Different Doses Of Gamma Radiation Research Articles

Stability and quality improvement of shrimp patties by Asparagus racemosus and gamma irradiation

ABSTRACT The present study was conducted to determine the effect of gamma irradiation and Asparagus racemosus on the storage stability and shelf life of shrimp patties. Gamma irradiation (3 kGy and 5 kGy) and Asparagus racemosus powder (3%) were applied to measure microbial activity, physiochemical chemical analysis, antioxidant potential, TVBN value, TBARS value, and POV of shrimp patties. The total aerobic bacteria and coliform count were reduced with the increase in irradiation dose. The DPPH and TPC were decreased with irradiation dose but addition of 3% ARP increased the values. TVBN values significantly decreased at 0 day of storage and increased with storage time. The TBARS and peroxide values (POV) howed significant increase with the increase in irradiation dose at different storage (0, 7, 14, and 21 day). The minimum changes were observed in sensory attributes (i.e. appearance, taste, odor, texture, and overall acceptability) on different treatments at storage intervals. The aim of this study showed that different doses of gamma irradiation and Asparagus Racemosus are valuable to improve the shelf stability and quality of shrimp patties.

Optimization of Alpha-Amylase Production by a Local Bacillus paramycoides Isolate and Immobilization on Chitosan-Loaded Barium Ferrite Nanoparticles

We set out to isolate alpha-amylase producers from soil samples, optimize the production, and immobilize the enzyme on chitosan-loaded barium ferrite nanoparticles (CLBFNPs). Alpha-amylase producers were isolated on starch agar plates and confirmed by dinitrosalicylic acid assay. The potent isolate was identified by phenotypic methods, 16S-rRNA sequencing, and phylogenetic mapping. Sequential optimization of α-amylase production involved the use of Plackett–Burman (P–BD) and central composite designs (CCD), in addition to exposing the culture to different doses of gamma irradiation. Alpha-amylase was immobilized on CLBFNPs, and the nanocomposite was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy, with energy-dispersive analysis of X-ray analysis. Forty-five α-amylase producers were isolated from 100 soil samples. The highest activity (177.12 ± 6.12 U/mg) was detected in the MS009 isolate, which was identified as Bacillus paramycoides. The activity increased to 222.3 ± 5.07 U/mg when using the optimal culture conditions identified by P–BD and CCD, and to 319.45 ± 4.91 U/mg after exposing the culture to 6 kGy. Immobilization of α-amylase on CLBFNPs resulted in higher activity (246.85 ± 6.76 U/mg) compared to free α-amylase (222.254 ± 4.89 U/mg), in addition to retaining activity for up to five cycles of usage. Gamma irradiation improved α-amylase production, while immobilization on CLBFNPs enhanced activity, facilitated enzyme recovery, and enabled its repetitive use.

Radiation and lead nanoparticles effects on the mechanical properties of unidirectional carbon fiber/epoxy composites

This study investigates the effects of two different parameters on the mechanical properties of carbon fiber-epoxy composites. The two addressed parameters are the composite’s exposure to gamma radiation with different doses, and the incorporation of lead nanoparticles with different weight percentages in the epoxy matrix. Unidirectional carbon fiber-epoxy composites are manufactured using the hand layup vacuum bagging process, and they are characterized by tensile tests and scanning electron microscope. The first part of the study entails fabricating composite laminates with different weight percentages of lead nanoparticles, namely, 0wt%, 1wt%, 2wt%, 3wt%, 4wt% and 5wt%. The results show that composites incorporating lead nanoparticles up to 3wt% exhibit monotonically improved tensile strength and Young’s modulus without compromising their ductility. Whereas, degradation of these mechanical properties is observed with increasing lead content beyond 3wt%. For the second part of the study, composite specimens are exposed to different doses of gamma radiation, namely, 0, 25, 50, 75 and 100 kGy. It is observed that the tensile strength, the modulus of toughness and the ductility of the composites improve for radiation exposures up to 25 kGy. However, radiation exposures higher than 25 kGy lead to deterioration in the tensile strength, modulus of toughness and Young’s modulus with negligible effect on the ductility.

