Effect of endosulfan and parathion on energy reserves and physiological parameters of the terrestrial isopod Porcellio dilatatus

The in vivo effects of parathion and endosulfan on the isopod Porcellio dilatatus were investigated. Feeding parameters (food consumption and assimilation rates), growth, and energy reserves (glycogen, lipid, and protein contents) of pesticide-exposed isopods were compared with those of control animals. Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, and 500 microg/g of food) for 21 days. The route of uptake of the pesticides was through the diet (alder leaves). Results revealed that parathion induces a significant depression of glycogen, lipid, and protein contents. However, no significant effect was observed on either feeding parameters or growth. Animals fed endosulfan-contaminated food had smaller amounts of glycogen and lipid than control animals, while protein levels were similar in all treatments. Endosulfan also induced a significant decrease in food consumption and assimilation rates at the highest concentrations tested. Growth rate was also significantly affected by endosulfan. These results suggest that the isopod P. dilatatus is a suitable species for use in toxicity tests and that energy reserves could be used as effect criteria in both laboratory and field studies.     

Influence of dimethoate on acetylcholinesterase activity and locomotor function in terrestrial isopods

Locomotor behavior in terrestrial organisms is crucial for burrowing, avoiding predators, food seeking, migration, and reproduction; therefore, it is a parameter with ecological relevance. Acetylcholinesterase (AChE) is a nervous system enzyme inhibited by several compounds and widely used as an exposure biomarker in several organisms. Moreover, changes in energy reserves also may indicate an exposure to a stress situation. The aim of this study is to link biomarkers of different levels of biological organization in isopods exposed to increasing doses of dimethoate in semifield conditions. Locomotor parameters, AChE activity, and energy reserves (lipid, glycogen, and protein contents) were evaluated in the isopod Porcellio dilatatus after 48-h and 10-d exposure to dimethoate-contaminated soil. Results showed a clear impairment of both locomotor and AChE activity during the entire study, although effects were more pronounced after 48 h. Most locomotor parameters and AChE activity showed a clear dose-response relationship. By contrast, no clear trend was observed on energetic components. A positive and significant relationship was found between AChE activity and those locomotor parameters indicating activity, and the opposite was observed with those locomotor parameters indicating confusion and disorientation. The results obtained in this study enhance the importance of linking biochemical responses to parameters with ecological relevance at individual level, the value of locomotor behavior as an important marker to assess effects of toxicants, and also the usefulness and the acquisition of ecological relevance by AChE as a biomarker, by linking it with ecologically relevant behavioral parameters.     

Optimization of culture conditions of Porcellio dilatatus (Crustacea: Isopoda) for laboratory test development

This paper describes the experimental results for optimizing isopod culture conditions for terrestrial ecotoxicity testing. The influence of animal density and food quality on growth and reproduction of Porcellio dilatatus was investigated. Results indicate that density influences isopod performance in a significant way, with low-density cultures having a higher growth rate and better reproductive output than medium- or high-density cultures. Alder leaves, as a soft nitrogen-rich species, were found to be the best-quality diet; when compared with two other food mixtures, alder leaves induced the best results, particularly in terms of breeding success. Guidance regarding culture conditions of isopod species, especially in terms of culture density and diet, is given.     

Optimization of Culture Conditions of Porcellio dilatatus (Crustacea: Isopoda) for Laboratory Test Development

This paper describes the experimental results for optimizing isopod culture conditions for terrestrial ecotoxicity testing. The influence of animal density and food quality on growth and reproduction of Porcellio dilatatus was investigated. Results indicate that density influences isopod performance in a significant way, with low-density cultures having a higher growth rate and better reproductive output than medium- or high-density cultures. Alder leaves, as a soft nitrogen-rich species, were found to be the best-quality diet; when compared with two other food mixtures, alder leaves induced the best results, particularly in terms of breeding success. Guidance regarding culture conditions of isopod species, especially in terms of culture density and diet, is given.     

