全氟辛烷磺酰基化合物对剑尾鱼肝脏抗氧化物酶活性的影响

目的研究全氟辛烷磺酰基化合物(PFOS)暴露对剑尾鱼(Xiphophorus helleri Heckel)抗氧化物酶活性的影响,探讨PFOS对鱼类的致毒机理。方法使用浸润法以3.5、7.0、14.0和28.0 mg/L四个PFOS浓度为剑尾鱼染毒,定量测定了96 h内肝脏组织中的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)活性及丙二醛(MDA)含量的变化。结果 PFOS暴露12 h后,除28.0 mg/L组SOD活性被显著性抑制外,其余各组与对照组均无显著性差异(P>0.05);7.0 mg/L组和14.0 mg/L组在24 h被极显著诱导(P<0.01),并且一直保持至96 h。CAT活性随PFOS浓度的升高而降低,12 h时,除3.5 mg/L组外,其余各组CAT活性被显著或极显著抑制,至24 h时,各组CAT活性有上升趋势,但48 h后,各组呈不断下降趋势持续至96 h,其CAT活性恢复到12 h水平。GSH-PX活性变化与CAT活性变化趋势相似,其中28.0 mg/L组在不同时间均被显著性抑制,并在96 h时抑制率达到最高值64.8%。MDA含量在12 h时呈小幅下降趋势,但随着暴露时间的延长,各处理组MDA含量呈连续上升趋势,并在96 h时达到最高点,诱导率分别为71.2%、70.1%和85.1%。结论结果表明,SOD的高活性是由于机体中超氧阴离子的存在,而高浓度的超氧阴离子能够灭活CAT和GSH-PX活性,因此,CAT和GSH-PX活性始终低于对照组。GSH-PX对PFOS的敏感性高于CAT。MDA含量持续升高反映出细胞组织已经遭受到氧化损伤。剑尾鱼活体的实验表明,PFOS能够诱导肝脏氧化应激反应,氧化损伤是PFOS致毒的主要途径之一。     

17α-甲基睾酮对剑尾鱼的影响

目的研究17α-甲基睾酮暴露对产后雌性剑尾鱼(Xiphophorus helleri)性逆转组织形态学变化的影响,探讨剑尾鱼第二性征变化作为水环境风险评价(ERA)的有效生物学标记的可能性。方法使用浸浴法以10μg/L 17α-甲基睾酮为剑尾鱼染毒持续7周,对实验鱼的体形、腹鳍、臀鳍、尾鳍及性腺等组织器官的变化进行观察;同时对幼鱼在实验室养殖条件下的性别分化进行统计。结果 17α-甲基睾酮对产后雌鱼有明显的影响,受诱导后出现性逆转,逐渐发育形成雄性第二性征:体形变纤细;腹鳍第1鳍条变短、第2和第3鳍条延长,臀鳍第3、4、5鳍条末端钩状化且第3鳍条变粗壮,尾鳍上下缘出现增生;体内与臀鳍相连的骨骼合并生长;受诱导的雌鱼性腺呈现退化趋势并伴有卵细胞坏死现象,生殖能力受到负面影响。结论剑尾鱼臀鳍和尾鳍变化可作为水环境雄激素物质污染监测的有效生物学标记。     

不同粒径微塑料对剑尾鱼肠道消化、抗氧化及免疫酶活性影响

研究表明,微塑料对生物体具有不利影响。本研究以剑尾鱼Xiphophorus helleri为实验对象,将其暴露于不同粒径（0、1μm、5μm、1μm与5μm按颗粒数1∶1混合粒径）、不同浓度（0、1×10⁶粒/L、1×10⁷粒/L）聚苯乙烯微塑料水环境72 h后,测定其消化酶、抗氧化酶及免疫酶活性。与对照组相比,各暴露组肠道淀粉酶、脂肪酶和胰蛋白酶活性均显著升高（P<0.05）,超氧化物歧化酶和谷胱甘肽过氧化物酶活性显著下降（P<0.05）,过氧化氢酶活性显著升高（P<0.05）,丙二醛和溶菌酶活性显著升高（P<0.05）。微塑料急性暴露会干扰剑尾鱼对食物的消化吸收,并影响其肠道抗氧化酶和免疫酶的活性。     

