A lactose-binding lectin from the marine sponge Cinachyrella apion (Cal) induces cell death in human cervical adenocarcinoma cells

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 IC(50) (10 μg/mL) for both trials and twice the IC(50) 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.     

Glycoconjugates Distribution during Developing Mouse Spinal Cord Motor Organizers

Background: The aim of this research was to study the distribution and changes of glycoconjugates particularly their terminal sugars by using lectin histochemistry during mouse spinal cord development. Methods: Formalin-fixed sections of mouse embryo (10-16 fetal days) were processed for lectin histochemical method. In this study, two groups of horseradish peroxidase-labeled specific lectins were used: N-acetylgalactosamine, including Dolichos biflorus, Wisteria floribunda agglutinin (WFA), Vicia villosa, Glycine max as well as focuse-binding lectins, including tetragonolobus, Ulex europaeus, and Orange peel fungus (OFA). All sections were counterstained with alcian blue (pH 2.5). Results: Our results showed that only WFA and OFA reacted strongly with the floor plate cells from early to late embryonic period of developing spinal cord. The strongest reactions were related to the 14, 15, and 16 days of tissue sections incubated with OFA and WFA lectins. Conclusion: The present study demonstrated that cellular and molecular differentiation of the spinal cord organizers is a wholly regulated process, and α-L-fucose, α-D-GalNAc, and α/β-D-GalNAc terminal sugars play a significant role during the prenatal spinal cord development.Key Words: Development, Glycoconjugates, Spinal cord     

An Update of Lectins from Marine Organisms: Characterization,Extraction Methodology,and Potential Biofunctional Applications

Lectins are a unique group of nonimmune carbohydrate-binding proteins or glycoproteins that exhibit specific and reversible carbohydrate-binding activity in a non-catalytic manner. Lectins have diverse sources and are classified according to their origins, such as plant lectins, animal lectins, and fish lectins. Marine organisms including fish, crustaceans, and mollusks produce a myriad of lectins, including rhamnose binding lectins (RBL), fucose-binding lectins (FTL), mannose-binding lectin, galectins, galactose binding lectins, and C-type lectins. The widely used method of extracting lectins from marine samples is a simple two-step process employing a polar salt solution and purification by column chromatography. Lectins exert several immunomodulatory functions, including pathogen recognition, inflammatory reactions, participating in various hemocyte functions (e.g., agglutination), phagocytic reactions, among others. Lectins can also control cell proliferation, protein folding, RNA splicing, and trafficking of molecules. Due to their reported biological and pharmaceutical activities, lectins have attracted the attention of scientists and industries (i.e., food, biomedical, and pharmaceutical industries). Therefore, this review aims to update current information on lectins from marine organisms, their characterization, extraction, and biofunctionalities.     

Cyclic Bis-1,3-dialkylpyridiniums from the Sponge Haliclona sp.

Eight novel cyclic bis-1,3-dialkylpyridiniums, as well as two known compounds from the cyclostellettamine class, were isolated from the sponge Haliclona sp. from Korea. Structures of these novel compounds were determined using combined NMR and FAB-MS/MS analyses. Several of these compounds exhibited moderate cytotoxic and antibacterial activities against A549 cell-line and Gram-positive strains, respectively. The structure-activity relationships of cyclostellettamines are discussed based on their bioactivities.     

Three-dimensional porous collagen/chitosan complex sponge for tissue engineering

A three-dimensional, porous collagen/chitosan complex sponge was prepared to closely simulate basic extracellular matrix (ECM) constitutes, collagen and glycosaminoglycan. The complex sponge was prepared by a lyophilization method and had the regular network with highly porous structure, suitable for cell adhesion and growth. The pores were well interconnected, and their distribution was fairly homogeneous. The complex sponge was crosslinked using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to increase its biological stability and enhance its mechanical properties. The crosslinking medium had a great effect on the inner structure of the sponge. The homogeneous, porous structure of the sponge was remarkably collapsed in an aqueous crosslinking medium. However, the morphology of the sponge remained almost intact in a water/ethanol mixture crosslinking milieu. Mechanical properties of the collagen/chitosan sponge were significantly enhanced by EDC-mediated crosslinking. The potential of the sponge as a scaffold for tissue engineering was investigated using a Chinese hamster ovary cell (CHO-K1) line.     

The degradation of lectins,phaseolin and trypsin inhibitors during germination of white kidney beans,Phaseolus vulgaris L.

