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1.
The objective of this study was to determine if tamoxifen or an aromatase inhibitor (4-hydroxyandrostenedione; 4-OHA) affected plasma concentrations of o,p′-DDT and its metabolites, o,p′-DDD and o,p′-DDE, in mature tilapia. Male and female tilapia were injected 6 times intraperitoneally with o,p′-DDT (40 mg/kg) alone or in combination with 4-OHA (2 mg/kg) over a 12 day period. An additional group of male fish was injected with tamoxifen (5 mg/kg) plus o,p′-DDT. At the end of the treatment period, plasma samples were extracted and analyzed by GC/ECD. Females injected only with o,p′-DDT had significantly higher levels of o,p′-DDT compared with males. Interestingly, females and males treated concomitantly with o,p′-DDT and 4-OHA or tamoxifen had significantly lower concentrations of plasma o,p′-DDT (about 50%) compared with fish treated with only o,p′-DDT. These initial results suggest that an interaction between endocrine-active compounds occurs in vivo in tilapia and may involve alterations in metabolism of o,p′-DDT.  相似文献   

2.
In order to investigate the mechanism by which o,p'-DDT disrupts endocrine functioning of Nile tilapia in vivo, the estrogenicity of o,p'-DDT was investigated in conjunction with 17beta-estradiol (E2) and tamoxifen. Mature, male tilapia were treated intraperitoneally with o,p'-DDT (60 mg/kg, one dose) or E2 (5 mg/kg, four doses) in the presence or absence of tamoxifen (5 mg/kg, six doses) for 12 days and then plasma vitellogenin (Vtg) (measured as alkaline-labile phosphorous), E2, and testosterone (T) were measured. Vtg levels were increased dramatically by E2 (1,744 +/- 171 microg/ml) and moderately by o,p'-DDT (82 +/- 15 microg/ml) compared with controls (23 +/- 3.5 microg/ml). Tamoxifen alone had no effect on Vtg production, but inhibited both E2 and o,p'-DDT stimulated vitellogenesis. T levels were reduced with E2 administration (1,688 +/- 383 pg/ml) and declined further with the combined treatment of E2 and tamoxifen (281 +/- 70 pg/ml), compared with controls (6,558 +/- 1,438 pg/ml). Tamoxifen or o,p'-DDT alone did not affect T levels, but their combined treatment did (2,069 +/- 647 pg/ml). The results of this study suggest that o,p'-DDT is weakly estrogenic in male tilapia, and that this activity may be mediated through the estrogen receptor.  相似文献   

3.
In order to simulate a possible natural administration route of xenoestrogens male flounder Platichthys flesus were exposed via the diet to the alkylphenol 4-tert-octylphenol. Treatment with 4-tert-octylphenol (10, 50 and 100 mg OP kg(-1) BW) or 17beta-estradiol (0.05 mg kg(-1) BW) every second day during a period of 11 days resulted in a significant increase in plasma vitellogenin (Vtg) concentrations. The induction of Vtg was greatest in the fish receiving 50 mg OP kg-' BW. A significant accumulation of 4-tert-octylphenol was found in liver and muscle tissue of the OP treated groups. The tissue concentrations of 4-tert-octylphenol and the plasma vitellogenin concentration were positively correlated. The results show that 4-tert-octylphenol accumulates in liver and muscles of flounder P. flesus, and exerts estrogenic effects such as vitellogenin induction.  相似文献   

