Programmed cell death (PCD) plays an important role in insect midgut remodeling during metamorphosis. Insect midgut PCD is triggered by the steroid hormone 20-hydroxyecdysone (20E) and it is mediated by a series of genes. However, the mechanism by which 20E triggers midgut PCD is still unclear. Here, we report a protein phosphatase 6 (PP6) from Helicoverpa armigera playing roles in midgut PCD. PP6 was expressed in the midgut during larval growth and it is significantly increased during metamorphosis. The increase was proven to be regulated by 20E. The juvenile hormone analog methoprene has no effect on PP6 expression. RNA interference analysis suggests that 20E upregulated the PP6 transcript levels through the ecdysone receptor EcRB1. PP6 knockdown by larval feeding or PP6 dsRNA injection resulted in the repression of the midgut PCD during the metamorphic stage. The mechanism was demonstrated to be through the suppression of genes such as Broad (Br), E74a, E75b, HR3, E93, rpr, and caspase, which are involved in 20E signaling pathway or midgut PCD. These findings suggest that PP6 is involved in the 20E signal transduction pathway and participates in the PCD in midgut.

In this paper, the panel data model is built to research the dynamic evolution mechanism of the total factor energy efficiency (TFEE). Then by using the panel data of China from 1991 to 2009, this paper estimates China's TFEE based on the input to the guide DEA model, and empirically researches on the dynamic evolution mechanism of the China's TFEE by comparatively analyzing the contribution rate of every influencing factor to the growth rate of TFEE. The empirical research results show that the TFEE level in China is lower on the whole; only in 2009 the TFEE values achieved its efficiency frontier; there is a panel cointegration in the long run relationship between TFEE and influencing factors. It is clear that both the industrial structure and the structure of energy consumption have negative influence on TFEE, while education level, technical advancement and government influence have positive influence on TFEE. The education level has the greatest contribution to the growth of TFEE. The TFEE will be pushed forward by these influencing factors. The research conclusions of this paper confirm the idea that the increase of energy efficiency depends on the improvement of revelant influencing factors.