Effect of fenvalerate technical grade on acetyl cholinesterase activity in Indian bullfrog Haplobatrachus tigerinus (Daudin)

Indian bullfrog Haplobatrachus tigerinus (Daudin) was exposed to sublethal dose (1/3 of LC50 I.E. 1.166 mg/kg) of fenvalerate technical grade and the effect was studied on the specific activity of acetyl cholinesterase in the different tissues of frog viz., brain, muscle, liver, kidney and testis at different time periods viz., 3,6, 12, 24, 48 and 72 hours. The inhibition of specific activity of acetyl cholinesterase was in the order of kidney > brain > muscle > liver > testis. A significant inhibition was noticed in kidney at 12 hours (-64.33%) and no effect was noticed at 3 hours in testis (+0.67%). The AChE activity was inhibited in first three hours of administration of fenvalerate in all the tissue tested. The inhibition continued upto 6 hours or 2 hours in different tissue but the recovery was started by 24 hours and almost completed by 72 hours.     

Toxicity and residue studies of fenvalerate to some selected freshwater fishes

The toxicity test of fenvalerate were conducted to fresh water fishes Labeo rohita (Hamilton), Catla catla (Hamilton), Cirrhinus mrigala (Hamilton), Aplocheilus punchex (Hamilton) and Ctenopharygodon idellus (Valenciennes). The static and continuous flow through tests were employed to determine the lethal concentration (LC50) for 24h, 48h and 96h to the test fish. It was observed that Cirrhinus mrigala is more sensitive to this pesticide followed by Applochielus punchex, Lebeo rohita, Catla catla and Ctenopharyngodon idellus. The residue analysis for qualitative confirmation was done by thin layer chromatography (TLC) to assess the deposition of pesticide in different tissues of fishes. The quantitative study of accumulation in the whole body tissue was done by Gas liquid chromatography (GLC). The quantitative residues confirm the toxic action.     

Uptake and accumulation of naphthalene by the oyster Ostrea edulis,in a flow-through system

A flow-through system was used to follow naphthalene and naphthalene metabolite accumulation in the seawater and in the tissue of the oyster Ostrea edulis. After 72 h, 82.5% of the naphthalene carbon was recovered from the system. Glucose was added to seawater to stimulate the pathways of glucose metabolism in the oysters. Streptomycin (100 ppm) reduced microbial oxidation of naphthalene and glucose, and reduced bacterial growth. However, even in the presence of streptomycin, microbial oxidation of naphthalene was considerable. The main oxidation product recovered from seawater was ¹⁴CO₂. Radioactivity was also associated with compounds which separated by TLC with 2- and 1- naphthol. The pattern of naphthalene uptake and accumulation in oyster tissues was relatively constant after only a few hours of exposure to naphthalene. The potential of tissues to accumulate naphthalene was shown to be a function of multiple variables such as nutritional state, lipid concentration, length of exposure to naphthalene, and the external naphthalene concentration. Carbon-14-labeled metabolites derived from ¹⁴C-naphthalene were consistently recovered from digests of the oyster tissues. Non-CO₂ alkaline-soluble substances were the primary metabolites. Hexane-extractable substances, which separated by TLC with known standards of 2- and 1- naphthol, were consistently recovered from seawater and tissue digests. It was not possible to conclude that these metabolites were a result of naphthalene metabolism by oyster enzyme systems.     

Comparative study of the carbon cycle in Venus verrucosa fed on bacteria and phytoplankton

Following a previous study, this paper deals with the utilisation of a phytoplankton suspension (Pavlova lutheri) by the clam Venus verrucosa Linné, 1767 as a function of time. Experimental clams filtered and ingested 100% of the suspension after 2 h. The radioactivity recovered in the whole soft body of the clams was 83.8% after 2 h, 66.0% after 10 h and 46.0% after 41 h. The faeces contained 13.7% after 3 h and 34.3% after 41 h. Carbon-dioxide radioactivity (gas plus dissolved) increased slowly to 12.4% after 41 h. When the water was not changed after 17 h, the clams reabsorbed a great part of their dissolved products and faeces. Under these latter conditions the radioactivity recovered from the whole soft body of the clams was roughly the same as that recovered after the start of the experiment. The aim of this study was the comparison of the consumption of two kinds of food: bacteria and phytoplankton. The work was carried out over three years, from 1977 to 1980.     

