Vicia Faba Root Research Articles

Oxidative replication stress induced by long-term exposure to hydroxyurea in root meristem cells of Vicia faba.

Low concentrations of hydroxyurea, an inhibitor of DNA replication, induced oxidative and replicative stress in root apical meristem (RAM) cells of Vicia faba. Plant cells are constantly exposed to low-level endogenous stress factors that can affect DNA replication and lead to DNA damage. Long-term treatments of Vicia faba root apical meristems (RAMs) with HU leads to the appearance of atypical cells with intranuclear asynchrony. This rare form of abnormality was manifested by a gradual condensation of chromatin, from interphase to mitosis (so-called IM cells). Moreover, HU-treated root cells revealed abnormal chromosome structure, persisting DNA replication, and elevated levels of intracellular hydrogen peroxide (H2O2) and superoxide anion (O2∙-). Immunocytochemical studies have shown an increased number of fluorescent foci of H3 histones acetylated at lysine 56 (H3K56Ac; canonically connected with the DNA replication process). We show that continuous 3-day exposure to low concentrations (0.75mM) of hydroxyurea (HU; an inhibitor of DNA replication) induces cellular response to reactive oxygen species and to DNA replication stress conditions.

Micronucleus Induction in Vicia faba Root Tips by Crude Oil-Polluted Soil from Ecuadorian Amazon

In the past four decades, the Amazon rainforest has emerged as a crucial zone for crude oil extraction in the South American region. In the Ecuadorian Amazon rainforest, hydrocarbon blocks (called “bloques”) cover vast zones, including agricultural and livestock farms, protected natural regions and the territories of uncontacted indigenous tribes. This study proposes a micronuclei assay on Vicia faba following a 24 h exposure to various soil samples collected from Bloque 57 in Ecuador. Sampling was conducted between the Dayuma and Aguarico zones, approximately 30 km from Nueva Loja city. The research aimed to assess the impact of different soil samples, particularly those from areas affected by crude oil spills, to induce micronuclei and mitotic index changes in V. faba roots. Results: The soil pollution caused by crude oil is not the sole factor contributing to cytotoxicity and genotoxicity in V. faba. Most samples from areas polluted by crude oil outside the small-scale farm showed no significant difference in micronuclei rate compared to negative control and Amazon unpolluted soil. Conversely, samples from the small-scale farm displayed a statistically significant genotoxic effect. Furthermore, samples collected from open-air wastewater pools demonstrated higher levels of cytotoxicity compared to the controls and those from small-scale farms. The mitotic index was lower in seedlings exposed to wastewater in open-air pools, especially for the 20 cm deep samples. This phenomenon could be linked to bitumen-like substances and oils floating on the surface, attaching to the small roots and causing suffocation.

Epigenetic modifications evidenced by isolation of proteins on nascent DNA and immunofluorescence in hydroxyurea-treated root meristem cells of Vicia faba

Main conclusionBy implementation of the iPOND technique for plant material, changes in posttranslational modifications of histones were identified in hydroxyurea-treated root meristem cells of Vicia. Replication stress (RS) disrupts or inhibits replication forks and by altering epigenetic information of the newly formed chromatin can affect gene regulation and/or spatial organisation of DNA. Experiments on Vicia faba root meristem cells exposed to short-term treatment with 3 mM hydroxyurea (HU, an inhibitor of DNA replication) were aimed to understand epigenetic changes related to RS. To achieve this, the following histone modifications were studied using isolation of proteins on nascent DNA (iPOND) technique (for the first time on plant material) combined with immunofluorescence labeling: (i) acetylation of histone H3 at lysine 56 (H3K56Ac), (ii) acetylation of histone H4 at Lys 5 (H4K5Ac), and (iii) phosphorylation of histone H3 at threonine 45 (H3T45Ph). Certainly, the implementation of the iPOND method for plants may prove to be a key step for a more in-depth understanding of the cell's response to RS at the chromatin level.

Magnesium oxyhydroxide nanoparticles: Synthesis, characterization and evaluation of their genotoxicity in Vicia faba L.

