Comparative study of the influence of melatonin and vitamin E on the surface characteristics of Escherichia coli.

AIMS: Melatonin is a hormone produced by the pineal gland and that affects the response of various cell membranes to an oxidative stimulus.

METHODS AND

RESULTS

The present study evaluates the hydrophobic characteristics of Escherichia coli in response to melatonin (100 nmol l(-1), 200 micromol l(-1)) and to vitamin E (5 mg dl(-1)). A reduction was found in the surface hydrophobicity of E. coli at concentrations of 200 micromol l(-1) melatonin in a Müeller-Hinton (MH) broth. These effects were modified when a protein synthesis inhibitor (chloramphenicol) was added at sub-lethal concentrations to the broth. Vitamin E produced a greater diminution in surface hydrophobicity than melatonin. The adherence of E. coli to nitrocellulose filters increased in the presence of melatonin + chloramphenicol, and vitamin E. The effects observed were independent of the concentration of iron in the broth.

CONCLUSION

Oxidative stress plays an important role in modifying the surface characteristics of E. coli, which could affect the micro-organism's capacity to adhere to epithelia.

SIGNIFICANCE AND IMPACT OF THE STUDY: We think that the oxide reduction potential of the host may be a determinant factor in the bacterial colonization of animal tissue.