells/viruses are also discussed. PMID:27365034

  1. Cytokine production by human epithelial and endothelial cells following exposure to oral viridans streptococci involves lectin interactions between bacteria and cell surface receptors.

    PubMed Central

    Vernier, A; Diab, M; Soell, M; Haan-Archipoff, G; Beretz, A; Wachsmann, D; Klein, J P

    1996-01-01

    In order to examine the possible implication of human epithelial and endothelial cells in the pathogenesis of various diseases associated with oral viridans streptococci, we tested the immunomodulatory effects of 11 representative strains of oral viridans streptococci on human epithelial KB cells and endothelial cells. We then examined the possible role of two major adhesins from oral viridans streptococci, protein I/II and rhamnose-glucose polymers (RGPs), in this process. In this study we demonstrate that oral viridans streptococci are potent stimulators of interleukin-8 (IL-8) production from KB cells and of IL-6 and IL-8 production from endothelial cells. The ability of protein I/II and RGPs to contribute to these effects was then examined. Using biotinylated protein I/IIf and RGPs from Streptococcus mutans OMZ 175, we showed that these adhesins bind to KB and endothelial cells through specific interactions and that the binding of these molecules initiates the release of IL-8 from KB cells and of IL-6 and IL-8 from endothelial cells. These results suggest that protein I/IIf and RGPs play an important role in the interactions between bacteria and KB and endothelial cells in that similar cytokine profiles are obtained when cells are stimulated with bacteria or surface components. We also provide evidence that protein I/IIf binds to and stimulates KB and endothelial cells through lectin interactions and that N-acetyl neuraminic acid (NANA) and fucose present on cell surface glycoproteins may form the recognition site since binding and cytokine release can be inhibited by dispase and periodate treatment of cells and by NANA and fucose. These results demonstrate that oral viridans streptococci, probably by engaging two cell surface adhesins, exert immunomodulatory effects on human KB and endothelial cells. PMID:8757828

  2. Ethanol extract of propolis protects endothelial cells from oxidized low density lipoprotein-induced injury by inhibiting lectin-like oxidized low density lipoprotein receptor-1-mediated oxidative stress.

    PubMed

    Fang, Yongqi; Li, Jinguo; Ding, Mingde; Xu, Xiaoyan; Zhang, Jiajun; Jiao, Peng; Han, Ping; Wang, Jiafu; Yao, Shutong

    2014-12-01

    Lectin-like oxidized low density lipoprotein receptor-1 (LOX-1), as the primary oxidized low-density lipoprotein (ox-LDL) receptor on endothelial cells, plays a crucial role in endothelial injury, which is a driving force in the initiation and development of atherosclerosis. Our previous studies have shown that ethanol extract of propolis (EEP) promotes reverse cholesterol transport and inhibits atherosclerotic lesion development. However, the protective effects of EEP against ox-LDL-induced injury in endothelial cells and the underlying mechanisms are still unknown. This study was designed to test the hypothesis that EEP attenuates ox-LDL-induced endothelial oxidative injury via modulation of LOX-1-mediated oxidative stress. Our results showed that exposure of human umbilical vein endothelial cells (HUVECs) to ox-LDL (100 mg/L) led to the decrease in cell viability and increase in lactate dehydrogenase (LDH) release, caspase-3 activation, and apoptosis, whereas pretreatment with EEP (7.5, 15 and 30 mg/L) protected against such damages in a dose-dependent manner. In addition, EEP mitigated ox-LDL uptake by HUVECs and attenuated ox-LDL-upregulated LOX-1 expression both at the mRNA and protein levels. Moreover, EEP suppressed the ox-LDL-induced oxidative stress as assessed by decreased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, reactive oxygen species (ROS), and malondialdehyde (MDA) generation as well as increased antioxidant enzyme activities. Similar results were observed in the anti-LOX-1 antibody or diphenyleneiodonium (DPI)-pretreated HUVECs. These data indicate that EEP may protect HUVECs from ox-LDL-induced injury and that the mechanism at least partially involves its ability to inhibit endothelial LOX-1 upregulation and subsequent oxidative stress.

  3. Targeted delivery of antigen to hamster nasal lymphoid tissue with M-cell-directed lectins.

    PubMed Central

    Giannasca, P J; Boden, J A; Monath, T P

    1997-01-01

    The nasal cavity of a rodent is lined by an epithelium organized into distinct regional domains responsible for specific physiological functions. Aggregates of nasal lymphoid tissue (NALT) located at the base of the nasal cavity are believed to be sites of induction of mucosal immune responses to airborne antigens. The epithelium overlying NALT contains M cells which are specialized for the transcytosis of immunogens, as demonstrated in other mucosal tissues. We hypothesized that NALT M cells are characterized by distinct glycoconjugate receptors which influence antigen uptake and immune responses to transcytosed antigens. To identify glycoconjugates that may distinguish NALT M cells from other cells of the respiratory epithelium (RE), we performed lectin histochemistry on sections of the hamster nasal cavity with a panel of lectins. Many classes of glycoconjugates were found on epithelial cells in this region. While most lectins bound to sites on both the RE and M cells, probes capable of recognizing alpha-linked galactose were found to label the follicle-associated epithelium (FAE) almost exclusively. By morphological criteria, the FAE contains >90% M cells. To determine if apical glycoconjugates on M cells were accessible from the nasal cavity, an M-cell-selective lectin and a control lectin in parallel were administered intranasally to hamsters. The M-cell-selective lectin was found to specifically target the FAE, while the control lectin did not. Lectin bound to M cells in vivo was efficiently endocytosed, consistent with the role of M cells in antigen transport. Intranasal immunization with lectin-test antigen conjugates without adjuvant stimulated induction of specific serum immunoglobulin G, whereas antigen alone or admixed with lectin did not. The selective recognition of NALT M cells by a lectin in vivo provides a model for microbial adhesin-host cell receptor interactions on M cells and the targeted delivery of immunogens to NALT following intranasal

  4. MMBL proteins: from lectin to bacteriocin.

    PubMed

    Ghequire, Maarten G K; Loris, Remy; De Mot, René

    2012-12-01

    Arguably, bacteriocins deployed in warfare among related bacteria are among the most diverse proteinacous compounds with respect to structure and mode of action. Identification of the first prokaryotic member of the so-called MMBLs (monocot mannose-binding lectins) or GNA (Galanthus nivalis agglutinin) lectin family and discovery of its genus-specific killer activity in the Gram-negative bacteria Pseudomonas and Xanthomonas has added yet another kind of toxin to this group of allelopathic molecules. This novel feature is reminiscent of the protective function, on the basis of antifungal, insecticidal, nematicidal or antiviral activity, assigned to or proposed for several of the eukaryotic MMBL proteins that are ubiquitously distributed among monocot plants, but also occur in some other plants, fish, sponges, amoebae and fungi. Direct bactericidal activity can also be effected by a C-type lectin, but this is a mammalian protein that limits mucosal colonization by Gram-positive bacteria. The presence of two divergent MMBL domains in the novel bacteriocins raises questions about task distribution between modules and the possible role of carbohydrate binding in the specificity of target strain recognition and killing. Notably, bacteriocin activity was also demonstrated for a hybrid MMBL protein with an accessory protease-like domain. This association with one or more additional modules, often with predicted peptide-hydrolysing or -binding activity, suggests that additional bacteriotoxic proteins may be found among the diverse chimaeric MMBL proteins encoded in prokaryotic genomes. A phylogenetic survey of the bacterial MMBL modules reveals a mosaic pattern of strongly diverged sequences, mainly occurring in soil-dwelling and rhizosphere bacteria, which may reflect a trans-kingdom acquisition of the ancestral genes. PMID:23176516

  5. Lectin-like molecules in transcriptome of Littorina littorea hemocytes.

    PubMed

    Gorbushin, Alexander M; Borisova, Elena A

    2015-01-01

    The common periwinkle Littorina littorea was introduced in the list of models for comparative immunobiology as a representative of phylogenetically important taxon Caenogastropoda. Using Illumina sequencing technology, we de novo assembled the transcriptome of Littorina littorea hemocytes from 182 million mRNA-Seq pair-end 100 bp reads into a total of 15,526 contigs clustered in 4472 unigenes. The transcriptome profile was analyzed for presence of carbohydrate-binding molecules in a variety of architectural contexts. Hemocytes' repertoire of lectin-like proteins bearing conserved carbohydrate-recognition domains (CRDs) is highly diversified, including 11 of 15 lectin families earlier described in animals, as well as the novel members of lectin family found for the first time in mollusc species. The new molluscan lineage-specific domain combinations were confirmed by cloning and sequencing, including the fuco-lectin related molecules (FLReMs) composed of N-terminal region with no sequence homology to any known protein, a middle Fucolectin Tachylectin-4 Pentaxrin (FTP) domain, and a C-terminal epidermal growth factor (EGF) repeat region. The repertoire of lectin-like molecules is discussed in terms of their potential participation in the receptor phase of immune response. In total, immune-associated functions may be attributed to 70 transcripts belonging to 6 lectin families. These lectin-like genes show low overlap between species of invertebrates, suggesting relatively rapid evolution of immune-associated genes in the group. The repertoire provides valuable candidates for further characterization of the gene functions in mollusc immunity. PMID:25451301

  6. Purification, crystallization and preliminary X-ray analysis of the ligand-binding domain of human lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1)

    SciTech Connect

    Ishigaki, Tomoko; Ohki, Izuru; Oyama, Takuji; Machida, Sachiko; Morikawa, Kousuke; Tate, Shin-ichi

    2005-05-01

    Two different fragments of the ligand-binding domain of LOX-1, the major receptor for oxidized low-density lipoprotein (LDL) on endothelial cells, have been crystallized in different forms. Two different fragments of the ligand-binding domain of LOX-1, the major receptor for oxidized low-density lipoprotein (LDL) on endothelial cells, have been crystallized in different forms. One crystal form contains the disulfide-linked dimer, which is the form of the molecule present on the cell surface; the other contains a monomeric form of the receptor that lacks the cysteine residue necessary to form disulfide-linked homodimers. The crystal of the monomeric ligand-binding domain belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 56.79, b = 67.57, c = 79.02 Å. The crystal of the dimeric form belongs to space group C2, with unit-cell parameters a = 70.86, b = 49.56, c = 76.73 Å, β = 98.59°. Data for the dimeric form of the LOX-1 ligand-binding domain have been collected to 2.4 Å. For the monomeric form of the ligand-binding domain, native, heavy-atom derivative and SeMet-derivative crystals have been obtained; their diffraction data have been measured to 3.0, 2.4 and 1.8 Å resolution, respectively.

  7. Cyclic tensile stretch load and oxidized low density lipoprotein synergistically induce lectin-like oxidized ldl receptor-1 in cultured bovine chondrocytes, resulting in decreased cell viability and proteoglycan synthesis.

    PubMed

    Akagi, Masao; Nishimura, Shunji; Yoshida, Kohji; Kakinuma, Takumi; Sawamura, Tatsuya; Munakata, Hiroshi; Hamanishi, Chiaki

    2006-08-01

    Mechanical stimulation is known to be an essential factor in the regulation of cartilage metabolism. We tested the hypothesis that expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) can be modulated by cyclic tensile stretch load in chondrocytes. Cyclic loading of repeated stretch stress at 10 cycles per minute with 10 kPa of stress for 6 h induced expression of LOX-1 to 2.6 times control in cultured bovine articular chondrocytes, equivalent to the addition of 10 microg/mL oxidized low density lipoprotein (ox-LDL) (2.4 times control). Application of the cyclic load to the chondrocytes along with 10 microg/mL ox-LDL resulted in synergistically increased LOX-1 expression to 6.3 times control. Individual application of cyclic loading and 10 microg/mL ox-LDL significantly suppressed chondrocytes viability (84.6% +/- 3.4% and 80.9% +/- 3.2% of control at 24 h, respectively; n = 3; p < 0.05) and proteoglycan synthesis [81.0% +/- 7.1% and 85.7% +/- 5.2% of control at 24 h, respectively; p < 0.05 when compared with 94.6% +/- 4.6% for native-LDL (n = 3)]. Cyclic loading and 10 microg/mL ox-LDL synergistically affected cell viability and proteoglycan synthesis, which were significantly suppressed to 45.6% +/- 4.9% and 48.7% +/- 6.7% of control at 24 h, respectively (n = 3; p < 0.01 when compared with individual application of cyclic loading or 10 microg/mL ox-LDL). In this study, we demonstrated synergistic effects of cyclic tensile stretch load and ox-LDL on cell viability and proteoglycan synthesis in chondrocytes, which may be mediated through enhanced expression of LOX-1 and which has important implications in the progression of cartilage degeneration in osteoarthritis.

  8. The specificity of frutalin lectin using biomembrane models.

    PubMed

    Nobre, Thatyane M; Pavinatto, Felippe J; Cominetti, Márcia R; Selistre de-Araújo, Heloísa S; Zaniquelli, Maria E D; Beltramini, Leila M

    2010-08-01

    Frutalin is a homotetrameric alpha-d-galactose (d-Gal)-binding lectin that activates natural killer cells in vitro and promotes leukocyte migration in vivo. Because lectins are potent lymphocyte stimulators, understanding the interactions that occur between them and cell surfaces can help to the action mechanisms involved in this process. In this paper, we present a detailed investigation of the interactions of frutalin with phospho- and glycolipids using Langmuir monolayers as biomembrane models. The results confirm the specificity of frutalin for d-Gal attached to a biomembrane. Adsorption of frutalin was more efficient for the galactose polar head lipids, in contrast to the one for sulfated galactose, in which a lag time is observed, indicating a rearrangement of the monolayer to incorporate the protein. Regarding ganglioside GM1 monolayers, lower quantities of the protein were adsorbed, probably due to the farther apart position of d-galactose from the interface. Binary mixtures containing galactocerebroside revealed small domains formed at high lipid packing in the presence of frutalin, suggesting that lectin induces the clusterization and the forming of domains in vitro, which may be a form of receptor internalization. This is the first experimental evidence of such lectin effect, and it may be useful to understand the mechanism of action of lectins at the molecular level.

  9. Lectin histochemical studies on the vomeronasal organ of the sheep.

    PubMed

    Ibrahim, Dalia; Nakamuta, Nobuaki; Taniguchi, Kazumi; Taniguchi, Kazuyuki

    2013-01-01

    The vomeronasal organ of sheep was examined using lectin histochemistry in order to compare the types and amounts of the glycoconjugates among various components of the vomeronasal sensory and non-sensory epithelia. In the vomeronasal sensory epithelium, Dolichos biflorus agglutinin (DBA) stained particular cells, located at the same level as the vomeronasal receptor cells, while the distribution, shape and number of the stained cells did not correspond to those of the vomeronasal receptor cells. Datura stramonium lectin (DSL), Concanavalin A (Con A), Phaseolus vulgaris agglutinin-E (PHA-E) and Phaseolus vulgaris agglutinin-L (PHA-L) labeled the basal cells of both vomeronasal sensory and non-sensory epithelia. While, Wheat germ agglutinin (WGA), Succinylated-wheat germ agglutinin (s-WGA), Lycopersicon esculentum lectin (LEL), Solanum tuberosum lectin (STL) and Ricinus communis agglutinin-I (RCA-120) labeled the basal cells of the sensory epithelium, and Bandeiraea simplicifolia lectin-I (BSL-I) stained the basal cells of the non-sensory epithelium, respectively. Seventeen lectins labeled the free border of both vomeronasal sensory and non-sensory epithelia, while Sophora japonica agglutinin (SJA), Jacalin and Pisum sativum agglutinin (PSA) labeled neither free border of the sensory nor that of non-sensory epithelia. The expression pattern of glycoconjugate was similar, but not identical, in the free border between the sensory and non-sensory epithelia. These results indicate that there are dissimilar features in the type and amount of glycoconjugates between the vomeronasal sensory and non-sensory epithelia, and at the same time, among the various cell types either in the vomeronasal sensory or non-sensory epithelium. PMID:23595118

  10. Pattern-recognition receptors in human eosinophils

    PubMed Central

    Kvarnhammar, Anne Månsson; Cardell, Lars Olaf

    2012-01-01

    The pattern-recognition receptor (PRR) family includes Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD) -like receptors (NLRs), RIG-I-like receptors (RLRs), C-type lectin receptors (CLRs) and the receptor for advanced glycation end products (RAGE). They recognize various microbial signatures or host-derived danger signals and trigger an immune response. Eosinophils are multifunctional leucocytes involved in the pathogenesis of several inflammatory processes, including parasitic helminth infection, allergic diseases, tissue injury and tumour immunity. Human eosinophils express several PRRs, including TLR1–5, TLR7, TLR9, NOD1, NOD2, Dectin-1 and RAGE. Receptor stimulation induces survival, oxidative burst, activation of the adhesion system and release of cytokines (interleukin-1β, interleukin-6, tumour necrosis factor-α and granulocyte–macrophage colony-stimulating factor), chemokines (interleukin-8 and growth-related oncogene-α) and cytotoxic granule proteins (eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase and major basic protein). It is also evident that eosinophils play an immunomodulatory role by interacting with surrounding cells. The presence of a broad range of PRRs in eosinophils indicates that they are not only involved in defence against parasitic helminths, but also against bacteria, viruses and fungi. From a clinical perspective, eosinophilic PRRs seem to be involved in both allergic and malignant diseases by causing exacerbations and affecting tumour growth, respectively. PMID:22242941

  11. Pattern-recognition receptors in human eosinophils.

    PubMed

    Kvarnhammar, Anne Månsson; Cardell, Lars Olaf

    2012-05-01

    The pattern-recognition receptor (PRR) family includes Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD) -like receptors (NLRs), RIG-I-like receptors (RLRs), C-type lectin receptors (CLRs) and the receptor for advanced glycation end products (RAGE). They recognize various microbial signatures or host-derived danger signals and trigger an immune response. Eosinophils are multifunctional leucocytes involved in the pathogenesis of several inflammatory processes, including parasitic helminth infection, allergic diseases, tissue injury and tumour immunity. Human eosinophils express several PRRs, including TLR1-5, TLR7, TLR9, NOD1, NOD2, Dectin-1 and RAGE. Receptor stimulation induces survival, oxidative burst, activation of the adhesion system and release of cytokines (interleukin-1β, interleukin-6, tumour necrosis factor-α and granulocyte-macrophage colony-stimulating factor), chemokines (interleukin-8 and growth-related oncogene-α) and cytotoxic granule proteins (eosinophil cationic protein, eosinophil-derived neurotoxin, eosinophil peroxidase and major basic protein). It is also evident that eosinophils play an immunomodulatory role by interacting with surrounding cells. The presence of a broad range of PRRs in eosinophils indicates that they are not only involved in defence against parasitic helminths, but also against bacteria, viruses and fungi. From a clinical perspective, eosinophilic PRRs seem to be involved in both allergic and malignant diseases by causing exacerbations and affecting tumour growth, respectively.

  12. Endothelial C-type natriuretic peptide maintains vascular homeostasis.

    PubMed

    Moyes, Amie J; Khambata, Rayomand S; Villar, Inmaculada; Bubb, Kristen J; Baliga, Reshma S; Lumsden, Natalie G; Xiao, Fang; Gane, Paul J; Rebstock, Anne-Sophie; Worthington, Roberta J; Simone, Michela I; Mota, Filipa; Rivilla, Fernando; Vallejo, Susana; Peiró, Concepción; Sánchez Ferrer, Carlos F; Djordjevic, Snezana; Caulfield, Mark J; MacAllister, Raymond J; Selwood, David L; Ahluwalia, Amrita; Hobbs, Adrian J

    2014-09-01

    The endothelium plays a fundamental role in maintaining vascular homeostasis by releasing factors that regulate local blood flow, systemic blood pressure, and the reactivity of leukocytes and platelets. Accordingly, endothelial dysfunction underpins many cardiovascular diseases, including hypertension, myocardial infarction, and stroke. Herein, we evaluated mice with endothelial-specific deletion of Nppc, which encodes C-type natriuretic peptide (CNP), and determined that this mediator is essential for multiple aspects of vascular regulation. Specifically, disruption of CNP leads to endothelial dysfunction, hypertension, atherogenesis, and aneurysm. Moreover, we identified natriuretic peptide receptor-C (NPR-C) as the cognate receptor that primarily underlies CNP-dependent vasoprotective functions and developed small-molecule NPR-C agonists to target this pathway. Administration of NPR-C agonists promotes a vasorelaxation of isolated resistance arteries and a reduction in blood pressure in wild-type animals that is diminished in mice lacking NPR-C. This work provides a mechanistic explanation for genome-wide association studies that have linked the NPR-C (Npr3) locus with hypertension by demonstrating the importance of CNP/NPR-C signaling in preserving vascular homoeostasis. Furthermore, these results suggest that the CNP/NPR-C pathway has potential as a disease-modifying therapeutic target for cardiovascular disorders.

  13. Biological Modulation by Lectins and Their Ligands in Tumor Progression and Metastasis

    PubMed Central

    Nakahara, Susumu; Raz, Avraham

    2013-01-01

    Lectins are a group of specific proteins that preferentially bind to carbohydrates inside and outside cells. To date, an increasing number of animal lectins have been found and categorized into several families in terms of the significant primary structural homology, while the classification is not always straightforward. These lectins can exert immense biological functions mainly through their specific carbohydrate-protein interactions in a variety of situations. In cancer biology, aberrant glycosylation changes on many glycoproteins and glycolipids are often observed and numerous experimental evidences have revealed that these structural changes are related to tumor malignancy. Galectins, which are broadly expressed animal lectins, can play crucial biological roles in tumor cell-cell or cell-matrix interactions through their binding activities to the tumor cell surface carbohydrate determinants. Certain galectin family proteins have also shown to affect tumor cell survival, signal transduction, and proliferation mainly inside the cell. Selectins, which are one of the C-type lectins and expressed leukocytes and/or vascular endothelium, can also play an immense role in tumor cell adhesion and invasion. In addition, certain annexin family proteins, which are originally known as phospholipid binding proteins, have been revealed to possess the carbohydrate binding activity, and these novel functions in tumors are being unveiled. Understanding how carbohydrate-protein interactions function in tumor cells will be one of the important goals in cancer research. This review focuses on the role of these lectins and their ligands in cancer progression and metastasis. PMID:18220503

  14. Use of lectins in immunohematology

    PubMed Central

    Gorakshakar, Ajit C.; Ghosh, Kanjaksha

    2016-01-01

    Lectins are carbohydrate binding proteins present in seeds of many plants, especially corals and beans, in fungi and bacteria, and in animals. Apart from their hemagglutinating property, a wide range of functions have been attributed to them. Their importance in the area of immunohematology is immense. They are used to detect specific red cell antigens, to activate different types of lymphocytes, in order to resolve problems related to polyagglutination and so on. The introduction of advanced biotechnological tools generates new opportunities to exploit the properties of lectins, which were not used earlier. Stem cell research is a very important area in transplant medicine. Certain lectins detect surface markers of stem cell. Hence, they are used to understand the developmental biology of stem cells. The role of various lectins in the areas of transfusion and transplant medicine is discussed in detail in this review. PMID:27011665

  15. A review of fish lectins.

    PubMed

    Ng, Tzi Bun; Fai Cheung, Randy Chi; Wing Ng, Charlene Cheuk; Fang, Evandro Fei; Wong, Jack Ho

    2015-01-01

    Lectins have been reported from various tissues of a diversity of fish species including Japanese eel, conger eel, electric eel, bighead carp, gibel carp, grass carp, Arabian Gulf catfish, channel catfish, blue catfish, catfish, pike perch, perch, powan, zebrafish, toxic moray, cobia fish, steelhead trout, Japanese trout, Atlantic salmon, chinook salmon, olive rainbow smelt, rainbow smelt, white-spotted charr, tilapia, blue gourami, ayu, Potca fish, Spanish mackerel, gilt head bream, tench, roach, rudd, common skate, and sea lamprey. The tissues from which the lectins were isolated comprise gills, eggs, electric organ, stomach, intestine, and liver. Lectins have also been isolated from skin, mucus serum, and plasma. The lectins differ in molecular weight, number of subunits, glycosylation, sugar binding specificity and amino acid sequence. Their activities include antimicrobial, antitumor, immunoregulatory and a role in development. PMID:25929869

  16. Use of lectins in immunohematology.

    PubMed

    Gorakshakar, Ajit C; Ghosh, Kanjaksha

    2016-01-01

    Lectins are carbohydrate binding proteins present in seeds of many plants, especially corals and beans, in fungi and bacteria, and in animals. Apart from their hemagglutinating property, a wide range of functions have been attributed to them. Their importance in the area of immunohematology is immense. They are used to detect specific red cell antigens, to activate different types of lymphocytes, in order to resolve problems related to polyagglutination and so on. The introduction of advanced biotechnological tools generates new opportunities to exploit the properties of lectins, which were not used earlier. Stem cell research is a very important area in transplant medicine. Certain lectins detect surface markers of stem cell. Hence, they are used to understand the developmental biology of stem cells. The role of various lectins in the areas of transfusion and transplant medicine is discussed in detail in this review.

  17. Characterisation of Jack fruit lectin.

    PubMed

    Arslan, M I; Chulavatnatol, M

    2000-04-01

    Jack fruit (Artocarpus Heterophyllus) seed extract contains a lectin termed Jack fruit lectin (JFL) which possesses diversed biological properties. A detailed analysis of its properties has been lacking. The present investigation was initiated to study the detail properties of JFL. After extraction and purification on affigel galactosamine-agarose column, JFL was subjected to ND-PAGE. Several different charged species from ND-PAGE upon SDS-PAGE gave rise to two dissimilar trimeric subunit at 12.5 and 15.0 KDa and retain biological activity. It was possible to elute the subunit bands separately from polyacrylamide gel to investigate their biological activity. Each subunit was found to be retained the lectin activity. Agglutinating activity of smaller subunit was found to be more, may be due to the greater amount of the subunit. This also suggests that each unit of trimeric JFL have similar lectin activity.

  18. Role of Lectins in Plant-Microorganism Interactions

    PubMed Central

    Bhuvaneswari, T. V.; Bauer, Wolfgang D.

    1978-01-01

    The influence of rhizosphere/rhizoplane culture conditions on the ability of various rhizobia to bind soybean seed lectin (SBL) was examined. Eleven strains of the soybean symbiont, Rhizobium japonicum, and six strains of various heterologous Rhizobium species were cultured in root exudate of soybean (Glycine max [L.] Merr.) and in association with roots of soybean seedlings which were growing either hydroponically or in montmorillonite clay soil amendment (Turface). All 11 of the R. japonicum strains developed biochemically specific receptors for the lectin when cultured under these conditions, whereas six of the 11 did not develop such receptors when cultured in synthetic salts medium. Two cowpea strains also developed receptors for SBL. The other four heterologous strains of rhizobia gave no evidence of biochemically specific SBL binding in either synthetic salts media or rhizosphere/rhizoplane cultures. These results demonstrate that the environment provided by plant roots is an important factor in the development of specific lectin receptors on the cell surface of R. japonicum. PMID:16660472

  19. Pattern recognition receptors in antifungal immunity.

    PubMed

    Plato, Anthony; Hardison, Sarah E; Brown, Gordon D

    2015-03-01

    Receptors of the innate immune system are the first line of defence against infection, being able to recognise and initiate an inflammatory response to invading microorganisms. The Toll-like (TLR), NOD-like (NLR), RIG-I-like (RLR) and C-type lectin-like receptors (CLR) are four receptor families that contribute to the recognition of a vast range of species, including fungi. Many of these pattern recognition receptors (PRRs) are able to initiate innate immunity and polarise adaptive responses upon the recognition of fungal cell wall components and other conserved molecular patterns, including fungal nucleic acids. These receptors induce effective mechanisms of fungal clearance in normal hosts, but medical interventions, immunosuppression or genetic predisposition can lead to susceptibility to fungal infections. In this review, we highlight the importance of PRRs in fungal infection, specifically CLRs, which are the major PRR involved. We will describe specific PRRs in detail, the importance of receptor collaboration in fungal recognition and clearance, and describe how genetic aberrations in PRRs can contribute to disease pathology.

  20. The macrophage galactose-type lectin-1 (MGL1) recognizes Taenia crassiceps antigens, triggers intracellular signaling, and is critical for resistance to this infection.

    PubMed

    Montero-Barrera, Daniel; Valderrama-Carvajal, Héctor; Terrazas, César A; Rojas-Hernández, Saúl; Ledesma-Soto, Yadira; Vera-Arias, Laura; Carrasco-Yépez, Maricela; Gómez-García, Lorena; Martínez-Saucedo, Diana; Becerra-Díaz, Mireya; Terrazas, Luis I

    2015-01-01

    C-type lectins are multifunctional sugar-binding molecules expressed on dendritic cells (DCs) and macrophages that internalize antigens for processing and presentation. Macrophage galactose-type lectin 1 (MGL1) recognizes glycoconjugates expressing Lewis X structures which contain galactose residues, and it is selectively expressed on immature DCs and macrophages. Helminth parasites contain large amounts of glycosylated components, which play a role in the immune regulation induced by such infections. Macrophages from MGL1(-/-) mice showed less binding ability toward parasite antigens than their wild-type (WT) counterparts. Exposure of WT macrophages to T. crassiceps antigens triggered tyrosine phosphorylation signaling activity, which was diminished in MGL1(-/-) macrophages. Following T. crassiceps infection, MGL1(-/-) mice failed to produce significant levels of inflammatory cytokines early in the infection compared to WT mice. In contrast, MGL1(-/-) mice developed a Th2-dominant immune response that was associated with significantly higher parasite loads, whereas WT mice were resistant. Flow cytometry and RT-PCR analyses showed overexpression of the mannose receptors, IL-4Rα, PDL2, arginase-1, Ym1, and RELM-α on MGL1(-/-) macrophages. These studies indicate that MGL1 is involved in T. crassiceps recognition and subsequent innate immune activation and resistance.

  1. The Macrophage Galactose-Type Lectin-1 (MGL1) Recognizes Taenia crassiceps Antigens, Triggers Intracellular Signaling, and Is Critical for Resistance to This Infection

    PubMed Central

    Montero-Barrera, Daniel; Valderrama-Carvajal, Héctor; Terrazas, César A.; Rojas-Hernández, Saúl; Ledesma-Soto, Yadira; Vera-Arias, Laura; Carrasco-Yépez, Maricela; Gómez-García, Lorena; Martínez-Saucedo, Diana; Becerra-Díaz, Mireya; Terrazas, Luis I.

    2015-01-01

    C-type lectins are multifunctional sugar-binding molecules expressed on dendritic cells (DCs) and macrophages that internalize antigens for processing and presentation. Macrophage galactose-type lectin 1 (MGL1) recognizes glycoconjugates expressing Lewis X structures which contain galactose residues, and it is selectively expressed on immature DCs and macrophages. Helminth parasites contain large amounts of glycosylated components, which play a role in the immune regulation induced by such infections. Macrophages from MGL1−/− mice showed less binding ability toward parasite antigens than their wild-type (WT) counterparts. Exposure of WT macrophages to T. crassiceps antigens triggered tyrosine phosphorylation signaling activity, which was diminished in MGL1−/− macrophages. Following T. crassiceps infection, MGL1−/− mice failed to produce significant levels of inflammatory cytokines early in the infection compared to WT mice. In contrast, MGL1−/− mice developed a Th2-dominant immune response that was associated with significantly higher parasite loads, whereas WT mice were resistant. Flow cytometry and RT-PCR analyses showed overexpression of the mannose receptors, IL-4Rα, PDL2, arginase-1, Ym1, and RELM-α on MGL1−/− macrophages. These studies indicate that MGL1 is involved in T. crassiceps recognition and subsequent innate immune activation and resistance. PMID:25664320

  2. IgG4 anti-phospholipase A2 receptor might activate lectin and alternative complement pathway meanwhile in idiopathic membranous nephropathy: an inspiration from a cross-sectional study.

    PubMed

    Yang, Yang; Wang, Chao; Jin, Liping; He, Fagui; Li, Changchun; Gao, Qingman; Chen, Guanglei; He, Zhijun; Song, Minghui; Zhou, Zhuliang; Shan, Fujun; Qi, Ka; Ma, Lu

    2016-08-01

    The deposition of IgG4 of antibodies against phospholipase A2 receptor (anti-PLA2R) is predominating in the kidneys of patients with idiopathic membranous nephropathy, while its predictive value has not been determined. It was a retrospective study, and 438 patients were included. Serum samples of two time points [before intervention (baseline) and after 1.5-year treatment (endpoint)] were detected for total and IgG4 anti-PLA2R. IgG4 <0.26 RU/mL or total <20 RU/mL was considered as seronegativity. Bi-positivity/bi-negativity was defined when patients'antibodies were found positive or negative both at the baseline and endpoint. Completed remission (CR) was a major clinical outcome. A series of complement ingredients (MASP-1/2, MBL, C3a, C5a, Factor B, Ba, Bb and C5b-9) were measured in the patients of bi-positivity and bi-negativity: (1) meta-analysis based on six papers conducted seropositivity of anti-PLA2R was a useful predictor for achieving CR, but there was a high heterogeneity; (2) there was significant correlation between the baseline and decrease in IgG4 subclass and the achievement of CR; (3) bi-negativity of IgG4 has a high accuracy of predicting CR compared with total antibodies; (4) in patients of bi-positivity, those achieving CR showed lower MASP-1/2, MBL, C3a, C5a, FB, Ba and Bb than patients failing to achieve CR; (5) the titers of endpoint and decrease in Ba and Bb were associated with improvement of 24 h-UP in those of bi-positivity; and (6) the decrease in Ba was a significant factor for achieving CR in those of bi-positivity. Continuous IgG4 negativity was a useful tool to predict the achievement of CR; however, in patients of continuous IgG4 positivity, those with lower activation of lectin and alternative pathways would still more probably achieve CR.

  3. Thermodynamic, kinetic, and electron microscopy studies of concanavalin A and Dioclea grandiflora lectin cross-linked with synthetic divalent carbohydrates.

    PubMed

    Dam, Tarun K; Oscarson, Stefan; Roy, René; Das, Sanjoy K; Pagé, Daniel; Macaluso, Frank; Brewer, C Fred

    2005-03-11

    The jack bean lectin concanavalin A (ConA) and the Dioclea grandiflora lectin (DGL) are highly homologous Man/Glc-specific members of the Diocleinae subtribe. Both lectins bind, cross-link, and precipitate with carbohydrates possessing multiple terminal nonreducing Man residues. The present study investigates the binding and cross-linking interactions of ConA and DGL with a series of synthetic divalent carbohydrates that possess spacer groups with increasing flexibility and length between terminal alpha-mannopyranoside residues. Isothermal titration microcalorimetry was used to determine the thermodynamics of binding of the two lectins to the divalent analogs, and kinetic light scattering and electron microscopy studies were used to characterize the cross-linking interactions of the lectins with the carbohydrates. The results demonstrated that divalent analogs with flexible spacer groups between the two terminal Man residues possess higher affinities for the two lectins as compared with those with inflexible spacer groups. Furthermore, despite their high degree of homology, ConA and DGL exhibit differences in their kinetics of cross-linking and precipitation with the divalent analogs. Electron microscopy shows the loss of organized cross-linked lattices of the two lectins with analogs possessing increased distance between the terminal Man residues. The loss of lattice patterns with the analogs is distinct for each lectin. These results have important implications for the interactions of lectins with multivalent carbohydrate receptors in biological systems.

  4. Noncovalent PEGylation via Lectin-Glycopolymer Interactions.

    PubMed

    Antonik, Paweł M; Eissa, Ahmed M; Round, Adam R; Cameron, Neil R; Crowley, Peter B

    2016-08-01

    PEGylation, the covalent modification of proteins with polyethylene glycol, is an abundantly used technique to improve the pharmacokinetics of therapeutic proteins. The drawback with this methodology is that the covalently attached PEG can impede the biological activity (e.g., reduced receptor-binding capacity). Protein therapeutics with "disposable" PEG modifiers have potential advantages over the current technology. Here, we show that a protein-polymer "Medusa complex" is formed by the combination of a hexavalent lectin with a glycopolymer. Using NMR spectroscopy, small-angle X-ray scattering (SAXS), size exclusion chromatography, and native gel electrophoresis it was demonstrated that the fucose-binding lectin RSL and a fucose-capped polyethylene glycol (Fuc-PEG) form a multimeric assembly. All of the experimental methods provided evidence of noncovalent PEGylation with a concomitant increase in molecular mass and hydrodynamic radius. The affinity of the protein-polymer complex was determined by ITC and competition experiments to be in the micromolar range, suggesting that such systems have potential biomedical applications. PMID:27403588

  5. Endothelial C-type natriuretic peptide maintains vascular homeostasis

    PubMed Central

    Moyes, Amie J.; Khambata, Rayomand S.; Villar, Inmaculada; Bubb, Kristen J.; Baliga, Reshma S.; Lumsden, Natalie G.; Xiao, Fang; Gane, Paul J.; Rebstock, Anne-Sophie; Worthington, Roberta J.; Simone, Michela I.; Mota, Filipa; Rivilla, Fernando; Vallejo, Susana; Peiró, Concepción; Sánchez Ferrer, Carlos F.; Djordjevic, Snezana; Caulfield, Mark J.; MacAllister, Raymond J.; Selwood, David L.; Ahluwalia, Amrita; Hobbs, Adrian J.

    2014-01-01

    The endothelium plays a fundamental role in maintaining vascular homeostasis by releasing factors that regulate local blood flow, systemic blood pressure, and the reactivity of leukocytes and platelets. Accordingly, endothelial dysfunction underpins many cardiovascular diseases, including hypertension, myocardial infarction, and stroke. Herein, we evaluated mice with endothelial-specific deletion of Nppc, which encodes C-type natriuretic peptide (CNP), and determined that this mediator is essential for multiple aspects of vascular regulation. Specifically, disruption of CNP leads to endothelial dysfunction, hypertension, atherogenesis, and aneurysm. Moreover, we identified natriuretic peptide receptor–C (NPR-C) as the cognate receptor that primarily underlies CNP-dependent vasoprotective functions and developed small-molecule NPR-C agonists to target this pathway. Administration of NPR-C agonists promotes a vasorelaxation of isolated resistance arteries and a reduction in blood pressure in wild-type animals that is diminished in mice lacking NPR-C. This work provides a mechanistic explanation for genome-wide association studies that have linked the NPR-C (Npr3) locus with hypertension by demonstrating the importance of CNP/NPR-C signaling in preserving vascular homoeostasis. Furthermore, these results suggest that the CNP/NPR-C pathway has potential as a disease-modifying therapeutic target for cardiovascular disorders. PMID:25105365

  6. A Novel Bifunctional Hybrid with Marine Bacterium Alkaline Phosphatase and Far Eastern Holothurian Mannan-Binding Lectin Activities

    PubMed Central

    Balabanova, Larissa; Golotin, Vasily; Kovalchuk, Svetlana; Bulgakov, Alexander; Likhatskaya, Galina; Son, Oksana; Rasskazov, Valery

    2014-01-01

    A fusion between the genes encoding the marine bacterium Cobetia marina alkaline phosphatase (CmAP) and Far Eastern holothurian Apostichopus japonicus mannan-binding C-type lectin (MBL-AJ) was performed. Expression of the fusion gene in E. coli cells resulted in yield of soluble recombinant chimeric protein CmAP/MBL-AJ with the high alkaline phosphatase activity and specificity of the lectin MBL-AJ. The bifunctional hybrid CmAP/MBL-AJ was produced as a dimer with the molecular mass of 200 kDa. The CmAP/MBL-AJ dimer model showed the two-subunit lectin part that is associated with two molecules of alkaline phosphatase functioning independently from each other. The highly active CmAP label genetically linked to MBL-AJ has advantaged the lectin-binding assay in its sensitivity and time. The double substitution A156N/F159K in the lectin domain of CmAP/MBL-AJ has enhanced its lectin activity by 25±5%. The bifunctional hybrid holothurian's lectin could be promising tool for developing non-invasive methods for biological markers assessment, particularly for improving the MBL-AJ-based method for early detection of a malignant condition in cervical specimens. PMID:25397876

  7. Pattern recognition receptors and central nervous system repair.

    PubMed

    Kigerl, Kristina A; de Rivero Vaccari, Juan Pablo; Dietrich, W Dalton; Popovich, Phillip G; Keane, Robert W

    2014-08-01

    Pattern recognition receptors (PRRs) are part of the innate immune response and were originally discovered for their role in recognizing pathogens by ligating specific pathogen associated molecular patterns (PAMPs) expressed by microbes. Now the role of PRRs in sterile inflammation is also appreciated, responding to endogenous stimuli referred to as "damage associated molecular patterns" (DAMPs) instead of PAMPs. The main families of PRRs include Toll-like receptors (TLRs), Nod-like receptors (NLRs), RIG-like receptors (RLRs), AIM2-like receptors (ALRs), and C-type lectin receptors. Broad expression of these PRRs in the CNS and the release of DAMPs in and around sites of injury suggest an important role for these receptor families in mediating post-injury inflammation. Considerable data now show that PRRs are among the first responders to CNS injury and activation of these receptors on microglia, neurons, and astrocytes triggers an innate immune response in the brain and spinal cord. Here we discuss how the various PRR families are activated and can influence injury and repair processes following CNS injury.

