Over the past two decades, the University of Texas Medical Branch at Galveston (UTMB) has built a premier infectious disease research program focused on emerging infections and biodefense pathogens in accordance with the NIAID's mission to develop countermeasures for these agents. This success is largely due to a critical mass of world-class researchers and the availability of unique laboratory facilities. In 2003, UTMB was the only academic institution awarded NIAID grants to establish both a Regional Center of Excellence for Biodefense and Emerging Infectious Disease Research and a National Biocontainment Laboratory (NBL) to provide more high containment laboratory space. In addition, with partial support from the NIAID, a toiosafety level 4 (BSL4) laboratory was opened in 2003 (and became operational in 2004) as the first laboratory of its type on a university campus in North America. These facilities provide an opportunity to increase overall research efforts, including the capability to conduct studies on the world's most dangerous pathogens. A critical requirement inherent to the scope of the NIAID's research mission is to share these facilities with regional and national researchers and to provide support services for research that can only be done in these high containment facilities. A reliable biosafety and biosecurity method is essential for sharing and working safely with the highly dangerous agents. Therefore, the overall objective is to procure a Gammacell 220 Excel refurbished research irradiator to provide the most reproducible and controlled method to inactivate these dangerous agents while at the same time preserving their biological properties. An example of use of this instrument will be to inactivate Rift Valley fever virus such that genomic and proteomics analysis can be safely performed outside the BSL4 laboratory. The irradiator will be available for use by NIH-supported UTMB investigators, as well as NIH-supported regional and national investigators. When the NBL is completed in 2008, researchers from that facility will also have access to the irradiator. A representative users' group with 21 funded grants are described, including 14 major (12 of which are NIH- funded) and 7 minor users representing multidisciplinary research projects involving several departments at UTMB. It is important to note that usage of the proposed gamma irradiator will drastically increase as usage of the BSL4 laboratory increases and with the completion of the NBL. The irradiator will be maintained and operated under an advisory oversight committee as a core facility in the Center for Biodefense and Emerging Infectious Diseases at UTMB. Yearly maintenance fees will be charged to Pis and administered through the BSL4 Service Center. The irradiator will significantly enhance the ability of investigators to conduct research safely and more efficiently, as well as protect the community from any threats that may be associated with working with these life-threatening pathogens. ? ?