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Steroids are one of the most important and abundant secondary metabolites of marine sponges. The aim of this study was to investigate the antibacterial properties of steroidal fractions derived from the Persian Gulf sponge Axinella sinoxea. Extraction was first done by Acetone and then the fractions were separated through column chromatography with silica gel. Identification of steroidal fractions were done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Then, antibacterial properties of steroids were identified and minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Two types of steroids including Stigmasta-5,24(28)-dien-3-ol,(3β-24Z) and Ergosta-5,22-dien-3-ol,(3β,22E,24S) were determined. The extracted steroids showed different results regarding the growth inhibition and bactericidal effect on Gram negative (Escherichia coli, Klebsiella pneumoniae and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria at different experimental doses. In conclusion, promising results were found regarding the antimicrobial effects of the extracted steroids of the marine sponge from Larak island A. sinoxea. These findings reveal the necessity of more comprehensive investigations for the synthesis of pharmaceutical and antibiotic materials from the  bioactive compounds.

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Squalene is an unsaturated triterpene hydrocarbon and is a precursor of steroids and cholesterol with antioxidant properties. The aim of this study was to isolate the squalene from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to investigate its antimicrobial activity. Extraction was first done by methanol 70% and then, the squalene was separated through column chromatography with silica gel. Identification of the extracted squalene was done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Antibacterial properties of the squalene were identified and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Identification of the extracted compounds by GC-MS confirmed the presence of the squalene in the shark liver. Antibacterial studies showed that the squalene inhibited the growth of Gram negative (Escherichia coli, Klebsiella pneumonia and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria. Therefore, this metabolite has the potential to be more investigated for developing new antimicrobial compounds.

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Biofloc technology has mentioned as a new tool for sustainable aquaculture development and has overcome the problems of water scarcity and discharge of aquaculture effluents to the environment. In this system, nitrogenous wastes (Ammonia and Ammonium) are simultaneously recovered by bacteria and converted into microbial proteins that can be consumed by aquatic animals. The purpose of this study was to investigate the factors affecting the production of biofloc and evaluate it for use in aquaculture. The effect of different temperature levels (24, 28, 32 °C), salinity (0, 4, 8 g/l)  ,and C/N ratio (10:1, 15:1, 20:1) which are the main key factors to the formation and function of biofloc system was evaluated by using a response surface method designing. Moreover, the influence of those factors on total ammonia nitrogen, nitrite, nitrate, floc volume, protein, and lipid content of biofloc was investigated. The results showed that the temperature had a significant effect on floc volume and protein content of biofloc (P < 0.05), but it had no significant effect on other nitrogenous compounds and lipid content (p > 0.05). The protein, lipid and moisture of biofloc particles were decreased by increasing salinity significantly (P < 0.05). Also, TAN and nitrite concentration influenced by C/N ratio inversely. According to the factors Optimization, providing 27 °C and C/N ratio of 18:1 in brackish water and 29 °C and C/N ratio of 14:1 in fresh water resulted in high quality biofloc production and control of nitrogenous wastes in water.

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Due to widespread use of nanoparticles in various fields and the possibility of entering these nanoparticles into aquatic ecosystems, it is necessary to study the effects of these nanoparticles on surrounding environment. Artemia salina nauplii as a suitable biological model in ecotoxicology were exposed to different concentrations of 0.0001, 0.001, 0.005, 0.01 and 0.1 ppm mercury ions separately and simultaneously with a constant concentration of 0.1 ppm and 1 ppm titanium dioxide nanoparticles. The mortality rate of Artemia after 48 hours and the effects of these contaminants on fatty acid profile of Artemia were investigated. Artemia mortality in co-exposure treatment showed a dual effect. The mortality in the simultaneous exposure with constant concentration of 0.1ppm titanium dioxide increased compared with separate treatment of mercury. The mortality in simultaneous treatment with constant concentration of 1ppm titanium dioxide decreased compared with the separate treatment of mercury and the effect of mercury toxicity was reduced. Also, a decrease in saturated fatty acids was observed in the simultaneous exposure of mercury and titanium dioxide nanoparticles with a constant concentration of 1ppm compared with the separate treatment of mercury. The amount of monounsaturated and polyunsaturated fatty acids in the simultaneous exposure with constant concentration of 1ppm titanium dioxide was equal to control and increased compared with separate treatment of mercury. Present findings indicate the necessity of paying more attention to the potential interactions of pollutants in aquatic ecosystems and the effects of these interactions on the bioavailability and toxicity of pollutants regarding their concentration.

