羧基化多壁碳纳米管对蛋白核小球藻的生物学效应研究

碳纳米材料由于其具有优异的性能,得以广泛生产和使用,因而不可避免地进入水环境中,对水生生态系统造成潜在的影响。羧基化多壁碳纳米管(MWCNTs-COOH)作为功能化多壁碳纳米管的一种,其应用亦非常广泛,其潜在的环境效应受到人们越来越多的关注。以蛋白核小球藻(Chlorella pyrenoidosa)作为受试生物,通过暴露实验研究了MWCNTs-COOH对蛋白核小球藻的生物学效应。研究结果表明:1)MWCNTs-COOH在中高浓度以下(≤20 mg·L~(-1))未对C.pyrenoidosa生长造成影响;2)暴露96 h后,中、高浓度(10、20 mg·L~(-1))促进C.pyrenoidosa细胞可溶性蛋白的合成,但在高浓度(≥40 mg·L~(-1)),MWCNTsCOOH对C.pyrenoidosa造成毒性效应;3)随着MWCNTs-COOH浓度的增加,C.pyrenoidosa细胞总抗氧化能力(T-AOC)值减少,C.pyrenoidosa细胞丙二醛(MDA)含量显著增加,细胞的健康程度逐渐恶化,细胞结构受到严重损伤。     

多壁碳纳米管对小鼠肺脏和肝脏组织SOD活力和GSH含量的影响

为了研究多壁碳纳米管(MWCNTs)对小鼠肺脏和肝脏组织抗氧化系统的影响,将20只雄性昆明小鼠随机分成4组,采用腹腔注射进行一次性染毒,其中3个染毒组分别腹腔注入0.1、0.2、0.4mg·mL-1的多壁碳纳米管(粒径20～40nm)悬液1mL,对照组注入等体积生理盐水,染毒5d后测定肺脏和肝脏组织匀浆中超氧化物歧化酶(SOD)活力、还原型谷胱甘肽(GSH)含量.结果表明,随着多壁碳纳米管染毒浓度的升高,小鼠肺脏和肝脏组织SOD活力、GSH含量均呈逐渐降低趋势;在实验浓度(0～0.4mg·mL-1)下,SOD活力、GSH含量与多壁碳纳米管染毒浓度呈明显的剂量-效应关系.以上结果表明多壁碳纳米管对小鼠肺脏和肝脏抗氧化系统具有一定程度的抑制作用。     

羧基化多壁碳纳米管与铅镉对蚕豆幼苗叶片的氧化损伤

蚕豆幼苗悬浮培养于含有羧基化多壁碳纳米管MWCNTs-COOH(0、2.5、5.0和10.0 mg·L~(-1))、20.0μmol·L~(-1)Pb+5.0μmol·L~(-1)Cd(简称Pb+Cd),以及MWCNTs-COOH与Pb+Cd的复合溶液中,15 d后检测叶片生理生化指标的变化,以期为MWCNTs与Pb、Cd复合污染的植物毒性和生态风险性评价提供科学依据。结果表明,随着MWCNTs-COOH浓度的增加,与对照组比较,MWCNTs-COOH单一或与Pb+Cd的复合溶液均诱导了叶片O_2~(·-)和H_2O_2产物的明显积累,并伴随着超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)及愈创木酚过氧化物酶(POD)同工酶及其酶活性的升高。2.5 mg·L~(-1)MWCNTs-COOH单一或与Pb+Cd的复合显著诱导CAT酶活性,10.0 mg·L~(-1)MWCNTs-COOH与Pb+Cd的复合导致CAT酶活性降低至对照组以下,CAT酶可作为早期诊断MWCNTs-COOH或MWCNTs-COOH复合重金属环境污染的敏感的生物标志物。MWCNTsCOOH还诱导了蛋白羰基化、热休克蛋白70(HSP70)、非蛋白巯基(NPT)产物和内肽酶(EP)同工酶活性的增加,与Pb+Cd复合后HSP70产物趋于降低,而蛋白羰基化和NPT产物以及EP酶活性显著升高。叶片抗氧化酶和EP酶活性的升高、HSP70和NPT产物的增加缓解了上述氧化胁迫与损伤,是蚕豆幼苗重要的防御机制。综上,MWCNTs-COOH诱导了蚕豆叶片的氧化胁迫和应激响应,与Pb+Cd复合后则加剧了叶片的氧化损伤与蛋白降解。     

