Effect of Iron and Salt on Prodigiosin Synthesis inSerratia marcescens

Abstract

Serratia marcescens wild-types ATCC 264 and Nima grew but did not synthesize prodigiosin in a glycerol-alanine medium containing 10 ng of Fe per ml. Wild-type 264 required the addition of 0.2 Ag of Fe per ml for maximal growth and prodigiosin synthesis; Nima required 0.5 ,g of Fe per ml. Three percent, but not 0.1%, sea salts inhibited prodigiosin synthesis in a complex medium containing up to 10 ,g of Fe per ml. NaCl was the inhibitory sea salt component. The inhibition was not specific for NaCl; equimolar concentrations of Na2SO4, KCl, and K2SO also inhibited prodigiosin synthesis. Experiments with strains 264 and Nima and with mutant WF which cannot synthesize 4-methoxy-2-2'bipyrrole-5-carboxaldehyde (MBC), the bipyrrole moiety of prodigiosin, and with mutant 9-3-3 which cannot synthesize the monopyrrole moiety 2-methyl-3amylpyrrole (MAP) showed that both MBC synthesis and the reaction condensing MAP and MBC to form prodigiosin were relatively more sensitive to NaCl inhibition than the MAP-synthesizing step. The capacity of whole cells to condense MAP and MBC was present, but inactive, in cells grown in NaCl; removal of the NaCl from non-proliferating salt-grown cells restored the activity. Other evidence suggests the existence of a common precursor to the MAP-and MBCsynthesizing pathways.Apollo 11 lunar material in a medium containing 0.1% (wt/vol) sea salts had no detectable effect on the growth of a number of terrestrial microorganisms (12). However, fluorescent pigment formation by Pseudomonas aeruginosa ATCC 15422 was inhibited, whereas synthesis of the red pigment prodigiosin by Serratia marcescens ATCC 264 was stimulated. These effects were traced to iron leached from the lunar material. It was also observed that increasing the concentration of sea salts in the growth medium from 0.1 to 3% prevented prodigiosin synthesis in the presence of lunar material. Although iron is required for prodigiosin synthesis (1, 2, 5), only Waring and Werkman (13) have reported quantitative data. In addition, the literature appears devoid of any reports on salt inhibition of prodigiosin biosynthesis. This paper reports the results of further studies on the iron requirements for growth and prodigiosin synthesis in S. marcescens, identification of NaCl as the component in sea salt responsible for inhibition of prodigiosin synthesis, and the location and apparent mechanism of action of the NaCl block in the terminal biosynthetic pathway of the pigment. MATERIALS AND METHODSOrganisms. The wild-type strains of S. marcescens used in this study were ATCC 264 (obtained from H. S. Ginoza) and Nima (kindly supplied by R. P. Williams). Mutants 9-3-3 and WF were also supplied by R. P. Williams. Mutant 9-3-3 is blocked in the synthesis of the volatile monopyrrole moiety of prodigiosin, 2-methyl-3-amylpyrrole (MAP), but produces the stable bipyrrole moiety, 4-methoxy-2-2'-bipyrrole-5-carboxaldehyde (MBC). Mutant WF is blocked in the synthesis of MBC, but produces MAP. Both mutants and the two wild types can couple MBC and MAP to form ...

Influence of Environmental Factors and Medium Composition on Vibrio gazogenes Growth and Prodigiosin Production

“…The effect of iron on prodigiosin biosynthesis by S. marcescens has long been recognized (15,17,18), but its specific role in the system is still unknown. Under normal culture conditions for V. gazogenes, 8 mg of ferric iron per liter is used, which is in the concentration range proven to be optimal for cell growth and pigment synthesis.…”

“…Under normal culture conditions for V. gazogenes, 8 mg of ferric iron per liter is used, which is in the concentration range proven to be optimal for cell growth and pigment synthesis. In S. marcescens cultures, more ferric iron is required for prodigiosin biosynthesis than for growth (15).…”

Isolation and characterization of a microbial pigment obtained from Serratia marcescens as a natural food colourant

“…It was found, when tryptone and yeast extract were increased, that there was a profound increase in pigment yield, especially when sodium chloride (NaCl) levels were reduced, suggesting that NaCl may pose an inhibitory effect on pigment production. The presence of excessive NaCl concentrations are said to stop or slow down the activity of condensing enzymes which is responsible in the regulation of the terminal condensation step in prodigiosin production (Silverman and Munoz, 1973). pH pH influences production of prodigiosin by either affecting the nutritional properties of the media such as the solubility of the nutrients, transportation, and ionization, in addition to influencing the overall stability of the pigment.…”

Decrease in Respiration Activity Related to Prodigiosin Synthesis in Serratia marcescens

“…A recent attempt to clone the genes for the pigment synthesis was not completely successful (4). Physiological approaches show that prodigiosin synthesis occurs at the postexponential phase (19) and is influenced by some cultural conditions, such as incubation temperature (20), medium composition (3,7,16,22), pH (1), and oxygen supply (20). Williams and Qadri stated that under these cultural conditions, oxidative metabolism is apparently essential for the biosynthesis of the pigment (21), and, as we reported earlier, the diversity of prodigiosin content in the stationary phase organisms seems to be due to differences in aeration conditions (8).…”