苯并(a)芘影响黑鲷肝脏EROD活性变化的动力学研究

研究了黑鲷(Sparusmacro cephalus)在实验生态条件下暴露于不同浓度苯并(a)芘(benzo(a)pyrene,BaP)后,肝脏乙氧基异吩噁唑酮脱乙基酶(EROD)活性在不同暴露时相的动力学变化情况.EROD活性采用动力学方法测定.实验结果表明,暴露于较低质量浓度BaP(0.5,1.0μg/L)黑鲷肝脏的EROD活性在2 d后极显著高于对照组(P<0.01),2.0μg/L组则在2 h后极显著高于对照组,并且随暴露时间的延长,诱导程度表现出不同的下降趋势,而暴露于高质量浓度组(5.0 μg/L)的肝脏EROD活性极显著性诱导出现在12h.总体上较高质量浓度组(2.0,5.0μg/L)EROD活性出现极显著性诱导的时间比低质量浓度组(0.5,1.0μg/L)早,诱导程度也比低质量浓度组的高.在净化实验中各暴露组肝脏EROD活性均下降,与空白对照组比较均没有显著性差异,说明试验浓度没有超出严重损伤肝脏自身恢复系统的范围,在此浓度范围内污染的鱼通过净化可清除BaP污染.     

苯并(a)芘和芘对梭鱼肝脏DNA损伤的研究

用苯并(a)芘、芘以及它们的等量混和物,分别在浓度为0.1,1,10,20,50μg/dm3浓度下对梭鱼暴污,5d后取梭鱼肝脏和鳃用碱解旋法分别测定其DNA的损伤,结果随着污染物浓度的增加,肝脏DNA损伤程度增加;在相同浓度下,苯并(a)芘和芘的联合毒性大于苯并(a)芘和芘分别作用时的毒性之和。所以苯并(a)芘和芘对DNA损伤的联合作用应为加强作用。     

苯并(a)芘和芘对梭鱼肝脏谷胱甘肽过氧化酶活性的影响

在实验生态条件下，浓度范围0.1-50μg/L的苯并（a)芘和芘的短期暴露造成梭鱼肝脏GPx活性先抑制后诱导的效应，相同的污染物，高浓度组对GPx活性的抑制大于低浓度组，出现GPx活性诱导的时间早于低浓度组；相同浓度下，苯并（a）芘对GPx活的作用大于芘，这间接反映了苯并（a）芘和芘的毒性大小，这些结果说明梭鱼肝脏GPx活性与苯并（a）芘和芘暴露有一定的相关性，可以作为海洋环境污染监测的一种生物标志物。     

不同浓度苯并（a）芘对杂色鲍抗氧化酶活性的影响

为阐释不同浓度苯并（a）芘[B（a）P]对杂色鲍（Haliotis diversicolor）的毒性效应,以0.02、0.04和0.08 mg/dm^33个质量浓度的B（a）P对杂色鲍进行水体暴露胁迫,7d后检测肌肉、外套膜、鳃、性腺、肾和肝胰腺的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽S-转移酶（GST）和谷胱甘肽过氧化物酶（GPx）活性及还原型谷胱甘肽（GSH）含量.结果显示：0.02 mg/dm^3的B（a）P暴露对杂色鲍抗氧化系统的影响不明显,而0.04、0.08 mg/dm^3的B（a）P则显著抑制了SOD、CAT和GPx酶活性以及GSH含量,同时对GST酶活性具有显著的诱导作用;实验还发现,不同组织抗氧化酶活性对B（a）P胁迫的敏感性响应存在较大差异,其中鳃、肾脏和肝胰腺的敏感性响应明显高于肌肉和外套膜.上述结果表明,苯并（a）芘暴露对杂色鲍抗氧化酶活性的影响具有明显的剂量-效应关系及组织差异性,杂色鲍的鳃、肾脏或者肝胰腺的抗氧化酶响应多环芳香烃胁迫的更敏感,可作为B（a）P污染的生物标志物.     

