溴化1-己基-3-甲基咪唑对斜生栅藻谷胱甘肽及其代谢酶的影响

研究了浓度为0、1、5、10、15、20 mg/L的新兴离子液体溴化1-己基-3-甲基咪唑([C6mim]Br)在24h、48h、72h和96h对斜生栅藻还原型谷胱甘肽（GSH）及其代谢酶-谷胱甘肽过氧化物酶（GPX）、谷胱甘肽转硫酶（GST）和谷胱甘肽还原酶（GR）的影响。结果表明：GSH含量在24h、48h和72h时,在最低处理浓度下不变,其他处理浓度下随胁迫浓度增加而降低,96h时则与对照无差异或较小;GPX和GST的活性在72h之前明显升高（最高浓度组的GST活性有波动）,96h时均降低至对照水平;GR活性在24h时,[C6mim]Br=1 mg/L时升高,之后降低,在48h增高至对照水平,72h时,[C6mim]Br≥10 mg/L的处理组高于对照水平,96h时,除最低处理组外,均降至对照水平以下。GR是GSH系统中的限速酶,GST则是该系统中活性和灵敏性最高的酶,可作为[C6mim]Br胁迫时的敏感的生物标志物。1 mg/L的[C6mim]Br可引起藻细胞的氧化胁迫,具有环境毒性。     

高效氯氟氰菊酯对大鳞副泥鳅急性毒性和生理毒性的影响

为了估测高效氯氟氰菊酯对水生生物毒性的大小,以大鳞副泥鳅作为受试动物,研究不同浓度的高效氯氟氰菊酯对其急性毒性和生理毒性的影响。结果表明:高效氯氟氰菊酯对大鳞副泥鳅24h、48h、96h的半数致死浓度(LC50)分别为25.93μg/L、17.28μg/L、14.11μg/L,安全浓度为2.30μg/L。低浓度高效氯氟氰菊酯对大鳞副泥鳅肝脏谷丙转氨酶(GPT)和谷草转氨酶(GOT)起诱导作用,高浓度对其起抑制作用,试验组与对照组存在显著或极显著差异。研究表明,高效氯氟氰菊酯对大鳞副泥鳅有较强的毒性。     

三油酸酯-半渗透膜采样装置对有机氯农药的富集作用

在实验室流水条件下研究了林丹、艾氏剂、环氧七氯、4 ,4′ 滴滴涕及六氯苯在三油酸酯 半渗透膜采样器 (SP MDs)中的富集。所研究的 5种有机氯农药在SPMDs中富集迅速 ,动力学过程可以用线性关系描述 ,2 0d后富集系数达到 15 0 0— 180 0 0。当暴露于接近天然水体浓度时 (2 μg/L) ,富集量能够达到对生物标记物研究制样量的要求 ,富集量大小顺序为六氯苯 >4 ,4’ 滴滴涕 >七氯环氧 >艾氏剂 >林丹 ,与有机氯化合物的脂 /水分配系数成正相关。初步研究结果表明SPMDs可以用来作为生物标记物测试的样品前处理手段 ,或替代水体生物进行微量或痕量有毒有机污染物的生物毒性监测。     

大豆荚壳杀根结线虫成分的分离及其对抗氧化酶活性的影响

采用液-液分配萃取方法,从大豆荚壳甲醇提取物中分离获得石油醚、氯仿、乙酸乙酯、正丁醇和水的萃取物,测定了其对南方根结线虫J2的毒杀活性,结果表明正丁醇萃取物比其它4种萃取物有更高的杀虫活性,24和48 h对线虫校正死亡率分别为57.76%和67.72%.将正丁醇萃取物通过硅胶柱层析和薄层层析,得到8个组分,通过杀虫活性试验,得到组分2和7为主要的杀虫活性组分,24和48 h对线虫校正死亡率分别为65.93%、66.65%和69.25%、68.51%.进一步就组分2和7对J2抗氧化酶活性的影响进行了研究,结果表明两种组分对谷胱甘肽转硫酶和过氧化氢酶活性都有一定的抑制作用,其中两种组分对过氧化氢酶活性的抑制效果差异不显著,组分7对谷胱甘肽转硫酶活性具有显著的抑制效果,24和48 h的抑制率分别可达72.36%和50.21%.说明大豆荚壳的杀线虫活性成分可能通过影响虫体内的氧化代谢,使线虫体内氧化和抗氧化作用失衡,最终导致线虫死亡.     