近交系剑尾鱼的STR遗传检测技术

目的建立近交系实验用鱼DNA检测方法,用于遗传质量控制。方法以RR-B、RW-H、BY-F三个近交系剑尾鱼的基因组DNA为主要研究对象,并以非选育剑尾鱼作对照,采用STR（short tandem repeat）引物扩增方法检测不同品系在DNA上的异同。设计10对STR引物,优化PCR电泳条件,使用相同的实验条件进行重复,以得到可靠的扩增条带,筛选出特异性引物。结果有4对引物可扩增出稳定条带,1对引物（AY204223）的PCR扩增条带在非选育群中表现多态性,在RR-B与BY-F系表型一致,与RW-H表型不同。这些STR位点能够区分剑尾鱼三个近交系品系。结论STR检测技术可望用于近交系剑尾鱼的遗传质量监测。     

鳗弧菌侵染对青蛤溶菌酶和超氧化物岐化酶活性的影响

青蛤样品分别注射鳗弧菌和生理盐水,在注射后3 h、6 h、12 h、24 h、36 h和48 h取不同处理组血清,测定其溶菌酶(LSZ)和超氧化物歧化酶(SOD)活性,分析鳗弧菌对青蛤体内免疫相关酶活性的影响.结果表明,鳗弧菌感染组的青蛤血液中LSZ和SOD活性均有显著升高的趋势,SOD在12 h时达到最高,LSZ在36 h达到最高,均与对照组差异显著(P<0.05),随后呈现下降趋势.表明鳗弧菌对青蛤的LSZ与SOD酶活性影响较大,对其免疫防御系统有明显的刺激作用.     

剑尾鱼杂交种黑色素瘤的形成和病理观察

目的通过剑尾鱼属内鱼类的杂交,观察黑色素瘤在其杂交后代的形成情况。方法白体剑尾鱼(♀)与黑体剑尾鱼(♂)杂交,子一代(F1)和子二代(F2)分别自交,观察其后代外部特征变化和黑色素瘤形成的情况;对黑色素瘤进行组织病理观察。结果剑尾鱼杂交种的F2代开始出现性状分离,F3中有较高的黑色素瘤发生率,为20.5%。HE染色和Lillie黑色素染色证实增生组织为黑色素瘤。结论通过不同剑尾鱼的杂交和自交,后代有黑色素瘤形成,可望进行黑色素瘤模型的构建。     

剑尾鱼近交系遗传纯度的RAPD分析

目的　分析近交系剑尾鱼 (Xiphophorushelleri)的遗传纯度 ,以指导剑尾鱼实验动物化的培育工作。方法　应用经过筛选的 2 9条随机引物对剑尾鱼的第 19代近交系 12尾剑尾鱼个体基因组DNA进行RAPD扩增 ,计算近交系个体间的相似系数及遗传距离。结果　筛选的 2 9条引物共扩增出 30 6条带 ,扩增片段的大小在 0 2 - 3kb之间。其中多态性带 2 9条 ,多态性带频率在 0～ 5 0 0 0 %之间 ,平均为 9 48%。近交系剑尾鱼不同个体拥有相同条带的比率较高。计算得到近交系的平均相似系数 (S)为 0 9839(0 973～ 0 997) ,平均等位基因频率 ( q)为 0 8731,最低平均杂合率 ( H)为 0 12 6 9。 结论　剑尾鱼第 19代近交系有较高的遗传纯合度。     

17β-雌二醇对雄性剑尾鱼生长发育的影响

用组织学的方法研究了50μg/L 17β-雌二醇(E2)持续50d暴露对剑尾鱼精巢、肝脏和鳃组织结构变化的影响,结果显示,剑尾鱼受E2暴露后,精巢内的精小囊数量减少,精原细胞发育停滞,精子数量稀少甚至没有;肝细胞胞质内出现脂肪空泡和脂肪沉积等脂肪肝症状;鳃丝和鳃小片出现不同程度的肿胀、增生、融合现象.结果表明,E2具强雌激素效应.对剑尾鱼精巢、肝脏和鳃组织的损伤具有时间效应,随着暴露时间延长其损伤更严重,但都在其耐受范围之内,未造成鱼体的死亡.精巢组织结构损伤可作为检测水环境雌激素污染生物标记.     

17β-雌二醇对雄性剑尾鱼精巢和肝发育的影响

用组织学的方法研究了50μg/L 17β-雌二醇(E2)持续50 d暴露对剑尾鱼(Xiphophorus helleri)精巢和肝组织结构变化的影响.结果显示,剑尾鱼受E2暴露后,精巢内的精小囊数量减少,精原细胞发育停滞,精子数量稀少甚至没有;肝细胞胞质内出现脂肪空泡和脂肪沉积等脂肪肝症状.结果表明,E2具强雌激素效应,对剑尾鱼精巢和肝组织的损伤具有时间效应,随着暴露时间延长其损伤更严重,但都在其耐受范围之内,未造成鱼体的死亡.精巢组织结构损伤可作为检测水环境雌激素污染生物标记.     

