Defensive responses in Capsicum annuum (L) plants, induced due to the feeding by different larval instars of Spodoptera litura (F (original) (raw)
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Biochemical defence of pro-oxidant plant allelochemicals by herbivorous insects
Biochemical Systematics and Ecology, 1992
A new aspect of interactions among insect herbivores and defensive chemistry of plants in the regulation of oxygen toxicity exerted by pro-oxidant allelochemicals is described. Endogenous oxygen toxicity results from activation of the ground state of molecular oxygen to the superoxide anion radical (O 2.-), hydrogen peroxide (H202), hydroxyl radical (.OH), lipid hydroperoxides (LOOHs), and peroxyl radicals (LO 2 • or RO 2 .). The strongly lipid-peroxidizing singlet oxygen (~AgO 2) is also produced during light activation of photosensitizers. Ingestion of pro-oxidants exacerbates oxygen toxicity by increasing the production of these deleterious forms of oxygen. The role of ascorbate, u.-tocopherol, glutathione, carotenoids and urate as antioxidants in insects is apparent, but needs more work for the elucidation of their roles. The major defence mechanism includes a group of antioxidant enzymes represented by superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase's peroxidative activity (GSTPX), glutathione reductase (GR), and DT-diaphorase. SOD converts O2.-radicals to H202 and 02, CAT decomposes H202 to H20 and 02, GSTPX reduces LOOHs to LOHs with GSH as reductant, and GSSG formed from GSH during the GSTPX reaction is reduced to GSH by GR. DT-diaphorase is an important antioxidant in that it reduces quinones by a two-electron reduction to stable products, thereby preventing the one-electron reduction to semiquinone radicals which generate O2.-radicals. Therefore, these enzymes are crucial for insect herbivores for preventing the free-radical cascade of oxygen, and terminating the toxic lipid peroxidation chain reaction, in response to the endogenous and potential exogenous oxidant-induced injury.
Archives of Insect Biochemistry and Physiology, 2006
Allelochemicals play important roles in the plant defense against herbivorous insects. They act as feeding deterrents, interfere with digestion and nutrient absorption, and cause production of potentially dangerous oxidative radicals. This study demonstrates that the distributions of oxidative radicals and of the antioxidant enzymes that eliminate them are compartmentalized in the digestive tract of Spodoptera littoralis larvae. Feeding on diets supplemented with the tannic acid (TA), a-solanine, and demissidine, respectively, did not affect the rate of food passage through the digestive tract of larvae but 1.25, 2.5, and 5%
Mechanisms for regulating oxygen toxicity in phytophagous insects
Free Radical Biology and Medicine, 1990
The antioxidant enzymatic defense of insects for the regulation of oxygen toxicity was investigated. Insect species examined were lepidopterous larvae of the cabbage looper (Trichoplusia nil southern armyworm (Spodoptera eridania), and black swallowtail (Papilio polyxenes). These phytophagous species are subject to both endogenous and exogenous sources of oxidative stress from toxic oxygen radicals, hydrogen peroxide (H_,O2) and lipid peroxides (LOOH). In general, the constitutive levels of the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GT), and its peroxidase activity (GTp0, and glutathione reductase (GR), correlate well with natural feeding habits of these insects and their relative susceptibility to prooxidant plant allelochemicals, quercetin (a flavonoid), and xanthotoxin (a photoactive furanocoumarin). Induction of SOD activity which rapidly destroys superoxide radicals, appears to be the main response to dietary prooxidant exposure. A unique observation includes high constitutive activity of CAT and a broader subcellular distribution in all three insects than observed in most mammalian species. These attributes of CAT appear to be important in the prevention of excessive accumulation of cytotoxic H202. Unlike mammalian species, insects possess very low levels of a GPOX-like activity toward H20_~. Irrefutable proof that this activity is due to a selenium-dependent GPOX found in mammals, is lacking at this time. However, the activity of selenium-independent GTox is unusually high in insects, suggesting that GTpx and not GPOX plays a prominent role in scavenging deleterious LOOHs. The GSSG generated from the GPOX and GTp~ reactions may be reduced to GSH by GR activity. A key role of SOD in protecting insects from prooxidant toxicity was evident when its inhibition resulted in enhanced toxicity towards prooxidants. The role of antioxidant compounds in protecting these insects from toxic forms of oxygen has not been explored in depth. A major finding, however, is that these insects are lutein accumulators. Lutein is a dihydroxy (diol) derivative of [?,-carotene, and it is a good quencher of activated forms of oxygen and free radicals. Levels of lutein are highest in P. polyxenes which specializes in feeding on prooxidant-containing plants.
