Transformation-mediated mutagenesis in both targeted and random manners has been widely applied to decipher gene function in diverse fungi. However, a transformation system has not yet been established for lichen fungi, severely limiting our ability to study their biology and mechanism underpinning symbiosis via gene manipulation. Here, we report the first successful transformation of the lichen fungus, Umbilicaria muehlenbergii, via the use of Agrobacterium tumefaciens. We generated a total of 918 transformants employing a binary vector that carries the hygromycin B phosphotransferase gene as a selection marker and the enhanced green fluorescent protein gene for labeling transformants. Randomly selected transformants appeared mitotically stable, based on their maintenance of hygromycin B resistance after five generations of growth without selection. Genomic Southern blot showed that 88% of 784 transformants contained a single T-DNA insert in their genome. A number of putative mutants affected in colony color, size, and/or morphology were found among these transformants, supporting the utility of Agrobacterium tumefaciens-mediated transformation (ATMT) for random insertional mutagenesis of U. muehlenbergii. This ATMT approach potentially offers a systematic gene functional study with genome sequences of U. muehlenbergii that is currently underway.
Background
The aim of this study is to evaluate the postoperative stability of zygomaticomaxillary complex (ZMC) fractures according to the number of fixation sites and to investigate the direction of postoperative displacement of the unfixed part of the fractured segment.
Methods
This study was retrospectively performed on 38 patients who were treated by open reduction and internal fixation of ZMC fractures and were taken postoperative computed tomography (CT) between February 2012 and July 2019. The patients were classified into 3 groups: 1-point fixation, 2-point fixation, 3-point fixation according to the number of fixations. The postoperative displacement of the fractured segment was evaluated by the superimposition between postoperative CT and follow-up CT, and the postoperative stability according to the fixation sites was investigated through the amount of postoperative displacement. In addition, it was investigated in which direction the location of the fractured segment was changed in the unfixed fractured segment according to the fixation sites.
Results
The amount of postoperative displacement of the fractured segment was 0.75 ± 1.18 mm on average.
In the postoperative displacement of the distal area according to the number of fixation of the fracture, there was no statistically significant difference in the amount of displacement of the fracture (p = 0.574).
As for the direction of the change in the location of the fractured segment, 12 patients among 38 patients with the change in the location of the fractured segment were investigated, and the displacement in the medial direction (n = 11, 91.67%) was the most common in all three fixation methods.
Conclusion
In patients with a ZMC fracture who were treated by open reduction and internal fixation, the number of fixations did not make the difference in the postoperative displacement of the fracture. In addition, the fractured segment mainly changes in the medial direction after surgery, and this fact can be used as a reference for the reduction direction during surgery for the stable prognosis.
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