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. Against human group II phospholipase A2, thielocin B3 (IC50 = 0.076 microM) was the most potent.

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. The hydrochlorides are obtained as colorless powders, soluble in methanol and alkaline water. From their physico-chemical properties, these antibiotics are presumed to be acyloctapeptides containing a lactone linkage, and their differences occur in amino acid and fatty acid residues. The antibiotics are active against Gram-positive bacteria in vitro and in vivo.

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. A lactone linkage was suggested to reside between L-threo-beta-hydroxyaspartic acid and 3-hydroxy-fatty acid residues by degradation experiments. The amino acid sequences of plusbacins A2 and B2 were confirmed by Edman degradation of their deacylated products, and supported by mass spectrometric studies. From the above, structures of all components of plusbacins were concluded.

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. The IR spectra indicated these to be peptides. Molecular formulas C28H46N4O6, C27H44N4O6 and C26H42N4O6 for cepafungins I, II and III were indicated by elemental analysis and SI-MS. Cepafungins exhibited inhibitory activity against yeast and fungi, and antitumor activity against P388 leukemia in mice.

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. Different fatty acyl groups connected to the N-terminus of the threonine distinguish the three cepafungins. The major component I and minor component III are new substance, but the minor component II has a structure identical with that of the recently reported antibiotic glidobactin A.

Isolation and characterization of hypeptin from Pseudomonas sp.

An antibiotic, named hypeptin, was isolated from the culture broth of a strain of Pseudomonas sp. The antibiotic was extracted with butanol and purified by chromatography on a Sephadex LH-20 column. The antibiotic is basic in nature. The dihydrochloride is soluble in aqueous alcohols and positive to ninhydrin and Sakaguchi's reaction. A molecular formula, C44H71N13O15.2HCl was indicated by microanalysis and secondary ion MS. The IR spectrum and acid hydrolysis indicated it to be a peptide antibiotic. The stereochemistries of the amino acids produced by hydrolysis were clarified by HPLC using a chiral column. The antibiotic is active in vitro against a wide variety of anaerobic bacteria and aerobic Gram-positive bacteria.

Isolation of CB-25-I, an antifungal antibiotic, from Serratia plymuthica.

A new antifungal antibiotic, CB-25-I, was isolated from the culture broth of a strain of Serratia plymuthica. The antibiotic, a water-soluble dipeptide, is structurally related to Sch 37137 and A 19009, both produced by strains of Actinomycetales. The antibiotic exhibits inhibitory activity against Candida albicans in YNB medium (a synthetic medium), but the activity is significantly reduced in Sabouroud dextrose medium.

Isolation and characterization of new antibiotics resorcinomycins A and B.

New antibiotics, resorcinomycins A and B, were isolated from the culture broth of a streptomycete strain identified as Streptoverticillium roseoverticillatum. The antibiotics are water-soluble amphoteric substances, positive to SAKAGUCHI'S reagent. The molecular formulas C14H20N4O5 and C13H18N4O5 for A and B were indicated by elemental analysis and secondary ion MS. The structures of these antibiotics were determined by 1H and 13C NMR spectrometry and some chemical evidences to be N-[(S)-alpha-guanidino-3,5-dihydroxy-4-isopropylphenylacetyl]glyci ne and N-[(S)-alpha-guanidino-3,5-dihydroxy-4-ethylphenylacetyl]-glycine, respectively.

Isolation and characterization of katanosins A and B.

Two peptide antibiotics katanosins A and B were isolated from the culture broth of a strain related to the genus Cytophaga. These antibiotics are basic peptides soluble in aqueous alcohols. The molecular formulae C57H95N15O17 for A and C58H97N15O17 for B were indicated. The constituent amino acids of katanosin A are suggested to be Thr (1), Ser (1), Val (1), Leu (3), Arg (1) and three unusual amino acids. In katanosin B, the Val residue is replaced by Ile. Katanosins A and B are active against Gram-positive bacteria in vitro and in vivo.

The structures of katanosins A and B.