Gas–liquid chromatography for fenvalerate residue analysis: alterations in the ionic concentration and associated adinosine triphosphatases in fish,Cirrhinus mrigala (hamilton)

In the present study, an attempt has been made to quantify the fenvalerate accumulated in different tissues (gill, muscle and liver) and observe changes involved in the levels of sodium, potassium and calcium ions and Na⁺–K⁺, Mg²⁺ and Ca²⁺ adenosine triphosphatase (ATPase) activities in the freshwater fish, Cirrhinus mrigala on short-term and long-term exposure to the median lethal and sublethal concentration of fenvalerate. Residue analysis using gas–liquid chromatography (GLC) technique revealed that fenvalerate accumulated in highest quantity in gill followed by liver and muscle under median lethal concentration (6?µg?L^?1). Whereas in sublethal concentration (0.6?µg?L^?1), muscle accumulated highest quantity followed by gill and liver, which might be due to the fact that fenvalerate is highly lyphophilic. The ion concentration and ATPase activity were found effected in fish exposed to lethal and sublethal concentrations of fenvalerate. Concentration of Na⁺, K⁺ and Ca²⁺ ions decreased in gill, muscle and liver on being exposed to median lethal concentration to a significant level. Whereas the changes were not highly pronounced at sub lethal level indicating low concentration of fenvalerate and its non-toxic effect at chronic exposure. Na⁺–K⁺, Mg²⁺ and Ca²⁺ ATPases activity were also found decreased in correspondence to the ionic change under median lethal and sub lethal concentrations in target tissues. This might have lead to behavioural changes and create wide-spread disturbance in the normal physiology, ultimately causing the death of the fish. The results suggest that in biomonitoring programmes, ions and associated ATPases can be a good diagnostic tool for fenvalerate toxicity.     

Ameliorated effects of garlic (Allium sativum) on biomarkers of subchronic acrylamide hepatotoxicity and brain toxicity in rats

Acrylamide (ACR) exerts its toxicity through stimulation of the oxidative stress; yet, its effect on neurotransmitter catabolic enzymes has not been elucidated. We investigated the effects of ACR exposure on brain and hepatic tissues antioxidant enzymes activities and different markers such as, acetylcholinesterase (AChE), nitric oxide (NO), monoamine oxidase (MAO), and lipid profile, and to evaluate the protective effects of garlic against ACR toxicity. Male Sprague-Dawley rats were exposed to ACR (1 mg kg^?1 body weight) with or without diet containing 1.5% of garlic powder for 40 days. ACR administration showed a decrease in AChE activity associated with an increase in MAO activity in both brain and hepatic tissues. In addition, ACR administration increased the lipid peroxidation and NO levels of both tissues while decreased the activities of glutathione (GSH), superoxide dismutase, and glutathione-S-transferase (GST). On the other hand, the activities of glutathione peroxidase (GPx) and catalase activities increased as a consequence of GSH depletion after ACR exposure. Finally, ACR exposure increased the brain and liver lipid profile of cholesterol, triglycerides and total lipid, while phospholipids level was decreased. Coadministration of garlic powder with ACR significantly attenuated oxidative stress, MAO activity, and inflammation in brain and hepatic tissues but did not ameliorate AChE activity. In conclusion, our results emphasized the role of garlic as a potential adjuvant therapy to prevent ACR neurotoxicity and hepatotoxicity.     

