Lectins: cell-agglutinating and sugar-specific proteins

Lectins as a tool for detecting neural stem/progenitor cells in the adult mouse brain

Glycoconjugates are biopolymers that are broadly distributed in the central nervous system, including the cell surface of neural stem cells or neural precursor cells (NSCs/NPCs). Glycoconjugates can be recognized by carbohydrate-binding proteins, lectins. Two lectins, Phaseolus vulgaris lectin agglutinin E-form (PHA-E4) and wheat germ agglutinin (WGA) have been reported to be useful in isolating NSCs/NPCs by fluorescence-activated cell sorting (FACS) or immunopanning methods. In this study, we analyzed the lectin-binding properties of NSCs/NPCs in two neurogenic regions of the adult mouse brain to determine whether PHA-E4 and WGA exhibit specific binding patterns on sections and whether there are other lectins presenting the binding pattern similar to those of PHA-E4 and WGA in lectin histochemistry. Among nine types of lectins, peanut agglutinin was localized to the white matter and four lectins bound to cells within the subventricular zone (SVZ) of the lateral ventricle. Lectin histochemistry combined with immunohistochemistry demonstrated that one lectin, Ricinus communis agglutinin, specifically detected type A neuronal precursors and that the remaining three lectins, Agaricus bisporus agglutinin (ABA), PHA-E4, and WGA, recognized type B NSCs and type C transient amplifying cells in the SVZ. These three lectins also recognized type 1 quiescent neural progenitors and type 2a amplifying neural progenitors in the subgranular layer of the dentate gyrus. Lectin histochemistry of the neurosphere culture also yielded similar results. These observations suggest that, in addition to PHA-E4 and WGA, ABA lectin may also be applicable in FACS or immunopanning for the isolation of NSCs/NPCs.

Mushroom lectins: current status and future perspectives

Lectins are nonimmune proteins or glycoproteins that bind specifically to cell surface carbohydrates, culminating in cell agglutination. These are known to play key roles in host defense system and also in metastasis. Many new sources have been explored for the occurrence of lectins during the last few years. Numerous novel lectins with unique specificities and exploitable properties have been discovered. Mushrooms have attracted a number of researchers in food and pharmaceuticals. Many species have long been used in traditional Chinese medicines or functional foods in Japan and other Asian countries. A number of bioactive constituents have been isolated from mushrooms including polysaccharides, polysaccharopeptides, polysaccharide-protein complexes, proteases, ribonucleases, ribosome inactivating proteins, antifungal proteins, immunomodulatory proteins, enzymes, lectins, etc. Mushroom lectins are endowed with mitogenic, antiproliferative, antitumor, antiviral, and immune stimulating potential. In this review, an attempt has been made to collate the information on mushroom lectins, their blood group and sugar specificities, with an emphasis on their biomedical potential and future perspectives.

Lectins: a possible basis for specificity in the Rhizobium--legume root nodule symbiosis

Soybean lectin labeled with fluorescein isothiocyanate combined specifically with all but 3 of 25 strains of the soybean-nodulating bacterium Rhizobium japonicum. The lectin did not bind to any of 23 other strains representative of rhizobia that do not nodulate soybeans. The evidence suggests that an interaction between legume lectins and Rhizobium cells may account for the specificity expressed between rhizobia and host plant in the initiation of the nitrogen-fixing symbiosis.

Automated platform for fractionation of human plasma glycoproteome in clinical proteomics

This publication describes the development of an automated platform for the study of the plasma glycoproteome. The method consists of targeted depletion in-line with glycoprotein fractionation. A key element of this platform is the enabling of high throughput sample processing in a manner that minimizes analytical bias in a clinical sample set. The system, named High Performance Multi-Lectin Affinity Chromatography (HP-MLAC), is composed of a serial configuration of depletion columns containing anti-albumin antibody and protein A with in-line multilectin affinity chromatography (M-LAC) which consists of three mixtures of lectins concanavalin A (ConA), jacalin (JAC), and wheat germ agglutinin (WGA). We have demonstrated that this platform gives high recoveries for the fractionation of the plasma proteome (> or = 95%) and excellent stability (over 200 runs). In addition, glycoproteomes isolated using the HP-MLAC platform were shown to be highly reproducible and glycan specific as demonstrated by rechromatography of selected fractions and proteomic analysis of the unbound (glycoproteome 1) and bound (glycoproteome 2) fractions.