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The significance of mangrove species in the world is undeniable and planting artificial mangrove forests is a desirable solution to preserve mangroves. The mangroves provide us with superior ecological services and one of their main services is the bioremediation of heavy metals. Hence, this study aimed to assess the effects of artificial mangroves of Velayat Park of Bandar Abbas on the contamination, adsorption pattern and ecological risk of heavy metals in the sediment samples. Thirty samples were collected from two paralleled sampling sections included those without mangroves and containing mangroves. Each sampling area consisted of upper, middle and lower sections. After drying samples using an oven, the dried sediments were sieved by a 63-micrometer sieve and digested by nitric and hydrochloric acid mixture. The concentration of As, Cu, Fe, Ni, Pb, V, and Zn was determined using ICP. The studied factors suggested a high level of ecological risk for as and Pb and the highest risk was observed in the samples without mangroves and a lower risk was reported for samples containing mangroves. Comparing the results with sediment quality guidelines and other studies indicated a dangerous concentration of As. Pearson correlation coefficient values exhibited that artificial mangroves have significantly affected the adsorption pattern of heavy metals (p-Value < 0.05). The principal component analysis (PCA) showed that As and Pb are dominantly derived from oil products leakages and industrial sewages while Cu, Fe, Ni, V and Zn are predominantly derived from natural and geological sources.

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The present study aimed to isolate the steroids and fatty acids from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to assess their antifungal activity. Extraction was done by methanol 70% and then, the lipids were separated through column chromatography with silica gel. Identification of the extracted lipids was done by thin layer chromatography and gas chromatography coupled with mass spectrometry. Then, antifungal activity of the steroids was investigated through determining the minimum inhibition concentration and minimum fungicidal concentration by tubular dilution method against Aspergillus fumigatus and Candida albicans. Identification of the extracted compounds by GC-MS confirmed the presence of these steroids in the shark liver. The identified steroids included compounds of Y-Sitosterol, Desmosterol and Squalene, which showed different results regarding the growth inhibition and fungicidal effects against the microorganisms at different experimental doses. Desmosterol and Squalene at minimum concentration induced the highest inhibitory effect on the fungus but Y-Sitosterol induced the highest inhibitory effect on the yeast. Squalene showed fungicidal effect only on the fungus and totally, A. fumigatus was more sensitive to the antimicrobial activity of the liver compounds than C.  albicans. In conclusion, promising results were found regarding the antimicrobial activity of the lipid compounds derived from Persian Gulf shark liver, revealing the importance of more comprehensive investigations of these natural compounds for the synthesis of biomedicines from the marine organisms.
 

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Quercetin is a flavonoid, abundantly present in plants and has gained considerable interest for its antioxidant properties.  The present study was designed to assess and compare the influence of both free and nano-encapsulated quercetin on growth indices and survival in Penaeus vannamei. The ionic gelation method was used to prepare quercetin loaded nanoparticles (Qu-ChiNPs), and their characteristics were determined using DLS method. The finding related to the characterization of Qu-ChiNPs demonstrated that hydrodynamic size and Zeta potential were 160/1 nm and 33/8 mV, respectively, and in vitro release of drug from Qu ChiNPs illustrated burst release in the initial period. For feeding trial, shrimps with an average weight of 2/27 ± 0/18 g with 5 diets including: basic diet without Qu, Qu-Chi and Chitosan nanoparticles supplement (control), supplement with 0.5 g Querectin, 0.25 g Qu-Chi, 0.5 g Qu-Chi and 0.5 g Chitosan nanoparticles per kg of diet were fed. Shrimp were randomly divided into 5 groups, with 3 replicates in each group and 50 shrimp in each replicate. After a 2-month feeding period, results showed that final weight (Wf), weight gain (WG) and mean daily weight gain (ADG) of shrimp fed Qu-Chi 0.5 g were higher than the other treatments (P˂ 0.05). However, there was no significant difference in survival rate (SR) between treatments. The results showed that the use of Qu-Chi 0.5 g in the diet can have a positive effect on growth performance and survival of Penaeus vannamei.