Effect of a highly concentrated lipopeptide extract of Bacillus subtilis on fungal and bacterial cells

Author(s)

Etchegaray, Augusto ^[1] ; Bueno, Carolina de Castro ^[1] ; de Melo, Itamar Soares ^[2] ; Tsai, Siu Mui ^[3] ; Fiore, Marli de Fatima ^[3] ; Silva-Stenico, Maria Estela ^[3] ; Beraldo de Moraes, Luiz Alberto ^[4] ; Teschke, Omar ^[5]

Affiliation

^[1] Pontificia Univ Catolica Campinas, Fac Quim, BR-13012970 Campinas, SP - Brazil

^[2] Embrapa Meio Ambiente, Microbiol Lab, Jaguariuna, SP - Brazil

^[3] Univ Sao Paulo, CENA, BR-13400970 Piracicaba, SP - Brazil

^[4] Univ Sao Paulo, Dept Quim, BR-14100000 Ribeirao Preto, SP - Brazil

^[5] Univ Estadual Campinas, Lab Nanoestruct & Interfaces, Inst Fis, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: Archives of Microbiology; v. 190, n. 6, p. 611-622, DEC 2008.
• Web of Science Citations: 34

Abstract

Lipopeptides produced by Bacillus subtilis are known for their high antifungal activity. The aim of this paper is to show that at high concentration they can damage the surface ultra-structure of bacterial cells. A lipopeptide extract containing iturin and surfactin (5 mg mL-1) was prepared after isolation from B. subtilis (strain OG) by solid phase extraction. Analysis by atomic force microscope (AFM) showed that upon evaporation, lipopeptides form large aggregates (0.1-0.2 mu m2) on the substrates silicon and mica. When the same solution is incubated with fungi and bacteria and the system is allowed to evaporate, dramatic changes are observed on the cells. AFM micrographs show disintegration of the hyphae of Phomopsis phaseoli and the cell walls of Xanthomonas campestris and X. axonopodis. Collapses to fungal and bacterial cells may be a result of formation of pores triggered by micelles and lamellar structures, which are formed above the critical micelar concentration of lipopeptides. As observed for P. phaseoli, the process involves binding, solubilization, and formation of novel structures in which cell wall components are solubilized within lipopeptide vesicles. This is the first report presenting evidences that vesicles of uncharged and negatively charged lipopeptides can alter the morphology of gram-negative bacteria. (AU)

• FAPESP's process: 03/12529-4 - Nanotechnology: manufacture of nanostructures and supramolecular structures in liquid medium: observation of structures formed and investigation of processes of formation of nanostructures
• Grantee: Omar Teschke
• Support Opportunities: Research Projects - Thematic Grants