60Co Γ-radiation Research Articles

Tap Water Shorts the Lifespan of Mice with Prolonged Exposure to Fractionated γ-Radiation

Assessing the role of social factors in the formation of radioresistance in chronic exposure and finding ways to increase it are important for understanding the mechanisms of the damaging effects of radiation and developing practical methods for reducing radiation risk in professionals exposed to ionizing radiation and patients undergoing radiation therapy. In this work, we investigated the ability to influence the lifespan of animals exposed to γ-radiation fractionally for a long time by replacing drinking water from tap water to distilled water. Female ICR mice (CD-1) were exposed to total 60Co γ radiation weekly in fractions for 33 weeks starting at 9 weeks of age. The dose of a single irradiation was 50 mGy, the average dose rate was 2 mGy/sec. The total radiation dose was 1.65 Gy. Control non-irradiated mice and irradiated animals were divided into 2 groups. The first received tap water, and the second received distilled water throughout the experiment. Non-irradiated animals kept on tap water showed a statistically insignificant (log-rank test, p = 0.483) reduction in average life expectancy compared to mice kept on distilled water. In animals after exposure to 60Co γ-radiation, a statistically significant (p = 0.0013) decrease in life expectancy was noted when kept on tap water and statistically insignificant (p = 0.1511) when kept on distilled water. Tap water and irradiation showed a clear synergy with a combined effect on the body of mice, expressed in a more than threefold decrease in the period of post-radiation shortening of life expectancy. Distilled water reduced the rate of death of irradiated animals and modified the rate of death of non-irradiated animals. Our data demonstrate that the reduction in life expectancy of mice kept on tap water caused by long-term fractionated irradiation can be reduced when animals are kept on distilled water.

Study on the preservation effect of 60Co-γ ray irradiation on potatoes

To evaluate the effect of irradiation on the preservation of potatoes, fresh potatoes were selected as the irradiation objects, and irradiated with 60Co-γ radiation source for 0, 100, 200, 500 and 1000 Gy, respectively. During the irradiation, the well-packaged Y1.79Bi0.01Eu0.2MgTiO6 novel thermoluminescence dosimeter material was placed together with the potatoes at the same position. Then, the potatoes were stored in the same temperature and humidity environment, and the quality changes of the potatoes were observed. The Y1.79Bi0.01Eu0.2MgTiO6 material had good performance indicators, and was used to measure the irradiation dose of the potatoes. The experiment showed that irradiation could appropriately extend the storage time of potatoes, and gamma irradiation of about 1000 Gy could achieve the best preservation effect. The main pathogenic fungi that cause dry rot of potatoes were Fusarium solani and Fusarium oxysporum, and the appropriate dose of 60Co-γ irradiation could effectively inhibit the spread and growth of these fungi.

Synthesis, morphology and dosimetric properties of Cr3+ activated Ca2Al2SiO7 nanophosphor prepared via sol-gel route

In this study, the structural, morphological, photoluminescence (PL), and dosimetric properties of Ca2-xAl2SiO7: xCr3+, at various Cr3+ concentrations (0 ≤ x ≤ 1 mol%) have been studied. The phosphor material was synthesized via sol-gel route with an octadecylamine as a catalyst. The average crystallite sizes were estimated to be in the range 21–30 nm using the modified Scherrer method which are in good agreement with data yielded by TEM micrographs. The energy-dispersive X-ray (EDX) spectra with scanning electron microscope (SEM) data confirm the homogeneous existence, and distribution of constituent elements within the structure and approved the sol-gel preparation method. PL spectra shows that Cr3+ doped Ca2Al2SiO7 structure has shoulder broadening and maximum peaks maintained at 442 ± 3.0 and 491 ± 3.02 nm upon 337 nm excitation which caused by 4F (4A2→4T2), 4F (4A2→4T1), and 4P (4A2→4T1) electronic spin-allowed transitions. Thermoluminescenc (TL) sensitivity characteristics of the obtained samples were scrutinized using Co-60 γ-radiation source. Cr0.4 sample was found to be optimum and its TL intensity increases linearly with increasing γ-doses from 0.5 up to 10 Gy. An accuracy using relative standard deviation (RSD) calculations of the homogenous study for Cr0.4 was found to be 4.02% (<10%, accepted due to ISO rules). Threshold dose of Cr0.4 sample was computed to be about 258 μGy. Acquired results of photon attenuation parameters estimations of Ca2Al2SiO7 composition using Phy-X PSD online program show that this composition is a bone equivalent dosimeter. According to this article, Cr0.4 doped Ca2Al2SiO7 sample can be considered as useful TL-material in various dosimetric applications.

