Behavioral response of resistant and sensitive Pseudomonas aeruginosa S22 isolated from Sohag Governorate, Egypt to cadmium stress

A total of 62 Pseudomonas isolates were selected from a contaminated site at Sohag district and tested for their resistance to cadmium metal. Isolate no. 22 was found to be the most resistant one and has a plasmid with molecular wt 27.491 Kbp. The minimal inhibition concentrations (MIC) for the resistant (R) and adopted sensitive (S) isolates were 1.0 and 0.119 mmol L-1, respectively. The growth, protein content and maximum specific growth rate (k) decreased with increasing concentrations of heavy metal. The generation time (T) increased with the addition of divalent cations (Fe2+, Mg2+ and Ca2+) plus cadmium. Under cadmium stress, three proteins of high molecular weights (208, 78 and 33.5 KD) were lost while one protein with low molecular weight (2.5 KD) was induced. LPS profile was modified under stress of CdCl2. Absence of bands in region I, which represents the O-specific antigen, and region II (core-oligosaccharide linked to lipid A) were recorded at high concentrations of CdCl2.