Prodigiosin Concentration Research Articles

Effects of light conditions on prodigiosin stability in the biocontrol bacterium Serratia marcescens strain B2

Serratia marcescens strain B2 is a potential biocontrol agent that produces the antibiotic pigment prodigiosin. When this strain was incubated under white or blue light conditions (<100 µmol m−2 s−1), prodigiosin concentration in bacterial cells decreased, but growth did not. However, red and far-red light had no effect on prodigiosin concentration in bacterial cells. Purified prodigiosin was degraded under white or blue light conditions but was not degraded under red and far-red light. Because white and blue light appeared to affect the stability of prodigiosin itself, light conditions may affect the suppressive effects of the biocontrol agent S. marcescens strain B2.

Influence of Serratia marcescens Pigmentation on Cell Concentrations in Aerosols Produced by Bursting Bubbles

For eight strains of Serratia marcescens, increased cell concentrations were found in aerosols produced from bursting bubbles, with concentrations ranging from a maximum of ca. 80 times the bulk concentration for pigmented strains 4180, 933, and 274 to a minimum approximately equal to the bulk concentration for nonpigmented strain 8100. The increased cell concentration in the aerosol was suppressed when pigmented strains were grown at 37 degrees C, a temperature at which the pigment prodigiosin is not synthesized, resulting in lower concentrations similar to those of nonpigmented strains. Strains that produce higher concentrations of prodigiosin after 1, 2, 4, and 8 days of growth show increasing concentrations in bubble-produced drops; duplicate cultures grown at 37 degrees C did not show any increases. In four concurrent experiments, cells starved for 24 h showed greater concentrations than nonstarved cells for chromogenic strain NIMA, whereas for nonchromogenic strain WF, starved cells showed greater concentrations in three cases and a decreased concentration in the fourth. Bacterial concentrations in aerosol drops from bursting bubbles appear to be predominantly influenced by the surface condition of the bacterial cell.

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

Vibrio gazogenes ATCC 29988 growth and prodigiosin synthesis were studied in batch culture on complex and defined media and in chemostat cultures on defined medium. In batch culture on complex medium, a maximum growth rate of 0.75 h and a maximum prodigiosin concentration of 80 ng of prodigiosin . mg of cell protein were observed. In batch culture on defined medium, maximum growth rates were lower (maximum growth rate, 0.40 h), and maximum prodigiosin concentrations were higher (1,500 ng . mg of protein). In batch culture on either complex or defined medium, growth was characterized by a period of logarithmic growth followed by a period of linear growth; on either medium, prodigiosin biosynthesis was maximum during linear growth. In batch culture on defined medium, the initial concentration of glucose optimal for growth and pigment production was 3.0%; higher levels of glucose suppressed synthesis of the pigment. V. gazogenes had an absolute requirement for Na; optimal growth occurred in the presence of 100 mM NaCl. Increases in the concentration of Na up to 600 mM resulted in further increases in the concentration of pigment in the broth. Prodigiosin was synthesized at a maximum level in the presence of inorganic phosphate concentrations suboptimal for growth. Concentrations of KH(2)PO(4) above 0.4 mM caused decreased pigment synthesis, whereas maximum cell growth occurred at 1.0 mM. Optimal growth and pigment production occurred in the presence of 8 to 16 mg of ferric ion . liter, with higher concentrations proving inhibitory to both growth and pigment production. Both growth and pigment production were found to decrease with increased concentrations of p-aminobenzoic acid. The highest specific concentration of prodigiosin (3,480 ng . mg protein) was observed in chemostat cultures at a dilution rate of 0.057 h. The specific rate of prodigiosin production at this dilution rate was approximately 80% greater than that observed in batch culture on defined medium. At dilution rates greater than 0.057 h, the concentration of cells decreased with increasing dilution rate, resulting in a profile comparable to that expected for linear growth kinetics. No explanation could be found for the linear growth profiles obtained for both batch and chemostat cultures.

Extraction of Prodigiosin from Blood Plasma and Body Tissues and Its Measurement by Spectrophotometric Analysis

Satisfactory methods have been developed to extract prodigiosin from samples of blood plasma and various body tissues. They depend on the preferential solubility of the dye in petroleum ether or in acid chloroform over that in blood plasma or in tissue fluids. The concentration of prodigiosin in these extracts may be measured accurately by spectrophotometric analysis, using the appropriate wave lengths of the absorption band of the dye in the solvents Amounts as small as 0.1 micrograms per milliliter may be detected in a reproducible manner.