[Characterization of AOX family members from Aquilaria sinensis and their responses to wounding].

Aquilaria sinensis is a typical inducible medicinal plant, that can produce agarwood only after it is wounded by external stimuli. Alternative oxidase(AOX) is one of the terminal oxidases of the plant mitochondrial electron transport, which plays an important role in plants' response to environmental stress. In order to reveal the physiological function of AOX gene in the process of agarwood formation from A.sinensis induced by wounding, AOX gene was cloned based on the transcriptome database and then identified by the bioinformatics analysis, and their expression pattern in different tissues and under wounding stress were detected by qRT-PCR. The results as follows. Three AOX genes were cloned from A.sinensis for the first time. They were named AsAOX1a, AsAOX1d and AsAOX2, respectively. The tissue expression shown that AsAOX1a is mainly expressed in the stem and the seed, and the AsAOX1d and AsAOX2 genes are mainly expressed in the pulp and the stem. AsAOX1a and AsAOX1d genes are highly responsive to wounding stress, and their response time was different. In addition, the expression of AsAOX1a and AsAOX2 induced by wounding are reduced by H_2O_2 treatment, but promoted by AsA treatment. The cloning, bioinformatics analysis and expression characteristics of AOX genes from A.sinensis provided basic information for further study the function of AOX genes in the development of A.sinensis, especially in the process of agarwood formation of A. sinensis induced by wounding.

[Effect of arsenic trioxide on differentiation induction of chronic myeloid leukemia k562 cells and its potential mechanism].

OBJECTIVE: This study was to explore the effect of arsenic trioxide (ATO; As(2)O(3)) on differentiation of chronic myeloid leukemia K562 cells and its potential mechanism. METHODS: ATO with different concentration (0.1, 0.5, 1.0, 2.0, 5.0 µmol/L) were used to treat K562 cells, and MTT assay was used to detect the growth level of K562 cells; Benzidine staining was applied to measure the change of hemoglobin content; flow cytometry (FCM) was conducted to detect the expression of CD41 and GPA on K562 cells; RT-PCR and Western blot were used to measure the mRNA expression of BTG1 and TAL1 and the protein expression of BTG1 and TAL1, respectively. RESULTS: ATO significantly inhibited the growth of K562 with dose- and time- dependent manners by benzidine staining, the positive rate of K562 cells induced by ATO reached to 17.63% ± 1.18%, which was significantly higher than that of control (2.87% ± 0.63%) (P < 0.01), and GPA, as the specific marker of erythroid cell differentiation, achieved 68.46% ± 3.67%, while it in control was 3.39% ± 0.84% (P < 0.01), besides, the CD41 expression of megakaryocyte increased but not so obvious as GPA. Meanwhile, the differentiation-related transcriptional factors TAL1 and BTG1 mRNA and the corresponding proteins were expressed more highly. CONCLUSION: ATO can induce the differentiation of K562 cells into erythroid cells and megakaryocyte, which is associated with up-regulation of the related transcription factors TAL1 and BTG1.