Magnesium oxyhydroxide nanoparticles (MgO/Mg(OH)2-NPs) were synthesized by a chemical route and their toxicity were evaluated using Vicia faba L. The obtained solids were characterized using visible infrared and ultraviolet spectroscopy, X-ray diffraction (XRD), electron microscopy and surface area by the BET method. The results indicated the presence of two phases: periclase (MgO) and brucite (Mg(OH)2). These MgO/Mg(OH)2 were <50 nm in size, with band gap energy between 5.95 and 6.12 eV and Urbach energy of ∼340 meV. To determine toxicological endpoints, such as mitotic index (MI) and micronucleus induction (MN), Vicia faba L. root tip cells were treated with suspensions containing concentrations of 12.5, 25, 50 and 100 mg/L of MgO/Mg(OH)2-NPs. The results of the toxicological evaluation showed a decrease in MI in the roots of Vicia faba L. exposed to NPs and a positive correlation between the percentage of cells with MN and the concentrations of MgO/Mg(OH)2-NPs used.

O2 plasma-modified carbon nanotube for sulfamethoxazole degradation via peroxymonosulfate activation: Synergism of radical and non-radical pathways boosting water decontamination and detoxification

Sulfamethoxazole (SMX), a widely used antibiotic, has triggered increasing attention due to its extensive detection in wastewater effluent, causing serious ecological threats. Herein, a carbon-based heterogeneous catalyst was developed by the O2 plasma-etching process, regulating oxygen-containing functional groups (OFGs) and defects of carbon nanotubes (O-CNT) to activate peroxymonosulfate (PMS) for highly efficient SMX abatement. Through adjusting the etching time, the desired active sites (i.e., C=O and defects) could be rationally created. Experiments collectively suggested that the degradation of SMX was owing to the contribution of synergism by radical (•OH (17.3%) and SO4•– (39.3%)) and non-radical pathways (1O2, 43.4%), which originated from PMS catalyzed by C=O and defects. In addition, the possible degradation products and transformation pathways of SMX in the system were inferred by combining the Fukui function calculations and the LC-MS/MS analysis. And the possible degradation pathway was effective in reducing the environmental toxicity of SMX, as evidenced by the T.E.S.T. software and the micronucleus experiment on Vicia faba root tip. Also, the catalytic system exhibited excellent performance for different antibiotics removal, such as amoxicillin (AMX), carbamazepine (CBZ) and isopropylphenazone (PRP). This study is expected to provide an alternative strategy for antibiotics removal in water decontamination and detoxification.

Cytotoxicity and genotoxicity evaluation of chloroform using Vicia faba roots.

Chloroform is a widely used industrial chemical that can also pollute the environment. The aims of this study were to examine the potential cytotoxicity and genotoxicity of chloroform on plant cells, using the Vicia faba bioassay. Chloroform was evaluated at concentrations of 0.1, 0.5, 1, 2, and 5mg·L-1. The following parameters were analyzed: the mitotic index (MI), micronucleus (MN) frequency, chromosomal aberration (CA) frequency, and malondialdehyde (MDA) content. The results showed that exposure to increasing concentrations of chloroform caused a decrease in MI and an increase in the frequency of MN in Vicia faba root tip cells, relative to their controls. Moreover, various types of CA, including C-mitosis, fragments, bridges, laggard chromosomes, and multipolar mitosis, were observed in the treated cells. The frequency of MN was positively correlated with the frequency of CA in exposure to 0.1-1mg·L-1 chloroform. Furthermore, chloroform exposure induced membrane lipid peroxidation damage in the Vicia faba radicle, and a linear correlation was observed between the MDA content and the frequency of MN or CA. These findings indicated that chloroform exposure can result in oxidative stress, cytotoxicity, and genotoxicity in plant cells.

