The Aldehyde Content of Luminous Bacteria and of an “Aldehydeless” Dark Mutant

Fatty aldehydes, present in the luminescent cells of Photobacterium phosphoreum and Achromobacter fischeri, and to a very slight extent in the cells of a visually dark, "aldehydeless" mutant of the latter species, were extracted, purified, and oxidized to the corresponding acids. The acids were analyzed by mass spectrometry. The results, in conjunction with various other lines of evidence, indicate that saturated fatty aldehydes, comprising mostly dodecanal, tetradecanal, and hexadecanal, function in the bioluminescent reaction in living cells of these luminous bacteria. The amount of these aldehydes in the cells was computed to be sufficient to sustain steady-state luminescence for a period of about 1 sec, and under such conditions the rate of oxidation of the aldehydes in the process of luminescence must be balanced by their rate of production.