4种重金属离子对偏顶蛤的急性毒性效应

为探究偏顶蛤Modiolus modiolus对几种重金属离子的耐受能力,在水温为21²3℃、盐度为32.1、p H为8.2的试验条件下,采用静水试验法研究了Pb23℃、盐度为32.1、p H为8.2的试验条件下,采用静水试验法研究了Pb⁽²⁺⁾、Zn(2+)、Zn⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾对湿质量为(73.28±6.11)g的成体偏顶蛤的急性毒性作用。结果表明:偏顶蛤死亡率随重金属离子浓度的升高而增大,表现出明显的剂量—效应关系;4种重金属离子对试验蛤48、72、96 h的半数致死质量浓度(LC50)分别为Pb(2+)对湿质量为(73.28±6.11)g的成体偏顶蛤的急性毒性作用。结果表明:偏顶蛤死亡率随重金属离子浓度的升高而增大,表现出明显的剂量—效应关系;4种重金属离子对试验蛤48、72、96 h的半数致死质量浓度(LC50)分别为Pb⁽²⁺⁾372.392、223.357、129.122 mg/L,Zn(2+)372.392、223.357、129.122 mg/L,Zn⁽²⁺⁾292.415、113.501、62.230 mg/L,Cu(2+)292.415、113.501、62.230 mg/L,Cu⁽²⁺⁾3.373、1.189、0.506 mg/L,Cd(2+)3.373、1.189、0.506 mg/L,Cd⁽²⁺⁾106.170、47.973、24.949 mg/L;Pb(2+)106.170、47.973、24.949 mg/L;Pb⁽²⁺⁾、Zn(2+)、Zn⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾对偏顶蛤的安全浓度分别为1.291、0.622、0.005、0.250 mg/L。研究表明,单一金属对偏顶蛤的毒性大小依次为Cu(2+)对偏顶蛤的安全浓度分别为1.291、0.622、0.005、0.250 mg/L。研究表明,单一金属对偏顶蛤的毒性大小依次为Cu⁽²⁺⁾>Cd(2+)>Cd⁽²⁺⁾>Zn(2+)>Zn⁽²⁺⁾>Pb(2+)>Pb⁽²⁺⁾,其中Cu(2+),其中Cu⁽²⁺⁾对偏顶蛤属于高毒性,而偏顶蛤对Pb(2+)对偏顶蛤属于高毒性,而偏顶蛤对Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾均具有极强的耐受性。     

