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In this study, a hidden pitfall in the production of commercial tryptose soya agar (TSA) media sterilized with cobalt 60 irradiation was identified, and the applicability of TSA media was also determined. In addition, a strain of Bacillus firmus ( B. firmus ) with a high catalase activity, named GL3, was screened, and the conditions affecting the activity of its catalase were optimized. The 5 kinds of irradiated TSA media, named A, B, C, D, and E, were stored for 0 days, 15 days, 30 days, and 45 days, and their growth promoting ability, inhibitory properties, and sterility were analyzed to guarantee their suitability. The irradiated TSA media C had abnormal colony counts when Staphylococcus aureus ( S. aureus ) ATCC 6538 and Bacillus ginsengihumi ( B. ginsengihumi ) were used as the inocula, and both bacteria resumed normal growth when the media were stored for 15 days or the catalase was added. Screening of the significant variables and optimization of the catalase activity was performed using a Plackett–Burman design (PBD) and response surface methodology (RSM). The GL3 exhibited high catalase activity and stable catalase properties at 20–60° and pH 7.0–10.0. Under optimal conditions, the activity of catalase reached 20,668 U/mL. The abnormal counts of plates can be eliminated by increasing the storage days of the irradiated media during the effective period or by adding optimal fermentation liquid from B. firmus GL3. The high catalase activity and stable enzymatic properties of B. firmus GL3 have potential uses in industrial food applications.

In vivo dosimetry is a quality assurance tool that provides post-treatment measurement of the absorbed dose as delivered to the patient. This dosimetry compares the prescribed and measured dose delivered to the target volume. In this study, a tissue-equivalent water phantom provided the simulation of the human environment. The skin and entrance doses were measured using GafChromic EBT2 film for a Theratron® Equinox Cobalt-60 teletherapy machine. We examined the behaviors of unencapsulated films and custom-made film encapsulation. Films were cut to 1 cm × 1 cm, calibrated, and used to assess skin dose depositions and entrance dose. We examined the response of the film for variations in field size, source to skin distance (SSD), gantry angle and wedge angle. The estimated uncertainty in EBT2 film for absorbed dose measurement in phantom was ±1.72%. Comparison of the measurements of the two film configurations for the various irradiation parameters were field size (p = 0.0193, α = 0.05, n = 11), gantry angle (p = 0.0018, α = 0.05, n = 24), SSD (p = 0.1802, α = 0.05, n = 11) and wedge angle (p = 0.6834, α = 0.05, n = 4). For a prescribed dose of 200 cGy and at reference conditions (open field 10 cm x 10 cm, SSD = 100 cm, and gantry angle = 0º), the measured skin dose using the encapsulation material was 70% while that measured with the unencapsulated film was 24%. At reference irradiation conditions, the measured skin dose using the unencapsulated film was higher for open field configurations (24%) than wedged field configurations (19%). Estimation of the entrance dose using the unencapsulated film was within 3% of the prescribed dose. GafChromic EBT2 film measurements were significantly affected at larger field sizes and gantry angles. Furthermore, we determined a high accuracy in entrance dose estimations using the film.

Native to Iran, seedless barberry ( Berberis vulgaris L.) is a nutritionally and economically important crop prized for its therapeutic uses and food industry applications. Nevertheless, the vegetative propagation of the plant and lack of seeds limit conventional breeding techniques, therefore reducing genetic variation and impeding cultivars improvement. This work sought to maximize gamma radiation dosages to cause mutations in seedless barberry hence increasing genetic variability for breeding projects. Hardwood cuttings were subjected to gamma radiation dosages of 0 (control), 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 Gy using a Cobalt-60 source. Under both in vitro and in vivo settings, the impacts on survival rates, leaf and shoot development, and morphometric features were assessed. Results revealed that rising radiation doses significantly reduced survival rates and growth metrics. The LD 50 (Lethal dose) was determined to be roughly 19 Gy for the in vivo and 13.6 Gy for the in vitro. Gamma irradiation negatively influenced plant growth according to values for leaf length, leaf width, fresh weight, and dry weight growth reduction (GR 50 ). Optimal dosages for causing mutations, while preserving survival, were found to be 15 Gy for the in vivo and 10 Gy for the in vitro.

