Comparative photoreactivation of ultraviolet light-inactivated tobacco mosaic virus ribonucleic acid on Chenopodium, pinto bean, and tobacco plants

Irradiation of UVC LED at 277 nm inactivates coronaviruses in association to photodegradation of spike protein

To interrupt SARS-CoV-2 transmission chains, Ultraviolet-C (UVC) irradiation has emerged as a potential disinfection tool to aid in blocking the spread of coronaviruses. While conventional 254-nm UVC mercury lamps have been used for disinfection purposes, other UVC wavelengths have emerged as attractive alternatives but a direct comparison of these tools is lacking with the inherent mechanistic properties unclear. Our results using human coronaviruses, hCoV-229E and hCoV-OC43, have indicated that 277-nm UVC LED is most effective in viral inactivation, followed by 222-nm far UVC and 254-nm UVC mercury lamp. While UVC mercury lamp is more effective in degrading viral genomic content compared to 277-nm UVC LED, the latter results in a pronounced photo-degradation of spike proteins which potentially contributed to the higher efficacy of coronavirus inactivation. Hence, inactivation of coronaviruses by 277-nm UVC LED irradiation constitutes a more promising method for disinfection.

In vitro photoreactivation of ultraviolet-inactivated ribonucleic acid from tobacco mosaic virus

Abstract— Treatment of ultraviolet‐inactivated tobacco mosaic virus ribonucleic acid (TMV–RNA) with extracts obtained from the local lesion host, Nicotiana tabacum var. Xanthi, n.c., and simultaneous illumination at 365 nm results in up to a four‐fold increase in infectivity over non‐illuminated controls. The active material in the extract appears to be associated with protein, based on its inactivation by boiling, precipitation with ammonium sulfate, and exclusion from Bio‐Rad P100 polyacrylamide. Partially purified DNA photoreactivating enzyme from yeast or pinto bean has no activity on ultraviolet‐irradiated TMV–RNA.

Light-mediated regulation of TMV-RNA photoreactivation

Abstract— –Nicotiana tabacum var. Xanthi n.c. plants placed in the dark lose their ability to photoreactivate u.v.‐irradiated tobacco mosaic virus RNA over a course of approximately 1 week. When such plants are returned to the light, they recover their photoreactivation ability. The recovery occurs after a lag of at least 3 hr and is complete in 12–24 hr. Three hours or less of cool‐white illumination (2400 ft‐c) are necessary to induce recovery. Blue light is effective in inducing recovery; green light is less effective; red and near‐u.v. are not effective.