Mercury induced time-dependent alterations in lipid profiles and lipid peroxidation in different body organs of cat-fish Heteropneustes fossilis

The effects of mercuric chloride (HgCl2) on lipid profiles and lipid peroxidation in different body organs of fresh water cat-fish Heteropneustes fossilis were studied. The daily exposure of HgCl2 0.2 mg/L for 10, 20 and 30 days depleted the total lipids in brain. But the content of phospholipids enhanced significantly at 30 days. Significant diminution in C/P ratio was discernible with 30 days of exposure following mercury toxicosis. Liver exhibited elevated levels of total lipids, phospholipids, cholesterol and C/P ratio. Interestingly kidney showed marked decrease in the concentration of total lipids, cholesterol and C/P ratio at higher exposure. However, the phospholipid values increased during the longer exposure. The content of total lipids and phospholipids was high in muscle but the level of cholesterol and C/P ratio were depleted. Significant increment in lipid peroxidation was discernible in brain, liver and muscle. In kidney the rate of lipid peroxidation was significantly reduced. The results suggest that exposure of HgCl2 enhances the peroxidation of endogenous lipids in brain, liver and muscle. Interestingly the lipid contents are affected differently in different body organs.     

Organophosphate dichlorvos induced dose‐related differential alterations in lipid levels and lipid peroxidation in various regions of the fish brain and spinal cord

Abstract

The effect of dichlorvos (DDVP) (0–0, dimethyl 2: 2‐dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose‐related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS.     

Ecotoxicological responses of the earthworm Eisenia fetida exposed to soil contaminated with HHCB

Although polycyclic musks have been shown to cause lethal and sub-lethal effects on organisms, their biochemical toxicity to earthworms is not well understood. In the current study, we investigated the responses of antioxidant systems and lipid peroxidation after exposing Eisenia fetida to soil contaminated with 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran (HHCB). Significant increase in lipid peroxidation level was observed on day 14 at two high concentrations, 50 and 100 mg kg⁻¹. Among antioxidant enzymes, the primary response to chronic HHCB exposure can be attributed to superoxide dismutase (SOD) and catalase (CAT). Of the two enzymes, SOD exhibited more sensitive response to HHCB stress. In addition, these two enzymes could have a combined effect on fighting damage by reactive oxygen species, evidenced by a marked relationship between lipid peroxidation and enzyme activity. On the other hand, dose-dependent inhibition of peroxidase (POD) activity has been observed throughout the test. The results suggest that the variations in investigated parameters of E. fetida could be used as responsive biomarkers for oxidative stress caused by HHCB in a soil environment.     

Organophosphate dichlorvos induced dose-related differential alterations in lipid levels and lipid peroxidation in various regions of the fish brain and spinal cord

The effect of dichlorvos (DDVP) (0-0, dimethyl 2:2-dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose-related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS.     

Adaptive alterations in the fatty acids composition under induced oxidative stress in heavy metal-tolerant filamentous fungus Paecilomyces marquandii cultured in ascorbic acid presence

The ability of the heavy metal-tolerant fungus Paecilomyces marquandii to modulate whole cells fatty acid composition and saturation in response to IC₅₀ of Cd, Pb, Zn, Ni, and Cu was studied. Cadmium and nickel caused the most significant growth reduction. In the mycelia cultured with all tested metals, with the exception of nickel, a rise in the fatty acid unsaturation was noted. The fungus exposure to Pb, Cu, and Ni led to significantly higher lipid peroxidation. P. marquandii incubated in the presence of the tested metals responded with an increase in the level of linoleic acid and escalation of electrolyte leakage. The highest efflux of electrolytes was caused by lead. In these conditions, the fungus was able to bind up to 100 mg?g^?1 of lead, whereas the content of the other metals in the mycelium was significantly lower and reached from 3.18 mg?g^?1 (Cu) to 15.21 mg?g^?1 (Zn). Additionally, it was shown that ascorbic acid at the concentration of 1 mM protected fungal growth and prevented the changes in the fatty acid composition and saturation but did not alleviate lipid peroxidation or affect the increased permeability of membranes after lead exposure. Pro-oxidant properties of ascorbic acid in the copper-stressed cells manifested strong growth inhibition and enhanced metal accumulation as a result of membrane damage. Toxic metals action caused cellular modulations, which might contributed to P. marquandii tolerance to the studied metals. Moreover, these changes can enhance metal removal from contaminated environment.     

