The effects of boric acid-induced oxidative stress on antioxidant enzymes and survivorship in Galleria mellonella

Larvae of the wax moth, Galleria mellonella (L.), were reared from first instar on a diet supplemented with 156, 620, 1,250, or 2,500 ppm boric acid (BA). The content of malondialdehyde (MDA, an oxidative stress indicator), and activities of the antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPx)] were determined in the fat body and hemolymph in the 7th instar larvae and newly emerged pupae. Relative to control larvae, MDA was significantly increased in larval hemolymph, larval and pupal fat body, but decreased in the pupal hemolymph. Insects reared on diets with 156- and 620-ppm BA doses yielded increased SOD activity but 1,250- and 2,500-ppm doses resulted in decreased SOD activity in larval hemolymph. SOD activity was significantly increased but CAT was decreased in the larval fat body. High dietary BA treatments led to significantly decreased GST activity. However, they increased GPx activity in larval hemolymph. Dietary BA also affected larval survival. The 1,250- and 2,500-ppm concentrations led to significantly increased larval and pupal mortality and prolonged development. In contrast, the lowest BA concentration increased longevity and shortened development. We infer that BA toxicity is related, at least in part, to oxidative stress management.     

Longevity ofBracon brevicornis [Hym: Braconidae] adults as influenced by nourishment on artificial and natural foods

Laboratory trials were undertaken to investigate the nutrition ofBracon brevicornis Wesmael adults on: (1) artificial diets (sucrose, treacle, honey bee and tap water); (2)Sesamia larvae (exposed under 3 manipulations); (3) 5 host species (Galleria, Ephestia, Sesamia, Spodoptera andOstrinia); in addition to starvation at 12, 15, 20, 25, 30, 35 and 40°C. Among artificial diets, honey bee solution was the most suitable that prolonged significantly each sex to be more than 1 month at 25°C.A Bracon female supplied daily with a freshSesamia-larva was significantly longer-lived than when kept with the “unchanged”Sesamia-larva. Larvae of borers (Sesamia andOstrinia), gave significantly the highest longevity for females among other host species. Adult-longevity was significantly decreased with an increase in temperature. Females were significantly longer-lived than males when kept only with living host insects. However, such sex difference was generally uncertain when either was supplied with an artificial diet or starved under temperatures ranging from 12–40°C.     

Antioxidant defense in mitochondria during diapause and postdiapause development of European corn borer (Ostrinia nubilalis, Hubn.)

Antioxidant enzymes (CAT, catalase; GPx, selenium nondependent glutathione peroxidase; GST, glutathione-S-transferase; GR, glutathione reductase; DHAR, dehydroascorbate reductase) were determined in the mitochondria of diapausing and non-diapausing larvae and pupae of both diapausing and non-diapausing larvae of the European corn borer (Ostrinia nubilalis, Hubn., Lepidoptera: Pyralidae). CAT, GST, and DHAR activity in mitochondria of diapausing larvae were reduced compared to non-diapausing larvae. Pupae of diapaused-larvae possessed lower GST, but higher DHAR activities compared to pupae of non-diapaused individuals. Comparison between larvae and pupae revealed lower GPx activity in the mitochondria of pupae. CAT activity in the mitochondria of pupae was higher compared to diapausing larvae, but lower than in non-diapausing ones. Correlation and canonical discriminant analyses revealed different antioxidant enzyme compositions for a particular stage and developmental pattern. Our results show that antioxidant enzymes have a similar role in the regulation of energetics in mitochondria as that in diapause and metamorphosis.     

The protective effect of melatonin against cypermethrin-induced oxidative stress damage in Spodoptera litura (Lepidoptera: Noctuidae)

Antioxidant enzymes form the first-line defense against free radicals damage in organisms. Their regulation depends mainly on the oxidant and antioxidant status of the cell, given that oxidants are their principal modulators. Therefore, the aim of the present study was to investigate the effect of melatonin on synthetic pyrethroid insecticide-induced antioxidative enzymes activity in Spodoptera litura larvae. In addition, activities of enzymatic antioxidants viz. superoxide dismutase (SOD), glutathione S-transferase (GST), catalase (CAT), glutathione reductase (GR), α, β-esterase, and acetylcholine esterase (AChE) were assessed. There was no significant change in GST levels in the melatonin-treated groups. Melatonin modulates cypermethrin-induced changes in the activities of esterase and AChE, whereas SOD, CAT, and GR activity was significantly increased in melatonin-treated samples when compared to control. In conclusion, the results of the current study revealed that SP toxicity activated oxidant systems in all antioxidant systems in some tissues of insects. Melatonin administration led to a marked increase in antioxidant activity and inhibited GST and AChE in most of the tissues studied.     

