Isolation and characterization of a new β-galactose-specific lectin from the sea worm Chaetopterus variopedatus

The hidden biotechnological potential of marine invertebrates: The Polychaeta case study

Marine biotechnology is under the spotlight, as researchers and industrialists become aware that bioprospecting through the oceans' vast biodiversity can replace the painstaking process of designing synthetic compounds. Millions of years of Natural Selection provided an almost inexhaustible source of marine products that can interfere with specific bioprocesses while being cost-effective, safer and more environmentally friendly. Still, the number of commercial applications of marine compounds, especially from eumetazoans, can seem disappointing. In most part, this results from the challenges of dealing with an immense biodiversity and with poorly known organisms with uncanny physiology. Consequently, shifting the current perspective from descriptive science to actually proposing applications can be a major incentive to industry. With this in mind, the present review focuses on one of the least studied but most representative group of marine animals: the Polychaeta annelids. Occupying nearly every marine habitat, from the deep sea to the intertidal, they can offer a wide array of natural products that are just beginning to be understood, showing properties compatible with anaesthetics, fluorescent probes, and even antibiotics and pesticides, for instance. Altogether, they are a showcase for the ocean's real biotechnological deterrent, albeit our still wispy knowledge on this vast and ancient environment.

Antiviral lectins: Selective inhibitors of viral entry

Many natural lectins have been reported to have antiviral activity. As some of these have been put forward as potential development candidates for preventing or treating viral infections, we have set out in this review to survey the literature on antiviral lectins. The review groups lectins by structural class and class of source organism we also detail their carbohydrate specificity and their reported antiviral activities. The review concludes with a brief discussion of several of the pertinent hurdles that heterologous proteins must clear to be useful clinical candidates and cites examples where such studies have been reported for antiviral lectins. Though the clearest path currently being followed is the use of antiviral lectins as anti-HIV microbicides via topical mucosal administration, some investigators have also found systemic efficacy against acute infections following subcutaneous administration.

Absolute Configuration and Body Part Distribution of the Alkaloid 6-epi-Monanchorin from the Marine Polychaete Chaetopterus variopedatus

As a result of the first study on secondary metabolites from the cosmopolitan bioluminescent marine tube polychaete Chaetopterus variopedatus, a new bicyclic guanidine alkaloid, 6- epi-monanchorin (1), along with the previously known monanchorin (2) were isolated. The structure of 1 was elucidated by spectroscopic and chemical methods, including a cleavage of the C1–O7 bond to obtain a secondary alcohol (3), which was used to determine the absolute configurations by Mosher's method. It was found that 1 and 2 were mainly accumulated in a secreted mucus special organ of the worm (food net), where green and blue-green microalgae were detected. A biosynthetic pathway to 6- epi-monanchorin and monanchorin from dietary polyenic fatty acid precursors was proposed.

Lectins of marine hydrobionts

Data from the literature and results of our research on lectins isolated from some kinds of marine hydrobionts such as clams, ascidians, sea worms, sponges, and algae are presented in this review. Results of comparative analysis of the basic physicochemical properties and biological activity of lectins isolated from various sources are discussed.

A new lectin from the sea worm Serpula vermicularis: isolation, characterization and anti-HIV activity

A GlcNAc-specific lectin was isolated from the sea worm Serpula vermicularis (SVL) (Annelida) and purified by ion-exchange, affinity and gel permeation chromatography. SVL was a homotetrameric protein with native molecular mass of about 50 kDa, and consisted of identical subunits of 12.7 kDa. The carbohydrate content of 1.9% suggested that the lectin was a glycoprotein, and mainly composed by aspartic and glutamic acids, glycine, valine and serine; with relatively lower content of basic amino acids and cysteine. The first 15 residues of the N-terminal region were determined as ADTPCQMLGSRYGWR. It was stable at pH 6-9 and at temperatures up to 40 degrees C. SVL was Ca(2+)-independent lectin that agglutinated native and trypsinized human erythrocytes. Hapten inhibition studies indicated that SVL showed binding specificity only for N-acetyl-d-glucosamine and its derivatives among the monosaccharides tested and required the presence of hydroxyl group at the C-3 of GlcNAc. The presence of hydrophobic p-nitrophenyl aglycone improved inhibitory potency of N-acetyl-d-glucosamine. Ovomucoid and ovalbumin were found to be inhibitors among the glycoproteins used for inhibition assay. The anti-HIV-1 (human immunodeficiency virus) activity of SVL in vitro was determined: SVL inhibited the production of viral p24 antigen and cytopathic effect induced by HIV-1. The EC(50) values were 0.23 and 0.15 microg x mL(-1) respectively.

