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Sample records for lectin activates c3

  1. Mannan-binding lectin activates C3 and the

    DEFF Research Database (Denmark)

    Selander, B.; Martensson, U.; Weintraub, A.

    2006-01-01

    Lectin pathway activation of C3 is known to involve target recognition by mannan-binding lectin (MBL) or ficolins and generation of classical pathway C3 convertase via cleavage of C4 and C2 by MBL-associated serine protease 2 (MASP-2). We investigated C3 activation in C2-deficient human sera...... and in sera with other defined defects of complement to assess other mechanisms through which MBL might recruit complement. The capacity of serum to support C3 deposition was examined by ELISA using microtiter plates coated with O antigen-specific oligosaccharides derived from Salmonella typhimurium, S...

  2. Lectins with Anti-HIV Activity: A Review

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    Ouafae Akkouh

    2015-01-01

    Full Text Available 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.

  3. Characterization and antimicrobial activity of lectins from Penicillium sp.

    Science.gov (United States)

    Singh, R S; Jain, P; Kaur, H P

    2013-11-01

    Ten Penicillium sp. were screened for lectin activity for occurrence of lectins. Mycelial extracts from submerged cultures of P. corylophilum, P. expansum and P. purpurogenum showed agglutination against human (A, B, AB and O), goat, sheep, pig and rabbit erythrocytes. Neuraminidase treatment to human blood- type O erythrocytes substantially increased their agglutinability by all the lectins as compared to untreated erythrocytes. Modification of erythrocyte surfaces by protease increased the lectin titre only of P. corylophilum with no effect on other two lectins. P. corylophilum and P. expansum displayed relatively lower titres in mycelial extracts prepared from agar plate cultures as compared to broth cultures. A panel of sugars was tested for inhibition of lectin activity. All the lectins were found to be specific for asialofetuin, bovine submaxillary mucin, porcine stomach mucin, chondroitin-6-sulphate, D-sucrose and D-glucose. P. corylophilum lectin was expressed (Titre 8) by 5 day old cultures, reaching its maximum level (Titre 32) upon 8 days of cultivation, thereafter declin in lectin activity was observed. P. purpurogenum lectin was expressed by 7-10 days old cultures, while in P. expansum maximum lectin activity was elaborated by 5-8 days old cultures. Lectin extracts from all the three species were found to possess antimicrobial activities. Lectin extracts from the three Penicillium species displayed antifungal activity and antibacterial activity against Gram-negative and Gram-positive bacterial strains.

  4. New perspectives on mannan-binding lectin-mediated complement activation

    DEFF Research Database (Denmark)

    Degn, Søren Egedal; Thiel, Steffen; Jensenius, Jens Christian

    2007-01-01

    The complement system is an important part of the innate immune system, mediating several major effector functions and modulating adaptive immune responses. Three complement activation pathways exist: the classical pathway (CP), the alternative pathway (AP), and the lectin pathway (LP). The LP......, allowing C3 activation in the absence of components otherwise believed critical. The classical bypass pathways are dependent on C1 and components of the AP. A recent study has shown the existence also of a lectin bypass pathway dependent on mannan-binding lectin (MBL) and AP components. The emerging...

  5. A Revised Mechanism for the Activation of Complement C3 to C3b

    Science.gov (United States)

    Rodriguez, Elizabeth; Nan, Ruodan; Li, Keying; Gor, Jayesh; Perkins, Stephen J.

    2015-01-01

    The solution structure of complement C3b is crucial for the understanding of complement activation and regulation. C3b is generated by the removal of C3a from C3. Hydrolysis of the C3 thioester produces C3u, an analog of C3b. C3b cleavage results in C3c and C3d (thioester-containing domain; TED). To resolve functional questions in relation to C3b and C3u, analytical ultracentrifugation and x-ray and neutron scattering studies were used with C3, C3b, C3u, C3c, and C3d, using the wild-type allotype with Arg102. In 50 mm NaCl buffer, atomistic scattering modeling showed that both C3b and C3u adopted a compact structure, similar to the C3b crystal structure in which its TED and macroglobulin 1 (MG1) domains were connected through the Arg102–Glu1032 salt bridge. In physiological 137 mm NaCl, scattering modeling showed that C3b and C3u were both extended in structure, with the TED and MG1 domains now separated by up to 6 nm. The importance of the Arg102–Glu1032 salt bridge was determined using surface plasmon resonance to monitor the binding of wild-type C3d(E1032) and mutant C3d(A1032) to immobilized C3c. The mutant did not bind, whereas the wild-type form did. The high conformational variability of TED in C3b in physiological buffer showed that C3b is more reactive than previously thought. Because the Arg102-Glu1032 salt bridge is essential for the C3b-Factor H complex during the regulatory control of C3b, the known clinical associations of the major C3S (Arg102) and disease-linked C3F (Gly102) allotypes of C3b were experimentally explained for the first time. PMID:25488663

  6. IDENTIFICATION OF LECTINS OF ZEA MAYS RAW MATERIAL AND THE STUDY OF LECTIN ACTIVITY

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    Karpiuk UV

    2013-03-01

    Full Text Available The aime of the study was to identify lectins in the Zea mays raw material: roots, stems, heads, leaves and corn silk and study their activity. Lectins activity has been studied using the biological method of ratuserytroagglutination. This method is based on formation of aggregates of lectins and rats erythrocytes. The activity unit was the floor amount of lectins that agglutinate erythrocytes. The protein nature of extracts that agglutinate has been determined using Bradford method. The lectins activity of Zea mays roots was 6,21±0,11 unit/mg of protein; of heads – 2,61±0,17 unit/mg of protein; of leaves – 0,62 ±0,05 unit/mg of protein; of corn silk – 1,06±0,08 unit/mg of protein; of stems – 0,97±0,09 unit/mg of protein. The greatest lectins activity was in leaves, stems and corn silk.

  7. Activation of the lectin complement pathway on human renal ...

    African Journals Online (AJOL)

    This study aimed to investigate the roles of high glucose and mannose-binding lectin (MBL) on the activation of the lectin complement pathway (LCP) on human renal glomerular endothelial cells (HRGECs) in vitro. Flow cytometry analysis, immunofluorescence staining and Western blot were used to detect the cell surface ...

  8. Lectin activity in mycelial extracts of Fusarium species.

    Science.gov (United States)

    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. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  9. Characterization of chickpea (Cicer arietinum L.) lectin for biological activity.

    Science.gov (United States)

    Gautam, Ajay Kumar; Gupta, Neha; Narvekar, Dakshita T; Bhadkariya, Rajni; Bhagyawant, Sameer S

    2018-05-01

    Lectins are proteins that are subject of intense investigations. Information on lectin from chickpea ( Cicer arietinum L.) with respect to its biological activities are very limited. In this study, we purified lectin from the seeds of chickpea employing DEAE-cellulose and SP-Sephadex ion exchange chromatography and identified its molecular subunit mass as 35 kDa. The free radical scavenging activity of lectin measured by the DPPH assay has IC 50 of 0.88 µg/mL. Lectin exerted antifungal activity against Candida krusei , Fusarium oxysporium oxysporium , Saccharomyces cerevisiae and Candida albicans , while antibacterial activity against E. coli , B. subtilis , S. marcescens and P. aeruginosa. The minimum inhibitory concentrations were 200, 240, 160 and 140 µg for C. krusei, F. oxysporium , S. cerevisiae and C. albicans respectively. Lectin was further examined for its antiproliferative potential against cancerous cell line. The cell viability assay indicated a high inhibition activity on Ishikawa, HepG2, MCF-7 and MDA-MB-231 with IC 50 value of 46.67, 44.20, 53.58 and 37.46 µg/mL respectively. These results can provide a background for future research into the benefits of chickpea lectin to pharmacological perspective.

  10. Cholesterol Crystals Activate the Lectin Complement Pathway via Ficolin-2 and Mannose-Binding Lectin

    DEFF Research Database (Denmark)

    Pilely, Katrine; Rosbjerg, Anne; Genster, Ninette

    2016-01-01

    Cholesterol crystals (CC) play an essential role in the formation of atherosclerotic plaques. CC activate the classical and the alternative complement pathways, but the role of the lectin pathway is unknown. We hypothesized that the pattern recognition molecules (PRMs) from the lectin pathway bind...... CC and function as an upstream innate inflammatory signal in the pathophysiology of atherosclerosis. We investigated the binding of the PRMs mannose-binding lectin (MBL), ficolin-1, ficolin-2, and ficolin-3, the associated serine proteases, and complement activation products to CC in vitro using...... recognize CC and provides evidence for an important role for this pathway in the inflammatory response induced by CC in the pathophysiology of atherosclerosis....

  11. Insights into Animal and Plant Lectins with Antimicrobial Activities

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    Renata de Oliveira Dias

    2015-01-01

    Full Text Available 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.

  12. Antifungal activity of lectins against yeast of vaginal secretion

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    Bruno Severo Gomes

    2012-06-01

    Full Text Available 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.

  13. Self-association and domain rearrangements between complement C3 and C3u provide insight into the activation mechanism of C3.

    Science.gov (United States)

    Li, Keying; Gor, Jayesh; Perkins, Stephen J

    2010-10-01

    Component C3 is the central protein of the complement system. During complement activation, the thioester group in C3 is slowly hydrolysed to form C3u, then the presence of C3u enables the rapid conversion of C3 into functionally active C3b. C3u shows functional similarities to C3b. To clarify this mechanism, the self-association properties and solution structures of C3 and C3u were determined using analytical ultracentrifugation and X-ray scattering. Sedimentation coefficients identified two different dimerization events in both proteins. A fast dimerization was observed in 50 mM NaCl but not in 137 mM NaCl. Low amounts of a slow dimerization was observed for C3u and C3 in both buffers. The X-ray radius of gyration RG values were unchanged for both C3 and C3u in 137 mM NaCl, but depend on concentration in 50 mM NaCl. The C3 crystal structure gave good X-ray fits for C3 in 137 mM NaCl. By randomization of the TED (thioester-containing domain)/CUB (for complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domains in the C3b crystal structure, X-ray fits showed that the TED/CUB domains in C3u are extended and differ from the more compact arrangement of C3b. This TED/CUB conformation is intermediate between those of C3 and C3b. The greater exposure of the TED domain in C3u (which possesses the hydrolysed reactive thioester) accounts for the greater self-association of C3u in low-salt conditions. This conformational variability of the TED/CUB domains would facilitate their interactions with a broad range of antigenic surfaces. The second dimerization of C3 and C3u may correspond to a dimer observed in one of the crystal structures of C3b.

  14. Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Skjoedt, Mikkel-Ole; Garred, Peter

    2013-01-01

    Collectins and ficolins are important in the clearance of endogenous and exogenous danger materials. A new human collectin-11 was recently identified in low concentration in serum in complex with mannose-binding lectin (MBL)/ficolin-associated serine proteases. Collectin-11 binds to carbohydrate...... complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway...

  15. Pseudomonas aeruginosa alkaline protease blocks complement activation via the classical and lectin pathways.

    Science.gov (United States)

    Laarman, Alexander J; Bardoel, Bart W; Ruyken, Maartje; Fernie, Job; Milder, Fin J; van Strijp, Jos A G; Rooijakkers, Suzan H M

    2012-01-01

    The complement system rapidly detects and kills Gram-negative bacteria and supports bacterial killing by phagocytes. However, bacterial pathogens exploit several strategies to evade detection by the complement system. The alkaline protease (AprA) of Pseudomonas aeruginosa has been associated with bacterial virulence and is known to interfere with complement-mediated lysis of erythrocytes, but its exact role in bacterial complement escape is unknown. In this study, we analyzed how AprA interferes with complement activation and whether it could block complement-dependent neutrophil functions. We found that AprA potently blocked phagocytosis and killing of Pseudomonas by human neutrophils. Furthermore, AprA inhibited opsonization of bacteria with C3b and the formation of the chemotactic agent C5a. AprA specifically blocked C3b deposition via the classical and lectin pathways, whereas the alternative pathway was not affected. Serum degradation assays revealed that AprA degrades both human C1s and C2. However, repletion assays demonstrated that the mechanism of action for complement inhibition is cleavage of C2. In summary, we showed that P. aeruginosa AprA interferes with classical and lectin pathway-mediated complement activation via cleavage of C2.

  16. Activities of lectins and their immobilized derivatives in detergent solutions. Implications on the use of lectin affinity chromatography for the purification of membrane glycoproteins.

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    Lotan, R; Beattie, G; Hubbell, W; Nicolson, G L

    1977-05-03

    The effects of several commonly used detergents on the saccharide-binding activities of lectins were investigated using lectin-mediated agglutination of formalin-fixed erythrocytes and affinity chromatography of glycoproteins on columns of lectins immobilized on polyacrylic hydrazide-Sepharose. In the hemagglutination assays, Ricinus communis I (RCA1) and II (RCAII), concanavalin A (Con A), and the agglutinins from peanut (PNA), soybean (SBA), wheat germ (WGA), and Limulus polyphemus (LPA) were tested with several concentrations of switterionic, cationic, anionic, and nonionic detergents. It was found that increasing detergent concentrations eventually affected hemagglutination titers in both test and control samples, and the highest detergent concentrations not affecting lectin hemagglutinating activities were determined. The effects of detergents on specific binding of [3H]fetuin and asialo[3H]fetuin to and elution from columns of immobilized lectins were less severe when compared with lectins in solution, suggesting that the lectins are stabilized by covalent attachment to agarose beads. Nonionic detergents did not affect the binding efficiency of the immobilized lectins tested at concentrations used for membrane solubilization while cationic and zwitterionic detergents caused significant inhibition of Con A- and SBA-Sepharose activities. In sodium deoxycholate (greater than 1%) only RCAI-Sepharose retained its activity, whereas the activities of the other lectins were reduced dramatically. Low concentrations of sodium dodecyl sulfate (0.05%) inhibited only the activity of immobilized SBA, but at higher concentration (0.1%) and prolonged periods of incubation (16 h, 23 degrees C) most of the lectins were inactivated. These data are compared with previous reports on the use of detergents in lectin affinity chromatography, and the conditions for the optimal use of detergents are detailed.

  17. Mitogenic activity of new lectins from seeds of wild Artocarpus species from Vietnam.

    Science.gov (United States)

    Blasco, E; Ngoc, L D; Aucouturier, P; Preud'Homme, J L; Barra, A

    1996-05-01

    Proliferative response of human peripheral blood mononuclear cells (PBMC) stimulated by new lectins purified from seeds of differents Artocarpus species from Vietnam (A. asperulus, A. heterophyllus, A. masticata, A. melinoxylus, A. parva and A. petelotii) was studied and compared to those of the lectin jacalin purified from jackfruit (A. heterophyllus) seeds collected in the island La Réunion. All lectins stimulated human PBMC to proliferate, with a variable efficiency of the mitogenic activity. Phenotypic analysis of cells recovered after 7 day-cultures showed that these lectins mostly stimulated CD4+ T lymphocytes. These results suggest that these lectins from different Artocarpus species are similar in terms of their mitogenic activity although their structural features are not identical.

  18. Purification and characterization of a mucin specific mycelial lectin from Aspergillus gorakhpurensis: application for mitogenic and antimicrobial activity.

    Science.gov (United States)

    Singh, Ram Sarup; Kaur, Hemant Preet; Singh, Jatinder

    2014-01-01

    Lectins are carbohydrate binding proteins or glycoproteins that bind reversibly to specific carbohydrates present on the apposing cells, which are responsible for their ability to agglutinate red blood cells, lymphocytes, fibroblasts, etc. Interest in lectins has been intensified due to their carbohydrate specificity as they can be valuable reagents for the investigation of cell surface sugars, purification and characterization of glycoproteins. The present study reports the purification, characterization and evaluation of mitogenic and antimicrobial potential of a mycelial lectin from Aspergillus gorakhpurensis. Affinity chromatography on mucin-sepharose column was carried out for purification of Aspergillus gorakhpurensis lectin. The lectin was characterized for physico-chemical parameters. Mitogenic potential of the lectin was evaluated against splenocytes of Swiss albino mice by MTT assay. Antimicrobial activity of the purified lectin has also been evaluated by disc diffusion assay. Single-step affinity purification resulted in 18.6-fold purification of the mycelial lectin. The molecular mass of the lectin was found to be 70 kDa and it was composed of two subunits of 34.8 kDa as determined by gel filtration chromatography, SDS-PAGE and MALDI-TOF analysis. pH optima of the lectin was found to be 6.5-9.5, while optimum temperature for lectin activity was 20-30 °C. Lectin was stable within a pH range of 7.0-10.5 and showed fair thermostability. EDTA did not affect lectin activity whereas it was found susceptible to the denaturants tested. MTT assay revealed strong mitogenic potential of A. gorakhpurensis lectin at a concentration upto 150 µg/mL. Antimicrobial activity assay showed its potent antibacterial activity against Bacillus cereus, Staphylococcous aureus and Escherichia coli and marginal antifungal activity against Saccharomyces cerevisiae. This is the first report on the mitogenic and antimicrobial potential of Aspergillus gorakhpurensis lectin. The

  19. Increased Autoreactivity of the Complement-Activating Molecule Mannan-Binding Lectin in a Type 1 Diabetes Model

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    Jakob Appel Østergaard

    2016-01-01

    Full Text Available Background. Diabetic kidney disease is the leading cause of end-stage renal failure despite intensive treatment of modifiable risk factors. Identification of new drug targets is therefore of paramount importance. The complement system is emerging as a potential new target. The lectin pathway of the complement system, initiated by the carbohydrate-recognition molecule mannan-binding lectin (MBL, is linked to poor kidney prognosis in diabetes. We hypothesized that MBL activates complement upon binding within the diabetic glomerulus. Methods. We investigated this by comparing complement deposition and activation in kidneys from streptozotocin-induced diabetic mice and healthy control mice. Results. After 20 weeks of diabetes, glomerular deposition of MBL was significantly increased. Diabetic animals had 2.0-fold higher (95% CI 1.6–2.5 immunofluorescence intensity from anti-MBL antibodies compared with controls (P<0.001. Diabetes and control groups did not differ in glomerular immunofluorescence intensity obtained by antibodies against complement factors C4, C3, and C9. However, the circulating complement activation product C3a was increased in diabetes as compared to control mice (P=0.04. Conclusion. 20 weeks of diabetes increased MBL autoreactivity in the kidney and circulating C3a concentration. Together with previous findings, these results indicate direct effects of MBL within the kidney in diabetes.

  20. A revised mechanism for the activation of complement C3 to C3b: a molecular explanation of a disease-associated polymorphism.

    Science.gov (United States)

    Rodriguez, Elizabeth; Nan, Ruodan; Li, Keying; Gor, Jayesh; Perkins, Stephen J

    2015-01-23

    The solution structure of complement C3b is crucial for the understanding of complement activation and regulation. C3b is generated by the removal of C3a from C3. Hydrolysis of the C3 thioester produces C3u, an analog of C3b. C3b cleavage results in C3c and C3d (thioester-containing domain; TED). To resolve functional questions in relation to C3b and C3u, analytical ultracentrifugation and x-ray and neutron scattering studies were used with C3, C3b, C3u, C3c, and C3d, using the wild-type allotype with Arg(102). In 50 mm NaCl buffer, atomistic scattering modeling showed that both C3b and C3u adopted a compact structure, similar to the C3b crystal structure in which its TED and macroglobulin 1 (MG1) domains were connected through the Arg(102)-Glu(1032) salt bridge. In physiological 137 mm NaCl, scattering modeling showed that C3b and C3u were both extended in structure, with the TED and MG1 domains now separated by up to 6 nm. The importance of the Arg(102)-Glu(1032) salt bridge was determined using surface plasmon resonance to monitor the binding of wild-type C3d(E1032) and mutant C3d(A1032) to immobilized C3c. The mutant did not bind, whereas the wild-type form did. The high conformational variability of TED in C3b in physiological buffer showed that C3b is more reactive than previously thought. Because the Arg(102)-Glu(1032) salt bridge is essential for the C3b-Factor H complex during the regulatory control of C3b, the known clinical associations of the major C3S (Arg(102)) and disease-linked C3F (Gly(102)) allotypes of C3b were experimentally explained for the first time. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. The identification of plant lectins with mucosal adjuvant activity

    Science.gov (United States)

    Lavelle, E C; Grant, G; Pusztai, A; Pfüller, U; O'hagan, D T

    2001-01-01

    To date, the most potent mucosal vaccine adjuvants to be identified have been bacterial toxins. The present data demonstrate that the type 2 ribosome-inactivating protein (type 2 RIP), mistletoe lectin I (ML-I) is a strong mucosal adjuvant of plant origin. A number of plant lectins were investigated as intranasal (i.n.) coadjuvants for a bystander protein, ovalbumin (OVA). As a positive control, a potent mucosal adjuvant, cholera toxin (CT), was used. Co-administration of ML-I or CT with OVA stimulated high titres of OVA-specific serum immunoglobulin G (IgG) in addition to OVA-specific IgA in mucosal secretions. CT and ML-I were also strongly immunogenic, inducing high titres of specific serum IgG and specific IgA at mucosal sites. None of the other plant lectins investigated significantly boosted the response to co-administered OVA. Immunization with phytohaemagglutinin (PHA) plus OVA elicited a lectin-specific response but did not stimulate an enhanced response to OVA compared with the antigen alone. Intranasal delivery of tomato lectin (LEA) elicited a strong lectin-specific systemic and mucosal antibody response but only weakly potentiated the response to co-delivered OVA. In contrast, administration of wheatgerm agglutinin (WGA) or Ulex europaeus lectin 1 (UEA-I) with OVA stimulated a serum IgG response to OVA while the lectin-specific responses (particularly for WGA) were relatively low. Thus, there was not a direct correlation between immunogenicity and adjuvanticity although the strongest adjuvants (CT, ML-I) were also highly immunogenic. PMID:11168640

  2. Lysis of fresh human solid tumors by autologous lymphocytes activated in vitro with lectins

    International Nuclear Information System (INIS)

    Mazumder, A.; Grimm, E.A.; Zhang, H.Z.; Rosenberg, S.A.

    1982-01-01

    Human peripheral blood lymphocytes (PBL), obtained from patients with a variety of cancers, were incubated in vitro with phytohemagglutinin, concanavalin A, and crude or lectin-free T-cell growth factors. The lectin-activated PBL of nine patients were capable of lysing fresh autologous tumor during a 4-hr 51Cr release assay. Multiple metastases from the same patient were equivalently lysed by these activated autologous PBL. No lysis of fresh PBL or lectin-induced lymphoblast cell targets was seen, although tumor, PBL, and lymphoblast cells were shown to be equally lysable using allosensitized cells. The activated cells could be expanded without loss of cytotoxicity in crude or lectin-free T-cell growth factors. The generation of cells lytic to fresh autologous tumor was dependent on the presence of adherent cells, although the lytic cell itself was not adherent. Proliferation was not involved in the induction of lytic cells since equal lysis was induced in irradiated and nonirradiated lymphocytes. Lectin was not required in the lytic assay, and the addition of alpha-methyl-D-mannoside to concanavalin A-activated lymphoid cells did not increase the lysis of fresh tumor cells. Activation by lectin for 3 days appears to be an efficient and convenient method for generating human cells lytic to fresh autologous tumor. These lytic cells may be of value for studies of the cell-mediated lysis of human tumor and possibly for tumor immunotherapy as well

  3. [Effect of Azospirillum lectins on the Activity of Proteolytic Enzymes and Their Inhibitors in Wheat Seedling Roots].

    Science.gov (United States)

    Alen'kina, S A; Nikitina, V E

    2015-01-01

    The lectins of associative nitrogen-fixing strains Azospirillum brasilense Sp7 and Sp245 were shown to exerte a multidirectional effect on the activity of acidic (pH 3.5), neutral (6.8), and alkaline (pH 7.8) proteinases. The lectin of the epiphytic A. brasilense Sp7 decreased proteolytic activity at all pH values, whereas the lectin of the endophytic A. brasilense Sp245 activated neutral and alkaline proteinases, while not affecting the alkaline ones. Experiments with protease inhibitors made it possible to conclude that the lectins of the studied A. brasilense strains alter the ratio between the activities of different protease types in germinating seeds. The activity of trypsin inhibitors in wheat seedling roots was found to increase in the presence of the lectins. Our results indicate a broader spectrum of effects of azospirilla lectins on the host plant organism.

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

    Science.gov (United States)

    Osthoff, Michael; Brown, Karl D; Kong, David C M; Daniell, Mark; Eisen, Damon P

    2014-01-01

    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. 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. 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. 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.

  5. Characterization of the third component of complement (C3) after activation by cigarette smoke

    International Nuclear Information System (INIS)

    Kew, R.R.; Ghebrehiwet, B.; Janoff, A.

    1987-01-01

    Activation of lung complement by tobacco smoke may be an important pathogenetic factor in the development of pulmonary emphysema in smokers. We previously showed that cigarette smoke can modify C3 and activate the alternative pathway of complement in vitro. However, the mechanism of C3 activation was not fully delineated in these earlier studies. In the present report, we show that smoke-treated C3 induces cleavage of the alternative pathway protein, Factor B, when added to serum containing Mg-EGTA. This effect of cigarette smoke is specific for C3 since smoke-treated C4, when added to Mg-EGTA-treated serum, fails to activate the alternative pathway and fails to induce Factor B cleavage. Smoke-modified C3 no longer binds significant amounts of [ 14 C]methylamine (as does native C3), and relatively little [ 14 C]methylamine is incorporated into its alpha-chain. Thus, prior internal thiolester bond cleavage appears to have occurred in C3 activated by cigarette smoke. Cigarette smoke components also induce formation of noncovalently associated, soluble C3 multimers, with a Mr ranging from 1 to 10 million. However, prior cleavage of the thiolester bond in C3 with methylamine prevents the subsequent formation of these smoke-induced aggregates. These data indicate that cigarette smoke activates the alternative pathway of complement by specifically modifying C3 and that these modifications include cleavage of the thiolester bond in C3 and formation of noncovalently linked C3 multimers

  6. The C-type lectin of the aggrecan G3 domain activates complement.

    Directory of Open Access Journals (Sweden)

    Camilla Melin Fürst

    Full Text Available Excessive complement activation contributes to joint diseases such as rheumatoid arthritis and osteoarthritis during which cartilage proteins are fragmented and released into the synovial fluid. Some of these proteins and fragments activate complement, which may sustain inflammation. The G3 domain of large cartilage proteoglycan aggrecan interacts with other extracellular matrix proteins, fibulins and tenascins, via its C-type lectin domain (CLD and has important functions in matrix organization. Fragments containing G3 domain are released during normal aggrecan turnover, but increasingly so in disease. We now show that the aggrecan CLD part of the G3 domain activates the classical and to a lesser extent the alternative pathway of complement, via binding of C1q and C3, respectively. The complement control protein (CCP domain adjacent to the CLD showed no effect on complement initiation. The binding of C1q to G3 depended on ionic interactions and was decreased in D2267N mutant G3. However, the observed complement activation was attenuated due to binding of complement inhibitor factor H to CLD and CCP domains. This was most apparent at the level of deposition of terminal complement components. Taken together our observations indicate aggrecan CLD as one factor involved in the sustained inflammation of the joint.

  7. Antiproliferative activity of cytotoxic tuber lectins from Solanum ...

    African Journals Online (AJOL)

    SAM

    2014-04-09

    Apr 9, 2014 ... E-mail: hasanimtiaj@yahoo.co.uk, rashelkabir@ru.ac.bd. .... blue and then counted by a hemocytometer under an inverted microscope (XDS-1R .... and lectin-treated mice counted by a light microscope on day. 6 of tumor ...

  8. [Inhibition by cysteine of the carbohydrate-binding activity of lectins from Ricinus communis, Canavalia ensiformis and Euonymus europaeus].

    Science.gov (United States)

    Dvorkin, V M

    1985-10-01

    Precipitation induced by different lectins has been studied in the presence of some aminoacids. It was shown that precipitates formed by lectins from Ricinus communis (RCA1), Canavalia ensiformis (Con A), Euonymus europaeus (Eel) in the presence of appropriate carbohydrate-containing molecules disappeared after cysteine addition, like after addition of specific carbohydrate precipitation inhibitors. It is assumed that cysteine residues of RCA1, Con A and Eel lectins are essential for their carbohydrate binding activity.

  9. Purification of a lectin from Eugenia uniflora L. seeds and its potential antibacterial activity.

    Science.gov (United States)

    Oliveira, M D L; Andrade, C A S; Santos-Magalhães, N S; Coelho, L C B B; Teixeira, J A; Carneiro-da-Cunha, M G; Correia, M T S

    2008-03-01

    The aim of this work was to analyse the antimicrobial properties of a purified lectin from Eugenia uniflora L. seeds. The E. uniflora lectin (EuniSL) was isolated from the seed extract and purified by ion-exchange chromatography in DEAE-Sephadex with a purification factor of 11.68. The purified lectin showed a single band on denaturing electrophoresis, with a molecular mass of 67 kDa. EuniSL agglutinated rabbit and human erythrocytes with a higher specificity for rabbit erythrocytes. The haemagglutination was not inhibited by the tested carbohydrates but glycoproteins exerted a strong inhibitory action. The lectin proved to be thermo resistant with the highest stability at pH 6.5 and divalent ions did not affect its activity. EuniSL demonstrated a remarkable nonselective antibacterial activity. EuniSL strongly inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella sp. with a minimum inhibitory concentration (MIC) of 1.5 microg ml(-1), and moderately inhibited the growth of Bacillus subtilis, Streptococcus sp. and Escherichia coli with a MIC of 16.5 microg ml(-1). EuniSL was found to be effective against bacteria. The strong antibacterial activity of the studied lectin indicates a high potential for clinical microbiology and therapeutic applications.

  10. Purification and characterization of a mucin specific mycelial lectin from Aspergillus gorakhpurensis: application for mitogenic and antimicrobial activity.

    Directory of Open Access Journals (Sweden)

    Ram Sarup Singh

    Full Text Available Lectins are carbohydrate binding proteins or glycoproteins that bind reversibly to specific carbohydrates present on the apposing cells, which are responsible for their ability to agglutinate red blood cells, lymphocytes, fibroblasts, etc. Interest in lectins has been intensified due to their carbohydrate specificity as they can be valuable reagents for the investigation of cell surface sugars, purification and characterization of glycoproteins. The present study reports the purification, characterization and evaluation of mitogenic and antimicrobial potential of a mycelial lectin from Aspergillus gorakhpurensis.Affinity chromatography on mucin-sepharose column was carried out for purification of Aspergillus gorakhpurensis lectin. The lectin was characterized for physico-chemical parameters. Mitogenic potential of the lectin was evaluated against splenocytes of Swiss albino mice by MTT assay. Antimicrobial activity of the purified lectin has also been evaluated by disc diffusion assay.Single-step affinity purification resulted in 18.6-fold purification of the mycelial lectin. The molecular mass of the lectin was found to be 70 kDa and it was composed of two subunits of 34.8 kDa as determined by gel filtration chromatography, SDS-PAGE and MALDI-TOF analysis. pH optima of the lectin was found to be 6.5-9.5, while optimum temperature for lectin activity was 20-30 °C. Lectin was stable within a pH range of 7.0-10.5 and showed fair thermostability. EDTA did not affect lectin activity whereas it was found susceptible to the denaturants tested. MTT assay revealed strong mitogenic potential of A. gorakhpurensis lectin at a concentration upto 150 µg/mL. Antimicrobial activity assay showed its potent antibacterial activity against Bacillus cereus, Staphylococcous aureus and Escherichia coli and marginal antifungal activity against Saccharomyces cerevisiae.This is the first report on the mitogenic and antimicrobial potential of Aspergillus gorakhpurensis

  11. Direct demonstration of the lectin activity of gp90MEL, a lymphocyte homing receptor

    Science.gov (United States)

    1990-01-01

    Considerable evidence implicates gp90MEL as a lymphocyte homing receptor mediating lymphocyte attachment to high endothelial venules of lymph nodes in mouse. The protein appears to function as a calcium- dependent, lectin-like receptor as inferred primarily by the ability of specific carbohydrates to block its function and by the presence of a calcium-type lectin domain in its primary sequence. An ELISA assay is described which provides the first demonstration that the isolated protein has lectin activity and allows a further definition of its carbohydrate specificity. In addition to the monosaccharides mannose-6- phosphate and fructose-1-phosphate, ligand activity is shown for the sulfated glycolipid, sulfatide, and for two sulfated fucose-containing polysaccharides (fucoidin and egg jelly coat) from nonmammalian sources. PMID:2202735

  12. Structural insight into the recognition of complement C3 activation products by integrin receptors

    DEFF Research Database (Denmark)

    Bajic, Goran

    2015-01-01

    fragment C3a called anaphylatoxin. Complement leads to opsonization as the proteolytic fragment C3b becomes covalently linked to the activator surface through a reactive thioester. Self-surfaces are protected by complement regulators, whereas complement activation vividly amplifies on pathogens...... and their clearance by dendritic cells is mediated by αMβ2. The central molecule in my project, αMβ2 integrin, recognizes many diverse ligands including iC3b, but the molecular basis for such recognition was lacking. During my PhD I have obtained a major breakthrough in the dissection of iC3b interaction with αMβ2. I...

  13. Lectin Pathway of Complement Activation Is Associated with Vulnerability of Atherosclerotic Plaques

    DEFF Research Database (Denmark)

    Fumagalli, Stefano; Perego, Carlo; Zangari, Rosalia

    2017-01-01

    Inflammatory mechanisms may be involved in atherosclerotic plaque rupture. By using a novel histology-based method to quantify plaque instability here, we assess whether lectin pathway (LP) of complement activation, a major inflammation arm, could represent an index of plaque instability. Plaques...

  14. Structural insights into the anti-HIV activity of the Oscillatoria agardhii agglutinin homolog lectin family.

    Science.gov (United States)

    Koharudin, Leonardus M I; Kollipara, Sireesha; Aiken, Christopher; Gronenborn, Angela M

    2012-09-28

    Oscillatoria agardhii agglutinin homolog (OAAH) proteins belong to a recently discovered lectin family. All members contain a sequence repeat of ~66 amino acids, with the number of repeats varying among different family members. Apart from data for the founding member OAA, neither three-dimensional structures, information about carbohydrate binding specificities, nor antiviral activity data have been available up to now for any other members of the OAAH family. To elucidate the structural basis for the antiviral mechanism of OAAHs, we determined the crystal structures of Pseudomonas fluorescens and Myxococcus xanthus lectins. Both proteins exhibit the same fold, resembling the founding family member, OAA, with minor differences in loop conformations. Carbohydrate binding studies by NMR and x-ray structures of glycan-lectin complexes reveal that the number of sugar binding sites corresponds to the number of sequence repeats in each protein. As for OAA, tight and specific binding to α3,α6-mannopentaose was observed. All the OAAH proteins described here exhibit potent anti-HIV activity at comparable levels. Altogether, our results provide structural details of the protein-carbohydrate interaction for this novel lectin family and insights into the molecular basis of their HIV inactivation properties.

  15. Galactose-binding lectin from mulberry (Morus alba L. seeds with growth hormone-like activity

    Directory of Open Access Journals (Sweden)

    E. Khurtsidze

    2017-03-01

    Full Text Available Plant lectins are well documented to participate in multiple physiological activities based on selective binding to the carbohydrate structures. They have been reported to play significant roles in various processes such as growth and development, differentiation and plant protection. Nevertheless, the intrinsic roles of plant lectins still remain undefined. We purified a galactose-binding lectin, named MAL, from mulberry (M. alba L. seeds and analyzed its properties. The lectin is composed of one polypeptide of 17 kDa, which is abundant in the seed protein fraction. MAL interacted with GalNAc and galactose residues of saccharides with high binding ability. Western blotting analysis suggested that MAL is deposited in the mulberry leaves and inflorescence. MAL was examined for growth stimulatory activity on mulberry hypocotyls and internodal sections of in vitro grown P. euphratica cultures. Elongation of mulberry hypocotyls was detected in the apical parts of the hypocotyl, where the growth increment was 58%. MAL had no significant effect on the stem elongation and induction of new leaves. Our results suggest that MAL may be involved in the growth and cell elongation at initial stages of tissue development.

  16. Ulex europaeus I lectin induces activation of matrix-metalloproteinase-2 in endothelial cells.

    Science.gov (United States)

    Gomez, D E; Yoshiji, H; Kim, J C; Thorgeirsson, U P

    1995-11-02

    In this report, we show that the lectin Ulex europaeus agglutinin I (UEA I), which binds to alpha-linked fucose residues on the surface of endothelial cells, mediates activation of the 72-kDa matrix metalloproteinase-2 (MMP-2). A dose-dependent increase in the active 62-kDa form of MMP-2 was observed in conditioned medium from monkey aortic endothelial cells (MAEC) following incubation with concentrations of UEA I ranging from 2 to 100 micrograms/ml. The increase in the 62-kDa MMP-2 gelatinolytic activity was not reflected by a rise in MMP-2 gene expression. The UEA I-mediated activation of MMP-2 was blocked by L-fucose, which competes with UEA I for binding to alpha-fucose. These findings may suggest that a similar in vivo mechanism exists, whereby adhesive interactions between tumor cell lectins and endothelial cells can mediate MMP-2 activation.

  17. Characterization of the yam tuber storage proteins from Dioscorea batatas exhibiting unique lectin activities.

    Science.gov (United States)

    Gaidamashvili, Mariam; Ohizumi, Yuki; Iijima, Shinichiro; Takayama, Tomo; Ogawa, Tomohisa; Muramoto, Koji

    2004-06-18

    Four major proteins designated DB1, DB2, DB3, and DB4 were isolated and characterized from the yam tuber Dioscorea batatas. The ratios of their yields were 20:50:20:10. DB1 was a mannose-binding lectin (20 kDa) consisting of 10-kDa subunits and was classified as the monocot mannose-binding lectin family. DB2, accounting for 50% of the total protein, was the storage protein, commonly called dioscorins consisting of a 31-kDa subunit. On the basis of amino acid sequence, DB2 was classified to be dioscorin A. DB3 was a maltose-binding lectin, having an apparent molecular mass of 120 kDa and composed of a 66-kDa subunit and two 31-kDa subunits (DB3S). The 66-kDa subunit was further composed of two 31-kDa subunits (DB3L) cross-linked by disulfide bonds. DB3L and DB3S (242 and 241 amino acid residues, respectively) were homologous with each other with 72% sequence identity. They showed a sequence homology to dioscorin B and dioscorin A from Dioscorea alata, with 90 and 93% identity, respectively, and to carbonic anhydrase from Arabidopsis thaliana with about 45% identity. DB3S had one intrachain disulfide bond located at Cys(28)-Cys(187), whereas DB3L had one interchain disulfide bond (Cys(40)-Cys(40)') in addition to the intrachain disulfide bond (Cys(28)-Cys(188)) to form a 66-kDa subunit. DB1 and DB3 agglutinated rabbit erythrocytes at 2.7 and 3.9 microg/ml, respectively. Despite the structural homology between DB2 and DB3, DB2 had no lectin activity. The 66-kDa subunit itself revealed the full hemagglutinating activity of DB3, indicating that DB3L but not DB3S was responsible for the activity. The hemagglutinating activity of DB3 required Ca(2+) ions and was exclusively inhibited by maltose and oligomaltoses (e.g. maltopentaose and maltohexaose) but not by d-glucose. DB3 could not be classified into any known plant lectin family. DB4 was a chitinase, homologous to an acidic chitinase from Dioscorea japonica. DB1, DB2, and DB3 did not show any activity of carbonic

  18. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, Jens Christian; Christensen, I J

    2004-01-01

    BACKGROUND: Postoperative bacterial infectious complications are frequent in patients with colorectal cancer (CRC), with subsequent increased recurrence rates and poor prognosis. Deficiency of the mannan-binding lectin (MBL) complement activation pathway may cause increased risk of infection......: Serum MBL concentrations and MBL/MASP activity were determined using immunofluorometric assays. The levels are presented as the median, inter-quartile range and range. RESULTS: Serum MBL levels were significantly (P cancer (1384 (400-2188) ng/mL) (median...... in the colon or rectum, and disease stages according to Dukes' classification. No statistical difference (P=0.20) in frequency of MBL deficiency was found between the patients (20%) and the donors (27%). CONCLUSIONS: Overall, the MBL complement activation pathway is significantly increased in patients...

  19. The lectin pathway of complement activation is a critical component of the innate immune response to pneumococcal infection

    DEFF Research Database (Denmark)

    Ali, Youssif M; Lynch, Nicholas J; Haleem, Kashif S

    2012-01-01

    The complement system plays a key role in host defense against pneumococcal infection. Three different pathways, the classical, alternative and lectin pathways, mediate complement activation. While there is limited information available on the roles of the classical and the alternative activation...... to pneumococcal infection and fail to opsonize Streptococcus pneumoniae in the none-immune host. This defect in complement opsonisation severely compromises pathogen clearance in the lectin pathway deficient host. Using sera from mice and humans with defined complement deficiencies, we demonstrate that mouse...... of C4. This study corroborates the essential function of MASP-2 in the lectin pathway and highlights the importance of MBL-independent lectin pathway activation in the host defense against pneumococci....

  20. Plant Cell Protolytic Enzymes Activity under Exposure to Lectins of Endophytic and Epiphytic Azospirillum Strains

    Directory of Open Access Journals (Sweden)

    S.A. Alen’kina

    2016-05-01

    Full Text Available We studied the ability of lectins isolated from the surface of the two strains of nitrogen-fixing soil bacteria of the genus Azospirillum, A. brasilense Sp7 (epiphytic and A. brasilense Sp245 (endophytic, to show have a regulating effect on the activity of pectinolytic enzymes in the roots of wheat seedlings. Research results showed that the lectins under study can cause the induction of the activity of polygalacturonase, pectinesterase, pectatlyase from the plant cell wall, thereby ensuring the bacteria penetration in the plant tissues, as well as the induction of plants responses which, being combined with growth-stimulating effect of bacteria, contributes to the formation of plants stability and productivity.

  1. Enhanced visible light photocatalytic activity of g-C3N4 assisted by hydrogen peroxide

    Science.gov (United States)

    Chen, Quan-Liang; Liu, Yi-Ling; Tong, Li-Ge

    2018-04-01

    Water pollution has caused much attention nowadays. Photocatalysis as a kind of advanced oxidation technology has been widely studied in the field of environmental pollution control. As a stable non-metal photocatalyst, the photocatalytic activity of g-C3N4 assisted by H2O2 was investigated for the degradation of Rhodamine B (RhB) under visible light irradiation. The combination of g-C3N4 and H2O2 has much higher activity than that of pure g-C3N4 or H2O2. Neutral solution is preferred for the high phtotocatalytic activity of g-C3N4 with H2O2. The effect of the amount of catalyst, H2O2 concentration and RhB concentration was investigated. Photocatalytic mechanism study using radical scavenger showed free radicals {{{{O}}}2}- and · OH are the main active species. g-C3N4 assisted by H2O2 showed good photostability and repeatability after five cycles of degradation experiment.

  2. C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation.

    Science.gov (United States)

    Liu, Ying; Ye, Xuecheng; Jiang, Feng; Liang, Chunyang; Chen, Dongmei; Peng, Junmin; Kinch, Lisa N; Grishin, Nick V; Liu, Qinghua

    2009-08-07

    The catalytic engine of RNA interference (RNAi) is the RNA-induced silencing complex (RISC), wherein the endoribonuclease Argonaute and single-stranded small interfering RNA (siRNA) direct target mRNA cleavage. We reconstituted long double-stranded RNA- and duplex siRNA-initiated RISC activities with the use of recombinant Drosophila Dicer-2, R2D2, and Ago2 proteins. We used this core reconstitution system to purify an RNAi regulator that we term C3PO (component 3 promoter of RISC), a complex of Translin and Trax. C3PO is a Mg2+-dependent endoribonuclease that promotes RISC activation by removing siRNA passenger strand cleavage products. These studies establish an in vitro RNAi reconstitution system and identify C3PO as a key activator of the core RNAi machinery.

  3. Storage of the complement components C4, C3, and C 3-activator in the human liver as PAS-negative globular hyaline bodies.

    Science.gov (United States)

    Storch, W; Riedel, H; Trautmann, B; Justus, J; Hiemann, D

    1982-01-01

    Liver biopsies of a 58-year-old clinically healthy patient with a hepatomegaly and intracisternal PAS-negative globular hyaline bodies were immunofluorescent-optically examined for the content of the complement components C 1 q, C 4, C 9, C 1-inactivator, C 3-activator. Further examinations were performed for fibrinogen, IgG, IgA, IgM, IgD, IgE, L-chain (type chi and lambda), alpha 1-antitrypsin, alpha 1-fetoprotein, alpha 1- and alpha 2-glycoprotein, cholinesterase, ceruloplasmin, myoglobin, hemopexin, HBsAg and HBsAg. Th inclusion bodies reacted with antisera against the complement components C 4, C 3 and C 3-activator, as also identified by double immunofluorescence. Probably this is a disturbance of the protein metabolism of the liver cell with abnormal complement storage in the presence of normal total complement and normal complement components in the serum.

  4. Lectin histochemistry and alkaline phosphatase activity in the pia mater vessels of spontaneously hypertensive rats (SHR).

    Science.gov (United States)

    Szumańska, G; Gadamski, R

    1992-01-01

    Some lectins were used to study the localization of sugar residues on the endothelial cell surface in the pia mater blood vessels of control (WKY) and hypertensive rats (SHR). The lectins tested recognized the following residues: beta-D-galactosyl (Ricinus communis agglutinin 120, RCA-1), alpha-L-fucosyl (Ulex europaeus agglutinin, UEA-1), N-acetylglucosaminyl and sialyl (Wheat germ agglutinin, WGA), N-glycolyl-neuraminic acid (Limax flavus agglutinin, LFA), and N-acetyl-D-galactosaminyl (Helix pomatia agglutinin, HPA). Several differences were revealed in the presence of sugar receptors on the surface of endothelial cells between the control and the hypertensive rats. Our studies showed also differences in the localization of the tested glycoconjugates between pial capillaries, small, medium-size and large pial arteries. The histochemical evaluation of alkaline phosphatase revealed an increased activity of the enzyme in the pial vessels of SHRs as compared with control rats with a similar localization of the enzyme activity. Some differences in the distribution of lectin binding sites and alkaline phosphatase activity could be associated with the different functions of particular segments of the pial vascular network.

  5. Regulation of the activity of the promoter of RNA-induced silencing, C3PO.

    Science.gov (United States)

    Sahu, Shriya; Williams, Leo; Perez, Alberto; Philip, Finly; Caso, Giuseppe; Zurawsky, Walter; Scarlata, Suzanne

    2017-09-01

    RNA-induced silencing is a process which allows cells to regulate the synthesis of specific proteins. RNA silencing is promoted by the protein C3PO (component 3 of RISC). We have previously found that phospholipase Cβ, which increases intracellular calcium levels in response to specific G protein signals, inhibits C3PO activity towards certain genes. Understanding the parameters that control C3PO activity and which genes are impacted by G protein activation would help predict which genes are more vulnerable to downregulation. Here, using a library of 10 18 oligonucleotides, we show that C3PO binds oligonucleotides with structural specificity but little sequence specificity. Alternately, C3PO hydrolyzes oligonucleotides with a rate that is sensitive to substrate stability. Importantly, we find that oligonucleotides with higher Tm values are inhibited by bound PLCβ. This finding is supported by microarray analysis in cells over-expressing PLCβ1. Taken together, this study allows predictions of the genes whose post-transcriptional regulation is responsive to the G protein/phospholipase Cβ/calcium signaling pathway. © 2017 The Protein Society.

  6. Lectin binders

    International Nuclear Information System (INIS)

    Rudiger, H.; Gebauer, G.; Gansera, R.; Schurz, H.; Schimpl, A.

    1982-01-01

    Lectins are widely distributed in the plant kingdom, many of them being well characterized in their chemical structure and the effects they have on alien biological systems such as erythrocytes or lymphocytes. The biological function of plant lectins remains speculative. We therefore inspected plant extracts from components which might bind specifically to the lectin from the respective plant. Single proteins (lectin binders) could be isolated from each plant extract. The interaction of these proteins with lectins was demonstrated and qualified by several methods. Similar to the lectins, the lectin binders are localized in the cytoplasm in contrast to them, however, they persist during germination and plant growth. Their precise role in the plant is not known, but they are likely to be associated with lectins not only in vitro but also in vivo. They also interact with alien cells, and are able to stimulate mitosis in murine lymphocytes. Some lectin binders act specifically on B lymphocytes, leaving T cells uninfluenced

  7. Comparisons of labeling efficiency, biological activity and biodistribution among 125I, 67Ga-DTPA- and 67Ga-DFO-lectins

    International Nuclear Information System (INIS)

    Kojima, Shuji; Jay, M.

    1987-01-01

    The labeling efficiency, biological activity and biodistribution of 125 I labeled and 67 Ga chelating agent conjugated lectins were investigated. Pisum sativum agglutinin (PSA) and Lens culinaris agglutinin (LCH) were efficiently labeled with 67 Ga using bifunctional chelating agents such as diethylenetriaminepentaacetic acid (DTPA) and deferoxamine (DFO), whereas labeling with 125 I was significantly less efficient. The agglutinating activity of these lectins towards Ehrlich ascites tumor (EAT) cells was retained on conjugation with DFO, but not with DTPA. The in vitro binding ratio of 67 Ga-DFO-lectins for EAT cells was almost the same as that of 125 I-lectins. However, the value was significantly decreased in the case of 67 Ga-DTPA-lectins. In the biodistribution study of radiolabeled lectins in Ehrlich solid tumor (EST) bearing mice, the accumulation of radioactivity in tumor tissue was very much less with 67 Ga-DTPA-lectins than with 125 I-lectins. However, the concentration was significantly elevated in the case of 67 Ga-DFO-lectins. While, these lectins accumulated in liver, spleen, lung, and kidney to a greater extent than 67 Ga citrate, the tumor to organ ratios became very low. These low tumor to organ ratios, in contrast to 67 Ga citrate, will certainly inhibit the tumor delineation, and therefore it seems that in spite of a high accumulation ratio of 67 Ga-DFO-lectins in tumor tissue, these agents are not useful in tumor detection. (orig.)

  8. Deposition of mannose-binding lectin and ficolins and activation of the lectin pathway of complement on the surface of polyurethane tubing used for cardiopulmonary bypass.

    Science.gov (United States)

    Eppa, Łukasz; Pągowska-Klimek, Izabela; Świerzko, Anna S; Moll, Maciej; Krajewski, Wojciech R; Cedzyński, Maciej

    2018-04-01

    The artificial surface used for cardiopulmonary bypass (CPB) is a crucial factor activating the complement system and thus contributing to the generation of a systemic inflammatory response. The activation of classical and alternative pathways on this artificial surface is well known. In contrast, lectin pathway (LP) activation has not been fully investigated, although noted during CPB in several studies. Moreover, we have recently proved the contribution of the LP to the generation of the systemic inflammatory response syndrome after pediatric cardiac surgery. The aim of this study was to assess LP-mediated complement activation on the surface of polyurethane CPB circuit tubing (noncoated Chalice ® ), used for CPB procedures in children with congenital heart disease. We found deposition of mannose-binding lectin, ficolin-1, -2, and -3 on the surface of unused tubing and on tubing used for CPB from a small minority of patients. Furthermore, we observed deposition of complement C4 activation products on tubing used for CPB and previously unused tubing after incubation with normal serum. The latter finding indicates LP activation in vitro on the polyurethane surface. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1202-1208, 2018. © 2017 Wiley Periodicals, Inc.

  9. Bivalent Carbohydrate Binding Is Required for Biological Activity of Clitocybe nebularis Lectin (CNL), the N,N′-Diacetyllactosediamine (GalNAcβ1–4GlcNAc, LacdiNAc)-specific Lectin from Basidiomycete C. nebularis*

    Science.gov (United States)

    Pohleven, Jure; Renko, Miha; Magister, Špela; Smith, David F.; Künzler, Markus; Štrukelj, Borut; Turk, Dušan; Kos, Janko; Sabotič, Jerica

    2012-01-01

    Lectins are carbohydrate-binding proteins that exert their biological activity by binding to specific cell glycoreceptors. We have expressed CNL, a ricin B-like lectin from the basidiomycete Clitocybe nebularis in Escherichia coli. The recombinant lectin, rCNL, agglutinates human blood group A erythrocytes and is specific for the unique glycan N,N′-diacetyllactosediamine (GalNAcβ1–4GlcNAc, LacdiNAc) as demonstrated by glycan microarray analysis. We here describe the crystal structures of rCNL in complex with lactose and LacdiNAc, defining its interactions with the sugars. CNL is a homodimeric lectin, each of whose monomers consist of a single ricin B lectin domain with its β-trefoil fold and one carbohydrate-binding site. To study the mode of CNL action, a nonsugar-binding mutant and nondimerizing monovalent CNL mutants that retain carbohydrate-binding activity were prepared. rCNL and the mutants were examined for their biological activities against Jurkat human leukemic T cells and the hypersensitive nematode Caenorhabditis elegans mutant strain pmk-1. rCNL was toxic against both, although the mutants were inactive. Thus, the bivalent carbohydrate-binding property of homodimeric CNL is essential for its activity, providing one of the rare pieces of evidence that certain activities of lectins are associated with their multivalency. PMID:22298779

  10. Evaluation of lectin pathway activity and mannan-binding lectin levels in the course of pregnancy complicated by diabetes type 1, based on the genetic background.

    Science.gov (United States)

    Pertyńska Marczewska, Magdalena; Cedzyński, Maciej; Swierzko, Anna; Szala, Agnieszka; Sobczak, Małgorzata; Cypryk, Katarzyna; Wilczyński, Jan

    2009-01-01

    There are numerous indications that either mannan-binding lectin (MBL) deficiency or its excessive activity are associated with adverse pregnancy outcomes. High MBL concentrations and corresponding MBL2 genotypes were shown to be associated with microvascular complications in type 1 diabetes. The aim of this study was to evaluate levels of MBL and MBL-dependent activity of the lectin pathway (LP) of complement in the course of pregnancy in diabetic mothers, based on genetic background. These parameters were determined in samples from healthy non-pregnant (control), diabetic non-pregnant, healthy pregnant, and pregnant diabetic women. No significant differences in median MBL levels or LP activities were found in any study group compared to the control. However, statistically significant differences in MBL levels were noted during pregnancy between the 1st and 3rd trimesters in both healthy controls and pregnant diabetics. With regard to LP values, similar trends were evident, but statistically significant results were obtained only in the healthy pregnant group. When data analysis was confined to patients carrying the A/A (wild-type) MBL2 genotype, an increase in MBL level during pregnancy (in both healthy and diabetic pregnant women) was still observed. Similarly, LP activity increased during both healthy and diabetic pregnancies, significantly so for the former. Diabetes, an autoimmune disease, is a serious complication of pregnancy. Therefore, determination of MBL status might be beneficial in identifying type 1 diabetic patients who are at increased risk of developing both vascular complications and poor pregnancy outcomes.

  11. The evolution and appearance of C3 duplications in fish originate an exclusive teleost c3 gene form with anti-inflammatory activity.

    Directory of Open Access Journals (Sweden)

    Gabriel Forn-Cuní

    Full Text Available The complement system acts as a first line of defense and promotes organism homeostasis by modulating the fates of diverse physiological processes. Multiple copies of component genes have been previously identified in fish, suggesting a key role for this system in aquatic organisms. Herein, we confirm the presence of three different previously reported complement c3 genes (c3.1, c3.2, c3.3 and identify five additional c3 genes (c3.4, c3.5, c3.6, c3.7, c3.8 in the zebrafish genome. Additionally, we evaluate the mRNA expression levels of the different c3 genes during ontogeny and in different tissues under steady-state and inflammatory conditions. Furthermore, while reconciling the phylogenetic tree with the fish species tree, we uncovered an event of c3 duplication common to all teleost fishes that gave rise to an exclusive c3 paralog (c3.7 and c3.8. These paralogs showed a distinct ability to regulate neutrophil migration in response to injury compared with the other c3 genes and may play a role in maintaining the balance between inflammatory and homeostatic processes in zebrafish.

  12. The influence of gamma radiation upon the biological activity of the third serum complement component (C3)

    International Nuclear Information System (INIS)

    Steuhl, K.P.; Dierich, M.P.; Mainz Univ.

    1981-01-01

    For investigation of interaction between C3 and C3-binding cells the third complement component is to be labelled with radiotracer. After labelling C3 with high specific activity (0,2 μCi 125 l/μg C3) binding of C3 to Raji-cells was increased up to the twentyfold nine days after labelling. This effect was not to be reproduced with external gamma radiation using doses of 10, 200 and 1000 rad. The rosette inhibition test could demonstrate that with radiation doses of 200 and 1000 rad the radiated C3 lost its ability of specific binding to C3 receptors in Raji-cells. This functional alteration corresponded to amino acid analysis with relative increase of asparagine, glutamic acid and proline and relative decrease of cystine and phenylalanine in the C3 molecule. (orig.) [de

  13. LECTINS OF REPRESENTATIVES OF THE ECHINACEA GENUS (ECHINACEA MOENCH). 3. RESEARCH OF ACTIVITY IN ONTOGENESIS ECHINACEA PALLIDA (NUTT.) NUTT

    OpenAIRE

    Поспелов, Сергей Викторович

    2013-01-01

    For the first time research of dynamics of lectins activity of pale purple coneflower (Echinacea pallida (Nutt.) Nutt) in ontogenesis. It has been established that on the first year of vegetation the highest level of phytolectins observed in herbs at the second part of vegetation (14,0–16,0 point). In the roots with rhizomes lectins were appears only at the end of vegetation (up to 2,0 point). In the second year in the genesic period some high activity was observed of leave’s extracts at the ...

  14. Antitumor activity of the Korean mistletoe lectin is attributed to activation of macrophages and NK cells.

    Science.gov (United States)

    Yoon, Taek Joon; Yoo, Yung Choon; Kang, Tae Bong; Song, Seong Kyu; Lee, Kyung Bok; Her, Erk; Song, Kyung Sik; Kim, Jong Bae

    2003-10-01

    Inhibitory effect of the lectins (KML-C) isolated from Korean mistletoe (KM; Viscum album coloratum) on tumor metastases produced by murine tumor cells (B16-BL6 melanoma, colon 26-M3.1 carcinoma and L5178Y-ML25 lymphoma cells) was investigated in syngeneic mice. An intravenous (i.v.) administration of KML-C (20-50 ng/mouse) 2 days before tumor inoculation significantly inhibited lung metastases of both B16-BL6 and colon 26-M3.1 cells. The prophylactic effect of 50 ng/mouse of KML-C on lung metastasis was almost the same with that of 100 microg/mouse of KM. Treatment with KML-C 1 day after tumor inoculation induced a significant inhibition of not only the experimental lung metastasis induced by B16-BL6 and colon 26-M3.1 cells but also the liver and spleen metastasis of L5178Y-ML25 cells. Furthermore, multiple administration of KML-C given at 3 day-intervals after tumor inoculation led to a significant reduction of lung metastasis and suppression of the growth of B16-BL6 melanoma cells in a spontaneous metastasis model. In an assay for natural killer (NK) cell activity, i.v. administration of KML-C (50 ng/mouse) significantly augmented NK cytotoxicity against Yac-1 tumor cells 2 days after KML-C treatment. In addition, treatment with KML-C (50 ng/mouse) induced tumoricidal activity of peritoneal macrophages against B16-BL6 and 3LL cells. These results suggest that KML-C has an immunomodulating activity to enhance the host defense system against tumors, and that its prophylactic and therapeutic effect on tumor metastasis is associated with the activation of NK cells and macrophages.

  15. The cyanobacterial lectin scytovirin displays potent in vitro and in vivo activity against Zaire Ebola virus.

    Science.gov (United States)

    Garrison, Aura R; Giomarelli, Barbara G; Lear-Rooney, Calli M; Saucedo, Carrie J; Yellayi, Srikanth; Krumpe, Lauren R H; Rose, Maura; Paragas, Jason; Bray, Mike; Olinger, Gene G; McMahon, James B; Huggins, John; O'Keefe, Barry R

    2014-12-01

    The cyanobacterial lectin scytovirin (SVN) binds with high affinity to mannose-rich oligosaccharides on the envelope glycoprotein (GP) of a number of viruses, blocking entry into target cells. In this study, we assessed the ability of SVN to bind to the envelope GP of Zaire Ebola virus (ZEBOV) and inhibit its replication. SVN interacted specifically with the protein's mucin-rich domain. In cell culture, it inhibited ZEBOV replication with a 50% virus-inhibitory concentration (EC50) of 50 nM, and was also active against the Angola strain of the related Marburg virus (MARV), with a similar EC50. Injected subcutaneously in mice, SVN reached a peak plasma level of 100 nm in 45 min, but was cleared within 4h. When ZEBOV-infected mice were given 30 mg/kg/day of SVN by subcutaneous injection every 6h, beginning the day before virus challenge, 9 of 10 animals survived the infection, while all infected, untreated mice died. When treatment was begun one hour or one day after challenge, 70-90% of mice survived. Quantitation of infectious virus and viral RNA in samples of serum, liver and spleen collected on days 2 and 5 postinfection showed a trend toward lower titers in treated than control mice, with a significant decrease in liver titers on day 2. Our findings provide further evidence of the potential of natural lectins as therapeutic agents for viral infections. Published by Elsevier B.V.

  16. Ficolin-3-mediated lectin complement pathway activation in patients with subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Zanier, Elisa R; Zangari, Rosalia; Munthe-Fog, Lea

    2014-01-01

    OBJECTIVES: To assess the involvement of ficolin-3, the main initiator of the lectin complement pathway (LCP), in subarachnoid hemorrhage (SAH) pathology and outcome. METHODS: In this preliminary exploratory study, plasma concentration of ficolin-3 and of ficolin-3-mediated functional LCP activity...... the World Federation of Neurosurgical Societies grading scale; vasospasm, defined as neuro-worsening with angiographic confirmation of vessel narrowing; cerebral ischemia, defined as hypodense lesion on CT scan performed before discharge; and 6-month outcome, assessed using the Glasgow Outcome Scale....... RESULTS: In patients, no changes were detected for ficolin-3 compared with controls. Notably, however, ficolin-3-mediated functional LCP activity was reduced. Low levels of plasma ficolin-3 and ficolin-3-mediated functional LCP activity were related to SAH severity, vasospasm, and cerebral ischemia...

  17. Change in the Content of Salicylic Acid and in the Activities of Phenylalanine Ammonia-Lyase and Catalase in Wheat Seedling Roots Under the Effect of Azospirillum Lectins

    Directory of Open Access Journals (Sweden)

    Alen'kina S.A.

    2012-05-01

    Full Text Available We investigated the time course of changes in the endogenous content of salicylic acid, the ratio between the acid's free and bound forms, and changes in the activities of phenylalanine ammonia-lyase and catalase in wheat seedling roots under the effect of the lectins of two strains of the associative nitrogen-fixing bacterium Azospirillum: A. brasilense Sp7 and its mutant defective in lectin activity, A. brasilense Sp7.2.3. Differences in plant response to the action of the lectins from these two strains were established. On the basis of the obtained data, a model was proposed for lectin-assisted induction of resistance, according to which the lectin effect on the roots of seedlings results in accumulation of free salicylic acid, which inhibits catalase activity, ultimately leading to accumulation of hydrogen peroxide and to formation of induced resistance.

  18. Binding properties of a blood group Le(a+) active sialoglycoprotein, purified from human ovarian cyst, with applied lectins.

    Science.gov (United States)

    Wu, A M; WU, J H; Watkins, W M; Chen, C P; Tsai, M C

    1996-06-07

    Studies on the structures and binding properties of the glycoproteins, purified from human ovarian cyst fluids, will aid the understanding of the carbohydrate alterations occurring during the biosynthesis of blood group antigens and neoplasm formation. These glycoproteins can also serve as important biological materials to study blood group A, B, H, Le(a), Le(b), Le(x), Le(y), T and Tn determinants, precursor type I and II sequences and cold agglutinin I and i epitopes. In this study, the binding property of a cyst glycoprotein from a human blood group Le(a+) nonsecretor individual, that contains an unusually high amount (18%) of sialic acid (HOC 350) was characterized by quantitative precipitin assay with a panel of lectins exhibiting a broad range of carbohydrate-binding specificities. Native HOC 350 reacted well only with three out of nineteen lectins tested. It precipitated about 80% of Ricinus communis (RCA1), 50% of Triticum vulgaris (WGA) and 37% of Bauhinia purpurea aba (BPA) agglutinins, respectively. However, its asialo product had dramatically enhanced reactivity and reacted well with many I/II (Gal beta1 --> 3/4GcNAc), T(Gal beta1 --> 3GalNAc) and Tn(GaNIAc alphaI --> Ser/Thr) active lectins. It bound best to Jacalin, BPA, and abrin-a and completely precipitated all the lectins added. Asialo-HOC 350 also reacted strongly with Wistaria floribunda, Abrus precatorius agglutinin, ricin and RCA1 and precipitated over 75% of the lectin nitrogen added, and moderately with Arachis hypogaea, Maclura pomifera, WGA, Vicia viosa-B4, Codium fragile tomentosoides and Ulex europaeus-II. But native HOC 350 and its asialo product reacted not at all or poorly with Dolichos biflorus, Helix pomatia, Lotus tetra-gonolobus, Ulex europaeus-I, Lens culinaris lectins and Con A. The lectin-glycoform interactions through bioactive sugars were confirmed by precipitin inhibition assay. Mapping the precipitation profiles of the interactions have led to the conclusion that HOC 350

  19. Identification and Biological Activity of Synthetic Macrophage Inducible C-Type Lectin Ligands

    Directory of Open Access Journals (Sweden)

    Chriselle D. Braganza

    2018-01-01

    Full Text Available The macrophage inducible C-type lectin (Mincle is a pattern recognition receptor able to recognize both damage-associated and pathogen-associated molecular patterns, and in this respect, there has been much interest in determining the scope of ligands that bind Mincle and how structural modifications to these ligands influence ensuing immune responses. In this review, we will present Mincle ligands of known chemical structure, with a focus on ligands that have been synthetically prepared, such as trehalose glycolipids, glycerol-based ligands, and 6-acylated glucose and mannose derivatives. The ability of the different classes of ligands to influence the innate, and consequently, the adaptive, immune response will be described, and where appropriate, structure–activity relationships within each class of Mincle ligands will be presented.

  20. Lectins from Mycelia of Basidiomycetes

    Directory of Open Access Journals (Sweden)

    Valentina E. Nikitina

    2017-06-01

    Full Text Available Lectins are proteins of a nonimmunoglobulin nature that are capable of specific recognition of and reversible binding to the carbohydrate moieties of complex carbohydrates, without altering the covalent structure of any of the recognized glycosyl ligands. They have a broad range of biological activities important for the functioning of the cell and the whole organism and, owing to the high specificity of reversible binding to carbohydrates, are valuable tools used widely in biology and medicine. Lectins can be produced by many living organisms, including basidiomycetes. Whereas lectins from the fruit bodies of basidiomycetes have been studied sufficiently well, mycelial lectins remain relatively unexplored. Here, we review and comparatively analyze what is currently known about lectins isolated from the vegetative mycelium of macrobasidiomycetes, including their localization, properties, and carbohydrate specificities. Particular attention is given to the physiological role of mycelial lectins in fungal growth and development.