4.
外源激素对养殖牙鲆血浆睾酮和雌二醇含量的影响研究   总被引：7，自引：0，他引：7  
雄性牙鲆单独注射促黄体激素释放激素类似物(LHRH-A)(每千克质量的注射量,下同)25μg/kg或人绒毛膜促性腺激素(hCG)1 000 IU/kg,血浆睾酮(T)含量在注射后6 h大幅度降低,12h时达到最低值,以后逐渐回升;LHRH-A与hCG联合注射[LHRH-A(12.5μg/kg)+hCG(500 IU/kg)],注射后6 h血浆T含量剧烈下降,24 h时达到最低点,以后缓慢回升;对照组雄鱼血浆T含量随着采样进行而呈现降低趋势.雌鱼单独LHRH-A后,血浆雌二醇(E2)水平逐渐下降,24 h时达到最低值,30 h后略有回升;单独注射hCG后,血浆E2含量缓慢下降,30 h达到最低值;LHRH-A与hCG联合注射,注射后6 h血浆E2含量逐渐下降,24 h时达到最低点,30 h时缓慢回升.对照组雌鱼血浆E2水平也随着采样的进行而逐渐降低.结果表明:单独或联合注射LHRH-A和hCG降低了雌、雄牙鲆血浆E2和T含量,与对照组结果相同.  相似文献   

5.
In order to investigate the mechanism by which o,p′-DDT disrupts endocrine functioning of Nile tilapia in vivo, the estrogenicity of o,p′-DDT was investigated in conjunction with 17β-estradiol (E2) and tamoxifen. Mature, male tilapia were treated intraperitoneally with o,p′-DDT (60 mg/kg, one dose) or E2 (5 mg/kg, four doses) in the presence or absence of tamoxifen (5 mg/kg, six doses) for 12 days and then plasma vitellogenin (Vtg) (measured as alkaline-labile phosphorous), E2, and testosterone (T) were measured. Vtg levels were increased dramatically by E2 (1744±171 μg/ml) and moderately by o,p′-DDT (82±15 μg/ml) compared with controls (23±3.5 μg/ml). Tamoxifen alone had no effect on Vtg production, but inhibited both E2 and o,p′-DDT stimulated vitellogenesis. T levels were reduced with E2 administration (1688±383 pg/ml) and declined further with the combined treatment of E2 and tamoxifen (281±70 pg/ml), compared with controls (6558±1438 pg/ml). Tamoxifen or o,p′-DDT alone did not affect T levels, but their combined treatment did (2069±647 pg/ml). The results of this study suggest that o,p′-DDT is weakly estrogenic in male tilapia, and that this activity may be mediated through the estrogen receptor.  相似文献   

6.
An ELISA for cod vitellogenin (VTG) has been set up using cod lipovitellin for plate coating and standardisation. The assay has been applied to plasma samples collected from male and female cod caught in three distinct areas around the UK, three areas off the Norwegian coast and also to cod reared initially at an aquaculture site and subsequently maintained at a research station. The aim of the study was to determine whether there were any signs of oestrogenic endocrine disruption in a fish species living offshore. VTG induction was found in male cod caught in the North Sea, the Shetland Box area, in Oslofjord and also in cultivated fish. There was a strong relationship between concentrations of VTG and fish size. There was no evidence that the presence of VTG in the plasma of males is a natural part of their life cycle. On the other hand, the size of fish at which these elevated VTG concentrations appear (ca. 5 kg) is about the size that cod change from feeding primarily on benthic invertebrates to mainly other fish, both benthic and pelagic. The possibility is suggested that large cod pick up oestrogenic endocrine disrupters through the food chain.  相似文献   

7.
The role of vitellogenin in the transport of organochlorines was investigated in Atlantic croaker (Micropogonias undulatus) by exposing them through the diet to o,p′-DDT at a concentration of 10.8 μg/100 g fish/day for 14 days or Aroclor 1254 (PCB) at a concentration of 0.5 mg/100 g fish/day for 30 days during gonadal recrudescence. Tissue samples were taken from the fish at various times after initial exposure, and o,p′-DDT and PCBs were extracted in acetonitrile and analyzed by gas chromatography. Analysis of the ovarian tissue collected 2 and 3 weeks from the start of exposure revealed that the o,p′-DDT concentration increases as the gonadosomatic index (GSI) increases (r2 = 0.63), with accumulation ranging from less than 1% to as much as 8% of the total dosage. Interestingly, o,p′-DDT did not accumulate in the testes during the same exposure period. Accumulation of PCBs was found to be 40 times higher in the ovaries than in the testes. Gel filtration of plasma from exposed females showed that o,p′-DDT elutes in the low density lipoprotein and vitellogenin fractions. Control plasma incubated with o,p′-DDT at 4 °C for 16 h followed by chromatography on Sepharose 6B gave similar results with an o,p′-DDT concentration of 0.6μg/mg protein in the vitellogenin fraction. Furthermore, both o,p′-DDT and PCBs were found to bind to purified croaker vitellogenin. These results suggest that lipoproteins, including vitellogenin, are involved in the transport and accumulation of organochlorines in the ovaries of exposed fish.  相似文献   

