恩诺沙星在鲫鱼肝微粒体中的代谢及代谢关键酶

抗生素因具有抗菌谱广、杀菌性强等特点而被广泛应用于人类医药、畜牧业、农业和水产养殖业。其进入水生生物体内后,会在药物代谢酶的作用下发生代谢转化,产生生态毒性。采用鲫鱼肝微粒体体外孵育法,探究恩诺沙星细胞色素P450酶作用下的代谢转化过程,并通过代谢抑制实验确定关键的代谢酶。结果表明,恩诺沙星体外代谢过程符合一级动力学方程,当恩诺沙星暴露浓度为1 mg·L-1时,其在肝微粒体中的消除速率常数(k)最大为0.00303 min-1,半衰期(t1/2)最短为228.8min,应用高效液相色谱串联质谱(HPLC-MS/MS)技术,检测到了恩诺沙星脱乙基产物和羟基化产物;代谢抑制实验结果表明,CYP3A4在恩诺沙星代谢过程中起主要作用,是恩诺沙星代谢的关键酶。本研究结果为深入了解恩诺沙星在水生生物体内的代谢转化及其生态风险提供了基础数据。     

2,3,7,8-TCDD代谢产物的液-质联用分析

采用肝微粒体体外温孵法,对2,3,7,8-TCDD在大鼠肝微粒体中进行体外代谢研究.利用实验中所建立的液相色谱串联质谱方法对其代谢产物进行直接分析,共鉴别出两类代谢产物,分别为2个单羟基化代谢产物(2-OH-1,3,7,8-TCDD和1-OH-2,3,7,8-TCDD)和双羟基化脱氯的代谢产物.     

羟基化多溴联苯醚(OH-PBDEs)在小鼠肝脏微粒体的体外代谢及对CYP450酶活性的影响

羟基化多溴联苯醚(OH-PBDEs)是一类具有内分泌干扰效应的酚类化合物,生物毒性要高于母体多溴联苯醚(PBDEs),研究OH-PBDEs的体外代谢行为对于理解其在生物体内的富集转化具有重要意义。以小鼠肝脏微粒体作为研究对象,考察了3-OH-BDE-47、5-OH-BDE-47、6-OH-BDE-47和2’-OH-BDE-68在小鼠肝脏中的体外代谢,并分别研究了浓度为0.1、0.2、0.4、0.6、1.0μmol·L-1条件下4种OH-PBDEs对细胞色素P450酶系中7-乙氧基香豆素-O-脱乙基酶(ECOD)、7-乙氧基异吩唑酮-O-脱乙基酶(EROD)和苯胺4-羟基化酶(ANH)活性的影响。结果表明,4种OH-PBDEs在小鼠肝脏微粒体中均能够快速代谢,代谢率分别为80%(3-OH-BDE-47)、42%(5-OH-BDE-47)、86%(6-OH-BDE-47)和63%(2’-OH-BDE-68)。实验所设OH-PBDEs各浓度对微粒体的ECOD活性无显著性抑制作用,但对EROD的活性均表现出相同的显著抑制作用;4种OH-PBDEs表现出不同的ANH活性影响,即3-OH-BDE-47对ANH活性具有抑制作用,5-OH-BDE-47具有诱导作用,而6-OH-BDE-47和2’-OH-BDE-68对ANH活性无显著性影响。     

过氧化氢酶活性及活性抑制的测定

广泛存在微生物及动植物体内的过氧化氢酶已应用于生态毒理及生态化学的研究领域，本文主要介绍了通过肝过氧化氢酶活性抑制的测定，来估价受试化学品对水生生物急性及亚急性效应的方法。     

水产品中多氯联苯代谢产物的研究进展

多氯联苯是斯德哥尔摩公约首批禁止的持久性有机污染物之一.残留在环境中的多氯联苯,由于其亲脂特性可在生物体内进行生物积累以及在食物链中产生生物放大效应,并在肝脏中代谢产生羟基多氯联苯、甲磺基多氯联苯、多氯联苯硫酸盐等.代谢产物在水生生物体内会产生与内分泌相关的毒性作用,继而导致的水产品质量安全问题,引起了国际范围的持续关注.本文从多氯联苯代谢产物的定性定量分析方法、毒性效应及机理、多氯联苯生物转化机制等方面展开综述,并对目前全球范围内关于水产品中多氯联苯代谢产物同系物类型、残留水平以及对其影响水产品质量安全的研究进展进行了全面的总结概述.     

