Changes in the activities of some digestive enzymes of Channa punctatus, exposed chronically to mercuric chloride

The effect of a chronic exposure to sublethal concentration of mercuric chloride (0.3 mg/l) on the activities of some enzymes in the digestive system of the teleost fish Channa punctatus was examined after 15 and 30 days of treatment. Glucose-6-phosphatase was significantly inhibited in the intestine and pyloric caeca. No marked alterations were observed in the activities of maltase and lactase except for elevation in maltase activity and inhibition in lactase activity in the intestine and pyloric caeca after 15 days of treatment. Three peptidases (aminotripeptidase, glycylglycine dipeptidase and glycyl-1-leucine dipeptidase) showed decreased activities in all parts of the digestive system. A decrease was also observed in the activity of lipase except for the stomach where inhibition after 15 days was insignificant. The results indicate that the activities of all the enzymes examined are inhibited in intestine and pyloric caeca and digestion of proteins and lipids may be more affected by mercury than the digestion of some carbohydrates.     

Effects of cadmium exposure on digestive enzymes, antioxidant enzymes, and lipid peroxidation in the freshwater crab Sinopotamon henanense

In this study, the effects of cadmium (Cd) stress on the activities of disaccharidases (sucrase, lactase, and maltase), amylase, trypsin, pepsase, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) content in the alimentary system of freshwater crabs Sinopotamon henanense were studied. Results showed that the enzyme activities in the stomach, intestine, and hepatopancreas changed with Cd concentration. In terms of digestive enzymes, Cd exposure had an inhibitory effect on the activities of the disaccharidases, amylase, and pepsase (only in the stomach). Significant induction of trypsin activity by Cd at a lower concentration was observed, but as Cd concentration increased, trypsin activity decreased. Maltase activity showed a slight recovery after inhibition by Cd. The activities of SOD and CAT increased initially and decreased subsequently. Cd significantly inhibited the activity of GPx. MDA content increased with increasing concentration of Cd. These results showed that acute Cd exposure led to harmful effects on the alimentary system of crabs, which are likely linked to Cd induced oxidative stress.     

Chronic effects of mercuric chloride on the activities of some enzymes in certain tissues of the fresh water murrel,

Alterations in the activities of some enzymes in the brain, gills, intestine, kidney, liver and muscles have been examined in the fresh water murrel, , after exposure to a sublethal concentration of mercuric chloride (3 μg/1) for 15, 30 and 60 days. The results revealed that after 15 days of exposure amino acid oxidase activity was elevated in brain and liver and inhibited in intestine. The activity of xanthine oxidase was increased in gills, and inhibited in kidney. Thirty days exposure produced significant inhibition in the activities of malate dehydrogenase in liver, glutamate dehydrogenase in gills and brain, aminoacid oxidase in gills, and xanthine oxidase in liver and intestine. In contrast, glutamate dehydrogenase in intestine, kidney and liver and aminoacid oxidase in brain and liver were elevated. After 60 days of treatment, a decrease in the activity of glucose-6-phosphatase was recorded in gills, intestine, kidney and liver. Hexokinase activity in kidney and liver, and malate dehydrogenase in all the six tissues were inhibited. Glutamate dehydrogenase activity in intestine, kidney and liver remained higher than in control fish. In brain, kidney and liver the activity of aminoacid oxidase was elevated, but in gills the enzyme activity decreased. Xanthine oxidase activity was inhibited in intestine and liver.     

Chronic effects of mercuric chloride on the activities of some enzymes in certain tissues of the fresh water murrel, Channapunctatus

Alterations in the activities of some enzymes in the brain, gills, intestine, kidney, liver and muscles have been examined in the fresh water murrel, $\text{Channa}$$\text{punctatus}$, after exposure to a sublethal concentration of mercuric chloride (3 μg/1) for 15, 30 and 60 days. The results revealed that after 15 days of exposure amino acid oxidase activity was elevated in brain and liver and inhibited in intestine. The activity of xanthine oxidase was increased in gills, and inhibited in kidney. Thirty days exposure produced significant inhibition in the activities of malate dehydrogenase in liver, glutamate dehydrogenase in gills and brain, aminoacid oxidase in gills, and xanthine oxidase in liver and intestine. In contrast, glutamate dehydrogenase in intestine, kidney and liver and aminoacid oxidase in brain and liver were elevated. After 60 days of treatment, a decrease in the activity of glucose-6-phosphatase was recorded in gills, intestine, kidney and liver. Hexokinase activity in kidney and liver, and malate dehydrogenase in all the six tissues were inhibited. Glutamate dehydrogenase activity in intestine, kidney and liver remained higher than in control fish. In brain, kidney and liver the activity of aminoacid oxidase was elevated, but in gills the enzyme activity decreased. Xanthine oxidase activity was inhibited in intestine and liver.     

