Insights from the annotated wheat genome Wheat is one of the major sources of food for much of the world. However, because bread wheat's genome is a large hybrid mix of three separate subgenomes, it has been difficult to produce a high-quality reference sequence. Using recent advances in sequencing, the International Wheat Genome Sequencing Consortium presents an annotated reference genome with a detailed analysis of gene content among subgenomes and the structural organization for all the chromosomes. Examples of quantitative trait mapping and CRISPR-based genome modification show the potential for using this genome in agricultural research and breeding. Ramírez-González et al. exploited the fruits of this endeavor to identify tissue-specific biased gene expression and coexpression networks during development and exposure to stress. These resources will accelerate our understanding of the genetic basis of bread wheat. Science, this issue p. eaar7191; see also p. eaar6089 Expression profiling of homoeologs (pairs of genes united by polyploidy) across tissues reveals expression asymmetry along wheat chromosomes. INTRODUCTION Polyploidy, arising from whole-genome duplication or interspecific hybridization, is ubiquitous across the plant and fungal kingdoms. The presence of highly related genes in polyploids, referred to as homoeologs, has been proposed to confer adaptive plasticity—for example, through neofunctionalization of duplicated genes or tissue-specific expression. This plasticity has facilitated the domestication and adaptation of major polyploid crops (e.g., wheat, cotton, and coffee). However, despite its likely importance, we have a limited understanding of the effect of polyploidy on gene expression and the extent to which homoeologs are similar or different in their expression patterns across development and tissues. RATIONALE Bread wheat is a polyploid derived from the hybridizations between three distinct diploid species and is an informative system for analyzing the effects of recent polyploidy on gene expression. Understanding the coordination of homoeologs and identifying the mechanisms associated with these processes should help define strategies to improve trait biology in a crop that provides more than 20% of the protein and caloric intake of humans. RESULTS Here we leverage 850 wheat RNA-sequencing samples, alongside the annotated genome, to determine the similarities and differences between homoeolog expression across a range of tissues, developmental stages, and cultivars. On average, ~30% of wheat homoeolog triads (composed of A, B, and D genome copies) showed nonbalanced expression patterns, with higher or lower expression from a single homoeolog with respect to the other two. These differences between homoeologs were associated with epigenetic changes affecting DNA methylation and histone modifications. Although nonbalanced homoeolog expression could be partially predicted by expression in diploid ancestors, large changes in relative homoeolog expression were observed owing to polyploidization. Our results suggest that the transposable elements in promoters relate more closely to the variation in the relative expression of homoeologs across tissues than to a ubiquitous effect across all tissues. We found that homoeologs with the highest inter-tissue variation had promoters with more frequent transposable element insertions and more varied cis-regulatory elements than homoeologs that were stable across tissues. We also identified expression asymmetry along wheat chromosomes. Homoeologs with the largest inter-tissue, inter-cultivar, and coding sequence variation were most often located in the highly recombinogenic distal ends of chromosomes. These transcriptionally dynamic homoeologs are under more relaxed selection pressure, potentially representing the first steps toward functional innovation through neo- or subfunctionalization. We generated tissue- and stress-specific coexpression networks that reveal extensive coordination of homoeolog expression throughout development. These networks, alongside detailed gene expression atlases (www.wheat-expression.com and http://bar.utoronto.ca), lay the groundwork to identify candidate genes influencing agronomic traits in wheat. CONCLUSION This study provides detailed insights into the transcriptional landscape of bread wheat, an evolutionarily young polyploid. Our work shows that homoeolog expression patterns in bread wheat have been shaped by polyploidy and are associated with both epigenetic modifications and variation in transposable elements within promoters of homoeologous genes. The extensive datasets and analyses presented here provide a framework that can help researchers and breeders develop strategies to improve crops by manipulating individual or multiple homoeologs to modulate trait responses. Homoeolog expression patterns in polyploid wheat. Seventy percent of triads (A, B, and D homoeologs) show balanced expression among homoeologs and are ubiquitously expressed (left), whereas ~30% show nonbalanced expression and are more tissue-specific (right; symbolized by three exemplar tissues). Variation in promoter elements and nonsynonymous substitution rates distinguish between individual triads with stable relative expression across tissues and triads with more inter-tissue variation (tissue-dynamic triads). The coordinated expression of highly related homoeologous genes in polyploid species underlies the phenotypes of many of the world’s major crops. Here we combine extensive gene expression datasets to produce a comprehensive, genome-wide analysis of homoeolog expression patterns in hexaploid bread wheat. Bias in homoeolog expression varies between tissues, with ~30% of wheat homoeologs showing nonbalanced expression. We found expression asymmetries along wheat chromosomes, with homoeologs showing the largest inter-tissue, inter-cultivar, and coding sequence variation, most often located in high-recombination distal ends of chromosomes. These transcriptionally dynamic genes potentially represent the first steps toward neo- or subfunctionalization of wheat homoeologs. Coexpression networks reveal extensive coordination of homoeologs throughout development and, alongside a detailed expression atlas, provide a framework to target candidate genes underpinning agronomic traits in wheat.
