The physicochemical, antioxidant, hypoglycemic and prebiotic properties of γ-irradiated polysaccharides extracted from Lentinula edodes

In this study, the influence of γ-irradiation with different dose (0, 4, 8, and 16 kGy) on chemical composition, physicochemical features and bioactivities of polysaccharides extracted from Lentinula edodes (LEP) were investigated. The carbohydrate content (from 59.47 to 70.96%), the solubility, the ⋅OH and DPPH scavenging ability of LEP increased with the increased γ-irradiation dose, while the protein content, the weight-average and number-average molecular weight of LEP were significantly decreased with the increased γ-irradiation dose. Moreover, γ-irradiation treatment caused LEP color changes and surface topography destroyed. γ-Irradiated LEP showed higher hypoglycemic activities in vitro than that of non-irradiated LEP. Moreover, γ-irradiated LEP had better proliferation promoting effects on Lactobacillus rhamnosus and L. plantarum. These results showed that γ-irradiation treatment changes the physicochemical features of LEP, thus affects its antioxidant, hypoglycemic and prebiotic properties, which suggests that γ-irradiated LEP has potential application in the pharmaceutical industries and functional foods.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01234-5.

Influence of γ-irradiation on physicochemical, functional, proximate, and antioxidant characteristics of pigmented rice flours

In recent years, food irradiation using γ-rays is one of the most valuable practices for insect disinfestation in rice grains for extended shelf life. In this study, flours from four pigmented rice cultivars were exposed to γ-irradiation using 60Co at different doses (0, 5, 10, and 15 kGy). The impact of γ-irradiation on the physico-chemical, functional, and morphological characteristics of pigmented rice flours were analyzed. Results revealed that reduction in amylose content, pH, bulk density, tapped density, and syneresis, while solubility, water absorption capacity, and swelling power values increased significantly (p < 0.05). Pasting characteristics of pigmented rice flours also reduced after exposure to γ-irradiation. Morphological features of pigmented rice flour granules revealed no evidence of physical destruction after irradiation except for black kavuni flour. The structural analysis by FTIR confirms no effect of γ-irradiation on pigmented rice flours. Overall, the study revealed that irradiated pigmented rice flours with enhanced functional properties of less than 10 kGy can be effectively used in the development of value-added rice-based food products considering all the beneficial and safety aspects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05709-z.

Boosting the Anticancer Activity of Aspergillus flavus "endophyte of Jojoba" Taxol via Conjugation with Gold Nanoparticles Mediated by γ-Irradiation

Taxol production by fungi is one of the promising alternative approaches, regarding to the natural and semisynthetic sources; however, the lower yield and rapid loss of Taxol productivity by fungi are the major challenges that halt their further industrial implementation. Thus, searching for fungal isolates with affordable Taxol-production stability, in addition to enhance its anticancer activity via conjugation with gold nanoparticles, is the main objectives of this study. Twenty-four endophytic fungal isolates were recovered from the barks, twigs, and leaves of jojoba plant, among these fungi, Aspergillus flavus MW485934.1 was the most potent Taxol producer (88.6 µg/l). The chemical identity of the extracted Taxol of A. flavus was verified by the TLC, HPLC, HNMR, and FTIR analyses. The yield of Taxol produced by A. flavus was optimized by the response surface methodology (RSM) using Plackett-Burman (PBD) and faced central composite designs (FCCD). The yield of Taxol by A. flavus was increased by about 3.2 folds comparing to the control cultures (from 96.5 into 302.7 µg/l). The highest Taxol yield by was obtained growing A. flavus on a modified malt extract medium (g/l) (malt extract 20.0, peptone 2.0, sucrose 20.0, soytone 2.0, cysteine 0.5, glutamine 0.5, and beef extract 1.0 adjusted to pH 6.0) and incubated at 30 °C for 16 days. From the FCCD design, the significant variables affecting Taxol production by A. flavus were cysteine, pH, and incubation time. Upon A. flavus γ-irradiation at 1.0 kGy, the Taxol yield was increased by about 1.25 fold (375.9 µg/l). To boost its anticancer activity, the purified Taxol was conjugated with gold nanoparticles (AuNPs) mediated by γ-rays irradiation (0.5 kGy), and the physicochemical properties of Taxol-AuNPs composite were evaluated by UV-Vis, DLS, XRD, and TEM analyses. The IC₅₀ values of the native-Taxol and Taxol-AuNPs conjugates towards HEPG-2 cells were 4.06 and 2.1 µg/ml, while the IC₅₀ values against MCF-7 were 6.07 and 3.3 µg/ml, respectively. Thus, the anticancer activity of Taxol-AuNPs composite was increased by 2 folds comparing to the native Taxol towards HEPG-2 and MCF-7 cell lines. Also, the antimicrobial activity of Taxol against the multidrug resistant bacteria was dramatically increased upon conjugation with AuNPs comparing to authentic AuNPs and Taxol, ensuring the higher solubility, targetability, and efficiency of Taxol upon AuNPs conjugation.

