Subtilosin A, a new antibiotic peptide produced by Bacillus subtilis 168: isolation, structural analysis, and biogenesis

Subtilosin A, a new antibiotic produced by Bacillus subtilis 168, was extracted from culture medium with n-butanol and purified to homogeneity by a combination of gel filtration and thin-layer chromatography. The yield was 5.5 mg from a liter of culture. It had bacteriocidal activity against some gram-positive bacteria. Amino acid analysis and mass spectrometry showed that it was a peptide with a molecular weight of 3398.9, consisting of 32 usual amino acid and some non-amino acid residues. Its amino- and carboxyl-termini were blocked. By analysis of the fragments obtained by partial acid hydrolysis, as well as by chymotryptic and thermolysin digestions of reduced and S-carboxymethylated samples and Achromobacter protease I digestion of performic acid-oxidized samples, the amino acid sequence was determined to be as follows: X-Gly-Leu-Gly-Leu-Trp-Gly-Asn-Lys-Gly-Cys-Ala-Thr-Cys-Ser-(sequence; see text) Ile-Gly-Ala-Ala-Cys-Leu-Val-Asp-Gly-Pro-Ile-Pro-Asp-Glx-Ile-Ala-Gly-Ala. The analyses of cross-linking structures revealed that there were linkages between the amino- and carboxyl-termini and between the Cys-19 and the Glx-28 residues through an unknown residue with a residue weight of 163. Consequently, subtilosin A was deduced to be a cyclic peptide antibiotic with a novel cross-linking structure. The production of subtilosin A begins at the end of vegetative growth and finishes before spore formation. Studies on the correlation between the production of subtilosin A and spore formation with decoyinine in the original strain and in asporogenous mutants of B. subtilis 168 suggested that there was no close correlation between the two phenomena. The production of subtilosin A was repressed by inhibitors of protein and RNA synthesis in contrast to that of many other antibiotic peptides, suggesting that it is synthesized by the mechanism of usual protein synthesis.     

Purification and characterization of a new peptide antibiotic produced by a thermotolerant Bacillus licheniformis strain

A Bacillus licheniformis strain, 189, isolated from a hot spring environment in the Azores, Portugal, strongly inhibited growth of Gram-positive bacteria. It produced a peptide antibiotic at 50 degrees C. The antibiotic was purified and biochemically characterized. It was highly resistant to several proteolytic enzymes. Additionally, it retained its antimicrobial activity after incubation at pH values between 3.5 and 8; it was thermostable, retaining about 85% and 20% of its activity after 6 h at 50 degrees C and 100 degrees C, respectively. Its molecular mass determined by mass spectrometry was 3249.7 Da.     

HA-1-92, A new antifungal antibiotic produced by Streptomyces CDRIL-312: Fermentation,isolation, purification and biological activity

A new antifungal antibiotic, HA-1-92, was isolated from the biomass of Streptomyces CDRIL-312, by extracting in butanol and further purified by silica gel column chromatography followed by preparative TLC. The antibiotic is presumed to be an oxohexaene macrolide and showed promising antifungal activity against yeasts and filamentous fungi including human and plant pathogens. It was found to be less toxic in mice than known oxohexaenes.     

Fermentation and isolation of epidermin,a lanthionine containing polypeptide antibiotic from Staphylococcus epidermidis

Summary Staphylococcus epidermidis TÜ 3298/DSM 3095 produces epidermin, a basic 21-residue peptide-amide antibiotic active against aerobic and anaerobic Gram-positive bacteria. Fermentations were performed by batch and feeding processes up to the 2001 scale. Highest yields were obtained when the first purification step was integrated into the fermentation process by on-line adsorption of the antibiotic. Isolation and purification by adsorption chromatography and ion exchange chromatography were performed batchwise.     

HP17, a new pigment-like antibiotic produced by a new strain of Spirillospora

Spirillospora strain 719 produces several antibiotics. On solid and liquid media, a deep red pigment is formed and diffuses throughout the culture. It was extracted with methanol from the mycelium cake and from the fermentation broth after precipitation at pH 2 and purified using TLC and HPLC. Its u.v. absorption spectrum and its physicochemical characteristics place this antibiotic in the 3.3.2.2.8 of the Berdy et al. classification. In most respects, it resembles proteinaceous pigment from Spirillospora 1655 and 1309-b that was studied and named spirillomycin. However, HP17 differs from spirillomycin principally in molecular weight and chemical nature.     

Fermentation, isolation, and biological activity of maduramycin: a new antibiotic from Actinomadura rubra.

In a continuing search for new antibiotics, the species Actinomadura rubra (Sveshnikova et al.) J. Meyer et M. Sveshnikova 1974 (strain IMET 13001) was found to produce a red pigment with indicator properties, designated maduramycin. The pigment (C28H22O10; m.w. 518 m/e-; m.p. 305--310 degrees C (dec.); UVmax 225.307 nm) possesses a strong antimicrobial activity against gram-positive bacteria, including strains which produce inactivating enzymes for some commercial antibiotics. Maduramycin forms a complex with serum albumin, but no complex formation with DNA was observed using absorption spectroscopic and polarographic methods. Maduramycin additionally inhibits the action of some enzymes. The LC50 of maduramycin in mice was greater than 250 mg/kg on intraperitoneal administration. Fermentation, isolation, and some of the chemical and biological properties of this new antibiotic are described.     

