hPARP-1基因cDNA翻译起始区域的T载体克隆

目的 克隆及构建含限制性内切酶位点BamHⅠ、SacⅠ的人聚腺苷二磷酸核糖聚合酶-1(hPARP-1)基因cDNA翻译起始区域的pGEM-T-S载体，为以后的亚克隆和毒理学研究提供实验材料。方法 采用RT-PCR方法，用正常人胚肺成纤维细胞(HLF)抽提的总RNA逆转录成cDNA，再以cDNA为模板，扩增hPARP-1基因片段，并直接与T载体连接后转化大肠埃希菌DH5α，用蓝(白)斑试验筛选出阳性克隆，抽提重组质粒并进行PCR及酶切鉴定，再行序列分析。结果 经RT-PCR获得507bp含限制性内切酶位点的阳性产物，T载体克隆、PCR及酶切鉴定和序列分析后证实，克隆片段与Genbank中该基因的序列同源性为99．9％。结论 该实验成功地构建了含hPAR-1基因cDNA翻译起始区域的T载体克隆，为亚克隆及缺陷细胞株的建立提供工具。     

丙型肝炎病毒IRES基因T载体克隆及序列分析

目的构建含丙型肝炎病毒（HCV）核糖体插入位点（IRES）序列的基因克隆,为以后的亚克隆和抑制肝炎病毒作用的研究提供实验材料。方法以含HCV全长基因的质粒为模板,用PCR技术扩增出HCV的IRES序列,将扩增产物IRES基因插入到PMD18T载体后转化DH5α,筛选阳性克隆,抽提重组质粒并进行PCR及酶切鉴定,再行序列分析。结果经PCR获得355bp含限制性内切酶位点的阳性产物,T载体克隆、PCR及酶切鉴定和序列分析后证实,克隆片段与GeneBank中该基因的序列同源性为99%。结论该实验成功构建了含HCV IRES基因序列的T载体克隆,提示该克隆是用作亚克隆和抑制肝炎病毒研究的理想克隆。     

丙型肝炎病毒核心蛋白基因克隆载体的构建

目的构建丙肝病毒(HCV)核心基因克隆载体PMD18T-HCV/core,为进一步研究将HCV核心蛋白的基因调节功能应用于构建可调控性表达载体治疗病毒性肝炎做好前期基础。方法将含HCV全长基因的pHCV质粒于大肠杆菌DH5α内扩增,提取pHCV质粒,从pHCV质粒中PCR扩增出HCV核心基因片段并将其插入PMD18T克隆载体得到PMD18T-HCV/core克隆载体,将PMD18T-HCV/core克隆载体转化DH5α,筛选阳性克隆,抽提重组质粒并进行PCR及酶切鉴定,再行序列分析。结果经PCR获得582bp含限制性内切酶位点的阳性产物,T载体克隆后,PCR、酶切鉴定及序列分析证实,克隆片段与GeneBank中该基因的序列同源性为97%。结论该实验成功构建了含HCV核心蛋白基因序列的T载体克隆,提示该克隆是用作亚克隆和抑制肝炎病毒研究的理想克隆。     

CYP1A1基因cDNA全长的T载体克隆及序列分析

目的构建含KpnI、XhoI双酶切位点的人细胞色素(CYP1A1)基因cDNA全长的pGEM-T载体,为以后的亚克隆和毒理学研究提供实验材料。方法从培养的人乳腺癌细胞(MCF-7)中抽提总RNA,RT-PCR扩增CYP1A1基因cDNA全长,与pGEM-T载体连接后转化DH5α,筛选阳性克隆,抽提重组质粒并进行PCR及酶切鉴定,再行测序分析。结果重组质粒pGEM-T-1A1 PCR后获得了1 568 bp产物,酶切鉴定证实目的片段成功插入至pGEM-T,测序分析也进一步证明了目的片段与GeneBank中CYP1A1mRNA的序列同源性为99.9%。结论成功地构建了含CYP1A1基因cDNA全长区域的T载体。     

小鼠睫状神经营养因子基因的克隆及真核表达载体的构建

目的：分别构建野生型和截短型小鼠睫状神经营养因子（CNTF）基因的真核表达载体。方法：通过逆转录聚合酶链反应（RT—PCR）扩增小鼠CNTF野生型全长编码序列，体外定点突变获取截短型CNTF的互补DNA（cDNA）编码序列．将上述两序列分别克隆至pGEM—T Easy载体，经限制性内切酶EcoRI和XbaI双酶切后，将野生型和截短型CNTF基因连入pTracer—CMV真核表达载体，DNA测序鉴定。结果：PCR成功扩增了野生型和截短型CNTF基因，DNA序列分析证实两种真核表达载体中的CNTF序列与GeneBank中目的序列一致。结论：野生型和截短型CNTF基因真核表达载体的成功构建为视网膜色素变性（RP）的基因治疗研究奠定了基础。     