The efficacy of bone marrow-derived mesenchymal stem cells and/or erythropoietin in ameliorating kidney damage in gamma irradiated rats: Role of non-hematopoietic erythropoietin anti-apoptotic signaling

Radiation-induced multiple organ injury, including γ-radiation nephropathy, is the most common. Even with dose fractionation strategy, residual late side effects are inevitable. Bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation and erythropoietin (EPO) have shown to be effective in treating chronic kidney disease and associated anemia. This study aimed to evaluate the effect of BM-MSCs and/or EPO in fractionated γ-irradiation induced kidney damage in rats. Adult male Wistar rats were randomized into 2 groups; normal and 8 Gy (fractionated dose of 2 Gy for 4 days) γ-irradiated rats. Animal from both groups were subdivided to receive the following treatments: BM-MSCs (1 × 10⁶ cells/rat, i.v - once), EPO (100 IU/kg, i.p - every other day for 30 days) or their combined treatment (BM-MSCs and EPO). γ-Irradiated rats showed a noticeable elevation in serum urea and creatinine, kidney malondialdehyde (MDA) and caspase 3 activity. They also revealed significant drop in kidney glutathione (GSH) and Bcl2 protein contents. Conspicuously, they revealed down-regulation of renal EPO signaling (EPO, EPOR, pJAK2, pPI3K and pAkt). Conversely, groups treated with BM-MSCs and/or EPO revealed significant modulation in most tested parameters and appeared to be effective in minimizing the hazard effects of radiation. In conclusion, BM-MSCs and/or EPO exhibited therapeutic potentials against nephrotoxicity induced by fractionated dose of γ-irradiation. An effect mediated by antioxidant and non-hematopoietic EPO downstream anti-apoptotic signaling (PI3K/Akt) pathway. EPO potentiate the repair capabilities of BM-MSCs making this combined treatment a promising therapeutic strategy to overcome radiotherapy-induced kidney damage.

Assessment of absorbed dose of gamma rays using the simultaneous determination of inactive hemoglobin derivatives as a biological dosimeter

Biological dosimetry based on sulfhemoglobin (SHb), methemoglobin (MetHb), and carboxyhemoglobin (HbCO) levels was evaluated. SHb, MetHb and HbCO levels were estimated in erythrocytes of mice irradiated by γ rays from a ⁶⁰Co source using the method of multi-component spectrophotometric analysis developed recently. In this method, absorption measurements of diluted aqueous Hb-solution were made at λ = 500, 569, 577 and 620 nm, and using the mathematical formulas based on multi-component spectrophotometric analysis and the mathematical Gaussian elimination method for matrix calculation, the concentrations of various Hb-derivatives and total Hb in mice blood were estimated. The dose range of γ rays was from 0.5 to 8 Gy and the dose rate was 0.5 Gy min^-1. Among all Hb-derivatives, MetHb, SHb and HbCO demonstrated an unambiguous dose-dependent response. For SHb and MetHb, the detection limits were about 0.5 Gy and 1 Gy, respectively. After irradiation, high levels of MetHb, SHb and HbCO persisted for at least 10 days, and the maximal increase of MetHb, SHb and HbCO occurred up to 24 h following γ irradiation. The use of this "MetHb + SHb + HbCO"-derivatives-based absorbed dose relationship showed a high accuracy. It is concluded that simultaneous determination of MetHb, SHb and HbCO, by multi-component spectrophotometry provides a quick, simple, sensitive, accurate, stable and inexpensive biological indicator for the early assessment of the absorbed dose in mice.

Modulatory effect of zingerone against cisplatin or γ-irradiation induced hepatotoxicity by molecular targeting regulation

Zingerone (ZO) is an ingredient of ginger (Zingiber officinale) which has different pharmacological properties. The objective of this research was to evaluate the protective effect of ZO against Cisplatin (Cis) or γ-Irradiation (IR)-induced hepatotoxicity in rats. ZO was given orally for consecutive 14 days prior to the treatment with Cis or exposure to IR at 15th day. Animals were sacrificed at the 23rd day. Cis or IR induced a marked increase in MAPK signal transduction as evidenced by increased p38 MAPK, JNK and ErK1/2. CYP2E1 and NADPH oxidase were significantly up-regulated. Inflammatory markers (TLR4, iNOS, COX-2 and MPO) and liver enzymes (AST, ALT and ALP) activities were also increased. Administration of ZO significantly ameliorated the above mentioned parameters.

