Whole-Genome Sequencing of 117 Chromosome Segment Substitution Lines for Genetic Analyses of Complex Traits in Rice.

Rice is one of the most important food crops in Asia. Genetic analyses of complex traits and molecular breeding studies in rice greatly rely on the construction of various genetic populations. Chromosome segment substitution lines (CSSLs) serve as a powerful genetic population for quantitative trait locus (QTL) mapping in rice. Moreover, CSSLs containing target genomic regions can be used as improved varieties in rice breeding. In this study, we developed a set of CSSLs consisting of 117 lines derived from the recipient 'Huanghuazhan' (HHZ) and the donor 'Basmati Surkb 89-15' (BAS). The 117 lines were extensively genotyped by whole-genome resequencing, and a high-density genotype map was constructed for the CSSL population. The 117 CSSLs covered 99.78% of the BAS genome. Each line contained a single segment, and the average segment length was 6.02 Mb. Using the CSSL population, we investigated three agronomic traits in Shanghai and Hangzhou, China, and a total of 25 QTLs were detected in both environments. Among those QTLs, we found that RFT1 was the causal gene for heading date variance between HHZ and BAS. RFT1 from BAS was found to contain a loss-of-function allele based on yeast two-hybrid assay, and its causal variation was a P to S change in the 94th amino acid of the RFT1 protein. The combination of high-throughput genotyping and marker-assisted selection (MAS) is a highly efficient way to construct CSSLs in rice, and extensively genotyped CSSLs will be a powerful tool for the genetic mapping of agronomic traits and molecular breeding for target QTLs/genes.

[MiR-144 Inhibits the Malignant Biologic Behaviors of Multiple Myeloma Cells by Regulating Wnt4/ß-Catenin Signaling Pathway].

OBJECTIVE: To explore the effect of miR-144 to the biological behavior of multiple myeloma cells and its mechanism. METHODS: RT-PCR was used to detect the expression of miR-144 in multiple myeloma cells and plasma of MM patients. MTT assay was used to detect the proliferation and cloning ability of myeloma cells transfected by miR-144. Flow cytometry was used to detect the cell cycle distribution of myeloma cells with over-expression of miR-144. Apoptosis of myeloma cells with over-expression of miR-144 was detected by TUNEL assay. Transwell cell invasion and migration assay was used to detect the invasion and migration ability of myeloma cells with overexpressing on miR-144.Western blot analysis was used to detect the protein expression levels of MMP-9 and MMP-2 in myeloma cells with over expression of miR-144, as well as the expression levels of proteins related to Wnt/ß-catenin signaling pathway. RESULTS: The expression level of miR-144 in MM cell lines and blood of MM patients was significantly lower than that in control group (P＜0.05). The proliferation, invasion and migration of myeloma cells with over-expression of miR-144 were significantly decreased (P＜0.05), and the apoptosis level was increased (P＜0.05). The expression levels of MMP-9, MMP-2, Wnt/ß-catenin signaling pathway in myeloma cells with over-expression of miR-144 were significantly lower than those in control group (P＜0.05). CONCLUSION: MiR-144 can inhibit the proliferation, migration and invasion of multiple myeloma cells and induce cell apoptosis. The specific mechanism may be related with the activity of inhibiting Wnt/ß-catenin signaling pathway.

Enzymatic activity enhancement of non-covalent modified superoxide dismutase and molecular docking analysis.

The enzyme activity of superoxide dismutase was improved in the pyrogallol autoxidation system by about 27%, after interaction between hydroxypropyl-ß-cyclo-dextrin and superoxide dismutase. Fluorescence spectrometry was used to study the interaction between hydroxypropyl-ß-cyclodextrin and superoxide dismutase at different temperatures. By doing this, it can be found that these interactions increase fluorescence sensitivity. In the meantime, the synchronous fluorescence intensity revealed the interaction sites to be close to the tryptophan (Trp) and tyrosine (Tyr) residues of superoxide dismutase. Furthermore, molecular docking was applied to explore the binding mode between the ligands and the receptor. This suggested that HP-ß-CD interacted with the B ring, G ring and the O ring and revealed that the lysine (Lys) residues enter the nanocavity. It was concluded that the HP-ß-CD caused specific conformational changes in SOD by non-covalent modification.