Biomechanical properties of acellular sciatic nerves treated with a modified chemical method

Nerve grafts are able to adapt to surrounding biomechanical environments if the nerve graft itself exhibits appropriate biomechanical properties （load, elastic modulus, etc.）. The present study was designed to determine the differences in biomechanical properties between fresh and chemically acellularized sciatic nerve grafts. Two different chemical methods were used to establish acellular nerve grafts. The nerve was chemically extracted in the Sondell method with a combination of Triton X-100 （nonionic detergent） and sodium deoxycholate （anionic detergent）, and in the modified method with a combination of Triton X-200 （anionic detergent）, sulfobetaine-10 （SB-10, amphoteric detergents）, and sulfobetaine-16 （SB-16, amphoteric detergents）. Following acellularization, hematoxylin-eosin staining and scanning electron microscopy demonstrated that the effect of acellularization via the modified method was similar to the traditional Sondell method. However, effects of demyelination and nerve fiber tube integrity were superior to the traditional Sondell method. Biomechanical testing showed that peripheral nerve graft treated using the chemical method resulted in decreased biomechanical properties （ultimate load, ultimate stress, ultimate strain, and mechanical work to fracture） compared with fresh nerves, but the differences had no statistical significance （P 〉 0.05）. These results demonstrated no significant effect on biomechanical properties of nerves treated using the chemical method. In conclusion, nerve grafts treated via the modified method removed Schwann cells, preserved neural structures, and ensured biomechanical properties of the nerve graft, which could be more appropriate for implantation studies.

Effect of elevated CO2 and O3 on phytohormone-mediated plant resistance to vector insects and insect-borne plant viruses

Climatic variations are becoming important limiting factors for agriculture productivity,as they not only directly affect the plant net primary productivity but can also modulate the outbreak of plant diseases and pests.Elevated CO_2 and O_3 are two important climatic factors that have been widely studied before.Elevated CO_2 or O_3 alters the host plant physiology and affects the vector insects and plant viruses via bottom-up effects of the host plants.Many studies have shown that elevated CO_2 or O_3 decreases the plant nitrogen content,which modulates the characteristics of vector insects.Recent evidence also reveals that hormone-dependent signaling pathways play a critical role in regulating the response of insects and plant viruses to elevated CO_2 or O_3.In the current review,we describe how elevated CO_2 or O_3 affects the vector insects and plant viruses by altering the SA and JA signaling pathways.We also discuss how changes in the feeding behavior of vector insects or the occurrence of plant viruses affects the interactions between vector insects and plant viruses under elevated CO_2 or O_3.We suggest that new insights into the upstream network that regulates hormone signaling and top-down effects of natural enemies would provide a comprehensive understanding of the complex interactions taking place under elevated CO_2 or O_3.