两种新型农药对斜生栅藻（Scenedesmus obliquus Kuetz．）的毒性研究

LY-04和WSQIF是由华中师范大学农药所合成的两种新型有机磷农药,LY—04属于α-氧代膦酸衍生物,WSQIF属于芳氧基乙酰氧基烃基膦酸脂。选用斜生栅藻(Scenedesmus obliquus Kuetz．)作为实验生物,通过显微计数测定藻细胞的密度以计算LY—04和WSQIF对斜生栅藻24h、48h、72h、96h的半效应抑制浓度(EC50),研究其对斜生栅藻的毒性效应。结果表明：以丙酮为溶剂时,每隔24h取样,测得LY—04对斜生栅藻的48h、72h、96h的ECs。值分别为2942．5mg／L、239．7mg／L和65．0mg／L,而WSQIF的24h、48h、72h、96h的EC5。值分别为15．9mg／L、53．0mg／L、98．0mg／L和28．8mg／L。LY—04和WSQIF分别作为杀虫剂和除草剂而研制,经活体研究表明,LY—04具有较强的杀虫活性,WSQIF则具有很强的除草活性,所得EC50。值基本符合设计结果。根据毒性分级标准,LY—04和WSQIF的EC50。值远大于3mg／L,其对非靶生物中的水生藻类都属于低毒,可推广应用。     

三种常见品牌护肤品暴露对鲮肝脏SOD和GST活性、GSH含量的影响

研究护肤品暴露对鲮(Cirrhinus molitorella)的毒性效应,为护肤品的安全使用和污染控制提供科学依据。配置不同浓度(0 g·L^-1、0.5 g·L^-1、0.75 g·L^-1、1.00 g·L^-1)的护肤品暴露鲮48h,在暴露时间为0、6 h、12 h、24 h、36 h、48 h时,测定鲮肝脏中超氧化物歧化酶(SOD)活性、谷胱甘肽转移酶(GST)活性、谷肮甘肽过氧化物酶(GSH)含量,观察并记录鲮的死亡情况,计算三种护肤品对鲮的半致死浓度(LC50)。结果表明:三种护肤品的暴露浓度为1.00 g·L^-1时,SOD酶和GST酶活性达到最大;三种酶活性都是随着时间的增加呈现先增后减的变化规律;护肤品B、C暴露48h时,GSH酶被抑制;护肤品A、B、C 48h的LC50分别为807 mg·L^-1、973 mg·L^-1和1147 mg·L^-1。护肤品A、护肤品B和护肤品C的毒性分别为中毒物质,中毒物质和低毒物质,中高价位的护肤品对鲮的伤害相对较小。     

