久效磷对秀丽隐杆线虫运动、学习和觅食行为的影响

久效磷(MCP)是一种广谱类内吸附性有机磷农药和潜在的神经毒剂,能够对非靶生物产生神经毒性作用,而行为毒性是神经毒性的主要表现形式. 以运动、学习与觅食行为、乙酰胆碱酯酶活性为指标,研究了久效磷对非靶生物——秀丽隐杆线虫(Caenorhabditis elegans,下称线虫)行为的影响. 结果显示:经0.5、5.0和50.0 mg/L久效磷暴露后,各暴露组线虫头部摆动和身体弯曲频率均极显著降低,0.5 mg/L暴露组线虫向前摆动频率显著减少,5.0和50.0 mg/L暴露组线虫向前摆动频率极显著减少;5.0和50.0 mg/L暴露组线虫在NaCl存在和缺少食物条件下,对NaCl的趋向性极显著升高;与对照组相比,50.0 mg/L暴露组线虫菌落接触率在2、4、6、8 h时均显著降低,在24 h时极显著降低;各暴露组线虫的乙酰胆碱酯酶活性均受到极显著抑制. 表明久效磷能够导致线虫运动、学习与觅食行为的严重缺陷,乙酰胆碱酯酶活性抑制与久效磷对线虫运动行为的影响呈正相关,与其学习行为的影响呈负相关.      

重金属对秀丽隐杆线虫繁殖的影响

为了探究重金属单独及联合暴露对秀丽隐杆线虫(Caenorhabditis elegans)繁殖的影响及其作用机制,采用96孔板液相暴露试验,以环境相关浓度(0.1~50.0 μg/L)的Cd、Hg、Pb暴露同步化处理秀丽隐杆线虫,24 h后统计其怀卵数及阴门畸形率,以及连续记录72 h内子一代秀丽隐杆线虫的个体数,最后利用2×2析因设计方差分析阐明重金属的两两联合作用模式. 结果表明:与对照组相比,Cd、Hg、Pb单独及联合暴露对秀丽隐杆线虫的繁殖具有显著抑制作用,ρ(Cd)为50.0 μg/L、ρ(Hg)为10.0 μg/L、ρ(Pb)为50.0 μg/L暴露组秀丽隐杆线虫子一代数量分别降低了43.5%、33.8%、51.0%;Cd-Hg暴露组〔当ρ(Cd)、ρ(Hg)分别为50.0、10.0 μg/L时〕、Hg-Pb暴露组〔当ρ(Hg)、ρ(Pb)分别为10.0、50.0 μg/L时〕、Cd-Pb暴露组〔当ρ(Cd)、ρ(Pb)分别为50.0、50.0 μg/L时〕秀丽隐杆线虫子一代个体数分别降低了44.7%、61.0%、53.3%. 进一步研究发现,Cd、Hg、Pb单独及联合暴露会引起秀丽隐杆线虫子宫内受精卵数量降低以及产卵器阴门结构畸形率升高. 2×2析因设计方差分析结果发现,Cd、Hg、Pb两两联合暴露对秀丽隐杆线虫的繁殖表现为没有交互作用或者交互方式为拮抗. 研究显示,秀丽隐杆线虫子宫内怀卵数的降低是其子一代数量显著减少的主要原因,而阴门结构的损伤可能使产卵行为受损,从而进一步加剧重金属对秀丽隐杆线虫繁殖的抑制作用.      

生物炭中持久性自由基对秀丽隐杆线虫的毒性

为了评价生物炭的使用对生态系统,尤其是对土壤无脊椎动物的毒性影响,使用模式生物秀丽隐杆线虫（Caenorhabditis elegans,C.elegans）来评估生物炭的环境风险.观察了生物炭原样、生物炭颗粒物和生物炭浸提液对线虫神经行为学评价指标（身体摆动频率、相对运动长度、排泄间隔时间、碰触反应率和化学感知行为指数）的影响;并结合生物炭的理化性质、非金属元素组成和重金属元素含量以及环境持久性自由基（EPFRs）的强度,评估生物炭对线虫的生物毒性.结果显示,EPFRs信号强的生物炭和颗粒物对秀丽隐杆线虫有一定的毒物兴奋效应,EPFRs信号微弱的浸提液无显著性影响.因此,生物炭中的EPFRs对秀丽隐杆线虫有潜在的神经毒性作用.     

