The immunostimulatory activity and stability of grass carp (Ctenopharyngodon idellus) roe lectin

Effect of Fortified Feed with Phyto-Extract on the First Physical Barrier (Mucus) of Labeo rohita

Simple Summary

Pathogens of fish are a serious issue faced by farmers and a great threat to the country’s economy. Overuse of antibiotics leads to antibiotic-resistant strains of the bacterial pathogens; residues of the antibiotics also accumulate in the tissue of the fish and are responsible for environmental problems. Therefore, the use of antibiotic alternatives should be explored as a new approach to immunotherapy to prevent or to cure preexisting infections. Previous research has concluded that the use of herbal extracts enhances the immunity of fish against several fish pathogens such as bacteria and other protozoon parasites. This study aimed to evaluate the effect of two different fortified feeds with different concentrations of Withania coagulans and Zingiber officinale on the fish mucus of Labeo rohita. The mucus was tested against five pathogenic bacteria in-vitro while fish was tested against the ectoparasite Lernaea (in-vivo). Our result showed that Z. officinale proves an efficient immune stimulator for the L. rohita against the tested organism (both in vivo and in vitro). Hence, it can be used as an effective solution against the emerging diseases of cultured fish.

Abstract

The aim of the current study was to assess the effect of two different fortified feeds with different concentrations of two important medicinal plants (Withania coagulans and Zingiber officinale) on the mucosal immunity of Labeo rohita. After a dietary intervention, mucus was tested against five pathogenic bacteria (in-vitro), while experimental fish were tested against the ectoparasite (Lernaea) (in-vivo). Our results revealed that all fish groups fed with different concentrations (1, 1.5, and 2%) of Z. officinale had low molecular weight proteins and did not develop any significant signs of parasitic infection, with low mortality rate; whereas the groups that were fed with W. coagulans (particularly with 1% and 2%), including a control group, developed rapid signs of infection with high mortality rate. The highest hemagglutination titer value was recorded for the fish fed with 1% and 1.5% of Z. officinale. The lowest value was found for the fish fed with 2% of W. coagulans. The mucus of all fish of fortified groups was active and inhibited the growth of tested bacterial pathogens as compared to the control group. Further, Z. officinale groups showed greater efficacy against bacteria as compared to the W. coagulans groups. In conclusion, Z. officinale can be considered as a potential and functional ingredient in aquaculture feed. Furthermore, future studies should be conducted to investigate more details on the subject.

Lectins, Interconnecting Proteins with Biotechnological/Pharmacological and Therapeutic Applications

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.

Three novel B-type mannose-specific lectins of Cynoglossus semilaevis possess varied antibacterial activities against Gram-negative and Gram-positive bacteria

Lectins are a group of sugar-binding proteins that are important factors of the innate immune system. In this study, we examined, in a comparative manner, the expression and function of three Bulb-type (B-type) mannose-specific lectins (named CsBML1, CsBML2, and CsBML3) from tongue sole. All three lectins possess three repeats of the conserved mannose binding motif QXDXNXVXY. Expression of CsBML1, CsBML2, and CsBML3 was most abundant in liver and upregulated by bacterial infection. Recombinant (r) CsBML1, CsBML2, and CsBML3 bound to a wide arrange of bacteria in a dose-dependent manner and with different affinities. All three lectins displayed mannose-specific and calcium-dependent agglutinating capacities but differed in agglutinating profiles. rCsBML1 and rCsBML2, but not rCsBML3, killed target bacteria in vitro and inhibited bacterial dissemination in fish tissues in vivo. These results indicate for the first time that in teleost, different members of B-type mannose-specific lectins likely play different roles in antibacterial immunity.

Isolation and characterization of a novel lectin from the edible mushroom Stropharia rugosoannulata

To date, only a few steroids have been isolated from the mushroom Stropharia rugosoannulata which can be cultivated. In this paper, a novel lectin (SRL) with a molecular weight of 38 kDa, and a unique IKSGVYRIVSWQGALGPEAR N-terminal sequence was isolated from S. rugosoannulata, which represents the first protein isolated from the mushroom. The purification methods included (NH₄)₂SO₄ precipitation, ion exchange chromatography on CM-cellulose, Q-Sepharose, and SP-Sepharose, and gel- filtration on Superdex-75. The lectin was adsorbed on all three types of ion exchangers and was purified more than 450-fold. The lectin was stable below 70 °C (with half of the activity preserved at 80 °C), and in the presence of NaOH and HCl solutions up to a concentration of 12.5 mM and 25 mM, respectively. The hemagglutinating activity of SRL was inhibited by inulin. Cd²⁺ and Hg²⁺ ions strongly reduced the hemagglutinating activity at concentrations from 1.25 mM to 10 mM. SRL exhibited anti-proliferative activity toward both hepatoma Hep G2 cells and leukemia L1210 cells, with an IC₅₀ of 7 μM and 19 μM, respectively. The activity of HIV-1 reverse transcriptase could also be inhibited by SRL, with an IC₅₀ of 10 μM.

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

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.

