Blue LED light promoting the growth, accumulation of high-value isoflavonoids and astragalosides, antioxidant response, and biosynthesis gene expression in Astragalus membranaceus (Fisch.) Bunge hairy root cultures.

The root of Astragalus membranaceus (Fisch.) Bunge is one of the most frequently used herbs in traditional Chinese medicine (TCM) formulae for fighting COVID-19 infections, due to the presence of isoflavonoids and astragalosides associated with antiviral and immune-enhancing activities. For the first time, the exposure of A. membranaceus hairy root cultures (AMHRCs) to different colors of LED lights i.e., red, green, blue, red/green/blue (1/1/1, RGB), and white, was conducted to promote the root growth and accumulation of isoflavonoids and astragalosides. LED light treatment regardless of colors was found beneficial for root growth, which might be a result of the formation of more root hairs upon light stimulation. Blue LED light was found most effective for enhancing phytochemical accumulation. Results showed that the productivity of root biomass in blue-light grown AMHRCs with an initial inoculum size of 0.6% for 55 days was 1.40-fold higher than that in dark (control), and yields of high-value isoflavonoids and astragalosides including calycosin, formononetin, astragaloside IV, and astragaloside I increased by 3.17-fold, 2.66-fold, 1.78-fold, and 1.52-fold relative to control, respectively. Moreover, the photooxidative stress together with transcriptional activation of biosynthesis genes might contribute to the enhanced accumulation of isoflavonoids and astragalosides in blue-light grown AMHRCs. Overall, this work offered a feasible approach for obtaining higher yields of root biomass and medicinally important compounds in AMHRCs via the simple supplementation of blue LED light, which made blue-light grown AMHRCs industrially attractive as plant factory in controlled growing systems. Supplementary Information: The online version contains supplementary material available at 10.1007/s11240-023-02486-7.

Complexation ability of tetrasulfosubstituted cobalt(II) phthalocyanine toward ORF3a protein of SARS-CoV-2 virus.

Complex formation processes of tetrasulfosubstituted cobalt(II) phthalocyanine with ORF3a accessory protein of SARS-CoV-2 coronavirus were studied. The interaction of ORF3a protein with SARS-CoV-2 virus with tetrasulfosubstituted cobalt(II) phthalocyanine affords a stable complex in which metallophthalocyanine exists in the monomeric form. The complex formation induces slight changes in the secondary structure of the protein by increasing the fraction of disordered fragments of the polypeptide chain. The photoirradiation of the complex of ORF3a protein of SARS-CoV-2 virus with tetrasulfosubstituted cobalt(II) phthalocyanine leads to the photooxidation of amino acid residues of the protein.

Molecular Tracer Characterization during COVID-19 Pandemic in Shanghai: Changes in the Aerosol Aqueous Environment and Implications for Secondary Organic Aerosol Formation

