Abstract
Many concrete wall surfaces that lack nutrients, water, and solar-UV protection represent an extreme environment for life. In this study, sands were sampled from nine different weathered concrete wall surfaces for viable bacterial count. Most counts were around 104 CFU/g or less. A yellow-pigmented bacterium (THY1) that appeared to be a predominant inhabitant in the harsh concrete-surface environment was isolated. An UV irradiator that provides broad-spectrum UV radiation (encompassing UVA, UVB, and UVC) was used to compare UV radiation (UVR) resistance of different bacterial strains. The results of the UVR survival suggested that THY1 possesses novel UVR-inducible UVR resistance that was not observed in Escherichia coli and Micrococcus luteus. SDS-PAGE analysis suggested the presence in THY1 of two~ 30 kDa UVR-inducible proteins.