Outlook for coeliac disease patients: towards bread wheat with hypoimmunogenic gluten by gene editing of α- and γ-gliadin gene families

BACKGROUND

Wheat grains contain gluten proteins, which harbour immunogenic epitopes that trigger Coeliac disease in 1-2% of the human population. Wheat varieties or accessions containing only safe gluten have not been identified and conventional breeding alone struggles to achieve such a goal, as the epitopes occur in gluten proteins encoded by five multigene families, these genes are partly located in tandem arrays, and bread wheat is allohexaploid. Gluten immunogenicity can be reduced by modification or deletion of epitopes. Mutagenesis technologies, including CRISPR/Cas9, provide a route to obtain bread wheat containing gluten proteins with fewer immunogenic epitopes.

RESULTS

In this study, we analysed the genetic diversity of over 600 α- and γ-gliadin gene sequences to design six sgRNA sequences on relatively conserved domains that we identified near coeliac disease epitopes. They were combined in four CRISPR/Cas9 constructs to target the α- or γ-gliadins, or both simultaneously, in the hexaploid bread wheat cultivar Fielder. We compared the results with those obtained with random mutagenesis in cultivar Paragon by γ-irradiation. For this, Acid-PAGE was used to identify T1 grains with altered gliadin protein profiles compared to the wild-type endosperm. We first optimised the interpretation of Acid-PAGE gels using Chinese Spring deletion lines. We then analysed the changes generated in 360 Paragon γ-irradiated lines and in 117 Fielder CRISPR/Cas9 lines. Similar gliadin profile alterations, with missing protein bands, could be observed in grains produced by both methods.

CONCLUSIONS

The results demonstrate the feasibility and efficacy of using CRISPR/Cas9 to simultaneously edit multiple genes in the large α- and γ-gliadin gene families in polyploid bread wheat. Additional methods, generating genomics and proteomics data, will be necessary to determine the exact nature of the mutations generated with both methods.

Effect of γ-irradiation on physico-chemical and antioxidant properties of galactan exopolysaccharide from Weissella confusa KR780676

Exopolysaccharide (EPS) produced by Weissella confusa KR780676 from an Indian fermented food (Idli) has been characterized as galactan in earlier report. In this study, the galactan EPS was irradiated at different doses (0, 4, 8, and 16 kGy) using ⁶⁰Co as γ-source and effect of γ-irradiation on physico-chemical and antioxidant potential of galactan EPS was studied. Color and flow properties showed moderate change after the γ-irradiation treatment. Particle size analysis and scanning electron microscopy exhibited significant breakdown of the EPS particles into smaller average hydrodynamic diameter size from 495.54 to 198.44 nm with increasing irradiation doses. Overall, pH showed decrease, while the water activity showed an increasing trend with the increasing irradiation dose. No significant effect was observed in the functional groups of EPS as revealed in the FT-IR spectroscopic analysis. After the treatment, semi-crystalline nature of the EPS changed to amorphous as shown in XRD analysis due to the breakdown. Antioxidant activities of galactan EPS increased marginally after the treatment. However, hydroxyl radical scavenging activity increased significantly from 48 to 67%. Changes in physico-chemical and antioxidant properties of galactan EPS with γ-irradiation treatment altered the functional properties of EPS positively, making it more suitable for wider application in the food industry.

Taurine provides a time-dependent amelioration of the brain damage induced by γ-irradiation in rats

Exposure to ionizing radiation (IR) is inevitable since over 80% of total average exposure comes from natural sources. Brain is vulnerable to the deleterious effects of IR. Therefore, scientists paid attention in identifying novel compounds to protect against radiation-induced brain injury. Adult male albino rats weighing 120-150 g were divided into five groups, 18 rats each. Group 1 served as control, group 2 received an oral daily dose of taurine (500 mg/kg) for 2 weeks. Group 3 was exposed to a whole body single dose of γ-irradiation (6 Gy). Groups 4 and 5 received taurine before and after γ-irradiation, respectively. Six rats from each group were sacrificed after 1, 2 or 3 weeks. Throughout the 3 weeks studied, there were significant increases in MDA, NO, TNF-α levels, and Cytochrome-c and activities of Caspases -9 and -3 and significant decreases in GSH, SOD, CAT and GPx in the irradiated group when compared with the relevant control. Cerebral cortex of irradiated rats showed vacuolization and nuclear pyknosis in the neuronal cells and focal gliosis. Taurine administration pre- or post-irradiation significantly ameliorated all these previous effects. Taurine had antioxidant, anti-inflammatory, and anti-apoptotic effects and ameliorated the histopathological changes in brain in a time-dependent mode.

