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Pamela J. Hatton Ian Cummins Lindsey J. Price David J. Cole Robert Edwards 《Pest management science》1998,53(3):209-216
Glutathione transferases (GSTs) catalysing the conjugation of 1-chloro-2,4-dinitrobenzene, the chloro-s-triazine herbicide atrazine, the chloroacetanilide herbicides metolachlor and alachlor and the diphenyl ether herbicide fluorodifen have been identified in suspension-cultured cells derived from the grass weed giant foxtail (Setaria faberi Herrm.). In contrast to suspension-cultured cells of maize, where atrazine-conjugating GSTs are lost during de-differentiation, the GSTs active toward this herbicide in S. faberi plants were also expressed in cultures, suggesting that these isoenzymes are subject to different regulation in the crop and weed. As a result, glutathione conjugation was the major route of atrazine metabolism in S. faberi cultures. Activities of these GSTs were maximal three days after sub-culturing when the cells were dividing most actively, when they were determined to be in the order CDNB>alachlor>metolachlor= fluorodifen>atrazine. This indicated that GSTs which are enhanced during cell division can metabolise herbicides. On the basis of activity per mg protein, GST activities in the cultures were between 20 and 60-fold higher than those determined in the foliage of S. faberi seedlings. The GSTs with activity towards CDNB were resolved into three peaks following anion-exchange chromatography at pH 7·8 using Q-Sepharose. Peak 1 GSTs were not retained, while peak 2 and peak 3 were sequentially resolved with an increasing concentration of salt. Peak 1 GSTs showed activity toward metolachlor and atrazine but showed little activity toward fluorodifen. Peak 2 and peak 3 GSTs were active toward atrazine and metolachlor, with peak 3 being particularly associated with activity toward fluorodifen. The GSTs in these peaks were then further purified using S-hexyl-glutathione-agarose affinity chromatography. In each case, the affinity-bound fraction of the GSTs consisted of 28 kDa and 26 kDa polypeptides, suggesting that the GST isoenzymes in S. faberi cultures are composed of related subunits. Our results demonstrate that the GST isoenzymes involved in herbicide metabolism in suspension cultures of a grass weed show a similar level of complexity to that determined in maize cell cultures. © 1998 SCI 相似文献
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假单胞菌JK45菌株lux基因标记及在土壤中的存活 总被引：11，自引：0，他引：11
为研究植物根部重要促生菌株的个体生态学,利用三亲接合法成功地将发光酶基因luxAB转入具有解钾能力的假单胞菌Pseudomonassp.JK45菌株中。研究表明,获得的标记菌株JK45-L具有发光活性和对Cm、Km、Tet3种抗生素的抗性,杂交比例以1∶1∶1适宜。JK45-L菌株在抗生素平板中传代15次,仍具发光活性和对3种抗生素的抗性,说明标记质粒在受体菌株中较为稳定,JK45-L菌株的生长及生理生化特性没有受到标记质粒的影响,其解钾能力也没有发生明显的变化。将JK45-L菌株接种到土壤中利用luxAB基因的活性研究菌株的存活情况,结果发现,标记菌株在灭菌土壤和自然土壤中均能很好的生存,在黄褐土和黄潮土中存活规律相似,说明JK45-L菌株具有在不同土壤中与土著菌株进行空间和营养竞争的能力。 相似文献
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从2014年和2016年保存的来自河南、广东、山东和湖北4个省1 100株食品动物肠道大肠杆菌中筛选出58株blaCTX-M-27阳性菌株,采用药敏试验测定产blaCTX-M-27的大肠杆菌对20种抗生素的敏感性,并用PCR的方法检测其所携带的其他耐药基因;通过脉冲场凝胶电泳分析各菌株之间的亲缘关系,通过接合或转化试验、复制子分型和Southern blot对携带blaCTX-M-27的质粒特征进行分析。结果显示,58株blaCTX-M-27阳性大肠杆菌对除了β-内酰胺类外的其他抗生素,尤其氟喹诺酮类呈现高水平耐药;大多数菌株还同时携带2~3种编码其他抗生素的耐药基因。PFGE分型结果表明,来源于同一采样地及不同省的菌株存在克隆现象,但不同省或来自于同一省份的不同采样地之间的菌株亲缘关系较远;菌株携带的blaCTX-M-27基因全部定位在质粒上,其中38株位于可接合的IncFIB质粒,另外20株位于不可分型的质粒。 相似文献
