Identification and Expression Profiles of Putative Soluble Chemoreception Proteins from Lasioderma serricorne (Coleoptera: Anobiidae) Antennal Transcriptome.

The cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae), is a destructive stored product pest worldwide. Adult cigarette beetles are known to rely on host volatiles and pheromones to locate suitable habitats for oviposition and mating, respectively. However, little is known about the chemosensory mechanisms of these pests. Soluble chemoreception proteins are believed to initiate olfactory signal transduction in insects, which play important roles in host searching and mating behaviors. In this study, we sequenced the antennal transcriptome of L. serricorne and identified 14 odorant-binding proteins (OBPs), 5 chemosensory proteins (CSPs), and 2 Niemann-Pick C2 proteins (NPC2). Quantitative realtime PCR (qPCR) results revealed that several genes (LserOBP2, 3, 6, and 14) were predominantly expressed in females, which might be involved in specific functions in this gender. The five LserOBPs (LserOBP1, 4, 8, 10, and 12) that were highly expressed in the male antennae might encode proteins involved in specific functions in males. These findings will contribute to a better understanding of the olfactory system in this stored product pest and will assist in the development of efficient and environmentally friendly strategies for controlling L. serricorne.

Effects of mulching duration on PAEs accumulation in soil and tobacco leaves in Zunyi, China.

We examined the effects of the duration of plastic film mulching on the accumulation of phthalate (PAEs) in soils and tobacco to determine the soil pollution distribution characteristics of PAEs under continuous mulch use and the enrichment status in tobacco leaves. Samples of both soils and tobacco leaves were collected from Lianqian Village and Shawan Village of Zunyi. Gas chromatography-mass spectrometry (GC-MS) was used to determine the contents of six preferentially controlled PAEs in samples. The results showed that the six ΣPAEs in all soil and tobacco samples were (2.66 ±0.60) and (3.58±0.64) mg·kg-1, of which the content of DEHP was the highest, followed by DBP, with the sum of those two accounting for 92.7% and 88.9% of ∑PAEs in the soil and tobacco, respectively. The detection rates of DEHP, DBP, DEP, and BBP were 100.0%. The detection rate of DMP was slightly lower, and that of DnOP was the lowest. The content of PAEs in soils and tobacco leaves significantly increased with the increases of mulching years. In the 1-8 years of film mulching, the increases of PAEs were more obvious and tended to be gentle in the later stage. The content of PAEs in soil and tobacco leaves had significant positive correlation with the years of film mulching, indicating that the increase of film mulching years could significantly promote the accumulation of PAEs. There was no significant correlation between the ∑PAEs accumulation between tobacco leaves and soil.

Polyacrylic acid-coated cerium oxide nanoparticles: An oxidase mimic applied for colorimetric assay to organophosphorus pesticides.

It is important and urgent to develop reliable and highly sensitive methods that can provide on-site and rapid detection of extensively used organophosphorus pesticides (OPs) for their neurotoxicity. In this study, we developed a novel colorimetric assay for the detection of OPs based on polyacrylic acid-coated cerium oxide nanoparticles (PAA-CeO2) as an oxidase mimic and OPs as inhibitors to suppress the activity of acetylcholinesterase (AChE). Firstly, highly dispersed PAA-CeO2 was prepared in aqueous solution, which could catalyze the oxidation of TMB to produce a color reaction from colorless to blue. And the enzyme of AChE was used to catalyze the substrate of acetylthiocholine (ATCh) to produce thiocholine (TCh). As a thiol-containing compound with reducibility, TCh can decrease the oxidation of TMB catalyzed by PAA-CeO2. Upon incubated with OPs, the enzymatic activity of AChE was inhibited to produce less TCh, resulting in more TMB catalytically oxidized by PAA-CeO2 to show an increasing blue color. The two representative OPs, dichlorvos and methyl-paraoxon, were tested using our proposed assay. The novel assay showed notable color change in a concentration-dependent manner, and as low as 8.62 ppb dichlorvos and 26.73 ppb methyl-paraoxon can be readily detected. Therefore, taking advantage of such oxidase-like activity of PAA-CeO2, our proposed colorimetric assay can potentially be a screening tool for the precise and rapid evaluation of the neurotoxicity of a wealth of OPs.