Tubifex: a sensitive model for UV-B-induced phototoxicity

The natural increase of UV-B radiation levels due to depletion of the ozone layer in the atmosphere may impose additional stress for the survival of zooplanktons which serve as a major constituent of the aquatic food chain. To study the adverse effects of UV-B radiation on the aquatic biomass, studies were conducted using the aquatic organism Tubifex as a model, as UV-B radiation is known to penetrate into the natural waters. UV-B radiation induced mortality in tubifex and the production of activated oxygen species by these organisms. Alterations in DNA, RNA, protein, glutathione (GSH), hydrogen peroxide H(2)O(2), thiobarbituric acid-reactive substance (TBA-RS), ATPase, AChE, GST, and LDH activities in Tubifex at various doses (0-2.0 J) of UV-B radiation were found. LC(50) value for UV-B-induced mortality of Tubifex was 0.80+/-0.15 J and the threshold dose was 0.35+/-0.05 J; mortality began within 3h postirradiation. UV-B dose-dependent production of singlet oxygen, superoxide anion, and hydroxyl radicals by Tubifex was observed. DNA, RNA, protein, and GSH contents were found to decrease significantly (P<0.001) while H(2)O(2) and TBA-RS increased (P<0.01) under the influence of UV-B radiation. The activities of ATpase, AChE, and GST enzymes were inhibited (P<0.01) and LDH activity was significantly increased (P<0.001) in Tubifex exposed to UV-B radiation. The results suggest that an increase in UV-B radiation alters several biochemical processes, leading to the mortality of the organism. Tubifex could be useful as a sensitive alternate model for studying UV-B-induced phototoxicity and possible mechanisms of action.     

Effects of salinity on biomarker responses in Crassostrea rhizophorae (Mollusca, Bivalvia) exposed to diesel oil

Crassostrea rhizophorae is a euryhaline oyster that inhabits mangrove areas, which are widely distributed along the Brazilian coast. The aim of this study was to investigate the effects of salinity (9, 15, 25, and 35ppt) on the activities of glutathione S-transferase (GST), glucose 6-phosphate dehydrogenase (G6PDH), catalase (CAT), and acetylcholinesterase (AChE) in the digestive gland of this species after exposure to diesel oil for 7 days at nominal concentrations of 0.01, 0.1, and 1mlL(-1) and after depuration for 24h and 7 days. GST activity increased in a diesel oil concentration-dependent manner at salinities 25 and 15ppt and remained slightly elevated even after depuration periods of 24h and 7 days. No changes were observed in the activities of G6PDH, CAT, and AChE in the oysters exposed to diesel and depurated. Based on these results, GST activity in the digestive gland of C. rhizophorae might be used as a biomarker of exposure to diesel oil in sites where the salinity is between 15 and 25ppt, values usually observed in mangrove ecosystems.     

A comparison of the effects of single and repeated exposure to an organophosphate insecticide on acetylcholinesterase activity in mammals

Exposure to organophosphate (OP) pesticides can occur in free-living mammals in treated areas. Risk to nontarget animals from OPs usually is assessed with acute exposure data, but exposure of wild animals is likely to be intermittent and chronic. We compared the effects of single or repeated (hourly and daily) exposure to dimethoate on acetylcholinesterase (AChE) activity in laboratory mice to assess the suitability of standard laboratory tests for assessing risk. Mice were exposed either to a single dose (10 or 30 mg/kg) or to short-term repeated (three hourly doses of 10 mg/kg) intraperitoneal doses of dimethoate, and brain and serum AChE activity were measured. No significant difference was found in the degree of inhibition of AChE activity following acute and short-term repeated exposure. In a second experiment, mice were given three daily doses of 10 or 20 mg/kg of dimethoate, and both AChE activity and hepatic cytochrome P450 enzyme activity were measured. Daily exposure resulted in a dose-dependent decline in brain and serum AChE activity, and inhibition increased progressively with successively repeated exposures. However, this effect was relatively small compared to the effect of dose. Cytochrome P450 enzyme activity (CYP2B) was inhibited in the dimethoate-dosed mice. Our results indicate that acute dose-response toxicity studies are suitable models for predicting the likely occurrence of adverse effects from either short- or longer-term exposure of wild mammals to anticholinesterase compounds. Likely differences in exposure pattern between the laboratory and the natural environment are unlikely to bias the predictive power of these studies significantly.     