Triphenyltin alters lipid homeostasis in females of the ramshorn snail Marisa cornuarietis

Molluscs are sensitive species to the toxic effects of organotin compounds, particularly to masculinisation. Both tributyltin (TBT) and triphenyltin (TPT) have been recently shown to bind to mollusc retinoid X receptor (RXR). If RXR is involved in lipid homeostasis, exposure to TPT would have an immediate effect on endogenous lipids. To test this hypothesis, the ramshorn snail Marisa cornuarietis was exposed to environmentally relevant concentrations of TPT (30, 125, 500 ng/L as Sn) in a semi-static water regime for 7 days. Percentage of lipids and total fatty acid content decreased significantly in TPT-exposed females while the activity of peroxisomal acyl-CoA oxidase, involved in fatty acid catabolism, increased. In addition, fatty acid profiles (carbon chain length and unsaturation degree) were significantly altered in exposed females but not in males. This work highlights the ability of TPT to disrupt lipid metabolism in M. cornuarietis at environmentally realistic concentrations and the higher susceptibility of females in comparison to males.     

Dimethoate-induced oxidative stress and DNA damage in Oncorhynchus mykiss

The present study was conducted in order to investigate pro-oxidant activity of dimethoate in liver and brain tissues following sublethal pesticide exposure for 5, 15 and 30 d by using SOD, GPx, CAT enzyme activities and lipid peroxidation as biomarkers as well as DNA damaging potential via detecting% Tail DNA, Tail moment and Olive tail moment as endpoints in erythrocytes of Oncorhynchus mykiss in an in vitro experiment. Antioxidant enzyme activities were found to elicit two staged response which was an initial induction followed by a sharp inhibition in liver tissue while a sustained increase in GPx activity and slight stimulation in SOD activity were detected in brain tissue. Lipid peroxidation showed an ascending pattern throughout the exposure period in both tissues and a decreasing trend was determined in tissue protein levels which was proved to be positively correlated with duration. Similar findings were obtained from outcomes preferred to quantify DNA damage and TM was decided to reflect the extent of damage more sensitively because of determined positive correlation with concentrations applied. Considering these results, it can be concluded that oxidative stress condition evoked by dimethoate could not be responded effectively and genotoxic nature of pesticide was proven by determined clastogenic effect possibly via being an alkylation agent or stimulating the production of reactive species.     

Effect of binary combination of deltamethrin+MGK-264 on the levels of phospholipid and lipid peroxidation in the snail Lymnaea acuminata

Effect of sublethal treatment of (40% and 60% of 48 h LC50) of deltamethrin+MGK on phospholipid level and rate of lipid peroxidation in nervous and foot tissue of Lymnaea acuminata were studied. Maximum reduction in phospholipid (24.10%) level and increase in rate of lipid peroxidation (586.8%) were observed in foot tissue of snail exposed to 60% of 48 h LC50 of deltamethrin+MGK 264 for 96 h. Alterations in the levels of phospholipids and rate of lipid peroxidation were time and concentration dependent. Use of MGK-264 with deltamethrin increases the toxicity of deltamethrin and their action on membrane phospholipids and rate of lipid peroxidation.     