Iulian Andreicovici, Radu Seremet, Silvia Ise
et al.
Gamma spectra analysis is a key component for most environmental research programs. The TENORM nuclide evaluation is essential for mapping natural and artificial radioactivity, whether conducted in situ or in laboratory experiments, and the results support a wide range of interdisciplinary investigations. Preparation protocols are well established and straightforward, and hardware tools are increasingly robust and reliable. Numerous versatile software tools are available to complement the experimental inventory, enabling precise data acquisition. However, precision is sometimes debatable due to complicated algorithms, forced correlations, or references to unadapted libraries. To address pivotal environmental requirements and embrace simplicity as an ally, we present GaDeTool Geo, an algorithm and associated software developed for the automatic calibration of spectra, with emphasis on detectors that provide a quasi-linear response to energy. Provided the spectrum includes at least a natural component or background, calibration and analysis proceed in the most minimalist and natural way possible. A variety of customizations are being implemented in the online version, which will soon evolve into an application facilitating in situ analysis. In the meantime, GaDeTool Geo has been tested against commercial software, delivering reliable output by minimizing coincidence, scattering, and, where possible, self-attenuation effects.
Radon, a radioactive gas, poses a significant health risk when accumulated in indoor environments. This study measured radon concentrations in three rooms with varying ventilation levels over a 12-month period, utilizing a Corentium monitor, an alpha spectroscopy-based radon detection device. The objective was to assess the impact of seasonal variations on indoor radon levels. The results indicated that the highest radon concentration, approximately 42 Bqm-3, was consistently observed in the closed room. In comparison, the partially closed room and the regularly occupied room with normal ventilation, had concentrations of 35 Bqm-3 and 31 Bqm-3, respectively. Across all three rooms, radon levels were lowest during the summer and peaked during the winter. The dose and risk associated with radon exposure were further analyzed using the RESRAD-BUILD computer code. All measured radon levels and associated doses were below the global safety limits. This study highlights the critical role of ventilation in controlling indoor radon levels and confirms that the environments studied remain within safe exposure thresholds.
This study evaluates current radiological disaster response manuals for resident protection near nuclear power plants in the Republic of Korea, a crucial aspect of radiological emergency preparedness. The research identifies strategies for improvement based on data collected from emergency responders in nuclear power plant-adjacent regions using a survey question- naire grounded in resilience engineering principles. Key focus areas include environmental and social factor analysis, manual standardization, shelter optimization and scenario develop- ment for vulnerable groups. The study recommends redistributing responsibilities across government levels, improving communication channels, maintaining expertise in emergency preparedness, and providing local governments with adequate financial and human resources to implement these enhancements effectively.
Aleksandar Ivkovic, Srecko Ilic, Radovan Radovanovic
et al.