Effect of γ-irradiation on optical properties of Eu2 O3 -doped polystyrene polymer films

In the present study, europium (III) oxide (Eu₂ O₃ )-doped polystyrene (PS) polymer films were synthesized using a solution-casting technique for different filler levels. These films were irradiated with 5, 25 and 50 kGy γ doses and characterized using various techniques, viz. X-ray diffraction (XRD), and UV-visible and photoluminescence (PL) spectroscopies as a function of composition level and radiation dose. The UV-visible spectra indicated a decrease in the optical direct band gap of composite films with increasing concentrations of dopant and radiation dose. The band gaps of composites obtained using Tauc's equation were found to be 4.38, 4.37, 4.36 and 4.34 eV for 0, 1, 3 and 5% Eu₂ O₃ -doped PS respectively, while the band gaps of 5% Eu₂ O₃ -doped PS polymer films irradiated with 5, 25 and 50 kGy were found to be 4.30, 4.26 and 4.21 eV, respectively. Photoluminescence (PL) emission spectra showed the characteristic peaks of Eu³⁺ at 595 nm, 612 nm and 617 nm with an excitation wavelength of 247 nm. The intensity of characteristic peaks of Eu³⁺ was observed to increase with increasing filler concentration, while it was found to decrease with increasing radiation dose. The polymer under study may be useful in accidental dosimetry. As photoluminescence studies are carried out after a gap of 200 h from irradiation and PL emission of γ-irradiated polymer yielded 10 times emission when compared with non-irradiated polymer.

Reconciliation of pH, conductivity, total organic carbon with carboxylic acids detected by ion chromatography in solution after contact with multilayer films after γ-irradiation

The impact of γ-irradiation on polymers in multilayer films was studied by means of the study of the diffusion and release (spontaneous migration of the molecules from the container into the product) of chemical species in aqueous solution. A series of different measurements have been performed: pH, conductivity, total organic carbon (TOC) and ion chromatography (IC). Their evolution according to γ-irradiation dose was studied. More several rinsings made over several months allowed to quantify well the impact of the irradiation on these polymers. The samples are irradiated at several γ-doses, up to 270 kGy, and compared with a non-irradiated sample used as reference. It shows that quantity of generated carboxylic acids depends on the film material (PE/EVOH/PE and EVA/EVOH/EVA) and increases with γ-dose.

A comparative study on the radioprotective potential of the polyphenolic glycoconjugates from medicinal plants of Rosaceae and Asteraceae families versus their aglycones

Radioprotective potential of the polyphenolic glycoconjugates, isolated from flowers of Sanguisorba officinalis L. (So) and Erigeron canadensis L. (Ec), and from leaves of Fragaria vesca L. (Fv) and Rubus plicatus Whe. Et N. E. (Rp) as well as their aglycones (SoA, EcA, FvA and RpA, respectively), against γ-radiation-induced lipid peroxidation in human plasma and DNA damage in lymphocytes, were investigated in vitro. These properties were assessed by measuring the concentration of thiobarbituric acid reactive substances (TBARS) and using the alkaline comet assay, and were compared to the protective effects of rutin (R) and quercetin (Q). Cytotoxicity of the glycoconjugates/aglycones towards L929 mouse fibroblasts and human lymphocytes were also measured. Plant products from S. officinalis, similar to Q, were able to reduce the most radiation-induced lipid peroxidation as well as DNA damage and extent of oxidative damage to the DNA basis. Contrary to the pure flavonoids, where Q was shown to be significantly more effective than its glycoside R, the results did not show more benefit with application of SoA/EcA over So/Ec in terms of lipid peroxidation inhibition. Moreover, glycoconjugates Ec and So showed much higher capacity in protecting lymphocytes against radiation-induced genotoxicity which may suggest that between the polyphenolic and polysaccharide parts exist some synergistic effects. There were no significant differences between Fv versus FvA or Rp versus RpA in terms of the provided radioprotection. Summarizing, plant glycoconjugates isolated by the multi-step method offered sufficient radioprotection. In addition, they possess many advantages, compared to the synthetic polyphenolic compounds or the plant extracts, such as water-solubility and minor toxicity.

