BdorOR88a Modulates the Responsiveness to Methyl Eugenol in Mature Males of Bactrocera dorsalis (Hendel).

Insect attractants are important prevention tools for managing populations of the Oriental fruit fly, Bactrocera dorsalis (Hendel), which is a highly destructive agricultural pest with health implications in tropical and subtropical countries. Methyl eugenol (ME) is still considered the gold standard of B. dorsalis attractants. Mature male flies use their olfactory system to detect ME, but the molecular mechanism underlying their olfactory detection of ME largely remains unclear. Here, we showed that ME activates the odorant receptors OR63a-1 and OR88a in mature B. dorsalis males antennae by RNA-Seq and qRT-PCR analysis. Interestingly, ME only elicited robust responses in the BdorOR88a/BdorOrco-expressing Xenopus oocytes, thus suggesting that BdorOR88a is necessary for ME reception and tropism in B. dorsalis. Next, our indoor behavioral assays demonstrated that BdorOR63a-1 knockdown had no significant effects on ME detection and tropism. By contrast, reducing the BdorOR88a transcript levels led to a significant decrease in the males' responsiveness to ME. Taken together, our results gave novel insight in the understanding of the olfactory background to the Oriental fruit fly's attraction toward ME.

Theoretical study of the adsorption of pentachlorophenol on the pristine and Fe-doped boron nitride nanotubes.

To explore the novel application of boron nitride nanotubes (BNNTs), we investigated the interaction of pentachlorophenol (PCP) pollutant with the pristine and Fe doped (Fe-doped) (8, 0) single-walled BNNTs by performing density functional theory calculations. Compared with the weak physisorption on the pristine BNNT, PCP molecule presents strong chemisorption on the Fe-doped BNNT. The calculated data for the electronic properties indicate that doping Fe atom into the BNNT significantly improves the electronic transport property of BNNT, induces magnetism in the BNNT, and increases its adsorption sensitivity toward PCP molecule. It is suggested that doping BNNTs with Fe is an available strategy for improving the properties of BNNTs, and that Fe-doped BNNT would be a potential resource for adsorbing PCP pollutant in environments.

Theoretical investigation on the chiral diamine-catalyzed epoxidation of cyclic enones: mechanism and effects of cocatalyst.

The asymmetric epoxidation of 2-cyclohexen-1-one with aqueous H(2)O(2) as oxidant, 1,2-diaminocyclohexane as catalyst, and a Brønsted acid trifluoroacetic acid (TFA) as cocatalyst has been studied by performing density functional theory calculations. It is confirmed that the catalyzed epoxidation proceeds via sequential nucleophilic addition and ring-closure processes involving a ketiminium intermediate. Four possible pathways associated with two Z isomers and two E isomers of ketiminium have been explored in detail. Our calculation indicates that these four pathways have high barriers and a small energy gap between two more favorable R and S pathways. We have analyzed the effects of the TFA anion and H(2)O on the activity and enantioselectivity of catalytic epoxidation. It is found that the TFA anion acts as a counterion to stabilize the transition states of the catalytic epoxidation by hydrogen-bond acceptance, leading to decreases in the barriers of the nucleophilic addition and ring-closure processes. The most significant decrease occurred in the ring-closure step of the Z-R-pathway, resulting in H-bond-induced enantioselectivity. Our calculations also show that water cooperates with TFA to further increase the reaction rate significantly.

Mechanism study of the gold-catalyzed cycloisomerization of alpha-aminoallenes: oxidation state of active species and influence of counterion.

A computational study with the B3LYP density functional theory was carried out to study the reaction mechanism for the cycloisomerization of allenes catalyzed by Au(I) and Au(III) complexes. The catalytic performance of Au complexes in different oxidation states as well as the effects of the counterion on the catalytic activities has been studied in detail. Our calculations show that the catalytic reaction is initiated by coordination of the Au(I) or Au(III) catalyst to the distal double bond of allene and activation of allene toward facile nucleophilic attack, then 3-pyrroline obtained via two-step proton shift, followed by demetalation. On the basis of our calculations, H shifts are key steps of the catalytic cycle, which are significantly affected by the gold oxidation state, counterion, ligands, and assistant catalyst. AuCl is found to be more reactive than AuCl(3); however, the Au(III)-catalyzed path does not involve an oxidation state change from Au(III) to Au(I). Our calculated results rationalize the experimental findings well and overthrow the previous conjecture about Au(I) serving as the catalytically active species for Au(III)-catalyzed cycloisomerization.

Mesoscopic simulation study on a weakly charged block polyelectrolyte in aqueous solution.

In this paper, we use density functional theory to study the effect of the charge of solvophilic beads and concentration on the mesoscale structures of polyelectrolyte solution. The polyelectrolyte A6B12A6 was selected as the triblock polymer, and the solvophobic B blocks have no charges, while the solvophilic A blocks are charged. The simulation results showed: at higher concentration (above 50% systems), relatively small charges on the solvophilic block do not alter the bicontinuous phase inherent to uncharged solution, but at moderate concentrations (50% system), even though the charge per solvophilic bead is very small, the order lamellar structures become disturbed. [Figure: see text].