White kidney beans (Phaseolus vulgaris), cv Processor, contain a relatively high content of phaseolin (storage protein), lectins and a special group of glycoproteins as well as a considerable amount of protein-type trypsin inhibitors. Protein digestion of raw Processor beans in monogastrics, for example pigs, is disturbed by poorly digested, phaseolin lectins, which can bind to carbohydrates in brush border membranes of the small intestinal epithelium, and trypsin inhibitors. The effect of the germination of white kidney beans on lectins, phaseolin and trypsin inhibitors was studied in order to achieve a degradation of lectins, phaseolin and trypsin inhibitors and an increase ofin vitro enzymatic hydrolysis of the protein of bean flour. Therefore, whole bean extracts were examined throughout a germination period of up to seven days for their lectin and phaseolin pattern, lectin content, binding capacities of functional lectins towards brush border membranes and trypsin inhibitor content. In addition thein vitro enzymatic hydrolysis by pepsin and pancreatin of the protein from flours of (un)germinated white kidney beans was studied. SDS-PAGE demonstrated a degradation of E-lectins and a disappearance of L-lectins and phaseolin during germination. Results indicated a decrease of the lectin content by 85%, a loss of binding capacities of functional lectins towards brush border membranes by 91%, and a decrease of trypsin inhibitors by 76%, in bean flour after germination for seven days. A maximum inin vitro enzymatic hydrolysis of protein from bean flour was already established after germination for half a day.     

Phylogenetic identification of fungi isolated from the marine sponge Tethya aurantium and identification of their secondary metabolites

Fungi associated with the marine sponge Tethya aurantium were isolated and identified by morphological criteria and phylogenetic analyses based on internal transcribed spacer (ITS) regions. They were evaluated with regard to their secondary metabolite profiles. Among the 81 isolates which were characterized, members of 21 genera were identified. Some genera like Acremonium, Aspergillus, Fusarium, Penicillium, Phoma, and Trichoderma are quite common, but we also isolated strains belonging to genera like Botryosphaeria, Epicoccum, Parasphaeosphaeria, and Tritirachium which have rarely been reported from sponges. Members affiliated to the genera Bartalinia and Volutella as well as to a presumably new Phoma species were first isolated from a sponge in this study. On the basis of their classification, strains were selected for analysis of their ability to produce natural products. In addition to a number of known compounds, several new natural products were identified. The scopularides and sorbifuranones have been described elsewhere. We have isolated four additional substances which have not been described so far. The new metabolite cillifuranone (1) was isolated from Penicillium chrysogenum strain LF066. The structure of cillifuranone (1) was elucidated based on 1D and 2D NMR analysis and turned out to be a previously postulated intermediate in sorbifuranone biosynthesis. Only minor antibiotic bioactivities of this compound were found so far.     

Effects of Chitin and Sepia Ink Hybrid Hemostatic Sponge on the Blood Parameters of Mice

Chitin and sepia ink hybrid hemostatic sponge (CTSH sponge), a new biomedical material, was extensively studied for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CTSH sponge in the blood system are lacking. This experiment aimed to examine whether CTSH sponge has negative effect on blood systems of mice, which were treated with a dosage of CTSH sponge (135 mg/kg) through a laparotomy. CTSH sponge was implanted into the abdominal subcutaneous and a laparotomy was used for blood sampling from abdominal aortic. Several kinds of blood parameters were detected at different time points, which were reflected by coagulation parameters including thrombin time (TT), prothrombin time (PT), activated partial thromboplatin time (APTT), fibrinogen (FIB) and platelet factor 4 (PF4); anticoagulation parameter including antithrombin III (AT-III); fibrinolytic parameters including plasminogen (PLG), fibrin degradation product (FDP) and D-dimer; hemorheology parameters including blood viscosity (BV) and plasma viscosity (PV). Results showed that CTSH sponge has no significant effect on the blood parameters of mice. The data suggested that CTSH sponge can be applied in the field of biomedical materials and has potential possibility to be developed into clinical drugs of hemostatic agents.     