One-shot LC-MS/MS analysis of post-translational modifications including oxidation and deamidation of rat lens α- and β-crystallins induced by γ-irradiation

The eye lens is a transparent organ that functions to focus light and images on the retina. The transparency and high refraction of the lens are maintained by the function of α-, β-, and γ-crystallins. These long-lived proteins are subject to various post-translational modifications, such as oxidation, deamidation, truncation and isomerization, which occur gradually during the aging process. Such modifications, which are generated by UV light and oxidative stress, decrease crystallin solubility and lens transparency, and ultimately lead to the development of age-related cataracts. Here, we irradiated young rat lenses with γ-rays (5-500 Gy) and extracted the water-soluble (WS) and water-insoluble (WI) protein fractions. The WS and WI lens proteins were digested with trypsin, and the resulting peptides were analyzed by one-shot LC-MS/MS to determine the specific sites of oxidation of methionine and tryptophan, deamidation sites of asparagine and glutamine, and isomerization of aspartyl in rat α- and β-crystallins in the WS and WI fractions. Oxidation and deamidation occurred in several crystallins after irradiation at more than, respectively, 50 and 5 Gy; however, isomerization did not occur in any crystallin even after exposure to 500 Gy of irradiation. The number of oxidation and deamidation sites was much higher in the WI than in the WS fraction. Furthermore, the oxidation and deamidation sites in rat crystallins resemble those reported in crystallins from human age-related cataracts. Thus, this study on post-translational modifications of crystallins induced by ionizing irradiation may provide useful information relevant to the formation of human age-related cataracts.

The C-Circle Assay for alternative-lengthening-of-telomeres activity

The C-Circle Assay has satisfied the need for a rapid, robust and quantitative ALT assay that responds quickly to changes in ALT activity. The C-Circle Assay involves (i) extraction or simple preparation (Quick C-Circle Preparation) of the cell's DNA, which includes C-Circles (ii) amplification of the self-primed C-Circles with a rolling circle amplification reaction and (iii) sequence specific detection of the amplification products by native telomeric DNA dot blot or telomeric qPCR. Here we detail the protocols and considerations required to perform the C-Circle Assay and its controls, which include exonuclease removal of linear telomeric DNA, production of the synthetic C-Circle C96 and modulation of ALT activity by γ-irradiation.

Effects of γ-irradiation of original and organic matter-amended soils on the sorption of triclosan and diuron from aqueous solutions

Soil γ-irradiation is a well-known method of inhibiting microbial activity in studies of the soil sorption of organic compounds. However, few studies have addressed the possible effect of γ-irradiation on the sorptive ability of soils enriched with different types of organic matter (OM). The objective of this study was to probe the effect of soil γ-irradiation on organic compound-soil interactions in two different situations representing adding OM to soils through land disposal of (a) OM-rich sewage sludge-originating biosolids and (b) olive mill wastewater (OMW). Both situations describe frequent environmental and agricultural scenarios. Comparisons of aqueous sorption on cobalt-60 γ-irradiated and non-irradiated soil sorbents were carried out for (a) triclosan (in a series of three soils and their lab-incubated mixtures with three different types of biosolids), and (b) the pesticide diuron (in two different untreated and OMW-affected soils). In each case, sodium azide was used as a biocide. Soil γ-irradiation affected the sorption of organic compounds by a factor generally not exceeding 2-3. Specifically, for triclosan, the sorbed concentration ratio between irradiated and non-irradiated soils when averaged over all the soil samples was 0.94. No significant effects of γ-irradiation on soil organic carbon or total nitrogen contents were observed. The effect of γ-irradiation on a soil sorbent may be less important when a rough estimate of a soil sorption coefficient of an organic compound is needed. However, it may need to be taken into account in mechanistic sorption studies, specifically, when the shape of sorption isotherms is of interest.