Copper and zinc induction of lipid peroxidation and effects on antioxidant enzyme activities in the microalga Pavlova viridis (Prymnesiophyceae)

The metal-induced lipid peroxidation and response of antioxidative enzymes have been investigated in the marine microalga Pavlova viridis to understand the mechanisms of metal resistance in algal cells. We have analyzed superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activities and glutathione (GSH) contents in microalgal cells grown at different concentrations of copper and zinc. In response to each metal, lipid peroxidation was enhanced with the increase of concentrations, as an indication of the oxidative damage caused by metal concentration assayed in the microalgae cells. Exposure of P. viridis to the two metals caused changes in enzyme activities in a different manner, depending on the metal assayed: after copper treatments, total SOD activity was enhanced, while it was reduced after zinc exposure. Copper and zinc stimulated the activities of CAT and GSH whereas GPX showed a remarkable increase in activity in response to copper treatments and decrease after zinc treatments. These results suggest that an activation of some antioxidant enzymes was enhanced to counteract the oxidative stress induced by the two metals.     

Lead induced changes in antioxidant metabolism of horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and bengalgram (Cicer arietinum L.)

One-month old horsegram (Macrotyloma uniflorum (Lam.) Verdc. cv VZM1) and bengalgram (Cicer arietinum L. cv Annogiri) were exposed to different regimes of lead stress as Pb(NO3)2 at 0, 200, 500 and 800 ppm concentrations. The extent of oxidative damage as the rate of lipid peroxidation, antioxidative response and the accumulation of lead in roots and shoots of both plants were evaluated after 12 days of lead stress. Lead (Pb) treated plants showed increased levels of lipid peroxidation as evidenced from the increased malondialdehyde content coupled with the increase in the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), glutathione S-transferase (GST) compared to control (untreated) plants. Lead stress caused significant changes in the activity of antioxidative enzymes. The effect of lead was found to be concentration dependent. Higher concentration of lead (800 ppm) resulted 2- to 3-fold increase in SOD, catalase and peroxidase activities, 3- to 5-fold increase in GR activity and 3- to 4-fold increase in GST activity in roots and leaves of both horsegram and bengalgram plants. Lead stress caused a significant increase in the rate of peroxidation as showed in the levels of malondialdehyde content in roots and leaves of both plant species. Horsegram registered lower Pb accumulation than bengalgram, however localization of Pb was greater in roots than leaves in both plants. In general, lipid peroxide levels and antioxidative enzyme activities were higher in horsegram than bengalgram and also more in roots than leaves which best concordance with the lead contents of both the plants and organs. These results suggest that Pb toxicity causes oxidative stress in plants and the antioxidative enzymes SOD, CAT, POD, GR, GST could play a pivotal role against oxidative injury.     

Lead tolerance and physiological adaptation mechanism in roots of accumulating and non-accumulating ecotypes of Sedum alfredii

Background, aim and scope

Lead (Pb) accumulation in soils affects plants primarily through their root systems. The aim of this study was to investigate early symptoms of the loss of membrane integrity and lipid peroxidation in root tissues and physiological adaptation mechanism to Pb in accumulating ecotypes (AE) and non-accumulating ecotypes (NAE) of Sedum alfredii under Pb stress in hydroponics.

Methods and results

Histochemical in situ analyses, fluorescence imaging, and normal physiological analysis were used in this study. Pb accumulation in roots of both AE and NAE increased linearly with increasing Pb levels (0?C200???M), and a significant difference between both ecotypes was noted. Both loss of plasma membrane integrity and lipid peroxidation in root tissues became serious with increasing Pb levels, maximum tolerable Pb level was 25 and 100???M for NAE and AE, respectively. Pb supplied at a toxic level caused a burst of reactive oxygen species (ROS) in root cells in both ecotypes. However, the root cells of AE had inherently higher activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), and lipoxygenase (LOX) in control plants, and the induction response of these antioxidant enzymes occurred at lower Pb level in AE than NAE. AE plants maintained higher ascorbic acid and H₂O₂ concentrations in root cells than NAE when exposed to different Pb levels, and Pb induced more increase in dehydroascorbate (DHA), catalase (CAT), and ascorbate peroxidase (APX) in AE than NAE roots.

