Effect of elevated temperature, sea water acidification, and phenanthrene on the expression of genes involved in the shell and pearl formation of economic pearl oyster (Pinctada radiata).

Our study aims to examine the effect of some stressors on the gene expression levels of shell matrix proteins in a pearl oyster. Oysters were exposed to the different combinations of the temperature, pH, and phenanthrene concentration is currently measured in the Persian Gulf and the predicted ocean warming and acidification for 28 days. The expression of all the studied genes was significantly downregulated. Time and temperature had the greatest effects on the decreases in n19 and n16 genes expression, respectively. Aspein and msi60 genes expression were highly influenced by pH. Pearlin was affected by double interaction temperature and phenanthrene. Moreover, a correlation was observed among the expression levels of studied genes. This study represents basic data on the relationship between mRNA transcription genes involved in the shell and pearl formation and climate changes in pollutant presence conditions and acclimatizing mechanism of the oyster to the future scenario as well.

Oxidative stress, genotoxic effects, and other damages caused by chronic exposure to silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs), and their mixtures in zebrafish (Danio rerio).

This study assessed the oxidative stress impacts of Ag NPs and ZnO NPs and their mixtures in zebrafish (Danio rerio). Zebrafish were exposed to sublethal concentrations of each NP and a mixture for 28 days followed by a 28-day recovery period (without NP exposure) and measurements made on hepatic levels of antioxidant enzymes (CAT, SOD, and GPx), MDA levels, expression of the genes for the Hsp70 and Hsp90, and MT, blood biochemical parameters (total protein, globulin, albumin, AST, ALT, ALP, and LDH), and genotoxicity in erythrocytes (via measurement of micronuclei (MN) and nuclear (NA) abnormalities). There was a tendency for an increase in the variation in the responses of antioxidant defense systems and there were higher MDA levels with increasing exposure concentration of Ag NPs and with increasing exposure time. Total protein, globulin, and albumin decreased during the exposure period, especially on the days of 28. Moreover, levels of AST and LDH increased significantly in the NPs co-exposure treatments, while levels of ALT and ALP significantly decreased. The highest expression levels for these genes occurred on day 14 and in the NPs co-exposure treatments. For exposure to both NPs individually and as a mixture, the frequency of MN and other NA were significantly increased (p < 0.05). During the recovery periods, most of the effects seen were reduced, most notably in the individual NPs treatments. The overall results suggest that the toxic effects of Ag NPs and ZnO NPs in combination significantly increase their toxicity in zebrafish.

Toxicity of Silver Nanoparticles in the Presence of Zinc Oxide Nanoparticles Differs for Acute and Chronic Exposures in Zebrafish.

We assessed the acute toxicity effects (96 h) of silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) and chronic (28 d) exposure to Ag NPs, including in combination with ZnO NPs. In the chronic studies, we further assessed the toxicokinetics and bioaccumulation of Ag and the resulting histopathological effects in the gill, intestine, and liver of zebrafish. Co-exposures with ZnO NPs reduced the toxicity of Ag NPs for acute (lethality) but enhanced the toxicity effects (tissue histopathology) for chronic exposures. The histological lesions for both NPs exposures in the gill included necrosis and fusion of lamellae, for the intestine necrosis and degeneration, and in the liver, mainly necrosis. The severity of the histological lesions induced by the Ag NPs was related to the amount of accumulated Ag in the zebrafish organs. The Ag accumulation in different organs was higher in the presence of ZnO NPs in the order of the gill > intestine > liver. Depuration kinetics illustrated the lowest half-life for Ag occurred in the gill and for the combined exposure of Ag with ZnO NPs. Our findings illustrate that in addition to tissue, time, and exposure concentration dependencies, the Ag NPs toxicity can also be influenced by the co-exposure to other NPs (here ZnO NPs), emphasizing the need for more combination exposure effects studies for NPs to more fully understand their potential environmental health risks.

Efficient removal of cytotoxic drugs from wastewater by single-stage combined photocatalysis-algae treatment process.

In this study, the efficiency of a single-stage combined photocatalysis-algae treatment process in the removal of the anticancer drug, flutamide (FLU), from aqueous solution has been evaluated. The removal abilities of the individual blue-green alga (Anabaena sp.), nano-sized MoS2 photocatalyst under visible light irradiation, and combined photocatalysis-algal treatment process were investigated. Using response surface optimization technique, 85.1% of the FLU removal was achieved at the optimum conditions of pH 7.0, nanophotocatalyst dose of 15.23 mg and 12.12 mL of the alga in 30 min. Compared to the individual biological and chemical treatment methods, a higher FLU removal efficiency was obtained at a shorter reaction time by using the combined treatment system. Kinetics study showed that FLU removal by the algal treatment, photocatalysis, and the combined processes followed the modified Freundlich, pseudo-first-order, and nonlinear sigmoidal kinetic models, respectively. The results indicate that a synergistic effect appears when algal treatment process and photocatalysis are performed simultaneously. The novel combined system is a low-cost and efficient microalgae-based technology for the removal of cytotoxic compounds from wastewaters.

Toxicological effects of Ag2O and Ag2CO3 doped TiO2 nanoparticles and pure TiO2 particles on zebrafish (Danio rerio).