手性药物的水环境行为、毒性效应及生态风险

药物污染已经成为一个重要的环境问题,目前生产和使用的药物中大部分为手性药物,进入地表水环境后,2个对映异构体在生物降解和生态毒性等方面可能存在显著的差异。本文以8种手性药物为研究对象,系统综述了手性药物在水环境中的暴露特征和降解转化规律,分析其对不同生物靶点的毒性效应和机理,探讨了其对水生态系统的潜在风险。结果表明,8种手性药物在国内外地表水中的检出浓度达到μg·L^-1水平。手性药物在地表水环境中的对映体构成受药物种类、环境条件和时间的影响;布洛芬、普萘洛尔等差异显著的手性药物可以作为污染源示踪的特征污染物;不同污水处理工艺的对映体选择性也有较大差异,导致污水处理厂出水中手性药物对映体分数(enantiomer fraction, EF)值不同。由于手性药物在生物体内发生手性代谢和手性转化,导致体外毒性实验与体内毒性效果差异很大,手性药物在不同水生生物类群体内的受体或生物利用率有所差异,从而表现出不同的立体选择性。基于外消旋体的生态风险评估研究表明,目前布洛芬、卡马西平和萘普生等手性药物对水生生物具有潜在的风险,而不同对映体对水生生物的毒性存在一定差异。因此,有必...     

三氯生对水生生物的毒性效应研究进展

三氯生(TCS)作为一种广谱抗菌剂,在个人护理品中的广泛应用,将使其不可避免地释放到水环境中.随着在河流、湖泊、河口系统等水环境以及水生生物体内检测到TCS,TCS对于水生生物的生态毒理效应引起了学者们的广泛关注.本文概述了TCS在水环境及水生生物体内的赋存状况,归纳总结了TCS对水生生物的急性毒性、亚急性毒性、酶及基因毒性、内分泌干扰性及其降解产物毒性,最后展望了TCS对水生生物的生态毒理效应这一研究领域的发展方向.     

3种有机磷农药对水生生物的乙酰胆碱酯酶抑制效应的物种敏感度分析初探

通过筛选敌敌畏、马拉硫磷和对硫磷3种有机磷农药对水生生物的急性毒性数据和乙酰胆碱酯酶抑制效应数据,构建物种敏感度分布曲线进行了比较分析。结果表明,敌敌畏对水生生物的急性毒性和乙酰胆碱酯酶抑制效应的大小顺序为:酶体内抑制效应酶体外抑制效应急性毒性;马拉硫磷和对硫磷的乙酰胆碱酯酶抑制效应数据不足但趋势相似,顺序为:酶体内抑制效应急性毒性酶体外抑制效应。敌敌畏的急性毒性和酶体外抑制效应的5%危害浓度(HC5)分别为2.07μg·L~(-1)和1.53μg·L~(-1),两者相差1.4倍。在水质基准推导中,乙酰胆碱酯酶抑制效应数据对有机磷农药的水生生物基准具有重要的参考价值。     

羟基多溴联苯醚(3'-OH-BDE-7)的大鼠体外肝代谢研究

本文利用液相色谱-质谱联用技术,建立了羟基多溴联苯醚3'-OH-BDE-7在S.D.大鼠肝匀浆中的体外代谢研究方法.实验结果表明,3'-OH-BDE-7的主要代谢产物为2,4-二溴苯酚和二羟基多溴联苯醚(diOHPBDEs),并且其在温孵30min,时代谢转化率为90%.3'-OH-BDE-7的代谢研究为其它羟基多溴联...     

单甲脒在大鼠体内的吸收,代谢和排出的研究

大鼠经口灌喂单甲脒后，通过测定实验动物不同时间的血、尿及内脏中单甲脒和代谢产物２，４－二甲基苯胺的含量，研究了单甲脒在大鼠体内的呼收、代谢和排出的变化规律。单甲脒经消化道被迅速吸收，４８ｈ内９０％在肝脏代谢转化。７２ｈ内９０％以代谢产物的形式随尿液排出体外。     

The effect of lead bioaccumulation on haem biosynthetic enzymes in fish

The bioaccumulations of lead in the liver and hepatic microsomes of fish after 1, 3, 7, 14, 28, and 45 days exposure were studied. In addition, the relationship between the bioaccumulated lead in both hepatic microsomes and the liver and their haem biosynthetic enzymes were studied. Lead toxicity was shown to result in a depression of the microsomal mixed function oxidase system, as assessed by a decrease in hepatic microsomal cytochrome P-450 and b5 content and by a decrease in the activity of the enzymes aniline hydroxylase and aminopyrine demethylase. Lead had a more marked effect on cytochrome P-450 than b5. The activity of the rate-limiting enzyme of haem biosynthesis, delta-aminolevulinic acid synthase, was inversely correlated with the microsomal cytochrome P-450 content. The activity of the heam biosynthetic enzymes delta-aminolevulinic acid dehydratase, coproporphyrinogen oxidase and ferrochelatase were decreased by increasing lead pretreatment. The activity of the haem catabolic enzyme, haem oxygenase, was increased by concentration and length of time to lead exposure.     

