Project Summary We are requesting supplemental funds to the parental grant R35GM119569 to purchase a Beckman-Coulter ultracentrifuge (Optima XE-100 IVD) and two rotors (45Ti and SW32Ti). The Ascano laboratory routinely utilizes density gradient ultracentrifugation as a means of concentrating viruses and isolating them from cellular debris during propagation. However, the current ultracentrifuge (Beckman Optima LE-80K) is over 19 years old (was purchased in 2003) and has had to be serviced twice in the last two years, during which it experienced significant downtimes because replacement parts for an obsolete piece of equipment are harder to source – as communicated by Beckman repair technicians servicing the instrument. Given its age, the costs to repair the current instrument only continue to increase. Moreover, the two rotors that the lab currently use, a 45Ti and a SW32Ti, are also older - with the newest one (SW32Ti) being purchased in 2014; both rotors are no longer under warranty. We are principally requesting funds to secure a new instrument, in anticipation of the inevitable decommissioning of the current departmental ultracentrifuge. An ultracentrifuge is a mission-critical piece of equipment enabling the laboratory to isolate and concentrate various RNA viruses to high titer and purity. This is a necessary and essential step for preparing one of our most important biological reagents, which we require for three of four research directions of the R35 parental grant.