On-chip dielectrophoretic coassembly of live cells and particles into responsive biomaterials

We report how live cells and functionalized colloidal particles can be coassembled into a variety of freely suspended bioactive structures using dielectrophoresis on a chip. Alternating electric fields were applied to dilute suspensions of yeast (S. cerevisiae) and NIH/3T3 mouse fibroblast cells to yield 1D chains and 2D arrays. The effects of voltage, frequency, pH, electrolyte concentration, cell concentration, and particle size on the assembly process were investigated in detail. Numerical simulations of the field intensity and energy allow the capture of the dynamics of cell-cell and cell-particle assembly. The simulation results illustrate that the electric field draws the functionalized synthetic particles between the cells and enables the formation of permanent chains and monolayer membranes composed of alternating cells and particles. The cell structures were bound into permanent structures by different types of functionalized synthetic particles and ligands that attached to the cells through biospecific or electrostatic interactions. The technique allowed the fabrication of magnetically responsive biomaterials that could be manipulated and transported into and out of the microchambers where they were formed.

Taenia saginata metacestode antigenic fractions without affinity to concanavalin A are an important source of specific antigens for the diagnosis of human neurocysticercosis

Taenia saginata metacestode antigens have been constituted a useful alternative antigen for neurocysticercosis (NC) serodiagnosis, particularly due to an increasing difficulty to obtain Taenia solium homologous antigen. Cross-reactivity with Echinococcus granulosus infection occurs in homologous and heterologous antigens and could be avoided by using different purified methods. The present study evaluated antigen fractions obtained from saline extracts of T. saginata metacestodes purified by affinity chromatography with jacalin or concanavalin A (ConA) lectins to detect IgG antibodies by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis to diagnose human NC. Serum samples were collected from 142 individuals: 40 of them were diagnosed with NC, 62 presented Taenia sp. and other parasites, and 40 were apparently healthy individuals. The jacalin- and ConA-unbound fractions demonstrated sensitivity and specificity higher than those of bound fractions. Among unbound fractions, ConA demonstrated statistically higher sensitivity and specificity by ELISA (90% and 93.1%, respectively). By immunoblot assay, the 64- to 68-kDa component from the ConA-unbound fraction showed 100% sensitivity and specificity, making this component suitable for use as a specific antigen for diagnosis of NC. To our knowledge, this is the first report showing the relevance of using the unbound ConA fraction of T. saginata metacestodes to diagnose NC. In conclusion, the results obtained herein clearly demonstrate that antigenic fractions without affinity to ConA, obtained from T. saginata metacestodes, are an important source of specific peptides and are efficient in the diagnosis of NC when tested by immunoblot assay.

Applications of heparin and heparan sulfate microarrays

Carbohydrate microarrays have become crucial tools for revealing the biological interactions and functions of glycans, primarily because the microarray format enables the investigation of large numbers of carbohydrates at a time. Heparan sulfate (HS) and heparin are the most structurally complex glycosaminoglycans (GAGs). In this chapter, we describe the preparation of a small library of HS/heparin oligosaccharides, and the fabrication of HS/heparin microarrays that have been used to establish HS/heparin-binding profiles. Fibroblast growth factors (FGFs), natural cytotoxicity receptors (NCRs), and chemokines were screened to illuminate the very important biological functions of these glycans.

Purification and mass spectrometric characterization of Sesbania aculeata (Dhaincha) stem lectin

A glucose specific lectin (STA) was isolated from Sesbania aculeata stem by using Sephadex G-50 affinity column chromatography. The lectin is a glycoprotein having 29 kDa subunit molecular weight. Two dimensional gel electrophoresis analysis revealed that the lectin existed in two isomeric forms with varied carbohydrate content as analyzed by high performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and N-terminal sequence (LDSLSFTYNNFE) analysis of this lectin showed 95% homology with stem lectin SL-I (accession no. AJ585523) from peanut plant. The nucleotide sequence of the lectin (STA) was submitted to the gene bank (accession no. EU263636).