甜菜夜蛾抗氯氟氰菊酯品系相对适合度、抗性生化机理及抗性遗传方式

比较了甜菜夜蛾Spodoptera exigua 抗氯氟氰菊酯品系和敏感品系的繁殖和生长发育特征。结果表明：抗性品系幼虫发育历期延长、蛹重减轻、化蛹率和产卵量降低,抗性品系的适合度为0.61,抗性品系在繁殖和生长发育上存在明显的生存劣势。用两品系3龄幼虫分别测定胡椒基丁醚（PBO）、增效磷SV₁）、脱叶磷（DEF）和顺丁烯二酸二乙酯（DEM）对氯氟氰菊酯的增效作用,抗性品系增效倍数与敏感品系增效倍数之比分别为14.1、14.8、2.3和2.3倍,胡椒基丁醚和增效磷对氯氟氰菊酯增效作用最明显,表明多功能氧化酶参与了甜菜夜蛾对氯氟氰菊酯的抗性。抗性品系3龄幼虫酯酶和谷胱甘肽S-转移酶的活性分别为敏感品系的1.05倍和0.91倍, 抗性品系5龄幼虫多功能氧化酶O-脱甲基活性为敏感品系的1.05倍,两品系间3种酶的活性差异不显著,表明甜菜夜蛾对氯氟氰菊酯的抗性与酯酶、谷胱甘肽S-转移酶及多功能氧化酶O-脱甲基酶活性无关。用剂量对数死亡机率值回归线分析法研究甜菜夜蛾对氯氟氰菊酯的抗性遗传规律,表明甜菜夜蛾对氯氟氰菊酯的抗性为常染色体遗传、多基因控制;正、反交后代的显性度分别为0.61和0.43,抗性遗传为不完全显性。     

8%高效氯氟氰菊酯微乳剂对环境生物的安全性评价

高效氯氟氰菊酯是一种拟除虫菊酯类杀虫剂,对鳞翅目、鞘翅目和半翅目等多种害虫以及螨类都有一定的防治效果。关于拟除虫菊酯类杀虫剂对某种环境生物的单一安全性评价的研究颇多,但缺乏系统的评价。根据《化学农药环境安全评价试验准则》,测定了8％高效氯氟氰菊酯微乳剂对6种非靶标环境生物鹌鹑、蜜蜂、家蚕、斑马鱼、大型溞和蚯蚓的毒性,并进行了环境安全性评价。8％高效氯氟氰菊酯微乳剂对鹌鹑的经口毒性7 d LD50为54．4762 mg· kg-1,属中毒;对蜜蜂经口毒性的48 h LC50为2．7391 mg· L-1,属高毒;对家蚕和斑马鱼的96 h LC50分别为0．0067和0．0007 mg· L-1,均为剧毒;对大型溞的抑制毒性EC50（48 h）为1．2716 mg· L-1,属中毒;对蚯蚓的14 d LC50为32．3313 mg· kg-1,属低毒。本文明确了高效氯氟氰菊酯微乳剂对环境生物的毒性及安全性,可为其在农业生产中的合理利用及其对环境生物危害的风险控制提供依据。     

红裸须摇蚊幼虫生物标志物系统对苯酚的响应

以红裸须摇蚊4龄幼虫为对象,测定了苯酚对摇蚊幼虫急性毒性、体质量、化蛹率及体内保护酶和解毒酶活性的影响.结果表明:苯酚对摇蚊4龄幼虫6、24、48、72和96 h半致死浓度LC50分别为222.52、134.86、67.74、47.39和35.76 mg.L-1;亚致死剂量苯酚(0.4、4和40 mg.L-1)处理降低摇蚊4龄幼虫干湿质量和化蛹率;摇蚊4龄幼虫暴露于苯酚液72 h,过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、谷胱甘肽S转-移酶(GST)和羧酸酯酶(CarE)均对苯酚暴露做出响应,且随着浓度增加和暴露时间的延长呈现一定的剂量-时间效应,而摇蚊体内酸性磷酸酯酶(ACP)和碱性磷酸酯酶(ALP)对苯酚暴露响应较迟钝,仅高浓度(40 mg.L-1)长时间(48 h和72 h)的胁迫才会产生显著抑制作用.表明摇蚊体质量、化蛹率和CAT、SOD、GST、CarE可作为监测苯酚水体污染的生物标志物.     

