MDS Inc. said this morning that it is acquiring Sunnyvale-based Molecular Devices in a $615M deal. Molecular Devices is a provider of measurement tools for cellular analysis and biochemical testing. The deal is all-cash, and is worth $35.50 per share of Molecular Devices stock. According to the firms, Molecular Devices had revenues of $185M for the four quarters ending September 2006. MDS was advised by Merrill Lynch & Co., and Ropes & Gray LLP; Molecular Devices was advised by UBS Investment Bank and Cooley Godward Kronish LLP.