High luminescence of CdTe/CdSe/CdS core/shell/shell QDs: synthesis via a simple photochemical approach and gamma dosimetry application

In this research CdTe/CdSe/CdS core/shell/shell quantum dots (QDs) were synthesized by a photochemical approach using thioglycolic acid as capping agent and S2- source for CdS shell growth. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FT-IR), and Raman results confirmed formation of CdTe/CdSe/CdS core/shell/shell structure. Photoluminescence (PL) quantum yield (QY) of the CdTe QDs was 23% and 50 and 70% for CdTe/CdSe and CdTe/CdSe/CdS QDs, respectively. Effect of 60Co gamma irradiation on optical and structural properties of CdTe and CdTe/CdSe/CdS core/shell/shell QDs was investigated. The obtained results indicated stability of crystalline structure of QDs after gamma irradiation but PL intensity of the CdTe/CdSe/CdS QDs decreased gradually after receiving different doses of gamma irradiation with a red shift in PL peak position. The obtained results suggested these luminescence QDs as potential materials for gamma dosimetry.

Development of the Sterile Insect Technique to control the dengue vector Aedes aegypti (Linnaeus) in Sri Lanka.

The Sterile Insect Technique (SIT) is presently being tested to control dengue in several countries. SIT aims to cause the decline of the target insect population through the release of a sufficient number of sterilized male insects. This induces sterility in the female population, as females that mate with sterilized males produce no offspring. Male insects are sterilized through the use of ionizing irradiation. This study aimed to evaluate variable parameters that may affect irradiation in mosquito pupae. An Ae. aegypti colony was maintained under standard laboratory conditions. Male and female Ae. aegypti pupae were separated using a Fay and Morlan glass sorter and exposed to different doses of gamma radiation (40, 50, 60, 70 and 80 Gy) using a Co60 source. The effects of radiation on survival, flight ability and the reproductive capacity of Ae. aegypti were evaluated under laboratory conditions. In addition, mating competitiveness was evaluated for irradiated male Ae. aegypti mosquitoes to be used for future SIT programmes in Sri Lanka. Survival of irradiated pupae was reduced by irradiation in a dose-dependent manner but it was invariably greater than 90% in control, 40, 50, 60, 70 Gy in both male and female Ae. aegypti. Irradiation didn't show any significant adverse effects on flight ability of male and female mosquitoes, which consistently exceeded 90%. A similar number of eggs per female was observed between the non-irradiated groups and the irradiated groups for both irradiated males and females. Egg hatch rates were significantly lower when an irradiation dose above 50 Gy was used as compared to 40 Gy in both males and females. Irradiation at higher doses significantly reduced male and female survival when compared to the non-irradiated Ae. aegypti mosquitoes. Competitiveness index (C) scores of sterile and non-sterile males compared with non-irradiated male mosquitoes under laboratory and semi-field conditions were 0.56 and 0.51 respectively at 50 Gy. Based on the results obtained from the current study, a 50 Gy dose was selected as the optimal radiation dose for the production of sterile Ae. aegypti males for future SIT-based dengue control programmes aiming at the suppression of Ae. aegypti populations in Sri Lanka.

Effect of gamma radiation processing on the quality characteristics of anthocyanin rich ethnic rice cultivars

Rice (Oryza sativa L.) is one of the most important cereal crops that serve as staple food of more than 50% of the world population. In recent years great interest has been shown in pigmented & colored rice due to its culinary interest as well as associated health benefits. However, post harvest qualitative and quantitative losses in rice during storage through pests are significant; therefore strategies that are aimed at minimizing losses in the supply chain can have significant socio-economic impact as it may strengthen ‘Food Security’. Fumigation is quite often employed but it is being gradually phased out owing to health and environmental concerns. In the current investigation, effect of different doses of gamma radiation (0.25-1.0 kGy) on the quality attributes (gel consistency, water uptake, total anthocyanin content, phenolics, protein and antioxidant activity) of different prominent ethnic pigmented rice cultivars (5 types) from the state of Manipur, India was evaluated. The cultivars displayed significant variation in their physical quality attributes including dehusked grain color, grain weight and length/breadth ratio. No significant difference was observed in the gel consistency profile of these rice cultivars upon gamma radiation processing (0.25-1.0 kGy). A wide variation was observed in the total anthocyanin content (0.17-4.90 mgCy-3-glu/g in non-irradiated samples) for these pigmented rice cultivars and radiation processing was also observed to exert differential impact on the anthocyanin content (0.24-3.96 mgCy-3-glu/g in irradiated samples) in different cultivars. Total phenolics content (0.22-2.46 mgGAE/g in non-irradiated samples) marginally increased (0.32-2.47 mgGAE/g in irradiated samples) in all the rice cultivars upon radiation processing. Rice cultivars also displayed prominent antioxidant capacity (DPPH scavenging: 20.5-80.5% in non-irradiated samples) and this functional health protective property was found to be retained (DPPH scavenging: 20.8-80.7% in non-irradiated samples) upon gamma irradiation.

