Background
Arsenic (As) and cadmium (Cd) are two toxic elements that have a relatively high risk of transfer from paddy soil to rice grain. Rice is a major dietary source of these two elements for ...populations consuming rice as a staple food. Reducing their accumulation in rice grain is important for food safety and human health.
Scope
We review recent progress in understanding the biogeochemical processes controlling As and Cd bioavailability in paddy soil, the mechanisms of their uptake, translocation and detoxification in rice plants, and strategies to reduce their accumulation in rice grain. Similarities and differences between the two elements are emphasized. Some knowledge gaps are also identified.
Conclusions
The concentrations of As and Cd in rice grain vary by three orders of magnitude, depending on the bioavailability of the two elements in soil, rice genotype and growing conditions. The redox potential in paddy soil has a profound but opposite effect on As and Cd bioavailability, whereas soil pH affects Cd bioavailability more than As bioavailability. A number of key genes involved in As and Cd uptake, translocation, sequestration, and detoxification in rice have been characterized. Allelic variations of several genes underlying the variations in Cd accumulation have been identified, but more remains to be elucidated, especially for As. Two types of strategies can be used to reduce As and Cd accumulation, reducing their bioavailability in soil or their uptake and translocation in rice. Reducing the accumulation of both As and Cd in rice simultaneously remains a great challenge.
Cadmium (Cd) is highly toxic to most organisms, but some rare plant species can hyperaccumulate Cd in aboveground tissues without suffering from toxicity. The mechanism underlying Cd detoxification ...by hyperaccumulators is interesting but unclear.
Here, the heavy metal ATPase 3 (SpHMA3) gene responsible for Cd detoxification was isolated from the Cd/zinc (Zn) hyperaccumulator Sedum plumbizincicola. RNA interference (RNAi)-mediated silencing and overexpression of SpHMA3 were induced to investigate its physiological functions in S. plumbizincicola and a nonhyperaccumulating ecotype of Sedum alfredii.
Heterologous expression of SpHMA3 in Saccharomyces cerevisiae showed Cd-specific transport activity. SpHMA3 was highly expressed in the shoots and the protein was localized to the tonoplast. The SpHMA3-RNAi lines were hypersensitive to Cd but not to Zn, with the growth of shoots and young leaves being severely inhibited by Cd. Overexpressing SpHMA3 in the nonhyperaccumulating ecotype of S. alfredii greatly increased its tolerance to and accumulation of Cd, but not Zn.
These results indicate that elevated expression of the tonoplast-localized SpHMA3 in the shoots plays an essential role in Cd detoxification, which contributes to the maintenance of the normal growth of young leaves of S. plumbizincicola in Cd-contaminated soils.
Identifying important factors contributing to depression is necessary for interrupting risk pathways to minimize adolescent depression. The study aimed to assess the prevalence of depression in high ...school students and develop a model for identifying risk of depression among adolescents.
Cross-sectional study was conducted. A total of 1190 adolescents from two high schools in eastern China participated in the study. Artificial neurol network (ANN) was used to establish the identification model.
The prevalence of depression was 29.9% among the students. The model showed the top five protective and risk factors including perceived stress, life events, optimism, self-compassion and resilience. ANN model accuracy was 81.06%, with sensitivity 65.3%, specificity 88.4%, and area under the receiver operating characteristic (ROC) curves 0.846 in testing dataset.
The ANN showed the good performance in identifying risk of depression. Promoting the protective factors and reducing the level of risk factors facilitate preventing and relieving depression.
The agronomic application of nanotechnology in plants (phytonanotechnology) has the potential to alter conventional plant production systems, allowing for the controlled release of agrochemicals ...(e.g., fertilizers, pesticides, and herbicides) and target-specific delivery of biomolecules (e.g., nucleotides, proteins, and activators). An improved understanding of the interactions between nanoparticles (NPs) and plant responses, including their uptake, localization, and activity, could revolutionize crop production through increased disease resistance, nutrient utilization, and crop yield. Herewith, we review potential applications of phytonanotechnology and the key processes involved in the delivery of NPs to plants. To ensure both the safe use and social acceptance of phytonanotechnology, the adverse effects, including the risks associated with the transfer of NPs through the food chain, are discussed.
The field of nanotechnology has great potential within plant sciences and plant production systems.
The agronomic application of nanotechnology has thus far received comparatively little interest relative to the application within human systems.