Effects of Cd2+ exposure on key life history traits and activities of four metabolic enzymes in Helicoverpa armigera (Lepidopteran: Noctuidae)

Cadmium (Cd) is a toxic non-essential element accumulated easily in living organisms due to its non-biodegradable nature. A slight increase in Cd levels will threaten the health of terrestrial and aquatic organisms. Therefore, Cd contamination and its effects on the ecosystems and organisms have become a major topic of eco-toxicological research. The present study investigated the eco-toxicological effects of Cd-supplemented diet on some life history traits and specific enzyme activities of carboxylesterase (CarE), glutathione S-transferase (GST), acetylcholinesterase (AChE) and cytochrome P450 monooxygenases (P450s) in the cotton bollworm, Helicoverpa armigera. The results showed that Cd significantly decreased larval survival, pupation and emergence, and reduced body mass of the sixth instar larvae, pupae, adult moths and female fecundity. Cd-supplemented diet also delayed the development of larvae and pupae and shortened the life span of the cotton bollworm moth. In addition, dietary Cd inhibited the activities of GST, CarE and P450, but increased AChE activity of the sixth instar larvae. We concluded that life history traits and metabolic enzymes are sensitive to Cd stress in the cotton bollworm. These parameters are potential biomarkers for monitoring environmental stress in Lepidopteran insect pests.     

氯吡嘧磺隆和镉复合对斑马鱼肝脏的影响

为了探究污染物镉和氯吡嘧磺隆复合污染对非靶标生物斑马鱼的毒性作用,通过急性毒性试验,获得镉和氯吡嘧磺隆对斑马鱼的LC50.以LC25作为0水平,设置9个处理组进行试验,检测不同处理组斑马鱼96 h死亡率、斑马鱼肝脏中CAT、MDA和羧酸酯酶CarE.检测结果表明,镉和氯吡嘧磺隆对斑马鱼存在交互作用,当水体中镉浓度为3....     

Adverse effects of chromium on amino acid levels in freshwater fish Clarias batrachus (Linn.)

Various heavy metals released into the rivers and lakes affect aquatic fauna including Clarias batrachus. Elevated levels of chromium (Cr) in aquatic organisms, especially fish, represent an ecological and human concern. Amino acid levels were estimated in five tissues (gills, liver, kidneys, muscle, and brain) of C. batrachus after 28 days of exposure to Cr. This study showed that Cr elevated levels of free amino acids in organs of fish C. batrachus, indicating a compensatory mechanism to counter sublethal metallic stress. Data suggest that the measurement of amino acids may serve as a biomarker for Cr toxicity in fish.     

Cytochrome P450 1A activity in liver and fixed wavelength fluorescence detection of polycyclic aromatic hydrocarbons in the bile of tongue-fish (Cynoglossus acrolepidotus, Bleeker) in relation to petroleum hydrocarbons in the eastern Gulf of Thailand.

This investigation was conducted in an area of oil spill along the east coast of Thailand to examine the relations among cytochrome P450 1A activity in liver and PAHs in the bile of the tonguefish and petroleum hydrocarbons in the sediments. PAH sediment concentrations in the reference and oil spill areas were 5.03 +/- 0.42 and 0.21 +/- 0.043 microg(-1) dry weight respectively Cytochrome activity in fish liver from oil spill area was 45.40 +/- 3.50 pmoles/ min/mg protein, almost threefold higher than that from the reference sites. Flourescense detection in bile metabolites at the oil spill area, 69.8 +/- 9.9 flourescense unit was significantly higher than that at the reference sites, 22.9 +/- 5.5 and 22.2 +/- 3.5 fluorescence unit. A strong correlation was found among cytochrome P450 1A activity in liver, PAH of bile metabolites and petroleum hydrocarbons. Both cytochrome and bile metabolites activity decreased seaward varying to the distance from the oil polluted area. We concluded that both detections in tonguefish can be regarded as a complementary biomarkers for the exposure of PAHs in tropical marine environments.     