间甲酚对斑马鱼胚胎的影响

采用静态实验方法,研究了不同浓度的间甲酚(m-cresol)对斑马鱼胚胎的急性毒性.结果表明,当m-cresol浓度超过一定数值时,伴随着时间的延长可使暴露胚胎的畸形数增加,暴露胚胎孵化出的仔鱼也出现畸形现象,mcresol的毒性呈现出剂量-效应关系.当m-cresol质量浓度不小于13 mg/L时,暴露12 h的胚胎开始出现畸形;质量浓度为25 mg/L时,暴露24 h的胚胎全部畸形.m-cresol对胚胎24 h眼点发育及20 s主动活动、48 h黑色素和72 h各类畸形的EC50分别为33.609,8.882和5.652 mg/L.可见,一定浓度的m-cresol可对斑马鱼胚胎及其孵化仔鱼产生毒性作用.     

双酚AF暴露对胚胎期和幼鱼期斑马鱼的毒性效应

为明确不同发育阶段的斑马鱼对BPAF(双酚AF)暴露的易感性,采用暴露试验法初步研究了BPAF对胚胎期和幼鱼期斑马鱼的发育毒性. 结果表明:①BPAF暴露可延缓胚胎期斑马鱼的发育和孵化,使其出现心包水肿、卵黄囊异常、心率下降、心脏搏动停止等症状. ②暴露96 h后,ρ(BPAF)为2.0、2.5、3.0 mg/L暴露组胚胎期斑马鱼的畸形率高达100%,暴露24 h致畸的EC₅₀(半数效应浓度)为2.00 mg/L,暴露96 h的LC₅₀(半数致死浓度)为1.84 mg/L. ③暴露72 h后,对照组幼鱼期斑马鱼鱼鳔发育缺陷率为0;除ρ(BPAF)为1.0 mg/L暴露组外,其余BPAF暴露组幼鱼期斑马鱼鱼鳔发育缺陷率为100%. ④随着暴露时间的延长以及中毒程度的加深,幼鱼期斑马鱼出现的中毒症状依次表现为心包水肿、卵黄囊水肿、背脊弯曲、心跳停止,暴露48和72 h时其心包水肿的EC₅₀分别为1.76、1.56 mg/L,暴露96 h的LC₅₀为1.77 mg/L. 胚胎期和幼鱼期斑马鱼对BPAF暴露响应的差异分析显示,幼鱼期斑马鱼对BPAF暴露的反应更为敏感,幼鱼期斑马鱼的心包水肿症状可作为BPAF毒性响应的最佳指标之一.      

双酚A 对斑马鱼胚胎发育阶段的毒性及生物蓄积

为研究胚胎在不同发育阶段对外源化合物的毒性敏感差异,以0hpf、8hpf 和8h 终止3 种暴露方式进行染毒,探讨斑马鱼胚胎在不同暴露时段对双酚A(BPA)毒性和生物蓄积特征.结果表明,0hpf 暴露时,斑马鱼胚胎内BPA 含量与暴露浓度(0,5.00,10.00,15.00mg/L)及暴露时间(0,8,24,32,48,72h)呈明显正相关关系;在相同BPA 浓度(15.00mg/L)作用下,斑马鱼胚胎在0hpf 暴露下BPA 富集量比8hpf 的大,表现为致死与亚致死毒性都大,证明斑马鱼胚胎在发育早期(受精后到原肠胚期)对BPA 污染更为敏感;8h 终止试验进一步证明原肠胚期前的斑马鱼胚胎对BPA 的这种敏感特征.     

