TY - JOUR
T1 - Identification of an atypical form of 30 kDa SOD - A possible virulence factor in clinical isolates of Shigella spp
AU - Prakash, Radhakrishnan
AU - Devaraj, Halagowder
AU - Devaraj, S. Niranjali
N1 - Funding Information:
We thank Dr. Philippe J. Sansonetti for providing strain M90T and Head of the Department of Medical Microbiology Sri Ramachandra Medical College and Research Institute (SRMC &RI) Porur, India, for clinical strains of Shigella flexneri and Shigella boydii. The financial support given by UGC (New Delhi) is acknowledged.
PY - 2004/12
Y1 - 2004/12
N2 - Reviews on the pathogenic mechanisms of Shigella species show a lacunae in the understanding of the bacterial antioxidant defense system and its regulations. This study was done to investigate the regulation of expression of antioxidant enzymes in clinical isolates of Shigella species, under various growth conditions. The in vitro expression of superoxide dismutase in the clinical isolates of Shigella spp., is modulated by both endogenous and exogenous factors. During aerobic and iron repleted growth conditions, the expression of the MnSOD and FeSOD enzymes were higher, and an atypical SOD was also expressed. However, under anaerobic growth conditions and in plasmid-cured strains, the antioxidant enzyme activities were decreased and the atypical SOD was not expressed. Absence of the atypical form of SOD may be due to the low oxygen environment. Plasmid-encoded factors may also play a role in the expression of this SOD, which had a molecular weight of ∼30 kDa. In the rat ileal loop ligation assay, mild lesions were observed only in the intestinal microvilli of rats injected with plasmid-cured strains of Shigella spp., suggesting that plasmid-encoded factors, including those that regulate the expression of the atypical SOD, are essential for the virulence of Shigella spp.
AB - Reviews on the pathogenic mechanisms of Shigella species show a lacunae in the understanding of the bacterial antioxidant defense system and its regulations. This study was done to investigate the regulation of expression of antioxidant enzymes in clinical isolates of Shigella species, under various growth conditions. The in vitro expression of superoxide dismutase in the clinical isolates of Shigella spp., is modulated by both endogenous and exogenous factors. During aerobic and iron repleted growth conditions, the expression of the MnSOD and FeSOD enzymes were higher, and an atypical SOD was also expressed. However, under anaerobic growth conditions and in plasmid-cured strains, the antioxidant enzyme activities were decreased and the atypical SOD was not expressed. Absence of the atypical form of SOD may be due to the low oxygen environment. Plasmid-encoded factors may also play a role in the expression of this SOD, which had a molecular weight of ∼30 kDa. In the rat ileal loop ligation assay, mild lesions were observed only in the intestinal microvilli of rats injected with plasmid-cured strains of Shigella spp., suggesting that plasmid-encoded factors, including those that regulate the expression of the atypical SOD, are essential for the virulence of Shigella spp.
KW - Antioxidant enzymes
KW - Iron supplementation
KW - Plasmid curing
KW - Shigella spp.
KW - Superoxide dismutase (SOD)
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U2 - 10.1023/B:MCBI.0000049369.78195.b1
DO - 10.1023/B:MCBI.0000049369.78195.b1
M3 - Review article
C2 - 15663190
AN - SCOPUS:9444226489
SN - 0300-8177
VL - 267
SP - 91
EP - 98
JO - Molecular and cellular biochemistry
JF - Molecular and cellular biochemistry
IS - 1-2
ER -