Influence of endosulfan and monocrotophos exposure on the activity of NADPH cytochrome C reductase (NCCR) of Labeo rohita (Ham)

The response of NADPH cytochrome C reductase (NCCR) activity in liver of Labeo rohita fish exposed to the pesticides, 0.25 microgl(-1) endosulfan and 2 mg/l monocrotophos was studied. In terms of specific enzyme activity (mU/mg protein) a significant level of NCCR was observed in the liver tissues of Labeo rohita exposed to the pesticides, when compared to the control fish (2.460 mU/mg protein). Increase of NCCR activity was more in the liver of the fish exposed to monocrotophos (4.595 mU/mg protein) than those exposed to endosulfan (2.850 mU/mg protein). The results demonstrate that the pesticides, endosulfan and monocrotophos, interfere with NADPH dependent monoxygenase mechanism and are effective inducers of NADPH cytochrome C reductase. The activity of NCCR in the liver tissue of Labeo rohita may serve as a useful tool for monitoring aquatic pollution.     

三唑酮在水环境中的环境行为、毒性效应及生态风险

三唑酮是目前应用最广泛的三唑类广谱杀菌剂之一,在我国的使用量有逐年增长的趋势。本研究综述了三唑酮在水环境中的环境行为、毒性效应及其对我国部分水体的生态风险。三唑酮使用后被土壤吸附和解吸,经雨水淋溶作用进入地表或地下水环境,在丰水期检出率与检出浓度较高,目前我国地表水中三唑酮最高检出浓度为12μg·L-1。三唑酮在环境中的半衰期为15~43.3 d,能够在水生生物体内累积代谢,在不同浓度下对不同类群、不同生命阶段的水生生物表现出不同的毒性效应,对应着多条有害结局路径,其中最重要的是通过抑制细胞色素P450酶活性干扰机体内激素水平,影响水生生物繁殖和生长发育,导致种群密度降低。在目前已知的暴露水平下,三唑酮对我国地表水具有潜在的生态风险,特别是丰水期稻田附近的地表水风险尤其需要关注。     

基于物种敏感性分布法的毒死蜱对稻田生态系统生态风险评价

生物敏感性分布法(Species Sensitivity Distributions,SSD)是一种基于单物种测试和概率统计学的、较高级的外推风险评估方法。该方法在国内外均被广泛应用于各种污染物风险评价中。本文选取了采用logistic和normal这2种SSD分布模型,分析了国内外毒死蜱对3组水生生物组合的毒性数据;并且获得各自SSD的HCx值。3组毒性数据分别为:浙江稻田水生生物组,长三角地区水生生物组和美国水生生物组。浙江稻田水生物SSD分布的HC5为:0.32μg·L~(-1)(logistic模型)和0.35μg·L~(-1)(normal模型);HC10为1.50μg·L~(-1)(logistic模型)和1.26μg·L~(-1)(normal模型);HC20为8.13μg·L~(-1)(logistic模型)和5.96μg·L~(-1)(normal模型);HC50为145.44μg·L~(-1)(logistic模型)和115.74μg·L~(-1)(normal模型)。据此判断水稻种植季节,稻田水域毒死蜱对食蚊鱼、鳑鲏、泽蛙蝌蚪、轮虫、常见腹足类和双壳类软体动物以及绝大多数藻类等的风险较小。利用冗余分析研究了生物物种数量、物种组成结构和拟合模型对HCx影响。结果表明:物种组成结构对HCx有较为明显的影响。具体表现为对毒死蜱较为敏感物种数量与HCx存在明显的负相关性;对毒死蜱不敏感的物种则与HCx呈现正相关性。     

Biochemical toxicity of benzene

Human exposure to benzene in work environment is a global occupational health problem. After inhalation or absorption, benzene targets organs viz. liver, kidney, lung, heart and brain etc. It is metabolized mainly in the liver by cytochrome P450 multifunctional oxygenase system. Benzene causes haematotoxicity through its phenolic metabolites that act in concert to produce DNA strand breaks, chromosomal damage, sister chromatid exchange, inhibition of topoisomerase II and damage to mitotic spindle. The carcinogenic and myelotoxic effects of benzene are associated with free radical formation either as benzene metabolites or lipid peroxidation products. Benzene oxide and phenol have been considered as proheptons. Liver microsomes play an important role in biotransformation of benzene whereas in kidney, it produces degenerative intracellular changes. Cohort studies made in different countries suggest that benzene induces multiple myeloma in petrochemical workers. Though extensive studies have been performed on its toxicity, endocrinal disruption caused by benzene remains poorly known. Transgenic cytochrome P450 IIE1 mice may help in understanding further toxic manifestations of benzene.     

鱼体中有机微污染物的定量及筛查研究进展

化学品通过多种途径进入环境水体,可对水生生物及人体健康造成潜在风险.鱼类作为水环境污染物监测的指示生物,分析鱼体内有机微污染物的分布特征是评估水环境安全的重要方法.现有污染物种类繁多,且在生物体内存在降解转化的过程,基于靶向定量分析的监测方法难以系统、准确地评估鱼体中有机污染物的暴露特征.由于具有高分辨率、高质量精度、...