This research deals with the assessment of the risk to which air traffic is exposed in zones of increased level of radioactive radiation. Natural disasters and war conflicts, which take place around nuclear power plants and the radioactive area (Chernobyl), create fear that large amounts of radioactive material may be released into the atmosphere. The paper analyzed the effects of: the efficiency of the HEPA filter in relation to the size of the radioactive dust particles, radioactivity on the aircraft instrumentation, radioactivity on the engine and the contribution of the engine in the spread of radioactivity to the crew in the aircraft. An assessment of the risk of exposure to radioactive radiation in the aircraft was put in perspective, depending on the type of aircraft and the dose of radiation.
Yehia Abbas, Ahmed El-Khatib, Mohamed Badawi
et al.
Polymer composites of polyvinyl chloride, PVC, were loaded up with micro and nano PbO/CuO particles. The added percentage of each by mass was 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.%, plus 40 wt.% of mixed composite (20 wt.% CuO + 20 wt.% PbO). The mass and linear attenuation coefficients of the investigated composites were measured as a function of gamma-ray energies going from 59.53 keV to 1408.01 keV utilizing standard radioactive point sources. To confirm the validity of these results the attenuation coefficients for bulk composites (PVC + PbO and PVC + CuO) were calculated by using the XCOM software. The results were in good agreement with the values obtained from the experimental work. By comparing the attenuation coefficients of the different composites it was found that those loaded with either nano PbO or CuO have higher values than those loaded with bulk sizes with the same percentage. Also, samples loaded with nano PbO have the highest attenuation coefficients even by comparing them with (20 wt.% CuO + 20 wt.% PbO), especially in the energy region below 1 MeV, but for greater energies, the values become very closed. The investigation of the mechanical properties of such composites due to the injection of bulk and nano metals reveals that tensile strength and Young's modulus of PVC nanocomposite sheets were notably increased with the increasing concentration of CuO and PbO nanoparticles. The CuO nanocomposite showed the highest values of flexural strength, toughness, and tensile strength among all the fabricated nanocomposite sheets.
Leila Ramezani, Masoud Mansouri, Mohammad Rahgoshay
Zirconium alloys, are usually used as fuel cladding materials in VVER (water-cooled, water-moderated energy reactor) type reactors, mainly, due to their low neutron absorption cross-section, desirable mechanical properties, and good corrosion resistance under reactor operating conditions. During exposure to water at high temperature, water reacts with zirconium alloys, which results in the production of an oxide layer. The entire area of corrosion along with the accompanying absorption of hydrogen in the zirconium metal matrix has attracted a lot of attention when the performance of the core components as well as the operation of the reactor is emphasized. The growth of the zirconium oxide layer plays a destructive role in decreasing thermal efficiency of the reactor by restricting the inlet temperature and chemical properties of the coolant. The present study aimed to develop a computer code to predict long-term water side corrosion weight gain, oxide thickness and determine the concentration of absorbed hydrogen in VVER-1000 reactors during normal operating conditions. The proposed model can be utilized to estimate the pre-transition and post-transition corrosion weight gain and the oxide thickness in operating conditions.
Luciferases are widely used to monitor biological processes. Here we describe the naturally secreted Gaussia princeps luciferase (Gluc) as a highly sensitive reporter for quantitative assessment of cells in vivo by measuring its concentration in blood. The Gluc blood assay complements in vivo bioluminescence imaging, which has the ability to localize the signal and provides a multifaceted assessment of cell viability, proliferation and location in experimental disease and therapy models.
Calibrations of neutron devices used in area monitoring are often performed by radionuclide neutron sources. Device readings increase due to neutrons scattered by the surroundings and the air. The influence of said scattering effects have been investigated in this paper by performing Monte Carlo simulations for ten different radionuclide neutron sources inside several sizes of concrete wall spherical rooms (Rsp = 200 to 1500 cm). In order to obtain the parameters that relate the additional contribution from scattered neutrons, calculations using a polynomial fit model were evaluated. Obtained results show that the contribution of scattering is roughly independent of the geometric shape of the calibration room. The parameter that relates the room-return scattering has been fitted in terms of the spherical room radius, so as to reasonably accurately estimate the scattering value for each radionuclide neutron source in any geometry of the calibration room.