Antioxidant properties of low-molecular-weight Ulva prolifera polysaccharides against H₂O₂-induced oxidative damage in BRL 3A cells and zebrafish.

Distribution of Ulva macroalgae before and after the outbreak of the Yellow Sea green tide in aquaculture ponds and rivers nearshore Jiangsu, China

BACKGROUND/OBJECTIVESThis study was performed to investigate the in vitro antioxidant and cytoprotective effects of fermented sesame sauce (FSeS) against hydrogen peroxide (H2O2)-induced oxidative damage in renal proximal tubule LLC-PK1 cells.MATERIALS/METHODS1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (•OH), and H2O2 scavenging assay was used to evaluate the in vitro antioxidant activity of FSeS. To investigate the cytoprotective effect of FSeS against H2O2-induced oxidative damage in LLC-PK1 cells, the cellular levels of reactive oxygen species (ROS), lipid peroxidation, and endogenous antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px) were measured.RESULTSThe ability of FSeS to scavenge DPPH, •OH and H2O2 was greater than that of FSS and AHSS. FSeS also significantly inhibited H2O2-induced (500 µM) oxidative damage in the LLC-PK1 cells compared to FSS and AHSS (P < 0.05). Following treatment with 100 µg/mL of FSeS and FSS to prevent H2O2-induced oxidation, cell viability increased from 56.7% (control) to 83.7% and 75.6%, respectively. However, AHSS was not able to reduce H2O2-induced cell damage (viability of the AHSS-treated cells was 54.6%). FSeS more effectively suppressed H2O2-induced ROS generation and lipid peroxidation compared to FSS and AHSS (P < 0.05). Compared to the other sauces, FSeS also significantly increased cellular CAT, SOD, and GSH-px activities and mRNA expression (P < 0.05).CONCULUSIONSThese results from the present study suggest that FSeS is an effective radical scavenger and protects against H2O2-induced oxidative damage in LLC-PK1 cells by reducing ROS levels, inhibiting lipid peroxidation, and stimulating antioxidant enzyme activity.

Lichen pectin-containing polysaccharide from Xanthoria elegans and its ability to effectively protect LX-2 cells from H2O2-induced oxidative damage

Phycoremediation of coastal waters contaminated with bisphenol A by green tidal algae Ulva prolifera

Bacteria associated with Ulva prolifera: a vital role in green tide formation and migration

Removal of phenanthrene from coastal waters by green tide algae Ulva prolifera

The green tide in the Yellow Sea which has been erupting continuously for 13 years, has brought a huge disaster to the ecosystem. There are four Ulva species from the early stage of green tide in the Yellow Sea usually: Ulva prolifera, Ulva compressa, Ulva flexuosa and Ulva linza. With the passage of time, the green tide floating to Qingdao mainly consists of Ulva prolifera. Molecular biological identification of species during the outbreak of green tide in the Yellow Sea has always been a focus of surveillance, but the ‘ITS-5S’ test system we have been using for a long time is not perfect. Through analyzing the mitochondrial genome of species published by our laboratory and combining with the other mitochondrial genome data, we find that the rps2-trnL gene spacer sequences can accurately distinguish the Ulva species of the green tide. After gene amplification and the construction of Maximum Likelihood phylogenetic tree, we find that the rps2-trnL gene spacer sequence is completely suitable for the barcode sequence of common Ulva species. This discovery could save researchers a lot of money and time, also, provide basic data for future green tide prevention and control.

Ulva prolifera plays an important part in most green tides around the world. To explore its possible use, the immunostimulatory effect of orally administered U. prolifera polysaccharides in white shrimp, Litopenaeus vannamei, was investigated in this study. Shrimp were divided into four groups: a group fed with the basal diet as the control group (control), and three treatment groups fed respectively with a basal diet supplemented with polysaccharides of cold water extract (PC), polysaccharides of hot water extract (PH), and the filtered residue after the extraction of polysaccharides (R). The highest final weight was found in the group PC (9.31 ± 0.54 g), followed by R (9.11 ± 0.63 g), PH (8.94 ± 0.61 g), and the control group (8.65 ± 0.53 g); the final weight of shrimp in group PC and group R was significantly greater than that in the control group (P 0.05); however, they were significantly lower than that in the control group (P < 0.05) while they were significantly higher than that in group PC (P < 0.05). The highest immune protective rate was found in group PC, followed by group R and PH. There were no significances in immune protective rate between group PH and R; however, they were significantly lower than that in group PC. These results suggest that dietary U. prolifera polysaccharides can promote shrimp growth and enhance non-specific immune and disease resistance enhancement against V. parahaemolyticus in L. vannamei. The findings from this present study will help to promote the application of U. prolifera in aquaculture.