Discussion and conclusion

Results indicate that histochemical in situ analyses of root cell death and lipid peroxidation under Pb short-term stress was sensitive, reliable, and fast. Higher tolerance in roots of accumulating ecotype under Pb stress did depend on effective free oxygen scavenging by making complex function of both constitutively higher activities and sensitive induction of key antioxidant enzymes in root cells of S. alfredii.     

Effects of different inorganic arsenic species in Cyprinus carpio (Cyprinidae) tissues after short-time exposure: Bioaccumulation, biotransformation and biological responses

Differences in the toxicological and metabolic pathway of inorganic arsenic compounds are largely unknown for aquatic species. In the present study the effects of short-time and acute exposure to As^III and As^V were investigated in gills and liver of the common carp, Cyprinus carpio (Cyprinidae), measuring accumulation and chemical speciation of arsenic, and the activity of glutathione-S-transferase omega (GST Ω), the rate limiting enzyme in biotransformation of inorganic arsenic. Oxidative biomarkers included antioxidant defenses (total glutathione-S-transferases, glutathione reductase, glutathione, and glucose-6-phosphate dehydrogenase), total scavenging capacity toward peroxyl radicals, reactive oxygen species (ROS) measurement and lipid peroxidation products. A marked accumulation of arsenic was observed only in gills of carps exposed to 1000 ppb As^V. Also in gills, antioxidant responses were mostly modulated through a significant induction of glucose-6-phosphate dehydrogenase activity which probably contributed to reduce ROS formation; however this increase was not sufficient to prevent lipid peroxidation. No changes in metal content were measured in liver of exposed carps, characterized by lower activity of GST Ω compared to gills. On the other hand, glutathione metabolism was more sensitive in liver tissue, where a significant inhibition of glutathione reductase was concomitant with increased levels of glutathione and higher total antioxidant capacity toward peroxyl radicals, thus preventing lipid peroxidation and ROS production. The overall results of this study indicated that exposure of C. carpio to As^III and As^V can induce different responses in gills and liver of this aquatic organism.     

Physiological effects of mercury in the lichens Cladonia arbuscula subsp. mitis (Sandst.) Ruoss and Peltigera rufescens (Weiss) Humb

This study aimed at investigating the cellular distribution of Hg in the lichens Cladonia arbuscula subsp. mitis and Peltigera rufescens treated with Hg²⁺ and at testing if Hg treatment affects selected physiological parameters. In both species, increasing Hg accumulation under increasing Hg supply in the treatment solutions was found. P. rufescens showed a higher intracellular accumulation. Photosynthetic parameters were negatively affected in both species, as indicated by the decrease in photosynthetic pigments content, photosynthetic efficiency and chlorophyll integrity. Cell membranes of both species endured damage as indicated by the increase in the concentration of products of lipid peroxidation and decrease in ergosterol content. Nevertheless, differences between the two species were found, suggesting a differential sensitivity to Hg.     

The effect of copper ions on the lipid composition of subcellular membranes in Hydrilla verticillata

The paper studies changes in the content and composition of lipids in the membranes of chloroplasts, mitochondria and microsomes of the aquatic plant Hydrilla verticillata exposed to copper ions (100 μM; 1, 3, 6 and 24 h). The rate of copper accumulation and the coefficient of its extraction by the plant were also determined. The presence of copper in the incubation medium and its accumulation in the plant tissues decreased the content of photosynthetic pigments, stimulated lipid peroxidation and enhanced membrane permeability. The gradual accumulation of copper in the plant tissues was accompanied by specific changes in the composition of lipids: the content of sulfolipids (SQDG) in chloroplasts declined; the content of monogalactosyl diacylglycerols (MGDG), digalactosyl diacylglycerols (DGDG) and phosphatidyl glycerols (PG) in chloroplasts and mitochondria grew after an hour of copper exposure; and the content of all the lipids except phosphatidic acids (PA) decreased after 3 h of exposure. The decline in the content of phosphatidyl cholines (PC) was first observed in the membranes of microsomes (after an hour of exposure) and later in the membranes of chloroplasts and mitochondria (after 3-6 h of exposure). The experiments with incorporation of [2-¹⁴C]sodium acetate into fatty acids of polar lipids showed that in parallel with lipid destruction, there took place an intensive and specific renewal of the lipid pool of subcellular membrane fractions.     

