We have been involved in the exploration of bacterial responses to oxidative stress since 1990, when we realized their role in antibiotic resistance and virulence. Several papers, book chapters, abstracts in local congresses and theses on the soxRS-mediated response to superoxide radicals in Escherichia coli, have been published. Most of this work has been carried out by Ana Fuentes. We have described how different agents can modulate the soxRS response --mercury and the lack of iron, for instance, can activate the soxRS system, while some antioxidants can inhibit it. Javier Diaz, using his expertise on sequence-analysis software, found similarities between some of the regulatory proteins involved.

Since 1995, we have also been exploring the effects of ozone on bacteria --work that began as the undergraduate thesis work of Veronica Leautaud, now a graduate student at the Harvard School of Public Health. The preliminary results obtained by Veronica helped us earn a Fogarty International Research Collaborative Award from the NIH, with Bruce Demple at Harvard University as principal investigator. The award supported work conducted by Gabriela Jimenez demonstrating that ozone, at concentrations similar to those found in the atmosphere of polluted cities such as Mexico City, could affect bacteria and cause a gradual increase in antibiotic resistance and virulence. Initial results have been published.

As part of an educational effort sponsored by Roche and aimed at the medical community, we have developed awareness programs on the role of antioxidants in medicine. We have organized several conferences and interviews across Mexico, and in 1998 Carlos Amabile and Ana Fuentes published a short book (in Spanish) on the subject.