水体系中官能化多壁碳纳米管光致活性氧研究

采用间歇超声法制得水体稳定分散的羟基化多壁碳纳米管(MWNT-OH)和羧基化多壁碳纳米管(MWNT-COOH)悬浮液,并考察了它们在氙灯光照下产生活性氧(ROS)的能力.分别以呋喃醇和对氯苯甲酸为鉴定单重态氧(1O2)和羟基自由基(.OH)的分子探针,测得浓度为mgC.L-1级的碳纳米管悬浮液在模拟阳光辐射下生成1O2和.OH的稳态浓度分别可达10-14mol.L-1和10-15mol.L-1.MWNT-OH和MWNT-COOH生成1O2能力接近,但MWNT-OH光致产生.OH能力高于MWNT-COOH.增加碳纳米管浓度(0.8—8 mgC.L-1)可以提高光致活性氧的稳态浓度.     

羧基化碳纳米管修饰电极伏安法测定湘江水样中间苯三酚

基于羧基化多壁碳纳米管(c-MWCNT)修饰玻碳电极,建立了无汞、高灵敏度测定痕量间苯三酚的新方法.利用循环伏安(CV)法、交流阻抗法(AC)对该修饰电极进行了表征;用线性扫描伏安法(LSV)研究了间苯三酚在修饰电极上的电化学行为.实验结果表明,在0.1 mol·L-1的磷酸缓冲液(pH 6.8)中,当间苯三酚在c-M...     

气态甲醛致雌性小鼠生殖细胞DNA-蛋白质交联的研究

为了研究气态甲醛对雌性小鼠生殖细胞的影响,以昆明雌性小鼠卵巢为实验材料,采取动态吸入式染毒方式,应用KCl-SDS沉淀法检测了气态甲醛染毒后所引起的小鼠卵巢生殖细胞DNA-蛋白质交联(DPC)效应.结果表明,较低浓度的甲醛(0.5mg·m-3),即可导致明显的DPC效应(与对照相比,p<0.05),并且随着染毒浓度的升高(0.5、1.0、3.0mg·m-3),DPC系数也逐渐升高.上述结果表明在实验所设浓度范围内,甲醛对小鼠卵巢生殖细胞的DNA损伤可以引起DNA-蛋白质的交联,并且DPC系数随着染毒浓度的增大而增大.DNA-蛋白质交联是DNA分子的一种严重损伤,气态甲醛对雌性小鼠生殖细胞具有一定的影响.     