Screening 60Co-γ Irradiated Camellia oleifera Lines for Anthracnose-Resistant

Camellia oleifera C. Abel is a woody oil crop with multiple purposes. This study aims to investigate the mutagenic effects of 60Co-γ radiation on C. oleifera seedlings and to screen anthracnose-resistant mutants. Two C. oleifera varieties were investigated: ‘Xianglin 1’ (XL1) and ‘Xianglin 210’ (XL210). Seeds were irradiated with 0 Gy, 30 Gy, 50 Gy, and 80 Gy of 60Co-γ, and after one year of planting, the mutagenic lines were studied, and disease-resistant mutants were screened. Results showed that as the radiation intensity was increased, the emergence percentage of both C. oleifera XL210 and XL1 was significantly decreased. Radiation significantly changed the SOD and POD activities in both varieties. Furthermore, 80 Gy irradiated lines showed reduced anthracnose resistance in both varieties. However, 50 Gy irradiated lines showed enhanced disease resistance in XL210 while reducing it in XL1. The 30 Gy irradiated lines did not affect the disease resistance of either variety. Colletotrichum gloeosporioides infection tests were conducted on 94 mutant C. oleifera seedlings, resulting in 8 highly resistant mutants (A3, A8, A10, A19, A21, A32, A35, B17) and 3 susceptible mutants (A4, B15, B27) in XL210 and XL1. Differences in SOD and POD activities led to variations in disease resistance among different mutants. Additionally, the expression levels of CoSOD1, CoPOD, CoIDD4, and CoWKRY78 were varied among the different mutants. This study delivers the screening of disease-resistant mutants in C. oleifera through mutagenic breeding, providing material for the development of new C. oleifera varieties and serving as a resource for further research in mutagenic breeding.

Using Transcriptomics to Determine the Mechanism for the Resistance to Fusarium Head Blight of a Wheat-Th. elongatum Translocation Line.

Fusarium head blight (FHB), caused by the Fusarium graminearum species complex, is a destructive disease in wheat worldwide. The lack of FHB-resistant germplasm is a barrier in wheat breeding for resistance to FHB. Thinopyrum elongatum is an important relative that has been successfully used for the genetic improvement of wheat. In this study, a translocation line, YNM158, with the YM158 genetic background carrying a fragment of diploid Th. elongatum 7EL chromosome created using 60Co-γ radiation, showed high resistance to FHB under both field and greenhouse conditions. Transcriptome analysis confirmed that the horizontal transfer gene, encoding glutathione S-transferase (GST), is an important contributor to FHB resistance in the pathogen infection stage, whereas the 7EL chromosome fragment carries other genes regulated by F. graminearum during the colonization stage. Introgression of the 7EL fragment affected the expression of wheat genes that were enriched in resistance pathways, including the phosphatidylinositol signaling system, protein processing in the endoplasmic reticulum, plant-pathogen interaction, and the mitogen-activated protein kinase (MAPK) signaling pathway at different stages after F. graminearium infection. This study provides a novel germplasm for wheat resistance to FHB and new insights into the molecular mechanisms of wheat resistance to FHB.

Preliminary Promising Findings for Manganese Chloride as a Novel Radiation Countermeasure Against Acute Radiation Syndrome.

