Keywords : coli

Isolation of tRNA From Uropathogenic Escherichia Coli

Ibtesam Ghadban Auda Al-Grawi

Iraqi Postgraduate Medical Journal, 2008, Volume 7, Issue 2, Pages 178-181

Transfer RNA is a type of RNA which during protein synthesis Act as an adaptor molecule ,matching amino acids to their codons on mRNA . tRNA also functions in the formation of cross links during peptidoglycan synthesis.
The aim of this study is that, extraction of tRNA from uropathogenic Escherichia coli then detect the presence of such molecules after extraction and measure the purity of the tRNA extract solutions.
Thirty uropathogenic E.coli isolates were isolated from hospitalized and non hospitalized patients, complaining of urinary tract infections, of Al-Kadhymia Teaching Hospital and subjected to tRNA extraction. A method of tRNA extraction was modified by adding sodium dodecyl sulfate (SDS)instead of urea. Polyacrylamide gel electrophoresis and two methods of staining ,ethidium bromide staining and silver staining ,as well as spectrophotometric detection were used.
Ethidium bromide stained gel reveals bands with molecular weight less than yeast rRNA .Silver stained gel shows bands with molecular weight less than ova albumin(45000 dalton ) but with approximate molecular weight of chymotrpsinogen(24000 dalton).
The tRNA extracts were relatively pure with the modified method of extraction. In the present study, a modification of polyacrylamide gel electrophoresis to detect tRNA and to determine their molecular weigh was applied.

The Location of Aerobactin Determinants of Uropathogenic E. coli in Association with Hemolysin Production Antibiotic Resistance and Patient Characteristics.

Ibtesam Ghadban Auda

Iraqi Postgraduate Medical Journal, 2006, Volume 5, Issue 2, Pages 223-229

Aerobactin, Hemolysin and the resistance to some antibiotics axe important Features of
Uropathogenic E. coli (UPEC). The characteristics of patients from which we isolate the
UPEC have associate with these Features and their determinants location.
We determined the phenotypic expression and gene location of Aerobactin and phenotypic
expression of Hemolysin among 60 UPEC isolates. We correlated the presence of Aerobactin system
with antibacterial agents resistance. The expression of Hemolysin and the characteristics of patients.
Two methods of plasmid curin, sodium dodecyl sulfate and elevated temperature plasmid curing, are
used then plasmid extraction and agarose gel electrophoresis are performed to determine the
location of Aerobactin determinants and the size of Aerobactin plasmids, as well as the location of
the determinants of some antibiotics resistance which were ampicillin (Am), Tetracycline (Tc),
gentamicin (GM), Chloramphenicol (C) and co- trimazole (Co).
Aerobactin and hemolysin expression among UPEC isolates were 93.3% and 35% respectively. The
isolates of non compromised patients produce statistically higher rate of expressed hemolysin (90.5%
, p<0.01). Plasmid- borne Aerobactin was absent in UPEC isolates of non compromised patients
(89.5%, p<0.01). On the contrary compromised patient isolates express plasmid Aerobactin of 59.5%
(p<0.02). We also found that Aerobactin determinants are located on a plasmid in compromised
patient isolates and associated with the absence of chromosomal Hemolysin production (82.9%,
p<0.01). Yet, The chromosomal aerobactin is associated with hemolysin production (61.9%,
p<0.02). Furthermore, UPEC isolates of compromised patients carry relatively large plasmid of
Aerobactin (85.7%. p<0.05) and these large plasmids carry either chloramphenicol (83.3%.p<0.02) or
gentamicin determinants (100%. P<0.01) but not co- trimazole, tetracycline or ampicillin.
The isolates of non compromised patients carry chromosomal Aerobactin and hemolysin. While the
isolates of compromised patients express plasmid Aerobactin and do not express chromosomal
hemolysin. Aeobactin plasmids are relatively large plasmids and carry either chloramphenicol or
gentamicin resistance determinants.