敌敌畏和丁草胺对沼蛙蝌蚪的毒性影响

采用标准水生生物毒性的测定方法研究敌敌畏和丁草胺对沼蛙蝌蚪的急性毒性效应以及对精巢发育的影响.结果表明,在水温24～ 25℃条件下,敌敌畏对沼蛙蝌蚪的24,48,72,96h半致死浓度(LC50)分别为9.104,8.064,6.304,5.680mg/L;丁草胺对沼蛙蝌蚪的24,48,72,96h半致死浓度(LC50)分别为1.400,0.860,0.795,0.735mg/L.暴露在低剂量的敌敌畏(1.42mg/L)和丁草胺(183.75×10-3mg/L)溶液中20d,沼蛙蝌蚪精巢体积分别缩小了68.14%和68.27%.污染物对蛙类生殖腺发育的影响会导致两栖动物种群的衰退.     

四溴双酚A对斑马鱼胚胎体内外发育的毒性效应

四溴双酚A(TetrabromobisphenolA,TBBPA)是广泛使用的溴阻燃剂,在环境中普遍存在.采用斑马鱼胚胎体内外微环境模拟实验,研究了TBBPA对斑马鱼(Danio rerio)胚胎体内外发育的影响.结果发现,斑马鱼胚胎直接暴露在TBBPA溶液中,会造成胚胎心包囊水肿、尾部延伸不全等畸形或使胚胎死亡;当TBBPA浓度高于1.6mg·L-1时,处理斑马鱼胚胎的致死率显著升高,与对照组有极显著差异(p<0.01),且致死效应主要发生在24h内.当TBBPA浓度为6.4mg·L-1时,斑马鱼胚胎在48h内全部死亡.在TBBPA浓度大于0.4mg·L-1的各组中,24h内斑马鱼胚胎在20s内的活动频率明显降低;当胚胎直接接触TBBPA48h,表现出的主要毒性效应为胚胎心包囊水肿,但胚胎的心率没观察到异常变化.当斑马鱼胚胎发育到72h时,TBBPA引起斑马鱼胚胎毒性的主要特征是心包囊水肿和脊柱畸形.另外,TBBPA处理后斑马鱼胚胎的孵化率和生存率均显著降低,这表明斑马鱼胚胎直接暴露在TBBPA污染的环境中,会出现明显的发育障碍,主要表现为心脏功能受损和致死效应,这些毒性特征有显著的剂量-效应关系.当成年亲代斑马鱼暴露在TBBPA溶液(1.5mg·L-1)中3～7d后,子代胚胎的发育表现出明显的毒性效应,其胚胎发育到24h和72h时的致死率均呈现一定的时间-效应关系;72h时的死亡率与对照组有极显著差异,子代胚胎的孵化率降低,但没有统计学差异;但子代胚胎的致畸率却显著升高,并呈现显著差异.研究结果表明,水体中残留的TBBPA对体内外斑马鱼胚胎的发育均有直接影响,对于鱼类的生殖和发育具有潜在的危害.     

TiO_2薄膜光催化降解邻苯二甲酸乙酯的研究

采用solgel法制备TiO2薄膜。以该薄膜为催化剂,研究了在H2O2存在的条件下,对内分泌干扰物质邻苯二甲酸乙酯(DEP)的光催化降解反应。分别讨论了pH值、H2O2的加入量、DEP的初始浓度以及光照时间对降解反应的影响。结果表明在pH=2、50mg/L的H2O2中对初始浓度为50mg/L的DEP溶液光照150min有较好的降解效果。     

用秀丽小杆线虫监测厦门岛海水水质

首次采用野生型秀丽小杆线虫( Caenorhabditis elegans )与带有HSP16启动子的转基因虫株分别对厦门岛附近5个站位的表层水样污染程度进行了监测,二者研究结果具有相关性,但采用转基因秀丽小杆线虫大大缩短了监测时间,提高了灵敏度.这是国内应用模式生物秀丽小杆线虫对环境及污染物的监测研究的首次报道.     