Use of two biomarkers (CYP450 and acetylcholinesterase) in zebra mussel for the biomonitoring of Lake Maggiore (northern Italy)

The use of zebra mussel Dreissena polymorpha as a bioaccumulator for lipophilic compounds is nowadays standardized, but its employment in early warning systems by the biomarker approach is much less frequent. One of the main problems with the biomarker approach is due to natural variation of abiotic factors such as temperature that influence the activity of several enzymes. In this study, we investigated the influence of this environmental parameter on the activities of two different biomarkers: acetylcholinesterase (AChE) (inhibited by organophosphorus compounds) and CYP450 (inversely influenced by planar compounds and heavy metals). We used these two biomarkers to evaluate the environmental pollution of Lake Maggiore (northern Italy). Results showed a strong AChE inhibition in mussel specimens collected in some sampling sites of the lake, indicating heavy pollution by neurotoxic compounds. We also found a twofold effect on CYP450 activity, probably due to the activating effect of planar compounds and the inhibiting effect of trace metals.     

Influence of dietary selenium supplementation and exercise on thiol-containing enzymes in mice

OBJECTIVE: Exercise markedly increases oxygen uptake by active muscles and consequently increases generation of reactive oxygen species. A dietary deficiency in selenium (Se) can increase the sensitivity of the living system to oxidative stress. delta-Aminolevulinate dehydratase (delta-ALA-D), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) are sulfhydryl-containing enzymes, and their activities are sensitive to the presence of oxidizing agents. We investigated the effect of Se deficiency and supplementation on delta-ALA-D, SDH, and LDH activities in mice subjected to swim training for 8 wk. METHODS: Three-month-old female mice were randomly assigned and fed a basal diet, a basal diet plus 1 ppm of Se, and a basal diet plus 40 ppm of Se. These groups were further divided into sedentary and swim-trained groups. A mass equivalent of 5% of the animal's body weight was fixed to the tail. Animals were then exercised for 60 min/d, 4 d/wk. RESULTS: Swim-training associated with Se-deficient diet diminished delta-ALA-D activity in the livers and kidneys. SDH activity was diminished in the skeletal and cardiac muscles of this group. CONCLUSIONS: These results indicated that exercise associated with dietary Se deficiency can inhibit the production of thiol-containing enzymes, delta-ALA-D and SDH, from different tissues; however, LDH activity was not changed. The decrease in enzyme activities can be tentatively attributed to oxidation of thiol groups by the reactive oxygen species produced by exercise.     

Alterations on AChE activity of the fish Anguilla anguilla as response to herbicide-contaminated water

The inhibition of both total and specific acetylcholinesterase activities was measured in the whole eyes of the yellow eel Anguilla anguilla after exposure to the carbamate thiobencarb. In vivo assays were conducted under a constant flow-through system of thiobencarb-contaminated water (1/60 LC(50) 96 h=0.22 ppm for 96 h) followed by a recovery period in clean water (192 h more). The results indicated a measurable level of AChE activity on eyes of control eels, which resulted in a sensitive indicator of the presence of thiobencarb in the water. The pesticide induced significant inhibitory effects on AChE activity ranging from 35% in total AChE activity to 75% in specific AChE activity. Following 1 week of recovery, AChE activity in eel eyes was still different from that of controls. Specific AChE activity remained significantly depressed (35%). On the other hand, protein content in whole eyes of pesticide-treated eels did not exhibit any significant difference from control animals. It has been accepted that a minimum of 20% reduction in brain AChE would be necessary to be indicative of exposure to anticholinergic agents; however, few data are reported about this effect on sense organs.     

Effects of endosulfan on brain acetylcholinesterase activity in juvenile bluegill sunfish

The effects of endosulfan upon brain acetylcholinesterase (AChE) activity were measured in juvenile bluegill sunfish (Lepomis macrochirus). Based on exposure durations of 0, 24, 48, 72, and 96h and 1 week at 1.0 microg/L (just below the LC50 of 1.2 microg/L for this species), step-wise decreases in AChE activity were noted, corresponding to 0%, 3.57%, 12.65%, 14.23%, 16.31%, and 23.11% inhibition, respectively. Total brain protein concentrations were measured to test the accuracy of the AChE data with no significant anomalies. The duration of exposure was related to the reduction in the AChE activities which reflected the biotoxicity of endosulfan. The changes in the AChE activities will certainly affect the normal behavior of the juvenile bluegill which is detrimental to their very existence in the natural habitat.     