Unveiling the Chemical Diversity of the Deep-Sea Sponge Characella pachastrelloides

Sponges are at the forefront of marine natural product research. In the deep sea, extreme conditions have driven secondary metabolite pathway evolution such that we might expect deep-sea sponges to yield a broad range of unique natural products. Here, we investigate the chemodiversity of a deep-sea tetractinellid sponge, Characella pachastrelloides, collected from ~800 m depth in Irish waters. First, we analyzed the MS/MS data obtained from fractions of this sponge on the GNPS public online platform to guide our exploration of its chemodiversity. Novel glycolipopeptides named characellides were previously isolated from the sponge and herein cyanocobalamin, a manufactured form of vitamin B₁₂, not previously found in nature, was isolated in a large amount. We also identified several poecillastrins from the molecular network, a class of polyketide known to exhibit cytotoxicity. Light sensitivity prevented the isolation and characterization of these polyketides, but their presence was confirmed by characteristic NMR and MS signals. Finally, we isolated the new betaine 6-methylhercynine, which contains a unique methylation at C-2 of the imidazole ring. This compound showed potent cytotoxicity towards against HeLa (cervical cancer) cells.     

Bioactive Hydantoin Alkaloids from the Red Sea Marine Sponge Hemimycale arabica

In the course of our continuing efforts to identify bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Hemimycale arabica. The antimicrobial fraction of an organic extract of the sponge afforded two new hydantoin alkaloids, hemimycalins A and B (2 and 3), together with the previously reported compound (Z)-5-(4-hydroxybenzylidene)imidazolidine-2,4-dione (1). The structures of the compounds were determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determinations. Hemimycalins A (2) and B (3) represent the first examples of the natural N-alkylated hydantoins from the sponge Hemimycale arabica. Compounds 1–3 displayed variable antimicrobial activities against E. coli, S. aureus, and C. albicans. In addition, compound 1 displayed moderate antiproliferative activity against the human cervical carcinoma (HeLa) cell line. These findings provide further insight into the chemical diversity as well as the biological activity of this class of compounds.     

Functional Recombinants Designed from a Fetuin/Asialofetuin-Specific Marine Algal Lectin,Rhodobindin

Plant lectins have attracted much attention for biomedical applications including targeted drug delivery system and therapy against tumors and microbial infections. The main problem of using lectins as a biomedical tool is a batch-to-batch variation in isoforms content. The production of lectins using recombination tools has the advantage of obtaining high amounts of proteins with more precise properties, but there are only a handful of functional recombinant lectins presently available. A fetuin/asialo-fetuin specific lectin, Rhodobindin, has unique tandem repeats structure which makes it useful in exploiting for recombinant lectin. We developed three functional recombinant lectins using E. coli expression system: one from full cDNA sequence and two from fragmentary sequences of Rhodobindin. Hemagglutinating activity and solubility of the recombinant lectins were highest at OD 0.7 cell concentration at 20 °C. The optimized process developed in this study was suitable for the quality-controlled production of high amounts of soluble recombinant lectins.     

Stereochemical Determination of Fistularins Isolated from the Marine Sponge Ecionemia acervus and Their Regulatory Effect on Intestinal Inflammation

By activity-guided fractionation based on inhibition of nitric oxide (NO) and prostaglandin E2 (PGE₂), six fistularin compounds (1–6) were isolated from the marine sponge Ecionemia acervus (order Astrophorida). Based on stereochemical structure determination using Mosher’s method, fistularin-3 was assigned as a new stereoisomer. On the basis of the stereochemistry of fistularin-3, the stereochemical homogeneity of all six compounds was established by comparing carbon and proton chemical shifts. For fistularin-1 (1) and -2 (2), quantum calculations were performed to confirm their stereochemistry. In a co-culture system of human epithelial Caco-2 cells and THP-1 macrophages, all six isolated compounds showed potent anti-inflammatory activities. These bioactive fistularins inhibited the production of NO, PGE₂, TNF-α, IL-1β, and IL-6 induced by lipopolysaccharide and interferon gamma. Inducible NO synthase and cyclooxygenase-2 expression and MAPK phosphorylation were downregulated in response to the inhibition of NF-κB nuclear translocation. Among the compounds tested, fistularin-1 (1) and 19-deoxyfistularin-3 (4) showed the highest activity. These findings suggest the potential use of the marine sponge E. acervus and its metabolites as pharmaceuticals for the treatment of inflammation-related diseases including inflammatory bowel disease.     