A glycoprotein extracted from golden oyster mushroom Pleurotus citrinopileatus exhibiting growth inhibitory effect against U937 leukemia cells

Mushrooms have become popular sources of natural antitumor, antiviral, antibacterial, antioxidative, and immunomodulatory agents. Golden oyster mushroom, Pleurotus citrinopileatus , is a common mushroom in oriental countries for human consumption. We isolated a functional protein (PCP-3A) from the fresh fruiting body of this mushroom. The isolation procedure included ammonium sulfate fractionation, DEAE-Sepharose CL-6B ion exchange chromatography, and Sephacryl S-300 gel filtration. Electrophoresis demonstrated that PCP-3A is a glycoprotein composed of 10 subunits, each approximately 45.0 kDa in size. In vitro cell study showed that PCP-3A at a concentration about 12.5 microg/mL inhibits the proliferation of human tumor cell line U937, in a time- dependent manner (24, 48, and 72 h). It failed to agglutinate rabbit and human erythrocytes, excluding its possibility from being a lectin. Flow cytometry revealed that it is capable of inhibiting the growth of U937 cells by way of S phase arrest and apoptotic induction. We suggest that PCP-3A is worth further investigating for antitumor use.

Intracellular protein delivery by glucose-coated polymeric beads

Glucose-coated polymeric beads have been prepared and applied to delivery of a model protein (enhanced green fluorescent protein) into mouse embryonic stem cells as well as Hela cells.

Optimization of culture conditions and characterization of a new lectin from Aspergillus niger

Lectin activity was determined on solidified medium containing agar and in broth cultures of Aspergillus niger. The fungus was found to express 16 times higher activity in broth cultures, when grown in a medium adjusted to pH 5.5 at 30°C under stationary condition. Lectin activity was found to be expressed by 6-day-old mycelial cultures with maximum activity being expressed on 9th day of incubation. The crude lectin (total titer 1280) was found to be precipitated at 50% saturation of ammonium sulphate with 2.4-fold purifi cation and 83% yield in the precipitate. The partially purifi ed lectin was found to agglutinate all human, rat, mice and pig erythrocytes. It was found to have a strong binding affinity to mucin, asialofetuin and inulin.

Ox erythrocyte agglutinability. 4. The effect of neuraminidase treatment on the agglutinability of cells and ghosts

1. The inherited differential agglutinability of cattle erythrocytes is shown to be similarly expressed on ghosts and intact cells. 2. Removal of virtually all sialic acid by prolonged neuraminidase treatment does not alter the agglutinability status of ghosts prepared from either high or low agglutinable cells. Hence the differing sialic acid content of the two cell types is not responsible for the differential agglutinability. 3. The significance of these findings with respect to other well defined agglutination systems and current theories of membrane structure is discussed.

CEL-I, an N-acetylgalactosamine (GalNAc)-specific C-type lectin, induces nitric oxide production in RAW264.7 mouse macrophage cell line

We found that CEL-I, a GalNAc-specific C-type lectin isolated from the marine invertebrate Holothuroidea (Cucumaria echinata), induces inducible nitric oxide synthase (iNOS) expression and NO production in RAW264.7 cells. The NO production was inhibited by an iNOS inhibitor, L-NAME, but was not by a lipopolysaccharide (LPS) inhibitor, polymyxin B. In the presence of 0.1-M GalNAc, increased NO production by CEL-I-treated RAW264.7 cells was observed rather than the inhibition. Bovine serum albumin (BSA) significantly inhibited the CEL-I-induced NO production as well as the binding of FITC-labelled CEL-I on RAW264.7 cells. Three MAP kinase inhibitors (specific to extra-cellular regulated kinase, c-jun NH(2)-terminal kinase and p38 MAP kinase) inhibited CEL-I-induced NO production with different extents. Heat-treatment of CEL-I resulted in a decreased activity of CEL-I depending on the temperature. These results suggest that CEL-I induces NO production in RAW264.7 cells through the protein-cell interaction rather than the binding to the specific carbohydrate chains on the cell surface.

Defense Against Biological Weapons (Biodefense)

Biological warfare (germ warfare) is defined as the use of any disease-causing organism or toxin(s) found in nature as weapons of war with the intent to destroy an adversary. Though rare, the use of biological weapons has occurred throughout the centuries.