Oxidative Damage Induced by Arsenic in Mice or Rats: A Systematic Review and Meta-Analysis

In this meta-analysis, studies reporting arsenic-induced oxidative damage in mouse models were systematically evaluated to provide a scientific understanding of oxidative stress mechanisms associated with arsenic poisoning. Fifty-eight relevant peer-reviewed publications were identified through exhaustive database searching. Oxidative stress indexes assessed included superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), glutathione-s-transferase (GST), glutathione reductase (GR), oxidized glutathione (GSSG), malondialdehyde (MDA), and reactive oxygen species (ROS). Our meta-analysis showed that arsenic exposure generally suppressed measured levels of the antioxidants, SOD, CAT, GSH, GPx, GST, and GR, but increased levels of the oxidants, GSSG, MDA, and ROS. Arsenic valence was important and GR and MDA levels increased to a significantly (P < 0.05) greater extent upon exposure to As³⁺ than to As⁵⁺. Other factors that contributed to a greater overall oxidative effect from arsenic exposure included intervention time, intervention method, dosage, age of animals, and the sample source from which the indexes were estimated. Our meta-analysis effectively summarized a wide range of studies and detected a positive relationship between arsenic exposure and oxidative damage. These data provide a scientific basis for the prevention and treatment of arsenic poisoning.     

Activity of glutathione S‐transferase and esterase enzymes in Helicoverpa armigera (Hübner) after exposure to entomopathogenic fungi

Helicoverpa armigera, a polyphagous insect of crops and vegetables, is acquiring resistance against many commercial insecticides. The present study shows variations in the activity of two detoxification enzymes, namely esterase and glutathione S‐transferase (GST), in H. armigera after exposure to different isolates of entomopathogenic fungi. After treatment of larvae with the different isolates (Day 0), samples were collected on three days (Days 3, 5 and 7) for enzyme analysis. High GST activity was found in samples of hemolymph, intestine and fat bodies of H. armigera following treatment with Beauveria bassiana (isolate Bb‐08), Metarhizium anisopliae (isolates Ma‐11.1 and Ma‐4.1), and Isaria fumosorosea (isolates If‐02 and If‐2.3). High esterase activity was recorded in samples of the intestine and fat bodies on various days after treatment, whereas increased esterase activity in hemolymph was noted only in samples from Day 5 after treatment with M. anisopliae (Ma‐4.1). The detection of high GST and esterase activity demonstrates the possibility of the development of resistance against these microbial control agents in H. armigera.     

Comparison of the cold hardiness of two larval Lepidoptera (Noctuidae)

Abstract Diapause larvae of the European corn borer (Ostrinia nubilalis (Hubn.)) and the related Mediterranean noctuid Sesamia cretica Led. possess sufficient supercooling ability to avoid freezing over their normal environmental temperature ranges. In progressive chilling experiments (10 days acclimation at each 5° step in the temperature range from 15 to ?5°C), mean supercooling points (measured at a cooling rate of 0.1°C min^?1) were lowered from ?20.4°C at 15°C to ?24.0°C at 5°C (lower lethal temperatures: c.?28°C) in O.nubilalis, compared with ?15.0 to ?17.2°C (lower lethal temperatures: ?15 to ?17°C respectively) in S.cretica. Concentrations of glycerol and trehalose determined by gas chromatography of whole body extracts were consistently higher in the former than in the latter species at both 15 and 5°C, and may be responsible for the deeper supercooling in O.nubilalis larvae. Acclimation to 5°C increased glycerol levels in O. nubilalis extracts compared with 15°C, and this was enhanced in larvae exposed for a further 10 days at each of 0 and ?5°C (glycerol being 438μmol ml^?1 body water). Haemolymph glycerol concentrations showed a similar pattern to whole body extracts in this species. Fat body glycogen was reduced during low temperature acclimation in both species. Body water contents did not change with acclimation in O.nubilalis, whilst S.cretica, containing significantly more water, lost c.7% during acclimation from 15 to 5°C. Haemolymph osmolalities increased during acclimation, especially in Ostrinia larvae, probably as a result of the accumulation of cryoprotectants. The majority of O.nubilalis larvae survived freezing under the conditions of the cooling experiments, whilst larvae of S.cretica did not, thereby confirming an element of freezing tolerance in the former.     