含MGMT及增强荧光蛋白真核表达载体的构建

目的 克隆O^6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）基因,测序鉴定正确后构建含增强荧光蛋白（EGFP）的真核表达载体.方法 利用RT-PCR从人正常肝细胞中克隆MGMT并与克隆载体pGEM-T载体相连接.经PCR、酶切及测序鉴定证明克隆成功后用限制性内切酶切下MG-MT片段,同时酶切载体pIRES2-EGFP.凝胶纯化回收后重组构建真核表达载体并鉴定.结果 测序结果显示所克隆的编码序列与GeneBank公布MGMT cDNA序列一致.真核表达载体的PCR及酶切鉴定结果与预期结果一致.结论 成功克隆了耐药基因MGMT并构建了含EGFP编码序列的真核表达载体pIRES2-MGMT-EGFP,为MGMT的进一步相关研究奠定了坚实基础.     

慢性髓性白血病bcr/abl融合基因的克隆与表达

目的：克隆bcr／abl融合基因融合位点基因片段。方法：以慢性粒细胞白血病（CML）K562细胞株总RNA作为模板,采用RT—PCR方法扩增包含Bcr／abl（b3a2）融合位点基因片段。将RT—PCR物按正确的阅读框架,定向克隆到pEGFP—N3的下游,将重组质粒转化大肠杆JM109大肠杆菌,用PCR初筛,将PCR扩增阳性的重组子用EcoR Ⅰ和BamH Ⅰ双酶切鉴定,并进行序列的测定。结果：扩增出470bp的Bcr／abl融合位点基因片段,构建重组质粒pEGFP—bcr／abl,酶切产物的大小分别与预期相符。结论：成功地扩增bcr／abl融合位点基因片段及构建真核表达重组质粒pEGFP—bcr／abl,为在体外表达重组bcr／abl蛋白奠定基础。     

DSB修复基因hKu70反义RNA真核表达载体构建

目的 构建人DNA双链断裂（DSB）修复基因hKu70反义RNA真核表达载体pEGFP-C1-K，为以后的hKu70基因功能和毒理学研究提供实验材料。方法 提取人胚肺成纤维细胞（HLF）总RNA，逆转录酶-多聚酶链式反应（RT-PCR）扩增hKu70基因cDNA保守序列，经与pGEM-T载体连接，筛选，克隆，抽提质粒和双酶切后，将纯化的hKu70基因cDNA保守序列反向插入绿色荧光蛋白表达载体pEGFP-C1中，筛选，克隆，抽提质粒，从而构建hKu70基因反义RNA真核表达载体pEGFP-C1-K。结果 经RT-PCR获得467bp含限制性内切酶位点的DNA片段，T载体克隆后经双酶切，测序，确定该片段为hKu70基因cDNA，进而构建反义RNA真核表达载体pEGFP-C1-K，并双酶切，测序确证。结论 成功构建hKu70基因反义RNA真核表达载体pEGFP-C1-K，为建立该基因低表达细胞株，DNA双链断裂修复缺陷和有关毒理学研究提供工具。     

抗人膀胱癌单克隆抗体重链可变区基因的克隆及原核表达载体的构建

目的 克隆抗人膀胱癌单克隆抗体重链可变区基因(VH),并构建其原核表达载体.方法 从能分泌抗人膀胱癌单克隆抗体的杂交瘤细胞BDI-1中提取总RNA,通过RT-PCR扩增出VH cDNA,用HindⅢ和XhoⅠ酶切纯化的RT-PCR产物和原核表达载体pET28a( ),在T4 DNA连接酶作用下室温连接.重组质粒经酶切鉴定,阳性克隆测序并进行序列分析.结果 扩增出VH cDNA片段,大小约为370bp,重组质粒的酶切鉴定结果与预期一致.VH基因序列长度为366bp,编码122个氨基酸.VH基因属于鼠免疫球蛋白重链Ⅱ亚类.结论 成功克隆出抗人膀胱癌单克隆抗体重链可变区基因,并成功构建其原核表达载体.     

Livin shRNA慢病毒载体的成功构建及鉴定

目的构建携带livin基因短片段发卡RNA（livin shRNA）的慢病毒载体。方法针对已经筛选确定的干扰人livin基因的有效靶序列,设计、合成靶序列的寡聚脱氧核苷酸DNA序列（OligoDNA）,退火形成双链DNA,与经HpaⅠ和XhoⅠ酶切后的携带U6启动子和绿色荧光蛋白的pGCL—GFP载体连接产生短片段发卡RNA慢病毒载体,PCR筛选阳性克隆,测序鉴定。结果PCR鉴定与DNA测序证实合成的含livin shRNA慢病毒载体寡核苷酸链插入正确。结论成功构建人livin shRNA慢病毒载体。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

---

Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.