Effect of Cu(II) and Cr(VI) on oxidative stress actinomycete strains isolated from polluted area

L.B. VILLEGAS; M. J. AMOROSO; C. M. ABATE

Mar del Plata

Congreso; XLIII Reunión Anual. SAIB; 2007

The organisms growing in aerobic conditions are continuously exposed to reactive oxygen species (ROS) formed as by-products during normal cellular metabolism.  These forms of oxygen are highly damaging towards cellular constituents, including DNA, lipids and proteins.  These molecules are detoxified via superoxide dismutases (SODs) and catalases (CAT).  Both enzymes create the first and the most important line of antioxidant defense. The objective of the present work is to study the Cu(II) or Cr(VI) effect on the SOD and CAT activities in actinomycetes strain. Amycolaptosis ABO and Streptomyces MC1, isolated from contaminated sediments by heavy metals were used.  Cells were incubated in Minimal Medium (MM) containing glucose as only carbon source and supplemented with 10 and 20 ppm of Cu(II) or Cr(VI) during 72 h at 30 ºC and 200 rpm. Cells were harvested at 24, 48 and 72 h. SOD activity cell extracts in native polyacrylamide gel electrophoresis (PAGE) was detected by its ability to deplete superoxide, which can reduce nitroblue tetrazolium.  The catalase activity was measured spectrophotometicaly at room temperature following the decrease of absorption at 240 nm.  High heavy metal concentrations enhanced the total SOD and CAT activities from both strains and these increased with incubation time.  Amycolaptosis ABO presented two bands with SOD activity and Streptomyces MC1 presented a single band.  One of the band from Amycolaptosis ABO and the only band from Streptomyces MC1 were inhibited with H2O2.  Then they were corresponding to FeZnSOD. The other band from Amycolaptosis ABO were not inhibited with H2O2 or NaN3.