Toxicological effects and transcriptome mechanisms of rice (Oryza sativa L.) under stress of quinclorac and polystyrene nanoplastics.

The absorption and accumulation of nanoplastics (NPs) by plants is currently attracting considerable attention. NPs also tend to adsorb surrounding organic pollutants, such as pesticides, which can damage plants. However, molecular mechanisms underlying the phytotoxicity of NPs are not sufficiently researched. Therefore, we analyzed the toxicological effects of 50 mg/L polystyrene NPs (PS 50 nm) and 5 mg/L the herbicide quinolinic (QNC) on rice (Oryza sativa L.) using 7-day hydroponic experiments, explaining the corresponding mechanisms by transcriptome analysis. The main conclusion is that all treatments inhibit rice growth and activate the antioxidant level. Compared with CK, the inhibition rates of PS, QNC, and PS+QNC on rice shoot length were 3.95%, 6.68%, and 11.43%, respectively. The gene ontology (GO) term photosynthesis was significantly enriched by QNC, and the combination PS+QNC significantly enriched the GO terms of amino sugar and nucleotide sugar metabolisms. The chemicals QNC and PS+QNC significantly affected the Kyoto Encyclopedia of Genes and Genomes (KEGG) of the MAPK signaling pathway, plant hormone signal transduction, and plant-pathogen interaction. Our findings provide a new understanding of the phytotoxic mechanisms and environmental impacts of the interactions between NPs and pesticides. It also provides insights into the impact of NPs and pesticides on plants in the agricultural system.

Blood lead and cadmium levels in children: A study conducted in Changchun, Jilin Province, China.

OBJECTIVES: Exposure to lead and cadmium in developing countries is considered to be a public health emergency. The present study was designed to investigate children's exposure to lead and cadmium in Changchun, China. METHODS: A total of 1619 blood samples were collected at random from 1426 children between one and 14 years of age, and 204 adults from Changchun, China. Blood lead and cadmium levels were determined using atomic absorption spectrophotometry. RESULTS: The average blood lead level in children was 60.29 µg/L, with boys exhibiting higher blood lead levels than girls. The average blood cadmium level in children was 1.26 µg/L, and differences were not observed between boys and girls. CONCLUSIONS: Children from Changchun exhibited relatively low blood lead and cadmium levels compared with children from other cities, and higher lead and lower cadmium levels than adults. This may be related to leaded gasoline environmental pollution and children's hand-to-mouth activities.

OBJECTIFS: L'exposition au plomb et au cadmium est considérée comme une urgence de santé publique dans les pays en développement. La présente étude était conçue pour examiner l'exposition des enfants de Changchun, en Chine, au plomb et au cadmium. MÉTHODOLOGIE: Les chercheurs ont colligé au hasard un total de 1 619 prélèvements de sang auprès de 1 426 enfants de un à 14 ans et de 204 adultes de Changchun, en Chine. Ils ont déterminé leur taux de plomb et de cadmium dans le sang au moyen de la spectrophotométrie d'absorption atomique. RÉSULTATS: La plombémie moyenne des enfants s'élevait à 60,29 µg/L et était plus élevée chez les garçons que chez les filles. Le taux moyen de cadmium dans le sang des enfants s'élevait à 1,26 µg/L et n'était pas différent entre les garçons et les filles. CONCLUSIONS: Les enfants de Changchun présentaient un taux relativement faible de plomb et de cadmium dans le sang par rapport aux enfants d'autres villes, et un taux plus élevé de plomb et plus faible de cadmium que les adultes. Ce phénomène peut être lié à la pollution environnementale par l'essence au plomb et au fait que les enfants portent beaucoup leurs mains à leur bouche.

Molecular mechanisms of toxicity and detoxification in rice (Oryza sativa L.) exposed to polystyrene nanoplastics.

