Exploring the Exopolysaccharide Production Potential of Bacterial Strains Isolated from Tunisian Blue Crab Microbiota.

The blue crab (BC) is considered an invasive species colonizing Tunisian coasts since 2014. This work aims to explore its associated bacteria potential to produce anionic exopolysaccharides (EPSs) in order to open up new ways of valorization. In this study, different BC samples were collected from the coastal area of Sfax, Tunisia.

Multi-step semi-synthesis, structural characterization and growth factor interaction study of regiochemically sulfated diabolican polysaccharides.

Diabolican is an exopolysaccharide (EPS) produced by Vibrio diabolicus HE800, a mesophilic bacterium firstly isolated from a deep-sea hydrothermal field. Its glycosaminoglycan (GAG)-like structure, consisting of a tetrasaccharide repeating unit composed of two aminosugars (N-acetyl-glucosamine and N-acetyl-galactosamine) and two glucuronic acid units, suggested to subject it to regioselective sulfation processes, in order to obtain some sulfated derivatives potentially acting as GAG mimics. To this aim, a multi-step semi-synthetic approach, relying upon tailored sequence of regioselective protection, sulfation and deprotection steps, was employed in this work.

Glycosaminoglycan-mimetic infernan grafted with poly(N-isopropylacrylamide): Toward a thermosensitive polysaccharide.

Glycosaminoglycans (GAGs) are essential constituents of the cell surface and extracellular matrix, where they are involved in several cellular processes through their interactions with various proteins. For successful tissue regeneration, developing an appropriate matrix supporting biological activities of cells in a similar manner than GAGs remains still challenging. In this context, this study aims to design a thermosensitive polysaccharide that could further be used as hydrogel for tissue engineering applications.

Marine versus Non-Marine Bacterial Exopolysaccharides and Their Skincare Applications.

Bacteria are well-known to synthesize high molecular weight polysaccharides excreted in extracellular domain, which constitute their protective microenvironment. Several bacterial exopolysaccharides (EPS) are commercially available for skincare applications in cosmetic products due to their unique structural features, conferring valuable biological and/or textural properties. This review aims to give an overview of bacterial EPS, an important group of macromolecules used in cosmetics as actives and functional ingredients.

Production and composition of extracellular polymeric substances by a unicellular strain and natural colonies of Microcystis: Impact of salinity and nutrient stress.

The transfer of toxic cyanobacterial Microcystis blooms from freshwater to estuaries constitutes a serious environmental problem worldwide that is expected to expand in scale and intensity with anthropogenic and climate change. The formation and maintenance of Microcystis in colonial form is conditioned to the presence of extracellular polymeric substances (EPS). In this study, we attempted to better understand how the mucilaginous colonial form of Microcystis evolves under environmental stress conditions.

Low-molecular weight sulfated marine polysaccharides: Promising molecules to prevent neurodegeneration in mucopolysaccharidosis IIIA?

Mucopolysaccharidosis IIIA is a hereditary disease caused by mutations in the sulfamidase enzyme that participates in catabolism of heparan sulfate (HS), leading to HS fragment accumulation and multisystemic failure. No cure exists and death occurs around the second decade of life. Two low molecular weight highly sulfated compounds derived from marine diabolican and infernan exopolysaccharides (A5_3 and A5_4, respectively) with heparanase inhibiting properties were tested in a MPSIIIA cell line model, resulting in limited degradation of intracellular HS.

Mechanical relaxations of hydrogels governed by their physical or chemical crosslinks.

In the field of tissue engineering, in order to restore tissue functionality hydrogels that closely mimic biological and mechanical properties of the extracellular matrix are intensely developed. Mechanical properties including relaxation of the surrounding microenvironment regulate essential cellular processes. However, the mechanical properties of engineered hydrogels are particularly complex since they involve not only a nonlinear elastic behavior but also time-dependent responses.

Interactions between infernan and calcium: From the molecular level to the mechanical properties of microgels.

With the increasing need for hydrogels with tunable properties for specific biomedical applications, a complete understanding of the structure-function relationship of polymers used for hydrogel development remains crucial for their optimal use. In the present study, by combining experimental and theoretical approaches, the structure-function relationship of a bacterial exopolysaccharide, infernan, displaying both glycosaminoglycan-mimetic and gelling properties, was investigated at molecular and microscopic levels. Atomic force microscopy (AFM) experiments and molecular dynamics simulations were applied to determine the persistence length of individual infernan chains before studying their association induced by calcium.