8.
We conducted studies to determine if the xenoestrogens Surflan and its active ingredient oryzalin, affect indices of reproductive fitness in medaka (Oryzias latipes). Oryzalin (0.5, 0.25mg/l) or Surflan (2.0 microl/l) and oryzalin (0.5mg/l) significantly increased the mean number of non-fertilized eggs produced by treated females paired with untreated males, or by untreated females paired with treated males. Oryzalin (1.0, 0.5, 0.25mg/l) and Surflan (3.8, 2.0, 1.0 microl/l) significantly affected the time to hatch of eggs from treated females paired with untreated males, and from untreated females paired with treated males. Surflan (3.8, 2.0, 1.0 microl/l) induced intersex lesions in 80-100% of males. Oryzalin-exposed males exhibited a significant increase in the incidence of necrotic spermatids and necrotic spermatogonia, while oryzalin-exposed females had significantly fewer immature oocytes and an increase in the occurrence of hyperplastic ovaries. Our results indicate that Surflan and oryzalin affect both reproduction and gonadal histology in male and female medaka.  相似文献   

9.
Vitellogenin (Vtg) is a yolk protein precursor that has been identified as a sensitive biomarker for exposure to estrogenic compounds. We evaluated specific monoclonal and polyclonal antibodies for reactivity with plasma Vtg from two Australian Perciformes, the tropical barramundi (Lates calcarifer) and the temperate black bream (Acanthopagrus butcheri). Blood plasma from 17beta-estradiol exposed (E2) male barramundi (20 mg kg(-1)) and male black bream (2.5-5.0 mg kg(-1)) were sent to Biosense Laboratories (Norway) for cross-reactivity testing using their extensive anti-Vtg antibody selection. Indirect ELISA results determined barramundi plasma displayed the highest binding affinities to ND-3G2 (monoclonal-Mab) and PO-1 (polyclonal-Pab). Black bream was most cross-reactive with ND-1C8 (Mab) and PO-2 (Pab). Next, plasma was assessed for Vtg induction in E2-dosed (5 mg kg(-1)), hatchery-reared barramundi and black bream versus a non-injected control group. Vtg production was assessed by Western blot and indirect ELISA using ND-3G2 and ND-1C8 Mabs, respectively. A prominent band was identified in the range of 100-200 kDa for all female black bream and for all E2-treated barramundi and black bream males, which was confirmed as Vtg by Western blot. Indirect ELISA results for barramundi demonstrated highly significant differences in E2-dosed fish as compared to control fish (Student t, P<0.001). E2 male black bream were significantly different than control males (Student t, P<0.001) and control and E2 females displayed highly significant differences (Student t, P<0.001). These results indicate that exposure to 17beta-estradiol induces significant Vtg production in males of the two Australian Perciformes, with potential use as a biomarker for exposure to estrogenic compounds.  相似文献   