Responses of the antioxidative and biotransformation enzymes in the aquatic fungus <Emphasis Type="Italic">Mucor hiemalis</Emphasis> exposed to cyanotoxins

Objectives

To investigate antioxidative and biotransformation enzyme responses in Mucor hiemalis towards cyanotoxins considering its use in mycoremediation applications.

Results

Catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx) in M. hiemalis maintained their activities at all tested microcystin-LR (MC-LR) exposure concentrations. Cytosolic glutathione S-transferase (GST) activity decreased with exposure to 100 µg MC-LR l^?1 while microsomal GST remained constant. Cylindrospermopsin (CYN) at 100 µg l^?1 led to an increase in CAT activity and inhibition of GR, as well as to a concentration-dependent GPx inhibition. Microsomal GST was inhibited at all concentrations tested. β-N-methylamino-l-alanine (BMAA) inhibited GR activity in a concentration-dependent manner, however, CAT, GPx, and GST remained unaffected.

Conclusions

M. hiemalis showed enhanced oxidative stress tolerance and intact biotransformation enzyme activity towards MC-LR and BMAA in comparison to CYN, confirming its applicability in bioreactor technology in terms of viability and survival in their presence.

     

The use of biomarkers in the antioxidant responses of Daphnia magna to the acute and chronic exposure to no. 20 diesel oil and 2,4-dichlorophenol

Abstract

The effects of no. 20 diesel oil exposure, 2,4-dichlorophenol (2,4-DCP) exposure and combined exposure on the antioxidant defences of Daphnia magna have been studied systematically for the first time. Daphnia magna was exposed for 1 day or 10 days to several concentrations of 0, 0.005, 0.01, 0.05, 0.1, 0.5 or 1.0 mg L^?1 solutions. Antioxidant defences consisting of the levels of reduced glutathione (GSH) and glutathione disulfide (GSSG) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), selenium dependent glutathione peroxidase (Se-GPx) and glutathione S-transferase (GST) of daphnids were determined to evaluate their protective roles and to analyse the occurrence of oxidative stress. The possible antioxidant defence mechanisms are discussed. Furthermore, GST can be a potential biomarker and an early-warning index for the pollutants in waters in that GST responded sensitively to 1 day and 10 days of exposure to diesel oil and 2,4-DCP and 10 days of combined exposure. Crossover comparisons showed an antagonistic action about the no-observed-effect concentration (NOEC) against Daphnia magna, which needs further studies.     

Resistance selection with cadmium and changes in the activities of antioxidases in Boettcherisca peregrina (Diptera: Sarcophagidae)

In order to establish a physiological link between antioxidases and the resistance level of insects to cadmium (Cd), natural populations of Boettcherisca peregrina (Diptera: Sarcophagidae) were maintained for 20 generations and reared either on an uncontaminated diet or on a diet contaminated with cadmium (Cd) at a concentration equivalent to the median lethal concentration (LC₅₀) as determined every five generations. A relatively susceptible strain (S) and a Cd-resistant strain (R) were selected. The metal accumulation, growth and development, reproduction, and antioxidant enzyme activities in these strains were analyzed. The results showed that R-strain organisms had enhanced juvenile survivorship, increased Cd accumulation, and increased adult female fecundity when compared with S-strain. The larval enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase (GST) in R-strain larvae were higher than those in S-strain larvae when fed diets with or without Cd. This indicates that Cd resistance in B. peregrina larvae is mediated by SOD, CAT, GR, and GST.     

Activities of enzymes that detoxify superoxide anion and related toxic oxyradicals in Trichoplusia ni

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.     