蛋氨酸铬对鲤糖代谢相关酶活性及IR、GLUT2和SGLT基因表达的影响

为探究蛋氨酸铬(CrMet)对鲤Cyprinus carpio糖代谢相关酶活性及糖代谢相关基因表达的影响,以酪蛋白为蛋白源,豆油为脂肪源,配制7组纯化饲料,其中Cr⁽³⁺⁾水平分别为0(对照)、0.1、0.2、0.4、0.8、1.6、3.2 mg/kg。选取初始体质量为(40.95±4.80)g的鲤,随机分为7组,分别投喂7种饲料,每个组设置3个重复,每个重复放60尾鱼,饲养8周后,检测其肝胰脏糖代谢相关酶活性;禁食48 h后再投喂,再投喂0、3、6、12、24、48 h时检测Cr(3+)水平分别为0(对照)、0.1、0.2、0.4、0.8、1.6、3.2 mg/kg。选取初始体质量为(40.95±4.80)g的鲤,随机分为7组,分别投喂7种饲料,每个组设置3个重复,每个重复放60尾鱼,饲养8周后,检测其肝胰脏糖代谢相关酶活性;禁食48 h后再投喂,再投喂0、3、6、12、24、48 h时检测Cr⁽³⁺⁾水平为0(对照)、0.8、3.2 mg/kg时鱼肝胰脏IR、GLUT2和肠道SGLT基因的表达量。结果表明:添加0.8 mg/kg Cr(3+)水平为0(对照)、0.8、3.2 mg/kg时鱼肝胰脏IR、GLUT2和肠道SGLT基因的表达量。结果表明:添加0.8 mg/kg Cr⁽³⁺⁾组的组己糖激酶(HK)、丙酮酸激酶(PK)、磷酸果糖激酶(PFK)和琥珀酸脱氢酶(SDH)活力均显著高于对照组(P<0.05),磷酸酵式丙酮酸激酶(PEPCK)活力显著低于对照组(P<0.05);而添加Cr(3+)组的组己糖激酶(HK)、丙酮酸激酶(PK)、磷酸果糖激酶(PFK)和琥珀酸脱氢酶(SDH)活力均显著高于对照组(P<0.05),磷酸酵式丙酮酸激酶(PEPCK)活力显著低于对照组(P<0.05);而添加Cr⁽³⁺⁾并未对葡萄糖-6-磷酸脱氢酶(G6PDH)活力产生显著影响(P>0.05);投喂24、48 h时,0.8 mg/kg Cr(3+)并未对葡萄糖-6-磷酸脱氢酶(G6PDH)活力产生显著影响(P>0.05);投喂24、48 h时,0.8 mg/kg Cr⁽³⁺⁾组IR mRNA表达量显著高于0、3.2mg/kg Cr(3+)组IR mRNA表达量显著高于0、3.2mg/kg Cr⁽³⁺⁾组(P<0.05);投喂3 h时,0.8、3.2 mg/kg Cr(3+)组(P<0.05);投喂3 h时,0.8、3.2 mg/kg Cr⁽³⁺⁾组GLUT2 mRNA表达量均显著高于对照组(P<0.05),12、24、48 h时,0.8 mg/kg Cr(3+)组GLUT2 mRNA表达量均显著高于对照组(P<0.05),12、24、48 h时,0.8 mg/kg Cr⁽³⁺⁾组GLUT2 mRNA表达量显著高于0、3.2 mg/kg Cr(3+)组GLUT2 mRNA表达量显著高于0、3.2 mg/kg Cr⁽³⁺⁾组(P<0.05);而不同Cr(3+)组(P<0.05);而不同Cr⁽³⁺⁾添加水平对鲤肠道SGLT mRNA表达量无显著性影响(P>0.05)。研究表明,在饲料中添加CrMet能够提高鲤对糖的利用能力,建议Cr(3+)添加水平对鲤肠道SGLT mRNA表达量无显著性影响(P>0.05)。研究表明,在饲料中添加CrMet能够提高鲤对糖的利用能力,建议Cr⁽³⁺⁾添加水平为0.8 mg/kg。     

蛋氨酸铬对鲤糖代谢相关酶活性及IR、GLUT2和SGLT基因表达的影响

为探究蛋氨酸铬(CrMet)对鲤Cyprinus carpio糖代谢相关酶活性及糖代谢相关基因表达的影响,以酪蛋白为蛋白源,豆油为脂肪源,配制7组纯化饲料,其中Cr~(3+)水平分别为0(对照)、0.1、0.2、0.4、0.8、1.6、3.2 mg/kg。选取初始体质量为(40.95±4.80)g的鲤,随机分为7组,分别投喂7种饲料,每个组设置3个重复,每个重复放60尾鱼,饲养8周后,检测其肝胰脏糖代谢相关酶活性;禁食48 h后再投喂,再投喂0、3、6、12、24、48 h时检测Cr~(3+)水平为0(对照)、0.8、3.2 mg/kg时鱼肝胰脏IR、GLUT2和肠道SGLT基因的表达量。结果表明:添加0.8 mg/kg Cr~(3+)组的组己糖激酶(HK)、丙酮酸激酶(PK)、磷酸果糖激酶(PFK)和琥珀酸脱氢酶(SDH)活力均显著高于对照组(P<0.05),磷酸酵式丙酮酸激酶(PEPCK)活力显著低于对照组(P<0.05);而添加Cr~(3+)并未对葡萄糖-6-磷酸脱氢酶(G6PDH)活力产生显著影响(P>0.05);投喂24、48 h时,0.8 mg/kg Cr~(3+)组IRmRNA表达量显著高于0、3.2mg/kg Cr~(3+)组(P<0.05);投喂3 h时,0.8、3.2 mg/kg Cr~(3+)组GLUT2 mRNA表达量均显著高于对照组(P<0.05),12、24、48 h时,0.8 mg/kg Cr~(3+)组GLUT2 mRNA表达量显著高于0、3.2 mg/kg Cr~(3+)组(P<0.05);而不同Cr~(3+)添加水平对鲤肠道SGLTmRNA表达量无显著性影响(P>0.05)。研究表明,在饲料中添加CrMet能够提高鲤对糖的利用能力,建议Cr~(3+)添加水平为0.8 mg/kg。     