A novel C-type lectin from the shrimp Litopenaeus vannamei possesses anti-white spot syndrome virus activity

C-type lectins play key roles in pathogen recognition, innate immunity, and cell-cell interactions. Here, we report a new C-type lectin (C-type lectin 1) from the shrimp Litopenaeus vannamei (LvCTL1), which has activity against the white spot syndrome virus (WSSV). LvCTL1 is a 156-residue polypeptide containing a C-type carbohydrate recognition domain with an EPN (Glu(99)-Pro(100)-Asn(101)) motif that has a predicted ligand binding specificity for mannose. Reverse transcription-PCR analysis revealed that LvCTL1 mRNA was specifically expressed in the hepatopancreas of L. vannamei. Recombinant LvCTL1 (rLvCTL1) had hemagglutinating activity and ligand binding specificity for mannose and glucose. rLvCTL1 also had a strong affinity for WSSV and interacted with several envelope proteins of WSSV. Furthermore, we showed that the binding of rLvCTL1 to WSSV could protect shrimps from viral infection and prolong the survival of shrimps against WSSV infection. Our results suggest that LvCTL1 is a mannose-binding C-type lectin that binds to envelope proteins of WSSV to exert its antiviral activity. To our knowledge, this is the first report of a shrimp C-type lectin that has direct anti-WSSV activity.

Glycoconjugate expression of sinus mucosa in chronic rhinosinusitis: a lectin histochemical study

BACKGROUND

Glycoproteins are responsible for the rheological properties of the mucus. Changes in mucus viscosity may interfere with mucociliary clearance, leading to stasis and aggravation of chronic rhinosinusitis (CRS). The purpose of this study was to assess the composition and concentration of various sinus mucosa glycoproteins in normal and chronically inflamed sinuses.

METHODS

A semiquantitative scoring system was used to express the binding intensity of 10 lectins to 6 carbohydrates (galactose, sialic acid, N-acetylglucosamine, N-acetylgalactosamine [GalNac] [corrected], fucose, mannose) residing in the sinus mucosa of patients with CRS (N = 20) and normal controls (N = 10).

RESULTS

The mean CT score, compatible with extensive sinus disease, was 13.9 +/- 6.7. All six carbohydrates were found in the epithelium and submucosal glands of patients and controls. Peanut agglutinin staining showed significantly higher concentration of disaccharide galactose beta 1,3 GalNac [corrected] in epithelial goblet cells and in submucosal mucous and mixed glands of patients compared with that of controls (p = 0.01, p = 0.03, and p = 0.018, respectively). The epithelial glycocalyx of patients was also significantly more abundant in fucose and in GalNac [corrected] (p = 0.015, and p < 0.001, respectively).

CONCLUSION

Glycoconjugate expression of the sinus mucosa in CRS is markedly altered in extensive inflammatory conditions. The increased concentration of galactose beta 1,3 GalNac [corrected] in CRS probably contributes to the high viscosity of the nasal mucus and interferes with normal mucociliary clearance. Exposed peripheral galactose residues may serve as attachment receptor sites for pathogenic bacteria. Means interfering with the ability of bacteria to adhere to specific receptors on host tissues warrant additional research.

Odorranalectin is a small peptide lectin with potential for drug delivery and targeting

Background

Lectins are sugar-binding proteins that specifically recognize sugar complexes. Based on the specificity of protein–sugar interactions, different lectins could be used as carrier molecules to target drugs specifically to different cells which express different glycan arrays. In spite of lectin's interesting biological potential for drug targeting and delivery, a potential disadvantage of natural lectins may be large size molecules that results in immunogenicity and toxicity. Smaller peptides which can mimic the function of lectins are promising candidates for drug targeting.

Principal Findings

Small peptide with lectin-like behavior was screened from amphibian skin secretions and its structure and function were studied by NMR, NMR-titration, SPR and mutant analysis. A lectin-like peptide named odorranalectin was identified from skin secretions of Odorrana grahami. It was composed of 17 aa with a sequence of YASPKCFRYPNGVLACT. L-fucose could specifically inhibit the haemagglutination induced by odorranalectin. ¹²⁵I-odorranalectin was stable in mice plasma. In experimental mouse models, odorranalectin was proved to mainly conjugate to liver, spleen and lung after i.v. administration. Odorranalectin showed extremely low toxicity and immunogenicity in mice. The small size and single disulfide bridge of odorranalectin make it easy to manipulate for developing as a drug targeting system. The cyclic peptide of odorranalectin disclosed by solution NMR study adopts a β-turn conformation stabilized by one intramolecular disulfide bond between Cys6-Cys16 and three hydrogen bonds between Phe7-Ala15, Tyr9-Val13, Tyr9-Gly12. Residues K5, C6, F7, C16 and T17 consist of the binding site of L-fucose on odorranalectin determined by NMR titration and mutant analysis. The structure of odorranalectin in bound form is more stable than in free form.