  1. Differential activity of a lectin from Solieria filiformis against human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    M.L. Holanda

    2005-12-01

    Full Text Available A lectin isolated from the red alga Solieria filiformis was evaluated for its effect on the growth of 8 gram-negative and 3 gram-positive bacteria cultivated in liquid medium (three independent experiments/bacterium. The lectin (500 µg/mL stimulated the growth of the gram-positive species Bacillus cereus and inhibited the growth of the gram-negative species Serratia marcescens, Salmonella typhi, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus sp, and Pseudomonas aeruginosa at 1000 µg/mL but the lectin (10-1000 µg/mL had no effect on the growth of the gram-positive bacteria Staphylococcus aureus and B. subtilis, or on the gram-negative bacteria Escherichia coli and Salmonella typhimurium. The purified lectin significantly reduced the cell density of gram-negative bacteria, although no changes in growth phases (log, exponential and of decline were observed. It is possible that the interaction of S. filiformis lectin with the cell surface receptors of gram-negative bacteria promotes alterations in the flow of nutrients, which would explain the bacteriostatic effect. Growth stimulation of the gram-positive bacterium B. cereus was more marked in the presence of the lectin at a concentration of 1000 µg/mL. The stimulation of the growth of B. cereus was not observed when the lectin was previously incubated with mannan (125 µg/mL, its hapten. Thus, we suggest the involvement of the binding site of the lectin in this effect. The present study reports the first data on the inhibition and stimulation of pathogenic bacterial cells by marine alga lectins.

  2. Self-assembled hierarchical carbon/g-C3N4 composite with high photocatalytic activity

    Science.gov (United States)

    Huang, Ru-Long; Huang, Wei-Qing; Li, Dong-Feng; Ma, Li-Li; Pan, Anlian; Hu, Wangyu; Fan, Xiaoxing; Huang, Gui-Fang

    2018-04-01

    Hierarchical carbon/g-C3N4 composites consisting of nanosheets are synthesized by a direct thermal diffusion and exfoliation approach with glucose acting as the intercalator and carbon source. This facile protocol not only renders nanosheets with a large surface area, but also carbon intercalation into the interlayer of g-C3N4. Therefore, the synthesized carbon/g-C3N4 composites exhibit superior photocatalytic performance for degrading representative methylene blue (MB) under visible light irradiatuon. Carbon/g-C3N4 composites with an optimal glucose mass ratio of 0.25% show the apparent reaction rate constant of 0.253 h-1, which is 9 times higher than that over bluk g-C3N4. The superior photocatalytic performance of carbon/g-C3N4 hierarchical architectures can be attributed to the synergic effects of large reactive sites, effective visible light adsorption and faster charge transfer owing to the superior electron transfer ability of carbon as verified by the PL and photoelectrochemical measurements. The main reactive species responsible for the photocatalytic degradation are photoinduced holes and ·OH radicals under visible light irradiation. This work provides a facile way to fabricate effecient g-C3N4-based photocatalysts for the potential application in dealing with environmental and energy shortage issues using solar energy.

  3. Two acid RNases from Dactylis glomerata seeds. Purification, properties and effect of polyamines and lectins on their activity

    Directory of Open Access Journals (Sweden)

    Janina Wiśniowska

    2014-01-01

    Full Text Available Two glycoproteidic acid RNases (RNase I and RNase II were obtained and purified from the seeds of Dactylis glomerata by extraction with acetate buffer, fractionation with ammonium sulfate, ion-exchange chromatography on DEAE-cellulose, DEAE-Sphadex, affinity chromatography on Con A-Sepharose and gel filtration on Bio-Gel P60. RNase I with a specific activity of 2582 U•mg-1 protein and an optimum pH of 4.9 and RNase II with a specific activity of 1928 U• mg-1 protein and optimum pH of 4.6, were isolated. They lacked nuclease, phosphodi- and monoesterase activities. Both forms of the enzyme hydrolyzed pyrimidine homopolymers with a preference for poly U and exhibited a low specificity for purine homopolymers (poly G and poly A. RNase I acted with a 3-fold higher hydrolytic activity on poly C homopolymer than RNase IL The hydrolytic activity of both enzymes was inhibited by Zn+2, Fe+2, Cu+2 ions when yeast RNA was the substrate. The amines spermine, spermidine and tyramine at a concentration of 0.1 mM increased the enzymatic activity of both RNases by 20 to 60% of the relative activity. The hydrolytic activity of RNases I and II was stimulated by the presence of lentil lectin (LL, soybean lectin (SBA and potato lectin (STA, and inhibited by the presence of concanavalin A. The 20-200% stimulation and 40-60% inhibition depended on the proportion, on a weight basis, of enzyme to lectin and were reversible in the presence of receptor sugars.

  4. Photocatalytic C-H Activation and Oxidative Esterification Using Pd@g-C3N4

    Data.gov (United States)

    U.S. Environmental Protection Agency — Graphitic carbon nitride supported palladium nanoparticles, Pd@g-C3N4, have been synthesized and utilized for the direct oxidative esterification of alcohols using...

  5. Photocatalytic C−H Activation of Hydrocarbons over VO@g‑C3N4

    Data.gov (United States)

    U.S. Environmental Protection Agency — A highly selective and sustainable method has been developed for the oxidation of methyl arenes and their analogues. The VO@g-C3N4 catalyst is very efficient in the...

  6. Purification of a novel chitin-binding lectin with antimicrobial and antibiofilm activities from a bangladeshi cultivar of potato (Solanum tuberosum).

    Science.gov (United States)

    Hasan, Imtiaj; Ozeki, Yasuhiro; Kabir, Syed Rashel

    2014-04-01

    A new chitin-binding lectin was purified from a Bangladeshi cultivar 'Deshi' of potato (Solanum tuberosum L.) through anion-exchange and affinity chromatographies using a chitin column. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed the molecular mass of the lectin as 20,000 Daltons. This molecular mass was almost half of the molecular masses of chitin-binding lectins derived from other potatoes. The lectin showed both bactericidal and growth-inhibiting activities against Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli, Salmonella enteritidis and Shigella boydii) pathogenic bacteria. It also showed antifungal activity against Rhizopus spp., Penicillium spp. and Aspergillus niger. Biofilm produced by the bacterium Pseudomonas aeruginosa was dose-dependently reduced by 5-20% in 24 h after administration of the lectin, which was attributed to the glycan-binding property of the lectin having affinity to GlcNAc polymers. It was the first observation that any potato lectin prevented biofilm formation by P. aeruginosa and, therefore, could have possible applications in clinical microbiology and biomedical science.

  7. Regulation of C3 Activation by the Alternative Complement Pathway in the Mouse Retina.

    Directory of Open Access Journals (Sweden)

    Jennifer A E Williams

    Full Text Available The purpose of this study was to examine the retinas of mice carrying hemizygous and null double deletions of Cfb-/- and Cfh-/-, and to compare these with the single knockouts of Cfb, Cfh and Cfd. Retinas were isolated from wild type (WT, Cfb-/-/Cfh-/-, Cfb-/-/Cfh+/-, Cfh-/-/Cfb+/-, Cfb-/-, Cfh-/- Cfd-/-, and Cfd+/- mice. Complement proteins were evaluated by western blotting, ELISA and immunocytochemistry, and retinal morphology was assessed using toluidine blue stained semi-thin sections. WT mice showed staining for C3 and its breakdown products in the retinal vasculature and the basal surface of the retinal pigment epithelium (RPE. Cfb-/- mice exhibited a similar C3 staining pattern to WT in the retinal vessels but a decrease in C3 and its breakdown products at the basal surface of the RPE. Deletion of both Cfb and Cfh restored C3 to levels similar to those observed in WT mice, however this reversal of phenotype was not observed in Cfh-/-/Cfb+/- or Cfb-/-/Cfh+/- mice. Loss of CFD caused an increase in C3 and a decrease in C3 breakdown products along the basal surface of the RPE. Overall the retinal morphology and retinal vasculature did not appear different across the various genotypes. We observed that C3 accumulates at the basal RPE in Cfb-/-, Cfb-/-/Cfh-/-, Cfb-/-/Cfh+/-, Cfd-/- and WT mice, but is absent in Cfh-/- and Cfh-/-/Cfb+/- mice, consistent with its consumption in the serum of mice lacking CFH when CFB is present. C3 breakdown products along the surface of the RPE were either decreased or absent when CFB, CFH or CFD was deleted or partially deleted.

  8. Facile synthesis of graphitic C3N4 nanoporous-tube with high enhancement of visible-light photocatalytic activity

    Science.gov (United States)

    Zhao, Ruiru; Gao, Jianping; Mei, Shunkang; Wu, Yongli; Wang, Xiaoxue; Zhai, Xiangang; Yang, Jiangbing; Hao, Chaoyue; Yan, Jing

    2017-12-01

    A simple and convenient method was used to synthesize a graphitic carbon nitride (g-C3N4) nanoporous-tube by using SiO2 nanoparticles as pore formers. The structure of the g-C3N4 nanoporous-tube was characterized by the SEM and TEM images. Taking photodegradation of RhB as an example, the photocatalytic activity of the as-prepared g-C3N4 nanoporous-tube was investigated. It can photodegrade 90% RhB in 40 min under visible-light irradiation and obtain a k value of 0.04491 min-1, which is 8.16 times that of bulk g-C3N4, 3.09 times that of tubular g-C3N4 and 1.48 times that of tubular g-C3N4-SiO2. The significant enhancement in photocatalytic efficiency is due to the edge effect of the pores and the special structure of the tubes. In addition, the possible mechanism of photocatalytic degradation of RhB was also proposed based on the trapping experiment of active species, which indicated that the superoxide radicals ({{{{O}}}2}\\bullet -) and the holes (h +) were the main reactive species in this photocatalyst. This work may open up a new idea of innovation in g-C3N4 structure and inspire its follow-up study.

  9. Global Autorecognition and Activation of Complement by Mannan-Binding Lectin in a Mouse Model of Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Esben Axelgaard

    2017-01-01

    Full Text Available Increasing evidence links mannan-binding lectin (MBL to late vascular complications of diabetes. MBL is a complement-activating pattern recognition molecule of the innate immune system that can mediate an inflammation response through activation of the lectin pathway. In two recent animal studies, we have shown that autoreactivity of MBL is increased in the kidney in diabetic nephropathy. We hypothesize that long-term exposure to uncontrolled high blood glucose in diabetes may mediate formation of neoepitopes in several tissues and that MBL is able to recognize these structures and thus activate the lectin pathway. To test this hypothesis, we induced diabetes by injection of low-dose streptozotocin in MBL double-knockout (MBL/DKO mice. Development of diabetes was followed by measurements of blood glucose and urine albumin-to-creatinine ratio. Fluorophore-labelled recombinant MBL was injected intravenously in diabetic and nondiabetic mice followed by ex vivo imaging of several organs. We observed that MBL accumulated in the heart, liver, brain, lung, pancreas, and intestines of diabetic mice. We furthermore detected increased systemic complement activation after administration of MBL, thus indicating MBL-mediated systemic complement activation in these animals. These new findings indicate a global role of MBL during late diabetes-mediated vascular complications in various tissues.

  10. Oviposition-stimulant and ovicidal activities of Moringa oleifera lectin on Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Nataly Diniz de Lima Santos

    Full Text Available Natural insecticides against the vector mosquito Aedes aegypti have been the object of research due to their high level of eco-safety. The water-soluble Moringa oleifera lectin (WSMoL is a larvicidal agent against A. aegypti. This work reports the effects of WSMoL on oviposition and egg hatching of A. aegypti.WSMoL crude preparations (seed extract and 0-60 protein fraction, at 0.1 mg/mL protein concentration, did not affect oviposition, while A. aegypti gravid females laid their eggs preferentially (73% in vessels containing isolated WSMoL (0.1 mg/mL, compared with vessels containing only distilled water (control. Volatile compounds were not detected in WSMoL preparation. The hatchability of fresh eggs deposited in the solutions in the oviposition assay was evaluated. The numbers of hatched larvae in seed extract, 0-60 protein fraction and WSMoL were 45 ± 8.7 %, 20 ± 11 % and 55 ± 7.5 %, respectively, significantly (p<0.05 lower than in controls containing only distilled water (75-95%. Embryos were visualized inside fresh control eggs, but not within eggs that were laid and maintained in WSMoL solution. Ovicidal activity was also assessed using stored A. aegypti eggs. The protein concentrations able to reduce the hatching rate by 50% (EC50 were 0.32, 0.16 and 0.1 mg/mL for seed extract, 0-60 protein fraction and WSMoL, respectively. The absence of hatching of stored eggs treated with WSMoL at 0.3 mg/mL (EC99 after transfer to medium without lectin indicates that embryos within the eggs were killed by WSMoL. The reduction in hatching rate of A. aegypti was not linked to decrease in bacteria population.WSMoL acted both as a chemical stimulant cue for ovipositing females and ovicidal agent at a given concentration. The oviposition-stimulant and ovicidal activities, combined with the previously reported larvicidal activity, make WSMoL a very interesting candidate in integrated A. aegypti control.

  11. Heterocomplexes of mannose-binding lectin and the pentraxins PTX3 or SAP trigger cross-activation of the complement system

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Doni, Andrea; Skjødt, Mikkel-Ole

    2011-01-01

    The long pentraxin 3 (PTX3), serum amyloid P component (SAP) and C-reactive protein (CRP) belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via...... the analogous mannose-binding lectin (MBL) from the lectin complement pathway is unknown. Thus, we investigated the possible interaction between MBL and the pentraxins. We report that MBL bound PTX3 and SAP partly via its collagen-like domain, but not CRP. MBL:PTX3 complex formation resulted in recruitment of C......1q, but this was not seen for the MBL:SAP complex. However, both MBL:PTX3 and MBL:SAP complexes enhanced C4 and C3 deposition and opsonophagocytosis of Candida albicans by polymorphonuclear leukocytes. Interaction between MBL and PTX3 lead to communication between the lectin and classical complement...

  12. Synthesis and enhanced photocatalytic activity of g-C3N4 ...

    Indian Academy of Sciences (India)

    2017-12-06

    Dec 6, 2017 ... sents an easy method to utilize the energy of either artifi- cial illumination or natural ... light. In this work, we reported the synthesis of the C3N4/CdS ... Compared ... The above suspension was stirred in the dark before irradi-.

  13. Mannose-binding lectin impairs Leptospira activity through the inhibitory effect on the motility of cell.

    Science.gov (United States)

    Xu, Jun; Guo, Yijie; Nakamura, Shuichi; Islam, Md Shafiqul; Tomioka, Rintaro; Yoneyama, Hiroshi; Isogai, Emiko

    2015-02-01

    Mannose-binding lectin (MBL) plays key role in lectin pathway of innate immunity, and shows the ability of triggering opsonization intermediately. Substantial increase in the serum level of MBL has been confirmed during leptospirosis, which caused by a pathogenic spirochete, Leptospira. Leptospira has a fascinating locomotion pattern, which simultaneously gyrating and swimming forward, such motility enables that Leptospira is difficult to be captured by immune cells if without any assistance. In this study, the effect of mannose-binding lectin to Leptospira was quantitatively investigated by measuring some kinematic parameters, to discover the mechanism behind MBL-mediated immune responses during leptospiral infection. The results showed that mannose-binding lectin is capable of inhibiting the motility of Leptospira by transforming free swimming cells to tumbled rotating cells, resulted in the increase number of rotating cells. Otherwise, decrease in rotation rate of rotating cell has been observed. However, the swimming speed of swimming Leptospira cells showed no observable change under the effect of MBL. The inhibitory effect were only valid in a relatively short period, Leptospira cells regained their original motility after 2 h. This raises an interesting topic that Leptospira is somehow able to escape from the inhibitory effect of MBL by dragging such unfavorable molecules toward to the cell end and eventually throwing it out. The inhibitory effect of MBL on the motility of Leptospira is expected to provide a new insight into lectin pathway. Copyright © 2015 Elsevier GmbH. All rights reserved.

  14. The search for lectin isolated from the mycelial cultures of Laetiporus sulphureus

    Directory of Open Access Journals (Sweden)

    Grażyna Końska

    2014-08-01

    Full Text Available This study proved the presence of lectin in mycelial cultures of Laetiporus sulphureus. Lectin was excreted into the medium and its erythroagglutinating activity was not high. No active lectin was detected in hyphae using both extraction and immunofluorescence method. Comparative studies based on immunological methods indicate~ that the lectin synthesised in vitro differed from the lectin produced in fruit-bodies.

  15. Depressed activation of the lectin pathway of complement in hereditary angioedema

    DEFF Research Database (Denmark)

    Varga, L; Széplaki, G; Laki, J

    2008-01-01

    ) in three complement activation pathways. Functional activity of the CP, LP and AP were measured in the sera of 68 adult patients with hereditary angioedema (HAE) and 64 healthy controls. In addition, the level of C1q, MBL, MBL-associated serine protease-2 (MASP-2), C4-, C3- and C1INH was measured...... by standard laboratory methods. MBL-2 genotypes were determined by polymerase chain reaction. Besides the complement alterations (low CP and C1INH activity, low C4-, C1INH concentrations), which characterize HAE, the level of MASP-2 was also lower (P = 0.0001) in patients compared with controls. Depressed LP...

  16. Assessing biosafety of GM plants containing lectins

    DEFF Research Database (Denmark)

    Poulsen, Morten; Pedersen, Jan W.

    2010-01-01

    insects. However, since the cry genes are not active against all insects, e.g. sap-sucking insects, other genes coding for proteins such as lectins show promise of complementing the cry genes for insect resistance. As with other novel plants, lectin-expressing plants will need to be assessed...... for their potential risks to human and animal health and the environment. The expressed lectin protein should be assessed on its own for potential toxicity and allergenicity as for any other new protein. Although not many lectins have been thoroughly tested for their toxicity, our evaluation suggests that most...... of the lectins that are potentially useful for insect resistance will pose no health risk in genetically modified (GM) plants. Since some lectins are known for their toxicity to humans, the insertion of lectin genes in food crop plants will have to be assessed carefully. It is expected that in some cases...

  17. Feline Lectin Activity Is Critical for the Cellular Entry of Feline Infectious Peritonitis Virus▿

    OpenAIRE

    Regan, Andrew D.; Ousterout, David G.; Whittaker, Gary R.

    2010-01-01

    Feline infectious peritonitis is a lethal disease of felids caused by systemic infection with a feline coronavirus. Here, we report identification and analysis of the feline homologue to the human lectin DC-SIGN and show that it is a coreceptor for virulent strains of serotype 1 and serotype 2 feline coronaviruses.

  18. A mannose-specific tetrameric lectin with mitogenic and antibacterial activities from the ovary of a teleost, the cobia (Rachycentron canadum).

    Science.gov (United States)

    Ngai, Patrick H K; Ng, T B

    2007-02-01

    A tetrameric lectin, with hemagglutinating activity toward rabbit erythrocytes and with specificity toward D-mannosamine and D(+)-mannose, was isolated from the ovaries of a teleost, the cobia Rachycentron canadum. The isolation protocol comprised ion exchange chromatography on CM-cellulose and Q-Sepharose, ion exchange chromatography by fast protein liquid chromatography (FPLC) on Mono Q, and finally gel filtration by FPLC on Superose 12. The lectin was adsorbed on all ion exchangers used. It exhibited a molecular mass of 180 kDa in gel filtration on Superose 12 and a single 45-kDa band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that it is a tetrameric protein. The hemagglutinating activity of the lectin was stable up to 40 degrees C and between pH 4 and pH 10. All hemagglutinating activity disappeared at 60 degrees C and at pH 1 and pH 13. The hemagglutinating activity was doubled in the presence of 0.1 microM FeCl3. The lectin exerted antibacterial activity against Escherichia coli with 50% inhibition at 250 microg. There was no antifungal activity toward Coprinus comatus, Fusarium oxysporum, Mycosphaerella arachidicola, and Rhizoctonia solani at a dose of 300 microg. The lectin exhibited maximal mitogenic response from mouse splenocytes at a concentration of 14 microM.

  19. A Novel Lectin with Antiproliferative and HIV-1 Reverse Transcriptase Inhibitory Activities from Dried Fruiting Bodies of the Monkey Head Mushroom Hericium erinaceum

    Science.gov (United States)

    Li, Yanrui; Zhang, Guoqing; Ng, Tzi Bun; Wang, Hexiang

    2010-01-01

    A lectin designated as Hericium erinaceum agglutinin (HEA) was isolated from dried fruiting bodies of the mushroom Hericium erinaceum with a chromatographic procedure which entailed DEAE-cellulose, CM-cellulose, Q-Sepharose, and FPLC Superdex 75. Its molecular mass was estimated to be 51 kDa and its N-terminal amino acid sequences was distinctly different from those of other isolated mushroom lectins. The hemagglutinating activity of HEA was inhibited at the minimum concentration of 12.5 mM by inulin. The lectin was stable at pH 1.9–12.1 and at temperatures up to 70°C, but was inhibited by Hg2+, Cu2+, and Fe3+ ions. The lectin exhibited potent mitogenic activity toward mouse splenocytes, and demonstrated antiproliferative activity toward hepatoma (HepG2) and breast cancer (MCF7) cells with an IC50 of 56.1 μM and 76.5 μM, respectively. It manifested HIV-1 reverse transcriptase inhibitory activity with an IC50 of 31.7 μM. The lectin exhibited potent mitogenic activity toward murine splenocytes but was devoid of antifungal activity. PMID:20625408

  20. A Novel Lectin with Antiproliferative and HIV-1 Reverse Transcriptase Inhibitory Activities from Dried Fruiting Bodies of the Monkey Head Mushroom Hericium erinaceum

    Directory of Open Access Journals (Sweden)

    Yanrui Li

    2010-01-01

    Full Text Available A lectin designated as Hericium erinaceum agglutinin (HEA was isolated from dried fruiting bodies of the mushroom Hericium erinaceum with a chromatographic procedure which entailed DEAE-cellulose, CM-cellulose, Q-Sepharose, and FPLC Superdex 75. Its molecular mass was estimated to be 51 kDa and its N-terminal amino acid sequences was distinctly different from those of other isolated mushroom lectins. The hemagglutinating activity of HEA was inhibited at the minimum concentration of 12.5 mM by inulin. The lectin was stable at pH 1.9–12.1 and at temperatures up to 70∘C, but was inhibited by Hg2+, Cu2+, and Fe3+ ions. The lectin exhibited potent mitogenic activity toward mouse splenocytes, and demonstrated antiproliferative activity toward hepatoma (HepG2 and breast cancer (MCF7 cells with an IC50 of 56.1 M and 76.5 M, respectively. It manifested HIV-1 reverse transcriptase inhibitory activity with an IC50 of 31.7 M. The lectin exhibited potent mitogenic activity toward murine splenocytes but was devoid of antifungal activity.

  1. Targeting of macrophage galactose-type C-type lectin (MGL) induces DC signaling and activation

    DEFF Research Database (Denmark)

    Napoletano, Chiara; Zizzari, Ilaria G; Rughetti, Aurelia

    2012-01-01

    NAc or Tn)-carrying tumor-associated antigens to improve DC performance. MGL expressed by ex vivo-generated iDCs from healthy donors was engaged by a 60-mer MUC1(9Tn) -glycopeptide as a Tn-carrying tumor-associated antigen, and an anti-MGL antibody, as a specific MGL binder. We demonstrated that MGL......Dendritic cells (DCs) sense the microenvironment through several types of receptors recognizing pathogen-associated molecular patterns. In particular, C-type lectins, expressed by distinct subsets of DCs, recognize and internalize specific carbohydrate antigen in a Ca(2+) -dependent manner....... Targeting of these receptors is becoming an efficient strategy of delivering antigens in DC-based anticancer immunotherapy. Here we investigated the role of the macrophage galactose type C-lectin receptor (MGL), expressed by immature DCs (iDCs), as a molecular target for a-N-acetylgalactosamine (Gal...

  2. Broad anti-HIV activity of the Oscillatoria agardhii agglutinin homologue lectin family.

    Science.gov (United States)

    Férir, Geoffrey; Huskens, Dana; Noppen, Sam; Koharudin, Leonardus M I; Gronenborn, Angela M; Schols, Dominique

    2014-10-01

    Oscillatoria agardhii agglutinin homologue (OAAH) proteins belong to a recently discovered lectin family. The founding member OAA and a designed hybrid OAAH (OPA) recognize similar but unique carbohydrate structures of Man-9, compared with other antiviral carbohydrate-binding agents (CBAs). These two newly described CBAs were evaluated for their inactivating properties on HIV replication and transmission and for their potential as microbicides. Various cellular assays were used to determine antiviral activity against wild-type and certain CBA-resistant HIV-1 strains: (i) free HIV virion infection in human T lymphoma cell lines and PBMCs; (ii) syncytium formation assay using persistently HIV-infected T cells and non-infected CD4+ T cells; (iii) DC-SIGN-mediated viral capture; and (iv) transmission to uninfected CD4+ T cells. OAA and OPA were also evaluated for their mitogenic properties and potential synergistic effects using other CBAs. OAA and OPA inhibit HIV replication, syncytium formation between HIV-1-infected and uninfected T cells, DC-SIGN-mediated HIV-1 capture and transmission to CD4+ target T cells, thereby rendering a variety of HIV-1 and HIV-2 clinical isolates non-infectious, independent of their coreceptor use. Both CBAs competitively inhibit the binding of the Manα(1-2)Man-specific 2G12 monoclonal antibody (mAb) as shown by flow cytometry and surface plasmon resonance analysis. The HIV-1 NL4.3(2G12res), NL4.3(MVNres) and IIIB(GRFTres) strains were equally inhibited as the wild-type HIV-1 strains by these CBAs. Combination studies indicate that OAA and OPA act synergistically with Hippeastrum hybrid agglutinin, 2G12 mAb and griffithsin (GRFT), with the exception of OPA/GRFT. OAA and OPA are unique CBAs with broad-spectrum anti-HIV activity; however, further optimization will be necessary for microbicidal application. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights

  3. The mannan-binding lectin pathway of complement activation: biology and disease association

    DEFF Research Database (Denmark)

    Petersen, Steen Vang; Thiel, S; Jensenius, J C

    2001-01-01

    Mannan-binding lectin (MBL) is a plasma protein found in association with several serine proteases (MASPs) forming the MBL complex. MBL recognises carbohydrate structures arranged in a particular geometry, such as those found on the surface of micro-organisms. When bound to e.g. bacteria the MBL...... as an initiator of the host response against potential pathogenic micro-organisms. Udgivelsesdato: 2001-Aug...

  4. Comparative study of anti-angiogenic activities of luteolin, lectin and lupeol biomolecules.

    Science.gov (United States)

    Ambasta, Rashmi K; Jha, Saurabh Kumar; Kumar, Dhiraj; Sharma, Renu; Jha, Niraj Kumar; Kumar, Pravir

    2015-09-18

    Angiogenesis is a hallmark feature in the initiation, progression and growth of tumour. There are various factors for promotion of angiogenesis on one hand and on the other hand, biomolecules have been reported to inhibit cancer through anti-angiogenesis mechanism. Biomolecules, for instance, luteolin, lectin and lupeol are known to suppress cancer. This study aims to compare and evaluate the biomolecule(s) like luteolin, lupeol and lectin on CAM assay and HT-29 cell culture to understand the efficacy of these drugs. The biomolecules have been administered on CAM assay, HT-29 cell culture, cell migration assay. Furthermore, bioinformatics analysis of the identified targets of these biomolecules have been performed. Luteolin has been found to be better in inhibiting angiogenesis on CAM assay in comparison to lupeol and lectin. In line with this study when biomolecules was administered on cell migration assay via scratch assay method. We provided evidence that Luteolin was again found to be better in inhibiting HT-29 cell migration. In order to identify the target sites of luteolin for inhibition, we used software analysis for identifying the best molecular targets of luteolin. Using software analysis best target protein molecule of these biomolecules have been identified. VEGF was found to be one of the target of luteolin. Studies have found several critical point mutation in VEGF A, B and C. Hence docking analysis of all biomolecules with VEGFR have been performed. Multiple allignment result have shown that the receptors are conserved at the docking site. Therefore, it can be concluded that luteolin is not only comparatively better in inhibiting blood vessel in CAM assay, HT-29 cell proliferation and cell migration assay rather the domain of VEGFR is conserved to be targeted by luteolin, lupeol and lectin.

  5. The down-stream effects of mannan-induced lectin complement pathway activation depend quantitatively on alternative pathway amplification

    DEFF Research Database (Denmark)

    Harboe, Morten; Garred, Peter; Karlstrøm, Ellen

    2009-01-01

    Complement activation plays an important role in human pathophysiology. The effect of classical pathway activation is largely dependent on alternative pathway (AP) amplification, whereas the role of AP for the down-stream effect of mannan-induced lectin pathway (LP) activation is poorly understood...... that AP amplification is quantitatively responsible for the final effect of initial specific LP activation. TCC generation on the solid phase was distinctly but less inhibited by anti-fD. C2 bypass of the LP pathway could be demonstrated, and AP amplification was also essential during C2 bypass in LP...... as shown by complete inhibition of TCC generation in C2-deficient serum by anti-fD and anti-properdin antibodies. In conclusion, the down-stream effect of LP activation depends strongly on AP amplification in normal human serum and in the C2 bypass pathway....

  6. Activity and Safety of Synthetic Lectins Based on Benzoboroxole-Functionalized Polymers for Inhibition of HIV Entry

    Science.gov (United States)

    Mahalingam, Alamelu; Geonnotti, Anthony R.; Balzarini, Jan; Kiser, Patrick F.

    2011-01-01

    Lectins derived from plant and microbial sources constitute a vital class of entry inhibitors that target the oligomannose residues on the HIV envelope gp120. Despite their potency and specificity, success of lectin-based entry inhibitors may be impeded by issues in regards to economical production, formulation and potential mitogenicity. Therefore, there exists a gap in the HIV therapeutics pipeline that underscores the need for mass producible, synthetic, broad-spectrum, and biocomptabile inhibitors of HIV entry. Here, we present the development of a polymeric synthetic lectin, based on benzoboroxole (BzB), which exhibits weak affinity (~25 M−1) for non-reducing sugars, similar to those found on the HIV envelope. High molecular weight BzB-functionalized polymers demonstrated antiviral activity that increased with an increase in ligand density and molecular weight of the polymer construct; revealing that polyvalency improves activity. Polymers showed significant increase in activity from 25 to 75 mol% BzB functionalization with EC50 of 15 μM and 15 nM, respectively. A further increase in mole functionalization to 90% resulted in an increase of the EC50 (59 ± 5 nM), likely due to the elongated rigid structure of the polymer chain compelled by electrostatic repulsion between the boronic acid groups. An increase in molecular weight of the polymer at 50 mol% BzB functionalization showed a gradual but significant increase in antiviral activity, with the highest activity seen with the 382 kDa polymer (EC50 of 1.1 ± 0.5 nM in CEM cells and 11 ± 3 nM in TZM-bl cells). Supplementing the polymer backbone with 10 mol% sulfonic acid not only increased the aqueous solubility of the polymers by at least 50-fold, but also demonstrated a synergistic increase in anti-HIV activity (4.0 ± 1.5 nM in TZM-bl cells), possibly due to electrostatic interactions between the negatively charged polymer backbone and the positively charged V3-loop in the gp120. The benzoboroxole

  7. Detection of Cytotoxic Activity of Lectin on Human Colon Adenocarcinoma (Sw480 and Epithelial Cervical Carcinoma (C33-A

    Directory of Open Access Journals (Sweden)

    Mirandeli Bautista

    2011-03-01

    Full Text Available Lectins comprise a heterogeneous class of proteins that recognize the carbohydrate moieties of glycoconjugates with high specificity. Numerous studies have shown that lectins are capable of recognizing specific carbohydrate moieties displayed by malignant cells or tissues. The present work was performed to investigate the effects of tepary bean (Phaseolus acutifolius lectins on proliferation, colony formation, and alteration of DNA synthesis of human malignant cells. Tepary bean lectin showed dose dependent  effects on the inhibition of viability as well as on colony formation in two human malignant cells lines (C33-A, Sw480; By contrast, tepary bean lectin only showed significant effects on DNA synthesis on Sw480 cells. Our results provide evidence of the anti- proliferative and cytotoxic effects of the tepary bean lectins on C33-A and Sw480 cells lines.

  8. Lectins in human pathogenic fungi.

    Science.gov (United States)

    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). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  9. PO-20 - Crosstalk between the lectin pathway and haemostasis in patients with pulmonary cancer

    DEFF Research Database (Denmark)

    Larsen, J B; Christensen, T D; Hvas, C L

    2016-01-01

    INTRODUCTION: Recent research has focused on the complement system in cancer, including the lectin pathway of complement activation. Mannose-binding lectin (MBL), a key activator of the lectin pathway, can bind to tumor cell surfaces in vitro, and lectin pathway activation is increased in several...

  10. Electroluminescent TCC, C3dg and fB/Bb epitope assays for profiling complement cascade activation in vitro using an activated complement serum calibration standard.

    Science.gov (United States)

    van Vuuren, B Jansen; Bergseth, G; Mollnes, T E; Shaw, A M

    2014-01-15

    Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Complement activating soluble pattern recognition molecules with collagen-like regions, mannan-binding lectin, ficolins and associated proteins

    DEFF Research Database (Denmark)

    Thiel, Steffen

    2007-01-01

    Mannan-binding lectin (MBL), L-ficolin, M-ficolin and H-ficolin are all complement activating soluble pattern recognition molecules with recognition domains linked to collagen-like regions. All four may form complexes with four structurally related proteins, the three MBL-associated serine...... proteases (MASPs), MASP-1, MASP-2 and MASP-3, and a smaller MBL-associated protein (MAp19). The four recognition molecules recognize patterns of carbohydrate or acetyl-group containing ligands. After binding to the relevant targets all four are able to activate the complement system. We thus have a system...... where four different and/or overlapping patterns of microbial origin or patterns of altered-self may be recognized, but in all cases the signalling molecules, the MASPs, are shared. MASP-1 and MASP-3 are formed from one gene, MASP1/3, by alternative splicing generating two different mRNAs from a single...

  12. Synthesis of porous carbon-doped g-C_3N_4 nanosheets with enhanced visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Bao, Nan; Hu, Xinde; Zhang, Qingzhe; Miao, Xinhan; Jie, Xiuyan; Zhou, Shuai

    2017-01-01

    Highlights: • NSs-APAM photocatalysts were synthesized by a green and handy route. • APAM was used as the intercalator and carbon source in the preparation. • The combination of photo-induced charge carriers was greatly restrained. • Significantly enhanced visible-light photocatalytic activity was witnessed. • The NSs-APAM also showed a good recycling stability. - Abstract: The porous carbon-doped g-C_3N_4 nanosheets photocatalysts (NSs-APAM) were synthesized using anionic polyacrylamide (APAM) as the intercalator and carbon source via the thermal treatment method. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance absorption spectra (UV-DRS) and photoluminescence spectroscopy (PL). The results indicate that the APAM can effectively induce the formation of high-quality nanosheets (NSs) with narrowed bandgap. The specific surface area of NSs-APAM is 118.6 m"2/g, which is 5-fold larger than bulk g-C_3N_4. The carbon doping could narrow the bandgap, from 2.75 eV of g-C_3N_4 NSs without carbon doping (NSs-Water) to 2.41 eV of NSs-APAM. The two-dimensional NSs structure facilitates the charge separation by shortening the diffusion distance to the surface of photocatalysts. The synergic effects of the carbon doping and unique structural properties contributed to the superior photocatalytic activity of NSs-APAM with 95% degradation rate towards X–3 B after 30 min visible-light irradiation.

  13. Venom of the Peruvian snake Bothriopsis oligolepis: Detection of antibacterial activity and involvement of proteolytic enzymes and C-type lectins in growth inhibition of Staphylococcus aureus.

    Science.gov (United States)

    Sulca, M A; Remuzgo, C; Cárdenas, J; Kiyota, S; Cheng, E; Bemquerer, M P; Machini, M T

    2017-08-01

    There is a rising interest in snake venoms proteins (SVPs) because these macromolecules are related to pharmacological properties that manifest themselves during poisoning and can lead to secondary microbial infections. Interestingly, researchers have somehow neglected the antimicrobial activity of SVPs. The aims of this study were: (i) to verify whether the venom of the Peruvian snake Bothriopsis oligolepis displays such activity; (ii) to isolate and identify some of its antimicrobial constituents. Liquid growth inhibition assays revealed that the crude venom inhibited the growth of Gram-positive and Gram-negative bacteria, but not of Candida species. Fractionation of the venom by anion-exchange chromatography provided fractions P2, P4 and P8 active against S. aureus. Fractionation of P2 or P8 by gel-filtration chromatography and of P4 by RP-HPLC furnished the sub-fractions P2-I, P8-II and P4-II, respectively, being those fractions active against S. aureus. Analyses of these sub-fractions by SDS-PAGE under denaturing/reducing conditions evidenced SVPs with 59-73, 27 and 14-28 kDa, respectively. Their in-gel tryptic digestion gave peptide fragments, whose sequencing by MALDI-TOF/MS followed by protein BLAST analysis allowed identifying PIII metalloprotease(s) [SVMP(s)] in P2-I, serine protease(s) [SVSP(s)] in P4-II and lectin(s) in P8-II. Detection of gelatinolytic activity in P2-I and P4-II reinforced the existence of PIII-SVMP(s) and SVSP(s), respectively. Activation of the coagulation cascade intrinsic pathway by P8-II (probably by interaction with factors IX and/or X as some snake C-type lectins do) supported the presence of C-type lectin(s). Altogether, these new findings reveal that the venom of the Peruvian snake Bothriopsis oligolepis displays antibacterial activity and that the isolated SVMP(s), SVSP(s) and C-type lectin(s) are associated to its ability to inhibit the growth of S. aureus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, Jens Christian; Christensen, I J

    2004-01-01

    in certain patient groups. It is hypothesized that a deficient MBL pathway might be more frequent among patients with CRC than in healthy individuals. The MBL pathway was therefore evaluated in serum obtained preoperatively from 193 patients with primary CRC and in serum from 150 healthy volunteers. METHODS......: Serum MBL concentrations and MBL/MASP activity were determined using immunofluorometric assays. The levels are presented as the median, inter-quartile range and range. RESULTS: Serum MBL levels were significantly (P ..., inter-quartile range) compared with levels in healthy blood donors (924 (230-1476) ng/mL). Similarly, the MBL/MASP activity was significantly (P age, gender, tumour location...

  15. Cooperation between MASP-1 and MASP-2 in the generation of C3 convertase through the MBL pathway

    DEFF Research Database (Denmark)

    Møller-Kristensen, Mette; Thiel, Steffen; Sjöholm, Anders

    2007-01-01

    The complement system is an important part of the innate immune system. Three pathways, the classical, the alternative and the lectin pathway, lead to the cleavage of complement factor C3, a central event in the activation of the complement system. We investigated the deposition of C3b (solid-pha....... Our results demonstrate a function of the orphan protease MASP-1 by providing evidence that this enzyme collaborates with MASP-2 in the generation of C3 convertase, a process observable at high serum concentration, but not at low serum concentration...

  16. Human complement component C3

    DEFF Research Database (Denmark)

    Behrendt, N

    1985-01-01

    The two common genetic variants of human C3, C3 S and C3 F, were purified and characterized by SDS-PAGE, agarose gel electrophoresis, isoelectric focusing and amino acid analysis. The difference in electrophoretic mobility between the two variants was conserved after purification, and by isoelect......The two common genetic variants of human C3, C3 S and C3 F, were purified and characterized by SDS-PAGE, agarose gel electrophoresis, isoelectric focusing and amino acid analysis. The difference in electrophoretic mobility between the two variants was conserved after purification......, and by isoelectric focusing of the hemolytically active proteins, pI values of 5.86 and 5.81 were determined for C3 S and C3 F, respectively. Any difference in amino acid composition was too small to be detected by amino acid analysis, and the two proteins had the same molecular weight as determined by SDS-PAGE....

  17. The application of the determination of activity of red blood cell C3B receptor in observation of radiation effects

    International Nuclear Information System (INIS)

    Cui Shuling

    1985-01-01

    The activity of red blood cell C 3 B receptor has been determined in the cases of 101 healthy persons, 42 chest fluoroscopies (healthy blood donors) and 30 G.I. examination (non-cancer patients) before and after exposure, respectively. The results showed that the rate of immune adherence is 17.2 +- 2.8% in normal control group, 16.2 +- 2.4% and 12.4 +- 1.2% in chest fluoroscopies group (mean exposure doses of surface of body 1.59 R) and 16.4 +- 2.6% and 13.3 +- 1.7% in G.I. examination group (mean exposure doses of surface of body 7.28 R) before and after exposure respectively. All of the exposure groups showed significant changes (P < 0.001) compared with the normal control group and that before examination

  18. Differential in vitro inhibitory activity against HIV-1 of alpha-(1-3- and alpha-(1-6-D-mannose specific plant lectins : Implication for microbicide development

    Directory of Open Access Journals (Sweden)

    Balzarini Jan

    2007-06-01

    Full Text Available Abstract Background Plant lectins such as Galanthus nivalis agglutinin (GNA and Hippeastrum hybrid agglutinin (HHA are natural proteins able to link mannose residues, and therefore inhibit HIV-target cell interactions. Plant lectins are candidate for microbicide development. Objective To evaluate the activity against HIV of the mannose-specific plant lectins HHA and GNA at the cellular membrane level of epithelial cells and monocyte-derived dendritic cells (MDDC, two potential target cells of HIV at the genital mucosal level. Methods The inhibitory effects of HHA and GNA were evaluated on HIV adsorption to genital epithelial HEC-1A cell line, on HIV transcytosis throughout a monolayer of polarized epithelial HEC-1A cells, on HIV adsorption to MDDC and on transfer of HIV from MDDC to autologous T lymphocytes. Results HHA faintly inhibited attachment to HEC-1A cells of the R5-tropic HIV-1Ba-L strain, in a dose-dependent manner, whereas GNA moderately inhibited HIV adsorption in the same context, but only at high drug doses. Only HHA, but not GNA, inhibited HIV-1JR-CSF transcytosis in a dose-dependent manner. By confocal microscopy, HHA, but not GNA, was adsorbed at the epithelial cell surface, suggesting that HHA interacts specifically with receptors mediating HIV-1 transcytosis. Both plant lectins partially inhibited HIV attachment to MDDC. HHA inhibited more efficiently the transfer of HIV from MDDC to T cell, than GNA. Both HHA and GNA lacked toxicity below 200 μg/ml irrespective the cellular system used and do not disturb the monolayer integrity of epithelial cells. Conclusion These observations demonstrate higher inhibitory activities of the lectin plant HHA by comparison to GNA, on HIV adsorption to HEC-1A cell line, HIV transcytosis through HEC-1A cell line monolayer, HIV adsorption to MDDC and HIV transfer from MDDC to T cells, highlighting the potential interest of HHA as effective microbicide against HIV.

  19. Fabrication of Z-scheme plasmonic photocatalyst Ag@AgBr/g-C3N4 with enhanced visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Yang, Yuxin; Guo, Wan; Guo, Yingna; Zhao, Yahui; Yuan, Xing; Guo, Yihang

    2014-01-01

    Graphical abstract: - Highlights: • Z-scheme plasmonic photocatalyst of Ag@AgBr/g-C 3 N 4 is prepared for the first time. • Ag@AgBr/g-C 3 N 4 shows enhanced visible-light photocatalytic activity. • Photocatalytic mechanism based on the experimental results is revealed. • Photocatalytic degradation pathway of MO is put forward. - Abstract: A series of Ag@AgBr grafted graphitic carbon nitride (Ag@AgBr/g-C 3 N 4 ) plasmonic photocatalysts are fabricated through photoreducing AgBr/g-C 3 N 4 hybrids prepared by deposition–precipitation method. The phase and chemical structures, electronic and optical properties as well as morphologies of Ag@AgBr/g-C 3 N 4 heterostructures are well-characterized. Subsequently, the photocatalytic activity of Ag@AgBr/g-C 3 N 4 is evaluated by the degradation of methyl orange (MO) and rhodamin B (RB) under visible-light irradiation. The enhanced photocatalytic activity of Ag@AgBr/g-C 3 N 4 compared with g-C 3 N 4 and Ag@AgBr is obtained and explained in terms of the efficient visible-light utilization efficiency as well as the construction of Z-scheme, which keeps photogenerated electrons and holes with high reduction and oxidation capability, evidenced by photoelectrochemical tests and free radical and hole scavenging experiments. Based on the intermediates identified in the reaction system, the photocatalytic degradation pathway of MO is put forward

  20. Unique bar-like sulfur-doped C3N4/TiO2 nanocomposite: Excellent visible light driven photocatalytic activity and mechanism study

    Science.gov (United States)

    Zhao, Yu; Xu, Shiping; Sun, Xiang; Xu, Xing; Gao, Baoyu

    2018-04-01

    In this work, a nanocomposite of TiO2 nanoparticles coupled with sulfur-doped C3N4 (S-C3N4) laminated layer was successfully fabricated using a facile impregnation method and the nanocomposite exhibited superior photocatalytic activity in pollutant removal under visible light irradiation, compared to bare TiO2, g-C3N4 and binary C3N4-TiO2 nanocomposite. The enhanced photocatalytic activity was benefited from the efficient migration and transformation of electron-hole (e--h+) pairs, improved visible light absorption capability, and relatively large specific surface area induce by sulfur doping. Interestingly, the introduction of sulfur changes regulated the morphology of g-C3N4 leading to the formation of ultrathin g-C3N4 layer nanosheet assemblies and unique bar-like g-C3N4/TiO2 nanocomposite, which is beneficial for the outstanding performance of the product. In addition, trapping experiment was carried out to identify the main active species in the photocatalytic reaction over the S-C3N4/TiO2 photocatalyst, and functional mechanism of the composite was proposed. This work may provide new ideas for the fabrication and utilization of highly efficient photocatalyst with excellent visible light response in environmental purification applications.

  1. Identification of a C-type lectin with antiviral and antibacterial activity from pacific white shrimp Litopenaeus vannamei.

    Science.gov (United States)

    Li, Ming; Li, Chaozheng; Ma, Chunxia; Li, Haoyang; Zuo, Hongliang; Weng, Shaoping; Chen, Xiaohan; Zeng, Digang; He, Jianguo; Xu, Xiaopeng

    2014-10-01

    C-type lectins (CTLs) play crucial roles in innate immune responses in invertebrates by recognizing and eliminating microinvaders. In this study, a CTL from pacific white shrimp Litopenaeus vannamei (LvCTL3) was identified. LvCTL3 contains a single C-type lectin-like domain (CTLD), which shows similarities to those of other shrimp CTLs and has a mutated 'EPD' motif in Ca(2+)-binding site 2. LvCTL3 mRNA can be detected in all tested tissues and expression of LvCTL3 in gills was up-regulated after Lipopolysaccharides, poly (I:C), Vibrio parahaemolyticus and white spot syndrome virus (WSSV) challenges, suggesting activation responses of LvCTL3 to bacterial, virus and immune stimulant challenges. The 5'flanking regulatory region of LvCTL3 was cloned and we identified a NF-κB binding motif in the LvCTL3 promoter region. Dual-luciferase reporter assays indicated that over-expression of L. vannamei dorsal can dramatically up regulate the promoter activity of LvCTL3, suggesting that LvCTL3 expression could be regulated through NF-κB signaling pathway. As far as we know, this is the first report on signaling pathway involve in shrimp CTLs expression. The recombinant LvCTL3 protein was expressed in Escherichia coli and purified by Ni-affinity chromatography. The purified LvCTL3 can agglutinate Gram-negative microbe Vibrio alginolyticus and V. parahaemolyticus and Gram-positive bacteria Bacillus subtilis in the presence of calcium ions, but cannot agglutinate Gram-positive bacteria Streptococcus agalactiae. The agglutination activity of LvCTL3 was abolished when Ca(2+) was chelated with EDTA, suggesting the function of LvCTL3 is Ca(2+)-dependent. In vivo challenge experiments showed that the recombinant LvCTL3 protein can significantly reduce the mortalities of V. parahemolyticus and WSSV infection, indicating LvCTL3 might play significant roles in shrimp innate immunity defense against bacterial and viral infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Synthesis of MoS_2/g-C_3N_4 nanosheets as 2D heterojunction photocatalysts with enhanced visible light activity

    International Nuclear Information System (INIS)

    Li, Juan; Liu, Enzhou; Ma, Yongning; Hu, Xiaoyun; Wan, Jun; Sun, Lin; Fan, Jun

    2016-01-01

    Graphical abstract: TEM image and schematic diagram of photocatalytic mechanism of 2D MoS_2/g-C_3N_4 composites. - Highlights: • g-C_3N_4 nanosheets coupled with MoS_2 nanosheets as 2D heterojunction photocatalysts were synthesized successfully. • The 2D MoS_2/g-C_3N_4 heterojunctions show higher photocatalytic activity than pure g-C_3N_4. • The photocatalytic mechanism of the 2D MoS_2/g-C_3N_4 heterojunction was described. - Abstract: g-C_3N_4 nanosheets coupled with MoS_2 nanosheets as 2D heteroconjuction were prepared via a facile impregnation and calcination method. The structure characterization clearly indicated that MoS_2 nanosheets were successfully horizontal loaded on g-C_3N_4 nanosheets. The investigation indicated that the formation of 2D heterojunction between the g-C_3N_4 nanosheets and MoS_2 nanosheets promoted the charge transfer and enhanced separation efficiency of photoinduced electron–hole pairs. Furthermore, the measurement of photocatalytic activity for the degradation of rhodamine B and methyl orange revealed that the as-prepared 2D MoS_2/g-C_3N_4 heterojunction exhibited the significantly enhanced photocatalytic activity and considerable stability under visible light irradiation. The 2D MoS_2/g-C_3N_4 heterojunction prepared with 3 wt% of MoS_2 exhibited the optimal photodegradable efficiency. The present work shows that the formation of 2D heterojunction should be a good strategy to design efficient photocatalysts.

  3. A Cost-Effective Solid-State Approach to Synthesize g-C3N4 Coated TiO2 Nanocomposites with Enhanced Visible Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Min Fu

    2013-01-01

    Full Text Available Novel graphitic carbon nitride (g-C3N4 coated TiO2 nanocomposites were prepared by a facile and cost-effective solid-state method by thermal treatment of the mixture of urea and commercial TiO2. Because the C3N4 was dispersed and coated on the TiO2 nanoparticles, the as-prepared g-C3N4/TiO2 nanocomposites showed enhanced absorption and photocatalytic properties in visible light region. The as-prepared g-C3N4 coated TiO2 nanocomposites under 450°C exhibited efficient visible light photocatalytic activity for degradation of aqueous MB due to the increased visible light absorption and enhanced MB adsorption. The g-C3N4 coated TiO2 nanocomposites would have wide applications in both environmental remediation and solar energy conversion.

  4. Chemical-modification studies of a unique sialic acid-binding lectin from the snail Achatina fulica. Involvement of tryptophan and histidine residues in biological activity.

    Science.gov (United States)

    Basu, S; Mandal, C; Allen, A K

    1988-01-01

    A unique sialic acid-binding lectin, achatininH (ATNH) was purified in single step from the haemolymph of the snail Achatina fulica by affinity chromatography on sheep submaxillary-gland mucin coupled to Sepharose 4B. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. Amino acid analysis showed that the lectin has a fairly high content of acidic amino acid residues (22% of the total). About 1.3% of the residues are half-cystine. The glycoprotein contains 21% carbohydrate. The unusually high content of xylose (6%) and fucose (2.7%) in this snail lectin is quite interesting. The protein was subjected to various chemical modifications in order to detect the amino acid residues and carbohydrate residues present in its binding sites. Modification of tyrosine and arginine residues did not affect the binding activity of ATNH; however, modification of tryptophan and histidine residues led to a complete loss of its biological activity. A marked decrease in the fluorescence emission was found as the tryptophan residues of ATNH were modified. The c.d. data showed the presence of an identical type of conformation in the native and modified agglutinin. The modification of lysine and carboxy residues partially diminished the biological activity. The activity was completely lost after a beta-elimination reaction, indicating that the sugars are O-glycosidically linked to the glycoprotein's protein moiety. This result confirms that the carbohydrate moiety also plays an important role in the agglutination property of this lectin. Images Fig. 3. PMID:3140796

  5. Magnetically Separable Fe2O3/g-C3N4 Nanocomposites with Cocoon-Like Shape: Magnetic Properties and Photocatalytic Activities

    Science.gov (United States)

    Yu, Xiaojia; Yang, Xiaoyu; Li, Guang

    2018-01-01

    We report magnetically separable Fe2O3/g-C3N4 nanocomposites as a photocatalyst under visible-light irradiation in this study. The Fe2O3/g-C3N4 nanocomposites were synthesized through a two-step hydrothermal method. The Fe2O3 with cocoon-like shape was obviously dispersed on the surface of g-C3N4 with porous and layered nanostructure as seen from micrographs of the particles. Furthermore, the magnetic conversion of the samples was studied via vibrating sample magnetometer technology. It was found that the saturated magnetization Ms of the Fe2O3/g-C3N4 nanoparticles obviously decreased in the presence of g-C3N4, and the photocatalytic activity of the samples investigated by degrading Rhodamine B suggested that the Fe2O3/g-C3N4 photocatalyst was prior to the pure Fe2O3 and g-C3N4 samples. In addition, the magnetically separable ability of Fe2O3/g-C3N4 nanocomposites was efficiently exhibited by an external magnet.

  6. Glycoprotein profiles of macrophages at different stages of activation as revealed by lectin binding after electrophoretic separation.

    Science.gov (United States)

    Irimura, T; North, S M; Nicolson, G L

    1987-01-01

    Glycoprotein profiles of rat macrophages (M phi) at different stages of activation were studied by examining the reactivity of various lectins to the glycoproteins separated by polyacrylamide gel electrophoresis. Ricinus communis agglutinin 1 (RCA1) revealed several components including glycoproteins of Mr 160 kDa and 65 kDa prominent in resident M phi. A pokeweed mitogen (PWM) isolectin, Pa-4, recognizes branched poly(N-acetyllactosamine)-type carbohydrate chains, and revealed a significant increase in glycoproteins of Mr ranging from 70 kDa to 150 kDa on thioglycolate-elicited M phi. Increased reactivity of PWM to thioglycolate-elicited M phi was observed by direct binding of 125I-labeled Pa-4 to intact or glutaraldehyde-fixed M phi. Histochemical staining of formaldehyde-fixed M phi in vitro with biotinylated Pa-4 was consistent with the gel analysis, that is, resident M phi had no reactivity while thioglycolate-elicited M phi showed slight reactivity. Alveolar and intratumoral M phi bound more Pa-4 than resident or thioglycolate-elicited M phi. The PWM isolectin may therefore serve as a marker for an early stage of M phi activation.

  7. Quantitative analysis of receptor-mediated uptake and pro-apoptotic activity of mistletoe lectin-1 by high content imaging.

    Science.gov (United States)

    Beztsinna, N; de Matos, M B C; Walther, J; Heyder, C; Hildebrandt, E; Leneweit, G; Mastrobattista, E; Kok, R J

    2018-02-09

    Ribosome inactivating proteins (RIPs) are highly potent cytotoxins that have potential as anticancer therapeutics. Mistletoe lectin 1 (ML1) is a heterodimeric cytotoxic protein isolated from European Mistletoe and belongs to RIP class II. The aim of this project was to systematically study ML1 cell binding, endocytosis pathway(s), subcellular processing and apoptosis activation. For this purpose, state of the art cell imaging equipment and automated image analysis algorithms were used. ML1 displayed very fast binding to sugar residues on the membrane and energy-dependent uptake in CT26 cells. The co-staining with specific antibodies and uptake blocking experiments revealed involvement of both clathrin-dependent and -independent pathways in ML1 endocytosis. Co-localization studies demonstrated the toxin transport from early endocytic vesicles to Golgi network; a retrograde road to the endoplasmic reticulum. The pro-apoptotic and antiproliferative activity of ML1 were shown in time lapse movies and subsequently quantified. ML1 cytotoxicity was less affected in multidrug resistant tumor cell line 4T1 in contrast to commonly used chemotherapeutic drug (ML1 resistance index 6.9 vs 13.4 for doxorubicin; IC 50 : ML1 1.4 ng/ml vs doxorubicin 24000 ng/ml). This opens new opportunities for the use of ML1 as an alternative treatment in multidrug resistant cancers.

  8. The Emerging Role of Complement Lectin Pathway in Trypanosomatids: Molecular Bases in Activation, Genetic Deficiencies, Susceptibility to Infection, and Complement System-Based Therapeutics

    Directory of Open Access Journals (Sweden)

    Ingrid Evans-Osses

    2013-01-01

    Full Text Available The innate immune system is evolutionary and ancient and is the pivotal line of the host defense system to protect against invading pathogens and abnormal self-derived components. Cellular and molecular components are involved in recognition and effector mechanisms for a successful innate immune response. The complement lectin pathway (CLP was discovered in 1990. These new components at the complement world are very efficient. Mannan-binding lectin (MBL and ficolin not only recognize many molecular patterns of pathogens rapidly to activate complement but also display several strategies to evade innate immunity. Many studies have shown a relation between the deficit of complement factors and susceptibility to infection. The recently discovered CLP was shown to be important in host defense against protozoan microbes. Although the recognition of pathogen-associated molecular patterns by MBL and Ficolins reveal efficient complement activations, an increase in deficiency of complement factors and diversity of parasite strategies of immune evasion demonstrate the unsuccessful effort to control the infection. In the present paper, we will discuss basic aspects of complement activation, the structure of the lectin pathway components, genetic deficiency of complement factors, and new therapeutic opportunities to target the complement system to control infection.

  9. Relations between Structure, Activity and Stability in C3N4 Based Photocatalysts Used for Solar Hydrogen Production

    Directory of Open Access Journals (Sweden)

    Ramesh P. Sivasankaran

    2018-01-01

    Full Text Available Solar hydrogen production from water could be a sustainable and environmentally friendly alternative to fossil energy carriers, yet so far photocatalysts active and stable enough for large-scale applications are not available, calling for advanced research efforts. In this work, H2 evolution rates of up to 1968 and 5188 μmol h−1 g−1 were obtained from aqueous solutions of triethanolamine (TEOA and oxalic acid (OA, respectively, by irradiating composites of AgIn5S8 (AIS, mesoporous C3N4 (CN, surface area >150 m2/g and ≤2 wt.% in-situ photodeposited Pt nanoparticles (NPs with UV-vis (≥300 nm and pure visible light (≥420 nm. Structural properties and electron transport in these materials were analyzed by XRD, STEM-HAADF, XPS, UV-vis-DRS, ATR-IR, photoluminescence and in situ-EPR spectroscopy. Initial H2 formation rates were highest for Pt/CN, yet with TEOA this catalyst deactivated by inclusion of Pt NPs in the matrix of CN (most pronounced at λ ≥ 300 nm while it remained active with OA, since in this case Pt NPs were enriched on the outermost surface of CN. In Pt/AIS-CN catalysts, Pt NPs were preferentially deposited on the surface of the AIS phase which prevents them from inclusion in the CN phase but reduces simultaneously the initial H2 evolution rate. This suggests that AIS hinders transport of separated electrons from the CN conduction band to Pt NPs but retains the latter accessible by protons to produce H2.

  10. Facile synthesis of highly reactive and stable Fe-doped g-C3N4 composites for peroxymonosulfate activation: A novel nonradical oxidation process.

    Science.gov (United States)

    Feng, Yong; Liao, Changzhong; Kong, Lingjun; Wu, Deli; Liu, Yiming; Lee, Po-Heng; Shih, Kaimin

    2018-07-15

    Ferrous ions (Fe 2+ ) are environmentally friendly materials but show extremely inefficient persulfate activation. Polymeric graphitic carbon nitride (g-C 3 N 4 ) has recently shown potential to activate persulfates, but the process requires intense light irradiation. To overcome these drawbacks, we designed an innovative heterogeneous iron catalyst by doping Fe into g-C 3 N 4 (Fe-g-C 3 N 4 ) and used it to activate peroxymonosulfate (PMS) for degradation of pollutant phenol. The catalysts synthesized were fully characterized with various techniques, such as X-ray diffraction, Mössbauer spectroscopy, and X-ray photoelectron spectroscopy. Fe was found to be coordinated with the framework of g-C 3 N 4 . Approximately 100% degradation of phenol was achieved with Fe-g-C 3 N 4 after 20 min of reaction, whereas less than 5% degradation of phenol was achieved with Fe 2+ . Fe-g-C 3 N 4 -PMS had a wide effective pH range, and its reactivity was nearly independent of natural illumination. In contrast to the previously proposed radical mechanisms, quenching experiments revealed that nonradical oxidation contributed to the observed degradation. The OO bond in the activated PMS likely underwent heterolysis, producing high-valence iron species (Fe IV O) as the primary active species. These findings have important implications for the development of a selective heterogeneous nonradical-oxidation process. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Mushroom Lectins: Specificity, Structure and Bioactivity Relevant to Human Disease

    Directory of Open Access Journals (Sweden)

    Mohamed Ali Abol Hassan

    2015-04-01

    Full Text Available 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.

  12. Activation and binding of opsonic fragments of C3 on encapsulated Cryptococcus neoformans by using an alternative complement pathway reconstituted from six isolated proteins.

    Science.gov (United States)

    Kozel, T R; Wilson, M A; Pfrommer, G S; Schlageter, A M

    1989-07-01

    Encapsulated Cryptococcus neoformans yeast cells are potent activators of the complement system. We examined the interaction of the yeast cells with an alternative complement pathway reconstituted from isolated factor D, factor B, factor H, factor I, C3, and properdin. Incubation of encapsulated cryptococci with the reconstituted pathway led to activation and binding of C3 fragments to the yeast cells that was quantitatively and qualitatively identical to that observed with normal human serum. Incubation with either normal serum or a mixture of isolated proteins led to binding of 4 x 10(7) to 5 x 10(7) C3 molecules to the yeast cells. The kinetics for activation and binding of C3 were identical, with maximum binding observed after a 20-min incubation. Immunoglobulin G was not needed for optimal activation kinetics. C3 fragments eluted from the yeast cells by treatment with hydroxylamine and subsequent analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated the presence primarily of iC3b on yeast cells incubated with either normal serum or the reconstituted pathway. Ultrastructural examination of the opsonized yeast cells showed that the cryptococcal capsule was the site for binding of C3 activated from normal serum or the reconstituted pathway, with a dense accumulation of C3 at the periphery of the capsule. Thus, incubation of encapsulated cryptococci in the reconstituted pathway led to deposition of opsonic complement fragments at a site that was appropriate for interaction with phagocyte receptors. Cryptococci opsonized with the reconstituted pathway showed a markedly enhanced interaction with cultured human monocytes compared with unopsonized yeast cells, indicating that the alternative pathway alone is opsonic for yeast cells. However, the results indicate that additional serum factors are needed for optimal opsonization of yeast cells because a 35% reduction in the number of cryptococci bound to macrophages was observed with

  13. ABH antigens as recognition sites for the activation of red blood cell anion exchange by the lectin ulex europaeus agglutinin I.

    Science.gov (United States)

    Engelmann, B

    1993-11-01

    The blood group antigen H (blood group O) and fucose-specific lectin Ulex europaeus agglutinin I (UEA1) (10 micrograms/ml) was found to increase the rate constant of Cl- efflux into 100 mM Na+ oxalate media by about 40% in erythrocytes taken from antigen H donors. In 100 mM K+ oxalate, 150 mM Na+ pyruvate and in 150 mM Na+ acetate media the lectin elevated the rate constant of Cl- efflux by 20-50%. The acceleration of Cl- efflux by UEA1 was completely blocked by 10 microM 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS) indicating that the effect of the lectin is mediated by the anion exchanger of human erythrocytes (band 3 protein). In antigen A1 erythrocytes no significant stimulation of anion exchange by UEA1 was seen. The activation of Cl- efflux was completely prevented by addition of 1 mM fucose to the medium. These results suggest that the effect of UEA1 is mediated through interaction with the fucose residues of H antigens. Increasing extracellular Ca++ from 0.5 to 5 mM in Na+ pyruvate or Na+ acetate media slightly reduced the acceleration of anion exchange by the lectin. On the other hand, replacing part of extracellular chloride by bicarbonate did not considerably alter the (previously reported) stimulatory effect of UEA1 on red blood cell Ca++ uptake. This suggests that the acceleration of anion exchange and of Ca++ uptake by UEA1, respectively, are mediated by different mechanisms. It is concluded that UEA1 activates anion exchange of human erythrocytes most probably by a direct interaction with H antigens present on extracellular domains of the band 3 protein.

  14. Expression, purification, and refolding of active recombinant human E-selectin lectin and EGF domains in Escherichia coli.

    Science.gov (United States)

    Kawano, Susumu; Iyaguchi, Daisuke; Okada, Chiaki; Sasaki, Yusuke; Toyota, Eiko

    2013-06-01

    Attempts to obtain active E-selectin from Escherichia coli (E. coli) have not yet been successful. In this study, we succeeded in expressing the recombinant lectin and epidermal growth factor domain fragments of human E-selectin (rh-ESLE) in E. coli on a large-scale. The rh-ESLE protein was expressed as an inactive form in the inclusion bodies. The inactive form of rh-ESLE was denatured and solubilized by 6 M guanidine hydrochloride and then purified by Ni(2+) affinity chromatography under denaturing conditions. Denatured rh-ESLE was then refolded by a rapid-dilution method using a large amount of refolding buffer, which contained arginine and cysteine/cystine. The refolded rh-ESLE showed binding affinity for sLe(X) (K(d) = 321 nM, B(max) = 1.9 pmol/μg protein). This result suggests that the refolded rh-ESLE recovered its native and functional structure.

  15. Novel Z-scheme BiOBr/reduced graphene oxide/protonated g-C3N4 photocatalyst: Synthesis, characterization, visible light photocatalytic activity and mechanism

    Science.gov (United States)

    Bao, Yongchao; Chen, Kezheng

    2018-04-01

    The novel BiOBr/reduced graphene oxide/protonated g-C3N4 (BiOBr/RGO/pg-C3N4) composites were successfully synthesized by using a facile solvothermal synthesis method. The structure, morphology, optical and electronic properties were explored by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and photoelectrochemical measurement. The photocatalytic activities of as-synthesized samples were evaluated by the degradation of Rhodamine B (Rh B) and tetracycline hydrochloride (TC) aqueous solution under visible light irradiation (λ > 420nm). Compared with BiOBr, protonated g-C3N4 (pg-C3N4), BiOBr/pg-C3N4 and RGO/pg-C3N4, BiOBr/RGO/pg-C3N4 composites exhibited higher photocatalytic activity. The total organic carbon (TOC) removal ratios of Rh B and TC over 10% BiOBr/RGO/pg-C3N4 were 88% and 59%, respectively. The excellent photcatalytic performance was investigated by photoluminescence spectroscopy (PL), the radical quenching and electron spin resonance experiments. A Z-scheme charge transfer mechanism was proposed, in which RGO acted as an electron transfer mediator. It was worth pointing out that the closely contacted two-dimensional interface among the BiOBr, the RGO and pg-C3N4 promoted the separation and transfer of photo-generated charge carriers, and thus enhanced the photocatalytic efficiency.