Butenyl-spinosyn, derived from Saccharopolyspora pogona , is a broad-spectrum and effective bioinsecticide. However, the regulatory mechanism affecting butenyl-spinosyn synthesis has not been fully elucidated, which hindered the improvement of production. Here, a high-production strain S. pogona H2 was generated by Cobalt-60 γ-ray mutagenesis, which showed a 2.7-fold increase in production compared to the wild-type strain S. pogona ASAGF58. A comparative transcriptomic analysis between S. pogona ASAGF58 and H2 was performed to elucidate the high-production mechanism that more precursors and energy were used to synthesize of butenyl-spinosyn. Fortunately, a PurR family transcriptional regulator TF00350 was discovered. TF00350 overexpression strain RS00350 induced morphological differentiation and butenyl-spinosyn production, ultimately leading to a 5.5-fold increase in butenyl-spinosyn production (141.5 ± 1.03 mg/L). Through transcriptomics analysis, most genes related to purine metabolism pathway were downregulated, and the butenyl-spinosyn biosynthesis gene was upregulated by increasing the concentration of c-di-GMP and decreasing the concentration of c-di-AMP. These results provide valuable insights for further mining key regulators and improving butenyl-spinosyn production. Key points • A high production strain of S. pogona H2 was obtained by 60 Co γ-ray mutagenesis. • Positive regulator TF00350 identified by transcriptomics, increasing butenyl-spinosyn production by 5.5-fold. • TF00350 regulated of butenyl-spinosyn production by second messengers.

Wheat ( Triticum aestivum L.) serves as a critically important staple crop worldwide, and mutation breeding through Cobalt-60 ( 60 Co-γ) radiation has been widely adopted as an effective strategy for genetic improvement. In this study, ten wheat cultivars from Shandong, Henan, and Hebei were subjected to 60 Co-γ irradiation to develop an M 2 mutant population comprising 10,350,000 lines. Systematic screening M 2 mutant population under natural conditions identified 158 freezing-tolerant mutants, 441 saline-alkali-tolerant mutants, and >5,000 mutants with changed yield or quality traits. This population represents a valuable genetic resource for collaborative research and provides a powerful platform for functional genomics studies and breeding applications.

Aim: To assess the cytological effects of Gamma rays on the pollen mother cells and post meiotic products of Lepidium sativum Linn, which resulted in isolation of translocation heterozygote and aneuploid gametes. Methodology: During the experiment, parameters such as Meiotic stages, chromosomal structure, and pollen fertility were studied. Fresh seeds of Garden cress were orderly arranged in plastic and divided into four groups. The fresh seeds of each group were individually irradiated with 60Gy, 150Gy, 300Gy, 450Gy and 600Gy @ 7.247KGyh\" in the Floriculture Laboratory of National Botanical Research Institute (NBRI), Lucknow (India). The source for gamma ray irradiation was Cobalt-60. The irradiated seeds were sown in triplicates along with their respective controls. Results: Meiotic analysis of pollen mother cells (PMCs) at 300Gy showed translocation heterozygotes, however, in the control sets, the rate was negligible and phenotypically the plants were weak and short heighted. The cytological illustration of chromosomal configuration at diakinesis and metaphase I exhibited the superiority of tetravalents, bivalent and other forms of chromosomal associations such as multivalents. The induced translocation heterozygotes resulted in stickiness at metaphase and anaphase states along with the formation of bridges at anaphase stage. Due to chromosomal anomalies, the pollen fertility was reduced to 37.54±0.25% in contrast to control plants (98.20±0.16%). Interpretation: The current research work would be of paramount interest as translocation heterozygote serves as a source for raising aneuploid offspring having novel genetic combinations.