  8. Antinutritional properties of plant lectins.

    PubMed

    Vasconcelos, Ilka M; Oliveira, José Tadeu A

    2004-09-15

    Lectins are carbohydrate binding (glyco)proteins which are ubiquitous in nature. In plants, they are distributed in various families and hence ingested daily in appreciable amounts by both humans and animals. One of the most nutritionally important features of plant lectins is their ability to survive digestion by the gastrointestinal tract of consumers. This allows the lectins to bind to membrane glycosyl groups of the cells lining the digestive tract. As a result of this interaction a series of harmful local and systemic reactions are triggered placing this class of molecules as antinutritive and/or toxic substances. Locally, they can affect the turnover and loss of gut epithelial cells, damage the luminal membranes of the epithelium, interfere with nutrient digestion and absorption, stimulate shifts in the bacterial flora and modulate the immune state of the digestive tract. Systemically, they can disrupt lipid, carbohydrate and protein metabolism, promote enlargement and/or atrophy of key internal organs and tissues and alter the hormonal and immunological status. At high intakes, lectins can seriously threaten the growth and health of consuming animals. They are also detrimental to numerous insect pests of crop plants although less is presently known about their insecticidal mechanisms of action. This current review surveys the recent knowledge on the antinutritional/toxic effects of plant lectins on higher animals and insects. PMID:15302522

  9. Lectin microarrays for glycomic analysis.

    PubMed

    Gupta, Garima; Surolia, Avadhesha; Sampathkumar, Srinivasa-Gopalan

    2010-08-01

    Glycomics is the study of comprehensive structural elucidation and characterization of all glycoforms found in nature and their dynamic spatiotemporal changes that are associated with biological processes. Glycocalyx of mammalian cells actively participate in cell-cell, cell-matrix, and cell-pathogen interactions, which impact embryogenesis, growth and development, homeostasis, infection and immunity, signaling, malignancy, and metabolic disorders. Relative to genomics and proteomics, glycomics is just growing out of infancy with great potential in biomedicine for biomarker discovery, diagnosis, and treatment. However, the immense diversity and complexity of glycan structures and their multiple modes of interactions with proteins pose great challenges for development of analytical tools for delineating structure function relationships and understanding glyco-code. Several tools are being developed for glycan profiling based on chromatography, mass spectrometry, glycan microarrays, and glyco-informatics. Lectins, which have long been used in glyco-immunology, printed on a microarray provide a versatile platform for rapid high throughput analysis of glycoforms of biological samples. Herein, we summarize technological advances in lectin microarrays and critically review their impact on glycomics analysis. Challenges remain in terms of expansion to include nonplant derived lectins, standardization for routine clinical use, development of recombinant lectins, and exploration of plant kingdom for discovery of novel lectins. PMID:20726799

  10. Lectin microarrays for glycomic analysis.

    PubMed

    Gupta, Garima; Surolia, Avadhesha; Sampathkumar, Srinivasa-Gopalan

    2010-08-01

    Glycomics is the study of comprehensive structural elucidation and characterization of all glycoforms found in nature and their dynamic spatiotemporal changes that are associated with biological processes. Glycocalyx of mammalian cells actively participate in cell-cell, cell-matrix, and cell-pathogen interactions, which impact embryogenesis, growth and development, homeostasis, infection and immunity, signaling, malignancy, and metabolic disorders. Relative to genomics and proteomics, glycomics is just growing out of infancy with great potential in biomedicine for biomarker discovery, diagnosis, and treatment. However, the immense diversity and complexity of glycan structures and their multiple modes of interactions with proteins pose great challenges for development of analytical tools for delineating structure function relationships and understanding glyco-code. Several tools are being developed for glycan profiling based on chromatography, mass spectrometry, glycan microarrays, and glyco-informatics. Lectins, which have long been used in glyco-immunology, printed on a microarray provide a versatile platform for rapid high throughput analysis of glycoforms of biological samples. Herein, we summarize technological advances in lectin microarrays and critically review their impact on glycomics analysis. Challenges remain in terms of expansion to include nonplant derived lectins, standardization for routine clinical use, development of recombinant lectins, and exploration of plant kingdom for discovery of novel lectins.

  11. Role of the lectin complement pathway in kidney transplantation.

    PubMed

    Farrar, Conrad A; Zhou, Wuding; Sacks, Steven H

    2016-10-01

    In the last 15 years two major advances in the role of complement in the kidney transplant have come about. The first is that ischaemia reperfusion injury and its profound effect on transplant outcome is dependent on the terminal product of complement activation, C5b-9. The second key observation relates to the function of the small biologically active fragments C3a and C5a released by complement activation in increasing antigen presentation and priming the T cell response that results in transplant rejection. In both cases local synthesis of C3 principally by the renal tubule cells plays an essential role that overshadows the role of the circulating pool of C3 generated largely by hepatocyte synthesis. More recent efforts have investigated the molecules expressed by renal tissue that can trigger complement activation. These have revealed a prominent effect of collectin-11 (CL-11), a soluble C-type lectin that is expressed in renal tissue and aligns with its major ligand L-fucose at sites of complement activation following ischaemic stress. Biochemical studies have shown that interaction between CL-11 and L-fucose results in complement activation by the lectin complement pathway, precisely targeting the innate immune response to the ischaemic tubule surface. Therapeutic approaches to reduce inflammatory and immune stimulation in ischaemic kidney have so far targeted C3 or its activation products and several are in clinical trials. The finding that lectin-fucose interaction is an important trigger of lectin pathway complement activation within the donor organ opens up further therapeutic targets where intervention could protect the donor kidney against complement. PMID:27286717

  12. Diagnostic value of interactions between members of the family Neisseriaceae and lectins.

    PubMed Central

    Doyle, R J; Nedjat-Haiem, F; Keller, K F; Frasch, C E

    1984-01-01

    The lectin slide agglutination test for Neisseria gonorrhoeae has been modified and improved. Results show that wheat germ agglutinin and soybean lectin agglutinate 100% (193 of 193 tested) of clinical isolates of N. gonorrhoeae. Lectin-reactive meningococci can be readily identified by the hydrolysis of gamma-glutamyl-beta-naphthylamide. Branhamella catarrhalis, Neisseria lactamica, Neisseria sicca, Neisseria subflava, Neisseria perflava, and meningococcal serogroups A, B, C, X, Y, and Z do not interfere with the positive identification of N. gonorrhoeae. The frequently encountered problem of autoagglutination of members of the family Neisseriaceae may be circumvented by a short treatment of cellular suspensions with DNase. Based on agglutination assays, the enzyme treatment did not result in a loss of wheat germ agglutinin receptors from the bacteria. The lectin agglutination test, coupled with the gamma-glutamyl aminopeptidase assay, is proposed as a rapid and accurate means of identifying clinical isolates of gonococci. PMID:6546936

  13. Purification of the rice embryo lectin and its binding to nitrogen-fixing bacteria from the rhizosphere of rice.

    PubMed

    Tabary, F; Balandreau, J; Bourrillon, R

    1984-03-15

    A lectin was purified from rice embryos by aqueous acid extraction of crude embryo powder, followed by ammonium sulfate precipitation, affinity chromatography on agarose p-aminophenyl-beta-D-N-acetylglucosamine and gel-filtration on AcA 54. Its homogeneity was checked by polyacrylamide gel electrophoresis, gel-filtration and immunological methods. The hemagglutinating activity of the purified rice lectin was 0.02 micrograms/ml. This lectin labelled with [14C] acetic anhydride was shown to interact in vitro with different bacteria isolated from the rhizosphere of rice. The most efficient binding was obtained with Beijerinckia V.. The affinity constant Ka was (1.04 +/- 0.30) X 10(7) M-1 and each bacterium contained 1660 +/- 150 lectin receptor sites. In contrast, no interaction between bacteria isolated from the rhizosphere of maize or E. coli K 12 and rice lectin was evidenced. PMID:6712642

  14. Cflec-5, a pattern recognition receptor in scallop Chlamys farreri agglutinating yeast Pichia pastoris.

    PubMed

    Zhang, Huan; Kong, Pengfei; Wang, Lingling; Zhou, Zhi; Yang, Jialong; Zhang, Ying; Qiu, Limei; Song, Linsheng

    2010-07-01

    C-type lectins are a superfamily of carbohydrate-recognition proteins which play crucial roles as pattern recognition receptors (PRRs) in the innate immunity. In this study, the full-length cDNA of a C-type lectin was cloned from scallop Chlamys farreri (designated as Cflec-5) by expression sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE) approach. The full-length cDNA of Cflec-5 was of 1412 bp. The open reading frame encoded a polypeptide of 153 amino acids, including a signal sequence and a conserved carbohydrate-recognition domain with the EPN motif determining the mannose-binding specificity. The deduced amino acid sequence of Cflec-5 showed high similarity to members of C-type lectin superfamily. The quantitative real-time PCR was performed to investigate the tissue distribution of Cflec-5 mRNA and its temporal expression profiles in hemocytes post pathogen-associated molecular patterns (PAMPs) stimulation. In healthy scallops, the Cflec-5 mRNA was mainly detected in gill and mantle, and marginally in other tissues. The mRNA expression of Cflec-5 could be significantly induced by lipopolysaccharide (LPS) and glucan stimulation and reached the maximum level at 6 h and 12 h, respectively. But its expression level did not change significantly during peptidoglycan (PGN) stimulation. The function of Cflec-5 was investigated by recombination and expression of the cDNA fragment encoding its mature peptide in Escherichia coli Rosetta Gami (DE3). The recombinant Cflec-5 agglutinated Pichia pastoris in a calcium-independent way. The agglutinating activity could be inhibited by d-mannose, LPS and glucan, but not by d-galactose or PGN. These results collectively suggested that Cflec-5 was involved in the innate immune response of scallops and might contribute to nonself-recognition through its interaction with various PAMPs. PMID:20211738

  15. Macrophage Galactose-Type Lectin-1 Deficiency Is Associated with Increased Neutrophilia and Hyperinflammation in Gram-Negative Pneumonia.

    PubMed

    Jondle, Christopher N; Sharma, Atul; Simonson, Tanner J; Larson, Benjamin; Mishra, Bibhuti B; Sharma, Jyotika

    2016-04-01

    C-type lectin receptors (CLRs), the carbohydrate-recognizing molecules, orchestrate host immune response in homeostasis and in inflammation. In the present study we examined the function of macrophage galactose-type lectin-1 (MGL1), a mammalian CLR, in pneumonic sepsis, a deadly immune disorder frequently associated with a nonresolving hyperinflammation. In a murine model of pneumonic sepsis using pulmonary infection with Klebsiella pneumoniae, the expression of MGL1 was upregulated in the lungs of K. pneumoniae-infected mice, and the deficiency of this CLR in MGL1(-/-) mice resulted in significantly increased mortality to infection than in the MGL1-sufficient wild-type mice, despite a similar bacterial burden. The phagocytic cells from MGL1(-/-) mice did not exhibit any defects in bacterial uptake and intracellular killing and were fully competent in neutrophil extracellular trap formation, a recently identified extracellular killing modality of neutrophils. Instead, the increased susceptibility of MGL1(-/-) mice seemed to correlate with severe lung pathology, indicating that MGL1 is required for resolution of pulmonary inflammation. Indeed, the MGL1(-/-) mice exhibited a hyperinflammatory response, massive pulmonary neutrophilia, and an increase in neutrophil-associated immune mediators. Concomitantly, MGL1-deficient neutrophils exhibited an increased influx in pneumonic lungs of K. pneumoniae-infected mice. Taken together, these results show a previously undetermined role of MGL1 in controlling neutrophilia during pneumonic infection, thus playing an important role in resolution of inflammation. To our knowledge, this is the first study depicting a protective function of MGL1 in an acute pneumonic bacterial infection. PMID:26912318

  16. Isolation, functional, and partial biochemical characterization of galatrox, an acidic lectin from Bothrops atrox snake venom.

    PubMed

    Mendonça-Franqueiro, Elaine de Paula; Alves-Paiva, Raquel de Melo; Sartim, Marco Aurélio; Callejon, Daniel Roberto; Paiva, Helder Henrique; Antonucci, Gilmara Ausech; Rosa, José César; Cintra, Adélia Cristina Oliveira; Franco, João José; Arantes, Eliane Candiani; Dias-Baruffi, Marcelo; Sampaio, Suely Vilela

    2011-03-01

    Snake venom lectins have been studied in regard to their chemical structure and biological functions. However, little is known about lectins isolated from Bothrops atrox snake venom. We report here the isolation and partial functional and biochemical characterization of an acidic glycan-binding protein called galatrox from this venom. This lectin was purified by affinity chromatography using a lactosyl-sepharose column, and its homogeneity and molecular mass were evaluated by high-performance liquid chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The purified galatrox was homogeneous and characterized as an acidic protein (pI 5.2) with a monomeric and dimeric molecular mass of 16.2 and 32.5 kDa, respectively. Alignment of N-terminal and internal amino acid sequences of galatrox indicated that this protein exhibits high homology to other C-type snake venom lectins. Galatrox showed optimal hemagglutinating activity at a concentration of 100 μg/ml and this effect was drastically inhibited by lactose, ethylenediaminetetraacetic acid, and heating, which confirmed galatrox's lectin activity. While galatrox failed to induce the same level of paw edema or mast cell degranulation as B. atrox crude venom, galatrox did alter cellular viability, which suggested that galatrox might contribute to venom toxicity by directly inducing cell death. PMID:21297119

  17. Ly49 receptors: evolution, genetic diversity, and impact on immunity.

    PubMed

    Rahim, Mir Munir A; Makrigiannis, Andrew P

    2015-09-01

    Natural killer (NK) cells express cell surface receptors that recognize class I major histocompatibility complex (MHC-I) molecules to distinguish between healthy and unhealthy cells. The multigenic and polymorphic nature of the MHC-I genes has influenced the convergent evolution of similarly polymorphic and diversified NK cell receptor families: the C-type lectin-like Ly49 receptors in mice, and the killer cell immunoglobulin-like receptors (KIRs) in humans. Although structurally distinct, both receptor families have similar functions in terms of MHC-I recognition and downstream signal transduction, and they regulate multiple aspects of NK cell biology during development and after maturation as fully differentiated and functionally competent cells. The Ly49 gene locus has undergone rapid, lineage-specific expansions and contractions resulting in multiple distinct haplotypes of variable gene number, allelic diversity, and MHC-I ligand specificity. This in turn has influenced the type and degree of Ly49 receptor expression on NK cells, and their contribution to immunity in different mouse strains. In this review, we have attempted to describe the evolutionary processes that have shaped strain-specific Ly49 receptor repertoires, and their impact on NK cell functions during health and disease.

  18. Role of Lectins in Plant-Microorganism Interactions

    PubMed Central

    Bhuvaneswari, T. V.; Pueppke, Steven G.; Bauer, Wolfgang D.

    1977-01-01

    Highly purified soybean lectin (SBL) was labeled with fluorescein isothiocyanate (FITC-SBL) or tritium (3H-SBL) and repurified by affinity chromatography. FITC-SBL was found to bind to living cells of 15 of the 22 Rhizobium japonicum strains tested. The lectin did not bind to cells of the other seven R. japonicum strains, or to cells of any of the nine Rhizobium strains tested which do not nodulate soybean. The binding of the lectin to the SBL-positive strains of R. japonicum was shown to be specific and reversible by hapten inhibition with d-galactose or N-acetyl-d-galactosamine. The lectin-binding properties of the SBL-positive R. japonicum strains were found to change substantially with culture age. The percentage of cells in a population exhibiting fluorescence after exposure to FITC-SBL varied between 0 and 70%. The average number of SBL molecules bound per cell varied between 0 and 2 × 106. While most strains had their highest percentage of SBL-positive cells and maximum number of SBL-binding sites per cell in the early and midlog phases of growth, one strain had a distinctly different pattern. The SBL-negative strains did not bind lectin at any stage of growth. Quantitative binding studies with 3H-SBL indicated that the affinity constant for binding of SBL to its receptor sites on R. japonicum is approximately 4 × 107m−1. Many of the binding curves were biphasic. An inhibitor of SBL binding was found to be present in R. japonicum culture filtrates. PMID:16660121

  19. Lectindb: a plant lectin database.

    PubMed

    Chandra, Nagasuma R; Kumar, Nirmal; Jeyakani, Justin; Singh, Desh Deepak; Gowda, Sharan B; Prathima, M N

    2006-10-01

    Lectins, a class of carbohydrate-binding proteins, are now widely recognized to play a range of crucial roles in many cell-cell recognition events triggering several important cellular processes. They encompass different members that are diverse in their sequences, structures, binding site architectures, quaternary structures, carbohydrate affinities, and specificities as well as their larger biological roles and potential applications. It is not surprising, therefore, that the vast amount of experimental data on lectins available in the literature is so diverse, that it becomes difficult and time consuming, if not impossible to comprehend the advances in various areas and obtain the maximum benefit. To achieve an effective use of all the data toward understanding the function and their possible applications, an organization of these seemingly independent data into a common framework is essential. An integrated knowledge base ( Lectindb, http://nscdb.bic.physics.iisc.ernet.in ) together with appropriate analytical tools has therefore been developed initially for plant lectins by collating and integrating diverse data. The database has been implemented using MySQL on a Linux platform and web-enabled using PERL-CGI and Java tools. Data for each lectin pertain to taxonomic, biochemical, domain architecture, molecular sequence, and structural details as well as carbohydrate and hence blood group specificities. Extensive links have also been provided for relevant bioinformatics resources and analytical tools. Availability of diverse data integrated into a common framework is expected to be of high value not only for basic studies in lectin biology but also for basic studies in pursuing several applications in biotechnology, immunology, and clinical practice, using these molecules.

  20. Lectins as markers for blood grouping.

    PubMed

    Khan, Fauzia; Khan, Rizwan H; Sherwani, Asma; Mohmood, Sameena; Azfer, Md A

    2002-12-01

    Lectins are unique proteins of varying biological importance. They are characterized by specific binding to carbohydrate residues, whether monosaccharides, disaccharides or polysaccharides. The sugar heads on the surface of the erythrocyte specify the different blood groups. Lectins, as an antigenic determinant of blood group, have come to be an important tool in the identification of different blood groups. A handful of lectins may be considered excellent reagents for anti-A, anti-B, anti-N etc, but the anti-A and anti-M are not yet regarded as commercially suitable antisera. Lectin from Vicia cracca has been proved to be a good anti-A, lectin from Dolichus biflorus can be used as anti-A1, and lectin from Griffonia simplicifolia as anti-B. Lectin from Vicia graminea is said to be a good typing reagent as Anti-N. On the other hand, the lectins involved in polyagglutination are absolutely essential as the reagent of choice and these cannot as yet be replaced by antibodies of any kind. Erythrocytes with exposed cryptantigens are significantly more sensitive to agglutination by certain lectins than by polyclonal antibodies. Peanut agglutinin (PNA), Polybrene, and Glycine max lectins are frequently used for the identification of different cryptantigens. The application of lectins as an anti-B reagent has proven to be as useful as human polyclonal or mouse monoclonal antibodies. Besides their specificity, lectins are excellent reagents because of their lower cost and indigenous production. The importance of various lectins used as markers for blood grouping is discussed.

  1. A novel lectin domain-containing protein (LvCTLD) associated with response of the whiteleg shrimp Penaeus (Litopenaeus) vannamei to yellow head virus (YHV).

    PubMed

    Junkunlo, Kingkamon; Prachumwat, Anuphap; Tangprasittipap, Amornrat; Senapin, Saengchan; Borwornpinyo, Suparerk; Flegel, Timothy W; Sritunyalucksana, Kallaya

    2012-07-01

    When using mRNA from gills of normal whiteleg shrimp Penaeus (Litopenaeus) vannamei as the tester and mRNA from yellow head virus (YHV)-infected shrimp as the driver, subtractive suppression hybridization (SSH) revealed that a novel EST clone of 198 bp with a putative C-type lectin-like domain (CTLD) was downregulated in YHV-infected shrimp. The clone nucleotide sequence had 99% identity with one contig MGID1052359 (1,380 bp) reported in an EST database of P. vannamei, and the presence of this target in normal shrimp was confirmed by RT-PCR using primers designed from the MGID1052359 sequence. Analysis of the primary structure of the deduced amino acid (a.a.) sequence of the contig revealed a short portion (40 a.a. residues) at its N-terminus with high similarity to a low density lipoprotein receptor (LDLR) class A domain and another 152 a.a. residues at its C-terminus with high similarity to a C-type lectin domain. Thus, the clone was named LvCTLD and three recombinant proteins (LvCTLD, the LDLR domain and the CTLD domain) were synthesized in a bacterial system based on its sequence. An in vitro encapsulation assay revealed that Sepharose 4B beads coated with rLvCTLD were encapsulated by shrimp hemocytes and that melanization followed by 24 h post-encapsulation. The encapsulation activity of rLvCTLD was inhibited by 100 mM galactose, but not mannose or EDTA. In vivo injection of rLvCTLD or rLvCTLD plus YHV resulted in a significant elevation of PO activity in the hemolymph of the challenged shrimp when compared to shrimp injected with buffer, suggesting that rLvCTLD could activate the proPO system. An ELISA test revealed that rLvCTLD could bind to YHV particles in the presence of shrimp hemolymph. Phylogenetic analysis suggested that the LvCTLD sequence was more closely related to an antiviral gene found in Penaeus monodon (PmAV) than to other reported shrimp lectins. Taken together, we conclude that a novel shrimp LvCTLD is a host recognition molecule involved in

  2. Human neutrophil migration and activation by BJcuL, a galactose binding lectin purified from Bothrops jararacussu venom

    PubMed Central

    2011-01-01

    Background Neutrophil migration to an inflamed site constitutes the first line of the innate immune response against invading microorganisms. Given the crucial role of endogenous lectins in neutrophil mobilization and activation, lectins from exogenous sources have often been considered as putative modulators of leukocyte function. Lectins purified from snake venom have been described as galactoside ligands that induce erythrocyte agglutination and platelet aggregation. This study evaluated human neutrophil migration and activation by C-type lectin BJcuL purified from Bothrops jararacussu venom. Results Utilizing fluorescence microscopy, we observed that biotinylated-BJcuL was evenly distributed on the neutrophil surface, selectively inhibited by D-galactose. Lectin was able to induce modification in the neutrophil morphology in a spherical shape for a polarized observed by optical microscopy and exposure to BJcuL in a Boyden chamber assay resulted in cell migration. After 30 minutes of incubation with BJcuL we found enhanced neutrophil functions, such as respiratory burst, zymozan phagocytosis and an increase in lissosomal volume. In addition, BJcuL delays late apoptosis neutrophils. Conclusion These results demonstrate that BJcuL can be implicated in a wide variety of immunological functions including first-line defense against pathogens, cell trafficking and induction of the innate immune response since lectin was capable of inducing potent neutrophil activation. PMID:21266049

  3. Lectin cDNA and transgenic plants derived therefrom

    SciTech Connect

    Raikhel, Natasha V.

    2000-10-03

    Transgenic plants containing cDNA encoding Gramineae lectin are described. The plants preferably contain cDNA coding for barley lectin and store the lectin in the leaves. The transgenic plants, particularly the leaves exhibit insecticidal and fungicidal properties.

  4. The response of human dendritic cells to co-ligation of pattern-recognition receptors.

    PubMed

    Dzopalic, Tanja; Rajkovic, Ivan; Dragicevic, Ana; Colic, Miodrag

    2012-04-01

    Dendritic cells (DCs) are key antigen-presenting cells that express a wide variety of pattern-recognition receptors (PRRs). Triggering of a single PRR, especially Toll-like receptors (TLRs) and C-type lectins, induces maturation of DCs, but cooperativity between multiple PRRs is needed in order to achieve an effective immune response. In this review, we summarize the published data related to the effect of individual and joint PRR agonists on DCs and Langerhans-like cells derived from monocytes (MoDCs and MoLCs, respectively). Our results demonstrate that MoDCs co-stimulated with TLR3/TLR7 and TLR3/Dectin-1 ligands induced superior T helper (Th)1 and Th17 immune responses, compared to effects of single agonists. The opposite outcome was observed after co-ligation of TLR3 and Langerin on MoLCs. These findings may be relevant to improve strategy for tumor immunotherapy.

  5. Plant as a plenteous reserve of lectin

    PubMed Central

    Hivrale, AU; Ingale, AG

    2013-01-01

    Lectins are clusters of glycoproteins of nonimmune foundation that combine specifically and reversibly to carbohydrates, mainly the sugar moiety of glycoconjugates, resulting in cell agglutination and precipitation of glycoconjugates. They are universally distributed in nature, being established in plants, fungi, viruses, bacteria, crustacea, insects, and animals, but leguminacae plants are rich source of lectins. The present review reveals the structure, biological properties, and application of plant lectins. PMID:24084524

  6. MGL Receptor and Immunity: When the Ligand Can Make the Difference

    PubMed Central

    Zizzari, Ilaria Grazia; Battisti, Federico; Rahimi, Hassan; Caponnetto, Salvatore; Pierelli, Luca; Nuti, Marianna; Rughetti, Aurelia

    2015-01-01

    C-type lectin receptors (CLRs) on antigen-presenting cells (APCs) facilitate uptake of carbohydrate antigens for antigen presentation, modulating the immune response in infection, homeostasis, autoimmunity, allergy, and cancer. In this review, we focus on the role of the macrophage galactose type C-type lectin (MGL) in the immune response against self-antigens, pathogens, and tumor associated antigens (TAA). MGL is a CLR exclusively expressed by dendritic cells (DCs) and activated macrophages (MØs), able to recognize terminal GalNAc residues, including the sialylated and nonsialylated Tn antigens. We discuss the effects on DC function induced throughout the engagement of MGL, highlighting the importance of the antigen structure in the modulation of immune response. Indeed modifying Tn-density, the length, and steric structure of the Tn-antigens can result in generating immunogens that can efficiently bind to MGL, strongly activate DCs, mimic the effects of a danger signal, and achieve an efficient presentation in HLA classes I and II compartments. PMID:26839900

  7. Lectins and their application to clinical microbiology.

    PubMed Central

    Slifkin, M; Doyle, R J

    1990-01-01

    Lectins are generally associated with plant or animal components, selectively bind carbohydrates, and interact with procaryotic and eucaryotic cells. Lectins have various specificities that are associated with their ability to interact with acetylaminocarbohydrates, aminocarbohydrates, sialic acids, hexoses, pentoses, and as other carbohydrates. Microbial surfaces generally contain many of the sugar residues that react with lectins. Lectins are presently used in the clinical laboratory to type blood cells and are used in a wide spectrum of applications, including, in part, as carriers of chemotherapeutic agents, as mitogens, for fractionation of animal cells, and for investigations of cellular surfaces. Numerous studies have shown that lectins can be used to identify rapidly certain microorganisms isolated from a clinical specimen or directly in a clinical specimen. Lectins have been demonstrated to be important diagnostic reagents in the major realms of clinical microbiology. Thus, they have been applied in bacteriology, mycology, mycobacteriology, and virology for the identification and/or differentiation of various microorganisms. Lectins have been used successfully as epidemiologic as well as taxonomic markers of specific microorganisms. Lectins provide the clinical microbiologist with cost-effective and potential diagnostic reagents. This review describes the applications of lectins in clinical microbiology. Images PMID:2200603

  8. Isolation, cloning, and characterization of a novel phosphomannan-binding lectin from porcine serum.

    PubMed

    Ma, Bruce Yong; Nakamura, Natsuko; Dlabac, Vladimir; Naito, Haruna; Yamaguchi, Shinsuke; Ishikawa, Makiko; Nonaka, Motohiro; Ishiguro, Masaji; Kawasaki, Nobuko; Oka, Shogo; Kawasaki, Toshisuke

    2007-04-27

    Mannan-binding protein (MBP) is a C-type serum lectin that is an important constituent of the innate immune defense because it activates the complement system via the lectin pathway. While the pig has been proposed to be an attractive source of xenotransplantable tissues and organs, little is known about porcine MBP. In our previous studies, phosphomannan, but not mannan, was found to be an effective inhibitor of the C1q-independent bactericidal activity of newborn piglet serum against some rough strains of Gram-negative bacteria. In contrast, the inhibitory activities of phosphomannan and mannan were very similar in the case of MBP-dependent bactericidal activity against rough strains of Escherichia coli K-12 and S-16. Based on these findings, we inferred that an MBP-like lectin with slightly or completely different carbohydrate binding specificity might exist in newborn piglet serum and be responsible for the C1q-independent bactericidal activity. Herein we report that a novel phosphomannan-binding lectin (PMBL) of 33 kDa under reducing conditions was isolated from both newborn and adult porcine serum and characterized. Porcine PMBL functionally activated the complement system via the lectin pathway triggered by binding with both phosphomannan (P-mannan) and mannan, which, unlike MBP, was effectively inhibited by mannose 6-phosphate- or galatose-containing oligosaccharides. Our observations suggest that porcine PMBL plays a critical role in the innate immune defense from the newborn stage to adult-hood, and the establishment of a newborn piglet experimental model for the innate immune system studies is a valuable step toward elucidation of the physiological function and molecular mechanism of lectin pathway. PMID:17324926

  9. Mosaic lectin labelling in the quail collecting ducts.

    PubMed

    Menghi, G; Gabrielli, M G; Accili, D

    1995-04-01

    Morphological and histoenzymological differences have been observed between intercalated and principal cells of the quail Coturnix coturnix japonica collecting ducts. The present study was designed to shed light on the lectin affinity of the collecting duct cells within cortex and medulla by the use of HRP-labelled lectins combined with glycosidase degradation. Binding of PNA and RCA-I lectins consequent to enzymatic release of sialic acid revealed abundant sialylated carbohydrate moieties within the principal cell cytoplasm. This characteristic binding pattern differed considerably from the staining observed in the intercalated cells. Interesting information also emerged about the presence of sialoglycoconjugates having the terminal disaccharide sialic acid-beta-N-acetylgalactosamine originating from the increased SBA binding and the unmodified DBA labelling after removal of sialic acid. Sequential degradation by sialidase/beta-galactosidase followed by incubation with DBA offered the possibility to suspect that the receptor sugar for the penultimate beta-galactose may be N-acetylgalactosamine. Conversely, we were not able to define the accept sugar for penultimate beta-GalNAc owing to the lack of availability of beta-N-acetylgalactosaminidase enzyme. When although further studies are clearly needed to elucidate the physiological role of the cellular sialoglycoconjugates detected, the present results already provide valuable insight into the carbohydrate composition of intercalated and principal cells in the quail collecting ducts.

  10. Lectin engineering, a molecular evolutionary approach to expanding the lectin utilities.

    PubMed

    Hu, Dan; Tateno, Hiroaki; Hirabayashi, Jun

    2015-01-01

    In the post genomic era, glycomics--the systematic study of all glycan structures of a given cell or organism--has emerged as an indispensable technology in various fields of biology and medicine. Lectins are regarded as "decipherers of glycans", being useful reagents for their structural analysis, and have been widely used in glycomic studies. However, the inconsistent activity and availability associated with the plant-derived lectins that comprise most of the commercially available lectins, and the limit in the range of glycan structures covered, have necessitated the development of innovative tools via engineering of lectins on existing scaffolds. This review will summarize the current state of the art of lectin engineering and highlight recent technological advances in this field. The key issues associated with the strategy of lectin engineering including selection of template lectin, construction of a mutagenesis library, and high-throughput screening methods are discussed.

  11. Identification of natural killer cell receptor genes in the genome of the marsupial Tasmanian devil (Sarcophilus harrisii).

    PubMed

    van der Kraan, Lauren E; Wong, Emily S W; Lo, Nathan; Ujvari, Beata; Belov, Katherine

    2013-01-01

    Within the mammalian immune system, natural killer (NK) cells contribute to the first line of defence against infectious agents and tumours. Their activity is regulated, in part, by cell surface NK cell receptors. NK receptors can be divided into two unrelated, but functionally analogous superfamilies based on the structure of their extracellular ligand-binding domains. Receptors belonging to the C-type lectin superfamily are predominantly encoded in the natural killer complex (NKC), while receptors belonging to the immunoglobulin superfamily are predominantly encoded in the leukocyte receptor complex (LRC). Natural killer cell receptors are emerging as a rapidly evolving gene family which can display significant intra- and interspecific variation. To date, most studies have focused on eutherian mammals, with significantly less known about the evolution of these receptors in marsupials. Here, we describe the identification of 43 immunoglobulin domain-containing LRC genes in the genome of the Tasmanian devil (Sarcophilus harrisii), the largest remaining marsupial carnivore and only the second marsupial species to be studied. We also identify orthologs of NKC genes KLRK1, CD69, CLEC4E, CLEC1B, CLEC1A and an ortholog of an opossum NKC receptor. Characterisation of these regions in a second, distantly related marsupial provides new insights into the dynamic evolutionary histories of these receptors in mammals. Understanding the functional role of these genes is also important for the development of therapeutic agents against Devil Facial Tumour Disease, a contagious cancer that threatens the Tasmanian devil with extinction.

  12. Lectin-based Isolation and Culture of Mouse Embryonic Motoneurons

    PubMed Central

    Conrad, Rebecca; Jablonka, Sibylle; Sczepan, Teresa; Sendtner, Michael; Wiese, Stefan; Klausmeyer, Alice

    2011-01-01

    Spinal motoneurons develop towards postmitotic stages through early embryonic nervous system development and subsequently grow out dendrites and axons. Neuroepithelial cells of the neural tube that express Nkx6.1 are the unique precursor cells for spinal motoneurons1. Though postmitotic motoneurons move towards their final position and organize themselves into columns along the spinal tract2,3. More than 90% of all these differentiated and positioned motoneurons express the transcription factors Islet 1/2. They innervate the muscles of the limbs as well as those of the body and the inner organs. Among others, motoneurons typically express the high affinity receptors for brain derived neurotrophic factor (BDNF) and Neurotrophin-3 (NT-3), the tropomyosin-related kinase B and C (TrkB, TrkC). They do not express the tropomyosin-related kinase A (TrkA)4. Beside the two high affinity receptors, motoneurons do express the low affinity neurotrophin receptor p75NTR. The p75NTR can bind all neurotrophins with similar but lower affinity to all neurotrophins than the high affinity receptors would bind the mature neurotrophins. Within the embryonic spinal cord, the p75NTR is exclusively expressed by the spinal motoneurons5. This has been used to develop motoneuron isolation techniques to purify the cells from the vast majority of surrounding cells6. Isolating motoneurons with the help of specific antibodies (panning) against the extracellular domains of p75NTR has turned out to be an expensive method as the amount of antibody used for a single experiment is high due to the size of the plate used for panning. A much more economical alternative is the use of lectin. Lectin has been shown to specifically bind to p75NTR as well7. The following method describes an alternative technique using wheat germ agglutinin for a preplating procedure instead of the p75NTR antibody. The lectin is an extremely inexpensive alternative to the p75NTR antibody and the purification grades using

  13. Fishing for lectins from diverse sequence libraries by yeast surface display - an exploratory study.

    PubMed

    Ryckaert, Stefan; Callewaert, Nico; Jacobs, Pieter P; Dewaele, Sylviane; Dewerte, Isabelle; Contreras, Roland

    2008-02-01

    The establishment of a robust technology platform for the expression cloning of carbohydrate-binding proteins remains a key challenge in glycomics. Here we explore the utility of using yeast surface display (YSD) technology in the interaction-based lectin cloning from complete cDNA libraries. This should pave the way for more detailed studies of protein-carbohydrate interactions. To evaluate the performance of this system, lectins representing three different subfamilies (galectins, siglecs, and C-type lectins) were successfully displayed on the surface of Saccharomyces cerevisiae and Pichia pastoris as a-agglutinin and/or alpha-agglutinin fusions. The predicted carbohydrate-binding activity could be detected for three out of five lectins tested (galectin-1, galectin-3, and siaoadhesin). For galectin-4 and E-selectin, no specific carbohydrate-binding activity could be detected. We also demonstrate that proteins with carbohydrate affinity can be specifically isolated from complex metazoan cDNA libraries through multiple rounds of FACS sorting, employing multivalent, fluorescent-labeled polyacrylamide-based glycoconjugates.

  14. Fishing for lectins from diverse sequence libraries by yeast surface display - an exploratory study.

    PubMed

    Ryckaert, Stefan; Callewaert, Nico; Jacobs, Pieter P; Dewaele, Sylviane; Dewerte, Isabelle; Contreras, Roland

    2008-02-01

    The establishment of a robust technology platform for the expression cloning of carbohydrate-binding proteins remains a key challenge in glycomics. Here we explore the utility of using yeast surface display (YSD) technology in the interaction-based lectin cloning from complete cDNA libraries. This should pave the way for more detailed studies of protein-carbohydrate interactions. To evaluate the performance of this system, lectins representing three different subfamilies (galectins, siglecs, and C-type lectins) were successfully displayed on the surface of Saccharomyces cerevisiae and Pichia pastoris as a-agglutinin and/or alpha-agglutinin fusions. The predicted carbohydrate-binding activity could be detected for three out of five lectins tested (galectin-1, galectin-3, and siaoadhesin). For galectin-4 and E-selectin, no specific carbohydrate-binding activity could be detected. We also demonstrate that proteins with carbohydrate affinity can be specifically isolated from complex metazoan cDNA libraries through multiple rounds of FACS sorting, employing multivalent, fluorescent-labeled polyacrylamide-based glycoconjugates. PMID:18086821

  15. [C-TYPE NATRIURETIC PEP- TIDE: WHAT, WHERE AND WHAT FOR IS THIS?].

    PubMed

    Korostyshevskaya, I M; Maksimov, V F; Rudenko, N S

    2015-05-01

    The up-to-day world-wide data about the structure, distribution, and physiological effects of the most poorly known among the natriuretic peptides--the C-type (CNP)--are summarized in the review. Despite its name, this peptide does not stimulate sodium excretion but shares the prominent vasodilating and antyproliferating effects in different organs and tissues. The special emphasis is attended to CNP functions in central nervous system. The information about the peptide molecular biology, including intracellular processing, blood peptide concentration, specific receptors structure, and signaling pathways in target cells is presented.

  16. Differential binding properties of Gal/GalNAc specific lectins available for characterization of glycoreceptors.

    PubMed

    Wu, A M; Song, S C; Sugii, S; Herp, A

    1997-01-01

    Differentiating the binding properties of applied lectins should facilitate the selection of lectins for characterization of glycoreceptors on the cell surface. Based on the binding specificities studied by inhibition assays of lectin-glycan interactions, over twenty Gal and/or GalNAc specific lectins have been divided into eight groups according to their specificity for structural units (lectin determinants), which are the disaccharide as all or part of the determinants and of GalNAc alpha 1-->Ser (Thr) of the peptide chain. A scheme of codes for lectin determinants is illustrated as follows: (1) F (GalNAc alpha 1-->3GalNAc), Forssman specific disaccharide--Dolichos biflorus (DBL), Helix pomatia (HPL) and Wistaria floribunda (WFL) lectins. (2) A (GalNAc alpha 1-->3 Gal), blood group A specific disaccharide--Codium fragile subspecies tomentosoides (CFT), Soy bean (SBL), Vicia villosa-A4 (VVL-A4), and Wistaria floribunda (WFL) lectins. (3) Tn (GalNAc alpha 1-->Ser (Thr) of the protein core)--Vicia villosa B4 (VVL-B4), Salvia sclarea (SSL), Maclura pomifera (MPL), Bauhinia purpurea alba (BPL) and Artocarpus integrifolia (Jacalin, AIL). (4) T (Gal beta 1-->3GalNAc), the mucin type sugar sequences on the human erythrocyte membrane(T alpha), T antigen or the disaccharides at the terminal nonreducing end of gangliosides (T beta)--Peanut (PNA), Bauhinia purpurea alba (BPL), Maclura pomifera (MPL), Sophora japonica (SJL), Artocarpus lakoocha (Artocarpin) lectins and Abrus precatorius agglutinin (APA).(5) I and II (Gal beta 1-->3(4)GlcNAc)--the disaccharide residue at the nonreducing end of the carbohydrate chains derived from either N- or O-glycosidic linkage--Ricinus communis agglutinin (RCA1), Datura stramonium (TAL, Thorn apple), Erythrina cristagalli (ECL, Coral tree), and Geodia cydonium (GCL). (6) B (Gal alpha 1-->3Gal), human blood group B specific disaccharide--Griffonia(Banderiaea) simplicifolia B4 (GSI-B4). (7) E (Gal alpha 1-->4Gal), receptors for pathogenic E

  17. Impact of the PI3-kinase/Akt pathway on ITAM and hemITAM receptors: haemostasis, platelet activation and antithrombotic therapy.

    PubMed

    Moroi, Alyssa J; Watson, Steve P

    2015-04-01

    Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that are activated in response to various stimulants, and they regulate many processes including inflammation; the stress response; gene transcription; and cell proliferation, differentiation, and death. Increasing reports have shown that the PI3Ks and their downstream effector Akt are activated by several platelet receptors that regulate platelet activation and haemostasis. Platelets express two immunoreceptor tyrosine based activation motif (ITAM) receptors, collagen receptor glycoprotein VI (GPVI) and Fcγ receptor IIA (FcγRIIA), which are characterized by two YxxL sequences separated by 6-12 amino acids. Activation of an ITAM receptor initiates a reaction cascade via its YxxL sequence in which signaling molecules such as spleen tyrosine kinase (Syk), linker for activation of T cells (LAT) and phospholipase C γ2 (PLCγ2) become activated, leading to platelet activation. Platelets also express another receptor, C-type lectin 2 (CLEC-2), which has a single YxxL sequence, so it is appropriately called a hemITAM receptor. ITAM receptors and the hemITAM receptor share many signaling features. Here we will summarize our current knowledge about how the PI3K/Akt pathway regulates (hem)ITAM receptor-mediated platelet activation and haemostasis and discuss the possible benefits of targeting PI3K/Akt as an antithrombotic therapy.