  16. Construction of g-C_3N_4/Al_2O_3 hybrids via in-situ acidification and exfoliation with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Wang, Xiao-jing; Liu, Chao; Li, Xu-li; Li, Fa-tang; Li, Yu-pei; Zhao, Jun; Liu, Rui-hong

    2017-01-01

    Highlights: • Ultrathin g-C_3N_4/Al_2O_3 hybrids are prepared via in-situ reaction. • The structure modification role of in-situ formed HNO_3 for g-C_3N_4 is found. • The ultrathin g-C_3N_4 nanosheets are formed by the acidified melamine and Al(OH)_3. • In-situ calcination of melamine and Al(OH)_3 benefits the contact of C_3N_4 and Al_2O_3. • The activity of g-C_3N_4/Al_2O_3 is 16.6 times that of pristine g-C_3N_4 in degrading RhB. - Abstract: Homogeneous ultrathin g-C_3N_4 nanosheets/Al_2O_3 heterojunctions are synthesized using melamine and Al(NO_3)_3 via in-situ reaction and the following thermal polymerization approach. The in-situ reaction between melamine and Al(NO_3)_3 results in the existence of HNO_3-acidified melamine and Al(OH)_3 aggregates via the hydrolysis of Al(NO_3)_3. After thermal polymerization, the aggregates are converted to g-C_3N_4/Al_2O_3 composites. The thermal polymerization of acidified melamine and the support effect of aluminum hydroxide for g-C_3N_4 during the calcination process lead to highly dispersed amrophous Al_2O_3 on ultrathin g-C_3N_4 nanosheets, which is beneficial for the separation of photogenerated electron-hole pairs in the heterojunction. The degradation rate for Rhodamine B (RhB) over the most activie sample is 16.6 times than that of pristine g-C_3N_4 under visible light irradiation, which can be attributed to the high specific surface area, highly dispersion of amorphous Al_2O_3 on ultrathin g-C_3N_4 nanosheet, and the effective electrons transfer from g-C_3N_4 to the amorphous Al_2O_3.

  17. Antimicrobial and Antioxidant Activities and Effect of 1-Hexadecene Addition on Palmarumycin C2 and C3 Yields in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12

    Directory of Open Access Journals (Sweden)

    Yan Mou

    2013-12-01

    Full Text Available Two spirobisnaphthalenes, namely palmarumycins C2 and C3, were isolated from cultures of the endophytic fungus Berkleasmium sp. Dzf12 after treatment with 1-hexadecene. After addition of 1-hexadecene at 10% to the medium on day 6 of culture, the maximal yields of palmarumycins C2 and C3 were obtained as 0.40 g/L and 1.19 g/L, which were 40.00 fold and 59.50 fold higher, respectively, in comparison with those of the control (0.01 g/L and 0.02 g/L. The results indicated that addition of 1-hexadecene can be an effective strategy for enhancing the production of palmarumycins C2 and C3 in liquid culture of endophytic fungus Berkleasmium sp. Dzf12. Palmarumycin C3 exhibited stronger antimicrobial and antioxidant activities than palmarumycin C2.

  18. [Lectins, adhesins, and lectin-like substances of lactobacilli and bifidobacteria].

    Science.gov (United States)

    Lakhtin, V M; Aleshkin, V A; Lakhtin, M V; Afanas'ev, S S; Pospelova, V V; Shenderov, B A

    2006-01-01

    Cell-surface adhesion factors of lactobacilli and bifidobacteria, such as lectin/adhesin proteins of S-layers, secreted lectin-like bacteriocins, and lectin-like complexes, are considered and classified in the article. Certain general and specific properties of these factors are noted, such as in vitro and in vivo adhesion, cell co(aggregation), participation in the forming of microbial biofilms and colonization of mammalian alimentary tract, as well as complexation with biopolymers and bioeffectors, specificity to glycanes and natural glycoconjugates, domain and spatial organization of adhesion factors, co-functioning with other cytokines (pro- and anti-inflammatory ones), regulation of target cell properties, and other biological and physiological activities. The authors also note possibilities of application of lectins and lectin-like proteins of probiotic strains of lactobacilli and bifidobacteria in medicine and biotechnology.

  19. Surface modification of TiO2 with g-C3N4 for enhanced UV and visible photocatalytic activity

    International Nuclear Information System (INIS)

    Lei, Juying; Chen, Ying; Shen, Fan; Wang, Lingzhi; Liu, Yongdi; Zhang, Jinlong

    2015-01-01

    Highlights: • g-C 3 N 4 /TiO 2 was prepared by a one-step preparation under mild conditions. • Photocatalysts showed excellent activity under both UV and visible light. • A neat surface modification process is proved, excluding influence of N doping. • Two photocatalytic mechanisms under different wavelengths are proposed. • A wide range of available wavelengths would greatly improve practicability of TiO 2 . - Abstract: g-C 3 N 4 modified TiO 2 composites were prepared through a simple calcination process of anatase and cyanamide. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectrophotometry (DRS), fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry differential thermal analysis (TG–DTA) and X-ray photoelectron spectroscopy (XPS), proving a successful modification of TiO 2 with g-C 3 N 4 . Photodegradation of acid orange 7 (AO7) was used to evaluate the photocatalytic activities of the composites, showing excellent activity of them under both visible and UV light. In addition, base treatment was then introduced to investigate the interaction between g-C 3 N 4 and TiO 2 . After removing the g-C 3 N 4 modified on TiO 2 by base, no nitrogen doping is found in TiO 2 lattice, demonstrating the g-C 3 N 4 was surface attached on TiO 2 and attributing all improvement of photocatalytic activity of g-C 3 N 4 /TiO 2 composite to the synergy between the two semiconductors

  20. Compressible and Recyclable Monolithic g-C3N4/Melamine Sponge: A Facile Ultrasonic-coating Approach and Enhanced Visible-light Photocatalytic Activity

    Science.gov (United States)

    Yang, Ye; Zhang, Qian; Zhang, Ruiyang; Ran, Tao; Wan, Wenchao; Zhou, Ying

    2018-05-01

    Powdery photocatalysts seriously restrict their practical application due to the difficult recycle and low photocatalytic activity. In this work, a monolithic g-C3N4/melamine sponge (g-C3N4/MS) was successfully fabricated by a cost-effective ultrasonic-coating route, which is easy to achieve the uniform dispersion and firm loading of g-C3N4 on MS skeleton. The monolithic g-C3N4/MS entirely inherits the porous structure of MS and results in a larger specific surface area (SSA) than its powdery counterpart. Benefit from this monolithic structure, g-C3N4/MS gains more exposed active sites, enhanced visible-light absorption and separation of photogenerated carriers, thus achieving noticeable photocatalytic activity on nitric oxide (NO) removal, rhodamine B (RhB) degradation and CO2 reduction. Specifically, NO removal ratio is as high as 78.6% which is 4.5 times higher than that of the powdery g-C3N4, while RhB degradation rate reaches 97.88%, and yield rate of CO and CH4 attains 7.48 and 3.93 μmol g-1 h-1. Importantly, the features of low-density, high porosity, good elasticity and firmness, not only endow g-C3N4/MS with flexibility in various environmental applications, but also make it easy to recycle and stable for long-time application. Our work provides a feasible approach to fabricate novel monolithic photocatalysts with large-scale production and application.

  1. Metal organic framework g-C3N4/MIL-53(Fe) heterojunctions with enhanced photocatalytic activity for Cr(VI) reduction under visible light

    Science.gov (United States)

    Huang, Wenyuan; Liu, Ning; Zhang, Xiaodong; Wu, Minghong; Tang, Liang

    2017-12-01

    In this study, hybrid nanocomposites based on Fe-based MOF and graphitic carbon nitride (g-C3N4) were developed by a facile solvothermal method. The as-prepared materials were characterized by XRD, FESEM, TEM, XPS and PL analysis. It was showed that the introduction of a certain amount of g-C3N4 on the surface of MIL-53(Fe) would improve the separation and migration rate of photo-induced charges, consequently resulting in the boost of photocatalytic efficiency. Compared with g-C3N4 and MIL-53(Fe), the CMFe composites displayed more excellent visible light-resposive photocatalytic activity for the reduction of Cr(VI). The optimal doping content of g-C3N4 in g-C3N4/MIL-53(Fe) composite was determined to be 3.0 wt%, and it showed about 2.1 and 2.0 times as high photocatalytic efficiency for the reduction of Cr(VI) as that of pure g-C3N4 and MIL-53(Fe), respectively. Meanwhile, the composite exhibited good reusability and stability in the process of cyclic experiments. A possible photocatalytic reaction mechanism was also investigated in detail by the related electrochemical analysis.

  2. An acetylation site in lectin domain modulates the biological activity of polypeptide GalNAc-transferase-2

    DEFF Research Database (Denmark)

    Zlocowski, Natacha; Lorenz, Virginia; Bennett, Eric Paul

    2013-01-01

    Abstract Polypeptide GalNAc-transferases (ppGalNAc-Ts) are a family of enzymes that catalyze the initiation of mucin-type O-glycosylation. All ppGalNAc-T family members contain a common (QXW)3 motif which is present in R-type lectin group. Acetylation site K521 is part of the QKW motif of ß......-trefoil in the lectin domain of ppGalNAc-T2. We used a combination of acetylation and site-directed mutagenesis approaches to examine the functional role of K521 in ppGalNAc-T2. Binding assays of non-acetylated and acetylated forms of the mutant ppGalNAc-T2K521Q to various naked and aGalNAc-glycosylated mucin peptides...... indicated that degree of interaction of lectin domain with aGalNAc depends on the peptide sequence of mucin. Studies of inhibitory effect of various carbohydrates on interactions of ppGalNAc-T2 with MUC1aGalNAc indicate that point K521Q mutation enhance the carbohydrate specificity of lectin domain for aGalNAc...

  3. Lectin-Array Blotting.

    Science.gov (United States)

    Pazos, Raquel; Echevarria, Juan; Hernandez, Alvaro; Reichardt, Niels-Christian

    2017-09-01

    Aberrant protein glycosylation is a hallmark of cancer, infectious diseases, and autoimmune or neurodegenerative disorders. Unlocking the potential of glycans as disease markers will require rapid and unbiased glycoproteomics methods for glycan biomarker discovery. The present method is a facile and rapid protocol for qualitative analysis of protein glycosylation in complex biological mixtures. While traditional lectin arrays only provide an average signal for the glycans in the mixture, which is usually dominated by the most abundant proteins, our method provides individual lectin binding profiles for all proteins separated in the gel electrophoresis step. Proteins do not have to be excised from the gel for subsequent analysis via the lectin array but are transferred by contact diffusion from the gel to a glass slide presenting multiple copies of printed lectin arrays. Fluorescently marked glycoproteins are trapped by the printed lectins via specific carbohydrate-lectin interactions and after a washing step their binding profile with up to 20 lectin probes is analyzed with a fluorescent scanner. The method produces the equivalent of 20 lectin blots in a single experiment, giving detailed insight into the binding epitopes present in the fractionated proteins. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. An assay for the mannan-binding lectin pathway of complement activation

    DEFF Research Database (Denmark)

    Petersen, Steen Vang; Thiel, S; Jensen, L

    2001-01-01

    activation. Therefore, in a generally applicable complement activation assay specific for the MBL pathway, the activity of the classical pathway must be inhibited. This can be accomplished by exploiting the finding that high ionic strength buffers inhibit the binding of C1q to immune complexes and disrupt...

  5. T-antigen binding lectin with antibacterial activity from marine invertebrate, sea cucumber (Holothuria scabra): Possible involvement in differential recognition of bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Gowda, N.M.; Goswami, U.; Khan, M.I.

    report a study of a lectin (HSL) involved in immune response in the echinoderm, sea cucumber (Holothuria scabra). Correlative studies indicate that the expression of this defensive lectin is induced by bacterial challenge, wherein cell wall...

  6. Cyborg lectins: novel leguminous lectins with unique specificities.

    Science.gov (United States)

    Yamamoto, K; Maruyama, I N; Osawa, T

    2000-01-01

    Bauhinia purpurea lectin (BPA) is one of the beta-galactose-binding leguminous lectins. Leguminous lectins contain a long metal-binding loop, part of which determines their carbohydrate-binding specificities. Random mutations were introduced into a portion of the cDNA coding BPA that corresponds to the carbohydrate-binding loop of the lectin. An library of the mutant lectin expressed on the surface of lambda foo phages was screened by the panning method. Several phage clones with an affinity for mannose or N-acetylglucosamine were isolated. These results indicate the possibility of making artificial lectins (so-called "cyborg lectins") with distinct and desired carbohydrate-binding specificities.

  7. Lessons learned from mice deficient in lectin complement pathway molecules

    DEFF Research Database (Denmark)

    Genster, Ninette; Takahashi, Minoru; Sekine, Hideharu

    2014-01-01

    in turn activate downstream complement components, ultimately leading to elimination of the pathogen. Mice deficient in the key molecules of lectin pathway of complement have been generated in order to build knowledge of the molecular mechanisms of the lectin pathway in health and disease. Despite......The lectin pathway of the complement system is initiated when the pattern-recognition molecules, mannose-binding lectin (MBL), ficolins or collectin-11, bind to invading pathogens or damaged host cells. This leads to activation of MBL/ficolin/collectin-11 associated serine proteases (MASPs), which...... differences in the genetic arrangements of murine and human orthologues of lectin pathway molecules, the knockout mice have proven to be valuable models to explore the effect of deficiency states in humans. In addition, new insight and unexpected findings on the diverse roles of lectin pathway molecules...

  8. In vivo and in vitro antibacterial activity of conglutinin, a mammalian plasma lectin

    DEFF Research Database (Denmark)

    Friis-Christiansen, P; Thiel, S; Svehag, S E

    1990-01-01

    of BALB/c mice with Salmonella typhimurium is mediated by conglutinin. Conglutinin also demonstrated antibacterial activity against E. coli and S. typhimurium in vitro. The expression of this activity required the presence of heat-labile serum factors and peritoneal exudate or spleen cells...

  9. Room-temperature in situ fabrication of Bi2O3/g-C3N4 direct Z-scheme photocatalyst with enhanced photocatalytic activity

    Science.gov (United States)

    He, Rongan; Zhou, Jiaqian; Fu, Huiqing; Zhang, Shiying; Jiang, Chuanjia

    2018-02-01

    Constructing direct Z-scheme heterojunction is an effective approach to separating photogenerated charge carriers and improving the activity of semiconductor photocatalysts. Herein, a composite of bismuth(III) oxide (Bi2O3) and graphitic carbon nitride (g-C3N4) was in situ fabricated at room temperature by photoreductive deposition of Bi3+ and subsequent air-oxidation of the resultant metallic Bi. Quantum-sized ω-Bi2O3 nanoparticles approximately 6 nm in diameter were uniformly distributed on the surface of mesoporous g-C3N4. The as-prepared Bi2O3/g-C3N4 composite exhibited higher photocatalytic activity than pure Bi2O3 and g-C3N4 for photocatalytic degradation of phenol under visible light. Reactive species trapping experiments revealed that superoxide radicals and photogenerated holes played important roles in the photocatalytic degradation of phenol. The enhanced photocatalytic activity, identification of reactive species and higher rate of charge carrier recombination (as indicated by stronger photoluminescence intensity) collectively suggest that the charge migration within the Bi2O3/g-C3N4 composite followed a Z-scheme mechanism. Photogenerated electrons on the conduction band of Bi2O3 migrate to the valence band of g-C3N4 and combine with photogenerated holes therein. At the cost of these less reactive charge carriers, the Z-scheme heterojunction enables efficient charge separation, while preserving the photogenerated electrons and holes with stronger redox abilities, which is beneficial for enhanced photocatalytic activity.

  10. Rational construction of Z-scheme Ag_2CrO_4/g-C_3N_4 composites with enhanced visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Luo, Jin; Zhou, Xiaosong; Ma, Lin; Xu, Xuyao

    2016-01-01

    Highlights: • Novel visible-light driven Ag_2CrO_4/g-C_3N_4 composites were synthesized. • Ag_2CrO_4/g-C_3N_4 exhibited enhanced visible-light photocatalytic activity. • The reasons for the enhanced photocatalytic activity were revealed. - Abstract: Novel visible-light driven Z-scheme Ag_2CrO_4/g-C_3N_4 composites with different contents of Ag_2CrO_4 were fabricated by a facile chemical precipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy and photoelectrochemical measurements. Compared with individual g-C_3N_4 and Ag_2CrO_4, the Ag_2CrO_4/g-C_3N_4 composites displayed much larger photocatalytic activities for the photocatalytic degradation of methyl orange (MO) solution at room temperature under visible light irradiation (λ > 420 nm). Importantly, the optimum photodegradation rate constant of the Ag_2CrO_4/g-C_3N_4 composite at a theoretical weight content of 8.0% Ag_2CrO_4 for the photodegradation of MO was 0.0068 min"−"1, which was 5.7 and 4.3 times higher than that of pure g-C_3N_4 and Ag_2CrO_4, respectively. Such enormous enhancement in photocatalytic performance was predominantly ascribed to the efficient separation and transfer of photogenerated electrons and holes at the Ag_2CrO_4/g-C_3N_4 interface imparted through the Z-scheme electron transfer. Furthermore, radical trap experiments depicted that both the holes and superoxide radical anions were thought to dominate oxidative species of the Ag_2CrO_4/g-C_3N_4 composite for MO degradation under visible light irradiation. Ultimately, a tentative Z-scheme photodegradation mechanism was proposed. This work may be useful for the rational design of new types of Z-scheme photocatalysts and provide some illuminate insights into the Z-scheme transfer mechanism for application in energy

  11. Lectin, hemolysin and protease inhibitors in seed fractions with ovicidal activity against Haemonchus contortus.

    Science.gov (United States)

    Salles, Hévila Oliveira; Braga, Ana Carolina Linhares; Nascimento, Maria Thayana dos Santos Canuto do; Sousa, Ana Márjory Paiva; Lima, Adriano Rodrigues; Vieira, Luiz da Silva; Cavalcante, Antônio Cézar Rocha; Egito, Antonio Silvio do; Andrade, Lúcia Betânia da Silva

    2014-01-01

    Bioactive molecules of plant species are promising alternatives for the chemical control of gastrointestinal nematodes in ruminants. Extracts of native and exotic seed species from Brazil's semi-arid region were tested in vitro in an egg hatch assay and the bioactivity of their proteins was investigated. Each seed species was subjected to three extractions with three types of solvents. All the seeds showed ovicidal activity, which varied according to the solvents. Higher ovicidal activity was found in the molecule fractions of low molecular weight (Albizia lebbeck, Ipomoea asarifolia, Jatropha curcas, Libidibia ferrea, Moringa oleifera and Ricinus communis (P0.05, Bonferroni test). Hemagglutinating activity was detected in the fractions of C. spectabilis and M. oleifera fractions, hemolysin activity in the A. lebbeck and M. oleifera fractions, serine protease inhibitory activity in the A. lebbeck, I. asarifolia, J. curcas, M. oleifera and R. communis fractions, cysteine protease inhibitor activity in the M. oleifera fraction, and no protein activity in the L. ferrea fraction. The results of this work reveal new plant species with a potential for use in controlling nematode parasites in goats, thus opening a new field of research involving plant protein molecules with ovicidal properties.

  12. Lectin, hemolysin and protease inhibitors in seed fractions with ovicidal activity against Haemonchus contortus

    Directory of Open Access Journals (Sweden)

    Hévila Oliveira Salles

    Full Text Available Bioactive molecules of plant species are promising alternatives for the chemical control of gastrointestinal nematodes in ruminants. Extracts of native and exotic seed species from Brazil's semi-arid region were tested in vitro in an egg hatch assay and the bioactivity of their proteins was investigated. Each seed species was subjected to three extractions with three types of solvents. All the seeds showed ovicidal activity, which varied according to the solvents. Higher ovicidal activity was found in the molecule fractions of low molecular weight (0.05, Bonferroni test. Hemagglutinating activity was detected in the fractions of C. spectabilis and M. oleifera fractions, hemolysin activity in the A. lebbeck and M. oleifera fractions, serine protease inhibitory activity in the A. lebbeck, I. asarifolia, J. curcas, M. oleifera and R. communis fractions, cysteine protease inhibitor activity in the M. oleifera fraction, and no protein activity in the L. ferrea fraction. The results of this work reveal new plant species with a potential for use in controlling nematode parasites in goats, thus opening a new field of research involving plant protein molecules with ovicidal properties.

  13. Spontaneous complement activation on human B cells results in localized membrane depolarization and the clustering of complement receptor type 2 and C3 fragments

    DEFF Research Database (Denmark)

    Løbner, Morten; Leslie, Robert G Q; Prodinger, Wolfgang M

    2009-01-01

    While our previous studies have demonstrated that complement activation induced by complement receptors type 2 (CR2/CD21) and 1 (CR1/CD35) results in C3-fragment deposition and membrane attack complex (MAC) formation in human B cells, the consequences of these events for B-cell functions remain u...

  14. No activation of new initiation points for deoxyribonucleic acid replication in BALB/c 3T3 cells transformed by Kirsten sarcoma virus

    International Nuclear Information System (INIS)

    Oppenheim, A.; Horowitz, A.T.

    1981-01-01

    BALB/c 3T3 cells were transformed by Kirsten sarcoma virus, and five clones were isolated in soft agar. Average replicon sizes of the transformed cell lines were stimated by the method of fiber-autoradiography and found to be the same size as the nontransformed 3T3 cells, analyzed in parallel. The results indicate that, unlike simian virus 40 and Epstein-Barr virus, Kirsten sarcoma virus does not activate new initiation points for cellular deoxyribonucleic acid replication in murine sarcome virus-transformed BALB/c 3T3 cells

  15. Lectin typing of Campylobacter concisus

    DEFF Research Database (Denmark)

    Aabenhus, Rune Munck; Hynes, Sean O; Permin, Henrik

    2002-01-01

    A total of 44 clinical isolates and the type strain of the putative pathogen Campylobacter concisus were grouped based on their reactions with plant lectins. The optimized lectin typing system used C. concisus strains proteolytically pretreated and subsequently typed by using a panel of four...... lectins. The system grouped all 45 strains into 13 lectin reaction patterns, leaving no strain untypeable due to autoagglutination. Lectin types were both stable and reproducible....

  16. Atividades biológicas das lectinas PHA, WGA, jacalina e artocarpina Biological activities of PHA, WGA, jacalin and artocarpin lectins

    Directory of Open Access Journals (Sweden)

    Ana Maria Sell

    2000-05-01

    Full Text Available As lectinas são (glicoproteínas que se ligam a açúcares. O interesse destas moléculas na investigação científica se deve às diversas atividades biológicas a elas atribuídas. Além da identificação de grupos sangüíneos, da caracterização de microorganismos e da estimulação mitogênica de células imunes, as lectinas estão envolvidas nos processos de reconhecimento e das interações celulares. No presente trabalho, revisamos algumas atividades biológicas das lectinas PHA (fitohemaglutinina de Phaseolus vulgaris, WGA (aglutinina de germe de trigo, jacalina e artocarpina (lectinas de Artocarpus integrifolia. PHA, jacalina e artocarpina são mitogênicas para os linfócitos, estimulam a produção de citocinas endógenas, a atração e a ativação de leucócitos. WGA é uma lectina não-mitogênica, no entanto, modula a resposta de defesa estimulando a liberação de superóxido pelos neutrófilos. O entendimento das atividades biológicas permitirá o uso destas moléculas como uma ferramenta útil no diagnóstico e tratamento de muitas doenças.Lectins are ubiquitous (glycoproteins, which exhibit a specific and reversibly carbohydrate binding activity. Because of their structural complexity and variability, they can participate in many physiological functions. Besides the blood groups identification, microorganism characterization and mitogenic immune cell proliferation, they are involved in the cell recognition and cell-cell interaction. In the present work we revised some biological activities of the PHA (Phaseolus vulgaris phytohemagglutinin, WGA (wheat germ agglutinin, jacalin and artocarpin (Artocarpus integrifolia lectins. PHA, jacalin and artocarpin may stimulate lymphocyte proliferation, attract and activate mononuclear cells and stimulate endogenous citokines production. WGA is a nonmitogenic lectin, however it may stimulate neutrophil superoxide production. The understanding of the lectin biological activities may

  17. An efficient top-down approach for the fabrication of large-aspect-ratio g-C3N4 nanosheets with enhanced photocatalytic activities.

    Science.gov (United States)

    Tong, Jincheng; Zhang, Li; Li, Fei; Li, Mingming; Cao, Shaokui

    2015-09-28

    Graphitic carbon nitride (g-C3N4) nanosheets with large aspect ratios were fabricated from bulk g-C3N4 through an efficient top-down approach of moderate disintegration-exfoliation using diluted H2SO4 as an "efficient knife". By prior disintegration in a diluted H2SO4 solution, the exfoliation of bulk g-C3N4 was effectively accelerated. The as-prepared g-C3N4 nanosheets possess a two-dimensional (2D) thin-layer structure with seven-atom thickness, a large lateral size of about 1 μm, and a high specific surface area of 80 m(2) g(-1). Compared with the bulk precursor, the g-C3N4 nanosheets showed much higher efficiency of photogenerated charge transfer and separation, and consequently exhibited enhanced photocatalytic activity toward hydrogen evolution and pollutant decomposition under both full-sunlight and visible-light irradiation.

  18. Degradation of Acid Orange 7 by peroxymonosulfate activated with the recyclable nanocomposites of g-C3N4 modified magnetic carbon.

    Science.gov (United States)

    Guo, Furong; Lu, Jiahua; Liu, Qing; Zhang, Ping; Zhang, Aiqing; Cai, Yingjie; Wang, Qiang

    2018-08-01

    Carbon-based catalysts have attracted high attention since they are greener and cheaper, while magnetic nanomaterials are very useful in environmental application because of the easy recovery and operation given by the magnetic separability. Therefore, graphitic carbon nitride modified magnetic carbon nanocomposites Fe 3 O 4 @C/g-C 3 N 4 was prepared herein for the first time as a new carbon-based catalyst for the activation of peroxymonosulfate (PMS). The catalytic properties of Fe 3 O 4 @C/g-C 3 N 4 in activating PMS for the degradation of Acid Orange 7 (AO 7), a model organic pollutant, were investigated. AO 7 degradation efficiency was significantly enhanced after modification of Fe 3 O 4 @C with g-C 3 N 4 , and the composite Fe 3 O 4 @C/g-C 3 N 4 from loading of 5 wt% g-C 3 N 4 and calcined at 300 °C for 30 min exhibited the best performance. AO 7 could be efficiently decolorized using the "Fe 3 O 4 @C/C 3 N 4 (5%) + PSM" system within the pH range of 2-6, and 97% of AO 7 could be removed in 20 min without pH adjustment (pH = 4). Radical quenching and EPR studies confirmed that both sulfate and hydroxyl radicals produced from PMS activation were the active species responsible for the oxidation of AO 7. The degradation mechanism was suggested based on the experimental results and XPS analyses. It was proposed that the CO groups on the carbon surface of Fe 3 O 4 @C rather than the CO in g-C 3 N 4 played a key role as the active sites for PMS activation. The catalyst was magnetically separable and displayed good stability and reusability, thus providing a potentially green catalyst for sustainable remediation of organic pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Aberrant Receptor Internalization and Enhanced FRS2-dependent Signaling Contribute to the Transforming Activity of the Fibroblast Growth Factor Receptor 2 IIIb C3 Isoform*

    Science.gov (United States)

    Cha, Jiyoung Y.; Maddileti, Savitri; Mitin, Natalia; Harden, T. Kendall; Der, Channing J.

    2009-01-01

    Alternative splice variants of fibroblast growth factor receptor 2 (FGFR2) IIIb, designated C1, C2, and C3, possess progressive reduction in their cytoplasmic carboxyl termini (822, 788, and 769 residues, respectively), with preferential expression of the C2 and C3 isoforms in human cancers. We determined that the progressive deletion of carboxyl-terminal sequences correlated with increasing transforming potency. The highly transforming C3 variant lacks five tyrosine residues present in C1, and we determined that the loss of Tyr-770 alone enhanced FGFR2 IIIb C1 transforming activity. Because Tyr-770 may compose a putative YXXL sorting motif, we hypothesized that loss of Tyr-770 in the 770YXXL motif may cause disruption of FGFR2 IIIb C1 internalization and enhance transforming activity. Surprisingly, we found that mutation of Leu-773 but not Tyr-770 impaired receptor internalization and increased receptor stability and activation. Interestingly, concurrent mutations of Tyr-770 and Leu-773 caused 2-fold higher transforming activity than caused by the Y770F or L773A single mutations, suggesting loss of Tyr and Leu residues of the 770YXXL773 motif enhances FGFR2 IIIb transforming activity by distinct mechanisms. We also determined that loss of Tyr-770 caused persistent activation of FRS2 by enhancing FRS2 binding to FGFR2 IIIb. Furthermore, we found that FRS2 binding to FGFR2 IIIb is required for increased FRS2 tyrosine phosphorylation and enhanced transforming activity by Y770F mutation. Our data support a dual mechanism where deletion of the 770YXXL773 motif promotes FGFR2 IIIb C3 transforming activity by causing aberrant receptor recycling and stability and persistent FRS2-dependent signaling. PMID:19103595

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

    Science.gov (United States)

    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 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.

  1. Efficient visible-light photocatalytic oxidation of gaseous NO with graphitic carbon nitride (g–C_3N_4) activated by the alkaline hydrothermal treatment and mechanism analysis

    International Nuclear Information System (INIS)

    Nie, Haoyu; Ou, Man; Zhong, Qin; Zhang, Shule; Yu, Lemeng

    2015-01-01

    Highlights: • Various porous g–C_3N_4 samples were obtained by the alkaline hydrothermal treatment. • 0.12CN possesses the largest BET specific surface area and pore volume. • The NO conversion in the presence of 0.12CN reaches 40.4%. • Reasons for the enhanced PCO performance with treated g–C_3N_4 was analyzed. • Further mechanism of the PCO of NO relevant with active species was investigated. - Abstract: In this paper, an enhanced visible-light photocatalytic oxidation (PCO) of NO (∼400 ppm) in the presence of the graphitic carbon nitride (g–C_3N_4) treated by the alkaline hydrothermal treatment is evaluated. Various g–C_3N_4 samples were treated in different concentrations of NaOH solutions and the sample treated in 0.12 mol L"−"1 of NaOH solution possesses the largest BET specific surface area as well as the optimal ability of the PCO of NO. UV–vis diffuse reflection spectra (DRS) and photoluminescence (PL) spectra were also conducted, and the highly improved photocatalytic performance is ascribed to the large specific surface area and high pore volume, which provides more adsorption and active sites, the wide visible-light adsorption edge and the narrow band gap, which is favorable for visible-light activation, as well as the decreased recombination rate of photo-generated electrons and holes, which could contribute to the production of active species. Fluorescence spectra and a trapping experiment were conducted to further the mechanism analysis of the PCO of NO, illustrating that superoxide radicals (·O_2"−) play the dominant role among active species in the PCO of NO.

  2. Confined Catalysis in the g-C3N4/Pt(111) Interface: Feasible Molecule Intercalation, Tunable Molecule-Metal Interaction, and Enhanced Reaction Activity of CO Oxidation.

    Science.gov (United States)

    Wang, Shujiao; Feng, Yingxin; Yu, Ming'an; Wan, Qiang; Lin, Sen

    2017-09-27

    The deposition of a two-dimensional (2D) atomic nanosheet on a metal surface has been considered as a new route for tuning the molecule-metal interaction and surface reactivity in terms of the confinement effect. In this work, we use first-principles calculations to systematically explore a novel nanospace constructed by placing a 2D graphitic carbon nitride (g-C 3 N 4 ) nanosheet over a Pt(111) surface. The confined catalytic activity in this nanospace is investigated using CO oxidation as a model reaction. With the inherent triangular pores in the g-C 3 N 4 overlayer being taken advantage of, molecules such as CO and O 2 can diffuse to adsorb on the Pt(111) surface underneath the g-C 3 N 4 overlayer. Moreover, the mechanism of intercalation is also elucidated, and the results reveal that the energy barrier depends mainly on the properties of the molecule and the channel. Importantly, the molecule-catalyst interaction can be tuned by the g-C 3 N 4 overlayer, considerably reducing the adsorption energy of CO on Pt(111) and leading to enhanced reactivity in CO oxidation. This work will provide important insight for constructing a promising nanoreactor in which the following is observed: The molecule intercalation is facile; the molecule-metal interaction is efficiently tuned; the metal-catalyzed reaction is promoted.

  3. Mannose-binding lectin genetics: from A to Z

    DEFF Research Database (Denmark)

    Garred, Peter

    2008-01-01

    MBL (mannose-binding lectin) is primarily a liver-derived collagen-like serum protein. It binds sugar structures on micro-organisms and on dying host cells and is one of the four known mediators that initiate activation of the complement system via the lectin pathway. Common variant alleles situa...

  4. Morus alba Leaf Lectin (MLL) Sensitizes MCF-7 Cells to Anoikis by Inhibiting Fibronectin Mediated Integrin-FAK Signaling through Ras and Activation of P38 MAPK

    Science.gov (United States)

    Saranya, Jayaram; Shilpa, Ganesan; Raghu, Kozhiparambil G.; Priya, Sulochana

    2017-01-01

    Lectins are a unique class of carbohydrate binding proteins/glycoproteins, and many of them possess anticancer properties. They can induce cell cycle arrest and apoptosis, inhibit protein synthesis, telomerase activity and angiogenesis in cancer cells. In the present study, we have demonstrated the effect of Morus alba leaf lectin (MLL) on anoikis induction in MCF-7 cells. Anoikis induction in cancer cells has a significant role in preventing early stage metastasis. MLL treatment in monolayers of MCF-7 cells caused significant detachment of cells in a time and concentration dependent manner. The detached cells failed to re-adhere and grew even to culture plates coated with different matrix proteins. DNA fragmentation, membrane integrity studies, annexin V staining, caspase 9 activation and upregulation of Bax/Bad confirmed that the detached cells underwent apoptosis. Upregulation of matrix metalloproteinase 9 (MMP-9) caused a decrease in fibronectin (FN) production which facilitated the cells to detach by blocking the FN mediated downstream signaling. On treatment with MLL, we have observed downregulation of integrin expression, decreased phosphorylation of focal adhesion kinase (FAK), loss in FAK-integrin interaction and active Ras. MLL treatment downregulated the levels of phosphorylated Akt and PI3K. Also, we have studied the effect of MLL on two stress activated protein kinases p38 MAPK and JNK. p38 MAPK activation was found to be elevated, but there was no change in the level of JNK. Thus our study substantiated the possible antimetastatic effect of MLL by inducing anoikis in MCF-7 cells by activation of caspase 9 and proapoptotic Bax/Bad by blockage of FN mediated integrin/FAK signaling and partly by activation of p38 MAPK. PMID:28223935

  5. Mannose-binding lectin gene polymorphisms are associated with disease activity and physical disability in untreated, anti-cyclic citrullinated peptide-positive patients with early rheumatoid arthritis

    DEFF Research Database (Denmark)

    Jacobsen, Søren; Garred, Peter; Madsen, Hans Ole

    2009-01-01

    OBJECTIVE: To study the association between polymorphisms in the mannose-binding lectin gene (MBL2) and disease activity, physical disability, and joint erosions in patients with newly diagnosed rheumatoid arthritis (RA). METHODS: Patients with early RA (n=158) not previously treated with disease...... modifying antirheumatic drugs, participating in a treatment trial (CIMESTRA study) were examined at inclusion for MBL2 pooled structural genotypes (O/O, A/O, A/A), regulatory MBL2 promoter polymorphism in position -221 (XX, XY, YY), anti-cyclic citrullinated peptide 2 antibodies (anti-CCP2), disease...... activity by Disease Activity Score-28 (DAS28 score), physical disability by Health Assessment Questionnaire (HAQ) score, and erosive changes in hands and feet (Sharp-van der Heijde score). RESULTS: Eight patients were homozygous MBL2 defective (O/O), 101 belonged to an intermediate group, and 49 were MBL2...

  6. In folio study of carbonic anhydrase and Rubisco activities in higher C3 plants using 18O and mass spectrometry

    International Nuclear Information System (INIS)

    Peltier, G.; Despax, V.; Dimon, B.; Rumeau, D.; Tourneux, C.

    1994-01-01

    This document studies the effects of a mild water stress and carbonic anhydrase activity by ethoxyzolamide (EZA) on the diffusion of CO 2 in leaves, by 18 O labelling of O 2 and of CO 2 associated to mass spectrometry. (A.B.). 5 refs., 2 figs

  7. Room-temperature synthesis of nanoporous 1D microrods of graphitic carbon nitride (g-C3N4) with highly enhanced photocatalytic activity and stability.

    Science.gov (United States)

    Pawar, Rajendra C; Kang, Suhee; Park, Jung Hyun; Kim, Jong-Ho; Ahn, Sunghoon; Lee, Caroline S

    2016-08-08

    A one-dimensional (1D) nanostructure having a porous network is an exceptional photocatalytic material to generate hydrogen (H2) and decontaminate wastewater using solar energy. In this report, we synthesized nanoporous 1D microrods of graphitic carbon nitride (g-C3N4) via a facile and template-free chemical approach at room temperature. The use of concentrated acids induced etching and lift-off because of strong oxidation and protonation. Compared with the bulk g-C3N4, the porous 1D microrod structure showed five times higher photocatalytic degradation performance toward methylene blue dye (MB) under visible light irradiation. The photocatalytic H2 evolution of the 1D nanostructure (34 μmol g(-1)) was almost 26 times higher than that of the bulk g-C3N4 structure (1.26 μmol g(-1)). Additionally, the photocurrent stability of this nanoporous 1D morphology over 24 h indicated remarkable photocorrosion resistance. The improved photocatalytic activities were attributed to prolonged carrier lifetime because of its quantum confinement effect, effective separation and transport of charge carriers, and increased number of active sites from interconnected nanopores throughout the microrods. The present 1D nanostructure would be highly suited for photocatalytic water purification as well as water splitting devices. Finally, this facile and room temperature strategy to fabricate the nanostructures is very cost-effective.

  8. Constructing three-dimensional porous graphene-carbon quantum dots/g-C3N4 nanosheet aerogel metal-free photocatalyst with enhanced photocatalytic activity

    Science.gov (United States)

    He, Huijuan; Huang, Langhuan; Zhong, Zijun; Tan, Shaozao

    2018-05-01

    Photocatalysis has been widely considered to be an effective way for solving the worldwide environmental pollution issues. Herein, a new type of three-dimensional (3D) ternary graphene-carbon quantum dots/g-C3N4 nanosheet (GA-CQDs/CNN) aerogel visible-light-driven photocatalyst was synthesized via a two-step hydrothermal method. In this unique ternary photocatalyst, both carbon quantum dots (CQDs) and reduced graphene oxide (rGO) could improve the visible light absorption and promote the charge separation. Furthermore, reduced graphene oxide (rGO) could act as a supportor for the 3D framework. Such a ternary system overcame the drawbacks of bulk g-C3N4 (BCN) and achieved the enhanced photocatalytic activity and long-term stability. As a result, the methyl orange (MO) removal ratio of GA-CQDs/CNN-24% was up to 91.1%, which was about 7.6 times higher than that of bulk g-C3N4 (BCN) under the identical conditions. Moreover that GA-CQDs/CNN-24% exhibited inappreciable loss of photocatalytic activity after four-cycle degradation processes. Finally, the photocatalytic mechanism of GA-CQDs/CNN-24% was interpreted both theoretically and experimentally.

  9. The lectin-like domain of thrombomodulin confers protection from neutrophil-mediated tissue damage by suppressing adhesion molecule expression via nuclear factor kappaB and mitogen-activated protein kinase pathways

    NARCIS (Netherlands)

    Conway, Edward M.; van de Wouwer, Marlies; Pollefeyt, Saskia; Jurk, Kerstin; van Aken, Hugo; de Vriese, Astrid; Weitz, Jeffrey I.; Weiler, Hartmut; Hellings, Peter W.; Schaeffer, Paul; Herbert, Jean-Marc; Collen, Désiré; Theilmeier, Gregor

    2002-01-01

    Thrombomodulin (TM) is a vascular endothelial cell (EC) receptor that is a cofactor for thrombin-mediated activation of the anticoagulant protein C. The extracellular NH(2)-terminal domain of TM has homology to C-type lectins that are involved in immune regulation. Using transgenic mice that lack

  10. Microglial Lectins in Health and Neurological Diseases

    Directory of Open Access Journals (Sweden)

    Jian Jing Siew

    2018-05-01

    Full Text Available Microglia are the innate sentinels of the central nervous system (CNS and are responsible for the homeostasis and immune defense of the CNS. Under the influence of the local environment and cell-cell interaction, microglia exhibit a multidimensional and context-dependent phenotypes that can be cytotoxic and neuroprotective. Recent studies suggest that microglia express multitudinous types of lectins, including galectins, Siglecs, mannose-binding lectins (MBLs and other glycan binding proteins. Because most studies that examine lectins focus on the peripheral system, the functions of lectins have not been critically investigated in the CNS. In addition, the types of brain cells that contribute to the altered levels of lectins present in diseases are often unclear. In this review, we will discuss how galectins, Siglecs, selectins and MBLs contribute to the dynamic functions of microglia. The interacting ligands of these lectins are complex glycoconjugates, which consist of glycoproteins and glycolipids that are expressed on microglia or surrounding cells. The current understanding of the heterogeneity and functions of glycans in the brain is limited. Galectins are a group of pleotropic proteins that recognize both β-galactoside-containing glycans and non- β-galactoside-containing proteins. The function and regulation of galectins have been implicated in immunomodulation, neuroinflammation, apoptosis, phagocytosis and oxidative bursts. Most Siglecs are expressed at a low level on the plasma membrane and bind to sialic acid residues for immunosurveillance and cell-cell communication. Siglecs are classified based on their inhibitory and activatory downstream signaling properties. Inhibitory Siglecs negatively regulate microglia activation upon recognizing the intact sialic acid patterns and vice versa. MBLs are expressed upon infection in cytoplasm and can be secreted in order to recognize molecules containing terminal mannose as an innate immune

  11. Lectin affinity electrophoresis.

    Science.gov (United States)

    Kobayashi, Yuka

    2014-01-01

    An interaction or a binding event typically changes the electrophoretic properties of a molecule. Affinity electrophoresis methods detect changes in the electrophoretic pattern of molecules (mainly macromolecules) that occur as a result of biospecific interactions or complex formation. Lectin affinity electrophoresis is a very effective method for the detection and analysis of trace amounts of glycobiological substances. It is particularly useful for isolating and separating the glycoisomers of target molecules. Here, we describe a sensitive technique for the detection of glycoproteins separated by agarose gel-lectin affinity electrophoresis that uses antibody-affinity blotting. The technique is tested using α-fetoprotein with lectin (Lens culinaris agglutinin and Phaseolus vulgaris agglutinin)-agarose gels.

  12. Dual recognition activity of a rhamnose-binding lectin to pathogenic bacteria and zooxanthellae in stony coral Pocillopora damicornis.

    Science.gov (United States)

    Zhou, Zhi; Yu, Xiaopeng; Tang, Jia; Zhu, Yunjie; Chen, Guangmei; Guo, Liping; Huang, Bo

    2017-05-01

    Rhamnose-binding lectin (RBL) is a type of Ca 2+ -independent lectin with tandem repeat carbohydrate-recognition domain, and is crucial for the innate immunity in many invertebrates. In this study, the cDNA sequence encoding RBL in coral Pocillopora damicornis (PdRBL-1) was cloned. The PdRBL-1 protein shared highest amino acid sequence similarity (55%) with the polyp of Hydra vulgaris, and contained a signal peptide and two tandem carbohydrate-recognition domains in which all cysteine residues were conserved. Surface plasmon resonance method revealed that the recombinant PdRBL-1 protein bound to LPS and Lipid A, but not to LTA, β-glucan, mannose and Poly (I:C). Results also showed that it bonded with zooxanthellae using western blotting method, and that the bound protein was detectable only at concentrations higher than 10 2 zooxanthellae cell mL -1 . When recombinant PdRBL-1 protein was preincubated with LPS, lower amounts of protein bound to zooxanthellae compared to cells not preincubated with LPS. Furthermore, PdRBL-1 mRNA expression increased significantly at 12 h, and declined to the baseline at 24 h after heat stress at 31 °C. These results collectively suggest that PdRBL-1 could recognize not only pathogenic bacteria but also symbiotic zooxanthellae, and that the recognition of zooxanthellae by PdRBL-1 could be repressed by pathogenic bacteria through competitive binding. This information allows us to gain new insights in the mechanisms influencing the establishment and maintenance of coral-zooxanthella symbiosis in coral P. damicornis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. A label-free photoelectrochemical biosensor for urokinase-type plasminogen activator detection based on a g-C3N4/CdS nanocomposite.

    Science.gov (United States)

    Liu, Xing-Pei; Chen, Jing-Shuai; Mao, Chang-Jie; Niu, He-Lin; Song, Ji-Ming; Jin, Bao-Kang

    2018-09-26

    Herein, we established a novel ultrasensitive photoelectrochemical biosensor for detecting urokinase-type plasminogen activator (u-PA), based on a g-C 3 N 4 /CdS nanocomposite. The prepared nanocomposite was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible absorption spectroscopy, and Fourier transform infrared spectroscopy, thus indicating that the nanocomposite was prepared successfully. In the typical process, the prepared nanocomposite was deposited on the surface of a bare FTO electrode. After being air-dried, the g-C 3 N 4 /CdS nanocomposite modified electrode was successively incubated with antibody against urokinase-type plasminogen activator and the blocking agent BSA to produce a photoelectrochemical biosensor for u-PA. In the presence of target u-PA antigen, the photocurrent response of the prepared biosensor electrode decreased significantly. The proposed novel photoelectrochemical biosensor exhibited good sensitivity, specificity, and reproducibility for u-PA detection, and a low detection limit of 33 fg mL -1 , ranging from 1 μg mL -1 -0.1 pg mL -1 . The proposed strategy should provide a promising method for detection of other biomarkers. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Facile Synthesis of g-C3N4 Nanosheets/ZnO Nanocomposites with Enhanced Photocatalytic Activity in Reduction of Aqueous Chromium(VI under Visible Light

    Directory of Open Access Journals (Sweden)

    Xiaoya Yuan

    2016-09-01

    Full Text Available Graphitic-C3N4 nanosheets (CN/ZnO photocatalysts (CN/ZnO with different CN loadings were successfully prepared via a simple precipitation-calcination in the presence of exfoliated C3N4 nanosheets. Their morphology and structure were thoroughly characterized by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, high-resolution transmission electron microscopy (HRTEM, X-ray photoelectron spectroscopy (XPS, UV-Vis diffuse reflectance spectroscopy (DRS and photoluminescence spectra (PL. The results showed that hexagonal wurzite-phase ZnO nanoparticles were randomly distributed onto the CN nanosheets with a well-bonded interface between the two components in the CN/ZnO composites. The performance of the photocatalytic Cr(VI reduction indicated that CN/ZnO exhibited better photocatalytic activity than pure ZnO under visible-light irradiation and the photocatalyst composite with a lower loading of CN sheets eventually displayed higher activity. The enhanced performance of CN/ZnO photocatalysts could be ascribed to the increased absorption of the visible light and the effective transfer and separation of the photogenerated charge carriers.

  15. Enhancement of the ALP activity of C3H10T1/2 cells by the combination of an oxysterol and apatite

    International Nuclear Information System (INIS)

    Son, Kyung Mi; Park, Hee Chul; Kim, Na Ryoung; Yang, Hyeong-Cheol; Lee, In-Seop

    2010-01-01

    Biomimetic apatite coating has been used to load osteogenic biomolecules onto the surface of titanium implants. Apatite on the surface of biomaterials is thought to function as a reservoir of biomolecules as well as enhancing osteoconductivity. In this study, 20α-hydroxycholesterol (20α-HC), an osteogenic oxysterol, was used to induce differentiation of a mouse embryo fibroblast cell line (C3H10T1/2) by loading the oxysterol on biomimetically coated apatite of titanium discs. We found that the phosphatase (alkaline phosphatase (ALP)) activity of 20α-HC was significantly higher with ascorbic acid than alone, suggesting a need for ascorbic acid as a co-factor. When 20α-HC was added into the apatite coating solution, the ALP activity of the C3H10T1/2 cells did not increase on the apatite surface, even in the presence of ascorbic acid. However, ALP activity increased dramatically when 20α-HC was loaded by volatilization of EtOH from the apatite coat after dipping discs in 20α-HC-dissolved EtOH. Interestingly, ascorbic acid was not needed for this increase in ALP activity, suggesting a synergistic effect of 20α-HC and apatite. The concentration of calcium ions, a major component of apatite, affected the osteogenic effect of 20α-HC, and the increase in ALP activity was attenuated by L-type calcium channel inhibitors, verapamil and nifedipine. These results demonstrate that calcium ions released from apatite are important in the synergistic effect of 20α-HC and apatite.

  16. High-Mannose Specific Lectin and Its Recombinants from a Carrageenophyta Kappaphycus alvarezii Represent a Potent Anti-HIV Activity Through High-Affinity Binding to the Viral Envelope Glycoprotein gp120.

    Science.gov (United States)

    Hirayama, Makoto; Shibata, Hiromi; Imamura, Koji; Sakaguchi, Takemasa; Hori, Kanji

    2016-02-01

    We previously reported that a high-mannose binding lectin KAA-2 from the red alga Kappaphycus alvarezii, which is an economically important species and widely cultivated as a source of carrageenans, had a potent anti-influenza virus activity. In this study, the full-length sequences of two KAA isoforms, KAA-1 and KAA-2, were elucidated by a combination of peptide mapping and complementary DNA (cDNA) cloning. They consisted of four internal tandem-repeated domains, which are conserved in high-mannose specific lectins from lower organisms, including a cyanobacterium Oscillatoria agardhii and a red alga Eucheuma serra. Using an Escherichia coli expression system, an active recombinant form of KAA-1 (His-tagged rKAA-1) was successfully generated in the yield of 115 mg per liter of culture. In a detailed oligosaccharide binding analysis by a centrifugal ultrafiltration-HPLC method with 27 pyridylaminated oligosaccharides, His-tagged rKAA-1 and rKAA-1 specifically bound to high-mannose N-glycans with an exposed α1-3 mannose in the D2 arm as the native lectin did. Predicted from oligosaccharide binding specificity, a surface plasmon resonance analysis revealed that the recombinants exhibit strong interaction with gp120, a heavily glycosylated envelope glycoprotein of HIV with high association constants (1.48 - 1.61 × 10(9) M(-1)). Native KAAs and the recombinants inhibited the HIV-1 entry at IC50s of low nanomolar levels (7.3-12.9 nM). Thus, the recombinant proteins would be useful as antiviral reagents targeting the viral surface glycoproteins with high-mannose N-glycans, and the cultivated alga K. alvarezii could also be a good source of not only carrageenans but also this functional lectin(s).

  17. Ternary composite of TiO2 nanotubes/Ti plates modified by g-C3N4 and SnO2 with enhanced photocatalytic activity for enhancing antibacterial and photocatalytic activity.

    Science.gov (United States)

    Faraji, Masoud; Mohaghegh, Neda; Abedini, Amir

    2018-01-01

    A series of g-C 3 N 4 -SnO 2 /TiO 2 nanotubes/Ti plates were fabricated via simple dipping of TiO 2 nanotubes/Ti in a solution containing SnCl 2 and g-C 3 N 4 nanosheets and finally annealing of the plates. Synthesized plates were characterized by various techniques. The SEM analysis revealed that the g-C 3 N 4 -SnO 2 nanosheets with high physical stability have been successfully deposited onto the surface of TiO 2 nanotubes/Ti plate. Photocatalytic activity was investigated using two probe chemical reactions: oxidative decomposition of acetic acid and oxidation of 2-propanol under irradiation. Antibacterial activities for Escherichia coli (E. coli) bacteria were also investigated in dark and under UV/Vis illuminations. Detailed characterization and results of photocatalytic and antibacterial activity tests revealed that semiconductor coupling significantly affected the photocatalyst properties synthesized and hence their photocatalytic and antibacterial activities. Modification of TiO 2 nanotubes/Ti plates with g-C 3 N 4 -SnO 2 deposits resulted in enhanced photocatalytic activities in both chemical and microbial systems. The g-C 3 N 4 -SnO 2 /TiO 2 nanotubes/Ti plate exhibited the highest photocatalytic and antibacterial activity, probably due to the heterojunction between g-C 3 N 4 -SnO 2 and TiO 2 nanotubes/Ti in the ternary composite plate and thus lower electron/hole recombination rate. Based on the obtained results, a photocatalytic and an antibacterial mechanism for the degradation of E. coli bacteria and chemical pollutants over g-C 3 N 4 -SnO 2 /TiO 2 nanotubes/Ti plate were proposed and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Association of C-Type Lectin Mincle with FcεRIβγ Subunits Leads to Functional Activation of RBL-2H3 Cells through Syk.

    Science.gov (United States)

    Honjoh, Chisato; Chihara, Kazuyasu; Yoshiki, Hatsumi; Yamauchi, Shota; Takeuchi, Kenji; Kato, Yuji; Hida, Yukio; Ishizuka, Tamotsu; Sada, Kiyonao

    2017-04-10

    Macrophage-inducible C-type lectin (Mincle) interacts with the γ-subunit of high-affinity IgE receptor (FcεRIγ) and activates Syk by recognizing its specific ligand, trehalose-6,6'-dimycolate, a glycolipid produced by Mycobacterium tuberculosis. It has been suggested that mast cells participate in the immune defense against pathogenic microbes including M. tuberculosis, although the functions are still uncertain. In this study, we examined the Mincle-mediated signaling pathway and cellular responses using RBL-2H3 cells. Mincle formed a protein complex with not only FcεRIγ but also FcεRIβ in a stable cell line expressing myc-tagged Mincle. In addition, engagement of Mincle increased the levels of protein tyrosine phosphorylation and ERK phosphorylation. A pull-down assay demonstrated that cross-linking of Mincle induced binding of FcεRIβγ subunits to the Src homology 2 domain of Syk. Pharmacological and genetic studies indicated that activation of Syk was critical for Mincle-mediated activation of phospholipase Cγ2, leading to the activation of ERK and nuclear factor of activated T cells. Moreover, engagement of Mincle efficiently induced up-regulation of characteristic mast cell genes in addition to degranulation. Taken together, our present results suggest that mast cells contribute to Mincle-mediated immunity through Syk activation triggered by association with the FcεRIβγ complex.

  19. Proliferative Activity of Mammary Carcinoma Cells by AgNOR Count in C3H mice Receiving Ethanol Extract of Sponge Haliclona sp

    Science.gov (United States)

    Sijabat, Lanceria; Susilaningsih, Neni; Trianto, Agus; Murwani, Retno

    2018-02-01

    Quantification of argyrophilic nucleolar organizer region (AgNORs) was considered as one of markers of proliferative activity of cancer cells. Sponge Haliclona sp extract contains anticancer bioactive compounds and our previous study showed that the extract was able to improve histological grade of induced mammary adenocarcinoma in mice. The following research was conducted to study the extract administration on the proliferative activity of the carcinoma cells represented by AgNOR count in mice. This experimental study applied post test only control group design. Twenty C3H mice were divided into four groups namely C (control), H1, H2 and H3. Each group was given 0, 0.15, 1.5, and 15 mg Haliclona sp extract respectively. After three weeks of extract administration, mice were inoculated with breast cancer cells from donor mice. The extract administration were continued for another three weeks. AgNOR count was performed on tumor sections and expressed as mean of AgNOR (mAgNOR) and percentage of AgNOR (pAgNOR). Means of mAgNOR in C, H1, H2 and H3 were 4.070, 3.195, 3.450, and 3.190 respectively. Means of pAgNOR in C, H1, H2 and H3 were 34,40, 25,40, 38,40 and 19,80 respectively. The lowest means of mAgNOR and pAgNOR which is an indication of lower proliferative activity of the cancer cells was found in H3. However no significant difference can be found among treatment groups (p>0.05). Using AgNOR count, the ethanol extract of Haliclona sp could not show significant reduction in proliferation of mammary carcinoma cells of C3H mice. This finding support the view that AgNOR alone could not be used to determine pathology of cancer cells.

  20. Recombinant protein expression of Moringa oleifera lectin in methylotrophic yeast as active coagulant for sustainable high turbid water treatment.

    Science.gov (United States)

    Abd Wahid, Muhamad Azhar; Megat Mohd Noor, Megat Johari; Goto, Masafumi; Sugiura, Norio; Othman, Nor'azizi; Zakaria, Zuriati; Ahmad Mohammed, Thamer; Jusoh, Ahmad; Hara, Hirofumi

    2017-08-01

    The natural coagulant Moringa oleifera lectin (MoL) as cationic protein is a promising candidate in coagulation process of water treatment plant. Introducing the gene encoding MoL into a host, Pichia pastoris, to secrete soluble recombinant protein is assessed in this study. Initial screening using PCR confirmed the insertion of MoL gene, and SDS-PAGE analysis detected the MoL protein at 8 kDa. Cultured optimization showed the highest MoL protein at 520 mg/L was observed at 28 °C for 144 h of culturing by induction in 1% methanol. Approximately, 0.40 mg/mL of recombinant MoL protein showed 95 ± 2% turbidity removal of 1% kaolin suspension. In 0.1% kaolin suspension, the concentration of MoL at 10 μg/mL exhibits the highest turbidity reduction at 68 ± 1%. Thus, recombinant MoL protein from P. pastoris is an effective coagulant for water treatment.

  1. The non-receptor tyrosine kinase Lyn controls neutrophil adhesion by recruiting the CrkL–C3G complex and activating Rap1 at the leading edge

    Science.gov (United States)

    He, Yuan; Kapoor, Ashish; Cook, Sara; Liu, Shubai; Xiang, Yang; Rao, Christopher V.; Kenis, Paul J. A.; Wang, Fei

    2011-01-01

    Establishing new adhesions at the extended leading edges of motile cells is essential for stable polarity and persistent motility. Despite recent identification of signaling pathways that mediate polarity and chemotaxis in neutrophils, little is known about molecular mechanisms governing cell–extracellular-matrix (ECM) adhesion in these highly polarized and rapidly migrating cells. Here, we describe a signaling pathway in neutrophils that is essential for localized integrin activation, leading edge attachment and persistent migration during chemotaxis. This pathway depends upon Gi-protein-mediated activation and leading edge recruitment of Lyn, a non-receptor tyrosine kinase belonging to the Src kinase family. We identified the small GTPase Rap1 as a major downstream effector of Lyn to regulate neutrophil adhesion during chemotaxis. Depletion of Lyn in neutrophil-like HL-60 cells prevented chemoattractant-induced Rap1 activation at the leading edge of the cell, whereas ectopic expression of Rap1 largely rescued the defects induced by Lyn depletion. Furthermore, Lyn controls spatial activation of Rap1 by recruiting the CrkL–C3G protein complex to the leading edge. Together, these results provide novel mechanistic insights into the poorly understood signaling network that controls leading edge adhesion during chemotaxis of neutrophils, and possibly other amoeboid cells. PMID:21628423

  2. Animal lectins: potential receptors for ginseng polysaccharides

    Directory of Open Access Journals (Sweden)

    So Hee Loh

    2017-01-01

    Full Text Available Panax ginseng Meyer, belonging to the genus Panax of the family Araliaceae, is known for its human immune system-related effects, such as immune-boosting effects. Ginseng polysaccharides (GPs are the responsible ingredient of ginseng in immunomodulation, and are classified as acidic and neutral GPs. Although GPs participate in various immune reactions including the stimulation of immune cells and production of cytokines, the precise function of GPs together with its potential receptor(s and their signal transduction pathways have remained largely unknown. Animal lectins are carbohydrate-binding proteins that are highly specific for sugar moieties. Among many different biological functions in vivo, animal lectins especially play important roles in the immune system by recognizing carbohydrates that are found exclusively on pathogens or that are inaccessible on host cells. This review summarizes the immunological activities of GPs and the diverse roles of animal lectins in the immune system, suggesting the possibility of animal lectins as the potential receptor candidates of GPs and giving insights into the development of GPs as therapeutic biomaterials for many immunological diseases.

  3. Natural lectin activity in the haemolymph of Panstrogylus megistus (Heteroptera: Reduvidae Atividade lectínica na hemolinfa de Panstrongylus megistus (Heteroptera: Reduviidae

    Directory of Open Access Journals (Sweden)

    Y. M. Gomes

    1988-12-01

    Full Text Available The haemolymph of Panstrongylus megistus showed a natural lectin activity for a wide range of vertebrate erythocytes. Agglutination was observed against all vertebrate erythrocytes tested (human ABO, duck, rabbit, mouse, sheep, chicken and cow. Cow erythrocytes showed the lowest titre. Concerning human erythrocytes, the lectin activity was similar in the types A+,B+ and AB+ while the highest activity was observed in the type O+. Determination of minimal inhibitory concentrations was carried out with human erythrocytes type O+. Agglutination was inhibited by several carbohydrates (rhamnose. D-galatose, raffinose, D-lactose and D-fucose. Rhamnose wasreported as the strongest inhibitor (0.78mM. The results suggest the presence of more than one lection in the haemolymph of P. megistus.A hemolinfa de Panstrongylus megistus mostrou uma atividade lectínica natural para eritrócitos de vários vertebrados e não mostrou especificidade para os diversos tipos de eritrócitos testados (humano ABO, pato, coelho,c amundongo,carneiro, galinha e boi. Com relação aos eritrócitos humanos a atividade lectínica foi similar nos tipos A+, B+ e AB+ enquanto a atividade mais alta foi observada no tipo O+. O título de aglutinação entre eritrócitos animais não mostrou diferença apreciável, excluindo eritrócitos de boi, que apresentaram o título mmais baixo. A determinação da concentração mínima de inibição foi realizada com eritrócitos humanos O+. A aglutinação foi inibida por vários carboidratos (ramnose, D-dalactose, rafinose, D-lactose e D-fucose. A ramnose foi o inibidor mais potente (0,78 mM. Os resultados sugerem a presença de mais de uma lectina na hemolinfa de P. megistus.

  4. Aberrant Receptor Internalization and Enhanced FRS2-dependent Signaling Contribute to the Transforming Activity of the Fibroblast Growth Factor Receptor 2 IIIb C3 Isoform*

    OpenAIRE

    Cha, Jiyoung Y.; Maddileti, Savitri; Mitin, Natalia; Harden, T. Kendall; Der, Channing J.

    2009-01-01

    Alternative splice variants of fibroblast growth factor receptor 2 (FGFR2) IIIb, designated C1, C2, and C3, possess progressive reduction in their cytoplasmic carboxyl termini (822, 788, and 769 residues, respectively), with preferential expression of the C2 and C3 isoforms in human cancers. We determined that the progressive deletion of carboxyl-terminal sequences correlated with increasing transforming potency. The highly transforming C3 variant lacks five tyrosine r...

  5. C3G knock-down enhances migration and invasion by increasing Rap1-mediated p38α activation, while it impairs tumor growth through p38α-independent mechanisms

    Science.gov (United States)

    Priego, Neibla; Arechederra, María; Sequera, Celia; Bragado, Paloma; Vázquez-Carballo, Ana; Gutiérrez-Uzquiza, Álvaro; Martín-Granado, Víctor; Ventura, Juan José; Kazanietz, Marcelo G.; Guerrero, Carmen; Porras, Almudena

    2016-01-01

    C3G, a Guanine nucleotide Exchange Factor (GEF) for Rap1 and R-Ras, has been shown to play important roles in development and cancer. Previous studies determined that C3G regulates cell death through down-regulation of p38α MAPK activity. Here, we found that C3G knock-down in MEFs and HCT116 cells promotes migration and invasion through Rap1-mediated p38α hyper-activation. These effects of C3G were inhibited by Rap1 knock-down or inactivation. The enhanced migration observed in C3G depleted HCT116 cells was associated with reduction in E-cadherin expression, internalization of ZO-1, actin cytoskeleton reorganization and decreased adhesion. We also found that matrix metalloproteases MMP2 and MMP9 are involved in the pro-invasive effect of C3G down-regulation. Additionally, our studies revealed that both C3G and p38α collaborate to promote growth of HCT116 cells in vitro and in vivo, possibly by enhancing cell survival. In fact, knocking-down C3G or p38α individually or together promoted cell death in vitro, although only the double C3G-p38α silencing was able to increase cell death within tumors. Notably, we found that the pro-tumorigenic function of C3G does not depend on p38α or Rap1 activation. Altogether, our studies uncover novel mechanisms by which C3G controls key aspects of tumorigenesis. PMID:27286263

  6. High molecular weight lectin isolated from the mucus of the giant African snail Achatina fulica.

    Science.gov (United States)

    Ito, Shigeru; Shimizu, Masahiro; Nagatsuka, Maki; Kitajima, Seiji; Honda, Michiyo; Tsuchiya, Takahide; Kanzawa, Nobuyuki

    2011-01-01

    To understand better the host defense mechanisms of mollusks against pathogens, we examined the anti-microbial activity of mucus from the giant African snail Achatina fulica. Hemagglutination activity of the mucus secreted by the integument of snails inoculated with Escherichia coli was observed to increase and to cause hemagglutination of rabbit red blood cells. Purification of the snail mucus lectin by sequential column chromatography revealed that the relative molecular mass of the lectin was 350 kDa. The hemagglutination activity of the lectin was Ca(2+)-dependent and was inhibited by galactose. Growth arrest tests showed that the lectin did not inhibit bacterial growth, but did induce agglutination of gram-positive and gram-negative bacteria. Tissue distribution analyses using a polyclonal antibody revealed that the lectin was expressed in the tissues of the mantle collar. The lectin isolated from the mucus of the snail appeared to contribute to its innate immunity.

  7. Construction of RGO/CdIn2S4/g-C3N4 ternary hybrid with enhanced photocatalytic activity for the degradation of tetracycline hydrochloride

    Science.gov (United States)

    Xiao, Peng; Jiang, Deli; Ju, Lixin; Jing, Junjie; Chen, Min

    2018-03-01

    Although RGO shows great advantage in promoting charge separation and transfer of semiconductor, construction of an efficient RGO-incorporated photocatalyst is still challenging. Herein, RGO was employed to construct novel RGO/CdIn2S4/g-C3N4 (donated as RGO/CIS/CN) ternary photocatalyst by a facile hydrothermal method for the degradation of tetracycline hydrochloride (TC). The RGO/CIS/CN ternary photocatalyst showed significantly enhanced photocatalytic activity towards the degradation of TC as compared to the binary CIS/CN, CIS/CN, and CN/RGO. The photoluminescence and photocurrent response results indicate that this enhanced photocatalytic activity can be mainly ascribed to the improved charge separation and transfer efficiency. Based on the radical trapping and electron spin resonance results, the superoxide radicals and holes are proposed to play an important role in the degradation of TC over RGO/CIS/CN ternary photocatalyst. This work paves new opportunities for the synthesis of RGO-incorporated ternary photocatalyst as an efficient photocatalyst for the degradation of organic contaminant.

  8. A weak-light-responsive TiO2/g-C3N4 composite film: photocatalytic activity under low-intensity light irradiation.

    Science.gov (United States)

    Wang, Peifang; Guo, Xiang; Rao, Lei; Wang, Chao; Guo, Yong; Zhang, Lixin

    2018-05-10

    A TiO 2 /g-C 3 N 4 composite photocatalytic film was prepared by in situ synthesis method and its photocatalytic capability under weak-visible-light condition was studied. The co-precursor with different ratio of melamine and TiO 2 sol-gel precursor were treated using ultrasonic mixing, physical deposition, and co-sintering method to form the smooth, white-yellow, and compact TiO 2 /g-C 3 N 4 composite films. The prepared TiO 2 /g-C 3 N 4 materials were characterized by SEM, TEM, EDS, XRD, BET, VBXPS, and UV-vis diffuse reflectance spectra. The results of composite showed that TiO 2 and g-C 3 N 4 have close interfacial connections which are favorable to charge transfer between these two semiconductors with suitable band structure, g-C 3 N 4 retard the anatase-to-rutile phase transition of TiO 2 significantly, the specific surface area were increased with g-C 3 N 4 ratio raised. Under weak-light irradiation, composite films photocatalytic experiments exhibited RhB removal efficiency approaching 90% after three recycles. Powders suspension degradation experiments revealed the removal efficiency of TiO 2 /g-C 3 N 4 (90.8%) was higher than pure TiO 2 (52.1%) and slightly lower than pure g-C 3 N 4 (96.6%). By control experiment, the enhanced photocatalysis is ascribed to the combination of TiO 2 and g-C 3 N 4 , which not only produced thin films with greater stability but also formed heterojunctions that can be favorable to charge transfer between these two semiconductors with suitable band structure. This study presents the potential application of photocatalytic film in the wastewater treatment under weak-light situation.