Effect of four experimental insecticides on enzyme activities and levels of adenosine triphosphate in mineral and organic soils

Abstract

A laboratory study was conducted to determine the effect of four experimental insecticides, DOWCO429X, DPX43898, tefluthrin and trimethacarb, on enzyme activities and levels of adenosine 5'‐triphosphate (ATP) in mineral and organic soils. DOWCO429X decreased urease activity in organic soil after 7 days while a stimulatory effect was observed with most treatments after 14 days. No inhibition on acetylene (C₂H₂) reduction by nitrogenase was evident with any of the insecticides in either soil. With the exception of DOWCO429X and tefluthrin at 7 days in organic soil, none of the insecticide treatments inhibited dehydrogenase activity in either soil. Dehydrogenase activity, measured by formazan formation, was greater in many samples in sandy loam than the control throughout the experiment. No inhibitory effect was observed on amylase activity after 2 or 3 days in sandy soil. A stimulatory effect was apparent in many samples after 2 days in organic soil. All insecticide treatments in sandy soil reduced invertase activity at 2 days. However, none of the experimental insecticides inhibited invertase activity after 3 days. A stimulatory effect in invertase activity was apparent in most cases at 2 days in organic soil and no difference was observed after 3 days. Phosphatase activity in insecticide treated samples was equal to or greater than that of control in sandy soil after 2 h. With the exception of DPX43898, the insecticides depressed phosphatase activity in most organic soil samples. The insecticides did not affect ATP levels in either soil. Results indicated that the chemical treatments at the levels tested did not significantly affect activities of enzymes or level of ATP in both soils.     

Effect and mechanism of action of methomyl and cypermethrin insecticides on kynurenine metabolizing enzymes of mouse liver

Abstract

The effect of methomyl and cypermethrin insecticides on the B₆‐dependent kynurenine hydrolase(KH) and kynurenine aminotransferase (KATE) was studied. These insecticides induced pronounced inhibition on the (KH) and (KATE) enzymes after single dose treatment. Repeated doses of methomyl induced inhibition on the (KH) and (KATE) activities, whereas repeated treatment with cypermethrin had no effect on the activities of these enzymes. In vitro methomyl inhibited (KH) and (KATE) enzymes at 10 M up to 10^‐3 M, through a competitive mechanism. Methomyl and cypermethrin are capable of causing alterations in the kynurenine metabolizing enzymes of mouse liver.     

Alteration in some biochemical and enzymological parameters in the snake head fish , exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Alteration in some biochemical and enzymological parameters in the snake head fish Channapunctatus, exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Toxicity and biochemical impact of certain oxime carbamate pesticides against terrestrial snail,Theba pisana (Müller)

Abstract

The bran toxic baits (0.5 % w/w) of five oxime carbamate pesticides; aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were tested for their molluscicidal activity against Theba pisana snails under Laboratory conditions. In addition, the in vivo effects of these compounds on seven vital enzymes namely Acetylcholin‐esterase (AchE), glutathion‐S‐transferase (GST), glutamic oxlaoacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), acid phosphatase (AcP), alkaline phosphatase (AIP), and adenosine triphosphatase (ATPase) activities of the snail tissue were also investigated after 1,3, and 5 days of exposure. The results showed that methomyl was the most potent candidate, whereas thiofanox was the least effective one against the snails. LT₅₀’s values of aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were 5.77, 4.69, 2.31, 3.97 and 6.67 days, respectively. Results of the potency of the tested pesticides against AchE activity were in harmony with the toxicity of these compounds to snails. AchE, AcP, and AIP activities were inhibited by the tested pesticides. GST activity was inhibited by aldicarb but stimulated by oxamyl and thiofanox. Methomyl and oxamyl lead to significant elevation of GOT and GPT, whereas thiofanox treated snail induced a reduction of both enzymes activities. Aldicarb and aldoxycarb caused significant induction of ATPase activity.     