苯并(a)芘对双齿围沙蚕抗氧化酶活性和细胞色素P450基因表达的影响

在实验室条件下,利用诱导试验分析了不同浓度苯并(a)芘[B(a)P]对双齿围沙蚕Perinereis aibuhitensis(体质量为1.5 g±0.5 g)细胞色素P450基因表达和肌肉组织抗氧化酶活性的影响。结果表明:双齿围沙蚕细胞色素P450基因表达与B(a)P诱导浓度和诱导时间呈正相关,随着诱导浓度的增加和暴露时间的延长,表达量逐步上调;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPx)活性均随B(a)P诱导时间的延长而逐步升高,其中SOD酶活性随B(a)P浓度的增加出现抑制,CAT和GPx酶活性则与B(a)P浓度呈正相关。     

镉对刺参幼参体内金属硫蛋白含量及其变化规律的影响

为评价水体中镉(Cd⁽²⁺⁾)对刺参Apostichopus japonicus体内金属硫蛋白(MT)的诱导效果,以刺参幼参(体质量8.87 g±1.12 g)为研究对象,在水温16(2+))对刺参Apostichopus japonicus体内金属硫蛋白(MT)的诱导效果,以刺参幼参(体质量8.87 g±1.12 g)为研究对象,在水温16¹8℃下,探讨水体中不同浓度Cd18℃下,探讨水体中不同浓度Cd⁽²⁺⁾(<0.005、0.025、0.050、0.250、0.500 mg/L)胁迫下幼参体内MT含量随Cd(2+)(<0.005、0.025、0.050、0.250、0.500 mg/L)胁迫下幼参体内MT含量随Cd⁽²⁺⁾胁迫时间(0、12、36、60、84、108h)的变化规律。结果表明:随着Cd(2+)胁迫时间(0、12、36、60、84、108h)的变化规律。结果表明:随着Cd⁽²⁺⁾胁迫时间的延长,幼参肠道、呼吸树和体壁中MT含量呈先升高后趋于平稳的趋势,且在36 h时各组织中MT含量最高或相对较高;Cd(2+)胁迫时间的延长,幼参肠道、呼吸树和体壁中MT含量呈先升高后趋于平稳的趋势,且在36 h时各组织中MT含量最高或相对较高;Cd⁽²⁺⁾胁迫36 h时,幼参体内MT含量依次为肠道>呼吸树>体壁,且Cd(2+)胁迫36 h时,幼参体内MT含量依次为肠道>呼吸树>体壁,且Cd⁽²⁺⁾胁迫后幼参各组织间MT含量有显著性差异(P<0.05);各时间点下,Cd(2+)胁迫后幼参各组织间MT含量有显著性差异(P<0.05);各时间点下,Cd⁽²⁺⁾浓度试验组幼参肠道、呼吸树和体壁中MT含量均显著高于对照组(P<0.05);在Cd(2+)浓度试验组幼参肠道、呼吸树和体壁中MT含量均显著高于对照组(P<0.05);在Cd⁽²⁺⁾胁迫各时间点,幼参肠道和呼吸树中MT含量随Cd(2+)胁迫各时间点,幼参肠道和呼吸树中MT含量随Cd⁽²⁺⁾浓度的升高呈显著"阶梯式"升高(P<0.05),体壁中MT含量则随Cd(2+)浓度的升高呈显著"阶梯式"升高(P<0.05),体壁中MT含量则随Cd⁽²⁺⁾浓度的升高而升高,Cd(2+)浓度的升高而升高,Cd⁽²⁺⁾浓度为0.025、0.050 mg/L时,体壁中MT含量相差不大(P>0.05),但均显著低于Cd(2+)浓度为0.025、0.050 mg/L时,体壁中MT含量相差不大(P>0.05),但均显著低于Cd⁽²⁺⁾浓度最高组(0.500 mg/L)(P<0.05)。研究表明,水体中的Cd(2+)浓度最高组(0.500 mg/L)(P<0.05)。研究表明,水体中的Cd⁽²⁺⁾可诱导刺参组织合成金属硫蛋白,其中对肠道和呼吸树的诱导效果最明显,36 h即可达到较为显著的诱导效果,因此,刺参肠道和呼吸树组织中的MT含量可作为评价水体中重金属Cd(2+)可诱导刺参组织合成金属硫蛋白,其中对肠道和呼吸树的诱导效果最明显,36 h即可达到较为显著的诱导效果,因此,刺参肠道和呼吸树组织中的MT含量可作为评价水体中重金属Cd⁽²⁺⁾污染的生物标志物。     

