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Behavioral response of resistant and sensitive
Pseudomonas aeruginosa S22 isolated from Sohag
Governorate, Egypt to cadmium stress
El-Sayed, M. Soltan1,
Rehab, M. Mohamed1 and Ahmed, A. Shoreit2*
1Sohag
University, Faculty of Science, Botany Department, Egypt.
2Assiut University, Faculty of Science, Botany
Department, Egypt.
*Corresponding author. E-mail:
ashoreit@yahoo.com.
Fax: +2 088 2342708.
Accepted
21 March, 2008 |
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A total of
62 Pseudomonas isolates were selected from a
contaminated site at Sohag district and tested for their
resistance tto 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.
Key words:
Pseudomonas aeruginosa, cadmium stress, heavy metal
resistance. |
