Environmental stress has played an enormous role in the evolution and physiology of organisms over time. Microbial ecosystems in particular have responded to environmental stress by developing complex biofilm community structures and novel gene products. The overall objective of this research is to examine changes in microbial gene expression that occur in response to natural and elevated ultraviolet radiation stress. To address this issue we use a two-pronged approach: 1) study a sequenced cyanobacterium with a full-genome DNA microarray available; and 2) examine a natural population of cyanobacteria isolated from a microbial mat community. Microbial mats are complex, multi-species biofilm communities that are often found in habitats with increased exposure to solar radiation.
Exposure to solar radiation poses a significant risk to human health. One of the most lethal effects of sun exposure is skin cancer. There are over 1 million new cases of skin cancer each year, accounting for approximately 40% of all cancers (Saladi and Persaud, 2005; Landis et al., 2000; Gilcrest et al., 1999). Microbes, in particular cyanobacteria, are ideal organisms to examine the effects of solar radiation on cellular physiology due to the extreme nature of many microbial habitats, genetic malleability, and ease of cell culturing. These cyanobacteria-dominated communities may utilize novel molecular and biochemical mechanisms to cope with the effects of natural solar radiation thereby facilitating the development of new protective compounds and products. Biofilms, including microbial mat communities, have emerged as a significant biotechnical tools for the development of novel compounds that are being used as medicines, topical sunscreens, environmental cleaning products, and water purification agents.