重金属铜离子酶联免疫分析方法的建立

本研究选择双功能试剂1-(4-异硫氰苄基)乙烯基二胺-N,N,N',N'-(四乙酸0TCBE),分别与载体蛋白(牛血清白蛋白,BSA;卵清蛋白,OVA)和Cu⁽²⁺⁾连接,制备出免疫原(Cu-ITCBE-BSA)和包被抗原(Cu-ITCBE-OVA),采用免疫原免疫BALB/C小鼠,利用细胞融合杂交瘤技术制备出针对Cu(2+)连接,制备出免疫原(Cu-ITCBE-BSA)和包被抗原(Cu-ITCBE-OVA),采用免疫原免疫BALB/C小鼠,利用细胞融合杂交瘤技术制备出针对Cu⁽²⁺⁾的单克隆抗体。通过优化实验条件,在Cu(2+)的单克隆抗体。通过优化实验条件,在Cu⁽²⁺⁾浓度为0(2+)浓度为0⁵00ng/mL的范围内建立了快速检测Cu500ng/mL的范围内建立了快速检测Cu⁽²⁺⁾的间接竞争酶联免疫吸附法(ELISA)方法。该方法的IC_(50)为44.09ng/mL,检出限为2.15 ng/mL。该抗体与被检测的多种金属离子均无交叉反应,特异性较强。     

宁夏二人山银铅矿床成矿流体地球化学特征及演化

宁夏卫宁北山地区二人山银铅矿是宁夏境内最典型、规模最大的银铅锌多金属矿床,矿体主要赋存于F18构造破碎带中。通过对与矿化密切共生的重晶石中的流体包裹体岩相学及显微测温分析,H2O-CO2三相包裹体均一温度为107℃～287℃,盐度变化范围为0.41%～12.05%;CO_2三相包裹体均一温度为30.2℃;富液体包裹体均一温度为95℃～248℃,盐度为2.07%～23.18%。成矿流体具有中低温、中高盐度的特征,流体为SiO_2-H_2O-CO_2-SO_4^(2-)多相含矿(Zn(2-)多相含矿(Zn⁽²⁺⁾、Pb(2+)、Pb⁽²⁺⁾、Fe(2+)、Fe⁽³⁺⁾和Ag(3+)和Ag⁺等)。     

纳米TiO_2和Cu(Ⅱ)、Zn(Ⅱ)对小球藻和新月菱形藻的毒性研究

为了研究纳米材料和重金属对水生生物的毒性作用,采用水生毒理学试验方法,考察了Ti O2纳米颗粒、重金属Cu(Ⅱ)和Zn(Ⅱ)对小球藻Chlorella sp.和新月菱形藻Nitzschia closterium的毒性。单一毒性试验结果表明,纳米Ti O2对小球藻和新月菱形藻96 h EC50分别为11.655、13.693 mg/L,Cu(Ⅱ)对小球藻和新月菱形藻的96 h EC50分别为10.197、10.033 mg/L,Zn(Ⅱ)对小球藻和新月菱形藻的96 h EC50分别为11.330、13.583 mg/L。联合毒性试验结果表明,Ti O2+Cu(Ⅱ)、Ti O2+Zn(Ⅱ)对两种微藻的联合效应EC50值均随暴露时间的延长而减小,Ti O2+Cu(Ⅱ)和Ti O2+Zn(Ⅱ)对小球藻的96 h EC50分别为9.287、11.084mg/L,对新月菱形藻的96 h EC50分别为10.632、12.954 mg/L。按照水生毒理学联合效应的相加指数法评价Ti O2+Cu(Ⅱ)、Ti O2+Zn(Ⅱ)的联合毒性效应,可知纳米Ti O2分别和Cu(Ⅱ)、Zn(Ⅱ)对小球藻和新月菱形藻的联合毒性效应均表现为拮抗作用。     

