Journal of Aquatic Ecology

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Marine animals are among the most important sources of natural products with biological activities because of their secondary metabolites. Many compounds were extracted, purified, identified and studied for their antioxidant, cytotoxic, anti-inflammatory and antibacterial effects from sea cucumber However, very few investigations are available on Persian Gulf sea cucumbers. The antioxidant activities of organic extracts (n-Hexan, Ethyl acetate and Methanol) from four organs of Holothuria parva and H. leucospilota in this study were tested. The results showed that methanolic extract of digestive tubule of H. parva contains the highest level of IC50 (369.64 µg/ml), while the lowest level was obtained from Ethyl acetate extract of digestive tubule of H. leucospilota (1451.35 µg/ml). n-Hexan extracts didn’t have any efficiency in scavenging of DPPH free radical. This study indicated that some form of antioxidant activities are present in the biologic extracts of Holothuria parva and H. leucospilota.

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Iodine is the main ingredient produced by the thyroid hormone, which playa a central role in the metabolism and the immune system. The present study aims to evaluate the effects of feeding Artemia fransiscana enriched with potassium iodide on antioxidant and immune gene expression in zebra fish (Danio rerio). Zebra larvae with an average weight of 2±0.01 mg were randomly distributed into 4 treatments with 3 replicates. The treatments were larvae fed 0.2, 0.5 and 1 mg/L potassium iodide enriched Artemia for 2 months. Result showed that potassium iodide significantly (P≤0.05) increased antioxidant and immune gene expression in zebra fish and the intensity of changes followed a dose- dependent manner. The 1 mg/L potassium iodide treated fish showed the highest gene expression in all studied genes. Due to changes in the expression of immune and antioxidant related genes, it appeared that potassium iodide could improve immune and antioxidant function in zebrafish.                     

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Screening bacteria for bioactive compounds is the first step in the drug discovery programs. The aim of the present research was to achieve cytotoxic and antioxidant metabolites from actinobacteria of Persian Gulf sediments and to investigate the effects of combinations of seven treatments and six isolation media on the selective isolation process. A total of 395 actinobacterial isolates were collected from 12 sediment samples. Heat treatment and M₆ medium were exhibited maximum efficiency of 34.59% and 32.82% isolation, respectively. Preliminary characterization results revealed the dominant distribution of Streptomyces like isolates in all investigated stations. Streptomyces isolates distribution followed a depth dependent frequency pattern. Approximately, 27.45% of the examined isolates could scavenge 90% of DPPH radicals in 1250 µg/ml final concentration. Exudated metabolites of potent isolates could scavenge DPPH radicals with IC50 ranges from 411 to 670 µg/ml. The results of cytotoxic activity showed that 54.9% of examined isolates exhibited LC₅₀ lower than 1000µg/mL against Artemia cells_. Extracted metabolites from 12 potent isolates exhibited LC₅₀ range from 236.3 to 565.3 µg/ml. These results suggest the widespread distribution of the antioxidant and cytotoxic producing actinobacteria in Persian Gulf sediments and represent actinobacterial isolates as promising candidates for the discovery of microbial derived bioactive compounds.

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Seaweeds are one of the most important resources for extraction of natural bioactive components. In the present study, effect of different solvents (methanol 100%, methanol 70%, acetone 100%, and acetone 70%) was evaluated on the phenolic components extraction and antioxidant properties of two brown seaweed species (N. zanardinii and P. australis) from Chabahar coasts. Antioxidant activities of the first extract and its fractions including chloroform, dichloromethane, ethyl acetate and aqueous phase were measured using total phenolic content, DPPH free radical scavenging activity, reduction power and metal chelating activity methods. Phenol content and antioxidant properties were higher in 100% methanolic extract compared to other treatments for both algae. Ethyl acetate fraction of N. zanardinii showed the best antioxidant activities. Antioxidant properties of N. zanardinii were considerably higher than P. australis. The results showed that N. zanardinii can be considered as potential sources of natural antioxidants.

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The purpose of this study was to evaluate the antioxidant power of knife shells, Solen dactylus using DPPH, reducing power, and TAC methods. Twenty shells were sampled at Ghouban Estuary in autumn and spring. 2 ml of pure methanol was added per 1 g of sample, and centrifuged at 11,000 rpm for 30 minutes. Then the supernatant was removed and transferred to the rotary machine for 5 minutes. In this method, 100 μl of the sample extract (0.5 g/l concentration) was added to 2 ml of DPPH (0.6 mm DPPH in 95% methanol) in a test tube and distilled into 3 ml distilled water. The reaction solution was then shaken vigorously and allowed to stand at room temperature in the dark for 30 minutes. The optical absorbance of the solution was measured in a wavelength of 517 nm using a spectrophotometer. In antioxidant studies, three different methods were used. DPPH, reducing power, and total antioxidants. Results of the DPPH method showed an average absorption of 67.79% between 2 seasons. In the absorption power reduction method, 62.2% was observed in autumn and 0.98 in spring. In the total antioxidant strength method, by comparing the absorbance of the extract solution with the absorption of ascorbic acid standards at concentrations of 50 to 400 mg/l, the total antioxidant in the autumn was 85.3 and 165.1 µg/ml in the spring.