1H and 13C NMR studies on katanosin A confirmed the presence of eight usual amino acid residues which were previously deduced by amino acid analysis and suggested the presence of beta-hydroxyaspartic acid, beta-hydroxyleucine and beta-phenylserine residues. These amino acids were isolated and confirmed, including their stereochemistries, by comparison with the respective authentic specimens. Stereochemistries of the usual amino acids were determined by comparing the L-leucylated amino acids with reference compounds by HPLC. Lithium borohydride reduction and chromic acid oxidation of katanosin A and alkali-treated katanosin A elucidated a lactone linkage between the C-terminal Ser and phenylserine residues. Edman degradation on alkali-treated katanosin A clarified the total amino acid sequence. The difference in katanosins A and B was determined to be replacement of Val in A by Ile in B. Thus, the structures of katanosins A and B were elucidated.

PB-5266 A, B and C, new monobactams. I. Taxonomy, fermentation and isolation.

New monobactams, PB-5266 A, B and C were isolated from the culture filtrate of Cytophaga johnsonae PB-5266 by various types of column chromatography and preparative reverse phase HPLC. PB-5266 A, B and C exhibited weak antibacterial activity against a sensitive mutant of Escherichia coli to beta-lactam antibiotics.

PB-5266 A, B and C, new monobactams. II. Physico-chemical properties and chemical structures.

The chemical structures of three new monobactams, PB-5266 A, B and C, were elucidated by their physico-chemical properties and spectrometric studies. In contrast to previously described monobactams, they all possess a dehydroasparagine residue.

Isolation of L-cycloserine from Erwinia uredovora.

An antibiotic which seems to be a cell wall synthesis-inhibitor was isolated from a bacteria strain identified as Erwinia uredovora. The antibiotic was identified with L-cycloserine from its physico-chemical properties. This is the first example for isolation of L-cycloserine as a microbial product.

Production of N-acetylisopenicillin N and isopenicillin N from Streptomyces tokunonensis sp. nov.

N-Acetylisopenicillin N was isolated from the culture broth of Streptomyces tokunonensis sp. nov., and identified from 1H NMR spectroscopy and release of L-alpha-aminoadipic acid by acid hydrolysis. In the course of this study, the specimen of penicillin N isolated from this strain was proved to contain a small amount of isopenicillin N by HPLC.

Asparenomycins A, B and C, new carbapenem antibiotics. II. Isolation and chemical characterization.

New carbapenem antibiotics named asparenomycins A, B and C were isolated from the fermentation broths of Streptomyces tokumonensis sp. nov. and of Streptomyces argenteolus. The fermentative production, isolation and physico-chemical properties of these antibiotics are described.

Isolation of N-(2,6-diamino-6-hydroxymethylpimelyl)-L-alanine from Micromonospora chalcea.

A novel dipeptide, N-(2,6-diamino-6-hydroxymethylpimelyl)-L-alanine, was isolated from the culture broth of a microorganism identified as Micromonospora chalcea. The dipeptide exhibits antimicrobial activity against Escherichia coli on a synthetic medium, and the activity is synergistically enhanced by several cell wall synthesis-inhibitors.

The structures of tridecaptins B and C (studies on antibiotics from the genus Bacillus. XXV).

On examining the structures of the antibiotics tridecaptins B and C, the constituent amino acids were separated and their chiralities were determined. The constituent fatty acids were identified by gas chromatography and mass spectrometry. Cleavage with N-bromosuccinimide and sequential analysis by EDMAN degradation demonstrates the sequence of the C-terminal side of tridecaptins B and C. Deacylation with polymyxin acylase of tridecaptin B and successive EDMAN degradation revealed the sequence of the N-terminal side of tridecaptin B. Finally partial acid hydrolysis on tridecaptin C clarified the sequence of the N-terminal side of tridecaptin C.

Isolation of tridecaptins A, B and C (studies on antibiotics from the genus Bacillus. XXIII).

Three new antibiotics, tridecaptins A, B and C, were isolated from culture broths of strains of Bacillus polymyxa AR-110, B-2 and E-23, respectively. All are acyl tridecapeptides differing from each other in the fatty acid components and amino acid residues. They are weakly active against Gram-negative and Gram-positive bacteria in vitro and in vivo.