Military members and first responders may, at moment's notice, be asked to assist in incidents that may result in radiation exposure such as Operation Tomadachi in which the U.S. Navy provided significant relief for the Fukushima Daiichi Nuclear Reactor accident in Japan after an earthquake and tsunami in 2011. We are also currently facing potential threats from nuclear power plants in the Ukraine should a power disruption to a nuclear plant interfere with cooling or other safety measures. Exposure to high doses of radiation results in acute radiation syndrome (ARS) characterized by symptoms arising from hematopoietic, gastrointestinal, and neurovascular injuries. Although there are mitigators FDA approved to treat ARS, there are currently no FDA-approved prophylactic medical interventions to help protect persons who may need to respond to radiation emergencies. There is strong evidence that manganese (Mn) has radiation protective efficacy as a promising prophylactic countermeasure. All animal procedures were approved by the Institutional Animal Care and Use Committee. Male and female B6D2F1J mice, 10 to 11 weeks old, were used for neurotoxicity studies and temporal effects of Mn. Four groups were evaluated: (1) vehicle injection, (2) dose of 4.5 mg/kg for 3 days, (3) dose of 13.5 mg/kg, and (4) sham. Irradiated mice were exposed to 9.5 Gy whole body Co60 γ-radiation. MRI was performed with a high dose of manganese chloride (MnCl2) (150 mg/kg) to assess the distribution of the MnCl2. The mice have promising survival curves (highest survival-13.5 mg/kg dose over 3 days of MnCl2 at 80% [87% female, 73% male] P = 0.0004). The complete blood count (CBC) results demonstrated a typical hematopoietic response in all of the irradiated groups, followed by mildly accelerated recovery by day 28 in the treated groups. No difference between groups was measured by Rota Rod, DigiGait, and Y-maze. Histologic evaluation of the bone marrow sections in the group given 13.5 mg/kg dose over 3 days had the best return to cellularity at 80%. MRI showed a systemic distribution of MnCl2. The preliminary data suggest that a dose of 13.5 mg/kg of MnCl2 given over 3 days prior to exposure of radiation may have a protective benefit while not exhibiting the neurobehavioral problems. A countermeasure that can prophylactically protect emergency personnel entering an area contaminated with high levels of radiation is needed, especially in light that nuclear accidents are a continued global threat. There is a need for a protective agent with easy long-term storage, easy to transport, easy to administer, and low cost. Histologic evaluation supports the promising effect of MnCl2 in protecting tissue, especially the bone marrow using the dose given over 3 days (4.5 mg/kg per day) of MnCl2. Initial experiments show that MnCl2 is a promising safe and effective prophylactic countermeasure against ARS. MRI data support the systemic distribution of MnCl2 which is needed in order to protect multiple tissues in the body. The pathology data in bone marrow and the brain support faster recovery from radiation exposure in the treated animals and decreased organ damage.

The impact of post-radiation high-temperature shear grinding on the thermal and mechanical properties of polypropylene

The effect of input doses of 60Co γ-radiation from 80 to 12,000 kGy on the thermophysical properties and thermal stability of samples of polypropylene granules and powder obtained by high temperature shear grinding of irradiated granules, as well as on the tensile strength properties of a plate made from irradiated granules and their corresponding powders, was studied. The thermophysical properties of the powder are determined by the changes introduced by radiation into the initial polymer granules. The effects of radiation in air (environments with oxygen) were studied. Grinding redistributes oxygen-containing functional groups from the surface layer of irradiated granules throughout the entire volume of the obtained powder leading to the destruction of polymer chains as there is a component due to thermal destruction of radiolyzed polymer chains. High-temperature shear grinding of irradiated granules has a significant effect on the product powder, reducing its thermal stability but increasing the tensile strength of plates pressed from it at low absorbed doses. The current work shows that radiation treatment coupled with high temperature shear grinding could be a method for modifying the properties of polymers so that polypropylene waste can be processed for other applications.

Adaptive responses of erythritol-producing Yarrowia lipolytica to thermal stress after evolution

Elucidation of the thermotolerance mechanism of erythritol-producing Yarrowia lipolytica is of great significance to breed robust industrial strains and reduce cost. This study aimed to breed thermotolerant Y. lipolytica and investigate the mechanism underlying the thermotolerant phenotype. Yarrowia lipolytica HT34, Yarrowia lipolytica HT36, and Yarrowia lipolytica HT385 that were capable of growing at 34 °C, 36 °C, and 38.5 °C, respectively, were obtained within 150 days (352 generations) by adaptive laboratory evolution (ALE) integrated with 60Co-γ radiation and ultraviolet ray radiation. Comparative genomics analysis showed that genes involved in signal transduction, transcription, and translation regulation were mutated during adaptive evolution. Further, we demonstrated that thermal stress increased the expression of genes related to DNA replication and repair, ceramide and steroid synthesis, and the degradation of branched amino acid (BCAA) and free fatty acid (FFA), while inhibiting the expression of genes involved in glycolysis and the citrate cycle. Erythritol production in thermotolerant strains was remarkably inhibited, which might result from the differential expression of genes involved in erythritol metabolism. Exogenous addition of BCAA and soybean oil promoted the growth of HT385, highlighting the importance of BCAA and FFA in thermal stress response. Additionally, overexpression of 11 out of the 18 upregulated genes individually enabled Yarrowia lipolytica CA20 to grow at 34 °C, of which genes A000121, A003183, and A005690 had a better effect. Collectively, this study provides novel insights into the adaptation mechanism of Y. lipolytica to thermal stress, which will be conducive to the construction of thermotolerant erythritol-producing strains.Key points• ALE combined with mutagenesis is efficient for breeding thermotolerant Y. lipolytica• Genes encoding global regulators are mutated during thermal adaptive evolution• Ceramide and BCAA are critical molecules for cells to tolerate thermal stress

