[Influence of supplementary tyrosine or phenylalanine on bacterial growth and pigmentation of "Pseudomonas aeruginosa" (author's transl)].

Pseudomonas aeruginosa grows readily on synthetic media containing succinate (36 mM) and ammonium chloride as sole source of nitrogen (34 mM) ; addition of tyrosine or phenylalanine (2,7 mM) is followed by an increase of both the growth rate and pyocyanine production. Several molecules structurally related to tyrosine give similar results. Tyrosine partially suppresses the inhibitory effect of both cyanide and azide.

[The effect of zinc and cobalt ions on the chromogenesis of Pseudomonas aeruginosa in the presence of methylphosphonic acid].

Adding zinc or cobalt sulphate into synthetic culture media of Pseudomonas aeruginosa was followed by partial or total inhibition of pyocyanine production, varying with the nature of the chemical source of phosphorus. An antagonism between Zn2+ and Co2+ ions was shown.