10.
Dab (Limanda limanda) caught in UK offshore waters show evidence of being exposed to estrogenic endocrine disrupters at a relatively low level. Two of 449 males caught between June and July 2005 had markedly elevated levels of vitellogenin (VTG; 21 and 750 microg/ml) and the remainder ranged from <0.01 to 8.6 microg/ml. Omitting the two outliers, there was a very significant positive relationship with the mass of individual males (a feature noted in previous studies on cod). Mean VTG concentrations in males differed significantly between sites. The site with the highest mean (1.6 microg/ml) was North East of the Dogger Bank and the site with the lowest (0.04 microg/ml) was in Cardigan Bay. Mean VTG concentrations in all North Sea fish were significantly higher than English Channel and Irish Sea fish, but this difference disappeared when fish mass was taken into account. VTG concentrations showed no relationship to water depth, stage of sexual maturity or age of the males. Sixty selected male plasmas were assayed for 17beta-estradiol but only two had measurable amounts (assay limit 0.04 ng/ml). Despite being the start of summer, the gonads of many of the males and females (especially those caught in the North Sea) showed signs of sexual maturity (presence of sperm in males and vitellogenic eggs in females). Many females had high VTG concentrations (up to 14 mg/ml) and 78 out of 80 had measurable concentrations of 17beta-estradiol. The cause of elevated VTG levels in male dab is unknown. As seen in cod, the presence of affected males does not appear to be linked to proximity to land or to known point sources of endocrine disrupters. However, our data, showing that larger fish are more likely to have elevated VTG concentrations, suggests a gradual accumulation by marine fish, probably through feeding, of persistent (probably relatively weak) estrogenic compounds.  相似文献   

11.
海水养殖罗非鱼补偿生长的生物能量学机制   总被引：12，自引：4，他引：12  
王岩 《海洋与湖沼》2001,32(3):233-239
1998年4月28日—6月24日和5月20日—7月14日分别在汕头大学南澳海洋生物实验站研究了杂交罗非鱼停喂(简称绝食)或限量投喂(简称限食)后的补偿生长，探讨了杂交罗非鱼补偿生长的生物能量学机制。结果表明，海水养殖杂交罗非鱼在饱食状态下的能量收支为100C=32.8G+50.8R+15.3F+1.1U。在恢复生长期间，对照鱼的食物能和代谢能高于绝食鱼或限食鱼，但其单位体重的食物能、代谢能、生长能、粪能和排泄能均明显低于补偿生长的绝食鱼或限食鱼，绝食或限食后海水养殖杂交罗非鱼的能量收支模式未发生明显变化。  相似文献   

12.
采用6种等蛋白质(34.4%)、等能量(16.10MJ/kg)试验日粮,研究了尼罗系吉富罗非鱼幼鱼实用日粮中蔗糖糖蜜替代小麦次粉的养殖效果与血糖代谢变化。结果表明,56d试验期间各试验组鱼均无死亡;蔗糖糖蜜替代小麦次粉40%—100%日粮组鱼的摄食量、特定生长率、饲料效益和蛋白效益均高于小麦次粉组鱼,当蔗糖糖蜜100%替代小麦次粉时,其摄食量、特定生长率和饲料效益蛋白效益比均显著性上升(P<0.05)。各试验组鱼鱼体营养成分(蛋白质、脂肪、灰分和水分)和肝体指数无显著性差异(P>0.05),肝脏结构正常。蔗糖糖蜜组鱼血浆中血糖、总蛋白、胆固醇、甘油三酯含量明显高于小麦次粉组鱼(P<0.05)。本试验结果认为,蔗糖糖蜜在尼罗系吉富罗非鱼幼鱼实用日粮中可以完全替代小麦次粉,蔗糖糖蜜对尼罗系吉富罗非鱼幼鱼具有较好的生长效益、节约日粮蛋白质效益和适口性,其主要原因与摄食蔗糖糖蜜后尼罗系罗非鱼幼鱼产生的较长时间高血糖现象有关。  相似文献   