  9. Antimicrobial lectin from Schinus terebinthifolius leaf.

    Science.gov (United States)

    Gomes, F S; Procópio, T F; Napoleão, T H; Coelho, L C B B; Paiva, P M G

    2013-03-01

    Schinus terebinthifolius leaves are used for treating human diseases caused by micro-organisms. This work reports the isolation, characterization and antimicrobial activity of S. terebinthifolius leaf lectin (SteLL). The isolation procedure involved protein extraction with 0.15 mol l(-1) NaCl, filtration through activated charcoal and chromatography of the filtrate on a chitin column. SteLL is a 14-kDa glycopeptide with haemagglutinating activity that is inhibited by N-acetyl-glucosamine, not affected by ions (Ca(2+) and Mg(2+)) and stable upon heating (30-100 °C) as well as over the pH 5.0-8.0. The antimicrobial effect of SteLL was evaluated by determining the minimal inhibitory (MIC), bactericide (MBC) and fungicide (MFC) concentrations. Lectin was active against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteritidis and Staphylococcus aureus. Highest bacteriostatic and bactericide effects were detected for Salm. enteritidis (MIC: 0.45 μg ml(-1)) and Staph. aureus (MBC: 7.18 μg ml(-1)), respectively. SteLL impaired the growth (MIC: 6.5 μg ml(-1)) and survival (MFC: 26 μg ml(-1)) of Candida albicans. SteLL, a chitin-binding lectin, purified in milligram quantities, showed antimicrobial activity against medically important bacteria and fungi. SteLL can be considered as a new biomaterial for potential antimicrobial applications. © 2012 The Society for Applied Microbiology.

  10. Oral Administration of Heat-Killed Mycobacterium manresensis Delays Progression toward Active Tuberculosis in C3HeB/FeJ Mice.

    Science.gov (United States)

    Cardona, Paula; Marzo-Escartín, Elena; Tapia, Gustavo; Díaz, Jorge; García, Vanessa; Varela, Ismael; Vilaplana, Cristina; Cardona, Pere-Joan

    2015-01-01

    Low-dose tolerance using heat-killed mycobacteria has been tested as a means of stopping progression toward active tuberculosis (TB) lesions in a human-like murine model using C3HeB/FeJ mice. In the present study, we studied the effect of different treatment schedules with heat-killed non-tuberculous-mycobacteria (NTM) species when given orally, based on the hypothesis of generating oral tolerance. This study included M. manresensis, a new species belonging to the fortuitum group, present in drinking water. Oral treatment with M. manresensis for 2 weeks was able to induce a PPD-specific Tregs population, which has been related to a decrease in the neutrophilic infiltration found in TB lesions. Further mechanistic analysis using PPD-stimulated splenocytes links this 2-week treatment with heat-killed M. manresensis to IL-10 production and memory PPD-specific Tregs, and also to a weak PPD-specific global immune response stimulation, increasing IL-6, TNF, and IFN-γ production. In lungs, this treatment decreased the bacillary load, granulomatous infiltration and pro-inflammatory cytokines (TNF, IFN-γ, IL-6, and IL-17). Oral administration of M. manresensis during standard treatment for TB also significantly reduced the relapse of active TB after ending the treatment. Overall the data suggest that the use of heat-killed M. manresensis could be a new and promising tool for avoiding active TB induction and as adjunctive to TB treatment. This supports the usefulness of generating a new kind of protection based on a complex balanced immune response focused on both destroying the bacilli and including control of an excessive inflammatory response.

  11. Probing π-π stacking modulation of g-C3N4/graphene heterojunctions and corresponding role of graphene on photocatalytic activity.

    Science.gov (United States)

    Ma, Xinguo; Wei, Yang; Wei, Zhen; He, Hua; Huang, Chuyun; Zhu, Yongfa

    2017-12-15

    The photoelectrochemical properties of g-C 3 N 4 sheet are modified by the π-π stacking interaction with graphene, and the corresponding role of graphene on the surface chemical reactions is investigated by density functional theory. The calculated cohesive energies and the lattice mismatch energies indicate that g-C 3 N 4 and graphene are in parallel contact and can form a stable heterojunction. According to our calculated energy band structures and work functions of g-C 3 N 4 /graphene heterojunctions, the band edge modulations by graphene are discussed and corresponding photoinduced charge transfer processes are analyzed in detail. It is found that the incorporating of graphene into g-C 3 N 4 facilitates the separation of photoinduced e - /h + pairs and the oxidation capacity enhancement of the photoinduced holes with the downshifting of the valence band edge of g-C 3 N 4 layer. It is identified that the inhomogeneous onsite energies between interlayer and the band edge modulations are induced by the inhomogeneous charge redistribution between interlayer caused by graphene. Further, the initial dynamic reaction processes of oxygen atoms in g-C 3 N 4 /graphene heterojunctions also confirm the significant role of graphene on the surface chemical reactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. The third dimension of reading the sugar code by lectins: design of glycoclusters with cyclic scaffolds as tools with the aim to define correlations between spatial presentation and activity.

    Science.gov (United States)

    Murphy, Paul V; André, Sabine; Gabius, Hans-Joachim

    2013-04-04

    Coding of biological information is not confined to nucleic acids and proteins. Endowed with the highest level of structural versatility among biomolecules, the glycan chains of cellular glycoconjugates are well-suited to generate molecular messages/signals in a minimum of space. The sequence and shape of oligosaccharides as well as spatial aspects of multivalent presentation are assumed to underlie the natural specificity/selectivity that cellular glycans have for endogenous lectins. In order to eventually unravel structure-activity profiles cyclic scaffolds have been used as platforms to produce glycoclusters and afford valuable tools. Using adhesion/growth-regulatory galectins and the pan-galectin ligand lactose as a model, emerging insights into the potential of cyclodextrins, cyclic peptides, calixarenes and glycophanes for this purpose are presented herein. The systematic testing of lectin panels with spatially defined ligand presentations can be considered as a biomimetic means to help clarify the mechanisms, which lead to the exquisite accuracy at which endogenous lectins select their physiological counterreceptors from the complexity of the cellular glycome.

  13. Graphitic-C(3)N(4)-hybridized TiO(2) nanosheets with reactive {001} facets to enhance the UV- and visible-light photocatalytic activity.

    Science.gov (United States)

    Gu, Liuan; Wang, Jingyu; Zou, Zhijuan; Han, Xijiang

    2014-03-15

    AnataseTiO(2)nanosheets with dominant {001} facets were hybridized with graphitic carbon nitride (g-C(3)N(4)) using a facile solvent evaporation method. On top of the superior photocatalytic performance of highly reactive {001} facets, the hybridization with g-C(3)N(4) is confirmed to further improve the reactivity through degrading a series of organic molecules under both UV- and visible-light irradiation. It is proposed that an effective charge separation between g-C(3)N(4) and TiO2 exists in the photocatalytic process, i.e., the transferring of photogenerated holes from the valence band (VB) of TiO(2) to the highest occupied molecular orbital (HOMO) of g-C(3)N(4), and the injecting of electrons from the lowest unoccupied molecular orbital (LUMO) of g-C(3)N(4) to the conduction band (CB) of TiO(2). Due to this synergistic effect, the enhancement of UV- and visible-light photoactivity over the hybrid is achieved. Furthermore, it has been revealed that holes were the main factor for the improved photoactivity under UV-light, while the OH radicals gained the predominance for degrading organic molecules under visible-light. Overall, this work would be significant for fabricating efficient UV-/visible-photocatalysts and providing deeper insight into the enhanced mechanisms of π-conjugated molecules hybridized semiconductors. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Enhancement of acid treated g-C3N4sbnd Cu2O photocatalytic activity by PEG under visible light irradiation

    Science.gov (United States)

    Zuo, Shiyu; Xu, Haiming; Liao, Wei; Sun, Lei; Li, Qiang; Zan, Jie; Zhang, Binyang; Li, Dongya; Xia, Dongsheng

    2018-05-01

    In this study, g-C3N4sbnd Cu2O was successfully synthesized in the presence of PEG-400 surfactant via an acid treatment hydrothermal method and a high-temperature calcination method. The structures and properties of as-synthesized samples were characterized using a range of techniques, such as XPS, TEM, PL and BET. The g-C3N4sbnd Cu2O heterojunction exhibits the enhanced photocatalytic performance and high stability. It is revealed that the addition of PEG can promote the heterojunction effect of g-C3N4sbnd Cu2O, effectively improving the crystallinity and specific surface area of the photocatalyst, separation efficiency of photocarriers, and light absorption, thus enhancing the photocatalytic performance.

  15. Gene-environment interactions in multiple sclerosis: innate and adaptive immune responses to human endogenous retrovirus and herpesvirus antigens and the lectin complement activation pathway

    DEFF Research Database (Denmark)

    Christensen, Tove; Petersen, Thor; Thiel, Steffen

    2006-01-01

    -associated molecular pattern recognition: mannan-binding lectin (MBL), and MASP-2 and MASP-3. For representative MS families, we also determined herpesvirus serology for HSV-1, VZV, and EBV; and tissue typed for HLA-B, and HLA DR and DQ. In MS, a significant correlation between elevated immune reactivity to HERV-H Env...

  16. Gene-environment interactions in multiple sclerosis: Innate and adaptive immune responses to human endogenous retrovirus and herpesvirus antigens and the lectin complement activation pathway

    DEFF Research Database (Denmark)

    Christensen, Tove; Petersen, Thor; Thiel, Steffen

    2007-01-01

    -associated molecular pattern recognition: mannan-binding lectin (MBL), and MASP-2 and MASP-3. For representative MS families, we also determined herpesvirus serology for HSV-1, VZV, and EBV; and tissue typed for HLA-B, and HLA DR and DQ. In MS, a significant correlation between elevated immune reactivity to HERV-H Env...

  17. The lectin pathway of complement

    DEFF Research Database (Denmark)

    Ballegaard, Vibe Cecilie Diederich; Haugaard, Anna Karen; Garred, P

    2014-01-01

    The pattern recognition molecules of the lectin complement pathway are important components of the innate immune system with known functions in host-virus interactions. This paper summarizes current knowledge of how these intriguing molecules, including mannose-binding lectin (MBL), Ficolin-1, -2......-1, -2 and -3 and CL-11 could have similar functions in HIV infection as the ficolins have been shown to play a role in other viral infections, and CL-11 resembles MBL and the ficolins in structure and binding capacity.......The pattern recognition molecules of the lectin complement pathway are important components of the innate immune system with known functions in host-virus interactions. This paper summarizes current knowledge of how these intriguing molecules, including mannose-binding lectin (MBL), Ficolin-1, -2...

  18. One-pot, self-assembled hydrothermal synthesis of 3D flower-like CuS/g-C3N4 composite with enhanced photocatalytic activity under visible-light irradiation

    Science.gov (United States)

    Khan, Azam; Alam, Umair; Raza, Waseem; Bahnemann, D.; Muneer, M.

    2018-04-01

    Novel visible-light-driven 3D flower-like CuS/g-C3N4 composites have been synthesized by different wt% of CuS using hydrothermal method and characterized by standard analytical techniques such as XRD, FTIR, XPS, BET, UV-Vis DRS spectroscopy, SEM-EDS, and TEM. SEM and TEM analyses showed an intimate interfacial contact between flower-like CuS and g-C3N4 sheet. The synthesized composite materials (CuS/g-C3N4) showed excellent photocatalytic activity for the decolorization of methylene blue (MB) in aqueous suspension under visible-light irradiation, compared with pure CuS and g-C3N4. Among various composites of CuS/g-C3N4, 10 wt% of CuS showed highest photocatalytic activity for the decolorization of dye (MB). This remarkably improved photocatalytic performance of the synthesized materials could be attributed to the synergistic interaction between CuS and g-C3N4, leading to prolonged lifetime of photo-generated e- and h+ pair through the Z-scheme system. A probable Z-scheme mechanism explaining the origin of enhanced performance of the composite material has been proposed. This work not only provides a facile way to synthesize 3D flower-like heterostructure, but also renders rational design for the development of highly efficient Z-scheme photocatalytic systems.

  19. Detection, purification and characterization of a lectin from freshwater green algae Spirogyra spp.

    Directory of Open Access Journals (Sweden)

    ANTÔNIA S. DE OLIVEIRA

    2017-08-01

    Full Text Available ABSTRACT Freshwater algae are rich sources of structurally biologically active metabolites, such as fatty acids, steroids, carotenoids and polysaccharides. Among these metabolites, lectins stand out. Lectins are proteins or glycoproteins of non-immune origin which bind to carbohydrates or glycoconjugates, without changing ligand structure. Many studies have reported on the use of Spirogyra spp. as effective bioindicators of heavy metals; however, reports on Spirogyra molecular bioprospecting are quite limited. Therefore, this study aimed to detect, isolate, purify and characterize a lectin present in the freshwater green algae Spirogyra. Presence of the lectin protein in the extract was detected by hemagglutination assays. Subsequently, the protein extract was subjected to a sugar inhibition assay to identify the lectin-specific carbohydrate. Following this, the extract was applied to a guar gum column to afford the pure lectin. The lectin was inhibited by N-acetyl-glucosamine and N-acetyl-beta-D-mannose, but more strongly by D-galactose. The apparent molecular mass of the purified lectin was evaluated by Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE. Electrophoretic analysis revealed a single protein band with an apparent molecular mass of 56 kDa. Thus, it could be concluded that a lectin was purified from Spirogyra spp.

  20. Studies on lectins. XXXII. Application of affinity electrophoresis to the study of the interaction of lectins and their derivatives with sugars.

    Science.gov (United States)

    Horejsí, V; Tichá, M; Kocourek, J

    1977-09-29

    Affinity electrophoresis was used to study the sugar binding heterogeneity of lectins or their derivatives. Commercial and demetallized preparations of concanavalin A could be resolved by affinity electrophoresis into three components with different affinity to immobilized sugar. Similarly the Vicia cracca lectin obtained by affinity chromatography behaved on affinity gels as a mixture of active and inactive molecular species. Affinity electrophoresis has shown that the nonhemagglutinating acetylated lentil lectin and photo-oxidized or sulfenylated pea lectin retain their sugar binding properties; dissociation constants of saccharide complexes of these derivatives are similar to those of native lectins. The presence of specific immobilized sugar in the affinity gel improved the resolution of isolectins from Dolichos biflorus and Ricinus communis seeds.

  1. Inhibitors of HIV-1 maturation: Development of structure-activity relationship for C-28 amides based on C-3 benzoic acid-modified triterpenoids.

    Science.gov (United States)

    Swidorski, Jacob J; Liu, Zheng; Sit, Sing-Yuen; Chen, Jie; Chen, Yan; Sin, Ny; Venables, Brian L; Parker, Dawn D; Nowicka-Sans, Beata; Terry, Brian J; Protack, Tricia; Rahematpura, Sandhya; Hanumegowda, Umesh; Jenkins, Susan; Krystal, Mark; Dicker, Ira B; Meanwell, Nicholas A; Regueiro-Ren, Alicia

    2016-04-15

    We have recently reported on the discovery of a C-3 benzoic acid (1) as a suitable replacement for the dimethyl succinate side chain of bevirimat (2), an HIV-1 maturation inhibitor that reached Phase II clinical trials before being discontinued. Recent SAR studies aimed at improving the antiviral properties of 2 have shown that the benzoic acid moiety conferred topographical constraint to the pharmacophore and was associated with a lower shift in potency in the presence of human serum albumin. In this manuscript, we describe efforts to improve the polymorphic coverage of the C-3 benzoic acid chemotype through modifications at the C-28 position of the triterpenoid core. The dimethylaminoethyl amides 17 and 23 delivered improved potency toward bevirimat-resistant viruses while increasing C24 in rat oral PK studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. In situ synthesis of g-C3N4/TiO2 heterojunction nanocomposites as a highly active photocatalyst for the degradation of Orange II under visible light irradiation.

    Science.gov (United States)

    Ren, Bin; Wang, Tiecheng; Qu, Guangzhou; Deng, Fang; Liang, Dongli; Yang, Wenli; Liu, Meishan

    2018-05-04

    As a highly active photocatalyst, g-C 3 N 4 /TiO 2 heterojunction nanocomposites were in situ synthesized by simple ultrasonic mixing and calcination by using TiO 2 and melamine as precursors. The morphology and structure of the prepared photocatalysts were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activities of g-C 3 N 4 /TiO 2 nanocomposites to degrade Orange II (AO7) under visible light irradiation were evaluated. Results showed that the photocatalytic rate of the prepared g-C 3 N 4 /TiO 2 photocatalyst to degrade AO7 was about three times than that of pristine TiO 2 and g-C 3 N 4 . The g-C 3 N 4 /TiO 2 composite with a ratio of 1:4 had the highest degradation efficiency for AO7 solution. Its degradation efficiency under acidic conditions was significantly higher than that under alkaline conditions. The enhancement of photocatalytic activity can be attributed to the formation of heterojunctions between g-C 3 N 4 and TiO 2 , which leads to rapid charge transfer and the efficient separation of photogenerated electron-hole pairs. The recycling experiment indicated that the photocatalyst of g-C 3 N 4 /TiO 2 nanocomposites still maintained good photochemical stability and recyclability after five cycles; this finding was important for its practical applications. A series of free radical trapping experiments showed that •O 2 - played a crucial role in the degradation of AO7. Graphical Abstract ᅟ.

  3. The Lectin Complement Pathway in Patients with Necrotizing Soft Tissue Infection

    DEFF Research Database (Denmark)

    Hansen, Marco Bo; Rasmussen, Lars S; Pilely, Katrine

    2016-01-01

    BACKGROUND: Mannose-binding lectin (MBL) and ficolins are pattern recognition molecules (PRMs) that play an important role during infection through activation of the lectin complement pathway. We assessed whether plasma PRM levels were associated with mortality in patients with necrotizing soft t...

  4. Human mannose-binding lectin inhibitor prevents Shiga toxin-induced renal injury

    DEFF Research Database (Denmark)

    Ozaki, Masayuki; Kang, Yulin; Tan, Ying Siow

    2016-01-01

    Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC HUS) is a worldwide endemic problem, and its pathophysiology is not fully elucidated. Here we tested whether the mannose-binding lectin (MBL2), an initiating factor of lectin complement pathway activation, plays a cr...

  5. A facile one-pot preparation of Co3O4/g-C3N4 heterojunctions with excellent electrocatalytic activity for the detection of environmental phenolic hormones

    Science.gov (United States)

    Sun, Yanjuan; Jiang, Jizhou; Liu, Yi; Wu, Shengli; Zou, Jing

    2018-02-01

    The Co3O4/g-C3N4 heterojunctions were prepared by a facile one-pot thermal decomposition technique. Compared with g-C3N4, it was found that Co3O4/g-C3N4 heterojunctions possessed a higher Brunner-Emmet-Teller (BET) surface area, which was beneficial to the diffusion of aim molecules on the electrode surfaces. And the optimal Co3O4/g-C3N4 heterojunctions exhibited a narrower band gap and a higher donor density, resulting in an excellent electrocatalytic activity for environmental phenolic hormones. Moreover, the Co3O4/g-C3N4 heterojunctions were used for the electrochemical sensing of environmental phenolic hormones such as bisphenol A, pentachlorophenol, p-nitrophenol and octylphenol. All detection ranges reached three orders of magnitude, showing a lower limit of detection of 10-9 mol L-1. So, sensitivity and accurate determination of environmental phenolic hormones in real water samples may use this Co3O4/g-C3N4 heterojunctions modified electrode.

  6. Probing the cons and pros of lectin-induced immunomodulation: case studies for the mistletoe lectin and galectin-1.

    Science.gov (United States)

    Gabius, H J

    2001-07-01

    When imagining to monitor animal cells through a microscope with resolution at the molecular level, a salient attribute of their surfaces will be the abundance of glycan chains. They present galactosides at their termini widely extending like tentacles into the extracellular space. Their spatial accessibility and their potential for structural variability endow especially these glycan parts with capacity to act as docking points for molecular sensors (sugar receptors such as lectins). Binding and ligand clustering account for transmission of post-binding signals into the cell interior. The range of triggered activities has turned plant lectins into popular tools in cell biology and immunology. Potential for clinical application has been investigated rigorously only in recent years. As documented in vitro and in vivo for the galactoside-specific mistletoe lectin, its apparent immunomodulatory capacity reflected in upregulation of production of proinflammatory cytokines will not necessarily be clinically favorable but a double-edged sword. In fact, lectin application has been shown to stimulate tumor growth in cell lines, histocultures of human tumors and in two animal models using chemical carcinogenesis or tumor transplantation. When testing immunological effects of the endogenous lectin galectin-1, protection against disorders mediated by activated T cells came up for consideration. Elimination of these cells via CD7-dependent induction of apoptosis, and a shift to the Th2 response by the galectin, are factors to ameliorate disease states. This result encourages further efforts with other galectins. Functional redundancy, synergism, diversity or antagonism among galectins are being explored to understand the actual role of this class of endogenous lectins in inflammation. Regardless of the results of further preclinical testing for galectin-1, these two case studies break new ground in our understanding how glycans as ligands for lectins convey reactivity to

  7. Low-temperature solid-state preparation of ternary CdS/g-C_3N_4/CuS nanocomposites for enhanced visible-light photocatalytic H_2-production activity

    International Nuclear Information System (INIS)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Highlights: • CdS/g-C_3N_4/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C_3N_4/CuS show enhanced visible-light photocatalytic H_2 evolution activity. • The enhanced photocatalytic H_2 production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C_3N_4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C_3N_4/CuS composite exhibits a high visible-light photocatalytic H_2-production rate of 57.56 μmol h"−"1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na_2S/Na_2SO_3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C_3N_4/CuS composites show the enhanced visible-light photocatalytic H_2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C_3N_4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H_2-production activity.

  8. Preparation of Ulex europaeus lectin-gliadin nanoparticle conjugates and their interaction with gastrointestinal mucus.

    Science.gov (United States)

    Ezpeleta, I; Arangoa, M A; Irache, J M; Stainmesse, S; Chabenat, C; Popineau, Y; Orecchioni, A M

    1999-11-25

    One approach to improve the bioavailability and efficiency of drugs consists of the association of a ligand (i.e. lectins), showing affinity for biological structures located on the mucosa surfaces, to nanoparticulate drug delivery systems. In this context, Ulex europaeus lectin-gliadin nanoparticle conjugates (UE-GNP) were prepared with the aim of evaluating their in vitro bioadhesive properties. The lectin was fixed by a covalent procedure to gliadin nanoparticles by a two-stage carbodiimide method. Typically, the amount of bound lectin was calculated to be approximately 15 microg lectin/mg nanoparticle, which represented a coupling efficiency of approximately 16% of the initial lectin concentration. In addition, the activity of these conjugates was tested with bovine submaxillary gland mucin (BSM) and the level of binding to this mucin was always much greater with UE-GNP than with controls (gliadin nanoparticles). However, the presence of 50 micromol fucose, which is the reported specific sugar for U. europaeus lectin, specifically inhibited the activity of these conjugates and, therefore, the UE-GNP binding to BSM was attenuated by 70%. These results clearly showed that the activity and specificity of U. europaeus lectin was preserved after covalent coupling to these biodegradable carriers.

  9. Bauhinia variegata var. variegata lectin: isolation, characterization, and comparison.

    Science.gov (United States)

    Chan, Yau Sang; Ng, Tzi Bun

    2015-01-01

    Bauhinia variegata var. variegata seeds are rich in proteins. Previously, one of the major storage proteins of the seeds was found to be a trypsin inhibitor that possessed various biological activities. By using another purification protocol, a glucoside- and galactoside-binding lectin that demonstrated some differences from the previously reported B. variegata lectin could be isolated from the seeds. It involved affinity chromatography on Affi-gel blue gel, ion exchange chromatography on Q-Sepharose and Mono Q, and also size exclusion chromatography on Superdex 75. The lectin was not retained on Affi-gel blue gel but interacted with Q-Sepharose. The lectin was a 64-kDa protein with two 32-kDa subunits. It had low thermostability (stable up to 50 °C) and moderate pH stability (stable in pH 3-10). It exhibited anti-proliferative activity on nasopharyngeal carcinoma HONE1 cells with an IC50 of 12.8 μM after treatment for 48 h. It also slightly inhibited the growth of hepatoma HepG2 cells. The lectin may have potential in aiding cancer treatments.

  10. Interleukin 2 secretion by lectin-activated human blood lymphocytes is markedly augmented by vascular endothelial cells

    International Nuclear Information System (INIS)

    Guinan, E.C.; Pober, J.S.

    1986-01-01

    Since the initial interaction (and possible activation) of a blood borne T lymphocyte involves contact with the endothelial lining of the vasculature at the site of an immune response, the authors have examined the effect of cultured human endothelial cells (HEC) upon polyclonal T cell activation. Addition of 10 4 HEC to 10 4 -10 5 peripheral blood lymphocytes (PBL) stimulated with phytohemagglutinin (PHA, 0.3-10 μg/ml) leads to marked augmentation of interleukin 2 (IL-2) production. The relative increase in IL-2 (mean of 3 expts. +/- SEM) is present at 24 h (5.8 fold +/- 1.5) and become more marked at 48 h (12.6 fold +/- 3.5) and 72 h (18.5 fold +/- 3.7). This relative enhancement is greater for HEC added to 10 4 than 10 5 PBL and is also greater when 10 4 rather than 2 x 10 3 HEC are added to a given number of PBL. This increased IL-2 concentration has two biological consequences. First, at suboptimal PHA doses or at low PBL number, PBL proliferation as measured by 3 H-thymidine incorporation is increased up to two fold. Second, the phenotype of the proliferating cells appears altered, including a decrease in mean density of IL-2 receptor. The authors hypothesize that such modulation of the concentration of locally produced IL-2 may play a key role in the nature of an immune response, influencing both its magnitude and the functional profile of the activated and amplified effector cells

  11. Preparation and enhanced photocatalytic activity of carbon nitride/titania(001 vs 101 facets)/reduced graphene oxide (g-C3N4/TiO2/rGO) hybrids under visible light

    Science.gov (United States)

    Huang, Meina; Yu, Jianhua; Hu, Qun; Su, Wenli; Fan, Minguang; Li, Bin; Dong, Lihui

    2016-12-01

    Herein, a novel photocatalyst, anatase TiO2 nanoparticles with both exposed (101) and (001) facets synchronously incorporated with g-C3N4 and graphene, was successfully prepared via a simple one-step solvothermal route. The morphology and structure of as-prepared composites were confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Efficiency of the prepared samples was investigated by monitoring the degradation of Methyl Orange (MO), Rhodamine B (RhB) and phenol under visible light irradiation. Improved photocatalytic activity in g-C3N4/TiO2/rGO is observed owing to higher specific surface area and enhanced visible light absorption capability. Most importantly, the in situ g-C3N4 and rGO doping might enhance the interaction among g-C3N4, TiO2 (001 vs 101) and rGO, which generates more synergistic heteroconjunctions in g-C3N4/TiO2/rGO facilitating a fast electron transfer at the interface among them. This synergistic approach could prove useful for the design and development of other visible light active photocatalysts with high chemical stability.

  12. Structure predictions of two Bauhinia variegata lectins reveal patterns of C-terminal properties in single chain legume lectins.

    Science.gov (United States)

    Moreira, Gustavo M S G; Conceição, Fabricio R; McBride, Alan J A; Pinto, Luciano da S

    2013-01-01

    Bauhinia variegata lectins (BVL-I and BVL-II) are single chain lectins isolated from the plant Bauhinia variegata. Single chain lectins undergo post-translational processing on its N-terminal and C-terminal regions, which determines their physiological targeting, carbohydrate binding activity and pattern of quaternary association. These two lectins are isoforms, BVL-I being highly glycosylated, and thus far, it has not been possible to determine their structures. The present study used prediction and validation algorithms to elucidate the likely structures of BVL-I and -II. The program Bhageerath-H was chosen from among three different structure prediction programs due to its better overall reliability. In order to predict the C-terminal region cleavage sites, other lectins known to have this modification were analysed and three rules were created: (1) the first amino acid of the excised peptide is small or hydrophobic; (2) the cleavage occurs after an acid, polar, or hydrophobic residue, but not after a basic one; and (3) the cleavage spot is located 5-8 residues after a conserved Leu amino acid. These rules predicted that BVL-I and -II would have fifteen C-terminal residues cleaved, and this was confirmed experimentally by Edman degradation sequencing of BVL-I. Furthermore, the C-terminal analyses predicted that only BVL-II underwent α-helical folding in this region, similar to that seen in SBA and DBL. Conversely, BVL-I and -II contained four conserved regions of a GS-I association, providing evidence of a previously undescribed X4+unusual oligomerisation between the truncated BVL-I and the intact BVL-II. This is the first report on the structural analysis of lectins from Bauhinia spp. and therefore is important for the characterisation C-terminal cleavage and patterns of quaternary association of single chain lectins.

  13. Studies on murine plasmocytoma treatment with mistletoe lectin I

    International Nuclear Information System (INIS)

    Raabe, F.; Storch, H.

    1987-01-01

    Mistletoe lectin I was tested in vivo and in vitro for its cytotoxic activity against murine plasmacytoma cells P3/X63-Ag8. As a result of this treatment, 30 to 60% of the BALB/c mice developed complete tumor regressions. 83% of the mice treated with mistletoe lectin I were resistant to viable tumor cell challenge after 100 days. The cytotoxic activity in vitro tested by 3 H-thymidine incorporation into P3/X63-Ag8 cells was very high. The rate was markedly reduced at concentrations up to 0.07 ng/ml. (author)

  14. Lectins and their application to clinical microbiology.

    OpenAIRE

    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 typ...

  15. Chronic low-dose UVA irradiation induces local suppression of contact hypersensitivity, Langerhans cell depletion and suppressor cell activation in C3H/HeJ mice

    International Nuclear Information System (INIS)

    Bestak, Rosa; Halliday, G.M.

    1996-01-01

    It has previously been demonstrated that chronic low-dose solar-simulated UV radiation could induce both local and systemic immunosuppression as well as tolerance to a topically applied hapten. In this study, we have used a chronic low-dose UV-irradiation protocol to investigate the effects of UVA on the skin immune system of C3H/HeJ mice. Irradiation with UVA+B significantly suppressed the local and systemic primary contact hypersensitivity (CHS) response to the hapten 2,4,6-trinitrochlorobenzene. Furthermore, UVA+B reduced Langerhans cell (LC) and dendritic epidermal T cell (DETC) densities in chronically UV-irradiated mice. Ultraviolet A irradiation induced local, but not systemic, immunosuppression and reduced LC (32%) but not DETC from the epidermis compared to the shaved control animals. Treatment of mice with both UVA+B and UVA radiation also induced an impaired secondary CHS response, and this tolerance was transferable with spleen cells. (Author)

  16. Purification of a thermostable antinociceptive lectin isolated from Andira anthelmia.

    Science.gov (United States)

    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. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Low-temperature solid-state preparation of ternary CdS/g-C3N4/CuS nanocomposites for enhanced visible-light photocatalytic H2-production activity

    Science.gov (United States)

    Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

    2017-01-01

    Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C3N4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C3N4/CuS composite exhibits a high visible-light photocatalytic H2-production rate of 57.56 μmol h-1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na2S/Na2SO3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C3N4/CuS composites show the enhanced visible-light photocatalytic H2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C3N4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H2-production activity.

  18. C-Type Lectin-Like Receptor 2 Suppresses AKT Signaling and Invasive Activities of Gastric Cancer Cells by Blocking Expression of Phosphoinositide 3-Kinase Subunits.

    Science.gov (United States)

    Wang, Lan; Yin, Jie; Wang, Xuefei; Shao, Miaomiao; Duan, Fangfang; Wu, Weicheng; Peng, Peike; Jin, Jing; Tang, Yue; Ruan, Yuanyuan; Sun, Yihong; Gu, Jianxin

    2016-05-01

    C-type lectin-like receptor 2 (CLEC2) is a transmembrane receptor expressed on platelets and several hematopoietic cells. CLEC2 regulates platelet aggregation and the immune response. We investigated its expression and function in normal and transformed gastric epithelial cells from human tissues. We performed tissue microarray analyses of gastric carcinoma samples collected from 96 patients who underwent surgery at Zhongshan Hospital of Fudan University in Shanghai, China and performed real-time polymerase chain reaction assays from an independent group of 60 patients; matched nontumor gastric mucosa tissues were used as the control. Full-length and mutant forms of CLEC2 were expressed in gastric cancer cell line (MGC80-3), or CLEC2 protein was knocked down using small-hairpin RNAs in gastric cancer cell lines (NCI-N87 and AGS). CLEC2 signaling was stimulated by incubation of cells with recombinant human podoplanin or an antibody agonist of CLEC2; cell migration and invasion were assessed by transwell and wound-healing assays. Immunoblot, immunofluorescence microscopy, and real-time polymerase chain reaction assays were used to measure expression of markers of the epithelial to mesenchymal transition and activation of signaling pathways. Immunoprecipitation experiments were performed with an antibody against spleen tyrosine kinase (SYK). Cells were injected into lateral tail vein of BALB/C nude mice; some mice were also given injections of the phosphoinositide 3-kinase (PI3K) inhibitor LY294002. Lung and liver tissues were collected and analyzed for metastases. Levels of CLEC2 were higher in nontumor gastric mucosa (control) than in gastric tumor samples. Levels of CLEC2 protein in gastric tumor tissues correlated with depth of tumor invasion, metastasis to lymph node, tumor TNM stage, and 5-year survival of patients. Activation of CLEC2 in gastric cancer cells reduced their invasive activities in vitro and expression of epithelial to mesenchymal transition

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

    Energy Technology Data Exchange (ETDEWEB)

    Matsuno, Keita; Nakayama, Eri; Noyori, Osamu [Department of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo (Japan); Marzi, Andrea; Ebihara, Hideki [Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT (United States); Irimura, Tatsuro [Graduate School of Pharmaceutical Science, University of Tokyo, Tokyo (Japan); Feldmann, Heinz [Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT (United States); Takada, Ayato, E-mail: atakada@czc.hokudai.ac.jp [Department of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo (Japan)

    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.

  20. Purification and characterization of liver lectins from a lizard, Sceloporus spinosus.

    Science.gov (United States)

    Fenton, N Bertha; Arreguín, L Barbarin; Méndez, C Fausto; Arreguín, E Roberto

    2004-05-01

    This study discusses the purification of soluble beta-galactose lectins obtained from the lizard liver of Sceloporus spinosus. The first lectin named lizard hepatic lectin-1 (LHL-1) presented a molecular weight of 31,750, with an isoelectric point of 4.25. The highest specific hemagglutinating activity was achieved using human blood type A1: N-acetylgalactosamine (GalNAc)-galactose (Gal)-fucose (Fuc). Carbohydrate inhibition assays indicated a higher lectin specificity for GalNAc. For LHL-2 the molecular weight obtained was 23,850 with an isoelectric point of 3.25. The highest carbohydrate specificity was observed for Gal. These lizard hepatic lectins are similar to the mammal hepatic lectins previously reported. However, it is different from the alligator hepatic lectin (AHL). The homology analyses of LHL-1 resulted in 100% identity with the Steroidogenic acute regulatory protein (StAR), while LHL-2 was similar to adenylate kinase (75% identity). We suggest that these liver lectins are related to the inherent functions of liver previously reported.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    Research highlights: → Filovirus glycoprotein (GP) having a deficient receptor binding region were generated. → Mutant GPs mediated virus entry less efficiently than wild-type GP. → Mutant GPs bound to C-type lectins but not mediated entire steps of cellular entry. → C-type lectins do not independently mediate filovirus entry into cells. → 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.

  2. Isolation and Biochemical Characterization of Apios Tuber Lectin

    Directory of Open Access Journals (Sweden)

    Eri Kenmochi

    2015-01-01

    Full Text Available 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.

  3. Mannan-binding lectin and mannan-binding lectin-associated serine protease 2 in acute pancreatitis

    DEFF Research Database (Denmark)

    Novovic, Srdan; Andersen, Anders; Ersbøll, Annette Kjær

    2011-01-01

    Complement activation may play a prominent role in acute pancreatitis (AP). Mannan-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) participate in complement activation. The objective of the present study was to evaluate the role of MBL and MASP-2 as markers in AP with regard...

  4. Generation of a C3c specific monoclonal antibody and assessment of C3c as a putative inflammatory marker derived from complement factor C3

    DEFF Research Database (Denmark)

    Palarasah, Yaseelan; Skjodt, Karsten; Brandt, Jette

    2010-01-01

    complex (C5b-C9) and quantification of complement split products by precipitation-in-gel techniques (e.g. C3d). We have developed a mouse monoclonal antibody (mAb) that is able to detect fluid phase C3c without interference from other products generated from the complement component C3. The C3c specific m....... The C3c mAb was confirmed to be C3c specific, as it showed no cross-reactivity with native (un-cleaved) C3, with C3b, iC3b, or with C3d. Also, no significant reaction was observed with C3 fragments in factor I deficient sera or plasma. This antibody forms the basis for the generation of a robust ELISA...... that allows for a quick and reliable evaluation of complement activation and consumption as a marker for inflammatory processes. We established the C3c plasma range in 100 healthy Danish blood donors with a mean of 3.47 μg/ml and a range of 2.12-4.92 μg/ml. We believe that such an antibody might...

  5. Biological role of lectins: A review

    Directory of Open Access Journals (Sweden)

    K Kiran Kumar

    2012-01-01

    Full Text Available Lectins comprise a stracturally vary diverse class of proteins charecterized by their ability to selectively bind carbohydrate moieties of the glycoproteins of the cell surface. Lectins may be derived from plants, microbial or animal sources and may be soluble or membrane bound. Lectins is a tetramer made up of four nearly identical subunits. In human, lectins have been reported to cause food poisoning, hemolytic anemia, jaundice, digestive distress, protein and carbohydrate malabsorption and type I allergies. The present review focuses on the classification, structures, biological significance and application of lectins.

  6. In vitro antitumour activity, safety testing and subcellular distribution of two poly[oxyethylene(aminophosphonate-co-H-phosphonate]s in Ehrlich ascites carcinoma and BALB/c 3T3 cell culture systems

    Directory of Open Access Journals (Sweden)

    Ani Georgieva

    2016-01-01

    Full Text Available Two polyphosphoesters containing anthracene-derived aminophosphonate and hydrophilic H-phosphonate repeating units, poly[oxyethylene(aminophosphonate-co-H-phosphonate]s (1 and 2, were tested for the in vitro antitumour activity on cell cultures derived from ascitic form of Ehrlich mammary adenocarcinoma by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT-dye reduction assay. The in vitro safety testing of the copolymers was performed by BALB/c 3T3 neutral red uptake assay. A study on their uptake and subcellular distribution in non-tumourigenic and tumour cells was performed by means of fluorescence microscopy. Both copolymers showed significant antitumour activity towards Ehrlich ascites carcinoma (EAC cells. However, the in vitro safety testing revealed significant toxicity of polymer 2 to BALB/c 3T3 mouse embryo cells. In contrast, polymer 1 showed complete absence of cytotoxicity to BALB/c 3T3 cells. The fluorescent studies showed that the substances were diffusely distributed in the cytoplasm in both cell culture systems. As opposed to BALB/c 3T3 cells, in EAC cells, intense fluorescent signal was observed in the nuclei and in the perinuclear region. The tested polyphosphoesters are expected to act under physiological conditions as prodrugs of aminophosphonates.

  7. [Separation of osteoclasts by lectin affinity chromatography].

    Science.gov (United States)

    Itokazu, M; Tan, A; Tanaka, S

    1991-09-01

    Newborn rat calvaria bone cells obtained by digestion were fractionated on columns of wheat-germ agglutinin (WGA) sepharose 6MB for osteoclast isolation. The initial nonspecific binding cells which were passed through the WGA sepharose column by a buffer acquired a high enzyme activity of alkaline phosphatase, but not that of acid phosphatase. However, elution of cells using a buffer with the addition of N-acetyl-D-glucosamine resulted in a high acid phosphatase activity but no alkaline phosphatase activity. The former WGA binding negative fraction enriched osteoblasts averaging 30 microns in size. The latter WGA binding positive fraction enriched osteoclasts ranging from 20 microns to 60 microns in size. The electron-microscope clearly demonstrated the cellular details of osteoclasts. Isolated cell counts showed a ratio of six to four. These results indicate that our method of osteoclast isolation is simple and useful in lectin affinity chromatography because all cells have sugar moieties on their surface and the binding of osteoclasts can be reversed by the addition of specific lectin-binding sugars to the eluting buffer.

  8. Effect of Lectins from Diocleinae Subtribe against Oral Streptococci

    Directory of Open Access Journals (Sweden)

    Edson Holanda Teixeira

    2011-04-01

    Full Text Available 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.

  9. Lectindb: a plant lectin database.

    Science.gov (United States)

    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.

  10. Lectin complement pathway gene profile of the donor and recipient does not influence graft outcome after kidney transplantation.

    NARCIS (Netherlands)

    Damman, J.; Kok, J.L.; Snieder, H.; Leuvenink, H.G.; Goor, H. van; Hillebrands, J.L.; Dijk, M.C.R.F. van; Hepkema, B.G.; Reznichenko, A.; Born, J. van den; Borst, M.H. de; Bakker, S.J.; Navis, G.J.; Ploeg, R.J.; Seelen, M.A.

    2012-01-01

    In kidney transplantation, complement activation was found to be induced by donor brain death, renal ischemia-reperfusion injury and allograft rejection. There are three known pathways of complement activation: the classical, lectin and the alternative pathway. The lectin complement pathway can be

  11. Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation

    Science.gov (United States)

    Petrova, Mariya I.; Imholz, Nicole C. E.; Verhoeven, Tine L. A.; Balzarini, Jan; Van Damme, Els J. M.; Schols, Dominique; Vanderleyden, Jos; Lebeer, Sarah

    2016-01-01

    Objectives Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties. Methods The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening. Results The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells. Conclusions Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections. PMID:27537843

  12. Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation.

    Science.gov (United States)

    Petrova, Mariya I; Imholz, Nicole C E; Verhoeven, Tine L A; Balzarini, Jan; Van Damme, Els J M; Schols, Dominique; Vanderleyden, Jos; Lebeer, Sarah

    2016-01-01

    Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties. The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening. The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells. Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections.

  13. Association of Low Ficolin-Lectin Pathway Parameters with Cardiac Syndrome X

    DEFF Research Database (Denmark)

    Horváth, Z; Csuka, Dorottya; Vargova, K

    2016-01-01

    In patients with typical angina pectoris, inducible myocardial ischaemia and macroscopically normal coronaries (cardiac syndrome X (CSX)), a significantly elevated plasma level of terminal complement complex (TCC), the common end product of complement activation, has been observed without.......003). In conclusion, in patients with typical angina and myocardial ischaemia despite macroscopically normal coronary arteries, low levels of several lectin pathway parameters were observed, indicating complement activation and consumption. Complement activation through the ficolin-lectin pathway might play a role...

  14. P17, an Original Host Defense Peptide from Ant Venom, Promotes Antifungal Activities of Macrophages through the Induction of C-Type Lectin Receptors Dependent on LTB4-Mediated PPARγ Activation

    Directory of Open Access Journals (Sweden)

    Khaddouj Benmoussa

    2017-11-01

    Full Text Available Despite the growing knowledge with regard to the immunomodulatory properties of host defense peptides, their impact on macrophage differentiation and on its associated microbicidal functions is still poorly understood. Here, we demonstrated that the P17, a new cationic antimicrobial peptide from ant venom, induces an alternative phenotype of human monocyte-derived macrophages (h-MDMs. This phenotype is characterized by a C-type lectin receptors (CLRs signature composed of mannose receptor (MR and Dectin-1 expression. Concomitantly, this activation is associated to an inflammatory profile characterized by reactive oxygen species (ROS, interleukin (IL-1β, and TNF-α release. P17-activated h-MDMs exhibit an improved capacity to recognize and to engulf Candida albicans through the overexpression both of MR and Dectin-1. This upregulation requires arachidonic acid (AA mobilization and the activation of peroxisome proliferator-activated receptor gamma (PPARγ nuclear receptor through the leukotriene B4 (LTB4 production. AA/LTB4/PPARγ/Dectin-1-MR signaling pathway is crucial for P17-mediated anti-fungal activity of h-MDMs, as indicated by the fact that the activation of this axis by P17 triggered ROS production and inflammasome-dependent IL-1β release. Moreover, we showed that the increased anti-fungal immune response of h-MDMs by P17 was dependent on intracellular calcium mobilization triggered by the interaction of P17 with pertussis toxin-sensitive G-protein-coupled receptors on h-MDMs. Finally, we also demonstrated that P17-treated mice infected with C. albicans develop less severe gastrointestinal infection related to a higher efficiency of their macrophages to engulf Candida, to produce ROS and IL-1β and to kill the yeasts. Altogether, these results identify P17 as an original activator of the fungicidal response of macrophages that acts upstream PPARγ/CLRs axis and offer new immunomodulatory therapeutic perspectives in the field of

  15. Lectin cDNA and transgenic plants derived therefrom

    Science.gov (United States)

    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.

  16. A sperm-agglutinating lectin from seeds of Jack fruit (Artocarpus heterophyllus).

    Science.gov (United States)

    Namjuntra, P; Muanwongyathi, P; Chulavatnatol, M

    1985-04-30

    A lectin specific for N-acetylgalactosamine was isolated from seed extract of Jack fruit (Artocarpus heterophyllus) by ammonium sulfate precipitation, followed by affinity chromatography on a Affigel-galactosamine-agarose column. The lectin possessed agglutinating activities for human and rat sperm as well as human red blood cells. It was found to have Mr = 62,000 consisting of two dissimilar subunits of Mr = 18,000 and 13,000. It also cross-reacted with an antibody against the lectin of Osage Orange (Maclura pomifera).

  17. Immunologically related lectins from stems and roots of developing seedlings of Cucurbita ficifolia: purification and some properties of root and stem lectins

    Directory of Open Access Journals (Sweden)

    Irena Lorenc-Kubis

    2014-01-01

    Full Text Available Hemagglutinating activity has been found in acetate extracts from roots and stems of squash seedlings (Cucurbita ficifolia. The hemaglutinating activity changes during seeds germination and seedling development. Dot blot and Western blot techniques have shown that proteins from these vegetative tissues cross-reacted with antibodies raised against endogenous cotyledons lectin CLBa and Con A.Lectins were isolated from stems and roots of 6-day old seedlings by precipitation with ethanol, affinity chromatography on Con A-Sepharose, gel filtration on Bio-gel P100 and separated by electrophoresis on polyacrylamide gel. Three purified lectins (RLA1, RLA2, RLA3 were obtained from roots and four from stems (SLA1, SLA2, SLA3, SLA4. The purified lectins from roots and stems agglutinated all human red blood cells, but sheep erythrocytes were most sensitive to agglutination. The hemagglutination of the root lectins RLA2 and RLA3 was inhibited by a very low concentration of arabinose, while RLA1, of xylose and Ga1NAc. Arabinose and Xylose were also found to be the most effective inhibitors of all stem lectins.

  18. Structure of Dioclea virgata lectin: relations between carbohydrate binding site and nitric oxide production

    International Nuclear Information System (INIS)

    Delatorre, P.; Gadelha, C.A.A.; Santi-Gadelha, T.; Nobrega, R.B.; Rocha, B.A.M.; Nascimento, K.S.; Naganao, C.S.; Sampaio, A.H.; Cavada, B.S.; Pires, A.F.; Assreuy, A.M.S.

    2012-01-01

    Full text: Lectins are proteins/glycoproteins with at least one noncatalytic domain binding reversibly to specific monosaccharides or oligosaccharides. By binding to carbohydrate moieties on the cell surface, lectins participate in a range of cellular processes without changing the properties of the carbohydrates involved. The lectin of Dioclea virgata (DvirL), both native and complexed with X-man, was submitted to X-ray diffraction analysis and the crystal structure was compared to that of other Diocleinae lectins in order to better understand differences in biological proper- ties, especially with regard to the ability of lectins to induce nitric oxide (NO) production. The DvirL diffraction analysis revealed that both the native crystal and the X-Man-complexed form are orthorhombic and belong to space group I222. The cell parameters were: a=65.4 , b=86.6 and c=90.2 (native structure), and a=61.89 , b=87.67 and c=88.78 (X-Man-complexed structure). An association was observed between the volume of the carbohydrate recognition domain (CRD), the ability to induce NO production and the relative positions of Tyr12, Arg228 and Leu99. Thus, differences in biological activity induced by Diocleinae lectins are related to the configuration of amino acid residues in the carbohydrate binding site and to the structural conformation of subsequent regions capable of influencing site-ligand interactions. In conclusion, the ability of Diocleinae lectins to induce NO production depends on CRD configuration. (author)

  19. Mannan-binding lectin is involved in the protection against renal ischemia/ reperfusion injury by dietary restriction

    NARCIS (Netherlands)

    Shushimita; P. van der Pol (Pieter); R.W.F. de Bruin (Ron); J.N.M. IJzermans (Jan); C. van Kooten (Cees); F.J.M.F. Dor (Frank)

    2015-01-01

    textabstractPreoperative fasting and dietary restriction offer robust protection against renal ischemia/ reperfusion injury (I/RI) in mice.We recently showed that Mannan-binding lectin (MBL), the initiator of the lectin pathway of complement activation, plays a pivotal role in renal I/RI. Based on

  20. Mannose-binding lectin (MBL2) and ficolin-2 (FCN2) polymorphisms in patients on peritoneal dialysis with staphylococcal peritonitis

    NARCIS (Netherlands)

    Meijvis, Sabine C. A.; Herpers, Bjorn L.; Endeman, Henrik; de Jong, Ben; van Hannen, Erik; van Velzen-Blad, Heleen; Krediet, Raymond T.; Struijk, Dirk G.; Biesma, Douwe H.; Bos, Willem Jan W.

    Background. Mannose-binding lectin (MBL) and ficolin-2 (FCN) are activators of the lectin pathway of complement and act as primary defences against infection. Single-nucleotide polymorphisms (SNPs) in the MBL2 and FCN2 genes influence the functionality of the proteins. Both proteins are capable of

  1. Protozoa lectins and their role in host-pathogen interactions.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Raphael Contelli Klein

    Full Text Available 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. Potassium ions intercalated into g-C3N4-modified TiO2 nanobelts for the enhancement of photocatalytic hydrogen evolution activity under visible-light irradiation

    Science.gov (United States)

    Ma, Jian; Zhou, Wei; Tan, Xin; Yu, Tao

    2018-05-01

    Solar-to-chemical energy conversion is a challenging photochemical reaction for renewable energy storage. In recent decades, photocatalytic H2 evolution has been studied extensively. TiO2 is a well-established semiconductor in the field of photocatalytic H2 production; however, its low efficiency for solar energy utilization, and high photocarrier recombination rate, restrict its photocatalytic efficiency. Here, a series of K-intercalated g-C3N4-modified TiO2 nanobelts (TCN–Kx) with different dosages of K atoms were fabricated using a hydrothermal method followed by a calcination process. XRD, TEM and XPS tests indicate that a tight interfacial connection is formed between K–g-C3N4 and the TiO2 nanobelts. DFT calculations indicated that K dopants prefer to be at the interlayer sites of g-C3N4, suggesting increased charge transfer efficiency. The H2 production efficiency of the TCN–Kx composite materials from water splitting under visible-light irradiation was clearly improved. Steady fluorescence spectroscopy and photocurrent measurements confirmed that the improvement in photocatalytic H2 production activity was due to the superior charge separation and electron transfer efficiency of TCN–Kx composite materials.

  5. Isolation and characterization of a novel lectin from the mushroom Armillaria luteo-virens

    International Nuclear Information System (INIS)

    Feng, K.; Liu, Q.H.; Ng, T.B.; Liu, H.Z.; Li, J.Q.; Chen, G.; Sheng, H.Y.; Xie, Z.L.; Wang, H.X.

    2006-01-01

    From the dried fruiting bodies of the mushroom Armillaria luteo-virens, a dimeric lectin with a molecular mass of 29.4 kDa has been isolated. The purification procedure involved (NH 4 ) 2 SO 4 precipitation, ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The hemagglutinating activity of the lectin could not be inhibited by simple sugars but was inhibited by the polysaccharide inulin. The activity was stable up to 70 o C but was acid- and alkali-labile. Salts including FeCl 3 , AlCl 3 , and ZnCl 2 inhibited the activity whereas MgCl 2 , MnCl 2 , and CaCl 2 did not. The lectin stimulated mitogenic response of mouse splenocytes with the maximal response achieved by 1 μM lectin. Proliferation of tumor cells including MBL2 cells, HeLa cells, and L1210 cells was inhibited by the lectin with an IC 5 of 2.5, 5, and 10 μM, respectively. However, proliferation of HepG2 cells was not affected. The novel aspects of the isolated lectin include a novel N-terminal sequence, fair thermostability, acid stability, and alkali stability, together with potent mitogenic activity toward spleen cells and antiproliferative activity toward tumor cells

  6. STUDY OF AZOSPIRILLUM LECTINS INFLUENCE ON HYDROGEN PEROXIDE PRODUCTION IN WHEAT-ROOTS

    Directory of Open Access Journals (Sweden)

    Alen’kina S.A.

    2009-12-01

    Full Text Available It was found that two cell-surface lectins isolated from the nitrogen-fixing soil bacterium Azospirillum brasilense Sp7 and from its mutant defective in lectin activity, A. brasilense Sp7.2.3 can stimulate rapid formation of hydrogen peroxide, associated with an increase in the activities of oxalate oxidase and peroxidase in the roots of wheat seedlings. The most advantageous and most rapidly induced pathway of hydrogen peroxide formation was the oxidation of oxalic acid by oxalate oxidase because in this case, a 10-min treatment of the roots with the lectins at 10 µg ml-1 was sufficient. The data from this study attest that the Azospirillum lectins can act as inducers of adaptation processes in the roots of wheat seedlings.

  7. Stability of Curcuma longa rhizome lectin: Role of N-linked glycosylation.

    Science.gov (United States)

    Biswas, Himadri; Chattopadhyaya, Rajagopal

    2016-04-01

    Curcuma longa rhizome lectin, a mannose-binding protein of non-seed portions of turmeric, is known to have antifungal, antibacterial and α-glucosidase inhibitory activities. We studied the role of complex-type glycans attached to asparagine (Asn) 66 and Asn 110 to elucidate the role of carbohydrates in lectin activity and stability. Apart from the native lectin, the characteristics of a deglycosylated Escherichia coli expressed lectin, high-mannose oligosaccharides at both asparagines and its glycosylation mutants N66Q and N110Q expressed in Pichia pastoris, were compared to understand the relationship between glycosylation and activity. Far UV circular dichroism (CD) spectra, fluorescence emission maximum, hemagglutination assay show no change in secondary or tertiary structures or sugar-binding properties between wild-type and aforementioned recombinant lectins under physiological pH. But reduced agglutination activity and loss of tertiary structure are observed in the acidic pH range for the deglycosylated and the N110Q protein. In thermal and guanidine hydrochloride (GdnCl)-induced unfolding, the wild-type and high-mannose lectins possess higher stability compared with the deglycosylated recombinant lectin and both mutants, as measured by a higher Tm of denaturation or a greater free energy change, respectively. Reversibility experiments after thermal denaturation reveal that deglycosylated proteins tend to aggregate during thermal inactivation but the wild type shows a much greater recovery to the native state upon refolding. These results suggest that N-glycosylation in turmeric lectin is important for the maintenance of its proper folding upon changes in pH, and that the oligosaccharides help in maintaining the active conformation and prevent aggregation in unfolded or partially folded molecules. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Low mannose-binding lectin serum levels are associated with reduced kidney graft survival

    DEFF Research Database (Denmark)

    Bay, Jakob Thaning; Sørensen, Søren S; Hansen, Jesper M

    2013-01-01

    Activation of the complement system is initiated by the alternative, the classical, or the lectin pathway. As the complement system is involved in the pathophysiology of graft rejection after kidney transplantation, we investigated the possible role of mannose-binding lectin in kidney transplanta...... immunity in maintaining kidney graft survival, but these are probably overruled by HLA immunization.Kidney International advance online publication, 21 November 2012; doi:10.1038/ki.2012.373....

  9. Morphological variability, lectin binding and Na+,K+-activated adenosine triphosphatase activity of isolated Müller (glial) cells from the rabbit retina.

    Science.gov (United States)

    Reichenbach, A; Dettmer, D; Brückner, G; Neumann, M; Birkenmeyer, G

    1985-03-22

    Rabbit retinal Müller cells were isolated by means of papaine and mechanical dissociation. These cells were shown to have a well preserved morphology and to preserve viability for many hours. Intense wheat germ agglutinin binding occurs on the photoreceptor side of Müller cells, especially in the microvillous region. Rabbit retinal Müller cells have a Na+,K+-activated adenosine triphosphatase activity in the same order of magnitude as brain astroglial cells.

  10. Sugared biomaterial binding lectins: achievements and perspectives

    Czech Academy of Sciences Publication Activity Database

    Bojarová, Pavla; Křen, Vladimír

    2016-01-01

    Roč. 4, č. 8 (2016), s. 1142-1160 ISSN 2047-4830 R&D Projects: GA ČR GC15-02578J Institutional support: RVO:61388971 Keywords : C-TYPE LECTINS * AMPHIPHILIC JANUS GLYCODENDRIMERS * BIOMEDICALLY RELEVANT LECTINS Subject RIV: CE - Biochemistry Impact factor: 4.210, year: 2016

  11. Plant Lectins as Medical Tools against Digestive System Cancers.

    Science.gov (United States)

    Estrada-Martínez, Laura Elena; Moreno-Celis, Ulisses; Cervantes-Jiménez, Ricardo; Ferriz-Martínez, Roberto Augusto; Blanco-Labra, Alejandro; García-Gasca, Teresa

    2017-07-03

    Digestive system cancers-those of the esophagus, stomach, small intestine, colon-rectum, liver, and pancreas-are highly related to genetics and lifestyle. Most are considered highly mortal due to the frequency of late diagnosis, usually in advanced stages, caused by the absence of symptoms or masked by other pathologies. Different tools are being investigated in the search of a more precise diagnosis and treatment. Plant lectins have been studied because of their ability to recognize and bind to carbohydrates, exerting a variety of biological activities on animal cells, including anticancer activities. The present report integrates existing information on the activity of plant lectins on various types of digestive system cancers, and surveys the current state of research into their properties for diagnosis and selective treatment.

  12. Plant Lectins as Medical Tools against Digestive System Cancers

    Directory of Open Access Journals (Sweden)

    Laura Elena Estrada-Martínez

    2017-07-01

    Full Text Available Digestive system cancers—those of the esophagus, stomach, small intestine, colon-rectum, liver, and pancreas—are highly related to genetics and lifestyle. Most are considered highly mortal due to the frequency of late diagnosis, usually in advanced stages, caused by the absence of symptoms or masked by other pathologies. Different tools are being investigated in the search of a more precise diagnosis and treatment. Plant lectins have been studied because of their ability to recognize and bind to carbohydrates, exerting a variety of biological activities on animal cells, including anticancer activities. The present report integrates existing information on the activity of plant lectins on various types of digestive system cancers, and surveys the current state of research into their properties for diagnosis and selective treatment.

  13. Zinc-induced Self-association of Complement C3b and Factor H

    Science.gov (United States)

    Nan, Ruodan; Tetchner, Stuart; Rodriguez, Elizabeth; Pao, Po-Jung; Gor, Jayesh; Lengyel, Imre; Perkins, Stephen J.

    2013-01-01

    The sub-retinal pigment epithelial deposits that are a hallmark of age-related macular degeneration contain both C3b and millimolar levels of zinc. C3 is the central protein of complement, whereas C3u is formed by the spontaneous hydrolysis of the thioester bridge in C3. During activation, C3 is cleaved to form active C3b, then C3b is inactivated by Factor I and Factor H to form the C3c and C3d fragments. The interaction of zinc with C3 was quantified using analytical ultracentrifugation and x-ray scattering. C3, C3u, and C3b associated strongly in >100 μm zinc, whereas C3c and C3d showed weak association. With zinc, C3 forms soluble oligomers, whereas C3u and C3b precipitate. We conclude that the C3, C3u, and C3b association with zinc depended on the relative positions of C3d and C3c in each protein. Computational predictions showed that putative weak zinc binding sites with different capacities exist in all five proteins, in agreement with experiments. Factor H forms large oligomers in >10 μm zinc. In contrast to C3b or Factor H alone, the solubility of the central C3b-Factor H complex was much reduced at 60 μm zinc and even more so at >100 μm zinc. The removal of the C3b-Factor H complex by zinc explains the reduced C3u/C3b inactivation rates by zinc. Zinc-induced precipitation may contribute to the initial development of sub-retinal pigment epithelial deposits in the retina as well as reducing the progression to advanced age-related macular degeneration in higher risk patients. PMID:23661701

  14. Anaphylatoxin C3a induced mediator release from mast cells

    International Nuclear Information System (INIS)

    Herrscher, R.; Hugli, T.E.; Sullivan, T.J.

    1986-01-01

    The authors investigated the biochemical and functional consequences of the binding of highly purified human C3a to isolated rat serosal mast cells. C3a caused a dose-dependent (1-30 μM), noncytotoxic release of up to 64% (+/- 7 SEM) of the mast cell histamine content. C3a (10μM) increased 45 Ca ++ uptake 8.2- fold (+/- 2.2 SEM) above unstimulated control values within 10 minutes. Arachidonyl-diacylglycerol and arachidonyl-monoacylglycerol levels increased significantly within 2 minutes after C3a (10 μM) stimulation. Turnover of phosphatidylinositol, phosphatidic acid, and phosphatidylcholine were increased within 15 minutes. In contrast to antigen, C3a stimulation (10 μM) was not enhanced by exogenous phosphatidylserine, and was not inhibited by ethanol (100 μmM). C3a suppressed arachidonic acid (AA) release to 38% (+/- 9 SEM) below baseline, and did not cause PGD 2 formation. C3a and the desarginine form of C3a caused identical responses in all experiments. These studies indicate that C3a stimulation activates mast cell preformed mediator release in a manner very similar to antigen-IgE stimulation, but C3a suppresses free AA levels and does not stimulate PGD 2 synthesis

  15. Complement component 3 (C3)

    Science.gov (United States)

    ... the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic ... proteins may go down. For example, people with active lupus erythematosus may have lower-than-normal levels ...

  16. Effect of Algae and Plant Lectins on Planktonic Growth and Biofilm Formation in Clinically Relevant Bacteria and Yeasts

    Directory of Open Access Journals (Sweden)

    Mayron Alves Vasconcelos

    2014-01-01

    Full Text Available This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250 μg/mL. The lectins from Cratylia floribunda (CFL, Vatairea macrocarpa (VML, Bauhinia bauhinioides (BBL, Bryothamnion seaforthii (BSL, and Hypnea musciformis (HML showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining and by enumerating the viable cells (colony-forming units. The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins.

  17. Multivalent Carbohydrate-Lectin Interactions: How Synthetic Chemistry Enables Insights into Nanometric Recognition

    Directory of Open Access Journals (Sweden)

    René Roy

    2016-05-01

    Full Text Available Glycan recognition by sugar receptors (lectins is intimately involved in many aspects of cell physiology. However, the factors explaining the exquisite selectivity of their functional pairing are not yet fully understood. Studies toward this aim will also help appraise the potential for lectin-directed drug design. With the network of adhesion/growth-regulatory galectins as therapeutic targets, the strategy to recruit synthetic chemistry to systematically elucidate structure-activity relationships is outlined, from monovalent compounds to glyco-clusters and glycodendrimers to biomimetic surfaces. The versatility of the synthetic procedures enables to take examining structural and spatial parameters, alone and in combination, to its limits, for example with the aim to produce inhibitors for distinct galectin(s that exhibit minimal reactivity to other members of this group. Shaping spatial architectures similar to glycoconjugate aggregates, microdomains or vesicles provides attractive tools to disclose the often still hidden significance of nanometric aspects of the different modes of lectin design (sequence divergence at the lectin site, differences of spatial type of lectin-site presentation. Of note, testing the effectors alone or in combination simulating (pathophysiological conditions, is sure to bring about new insights into the cooperation between lectins and the regulation of their activity.

  18. Griffithsin: An Antiviral Lectin with Outstanding Therapeutic Potential

    Directory of Open Access Journals (Sweden)

    Sabrina Lusvarghi

    2016-10-01

    Full Text Available Griffithsin (GRFT, an algae-derived lectin, is one of the most potent viral entry inhibitors discovered to date. It is currently being developed as a microbicide with broad-spectrum activity against several enveloped viruses. GRFT can inhibit human immunodeficiency virus (HIV infection at picomolar concentrations, surpassing the ability of most anti-HIV agents. The potential to inhibit other viruses as well as parasites has also been demonstrated. Griffithsin’s antiviral activity stems from its ability to bind terminal mannoses present in high-mannose oligosaccharides and crosslink these glycans on the surface of the viral envelope glycoproteins. Here, we review structural and biochemical studies that established mode of action and facilitated construction of GRFT analogs, mechanisms that may lead to resistance, and in vitro and pre-clinical results that support the therapeutic potential of this lectin.

  19. Chitovibrin: a chitin-binding lectin from Vibrio parahemolyticus.

    Science.gov (United States)

    Gildemeister, O S; Zhu, B C; Laine, R A

    1994-12-01

    A novel 134 kDa, calcium-independent chitin-binding lectin, 'chitovibrin', is secreted by the marine bacterium Vibrio parahemolyticus, inducible with chitin or chitin-oligomers. Chitovibrin shows no apparent enzymatic activity but exhibits a strong affinity for chitin and chito-oligomers > dp9. The protein has an isoelectric pH of 3.6, shows thermal tolerance, binds chitin with an optimum at pH 6 and is active in 0-4 M NaCl. Chitovibrin appears to be completely different from other reported Vibrio lectins and may function to bind V. parahemolyticus to chitin substrates, or to capture or sequester chito-oligomers. It may be a member of a large group of recently described proteins in Vibrios related to a complex chitinoclastic (chitinivorous) system.

  20. The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus Sordaria macrospora.

    Science.gov (United States)

    Nowrousian, Minou; Cebula, Patricia

    2005-11-03

    The filamentous fungus Sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was tap1 (transcript associated with perithecial development), a gene encoding a putative lectin homolog. Analysis of tap1 transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that tap1 is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the tap1 open reading frame and adjoining sequences. The genomic region comprising tap1 is syntenic to its homologous region in the closely related filamentous fungus Neurospora crassa. To determine whether tap1 is involved in fruiting body development in S. macrospora, a knockout construct was generated in which the tap1 open reading frame was replaced by the hygromycin B resistance gene hph under the control of fungal regulatory regions. Transformation of the S. macrospora wild type with this construct resulted in a tap1 deletion strain where tap1 had been replaced by the hph cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Deltatap1 allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains. The tap1 transcript is strongly upregulated during sexual development in S. macrospora; however, analysis of a tap1 knockout strain shows that tap1 is not essential for fruiting body formation in S. macrospora.

