应用多样性增量结合二次判别分析(Increment of Diversity with Quadratic Discriminant analysis,IDQD)方法,对大肠杆菌σ70启动子进行识别。使用受试者操作特性(receiver operating characteristic,ROC)曲线和精度召回率曲线(Precisio...应用多样性增量结合二次判别分析(Increment of Diversity with Quadratic Discriminant analysis,IDQD)方法,对大肠杆菌σ70启动子进行识别。使用受试者操作特性(receiver operating characteristic,ROC)曲线和精度召回率曲线(Precision Recall Curves,PRC)进行性能评估。10-fold交叉检验给出,在正负集之比为1∶1时,ROC曲线下面积和PRC曲线下面积均为95%。结果表明,IDQD算法有能力应用于原核启动子的识别。识别精度高于现有算法。展开更多
本文采用水热法制备了甲壳素(Chitin)和石墨相氮化碳(g-C3N4)复合材料Chitin-CN,并采用XRD、SEM、XPS、光电流及阻抗分析等手段对其进行物化特性分析.与g-C3N4相比,Chitin-CN复合材料的光生电子-空穴对的分离效率较高,甲壳素(Chitin)含...本文采用水热法制备了甲壳素(Chitin)和石墨相氮化碳(g-C3N4)复合材料Chitin-CN,并采用XRD、SEM、XPS、光电流及阻抗分析等手段对其进行物化特性分析.与g-C3N4相比,Chitin-CN复合材料的光生电子-空穴对的分离效率较高,甲壳素(Chitin)含量为0.2 g的Chitin-CN材料在模拟太阳光照射下对大肠杆菌K-12表现出最佳的光催化杀菌效率,在2 h内可完全杀死6.5 lg cfu·mL-1的大肠杆菌K-12.Chitin-CN的破碎结构暴露了更多的活性位点,甲壳素的加入提高了光生载流子的分离率,从而促进了复合材料光催化杀菌的性能.捕获实验表明超氧自由基(·O-2)和空穴(h+)是Chitin-CN作用于大肠杆菌K-12的主要活性物种.展开更多
Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL...Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL, 2μL）, immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors ofphospholipase A2 （dexamethasone）, cyclo- oxygenase （indomethacin, ibuprofen and piroxicam）, dual cyclo-oxygenase/lipoxygenase （phenidone） and lipoxygenase （esculetin） and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection （5 nodules/larva）, and increased to a maximum after 8 h （with 15 nodules/larva）, and then significantly reduced over 24 h （9 nodules/larva）. The inhibitory influence of dexamethasone was apparent within 2 h of injection （4 vs. 5 nodules/larva）, and nodulation was significantly reduced, compared to control, over 24 h （5 vs. 8 nodules/larva）. Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. rnegacephala.展开更多
文摘本文采用水热法制备了甲壳素(Chitin)和石墨相氮化碳(g-C3N4)复合材料Chitin-CN,并采用XRD、SEM、XPS、光电流及阻抗分析等手段对其进行物化特性分析.与g-C3N4相比,Chitin-CN复合材料的光生电子-空穴对的分离效率较高,甲壳素(Chitin)含量为0.2 g的Chitin-CN材料在模拟太阳光照射下对大肠杆菌K-12表现出最佳的光催化杀菌效率,在2 h内可完全杀死6.5 lg cfu·mL-1的大肠杆菌K-12.Chitin-CN的破碎结构暴露了更多的活性位点,甲壳素的加入提高了光生载流子的分离率,从而促进了复合材料光催化杀菌的性能.捕获实验表明超氧自由基(·O-2)和空穴(h+)是Chitin-CN作用于大肠杆菌K-12的主要活性物种.
文摘Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL, 2μL）, immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors ofphospholipase A2 （dexamethasone）, cyclo- oxygenase （indomethacin, ibuprofen and piroxicam）, dual cyclo-oxygenase/lipoxygenase （phenidone） and lipoxygenase （esculetin） and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection （5 nodules/larva）, and increased to a maximum after 8 h （with 15 nodules/larva）, and then significantly reduced over 24 h （9 nodules/larva）. The inhibitory influence of dexamethasone was apparent within 2 h of injection （4 vs. 5 nodules/larva）, and nodulation was significantly reduced, compared to control, over 24 h （5 vs. 8 nodules/larva）. Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. rnegacephala.
