Research progress on quality control methods of traditional Chinese medicine glues / 中国中药杂志

Traditional Chinese medicine( TCM) glues,including leather glues,horn glues,nail glues and bone glues,have a long application history and unique characteristics. In recent years,their market demand has increased year by year because of their remarkable curative efficacy and nourishing effects,which leads to insufficient supply of raw material resources,and widespread use of fake and inferior products,seriously affecting the reputation of TCM glues and drug safety. In this context,the establishment of a more specific quality detection method for the TCM glues according to their specific characteristics can effectively improve the quality control level,promote rational use,and have a far-reaching impact on the industrial development of TCM glues. In this paper,the classification of TCM glues,as well as the production and application status of their representative( Ejiao) were briefly introduced; the papers on quality control technologies of TCM glues,including traditional identification experience,authenticity identification,physical property determination,protein,peptide and amino acid contents determination,element analysis,biological evaluation,and brand protection technology of TCM glues,were reviewed,and their advantages and disadvantages were summarized and analyzed comprehensively.Based on the specific characteristics of TCM glues,such as complex material basis,unclear pharmacodynamic components and different production processes,it was proposed in this paper to research and develop information-rich,convenient,fast,and non-destructive analytical techniques for the quality control of TCM glues and brand protection of famous products,thus promoting the healthy development of TCM glues industry.

Construction of NIRS-based total quality control system for compound Ejiao oral liquid and relative thinking / 中国中药杂志

In this paper, near infrared spectroscopy (NIRS)-based total quality control system of compound Ejiao oral liquid is introduced briefly, including the quality control of raw traditional Chinese medicine (TCM) materials, monitoring and control of the extract and the alkaline precipitation technics, and also the inspection of finished products in both open bottle and non-opening modes. By analyzing and summing up the significance and difficulties, several important problems in the practical applications of NIRS technology are proposed, which will provide references for the similar studies of other TCM products.

Study on action mechanism of adjuvant therapeutic effect compound Ejiao slurry in treating cancers based on network pharmacology / 中国中药杂志

Recently, compound Ejiao slurry (FFEJJ) had been applied to treat cancer patients in clinic, with obvious curative effect. In this study, data and literatures were collected from the TCM chemical component database to establish the chemical component database of FFEJJ. Afterwards, MetaDrug software was used to predict the targets of FFEJJ and obtain the compound-target network. Next, the compound-target network was compared and analyzed to obtain the "compound-target-tumor target" heterogeneous network. Besides, further analysis was made on gene functions and metabolic pathway. The results indicated that FFEJJ could directly resist tumors by regulating cancer cell differentiation, growth, proliferation and apoptosis, and show an adjuvant therapeutic effect by enriching the blood and increasing the immunity.

Expression and Purification of Receptor Tyrosine Kinase PDGFR? / 微生物学通报

A fusion expression vector pPIC3.5K-PDGFR? was constructed to express recombinant receptor tyrosine kinase PDGFR? and the right Pichia pastoris transformants were screened on his-deficient plates and YPD-G418 plates by turns after electroporation of strain GS115, a high yield strain named M3 was screened. The strain M3 was cultured in a 5 L fermentor and His-GFP-PDGFR? fusion protein was purified by Ni2+ chelating affinity chromatography. One distinct peak was obtained after elution with 250 mmol/L imidazole. Fusion protein was proved to be 90.08 kD by western blotting, and have tyrosine kinase activity by ELISA. Results showed that the receptor tyrosine kinase PDGFR? was successfully expressed in P. pastoris and could be used as a target for small molecule selective inhibitors screening.

Construction of Hexose Transporter-like HXT1 Deletion Mutant in Pichia pastoris / 微生物学通报

Glucose was transported by the large number of hexose transporters in yeast cells. There were 18 hexose transporter genes had been identified in Saccharomyces cerevisiae. However,as an excellent expression system,there was no information of these genes had been reported in Pichia pastoris. Based on high homologous recombination efficiency in yeast,we chose G418 resistance for screening,200 bp were cloned from the up and down sequences of HXT1 ORF respectively,then ligated to the 5′ and 3′ end of G418 resis-tance gene for recombination. After electroporation of GS115 spheroplast and screened through different G418 concentration plates,finally we obtained one HXT1 gene deletion mutant named GS115?HXT1. The growth rate and glucose consumption of this mutant were both lower than the wide type.

Effect of Specific Growth Rate and Nitrogen Source on the Production of Recombinant Lateolabrax japonicus Growth Hormone by Pichia pastoris / 微生物学通报

The bioreactor production of recombinant Lateolabrax japonicus growth hormone (rljGH) expressed intracellularly by Pichia pastoris was investigated. A strategy of feeding methanol at the exponential rate was established and the effect of specific growth rate on the rljGH production was examined. The results indicated that the average specific production rate increased and the rljGH production duration decreased as the specific growth rate increased. The maximum specific rljGH production (0.58 mg/g WCW) was achieved at a specific growth rate of 0.029/h. The effect of supplementing ammonium sulfate, peptone and yeast ex- tract on the rljGH production was further investigated. The results indicated that the effects of ammonium sulfate and peptone were not significant. Supplementing yeast extract of 2.5 g/L was advantageous for the rljGH production. The duration of the rljGH production was increased to 23 h from 17 h and the fermenta- tion stability of run-to-run could be improved.