Adipose-Derived Mesenchymal Stem Cells Responses to Different Doses of Gamma Radiation.

Background: The effects of radiation on the cellular compartments of the tumor microenvironment (TME) might be essential in radiotherapy outcomes.Objective: We aimed to assess the effects of the different doses of gamma irradiation on viability, ABCA1 and MMP-9 expression in adipose-derived mesenchymal stem cells (ASCs) as a critical part of TME.Material and Methods: In this experimental study, ASCs were extracted from five healthy donors and irradiated with different doses of 5, 10 and 30 Gy of gamma. Then, RNA was extracted from irradiated ASCs and cDNA was synthesized. The viability of ASCs was determined at 24, 48, 72 and 168 h after irradiation using trypan blue staining. The expression of ABCA1 was checked by quantitative real-time (qRT)-PCR technique and the expression of MMP-9 protein was evaluated by western-blot. Results: Based on our findings, 10 Gy and 30 Gy but not 5 Gy of gamma irradiation significantly decreased the viability of ASCs after 24, 48, 72 and 168 h compared to the non-irradiated cells (P< 0.05). However, a dose of 5 Gy increased ABCA1 in ASCs significantly compared to 10 Gy and 30 Gy (P=0.01 and P=0.02, respectively). In addition, the analysis of western blot data showed that 5 Gy of gamma irradiation significantly increased the expression of MMP-9 in ASCs (P=0.019).Conclusion: It is concluded that various doses of gamma radiation elicit differential ASCs responses that may lead to different tumor cell reactions to the radiotherapy through bystander effects.

Radiation induced mutagenesis, physio-biochemical profiling and field evaluation of mutants in sugarcane cv. CoM 0265

Purpose Sugarcane is an important cash crop and is affected by soil salinity. CoM 0265, a moderately salt-tolerant variety grown in the Maharashtra region (India), has low sugar content. The present study was aimed to employ gamma ray induced in vitro mutagenesis with repeated and step-wise selection in sugarcane for the isolation and physio-biochemical profiling of the selected salt-tolerant mutants for improved agronomic performance and sugar content. Materials and methods Embryogenic callus culture of CoM 0265 variety was subjected to different doses of gamma radiation (10, 20, 30, 40, 50, and 60 Gy) followed by selection on NaCl containing media (50, 100, 150, 200, and 250 mM NaCl). The regenerated plantlets were hardened and selected based on ground nursery field trial on normal soil and saline field trial, in augmented block design for the selected mutant clones. Different physio-biochemical changes and activity of antioxidant enzymes were analyzed in the salt selected in vitro cultures and field-grown mutant clones. Results Dose optimization showed 40 Gy as the LD50 for gamma radiation and 150 mM NaCl as the dose for in vitro selection experiments. The selected mutant clones showed higher tissue water content (TWC), chlorophyll, and lower sodium content indicative of tolerance to salt stress. Catalase and peroxidase enzyme activities in the top visible dewlap (TVD) of the putative mutant clones were significantly higher than the control. The average yield and sucrose percent of the selected mutant clones were significantly higher than control checks in the saline field trial. Mutant clones M8457 and M8721 exhibited improved yield and commercial cane sugar over the parent control check varieties under saline field conditions. Catalase activity was strongly associated with TWC (r = 0.34) and chlorophyll content (r = 0.41) while it was negatively correlated with sodium ion content (r = –0.38). Peroxidase activity in TVD also showed a significant positive correlation with chlorophyll content (r = 0.42) and a negative correlation with sodium ion content (r=–0.39). The improvement in yield and CCS (t/ha) was strongly associated with the lower sodium ion content of the mutant clones (r=–0.54 and −0.53, respectively). Conclusions Gamma ray induced mutants were isolated for improved sucrose and high yield in sugarcane var. CoM 0265. The results suggest that gamma radiation induced mutations result in physiological and metabolomic alterations for better growth and adaptation under in vitro and field stress conditions in sugarcane. The improved mutants can be further useful for commercial cultivation in saline areas.

