Construction of Tn5 transposon insertion mutants of Ralstonia solanacearum isolated from Pogostemon cablin / 中国中药杂志

Ralstonia solanacearum strain PRS-84 used in this study was isolated from diseased Pogostemon cablin plants in our previous study.The competent cells of R.solanacearum strain PRS-84 were transformed by electroporation with Tn5 transposon and then were plated on TTC agar plates containing kanamycin to select for kanamycin-resistant colonies.The detection of kanamycin-resistant gene in kanamycin-resistant colonies was performed by PCR.Further,the flanking fragments of Tn5 transposon insertion site in the mutants were amplified by inverse PCR,and the flanking fragments were sequenced and analyzed.The results indicated that the kanamycin-resistant colonies were obtained in the transformation experiment of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon.A specific band of approximately 700 bp was amplified by PCR from kanamycin-resistant colonies.The flanking sequences of Tn5 transposon insertion site in the transformants were obtained by inverse PCR.After sequencing and sequence analysis of Tn5 transposon insertion site in mutants,we preliminarily speculated that the Tn5 transposon inserted in the typ A gene,rec O gene and gid A gene in three mutants,respectively.A random mutagenesis system of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon has been established,and the Tn5 insertion mutants have been obtained.This study might facilitate the creation of mutant library and the discovery of the virulence gene of R.solanacearum isolated from P.cablin.

Application of a self-made steel wire guide in the treatment of avulsion fractures of tibial posterior cruciate ligament / 中国骨伤

<p><b>OBJECTIVE</b>To explore the effect of a self-made guiding needle of steel wire in guiding the wire through the tibial tunnel for the treatment of avulsion fractures of tibial posterior cruciate ligament with open reduction and wire fixation.</p><p><b>METHODS</b>From February 2011 to June 2014, a total of 22 patients with avulsion fractures of tibial posterior cruciate ligament underwent surgical treatments were analyzed, including 14 males and 8 females with an average age of 35.6 years old (ranged, 17 to 63 years old). According to Meyers classification, 9 patients were classified as type II, 13 patients were classified as type III. All the patients underwent open reduction and wire fixation with medial knee "L" shape approach. A wire guiding needle was used to guide the wire through the tibial tunnel during operation.</p><p><b>RESULTS</b>With the assistance of wire guidance needles, wires passed through the tibial tunnel rapidly during the operation in all the 22 patients. All the patients were followed up, X-ray imagings 6 months after operation showed the fractures healed well. The average follow-up time in all patients was 6 months (ranged, 6 to 12 months). The averaged Lysholm knee score in 22 knee was 92.7 +/- 3.4. All patients' posterior drawer test were negative.</p><p><b>CONCLUSION</b>Self-made wire guiding needle can simplify the operation procedures in which the wires pass through the tibial tunnel, shorten the operation time, reduce the surgical trauma and complications, and be worthy of clinical application.</p>