Explore the vast range of titles available.

The present study evaluates the production of l-asparaginase enzyme from the seaweeds of Ulva intestinalis L. (green), Lobophora variegata L. (brown), and Halymenia dilatata L. (red). The concentrations of ammonia and protein are tested in all three seaweeds. Among them, Ulva intestinalis contained a higher concentration of ammonia and protein with values of 404.166 ± 33.815 mg/mL and 8.233 ± 0.109 mg/mL, respectively. The HPLC results indicated that Lobophora variegata showed a higher peak (5) area percentage with a value of 35.911%, followed by Halymenia dilatata, which showed a peak (5) area percentage of 35.406%. Finally, Ulva intestinalis showed a peak (5) area percentage of 32.063. However, the HPLC results of the l-asparaginase enzyme (extracted from the seaweeds) showed the highest peak (1) area percentage with a value of 100%. These findings show that the l-asparaginase enzyme extracted from these seaweeds might be utilized in food processing and pharmacological medicines. Further studies are needed to explore the biological activity of the l-asparaginase enzyme extracted from these seaweeds.

The present study evaluated the sequential biodiesel-bioethanol production from seaweeds. A total of 22 macroalgal species were collected at different seasons and screened based on lipid and carbohydrate contents as well as biomass production. The promising species was selected, based on the relative increase in energy compounds (REEC, %), for further energy conversion. Seasonal and annual biomass yields of the studied species showed significant variations. The rhodophyte Amphiroa compressa and the chlorophyte Ulva intestinalis showed the highest annual biomass yield of 75.2 and 61.5 g m −2 year −1 , respectively. However, the highest annual carbohydrate productivity (ACP) and annual lipid productivity (ALP) were recorded for Ulva fasciata and Ulva intestinalis (17.0 and 3.0 g m −2 year −1 , respectively). The later was selected for further studies because it showed 14.8% higher REEC value than Ulva fasciata. Saturated fatty acids (SAFs) showed 73.4%, with palmitic acid as a dominant fatty acid (43.8%). Therefore, biodiesel showed high saturation degree, with average degree of unsaturation (ADU) of 0.508. All the measured biodiesel characteristics complied the international standards. The first route of biodiesel production (R1) from Ulva intestinalis showed biodiesel recovery of 32.3 mg g −1 dw. The hydrolysate obtained after saccharification of the whole biomass (R2) and lipid-free biomass (R3) contained 1.22 and 1.15 g L −1 , respectively, reducing sugars. However, bioethanol yield from R3 was 0.081 g g −1 dw, which represented 14.1% higher than that of R2. Therefore, application of sequential biofuel production using R3 resulted in gross energy output of 3.44 GJ ton −1 dw, which was 170.9% and 82.0% higher than R1 and R2, respectively. The present study recommended the naturally-grown Ulva intestinalis as a potential feedstock for enhanced energy recovery through sequential biodiesel-bioethanol production.

The growing population requires sustainable, environmentally-friendly crops. The plant growth-enhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown. We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana . Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract <0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation. An abscisic-acid-insensitive mutant, abi1 , showed altered sensitivity to germination- and root growth-inhibition. Ethylene- and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germination-inhibition. Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al 3+ ). Ethylene and cytokinin have been suggested to function in Al 3+ -mediated root growth inhibition: our data suggest that if Ulva Al 3+ levels inhibit root growth, this is via a novel mechanism. We suggest algal extracts should be used cautiously as fertilisers, as the inhibitory effects on early development may outweigh any benefits if the concentration of extract is too high.

Water-soluble sulfated polysaccharides extracted from Ulva intestinalis and fractionated using DEAE Sepharose fast flow column to identify their molecular properties and macrophage cells stimulating activities. Crude and fractions (F1 and F2) were formed of neutral sugars (58.7–74.7%), sulfates (6.2–24.5%), uronic acids (4.9–5.9%) and proteins (3.2–10.4%). Different levels of sugar constituents including rhamnose (30.1–39.1%), glucose (39.0–48.4%), galactose (0.0–15.8%), xylose (8.5–11.3) and arabinose (0.0–5.1%). The molecular weight (Mw) of crude and fractionated polysaccharides ranged from 87.1 × 103 to 194.1 × 103 (g/mol). Crude polysaccharides were not toxic to RAW264.7 cells and fractions induced cell proliferation. Fraction F1 stimulated RAW264.7 cells to release considerable amounts of nitric oxide, IL-1β, TNF-α, IL-6, IL-10 and IL-12 cytokines. The main backbone of the most immunostimulating polysaccharide (F1) was consisted of mixed linkages of (1 → 2)-linked rhamnose and (1 → 2)-linked glucose residues. [Display omitted] •A purified sulfated polysaccharide (F1) was obtained from Ulva intestinalis.•Polysaccharide F1 was found to be the most immunostimulating polysaccharide.•Fraction F1 had the lowest molecular weight and the highest sulfate content.•Polysaccharide F1 was mainly composed of mixed (1 → 2)-linked rhamnose and (1 → 2)-linked glucose residues.