Optimization of the T3-induced Xenopus metamorphosis assay for detecting thyroid hormone signaling disruption of chemicals

T3-induced Xenopus metamorphosis is an ideal model for detecting thyroid hormone(TH)signaling disruption of chemicals. To optimize the T3-induced Xenopus assay and improve its sensitivity and reproducibility, we intend to develop quantitatively morphological endpoints and choose appropriate concentrations and exposure durations for T3 induction.Xenopus laevis at stage 52 were exposed to series of concentrations of T3(0.31–2.5 nmol/L)for 6 days. By comparing morphological changes induced by T3, we propose head area,mouth width, unilateral brain width/brain length, and hindlimb length/snout-vent length as quantitative parameters for characterizing T3-induced morphological changes, with body weight as a parameter for indicating integrated changes. By analyzing time-response curves, we found that following 4-day exposure, T3-induced grossly morphological changes displayed linear concentration–response curves, with moderate morphological changes resulting from 1.25 nmol/L T3 exposure. When using grossly morphological endpoints to detect TH signaling disruption, we propose 4 days as exposure duration of T3, with concentrations close to 1.25 nmol/L as induction concentrations. However, it is appropriate to examine morphological and molecular changes of the intestine on day 2 due to their early response to T3. The quantitative endpoints and T3 induction concentrations and durations we determined would improve the sensitivity and the reproducibility of the T3-induced Xenopus metamorphosis assay.     

Re-evaluation of thyroid hormone signaling antagonism of tetrabromobisphenol A for validating the T3-induced Xenopus metamorphosis assay

We developed the T3-induced Xenopus metamorphosis assay, which is supposed to be able to sensitively detect thyroid hormone(TH) signaling disruption of chemicals. The present study aimed to validate the T3-induced Xenopus metamorphosis assay by re-evaluating the TH signaling antagonism of tetrabromobisphenol A(TBBPA), a known TH signaling disruptor. According to the assay we developed, Xenopus tadpoles at stage 52 were exposed to 10–500 nmol/L TBBPA in the presence of 1 nmol/L T3. After 96 hr of exposure, TBBPA in the range of 10–500 nmol/L was found to significantly inhibit T3-induced morphological changes of Xenopus tadpoles in a concentration-dependent manner in term of body weight and four morphological endpoints including head area(HA), mouth width(MW), unilateral brain width/brain length(ULBW/BL), and hind-limb length/snout-vent length(HLL/SVL).The results show that these endpoints we developed are sensitive for characterizing the antagonistic effects of TBBPA on T3-induced metamorphosis. Following a 24-hr exposure,we found that TBBPA antagonized expression of T3-induced TH-response genes in the tail,which is consistent with previous findings in the intestine. We propose that the tail can be used as an alternative tissue to the intestine for examining molecular endpoints for evaluating TH signaling disruption. In conclusion, our results demonstrate that the T3-induced Xenopus metamorphosis assay we developed is an ideal in vivo assay for detecting TH signaling disruption.     

海水中原油对双齿围沙蚕(Perinereis aibuhitensis)的急性毒性效应及其体内抗氧化酶活性的影响

近年来海洋溢油事故频发,增加了溢油污染对海洋生物及海洋生态系统的暴露风险.为阐明海洋溢油事故对海洋生物的毒性效应,以双齿围沙蚕（Perinereis aibuhitensis）为受试生物,研究了不同质量浓度的海水原油溶液对双齿围沙蚕的急性毒性效应及抗氧化酶活性的影响.结果表明:双齿围沙蚕的死亡率与海水中原油暴露浓度呈正相关,暴露24、48及72 h的LC₅₀（半致死浓度）分别为13.08、9.80和8.37 g/L;暴露72 h后,双齿围沙蚕组织液中MDA（丙二醛）的含量均高于对照组,其中1.0 g/L暴露组显著高于对照组（P < 0.05）,且随暴露浓度的增大而升高;GST（谷胱甘肽巯基转移酶）的活性被显著诱导,且随暴露浓度的增大而升高;0.1 g/L原油暴露下,CAT（过氧化氢酶）和SOD（超氧化物歧化酶）的活性被显著诱导,当暴露浓度达到0.5 g/L时,CAT的诱导程度减弱,而SOD则受到抑制.研究显示,海水中的原油对双齿围沙蚕具有显著急性毒性效应,且0.1 g/L的原油暴露即可导致双齿围沙蚕产生脂质过氧化,脂质过氧化程度随暴露浓度的升高而增强;0.1 g/L原油暴露能显著诱导双齿围沙蚕体内抗氧化酶的活性,且随着海水中原油暴露浓度的增加,GST的诱导程度增强,CAT的诱导程度减弱,SOD的活性则受到抑制.      

