The goal of this proposal is to gain fundamental insights into the action of ultraviolet light on viruses. The study will examine the molecular level viral responses to ultraviolet irradiation to improve current ultraviolet light disinfection and design of future ultraviolet light technologies. The research aims to answer a number of fundamental questions around virus inactivation with ultraviolet light that can inform engineering practice, public health, and subsequent regulatory policy and thus has broad reaching impacts.
The proposed activity will advance knowledge in a number of key areas. New fundamental knowledge will be developed into the molecular-level response of viruses to ultraviolet light irradiation during disinfection practice. Specifically, in addition to adenoviruses, new studies will be performed on another double stranded DNA virus - JC polyomavirus - to test the generalizability of the findings with adenoviruses in response to low-pressure and medium-pressure ultraviolet light. This research will move beyond the traditional evaluations of laboratory strains of adenoviruses and isolate and test environmental strains to determine if there are any differences in the ultraviolet light -response that may be related to acclimated responses (such as DNA repair) from repeated exposure to and propagation in laboratory cell culture lines. A number of new areas in molecular microbiology methods, some of which we have developed, will be exploited including early stage infection inhibition due to specific ultraviolet light wavelengths, DNA repair from trans-lesion synthesis, protein damage assessment using electrophoresis and mass spectrometry techniques, and DNA damage using a new long range PCR technique we recently published. These fundamental findings will be used to develop a tailored wavelength ultraviolet-LED based energy efficient irradiation system to optimize disinfection at lower cost than conventional ultraviolet sources. The work proposed herein will: (1) evaluate inactivation kinetics and wavelength sensitivity of two double stranded DNA viruses, (2) extend the adenovirus studies to adenoviruses isolated from the environment, (3) evaluate the fundamental role of DNA repair in the cell culture infectivity outcomes, (4) incorporate newly developed molecular biology-based assays to assess DNA damage and protein damage from ultraviolet light irradiation at varying wavelengths, and, (5) understand the implications for disinfection using tailored wavelength approaches made possible by the development of nanometer-specific ultraviolet light emitting diodes (LEDs). Regulators and public health officials need information to help make sound decisions for the public sector. The issue of virus disinfection for small systems is currently contentious as the Groundwater Rule specifically forbids the use of UV for any virus inactivation credit due to the high doses required for adenovirus inactivation that cannot currently be field-validated in UV reactors. Therefore, the timing of this research is critical if UV disinfection is going to play any role for virus disinfection in groundwater. Thus, small-systems wanting to use UV for protection of public health, may needlessly suffer.
