Roles of Rev-erb alphya and Ror alpha in osteoblastogenesis of mouse bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND: The orphan nuclear receptors Rev-erbα and Rorα play important roles in lipid metabolism and glucose metabolism. But it is unclear whether they are involved in bone metabolism. OBJECTIVE: To observe the expression of Rev-erbα and Rorα during the osteoblastogenesis process of bone marrow mesenchymal stem cells (BMSCs). METHODS: BMSCs were isolated and purified from C57BL/6 mice by the whole bone marrow adherence method followed by morphology observations and then BMSCs were induced to differentiate into osteoblasts and adipocytes. We detected their differentiation abilities using oil red O staining and alizarin red staining, respectively. Real-time PCR and western blot assay were conducted to detect the mRNA and protein levels of Rev-erbα and Rorα in BMSCs cultured in the osteogenic medium for 0, 7, 14 days. RESULTS AND CONCLUSION: BMSCs from C57BL/6 mice were mainly spindle-shaped and exhibited the swirl-like pattern of growth. Following induction, oil red O staining and alizarin red staining produced a positive reaction in these cells. Rev-erbα expression at both gene and protein levels decreased at 0, 7, 14 days after osteogenic induction, while Rorα expression increased at both gene and protein levels. These findings indicate that Rev-erbα and Rorα may participate in the osteoblastogenesis of BMSCs.

Role of stromal cell-derived factor 1/CXC chemokine receptor axis in rat tooth movement / 中国组织工程研究

BACKGROUND:Orthodontic treatment has a long course and referral interval,which is an important difficulty.How to accelerate orthodontic tooth movement is an issue of concern.OBJECTIVE:To testify whether the local injection of AMD3100 (CXCR4 antagonist) can accelerate the tooth movement or not,and to explore the role of stromal cell-derived factor 1/CXC chemokine receptor axis in tooth movement.METHODS:Ninety Sprague-Dawley rats aged 8-10 weeks old were selected and the models of orthodontic tooth movement were established.The model rats were randomized into three groups,and then given the injection of stromal cell-derived factor 1,AMD3100 or PBS.The rats were killed at 1,3,5,7,10 and 14 days to measure the tooth movement distance.RESULTS AND CONCLUSION:The tooth movement distance showed difference among three groups;AMD3100 could facilitate the tooth movement,while stromal cell-derived factor 1 exerted inhibitory effect on the tooth movement.To conclude,stromal cell-derived factor 1/CXC chemokine receptor axis plays an important role in tooth movement.

Genomic variability and molecular evolution of Asian isolates of sugarcane streak mosaic virus.

Sugarcane streak mosaic virus (SCSMV), an economically important causal agent of mosaic disease of sugarcane, is a member of the newly created genus Poacevirus in the family Potyviridae. In this study, we report the molecular characterization of three new SCSMV isolates from China (YN-YZ211 and HN-YZ49) and Myanmar (MYA-Formosa) and their genetic variation and phylogenetic relationship to SCSMV isolates from Asia and the type members of the family Potyviridae. The complete genome of each of the three isolates was determined to be 9781 nucleotides (nt) in size, excluding the 3' poly(A) tail. Phylogenetic analysis of the complete polyprotein amino acid (aa) sequences (3130 aa) revealed that all SCSMV isolates clustered into a phylogroup specific to the genus Poacevirus and formed two distinct clades designated as group I and group II. Isolates YN-YZ211, HN-YZ49 and MYA-Formosa clustered into group I, sharing 96.8-99.5 % and 98.9-99.6 % nt (at the complete genomic level) and aa (at the polyprotein level) identity, respectively, among themselves and 81.2-98.8 % and 94.0-99.6 % nt (at the complete genomic level) and aa (at the polyprotein level) identity, respectively, with the corresponding sequences of seven Asian SCSMV isolates. Population genetic analysis revealed greater between-group (0.190 ± 0.004) than within-group (group I = 0.025 ± 0.001 and group II = 0.071 ± 0.003) evolutionary divergence values, further supporting the results of the phylogenetic analysis. Further analysis indicated that natural selection might have contributed to the evolution of isolates belonging to the two identified SCSMV clades, with infrequent genetic exchanges occurring between them over time. These findings provide a comprehensive analysis of the population genetic structure and driving forces for the evolution of SCSMV with implications for global exchange of sugarcane germplasm.

A One-Step Real-Time RT-PCR Assay for the Detection and Quantitation of Sugarcane Streak Mosaic Virus.

Sugarcane mosaic disease is caused by the Sugarcane streak mosaic virus (SCSMV; genus Poacevirus, family Potyviridae) which is common in some Asian countries. Here, we established a protocol of a one-step real-time quantitative reverse transcription PCR (real-time qRT-PCR) using the TaqMan probe for the detection of SCSMV in sugarcane. Primers and probes were designed within the conserved region of the SCSMV coat protein (CP) gene sequences. Standard single-stranded RNA (ssRNA) generated by PCR-based gene transcripts of recombinant pGEM-CP plasmid in vitro and total RNA extracted from SCSMV-infected sugarcane were used as templates of qRT-PCR. We further performed a sensitivity assay to show that the detection limit of the assay was 100 copies of ssRNA and 2 pg of total RNA with good reproducibility. The values obtained were approximately 100-fold more sensitive than those of the conventional RT-PCR. A higher incidence (68.6%) of SCSMV infection was detected by qRT-PCR than that (48.6%) with conventional RT-PCR in samples showing mosaic symptoms. SCSMV-free samples were verified by infection with Sugarcane mosaic virus (SCMV) or Sorghum mosaic virus (SrMV) or a combination of both. The developed qRT-PCR assay may become an alternative molecular tool for an economical, rapid, and efficient detection and quantification of SCSMV.