  18. Lectin binding studies on a glycopolymer brush flow-through biosensor by localized surface plasmon resonance.

    PubMed

    Rosencrantz, Ruben R; Nguyen, Vu Hoa; Park, Hyunji; Schulte, Christine; Böker, Alexander; Schnakenberg, Uwe; Elling, Lothar

    2016-08-01

    A localized surface plasmon resonance biosensor in a flow-through configuration was applied for investigating kinetics of lectin binding to surface-grafted glycopolymer brushes. Polycarbonate filter membranes with pore sizes of 400 nm were coated with a 114-nm thick gold layer and used as substrate for surface-initiated atom-transfer radical polymerization of a glycomonomer. These grafted from glycopolymer brushes were further modified with two subsequent enzymatic reactions on the surface to yield an immobilized trisaccharide presenting brush. Specific binding of lectins including Clostridium difficile toxin A receptor domain to the glycopolymer brush surface could be investigated in a microfluidic setup with flow-through of the analytes and transmission surface plasmon resonance spectroscopy. Graphical abstract Glycopolymer brushes serve as high affinity ligands for lectin and toxin interactions in a sensitive, disposable flow-through LSPR biosensor. PMID:27277814

  19. An Overview of Pathogen Recognition Receptors for Innate Immunity in Dental Pulp

    PubMed Central

    Jang, Ji-Hyun; Shin, Hee Woong; Lee, Jung Min; Lee, Hyeon-Woo; Kim, Eun-Cheol; Park, Sang Hyuk

    2015-01-01

    Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution. Currently identified PRR families are the Toll-like receptors (TLRs), the C-type lectin receptors (CLRs), the nucleotide-binding oligomerization domain-like receptors (NLRs), the retinoic acid-inducible gene-I-like receptors (RLRs), and the AIM2-like receptor (ALR). The environment of the dental pulp is substantially different from that of other tissues of the body. Dental pulp resides in a low compliance root canal system that limits the expansion of pulpal tissues during inflammatory processes. An understanding of the PRRs in dental pulp is important for immunomodulation and hence for developing therapeutic targets in the field of endodontics. Here we comprehensively review recent finding on the PRRs and the mechanisms by which innate immunity is activated. We focus on the PRRs expressed on dental pulp and periapical tissues and their role in dental pulp inflammation. PMID:26576076

  20. An Overview of Pathogen Recognition Receptors for Innate Immunity in Dental Pulp.

    PubMed

    Jang, Ji-Hyun; Shin, Hee Woong; Lee, Jung Min; Lee, Hyeon-Woo; Kim, Eun-Cheol; Park, Sang Hyuk

    2015-01-01

    Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution. Currently identified PRR families are the Toll-like receptors (TLRs), the C-type lectin receptors (CLRs), the nucleotide-binding oligomerization domain-like receptors (NLRs), the retinoic acid-inducible gene-I-like receptors (RLRs), and the AIM2-like receptor (ALR). The environment of the dental pulp is substantially different from that of other tissues of the body. Dental pulp resides in a low compliance root canal system that limits the expansion of pulpal tissues during inflammatory processes. An understanding of the PRRs in dental pulp is important for immunomodulation and hence for developing therapeutic targets in the field of endodontics. Here we comprehensively review recent finding on the PRRs and the mechanisms by which innate immunity is activated. We focus on the PRRs expressed on dental pulp and periapical tissues and their role in dental pulp inflammation.

  1. Rheologic characterization of vegetal lectins by dissociation of induced erythrocyte agglutinates.

    PubMed

    Rasia, R J; Valverde, J R; Gentils, M; Cauchois, C; Stoltz, J F

    1997-01-01

    Energy evolved from hemagglutination reaction or spent in dissociating erythrocyte agglutinates has been proved to be an excellent parameter for analyzing cell-cell interactions mediated by bridging molecules such as antibodies or lectins. We developed a new rheo-optical method to estimate the energy of dissociation of red blood cell agglutinates. In a Couette shear field agglutinates can be dissociated until a suspension of monodispersed cells is obtained. Intensity of light backscattered by suspended agglutinates increases during their mechanical dissociation. Variation of backscattered light intensity correlates with the energy spent in the process. The adhesive energy of erythrocyte agglutination induced by lectins has been estimated by applying this method. Two specific lectins (Dolichus Biflorus agglutinin and Ulex Europaeus agglutinin) and a new lectin obtained from Amarantus Cruentus seeds which specificity is unknown were studied. Results obtained in this work for Dolichus Biflorus lectin are comparable with values published by other authors. An asymptotic decrease of adhesive energy was observed when the mechanical dissociation was applied several times on the same sample. Our results suggest that the cell detachment is accompanied by the extraction of membrane receptors. This finding is consistent with results obtained by other authors.

  2. Mincle, an Innate Immune Receptor, Is Expressed in Urothelial Cancer Cells of Papillomavirus-Associated Urothelial Tumors of Cattle

    PubMed Central

    Roperto, Sante; Russo, Valeria; Esposito, Iolanda; Ceccarelli, Dora Maria; Paciello, Orlando; Avallone, Luigi; Capparelli, Rosanna; Roperto, Franco

    2015-01-01

    Background Mincle, macrophage-inducible C-type lectin, is a member of C-type lectin receptors. It plays an important role in anti-mycobacterial and anti-fungal immunity. Furthermore it senses dead cells through its primary ligand SAP130. Materials and Findings We examined ten urothelial tumors of the urinary bladder of cattle. Eight of them expressed E5 cDNA of bovine papillomaviruses type 2 (BPV-2) and type 13 (BPV-13) that belong to Deltapapillomavirus genus. Two of them were not examined for detection of E5 cDNA. Mincle expression appeared to occur in urothelial neoplastic cells only. No mincle expression was detected in urothelial cells from healthy cattle. Mincle expression was characterized by a membranous pattern in papillary urothelial cancers; isolated and/or clustered urothelial cells showing a strong cytoplasmic immunoreactivity were primarily seen in invasive urothelial cancers. Conclusion This is the first study about the expression of mincle in veterinary oncology and the first report which describes the expression of functional mincle receptor in neoplastic cells in medical literature. As it has been shown that urothelial cancer cells have the ability to function as antigen-presenting cells (APCs), it is conceivable that mincle expression is involved in the presentation of cancer cell antigens to cells of the immune system. Furthermore, since expression of mincle contributes to the control of Mycobacterium bovis BCG infection, this study has exciting clinical implications in comparative medicine keeping in mind that Bacillus Calmette-Guérin (BCG) immunotherapy is currently the most effective treatment of non-muscle invasive bladder cancer in man. Mincle expression in urothelial tumor cells warrants further study to better understand the role, if any, of this receptor in bladder cancer. Future studies will provide insights in the role of mincle receptor of urothelial cancer cells in antitumor immunotherapy. PMID:26513724

  3. [Antagonistic effect of gingerols against TNF-α release, ROS overproduction and RIP3 expression increase induced by lectin from Pinellia ternata].

    PubMed

    Yu, Hong-li; Mao, Shan-hu; Zhao, Teng-fei; Wu, Hao; Pan, Yao-zong; Shu, Chen-yan

    2015-09-01

    To explore the antagonistic effect of gingerols against the inflammation induced by lectin from Pinellia ternata. In this study, ELISA method was used to determine the effect of different extracts from gingerols on the release of inflammatory factor TNF-α from macrophages induced by lectin from P. ternata. The fluorescence probe was used to determine the effect of gingerols on the changes in ROS of macrophages induced by lectin from P. ternata. The western-blot method was applied to study the effect of gingerols on the increase in expression of cell receptor interacting protein RIP3 in macrophages induced by lectin from P. ternata. The scanning electron microscope (SEM) was used to study the effect of gingerols on morphological changes in macrophages induced by lectin from P. ternata. According to the results, gingerols can significantly inhibit the release of inflammatory factor from macrophages induced by lectin from P. ternata, ROS overproduction and increase in RIP3 expression. SEM results showed that gingerols can inhibit the cytomorphosis and necrocytosis induced by lectin from P. ternata. Fresh ginger's detoxication may be related to gingerols' effects in inhibiing release of inflammatory factor, ROS overproduction and increase in RIP3 expression caused by macrophages induced by lectin from P. ternata, which are mainly inflammatory development. PMID:26983212

  4. Structural and functional properties of C-type starches.

    PubMed

    Cai, Jinwen; Cai, Canhui; Man, Jianmin; Zhou, Weidong; Wei, Cunxu

    2014-01-30

    This study investigated the structural and functional properties of C-type starches from pea seeds, faba bean seeds, yam rhizomes and water chestnut corms. These starches were mostly oval in shape with significantly different sizes and contents of amylose, damaged starch and phosphorus. Pea, faba bean and water chestnut starches had central hila, and yam starch had eccentric hilum. Water chestnut and yam starches had higher amylopectin short and long chain, respectively. Water chestnut and faba bean starches showed CA-type crystallinities, and pea and yam starches had C-type crystallinities. Water chestnut starch had the highest swelling power, granule swelling and pasting viscosity, lowest gelatinization temperatures and enthalpy. Faba bean starch had the lowest pasting viscosity, whereas yam starch had the highest gelatinization temperatures. Water chestnut and yam starches possessed significantly higher and lower susceptibility to acid and enzyme hydrolysis, the highest and lowest RDS contents, and the lowest and highest RS contents, respectively.

  5. Platform Synthetic Lectins for Divalent Carbohydrate Recognition in Water

    PubMed Central

    Carter, Tom S.; Mooibroek, Tiddo J.; Stewart, Patrick F. N.; Crump, Matthew P.; Galan, M. Carmen

    2016-01-01

    Abstract Biomimetic carbohydrate receptors (“synthetic lectins”) have potential as agents for biological research and medicine. However, although effective strategies are available for “all‐equatorial” carbohydrates (glucose, etc.), the recognition of other types of saccharide under natural (aqueous) conditions is less well developed. Herein we report a new approach based on a pyrene platform with polar arches extending from aryl substituents. The receptors are compatible with axially substituted carbohydrates, and also feature two identical binding sites, thus mimicking the multivalency observed for natural lectins. A variant with negative charges forms 1:2 host/guest complexes with aminosugars, with K 1>3000 m −1 for axially substituted mannosamine, whereas a positively charged version binds the important α‐sialyl unit with K 1≈1300 m −1. PMID:27312071

  6. Galactose-specific seed lectins from Cucurbitaceae.

    PubMed

    Swamy, Musti J; Marapakala, Kavitha; Sultan, Nabil Ali M; Kenoth, Roopa

    2015-01-01

    Lectins, the carbohydrate binding proteins have been studied extensively in view of their ubiquitous nature and wide-ranging applications. As they were originally found in plant seed extracts, much of the work on them was focused on plant seed lectins, especially those from legume seeds whereas much less attention was paid to the lectins from other plant families. During the last two decades many studies have been reported on lectins from the seeds of Cucurbitaceae species. The main focus of the present review is to provide an overview of the current knowledge on these proteins, especially with regard to their physico-chemical characterization, interaction with carbohydrates and hydrophobic ligands, 3-dimensional structure and similarity to type-II ribosome inactivating proteins. The future outlook of research on these galactose-specific proteins is also briefly considered.

  7. CancerLectinDB: a database of lectins relevant to cancer.

    PubMed

    Damodaran, Deepa; Jeyakani, Justin; Chauhan, Alok; Kumar, Nirmal; Chandra, Nagasuma R; Surolia, Avadhesha

    2008-04-01

    The role of lectins in mediating cancer metastasis, apoptosis as well as various other signaling events has been well established in the past few years. Data on various aspects of the role of lectins in cancer is being accumulated at a rapid pace. The data on lectins available in the literature is so diverse, that it becomes difficult and time-consuming, if not impossible to comprehend the advances in various areas and obtain the maximum benefit. Not only do the lectins vary significantly in their individual functional roles, but they are also diverse in their sequences, structures, binding site architectures, quaternary structures, carbohydrate affinities and specificities as well as their potential applications. An organization of these seemingly independent data into a common framework is essential in order to achieve effective use of all the data towards understanding the roles of different lectins in different aspects of cancer and any resulting applications. An integrated knowledge base (CancerLectinDB) together with appropriate analytical tools has therefore been developed for lectins relevant for any aspect of cancer, by collating and integrating diverse data. This database is unique in terms of providing sequence, structural, and functional annotations for lectins from all known sources in cancer and is expected to be a useful addition to the number of glycan related resources now available to the community. The database has been implemented using MySQL on a Linux platform and web-enabled using Perl-CGI and Java tools. Data for individual lectins pertain to taxonomic, biochemical, domain architecture, molecular sequence and structural details as well as carbohydrate specificities. Extensive links have also been provided for relevant bioinformatics resources and analytical tools. Availability of diverse data integrated into a common framework is expected to be of high value for various studies on lectin cancer biology. CancerLectinDB can be accessed through

  8. Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa

    PubMed Central

    Osthoff, Michael; Brown, Karl D.; Kong, David C.M.; Daniell, Mark

    2014-01-01

    Purpose Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. Methods Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT–PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. Results MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. Conclusions MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed. PMID:24426774

  9. Epidemiological characterization of Neisseria gonorrhoeae by lectins.

    PubMed Central

    Schalla, W O; Whittington, W L; Rice, R J; Larsen, S A

    1985-01-01

    A total of 101 isolates of penicillinase-producing and non-penicillinase-producing Neisseria gonorrhoeae with known nutritional requirements, plasmid content, and serovars, were examined for lectin agglutination patterns. These isolates were from outbreaks in Georgia, California, Hawaii, and Pennsylvania. Cell suspensions made from 16- to 18-h cultures were mixed with 14 different lectins, and the resultant agglutination patterns were classified as agglutination groups. Among the 101 isolates tested, 24 different agglutination groups were demonstrated. Of the organisms tested, 55% were located in 3 of the 24 groups, and 86% of the isolates reacted with the lectins Trichosanthes kinlowii, Griffonia simplicifolia I, peanut agglutinin, soybean agglutinin, potato agglutinin, and wheat germ agglutinin. One isolate did not react with peanut or potato agglutinin, five isolates lacked reactivity with potato agglutinin, and six isolates did not react with wheat germ agglutinin. Of the wheat germ-negative isolates, four were from Pennsylvania and were identical with regard to auxotype, plasmid content, serovar, and lectin group. The other two wheat germ-negative isolates were from California and were unrelated by the same criteria to the four Pennsylvania isolates and to each other. Among the isolates tested, there were no differences in lectin groups with regard to the sex of the patient. In the Georgia collection, agglutination with one lectin group was confined to isolates of serogroup IA. This association was not observed for the other geographic areas. Some isolates showing identical auxotype, plasmid content, and serovars could be differentiated based on lectin agglutination patterns, whereas other isolates were identical by all testing criteria. PMID:3930560

  10. Toll-like receptors: the swiss army knife of immunity and vaccine development

    PubMed Central

    Dowling, Jennifer K; Mansell, Ashley

    2016-01-01

    Innate immune cells have a critical role in defense against infection and disease. Central to this is the broad specificity with which they can detect pathogen-associated patterns and danger-associated patterns via the pattern recognition receptors (PRRs) they express. Several families of PRRs have been identified including: Toll-like receptors (TLRs), C-type lectin-like receptors, retinoic acid-inducible gene-like receptors and nucleotide-binding oligomerization domain–like receptors. TLRs are one of the most largely studied families of PRRs. The binding of ligands to TLRs on antigen presenting cells (APCs), mainly dendritic cells, leads to APC maturation, induction of inflammatory cytokines and the priming of naive T cells to drive acquired immunity. Therefore, activation of TLRs promotes both innate inflammatory responses and the induction of adaptive immunity. Consequently, in the last two decades mounting evidence has inextricably linked TLR activation with the pathogenesis of immune diseases and cancer. It has become advantageous to harness these aspects of TLR signaling therapeutically to accelerate and enhance the induction of vaccine-specific responses and also target TLRs with the use of biologics and small molecule inhibitors for the treatment of disease. In these respects, TLRs may be considered a ‘Swiss Army' knife of the immune system, ready to respond in a multitude of infectious and disease states. Here we describe the latest advances in TLR-targeted therapeutics and the use of TLR ligands as vaccine adjuvants. PMID:27350884

  11. Structure of FcRY, an avian immunoglobulin receptor related to mammalian mannose receptors, and its complex with IgY.

    PubMed

    He, Yongning; Bjorkman, Pamela J

    2011-07-26

    Fc receptors transport maternal antibodies across epithelial cell barriers to passively immunize newborns. FcRY, the functional counterpart of mammalian FcRn (a major histocompatibility complex homolog), transfers IgY across the avian yolk sac, and represents a new class of Fc receptor related to the mammalian mannose receptor family. FcRY and FcRn bind immunoglobulins at pH ≤6.5, but not pH ≥7, allowing receptor-ligand association inside intracellular vesicles and release at the pH of blood. We obtained structures of monomeric and dimeric FcRY and an FcRY-IgY complex and explored FcRY's pH-dependent binding mechanism using electron cryomicroscopy (cryoEM) and small-angle X-ray scattering. The cryoEM structure of FcRY at pH 6 revealed a compact double-ring "head," in which the N-terminal cysteine-rich and fibronectin II domains were folded back to contact C-type lectin-like domains 1-6, and a "tail" comprising C-type lectin-like domains 7-8. Conformational changes at pH 8 created a more elongated structure that cannot bind IgY. CryoEM reconstruction of FcRY dimers at pH 6 and small-angle X-ray scattering analysis at both pH values confirmed both structures. The cryoEM structure of the FcRY-IgY revealed symmetric binding of two FcRY heads to the dimeric FcY, each head contacting the C(H)4 domain of one FcY chain. FcRY shares structural properties with mannose receptor family members, including a head and tail domain organization, multimerization that may regulate ligand binding, and pH-dependent conformational changes. Our results facilitate understanding of immune recognition by the structurally related mannose receptor family and comparison of diverse methods of Ig transport across evolution.

  12. Mannose-binding dietary lectins induce adipogenic differentiation of the marrow-derived mesenchymal cells via an active insulin-like signaling mechanism.

    PubMed

    Bajaj, Manmohan; Hinge, Ashwini; Limaye, Lalita S; Gupta, Rajesh Kumar; Surolia, Avadhesha; Kale, Vaijayanti P

    2011-04-01

    We have recently demonstrated that the mannose-binding lectins, namely banana lectin (BL) and garlic lectin (GL), interacted with the insulin receptors on M210B4 cells--an established mesenchymal cell line of murine marrow origin--and initiate mitogen-activated protein kinase kinase (MEK)-dependent extracellular signal-regulated kinase (ERK) signaling in them. In this study, we show that this lectin-mediated active ERK signaling culminates into an adipogenic differentiation of these cells. Gene expression studies indicate that the effect takes place at the transcriptional level. Experiments carried out with pharmacological inhibitors show that MEK-dependent ERK and phosphatidylinositol 3-kinase-dependent AKT pathways are positive regulators of the lectin- and insulin-mediated adipogenic differentiation, while stress-activated kinase/c-jun N-terminal kinase pathway acts as a negative one. Since both lectins could efficiently substitute for insulin in the standard adipogenic induction medium, they may perhaps serve as molecular tools to study the mechanistic aspects of the adipogenic process that are independent of cell proliferation. Our study clearly demonstrates the ability of BL and GL to activate insulin-like signaling in the mesenchymal cells in vitro leading to their adipocytic differentiation. The dietary origin of these lectins underscores an urgent need to examine their in vivo effects on tissue homeostasis.

  13. Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential.

    PubMed

    Gardères, Johan; Bourguet-Kondracki, Marie-Lise; Hamer, Bojan; Batel, Renato; Schröder, Heinz C; Müller, Werner E G

    2015-08-07

    An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest.

  14. Redox processes controlling the biogenesis of c-type cytochromes.

    PubMed

    Bonnard, Géraldine; Corvest, Vincent; Meyer, Etienne H; Hamel, Patrice P

    2010-11-01

    In mitochondria, two mono heme c-type cytochromes are essential electron shuttles of the respiratory chain. They are characterized by the covalent attachment of their heme C to a CXXCH motif in the apoproteins. This post-translational modification occurs in the intermembrane space compartment. Dedicated assembly pathways have evolved to achieve this chemical reaction that requires a strict reducing environment. In mitochondria, two unrelated machineries operate, the rather simple System III in yeast and animals and System I in plants and some protozoans. System I is also found in bacteria and shares some common features with System II that operates in bacteria and plastids. This review aims at presenting how different systems control the chemical requirements for the heme ligation in the compartments where cytochrome c maturation takes place. A special emphasis will be given on the redox processes that are required for the heme attachment reaction onto apocytochromes c.

  15. P2C-Type ATPases and Their Regulation.

    PubMed

    Retamales-Ortega, Rocío; Vio, Carlos P; Inestrosa, Nibaldo C

    2016-03-01

    P2C-type ATPases are a subfamily of P-type ATPases comprising Na(+)/K(+)-ATPase and H(+)/K(+)-ATPase. Na(+)/K(+)-ATPase is ubiquitously expressed and has been implicated in several neurological diseases, whereas H(+)/K(+)-ATPase is found principally in the colon, stomach, and kidney. Both ATPases have two subunits, α and β, but Na(+)/K(+)-ATPase also has a regulatory subunit called FXYD, which has an important role in cancer. The most important functions of these ATPases are homeostasis, potassium regulation, and maintaining a gradient in different cell types, like epithelial cells. Na(+)/K(+)-ATPase has become a center of attention ever since it was proposed that it might play a crucial role in neurological disorders such as bipolar disorder, mania, depression, familial hemiplegic migraine, rapid-onset dystonia parkinsonism, chronic stress, epileptogenesis, and Alzheimer's disease. On the other hand, it has been reported that lithium could have a neuroprotective effect against ouabain, which is the best known Na(+)/K(+)-ATPase inhibitor, but and high concentrations of lithium could affect negatively H(+)/K(+)-ATPase activity, that has a key role in regulating acidosis and potassium deficiencies. Finally, potassium homeostasis regulation is composed of two main mechanisms, extrarenal and renal. Extrarenal mechanism controls plasma levels, shifting potassium from the extracellular to the intracellular, whereas renal mechanism concerns with body balance and is influenced by potassium intake and its urinary excretion. In this article, we discuss the functions, isoforms, and localization of P2C-type ATPases, describe some of their modulators, and discuss their implications in some diseases.

  16. P2C-Type ATPases and Their Regulation.

    PubMed

    Retamales-Ortega, Rocío; Vio, Carlos P; Inestrosa, Nibaldo C

    2016-03-01

    P2C-type ATPases are a subfamily of P-type ATPases comprising Na(+)/K(+)-ATPase and H(+)/K(+)-ATPase. Na(+)/K(+)-ATPase is ubiquitously expressed and has been implicated in several neurological diseases, whereas H(+)/K(+)-ATPase is found principally in the colon, stomach, and kidney. Both ATPases have two subunits, α and β, but Na(+)/K(+)-ATPase also has a regulatory subunit called FXYD, which has an important role in cancer. The most important functions of these ATPases are homeostasis, potassium regulation, and maintaining a gradient in different cell types, like epithelial cells. Na(+)/K(+)-ATPase has become a center of attention ever since it was proposed that it might play a crucial role in neurological disorders such as bipolar disorder, mania, depression, familial hemiplegic migraine, rapid-onset dystonia parkinsonism, chronic stress, epileptogenesis, and Alzheimer's disease. On the other hand, it has been reported that lithium could have a neuroprotective effect against ouabain, which is the best known Na(+)/K(+)-ATPase inhibitor, but and high concentrations of lithium could affect negatively H(+)/K(+)-ATPase activity, that has a key role in regulating acidosis and potassium deficiencies. Finally, potassium homeostasis regulation is composed of two main mechanisms, extrarenal and renal. Extrarenal mechanism controls plasma levels, shifting potassium from the extracellular to the intracellular, whereas renal mechanism concerns with body balance and is influenced by potassium intake and its urinary excretion. In this article, we discuss the functions, isoforms, and localization of P2C-type ATPases, describe some of their modulators, and discuss their implications in some diseases. PMID:25631710

  17. γ-Tilmanocept, a New Radiopharmaceutical Tracer for Cancer Sentinel Lymph Nodes, Binds to the Mannose Receptor (CD206).

    PubMed

    Azad, Abul K; Rajaram, Murugesan V S; Metz, Wendy L; Cope, Frederick O; Blue, Michael S; Vera, David R; Schlesinger, Larry S

    2015-09-01

    γ-Tilmanocept ((99m)Tc-labeled-tilmanocept or [(99m)Tc]-tilmanocept) is the first mannose-containing, receptor-directed, radiolabeled tracer for the highly sensitive imaging of sentinel lymph nodes in solid tumor staging. To elucidate the mannose-binding receptor that retains tilmanocept in this microenvironment, human macrophages were used that have high expression of the C-type lectin mannose receptor (MR; CD206). Cy3-labeled tilmanocept exhibited high specificity binding to macrophages that was nearly abolished in competitive inhibition experiments. Furthermore, Cy3-tilmanocept binding was markedly reduced on macrophages deficient in the MR by small interfering RNA treatment and was increased on MR-transfected HEK 293 cells. Finally, confocal microscopy revealed colocalization of Cy3-tilmanocept with the macrophage membrane MR and binding of labeled tilmanocept to MR(+) cells (macrophages and/or dendritic cells) in human sentinel lymph node tissues. Together these data provide strong evidence that CD206 is a major binding receptor for γ-tilmanocept. Identification of CD206 as the γ-tilmanocept-binding receptor enables opportunities for designing receptor-targeted advanced imaging agents and therapeutics for cancer and other diseases.

  18. Histological and lectin histochemical studies on the olfactory mucosae of the Korean roe deer, Capreolus pygargus.

    PubMed

    Park, Changnam; Ahn, Meejung; Kim, Jeongtae; Kim, Seungjoon; Moon, Changjong; Shin, Taekyun

    2015-04-01

    The morphological features of the olfactory mucosae of Korean roe deer, Capreolus pygargus, were histologically studied using the ethmoid turbinates containing the olfactory mucosae from six roe deer (male, 2-3 years old). The ethmoid turbinates were embedded in paraffin, and histochemically evaluated in terms of the mucosal characteristics. Lectin histochemistry was performed to investigate the carbohydrate-binding specificity on the olfactory mucosa. Lectins, including Triticum vulgaris wheat germ agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), and soybean agglutinin (SBA) were used for the N-acetylglucosamine, fucose and N-acetylgalactosamine carbohydrate groups, respectively. Histologically, the olfactory mucosa, positioned mainly in the caudal roof of the nasal cavity, consisted of the olfactory epithelium and the lamina propria. The olfactory epithelium consisted of protein gene product (PGP) 9.5-positive olfactory receptor cells, galectin-3-positive supporting cells and basal cells. Bowman's glands in the lamina propria were stained by both the periodic acid Schiff reagent and alcian blue (pH 2.5). Two types of lectin, WGA and SBA, were labeled in free border, receptor cells, supporting cells and Bowman's glands, with the exception of basal cells, while UEA-I was labeled in free border, supporting cells and Bowman's glands, but not in receptor cells and basal cells, suggesting that carbohydrate terminals on the olfactory mucosae of roe deer vary depending on cell type. This is the first morphological study of the olfactory mucosa of the Korean roe deer to evaluate carbohydrate terminals in the olfactory mucosae.

  19. Lectin affinity chromatography of glycolipids

    SciTech Connect

    Torres, B.V.; Smith, D.F.

    1987-05-01

    Since glycolipids (GLs) are either insoluble or form mixed micelles in water, lectin affinity chromatography in aqueous systems has not been applied to their separation. They have overcome this problem by using tetrahydrofuran (THF) in the mobile phase during chromatography. Affinity columns prepared with the GalNAc-specific Helix pomatia agglutinin (HPA) and equilibrated in THF specifically bind the (/sup 3/H)oligosaccharide derived from Forssman GL indicating that the immobilized HPA retained its carbohydrate-binding specificity in this solvent. Intact Forssman GL was bound by the HPA-column equilibrated in THF and was specifically eluted with 0.1 mg/ml GalNAc in THF. Purification of the Forssman GL was achieved when a crude lipid extract of sheep erythrocyte membranes was applied to the HPA-column in THF. Non-specifically bound GLs were eluted from the column using a step gradient of aqueous buffer in THF, while the addition of GalNAc was required to elute the specifically bound GLs. Using this procedure the A-active GLs were purified from a crude lipid extract of type A human erythrocytes in a single chromatographic step. The use of solvents that maintain carbohydrate-binding specificity and lipid solubility will permit the application of affinity chromatography on immobilized carbohydrate-binding proteins to intact GLs.

  20. The lectin ArtinM binds to mast cells inducing cell activation and mediator release.

    PubMed

    Barbosa-Lorenzi, Valéria Cintra; Buranello, Patrícia Andressa de Almeida; Roque-Barreira, Maria Cristina; Jamur, Maria Célia; Oliver, Constance; Pereira-da-Silva, Gabriela

    2011-12-16

    Mast cells are inflammatory cells that respond to signals of innate and adaptive immunity with immediate and delayed release of mediators. ArtinM, a lectin from Artocarpus integrifolia with immunomodulatory activities, is able to induce mast cell activation, but the mechanisms remain unknown. This study sought to further investigate the effects of the lectin on mast cells. We showed that ArtinM binds to mast cells, possibly to the high affinity receptor for immunoglobulin E (IgE) - FcεRI - and/or to IgE bound to FcεRI. Binding of the lectin resulted in protein tyrosine phosphorylation and release of the pre- and newly-formed mediators, β-hexosaminidase and LTB(4) by mast cells, activities that were potentiated in the presence of IgE. ArtinM also induced the activation of the transcription factors NFκB and NFAT, resulting in expression of some of their target genes such as IL-4 and TNF-α. In view of the established significance of mast cells in many immunological and inflammatory reactions, a better understanding of the mechanisms involved in mast cell activation by ArtinM is crucial to the pharmacological application of the lectin.

  1. Determination of sugar specificity of jackfruit lectin by a simple sugar-lectin binding assay using microtiter plate.

    PubMed

    Wetprasit, N; Chulavatnatol, M

    1997-06-01

    Sugar-lectin binding assay was developed as a simple method which employed direct coating of microtiter plate with galactose-binding lectins. Biotin-galactose conjugate was used to bind to the immobilized lectins. The bound conjugate was then detected using streptavidin-horseradish peroxidase. Using the assay in conjunction with various competing carbohydrates, jackfruit lectin from Artocarpus heterophyllus was found to be specific for alpha-anomer of galactoside with an aromatic residue.

  2. Role of Lectins in Plant-Microorganism Interactions

    PubMed Central

    Pueppke, Steven G.; Bauer, Wolfgang D.; Keegstra, Kenneth; Ferguson, Ardene L.

    1978-01-01

    Three different assay procedures have been used to quantitate the levels of soybean (Glycine max [L.] Merr.) lectin in various tissues of soybean plants. The assays used were a standard hemagglutination assay, a radioimmunoassay, and an isotope dilution assay. Most of the lectin in seeds was found in the cotyledons, but lectin was also detected in the embryo axis and the seed coat. Soybean lectin was present in all of the tissues of young seedlings, but decreased as the plants matured and was not detectable in plants older than 2 to 3 weeks. Soybean lectin isolated from seeds of several soybean varieties were identical when compared by several methods. PMID:16660384

  3. Combined Bacteria Microarray and Quartz Crystal Microbalance Approach for Exploring Glycosignatures of Nontypeable Haemophilus influenzae and Recognition by Host Lectins.

    PubMed

    Kalograiaki, Ioanna; Euba, Begoña; Proverbio, Davide; Campanero-Rhodes, María A; Aastrup, Teodor; Garmendia, Junkal; Solís, Dolores

    2016-06-01

    Recognition of bacterial surface epitopes by host receptors plays an important role in the infectious process and is intimately associated with bacterial virulence. Delineation of bacteria-host interactions commonly relies on the detection of binding events between purified bacteria- and host-target molecules. In this work, we describe a combined microarray and quartz crystal microbalance (QCM) approach for the analysis of carbohydrate-mediated interactions directly on the bacterial surface, thus preserving the native environment of the bacterial targets. Nontypeable Haemophilus influenzae (NTHi) was selected as a model pathogenic species not displaying a polysaccharide capsule or O-antigen-containing lipopolysaccharide, a trait commonly found in several important respiratory pathogens. Here, we demonstrate the usefulness of NTHi microarrays for exploring the presence of carbohydrate structures on the bacterial surface. Furthermore, the microarray approach is shown to be efficient for detecting strain-selective binding of three innate immune lectins, namely, surfactant protein D, human galectin-8, and Siglec-14, to different NTHi clinical isolates. In parallel, QCM bacteria-chips were developed for the analysis of lectin-binding kinetics and affinity. This novel QCM approach involves capture of NTHi on lectin-derivatized chips followed by formaldehyde fixation, rendering the bacteria an integrated part of the sensor chip, and subsequent binding assays with label-free lectins. The binding parameters obtained for selected NTHi-lectin pairs provide further insights into the interactions occurring at the bacterial surface.

  4. Combined Bacteria Microarray and Quartz Crystal Microbalance Approach for Exploring Glycosignatures of Nontypeable Haemophilus influenzae and Recognition by Host Lectins.

    PubMed

    Kalograiaki, Ioanna; Euba, Begoña; Proverbio, Davide; Campanero-Rhodes, María A; Aastrup, Teodor; Garmendia, Junkal; Solís, Dolores

    2016-06-01

    Recognition of bacterial surface epitopes by host receptors plays an important role in the infectious process and is intimately associated with bacterial virulence. Delineation of bacteria-host interactions commonly relies on the detection of binding events between purified bacteria- and host-target molecules. In this work, we describe a combined microarray and quartz crystal microbalance (QCM) approach for the analysis of carbohydrate-mediated interactions directly on the bacterial surface, thus preserving the native environment of the bacterial targets. Nontypeable Haemophilus influenzae (NTHi) was selected as a model pathogenic species not displaying a polysaccharide capsule or O-antigen-containing lipopolysaccharide, a trait commonly found in several important respiratory pathogens. Here, we demonstrate the usefulness of NTHi microarrays for exploring the presence of carbohydrate structures on the bacterial surface. Furthermore, the microarray approach is shown to be efficient for detecting strain-selective binding of three innate immune lectins, namely, surfactant protein D, human galectin-8, and Siglec-14, to different NTHi clinical isolates. In parallel, QCM bacteria-chips were developed for the analysis of lectin-binding kinetics and affinity. This novel QCM approach involves capture of NTHi on lectin-derivatized chips followed by formaldehyde fixation, rendering the bacteria an integrated part of the sensor chip, and subsequent binding assays with label-free lectins. The binding parameters obtained for selected NTHi-lectin pairs provide further insights into the interactions occurring at the bacterial surface. PMID:27176788

  5. Fruit-specific lectins from banana and plantain.

    PubMed

    Peumans, W J; Zhang, W; Barre, A; Houlès Astoul, C; Balint-Kurti, P J; Rovira, P; Rougé, P; May, G D; Van Leuven, F; Truffa-Bachi, P; Van Damme, E J

    2000-09-01

    One of the predominant proteins in the pulp of ripe bananas (Musa acuminata L.) and plantains (Musa spp.) has been identified as a lectin. The banana and plantain agglutinins (called BanLec and PlanLec, respectively) were purified in reasonable quantities using a novel isolation procedure, which prevented adsorption of the lectins onto insoluble endogenous polysaccharides. Both BanLec and PlanLec are dimeric proteins composed of two identical subunits of 15 kDa. They readily agglutinate rabbit erythrocytes and exhibit specificity towards mannose. Molecular cloning revealed that BanLec has sequence similarity to previously described lectins of the family of jacalin-related lectins, and according to molecular modelling studies has the same overall fold and three-dimensional structure. The identification of BanLec and PlanLec demonstrates the occurrence of jacalin-related lectins in monocot species, suggesting that these lectins are more widespread among higher plants than is actually believed. The banana and plantain lectins are also the first documented examples of jacalin-related lectins, which are abundantly present in the pulp of mature fruits but are apparently absent from other tissues. However, after treatment of intact plants with methyl jasmonate, BanLec is also clearly induced in leaves. The banana lectin is a powerful murine T-cell mitogen. The relevance of the mitogenicity of the banana lectin is discussed in terms of both the physiological role of the lectin and the impact on food safety.

  6. Mushroom lectins: specificity, structure and bioactivity relevant to human disease.

    PubMed

    Hassan, Mohamed Ali Abol; Rouf, Razina; Tiralongo, Evelin; May, Tom W; Tiralongo, Joe

    2015-04-08

    Lectins are non-immunoglobulin proteins that bind diverse sugar structures with a high degree of selectivity. Lectins play crucial role in various biological processes such as cellular signaling, scavenging of glycoproteins from the circulatory system, cell-cell interactions in the immune system, differentiation and protein targeting to cellular compartments, as well as in host defence mechanisms, inflammation, and cancer. Among all the sources of lectins, plants have been most extensively studied. However, more recently fungal lectins have attracted considerable attention due to their antitumor, antiproliferative and immunomodulatory activities. Given that only 10% of mushroom species are known and have been taxonomically classified, mushrooms represent an enormous unexplored source of potentially useful and novel lectins. In this review we provide an up-to-date summary on the biochemical, molecular and structural properties of mushroom lectins, as well as their versatile applications specifically focusing on mushroom lectin bioactivity.

  7. Comprehensive list of lectins: origins, natures, and carbohydrate specificities.

    PubMed

    Kobayashi, Yuka; Tateno, Hiroaki; Ogawa, Haruko; Yamamoto, Kazuo; Hirabayashi, Jun

    2014-01-01

    More than 100 years have passed since the first lectin ricin was discovered. Since then, a wide variety of lectins (lect means "select" in Latin) have been isolated from plants, animals, fungi, bacteria, as well as viruses, and their structures and properties have been characterized. At present, as many as 48 protein scaffolds have been identified as functional lectins from the viewpoint of three-dimensional structures as described in this chapter. In this chapter, representative 53 lectins are selected, and their major properties that include hemagglutinating activity, mitogen activity, blood group specificity, molecular weight, metal requirement, and sugar specificities are summarized as a comprehensive table. The list will provide a practically useful, comprehensive list for not only experienced lectin users but also many other non-expert researchers, who are not familiar to lectins and, therefore, have no access to advanced lectin biotechnologies described in other chapters. PMID:25117264

  8. Mushroom Lectins: Specificity, Structure and Bioactivity Relevant to Human Disease

    PubMed Central

    Hassan, Mohamed Ali Abol; Rouf, Razina; Tiralongo, Evelin; May, Tom W.; Tiralongo, Joe

    2015-01-01

    Lectins are non-immunoglobulin proteins that bind diverse sugar structures with a high degree of selectivity. Lectins play crucial role in various biological processes such as cellular signaling, scavenging of glycoproteins from the circulatory system, cell–cell interactions in the immune system, differentiation and protein targeting to cellular compartments, as well as in host defence mechanisms, inflammation, and cancer. Among all the sources of lectins, plants have been most extensively studied. However, more recently fungal lectins have attracted considerable attention due to their antitumor, antiproliferative and immunomodulatory activities. Given that only 10% of mushroom species are known and have been taxonomically classified, mushrooms represent an enormous unexplored source of potentially useful and novel lectins. In this review we provide an up-to-date summary on the biochemical, molecular and structural properties of mushroom lectins, as well as their versatile applications specifically focusing on mushroom lectin bioactivity. PMID:25856678

  9. Non-labeled QCM Biosensor for Bacterial Detection using Carbohydrate and Lectin Recognitions

    PubMed Central

    Shen, Zhihong; Huang, Mingchuan; Xiao, Caide; Zhang, Yun; Zeng, Xiangqun; Wang, Peng G.

    2008-01-01

    also increases the binding of bacteria to their carbohydrate receptor through bacterial surface binding lectins that significantly enhanced specificity and sensitivity of QCM biosensors. Combining carbohydrate and lectin recognition events with an appropriate QCM transducer can yield sensor devices highly suitable for the fast, reversible and straightforward on-line screening and detection of bacteria in food, water, clinical and biodefense areas. PMID:17295446

  10. Binding of isolated plant lectin by rhizobia during episodes of reduced gravity obtained by parabolic flight

    NASA Technical Reports Server (NTRS)

    Henry, R. L.; Green, P. D.; Wong, P. P.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

    1990-01-01

    Development of a legume root nodule is a complex process culminating in a plant/bacterial symbiosis possessing the capacity for biological dinitrogen fixation. Formation of root nodules is initiated by the binding and stabilization of rhizobia to plant root hairs, mediated in part by a receptor/ligand recognition system composed of lectins on the plant root surface and lectin-binding sites on the rhizobial cell surface. The dinitrogen fixation activity of these root nodules may be an important feature of enclosed, space-based life support systems, and may provide an ecological method to recycle nitrogen for amino acid production. However, the effects on nodule development of varied gravitational fields, or of root nutrient delivery hardware, remain unknown. We have investigated the effects of microgravity on root nodule formation, with preliminary experiments focused upon the receptor/ligand component. Microgravity, obtained during parabolic flight aboard NASA 930, has no apparent effect on the binding of purified lectin to rhizobia, a result that will facilitate forthcoming experiments using intact root tissues.

  11. In silico analysis of molecular mechanisms of Galanthus nivalis agglutinin-related lectin-induced cancer cell death from carbohydrate-binding motif evolution hypothesis.

    PubMed

    Yu, Qi-Jia; Li, Zi-Yue; Yao, Shun; Ming, Miao; Wang, Shu-Ya; Liu, Bo; Bao, Jin-Ku

    2011-10-01

    Galanthus nivalis agglutinin-related lectins, a superfamily of strictly mannose-binding-specific lectins widespread amongst monotyledonous plants, have drawn a rising attention for their remarkable anti-proliferative and apoptosis-inducing activities toward various types of cancer cells; however, the precise molecular mechanisms by which they induce tumor cell apoptosis are still only rudimentarily understood. Herein, we found that the three conserved motifs "QXDXNXVXY," the mannose-specific binding sites, could mutate at one or more amino acid sites, which might be a driving force for the sequential evolution and thus ultimately leading to the complete disappearance of the three conserved motifs. In addition, we found that the motif evolution could result in the diversification of sugar-binding types that G. nivalis agglutinin-related lectins could bind from specific mannose receptors to more types of sugar-containing receptors in cancer cells. Subsequently, we indicated that some sugar-containing receptors such as TNFR1, EGFR, Hsp90, and Hsp70 could block downstream anti-apoptotic or survival signaling pathways, which, in turn, resulted in tumor cell apoptosis. Taken together, our hypothesis that carbohydrate-binding motif evolution may impact the G. nivalis agglutinin-related lectin-induced survival or anti-apoptotic pathways would provide a new perspective for further elucidating the intricate relationships between the carbohydrate-binding specificities and complex molecular mechanisms by which G. nivalis agglutinin-related lectins induce cancer cell death.