Antioxidant enzyme activities in the southern armyworm, Spodoptera eridania
Comparative Biochemistry and Physiology Part C: Comparative Pharmacology, 1988
No acute 24 hr toxicity was observed with mid-5th instar larvae of the southern armyworm, Spodoprera eridaniu, exposed to the prooxidant allelochemicals, xanthotoxin and quercetin. Decreased RGR values for the xanthotoxin treated larvae suggest the beginning of toxicity. 2. Superoxide dismutase and catalase activity is very high in these insects, suggesting that these enzymes may be part of a secondary defense system against prooxidant insult and may account for their tolerance of prooxidant allelochemicals such as quercetin, which are ingested accidentally but frequently due to S. eridania's wide breadth of diet. 3. There is no glutathione peroxidase activity in these insects although they do have glutathione reductase activity.
Allelopathy Journal
Herbivore damage induces several chemical changes in the infested plants which are normally considered as plant's defense responses. We studied the effects of tobacco cutworm [Spodoptera litura (Fabricius)] feeding on primary, secondary metabolites and enzymatic constituents in leaves of sweet potato (Ipomoea batata L) plants. Quantitative and qualitative changes in biochemical and enzymatic profile of infested plants were analyzed spectrophotometrically and compared with normal intact plants. The individual phenolic acids were identified using high performance liquid chromatography (HPLC) by comparing with standard phenolic compounds in accordance to retention times. The quantities of proteins, amino acids and total phenol content in infested plants were enhanced, whereas, carbohydrate concentration was decreased than normal plants. An increase in the activities of peroxidase (POD), phenyl alanine ammonia lyase (PAL), super oxide dismutase (SOD) and a decrease in the levels of ...
Italian Journal of Zoology, 2015
The non-mulberry silkworm, Antheraea mylitta Drury, 1773, is important for the silk industry. Its larvae are phytophagous and pass through five stages (1st-5th instar) during larval development. Cellular events during their development contribute to increased levels of pro-oxidants. Antioxidant defences are, therefore, of critical importance in minimising oxidative damage. Thus, in the present study, stage-specific oxidative challenges and relative levels of antioxidant defences have been assessed during the larval development of A. mylitta. The overall results indicate a progressive decrease in oxidative threat during larval ontogeny. Comparatively high activity of superoxide dismutase (SOD) and catalase (CAT) observed in the 1st instar larvae indicates an adaptive antioxidant response, which could attenuate the elevated oxidative challenges. CAT activity remained unaltered in the midgut during transformation of the larvae from 4th-5th instar, and it was below detection level in serum. Glutathione S-transferase (GST) activity did not exhibit a specific trend; however, it showed tissue specificity in advanced larvae. Glutathione (GSH) content was progressively enhanced during development and exhibited a compensatory function with ascorbic acid (ASA), thus substantiating the role of a GSH-ASA redox couple. Findings of the study imply that early larvae (1st-3rd instar) encounter considerable degrees of pro-oxidative assault and get protection from enzymatic antioxidants. In contrast, advanced larvae receive combined protection from enzymatic and nonenzymatic antioxidants. Therefore, it is assumed that oxidative stress during larval development of A. mylitta is stage-specific and, accordingly, the antioxidant defences are strategic in providing protection to the developing larvae.