多壁碳纳米管对林丹的吸附和催化转化

进入环境的纳米材料对共存化学污染物的环境行为有重要影响.本文选择3种多壁碳纳米管,分别为石墨化多壁碳纳米管(G-MWCNT)、羟基化多壁碳纳米管(O-MWCNT)和氨基化多壁碳纳米管(N-MWCNT),通过批次实验研究其对林丹的吸附行为和催化转化作用.林丹在3种多壁碳纳米管上的吸附动力学符合准二级动力学模型(R20.997),吸附速率常数(k2)分别为0.73(G-MWCNT)、0.60(N-MWCNT)和0.28(O-MWCNT)g·mg~(-1)·h~(-1).林丹在3种多壁碳纳米管上吸附的等温线符合Freundlich经验模型(R20.979),不同p H条件下,吸附系数(KF)分别为28.0—30.0(G-MWCNT)、21.3—24.6(N-MWCNT)和9.1—10.2(O-MWCNT)mg1-n·Ln·g~(-1).平衡浓度为8.5 mg·L~(-1),在不同p H条件下林丹在3种多壁碳纳米管上的分配常数(Kd)分别为12.7—14.4(G-MWCNT)、8.7—9.8(N-MWCNT)和3.9—4.2(O-MWCNT)L·g~(-1).林丹是非离子型有机化合物,疏水作用在吸附过程中起主导作用,表面引入亲水性强的氨基和羟基后,N-MWCNT和O-MWCNT的吸附作用相比具有疏水性表面的G-MWCNT明显减弱.溶液的p H值(5.0—9.0)对同种多壁碳纳米管的吸附作用影响不显著.均相溶液中,林丹发生β-消去反应的准一级动力学表观速率常数kobs(0.017—10.2 d~(-1))随溶液p H值(7.0—12.0)升高而增大.N-MWCNT对林丹发生β-消去反应起催化作用,这种催化作用随p H值(7.0—9.0)升高而增强.当N-MWCNT存在时,林丹的去除率分别增加了7.5%(p H=7.0)、29.3%(p H=8.0)和30.1%(p H=9.0).在均相溶液和N-MWCNT体系中都检测到γ~(-1),3,4,5,6-五氯环己烯、1,2,4-三氯苯和1,2,3-三氯苯转化产物.     

四种常见纳米材料对骨代谢的影响

探讨4种常见纳米材料(单壁碳纳米管,多壁碳纳米管,纳米银,量子点)对小鼠骨代谢的影响.选取8周龄健康昆明小鼠给予不同剂量的上述4种纳米材料,各纳米材料分别设高、中、低剂量组,溶剂对照、离子对照组,以及阳性对照组,每周3次进行腹腔注射.用药6周后检测骨破坏情况、骨生物力学改变以及血清中钙的含量.结果显示,4种纳米材料与其...     

不同纳米材料作用下菲对鲫鱼的毒性效应

研究了纳米材料(多壁碳纳米管和纳米氧化锌)泄漏进入水环境后吸附多环芳烃(菲)对水生生态系统可能造成的影响及其影响机制,以便能及早采取相应的风险管理措施.实验结果表明,多壁碳纳米管(MWCNTs)显著降低了菲(Phe)在鲫鱼肌肉和肝脏中的富集,但增加了其在鱼脑中的富集量;C-Phe组菲在眼部、胚胎和生殖腺中含量均高于ZnO-Phe组.MWCNTs、nZnO与菲均诱导鲫鱼脑部和肝脏组织中自由基的生成.     

多壁碳纳米管对土壤微生物的生态毒理效应

以多壁碳纳米管为研究对象,从生化作用、酶活性、微生物数量和群落结构4个方面系统评估其对土壤微生物的影响。设置两组实验,分别为碳纳米管组和对照组。对于碳纳米管组,按1mg碳纳米管·g-1土的浓度将多壁碳纳米管与土样均匀混合,对照组中不加入多壁碳纳米管。定期(每28d)取样测定两组土壤中的各项生态毒理指标。近5个月的实验结果显示,不同指标对多壁碳纳米管的响应不同。土壤呼吸作用初期受抑制但后期恢复,氨化作用初期被促进但后期被抑制,脱氢酶活性发生增强和抑制两次波动,荧光素二乙酸酯酶活性在整个实验期间一直被抑制,微生物量出现先减少后增加再减少的规律,群落结构在实验初期和后期均有较大变化。总体上,多壁碳纳米管对土壤微生物表现了一定的生态毒性,但除荧光素二乙酸酯酶活性外,各毒理效应在统计意义上并不显著(0.05水平)。     