Effects of low molecular weight polysaccharides from Ulva prolifera on the tolerance of Triticum aestivum to osmotic stress

In our in vitro study, we analyzed the effects of incubation of J774A.1 macrophages with reduced glutathione (GSH) and quercetin on the extent of cellular cholesterol efflux by high-density lipoprotein (HDL) or apolipoprotein A1 (apoA1). This combination was the most potent one among other exogenous and endogenous antioxidant combinations, since it significantly increased the extent of HDL-mediated cholesterol efflux from macrophages by 47% versus control cells, whereas quercetin (20 μM) or GSH (200 μM) alone increased it by only 37% or 17%, respectively. Similarly, apoA1-mediated cholesterol efflux was increased by 11% or 22% in quercetin or quercetin + GSH-treated cells, respectively, versus control cells. These stimulatory effects were noted only after 20 h of cell incubation. The combination of quercetin + GSH demonstrated high scavenging capacity of free radicals versus quercetin or GSH alone. In addition, quercetin + GSH significantly decreased macrophage oxidative stress as measured by the scavenging capacity of free radicals in the cells, the formation of reactive oxygen species, and the levels of cellular glutathione and lipid peroxides. There was no significant effect of quercetin + GSH on cellular HDL binding, on ATP-binding cassette A1 (ABCA1) activity, or on ABCG1 messenger RNA (mRNA) levels.In contrast, mRNA levels for ABCA1 and peroxisome proliferator-activated receptor alpha (PPARα) were both significantly increased by 89% and 93%, respectively, in quercetin + GSH-treated cells versus control cells. Quercetin alone increased the mRNA levels for ABCA1 or PPARα by 42% or 77%, respectively, whereas GSH alone increased it by 22% or 28%, respectively. Mass spectra analysis revealed that oxidized quercetin reacts with GSH to form a new adduct product. We thus conclude that the stimulatory effects of quercetin + GSH on apoA1- or HDL-mediated macrophage cholesterol efflux are related to the ability of GSH to preserve quercetin in its reduced form.

Green tides caused by Ulva prolifera occur annually in the Yellow Sea of China, and the massive amount of biomass decomposing during the demise stage of this green tide has deleterious ecological effects. Although microorganisms are considered key factors influencing algal bloom demise, an understanding of the microbial-algae interactions within the phycospheric microenvironment during this process is still lacking. Here, we focused on the variations in phycospheric microbial communities during the late stage of the green tide in three typically affected areas of the Yellow Sea via metagenomic sequencing analysis. In total, 16.9 million reads obtained from 18 metagenome samples were incorporated into the assembled contigs (13.4 Gbp). The phycosphere microbial community composition and diversity changed visibly during the demise of U. prolifera. The abundances of algae-lysing bacteria, Flavobacteriaceae at the family level and Alteromonas, Maribacter, and Vibrio at the genus level increased significantly in the phycosphere. In addition, the levels of glycoside hydrolases (GHs) and polysaccharide lyases (PLs) enzymes, which decompose U. prolifera polysaccharides in the phycosphere, were greater. Therefore, the degradation of algal polysaccharides can increase the efficiency of carbon metabolism pathways in the phycospheric microenvironment. Most of the genes detected in the phycosphere, especially norC, nrfA, and nasA, were associated with nitrogen metabolism pathways and showed dynamics related to the demise of the large amount of organic matter released by a green tide. Therefore, the demise of green tide algae may affect the potential carbon and nitrogen cycles of the phycospheric microenvironment by driving changes in the structure and diversity of microbial communities. Our research provides a novel perspective to better understand the ecological impact of U. prolifera during the green tide demise stage.

BackgroundThe enriched environment (EE) is a laboratory housing model that emerged from efforts to minimize the impact of environmental conditions on laboratory animals. Recently, we showed that EE promoted positive effects on behavior and cortisol levels in zebrafish submitted to the unpredictable chronic stress (UCS) protocol. Here, we expanded the characterization of the effects of UCS protocol by assessing parameters of oxidative status in the zebrafish brain and reveal that EE protects against the oxidative stress induced by chronic stress.MethodsZebrafish were exposed to EE (21 or 28 days) or standard housing conditions and subjected to the UCS protocol for seven days. Oxidative stress parameters (lipid peroxidation (TBARS), reactive oxygen species (ROS) levels, non-protein thiol (NPSH) and total thiol (SH) levels, superoxide dismutase (SOD) and catalase (CAT) activities were measured in brain homogenate.ResultsOur results revealed that UCS increased lipid peroxidation and ROS levels, while decreased NPSH levels and SOD activity, suggesting oxidative damage. EE for 28 days prevented all changes induced by the UCS protocol, and EE for 21 days prevented the alterations on NPSH levels, lipid peroxidation and ROS levels. Both EE for 21 or 28 days increased CAT activity.DiscussionOur findings reinforce the idea that EE exerts neuromodulatory effects in the zebrafish brain. EE promoted positive effects as it helped maintain the redox homeostasis, which may reduce the susceptibility to stress and its oxidative impact.