Effects of environmentally relevant concentrations of metallic compounds on the flatfish Scophthalmus maximus: biomarkers of neurotoxicity,oxidative stress and metabolism

Flatfish species, such as the turbot (Scophthalmus maximus), are common targets for toxic effects, since they are exposed through the food chain (ingestion of contaminated preys) and are in direct contact with the waterborne contaminant and sediments. Furthermore, these fish species live in close proximity to interstitial water that frequently dissolves high amounts of contaminants, including metals. Despite this significant set of characteristics, the present knowledge concerning flatfish contamination and toxicity by metals is still scarce. To attain the objective of assessing the effects of metals on a flatfish species, S. maximus specimens were chronically exposed to lead, copper and zinc, at ecologically relevant concentrations, and biochemical (oxidative stress: catalase and glutathione S-transferases activities, and lipid peroxidation; neurotoxicity: cholinesterase activity) parameters were assessed on selected tissues (gills and liver). Copper had no significant effects on all tested parameters; lead was causative of significant increases in liver GSTs activities and also in lipoperoxidation of gill tissue; exposure to zinc caused a significant increase in catalase activity of gill tissue. None of the tested metals elicited noteworthy effects in terms of neurotoxicity. The obtained results showed that only the metal lead is of some environmental importance, since it was able to cause deleterious modifications of oxidative nature at relevant concentrations.     

Biochemical effects of acetaminophen in aquatic species: edible clams Venerupis decussata and Venerupis philippinarum

Acetaminophen (paracetamol) is one of the most used pharmaceutical drugs, due to its antipyretic and analgesic properties that turn it into a primary choice in varied pathologies and conditions. However, and despite its massive use, acetaminophen is not exempt of adverse effects, especially when administered in over dosage, which are related to the formation of toxic metabolites by oxidative pathways. It is thus possible to observe that toxicity caused by acetaminophen is usually mediated by reactive oxygen species and can result in multiple effects, ranging from protein denaturation to lipid peroxidation and DNA damage. The occurrence of acetaminophen has been reported in the aquatic environment, being important to address the potential exertion of toxic effects on nontarget environmentally exposed organisms. The present study intended to characterize the effects of acute acetaminophen exposure on physiological traits (antioxidant defense, oxidative damage) of two species of bivalves, namely, the edible clams Venerupis decussata and Venerupis philippinarum. Results showed a significant increase in all oxidative stress biomarkers, evidencing the bioactivation of acetaminophen into a deleterious prooxidant, triggering the onset of deleterious effects. Furthermore, strong interspecific differences were observed among responses of the two tested species, which was a major issue due to intrinsic ecological implications when one considers that both species share the same habitat.     

Biological effects of palytoxin-like compounds from Ostreopsis cf. ovata: A multibiomarkers approach with mussels Mytilus galloprovincialis