A beta-galactose-specific lectin isolated from the marine worm Chaetopterus variopedatus possesses anti-HIV-1 activity

A 30 kDa beta-galactose-specific lectin named CVL was isolated from the polychaete marine worm Chaetopterus variopedatus (Annelida) and its anti-HIV-1 activity in vitro was determined. Results showed that CVL inhibited cytopathic effect induced by HIV-1 and the production of viral p24 antigen. The EC(50) values were 0.0043 and 0.057 microM, respectively. Time-of-addition analysis of anti-HIV-1 activity indicated its action was at the early stage of virus replication. CVL could blocked the cell-to-cell fusion process of HIV infected and uninfected cells with an EC(50) of 0.073 microM. The inhibition of HIV-1 entry into host cells was demonstrated by using fluorescence-based real-time quantify PCR. At CVL concentration of 0.33 microM and 0.07 microM, 86% and 21% virus attachment were blocked, respectively. The anti-HIV-1 action of CVL might relate to blockade of HIV-1 entry into cells.

A galactose-specific lectin from the red marine alga Ptilota filicina

A lectin from the red marine alga Ptilota filicina (PFL) was isolated by affinity chromatography on cross-linked guar gum. PFL agglutinated native and papain-treated human erythrocytes with preference for type O erythrocytes. The lectin was inhibited by galactose and its derivatives. The most potent inhibitors were p-Nitrophenyl-N-acetyl-alpha- and beta-D-galactosaminide. Porcine stomach mucin, bovine submaxillary gland mucin and asialo bovine mucin were also inhibitory. The M(r) of PFL, determined by gel filtration, was 56,900. SDS-PAGE gave one band with a subunit M(r) of 19,320, indicating the native protein to be a trimer of apparently identical subunits. PFL was shown to be rich in acidic and hydroxyl amino acids but low in basic amino acids. The ten N-terminal amino acids were Asx-Thr-Lys-Thr-Leu-Leu-Ala-.

Isolation and characterization of new GalNAc/Gal-specific lectin from the sea mussel Crenomytilus grayanus

A lectin, Crenomytilus grayanus (CGL), was purified from sea mussel C. grayanus by affinity chromatography on acid-treated Sepharose 6B and following gel filtration on Sephacryl S-200. Molecular weight of the lectin obtained was determined by SDS-PAGE to be 18,000, independent of the presence or absence of beta-mercaptoethanol. CGL was found to agglutinate all types of the human erythrocytes together with mouse and rabbit. In hemagglutination inhibition assays, N-acetyl-D-galactosamine, D-galactose, and D-talose were the most potent inhibitors among the monosaccharides tested. Out of the oligosaccharides containing nonreducing terminal D-galactose, melibiose, and raffinose were found to be strong inhibitors. On the other hand, among the glycoproteins, asialo-BSM was the best inhibitor. The hemagglutinating activity of CGL was independent of the divalent cations Ca2+ and Mg2+. Significant CGL activity was observed between pH 8-10.

D-galactoside-specific lectins from the body wall of an echiuroid (Urechis unicinctus) and two annelids (Neanthes japonica and Marphysa sanguinea)

Lectins recognizing D-galactosides were purified from the body wall of an echiuroid; Urechis unicinctus and two annelids; Neanthes japonica and Marphysa sanguinea, with single step lactosyl-agarose affinity column chromatography. SDS-PAGE under reduced and non-reduced conditions showed that U. unicinctus lectin had a major (36 kDa) and two minor (40 and 14 kDa) proteins, and that N. japonica lectin and M. sanguinea lectin had single 33 and 35 kDa proteins, respectively. Lectins were solubilized in the presence of lactose from tissues, and all polypeptides were shown to have sugar binding activity. The antisera raised against U. unicinctus lectin and N. japonica lectin crossreacted with each other but did not crossreact with bull frog (Rana catesbeiana) egg galectin-1 or a D-galactoside-specific lectin purified from sea urchin (Anthocidaris crassispina) eggs. These echiuroid and annelid lectins are immunologically similar, but distinct from members of the vertebrate galectin family.