Effect of crude oil contaminated sediment exposure on cytochrome P450 enzymes in the Australian asteroid Coscinasterias muricata

Levels of cytochrome P450 enzymes were measured in pyloric caeca microsomes of the asteroid Coscinasterias muricata following exposure to sediment with nominal concentrations of 0, 0.1 or 2 ml crude oil kg(-1) (dry weight) and subsequent depuration. No significant differences were observed in total cytochrome P450 levels or cytochrome P418 levels following the exposure period. However after five days of depuration, levels of total P450 in the pyloric caeca of C. muricata exposed to the highest oiled sediment concentration were significantly lower than in specimens exposed to the other treatments. Cytochrome P418 levels were inversely related to total P450 levels following exposure and subsequent depuration. Preliminary results show that levels of CYP1A-like immunopositive protein (CYP1A-like IPP) in exposed asteroids exhibited a concentration response relationship following the exposure period. Variations in CYP1A-like IPP levels observed during the depuration period may be influenced by the sublethal toxicity of hydrocarbons within the crude oil.     

Safening activity of natural hydroxamic acids and analogous compounds against herbicide injury to maize

Abstract

Safening activities of natural compounds DIMBOA, DIBOA, and MBOA, as well as synthetic 1,4‐benzoxazin‐3‐ones were tested against acetochlor and EPTC injuries to maize. No safening activities of natural products and from low to moderate activity of synthetic benzoxazinones were observed. In order to explain inefficacy of natural compounds we studied the influence of these molecules on enzymes participating in metabolic detoxication of acetochlor and EPTC. Pretreatment with DIMBOA elevated maize cytochrome P450 levels. Pretreatments with chemicals containing 1,4‐benzoxazin‐3‐one backbone did not alter glutathione S‐transferase enzyme activities. However, all natural products inhibited glutathione S‐transferase activity of roots and shoots in vitro after addition to the enzyme. Safening ineffectiveness of natural hydroxamic acids may be explained by their inhibitory effects on GST enzymes due to their reaction with sulfhydryl groups on the enzyme.     

Effects of synthetic pyrethroids and methidation on activities of some digestive enzymes in carp (Cyprinus carpio L.)

Abstract

The effects of pyrethroid pesticides (deltamethrin, permethrin and cypermethrin) and an organophosphate ester (methidation) on the activities of carp trypsin, α‐chymotrypsin, carboxypeptidase A and lipase were studied. The enzymes were isolated from the gastrointestinal tract and the effects of the pesticides were investigated during incubation for 5 min. The activity of trypsin was influenced only slightly by the presence of deltamethrin and methidation, whereas permethrin and cypermethrin caused significant inhibition. The pyrethroid pesticides at lower concentrations resulted in a slight activation of α‐chymotrypsin. Methidation inhibited the α‐chymotrypsin activity by about 20%. These pesticides modified the lipase activity to a lesser extent; the highest inhibition was measured with cypermethrin. The carboxypeptidase A activity was inhibited by both pyrethroid pesticides and methidation. The results suggest that these pesticides might interact with the active conformation of the studied hydrolytic enzymes, resulting in changes in their activities.     

Effects of Metsulfuron-Methyl on the Microbial Population and Enzyme Activities in Wheat Rhizosphere Soil

The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 μ g·g^?1 metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but the effects on common fungi and common actinomycete were not evident. In the meantime, the number of tolerant fungi increased greatly in the rhizosphere after the application of metsulfuron-methyl in contrast to the significant decrease of the amount of tolerant actinomycete. It indicates that fungi might turn into the dominant microbial type and actinomycete is the sensitive factor in the soil polluted by sulfonylurea residues. The population of aromatic compounds–decomposing bacteria, aerobic azotobacter, and nitrite bacteria all increased in the earlier period, but the aerobic azotobacter decreased rapidly in number 30 days later, and the amount of nitrite bacteria also showed a temporary decrease with time 15 days later. However, the denitrifying bacteria just began to increase significantly after the crops had grown for 50 days. The amount of sulfur-oxidizing bacteria gradually decreased with the growth of crops, and so were the sulfate-reducing bacteria after metsulfuron-methyl application. To all types of microorganisms, there were more microbes in rhizosphere samples than those in nonrhizosphere except aerobic azotobacter. It means the growth of wheat root system can stimulate the growth of most microorganisms. The activities of hydrogen peroxidase and polyphenol oxidase in soil samples after metsulfuron-methyl application were notably lower than those in the control, and the difference of the activities between the samples of rhizosphere and nonrhizosphere was evident. On the contrary, the activity of dehydrogenase was not inhibited by the application of metsulfuron-methyl, and the rhizosphere effect was not obvious either.     