Hormonal crosstalk controls cell death induced by kinetin in roots of Vicia faba ssp. minor seedlings

Studies of vitality/mortality of cortex cells, as well as of the concentrations of ethylene (ETH), gibberellins (GAs), indolic compounds/auxins (ICs/AUXs) and cytokinins (CKs), were undertaken to explain the hormonal background of kinetin (Kin)-regulated cell death (RCD), which is induced in the cortex of the apical parts of roots of faba bean (Vicia faba ssp. minor) seedlings. Quantification was carried out with fluorescence microscopy, ETH sensors, spectrophotometry and ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC‒MS/MS). The results indicated that Kin was metabolized to the transport form, i.e., kinetin-9-glucoside (Kin9G) and kinetin riboside (KinR). KinR was then converted to cis-zeatin (cZ) in apical parts of roots with meristems, to cis-zeatin riboside (cZR) in apical parts of roots without meristems and finally to cis-zeatin riboside 5’-monophosphate (cZR5’MP), which is indicated to be a ligand of cytokinin-dependent receptors inducing CD. The process may be enhanced by an increase in the amount of dihydrozeatin riboside (DHZR) as a byproduct of the pathway of zeatin metabolism. It seems that crosstalk of ETH, ICs/AUXs, GAs and CKs with the cZR5’MP, the cis-zeatin-dependent pathway, but not the trans-zeatin-dependent pathway, is responsible for Kin-RCD, indicating that the process is very specific and offers a useful model for studies of CD hallmarks in plants.

Resolving dynamic mineral-organic interactions in the rhizosphere by combining in-situ microsensors with plant-soil reactive transport modeling

Associations between minerals and organic matter represent one of the most important carbon storage mechanisms in soils. Plant roots are major sources of soil carbon, and resolving the dynamics and dominance of microbial consumption versus mineral sorption of root-derived carbon is critical to understanding soil carbon storage. Here we integrate in-situ rhizosphere microsensor and plant physiological measurements with a 3-D plant-soil reactive transport model to explore the fate of dissolved organic carbon (DOC) in the rhizosphere, particularly its microbial consumption and interaction with Fe oxide minerals. Over several days, microdialysis probes at the root-soil interface of growing Vicia faba roots in live soil, revealed clear diel patterns of DOC concentration in the pore water. Daytime DOC spikes coincided with peaks in leaf-level photosynthesis rates and were accompanied by declining redox potential and dissolved oxygen as well as increasing pH in the rhizosphere. Incorporating microsensor data into our modeling framework showed that the measured rapid loss of DOC after each mid-day spike could not be explained by consumption via aerobic respiration, nor via anaerobic respiration dominated by Fe oxide reduction. Rather, in the model, a large fraction of rhizosphere DOC was rapidly immobilized each day by adsorption to Fe oxides. Further, modeled microbial Fe reduction (fueled by DOC) did not mobilize significant organic carbon from Fe oxides during the day. Instead, the model predicted equilibrium desorption of organic carbon from Fe oxides at night. This new mechanistic modeling framework, which couples aboveground plant physiological measurements with non-destructive high-resolution monitoring of rhizosphere processes, has great potential for exploring the dynamics and balance of the various microbial reactions and mineral interactions controlling carbon storage in soils.

Fungal Strain as Biological Tool to Remove Genotoxicity Effect of Phenolic Compounds from Olive Mill Wastewater

This study aims to select fungi isolates to reduce olive mill wastewater (OMWW) chemical oxygen demand (COD) and phenolic compounds (PC), as well as their genotoxicity effect. Treatment with mold, isolated by an innovative technique using phenolic compound-selective media, showed a reduction rate of about 4% for COD and 2% for PC during one month of incubation without optimization of the treatment conditions. Whereas this percentage reached 98% and 96% for COD and PC, respectively, after only 12 days of treatment, when the C:N ratio was adjusted to 30 by adding urea as a nitrogen source at 150 rpm agitation speed. Genetic sequence homology of the most efficient mold isolate showed 100% similarity to Penicillium chrysogenum. High-performance liquid chromatography analysis of phenolic extracts of untreated OMWW showed the presence of five compounds—hydroxytyrosol at 1.22 g.L−1, tyrosol at 0.05 g.L−1, caffeic acid at 0.16 g.L−1, p-coumaric acid at 0.05 g.L−1 and oleuropein at 0.04 g.L−1—that were eliminated during the degradation process at 88.82%. Genotoxicity, assessed by the Vicia-faba root cell, showed a significant decrease in micronucleus frequency of about 96% after fungal treatment. These results confirm the positive role of fungal treatment of OMWW to eliminate genotoxicity and their ability to improve the agronomic potential.