The Effect of Gamma Radiation on the Manufactured HgBa&lt;sub&gt;2&lt;/sub&gt;Ca&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;2.4&lt;/sub&gt;Ag&lt;sub&gt;0.6&lt;/sub&gt;O&lt;sub&gt;8+δ&lt;/sub&gt; Compound

In this article four samples of HgBa2Ca2Cu2.4Ag0.6O8+δ were prepared and irradiated with different doses of gamma radiation 6, 8 and 10 Mrad. The effects of gamma irradiation on structure of HgBa2Ca2Cu2.4Ag0.6O8+δ samples were characterized using X-ray diffraction. It was concluded that there effect on structure by gamma irradiation. Scherrer, crystallization, and Williamson equations were applied based on the X-ray diffraction diagram and for all gamma doses, to calculate crystal size, strain, and degree of crystallinity. It is observed through the results that gamma irradiation causes a change in the atomic density, crystal size, strain, degree of crystallinity and thus a change in the diffraction angle and intensity peaks. It was found that the highest crystal size was 69.3269 nm at 4MRad dose, crystallization is 69.3269 at 4MRad and the strain is 0.0068 when sample without radiation.

Effect of ionizing radiation on morphological characters and leaf nutrient content of sweet orange cv. Mosambi

In the present study, sweet orange cv. Mosambi mutants were developed through treating bud stick with different doses of gamma irradiation (10, 15, 20, 25, 30 and 35 Gray) and budded in situ on Jatti Khatti rootstock. Two years after the establishment of plants, the impact of ionizing radiations on the mutated population was studied for the alterations in growth and plant nutrient status, showing differential stimulatory and inhibitory dose dependent responses. Mutants developed with lower doses of gamma irradiation stimulated plant height in the mutants GS-3 (39.30 per cent) and GS-8 (40.80 per cent) developed from 15 and 20 Gy, respectively. Contrary to the stimulatory effects, higher irradiation doses inhibited plant height and other growth parameters in the mutants GS-16, GS-30, GS-32 and GS-34 developed from 35 Gy. The macro-nutrient concentrations were higher at lower doses of 10 and 15 Gy in the mutants GS-2, GS-3 and GS-8, while the micro-nutrient contents in the leaf tissue were higher in the mutants GS-21 and GS 14 developed from intermediate doses of 20 and 25 Gy. Although lower accumulation of macro-nutrients was observed at higher dosimetery, however, reverse trend was noticed with respect to the micro-nutrients, being minimum at the lowest dosimetery i.e., 10 Gy.

Improvement of Grain Quality Traits in Bread Wheat Genotypes Through Mutation Breeding Using Gamma Irradiation

This study was conducted to determine changes for some quality characters in M2, M3 and M4 mutated populations of three bread wheat genotypes irradiated by different gamma rays. The results showed that the genotypes significantly and variably differed in their response for various traits at different gamma rays doses in M2, M3, and M4 populations. The shifts per see from the controls for examined quality characters such as thousand-grain weight (TGW), test weight (TW), wet gluten content (GC), gluten index (GI), Zeleny sedimentation value (ZSV), and protein content (PC) in mutant populations were significant according to t-test analysis. The results showed that desired variations could be obtained for quality traits in M2, M3, and M4 generations with different doses of gamma irradiation depending on bread wheat genotypes. Although the shifts per see from the controls for ZSV, GC, and PC were significant, TGW, GI, and TW showed an unchanged or slightly negative response in the M2, M3, and M4 generations. It can be generally said that it may be more appropriate to perform selection after M4 generation for seed quality traits in mutant populations. Although the effect of mutagen doses varies depending on the character, genotype, and mutagenesis generation examined, it can be said that the most appropriategamma-rayy doses are 300 and 200 Gy doses because of causing significant shifts per see from the controls.

