Catalase activity and innate immune response of Caenorhabditis elegans against the heavy metal toxin lead.

Balasubramanian Vigneshkumar, Shunmugiah Karutha Pandian, Krishnaswamy Balamurugan

Department of Biotechnology, Alagappa University, Karaikudi, Tamil Nadu-630003, India.

Environmental toxicology 2013 Jun

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The heavy metal lead-induced oxidative stress on Caenorhabditis elegans was examined at the level of catalase activity and on innate immunity. Stress-induced C. elegans was exposed to Pseudomonas aeruginosa PA14::GFP for monitoring the impact at the physiological level. Role of catalase on the innate-immune responses of C. elegans was examined. PA14::GFP did not colonize lead pretreated C. elegans intestinal cells significantly compared to untreated controls, indicating stress-mediated upregulation of host-immunity. Semiquantitative PCR analyses of lead-exposed and PA14-infected C. elegans mRNA showed significant upregulation of candidate antimicrobial enzyme gene lys-7 after 24 h of exposures. Upregulation of metallothionein(mtl-1) when compared to mtl-2 in response to the lead suggesting active detoxification of metal by mtl-1. Exogenously provided Catalase (0.4-3.2 U) induced significant upregulation of lys-7 compared to controls. lys-7 upregulation during lead exposure was reconfirmed by real-time PCR. Confocal microscopy and fluorescence spectrophotometer analyses indicated that the lead pretreated C. elegans was significantly less colonized by PA14::GFP when compared to controls. Relative expression of ctl-1 and ctl-2 mRNA was measured using real time PCR and found to be regulated during lead exposures. Over all, the upregulation of antimicrobial gene expression appears to be correlated with the level of catalase during stress emphasizing their key roles in defensive mechanism(s). These results provide a link between the stress and related immune responses which can be explored in higher systems. Copyright © 2011 Wiley Periodicals, Inc.

Citation

Balasubramanian Vigneshkumar, Shunmugiah Karutha Pandian, Krishnaswamy Balamurugan. Catalase activity and innate immune response of Caenorhabditis elegans against the heavy metal toxin lead. Environmental toxicology. 2013 Jun;28(6):313-21