Conclusion

These findings identify the smallest lectin so far, and show the application potential of odorranalectin for drug delivery and targeting. It also disclosed a new strategy of amphibian anti-infection.

Amino acids of ricin and its polypeptides

Ricin and its corresponding polypeptides (A & B chain) were purified from castor seed. The molecular weight of ricin subunits were 29,000 and 28,000 daltons. The amino acids in ricin determined were Asp45 The22 Ser40 Glu53 Cys4 Gly96 His5 Ile21 Leu33 Lys20 Met4 Phe13 Pro37 Tyr11 Ala45 Val23 Arg20 indicating that ricin contains approximately 516 amino acid residues. The amino acids of the two subunits of ricin A and B chains were Asp23 The12 Ser21 Glu29 Cys2 Gly48 His3 Ile12, Leu17 Lys10 Met2 Phe6 Pro17 Tyr7 Ala35 Val13 Arg13 while in B chain the amino acids were Asp22 The10 Ser19 Glu25 Cys2 Gly47 His1 Ile10, Leu15 Lys11 Met1 Phe7 Pro6 Tyr5 Ala32Val11 Arg10. The total helical content of ricin came around 53.6% which is a new observation.

Adsorption of concanavalin A and lentil lectin on platinum electrodes followed by electrochemical impedance spectroscopy: Effect of protein state

Adsorption of concanavalin A and lentil lectin on platinum electrode was investigated through electrochemical impedance spectroscopy and cyclic voltammetry. By using ferro/ferricyanide system to probe the electrochemical interface it was possible to model the EIS data with a simple equivalent circuit. The blocking effect for electron transfer reactions observed with these proteins, indicated that they readily adsorb on platinum surface and that the degree of adsorption is related to the state of the proteins. When the proteins are in the presence of divalent cations (Ca(2+) and Mn(2+)) they adsorb less strongly than in their absence. There is also evidence that at least convanavalin A retains its biological activity in the adsorbed state.

MOLECULAR CHARACTERIZATION OF THE LECTIN, BRYOHEALIN, INVOLVED IN PROTOPLAST REGENERATION OF THE MARINE ALGA BRYOPSIS PLUMOSA (CHLOROPHYTA)(1)

When a coenocytic cell of the green alga Bryopsis plumosa (Hudson) C. Agardh was cut open and the cell contents expelled, the cell organelles agglutinated rapidly in seawater to form protoplasts. This process was mediated by a lectin, Bryohealin. The full sequence of the cDNA encoding Bryohealin was obtained, which consisted of 1,101 base pairs (bp), with 24 bp of 5' untranslated region (UTR) and 201 bp of 3' UTR. It had an open reading frame (ORF) of 771 bp encoding 257 amino acid residues. A signal peptide consisted of 22 amino acids presented before the start codon of Bryohealin, indicating that this lectin was a vacuolar (storage) protein. The C-terminal sequence of Bryohealin was composed of antibiotic domains, suggesting that this lectin could perform two functions: (i) aggregation of cell organelles in seawater and (ii) protection from bacterial contamination for successful protoplast regeneration. The BLAST search result showed that Bryohealin had little sequence homology with any known plant lectins, but rather resembled animal lectins with fucolectin domains. The expression of recombinant Bryohealin (rBryohealin) was obtained in the Escherichia coli system.

Signaling molecules involved in production and regulation of IL-1β by murine peritoneal macrophages in vitro on treatment with Concanavalin A

In the present study we report the activation of murine peritoneal macrophages in vitro on treatment with Concanavalin A (ConA). ConA (10 microg/ml) treatment of macrophages resulted in the transcription of IL-1beta gene at 16 h and maximum production of IL-1beta at 24 h. To investigate the signaling molecules involved in the production of IL-1beta different pharmacological inhibitors were used. It was observed that genestein, wortmannin, H-7, TMB-8, PD98059, SB202190, and tyrophostin (AG490) down regulated the expression of IL-1beta. These observations suggested the involvement of tyrosine kinase, PI3 kinase, protein kinase C, p42/44, p38, Ca(++) and JAK2 signaling molecules in ConA induced production of IL-1beta by macrophages. Maximum protein tyrosine kinase activity and expression of PI3K in macrophages was seen at 5 min, PKC activity and Ca(++) release was found at 10 min after ConA treatment. Maximum expression of phospho-JAK2 at 2.5-5 min, phospho-p42/44 at 5-60 min, phospho-p38 at 15-30 min, phospho-IkappaB and phospho-Stat1 at 30-60 min and phospho-ELK1, c-Fos, phospho-Stat3 at 60 min of ConA treatment was observed. Pharmacological inhibitors were also used to check the cascade of activation of tyrosine kinase, PKC, PI3 kinase, p42/44, p38, JAK kinase and release of Ca(++) from intracellular storage to sort out the signaling pathways involved in the release of IL-1beta by macrophages on treatment with ConA in vitro.

