Cr6+生物可利用度检测的微生物全细胞传感器CB10的构建及其响应特征

为实现重金属污染环境中Cr6+的生物可利用度评价,进而为Cr6+的污染治理提供可靠依据,本研究采用分子生物技术,以重金属广谱抗性菌株Cupriavidus metallidurans CH34的pMOL28质粒上铬抗性调控系统的启动子和调控蛋白基因为传感器调控元件,以北美萤火虫Photinus pyralis的萤火虫荧光素酶基因luc为报告基因构建了一种可对Cr6+生物可利用度进行检测的微生物全细胞传感器CB10,并探究了其在不同检测条下的响应特征.结果表明,微生物全细胞传感器CB10在30 min内即可响应一定浓度的Cr6+;其对Cr6+的检测最低限LOD为2μmol·L-1;当Cr6+的浓度为20～200μmol·L-1时,CB10的响应能力与Cr6+浓度线性相关,进而传感器CB10可对该范围内的Cr6+生物可利用度进行定量分析(R2=0.980 55);当重金属诱导浓度为10～50μmol·L-1时,CB10对Cr6+具有较强的响应特异性;本研究也发现,较高浓度的Pb2+、Mn2+和Sb2+也可以产生对CB10的诱导能力;诱导温度为30℃,pH为7时,CB10的响应效率最高;诱导温度为15～30℃,pH为4～7时,CB10响应能力表现稳定.CB10具备较强的响应速率、灵敏度、特异性和稳定性,具备对水体重金属进行快速检测和土壤重金属的生物可利用进行评价的潜力.     

红阳猕猴桃优良雄株选择初报

通过对优良雄性猕猴桃株系M1、M2、M3、M4、M5、M6、M7、M8的萌芽率、花期、花大小、花粉生活力以及授粉后对红阳猕猴桃果实品质的影响分析,认为M8是红阳猕猴桃的最适优良雄株.     

沙尘尺寸分布对微波传输特性的影响

应用沙尘粒子的尺寸分布和沙粒的等效介电常数模型,给出了微波在沙尘暴中的传输模型,表明沙尘的衰减和相移与沙粒的等效半径成正比关系,并对不同能见度、不同频率和不同高度下沙尘暴引起的衰减和相移进行了仿真计算。结果表明,对数正态分布和指数分布对微波的传输特性影响最大,瑞利分布和正态分布的预测结果比较接近且影响最小。     

Long-term monitoring and source apportionment of PM2:5/PM10 in Beijing, China

During 2001-2006,PM2.5 (particle matter with aerodynamic diameter less than 2.5 microns) and PM10 (particle matter with aerodynamic diameter less than 10 microns) were collected at the Beijng Normal University (BNU) site,China,and in 2006,at a background site in Duolun (DL).The long-term monitoring data of elements,ions,and black carbon showed that the major constituents of PM2.5 were black carbon (BC) crustal elements,nitrates,ammonium salts,and sulfates.These five major components accounted for 20%-80% of...     

重金属抗性菌Bacillus cereus HQ-1对银离子的生物吸附-微沉淀成晶作用

发现1株对银离子有强吸附能力的蜡状芽孢杆菌HQ-1,研究了其对银离子的吸附特性及吸附机理.结果表明,菌体对银的吸附量可达91.75 mg/g,吸附过程符合Pseudo-second Order吸附动力学模型,相关系数高达0.999 9;吸附热力学很好地符合Freundlich吸附等温模型,相关系数为0.99;考察菌体浓度和温度对吸附的影响发现,菌体浓度增加有利于对银离子的吸附,温度对吸附影响较小;FTIR、SEM及EDAX实验结果表明吸附存在2种吸附机理,一为菌体表面一些含氮氧的基团对Ag 的络合作用,二为菌体分泌的胞外多糖等物质对Ag 的微沉淀成晶作用.     

小球藻对养殖废水中N、P的去除研究

针对工厂化对虾养殖废水处理进行了初步研究,通过模拟试验进行小球藻N、P去除能力的探索.结果表明:被试藻类在水体中生长良好,小球藻能很好地去除水体的N、P,培养4 d后,水体中NH4-N的去除率达到80%以上、PO4-P的去除率达到85%以上;在适宜的温度、光照、pH值条件下,最适合小球藻生长的N/P值为8,小球藻的4 d增长量可以达到初始量的10倍.     

