Role of ground and excited singlet state oxygen in the red light-induced stimulation of Escherichia coli cell growth.
Irradiation of selected Escherichia coli defective strains with red-light induces a stimulation of the cell growth rate. Such effect is wavelength-dependent and is accompanied by a transient increase of the cell volume and some enzymic activities. The presence of oxygen appears to be essential for the occurrence of a significant photostimulatory effect. The results obtained upon irradiation in the presence of quenchers (tryptophan, histidine, azide) or enhancers (deuterium oxide) of singlet oxygen (1O2) strongly suggest that this activated oxygen derivative is generated by excitation of endocellular chromophores (possibly cytochromes). The reaction of 1O2 with nearby cellular targets could induce a sublethal cell damage which in turn promotes an accelerated cell metabolism.
Polo
L
L
Department of Biology, University of Padova, Padova, Italy. polo@civ.bio.unipd.it
Presti
F
F
Schindl
A
A
Schindl
L
L
Jori
G
G
Bertoloni
G
G
D001386:Azides / Q000494:pharmacology; D017666:Deuterium Oxide / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development* / Q000528:radiation effects*; D006639:Histidine / Q000494:pharmacology; D007834:Lasers; D008027:Light; D009243:NAD / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D018462:Photobiology; D026082:Singlet Oxygen; D013997:Time Factors; D014364:Tryptophan / Q000378:metabolism / Q000494:pharmacology; D014867:Water
D001386:Azides; D014867:Water; D009243:NAD; D026082:Singlet Oxygen; D006639:Histidine; D014364:Tryptophan; D009245:NADH Dehydrogenase; D017666:Deuterium Oxide; D010100:Oxygen