  12. Lectin genes in the Frankia alni genome.

    PubMed

    Pujic, Petar; Fournier, Pascale; Alloisio, Nicole; Hay, Anne-Emmanuelle; Maréchal, Joelle; Anchisi, Stéphanie; Normand, Philippe

    2012-01-01

    Frankia alni strain ACN14a's genome was scanned for the presence of determinants involved in interactions with its host plant, Alnus spp. One such determinant type is lectin, proteins that bind specifically to sugar motifs. The genome of F. alni was found to contain 7 such lectin-coding genes, five of which were of the ricinB-type. The proteins coded by these genes contain either only the lectin domain, or also a heat shock protein or a serine-threonine kinase domain upstream. These lectins were found to have several homologs in Streptomyces spp., and a few in other bacterial genomes among which none in Frankia EAN1pec and CcI3 and two in strain EUN1f. One of these F. alni genes, FRAAL0616, was cloned in E. coli, fused with a reporter gene yielding a fusion protein that was found to bind to both root hairs and to bacterial hyphae. This protein was also found to modify the dynamics of nodule formation in A. glutinosa, resulting in a higher number of nodules per root. Its role could thus be to permit binding of microbial cells to root hairs and help symbiosis to occur under conditions of low Frankia cell counts such as in pioneer situations. PMID:22159868

  13. Development and Applications of the Lectin Microarray.

    PubMed

    Hirabayashi, Jun; Kuno, Atsushi; Tateno, Hiroaki

    2015-01-01

    The lectin microarray is an emerging technology for glycomics. It has already found maximum use in diverse fields of glycobiology by providing simple procedures for differential glycan profiling in a rapid and high-throughput manner. Since its first appearance in the literature in 2005, many application methods have been developed essentially on the same platform, comprising a series of glycan-binding proteins immobilized on an appropriate substrate such as a glass slide. Because the lectin microarray strategy does not require prior liberation of glycans from the core protein in glycoprotein analysis, it should encourage researchers not familiar with glycotechnology to use glycan analysis in future work. This feasibility should provide a broader range of experimental scientists with good opportunities to investigate novel aspects of glycoscience. Applications of the technology include not only basic sciences but also the growing fields of bio-industry. This chapter describes first the essence of glycan profiling and the basic fabrication of the lectin microarray for this purpose. In the latter part the focus is on diverse applications to both structural and functional glycomics, with emphasis on the wide applicability now available with this new technology. Finally, the importance of developing advanced lectin engineering is discussed.

  14. Jacalin: an IgA-binding lectin.

    PubMed

    Roque-Barreira, M C; Campos-Neto, A

    1985-03-01

    We previously reported that seeds of Artocarpus integrifolia (jackfruit) contain a lectin, which we call jacalin, that is both a potent T cell mitogen and an apparently T cell-independent activator of human B cells for the secretion of immunoglobulins. During the above experiments we noted a massive precipitation in cell cultures stimulated with greater than or equal to 100 micrograms of lectin. In this paper, we show that the precipitate is formed after the interaction of jacalin and the serum protein added to the culture medium. More importantly, we demonstrate that IgA is probably the major serum constituent precipitated by the lectin and that no IgG or IgM can be detected in the precipitates. In secretions such as colostrum, IgA is the only protein precipitated by jacalin. On the basis of this specificity we describe a simple and reliable affinity chromatography procedure for the purification of both human serum and colostrum IgA. Jacalin is a D-Gal binding lectin and should be a useful tool for studying of serum and secretory IgA.

  15. A mushroom lectin from ascomycete Cordyceps militaris.

    PubMed

    Jung, Eui Cha; Kim, Ki Don; Bae, Chan Hyung; Kim, Ju Cheol; Kim, Dae Kyong; Kim, Ha Hyung

    2007-05-01

    A mushroom lectin has been purified from ascomycete Cordyceps militaris, which is one of the most popular mushrooms in eastern Asia used as a nutraceutical and in traditional Chinese medicine. This lectin, designated CML, exhibited hemagglutination activity in mouse and rat erythrocytes, but not in human ABO erythrocytes. SDS-PAGE of CML revealed a single band with a molecular mass of 31.0 kDa under both nonreducing and reducing conditions that was stained by silver nitrate, and a 31.4 kDa peak in a Superdex-200 HR gel-filtration column. The hemagglutination activity was inhibited by sialoglycoproteins, but not in by mono- or disaccharides, asialoglycoproteins, or de-O-acetylated glycoprotein. The activity was maximal at pH 6.0-9.1 and at temperatures below 50 degrees C. Circular dichroism spectrum analysis revealed that CML comprises 27% alpha-helix, 12% beta-sheets, 29% beta-turns, and 32% random coils. Its binding specificity and secondary structure are similar to those of a fungal lectin from Arthrobotrys oligospora. However, the N-terminal amino acid sequence of CML differs greatly from those of other lectins. CML exhibits mitogenic activity against mouse splenocytes. PMID:17306462

  16. Legume Lectin FRIL Preserves Neural Progenitor Cells in Suspension Culture In Vitro

    PubMed Central

    Yao, Hailei; Xie, Xiaoyan; Li, Yanhua; Wang, Dongmei; Han, Shu; Shi, Shuangshuang; Nan, Xue; Bai, Cixian; Wang, Yunfang; Pei, Xuetao

    2008-01-01

    In vitro maintenance of stem cells is crucial for many clinical applications. Stem cell preservation factor FRIL (Flt3 receptor-interacting lectin) is a plant lectin extracted from Dolichos Lablab and has been found preserve hematopoietic stem cells in vitro for a month in our previous studies. To investigate whether FRIL can preserve neural progenitor cells (NPCs), it was supplemented into serum-free suspension culture media. FRIL made NPC grow slowly, induced cell adhesion, and delayed neurospheres formation. However, FRIL did not initiate NPC differentiation according to immunofluorescence and semiquantitive RT-PCR results. In conclusion, FRIL could also preserve neural progenitor cells in vitro by inhibiting both cell proliferation and differentiation. PMID:18695740

  17. Displacement phenomena in lectin affinity chromatography.

    PubMed

    Cho, Wonryeon

    2015-10-01

    The work described here examines displacement phenomena that play a role in lectin affinity chromatography and their potential to impact reproducibility. This was achieved using Lycopersicon esculentum lectin (LEL), a lectin widely used in monitoring cancer. Four small identical LEL columns were coupled in series to form a single affinity chromatography system with the last in the series connected to an absorbance detector. The serial affinity column set (SACS) was then loaded with human plasma proteins. At the completion of loading, the column set was disassembled, the four columns were eluted individually, the captured proteins were trypsin digested, the peptides were deglycosylated with PNGase F, and the parent proteins were identified through mass spectral analyses. Significantly different sets of glycoproteins were selected by each column, some proteins appearing to be exclusively bound to the first column while others were bound further along in the series. Clearly, sample displacement chromatography (SDC) occurs. Glycoproteins were bound at different places in the column train, identifying the presence of glycoforms with different affinity on a single glycoprotein. It is not possible to see these phenomena in the single column mode of chromatography. Moreover, low abundance proteins were enriched, which facilitates detection. The great advantage of this method is that it differentiates between glycoproteins on the basis of their binding affinity. Displacement phenomena are concluded to be a significant component of the separation mechanism in heavily loaded lectin affinity chromatography columns. This further suggests that care must be exercised in sample loading of lectin columns to prevent analyte displacement with nonretained proteins. PMID:26348026

  18. Effect of lectins on hepatic clearance and killing of Candida albicans by the isolated perfused mouse liver.

    PubMed Central

    Sawyer, R T; Garner, R E; Hudson, J A

    1992-01-01

    The isolated perfused mouse liver model was used to study the effects of various lectins on hepatic trapping and killing of Candida albicans. After mouse livers were washed with 20 to 30 ml of perfusion buffer, 10(6) C. albicans CFU were infused into the livers. At the time of recovery, 63% +/- 2% (mean +/- standard error of the mean) of the infused C. albicans CFU were recovered from the liver and 14% +/- 1% were recovered from the effluent for a total recovery of 77% +/- 2%. This indicated that 86% +/- 9% of the original inoculum was trapped by the liver and that 23% +/- 2% was killed within the liver. When included in both preperfusion and postperfusion buffers (0.2 mg of lectin per ml), Ulex europeaus lectin (binding specificity for fucose) decreased hepatic trapping of C. albicans by 37% and eluted trapped C. albicans from the liver only when included in postperfusion buffer. By comparison, treatment of C. albicans with U. europeaus lectin before infusion had no effect on the trapping or killing of yeast cells. When Lens culinaris lectin (binding specificity for mannose) was included in the perfusion buffers, hepatic killing of C. albicans increased by 16% with no significant effect on hepatic killing when yeast cells were treated with L. culinaris lectin before infusion. Forty to 55% of the infused C. albicans were killed when concanavalin A (binding specificities for mannose and glucose), Glycine max (binding specificity for N-acetylgalactosamine), or Arachis hypogea (binding specificity for galactose) lectin was included in the perfusion buffer or when yeast cells were treated with these lectins before their infusion. When C. albicans was treated with concanavalin A at a concentration of less than 0.02 mg/ml, hepatic killing of yeast cells was not significantly increased. The data suggest that a fucose-containing receptor on the surface of either sinusoidal endothelial cells or Kupffer cells is involved in the trapping of C. albicans by the perfused mouse

  19. Effect of lectins on hepatic clearance and killing of Candida albicans by the isolated perfused mouse liver.

    PubMed

    Sawyer, R T; Garner, R E; Hudson, J A

    1992-03-01

    The isolated perfused mouse liver model was used to study the effects of various lectins on hepatic trapping and killing of Candida albicans. After mouse livers were washed with 20 to 30 ml of perfusion buffer, 10(6) C. albicans CFU were infused into the livers. At the time of recovery, 63% +/- 2% (mean +/- standard error of the mean) of the infused C. albicans CFU were recovered from the liver and 14% +/- 1% were recovered from the effluent for a total recovery of 77% +/- 2%. This indicated that 86% +/- 9% of the original inoculum was trapped by the liver and that 23% +/- 2% was killed within the liver. When included in both preperfusion and postperfusion buffers (0.2 mg of lectin per ml), Ulex europeaus lectin (binding specificity for fucose) decreased hepatic trapping of C. albicans by 37% and eluted trapped C. albicans from the liver only when included in postperfusion buffer. By comparison, treatment of C. albicans with U. europeaus lectin before infusion had no effect on the trapping or killing of yeast cells. When Lens culinaris lectin (binding specificity for mannose) was included in the perfusion buffers, hepatic killing of C. albicans increased by 16% with no significant effect on hepatic killing when yeast cells were treated with L. culinaris lectin before infusion. Forty to 55% of the infused C. albicans were killed when concanavalin A (binding specificities for mannose and glucose), Glycine max (binding specificity for N-acetylgalactosamine), or Arachis hypogea (binding specificity for galactose) lectin was included in the perfusion buffer or when yeast cells were treated with these lectins before their infusion. When C. albicans was treated with concanavalin A at a concentration of less than 0.02 mg/ml, hepatic killing of yeast cells was not significantly increased. The data suggest that a fucose-containing receptor on the surface of either sinusoidal endothelial cells or Kupffer cells is involved in the trapping of C. albicans by the perfused mouse

  20. Synthesis of high-mannose oligosaccharide analogues through click chemistry: true functional mimics of their natural counterparts against lectins?

    PubMed

    François-Heude, Marc; Méndez-Ardoy, Alejandro; Cendret, Virginie; Lafite, Pierre; Daniellou, Richard; Ortiz Mellet, Carmen; García Fernández, José M; Moreau, Vincent; Djedaïni-Pilard, Florence

    2015-01-26

    Terminal "high-mannose oligosaccharides" are involved in a broad range of biological and pathological processes, from sperm-egg fusion to influenza and human immunodeficiency virus infections. In spite of many efforts, their synthesis continues to be very challenging and actually represents a major bottleneck in the field. Whereas multivalent presentation of mannopyranosyl motifs onto a variety of scaffolds has proven to be a successful way to interfere in recognition processes involving high-mannose oligosaccharides, such constructs fail at reproducing the subtle differences in affinity towards the variety of protein receptors (lectins) and antibodies susceptible to binding to the natural ligands. Here we report a family of functional high-mannose oligosaccharide mimics that reproduce not only the terminal mannopyranosyl display, but also the core structure and the branching pattern, by replacing some inner mannopyranosyl units with triazole rings. Such molecular design can be implemented by exploiting "click" ligation strategies, resulting in a substantial reduction of synthetic cost. The binding affinities of the new "click" high-mannose oligosaccharide mimics towards two mannose specific lectins, namely the plant lectin concanavalin A (ConA) and the human macrophage mannose receptor (rhMMR), have been studied by enzyme-linked lectin assays and found to follow identical trends to those observed for the natural oligosaccharide counterparts. Calorimetric determinations against ConA, and X-ray structural data support the conclusion that these compounds are not just another family of multivalent mannosides, but real "structural mimics" of the high-mannose oligosaccharides.

  1. Using Single Lectins to Enrich Glycoproteins in Conditioned Media.

    PubMed

    Sethi, Manveen K; Fanayan, Susan

    2015-08-03

    Lectins are sugar-binding proteins that can recognize and bind to carbohydrates conjugated to proteins and lipids. Coupled with mass spectrometry technologies, lectin affinity chromatography is becoming a popular approach for identification and quantification of glycoproteins in complex samples such as blood, tumor tissues, and cell lines. Given the commercial availability of a large number of lectins that recognize diverse sugar structures, it is now possible to isolate and study glycoproteins for biological and medical research. This unit provides a general guide to single-lectin-based enrichment of glycoproteins from serum-free conditioned media. Due to the unique carbohydrate specificity of most lectins and the complexity of the samples, optimization steps may be required to evaluate different elution buffers and methods as well as binding conditions, for each lectin, for optimal recovery of bound glycoproteins.

  2. Closed state-coupled C-type inactivation in BK channels.

    PubMed

    Yan, Jiusheng; Li, Qin; Aldrich, Richard W

    2016-06-21

    Ion channels regulate ion flow by opening and closing their pore gates. K(+) channels commonly possess two pore gates, one at the intracellular end for fast channel activation/deactivation and the other at the selectivity filter for slow C-type inactivation/recovery. The large-conductance calcium-activated potassium (BK) channel lacks a classic intracellular bundle-crossing activation gate and normally show no C-type inactivation. We hypothesized that the BK channel's activation gate may spatially overlap or coexist with the C-type inactivation gate at or near the selectivity filter. We induced C-type inactivation in BK channels and studied the relationship between activation/deactivation and C-type inactivation/recovery. We observed prominent slow C-type inactivation/recovery in BK channels by an extreme low concentration of extracellular K(+) together with a Y294E/K/Q/S or Y279F mutation whose equivalent in Shaker channels (T449E/K/D/Q/S or W434F) caused a greatly accelerated rate of C-type inactivation or constitutive C-inactivation. C-type inactivation in most K(+) channels occurs upon sustained membrane depolarization or channel opening and then recovers during hyperpolarized membrane potentials or channel closure. However, we found that the BK channel C-type inactivation occurred during hyperpolarized membrane potentials or with decreased intracellular calcium ([Ca(2+)]i) and recovered with depolarized membrane potentials or elevated [Ca(2+)]i Constitutively open mutation prevented BK channels from C-type inactivation. We concluded that BK channel C-type inactivation is closed state-dependent and that its extents and rates inversely correlate with channel-open probability. Because C-type inactivation can involve multiple conformational changes at the selectivity filter, we propose that the BK channel's normal closing may represent an early conformational stage of C-type inactivation.

  3. Lectin cDNA and transgenic plants derived therefrom

    DOEpatents

    Raikhel, N.V.

    1994-01-04

    Transgenic plants containing cDNA encoding Gramineae lectin are described. The plants preferably contain cDNA coding for barley lectin and store the lectin in the leaves. The transgenic plants, particularly the leaves exhibit insecticidal and fungicidal properties. GOVERNMENT RIGHTS This application was funded under Department of Energy Contract DE-AC02-76ER01338. The U.S. Government has certain rights under this application and any patent issuing thereon. .

  4. Lectin cDNA and transgenic plants derived therefrom

    DOEpatents

    Raikhel, Natasha V.

    1994-01-04

    Transgenic plants containing cDNA encoding Gramineae lectin are described. The plants preferably contain cDNA coding for barley lectin and store the lectin in the leaves. The transgenic plants, particularly the leaves exhibit insecticidal and fungicidal properties. GOVERNMENT RIGHTS This application was funded under Department of Energy Contract DE-AC02-76ER01338. The U.S. Government has certain rights under this application and any patent issuing thereon.

  5. ON VASCULAR STENOSIS, RESTENOSIS AND MANNOSE BINDING LECTIN

    PubMed Central

    KAHLOW, Barbara Stadler; NERY, Rodrigo Araldi; SKARE, Thelma L; RIBAS, Carmen Australia Paredes Marcondes; RAMOS, Gabriela Piovezani; PETISCO, Roberta Dombroski

    2016-01-01

    Mannose binding lectin is a lectin instrumental in the innate immunity. It recognizes carbohydrate patterns found on the surface of a large number of pathogenic micro-organisms, activating the complement system. However, this protein seems to increase the tissue damage after ischemia. In this paper is reviewed some aspects of harmful role of the mannose binding lectin in ischemia/reperfusion injury. PMID:27120743

  6. Mannose-binding lectin in HIV infection

    PubMed Central

    Eisen, Sarah; Dzwonek, Agnieszka; Klein, Nigel J

    2010-01-01

    Infection with HIV represents a significant global health problem, with high infection rates and high mortality worldwide. Treatment with antiretroviral therapy is inaccessible to many patients and efficacy is limited by development of resistance and side effects. The interactions of HIV with the human immune system, both innate and humoral, are complex and complicated by the profound ability of the virus to disable the host immune response. Mannose-binding lectin, a component of the innate immune system, has been demonstrated to play a role in host-virus interactions. This protein may have a key role in determining host susceptibility to infection, pathogenesis and progression of disease, and may contribute to the extensive variability of host response to infection. Further understanding and manipulation of the mannose-binding lectin response may represent a target for immunomodulation in HIV infection, which may, in conjunction with highly active antiretroviral therapy, allow development of a novel therapeutic approach to HIV infection. PMID:21218140

  7. Concept, strategy and realization of lectin-based glycan profiling.

    PubMed

    Hirabayashi, Jun

    2008-08-01

    Lectins are a diverse group of carbohydrate-binding proteins. Each lectin has its own specificity profile. It is believed that lectins exist in all living organisms that produce glycans. From a practical viewpoint, lectins have been used extensively in biochemical fields including proteomics due to their usefulness as detection and enrichment tools for specific glycans. Nevertheless, they have often been underestimated as probes, especially compared with antibodies, because of their low affinity and broad specificity. However, together with the concept of glycomics, such properties of lectins are now considered to be suitable for the task of 'profiling' in order to cover a wider range of ligands. Recently there has been rapid movement in the field of proteomics aimed at the investigation of glycan-related biomarkers. This is partly because of limitations of the present approach of simply following changes in protein-level expression, without paying sufficient attention to the fact and effects of glycosylation. The trend is reflected in the frequent use of lectins in the contexts of glycoprotein enrichment and glycan profiling. However, there are many aspects to be considered in using lectins, which differ considerably from antibodies. In this article, the author, as a developer of two unique methodologies, frontal affinity chromatography (FAC) and the lectin microarray, describes critical points concerning the use of lectins, together with the concept, strategy and means to achieve advances in these emerging glycan profiling technologies. PMID:18390573

  8. Are vicilins another major class of legume lectins?

    PubMed

    Ribeiro, Ana C; Monteiro, Sara V; Carrapiço, Belmira M; Ferreira, Ricardo B

    2014-01-01

    Legume lectins comprise a structurally related, Ca/Mn-dependent, widespread, abundant and well characterized lectin family when compared to the large number of lectins from other sources described in the literature. Strangely enough, no specific function has been assigned to them aside from a possible role in storage and/or defense. Using a recent and fine-tuned methodology capable of specific lectin identification, β-conglutin, Vicia faba vicilin and β-lathyrin, the vicilin storage globulins from Lupinus albus, V. faba and Lathyrus sativus, respectively, were shown to be capable of affinity binding to thoroughly washed erythrocyte membranes and of specific elution with appropriate sugars. Based on this evidence and on sparse data published in the literature, a second family of legume lectins is proposed: the 7S family of storage proteins from leguminous seeds, or family II of legume lectins. These lectins are also structurally related, widespread and well characterized. In addition, they self-aggregate in a Ca/Mg, electrostatic dependent manner and are even more abundant than the family I of legume lectins. Using the same evidence, reserve and defense roles may be attributed to family II of legume lectins.

  9. Antifungal properties of lectin and new chitinases from potato tubers.

    PubMed

    Gozia, O; Ciopraga, J; Bentia, T; Lungu, M; Zamfirescu, I; Tudor, R; Roseanu, A; Nitu, F

    1993-08-01

    We have purified from potato tubers, the lectin STA devoid of chitinase activity and two chitinases devoid of lectin activity. Both enzymes are 16 kDa glycoproteins, and probably belong to a new family of plant chitinases. The respective antifungal properties of lectin and chitinases were studied by following their effects against early developmental stages of Fusarium oxysporum, a fungal potato pathogen. Here we demonstrate that: (1) lectin does not inhibit mycelial growth but irreversibly inhibits conidia germination and alters the germ tubes; and (2) chitinases block mycelial growth as well as conidia germination and lyse germ tubes.

  10. Human blood dendritic cell subsets exhibit discriminative pattern recognition receptor profiles

    PubMed Central

    Lundberg, Kristina; Rydnert, Frida; Greiff, Lennart; Lindstedt, Malin

    2014-01-01

    Dendritic cells (DCs) operate as the link between innate and adaptive immunity. Their expression of pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) and C-type lectin receptors (CLRs), enables antigen recognition and mediates appropriate immune responses. Distinct subsets of human DCs have been identified; however their expression of PRRs is not fully clarified. Expressions of CLRs by DC subpopulations, in particular, remain elusive. This study aimed to identify and compare PRR expressions on human blood DC subsets, including CD1c+, CD141+ and CD16+ myeloid DCs and CD123+ plasmacytoid DCs, in order to understand their capacity to recognize different antigens as well as their responsiveness to PRR-directed targeting. Whole blood was obtained from 13 allergic and six non-allergic individuals. Mononuclear cells were purified and multi-colour flow cytometry was used to assess the expression of 10 CLRs and two TLRs on distinct DC subsets. PRR expression levels were shown to differ between DC subsets for each PRR assessed. Furthermore, principal component analysis and random forest test demonstrated that the PRR profiles were discriminative between DC subsets. Interestingly, CLEC9A was expressed at lower levels by CD141+ DCs from allergic compared with non-allergic donors. The subset-specific PRR expression profiles suggests individual responsiveness to PRR-targeting and supports functional specialization. PMID:24444310

  11. Human blood dendritic cell subsets exhibit discriminative pattern recognition receptor profiles.

    PubMed

    Lundberg, Kristina; Rydnert, Frida; Greiff, Lennart; Lindstedt, Malin

    2014-06-01

    Dendritic cells (DCs) operate as the link between innate and adaptive immunity. Their expression of pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) and C-type lectin receptors (CLRs), enables antigen recognition and mediates appropriate immune responses. Distinct subsets of human DCs have been identified; however their expression of PRRs is not fully clarified. Expressions of CLRs by DC subpopulations, in particular, remain elusive. This study aimed to identify and compare PRR expressions on human blood DC subsets, including CD1c(+) , CD141(+) and CD16(+) myeloid DCs and CD123(+) plasmacytoid DCs, in order to understand their capacity to recognize different antigens as well as their responsiveness to PRR-directed targeting. Whole blood was obtained from 13 allergic and six non-allergic individuals. Mononuclear cells were purified and multi-colour flow cytometry was used to assess the expression of 10 CLRs and two TLRs on distinct DC subsets. PRR expression levels were shown to differ between DC subsets for each PRR assessed. Furthermore, principal component analysis and random forest test demonstrated that the PRR profiles were discriminative between DC subsets. Interestingly, CLEC9A was expressed at lower levels by CD141(+) DCs from allergic compared with non-allergic donors. The subset-specific PRR expression profiles suggests individual responsiveness to PRR-targeting and supports functional specialization. PMID:24444310

  12. Murine pattern recognition receptor dectin-1 is essential in the development of experimental autoimmune uveoretinitis.

    PubMed

    Stoppelkamp, Sandra; Reid, Delyth M; Yeoh, Joyce; Taylor, Julie; McKenzie, Emma J; Brown, Gordon D; Gordon, Siamon; Forrester, John V; Wong, Simon Y C

    2015-10-01

    Mycobacteria in complete Freund's adjuvant (CFA) are an essential component of immunization protocols in a number of autoimmune disease animal models including experimental autoimmune encephalomyelitis and uveoretinitis (EAE and EAU, respectively). We determined the role in EAU of two C-type lectin receptors on myeloid cells that recognize and respond to mycobacteria. Using receptor-specific antibodies and knockout mice, we demonstrated for the first time that the macrophage mannose receptor delays disease development but does not affect severity. In contrast, dectin-1 is critically involved in the development of CFA-mediated EAU. Disease severity is reduced in dectin-1 knockout mice and antibody blockade of dectin-1 during the induction, but not the effector phase, prevents EAU development. Significantly, similar blockade of dectin-1 in vivo has no effect in non-CFA-mediated, spontaneously induced or adoptive transfer models of EAU. Thus dectin-1 plays a critical role in the ability of complete Freund's adjuvant to induce EAU in mice.

  13. Tomato lectin histochemistry for microglial visualization.

    PubMed

    Villacampa, Nàdia; Almolda, Beatriz; González, Berta; Castellano, Bernardo

    2013-01-01

    The use of different lectins for the study of microglial cells in the central nervous system (CNS) is a valuable tool that has been extensively used in the last years for the selective staining of this glial cell population, not only in normal physiological conditions, but also in a wide range of pathological situations where the normal homeostasis of the parenchyma is disturbed. In this chapter we accurately describe the methodology for the selective labelling of microglial cells by using the tomato lectin (TL), a protein lectin obtained from Lycopersicum esculentum with specific affinity for poly-N-acetyl lactosamine sugar residues which are found on the plasma membrane and in the cytoplasm of microglia. Here we describe how to perform this technique on vibratome, frozen, and paraffin sections for optical microscopy, as well as for transmission electron microscopy (TEM) studies. Using this methodology it is possible to visualize amoeboid microglia in the developing brain, ramified microglia in the adult, and activated/reactive microglia in the experimentally damaged brain. In addition, as TL also recognized sugar residues in endothelial cells, this technique is very useful for the study of the relationship established between microglia and the CNS vasculature. PMID:23813385

  14. Pattern-recognition receptors and gastric cancer.

    PubMed

    Castaño-Rodríguez, Natalia; Kaakoush, Nadeem O; Mitchell, Hazel M

    2014-01-01

    Chronic inflammation has been associated with an increased risk of several human malignancies, a classic example being gastric adenocarcinoma (GC). Development of GC is known to result from infection of the gastric mucosa by Helicobacter pylori, which initially induces acute inflammation and, in a subset of patients, progresses over time to chronic inflammation, gastric atrophy, intestinal metaplasia, dysplasia, and finally intestinal-type GC. Germ-line encoded receptors known as pattern-recognition receptors (PRRs) are critical for generating mature pro-inflammatory cytokines that are crucial for both Th1 and Th2 responses. Given that H. pylori is initially targeted by PRRs, it is conceivable that dysfunction within genes of this arm of the immune system could modulate the host response against H. pylori infection, and subsequently influence the emergence of GC. Current evidence suggests that Toll-like receptors (TLRs) (TLR2, TLR3, TLR4, TLR5, and TLR9), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) (NOD1, NOD2, and NLRP3), a C-type lectin receptor (DC-SIGN), and retinoic acid-inducible gene (RIG)-I-like receptors (RIG-I and MDA-5), are involved in both the recognition of H. pylori and gastric carcinogenesis. In addition, polymorphisms in genes involved in the TLR (TLR1, TLR2, TLR4, TLR5, TLR9, and CD14) and NLR (NOD1, NOD2, NLRP3, NLRP12, NLRX1, CASP1, ASC, and CARD8) signaling pathways have been shown to modulate the risk of H. pylori infection, gastric precancerous lesions, and/or GC. Further, the modulation of PRRs has been suggested to suppress H. pylori-induced inflammation and enhance GC cell apoptosis, highlighting their potential relevance in GC therapeutics. In this review, we present current advances in our understanding of the role of the TLR and NLR signaling pathways in the pathogenesis of GC, address the involvement of other recently identified PRRs in GC, and discuss the potential implications of PRRs in GC immunotherapy.

  15. Pattern-Recognition Receptors and Gastric Cancer

    PubMed Central

    Castaño-Rodríguez, Natalia; Kaakoush, Nadeem O.; Mitchell, Hazel M.

    2014-01-01

    Chronic inflammation has been associated with an increased risk of several human malignancies, a classic example being gastric adenocarcinoma (GC). Development of GC is known to result from infection of the gastric mucosa by Helicobacter pylori, which initially induces acute inflammation and, in a subset of patients, progresses over time to chronic inflammation, gastric atrophy, intestinal metaplasia, dysplasia, and finally intestinal-type GC. Germ-line encoded receptors known as pattern-recognition receptors (PRRs) are critical for generating mature pro-inflammatory cytokines that are crucial for both Th1 and Th2 responses. Given that H. pylori is initially targeted by PRRs, it is conceivable that dysfunction within genes of this arm of the immune system could modulate the host response against H. pylori infection, and subsequently influence the emergence of GC. Current evidence suggests that Toll-like receptors (TLRs) (TLR2, TLR3, TLR4, TLR5, and TLR9), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) (NOD1, NOD2, and NLRP3), a C-type lectin receptor (DC-SIGN), and retinoic acid-inducible gene (RIG)-I-like receptors (RIG-I and MDA-5), are involved in both the recognition of H. pylori and gastric carcinogenesis. In addition, polymorphisms in genes involved in the TLR (TLR1, TLR2, TLR4, TLR5, TLR9, and CD14) and NLR (NOD1, NOD2, NLRP3, NLRP12, NLRX1, CASP1, ASC, and CARD8) signaling pathways have been shown to modulate the risk of H. pylori infection, gastric precancerous lesions, and/or GC. Further, the modulation of PRRs has been suggested to suppress H. pylori-induced inflammation and enhance GC cell apoptosis, highlighting their potential relevance in GC therapeutics. In this review, we present current advances in our understanding of the role of the TLR and NLR signaling pathways in the pathogenesis of GC, address the involvement of other recently identified PRRs in GC, and discuss the potential implications of PRRs in GC immunotherapy

  16. Lysophosphatidic acid stimulates thrombomodulin lectin-like domain shedding in human endothelial cells

    SciTech Connect

    Wu Hualin; Lin ChiIou; Huang Yuanli; Chen, Pin-Shern; Kuo, Cheng-Hsiang; Chen, Mei-Shing; Wu, G.C.-C.; Shi, G.-Y.; Yang, H.-Y.; Lee Hsinyu

    2008-02-29

    Thrombomodulin (TM) is an anticoagulant glycoprotein highly expressed on endothelial cell surfaces. Increased levels of soluble TM in circulation have been widely accepted as an indicator of endothelial damage or dysfunction. Previous studies indicated that various proinflammatory factors stimulate TM shedding in various cell types such as smooth muscle cells and epithelial cells. Lysophosphatidic acid (LPA) is a bioactive lipid mediator present in biological fluids during endothelial damage or injury. In the present study, we first observed that LPA triggered TM shedding in human umbilical vein endothelial cells (HUVECs). By Cyflow analysis, we showed that the LPA-induced accessibility of antibodies to the endothelial growth factor (EGF)-like domain of TM is independent of matrix metalloproteinases (MMPs), while LPA-induced TM lectin-like domain shedding is MMP-dependent. Furthermore, a stable cell line expressing TM without its lectin-like domain exhibited a higher cell proliferation rate than a stable cell line expressing full-length TM. These results imply that LPA induces TM lectin-like domain shedding, which might contribute to the exposure of its EGF-like domain for EGF receptor (EGFR) binding, thereby stimulating subsequent cell proliferation. Based on our findings, we propose a novel mechanism for the exposure of TM EGF-like domain, which possibly mediates LPA-induced EGFR transactivation.

  17. Glycodendritic structures based on Boltorn hyperbranched polymers and their interactions with Lens culinaris lectin.

    PubMed

    Arce, Eva; Nieto, Pedro M; Díaz, Vicente; Castro, Rossana García; Bernad, Antonio; Rojo, Javier

    2003-01-01

    Multivalent scaffolds bearing carbohydrates have been prepared to mediate biological processes where carbohydrates are involved. These systems consist of dendritic structures based on Boltorn H20 and H30 hyperbranched polymers to which carbohydrates are linked through a convenient spacer. Mannose has been chosen as a sugar unit to test the viability of this strategy. These glycodendritic compounds have been prepared in a few steps with good yields, showing a high solubility in physiological media and low toxicity. The binding of these dendritic polymers to the mannose-binding lectin Lens culinaris (LCA) was studied using STD-NMR experiments and quantitative precipitation assays. The results demonstrate the existence of a clear interaction between the mannose derivative systems and the Lens lectin where the dendritic scaffold does not have an important role in mannose binding but supplies the necessary multivalence for lectin cluster formation. These glycodendritic structures are able to interact with a receptor, and therefore they can be considered as promising tools for biological studies. PMID:12862436

  18. Development of the chick thymus microenvironment: a study by lectin histochemistry.

    PubMed Central

    Fernandez, J G; Sanchez, A J; Melcon, C; Chamorro, C A; Garcia, C; Paz, P

    1994-01-01

    The microenvironment of the chick thymus has been examined during development using lectin histochemistry. We have assayed WGA, Con A, RCA-I and TPA on thymic sections from 13, 15, 17 and 19 d chick embryos and 0, 5, 10 and 15 d chicks. All lectins were immunoperoxidase and colloidal gold-conjugated for transmission electron microscope observations. WGA labelled both the cortical and medullary thymic stroma at all the stages analysed. An intense reaction to WGA was observed in the subcortical region from stage 18 embryos to 5 d chicks. On the other hand, WGA did not stain medullary areas of the chick thymus. Con A lectin detected several cell clusters of stromal cells and thymocytes in cortical regions. These clusters could represent a lymphostromal complex with which Con A receptors are associated, probably in relation to cell adhesion. The residues detected by RCA were distributed both in stromal cells and thymocytes of the developing chick thymus. There was an increase of the reaction to RCA between the 19 d embryos and the 5 d chicks. This increase might be interpreted in terms of the secretion of thymic humoral factors at these stages. The thymic stromal cells stained with immunoperoxidase conjugated-TPA showed a reticular pattern in the medulla. There is a possibility that the fucosyl residues may be expressed in the Ia antigen as has previously been suggested in other species. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:7512541

  19. Glycodendritic structures based on Boltorn hyperbranched polymers and their interactions with Lens culinaris lectin.

    PubMed

    Arce, Eva; Nieto, Pedro M; Díaz, Vicente; Castro, Rossana García; Bernad, Antonio; Rojo, Javier

    2003-01-01

    Multivalent scaffolds bearing carbohydrates have been prepared to mediate biological processes where carbohydrates are involved. These systems consist of dendritic structures based on Boltorn H20 and H30 hyperbranched polymers to which carbohydrates are linked through a convenient spacer. Mannose has been chosen as a sugar unit to test the viability of this strategy. These glycodendritic compounds have been prepared in a few steps with good yields, showing a high solubility in physiological media and low toxicity. The binding of these dendritic polymers to the mannose-binding lectin Lens culinaris (LCA) was studied using STD-NMR experiments and quantitative precipitation assays. The results demonstrate the existence of a clear interaction between the mannose derivative systems and the Lens lectin where the dendritic scaffold does not have an important role in mannose binding but supplies the necessary multivalence for lectin cluster formation. These glycodendritic structures are able to interact with a receptor, and therefore they can be considered as promising tools for biological studies.

  20. High-level expression and characterization of a glycosylated human cementum protein 1 with lectin activity.

    PubMed

    Romo-Arévalo, Enrique; Arzate, Higinio; Montoya-Ayala, Gonzalo; Rodríguez-Romero, Adela

    2016-01-01

    This work aims to contribute to the knowledge of human cementum protein 1 (CEMP1), its conformational characteristics and influence during the biomineralization process. The results revealed that hrCEMP1 expressed in Pichia pastoris is a 2.4% glycosylated, thermostable protein which possesses a molecular mass of 28,770 Da. The circular dichroism spectrum indicated a secondary structure content of 28.6% of alpha-helix, 9.9% of beta-sheet and 61.5% of random-coil forms. Biological activity assays demonstrated that hrCEMP1 nucleates and regulates hydroxyapatite crystal growth. Hereby, it is demonstrated for the first time that CEMP1 has a (C-type) lectin-like activity and specifically recognizes mannopyranoside. The information produced by this biochemical and structural characterization may contribute to understand more fully the biological functions of CEMP1.

  1. Comparison of the antimicrobial adhesion potential of human body fluid glycoconjugates using fucose-binding lectin (PA-IIL) of Pseudomonas aeruginosa and Ulex europaeus lectin (UEA-I).

    PubMed

    Lerrer, Batia; Lesman-Movshovich, Efrat; Gilboa-Garber, Nechama

    2005-09-01

    Pseudomonas aeruginosa produces a fucose-binding lectin (PA-IIL) which strongly binds to human cells. This lectin was shown to be highly sensitive to inhibition by fucose-bearing human milk glycoproteins. Since the glycans of these glycoproteins mimic human cell receptors, they may function as decoys in blocking lectin-dependent pathogen adhesion to the host cells. Human saliva and seminal fluid also contain such compounds, and body fluids of individuals who are "secretors" express additional fucosylated (alpha 1,2) residues. The latter are selectively detected by Ulex europaeus lectin UEA-I. The aim of the present research was to compare the PA-IIL and UEA-I interactions with human salivas and seminal fluids of "secretors" and "nonsecretors" with those obtained with the respective milks. Using hemagglutination inhibition and Western blot analyses, we showed that PA-IIL interactions with the saliva and seminal fluid glycoproteins were somewhat weaker than those obtained with the milk and that "nonsecretor" body fluids were not less efficient than those of "secretors" in PA-IIL blocking. UEA-I, which interacted only with the "secretors" glycoproteins, was most sensitive to those of the seminal fluids.

  2. Biosynthesis of the Snowdrop (Galanthus nivalis) Lectin in Ripening Ovaries.

    PubMed

    Van Damme, E J; Peumans, W J

    1988-03-01

    The biosynthesis and processing of the Galanthus nivalis agglutinin were studied in vivo in ripening snowdrop ovaries. Using labeling and pulse chase labeling experiments it could be demonstrated that the snowdrop lectin is synthesized as a precursor of relative molecular weight (M(r)) 15,000 which is posttranslationally converted into the authentic lectin polypeptide of M(r) 13,000 with a half-life of about 6 hours. Gel filtration of an extract of [(3)H]leucine labeled ovaries on Sepharose 4B showed that a significant portion of the newly synthesized lectin is associated with the particulate fraction. When the organellar fraction was fractionated on isopycnic sucrose gradients this lectin banded in the same density region as the endoplasmic reticulum (ER) marker enzyme NADH cytochrome c reductase. Both radioactivity in lectin and in enzyme activity shifted towards a higher density in the presence of 2 millimolar Mg-acetate indicating that the labeled lectin was associated with the rough ER. Labeled lectin could be chased from the ER with a half-life of 4 hours and then accumulated in the soluble fraction. Whereas the ER-associated lectin contains exclusively polypeptides of M(r) 15,000 the soluble fraction contains both precursor molecules and mature lectin polypeptides. The snowdrop lectin in the ER is fully capable of binding immobilized mannose. It is associated into tetramers with an appropriate molecular weight of 60,000. These results indicate that newly synthesized snowdrop lectin is transiently associated with the ER before transport and processing.

  3. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides

    PubMed Central

    2015-01-01

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs. PMID:26407233

  4. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides.

    PubMed

    Mitchell, Daniel E; Gibson, Matthew I

    2015-10-12

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs. PMID:26407233

  5. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides.

    PubMed

    Mitchell, Daniel E; Gibson, Matthew I

    2015-10-12

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs.

  6. Lectins from opportunistic bacteria interact with acquired variable-region glycans of surface immunoglobulin in follicular lymphoma

    PubMed Central

    Schneider, Dunja; Dühren-von Minden, Marcus; Alkhatib, Alabbas; Setz, Corinna; van Bergen, Cornelis A. M.; Benkißer-Petersen, Marco; Wilhelm, Isabel; Villringer, Sarah; Krysov, Sergey; Packham, Graham; Zirlik, Katja; Römer, Winfried; Buske, Christian; Stevenson, Freda K.; Veelken, Hendrik

    2015-01-01

    B-cell antigen receptor (BCR) expression is a key feature of most B-cell lymphomas, but the mechanisms of BCR signal induction and the involvement of autoantigen recognition remain unclear. In follicular lymphoma (FL) B cells, BCR expression is retained despite a chromosomal translocation that links the antiapoptotic gene BCL2 to the regulatory elements of immunoglobulin genes, thereby disrupting 1 heavy-chain allele. A remarkable feature of FL-BCRs is the acquisition of potential N-glycosylation sites during somatic hypermutation. The introduced glycans carry mannose termini, which create potential novel binding sites for mannose-specific lectins. Here, we investigated the effect of N-linked variable-region glycosylation for BCR interaction with cognate antigen and with lectins of different origins. N-glycans were found to severely impair BCR specificity and affinity to the initial cognate antigen. In addition, we found that lectins from Pseudomonas aeruginosa and Burkholderia cenocepacia bind and stimulate FL cells. Human exposure to these bacteria can occur by contact with soil and water. In addition, they represent opportunistic pathogens in susceptible hosts. Understanding the role of bacterial lectins might elucidate the pathogenesis of FL and establish novel therapeutic approaches. PMID:25784678

  7. Molecular dynamics simulations of lectin domain of FimH and immunoinformatics for the design of potential vaccine candidates.

