四种环境雌激素对斑马鱼内脏团抗氧化防御系统的影响研究——17B-雌二醇与三种增塑剂DMP、DBP、DOP的影响

以斑马鱼(Danio rerio)为受试动物,研究了四种环境雌激素-17β-雌二醇(E2)和三种增塑剂(DMP、DBP、DOP)对其内脏团的氧化损伤及应激效应。经急性毒性实验,得到E2、DMP、DBP、DOP对成体斑马鱼96 h的半数致死浓度(LC50)分别为2.51、12.33、9.67、9.89 mg·L-1。在此基础上分别设置5个浓度梯度,研究E2(暴露2 d,4 d)、DMP、DBP、DOP(暴露4 d)对斑马鱼内脏团的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽硫转移酶(GST)活性以及丙二醛(MDA)含量的影响。结果表明,SOD、CAT、GST、MDA对这四种环境激素都非常敏感,其中SOD、CAT、GST活性的影响均呈现先诱导后抑制的趋势,而MDA含量则随着污染物浓度的升高而增加。高浓度暴露条件下,E2(0.4 mg·L-1)和DMP、DBP、DOP(0.8 mg·L-1)对SOD、CAT、GST活性均有显著抑制(p0.05),MDA的含量有显著升高(p0.05)。可见,E2、DMP、DBP、DOP会导致斑马鱼内脏团氧化损伤,并且在同等浓度下E2的毒性明显高于三种增塑剂。     

二氧化硫对心肌细胞线粒体损伤的分子机制探讨

采用Wistar大鼠作为模型进行整体动物动式吸入染毒,在大鼠吸入不同浓度SO2(0、7、14、28 mg·m-3,7 d,6 h·d-1)后,采用荧光定量PCR技术检测心肌细胞中由线粒体DNA(mtDNA)编码的细胞色素C氧化酶和ATP合酶的几种亚基及调控线粒体呼吸链组分的核转录因子PGC-1α、NRF-1和mtTFA的mRNA水平.结果发现,SO2染毒后,随着SO2浓度的升高,大鼠心肌中细胞色素C氧化酶3种亚基(CO1、CO2、CO3)和ATP合酶两种亚基(ATP68)mRNA表达水平均显著降低,调控基因PGC-1α、NRF1和mtTFA的mRNA表达水平也显著降低.提示大鼠吸入SO2后,可能通过降低心肌中PGC-1α表达,影响其与NRF1结合及对mtTFA调控,进一步抑制线粒体基因组的转录,最终可能使大鼠心肌线粒体的氧化磷酸化功能受损,进而引起心衰等心血管疾病.     

睾丸酮丛毛单胞菌PhaR基因敲除菌株的构建及其3, 17β-HSD对甾族化合物的响应特性

基于同源重组原理构建了PhaR基因敲除的睾丸酮丛毛单胞菌基因工程菌,并对不同诱导条件下菌体细胞的3,17β-羟基类固醇脱氢酶(3,17β-HSD)的表达情况进行了研究.结果表明,利用电穿孔法获得了一株PhaR基因插入失活的睾丸酮丛毛单胞菌突变体PK-4,该突变菌株具有较高的遗传稳定性.建立的ELISA法对3,17β-HSD表达的定量分析表明,睾丸酮丛毛单胞菌的野生株和突变株细胞内的3,17β-HSD蛋白都可被睾丸酮诱导,但不能被雌二醇和胆固醇诱导.在诱导条件下,突变菌株PK-4产生的3,17β-HSD蛋白量是野生型菌株产生量的2.6倍,并且在无诱导条件下,前者的量也明显高于后者,表明PhaR为3,17β-HSD基因表达的抑制子.雌二醇和胆固醇可明显抑制睾丸酮对睾丸酮丛毛单胞菌3,17β-HSD的诱导效应,但在相同条件下,睾丸酮丛毛单胞菌PhaR基因敲除的突变菌株PK-4产生的3,17β-HSD蛋白量仍然明显高于野生型菌株.说明,PhaR基因在睾丸酮丛毛单胞菌的3,17β-HSD表达调控方面具有重要意义,并且PhaR基因敲除的睾丸酮丛毛单胞菌基因工程菌PK-4在雄性激素污染物的环境污染治理方面还具有潜在的应用价值.     