Massive blooms of the harmful benthic dinoflagellate Ostreopsis cf. ovata are of growing environmental concern in the Mediterranean, having recently caused adverse effects on benthic invertebrates and also some intoxication episodes to humans.The toxicological potential of produced palytoxin-like compounds was investigated in the present study on a typical marine sentinel species, the mussel Mytilus galloprovincialis. Organisms were sampled during various phases of a O. cf. ovata bloom, in two differently impacted sites. The presence of the algal toxins was indirectly assessed in mussels tissues (mouse test and hemolysis neutralization assay), while biological and toxicological effects were evaluated through the measurement of osmoregulatory and neurotoxic alterations (Na⁺/K⁺-ATPase and acetylcholinesterase activities), oxidative stress responses (antioxidant defences and total oxyradical scavenging capacity), lipid peroxidation processes (level of malondialdehyde), peroxisomal proliferation, organelle dysfunctions (lysosomal membrane stability, accumulation of lipofuscin and neutral lipids), immunological impairment (granulocytes percentage).Obtained results demonstrated a significant accumulation of algal toxins in mussels exposed to O. cf. ovata. These organisms exhibited a marked inhibition of the Na⁺/K⁺-ATPase activity and alterations of immunological, lysosomal and neurotoxic responses. Markers of oxidative stress showed more limited variations suggesting that toxicity of the O. cf. ovata toxins is not primarily mediated by an over production of reactive oxygen species. This study provided preliminary results on the usefulness of a multi-biomarker approach to assess biological alterations and toxicological events associated to blooms of O. cf. ovata in marine organisms.     

Assessment of imposex and butyltin concentrations in Gemophos viverratus (Kiener, 1834), from São Vicente,Republic of Cabo Verde (Africa)

This work constitutes the first assessment of tributyltin (TBT) pollution levels in the Republic of Cabo Verde (Africa) and proposes the marine gastropod Gemophos viverratus (Kiener, 1834) as a new bioindicator of TBT pollution in the Macaronesia and west coast of Africa. Specimens were collected between August and October 2012 along a gradient of naval traffic in São Vicente Island. The results clearly indicate an increase of imposex levels (percentage of females affected with imposex, 0–100 %; vas deferens sequence index, 0–4.1; relative penis length index, 0–54.6 %) and female TBT contamination (from 5 to 37 ngSn g^?1 dry weight (dw)) from outside to inside the harbour of Porto Grande Bay and identify this area as the focus of TBT pollution in the island. The butyltin degradation index for G. viverratus tissues ranged between 1.3 and 2.2, which being above 1 suggests that a considerable part of TBT inputs to the bay may not be very recent. Sterile females were found inside the harbour with an incidence up to 21.4 %. Considering the existence of a planktonic veliger stage in the life cycle of G. viverratus, it is expected that recruitment of newborn individuals can be supplied from unaffected breeding females inside and outside the Porto Grande Bay, resulting in a reduced impact of TBT pollution on population abundance. G. viverratus is very promising to be used as a simple, inexpensive and efficient novel tool for TBT pollution biomonitoring in the Macaronesia and west coast of Africa, a region for which there is an astonishing lack of information concerning levels and ecological impacts of TBT pollution.     

The non-target organism Caenorhabditis elegans withstands the impact of sulfamethoxazole

The widespread usage of antibiotics in agriculture leads to releases into the environment, but there is insufficient knowledge of the side-effects on non-target organisms. Therefore, we investigated the effects of the sulfonamide-antibiotic sulfamethoxazole (SMX) on Caenorhabditis elegans at phenotypic, biochemical and molecular biological levels. Multiple endpoints, including life history traits, thermal stress resistance and lipid peroxidation, as well as gene expression profiles, were determined after exposure of the nematodes to SMX. In contrast to expectations, SMX prolonged the lifespan and increased both the body size and pharynx pumping rate. On the other hand, SMX delayed reproductive timing and caused lipid peroxidation. The total number of offspring and thermal stress resistance were unaffected. The up-regulation of hsp-16.1 indicated stress in general and the increased lipid peroxidation oxidative stress in particular. This oxidative stress indicated that mitohormesis was the likely cause of the longevity and that enhanced pumping frequency was probably the reason for the increased growth. The sole adverse effect was delayed initial reproduction. This delay, however, can be crucial for r-strategists, such as the bacterivorous model animal used, in sustaining their populations in the environment in the presence of predators. Bacterivorous animals, in turn, are essential to maintaining nutrient recycling via the microbial loop.