13.
在模拟受控条件下,利用气相色谱方法研究分析了4种酞酸酯类化合物在龙须菜(Gracilaria lemane-iformis)-篮子鱼(Siganus oramin)食物链中的积累、分布和放大状况。结果表明,4种酞酸酯在龙须菜组织内的积累表现为:邻苯二甲酸二异辛酯(DEHP)>邻苯二甲酸二丁酯(DBP)>邻苯二甲酸二乙酯(DEP)>邻苯二甲酸二甲酯(DMP)。侧链最长的DEHP在龙须菜藻体内的含量随暴露时间的延长呈增加的趋势,30 d体内积累量可达2.35 mg/kg(鲜质量);侧链最短的DMP在龙须菜藻体内的质量比随时间变化差异不显著,约为0.05 mg/kg;在30 d的暴露中,4种酞酸酯DMP,DEP,DBP和DEHP在篮子鱼体内总质量比分别为0.08,0.41,1.72,3.11 mg/kg。其中DBP和DEHP在鱼内脏组织中有较高的积累和分布,分别为1.14 mg/kg和1.83 mg/kg,其次为鱼残体组织,肌肉组织中含量最低。DEHP和DBP在龙须菜和篮子鱼体不同组织中均有一定程度的富集(生物富集系数FBC均大于1)。其中DEHP和DBP在内脏组织中的FBC值分别高达9.16和5.68,在龙须菜-篮子鱼这个简单食物链传递中DEHP和DBP在篮子鱼内脏组织中存在放大现象。  相似文献   

14.
Sediments and organisms were examined for concentrations of organic and metal contaminants from near the Los Angeles County (JWPCP) municipal outfall at Palos Verdes (PV) station 7-3, the Los Angeles City (Hyperion) municipal outfall at Santa Monica Bay (SMB) station 6-4 and reference station SMB 2–3 near Malibu Beach. Flows and mass emission rates of suspended solids, PCBs, Cd and Zn were similar at the two outfalls. Mass emission rate of copper was almost twice as high from Hyperion as from JWPCP, while mass emission rate of DDTs was an order or magnitude higher from JWPCP than from Hyperion.Surficial sediments at PV 7-3 were enriched in most contaminants relative to SMB 6-4 and relative to the mass emission rates of contaminants from the JGVPCP and Hyperion outfalls. Some of this enrichment could be accounted for by the greater accumulation of organic material, measured as total volatile solids, at PV 7-3 relative to SMB 6-4. Some might be accounted for by resurfacing of more contaminated historical deposits buried at PV 7-3. Some of the enrichment of DDTs relative to PCBs could be accounted for by the greater abundance of oxygenated metabolites of PCBs (PCBols) relative to DDTs (DDTols) in sediments.The degree of contamination of organisms by DDTs increased with proximity to PV 7-3 but contamination by PCBs was similar at PV 7-3 and SMB 6-4. DDT concentrations in fish livers ranged from 12 ± 4 ( ) mg/wet kg in longspine combfish from SMB 2–3 to 610 ± 105 (n = 5) mg/wet kg in Pacific sanddab from PV 7-3. DDT concentrations in fish gonads ranged from 0·003 ± 0·003 (n = 5) mg/wet kg in yellowchin sculpin from SMB 6-4 to 1.5 ± 6 (n = 3) mg/wet kg in Pacific sanddabs from PV 7-3. PCB concentrations in fish livers ranged from 1·2 ± 0·4 (n = 4) mg/wet kg in yellowchin sculpin from SMB 2–3 to 16 ± 3 (n = 6) in Pacific Sanddab from SMB 6-4. DDT and PCB concentrations in invertebrate hepatopancreas were only slightly lower than those in fish livers. DDTols and PCBoIs comprised an average of 91 % of the total of parent compounds and oxygenated metabolites in sediments and 66 % in livers and hepatopancreas. Trace metals were frequently decreased in livers and hepatopancreas from near outfalls even though they were highly elevated in sediments.Comparison of sediment and tissue chlorinated hydrocarbon data with that from Elliot and Commencement Bays, Puget Sound, indicated that none of the southern California coastal stations considered in this study were sufficiently lacking contamination to be considered as adequate control sites.  相似文献   

