<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A polyether antibiotic isolated from Streptomyces conglobatus sp. nov. Trejo with antineoplastic activity. Ionomycin is a calcium ionophore that increases intracellular Ca++ levels, possibly relating to endonuclease activation of lymphocytes and decreased ratio of Bcl-2 to Bax and ultimately apoptosis. In addition, this agent is used to investigate the role of intracellular calcium in cellular processes. (NCI)</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>