    PubMed

    Singaravelu, Muthukumar; Selvan, Anitha; Anishetty, Sharmila

    2014-10-01

    Adhesion of uropathogenic E. coli (UPEC) to uroepithelial cell receptors is facilitated through the lectin domain of FimH adhesin. In the current study, Molecular Dynamics (MD) simulations were performed for the lectin domain of FimH from UPEC J96. The high affinity state lectin domain was found to be stable and rigid during the simulations. Further, based on conserved subsequences around one of the disulfide forming cysteines, two sequence motifs were designed. An immunoinformatics approach was utilized to identify linear and discontinuous epitopes for the lectin domain of FimH. We propose that the accessibility of predicted epitopes should also be assessed in a dynamic aqueous environment to evaluate the potential of vaccine candidates. Since MD simulation data enables assessing the accessibility in a dynamic environment, we evaluated the accessibility of the top ranked discontinuous and linear epitopes using structures obtained at every nanosecond (ns) in the 1-20 ns MD simulation timeframe. Knowledge gained in this study has a potential utility in the design of vaccine candidates for Urinary Tract Infection (UTI).

  8. Dehydration of model membranes induced by lectins from Ricinus communis and Viscum album.

    PubMed Central

    Pohl, P; Saparov, S M; Pohl, E E; Evtodienko, V Y; Agapov, I I; Tonevitsky, A G

    1998-01-01

    The effects of ribosome-inactivating proteins (RIPs) from Ricinus communis and from Viscum album on the water permeability, Pf, and the surface dielectric constant, epsilon, of model membranes were studied. Pf was calculated from microelectrode measurements of the ion concentration distribution in the immediate vicinity of a planar membrane, and epsilon was obtained from the fluorescence of dansyl phosphatidylethanolamine incorporated into unilamellar vesicles. Pf and epsilon of fully saturated phosphatidylcholine membranes were affected only in the presence of a lectin receptor (monosialoganglioside, GM1) in the bilayer. It is suggested that the membrane area occupied by clustered lectin-receptor complexes is markedly less permeable to water. Protein binding to the receptor was not a prelude for hydrophobic lipid-protein interactions when the membranes were formed from a mixture of natural phospholipids with a high content of unsaturated fatty acids. These membranes, characterized by a high initial water permeability, were found to interact with the RIPs unspecifically. From a decrease of both Pf and epsilon it was concluded that not only water partitioning but also protein adsorption correlates with looser packing of polyunsaturated lipids at the lipid-water interface. PMID:9826608

  9. Role of Lectin-Like Oxidized Low Density Lipoprotein-1 in Fetoplacental Vascular Dysfunction in Preeclampsia

    PubMed Central

    Zuniga, Felipe A.; Ormazabal, Valeska; Gutierrez, Nicolas; Aguilera, Valeria; Radojkovic, Claudia; Veas, Carlos; Escudero, Carlos; Lamperti, Liliana; Aguayo, Claudio

    2014-01-01

    The bioavailability of nitric oxide (NO) represents a key marker in vascular health. A decrease in NO induces a pathological condition denominated endothelial dysfunction, syndrome observed in different pathologies, such as obesity, diabetes, kidney disease, cardiovascular disease, and preeclampsia (PE). PE is one of the major risks for maternal death and fetal loss. Recent studies suggest that the placenta of pregnant women with PE express high levels of lectin-like oxidized LDL receptor-1 (LOX-1), which induces endothelial dysfunction by increasing reactive oxygen species (ROS) and decreasing intracellular NO. Besides LOX-1 activation induces changes in migration and apoptosis of syncytiotrophoblast cells. However, the role of this receptor in placental tissue is still unknown. In this review we will describes the physiological roles of LOX-1 in normal placenta development and the potential involvement of this receptor in the pathophysiology of PE. PMID:25110674

  10. Molecular characterization of the reniform nematode C-type lectin gene family reveals a likely role in mitigating environmental stresses during plant parasitism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The reniform nematode, Rotylenchulus reniformis, is a damaging semi-endoparasitic pathogen of more than 300 plant species. As a sedentary obligate biotroph, R. reniformis must establish a complex feeding site within the root vasculature that functions as a continuous supply of nutrients. It was re...

  11. Galatrox is a C-type lectin in Bothrops atrox snake venom that selectively binds LacNAc-terminated glycans and can induce acute inflammation

    PubMed Central

    Sartim, Marco A; Riul, Thalita B; Del Cistia-Andrade, Camillo; Stowell, Sean R; Arthur, Connie M; Sorgi, Carlos A; Faccioli, Lucia H; Cummings, Richard D; Dias-Baruffi, Marcelo; Sampaio, Suely V

    2014-01-01

    Previous studies indicate that snake venom contains glycan-binding proteins (GBPs), although the binding specificity and biological activities of many of these GBPs is unclear. Here we report our studies on the glycan binding specificity and activities of galatrox, a Bothrops atrox snake venom-derived GBP. Glycan microarray analysis indicates that galatrox binds most strongly to glycans expressing N-acetyllactosamine (LacNAc), with a significant preference for Galβ1-4GlcNAcβ over Galβ1-3GlcNAcβ compounds. Galatrox also bound immobilized laminin, a LacNAc-dense extracellular matrix component, suggesting that this GBP can bind LacNAc-bearing glycoproteins. As several endogenous mammalian GBPs utilize a similar binding LacNAc binding preference to regulate neutrophil and monocyte activity, we hypothesized that galatrox may mediate B. atrox toxicity through regulation of leukocyte activity. Indeed, galatrox bound neutrophils and promoted leukocyte chemotaxis in a carbohydrate-dependent manner. Similarly, galatrox administration into the mouse peritoneal cavity induced significant neutrophil migration and the release of pro-inflammatory cytokines IL-1α and IL-6. Exposure of bone marrow-derived macrophages to galatrox induced generation of pro-inflammatory mediators IL-6, TNF-α, and keratinocyte-derived chemokine. This signaling by galatrox was mediated via its carbohydrate recognition domain by activation of the TLR4-mediated MyD88-dependent signaling pathway. These results indicate that galatrox has pro-inflammatory activity through its interaction with LacNAc-bearing glycans on neutrophils, macrophages and extracellular matrix proteins and induce the release of pro-inflammatory mediators. PMID:24973254

  12. Galatrox is a C-type lectin in Bothrops atrox snake venom that selectively binds LacNAc-terminated glycans and can induce acute inflammation.

    PubMed

    Sartim, Marco A; Riul, Thalita B; Del Cistia-Andrade, Camillo; Stowell, Sean R; Arthur, Connie M; Sorgi, Carlos A; Faccioli, Lucia H; Cummings, Richard D; Dias-Baruffi, Marcelo; Sampaio, Suely V

    2014-11-01

    Previous studies indicate that snake venom contains glycan-binding proteins (GBPs), although the binding specificity and biological activities of many of these GBPs is unclear. Here we report our studies on the glycan binding specificity and activities of galatrox, a Bothrops atrox snake venom-derived GBP. Glycan microarray analysis indicates that galatrox binds most strongly to glycans expressing N-acetyllactosamine (LacNAc), with a significant preference for Galβ1-4GlcNAcβ over Galβ1-3GlcNAcβ compounds. Galatrox also bound immobilized laminin, a LacNAc-dense extracellular matrix component, suggesting that this GBP can bind LacNAc-bearing glycoproteins. As several endogenous mammalian GBPs utilize a similar binding LacNAc binding preference to regulate neutrophil and monocyte activity, we hypothesized that galatrox may mediate B. atrox toxicity through regulation of leukocyte activity. Indeed, galatrox bound neutrophils and promoted leukocyte chemotaxis in a carbohydrate-dependent manner. Similarly, galatrox administration into the mouse peritoneal cavity induced significant neutrophil migration and the release of pro-inflammatory cytokines IL-1α and IL-6. Exposure of bone marrow-derived macrophages to galatrox induced generation of pro-inflammatory mediators IL-6, TNF-α, and keratinocyte-derived chemokine. This signaling by galatrox was mediated via its carbohydrate recognition domain by activation of the TLR4-mediated MyD88-dependent signaling pathway. These results indicate that galatrox has pro-inflammatory activity through its interaction with LacNAc-bearing glycans on neutrophils, macrophages and extracellular matrix proteins and induce the release of pro-inflammatory mediators. PMID:24973254

  13. The C-Type Lectin OCILRP2 Costimulates EL4 T Cell Activation via the DAP12-Raf-MAP Kinase Pathway

    PubMed Central

    Lou, Qiang; Zhang, Wei; Liu, Guangchao; Ma, Yuanfang

    2014-01-01

    OCILRP2 is a typical Type-II transmembrane protein that is selectively expressed in activated T lymphocytes, dendritic cells, and B cells and functions as a novel co-stimulator of T cell activation. However, the signaling pathways underlying OCILRP2 in T cell activation are still not completely understood. In this study, we found that the knockdown of OCILRP2 expression with shRNA or the blockage of its activity by an anti-OCILRP2 antagonist antibody reduced CD3/CD28-costimulated EL4 T cell viability and IL-2 production, inhibit Raf1, MAPK3, and MAPK8 activation, and impair NFAT and NF-κB transcriptional activities. Furthermore, immunoprecipitation results indicated that OCILRP2 could interact with the DAP12 protein, an adaptor containing an intracellular ITAM motif that can transduce signals to induce MAP kinase activation for T cell activation. Our data reveal that after binding with DAP12, OCILRP2 activates the Raf-MAP kinase pathways, resulting in T cell activation. PMID:25411776

  14. Agglucetin, a tetrameric C-type lectin-like venom protein, regulates endothelial cell survival and promotes angiogenesis by activating integrin {alpha}v{beta}3 signaling

    SciTech Connect

    Wang, W.-J.

    2008-05-02

    Agglucetin, a platelet glycoprotein (GP)Ib binding protein from Formosan Agkistrodon acutus (A. acutus) venom, could sustain human umbilical vein endothelial cell (HUVEC) proliferation and HUVEC adhering to immobilized agglucetin showed extensive spreading, which was strongly abrogated by integrin antagonists 7E3 and triflavin. Flow cytometric analyses confirmed the expression of GPIb complex on HUVEC is absent and fluorescein isothiocyanate (FITC)-agglucetin binds to HUVEC in a dose-dependent and saturable manner. Furthermore, native agglucetin specifically and dose-dependently inhibited the binding of FITC-23C6, an anti-{alpha}v{beta}3 monoclonal antibody (mAb), but not antibodies against {alpha}2 and {alpha}5, toward HUVEC and purified {alpha}v{beta}3 also bound to immobilized agglucetin-{beta} in a dose-dependent manner. Moreover, agglucetin exhibited a pro-angiogenic effect in vitro, as well as the focal adhesion kinase (FAK)-associated signaling molecules responsible for HUVEC activation were initiated by agglucetin. In conclusion, agglucetin, acting as a survival factor, promotes endothelial adhesion and angiogenesis by triggering {alpha}v{beta}3 signaling through FAK/phosphatidylinositol 3-kinase (PI3K)/Akt pathway.

  15. Effects of lectins with different carbohydrate-binding specificities on hepatoma, choriocarcinoma, melanoma and osteosarcoma cell lines.

    PubMed

    Wang, H; Ng, T B; Ooi, V E; Liu, W K

    2000-03-01

    The effects of lectins with different carbohydrate-binding specificities on human hepatoma (H3B), human choriocarcinoma (JAr), mouse melanoma (B16) and rat osteosarcoma (ROS) cell lines were investigated. Cell viability was estimated by uptake of crystal violet. Wheat germ lectin was the lectin with the most deleterious effect on the viability of H3B, JAr and ROS cell lines. The cytotoxicity of lectins with similar sugar-binding specificity to wheat germ lectin, including Maackia amurensis lectin and Solanum tuberosum lectin, was weaker than that of wheat germ lectin. N-acetylgalactosamine-and galactose-binding Tricholoma mongolicum lectin ranked third, after wheat germ lectin and Maackia amurensis lectin, with regard to its effect on H3B, and ranked, together with Maackia amurensis lectin, as the lectins with the second most pronounced effects on ROS. However, the cytotoxic effects of Tricholoma mongolicum lectin on JAr were much weaker than those of Maackia amurensis lectin, Solanum tuberosum lectin and Anguilla anguilla lectin. Artocarpus integrifolia lectin, Lens culinaris lectin and Anguilla anguilla lectin possessed milder cytotoxicity than the remaining lectins. which were approximately equipotent. The mannose-binding Narcissus pseudonarcissus and Lens culinaris lectins were only weakly cytotoxic, the exception being a stronger effect on H3B. The N-acetylgalactosamine-binding Glycine max lectin and methylgalactose-binding Artocarpus integrifolia lectin similarly exhibited low cytotoxicity. It can thus be concluded that in general the ranking was wheat germ lectin > Maackia amurensis lectin approximately Trichloma mongolicum lectins > other aforementioned lectins in cytotoxicity. A particular lectin may manifest more conspicuous toxicity on certain cell lines and less on others.

  16. Assessment of lectin inactivation by heat and digestion.

    PubMed

    Pusztai, A; Grant, G

    1998-01-01

    Proteins/glycoproteins from plants, particularly lectins, are more resistant to heat denaturation than animal proteins (1, 2). With legume seeds, whose lectin content is appreciable, this presents potentially serious problems in nutritional practice. Therefore, before they can be used safely, legume-based food/ feeds usually require thorough and expensive heat processing to inactivate antinutritive components. Indeed, dry or moist heating of seeds at 70°C for several h has little or no effect on their lectin activity (Fig. 1) and treatment at much higher temperatures is needed to inactivate the biological and antinutritional effects of legume lectins (1, 2). The safety aspect is even more serious with some monocot lectins, such as wheatgerm agglutinin or a number of oilseed lectins, such as peanut agglutinin and many others because they are extremely heat stable and normal cooking or other conventional heat treatments may fail to inactivate them (3) Thus, the best way to avoid potential harmful effects of these heat-resistant lectins is to limit their dietary intake to a minimum. Fig. 1. Loss of lectin activity during aqueous heat treatment of soybean at various temperatures. PMID:21374488

  17. Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential

    PubMed Central

    Gardères, Johan; Bourguet-Kondracki, Marie-Lise; Hamer, Bojan; Batel, Renato; Schröder, Heinz C.; Müller, Werner E. G.

    2015-01-01

    An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest. PMID:26262628

  18. Plant Lectins: Wheat Defense Strategy Against Hessian Fly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants produce a variety of defense proteins, including lectins in response to attack by phytophagous insects. Ultrastructural studies reveal that binding to insect gut structures and resistance to proteolytic degradation by insect digestive enzymes are the two main prerequisites for the lectins to...

  19. Combined biochemical and cytological analysis of membrane trafficking using lectins.

    PubMed

    Morgan, Gareth W; Kail, Mark; Hollinshead, Michael; Vaux, David J

    2013-10-01

    We have tested the application of high-mannose-binding lectins as analytical reagents to identify N-glycans in the early secretory pathway of HeLa cells during subcellular fractionation and cytochemistry. Post-endoplasmic reticulum (ER) pre-Golgi intermediates were separated from the ER on Nycodenz-sucrose gradients, and the glycan composition of each gradient fraction was profiled using lectin blotting. The fractions containing the post-ER pre-Golgi intermediates are found to contain a subset of N-linked α-mannose glycans that bind the lectins Galanthus nivalis agglutinin (GNA), Pisum sativum agglutinin (PSA), and Lens culinaris agglutinin (LCA) but not lectins binding Golgi-modified glycans. Cytochemical analysis demonstrates that high-mannose-containing glycoproteins are predominantly localized to the ER and the early secretory pathway. Indirect immunofluorescence microscopy revealed that GNA colocalizes with the ER marker protein disulfide isomerase (PDI) and the COPI coat protein β-COP. In situ competition with concanavalin A (ConA), another high-mannose specific lectin, and subsequent GNA lectin histochemistry refined the localization of N-glyans containing nonreducing mannosyl groups, accentuating the GNA vesicular staining. Using GNA and treatments that perturb ER-Golgi transport, we demonstrate that lectins can be used to detect changes in membrane trafficking pathways histochemically. Overall, we find that conjugated plant lectins are effective tools for combinatory biochemical and cytological analysis of membrane trafficking of glycoproteins.

  20. Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential.

    PubMed

    Gardères, Johan; Bourguet-Kondracki, Marie-Lise; Hamer, Bojan; Batel, Renato; Schröder, Heinz C; Müller, Werner E G

    2015-08-01

    An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest. PMID:26262628

  1. Interaction of native and asialo rat sublingual glycoproteins with lectins.

    PubMed

    Wu, A M; Herp, A; Song, S C; Wu, J H; Chang, K S

    1995-01-01

    The binding properties of the rat sublingual glycoprotein (RSL) and its asialo product with lectins were characterized by quantitative precipitin(QPA) and precipitin inhibition(QPIA) assays. Among twenty lectins tested for QPA, native RSL reacted well only with Artocarpus integrifolia (jacalin), but weakly or not at all with the other lectins. However, its asialo product (asialo-RSL) reacted strongly with many Gal and GalNAc specific lectins-it bound best to three of the GalNAc alpha 1-->Ser/Thr (Tn) and/or Gal beta 1-->4GlcNAc (II) active lectins [jacalin, Wistaria floribunda and Ricinus communis agglutinins] and completely precipitated each of these three lectins. Asialo-RSL also reacted well with Abrus precatorius, Glycine max, Bauhinia purpurea alba, and Maclura pomifera agglutinins, and abrin-a, but not with Arachis hypogeae and Dolichos biflorus agglutinins. The interaction between asialo-RSL and lectins were inhibited by either Gal beta 1-->4GlcNAc, p-NO2-phenyl alpha-GalNAc or both. The mapping of the precipitation and inhibition profiles leads to the conclusion that the asialo rat sublingual glycoprotein provides important ligands for II (Gal beta 1-->4GlcNAc beta 1-->) and Tn (GalNAc alpha 1-->Ser/Thr) active lectins.

  2. Biotoxicity assays for fruiting body lectins and other cytoplasmic proteins.

    PubMed

    Künzler, Markus; Bleuler-Martinez, Silvia; Butschi, Alex; Garbani, Mattia; Lüthy, Peter; Hengartner, Michael O; Aebi, Markus

    2010-01-01

    Recent studies suggest that a specific class of fungal lectins, commonly referred to as fruiting body lectins, play a role as effector molecules in the defense of fungi against predators and parasites. Hallmarks of these fungal lectins are their specific expression in reproductive structures, fruiting bodies, and/or sclerotia and their synthesis on free ribosomes in the cytoplasm. Fruiting body lectins are released upon damage of the fungal cell and bind to specific carbohydrate structures of predators and parasites, which leads to deterrence, inhibition of growth, and development or even killing of these organisms. Here, we describe assays to assess the toxicity of such lectins and other cytoplasmic proteins toward three different model organisms: the insect Aedes aegypti, the nematode Caenorhabditis elegans, and the amoeba Acanthamoeba castellanii. All three assays are based on heterologous expression of the examined proteins in the cytoplasm of Escherichia coli and feeding of these recombinant bacteria to omnivorous and bacterivorous organisms. PMID:20816208

  3. Mitogenic effect of Parkia speciosa seed lectin on human lymphocytes.

    PubMed

    Suvachittanont, W; Jaranchavanapet, P

    2000-12-01

    Mitogenic activity of a lectin, purified from Parkia speciosa seeds, on the isolated peripheral blood lymphocytes taken from normal blood donors and patients with esophageal carcinoma was examined using [3H]thymidine incorporation. The lectin increases the incorporation of [3H]thymidine into DNA of human lymphocytes. The activity of the lectin increased as its concentration was increased and then declined once the concentration passed an optimum point. The stimulant effect was also expressed using a proliferation index (PI): the ratio of [3H]thymidine incorporated into lymphocytes in the presence and absence of the lectin. The mitogenic activity of the lectin is comparable to those of the known T-cell mitogens, such as concanavalin A, phytohaemagglutinin, and pokeweed mitogen. Only slightly less responsiveness was observed in the case of lymphocytes from esophageal cancer compared to lymphocytes from normal donors. PMID:11199124

  4. Structure-function relationship of monocot mannose-binding lectins.

    PubMed Central

    Barre, A; Van Damme, E J; Peumans, W J; Rougé, P

    1996-01-01

    The monocot mannose-binding lectins are an extended superfamily of structurally and evolutionarily related proteins, which until now have been isolated from species of the Amaryllidaceae, Alliaceae, Araceae, Orchidaceae, and Liliaceae. To explain the obvious differences in biological activities, the structure-function relationships of the monocot mannose-binding lectins were studied by a combination of glycan-binding studies and molecular modeling using the deduced amino acid sequences of the currently known lectins. Molecular modeling indicated that the number of active mannose-binding sites per monomer varies between three and zero. Since the number of binding sites is fairly well correlated with the binding activity measured by surface plasmon resonance, and is also in good agreement with the results of previous studies of the biological activities of the mannose-binding lectins, molecular modeling is of great value for predicting which lectins are best suited for a particular application. PMID:8972598

  5. Nutritional evaluation of lectin-free soybeans for poultry.

    PubMed

    Douglas, M W; Parsons, C M; Hymowitz, T

    1999-01-01

    This study evaluated the nutritional value of raw lectin-free soybeans in comparison with raw Kunitz trypsin inhibitor-free soybeans, raw conventional soybeans, and commercial heat processed soybean meal (SBM). Analyzed lectin values (milligrams per kilogram) were 7.2, 7.1, and < 0.00015 for the Kunitz-free, conventional, and lectin-free soybeans, respectively. Three experiments were conducted using New Hampshire x Columbian male chicks fed 23% CP dextrose-soybean diets from 8 to 17 d of age. Growth performance of chicks fed lectin-free soybeans was greater (P < 0.05) than that of chicks fed raw conventional soybeans in all three experiments. However, performance of chicks fed lectin-free soybeans was lower than that of chicks fed Kunitz-free soybeans or SBM. The SBM yielded weight gains and feed efficiencies that were much higher than those observed from any of the raw soybeans. True amino acid digestibility and TMEn of the lectin-free and conventional soybeans were determined using the precision-fed cecectomized rooster assay. Seven roosters were crop-intubated with 30 g of soybeans and excreta were collected for 48 h. Digestibility coefficients of most amino acids for lectin-free soybeans were 5 to 8 percentage units higher than those for conventional soybeans, but the differences were not significant (P > 0.05). Likewise, the TMEn for lectin-free soybeans was 11% higher than that for raw conventional soybeans (3.577 vs 3.227 kcal/g DM) but the difference was not significant (P > 0.05). The results of this study indicate that the nutritional value of raw lectin-free soybeans is greater than raw conventional soybeans but is less than raw Kunitz-free soybeans and SBM, suggesting that trypsin inhibitor is a greater antinutritional factor than lectins. PMID:10023754

  6. Lectin activity in mycelial extracts of Fusarium species.

    PubMed

    Bhari, Ranjeeta; Kaur, Bhawanpreet; Singh, Ram S

    2016-01-01

    Lectins are non-immunogenic carbohydrate-recognizing proteins that bind to glycoproteins, glycolipids, or polysaccharides with high affinity and exhibit remarkable ability to agglutinate erythrocytes and other cells. In the present study, ten Fusarium species previously not explored for lectins were screened for the presence of lectin activity. Mycelial extracts of F. fujikuroi, F. beomiformii, F. begoniae, F. nisikadoi, F. anthophilum, F. incarnatum, and F. tabacinum manifested agglutination of rabbit erythrocytes. Neuraminidase treatment of rabbit erythrocytes increased lectin titers of F. nisikadoi and F. tabacinum extracts, whereas the protease treatment resulted in a significant decline in agglutination by most of the lectins. Results of hapten inhibition studies demonstrated unique carbohydrate specificity of Fusarium lectins toward O-acetyl sialic acids. Activity of the majority of Fusarium lectins exhibited binding affinity to d-ribose, l-fucose, d-glucose, l-arabinose, d-mannitol, d-galactosamine hydrochloride, d-galacturonic acid, N-acetyl-d-galactosamine, N-acetyl-neuraminic acid, 2-deoxy-d-ribose, fetuin, asialofetuin, and bovine submaxillary mucin. Melibiose and N-glycolyl neuraminic acid did not inhibit the activity of any of the Fusarium lectins. Mycelial extracts of F. begoniae, F. nisikadoi, F. anthophilum, and F. incarnatum interacted with most of the carbohydrates tested. F. fujikuroi and F. anthophilum extracts displayed strong interaction with starch. The expression of lectin activity as a function of culture age was investigated. Most species displayed lectin activity on the 7th day of cultivation, and it varied with progressing of culture age. PMID:27237111

  7. The Liverwort Contains a Lectin That Is Structurally and Evolutionary Related to the Monocot Mannose-Binding Lectins1

    PubMed Central

    Peumans, Willy J.; Barre, Annick; Bras, Julien; Rougé, Pierre; Proost, Paul; Van Damme, Els J.M.

    2002-01-01

    A mannose (Man)-binding lectin has been isolated and characterized from the thallus of the liverwort Marchantia polymorpha. N-terminal sequencing indicated that the M. polymorpha agglutinin (Marpola) shares sequence similarity with the superfamily of monocot Man-binding lectins. Searches in the databases yielded expressed sequence tags encoding Marpola. Sequence analysis, molecular modeling, and docking experiments revealed striking structural similarities between Marpola and the monocot Man-binding lectins. Activity and specificity studies further indicated that Marpola is a much stronger agglutinin than the Galanthus nivalis agglutinin and exhibits a preference for methylated Man and glucose, which is unprecedented within the family of monocot Man-binding lectins. The discovery of Marpola allows us, for the first time, to corroborate the evolutionary relationship between a lectin from a lower plant and a well-established lectin family from flowering plants. In addition, the identification of Marpola sheds a new light on the molecular evolution of the superfamily of monocot Man-binding lectins. Beside evolutionary considerations, the occurrence of a G. nivalis agglutinin homolog in a lower plant necessitates the rethinking of the physiological role of the whole family of monocot Man-binding lectins. PMID:12114560

  8. Mannose-based molecular patterns on stealth microspheres for receptor-specific targeting of human antigen-presenting cells.

    PubMed

    Wattendorf, Uta; Coullerez, Géraldine; Vörös, Janos; Textor, Marcus; Merkle, Hans P

    2008-10-21

    The targeting of antigen-presenting cells has recently gained strong attention for both targeted vaccine delivery and immunomodulation. We prepared surface-modified stealth microspheres that display various mannose-based ligands at graded ligand densities to target phagocytic C-type lectin receptors (CLRs) on human dendritic cells (DCs) and macrophages. Decoration of microspheres with carbohydrate ligands was achieved (i) by electrostatic surface assembly of mannan onto previously formed adlayers of poly( l-lysine) (PLL) or a mix of PLL and poly( l-lysine)- graft-poly(ethylene glycol) (PLL-PEG), or (ii) through assembly of PLL-PEG equipped with small substructure mannoside ligands, such as mono- and trimannose, as terminal substitution of the PEG chains. Microspheres carrying mannoside ligands were also studied in combination with an integrin-targeting RGD peptide ligand. Because of the presence of a mannan or PEG corona, such microspheres were protected against protein adsorption and opsonization, thus allowing the formation of specific ligand-receptor interactions. Mannoside density was the major factor for the phagocytosis of mannoside-decorated microspheres, although with limited efficiency. This strengthens the recent hypothesis by other authors that the mannose receptor (MR) only acts as a phagocytic receptor when in conjunction with yet unidentified partner receptor(s). Analysis of DC surface markers for maturation revealed that neither surface-assembled mannan nor mannoside-modified surfaces on the microspheres could stimulate DC maturation. Thus, phagocytosis upon recognition by CLRs alone cannot trigger DC activation toward a T helper response. The microparticulate platform established in this work represents a promising tool for systematic investigations of specific ligand-receptor interactions upon phagocytosis, including the screening for potential ligands and ligand combinations in the context of vaccine delivery and immunomodulation.

  9. Clec4A4 is a regulatory receptor for dendritic cells that impairs inflammation and T-cell immunity

    PubMed Central

    Uto, Tomofumi; Fukaya, Tomohiro; Takagi, Hideaki; Arimura, Keiichi; Nakamura, Takeshi; Kojima, Naoya; Malissen, Bernard; Sato, Katsuaki

    2016-01-01

    Dendritic cells (DCs) comprise several subsets that are critically involved in the initiation and regulation of immunity. Clec4A4/DC immunoreceptor 2 (DCIR2) is a C-type lectin receptor (CLR) exclusively expressed on CD8α− conventional DCs (cDCs). However, how Clec4A4 controls immune responses through regulation of the function of CD8α− cDCs remains unclear. Here we show that Clec4A4 is a regulatory receptor for the activation of CD8α− cDCs that impairs inflammation and T-cell immunity. Clec4a4−/−CD8α− cDCs show enhanced cytokine production and T-cell priming following Toll-like receptor (TLR)-mediated activation. Furthermore, Clec4a4−/− mice exhibit TLR-mediated hyperinflammation. On antigenic immunization, Clec4a4−/− mice show not only augmented T-cell responses but also progressive autoimmune pathogenesis. Conversely, Clec4a4−/− mice exhibit resistance to microbial infection, accompanied by enhanced T-cell responses against microbes. Thus, our findings highlight roles of Clec4A4 in regulation of the function of CD8α− cDCs for control of the magnitude and quality of immune response. PMID:27068492

  10. A C-type natriuretic peptide from the venom of the platypus (Ornithorhynchus anatinus): structure and pharmacology.

    PubMed

    de Plater, G M; Martin, R L; Milburn, P J

    1998-07-01

    A peptide which relaxes rat uterine smooth muscle and exhibits homology with the mammalian C-type natriuretic peptide (CNP) has previously been identified in platypus (Ornithorhynchus anatinus) venom from its partial N-terminal amino acid sequence. In this study we describe the purification, detailed structure, synthesis and pharmacological characteristics of this peptide, which has been designated ovCNP-39 (Ornithorhynchus venom C-type natriuretic peptide). Elucidation of the 39-residue amino acid sequence confirms the homology with mammalian CNPs. These peptides produce hypotension in vivo and relax smooth muscle in vitro, but are poorly characterised in terms of physiological function. ovCNP-39 is equipotent with human/rat/porcine CNP-22 in eliciting cyclic guanosine 5'-monophosphate (cGMP) elevation in cultured vascular smooth muscle cells, suggesting that, like CNP, it acts through the ANPB natriuretic peptide receptor subtype. The direct elevation of cGMP in vascular smooth muscle by ovCNP-39 may underlie the vasodilatory effects of platypus envenomation. PMID:9827022

  11. Radiolabeled Peptide Scaffolds for PET/SPECT - Optical in Vivo Imaging of Carbohydrate-Lectin Interactions

    SciTech Connect

    Deutscher, Susan

    2014-09-30

    The objective of this research is to develop phage display-selected peptides into radio- and fluoresecently- labeled scaffolds for the multimodal imaging of carbohydrate-lectin interactions. While numerous protein and receptor systems are being explored for the development of targeted imaging agents, the targeting and analysis of carbohydrate-lectin complexes in vivo remains relatively unexplored. Antibodies, nanoparticles, and peptides are being developed that target carbohydrate-lectin complexes in living systems. However, antibodies and nanoparticles often suffer from slow clearance and toxicity problems. Peptides are attractive alternative vehicles for the specific delivery of radionuclides or fluorophores to sites of interest in vivo, although, because of their size, uptake and retention may be less than antibodies. We have selected high affinity peptides that bind a specific carbohydrate-lectin complex involved in cell-cell adhesion and cross-linking using bacteriophage (phage) display technologies (1,2). These peptides have allowed us to probe the role of these antigens in cell adhesion. Fluorescent versions of the peptides have been developed for optical imaging and radiolabeled versions have been used in single photon emission computed tomography (SPECT) and positron emission tomography (PET) in vivo imaging (3-6). A benefit in employing the radiolabeled peptides in SPECT and PET is that these imaging modalities are widely used in living systems and offer deep tissue sensitivity. Radiolabeled peptides, however, often exhibit poor stability and high kidney uptake in vivo. Conversely, optical imaging is sensitive and offers good spatial resolution, but is not useful for deep tissue penetration and is semi-quantitative. Thus, multimodality imaging that relies on the strengths of both radio- and optical- imaging is a current focus for development of new in vivo imaging agents. We propose a novel means to improve the efficacy of radiolabeled and fluorescently

  12. CD44 Antibody Inhibition of Macrophage Phagocytosis Targets Fcγ Receptor- and Complement Receptor 3-Dependent Mechanisms.

    PubMed

    Amash, Alaa; Wang, Lin; Wang, Yawen; Bhakta, Varsha; Fairn, Gregory D; Hou, Ming; Peng, Jun; Sheffield, William P; Lazarus, Alan H

    2016-04-15

    Targeting CD44, a major leukocyte adhesion molecule, using specific Abs has been shown beneficial in several models of autoimmune and inflammatory diseases. The mechanisms contributing to the anti-inflammatory effects of CD44 Abs, however, remain poorly understood. Phagocytosis is a key component of immune system function and can play a pivotal role in autoimmune states where CD44 Abs have shown to be effective. In this study, we show that the well-known anti-inflammatory CD44 Ab IM7 can inhibit murine macrophage phagocytosis of RBCs. We assessed three selected macrophage phagocytic receptor systems: Fcγ receptors (FcγRs), complement receptor 3 (CR3), and dectin-1. Treatment of macrophages with IM7 resulted in significant inhibition of FcγR-mediated phagocytosis of IgG-opsonized RBCs. The inhibition of FcγR-mediated phagocytosis was at an early stage in the phagocytic process involving both inhibition of the binding of the target RBC to the macrophages and postbinding events. This CD44 Ab also inhibited CR3-mediated phagocytosis of C3bi-opsonized RBCs, but it did not affect the phagocytosis of zymosan particles, known to be mediated by the C-type lectin dectin-1. Other CD44 Abs known to have less broad anti-inflammatory activity, including KM114, KM81, and KM201, did not inhibit FcγR-mediated phagocytosis of RBCs. Taken together, these findings demonstrate selective inhibition of FcγR and CR3-mediated phagocytosis by IM7 and suggest that this broadly anti-inflammatory CD44 Ab inhibits these selected macrophage phagocytic pathways. The understanding of the immune-regulatory effects of CD44 Abs is important in the development and optimization of therapeutic strategies for the potential treatment of autoimmune conditions.

  13. CD44 Antibody Inhibition of Macrophage Phagocytosis Targets Fcγ Receptor- and Complement Receptor 3-Dependent Mechanisms.

    PubMed

    Amash, Alaa; Wang, Lin; Wang, Yawen; Bhakta, Varsha; Fairn, Gregory D; Hou, Ming; Peng, Jun; Sheffield, William P; Lazarus, Alan H

    2016-04-15

    Targeting CD44, a major leukocyte adhesion molecule, using specific Abs has been shown beneficial in several models of autoimmune and inflammatory diseases. The mechanisms contributing to the anti-inflammatory effects of CD44 Abs, however, remain poorly understood. Phagocytosis is a key component of immune system function and can play a pivotal role in autoimmune states where CD44 Abs have shown to be effective. In this study, we show that the well-known anti-inflammatory CD44 Ab IM7 can inhibit murine macrophage phagocytosis of RBCs. We assessed three selected macrophage phagocytic receptor systems: Fcγ receptors (FcγRs), complement receptor 3 (CR3), and dectin-1. Treatment of macrophages with IM7 resulted in significant inhibition of FcγR-mediated phagocytosis of IgG-opsonized RBCs. The inhibition of FcγR-mediated phagocytosis was at an early stage in the phagocytic process involving both inhibition of the binding of the target RBC to the macrophages and postbinding events. This CD44 Ab also inhibited CR3-mediated phagocytosis of C3bi-opsonized RBCs, but it did not affect the phagocytosis of zymosan particles, known to be mediated by the C-type lectin dectin-1. Other CD44 Abs known to have less broad anti-inflammatory activity, including KM114, KM81, and KM201, did not inhibit FcγR-mediated phagocytosis of RBCs. Taken together, these findings demonstrate selective inhibition of FcγR and CR3-mediated phagocytosis by IM7 and suggest that this broadly anti-inflammatory CD44 Ab inhibits these selected macrophage phagocytic pathways. The understanding of the immune-regulatory effects of CD44 Abs is important in the development and optimization of therapeutic strategies for the potential treatment of autoimmune conditions. PMID:26944929

  14. Cloning and characterization of root-specific barley lectin

    SciTech Connect

    Lerner, D.R.; Raikhel, N.V. )

    1989-09-01

    Cereal lectins are a class of biochemically and antigenically related proteins localized in a tissue-specific manner in embryos and adult plants. To study the specificity of lectin expression, a barley (Hordeum vulgare L.) embryo cDNa library was constructed and a clone (BLc3) for barley lectin was isolated. BLc3 is 972 nucleotides long and includes an open reading frame of 212 amino acids. The deduced amino acid sequence contains a putative signal peptide of 26 amino acid residues followed by a 186 amino acid polypeptide. This polypeptide has 95% sequence identity to the antigenically indistinguishable wheat germ agglutinin isolectin-B (WGA-B) suggesting that BLc3 encodes barley lectin. Further evidence that BLc3 encodes barley lectin was obtained by immunoprecipitation of the in vitro translation products of BLc3 RNA transcripts and barley embryo poly(A{sup +}) RNA. In situ hybridizations with BLc3 showed that barley lectin gene expression is confined to the outermost cell layers of both embryonic and adult root tips. On Northern blots, BLc3 hybridizes to a 1.0 kilobyte mRNA in poly(A{sup +}) RNA from both embryos and root tips. We suggest, on the basis of immunoblot experiments, that barley lectin is synthesized as a glycosylated precursor and processed by removal of a portion of the carboxyl terminus including the single N-linked glycosylation site.

  15. Potential immunomodulatory effects of plant lectins in Schistosoma mansoni infection.

    PubMed

    Reis, Eliana A G; Athanazio, Daniel A; Cavada, Benildo Sousa; Teixeira, Edson Holanda; de Paulo Teixeira Pinto, Vicente; Carmo, Theomira M A; Reis, Alice; Trocolli, Graziela; Croda, Julio; Harn, Donald; Barral-Netto, Manoel; Reis, Mitermayer G

    2008-01-01

    Lectins are sugar-binding glycoproteins that can stimulate, in a non-antigen-specific fashion, lymphocytes, leading to proliferation and cytokine production. Some lectins are utilized as in vitro mitogenic lymphocyte stimulators and their use as immunomodulators against infectious diseases has been evaluated experimentally. In the experimental murine model, the immune response to schistosomiasis is Th1-like during the initial stage of infection, with a shift towards a Th2-like response after oviposition. We report the response of schistosomiasis patients' (n=37) peripheral blood mononuclear cells (PBMC) to stimulation by lectins, including newly isolated lectins from Brazilian flora, and by Schistosomamansoni soluble egg antigens (SEA). Cytokine production upon lectin stimulation ex vivo was assessed in PBMC supernatants, collected at 24 and 72 h, by sandwich ELISA to IL-5, IL-10, TNF-alpha and IFN-gamma. In PBMC from infected patients all but one of the lectins induced a Th2-like cytokine response, characterized by elevated IL-5 production that was higher than that induced by SEA stimulation alone. Our results show that the Th2 environment present during schistosomiasis is not affected and that it may be further stimulated by the presence of lectins. PMID:18579103

  16. Isolation and characterization of a lectin from Japanese mottled beans.

    PubMed

    Zhao, Yuan; Ahmad, Ameer Maqsood; Cheung, Randy Chi Fai; Ng, Tzi Bun

    2014-07-01

    A 64-kDa dimeric lectin was purified from Phaseolus vulgaris cv. Japanese mottled beans. The purification protocol involved ion exchange chromatography with Q-Sepharose and SP-Sepharose and size exclusion chromatography on Superdex 75. The lectin was adsorbed on both Q-Sepharose and SP-Sepharose columns. Finally, the lectin gave a sharp absorbance peak which corresponded to 64 kDa based on results of size exclusion chromatography. Sodium dodecyl sulphate- polyacrylamide gel electrophoresis displayed a single band at around 32 kDa, indicating that the protein was dimeric. The hemagglutination inhibition assay indicated that the lectin showed specificity toward galactose. The lectin preserved hemagglutinating activity below 70 °C and at a pH range 3 - 12. The lectin was able to inhibit proliferation of MCF-7 cells and Hep G2 cells and possessed antifungal activity toward Mycosphaeralla arachidicola with an IC50 value of 3.9 µM. The activity of HIV-1 reverse transcriptase was reduced by 61.9 % in the presence of the lectin at 6.25 µM concentration. PMID:24654854

  17. New sensitive detection method for lectin hemagglutination using microscopy.

    PubMed

    Adamová, Lenka; Malinovská, Lenka; Wimmerová, Michaela

    2014-10-01

    The blood group system AB0 is determined by the composition of terminal oligosaccharides on red blood cells. Thanks to this structural feature, these groups can be recognized by saccharide-recognizing compounds. Lectins are proteins that are able to reversibly bind saccharide structures. They generally occur as multimers and are known as hemagglutination agents. Hemagglutination is a process in which blood cells are cross-linked via multivalent molecules. Apart from lectins, hemagglutination can also be caused by antibodies or viruses. A hemagglutination assay is commonly used for the detection of multivalent molecules that recognize blood cells, in order to search for their sugar specificity. It is traditionally performed on a microtiter plate, where the lectin solution is serially diluted and the lowest concentration of lectin causing agglutination is detected. This experimental set-up is utilized further for testing lectin specificity via a hemagglutination inhibition assay. We have developed a new way of detecting hemagglutination using microscopy, which was tested on purified lectins as well as cell lysates. Hemagglutination was performed on a microscope slide directly and detected using a microscope. Comparison with the standard hemagglutination assay using microtiter plates revealed that microscopic approach is faster and more robust and allows fast determination of lectin activities immediately in bacterial cytosols.

