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Biomedical subjects

F Besson

Publications and source records attributed to F Besson.

At least 37 records · Page 2Linked to original sources
PubMed1987

Isolation and characterization of new iturins: iturin D and iturin E.

Two new antibiotics, iturin D and iturin E, were isolated from a strain of Bacillus subtilis producing iturin A. These compounds belong to the iturin group, the acid hydrolysates contained alpha-amino acids Asp3, Glu1, Pro1, Ser1, Tyr1, and a mixture of n-C14, iso-C15, anteiso-C15, iso-C16 and n-C16 beta-amino acids. They differ from iturin A by the presence of a free carboxyl group in iturin D and a carboxymethyl group in iturin E.

Antifungal Agents↗
PubMed1986

Effect of various growth conditions on spore formation and bacillomycin L production in Bacillus subtilis.

Bacillomycin L is produced by Bacillus subtilis NCIB 8872 in the stationary phase; it is excreted into the culture medium, without prior accumulation in the bacterial cells. The production of bacillomycin L is largely dependent on the composition of the culture medium. The action of specific inhibitors of sporulation, netropsin and diethyl malonate, on antibiotic synthesis is dependent on the composition of the culture medium. Although they occurred at the same time, there appears to be no direct correlation between sporulation and antibiotic synthesis.

Bacillus subtilis↗
PubMed1979

Interactions between bacterial membranes and peptidolipids: lysis of micrococcus luteus protoplasts by derivatives of peptidolipidic antibiotics from bacillus subtilis.

The lysis of protoplasts of Micrococcus luteus has been tested with various derivatives of three peptidolipidic antibiotics: iturin A, mycosubtilin and bacillomycin L. The lytic activity is dependent to the nature of the substituting group and to the position of the substituted aminoacid residue. The acetylation of OH groups leads to a decrease of the lytic activity of the natural antibiotics. The methylation of aspartyl residues of bacillomycin L gives a strong lytic activity while natural bacillomycin L has no lytic activity. The methylation of the tyrosyl residue enhances the lytic activities of iturin A and of bacillomycin L-dimethyl ester and reduces that of mycosubtilin. Correlations between the structures of derivatives and their lytic action on M. luteus protoplasts are discussed.

Anti-Bacterial Agents↗
PubMed1979

Preparation and antibacterial activity upon Micrococcus luteus of derivatives of iturin A, mycosubtilin and bacillomycin L, antibiotics from Bacillus subtilis.

Methylated and acetylated derivatives of iturin A and mycosubtilin and methylated derivatives of bacillomycin L were prepared and their antibacterial activity on Micrococcus luteus was compared with the activity of the original substance. the results obtained show the importance of polar groups for the antibiotic activity of the substances of iturin group.

Anti-Bacterial Agents↗
PubMed1979

Antifungal activity upon Saccharomyces cerevisiae of iturin A, mycosubtilin, bacillomycin L and of their derivatives; inhibition of this antifungal activity by lipid antagonists.

The antifungal activity of three antibiotics of the iturin group: iturin A, mycosubtilin, bacillomycin L and of eleven methylated and acetylated derivatives of these antibiotics was tested upon Saccharomyces cerevisiae. The lowest MIC values were found for natural antibiotics. The substitution of polar groups diminished the antifungal activity. Various lipids, sterols, fatty acids, fatty acid methyl esters and phospholipids were tested as inhibitors of the antifungal activity of iturin A, mycosubtilin and bacillomycin L. Cholesterol was the strongest inhibitor upon the three antibiotics; ergosterol, oleic acid and cis-vaccenic acid were less potent inhibitors. Among phospholipids, phosphatidyl choline inhibited bacillomycin L and iturin A while diphosphatidyl glycerol inhibited bacillomycin L and mycosubtilin. The inhibitory effect appeared to be dependent on the nature of both the hydrophilic group and the fatty acid part of phospholipids.

Antifungal Agents↗
PubMed1978

Identification of antibiotics of iturin group in various strains of Bacillus subtilis.

Thirty eight strains of B. subtilis were tested for the presence of antifungal antibiotics of the iturin group. The characterization of these antibiotics was made on the basis of: antifungal activity against P. chrysogenum, isolation and purification of the active substance, quantitative analysis of alpha-aminoacids and identification of the liposoluble dipeptide obtained by partial hydrolysis. The only antibiotics of the iturin group found were: iturin A, mycosubtilin and bacillomycin L.

Antifungal Agents↗
PubMed1977

[The structure of bacillomycin L, an antibiotic from Bacillus subtilis (author's transl)].

The structure of bacillomycin L, an antifungal agent isolated from the culture medium of a strain of Bacillus subtilis, has been investigated. The peptide moiety contains one mole each of D-aspartic acid, L-aspartic acid, L-glutamine, L-serine, D-serine, L-threonine, and D-tyrosine. The lipid moiety is a mixture of 3-amino-12-methyltridecanoic acid (46%), 3-amino-12-methyltetradecanoic acid (38%, 3-amino-14-methylpentadecanoic acid (11%), and two minor homologues. The peptide sequence and the cyclic structure were determined by structural analysis of the peptides obtained by mild acid hydrolysis. The molecular weight was determined by the thermoosmotic method; this showed that bacillomycin L has a monomeric structure which is given in Formula 1.

Amino Acid Sequence↗
PubMed1976

Characterization of iturin A in antibiotics from various strains of Bacillus subtilis.

Iturin A, an antifungal lipopeptide characterized by the presence of homologous liposoluble beta-aminoacids was found to be the active component to bacillomycin B, bacillomycin R and eumycin. Iturin A was identified by thin-layer chromatography, aminoacid analysis and by characterization of liposoluble aminoacids and peptides. Another two preparations: the antibiotic of Raubitschek and the bacillomycin of Landy et al. contain components of the same structural type but they are different from iturin A.

Amino Acids↗