Brevetoxin exposure in bottlenose dolphins (Tursiops truncatus) associated with Karenia brevis blooms in Sarasota Bay, Florida

Bottlenose dolphins (Tursiops truncatus) face a variety of threats, including risk of exposure to brevetoxins produced by blooms of the harmful alga Karenia brevis. This study investigated brevetoxin exposure in a population of dolphins inhabiting Sarasota Bay, Florida, USA (27°N, 82°W), utilizing tissues from dolphins recovered between 1994 and 2003. Brevetoxin levels detected by ELISA in tissues, gastric samples and excreta from dolphin carcasses (n = 19) associated with K. brevis blooms were compared with with levels in carcasses (n = 16) associated with background K. brevis conditions. In the K. brevis-exposed set, 84% of dolphin carcasses recovered during K. brevis blooms had detectable brevetoxin levels, with values ranging between 7 and 2,896 ng PbTx-3 eq g⁻¹. Over 50% of dolphin carcasses recovered during non-bloom conditions also tested positive by ELISA for brevetoxins, with concentrations ranging from 6 to 44 ng PbTx-3 eq g⁻¹. Control samples from the east coast of Florida were negative by the ELISA. Results from this study establish baseline brevetoxin body burdens in a dolphin population frequently exposed to K. brevis blooms, and data indicate that dolphin carcasses not associated with large-scale mortality events can contain levels of brevetoxins comparable to carcasses stranding during such events.     

Effects of the polychlorinated biphenyl Aroclor® 1254 on the American oyster Crassostrea virginica

Young oysters (Crassostrea virginica) were continuously exposed to Aroclor^® 1254, a polychlorinated biphenyl (PCB), in flowing, unfiltered seawater. Growth rate (height and in-water weight) was significantly reduced (=0.05) in oysters exposed to 5 g/l (ppb) for 24 weeks. Growth rate was not affected in oysters exposed to 1 ppb for 30 weeks. Mortality was not significant in exposed and control groups. In oysters exposed to 5 ppb, greatest PCB residue (whole body) was 425 mg/kg (ppm), 85,000x the concentration in the water, and less than 0.3 ppm was retained after 28 weeks depuration in PCB-free water. In oysters exposed to 1 ppb, greatest residue was 101 ppm, 101,000x the concentration in the water, and less than 0.2 ppm was retained after 12 weeks depuration. Examination of oysters exposed to 5 ppb of this PCB for pathogenesis revealed atrophy of digestive diverticular epithelium and degeneration of vesicular connective tissues concomitant with leukocytic infiltration, but tissue recovery seemed excellent after 12 weeks depuration.Registered trademark, Monsanto Company, St. Louis, Missouri, USA. Mention of commercial products or trade names does not constitute endorsement by the Environmental Protection Agency.Contribution No. 146, Gulf Breeze Laboratory.     

Protein synthesis and growth inOctopus vulgaris

Rates of protein synthesis in the whole body and tissues ofOctopus vulgaris collected in September 1985 and 1986 from the Bay of Naples were measured following a flooding dose injection of³H phenylalanine. There were stable phenylalanine free pool-specific radioactivities and linear incorporation of radiolabel into arm-tip protein from 10 to 30 min after the injection. In starved individuals there were no significant differences between the fractional rates of protein synthesis of the following tissues: ventricle, brain, branchial heart, arm tip, gill, stomach, arm, renal appendage and mantle. The mean value (± SE) for all the tissues was 3.02 ± 0.17% d^–1. In individuals fed varying amounts of crab, resulting in differing growth rates, there was a linear increase in fractional rates of whole-body protein synthesis with growth rate. A standard 148 g octopus growing at 3.0% d^–1 synthesised 0.54 g of protein, with 0.43 g of this protein retained as growth. The proportion of the total protein synthesis which was retained as growth increased with increasing growth rate; at a maximum growth rate of 6% d^–1, over 90% of the protein synthesised was retained as growth. The ventricle, arm tip, gill, arm and mantle also showed similar patterns of a linear increase in fractional rates of protein synthesis with increased growth rates. The RNA concentrations in the whole body and tissues increased with increasing growth rates, but the major change was an increase in the efficiency of translation. It is concluded that rapid growth rates inO. vulgaris are brought about by high rates of protein synthesis and high efficiencies of retention of synthesised protein and, therefore, little protein degradation.     

