Tolerances of Apple Maggot (Diptera: Tephritidae) Larvae and Different Age Puparia to Water Flotation and Immersion

Tolerance of terrestrial insects in temperate regions to water immersion and hypoxia has rarely been studied but can be an important adaptation to moist environments, with implications for insect dispersal through waterways. In the Pacific Northwest of the United States, apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), can be found in riparian habitats subject to flooding. Here, survival of R. pomonella larvae and different age puparia after flotation or immersion in 13.3°C or 21.1°C water for 1–12 d was determined. Larvae sank in water and when submerged for 1 or 2 d suffered greater mortality than control larvae. Fewer young (1–2 d old) than older puparia (13–15 d old) floated in water. When immersed in water for 1–12 d, young puparia suffered greater mortality than older puparia, which were not affected by water immersion. Consequently, fewer adult flies eclosed from puparia that had been water treated when young than older. Adult flies from pre-chill and post-chill puparia that had been water treated eclosed later than control flies, but treatment flies survived about 60 d and reproduced. Although newly-formed puparia are susceptible to hypoxic water conditions, increased buoyancy and water tolerance occur rapidly after formation, perhaps making survival possible and allowing water-borne dispersal of older puparia.

Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Trichloroethylene (TCE) removal was investigated in a post-plasma catalysis (PPC) configuration in nearly dry air (RH = 0.7%) and moist air (RH = 15%), using, for non-thermal plasma (NTP), a 10-pin-to-plate negative DC corona discharge and, for PPC, Ce0.01Mn as a catalyst, calcined at 400 °C (Ce0.01Mn-400) or treated with nitric acid (Ce0.01Mn-AT). One of the key points was to take advantage of the ozone emitted from NTP as a potential source of active oxygen species for further oxidation, at a very low temperature (100 °C), of untreated TCE and of potential gaseous hazardous by-products from the NTP. The plasma-assisted Ce0.01Mn-AT catalyst presented the best CO2 yield in dry air, with minimization of the formation of gaseous chlorinated by-products. This result was attributed to the high level of oxygen vacancies with a higher amount of Mn3+, improved specific surface area and strong surface acidity. These features also allow the promotion of ozone decomposition efficiency. Both catalysts exhibited good stability towards chlorine. Ce0.01Mn-AT tested in moist air (RH = 15%) showed good stability as a function of time, indicating good water tolerance also.

Stable Performance of Supported PdOx Catalyst on Mesoporous Silica-Alumina of Water Tolerance for Methane Combustion under Wet Conditions

In methane combustion, water tolerance of Pd-based catalysts is quite critical for stable performance, because water is produced in situ and a water-containing feed is used under real conditions. Herein, water-tolerant mesoporous silica-alumina (H-MSA) was prepared by solvent deficient precipitation (SDP) using triethoxy(octyl)silane (TEOOS) and aluminum isopropoxide (AIP). The H-MSA was more tolerant to water than γ-alumina, mesoporous alumina (MA), and mesoporous silica-alumina (MSA) synthesized by using tetraethyl orthosilicate (TEOS), because of the silica present on the external particle surface. Moreover, it exhibited better textural properties, leading to higher dispersion of PdOx. The PdOx catalyst supported on H-MSA was quite durable in repeated temperature-programmed cycles and isothermal tests in the presence of water vapor, compared to the reference PdOx catalysts. The measured stability was attributed to the water tolerance, weak Lewis acidity, and penta-coordinated Al species of the H-MSA support, which was preferentially imparted when TEOOS was added for substitution of 5 mol% AIP for the synthesis of H-MSA. Therefore, the SDP method employed herein is useful in endowing supported PdOx catalysts with the water tolerance necessary for stable methane combustion performance under wet conditions.

Changing microbial activities during low salinity acclimation in the brown alga Ectocarpus subulatus

SummaryEctocarpus subulatus is one of the few brown algae found in river habitats. Its ability to tolerate freshwater is due, in part, to its uncultivated microbiome. We investigated this phenomenon by modifying the microbiome of laboratory-grown E. subulatus using mild antibiotic treatments, which affected its ability to grow in low salinity. The acclimation to low salinity of fresh water-tolerant and intolerant holobionts was then compared. Salinity had a significant impact on bacterial gene expression as well as the expression of algae- and bacteria-associated viruses in all holobionts, albeit in different ways for each holobiont. On the other hand, gene expression of the algal host and metabolite profiles were affected almost exclusively in the fresh water intolerant holobiont. We found no evidence of bacterial protein production that would directly improve algal stress tolerance. However, we identified vitamin K synthesis as one possible bacterial service missing specifically in the fresh water-intolerant holobiont in low salinity.We also noticed an increase in bacterial transcriptomic activity and the induction of microbial genes involved in the biosynthesis of the autoinducer AI-1, a compound that regulates quorum sensing. This could have caused a shift in bacterial behavior in the intolerant holobiont, resulting in virulence or dysbiosis.Originality-Significance StatementThe importance of symbiotic microbes for the health and stress resistance of multicellular eukaryotes is widely acknowledged, but understanding the mechanisms underlying these interactions is challenging. They are especially difficult to separate in systems with one or more uncultivable components. We bridge the gap between fully controlled, cultivable model systems and purely environmental studies through the use of a multi-omics approach and metabolic models on experimentally modified “holobiont” systems. This allows us to generate two promising working hypotheses on the mechanisms by which uncultivated bacteria influence their brown algal host’s fresh water tolerance.

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption

A porous molecular crystal (PMC) assembled by close-packing of macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for selective CO₂ capture. The 7.1´7.1 Å square pore of PMC and its ester C=O group play important roles in improving its affinity for CO₂ molecules. Thermodynamically, the benzene walls of macrocycle strongly promote CO₂ adsorption via [p···p] interactions at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0´5.0 Å square, which offers kinetic selectivity for CO₂ capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. In mixed-gas breakthrough experiments, it exhibits efficient CO₂/N₂ and CO₂/CH₄ separations under kinetic flow conditions. Most importantly, the moderate adsorbate–adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption (PSA) processes. The eluted N₂ and CH₄ are obtained with over 99.9% and 99.8% purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, these properties make cyclotetrabenzoin acetate a promising adsorbent for CO₂ separations from flue and natural gases.

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption

A porous molecular crystal (PMC) assembled by close-packing of macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for selective CO₂ capture. The 7.1´7.1 Å square pore of PMC and its ester C=O group play important roles in improving its affinity for CO₂ molecules. Thermodynamically, the benzene walls of macrocycle strongly promote CO₂ adsorption via [p···p] interactions at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0´5.0 Å square, which offers kinetic selectivity for CO₂ capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. In mixed-gas breakthrough experiments, it exhibits efficient CO₂/N₂ and CO₂/CH₄ separations under kinetic flow conditions. Most importantly, the moderate adsorbate–adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption (PSA) processes. The eluted N₂ and CH₄ are obtained with over 99.9% and 99.8% purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, these properties make cyclotetrabenzoin acetate a promising adsorbent for CO₂ separations from flue and natural gases.