Adaptive changes in pheromone production and release under rearing conditions in stink bugs.

BACKGROUND: Healthy cultures of arthropods are important for pest management programs (e.g. biocontrol). Little is known about how rearing conditions may affect pheromonal interactions. We investigated how rearing histories and densities affect pheromone emission/production in two stink bug species (Hemiptera: Heteroptera), the predatory bug Arma custos, a biocontrol agent, and the bean bug Riptortus pedestris, a pest on legume crops. RESULTS: Nymphs from newly established laboratory colonies of both species produced higher amounts of the defense (dispersal) compound, 4-oxo-(E)-hexenal (OHE), in the presence of conspecific nymphs. Also, when two or more A. custos males were placed together, the dorsal abdominal glands (DAGs) ceased to release aggregation pheromone, whereas the metathoracic glands (MTGs) increased the emission of defensive odors. These changes resulted from exposure to conspecific pheromone odors, as confirmed by exposing bugs to pheromone standards. Hence, pheromone emissions in these stink bugs are readily changed in response to the odors of conspecifics, which may become a problem after long-term rearing. Indeed, an old laboratory colony of A. custos (~30 generations) exhibited less-developed DAGs and reduced pheromone production. Instead, males released significantly more defensive odors from the enlarged MTGs. Furthermore, long-term rearing conditions appeared to favor nymphs that were able to share space with conspecifics by releasing less OHE, which has not yet occurred in the new laboratory colonies. CONCLUSION: Rearing density affects pheromone release in newly established laboratory colonies of stink bug species, whereas long-term rearing results in new pheromonal compositions coinciding with adaptive changes in gland development. © 2023 Society of Chemical Industry.

The synthesis and functionalization of metal organic frameworks and their applications for the selective separation of proteins/peptides.

Recently, proteins separation has drawn great interest for the full investigation of a proteome because the proteins separation is the precondition when conducting clinical research or proteomics research. Metal organic frameworks (MOFs) are fabricated via covalent connection between organic ligands and metal ions/clusters units. MOFs have attracted much attention due to the ultra-high specific surface area, tunable structure, more metal site or unsaturated site, and chemical stability. Over the past decade, different functionalization types of MOFs have been reported in combination with amino acids, nucleic acids, proteins, polymers, and nanoparticles for various applications. In this review, the synthesis and functionalization of MOFs have been thoroughly discussed, and we introduced the existing problems and development trends in these fields. Furthermore, MOFs as advanced adsorbents for selective separation of proteins/peptides are summarized. Additionally, we present a comprehensive prospects and challenges in the preparation of robust functional MOFs-based adsorbents and make a final outlook on their future development prospects in selective separation of proteins/peptides.

Co-pyrolysis of biomass and polyethylene: Insights into characteristics, kinetic and evolution paths of the reaction process.

Investigation on the distribution and mechanism of co-pyrolysis products is vital to the directional control and high-value utilization of agriculture solid wastes. Co-pyrolysis, devolatilization, kinetics characteristics, and evolution paths of corn stalk (CS) and low-density-polyethylene (LDPE) were investigated via thermogravimetric experiments. The co-pyrolysis behaviors could be separated into two stages: firstly, the degradation of CS (150- 400 °C); secondly, the degradation of CS (400- 550 °C). The devolatilization index (DI) increased with the addition of LDPE. Furthermore, a combination of devolatilization chemical analysis with product analysis to analyze the intrinsic mechanism during co-pyrolysis. The results indicated that the yield of alkanes and olefin in gas products increased with the addition of LDPE. Additionally, LDPE pyrolysis maybe abstract hydrogen from CS pyrolysis and evolved into hydrogen, methane, and ethylene. Further, the co-pyrolysis kinetic parameters were computed by using model-free isoconversion methods, which showed promotion of CS pyrolysis and the reduced activation energy. All the activation energy were declined, which indicated a "bidirectional positive effect" during co-pyrolysis. The mean activation energy of P-cellulose (P-CE), P-hemicellulose (P-HM), P-lignin (P-LG), and LDPE decreased by 23.49 %, 12.89 %, 15.36 %, and 27.82 %, respectively. This study further proves the hydrogen donor transfer pathway in the co-pyrolysis process of CS and LDPE, providing theoretical support for the resource utilization of agricultural solid waste.

Facile synthesis of indium hydroxide nanosheet/bismuth molybdate hierarchical microsphere heterojunction with enhanced photocatalytic performance.

Various Bi2MoO6 (BM)-based heterojunctions have been constructed to enhance the photocatalytic performance, but hydroxide/BM heterojunctions were rarely reported. To illustrate function of hydroxides in the heterojunctions for charge separation and photoactivity enhancement, In(OH)3/BM heterojunctions were simply prepared for the first time via in situ growth of In(OH)3 nanosheets on surfaces of BM hierarchical microspheres in a chemical precipitation process at the room temperature. Construction of the heterojunction benefits from formation of In-O-Bi/Mo bonds at the interface between BM and In(OH)3. Photoluminescence spectroscopy, time-resolved fluorescence spectroscopy, and photoelectrochemical tests demonstrate that the In(OH)3/BM heterojunction exhibits considerably accelerated separation of photoinduced charge carriers which results in increased generation rates of reactive oxygen species and enhanced photocatalytic degradation efficiencies for Rhodamine B, salicylic acid, and resorcinol, in comparison with pure BM. The heterojunction shows high chemical stability and satisfactory recyclability. This work provides a new BM-based heterojunction and, more importantly, deep insight into function of hydroxides in the heterojunction, which can direct preparation of other hydroxide-containing heterojunctions.

Space-confined synthesis of monolayer molybdenum disulfide using tetrathiomolybdate intercalated layered double hydroxide as precursor.

Monolayer molybdenum disulfide (M-MoS2) nanosheets (NSs) have attracted tremendous attention owing to their extraordinary properties and extensive potential applications. However, the large-scale and cost-effective fabrication of uniform M-MoS2 NSs remains challenging. Herein, a novel space-confined synthesis strategy was developed for M-MoS2 NSs, using the interlayer spaces of layered double hydroxides (LDHs) as nanoreactors. The 2H-phase M-MoS2 NSs dispersed in water were obtained with a high production yield of ∼98.7%, a quite high monolayer ratio of ∼95%, a homogenous lateral size of ∼89 nm, and a large monodispersed concentration of ∼0.41 g L-1. The so-obtained M-MoS2 exhibits excellent electrocatalytic activity towards the hydrogen evolution reaction compared with bulk MoS2. This work provides an effective route for large-scale fabrication of two-dimensional transition-metal dichalcogenide nanomaterials.