Gasotransmitters NO, CO and H2S are the key signaling molecules in both animals and plants. They are generated and regulated enzymaticaly in all biological systems. It is now clear that these compounds act in concert to coordinate the cell responses, but exactly how this interaction is achieved is not known. H2S has effects on the accumulation of both reactive chemical species ROS and RNS and can give rise to the other reactive species. We focus on the genetic and physiological evidences of an interaction between nitric oxide and hydrogen sulfide in the bacterial cell - in regulation of DNA repair gene expression and biofilm formation. The crystalline dinitrosyl iron complexes NO-29 and NO-33 with thiourea as the ligands and tetranitrosyl iron complexes with thiosulfate and tetrazole (TNICthio, TNICtetrazo) were studied first in pure solutions and in the combination with H2S. According to the results of our genetic, physiological and EPR studies we concluded that H2S is not acting as a typical genetic signal in bacteria, but it interacts with the true NO signals to ensure the NO-signaling mechanisms to arrange of stress challenges properly.