Diazinon treatment effects on heart and skeletal muscle enzyme activities

Abstract

The effects of low levels of diazinon treatment on four marker enzymes in rat heart and skeletal muscle have been investigated. Adult male Wistar rats were treated twice a week with a dose of 0.5 ml‐kg^‐1day^‐1 diazinon for 28 weeks. Diazinon treated rats gained significantly less weight than Sham‐treated controls. Typical differences in Succinate dehydrogenase (SDH), Lactate dehydrogenase (LDH), Phosphofructo kinase (PFK) and Hexokinase (HK) activities were observed between heart and skeletal muscles. Diazinon feeding had no effect on heart, soleus, gastrocnemius and plantaris SDH, LDH and PFK enzyme activities after 28 weeks. HK activity was significantly increased in sham‐control soieus and plantaris muscles after 28 weeks. Diazinon feeding inhibited HK activity in plantaris muscle after 28 weeks treatment These results demonstrate that chronic low levels of diazinon have little effect on the glycolytic and oxidative activity in heart and skeletal muscle.     

Soil dehydrogenase, phosphomonoesterase and arginine deaminase activities in an insecticide treated groundnut (Arachis hypogaea L.) field

Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2 pyridyl phosphorothioate) 20 EC and Quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) 25 EC, were applied in groundnut (Arachis hypogaea L.) field as seed treatment at 25 ml/kg and soil treatment at 4 l/ha in 1998 and 1999. The residues of these insecticides were monitored during the entire crop season and their effect on the soil enzymes dehydrogenase, phosphomonoesterase and arginine deaminase were studied. Ninety nine percent of chlorpyrifos residues were dissipated within 60 days from seed treated soil and 98% dissipation was observed in soil treated field for the same days. Its half lives in seed treated soil were 8 days and 7 days and in soil treated field were 9.2 days in and 7.5 days in 1998 and 1999 respectively. Dissipation of quinalphos in comparison to chlorpyrifos was slow both in seed treated and soil treated field. Eighty seven percentage to 92% dissipation of quinalphos residues were observed from seed treated soil and 98% residues were dissipated from soil treated field within 75 days. Its half lives in seed treated soil were 20 days and 18 days and in soil treated field, its half lives were 13 days and 17 days 1998 and 1999 respectively. Inhibition in dehydrogenase activity followed by recovery was observed both in seed and soil treatments with chlorpyrifos. An inhibition of 17.2% was estimated after 60 days of seed treatment in comparison to control. Dehydrogenase activity was significantly reduced to 63% after 15 days of quinalphos seed treatment in comparison to control in 1998. Similar trends were observed in 1999. A significant inhibition in dehydrogenase activity was observed after soil treatment both in 1998 and 1999. Phosphomonoesterase activities were significantly inhibited upto 25.2% as compared to the control, on the 15th day of chlorpyrifos seed treatment in 1998 and similarly, after one day of treatment in 1999. Quinalphos inhibited the phosphomonoesterase activity till the end of the experimental period in the soil treated fields, whereas recovered within 30-60 days of treatment in the seed treated fields. Arginine deaminase activity was significantly stimulated within one day after chlorpyrifos seed and soil treatments in both years. The activity was almost threefold higher on the 30th and the 15th day of soil treatment in 1998 and 1999, respectively. A temporary inhibition of arginine deaminase activity was observed after quinalphos treatment. It was observed that in most of cases insecticides have temporary inhibitory effect on soil enzymes. However, inhibition was smaller in seed treated soil than in direct soil treatment.     

Effect of five insecticides on microbial and enzymatic activities in sandy soil

Abstract

A laboratory study was conducted to examine the effects of five insecticides on microbial and enzymatic activities important to fertility in sandy soil. Cyfluthrin significantly increased bacterial populations after 2 wks. Imidacloprid showed an inhibitory effect on fungal numbers after 2 wks incubation while the others did not affect fungal population. No inhibitory effect was observed on nitrification of soil indigenous nitrogen. All treatments stimulated S‐oxidation after 4 wks. With the exception of cyfluthrin and imidacloprid after 2 wks, denitrification in sandy soil indicated that all treatment inhibited denitrification throughout the experiment. No inhibitory effects on biomass‐c were observed during 2‐wk periods. An inhibitory effect was observed on amylase after 1 wk while significant recovery was observed after 3 wks. With the exception of HgCl₂, no effect was observed on reducing sugar formation for 2 wks with all treatments. Formazan formation resulting from dehydrogenase activity was significantly greater with tebupirimphos and Aztec for 1 wk. All treatments supressed phosphatase activity for 1 wk, while none of the treatments suppressed phosphatase activity after 2 wks. Amitraz, tebupirimphos and Aztec inhibited urease activity for 1 wk. With the exception of tebupirimphos, no treatments affected N₂‐fixation in soil. Although short‐lived inhibitory effects on activities of microbes and enzymes were caused by the insecticides, the soil indigenous microbes can tolerate the chemicals used for control of soil pests.     