泽蛙（蝌蚪）和蜘蛛对农药的敏感性与急性毒性分级

泽蛙和蜘蛛是稻田害虫的重要天敌。通过室内和田间毒性试验,发现它们对拟除虫菊酯、有机氯、沙蚕毒素及治螟磷等农药,特别是对拟除虫菊酯的纯活性异构体敏感．蝌蚪群体异质性比蜘蛛小,对农药更敏感．根据田间毒性试验,室内用４８小时的致死中浓度,田间用安全浓度和药量安全指数,可评价农药对它们的安全性,其急性毒性可分为剧毒、高毒、中等毒和低毒四级．     

Acute toxicity and cholinesterase inhibition of the nematicide ethoprophos in larvae of gar Atractosteus tropicus (Semionotiformes: Lepisosteidae)

Biomarkers are a widely applied approach in environmental studies. Analyses of cholinesterase (ChE), glutathione S-transferase (GST) and lipid peroxidation (LPO) are biomarkers that can provide information regarding early effects of pollutants at different biochemical levels on an organism. The aim of this study was to evaluate the biomarker approach on a Costa Rican native and relevant species. For this, larvae of gar (Atractosteus tropicus) were exposed to the organophosphorus nematicide, ethoprophos. Acute (96hr) exposure was conducted with pesticide concentrations ranging from 0.1 microg/L to 1 500 microg/L. The 96hr LC50 calculated was 859.7 microg/L. After exposure, three biomarkers (ChE, GST and LPO) were analyzed in fish that survived the acute test. The lowest observed effect concentration (LOEC) regarding ChE activity inhibition was 50 microg/L. This concentration produced a significant inhibition (p<0.05) of the enzyme by 20%. The highest concentration tested without showing any effect on ChE activity and therefore considered as no observed effect concentration (NOEC) was 10 microg/L. Ethoprophos concentration of 400 microg/L caused a ChE inhibition by 79%. In this study, no significant variations (p>0.05) in GST activity and LPO were observed in A. tropicus larvae after exposure to ethoprophos.     

Marker enzyme assessment in the liver of cyprinus carpio (L.) exposed to 2,4-D and azinphosmethyl

The potential utility of antioxidant enzymes and lipid peroxidation as indicators of exposure to 2,4-D and azinphosmethyl together with the toxic effects of these compounds in freshwater fish Cyprinus carpio were evaluated. Biochemical parameters were recorded spectrophotometrically in fish liver, which were exposed to a single dose of 2,4-D and azinphosmehtyl (1/3 LC(50)), and their mixture at 1:1 ratio for 24, 48, 72, and 96 h. The most sensitive parameter was glutathione S-transferase (GST) activity, which significantly increased with experimental exposures. Glucose 6-phosphate dehydrogenase activity did not change after 24 and 48 h while there was an elevation after 72 h in all exposure groups. The activity decreased only when these were applied in combination at 96 h. Superoxide dismutase activity increased after azinphosmethyl exposure for 48 and 96 h. 2,4-D decreased the activity after 24 h while the activity remained at the same level with control after 48 h. An elevation was found between 72 and 96 h. Mixture treatment did not changed the activity. Glutathione reductase and catalase enzyme activities, and malondialdehyde levels remained constant in all the treatment groups compared with controls. These results suggest that induction of GST activity may be used as biomarker for the assessment of water pollution in C. carpio.     

Susceptibility of the bedbug,Cimex lectularius,to selected insecticides and various treated surfaces

Abstract. Adult bedbugs, Cimex lectularius, were exposed for 24 h (25^oC) to filter paper treated with various dilutions of the technical grade of nine insecticides dissolved in acetone to determine the concentration-response relationships. The order of toxicity, from most to least based on the LC₅₀'s was: dichlorvos, pirimiphos methyl, lambda-cyhalothrin, bendiocarb, permethrin, malathion, carbaryl, tetrachlorvinphos, and fenvalerate. The residual toxicities of commercial formulations of six of the chemicals diluted with water and applied to wood, cardboard, cloth and galvanized metal, were determined by exposing adult bedbugs at 3,7 and 12 weeks after treatment. The formulation of bendiocarb (FICAM® 76% W) had little residual activity on all surfaces at 12 weeks after treatment. The formulation of carbaryl (SEVIN® 21.5% L) was toxic to bedbugs on all surfaces at 12 weeks after treatment, but required high concentrations on wood, cardboard, and cloth. The formulation of pirimiphos methyl (ACTELLIC® 57% EC) had no residual activity on any of the surfaces at 12 weeks after treatment. The formulation of tetrachlorovinphos (RABON® 50% W) had residual activity for 12 weeks on all surfaces except metal. The formulation of permethrin (ATROBAN® 11% EC) had residual activity on only metal and wood while the formulation of lambda-cyhalothrin (KARATE® 13.1% EC) had residual activity 12 weeks on all surfaces.     

