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While the capsid of viruses in the Alphachrysovirus genus is built of subunits of a single coat protein, the capsid of viruses grouped in the Betachrysovirus genus may consist of subunits of two different proteins. For four of these betachrysoviruses, the detected molecular weights of the putative coat proteins differ from the sizes deduced from the nucleic acid sequence. The origin of these modifications remained unclear and it was hypothesized that the coat proteins undergo unspecific degradation. In our study, we show that these modifications are based on processing steps performed by unknown factors present in extracts of several eukaryotic organisms. Furthermore, we show that the C-terminal domain of P3 is fully degraded after capsid processing and particle assembly. • Coat proteins from FgV-ch9 are processed by eukaryotic factors. • The C-terminus of P3 of FgV-ch9 is fully degraded during processing. • Eukaryotic factors are processing P3 of the related betachrysovirus FodV1. [ABSTRACT FROM AUTHOR]

The non-linear relationship between particle sulfate and SO 2 is still unclear. Continuous observations were conducted in a typical city in Northern China from 2017 to 2020. SO 2 concentration continually decreased, however, the SO 4 2− concentration and the sulfur oxidation ratio increased in 2018–2019. The major reason might be the variations of sulfate formation by the aqueous-phase reactions, especially for the O 2 + TMI oxidation (oxygen catalyzed by transition-metal ions). Particle pH, SO 2 , and Mn concentration were the main factors affecting the O 2 + TMI reaction rate. Sensitivity analysis indicated that the decrease of the O 2 + TMI reaction rate caused by SO 2 or Mn concentration dropping by half can only offset the increased rate caused by a 0.1 unit decrease in particle pH. Considering the actual atmospheric environment in Northern China, if the particle pH continues to drop, the slow decline of SO 2 and Mn concentration may not prevent the increase in the O 2 + TMI oxidation rate. In addition to meteorological parameters, the concentrations of SO 4 2−, crustal elements, and total ammonium were the primary factors for the decrease in particle pH in the past 3 years. Therefore, the impact of pH on sulfate formation must be considered when controlling dust and ammonia emissions. [Display omitted] • Changes in O 2 + TMI reaction rates partly explained the non-linear relationship between SO 4 2− and SO 2 ; • If the pH continues to drop, the slow decline of SO 2 and Mn may not offset the increase in the O 2 + TMI oxidation rate. • The concentrations of SO 4 2−, crustal elements and total ammonium were the primary factors for the decrease in particle pH. [ABSTRACT FROM AUTHOR]

Sr-Nd-Pb isotopic tracer was applied, for the first time, to identifying the sources of the particles in the East Rongbuk ice core from Mt. Qomalangma (Everest). The results show that the particles in the dirty layers originate mainly from local sources, while the particles in the non-dirty layers are consistent with the features of dust from the arid regions in northwestern India. The HYSPLIT model shows that the air trajectory goes first through northwestern India before reaching the drilling site of ice core when dust storms occur in northwestern India, confirming northwestern India as a possible source of dust in the East Rongbuk ice core. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

Formaldehyde (HCHO) is one of the most important intermediate products of atmospheric photochemical reactions and is also a radical source that promotes ozone formation. Given its high solubility, HCHO is likely to exist in particulate form. In this work, gaseous HCHO (HCHO g) and particulate HCHO (HCHO p) were separated and collected by a rotating wet annular denude (RWAD) and an aerosol growth chamber–coil aerosol cooler (AC). The collected HCHO from the RWAD and AC are measured by two online Hantzsch method-based formaldehyde analyzers. The comprehensive campaign was held in the Yangtze River Delta of China from 15 May to 18 June 2018, which is during the harvest season. Several biomass burning events were identified by using acetonitrile as a tracer. During the period influenced by biomass burning, the mixing ratios of HCHO g and HCHO p were respectively 122% and 231% higher than those during other time periods. The enhancement ratio of HCHO g to acetonitrile obtained from this work generally agrees with those from the existing literature. Biomass burning contributed 14.8% to HCHO g , but the abundant freshly discharged precursors it emitted greatly promoted the secondary production of HCHO g. We suggest that the high concentration of HCHO p during the biomass burning period was from uptake of HCHO g by aerosols during their transportation; the liquid state particles are conducive to HCHO g uptake. High relative humidity, a low particle rebound fraction f , as well as low temperatures may result in higher uptake coefficient values. Image 1 • Simultaneous online measurements of gaseous HCHO and particulate HCHO were conducted. • Precursors emitted by biomass burning promoted the secondary production of gaseous HCHO. • Particles in liquid state are conducive to uptake HCHO. • High RH and lower temperature may result in higher uptake coefficient. [ABSTRACT FROM AUTHOR]