全氟辛烷磺酸(PFOS)对斑马鱼血浆和组织匀浆中卵黄蛋白原含量的影响

为了研究低剂量的全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)对水生生物的内分泌干扰效应和作用机制,考察了PFOS对斑马鱼(Brachydanio rerio)血浆和组织匀浆中卵黄蛋白原(vitellogenin,VTG)含量的影响。将雄性和雌性斑马鱼分别暴露于0.1、1、10和100μg·L-1的PFOS中进行21d毒性实验,染毒结束后分别检测雄鱼和雌鱼的血浆、头尾组织匀浆液和全鱼匀浆液中的VTG含量。结果显示:(1)PFOS暴露可引起斑马鱼血浆、全鱼和头尾匀浆液中VTG含量的升高,VTG含量的排序为雌鱼(血浆>>全鱼匀浆>头尾匀浆)>>雄鱼(血浆>全鱼匀浆>>头尾匀浆);(2)PFOS暴露所引起的雄鱼血浆和头尾匀浆中VTG含量的升高与剂量呈负相关关系,暴露浓度为0.1μg·L-1时与对照组相比有显著性差异(p<0.05);(3)雌鱼血浆和头尾匀浆中VTG含量的升高与剂量呈倒U型曲线关系,暴露浓度为10μg·L-1时与对照组相比有显著性差异(p<0.05);(4)雄鱼和雌鱼的全鱼匀浆液中的VTG含量与对照组相比均无显著性差异。研究结果表明,PFOS暴露对斑马鱼的内分泌干扰作用明显,其毒性作用机制可能是类雌激素效应,血液和头尾匀浆液中VTG含量能够作为PFOS内分泌干扰效应评价的敏感生物标志物,但响应曲线可能因性别和组织部位的不同有所差异。     

Alterations in Carbohydrate Metabolism in Selected Tissues of Crab, Oziotelphusa Senex Senex (Fabricius) Under Fenvalerate-Induced Stress

Changes in carbohydrate metabolism in hepatopancreas and muscle of the crab, Oziotelphusa senex senex exposed to a sublethal concentration (0.2 ppm) of fenvalerate, a pyrethroid insecticide, were studied. the glycogen and total carbohydrate levels decreased significantly in the tissues of crab exposed to fenvalerate. an increase in phosphorylase 'a' and decrease in aldolase activity levels suggested increased glycogenolysis, and decreased glycolysis during fenvalerate toxicity. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased, suggesting reduced mitochondrial oxidative metabolism. Glucose-6-phosphate dehydrogenase activity was increased significantly, indicating enhanced oxidation of glucose through the hexose monophosphate shunt pathway. Lactate dehydrogenase activity was elevated indicating the development of anaerobic conditions at tissue level in the stressed crab. Cytochrome C oxidase and Mg2+ ATPase activity levels were also decreased, indicating the impaired energy synthesis and prevalence of energy crisis. These results suggest that fenvalerate has a profound effect on the glucose metabolism of crab.     

Evaluation of hemopoietic responses in Labeo rohita Hamilton following acute copper toxicity

