%0 Journal Article
%T IMPACT OF DIFFERENT ENVIRONMENTAL PARAMETERS UPON THE SUSCEPTIBILITY TO HEAVY METALS SALTS IN ESCHERICHIA COLI AQUATIC STRAINS
%A Emilia Panus
%A Mariana Carmen Chifiriuc
%A Coralia Bleotu
%A Magda Mitache
%J Letters in Applied NanoBioScience
%D 2012
%I Comporter SRL
%X Purpose: to investigate the relationships among the expression of susceptibility to heavy metal salts, different incubation temperatures and chemical composition of the culture media in E. coli aquatic strains. 100 strains of E. coli isolated from Black Sea were investigated for the expression of resistance to different bivalent metals (Cu, Co, Mn, Zn, Ni) compounds. The experiments were performed comparatively at different incubation temperatures (22ˇăC, 37ˇăC and 44ˇăC) in aerobic and anaerobic conditions, NaCl concentrations (from 0 to 10%), glucose (1.5 and 3%) and pH (5.0, 7.2 and 9.6). The metals susceptibility patterns varied with the tested parameter and the bivalent metal compounds. The temperature growth induced an increase in susceptibility of the tested strains to Zn (from 85% at 22ˇăC, 20% at 37ˇăC and 100% at 44ˇăC), Mn (from 50% at 22ˇăC, 15% at 37ˇăC and 75% at 44ˇăC), Cu (from 10% at 22ˇăC, 0% at 37ˇăC and 55% at 44ˇăC), Co (from 10% at 22ˇăC, 0% at 37ˇăC and 30% at 44ˇăC), Ni (from 0% at 22ˇăC, 0% at 37ˇăC and 5% at 44ˇăC). Concerning the influence of salinity, the highest 10% NaCl induced to occurrence of susceptibility to all tested metals, followed by 2, 6 and 7% NaCl with susceptibility to 4 of 5 metals. The highest susceptibility levels to Zn and Mn was expressed in inverse order to 3, 4, 6, 7, 0, 2 and 0.5 % NaCl, while to Cu at 3, 2 and 7% NaCl. The tested strains were very resistant to Ni and Co, at the majority of tested salinities. Concerning the relationship between the chemical composition of the culture medium and the susceptibility levels to metals, the higher glucose concentration of 3% and the alkaline pH induced higher rates of susceptibility Mn, Zn and Ni. In conclusion the expression of heavy metals susceptibility features of the E. coli strains is strongly influenced by the incubation temperature and salinity, demonstrating the role of these parameters in the selection of resistance genes in the aquatic strains.
%K Heavy metals salts
%K Esherichia coli
%K aquatic strains
%K divalent transitional metal salts
%U http://nanobioletters.com/wp-content/uploads/downloads/2012/06/10.LIANBS.Panus_.pdf