Chinese Wheat Mosaic Virus-Induced Gene Silencing in Monocots and Dicots at Low Temperature.

Virus-induced gene silencing (VIGS) is an important tool for functional genomics studies in plants. With this method, it is possible to target most endogenous genes and downregulate the messenger RNA (mRNA) in a sequence-specific manner. Chinese wheat mosaic virus (CWMV) has a bipartite, single-strand positive RNA genome, and can infect both wheat and Nicotiana benthamiana, and the optimal temperature for systemic infection in plants is 17°C. To assess the potential of the virus as a vector for gene silencing at low temperature, a fragment of the N. benthamiana or wheat phytoene desaturase (PDS) gene was expressed from a modified CWMV RNA2 clone and the resulting photo bleaching in infected plants was used as a reporter for silencing. Downregulation of PDS mRNA was also measured by quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR). In experiments using fragments of PDS ranging from 500 to 1500 nucleotides, insert length influenced the stability and the efficiency of VIGS. The CWMV induced silencing system was also used to suppress miR165/166 and miR3134a through expression of miRNA target mimics. The relative expression levels of mature miR165/166 and miR3134a decreased whereas the transcript levels of their target genes increased. Interestingly, we also found the CWMV-induced silencing system was more efficient compare with the vector based on Barley stripe mosaic virus (BSMV) or Foxtail mosaic virus (FoMV) in wheat or the vector based on TRV in N. benthamiana at 17°C. In summary, the CWMV vector is effective in silencing endogenous genes and miRNAs at 17°C, thereby providing a powerful tool for gene function analysis in both N. benthamiana and wheat at low temperature.

[Influence of Co-inhibiting mTORC2 and HSP90 on Proliferation Apoptosis of Multiple Myeloma Cells].

UNLABELLED: Objective：To explore the influence of co-inhibiting mTORC2 and HSP90 on the proliferation and apoptosis of multiple myeloma(MM) cell line U266. METHODS: During culture, the human MM cell line U266 were treated with 20 nmol/L of rapamycin, 600 nmol/L 17-AAG, 20 nmol/L of rapamycin + 600 nmol/L 17-AGG and phosphate-buffered saline (PBS), then the growth inhibition rate, morphologic changes, apoptosis rate and the expression of caspase 3 and ATK protein in U266 cells were compared and analyzed. RESULTS: The rapamycin and 17-AAG both could inhibit the growth of U266 cells, while the inhibitory effect of rapamycin in combination with 17-AAG on growth of U266 cells was significantly higher them that of rapamycin and 17-AAG alone and control (PBS); the apoptosis rate of U266 cells treated with rapamycin, 17-AAG and their combination was higher than that of control PBS groups, and the efficacy of 2 drug conbination was higher than that of control PBS group, and the efficacy of 2 drug combination was superior to single drug. The expression levels of caspase 3 and ATK in U266 cells treated with rapamycin, 17-AAG and their combination were higher and lower than those in control group respectively, and the efficacy of 2 drug combination was superior to signle drug. There were significant difference between them (P<0.05). CONCLUSION: The co-inhibition of mTORC2 and HSP90 can suppress the proliferation and induce the apoptosis of MM cells.

[The microbiology and antimicrobial susceptibility of the infected knee arthroplasty].

OBJECTIVES: To describe the microbiology, antimicrobial susceptibility of patients proven prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA)and to provide reference for the diagnosis and treatment of this complication. METHODS: The medical data of the patients with infected knee arthroplasty, who were managed with revision surgery between January 1995 to December 2011 were reviewed. Twenty-nine cases were identified and majority of the patients were female (23/29). Diagnosis of PJI after primary TKA was between 1 week and 10 years (average 24.3 months). The microbiology and antimicrobial susceptibility were analyzed. RESULT: The overall positive rate of cultures was 65.5% (19/29). The most common organisms identified were Coagulase-negative Staphylococcus (CNS) (7/19) and Staphylococcus Aureus (SA) (5/19). Rare pathogens of Mycobacterium (2/19) and fungi (1/19) were also identified. Vancomycin was the most effective antibiotics with overall sensitivity rates of 100%.Resistant and rare pathogens were all in type IV infection. CONCLUSIONS: Gram-positive bacterias are the main pathogen, resistant and rare pathogens should be payed attention to. Antibiotic treatment for infected TKA should be based on the results of drug susceptibility. Vancomycin allows infected knee arthroplasties before the result.