Overwintering strategy of endoparasitoids in Chilo suppressalis: a perspective from the cold hardiness of a host

Although parasitoids ultimately kill their host, koinobiont parasitoids must protect not only themselves but also their hosts against extreme environments. In this study, the parasitism rate of Chilo suppressalis Walker (Lepidoptera: Pyralidae) was investigated, and the average body weights, supercooling points, and concentrations of glycerol (acting as a cryoprotectant) in the hemolymph were compared between parasitized and non‐parasitized larvae. Five species of koinobiont endoparasitoids parasitized the overwintering C. suppressalis larvae and the total parasitism rate was 47.6% (n = 1 537). Average body weight of parasitized larvae was significantly lower than that of non‐parasitized larvae, and the parasitism rate of the lighter group (20–30 mg) was highest. The supercooling point of parasitized C. suppressalis larvae (?15.7 ± 0.3 °C) was significantly lower than that of the non‐parasitized larvae (?14.3 ± 0.2 °C). In addition, supercooling points were not correlated with body weights between parasitized and non‐parasitized larvae, indicating that cold hardiness of parasitized larvae was enhanced by endoparasitoids. Furthermore, the concentration of glycerol in the hemolymph was significantly higher in parasitized larvae (205.0 ± 7.1 μmol ml^?1) than in non‐parasitized larvae (169.8 ± 14.4 μmol ml^?1), which suggests that the mechanism that decreases the supercooling point of parasitized larvae was associated with glycerol. All these results indicated that the cold hardiness of parasitized C. suppressalis larvae was enhanced by their endoparasitoids, which benefitted overwintering endoparasitoids.     

Effect of temperature on antioxidant enzymatic activity in the Pacific white shrimp Litopenaeus vannamei in a BFT (Biofloc technology) system

A 10-day trial was conducted to evaluate the effect of temperature on the antioxidant system of Litopenaeus vannamei in a biofloc technology system. Four treatments in triplicate tanks were assigned to the following temperatures: 15, 21, 27 (control), and 33 °C and the water quality parameters were monitored every day. For all enzyme assays, the hemolymph cells lysate of six shrimp per treatment was collected. Lipid peroxidation (LPO) was assessed by determining the content of thiobarbituric acid-reactive substances (TBARS); the activities of catalase (CAT) and glutathione-S-transferase (GST) were also evaluated. The results of TBARS showed that shrimp reared at 15 and 21 °C presented an increase of 407% (240 h) and 339% (120 h), respectively. L. vannamei exposed to 15 °C augmented in 186% (24 h) the activity of CAT. Moreover, shrimp of 21 °C group also increased CAT activity in 228% (6 h). GST presented the strongest variation reaching 1437% in shrimp of 15 °C for 6 h and 1425% of the 21 °C treatment at the same time. All these results were compared to the initial time (27 °C). Moreover, the antioxidant system was not sufficient to counteract LPO; therefore, the animals reared in 15 and 21 °C presented higher enzyme activities, suggesting that cold water can induce the oxidative stress in L. vannamei.     

Cold hardiness and overwintering strategy of the pink maize stalk borer,Sesamia nonagrioides Lef (lepidoptera,noctuidae)

The cold-hardening capacity of larvae of the pink maize stalk borer,Sesamia nonagrioides Lef., was examined. Supercooling points (SCPs) of field collected diapausing larvae from south-east and south-west France and non-diapausing and diapausing laboratory-reared larvae did not differ and ranged between –5 and –8°C. Thus, this insect possesses sufficient supercooling ability to avoid freezing over its normal environmental temperature ranges. Despite this, we found thatSesamia presents paradoxical cold reactions. Mortality of cold acclimated diapausing larvae after short-term exposure to temperatures above the SCP is high, supporting the view thatSesamia is cold-sensitive. On the other hand,Sesamia could survive freezing for at least 24 h to temperatures close to the SCP. This ability does not seem to be related to haemolymph trehalose, the sole cold-accumulated compound detected by gas chromatography and mass spectrometry. Despite the mildness of the winter 1990–1991, only 5% of the field population survive and pupate in April. The main part of the population died from November to January, the period during which larvae were mainly located in the part of the corn stem above the ground and experienced air temperatures. After January, all surviving larvae were excuusively located in the root, 10 cm below the soil, where they experienced milder temperatures than air. They exhibited a constant low rate of mortality, possibly independent of the cold. In their current distribution area, survival of overwintering larvae ofS. nonagrioides is only related to the microclimate of the overwintering site and freezing tolerance capacity seems to be irrelevant. This study allows us to propose a non-pollutant pest control method based on the behavioral strategy of this insect.     