中天山狼牙泉铅锌矿床闪锌矿LA-ICP-MS微量元素特征对矿床成因的指示意义

中天山铅锌成矿带东部地块位于中亚造山带南缘,铅锌金银成矿条件优越,狼牙泉铅锌矿床是该区近年来找矿勘查所发现的重要的铅锌多金属矿床之一。本文采用激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)对该矿床闪锌矿开展了原位微区微量元素分析,分析结果表明：闪锌矿以富集Fe、Cd、Mn、Co和In而亏损Ga、Cu、Ag、Sn和Pb为特征。其中Fe、Cd、Mn、Co和In等元素以类质同象形式存在,而Cu、Pb、Sb和Ag则以类质同象和包裹体形式赋存。根据不同微量元素间的相关关系,认为闪锌矿中存在Fe²⁺(Cd²⁺/Mn²⁺)?Zn²⁺、In³⁺+Cu⁺?2Zn²⁺、Ga³⁺+In³⁺?3Zn²⁺和Sb³⁺+Ag⁺?2Zn²⁺等简单和复杂替代关系。此外,闪锌矿In/Ga比值(155.7～656.7)较高,暗示其较高的形...     

3种重金属离子对牟氏角毛藻生长的影响

采用f/2培养基,研究了不同浓度的Cu(Ⅱ)、Zn(Ⅱ)和Pb(Ⅱ))对牟氏角毛藻Chaetoceros muelleri生长的影响。结果表明:在特定浓度条件下,3种重金属离子对牟氏角毛藻的生长具有显著影响。当Cu(Ⅱ)浓度为0.1 mg/L、Zn(Ⅱ)和Pb(Ⅱ)浓度为0.1¹.0 mg/L时,能促进牟氏角毛藻的生长;Zn(Ⅱ)和Pb(Ⅱ)浓度为101.0 mg/L时,能促进牟氏角毛藻的生长;Zn(Ⅱ)和Pb(Ⅱ)浓度为10⁵0 mg/L时,牟氏角毛藻能维持一定的速率生长;Cu(Ⅱ)浓度为150 mg/L时,牟氏角毛藻能维持一定的速率生长;Cu(Ⅱ)浓度为1⁵0 mg/L时,牟氏角毛藻的生长受到显著抑制。     

天然裂缝群与地应力差作用下水力裂缝扩展试验

通过室内真三轴水力压裂试验,研究裂缝性储层中天然裂缝群与地应力差的组合作用对水力裂缝扩展的影响。采用内含大量随机天然裂缝的300 mm×300 mm×600 mm人工试件模拟裂缝性储层,改变地应力差、天然裂缝尺度以及压裂液排量与黏度条件,分析水力裂缝形态与地应力差、天然裂缝尺度的关系。根据水力裂缝复杂程度将其分为体积裂缝、分支裂缝和单一裂缝3类。结果表明:天然裂缝尺度越大、地应力差越小,水力裂缝形态越复杂;对含天然裂缝群的储层,当地应力差大于8 MPa时,压裂不会产生体积裂缝;当地应力差大于14 MPa时,天然裂缝群对水力裂缝形态不会产生影响,形成单一裂缝;水力裂缝的非稳态扩展易受到天然裂缝群的影响,从而有利于产生缝网结构。     

高效抗紫外太阳电池封装用EVA胶膜的研制

有机高分子改性的高效抗紫外EVA胶膜的制造新技术,与现有技术相比,在传统太阳能电池封装用EVA胶膜配方中引入铕(Eu)元素,利用Eu对短波长高能量紫外光的吸收转换作用,将紫外光部分转换成可见光,以提高太阳电池组件对光的利用率,目前在光伏领域的应用研究尚属首次。     

半定量和定量分析测定SBS颗粒抗氧剂含量

运用气相色谱/质谱,以2,6二叔丁基对甲酚的相对峰面积为分析参数,对某仓库火灾涉及的SBS弹性体颗粒中影响火灾危险性的抗氧剂进行半定量和定量分析。通过半定量分析筛查不同位置和不同批次的多个SBS颗粒抗氧剂,找出抗氧剂含量异常的样品,在此基础上进行定量分析。实验结果表明,通过半定量方法筛选出抗氧剂含量异常的2号样品,经定量分析测定其抗氧剂含量仅为0.011%,远远低于正常值0.25%,由此为消防部门认定此起火灾的性质提供了依据。     