Comparison of biochemical characteristics between PAO and DPAO sludges

A successful enhanced biological phosphorus removal(EBPR) was observed in both anaerobicaerobic sequencing batch reactor(An-Ox SBR) to induce growth of phosphorus accumulating organism(PAO) and anaerobic-anoxic(An-Ax) SBR to induce growth of denitrifying PAO(DPAO).Although the EBPR performance of An-Ox SBR was higher by 11.3% than that of An-Ax SBR,specific phosphorus release rates in the An-Ax SBR(22.8 ± 3.5 mg P/(g VSS·hr)) and the An-Ox SBR(22.4 ± 4.8 mg P/(g VSS·hr)) were similar. Specific phosphorus uptake rates under anoxic and aerobic conditions were 26.3 ± 4.8 mg P/(g VSS·hr)(An-Ax SBR) and 25.6 ± 2.8 mg P/(g VSS·hr)(An-Ox SBR), respectively, which were also similar. In addition, an analysis of relationship of poly-β-hydroxyalkanoates(PHA) synthesized under anaerobic conditions with phosphorous release(Preleased/PHAsynthesized) and of PHA utilized under anoxic and aerobic conditions with phosphorous uptake(Puptaked/PHAutilized) verified that biological activities of EBPR per unit biomass between DPAO and PAO were similar. An analysis of the specific denitrification rate of DPAO showed that NO-3-N can be denitrified at a rate that does not substantially differ from that of an ordinary denitrifier without additional consumption of organic carbon when the PHA stored inside the cell under anaerobic conditions is sufficiently secured.     

Mitochondrial electron transport chain is involved in microcystin-RR induced tobacco BY-2 cells apoptosis

Microcystin-RR （MC-RR） has been suggested to induce apoptosis in tobacco BY-2 cells through mitochondrial dysfunction including the loss of mitochondrial membrane potential . TO further elucidate the mechanisms involved in MC-RR induced apoptosis in tobacco BY-2 cells, we have investigated the role of mitochondrial electron transport chain （ETC） as a potential source for reactive oxygen species （ROS）. Tobacco BY-2 cells after exposure to MC-RR （60 mg/L） displayed apoptotic changes in association with an increased production of ROS and loss of Am. All of these adverse effects were significantly attenuated by ETC inhibitors including Rotenone （2 μmol/L, complex I inhibitor） and antimycin A （0.01 μmol/L, complex III inhibitor）, but not by thenoyltrifluoroacetone （S μmol/L, complex Ⅱinhibitor）. These results suggest that rnitochondrial ETC plays a key role in mediating MC-RR induced apoptosis in tobacco BY-2 cells through an increased mitochondrial production of ROS.     

水介质中C60纳米晶体颗粒与Cu2+对小鼠腹腔巨噬细胞的复合毒性研究

为考察C60纳米晶体颗粒和Cu2+复合体系的生物毒性,本文以小鼠腹腔巨噬细胞RAW264.7作为受试对象,研究了C60纳米晶体颗粒物(n C60)和Cu2+对RAW 264.7的复合毒性影响.结果表明,当单独暴露n C6024 h,n C60浓度为6.6 mg·L-1时,细胞活性降低了45%,n C60浓度为9.9 mg·L-1时,细胞活性降低了70%,表现出剂量-毒性效应和时间-毒性效应.水中出现Cu2+可以降低n C60的细胞毒性,当Cu2+浓度为2 mg·L-1,n C60浓度为6.6 mg·L-1时,细胞的活性降低至25%,当Cu2+浓度为5 mg·L-1,n C60浓度为9.9 mg·L-1时,细胞的活性下降至15%.研究表明,n C60表面能够吸附Cu2+,并且吸附符合Langmuir吸附等温模型.n C60纳米晶体颗粒表面对Cu2+的吸附,可能是n C60对细胞毒性降低的重要原因.     

班前安全会要做到"实、细、活、精"

班组是企业的细胞,是实施安全管理的重要场所和基本单位,开好班组安全会,是搞好班组安全生产的重要一环.通过形式多样、生动活泼的班前安全会,可以及时提醒组员注意安全,抓好安全,做好安全,取得事半功倍的效果.     

癌症疫苗失效的元凶浮出水面

英国研究人员在11月4日出版的《科学》杂志上撰文指出,在老鼠身上进行的研究表明,纤维母细胞活化蛋白（FAP）会阻止身体的免疫细胞去攻击癌细胞,破坏FAP可让肿瘤细     

中小学生物学课程中细胞生物学重要概念的筛选及表述

概念并不是孤立存在的,概念之间有着紧密的联系。采用国际比较研究法,我们筛选并梳理出中小学生物学课程中细胞生物学的重要概念及支撑它们的下位概念,并以命题的形式表述,体现出概念教学的循序渐进性,为我国中小学生物学的教学实践提供进一步参考,也为高中生物学课程标准修订"凸显重要概念传递"及教材的编写提供可借鉴的素材。