急性一氧化碳中毒患者血清酶活力的动态变化

目的探讨血清酶变化在急性一氧化碳(CO)中毒中的临床意义.方法检测62例急性CO中毒患者血清酶活力及心电图(ECG),并进行动态观察.结果急性CO中毒者5种血清心肌酶活力在中毒后24h开始增高,天冬氨酸转氨酶(AST)、肌酸磷酸激酶(CPK)、乳酸脱氢酶(LDH)、α-羟丁酸脱氢酶(α-HBDH)、肌酸激酶同工酶(CK-MB)活力分别为(20.2±12.3)、(151.6±91.8)、(146.8±50.4)、(154.8±47.7)、(13.8±8.1)U/L,对照组分别为(12.1±6.7)、(90.6±17.3)、(118.7±13.5)、(89.9±27.9)、(5.9±3.3)U/L,两组的差异均有显著性(P＜0.01);3 d后分别为(21.3±12.3)、(105.8±51.4)、(144.8±51.4)、(159.8±35.4)、(16.2±9.1)U/L;7、12 d后α-HBDH和CK-MB活力仍较对照组增高,差异均有显著性(P＜0.01).乳酸脱氢酶同工酶1(LDH1)、乳酸脱氢酶同工酶2(LDH2)活力中毒后24h内增高,并达峰值,分别为(35.3±5.8)、(43.8±5.7)U/L,3 d时LDH1、LDH2和7 d时LDH1与对照组的差异均有显著性(P＜0.01).轻、中度中毒组同期比较,7 d时LDH1与12 d时的差异有显著性(P＜0.01).LDH1血清酶检查异常率最高达78.7%,LDH2为58.3%,LDH为45.2%,CK-MB为37.1%,α-HBDH为33.6%.ECG检查异常率＜10%.结论CO中毒可引起心肌损害,血清酶活力检测可提示心肌损害,有助于此种损害的的早期诊治、疗效观察及预后判断.     

德国小蠊乙酰胆碱酯酶活性的体躯分布和亚细胞分布

目的了解德国小蠊乙酰胆碱酯酶（AChE）活性的体躯分布和亚细胞分布。方法利用不同体躯和不同亚细胞的AChE活性进行测定。结果德国小蠊雄成虫的AChE在头部、胸部及腹部的活性分别占总活性的56.9%、19.5%和23.6%。德国小蠊的AChE在头、胸、腹间的活性分布差异有统计学意义（F=127.96,P〈0.05）,头部AChE的活性显著高于胸部和腹部（P〈0.001）,德国小蠊亚细胞AChE的总活性和比活力按大小排列依次为：线粒体〉微粒体〉胞质溶液〉细胞核及细胞碎片。结论德国小蠊的AChE在头部、胸部、腹部均有分布,但头部活性最高,占整体活性的50%以上。亚细胞分布显示德国小蠊AChE在线粒体里分布最多,约占总活性的50%。     

Effects of carbofuran on the sea bass (Dicentrarchus labrax L.): study of biomarkers and behaviour alterations

The objective of this study was to investigate the acute effects of the pesticide carbofuran on the sea bass (Dicentrarchus labrax) using parameters at different levels of biological organisation (swimming behaviour and several biomarkers) and possible relationships between alterations found in different effect criteria. In a bioassay, sea bass juveniles were individually exposed to different doses of carbofuran (31, 63, 125 and 250 μg/L) for 96 h. At the end of the bioassay, the swimming performance and 11 biomarkers were determined. Biomarkers were: hepatosomatic index (HSI), lipid peroxidation (LPO), reduced glutathione and the activities of the enzymes ethoxyresorufin O-deethylase (EROD), glutathione S-transferases, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, brain acetylcholinesterase (AChE) and muscle cholinesterases (ChE). After 96 h of exposure, carbofuran induced a decrease of the swimming velocity and inhibition of EROD activity at all concentrations tested, and inhibition of muscle ChE and brain AChE activities at 250 μg/L. No relevant alterations in any of the other tested parameters were found. These results show that carbofuran induced adverse effects on fish by interfering with neurofunction, capability of detoxication and swimming velocity. In addition, positive and significant correlations between the swimming velocity and (i) brain AChE activity, (ii) muscle ChE activity and (iii) EROD activity suggest that the inhibition of these enzymes may somehow be related to the behavioural changes observed. Since these functions are determinant for the survival and performance of the fish in the wild, the findings of the present study suggest that adverse effects may occur in populations exposed to carbofuran if a sufficient number of animals is affected.     