Archives of Biological Sciences
The European corn borer (Ostrinia nubilalis) is one of the most important insect pests of maize, and has a significant impact on the production of this crop. In this work, we examined the effects of different insecticides on the antioxidative defense system of O. nubilalis larvae. The experimental setup consisted of a completely randomized block design with 4 replicates. Four experimental groups were formed as follows: control (C), indoxacarb (250 mL ha-1), chlorantraniliprole (100 mL ha-1) and the chlorantraniliprole+lambda cyhalothrin (200 mL ha-1) group. Larvae from maize stems were collected 20 days after insecticide application and the whole larvae were homogenized. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST), and the total amount of free SH groups were assessed. Comparison of the experimental groups showed that indoxacarb significantly affected the activities of GST, ...
Effect of Host Plants on Biochemical Markers of Oxidative Stress within Tissues of Pea Aphid
Journal of Plant Protection Research, 2012
The effect of some species of the Fabaceae family (the pea Pisum sativum L., broad bean Vicia faba L. and vetch V. sativa L.) on biochemical markers of oxidative stress within tissues of the pea aphid, Acyrthosiphon pisum Harris (Homoptera, Aphididae), has been studied. The highest concentration of superoxide anion radical (O 2 ─ ), hydrogen peroxide (H 2 O 2 ) and lipid peroxidation products thiobarbituric acid reactive substances (TBARS) was recorded for morphs that fed on the broad bean. The opposite tendency was observed for the level of total thiols, that were the highest for insects reared on the pea. Among the studied aphid morphs, the highest concentration of superoxide anion and hydrogen peroxide was noted for the wingless females whereas TBARS content was the highest within the winged migrant tissues. Different results were obtained for the total thiols, where apterae as well as migrants reared on the tested plants, had comparable content of these compounds. Our experiments indicate that oxidative stress may play an important role in interactions between the pea aphid and their host plants.
Biochemical markers of oxidative stress within tissues of cereal aphids
Acta Biologica Hungarica, 2009
Effects of some dietary o-dihydroxyphenols on biochemical markers of oxidative stress within tissues of Sitobion avenae (Fabricius), (Homoptera, Aphididae) and Rhopalosiphum padi (Linnaeus), (Homoptera, Aphididae) has been studied. Among the studied aphid morphs the highest concentration of total thiols, hydrogen peroxide and lipid peroxidation products (TBARS) was noted for winged adults (alatae). Higher content of H 2 O 2 was observed within tissues of the oligophagous species R. padi while the monophagous species S. avenae had higher TBARS and total thiols concentration. Aphids exposed the dietary pro-oxidative o-dihydroxyphenols (quercetin, caffeic acid, chlorogenic acid) demonstrated significantly lower concentration of total sulfhydryls and higher level of TBARS and H 2 O 2 than the control ones. Among the studied compounds, chlorogenic acid showed the strongest effect on the level of thiols and TBARS while caffeic acid caused the highest accumulation of the hydrogen peroxide within the aphid tissues.
Annals of the Entomological Society of America, 2015
Dichlorvos (DDVP; 2,2-dichlorovinyl dimethyl phosphate) is an organophosphate insecticide widely used in the control of pests. This study aims to determine the changes caused by DDVP in the antioxidant enzyme activity, lipid peroxidation level, and ion content of a model organism, Galleria mellonella L. (Lepidoptera: Pyralidae). Larvae of G. mellonella were fed sublethal concentrations of DDVP (2, 4, 6, and 8 mg/100 g feed). Exposure to DDVP resulted in induction of superoxide dismutase and catalase activities, and lipid peroxidation in larvae. Potassium and sodium ion levels were significantly altered by DDVP exposure. These results suggest that DDVP causes oxidative stress and lipid peroxidation and alters the antioxidant enzyme activities and ion balance in G. mellonella larvae. Additionally, these results indicate that G. mellonella is a useful model for testing the effects of insecticides.