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Stabilizing mixed fatty acid and phthalate ester monolayer on artificial seawater
2018
Li, Siyang | Du, Lin | Zhang, Qingzhu | Wang, Wenxing
Phthalate esters which are widely used as industrial chemicals have become widespread contaminants in the marine environment. However, little information is available on the interfacial behavior of phthalate esters in the seawater, where contaminants generally occur at elevated concentrations and have the potential to transfer into the atmosphere through wave breaking on sea surface. We used artificial seawater coated with fatty acids to simulate sea surface microlayer in a Langmuir trough. The interactions of saturated fatty acids (stearic acid (SA) and palmitic acid (PA)) with one of the most abundant phthalate esters (di-(2-ethylhexyl) phthalate (DEHP)), were investigated under artificial seawater and pure water conditions. Pure DEHP monolayer was not stable, while more stable mixed monolayers were formed by SA and DEHP on the artificial seawater at relatively low surface pressure. Sea salts in the subphase can lower the excess Gibbs free energy to form more stable mixed monolayer. Among the ten components in the sea salts, Ca²⁺ ions played the major role in condensation of mixed monolayer. The condensed characteristic of the mixed SA (or PA)/DEHP monolayers suggested that the hydrocarbon chains were ordered on artificial seawater. By means of infrared reflection-absorption spectroscopy (IRRAS), we found that multiple sea salt mixtures induced deprotonated forms of fatty acids at the air–water interface. Sea salts can improve the stability and lifetime of mixed fatty acid and phthalate ester monolayer on aqueous droplets in the atmosphere. Interfacial properties of mixed fatty acid and phthalate ester monolayers at the air–ocean interface are important to help understand their behavior and fate in the marine environment.
显示更多 [+] 显示较少 [-]Allelopathic effects and potential allelochemical of Sargassum fusiforme on red tide microalgae Heterosigma akashiwo
2021
Sun, Siqi | Hu, Shanshan | Zhang, Bo | Sun, Xue | Xu, Nianjun
In this study, we aim to explore the allelochemicals of marine brown algae Sargassum fusiforme and the mechanism of allelopathy effect on Heterosigma akashiwo. Six potential allelopathic substances, palmitic acid, arachidonic acid, α-linolenic acid (ALA), fucosterol, 24-hydroperoxy-24-vinylcholesterol, and saringosterowere, were isolated and identified from S. fusiforme by column chromatography, NMR, TOF-MS and GC‐MS analyses. The ALA and 24-hydroperoxy-24-vinylcholesterol showed remarkable inhibitory activities on H. akashiwo growth. Besides, the allelopathic mechanism between the ALA and H. akashiwo was preliminarily investigated. The results indicated that the activities of SOD and POD of H. akashiwo gradually decreased under high ALA concentration. The reduction of photosynthetic pigments and chlorophyll fluorescence parameters, as well as apparent electron transport rate in H. akashiwo cells, aggravated gradually with increasing the concentration of the ALA. In summary, this study revealed the responses of morphology and physiology of H. akashiwo when exposed by ALA, while revealing the potential of macroalgae in red tide control.
显示更多 [+] 显示较少 [-]Monosaccharide anhydrides, monocarboxylic acids and OC/EC in PM1 aerosols in urban areas in the Czech Republic
2015
Křůmal, Kamil | Mikuška, Pavel | Večeřa, Zbyněk
The concentrations of monosaccharide anhydrides (levoglucosan, mannosan, galactosan), monocarboxylic acids (alkanoic acids C7 – C20 and two unsaturated fatty acids, palmitoleic and oleic acids) and organic and elemental carbon in PM1 aerosol samples were measured in two cities of the Czech Republic (Brno and Šlapanice) in winter and summer seasons of 2009 and 2010.Mass concentrations of PM1 aerosols (determined by weighing filters with collected aerosol) were higher in winter than in summer in both 2009 and 2010, in Brno as well as in Šlapanice.Organic compounds were analysed by GC–MS. The sum of average atmospheric concentration of monosaccharide anhydrides (MAs) in PM1 aerosol in Brno and Šlapanice was 273 and 646 ng m−3 in winter and 20–42 ng m−3 in summer. The higher concentrations of MAs in PM1 aerosols in winter seasons indicate higher frequency of biomass combustion than in summer seasons. Levoglucosan was the most abundant monosaccharide anhydride. Contrary to MAs, the concentrations of majority monocarboxylic acids were higher in summer (153–221 ng m−3) than in winter (116–206 ng m−3) in both cities in 2009 and in 2010. Palmitic acid was the most abundant monocarboxylic acid.The concentrations of both organic (OC) and elemental (EC) carbon were higher in winter than in summer, which corresponds especially to higher biomass burning and coal combustion in the frame of residential heating within winter seasons. Mass concentrations of the analysed aerosol samples were counted, i.e., OCBB and ECBB (biomass burning), OCFF and ECFF (fossil fuel combustion), and OCBIO (biogenic sources).Higher concentrations of MAs and PM1, OC and EC in winter seasons, could be caused not only by larger emissions from biomass or coal combustion, but also by less dispersion due to different atmospheric conditions.