  1. The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus Sordaria macrospora

    Directory of Open Access Journals (Sweden)

    Cebula Patricia

    2005-11-01

    Full Text Available Abstract Background The filamentous fungus Sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was tap1 (transcript associated with perithecial development, a gene encoding a putative lectin homolog. Results Analysis of tap1 transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that tap1 is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the tap1 open reading frame and adjoining sequences. The genomic region comprising tap1 is syntenic to its homologous region in the closely related filamentous fungus Neurospora crassa. To determine whether tap1 is involved in fruiting body development in S. macrospora, a knockout construct was generated in which the tap1 open reading frame was replaced by the hygromycin B resistance gene hph under the control of fungal regulatory regions. Transformation of the S. macrospora wild type with this construct resulted in a tap1 deletion strain where tap1 had been replaced by the hph cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Δtap1 allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains. Conclusion The tap1 transcript is strongly upregulated during sexual development in S. macrospora; however, analysis of a tap1 knockout strain shows that tap1 is not essential for fruiting body formation in S. macrospora.

  2. The Importance of the C3 Framework

    Science.gov (United States)

    Social Education, 2013

    2013-01-01

    "The C3 Framework for Social Studies State Standards will soon be released under the title "The College, Career, and Civic Life (C3) Framework for Social Studies State Standards: State Guidance for Enhancing the Rigor of K-12 Civics, Economics, Geography, and History." The C3 Project Director and Lead Writer was NCSS member Kathy…

  3. Recent Progress in Lectin-Based Biosensors

    Directory of Open Access Journals (Sweden)

    Baozhen Wang

    2015-12-01

    Full Text Available This article reviews recent progress in the development of lectin-based biosensors used for the determination of glucose, pathogenic bacteria and toxins, cancer cells, and lectins. Lectin proteins have been widely used for the construction of optical and electrochemical biosensors by exploiting the specific binding affinity to carbohydrates. Among lectin proteins, concanavalin A (Con A is most frequently used for this purpose as glucose- and mannose-selective lectin. Con A is useful for immobilizing enzymes including glucose oxidase (GOx and horseradish peroxidase (HRP on the surface of a solid support to construct glucose and hydrogen peroxide sensors, because these enzymes are covered with intrinsic hydrocarbon chains. Con A-modified electrodes can be used as biosensors sensitive to glucose, cancer cells, and pathogenic bacteria covered with hydrocarbon chains. The target substrates are selectively adsorbed to the surface of Con A-modified electrodes through strong affinity of Con A to hydrocarbon chains. A recent topic in the development of lectin-based biosensors is a successful use of nanomaterials, such as metal nanoparticles and carbon nanotubes, for amplifying output signals of the sensors. In addition, lectin-based biosensors are useful for studying glycan expression on living cells.

  4. Differential effect of plant lectins on mast cells of different origins

    Directory of Open Access Journals (Sweden)

    F.C. Lopes

    2005-06-01

    Full Text Available Histamine release induced by plant lectins was studied with emphasis on the carbohydrate specificity, external calcium requirement, metal binding sites, and mast cell heterogeneity and on the importance of antibodies bound to the mast cell membrane to the lectin effect. Peritoneal mast cells were obtained by direct lavage of the rat peritoneal cavity and guinea pig intestine and hamster cheek pouch mast cells were obtained by dispersion with collagenase type IA. Histamine release was induced with concanavalin A (Con A, lectins from Canavalia brasiliensis, mannose-specific Cymbosema roseum, Maackia amurensis, Parkia platycephala, Triticum vulgaris (WGA, and demetallized Con A and C. brasiliensis, using 1-300 µg/ml lectin concentrations applied to Wistar rat peritoneal mast cells, peaking on 26.9, 21.0, 29.1, 24.9, 17.2, 10.7, 19.9, and 41.5%, respectively. This effect was inhibited in the absence of extracellular calcium. The lectins were also active on hamster cheek pouch mast cells (except demetallized Con A and on Rowett nude rat (animal free of immunoglobulins peritoneal mast cells (except for mannose-specific C. roseum, P. platycephala and WGA. No effect was observed in guinea pig intestine mast cells. Glucose-saturated Con A and C. brasiliensis also released histamine from Wistar rat peritoneal mast cells. These results suggest that histamine release induced by lectins is influenced by the heterogeneity of mast cells and depends on extracellular calcium. The results also suggest that this histamine release might occur by alternative mechanisms, because the usual mechanism of lectins is related to their binding properties to metals from which depend the binding to sugars, which would be their sites to bind to immunoglobulins. In the present study, we show that the histamine release by lectins was also induced by demetallized lectins and by sugar-saturated lectins (which would avoid their binding to other sugars. Additionally, the lectins

  5. Rachycentron canadum (cobia) lectin promoted mitogenic response in mice BALB/c splenocytes.

    Science.gov (United States)

    Coriolano, M C; de Melo, C M L; Santos, A J G; Pereira, V R A; Coelho, L C B B

    2012-12-01

    The mitogenic lectins are invaluable tools to study the biochemical changes associated with lymphocyte activation and proliferation of various immune cells. Rachycentron canadum lectin (RcaL) was detected and purified from serum of cobia fish. The aim of this study was to evaluate the proliferative response and cytokine production in splenocytes of mice in vitro stimulated with RcaL lectin; Canavalia ensiformis lectin (Con A) was used as positive control. A high proliferation index was induced by RcaL in relation to control cells. Furthermore, RcaL induced higher IL-2 and IL-6 production in relation to control. The cell viability was 90% in splenocytes treated with RcaL lectin, but RcaL promoted significant late apoptosis after 24 and 48 h in relation to control. RcaL induced proliferative responses suggesting that this lectin can be used as a mitogenic agent in immunostimulatory assays. © 2012 The Authors. Scandinavian Journal of Immunology © 2012 Blackwell Publishing Ltd.

  6. Incident microalbuminuria and complement factor mannan-binding lectin-associated protein 19 in people with newly diagnosed type 1 diabetes

    DEFF Research Database (Denmark)

    Ostergaard, J A; Thiel, S; Hoffmann-Petersen, I T

    2017-01-01

    BACKGROUND: Evidence links the lectin pathway of complement activation to diabetic kidney disease. Upon carbohydrate-recognition by pattern-recognition molecules, e.g., mannan-binding lectin (MBL), the MBL-associated serine protease (MASP-2) is activated and initiates the complement cascade. The ...

  7. Technical Report on the Development of Novel Technology for Reducing the Toxicity of Mistletoe Lectin by using Radiation Fusion Technology

    International Nuclear Information System (INIS)

    Lee, Ju Woon; Kim, Jae Hun; Choi, Jong Il; Song, Beom Seok; Yoon, Yo Han; Jung, Pil Mun; Sung, Nak Yun

    2009-10-01

    The aim of this study was conducted to investigate the effect of irradiation on detoxification, structural change, and physiological change of Mistletoe lectin. Optimal irradiation dose was determined from the result of having maximum detoxification and remaining the immunological activity Irradiation technology could be effective method for detoxification of Mistletoe lectin containing the immunological activity. The results indicate the feasibility of novel technology for reduction of the toxicity of Mistletoe lectin by using radiation technology. Practical state though clinical test is needed to extend biomedicine field using radiation technology and improve of public health by the control of the disease that gradually increase every year

  8. Photosynthetic carbon assimilation in the coccolithophorid Emiliania huxleyi (Haptophyta): Evidence for the predominant operation of the c3 cycle and the contribution of {beta}-carboxylases to the active anaplerotic reaction.

    Science.gov (United States)

    Tsuji, Yoshinori; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2009-02-01

    The coccolithophorid Emiliania huxleyi (Haptophyta) is a representative and unique marine phytoplankton species that fixes inorganic carbon by photosynthesis and calci-fication. We examined the initial process of photosynthetic carbon assimilation by analyses of metabolites, enzymes and genes. When the cells were incubated with a radioactive substrate (2.3 mM NaH(14)CO(3)) for 10 s under illumination, 70% of the (14)C was incorporated into the 80% methanol-soluble fraction. Eighty-five and 15% of (14)C in the soluble fraction was incorporated into phosphate esters (P-esters), including the C(3) cycle intermediates and a C(4) compound, aspartate, respectively. A pulse-chase experiment showed that (14)C in P-esters was mainly transferred into lipids, while [(14)C]aspartate, [(14)C]alanine and [(14)C]glutamate levels remained almost constant. These results indicate that the C(3) cycle functions as the initial pathway of carbon assimilation and that beta-carboxylation contributes to the production of amino acids in subsequent metabolism. Transcriptional analysis of beta-carboxylases such as pyruvate carboxylase (PYC), phosphoenolpyruvate carboxylase (PEPC) and phosphoenolpyruvate carboxykinase (PEPCK) revealed that PYC and PEPC transcripts were greatly increased under illumination, whereas the PEPCK transcript decreased remarkably. PEPC activity was higher in light-grown cells than in dark-adapted cells. PYC activity was detected in isolated chloroplasts of light-grown cells. According to analysis of their deduced N-terminal sequence, PYC and PEPC are predicted to be located in the chloroplasts and mitochondria, respectively. These results suggest that E. huxleyi possesses unique carbon assimila-tion mechanisms in which beta-carboxylation by both PYC and PEPC plays important roles in different organelles.

  9. Lectin binding patterns and immunohistochemical antigen detection ...

    African Journals Online (AJOL)

    Ibrahim Eldaghayes

    2018-02-09

    Feb 9, 2018 ... placenta and lungs of Brucella abortus-bovine infected fetuses. María Andrea ... The present lectin histochemical study revealed a distinctive pattern of oligosaccharide .... tissue was used as a positive control and nonimmune.

  10. Lectin receptors in the human cornea.

    Science.gov (United States)

    Holmes, M J; Mannis, M J; Lund, J; Jacobs, L

    Five different biotin labeled lectins, Concanavalin-A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA1), Ulex europaeus agglutinin (UEA1), and soybean agglutinin (SBA) were used to study lectin receptors on formalin-fixed paraffin embedded human corneas. Con A stained the cytoplasm, cell, and nuclear membranes of the epithelial cells and stained the stroma diffusely. WGA stained the superficial epithelial cells, the epithelial cell membranes, and the keratocytes of the stroma. SBA did not react with any of the corneal layers. RCA1 heavily stained the keratocytes but did not stain the epithelium. UEA1 lightly stained the epithelial cell cytoplasm and interstitial stroma. All staining reactions could be abolished by omission of the lectin or by the use of the appropriate inhibitory sugar. The lectin binding patterns reported here provide a means for further investigation of carbohydrate structures in the human cornea in both normal and disease states.

  11. Lectin binders. A new group of plant proteins

    Energy Technology Data Exchange (ETDEWEB)

    Rudiger, H; Gebauer, G; Gansera, R; Schurz, H; Schimpl, A [Wuerzburg Univ. (Germany, F.R.)

    1982-09-01

    Lectins are widely distributed in the plant kingdom, many of them being well characterized in their chemical structure and the effects they have on alien biological systems such as erythrocytes or lymphocytes. The biological function of plant lectins remains speculative. We therefore inspected plant extracts from components which might bind specifically to the lectin from the respective plant. Single proteins (lectin binders) could be isolated from each plant extract. The interaction of these proteins with lectins was demonstrated and qualified by several methods. Similar to the lectins, the lectin binders are localized in the cytoplasm in contrast to them, however, they persist during germination and plant growth. Their precise role in the plant is not known, but they are likely to be associated with lectins not only in vitro but also in vivo. They also interact with alien cells, and are able to stimulate mitosis in murine lymphocytes. Some lectin binders act specifically on B lymphocytes, leaving T cells uninfluenced.

  12. Lectin interactions with alpha-galactosylated xenoantigens

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Moe, Dennis

    2002-01-01

    alpha-Galactosylated xenoantigens (Galalpha1-3Galbeta1-4GlcNAcbeta1 and Galalpha1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) are often detected with the alpha-Gal specific lectin Griffonia simplicifolia 1 isolectin B4 (GS1 B4). However, this lectin exhibits a broad and variable specificity for carboh...

  13. Mannose-binding lectin and Ficolin-2 gene polymorphisms predispose to cytomegalovirus (re)infection after orthotopic liver transplantation

    NARCIS (Netherlands)

    de Rooij, Bert-Jan F.; van der Beek, Martha T.; van Hoek, Bart; Vossen, Ann C. T. M.; ten Hove, W. Rogier; Roos, Anja; Schaapherder, Alexander F.; Porte, Robert J.; van der Reijden, Johan J.; Coenraad, Minneke J.; Hommes, Daniel W.; Verspaget, Hein W.

    2011-01-01

    Background & Aims: The lectin pathway of complement activation is a crucial effector cascade of the innate immune response to pathogens. Cytomegalovirus (CMV) infection occurs frequently in immunocompromised patients after orthotopic liver transplantation (OLT). Single-nucleotide polymorphisms

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

    Science.gov (United States)

    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

  15. Effects of plant lectins on in vitro fibroblast proliferation

    Directory of Open Access Journals (Sweden)

    Ana Maria Sell

    2003-06-01

    Full Text Available Lectins are carbohydrate-binding proteins that have been isolated from various sources and presented a wide spectrum of biological activities. The effects of four lectins, namely, Phaseolus vulgaris phytohemagglutinin, PHA, wheat germ agglutinin, WGA, Artocarpus integrifolia seed lectins, jacalin and artocarpin, on in vitro fibroblasts proliferation were investigated. The lectins did not influence the initial cell adhesion to the plate. PHA and WGA at 10-20 µg/mL concentrations significantly decreased fibroblasts proliferation. At these concentrations, they caused morphological alterations on cells and over 80 µg/mL, promoted cell death. Neither jacalin nor artocarpin significantly affected cell proliferation.O objetivo deste trabalho foi avaliar a influência das lectinas PHA, WGA, jacalina e artocarpina sobre a proliferação de fibroblastos in vitro. Para tanto, fibroblastos gengivais de voluntários saudáveis foram cultivados, por cinco dias, em DMEM suplementado com soro bovino fetal (10% v/v e na presença das lectinas nas concentrações finais de 0.1 a 300 µg/mL. A adesão, o crescimento e a morfologia celular foram acompanhados por microscopia de inversão e contraste de fase. O índice de proliferação foi avaliado pelo método calorimétrico usando MTT. As lectinas não alteraram a adesão inicial dos fibroblastos à placa de poliestireno. PHA e WGA, nas concentrações de 10 a 20 µg/mL, diminuíram significativamente a proliferação celular. Nestas concentrações a morfologia celular é alterada e acima de 80 µg/mL, houve100% de morte celular. As lectinas jacalina e artocarpina não influenciaram a proliferação celular.

  16. Current concepts in C3 glomerulopathy

    Directory of Open Access Journals (Sweden)

    S Thomas

    2014-01-01

    Full Text Available Complement component 3 glomerulopathy (C3G is a recently defined entity comprising of dense deposit disease and C3 glomerulonephritis. The key histological feature is the presence of isolated C3 deposits without immunoglobulins. Often masqueradng as some of the common glomerulonephritides this is a prototype disorder occurring from dysregulated alternate complement pathway with recently identified genetic defects and autoantibodies. We review the pathophysiology, clinical features, and diagnostic and treatment strategies.

  17. Skipping of exon 27 in C3 gene compromises TED domain and results in complete human C3 deficiency.

    Science.gov (United States)

    da Silva, Karina Ribeiro; Fraga, Tatiana Rodrigues; Lucatelli, Juliana Faggion; Grumach, Anete Sevciovic; Isaac, Lourdes

    2016-05-01

    Primary deficiency of complement C3 is rare and usually associated with increased susceptibility to bacterial infections. In this work, we investigated the molecular basis of complete C3 deficiency in a Brazilian 9-year old female patient with a family history of consanguinity. Hemolytic assays revealed complete lack of complement-mediated hemolytic activity in the patient's serum. While levels of the complement regulatory proteins Factor I, Factor H and Factor B were normal in the patient's and family members' sera, complement C3 levels were undetectable in the patient's serum and were reduced by at least 50% in the sera of the patient's parents and brother. Additionally, no C3 could be observed in the patient's plasma and cell culture supernatants by Western blot. We also observed that patient's skin fibroblasts stimulated with Escherichia coli LPS were unable to secrete C3, which might be accumulated within the cells before being intracellularly degraded. Sequencing analysis of the patient's C3 cDNA revealed a genetic mutation responsible for the complete skipping of exon 27, resulting in the loss of 99 nucleotides (3450-3549) located in the TED domain. Sequencing of the intronic region between the exons 26 and 27 of the C3 gene (nucleotides 6690313-6690961) showed a nucleotide exchange (T→C) at position 6690626 located in a splicing donor site, resulting in the complete skipping of exon 27 in the C3 mRNA. Copyright © 2016. Published by Elsevier GmbH.

  18. Purification, subunit characterization and ultrastructure of three soluble bovine lectins: conglutinin, mannose-binding protein and the pentraxin serum amyloid P-component

    DEFF Research Database (Denmark)

    Andersen, Ove; Friis, P; Holm Nielsen, E

    1992-01-01

    affinity chromatography and selective elution was developed. The purification was monitored by SDS-PAGE, Western blotting and electron microscopy. Binding of the lectins to Sephadex-iC3b, their collagenase sensitivity, and the size and antibody reactivity of their subunits was investigated....... The demonstration, by SDS-PAGE, of 25-kDa subunits, which were unaffected by collagenase treatment but bound to Sephadex-iC3b and antibodies to human SAP, indicated the existence of bovine SAP. Bovine conglutinin (BK) also showed calcium-dependent binding to Sephadex-iC3b, whereas bovine MBP did not. The binding...... of BK was inhibitable with GlcNAc. A 3000-fold increase in BK activity (ELISA) was obtained in eluates from Sephadex-iC3b. SDS-PAGE analyses of BK and MBP revealed subunits with an Mr of 43 kDa and 30 kDa, respectively. These subunits were sensitive to collagenase treatment which reduced the Mr to 20 k...

  19. Circulating mannan-binding lectin, M-, L-, H-ficolin and collectin-liver-1 levels in patients with acute liver failure

    DEFF Research Database (Denmark)

    Laursen, Tea Lund; Sandahl, Thomas D; Støy, Sidsel

    2015-01-01

    BACKGROUND & AIMS: The complement system is activated in liver diseases including acute liver failure (ALF); however, the role of the lectin pathway of complement has scarcely been investigated in ALF. The pathway is initiated by soluble pattern recognition molecules: mannan-binding lectin (MBL),...

  20. Effects of plant lectin from cobra lily, Arisaema curvatum Kunth on development of melon fruit fly, Bactrocera cucurbitae (Coq.).

    Science.gov (United States)

    Singh, Kuljinder; Kaur, Manpreet; Rup, Pushpinder J; Singh, Jatinder

    2008-11-01

    The lectin from tubers of cobra lily, Arisaema curvatum Kunth was purified by affinity chromatography using asialofetuin-linked amino activated porous silica beads. The concentration dependent effect of lectin was studied on second instar larvae (64-72 hr) of Bactrocera cucurbitae (Coq.). The treatment not only resulted in a significant reduction in the percentage pupation and emergence of the adults from treated larvae but it also prolonged the remaining larval development period. A very low LC50 value, 39 mgl(-1) of lectin was obtained on the basis of adult emergence using probit analysis. The activity of three hydrolase enzymes (esterases, acid and alkaline phosphatases), one oxidoreductase (catalase) and one group transfer enzyme (GSTs: Glutathione S-transferases) was assayed in second instar larvae under the influence of the LC50 of lectin at increasing exposure intervals (0, 24, 48 and 72 hr). The Arisaema curvatum lectin significantly decreased the activity of all the enzymes except for esterases, where the activity increased as compared to control at all exposure intervals. The decrease in pupation and emergence as well as significant suppression in the activities of two hydrolases, one oxidoreductase and one GST enzyme in treated larvae of B. cucurbitae indicated that this lectin has anti-metabolic effect on the melon fruit fly larvae.

  1. Structure prediction and functional analysis of a non-permutated lectin from Dioclea grandiflora.

    Science.gov (United States)

    de Sousa, Bruno Lopes; Nagano, Celso Shiniti; Simões, Rafael da Conceição; Silva-Filho, José Caetano; Cunha, Rodrigo Maranguape da Silva; Cajazeiras, João Batista; do Nascimento, Kyria Santiago; Cavada, Benildo Sousa

    2016-12-01

    Legume lectins have been widely studied and applied for many purposes in the last few decades, but many of their physiological aspects remain elusive. The Diocleinae legume subtribe, which includes intensively explored lectins, such as ConA, presents an unusual and extensive post-translational process which results in minor alterations in protein structure, in turn making its function elusive. Despite previous reports about Diocleinae precursor activity, no structural or functional analyses have ever been carried out to understand the impacts of post-translational processing relative to lectin structure and binding specificity. Here we analyzed the functionality of a non glycosylated, recombinantly expressed lectin precursor from Dioclea grandiflora through inhibition assays, corroborating the experimental data with structural information generated by molecular modeling, docking calculations and molecular dynamics simulations. We demonstrate that Diocleinae precursors are active and share the same carbohydrate specificity as mature lectins. At the same time, however, subtle structural alterations were detected and mostly result in an "incomplete" functionality of the precursor, as consequence of an immature binding site and an unstructured tetramer interface, affecting carbohydrate binding and oligomer formation, respectively. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  2. Critical role for cross-linking of trimeric lectin domains of surfactant protein D in antiviral activity against influenza A virus

    DEFF Research Database (Denmark)

    Tecle, Tesfaldet; White, Mitchell R; Sørensen, Grith Lykke

    2008-01-01

    binding activity for some ligands and mediate some functional activities. The lung collectin SP-D (surfactant protein D) has strong neutralizing activity for IAVs (influenza A viruses) in vitro and in vivo, however, the NCRD derived from SP-D has weak viral-binding ability and lacks neutralizing activity...

  3. C3a Enhances the Formation of Intestinal Organoids through C3aR1

    Directory of Open Access Journals (Sweden)

    Naoya Matsumoto

    2017-09-01

    Full Text Available C3a is important in the regulation of the immune response as well as in the development of organ inflammation and injury. Furthermore, C3a contributes to liver regeneration but its role in intestinal stem cell function has not been studied. We hypothesized that C3a is important for intestinal repair and regeneration. Intestinal organoid formation, a measure of stem cell capacity, was significantly limited in C3-deficient and C3a receptor (C3aR 1-deficient mice while C3a promoted the growth of organoids from normal mice by supporting Wnt-signaling but not from C3aR1-deficient mice. Similarly, the presence of C3a in media enhanced the expression of the intestinal stem cell marker leucine-rich repeat G-protein-coupled receptor 5 (Lgr5 and of the cell proliferation marker Ki67 in organoids formed from C3-deficient but not from C3aR1-deficient mice. Using Lgr5.egfp mice we showed significant expression of C3 in Lgr5+ intestinal stem cells whereas C3aR1 was expressed on the surface of various intestinal cells. C3 and C3aR1 expression was induced in intestinal crypts in response to ischemia/reperfusion injury. Finally, C3aR1-deficient mice displayed ischemia/reperfusion injury comparable to control mice. These data suggest that C3a through interaction with C3aR1 enhances stem cell expansion and organoid formation and as such may have a role in intestinal regeneration.

  4. Changes in cell surface structure by viral transformation studied by binding of lectins differing in sugar specificity.

    Science.gov (United States)

    Tsuda, M; Kurokawa, T; Takeuchi, M; Sugino, Y

    1975-10-01

    Changes in cell surface structure by viral transformation were studied by examining changes in the binding of various lectins differing in carbohydrate specificities. Binding of lectins was assayed directly using cells grown in coverslips. The following 125I-lectins were used: Concanavalin-A (specific for glucose and mannose), wheat germ agglutinin (specific for N-acetylglucosamine), castor bean agglutinin (specific for galactose), Wistaria floribunda agglutinin (specific for N-acetylgalactosamine), and soybean agglutinin (specific for N-acetyl-galactosamine). Cells for a clone, SS7, transformed by bovine adenovirus type-3, were found to bind 5 to 6 times more Wistaria floribunda agglutinin than the normal counterpart cells (clone C31, from C3H mouse kidney). In contrast, the binding of soybean agglutinin, which has a sugar specificity similar to Wistaria floribunda agglutinin, to normal and transformed cells was similar. The binding of wheat germ agglutinin and castor bean agglutinin, respectively, to normal and transformed cells was also similar. However, normal cells bound twice as much concanavalin-A as transformed cells. Only half as much Wistaria floribunda agglutinin was bound to transformed cells when they had been dispersed with EDTA. These changes in the number of lectin binding sites on transformation are thought to reflect alteration of the cell surface structure. The amount of lectins bound per cell decreased with increase in cell density, especially in the case of binding of Wistaria floribunda agglutinin to normal cells.

  5. Complementary Roles of the Classical and Lectin Complement Pathways in the Defense against Aspergillus fumigatus

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2016-01-01

    Aspergillus fumigatus infections are associated with a high mortality rate for immunocompromised patients. The complement system is considered to be important in protection against this fungus, yet the course of activation is unclear. The aim of this study was to unravel the role of the classical......, lectin, and alternative pathways under both immunocompetent and immunocompromised conditions to provide a relevant dual-perspective on the response against A. fumigatus. Conidia (spores) from a clinical isolate of A. fumigatus were combined with various human serum types (including serum deficient...... complement on A. fumigatus, but required classical and/or lectin pathway for initiation. In normal human serum, this initiation came primarily from the classical pathway. However, with a dysfunctional classical pathway (C1q-deficient serum), lectin pathway activated complement and mediated opsonophagocytosis...

  6. Soybean Lectin Enhances Biofilm Formation by Bradyrhizobium japonicum in the Absence of Plants

    Directory of Open Access Journals (Sweden)

    Julieta Pérez-Giménez

    2009-01-01

    Full Text Available Soybean lectin (SBL purified from soybean seeds by affinity chromatography strongly bound to Bradyrhizobium japonicum USDA 110 cell surface. This lectin enhanced biofilm formation by B. japonicum in a concentration-dependent manner. Presence of galactose during biofilm formation had different effects in the presence or absence of SBL. Biofilms were completely inhibited in the presence of both SBL and galactose, while in the absence of SBL, galactose was less inhibitory. SBL was very stable, since its agglutinating activity of B. japonicum cells as well as of human group A+ erythrocytes was resistant to preincubation for one week at 60°C. Hence, we propose that plant remnants might constitute a source of this lectin, which might remain active in soil and thus favor B. japonicum biofilm formation in the interval between soybean crop seasons.

  7. Visualisation of lectin binding sites on the surface of human platelets using lectins adsorbed to gold granules.

    Science.gov (United States)

    Nurden, A T; Horisberger, M; Savariau, E; Caen, J P

    1980-10-15

    Washed human platelets have been incubated with the lectins WGA, ConA and RCA1, adsorbed to different-sized gold particles. Plasma membrane receptors for each lectin were then located by scanning and transmission electron microscopy.

  8. Rapid affinity-purification and physicochemical characterization of pumpkin (Cucurbita maxima) phloem exudate lectin.

    Science.gov (United States)

    Narahari, Akkaladevi; Swamy, Musti J

    2010-04-21

    The chito-oligosaccharide-specific lectin from pumpkin (Cucurbita maxima) phloem exudate has been purified to homogeneity by affinity chromatography on chitin. After SDS/PAGE in the presence of 2-mercaptoethanol, the pumpkin phloem lectin yielded a single band corresponding to a molecular mass of 23.7 kDa, whereas ESI-MS (electrospray ionization MS) gave the molecular masses of the subunit as 24645 Da. Analysis of the CD spectrum of the protein indicated that the secondary structure of the lectin consists of 9.7% alpha-helix, 35.8% beta-sheet, 22.5% beta-turn and 32.3% unordered structure. Saccharide binding did not significantly affect the secondary and tertiary structures of the protein. The haemagglutinating activity of pumpkin phloem lectin was mostly unaffected in the temperature range 4-70 degrees C, but a sharp decrease was seen between 75 and 85 degrees C. Differential scanning calorimetric and CD spectroscopic studies suggest that the lectin undergoes a co-operative thermal unfolding process centred at approx. 81.5 degrees C, indicating that it is a relatively stable protein.

  9. Recombinant production of plant lectins in microbial systems for biomedical application – the frutalin case study

    Directory of Open Access Journals (Sweden)

    Carla eOliveira

    2014-08-01

    Full Text Available Frutalin is a homotetrameric partly-glycosylated alpha-D-galactose-binding lectin of biomedical interest from Artocarpus incisa (breadfruit seeds, belonging to the jacalin-related lectins family. As other plant lectins, frutalin is a heterogeneous mixture of several isoforms possibly with distinct biological activities. The main problem of using such lectins as biomedical tools is that batch-to-batch variation in isoforms content may lead to inconstant results. The production of lectins by recombinant means has the advantage of obtaining high amounts of proteins with defined amino-acid sequences and more precise properties. In this mini review, we provide the strategies followed to produce two different forms of frutalin in two different microbial systems: Escherichia coli and Pichia pastoris. The processing and functional properties of the recombinant frutalin obtained from these hosts are compared to those of frutalin extracted from breadfruit. Emphasis is given particularly to recombinant frutalin produced in P. pastoris, which showed a remarkable capacity as biomarker of human prostate cancer and as apoptosis-inducer of cancer cells. Recombinant frutalin production opens perspectives for its development as a new tool in human medicine.

  10. Recombinant production of plant lectins in microbial systems for biomedical application – the frutalin case study

    Science.gov (United States)

    Oliveira, Carla; Teixeira, José A.; Domingues, Lucília

    2014-01-01

    Frutalin is a homotetrameric partly glycosylated α-D-galactose-binding lectin of biomedical interest from Artocarpus incisa (breadfruit) seeds, belonging to the jacalin-related lectins family. As other plant lectins, frutalin is a heterogeneous mixture of several isoforms possibly with distinct biological activities. The main problem of using such lectins as biomedical tools is that “batch-to-batch” variation in isoforms content may lead to inconstant results. The production of lectins by recombinant means has the advantage of obtaining high amounts of proteins with defined amino-acid sequences and more precise properties. In this mini review, we provide the strategies followed to produce two different forms of frutalin in two different microbial systems: Escherichia coli and Pichia pastoris. The processing and functional properties of the recombinant frutalin obtained from these hosts are compared to those of frutalin extracted from breadfruit. Emphasis is given particularly to recombinant frutalin produced in P. pastoris, which showed a remarkable capacity as biomarker of human prostate cancer and as apoptosis-inducer of cancer cells. Recombinant frutalin production opens perspectives for its development as a new tool in human medicine. PMID:25152749

  11. The C-type lectin OCILRP2 costimulates EL4 T cell activation via the DAP12-Raf-MAP kinase pathway.

    Science.gov (United States)

    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.

  12. The C-type lectin OCILRP2 costimulates EL4 T cell activation via the DAP12-Raf-MAP kinase pathway.

    Directory of Open Access Journals (Sweden)

    Qiang Lou

    Full Text Available 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.

  13. Burn injury reveals altered phenotype in mannan-binding lectin-deficient mice

    DEFF Research Database (Denmark)

    Møller-Kristensen, Mette; Hamblin, Michael R; Thiel, Steffen

    2007-01-01

    Burn injury destroys skin, the second largest innate immune organ in the body, and triggers chaotic immune and inflammatory responses. The pattern recognition molecule, mannan-binding lectin (MBL), plays an important role in the first-line host defense against infectious agents. MBL initiates...... the lectin complement pathway and acts as an opsonin. Recent studies suggest that MBL also modulates inflammatory responses. We report that local responses after burn in MBL null mice differ from those found in wild-type (WT) mice in the following important biological markers: spontaneous eschar separation......, thinned epidermis and dermis, upregulation of soluble factors including cytokines, chemokines, cell adhesion molecules, a growth factor-binding protein, and matrix metalloproteinases. Mice lacking C1q, C4, or C3 did not show the lack of eschar separation seen in MBL null-burn phenotype. These findings...

  14. Effects of indian coral tree, Erythrina indica lectin on eggs and larval development of melon fruit fly, Bactrocera cucurbitae.

    Science.gov (United States)

    Singh, Kuljinder; Kaur, Manpreet; Rup, Pushpinder J; Singh, Jatinder

    2009-07-01

    Present study was undertaken to investigate the influence of D-galactose binding lectin from Erythrina indica Lam. on the eggs and second instar larvae (64-72 hr) of melon fruit fly, Bactrocera cucurbitae (Coquillett). The lectin from E. indica seeds was extracted and purified by affinity chromatography using asilofetuin linked porous amino activated silica beads. The effects of various concentrations (0, 125, 250, 500 and 1000 microg ml(-1)) of lectin were studied on freshly laid eggs (0-8 hr) of B. cucurbitae which showed non-significant reduction in percent hatching of eggs. However, the treatment of second instar larvae (64-72 hr) with various test concentrations (0, 25, 50, 100 and 200 microg ml(-1)) of lectin significantly reduced the percent pupation and percent emergence of B. cucurbitae depicting a negative correlation with the lectin concentration. The LC50 (81 microg ml(-1)) treatment significantly decreased the pupal weight. Moreover, the treatment of larvae had also induced a significant increase in the remaining development duration. The activity of three hydrolase enzymes (esterases, acid and alkaline phosphatases), one oxidoreductase (catalase) and one group transfer enzyme (glutathione S-transferases) was assayed in second instar larvae under the influence of LC50 concentration of lectin for three exposure intervals (24, 48 and 72 hr). It significantly suppressed the activity of all the enzymes after all the three exposure intervals except for esterases which increased significantly.

  15. Unfolding energetics and stability of banana lectin.

    Science.gov (United States)

    Gupta, Garima; Sinha, Sharmistha; Surolia, Avadhesha

    2008-08-01

    The unfolding pathway of banana lectin from Musa paradisiaca was determined by isothermal denaturation induced by the chaotrope GdnCl. The unfolding was found to be a reversible process. The data obtained by isothermal denaturation provided information on conformational stability of banana lectin. The high values of DeltaG of unfolding at various temperatures indicated the strength of intersubunit interactions. It was found that banana lectin is a very stable and denatures at high chaotrope concentrations only. The basis of the stability may be attributed to strong hydrogen bonds of the order 2.5-3.1 A at the dimeric interface along with the presence of water bridges. This is perhaps very unique example in proteins where subunit association is not a consequence of the predominance of hydrophobic interactions. (c) 2008 Wiley-Liss, Inc.

  16. Anti-insect potential of lectins from Arisaema species towards Bactrocera cucurbitae.

    Science.gov (United States)

    Kaur, Manpreet; Singh, Kuljinder; Rup, Pushpinder J; Kamboj, Sukhdev Singh; Singh, Jatinder

    2009-11-01

    Bactrocera cucurbitae (Coquillett), also known as melon fruit fly, is one of the major insect pests of cucurbits in several parts of Asia, Africa and Pacific. In the present investigation, effect of lectins from two sources i.e. Arisaema intermedium Blume and Arisaema wallichianum Hook f. (Family-Araceae) has been studied on the development of second instar larvae of melon fruit fly. The lectins were incorporated separately in artificial diet at a concentration of 10 to 160 microg ml(-1) and fed adlibitum to the second instar larvae. Both the lectins were found to prolong the development period and significantly inhibited the pupation and emergence in a dose dependent manner. Total development period was found to be prolonged by 3.5 and 2.3 days in case of larvae fed on artificial diet containing A. intermedium (AIL) and A. wallichianum (AWL), respectively. LC50 values calculated on the basis of adult emergence came out to be 32.8 and 29 microg ml(-1) for AIL and AWL, respectively. Both the lectins tested, were found to increase the activity of esterases as larvae proceeded from 24 to 72 hr of treatment. The activity of acid phosphatase decreased significantly in larvae reared on diet containing LC50 of AIL, while in case of AWL significant decrease was observed only at 72 hr of treatment. Alkaline phosphatase activity decreased significantly on treatment with both of these lectins. These results showed that AIL and AWL have promising anti-insect potential. So, lectin gene/s from either of these species can be cloned and subsequently can be employed to develop transgenics to control melon fruit flies specifically and insect pests in general. This approach could be used as a part of Integrated pest management (IPM) strategies.

  17. The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Vengadesan [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Xu, Yuanyuan [Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Macon, Kevin [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Volanakis, John E. [Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Narayana, Sthanam V. L., E-mail: narayana@uab.edu [Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294 (United States)

    2009-03-01

    The crystal structure of C2b has been determined at 1.8 Å resolution, which reveals the arrangement of its three complement control protein (CCP) modules. A model for complement component C2 is presented and its conformational changes during the C3-convertase formation are also discussed. The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The formation of these convertases requires the Mg{sup 2+}-dependent binding of C2 to C4b and the subsequent cleavage of C2 by C1s or MASP2, respectively. The crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 Å resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b–C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein.

  18. The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation

    International Nuclear Information System (INIS)

    Krishnan, Vengadesan; Xu, Yuanyuan; Macon, Kevin; Volanakis, John E.; Narayana, Sthanam V. L.

    2009-01-01

    The crystal structure of C2b has been determined at 1.8 Å resolution, which reveals the arrangement of its three complement control protein (CCP) modules. A model for complement component C2 is presented and its conformational changes during the C3-convertase formation are also discussed. The second component of complement (C2) is a multi-domain serine protease that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The formation of these convertases requires the Mg 2+ -dependent binding of C2 to C4b and the subsequent cleavage of C2 by C1s or MASP2, respectively. The crystal structure of full-length C2 is not yet available, although the structure of its C-terminal catalytic segment C2a has been determined. The crystal structure of the N-terminal segment C2b of C2 determined to 1.8 Å resolution presented here reveals the arrangement of its three CCP domains. The domains are arranged differently compared with most other CCP-domain assemblies, but their arrangement is similar to that found in the Ba part of the full-length factor B structure. The crystal structures of C2a, C2b and full-length factor B are used to generate a model for C2 and a discussion of the domain association and possible interactions with C4b during formation of the C4b–C2 complex is presented. The results of this study also suggest that upon cleavage by C1s, C2a domains undergo conformational rotation while bound to C4b and the released C2b domains may remain folded together similar to as observed in the intact protein

  19. Influence of Lithium Carbonate on C3A Hydration

    Directory of Open Access Journals (Sweden)

    Weiwei Han

    2018-01-01

    Full Text Available Lithium salts, known to ameliorate the effects of alkali-silica reaction, can make significant effects on cement setting. However, the mechanism of effects on cement hydration, especially the hydration of C3A which is critical for initial setting time of cement, is rarely reported. In this study, the development of pH value of pore solution, conductivity, thermodynamics, and mineralogical composition during hydration of C3A with or without Li2CO3 are investigated. The results demonstrate that Li2CO3 promotes C3A hydration through high alkalinity, due to higher activity of lithium ion than that of calcium ion in the solution and carbonation of C3A hydration products resulted from Li2CO3. Li2CO3 favors the C3A hydration in C3A-CaSO4·2H2O-Ca(OH2-H2O hydration system and affects the mineralogical variation of the ettringite phase(s.

  20. Separation and Enrichment of Lectin from Zihua Snap-Bean (Phaseolus vulgaris Seeds by PEG 600–Ammonium Sulfate Aqueous Two-Phase System

    Directory of Open Access Journals (Sweden)

    Bin Jiang

    2017-09-01

    Full Text Available A fast and efficient method based on a polyethylene glycol (PEG 600/(NH42SO4 aqueous two-phase system for extracting lectin from Zihua snap-bean (Phaseolus vulgaris seeds was established. According to a Box–Behnken design (BBD, involving four factors at three levels each subjected to analysis of variance (ANOVA and response surface analysis, the protein recovery and the purification factor of lectin in the top phase were used as the response values of the variance analysis to acquire the multivariate quadratic regression model. SDS–PAGE electrophoresis and the hemagglutination test were used to detect the distribution of lectin in the aqueous two-phase system (ATPS. The obtained data indicated that lectin was preferentially partitioned into the PEG-rich phase, and the ATPS, composed of 15% (NH42SO4 (w/w, 18% PEG 600 (w/w, 0.4 g/5 g NaCl and 1 mL crude extract, showed good selectivity for lectin when the pH value was 7.5. Under the optimal conditions, most of the lectin was assigned to the top phase in the ATPS, and the hemagglutination activity of the purified lectin in the top phase was 3.08 times that of the crude extract. Consequently, the PEG 600/(NH42SO4 aqueous two-phase system was an effective method for separating and enriching lectin directly from the crude extract of Zihua snap-bean seeds.

  1. Isolation and Molecular Characterization of Two Lectins from Dwarf Elder (Sambucus ebulus L. Blossoms Related to the Sam n1 Allergen

    Directory of Open Access Journals (Sweden)

    Tomas Girbes

    2013-10-01

    Full Text Available Sambucus species contain a number of lectins with and without antiribosomal activity. Here, we show that dwarf elder (Sambucus ebulus L. blossoms express two D-galactose-binding lectins that were isolated and purified by affinity chromatography and gel filtration. These proteins, which we named ebulin blo (A-B toxin and SELblo (B-B lectin—blo from blossoms—were subjected to molecular characterization and analysis by MALDI-TOF mass spectrometry and tryptic peptide fingerprinting. Both lectins share a high degree of amino acid sequence homology with Sambucus lectins related to the Sam n1 allergen. Ebulin blo, but not SELblo, was highly toxic by nasal instillation to mice. Overall, our results suggested that both lectins would belong to an allergen family exemplified by Sam n1 and could trigger allergy responses. Furthermore, they raise a concern about ebulin blo toxicity.

  2. Structural characterization of coagulant Moringa oleifera Lectin and its effect on hemostatic parameters.

    Science.gov (United States)

    Luz, Luciana de Andrade; Silva, Mariana Cristina Cabral; Ferreira, Rodrigo da Silva; Santana, Lucimeire Aparecida; Silva-Lucca, Rosemeire Aparecida; Mentele, Reinhard; Oliva, Maria Luiza Vilela; Paiva, Patricia Maria Guedes; Coelho, Luana Cassandra Breitenbach Barroso

    2013-07-01

    Lectins are carbohydrate recognition proteins. cMoL, a coagulant Moringa oleifera Lectin, was isolated from seeds of the plant. Structural studies revealed a heat-stable and pH resistant protein with 101 amino acids, 11.67 theoretical pI and 81% similarity with a M. oleifera flocculent protein. Secondary structure content was estimated as 46% α-helix, 12% β-sheets, 17% β-turns and 25% unordered structures belonging to the α/β tertiary structure class. cMoL significantly prolonged the time required for blood coagulation, activated partial thromboplastin (aPTT) and prothrombin times (PT), but was not so effective in prolonging aPTT in asialofetuin presence. cMoL acted as an anticoagulant protein on in vitro blood coagulation parameters and at least on aPTT, the lectin interacted through the carbohydrate recognition domain. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. A unique epidermal mucus lectin identified from catfish (Silurus asotus): first evidence of intelectin in fish skin slime.

    Science.gov (United States)

    Tsutsui, Shigeyuki; Komatsu, Yukie; Sugiura, Takaya; Araki, Kyosuke; Nakamura, Osamu

    2011-11-01

    The present study reports a new type of skin mucus lectin found in catfish Silurus asotus. The lectin exhibited calcium-dependent mannose-binding activity. When mannose eluate from chromatography with mannose-conjugated agarose was analysed by SDS-PAGE, the lectin appeared as a single 35-kDa band. Gel filtration showed that the lectin forms monomers and dimers. A 1216-bp cDNA sequence obtained by RACE-PCR from the skin encoded a 308 amino acid secretory protein with homology to mammalian and fish intelectins. RT-PCR demonstrated that the lectin gene was expressed in the gill, kidney and skin. Subsequent sequencing revealed the presence of an isoform in the gills. Antiserum detected the intelectin protein in club cells in the skin and gill, renal tubules and blood plasma. Although intelectin gene expression was not induced by in vivo bacterial stimulation, the intelectin showed agglutination activity against the pathogenic bacterium Aeromonas salmonicida, suggesting that the lectin plays an important role in self-defence against bacteria in the skin surface of the catfish. These findings represent one of the few examples of characterization and functional analysis of a fish intelectin protein.

  4. Macrophage galactose-type C-type lectin receptor for DC targeting of antitumor glycopeptide vaccines

    DEFF Research Database (Denmark)

    Nuti, M; Zizzari, I; Napoletano, C

    2011-01-01

    e13528 Background: Dendritic cells (DCs) are the most potent antigen presenting cells and are employed in cancer vaccination. Several receptors are being studied in order to identif strategies to increase DCs activating capacity. The C-type lectin macrophage galactose type C-type lectin (MGL...... of IFNg and IL-2 secretion by both CD8 and CD4 T cells. CONCLUSIONS: These results demonstrate that MGL engagement profoundly affects DC plasticity inducing and directing a Th1 immune response. Moreover, MGL receptor expressed on human DC can be targeted by glycopeptide based vaccines with adjuvant...

  5. Chemical modification of the lectin of the marine coral Gerardia savaglia by marine quinone avarone

    Directory of Open Access Journals (Sweden)

    IVANA PAJIC

    2007-12-01

    Full Text Available The quinone avarone, isolated from the marine sponge Dysidea avara, possesses the ability to chemically modify proteins. In this work, modification of lectin isolated from the coral Gerardia savaglia by avarone was examined. The techniques used for studying the modification were: SDS PAGE, isoelectric focusing and hemagglutination testing. The results of the SDS PAGE indicate dimerization of the protein. A shift of the pI toward lower value occurs upon modification. The change of the hemagglutination activity of the protein confirms that chemical modification of G. savaglia lectin by avarone changes its ability to interact with the membrane of erythrocytes.

  6. Influence of Alternative Tubulin Inhibitors on the Potency of a Epirubicin-Immunochemotherapeutic Synthesized with an Ultra Violet Light-Activated Intermediate: Influence of incorporating an internal/integral disulfide bond structure and Alternative Tubulin/Microtubule Inhibitors on the Cytotoxic Anti-Neoplastic Potency of Epirubicin-(C3-amide)-Anti-HER2/neu Synthesized Utilizing a UV-Photoactivated Anthracycline Intermediate.

    Science.gov (United States)

    Coyne, C P; Jones, Toni; Bear, Ryan

    2012-11-01

    Immunochemotherapeutics, epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] with an internal disulfide bond, and epirubicin-(C 3 - amide )-[anti-HER2/ neu ] were synthesized utilizing succinimidyl 2-[(4,4'-azipentanamido) ethyl]-1,3'-dithioproprionate or succinimidyl 4,4-azipentanoate respectively. Western blot analysis was used to determine the presence of any immunoglobulin fragmentation or IgG-IgG polymerization. Retained HER2/ neu binding characteristics of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] were validated by cell-ELISA using a mammary adenocarcinoma (SKBr-3) population that highly over-expresses trophic HER2/ neu receptor complexes. Cytotoxic anti-neoplastic potency of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] between epirubicin-equivalent concentrations of 10 -10 M and 10 -6 M was determined by measuring the vitality/proliferation of chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3 cell type). Cytotoxic anti-neoplastic potency of benzimidazoles (albendazole, flubendazole, membendazole) and griseofulvin were assessed between 0-to-2 μg/ml and 0-to-100 μg/ml respectively while mebendazole and griseofulvin were analyzed at fixed concentrations of 0.35 μg/ml and 35 g/ml respectively in dual combination with gradient concentrations of epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ]. Cytotoxic anti-neoplastic potency for epirubicin-(C 3 - amide )-[anti-HER2/ neu ] and epirubicin-(C 3 - amide )-SS-[anti-HER2/ neu ] against chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3) was nearly identical at epirubicin-equivalent concentrations of 10 -10 M and 10 -6 M. The benzimadazoles also possessed cytotoxic anti-neoplastic activity with flubendazole and albendazole being the most and least potent respectively. Similarly, griseofulvin had cytotoxic anti-neoplastic activity and was more potent than

  7. A survey of domestic species of Basidiomycetes fungi for the presence of lectins inn their carpophores

    Directory of Open Access Journals (Sweden)

    Grażyna Końska

    2014-01-01

    Full Text Available Preliminary investigations were conducted to determine the presence of active lectins in carpophores of fungi from the class Basidiomycetes, collected from natural localities in southern and south-eastern Poland. The degree of agglutination activity (expressed as the titre of agglutination of aqueous extracts was determined at room temperature (18-20°C and at +4°C in respect to human and animal erythrocytes suspended in physiological saline, part of which were additionally treated with proteolytic enzymes. From among the 104 tested species, extracts from 41 of them showed agglutination activity, among which 18 were high. In six cases, specific activity against human ABH group antigens was found. Extracts from 5 species agglutinated only animal erythrocytes, with pigeon erythrocytes being exceptionally sensitive to the lectins. Extracts from two species had distinctly higher agglutination activity at 4°C, which suggests that lectins of the "cold" agglutinin type are present in these species. Analysis of extracts from caps and stems showed that caps had a higher lectin content.

  8. Altered glycosylation of complexed native IgG molecules is associated with disease activity of systemic lupus erythematosus.

    Science.gov (United States)

    Sjöwall, C; Zapf, J; von Löhneysen, S; Magorivska, I; Biermann, M; Janko, C; Winkler, S; Bilyy, R; Schett, G; Herrmann, M; Muñoz, L E

    2015-05-01

    In addition to the redundancy of the receptors for the Fc portion of immunoglobulins, glycans result in potential ligands for a plethora of lectin receptors found in immune effector cells. Here we analysed the exposure of glycans containing fucosyl residues and the fucosylated tri-mannose N-type core by complexed native IgG in longitudinal serum samples of well-characterized patients with systemic lupus erythematosus. Consecutive serum samples of a cohort of 15 patients with systemic lupus erythematosus during periods of increased disease activity and remission were analysed. All patients fulfilled the 1982 American College of Rheumatology classification criteria. Sera of 15 sex- and age-matched normal healthy blood donors served as controls. The levels and type of glycosylation of complexed random IgG was measured with lectin enzyme-immunosorbent assays. After specifically gathering IgG complexes from sera, biotinylated lectins Aleuria aurantia lectin and Lens culinaris agglutinin were employed to detect IgG-associated fucosyl residues and the fucosylated tri-mannose N-glycan core, respectively. In sandwich-ELISAs, IgG-associated IgM, IgA, C1q, C3c and C-reactive protein (CRP) were detected as candidates for IgG immune complex constituents. We studied associations of the glycan of complexed IgG and disease activity according to the physician's global assessment of disease activity and the systemic lupus erythematosus disease activity index 2000 documented at the moment of blood taking. Our results showed significantly higher levels of Aleuria aurantia lectin and Lens culinaris agglutinin binding sites exposed on IgG complexes of patients with systemic lupus erythematosus than on those of normal healthy blood donors. Disease activity in systemic lupus erythematosus correlated with higher exposure of Aleuria aurantia lectin-reactive fucosyl residues by immobilized IgG complexes. Top levels of Aleuria aurantia lectin-reactivity were found in samples taken during the

  9. Glycans: bioactive signals decoded by lectins.

    Science.gov (United States)

    Gabius, Hans-Joachim

    2008-12-01

    The glycan part of cellular glycoconjugates affords a versatile means to build biochemical signals. These oligosaccharides have an exceptional talent in this respect. They surpass any other class of biomolecule in coding capacity within an oligomer (code word). Four structural factors account for this property: the potential for variability of linkage points, anomeric position and ring size as well as the aptitude for branching (first and second dimensions of the sugar code). Specific intermolecular recognition is favoured by abundant potential for hydrogen/co-ordination bonds and for C-H/pi-interactions. Fittingly, an array of protein folds has developed in evolution with the ability to select certain glycans from the natural diversity. The thermodynamics of this reaction profits from the occurrence of these ligands in only a few energetically favoured conformers, comparing favourably with highly flexible peptides (third dimension of the sugar code). Sequence, shape and local aspects of glycan presentation (e.g. multivalency) are key factors to regulate the avidity of lectin binding. At the level of cells, distinct glycan determinants, a result of enzymatic synthesis and dynamic remodelling, are being defined as biomarkers. Their presence gains a functional perspective by co-regulation of the cognate lectin as effector, for example in growth regulation. The way to tie sugar signal and lectin together is illustrated herein for two tumour model systems. In this sense, orchestration of glycan and lectin expression is an efficient means, with far-reaching relevance, to exploit the coding potential of oligosaccharides physiologically and medically.

  10. Binding of peanut lectin to germinal-centre cells: a marker for B-cell subsets of follicular lymphoma?

    OpenAIRE

    Rose, M. L.; Habeshaw, J. A.; Kennedy, R.; Sloane, J.; Wiltshaw, E.; Davies, A. J.

    1981-01-01

    The binding of horseradish-peroxidase-labelled peanut lectin (HRP-PNL) to cryostat sections of tonsil, lymphoma lymph nodes, reactive lymph nodes and miscellaneous tumours demonstrated that PNL binds selectively to lymphocytes in germinal centres. Lymph nodes from 21 patients with non-Hodgkin's lymphomas were phenotyped as cell suspensions for PNL binding, and the following surface markers: E rosetting, C3d, SIg, OK markers of T-cell subsets, Ig heavy-chain and light-chain classes. There was ...

  11. New crystal forms of Diocleinae lectins in the presence of different dimannosides

    International Nuclear Information System (INIS)

    Moreno, Frederico Bruno Mendes Batista; Bezerra, Gustavo Arruda; Oliveira, Taianá Maia de; Souza, Emmanuel Prata de; Rocha, Bruno Anderson Matias da; Benevides, Raquel Guimarães; Delatorre, Plínio; Cavada, Benildo Sousa; Azevedo, Walter Filgueira Jr de

    2006-01-01

    The crystallization and preliminary X-ray data of Canavalia gladiata lectin (CGL) and C. maritima lectin (CML) complexed with Man(α1-2)Man(α1)OMe, Man(α1-3)Man(α1)OMe and Man(α1-4)Man(α1)OMe in two crystal forms [the complexes with Man(α1-3)Man(α1)OMe and Man(α1-4)Man(α1)OMe crystallized in space group P3 2 and those with Man(α1-2)Man(α1)OMe crystallized in space group I222], which differed from those of the native proteins (P2 1 2 1 2 for CML and C222 for CGL), are reported. Studying the interactions between lectins and sugars is important in order to explain the differences observed in the biological activities presented by the highly similar proteins of the Diocleinae subtribe. Here, the crystallization and preliminary X-ray data of Canavalia gladiata lectin (CGL) and C. maritima lectin (CML) complexed with Man(α1-2)Man(α1)OMe, Man(α1-3)Man(α1)OMe and Man(α1-4)Man(α1)OMe in two crystal forms [the complexes with Man(α1-3)Man(α1)OMe and Man(α1-4)Man(α1)OMe crystallized in space group P3 2 and those with Man(α1-2)Man(α1)OMe crystallized in space group I222], which differed from those of the native proteins (P2 1 2 1 2 for CML and C222 for CGL), are reported. The crystal complexes of ConA-like lectins with Man(α1-4)Man(α1)OMe are reported here for the first time

  12. Antiviral lectins from red and blue-green algae show potent in vitro and in vivo activity against hepatitis C virus.

    Directory of Open Access Journals (Sweden)

    Yutaka Takebe

    Full Text Available Hepatitis C virus (HCV infection is a significant public health problem with over 170,000,000 chronic carriers and infection rates increasing worldwide. Chronic HCV infection is one of the leading causes of hepatocellular carcinoma which was estimated to result in ∼10,000 deaths in the United States in the year 2011. Current treatment options for HCV infection are limited to PEG-ylated interferon alpha (IFN-α, the nucleoside ribavirin and the recently approved HCV protease inhibitors telaprevir and boceprevir. Although showing significantly improved efficacy over the previous therapies, treatment with protease inhibitors has been shown to result in the rapid emergence of drug-resistant virus. Here we report the activity of two proteins, originally isolated from natural product extracts, which demonstrate low or sub-nanomolar in vitro activity against both genotype I and genotype II HCV. These proteins inhibit viral infectivity, binding to the HCV envelope glycoproteins E1 and E2 and block viral entry into human hepatocytes. In addition, we demonstrate that the most potent of these agents, the protein griffithsin, is readily bioavailable after subcutaneous injection and shows significant in vivo efficacy in reducing HCV viral titers in a mouse model system with engrafted human hepatocytes. These results indicate that HCV viral entry inhibitors can be an effective component of anti-HCV therapy and that these proteins should be studied further for their therapeutic potential.

  13. conformational complexity of complement component C3

    NARCIS (Netherlands)

    Janssen, B.J.C.

    2007-01-01

    The complement system is an important part of the immune system and critical for the elimination of pathogens. In mammals the complement system consists of an intricate set of about 35 soluble and cell-surface plasma proteins. Central to complement is component C3, a large protein of 1,641 residues.

  14. Genetics Home Reference: C3 glomerulopathy

    Science.gov (United States)

    ... Harris CL, Holers VM, Johnson S, Lavin PJ, Medjeral-Thomas N, Paul Morgan B, Nast CC, Noel LH, Peters DK, Rodríguez de Córdoba S, Servais A, Sethi S, Song WC, Tamburini P, Thurman JM, Zavros M, Cook HT. C3 glomerulopathy: consensus report. Kidney Int. 2013 ...

  15. The Development of the C3 Framework

    Science.gov (United States)

    Social Education, 2013

    2013-01-01

    Susan Griffin, executive director of NCSS, was chair of the Task Force of Professional Organizations that initiated and guided the development of "The College, Career, and Civic Life (C3) Framework for Social Studies State Standards", which will soon be released. In this interview with "Social Education", Susan explains how the…

  16. Antinociceptive and Anti-inflammatory Effects of a Lectin-Like Substance from Clitoria fairchildiana R. Howard Seeds

    Directory of Open Access Journals (Sweden)

    Tatiane Santi-Gadelha

    2012-03-01

    Full Text Available Lectins are proteins that have the ability to bind specifically and reversibly to carbohydrates and glycoconjugates, without altering the structure of the glycosyl ligand. They are found in organisms such as viruses, plants and humans, and they have been shown to possess important biological activities. The objective of this study was to purify and characterize lectins in the seeds of Clitoria fairchildiana, as well as to verify their biological activities. The results indicated the presence of a lectin (CFAL in the glutelin acid protein fraction, which agglutinated native rabbit erythrocytes. CFAL was purified by column chromatography ion-exchange, DEAE-Sephacel, which was obtained from a peak of protein retained in the matrix by applying 0.5 M NaCl using the step-wise method. Electrophoretic analysis of this lectin in SDS-PAGE indicated a two band pattern protein molecular mass of approximately 100 and 116 kDa. CFAL proved to be unspecific to all carbohydrates/glycoconjugates in common use for the sugar inhibition test. This lectin showed no significant cytotoxicity to human red blood cells. It was observed that CFAL has anti-inflammatory activity in the paw edema induced by carrageenan model, in which a 64% diminution in edema was observed. Antinociceptive effects were observed for CFAL in the abdominal writhing test (induced by acetic acid, in which increasing doses of the lectin caused reduction in the number of contortions by up to 72%. It was concluded that the purified and characterized lectin from the seeds of Clitoria fairchildiana has anti-inflammatory and antinociceptive activity, and is not cytotoxic to human erythrocytes.

  17. Role of ascitic fluid C3 in spontaneous bacterial peritonitis | Kamal ...

    African Journals Online (AJOL)

    Background: The C3 component of complement tends to be reduced in cirrhosis and patients with reduced ascitic fluid C3 concentration and reduced opsonic activities have been shown to be predisposed to SBP. Aim of the work: To compare the level of ascitic fluid C3 concentration in cirrhotic patients with and without ...

  18. Lectins, Interconnecting Proteins with Biotechnological/Pharmacological and Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Luana Cassandra Breitenbach Barroso Coelho

    2017-01-01

    Full Text Available Lectins are proteins extensively used in biomedical applications with property to recognize carbohydrates through carbohydrate-binding sites, which identify glycans attached to cell surfaces, glycoconjugates, or free sugars, detecting abnormal cells and biomarkers related to diseases. These lectin abilities promoted interesting results in experimental treatments of immunological diseases, wounds, and cancer. Lectins obtained from virus, microorganisms, algae, animals, and plants were reported as modulators and tool markers in vivo and in vitro; these molecules also play a role in the induction of mitosis and immune responses, contributing for resolution of infections and inflammations. Lectins revealed healing effect through induction of reepithelialization and cicatrization of wounds. Some lectins have been efficient agents against virus, fungi, bacteria, and helminths at low concentrations. Lectin-mediated bioadhesion has been an interesting characteristic for development of drug delivery systems. Lectin histochemistry and lectin-based biosensors are useful to detect transformed tissues and biomarkers related to disease occurrence; antitumor lectins reported are promising for cancer therapy. Here, we address lectins from distinct sources with some biological effect and biotechnological potential in the diagnosis and therapeutic of diseases, highlighting many advances in this growing field.

  19. Ficolins and the lectin pathway of complement in patients with systemic lupus erythematosus

    DEFF Research Database (Denmark)

    Hein, Estrid; Nielsen, Louise Aas; Nielsen, Christoffer T

    2015-01-01

    The complement system plays a pathophysiological role in systemic lupus erythematosus (SLE). This study aims to investigate whether an association exists between the ficolins that are part of the lectin complement pathway and SLE. EDTA plasma samples from 68 Danish SLE patients and 29 healthy...... Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index] (SDI) (Rho=0.27, P=0.026). The Ficolin-1 concentration was also associated with the occurrence of arterial (P=0.0053) but not venous thrombosis (P=0.42). Finally, deposition of C4, C3 and TCC...

  20. C3 glomerulonephritis and dense deposit disease share a similar disease course in a large United States cohort of patients with C3 glomerulopathy.

    Science.gov (United States)

    Bomback, Andrew S; Santoriello, Dominick; Avasare, Rupali S; Regunathan-Shenk, Renu; Canetta, Pietro A; Ahn, Wooin; Radhakrishnan, Jai; Marasa, Maddalena; Rosenstiel, Paul E; Herlitz, Leal C; Markowitz, Glen S; D'Agati, Vivette D; Appel, Gerald B

    2018-04-01

    C3 glomerulonephritis (C3GN) and dense deposit disease comprise the two classes of C3 glomerulopathy. Studies from Europe and Asia have aided our understanding of this recently defined disorder, but whether these data apply to a diverse United States patient population remains unclear. We, therefore, reviewed clinical and histopathological data, including generation of a C3 Glomerulopathy Histologic Index to score biopsy activity and chronicity, to determine predictors of progression to end-stage renal disease (ESRD) and advanced chronic kidney disease (CKD) in 111 patients (approximately 35% non-white) with C3 glomerulopathy: 87 with C3GN and 24 with dense deposit disease. Complement-associated gene variants and autoantibodies were detected in 24% and 35% of screened patients, respectively. Our C3 Glomerulopathy Histologic Index denoted higher activity in patients with C3GN and higher chronicity in patients with dense deposit disease. Over an average of 72 months of follow-up, remission occurred in 38% of patients with C3GN and 25% of patients with dense deposit disease. Progression to late-stage CKD and ESRD was common, with no differences between C3GN (39%) and dense deposit disease (42%). In multivariable models, the strongest predictors for progression were estimated glomerular filtration rate at diagnosis (clinical variables model) and tubular atrophy/interstitial fibrosis (histopathology variables model). Using our C3 Glomerulopathy Histologic Index, both total activity and total chronicity scores emerged as the strongest predictors of progression. Thus, in a large, diverse American cohort of patients with C3 glomerulopathy, there is a high rate of progression to CKD and ESRD with no differences between C3GN and dense deposit disease. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  1. Use of lectin-functionalized particles for oral immunotherapy

    Science.gov (United States)

    Diesner, Susanne C; Wang, Xue-Yan; Jensen-Jarolim, Erika; Untersmayr, Eva; Gabor, Franz

    2013-01-01

    Immunotherapy, in recent times, has found its application in a variety of immunologically mediated diseases. Oral immunotherapy may not only increase patient compliance but may, in particular, also induce both systemic as well as mucosal immune responses, due to mucosal application of active agents. To improve the bioavailability and to trigger strong immunological responses, recent research projects focused on the encapsulation of drugs and antigens into polymer particles. These particles protect the loaded antigen from the harsh conditions in the GI tract. Furthermore, modification of the surface of particles by the use of lectins, such as Aleuria aurantia lectin, wheatgerm agglutinin or Ulex europaeus-I, enhances the binding to epithelial cells, in particular to membranous cells, of the mucosa-associated lymphoid tissue. Membranous cell-specific targeting leads to an improved transepithelial transport of the particle carriers. Thus, enhanced uptake and presentation of the encapsulated antigen by antigen-presenting cells favor strong systemic, but also local, mucosal immune responses. PMID:22834202

  2. Anti-Neuroblastoma Properties of a Recombinant Sunflower Lectin

    Directory of Open Access Journals (Sweden)

    Marcela Pinedo

    2017-01-01

    Full Text Available According to their sugar recognition specificity, plant lectins are proposed as bioactive proteins with potential in cancer treatment and diagnosis. Helja is a mannose-specific jacalin-like lectin from sunflower which was shown to inhibit the growth of certain fungi. Here, we report its recombinant expression in a prokaryotic system and its activity in neurobalstoma cells. Helja coding sequence was fused to the pET-32 EK/LIC, the enterokinase/Ligation-independent cloning vector and a 35 kDa protein was obtained in Escherichia coli representing Helja coupled to thioredoxin (Trx. The identity of this protein was verified using anti-Helja antibodies. This chimera, named Trx-rHelja, was enriched in the soluble bacterial extracts and was purified using Ni+2-Sepharose and d-mannose-agarose chromatography. Trx-rHelja and the enterokinase-released recombinant Helja (rHelja both displayed toxicity on human SH-SY5Y neuroblastomas. rHelja decreased the viability of these tumor cells by 75% according to the tetrazolium reduction assay, and microscopic analyses revealed that the cell morphology was disturbed. Thus, the stellate cells of the monolayer became spheroids and were isolated. Our results indicate that rHelja is a promising tool for the development of diagnostic or therapeutic methods for neuroblastoma cells, the most common solid tumors in childhood.

  3. A new method of lectin histochemistry for the study of brain angiogenesis. Lectin angiography.

    Science.gov (United States)

    Minamikawa, T; Miyake, T; Takamatsu, T; Fujita, S

    1987-01-01

    In an attempt to analyse the kinetics of angiogenesis in the brain, we developed a new lectin-histochemical staining technique for identifying the vasculature. Three horseradish-peroxidase-conjugated lectins, i.e., Griffonia simplicifolia agglutinin 1 (GS1), Ricinus communis agglutinin 1 (RCA1) and soybean agglutinin (SBA), selectively stained vascular walls in brain-tissue sections. When these lectins were injected into the circulation of ether-anesthetized animals via the pulsating left ventricle, they bound specifically to the inner surface of endothelial cells and revealed the three-dimensional architecture of the vascular network within thick tissue preparations. When this technique, referred to a lectin angiography, was combined with 5-bromo-2-deoxyuridine (BudR) immunohistochemistry, proliferating capillary cells could be easily identified in three-dimensional structures of the developing vasculature. Because of its simplicity and wide applicability, lectin angiography should be useful for analysing the kinetics of angiogenesis in developmental, regenerative, and pathological conditions in various tissues and organs.

  4. Lectins as endocytic ligands: an assessment of lectin binding and uptake to rabbit conjunctival epithelial cells.

    Science.gov (United States)

    Qaddoumi, Mohamed; Lee, Vincent H L

    2004-07-01

    To investigate the binding and uptake pattern of three plant lectins in rabbit conjunctival epithelial cells (RCECs) with respect to their potential for enhancing cellular macromolecular uptake. Three fluorescein-labeled plant lectins (Lycoperison esculentum, TL; Solanum tuberosum, STL; and Ulex europaeus 1, UEA-1) were screened with respect to time-, concentration-, and temperature-dependent binding and uptake. Chitin (30 mg/ml) and L-alpha-fucose (10 mM) were used as inhibitory sugars to correct for nonspecific binding of TL or STL and UEA-1, respectively. Confocal microscopy was used to confirm internalization of STL. The binding and uptake of all three lectins in RCECs was time-dependent (reaching a plateau at 1-2 h period) and saturable at 1-h period. The rank order of affinity constants (km) was STL>TL>UEA-1 with values of 0.39>0.48>4.81 microM, respectively. However, maximal, specific binding/uptake potential was in the order UEA-1>STL>TL with values of 53.7, 52.3, and 15.0 nM/mg of cell protein, respectively. Lectins showed temperature dependence in their uptake, with STL exhibiting the highest endocytic capacity. Internalized STL was visualized by confocal microscopy to be localized to the cell membrane and cytoplasm. Based on favorable binding and uptake characteristics, potato lectin appears to be a useful candidate for further investigation as an ocular drug delivery system.

