大肠杆菌吸附-化学还原法用废含金催化剂制备金纳米线

采用大肠杆菌吸附-化学还原法,以大肠杆菌(ECCs)为模板、十六烷基三甲基溴化铵为保护剂、抗坏血酸为还原剂,由废含金催化剂制备金纳米线(AuNWs)。采用XRD,SEM,TEM等技术对AuNWs进行表征。研究了AuNWs对罗丹明6G(R6G)和4-巯基苯甲酸(4-MBA)的拉曼散射信号的增强效果。实验结果表明:在制备过程中加入微生物ECCs,可使金回收率提高约20百分点;当溶液pH小于4时,反应2 h后,有大量呈线状的AuNWs聚集沉降,金回收率可达99%1以上。表征结果显示,AuNWs呈多晶结构,晶格间距为0.23 nm。表面增强拉曼散射分析表明,AuNWs对R6G和4-MBA具有良好的拉曼光谱增强性能。     

Isolation and Identification of Enterococci from Seawater Samples: Assessment of Their Resistance to Antibiotics and Heavy Metals

A hundred Enterococcus strains were isolated from seawater samples collected from coastal areas of Istanbul. Isolates were identified to the species level using standard biochemical tests specified by Facklam and Collins. The species distribution was as follows Enterococcus faecalis (96%), Enterococcus gallinarum (3%) and Enterococcus solitarius (1%). The resistance of bacteria to both heavy metals (zinc [Zn], iron [Fe], cadmium [Cd], chrome [Cr], cobalt [Co]) and antibiotics (ampicillin 10 μg [AP], penicillin G 10 Units [PG], gentamycin 10 μg [GM], streptomycin 10 μg [S], chloramphenicol 10 μg [C], erythromycin 15 μg [E], kanamycin 30 μg [K], amikacin 30 μg [AK], nalidixic acid 30 μg [NA], and vancomycin 30 μg [VA]) was evaluated. None of the strains was resistant to VA. It was found that among the 100 isolates, those that exhibit resistance to antibiotics, particularly NA, S and K, were also resistant all the heavy metals tested. To our knowledge this is the first report focusing on determination of resistance of environmental enterococci found in Istanbul against heavy metals and antibiotics. Thus, combined expressions of antibiotic and heavy metal resistance may help to reinforce ecological and epidemiological studies and to determine the role of these strains in antibiotic and heavy metal resistance dissemination.     

Fecal source tracking by antibiotic resistance analysis on a watershed exhibiting low resistance

The ongoing development of microbial source tracking has made it possible to identify contamination sources with varying accuracy, depending on the method used. The purpose of this study was to test the efficiency of the antibiotic resistance analysis (ARA) method under low resistance by tracking the fecal sources at Turkey Creek, Oklahoma exhibiting this condition. The resistance patterns of 772 water-isolates, tested with nine antibiotics, were analyzed by discriminant analysis (DA) utilizing a five-source library containing 2250 isolates. The library passed various representativeness tests; however, two of the pulled-sample tests suggested insufficient sampling. The resubstitution test of the library individual sources showed significant isolate misclassification with an average rate of correct classification (ARCC) of 58%. These misclassifications were explained by low antibiotic resistance (Wilcoxon test P < 0.0001). Seasonal DA of stream E. coli isolates for the pooled sources human/livestock/deer indicated that in fall, the human source dominated (P < 0.0001) at a rate of 56%, and that human and livestock respective contributions in winter (35 and 39%), spring (43 and 40%), and summer (37 and 35%) were similar. Deer scored lower (17–28%) than human and livestock at every season. The DA was revised using results from a misclassification analysis to provide a perspective of the effect caused by low antibiotic resistance and a more realistic determination of the fecal source rates at Turkey Creek. The revision increased livestock rates by 13–14% (0.04 ≤ P ≤ 0.06), and decreased human and deer by 6–7%. Negative misclassification into livestock was significant (0.04 ≤ P ≤ 0.06). Low antibiotic resistance showed the greatest effect in this category.     

具有LXRα活性效应物质的新型筛查方法研究

为了检测环境中潜在的LXRα效应物质.本研究以LXRα蛋白为例,利用核受体蛋白与小分子亲和结合的原理,构建了pCold-TF-LXRα重组蛋白并优化了重组蛋白的表达条件,建立了特异性捕获活性物质的方法.结果表明：诱导温度为20℃、诱导剂IPTG浓度为0.4mmol/L为重组蛋白的最佳表达条件;同时,利用LXRα激动剂T0901317 4个梯度浓度（0.25,2.5,25,250μg/L）的加标回收率实验测得线性回归曲线为y =0.83604x+0.40763,R²=0.9948,证明方法具有有效性;对比pCold-TF空载体蛋白（6.42%）和重组蛋白（79.83%）对T0901317（250 μg/L）的回收率,说明方法具有特异性.为了验证方法的实用性,将重组蛋白与15种典型的有机磷酸酯类化合物（OPEs）的混合标样进行“捕获”实验,证明了TPHP、BPADP、TCrP、EHDPP、TNBP、RDP、TEHP、TDCIPP具有LXRα的活性效应.最后,用酵母双杂交实验验证了这8种OPEs均为LXRα的拮抗剂.     