Angiotensin I-converting enzyme (ACE) inhibitory peptides derived from seaweed represent a potential source of new antihypertensive. The aim of this study was to isolate and purify ACE inhibitory peptides (ACEIPs) from the protein hydrolysate of the marine macroalga Ulva intestinalis. U. intestinalis protein was hydrolyzed by five different proteases (trypsin, pepsin, papain, α-chymotrypsin, alcalase) to prepare peptides; compared with other hydrolysates, the trypsin hydrolysates exhibited the highest ACE inhibitory activity. The hydrolysis conditions were further optimized by response surface methodology (RSM), and the optimum conditions were as follows: pH 8.4, temperature 28.5 °C, enzyme/protein ratio (E/S) 4.0%, substrate concentration 15 mg/mL, and enzymolysis time 5.0 h. After fractionation and purification by ultrafiltration, gel exclusion chromatography and reverse-phase high-performance liquid chromatography, two novel purified ACE inhibitors with IC50 values of 219.35 μM (0.183 mg/mL) and 236.85 μM (0.179 mg/mL) were obtained. The molecular mass and amino acid sequence of the ACE inhibitory peptides were identified as Phe-Gly-Met-Pro-Leu-Asp-Arg (FGMPLDR; MW 834.41 Da) and Met-Glu-Leu-Val-Leu-Arg (MELVLR; MW 759.43 Da) by ultra-performance liquid chromatography-tandem mass spectrometry. A molecular docking study revealed that the ACE inhibitory activities of the peptides were mainly attributable to the hydrogen bond and Zn(II) interactions between the peptides and ACE. The results of this study provide a theoretical basis for the high-valued application of U. intestinalis and the development of food-derived ACE inhibitory peptides.

Supplementation of seaweed to fish diets has been widely reported to improve growth and immunity. This study was conducted to investigate the effect of sulfated polysaccharide extract from the green alga Ulva intestinalis and the red alga Gracilariopsis persica as a dietary supplement on growth performance, fatty acid profile, stress response, antioxidant enzyme activity, and nonspecific immune responses in rainbow trout (Oncorhynchus mykiss) (15.74 ± 0.48 g). The five experimental diets include control (without sulfated polysaccharide), 0.5SPG (0.5 g kg−1 sulfated polysaccharide from G. persica), 1.5SPG (1.5 g kg−1 sulfated polysaccharide from G. persica), 0.5SPU (0.5 g kg−1 sulfated polysaccharide from U. intestinalis), and 1.5SPU (1.5 g kg−1 sulfated polysaccharide from U. intestinalis) were formulated and fed to fish for 8 weeks. Results of growth trial indicated a significant enhancement of growth performance of fish fed 1.5SPG, 0.5SPU, and 1.5SPU as compared with control. Although there was no significant difference in the fatty acid profile of muscle, fish fed the 1.5SPG diet showed higher protein and lower lipid contents than the control group. While the lysozyme and complement activity of serum was significantly enhanced in fish fed 1.5SPG and 1.5 SPU diets, superoxide dismutase in these treatments was lower than the control group. Furthermore, the amount of cortisol in individuals fed experimental diets after 3-h confinement stress was lower than fish fed the control diet. To conclude, in consideration of all factors, we suggest the potential benefits of using 1.5SPG diet in the aquaculture industry as a diet supplementation.

Ulva intestinalis (UI) is widely available edible seaweed and has potential to be introduced as functional food items in Bangladesh. However, potential health hazards of this seaweed with biotoxicity assays and its relation to heavy metal contents were not evaluated previously. With these objectives, toxic effects of UI collected from floating raft culture in Monkhali Beach was evaluated using various organisms such as Chlorella vulgaris , Artemia salina , Daphnia magna , and Lactuca sativa . In relation to this effects, heavy metal concentrations (Fe, Cr, Ni, Cu, Zn, Pb, Cd, and As) and its potential health hazards were subsequently analyzed. The results showed that UI water extract had positive effects on the survivability and growth of the all-test organisms over different time periods, with minimal LC50 values, indicating no toxic to tested organisms. However, increased levels of total dissolved solids and electrical conductivity were observed as extract concentrations increased but considered to be safe below 5 mg kg −1 , as compared to control. Moreover, Fe, Cr, Ni, Cu and Zn (43.60, 0.10, 0.44, 0.07, 0.27 and 0.13 mg kg −1 of dry weight, respectively) in UI were found to be low levels compared to previous studies, in addition, Cd and As remained not detected. No significant health risk (HQ < 1) and target carcinogenic risk were found. Therefore, UI could be utilized as functional foods or nutraceuticals for health-conscious consumers of Bangladesh without having potential risks.