  5. Effects of different elevated CO2 concentrations on chlorophyll contents, gas exchange, water use efficiency, and PSII activity on C3 and C4 cereal crops in a closed artificial ecosystem.

    Science.gov (United States)

    Wang, Minjuan; Xie, Beizhen; Fu, Yuming; Dong, Chen; Hui, Liu; Guanghui, Liu; Liu, Hong

    2015-12-01

    Although terrestrial CO2 concentrations [CO2] are not expected to reach 1000 μmol mol(-1) (or ppm) for many decades, CO2 levels in closed systems such as growth chambers and greenhouses can easily exceed this concentration. CO2 levels in life support systems (LSS) in space can exceed 10,000 ppm (1 %). In order to understand how photosynthesis in C4 plants may respond to elevated CO2, it is necessary to determine if leaves of closed artificial ecosystem grown plants have a fully developed C4 photosynthetic apparatus, and whether or not photosynthesis in these leaves is more responsive to elevated [CO2] than leaves of C3 plants. To address this issue, we evaluated the response of gas exchange, water use efficiency, and photosynthetic efficiency of PSII by soybean (Glycine max (L.) Merr., 'Heihe35') of a typical C3 plant and maize (Zea mays L., 'Susheng') of C4 plant under four CO2 concentrations (500, 1000, 3000, and 5000 ppm), which were grown under controlled environmental conditions of Lunar Palace 1. The results showed that photosynthetic pigment by the C3 plants of soybean was more sensitive to elevated [CO2] below 3000 ppm than the C4 plants of maize. Elevated [CO2] to 1000 ppm induced a higher initial photosynthetic rate, while super-elevated [CO2] appeared to negate such initial growth promotion for C3 plants. The C4 plant had the highest ETR, φPSII, and qP under 500-3000 ppm [CO2], but then decreased substantially at 5000 ppm [CO2] for both species. Therefore, photosynthetic down-regulation and a decrease in photosynthetic electron transport occurred by both species in response to super-elevated [CO2] at 3000 and 5000 ppm. Accordingly, plants can be selected for and adapt to the efficient use of elevated CO2 concentration in LSS.

  6. Genetically engineered fusion of MAP-1 and factor H domains 1-5 generates a potent dual upstream inhibitor of both the lectin and alternative complement pathways

    DEFF Research Database (Denmark)

    Nordmaj, Mie Anemone; Munthe-Fog, Lea; Hein, Estrid

    2015-01-01

    Inhibition of the complement cascade has emerged as an option for treatment of a range of diseases. Mannose-binding lectin/ficolin/collectin-associated protein (MAP-1) is a pattern recognition molecule (PRM)-associated inhibitor of the lectin pathway. The central regulator of the alternative......:4 in a solid-phase functional assay, only the first 5 N-terminal domains of complement FH fused to the C-terminal part of full-length MAP-1 chimeric construct were able to combine inhibition of lectin and AP activation with an half maximal inhibitory concentration of ∼ 100 and 20 nM, respectively. No effect...

  7. Mucosal immunogenicity of plant lectins in mice

    Science.gov (United States)

    Lavelle, E C; Grant, G; Pusztai, A; Pfüller, U; O’Hagan, D T

    2000-01-01

    The mucosal immunogenicity of a number of plant lectins with different sugar specificities was investigated in mice. Following intranasal (i.n.) or oral administration, the systemic and mucosal antibody responses elicited were compared with those induced by a potent mucosal immunogen (cholera toxin; CT) and a poorly immunogenic protein (ovalbumin; OVA). After three oral or i.n. doses of CT, high levels of specific serum antibodies were measured and specific IgA was detected in the serum, saliva, vaginal wash, nasal wash and gut wash of mice. Immunization with OVA elicited low titres of serum IgG but specific IgA was not detected in mucosal secretions. Both oral and i.n. delivery of all five plant lectins investigated [Viscum album (mistletoe lectin 1; ML‐1), Lycospersicum esculentum (tomato lectin; LEA), Phaseolus vulgaris (PHA), Triticum vulgaris (wheat germ agglutinin (WGA), Ulex europaeus I (UEA‐1)] stimulated the production of specific serum IgG and IgA antibody after three i.n. or oral doses. Immunization with ML‐1 induced high titres of serum IgG and IgA in addition to specific IgA in mucosal secretions. The response to orally delivered ML‐1 was comparable to that induced by CT, although a 10‐fold higher dose was administered. Immunization with LEA also induced high titres of serum IgG, particularly after i.n. delivery. Low specific IgA titres were also detected to LEA in mucosal secretions. Responses to PHA, WGA and UEA‐1 were measured at a relatively low level in the serum, and little or no specific mucosal IgA was detected. PMID:10651938

  8. Lectins discriminate between pathogenic and nonpathogenic South American trypanosomes

    International Nuclear Information System (INIS)

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

    1984-01-01

    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 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

  9. Lectins discriminate between pathogenic and nonpathogenic South American trypanosomes

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Application of lectins to tumor imaging radiopharmaceuticals

    International Nuclear Information System (INIS)

    Kojima, Shuji; Jay, M.

    1986-01-01

    We investigated the in vitro binding of 125 I-lectins to Ehrlich ascites tumor (EAT) cells and in vivo uptake of 125 I-lectins in Ehrlich solid tumor (EST) bearing mice. In in vitro binding assays, phaseolus vulgaris agglutinin (PHA), pisum sativum agglutinin (PSA), and concanavalia agglutinin (Con A) showed a high affinity for EAT cells. The in vivo biodistribution of 125 I-lectins showed 125 I-PSA to be significantly taken up into EST tissues 24 h postinjection. After IV injection of 125 I-PSA, uptake of the radioactivity into the tumor tissues reached a maximum at 6 h, and thereafter decreased. Rapid disappearance of the radioactivity from blood and its excretion into kidney soon after injection of 125 I-PSA were observed. When compared with the biodistribution of 67 Ga-citrate in EST bearing mice 24 h postinjection, tumor to liver (T/B), tumor to muscle (T/M), and tumor to blood (T/B) ratios were superior for 125 I-PSA. At 6 h postinjection, the T/B-ratio of 125 I-PSA was 2.5, and this value may be sufficient to enable discernable diagnostic images. Our results suggest that PSA might be a useful tumor imaging radiopharmaceutical. (orig.)

  11. Transmission-Blocking Antibodies against Mosquito C-Type Lectins for Dengue Prevention

    Science.gov (United States)

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

    2014-01-01

    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

  12. Evaluation of glycophenotype in breast cancer by quantum dot-lectin histochemistry

    Science.gov (United States)

    Andrade, Camila G; Cabral Filho, Paulo E; Tenório, Denise PL; Santos, Beate S; Beltrão, Eduardo IC; Fontes, Adriana; Carvalho, Luiz B

    2013-01-01

    Cell surface glycoconjugates play an important role in differentiation/dedifferentiation processes and lectins are employed to evaluate them by several methodologies. Fluorescent probes are considered a valuable tool because of their ability to provide a particular view, and are more detailed and sensitive in terms of cell structure and molecular content. The aim of this study was to evaluate and compare the expression and distribution of glycoconjugates in normal human breast tissue, and benign (fibroadenoma), and malignantly transformed (invasive ductal carcinoma) breast tissues. For this, we used mercaptosuccinic acid-coated Cadmium Telluride (CdTe) quantum dots (QDs) conjugated with concanavalin A (Con A) or Ulex europaeus agglutinin I (UEA I) lectins to detect α-D-glucose/mannose and L-fucose residues, respectively. The QD-lectin conjugates were evaluated by hemagglutination activity tests and carbohydrate inhibition assays, and were found to remain functional, keeping their fluorescent properties and carbohydrate recognition ability. Fluorescence images showed that different regions of breast tissue expressed particular types of carbohydrates. While the stroma was preferentially and intensely stained by QD-Con A, ductal cells were preferentially labeled by QD-UEA I. These results indicate that QD-lectin conjugates can be used as molecular probes and can help to elucidate the glycoconjugate profile in biological processes. PMID:24324334

  13. A new mannose-specific lectin from daylily (Hemerocallis fulva L. rhizome: purification and properties

    Directory of Open Access Journals (Sweden)

    V. O. Antonyuk

    2013-04-01

    Full Text Available A new lectin was purified from the daylily (Hemerocallis fulva L. with the yield of approximately 10 mg per kg of fresh plant rhizome. The purification procedure was based on application of the affinity chromathography on the column with yeast mannan and the ion-exchange chromatography on the column with DEAE-Toyopearl. The lectin possessed low affinity for α-methyl-D-mannopyranoside, D-fructose, D-turanose and 2-acetamido-D-galactopyranose and hight affinity for the yeast mannan. The lectin bound with greatly less affinity for the mannose-containig glycoproteins, such as ovoalbumin, ovomucoid and horseradish peroxidase. According to the results of electrophoresis in 20% DSNa-PAGE, the lectin consists of subunits of 12 kDa molecular weight. According to the results of gel-chromatography on the Toyopearl HW-55, the lectin’s molecular weight is 48 kDa. It agglutinated rabbit erythrocytes very well, while rat and guinea-pig erythrocytes were agglutinated worse, and human erythrocytes were not agglutinated at all. Lectin’s dialysis against 1% EDTA or heating to 60 ºC for 60 min did not stop its hemagglutinating activity.

  14. Three-dimensional structure of lectin from Dioclea violacea and comparative vasorelaxant effects with Dioclea rostrata

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, B.A.M.; Bezerra, M.J.B.; Bezerra, G.A.; Alencar, K.L.L.; Nascimento, K.S.; Naganao, C.S.; Sampaio, A.H.; Cavada, B.S. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Delatorre, P. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Rodrigues, N.V.; Pires, A.F.; Assreuy, A.M.S. [Universidade Estadual do Ceara (UECE), Fortaleza, CE (Brazil); Marins, J.L. [Universidade Federal de Pelotas (UFPel), Pelotas, RS (Brazil)

    2012-07-01

    Full text: Lectins are a structural heterogeneous group of proteins possessing at least one non-catalytic domain that binds reversibly to a specific mono or oligosaccharide. Diocleinae lectins exhibit glucose/mannose monosaccharide binding specificity and studies of their chemical and physicochemical properties revealed a high degree of identity in their amino acid sequences and three dimensional structures. This study investigated structural/functional relationships between lectins obtained from Dioclea violacea (DVL) and Dioclea rostrata (DRL). The purified lectin (DVL) was solubilized in 20 mM Tris-HCl pH 7.6 with 5 mM CaCl{sub 2} and MnCl{sub 2} buffer and incubated during one hour before the crystallization experiments with the ligand X-Man (5-bromo-4-chloro-3-indolyl-{alpha}-D-mannose) at 3 mM. Crystals of DVL grew in condition 33 of Crystal Screen I (4M Sodium formate) and belong to the orthorhombic space group I222. The structure of DVL at 2.6 resolution was obtained by molecular replacement using the coordinates of DRL (PDB code 2ZBJ), after the last refinement the structure presented R factor of 0.23 and R free of 0.27. The crystal structures reveal differences between them and could be related to relaxant activity. The conformation of residues HIS51, HIS131 and GLU205 and others positioned at CRD lead to different lectin binding activities. In fact, the pocket in DVL is small and deep and promotes weak interaction with carbohydrates, while DRL pocket is large and shallow, allowing strong interaction between CRD and sugars. This can explain why DVL and DRL elicited different degrees of aorta relaxation showing maximal effects of 43 % and 96 %, respectively. (author)

  15. Purification, characterization and biological effect of lectin from the marine sponge Stylissa flexibilis (Lévi, 1961).

    Science.gov (United States)

    Hung, Le Dinh; Ly, Bui Minh; Hao, Vo Thi; Trung, Dinh Thanh; Trang, Vo Thi Dieu; Trinh, Phan Thi Hoai; Ngoc, Ngo Thi Duy; Quang, Thai Minh

    2018-02-01

    SFL, a lectin from the marine sponge Stylissa flexibilis was purified by cold ethanol precipitation followed by ion exchange chromatography on DEAE Sepharose column and Sephacryl S-200 gel filtration. SFL is a dimeric glycoprotein of 32kDa subunits linked by a disulfide bridge with a molecular mass of 64kDa by SDS-PAGE and 65kDa by Sephacryl S-200 gel filtration. SFL preferentially agglutinated enzyme treated human A erythrocytes. The activity of lectin was strongly inhibited by monosaccharide d-galactose and glycoproteins asialo-porcine stomach mucin and asialo-fetuin. The lectin was Ca 2+ dependent, stable over a range of pH from 5 to 8, and up to 60°C for 30min. The N-terminal amino acid sequence of SFL was also determined and a blast search on amino acid sequences revealed that the protein showed similarity only with lectins from the marine sponge Spheciospongia vesparia. SFL caused agglutination of Vibrio alginolyticus and V. parahaemolyticus in a dose dependent manner and inhibited the growth rates of the virulent bacterial strains. Growth inhibition of V. alginolyticus and V. parahaemolyticus with SFL was not observed in the presence of d-galactose or asialo-porcine stomach mucin, suggesting that the lectin caused the agglutination through binding to the target receptor(s) on the surface of Vibrios. Thus, the marine sponge S. flexibilis could promise to be a good source of a lectin(s) that may be useful as a carbohydrate probe and an antibacterial reagent. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Interaction of hamster submaxillary sialyl-Tn and Tn glycoproteins with Gal, GalNAc and GlcNAc specific lectins.

    Science.gov (United States)

    Wu, A M; Shen, F; Herp, A; Wu, J H

    1994-04-01

    Hamster submaxillary glycoprotein (HSM), one of the simplest glycoproteins among mammalian salivary mucins, is composed of approximately equivalent amounts of protein, hexosamine and sialic acid. The Thr and Ser residues in the protein core account for more than half of all of the amino acid residues, while Lys, Glu, Pro and Ala are the major components of the remaining portion of amino acids. The carbohydrate side chains of this mucous glycoprotein have mainly the NeuAc-GalNAc-(sialyl-Tn) sequence (HSM), and those of the desialylated product (HSM-Tn) are almost exclusively unsubstituted GalNAc residues (Tn determinants). The binding properties of sialyl-Tn (HSM) and asialo-HSM (HSM-Tn) glycoproteins were tested by precipitin assay with Gal, GalNAc and GlcNAc specific lectins. The HSM-Tn completely precipitated Vicia villosa (VVL both B4 and mixture of A and B), Maclura pomifera (MPL), and Artocarpus integrifolia (Jacalin) lectins; less than 2 micrograms of HSM-Tn were required for precipitating 50% of 5.0-6.3 micrograms lectin nitrogen added. HSM-Tn also reacted well with Helix pomatia lectin (HPL), Wistaria floribunda lectin (WFL) and Abrus precatorius agglutinin (APA) and precipitated in each case over 81% of the lectin nitrogen added. The reactivity of HSM-Tn with other lectins (Ricinus communis, RCA1; Dolichol biflorus, DBL; Viscum album, ML-I; Arachis hypogaea, PNA, and Triticum vulgaris, WGA) was weak or negligible. The activity of sialyl-Tn (HSM) was more restricted; HSM reacted well with Jacalin, moderately with MPL and VVL-B4, but was inactive or only weakly with the other lectins used. These findings indicate that HSM and its desialylated product (HSM-Tn) are highly useful reagents for the differentiation of Tn and T/Gal specific lectins and for anti-T, Tn and Af monoclonal antibodies.

  17. Two Chitotriose-Specific Lectins Show Anti-Angiogenesis, Induces Caspase-9-Mediated Apoptosis and Early Arrest of Pancreatic Tumor Cell Cycle.

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    Ruby Singh

    Full Text Available The antiproliferative activity of two chito-specific agglutinins purified from Benincasa hispida (BhL and Datura innoxia (DiL9 of different plant family origin was investigated on various cancer cell lines. Both lectins showed chitotriose specificity, by inhibiting lectin hemagglutinating activity. On further studies, it was revealed that these agglutinins caused remarkable concentration-dependent antiproliferative effect on human pancreatic cancerous cells but not on the normal human umbilical vein endothelial cells even at higher doses determined using MTT assay. The GI50 values were approximately 8.4 μg ml(-1 (0.247 μM and 142 μg ml(-1 (14.8 μM for BhL and DiL9, respectively, against PANC-1 cells. The growth inhibitory effect of these lectins on pancreatic cancer cells were shown to be a consequence of lectin cell surface binding and triggering G0/G1 arrest, mitochondrial membrane depolarization, sustained increase of the intracellular calcium release and the apoptotic signal is amplified by activation of caspases executing cell death. Interestingly, these lectins also showed anti-angiogenic activity by disrupting the endothelial tubulogenesis. Therefore, we report for the first time two chito-specific lectins specifically binding to tumor glycans; they can be considered to be a class of molecules with antitumor activity against pancreatic cancer cells mediated through caspase dependent mitochondrial apoptotic pathway.

  18. Plant lectin can target receptors containing sialic acid, exemplified by podoplanin, to inhibit transformed cell growth and migration.

    Directory of Open Access Journals (Sweden)

    Jhon Alberto Ochoa-Alvarez

    Full Text Available 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.

  19. Extração da lectina da folha de mandioca (Manihot esculenta Crantz e o efeito de cátions divalentes na atividade hemaglutinante Extraction of the lectin of cassava leaves (Manihot esculenta Crantz and the effect of divalent cations on the hemagglutinating activity

    Directory of Open Access Journals (Sweden)

    Maria Cristina Silva

    2010-05-01

    Full Text Available Lectinas são proteínas ligantes de carboidratos, capazes de aglutinar eritrócitos, podendo exercer ação antinutricional. O isolamento destas proteínas tóxicas é interessante tanto pela sua ação antinutricional, como pela sua aplicação em biotecnologia. Algumas lectinas necessitam da presença de íons divalentes para exercer sua atividade hemaglutinante (AH. O objetivo neste trabalho foi estudar diferentes métodos de extração da lectina da farinha de folhas de mandioca (FFM e avaliar o efeito dos íons Ca2+ e Mn2+ para sua AH. Foram feitos testes de extração das proteínas utilizando dois extratores, água e solução salina (0,15 mol.L-1, pH 7,4, em quatro tempos de extração, 15, 60, 120 e 180 minutos. Para avaliar o efeito dos íons Ca2+ e Mn2+ na AH da lectina da FFM, o extrato proteico foi dialisado contra EDTA e a AH determinada. O efeito desses cátions na aglutinação de hemácias também foi avaliado isoladamente. O método de extração proteica usando água destilada como extrator por 15 minutos é o mais adequado. Não houve perda da AH na ausência dos íons. Os cátions Ca2+ (5 mmol.L-1, Mn2+ (1, 3 e 5 mmol.L-1 e a mistura de ambos nas mesmas concentrações provocam aglutinação de hemácias, na ausência de lectina.Lectins are carbohydrates binding proteins, capable of agglutinating erythrocytes, which can act as anti-nutritional factors. The isolation of these toxic proteins is interesting both for its anti- nutritional action and for its application in biotechnology. Some lectins need the presence of divalent ions to express hemagglutinating activity (AH. The objective of this work was to investigate different methods of extracting lectins from cassava leaf flour (CLF and to evaluate the effect of the ions Ca2+ and Mn2+ on the AH. Protein extraction tests were performed utilizing two extractors, water and saline solution (0.15 mol.L-1, NaCl pH 7.4, under four extraction times, 15, 60, 120, and 180 minutes

  20. MCL and mincle: C-type lectin receptors that sense damaged self and pathogen associated molecular patterns

    Directory of Open Access Journals (Sweden)

    Mark B Richardson

    2014-06-01

    Full Text Available MCL (macrophage C-type lectin and mincle (macrophage inducible C-type lectin comprise part of an extensive repertoire of pattern recognition receptors with the ability to sense damage associated and pathogen associated molecular patterns. In this review we cover the discovery and molecular characterization of these C-type lectin receptors, and highlight recent advances in the understanding of their roles in orchestrating the response of the immune system to bacterial and fungal infection, and damaged self. We also discuss the identification and structure-activity relationships of activating ligands, particularly trehalose dimycolate (TDM and related mycobacterial glycolipids, which have significant potential in the development of TH1/TH17 vaccination strategies.

  1. Lectin enhancement of the lipofection efficiency in human lung carcinoma cells.

    Science.gov (United States)

    Yanagihara, K; Cheng, P W

    1999-10-18

    Poor transfection efficiency of human lung carcinoma cells by lipofection begs further development of more efficient gene delivery strategies. The purpose of this study was to determine whether lectins can improve the lipofection efficiency in lung carcinoma cells. A549, Calu3, and H292 cells grown to 90% confluence were transfected for 18 h with a plasmid DNA containing a beta-galactosidase reporter gene (pCMVlacZ) using lipofectin plus a lectin as the vector. Ten different lectins, which exhibit a wide range of carbohydrate-binding specificities, were examined for their abilities to enhance the efficiency of lipofection. The transfected cells were assessed for transfection efficiency by beta-galactosidase activity (units/microg protein) and % blue cells following X-Gal stain. Lipofectin supplemented with Griffonia simplicifolia-I (GS-I) yields largest enhancement of the lipofection efficiency in A549 and Calu3 cells (5.3- and 28-fold, respectively). Maackia amurensis gives the largest enhancement (6.5-fold) of lipofection efficiency in H292 cells. The transfection efficiency correlates with the amounts of DNA delivered to the nucleus. Binding of FITC-labeled GS-I and the enhancement of the lipofection efficiency by GS-I were inhibited by alpha-methyl-D-galactopyranoside, indicating an alpha-galactoside-mediated gene transfer to lung carcinoma cells. We conclude that lectin-facilitated lipofection is an efficient gene delivery strategy. Employment of cell type-specific lectins may allow for efficient cell type-specific gene targeting.

  2. Identification of structural and secretory lectin-binding glycoproteins of normal and cancerous human prostate.

    Science.gov (United States)

    Lad, P M; Cooper, J F; Learn, D B; Olson, C V

    1984-12-07

    We have utilized the technique of lectin-loading of SDS gels with iodinated concanavalin A and wheat germ agglutinin to identify glycoproteins in prostatic and seminal fluids as well as in prostate tissue fractions. The following subunits which bound both lectins were detected: (a) 50, 43 and 38 kDa subunits common to prostatic and seminal fluids, and an additional 55 kDa subunit which predominates only in prostatic fluid; (b) 78, 55, 50 and 43 kDa subunits in prostatic tissue cytosol and (c) 195, 170, 135, 116 and 95 kDa subunits present in the particulate fractions of prostatic tissue. Immunoblotting using specific rabbit antibodies revealed the 50 kDa band to be prostatic acid phosphatase and the 38 kDa band to be prostate-specific antigen. Interestingly, antibodies directed toward prostatic acid phosphatase were found to cross-react with the 43 kDa band. Fractionation on sucrose gradients showed that several of these particulate glycoproteins were associated with a vesicle fraction enriched in adenylate cyclase activity, implying that they are plasma membrane glycoproteins. Comparison of soluble and particulate fractions of normal and cancerous tissue homogenates was made by densitometric scanning of autoradiograms of lectin-loaded gels. Similar relative intensities of lectin-binding were obtained for corresponding proteins in normal and cancerous tissue fractions. Also, immunoblotting showed no differences in prostatic acid phosphatase or prostate-specific antigen between normal and cancerous soluble homogenate fractions. Our results suggest that major lectin-binding proteins are conserved in the transition from normal to cancerous tissue. These results may be useful in developing a multiple-marker profile of metastatic prostate cancer and for the design of imaging agents, such as monoclonal antibodies, to prominent soluble and particulate prostate glycoproteins.

  3. The Complement C3a-C3aR Axis Promotes Development of Thoracic Aortic Dissection via Regulation of MMP2 Expression.

    Science.gov (United States)

    Ren, Weihong; Liu, Yan; Wang, Xuerui; Piao, Chunmei; Ma, Youcai; Qiu, Shulan; Jia, Lixin; Chen, Boya; Wang, Yuan; Jiang, Wenjian; Zheng, Shuai; Liu, Chang; Dai, Nan; Lan, Feng; Zhang, Hongjia; Song, Wen-Chao; Du, Jie

    2018-03-01

    Thoracic aortic dissection (TAD), once ruptured, is devastating to patients, and no effective pharmaceutical therapy is available. Anaphylatoxins released by complement activation are involved in a variety of diseases. However, the role of the complement system in TAD is unknown. We found that plasma levels of C3a, C4a, and C5a were significantly increased in patients with TAD. Elevated circulating C3a levels were also detected in the developmental process of mouse TAD, which was induced by β-aminopropionitrile monofumarate (BAPN) treatment, with enhanced expression of C1q and properdin in mouse dissected aortas. These findings indicated activation of classical and alternative complement pathways. Further, expression of C3aR was obviously increased in smooth muscle cells of human and mouse dissected aortas, and knockout of C3aR notably inhibited BAPN-induced formation and rupture of TAD in mice. C3aR antagonist administered pre- and post-BAPN treatment attenuated the development of TAD. We found that C3aR knockout decreased matrix metalloproteinase 2 (MMP2) expression in BAPN-treated mice. Additionally, recombinant C3a stimulation enhanced MMP2 expression and activation in smooth muscle cells that were subjected to mechanical stretch. Finally, we generated MMP2-knockdown mice by in vivo MMP2 short hairpin RNA delivery using recombinant adeno-associated virus and found that MMP2 deficiency significantly reduced the formation of TAD. Therefore, our study suggests that the C3a - C3aR axis contributes to the development of TAD via regulation of MMP2 expression. Targeting the C3a-C3aR axis may represent a strategy for inhibiting the formation of TAD. Copyright © 2018 by The American Association of Immunologists, Inc.

  4. Characterization of the okra mucilage by interaction with Gal, GalNAc and GlcNAc specific lectins.

    Science.gov (United States)

    Wu, A M; Jiang, Y J; Hwang, P Y; Shen, F S

    1995-02-23

    A bio-active polysaccharide, which was the major component of the extract of the common okra, Hibiscus esculentus, was isolated from the extract by precipitation with ethanol between 28.5 to 45%. According to a previous report (Whistler, R.L. and Conrad, H.E. (1954) J. Am. Chem. Soc. 76, 1673-1674), this polysaccharide contains the Gal alpha 1-->4Gal sequence, which is the ligand for the uropathogenic Escherichia coli and toxic lectins. Analysis of the binding property of the okra polysaccharide by precipitin assay with Gal, GalNAc and GlcNAc specific lectins showed that this okra mucilage reacted best with Mistletoe toxic lectin-I (ML-I) and precipitated over 80% of the ML-I nitrogen (5.1 micrograms N) added. It also precipitated well with Abrus precatorius (APA), Momordica charantia (MCA) and Ricinus communis (RCA1) agglutinins, but poorly with other lectins. The results obtained suggest that this polysaccharide is a valuable reagent to differentiate Gal specific lectins from the GalNAc and/or GlcNAc specific series.

  5. A simple procedure for the isolation of L-fucose-binding lectins from Ulex europaeus and Lotus tetragonolobus.

    Science.gov (United States)

    Allen, H J; Johnson, E A

    1977-10-01

    L-Fucose-binding lectins from Ulex europeaus and Lotus tetragonolobus were isolated by affinity chromatography on columns of L-fucose-Sepharose 6B. L-Fucose was coupled to Sepharose 6B after divinyl sulfone-activation of the gel to give an affinity adsorbent capable of binding more than 1.2 mg of Ulex lextin/ml of gel, which could then be eluted with 0.1M or 0.05M L-fucose. Analysis of the isolated lectins by hemagglutination assay, by gel filtration, and polyacrylamide disc-electrophoresis revealed the presence of isolectins, or aggregated species, or both. The apparent mol. wt. of the major lectin fraction from Lotus was 35000 when determined on Sephadex G-200 or Ultrogel AcA 34. In contrast, the apparent mol. wt. of the major lectin fraction from Ulex was 68 000 when chromatographed on Sephadex G-200 and 45 000 when chromatographed on Ultrogel AcA 34. The yields of lectins were 4.5 mg/100 g of Ulex seeds and 394 mg/100 g of Lotus seeds.

  6. The Climate Change Consortium of Wales (C3W)

    Science.gov (United States)

    Hendry, K. R.; Reis, J.; Hall, I. R.

    2011-12-01

    In response to the complexity and multidisciplinary nature of climate change research, the Climate Change Consortium of Wales (C3W) was formed in 2009 by the Welsh universities of Aberystwyth, Bangor, Cardiff and Swansea. Initially funded by Welsh Government, through the Higher Education Funding Council for Wales, the Countryside Council for Wales and the universities, C3W aims to bring together climate change researchers from a wide range of disciplines to explore scientific and sociological drivers, impacts and implications at local, national and international scale. The specific aims are to i) improve our fundamental understanding of the causes, nature, timing and consequences of climate change on Planet Earth's environment and on humanity, and ii) to reconfigure climate research in Wales as a recognisable centre of excellence on the world stage. In addition to improving the infrastructure for climate change research, we aim to improve communication, networking, collaborative research, and multidisciplinary data assimilation within and between the Welsh universities, and other UK and international institutions. Furthermore, C3W aims to apply its research by actively contributing towards national policy development, business development and formal and informal education activities within and beyond Wales.

  7. Complement-mediated neutralization of dengue virus requires mannose-binding lectin

    DEFF Research Database (Denmark)

    Avirutnan, Panisadee; Hauhart, Richard E; Marovich, Mary A

    2011-01-01

    -dependent activation of the complement cascade neutralized insect cell-derived West Nile virus (WNV) in cell culture and restricted pathogenesis in mice. Here, we investigated the antiviral activity of MBL in infection by dengue virus (DENV), a related flavivirus. Using a panel of naïve sera from mouse strains...... with lower levels. Our studies suggest that allelic variation of MBL in humans may impact complement-dependent control of DENV pathogenesis. IMPORTANCE Dengue virus (DENV) is a mosquito-transmitted virus that causes a spectrum of clinical disease in humans ranging from subclinical infection to dengue...... hemorrhagic fever and dengue shock syndrome. Four serotypes of DENV exist, and severe illness is usually associated with secondary infection by a different serotype. Here, we show that mannose-binding lectin (MBL), a pattern recognition molecule that initiates the lectin pathway of complement activation...

  8. Engineering of PA-IIL lectin from Pseudomonas aeruginosa – Unravelling the role of the specificity loop for sugar preference

    Directory of Open Access Journals (Sweden)

    Imberty Anne

    2007-06-01

    Full Text Available Abstract Background Lectins are proteins of non-immune origin capable of binding saccharide structures with high specificity and affinity. Considering the high encoding capacity of oligosaccharides, this makes lectins important for adhesion and recognition. The present study is devoted to the PA-IIL lectin from Pseudomonas aeruginosa, an opportunistic human pathogen capable of causing lethal complications in cystic fibrosis patients. The lectin may play an important role in the process of virulence, recognizing specific saccharide structures and subsequently allowing the bacteria to adhere to the host cells. It displays high values of affinity towards monosaccharides, especially fucose – a feature caused by unusual binding mode, where two calcium ions participate in the interaction with saccharide. Investigating and understanding the nature of lectin-saccharide interactions holds a great potential of use in the field of drug design, namely the targeting and delivery of active compounds to the proper site of action. Results In vitro site-directed mutagenesis of the PA-IIL lectin yielded three single point mutants that were investigated both structurally (by X-ray crystallography and functionally (by isothermal titration calorimetry. The mutated amino acids (22–23–24 triad belong to the so-called specificity binding loop responsible for the monosaccharide specificity of the lectin. The mutation of the amino acids resulted in changes to the thermodynamic behaviour of the mutants and subsequently in their relative preference towards monosaccharides. Correlation of the measured data with X-ray structures provided the molecular basis for rationalizing the affinity changes. The mutations either prevent certain interactions to be formed or allow formation of new interactions – both of afore mentioned have strong effects on the saccharide preferences. Conclusion Mutagenesis of amino acids forming the specificity binding loop allowed

  9. Current status of lectin-based cancer diagnosis and therapy

    Directory of Open Access Journals (Sweden)

    Fohona S. Coulibaly

    2017-01-01

    Full Text Available Lectins are carbohydrate recognizing proteins originating from diverse origins in nature, including animals, plants, viruses, bacteria and fungus. Due to their exceptional glycan recognition property, they have found many applications in analytical chemistry, biotechnology and surface chemistry. This manuscript explores the current use of lectins for cancer diagnosis and therapy. Moreover, novel drug delivery strategies aiming at improving lectin’s stability, reducing their undesired toxicity and controlling their non-specific binding interactions are discussed. We also explore the nanotechnology application of lectins for cancer targeting and imaging. Although many investigations are being conducted in the field of lectinology, there is still a limited clinical translation of the major findings reported due to lectins stability and toxicity concerns. Therefore, new investigations of safe and effective drug delivery system strategies for lectins are warranted in order to take full advantage of these proteins.

  10. Complement C3 gene: Expression characterization and innate immune response in razor clam Sinonovacula constricta.

    Science.gov (United States)

    Peng, Maoxiao; Niu, Donghong; Wang, Fei; Chen, Zhiyi; Li, Jiale

    2016-08-01

    Complement component 3 (C3) is central to the complement system, playing an important role in immune defense, immune regulation and immune pathology. Several C3 genes have been characterized in invertebrates but very few in shellfish. The C3 gene was identified from the razor clam Sinonovacula constricta, referred to here as Sc-C3. It was found to be highly homologous with the C3 gene of Ruditapes decussatus. All eight model motifs of the C3 gene were found to be included in the thiolester bond and the C345C region. Sc-C3 was widely expressed in all healthy tissues with expression being highest in hemolymph. A significant difference in expression was revealed at the umbo larvae development stage. The expression of Sc-C3 was highly regulated in the hemolymph and liver, with a distinct response pattern being noted after a challenge with Micrococcus lysodeikticus and Vibrio parahemolyticus. It is therefore suggested that a complicated and unique response pathway may be present in S. constricta. Further, serum of S. constricta containing Sc-C3 was extracted. This was activated by LPS or bacterium for verification for function. The more obvious immune function of Sc-C3 was described as an effective membrane rupture in hemocyte cells of rabbit, V. parahemolyticus and Vibrio anguillarum. Thus, Sc-C3 plays an essential role in the immune defense of S. constricta. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Glycoprofiling of Early Gastric Cancer Using Lectin Microarray Technology.

    Science.gov (United States)

    Li, Taijie; Mo, Cuiju; Qin, Xue; Li, Shan; Liu, Yinkun; Liu, Zhiming

    2018-01-01

    Recently, studies have reported that protein glycosylation plays an important role in the occurrence and development of cancer. Gastric cancer is a common cancer with high morbidity and mortality owing to most gastric cancers are discovered only at an advanced stage. Here, we aim to discover novel specific serum glycanbased biomarkers for gastric cancer. A lectin microarray with 50 kinds of tumor-associated lectin was used to detect the glycan profiles of serum samples between early gastric cancer and healthy controls. Then lectin blot was performed to validate the differences. The result of the lectin microarray showed that the signal intensities of 13 lectins showed significant differences between the healthy controls and early gastric cancer. Compared to the healthy, the normalized fluorescent intensities of the lectins PWA, LEL, and STL were significantly increased, and it implied that their specifically recognized GlcNAc showed an especially elevated expression in early gastric cancer. Moreover, the binding affinity of the lectins EEL, RCA-II, RCA-I, VAL, DSA, PHA-L, UEA, and CAL were higher in the early gastric cancer than in healthy controls. These glycan structures containing GalNAc, terminal Galβ 1-4 GlcNAc, Tri/tetraantennary N-glycan, β-1, 6GlcNAc branching structure, α-linked fucose residues, and Tn antigen were elevated in gastric cancer. While the two lectins CFL GNL reduced their binding ability. In addition, their specifically recognized N-acetyl-D-galactosamine structure and (α-1,3) mannose residues were decreased in early gastric cancer. Furthermore, lectin blot results of LEL, STL, PHA-L, RCA-I were consistent with the results of the lectin microarray. The findings of our study clarify the specific alterations for glycosylation during the pathogenesis of gastric cancer. The specific high expression of GlcNAc structure may act as a potential early diagnostic marker for gastric cancer.

  12. Effects of Lectins on initial attachment of cariogenic Streptococcus mutans.

    Science.gov (United States)

    Ito, Takashi; Yoshida, Yasuhiro; Shiota, Yasuyoshi; Ito, Yuki; Yamamoto, Tadashi; Takashiba, Shogo

    2018-02-01

    Oral bacteria initiate biofilm formation by attaching to tooth surfaces via an interaction of a lectin-like bacterial protein with carbohydrate chains on the pellicle. This study aimed to find naturally derived lectins that inhibit the initial attachment of a cariogenic bacterial species, Streptococcus mutans (S. mutans), to carbohydrate chains in saliva in vitro. Seventy kinds of lectins were screened for candidate motifs that inhibit the attachment of S. mutans ATCC 25175 to a saliva-coated culture plate. The inhibitory effect of the lectins on attachment of the S. mutans to the plates was quantified by crystal violet staining, and the biofilm was observed under a scanning electron microscope (SEM). Surface plasmon resonance (SPR) analysis was performed to examine the binding of S. mutans to carbohydrate chains and the binding of candidate lectins to carbohydrate chains, respectively. Moreover, binding assay between the biotinylated-lectins and the saliva components was conducted to measure the lectin binding. Lectins recognizing a salivary carbohydrate chain, Galβ1-3GalNAc, inhibited the binding of S. mutans to the plate. In particular, Agaricus bisporus agglutinin (ABA) markedly inhibited the binding. This inhibition was confirmed by SEM observation. SPR analysis indicated that S. mutans strongly binds to Galβ1-3GalNAc, and ABA binds to Galβ1-3GalNAc. Finally, the biotinylated Galβ1-3GalNAc-binding lectins including ABA demonstrated marked binding to the saliva components. These results suggest that ABA lectin inhibited the attachment of S. mutans to Galβ1-3GalNAc in saliva and ABA can be useful as a potent inhibitor for initial attachment of oral bacteria and biofilm formation.

  13. Lectin Complement Pathway Proteins in Healthy Individuals

    DEFF Research Database (Denmark)

    Troldborg, Anne; Hansen, Annette Gudmann; Hansen, Søren W K

    2017-01-01

    , it is pivotal to know the normal. Our aim was to describe the concentrations of the eleven known proteins of the lectin pathway in serum and plasma and to uncover possible gender differences, age and diurnal variations, which must be taken into account for investigations in different cohorts. We examined...... morning to the middle of night. There were gender differences for most proteins, whereas age did not seem to influence concentration. The present study underlines the necessity of considering which material to use, correct matching and a trial design that takes the nature of the protein into account...

  14. Glycan microarray analysis of the carbohydrate-recognition specificity of native and recombinant forms of the lectin ArtinM.

    Science.gov (United States)

    Liu, Y; Cecílio, N T; Carvalho, F C; Roque-Barreira, M C; Feizi, T

    2015-12-01

    This article contains data related to the researc.h article entitled "Yeast-derived ArtinM shares structure, carbohydrate recognition, and biological effects with native ArtinM" by Cecílio et al. (2015) [1]. ArtinM, a D-mannose-binding lectin isolated from the seeds of Artocarpus heterophyllus, exerts immunomodulatory and regenerative activities through its Carbohydrate Recognition Domain (CRD) (Souza et al., 2013; Mariano et al., 2014 [2], [3]). The limited availability of the native lectin (n-ArtinM) led us to characterize a recombinant form of the protein, obtained by expression in Saccharomyces cerevisiae (y-ArtinM). We compared the carbohydrate-binding specificities of y-ArtinM and n-ArtinM by analyzing the binding of biotinylated preparations of the two lectin forms using a neoglycolipid (NGL)-based glycan microarray. Data showed that y-ArtinM mirrored the specificity exhibited by n-ArtinM.

  15. Dynamic interplay between catalytic and lectin domains of GalNAc-transferases modulates protein O-glycosylation

    DEFF Research Database (Denmark)

    Lira-Navarrete, Erandi; de Las Rivas, Matilde; Compañón, Ismael

    2015-01-01

    the first crystal structures of complexes of GalNAc-T2 with glycopeptides that together with enhanced sampling molecular dynamics simulations demonstrate a cooperative mechanism by which the lectin domain enables free acceptor sites binding of glycopeptides into the catalytic domain. Atomic force microscopy......Protein O-glycosylation is controlled by polypeptide GalNAc-transferases (GalNAc-Ts) that uniquely feature both a catalytic and lectin domain. The underlying molecular basis of how the lectin domains of GalNAc-Ts contribute to glycopeptide specificity and catalysis remains unclear. Here we present...... and small-angle X-ray scattering experiments further reveal a dynamic conformational landscape of GalNAc-T2 and a prominent role of compact structures that are both required for efficient catalysis. Our model indicates that the activity profile of GalNAc-T2 is dictated by conformational heterogeneity...

  16. Identification of the site of human mannan-binding lectin involved in the interaction with its partner serine proteases: the essential role of Lys55

    DEFF Research Database (Denmark)

    Teillet, F; Lacroix, M; Thiel, Steffen

    2007-01-01

    Mannan-binding lectin (MBL) is an oligomeric lectin that binds neutral carbohydrates on pathogens, forms complexes with MBL-associated serine proteases (MASP)-1, -2, and -3 and 19-kDa MBL-associated protein (MAp19), and triggers the complement lectin pathway through activation of MASP-2. To ident......Mannan-binding lectin (MBL) is an oligomeric lectin that binds neutral carbohydrates on pathogens, forms complexes with MBL-associated serine proteases (MASP)-1, -2, and -3 and 19-kDa MBL-associated protein (MAp19), and triggers the complement lectin pathway through activation of MASP-2....... To identify the MASP binding site(s) of human MBL, point mutants targeting residues C-terminal to the hinge region were produced and tested for their interaction with the MASPs and MAp19 using surface plasmon resonance and functional assays. Mutation Lys(55)Ala abolished interaction with the MASPs and MAp19...... and prevented formation of functional MBL-MASP-2 complexes. Mutations Lys(55)Gln and Lys(55)Glu abolished binding to MASP-1 and -3 and strongly inhibited interaction with MAp19. Conversely, mutation Lys(55)Arg abolished interaction with MASP-2 and MAp19, but only weakened interaction with MASP-1 and -3...

  17. S-25-hydroxyvitamin D and C3-epimers in pregnancy and infancy

    DEFF Research Database (Denmark)

    Dreier Mydtskov, Nanne; Lykkedegn, Sine; Fruekilde, Palle Back Nielsen

    2017-01-01

    BACKGROUND: Analysis of serum 25-hydroxyvitamin D (s-25(OH)D) may be complicated by the less active or in-active vitamin D metabolite C3-epi-25(OH)D3 (C3-epimer). We aimed to explore the relationship between s-C3-epimer and s-25(OH)D and other determinants and describe the longitudinal course of ...... correlated to s-25(OH)D, season, maternal vitamin D supplementation, maternal and infant age. The C3-epimer fraction was only of clinical importance in early infancy, where it could lead to misclassification of the vitamin D status.......BACKGROUND: Analysis of serum 25-hydroxyvitamin D (s-25(OH)D) may be complicated by the less active or in-active vitamin D metabolite C3-epi-25(OH)D3 (C3-epimer). We aimed to explore the relationship between s-C3-epimer and s-25(OH)D and other determinants and describe the longitudinal course...... correlated with s-25(OH)D (all time points, pvitamin D supplementation at some time points. The C3-epimer fraction fluctuated between adjacent time points. By cosinor analyses, a season-dependent sinusoidal pattern for s-25(OH)D and C3-epimer fraction...

  18. Microgramma vacciniifolia (Polypodiaceae) fronds contain a multifunctional lectin with immunomodulatory properties on human cells.

    Science.gov (United States)

    de Siqueira Patriota, Leydianne Leite; Procópio, Thamara Figueiredo; de Santana Brito, Jéssica; Sebag, Virginie; de Oliveira, Ana Patrícia Silva; de Araújo Soares, Ana Karine; Moreira, Leyllane Rafael; de Albuquerque Lima, Thâmarah; Soares, Tatiana; da Silva, Túlio Diego; Paiva, Patrícia Maria Guedes; de Lorena, Virgínia Maria Barros; de Melo, Cristiane Moutinho Lagos; de Albuquerque, Lidiane Pereira; Napoleão, Thiago Henrique

    2017-10-01

    In this study, we report the purification and characterization of a multifunctional lectin (MvFL) from Microgramma vacciniifolia fronds as well as its immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). MvFL (pI 4.51; 54kDa) is a glycoprotein able to inhibit trypsin activity and that has sequence similarities (32% coverage) with a plant RNA-binding protein. Hemagglutinating activity of MvFL was not altered by heating at 100°C for 30min, but was reduced in alkaline pH (8.0 and 9.0). Fluorimetric analyses showed that this lectin did not undergo marked conformational changes when heated. However, the MvFL conformation changed depending on the pH. MvFL at 6.25-25μg/mL was not cytotoxic to lymphocytes present among PBMCs. The PBMCs incubated for 24h with the lectin (12.5μg/mL) showed increased TNF-α, IFN-γ, IL-6, IL-10, and nitric oxide production. MvFL also stimulated T lymphocytes from PBMCs to differentiate into CD8 + cells. The activation (indicated by CD28 expression) of these cells was also stimulated. In conclusion, MvFL is a heat-stable and multifunctional protein, with both lectin and trypsin inhibitor activities, and capable of inducing predominantly a Th1 response in human PBMCs as well as activation and differentiation of T lymphocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Extrinsic functions of lectin domains in O-N-acetylgalactosamine glycan biosynthesis

    DEFF Research Database (Denmark)

    Lorenz, Virginia; Ditamo, Yanina; Cejas, Romina B

    2016-01-01

    during O-GalNAc glycan biosynthesis. The presence of lectin domain T3lec or T4lec during ppGalNAc-T2 and ppGalNAc-T3 catalytic reaction had a clear inhibitory effect on GalNAc-T activity. Interaction of T3lec or T4lec with ppGalNAc-T2 catalytic domain was not mediated by carbohydrate. T3lec, but not T2......Glycan biosynthesis occurs mainly in Golgi. Molecular organization and functional regulation of this process are not well understood. We evaluated the extrinsic effect of lectin domains (β-trefoil fold) of polypeptide GalNAc-transferases (ppGalNAc-Ts) on catalytic activity of glycosyltransferases...

  20. Exposure to chronic hyperglycemic conditions results in Ras-related C3 botulinum toxin substrate 1 (Rac1)-mediated activation of p53 and ATM kinase in pancreatic β-cells.

    Science.gov (United States)

    Sidarala, Vaibhav; Kowluru, Anjaneyulu

    2017-05-01

    Chronic hyperglycemia (HG) promotes pancreatic islet dysfunction which leads to the onset of T2DM. This study is aimed at defining regulatory roles of Rac1, a small G-protein, in the activation of p53 and ATM kinase in pancreatic β-cells, under the duress of HG conditions. We report significant stimulatory effects of HG (20 mM; 24 h) on p53 activation in INS-1 832/13 cells, normal rodent and human islets. Pharmacological inhibition of Rac1 (EHT1864 or NSC23766) significantly suppressed HG-induced p53 activation in INS-1 832/13 cells and rat islets, suggesting novel roles for this small G-protein in the activation of p53. Inhibition of Rac1 geranylgeranylation with simvastatin or GGTI-2147, significantly attenuated HG-induced p53 activation, suggesting requisite roles for this signaling step in HG-mediated effects on β-cells. HG-induced p53 activation was also suppressed by SB203580, a known inhibitor of p38MAPK. Additionally, we observed increased activation of ATM kinase under HG conditions, which was blocked in presence of EHT1864. Furthermore, pharmacological inhibition of ATM kinase (KU55933) reduced activation of ATM kinase, but not p53, suggesting that HG-mediated activation of p53 and ATM could represent independent pro-apoptotic events. In conclusion, these data indicate that sustained activation of Rac1-p38MAPK signaling axis leads to activation of p53 leading to β-cell dysfunction under the duress of chronic hyperglycemic conditions.

  1. Determination of the Proportion of Total Soil Extracellular Acid Phosphomonoesterase (E.C. 3.1.3.2 Activity Represented by Roots in the Soil of Different Forest Ecosystems

    Directory of Open Access Journals (Sweden)

    Klement Rejsek

    2012-01-01

    Full Text Available The aim of this study is to present a new method for determining the root-derived extracellular acid phosphomonoesterase (EAPM activity fraction within the total EAPM activity of soil. EAPM activity was determined for roots, organic and mineral soil. Samples were collected using paired PVC cylinders, inserted to a depth of 15 cm, within seven selected forest stands. Root-derived EAPM formed between 4 and18% of the total EAPM activity of soil from forests of differing maturity. A new approach, presented in this work, enables separation of root-derived EAPM activity from total soil EAPM. Separation of root-derived EAPM from soil provides a better understanding of its role in P-cycling in terrestrial ecosystems. The method presented in this work is a first step towards the separation of root- and microbe-derived EAPM in soils, which are thought to possess different kinetic properties and different sensitivity to environmental change.

  2. A novel antihuman C3d monoclonal antibody with specificity to the C3d complement split product

    DEFF Research Database (Denmark)

    Rasmussen, Karina Juhl; Skjødt, Mikkel-Ole; Vitved, Lars

    2017-01-01

    The complement component C3 and the cleavage products of C3b/iC3b, C3c and C3d are used as biomarkers in clinical diagnostics. Currently, no specific antibodies are able to differentiate C3d from other fragments, although such a distinction could be very valuable considering that they may reflect...... different pathophysiological mechanisms. We have developed a rat antihuman C3d monoclonal antibody with specificity to the end sequence of the N-terminal region of C3d. The antibody can therefore only bind to C3d when it manifests itself as the final end product of cleaved C3. We believe...

  3. Mannose-binding Lectin and the Risk of HIV Transmission and Disease Progression in Children A Systematic Review

    NARCIS (Netherlands)

    Israëls, Joël; Scherpbier, Henriette J.; Frakking, Florine N. J.; van de Wetering, Marianne D.; Kremer, Leontien C. M.; Kuijpers, Taco W.

    2012-01-01

    Background: Mannose-binding lectin (MBL) can activate the complement system by binding to carbohydrates, such as those presented on the HIV virion surface. It is unclear whether genetically determined MBL deficiency is related to vertical HIV transmission and disease progression in HIV-infected

  4. Glucotoxicity promotes aberrant activation and mislocalization of Ras-related C3 botulinum toxin substrate 1 [Rac1] and metabolic dysfunction in pancreatic islet β-cells: reversal of such metabolic defects by metformin.

    Science.gov (United States)

    Baidwan, Sartaj; Chekuri, Anil; Hynds, DiAnna L; Kowluru, Anjaneyulu

    2017-11-01

    Emerging evidence suggests that long-term exposure of insulin-secreting pancreatic β-cells to hyperglycemic (HG; glucotoxic) conditions promotes oxidative stress, which, in turn, leads to stress kinase activation, mitochondrial dysfunction, loss of nuclear structure and integrity and cell apoptosis. Original observations from our laboratory have proposed that Rac1 plays a key regulatory role in the generation of oxidative stress and downstream signaling events culminating in the onset of dysfunction of pancreatic β-cells under the duress of metabolic stress. However, precise molecular and cellular mechanisms underlying the metabolic roles of hyperactive Rac1 remain less understood. Using pharmacological and molecular biological approaches, we now report mistargetting of biologically-active Rac1 [GTP-bound conformation] to the nuclear compartment in clonal INS-1 cells, normal rat islets and human islets under HG conditions. Our findings also suggest that such a signaling step is independent of post-translational prenylation of Rac1. Evidence is also presented to highlight novel roles for sustained activation of Rac1 in HG-induced expression of Cluster of Differentiation 36 [CD36], a fatty acid transporter protein, which is implicated in cell apoptosis. Finally, our findings suggest that metformin, a biguanide anti-diabetic drug, at a clinically relevant concentration, prevents β-cell defects [Rac1 activation, nuclear association, CD36 expression, stress kinase and caspase-3 activation, and loss in metabolic viability] under the duress of glucotoxicity. Potential implications of these findings in the context of novel and direct regulation of islet β-cell function by metformin are discussed.

  5. Composition of extracts of airborne grain dusts: lectins and lymphocyte mitogens.

    Science.gov (United States)

    Olenchock, S A; Lewis, D M; Mull, J C

    1986-01-01

    Airborne grain dusts are heterogeneous materials that can elicit acute and chronic respiratory pathophysiology in exposed workers. Previous characterizations of the dusts include the identification of viable microbial contaminants, mycotoxins, and endotoxins. We provide information on the lectin-like activity of grain dust extracts and its possible biological relationship. Hemagglutination of erythrocytes and immunochemical modulation by antibody to specific lectins showed the presence of these substances in extracts of airborne dusts from barley, corn, and rye. Proliferation of normal rat splenic lymphocytes in vitro provided evidence for direct biological effects on the cells of the immune system. These data expand the knowledge of the composition of grain dusts (extracts), and suggest possible mechanisms that may contribute to respiratory disease in grain workers. PMID:3709474

  6. Eculizumab treatment: stochastic occurrence of C3 binding to individual PNH erythrocytes

    Directory of Open Access Journals (Sweden)

    Michela Sica

    2017-06-01

    Full Text Available Abstract Background C5 blockade by eculizumab prevents complement-mediated intravascular hemolysis in paroxysmal nocturnal hemoglobinuria (PNH. However, C3-bound PNH red blood cells (RBCs, arising in almost all treated patients, may undergo extravascular hemolysis reducing clinical benefits. Despite the uniform deficiency of CD55 and of CD59, there are always two distinct populations of PNH RBCs, with (C3+ and without (C3C3 binding. Methods To investigate this paradox, the phenomenon has been modeled in vitro by incubating RBCs from eculizumab untreated PNH patients with compatible sera containing eculizumab, and by assessing the C3 binding after activation of complement alternative pathway. Results When RBCs from untreated patients were exposed in vitro to activated complement in the context of C5-blockade, there was the prompt appearance of a distinct C3+ PNH RBC population whose size increased with time and also with the rate of complement activation. Eventually, all PNH RBCs become C3+ to the same extent, without differences between old and young (reticulocytes PNH RBCs. Conclusions This study indicates that the distinct (C3+ and C3− PNH RBC populations are not intrinsically different; rather, they result from a stochastic all-or-nothing phenomenon linked to the time-dependent cumulative probability of each individual PNH red cell to be exposed to levels of complement activation able to trigger C3 binding. These findings may envision novel approaches to reduce C3 opsonization and the subsequent extravascular hemolysis in PNH patients on eculizumab.

  7. Protective Role of Complement C3 Against Cytokine-Mediated beta-Cell Apoptosis

    DEFF Research Database (Denmark)

    Dos Santos, Reinaldo S.; Marroqui, Laura; Grieco, Fabio A.

    2017-01-01

    silencing exacerbates apoptosis under both basal condition and following exposure to cytokines, and it increases chemokine expression upon cytokine treatment. C3 exerts its prosurvival effects via AKT activation and c-Jun N-terminal kinase inhibition. Exogenously added C3 also protects against cytokine...

  8. Final Hazard Categorization for the Remediation of the 116-C-3 Chemical Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Blakley; W. D. Schofield

    2007-09-10

    This final hazard categorization (FHC) document examines the hazards, identifies appropriate controls to manage the hazards, and documents the commitments for the 116-C-3 Chemical Waste Tanks Remediation Project. The remediation activities analyzed in this FHC are based on recommended treatment and disposal alternatives described in the Engineering Evaluation for the Remediation to the 116-C-3 Chemical Waste Tanks (BHI 2005e).

  9. The immunomodulatory effect of plant lectins: a review with emphasis on ArtinM properties.

    Science.gov (United States)

    Souza, Maria A; Carvalho, Fernanda C; Ruas, Luciana P; Ricci-Azevedo, Rafael; Roque-Barreira, Maria Cristina

    2013-10-01

    Advances in the glycobiology and immunology fields have provided many insights into the role of carbohydrate-protein interactions in the immune system. We aim to present a comprehensive review of the effects that some plant lectins exert as immunomodulatory agents, showing that they are able to positively modify the immune response to certain pathological conditions, such as cancer and infections. The present review comprises four main themes: (1) an overview of plant lectins that exert immunomodulatory effects and the mechanisms accounting for these activities; (2) general characteristics of the immunomodulatory lectin ArtinM from the seeds of Artocarpus heterophyllus; (3) activation of innate immunity cells by ArtinM and consequent induction of Th1 immunity; (4) resistance conferred by ArtinM administration in infections with intracellular pathogens, such as Leishmania (Leishmania) major, Leishmania (Leishmania) amazonensis, and Paracoccidioides brasiliensis. We believe that this review will be a valuable resource for more studies in this relatively neglected area of research, which has the potential to reveal carbohydrate targets for novel prophylactic and therapeutic strategies.

  10. Crotacetin, a novel snake venom C-type lectin, is homolog of convulxin

    Directory of Open Access Journals (Sweden)

    G. Rádis-Baptista

    2005-12-01

    Full Text Available Snake venom (sv C-type lectins encompass a group of hemorrhagic toxins, which are able to interfere with hemostasis. They share significant similarity in their primary structures with C-type lectins of other animals, and also present a conserved carbohydrate recognition domain (CRD. A very well studied sv C-type lectin is the heterodimeric toxin, convulxin (CVX, from the venoms of South American rattlesnakes, Crotalus durissus terrificus and C. d. cascavella. It consists of two subunits, alfa (CVXalpha , 13.9 kDa and beta (CVXbeta , 12.6 kDa, joined by inter and intra-chain disulfide bounds, and is arranged in a tetrameric alpha4beta4 conformation. Convulxin is able to activate platelet and induce their aggregation by acting via p62/GPVI collagen receptor. Several cDNA precursors, homolog of CVX subunits, were cloned by PCR homology screening. As determined by computational analysis, one of them, named crotacetin beta subunit, was predicted as a polypeptide with a tridimensional conformation very similar to other subunits of convulxin-like snake toxins. Crotacetin was purified from C. durissus venoms by gel permeation and reverse phase high performance liquid chromatography. The heterodimeric crotacetin is expressed in the venoms of several C. durissus subspecies, but it is prevalent in the venom of C. durissus cascavella. As inferred from homology modeling, crotacetin induces platelet aggregation but noticeably exhibits antimicrobial activity against Gram-positive and Gram-negative bacteria.

  11. Immunomodulatory response of mice splenocytes induced by RcaL, a lectin isolated from cobia fish (Rachycentron canadum) serum.

    Science.gov (United States)

    Coriolano, Marília Cavalcanti; Silva, Cynarha Daysy Cardoso da; Melo, Cristiane Moutinho Lagos de; Bezerra, Ranilson de Souza; Santos, Athiê Jorge Guerra; Pereira, Valéria Rêgo Alves; Coelho, Luana Cassandra Breitenbach Barroso

    2012-11-01

    This work reports the isolation of a serum lectin from cobia fish (Rachycentron canadum) named RcaL. Immunomodulatory activity on mice splenocyte experimental cultures through cytotoxic assays and cytokine production were also performed. RcaL was obtained through precipitation with ammonium sulphate and affinity chromatography on a Concanavalin A-Sepharose 4B column. The ammonium sulphate fraction F3 showed the highest specific hemagglutinating activity and was applied to affinity chromatography. The lectin was eluted with methyl-α-D-mannopyranoside. RcaL showed highest affinity for methyl-α-D-mannopyranoside and D-mannose; eluted fractions of RcaL agglutinated rabbit erythrocytes (titre, 128(-1)) retained 66 % of chromatographed lectin activity, and the obtained purification factor was 1.14. Under reducing conditions, a polypeptide band of 19.2 kDa was revealed in sodium dodecyl sulphate polyacrylamide gel electrophoresis (PAGE). PAGE confirmed RcaL as an acidic protein revealed in a single band. Cytotoxic and immunomodulatory assays with RcaL in mice splenocyte cultures showed that the lectin was not cytotoxic and induced higher interferon gamma and nitric oxide production in splenocyte cultures. Purified RcaL induced preferential Th1 response, suggesting that it acts as an immunomodulatory compound.

  12. Improving g-C3N4 photocatalysis for NOx removal by Ag nanoparticles decoration

    International Nuclear Information System (INIS)

    Sun, Yanjuan; Xiong, Ting; Ni, Zilin; Liu, Jie; Dong, Fan; Zhang, Wei; Ho, Wing-Kei

    2015-01-01

    Graphical abstract: Ag/g-C 3 N 4 nanocomposites were prepared via a facile method for enhanced photocatalytic NO x removal due to surface plasmon resonance of Ag. - Highlights: • The Ag/g-C 3 N 4 nanocomposites were prepared using urea as the precursor. • The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air. • The Ag nanoparticles enhanced the photocatalytic activity of g-C 3 N 4 . • The surface plasmon resonance of Ag played a key role in photocatalysis. - Abstract: In order to overcome the intrinsic drawback of pristine g-C 3 N 4 , we prepared g-C 3 N 4 nanosheets with enhanced photocatalytic performance by Ag nanoparticles decoration using urea as the precursor. It was revealed that the monodispersed Ag nanoparticles were deposited on the surface of g-C 3 N 4 nanosheets. The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air under visible light irradiation. The results showed that the decoration of Ag nanoparticles not only enhanced the photocatalytic activity of g-C 3 N 4 nanosheets, but also benefited the oxidation of NO to final products. The increased visible light absorption arising from the surface plasmon resonance of Ag and improved separation and transfer of photoinduced carriers over Ag/g-C 3 N 4 composites were demonstrated by the UV–vis diffuse reflectance spectra and photoluminescence spectra, respectively. It was therefore proposed that the enhanced photocatalytic activity of Ag/g-C 3 N 4 composites could be attributed to the extended light response range and enhanced charge separation due to the introduction of Ag nanoparticles.

  13. Defining the complement biomarker profile of c3 glomerulopathy

    DEFF Research Database (Denmark)

    Zhang, Yuzhou; Nester, Carla M; Martin, Bertha

    2014-01-01

    BACKGROUND AND OBJECTIVES: C3 glomerulopathy (C3G) applies to a group of renal diseases defined by a specific renal biopsy finding: a dominant pattern of C3 fragment deposition on immunofluorescence. The primary pathogenic mechanism involves abnormal control of the alternative complement pathway......, although a full description of the disease spectrum remains to be determined. This study sought to validate and define the association of complement dysregulation with C3G and to determine whether specific complement pathway abnormalities could inform disease definition. DESIGN, SETTING, PARTICIPANTS......, & MEASUREMENTS: This study included 34 patients with C3G (17 with C3 glomerulonephritis [C3GN] and 17 with dense deposit disease [DDD]) diagnosed between 2008 and 2013 selected from the C3G Registry. Control samples (n=100) were recruited from regional blood drives. Nineteen complement biomarkers were assayed...

  14. C-Type Lectin Receptors in Asthma

    Directory of Open Access Journals (Sweden)

    Sabelo Hadebe

    2018-04-01

    Full Text Available Asthma is a heterogeneous disease that affects approximately 300 million people worldwide, largely in developed countries. The etiology of the disease is poorly understood, but is likely to involve specific innate and adaptive responses to inhaled microbial components that are found in allergens. Fungal-derived allergens represent a major contributing factor in the initiation, persistence, exacerbation, and severity of allergic asthma. C-type lectin like receptors, such as dectin-1, dectin-2, DC-specific intercellular adhesion molecule 3-grabbing nonintegrin, and mannose receptor, recognize many fungal-derived allergens and other structurally similar allergens derived from house dust mites (HDM. In some cases, the fungal derived allergens have been structurally and functionally identified alongside their respective receptors in both humans and mice. In this review, we discuss recent understanding on how selected fungal and HDM derived allergens as well as their known or unknown receptors shape allergic airway diseases.

  15. Crystallization of Ulex europaeus lectin I.

    Science.gov (United States)

    Vandonselaar, M; Delbaere, L T

    1994-10-21

    The lectin I from Ulex europaeus (UEAI) has a strong affinity for the H-type 2 human blood group determinant. Single crystals of UEAI have been grown in the monoclinic crystal system. Initial crystals were obtained after 11 months from a solution of 10 mg/ml protein, 40% 2,4-methylpentanediol and 0.1 N acetate buffer at pH 5.2. The technique of washing and reseeding was used to generate large suitable crystals. The space group is C2 with a = 78.84 A, b = 69.85 A, c = 120.62 A, beta = 108.74 degrees and Z = 4; there is one molecular dimer per asymmetric unit and the solvent content is estimated to be 58%. The crystals diffract to at least 2.8 A d spacings and are stable in the X-ray beam for more than three days.

  16. Genetics Home Reference: mannose-binding lectin deficiency

    Science.gov (United States)

    ... and Caregivers: Complement System Nobelprize.org: The Immune System - In More Detail Patient ... Sources for This Page Arora M, Munoz E, Tenner AJ. Identification of a site on mannan-binding lectin critical ...

  17. Human Lectins and Their Roles in Viral Infections

    Directory of Open Access Journals (Sweden)

    Christopher P. Mason

    2015-01-01

    Full Text Available Innate recognition of virus proteins is an important component of the immune response to viral pathogens. A component of this immune recognition is the family of lectins; pattern recognition receptors (PRRs that recognise viral pathogen-associated molecular patterns (PAMPs including viral glycoproteins. In this review we discuss the contribution of soluble and membrane-associated PRRs to immunity against virus pathogens, and the potential role of these molecules in facilitating virus replication. These processes are illustrated with examples of viruses including human immunodeficiency virus (HIV, hepatitis C virus (HCV and Ebola virus (EBOV. We focus on the structure, function and genetics of the well-characterised C-type lectin mannose-binding lectin, the ficolins, and the membrane-bound CD209 proteins expressed on dendritic cells. The potential for lectin-based antiviral therapies is also discussed.

  18. Lectins stain cells differentially in the coral, Montipora capitata

    Science.gov (United States)

    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.

  19. A Lectin from Dioclea violacea Interacts with Midgut Surface of Lutzomyia migonei, Unlike Its Homologues, Cratylia floribunda Lectin and Canavalia gladiata Lectin

    Directory of Open Access Journals (Sweden)

    Juliana Montezuma Barbosa Monteiro Tínel

    2014-01-01

    Full Text Available Leishmaniasis is a vector-borne disease transmitted by phlebotomine sand fly. Susceptibility and refractoriness to Leishmania depend on the outcome of multiple interactions that take place within the sand fly gut. Promastigote attachment to sand fly midgut epithelium is essential to avoid being excreted together with the digested blood meal. Promastigote and gut sand fly surface glycans are important ligands in this attachment. The purpose of the present study was to evaluate the interaction of three lectins isolated from leguminous seeds (Diocleinae subtribe, D-glucose and D-mannose-binding, with glycans on Lutzomyia migonei midgut. To study this interaction the lectins were labeled with FITC and a fluorescence assay was performed. The results showed that only Dioclea violacea lectin (DVL was able to interact with midgut glycans, unlike Cratylia floribunda lectin (CFL and Canavalia gladiata lectin (CGL. Furthermore, when DVL was blocked with D-mannose the interaction was inhibited. Differences of spatial arrangement of residues and volume of carbohydrate recognition domain (CRD may be the cause of the fine specificity of DVL for glycans in the surface on Lu. migonei midgut. The findings in this study showed the presence of glycans in the midgut with glucose/mannose residues in its composition and these residues may be important in interaction between Lu. migonei midgut and Leishmania.

