钻井井场噪音对听觉系统影响的观察

对油田井场的特定部位进行声强测定及频谱分析,发现其噪声强度均已超过国家标准。选健康,耳廊反射正常豚鼠30只,分别置于柴油机旁（8只）,钻井平台（8只）和值班房（8只）,余6只为正常对照。每天暴露6h,连续21d,记录豚鼠脑干电位及扫描电镜下形态学改变,结果表明,虽然钻井平台上的噪音强度低于柴油机组,但它对人耳的损伤程度却高于柴油机组。     

13种樟科植物叶油细胞和粘液细胞的分布和结构的比较研究

利用组织透明法、石蜡制片法和薄切片法比较研究了樟科５属１３种植物叶片中油细胞和粘液细胞的分布和结构．结果表明：５属１１种植物叶片中有油细胞分布,其形状多为圆形,体积较小且大小基本一致,ｄ３０～４５μｍ;４属８种植物叶片中有粘液细胞分布,其形状多为椭圆形,体积较大,ｄ６０～１００μｍ．根据透明叶片观察,不同植物油细胞的分布密度不同;从叶片横切面观察,有些种油细胞分布于整个叶肉中,有的分布于栅栏组织与海绵组织之间及海绵组织中,有的仅分布于栅栏组织内．粘液细胞有些种分布于整个叶肉,而有的仅分布于栅栏组织中．因此,叶片内油细胞的分布密度、油细胞和粘液细胞的分布位置及其大小在种与种之间存在明显的差异,此种结构特征具有分类学上的意义     

基于协同反硝化脱氮的光伏废水处理

以光伏废水为研究对象,利用启动成功的协同反硝化反应器,在进水F-浓度为800mg/L,NO₃^--N为350mg/L的条件下,控制进水C/N为0.7左右,实现反硝化过程无需酸碱调控,TN去除率为90%以上,TN去除速率为2.0~2.5kg/（m³·d）.除氟试验表明,通过投加CaO初步除氟能将F-浓度降低至800mg/L,同时将pH提升至7.68,满足协同反硝化的pH范围（7.5~8.5）要求;二次除氟能有效降低废水中残余的F-及协同反硝化生成的SO₄^2-.针对多数含F-浓度超过800mg/L的光伏废水,可采用先初步除氟、协同反硝化脱氮,最终二次除氟、除硫酸盐的工艺路线.相比于完全异养反硝化脱氮处理光伏废水,采用协同反硝化可节约脱氮成本0.82元/t.     

彗星电泳法测定双酚A对雄性幼龄小鼠脑细胞的DNA损伤

双酚A是一种日常生活中无处不在的环境雌激素,具有生殖和神经毒性,但低剂量长期暴露对发育期青少年的危害性常常被低估或忽视。本研究以4周龄雄性清洁级小鼠为实验对象,以茶油作为溶媒对照,分别以双酚A浓度为0μg·m L-1、0.1μg·m L-1、10μg·m L-1和1 000μg·m L-1的茶油灌胃小鼠8周,然后利用彗星电泳法检测各组小鼠脑细胞的DNA损伤。结果显示,不同浓度双酚A暴露8周后,彗星电泳图像显示小鼠脑细胞DNA出现不同程度的损伤,随着暴露剂量的增加,带有彗尾的脑细胞比率从对照组小鼠的9.5%分别升高到暴露组小鼠的34.5%、36.0%和50.5%,细胞总体的尾部DNA含量、尾长和尾矩也都逐渐增加,而且各双酚A暴露组小鼠与溶媒对照组小鼠脑细胞都具有显著性差异(P0.01),这说明中长期双酚A暴露(包括低浓度环境暴露)会导致雄性幼龄小鼠脑细胞的DNA损伤。     