苯并（a）芘对大弹涂鱼肝脏超氧化物歧化酶活性的影响

在实验生态条件下，研究了在苯并（a)芘（BaP)胁迫下大弹涂鱼肝脏超氧化物歧化酶（SOD）活性的变化，结果显示：暴露3d时，不同BaP含量组大弹涂鱼肝脏SOD活性无显著差异（P＞0．05），而暴露7d时，随着B aP含量的升高，0.5mg/dm^3 BaP含量组SOD活性被显著诱导（P＜0．05），为对照组的1．87倍；随着暴露时间的延长，各含量组肝脏SOD的活性均表现出不同程度的下降趋势，其中对照组肝脏SOD活性显著降低，表明SOD活性易受污染以外的因素，如水体容量、铒料、光照等的影响。污染解除后，0.5mg/dm^3含量组SOD活性显著升高，表明大弹涂鱼肝脏仍具有较强的生理调节机能，也可能表明SOD活性的变化相对于环境因子改变的“迟滞性”。以上这些结果表明SOD有可能作为大弹涂鱼受BaP胁迫的生物指标。     

鲈鱼胆汁中芘及代谢产物含量与水体中芘含量的关系

运用GC—MS的方法和荧光分光光度法，研究鲈鱼分别暴露于0．1、1．0和10．0μg／dm^3质量浓度芘溶液中7d，水体中芘及其鲈鱼胆汁中芘和1-羟基芘含量的变化,实验结果显示：(1)鲈鱼对水体中的芘具有非常显著的去除作用。(2)随着芘暴露浓度的增大，鲈鱼对芘的代谢去除作用增强。(3)随着暴露时间的延长和芘暴露浓度的增大，胆汁的1-羟基芘浓度递增。(4)鲈鱼胆汁具有较高的芘浓度，对海水中的芘具有较强的富集作用。(5)鲈鱼胆汁的1-羟基芘及芘的浓度与水体芘浓度均具有很好的相关性，对于指示水体的芘污染程度具有一致性；可作为指示水体芘污染程度的生物标志物。     

微塑料和芘对菲律宾蛤仔的毒性效应研究

海洋环境中微塑料和多环芳烃(PAHs)污染日益严重,以滤食动物菲律宾蛤仔(Ruditapes philippinarum)为研究对象,探讨了聚苯乙烯微塑料和芘单一及联合暴露对菲律宾蛤仔的毒性效应.分别采用两个聚苯乙烯微塑料粒径(0.3μm和6μm,20 μg/L)和两个芘浓度水平(10 μg/L和100μg/L)单独和联合暴露21d,测定其对菲律宾蛤仔生理活动(肥满度和摄食率)、免疫防御、氧化应激等相关生物标志物的影响.研究结果表明,除芘单一暴露组外,其余暴露组菲律宾蛤仔的摄食率与对照组相比都显著降低,但这两种污染物对菲律宾蛤仔的肥满度没有显著影响.微塑料和芘暴露均导致菲律宾蛤仔免疫功能受损,表现为血细胞凋亡率增加和吞噬活性被抑制;其中,在小粒径微塑料和高浓度芘存在的暴露组血细胞凋亡率均显著高于对照组,并且二者联合暴露组血细胞凋亡率最高;除大粒径微塑料暴露组外,各暴露组血细胞吞噬活性均显著低于对照组.菲律宾蛤仔抗氧化酶系统不能及时清除体内产生的自由基,导致机体出现氧化损伤现象,表现为抗氧化酶活性变化和丙二醛(MDA)含量升高.微塑料和芘联合暴露导致鳃组织谷胱甘肽疏基转移酶(GST)活性显著升高,消化腺组织过氧化氡酶(CAT)和超氧化物歧化酶(SOD)活性显著降低.综合生物标志物指数(IBR)结果显示,联合暴露对菲律宾蛤仔造成的胁迫压力高于单一暴露组.     

菲、芘、苯并(a)芘单一暴露及分别与α-萘黄酮(ANF)联合暴露对海水青鳉(Oryzias melastigma)胚胎发育毒性效应的比较研究

为了解和探讨3~5环PAHs对海水鱼类胚胎发育的毒性及作用方式,比较研究了菲(phenanthrene,Phe)、芘(pyrene,Py)、苯并(a)芘(benzo(a)pyrene,BaP)单一暴露和三者各自与α-萘黄酮(α-naphthoflavone,ANF)联合暴露对海水青鳉(marine medaka, Oryzias melastigma)胚胎发育的毒性效应。胚胎体内EROD活性、发育畸形、孵化率和心律等毒性指标被测定,结果显示:Phe,Py和BaP对海水青鳉胚胎体内EROD活性的诱导能力大小为BaP>Py>Phe,各化合物对EROD诱导与发育畸形之间的关系较为复杂,除Phe所引起的EROD诱导与畸形指数之间呈显著相关(r=0.95,p=0.015)外,Py和BaP均无相关性;在100 μg/dm3 ANF影响下,CYP1A活性诱导被抑制,但胚胎发育的畸形指数被显著提高,ANF分别与Phe,Py和BaP的联合暴露对胚胎发育呈潜在的协同作用。本文研究初步表明,3~5环PAHs化合物对海水青鳉胚胎发育的毒性作用方式可能不同;CYP1A活性抑制在PAHs混合物对海水青鳉胚胎发育的毒性作用过程中未起到缓解毒性的作用,CYP1A抑制剂与PAH型CYP1A诱导剂的混合物对鱼类胚胎发育具有潜在的协同毒性作用,现有的PAHs混合物毒性风险评价方法可能低估了实际环境中PAHs的风险;海水青鳉早期生活阶段的心脏发育对PAHs混合物暴露较为敏感,可推荐其作为生物标志物指示PAHs或溢油污染。     