Changes of glycoconjugate expression in nasal respiratory mucosa of rats exposed to welding fumes

To investigate the effects of welding fumes on the glycoconjugates in nasal respiratory mucosa, male Sprague-Dawley rats were exposed to manual metal arc stainless steel (MMA-SS) welding fumes at a concentration of 56-76 mg/m(3) total suspended particulate for 2 h/day in an inhalation chamber for 90 days. During the exposure period, the experimental animals were sacrificed after 2 h and 15, 30, 60, and 90 days of exposure; then sections were examined using lectin histochemistry. Some remarkable changes, such as destroyed cilia, desquamation and mucification of epithelial cells, and destruction of nasal septal glands, were seen in the welding fume-exposed groups. Specific changes in the lectin binding patterns were also observed in the welding fume-exposed rats. The Ricinus communis agglutinin-I (RCA-I) staining of the cilia and columnar cells increased slightly when compared with the unexposed rats. The RCA-I and Ulex europaeus agglutinin-I (UEA-I) staining of the goblet cells also increased as the exposure continued. The mucigenous epithelial cells reacted with Bandeiraea simplicifolia lectin-I (BSL-I), RCA-I, and succinylated wheat germ agglutinin A (sWGA) after 15 days of exposure, which was not visible in the control group. The dorsal septal glands exhibited an affinity with peanut agglutinin (PNA), BSL-I, and RCA-I, which was also not visible in the control group. The affinity for Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), PNA, sWGA, BSL-I, and UEA-I in the ventral septal glands of the welding fume-exposed groups tended to increase, whereas the concanavalin A (Con A) reactivity in the dorsal septal glands decreased slightly. In conclusion, it was assumed that the changes in the glycoconjugate residues in the nasal respiratory mucosa of the welding fume-exposed rats represented important components of defense mechanisms against the toxicants in the welding fumes.

Production of TNF-alpha, IL-1beta, IL-12 and IFN-gamma in murine peritoneal macrophages on treatment with wheat germ agglutinin in vitro: involvement of tyrosine kinase pathways

Treatment of macrophages with various doses of wheat germ agglutinin (WGA) for different time intervals resulted in enhanced expression of TNF-alpha, IL-1beta, IL-12 and IFN-gamma. The maximum expressions were observed at 24 h with 100 ng/ml of WGA. Enhanced transcription of cytokines TNF-alpha, IL-1beta, IL-12, and IFN-gamma was observed at 16 h of WGA treatment by RT-PCR. Pharmacological inhibitor of tyrosine kinase, PI3 kinase, protein kinase C, p42/44, p38, JNK and intracellular calcium immobilizing agent down regulated the WGA induced expression of cytokines TNF-alpha, IL-1beta, IL-12 and IFN-gamma. Maximum protein tyrosine kinase activity in macrophages was seen at 5 min of WGA treatment. Maximum cytosolic Ca++ was observed at 10 min of WGA treatment. WGA treated macrophages showed maximum activation of protein kinase C (PKC) and PI3 kinase at 10 min, p42/44, p38 at 15 min and JNK at 30 min. Transcription factor ELK1 was activated at 60 min and IêB, c-Fos and c-Jun at 30 min of WGA treatment. The pharmacological inhibitors were also used to check the cascade of activation of tyrosine kinase, PKC, PI3 kinase, p42/44, p38, JNK and release of calcium from intracellular storage to sort out the signal pathways involved in the release of TNF-alpha, IL-1beta, IL-12, and IFN-gamma by macrophages on treatment with WGA in vitro.