Man-Specific,GalNAc/T/Tn-Specific and Neu5Ac-Specific Seaweed Lectins as Glycan Probes for the SARS-CoV-2 (COVID-19) Coronavirus

Seaweed lectins, especially high-mannose-specific lectins from red algae, have been identified as potential antiviral agents that are capable of blocking the replication of various enveloped viruses like influenza virus, herpes virus, and HIV-1 in vitro. Their antiviral activity depends on the recognition of glycoprotein receptors on the surface of sensitive host cells—in particular, hemagglutinin for influenza virus or gp120 for HIV-1, which in turn triggers fusion events, allowing the entry of the viral genome into the cells and its subsequent replication. The diversity of glycans present on the S-glycoproteins forming the spikes covering the SARS-CoV-2 envelope, essentially complex type N-glycans and high-mannose type N-glycans, suggests that high-mannose-specific seaweed lectins are particularly well adapted as glycan probes for coronaviruses. This review presents a detailed study of the carbohydrate-binding specificity of high-mannose-specific seaweed lectins, demonstrating their potential to be used as specific glycan probes for coronaviruses, as well as the biomedical interest for both the detection and immobilization of SARS-CoV-2 to avoid shedding of the virus into the environment. The use of these seaweed lectins as replication blockers for SARS-CoV-2 is also discussed.     

Sponges and Their Symbionts as a Source of Valuable Compounds in Cosmeceutical Field

In the last decades, the marine environment was discovered as a huge reservoir of novel bioactive compounds, useful for medicinal treatments improving human health and well-being. Among several marine organisms exhibiting biotechnological potential, sponges were highlighted as one of the most interesting phyla according to a wide literature describing new molecules every year. Not surprisingly, the first marine drugs approved for medical purposes were isolated from a marine sponge and are now used as anti-cancer and anti-viral agents. In most cases, experimental evidence reported that very often associated and/or symbiotic communities produced these bioactive compounds for a mutual benefit. Nowadays, beauty treatments are formulated taking advantage of the beneficial properties exerted by marine novel compounds. In fact, several biological activities suitable for cosmetic treatments were recorded, such as anti-oxidant, anti-aging, skin whitening, and emulsifying activities, among others. Here, we collected and discussed several scientific contributions reporting the cosmeceutical potential of marine sponge symbionts, which were exclusively represented by fungi and bacteria. Bioactive compounds specifically indicated as products of the sponge metabolism were also included. However, the origin of sponge metabolites is dubious, and the role of the associated biota cannot be excluded, considering that the isolation of symbionts represents a hard challenge due to their uncultivable features.     

Marine Demospongiae: A Challenging Treasure of Bioactive Compounds

In the last decades, it has been demonstrated that marine organisms are a substantial source of bioactive compounds with possible biotechnological applications. Marine sponges, in particular those belonging to the class of Demospongiae, have been considered among the most interesting invertebrates for their biotechnological potential. In this review, particular attention is devoted to natural compounds/extracts isolated from Demospongiae and their associated microorganisms with important biological activities for pharmacological applications such as antiviral, anticancer, antifouling, antimicrobial, antiplasmodial, antifungal and antioxidant. The data here presented show that this class of sponges is an exciting source of compounds, which are worth developing into new drugs, such as avarol, a hydroquinone isolated from the marine sponge Disidea avara, which is used as an antitumor, antimicrobial and antiviral drug.     

Fabrication of silk fibroin based three dimensional scaffolds for tissue engineering

Herein we report successful synthesis of silk fibroin (SF) three dimensional scaffolds (SF 3D-scaffold) from SF sponge and SF nanofibers. Both the nanofibers and sponge were prepared from Bombyx mori fibroin. The SF 3D-scaffold was prepared by electrospinning the fibroin nanofibers over the sponge. Surface morphology was determined by scanning electron microscopy (SEM), while nanofiber diameter and pore size were measured using imageJ software. Effect of spinning time on the pore size and cell adhesion was determined. Average diameter of the SF nanofibers was measured to be 320 nm and pore size was found to reduce with increasing spinning time, such that, for 1 h spinning time pore size was 231 µm and the same for 3.5 h was 4.1 µm. However, the number of pores increased with spinning time. The results confirmed adhesion of MC3T3-E1 cells on the SF sponge, SF nanofibers and SF three dimensional scaffolds. Higher cell adhesion was found on the three dimensional scaffold in comparison to the nanofibers and sponge, possibly due to highly porous structure with very small and numerous pores in the resultant composite; hence more cell adhesion sites. The cell adhesion result confirmed biocompatibility of the SF 3D-scaffold and hence its suitability for applications in tissue engineering.     