Fish are often exposed to highly contaminated water, especially in areas where the dilution rate of waste water is low. Environmental pollutants or other stress may affect one or more of the immunological functions in fish. Effective control of toxic substances is essential for the success of fish culture, which requires fish health monitoring using biomarkers. This study evaluated the effects of heavy metal copper (Cu) at environmentally relevant concentrations on the hematopoiesis in Labeo rohita. L. rohita fingerlings were exposed to different Cu concentrations for 6, 24, 48, or 72 hr. Following exposure, percentage blast cells was found to be increased after 6 and decreased after 24, 48, and 72 hr both at sublethal and LC₅₀ concentrations, whereas percentage mature erythrocytes decreased after 6 and increased after 24, 48, and 72 hr. Erythropoietic and leukopoietic efficiencies were also affected upon exposure. Erythropoietic and leucopoietic efficiencies increased markedly after 6, 24, and 48 hr but decreased after 72 hr in sublethal-treated fish. Erythropoietic efficiency decreased significantly after 6, 24 and 48 hr but increased after 72 hr in LC₅₀-treated fish. Leukopoietic efficiency decreased significantly after 6 hr exposure and increased after 24 and 48 hr but decreased after 72 hr. Flow cytometric studies of head kidney cell cycle phase distribution revealed cell death and DNA synthesis. The percentage cell death increased in fish exposed to sublethal concentrations and rose further at LC₅₀ during the earlier hours of exposure. Synthesis of DNA was increased at sublethal concentrations but was significantly reduced at LC₅₀ dose.     

Biochemical responses of the striped mullet Mugil cephalus to oil exposure I. Acute responses—Interrenal activations and secondary stress responses

Acute single exposures to the water-soluble fraction (WSF) of a No. 2 fuel oil influences several biochemical parameters in juveniles of Mugil cephalus Linnaeus. Plasma cortisol and glucose concentrations were measured at 1 and 3 h after exposure to 1, 5, 10 or 20% WSF. No elevation of plasma cortisol or glucose levels occurred in fish exposed to the lowest concentration of oil, whereas a dose-response relationship was observed at higher doses. The dynamics of plasma corticosteroid, glucose and cholesterol concentrations and osmolality as well as accumulation of naphthalenes in the fish tissues were monitored during exposure to 20% WSF. Circulating cortisol concentrations rose rapidly to 5 times normal values 1h after exposure to oil and subsequently declined to control levels 6 h after oil addition. A smaller secondary rise occurred at 12 h, but cortisol had returned to basal levels 12 h later. In contrast, plasma glucose, cholesterol and osmolality rose more slowly to reach maximum values between 3 and 4 h after oil addition. By 24 h plasma cholesterol and osmolality had returned to normal values whereas the hyperglycemia persisted. However, 72 h after the addition of WSF all biochemical parameters had returned to control levels. At this time considerable accumulation of total naphthalenes had occurred in several fish tissues, whilst the concentration of total naphthalenes in the exposure tanks had declined to background levels. When freshly prepared 20% WSF was added to the exposure tanks during this period, all biochemical parameters were again elevated. The results suggest that the volatile components of fuel oil in the water trigger the biochemical changes described in a dosedependent manner. The possible ecological significance of these changes and the potential use of these parameters as sublethal indicators of environmental contamination are discussed.     

顺式和反式氯丹在家鸡体内的分布和转运

通过工业氯丹口服暴露实验,研究了顺式氯丹(CC)和反式氯丹(TC)在家鸡体内的吸收、代谢、排泄和在各个器官组织内富集的动态过程.分别测定了未暴露个体和一次性暴露后60、120、160、200、300、500、1000和2000min时脑、肝、肠、肌肉、皮、脂肪等组织和器官样品以及胃部和肠道残余物、排泄物中的氯丹含量.研究发现,暴露2000min后,95%以上的氯丹通过代谢途径被消除,只有少量氯丹通过排泄方式被消除;体内氯丹的消除满足一级反应动力学.研究还发现,在代谢过程中,反式氯丹快于顺式氯丹.另外,在吸收和代谢的过程中,有明显的手性特征,(+)-CC和(-)-TC更易被消除,但各个器官组织存在明显差异.     

