两种金属和两种农药对草鱼不同发育阶段的毒性效应

进行了金属和农药对草鱼不同发育阶段影响的试验。结果表明,对草鱼胚胎孵化率的影响,96h的EC_(50)值分别为:Cd~(2+)0.078mg/L;Cu~(2+)0.17mg/L;丙体六六六1.0mg/L;对硫磷1.0mg/L。畸形症状呈现出草鱼胚胎卵黄囊水肿,心脏发育受阻而形成管状心脏、胚体弯曲(弯体)等。草鱼的不同发育阶段对金属的敏感性存在着差异:Cd~(2+)96h的LC_(50)值,胚胎为0.1—0.5mg/L;10日龄草鱼苗为0.34mg/L;120日龄草鱼种为8mg/L.Cu~(2+)96h的LC_(50)值,胚胎为0.3—0.5mg/L;10日龄草鱼苗为0.11mg/L;120日龄草鱼种为0.59mg/L.     

Specific antibody for pesticide residue determination produced by antibody-pesticide complex

A new method for specific antibody production was developed using antibody (Ab)-pesticide complex as a unique immunogen. Parathion (PA) was the targeted pesticide, and rabbit polyclonal antibody (Pab) and mouse monoclonal antibody (Mab) were used as carrier proteins. The Ab-PA complexes were generated by conjugating the two antibodies with an excessive dosage of PA. It was shown that the sensitivity of homologous enzyme-linked immunosorbent assay (ELISA) using the new antibodies was similar to that using original antibodies. However, the new mouse Pab had not only similar positive recognizing spectrum as the original Mab, but also a significantly improved sensitivity in heterologous ELISA when some recognizable competitors were applied. IC₅₀ value of ELISA based on a combination of the new mouse Pab and hapten 9 was 0.24 ng/mL, which was 445.54 times as that of the homologous ELISA. An Ab-pesticide complex may be a suitable alternative immunogen for producing highly specific antibody to improve the immunoassay sensitivity.     

The metabolic fate of 14C‐parathion by some fresh water phytoplankton and its possible effects on the algal metabolism

Abstract

The growth and total carbohydrate contents of Nostoc muscorum and Tolypothrix tenuis were greatly and significantly reduced by the application of parathion. “Chlorophyll a”, carotene biosynthesis and the rate of glucose absorption were enhanced after supplementation of parathion to the culture media of both cyanobacteria. Nitrogen released to the media, total nitrogen content and total nitrogen fixed were increased in both organisms‐ Increase in protein content was accompanied by remarkable drop in amino, peptide and ammonia fractions‐ Phosphorus uptake, RNA, DNA and total phosphorus content were accelerated to reach maximum accumulation at the highest insecticide level. In metabolism study using ¹⁴C‐labelled compound, parathion was readily degraded by Nostoc and Tolypothrix. Following ten days incubation, the aqueous fractions contained 21.1% and 18.1% of the initial activity in Nostoc and Tolypothrix respectively. TLC analysis of the hydrolytic products revealed the presence of three metabolites: p‐aminophenol, p‐nitrophenol and aminoparathion.     

Photochemical Behavior of Parathion in the Presence of Humic Acids from Different Origins

This paper reports the effect of ultraviolet radiation on the degradation of pesticide ethyl parathion in the presence of humic acids. Ethyl parathion was completely degraded in 300 min using an artificial lamp of 7.41 × 10^{? 10} einstein/s. Humic acid from peat did not influence the photochemical rate (k = 8.92 × 10^?3 min). However, in the presence of aquatic humic acid, the photochemical rate was higher (11.5 × 10^?3 min). The analytical determinations show the presence of p-nitrophenol and aminophenol in the reaction medium during the photochemical experiments. The kinetic of degradation in all experiments obeyed a first-order reaction pattern.     

UV/草酸铁络合物光解对硫磷的研究

研究了紫外光（UV）/草酸铁络合物对对硫磷的光解作用,结果表明,UV/草酸铁络合物能快速有效地光解对硫磷,且较UV/TiO2的光解效果好。对硫磷光解率随着其初始浓度的增加而降低;pH为3-5时其光解速率最快;[Fe(Ⅲ）]与[OX^2-]之比（OX^2-代表草酸根）和溶液中的溶解氧对其光解有显著影响。     

Effects of atrazine on acetylcholinesterase activity in midges (Chironomus tentans) exposed to organophosphorus insecticides

Acetylcholinesterase activity was determined for midge larvae (Chironomus tentans) exposed to either organophosphorus insecticides (OPs) alone or OP insecticides in binary combination with atrazine (200 μg/l). Although atrazine by itself did not reduce the level of acetylcholinesterase activity, atrazine in combination with chlorpyrifos significantly decreased acetylcholinesterase activity as compared to chlorpyrifos only treatments. Although similar trends existed for malathion and methyl parathion, differences were not statistically significant. These results match previously published toxicity data where atrazine, although not acutely toxic even at much higher levels, decreased EC₅₀ values for chlorpyrifos by a magnitude of 4, decreased methyl parathion values by a magnitude of 2, and did not decrease values for malathion.     