Effects of γ-Irradiation on the Molecular Structures and Functions of Human Serum Albumin

In this paper, we use spectroscopic methods (fluorescence spectroscopy, UV absorption spectroscopy, and circular dichroism (CD) spectroscopy) to elucidate the effects of reactive oxygen species generated by γ-irradiation on the molecular properties of human serum albumin (HSA). The results of fluorescence spectroscopy indicated that oxidation by γ-irradiation can lead to conformational changes of HSA. Data of CD spectra suggested that with the increase of radiation dose the percentage of α-helix in HSA has decreased. The determination of protein hydrophobicity showed that the effective hydrophobicity of HSA decreased up to 62% compared to the native HSA solution due to the exposure to the γ-irradiation. Furthermore, small changes in the esterase-like activity of HSA were introduced because of oxidation. The content of bityrosine increased markedly, suggesting that the oxidized HSA was aggregated. Moreover, there was no obvious change in the molecular properties of HSA with low γ-irradiation dose. Changes happened when the irradiation dose exceeded 200 Gy.

Cytokine expression and ultrastructural alterations in fresh-frozen, freeze-dried and γ-irradiated human amniotic membranes

The aim of this work was to compare the effects on human amniotic membrane of freeze-drying and γ-irradiation at doses of 10, 20 and 30 kGy, with freezing. For this purpose, nine cytokines (interleukin 10, platelet-derived growth factor-AA, platelet-derived growth factor-BB, basic fibroblast growth factor, epidermal growth factor, transforming growth factor beta 1, and tissue inhibitors of metalloproteinase-1, -2, and -4) were titrated in 5 different preparations for each of 3 amniotic membranes included in the study. In addition, the extracellular matrix structure of each sample was assessed by transmission electron microscopy. While freeze-drying did not seem to affect the biological structure or cytokine content of the different amniotic membrane samples, γ-irradiation led to a significant decrease in the tissue inhibitors of metalloproteinase-4, basic fibroblast growth factor and epidermal growth factor, and induced structural damage to the epithelium, basement membrane and lamina densa. The higher the irradiation dose the more severe the damage to the amniotic membrane structure. In conclusion, the Authors recommend processing amniotic membrane under sterile conditions to guarantee safety at every step rather than final sterilization with γ-irradiation, thereby avoiding alteration to the biological characteristics of the amniotic membrane.

Hepatoprotective effect of grape seed oil against carbon tetrachloride induced oxidative stress in liver of γ-irradiated rat

Carbon tetrachloride (CCl4) and ionizing radiation are well known environmental pollutants that generate free radicals and induce oxidative stress. The liver is the primary and major target organ responsible for the metabolism of drugs, toxic chemicals and affected by irradiation. This study investigated the effect of grape seed oil (GSO) on acute liver injury induced by carbon tetrachloride (CCl4) in γ-irradiated rats (7Gy). CCl4-intoxicated rats exhibited an elevation of ALT, AST activities, IL-6 and TNF-α level in the serum. Further, the levels of MDA, NO, NF-κB and the gene expression of CYP2E1, iNOS and Caspase-3 were increased, and SOD, CAT, GSH-Px, GST activities and GSH content were decreased. Furthermore, silent information regulator protein 1 (SIRT1) gene expression was markedly down-regulated. Additionally, alterations of the trace elements; copper, manganese, zinc and DNA fragmentation was observed in the hepatic tissues of the intoxicated group. These effects were augmented in CCl4-intoxicated-γ-irradiated rats. However, the administration of GSO ameliorated these parameters. GSO exhibit protective effects on CCl4 induced acute liver injury in γ-irradiated rats that could be attributed to its potent antioxidant, anti-inflammatory and anti-apoptotic activities. The induction of the antioxidant enzymes activities, down-regulation of the CYP2E1, iNOS, Caspase-3 and NF-κB expression, up-regulation of the trace elements concentration levels and activation of SIRT1 gene expression are responsible for the improvement of the antioxidant and anti-inflammatory status in the hepatic tissues and could be claimed to be the hepatoprotective mechanism of GSO.

Inhibition of cyclic AMP response element-directed transcription by decoy oligonucleotides enhances tumor-specific radiosensitivity

The radiation stress induces cytotoxic responses of cell death as well as cytoprotective responses of cell survival. Understanding exact cellular mechanism and signal transduction pathways is important in improving cancer radiotherapy. Increasing evidence suggests that cyclic AMP response element binding protein (CREB)/activating transcription factor (ATF) family proteins act as a survival factor and a signaling molecule in response to stress. We postulated that CREB inhibition via CRE decoy oligonucleotide increases tumor cell sensitization to γ-irradiation-induced cytotoxic stress. In the present study, we demonstrate that CREB phosphorylation and CREB DNA-protein complex formation increased in time- and radiation dose-dependent manners, while there was no significant change in total protein level of CREB. In addition, CREB was phosphorylated in response to γ-irradiation through p38 MAPK pathway. Further investigation revealed that CREB blockade by decoy oligonucleotides functionally inhibited transactivation of CREB, and significantly increased radiosensitivity of multiple human cancer cell lines including TP53- and/or RB-mutated cells with minimal effects on normal cells. We also demonstrate that tumor cells ectopically expressing dominant negative mutant CREB (KCREB) and the cells treated with p38 MAPK inhibitors were more sensitive to γ-irradiation than wild type parental cells or control-treated cells. Taken together, we conclude that CREB protects tumor cells from γ-irradiation, and combination of CREB inhibition plus ionizing radiation will be a promising radiotherapeutic approach.