显示更多 [+] 显示较少 [-]Natural antifouling compounds produced by a novel fungus Aureobasidium pullulans HN isolated from marine biofilm
2013
Gao, Min | Su, Rongguo | Wang, Ke | Li, Xuzhao | Lu, Wei
A fungus, Aureobasidium pullulans, was isolated from marine biofilm and identified. A bioassay-guided fractionation procedure was developed to isolate and purify antifouling compounds from A. pullulans HN. The procedure was: fermentation broth—aeration and addition of sodium thiosulfate–graduated pH and liquid–liquid extraction—SPE purification—GC–MS analysis. Firstly, the fermentation broth was tested for its toxicity. Then it was treated with aeration and addition of sodium thiosulfate, and its toxicity was almost not changed. Lastly, antifouling compounds were extracted at different pH, the extract had high toxicity at pH 2 but almost no toxicity at pH 10, which suggested the toxicants should be fatty acids. The EC50 of the extract against Skeletonema costatum was 90.9μgml−1, and its LC50 against Balanus amphitrete larvae was 22.2μgml−1. After purified by HLB SPE column, the EC50 of the extract against S. costatum was 49.4μgml−1. The myristic and palmitic acids were found as the main toxicants by GC–MS.
显示更多 [+] 显示较少 [-]Characterization of allelochemicals from Pistia stratiotes extracts and their effects on the growth and physiology of Microcystis aeruginosa
2021
Lourenção, Anderson | Mecina, Gustavo F. | Cordeiro-Araújo, Micheline K. | Bittencourt-Oliveira, Maria C. | Chia, Mathias A. | Bronzel-Júnior, João L. | Granero, Filipe O. | Silva, Luciana P. | da Silva, Regildo M. G.
Due to the public and environmental health impact of cyanotoxins, investigations have been focused on finding environmental friendly algaecides from aquatic plants. The present study had the objective to evaluate the population control and physiological response of Microcystis aeruginosa (Kützing) Kützing (strain BCCUSP232) exposed to Pistia stratiotes L. extracts. Aqueous and ethanolic extracts of P. stratiotes at different concentrations (10, 25, and 50 mg L⁻¹) were submitted to M. aeruginosa and reduced significantly (p<0.05) the cyanobacterium cell density. The ethanolic extract presented the greatest growth inhibition of the strain at the highest concentration. During exposure to P. stratiotes extracts, intracellular hydrogen peroxide levels, malondialdehyde content, and antioxidant enzymes (peroxidase, catalase, and glutathione S-transferase) activities increased in M. aeruginosa, while total protein concentration decreased when compared to the control group. Superoxide dismutase (SOD) activities presented a sharp decline, suggesting superoxide radical and peroxide accumulation. This implied that SOD was a target for bioactive substance(s) from aqueous and ethanolic extracts of P. stratiotes. Phytochemical screening of the extracts revealed that the ethanolic extract presented 93.36 mg gallic acid equivalent (GAE) per gram dry weight (g⁻¹ DW) total polyphenols and 217.33 mg rutin equivalent (RE) per gram dry weight total flavonoids, and for the aqueous extract, 5.19 mg GAE g⁻¹ DW total polyphenols and 11.02 mg RE g⁻¹ DW total flavonoids were detected. Gas chromatography (GC)/mass spectrometry (MS) analyses of the ethanolic and aqueous extracts presented palmitic acid ethyl ester as major allelochemical. In view of these results, it can be concluded that P. stratiotes showed potential in controlling M. aeruginosa populations.
