We propose to acquire a recently developed, dually configured confocal microscope (the LSM 5 Duo, Zeiss)? to support the research of a group of 9 NIH-funded investigators at the University of Maryland School of? Medicine. These investigators each have immediate need for high-speed, multi-color fluorescence confocal? imaging during photoactivation, photobleaching, or long-distance Z motion. No equipment with the required? capabilities exists on campus. The Zeiss Duo combines the well-established, high-resolution optical? sectioning capabilities of the LSM 510 with the high-speed imaging capabilities of the more recent LSM? 5Live. The two, independent beam-steering systems of the Duo create the synergistic capacity for? simultaneous region-of-interest photomanipulation during rapid image acquisition. The Major Users each? confirmed that the capabilities of the Duo directly and uniquely well meet their requirements. The new? instrument will be incorporated into the long-standing Confocal Core Facility at the University, where it will? replace an LSM410 that was purchased in 1994 and is neither suitable nor reliable for the live-cell? experiments that now occupy the large majority of time on the confocal microscopes in the Facility. After? evaluating possible system configurations from the major vendors, the Facility?s oversight committee also? agreed that the Duo presented the only configuration that would meet the increasing demand for highspeed,? live-cell imaging while providing consistent access to a high-resolution point-scanning confocal.? Accordingly, institutional support is very strong at the Dean?s level and also spread widely among many? Departments with extensive NIH-supported research. The presence of the Duo in the Confocal Core? Facility would directly and strongly benefit the research of the Major Users; more broadly, it would add an? important new capability for advancing the NIH-sponsored research of the many other investigators on? campus studying biological processes in living cells and systems.