  18. Intrinsic fluorescence studies on saccharide binding to Artocarpus integrifolia lectin.

    PubMed

    Sastry, M V; Surolia, A

    1986-10-01

    The combining region of Artocarpus integrifolia lectin has been studied by using the ligand-induced changes in the fluorescence of the lectin. The saccharide binding properties of the lectin show that C-1, C-2, C-4, and C-6 hydroxyl groups of D-galactose are important loci for sugar binding. The alpha-anomer of galactose binds more strongly than its beta-counterpart. Inversion in the configuration at C-4 as in glucose results in a loss of binding to the lectin. The C-6 hydroxyl group is also presumably involved in binding as D-fucose does not bind to the lectin. The lectin binds to the Thomsen-Friedenreich antigen (Gal beta(1----3)GalNAc) more strongly than the other disaccharides studied, viz. Gal beta (1----4) Gal and Gal beta (1----3) GlcNAc, which are topographically similar to T-antigen. This observation suggests that the combining region of Artocarpus lectin is complementary to that of T-antigen. Solvent accessibility of the protein fluorophores have been probed by the quenching of protein fluorescence by Iodide ion in the absence and presence of sugar. In the presence of sugar a slight inaccessibility of the fluorophores to the solvent has been observed.

  19. C-Type Natriuretic Peptide Induces Anti-contractile Effect Dependent on Nitric Oxide, Oxidative Stress, and NPR-B Activation in Sepsis

    PubMed Central

    Pernomian, Laena; Prado, Alejandro F.; Silva, Bruno R.; Azevedo, Aline; Pinheiro, Lucas C.; Tanus-Santos, José E.; Bendhack, Lusiane M.

    2016-01-01

    Aims: To evaluate the role of nitric oxide, reactive oxygen species (ROS), and natriuretic peptide receptor-B activation in C-type natriuretic peptide-anti-contractile effect on Phenylephrine-induced contraction in aorta isolated from septic rats. Methods and Results: Cecal ligation and puncture (CLP) surgery was used to induce sepsis in male rats. Vascular reactivity was conducted in rat aorta and resistance mesenteric artery (RMA). Measurement of survival rate, mean arterial pressure (MAP), plasma nitric oxide, specific protein expression, and localization were evaluated. Septic rats had a survival rate about 37% at 4 h after the surgery, and these rats presented hypotension compared to control-operated (Sham) rats. Phenylephrine-induced contraction was decreased in sepsis. C-type natriuretic peptide (CNP) induced anti-contractile effect in aortas. Plasma nitric oxide was increased in sepsis. Nitric oxide-synthase but not natriuretic peptide receptor-B expression was increased in septic rat aortas. C-type natriuretic peptide-anti-contractile effect was dependent on nitric oxide-synthase, ROS, and natriuretic peptide receptor-B activation. Natriuretic peptide receptor-C, protein kinase-Cα mRNA, and basal nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ROS production were lower in septic rats. Phenylephrine and CNP enhanced ROS production. However, stimulated ROS production was low in sepsis. Conclusion: CNP induced anti-contractile effect on Phenylephrine contraction in aortas from Sham and septic rats that was dependent on nitric oxide-synthase, ROS, and natriuretic peptide receptor-B activation. PMID:27445832

  20. Effects of lectin ingestion on animal growth and internal organs.

    PubMed

    Pusztai, A

    1998-01-01

    Lectins are essential and omnipresent plant constituents. As many foods are of plant origin, the daily ingestion of lectins by both humans and animals is appreciable. For example, in an ad hoc survey, 53 edible plants were shown to contain lectins and approx 30% of fresh and processed food regularly consumed by humans had significant hemagglutinating activity (1). The situation is potentially even more acute in animal nutrition because animal diet is less diverse than that of humans, and in most instances foodstuffs are not thoroughly heat-treated. This is particularly significant in the light of our finding a correlation between lectin activity and antinutritional effects (2). As in evolution, the mammalian gut has been regularly exposed to lectins, they must have played an important part in the development of the digestive system. Although based on experience, most overtly toxic plants have been eliminated from the diet, many plants with appreciable lectin content are still consumed because it has not been easy to relate growth retardation and antinutritional, mild allergic or other subclinical symptoms to the food consumed or a particular component of it. As some lectins are at least partially heat stable and most survive the passage through the gut in functionally and immunologically intact form, their interaction with the gut surface epithelium (3) can damage the gut at high dietary intakes and this may lead to digestive disorders/diseases in some instances. However, it is not generally appreciated that not all lectins are antinutrients and indeed some may have beneficial effects and be of potential value in nutritional practice. Accordingly, it is of considerable importance to establish whether a lectin has deleterious or potentially beneficial effects for mammals. Unfortunately at present there are no adequate in vitro methods to do this reliably and it is usually necessary to carry out in vivo animal feeding studies, despite their relatively cumbersome

  1. In vivo biosynthetic studies of the Dolichos biflorus seed lectin

    SciTech Connect

    Quinn, J.M.; Etzler, M.E. )

    1989-12-01

    The in vivo biosynthesis of the Dolichos biflorus seed lectin was studied by pulse-chase labeling experiments using ({sup 35}S)methionine and ({sup 14}C)glucosamine. These studies demonstrate that each of the two mature lectin subunit types are derived by the processing of separate glycosylated precursors. The appearance of the precursor to subunit I before the precursor to subunit II supports the possibility raised by previous studies that both subunit types of this lectin may originate from a single gene product.

  2. The gene for stinging nettle lectin (Urtica dioica agglutinin) encodes both a lectin and a chitinase.

    PubMed

    Lerner, D R; Raikhel, N V

    1992-06-01

    Chitin-binding proteins are present in a wide range of plant species, including both monocots and dicots, even though these plants contain no chitin. To investigate the relationship between in vitro antifungal and insecticidal activities of chitin-binding proteins and their unknown endogenous functions, the stinging nettle lectin (Urtica dioica agglutinin, UDA) cDNA was cloned using a synthetic gene as the probe. The nettle lectin cDNA clone contained an open reading frame encoding 374 amino acids. Analysis of the deduced amino acid sequence revealed a 21-amino acid putative signal sequence and the 86 amino acids encoding the two chitin-binding domains of nettle lectin. These domains were fused to a 19-amino acid "spacer" domain and a 244-amino acid carboxyl extension with partial identity to a chitinase catalytic domain. The authenticity of the cDNA clone was confirmed by deduced amino acid sequence identity with sequence data obtained from tryptic digests, RNA gel blot, and polymerase chain reaction analyses. RNA gel blot analysis also showed the nettle lectin message was present primarily in rhizomes and inflorescence (with immature seeds) but not in leaves or stems. Chitinase enzymatic activity was found when the chitinase-like domain alone or the chitinase-like domain with the chitin-binding domains were expressed in Escherichia coli. This is the first example of a chitin-binding protein with both a duplication of the 43-amino acid chitin-binding domain and a fusion of the chitin-binding domains to a structurally unrelated domain, the chitinase domain. PMID:1375935

  3. Impacts of Shewanella oneidensis c-type cytochromes on aerobic and anaerobic respiration.

    PubMed

    Gao, Haichun; Barua, Soumitra; Liang, Yili; Wu, Lin; Dong, Yangyang; Reed, Samantha; Chen, Jingrong; Culley, Dave; Kennedy, David; Yang, Yunfeng; He, Zhili; Nealson, Kenneth H; Fredrickson, James K; Tiedje, James M; Romine, Margaret; Zhou, Jizhong

    2010-07-01

    Shewanella are renowned for their ability to utilize a wide range of electron acceptors (EA) for respiration, which has been partially accredited to the presence of a large number of the c-type cytochromes. To investigate the involvement of c-type cytochrome proteins in aerobic and anaerobic respiration of Shewanella oneidensis Mr -1, 36 in-frame deletion mutants, among possible 41 predicted, c-type cytochrome genes were obtained. The potential involvement of each individual c-type cytochrome in the reduction of a variety of EAs was assessed individually as well as in competition experiments. While results on the well-studied c-type cytochromes CymA(SO4591) and MtrC(SO1778) were consistent with previous findings, collective observations were very interesting: the responses of S. oneidensis Mr -1 to low and highly toxic metals appeared to be significantly different; CcoO, CcoP and PetC, proteins involved in aerobic respiration in various organisms, played critical roles in both aerobic and anaerobic respiration with highly toxic metals as EA. In addition, these studies also suggested that an uncharacterized c-type cytochrome (SO4047) may be important to both aerobiosis and anaerobiosis.

  4. Impacts of Shewanella oneidensis c-type cytochromes on aerobic and anaerobic respiration

    SciTech Connect

    Gao, Haichun; Barua, Soumitra; Liang, Yili; Wu, Lianming; Dong, Yangyang; Reed, Samantha B.; Chen, Jingrong; Culley, David E.; Kennedy, David W.; Yang, Yunfeng; He, Zhili; Nealson, Kenneth H.; Fredrickson, Jim K.; Tiedje, James M.; Romine, Margaret F.; Zhou, Jizhong

    2010-06-24

    Shewanella are renowned for their ability to utilize a wide range of electron acceptors (EA) for respiration, which has been partially accredited to the presence of a large number of the c-type cytochromes. To investigate the involvement of c-type cytochrome proteins in aerobic and anaerobic respiration of Shewanella oneidensis Mr -1, 36 in-frame deletion mutants, among possible 41 predicted, c-type cytochrome genes were obtained. The potential involvement of each individual c-type cytochrome in the reduction of a variety of EAs was assessed individually as well as in competition experiments. While results on the wellstudied c-type cytochromes CymA(SO4591) and MtrC(SO1778) were consistent with previous findings, collective observations were very interesting: the responses of S. oneidensis Mr -1 to low and highly toxic metals appeared to be significantly different; CcoO, CcoP and PetC, proteins involved in aerobic respiration in various organisms, played critical roles in both aerobic and anaerobic respiration with highly toxic metals as EA. In addition, these studies also suggested that an uncharacterized c-type cytochrome (SO4047) may be important to both aerobiosis and anaerobiosis.

  5. Opsonin-independent ligation of Fc gamma receptors. The 3G8-bearing receptors on neutrophils mediate the phagocytosis of concanavalin A- treated erythrocytes and nonopsonized Escherichia coli

    PubMed Central

    1987-01-01

    We report that phagocytosis by human neutrophils of Con A-treated erythrocytes (E-Con A) and nonopsonized Escherichia coli with mannose- binding adhesions is mediated by the Fc gamma receptor bearing the 3G8 epitope. Modulation of Fc receptors by pretreating with aggregated-IgG or with 3G8 anti-Fc gamma receptor mAb markedly inhibited internalization of E-Con A and E. coli without altering their cell surface attachment. Phagocytosis of these probes was specifically blocked by alpha-methylmannoside and D-mannose and not by other monosaccharides. Thus, recognition of E-Con A and E. coli by the Fc receptor is dependent upon the mannose-specific interaction with lectin or lectin-like adhesions. These data demonstrate that ligands other than the classical IgG opsonins can bind to classical immune receptors for IgG through lectin-carbohydrate interactions. PMID:2445895

  6. Fine specificities of two lectins from Cymbosema roseum seeds: a lectin specific for high-mannose oligosaccharides and a lectin specific for blood group H type II trisaccharide.

    PubMed

    Dam, Tarun K; Cavada, Benildo S; Nagano, Celso S; Rocha, Bruno Am; Benevides, Raquel G; Nascimento, Kyria S; de Sousa, Luiz Ag; Oscarson, Stefan; Brewer, C Fred

    2011-07-01

    The legume species of Cymbosema roseum of Diocleinae subtribe produce at least two different seed lectins. The present study demonstrates that C. roseum lectin I (CRL I) binds with high affinity to the "core" trimannoside of N-linked oligosaccharides. Cymbosema roseum lectin II (CRL II), on the other hand, binds with high affinity to the blood group H trisaccharide (Fucα1,2Galα1-4GlcNAc-). Thermodynamic and hemagglutination inhibition studies reveal the fine binding specificities of the two lectins. Data obtained with a complete set of monodeoxy analogs of the core trimannoside indicate that CRL I recognizes the 3-, 4- and 6-hydroxyl groups of the α(1,6) Man residue, the 3- and 4-hydroxyl group of the α(1,3) Man residue and the 2- and 4-hydroxyl groups of the central Man residue of the trimannoside. CRL I possesses enhanced affinities for the Man5 oligomannose glycan and a biantennary complex glycan as well as glycoproteins containing high-mannose glycans. On the other hand, CRL II distinguishes the blood group H type II epitope from the Lewis(x), Lewis(y), Lewis(a) and Lewis(b) epitopes. CRL II also distinguishes between blood group H type II and type I trisaccharides. CRL I and CRL II, respectively, possess differences in fine specificities when compared with other reported mannose and fucose recognizing lectins. This is the first report of a mannose-specific lectin (CRL I) and a blood group H type II-specific lectin (CRL II) from seeds of a member of the Diocleinae subtribe.

  7. Structure and Function of Mammalian Carbohydrate-Lectin Interactions

    NASA Astrophysics Data System (ADS)

    Anderson, Kevin; Evers, David; Rice, Kevin G.

    Over the past three decades the field of glycobiology has expanded beyond a basic understanding of the structure and biosynthesis of glycoprotein, proteoglycans, and glycolipids toward a more detailed picture of how these molecules afford communication through binding to mammalian lectins. Although the number of different mammalian lectin domains appears to be finite and even much smaller than early estimates predicated based on the diversity of glycan structures, nature appears capable of using these in numerous combinations to fine tune specificity. The following provides an overview of the major classes of mammalian lectins and discusses their glycan binding specificity. The review provides a snapshot of the field of glycobiology that continues to grow providing an increasing number of examples of biological processes that rely upon glycan-lectin binding.

  8. An alternate high yielding purification method for Clitoria ternatea lectin.

    PubMed

    Naeem, Aabgeena; Ahmad, Ejaz; Khan, Rizwan Hasan

    2007-10-01

    In our previous publication we had reported the purification and characterization of Clitoria ternatea agglutinin from its seeds on fetuin CL agarose affinity column, designated CTA [A. Naeem, S. Haque, R.H. Khan. Protein J., 2007]. Since CTA binds beta-d-galactosides, this lectin can be used as valuable tool for glycobiology studies in biomedical and cancer research. So an attempt was made for a high yielding alternative purification method employing the use of asialofetuin CL agarose column for the above-mentioned lectin, designated CTL. The fetuin affinity purified agglutinin was found similar to asialofetuin affinity purified lectin in SDS pattern, HPLC and N-terminal sequence. The content of lectin was found to be 30mg/30g dry weight of pulse. The yield was 2.8% as compared to 0.3% obtained on fetuin column. The number of tryptophan and tyrosine estimated was four and six per subunit. PMID:17590430

  9. Isolation and characterization of a lectin from Annona muricata seeds.

    PubMed

    Damico, D C S; Freire, M G M; Gomes, V M; Toyama, M H; Marangoni, S; Novello, J C; Macedo, M L R

    2003-11-01

    A lectin with a high affinity for glucose/mannose was isolated from Annona muricata seeds (Annonaceae) by gel filtration chromatography on Sephacryl S-200, ion exchange chromatography on a DEAE SP-5 PW column, and molecular exclusion on a Protein Pak Glass 300 SW column. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (PAGE) yielded two protein bands of approximately 14 kDa and 22 kDa. However, only one band was seen in native PAGE. The Mr of the lectin estimated by fast-performance liquid chromatography-gel filtration on Superdex 75 was 22 kDa. The lectin was a glycoprotein with 8% carbohydrate (neutral sugar) and required divalent metal cations (Ca2+, Mg2+, and Mn2+) for full activity. Amino acid analysis revealed a large content of Glx, Gly, Phe, and Lys. The lectin agglutinated dog, chicken, horse, goose, and human erythrocytes and inhibited the growth of the fungi Fusarium oxysporum, Fusarium solani, and Colletotrichum musae.

  10. Insights into animal and plant lectins with antimicrobial activities.

    PubMed

    Dias, Renata de Oliveira; Machado, Leandro Dos Santos; Migliolo, Ludovico; Franco, Octavio Luiz

    2015-01-05

    Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs.

  11. Lectins stain cells differentially in the coral, Montipora capitata

    USGS Publications Warehouse

    Work, Thierry M.; Farah, Yael

    2014-01-01

    A limitation in our understanding of coral disease pathology and cellular pathogenesis is a lack of reagents to characterize coral cells. We evaluated the utility of plant lectins to stain tissues of a dominant coral, Montipora capitata, from Hawaii. Of 22 lectins evaluated, nine of these stained structures in the upper or basal body wall of corals. Specific structures revealed by lectins that were not considered distinct or evident on routine hematoxylin and eosin sections of coral tissues included apical and basal granules in gastrodermis and epidermis, cnidoglandular tract and actinopharynx cell surface membranes, capsules of mature holotrichous isorhizas, and perivitelline and periseminal cells. Plant lectins could prove useful to further our understanding of coral physiology, anatomy, cell biology, and disease pathogenesis.

  12. Protozoa lectins and their role in host-pathogen interactions.

    PubMed

    Singh, Ram Sarup; Walia, Amandeep Kaur; Kanwar, Jagat Rakesh

    2016-01-01

    Lectins are proteins/glycoproteins of non-immune origin that agglutinate red blood cells, lymphocytes, fibroblasts, etc., and bind reversibly to carbohydrates present on the apposing cells. They have at least two carbohydrate binding sites and their binding can be inhibited by one or more carbohydrates. Owing to carbohydrate binding specificity of lectins, they mediate cell-cell interactions and play role in protozoan adhesion and host cell cytotoxicity, thus are central to the pathogenic property of the parasite. Several parasitic protozoa possess lectins which mediate parasite adherence to host cells based on their carbohydrate specificities. These interactions could be exploited for development of novel therapeutics, targeting the adherence and thus helpful in eradicating wide spread of protozoan diseases. The current review highlights the present state knowledge with regard to protozoal lectins with an emphasis on their haemagglutination activity, carbohydrate specificity, characteristics and also their role in pathogenesis notably as adhesion molecules, thereby aiding the pathogen in disease establishment.

  13. Lectins stain cells differentially in the coral, Montipora capitata.

    PubMed

    Work, Thierry M; Farah, Yael

    2014-03-01

    A limitation in our understanding of coral disease pathology and cellular pathogenesis is a lack of reagents to characterize coral cells. We evaluated the utility of plant lectins to stain tissues of a dominant coral, Montipora capitata, from Hawaii. Of 22 lectins evaluated, nine of these stained structures in the upper or basal body wall of corals. Specific structures revealed by lectins that were not considered distinct or evident on routine hematoxylin and eosin sections of coral tissues included apical and basal granules in gastrodermis and epidermis, cnidoglandular tract and actinopharynx cell surface membranes, capsules of mature holotrichous isorhizas, and perivitelline and periseminal cells. Plant lectins could prove useful to further our understanding of coral physiology, anatomy, cell biology, and disease pathogenesis. PMID:24518620

  14. Potential of KM+ lectin in immunization against Leishmania amazonensis infection.

    PubMed

    Teixeira, Clarissa R; Cavassani, Karen A; Gomes, Regis B; Teixeira, Maria Jania; Roque-Barreira, Maria-Cristina; Cavada, Benildo S; da Silva, João Santana; Barral, Aldina; Barral-Netto, Manoel

    2006-04-01

    In the present study we evaluated Canavalia brasiliensis (ConBr), Pisum arvense (PAA) and Artocarpus integrifolia (KM+) lectins as immunostimulatory molecules in vaccination against Leishmania amazonensis infection. Although they induced IFN-gamma production, the combination of the lectins with SLA antigen did not lead to lesion reduction. However, parasite load was largely reduced in mice immunized with KM+ lectin and SLA. KM+ induced a smaller inflammatory reaction in the air pouch model and was able to inhibit differentiation of dendritic cells (BMDC), but to induce maturation by enhancing the expression of MHC II, CD80 and CD86. These observations indicate the modulatory role of plant lectins in leishmaniasis vaccination may be related to their action on the initial innate response.

  15. Bacterial Isolation by Lectin-Modified Microengines

    PubMed Central

    Campuzano, Susana; Orozco, Jahir; Kagan, Daniel; Guix, Maria; Gao, Wei; Sattayasamitsathit, Sirilak; Claussen, Jonathan C.; Merkoçi, Arben; Wang, Joseph

    2011-01-01

    New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct and label-free optical visualization of the captured bacteria and discrimination against non-target cells. PMID:22136558

  16. Interactions between Rhizobia and Lectins of Lentil, Pea, Broad Bean, and Jackbean 1

    PubMed Central

    Wong, Peter P.

    1980-01-01

    A quantitative method was developed to measure the binding of fluorescent-labeled lentil (Lens esculenta Moench), pea (Pisum sativum L.), broad bean (Vicia faba L.), and jackbean (Canavalia ensiformis L., DC.) lectins to various Rhizobium strains. Lentil lectin bound to three of the five Rhizobium leguminosarum strains tested. The number of lentil lectin molecules bound per R. leguminosarum 128C53 cell was 2.1 × 104. Lentil lectin also bound to R. japonicum 61A133. Pea and broad bean lectins bound to only two of the five strains of R. leguminosarum, whereas concanavalin A (jackbean lectin) bound to all strains of R. leguminosarum, R. phaseoli, R. japonicum, and R. sp. tested. Since these four lectins have similar sugarbinding properties but different physical properties, the variation in bindings of these lectins to various Rhizobium strains indicates that binding of lectin to Rhizobium is determined not only by the sugar specificity of the lectin but also by its physical characteristics. The binding of lentil lectin and concanavalin A to R. leguminosarum 128C53 could be inhibited by glucose, fructose, and mannose. However, even at 150 millimolar glucose, about 15% of the binding remained. The binding of lentil lectin to R. japonicum 61A133 could be inhibited by glucose but not by galactose. It is concluded that the binding site of lentil lectin to R. japonicum is different from the binding site of soybean lectin to R. japonicum. PMID:16661328

  17. A multiplex lectin-channel monitoring method for human serum glycoproteins by quantitative mass spectrometry.

    PubMed

    Ahn, Yeong Hee; Ji, Eun Sun; Shin, Park Min; Kim, Kwang Hoe; Kim, Yong-Sam; Ko, Jeong Heon; Yoo, Jong Shin

    2012-02-01

    A mass profiling method and multiple reaction monitoring (MRM)-based quantitative approach were used to analyze multiple lectin-captured fractions of human serum using different lectins such as aleuria aurantia lectin (AAL), phytohemagglutinin-L(4) (L-PHA), concanavalin A (Con A), and Datura stramonium agglutinin (DSA) to quantitatively monitor protein glycosylation diversity. Each fraction, prepared by multiple lectin-fractionation and tryptic digestion, was analyzed by 1-D LC-MS/MS. Semi-quantitative profiling showed that the list of glycoproteins identified from each lectin-captured fraction is significantly different according to the used lectin. Thus, it was confirmed that the multiplex lectin-channel monitoring (LCM) using multiple lectins is useful for investigating protein glycosylation diversity in a proteome sample. Based on the semi-quantitative mass profiling, target proteins showing lectin-specificity among each lectin-captured fraction were selected and analyzed by the MRM-based method in triplicate using each lectin-captured fraction (average CV 7.9%). The MRM-based analysis for each lectin-captured fraction was similar to those obtained by the profiling experiments. The abundance of each target protein measured varied dramatically, based on the lectin-specificity. The multiplex LCM approach using MRM-based analyses is useful for quantitatively monitoring target protein glycoforms selectively fractionated by multiple lectins. Thus through multiplex LCM rather than single, we could inquire minutely into protein glycosylation states. PMID:22158852

  18. The effect of lectins on Cryptosporidium parvum oocyst in vitro attachment to host cells.

    PubMed

    Stein, Barry; Stover, Larry; Gillem, Ashley; Winters, Katherine; Leet, John H; Chauret, Christian

    2006-02-01

    The influence of lectins on Cryptosporidium parvum oocyst agglutination and on attachment to both fixed Madin Darby Canine Kidney (MDCK) cells and fixed HCT-8 (human colorectal epithelial) cells was examined. Oocyst cell wall characteristics were examined by transmission electron microscopy. Lectin-free oocysts were shown to adhere equally to both MDCK cells and HCT-8 cells. In MDCK cells, the addition of 1-25 microg/ml Codium fragile lectin, 10 microg/ml Maclura pomifera lectin, 10 microg/ml Helix pomatia lectin, and 10-200 microg/ml Artocarpus integrifolia lectin significantly increased attachment to at least 1 of the cell cultures as compared to oocysts incubated without any lectin. The lectin-enhanced attachment was reversed by co-incubation of lectin treated-oocysts with 250 mM of each specific sugar (for a given lectin). In agglutination assays, concentrations as low as 0.5 microg/ml of C. fragile, M. pomifera, and A. integrifolia lectin agglutinated oocysts within 60 min. Finally, in TEM samples, colloidal gold conjugated-lectins from A. integrifolia, C. fragile, H. pomatia, and M. pomifera attached to oocysts, and this could be competitively inhibited by a lectin-specific sugar. This suggests that C. parvum oocysts are highly reactive to N-acetyl galactosamine-binding lectins and that the presence of N-acetyl-galactosamine containing molecules on oocysts can potentially help in oocyst attachment to host cells.

  19. Mechanisms involved in Korean mistletoe lectin-induced apoptosis of cancer cells

    PubMed Central

    Khil, Lee-Yong; Kim, Wi; Lyu, Suyun; Park, Won Bong; Yoon, Ji-Won; Jun, Hee-Sook

    2007-01-01

    AIM: To investigate the anti-cancer mechanisms of Korean mistletoe lectin (Viscum album coloratum agglutinin, VCA) using a human colon cancer cell line (COLO). METHODS: Cytotoxic effects of VCA on COLO cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro and tumor-killing effects in vivo. To study the mechanisms involved, the expression of various pro-caspases, anti-apoptotic proteins, and death receptors was determined by western blot. To determine which death receptor is involved in VCA-induced apoptosis of COLO cells, cytotoxicity was examined by MTT assay after treatment with agonists or antagonists of death receptors. RESULTS: VCA killed COLO cells in a time- and dose-dependent manner and induced complete regression of tumors in nude mice transplanted with COLO cells. Treatment of COLO cells with VCA activated caspase-2, -3, -8, and -9 and decreased expression of anti-apoptotic molecules including receptor interacting protein, nuclear factor-κB, X-linked inhibitor of apoptosis protein, and Akt/protein kinase B. We then examined the involvement of death receptors in VCA-induced apoptosis. Only tumor necrosis factor receptor 1, among the death receptors examined, was involved in apoptosis of COLO cells, evidenced by inhibition of VCA-induced apoptosis and decreased activation of caspases, particularly caspase-8, by tumor necrosis factor receptor 1 antagonizing antibody. CONCLUSION: VCA-induced apoptotic COLO cell death is due to the activation of caspases and inhibition of anti-apoptotic proteins, in part through the tumor necrosis factor receptor 1 signaling pathway. PMID:17569116

  20. Assessment of Sauromatum guttatum lectin toxicity against Bactrocera cucurbitae.

    PubMed

    Kaur, Manpreet; Thakur, Kshema; Kamboj, Sukhdev Singh; Kaur, Satwinder; Kaur, Amritpal; Singh, Jatinder

    2015-11-01

    Lectins are proteins that bind specifically to foreign glycans. Due to this binding property, these molecules have potential application as bioinsecticidal tools replacing conventional chemical insecticides. The present study involved purification of phytolectin from the tubers of Sauromatum guttatum by affinity chromatography on asialofetuin-linked silica matrix. The purity of the sample was checked by SDS-PAGE at pH 8.3. Purified lectin was incorporated in the artificial diet of a Dipteran model, Bactrocera cucurbitae at different concentrations (10, 20, 40, 60 and 80 µgml(-1)). The lectin significantly affected various developmental parameters that were studied. Percentage pupation and percentage emergence was reduced to 44 % and 7.9%, respectively, at 80 µgml(-1) concentration as compared to control (100%). LC50 of Sauromatum guttatum lectin was calculated to be 19.42 µgml(-1). Treatment of insect larvae with LC50 of Sauromatum guttatum lectin suppressed the activity of hydrolytic enzymes (esterases and acid phosphatases) and oxidative enzymes (superoxide dismutase and glutathione-S-transferase). Thus, with low LC50 and high mortality (approximately 92% at 80 µgml(-1)) of the insect larvae, Sauromatum guttatum lectin offers a possibility to engineer crop plants for improved and safer agriculture. PMID:26688959

  1. Antifungal activity of lectins against yeast of vaginal secretion

    PubMed Central

    Gomes, Bruno Severo; Siqueira, Ana Beatriz Sotero; de Cássia Carvalho Maia, Rita; Giampaoli, Viviana; Teixeira, Edson Holanda; Arruda, Francisco Vassiliepe Sousa; do Nascimento, Kyria Santiago; de Lima, Adriana Nunes; Souza-Motta, Cristina Maria; Cavada, Benildo Sousa; Porto, Ana Lúcia Figueiredo

    2012-01-01

    Lectins are carbohydrate-binding proteins of non-imune origin. This group of proteins is distributed widely in nature and they have been found in viruses, microorganisms, plants and animals. Lectins of plants have been isolated and characterized according to their chemical, physical-chemical, structural and biological properties. Among their biological activities, we can stress its fungicidal action. It has been previously described the effect of the lectins Dviol, DRL, ConBr and LSL obtained from the seeds of leguminous plants on the growth of yeasts isolated from vaginal secretions. In the present work the experiments were carried out in microtiter plates and the results interpreted by both methods: visual observations and a microplate reader at 530nm. The lectin concentrations varied from 0.5 to 256μg/mL, and the inoculum was established between 65-70% of trammitance. All yeast samples isolated from vaginal secretion were evaluated taxonomically, where were observed macroscopic and microscopic characteristics to each species. The LSL lectin did not demonstrate any antifungal activity to any isolate studied. The other lectins DRL, ConBr and DvioL, showed antifungal potential against yeast isolated from vaginal secretion. These findings offering offer a promising field of investigation to develop new therapeutic strategies against vaginal yeast infections, collaborating to improve women's health. PMID:24031889

  2. Chemical modification studies of Artocarpus lakoocha lectin artocarpin.

    PubMed

    Chowdhury, S; Ahmed, H; Chatterjee, B P

    1991-05-01

    The effect of chemical modification on an anti T-like lectin, artocarpin isolated from Artocarpus lakoocha seeds was investigated in order to identify the type of amino acids involved in its agglutinating activity. Modification of carboxyl groups, arginine and lysine residues, did not affect the lectin activity. However, modification of tryptophan, tyrosine and histidine residues led to a complete loss of its activity, indicating the involvement of these amino acids in the saccharide-binding ability. A protection was observed in the presence of inhibitory sugar. A marked decrease in the fluorescence emission was found when the tryptophan residues of lectin were modified. The circular dichroism spectra showed the presence of an identical pattern of conformation in the native and modified lectin, indicating that the loss in activity was due to modification only. The effect of pronase on artocarpin showed loss of activity whereas papain and trypsin had no effect. The specific activity of artocarpin remained unaltered on treatment with glycosidases but remarkable increase in the activity (of the same) was observed with xylanase treatment. Immunodiffusion studies with chemically modified lectin showed no gross structural changes, indicating that the group specific modifying agents did not alter the antigenic sites of the modified lectin.

  3. Identification of lectin binding proteins in human tears.

    PubMed

    Kuizenga, A; van Haeringen, N J; Kijlstra, A

    1991-12-01

    The identity of glycoproteins in stimulated normal human tears was investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of tears onto minigels, blotting, and subsequent incubation with different biotinylated lectins (concanavalin A [Con A], peanut agglutinin [PNA], glycine max agglutinin [SBA], Phaseolus vulgaris agglutinin, wheat germ agglutinin [WGA, native form], Artocarpus integrifolia agglutinin [Jacalin], and Pisum sativum agglutinin). Control proteins included purified secretory immunoglobulin A (sIgA) from human colostrum, human milk lactoferrin, and chicken-egg lysozyme. All samples were prepared in a denaturing (SDS) buffer under nonreducing and reducing conditions. The sIgA in tears and IgA (alpha) heavy chain fragments (reduced sample) were identified with most of the lectins tested. A particular high molecular weight (greater than 200 kD) protein fraction in tears that just entered the separation gel on SDS-PAGE was detected with WGA and Jacalin. This fraction stain poorly with silver. Tear lactoferrin was identified with all lectins used, although binding was low with SBA. Purified milk lactoferrin showed a poor reaction with Jacalin, but a protein in tears of similar mobility bound this lectin (nonreduced samples). Under both nonreducing and reducing conditions, tear-specific prealbumin in tears did not bind any of the lectins tested. Tear lysozyme only reacted with lectin after reduction. The techniques described may provide additional valuable information in addition to commonly used methods for tear protein analysis and further knowledge concerning the role of glycoproteins on the ocular surface.

  4. Purification and cDNA cloning of a lectin and a lectin-like protein from Apios americana Medikus tubers.

    PubMed

    Kouzuma, Yoshiaki; Irie, Satoshi; Yamazaki, Rikiya; Yonekura, Masami

    2014-01-01

    An Apios americana lectin (AAL) and a lectin-like protein (AALP) were purified from tubers by chromatography on Butyl-Cellulofine, ovomucoid-Cellulofine, and DEAE-Cellulofine columns. AAL showed strong hemagglutinating activity toward chicken and goose erythrocytes, but AALP showed no such activity toward any of the erythrocytes tested. The hemagglutinating activity of AAL was not inhibited by mono- or disaccharides, but was inhibited by glycoproteins, such as asialofetuin and ovomucoid, suggesting that AAL is an oligosaccharide-specific lectin. The cDNAs of AAL and AALP consist of 1,093 and 1,104 nucleotides and encode proteins of 302 and 274 amino acid residues, respectively. Both amino acid sequences showed high similarity to known legume lectins, and those of their amino acids involved in carbohydrate and metal binding were conserved. PMID:25036952

  5. Lectin bioconjugates trigger urothelial cytoinvasion--a glycotargeted approach for improved intravesical drug delivery.

    PubMed

    Neutsch, L; Eggenreich, B; Herwig, E; Marchetti-Deschmann, M; Allmaier, G; Gabor, F; Wirth, M

    2012-10-01

    A unique structural and functional configuration renders the human urothelium, one of the hardest to overcome biological barriers, and accounts for critical shortcomings in the adjuvant localized therapy of bladder cancer and other severe medical conditions. Strategies to improve intravesical drug absorption are urgently sought, but so far have hardly adopted biorecognitive delivery vectors that are more specifically tailored to the natural characteristics of the target site. The efficient cytoinvasion of uropathogenic bacteria, mediated via a mannose-directed FimH lectin adhesin, and malignancy-dependent differences in bladder cell glycosylation point to considerable unrealized potential of lectins as targeting vectors on the molecular/functional and recognitive level. Here, we outline the ability of wheat germ agglutinin (WGA) to induce endocytosis of conjugated payload in human urothelial SV-HUC-1 cells after stable adhesion to internalizing receptors. A panel of model bioconjugates was prepared by covalently coupling one to six WGA units to fluorescein-labeled bovine serum albumin (fBSA). Cytoadhesive capacity was found to directly correlate to the degree of modification up to a critical threshold of on average three targeting ligands per conjugate. The highly specific, glycan-triggered interaction proved essential for endosomal sorting and was followed by rapid (<60min) and extensive (>40%) internalization. fBSA/WGA bioconjugates were processed analogously to the free lectin, irrespective of the significantly higher molecular weight (100-300kD). Durable entrapment of conjugates in acidic, perinuclear compartments without kiss-and-run recycling to the plasma membrane was found in both single cells and monolayers. Our results assign promising potential to glycotargeted delivery concepts in the intravesical setting and offer new perspectives for the application of complex biologicals in the urinary tract. PMID:22889683

  6. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation

    PubMed Central

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I; Lindahl, Erik; Elinder, Fredrik

    2016-01-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions – a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd2+ bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K+ coordination, a hallmark for C-type inactivation. An engineered Cd2+ bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel. PMID:27278891

  7. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation

    NASA Astrophysics Data System (ADS)

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I.; Lindahl, Erik; Elinder, Fredrik

    2016-06-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions - a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd2+ bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K+ coordination, a hallmark for C-type inactivation. An engineered Cd2+ bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel.

  8. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation

    NASA Astrophysics Data System (ADS)

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I.; Lindahl, Erik; Elinder, Fredrik

    2016-06-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions – a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd2+ bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K+ coordination, a hallmark for C-type inactivation. An engineered Cd2+ bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel.

  9. Reciprocal voltage sensor-to-pore coupling leads to potassium channel C-type inactivation.

    PubMed

    Conti, Luca; Renhorn, Jakob; Gabrielsson, Anders; Turesson, Fredrik; Liin, Sara I; Lindahl, Erik; Elinder, Fredrik

    2016-01-01

    Voltage-gated potassium channels open at depolarized membrane voltages. A prolonged depolarization causes a rearrangement of the selectivity filter which terminates the conduction of ions - a process called slow or C-type inactivation. How structural rearrangements in the voltage-sensor domain (VSD) cause alteration in the selectivity filter, and vice versa, are not fully understood. We show that pulling the pore domain of the Shaker potassium channel towards the VSD by a Cd(2+) bridge accelerates C-type inactivation. Molecular dynamics simulations show that such pulling widens the selectivity filter and disrupts the K(+) coordination, a hallmark for C-type inactivation. An engineered Cd(2+) bridge within the VSD also affect C-type inactivation. Conversely, a pore domain mutation affects VSD gating-charge movement. Finally, C-type inactivation is caused by the concerted action of distant amino acid residues in the pore domain. All together, these data suggest a reciprocal communication between the pore domain and the VSD in the extracellular portion of the channel. PMID:27278891

  10. Structures and binding specificity of galactose- and mannose-binding lectins from champedak: differences from jackfruit lectins.

    PubMed

    Gabrielsen, Mads; Abdul-Rahman, Puteri Shafinaz; Othman, Shatrah; Hashim, Onn H; Cogdell, Richard J

    2014-06-01

    Galactose-binding and mannose-binding lectins from the champedak fruit, which is native to South-east Asia, exhibit useful potential clinical applications. The specificity of the two lectins for their respective ligands allows the detection of potential cancer biomarkers and monitoring of the glycosylated state of proteins in human serum and/or urine. To fully understand and expand the use of these natural proteins, their complete sequences and crystal structures are presented here, together with details of sugar binding.

  11. New low-Ni (igneous?) particles among the C and C? types of cosmic dust

    NASA Astrophysics Data System (ADS)

    Flynn, G. J.; Sutton, S. R.; Bajt, S.; Kloeck, W.

    1993-03-01

    Low-Ni particles with major element abundances, optical properties, and morphologies sufficiently similar to chondritic interplanetery dust particles (IDP's) to receive JSC Cosmic Dust Catalog classifications of C or C?-types were shown to have trace element contents and mineralogies similar to igneous material. Examination of the JSC Catalog EDX spectra by Cooke et al. has shown that 13 percent of the C-type and 38 percent of the C?-type particles are potentially low-Ni particles. Two new low-Ni particles were identified, and it was shown that an additional fragment from the L2002*C cluster has an igneous composition. A newly analyzed fragment of the W7066*A cluster has a chondritic composition. The W7066*A cluster is important because it has yielded a fragment of igneous composition and another fragment having high concentrations of He and Ne suggesting an extraterrestrial origin.

  12. c-Type Cytochromes and Manganese Oxidation in Pseudomonas putida MnB1

    PubMed Central

    Caspi, Ron; Tebo, Bradley M.; Haygood, M. G.

    1998-01-01

    Pseudomonas putida MnB1 is an isolate from an Mn oxide-encrusted pipeline that can oxidize Mn(II) to Mn oxides. We used transposon mutagenesis to construct mutants of strain MnB1 that are unable to oxidize manganese, and we characterized some of these mutants. The mutants were divided into three groups: mutants defective in the biogenesis of c-type cytochromes, mutants defective in genes that encode key enzymes of the tricarboxylic acid cycle, and mutants defective in the biosynthesis of tryptophan. The mutants in the first two groups were cytochrome c oxidase negative and did not contain c-type cytochromes. Mn(II) oxidation capability could be recovered in a c-type cytochrome biogenesis-defective mutant by complementation of the mutation. PMID:9758766

  13. COMMON CELL SURFACE ANTIGEN ASSOCIATED WITH MAMMALIAN C-TYPE RNA VIRUSES

    PubMed Central

    Yoshiki, Takashi; Mellors, Robert C.; Hardy, William D.; Fleissner, Erwin

    1974-01-01

    The indirect membrane immunofluorescence test and the absorption analysis of rabbit anti-FeLV, rabbit anti-FeLVp 30, and rabbit anti-MuLVp 30 antisera yielded the following conclusions. An antigen shared by mammalian (murine and feline) C-type RNA leukemia and sarcoma viruses was detected on the surface of cells infected or transformed by C-type viruses. The antigen was characterized as membrane-bound gs antigen bearing two determinants, membrane-bound gs-1, intraspecies-specific antigenic determinant, and membrane-bound gs-3, interspecies-specific antigenic determinant. Membrane-bound gs antigen was located on the cell surface, frequently near the site of virus budding but not on the envelope of murine C-type RNA virus. PMID:4131513

  14. c-Type cytochromes and manganese oxidation in Pseudomonas putida MnB1

    SciTech Connect

    Caspi, R.; Tebo, B.M.; Haygood, M.G.

    1998-10-01

    Pseudomonas putida MnB1 is an isolate from an Mn oxide-encrusted pipeline that can oxidize Mn(II) to Mn oxides. The authors used transposon mutagenesis to construct mutants of strain MnB1 that are unable to oxidize manganese, and they characterized some of these mutants. The mutants were divided into three groups: mutants defective in the biogenesis of c-type cytochromes, mutants defective in genes that encode key enzymes of the tricarboxylic acid cycle, and mutants defective in the biosynthesis of tryptophan. The mutants in the first two groups were cytochrome c oxidase negative and did not contain c-type cytochromes. Mn(II) oxidation capability could be recovered in a c-type cytochrome biogenesis-defective mutant by complementation of the mutation.

  15. Evidence for a Lectin Specific for Sulfated Glycans in the Salivary Gland of the Malaria Vector, Anopheles gambiae

    PubMed Central

    Francischetti, Ivo M. B.; Ma, Dongying; Andersen, John F.; Ribeiro, José M. C.