Effect of gamma radiation on gentiopicroside production in Gentiana kurroo Royle in vitro cultures

Gentiopicroside (GPD) is one of the vital bioactive molecules present in the rhizomes, roots and aerial parts of Gentiana kurroo Royle. In this study, callus and in vitro shoots cultures of G. kurroo were treated with different doses of gamma radiation to assess its effect on the concentration of GPD. The callus was established on MS media fortified with Indole-3-butyric acid (IBA) and Indole-3-acetic acid (IAA) and exposed to variable radiation doses (0, 10, 20, 30, 40, 50, or 60 Gy 60Co gamma rays). Similarly, in vitro shoots raised in MS media supplemented with 6-Benzylaminopurine (BAP) and IAA were irradiated at (0, 10, 20, 30, 40, 50, 60, or 70 Gy 60Co gamma rays). In vitro cell growth and GPD content were assessed during M1V1, M1V2, M1V3, and M1V4 (Mutation and Vegetative) generations. The lethal dose (LD50) for both callus and shoots were observed at 35 Gy. The results revealed that low radiation doses favored growth and showed increased GPD content in the callus cultures during M1V1 generation, but both parameters were reduced in the M1V2, M1V3 and M1V4 generations. However, shoots irradiated at low doses boosted the growth and GPD level during M1V2, M1V3 and M1V4 generations. This is the first report that used gamma radiation to show the effect of GPD elicitation in the genus Gentiana.

Germination and development of M1 seedlings of two Selliera radicans Cav. accessions subjected to gamma radiation

Selliera radicans is a creeping plant native to Chile, New Zealand and Australia. It is increasingly used in the ornamental industry, and there is interest in breeding it to create commercial varieties. The aim of this study was to determine the effects of different doses of gamma radiation applied to the seeds on the germination and development of seedlings (M1) and the LD50 of two accessions of Selliera radicans for use in the induction of mutations. Seeds of the Vichuquén and La Serena accessions were exposed to 0, 100, 200, 300, 400, 500, 600 and 700 Gy from a 60Co source. Weekly germination percentages along with seedling numbers and lengths were recorded. Vichuquén seeds were more sensitive to this physical agent. The LD50 was 243.9 Gy for Vichuquén and 445.6 Gy for La Serena. Seedling lengths reached almost 4 mm for Vichuquén and 11.3 mm for La Serena at 12 weeks after sowing. Doses lower than 200 Gy are recommended since higher doses do not allow the development of seedlings to the extended cotyledon stage. Highlights: This is the first radiosensitivity study for the Goodeniaceae family and therefore for the Selliera genus. This study shows the specific effect of gamma radiation at the level of germination and seedling formation according to accession of origin. This study could be used for the genetic improvement of Selliera radicans via the induction of mutations.

INVESTIGATION OF THE SHELF LIFE OF BANANA ‘MAS’ (Musa acuminata Colla) USING GAMMA IRRADIATION

To investigate the shelf life of banana ‘Mas’ (Musa acuminata Colla) using gamma rays in Malaysia. An experimental study to investigate the shelf life of banana Mas using different doses of gamma radiation. Different doses will be given to each group of banana Mas which are 0 (untreated control), 0.4, 0.8 and 1.2 kGy. The irradiated groups were being irradiated by gamma radiation at the National University of Malaysia (UKM) using Gamma Cell 220 Excel Cobalt-60 source. The observation was performed on the physical changes of the sample such as peel colour, decay rate, and physiological weight loss. Findings have shown that the high dose of gamma radiation caused the darkening of the peel and accelerate the ripening process depend on the varieties of the bananas. Among all, group B (0.4 kGy) has the lowest PWL (Physiological Weight Loss) and decay rate when compared to the other groups. The result of the one-way ANOVA test on the weight loss was not statistically significant. The dose of 0.4 kGy was the most effective one in delaying the ripening process for banana Mas when compared to the other group samples.