Capacitive biosensor for detection of endotoxin

A capacitive biosensor for the detection of bacterial endotoxin has been developed. Endotoxin-neutralizing protein derived from American horseshoe crab was immobilized to a self-assembled thiol layer on a biosensor transducer (Au). Upon injection of a sample containing endotoxin, a decrease in the observed capacitive signal was registered. Endotoxin could be determined under optimum conditions with a detection limit of 1.0 x 10(-13) M and linearity ranging from 1.0 x 10(-13) to 1.0 x 10(-10) M. Good agreement was achieved when applying endotoxin preparations purified from an Escherichia coli cultivation to the capacitive biosensor system, utilizing the conventional method for quantitative endotoxin determination, the Limulus amebocyte lysate test as a reference. The capacitive biosensor method was statistically tested with the Wilcoxon signed rank test, which proved the system is acceptable for the quantitative analysis of bacterial endotoxin (P<0.05).

Allergenicity of soybean: new developments in identification of allergenic proteins, cross-reactivities and hypoallergenization technologies

Soybean is considered one of the "big eight" foods that are believed to be responsible for 90% of all allergenic reactions. Soy allergy is of particular importance, because soybeans are widely used in processed foods and, therefore, represent a particularly insidious source of hidden allergens. Although significant advances have been made in the identification and characterization of soybean allergens, scientists are not completely certain about which proteins in soy cause allergic reactions. At least 16 allergens have been identified. Most of them, as with other plant food allergens, have a metabolic, storage, or protective function. These allergens belong to protein families which have conserved structural features in relation with their biological activity, which explains the wide immunochemical cross-recognition observed among members of the legume family. Detailed analysis of the structure-allergenicity relationships has been hampered by the complexity and heterogeneity of soybean proteins. A variety of technological approaches have been attempted to decrease soybean allergenicity. This paper provides a comprehensive review of the current body of knowledge on the identification and characterization of soybean allergens, as well as an update on current hypoallergenization techniques.

Molecular dynamics simulations of pea (Pisum sativum) lectin structure with octyl glucoside detergents: the ligand interactions and dynamics

The mitogenic pea (Pisum sativum) lectin is a legume protein of non-immunoglobulin nature capable of specific recognition of glucose derivatives without altering its structure. Molecular dynamics simulations were performed in a realistic environment to investigate the structure and interaction properties of pea lectin with various concentrations of n-octyl-beta-d-glucopyranoside (OG) detergent monomers distributed inside explicit solvent cell. In addition, the diffusion coefficients of the ligands (OG, Ca2+, Mn2+, and Cl-) and the water molecules were also reported. The structural flexibility of the lectin was conserved in all simulations. The self-assembly of OG monomers into a small micelle at the hydrophobic site of the lectin was noticed in the simulation with 20 OG monomers. The interaction energy analysis concludes that the lectin was appropriately termed an adaptive structure. One or rarely two binding sites were observed at an instant in each simulation that were electrostatically favoured for the OG to interact with the surface amino acid residues. Enhanced binding of OG to the pea lectin was quantified in the system containing only Ca2+ divalent ions. Interestingly, no binding was observed in the simulation without divalent ions. Furthermore, the lectin-ligand complex was stabilized by multiple hydrogen bonds and at least one water bridge. Finally, the work was also in accordance with the published work elsewhere that the simulations performed with different initial conditions and using higher nonbonded cutoffs for the van der Waals and electrostatic interactions provide more accurate information and clues than the single large simulation of the biomolecular system of interest.

Biomolecular characterisation of leucocytes by infrared spectroscopy

Over the last 15 years, infrared (IR) spectroscopy has developed into a novel and powerful biomedical tool that has multiple applications in the field of haematology. By revealing subtle alterations in both the conformation and concentration of key macromolecules, such as DNA, protein and lipids, IR spectroscopy has been employed to investigate multiple aspects of leucocyte physiology. IR spectroscopy has been used, for example, to diagnose and prognose leukaemia; to characterise differentiation and apoptotic processes; to predict drug sensitivity and resistance in leukaemic patients undergoing chemotherapy; to monitor the response of leucocytes to chemotherapy and to perform human leucocyte antigen matching for bone marrow transplant patients. Such studies have provided insight into pathogenic mechanisms underlying specific leucocyte disorders, especially leukaemia. While it is likely to be some considerable time before IR spectroscopy is sufficiently developed to displace the established technologies, IR spectroscopy has the potential to become a valuable analytic tool in basic and clinical haematology.