再生丝心蛋白和羧甲基纤维素复合膜的特性及其在有机相 …

用再生丝心蛋白和羧甲基纤维素构成的复合膜作为固定葡萄糖氧化酶的基质，并用红外光谱测试了该复合膜的结构，用扫描电子显微镜观察了其形态。     

再生丝素与无机纳米粒子复合膜的结构与性能

用溶胶-凝胶法制备了纳米二氧化钛再生丝素复合膜,并用扫描电镜(SEM)、X射线(XRD)、热重分析(TGA、DTG)对复合丝素膜的结构与性能进行了表征。结果表明:加入纳米二氧化钛颗粒后再生丝素膜的热转变温度提高;再生丝素的结晶构象由S ilk I向S ilk II转变,结晶度增加。     

Preparation of Antibacterial Electrospun PVA/Regenerated Silk Fibroin Nanofibrous Composite Containing Ciprofloxacin Hydrochloride as a Wound Dressing

Electrospinning technique was used for the fabrication of poly （ vinyl alcohol ） （ PVA ） / regenerated silk fibrnin （ SF ） composite nanofibers, loaded with ciprofloxacin HCI （CipHCI） as a wound dressing. Electrospun PVA/SF/CipHCI composite nanofibers were stabilized against dissolving in water by heating in an oven at 155℃ for 5 min. Incorporation of CipHCi into electrospun nanofibers was confirmed by SEM and FT.IR spectra. Further the mechanical properties test illustrated that the addition of CipHCI enhanced the mechanical properties of PVA and PVA/SF nanofibers. The antibacterial activities against Escherichia coU （E. coli ） （ gram-negative ） and Staphylococcus aureus （ S. aureus ） （gram-positive） organisms were evaluated by disk diffusion method; and results suggested that electrospun PVA/CipHCI and PVA/SF/ CipHCI composite nanofibers showed a remarkable antibacterial activity.     

切变速度和Ca~(2+)对再生丝素蛋白溶液构象转变的影响

采用偏光显微镜和拉曼光谱研究了切变速度和Ca2+对再生丝素蛋白水溶液构象转变的影响.结果表明:切变速度和Ca2+是影响再生丝素蛋白溶液性质的两个主要因素,对于同一再生溶液,切变速度增大,溶液中丝素蛋白分子沿切变方向的有序排列也随之增加,丝素溶液更容易从无规线团或α-螺旋向β-折叠转变,并且转变的程度随着剪切速度的增加而加强;透析溶液中Ca2+含量增加,则样品出现偏光现象的临界切变速度有所降低.拉曼光谱显示丝素蛋白分子构象由SilkⅠ向SilkⅡ转变.     

自制聚二甲基硅氧烷/二乙烯基苯固相微萃取膜富集水样中邻苯二甲酸酯类化合物

采用湿法制膜技术制备了聚二甲基硅氧烷/二乙烯基苯(PDMS/DVB)新型固相微萃取膜,以扫描电镜、红外光谱和热重分析等手段对自制膜的性能进行表征.考察了吸附条件、解吸条件的影响,用于珠江水和湖水中邻苯二甲酸酯类化合物的分离富集.珠江水样检出3种邻苯二甲酸酯类化合物,湖水样检出5种邻苯二甲酸酯类化合物,含量在41.17～119.49μg/L之间,回收率79.6%～112.4%,RSD 12.5%～23.8%.与固相微萃取纤维相比,固相微萃取膜制作成本低、使用方便、吸附容量大,是一种有发展前景的样品前处理新技术.     

Induction of nicotine in tobacco by herbivory and its relation to glucose oxidase activity in the labial gland of three noctuid caterpillars

Tobacco Nicotiana tabacum L. is a host plant ofHelicoverpa armigera (Huibner), Helicoverpa assulta Guenee and Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae). The difference in leaf nicotine response to the feeding by these three larvae and the mechanical simulation of their feeding was examined by HPLC. Results indicated that nicotine induction was suppressed by H. armigera and H. assulta larvae feeding or by simulated damage treated with their labial glands extracts. The production of nicotine was also suppressed by the glucose oxidase from Aspergillus niger when it was treated on mechanically wounded leaf area. On the contrary, the nicotine production was stimulated by S. litura larva feeding or by simulated damage treated with its labial gland extract. Heat denature can not counteract the stimulation effect of the S. litura labial gland extracts to tobacco nicotine production. The glucose oxidase activity was detected in labial gland extracts of both H. armigera and H. assulta, but the activity in H. armigera was significantly higher than that in H. assulta. No glucose oxidase activity was detected in labial gland extracts of S. litura. It is shown that the glucose oxidase activity in labial glands of caterpillars plays an important role in the nicotine response to herbivory. The glucose oxidase was mainly contained in the labial gland of H. armigera larva, and had the highest activity at pH 7.0. D-Glucose was the optimal substrate of the glucose oxidase. Labial gland glucose oxidase activities varied daily during larval development with high activities found when larvae were actively feeding.