利用微卫星多重PCR技术鉴定剑尾鱼RR-B系

目的建立多重PCR技术鉴定选育剑尾鱼RR-B系的方法。方法根据可明显鉴定剑尾鱼RR-B系的6对特异性微卫星引物Msa012、Msa014、Msa033、Msb025、Msd003、Msd051,采用不同的组合方式对RR-B系剑尾鱼和红眼红体的非选育剑尾鱼进行多重PCR扩增。结果引物组合1(Msa014、Msb025、Msd003)和组合2(Msa012、Msa033、Msd051)两个三重PCR反应体系能清楚的扩增各个微卫星座位,且各目的片段之间无干扰,易于识别,引物组合1的排除概率为99.98%,引物组合2的排除概率为99.96%,能准确鉴定剑尾鱼RR-B系。结论本检测方法具有较高的稳定性,可快速准确鉴定剑尾鱼RR-B系。     

剑尾鱼线粒体细胞色素b基因的序列分析

目的　克隆和测定剑尾鱼 (Xiphophorushelleri)线粒体细胞色素b基因 (cytb)的全序列。方法　提取剑尾鱼肝脏的总DNA。设计合成特异引物进行PCR扩增。扩增产物经琼脂糖电泳检测、纯化后克隆到pGEM Teasyvectorsystem中的T载体上 ,筛选转化子 ,提取质粒 ,酶切鉴定。挑取重组质粒pGEM T xhcytb 11进行序列测定。结果　获得了剑尾鱼线粒体cytb基因的全序列 ,共 114 0bp。结论　用BLAST与GenBank中的线粒体DNA序列进行比较 ,显示剑尾鱼与其他鱼类的cytb基因具有较高的同源性 ;根据剑尾鱼与其他 13种鱼的cytb基因序列同源性所建立的进化树 ,与传统的分类地位基本吻合     

17β-雌二醇对剑尾鱼卵黄蛋白原的诱导研究

目的研究17β-雌二醇(E2)暴露对雄性剑尾鱼(Xiphophorus helleri)卵黄蛋白原(vitellogenin,Vtg)诱导作用作为环境风险评价(ERA)的有效生物学标记的可行性。方法以E2诱导的剑尾鱼雄性个体的整体匀浆液为材料,采用Sephacryl S-300凝胶过滤层析柱和QSepharose阴离子交换柱从剑尾鱼体内提纯Vtg。结果确定了被纯化的剑尾鱼Vtg在4%~7.5%Native PAGE电泳中相对分子质量为540×103。4%~7.5%Native PAGE电泳后的凝胶分别利用苏丹黑B进行脂蛋白染色、高碘酸-Schiff试剂进行糖蛋白染色和甲基绿进行磷蛋白染色,表明剑尾鱼Vtg是一种富含糖、脂、磷的蛋白。结论表明雄性剑尾鱼卵黄蛋白原的诱导变化可作为环境风险评价(ERA)的有效生物学标记。     

近交系剑尾鱼的遗传生化标记研究

目的通过研究对RR-B、RW-H、BY-F三个近交系和非选育剑尾鱼的研究比较,建立近交系剑尾鱼的遗传生化标记检测技术。方法依照国标GB／T14927.1-2008的遗传操作规程优化实验条件,对三个近交品系及非选育群剑尾鱼的不同组织的6个遗传生化位点进行研究,以得到其遗传生化图谱。结果在6个生化位点中,同一品系剑尾鱼同工酶存在组织特异性,多数同工酶在肝中活性较强。同一生化位点在不同品系间存在差异。RR-B系在葡萄糖磷酸异构酶（Gpi）、6-磷酸葡萄糖脱氢酶（Gpd）位点表现出特异性条带,RW-H系在过氧化氢酶（Ce）位点表现出特异性条带。同一生化位点在各品系内表现较为一致,而在非选育剑尾鱼中在上述三个生化位点表现出多态性。在酯酶（ES）、碱性磷酸酶（AKP）、乳酸脱氢酶（LDH）位点,各品系谱带不易区分其差异。结论建立了剑尾鱼近交系生化标记检测技术,可望用于近交系剑尾鱼的遗传质量监测。     

Determination of Manganese Superoxide Dismutase Activity By Direct Spectrophotometry