A New Micromonospora Strain with Antibiotic Activity Isolated from the Microbiome of a Mid-Atlantic Deep-Sea Sponge

To tackle the growing problem of antibiotic resistance, it is essential to identify new bioactive compounds that are effective against resistant microbes and safe to use. Natural products and their derivatives are, and will continue to be, an important source of these molecules. Sea sponges harbour a diverse microbiome that co-exists with the sponge, and these bacterial communities produce a rich array of bioactive metabolites for protection and resource competition. For these reasons, the sponge microbiota constitutes a potential source of clinically relevant natural products. To date, efforts in bioprospecting for these compounds have focused predominantly on sponge specimens isolated from shallow water, with much still to be learned about samples from the deep sea. Here we report the isolation of a new Micromonospora strain, designated 28ISP2-46^T, recovered from the microbiome of a mid-Atlantic deep-sea sponge. Whole-genome sequencing reveals the capacity of this bacterium to produce a diverse array of natural products, including kosinostatin and isoquinocycline B, which exhibit both antibiotic and antitumour properties. Both compounds were isolated from 28ISP2-46^T fermentation broths and were found to be effective against a plethora of multidrug-resistant clinical isolates. This study suggests that the marine production of isoquinocyclines may be more widespread than previously supposed and demonstrates the value of targeting the deep-sea sponge microbiome as a source of novel microbial life with exploitable biosynthetic potential.     

Production of Lectins from Marine Algae: Current Status,Challenges, and Opportunities for Non-Destructive Extraction

Marine algae are an excellent source of novel lectins. The isolation of lectins from marine algae expands the diversity in structure and carbohydrate specificities of lectins isolated from other sources. Marine algal lectins have been reported to have antiviral, antitumor, and antibacterial activity. Lectins are typically isolated from marine algae by grinding the algal tissue with liquid nitrogen and extracting with buffer and alcohol. While this method produces higher yields, it may not be sustainable for large-scale production, because a large amount of biomass is required to produce a minute amount of compound, and a significant amount of waste is generated during the extraction process. Therefore, non-destructive extraction using algal culture water could be used to ensure a continuous supply of lectins without exclusively disrupting the marine algae. This review discusses the traditional and recent advancements in algal lectin extraction methods over the last decade, as well as the steps required for large-scale production. The challenges and prospects of various extraction methods (destructive and non-destructive) are also discussed.     

Relative and Absolute Stereochemistry of Diacarperoxides: Antimalarial Norditerpene Endoperoxides from Marine Sponge Diacarnus megaspinorhabdosa

Five new norditerpene endoperoxides, named diacarperoxides H–L (1–5), and a new norditerpene diol, called diacardiol B (6), were isolated from the South China Sea sponge, Diacarnus megaspinorhabdosa. Their structures, including conformations and absolute configurations, were determined by using spectroscopic analyses, computational approaches and chemical degradation. Diacarperoxides H–J (1–3) showed some interesting stereochemical issues, as well as antimalarial activity.     

Effects of Short-term Heating on Total Polyphenols,Anthocyanins, Antioxidant Activity and Lectins of Different Parts of Dwarf Elder (Sambucus ebulus L.)

Dwarf elder (Sambucus ebulus L.) berries are rich in health-promoting phytochemicals such as polyphenols and anthocyanins, and display a significant antioxidant activity. They are also rich in two lectins (ebulin f and SELfd) that share amino acid sequence homology with the elderberry allergen Sam n1 present in Sambucus nigra pollen and fruits. Ebulin f displays toxicity by oral ingestion. This study was aimed at eliminating the toxicity of these lectins whilst having little or no effect on the antioxidant properties of dwarf elder berries. We thus investigated the potential effects of incubation in a boiling water bath of extracts from several parts of the plant on total polyphenol content, antioxidant activity, total anthocyanins, cyanidin-3-glycoside content, and the sensitivity of purified dwarf elder fruit lectins to a simulated gastric fluid. The study shows that five minutes of said heat treatment fully sensitized both lectins to pepsin digestion, whilst minimally reducing phenol and antioxidant as well as free radical scavenging activities to below 13 %. It proved possible to eliminate the potential risks derived from the presence of lectins in dwarf elder juices without any significant reduction in the content of the antioxidant compounds. Dwarf elder berries may thus be a valuable nutritional source.