Isolation and biological activity of thielocins: novel phospholipase A2 inhibitors produced by Thielavia terricola RF-143.

Thielocins A2 alpha, A2 beta, A3, B1, B2 and B3 were isolated as a novel family of phospholipase A2 inhibitors from the fermentation broth of Thielavia terricola RF-143 together with thielavins and thielocins A1 alpha and A1 beta. The most potent inhibitory activity (IC50 = 0.0033 microM) against rat group II phospholipase A2 was shown by thielocin A1 beta.

Structures of new peptide antibiotics, plusbacins A1-A4 and B1-B4.

The constituent amino acids of plusbacins A1-A4 were determined to be two moles of L-trans-3-hydroxyproline and one mole each of D-threo-beta-hydroxyaspartic acid, L-threo-beta-hydroxyaspartic acid, D-allo-threonine, D-serine, D-alanine and L-arginine. In plusbacins B1-B4, one mole of L-trans-3-hydroxyproline is replaced by L-proline. The fatty acid residue of A1 and B1 was determined to be 3-hydroxy-tetradecanoic acid, for A2 and B2 to be 3-hydroxy-isopentadecanoic acid, for A3 and B3 to be 3-hydroxy-isohexadecanoic acid, and for A4 and B4 to be 3-hydroxy-hexadecanoic acid.

Isolation and characterization of new peptide antibiotics, plusbacins A1-A4 and B1-B4.

New antibiotics, plusbacins A1-A4 and B1-B4, were isolated from the culture broth of a strain of Pseudomonas sp. These antibiotics were isolated as a complex by column chromatographies on Diaion HP-20 and silica gel, and then separated by HPLC. They are amphoteric in nature.

Structures of cepafungins I, II and III.

Structures of interesting acylpeptide antibiotics cepafungins I, II and III were elucidated by NMR spectroscopic studies and some degradation experiments. The antibiotics contain a common peptide part that consists of threonine and two unusual amino acid residues, gamma-hydroxylysine and 4-amino-2-pentenoic acid. The unusual amino acid residues compose an interesting 12-membered ring with an exocyclic N-terminus to which the threonine is connected.

Isolation of cepafungins I, II and III from Pseudomonas species.

New acylpeptide antibiotics named cepafungins I, II and III were isolated from the culture broth of a strain identified as Pseudomonas sp. These antibiotics are neutral substances, soluble in aqueous alcohols and dimethyl sulfoxide, and show UV maxima at 260.5 nm.