Horn fly (Diptera: Muscidae) insecticide resistance in Kentucky and Arkansas

The effect of previous insecticide use patterns for horn fly control on the susceptibility spectrum of horn fly (Haematobia irritans [L.]) populations from Kentucky and Arkansas is described. Populations of horn flies from both states were tested with three pyrethroids (cyhalothrin, cypermethrin, and permethrin), three organophosphates (diazinon, pirimiphos methyl, and tetrachlorvinphos), and a chlorinated hydrocarbon (methoxychlor). Dose-mortality data indicated insecticide resistance in Arkansas and Kentucky. Two permethrin-resistant horn fly populations in Kentucky that did not have a history of exposure to methoxychlor were cross-resistant to this chlorinated hydrocarbon. Horn fly populations from both states with a history of at least three consecutive years of exposure to various pyrethroid ear tags were subsequently exposed to cattle tagged with cyhalothrin-impregnated ear tags for 15-16 wk. Such exposure resulted in a decrease in susceptibility to this pyrethroid (ranging from approximately 30 to greater than 100-fold) when compared with levels before treatment. Horn fly populations from Arkansas resistant to cyhalothrin (as a result of exposure to cyhalothrin ear tags) were cross-resistant to pirimiphos methyl. Seasonal exposure of an Arkansas and Kentucky horn fly population to cattle with ear tags impregnated with pirimiphos methyl resulted in a significant decrease in susceptibility to this organophosphate.     

Effect of microcystin on ion regulation and antioxidant system in gills of the estuarine crab Chasmagnathus granulatus (Decapoda,Grapsidae)

The objective of this work was to evaluate mechanisms of microcystin toxicity on crustacean species. Adult male crabs of Chasmagnathus granulatus (13.97+/-0.35 g) acclimated to low salinity (2 per thousand ) were injected with saline (control) or Microcystis aeruginosa aqueous extract (39.2 microg/l) at 24 h intervals for 48 h. After the exposure period, the anterior and posterior gills were dissected, measuring Na(+),K(+)-ATPase and glutathione-S-transferase (GST) activity. Total oxyradical scavenging capacity (TOSC) and lipid peroxides (LPO) content were also determined. Na(+),K(+)-ATPase activity in anterior gills was significantly lower in crabs injected with toxin than in control crabs, while no significant difference in the enzyme activity was detected in posterior gills. Both sodium and chloride concentration in the hemolymph were not affected by toxin exposure. Significant changes in GST activity were detected in posterior gills, with higher values being observed in the toxin-injected crabs. Crabs exposed to microcystin also showed a significant increase in the TOSC value against peroxyl radicals, for both anterior and posterior gills. Lipid peroxides level did not change in both gill types after exposure to the toxin. The increased levels of TOSC suggest the occurrence of a crab response against oxidative stress induced by toxin injection, which prevents lipid peroxidation.     

Susceptibilities of northern fowl mite,Ornithonyssus sylviarum (Acarina: Macronyssidae), and chicken mite,Dermanyssus gallinae (Acarina: Dermanyssidae), to selected acaricides

The relative toxicities of ten acaricides to northern fowl mite,Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken mite,Dermanyssus gallinae (De Geer), were determined simultaneously by holding the mites inside disposable glass Pasteur pipettes previously immersed in acetone solutions of various concentrations (w/v) of technical grade acaricides. The LC₉₀s (parts per million) of the acaricides after 24 h exposure for the northern fowl mite and the chicken mite, respectively, were: bendiocarb (13.1, 0.18), tetrachlorvinphos (14.5, 4.07), carbaryl (15.0, 0.83), pirimiphos methyl (18.3, 2.03), permethrin (23.1, 8.46), lambda cyhalothrin (80.7, 11.4), dichlorvos (252.8, 3.75), malathion (238.4, 6.59), amitraz (6741, 9430) and fenvalerate (>10000, 60.2). After 48 h exposure there were only slight increases in mortalities of both species except for increased mortalities for the northern fowl mite with lambda cyhalothrin, amitraz and fenvalerate, and for the chicken mite with amitraz.     