An in vivo and in vitro study of erythrocyte membrane acetylcholinesterase, (Na+, K+)-ATPase and Mg2+-ATPase activities in basketball players on alpha-tocopherol supplementation. The role of L-carnitine

BACKGROUND & AIMS: Vitamin E (alpha-tocopherol, alpha-Te) and carnitine reduce lipid peroxidation. THE AIM WAS TO: To investigate the erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities in basketball players with or without alpha-Te supplementation, before and after training. In vitro, we aimed to find out any additional effect of L-carnitine (L-C) on the modulated enzyme activities. SUBJECTS AND METHODS: Blood was obtained from 10 players before (group A), after exercise (group B) and after 1 month on alpha-Te (200 mg/24 h orally) supplementation before (group C) and after the game (group D). Lactate, pyruvate, muscle enzyme activities and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and alpha-Te were determined with HPLC methods and membrane enzyme activities spectrophotometrically. RESULTS: Lactate, pyruvate, muscle enzymes and catecholamine levels were increased (P<0.001) in all groups after training. Alpha-Te levels and Mg2+-ATPase activity remained unaltered before and after exercise. TAS was decreased in the groups after the game. AChE activity was increased in group B (P<0.01) and decreased in group D (P<0.01). After the exercise, Na+, K+-ATPase activity was increased in group B and remained unaltered in group D. In vitro incubation of membranes from group D with L-C resulted in a partially restoration of the membrane AChE activity, whereas Na+, K+-ATPase and Mg2+-ATPase activities were found unchanged. CONCLUSIONS: Alpha-Te supplementation in basketball players results in an increase of TAS and AChE activity, whereas the other enzyme activities were found unchanged. L-C addition may restore AChE activity, which was modulated by training in players on alpha-Te.     

Sublethal Effects of Three Pesticides on Activities of Selected Target and Detoxification Enzymes in the Aquatic Midge, Chironomus tentans (Diptera: Chironomidae)

Sublethal effects of three pesticides including atrazine (triazine herbicide), DDT (organochlorinated insecticide), and chlorpyrifos (organophosphate insecticide) on acetylcholinesterase (AChE), general esterase (GE), glutathione S-transferase (GST), and cytochrome P450 monooxygenase (P450) activities were evaluated in the aquatic midge Chironomus tentans. Exposures of midges to atrazine at 30 and 150 micrograms per liter (μg/L) for 20 d (i.e., from the first- to fourth-instar larvae) enhanced P450 O-deethylation activity by 12.5- and 15.5-fold, respectively, but did not significantly change AChE, GST, and GE activities. Similar exposures to DDT at 0.01 and 0.05 μg/L did not significantly affect AChE, GE, and P450 activities; however, DDT at 0.05 μg/L enhanced GST activity toward the substrate 1-chloro-2, 4-dinitrobenzene by 33.6%. Exposures of midges to chlorpyrifos at 0.10 μg/L for 20 d reduced AChE activity by 59.8%, and GE activities toward the substrates α-naphthyl acetate and β-naphthyl acetate by 30.7 and 48.8%, respectively. The reduced GE activities appear to be due to the inhibition of several esterases, particularly the one with a slow migration, by chlorpyrifos as demonstrated by non-denaturing polyacrylamide gel electrophoresis. Furthermore, exposure of midges to chlorpyrifos at 0.10 μg/L for 20 d enhanced the P450 O-deethylation activity by 3.3-fold although no significant effect was observed at 0.02 μg/L for the same enzyme. These results provide insights into the sublethal effects of these commonly detected pesticides in aquatic environments on important enzymes in aquatic midges.     

