Medicinal mushrooms have been used for centuries against cancer and infectious diseases. These positive biological effects of mushrooms are due in part to the indirect action of stimulating immune cells. The objective of the current study is to investigate the possible immunomodulatory effects of mushroom polysaccharides on NK cells against different cancer cells. In this current study, fruiting bodies isolated from cultured Pleurotus ostreatus were extracted and partially purified using DEAE ion-exchange chromatography. The activation action of the collected fractions on Natural Killer cells was quantified against three different cancer cell lines in the presence or absence of human recombinant IL2 using three different activation and co-culture conditions. The possible modes of action of mushroom polysaccharides against cancer cells were evaluated at the cellular and molecular levels. Our results indicate that P. ostreatus polysaccharides induced NK-cells cytotoxic effects against lung and breast cancer cells with the largest effect being against breast cancer cells (81.2%). NK cells activation for cytokine secretion was associated with upregulation of KIR2DL genes while the cytotoxic activation effect of NK cells against cancer cells correlated with NKG2D upregulation and induction of IFNγ and NO production. These cytotoxic effects were enhanced in the presence of IL2. Analysis of the most active partially purified fraction indicates that it is predominantly composed of glucans. These results indicate bioactive 6-linked glucans present in P. ostreatus extracts activate NK-cell cytotoxicity via regulation of activation and induction of IFNγ and NO. These studies establish a positive role for bioactive P. ostreatus polysaccharides in NK-cells activation and induction of an innate immune response against breast and lung cancer cells.
Research into the molecular mechanisms of the switch from highly motile to biofilm forming Pseudomonas fluorescens bacteria recently uncovered a role of inorganic phosphate as an important environmental regulatory factor to control c-di-GMP levels in the cell. In this study we present evidence that in the opportunistic pathogen P. aeruginosa the Pho regulon inhibits biofilm formation and is required for the repression of the type three secretion system. We furthermore identified an EAL domain protein as a downstream effector of the Pho regulon, which at least partially mediated the observed inhibition. Interestingly, inhibition of the P. aeruginosa virulence phenotype was Pho regulon-dependent in both a PA14 and a PAO1 strain background; however, in PA14 this inhibition was independent on the availability of inorganic phosphate, whereas in PAO1 phosphate enhanced biofilm formation independently of the inhibitory activity of the Pho regulon. These results clearly show that the Pho regulon contributes to the expression of the virulence phenotype in P. aeruginosa and add even more complexity to the strain-specific regulation of bacterial behaviour by environmental cues.
A total of twenty bacterial cultures were isolated from hydrocarbon contaminated soil. Of the 20 isolates, RAM03, RAM06, RAM13, and RAM17 were specifically chosen based on their relatively higher growth on salt medium amended with 4 % crude oil, emulsion index, surface tension, and degradation percentage. These bacterial cultures had 16S rRNA gene sequences that were most similar to Ochrobactrum cytisi (RAM03), Ochrobactrum anthropi (RAM06 and RAM17), and Sinorhizobium meliloti (RAM13) with 96 %, 100 % and 99 %, and 99 % similarity. The tested strains revealed a promising potential for bioremediation of petroleum oil contamination as they could degrade >93 % and 54 % of total petroleum hydrocarbons (TPHs) in a liquid medium and soil amended with 4 % crude oil, respectively, after 30 day incubation. These bacteria could effectively remove both aliphatic and aromatic petroleum hydrocarbons. In conclusion, these strains could be considered as good prospects for their application in bioremediation of hydrocarbon contaminated environment.
Small-colony variants (SCVs) of Pseudomonas aeruginosa are often found in chronically infected airways of patients suffering from cystic fibrosis. These slow-growing morphological variants have been associated with persistent and antibiotic-resistant infections. Nevertheless, the behavior of SCVs under varied availability of O₂ and iron, two key variables relevant to the lung environment of CF patients and pathogenicity of P. aeruginosa, has not been systematically studied so far. In this work, the effects of O₂ and iron were comparatively studied for a CF P. aeruginosa wild type (WT) strain and its SCV phenotype in a real-time controlled cultivation system. Significant differences in the behavior of these strains were observed and quantified. In general, SCV exhibited a higher fitness than the WT toward aerobic conditions. Under iron rich condition, and despite less release of total extracellular proteins, absence of flagellin and lower siderophore production, the SCV cells grown at fully aerobic conditions showed a higher specific growth rate and a significantly higher cytotoxicity in comparison with the WT cells. The strains behaved also differently towards iron limitation. The phenomena of limited O₂ transfer from the gas to the liquid phase and enhancement of formation of virulence factors under conditions of iron limitation were much more profound in the SCV culture than in the WT culture. These results have important implications for better understanding the pathogenicity of P. aeruginosa and its small-colony variants.
The public concern for industrial pollution is urging for an economical solution to remove industrial effluent that increases the risk of human cancers. Currently, there are a few successful techniques implemented for dye removal; however, little has been done in the field of using reusable biological material extracted from waste. We propose a new procedure to fabricate biocompatible magnetic collagen for dye removal. Our study was conducted on crystal violet (CV) removal from industrial effluent using fish scales collagen. In this study, removal of dye by adsorption on various types of collagen was studied using soft, coarse and magnetic collagen nanocomposite. The magnetic collagen nanocomposite was synthesized by coprecipitation method followed by mixing of iron nanoparticles with collagen. Characterization of the prepared materials was performed using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Soft collagen, coarse collagen and magnetic collagen nanocomposite were proved to adsorb crystal violet dye at concentrations up to 1000 ppm. Uptake capacity was 92% at 100 ppm of CV while cytotoxicity was reduced to 15%. The ability of collagen and magnetic collagen nanocomposite to adsorb the dye and thus reducing the polluted water cytotoxicity, as well as accumulating under the action of the magnetic field was proved experimentally.
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