Effects of gamma and X-ray treatments were studied on three varieties of Coffea arabica (Kent, Mundo Novo and Geisha) to determine their radiosensitivity and relative biological effects. The coffee varieties seeds were subjected to 0, 50, 100, 150, 200 and 400 Gy of gamma and X-rays from Cobalt 60 ( 60 Co) source irradiation. The irradiated seeds were pre-germinated in Petri dishes placed in a germination chamber, whilst some were sown in the greenhouse for germination studies. Data were collected on germination date and rate, root and hypocotyl length to determine the relative biological effectiveness of treatments and the optimum dose. The results showed varieties responding differently to the irradiations and doses. There was a decrease in germination with increasing doses of the irradiation. The X-ray-treated seeds had less germination percentage and seedling vigour measured at 28 days after treatment compared to the gamma-irradiated seeds. The irradiation effects on germination suggest that lower doses of X-rays give the same Relative Biological Effects as higher gamma doses for both growth chamber and greenhouse germination for Geisha at LD 50 , where the effects were similar for the two irradiations. Whereas 50–100 Gy stimulated germination and seedling vigour, 150 Gy adversely affected germination and no germination occurred at 200–400 Gy. The study concluded that all the coffee varieties evaluated are sensitive to gamma and X-ray irradiation in terms of germination, seedling vigour and biological effects with an optimum dose of 50–100 Gy. Therefore, both gamma and X-rays could be utilized in a future mutational breeding programme for coffee seedlings.

Objective: This work aims to set up the correlation between height and absorbed dose using commercial acrylic dosimeters, through a mapping of the absorbed dose distribution in a panoramic cobalt-60 gamma irradiator. This study is essential for defining a safe limit for stacking boxes having materials subject to gamma irradiation, aiming to maintain service quality and optimize space in the irradiation chamber.   Theoretical Framework: Dosimetry is an important function in radiation processing, where large, absorbed doses and dose rates from photon must be measured with reasonable accuracy. Proper calibration and traceability of routine dosimetry systems to standard are crucial to the success of large-volume radiation processes. It is essential that users perform their own separate calibration for their own instrumentation and conditions of use.   Method: The samples to be irradiated is placing in specific positions, the dose value to be received by each sample is known. Four absorbed dose locations were chosen (1, 2, 3, and 5 kGy). Sixty Amber Perspex 3042 dosimeters from the same batch were used to analyze the correlation between height and absorbed dose. The procedure adopted involved calculating an absorbed dose point in the irradiator that delivers a dose of 2.5 kGy and covers a 24-hour irradiation period. After irradiation, the dosimeters were analyzed with a spectrophotometer at 603 nm to obtain absorbance values.   Results and Discussion: The results showed that the radiation field remains homogeneous up to a height of 1.60 m, up to 2 m from the Co-60 source. It was concluded that the boxes can be safely positioned up to this height without significant variation in the absorbed dose. To achieve the target dose of 2.5 kGy, it is recommended to adjust the distance between the boxes and the radiation source, allowing the absorbed dose to be optimized without compromising the homogeneity of the radiation field. Research Implications: It was concluded that the boxes can be safely positioned up to heights up to 1.60 m at a distance 2 m from the source, without significant variation in the absorbed dose. To achieve the target dose of 2.5 kGy, it is recommended to adjust the distance between the boxes and the radiation source, allowing the absorbed dose to be optimized without compromising the homogeneity of the radiation field.   Originality/Value: This experimental work is important for the quality and reliability of the irradiations performed in this laboratory. Experimental work validates theoretical predictions.

This study aims to observe the accelerated aging effect of 60 Co gamma (γ) irradiation on poly (methyl methacrylate) (PMMA) under extreme conditions and determine the influence of different media states on aging. PMMA samples were prepared at room temperature under varying media conditions, including air and deionized water immersion. Then, the samples were irradiated with different doses (50, 250, 500, and 1000 KGy) of 60 Co γ-rays. The compositional changes of the PMMA samples exposed to the rays at different periods were determined via Fourier transform infrared spectroscopy. The light transmission of the samples was characterized through ultraviolet–visible spectrophotometry, and the surface wettability of the samples was assessed via water contact angle measurements. Surface and microscopic changes in material morphology were analyzed using optical microscopy, ImageJ software, and scanning electron microscopy. Relative molecular mass and glass transition temperature were analyzed via gel permeation chromatography and differential scanning calorimetry. Thus, a comprehensive analysis of the effect of 60 Co γ irradiation on the aging properties of PMMA was performed.