纳米硫化镉对A549细胞的损伤研究

研究纳米硫化镉(Nano-Cd S)材料对肺癌细胞系A549的毒性及氧化损伤作用。培养A549细胞,经传代后接种于6孔板中,每孔2 m L完全培养基,接种次日进行染毒。用直径20~30 nm、长度80~100 nm的Nano-Cd S进行染毒,染毒浓度分别为0、5、10、20、40和80 mg·L~(-1)。染毒24 h后用MTT检测细胞存活率,以存活率在80%左右的浓度为后续实验染毒浓度。应用流式细胞技术,用荧光探针法检测A549细胞的活性氧(reactive oxygen species,ROS)含量,PI-Annexin-V法检测细胞凋亡情况;用试剂盒检测细胞中超氧化物岐化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性以及丙二醛(malondialdehyde,MDA)含量,判断细胞氧化损伤情况。不同浓度Nano-Cd S处理细胞24 h之后,细胞存活率随剂量的增加而下降,浓度为10、20、40和80μg·L~(-1)时,存活率分别为(88.71%±0.80%)、(81.93%±3.06%)、(75.23%±1.13%)和(70.66%±5.63%),且各组间差异均具有统计学意义(P0.05)。以浓度为10和20 mg·L~(-1)的Nano-Cd S染毒24 h后,胞内ROS含量和细胞凋亡率随染毒剂量的增加而增加(P0.05);浓度为10 mg·L~(-1)时,细胞凋亡率为(6.26%±0.44%)。与对照相比,各染毒组SOD和CAT活性和MDA含量升高,20 mg·L~(-1)染毒组SOD和CAT活性和MDA含量高于10 mg·L~(-1)染毒组(P0.05)。研究表明,纳米硫化镉能引起A549细胞的氧化损伤和细胞凋亡,具有明显的细胞毒性。     

铜绿微囊藻与藻际细菌Ma-B1菌株的相互作用

藻与细菌通常共生于淡水生境,形成藻-菌共生体系,藻际细菌是水体生态系统中的重要组成部分,对藻的消长起重要的调控作用,但有关藻际微环境中藻与细菌的互作机制还不清楚. 采用传统的细菌平板培养方法,从太湖优势水华藻——铜绿微囊藻(Microcystis aeruginosa)细胞表面分离出一株藻际细菌Ma-B1,基于生理、生化试验和16S rRNA基因序列分析,初步鉴定为甲基营养芽孢杆菌(Bacillus methylotrophicus). 通过测定细胞生长,分析藻-菌相互作用机理. 结果表明:一定浓度(＞60 μg/mL)的Ma-B1的胞外代谢物可显著抑制铜绿微囊藻的生长(培养基为BG11,28 ℃/日,22 ℃/夜,3 000 lx,光暗比为14 h∶10 h);铜绿微囊藻的胞外滤液(500 μL/mL)对Ma-B1的生长有一定的促进作用,但其总滤液(500 μL/mL)显著促进Ma-B1的生长;Ma-B1细胞对铜绿微囊藻的生长没有显著影响,而高浓度(藻菌比10∶1)的铜绿微囊藻细胞则可显著抑制Ma-B1的生长. 铜绿微囊藻与Ma-B1之间存在复杂的相互抑制或促进关系,共同影响着藻、菌在自然水体生态系统中的消长.      

Royal jelly inhibited N-acetylation and metabolism of 2-aminofluorene in human liver tumor cells (J5)

The present study was carried out to evaluate the question of whether or not royal jelly affects N-acetylation and metabolism of 2-aminofluorene (2-AF) in the human liver tumor cell line (J 5). N-acetylation and metabolism of 2-AF in intact J5 cells was determined by using high performance liquid chromatography for the amounts of acetylated and nonacetylated 2-AF and profile of 2-AF metabolism. The results indicated that royal jelly displayed a dose-dependent inhibition of N-acetylation of 2-AF in J5 cells. Royal jelly also decreased the profile of 2-AF metabolites in J5 cells. This report is the first demonstration which showed that royal jelly affects N-acetylation of 2-AF in human liver tumor cells (J5).     