显示更多 [+] 显示较少 [-]Nutritive value of quinoa (Chenopodium quinoa) as a feed for ruminants: in sacco degradability and in vitro gas production
2022
Ebeid, Hossam Mahrous | Kholif, Ahmed Eid | El-Bordeny, Nasr | Chrenkova, Maria | Mlynekova, Zuzana | Hansen, Hanne Helene
Replacement of conventional feedstuffs with inexpensive and non-conventional ingredients such as quinoa may improve animal performance and the quality of their products. Quinoa supplementation is believed to have a good nutritive value as a ruminant feed, but evidence is scarce. The present experiment aimed to evaluate the nutritive value of whole, dried quinoa plant (Chenopodium quinoa) as a feed for ruminants. In the first experiment, the in sacco technique was used to evaluate nutrient disappearance and fermentation kinetics of quinoa. In the second experiment, the in vitro gas production technique was used to evaluate diets with substitution of clover hay with quinoa at 0 (Q0), 15 (Q15), 30 (Q30), and 45% (Q45) of the diets. Proximate analysis showed that quinoa contained about 18.6% crude protein (CP) with oleic acid, arachic acid, linoleic acid, and palmitic acid as the major fatty acids. The in sacco degradability showed that the “a” fraction of dry matter (DM) was low, while the fraction “b” was high for DM and CP. Replacing clover hay with quinoa did not affect gas or methane production; however, Q30 treatment quadratically increased (P < 0.05) its production. It is concluded that quinoa can be used as a feed for ruminants and can replace clover hay up to 45% in the diet.
显示更多 [+] 显示较少 [-]Bioactive phytochemicals from Salvia officinalis attenuate cadmium-induced oxidative damage and genotoxicity in rats
2021
Rashwan, Hanan M. | Mohammed, Hagar E. | El-Nekeety, Aziza A. | Hamza, Zeinab K | Abdel-Aziem, Sekena H. | Hassan, Nabila S. | Abdel-Wahhab, Mosaad A.
This study was conducted to identify the bioactive phytochemicals in Salvia officinalis essential oil, to determine the polyphenols in the aqueous extract (SOE), and to evaluate their protective role against cadmium (Cd)-induced oxidative damage and genotoxicity in rats. Six groups of female rats were treated orally for 2 weeks including the control group, CdCl₂-treated group, SOE-treated groups at low or high dose (100 and 200 mg/kg b.w), and CdCl₂ plus SOE-treated groups at the two doses. The GC-MS analysis identified 39 compounds; the main compounds were 9-octadecenamide, eucalyptol, palmitic acid, and oleic acid. However, the HPLC analysis showed 12 polyphenolic compounds and the majority were coumaric acid, chlorogenic acid, coffeic acid, catechin, vanillin, gallic acid, ellagic acid, and rutin. In the biological study, rats received CdCl₂ displayed severe disturbances in liver and kidney indices alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb), total protein (TP), total bilirubin (T. Bil), direct bilirubin (D. Bil), creatinine, uric acid, and urea, lipid profile, tumor necrosis factor-alpha (TNF-α), alpha-fetoprotein (AFP) and CEA), glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), malondialdehyde (MDA), nitric oxide (NO), gene expressions, DNA fragmentation, and histological alterations in the liver and kidney tissue. SOE showed a potent antioxidant and mitigated these alterations in serum and tissue. Moreover, the high dose succeeded to normalize most of the tested parameters and histological features. It could be concluded that S. officinalis is a promising source for bioactive compounds with therapeutic benefits against environmental toxicants.
显示更多 [+] 显示较少 [-]Organic and aqueous extraction of lipids from birch pollen grains exposed to gaseous pollutants
2021
Farah, Jinane | Choël, Marie | de Nadaï, Patricia | Balsamelli, Joanne | Gosselin, Sylvie | Visez, Nicolas
The lipid fraction of birch pollen grains (BPGs) is not yet fully described, although pollen lipid molecules may play a role in the allergic immune response. The mechanisms by which atmospheric pollutants modify allergenic pollen grains (PGs) are also far from being elucidated despite high potential effects on allergic sensitization. This work is a contribution to a better description of the lipid profile (both external and cytoplasmic) of BPGs and of alterations induced by gaseous air pollutants. Several lipid extractions were performed using organic and aqueous solvents on BPGs following exposure to ozone and/or nitrogen dioxide and under conditions favoring the release of internal lipids. Ozone reacted with alkenes to produce aldehydes and saturated fatty acids, while nitrogen dioxide was shown to be unreactive with lipids. NO₂ exhibited a protective effect against the reactivity of alkenes with ozone, probably by competition for adsorption sites. The decreased reactivity of ozone during simultaneous exposure to NO₂/O₃ raised the possibility of a Langmuir-Hinshelwood mechanism. Oxidation reactions induced by exposure of BPGs to ozone did not substantially modify the extraction of lipids by aqueous solvent, suggesting that the bioaccessibility of lipids was not modified by oxidation. On the contrary, the rupture of PGs appeared to be a key factor in enhancing the bioaccessibility of bioactive lipid mediators (linoleic and α-linolenic acids) in an aqueous solution. The internal lipid fraction of BPGs has specific characteristics compared with external lipids, with more abundant hexadecanoic acid, tricosanol, and particularly unsaturated fatty acids (linoleic and α-linolenic acids). Several mechanisms of action of gaseous pollutants on allergenic pollen were identified in this study: gaseous air pollutants can (i) modify the external lipid fraction by reactivity of alkenes, (ii) adsorb on the surface of PGs and be a source of oxidative stress after inhalation of PGs, and (iii) promote the release of cytoplasmic bioactive lipids by facilitating pollen rupture.
