alarmone

a·lar·mone

(ă-lar'mōn),
A biochemical with a synthesis that increases under certain stress conditions (for example, a nutritional deficiency affecting certain enzymes).
[alarm + -mone]

alarmone

A intracellular signalling molecule—e.g., (p)ppGpp—which is synthesised in increased amounts by bacteria subjected to environmental insults (e.g., reduction of amino acids in the culture medium, which alters the “bug’s” metabolism).