Aspirin increases metabolism through germline signalling to extend the lifespan of Caenorhabditis elegans.

Aspirin is a prototypic cyclooxygenase inhibitor with a variety of beneficial effects on human health. It prevents age-related diseases and delays the aging process. Previous research has shown that aspirin might act through a dietary restriction-like mechanism to extend lifespan. To explore the mechanism of action of aspirin on aging, we determined the whole-genome expression profile of Caenorhabditis elegans treated with aspirin. Transcriptome analysis revealed the RNA levels of genes involved in metabolism were primarily increased. Reproduction has been reported to be associated with metabolism. We found that aspirin did not extend the lifespan or improve the heat stress resistance of germline mutants of glp-1. Furthermore, Oil Red O staining showed that aspirin treatment decreased lipid deposition and increased expression of lipid hydrolysis and fatty acid ß-oxidation-related genes. The effect of germline ablation on lifespan was mainly mediated by DAF-12 and DAF-16. Next, we performed genetic analysis with a series of worm mutants and found that aspirin did not further extend the lifespans of daf-12 and daf-16 single mutants, glp-1;daf-12 and glp-1;daf-16 double mutants, or glp-1;daf-12;daf-16 triple mutants. The results suggest that aspirin increase metabolism and regulate germline signalling to activate downstream DAF-12 and DAF-16 to extend lifespan.

[Gas Transfer Velocity of CH4 at Extremely Low Wind Speeds].

Thin boundary theory equation (TBL) is widely used to determine gas fluxes across water-air interfaces, and the gas transfer velocity (k600) is the key environmental factor in the equation. A monthly field campaign was carried out during one year to measure CH4 flux and to probe its exchange rate across the air-water interface in a drinking reservoir and 5 adjacent ponds. The ranges of wind speed and surface water temperature were 0-0.75 m·s-1 and 6.3-30.9℃respectively, and their average values were 0.19 m·s-1 and 19.3℃ respectively. The gas transfer velocity of CH4 varied from 0.20 to 1.99 cm·h-1 with an average of 0.50 cm·h-1. Correlation functions between the gas transfer velocity and the wind speed at 10 m height (U10) and surface water temperature (Tw) were given here to quantify k600. There were significant correlations between the fitted values and actual values both for original and bin-averaged data.

[Partial Pressure of Carbon Dioxide and Methane from Autumn to Winter in Xiangxi Bay of the Three Gorges Reservoir].

The Concentrations of dissolved CH4 and CO2 in Xiangxi Bay of the Three Gorges Reservoir from autumn to winter in 2014 were determined with headspace gas chromatography technology. Then their partial pressures of CH4 and CO2 were calculated according to the Henry's law. Their temporal variation and the effects of environmental parameters were also discussed. The results indicated that the CH4 partial pressure in the surface water ranged 0.64-4.43Pa, with an average of (1.69±0.94)Pa. The CO2 partial pressure varied from 49.90 to 868.91Pa, with the average of (328.48±251.63)Pa. The pCO2 and pCH4 had a strong negative correlation (r=-0.618,P<0.01). During the period of monitoring, the pCO2 and pCH4 in surface water were significantly correlated with pH, DO, chlorophyll a, TP, surface water temperature and water level. Compared with pCH4, pCO2 was more closely correlated with various environmental factors.

[Characteristics of Methane Flux Across the Water-air Interface in Subtropical Shallow Ponds].

Five shallow ponds of Yichang were selected to illustrate the characteristics of methane(CH4) in subtropical eutrophic shallow ponds. CH4 flux across the water-air interface was quantified with static floating chamber method for one year. Annual CH4 fluxes of the five ponds were 4.495, 12.702, 6.827, 8.920, 17.560 mg·(m2·h)-1 respectively. Diffusive CH4 fluxes were 0.075, 0.087, 0.118, 0.086, 0.151 mg·(m2·h)-1 respectively and bubble emissions were 4.420, 12.616, 6.709, 8.834, 17.409 mg·(m2·h)-1 respectively. Over 98% of total CH4 flux was bubble emission and CH4 flux was apparently higher than other aquatic ecosystems. So the CH4 flux of shallow waters was high and bubble emission was the dominant way. CH4 emission would be largely underestimated if the research only focus on the diffusion discharge and ignore the bubble emission.