Drought effects on volatile organic compound emissions from Scots pine stems

Systematic Description of the Content Variation of Natural Products (NPs): To Prompt the Yield of High-Value NPs and the Discovery of New Therapeutics

Natural products (NPs) have long been associated with human production and play a key role in the survival of species. Significant variations in NP content may severely affect the "return on investment" of NP-based industries and render ecological systems vulnerable. Thus, it is crucial to construct a platform that relates variations in NP content to their corresponding mechanisms. In this study, a publicly accessible online platform, NPcVar (http://npcvar.idrblab.net/), was developed, which systematically described the variations of NP contents and their corresponding mechanisms. The platform comprises 2201 NPs and 694 biological resources, including plants, bacteria, and fungi, curated using 126 diverse factors with 26,425 records. Each record contains information about the species, NP, and factors involved, as well as NP content data, parts of the plant that produce NPs, the location of the experiment, and reference information. All factors were manually curated and categorized into 42 classes which belong to four mechanisms (molecular regulation, species factor, environmental condition, and combined factor). Additionally, the cross-links of species and NP to well-established databases and the visualization of NP content under various experimental conditions were provided. In conclusion, NPcVar is a valuable resource for understanding the relationship between species, factors, and NP contents and is anticipated to serve as a promising tool for improving the yield of high-value NPs and facilitating the development of new therapeutics.

Spatial and temporal analysis of HCHO response to drought in South Korea

Though drought is known to affect biogenic emissions of volatile organic compounds (BVOC), its effect on isoprene and formaldehyde (HCHO), a high yield product of isoprene, has not been investigated in East Asia where incidences of drought have increased in recent years. In this work, we analyzed the impact of drought on HCHO in the South Korea region during the summer period (June, July, and August) from 2005 to 2018 and found increased HCHO due to drought. The tropospheric HCHO column density retrieved by OMI increased by 8.02 % during extreme drought compared to the non-drought period, whereas no significant effect of drought on the NO₂ column was found. Regional variation of HCHO response to drought correlates significantly with the tree percentage of the region. This correlation indicates that the drought-led HCHO increases are most likely driven by the increase in isoprene emissions during drought. Indeed, model predicts isoprene emissions to be higher by 27.87 % during the extreme drought compared to the non-drought period in South Korea. From 2005 to 2018, the HCHO column has been increasing in South Korea by 0.16 × 10¹⁵ molecules/cm²/year (1.56 % per year) during summer months, correlated with the increasing incidences of drought. HCHO increase is linked to higher ozone as most of South Korea is in the NOx-saturated or transitional regime.