Effects of deltamethrin on hepatic microsomal cytochrome p450‐dependent monooxygenases in carp

Abstract The in vivo effects of sublethal concentrations of deltamethrin (DM), a pyrethroid insecticide, on the hepatic microsomal cytochrome P450 (Cyt P450) content and the Cyt P450‐dependent monooxygenase activities (para‐nitrophenetole‐O‐deethylase, pNPOD; aminopyrene‐N‐demethylase, APND; ethylmorphine‐N‐demethylase, EMND; 7‐ethoxycoumarin‐O‐deethylase, ECOD; and ethoxyresorufin‐O‐deethylase, EROD) were examined in adult carp (Cyprinus carpió L.).

0.2 μg/1 DM treatment resulted in significant increases in APND, EMND and ECOD activities, whereas 2 μg/1 DM resulted in significant inhibitions of all studied isoenzyme activities with the exceptions of pNPOD and APND after 72 h. EROD was the only enzyme for which a slight increase in activity was observed. On repeated treatment, Cyt P450 could not be detected after 48 h, but the Cyt P420 level increased. All tested isoenzyme activities were inhibited, with the exception ofthat of EROD, which was enhanced.

All these changes in enzyme activities and Cyt P450 content demonstrate the effects of DM on fish. DM treatment at low concentration is presumed to cause induction of the Cyt P450‐dependent monooxygenases which may lead to faster metabolization of the insecticide. In contrast, DM at higher concentration strongly inhibited the activities of the studied enzymes. This finding may be due to the damaging effect of DM on the xenobiotic metabolizing enzyme systems offish.     

Some toxicological aspects op methamidophos exposure in mice 1

Abstract

Cholinesterase activity in the brain, RBC and plasma of Swiss mice was determined following different routes of administration of methamidophos. Continuous feeding with the insecticide caused a progressive inhibition of both plasma‐ and erythrocyte enzymes. The effect of methamidophos was more pronounced when applied in diet than when administered dermally or intraperitoneally. Following a single injection (i.p.) of methamidophos, the brain enzyme showed maximum inhibition 24 hr following treatment. At the appearance of tremors, the plasma and RBC‐enzymes showed considerable inhibition, the former being more inhibited. The plasma enzyme appears to be the most sensitive enzyme and may be taken as a suitable index for exposure to methamidophos.     

Effects of metals on feeding rate and digestive enzymes in Gammarus fossarum: An in situ experiment

The feeding activity and afterward the assimilation of the products resulting of the food digestion, allow organisms to obtain energy useful for growth, maintenance and reproduction. These biological parameters may be studied to assess the impact of contaminants on the energy metabolism of organisms, which could induce potential effects at an individual level. The studied species was an amphipod Gammarus fossarum, which has a high ecological relevance since it is widespread in European streams and plays a major role in the breakdown of leaf litter. Thus some G. fossarum were transplanted in four sites of a river characterized by metal contamination (Amous River, France). The following parameters were studied: digestive enzymes activities (esterase, β-glucosidase, β-galactosidase, amylase and endoglucanase), feeding rate, metal bioaccumulation and survival. Results showed a strong relationship between digestive enzymes activities, feeding rate and metal contents.     

Effect of some xenobiotics on kynurenine hydrolase and kynurenine aminotransferase of mouse liver

Abstract

The effects of some xenobiotics on the activity of the B₆‐dependent kynurenine hydrolase (KH) and kynurenine aminotransferase (KATE) in mouse liver, were investigated. Polychlorinated biphenyl (Aroclor 1254) (400mg/kg/day ×4) markedly decreased the activity of both enzymes. Benzo(a)pyrene (BP) and 3‐methylcholanthrene (3‐MC) (40mg/Kg/day ×1) as well as phénobarbital (PB) (75mg/kg/day ×3) did not alter the activity of KH, while that of KATE was mildy reduced. The response of the two enzymes to treatment with chlorpromazine (CPZ) (5mg/Kg/day ×5) were opposite with marked elevation of KH and inhibition of KATE activities. Treatment with B‐naphthoflavone (B‐NF) (80mg/Kg/day ×2), Pyrazole (200mg/Kg/day ×1) or indole (400mg/kg/day ×1) produce no change in the activity of either enzyme. It, seems therefore, that Aroclor(1254) and chlorpromazine may cause disordered kynurenine metabolism through alterations in the activities of its metabolizing enzymes. This, in turn, might affect nicotinamide adenine dinucleotide biosynthesis and/or the accumulation of some tryptophan metabolites suspected of being carcinogenic or co‐carcinogenic.