Nanoplastics (NPs) are an emerging threat to higher plants in terrestrial ecosystems. However, the molecular of NP-related phytotoxicity remains unclear. In the present study, rice seedlings were exposed to polystyrene (PS, 50 nm) NPs at 0, 50, 100, and 200 mg/L under hydroponic conditions to investigate the induced physiological indices and transcriptional mechanisms. We found that 50, 100, and 200 mg/L PS significantly reduced root (53.05%, 49.61%, and 57.58%, respectively) and shoot (54.63%, 61.56%, and 62.64%, respectively) biomass as compared with the control seedlings. The activities of antioxidant enzymes, including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), were significantly activated in all PS treatment groups, indicating that PS inhibited plant growth and induced oxidative stress. Transcriptome analyses showed that PS modulated the expression of the genes involved in cell detoxification, active oxygen metabolism, mitogen-activated protein kinase (MAPK), and plant hormone transduction pathways. Our study provides new insights into phytotoxicity by demonstrating the potential underlying toxicity of PS NPs in higher plants.

Effects of individual and combined polystyrene nanoplastics and phenanthrene on the enzymology, physiology, and transcriptome parameters of rice (Oryza sativa L.).

Owing to their wide distribution, easy production, and resistance to degradation, microplastics (MPs) represent a globally emerging group of pollutants of concern. Furthermore, their decomposition can result in the generation of nanoplastics (NPs), which cause further environmental issues. Currently, the impact of the combination of these plastics with other organic pollutants on crop growth remains poorly investigated. In this study, a hydroponic experiment was conducted for seven days to evaluate the effects of 50 nm, 50 mg/L polystyrene (PS), and 1 mg/L phenanthrene (Phe) on the growth of rice plants. The results revealed that both Phe and PS inhibited growth and improved the antioxidant potential of rice. Relative to Phe alone, exposure to a combination of PS and Phe reduced Phe accumulation in the roots and shoots by 67.73% and 36.84%, respectively, and decreased the pressure on the antioxidant system. Exposure to Phe alone destroyed the photosynthetic system of rice plant leaves, whereas a combination of PS and Phe alleviated this damage. Gene Ontology (GO) analysis of the rice transcriptomes revealed that detoxification genes and phenylalanine metabolism were suppressed under exposure to Phe, which consequently diminished the antioxidant capacity and polysaccharide synthesis in rice plants. Kyoto Encyclopaedia of Genes and Genomes (KEGG) transcriptome analysis revealed that the combined presence of both PS and Phe improved photosynthesis and energy metabolism and alleviated the toxic effects of Phe by altering the carbon fixation pathway and hormone signal transduction in rice plants. The combination of PS and Phe also prevented Phe-associated damage to rice growth. These findings improve our understanding of the effects of MP/NPs and polycyclic aromatic hydrocarbons on crops.

Effects of polystyrene nanoplastics with different functional groups on rice (Oryza sativa L.) seedlings: Combined transcriptome, enzymology, and physiology.

Plastic particles originate from the daily use of plastics and have become a new form of pollutant. However, the effects of nanoplastics (NPs) on higher plants remain largely unclear, thus requiring further research. In this study, rice plants were exposed to polystyrene (PS) NPs with different functional groups to determine their toxicity. The presence of NPs reduced the biomass and photosynthetic capacity of rice. Compared with control (CK), the heights of rice plants exposed to no-modified PS, carboxyl-modified PS (PS-COOH) and amino-modified PS (PS-NH2) groups decreased by 13.59%, 26.61%, and 42.71%, while the dry shoot weight decreased by 47.46%, 50.09%, and 71.04%, respectively. All treatments activated the antioxidant levels of rice and reduced photosynthesis. Transcriptome analysis showed that NPs induced the expression of genes related to antioxidant enzyme activity in rice roots. Rice could partially reduce the xenobiotic toxicity caused by external sources by regulating phenylpropane biosynthesis and the processes involved in cell detoxification. PS mainly affected the process of RNA metabolism, while PS-COOH mainly affected ion transport, and PS-NH2 mainly affected the synthesis of macromolecular protein, which had different effects on rice growth.