Moderate hyperhomocysteinemia is a risk factor for neurodegenerative diseases and complications during pregnancy. Increased homocysteine levels during pregnancy may elevate developmental risk on fetal brain structure and function. However, little is known about the mechanism of action of homocysteine on the degeneration of the fetal brain. Hence in this study, we examined the effects of maternal hyperhomocysteinemia on oxidative stress and apoptosis in brain tissues and investigated whether administration of melatonin to the mother would prevent homocysteine-induced oxidative cerebral damage in pups. Hyperhomocysteinemia was induced in female rats by administration of methionine at a dose of 1 g/kg body weight dissolved in drinking water during pregnancy. Some animals received methionine plus 10 mg/kg/day melatonin subcutaneously throughout pregnancy. After delivery, the level of lipid peroxidation (malondialdehyde + 4-hydroxyalkenals) was determined in different subfractions of pup brains. Furthermore, DNA fragmentation, levels of Bcl-2 protein and p53 mRNA expression were determined to evaluate apoptosis. Significant elevation was found in the levels of lipid peroxidation in subcellular fractions of the brain of pups of hyperhomocysteinemic dams. Increased DNA fragmentation and p53 mRNA expression was observed in the brain of pups of homocysteine-treated rats, while a significant reduction was seen in the levels of anti-apoptotic Bcl-2 levels. Melatonin administration prevented markers of oxidative stress and biochemical signs of apoptosis. In conclusion, therapeutic administration of melatonin protects against the induction of oxidative stress and neural tissue injury and might prevent congenital malformations of fetal brain caused by maternal hyperhomocysteinemia.

The present study was carried out to determine the in vitro hepatoprotective activity of ethanolic extract from Eichhornia crassipes (EEEC) flowers using the CCl4-challenged BRL3A cell model. Hepatoprotective activity of EEEC (at concentrations of 50, 100 and 200 μg/mL) and standard drug silymarin (200 μg/mL) was evaluated against CCl4 induced toxicity using BRL3A cell line by measuring the cell viability, aspartate aminotransferase (AST), alanine aminotransaminase (ALT), lactate dehydrogenase (LDH) leakage, lipid peroxidation (LPO) and glutathione level (GSH). Treatment with CCl4 produced a significant decrease in cell viability. In addition, hepatotoxicity was revealed by increased hepatic marker enzymes like AST, ALT and LDH paralleled with elevated lipid peroxidation and decline in GSH levels. The toxicity induced by CCl4 in the BRL3A cells was significantly recovered by treatment with EEEC. The tested doses (100 and 200 μg/mL) significantly (P <0.01) reduced the CCl4 induced elevation of AST, ALT and LDH and also restored the altered biochemical parameters. These findings provide a basis for confirming the traditional uses of E. crassipes in treating liver ailments.

To investigate and compare the antioxidant activities of salvianolic acid B (SalB) and Ginkgo biloba extract (EGb 761) in aqueous solution, rat microsomes and the cellular system. Superoxide anion (O2-.) was generated using xanthine/xanthine oxidase system and phenazine methosulate/NADH system, and the effects of SalB and EGb 761 on the generation of O2-.were achieved by spectrophotometric measurement of the product formed on reduction of nitro blue tetrazolium. Two different methods were used to assess the scavenging effects of the extracts on hydroxyl radical (. OH): HPLC method was used for quantitation of . OH by oxy-radical trapping of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to form DMPO-OH adducts in Fe2+-EDTA-H2O2 system. To confirm the HPLC data, .OH was also measured by spectrophotometry using a commercial detection kit. The anti-lipid peroxidation effects of the extracts in microsomes of rat brain, liver and kidney induced by ascorbate-NADPH were determined by thiobarbituric acid (TBA) method. The protective effects of the extracts on peroxide hydrogen (H2O2)-induced oxidative damage in SH-SY5Y cells were investigated by assessing cell viability assay, the level of lipid peroxidation, and the lactate dehydrogenase(LDH) release. Both SalB and EGb 761 were able to scavenge O2-. and . OH, inhibit lipid peroxidation of microsomes, and protect SH-SY5Y cells against H2O2-induced oxidative damage. However, the concentration of SalB was far lower than that of EGb 761 when a similar effect was obtained. The antioxidant efficiency of SalB was greater than that of EGb 761. These results suggest that SalB, like EGb 761, has promising potential in treating oxidative damage-derived neurodegenerative disorders.