Degree of ultraviolet radiation damage and repair capabilities are related to G+C content in marine vibriophages

Abstract

A key issue in the ecology of viruses in the marine environment is the rate of viral production and decay. The ultraviolet (UV) radiation in sunlight has been found to cause loss of infectivity in marine bacteriophages at rates nearly equal to all other decay mechanisms combined. There are 2 main host-mediated mechanisms that can repair UV-damaged phage DNA: photoreactivation and excision repair. Both these mechanisms were investigated in 2 marine Vibrio parahaemolyticus hosts as they catalyzed the reactivation of 7 phages. Photoreactivation was the dominant repair mode in all but one case. A significant correlation was found between G+C content of the phage DNAs (16 to 70%) and degree of DNA damage (r = 0.955), indicating a strong relationship between the number of thymine dimer targets and the capability to photoreactivate DNA damage. Evolution of high G+C content may be a strategy for protection from UV damage in marine phages.

Factors affecting virus dynamics and microbial host-virus interactions in marine environments

“…However, these differences have yet to be demonstrated for marine viruses. Interestingly, Kellogg & Paul () found a significant negative correlation between the G+C content of marine phage DNA and the degree of DNA damage induced by solar radiation. Viruses with AT‐rich genomes and thus higher potential dimer (T‐T) sites had a higher potential for UV damage (Kellogg & Paul, ).…”

“…Interestingly, Kellogg & Paul () found a significant negative correlation between the G+C content of marine phage DNA and the degree of DNA damage induced by solar radiation. Viruses with AT‐rich genomes and thus higher potential dimer (T‐T) sites had a higher potential for UV damage (Kellogg & Paul, ). In addition, AT‐rich DNA also enhances the generation of oxygen species, which cause oxidative damage (Wei et al ., ).…”

Solar radiation-driven decay of cyanophage infectivity, and photoreactivation of the cyanophage by host cyanobacteria

“…One explanation for this phenomenon is that the UV radiation is rapidly balanced by some resistance mechanisms. The sequence, structure, and genomic size of the DNA may contribute to the sensitivity and the resistance to damage (Garza & Suttle 1998, Wilhelm et al 1998, Kellogg & Paul 2002, Jacquet 2003.…”

“…native virus isolates degrade more slowly in full sunlight than non-native marine bacteriophages (Garza & Suttle 1998), or UV-sensitive organisms may grow and divide quickly to 'dilute' the phototoxicity (Hader & Sinha 2005). Active mechanisms include photoreactivation, excision repair, recombination repair, and mutagenesis, of which photoreactivation is the easiest and the most efficient (Kellogg & Paul 2002, Sinha & Hader 2002. Photolyase, the enzyme that catalyses the reaction, represents one of the simplest and most classical systems that exists in various organisms, including cyanobacteria (Sancar 1996).…”

UV-induced DNA damage in coral reef fish: damage levels and protection mechanisms

“…In other studies differences in sensitivity to UVR between species has been attributed to differences in pyrimidine base composition (Kellogg & Paul 2002) and variation in anthropogenic influences such as deforestation of habitats along the distribution of a species (Mitchell et al 2014). Since the genetic sequences of the species studied here are yet unknown and there was only a single location (Lizard Island) were fish were collected, the specific factors influencing the higher and lower levels of DNA damage in these species remain to be determined in future studies.…”