Response surface methodology was employed to optimize the ultrasound-assisted extraction of crude polysaccharides from the cell wall of Ulva intestinalis . The impacts of four independent variables including extraction temperature ( X 1 50–90 °C), extraction time ( X 2 20–40 min), the ratio of water to raw material ( X 3 50–70), and pH ( X 4 7–9) were investigated through Box–Behnken experimental design. The experimental data were adequately fitted into a second-order polynomial model, and optimized conditions were as follows: extraction temperature 66 °C, extraction time 40 min, water to raw material ratio 50, and pH 7.0. Fourier transform infrared (FT-IR) results revealed the presence of sulfate esters indicated by the peaks at 850 and 1256 cm −1 derived from the bending vibration of C–O–S and stretching vibration of S–O of sulfate. The experimental yield achieved under these conditions was 8.30 %, which was well in close agreement with the value (8.36 %) predicted by the response surface methodology (RSM) model. The extracted polysaccharides exhibited appreciable 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging and reducing power as well as macrophage-stimulating capacity indicating their potential value for health and food industry.

Ulva intestinalis (previously called Enteromorpha intestinalis) is the principal marine macroalga growing in isolated rockpools along the Swedish west coast. Given that this alga can take up HCO super(-) sub(3) under the conditions of high pH and low concentrations of inorganic carbon (Ci) that it creates in those pools, we hypothesized that those conditions would be unfavourable for the photosynthetic performance of other algae such that they would not be able to grow in the same pools. This was tested by transferring 2 of the most common macroalgae, Fucus vesiculosus and Chondrus crispus, from the shallow waters of a bay adjacent to some rockpools, to 2 rockpools containing U. intestinalis. Both photosynthetic electron transport rates (ETR) and maximal quantum yields (F sub(v)/F sub(m)) were measured 3 d later. Similar measurements were also performed throughout the day in simulated outdoor rockpools where the 3 species were kept either alone or together for 24 h. It was found that midday ETRs were repressed for all species in the (upper) rockpool as compared to the open bay, but more so for the transferred F. vesiculosus and C. crispus (33 and 0.6%, respectively, of the bay values) than for U. intestinalis (58%). Also, C. crispus showed exceptionally repressed midday F sub(v)/F sub(m) values in the rockpools (some 22% of that in the bay), and had largely photobleached after 3 d. Similarly, ETRs declined in the simulated rockpools during the day, especially for C. crispus when the other algae were present (to 7% of morning values, compared to 36% when alone). Also, F sub(v)/F sub(m) declined in the simulated rockpools during the day, indeed much more so for F. vesiculosus and C. crispus when the other algae were present (to ca. 12 and 10% of morning values as compared to 76 and 54%, respectively, when alone). As in the rockpools, the latter alga photobleached when kept together with the other species, but not when alone. Based on these results, and considering their different Ci utilisation mechanisms, it was concluded that the absence in rockpools of algae such as those tested here may be largely due to the adverse conditions of high pH and low Ci concentrations caused by the photosynthetic traits of U. intestinalis.

The increasing limitations of antibiotic therapy, due to adverse effects and the alarming rise of bacterial resistance, underscore the urgent need for novel antimicrobial alternatives. This study investigated the antibacterial and antibiofilm activities of crude extracts from the green seaweed Ulva intestinalis as potential natural substitutes for conventional antibiotics. Samples were collected from the Mediterranean coast of Alexandria, Egypt, and extracted using ethanol, methanol, and acetone. The antibacterial activity against Staphylococcus aureus was assessed via the agar well diffusion method. Among the tested extracts, the ethanol extract at 200 µg/mL showed the largest inhibition zone (35.03 ± 0.04 mm), whereas the acetone extract exhibited the lowest activity (15.7 ± 0.09 mm) at the same concentration. The antibiofilm efficacy, evaluated using a 96-well microtiter plate assay, revealed that the methanolic extract inhibited biofilm formation by 91.26% at 200 µg/mL, the highest tested concentration. GC–MS analysis identified several bioactive constituents, including pentadecane, eicosane, and 2,6,10,14-tetramethylpentadecane, whereas FTIR spectra confirmed the presence of phenolic, alcoholic, aliphatic, ketonic, aromatic, and amine functional groups. Molecular docking studies demonstrated strong binding affinities of selected compounds toward key S. aureus targets (RNA polymerase, DNA gyrase, and PBP2a), suggesting potential mechanisms involving disruption of transcription, DNA replication, and β-lactam resistance. Overall, these results highlight U. intestinalis as a promising marine-derived source of antimicrobial and antibiofilm agents with potential pharmaceutical applications.