Insight into the relationship between metabolic enzymes and oxadiazon degradation in Oryza sativa for reducing environmental risks.

Oxadiazon (ODZ) is extensively utilized in agricultural fields for weed control owing to its strong effectiveness. However, excessive loading of ODZ in water bodies and agricultural soils can lead to various environmental concerns. Therefore, it is crucial to understand the ODZ metabolic process and associated mechanisms in crops to assess the likelihood of ODZ contamination in the environment. This study aimed to assess the effects of ODZ on the growth and toxicological responses of rice (Oryza sativa). The growth of rice tissues was notably compromised with the increase in ODZ concentrations. RNA sequencing in combination with liquid chromatography-quadrupole-time-of-flight-high-resolution mass spectrometry/mass spectrometry (LC-Q-TOF-HRMS/MS) analysis allowed for the identification of numerous transcriptional components associated with ODZ metabolism. Four libraries comprising rice roots and shoots exposed to ODZ were RNA-sequenced in triplicate. The application of environmentally realistic ODZ concentrations upregulated the expression of 844 genes in shoots and 1476 genes in roots. Gene enrichment analysis revealed the presence of multiple enzymes involved in ODZ metabolism and detoxification. These enzymes play a critical role in mitigating environmental stress and facilitating xenobiotic metabolism. Notably, among differentially expressed genes, several key enzymes were identified, including cytochrome P450s, protein kinases, aminotransferases, and ATP-binding cassette transporters involved in the metabolic process. Using LC-Q-TOF-HRMS/MS, 3 metabolites and 13 conjugates were identified in multiple metabolic pathways involving oxidation, hydrolysis, glycosylation, acetylation, and methylation. This study successfully established a potential link between the specific metabolic products of ODZ and increased activities of their corresponding enzymes. Moreover, this study considerably elucidates the detailed pathways and mechanisms involved in ODZ metabolism. The study findings provide valuable insights into the development of genotypes for reducing ODZ residues in paddy fields and minimizing their accumulation in rice crops.

[Determination of trace Au in mine sample by inductively coupled plasma atomic emission spectroscopy].

A method for the determination of trace gold by inductively coupled plasma atomic emission spectrometry (ICP-AES) in mine sample was proposed. The instrument parameters were optimized and the media of solution and interferences were studied systemically. The results showed that in less than 10% (phi) aqua regia medium, the acids had no influences on the determination, and after removing common cations in mineral samples by using 10% hydrochloric acid(phi), the residual matrix elements had no effect on the determination of Au with ICP-AES. The silicon in samples had serious spectral interference to Au 208. 2 nm, and the spectral interference was corrected with interference coefficient using the 251.6 nm silicon line. With 10% HCl to remove the matrix and interference correction coefficient to eliminate the interference of silicon, trace gold in high-sulfur tailings samples was determined, the result was identical with the reference values by the method of enrichment with activated carbon-atomic absorption spectrometry. Under the experimental conditions, the detection limit for gold in mine sample was 0.10 g x t(-1).

[Correction of spectral interferences with mutual interference coefficient matrix for determination of impurities in Bi-based superconductor powder by inductively coupled plasma emission spectrometry].

In the present paper a method was proposed for the determination of Fe, Cr, Ni, Si, Al and Ba in Bi-based superconductor powder (BSCCO, Bi(2-x), Pb(x)Sr2Ca2Cu3O8) by inductively coupled plasma atomic emission spectrometry(ICP-AES). The operation parameters for ICP-AES were optimized, and the influences of acid kind and concentration were examined. The interferences of matrix elements Bi, Sr, Pb, Ca and Cu in Bi-based superconductor powder on the determination of impurities were studied systematically. The interference coefficients of Bi, Sr, Pb, Ca and Cu were obtained for each target elements respectively, and the mutual interferences matrix was constituted with the above coefficients. The equated concentrations of background from matrix elements were calculated by interferences coefficients matrix and concentrations of Bi, Sr, Pb, Ca and Cu using Gaussian elimination with full pivoting method. Then the concentrations of impurities were obtained by calculation of differences. By means of the mutual interference coefficients matrix, the artificial sample was determined for the target elements with the recovery coefficient of 99.5%-100.5%. The superconductor powers were analysed with satisfactory results also, and the results were identical with the reference values from ICP-MS.