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In this study, the effect of dietary supplementation with mineral and Nano forms of two essential elements, iron and copper was investigated on the blood biochemical profile, antioxidant, and immunity performance of Schizothorax Zarudnyi with an average weight of 23.97±0.45 g. The fish were fed with diets containing (1)  no copper and iron supplement (basal diet), (2) 150 mg/kg of mineral iron supplement, (3) 3 mg/kg of mineral copper supplement, (4) 150 and 3 mg/kg of iron and mineral copper supplement respectively, (5) 150 mg/kg of iron nanoparticle supplement, (6) 3 mg/kg of copper nanoparticle supplement, and (7) 150 and 3 mg/kg of iron nanoparticles and copper nanoparticle supplement, respectively for 60 days. Dietary addition of iron and copper in both forms improved blood biochemical profile, antioxidant, and immunity performance compared to the control. The addition of Nano form led to significant improvement in blood parameters and antioxidant defense system compared to the mineral-fed treatments. The simultaneous use of the Nano form of these two elements led to a significant improvement in serum total protein, albumin, globulin, HDL, cholesterol, triglyceride, MDA, GPx, SOD, CAT, C3, ACH50, and serum bactericidal activity compared to other treatments. In conclusion, the simultaneous use of iron and copper at the rate of 150 and 3 mg/kg of diet in Nano form is much more effective than their mineral or individual Nano forms to improve the antioxidant and immune parameters of S. Zarudnyi.

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Due to using of nanoplastics in a wide range of applications such as biosensors, photonics, nanocomposites and etc., and highly enhancement of plastic debris in aqueous environments have raised concerns about the potential effects of these substances on microalgae that are primary producers. The aim of this study was, to investigate the effects of different concentrations (0.25, 2.5, 25, and 250 mg/L) nanopolystyrene particles (PS-NH₂⁺) after 96 hours on the growth, chlorophyll a content, and amount of antioxidant production of microalgae chlorella vulgaris. The growth rate (counting of cells) and chlorophyll a content and amount of antioxidant (measuring optical density/absorbance) were evaluated. The growth and chlorophyll a content showed a decreasing trend than the control group, with increasing concentration of nanoplastic and exposure time (12 days). Also, the results demonstrated that the amounts of antioxidant production in the exposed samples to nano-polystyrene were higher than the control samples. Finally, it`s suggested that this nanoparticle causes acute impacts on this microalgae in a long time and has the ability to affect cellular mechanisms.

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Melanosis is a major problem in the marine crustaceans processing industry particularly on shrimps which can lead to financial loss to producers. The cause of this complication is biochemical reactions of polyphenoloxidase (PPO) enzyme and the formation of the dark pigments on shrimp′s body. The main purpose of the present study was to evaluate the inhibitory effect of secondary metabolites extracted from SC 190 on PPO activity to achieve a potential alternative for chemical inhibitors implemented for control of melanosis on Pacific white shrimp. In this study, the PPO enzyme was extracted from the cephalothorax of shrimp samples and partially purified. The results showed that extracted metabolites from the strain SC 190 isolated from sea cucumber Holothuria scabra represented inhibitory activity on the PPO enzyme with an IC₅₀ value of 60.69 ± 3.76 µg/mL. The bacterial extracted metabolites could scavenge DPPH free radicals with an IC₅₀ value of 45.10±2.14 µg/mL. The result of the toxicity test showed that the extracted metabolites were not toxic to the human umbilical vein endothelial cell lines. Chemical screening approved the existence of phenolic compounds in the extracted bacterial metabolites. Polyphasic identification of SC 190 isolate revealed that it has belonged to Streptomyces genus and its 16S rRNA gene sequence had 99% homology with S. cellulosae. According to the results, the metabolites extracted from Streptomyces sp. Strain SC 190 can be considered as a potential biopreservative in the preservation of Pacific white shrimp.

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Azo group dyes are the most important group of commercial dyes and the widest dyes which are used in various industries. The release of effluents containing these compounds into the environment leads to several problems such as reduced photosynthesis and plant growth, and reduced water quality. In the present study, the effect of three different concentrations (0, 10, 20 mg / L) of Acidic Blue dye 92 (AB92) on the physiological characteristics of aquatic plant Ceratophyllum demersum such as photosynthetic pigments, cyanidin glycoside concentration, the ability to scavenging free radicals and lipid peroxidation were investigated during 7 days. According to results, the amount of chlorophyll a, chlorophyll b, total chlorophyll, and total carotenoid decreased in the concentration of 20 mg / L compared to the control by 15.38, 18, 16.88, and 45.1%, respectively. The concentration of cyanidin glycoside, lipid peroxidation, and antioxidant activity increased in both 10 and 20 mg / L, since at 20 mg / L concentration so that these parameters were increased in comparison with control by 81.8%, 69.5 %, and 14.29 %, respectively. Thus, the presence of both 10 and 20 mg / L of Acidic Blue dye 92 induced antioxidant activity and the risk of oxidative stress for Ceratophyllum demersum.