AH7, a non-polyenic antifungal antibiotic produced by a new strain of Streptosporangium roseum

An antibiotic (AH7) produced by Streptosporangium roseum strain 214 was investigated. This compound was extracted with chloroform from the filtrate culture and purified using thin-layer chromatography and high pressure liquid chromatography procedures. The antibiotic strongly inhibited the growth of several strains of fungi and bacteria known to be plant and human pathogens. This compound differed from all other antibiotics known to be synthesized by Streptosporangium spp. Some of its chemical and physical properties resembled those of maytansines produced by Nocardia but the antibiotic AH7 has only antibacterial and antitumoral activities.     

H107, a new aminoglycoside anti-Pseudomonas antibiotic produced by a new strain of Spirillospora

Spirillospora spp. (strain 719) has been the source of several antibiotics. One of these designated H107 is produced as a trace. Compared with other antibiotics produced by the same strain, it was obtained only from the broth filtrate after precipitation with acetic acid followed by extraction with n-butanol. It was a water soluble metabolite active against Gram-negative bacteria and especially Pseudomonas spp., and was identified as an aminoglycoside compound. This is the first report of aminoglycoside anti-Pseudomonas production by Spirillospora.     

HM17, a new polyene antifungal antibiotic produced by a new strain of Spirillospora

H. HACÈNE, K. KEBIR, D. SID OTHMANE AND G. LEFEBVRE. 1994. An antifungal antibiotic (HM17) was obtained from a new isolate classified to the genus Spirillospora on the basis of its chemical and morphological properties. On solid media this antibiotic strongly inhibited the growth of strians of Fusarium oxysporum formae speciales albedinis, Botrytis cinerea, Gaeumaniomyces graminis and several other fungi known to be plant and human pathogens. Antifungal activity in culture collection strains of Spirillospora has not so far been reported. The u.v. absorption spectrum and physico-chemical characteristics place HM17 in the methylpentaene sub-group of polyene macrolides. HM17 is different from other known methylpentaenes. This is the first report of polyene production by a Spirillospora.     

Study of nisin, a polypeptide antibiotic produced by a culture of Streptococcus lactis, strain MSU

The drug nisin produced by the lactic acid bacteria S. lactis, strain MSU, was identified and described. After 18-hour cultivation of the strain the fermentation broth was centrifuged. The centrifugate contained at an average 2000 IU/ml of the antibiotic. It was purified on silica gel C-3, the eluate was lyophilized and the dry substance was studied by disk electrophoresis in 20 per cent PAAG in the presence of sodium dodecylsulfate. It was found that S. lactis, strain MSU, produced a polypeptide component of the molecular weight of 7000 D. Its electrophoretic mobility corresponded to that of nisaplin. Therefore, nisin was shown to be identical to nisaplin.     

Characterization of a novel phenazine antibiotic gene cluster in Erwinia herbicola Eh1087

Erwinia herbicola strain Eh1087 produces the broad-spectrum phenazine antibiotic D-alanylgriseoluteic acid (AGA). In this report, a cluster of 16 ehp (Erwinia herbicola phenazine) plasmid genes required for the production of AGA by Eh1087 is described. The extent of the gene cluster was revealed by the isolation of 82 different Eh1087 AGA- mutants, all found to possess single mini-Tn5lacZ2 insertions within a 14 kbp DNA region. Additional transposon insertions that did not affect antibiotic production by Eh1087 were created to define the boundaries of the gene cluster. The size and location of genes between these boundaries were derived from a combination of DNA sequence analyses, minicell protein analyses and the correlation between mutation position and the production of coloured AGA intermediates by many ehp mutants. Precursor-feeding and complementation experiments resulted in 15 ehp genes being assigned to one of four functional groups according to their role in the synthesis of AGA. Group 1 is required for the synthesis of the phenazine nucleus in the form of antibiotic precursor one (AP1, phenazine-1,6-dicarboxylic acid). Group 2 is responsible for conversion of AP1 to AP2, which is subsequently modified to AP3 (griseoluteic acid) and exported by the group 3 gene products. Group 4 catalyses the addition of D-alanine to AP3 to create AGA, independently of groups 1, 2 and 3. A gene that is divergently transcribed from the 15 AGA synthesis ehp genes confers resistance to AGA.     

Frequency and diversity of antibiotic production by putative Erwinia herbicola strains

The frequency and diversity of antibiotic production by putative Erwinia herbicola strains were investigated. Of 346 putative Erw. herbicola strains isolated from plants in various regions of France, 42% produced antibiotics on a glycerol-ammonium medium that were inhibitory to Erw. amylovora , the fire-blight pathogen. Of the 90 strains studied in detail that produced antibiotics, 84 produced types of antibiotics that were not toxic to Erw. amylovora (strain CFBP3051) in the presence of different amino acids. On the basis of the amino acids that inhibited the toxicity of the antibiotics to CFBP3051, the 90 strains could be divided into 13 different groups. It is suggested that the effectiveness of an antibiotic in inhibiting Erw. amylovora in vivo may depend on the free amino acid composition of the plant.