Objective To find methods to isolate and purify plasminogen activator (Pla) from artificial culture of Yersinia pestis. Methods Ultrasonication and urea extracting combined by ammonium sulfate salting-out were tried to extract Pla. High performance liquid chromatography(HPLC) was used to purify Pla. The first step was ion exchange and the second was gel filtration, Preparative electrophoresis was used to purify Pla, too. The enzyme activity of the isolated or purificated Pla was detected. Results Both 50% - 60% saturated ammonium sulfate deposition of supernatant of plague bacilli ultrasonication and 0 - 10% saturated ammonium sulfate deposition of supernatant of plague bacilli powder soaked by urea had three bands(Mr about 31×103, 35×103 and 37×103) and lysis rings were 6.5 and 7.2 mm in diameter respectively when the enzyme activity was detected. Pla purified by HPLC was mainly composed of three bands(Mr about 31×103, 35×103 and 37×103), occupying more than 80% of total protein weight and lysis ring was 5.0 mm in diameter. Pla purified by preparative electrophoresis mainly consisted of three bands(Mr about 31×103, 35×103 and 37×103) with other proteins of low concentration nearby, no lysis ring was detected. Conclusions Pla is collected by the methods of ultrasonication and urea extracting. Priliminary purification of Pla can be achieved by HPLC and preparative electrophoresis.

In order to reveal the properties of polar metabolome in inflammatory cells, we selected LPS-induced RAW264.7 inflammatory cell models as the carrier for the research of metabolic fingerprint analysis. In this study, an ultra performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based metabolomics protocol was optimized for the extraction of polar metabolites from RAW264.7 cell line. Then orthogonal partial least squares discriminant analysis (OPLS-DA) was used to process the metabolic data, and finally, a total of 17 metabolites were selected and identified. The results showed that MeOH-CHCl3-H2O (8∶1∶1) was chosen as the optimal extraction solvent to achieve higher number of chromatographic peaks, with the best relative extraction efficiency and stability. Comparing with the normal cells, the inflammatory cells presented an abnormal metabolism in protein, carbohydrate, nucleotide and phospholipids. In this study, a UPLC-Q-TOF/MS-based metabolomics protocol for the polar metabolites from RAW264.7 cell line was developed, which may provide important information for the study of mechanism of inflammation and the anti-inflammatory drugs.

An in vitro anti-thrombin bioassay was developed to investigate the chemical constituents which have anti-thrombin effect from the water soluble components of Salvia miltiorrhiza. Using Chromozym TH as a probe combined with ethyl acetate Semi-micro extraction was applied to measure p-nitroaniline by HPLC. According to the results, the inactivationrate of thrombin by sodium danshensu, salvianolic acid A and salvianolic acid B under a given set of conditions were 3.06%, 77.77% and 2.35%, respectively. In the water-soluble components, salvianolic acid A has a direct inhibition of thrombin, while sodium danshensu and salvianolic acid B have no significant effect on thrombin. The method is sensitive and low consumption. It can eliminate the interference absorbed for the sample itself which can be used for screening single or multiple direct antithrombin active ingredient of herbal extract.