Mixing states and secondary formation processes of organic nitrogen-containing single particles in Guangzhou, China.

Organic nitrogen (ON) compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols, however, the mixing state, secondary formation processes, and influencing factors of ON compounds are still unclear. This paper reports on the mixing state of ON-containing particles based on measurements obtained using a high-performance single particle aerosol mass spectrometer in January 2020 in Guangzhou. The ON-containing particles accounted for 21% of the total detected single particles, and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.

Methyl-CpG binding domain (MBD)2/3 specifically recognizes and binds to the genomic mCpG site with a β-sheet in the MBD to affect embryonic development in Bombyx mori.

Methyl-CpG (mCpG) binding domain (MBD) proteins especially bind with methylated DNA, and are involved in many important biological processes; however, the binding mechanism between insect MBD2/3 and mCpG remains unclear. In this study, we identified 2 isoforms of the MBD2/3 gene in Bombyx mori, MBD2/3-S and MBD2/3-L. Binding analysis of MBD2/3-L, MBD2/3-S, and 7 mutant MBD2/3-L proteins deficient in β1-β6 or α1 in the MBD showed that β2-β3-turns in the β-sheet of the MBD are necessary for the formation of the MBD2/3-mCpG complex; furthermore, other secondary structures, namely, β4-β6 and an α-helix, play a role in stabilizing the β-sheet structure to ensure that the MBD is able to bind mCpG.

Homeobox protein A1-like and DNA methylation regulate embryo-specific Zinc finger protein 615 gene expression and embryonic development in the silkworm Bombyx mori.

DNA methylation and transcription factors play roles in gene expression and animal development. In insects, DNA methylation modifies gene bodies, but how DNA methylation and transcription factors regulate gene expression is unclear. In this study, we investigated the mechanism that regulates the expression of Bombyx mori Zinc finger protein 615 (ZnF 615), which is a downstream gene of DNA methyltransferase 1 (Dnmt1), and its effects on the regulation of embryonic development.

Insights into the different mixing states and formation processes of amine-containing single particles in Guangzhou, China.

The formation processes of particulate amines are closely related to their emission sources and secondary reactions, which can be revealed through the investigation of their real-time mixing states in individual particles. The mixing states of methylamine (MA)-, trimethylamine (TMA)-, and diethylamine (DEA)-containing particles were studied using a high-performance single particle aerosol mass spectrometer (HP-SPAMS) in Guangzhou, China, in January 2020. The sharp increase in TMA particles was found to be closely associated with the increase in the ambient relative humidity (RH), while the MA- and DEA-containing particles were not similarly influenced by the changes in the RH.

The enhanced mixing states of oxalate with metals in single particles in Guangzhou, China.

Recently, internal mixing states of oxalate with metals in single particles have been reported from field studies, yet the role of metals in the formation processes of oxalate remains unclear due to the diversity of chemical components and complex atmospheric environment. In this study, the mixing states of oxalate with five metals, including zinc (Zn), copper (Cu), lead (Pb), vanadium (V) and iron (Fe) were investigated in Guangzhou, China. It was found that 55% of oxalate-containing particles were internally mixed with these metals.