15.
本文旨在探讨肌肉注射不同浓度的紫锥菊提取物对大菱鲆(Scophthalmus maximus)的非特异性免疫功能的影响,试验选取体重(250±20)g的大菱鲆作为试验动物,分别注射10、20、40mg/m L浓度的紫锥菊提取物,试验共进行28d,每隔7d采集血液测试非特异性免疫指标,第28天用迟缓爱德华氏菌(Edwardsiella tarda)攻毒,连续观察7d,测定其免疫保护率。结果显示肌肉注射紫锥菊提取物对大菱鲆超氧化物歧化酶(SOD)活力和溶菌酶活力(LSZ)的影响极显著(P0.01);对吞噬细胞吞噬率(PP)的影响显著(0.01P0.05),对吞噬细胞呼吸爆发活力的影响极显著(P0.01)。攻毒试验表明,紫锥菊提取物能够降低迟缓爱德华氏菌攻毒后鱼的死亡率,提高其免疫保护率,尤其是40mg/m L组。本试验研究表明,紫锥菊提取物能显著的提高大菱鲆的非特异性免疫功能,且以注射浓度40mg/m L的效果最好。  相似文献   

16.
王建钢 《海洋与湖沼》2013,44(4):1108-1114
采用单因子实验设计方法, 进行了饲料中添加维生素C对美国红鱼生长(平均增重率、存活率、特定生长率、饲料效率)和免疫反应[血清中溶菌酶活性、血清总补体活性和超氧化物岐化酶(SOD)活性]影响的研究。结果表明: 随着饲料中维生素C添加水平由0提高到100mg/kg时, 美国红鱼的增重率和特定生长率显著提高。以特定生长率为指标, 美国红鱼最佳生长性能的饲料维生素C添加量为104.5mg/kg左右; 饲料中维生素C水平在0—98.9mg/kg时, 美国红鱼肌肉和肝脏中维生素C的积累量随饲料中维生素C的增加而显著增加(P<0.05); 美国红鱼获得最大肝脏和肌肉中维生素C的积累量时饲料中维生素C最低添加量为128.1和104.0mg/kg; 美国红鱼血清溶菌酶和血清总补体活性在维生素C添加水平分别为98.9和198.7mg/kg时达到最高值, 随后变化不明显; 美国红鱼血清SOD活性随维生素C添加水平的增加而显著升高, 并且活性在198.7mg/kg达到最高值, 随后显著下降。综上所述, 美国红鱼维生素C生长和免疫的维生素C适宜添加水平为200mg/kg左右。  相似文献   

17.
Benzo[a]pyrene (BaP), a procarcinogenic polycyclic aromatic hydrocarbon (PAH), is bioactivated to BaP diol-epoxides (BPDEs) that can form adducts with DNA and blood proteins. We report here for the first time the in vivo formation of adducts between BPDE and plasma albumin (Alb) from two fish species experimentally exposed to BaP. Brook trout (Salvelinus fontinalis) received either a single i.p. dose (10 mg/kg) or two separate i.p. doses (25 mg/kg; 7 days apart) of BaP, and blood was collected 2 (single exposure) or 3 (multiple exposure) days post-treatment. Arctic charr (Salvelinus alpinus) received 10 i.p. doses (3 mg/kg; a single dose every 6 days), and blood was collected 2 days after the second, sixth, and 10th injections. BPDE-Alb adducts were measured by an improved HPLC/fluorescence method developed to detect and quantify BaP-tetrols released after acid hydrolysis of adducted Alb. HPLC/fluorescence chromatograms of Alb from BaP-treated fish revealed only BaP-tetrol I-1, thus indicating the formation of adducts exclusively via the (+)-anti-BPDE metabolite. Levels of (+)-anti-BPDE-Alb adduct ranged from 0.68 to 19.6 ng of tetrol I-1 per gram of Alb. Notably, adduct level was not related to BaP dose and there was no accumulation of adducts with repeated exposure, which may indicate a very short half-life (< 2 days) of plasma Alb in fish. The data suggest that BPDE-Alb adducts in fish could be useful as a non-destructive biomarker of recent exposure to bioactivated BaP.  相似文献   

