No abstract

Inactivation of enveloped viruses (VSy S¥V, and SHV-1) by surfactin lipopeptides was dependent on the hydrophobicity, i.e. the number of carbon atoms of the fatty acid, and on the charge of the peptide moiety as well as on the virus species. Surfactins with fatty acid chains of 13 carbon atoms showed very low antiviral activity in comparison to C14 and C15 isoforms. C15 surfactin monomethyl ester also inactivated SFVwhich was resistant to the mixture of surfactin isoforms as produced by Bacillus subtilis. In contrast, the dimethyl ester showed no virus-inactivation capacity. Disintegration of viral structures as determined by electron microscopy after inactivation of VSVand SFVwas comparable to the liter reduction. The effect of the surfactin isoforms and methyl esters on erythrocyte hemolysis correlated with the virus-inactivation capacity. Surfactins with a fatty acid chain moiety of 15 carbon atoms and one negative charge showed the highest antiviral activity.Bioactive peptides with diverse structures and biological activities have been isolated from various microorganisms.1>2) Bacillus subtilis, a soil bacterium, produces nonribosomally the cyclic lipopeptide antibiotic surfactin2) showing biosurfactant,3?4) antimicrobial,5'6^antimycoplasmatic,7)antiviral,8~10) antitumor1 1} and hemolytic3' 5) properties. Surfactin consists of an anionic seven-memberedpeptideand a hydrophobic /J-hydroxy fatty acid varying in length and branching of its carbon chain (for a review of these isoforms see ref. 12). The fatty acid is bound via its carboxyl group to the TV-terminal glutamic acid and the lipopeptide ring is closed by lactone formation between the /?-hydroxy group of the fatty acid and the carboxyl group of the C-terminal leucine. The numberof carbon atoms of its /J-hydroxy fatty acid varies from 13 to 15; the main lipid component is 3-hydroxy-1 3-methylmyristic acid. 13'14)Several authors8^10) have shown antiviral properties of surfactin, especially against enveloped viruses.10) All these studies have been performed with the natural mixture of Togaviridae, a model virus for the hepatitis G virus).