Induction of Pigmentation in Nonproliferating Cells of Serratia marcescens by Addition of Single Amino Acids

Abstract

Addition of casein hydrolysate to suspensions of washed, nonpigmented, nonproliferating Serratia marcescens incubating at 27 C induced biosynthesis of prodigiosin. Four amino acids of casein hydrolysate, DL-aspartic acid, L-glutamic acid, L-proline, and L-alanine caused formation of pigment when added individually. DL-Ornithine also was effective. Optimal concentrations for maximal pigmentation were 5 to 10 mg/ml; at these high concentrations, D-serine also induced biosynthesis of some prodigiosin. DL-Alanine and -ornithine were as effective as the Liosomers, but L-glutamic acid and L-proline gave better responses than their racemic mixtures. Kinetics of prodigiosin biosynthesis after addition of DL-alanine (20 mg/ml) were similar to those of cells suspended in 0.2% casein hydrolysate. The other amino acids were less effective. Addition of 5 mg of DL-alanine or casein hydrolysate per ml to minimal medium increased by 30% the amount of prodigiosin formed by growing cells after incubation for 7 days at 27 C. Cultures grown for 7 days at 27 C in 0.2% casein hydrolsate formed more prodigiosin than did suspensions of nonproliferating cells containing individual amino acids or casein hydrolysate. However, more pigment was produced by cells suspended in L-alanine (5 mg/ml) or L-proline (10 mg/ml) than when suspended in 0.4% natural or synthetic casein hydrolysate. Filtrates from suspensions of nonproliferating cells forming pigment in L-proline induced more rapid formation of prodigiosin, but filtrates from suspensions in DL-alanine did not. The data supported the hypothesis that pyrrole groups of prodigiosin may be synthesized from 5-carbon amino acids such as proline, ornithine, aspartic, and glutamic acids, but the role of alanine is unknown.on August 1, 2020 by guest

Effect of Iron and Salt on Prodigiosin Synthesis inSerratia marcescens

“…Quantitative studies on the requirement of iron for growth and prodigiosin synthesis required the development of a chemically defined medium low in iron but capable of supporting good growth and pigment formation when iron was added. Medium GA was developed as a result of experiments with modifications of Bunting's medium (2) while taking into account observations on the induction of pigmentation by single amino acids (16) and the inhibition of pigment synthesis by high phosphate concentrations (3,4,15). Medium GA contained (per liter of distilled water): glycerol (Mallinkrodt, AR), 5.0 ml; L-alanine (Ajinimoto Co., Tokyo), 5.0 g; K,HPO4 (Baker, AR), 0.1 g; and MgSO4 (Mann-Schwarz enzyme grade), 0.1 g. The pH was 7.2 to 7.3 after autoclaving.…”

Role of Methionine in Biosynthesis of Prodigiosin bySerratia marcescens

“…The role of methionine in biosynthesis of prodigiosin was unsuspected until our previous report (14). Certain other amino acids caused biosynthesis of the pigment in nonproliferating bacteria (20), and the "C-label from some was incorporated into prodigiosin formed by growing cells of S. marcescens (13,17,18).…”

“…x g for 20 min, yielding a clear supernatant fluid (S2) and a residue (R). Fraction R, was suspended in saline and dialyzed for 24 h at 2 C against 20 comi Ci were the-X evaporated to dryness in a vacuum rotoevaporator and then was treated with an excess of diazomethane (9). After 10 min, the diazomethane was evaporated, and the methylated pigment (prodigiosin) was purified as described below.…”

Clinical relevance and virulence factors of pigmented Serratia marcescens

“…Factors, such as medium composition [2] and oxygen supply [3], a¡ect the production of prodigiosin and the incubation at 37³C may inhibit the pigmentation [4].…”