中药材中氨基甲酸酯类农药残留量的反相高效液相色谱法

目的:测定三七、西洋参、白芍和当归中涕灭威、呋哺丹、西维因3种氨基甲酸酯农药残留量。方法:用丙酮超声波提取,二氯甲烷液液分配萃取,中性氧化铝层析柱(25cm×1.5 cm)净化,采用YWG-C_(18)色谱柱(250mm×4.6 mm,5μm),以乙腈-水(38:62)为流动相,流速为1.0 mL·min~(-1),检测波长分别为200nm(检测涕灭威、 呋喃丹)和220nm(检测西维因);检测浓度分别为:涕灭威0.52μg·mL~(-1) ,呋喃丹0.40μg·mL~(-1) ,西维因0.11μg·mL~(-1);进样量为20μL。结果:涕灭威、呋喃丹、西维因添加回收率分别为83.1％～91.5％,90.1％～110.6％,94.0％～96.9％;RSD分别为3.5％～8.0％,1.9％～7.6％,2.9％～6.3％;检测限(S/N=3)分别为:涕灭威2.4×10~(10)g,呋喃丹8.4×10~(-11)g,西维因4.4×10~(11)g。结论:本方法分离净化效果好,选择性强,灵敏度高,操作简便等。     

Effects of salinity on aldicarb toxicity in juvenile rainbow trout (Oncorhynchus mykiss) and striped bass (Morone saxatilis x chrysops).

Fluctuations in several environmental variables, such as salinity, can influence the interactions between organisms and pollutants in aquatic organisms, and, therefore, affect the toxicity of xenobiotics. In this study, after 2 species of fish, rainbow trout (Oncorhynchus mykiss) and hybrid striped bass (Morone saxatilis x chrysops) were acclimated to 4 salinity regimens of 1.5, 7, 14, and 21 ppt for 1 week and then exposed to 0.5 mg/l aldicarb. Mortality, brain, and muscle cholinesterase levels were measured after 96 h. Rates of (14)C-aldicarb sulfoxide formation were determined in kidney (trout only), liver, and gill microsomes from each species acclimated to the 4 salinity regimens. Salinity significantly enhanced aldicarb toxicity, cholinesterase inhibition, and (14)C-aldicarb sulfoxide formation in rainbow trout but not in striped bass. In vitro incubations with (14)C-aldicarb and the cytochrome P450 (CYP) inhibitor, N-benzylimidazole, did not significantly alter aldicarb sulfoxide formation in tissue microsomes from either species of fish, indicating CYP did not contribute to aldicarb sulfoxidation. Salinity increased flavin-containing monooxygenase (FMO) mRNA expression and catalytic activities in microsomes of liver, gill, and kidney of rainbow trout, which was consistent with the salinity-induced enhancement of aldicarb toxicity. Salinity did not alter FMO mRNA expression and catalytic activities in striped bass, which was also consistent with the lack of an effect of salinity on aldicarb toxicity in this species. These results suggest that salinity-mediated enhancement of aldicarb toxicity is species-dependent, and at least partially due to the salinity-related upregulation of FMOs, which, in turn, increases the bioactivation of aldicarb to aldicarb sulfoxide, which is a more potent inhibitor of cholinesterase than aldicarb.     

In vivo acetylcholinesterase inhibition, metabolism, and toxicokinetics of aldicarb in channel catfish: role of biotransformation in acute toxicity.

The carbamate pesticide, aldicarb, demonstrates significant acute toxicity in mammals, birds, and fish through the inhibition of acetylcholinesterase (AChE), and may present high potential for exposure of aquatic organisms during periods of runoff. Toxicity studies have shown that channel catfish are less sensitive to the acute toxic effects of aldicarb than are rainbow trout or bluegill. An earlier in vitro study suggests that the aldicarb resistance in catfish may be related to a low level of bioactivation to the potent aldicarb sulfoxide. The current study examines the toxicity, AChE inhibition, plasma kinetics, and in vivo metabolism of aldicarb in channel catfish. A 48-h LC50 of 9.7 mg/l was determined for juvenile channel catfish. Mortality was accompanied by dramatic loss of brain AChE. Further characterization of tissue-level effects suggests that muscle AChE plays a causal role in mortality. Aldicarb was metabolized in channel catfish to aldicarb sulfoxide, along with the formation of minor hydrolytic products. The toxicokinetics of aldicarb in catfish are bi-compartmental with rapid elimination (t1/2 = 1.9 h). Plasma AChE was inhibited in a pattern similar to that of the elimination of total aldicarb-derived compounds. A comparison of aldicarb uptake between catfish and rainbow trout showed no difference in compound absorbed in 24 h. The pattern of in vivo metabolism, however, was quite different between these species. Rainbow trout produce significantly more hydrolytic derivatives and have a 3-fold higher aldicarb sulfoxide to aldicarb ratio at 3 h. These data give strength to the hypothesis that a slower rate of bioactivation in the catfish (vs. rainbow trout) is acting as a protective mechanism against the acute toxicity of aldicarb.     

