Authors: S.J. Chaves, P. Zuniga, J.S. Chaves
Affilation: Instituto Tecnologico de Costa Rica, Costa Rica
Pages: 377 - 380
Keywords: SWNTs, toxicity, microorganisms, mechanism, siderophores
In this study we described that iron-sequestering molecules are responsible for the toxicity of iron containing SWNTs to microorganisms. After incubating different concentrations of functionalized SWNTs with bacteria and fungal cells, it was found that these microorganisms produced siderophores. These molecules were seen in the medium as early as 10 min after the addition of SWNTs. After 30 min we observed some bacterial and fungal cells saturated with siderophore-containing SWNTs. Analysis of the bacterial and fungal cells saturated with siderophore-containing SWNTs revealed that those bacterial cells were dead because too many SWNTs present in the bacterial cells interfered with processes such as binary fission, and electron transport. Contact with the SWNTs is not a possible mechanism in this case since the microorganisms had enough time to produce siderophores and still thrived for a few minutes after the endocytosis of the siderophores. In addition, we noticed that the effect of siderophore-containing SWNTs in plants had the opposite effect. Instead of dying, the plants were able to grow better. This work provides more insight on the toxicity effects of SWNTs in different organisms and the potential use of SWNTs as a new method to treat bacterial and fungal diseases.
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