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  • 1
    Electronic Resource
    Electronic Resource
    Activities of enzymes that detoxify superoxide anion and related toxic oxyradicals in Trichoplusia ni (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 6 (1987), S. 85-96 
    Details
    ISSN: 0739-4462
    Keywords: cabbage looper ; catalase ; glutathione peroxidase ; glutathione reductase ; superoxide dismutase ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In third-, fourth-, and fifth-instar larvae of the cabbage looper moth, Trichoplusia ni, the activities of the antioxidant enzymes, superoxide dismutase (SOD*), catalase (CAT), glutathione peroxidase (GPOX), and glutathione reductase (GR) were examined using 850 g supernatants of whole-body homogenates. The enzyme activities, expressed as units mg-1 protein min-1 at 25°C ranged as follows: SOD, 0.67-2.13 units; CAT, 180.5-307.5 units; GPOX, none detectable; and GR, 0.40-1.19 units. There was a similar pattern of changes for SOD and CAT activities with larval ontogeny, but not for GR. The cabbage looper apparently uses SOD and CAT to form a “defensive team” effective against endogenously produced superoxide anion (O2≿). Glutathione may serve as an antioxidant for the destruction of any organic/lipid peroxides formed, and GSH oxidized to glutathione disulfide would be recycled by GR. Bioassays against pro-oxidant compounds exogenous sources of (O2≿) show high sensitivity of mid-fifth instars to the linear furanocoumarin, 8-methoxypsoralen (xanthotoxin) primarily from photoactivation (320-380 nm), and auto-oxidation of the flavonoid, quercetin. The LC50s are 0.0004 and 0.0045% (w/w) concentration of xanthotoxin and quercetin, respectively. Both pro-oxidants have multiple target sites for lethal action and, in this context, the role of antioxidant enzymes is discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940060203
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  • 2
    Electronic Resource
    Electronic Resource
    Subcellular distribution and activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the southern armyworm, Spodoptera eridania (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 7 (1988), S. 173-186 
    Details
    ISSN: 0739-4462
    Keywords: antioxidant enzymes ; catalase ; detoxification of oxyradicals ; glutathione peroxidase ; glutathione reductase ; superoxide dismutase ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In mid-fifth-instar larvae of the southern armyworm, Spodoptera eridania, the subcellular distribution of four antioxidant enzymes - superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPOX), and glutathione reductase (GR) - were examined. Two-thirds (4.26 units ·mg protein-1) of the SOD activity was found in the cytosol, and one-thirds (2.13 units ·mg protein-1) in the mitochondria. CAT activity was unusually high and not restricted to the microsomal fraction where peroxisomes are usually isolated. The activity was distributed as follows: cytosol (163 units) mitochondria (125 units) and microsomes (119 units). Similar to CAT, the subcellular compartmentalization of both GPOX and GR was unusual. No activity was detected in the cytosol, but in mitochondria and microsomes, GR levels were 5.49 and 3.09 units. Although GPOX activity exhibited 14-16-fold enrichment in mitochondria and microsomes, respectively, over the 850g crude homogenate, the level was negligible (mitochondria = 1.4 × 10-3 units; microsomes = 1.6 × 10-3 units), indicating that this enzyme is absent. The unusual distribution of CAT has apparently evolved as an evolutionary answer to the absence of GR from the cytosol, and the lack of GPOX activity.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940070304
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  • 3
    Electronic Resource
    Electronic Resource
    Antioxidant enzymes of the black swallowtail butterfly, Papilio polyxenes, and their response to the prooxidant allelochemical, quercetin (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 8 (1988), S. 101-112 
    Details
    ISSN: 0739-4462
    Keywords: superoxide dismutase ; catalase ; glutathione reductase ; glutathione peroxidase ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The black swallowtail butterfly larvae, Papilio polyxenes, are specialist feeders that have adapted to feeding on plants containing high levels of prooxidant allelochemicals. Third, fourth, and fifth instar larvae were tested for their antioxidant enzyme activities, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPOX), using 850-g supernatants from whole-body homogenates. The overall antioxidant enzyme profile for P. polyxenes was high compared to other insects, with activities ranging as follows: SOD, 1.1-7.5; CAT, 124-343; GR, 1.0-7.5; and GPOX, 0 units.To determine whether these antioxidant enzymes were inducible, P. poly xenes larvae were given a prooxidant challenge by dipping parsley leaves (their diet in the initial studies) in solutions of quercetin, such that the leaves became coated with this prooxidant flavonoid. Mid-fifth instar larvae fed on quercetin-coated leaves were assayed for antioxidant enzyme activities as was previously done with the larvae fed the standard diet. Food consumption and quercetin intake were monitored. SOD activity was increased almost twofold at the highest quercetin concentration tested. CAT and GR activity, on the other hand, were inhibited by increased quercetin consumption, with GR activity completely inhibited at the highest quercetin concentration after 12 h of feeding. GPOX activity, not present in control insects, was also not inducible by a quercetin challenge. These studies point out the key role that the antioxidant enzymes play in insect defenses against plant prooxidants.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940080204
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