Acute and sublethal effects of two insecticides on earthworms (Lumbricus terrestris L.) under laboratory conditions

Earthworms (Lumbricus terrestris L.) were exposed to commercial formulations of endosulfan and aldicarb for 2, 7, and 15 days, and the LC(10), LC(25), and LC(50) were determined. Worms were then exposed to LC(10), LC(25), and LC(50) concentrations of endosulfan and LC(10) and LC(25) concentrations of aldicarb. The growth rate and total protein content were determined and related to endosulfan and aldicarb residues in soil and earthworms. Aldicarb was more toxic than endosulfan under the experimental conditions. The residues of endosulfan and aldicarb caused a significant reduction in the growth rate and total protein content of earthworms. The residues of endosulfan and aldicarb were monitored in soil and earthworms after 2, 7, and 15 days of exposure. The residues remaining in the soil after the experiments ranged between 37.75% and 68.54% of the applied concentration for endosulfan and between 10.13% and 67.71% of the applied concentration for aldicarb. Small amounts of both insecticides were detected in worms, and accumulation was more important for endosulfan. This study proposes the use of growth rate and total protein content as biomarkers for contamination by endosulfan and aldicarb.     

Nutrient effects on microbial transformation of pesticides in nitrifying surface waters

Multivariate analyses of a large set of physical, chemical, and biological measurements indicated possible effects that specific surface water properties have on biotransformation rates of pesticides. In this study, we investigated the roles of Mg, Mn, and P, which were identified as relevant, discriminating environmental variables in the overall biotransformation process as it occurred under nitrifying conditions. Nematicide aldicarb, herbicides simazine and MCPA were selected as their chemical group representatives. Series of mechanically aerated incubation vessels were set up to test nutrient enrichment effects on microbial development and subsequent pesticide transformation. Accounting for alterations in system conditions, relevant (physico)chemical characteristics were monitored. An increase in total microbial population was observed in surface water samples in the presence of both aldicarb and simazine. No increase was observed when MCPA was added, which was probably cometabolized. Large phosphorus concentrations not only favored bacterial growth, but also increased the residence time of dissolved Mn which under certain conditions promoted biotransformation. Furthermore, PO₄ enrichment decreases aldicarb's aerobic metabolites' concentrations. Simazine was persistent over a period of at least 80 days, except for a short period coinciding with the nitrification period in which NH dissipates and NO₂ and NO are formed. Selective bacterial growth was observed on simazine's transformation product DES. Relationships of Mg/Mn concentrations to MCPA transformation rates, and of PO₄/P_T concentrations to aldicarb transformation rates, are presented. These relationships are assessed as environmental indicators for potential biotransformation, but only under conditions warranting development and growth of a degrading population over a prolonged period. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 329–338, 1999     

Assessment of the ability of propoxur,methomyl, and aldicarb,three carbamate insecticides,to induce micronuclei in vitro in cultured Chinese hamster ovary cells and in vivo in BALB/c mice

Three carbamate insecticides (propoxur, methomyl, and aldicarb) were evaluated for their ability to induce micronuclei (MN) in vitro using cultured Chinese hamster ovary (CHO) cells, and in vivo in mouse bone marrow erythrocytes. In vitro, all three insecticides induced a significant increase in micronucleated binucleate cells, which was generally both dose and sample time dependent. The in vivo studies involved treating male BALB/c mice by different routes, either once or on 3 consecutive days, followed by multiple or single sampling. Treatment by intraperitoneal injection or oral gavage induced a significant increase in micronucleated reticulocytes (MNRETs) in peripheral blood. For all three chemicals, the MN response depended on sample time and the number of treatments, while for aldicarb, the response depended also on the route of exposure. These positive results demonstrate that propoxur, methomyl, and aldicarb are capable of inducing structural and/or numerical chromosomal aberrations in mammalian cells either in vitro or in vivo. Furthermore, based on the results obtained, an optimal in vivo MN protocol for carbamate insecticides is a single treatment followed by blood sampling at 24 and 48 hr after treatment. Environ. Mol. Mutagen. 29:386–393, 1997 © 1997 Wiley-Liss, Inc.     

Effect of 17beta-estradiol and testosterone on the expression of flavin-containing monooxygenase and the toxicity of aldicarb to Japanese medaka, Oryzias latipes.

Previous studies in our laboratory indicated gender differences in salinity-enhanced acute toxicity of aldicarb in Japanese medaka with females being more susceptible. In the current study, the effects of the sex steroids, 17beta estradiol (E2) and testosterone (T) on aldicarb toxicity was examined. Adult Japanese medaka were separated by sex and exposed to 100 microg/l E2 or T for 6 days followed by exposure to the 96-h LC50 (0.5 mg/l) of aldicarb. The toxicity of aldicarb to adult males was significantly lowered by E2 and T whereby the mortality percentage was reduced to 23.3 +/- 5.8% and 3.3 +/- 5.8%, respectively, compared to the fish not receiving steroids (46.7 +/- 5.8% mortality). In females, T caused significant reduction in aldicarb toxicity to 16.7 +/- 5.8%, while E2 significantly enhanced the toxicity to 96.7 +/- 5.8% mortality. Since the flavin-containing monooxygenase (FMO) enzyme system had been shown to play a critical role in aldicarb toxicity, the effect of E2 and T on FMO expression was examined. Gill FMO activity showed a direct correlation with the overall toxicity of aldicarb in both male and female medaka. Expression of FMO1-like protein was significantly reduced by T in male livers and gills, and T did not affect the expression of FMOs in female tissues. In contrast, E2 significantly reduced FMO1-like protein expression in male gills and female livers, as well as FMO3 expression in both male and female livers, but significantly increased gill FMO1 expression in females. Since aldicarb acts by inhibiting the enzyme cholinesterase (ChE), the effect of sex hormones on the activity of this enzyme was also examined. In both male and female medaka, T counteracted the inhibitory effect of aldicarb on muscle ChE. In male fish, E2 had similar effects but did not seem to counteract the ChE inhibition in females. In conclusion, E2 and T modulation of aldicarb toxicity in Japanese medaka seems to be mediated via alteration of gill FMO and ChE actitivies.