title: Differential oxidative stress responses in castor semilooper, Achaea janata.
abstract: Balance between reactive oxygen species (ROS) and the antioxidant (AO) defense mechanisms is vital for organism survival. Insects serve as an ideal model to elucidate oxidative stress responses as they are prone to different kinds of stress during their life cycle. The present study demonstrates the modulation of AO enzyme gene expression in the insect pest, Achaea janata (castor semilooper), when subjected to different oxidative stress stimuli. Antioxidant enzymes' (catalase (Cat), superoxide dismutase (Sod), glutathione-S-transferase (GST) and glutathione peroxidase (Gpx)) partial coding sequences were cloned and characterized from larval whole body. Tissue expression studies reveal a unique pattern of AO genes in the larval tissues with maximum expression in the gut and fat body. Ontogeny profile depicts differential expression pattern through the larval developmental stages for each AO gene studied. Using quantitative RT-PCR, the expression pattern of these genes was monitored during sugar-induced (d-galactose feeding), infection-induced (Gram positive, Gram negative and non-pathogenic bacteria) and pesticide-induced oxidative stress (Bt Cry toxin). d-Galactose feeding differentially modulates the expression of AO genes in the larval gut and fat body. Immune challenge with Escherichia coli induces robust upregulation of AO genes when compared to Bacillus coagulans and Bacillus cereus in the larval fat body and gut. Cry toxin feeding predominantly induced GST upregulation in the gut. The current study suggests that though there are multiple ways of generation of oxidative stress in the insect, the organism tailors its response by insult- and tissue-specific recruitment of the antioxidant players and their differential regulation for each inducer.
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: Ayinampudi
authors.initials: A
authors.lastname: Pavani
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Chaitanya
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Chauhan
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: Anwesha
authors.initials: A
authors.lastname: Dasgupta
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India. Electronic address: apdgsl@uohyd.ernet.in.
authors.forename: Aparna
authors.initials: A
authors.lastname: Dutta-Gupta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000276:immunology; D005786:Gene Expression Regulation; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D009036:Moths / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase
keywords: Antioxidants; Insect immunity; Integrated pest management; Oxidative stress