Toxic effects of chemical plant residues on soil

Soil samples were collected from 6 different areas of the abandoned pesticide factory site, numbered p1, p2, p3, p4, p5, and p6, respectively. Based on the acute toxicity of Luminescent bacteria and Flea and the genotoxicity of Vicia faba root tip micronucleus, the ecotoxicological diagnosis of soil extracts from 6 samples was carried out. The results showed that the relative luminosity of the 6 kinds of extracts to luminescent bacteria were 50.7%, 56.3%, 43.7%, 53.0%, 49.6% and 67.6%, respectively. The 48-hour acute toxicity EC50 of the large flea was 6.15%, 8.65%, 0.57%, 2.52%, 0.33% and 14.94%, respectively. The results of the photobacterial experiment were basically consistent with the acute toxicity results of Flea daphnia, and the results showed that the soil pollution of the pesticide factory site was relatively serious.

Response of Vicia faba to short-term uranium exposure: chelating and antioxidant system changes in roots.

Uranium (U) phytotoxicity is an inherently difficult problem in the phytoremediation of U-contaminated environments. Plant chelating and antioxidant systems play an authoritative role in resistance to abiotic stress. To reveal the toxicity of U, the changes of chelating system, osmoregulatory substances and antioxidant systems in Vicia faba roots were studied after short-term (24h) U exposure. The results indicated that the development of lateral roots and root activity of V. faba were significantly inhibited with U accumulation. Compared with the control, plant chelating systems showed significant positive effects after U exposure (15 - 25μM). Osmoregulatory substances (proline and soluble protein) increasingly accumulated in roots with increasing U concentration, and O2- and H2O2 rapidly accumulated after U exposure (15 - 25μM). Thus, the contents of malondialdehyde (MDA), a marker of lipid peroxidation, were also significantly increased. Antioxidant systems were activated after U exposure but were inhibited at higher U concentrations (15 - 25μM). In summary, although the chelating, osmotic regulation and antioxidant systems in V. faba were activated after short-term U exposure, the antioxidases (CAT, SOD and POD) were inhibited at higher U concentrations (15 - 25μM). Therefore, the root cells were severely damaged by peroxidation, which eventually resulted in inhibited activity and arrested root development.

Uranium triggers ferroptosis-like cell death in Vicia faba roots by increasing iron accumulation and inhibiting glutathione peroxidase activity

Uranium (U) is a non-essential and toxic element that can cause cell death in plants, but the mechanism is unclear. In the present study, we found that U triggered iron (Fe)- and reactive oxygen species (ROS)-dependent ferroptosis-like cell death in Vicia faba roots. The results showed that U entered V. faba root cells and even accumulated in the nucleus and organelles. U accumulation resulted in obvious changes in mitochondrial morphology, including shrunken shape, rupture of outer membrane, increased density of inner membrane and fuzzy crista. Compared with the control, the accumulation of Fe and ROS in V. faba roots increased after U exposure, while the peroxidase (POD) and glutathion peroxidase (GPX) activities decreased significantly, which was only 57.7% and 14.3% of control, respectively. Transcriptomic data showed that the expression of genes related to ROS production was mainly up-regulated (e.g. NDH , CCR , RbohB ), while the expression of genes related to ROS scavenging was mainly down-regulated (e.g. GPX4 , POD1 , POD7 ). These results led to excessive accumulation of ROS in root cells and triggered ferroptosis-like cell death. The key mechanism of U triggering ferroptosis-like cell death was to increase Fe accumulation and decrease GPX activity, so the cell death was promoted by addition of Fe (FeSO 4 and FeCl 3 ), and was inhibited by the lipophilic antioxidants [ferrostatin (Fer-1) and Vitamin E (VE)] and the Fe chelators [ciclopirox olamine (CPX)]. In conclusion, we demonstrated for the first time that U triggered ferroptosis-like cell death in V. faba roots. Our results provide a new insight for revealing the toxicological mechanism of U and other heavy metals in plants. • Uranium triggered ferroptosis-like cell death in Vicia faba roots. • Uranium accumulated in the nucleus and organelles after entering root cells. • Uranium induced iron accumulation and lipid peroxidation in Vicia faba roots. • Uranium severely inhibited GPX4 expression and glutathione peroxidase activity.