Effect of gamma irradiation on microbiological and nutritional properties of the freeze-dried berries

Abstract Lyophilization or freeze-drying is the technique of removing ice or other frozen solvents from a material through sublimation and the removal of bound water molecules through the process of desorption. Drying occurs in an absolute vacuum at temperatures from −40°C to −50°C. This technique is often used for the conservation of fruits, especially berries. During this process, the water changes from frozen to gaseous, with no thawing. Due to low temperatures and the high vacuum, most microorganisms are rendered inactive during the lyophilization process. However, if there is a necessity to destroy all microorganisms from treated food, subsequent irradiation with gamma rays is an appropriate method. This paper investigated the influence of different doses of gamma radiation on lyophilized berries’ microbiological characteristics. It was shown that the radiation dose of 7 kGy is sufficient to eliminate the total number of microorganisms (excluding molds) to the extent that the number falls below the permitted limit according t o the law on the microbiological safety of foodstuffs of the Republic of Serbia, and 5 kGy is enough for molds to be rendered inactive. It was also concluded that gamma irradiation does not affect the nutritional value of lyophilized berries.

NanoUPLC-QTOF-MS/MS Determination of Major Rosuvastatin Degradation Products Generated by Gamma Radiation in Aqueous Solution.

Rosuvastatin, a member of the statin family of drugs, is used to regulate high cholesterol levels in the human body. Moreover, rosuvastatin and other statins demonstrate a protective role against free radical-induced oxidative stress. Our research aimed to investigate the end-products of free radical-induced degradation of rosuvastatin. To induce the radical degradation, an aqueous solution of rosuvastatin was irradiated using different doses of gamma radiation (50–1000 Gy) under oxidative conditions. Rosuvastatin and related degradation products were separated on nanoC18 column under gradient elution, and identification was carried out on hyphenated nanoUPLC and nanoESI-QTOF mass spectrometer system. Elemental composition analysis using highly accurate mass measurements together with isotope fitting algorithm identified nine major degradation products. This is the first study of gamma radiation-induced degradation of rosuvastatin, where chemical structures, MS/MS fragmentation pathways and formation mechanisms of the resulting degradation products are detailly described. The presented results contribute to the understanding of the degradation pathway of rosuvastatin and possibly other statins under gamma radiation conditions.

Radio-protective efficacy of Gymnema sylvestre on Pangasius sutchi against gamma (60Co) irradiation

ABSTRACT Purpose Freshwater fish Pangasius sutchi was used in this study as a vertebrate model. We evaluated the induction of certain antioxidant enzymes in various vital organs. The radioprotective efficacy of Gymnema sylvestre leaves extract (GS) [25mg/kg Body Weight (B.W)] and its bioactive compound Gymnemagenin (GG) [0.3mg/kg B.W] was compared with Amifostine (Ami), the only radioprotector clinically approved by the US-FDA [Ami- 83.3mg/kg B.W] against different doses of gamma radiation – 60Co (Lethal Dose: LD30-9.2Gy, LD50-10.2Gy and LD70-11.4Gy). Materials and Methods This study was done via stress marker enzymes, cell cycle analysis (CCA) and DNA damage assay prediction with molecular docking, which are reported here for the first time. The results indicate an elevated LPO level and decreased level of CAT, SOD and GSH due to oxidative stress initiation by 60Co Ionizing Radiation (IR) on 4th day and slightly reduced on 32nd day while the reverse observed when the fishes were pre-treated with Ami, GS and GG. Similarly, CCA and dead/live cells counts were conducted with pre-treatment of Ami, GS and GG against 60Co IR dose (LD50-10.2Gy). Results In CCA, G0/G1 phase was observed to be the highest in Ami and lowest in GG, against 60Co IR doses 10.2Gy which was 51.76 ± 7.55. The dead cells range observed in pre-treated group of Ami, GS and GG was lowest in Ami and highest in GG and live cells (highest in Ami and lowest in GG) as compared to 60Co IR group (86.43 ± 3.42 and 8.77 ± 5.95). Thus, antioxidant profile improvement by oxidative stress reduction and gradual progression of different phases of cell cycle except the apoptotic phase along with the live cells counts indicates that the radio-protective efficacy of GS is similar to Ami. Conclusion Predictive assessment was carried out by docking of Ami, various components of GS with p53, NF-κβ cells and Rad51 proteins structures responsible for CCA, apoptosis and repair mechanism. These structural proteins were docked with other structural proteins like USP7, TNF-α and partner and localizer of BRCA2 associated (PALB2/BRCA2) complex which made us perform these systemic efforts to find the functional activity of these known radio-protectants.

