Expression profiles of glutathione S-transferase superfamily in Spodoptera litura tolerated to sublethal doses of chlorpyrifos

Chlorpyrifos （CPF） is a broad-spectrum organophosphate insecticide. Glu- tathione S-transferases （GSTs） in insects are a family of detoxification enzymes and they play critical roles in CPF detoxification. Spodoptera litura is one of the most destructive agricultural pests in tropical and subtropical areas in the world. In this study, 37 Slgsts from 46 unique transcripts of gsts in S. litura transcriptome data, including eight pre- viously reported GSTs, were identified and their expression patterns in susceptible and 12-generation-CPF-treated strains were analyzed to understand the roles of these Slgsts in sublethal doses of CPF tolerance. The results indicate that the members of the S. litura GST superfamily could be distinguished into three major groups： one group, includ- ing six cytosolic Slgsts （SIGSTel, SIGSTe3, SIGSTelO, SIGSTe15, SIGSTo2 and SIGSTs5） and two microsomal Slgsts （SIMGSTI-2 and SIMGST1-3）, was directly responsible for CPF induction in both 12-generation-treated and susceptible strains; the second group, including three cytosolic Slgsts （SlGSTe13, SIGSTtl and SIGSTzl） and one microsomal Slgst （SIMGSTI-1）, was induced only in the 12-generation-treated strain; the third group, including eight cytosolic Slgsts （two epsilon, three delta, one omega, one zeta and one un- classified Slgst）, was expressed 1.52-5.15-fold higher in the 12-generation-treated strain than in the susceptible strain.

Bioinspired PcBN/hBN fibrous monolithic ceramic:High-temperature crack resistance responses and self-lubricating performances

The high strength and toughness of natural materials are mainly determined by a combination of mechanisms operating at different length scales,which can be used as a strategy to reduce the intrinsic brittleness of ceramics.Inspired by the architectures of bamboo,the polycrystalline cubic boron nitride/hexagonal boron nitride(PcBN/hBN)fibrous monolithic ceramics with a long fiber arrangement structure was constructed with PcBN fiber cells and hBN cell boundaries,and its crack resistance responses and tribological performances were investigated.The composite ceramic failed in a non-brittle manner with the rising resistance curve(R-curve)behavior,which was attributed to multiscale crack effects in the hierarchical architecture.The maximum crack growth toughness was extremely high(approximately 21 MPa×m^(1/2)),corresponding to a 270%increase over the crack initiation toughness.Excellent fracture resistance could be retained even above 1000℃.Moreover,the composite ceramic exhibited low and stable friction coefficients(approximately 0.33)when paired with a Si_(3)N_(4)pin at high temperature(1000℃),owing to the lubrication function of hBN cell boundaries with weak van der Waals forces and a small amount of liquid B_(2)O_(3)produced.As a result,a synergistic improvement of mechanical and tribological properties at high temperature(1000℃)was realized by combining bionic structure and tribological design.It provides important theoretical and technical support for expanding the application of self-lubricating composite ceramics in harsh environments.