In this study, the toxic effects of silver oxide and silver carbonate doped TiO2 nanoparticles (Ag2O-TiO2 NPs and Ag2CO3-TiO2NPs), TiO2 nanoparticles (TiO2 NPs), and bulk TiO2 on gene expression, lipid peroxidation, genotoxicity, and histological alterations in zebrafish (Danio rerio) was assessed. The physicochemical properties of the synthesized nanoparticles were evaluated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), diffuse reflectance spectroscopy (DRS), dynamic light scattering (DLS), and Zeta potential analyses. TiO2NPs after doping with Ag showed shift to higher wavelengths and decrease of band gap energy. Also, remarkable reduction in the size of Ag-doped TiO2NPs in comparison with the TiO2 NPs was observed. According to our results, acute toxicity increased in the order of bulk TiO2 < TiO2 NPs < Ag2O-TiO2NPs < Ag2CO3-TiO2NPs, respectively. Results of sub-lethal experiments after 30 days of exposure, showed higher expression of Gpx, Hsp70, Ucp-2, and Bax genes, and lower expression of Bcl-2 gene in Ag-doped TiO2NPs than pure TiO2 particles (TiO2 NPs and bulk TiO2) treatments (p < 0.05). However, the mRNA levels of SOD and CAT genes were significantly higher in pure TiO2 particles than doped TiO2NPs (p < 0.05). Moreover, levels of malondialdehyde, abnormalities of peripheral blood cells and severity of histological lesions in liver, gill, intestine and kidney tissues were more evident in Ag-dopedTiO2 NPs than pure TiO2 particles. It can be concluded that Ag doping of TiO2 NPs significantly increased their toxicity and resulted in more histological lesions, apoptosis and oxidative stress than pure TiO2 particles in adult zebrafish.

Fe3O4/Ag nanocomposite biosynthesised using Spirulina platensis extract and its enhanced anticancer efficiency.

In this work, the authors investigated the apoptotic activities of Fe3O4/Ag nanocomposite biosynthesised by Spirulina platensis extract against MCF-7 (human breast cancer cells). The physico-chemical properties of prepared Fe3O4/Ag nanocomposite were studied by different spectroscopic methods. To evaluate the in vitro cytotoxic effect, MCF-7 cells were treated with different concentrations of Fe3O4/Ag nanocomposite and examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Moreover, apoptotic effects were also studied by Hoechst 33258 staining, caspase 3 activation assays, and annexin V-fluorescein isothiocyanate (FITC) and propidium iodide staining. Microscopic observations of Fe3O4/Ag nanocomposites indicated approximately spherical shape and small particles in the size range of about 30-50 nm. The MTT assay result revealed that the Fe3O4/Ag nanocomposite causes a dose-dependent cell proliferation reduction in MCF-7 cells (IC50 = 135 µg/ml). Regarding to the Annexin V/PI staining result, the increase percentage of apoptotic cells (28.09%) was detected as compared to untreated cells. According to the caspase assay, Fe3O4/Ag nanocomposite enhances caspase 3 level. Furthermore, in vitro anti-cancer activity of the nanocomposite was performed by Hoechst 33258 staining method. The proposed data suggest that Fe3O4/Ag nanocomposite may be an effective agent for the inhibition of breast cancer cells at in vitro level.

Biosynthesis of Fe3O4@Ag Nanocomposite and Evaluation of Its Performance on Expression of norA and norB Efflux Pump Genes in Ciprofloxacin-Resistant Staphylococcus aureus.

At present, the universal health problem with Staphylococcus aureus is the emergence of multidrug-resistant strains due to the overuse of antibiotics. Drug extrusion through efflux pumps is one of the bacterial mechanisms to neutralize the bactericidal effect of antibiotics. The antibacterial activity of silver nanoparticle as well as Fe3O4 nanoparticle had been previously studied and widely described. Today, the development of green methods for nanomaterial synthesis is an important aspect of research in the field of nanotechnology. Here, we report the biosynthesis and characterization of Fe3O4@Ag nanocomposite by Spirulina platensis cyanobacterium and it impacts on the expression of efflux pump genes in ciprofloxacin-resistant S. aureus (CRSA). The physical properties of biosynthesized nanocomposite measured and confirmed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning and transmission electron microscopy. The minimum inhibitory concentration (MIC) of ciprofloxacin in CRSA strains was determined in the presence of Fe3O4@Ag nanoparticles by broth microdilution method. The effect of Fe3O4@Ag nanocomposite on the expression of norA and norB genes was evaluated by real-time PCR. The physical analysis confirmed well-dispersed, highly stable, and mostly spherical Fe3O4/Ag NPs with the average size of 30-68 nm. The results of antibacterial tests showed the synergistic effects of nanocomposite and antibiotics in MIC reduction. Additionally, in the presence of Fe3O4@Ag nanocomposite, the expression of norA and norB genes was decreased more than twofold compared to control. In conclusion, the Fe3O4/Ag nanocomposite can use as an effective inhibitor of antibiotic resistance in medicine.

Antimicrobial activity of methanolic extracts of Sambucus ebulus and Urtica dioica against clinical isolates of methicillin resistant Staphylococcus aureus.

BACKGROUND: Increase in the emergence of drug -resistant pathogens led to the development of natural antimicrobials. In this study the antimicrobial effect of methanolic extracts of Sambucus ebulus and Urtica dioica on 16 skin and wound infections isolates of methicillin resistant S. aureus have been studied. MATERIAL AND METHODS: Solvent extraction procedure was done using soxhlet apparatus for extracting antimicrobial agents from freeze dried plants. Antibacterial activity was measured using agar well diffusion method. RESULTS: The MIC of Sambucus ebulus and Urtica dioica extracts against the standard strain of S. aureus ATCC 6538 were determined using the micro dilution method at 15 mg and 20 mg respectively. All the test bacteria were found sensitive to the Sambucus ebulus extract and only one isolate was resistant to Urtica dioica extract. CONCLUSION: Extracts of Sambucus ebulus and Urtica dioica possess antibacterial potency against MRSA isolates and may be used as a natural antiseptics and antimicrobial agents in medicine.