Structural, optical and magnetic properties of γ-irradiated SiO2 xerogel doped Fe2O3

The paper deals with the structure, morphology and magnetic properties of two different iron concentrations (20 and 33 mol.%) of Fe2O3-SiO2 nanocomposites, prepared by sol-gel technique and exposed to different gamma-irradiation doses (0, 30 and 60 kGy). The nanocomposites were investigated through XRD, TEM, SEM, FTIR and EPR measurements. Superparamagnetic iron (III) oxide nanoparticles with a narrow size distribution, dispersed over the amorphous silica matrix, are assumed to be present in all the samples before and after irradiation. Before irradiation, a lot of γ-Fe2O3 crystalline ferromagnetic nanoparticles are assumed to be formed particularly for sample containing 33 mol.% Fe2O3, while exposing the samples to irradiation results in the transformation of γ- to α-Fe2O3. Iron concentrations and/or irradiation of the samples are assumed to cause changes in the bond angles and/or bond lengths of the structural silicate units within network, as well, the increase of more defect centers induced by irradiation as evident through the variations of the IR bands intensity. The EPR results show both intensity and line width increase with increasing Fe2O3 concentration. The EPR signals for the samples consist of a well defined symmetrical broad signal at g≈2.0 ascribed to antiferromagnetic interactions between the Fe(2+) and Fe(3+) clusters. Condensed clusters of Fe(3+) ions are observed to give rise to a resonance line at g∼2 whose position and width do not depend on the Fe2O3 concentrations. The EPR signal intensity is observed to be significantly decreased in the sample 33 mol.% or stabilized in the sample 20 mol.% by γ-irradiation. This reflects simultaneous spin transformation from the high-spin state of Fe III to the low-spin state of Fe II. As a final point, an effort has been given to found the possibility to use one of these studied nanocomposite materials as candidate for radiation shielding purposes.

Nano-silymarin provides protection against γ-radiation-induced oxidative stress in cultured human embryonic kidney cells

Radiation can produce biological damage, mainly oxidative stress, via production of free radicals, including reactive oxygen species (ROS). Nanoparticles are of interest as radioprotective agents, particularly due to their high solubility and bioavailability. Silymarin is a hepatoprotective agent but has poor oral bioavailability. Silymarin was formulated as a nanoemulsion with the aim of improving its bioavailability and therapeutic efficacy. In the present study, we evaluated self-nanoemulsifying drug delivery systems (SNEDDS) formulated with surfactants and co-surfactants. Nano-silymarin was characterized by estimating % transmittance, globule size, and polydispersity index, and by transmission electron microscopy (TEM). The nano-silymarin obtained was in the range of 3-8nm diameter. With regard to DNA damage, measured by a plasmid relaxation assay, maximum protection was obtained at 10μg/mL. Cytotoxicity of nano-silymarin to human embryonic kidney (HEK) cells was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Protective efficacy against γ-radiation was assessed by reduction in micronucleus frequency and ROS generation, using the 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay. Radiation-induced apoptosis was estimated by microscopic analysis and cell-cycle estimation. Nano-silymarin was radioprotective, supporting the possibility of developing new approaches to radiation protection via nanotechnology.

Role of eaq⁻, ·OH and H· in radiolytic degradation of atrazine: a kinetic and mechanistic approach

The degradation of atrazine was investigated in aqueous solution by gamma-ray irradiation. 8.11 μM initial atrazine concentration could be completely removed in N₂ saturated solution by applying 3500 Gy radiation dose at a dose rate of 296 Gy h(-1). Significant removal of atrazine (i.e., 39.4%) was observed at an absorbed dose of 1184 Gy in air saturated solution and the removal efficiency was promoted to 50.5 and 65.4% in the presence of N₂O and N₂ gases, respectively. The relative contributions of hydrated electron, hydroxyl radical and hydrogen radical toward atrazine degradation were determined as ratio of observed dose constant (kobs) and found to be 5: 3: 1 for keaq(-): k·OH: kH·, respectively. The degradation efficiency of atrazine was 69.5, 55.6 and 37.3% at pH 12.1, 1.7 and 5.7, respectively. A degradation mechanism was proposed based on the identified degradation by-products by gas chromatography-mass spectrometry. Taking the relative contributions of oxidative and reductive species to atrazine degradation into account, reductive pathway proved to be a better approach for the radiolytic treatment of atrazine contaminated water.