A method to determine Mn-superoxide dismutase activity by measuring directly the rate of decay of O₂^- in a spectrophotometer, is described. Decay of O₂^- generated by KO₂ at pH 9.5, was monitored as the fall in absorbance (A_250nm-A_360nm). Mn-superoxide dismutase was determined as the activity of cyanide-resistant superoxide dismutase, calculated from the rate of O₂^- dismutation. Mn-superoxide dismutase could be determined in the presence of a 700 times higher Cu, Zn-superoxide dismutase activity. The alkaline pH did not cause analytical problems. The assay was used to measure both Mn- and Cu, Zn-superoxide dismutase activity in mitochondrial preparations. The assay had a detection limit of 2.8 ng/ml when Mn-superoxide dismutase from E. coli was used, and the between-day CV was 5.8%. The assay is an alternative to indirect methods for detecting superoxide dismutase activity.     

Temporal Variation in Hepatic Superoxide Dismutase Activity in Mice

Circadian variations in superoxide dismutase (SOD) activity were determined in liver homogenates of Balb-C mice that were synchronized under controlled environmental conditions with 12 h light: 12 h dark. The activity of hepatic SOD exhibited a significant circadian rhythm, with a minimum at 01:00 h and maximum at 10:00-13:00 h. It is concluded that fluctuations in hepatic SOD activity render mice more susceptible to the toxic effects of reactive oxygen radicals at particular times of the day.     

Histochemical Localization of Superoxide Dismutase Activity in Rat Brain

Histochemical localization of superoxide anion (O₂^·−) scavenging activity in rat brain was visualized by the tissue-blotting technique. The activity was thought to mainly depend on Cu/Zn-SOD, because the localization of the activity was identical with the immunohistochemistry of Cu/Zn-SOD and the localization of its mRNA in the brain. Moreover, the activity was dramatically decreased after treatment of Cu (I) chelater. The activity was detected in pyramidal cells of the cortex, granular, and mitral cells of the olfactory bulbs, pyramidal cell layer CA1 to CA3, and dentate gyrus of hippocampus formation and granular cells of the cerebellum. Moreover, the activity was detected in the pontine nuclei of brain stem. Olfactory bulbs, hippocampus, and cerebellum were believed to be bestowed high brain functions, i.e., long-term potentiation and long-term depression. A part of the function was regulated by a retrograde neurotransmitter, nitric oxide (^·NO). Our findings suggest that the SOD is colocalized with NO synthase in olfactory bulbs, hippocampus, and cerebellum, where ^·NO plays the important roles. In contrast, low SOD activity was observed in the axonal neurofiber bundles, although the regions contain a lot of membrane lipids, which was thought to be peroxidized by O₂^·− and related radicals such as ^·OH in the regions. From these findings, it was suggested that the SOD did not only play a role in protecting the neurons from endogenously formed O₂^·−, but also play a role in preservation of beneficial natures of ^·NO in the brain.     

Changes in Superoxide Dismutase Activity in Liver and Lung of Old Rats

Superoxide dismutase activity was measured in liver and lung from 3 and 24 month-old rats. Both total SOD and Mn-SOD activity decreased significantly in the liver of old rats. Recent results from our laboratory have indicated that during aging, the activity of Cu/Zn-SOD decreases in rat liver and that there is an accumulation of altered protein. It was also shown that the old Cu/Zn-SOD had one histidine fewer than the young one. In the present study, the immunoprecipitation experiments showed that the amount of immunoprecipitable Mn-SOD from liver of old rats was greater than from young ones, but when amino acid residues were measured in purified young and old Mn-SOD from liver, no change was observed. In lung, no significant age-related differences in total SOD, Cu/Zn-SOD and Mn-SOD activity were found, nor was there accumulation of altered protein during aging.     

Effects of Ce<Superscript>3+</Superscript> on Conformation and Activity of Superoxide Dismutase

Ce³⁺ in various concentrations was added to superoxide dismutase (SOD) from rat eryhrocyte in vitro to gain insight into the mechanism of molecular interactions between Ce³⁺ and SOD. The results showed that the reaction between SOD and Ce³ was two order, which meant that the SOD activity was markedly accelerated by a low concentration of Ce³⁺ and inhibited by a high concentration of Ce³⁺. The spectroscopic assays suggested that the Ce³⁺ was determined to directly bind to SOD; the binding site of Ce³⁺ to SOD was 0.96, and the binding constants (K _A) were 6.78 × 10⁵ and 1.68 × 10⁵L·mol⁻¹; the binding Ce³⁺ entirely altered the secondary structure of SOD. It implied that the Ce³⁺ coordination created a new metal ion-active site form in SOD, thus leading to an enhancement in SOD activity.