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One sheep was dosed over 4 consecutive days with 2.1 kg of leaves and flower stems of Narthecium ossifragum before it was killed. Sarsasapogenin and smilagenin glycosides, in the ratio 9:1, were the dominant saponins present in the dosed plant material. GC-MS analyses of the free and conjugated sapogenin content of samples recovered from the sheep identified three distinct regions of metabolic activity. In the first metabolic region, in the rumen and omasum, the ingested plant saponins were hydrolysed to the parent sapogenins, before being oxidized at C-3 and reduced to give the epi analogues of the ingested sapogenins. The second metabolic region consisted of the duodenum, jejunum, the liver and associated ducts. Sapogenins appear to be absorbed in the jejunum and may be transported via the portal vein to the liver, where 3-OH-5-H sapogenins (epismilagenin and episarsasapogenin), but not 3-OH-5-H sapogenins (smilagenin and sarsasapogenin), are conjugated and excreted into the bile as episarsasapogenin and epismilagenin conjugates in the ratio 4:1. In the third metabolic region, in the caecum and the colon, the epi-sapogenin conjugates were hydrolysed to free epi-sapogenins. The absence of free and/or conjugated sapogenins in urine, collected 24 h after dosing commenced, indicates that saponins and their metabolites are not likely to be implicated in the kidney disease occurring in ruminants ingesting N. ossifragum. 相似文献
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Hyun Joo 《Pesticide biochemistry and physiology》2010,98(1):73-188
Atrazine (ATZ) metabolism by human liver microsomes (HLM), cytochrome P450 (CYP) isoforms, and human liver (HL) S9 fractions, was investigated using HPLC/PDA and LC/MS/MS. CYP-dependent metabolites from pooled HLM are desethylatrazine (DEA), desisopropylatrazine (DIA), 1-hydroxyisopropylatrazine (HIATZ), and 2-hydroxyethyl atrazine (HEATZ). DEA and DIA were major metabolites in pooled HLM. CYP1A2 and 2C19, respectively, were major isoforms for DEA and DIA production. CYP3A4, while less active, is generally at high concentrations, produces both DEA and DIA and is significant. The percent total normalized rates (%TNR) for CYP1A2 and 3A4 in pooled HLM were 63% and 24% for DEA, and 35% and 56% for DIA production. Single donor HLM samples, showed correlations for CYP1A2 (r = 0.92) and 3A4 (r = 0.81) for DEA and DIA production, while variations in production of DEA and DIA were 8.5- and 6.0-fold, respectively. Pooled S9 fractions also mediate glutathione conjugation of atrazine, DEA and DIA. 相似文献
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通过基因组粘粒文库的高通量接合转移、异源表达和生物活性测定,结合DNA序列测定,从刺孢吸水链霉菌AA97026中筛选具有广谱抗菌活性的小分子化合物及其生物合成基因簇,获得1个对革兰氏阳性细菌和红酵母均有抑制活性的阳性克隆1H5,其部分DNA序列与链丝菌素生物合成基因相似。含1H5的异源链霉菌宿主的发酵液均能检测到链丝菌素的不同组份,表明1H5含有完整的链丝菌素生物合成基因簇。 相似文献
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利用单因素试验探索了热激处理、预萌发时间、供体宿主菌的类型、供受比及MgCl_2浓度对链霉菌SH121接合转移效率的影响,结果显示:在50℃热激10min,37℃预萌发1h,以大肠杆菌DCDA/pUZ8002为供体宿主菌,在供受比为100∶1时,使用添加40mmol/L MgCl_2的培养基M-ISP4,接合转移效率最高可达到每受体1.03×10~(-3)个接合子。利用建立好的接合转移方法,将整合型质粒pSET152和基因敲除质粒pYZ09成功地导入链霉菌SH121,证实该方法可用于后期链霉菌SH121活性天然产物的挖掘及其相关生物合成基因簇的研究工作。 相似文献
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基于农药小分子人工抗原设计合成的基本原则,以氰戊菊酯的特征菊酸部分——氰戊菊酸作为半抗原,与载体蛋白BSA偶联合成了氰戊菊酯免疫特异性人工结合抗原,并对抗原合成条件进行了探索。结果表明,抗原合成反应温度以室温为宜,偶联时缓冲液的最佳pH值为8.0;通过紫外分光光度仪扫描,合成抗原的紫外图谱相对于半抗原和载体蛋白均发生了偏移,表明偶联成功;SDS-PAGE电泳结果表明,合成产物蛋白条带明显在载体蛋白条带之后,即合成产物的分子量大于相应的载体蛋白分子量,从而判定偶联是成功的。 相似文献
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莱克多巴胺人工抗原的合成与鉴定 总被引：8，自引：0，他引：8
用戊二酸酐将盐酸莱克多巴胺活化成莱克多巴胺-戊二酸酐半醛,用混合酸酐法将莱克多巴胺-戊二酸酐半醛与KLH和BSA偶联,合成免疫原和包被抗原,经核磁共振法和紫外吸收法鉴定,偶联成功.用紫外吸收法测定免疫原和包被抗原的偶联比分别为24：1和2.5：1.用免疫原免疫新西兰白兔,采用间接ELISA法检测抗体效价,采用间接竞争ELISA法检测IC50值,获得了效价为1：6 000以上、IC50值为10 ng/mL的多克隆抗体,证明合成的人工免疫原具有免疫原性. 相似文献