Gamma radiolytic degradation of catechin in aqueous solution

Catechin is a polyphenol belonging to flavan-3-ol class, most abundantly found in tea. Due to its remarkable metal chelation property, it can be used as a suitable radionuclide carrier in the field of radiopharmaceuticals. Therefore, aqueous radiation stability of catechin was studied under 60Co-γ radiation environment. The degradation efficiency was ∼20% for initial concentration of 50 mg L−1 and ∼50% for initial concentration of 25 mg L−1 with application of 1.2 kGy dose. The degradation kinetics followed the pseudo first order kinetic reaction model. The radiation chemical yield value implied that presence of reactive species from gamma-induced radiolysis of water has a profound impact on the degradation of catechin in aqueous solution. Degradation was more favoured in neutral medium compared to acidic medium. Addition of ethanol significantly decreased the degradation efficiency.

Screening of Selenium/Glutathione-Enriched Candida utilis and Its Anti-inflammatory and Antioxidant Activities in Mice.

This study aimed to screen a mutant of Candida utilis SE-172 with high selenite tolerance and glutathione (GSH) biosynthesis capability via 60Co γ-radiation mutagenesis to prepare selenium (Se)-enriched yeast. The maximal intracellular contents of GSH and organic Se of 22.94 mg/g and 1308.1 μg/g were obtained, respectively, under a batch culture of SE-172. The physiological mechanism underlying increased GSH and organic Se contents in Se/GSH-enriched C. utilis SE-172 was revealed based on assaying activities of γ-glutamylcysteine synthase (γ-GCS) involved in GSH biosynthesis and selenophosphate synthase (SPS) related to organic Se bioconversion, and by determining intracellular ATP and NADH contents and ATP/ADP and NADH/NAD+ ratios associated with energy supply and regeneration. Moreover, the effect of this selenized yeast on anti-inflammatory and antioxidant activities in mice with colitis was investigated. The supplementation of Se/GSH-enriched yeast decreased the dextran sodium sulfate-induced damage to colon tissues, reduced the expression of pro-inflammatory factors [interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α)] in serum, increased the antioxidant-related enzyme [superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px)] activities, and decreased the malondialdehyde content in colon. The Se/GSH-enriched C. utilis SE-172 showed potent anti-inflammatory and antioxidant activities in mice with colitis.

Targeted Pubic Neoantigen Immunotherapy Using Encapsulated Nanoparticles, Directed by Radiation

