ABSTRACT
Dioxolides, a novel class of secondary metabolites were detected by a HPLC-diode array screening technique in the culture filtrate of Streptomyces tendae Tu 4042. The compounds show no biological activity against Gram-positive and Gram-negative bacteria, yeasts and fungi. Besides dioxolides, which consist of an unusual substituted dioxolane ring, anhydroshikimate and para-hydrobenzamide were detected by this technique. Both compounds were not yet described as natural products.
Subject(s)
Streptomyces/metabolismABSTRACT
A new member of the quinoxaline group antibiotics has been detected by HPLC-diode-array screening. The main compound produced by Streptomyces tendae strain Tü 4031 showed a high degree of similarity in the UV-visible spectral region with echinomycin and their structural similarity was confirmed by structure elucidation using electron tandem mass spectrometry and 2D nuclear magnetic resonance. The new compound, named echinoserine, is a non-cyclic form of echinomycin, but it is not a biosynthetic precursor. Echinoserine is less antibiotically active than echinomycin.
Subject(s)
Antibiotics, Antineoplastic/isolation & purification , Echinomycin/analogs & derivatives , Echinomycin/isolation & purification , Antibiotics, Antineoplastic/chemistry , Antibiotics, Antineoplastic/pharmacology , Chromatography, High Pressure Liquid , Echinomycin/chemistry , Echinomycin/pharmacology , Fermentation , Microbial Sensitivity Tests , StreptomycesABSTRACT
The article describes four different fermentation procedures for Escherichia coli AN311, a producer of enterobactin. A regular rotary shaker culture with a biphasic system consisting of an agar layer (as a reservoir for feeding processes) and a layer of liquid medium, 2.4 L and 10 L batch cultures, and a novel dialysis membrane fermentor were used. With the use of this latter fermentor type, the production of enterobactin could be increased by a factor of about 9.5, while growth increased by a factor of 12 compared to the other systems. For the rapid and reliable quantification of the concentration and purity of enterobactin an analytical and preparative high-performance liquid chromatography (HPLC) method was established. The degradation compounds of this siderophore were detected by diodearray and bioassays. A comparison of total catechol production as well as the distribution between enterobactin and its degradation compounds is given.