Fenvalerate-induced macromolecular changes in the catfish,Clarias batrachus

The effects of sublethal concentration of fenvalerate on DNA, RNA, RNA/DNA ratio and protein contents were estimated in gill and kidney tissues of an air breathing fish, Clarias batrachus. Fenvalerate reduced the DNA content in gill, whereas it did not produce any significant effect on DNA in kidney. This tissue-specific change in DNA content may be due to differential effects of fenvalerate or its metabolite(s) on synthesis and/degradation of DNA in gill and kidney cells of the fish. RNA and protein contents declined substantially in both the tissues in response to fenvalerate treatment. However, RNA/DNA ratio remains unchanged. It indicates that decrease in protein content in response to fenvalerate treatment might have been brought about by reduce rate of translation of messenger (mRNA) without a decrease in concentration of ribosomes.     

氰戊菊酯对斑马鱼和稀有鮈鲫不同生命阶段的毒性效应

为探明氰戊菊酯对鱼类不同生命阶段的毒性效应,以斑马鱼和稀有鮈鲫为测试生物,评价了氰戊菊酯对斑马鱼和稀有鮈鲫不同生命阶段的急性毒性差异。研究发现,氰戊菊酯对斑马鱼和稀有鮈鲫胚胎的96 h-LC50值分别为0.901(0.664~1.22)和0.636(0.233~1.74)mg·L~(-1)。氰戊菊酯对稀有鮈鲫胚胎孵化有明显的促进作用,染毒48 h后,0.188和0.375 mg·L~(-1)氰戊菊酯对稀有鮈鲫胚胎的孵化率分别为88.9%和100%。氰戊菊酯对斑马鱼仔鱼、幼鱼和成鱼的96 h-LC50值分别为0.00340、0.0183、0.00487 mg·L~(-1),氰戊菊酯对稀有鮈鲫仔鱼、幼鱼和成鱼的96 h-LC50值分别为0.0520、0.00277、0.00345 mg·L~(-1)。因此,氰戊菊酯对斑马鱼不同生命阶段的毒性从高到低顺序依次为:仔鱼成鱼幼鱼胚胎,氰戊菊酯对稀有鮈鲫胚胎、仔鱼、幼鱼和成鱼的毒性为幼鱼成鱼仔鱼胚胎。试验结果表明,斑马鱼仔鱼对氰戊菊酯的敏感性高于稀有鮈鲫相应的生命阶段,相对于斑马鱼,稀有鮈鲫胚胎、幼鱼以及成鱼对氰戊菊酯的毒性作用更为敏感,说明氰戊菊酯对斑马鱼和稀有鮈鲫不同生命阶段的毒性效应差异较大。     

不同测试方法评估48%毒死蜱乳油对玉米田施药者的人体暴露风险

本研究选取3种不同暴露环境,分别为玉米株高达到施药者膝盖左右(暴露环境1)、达到施药者腰部左右(暴露环境2)和高于施药者身高(暴露环境3),采用手动背负式喷雾器,在这3种暴露环境中施喷48%毒死蜱乳油(EC,稀释500倍),通过贴片法和全身整体测试法(whole body dosimetry,WBD)分析了施药者农药皮肤暴露量(dermal exposure,DE)。依据试验结果,发现在暴露环境1和2中,2种测试方法的农药潜在皮肤暴露量(potential dermal exposure,PDE)无显著性差异,但在暴露环境3中,2种测试方法的PDE之间存在显著性差异(LSD0.05=57.9);对施药者的主要暴露部位进行分析,发现在暴露环境1和暴露环境2中2种测试方法的暴露部位类似,但在暴露环境3中显示,贴片法为手部,全身测试法为上半身(头、颈、前胸、后背及手臂)。使用全身测试法测定PDE同时测定直接皮肤暴露量(actual dermal exposure,ADE),并利用ADE和PDE计算外穿防护服(运动服)渗透率的结果,3种暴露环境分别为4.69%、5.19%和5.54%,比通常假设的防护服或工作服的10%渗透率小。     

Acute toxicity of the synthetic pyrethroid pesticide fenvalerate to some air breathing fishes