A segmental duplication encompassing S-haplotype triggers pollen-part self-compatibility in Japanese pear (Pyrus pyrifolia)

Self-compatible mutants of self-incompatible crops have been extensively studied for research and agricultural purposes. Until now, the only known pollen-part self-compatible mutants in Rosaceae subtribe Pyrinae, which contains many important fruit trees, were polyploid. This study revealed that the pollen-part self-compatibility of breeding selection 415-1, a recently discovered mutant of Japanese pear (Pyrus pyrifolia) derived from γ-irradiated pollen, is caused by a duplication of an S-haplotype. In the progeny of 415-1, some plants had three S-haplotypes, two of which were from the pollen parent. Thus, 415-1 was able to produce pollen with two S-haplotypes, even though it was found to be diploid: the relative nuclear DNA content measured by flow cytometry showed no significant difference from that of a diploid cultivar. Inheritance patterns of simple sequence repeat (SSR) alleles in the same linkage group as the S-locus (LG 17) showed that some SSRs closely linked to S-haplotypes were duplicated in progeny containing the duplicated S-haplotype. These results indicate that the pollen-part self-compatibility of 415-1 is not caused by a mutation of pollen S factors in either one of the S-haplotypes, but by a segmental duplication encompassing the S-haplotype. Consequently, 415-1 can produce S-heteroallelic pollen grains that are capable of breaking down self-incompatibility (SI) by competitive interaction between the two different S factors in the pollen grain. 415-1 is the first diploid pollen-part self-compatible mutant with a duplicated S-haplotype to be discovered in the Pyrinae. The fact that 415-1 is not polyploid makes it particularly valuable for further studies of SI mechanisms.

Does quercetin protect human red blood cell membranes against γ-irradiation?

OBJECTIVES

Radioprotective potential of quercetin, a powerful free radical scavenger, was investigated in human red blood cells (RBCs) and in isolated RBC membranes exposed to γ-irradiation-induced oxidative stress.

METHODS

RBCs and RBC membrane suspensions were irradiated (50 Gy) in the presence of quercetin (2-50 µM). Oxidative damage of the membranes was analysed by protein carbonyl measurement (enzyme-linked immunosorbent assay). In RBCs, the concentration of glutathione (GSH) was determined. Lipid peroxidation in RBCs, and for comparison in plasma and peripheral lymphocytes, was quantified by the amount of thiobarbituric acid-reactive substances (TBARS). Radiation-induced damage of the RBC membrane integrity was evaluated by the degree of haemolysis.

RESULTS

Quercetin (50 µM) brought back the level of carbonyls to normal in γ-irradiated RBC membrane proteins and inhibited radiation-induced lipid peroxidation in plasma and lymphocytes, by 75 and 96%, respectively. However, it moderately decreased reduced/oxidized glutathione (GSH/GSSG) ratio and significantly increased TBARS concentrations, by 60 and 28% in irradiated and non-irradiated RBCs, respectively. Haemolysis rate was much higher in RBCs irradiated in the presence of quercetin vs. non antioxidant.

DISCUSSION

In non-cellular systems (RBC membranes or plasma) and in lymphocytes, quercetin shows antioxidative/radioprotective activity but in whole RBCs it acts as a pro-oxidant and a cytotoxic substance. The possible mechanisms of such action are discussed.

Novel functionalized mesopore of SBA-15 as prospective sorbent for praseodymium and lutetium

In the present work, results of γ-irradiation on normal and functionalized SBA-15 by aurintricarboxylic acid have been reported. Characterization of normal and functionalized SBA-15 particles before and after γ-irradiation was carried out using Fourier-transform infrared technique. Aurintricarboxylic acid ligand connected to SBA-15 was also analyzed using UV/Vis spectrophotometer. The modified sorbent was then used as a new sorbent for separation of trace amounts of praseodymium and lutetium ions from nuclear waste waters in batch techniques. Based on the results of distribution coefficients determination, and investigation of sorption process in various conditions, the parameters were optimized for separation lanthanides. It can be concluded that the functionalized SBA-15 is a promising sorbent for praseodymium and lutetium cations.