Endogenous enzymatic antioxidant status of whiteleg shrimp (Litopenaeus vannamei) following exposure to sublethal concentrations of silver nanoparticles.

Immunotoxicity of silver nanoparticles (AgNPs) to whiteleg shrimp (Litopenaeus vannamei) was assessed using redox-status orchestrating enzymes. To this end, the shrimp was exposed to sublethal AgNPs concentrations (0 % LC50: control; 25 % LC50: 0.97 mg/L; 50 % LC50: 1.95 mg/L; 75 % LC50: 2.92 mg/L). During the experiment, the behavior of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx) was monitored, besides total antioxidant capacity (TAC) and malondialdehyde (MDA). The hepatopancreas SOD activity reduced about 63 %-76 % at.%50 LC50 and %75 LC50 AgNPs treatments, and CAT decreased in both tissues at 50 % LC50 AgNPs. TAC exhibited a U-form response in the hepatopancreas organ against stress caused by AgNPs, and hepatopancreas MDA displayed a time-dependent increase. Taken together, AgNPs triggered severe immunotoxicity through suppression of CAT, SOD, and TAC in the hepatopancreas tissue.

The activation of NF-κB and MAPKs signaling pathways of RAW264.7 murine macrophages and natural killer cells by fucoidan from Nizamuddinia zanardinii.

Polysaccharides from Nizamuddinia zanardinii were extracted using water at elevated temperature and fractionated by a DEAE Sepharose FF column yielding four fractions (F1-F4). Crude and fractions were composed of neutral sugars (50.8-57.4%), proteins (10.8-18.1%), sulfates (7.5-17.3%) and uronic acids (3.5-7.7%). Various levels of galactose (13.4-44.4%), fucose (34.1-40.1%), mannose (14.1-33.2%) and xylose (7.4-15.2%) formed the building blocks of the polysaccharide structures. The weight average molecular weights (Mw) of polysaccharides varied between 40.3 and 1254.4 × 103 g/mol. F3 polysaccharide was the most active fraction stimulating RAW264.7 murine macrophage cells to secrete NO, TNF-α, IL-1ß and IL-6, and activating NK cells to release TNF-α, INF-γ, granzyme-B, perforin, NKG2D and FasL through NF-κB and MAPKs signaling pathways. Highly-branched F3 polysaccharide mainly consisted of (1 â†’ 2)-Fucp, (1 â†’ 2,3)-Manp, (1 â†’ 3)-Galp, (1 â†’ 2)-Manp, (1 â†’ 3)-Manp, (1 â†’ 2,3,4)-Manp and (1 â†’ 2,3,6)-Manp residues with great amount of (→1)-Fucp and (→1)-Xylp. Sulfates substituted at C-2 of fucose and galactose residues. Overall, fucoidan from N. zanardinii showed immense potency in boosting immune system through macrophages and NK cells activations and therefore suitable for further exploration in immune-mediated biomedical applications.

Purification, structural analysis and mechanism of murine macrophage cell activation by sulfated polysaccharides from Cystoseira indica.

Sulfated polysaccharides were isolated and purified from the water extract of Cystoseira indica using DEAE Sepharose Fast Flow column to evaluate their structure and macrophage stimulating capacity. Crude and fractionated polysaccharides, CIF1 and CIF2, were mostly composed of neutral sugars (73.1%-78.6%) with relatively lower amounts of acidic sugars (1.3%-9.0%) and sulfate esters (6.9%-9.7%). The polymer chains of polysaccharides were mainly built of different levels of glucose (2.1%-30.8%), fucose (17.2%-24.4%), mannose (17.8%-20.6%) and galactose (16.7%-17.3%). The weight average molecular weight (Mw) of polysaccharides varied between 573.1 × 103 g/mol to 1146.6 × 103 g/mol. The CIF2 polysaccharide, as the most immunostimulating polysaccharide, remarkably induced the release of nitric oxide and inflammatory cytokines including TNF-α, IL-1ß, IL-6 and IL-10 from RAW264.7 murine macrophage cells through NF-κB and PAMKs transduction signaling pathways via cell surface TLR4. The interconnections of sugars in CIF2 polysaccharide were complex with (1→3)-fucopyranose, (1→2,3,4)-glucopyranose, (→1)-galactopyranose, (→1)-xylopyranose, (1→2)-rhamnopyranose and (1→2,3)-mannopyranose units being the most predominant residues.