Influence of the Carbon and Nitrogen Sources on Diabolican Production by the Marine Strain CNCM I-1629.

Recent advances in glycobiotechnology show that bacterial exopolysaccharides (EPS) presenting glycosaminoglycan (GAG)-like properties can provide a valuable source of bio-active macromolecules for industrial applications. The HE800 EPS, named diabolican, is a marine-derived anionic high-molecular-weight polysaccharide produced by CNCM I-1629 which displays original structural features close to those of hyaluronic acid. We investigated the impact of carbon and nitrogen substrates on both growth and diabolican production.

Microgels based on Infernan, a glycosaminoglycan-mimetic bacterial exopolysaccharide, as BMP-2 delivery systems.

Bone Morphogenetic Protein (BMP-2) is an osteoinductive growth factor clinically used for bone regeneration. Tuneable sustained strategies for BMP-2 delivery are intensely developed to avoid severe complications related to supraphysiological doses applied. To address this issue, we investigated the ability of the bacterial exopolysaccharide (EPS) called Infernan produced by the deep-sea hydrothermal vent bacterium Alteromonas infernus, exhibiting both glycosaminoglycan-mimetic and physical gelling properties, to efficiently bind and release the bioactive BMP-2.

Glycosaminoglycan-like sulfated polysaccharides from Vibrio diabolicus bacterium: Semi-synthesis and characterization.

Sulfated glycosaminoglycan (GAG) analogues derived from plant, algae or microbial sourced polysaccharides are highly interesting in order to gain bioactivities similar to sulfated GAGs but without risks and concerns derived from their typical animal sources. Since the exopolysaccharide (EPS) produced by the bacterium Vibrio diabolicus HE800 strain from deep-sea hydrothermal vents is known to have a GAG-like structure with a linear backbone composed of unsulfated aminosugar and uronic acid monomers, its structural modification through four different semi-synthetic sulfation strategies has been performed. A detailed structural characterization of the six obtained polysaccharides revealed that three different sulfation patterns (per-O-sulfation, a single N-sulfation and a selective primary hydroxyls sulfation) were achieved, with molecular weights ranging from 5 to 40 kDa.

Antiproliferative Properties of Scandium Exopolysaccharide Complexes on Several Cancer Cell Lines.

Antimetastatic properties on both murine and human osteosarcoma cell lines (POS-1 and KHOS) have been evidenced using exopolysaccharide (EPS) derivatives, produced by bacterium. These derivatives had no significant effect on the cell cycle neither a pro-apoptotic effect on osteosarcoma cells. Based on this observation, these EPSs could be employed as new drug delivery systems for therapeutic uses.

Marine Exopolysaccharide Complexed With Scandium Aimed as Theranostic Agents.

(1) Background: Exopolysaccharide (EPS) derivatives, produced by bacterium, showed anti-metastatic properties. They may represent a new class of ligands to be combined with theranostic radionuclides, such as Sc/Sc. The goal of this work was to investigate the feasibility of such coupling.

Bacteria enhance the production of extracellular polymeric substances by the green dinoflagellate Lepidodinium chlorophorum.

High biomasses of the marine dinoflagellate Lepidodinium chlorophorum cause green seawater discolorations along Southern Brittany (NE Atlantic, France). The viscosity associated to these phenomena has been related to problems in oyster cultivation. The harmful effect of L.

Characterization of New Oligosaccharides Obtained by An Enzymatic Cleavage of the Exopolysaccharide Produced by the Deep-Sea Bacterium Using its Cell Extract.

Bacteria from deep-sea hydrothermal vents constitute an attractive source of bioactive molecules. In particular, exopolysaccharides (EPS) produced by these bacteria become a renewable source of both biocompatible and biodegradable molecules. The low molecular weight (LMW) derivatives of the GY785 EPS produced by the deep-sea hydrothermal vent strain have previously displayed some biological properties, similar to those of glycosaminoglycans (GAG), explored in cancer and tissue engineering.

Deep-sea Hydrothermal Vent Bacteria as a Source of Glycosaminoglycan-Mimetic Exopolysaccharides.

Bacteria have developed a unique strategy to survive in extreme environmental conditions through the synthesis of an extracellular polymeric matrix conferring upon the cells a protective microenvironment. The main structural component of this complex network constitutes high-molecular weight hydrophilic macromolecules, namely exopolysaccharides (EPS). EPS composition with the presence of particular chemical features may closely be related to the specific conditions in which bacteria evolve.