The COVID-19 lockdown has opened a unique window for investigating aerosol formation and evolution with controlled anthropogenic emissions in urban areas. Here, variations of PM2.5 chemical compositions, gaseous pollutants, meteorological conditions, and secondary organic aerosol (SOA) molecular tracers were monitored during three stages at an urban site (Pudong) and a suburban site (Qingpu) in Shanghai, which were defined as pre-COVID lockdown (PL), during COVID lockdown (DL), and after COVID lockdown (AL) in 2020. Abundances of pollutants during the same periods back in 2019 were also analyzed for a more comprehensive intercomparison and evaluation of the impact of the 2020 COVID-19 lockdown on regional air quality. With the sudden cessation of anthropogenic activities during the lockdown, significant reductions in PM2.5 were observed compared to both PL in 2020 (32% in Pudong and 36% in Qingpu) and the DL period back in 2019 (31% in Pudong and 35% in Qingpu), which was accompanied by the significantly reduced PM2.5 components (29-44% and 14-44% reductions in sulfate, nitrate, ammonium, organic carbon, and elemental carbon for Pudong and Qingpu, respectively). In particular, with the reduced secondary inorganic aerosol (SIA), the time series of SOA molecular tracers also underwent significant reduction that was characteristic to the lockdown. Amid the uncontrolled biogenic emissions and even slightly enhanced atmospheric oxidation capacity during the 2020 DL period, controlling anthropogenic emissions exhibits synergistic effects on the reduction of SIA and SOA, which could be further attributed to the changes in the aerosol aqueous-phase environment, such as aerosol liquid water content (ALWC), ionic strength, sulfate content, and particulate NH4+. Based on thermodynamic modeling, greatly reduced ALWC was observed during 2020 DL, which can prevent the partitioning of oxygenated organics into the condensed phase as well as the aqueous-phase formation of SOA. Higher ionic strength in 2020 DL may have a "salting-out" effect on gas- particle partitioning of oxygenated organics. The reduced SOA during 2020 DL at both sites can generally be reflected by the predicted heterogeneous reaction kinetics (gamma) of the isoprene SOA formation pathway. Overall, our study showed a synergistic effect in suppressing SIA and SOA formation upon the reduction of anthropogenic emissions during the COVID-19 lockdown, which shed light on the importance of controlling anthropogenic emissions in regulating secondary aerosol formation in typical urban areas of East China.

Variations in Sulfur and Nitrogen Oxidation Rates in Summer Aerosols from 2014 to 2020 in Wuhan, China

To date, research regarding the changes of the sulfur and nitrogen rates in Wuhan during the summer is limited. In this study, we analyzed the air quality in Wuhan, China, using water-soluble ion, gaseous precursor, and weather data. A Spearman correlation analysis was then performed to investigate the temporal changes in air quality characteristics and their driving factors to provide a reference for air pollution control in Wuhan. The results indicate that SO2 in the atmosphere at Wuhan undergoes secondary conversion and photo-oxidation, and the conversion degree of SO2 is higher than that of NO2. During the summers of 2016 and 2017, secondary inorganic atmospheric pollution was more severe than during other years. The fewest oxidation days occurred in summer 2020 (11 days), followed by the summers of 2017 and 2014 (25 and 27 days, respectively). During the study period, ion neutralization was the strongest in summer 2015 and the weakest in August 2020. The aerosols in Wuhan were mostly acidic and NH4+ was an important neutralizing component. The neutralization factors of all cations showed little change in 2015. K+, Mg2+, and Ca2+ level changes were the highest in 2017 and 2020. At low temperature, high humidity, and low wind speed conditions, SO2 and NO2 were more easily converted into SO42− and NO3−.

Visible Light-Generated Antiviral Effect on Plasmonic Ag-TiO2-Based Reactive Nanocomposite Thin Film.

The recent coronavirus pandemic pointed out the vulnerability of humanity to new emerging infectious diseases. Experts warn that future pandemics may emerge more frequently with greater devastating effects on population health and the world economy. Although viruses are unable to propagate on lifeless surfaces, they can retain their infectivity and spread further on contact with these surfaces. The objective of our study is to analyze photoreactive composite films that exert antiviral effects upon illumination. Reactive plasmonic titanium dioxide-based polymeric nanocomposite film was prepared with a thickness of 1-1.5 µm, which produces reactive oxygen species (ROS) under visible light irradiation (λ ≥ 435 nm). These species are suitable for photooxidation of adsorbed organic molecules (e.g., benzoic acid) on the nanocomposite surface. Moreover, high molecular weight proteins are also degraded or partially oxidized in this process on the composite surface. Since the Ag0-TiO2/polymer composite film used showed excellent reactivity in the formation of OH• radicals, the photocatalytic effect on high molecular weight (M = ∼66.000 Da) bovine serum albumin (BSA) protein was investigated. Given that changes in the structure of the protein were observed upon exposure to light, we assumed virucidal effect of the illuminated photoreactive composite film. We tested this hypothesis using an airborne-transmitted herpesvirus. As a result, we obtained a drastic decrease in infection capability of the virus on the photoreactive surface compared to the control surface.