十溴联苯醚(BDE 209)孕哺期及出生后暴露对子代小鼠血液系统影响初探

本研究旨在探讨BDE 209长期暴露对出生后不同发育阶段子鼠血液系统的影响。将75只雌性昆明小鼠随机分为对照组、低剂量组(1.5 mg·kg-1·d-1)和高剂量组(225 mg·kg-1·d-1)。BDE 209暴露10 d后,将雌鼠与雄鼠合笼。选取怀孕时间相近(相差不过2 d)的10只孕鼠持续染毒直至自然分娩。出生后子鼠在哺乳期通过母乳染毒,断乳后则按照与母鼠相同的方式进行染毒,并在不同时间点进行外周血常规、外周血形态学、骨髓细胞形态学、骨髓细胞染色体组型和数目分析。血常规结果显示,低、高剂量BDE 209暴露对出生后不同发育阶段子鼠的白细胞计数没有影响,即白细胞、中性粒细胞、淋巴细胞及单核细胞的数量均无显著变化(P0.05);红细胞系统检查显示一定性别差异,即低剂量和高剂量BDE 209染毒的雄性小鼠在PND30出现红细胞(RBC)(P0.05)、血红蛋白(Hb)(P0.05或P0.01)及红细胞压积(P0.05或P0.01)的显著降低;而雌性小鼠只在PND 30出现红细胞压积的降低(P0.05);在PND 30,高剂量暴露组的雌性及雄性小鼠,低剂量暴露组的雌性小鼠均出现血小板计数的显著降低(P0.05或P0.01);而PND 60、PND 90的实验组血小板均未观察到显著改变(P0.05)。外周血形态学检查表明,低剂量组在PND 30、PND 60,及高剂量组在PND 90检测到典型异常结果多表现为白细胞数的增多。而低剂量组在PND 90检测到的典型异常结果多表现为异型深染淋巴细胞(P0.05)。骨髓形态学检测表明,低剂量组子代雄性及雌性小鼠在PND 60、PND 90骨髓涂片可检测到骨髓细胞的异常结果,表现为骨髓增生活跃,高剂量组雄性小鼠在PND 90观察到3例异常涂片,表现为骨髓增生异常(P0.05)。研究结果表明,BDE 209长期暴露可能导致出生子代外周血和骨髓的毒性,提示具有血液系统发育毒性。     

静脉注射多壁碳纳米管后大鼠脏器的病理学观察(Pathological Observations of Rat Tissues After Intravenous Injection of Mutil-Wall Carbon Nanotubes)

以Wistar大白鼠为研究对象,观察了多壁碳纳米管(MWNTs)体内暴露后脏器的病理学变化.采用尾静脉注射的方法将直径为40～60nm的多壁碳纳米管(40～60MWNTs)和直径小于10nm的多壁碳纳米管(10MWNTs)暴露于大白鼠体内,同时分别采用纳米二氧化硅(SiO2)和乙炔碳黑(Cb)作为阳性和阴性对照.实验结果表明:1、3、5mg·kg-1(以大鼠体重计)多壁碳纳米管进入大鼠体内90d后,大鼠心脏、肾脏、肝脏和胃结构正常,未见明显的病理损伤.但是多壁碳纳米管均可在大鼠肺部沉积,随着暴露时间的延长,多壁碳纳米管一部分被肺巨噬细胞清除体外,但是残余的多壁碳纳米管引起了肺部的病理学改变.     

Pharyngeal aspiration of single-wall carbon nanotubes aggravates allergic reaction to inhaled ovalbumin in mice

Single-wall carbon nanotubes are a major type of nano-objects that have industrial applications such as fuel cells. In this study, four types of single-wall carbon nanotubes and their abilities to aggravate allergic reactions were examined: those containing Fe, those containing Ni, and the corresponding purified metal-free ones. These were administered to mice via pharyngeal aspiration. Subsequently, the mice inhaled ovalbumin a total of eight times over three weeks. After inhalation of ovalbumin, the concentrations of total immunoglobulin E and ovalbumin-specific immunoglobulin E in serum increased in mice treated with purified metal-free and Fe containing single-wall carbon nanotubes while those containing Ni did not affect total and ovalbumin-specific immunoglobulin E levels. Additionally, the purified metal-free and Fe containing nanotubes caused the gene expression of heme oxygenase-1, chemokine (C-X-C motif) ligand 2, and tumor necrosis factor-α, suggesting that some kinds of single-wall carbon nanotubes have the potential to aggravate allergic reactions via oxidative stress and inflammation. Incorporated metals do not seem to be involved in the aggravation of allergic reactions. Other physical properties, such as fiber length and aggregation state, may be involved in enhancing allergic reactions.     