We tested a treatment combining radiotherapy with pubic neoantigen nanoparticles of CAND1 and ADGRF5-II (120 ± 56 nm) in nanocapsules detectable by computed tomography (CT) (545± 24 nm) with IFN γ or PD-L1 antibody (Ab), which released their contents upon radiation exposure. We performed two radiotherapy sessions: 1) induction of MHC-I and II in tumor cells and dendritic cells (DC) by the first round of radiation with concurrently released IFN γ from nanoparticles; 2) targeted neoantigen immunotherapy with PD-L1 blockade by the second round of radiation, elicited by CAND1-specific CD8+T-cell and ADGRF5-II-specific CD4+T-cell, related to induced MHC-I and MHC-II in session 1, respectively. For session one, nanocapsules were generated by mixing iopamiron and 15 mg IFN γ with a 1.0 mL solution containing 4.0% alginate, 3.0% hyaluronate, and 1 μg/mL P-selectin. This mixture was sprayed into 0.5 mmol/l FeCl2 supplemented with 1 µg/mL anti-VEGFR-1/2 Ab. For session two, Mixture of 110 fmol CAND1 and fmol ADGRF5-II, were encapsulated into poly lactic-co-Glycolic acid (PLGA) particle, using nanoprecitation method. Those particles were encapsulated by mixing into above alginate-hyaluronate cocktail with 400 mg PD-L1 antibody (Ab), then sprayed into 0.5 mmol/l FeCl2 supplemented with P-selectin Ab. In session one, 1 × 1010 nanocapsules were intravenously injected into BALB/c mice exhibiting primary 4TI mammary carcinoma in the left hind leg and lung metastases. Tumor accumulation was monitored by CT. Subsequently, 10 or 20 Gy 60Co γ-radiation was administered to primary tumors and lung metastasis. In session two, 1 × 1010 nanocapsules were injected i.v. and allowed to interact with P-selectin for 24 h; a further 10 or 20 Gy 60Co γ-radiation was administered to tumors and lung metastasis. In session one, CT imaged the accumulation of anti-VEGFR-1/2 nanocapsules around primary and metastatic tumors, which helped determine the timing of the first radiation. The nanocapsules released P-selectin and IFN γ in response to first radiation. P-selectin was deposited on tumor vessels. Radiation and released IFN γ elicited MHC-I and II on tumor cells and DCs. In session two, released CAND1 and ADGRF5-II from PLGA particle, which were emitted from nanocapsules upon second radiation, were loaded onto MHC-I and II. Subsequently, two kinds of tertiary complex were formed on tumor cells and DC: 1) MHC-I-CAND1-CD8+T-cell receptor (TCR); and 2) MHC-II- ADGRF5-II-CD4+TCR, which destroyed tumor cells, in collaboration with released PD-L1 Ab. Those T-cell mediated cell killing was magnified via enhanced DC-mediated T-cell priming by the two kinds of tertiary complex on DC. Those treatments resulted in EF 1.5 and 86% reduction of new metastasis formation. Our encapsulated pubic neoantigen particle will lead to quick and effective neoantigen immunotherapy.

Indigenous and commercial isolates of arbuscular mycorrhizal fungi display differential effects in Pyrus betulaefolia roots and elicit divergent transcriptomic and metabolomic responses.

Arbuscular mycorrhizal fungi (AMF) are beneficial soil fungi which can effectively help plants with acquisition of mineral nutrients and water and promote their growth and development. The effects of indigenous and commercial isolates of arbuscular mycorrhizal fungi on pear (Pyrus betulaefolia) trees, however, remains unclear. Trifolium repens was used to propagate indigenous AMF to simulate spore propagation in natural soils in three ways: 1. the collected soil was mixed with fine roots (R), 2. fine roots were removed from the collected soil (S), and 3. the collected soil was sterilized with 50 kGy 60Co γ-radiation (CK). To study the effects of indigenous AMF on root growth and metabolism of pear trees, CK (sterilized soil from CK in T. repens mixed with sterilized standard soil), indigenous AMF (R, soil from R in T. repens mixed with sterilized standard soil; S, soil from S in T. repens mixed with sterilized standard soil), and two commercial AMF isolates (Rhizophagus intraradices(Ri) and Funneliformis mosseae (Fm)) inoculated in the media with pear roots. Effects on plant growth, root morphology, mineral nutrient accumulation, metabolite composition and abundance, and gene expression were analyzed. AMF treatment significantly increased growth performance, and altered root morphology and mineral nutrient accumulation in this study, with the S treatment displaying overall better performance. In addition, indigenous AMF and commercial AMF isolates displayed common and divergent responses on metabolite and gene expression in pear roots. Compared with CK, most types of flavones, isoflavones, and carbohydrates decreased in the AMF treatment, whereas most types of fatty acids, amino acids, glycerolipids, and glycerophospholipids increased in response to the AMF treatments. Further, the relative abundance of amino acids, flavonoids and carbohydrates displayed different trends between indigenous and commercial AMF isolates. The Fm and S treatments altered gene expression in relation to root metabolism resulting in enriched fructose and mannose metabolism (ko00051), fatty acid biosynthesis (ko00061) and flavonoid biosynthesis (ko00941). This study demonstrates that indigenous AMF and commercial AMF isolates elicited different effects in pear plants through divergent responses from gene transcription to metabolite accumulation.

Dendrobium officinale Endophytes May Colonize the Intestinal Tract and Regulate Gut Microbiota in Mice.