Determination of F2-isoprostanes in cultured human lung epithelial cells after exposure to metal oxide and silica nanoparticles by high-performance liquid chromatography/tandem mass spectrometry

The environmental impact of nanotechnology has caused a great concern. Many in vitro studies showed that many types of nanoparticles were cytotoxic. However, whether these nanoparticles caused cell membrane damage was not well studied. F₂-isoprostanes are specific products of arachidonic acid peroxidation by nonenzymatic reactive oxygen species and are considered as reliable biomarkers of oxidative stress and lipid peroxidation. In this article, we investigated the cytotoxicity of different nanoparticles and the degree of cellular membrane damage by using F₂-isoprostanes as biomarkers after exposure to nanoparticles. The human lung epithelial cell line A549 was exposed to four silica and metal oxide nanoparticles: SiO₂ (15 nm), CeO₂ (20 nm), Fe₂O₃ (30 nm), and ZnO (70 nm). The levels of F₂-isoprostanes were determined by using high-performance liquid chromatography/mass spectrometry. The F₂-isoprostanes’ peak was identified by retention time and molecular ion m/z at 353. Oasis HLB cartridge was used to extract F₂-isoprostanes from cell medium. The results showed that SiO₂, CeO₂, and ZnO nanoparticles increased F₂-isoprostanes levels significantly in A549 cells. Fe₂O₃ nanoparticle also increased F₂-isoprostanes level, but was not significant. This implied that SiO₂, CeO₂, ZnO, and Fe₂O₃ nanoparticles can cause cell membrane damage due to the lipid peroxidation. To the best of our knowledge, this is the first report on the investigation of effects of cellular exposure to metal oxide and silica nanoparticles on the cellular F₂-isoprostanes levels.     

Protective role of epigallocatechin 3-gallate against lead-induced toxicity in human neuroblastoma cells

Lead (Pb) is a heavy metal, known to induce oxidative stress and produce damage to the antioxidant defence system ultimately leading to cell death. Antioxidants such as epigallocatechin 3-gallate (EGCG), a green tea polyphenol, was shown to play a protective role during Pb-exposure. In this study, human SH-SY5Y neuroblastoma cells were exposed to different concentrations (0.01–10?µM) of Pb for 48?h to determine effects on the viability of cells. It was observed that IC₅₀ was at 5?µM and at this concentration the cells exhibited a significant increase in caspase-3 activity, an indicator of apoptosis at least by 10-fold and the decrease of 59.4% in glutathione (GSH) content. The total cellular prostaglandin-E₂ (PGE₂) level was found to be elevated at least 10-fold upon Pb exposure. However, the effects of Pb on cells pre-incubated with 50?µM EGCG followed by 5?µM Pb showed 40% inhibition in cell viability, 17.3% decrease in caspase-3 activity, 23% increase in GSH content, and 11.4% fall in PGE₂ levels when compared with cells exposed to Pb only. Data suggest that EGCG exerted a significant protection to cell viability in preventing cell death and elevation in levels of GSH in cells exposed to Pb. However, EGCG did not elicit any significant effect on release of PGE₂ indicating the nature of EGCG as an effective anti-apoptotic, antioxidant, and anti-inflammatory agent.     

Single walled carbon nanotubes induce cytotoxicity and oxidative stress in HEK293 cells

The aim of the present study was to evaluate the potential toxicity and general mechanisms involved in single walled carbon nanotubes (SWCNTs)-induced cytotoxicity using human embryonic kidney cell line (HEK293) cells. Carbon nanotubes (coded as CNT) used in this study were synthesized by the chemical vapor deposition method. To elucidate the possible mechanisms underlying SWCNT-induced cytotoxicity, cell viability, cell membrane damage (lactate dehydrogenase activity (LDH) assay), reduced glutathione (GSH), interleukin-8 (IL-8) and lipid peroxidation products levels were quantitatively assessed following SWCNT exposure for 48 hr using HEK293 cells. Exposure of cells to SWCNT at 3–300 μg/ml produced significant reduction in cell viability in a concentration-dependent manner. The IC₅₀ value of SWCNT was found to be 87.58 μg/ml. Exposure of HEK cells to SWCNT at 10–100 μg/ml resulted in concentration-dependent cell membrane damage, increased production of IL-8, elevated levels of thiobarbituric acid reactive substances like malondialdehyde and decreased intracellular GSH levels. In summary, exposure to SWCNT resulted in a concentration-dependent cytotoxicity in cultured HEK293 cells that was associated with increased oxidative stress.