UVA radiation could be a significant contributor to sunlight inactivation of SARS-CoV-2

Past experiments demonstrated SARS-CoV-2 inactivation by simulated sunlight; models have considered exclusively mechanisms involving UVB acting directly on RNA. However, UVA inactivation has been demonstrated for other enveloped RNA viruses, through indirect mechanisms involving the suspension medium. We propose a model combining UVB and UVA inactivation for SARS-CoV-2, which improves predictions by accounting for effects associated with the medium. UVA sensitivities deduced for SARS-CoV-2 are consistent with data for SARS-CoV-1 under UVA only. This analysis calls for experiments to separately assess effects of UVA and UVB in different media, and for including UVA in inactivation models.Lay summaryRecent experiments have demonstrated that SARS-CoV-2 is inactivated by simulated sunlight; however, there are still many unknowns, including the mechanism of action and which part of the light spectrum is principally responsible. Our analysis indicates the need for targeted experiments that can separately assess the effects of UVA and UVB on SARS-CoV-2, and that sunlight inactivation models may need to be expanded to also include the effect of UVA. A first UVA-inclusive model is also proposed here. These findings have implications for how to improve the safety of the built environment, and for the seasonality of COVID-19.

Enhanced Alkaloid Production from Cell Culture System of Catharanthus roseus in Combined Effect of Nutrient Salts, Sucrose and Plant Growth Regulators

Callus and biomass culture of Catharanthus roseus L. were established to check for the presence of total alkaloid and its subsequent yield. Various treatments like strength of nutrient salts, sucrose concentrations and combinations of plant growth regulators (PGR’s) were applied to both MS and B5 in agar as well as suspension medium to test their effects on enhanced alkaloid content and its yield. There was no significant difference in any of the observable parameters of fresh wt, dry wt, alkaloid content, production, productivity and yield if the culture were treated similarly in both types of media formulations (MS or B5 salts). Physical state (agar solidified or the liquid suspension) of the medium had significant effect on all the parameters particular on fresh wt, alkaloid content and yields. Although, the fresh wt. and dry wt. of biomass in suspension culture was 2-3 times less than that of callus obtained from agar medium. However, the alkaloid content and yield was 2-3 times higher in suspension culture compared to agar medium in similar treatments. The highest alkaloid content observed was 5.67mg/g dwt in B5 suspension medium containing 3% sucrose and modified with 0.5mg/l 2,4-Dichlorophenoxy acetic acid (2,4-D) + 1 mg/l Kinetin (KIN) + 2mg/l α- naphthalene acetic acid (NAA). The combined effects of these factors on the enhanced production of total alkaloids were expected to contain higher yield of anticancer vinblastine and vincristine in the cell suspension culture system.

Optimization of a liquid chromatography-tandem mass spectrometry method for the quantification of traces of taxanes in a Corylus avellana cell suspension medium

We developed a reliable HPLC-MS/MS method to quantify five of the most commercially important taxanes in a C. avellana cell suspension medium. Its linearity, intra- and inter-day precision, recovery, accuracy, LOD/LOQ and matrix effect were evaluated.