We review the potential applications and future opportunities of nanotechnology in plant sciences, thereby assisting in bridging the divide between human and agricultural nanotechnology.
The application of nanotechnology in plant sciences will benefit from the development of improved analytical techniques that enable the in situ analysis of NPs in planta with a low detection limit and high lateral resolution.
Regardless of the benefits of nanotechnology for plant sciences, the principle of ‘safety-by-design’ must be heeded to address community concerns about the potential adverse effects of novel engineered nanoparticles (ENPs) on ecological systems.
Rapid industrialization in China during the last three decades has resulted in widespread contamination of Cd in agricultural soils. A considerable proportion of the rice grain grown in some areas of ...southern China has Cd concentrations exceeding the Chinese food limit, raising widespread concern regarding food safety. In this review, we summarize rice grain Cd concentrations in national Chinese markets and in field surveys from contaminated areas, and analyze the potential health risk associated with increased dietary Cd intake. For subsistence rice farmers living in some contaminated areas of southern China who mainly consume locally-produced Cd-contaminated rice, their estimated dietary Cd intake is now comparable to that for the population in the region of Japan where the Itai-Itai disease was first reported. Interventions must be taken urgently to reduce Cd intake for these farmers. We also analyze i) the main reasons causing elevated grain Cd concentrations in southern China, ii) the dominant biogeochemical processes controlling the solubility of Cd in paddy soils, and iii) molecular mechanisms for the uptake and translocation of Cd in rice plants. Based on these analyses, we propose a number of countermeasures to address soil Cd contamination, including i) mitigation of Cd transfer from paddy soils to rice grain, and ii) intervention in those farmers who consume home-grown Cd-contaminated rice. Liming to increase soil pH to 6.5 and gene editing biotechnology are effective strategies to decrease Cd accumulation in rice grain. For these local farmers with high-Cd exposure risk, local governments should monitor the Cd concentration in their home-grown rice and exchange those high-Cd rice with low-Cd rice in order to reduce their dietary Cd intake.
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•We review the status of Cd contamination in soils and rice grain in China.•We summarize the biogeochemical processes and molecular tools to produce Cd-safe rice.•We propose a number of countermeasures to tackle soil Cd contamination.•Interventions are required for the local farmers consuming Cd-contaminated rice.
This review analyzes the current status of Cd contamination in agricultural soils and rice grain in China and proposes strategies to tackle this issue, including mitigation and intervention measurements.
Cadmium (Cd) is a toxic and carcinogenic pollutant widely distributed in the environment. Dietary intake is the main source of Cd exposure for the nonsmoking population. Assessment of dietary Cd ...intake provides a pathway to predict Cd body burden and potential health effects. Kidney has been considered as the most sensitive target of chronic Cd exposure. Because of the proportional relationship between Cd accumulation in kidney and Cd excretion via urine, urinary Cd (UCd) has been used as a biomarker of Cd exposure. Here, we review the dietary Cd intake levels in different countries, summarize the global food Cd concentrations reported in both market basket and field surveys, discuss UCd levels among different populations, and illustrate the associations between dietary Cd intake and UCd levels in population-based studies. Recommendations for the prevention and reduction of Cd exposure through anthropogenic inputs and the food chain are also proposed. This review presents a worldwide overview of Cd exposure status through diet for the general population as well as those living in contaminated areas, and provides evidence for policy makers to protect humans from Cd exposure and related health effects.
Rice is a major dietary source of the toxic metalloid arsenic. Reducing arsenic accumulation in rice grain is important for food safety.
We generated transgenic rice overexpressing two aquaporin ...genes, OsNIP1;1 and OsNIP3;3, under the control of a maize ubiquitin promoter or the rice OsLsi1 promoter, and tested the effect on arsenite uptake and translocation.
OsNIP1;1 and OsNIP3;3 were highly permeable to arsenite in Xenopus oocyte assays. Both transporters were localized at the plasma membrane. Knockout of either gene had little effect on arsenite uptake or translocation. Overexpression of OsNIP1;1 or OsNIP3;3 in rice did not affect arsenite uptake but decreased root-to-shoot translocation of arsenite and shoot arsenic concentration markedly. The overexpressed OsNIP1;1 and OsNIP3;3 proteins were localized in all root cells without polarity. Expression of OsNIP1;1 driven by the OsLsi1 promoter produced similar effects. When grown in two arsenic-contaminated paddy soils, overexpressing lines contained significantly lower arsenic concentration in rice grain than the wild-type without compromising plant growth or the accumulation of essential nutrients.