  20. Spores of Mucor ramosissimus, Mucor plumbeus and Mucor circinelloides and their ability to activate human complement system in vitro.

    Science.gov (United States)

    Granja, Luiz Fernando Zmetek; Pinto, Lysianne; Almeida, Cátia Amancio; Alviano, Daniela Sales; Da Silva, Maria Helena; Ejzemberg, Regina; Alviano, Celuta Sales

    2010-03-01

    Complement activation by spores of Mucor ramosissimus, Mucor plumbeus and Mucor circinelloides was studied using absorbed human serum in the presence or absence of chelators (EGTA or EDTA). We found that the spore caused full complement activation when incubated with EGTA-Mg2+ or without chelators, indicating that the alternative pathway is mainly responsible for this response. In order to compare activation profiles from each species, ELISAs for C3 and C4 fragments, mannan binding lectin (MBL), C-reactive protein (CRP) and IgG studies were carried out. All proteins were present on the species tested. Immunofluorescence tests demonstrated the presence of C3 fragments on the surface of all samples, which were confluent throughout fungal surfaces. The same profile of C3, C4, MBL, CRP and IgG deposition, observed in all species, suggests a similar activation behavior for these species.

  1. "Click" saccharide/beta-lactam hybrids for lectin inhibition.

    Science.gov (United States)

    Palomo, Claudio; Aizpurua, Jesus M; Balentová, Eva; Azcune, Itxaso; Santos, J Ignacio; Jiménez-Barbero, Jesús; Cañada, Javier; Miranda, José Ignacio

    2008-06-05

    Hybrid glycopeptide beta-lactam mimetics designed to bind lectins or carbohydrate recognition domains in selectins have been prepared according to a "shape-modulating linker" design. This approach was implemented using the azide-alkyne "click" cycloaddition reaction, and as shown by NMR/MD experiments, binding of the resulting mimetics to Ulex Europaeus Lectin-1 (UEL-1) occurred after a "bent-to-extended" conformational change around a partially rotatable triazolylmethylene moiety.

  2. Identification and characterization of a novel legume-like lectin ...

    Indian Academy of Sciences (India)

    A legume-type lectin (L-lectin) gene of the red algae Gracilaria fisheri (GFL) was cloned by rapid amplification of cDNA ends (RACE). The full-length cDNA of GFL was 1714 bp and contained a 1542 bp open reading frame encoding 513 amino acids with a predicted molecular mass of 56.5 kDa. Analysis of the putative ...

  3. C3 rho-inhibitor for targeted pharmacological manipulation of osteoclast-like cells.

    Directory of Open Access Journals (Sweden)

    Andrea Tautzenberger

    Full Text Available The C3 toxins from Clostridium botulinum (C3bot and Clostridium limosum (C3lim as well as C3-derived fusion proteins are selectively taken up into the cytosol of monocytes/macrophages where the C3-catalyzed ADP-ribosylation of Rho results in inhibition of Rho-signalling and characteristic morphological changes. Since the fusion toxin C2IN-C3lim was efficiently taken up into and inhibited proliferation of murine macrophage-like RAW 264.7 cells, its effects on RAW 264.7-derived osteoclasts were investigated. C2IN-C3lim was taken up into differentiated osteoclasts and decreased their resorption activity. In undifferentiated RAW 264.7 cells, C2IN-C3lim-treatment significantly decreased their differentiation into osteoclasts as determined by counting the multi-nucleated, TRAP-positive cells. This inhibitory effect was concentration- and time-dependent and most efficient when C2IN-C3lim was applied in the early stage of osteoclast-formation. A single-dose application of C2IN-C3lim at day 0 and its subsequent removal at day 1 reduced the number of osteoclasts in a comparable manner while C2IN-C3lim-application at later time points did not reduce the number of osteoclasts to a comparable degree. Control experiments with an enzymatically inactive C3 protein revealed that the ADP-ribosylation of Rho was essential for the observed effects. In conclusion, the results indicate that Rho-activity is crucial during the early phase of osteoclast-differentiation. Other bone cell types such as pre-osteoblastic cells were not affected by C2IN-C3lim. Due to their cell-type selective and specific mode of action, C3 proteins and C3-fusions might be valuable tools for targeted pharmacological manipulation of osteoclast formation and activity, which could lead to development of novel therapeutic strategies against osteoclast-associated diseases.

  4. A Lactose-Binding Lectin from the Marine Sponge Cinachyrella Apion (Cal) Induces Cell Death in Human Cervical Adenocarcinoma Cells

    Science.gov (United States)

    Rabelo, Luciana; Monteiro, Norberto; Serquiz, Raphael; Santos, Paula; Oliveira, Ruth; Oliveira, Adeliana; Rocha, Hugo; Morais, Ana Heloneida; Uchoa, Adriana; Santos, Elizeu

    2012-01-01

    Cancer represents a set of more than 100 diseases, including malignant tumors from different locations. Strategies inducing differentiation have had limited success in the treatment of established cancers. Marine sponges are a biological reservoir of bioactive molecules, especially lectins. Several animal and plant lectins were purified with antitumor activity, mitogenic, anti-inflammatory and antiviral, but there are few reports in the literature describing the mechanism of action of lectins purified from marine sponges to induce apoptosis in human tumor cells. In this work, a lectin purified from the marine sponge Cinachyrella apion (CaL) was evaluated with respect to its hemolytic, cytotoxic and antiproliferative properties, besides the ability to induce cell death in tumor cells. The antiproliferative activity of CaL was tested against HeLa, PC3 and 3T3 cell lines, with highest growth inhibition for HeLa, reducing cell growth at a dose dependent manner (0.5–10 µg/mL). Hemolytic activity and toxicity against peripheral blood cells were tested using the concentration of IC50 (10 µg/mL) for both trials and twice the IC50 for analysis in flow cytometry, indicating that CaL is not toxic to these cells. To assess the mechanism of cell death caused by CaL in HeLa cells, we performed flow cytometry and western blotting. Results showed that lectin probably induces cell death by apoptosis activation by pro-apoptotic protein Bax, promoting mitochondrial membrane permeabilization, cell cycle arrest in S phase and acting as both dependent and/or independent of caspases pathway. These results indicate the potential of CaL in studies of medicine for treating cancer. PMID:22690140

  5. A Lactose-Binding Lectin from the Marine Sponge Cinachyrella Apion (Cal Induces Cell Death in Human Cervical Adenocarcinoma Cells

    Directory of Open Access Journals (Sweden)

    Adriana Uchoa

    2012-03-01

    Full Text Available Cancer represents a set of more than 100 diseases, including malignant tumors from different locations. Strategies inducing differentiation have had limited success in the treatment of established cancers. Marine sponges are a biological reservoir of bioactive molecules, especially lectins. Several animal and plant lectins were purified with antitumor activity, mitogenic, anti-inflammatory and antiviral, but there are few reports in the literature describing the mechanism of action of lectins purified from marine sponges to induce apoptosis in human tumor cells. In this work, a lectin purified from the marine sponge Cinachyrella apion (CaL was evaluated with respect to its hemolytic, cytotoxic and antiproliferative properties, besides the ability to induce cell death in tumor cells. The antiproliferative activity of CaL was tested against HeLa, PC3 and 3T3 cell lines, with highest growth inhibition for HeLa, reducing cell growth at a dose dependent manner (0.5–10 µg/mL. Hemolytic activity and toxicity against peripheral blood cells were tested using the concentration of IC50 (10 µg/mL for both trials and twice the IC50 for analysis in flow cytometry, indicating that CaL is not toxic to these cells. To assess the mechanism of cell death caused by CaL in HeLa cells, we performed flow cytometry and western blotting. Results showed that lectin probably induces cell death by apoptosis activation by pro-apoptotic protein Bax, promoting mitochondrial membrane permeabilization, cell cycle arrest in S phase and acting as both dependent and/or independent of caspases pathway. These results indicate the potential of CaL in studies of medicine for treating cancer.

  6. Evaluation of glycophenotype in breast cancer by quantum dot-lectin histochemistry

    Directory of Open Access Journals (Sweden)

    Andrade CG

    2013-12-01

    Full Text Available Camila G Andrade,1 Paulo E Cabral Filho,2 Denise PL Tenório,3 Beate S Santos,4 Eduardo IC Beltrão,1 Adriana Fontes,2 Luiz B Carvalho Jr1 1Keizo Asami Immunopathology Laboratory, 2Biophysics and Radiobiology Department, 3Fundamental Chemistry Department, 4Pharmaceutical Science Department, Federal University of Pernambuco, Recife, Pernambuco, Brazil Abstract: Cell surface glycoconjugates play an important role in differentiation/dedifferentiation processes and lectins are employed to evaluate them by several methodologies. Fluorescent probes are considered a valuable tool because of their ability to provide a particular view, and are more detailed and sensitive in terms of cell structure and molecular content. The aim of this study was to evaluate and compare the expression and distribution of glycoconjugates in normal human breast tissue, and benign (fibroadenoma, and malignantly transformed (invasive ductal carcinoma breast tissues. For this, we used mercaptosuccinic acid-coated Cadmium Telluride (CdTe quantum dots (QDs conjugated with concanavalin A (Con A or Ulex europaeus agglutinin I (UEA I lectins to detect α-D-glucose/mannose and L-fucose residues, respectively. The QD-lectin conjugates were evaluated by hemagglutination activity tests and carbohydrate inhibition assays, and were found to remain functional, keeping their fluorescent properties and carbohydrate recognition ability. Fluorescence images showed that different regions of breast tissue expressed particular types of carbohydrates. While the stroma was preferentially and intensely stained by QD-Con A, ductal cells were preferentially labeled by QD-UEA I. These results indicate that QD-lectin conjugates can be used as molecular probes and can help to elucidate the glycoconjugate profile in biological processes. Keywords: nanoparticles, concanavalin A, Ulex europaeus, carbohydrates, mammary tissues

  7. Glycoconjugate sugar residues in the chick embryo developing lung: a lectin histochemical study.

    Science.gov (United States)

    Gheri, G; Sgambati, E; Bryk, S G

    2000-03-01

    A lectin histochemical study was performed to investigate the distribution and changes of the oligosaccharidic component of the glycoconjugates in the lung of chick embryos, of 1-day-old chick, and of the adult animal. For this purpose, a battery of seven horseradish peroxidase-conjugated lectins (PNA, SBA, DBA, WGA, Con A, LTA, and UEA I) were employed. During the first phase of parabronchi and atria formation, D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine, alpha-D-mannose, and sialic acid, present at the level of the surface and of cytoplasmic granules of the lining epithelial cells, seem to play a role in regulating morphogenetic phenomena. In the subsequent phases, the parabronchial lumen and the atrial cavities were characterized by the presence of lectin-reactive material rich in terminal D-galactose-(beta1-->3)-N-acetyl-D-galactosamine, beta-N-acetyl-D-galactosamine, D-glucosamine and alpha-D-mannose. From day 18 onwards and immediately after hatching, the free border of the cells lining the air capillaries was characterized by the presence of beta-N-acetyl-D-galactosamine and alpha-D-mannose. The appearance of these sugar residues was concomitant with the beginning of respiratory activity. Copyright 2000 Wiley-Liss, Inc.

  8. A sheep hydatid cyst glycoprotein as receptors for three toxic lectins, as well as Abrus precatorius and Ricinus communis agglutinins.

    Science.gov (United States)

    Wu, A M; Song, S C; Wu, J H; Pfüller, U; Chow, L P; Lin, J Y

    1995-01-18

    The binding properties of a glycoprotein with blood group P1 specificity isolated from sheep hydatid cyst fluid with Gal and GalNAc specific lectins was investigated by quantitative precipitin and precipitin inhibition assays. The glycoprotein completely precipitated Ricinus communis agglutinin (RCA1), Abrus precatorius agglutinin (APA) and Mistletoe toxic lectin-I (ML-I). Only 1.0 microgram of P1 glycoprotein was required to precipitate 50% of 5.1 micrograms ML-I nitrogen. It also reacted well with abrin-a and ricin, precipitating over 73% of the lectin nitrogen added, but poorly or weakly with Dolichos biflorus (DBL), Vicia villosa (VVL, a mixture of A4, A2B2 and B4), VVL-B4, Arachis hypogaea (PNA), Maclura pomifera (MPL), Bauchinia purpurea alba (BPL) and Wistaria floribunda (WFL) lectins. When an inhibition assay in the range of 5.1 micrograms N to 5.9 micrograms N of lectins (ML-I, abrin-a; ricin, RCA1, and APA, and 10 micrograms P1 active glycoprotein interaction was performed; from 76 to 100% of the precipitations were inhibited by 0.44 and 0.52 mumol of Gal alpha 1-->4Gal and Gal beta 1-->4GlcNAc, respectively, but not or insignificantly with 1.72 mumol of GlcNAc. The Gal alpha 1-->4Gal disaccharide found in this P1 active glycoprotein is a frequently occurring sequence of many glycosphingolipids located at the surface of mammalian cell membranes, especially human erythrocytes and intestinal cells for ligand binding and microbial toxin attachment. The present finding suggests that the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in this P1 active glycoprotein is one of the best glycoprotein receptors for three toxic lectins (ricin, abrin-a, and ML-I) as well as for APA, and RCA1, and the result of inhibition assay implies that these lectins are recognizing part or all of the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in the P1 active glycoprotein.

  9. Neuroprotective Efficacy of an Aminopropyl Carbazole Derivative P7C3-A20 in Ischemic Stroke.

    Science.gov (United States)

    Wang, Shu-Na; Xu, Tian-Ying; Wang, Xia; Guan, Yun-Feng; Zhang, Sai-Long; Wang, Pei; Miao, Chao-Yu

    2016-09-01

    NAMPT is a novel therapeutic target of ischemic stroke. The aim of this study was to investigate the effect of a potential NAMPT activator, P7C3-A20, an aminopropyl carbazole derivative, on ischemic stroke. In vitro study, neuron protection effect of P7C3-A20 was investigated by co-incubation with primary neurons subjected to oxygen-glucose deprivation (OGD) or oxygen-glucose deprivation/reperfusion (OGD/R) injury. In vivo experiment, P7C3-A20 was administrated in middle cerebral artery occlusion (MCAO) rats and infarct volume was examined. Lastly, the brain tissue nicotinamide adenine dinucleotide (NAD) levels were detected in P7C3-A20 treated normal or MCAO mice. Cell viability, morphology, and Tuj-1 staining confirmed the neuroprotective effect of P7C3-A20 in OGD or OGD/R model. P7C3-A20 administration significantly reduced cerebral infarction in MCAO rats. Moreover, brain NAD levels were elevated both in normal and MCAO mice after P7C3-A20 treatment. P7C3-A20 has neuroprotective effect in cerebral ischemia. The study contributes to the development of NAMPT activators against ischemic stroke and expands the horizon of the neuroprotective effect of aminopropyl carbazole chemicals. © 2016 John Wiley & Sons Ltd.

  10. Hyperglycemic conditions inhibit C3-mediated immunologic control of Staphylococcus aureus

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    Hair Pamela S

    2012-03-01

    Full Text Available Abstract Background Diabetic patients are at increased risk for bacterial infections; these studies provide new insight into the role of the host defense complement system in controlling bacterial pathogens in hyperglycemic environments. Methods The interactions of complement C3 with bacteria in elevated glucose were assayed for complement activation to opsonic forms, phagocytosis and bacterial killing. C3 was analyzed in euglycemic and hyperglycemic conditions by mass spectrometry to measure glycation and structural differences. Results Elevated glucose inhibited S. aureus activation of C3 and deposition of C3b and iC3b on the bacterial surface. S. aureus-generated C5a and serum-mediated phagocytosis by neutrophils were both decreased in elevated glucose conditions. Interestingly, elevated glucose increased the binding of unactivated C3 to S. aureus, which was reversible on return to normal glucose concentrations. In a model of polymicrobial infection, S. aureus in elevated glucose conditions depleted C3 from serum resulting in decreased complement-mediated killing of E. coli. To investigate the effect of differing glucose concentration on C3 structure and glycation, purified C3 incubated with varying glucose concentrations was analyzed by mass spectrometry. Glycation was limited to the same three lysine residues in both euglycemic and hyperglycemic conditions over one hour, thus glycation could not account for observed changes between glucose conditions. However, surface labeling of C3 with sulfo-NHS-biotin showed significant changes in the surface availability of seven lysine residues in response to increasing glucose concentrations. These results suggest that the tertiary structure of C3 changes in response to hyperglycemic conditions leading to an altered interaction of C3 with bacterial pathogens. Conclusions These results demonstrate that hyperglycemic conditions inhibit C3-mediated complement effectors important in the immunological

  11. Enhanced photocatalytic ozonation of organics by g-C3N4 under visible light irradiation

    International Nuclear Information System (INIS)

    Liao, Gaozu; Zhu, Dongyun; Li, Laisheng; Lan, Bingyan

    2014-01-01

    Highlights: • g-C 3 N 4 is employed as active catalyst in the photocatalytic ozonation system. • The more negative conduction band of g-C 3 N 4 benefits the transfer of electrons. • The synergistic effect between photocatalysis and ozonation is promoted by g-C 3 N 4 . • Enhanced degradation of oxalic acid and biphenol A is achieved via g-C 3 N 4 /Vis/O 3 . - Abstract: Graphitic carbon nitride (g-C 3 N 4 ) was employed as the active photocatalyst in the photocatalytic ozonation coupling system in the present study. g-C 3 N 4 was prepared by directly heating thiourea in air at 550 °C. XRD, FT-IR, UV–vis was used to characterize the structure and optical property. Oxalic acid and bisphenol A were selected as model substances for photocatalytic ozonation reactions to evaluate the catalytic ability of g-C 3 N 4 (g-C 3 N 4 /Vis/O 3 ). The results showed that the degradation ratio of oxalic acid with g-C 3 N 4 /Vis/O 3 was 65.2% higher than the sum of ratio when it was individually decomposed by g-C 3 N 4 /Vis and O 3 . The TOC removal of biphenol A with g-C 3 N 4 /Vis/O 3 was 2.17 times as great as the sum of the ratio when using g-C 3 N 4 /Vis and O 3 . This improvement was attributed to the enhanced synergistic effect between photocatalysis and ozonation by g-C 3 N 4 . Under visible light irradiation, the photo-generated electrons produced on g-C 3 N 4 facilitated the electrons transfer owing to the more negative conduction band potential (−1.3 V versus NHE). It meant that the photo-generated electrons could be trapped by ozone and reaction with it more easily. Subsequently, the yield of hydroxyl radicals was improved so as to enhance the organics degradation efficiency. This work indicated that metal-free g-C 3 N 4 could be an excellent catalyst for mineralization of organic compounds in waste control

  12. Direct analysis of the lectin reactivity of alpha-fetoprotein in maternal serum by crossed affinity radio-immunoelectrophoresis

    International Nuclear Information System (INIS)

    Kerckaert, J.P.; Bayard, B.; Biserte, G.; Puech, F.; Codaccioni, X.

    1980-01-01

    Affinity experiments with the lentil (Lens culinaris) lectin have revealed the existence of two distinct molecular populations of alpha-fetoprotein: lectin reactive and lectin non-reactive. Using a combination of crossed lectin immunoelectrophoresis and radio-immunoelectrophoresis, it has been possible to obtain directly the lentil lectin affinity patterns of alpha-fetoprotein present in maternal sera. The lentil lectin reactivity of maternal alpha-fetoprotein decreases almost linearly with the gestational age from week 15 to 35. (Auth.)

  13. Association between lectin complement pathway initiators, C-reactive protein and left ventricular remodeling in myocardial infarction-a magnetic resonance study

    DEFF Research Database (Denmark)

    Schoos, Mikkel Malby; Munthe-Fog, Lea; Skjoedt, Mikkel-Ole

    2013-01-01

    Lectin complement pathway (LP) activation is an important mechanism in myocardial ischemia reperfusion injury (IRI). LP is activated via the recognition molecules mannose-binding lectin (MBL), ficolins-2 and-3 and is regulated by MBL/Ficolin-associated Protein-1 (MAP-1). Also, C-reactive protein...... (CRP) and ficolin-2 interact in vitro, but the role of the ficolins in IRI is unknown.Methods and results In 55 patients with ST segment elevation myocardial infarction, we investigated the association of LP components and CRP in plasma samples with left ventricular (LV) end systolic and diastolic......-activation in IRI and LV remodeling....

  14. Circulating C3 levels predict renal and global outcome in patients with renal vasculitis.

    Science.gov (United States)

    Villacorta, Javier; Diaz-Crespo, Francisco; Acevedo, Mercedes; Cavero, Teresa; Guerrero, Carmen; Praga, Manuel; Fernandez-Juarez, Gema

    2016-11-01

    Several studies have demonstrated the crucial role of complement activation in the pathogenesis of ANCA-associated vasculitis. We aimed to assess the association between baseline serum C3 (sC3) levels and long-term outcomes in patients with renal vasculitis. This retrospective study included 111 patients with renal vasculitis from three hospitals who underwent a renal biopsy between 1997 and 2014. Serum levels of C3 were measured at the onset and the study population was divided into three tertiles according to sC3 concentrations (tertile 1 128 mg/dl). Patients with lower sC3 (tertile 1) were compared with those having higher levels of sC3 (tertile 2 and tertile 3). Histological, clinical, and laboratory data were recorded for analysis. The primary end point was the composite of end-stage renal disease (ESRD) and death from any cause. Lower sC3 levels were associated with a higher need for dialysis and lower response rate to treatment (p = 0.04 and p = 0.007, respectively). Renal and global survival at 1 and 5 years was 53 and 46 % in patients with lower sC3 (tertile 1) compared with 72 and 65 % in patients with higher sC3 (upper two tertiles) (p = 0.04). In a multivariate Cox-regression model, when adjusted by renal function and histopatholologic categories, lower sC3 remained as an independent predictor of ESRD and death (HR, 1.9; 95 % CI, 1.1 to 3.4; p = 0.02). Baseline serum C3 levels have an independent prognostic value in predicting long-term renal and global survival in patients with renal vasculitis.

  15. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Directory of Open Access Journals (Sweden)

    Eduardo Balsanelli

    Full Text Available Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs were isolated and mass spectrometry (MS analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  16. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Science.gov (United States)

    Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; Pedrosa, Fabio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2013-01-01

    Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  17. Synthesis of C3/C1-Substituted Tetrahydroisoquinolines

    Directory of Open Access Journals (Sweden)

    Mohamed Mihoubi

    2015-08-01

    Full Text Available A broad biological screening of the natural alkaloid N-methylisosalsoline (2 extracted from Hammada scoparia leaves against a panel of human and parasitic proteases revealed an interesting activity profile of 2 towards human 20S proteasome. This outcome suggests that the 1,2,3,4-tetrahydroisoquinoline skeleton may be exploited as a template for the development of novel anticancer agents. In this article, we report the synthesis and chemical characterization of a new series of isosalsoline-type alkaloids (10–11 with variations at N2 and C3 positions with respect to the natural Compound 2, obtained by a synthetic strategy that involves the Bischler-Napieralski cyclization. The substrate for the condensation to the tetrahydroisoquinoline system, i.e., a functionalized β-arylethyl amine, was obtained through an original double reduction of nitroalkene. The synthetic strategy can be directed to the construction of highly substituted and functionalized 1,2,3,4-tetrahydroisoquinolines.

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

    Science.gov (United States)

    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.

  19. A potent complement factor C3 specific nanobody inhibiting multiple functions in the alternative pathway of human and murine complement.

    Science.gov (United States)

    Jensen, Rasmus K; Pihl, Rasmus; Gadeberg, Trine A F; Jensen, Jan K; Andersen, Kasper R; Thiel, Steffen; Laursen, Nick S; Andersen, Gregers Rom

    2018-03-01

    The complement system is a complex, carefully regulated proteolytic cascade for which suppression of aberrant activation is of increasing clinical relevance and inhibition of the complement alternative pathway is a subject of intense research. Here, we describe the nanobody hC3Nb1 that binds to multiple functional states of C3 with sub-nanomolar affinity. The nanobody causes a complete shutdown of alternative pathway activity in human and murine serum when present in concentrations comparable to C3, and hC3Nb1 is shown to prevent both proconvertase assembly as well as binding of the C3 substrate to C3 convertases. Our crystal structure of the C3b-hC3Nb1 complex and functional experiments demonstrate that proconvertase formation is blocked by steric hindrance between the nanobody and an Asn-linked glycan on complement factor B. In addition, hC3Nb1 is shown to prevent factor H binding to C3b rationalizing its inhibition of factor I activity. Our results identify hC3Nb1 as a versatile, inexpensive, and powerful inhibitor of the alternative pathway in both human and murine in vitro model systems of complement activation. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Ulex europaeus agglutinin II (UEA-II) is a novel, potent inhibitor of complement activation.

    Science.gov (United States)

    Lekowski, R; Collard, C D; Reenstra, W R; Stahl, G L

    2001-02-01

    Complement is an important mediator of vascular injury following oxidative stress. We recently demonstrated that complement activation following endothelial oxidative stress is mediated by mannose-binding lectin (MBL) and activation of the lectin complement pathway. Here, we investigated whether nine plant lectins which have a binding profile similar to that of MBL competitively inhibit MBL deposition and subsequent complement activation following human umbilical vein endothelial cell (HUVEC) oxidative stress. HUVEC oxidative stress (1% O(2), 24 hr) significantly increased Ulex europaeus agglutinin II (UEA-II) binding by 72 +/- 9% compared to normoxic cells. UEA-II inhibited MBL binding to HUVEC in a concentration-dependent manner following oxidative stress. Further, MBL inhibited UEA-II binding to HUVEC in a concentration-dependent manner following oxidative stress, suggesting a common ligand. UEA-II (< or = 100 micromol/L) did not attenuate the hemolytic activity, nor did it inhibit C3a des Arg formation from alternative or classical complement pathway-specific hemolytic assays. C3 deposition (measured by ELISA) following HUVEC oxidative stress was inhibited by UEA-II in a concentration-dependent manner (IC(50) = 10 pmol/L). UEA-II inhibited C3 and MBL co-localization (confocal microscopy) in a concentration-dependent manner on HUVEC following oxidative stress (IC(50) approximately 1 pmol/L). Finally, UEA-II significantly inhibited complement-dependent neutrophil chemotaxis, but failed to inhibit fMLP-mediated chemotaxis, following endothelial oxidative stress. These data demonstrate that UEA-II is a novel, potent inhibitor of human MBL deposition and complement activation following human endothelial oxidative stress.

  1. Mistletoe lectin I in complex with galactose and lactose reveals distinct sugar-binding properties

    International Nuclear Information System (INIS)

    Mikeska, Ruth; Wacker, Roland; Arni, Raghuvir; Singh, Tej P.; Mikhailov, Albert; Gabdoulkhakov, Azat; Voelter, Wolfgang; Betzel, Christian

    2004-01-01

    The structures of mistletoe lectin I in complex with lactose and galactose reveal differences in binding by the two known sites in subdomains α1 and γ2 and suggest the presence of a third low-affinity site in subdomain β1. The structures of mistletoe lectin I (ML-I) from Viscum album complexed with lactose and galactose have been determined at 2.3 Å resolution and refined to R factors of 20.9% (R free = 23.6%) and 20.9 (R free = 24.6%), respectively. ML-I is a heterodimer and belongs to the class of ribosome-inactivating proteins of type II, which consist of two chains. The A-chain has rRNA N-glycosidase activity and irreversibly inhibits eukaryotic ribosomes. The B-chain is a lectin and preferentially binds to galactose-terminated glycolipids and glycoproteins on cell membranes. Saccharide binding is performed by two binding sites in subdomains α1 and γ2 of the ML-I B-chain separated by ∼62 Å from each other. The favoured binding of galactose in subdomain α1 is achieved via hydrogen bonds connecting the 4-hydroxyl and 3-hydroxyl groups of the sugar moiety with the side chains of Asp23B, Gln36B and Lys41B and the main chain of 26B. The aromatic ring of Trp38B on top of the preferred binding pocket supports van der Waals packing of the apolar face of galactose and stabilizes the sugar–lectin complex. In the galactose-binding site II of subdomain γ2, Tyr249B provides the hydrophobic stacking and the side chains of Asp235B, Gln238B and Asn256B are hydrogen-bonding partners for galactose. In the case of the galactose-binding site I, the 2-hydroxyl group also stabilizes the sugar–protein complex, an interaction thus far rarely detected in galactose-specific lectins. Finally, a potential third low-affinity galactose-binding site in subunit β1 was identified in the present ML-I structures, in which a glycerol molecule from the cryoprotectant buffer has bound, mimicking the sugar compound

  2. Tear fluid analysis in patients with primary Sjögren's syndrome using lectin probes

    DEFF Research Database (Denmark)

    Bjerrum, Kirsten Birgitte

    1999-01-01

    Ophthalmology, Sjögren's syndrome, dry eye, keratoconjunctivitis sicca, glycoprotein, mucus, lectins, Coomassie, electrophoresis, SDS-PAGE-blotting......Ophthalmology, Sjögren's syndrome, dry eye, keratoconjunctivitis sicca, glycoprotein, mucus, lectins, Coomassie, electrophoresis, SDS-PAGE-blotting...

  3. Mannan-Binding Lectin in Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Izabela Pągowska-Klimek

    2014-01-01

    Full Text Available 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.

  4. Synthesis and characterization of "1"3C_3-tristearin

    International Nuclear Information System (INIS)

    Wu Hangyu; Lin Lin; Li Lei; Chen Dazhou

    2011-01-01

    A highly efficient synthesis of "1"3C_3 labeled triglycerides of stearic acids from "1"3C_3-glycerol and stearic acids, by immobilized lipase-catalyzed in solvent-free medium was described. The structure of the product were characterized by fourier transform infrared spectrum (FT-IR), nuclear magnetic resonance (NMR), mass spectra (MS). The results showed that triglycerides of stearic acids contained three "1"3C atoms. The isotope abundance of "1"3C_3-tristearin was more than 99% and the yield was 80% of "1"3C_3-tristearin through calculation. Chemical purity (> 98%) was obtained by differential scanning calorimetry (DSC). (authors)

  5. C-type Lectin Receptors for Tumor Eradication: Future Directions

    Energy Technology Data Exchange (ETDEWEB)

    Streng-Ouwehand, Ingeborg; Unger, Wendy W. J.; Kooyk, Yvette van, E-mail: y.vankooyk@vumc.nl [Department of Molecular Cell Biology and Immunology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2011-08-08

    Dendritic cells are key regulators in directing immune responses and therefore are under extensive research for the induction of anti-tumor responses. DCs express a large array of receptors by which they scan their surroundings for recognition and uptake of pathogens. One of the receptor-families is the C-type lectins (CLR), which bind carbohydrate structures and internalize antigens upon recognition. Intracellular routing of antigen through CLR enhances loading and presentation of antigen through MHC class I and II, inducing antigen-specific CD4{sup +} and CD8{sup +} T-cell proliferation and skewing T-helper cells. These characteristics make CLRs very interesting targets for DC-based immunotherapy. Profound research has been done on targeting specific tumor antigens to CLR using either antibodies or the natural ligands such as glycan structures. In this review we will focus on the current data showing the potency of CLR-targeting and discuss improvements that can be achieved to enhance anti-tumor activity in the near future.

  6. Lectin I from Bauhinia variegata (BVL-I) expressed by Pichia pastoris inhibits initial adhesion of oral bacteria in vitro.

    Science.gov (United States)

    Klafke, Gabriel Baracy; Moreira, Gustavo Marçal Schmidt Garcia; Pereira, Juliano Lacava; Oliveira, Patrícia Diaz; Conceição, Fabricio Rochedo; Lund, Rafael Guerra; Grassmann, André Alex; Dellagostin, Odir Antonio; da Silva Pinto, Luciano

    2016-12-01

    Lectins are non-immune proteins that reversibly bind to carbohydrates in a specific manner. Bauhinia variegata lectin I (BVL-I) is a Gal/GalNAc-specific, single-chain lectin isolated from Bauhinia variegata seeds that has been implicated in the inhibition of bacterial adhesion and the healing of damaged skin. Since the source of the native protein (nBVL) is limited, this study aimed to produce recombinant BVL-I in Pichia pastoris (rBVL-Ip). The coding sequence for BVL-I containing preferential codons for P. pastoris was cloned into the pPICZαB plasmid. A single expressing clone was selected and fermented, resulting in the secretion and glycosylation of the protein. Fed-batch fermentation in 7L-scale was performed, and the recombinant lectin was purified from culture supernatant, resulting in a yield of 1.5mg/L culture. Further, rBVL-Ip was compared to nBVL and its recombinant version expressed in Escherichia coli BL21 (DE3) (rBVL-Ie). Although it was expressed as a monomer, rBVL-Ip retained its biological activity since it was able to impair the initial adhesion of Streptococcus mutans and S. sanguinis in an in vitro model of biofilm formation and bacterial adhesion. In summary, rBVL-Ip produced in Pichia pastoris represents a viable alternative to large-scale production, encouraging further biological application studies with this lectin. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Lectin histochemical evaluation of glycoconjugates in dog efferent ductules.

    Science.gov (United States)

    Wakui, S; Furusato, M; Takahashi, H; Motoya, M; Ushigome, S

    1996-06-01

    Glycoconjugates in the epithelial cells of the efferent ductules in the dog were investigated using lectin histochemistry. These ductules connect the extratesticular rete with the epididymis. The epithelium of the ductules consisted both of ciliated and nonciliated cells. Whereas the apical zone of ciliated cells showed selective binding with WGA, SWGA, SNA, MAA and neuraminidase-PNA, that of nonciliated cells bound to all lectins used in the present study: WGA, SWGA, SNA, MAA, PNA, neuraminidase-PNA, RCA1, DBA and SBA. The nonciliated cells were divided into 3 types: type A cells which lacked both specific granules and vacuoles, type B cells which were characterised by a few specific apical vacuoles and many large specific granules, and type C cells which were characterised by some specific apical vacuoles and small basal granules. The specific granules and vacuoles of type B cells showed binding with WGA, SWGA and MAA. The specific granules of type C cells showed binding with WGA, SWGA, SNA, MAA, PNA and neuraminidase-PNA, while their specific vacuoles showed binding with WGA, SWGA, SNA and MAA. The Golgi zone both of ciliated and type A cells did not bind with any lectins used in this study, while type B and C cells showed similar lectin binding patterns between the Golgi zone and their specific granules. Specific lectin binding patterns revealed a different carbohydrate composition of each type of cell, indicating a biological difference between the ciliated cells and the 3 types of nonciliated cells in dog efferent ductules.

  8. Chemical fractionations in meteorites. IX. C3 chondrites

    Energy Technology Data Exchange (ETDEWEB)

    Anders, E; Higuchi, H; Ganapathy, R; Morgan, J W [Chicago Univ., Ill. (USA). Enrico Fermi Inst.

    1976-09-01

    Four C3V chondrites (Grosnaja, Kaba, Mokoia, Vigarano) and three C30 chondrites (Felic, Kainsaz, and Lance) were analyzed by radiochemical neutron activation for 17 trace elements. Both classes show a typical chondritic step pattern, reflecting loss of volatiles during chondrule formation. Elements condensing above 1300 K (U, Re, Ir, Ni) are present in essentially C1 chondrite proportions, while moderately volatile elements condensing between 1300 K and 800 K (Ge, Rb, Ag) are depleted by a factor of 0.44. However, elements condensing below 700 K (S, Cs, Bi, Tl, Br, Se, Te, In, Cd) are depleted to a still greater degree, and more so in the Ornans subclass (factor of 0.24, except Cd 0.007) than in the Vigarano subclass (factor of 0.29). This additional depletion may be due to a slight (less than 3-fold) dust-gas fractionation, by settling of dust to the median plane of the solar nebula. Among other chondrite classes, ordinary chondrites show a similar depletion, but C2 chondrites do not. Possibly the undepleted meteorites formed in one of the convection zones of the nebula predicted by Cameron and Pine, whereas the depleted meteorites formed in a quiescent region. The condensation of chalocophile elements as a function of H/sub 2/S partial pressure is discussed, in an attempt to explain the drastic difference in Cd abundance between the two subclasses. It appears that the H/sub 2/S/H/sub 2/ ratio is the key variable. C30's seem to have condensed in a region where enough metallic Fe was present to buffer the H/sub 2/S pressure, while C3V's condensed in a more oxidized region, where H/sub 2/S was in excess. Accretion temperatures, for an assumed nebular pressure of 10/sup -5/ atm, were between 415 and 430 K for C30's and less than 440 K for CeV's.

  9. Lectins binding during alloxan-induced diabetes in rat soleus muscle

    African Journals Online (AJOL)

    Membrane structural changes of soleus muscle of alloxan-diabetic rats were detected with a panel of six biotinylated lectins. Samples of muscles were obtained from normal and diabetic rats. The biotinylated lectins in staining were detected by avidin-peroxidase complex. Lectin stainning of soleus muscle cryostat sections ...

  10. DMPD: C-type lectin receptors in antifungal immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18160296 C-type lectin receptors in antifungal immunity. Willment JA, Brown GD. Tre...nds Microbiol. 2008 Jan;16(1):27-32. Epub 2007 Dec 21. (.png) (.svg) (.html) (.csml) Show C-type lectin receptors in antifun...gal immunity. PubmedID 18160296 Title C-type lectin receptors in antifungal immunity. Author

  11. A recombinant fusion toxin based on enzymatic inactive C3bot1 selectively targets macrophages.

    Directory of Open Access Journals (Sweden)

    Lydia Dmochewitz

    Full Text Available BACKGROUND: The C3bot1 protein (~23 kDa from Clostridium botulinum ADP-ribosylates and thereby inactivates Rho. C3bot1 is selectively taken up into the cytosol of monocytes/macrophages but not of other cell types such as epithelial cells or fibroblasts. Most likely, the internalization occurs by a specific endocytotic pathway via acidified endosomes. METHODOLOGY/PRINCIPAL FINDINGS: Here, we tested whether enzymatic inactive C3bot1E174Q serves as a macrophage-selective transport system for delivery of enzymatic active proteins into the cytosol of such cells. Having confirmed that C3bot1E174Q does not induce macrophage activation, we used the actin ADP-ribosylating C2I (∼50 kDa from Clostridium botulinum as a reporter enzyme for C3bot1E174Q-mediated delivery into macrophages. The recombinant C3bot1E174Q-C2I fusion toxin was cloned and expressed as GST-protein in Escherichia coli. Purified C3bot1E174Q-C2I was recognized by antibodies against C2I and C3bot and showed C2I-specific enzyme activity in vitro. When applied to cultured cells C3bot1E174Q-C2I ADP-ribosylated actin in the cytosol of macrophages including J774A.1 and RAW264.7 cell lines as well as primary cultured human macrophages but not of epithelial cells. Together with confocal fluorescence microscopy experiments, the biochemical data indicate the selective uptake of a recombinant C3-fusion toxin into the cytosol of macrophages. CONCLUSIONS/SIGNIFICANCE: In summary, we demonstrated that C3bot1E174Q can be used as a delivery system for fast, selective and specific transport of enzymes into the cytosol of living macrophages. Therefore, C3-based fusion toxins can represent valuable molecular tools in experimental macrophage pharmacology and cell biology as well as attractive candidates to develop new therapeutic approaches against macrophage-associated diseases.

  12. 12 CFR 563c.3 - Qualification of public accountant.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Qualification of public accountant. 563c.3... REQUIREMENTS Form and Content of Financial Statements § 563c.3 Qualification of public accountant. (See also 17 CFR 210.2-01.) The term “qualified public accountant” means a certified public accountant or licensed...

  13. Ultrathin g-C3N4 films supported on Attapulgite nanofibers with enhanced photocatalytic performance

    Science.gov (United States)

    Xu, Yongshuai; Zhang, Lili; Yin, Minghui; Xie, Dengyu; Chen, Jiaqi; Yin, Jingzhou; Fu, Yongsheng; Zhao, Pusu; Zhong, Hui; Zhao, Yijiang; Wang, Xin

    2018-05-01

    A novel visible-light-responsive photocatalyst is fabricated by introducing g-C3N4 ultrathin films onto the surface of attapulgite (ATP) via a simple in-situ depositing technique, in which ATP was pre-grafted using (3-Glycidyloxypropyl) trimethoxysilane (KH560) as the surfactant. A combination of XRD, FT-IR, BET, XPS, UV-vis, TEM and SEM techniques are utilized to characterize the composition, morphology and optical properties of the products. The results show that with the help of KH560, g-C3N4 presented as ultrathin layer is uniformly loaded onto the surface of ATP by forming a new chemical bond (Sisbnd Osbnd C). Comparing with g-C3N4 and ATP, ATP/g-C3N4 exhibits remarkably enhanced visible-light photocatalytic activity in degradation of methyl orange (MO) because of its high surface area, appropriate band gap and the synergistic effect between g-C3N4 and ATP. To achieve the best photocatalyst, the ratio of g-C3N4 was adjusted by controlling the mass portion between ATP-KH560 and melamine (r = m (ATP-KH560)/m (melamine)). The highest decomposition rate of methyl orange (MO) was 96.06% when r = 0.5 and this degradation efficiency remained unchanged after 4 cycles, which is 10 times as that of pure g-C3N4 particles. Possible photocatalytic mechanism is presented.

  14. Ferromagnetic Levan Composite: An Affinity Matrix to Purify Lectin

    Directory of Open Access Journals (Sweden)

    Renata Angeli

    2009-01-01

    Full Text Available A simple and inexpensive procedure used magnetite and levan to synthesize a composite recovered by a magnetic field. Lectins from Canavalia ensiformis (Con A and Cratylia mollis (Cramoll 1 and Cramoll 1,4 did bind specifically to composite. The magnetic property of derivative favored washing out contaminating proteins and recovery of pure lectins with glucose elution. Cramoll 1 was purified by this affinity binding procedure in two steps instead of a previous three-step protocol with ammonium sulfate fractionation, affinity chromatography on Sephadex G-75, and ion exchange chromatography through a CM-cellulose column.

  15. Purification and characterization of a new type lactose-binding Ulex europaeus lectin by affinity chromatography.

    Science.gov (United States)

    Konami, Y; Yamamoto, K; Osawa, T

    1991-02-01

    A new type lactose-binding lectin was purified from extracts of Ulex europaeus seeds by affinity chromatography on a column of galactose-Sepharose 4B, followed by gel filtration on Sephacryl S-300. This lectin, designated as Ulex europaeus lectin III (UEA-III), was found to be inhibited by lactose. The dimeric lectin is a glycoprotein with a molecular mass of 70,000 Da; it consists of two apparently identical subunits of a molecular mass of 34,000 Da. Compositional analysis showed that this lectin contains 30% carbohydrate and a large amount of aspartic acid, serine and valine, but no sulfur-containing amino acids. The N-terminal amino-acid sequences of L-fucose-binding Ulex europaeus lectin I (UEA-I) and di-N-acetylchitobiose-binding Ulex europaeus lectin II (UEA-II), both of which we have already purified and characterized, and that of UEA-III were determined and compared.

  16. Synthesis of g-C3N4/Ag3PO4 heterojunction with enhanced photocatalytic performance

    International Nuclear Information System (INIS)

    He, Peizhi; Song, Limin; Zhang, Shujuan; Wu, Xiaoqing; Wei, Qingwu

    2014-01-01

    Graphical abstract: g-C 3 N 4 /Ag 3 PO 4 heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The results show that g-C 3 N 4 /Ag 3 PO 4 possesses a much higher activity for the decomposition of RhB than that of the pure Ag 3 PO 4 particles. The most mechanism is that g-C 3 N 4 /Ag 3 PO 4 heterojunction photocatalyst can efficiently separate the photogenerated electron–hole pairs, enhancing the photocatalytic activity of g-C 3 N 4 /Ag 3 PO 4 composites. - Highlights: • g-C 3 N 4 /Ag 3 PO 4 heterojunction showed much higher activity than that of Ag 3 PO 4 . • The high activity could be attributed to g-C 3 N 4 for modifying Ag 3 PO 4 . • More ·OH radicals may be significant reason to improve Ag 3 PO 4 activity. - Abstract: g-C 3 N 4 /Ag 3 PO 4 heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UV–vis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C 3 N 4 /Ag 3 PO 4 decomposed RhB more effectively than the pure Ag 3 PO 4 particles did, and 2 wt.% g-C 3 N 4 had the highest activity. Furthermore, 2 wt.% g-C 3 N 4 /Ag 3 PO 4 degraded high-concentration RhB more potently than unmodified Ag 3 PO 4 did, probably because g-C 3 N 4 /Ag 3 PO 4 heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electron–hole pairs

  17. A potent complement factor C3 specific nanobody inhibiting multiple functions in the alternative pathway of human and murine complement

    DEFF Research Database (Denmark)

    Jensen, Rasmus K; Pihl, Rasmus; Gadeberg, Trine A F

    2018-01-01

    The complement system is a complex, carefully regulated proteolytic cascade for which suppression of aberrant activation is of increasing clinical relevance and inhibition of the complement alternative pathway is a subject of intense research. Here, we describe the nanobody hC3Nb1 that binds...... to multiple functional states of C3 with sub-nanomolar affinity. The nanobody causes a complete shutdown of alternative pathway activity in human and murine serum when present in concentrations comparable to C3, and hC3Nb1 is shown to prevent both proconvertase assembly as well as binding of the C3 substrate...... to C3 convertases. Our crystal structure of the C3b-hC3Nb1 complex and functional experiments demonstrate that proconvertase formation is blocked by steric hindrance between the nanobody and an Asn-linked glycan on complement factor B. In addition, hC3Nb1 is shown to prevent factor H binding to C3b...

  18. The galactose-binding lectin isolated from Bauhinia bauhinioides Mart seeds inhibits neutrophil rolling and adhesion via primary cytokines.

    Science.gov (United States)

    Girão, Deysen Kerlla Fernandes Bezerra; Cavada, Benildo Sousa; de Freitas Pires, Alana; Martins, Timna Varela; Franco, Álvaro Xavier; Morais, Cecília Mendes; Santiago do Nascimento, Kyria; Delatorre, Plinio; da Silva, Helton Colares; Nagano, Celso Shiniti; Assreuy, Ana Maria Sampaio; Soares, Pedro Marcos Gomes

    2015-05-01

    In this study, the amino acid sequence and anti-inflammatory effect of Bauhinia bauhinioides (BBL) lectin were evaluated. Tandem mass spectrometry revealed that BBL possesses 86 amino acid residues. BBL (1 mg/kg) intravenously injected in rats 30 min prior to inflammatory stimuli inhibited the cellular edema induced by carrageenan in only the second phase (21% - 3 h, 19% - 4 h) and did not alter the osmotic edema induced by dextran. BBL also inhibited carrageenan peritoneal neutrophil migration (51%), leukocyte rolling (58%) and adhesion (68%) and the neutrophil migration induced by TNF-α (64%). These effects were reversed by the association of BBL with galactose, demonstrating that the carbohydrate-binding domain is essential for lectin activity. In addition, BBL reduced myeloperoxidase activity (84%) and TNF-α (68%) and IL1-β (47%) levels. In conclusion, the present investigation demonstrated that BBL contains highly homologous isolectins, resulting in a total of 86 amino acid residues, and exhibits anti-inflammatory activity by inhibiting neutrophil migration by reducing TNF-α and IL1-β levels via the lectin domain. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Mitogenic Properties Of Lectin From Mucuna Sloanei Seed Extracts ...

    African Journals Online (AJOL)

    (p<0.05) increases in the values of the immunological parameters relative to those seen in the controls. This study, suggest that the isolated lectin from mucona sloanei seeds possesses mitogenic properties, and may be useful in the diagnosis and treatment of certain diseases such as blood typing disorders and obesity.

  20. Alternate gram staining technique using a fluorescent lectin.

    Science.gov (United States)

    Sizemore, R K; Caldwell, J J; Kendrick, A S

    1990-01-01

    Fluorescence-labeled wheat germ agglutinin binds specifically to N-acetylglucosamine in the outer peptidoglycan layer of gram-positive bacteria. The peptidoglycan layer of gram-negative bacteria is covered by a membrane and is not labeled by the lectin. By exploiting this phenomenon, an alternative Gram staining technique has been developed. Images PMID:1697149

  1. Tetranectin, a trimeric plasminogen-binding C-type lectin

    DEFF Research Database (Denmark)

    Holtet, T L; Graversen, Jonas Heilskov; Clemmensen, I

    1997-01-01

    -linking analysis and SDS-PAGE to be a homo-trimer in solution as are other known members of the collectin family of C-type lectins. Biochemical evidence is presented showing that an N-terminal domain encoded within exons 1 and 2 of the tetranectin gene is necessary and sufficient to govern subunit trimerization....

  2. Cancer Biomarker Discovery: Lectin-Based Strategies Targeting Glycoproteins

    Directory of Open Access Journals (Sweden)

    David Clark

    2012-01-01

    Full Text Available Biomarker discovery can identify molecular markers in various cancers that can be used for detection, screening, diagnosis, and monitoring of disease progression. Lectin-affinity is a technique that can be used for the enrichment of glycoproteins from a complex sample, facilitating the discovery of novel cancer biomarkers associated with a disease state.

  3. Clinical manifestations of mannan-binding lectin deficiency

    DEFF Research Database (Denmark)

    Thiel, S; Frederiksen, P D; Jensenius, Jens Christian

    2006-01-01

    Mannan-binding lectin (MBL) is a plasma protein of the innate immune system with the ability to initiate antimicrobial and inflammatory actions. MBL deficiency is common. More than 10% of the general population may, depending on definition, be classified as MBL deficient, underlining the redundan...

  4. The distribution of lectin receptor sites in human breast lesions.

    Science.gov (United States)

    Skutelsky, E; Hoenig, S; Griffel, B; Alroy, J

    1988-08-01

    Conflicting data regarding the status of A, B, H and T antigens in epithelium of normal, mastopathies, fibroadenomas and carcinomas of the breast stimulated us to re-examine the carbohydrate residues in these condition. Currently, we extended the number of carbohydrate residues studied by using ten different biotinylated lectins as probes and avidin-biotin-peroxidase complex (ABC) as a visualant. In addition, the pattern of lectin staining of cancerous cells in primary and metastatic sites was compared. In primary and metastatic breast carcinomas, lectin receptor sites were stained more intensely with Concanavalia ensiformi agglutinin (*Con A), Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA), than in normal breast, in mastopathies or in fibroadenomas. Cryptic receptor sites for peanut agglutinin (PNA) were stained in all cases of breast carcinomas, while free PNA sites stained only in a few cases of well-differentiated carcinomas. Receptors sites for Ulex europaeus agglutinin-I (UEA-I) stained non-malignant epithelium of patients with blood group H but did not stain malignant cells. The results show significant differences in lectin-binding patterns and staining intensities between normal and non-malignant, and malignant epithelial breast cells. Furthermore, these results indicate that in malignant cells, there is an increased content of sialic acid-rich carbohydrates but not of asialylated glycoconjugates.

  5. Mannan-binding lectin in astma and allergy

    DEFF Research Database (Denmark)

    Kaur, S.; Thiel, Steffen; Sarma, P.U.

    2006-01-01

    Mannan-binding lectin (MBL) is a vital and versatile component of innate immunity. It is present in serum and may bind to a plethora of microbial pathogens and mediate opsonization of these by complement-dependent and/or independent mechanisms. Low-MBL levels in serum, attributed to certain genet...

  6. Presenting Precision Glycomacromolecules on Gold Nanoparticles for Increased Lectin Binding

    Directory of Open Access Journals (Sweden)

    Sophia Boden

    2017-12-01

    Full Text Available Glyco-functionalized gold nanoparticles have great potential as biosensors and as inhibitors due to their increased binding to carbohydrate-recognizing receptors such as the lectins. Here we apply previously developed solid phase polymer synthesis to obtain a series of precision glycomacromolecules that allows for straightforward variation of their chemical structure as well as functionalization of gold nanoparticles by ligand exchange. A novel building block is introduced allowing for the change of spacer building blocks within the macromolecular scaffold going from an ethylene glycol unit to an aliphatic spacer. Furthermore, the valency and overall length of the glycomacromolecule is varied. All glyco-functionalized gold nanoparticles show high degree of functionalization along with high stability in buffer solution. Therefore, a series of measurements applying UV-Vis spectroscopy, dynamic light scattering (DLS and surface plasmon resonance (SPR were performed studying the aggregation behavior of the glyco-functionalized gold nanoparticles in presence of model lectin Concanavalin A. While the multivalent presentation of glycomacromolecules on gold nanoparticles (AuNPs showed a strong increase in binding compared to the free ligands, we also observed an influence of the chemical structure of the ligand such as its valency or hydrophobicity on the resulting lectin interactions. The straightforward variation of the chemical structure of the precision glycomacromolecule thus gives access to tailor-made glyco-gold nanoparticles (glyco-AuNPs and fine-tuning of their lectin binding properties.

  7. Cereal n-glycoproteins enrichment by lectin affinity monolithic chromatography

    Czech Academy of Sciences Publication Activity Database

    Flodrová, Dana; Bobálová, Janette; Laštovičková, Markéta

    2016-01-01

    Roč. 44, č. 2 (2016), s. 286-297 ISSN 0133-3720 R&D Projects: GA ČR(CZ) GPP503/12/P395 Institutional support: RVO:68081715 Keywords : barley * wheat * glycoprotein * mass spectrometry * lectin chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.496, year: 2016

  8. Signalling through C-type lectin receptors: shaping immune responses

    NARCIS (Netherlands)

    Geijtenbeek, Teunis B. H.; Gringhuis, Sonja I.

    2009-01-01

    C-type lectin receptors (CLRs) expressed by dendritic cells are crucial for tailoring immune responses to pathogens. Following pathogen binding, CLRs trigger distinct signalling pathways that induce the expression of specific cytokines which determine T cell polarization fates. Some CLRs can induce

  9. Momordica charantia seed lectin: toxicity, bacterial agglutination and antitumor properties.

    Science.gov (United States)

    Kabir, Syed Rashel; Nabi, Md Mahamodun; Nurujjaman, Md; Abu Reza, Md; Alam, A H M Khurshid; Uz Zaman, Rokon; Khalid-Bin-Ferdaus, Khandaker Md; Amin, Ruhul; Khan, Md Masudul Hasan; Hossain, Md Anowar; Uddin, Md Salim; Mahmud, Zahid Hayat

    2015-03-01

    In last three decades, several studies were carried out on the D-galactose-specific lectin of Momordica charantia seeds (MCL). In the present study, in vitro growth inhibition (8-23 %) at different concentrations (6-24 μg/ml) of MCL was observed against Ehrlich ascites carcinoma (EAC) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. MCL also showed 28, 45, and 75 % growth inhibitions against EAC cells when administered 1.2, 2.0, and 2.8 mg/kg/day (i.p.), respectively for five consequent days in vivo in mice. After lectin treatment, the level of red blood cell and hemoglobin was increased significantly with the decrease of white blood cell and maintained the normal level when compared with EAC-bearing control and normal mice without EAC cells. Although MCL caused cell cycle arrest at G0/G1 phase of EAC cells, any irregular shape or apoptotic morphological alterations in the lectin-treated EAC cells was not observed by an optical and fluorescence microscope. Lectin showed toxicity against brine shrimp nauplii with an LC50 value of 49.7 μg/ml. Four out of seven pathogenic bacteria were agglutinated by MCL in the absence of inhibitory sugar D-lactose/D-galactose. In conclusion, MCL showed strong cytotoxic effect and therefore can be used as a potent anticancer chemotherapeutic agent.

  10. Galactose/N-acetylgalactosamine lectin: the coordinator of host cell ...

    Indian Academy of Sciences (India)

    Unknown

    Involvement of the lectin ... tion of the extra-cellular matrix (DeMeester et al 1990). The goal of this review is to ... E. histolytica molecules discovered that bind these resi- dues are the ..... Fas-dependent, non-tumor necrosis factor alpha depen-.

  11. Photocatalytic degradation of methylene blue by C 3 N 4 /ZnO

    Indian Academy of Sciences (India)

    The photocatalytic activities of prepared samples were investigated under the illumination of blacklight and fluorescent lamps as the low wattage light source. The C 3 N 4 /ZnO showed a better photocatalytic activity than ZnO to degrade a methylene blue (MB) dye solution using blacklight lamps, but there is no significant ...

  12. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway.

    Science.gov (United States)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine; Garred, Peter

    2017-01-01

    The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition molecules that bind specific patterns on microbial surfaces, a group of associated proteases that initiates the complement cascade, and a group of proteins that interact in proteolytic complexes or the terminal pore-forming complex. In addition, various regulatory proteins are important for controlling the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system. Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination.

  13. C3b/iC3b deposition on Streptococcus pneumoniae is not affected by HIV infection.

    Directory of Open Access Journals (Sweden)

    Catherine Hyams

    2010-01-01

    Full Text Available Streptococcus pneumoniae is a common cause of infection in both HIV positive patients and those with complement deficiencies. We hypothesised that HIV positive individuals might exhibit reduced opsonisation of pneumococcus with complement due to reduced levels of S. pneumoniae specific IgG. We discovered no difference in C3 deposition on S. pneumoniae between HIV positive or negative individuals, and furthermore C3 deposition remained unchanged as HIV progressed towards AIDS. We found no correlation between C3 deposition on S. pneumoniae and CD4 cell count in HIV infected individuals. Hence we have demonstrated no failure of complement immunity in HIV positive patients.

  14. Engineering of a Potent Recombinant Lectin-Toxin Fusion Protein to Eliminate Human Pluripotent Stem Cells.

    Science.gov (United States)

    Tateno, Hiroaki; Saito, Sayoko

    2017-07-10

    The use of human pluripotent stem cells (hPSCs) such as human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) in regenerative medicine is hindered by their tumorigenic potential. Previously, we developed a recombinant lectin-toxin fusion protein of the hPSC-specific lectin rBC2LCN, which has a 23 kDa catalytic domain (domain III) of Pseudomonas aeruginosa exotoxin A (rBC2LCN-PE23). This fusion protein could selectively eliminate hPSCs following its addition to the cell culture medium. Here we conjugated rBC2LCN lectin with a 38 kDa domain of exotoxin A containing domains Ib and II in addition to domain III (PE38). The developed rBC2LCN-PE38 fusion protein could eliminate 50% of 201B7 hPSCs at a concentration of 0.003 μg/mL (24 h incubation), representing an approximately 556-fold higher activity than rBC2LCN-PE23. Little or no effect on human fibroblasts, human mesenchymal stem cells, and hiPSC-derived hepatocytes was observed at concentrations lower than 1 μg/mL. Finally, we demonstrate that rBC2LCN-PE38 selectively eliminates hiPSCs from a mixed culture of hiPSCs and hiPSC-derived hepatocytes. Since rBC2LCN-PE38 can be prepared from soluble fractions of E. coli culture at a yield of 9 mg/L, rBC2LCN-PE38 represents a practical reagent to remove human pluripotent stem cells residing in cultured cells destined for transplantation.

  15. An Ixodes ricinus Tick Salivary Lectin Pathway Inhibitor Protects Borrelia burgdorferi sensu lato from Human Complement.

    Science.gov (United States)

    Wagemakers, Alex; Coumou, Jeroen; Schuijt, Tim J; Oei, Anneke; Nijhof, Ard M; van 't Veer, Cornelis; van der Poll, Tom; Bins, Adriaan D; Hovius, Joppe W R

    2016-04-01

    We previously identified tick salivary lectin pathway inhibitor (TSLPI) in Ixodes scapularis, a vector for Borrelia burgdorferi sensu stricto (s.s.) in North America. TSLPI is a salivary protein facilitating B. burgdorferi s.s. transmission and acquisition by inhibiting the host lectin complement pathway through interference with mannose binding lectin (MBL) activity. Since Ixodes ricinus is the predominant vector for Lyme borreliosis in Europe and transmits several complement sensitive B. burgdorferi sensu lato (s.l.) strains, we aimed to identify, describe, and characterize the I. ricinus ortholog of TSLPI. We performed (q)PCRs on I. ricinus salivary gland cDNA to identify a TSLPI ortholog. Next, we generated recombinant (r)TSLPI in a Drosophila expression system and examined inhibition of the MBL complement pathway and complement-mediated killing of B. burgdorferi s.l. in vitro. We identified a TSLPI ortholog in I. ricinus salivary glands with 93% homology at the RNA and 89% at the protein level compared to I. scapularis TSLPI, which was upregulated during tick feeding. In silico analysis revealed that TSLPI appears to be part of a larger family of Ixodes salivary proteins among which I. persulcatus basic tail salivary proteins and I. scapularis TSLPI and Salp14. I. ricinus rTSLPI inhibited the MBL complement pathway and protected B. burgdorferi s.s. and Borrelia garinii from complement-mediated killing. We have identified a TSLPI ortholog, which protects B. burgdorferi s.l. from complement-mediated killing in I. ricinus, the major vector for tick-borne diseases in Europe.

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

    Science.gov (United States)

    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.

  17. Association of Lectin Pathway Protein Levels and Genetic Variants Early after Injury with Outcomes after Severe Traumatic Brain Injury: A Prospective Cohort Study.

    Science.gov (United States)

    Osthoff, Michael; Walder, Bernhard; Delhumeau, Cécile; Trendelenburg, Marten; Turck, Natacha

    2017-09-01

    The lectin pathway of the complement system has been implicated in secondary ischemic/inflammatory injury after traumatic brain injury (TBI). However, previous experimental studies have yielded conflicting results, and human studies are scarce. In this exploratory study, we investigated associations of several lectin pathway proteins early after injury and single-nucleotide polymorphisms (SNP) with outcomes after severe TBI (mortality at 14 days [primary outcome] and consciousness assessed with the Glasgow Coma Scale [GCS] at 14 days, disability assessed with the Glasgow Outcome Scale Extended [GOSE] at 90 days). Forty-four patients with severe TBI were included. Plasma levels of lectin pathway proteins were sampled at 6, 12, 24, and 48 h after injury and eight mannose-binding lectin (MBL) and ficolin (FCN)2 SNPs were analyzed by enzyme-linked immunosorbent assay (ELISA) and genotyping, respectively. Plasma protein levels were stable with only a slight increase in mannose-binding protein-associated serine protease (MASP)-2 and FCN2 levels after 48 h (p GOSE 1-4) at 90 days (p GOSE score < 4 at 90 days after adjustment (odds ratio 3.46 [95% confidence interval 1.12-10.68] per 100 ng/mL increase, p = 0.03). No association was observed between the lectin pathway of the complement system and 14 day mortality or 14 day consciousness. However, higher plasma FCN2, FCN3, and, in particular, MASP-2 levels early after injury were associated with an unfavorable outcome at 90 days (death, vegetative state, and severe disability) which may be related to an increased activation of the lectin pathway.

  18. Mannan-binding lectin MBL2 gene polymorphism in chronic hepatitis C: association with the severity of liver fibrosis and response to interferon therapy

    DEFF Research Database (Denmark)

    Alves Pedroso, ML; Boldt, AB; Pereira-Ferrari, L

    2008-01-01

    Hepatitis C virus (HCV) is a major cause of hepatic disease and of liver transplantation worldwide. Mannan-binding lectin (MBL), encoded by the MBL2 gene, can have an important role as an opsonin and complement activating molecule in HCV persistence and liver injury. We assessed the MBL2...

  19. Novel β-C3N4/CuO nanoflakes: facile synthesis and unique photocatalytic performance

    Science.gov (United States)

    Zou, Lan-Rong; Huang, Gui-Fang; Li, Dong-Feng; Tian, Qing-Nan; Yang, Ke; Si, Yuan; Chang, Shengli; Zhang, Xue-Ao; Huang, Wei-Qing

    2017-09-01

    For the first time, novel β-C3N4/CuO composites with superior photocatalytic activity are successfully fabricated via a facile reflux method followed by a thermal process. The morphologies, particle size and microstructure of the synthesized β-C3N4/CuO composites largely depended upon copper chloride and the volume ratio of V water:V ethanol in the mixed precursors. The fabricated β-C3N4/CuO nanoflakes exhibited obviously enhanced visible light photocatalytic activity for the degradation of methylene blue (MB) with an  ˜3.4 and 1.9 fold increase in efficiency over that of pure g-C3N4 and commercial P25, respectively. The β-C3N4/CuO composite photocatalyst also showed photocatalytic activity for the degradation of methyl orange (MO). Moreover, the β-C3N4/CuO nanoflakes showed almost no loss of photocatalytic activity after three recycles of the degradation of the MB. A multiple synergetic mechanism in β-C3N4/CuO nanoflakes, which is featured by the highly reactive {0 0 2} facets, exposed many active sites of nanoflakes and the efficient charge separation are proposed to account for the distinguished photocatalytic activity. This work provides a facile and cost-effective strategy for designing novel β-C3N4/CuO photocatalysts for application in environmental purification.

  20. Anthracycline resistance mediated by reductive metabolism in cancer cells: The role of aldo-keto reductase 1C3

    International Nuclear Information System (INIS)

    Hofman, Jakub; Malcekova, Beata; Skarka, Adam; Novotna, Eva; Wsol, Vladimir

    2014-01-01

    Pharmacokinetic drug resistance is a serious obstacle that emerges during cancer chemotherapy. In this study, we investigated the possible role of aldo-keto reductase 1C3 (AKR1C3) in the resistance of cancer cells to anthracyclines. First, the reducing activity of AKR1C3 toward anthracyclines was tested using incubations with a purified recombinant enzyme. Furthermore, the intracellular reduction of daunorubicin and idarubicin was examined by employing the transfection of A549, HeLa, MCF7 and HCT 116 cancer cells with an AKR1C3 encoding vector. To investigate the participation of AKR1C3 in anthracycline resistance, we conducted MTT cytotoxicity assays with these cells, and observed that AKR1C3 significantly contributes to the resistance of cancer cells to daunorubicin and idarubicin, whereas this resistance was reversible by the simultaneous administration of 2′-hydroxyflavanone, a specific AKR1C3 inhibitor. In the final part of our work, we tracked the changes in AKR1C3 expression after anthracycline exposure. Interestingly, a reciprocal correlation between the extent of induction and endogenous levels of AKR1C3 was recorded in particular cell lines. Therefore, we suggest that the induction of AKR1C3 following exposure to daunorubicin and idarubicin, which seems to be dependent on endogenous AKR1C3 expression, eventually might potentiate an intrinsic resistance given by the normal expression of AKR1C3. In conclusion, our data suggest a substantial impact of AKR1C3 on the metabolism of daunorubicin and idarubicin, which affects their pharmacokinetic and pharmacodynamic behavior. In addition, we demonstrate that the reduction of daunorubicin and idarubicin, which is catalyzed by AKR1C3, contributes to the resistance of cancer cells to anthracycline treatment. - Highlights: • Metabolism of anthracyclines by AKR1C3 was studied at enzyme and cellular levels. • Anthracycline resistance mediated by AKR1C3 was demonstrated in cancer cells. • Induction of AKR1C3

  1. Eculizumab for dense deposit disease and C3 glomerulonephritis.

    Science.gov (United States)

    Bomback, Andrew S; Smith, Richard J; Barile, Gaetano R; Zhang, Yuzhou; Heher, Eliot C; Herlitz, Leal; Stokes, M Barry; Markowitz, Glen S; D'Agati, Vivette D; Canetta, Pietro A; Radhakrishnan, Jai; Appel, Gerald B

    2012-05-01

    The principle defect in dense deposit disease and C3 glomerulonephritis is hyperactivity of the alternative complement pathway. Eculizumab, a monoclonal antibody that binds to C5 to prevent formation of the membrane attack complex, may prove beneficial. In this open-label, proof of concept efficacy and safety study, six subjects with dense deposit disease or C3 glomerulonephritis were treated with eculizumab every other week for 1 year. All had proteinuria >1 g/d and/or AKI at enrollment. Subjects underwent biopsy before enrollment and repeat biopsy at the 1-year mark. The subjects included three patients with dense deposit disease (including one patient with recurrent dense deposit disease in allograft) and three patients with C3 glomerulonephritis (including two patients with recurrent C3 glomerulonephritis in allograft). Genetic and complement function testing revealed a mutation in CFH and MCP in one subject each, C3 nephritic factor in three subjects, and elevated levels of serum membrane attack complex in three subjects. After 12 months, two subjects showed significantly reduced serum creatinine, one subject achieved marked reduction in proteinuria, and one subject had stable laboratory parameters but histopathologic improvements. Elevated serum membrane attack complex levels normalized on therapy and paralleled improvements in creatinine and proteinuria. Clinical and histopathologic data suggest a response to eculizumab in some but not all subjects with dense deposit disease and C3 glomerulonephritis. Elevation of serum membrane attack complex before treatment may predict response. Additional research is needed to define the subgroup of dense deposit disease/C3 glomerulonephritis patients in whom eculizumab therapy can be considered.

