Metabolic engineering of (E)-β-farnesene synthase genes for aphid-resistant genetically modified plants / 生物工程学报

Aphids are major agricultural pests that cause significant yield losses of crops each year. (E)-β-farnesene (EβF), as the main component of the aphid alarm pheromones, can interrupt aphid feeding and cause other conspecies in the vicinity to become agitated or disperse from their host plant. Furthermore, EβF can function as a kairomone in attracting aphid predators. EβF synthase genes, which encode enzymes that convert farnesyl diphosphate (FPP) to the acyclic sesquiterpene EβF, have been isolated and characterized from peppermint (Mentha × piperita and Mentha asiatica), Yuzu (Citrus junos), Douglas fir (Pseudotsuga menziesii), sweet wormwood (Artemisia annua) and chamomile (Matricaria recutita), respectively. Transgenic plant overexpressing EβF synthase genes has been one of the most efficient strategies for aphid management. In this review, the current statuses of transgenic plants engineered for aphid resistance were summarized. The plant-derived EβF synthase genes with their potential roles in aphid management via genetic-modified (GM) approaches were reviewed. The existing problem in GM plants with EβF synthase gene, such as low EβF emission was usually detected in the transgenic plant, was discussed and the development direction in this area was proposed.

Effects of three types of fusion methods on stress of adjacent segments by finite element analysis / 实用医学杂志

Objective To study the different biomechanics surgical effects of posterolateral fusion , the transverse fusion and the interbody fusion. Method Scan CT was followed with preprocess of images. The Mimics , HyperMesh and Geomagic Studio Reverse engineering softwares were used to establish the modles of lumbar fusion , then the finite element computation was conducted by using the Abaqus finite element software. Result The EF of each lumbar modle was established , the EF of the interbody fusionwas rised evidently. After the fusion , the stress of the adjacent lumbar were also rised, among them the stress of the upper adjacent segment in tnterbody fusion was the most in extension and rotation , with statistical significance ( P 0.05). About the under adjacent sengment, in the extension and antexion, the stress of the interbody fusion was the most, and the new type of posterolateral fusion was the least, the three of them all haved statistical significance (P0.05). Conclusion After the fusion, the EF of the lumbar and the stress of the lumbar disc are all established, the interbody fusion is most, while the others are lower.