苯并[a]芘对雄性褐菖鲉精巢成熟的影响

本实验采用雄性褐菖鲉作为实验对象,腹腔注射0.5×10-6、1×10-6、5×10-6、10×10-6(m/m)苯并[a]芘,7d后苯并[a]芘处理组精巢睾酮水平和睾酮与17β-雌二醇的比值都有上升,但都未表现出显著性差异(P>0.05).腹腔注射50×10-6(m/m)苯并[a]芘,11d后取出精巢,常规石蜡切片,结果显示雄性褐菖鲉的精巢,精小叶腔和输出管中精子密集程度明显增加,次级精母细胞减少,精巢壁厚度变薄.结果提示,苯并[a]芘对褐菖鲉具有类雄激素效应.     

苯并(a)芘对紫菜(Porphyra)的致突变效应

苯并(a)芘(Benzo(a)pyrene)是石油组份中的一种重要的具致癌作用的多环芳香烃化合物。由于燃烧和石油污染等多种原因,在大气、水体和海洋中都能检出它的存在,特别是在海洋中,这种化合物有的沉积于沉积物中,有的被生物体吸收,有的附着在生物体上,有的存在于水体中,因而构成了海洋中一类特殊的污染物。特别引起科学家注意的是这物种质可为某些海洋生物所富集或贮存,并经食物链而最后进入人体。     

EROD activities of liver in Mugil so-iuy exposed to benzo (a)pyrene, pyrene and their mixture

Abstract-The effects on hepatic EROD (7-ethoxyresorufin O-deethylase) in Mugil so-iuy exposedto benzo(a)pyrene (BaP), pyrene and their mixtures of equal concentration were investigated, at con-centrations of 0.1, 1.0, 5.0, 10.0, 50.0 μg/dm~3, in experimental condition. Time-effects and dose-response of the biochemical indexs were observed. The results showed that the hepatic EROD activitieswere induced by the exposure of BaP, pyrene and their mixtures at high concentration. Dose-responseconnections were that the hepatic EROD activities were elevated with increasing concentration of the pol-lutants. The combined effect of BaP and pyrene at 1:1 concentration ratio on hepatic EROD activity wasantagonism.     

Accumulation and effects of benzo(a)pyrene on cytochrome P450 1A in waterborne exposed and intraperitoneal injected juvenile turbot (Scophthalmus maximus)

Juvenile turbot (Scophthalmus maximus) were exposed to benzo(a)pyrene (BaP) for 14 d using a glass bead generator flow-through system. Exposure was followed by a recovery period of 16 d. The highest BaP concentration in the edible portion of the fish, 16.5 ± 4.3 μg BaP/kg, was observed on the first day. Then concentrations dropped following first-order kinetics. BaP was below detection level at the end of the experiment. A statistically significant increase in bile fluorescence was observed from day 9 until the end of the experiment, suggesting the elimination of BaP metabolites by this route. No significant differences between control and exposed fish in EROD activity and CYP1A concentration, measured by immunodetection method, were observed. Intraperitoneal injection of 2.5 mg BaP/kg in juvenile turbot induced EROD activity. Under waterborne experimental conditions, bile fluorescence was observed to be a more sensitive biomarker of BaP exposure than EROD activity and CYP1A measurement.     