Dendrobium officinale is a traditional Chinese medicine for treating gastrointestinal diseases by nourishing “Yin” and thickening the stomach lining. To study whether D. officinale endophytes can colonize the intestinal tract and regulate gut microbiota in mice, we used autoclave steam sterilizing and 60Co-γ radiation to eliminate D. officinale endophytes from its juice. Then, high-throughput ITS1-ITS2 rDNA and 16S rRNA gene amplicons were sequenced to analyze the microbial community of D. officinale endophytes and fecal samples of mice after administration of fresh D. officinale juice. Sterilization of D. officinale juice by autoclaving for 40 min (ASDO40) could more effectively eliminate the D. officinale endophytes and decrease their interference on the gut microbiota. D. officinale juice could increase beneficial gut microbiota and metabolites including short-chain fatty acids. D. officinale endophytes Pseudomonas mosselii, Trichocladium asperum, Titata maxilliformis, Clonostachys epichloe, and Rhodotorula babjevae could colonize the intestinal tract of mice and modulate gut microbiota after oral administration of the juice for 28 days. Thus, the regulatory effect of D. officinale juice on gut microbiota was observed, which provides a basis for inferring that D. officinale endophytes might colonize the intestinal tract and participate in regulating gut microbiota to treat diseases. Thus, this study further provides a new approach for the treatment of diseases by colonizing plant endophytes in the intestinal tract and regulating gut microbiota.

Characteristics and radiolysis behavior of polyvinylchloride under accelerated proton and γ-irradiation

The effect of high energy protons and γ-irradiation on the structural properties, surface-energies, and toxicological properties of polyvinyl chloride (PVC) were studied due to the role PVC products play in many technologies including the nuclear industry. Accelerated 1–4 MeV protons impacting on PVC in vacuum lead to the formation of polyenyl radicals as shown by EPR and to an increase in free surface energy due to functionalization of the surface of the irradiated polymer. γ-irradiation leads to the formation of unsaturated bonds, carbonyl and hydroxyl groups as shown by IR and to the release of HCl. Correlated molecular orbital theory calculations of reaction thermodynamics were used to aid in the development of a mechanism in the absence of oxygen. The formation and accumulation of chromophores and auxochromic groups during γ-radiolysis of PVC leads to a gradual change of the initial white color of the polymer to yellow and then to brown and black with high sensitivity. A mixture of powdered PVC and silicate glue was used to determine the profile of a 60Co γ-radiation beam on targets with a complex relief. γ-irradiated polymer does not have a local irritating effect due to a single application to the skin of mice in an adhesive mixture at a concentration of up to 5000 mg/kg. γ-radiolysis of PVC powder in air with a dose of up to 1400 kGy does not affect its acute toxicity when administered intragastrically to BDF1 mice. PVC and its γ-irradiated analogs are non-toxic at doses ≤5000 mg/kg.

Dose Field Shaping and Biological Effectiveness of the Effect of Pulsed Electron Accelerator Novac-11 on Mammalian Cells

The development of technologies for using the Novac-11 pulsed electron accelerator in radiation therapy of animals with spontaneous neoplasms requires dosimetric and radiobiological studies. The studies were performed on cultured Chinese hamster V-79 fibroblasts after irradiation with 10 MeV electrons in a dose range up to 12 Gy and 60Co γ-radiation. Chemical dosimeters FBX and Fricke were used as additional test-systems. The depth dose curves were measured and the maximum dose depth of the electron beam was determined in tissue-equivalent phantoms. Cell survival and the data of chemical dosimetric systems showed that the effects of electron irradiation did not differ from that of 60Co γ-radiation. It was concluded that the use of Novac-11 in the therapy of animals with spontaneous neoplasms is advisable.

Transcriptome analysis of pod mutant reveals plant hormones are important regulators in controlling pod size in peanut (Arachis hypogaea L.).