Acute effects of chlorpyryphos-ethyl and secondary treated e uents on acetylcholinesterase and butyrylcholinesterase activities in Carcinus maenas

The acute effects of commercial formulation of chlorpyrifos-ethyl (Dursbanr®) and the secondary treated industrial/urban effluent (STIUE) exposure on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities in hepatopancreas and gills of Mediterranean crab Carcinus maenas were investigated. After 2 d of exposure to chlorpyriphos-ethyl, the AChE activity was inhibited in both organs at concentrations of 3.12 and 7.82 μ/L, whereas the BuChE was inhibited only at higher concentration 7.82 μ/L of commercial preparation Dursbanr®. The exposure of crabs to Dursbanr® (3.12 μ/L) showed a significant decrement of AChE activity at 24 and 48 h, whereas the BuChE was inhibited only after 24 h and no inhibition for both enzymes was observed after 72 h. Moreover, a significant repression of AChE activity was observed in both organs of C. maenas exposed to 5% of STIUE. Our experiments indicated that the measurement of AChE activity in gills and hepatopancreas of C. maenas would be useful biomarker of organophosphorous (OP) and of neurotoxic effects of STIUE in Tunisia.     

Phytoremediation potential of charophytes: Bioaccumulation and toxicity studies of cadmium, lead and zinc

The ability for usage of common freshwater charophytes,Chara aculeolata and Nitella opaca in removal of cadmium (Cd),lead (Pb) and zinc (Zn) from wastewater was examined.C.aculeolata and N.opaca were exposed to various concentrations of Cd (0.25 and 0.5 mg/L),Pb (5 and 10 mg/L) and Zn (5 and 10 mg/L) solutions under hydroponic conditions for 6 days.C.aculeolata was more tolerant of Cd and Pb than N.opaca.The relative growth rate of N.opaca was drastically reduced at high concentrations of Cd and Pb although both were tolerant of Zn.Both macroalgae showed a reduction in chloroplast,chlorophyll and carotenoid content after Cd and Pb exposure,while Zn exposure had little effects.The bioaccumulation of both Cd and Pb was higher in N.opaca (1544.3 μg/g at 0.5 mg/L Cd,21657.0 μg/g at 10 mg/L Pb) whereas higher Zn accumulation was observed in C.aculeolata (6703.5 μg/g at 10 mg/L Zn).In addition,high bioconcentration factor values (> 1000) for Cd and Pb were observed in both species.C.aculeolata showed higher percentage of Cd and Pb removal (> 95%) than N.opaca and seemed to be a better choice for Cd and Pb removal from wastewater due to its tolerance to these metals.     

蛋白核小球藻与DEP的相互作用

运用评价化学品对藻类毒性的标准实验方法,得出邻苯二甲酸二乙酯抑制蛋白核小球藻生长的９６ｈＥＣ５０为８０ｍｇ／Ｌ。实验结果表明,蛋白核小球藻对ＥＤＰ有明显的富集与降解作用,富集量和浓缩系数（ＢＣＦ）都在１２ｈ达到最大,分别为９．８ｍｇ／ｇ和２０５。此后富集量随时间的延长而逐渐降低,９６ｈ降到１．８ｍｇ／ｇ。ＢＣＦ在７２ｈ内也随时间的延长而逐渐减小,并在７２ｈ降到最小８０,７２ｈ以后又随时间的延长而升     