18.
Previous experiments demonstrated that exposure of mummichog to cadmium (Cd) in combination with benzo[a]pyrene (BaP) caused a higher mortality than would be expected from simple additive effects. Experiments are described here that investigated whether BaP exposure inhibits the induction of metallothionein (MT), a major detoxifying protein for Cd, or if reactive BaP metabolites compete with Cd for binding sites on MT. Fish were injected with or without BaP (18 mg/kg) in combination with a low (1 mg/kg) or high (3.2 mg/kg) dose of Cd, and in one treatment BP was dosed 4 days after Cd. The results showed a rapid induction of MT to 1.5 mg/g wet weight liver, 1 day after injecting the low Cd dose. Simultaneous BaP exposure significantly delayed the induction of MT, for both low and high Cd doses, and BaP temporarily lowered the induced MT concentration when dosed 4 days after induction by Cd. To test if binding of BaP metabolites to MT reduces the detoxification potential for Cd, microsomes of CYP1A-induced fish were incubated with MT and radiolabeled BaP. Active metabolism of BaP was observed by high-performance liquid chromatography analysis, but no association of BaP metabolites with MT was found. Neither could this be demonstrated in vivo, in liver MT isolated from mummichog dosed with 3H-BaP and Cd. These results suggest that increased toxicity of Cd in combination with BaP exposure is likely to be caused by inhibited MT synthesis, rather than by interference of BaP metabolites with Cd binding on MT.  相似文献   

19.
Environmental contamination may be one cause of the high level of parasitic infections and high death rates of eiders in the Wadden Sea where, among other contaminants, high concentrations of polychlorinated biphenyls (PCBs) occur.To study this problem, four-week-old eider ducklings were exposed to single doses of 3,3′,4,4′-tetrachlorobiphenyl (CB 77; 5 or 50 mg i.p./kg) or Clophen A50 (50 or 200 mg i.p./kg). The control group was injected with corn oil only (5 ml/kg). A dose-dependent induction of the hepatic monooxygenase system was only found in ducklings treated with CB77. Clophen A50 (Clo A50) showed no effect.Comparison of CB patterns in the Clo A50-injected groups with the original mixture revealed differences associated with molecular structure: only CBs with vicinal hydrogen atoms in the meta- and para-positions had  相似文献   

20.
Benzothiazole, a common chemical associated with tire manufacturing and industrial wastewater, is a principal component of both fresh water and estuarine tire leachate, a neurotoxicant to larval sheepshead minnows (Cyprinodon variegatus) in in vivo estuarine studies. The neurotoxic potential of benzothiazole was investigated following in vivo and in vitro exposure of sheepshead minnows to 3.75, 7.5, 15, 30 and 60 mg/l benzothiazole. Following benzothiazole exposure, fish were evaluated for survival, growth and histological alterations. Fish mortality occurred after 5 days of exposure to 60 mg/l (LC50 = 41.9). Significant decreases in larval growth were noted at all concentrations. Histologically, gills had cellular alterations but the central nervous system lacked the severe cellular damage seen in previous tire leachate exposure studies. Benzothiazole cytotoxicity to primary cultures of brain cells from sheepshead minnow and tilapia (Oreochromis niloticus) and two epithelial cell lines was evaluated using a tetrazolium salt assay (MTT) at 1 and 4 days. In vitro results indicate primary cultures of brain cells are less sensitive to benzothiazole than epithelial cell lines. Significant cytotoxicity to the epithelial cell lines was noted at 30 and 60 mg/l concentrations. Histologically and cytotoxicologically, the present study indicates that benzothiazole is a gill toxicant and not a neurotoxicant.  相似文献   

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