Overexpression of OsNIP1;1 or OsNIP3;3 provides a route for arsenite to leak out of the stele, thus restricting arsenite loading into the xylem. This strategy is effective in reducing arsenic accumulation in rice grain.
Soil contamination with arsenic (As) can cause phytotoxicity and elevated As accumulation in rice grain. Here, we used a forward genetics approach to investigate the mechanism of arsenate (As(V)) ...tolerance and accumulation in rice.
A rice mutant hypersensitive to As(V), but not to As(III), was isolated. Genomic resequencing and complementation tests were used to identify the causal gene. The function of the gene, its expression pattern and subcellular localization were characterized.
OsHAC4 is the causal gene for the As(V)-hypersensitive phenotype. The gene encodes a rhodanase-like protein that shows As(V) reductase activity when expressed in Escherichia coli. OsHAC4 was highly expressed in roots and was induced by As(V). In OsHAC4pro-GUS transgenic plants, the gene was expressed exclusively in the root epidermis and exodermis. OsHAC4-eGFP was localized in the cytoplasm and the nucleus. Mutation in OsHAC4 resulted in decreased As(V) reduction in roots, decreased As(III) efflux to the external medium and markedly increased As accumulation in rice shoots. Overexpression of OsHAC4 increased As (V) tolerance and decreased As accumulation in rice plants.
OsHAC4 is an As(V) reductase that is critical for As(V) detoxification and for the control of As accumulation in rice. As(V) reduction, followed by As(III) efflux, is an important mechanism of As(V) detoxification.
Childhood is a stage of rapid psychological development, movement and psychological development are inseparable. At this stage, games are the main form of activity for children which play a dominant ...role in promoting children's psychological development. By implementing parent-child sports game intervention activities, children can prevent psychological disorders or behavioural problems, help them better adapt to social life, and make more effective contributions to society and humanity. Therefore, current research aimed to check the impact of parent-child sports games on children's psychological development. For this purpose, survey subjects were 50 students from large class of kindergarten A and 50 students from the large class of kindergarten B. An experimental research design was applied by using control and experimental group. The findings that the experimental group showed significant improvements in cognitive ability, emotional stability, willpower, and personality shaping compared to the control group. Moreover, their social adaptability was notably higher, fostering smoother communication and harmonious interpersonal relationships. The findings highlight the importance of early engagement in sports game activities to promote psychological health and resilience in preschool children, emphasizing the need for integrating such activities into early childhood education and parental involvement programs. The research also explored a new research area for further research.
Understanding the paths that influence professional commitment among nursing students is important for helping students continue the nursing profession after graduation. The paths between the ...teaching behaviours of clinical teachers (TBCT) and professional commitment were unknown.
This study aimed to examine whether psychological well-being mediated the relationships between the teaching behaviours of clinical teachers and professional commitment of nursing students. Moreover, we investigated whether the mediating effects of psychological well-being were moderated by optimism.
A cross-sectional design was conducted.
A total of 318 students from 24 hospitals in 13 cities in northern, north-eastern, and eastern China were included in the study.
The instruments used in this study included the scale of teaching behaviours of clinical teachers, a brief inventory of thriving (measuring psychological well-being), a life orientation test (measuring optimism), and a professional commitment scale. The PROCESS macro for SPSS was used to perform mediation analysis and moderated mediation analyses.
Psychological well-being of nursing students partially mediated the relationships between the teaching behaviours of clinical teachers and professional commitment of nursing students. Also, optimism moderated the indirect effect of this mediation model. The indirect effect of clinical teachers' teaching behaviours was stronger for nursing students with low levels of optimism.
The findings suggest that the teaching behaviours of clinical teachers and psychological well-being promote professional commitment. In addition, the mediation of psychological well-being between the teaching behaviours of clinical teachers and professional commitment was conditional on different levels of optimism. Clinical teachers should pay special attention to students with low levels of optimism because teaching behaviours of clinical teachers exert more influence on those students' professional commitment.
•Psychological well-being mediates the relation between teaching behaviours of clinical teachers and professional commitment.•The teaching behaviours of clinical teachers are more strongly related to psychological well-being among students with low optimism.•Teaching behaviours exert more influence on professional commitment of students who have low levels of optimism.
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