纳米氧化锌致大型溞的毒性效应特征

采用半静态暴露的方法,以大型溞的死亡率、显微结构损伤、蜕皮率、游泳行为等作为毒性测试终点,研究不同浓度纳米氧化锌(ZnONP)对大型溞(Daphnia magna)的毒性效应.结果显示,ZnONP水溶液稳定性差,在溶液中沉降率随着浓度增大而增大,Zeta电位降低.ZnONP对大型溞处理48 h的半数致死浓度LC_(50)为3 mg·L~(-1),ZnONP致大型溞的死亡率呈现一定的时间-效应关系;ZnONP暴露会使大型溞肠道和体表损伤.经显微结构观察发现,ZnONP可粘附在大型溞体表面,并引起大型溞游泳的垂直高度升高,大型溞蜕皮时间延迟,成功蜕皮率降低.结果表明ZnONP对大型溞个体和行为产生一定的毒性效应,其毒性效应的机理与其颗粒物对大型溞肠道和体表粘附有直接的关系,研究结果对合理地评价纳米材料对水生生物的影响有一定的理论参考价值.     

交通污染暴露对DNA甲基化的影响

探讨交通污染现场暴露对DNA甲基化的影响.30只8周龄Wistar大鼠按随机数字表法随机分5组,每组6只.其中3组分别在隧道(高暴露组)、路口(中暴露组)、校园(对照组)暴露7 d,另外2组分别在隧道暴露14 d/28 d.在暴露过程中检测3个暴露地点PM_(10)、NO_2的浓度.暴露实验分别在春季、秋季各进行一次.暴露结束后,焦磷酸测序法检测肺组织和血液中DNA(p53、MGMT、MAGE-A4)甲基化水平,并分析比较不同暴露组间DNA甲基化水平的差异.结果表明,PM_(10)、NO_2浓度均为隧道(高暴露组)路口(中暴露组)校园(对照组),差异具有统计学意义.秋季暴露7 d后,与对照组相比,肺组织中p53(P_(路口)=0.016;P_(隧道)=0.019)、MGMT(P_(路口)=0.002;P_(隧道)=0.003)启动子甲基化水平显著降低,随着暴露时间的增加,甲基化水平进一步降低;MAGE-A4启动子区处于高度甲基化状态,在肺组织和血液中,均未发现MAGE-A4启动子甲基化水平在三暴露组间存在显著的统计学差异.7d暴露对肺组织中DNA甲基化水平的影响更大,但随着暴露时间的增加,肺组织和血液中DNA甲基化水平改变模式趋于一致.Spearman相关分析结果显示,在肺组织中,PM_(10)和p53甲基化水平呈负相关关系(r=-0.347;P=0.038);NO_2和p53、MGMT、MAGE-A4甲基化水平均存在负相关(r值分别为-0.482、-0.444、-0.346,P值均0.05).在血液中,MAGE-A4甲基化水平与PM_(10)、NO_2均呈正相关(r值分别为0.395、0.431,P值均0.05).交通污染暴露会引起p53、MGMT启动子低甲基化.     

Atrazine accumulation and toxic responses in maize Zea mays

Atrazine accumulation, oxidative stress, and defense response in maize seedlings exposed to extraneous atrazine were studied. Accumulation of atrazine in maize increased with increasing exposure concentration. The abscisic acid (ABA) content was positively correlated with the atrazine concentrations in maize roots and shoots (p < 0.05). Hydroxyl radical (·OH) in maize was determined in vivo with electron paramagnetic resonance spectroscopy. Its intensity was positively correlated with atrazine concentration in roots and shoots (p < 0.05), and higher level of ·OH generated in roots than in shoots corresponded to the major accumulation of atrazine in roots. Superoxide dismutase, peroxidase and catalase in roots were up-regulated by atrazine exposure at 1 mg/L compared to the control and malondialdehyde content in roots was enhanced when atrazine exposure concentration reached 10 mg/L. These results suggested the exposure and accumulation of atrazine caused oxidative toxicity and antioxidant response in maize.