Acute Toxicity and Acetylcholinesterase Inhibition in Grass Shrimp (<Emphasis Type="Italic">Palaemonetes pugio</Emphasis>) and Oysters (<Emphasis Type="Italic">Crassostrea virginica</Emphasis>) Exposed to the Organophosphate Dichlorvos: Laboratory and Field Studies

The use of various organophosphates to control mosquito populations is a common practice across the globe. We review the literature (LC50s) on dichlorvos, the primary breakdown product of Dibrom, and use laboratory and field experiments to determine the lethal and sublethal (bioassays) effects of dichlorvos on two widely distributed and ecologically important estuarine invertebrate species, the marsh grass shrimp, Palaemonetes pugio and the Eastern oyster, Crassostrea virginica. Laboratory results based on LC50s and sublethal acetylcholinesterase (AChE) inhibition activity bioassays indicate that adult grass shrimp are more sensitive (approximately 500 x ) to dichlorvos than juvenile oysters. Although potentially an important factor for intertidal or shallow-dwelling estuarine organisms, the toxicity of dichlorvos was not enhanced in the presence of simulated sunlight for adult P. pugio. The most notable decreases in AChE activity were for grass shrimp and oysters exposed to dichlorvos concentrations above those considered ecologically relevant. In field experiments, both species were deployed in cages in unsprayed (n = 2) and sprayed (n = 3) sites and water samples collected pre- and post-spraying. Quantifiable dichlorvos levels were measured at the two narrowest creek treatment sites following mosquito spraying, suggesting that overspray can occur and there was evidence of a sublethal AChE response at these same sites. However, experiments at the widest creek revealed no measurable dichlorvos or sublethal responses. Results from this research suggest that adult grass shrimp are more sensitive to dichlorvos than juvenile oysters. Spraying near small tidal creeks may have measurable impacts on resident species, while larger (wider) creeks appear to be capable of buffering organisms from transient fluxes of mosquito control agents that may enter the system.     

性别分化关键期三丁基氯化锡暴露对大鼠生精功能和睾丸酶活力的影响

目的 探讨性别分化关键期三丁基氯化锡(TBTC)暴露对大鼠性成熟后睾丸酶活力和生精功能的影响.方法 将16只健康成年SPF级妊娠Wistar大鼠随机分为高(5.0 mg/kg)、中(2.5mg/kg)、低剂量(1.0 mg/kg)TBTC染毒组和溶剂对照组(玉米油),每组4只.从妊娠第12天起,采用经口灌胃方式进行染毒,每天1次,直至妊娠第20天,灌胃剂量为5.0ml/kg.出生后第70天,每组随机抽取10只雄性仔鼠,称重后处死,分离双侧睾丸及附睾组织,测定附睾精子数及睾丸酶[乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、酸性磷酸酶(ACP)、一氧化氮合酶(NOS)]活力.结果 与溶剂对照组比较,各TBTC染毒组孕鼠妊娠第12天及第20天的体重和体重增长量差异无统计学意义(P>0.05).与溶剂对照组比较,高、中剂量TBTC染毒组雄性仔鼠断乳后体重增长较慢,差异均有统计学意义(P<0.01). TBTC染毒组附睾尾精子数随TBTC染毒剂量的升高呈上升趋势,差异有统计学意义(P<0.01).与溶剂对照组相比,高、中、低剂量TBTC染毒组雄性仔鼠LDH活力较高,高、中剂量TBTC染毒组雄性仔鼠SDH活力较高,差异均有统计学意义(P<0.01).各TBTC染毒组雄性仔鼠ACP和NOS活力间比较,差异均无统计学意义(P＞0.05).未发现睾丸组织结构发生改变.结论 性别分化关键期TBTC染毒对雄性仔鼠具有内分泌干扰作用,减缓了雄性仔鼠的体重增长,促进了其精子发生和LDH、SDH的活力.