Structural characterization and antitumor and mitogenic activity of a lectin from the gill of bighead carp (Aristichthys nobilis)

In this study, we investigated the gross structure, secondary structure, and antitumor and mitogenic activity of GANL, a lectin from the gill of bighead carp (Aristichthys nobilis). We used infrared spectroscopy, β-elimination, and circular dichroism spectroscopy to determine the structure of GANL. We measured antiproliferation activity against six human tumor cell lines and mitogenic activity against murine splenocytes using the MTT assay. Based on infrared spectroscopy and β-elimination, we conclude that GANL is a glycoprotein. The protein and carbohydrate moieties are joined by O-glycosidic linkage. A circular dichroism spectroscopic analysis revealed that the secondary structure of GANL consists of α-helices (34.8 %), β-sheets (12.1 %), β-turns (24.5 %), and unordered structures (33.0 %). GANL exerted potent antitumor activity against the HeLa cell line (IC(50) = 11.86 μg/mL) and a mitogenic effect on murine splenocytes in the MTT assay. GANL, a lectin that is isolated from the gills of bighead carp, is a glycoprotein with potent antitumor and mitogenic activity.

Immunomodulatory response of mice splenocytes induced by RcaL, a lectin isolated from cobia fish (Rachycentron canadum) serum

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.

Diversified carbohydrate-binding lectins from marine resources

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

Purification and characterization of a mannose recognition lectin from Oreochromis niloticus (tilapia fish): cytokine production in mice splenocytes

The aim of this work was to purify and partially characterize a mannose recognition lectin from Nile tilapia (Oreochromis niloticus) serum, named OniL. OniL was isolated through precipitation with ammonium sulfate and affinity chromatography (Concanavalin A-Sepharose 4B). In addition, we evaluated carbohydrate specificity, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profiles, and in vitro immunomodulatory activity on mice splenocyte experimental cultures through cytotoxic assays and cytokine production. The ammonium sulfate fraction F2 showed the highest specific hemagglutinating activity (331) and was applied to affinity matrix. Adsorbed proteins (OniL) were eluted with methyl-α-D: -mannopyranoside. OniL, a 17-kDa protein by SDS-PAGE constituted by subunits of 11 and 6.6 kDa, showed highest affinity for methyl-α-D: -mannopyranoside and D: -mannose. Immunological assays, in vitro, showed that OniL did not show cytotoxicity against splenocytes, induced higher IFN-γ production and lower IL-10 as well as nitrite release. In conclusion, OniL lectin was successfully purified and showed a preferential Th1 response in mice splenocytes.

Purification and characterization of a rhamnose-binding chinook salmon roe lectin with antiproliferative activity toward tumor cells and nitric oxide-inducing activity toward murine macrophages

In this study, a rhamnose-binding lectin from the roe of chinook salmon (Oncorhynchus tshawytscha) was purified and characterized, and its biological activities were examined in several model systems. Chinook salmon roe lectin had a molecular mass of 30 kDa and agglutinated rabbit and bovine erythrocytes. The hemagglutination activity of the lectin was not affected by metal ions. The lectin was stable up to 70 °C and between pH 4 and pH 11. Chinook salmon roe lectin did not exert antifungal activity toward the fungal species tested and did not exhibit mitogenic response toward mouse splenocytes up to a concentration of 5 mg/mL. The lectin had selective antiproliferative activity toward human breast cancer MCF-7 cells and hepatoma Hep G2 cells. It also induced the production of nitric oxide from mouse peritoneal macrophages. This is the first report that demonstrates these biological activities from chinook salmon roe lectin.

Purification and characterization of a novel lectin from the toxic wild mushroom Inocybe umbrinella

From the dried fruiting bodies of the toxic mushroom Inocybe umbrinella, a novel lectin with a molecular mass of 17 kDa has been isolated with about 160-fold purification. The purification protocol comprised ion exchange chromatography on DEAE-cellulose, and CM-cellulose, and gel filtration on Superdex 75. Among the carbohydrates tested, raffinose, d-melibiose, alpha-lactose and d(+)-galactose could inhibit the hemagglutinating activity of the lectin. The hemagglutinating activity was stable between 10 and 60 degrees C, in 12.5-100mM HCl, and in 50mM NaOH. The hemagglutinating activity was inhibited by Ca(2+), Mn(2+)and Mg(2+) ions, but was unaffected by Fe(3+), Zn(2+) and Al(3+) ions. The lectin inhibited HIV-1 reverse transcriptase with an IC(50) of 4.7+/-0.2 microM. Proliferation of tumor cells including hepatoma HepG2 cells and breast cancer MCF7 cells was inhibited by the lectin with an IC(50) of 3.5+/-0.2 microM and 7.4+/-0.3 micoM, respectively. The lectin has a unique N-terminal amino acid sequence, DGVLATNAVA. It did not exhibit antifungal activity. The present report is the first on an Inocybe lectin and represents one of the very few reports on lectins from toxic mushrooms.