Radiation dose and antioxidant depletion in a HDPE geomembrane

The impact of α and β radiation on antioxidant depletion in smooth high-density polyethylene (HDPE) geomembranes (GMs) is described. Smooth HDPE GMs having different thickness (0.04-mm, 0.1-mm, 0.2-mm) were created by mechanically pulverizing sections of 2-mm-thick smooth HDPE GM and extruding the polymer at different thicknesses using a film blowing machine. The 2-mm-thick smooth HDPE GM was also used in the experiments. HDPE GM specimens were exposed to sealed sources of ²⁴¹Am and ⁹⁹Tc for 1–50?h to simulate the impact of α and β radiation from U and ⁹⁹Tc in low-level radioactive waste (LLW) leachate. Standard oxidative induction time (OIT) tests were conducted to determine antioxidant depletion. No change in OIT occurred in the 2-mm-thick HDPE GM after exposure to sealed sources of ²⁴¹Am and ⁹⁹Tc for 50?h. In much thinner GMs (e.g., 0.04?mm), however, significant antioxidant depletion occurred after exposure most likely due to penetration of α and β particles. Penetration depth of α and β particles and dose deposition in HDPE GMs were estimated with the GEometry ANd Tracking (GEANT4) program. Predictions from GEANT4 show that maximum dose deposition occurs at the surface of the HDPE GM and decreases with depth. A multilayer model is used to estimate antioxidant depletion in HDPE GMs for depth-dependent doses. These estimates suggest that radiation from LLW leachate has an insignificant effect on antioxidant depletion in HDPE GMs due to the low dose deposition (e.g., 2.42?Gy) expected over a 1000-yr service life, even if the level of activity in LLW leachate increases 10x to 100x the level typical of today.     

不同季节早园竹叶提取物抗氧化能力研究

以徐州地区早园竹叶为研究对象,采用Fenton反应和CuSO4-Phen-Vc-H2O2-DNA反应法测定竹叶提取物的抗氧化活性,以考察竹叶提取物抗氧化活性随季节的变化规律。结果表明:随着竹叶提取物浓度的增加,对自由基的抑制能力增强。但是不同季节原料中含有的提取物抑制自由基效果有一定的差距,抗氧化能力依次为夏季>秋季>冬季>春季。     

Effect of high temperatures on antioxidant depletion from different HDPE geomembranes

The effect of elevated temperatures, typically 95–115 °C, on antioxidant depletion from a high-density polyethylene (HDPE) geomembrane (GMB) incubated in air, water and synthetic leachate is examined. It is shown that the antioxidant depletion in synthetic leachate at 95–115 °C is consistent with what would be expected from Arrhenius modeling based on data from lower temperatures (25–85 °C). A similar finding is reached for incubation in air. However, when incubated in water the antioxidant depletion is more complicated. At temperatures above 100 °C a four-parameter exponential model was needed to fit oxidative induction time data that exhibited quite different early-time and later-time depletion rates. The early-time depletion rate decreases with an increase of the temperature while the later-time depletion rates follow the more typical pattern of increasing with increasing temperature. Three additional HDPE GMBs with different antioxidant packages are examined at elevated temperatures in air. The GMB with the lowest initial standard (Std) oxidative induction time (OIT) and without hindered amine light stabilizer (HALS) has the longest antioxidant depletion stage based on Std-OIT at these elevated temperatures. GMBs stabilized with HALS showed only a slight change in their high pressure OIT during the current study. It is shown also that degradation in physical properties can start at Std-OIT values above the residual OIT values.     

Detection of water soluble lectin and antioxidant component from Moringa oleifera seeds

Seed flour from Moringa oleifera is widely used as a natural coagulant for water treatment in developing countries. Extracts obtained by water soaking of M. oleifera intact seeds were investigated for the presence of lectin, trypsin inhibitor, tannin as well as antioxidant activity. A water soluble M. oleifera lectin (WSMoL) detected was mainly active with rabbit cells at pH 4.5; heat treatment, pH 7.0, fructose and porcine thyroglobulin abolished HA of WSMoL. Trypsin inhibitor or tannins were not detected; the antioxidant component (WSMoAC) reduced 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) was slower than catechin and was thermostable. The extracts showed a primary glycopolypeptide band of Mw 20,000; the main native acidic protein showed hemagglutinating activity. WSMoL may be involved in seed coagulant properties.     

