Summary UCSC proposes to purchase a Beckmann and Coulter CytoFLEX LX cell analyzer with 6 lasers (UV, violet, blue, yellow-green, red, far red) and a plate-loader accessory. Our current, aging, 3-laser LSR II flow cytometer must be replaced, because maintenance for that model will be discontinued in 2021. Additionally, most users require a modern cell analyzer that offers more colors for cell analysis, as well as the small sample volume and high throughput afforded by the plate-loader. The CytoFLEX LX cell analyzer will allow users to interrogate individual cells that are labeled with up to 20 different fluorophores at once. The plate loader will streamline the analysis of multiple samples and reduce the required sample volume significantly from 4-mL sample tubes to wells in a 96-well plate. The small sample volume is particularly important for our many stem cell researchers who often work with very rare, primary cells. Major users will rely on this new instrument to advance important biomedical issues in their NIH-funded research grants, including investigations of: a) age-induced changes in blood stem cells and implications for geriatric ailments, b) the role and regulation of a novel, developmentally restricted hematopoietic stem cell, c) the role of the long non-coding RNA GAPLINC in septic shock and inflammation, and d) the mechanisms governing cell fate acquisition and alveologenesis in the mammary gland. Minor users will address diverse biomedical problems, such as establishing the details of bacterial pathogen infections, the regulation of stem cell differentiation in human development, cell membrane permeability for drugs, and peptides, and the functional characterization of natural products for drug development. The proposed instrument will be housed in UCSC’s Cytometry Core facility, which was established in 2007. Instrument supervision, training, maintenance scheduling, and recharge accounting for use of the proposed instrument will be assured by our Cytometry Core Facility manager, whose salary is guaranteed by the UCSC.