  2. Development of Seaweed-based Biopolymers for Edible Films and Lectins

    Science.gov (United States)

    Praseptiangga, D.

    2017-04-01

    Marine macroalgae (seaweeds) as one of important groups of biopolymers play an important role in human life. Biopolymers have been studied regarding their film-forming properties to produce edible films intended as food packaging and active ingredient carriers. Edible film, a thin layer or which is an integral part of food and can be eaten together with, have been used to avoid food quality deterioration due to physico-chemical changes, texture changes, or chemical reactions. Film-forming materials can be utilized individually or as mixed composite blends. Proteins and polysaccharides used for their mechanical and structural properties, and hydrophobic substances (lipids, essential oils, and emulsifiers) to provide good moisture barrier properties. In addition, bioactive substances from marine natural products, including seaweeds, have been explored for being used in the fields of medicine, food science, pharmaceutical science, biochemistry, and glycobiology. Among them, lectins or carbohydrate-binding proteins from seaweeds have recently been remarked. Lectins (hemagglutinins) are widely distributed in nature and also good candidates in such prospecting of seaweeds. They are useful as convenient tools to discriminate differences in carbohydrate structures and reveal various biological activities through binding and interacting to carbohydrates, suggesting that they are promising candidates for medicinal and clinical application.

  3. Functional and physical molecular size of the chicken hepatic lectin determined by radiation inactivation and sedimentation equilibrium analysis

    International Nuclear Information System (INIS)

    Steer, C.J.; Osborne, J.C. Jr.; Kempner, E.S.

    1990-01-01

    Radiation inactivation and sedimentation equilibrium analysis were used to determine the functional and physical size of the chicken hepatic membrane receptor that binds N-acetylglucosamine-terminated glycoproteins. Purified plasma membranes from chicken liver were irradiated with high energy electrons and assayed for 125I-agalactoorosomucoid binding. Increasing the dose of ionizing radiation resulted in a monoexponential decay in binding activity due to a progressive loss of binding sites. The molecular mass of the chicken lectin, determined in situ by target analysis, was 69,000 +/- 9,000 Da. When the same irradiated membranes were solubilized in Brij 58 and assayed, the binding protein exhibited a target size of 62,000 +/- 4,000 Da; in Triton X-100, the functional size of the receptor was 85,000 +/- 10,000 Da. Sedimentation equilibrium measurements of the purified binding protein yielded a lower limit molecular weight of 79,000 +/- 7,000. However, the solubilized lectin was detected as a heterogeneous population of oligomers with molecular weights as high as 450,000. Addition of calcium or calcium plus N-acetylglucosamine decreased the higher molecular weight species, but the lower limit molecular weights remained invariant. Similar results were determined when the chicken lectin was solubilized in Brij 58, C12E9, or 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonic acid (CHAPS). Results from the present study suggest that in the plasma membrane, the functional species of the chicken hepatic lectin exists as a trimer. However, in detergent solution, the purified receptor forms a heterogeneous population of irreversible oligomers that exhibit binding activity proportional to size

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

    Science.gov (United States)

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

    2015-12-10

    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.

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

    Directory of Open Access Journals (Sweden)

    Jingqun Ao

    2015-12-01

    Full Text Available 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.

  6. The Phosphatidylinositol (3,4,5)-Trisphosphate-dependent Rac Exchanger 1·Ras-related C3 Botulinum Toxin Substrate 1 (P-Rex1·Rac1) Complex Reveals the Basis of Rac1 Activation in Breast Cancer Cells.

    Science.gov (United States)

    Lucato, Christina M; Halls, Michelle L; Ooms, Lisa M; Liu, Heng-Jia; Mitchell, Christina A; Whisstock, James C; Ellisdon, Andrew M

    2015-08-21

    The P-Rex (phosphatidylinositol (3,4,5)-trisphosphate (PIP3)-dependent Rac exchanger) family (P-Rex1 and P-Rex2) of the Rho guanine nucleotide exchange factors (Rho GEFs) activate Rac GTPases to regulate cell migration, invasion, and metastasis in several human cancers. The family is unique among Rho GEFs, as their activity is regulated by the synergistic binding of PIP3 and Gβγ at the plasma membrane. However, the molecular mechanism of this family of multi-domain proteins remains unclear. We report the 1.95 Å crystal structure of the catalytic P-Rex1 DH-PH tandem domain in complex with its cognate GTPase, Rac1 (Ras-related C3 botulinum toxin substrate-1). Mutations in the P-Rex1·Rac1 interface revealed a critical role for this complex in signaling downstream of receptor tyrosine kinases and G protein-coupled receptors. The structural data indicated that the PIP3/Gβγ binding sites are on the opposite surface and markedly removed from the Rac1 interface, supporting a model whereby P-Rex1 binding to PIP3 and/or Gβγ releases inhibitory C-terminal domains to expose the Rac1 binding site. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

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

    Directory of Open Access Journals (Sweden)

    Matthew Brudner

    Full Text Available 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

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

    Science.gov (United States)

    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

  9. Microbial F-type lectin domains with affinity for blood group antigens.

    Science.gov (United States)

    Mahajan, Sonal; Khairnar, Aasawari; Bishnoi, Ritika; Ramya, T N C

    2017-09-23

    F-type lectins are fucose binding lectins with characteristic fucose binding and calcium binding motifs. Although they occur with a selective distribution in viruses, prokaryotes and eukaryotes, most biochemical studies have focused on vertebrate F-type lectins. Recently, using sensitive bioinformatics search techniques on the non-redundant database, we had identified many microbial F-type lectin domains with diverse domain organizations. We report here the biochemical characterization of F-type lectin domains from Cyanobium sp. PCC 7001, Myxococcus hansupus and Leucothrix mucor. We demonstrate that while all these three microbial F-type lectin domains bind to the blood group H antigen epitope on fucosylated glycans, there are fine differences in their glycan binding specificity. Cyanobium sp. PCC 7001 F-type lectin domain binds exclusively to extended H type-2 motif, Myxococcus hansupus F-type lectin domain binds to B, H type-1 and Lewis b motifs, and Leucothrix mucor F-type lectin domain binds to a wide range of fucosylated glycans, including A, B, H and Lewis antigens. We believe that these microbial lectins will be useful additions to the glycobiologist's toolbox for labeling, isolating and visualizing glycans. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Complement C3 deficiency attenuates chronic hypoxia-induced pulmonary hypertension in mice.

    Directory of Open Access Journals (Sweden)

    Eileen M Bauer

    Full Text Available Evidence suggests a role of both innate and adaptive immunity in the development of pulmonary arterial hypertension. The complement system is a key sentry of the innate immune system and bridges innate and adaptive immunity. To date there are no studies addressing a role for the complement system in pulmonary arterial hypertension.Immunofluorescent staining revealed significant C3d deposition in lung sections from IPAH patients and C57Bl6/J wild-type mice exposed to three weeks of chronic hypoxia to induce pulmonary hypertension. Right ventricular systolic pressure and right ventricular hypertrophy were increased in hypoxic vs. normoxic wild-type mice, which were attenuated in C3-/- hypoxic mice. Likewise, pulmonary vascular remodeling was attenuated in the C3-/- mice compared to wild-type mice as determined by the number of muscularized peripheral arterioles and morphometric analysis of vessel wall thickness. The loss of C3 attenuated the increase in interleukin-6 and intracellular adhesion molecule-1 expression in response to chronic hypoxia, but not endothelin-1 levels. In wild-type mice, but not C3-/- mice, chronic hypoxia led to platelet activation as assessed by bleeding time, and flow cytometry of platelets to determine cell surface P-selectin expression. In addition, tissue factor expression and fibrin deposition were increased in the lungs of WT mice in response to chronic hypoxia. These pro-thrombotic effects of hypoxia were abrogated in C3-/- mice.Herein, we provide compelling genetic evidence that the complement system plays a pathophysiologic role in the development of PAH in mice, promoting pulmonary vascular remodeling and a pro-thrombotic phenotype. In addition we demonstrate C3d deposition in IPAH patients suggesting that complement activation plays a role in the development of PAH in humans.

  11. Reduced graphene oxide wrapped Cu2O supported on C3N4: An efficient visible light responsive semiconductor photocatalyst

    Directory of Open Access Journals (Sweden)

    S. Ganesh Babu

    2015-10-01

    Full Text Available Herein, Cu2O spheres were prepared and encapsulated with reduced graphene oxide (rGO. The Cu2O–rGO–C3N4 composite covered the whole solar spectrum with significant absorption intensity. rGO wrapped Cu2O loading caused a red shift in the absorption with respect to considering the absorption of bare C3N4. The photoluminescence study confirms that rGO exploited as an electron transport layer at the interface of Cu2O and C3N4 heterojunction. Utmost, ∼2 fold synergistic effect was achieved with Cu2O–rGO–C3N4 for the photocatalytic reduction of 4-nitrophenol to 4-aminophenol in comparison with Cu2O–rGO and C3N4. The Cu2O–rGO–C3N4 photocatalyst was reused for four times without loss in its activity.

  12. Reduced graphene oxide wrapped Cu2O supported on C3N4: An efficient visible light responsive semiconductor photocatalyst

    Science.gov (United States)

    Ganesh Babu, S.; Vinoth, R.; Surya Narayana, P.; Bahnemann, Detlef; Neppolian, B.

    2015-10-01

    Herein, Cu2O spheres were prepared and encapsulated with reduced graphene oxide (rGO). The Cu2O-rGO-C3N4 composite covered the whole solar spectrum with significant absorption intensity. rGO wrapped Cu2O loading caused a red shift in the absorption with respect to considering the absorption of bare C3N4. The photoluminescence study confirms that rGO exploited as an electron transport layer at the interface of Cu2O and C3N4 heterojunction. Utmost, ˜2 fold synergistic effect was achieved with Cu2O-rGO-C3N4 for the photocatalytic reduction of 4-nitrophenol to 4-aminophenol in comparison with Cu2O-rGO and C3N4. The Cu2O-rGO-C3N4 photocatalyst was reused for four times without loss in its activity.

  13. Unique structure of iC3b resolved at a resolution of 24 Å by 3D-electron microscopy.

    Science.gov (United States)

    Alcorlo, Martin; Martínez-Barricarte, Ruben; Fernández, Francisco J; Rodríguez-Gallego, César; Round, Adam; Vega, M Cristina; Harris, Claire L; de Cordoba, Santiago Rodríguez; Llorca, Oscar

    2011-08-09

    Activation of C3, deposition of C3b on the target surface, and subsequent amplification by formation of a C3-cleaving enzyme (C3-convertase; C3bBb) triggers the effector functions of complement that result in inflammation and cell lysis. Concurrently, surface-bound C3b is proteolyzed to iC3b by factor I and appropriate cofactors. iC3b then interacts with the complement receptors (CR) of the Ig superfamily, CR2 (CD21), CR3 (CD11b/CD18), and CR4 (CD11c/CD18) on leukocytes, down-modulating inflammation, enhancing B cell-mediated immunity, and targeting pathogens for clearance by phagocytosis. Using EM and small-angle X-ray scattering, we now present a medium-resolution structure of iC3b (24 Å). iC3b displays a unique conformation with structural features distinct from any other C3 fragment. The macroglobulin ring in iC3b is similar to that in C3b, whereas the TED (thioester-containing domain) domain and the remnants of the CUB (complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domain have moved to locations more similar to where they were in native C3. A consequence of this large conformational change is the disruption of the factor B binding site, which renders iC3b unable to assemble a C3-convertase. This structural model also justifies the decreased interaction between iC3b and complement regulators and the recognition of iC3b by the CR of the Ig superfamily, CR2, CR3, and CR4. These data further illustrate the extraordinary conformational versatility of C3 to accommodate a great diversity of functional activities.

  14. Mannan-binding lectin and healing of a radiation-induced chronic ulcer--a case report on mannan-binding lectin replacement therapy

    DEFF Research Database (Denmark)

    Maaløe, Nanna; Bonde, C; Laursen, I

    2011-01-01

    Mannan-binding lectin is an important component of innate immunity, and insufficiency is associated with several clinical disorders. Recently, experimental replacement therapy with plasma-derived mannan-binding lectin has become an option. The current article presents the case of a patient with a...

  15. The galactophilic lectin (PA-IL, gene LecA) from Pseudomonas aeruginosa. Its binding requirements and the localization of lectin receptors in various mouse tissues

    DEFF Research Database (Denmark)

    Kirkeby, Svend; Hansen, Axel K; d'Apice, Anthony

    2006-01-01

    . aeruginosa lectin were compared with the results obtained using an isolectin from the legume shrub Griffonia simplicifolia: the GSI-134 isolectin, which is highly specific for glycans terminating in Ga1 alpha 1-R. In the wild-type mice, lectin histochemistry showed a strong capillary reaction in heart...

  16. P7C3 Neuroprotective Chemicals Block Axonal Degeneration and Preserve Function after Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Terry C. Yin

    2014-09-01

    Full Text Available The P7C3 class of neuroprotective aminopropyl carbazoles has been shown to block neuronal cell death in models of neurodegeneration. We now show that P7C3 molecules additionally preserve axonal integrity after injury, before neuronal cell death occurs, in a rodent model of blast-mediated traumatic brain injury (TBI. This protective quality may be linked to the ability of P7C3 molecules to activate nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in nicotinamide adenine dinucleotide salvage. Initiation of daily treatment with our recently reported lead agent, P7C3-S243, 1 day after blast-mediated TBI blocks axonal degeneration and preserves normal synaptic activity, learning and memory, and motor coordination in mice. We additionally report persistent neurologic deficits and acquisition of an anxiety-like phenotype in untreated animals 8 months after blast exposure. Optimized variants of P7C3 thus offer hope for identifying neuroprotective agents for conditions involving axonal damage, neuronal cell death, or both, such as occurs in TBI.

  17. Atypical Plasmacytic Proliferation in a Case of C3 Glomerulopathy

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    Osama Elfituri MD

    2017-02-01

    Full Text Available An 11-year-old Hispanic female underwent evaluation of asymptomatic proteinuria and hematuria. The patient denied fever, edema, and gross hematuria. Urinalysis showed mild proteinuria, and a urine microscopic examination revealed red blood cells. Screening tests for glomerulonephritis revealed a low C3 and negative ANA, ASO, DNAse-B, and ANCA. Histological examination of a renal biopsy specimen showed glomeruli with endocapillary proliferation, a predominant C3 deposition in the capillary loops by immunofluorescence, and electron dense deposits in the mesangium, paramesangium, and capillary walls by electron microscopy consistent with a diagnosis of C3 glomerulopathy. An interstitial plasmacytosis was also present with focal clustering of plasma cells, which were found to be kappa light chain restricted by in situ hybridization suggestive of a clonal proliferation. One can speculate that these plasma cells may be directly responsible for the renal pathology that was seen.

  18. Acid phosphatase from stored Poa pratensis caryopses and its ability for binding to lectins

    Directory of Open Access Journals (Sweden)

    Irena Lorenc-Kubis

    2014-01-01

    Full Text Available The effect of the storage period of Poa pratensis caryopses on acid phosphatase activity and on the ability of this enzyme to interact with lectins has been studied. It has been shown that after ten years of caryopses storage, the activity of acid phosphatase decreased about 50 per cent, while the content of proteins and carbohydrates did not change. The decrease of enzyme activity during the long period of storage was found only in seeds, but not in chaffs. Acid phosphatase was isolated from caryopses stored one, two, three, five and ten years. The enzyme showed the ability to bind to immoblized as well as to free conA during the whole period of storage, hut did not react with Wheat Germen Agglutinin (WGA. The activation of acid phosphatase by binding to conA decreased with the length of storage period.

  19. A simple two-step purification procedure for the iC3b binding collectin conglutinin

    DEFF Research Database (Denmark)

    Krogh-Meibom, Thomas; Ingvartsen, Klaus Lønne; Tornoe, Ida

    2010-01-01

    Bovine conglutinin is a serum protein involved in innate immunity. It binds calcium dependently to iC3b, a product of the complement component C3 deposited on cell surfaces, immune complexes or artificial surfaces after complement activation. We here present a simple and efficient two-step proced...

  20. Acquired partial lipodystrophy and C3 glomerulopathy: Dysregulation of the complement system as a common mechanism

    Directory of Open Access Journals (Sweden)

    Fernando Corvillo

    2018-05-01

    Full Text Available The activation of the alternative pathway of the complement is involved in the development of several renal diseases, such as atypical haemolytic uraemic syndrome and C3 glomerulopathy. In C3 glomerulopathy, a high percentage of patients have circulating levels of the autoantibody called C3NeF, which causes systemic dysregulation of the complement system. In some cases, the presence of this antibody has been related with abnormalities of adipose tissue, causing acquired partial lipodystrophy (Barraquer–Simons syndrome. Acquired partial lipodystrophy is an extremely rare disorder affecting the distribution of subcutaneous adipose tissue and that mainly onsets during childhood. These patients, in addition to possibly presenting with all the metabolic disorders associated with the adipose tissue defect, present with C3 hypocomplementemia and C3NeF and 25% have developed C3 glomerulopathy. Although it has been known for some time how the dysregulation of the complement system affects the kidneys, it remains unknown how it exactly affects adipose tissue; nevertheless, the relationship is quite clear. In this paper, we describe the connection between the complement system with the biology of the adipose tissue and its pathogenesis reflected from acquired partial lipodystrophy. Resumen: La activación de la vía alternativa del complemento interviene en el desarrollo de varias enfermedades renales, como el síndrome hemolítico urémico atípico o la glomerulopatía C3. En esta última enfermedad un elevado porcentaje de los pacientes presentan niveles circulantes de un autoanticuerpo denominado C3NeF, causante de la desregulación del complemento a nivel sistémico. En ciertos casos, la presencia de este anticuerpo se asocia con alteraciones en el tejido adiposo, causando lipodistrofia parcial adquirida (síndrome de Barraquer-Simons, una enfermedad ultra-rara que afecta a la distribución del tejido adiposo subcutáneo y que comienza principalmente

  1. PgTeL, the lectin found in Punica granatum juice, is an antifungal agent against Candida albicans and Candida krusei.

    Science.gov (United States)

    da Silva, Pollyanna Michelle; de Moura, Maiara Celine; Gomes, Francis Soares; da Silva Trentin, Danielle; Silva de Oliveira, Ana Patrícia; de Mello, Gabriela Souto Vieira; da Rocha Pitta, Maira Galdino; de Melo Rego, Moacyr Jesus Barreto; Coelho, Luana Cassandra Breitenbach Barroso; Macedo, Alexandre José; de Figueiredo, Regina Celia Bressan Queiroz; Paiva, Patrícia Maria Guedes; Napoleão, Thiago Henrique

    2018-03-01

    The pomegranate (Punica granatum) sarcotesta contains a chitin-binding lectin (PgTeL) with antibacterial activity against human pathogenic species. In this work, the structural stability of PgTeL was evaluated by fluorimetric analysis and the lectin was evaluated for cytotoxicity to human peripheral blood mononuclear cells (PBMCs) and antifungal activity against Candida albicans and Candida krusei. PgTeL folding was impaired when lectin was incubated at pH≥6.0. On the other hand, the lectin did not undergo unfolding even when heated at 100°C. PgTeL (1, 10, and 100μg/mL) was not cytotoxic to PBMCs. Antifungal activity was detected for C. albicans (MIC: 25μg/mL; MFC: 50μg/mL) and C. krusei (MIC and MFC of 12.5μg/mL). Treatment of yeast cells with PgTeL resulted in decrease of intracellular ATP content even at sub-inhibitory concentrations (½MIC and ¼MIC) and induced lipid peroxidation. In addition, PgTeL damaged the integrity of fungal cell wall of both species, with more pronounced effects in C. krusei. The lectin showed significant antibiofilm activity on C. albicans at sub-inhibitory concentrations (0.195 and 0.39μg/mL). In conclusion, PgTeL is an anti-Candida agent whose action mechanism involves oxidative stress, energetic collapse, damage to the cell wall and rupture of yeast cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. A novel core 1 O-linked glycan-specific binding lectin from the fruiting body of Hericium erinaceus.

    Science.gov (United States)

    Kim, Seonghun

    2018-02-01

    Mucin-type O-glycans are involved in biological functions on the cell surface as well as the glycoproteins and can also be used as specific carbohydrate biomarkers of many diseases. In this study, I purified a novel core 1 O-linked glycan specific lectin, Hericium erinaceus lecin (HeL), from the fruiting body of the mushroom Hericium erinaceus, which is known as the natural source for a sialic acid-binding lectin. Upon optimization of the purification conditions, a sequence of ion exchange, affinity, ion exchange, and size-exclusion chromatography resulted in the highest yield and best quality of lectin without protease activity. The resulting purified HeL is an apparent hexameric protein with a subunit molecular weight of 15kDa, and a pI of 4.3. In hemagglutination inhibition assay, the purified lectin was only inhibited by glycoproteins containing mucin-type O-glycans and reacted weakly with Galβ(1,3)GalNAc. Glycan array analyses showed that HeL specifically interacts with core 1 O-linked glycans as well as extended O-glycan structures containing sialylation or fucosylation. The glycan binding specificity of HeL is comparable to that of peanut agglutinin for detection of a broader range of extended core 1 O-glycan structures. Taken together, these results provide an efficient and optimized procedure for the purification of HeL from the fruiting body of the mushroom Hericium erinaceus. Moreover, HeL represents a powerful tool for analyzing core 1 and extended core 1 O- glycan structures in diagnosis assays. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Changes in the levels of mannan-binding lectin and ficolins during head-down tilted bed rest.

    Science.gov (United States)

    Kelsen, Jens; Sandahl, Thomas D; Storm, Line; Frings-Meuthen, Petra; Dahlerup, Jens F; Thiel, Steffen

    2014-08-01

    Spaceflight studies and ground-based analogues of microgravity indicate a weakening of human immunity. Mannan-binding lectin (MBL) and H-, L-, and M-ficolin together constitute the lectin pathway and mediate the clearance of pathogens through complement activation. We hypothesized that simulated microgravity may weaken human innate immune functions and studied the impact of 6° head-down tilted bed rest (HDT) for 21 d on MBL and ficolin levels. Within a 6-mo period, seven men underwent two periods of HDT. Blood samples were analyzed for MBL, H-, L-, and M-ficolin, mannose-binding lectin-associated protein of 44 kDa (MAp44), and collectin liver 1 (CL-L1) by time-resolved immunofluorometric assays (TRIFMA). We observed well-defined individual preintervention levels of MBL and ficolins. Remarkably similar intraindividual changes occurred for MBL and MBL levels decreased (mean 282 ng · ml⁻¹) in the recovery phase. Conversely, CL-L1, a protein with MBL-like properties, increased (mean 102 ng · ml⁻¹) during the recovery phase. M-ficolin increased (mean 79 ng · ml⁻¹) within the first 2 d of HDT, followed by a decrease (mean 112 ng · ml⁻¹) during the recovery phase. L-ficolin increased (mean 304 ng · ml⁻¹) during HDT, while H-ficolin was essentially unaffected. MAp44, a down-regulator of the lectin pathway, decreased initially (mean 78 ng · ml⁻¹) in the recovery phase followed by an increase (mean 131 ng · ml⁻¹). Alterations in MBL and ficolin levels were modest and with our current knowledge do not lead to overt immunodeficiency. Pronounced changes occurred when the subjects resumed the upright position. In selected individuals, these changes appear to be a conserved response to HDT.

  4. Glycan microarray analysis of the carbohydrate-recognition specificity of native and recombinant forms of the lectin ArtinM

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2015-12-01

    Full Text Available This article contains data related to the researc.h article entitled “Yeast-derived ArtinM shares structure, carbohydrate recognition, and biological effects with native ArtinM” by Cecílio et al. (2015 [1]. ArtinM, a D-mannose-binding lectin isolated from the seeds of Artocarpus heterophyllus, exerts immunomodulatory and regenerative activities through its Carbohydrate Recognition Domain (CRD (Souza et al., 2013; Mariano et al., 2014 [2,3]. The limited availability of the native lectin (n-ArtinM led us to characterize a recombinant form of the protein, obtained by expression in Saccharomyces cerevisiae (y-ArtinM. We compared the carbohydrate-binding specificities of y-ArtinM and n-ArtinM by analyzing the binding of biotinylated preparations of the two lectin forms using a neoglycolipid (NGL-based glycan microarray. Data showed that y-ArtinM mirrored the specificity exhibited by n-ArtinM.

  5. Cytotoxic Effects of Native and Recombinant Frutalin, a Plant Galactose-Binding Lectin, on HeLa Cervical Cancer Cells

    Directory of Open Access Journals (Sweden)

    Carla Oliveira

    2011-01-01

    Full Text Available Frutalin is the α-D-galactose-binding lectin isolated from breadfruit seeds. Frutalin was obtained from two different sources: native frutalin was purified from its natural origin, and recombinant frutalin was produced and purified from Pichia pastoris. This work aimed to study and compare the effect of native and recombinant frutalin on HeLa cervical cancer cells proliferation and apoptosis. Furthermore, the interaction between frutalin and the HeLa cells was investigated by confocal microscopy. Despite having different carbohydrate-binding affinities, native and recombinant frutalin showed an identical magnitude of cytotoxicity on HeLa cells growth (IC50~100 μg/mL and equally induced cell apoptosis. The interaction studies showed that both lectins were rapidly internalised and targeted to HeLa cell's nucleus. Altogether, these results indicate that frutalin action is not dependent on its sugar-binding properties. This study provides important information about the bioactivity of frutalin and contributes to the understanding of the plant lectins cytotoxic activity.

  6. C-type lectins: their network and roles in pathogen recognition and immunity.

    Science.gov (United States)

    Mayer, Sabine; Raulf, Marie-Kristin; Lepenies, Bernd

    2017-02-01

    C-type lectins (CTLs) represent the most complex family of animal/human lectins that comprises 17 different groups. During evolution, CTLs have developed by diversification to cover a broad range of glycan ligands. However, ligand binding by CTLs is not necessarily restricted to glycans as some CTLs also bind to proteins, lipids, inorganic molecules, or ice crystals. CTLs share a common fold that harbors a Ca 2+ for contact to the sugar and about 18 invariant residues in a phylogenetically conserved pattern. In vertebrates, CTLs have numerous functions, including serum glycoprotein homeostasis, pathogen sensing, and the initiation of immune responses. Myeloid CTLs in innate immunity are mainly expressed by antigen-presenting cells and play a prominent role in the recognition of a variety of pathogens such as fungi, bacteria, viruses, and parasites. However, myeloid CTLs such as the macrophage inducible CTL (Mincle) or Clec-9a may also bind to self-antigens and thus contribute to immune homeostasis. While some CTLs induce pro-inflammatory responses and thereby lead to activation of adaptive immune responses, other CTLs act as inhibitory receptors and dampen cellular functions. Since CTLs are key players in pathogen recognition and innate immunity, targeting CTLs may be a promising strategy for cell-specific delivery of drugs or vaccine antigens and to modulate immune responses.

  7. Winter Aconite (Eranthis hyemalis Lectin as a cytotoxic effector in the lifecycle of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Marie-Therese McConnell

    2015-08-01

    Full Text Available The lectin found in the tubers of the Winter Aconite (Eranthis hyemalis plant is an N-acetyl-D-galactosamine specific Type II Ribosome Inactivating Protein (RIP; Type II RIPs have shown anti-cancer properties, and hence have potential as therapeutic agents. Here we present a modified protocol for the extraction and purification of the E. hyemalis lectin (EHL using affinity chromatography. De novo amino acid sequencing of EHL confirms its classification as a Type II Ribosome Inactivating Protein. The biocidal properties of EHL have been investigated against the nematode Caenorhabditis elegans. Arrested first stage larvae treated with EHL have shown some direct mortality, with surviving larvae subsequently showing a range of phenotypes including food avoidance, reduced fecundity, developmental delay and constitutive dauer larvae formation. Both inappropriate dauer larvae development and failure to locate to bacterial food source are consistent with the disruption of chemosensory function and the ablation of amphid neurons. Further investigation indicates that mutations that disrupt normal amphid formation can block the EHL-induced dauer larvae formation. In combination, these phenotypes indicate that EHL is cytotoxic and suggest a cell specific activity against the amphid neurons of C. elegans.

  8. Tolerability assessment of a lectin fraction from Tepary bean seeds (Phaseolus acutifolius orally administered to rats

    Directory of Open Access Journals (Sweden)

    Roberto Ferriz-Martínez

    2015-01-01

    Full Text Available Our previous studies have shown that a lectin rich fraction (TBLF extracted from Tepary bean seeds differentially inhibits cancer cells proliferation in vitro. Before testing the in vivo anticancer effect, the acute and subchronic toxicological assays in rats were conducted, where an oral dose of 50 mg/body weight kg was determined as the NOAEL. This study evaluated the resistance to digestion and complete blood count (CBC after 24 h of the orally administered 50 mg/kg TBLF. The digestion resistance test showed lectins activity retention after 72 h and the CBC study showed a high level of eosinophils, suggesting an allergic-like response. Tolerability was assayed after 6 weeks of treatment by dosing with an intragastric cannula every third day per week. It was observed a transient reduction in food intake and body weight in the first weeks, resulting in body weight gain reduction of 10% respect to the control group at the end of the study. Additionally, organs weight, histopathological analysis and blood markers for nutritional status and for liver, pancreas and renal function were not affected. Our results suggest that 50 mg/kg TBLF administered by oral route, exhibit no toxicity in rats and it was well tolerated. Further studies will focus on long-term studies.

  9. [The significance of Ulex europaeus agglutinin I lectin binding fibers in various muscular diseases].

    Science.gov (United States)

    Yatabe, K; Hiraguri, M; Sueishi, M; Takeuchi, M; Nonaka, I; Kawai, M

    1998-05-01

    In the present study, we have reported that Ulex europaeus agglutinin I (UEA I) lectin labeled muscle fibers in distal myopathy with rimmed vacuole formation (DMRV). UEA I binding to muscle fibers was also observed in a small number of biopsies with inflammatory myopathy, but not in other diseases, including neurogenic muscular atrophies and muscular dystrophies. In order to elucidate the relationship between this UEA I binding, rimmed vacuole formation and active autophagocytosis, we examined the UEA I binding fibers in other myopathies which frequently showed rimmed vacuoles, including adult onset acid maltase deficiency, oculo-pharyngo-distal type myopathy and oculopharyngeal muscular dystrophy. No UEA I lectin labeling fiber was observed in the diseases examined. We then studied UEA I binding behavior on 70 biopsies of inflammatory myopathy to characterize the clinical features of UEA I binding positive patients. UEA I binding fibers were observed in 3 of 28 patients (11%) with other collagen diseases, 11 of 36 (31%) without these disorders, and 2 of 6 (33%) with inclusion body myositis. There were no common clinical histories, complications or laboratory findings among the UEA I binding positive patients. In conclusion, a common process may exist between the muscle fiber degeneration in DMRV and subgroups of inflammatory myopathy patients, but the basic mechanism remains to be elucidated.

  10. Graphene and g-C3N4 based photocatalysts for NOx removal: A review

    Science.gov (United States)

    Nikokavoura, Aspasia; Trapalis, Christos

    2018-02-01

    NOx liberated into atmosphere from automobile exhausts and fossil fuel combustion, comprise the major air pollutants. They are responsible for serious environmental problems such as acid rain, ozone accumulation, haze and photochemical smog. Besides they contribute to the deterioration of human health by causing decrease of the lung function and respiratory problems. The application of photocatalytic methods in order to mitigate the presence of NOx in the atmosphere is preferable as they are environmentally friendly, mild and low cost. Therefore, in this review, the photocatalytic activity of g-C3N4 and graphene based composites towards NOx removal was discussed. NOx oxidation to non volatile nitrates on the surface of graphene and g-C3N4 based photocatalysts has attracted much interest during the last years due to their structures with unique features such as large specific surface area, thermal and chemical stability and enhanced visible light utilization. The formation of 2D-2D intimate heterojunctions between graphene or g-C3N4 and other components ensures the enhanced charge transfer, lifetime of electron/hole pairs and thus photocatalytic activity. The increased visible light harvesting also contributes to their usefulness as effective photocatalytic materials. In the present work, the advantages of these novel photocatalysts and the differences/similarities between them were exhaustively highlighted. The role of graphene as catalyst promoter, electron reservoir, support and photosensitizer in its photocatalytic composites was emphasized. The effect of g-C3N4 doping and copolymerization with metals/semiconductors on its photocatalytic activity towards NOx oxidation was thoroughly discussed. Besides, the preparation methods, photocatalytic efficiencies, type of irradiation, utilization of appropriate cocatalysts, and reaction mechanisms during the photocatalytic NOx removal by graphene and g-C3N4 composies, were summarized. It was demonstrated that in the vast

  11. Plant lectins: the ties that bind in root symbiosis and plant defense.

    Science.gov (United States)

    De Hoff, Peter L; Brill, Laurence M; Hirsch, Ann M

    2009-07-01

    Lectins are a diverse group of carbohydrate-binding proteins that are found within and associated with organisms from all kingdoms of life. Several different classes of plant lectins serve a diverse array of functions. The most prominent of these include participation in plant defense against predators and pathogens and involvement in symbiotic interactions between host plants and symbiotic microbes, including mycorrhizal fungi and nitrogen-fixing rhizobia. Extensive biological, biochemical, and molecular studies have shed light on the functions of plant lectins, and a plethora of uncharacterized lectin genes are being revealed at the genomic scale, suggesting unexplored and novel diversity in plant lectin structure and function. Integration of the results from these different types of research is beginning to yield a more detailed understanding of the function of lectins in symbiosis, defense, and plant biology in general.

  12. Lectins in fish skin: do they play a role in host-monogenean interactions?

    Science.gov (United States)

    Buchmann, K

    2001-09-01

    Mucus samples from rainbow trout skin with or without infections by Gyrodactylus derjavini were tested for the presence of lectins reacting with mannose, galactose and lactose. The samples inhibited the binding of biotinylated lectins (from Canavalia ensiformis, Artocarpus integrifolia and Erythrina corallodendron, respectively) to microtitre plates with covalently bound carbohydrates (mannopyranoside, galactopyranoside and lactose, respectively). However, the inhibition of C. ensiformis and A. integrifolia lectins was slightly greater when mucus from infected (but recovering) fish was used, suggesting an increase of mannose and galactose binding lectins in fish skin exposed to parasites. As mannose, galactose and lactose are present on the glycocalyx of Gyrodactylus derjavini, it is suggested that lectins could play a dual role in interactions between fish hosts and their monogenean parasites. Thus, recognition between parasite and host and also host responses towards parasite infections could both, at least partly, involve carbohydrate-lectin binding.

  13. Electronic Detection of Lectins Using Carbohydrate Functionalized Nanostructures: Graphene versus Carbon Nanotubes

    Science.gov (United States)

    Chen, Yanan; Vedala, Harindra; Kotchey, Gregg P.; Audfray, Aymeric; Cecioni, Samy; Imberty, Anne; Vidal, Sébastien; Star, Alexander

    2012-01-01

    Here we investigated the interactions between lectins and carbohydrates using field-effect transistor (FET) devices comprised of chemically converted graphene (CCG) and single-walled carbon nanotubes (SWNTs). Pyrene- and porphyrin-based glycoconjugates were functionalized noncovalently on the surface of CCG-FET and SWNT-FET devices, which were then treated with 2 µM of nonspecific and specific lectins. In particular, three different lectins (PA-IL, PA-IIL and ConA) and three carbohydrate epitopes (galactose, fucose and mannose) were tested. The responses of 36 different devices were compared and rationalized using computer-aided models of carbon nanostructure/glycoconjugate interactions. Glycoconjugates surface coverage in addition to one-dimensional structures of SWNTs resulted in optimal lectin detection. Additionally, lectin titration data of SWNT- and CCG-based biosensors were used to calculate lectin dissociation constants (Kd) and compare them to the values obtained from the isothermal titration microcalorimetry (ITC) technique. PMID:22136380

  14. Visualizing the dental biofilm matrix by means of fluorescence lectin-binding analysis

    DEFF Research Database (Denmark)

    Tawakoli, Pune Nina; Neu, Thomas R; Busck, Mette Marie

    2017-01-01

    lectins to visualize and quantify extracellular glycoconjugates in dental biofilms. Lectin binding was screened on pooled supragingival biofilm samples collected from 76 subjects using confocal microscopy. FLBA was then performed with 10 selected lectins on biofilms grown in situ for 48 h in the absence......The extracellular matrix is a poorly studied, yet important component of dental biofilms. Fluorescence lectin-binding analysis (FLBA) is a powerful tool to characterize glycoconjugates in the biofilm matrix. This study aimed to systematically investigate the ability of 75 fluorescently labeled......-biofilms: Aleuria aurantia (AAL), Calystega sepiem (Calsepa), Lycopersicon esculentum (LEA), Morniga-G (MNA-G) and Helix pomatia (HPA). No significant correlation between the binding of specific lectins and bacterial composition was found. Fluorescently labeled lectins enable the visualization of glycoconjugates...

  15. Selective oxidation of alcohols using photoactive VO@g-C3N4.

    Science.gov (United States)

    A photoactive VO@g-C3N4 catalyst has been developed for the selective oxidation of alcohols to the corresponding aldehydes and ketones. The visible light mediated activity of the catalyst could be attributed to photoactive graphitic carbon nitrides surface.

  16. Novel indole-based inhibitors of IMPDH: introduction of hydrogen bond acceptors at indole C-3.

    Science.gov (United States)

    Watterson, Scott H; Dhar, T G Murali; Ballentine, Shelley K; Shen, Zhongqi; Barrish, Joel C; Cheney, Daniel; Fleener, Catherine A; Rouleau, Katherine A; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2003-04-07

    The development of a series of novel indole-based inhibitors of 5'-inosine monophosphate dehydrogenase (IMPDH) is described. Various hydrogen bond acceptors at C-3 of the indole were explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are outlined.

  17. Immunoglobulins and C3 in the P. brasiliensis granuloma

    Directory of Open Access Journals (Sweden)

    Lilian M. V. Biagioni

    1987-04-01

    Full Text Available The experimental model of paracoccidioidomycosis induced in mice by the intravenous injection of yeast-forms of P. brasiliensis (Bt2 strain; 1 x 10(6 viable fungi/animal was used to evaluate sequentially 2, 4, 8, 16 and 20 weeks after inoculation: 1. The presence of immunoglobulins and C3 in the pulmonary granuloma-ta, by direct immunofluorescence; 2. The humoral (immunodiffusion test and the cellular (footpad sweeling test immune response; 3. The histopathology of lesions. The cell-immune response was positive since week 2, showing a transitory depression at week 16. Specific antibodies were first detected at week 4 and peaked at week 16. At histology, epithelioid granulomas with numerous fungi and polymorphonuclear agreggates were seen. The lungs showed progressive involvement up to week 16, with little decrease at week 20. From week 2 on, there were deposits of IgG and C3 around fungal walls within the granulomas and IgG stained cells among the mononuclear cell peripheral halo. Interstitital immunoglobulins and C3 deposits in the granulomas were not letected. IgG and C3 seen to play an early an important role in. the host defenses against P. brasiliensis by possibly cooperating in the killing of parasites and blocking the antigenic diffusion.

  18. Screening for C3 deficiency in newborns using microarrays.

    Directory of Open Access Journals (Sweden)

    Magdalena Janzi

    Full Text Available BACKGROUND: Dried blood spot samples (DBSS from newborns are widely used in neonatal screening for selected metabolic diseases and diagnostic possibilities for additional disorders are continuously being evaluated. Primary immunodeficiency disorders comprise a group of more than one hundred diseases, several of which are fatal early in life. Yet, a majority of the patients are not diagnosed due to lack of high-throughput screening methods. METHODOLOGY/PRINCIPAL FINDINGS: We have previously developed a system using reverse phase protein microarrays for analysis of IgA levels in serum samples. In this study, we extended the applicability of the method to include determination of complement component C3 levels in eluates from DBSS collected at birth. Normal levels of C3 were readily detected in 269 DBSS from healthy newborns, while no C3 was detected in sera and DBSS from C3 deficient patients. CONCLUSIONS/SIGNIFICANCE: The findings suggest that patients with deficiencies of specific serum proteins can be identified by analysis of DBSS using reverse phase protein microarrays.

  19. 26 CFR 301.6224(c)-3 - Consistent settlements.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Consistent settlements. 301.6224(c)-3 Section... settlements. (a) In general. If the Internal Revenue Service enters into a settlement agreement with any..., settlement terms consistent with those contained in the settlement agreement entered into. (b) Requirements...

  20. C3 Epimerization of Glucose, via Regioselective Oxidation and Reduction

    NARCIS (Netherlands)

    Jumde, Varsha R.; Eisink, Niek N. H. M.; Witte, Martin D.; Minnaard, Adriaan J.

    2016-01-01

    Palladium-catalyzed oxidation can single out the secondary hydroxyl group at C3 in glucose, circumventing the more readily accessible hydroxyl at C6 and the more reactive anomeric hydroxyl. Oxidation followed by reduction results in either allose or allitol, each a rare sugar that is important in

  1. Evaluation of EGM 2008 and EIGEN-6C3stat \

    Czech Academy of Sciences Publication Activity Database

    Kostelecký, J.; Klokočník, Jaroslav; Bezděk, Aleš

    -, č. 5 (2015), s. 3-12 ISSN 1810-8555 R&D Projects: GA ČR GA13-36843S Grant - others:GA MŠk(CZ)(CZ) CZ.1.05/1.1.00/02.0090 Institutional support: RVO:67985815 Keywords : gravity field evaluation * EGM 2008 * EIGEN-6C3stat Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  2. Electronic structure and mechanical properties of Cr7C3

    International Nuclear Information System (INIS)

    Music, D.; Kreissig, U.; Mertens, R.; Schneider, J.M.

    2004-01-01

    We have studied the Cr 7 C 3 phase by means of ab initio calculations and found covalent-ionic Cr-C-Cr chains in a metallic matrix. Furthermore, the structure of thin films, synthesized by RF magnetron sputtering, is shown to be in good agreement with our theoretical prediction

  3. Regioselective synthesis of C3 alkylated and arylated benzothiophenes

    Science.gov (United States)

    Shrives, Harry J.; Fernández-Salas, José A.; Hedtke, Christin; Pulis, Alexander P.; Procter, David J.

    2017-03-01

    Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon-hydrogen bonds, found in all organic molecules, can be directly converted into carbon-carbon bonds. In the case of elaborating benzothiophenes, functionalization of carbon-hydrogen bonds at carbon-number 3 (C3) is markedly more demanding than at C2 due to issues of regioselectivity (C3 versus C2), and the requirement of high temperatures, precious metals and the installation of superfluous directing groups. Herein, we demonstrate that synthetically unexplored but readily accessible benzothiophene S-oxides serve as novel precursors for C3-functionalized benzothiophenes. Employing an interrupted Pummerer reaction to capture and then deliver phenol and silane coupling partners, we have discovered a directing group-free method that delivers C3-arylated and -alkylated benzothiophenes with complete regioselectivity, under metal-free and mild conditions.

  4. Unconventionally prepared TiO2/g-C3N4 photocatalysts for photocatalytic decomposition of nitrous oxide

    Science.gov (United States)

    Troppová, Ivana; Šihor, Marcel; Reli, Martin; Ritz, Michal; Praus, Petr; Kočí, Kamila

    2018-02-01

    The TiO2/g-C3N4 nanocomposites with the various TiO2:g-C3N4 weight ratios from 1:1 to 1:3 were prepared unconventionally by pressurized hot water processing in a flow regime. The parent TiO2 and g-C3N4 was prepared by thermal hydrolysis and thermal annealing, respectively. The nanocomposites as well as parent TiO2 and g-C3N4 were characterized using several complementary characterization methods and investigated in the photocatalytic decomposition of N2O under UVA (λ = 365 nm) irradiation. All the prepared TiO2/g-C3N4 nanocomposites showed higher photocatalytic activity in comparison with the pure g-C3N4 and chiefly pure TiO2. The photocatalytic activity of TiO2/g-C3N4 nanocomposites was decreasing in the following sequence: TiO2/g-C3N4 (1:3) > TiO2/g-C3N4 (1:2) > TiO2/g-C3N4 (1:1). In comparison with the parent TiO2 or g-C3N4, the TiO2/g-C3N4 nanocomposites' photocatalytic capability was significantly enhanced by coupling TiO2 with g-C3N4. The generation of TiO2/g-C3N4 Z-scheme photocatalyst mainly benefited from the effective separation of photoinduced electron-hole pairs and the extended optical absorption range. The TiO2/g-C3N4 (1:3) nanocomposite showed the best photocatalytic behavior in a consequence of the optimal weight ratio of TiO2:g-C3N4 and the lowest band gap energy from all nanocomposites. The N2O conversion in its presence was 70.6% after 20 h of UVA irradiation.

  5. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2017-01-01

    The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition...... the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system....... Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part...

  6. Glycoproteins of axonal transport: affinity chromatography on fucose-specific lectins

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, S.; Ohlson, C.; Karlsson, J.O.

    1982-03-01

    Rapidly transported fucose-labeled glycoproteins from axons of rabbit retinal ganglion cells were solubilized with nonionic detergents. The solubilized components were subjected to affinity chromatography on three different fucose-specific lectins. A recently characterized fucose-specific lectin from Aleuria aurantia bound reversibly approximately 60% of the applied protein-bound radioactivity. The lectins from Lotus tetragonolobus and Ulex europaeus bound are very small proportions of the labeled rapidly transported glycoproteins.

  7. Sugar residues content and distribution in atrophic and hyperplastic postmenopausal human endometrium: lectin histochemistry

    OpenAIRE

    Gheri, G.; Gheri Bryk, S.; Taddei, G.; Moncini, D.; Noci, I.

    1996-01-01

    A lectin histochemical study was performed to investigate the glycoconjugate saccharidic moieties of the human postmenopausal endometrium (14 atrophic and 15 hyperplastic). For this purpose a battery of seven horseradish peroxidase-conjugated lectins (PNA, SBA, DBA, WGA, ConA, LTA and UEA I) was used. No differences in lectin binding between atrophic and hyperplastic endometria were observed. This investigation allowed us to provide a basic picture of the oligo...

  8. C-type lectins in immunity: recent developments

    Science.gov (United States)

    Dambuza, Ivy M; Brown, Gordon D

    2015-01-01

    C-type lectin receptors (CLRs) comprise a large superfamily of proteins, which recognise a diverse range of ligands, and are defined by the presence of at least one C-type lectin-like domain (CTLD). Of particular interest are the single extracellular CTLD-containing receptors of the ‘Dectin-1’ and ‘Dectin-2’ clusters, which associate with signalling adaptors or possess integral intracellular signalling domains. These CLRs have traditionally been associated with the recognition of fungi, but recent discoveries have revealed diverse and unexpected functions. In this review, we describe their newly identified roles in anti-microbial host defence, homeostasis, autoimmunity, allergy and their functions in the recognition and response to dead and cancerous cells. PMID:25553393

  9. [Studies on the location of eight lectins in breast carcinoma].

    Science.gov (United States)

    Zheng, Z; Ji, Z M

    1990-12-01

    100 cases of breast carcinoma were studied with lectin affinitive histochemistry technology. The result showed that Ricinus comunis agglutinin (RCA1) was located in almost all intraductal carcinomas but one, while the positive rates in the other types were obviously low (P less than 0.05). The positive rate of Ulex europaeus agglutinin-I (UEA1) in well-differentiated types was higher than that in poorly-differentiated ones (P less than 0.05). The location of Peanut agglutinin (PNA), Bandeiraea Simplicifolia (BSL) and UEA1 in breast carcinomas exhibited some regularity and it might be useful in understanding the differentiation of breast carcinomas. No relationship between changes of the eight lectins and metastases in axillary lymph nodes was observed, but the authors considered that PNA-affinitive histochemistry was beneficial to the detection of micrometastases in lymph nodes.

  10. The Crystal Structure of Cobra Venom Factor, a Cofactor for C3- and C5-Convertase CVFBb

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Vengadesan; Ponnuraj, Karthe; Xu, Yuanyuan; Macon, Kevin; Volanakis, John E.; Narayana, Sthanam V.L.; (Madras); (UAB)

    2009-05-26

    Cobra venom factor (CVF) is a functional analog of human complement component C3b, the active fragment of C3. Similar to C3b, in human and mammalian serum, CVF binds factor B, which is then cleaved by factor D, giving rise to the CVFBb complex that targets the same scissile bond in C3 as the authentic complement convertases C4bC2a and C3bBb. Unlike the latter, CVFBb is a stable complex and an efficient C5 convertase. We solved the crystal structure of CVF, isolated from Naja naja kouthia venom, at 2.6 {angstrom} resolution. The CVF crystal structure, an intermediate between C3b and C3c, lacks the TED domain and has the CUB domain in an identical position to that seen in C3b. The similarly positioned CUB and slightly displaced C345c domains of CVF could play a vital role in the formation of C3 convertases by providing important primary binding sites for factor B.

  11. An AgI@g-C3N4 hybrid core@shell structure: Stable and enhanced photocatalytic degradation

    Science.gov (United States)

    Liu, Li; Qi, Yuehong; Yang, Jinyi; Cui, Wenquan; Li, Xingang; Zhang, Zisheng

    2015-12-01

    A novel visible-light-active material AgI@g-C3N4 was prepared by ultrasonication/chemisorption method. The core@shell structure AgI@g-C3N4 catalyst showed high efficiency for the degradation of MB under visible light irradiation (λ > 420 nm). Nearly 96.5% of MB was degraded after 120 min of irradiation in the presence of the AgI@g-C3N4 photocatalyst. Superior stability was also observed in the cyclic runs indicating that the as prepared hybrid composite is highly desirable for the remediation of organic contaminated wastewaters. The improved photocatalytic performance is due to synergistic effects at the interface of AgI and g-C3N4 which can effectively accelerate the charge separation and reinforce the photostability of hybrid composite. The possible mechanism for the photocatalytic activity of AgI@g-C3N4 was tentatively proposed.

  12. The Preparation of Cu-g-C3N4/AC Catalyst for Acetylene Hydrochlorination

    Directory of Open Access Journals (Sweden)

    Wenli Zhao

    2016-12-01

    Full Text Available A novel catalyst based on g-C3N4/activated carbon was prepared by adding CuCl2. The catalytic performance of the as-prepared catalyst was investigated in the acetylene hydrochlorination reaction. X-ray photoelectron spectroscopy, temperature programmed desorption, low temperature N2 adsorption/desorption (Brunauer–Emmett–Teller, and thermal gravity analysis showed that Cu-g-C3N4/AC significantly enhanced the catalytic performance of the original catalyst by increasing the relative pyrrolic N content. Cu-g-C3N4/AC also affected the adsorption of hydrogen chloride and acetylene, as well as inhibited the coke deposition during acetylene hydrochlorination.

  13. Cytotoxicity and Glycan-Binding Properties of an 18 kDa Lectin Isolated from the Marine Sponge Halichondria okadai

    Directory of Open Access Journals (Sweden)

    Yasuhiro Ozeki

    2012-04-01

    Full Text Available A divalent cation-independent lectin—HOL-18, with cytotoxic activity against leukemia cells, was purified from a demosponge, Halichondria okadai. HOL-18 is a 72 kDa tetrameric lectin that consists of four non-covalently bonded 18 kDa subunits. Hemagglutination activity of the lectin was strongly inhibited by chitotriose (GlcNAcβ1-4GlcNAcβ1-4GlcNAc, fetuin and mucins from porcine stomach and bovine submaxillary gland. Lectin activity was stable at pH 4–12 and temperatures lower than 60 °C. Frontal affinity chromatography with 16 types of pyridylaminated oligosaccharides indicated that the lectin had an affinity for N-linked complex-type and sphingolipid-type oligosaccharides with N-acetylated hexosamines and neuramic acid at the non-reducing termini. The lectin killed Jurkat leukemia T cells and K562 erythroleukemia cells in a dose- and carbohydrate-dependent manner.

  14. Growth and N2-fixation of Dhaincha C-3/Sorghum C-4 and Dhaincha C-3/Sunflower C-3 intercropping systems using the 15N and 13C natural abundance method technique

    International Nuclear Information System (INIS)

    Kurdali, F.

    2007-06-01

    A field experiment on dhaincha C 3 (Sesbania aculeata Pers), sunflower C 3 (Helianthus annuus L.) and sorghum C 4 (Sorghum bicolor L.) plants grown in monocropping and intercropping systems was conducted to evaluate seed yield, dry matter production, total N yield, land equivalent ratio (LER), intraspecific competition for soil N uptake, water use efficiency (WUE) and N 2 -fixation using the 15 N natural abundance technique (δ 15 N ). Moreover, carbon isotope discrimination (Δ13 C ) was determined to assess factors responsible for crop performance variability in the different cropping systems. Intercropping of sesbania/sorghum showed greater efficiency over monocropping in producing dry matter, during the entire growth period, as indicated by the LERs (>1); whereas, the efficiency of producing dry matter in the sesbania /sunflower intercropping was similar to that in the monocropping system (LER=1). Moreover, sorghum plants (C 4 ) was more competitive than sesbania (C 3 ) for soil N uptake; whereas, sesbania seemed to be more competitive than its associated sunflower (C 3 ). N uptake in the mixed stand of sesbania/sorghum was improved due to the increase in soil N uptake by the component sorghum and the higher root nodule activity of component sesbania without affecting the amount of N 2 fixed. In both cropping systems, sesbania plants fixed almost the same amount of N 2 (an average of 105 kg N/ha) although the number of rows in the mixed stand was 2/3 of that in the pure stand. This gives an advantage of the intercropping over sole cropping system with regards to N 2 -fixation. 13 C discrimination in plant materials was found to be affected by plant species and the cropping system. Factors affected Δ13 C in plants grown in the mixed stand relative to solely grown crops are discussed.(author)

  15. Nkrp1 Family, from Lectins to Protein Interacting Molecules

    Czech Academy of Sciences Publication Activity Database

    Rozbeský, Daniel; Ivanova, Ljubina; Hernychová, Lucie; Grobárová, Valeria; Novák, Petr; Černý, J.

    2015-01-01

    Roč. 20, č. 2 (2015), s. 3463-3478 ISSN 1420-3049 R&D Projects: GA MŠk(CZ) EE2.3.20.0055; GA MŠk(CZ) EE2.3.30.0003; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : NATURAL-KILLER-CELL * C-TYPE LECTIN * CARBOHYDRATE -RECOGNITION DOMAIN Subject RIV: CC - Organic Chemistry Impact factor: 2.465, year: 2015

  16. Toxicity and Binding Profile of Lectins from the Genus Canavalia on Brine Shrimp

    Directory of Open Access Journals (Sweden)

    Francisco Vassiliepe Sousa Arruda

    2013-01-01

    Full Text Available Lectins are sugar-binding proteins widely distributed in nature with many biological functions. Although many lectins have a remarkable biotechnological potential, some of them can be cytotoxic. Thus, the aim of this study was to assess the toxicity of five lectins, purified from seeds of different species of Canavalia genus. In order to determine the toxicity, assays with Artemia nauplii were performed. In addition, a fluorescence assay was carried out to evaluate the binding of lectins to Artemia nauplii. In order to verify the relationship between the structure of lectins and their cytotoxic effect, structural analysis was carried out to evaluate the volume of the carbohydrate recognition domain (CRD of each lectin. The results showed that all lectins exhibited different toxicities and bound to a similar area in the digestive tract of Artemia nauplii. Concerning the structural analysis, differences in spatial arrangement and volume of CRD may explain the variation of the toxicity exhibited by each lectin. To this date, this is the first study that establishes a link between toxicity and structure of CRD from Diocleinae lectins.

  17. Preparation of WO3/g-C3N4 composites and their application in oxidative desulfurization

    Science.gov (United States)

    Zhao, Rongxiang; Li, Xiuping; Su, Jianxun; Gao, Xiaohan

    2017-01-01

    WO3/graphitic carbon nitride (g-C3N4) composites were successfully synthesized through direct calcining of a mixture of WO3 and g-C3N4 at 400 °C for 2 h. The WO3 was prepared by calcination of phosphotungstic acid at 550 °C for 4 h, and the g-C3N4 was obtained by calcination of melamine at 520 °C for 4 h. The WO3/g-C3N4 composites were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunner-Emmett-Teller analysis (BET). The WO3/g-C3N4 composites exhibited stronger XRD peaks of WO3 and g-C3N4 than the WO3 and pure g-C3N4. In addition, two WO3 peaks at 25.7° and 26.6° emerged for the 36% -WO3/g-C3N4 composite. This finding indicated that WO3 was highly dispersed on the surface of the g-C3N4 nanosheets and interacted with the nanosheets, which resulted in the appearance of (012) and (022) planes of WO3. The WO3/g-C3N4 composite also exhibited a larger specific surface area and higher degree of crystallization than WO3 or pure g-C3N4, which resulted in high catalytic activity of the catalyst. Desulfurization experiments demonstrated that the desulfurization rate of dibenzothiophene (DBT) in model oil reached 91.2% under optimal conditions. Moreover, the activity of the catalyst was not significantly decreased after five recycles.

  18. Development of gastrointestinal surface. VIII. Lectin identification of carbohydrate differences

    International Nuclear Information System (INIS)

    Pang, K.Y.; Bresson, J.L.; Walker, W.A.

    1987-01-01

    Binding of microvillus membranes (MVM) from newborn and adult rats by concanavalin A (Con A), Ulex europaeus (UEA I), Dolichos bifluorus (DBA), and Triticum vulgaris (WGA) was examined to determine the availability of carbohydrate-containing sites for these lectins on the intestinal surface during development. Consistent patterns of differences in the reaction of MVM with these lectins were found. Con A and UEA had much higher reactivities to MVM of adult than newborn rats. 125 I-labeled-UEA gel overlay experiments revealed the abundance of UEA-binding sites in MVM of adult rat in contrast to the two binding sites in MVM of a newborn rat. DBA bound only to MVM of the adults, and very few binding sites were found in immature MVM. In contrast to these lectins, WGA binding was much higher in MVM of the newborns and decreased with maturation. Additional experiments on the age dependence of UEA and DBA reactivities revealed that the most striking changes occur in animals from 2 to 2 wk of age. In MVM from 2-wk-old rats, there were only 13.9% and < 0.2% of the adult binding capacities for UEA and DBA, respectively. By the time the animals were 4 wk old, the binding capacity for UEA had attained close to the level of the adults, whereas for DBA it reached 71.3% of the adult value. These results provide definite evidence of changes in the intestinal surface during perinatal development

  19. Development of gastrointestinal surface. VIII. Lectin identification of carbohydrate differences

    Energy Technology Data Exchange (ETDEWEB)

    Pang, K.Y.; Bresson, J.L.; Walker, W.A.

    1987-05-01

    Binding of microvillus membranes (MVM) from newborn and adult rats by concanavalin A (Con A), Ulex europaeus (UEA I), Dolichos bifluorus (DBA), and Triticum vulgaris (WGA) was examined to determine the availability of carbohydrate-containing sites for these lectins on the intestinal surface during development. Consistent patterns of differences in the reaction of MVM with these lectins were found. Con A and UEA had much higher reactivities to MVM of adult than newborn rats. /sup 125/I-labeled-UEA gel overlay experiments revealed the abundance of UEA-binding sites in MVM of adult rat in contrast to the two binding sites in MVM of a newborn rat. DBA bound only to MVM of the adults, and very few binding sites were found in immature MVM. In contrast to these lectins, WGA binding was much higher in MVM of the newborns and decreased with maturation. Additional experiments on the age dependence of UEA and DBA reactivities revealed that the most striking changes occur in animals from 2 to 2 wk of age. In MVM from 2-wk-old rats, there were only 13.9% and < 0.2% of the adult binding capacities for UEA and DBA, respectively. By the time the animals were 4 wk old, the binding capacity for UEA had attained close to the level of the adults, whereas for DBA it reached 71.3% of the adult value. These results provide definite evidence of changes in the intestinal surface during perinatal development.

  20. Histochemistry of lectin-binding sites in Halicryptus spinulosus (Priapulida).

    Science.gov (United States)

    Busch, A; Schumacher, U; Storch, V

    2001-02-01

    Priapulida represent one of the phylogenetically oldest multicellular animal groups. In multicellular animals (Metazoa) cell-to-cell and cell-to-matrix interactions are often mediated by carbohydrate residues of glycoconjugates. To analyze the carbohydrate composition of a phylogenetically old species, lectin histochemistry was employed on 5 specimens of the priapulid Halicryptus spinulosus. Many lectins bound to the chitin-containing cuticle, including those specific for carbohydrates other than N-acetylglucosamine, the principle building block of chitin. The connective tissue of the animals contained both N-acetylglucosamine and N-acetylgalactosamine. Mannose residues were widely distributed with the exception of the cuticle, but complex type carbohydrates were not present in the entire animal. Sialic acid residues were only detected in the cuticle and brush border of the intestinal epithelium, while fucose was limited to the cuticle. Thus, the lectin-binding pattern indicated that sugars typical for the linking region of both N- and O-glycoproteins in mammals are also present in H. spinulosus. Carbohydrate residues that are typical for the complex type of N-linked glycans in vertebrates are not present as are carbohydrate residues typical for the termination of O-linked carbohydrate chains. Hence, a truncated form of both N- and O-linked glycosylation is present in H. spinulosus indicating that more complex patterns of glycosylation developed later during evolution.

  1. Labeling of lectin receptors during the cell cycle.

    Science.gov (United States)

    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.

  2. A chitin-binding lectin from Moringa oleifera seeds (WSMoL) impairs the digestive physiology of the Mediterranean flour larvae, Anagasta kuehniella.

    Science.gov (United States)

    de Oliveira, Caio Fernando Ramalho; de Moura, Maiara Celine; Napoleão, Thiago Henrique; Paiva, Patrícia Maria Guedes; Coelho, Luana Cassandra Breitenbach Barroso; Macedo, Maria Lígia Rodrigues

    2017-10-01

    Biotechnological techniques allow the investigation of alternatives to outdated chemical insecticides for crop protection; some investigations have focused on the identification of molecules tailored from nature for this purpose. We, herein, describe the negative effects of water-soluble lectin from Moringa oleifera seeds (WSMoL) on Anagasta kuehniella development. The chitin-binding lectin, WSMoL, impaired the larval weight gain by 50% and affected the activity of the pest's major digestive enzymes. The commitment of the digestive process became evident after controlled digestion studies, where the capacity of protein digestion was compromised by >90%. Upon acute exposure, the lectin was not resistant to digestion; however, chronic ingestion of WSMoL was able to reverse this feature. Thus, we show that resistance to digestion may not be a prerequisite for a lectin's ability to exert negative effects on larval physiology. The mechanism of action of WSMoL involves binding to chitin with possible disruption to the peritrophic membrane, causing disorder between the endo- and ectoperitrophic spaces. Additionally, results suggest that WSMoL may trigger apoptosis in gut cells, leading to the lower enzymatic activity observed in WSMoL-fed larvae. Although assays employing an artificial diet did not demonstrate effects of WSMoL on A. kuehniella mortality, this lectin may hold potential for exerting insecticide effects on other pest insects, as well for use in other experimental approaches, such as WSMoL-expressing plants. Moreover, the use of WSMoL with other biotechnological tools, such as 'pyramid' crops, may represent a strategy for delaying the evolution of pest resistance to transgenic crops, since its multiple site targets could act in synergism with other insecticide compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Preparation of WO3/g-C3N4 composites and their application in oxidative desulfurization

    International Nuclear Information System (INIS)

    Zhao, Rongxiang; Li, Xiuping; Su, Jianxun; Gao, Xiaohan

    2017-01-01

    Highlights: • The WO 3 /g-C 3 N 4 was successfully synthesized through simple calcination. • The process is simple and the cost raw materials is cheap. • The WO 3 /g-C 3 N 4 firstly applied to ODS. • The desulpurization rate of WO 3 /g-C 3 N 4 may attach to 91.2%. • Five recycles of WO 3 /g-C 3 N 4 still attach to 89.5% due to heterogeneous catalysis. - Abstract: WO 3 /graphitic carbon nitride (g-C 3 N 4 ) composites were successfully synthesized through direct calcining of a mixture of WO 3 and g-C 3 N 4 at 400 °C for 2 h. The WO 3 was prepared by calcination of phosphotungstic acid at 550 °C for 4 h, and the g-C 3 N 4 was obtained by calcination of melamine at 520 °C for 4 h. The WO 3 /g-C 3 N 4 composites were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunner−Emmett−Teller analysis (BET). The WO 3 /g-C 3 N 4 composites exhibited stronger XRD peaks of WO 3 and g-C 3 N 4 than the WO 3 and pure g-C 3 N 4 . In addition, two WO 3 peaks at 25.7° and 26.6° emerged for the 36% −WO 3 /g-C 3 N 4 composite. This finding indicated that WO 3 was highly dispersed on the surface of the g-C 3 N 4 nanosheets and interacted with the nanosheets, which resulted in the appearance of (012) and (022) planes of WO 3 . The WO 3 /g-C 3 N 4 composite also exhibited a larger specific surface area and higher degree of crystallization than WO 3 or pure g-C 3 N 4 , which resulted in high catalytic activity of the catalyst. Desulfurization experiments demonstrated that the desulfurization rate of dibenzothiophene (DBT) in model oil reached 91.2% under optimal conditions. Moreover, the activity of the catalyst was not significantly decreased after five recycles.

  4. Generation of Anaphylatoxins by Human β-Tryptase from C3, C4, and C51

    Science.gov (United States)

    Fukuoka, Yoshihiro; Xia, Han-Zhang; Sanchez-Muñoz, Laura B.; Dellinger, Anthony L.; Escribano, Luis; Schwartz, Lawrence B.

    2009-01-01

    Both mast cells and complement participate in innate and acquired immunity. The current study examines whether β-tryptase, the major protease of human mast cells, can directly generate bioactive complement anaphylatoxins. Important variables included pH, monomeric vs tetrameric forms of β-tryptase, and the β-tryptase-activating polyanion. The B12 mAb was used to stabilize β-tryptase in its monomeric form. C3a and C4a were best generated from C3 and C4, respectively, by monomeric β-tryptase in the presence of low molecular weight dextran sulfate or heparin at acidic pH. High molecular weight polyanions increased degradation of these anaphylatoxins. C5a was optimally generated from C5 at acidic pH by β-tryptase monomers in the presence of high molecular weight dextran sulfate and heparin polyanions, but also was produced by β-tryptase tetramers under these conditions. Mass spectrometry verified that the molecular mass of each anaphylatoxin was correct. Both β-tryptase-generated C5a and