Lethal concentrations (LC₅₀) of a synthetic pyrethroid pesticide, fenvalerate, for three species of air breathing fish Clarias batrachus, Channa punctatus and Heteropneustes fossilis were determined under water and acetone soluble condition in the laboratory using the static bioassay procedure of the American Public Health Association (APHA,1995). Acetone soluble fenvalerate was found more toxic than the water-soluble fenvalerate irrespective of species and exposure periods. The LC₅₀ value upon 96 days exposure to acetone soluble fenvalerate for C. batrachus, Channa C. punctatus and Heteropneustes H. fossilis were 1.35, 1.0 and 0.65?µg?L^?1, respectively. It is concluded from the present study that fenvalerate is highly toxic even to the hardy air breathing fishes and the pesticide, when dissolved in water, remains photostable and active to render toxicity for long duration.     

甲基异噻唑啉酮对斑马鱼胚胎的急性毒性和机制研究

甲基异噻唑啉酮(methylisothiazolinone,MIT)作为防腐剂,广泛用于个人护理品、日用品和涂料中。MIT随着污水进入地表水循环,普遍存在于水体中,但目前关于MIT对水生生物毒性的研究还比较少。本文以模式生物斑马鱼的胚胎作为受试对象,评价MIT对斑马鱼胚胎的毒性。将受精后3 h的健康斑马鱼胚胎暴露于梯度浓度的MIT下,观察其对胚胎生长发育的影响,用吖啶橙(AO)染色检测细胞凋亡情况。结果发现,48 h暴露浓度大于1.0 mg·L-1的胚胎孵化被显著抑制,72 h浓度大于1.52 mg·L-1的幼鱼心率显著降低,统计96 h幼鱼死亡和畸形数,并重复验证和计算得到96 h半致死浓度(96 h 50%lethal concentration,96 h-LC50)为6.15 mg·L-1,96 h半致畸浓度(96 h 50%teratogenesis concentration,96 h-TC50)为3.89 mg·L-1,测量96 h胚胎体长,分析最小生长抑制浓度(minimum concentration to inhibit growth,MCIG)为2.31 mg·L-1,AO染色显示72 h胚胎的凋亡细胞主要集中在脑部和尾部。不同时期下镜检观察到,胚胎出现的畸形主要包括尾部发育不良,脊柱弯曲,卵黄囊水肿和心包水肿。此外,高浓度处理组24 h胚胎自主抽动次数增加,72 h和96 h活动能力减弱,触碰反应迟钝。因此,推断MIT对斑马鱼胚胎的发育有较大影响,同时有一定的神经毒性。根据《危险化学品鱼类急性毒性分级试验方法》,判定MIT对斑马鱼胚胎为高毒,该毒性实验结果可为MIT在工业生产和环境中的风险管理提供依据。     

Alterations in Carbohydrate Metabolism in Selected Tissues of Crab,Oziotelphusa Senex Senex (Fabricius) Under Fenvalerate-Induced Stress

Changes in carbohydrate metabolism in hepatopancreas and muscle of the crab, Oziotelphusa senex senex exposed to a sublethal concentration (0.2 ppm) of fenvalerate, a pyrethroid insecticide, were studied. the glycogen and total carbohydrate levels decreased significantly in the tissues of crab exposed to fenvalerate. an increase in phosphorylase ‘a’ and decrease in aldolase activity levels suggested increased glycogenolysis, and decreased glycolysis during fenvalerate toxicity. Krebs cycle enzymes such as NAD-isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were decreased, suggesting reduced mitochondrial oxidative metabolism. Glucose-6-phosphate dehydrogenase activity was increased significantly, indicating enhanced oxidation of glucose through the hexose monophosphate shunt pathway. Lactate dehydrogenase activity was elevated indicating the development of anaerobic conditions at tissue level in the stressed crab. Cytochrome C oxidase and Mg2+ ATPase activity levels were also decreased, indicating the impaired energy synthesis and prevalence of energy crisis. These results suggest that fenvalerate has a profound effect on the glucose metabolism of crab.