Marine Polysaccharide-Collagen Coatings on Ti6Al4V Alloy Formed by Self-Assembly.

Polysaccharides of marine origin are gaining interest as biomaterial components. Bacteria derived from deep-sea hydrothermal vents can produce sulfated exopolysaccharides (EPS), which can influence cell behavior. The use of such polysaccharides as components of organic, collagen fibril-based coatings on biomaterial surfaces remains unexplored.

Microcarriers Based on Glycosaminoglycan-Like Marine Exopolysaccharide for TGF-β1 Long-Term Protection.

Articular cartilage is an avascular, non-innervated connective tissue with limited ability to regenerate. Articular degenerative processes arising from trauma, inflammation or due to aging are thus irreversible and may induce the loss of the joint function. To repair cartilaginous defects, tissue engineering approaches are under intense development.

Investigation of interactions between the marine GY785 exopolysaccharide and transforming growth factor-β1 by atomic force microscopy.

Sulfated polysaccharides, such as glycosaminoglycans (GAG) regulate various biological activities through their interactions with growth factors. Investigating these interactions becomes the key to understand the structure-function relationship of GAG. Highly sulfated derivatives prepared from the marine GY785 exopolysaccharide (EPS) produced by the deep-sea hydrothermal vent bacterium Alteromonas infernus have previously shown to stimulate the chondrogenic differentiation of mesenchymal stem cells in the presence of Transforming Growth Factor-β1 (TGF-β1).

Enzymatic depolymerization of the GY785 exopolysaccharide produced by the deep-sea hydrothermal bacterium Alteromonas infernus: Structural study and enzyme activity assessment.

Polysaccharides have attracted much attention due to their interesting physico-chemical and also biological properties that are explored in food, cosmetic and pharmaceutical industries. GY785 exopolysaccharide (EPS) presenting an unusual structure is secreted by the deep-sea hydrothermal bacterium, Alteromonas infernus. Low-molecular weight (LMW) derivatives obtained by chemical depolymerization of the native high molecular weight (HMW) EPS were previously shown to exhibit biological properties similar to glycosaminoglycans (GAG).

Bioprospecting for Exopolysaccharides from Deep-Sea Hydrothermal Vent Bacteria: Relationship between Bacterial Diversity and Chemical Diversity.

Many bacteria biosynthesize structurally diverse exopolysaccharides (EPS) and excrete them into their surrounding environment. The EPS functional features have found many applications in industries such as cosmetics and pharmaceutics. In particular, some EPS produced by marine bacteria are composed of uronic acids, neutral sugars, and -acetylhexosamines, and may also bear some functional sulfate groups.

Purification of the exopolysaccharide produced by Alteromonas infernus: identification of endotoxins and effective process to remove them.

Alteromonas infernus bacterium isolated from deep-sea hydrothermal vents can produce by fermentation a high molecular weight exopolysaccharide (EPS) called GY785. This EPS described as a new source of glycosaminoglycan-like molecule presents a great potential for pharmaceutical and biotechnological applications. However, this unusual EPS is secreted by a Gram-negative bacterium and can be therefore contaminated by endotoxins, in particular the lipopolysaccharides (LPS).

Anti-Metastatic Properties of a Marine Bacterial Exopolysaccharide-Based Derivative Designed to Mimic Glycosaminoglycans.

Osteosarcoma is the most frequent malignant primary bone tumor characterized by a high potency to form lung metastases. In this study, the effect of three oversulfated low molecular weight marine bacterial exopolysaccharides (OS-EPS) with different molecular weights (4, 8 and 15 kDa) were first evaluated in vitro on human and murine osteosarcoma cell lines. Different biological activities were studied: cell proliferation, cell adhesion and migration, matrix metalloproteinase expression.

Assembly of HE800 exopolysaccharide produced by a deep-sea hydrothermal bacterium into microgels for protein delivery applications.

Assembly of biopolymers into microgels is an elegant strategy for bioencapsulation with various potential biomedical applications. Such biocompatible and biodegradable microassemblies are developed not only to protect the encapsulated molecule but also to ensure its sustained local delivery. The present study describes the fabrication of microassemblies from a marine HE800 exopolysaccharide (EPS), which displays a glycosaminoglycan (GAG)-like structure and biological properties.