Effects of redox cycling compounds on glutathione content and activity of glutathione-related enzymes in rainbow trout liver

In fish, as in other aerobic organisms, glutathione and glutathione-related enzymes are important components in the defences against oxidative stress. To study if hepatic glutathione levels and/or activities of glutathione-related enzymes can act as indicators of oxidative stress in fish, we injected rainbow trout (Oncorhynchus mykiss) intraperitoneally with paraquat (PQ), menadione (MD), naphthazarin (DHNQ), or beta-naphthoflavone (beta-NF), all known to cause a rise in reactive oxygen species (ROS). After 2 and 5 days of exposure, we measured the activities of hepatic glutathione peroxidase (GPox), glutathione S-transferase (GST), gamma-glutamylcysteine synthetase (GCS), and glutathione reductase (GR). We also measured total glutathione (tGSH) and oxidised glutathione (GSSG) in the liver of fish treated with PQ and MD. All chemicals caused an increase in GR activity after 5 days, which ranged from 160% in fish treated with beta-NF to 1,500% in fish treated with PQ. All chemicals except beta-NF caused moderate elevation in GST activity; GPox activity was lower in fish treated with DHNQ and MD, while GCS activity increased twofold in the fish treated with DHNQ, without being affected by beta-NF, PQ or MD. After 5 days of treatment with PQ or MD, tGSH content was elevated. Our findings demonstrated that of the parameters included in the study, GR activity was the most responsive to treatment with redox cycling compounds, indicating that GR activity is a promising biomarker of such compounds and possibly indicating oxidative stress in rainbow trout.     

EFFECT OF A HIGH TEMPERATURE ON VITELLOGE-NESIS IN THE JAPANESE OAK SILKWORM,ANTHERAEA YAMAMAI (LEPIDOPTERA: SATURNIIDAE)*

Abstract The effect of a high temperature, i. e. 32°C. on vitellogenesis of the Japanese oak silkworm, Antheraea yamamai (Lepidoptera: Saturniidae) was markedly significant. Its extent was dependent on the development stage of the silkworm exposed to 32°C. When exposed to 32 °C since the 1st day after cocooning, titres of both vitellogenin (Vg) and soluble proteins in the fat body and hemolymph of mature larvae were evidently lower than those at 26°C. When pupae were maintained at 32°C since the 1st day after pupation. the titres of Vg in the fat body showed no significant difference from those at 26°C, but those in the hemolymph and the titres of vitellin (Vt) in the ovary mostly were obviously lower in contrast to those at 26°C. While exposed to 32°C since the 6th day after pupation, at most instance the tires of Vg both in the fat body and hemolymph were not markedly different from those at 26°C, and those of Vt in the ovary were significantly higher than those at 26°C, In addition, the changes in the titres of soluble proteins in the fat body and hemolymph as well as the ovary were monitored when pupae were maintained at 32°C since the 1st or 6th day after pupation. It is recommended that both mature larvae and pupae at cocooning stage and earlier pupal stage should not be exposed to 32°C when the silkworm is reared for egg raising.     

Subcellular distribution and activities of superoxide dismutase,catalase, glutathione peroxidase,and glutathione reductase in the southern armyworm,Spodoptera eridania

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.     

In vitro release of lipophorin from the fat body of nondiapause and diapause larvae of the Southwestern corn borer,Diatraea grandiosella

The release of lipophorin and total protein was examined from the fat body of nondiapause and diapause larvae of the southwestern corn borer, Diatraea grandiosella, incubated in vitro in Grace's medium. The characteristics of the released lipophorin were compared to those of the high-density lipophorin present in the hemolymph of nondiapause and diapause larvae. Over a 4 h incubation period, the fat body of nondiapause larvae released about 1.5 times more total protein and 2 times more lipophorin per mg dry weight than did that of diapause larvae. Lipophorin isolated from the medium in which fat bodies of nondiapause and diapause larvae had been incubated and from the plasma of nondiapause and diapause larvae had similar mean densities of 1.115, 1.112, 1.117 and 1.119 g/ml, respectively. Although the lipid classes detected in lipophorin isolated from the fat body incubation medium and hemolymph were identical, more polar lipids and less diacylglycerol were associated with lipophorin isolated from fat body incubation medium then were associated with lipophorin isolated from the hemolymph. Sterols accounted for about 11% of the total lipids of lipophorin isolated from the fat body incubation medium, whereas they accounted for about 20% of the total lipids of lipophorin from hemolymph. We conclude that the fat body of feeding nondiapause larvae and nonfeeding diapause larvae releases high-density lipophorin.