Acts as an orphan toxin which is important for maintaining cell fitness during stress related to the stringent response (decreased amino acid, purine and thymidine availability). Overexpression inhibits cell growth and increases the formation of persister cells. Causes 99.9% of cells to undergo bacterial lysis within 2 hours after induction; nucleoids condense, the cytoplasm seems empty and the periplasmic space enlarges. The intracellular ATP level decreases about 27-fold suggesting the membrane potential may be disrupted. By conditions that induce the stringent response such as increased expression of RelA, heat shock at 43 degres Celsius, probably under control of sigma factor E and/or H (rpoE, rpoH), or growth in the presence of trimethoprim (TMP), mupirocin or serine hydroxamate. Strongly represses cell swarming but no effect on cell swimming (PubMed:17122336). Increased metabolic activity in the presence of TMP, an inhibitor of dihydrofolate reductase (folA) and sulfamethoxazole, an inhibitor of dihydropteroate synthetase (folC). Cells grow faster than wild-type in the presence of TMP. Although this protein has high homology to GhoT, the toxic component of a type IV toxin-antitoxin system, no antitoxin has been found. GhoS (the antitoxin for GhoT), YdcY (the neighboring gene), 5'- and 3'-UTRs as well as approximately 620 bp lengths of the BW25113 genome DNA were tested. Belongs to the GhoT/OrtT toxin family.