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In the present study, DPPH free radical scavenging activity, metal chelating activity, reduction power, total phenolic content, pigments content, and fatty acid profile of Dunaliella salina microalgae were investigated. Solvents of methanol, hexane and chloroform in the algae extract concentrations of 0.01, 0.1, and 1 µg/ml was used. The results showed that the highest scavenging of DPPH free radicals was in the methanol extract, and the minimum value was observed in 0.01 hexane extract (p<0.05). Maximum phenolic contents were found in the concentration of 1 µg of methanol extract and the minimum in 0.01 µg hexane extract. Maximum iron reduction power in methanol and chloroform extracts at a concentration of 1 µg and the minimum concentration of 0.01 μg of hexane extract was measured (p<0.05). The carotenoids and the chlorophyll b have the highest and lowest content, respectively (p<0.05). The study of the fatty acid composition of Dunaliella saline showed that the palmitic acid, palmitoleic acid, and alpha-linolenic acid were the highest saturated, monoenoic, and polyunsaturated fatty acids respectively. The results of this study have investigated that the concentration factor had a significant effect on the antioxidant properties of Dunaliella salina algae. The methanol extract had the best efficiency of Donalilla salina microalgae metabolite extraction.

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Melanin is known as one of the main pigment components of ink in pharaoh cuttlefish, which has a strong bond with the hydroxyl group of TiO2. The aim of this study was to determine the appropriate method for extracting melanin from the ink of pharaoh cuttlefish fish (Sepia pharaonis). Melanin was extracted using four methods i.e., NaOH and HCL, extraction using squid ink dilution, extraction using a drying ink bag, and extraction by centrifugal washing. The Radius Power method was also used to measure the regenerative power of the sample. Data analysis showed a significant difference among different extraction methods so the method of washing with deionized water and centrifuge with 66.12% and the method of washing with deionized and homogenized water with 22.42% were determined as the optimal methods. This is despite the fact that the best antioxidant performance of melanin in the washing method was observed using sodium hydroxide and hydrochloric acid and the washing method with deionized water and centrifugation. The best antioxidant performance was observed in all four methods at 1 mg/ml. According to the obtained results, among the studied methods, the method of washing with deionized water and centrifugation was determined as the best method of melanin extraction.
 

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Fish mucus layers are the main surface of exchange between fish and the environment, and they possess important biological and ecological functions. In the present study, the antioxidant activity (reducing power, total antioxidant capacity, and free radical scavenging of DPPH) and cytotoxicity (test of saltwater shrimp larvae) of four species of Solea elongate, Euryglossa orientalis, Netuma bilineata, Muraenesox cinereus were investigated. The results showed that E. orientalis fish mucus had the highest reducing power (1.6 ± 0.2), N. bilineata fish mucus had the highest total antioxidant capacity (0.93 ± 0.3) and the highest percentage of free radical scavenging DPPH (89 ± 0.2). In the cytotoxicity test, the highest mortality rate under the influence of S. elongate mucus was about 97.5 ± 2.5. The results of the present study showed that fish mucus can be introduced as a potential source of natural biological compounds with high antioxidant activity and cytotoxicity.

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Coral bleaching, loss of symbiotic algae of Symbiodinium sp. or photosynthetic microalgae pigments from their coral host have become commonplace in recent decades due to the rising of sea temperatures and changes in physicochemical factors. It is essential to study the susceptibility of corals to bleaching, the physiology of its symbiotic algae, and its capacity to cope with abiotic stress. Oxidative stress is of particular importance due to the fact that it can be caused by photosynthetic dysfunction drived by temperature and other physicochemical factors. The aim of this study was to compare the effects of physicochemical factors on the photosynthetic performance of Symbiodinium sp. symbiosis with Stichodactyla haddoni in the Persian Gulf and the Gulf of Oman. To determine whether the cultured Symbiodinium sp. has different sensitivities to oxidative stress and whether winter and summer play a role in oxidative stress and coping with it, DPPH test and Freak ion reduction method (FRAP) were used and Physicochemical factors were measured through the HQ40D prototype device. Moreover, air data (wind speed) was obtained from the website www.irimo.ir. Statistical analysis was performed through one-way analysis of variance at the level of 0.05 and heatmap analysis. The results showed that the highest antioxidant capacity was assigned to Symbiodinium sp. extract in Chabahar in winter (IC50:135.768 μgr/ml) and the lowest antioxidant capacity was allocated to Chabahar in summer (IC50:349.090 μgr/ml). Ferric ion reduction of Symbiodinium sp. extracts showed the highest inhibition compared to ascorbic acid at a concentration of 2 mg/ml (0.297) and the lowest inhibition at a concentration of 0.063 mg/ml (0.015) in Chabahar in winter.

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