Construction of carbon nanotube-based microcapsules by self-assembly

Carbon nanotubes possess unique structures and outstanding properties. However, dispersion and manipulation of carbon nanotubes in solvents severely limit their application. A solution is building carbon nanotube-based microcapsules that combine both the properties of carbon nanotubes and capsules. Carbon nanotube-based microcapsules have indeed great potential applications including catalysts, adsorbents, and controlled-release materials. Here, we built carbon nanotube-based microcapsules by electrostatic self-assembly to develop novel composite materials. The construction and morphology of microcapsules were characterized by Raman spectroscopy, infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. Pre-films composed of poly(sodium 4-styrenesulfonate) and poly(diallyldimethylammoinum chloride) were assembled onto calcium carbonate (CaCO₃) microparticles to construct positive solid templates. The carboxylated carbon nanotubes were then successfully assembled on the CaCO₃ template using a self-assembly technique. Ethylene diamine tetraacetic acid (EDTA) was used as a powerful chelating agent to remove the CaCO₃ cores by chelation between EDTA and calcium, thus completing the construction of carbon nanotube-based hollow microcapsules. The spherical shapes of the microcapsules were well retained, and the carbon nanotubes were anchored evenly in the polyelectrolyte layers.     

Efficient preparation of greener N-doped carbon nanotube composites for water treatment by the microwave polyol method

N-doped carbon nanotubes have unique structures and strong interactions with metal nanoparticles due to the presence of nitrogen. There is actually a need for nanoparticles to treat water, without leaching of toxic metals. Here, we synthesized nanocomposites by deposition of Ag and Fe nanoparticles on N-doped carbon nanotubes with a surface area of 52 m²/g and 2 % N content to form nanocomposites. Transmission electron microscopy (TEM) of the nanocomposites revealed that the best dispersion of the deposited nanoparticles was achieved by the microwave-assisted polyol method. The Ag and Fe nanoparticles were indeed monodispersed and uniformly distributed on the surface of the N-doped carbon nanotubes. Deposition could be achieved in 5 min. The wet impregnation and deposition–precipitation methods gave composites with agglomerated nanoparticles. We observed that leaching of Fe and Ag into water was also influenced by the preparation method. No leaching of nanoparticles was observed when the composites were prepared by the microwave polyol method. This synthesis is therefore efficient with less energy and time. The strong metal/N-doped carbon nanotube interactions render these composites suitable for use in water purification.     

4种典型纳米材料对小鼠胚胎成纤维细胞毒性的初步研究

为探讨不同种类纳米材料对原代培养小鼠胚胎成纤维细胞(Mouse embryo fibroblasts,MEF)的毒性效应及作用机制,选择4种典型的纳米材料(纳米碳、单壁碳纳米管、纳米氧化锌、纳米二氧化硅)制备颗粒悬液,设立5个剂量组(5、10、20、50、100μg·mL-1)对BALB/c小鼠MEF细胞进行24、48、72h染毒培养,利用细胞形态学观察和噻唑蓝实验(MTT比色法)检测上述4种纳米材料对MEF细胞活性的影响,同时,测定染毒24h后细胞培养液上清中乳酸脱氢酶(LDH)活性以探讨纳米颗粒对细胞膜完整性的影响.结果显示:1)4种纳米材料均能明显影响MEF细胞的生长形态.染毒24h后,MEF细胞发生不同程度的回缩变形,细胞间隙增大,排列稀疏,胞内颗粒物增多,细胞透明度下降.2)纳米碳、纳米氧化锌、纳米二氧化硅对MEF细胞增殖的抑制作用和对细胞膜完整性的损伤作用均随染毒剂量的升高而增强,具有明显的剂量-效应关系,其半数致死浓度(24h-IC50)分别为21.85、21.94、461.10μg·mL-1;碳纳米管组的剂量-效应之间不呈对数线性关系,未能得出其24h-IC50.3)在不同染毒剂量水平上,4种纳米材料的毒性对比差异显著:低剂量水平上纳米碳与碳纳米管的毒性强于纳米氧化锌和纳米二氧化硅,随着剂量的升高纳米氧化锌的细胞毒性升高最为显著.结果提示,纳米材料能够对MEF细胞造成毒性损伤,破坏细胞膜的完整性可能只是作用途径之一;纳米材料的毒性可能受粒径、形状、化学组成等许多因素的影响.     