    2014-01-01

    Salivary gland homogenate (SGH) from the female mosquitoes Anopheles gambiae, An. stephensi, An. freeborni, An. dirus and An. albimanus were found to exhibit hemagglutinating (lectin) activity. Lectin activity was not found for male An. gambiae, or female Ae aegypti, Culex quinquefasciatus, Phlebotomus duboscqi, and Lutzomyia longipalpis. With respect to species-specificity, An. gambiae SGH agglutinates red blood cells (RBC) from humans, horse, sheep, goat, pig, and cow; it is less active for rats RBC, and not detectable for guinea-pigs or chicken RBC. Notably, lectin activity was inhibited by low concentrations of dextran sulfate 50–500 K, fucoidan, heparin, laminin, heparin sulfate proteoglycan, sialyl-containing glycans (e.g. 3′-sialyl Lewis X, and 6′-sialyl lactose), and gangliosides (e.g. GM3, GD1, GD1b, GTB1, GM1, GQ1B), but not by simple sugars. These results imply that molecule(s) in the salivary gland target sulfated glycans. SGH from An. gambiae was also found to promote agglutination of HL-60 cells which are rich in sialyl Lewis X, a glycan that decorates PSGL-1, the neutrophils receptor that interacts with endothelial cell P-selectin. Accordingly, SGH interferes with HL-60 cells adhesion to immobilized P-selectin. Because An. gambiae SGH expresses galectins, one member of this family (herein named Agalectin) was expressed in E. coli. Recombinant Agalectin behaves as a non-covalent homodimer. It does not display lectin activity, and does not interact with 500 candidates tested in a Glycan microarray. Gel-filtration chromatography of the SGH of An. gambiae identified a fraction with hemagglutinating activity, which was analyzed by 1D PAGE followed by in-gel tryptic digestion, and nano-LC MS/MS. This approach identified several genes which emerge as candidates for a lectin targeting sulfated glycans, the first with this selectivity to be reported in the SGH of a blood-sucking arthropod. The role of salivary molecules (sialogenins) with lectin

  16. Evidence for a lectin specific for sulfated glycans in the salivary gland of the malaria vector, Anopheles gambiae.

    PubMed

    Francischetti, Ivo M B; Ma, Dongying; Andersen, John F; Ribeiro, José M C

    2014-01-01

    Salivary gland homogenate (SGH) from the female mosquitoes Anopheles gambiae, An. stephensi, An. freeborni, An. dirus and An. albimanus were found to exhibit hemagglutinating (lectin) activity. Lectin activity was not found for male An. gambiae, or female Ae aegypti, Culex quinquefasciatus, Phlebotomus duboscqi, and Lutzomyia longipalpis. With respect to species-specificity, An. gambiae SGH agglutinates red blood cells (RBC) from humans, horse, sheep, goat, pig, and cow; it is less active for rats RBC, and not detectable for guinea-pigs or chicken RBC. Notably, lectin activity was inhibited by low concentrations of dextran sulfate 50-500 K, fucoidan, heparin, laminin, heparin sulfate proteoglycan, sialyl-containing glycans (e.g. 3'-sialyl Lewis X, and 6'-sialyl lactose), and gangliosides (e.g. GM3, GD1, GD1b, GTB1, GM1, GQ1B), but not by simple sugars. These results imply that molecule(s) in the salivary gland target sulfated glycans. SGH from An. gambiae was also found to promote agglutination of HL-60 cells which are rich in sialyl Lewis X, a glycan that decorates PSGL-1, the neutrophils receptor that interacts with endothelial cell P-selectin. Accordingly, SGH interferes with HL-60 cells adhesion to immobilized P-selectin. Because An. gambiae SGH expresses galectins, one member of this family (herein named Agalectin) was expressed in E. coli. Recombinant Agalectin behaves as a non-covalent homodimer. It does not display lectin activity, and does not interact with 500 candidates tested in a Glycan microarray. Gel-filtration chromatography of the SGH of An. gambiae identified a fraction with hemagglutinating activity, which was analyzed by 1D PAGE followed by in-gel tryptic digestion, and nano-LC MS/MS. This approach identified several genes which emerge as candidates for a lectin targeting sulfated glycans, the first with this selectivity to be reported in the SGH of a blood-sucking arthropod. The role of salivary molecules (sialogenins) with lectin activity is

  17. Physiological roles of asialoglycoprotein receptors (ASGPRs) variants and recent advances in hepatic-targeted delivery of therapeutic molecules via ASGPRs.

    PubMed

    Hu, Jing; Liu, Jia; Yang, Dongliang; Lu, Mengji; Yin, Jian

    2014-01-01

    The asialoglycoprotein receptor (ASGPR) is a high-capacity C-type lectin receptor mainly expressed on mammalian hepatic cells. The physiological function of ASGPR has not been completely clarified and is thought to be specific binding and internalization of galactose (Gal) or N-acetylgalactosamine (GalNAc)-terminating glycoproteins by hepatocytes. The human ASGPR is comprised of two homologous polypeptides, H1 and H2. ASGPR H1 has two splice variants (H1a and H1b) and ASGPR H2 has three splice variants (H2a, H2b, and H2c). These variants have been discovered to exist both in human liver tissues and in human hepatoma cells. Variant H1b, which has an in-frame deletion of exon 2 resulting in the loss of the transmembrane domain and is secreted as a soluble protein, encodes functional soluble ASGPR (s- ASGPR). Based on our previous results, we proposed the possible physiological function of s-ASGPR, which is well interpreted in the Galactosyl Homeostasis Hypothesis proposed by Weigel. ASGPR is one of the most promising targets for hepatic delivery. In this review, the recent progresses of cationic polysomes and liposomes as effective non-viral delivery system via ASGPR are also presented.

  18. Molecular Cloning and Functional Characterization of Mannose Receptor in Zebra Fish (Danio rerio) during Infection with Aeromonas sobria.

    PubMed

    Zheng, Feifei; Asim, Muhammad; Lan, Jiangfeng; Zhao, Lijuan; Wei, Shun; Chen, Nan; Liu, Xiaoling; Zhou, Yang; Lin, Li

    2015-01-01

    Mannose receptor (MR) is a member of pattern-recognition receptors (PRRs), which plays a significant role in immunity responses. Much work on MR has been done in mammals and birds while little in fish. In this report, a MR gene (designated as zfMR) was cloned from zebra fish (Danio rerio), which is an attractive model for the studies of animal diseases. The full-length cDNA of zfMR contains 6248 bp encoding a putative protein of 1428 amino acids. The predicted amino acid sequences showed that zfMR contained a cysteine-rich domain, a single fibronectin type II (FN II) domain, eight C-type lectin-like domains (CTLDs), a transmembrane domain and a short C-terminal cytoplasmic domain, sharing highly conserved structures with MRs from the other species. The MR mRNA could be detected in all examined tissues with highest level in kidney. The temporal expression patterns of MR, IL-1β and TNF-α mRNAs were analyzed in the liver, spleen, kidney and intestine post of infection with Aeromonas sobria. By immunohistochemistry assay, slight enhancement of MR protein was also observed in the spleen and intestine of the infected zebra fish. The established zebra fish-A. sobria infection model will be valuable for elucidating the role of MR in fish immune responses to infection. PMID:25988382

  19. Molecular Cloning and Functional Characterization of Mannose Receptor in Zebra Fish (Danio rerio) during Infection with Aeromonas sobria

    PubMed Central

    Zheng, Feifei; Asim, Muhammad; Lan, Jiangfeng; Zhao, Lijuan; Wei, Shun; Chen, Nan; Liu, Xiaoling; Zhou, Yang; Lin, Li

    2015-01-01

    Mannose receptor (MR) is a member of pattern-recognition receptors (PRRs), which plays a significant role in immunity responses. Much work on MR has been done in mammals and birds while little in fish. In this report, a MR gene (designated as zfMR) was cloned from zebra fish (Danio rerio), which is an attractive model for the studies of animal diseases. The full-length cDNA of zfMR contains 6248 bp encoding a putative protein of 1428 amino acids. The predicted amino acid sequences showed that zfMR contained a cysteine-rich domain, a single fibronectin type II (FN II) domain, eight C-type lectin-like domains (CTLDs), a transmembrane domain and a short C-terminal cytoplasmic domain, sharing highly conserved structures with MRs from the other species. The MR mRNA could be detected in all examined tissues with highest level in kidney. The temporal expression patterns of MR, IL-1β and TNF-α mRNAs were analyzed in the liver, spleen, kidney and intestine post of infection with Aeromonas sobria. By immunohistochemistry assay, slight enhancement of MR protein was also observed in the spleen and intestine of the infected zebra fish. The established zebra fish-A. sobria infection model will be valuable for elucidating the role of MR in fish immune responses to infection. PMID:25988382

  20. Lectin histochemistry reveals SNA as a prognostic carbohydrate-dependent probe for invasive ductal carcinoma of the breast: a clinicopathological and immunohistochemical auxiliary tool

    PubMed Central

    dos-Santos, Petra B; Zanetti, Juliana S; Vieira-de-Mello, Gabriela S; Rêgo, Moacyr BM; A, Alfredo Ribeiro-Silva; Beltrão, Eduardo Isidoro Carneiro

    2014-01-01

    Increased sialylation and β1,6-branched oligosaccharides has been associated with a variety of structural changes in cell surface carbohydrates, most notably in tumorigenesis. Lectins are defined as proteins that preferentially recognize and bind carbohydrate complexes protruding from glycolipids and glycoproteins. This interaction with carbohydrates can be as specific as the interaction between antigen and antibody. Due to this type of interaction lectins have been used as experimental auxiliary tools in histopathological diagnosis of cancer. This study was designed to evaluate the differential expression of sialic acids and β1,6-N-acetylglucosaminyltransferase V (MGAT5) in invasive (IDC) and in situ (DCIS) ductal carcinoma of the breast and its possible application as prognostic biomarkers. A possible transition between pre-malign and malign lesions was evaluated using DCIS samples. Biopsies were analyzed regarding the expression of MUC1, p53, Ki-67, estrogen receptor, progesterone receptor, HER-2 and MGAT5. α2,6-linked sialic acids residues recognized by SNA lectin was overexpressed in 33.3% of IDC samples and it was related with Ki-67 (p=0.042), PR (p=0.029), lymphnodes status (p=0.017) and death (p=0.011). Regarding survival analysis SNA was the only lectin able to correlate with specific-disease survival and disease-free survival (p=0.024 and p=0.041, respectively), besides, it presents itself as an independent variable by Cox Regression analysis (p= 0.004). Comparing IDC and DCIS cases, only SNA showed different staining pattern (p=0.034). The presence of sialic acids on tumor cell surface can be an indicative of poor prognosis and our study provides further evidence that SNA lectin can be used as a prognostic probe in IDC and DCIS patients. PMID:24966944

  1. MytiLec, a Mussel R-Type Lectin, Interacts with Surface Glycan Gb3 on Burkitt’s Lymphoma Cells to Trigger Apoptosis through Multiple Pathways

    PubMed Central

    Hasan, Imtiaj; Sugawara, Shigeki; Fujii, Yuki; Koide, Yasuhiro; Terada, Daiki; Iimura, Naoya; Fujiwara, Toshiyuki; Takahashi, Keisuke G.; Kojima, Nobuhiko; Rajia, Sultana; Kawsar, Sarkar M. A.; Kanaly, Robert A.; Uchiyama, Hideho; Hosono, Masahiro; Ogawa, Yukiko; Fujita, Hideaki; Hamako, Jiharu; Matsui, Taei; Ozeki, Yasuhiro

    2015-01-01

    MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt's lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface. PMID:26694420

  2. Conidiogenic effects of mannose-binding lectins isolated from cotyledons of red kidney bean (Phaseolus vulgaris) on Alternaria alternata.

    PubMed

    Alizadeh, Hossein; Leung, David W M; Cole, Anthony L J

    2011-01-01

    Effect of proteinaceous extracts from red kidney bean cotyledons on mycelium of Alternaria alternata growing on potato dextrose agar (PDA) plates was investigated. Unexpectedly, conidia formation was induced in response to applied crude extracts. A PDA disc method was developed to quantify conidia formed. A purified fraction retaining conidiation inducing effect (CIE) was obtained following several protein purification procedures including the last step of eluting bound proteins from an Affi-gel blue gel column. Based on MALDI (matrix assisted laser desorption/ionization) mass spectrometric analysis, a previously identified mannose-binding lectin (MBL) called PvFRIL (Phaseolus vulgaris fetal liver tyrosine kinase 3-receptor interacting lectin) was present in this conidiation inducing fraction. The PvFRIL was subsequently purified using a single step mannose-agarose affinity column chromatography. When the lectin was applied exogenously to A. alternata, increased conidiation resulted. The conidia produced in response to the MBL were similar to those induced by other methods and their germ tubes were longer after 12 h growth than those induced under white light. To our knowledge this is the first report of exogenous application of a PvFRIL or another purified protein from a plant inducing conidia formation in a fungus. PMID:21112064

  3. Sampling of Glycan-Bound Conformers by the Anti-HIV Lectin Oscillatoria agardhii agglutinin in the Absence of Sugar.

    PubMed

    Carneiro, Marta G; Koharudin, Leonardus M I; Ban, David; Sabo, T Michael; Trigo-Mourino, Pablo; Mazur, Adam; Griesinger, Christian; Gronenborn, Angela M; Lee, Donghan

    2015-05-26

    Lectins from different sources have been shown to interfere with HIV infection by binding to the sugars of viral-envelope glycoproteins. Three-dimensional atomic structures of a number of HIV-inactivating lectins have been determined, both as free proteins and in glycan-bound forms. However, details on the mechanism of recognition and binding to sugars are elusive. Herein we focus on the anti-HIV lectin OAA from Oscillatoria agardhii: We show that in the absence of sugars in solution, both the sugar-free and sugar-bound protein conformations that were observed in the X-ray crystal structures exist as conformational substates. Our results suggest that glycan recognition occurs by conformational selection within the ground state; this model differs from the popular "excited-state" model. Our findings provide further insight into molecular recognition of the major receptor on the HIV virus by OAA. These details can potentially be used for the optimization and/or development of preventive anti-HIV therapeutics. PMID:25873445

  4. Synthesis of mannoheptose derivatives and their evaluation as inhibitors of the lectin LecB from the opportunistic pathogen Pseudomonas aeruginosa.

    PubMed

    Hofmann, Anna; Sommer, Roman; Hauck, Dirk; Stifel, Julia; Göttker-Schnetmann, Inigo; Titz, Alexander

    2015-08-14

    Biofilm formation and chronic infections with Pseudomonas aeruginosa depend on lectins produced by the bacterium. The bacterial C-type lectin LecB binds to the two monosaccharides l-fucose and d-mannose and conjugates thereof. Previously, d-mannose derivatives with amide and sulfonamide substituents at C6 were reported as potent inhibitors of the bacterial lectin LecB and LecB-mediated bacterial surface adhesion. Because d-mannose establishes a hydrogen bond via its 6-OH group with Ser23 of LecB in the crystal structure and may be beneficial for binding affinity, we extended d-mannose and synthesized mannoheptoses bearing the free 6-OH group as well as amido and sulfonamido-substituents at C7. Two series of diastereomeric mannoheptoses were synthesized and the stereochemistry was determined by X-ray crystallography. The potency of the mannoheptoses as LecB inhibitors was assessed in a competitive binding assay. The data reveal a diastereoselectivity of LecB for (6S)-mannoheptose derivatives with increased activity over methyl α-d-mannoside.

  5. Interaction of human mannose-binding lectin (MBL) with Yersinia enterocolitica lipopolysaccharide.

    PubMed

    Kasperkiewicz, Katarzyna; Swierzko, Anna S; Bartlomiejczyk, Marcin A; Cedzynski, Maciej; Noszczynska, Magdalena; Duda, Katarzyna A; Michalski, Mateusz; Skurnik, Mikael

    2015-09-01

    The lipopolysaccharide (LPS) is involved in the interaction between Gram-negative pathogenic bacteria and host. Mannose-binding lectin (MBL), complement-activating soluble pattern-recognition receptor targets microbial glycoconjugates, including LPS. We studied its interactions with a set of Yersinia enterocolitica O:3 LPS mutants. The wild-type strain LPS consists of lipid A (LA) substituted with an inner core oligosaccharide (IC) which in turn is substituted either with the O-specific polysaccharide (OPS) or the outer core hexasaccharide (OC), and sometimes also with the enterobacterial common antigen (ECA). The LPS mutants produced truncated LPS, missing OPS, OC or both, or, in addition, different IC constituents or ECA. MBL bound to LA-IC, LA-IC-OPS and LA-IC-ECA but not LA-IC-OC structures. Moreover, LA-IC substitution with both OPS and ECA prevented the lectin binding. Sequential truncation of the IC heptoses demonstrated that the MBL targets the IC heptose region. Furthermore, microbial growth temperature influenced MBL binding; binding was stronger to bacteria grown at room temperature (22°C) than to bacteria grown at 37°C. In conclusion, our results demonstrate that MBL can interact with Y. enterocolitica LPS, however, the in vivo significance of that interaction remains to be elucidated. PMID:26188838

  6. A new gene family of single fibrinogen domain lectins in Mytilus.

    PubMed

    Gorbushin, A M; Iakovleva, N V

    2011-01-01

    In molluscs haemolymph lectins bearing fibrinogen-like domain (FREP) act as immune pattern-recognition receptors. A full-length cDNAs of MytFREP1 and MytFREP2 cloned from haemocytes of blue mussel Mytilus edulis encoded putative polypeptides of 230 and 241 amino acids. Both polypeptides consist of signal peptide and C-terminal fibrinogen-like domain. Immune functions of these molecules may be extrapolated from the close-related and functionally characterized lectin AiFREP from bay scallop, Argopecten irradians. However, immune challenge experiments with zymosan particles, Escherichia coli bacterium and cercariae of Himasthla elongata (Trematoda) failed to modulate MytFREP1 and MytFREP2 mRNA expression in M. edulis haemocytes. Hypothetically, it argues into rather high specificity of mechanisms triggering a differential expression of MytFREP genes. The search in the EST database revealed orthologous copies for described genes and portion of relatively similar genes from two close-related mytilids, Mytilus galloprovincialis and Mytilus californianus. We document the new multigene family of FREPs from bivalves of genus Mytilus. MytFREP family currently represented by 2 genes from M. edulis, 4 genes from M. californianus and 7 genes from M. galloprovincialis.

  7. The mammalian lectin galectin-8 induces RANKL expression, osteoclastogenesis, and bone mass reduction in mice

    PubMed Central

    Vinik, Yaron; Shatz-Azoulay, Hadas; Vivanti, Alessia; Hever, Navit; Levy, Yifat; Karmona, Rotem; Brumfeld, Vlad; Baraghithy, Saja; Attar-Lamdar, Malka; Boura-Halfon, Sigalit; Bab, Itai; Zick, Yehiel

    2015-01-01

    Skeletal integrity is maintained by the co-ordinated activity of osteoblasts, the bone-forming cells, and osteoclasts, the bone-resorbing cells. In this study, we show that mice overexpressing galectin-8, a secreted mammalian lectin of the galectins family, exhibit accelerated osteoclasts activity and bone turnover, which culminates in reduced bone mass, similar to cases of postmenopausal osteoporosis and cancerous osteolysis. This phenotype can be attributed to a direct action of galectin-8 on primary cultures of osteoblasts that secrete the osteoclastogenic factor RANKL upon binding of galectin-8. This results in enhanced differentiation into osteoclasts of the bone marrow cells co-cultured with galectin-8-treated osteoblasts. Secretion of RANKL by galectin-8-treated osteoblasts can be attributed to binding of galectin-8 to receptor complexes that positively (uPAR and MRC2) and negatively (LRP1) regulate galectin-8 function. Our findings identify galectins as new players in osteoclastogenesis and bone remodeling, and highlight a potential regulation of bone mass by animal lectins. DOI: http://dx.doi.org/10.7554/eLife.05914.001 PMID:25955862

  8. Neutrophil activation induced by the lectin KM+ involves binding to CXCR2.

    PubMed

    Pereira-da-Silva, Gabriela; Moreno, Andréa N; Marques, Fabiana; Oliver, Constance; Jamur, Maria Célia; Panunto-Castelo, Ademilson; Roque-Barreira, Maria Cristina

    2006-01-01

    The lectin KM+ from Artocarpus integrifolia, also known as artocarpin, induces neutrophil migration by haptotaxis. The interactions of KM+ with both neutrophils and the extracellular matrix depend on the lectin's ability to recognize mannose-containing glycans. In the present study, we characterized the binding of KM+ to human neutrophils and the responses stimulated by this binding. Exposure to KM+ results in cell polarization, formation of a lamellipodium, and induction of deep ruffles on the cell surface. By fluorescence microscopy, we observed that KM+ is distributed homogeneously over the cell surface. KM+/ligand complexes are rapidly internalized, reaching maximum intracellular concentrations at 120 min, and decreasing thereafter. Furthermore, KM+ binding to the surface of human neutrophils is inhibited by the specific sugars, d-mannose or mannotriose. KM+-induced neutrophil migration is inhibited by pertussis toxin as well as by inhibition of CXCR2 activity. These results suggest that the KM+ ligand on the neutrophil surface is a G protein-coupled receptor (GPCR). The results also suggest that neutrophil migration induced by KM+ involves binding to CXCR2.

  9. New elements in the C-type natriuretic peptide signaling pathway inhibiting swine in vitro oocyte meiotic resumption.

    PubMed

    Santiquet, Nicolas; Papillon-Dion, Emilie; Djender, Nadjib; Guillemette, Christine; Richard, François J

    2014-07-01

    C-type natriuretic peptide (CNP) and its cognate receptor, natriuretic peptide receptor (NPR) B, have been shown to promote cGMP production in granulosa/cumulus cells. Once transferred to the oocyte through the gap junctions, the cGMP inhibits oocyte meiotic resumption. CNP has been shown to bind another natriuretic receptor, NPR-C. NPR-C is known to interact with and degrade bound CNP, and has been reported to possess signaling functions. Therefore, NPR-C could participate in the control of oocyte maturation during swine in vitro maturation (IVM). Here, we examine the effect of CNP signaling on meiotic resumption, the amount of cGMP and gap junctional communication (GJC) regulation during swine IVM. The results show an inhibitory effect of CNP in inhibiting oocyte meiotic resumption in follicle-stimulating hormone (FSH)-stimulated IVM. We also found that an NPR-C-specific agonist (cANP([4-23])) is likely to play a role in maintaining meiotic arrest during porcine IVM when in the presence of a suboptimal dose of CNP. Moreover, we show that, even if CNP can increase intracellular concentration of cGMP in cumulus-oocyte complexes, cANP((4-23)) had no impact on cGMP concentration, suggesting a potential cGMP-independent signaling pathway related to NPR-C activation. These data support a potential involvement of cANP((4-23)) through NPR-C in inhibiting oocyte meiotic resumption while in the presence of a suboptimal dose of CNP. The regulation of GJC was not altered by CNP, cANP((4-23)), or the combination of CNP and cANP((4-23)), supporting their potential contribution in sending signals to the oocytes. These findings offer promising insights in to new elements of the signaling pathways that may be involved in inhibiting resumption of meiosis during FSH-stimulated swine IVM.

  10. Vascular Relaxation Induced by C-Type Natriuretic Peptide Involves the Ca2+/NO-Synthase/NO Pathway

    PubMed Central

    Andrade, Fernanda A.; Restini, Carolina B. A.; Grando, Marcella D.; Ramalho, Leandra N. Z.; Bendhack, Lusiane M.

    2014-01-01

    Aims C-type natriuretic peptide (CNP) and nitric oxide (NO) are endothelium-derived factors that play important roles in the regulation of vascular tone and arterial blood pressure. We hypothesized that NO produced by the endothelial NO-synthase (NOS-3) contributes to the relaxation induced by CNP in isolated rat aorta via activation of endothelial NPR-C receptor. Therefore, the aim of this study was to investigate the putative contribution of NO through NPR-C activation in the CNP induced relaxation in isolated conductance artery. Main Methods Concentration-effect curves for CNP were constructed in aortic rings isolated from rats. Confocal microscopy was used to analyze the cytosolic calcium mobilization induced by CNP. The phosphorylation of the residue Ser1177 of NOS was analyzed by Western blot and the expression and localization of NPR-C receptors was analyzed by immunohistochemistry. Key Findings CNP was less potent in inducing relaxation in denuded endothelium aortic rings than in intact ones. L-NAME attenuated the potency of CNP and similar results were obtained in the presence of hydroxocobalamin, an intracellular NO0 scavenger. CNP did not change the phosphorylation of Ser1177, the activation site of NOS-3, when compared with control. The addition of CNP produced an increase in [Ca2+]c in endothelial cells and a decrease in [Ca2+]c in vascular smooth muscle cells. The NPR-C-receptors are expressed in endothelial and adventitial rat aortas. Significance These results suggest that CNP-induced relaxation in intact aorta isolated from rats involves NO production due to [Ca2+]c increase in endothelial cells possibly through NPR-C activation expressed in these cells. The present study provides a breakthrough in the understanding of the close relationship between the vascular actions of nitric oxide and CNP. PMID:24787693

  11. Use of labeled tomato lectin for imaging vasculature structures.

    PubMed

    Robertson, Richard T; Levine, Samantha T; Haynes, Sherry M; Gutierrez, Paula; Baratta, Janie L; Tan, Zhiqun; Longmuir, Kenneth J

    2015-02-01

    Intravascular injections of fluorescent or biotinylated tomato lectin were tested to study labeling of vascular elements in laboratory mice. Injections of Lycopersicon esculentum agglutinin (tomato lectin) (50-100 µg/100 µl) were made intravascularly, through the tail vein, through a cannula implanted in the jugular vein, or directly into the left ventricle of the heart. Tissues cut for thin 10- to 12-µm cryostat sections, or thick 50- to 100-µm vibratome sections, were examined using fluorescence microscopy. Tissue labeled by biotinylated lectin was examined by bright field microscopy or electron microscopy after tissue processing for biotin. Intravascular injections of tomato lectin led to labeling of vascular structures in a variety of tissues, including brain, kidney, liver, intestine, spleen, skin, skeletal and cardiac muscle, and experimental tumors. Analyses of fluorescence in serum indicated the lectin was cleared from circulating blood within 2 min. Capillary labeling was apparent in tissues collected from animals within 1 min of intravascular injections, remained robust for about 1 h, and then declined markedly until difficult to detect 12 h after injection. Light microscopic images suggest the lectin bound to the endothelial cells that form capillaries and endothelial cells that line some larger vessels. Electron microscopic studies confirmed the labeling of luminal surfaces of endothelial cells. Vascular labeling by tomato lectin is compatible with a variety of other morphological labeling techniques, including histochemistry and immunocytochemistry, and thus appears to be a sensitive and useful method to reveal vascular patterns in relationship to other aspects of parenchymal development, structure, and function. PMID:25534591

  12. HGA-2, a novel galactoside-binding lectin from the sea cucumber Holothuria grisea binds to bacterial cells.

    PubMed

    de Melo, Arthur Alves; Carneiro, Rômulo Farias; de Melo Silva, Winnie; Moura, Raniere da Mata; Silva, Giselle Cristina; de Sousa, Oscarina Viana; de Sousa Saboya, Jefferson Pablo; Nascimento, Kyria Santiago do; Saker-Sampaio, Silvana; Nagano, Celso Shiniti; Cavada, Benildo Sousa; Sampaio, Alexandre Holanda

    2014-03-01

    A novel lectin, HGA-2, was isolated from the sea cucumber Holothuria grisea. The protein was isolated by a single chromatographic step using a column of Guar Gum as affinity. HGA-2 showed an apparent molecular mass of 17 kDa and 34 kDa under reducing and nonreducing conditions, respectively. The hemagglutinating activity was specific for rabbit erythrocytes, showing no activity for human blood A, B and O. Its hemagglutinating activity was inhibited by carbohydrates containing galactose, with higher affinity for GalNAc and glycoprotein porcine stomach mucin (PSM). HGA-2 was stable at pH 6-10, significantly declining at pH 5 and a temperature of 40°C, with its activity being abolished at 100 °C. The HGA-2 protein was found to be Ca(2+)-dependent; it was highly toxic against Artemia nauplii and able to recognize and agglutinate cells of Escherichia coli. Amino acid sequences of tryptic peptides of HGA-2 strongly suggest that HGA-2 is a member of the C-type lectin family. PMID:24393613

  13. Partial characterization of the lectin of runner beans (Phaseolus coccieneus) var. Alubia.

    PubMed

    Armienta-Aldana, Eduardo; Moreno-Legorreta, Manuel; Armienta-Aldana, Ernesto; Laguna-Granados, Sandra Viviana

    2009-03-01

    We extracted and partial characterized lectin from runner beans (Phaseolus coccineus L.). This lectin shows a great affinity to fetuin-agarose column like others lectins and the electrophoretic gels point one band of approximately 45 kDa. In addition to the previous assays, we detected the presence of lectins by agglutination assays. We know that lectins are non-enzymatic proteins or glycoproteins that bind carbohydrates. The biological function of plant lectins is not fully understood, but they are hypothesized to be involved in a number of intrinsic processes. Many of those processes include hemagglutination. We believe that the P. coocineus lectin will be an important tool for know the properties of many lectins, included their capacity to detected and quantify tumor markers.

  14. Tissue binding pattern of plant lectins in benign and malignant lesions of thyroid.

    PubMed

    Vijayakumar, T; Augustine, J; Mathew, L; Aleykutty, M A; Nair, M B; Remani, P; Nair, M K

    1992-01-01

    N-acetyl D-galactosamine specific lectins were isolated from the seeds of Jack Fruit (Artocarpus integrifolia) and Winged bean (Psophocarpus tetragonolobus) and D-galactose specific lectin was isolated from peanut (Arachis hypogaea). These lectins were conjugated to Horse Radish Peroxidase (HRP) and were used to study the lectin binding properties of benign and malignant lesions of the thyroid. For comparison of the results 10 normal fresh autopsy specimens were included in the study. The Peanut lectin (PNL) and Jack fruit lectin (JFL) conjugates showed positive binding with the cells in different lesions, while Winged Bean Lectin (WBL), despite its having a common inhibitory sugar, showed no binding even after neuraminidase treatment. These lectins revealed difference in the composition of glycoconjugates of benign and malignant thyroid cells. The HRP conjugated JFL and PNL may be of use in distinguishing carcinomatous tissues from benign tissues which makes them potential tools in the differential diagnosis of thyroid lesions.

  15. Lectin binding in the anterior segment of the bovine eye.

    PubMed

    Tuori, A; Virtanen, I; Uusitalo, H

    1994-10-01

    Eleven different fluorescent lectin-conjugates were used to reveal the location of carbohydrate residues in frozen sections of the anterior segment of bovine eyes. The lectins were specific for the following five major carbohydrate groups: (1) glucose/mannose group (Concanavalin A (Con A)); (2) N-acetylglucosamine group (wheat germ agglutinin (WGA)); (3) galactose/N-acetylgalactosamine group (Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA), Helix aspersa agglutinin (HAA), Psophocarpus tetragonolobus agglutinin (PTA), Griffonia simplicifolia agglutinin-I-B4 (GSA-I-B4), Artocarpus integrifolia agglutinin (JAC), peanut agglutinin (PNA) and Ricinus communis agglutinin (RCA-I)); (4) L-fucose group (Ulex europaeus agglutinin (UEA-I)); (5) sialic acid group (wheat germ agglutinin (WGA)). All the studied lectins except UEA-I reacted widely with different structures and the results suggest that there are distinct patterns of expression of carbohydrate residues in the anterior segment of the bovine eye. UEA-I bound only to epithelial structures. Some of the lectins reacted very intensely with apical cell surfaces of conjunctival and corneal epithelia suggesting a different glycosylation at the glycocalyx of the epithelia. Also, the binding patterns of conjunctival and corneal epithelia differed with some of the lectins: PNA and RCA-I did not bind at all, and GSA-I-B4 bound only very weakly to the epithelium of the cornea, whereas they bound to the epithelium of the conjunctiva. In addition, HPA, HAA, PNA and WGA did not bind to the corneal basement membrane, but bound to the conjunctiva and vascular basement membranes. This suggests that corneal basement membrane is somehow different from other basement membranes. Lectins with the same carbohydrate specificity (DBA, HPA, HAA and PTA) reacted with the sections almost identically, but some differences were noticed: DBA did not bind to the basement membrane of the conjunctiva and the sclera and did bind to

  16. Mannan-Binding Lectin in Cardiovascular Disease

    PubMed Central

    Cedzyński, Maciej

    2014-01-01

    Cardiovascular disease remains the leading cause of mortality and morbidity worldwide so research continues into underlying mechanisms. Since innate immunity and its potent component mannan-binding lectin have been proven to play an important role in the inflammatory response during infection and ischaemia-reperfusion injury, attention has been paid to its role in the development of cardiovascular complications as well. This review provides a general outline of the structure and genetic polymorphism of MBL and its role in inflammation/tissue injury with emphasis on associations with cardiovascular disease. MBL appears to be involved in the pathogenesis of atherosclerosis and, in consequence, coronary artery disease and also inflammation and tissue injury after myocardial infarction and heart transplantation. The relationship between MBL and disease is rather complex and depends on different genetic and environmental factors. That could be why the data obtained from animal and clinical studies are sometimes contradictory proving not for the first time that innate immunity is a “double-edge sword,” sometimes beneficial and, at other times disastrous for the host. PMID:24877121

  17. Lectin-like activity from Persea americana.

    PubMed

    Meade, N A; Staat, R H; Langley, S D; Doyle, R J

    1980-01-15

    An extract from the seeds of Persea americana possessed an erythro-agglutinating activity. The agglutinin was devoid of specificity for carbohydrates, but interacted readily with basic proteins or basic polyamino acids. The interaction between the agglutinin and egg-white lysozyme was not inhibited by chaotropic salts, but was sensitive to relatively low concentrations of urea. An affinity chromatographic procedure was developed in an effort to purify the agglutinin. Products from the chromatographic procedure were found not to contain higher specific agglutinating activities than the crude extract. Amino acid acid analyses of the extract showed the presence of relatively high proportions of glutamic and aspartic acids. In addition, the extract contained phosphorus and a visible chromophore. The agglutinin was resistant to detergents and denaturants, and proteases, nucleases, and other enzymes. The results suggest that, as opposed to other plant agglutinins, the active component from Persea is not a protein. Similarly, in contrast to many lectins, the agglutinin from Persea was not mitogenic for mouse lymphocytes. The agglutinin partially inhibited the mitogenesis of lymphocytes when the cells were treated with concanavalin A, or with bacterial lipopolysaccharide.

  18. Prevalence of the F-type lectin domain.

    PubMed

    Bishnoi, Ritika; Khatri, Indu; Subramanian, Srikrishna; Ramya, T N C

    2015-08-01

    F-type lectins are fucolectins with characteristic fucose and calcium-binding sequence motifs and a unique lectin fold (the "F-type" fold). F-type lectins are phylogenetically widespread with selective distribution. Several eukaryotic F-type lectins have been biochemically and structurally characterized, and the F-type lectin domain (FLD) has also been studied in the bacterial proteins, Streptococcus mitis lectinolysin and Streptococcus pneumoniae SP2159. However, there is little knowledge about the extent of occurrence of FLDs and their domain organization, especially, in bacteria. We have now mined the extensive genomic sequence information available in the public databases with sensitive sequence search techniques in order to exhaustively survey prokaryotic and eukaryotic FLDs. We report 437 FLD sequence clusters (clustered at 80% sequence identity) from eukaryotic, eubacterial and viral proteins. Domain architectures are diverse but mostly conserved in closely related organisms, and domain organizations of bacterial FLD-containing proteins are very different from their eukaryotic counterparts, suggesting unique specialization of FLDs to suit different requirements. Several atypical phylogenetic associations hint at lateral transfer. Among eukaryotes, we observe an expansion of FLDs in terms of occurrence and domain organization diversity in the taxa Mollusca, Hemichordata and Branchiostomi, perhaps coinciding with greater emphasis on innate immune strategies in these organisms. The naturally occurring FLDs with diverse domain organizations that we have identified here will be useful for future studies aimed at creating designer molecular platforms for directing desired biological activities to fucosylated glycoconjugates in target niches. PMID:25943580

  19. Prevalence of the F-type lectin domain.

    PubMed

    Bishnoi, Ritika; Khatri, Indu; Subramanian, Srikrishna; Ramya, T N C

    2015-08-01

    F-type lectins are fucolectins with characteristic fucose and calcium-binding sequence motifs and a unique lectin fold (the "F-type" fold). F-type lectins are phylogenetically widespread with selective distribution. Several eukaryotic F-type lectins have been biochemically and structurally characterized, and the F-type lectin domain (FLD) has also been studied in the bacterial proteins, Streptococcus mitis lectinolysin and Streptococcus pneumoniae SP2159. However, there is little knowledge about the extent of occurrence of FLDs and their domain organization, especially, in bacteria. We have now mined the extensive genomic sequence information available in the public databases with sensitive sequence search techniques in order to exhaustively survey prokaryotic and eukaryotic FLDs. We report 437 FLD sequence clusters (clustered at 80% sequence identity) from eukaryotic, eubacterial and viral proteins. Domain architectures are diverse but mostly conserved in closely related organisms, and domain organizations of bacterial FLD-containing proteins are very different from their eukaryotic counterparts, suggesting unique specialization of FLDs to suit different requirements. Several atypical phylogenetic associations hint at lateral transfer. Among eukaryotes, we observe an expansion of FLDs in terms of occurrence and domain organization diversity in the taxa Mollusca, Hemichordata and Branchiostomi, perhaps coinciding with greater emphasis on innate immune strategies in these organisms. The naturally occurring FLDs with diverse domain organizations that we have identified here will be useful for future studies aimed at creating designer molecular platforms for directing desired biological activities to fucosylated glycoconjugates in target niches.

  20. Identification of Lectins from Metastatic Cancer Cells through Magnetic Glyconanoparticles

    PubMed Central

    Kavunja, Herbert W.; Voss, Patricia G.

    2016-01-01

    Cancer cells can have characteristic carbohydrate binding properties. Previously, it was shown that a highly metastatic melanoma cell line B16F10 bound to galacto-side-functionalized nanoparticles much stronger than the corresponding less metastatic B16F1 cells. To better understand the carbohydrate binding properties of cancer cells, herein, we report the isolation and characterization of endogenous galactose binding proteins from B16F10 cells using magnetic glyconanoparticles. The galactose-coated magnetic glyconanoparticles could bind with lectins present in the cells and be isolated through magnet-mediated separation. Through Western blot and mass spectrometry, the arginine/serine rich splicing factor Sfrs1 was identified as a galactose-selective endogenous lectin, overexpressed in B16F10 cells, compared with B16F1 cells. In addition, galactin-3 was found in higher amounts in B16F10 cells. Finally, the glyconanoparticles exhibited a superior efficiency in lectin isolation, from both protein mixtures and live cells, than the corresponding more traditional microparticles functionalized with carbohydrates. Thus, the magnetic glyconanoparticles present a useful tool for discovery of endogenous lectins, as well as binding partners of lectins, without prior knowledge of protein identities. PMID:27110035

  1. K⁺ channel gating: C-type inactivation is enhanced by calcium or lanthanum outside.

    PubMed

    Armstrong, Clay M; Hoshi, Toshinori

    2014-09-01

    Many voltage-gated K(+) channels exhibit C-type inactivation. This typically slow process has been hypothesized to result from dilation of the outer-most ring of the carbonyls in the selectivity filter, destroying this ring's ability to bind K(+) with high affinity. We report here strong enhancement of C-type inactivation upon extracellular addition of 10-40 mM Ca(2+) or 5-50 µM La(3+). These multivalent cations mildly increase the rate of C-type inactivation during depolarization and markedly promote inactivation and/or suppress recovery when membrane voltage (V(m)) is at resting levels (-80 to -100 mV). At -80 mV with 40 mM Ca(2+) and 0 mM K(+) externally, ShBΔN channels with the mutation T449A inactivate almost completely within 2 min or less with no pulsing. This behavior is observed only in those mutants that show C-type inactivation on depolarization and is distinct from the effects of Ca(2+) and La(3+) on activation (opening and closing of the V(m)-controlled gate), i.e., slower activation of K(+) channels and a positive shift of the mid-voltage of activation. The Ca(2+)/La(3+) effects on C-type inactivation are antagonized by extracellular K(+) in the low millimolar range. This, together with the known ability of Ca(2+) and La(3+) to block inward current through K(+) channels at negative voltage, strongly suggests that Ca(2+)/La(3+) acts at the outer mouth of the selectivity filter. We propose that at -80 mV, Ca(2+) or La(3+) ions compete effectively with K(+) at the channel's outer mouth and prevent K(+) from stabilizing the filter's outer carbonyl ring.

  2. Functional environmental proteomics: elucidating the role of a c-type cytochrome abundant during uranium bioremediation.

    PubMed

    Yun, Jiae; Malvankar, Nikhil S; Ueki, Toshiyuki; Lovley, Derek R

    2016-02-01

    Studies with pure cultures of dissimilatory metal-reducing microorganisms have demonstrated that outer-surface c-type cytochromes are important electron transfer agents for the reduction of metals, but previous environmental proteomic studies have typically not recovered cytochrome sequences from subsurface environments in which metal reduction is important. Gel-separation, heme-staining and mass spectrometry of proteins in groundwater from in situ uranium bioremediation experiments identified a putative c-type cytochrome, designated Geobacter subsurface c-type cytochrome A (GscA), encoded within the genome of strain M18, a Geobacter isolate previously recovered from the site. Homologs of GscA were identified in the genomes of other Geobacter isolates in the phylogenetic cluster known as subsurface clade 1, which predominates in a diversity of Fe(III)-reducing subsurface environments. Most of the gscA sequences recovered from groundwater genomic DNA clustered in a tight phylogenetic group closely related to strain M18. GscA was most abundant in groundwater samples in which Geobacter sp. predominated. Expression of gscA in a strain of Geobacter sulfurreducens that lacked the gene for the c-type cytochrome OmcS, thought to facilitate electron transfer from conductive pili to Fe(III) oxide, restored the capacity for Fe(III) oxide reduction. Atomic force microscopy provided evidence that GscA was associated with the pili. These results demonstrate that a c-type cytochrome with an apparent function similar to that of OmcS is abundant when Geobacter sp. are abundant in the subsurface, providing insight into the mechanisms for the growth of subsurface Geobacter sp. on Fe(III) oxide and suggesting an approach for functional analysis of other Geobacter proteins found in the subsurface.