对硫磷的臭氧降解动力与机制

研究了臭氧降解对硫磷的机制、降解中间产物及影响因素。结果表明,对硫磷的臭氧降解是一个臭氧直接氧化为主和羟基自由基间接氧化为辅的氧化过程,并遵循假二级动力学。50mM离子清除剂叔丁醇使对硫磷的降解速率常数从0．09372min^-1降到0．06397min^-1,但溶液pH值对降解速率常数则无明显影响。通过GC／MS分析,确定了对氧磷为对硫磷的臭氧降解中间产物。较高的对硫磷起始浓度和离子清除剂的存在不利于对氧磷进一步降解。     

The human serum paraoxonase—Polymorphism and specificity

Human serum contains EDTA‐sensitive (Ca⁺⁺‐dependent) and EDTA‐stable (albumin) paraoxonases which hydrolyse paraoxon, 0,0‐diethyl,0–4‐nitrophenyl phosphate.

In Caucasians the EDTA‐sensitive enzyme shows a genetically determined polymorphism which is governed by two alleles. In typical Mongoloid or Negro populations this polymorphism is expressed to a lesser degree, and in a few samples (e.g. Aborigines) it cannot be observed at all. The distribution of the activity of the EDTA‐stable (albumin) paraoxonase is unimodal.

Many authors supposed that paraoxonase is an arylesterase (EC 3.1.1.2) which means that it is also able to hydrolyse phenylacetate or β‐naphthylacetate. New investigations have shown that the human serum fractions splitting paraoxon can be separated from those hydrolysing phenylacetate and related substrates.

The polymorphism of the EDTA‐sensitive human serum paraoxonase can be applied to investigations concerning specificity. From this it becomes evident that this enzyme is rather specific. Already slight changes of the paraoxon molecule lead to a decrease of activity. On the other hand the enzyme seems to hydrolyse also phosphonic acid esters and 4‐nitrophenylacetate in the same way like paraoxon (polymorphism).

There is a linkage relationship of paraoxonase with cystic fibrosis and DNA markers. According to these results the (EDTA‐sensitive) paraoxonase locus is on the human chromosome 7.

A high serum paraoxonase level actually protects serum cholinesterase (EC 3.1.1.8) and has to be considered in biological monitoring of workers exposed to parathion.     

Glutathione S-transferase activity in rats exposed to methyl parathion

Methyl parathion is an organophosphate insecticide that has been used in agriculture and the domestic sector for several years. This pesticide and others, arriving through different processes, exert significant effects on water quality with serious consequences for environmental and human health. The main objective of this study was to investigate the changes of Glutathione S-transferase enzyme activity in methyl parathion exposed rat tissues. For this purpose, wistar rats (Rattus norvegicus) were injected intraperitoneally with 7 mg kg^?1 dose of methyl parathion, while corn oil was applied to control groups in the same way. The liver, kidneys, brain and small intestine were quickly removed after 0, 2, 4, 8, 16, 32, 64, and 72 hours of injection of methyl parathion and the glutathione S-transferase activity was determined in these tissues. As a result it was seen that glutathione S-transferase activity increases in all tissues in the group of male and female rats to which methyl parathion was given. The increase of glutathione S-transferase activity may be a result of methyl parathion's toxic effect because it is one of the most important enzymes of detoxification metabolism.     

鱼类肝脏微粒体对于硫代磷酸酯类杀虫剂活化代谢率的种间差异(Species-Related Difference of Liver Microsomes of Fish in Activation of Organothiophosphorus Insecticides)

为了弄清鱼类肝脏微粒体细胞色素P450s(CYPs)对于硫代磷酸酯类杀虫剂活化代谢率的种间差别,选用斑马鱼Brachydanio rerio、麦穗鱼Pseudorasbora parva、剑尾鱼Xiphophorus helleri、篮鳃太阳鱼Leponus macrohirus四种鱼作为受试生物,选用对硫磷、马拉硫磷、毒死蜱三种硫代磷酸酯类杀虫剂作为受试药剂,以外源乙酰胆碱酯酶(AchE)的抑制率为指标,在离体状态下间接测量了杀虫剂活化代谢物的相对生成量.离体试验表明,对于对硫磷,活化代谢物生成量的高低顺序为:斑马鱼、剑尾鱼、麦穗鱼>太阳鱼(p<0.05),最高的麦穗鱼和最低的太阳鱼之间相差10.0倍;对于马拉硫磷和毒死蜱,活化代谢物生成量的高低顺序均为:剑尾鱼>太阳鱼>斑马鱼、麦穗鱼(p<0.05),最高的剑尾鱼和最低的麦穗鱼之间的分别相差66.9和137倍.毒性测定表明,对于对硫磷、马拉硫磷和毒死蜱,四种鱼96hLC50之间的最大差别分别是45、18和77倍.对马拉硫磷而言,96hLC50的种间差异特征与活化代谢物生成量的种间差异特征比较吻合,而对于对硫磷和毒死蜱而言,两者之间的吻合度较低.研究证实了肝脏CYP在活化硫代磷酸酯杀虫剂方面具有明显的种间差异,同时也证实仅以活化代谢物的离体生成量这一指标来衡量鱼类对于硫代磷酸酯杀虫剂的敏感性,其结论可能会较大幅度地偏离生测结果.尽管如此,本研究证实在所测的鱼类当中,斑马鱼属于CYP活性较低的鱼种,而这一特性很可能是造成斑马鱼对于硫代磷酸酯杀虫剂的敏感性偏低的重要原因.