Enhancement the Mycosynthesis of Selenium Nanoparticles by Using Gamma Radiation.

Selenium is a fundamental trace element of the living system. Microorganisms play a crucial role in the selenium cycle, both in the environment and in life. Biogenic selenium nanoparticles have shown promising prospects for use in medicine as an antioxidant and anticancer agent. In this study, SeNPs were biosynthesized by Penicillium citrinum. The spore suspension which was previously prepared was exposed to different doses of gamma radiation (10, 20, 30, 50, and 60 Gy). SeNPs were then produced by an irradiated P citrinum. UV spectroscopy, transmission electron microscopy, X-ray diffraction, and GSH content were assayed to evaluate the probability of P citrinum synthesizing SeNPs. In conclusion, irradiation of P citrinum by gamma ray enhances the mycosynthesis of SeNPs.

English

Maize (Zea mays), is a plant of economic and nutritional interest, which is often confronted with unfavorable environmental conditions, including water stress. This phenomenon forces the plants to considerably reduce their production by disturbing their metabolism. Seeds of maize of the variety EV8728 were subjected to different doses of gamma radiation (100, 200 and 300 grays) in order to induce mutations in plants that could lead to resistance to water stress. Thus, plants from gamma irradiated seeds were used to evaluate the impact of water stress on leaf physiological parameters (leaf area, density and pore area of stomata and assimilatory pigments). Water stress had a depressive effect on all leaf parameters in maize plants. The degree of sensitivity or tolerance of the plants depends on the dose of irradiation and the intensity of stress applied. The increase in the level of water stress reduces the leaf surface and that of the stomata pores. This in turn increases the density of stomata. In addition, chlorophyll a &nbsp;was more sensitive to the effect of water stress than chlorophyll b. Key words: Maize mutants, water stress, gamma irradiation, leaves, stomata ostioles.

Investigating the rus and petI operon expression patterns in exposed Acidithiobacillus ferrooxidans sp. FJ2 to different doses of gamma irradiation

The bioleaching process is developing as an economic and successful biotechnology method in the metallurgy industry. Acidithiobacillus ferrooxidans is one of the most important bacteria involved in uranium bioleaching which converts insoluble U4+ to soluble U6+ by oxidation of Fe2+ to Fe3+ using several periplasmic proteins encoded by the genes in rus and petI operons in its electron transport pathway. Accordingly, the purpose of this study was to consider the expression of these genes through exposed A. ferrooxidans sp. FJ2 to γ-ray in 17 different doses targeting uranium extraction yield.Acidithiobacillus ferrooxidans sp. FJ2 was irradiated by gamma rays at 25, 50, 75, 100, 150, 300, 450, 600, 750 Gy and 1, 2, 5, 10, 15, 20, 25 and 30 kGy doses. Moreover, the Eh value of 9k culture media was measured as special screening criteria to select the four treatments. The selected bacteria were cultured in 9k media, containing 50% uranium ore powder in the bioleaching process. Then, the value of pH & Eh of culture media, Fe2+ and uranium concentrations in 4, 8 and 13 day's period of incubation were measured. In followings, the expression levels of cyc1, cyc2, rus, coxB, petA, petB, petC and cycA genes at the end of each period were investigated by real-time PCR.Overall, all samples demonstrated a decrease in pH value and Fe2+ concentration and an increase in Eh value and U concentration in time intervals. The gamma irradiation in given doses raised the expression levels of all genes encoded in rus and petI operons, except petB gene during the bioleaching process, although, it had no effect either on the pH, Eh values or on Fe2+ and uranium concentrations.This result implies that during the oxidation of ferrous iron and formation of Jarosite sediment, the decreasing trend of pH and the increasing trend of Eh occurred in all samples. However, the differences in expression of the genes of rus and petI operons in the samples did not have an effect on uranium extraction.