ABSTRACT
BACKGROUND: Tellurium is a rare metalloid that exerts high toxicity on cells, especially on bacteria, partly due to reactive oxygen species (ROS) generation. Moreover, it has also been observed that tellurite can target free cell thiols groups (RSH) (i.e. reduced glutathione (GSH)), enhancing the cellular redox imbalance. Additionally, in vitro experiments have suggested that several enzymes can reduce tellurite (IV) to its elemental form (0); where RSH present on their active sites may be responsible for the process. Nevertheless, the mechanisms implemented by bacteria for tellurite reduction and its role in resistance have not been evaluated in vivo. RESULTS: This work shows that tellurite reduction to elemental tellurium is increased under anaerobic conditions in E. coli cells. The in vivo tellurite reduction is related to the intracellular concentration of total RSH, in the presence and absence of oxygen. This metabolization of tellurite directly contributes to the resistance of the bacteria to the oxyanion. CONCLUSIONS: We demonstrated that in vivo tellurite reduction is related to the intracellular thiol concentration, i.e. large availability of cellular RSH groups, results in a more significant reduction of tellurite. Furthermore, we observed that, when the bacterium exhibits less resistance to the oxyanion, a decreased tellurite reduction was seen, affecting the growth fitness. Together, these results let us propose that tellurite reduction and the intracellular RSH content are related to the oxyanion bacterial resistance, this tripartite mechanism in an oxygen independent anaerobic process.
Subject(s)
Tellurium , Escherichia coli , Oxidation-Reduction , AnaerobiosisABSTRACT
La endometriosis apendicular tiene una frecuencia menor de 1 por ciento de las endometriosis pelvicas. Su diagnostico en la mayor parte de las ocasiones es incidental. Se informa un caso de endometriosis apendicular en una mujer en la cuarta decada de la vida, con antecedentes de esterilidad primaria, que ingreso con cuadro doloroso abdominal en cuadrante inferior derecho sin otros datos clinicos, radiologicos e do laboratorio que sugirieran el diagnostico. Se intervino con diagnostico preoperatorio de apendicitis aguda y se el realizo apendicectomia. El estudio histopatologico demostro focos endometrioides en la serosa apendicular sin datos de apendicitis aguda. La endometriosis debe considerarse entre las posibilidades diagnosticas en mujeres con cuadros "apendiculares" en los dias premenstruales y menstruales