海水中多环芳烃的暴露浓度对鲈鱼体内脂质过氧化程度的影响

本文以鲈鱼为实验材料，以鲈鱼体内的丙二醛含量为指标研究了在水样中16种多环芳烃组分和外加芘为实验试剂的条件下，鲈鱼体内不同器官、组织的脂质过氧化程度的变化．实验结果表明：（1）在鲈鱼鳃、全血中的丙二醛浓度较高，而肝脏的丙二醛浓度较低。（2）水样中多环芳烃及外加芘的暴露能导致鲈鱼肝的丙二醛浓度升高，这表明多环芳烃以及芘的暴露能引起鲈鱼肝内脂质过氧化程度的提高。（3）水体中多环芳烃及外加芘浓度的变化对鲈鱼肝的丙二醛浓度的影响具有可逆性，且鲈鱼肝的丙二醛浓度与水环境的多环芳烃（包括芘）暴露浓度呈良好的正相关关系。这说明：鲈鱼肝的丙二醛浓度可作为指示水环境的多环芳烃污染程度的指标。由于生物体内的丙二醛浓度受多种因素的影响，在使用丙二醛浓度指标来指示海洋环境的多环芳烃污染时。最好与其他指标配合使用，以更准确地指示海洋环境多环芳烃污染。     

The Japanese medaka (Oryzias latipes) model: applicability for investigating the immunosuppressive effects of the aquatic pollutant benzo[a]pyrene (BaP)

Despite the fact that BaP is a carcinogen, mammalian immunosuppressant, and ubiquitous aquatic pollutant, knowledge regarding the effects of BaP on the immune system of fish is still lacking. To begin to fill this gap, studies were conducted in medaka to examine the effects and mechanisms by which BaP exposure might alter host immunocompetence. Fish, exposed by IP injection of BaP (2-600 microg/g BW), were examined after 48 h for effects upon immune function and CYP1A expression/activity. Benzo[a]pyrene, at a concentration below that which increased levels of CYPIA expression/activity (2 microg BaP/g BW) suppressed lymphocyte proliferation. Concentrations of BaP at 20 and 200 microg/g BW. suppressed antibody-forming cell (AFC) numbers, superoxide production, and host resistance against bacteria. In contrast, exposure to the low affinity aryl hydrocarbon receptor (AhR) agonist, benzo[e]pyrene (BeP), neither induced CYP1A expression nor altered immune function. Given the lack of immunosuppressive effects produced by BeP, and the fact that exposure to the AhR antagonist (and CYP1A inhibitor) alpha-naphthoflavone (ANF) ameliorated the suppressive effects of BaP upon AFC numbers, the AhR pathway (including CYP1A-mediated production of reactive BaP metabolites) appears important in mediating BaP-induced immunotoxicity in fish, as in mammals. In the past, the medaka has proven a successful model for assessing carcinogenic agents. These studies have demonstrated its utility for also determining the immunosuppressive effects of an important aquatic contaminant.     

In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish.

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.     

Response of the mixed-function oxidase system to toxicant dose, food and acclimation temperature in the bluegill sunfish

The degree of induction of hepatic mixed function oxidase (MFO) enzymes in fish is modulated by environmental conditions. This study was designed to investigate the influence of water temperature, presence or absence of food, and exposure to benzo(a]pyrene (BaP) on the inductive response of bluegill sunfish (Lepomis macrochirus). The results show an increase in 7-ethoxyresorufin O-deethylase (EROD) activity with an increase in acclimation temperature and dose. This activity appears to be associated with a very small fraction of the total cytochrome P-450 induced. Major changes were observed in the 53- and 57-kilodaltons (kDa) electrophoretic bands.     

Paralytic shellfish poisoning toxins induce xenobiotic metabolising enzymes in Atlantic salmon (Salmo salar).

Paralytic shellfish poisoning (PSP) toxins have been implicated as the causative agent of a number of fish kills. Exposure experiments indicate that fish are susceptible to PSPs by intraperitoneal (i.p.) and oral administration, while sampling of fish affected by toxic blooms reveals that these toxins can be accumulated. In spite of the potential impact to marine fisheries, little research has been conducted on the potential metabolism and detoxification of PSPs in marine fishes. Previous work by this group has shown that the xenobiotic metabolising enzyme (XME) cytochrome P-450 (CYP1A) is induced in Atlantic salmon (Salmo salar) following i.p. exposure to saxitoxin (STX). Salmon injected i.p. with sub-lethal doses of STX show a four- to eight-fold induction of hepatic CYP1A (as shown by ethoxyresorufin-O-deethylase activity) over controls after 96 h. Results presented here show that the phase II XME glutathione S-transferase (GST) is also induced in salmon following PSP exposure. Post smolts were exposed to three injections of PSPs (2 micrograms STXeq/kg) over 21 days. Injection of both STX and PSPs extracted from a toxic strain of dinoflagellate (Alexandrium fundyense, CCMP 1719) resulted in induction of hepatic GST, as measured by activity for 1-chloro 2,4-dinitrobenzene. Such inductions indicate a potential role for XMEs in PSP metabolism. Possible roles for other enzymes are also discussed.