2种改性活性炭对甲苯吸附性能的对比研究

利用微波、电炉加热对活性炭进行改性,并测定了改性前后不同种类活性炭对甲苯的吸附性能、表面酸碱官能团含量以及比表面积.结果表明,对于微波改性,随着改性温度升高,活性炭对甲苯的吸附量逐渐增大,表面碱性官能团含量也相应增加,比表面积相应减小.改性温度850℃时活性炭吸附甲苯性能最高,650℃与450℃改性后活性炭吸附甲苯的性能相差不大.电加热改性也具有类似的趋势,但对甲苯的吸附性能总体低于微波改性.扫描电镜表征显示,热改性去除了活性炭孔道内的杂质,使活性炭内部孔道更加通畅,有利于提高吸附甲苯的能力,但温度升高同样存在炭骨架收缩,孔道变窄的弊端.微波加热和电炉加热在原理和热传递方向上的不同.是导致改性结果之间差别的关键问题.     

碳纳米管对阿特拉津的吸附/解吸特性

采用批量实验研究了不同溶液条件下阿特拉津(AT)在单壁碳纳米管(SWNT)和多壁碳纳米管(MWNT)上的吸附/解吸行为.实验结果显示,离子强度对AT在SWNT和MWNT上的吸附没有显著影响,但随着pH值的增大,AT在2种碳纳米材料上的吸附量显著增加;这表明,AT在溶液中的存在状态是吸附的主要影响因素.在本实验的研究条件下,AT从SWNT和MWNT上的解吸行为不存在明显的滞后效应.碳纳米管对AT较高的吸附容量和吸附的可逆性表明,碳纳米管的大规模应用将可能带来一定的环境和健康风险.     

Biotransfer of heavy metals along a soil-plant-insect-chicken food chain：Field study

The study investigated the accumulation and transfer of Pb,Zn,Cu,and Cd along a soil-plant-insect-chicken food chain at contaminated sites.The study site nearing the Pb/Zn mine had been contaminated by heavy metals severely.Cadmium and Pb concentrations steadily declined with increasing trophic level (p<0.01),but concentrations of Zn and Cu slightly increased from plant to insect larva (p>0.05).The concentrations of heavy metals were the highest in chicken muscle,with lower values in liver and blood.Bioaccumulation of Pb was observed in the chicken livers.The eliminations of Pb,Zn,Cu,and Cd via insect and chicken feces avoid metal bioaccumulation in insect and chicken body.These results suggest that the accumulation of heavy metals in specific animal organ of tissues could not be neglected,although transfer of metals to chicken from plant and insect is limited.     

Inhibitory effects of four plants flavonoids extracts on fatty acid synthase

Fatty acid synthase (FAS) had been found overexpress and hyperactive in most cancers. Pharmacological inhibitors of FAS activity preferentially repress cancer cell proliferation and induce cancer cell apoptosis without affecting nonmalignant fibroblasts. These made FAS an excellent drug target for cancer therapy. The activity of FAS in 11 different kinds of cancer cells, including esophageal carcinoma (EC109, EC8712, H5E973), gastric carcinoma (N87, BGC823), lung carcinoma (A549, 95-D), hepatoma (HepG2), uterine cervix cancer (HeLa) and leukaemia (K562, U937) were compared using spectrophotometric method. We selected the cell line with the highest FAS activity as cell model to study the inhibitory effect of the flavonoids extracts on FAS. Four plants including Canavium album Raeuseh leaves, Bombax ceiba Linn, Brassica albograbra Bailey, and Citrus reticulata Blanco were selected for extracting flavonoids. The results showed significantly different FAS activity among different cancer cells. The FAS activity is the lowest in gastric cancer cell N87 (15.91 ± 3.61 U/mg protein) and the highest in lung cancer cell A549 (127.36 ± 10.14 U/mg protein). The cancer cell A549 was used as cell model to test the inhibitory effort of flavonoids extracts on FAS. Results showed that the flavonoids extracts of Citrus reticulata Blanco and Canavium album Raeuseh leaves have higher inhibitory effect on FAS activity compared with the universally used FAS inhibitor C75 and both extracts inhibit cancer cell proliferation when added to cultured cancer cells. These studies provided a good cell model for testing the inhibitory effect on FAS activity and suggested that Citrus reticulata Blanco rind and Canavium album Raeuseh leaves are good biomaterials for separating and purifying natural flavonoids FAS inhibitors and exploring their inhibitory mechanisms.