Abstract：

Objective To explore the effects of exposure to tributyltin chloride (TBTC)during the critical period for sex differentiation on activities of enzymes in testis and spermatogenesis function in Wistar rats.Methods Sixteen healthy adult pregnant Wistar rats were randomly divided into four groups(5,2.5 and 1 mg/kg TBTC,vehicle control)with 4 animals per dose group.They were given doses of TBTC by gavage from days 12-20 of gestation once a day.The volume of the vehicle used was 5 ml/kg body weight.On the postnatal day (PND)70,ten male offsping rats were randomly selected in each group and sacrificed by decapitation after weighed.The sperms in epididymis were counted and the activities of enzymes of testis[including lactate dehydrogenase (LDH),succinate dehydrogenase (SDH),acid phosphatase (ACP),nitric oxide synthase (NOS)]were detected.Several testises were chosen for the histopathological examination.Results The body weight gains of pregnant rats from days 12-20 showed no significant difference among the solvent control group and the each TBTC exposure group (P>0.05).Compared with the control group,body weights gains from PND21-70 were decreased significantly in the 5 and 2.5 mg/kg group (P＜0.01).Cauda epididymal sperm counts increased with the increase of TBTC doses (P<0.01).The activities of LDH in all treated groups and the activities of SDH in the 5 and 2.5 mg/kg TBTC group exhibited significant increase compared with the control group (P＜0.01).There were no significant difference in the activities of ACP and NOS between the exposure groups and the control group(P>0.05).No abnormal structure of testis was observed in all exposure groups.Conclusion Exposure to TBTC during critical period for sex differentiation may decrease body gain and increase spermatogenesis and the activities of LDH and SDH.     

Effects of hepatotoxicants on the induction of microsomal monooxygenase activity in sunfish liver by beta-naphthoflavone and benzo[a]pyrene.

Effects of chemically induced hepatic injury on biotransformation enzymes in fish were studied. Sunfish hybrids (Lepomis macrochirus x L. cyanellus) were dosed per os with allyl formate (ALF) and carbon tetrachloride (CCl4), and the induction of liver EROD (7-ethoxyresorufin O-deethylase) activity was subsequently challenged by injections of beta-naphthoflavone (BNF) and benzo[a]pyrene (B[a]P). Hepatotoxicity of chemical treatments was assessed using blood enzymes (ASAT, ALAT, and LDH) along with other biochemical variables. Both hepatotoxicants partially abolished the induction of EROD (maximally by 76-89%), and the decrease in induction was dose related. The cytosolic activity of glutathione S-transferase (GST) in the liver decreased in parallel with the decrease in EROD induction. Fish receiving high doses of ALF exhibited significantly less microsomal and blood plasma proteins and, occasionally, were jaundiced. These symptoms, however, were less sensitive indicators of hepatotoxicity than alterations in liver EROD and GST. Both ALF and CCl4 increased the activities of hepatic enzymes in the blood plasma, indicating cytotoxicity. In addition B[a]P, unlike BNF, also increased plasma activities of LDH and ALAT at a dose inducing liver EROD, implying simultaneous hepatotoxicity at high sublethal levels of this xenobiotic. These data suggest that hepatotoxic chemicals absorbed by fish may act antagonistically by decreasing the degree of induction of the cytochrome P450 system relative to the inherent capacity of inducing xenobiotic chemicals present in the environment. Therefore, when assessing the toxicological status of water using fish health biomarkers, it is advisable to measure a concert of metabolic and biochemical variables instead of any single biomarker.     

Influence of physical exercise and gender on acetylcholinesterase and butyrylcholinesterase activity in human blood samples

The determination of cholinesterase activity in plasma and erythrocytes serves as a useful and sensitive biomarker of exposure to organophosphorus and carbamate pesticides. However, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity may be influenced by factors such as age, gender, drugs, and physical exercise. The aim of this study was to evaluate the effects of gender and physical exercise on the activity of AChE and BuChE in healthy individuals. The values for both enzymes were lower for women. Physical exercise increased the levels of BuChE, and had no significant effect on AChE. To our knowledge, this is the first clinical study evaluating the influence of physical exercise in levels of these enzymes. Considering that cholinesterase activity is a useful parameter in assessing the exposure of individuals to pesticides, it is important to understand factors that influence the determination of the enzymes in order to avoid the erroneous interpretation of results.