  3. Cloning and characterization of a monocot mannose-binding lectin from Crocus vernus (family Iridaceae).

    PubMed

    Van Damme, E J; Astoul, C H; Barre, A; Rougé, P; Peumans, W J

    2000-08-01

    The molecular structure and carbohydrate-binding activity of the lectin from bulbs of spring crocus (Crocus vernus) has been determined unambiguously using a combination of protein analysis and cDNA cloning. Molecular cloning revealed that the lectin called C. vernus agglutinin (CVA) is encoded by a precursor consisting of two tandemly arrayed lectin domains with a reasonable sequence similarity to the monocot mannose-binding lectins. Post-translational cleavage of the precursor yields two equally sized polypeptides. Mature CVA consists of two pairs of polypeptides and hence is a heterotetrameric protein. Surface plasmon resonance studies of the interaction of the crocus lectin with high mannose-type glycans showed that the lectin interacts specifically with exposed alpha-1,3-dimannosyl motifs. Molecular modelling studies confirmed further the close relationships in overall fold and three-dimensional structure of the mannose-binding sites of the crocus lectin and other monocot mannose-binding lectins. However, docking experiments indicate that only one of the six putative mannose-binding sites of the CVA protomer is active. These results can explain the weak carbohydrate-binding activity and low specific agglutination activity of the lectin. As the cloning and characterization of the spring crocus lectin demonstrate that the monocot mannose-binding lectins occur also within the family Iridaceae a refined model of the molecular evolution of this lectin family is proposed.

  4. Bi- to tetravalent glycoclusters presenting GlcNAc/GalNAc as inhibitors: from plant agglutinins to human macrophage galactose-type lectin (CD301) and galectins.

    PubMed

    André, Sabine; O'Sullivan, Shane; Koller, Christiane; Murphy, Paul V; Gabius, Hans-Joachim

    2015-04-14

    Emerging insights into the functional spectrum of tissue lectins leads to identification of new targets for the custom-made design of potent inhibitors, providing a challenge for synthetic chemistry. The affinity and selectivity of a carbohydrate ligand for a lectin may immensely be increased by a number of approaches, which includes varying geometrical or topological features. This perspective leads to the design and synthesis of glycoclusters and their testing using assays of physiological relevance. Herein, hydroquinone, resorcinol, benzene-1,3,5-triol and tetra(4-hydroxyphenyl)ethene have been employed as scaffolds and propargyl derivatives obtained. The triazole-containing linker to the α/β-O/S-glycosides of GlcNAc/GalNAc presented on these scaffolds was generated by copper-catalysed azide-alkyne cycloaddition. This strategy was used to give a panel of nine glycoclusters with bi-, tri- and tetravalency. Maintained activity for lectin binding after conjugation was ascertained for both sugars in solid-phase assays with the plant agglutinins WGA (GlcNAc) and DBA (GalNAc). Absence of cross-reactivity excluded any carbohydrate-independent reactivity of the bivalent compounds, allowing us to proceed to further testing with a biomedically relevant lectin specific for GalNAc. Macrophage galactose(-binding C)-type lectin, involved in immune defence by dendritic cells and in virus uptake, was produced as a soluble protein without/with its α-helical coiled-coil stalk region. Binding to ligands presented on a matrix and on cell surfaces was highly susceptible to the presence of the tetravalent inhibitor derived from the tetraphenylethene-containing scaffold, and presentation of GalNAc with an α-thioglycosidic linkage proved favorable. Cross-reactivity of this glycocluster to human galectins-3 and -4, which interact with Tn-antigen-presenting mucins, was rather small. Evidently, the valency and spatial display of α-GalNAc residues is a key factor to design potent and

  5. Bi- to tetravalent glycoclusters presenting GlcNAc/GalNAc as inhibitors: from plant agglutinins to human macrophage galactose-type lectin (CD301) and galectins.

    PubMed

    André, Sabine; O'Sullivan, Shane; Koller, Christiane; Murphy, Paul V; Gabius, Hans-Joachim

    2015-04-14

    Emerging insights into the functional spectrum of tissue lectins leads to identification of new targets for the custom-made design of potent inhibitors, providing a challenge for synthetic chemistry. The affinity and selectivity of a carbohydrate ligand for a lectin may immensely be increased by a number of approaches, which includes varying geometrical or topological features. This perspective leads to the design and synthesis of glycoclusters and their testing using assays of physiological relevance. Herein, hydroquinone, resorcinol, benzene-1,3,5-triol and tetra(4-hydroxyphenyl)ethene have been employed as scaffolds and propargyl derivatives obtained. The triazole-containing linker to the α/β-O/S-glycosides of GlcNAc/GalNAc presented on these scaffolds was generated by copper-catalysed azide-alkyne cycloaddition. This strategy was used to give a panel of nine glycoclusters with bi-, tri- and tetravalency. Maintained activity for lectin binding after conjugation was ascertained for both sugars in solid-phase assays with the plant agglutinins WGA (GlcNAc) and DBA (GalNAc). Absence of cross-reactivity excluded any carbohydrate-independent reactivity of the bivalent compounds, allowing us to proceed to further testing with a biomedically relevant lectin specific for GalNAc. Macrophage galactose(-binding C)-type lectin, involved in immune defence by dendritic cells and in virus uptake, was produced as a soluble protein without/with its α-helical coiled-coil stalk region. Binding to ligands presented on a matrix and on cell surfaces was highly susceptible to the presence of the tetravalent inhibitor derived from the tetraphenylethene-containing scaffold, and presentation of GalNAc with an α-thioglycosidic linkage proved favorable. Cross-reactivity of this glycocluster to human galectins-3 and -4, which interact with Tn-antigen-presenting mucins, was rather small. Evidently, the valency and spatial display of α-GalNAc residues is a key factor to design potent and

  6. BSA-boronic acid conjugate as lectin mimetics.

    PubMed

    Narla, Satya Nandana; Pinnamaneni, Poornima; Nie, Huan; Li, Yu; Sun, Xue-Long

    2014-01-10

    We report bovine serum albumin (BSA)-boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA-BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS-PAGE gel. The BSA-BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA-BA conjugates was conducted by immobilizing BSA-BA onto SPR gold chip. Overall, we demonstrated a BSA-BA-based lectin mimetics for glyco-capturing applications. These lectin mimetics are expected to provide an important tool for glycomics and biosensor research and applications.

  7. Isolation and biochemical characterization of Apios tuber lectin.

    PubMed

    Kenmochi, Eri; Kabir, Syed Rashel; Ogawa, Tomohisa; Naude, Ryno; Tateno, Hiroaki; Hirabayashi, Jun; Muramoto, Koji

    2015-01-09

    Apios tuber lectin, named ATL, was isolated from Apios americana Medikus by two chromatography steps, hydrophobic chromatography and anion-exchange chromatography. The minimum concentration required for the hemagglutination activity toward rabbit erythrocytes of ATL was 4 μg/mL. ATL was composed of a homodimer of 28.4 kDa subunits. The amino acid sequence of ATL was similar to those of other legume lectins. The lectin showed moderate stability toward heating and acidic pH, and the binding affinity against several monosaccharides, such as D-glucosamine and D-galactosamine. ATL also bound to desialylated or agalactosylated glycoproteins such as asialo and agalacto transferrin. ATL decreased the transepithelial electrical resistance across human intestinal Caco-2 cell monolayers, suggesting the effect on the tight junction-mediated paracellular transport.

  8. Production and purification of active snowdrop lectin in Escherichia coli.

    PubMed

    Longstaff, M; Powell, K S; Gatehouse, J A; Raemaekers, R; Newell, C A; Hamilton, W D

    1998-02-15

    Recombinant snowdrop lectin was produced in Escherichia coli from a cDNA clone encoding mature Galanthus nivalis agglutinin. After induction with isopropylthio-beta-D-galactoside, inclusion bodies from E. coli were solubilised and the G. nivalis agglutinin purified by metal-affinity chromatography using a carboxy-terminal hexahistidine tag. The protein was refolded on the metal-affinity column prior to elution. After purification, the recombinant G. nivalis agglutinin agglutinated rabbit erythrocytes to a dilution similar to that determined for 'native' lectin purified from snowdrop, and showed similar specific binding to mannose. The toxicity of the recombinant G. nivalis agglutinin towards rice brown planthopper (Nilaparvata lugens) was shown to be similar to that of 'native' G. nivalis agglutinin when incorporated into an artificial diet. The recombinant G. nivalis agglutinin is thus functionally similar to 'native' snowdrop lectin.

  9. Isolation and biochemical characterization of Apios tuber lectin.

    PubMed

    Kenmochi, Eri; Kabir, Syed Rashel; Ogawa, Tomohisa; Naude, Ryno; Tateno, Hiroaki; Hirabayashi, Jun; Muramoto, Koji

    2015-01-01

    Apios tuber lectin, named ATL, was isolated from Apios americana Medikus by two chromatography steps, hydrophobic chromatography and anion-exchange chromatography. The minimum concentration required for the hemagglutination activity toward rabbit erythrocytes of ATL was 4 μg/mL. ATL was composed of a homodimer of 28.4 kDa subunits. The amino acid sequence of ATL was similar to those of other legume lectins. The lectin showed moderate stability toward heating and acidic pH, and the binding affinity against several monosaccharides, such as D-glucosamine and D-galactosamine. ATL also bound to desialylated or agalactosylated glycoproteins such as asialo and agalacto transferrin. ATL decreased the transepithelial electrical resistance across human intestinal Caco-2 cell monolayers, suggesting the effect on the tight junction-mediated paracellular transport. PMID:25584830

  10. Evaluating the Thickness of Multivalent Glycopolymer Brushes for Lectin Binding.

    PubMed

    Lazar, Jaroslav; Park, Hyunji; Rosencrantz, Ruben R; Böker, Alexander; Elling, Lothar; Schnakenberg, Uwe

    2015-08-01

    Electrochemical impedance spectroscopy (EIS) is applied for investigating binding of lectins to multivalent glycopolymer brushes grafted from interdigital gold microelectrodes. By variation of the measuring frequency, EIS allows simultaneous analysis of binding at different subnanometer distances from the sensor surfaces. In this way, the binding dynamics along the brushes are quantified, giving an idea about the motion of the lectin through the brush layer. Two different brush lengths are investigated, revealing distinct dynamics of lectin binding due to changing topology of the brushes. Moreover, very low K D values in the nanomolar range are obtained. This unique platform may be used as sophisticated biosensor for detailed investigation of high-affinity protein binding to poly-mer layers. PMID:26096302

  11. Cell surface lectin-binding glycoconjugates on marine planktonic protists.

    PubMed

    Roberts, Emily C; Zubkov, Mikhail V; Martin-Cereceda, Mercedes; Novarino, Gianfranco; Wootton, Emma C

    2006-12-01

    Carbohydrate-protein interactions appear to play an important role in the phagocytosis of microbial prey by free-living protozoa. The present study utilizes FITC-labelled plant lectins to investigate the presence and localization of cell surface glycoconjugates on live and fixed planktonic protists (Dunaliella primolecta, Oxyrrhis marina, Goniomonas amphinema, Paraphysomonas vestita and Euplotes vannus). With live flagellate preparations, lectins primarily bound to external cell surfaces, with minimal internal staining observed. In contrast, cell fixation permeabilized cell membranes, allowing lectins to bind to internal structures, such as nuclear membranes and food vacuoles, interfering with the characterization of cell surface glycoconjugates. The method developed to label cell surface sugar moieties of live planktonic protists successfully overcomes the problems associated with fixation, and thus provides a useful protocol for future studies on protistan cell surface carbohydrate characterization.

  12. The calcitonin receptor on T 47D breast cancer cells. Evidence for glycosylation.

    PubMed Central

    Moseley, J M; Findlay, D M; Gorman, J J; Michelangeli, V P; Martin, T J

    1983-01-01

    The glycosyl nature of the receptor for the peptide hormone calcitonin has been investigated in a human breast cancer cell line, T 47D. Studies have been carried out to assess the ability of various lectins and of the antibiotic tunicamycin to inhibit specific binding of calcitonin to the cells, to reduce cross-linking of photoactive calcitonin to a macromolecular receptor component and to influence calcitonin stimulation of cyclic AMP. Pre-incubation of cells with low concentrations of tunicamycin for 72 h resulted in a reduction of total specific binding by approx. 80% and a 40% reduction in calcitonin-stimulated adenylate cyclase; formation of the cross-linked receptor component was also inhibited. Wheat-germ lectin showed the most marked inhibition of total specific binding and cyclic AMP production. However, cross-linking of photoactive calcitonin to receptor component was totally inhibited by this lectin. Soya-bean lectin brought about very little reduction in total specific binding but had more profound effects on calcitonin-stimulated cyclic AMP production and cross-linking of photoactive calcitonin. Concanavalin A and lentil lectin showed some inhibition of all parameters. The data indicate that the calcitonin receptor in T 47D cells is associated with glycosyl moieties, the major contributors of which are N-acetyl-D-glucosamine residues, but N-acetyl-D-galactosamine and mannose residues are also associated. PMID:6309149

  13. Agrarian diet and diseases of affluence – Do evolutionary novel dietary lectins cause leptin resistance?

    PubMed Central

    Jönsson, Tommy; Olsson, Stefan; Ahrén, Bo; Bøg-Hansen, Thorkild C; Dole, Anita; Lindeberg, Staffan

    2005-01-01

    Background The global pattern of varying prevalence of diseases of affluence, such as obesity, cardiovascular disease and diabetes, suggests that some environmental factor specific to agrarian societies could initiate these diseases. Presentation of the hypothesis We propose that a cereal-based diet could be such an environmental factor. Through previous studies in archaeology and molecular evolution we conclude that humans and the human leptin system are not specifically adapted to a cereal-based diet, and that leptin resistance associated with diseases of affluence could be a sign of insufficient adaptation to such a diet. We further propose lectins as a cereal constituent with sufficient properties to cause leptin resistance, either through effects on metabolism central to the proper functions of the leptin system, and/or directly through binding to human leptin or human leptin receptor, thereby affecting the function. Testing the hypothesis Dietary interventions should compare effects of agrarian and non-agrarian diets on incidence of diseases of affluence, related risk factors and leptin resistance. A non-significant (p = 0.10) increase of cardiovascular mortality was noted in patients advised to eat more whole-grain cereals. Our lab conducted a study on 24 domestic pigs in which a cereal-free hunter-gatherer diet promoted significantly higher insulin sensitivity, lower diastolic blood pressure and lower C-reactive protein as compared to a cereal-based swine feed. Testing should also evaluate the effects of grass lectins on the leptin system in vivo by diet interventions, and in vitro in various leptin and leptin receptor models. Our group currently conducts such studies. Implications of the hypothesis If an agrarian diet initiates diseases of affluence it should be possible to identify the responsible constituents and modify or remove them so as to make an agrarian diet healthier. PMID:16336696

  14. Effect of lectins from Diocleinae subtribe against oral Streptococci.

    PubMed

    Cavalcante, Theodora Thays Arruda; Anderson Matias da Rocha, Bruno; Alves Carneiro, Victor; Vassiliepe Sousa Arruda, Francisco; Fernandes do Nascimento, Antônia Sâmia; Cardoso Sá, Nairley; do Nascimento, Kyria Santiago; Sousa Cavada, Benildo; Holanda Teixeira, Edson

    2011-01-01

    Surface colonization is an essential step in biofilm development. The ability of oral pathogens to adhere to tooth surfaces is directly linked with the presence of specific molecules at the bacterial surface that can interact with enamel acquired pellicle ligands. In light of this, the aim of this study was to verify inhibitory and antibiofilm action of lectins from the Diocleinaesubtribe against Streptococcus mutans and Streptococcus oralis. The inhibitory action against planctonic cells was assessed using lectins from Canavaliaensi formis (ConA), Canavalia brasiliensis (ConBr), Canavalia maritima (ConM), Canavalia gladiata (CGL) and Canavalia boliviana (ConBol). ConBol, ConBr and ConM showed inhibitory activity on S. mutans growth. All lectins, except ConA, stimulated significantly the growth of S. oralis. To evaluate the effect on biofilm formation, clarified saliva was added to 96-well, flat-bottomed polystyrene plates, followed by the addition of solutions containing 100 or 200 µg/mL of the selected lectins. ConBol, ConM and ConA inhibited the S. mutans biofilms. No effects were found on S. oralis biofilms. Structure/function analysis were carried out using bioinformatics tools. The aperture and deepness of the CRD (Carbohydrate Recognition Domain) permit us to distinguish the two groups of Canavalia lectins in accordance to their actions against S. mutans and S. oralis. The results found provide a basis for encouraging the use of plant lectins as biotechnological tools in ecological control and prevention of caries disease. PMID:21525793

  15. Purification of a thermostable antinociceptive lectin isolated from Andira anthelmia.

    PubMed

    Nascimento, Kyria Santiago; Nascimento, Francisco Lucas Faustino do; Silva, Mayara Torquato Lima; Nobre, Camila Bezerra; Moreira, Cleane Gomes; Brizeno, Luiz André Cavalcante; da Ponte, Edson Lopes; Assreuy, Ana Maria Sampaio; Cavada, Benildo Sousa

    2016-06-01

    Andira anthelmia (tribe Dalbergieae), a plant from Brazilian Amazon, possesses a seed lectin that was purified by affinity chromatography in sepharose-mannose. This novel Dalbergieae lectin, named AAL, agglutinated rabbit erythrocytes treated with trypsin. The hemagglutinating activity of AAL was maintained after incubation at a wide range of temperature (40 to 70 °C) and pH, was shown to be dependent on divalent cations, and was inhibited by d-mannose and d-sucrose. AAL showed an electrophoretic profile in sodium dodecyl sulfate-polyacrylamide gel electrophoresis similar to other lectins of the tribe Dalbergieae, presenting a double band of molecular weight with approximately 20 kDa and other minor bands of 17, 15, and 13 kDa, being the smaller fragment glycosylated. AAL injected by intravenous route in mice showed antinociceptive activity in two behavioral tests (writhing and formalin). In the writhing test induced by acetic acid, AAL showed inhibitory effect at 0.01 mg/kg (68%), 0.1 mg/kg (46%) and 1 mg/kg (74%). In the formalin test, AAL (0.1 mg/kg) inhibited by 48% the licking time in the inflammatory phase, an effect that was recovered by the lectin association with mannose. In conclusion, AAL presents analgesic effect involving the lectin domain via peripheral mechanisms of inflammatory nociception. This activity highlights the importance of lectins as tools to be used for understanding the interaction of protein-carbohydrate in processes associated to inflammatory pain. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26638121

  16. Erythrina lectins detect the H/HI blood groups.

    PubMed

    Sudakevitz, D; Gilboa-Garber, N; Levene, C; Sela, R; Bhattacharyya, L

    1991-08-01

    The lectin purified from Erythrina corallodendron seeds which binds N-acetyllactosamine greater than N-acetyl-D-galactosamine greater than alpha and beta galactosides greater than D-galactose was examined for its ABO(H) blood group specificity. It has been shown that this lectin causes the strongest hemagglutination of O(H) and weakest of Oh(Bombay) red blood cells, and interacts with the H antigen in association with the I antigen. The reactions of Erythrina corallodendron and Erythrina indica lectins (which are similar in sugar specificity) with erythrocytes of different ABO(H) and Ii blood groups (the I bloods were all from adults and the i from either cord or adult bloods) revealed the following order of activity: O(H)I greater than A2 I greater than O(H)i adult greater than A2BI greater than BI greater than O(H)i cord greater than A1I greater than A1i adult greater than Bi cord greater than A1BI greater than Ai cord greater than ABi cord greater than OhI. The Erythrina indica lectin showed a lower differentiation between the agglutination of O(H) and Oh erythrocytes. Both Erythrina lectins exhibited H/HI blood group preference but were not inhibited by the saliva from ABO(H) "secretors". Thus they may be classified with the Cytisus sessilifolius, Lotus tetragonolobus and Laburnum alpinum lectins which are inhibited by lactose but not by H blood group substances in secretions.

  17. Purification of a thermostable antinociceptive lectin isolated from Andira anthelmia.

    PubMed

    Nascimento, Kyria Santiago; Nascimento, Francisco Lucas Faustino do; Silva, Mayara Torquato Lima; Nobre, Camila Bezerra; Moreira, Cleane Gomes; Brizeno, Luiz André Cavalcante; da Ponte, Edson Lopes; Assreuy, Ana Maria Sampaio; Cavada, Benildo Sousa

    2016-06-01

    Andira anthelmia (tribe Dalbergieae), a plant from Brazilian Amazon, possesses a seed lectin that was purified by affinity chromatography in sepharose-mannose. This novel Dalbergieae lectin, named AAL, agglutinated rabbit erythrocytes treated with trypsin. The hemagglutinating activity of AAL was maintained after incubation at a wide range of temperature (40 to 70 °C) and pH, was shown to be dependent on divalent cations, and was inhibited by d-mannose and d-sucrose. AAL showed an electrophoretic profile in sodium dodecyl sulfate-polyacrylamide gel electrophoresis similar to other lectins of the tribe Dalbergieae, presenting a double band of molecular weight with approximately 20 kDa and other minor bands of 17, 15, and 13 kDa, being the smaller fragment glycosylated. AAL injected by intravenous route in mice showed antinociceptive activity in two behavioral tests (writhing and formalin). In the writhing test induced by acetic acid, AAL showed inhibitory effect at 0.01 mg/kg (68%), 0.1 mg/kg (46%) and 1 mg/kg (74%). In the formalin test, AAL (0.1 mg/kg) inhibited by 48% the licking time in the inflammatory phase, an effect that was recovered by the lectin association with mannose. In conclusion, AAL presents analgesic effect involving the lectin domain via peripheral mechanisms of inflammatory nociception. This activity highlights the importance of lectins as tools to be used for understanding the interaction of protein-carbohydrate in processes associated to inflammatory pain. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Electrochemical potential of Microgramma vaccinifolia rhizome lectin.

    PubMed

    Santana, Giselly Maria de Sá; Albuquerque, Lidiane Pereira de; Napoleão, Thiago Henrique; Souza, Sandra Rodrigues de; Coelho, Luana Cassandra Breitenbach Barroso; Paiva, Patrícia Maria Guedes

    2012-06-01

    This work reports the isolation of Microgramma vaccinifolia rhizome lectin (MvRL) and the determination of electrochemical potentials of MvRL in the presence of Ca²⁺, Mg²⁺ and human type O erythrocytes. MvRL showed the highest specific hemagglutinating activity with human type O erythrocytes and showed a single polypeptide band of 17 kDa on SDS-PAGE. MvRL hemagglutinating activity was neutralized after dialysis with EDTA, and addition of Ca²⁺ and Mg²⁺ restored the activity. Electrochemical potentials of MvRL in the presence of 100 mM Ca²⁺ (882 mV) and 60 mM Mg²⁺ (1051 mV) were higher (p<0.05) than in the presence of only 0.15 M NaCl (247 mV), indicating that the electrochemical system was sensitive to structural and physico-chemical changes promoted by these ions. MvRL potential did not change in the presence of type O erythrocytes. The electrochemical system was able to detect changes in electrochemical potentials of MvRL promoted by Ca²⁺ and Mg²⁺, even in a complex environment (human serum supplemented with 40 and 60mM of these ions). The study reveals that the stimulatory effect of Ca²⁺ and Mg²⁺ on hemagglutinating activity may be linked to conformational change and/or alterations in surface charge distribution of MvRL. PMID:22197266

  19. Neutrophil haptotaxis induced by the lectin KM+.

    PubMed

    Ganiko, L; Martins, A R; Espreáfico, E M; Roque-Barreira, M C

    1998-05-01

    KM+ is a D-mannose binding lectin from Artocarpus integrifolia that induces neutrophil migration in vitro and in vivo. This attractant activity was shown to be caused by haptotaxis rather than chemotaxis. The inhibition by D-mannose of the neutrophil attraction exerted by KM+, both in vitro and in vivo, supports the idea that haptotaxis is triggered in vivo by the sugar binding sites interacting with glycoconjugates located on the neutrophil surface and in the extracellular matrix. In the present study an in vivo haptotaxis assay was performed by intradermally (i.d.) injecting 125I-KM+ (200 ng), which led to a selective staining of loose connective tissue and vascular endothelium. The radiolabelled area exhibited a maximum increase (five-fold) in neutrophil infiltration 3 h after injection, relative to i.d. 200 ng 125I-BSA. We characterized the ex vivo binding of KM+ to tissue elements by immunohistochemistry, using paraformaldehyde-fixed, paraffin-embedded, untreated rat skin. Bound KM+ was detected with an affinity-purified rabbit IgG anti-KM+ and visualized with an alkaline phosphatase based system. KM+ binding to connective tissue and vascular endothelium was inhibited by preincubating KM+ with 0.4 mM D-mannose and was potentiated by heparan sulfate (100 microg ml(-1)). An in vitro assay carried out in a Boyden microchamber showed that heparan sulfate potentiated the attractant effect of 10 microg KM+ by 34%. The present data suggest that KM+ induces neutrophil migration in vivo by haptotaxis and that the haptotactic gradient could be provided by the interaction of the KM+ carbohydrate recognition site(s) with mannose-containing glycoconjugate(s) in vascular endothelium and connective tissue. Heparan sulfate would act as an accessory molecule, enhancing the KM+ tissue binding and potentiating the induced neutrophil haptotaxis.

  20. Soluble Host Defense Lectins in Innate Immunity to Influenza Virus

    PubMed Central

    Ng, Wy Ching; Tate, Michelle D.; Brooks, Andrew G.; Reading, Patrick C.

    2012-01-01

    Host defenses against viral infections depend on a complex interplay of innate (nonspecific) and adaptive (specific) components. In the early stages of infection, innate mechanisms represent the main line of host defense, acting to limit the spread of virus in host tissues prior to the induction of the adaptive immune response. Serum and lung fluids contain a range of lectins capable of recognizing and destroying influenza A viruses (IAV). Herein, we review the mechanisms by which soluble endogenous lectins mediate anti-IAV activity, including their role in modulating IAV-induced inflammation and disease and their potential as prophylactic and/or therapeutic treatments during severe IAV-induced disease. PMID:22665991

  1. Lectin binding and surface glycoprotein pattern of human macrophage populations.

    PubMed

    Kreipe, H; Radzun, H J; Schumacher, U; Parwaresch, M R

    1986-01-01

    In the present study unstimulated and stimulated human blood monocytes, untreated and phorbol ester treated U-937 cells, as well as human peritoneal and alveolar macrophages were studied with respect to their surface membrane properties. Binding of different lectins and electrophoretic patterns of tritium labeled surface glycoproteins were compared. The analysis of surface glycoproteins could be interpreted as evidence for a common origin of the analysed cell populations. Furthermore, banding patterns of glycoproteins might be useful to define certain activation states within monocyte/macrophage differentiation. In contrast, lectin binding pattern did not clearly discriminate macrophage subpopulations. PMID:3102412

  2. Structural and functional similarities of breadfruit seed lectin and jacalin.

    PubMed

    Pineau, N; Pousset, J L; Preud'Homme, J L; Aucouturier, P

    1990-03-01

    Aquous extracts from seeds of Artocarpus altilis (breadfruit) and Artocarpus heterophyllus (jackfruit) were compared by polyacrylamide gel electrophoresis. Two bands of the same size (12 and 15 kD) as the jacalin subunits were the major components in breadfruit seed extract. They strongly reacted with anti-jacalin antibodies by western blotting. The breadfruit lectin displayed the same IgAl and IgD precipitation specificity as jacalin in gel double diffusion experiments. It also stimulated in vitro proliferation of human peripheral blood mononuclear cells. These results suggest that lectins from both species of Artocarpus are very similar.

  3. Dietary homocysteine promotes atherosclerosis in apoE-deficient mice by inducing scavenger receptors expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated plasma homocysteine (Hcy) levels have been recognized as an independent risk factor for cardiovascular and cerebrovascular diseases. However, the causative mechanisms have not been delineated. Scavenger receptors such as scavenger receptor-AI/II (SR-A), CD36, and lectin-like oxidized LDL ...

  4. C-type natriuretic peptide inhibits leukocyte recruitment and platelet-leukocyte interactions via suppression of P-selectin expression

    NASA Astrophysics Data System (ADS)

    Scotland, Ramona S.; Cohen, Marc; Foster, Paul; Lovell, Matthew; Mathur, Anthony; Ahluwalia, Amrita; Hobbs, Adrian J.

    2005-10-01

    The multifaceted process of immune cell recruitment to sites of tissue injury is key to the development of an inflammatory response and involved in the pathogenesis of numerous cardiovascular disorders. We recently identified C-type natriuretic peptide (CNP) as an important endothelium-derived mediator that regulates vascular tone and protects against myocardial ischemia/reperfusion injury. Herein, we investigated whether CNP inhibits leukocyte recruitment and platelet aggregation and thereby exerts a potential antiinflammatory influence on the blood vessel wall. We assessed the effects of CNP on leukocyte-endothelial cell interactions in mouse mesenteric postcapillary venules in vivo in animals with high basal leukocyte activation (endothelial nitric oxide synthase knockout mice, eNOS-/-) or under acute inflammatory conditions (induced by interleukin-1 or histamine). CNP suppressed basal leukocyte rolling in eNOS-/- mice in a rapid, reversible, and concentration-dependent manner. These effects of CNP were mimicked by the selective natriuretic peptide receptor-C agonist cANF4-23. CNP also suppressed leukocyte rolling induced by IL-1 or histamine, inhibited platelet-leukocyte interactions, and prevented thrombin-induced platelet aggregation of human blood. Furthermore, analysis of human umbilical vein endothelial cells, leukocytes, and platelets revealed that CNP selectively attenuates expression of P-selectin. Thus, CNP is a modulator of acute inflammation in the blood vessel wall characterized by leukocyte and platelet activation. These antiinflammatory effects appear to be mediated, at least in part, via suppression of P-selectin expression. These observations suggest that endothelial CNP might maintain an anti-atherogenic influence on the blood vessel wall and represent a target for therapeutic intervention in inflammatory cardiovascular disorders. endothelium | natriuretic peptide receptor type C | atherosclerosis | thrombosis

  5. Lectin extracts of champedak seeds demonstrate selective stimulation of T lymphocyte proliferation.

    PubMed

    Hashim, O H; Gendeh, G S; Jaafar, M I

    1992-06-01

    The effect of extracts of champedak (Artocarpus integer) seed lectin on the proliferation of normal human lymphocyte was investigated. The IgA1 binding lectin was demonstrated to stimulate the proliferation of human peripheral blood mononuclear cells. Action of the lectin on enriched T and B cell populations demonstrated T lymphocyte specificity. The lectin was not mitogenic to B lymphocytes. Optimal stimulation of proliferative response was achieved when cells were subjected to 5 days exposure to the crude lectin at 20 micrograms/ml.

  6. Spin-glass transition in Ni carbide single crystal nanoparticles with Ni3C - type structure

    NASA Astrophysics Data System (ADS)

    Fujieda, S.; Kuboniwa, T.; Shinoda, K.; Suzuki, S.; Echigoya, J.

    2016-05-01

    Hexagonal shaped nanoparticles about 60 nm in size were successfully synthesized in tetraethylene glycol solution containing polyvinylpyrrolidone. By the analysis of the electron diffraction pattern, these were identified as a single crystal of Ni carbide with Ni3C - type structure. Their magnetization curve at 5 K was not completely saturated under a magnetic field of 5 T. The thermomagnetization curves after zero-field cooling and after field cooling exhibited the magnetic cooling effect at low temperatures. Furthermore, the 2nd order nonlinear term of AC magnetic susceptibility exhibited a negative divergence at about 17 K. It is concluded that Ni carbide single crystal nanoparticles with the Ni3C - type structure exhibit spin-glass transition at low temperatures.

  7. Development of an in vitro infectivity assay for the C-type bovine leukemia virus.

    PubMed

    Ferrer, J F; Diglio, C A

    1976-03-01

    The ability of the bovine C-type leukemia virus to induce syncytia formation in monolayer cell cultures has been used to develop a specific and simple infectivity assay for the virus. Using bovine embryonic spleen cells or human diploid embryonic lung cells as indicator cells, the results of the assay can be evaluated in 4 to 6 or 6 to 8 days, respectively. Pretreatment of the indicator cells with DEAE-dextran greatly increases the sensitivity of the assay. The assay is quantitative and can be applied as a direct method for the identification of bovine C-type leukemia virus-infected animals; it also provides a simple, and sensitive procedure for the detection and titration of virus-neutralizing antibodies.

  8. Ruthenium red preserves glycoprotein peplomers of C-type retroviruses for transmission electron microscopy.

    PubMed

    Fassel, T A; Raisch, K P; Chetty, N; Grossberg, S E; Kushnaryov, V M

    1998-07-01

    Peplomers, the glycoprotein projections of the outer viral envelope, are distinctive for many viruses. Peplomers of retroviral C-type particles are fragile and are not preserved in standard preparations for transmission electron microscopy of thin sections, whereas the peplomers of B- and D- type retroviruses are usually preserved. Ruthenium red, extensively used in transmission electron microscopy to enhance the preservation of glycosylated proteins, was used in the preparation of three retrovirus-producing lymphoblastoid cell lines: murine SC-1 cells producing the C-type murine leukemia retrovirus LP-BM5 that causes immunodeficiency, human DG-75 cells producing a murine leukemia retrovirus, and human C5/MJ cells producing human T-cell lymphotropic virus type I (HTLV-I). Fixation of cells was carried out with ruthenium red present in the glutaraldehyde, osmium tetroxide, and the ethanol dehydration through the 70% ethanol step. The detailed structure of peplomers of these three different viruses was well preserved. PMID:9735881

  9. Supercapacitors based on c-type cytochromes using conductive nanostructured networks of living bacteria.

    PubMed

    Malvankar, Nikhil S; Mester, Tünde; Tuominen, Mark T; Lovley, Derek R

    2012-02-01

    Supercapacitors have attracted interest in energy storage because they have the potential to complement or replace batteries. Here, we report that c-type cytochromes, naturally immersed in a living, electrically conductive microbial biofilm, greatly enhance the device capacitance by over two orders of magnitude. We employ genetic engineering, protein unfolding and Nernstian modeling for in vivo demonstration of charge storage capacity of c-type cytochromes and perform electrochemical impedance spectroscopy, cyclic voltammetry and charge-discharge cycling to confirm the pseudocapacitive, redox nature of biofilm capacitance. The biofilms also show low self-discharge and good charge/discharge reversibility. The superior electrochemical performance of the biofilm is related to its high abundance of cytochromes, providing large electron storage capacity, its nanostructured network with metallic-like conductivity, and its porous architecture with hydrous nature, offering prospects for future low cost and environmentally sustainable energy storage devices.

  10. Computational Analysis of the Ligand Binding Site of the Extracellular ATP Receptor, DORN1

    PubMed Central

    Cao, Yangrong; Cho, Sung-Hwan; Xu, Dong; Stacey, Gary

    2016-01-01

    DORN1 (also known as P2K1) is a plant receptor for extracellular ATP, which belongs to a large gene family of legume-type (L-type) lectin receptor kinases. Extracellular ATP binds to DORN1 with strong affinity through its lectin domain, and the binding triggers a variety of intracellular activities in response to biotic and abiotic stresses. However, information on the tertiary structure of the ligand binding site of DORN1is lacking, which hampers efforts to fully elucidate the mechanism of receptor action. Available data of the crystal structures from more than 50 L-type lectins enable us to perform an in silico study of molecular interaction between DORN1 and ATP. In this study, we employed a computational approach to develop a tertiary structure model of the DORN1 lectin domain. A blind docking analysis demonstrated that ATP binds to a cavity made by four loops (defined as loops A B, C and D) of the DORN1 lectin domain with high affinity. In silico target docking of ATP to the DORN1 binding site predicted interaction with 12 residues, located on the four loops, via hydrogen bonds and hydrophobic interactions. The ATP binding pocket is structurally similar in location to the carbohydrate binding pocket of the canonical L-type lectins. However, four of the residues predicted to interact with ATP are not conserved between DORN1 and the other carbohydrate-binding lectins, suggesting that diversifying selection acting on these key residues may have led to the ATP binding activity of DORN1. The in silico model was validated by in vitro ATP binding assays using the purified extracellular lectin domain of wild-type DORN1, as well as mutated DORN1 lacking key ATP binding residues. PMID:27583834

  11. Computational Analysis of the Ligand Binding Site of the Extracellular ATP Receptor, DORN1.

    PubMed

    Nguyen, Cuong The; Tanaka, Kiwamu; Cao, Yangrong; Cho, Sung-Hwan; Xu, Dong; Stacey, Gary

    2016-01-01

    DORN1 (also known as P2K1) is a plant receptor for extracellular ATP, which belongs to a large gene family of legume-type (L-type) lectin receptor kinases. Extracellular ATP binds to DORN1 with strong affinity through its lectin domain, and the binding triggers a variety of intracellular activities in response to biotic and abiotic stresses. However, information on the tertiary structure of the ligand binding site of DORN1is lacking, which hampers efforts to fully elucidate the mechanism of receptor action. Available data of the crystal structures from more than 50 L-type lectins enable us to perform an in silico study of molecular interaction between DORN1 and ATP. In this study, we employed a computational approach to develop a tertiary structure model of the DORN1 lectin domain. A blind docking analysis demonstrated that ATP binds to a cavity made by four loops (defined as loops A B, C and D) of the DORN1 lectin domain with high affinity. In silico target docking of ATP to the DORN1 binding site predicted interaction with 12 residues, located on the four loops, via hydrogen bonds and hydrophobic interactions. The ATP binding pocket is structurally similar in location to the carbohydrate binding pocket of the canonical L-type lectins. However, four of the residues predicted to interact with ATP are not conserved between DORN1 and the other carbohydrate-binding lectins, suggesting that diversifying selection acting on these key residues may have led to the ATP binding activity of DORN1. The in silico model was validated by in vitro ATP binding assays using the purified extracellular lectin domain of wild-type DORN1, as well as mutated DORN1 lacking key ATP binding residues. PMID:27583834

  12. Computational Analysis of the Ligand Binding Site of the Extracellular ATP Receptor, DORN1.

    PubMed

    Nguyen, Cuong The; Tanaka, Kiwamu; Cao, Yangrong; Cho, Sung-Hwan; Xu, Dong; Stacey, Gary

    2016-01-01

    DORN1 (also known as P2K1) is a plant receptor for extracellular ATP, which belongs to a large gene family of legume-type (L-type) lectin receptor kinases. Extracellular ATP binds to DORN1 with strong affinity through its lectin domain, and the binding triggers a variety of intracellular activities in response to biotic and abiotic stresses. However, information on the tertiary structure of the ligand binding site of DORN1is lacking, which hampers efforts to fully elucidate the mechanism of receptor action. Available data of the crystal structures from more than 50 L-type lectins enable us to perform an in silico study of molecular interaction between DORN1 and ATP. In this study, we employed a computational approach to develop a tertiary structure model of the DORN1 lectin domain. A blind docking analysis demonstrated that ATP binds to a cavity made by four loops (defined as loops A B, C and D) of the DORN1 lectin domain with high affinity. In silico target docking of ATP to the DORN1 binding site predicted interaction with 12 residues, located on the four loops, via hydrogen bonds and hydrophobic interactions. The ATP binding pocket is structurally similar in location to the carbohydrate binding pocket of the canonical L-type lectins. However, four of the residues predicted to interact with ATP are not conserved between DORN1 and the other carbohydrate-binding lectins, suggesting that diversifying selection acting on these key residues may have led to the ATP binding activity of DORN1. The in silico model was validated by in vitro ATP binding assays using the purified extracellular lectin domain of wild-type DORN1, as well as mutated DORN1 lacking key ATP binding residues.

  13. Order within a mosaic distribution of mitochondrial c-type cytochrome biogenesis systems?

    PubMed

    Allen, James W A; Jackson, Andrew P; Rigden, Daniel J; Willis, Antony C; Ferguson, Stuart J; Ginger, Michael L

    2008-05-01

    Mitochondrial cytochromes c and c(1) are present in all eukaryotes that use oxygen as the terminal electron acceptor in the respiratory chain. Maturation of c-type cytochromes requires covalent attachment of the heme cofactor to the protein, and there are at least five distinct biogenesis systems that catalyze this post-translational modification in different organisms and organelles. In this study, we use biochemical data, comparative genomic and structural bioinformatics investigations to provide a holistic view of mitochondrial c-type cytochrome biogenesis and its evolution. There are three pathways for mitochondrial c-type cytochrome maturation, only one of which is present in prokaryotes. We analyze the evolutionary distribution of these biogenesis systems, which include the Ccm system (System I) and the enzyme heme lyase (System III). We conclude that heme lyase evolved once and, in many lineages, replaced the multicomponent Ccm system (present in the proto-mitochondrial endosymbiont), probably as a consequence of lateral gene transfer. We find no evidence of a System III precursor in prokaryotes, and argue that System III is incompatible with multi-heme cytochromes common to bacteria, but absent from eukaryotes. The evolution of the eukaryotic-specific protein heme lyase is strikingly unusual, given that this protein provides a function (thioether bond formation) that is also ubiquitous in prokaryotes. The absence of any known c-type cytochrome biogenesis system from the sequenced genomes of various trypanosome species indicates the presence of a third distinct mitochondrial pathway. Interestingly, this system attaches heme to mitochondrial cytochromes c that contain only one cysteine residue, rather than the usual two, within the heme-binding motif. The isolation of single-cysteine-containing mitochondrial cytochromes c from free-living kinetoplastids, Euglena and the marine flagellate Diplonema papillatum suggests that this unique form of heme attachment