Identification of Reliable Reference Genes under Different Stresses and in Different Tissues of Toxicodendron succedaneum.

Toxicodendron succedaneum (L.) Kuntze (T. succedaneum) is an economic tree species that produces urushiol and urushi wax, and it is of great value in industry and medicine. However, the stability of reference genes (RGs) has not been systematically reported in T. succedaneum to date. In this study, the expression of 10 candidate RGs was analyzed by RT-qPCR in different tissues (roots, stems, leaves), stress treatments (high/low temperature, drought), and hormone stimulation (jasmonic acid, JA). Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper. Finally, RefFinder was used to comprehensively analyze the expression stability of 10 candidate genes. The comprehensive analysis showed that TsRG05/06, TsRG01/06, and TsRG03/ACT were stable under high/low-temperature stress, drought stress, and JA treatment, respectively. TsRG03 and ACT had stable expression in different tissues. While the TsRG03 and ACT were recommended as the suitable RGs for T. succedaneum in all samples. Meanwhile, UBQ was the least suitable as a reference gene for T. succedaneum. In addition, the results of geNorm showed that the combination of two stable RGs could make the results of gene expression more accurate. These results provide alternative RGs for the study of gene function, correction, and normalization of target gene expression and directed molecular breeding in T. succedaneum.

Multiplexed electrochemical aptasensor based on mixed valence Ce(III, IV)-MOF for simultaneous determination of malathion and chlorpyrifos.

In this work, a multiplexed electrochemical aptasensor based on mixed valence Ce-MOF was constructed for the simultaneous determination of malathion and chlorpyrifos. Firstly, Ce(III, IV)-MOF materials with many catalytic sites were synthesized and characterized by SEM, TEM, XPS, FT-IR, XRD, and UV-Vis. Then, the chlorpyrifos and malathion signal markers based on Ce(III, IV)-MOF were prepared using thionine (Thi) and ferrocene (Fc) used as the electrochemical probe. The electrochemical signal was amplified by the reduction of thionine catalyzed by the spontaneous cycle of Ce(III, IV) in Ce(III, IV)-MOF skeleton and the reduction of ferrocene catalyzed by ascorbic acid (AA) in solution. The detection of the two targets did not interfere with each other, and the quantitative detection was realized with high sensitivity. The detection range of chlorpyrifos and malathion were 1.0 µM ∼ 0.1 pM, and the detection limits of chlorpyrifos and malathion were 0.038 and 0.045 pM (S/N = 3), respectively. The sensor provided a new idea for the simultaneous determination of multi-component and had a high application prospect in the field of food safety in the future.

PyunBBX18 Is Involved in the Regulation of Anthocyanins Biosynthesis under UV-B Stress.

(1) Background: Populus yunnanensis Dode (P. yunnanensis) grows in the low-latitude and high-altitude areas of southwest China. In low-latitude and high-altitude areas, plants suffer from the high intensity of UV-B (ultraviolet-b) radiation, and they have a complete regulation system to adapt to the environment of the high UV-B radiation. As natural antioxidants, anthocyanins play an important role in scavenging free radicals. BBX (B-box) genes are involved in anthocyanins biosynthesis. (2) Methods: By exploring the gene structure and motifs of PyunBBX genes (genes of P. yunnanensis BBX family) and the evolutionary relationship between PyunBBX genes and other species BBX genes, six PyunBBX genes that responded to UV-B and participated in anthocyanins biosynthesis were screened. BBX, with the potential to regulate anthocyanins biosynthesis, was further investigated by anthocyanins content determination and RT-qPCR (real-time quantitative polymerase chain reaction); (3) Results: After 7 days of UV-B treatment, anthocyanins were significantly accumulated, and the expression of PyunBBX18 was up-regulated for 7 days. The expression of PyunBBX12 was inhibited by UV-B treatment. By analyzing the RNA-seq data of leaves and bark of P. yunnanensis, we found that PyunBBX18 was highly expressed in leaves and young bark; (4) Conclusions: These results showed that PyunBBX18 and PyunBBX12 may be involved in the response process of UV-B stress, in which PyunBBX18 may regulate the anthocyanins biosynthesis to resist UV damage.

LC-MS3 Strategy for Quantification of Carbamazepine in Human Plasma and Its Application in Therapeutic Drug Monitoring.

This study developed a detection method based on the strategy of HPLC/MS3 and verified its suitability by quantifying carbamazepine in human plasma. The high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS3) system was performed using a Shimadzu UFLC XR liquid chromatography and a SCIEX QTRAP® 5500 linear ion trap triple quadrupole mass spectrometer. The specific operation was as follows: the sample protein was firstly precipitated using methanol, then carbamazepine and carbamazepine-D2N15 were separated on an ACQUITY UPLC HSS T3 column using the gradient elution with solvent A (0.1% formic acid) and solvent B (0.1% formic acid in acetonitrile) at a flow rate of 0.25 mL/min. Each sample was run for 7 min. This method was validated for various parameters including accuracy, precision, selectivity, linearity, LLOQ, etc. Only 5 µL of sample plasma could obtain the result of LLOD 0.5 µg/mL. The intra-day and inter-day precision was <8.23%, and accuracy was between -1.74% and 2.92%. This method was successfully used for monitoring the blood concentration of epilepsy patients after carbamazepine treatment.