显示更多 [+] 显示较少 [-]Temperature and extraction methods effects on yields, fatty acids, and tocopherols of prickly pear (Opuntia ficus-indica L.) seed oil of eastern region of Morocco
2022
Kadda, Salma | Belabed, Abdelmadjid | Loukili, El Hassania | Hammouti, Belkheir | Fadlaoui, Soufiane
The present study focuses on the effect of temperature and extraction methods on the yields, chemical quality, fatty acids, and tocopherols of the oil extracted from the seeds of Opuntia ficus-indica, collected in the eastern region of Morocco. Our results revealed the effect of temperature that when we increase the temperature used, the yields also increase; the results also showed that this high temperature does not affect the physicochemical properties, fatty acids, and tocopherols. Thus, the results of this study revealed that the prickly pear is a rich source of oil; the obtained oil yields varied from 12.49%±0.09 for mechanical extraction, 11.46±0.10 for chemical extraction, and 10.52%±0.09 for maceration. The main fatty acids founded in Opuntia ficus-indica are linoleic acid 75.80%±0.10 (chemical), 74.07%±0.14 (maceration), and 71.59%±0.14 (mechanical) and palmitic acid 17.32%±0.02 (chemical), 22.419%±0.06 (maceration), and 26.58%±0.00 (mechanical); prickly pear oil could be classified as a linoleic acid. The physicochemical properties of Opuntia ficus-indica seed oils such as acid index mgKOH/g oil (4,376±0.10, 5.854±0.03, 5.667±0.07), saponification value mgKOH/g oil (181.12 ±0.18, 183.77±1.23, 179.08±3.45), and peroxide value 20milieq/Kg (5.75±0.08, 6±0.06, 5.97±0.04) for mechanical, chemical, and maceration extraction, respectively, density, and refractive index were all found to be in good accordance with quality criteria for both pure and fresh oils. Among the tocopherols found, a high value of γ-tocopherol was detected in mechanical extraction with 502.04±0.76 mg/kg, followed by chemical extraction and maceration with 430.12±0.61mg/kg and 315.47±0.96 mg/kg, respectively.
显示更多 [+] 显示较少 [-]Characterization of a fatty acid-binding protein from the Pacific oyster (Crassostrea gigas): pharmaceutical and toxicological implications
2021
Tisca, Juliana F. | dos Santos, Karin | Pessati, Tomás B. | Zacchi, Flávia L. | Soares, Fabíola S. | Oliveira, Vanessa A. | Bebianno, Maria J.A.F. | Bainy, Afonso C.D. | Razzera, Guilherme
Pharmaceuticals and their metabolites constitute a class of xenobiotics commonly found in aquatic environments which may cause toxic effects in aquatic organisms. Several different lipophilic molecules, including some pharmaceuticals, can bind to fatty acid-binding proteins (FABPs), a group of evolutionarily related cytoplasmic proteins that belong to the intracellular lipid-binding protein (iLBP) family. An oyster FABP genome-wide investigation was not available until a recent study on gene organization, protein structure, and phylogeny of Crassostrea gigas iLBPs. Higher transcript levels of the C. gigas FABP2 gene were found after exposure to sewage and pharmaceuticals. Because of its relevance as a potential biomarker of aquatic contamination, in this study, recombinant FABP2 from C. gigas (CgFABP2) was successfully cloned, expressed, and purified, and in vitro and in silico assays were performed using lipids and pharmaceuticals. This is the first characterization of a protein from the iLBP family in C. gigas. Homology modeling and molecular docking were used to evaluate the binding affinities of natural ligands (palmitic, oleic, and arachidonic acids) and pharmaceuticals (ibuprofen, sodium diclofenac, and acetaminophen). Among the tested fatty acids, CgFABP2 showed preference for palmitic acid. The selected pharmaceuticals presented a biphasic-binding mode, suggesting a different binding affinity with a preference for diclofenac. Therefore, the approach using circular dichroism and in silico data might be useful for ligand-binding screening in an invertebrate model organism.
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