复合酶法提取蕨麻多糖及其抗氧化活性研究

确定了复合酶(纤维素酶、果胶酶、中性蛋白酶)提取蕨麻多糖的最佳工艺,并对其体外抗氧化活性进行初步研究.在单因素试验的基础上,设计L9(33)正交实验和L9(34)正交实验,分别得出复合酶的最佳配比和复合酶法提取蕨麻多糖的最佳提取工艺条件;采用清除·OH(羟基)自由基模型和O2一·(超氧阴离子)自由基模型评价了蕨麻多糖的抗氧化能力.结果表明:复合酶的最佳配比为:纤维素酶2.0%,木瓜蛋白酶1.0%,果胶酶2.0%;最佳工艺条件为:料液比为1:30、p H值为4.5,温度为45℃,酶解时间为60min,此时蕨麻多糖的提取率最大为8.12%,同时验证性实验也表明优化得到的提取工艺稳定可靠;蕨麻多糖对羟基自由基和超氧阴离子都具有较强的清除作用,并与浓度呈一定依赖关系,且对羟自由基的清除能力要比超氧阴离子自由基的清除能力强.     

Fate and effect of the antioxidant ethoxyquin on a mixed methanogenic culture

The potential inhibitory effect of ethoxyquin, an antioxidant commonly used as a preservative in the food processing industry (e.g., for stabilizing dissolved air flotation residuals), was evaluated at concentrations up to 300 mg/L using a mixed, mesophilic (35 degrees C) methanogenic culture and dextrin, peptone and methanol as the carbon source. A batch assay conducted with a range of ethoxyquin concentrations did not result in any inhibition up to an ethoxyquin concentration of 75 mg/L, but severe inhibition of methanogenesis was observed at concentrations higher than 150 mg/L. Ethoxyquin addition to a batch reactor with the same mixed, methanogenic culture, at ethoxyquin concentrations gradually increasing over 100 days, resulted in a transient and a complete inhibition of methanogenesis at ethoxyquin concentrations of 150 and 300 mg/L, respectively. Acidogens were not significantly impacted, whereas aceticlastic and methanol degrading methylotrophic methanogens were impacted the most. Acclimation of the methanogenic culture to ethoxyquin was not observed over an incubation period of more than 100 days. Long-term (>100 days) incubation at sub-inhibitory ethoxyquin concentrations did not result in ethoxyquin biotransformation. Similarly, ethoxyquin biotransformation was not evident over an 8-day aeration period in a laboratory-scale activated sludge reactor operated under fully aerobic conditions. Ethoxyquin phase distribution tests conducted with the mixed, methanogenic culture at 1.61 g/L volatile solids concentration and nominal ethoxyquin concentrations equal to or higher than 300 mg/L resulted in solid phase/liquid phase ethoxyquin ratios equal to or higher than 1.0. The combined effect of ethoxyquin recalcitrance under anaerobic conditions along with its phase distribution, which favors biosolids, will result in ethoxyquin accumulation in anaerobic treatment systems used by the food processing industry. Such accumulation may pose concerns relative to inhibitory effects in these treatment systems and the disposal of ethoxyquin-bearing biosolids.     

Ecotoxicological effects of the antioxidant additive propyl gallate in five aquatic systems

Propyl gallate is an antioxidant widely used in foods, cosmetics and pharmaceuticals. The occurrence and fate of additives in the aquatic environment is an emerging issue in environmental chemistry. To date, there is little available information about the adverse effects of propyl gallate on aquatic organisms. Therefore, the toxic effects were investigated, using five model systems from four trophic levels. The most sensitive system was the hepatoma fish cell line PLHC-1 according to total protein content, with an EC(50) of 10 microM and a NOAEL of 1 microM at 72 h, followed by the immobilization of Daphnia magna, the inhibition of bioluminescence of Vibrio fischeri, the salmonid fish cell line RTG-2 and the inhibition of the growth of Chlorella vulgaris. Although protein content, neutral red uptake, methylthiazol metabolization and acetylcholinesterase activity were reduced in PLHC-1 cells, stimulations were observed for lysosomal function, succinate dehydrogenase, glucose-6-phosphate dehydrogenase and ethoxyresorufin-O-deethylase activities. No changes were observed in metallothionein levels. The main morphological observations were the loss of cells and the induction of cell death mainly by necrosis but also by apoptosis. The protective and toxic effects of propyl gallate were evaluated. General antioxidants and calcium chelators did not modify the toxicity of propyl gallate, but an iron-dependent lipid peroxidation inhibitor gave 22% protection. The results also suggest that propyl gallate cytotoxicity is dependent on glutathione levels, which were modulated by malic acid diethyl ester and 2-oxothiazolidine-4-carboxylic acid. According to the results, propyl gallate should be classified as toxic to aquatic organisms.