International standardized procedures for in vivo evaluation of multi-walled carbon nanotube toxicity in water

The classical approach in ecotoxicological evaluation of chemical substances consists of conducting standardized bioassays on organism models. In this work, the potential impact of industrial multi-walled carbon nanotubes was investigated by ecotoxicological standardized procedures using aquatic organisms of different trophic levels, namely bacteria, green algae, invertebrates, fish, and amphibians. The results indicated (1) inhibition of growth in amphibians at 50 mg L^?1 and higher, and (2) no effects on daphnia and fish up to 100 mg L^?1. With the exception of algae (for which Fe deficiency is measured), it seems that the observed toxicity may be due to physiological effects in relation to the ingestion of carbon nanotubes not necessarily related to their intrinsic effects.     

The role of thymoquinone as antioxidant protection on oxidative stress induced by imidacloprid in male and female Swiss albino mice

The aim of the present study was to evaluate the possible protective effects of thymoquinone (TQ), an antioxidant agent, against imidacloprid (IMI)-induced oxidative stress in male and female mice. In total, 48 Swiss Albino male and female mice were fed a standard rodent diet and divided into 3 equal groups: the animals in the control group (vehicle treated) were given corn oil, the second group were orally administered 15 mg/kg/day IMI alone, and the third group were orally administered 15 mg/kg/day IMI and with TQ at 10 mg/kg/day for 21 days. During the experimental period, there were no significant changes between initial body weights and final body weights of IMI treated male and female mice. IMI produced significant increase in blood, liver, kidney, and heart malondialdehyde (MDA) levels and decrease in blood and liver glutathione (GSH) levels. In addition, IMI treatment decreased erythrocyte, liver, and kidney superoxide dismutase (SOD) activity in male mice and decreased erythrocyte and liver SOD activity in female mice. Erythrocyte catalase (CAT) activities were found to be low in male and female mice. However, treatment with TQ reversed IMI-induced oxidative stress, lipid peroxidation, and activities of antioxidant enzymes. Moreover, TQ exhibited protective action against the IMI-induced histopathological changes in tissues of male and female mice. In conclusion, TQ was found to be effective in protecting mice against IMI-induced oxidative stress by enhancing antioxidant defense mechanisms.     

Patterns and ecological predictors of age-related performance in female North American barn swallows,Hirundo rustica erythrogaster

Life history theory describes the optimization of important trade-offs within an individual’s lifetime and predicts that an individual’s reproductive performance (RP) will improve up until a point of senescence. Despite abundant evidence for this pattern, relatively few studies consider the mechanisms associated with age-related improvements in RP. In this study, we aimed to describe patterns of age-related RP (seasonal fledgling production) in female North American barn swallows (Hirundo rustica erythrogaster) using a longitudinal data set to test multiple hypotheses about the social, morphological, and ecological factors underlying this prominent life history pattern. To address these objectives, we used generalized linear mixed models in a three-step series of analyses in which we assessed (1) patterns of female age-related RP; (2) the influence of age on changes in social, morphological, and ecological factors; and (3) whether the changes in RP were concomitant with changes in these factors. We found that (1) females showed patterns of age-related reproduction, in which performance increased in the first 2 years of breeding and decreased thereafter, (2) female tail streamer length increased and the extent of breast coloration increased then decreased significantly with age, and (3) changes in morphological traits did not covary with changes in reproductive performance over time. Our within-individual results highlight the importance of considering explicit links between morphology and reproductive performance that are not easily captured by population-level analyses.