Growth Performance and Nitrogen Fixing Efficiency of Faba Bean (Vicia faba L.) Genotypes in Symbiosis with Rhizobia under Combined Salinity and Hypoxia Stresses

The present study was carried out in order to investigate the behaviour of six faba bean (Vicia faba Minor) genotypes (Saber 02, Locale, Baachar, Badii, Chourouk and Najeh) in response to salinity and flooding (hypoxia), either alone or combined, to identify tolerant genotypes and to select efficient faba bean-rhizobia symbiosis under salinity and/or hypoxia conditions. faba bean genotypes were cultivated in three agricultural soils with either low (160 µs/cm) or moderate (1850 µs/cm) salt content and submitted or not to a 30-day long flooding period. Growth parameters and photosynthetic performance were analyzed at the end of the flowering period. At harvest time, the Najeh genotype showed the highest dry mass production in both control and hypoxia conditions (7.90 and 6.75 g/plant, respectively), whereas Saber 02 showed the lowest (3.75 and 2.25 g/plant, respectively). Differences between genotypes were less marked in salinity or combined salinity/flooding conditions. Principal component analysis of the analyzed parameters revealed that the Najeh genotype presents the best growth and the lowest photosynthetic perturbation and lipid peroxidation levels, whether under control or hypoxic conditions, whereas Saber 02 and Locale genotypes were less productive. Ninety bacteria strains were isolated from Vicia faba root nodules. Of these, 47 strains were identified as rhizobia, and 20 were able to re-nodulate the host plant. After the characterization, identification and selection process, four strains were selected as the best faba bean symbiotic partners based on their symbiotic efficiency and salt tolerance behaviours. Our results suggest that faba bean tolerant genotypes in symbiosis with these strains could be useful in enhancing legume cultivation under saline and hypoxia field conditions.

Changes in Epigenetic Patterns Related to DNA Replication in Vicia faba Root Meristem Cells under Cadmium-Induced Stress Conditions.

Experiments on Vicia faba root meristem cells exposed to 150 µM cadmium chloride (CdCl2) were undertaken to analyse epigenetic changes, mainly with respect to DNA replication stress. Histone modifications examined by means of immunofluorescence labeling included: (1) acetylation of histone H3 on lysine 56 (H3K56Ac), involved in transcription, S phase, and response to DNA damage during DNA biosynthesis; (2) dimethylation of histone H3 on lysine 79 (H3K79Me2), correlated with the replication initiation; (3) phosphorylation of histone H3 on threonine 45 (H3T45Ph), engaged in DNA synthesis and apoptosis. Moreover, immunostaining using specific antibodies against 5-MetC-modified DNA was used to determine the level of DNA methylation. A significant decrease in the level of H3K79Me2, noted in all phases of the CdCl2-treated interphase cell nuclei, was found to correspond with: (1) an increase in the mean number of intranuclear foci of H3K56Ac histones (observed mainly in S-phase), (2) a plethora of nuclear and nucleolar labeling patterns (combined with a general decrease in H3T45Ph), and (3) a decrease in DNA methylation. All these changes correlate well with a general viewpoint that DNA modifications and post-translational histone modifications play an important role in gene expression and plant development under cadmium-induced stress conditions.

Oxidation of pyrazolone pharmaceuticals by peracetic acid: Kinetics, mechanism and genetic toxicity variations

