A tetronic acid related to saccharocarcin, chlorothricin, versipelostatin and tetrocarcin; contains an unusual nitroaminoglycoside; a potent antibacterial, antimalarial and antitumour active; inhibits transcription from the promoter of GRP78, a gene that is activated as part of a stress signalling pathway under glucose deprivation resulting in unfolded protein response (UPR).