Biochemical indicators of hepatotoxic effects of pesticides

Pesticides can cause damage to man and beneficial organisms. Some sub-lethal effects of pesticides were studied in birds with a view to identifying characteristic biochemical responses that may be useful for the monitoring of exposure to sub-lethal levels in the field. Pesticides were used: demeton-S-methyl, (DSM), chlorpyriphos, chlorfenviphos, triazophos, pirimicarb, methiocarb and permethrin. Blood was collected before dosing, and 2, 6, 24, 48 and 72 hours after the treatment from the brachial vein of birds. Enzyme activities were assayed in the plasma or serum samples obtained. The assays used were GOT, MDH, GDH, SDH, GAMMA GT and ChE. The results showed an increase in plasma and serum GOT and gamma-GT levels were found in all animals treated with the previous pesticides. The level of ChE increased in birds after treatment with permethrin. It was concluded that the pesticides cause structural and functional changes in the liver and also, the measurement of the previous parameter activities may be useful for assessing exposure and sub-lethal effects of pesticides on the wildlife.     

Muscular and brain cholinesterase sensitivities to azinphos methyl and carbaryl in the juvenile rainbow trout Oncorhynchus mykiss

The organophosphate azinphos methyl (AzMe) and the carbamate carbaryl are the insecticides mostly used in the irrigated valley of Río Negro and Neuquén, Patagonia, Argentina. Juvenile rainbow trout were exposed to AzMe and carbaryl and the sensitivity of skeletal muscular cholinesterase (ChE) and the time course of inhibition and recovery were evaluated. EC50 values demonstrated that AzMe was a stronger in vivo inhibitor of muscular ChE (1.05+/-0.23 microg/L) than carbaryl (270+/-62.23 microg/L). Muscular ChE was significantly less sensitive to both insecticides than brain ChE. EC50 values obtained for muscular ChE were closer than those for brain ChE to the respective pesticide lethal concentrations, pointing out the relevance of the muscular enzyme in determining acute toxicity. The recovery process of ChE activity after carbaryl exposure (500 microg/L) was fast, whereas no significant recovery was observed with AzMe (1 microg/L) after 21 days in uncontaminated media. Brain and muscular ChE were inhibited and showed a significant but not complete recovery after three consecutive 48-h exposures to AzMe (1 microg/L) followed by a recovery period of 7 days. This scheme mimics the periodical application of the insecticides in the region and suggests a certain probability of a sustained ChE inhibition under field conditions, affecting fish development and survival.     

Hepatic accumulation and effects of microcystin-LR on juvenile goldfish Carassius auratus L

After intraperitoneal injection of microcystin-LR (MC-LR) (125 microg kg(-1) body wt.), the concentration of MC-LR in the liver of juvenile goldfish Carassius auratus (30 g body wt.) was assayed by a modified protein phosphatase inhibition method. A temporary accumulation occurred from 3 to 48 h post-injection, followed by a significant decrease between 48 and 96 h. Under our experimental conditions, contamination by MC-LR did not change ionic homeostasis, as attested by blood osmolality values and gill Na(+)/K(+) ATPase activity. Light microscopy observations revealed lesions and cellular necrosis progression, which was concomitant with an increase in enzyme activity of plasma aspartate aminotransferase (AspAT), alanine aminotransferase (AlaAT) and L-lactate dehydrogenase (LDH) and with a decrease of hepatic glutathione-S-transferase (GST) activity. Structural alterations and enzymatic activity modifications became significant within 24 h post-injection. Recovery of hepatocytes on day 21 after MC-LR injection was evident, together with a decrease in the MC-LR equivalent content of the liver.