Peracetic acid (PAA) oxidation is an emerging technology in water disinfection and purification. This study evaluated the oxidation of three pyrazolone pharmaceuticals (i.e., Aminopyrine (AMP), Antipyrine (ANT), and Isopropylphenazone (PRP) by PAA. Experimental results showed that PAA exhibited structure selectivity to the above three pharmaceuticals and oxidized AMP with the highest reactivity. The degradation kinetics of AMP was investigated by calculating the apparent second-order rate constants (kapp) under different initial pH. Through kinetic simulation, the second-order rate constants of elementary reactions between AMP (i.e., neutral (AMP0) and protonated (AMP+) species) with PAA (i.e., neutral (PAA0) and anionic (PAA−) species) were obtained to be 0.34 ± 0.077 M−1 s−1(k”AMP+, PAA0), 0.89 ± 0.091 M−1 s−1(k”AMP0, PAA-) and 5.94 ± 0.142 M−1 s−1(k”AMP0, PAA0), respectively. The PAA could oxidize AMP via electrophilic attack, and the degradation site of AMP was confirmed to be the central nitrogen of –N(CH3)2 with the highest relative electrophilicity (sk-/sk+, 48.8614) by Density Functional Theory (DFT) calculation. The intermediates/products of AMP degradation were identified by high-performance liquid chromatography-mass spectrometry (LC-MS/MS), and the transformation pathways of AMP during PAA oxidation were inferred to be hydroxylation, demethylation, and CC cleavage. The genetic toxicity of AMP contaminated water could be reduced after PAA oxidation, which was evaluated by the micronucleus test of Vicia faba root tips.

Up-Regulated Salivary Proteins of Brown Marmorated Stink Bug Halyomorpha halys on Plant Growth-Promoting Rhizobacteria-Treated Plants.

Plant Growth-Promoting Rhizobacteria (PGPR) induce systemic resistance (SR) in plants, decreasing the development of phytopathogens. The FZB42 strain of Bacillus velezensis is known to induce an SR against pathogens in various plant species. Previous studies suggested that it could also influence the interactions between plants and associated pests. However, insects have developed several strategies to counteract plant defenses, including salivary proteins that allow the insect escaping detection, manipulating defensive pathways to its advantage, deactivating early signaling processes, or detoxifying secondary metabolites. Because Brown Marmorated Stink Bug (BMSB) Halyomorpha halys is highly invasive and polyphagous, we hypothesized that it could detect the PGPR-induced systemic defenses in the plant, and efficiently adapt its salivary compounds to counteract them. Therefore, we inoculated a beneficial rhizobacterium on Vicia faba roots and soil, previous to plant infestation with BMSB. Salivary gland proteome of BMSB was analyzed by LC-MS/MS and a label-free quantitative proteomic method. Among the differentially expressed proteins, most were up-regulated in salivary glands of insects exposed to PGPR-treated plants for 24h. We could confirm that BMSB was confronted with a stress during feeding on PGPR-treated plants. The to-be-confirmeddefensive state of the plant would have been rapidly detected by the invasive H. halys pest, whichconsequently modified its salivary proteins. Among the up-regulated proteins, many could be associated with a role in plant defense counteraction, and more especially in allelochemicals detoxification or sequestration.

Electrochemical activation of peroxymonosulfate (PMS) by carbon cloth anode for sulfamethoxazole degradation

Electrochemical activation of peroxymonosulfate (PMS) at carbon cloth anode (E (Carbon cloth Anode)/PMS system) was investigated for sulfamethoxazole (SMX) degradation. The results indicated that PMS could be activated at carbon cloth anode during electrolysis, resulting in the improvement of SMX degradation. The degradation efficiency of SMX was facilitated with the higher PMS concentration and current density, respectively. The degradation rate constant of SMX increased with the rising pH from 3.6 to 6.0, and reached the highest value at pH 6.0, and then decreased with further increasing pH to 8.0. The presence of chloride ion (Cl−, 5–100 mM) significantly enhanced SMX degradation, while addition of humic acid (HA, 1–5 mgC L−1) inhibited SMX degradation. Addition of carbonate (HCO3−, 5–20 mM) had a negligible impact on SMX degradation. Small amounts of phosphate (PO43−, 0–5 mM) could promote degradation, while a large amount of PO43− (10–20 mM) inhibited the degradation. Moreover, the quenching experiments demonstrated that sulfate radical (SO4·−), hydroxyl radical (·OH) and singlet oxygen (1O2) contributed to SMX degradation in E (Carbon cloth Anode)/PMS system. The degradation intermediates of SMX were identified by LC-MS/MS and the degradation pathways were deduced to be hydroxylation, the cleavage of S–N bond, and oxidation of aniline group. Moreover, the micronucleus test of Vicia faba root tips indicated that the E (Carbon Cloth Anode)/PMS system could reduce the genetic toxicity of SMX contaminated water to some extent.

