ChemInform Abstract: Aborycin ‐ A Tricyclic 21‐Peptide Antibiotic Isolated from Streptomyces griseoflavus.

Abstract

The screening for growth inhibitors against Bacillus subtilis revealed a peptide antibiotic produced by Streptomyces griseoflavus TU 4072. Very high yields of the antibiotic named aborycin were obtained by cultivation in a medium containing soybean meal and sucrose. Isolation from the mycelium was carried out by a combination of extraction and gel chromatography. Preparative HPLC yielded the uniform antibiotic. The structure elucidation was based on GC amino acid analysis on a chiral phase, automated Edman degradation,The Streptomyces griseoflavus strain TU 4072 was isolated from a soil sample collected in Alice Springs, Australia. Due to this origin of the producing strain the isolated antibiotic was named aborycin. Cultivation using soybean meal as nitrogen source and sucrose as carbon source gave high yields of aborycin. For the isolation of the antibiotic the aqueous methanolic extract of the mycelium was first extracted with ethyl acetate and then with l-butanol. Gel chromatography of the 1-butanol extract followed by preparative HPLC gave 271 mg of pure aborycin out of 5 liters of culture broth. After treatment with Ehrlich's reagent the antibiotic gave a blue spot on TLC plates (Rf = 0.47, 1-butanoYethanoVwater, 6:2:2). The Rf value was similar to the one of tryptophan. Aborycin inhibited the growth of Bacillus subtilis ATCC 6633 at a minimum inhibition concentration (MIC) of 20 pg/ml, Bacillus brevis ATCC 9999 (MIC 25 pglml), Staphylococcus aureus ETH 2070 (MIC 15 pglml), Pseudomonas saccharophila ATCC 15946 (MIC 15 pg/ml), and of Streptomyces viridochromogenes TU 57 (MIC 2 pglml) but was inactive against Escherichia coli K12, Salmonella typhimurium TU 5108, Mucor hiemalis TU 179/180, Mucor miehi TU 284, and Yarrowia lipolytica TU 5054.

Lasso Peptides: An Intriguing Class of Bacterial Natural Products

“…34 Supplementary Table S1). [1][2][3][4][5][6][7][8][9][10][11][12][13][14]16,17,19,20,32,33 In general, all so far known lasso peptides originated from either proteobacterial or actinobacterial sources (Figure 4), even though genome mining approaches have revealed putative biosynthetic gene clusters in other phyla as well. 21,26−28 The biological activities hitherto identified for lasso peptides encompass a wide variety of functions ( Figure 2).…”

In silico Screening Unveil the Great Potential of Ruminal Bacteria Synthesizing Lasso Peptides

“…Lasso peptide production has been mainly associated with members of the phyla Actinobacteria and Proteobacteria and the best-studied molecules of this family are produced by representative species within these phyla ( Weber et al, 1991 ; Salomon and Farías, 1992 ; Helynck et al, 1993 ; Potterat et al, 1994 ; Tsunakawa et al, 1995 ; Kimura et al, 1997 ; Knappe et al, 2008 ; Hegemann et al, 2013a ). Moreover, genome-guided studies focused on natural product discovery often point to these bacterial phyla as promising sources of lasso peptides ( Severinov et al, 2007 ; Hegemann et al, 2013b ; Maksimov and Link, 2014 ).…”

Lasso Peptides

“…Lasso peptides produced by actinobacteria are generally active against Gram-positive bacteria, while those produced by proteobacteria show a narrow spectrum of activity directed against bacteria closely related to the producing strain. Propeptin and aborycin constitute exceptions to this trend, being active on both Gram-positive and Gram-negative bacteria such as Pseudomonas (Potterat et al 1994;Kimura et al 1997a). Antimicrobial assays showed that propeptin (Kimura et al 1997a), capistruin ) and astexin-1 have only a weak activity and no significant activity is noticed for anantin (Weber et al 1991), sungsanpin (Um et al 2013), caulosegnins ) and xanthomonins ).…”