Novel rhamnose-binding lectins from the colonial ascidian Botryllus schlosseri

In a full-length cDNA library from the compound ascidian Botryllus schlosseri, we identified, by BLAST search against UniProt database, five transcripts, each with complete coding sequence, homologous to known rhamnose-binding lectins (RBLs). Comparisons of the predicted amino acid sequences suggest that they represent different isoforms of a novel RBL, called BsRBL-1-5. Four of these isolectins were found in Botryllus homogenate after purification by affinity chromatography on acid-treated Sepharose, analysis by reverse-phase HPLC and mass spectrometry. Analysis of both molecular masses and tryptic digests of BsRBLs indicated that the N-terminal sequence of the purified proteins starts from residue 22 of the putative amino acid sequence, and residues 1-21 represent a signal peptide. Analysis by mass spectrometry of V8-protease digests confirmed the presence and alignments of the eight cysteines involved in the disulphide bridges that characterise RBLs. Functional studies proved the enhancing effect on phagocytosis of the affinity-purified material. Results are discussed in terms of phylogenetic relationships of BsRBLs with orthologous molecules from protostomes and deuterostomes.

Immunomodulatory activity of dioscorin, the storage protein of yam (Dioscorea alata cv. Tainong No. 1) tuber

The purified dioscorin from yam (Dioscorea alata L. cv. Tainong 1) tuber was previously reported (Hsu et al., 2002. J. Agric. Food Chem., 50, 6109-6113). In this report, we evaluated its immunomodulatory ability in vitro in the presence of polymyxin B (50 microg/ml) to eliminate lipopolysaccharide (LPS) contamination. Dioscorin (5-100 microg/ml) was able to stimulate nitric oxide production (expressed as nitrite concentrations) in RAW264.7 cells. The stimulation index on the phagocytosis of RAW264.7 cells against E. coli and the oxidative burst (determined by the intensity of rhodamine fluorescence) of RAW264.7 cells were both enhanced by different concentrations of dioscorin (5-100 microg/ml). The cytokine production, including IL-6, TNF-alpha, and IL-1beta in dioscorin-treated RAW264.7 cells or human monocytes, was measured in the cultured medium. Dioscorin (5-100 microg/ml) was found able to induce IL-6, TNF-alpha, and IL-1beta production in RAW264.7 cells and human monocytes. To evaluate the effects of dioscorin on the proliferation of spleen cells from BALB/c mice, phytohemagglutinin (PHA, 2 microg/ml) alone or PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml) was used to treat spleen cells for 24h. The stimulated proliferation index of splenic cells ranged from 1.38- to 1.48-fold of PHA alone for PHA mixed with different concentrations of dioscorin (10, 25, and 50 microg/ml). We suggest that the tuber storage protein of yam dioscorin functions as an immunomodulatory substance.

Isolation and characterization of l-rhamnose-binding lectin, which binds to microsporidian Glugea plecoglossi, from ayu (Plecoglossus altivelis) eggs

A rhamnose-binding lectin, named SFL, was isolated from the eggs of ayu (sweet fish, Plecoglossus altivelis) by affinity and ion-exchange chromatographies. SFL revealed 287 amino acid residues with 3 tandemly repeated domains, and contained 8 half-Cys residues in each domain. The lectin was shown to have a highly specific binding affinity to globotriaosylceramide (Gb3) by frontal affinity chromatography using 100 oligosaccharides. SFL was localized in several tissues and serum of both male and female ayu, such as gill, liver, ovary, testis, intestine, stomach, brain, kidney and serum. The lectin agglutinated the spores of the microsporidian Glugea plecoglossi, which is a pathogen of ayu. Although SFL bound to glycoproteins and glycolipids of G. plecoglossi spores, Gb3 could not be detected in either of them. The results suggest that SFL could interact with various glycoconjugates of pathogens to play a role in the adhesion of microorganisms invading in the body.

Purification, cloning and characterization of egg lectins from the teleost Tribolodon brandti

Three L-rhamnose-binding egg lectins, TBL1, TBL2 and TBL3, were isolated from the eggs of the Far East dace Tribolodon brandti by a combination of affinity chromatography on L-rhamnose-Sepharose 6B gel and reversed-phase HPLC. L-rhamnose is a common inhibitor of the purified lectins and strongly inhibited the hemagglutinating activity of TBL2 and TBL3, but less weakly that of TBL1. L-arabinose, which has the same hydroxyl group orientation at C2 and C4 as L-rhamnose, and D-galactose showed no inhibitory activity against TBL1 but showed weak inhibitory activity against TBL2 and TBL3. The open reading frames of the cDNAs of TBL1, TBL2 and TBL3 encoded for mature proteins of 207, 189, and 293 amino acid residues, respectively. A BLAST homology search showed that the TBLs have about 40% homology to the carbohydrate recognition domains of rhamnose-binding lectins in salmonid eggs. The tandem repeated domains present in TBL1, TBL2 and TBL3 were two, two and three, respectively. TBL2 was exclusively expressed in ovary, while TBL1 and TBL3 were expressed mainly in ovary and weakly in various tissues including gill, heart, kidney, liver, spleen and testis.

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

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.

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

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 degrees 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 1microM lectin. Proliferation of tumor cells including MBL2 cells, HeLa cells, and L1210 cells was inhibited by the lectin with an IC(50) of 2.5, 5, and 10 microM, 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.