Preliminary assessment of genotoxic effects induced by radiation from EAST using Vicia faba micronucleus assay

During long-pulse deuterium plasma operations in the Experimental Advanced Superconducting Tokamak (EAST), a mixed radiation field is generated, which is mainly composed of fusion neutrons, gamma rays, and x-rays. More accurate and effective dose monitoring methods have been developed and established to determine the ionizing radiation intensity both for the stable operation of the device and for the radiation safety of personnel. As far as we know, there are few reports about the biological effects of radiation induced by fusion neutrons and γ radiation, which are of vital importance for the assessment of radiation hazards presented by fusion devices, such as EAST, to human beings and the environment. In this study, three positions in the EAST hall were selected to detect genotoxic effects induced by nuclear fusion radiation using a Vicia faba micronucleus (MN) test for the first time. The doses of neutrons and gamma rays at these places were measured by thermoluminescence dosimeters four times between June 2019 and May 2020. The radiation doses decreased as the distances from the EAST device shell gradually increased from S1 to S3. The radiation in the EAST hall resulted in a significant induction of MN in the Vicia faba root tip cells compared to a negative control, which was different from the MN frequency induced by fission neutrons, γ-rays and other kinds of radiation in previous studies. These results indicate the existence of potential genotoxic effects induced by radiation from EAST which is different from other radiation and suggest that personnel should not be permitted to enter the experimental hall during the discharge process, and that radiation protection measures should be taken during necessary maintenance to avoid radiation damage. These newly acquired results will certainly increase our knowledge about the biological effects induced by radiation from nuclear fusion and provide good data support for developing more effective environmental and personnel fusion radiation protection.

MULocDeep: A deep-learning framework for protein subcellular and suborganellar localization prediction with residue-level interpretation

Prediction of protein localization plays an important role in understanding protein function and mechanisms. In this paper, we propose a general deep learning-based localization prediction framework, MULocDeep, which can predict multiple localizations of a protein at both subcellular and suborganellar levels. We collected a dataset with 44 suborganellar localization annotations in 10 major subcellular compartments—the most comprehensive suborganelle localization dataset to date. We also experimentally generated an independent dataset of mitochondrial proteins in Arabidopsis thaliana cell cultures, Solanum tuberosum tubers, and Vicia faba roots and made this dataset publicly available. Evaluations using the above datasets show that overall, MULocDeep outperforms other major methods at both subcellular and suborganellar levels. Furthermore, MULocDeep assesses each amino acid’s contribution to localization, which provides insights into the mechanism of protein sorting and localization motifs. A web server can be accessed at http://mu-loc.org.

Cytotoxic and genotoxic evaluation and the toxicological mechanism of uranium in Vicia faba root

This study revealed the cytotoxicity, genotoxicity and toxicity mechanism of uranium (U) in plants. The cytotoxic effect of U was evaluated by detecting the survival status of root border cells; the genotoxic effect was evaluated by micronuclear experiments; and the toxicity mechanism of U to plants was primarily revealed by combining with transcriptome. Results showed that after U exposure, the proportion of late apoptotic cells and dead cells was significantly higher than the control, indicating that U could induce the apoptosis or necrosis of root border cells. The micronucleus rate increased dramatically after U exposure, reaching a maximum of 4.89 times the control, whereas the mitotic index decreased significantly, reaching a minimum of 26.00% of the control. Moreover, the activities of superoxide dismutase and peroxidase decreased, triggering severe oxidative stress. Combined with the transcriptome data, this study showed that U interfered with the expression of genes related to antioxidant enzymes, the cell cycle and the DNA repair system. In conclusion, U strongly terminated the root border cells and blocked the mitosis, therefore inhibiting the growth of the Vicia faba root. It also caused DNA damage by interfering with the antioxidant enzymes to trigger oxidative stress and prevented DNA self-repair by interfering with the DNA repair system.