HPLC法测定饲料中维生素A、维生素D 3 和维生素E

建立了以w(C2H5OH)=95 %乙醇直接提取,高效液相色谱仪在波长280 nm和254 nm处连续测定饲料中维生素A、维生素D3和维生素E的方法.色谱柱为大连依利特Hypersil ODS C18(25 cm×4.6 mm×5 μm),流动相为甲醇-水,流速为1.2 mL/min.维生素A、维生素D3、维生素E的质量浓度分别在1.0 mg/L～20.0 mg/L、0.5 mg/L～15.0 mg/L 、2.5 mg/L～50.0 mg/L范围内与峰面积呈良好的线性关系,检测限分别为0.3×10-6 μg、0.04×10-6 μg、5.0×10-6 μg,相对标准偏差分别为1.6 %、2.7 %、2.4 %,平均回收率分别为99 %、102 %、98 %.     

Using Multiple Antibiotic Resistance and land use characteristics to determine sources of fecal coliform bacterial pollution

Multiple Antibiotic Resistance (MAR) analysis and regression modeling techniques were used to identify surface water areas impacted by fecal pollution from human sources, and to determine the effects of land use on fecal pollution in Murrells Inlet, a small, urbanized, high-salinity estuary located between Myrtle Beach and Georgetown, South Carolina. MAR analysis was performed to identify areas in the estuary that are impacted by human-source fecal pollution. Additionally, regression analysis was performed to determine if an association exists between land use and fecal coliform densities over the ten-year period from 1989 to 1998. Land-use variables were derived using Geographic Information System (GIS) techniques and were used in the regression analysis.MAR analyses were conducted by comparing the frequency and patterns of antibiotic resistance found in Escherichia coli isolates derived from surface water samples and from sewage sources in the Murrells Inlet sewage collection system. The MAR results suggest that the majority of the fecal pollution detected in the Murrells Inlet estuary may be from non-human sources, including fecal coliforms isolated from areas in close proximity to high densities of active septic tanks.A MAR Index, which measures the frequency of antibiotic resistance, was calculated for each of twenty-three water samples and nine sewage samples. The antibiotic resistance pattern comparisons were performed using cluster analysis. Although the MAR indices indicated that several surface water sites had potential human-source contamination, the cluster analysis suggests that only one sampling site had MAR patterns that were similar to those found in the sewage samples. This site was in close proximity to several large pleasure boats as well as a sewage collection system lift station, but was not near areas with active septic tanks. The results of the regression analysis also suggest that sewage sources and rainfall runoff from urbanized areas may contribute to fecal pollution in the estuary.     

紫外线消毒中的光复活作用

近年来，紫外线消毒技术在水处理中得到了越来越广泛的应用，它主要是利用短波紫外对微生物的伤害作用，通过在DNA中形成环丁烷嘧啶二聚体，阻碍基因的正常复制，从而导致细菌失活。但是细菌体内的光裂解酶在远紫外光和可见光作用下能够使失活的细菌重新获得活性，这就是光复活作用。低压消毒设备处理后大肠杆菌表现出了一定的光复活能力，但中压消毒设备能够有效的抑制其光复活作用；而噬肺军团菌在低压和中压设备处理后都表现出了很强的光复活能力。在应用紫外线消毒技术时光复活作用的影响不容忽视。     

软式排球健身价值的研究

运用文献、调查访问、观察、实验、统计及分析等研究方法,对有、无排球技术基础学生的对比分析,探讨软式排球的健身价值。研究结果表明:软式排球较硬式排球技术更易学习掌握,更易在学生中组织比赛,有着很重要的健身价值。为使软式排球更具有健身和娱乐性,应在比赛中灵活制定比赛规则。     

凤眼莲根系分泌物对栅藻结构及代谢的影响

研究了凤眼莲（Ｅｉｃｈｈｏｒｎｉａ ｃｒａｓｓｉｐｅｓ）根系分泌物对栅藻（Ｓｃｅｎｅｄｅｓｍｕｓ ａｒｃｕａｔｕｓ Ｌｅｍｍ）超微结构及生长代谢的影响，结果显示，凤眼莲对栅藻有明显的克生作用，藻的数量逐步减少，栅藻生长受影响后，细胞中绿体片层肿用甚至解体，线粒体嵴消失，质膜、核膜受破坏，光合放氧化速度明显下降，可溶性蛋白折含量四天后４线下降，超氧阴离子（Ｏ２－）、丙二醛（ＭＤＡ）的含量上升，知值都     

UV/O3复合降解水中2,4-二氯酚的试验研究

以紫外光源为主要依托,变换反应器中的不同工艺条件,分别对紫外光、臭氧和紫外/臭氧三种不同于工艺条件对水中污染物2,4-二氯酚(2 ,4-DCP)的降解规律进行研究.结果表明,UV/O3复合对2,4-DCP的降解较UV、O3单独作用效果好;溶液的酸碱度影响UV/O3对2 ,4-DCP的降解;此外,溶液中含有细菌时,E. coli的杀灭效果仍表现为UV/O3＞O3＞UV.细菌的杀灭和2,4-DCP的降解均消耗羟基自由基,形成竞争反应,从而影响到2,4-DCP的降解效果.