Abstract: The invention relates to methods for identifying nucleic acid molecules that encode mitochondrial divalent cation transporter polypeptides, which in preferred embodiments are mitochondrial calcium uniporters. Preferred methods employ host cells for expression screening of nucleic acid libraries encoding candidate cation transporters, where the host cells comprise a mitochondrially targeted divalent cation-sensitive indicator molecule. In certain preferred embodiments host cells comprise a mitochondrially targeted esterase that is capable of cleaving a divalent cation sensitive indicator molecule precursor to provide a divalent cation sensitive indicator molecule, or an expression construct directing the expression of such esterase. Host cells that lack endogenous calcium uniporter activity, or that exhibit impaired cell growth in the presence of cytostatic Ca2+ concentrations, are also described.

Abstract: Potent, specific inhibitors of phospholipase A.sub.2 are disclosed which are compounds of the formula: ##STR1## wherein A is R.sub.1 CO.sub.2 or OH, B is R.sub.2 CO.sub.2 or OH, D is R.sub.3 CO.sub.2 or OH and C is R.sub.4 CO.sub.2 ; and wherein R.sub.1, R.sub.2, and R.sub.3 and R.sub.4 are each C.sub.10 -C.sub.30 alkyl groups comprising from about 0-3 double bonds.

Abstract: Halo-A-23187 derivatives, prepared by reaction of antibiotic A-23187 with an N-halo-type halogenating agent, and salts thereof, which are (1) useful biochemical tools for the study of transport of ions in cellular systems, (2) useful chemical tools for removal and recovery of ions, and (3) potential cardiotonic agents.