Pod size is an important yield-influencing trait in peanuts. It is affected by plant hormones and identifying the genes related to these hormones may contribute to pod-related trait improvements in peanut breeding programs. However, there is limited information on the molecular mechanisms of plant hormones that regulate pod size in peanuts. We identified a mutant with an extremely small pod (spm) from Yuanza 9102 (WT) by 60Co γ-radiation mutagenesis. The length and width of the natural mature pod in spm were only 71.34% and 73.36% of those in WT, respectively. We performed comparative analyses for morphological characteristics, anatomy, physiology, and global transcriptome between spm and WT pods. Samples were collected at 10, 20, and 30 days after peg elongation into the soil, representing stages S1, S2, and S3, respectively. The differences in pod size between WT and spm were seen at stage S1 and became even more striking at stages S2 and S3. The cell sizes of the pods were significantly smaller in spm than in WT at stages S1, S2, and S3. These results suggested that reduced cell size may be one of the important contributors for the small pod in spm. The contents of indole-3-acetic acid (IAA), gibberellin (GA), and brassinosteroid (BR) were also significantly lower in spm pods than those in WT pods at all three stages. RNA-Seq analyses showed that 1,373, 8,053, and 3,358 differently expressed genes (DEGs) were identified at stages S1, S2, and S3, respectively. Functional analyses revealed that a set of DEGs was related to plant hormone biosynthesis, plant hormone signal transduction pathway, and cell wall biosynthesis and metabolism. Furthermore, several hub genes associated with plant hormone biosynthesis and signal transduction pathways were identified through weighted gene co-expression network analysis. Our results revealed that IAA, GA, and BR may be important regulators in controlling pod size by regulating cell size in peanuts. This study provides helpful information for the understanding of the complex mechanisms of plant hormones in controlling pod size by regulating the cell size in peanuts and will facilitate the improvement of peanut breeding.

Identification and Characterization of a Mutant PV-PUR Gene Responsible for the Purple Phenotype of Snap Bean (Phaseolus vulgaris L.).

Pod color is a major economic trait of snap beans (Phaseolus vulgaris L.), among which the pod with a purple stripe is more attractive to people. A stable purple mutant with purple stripes on the pods was obtained by artificial mutagenesis with the high generation snap bean inbred line ‘A18-1’. In order to reveal the genetic factors and pathways responsible for the purple appearance in snap bean, we performed transcriptome and metabolome analyses using the green stem and yellow pod cultivar ‘A18-1’ and its purple mutant ‘pv-pur’ via 60Co-γ radiation. Transcriptome analysis showed that three genes in the anthocyanin biosynthetic pathway were differentially expressed, among which the expression level of F3′5′H (Phvul.006G018800) was increased in the mutant ‘pv-pur’, while expression of F3′H (Phvul.004G021200) and ANS (Phvul.002G152700) was downregulated. Anthocyanin-targeted metabonomics analysis showed significant differences in the contents of 10 metabolites between the wild type and mutant plants. Combined analysis of transcriptome and metabolomics showed that one differential metabolite, delphinidin, was related to the differential expression of Phvul.006G024700, Phvul.002G152700, and Phvul.006G018800. Based on the levels of six anthocyanins in wild type and mutant plants, we speculative that the purple appearance of the mutant ‘pv-pur’ is caused by the increased expression of F3′5′H (Phvul.006G018800), the key enzyme in the transformation from dihydroflavanol (DHK) to dihydromyricetone (DHM) in the anthocyanin biosynthetic pathway. The results lay a foundation for further studies on the molecular mechanism of anthocyanin synthesis in snap bean, and provide a framework for breeding different colors of snap bean.

Traits Analysis of Offsprings Mutated by 60Co-γ Radiation in Iris hollandica

Traits Analysis of Offsprings Mutated by 60Co-γ Radiation in Iris hollandica

60Co-γ Radiation Alters Developmental Stages of Zeugodacus cucurbitae (Diptera: Tephritidae) Through Apoptosis Pathways Gene Expression.

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.

Nanopore detects γ-radiation inhibited HIV-1 protease activity

Inhibition of HIV-1 protease (PR) activity is realized by exposure to 60Co γ-radiation. The radiation effects on enzyme kinetics of HIV-1 PR are subsequently monitored using nanopore sensor. Substantial loss of proteolytic efficiency towards GagPol polypeptide is observed due to the radiation treatment. Results shows ~50% of GagPol polypeptide was not involved in HIV-1 PR proteolysis by exposure to ultra-low intensity of γ-radiation (0.1K Gy), and the values reach to over 90% with high γ-ray treatment. Besides, the inactivation effect is also verified in blood samples which contain the virus protease. Our finding provides the potential benefits of γ-radiation to inactivate viral proteinic function, and might be a complementary to the designation of HIV-1 PR inhibitors.