Expression and Purification of Receptor Tyrosine Kinase ErbB2 Kinase Domain / 微生物学通报

The kinase domain of receptor tyrosine kinase(RTK) ErbB2 was expressed fused with GFP in Pichia pastoris. Recombinant expression vector pPIC3.5K was constructed in Escherichia coli TOP10. The right P. pastoris transformants were screened on his-deficient plates and YPD-G418 plates by turns after electroporation of recombinant vector, and then induced by methanol in baffled shake bottles. The strain with highest protein yield was scaled up in a 5 L fermentor. Recombinant protein was analyzed with tyrosine kinase assay after Ni2+ affinity chromatograph. Results showed that the 100 kD recombinant protein with tyrosine kinase activity was successfully expressed in P. pastoris.

Detection of intracellular reactive oxygen species by flow cytometry in Pichia pastoris fermentation / 生物工程学报

In Pichia pastoris fermentation, methanol was oxidized into carbon oxide and produced a byproduct H2 O2, one of the partially reduced forms of molecular oxygen known as reactive oxygen species (ROS) . ROS are highly damaging towards cellular constituents. Flow cytometry (FCM) is an excellent method that permits the rapid, optical analysis of individual cells and has many advantages over conventional cytometry. However, its use in detecting intracellular ROS levels during Pichia fermentation was rarely reported. In our work, by means of flow cytometry, two fluorescent dye 2', 7'-dichlorofluorescin diacetate (DCFH-DA) and propidium iodide (PI) were used to detect ROS. The effect of intracellular ROS on Pichia pastoris cells during fermentation was studied through the comparison between DCFH-DA/PI double-stained cells and PI single-stained cells. In this study, the loss of cell viability during fermentation was correlated with the accumulation of ROS. At the glycerol batch and fed-batch phase, little ROS was accumulated intracellularly and cell viability reached almost 100%. At the early methanol fed-batch phase, intracellular ROS accumulation took place but 98.5% cells still kept viable. At the later methanol fed-batch phase, 94.0% cells accumulated high ROS. As a result, some cells lost their viability because of the damage of ROS. 25.4% dead cells accumulated high ROS in the total 29.1% dead cells.

Fermentation behaviors of recombinant Pichia pastoris under inhibited methanol concentration / 生物工程学报

Chemostat culture was performed to characterize the growth, substrate consumption and the hirudin production, and to disclose their interrelations in the fermentation of recombinant Pichia pastoris. The Andrew substrate-inhibited growth model is more suitable than Monod model to simulate the growth of Pichia pastoris on methanol. Therefore, two stationary states can be obtained in the continuous culture at a certain dilution rate because of the substrate inhibition on cell growth. The stationary state could be obtained if only the dilution rate not more than 0.048 h(-1) in the continuous fermentation. The concentrations of cell, methanol and hirudin were constant after 50 h continuous culture with dilution rate at 0.04 h(-1). However, it could not be obtained when the dilution rate more than 0.048 h(-1) because the other stationary point at S > 0.048 h(-1) is unstable. Therefore, it was found that the cell concentration declined and the methanol concentration increased from 2.9 g/L to 18.1 g/L within 18h at dilution rate 0.06 h(-1). Thus, the fed-batch culture with a constant specific growth rate was carried out to disclose the fermentation behavior at high and constant methanol concentration in aid of a methanol sensor. The theoretical maximum specific growth rate, microm = 0.0464 h(-1), was found under critical methanol concentration, Scrit = 3.1 g/L. The growth of P. pastoris was typically methanol-limited at the methanol concentration S < Scrit. It was, however, inhibited at S > Scrit. The maximum specific Hir65 production rate qp was obtained at 0.2 mg/(g x h) when methanol concentration and mu were 0.5 g/L and 0.02 h(-1), respectively. The specific Hir65 production rate qp increased with the increase of mu and S at mu < 0.02 h(-1), and decreased at mu > 0.02 h(-1). The specific methanol consumption rate increased with the increase of S when S < 5 g/L, but decreased when S > 5 g/L. At last, the high Hir65 production rate 0.2 mg/(g x h) was obtained in the fermentation conducted under methanol-limited concentration and mu controlled at 0.5 g/L and 0.02 h(-1), respectively, while the specific methanol consumption rate is low only at 0.04 g/(g x h), showing the potential for the strategy of getting high Hir65 production rate at the low consumption of methanol.

Effects of different methanol feeding strategy on hirudin production in high-density fermentation by recombinant Pichia pastoris / 生物工程学报

Four different methanol feeding modes were evaluated in the hirudin production in high-density fermentation by Pichia pastoris. It was difficult to avoid methanol excessive in the broth with the feeding strategy only based on DO level. On the other hand, the fluctuation in methanol concentration was observed with methanol feeding strategy by off-line gas chromatography. However, the stable methanol concentration was perfectly achieved by the on-line monitoring with methanol sensor. The supply of energy was improved by feeding glycerol at a limited rate as well as methanol in the induction phase. Therefore, the high cell dry weight (162 g/L) and high hirudin activity (2.4 x 10(4) ATU/mL or 1.7 g/L) was obtained in the fed-batch fermentation of recombinant Pichia pastoris by methanol-glycerol mixed feeding.

Application of Direct Gene Disruption Method in Recombinant Pichia pastoris / 微生物学通报

Proteolytic degradation has been a severe problem when Pichia pastoris is employed to express recombinant proteins.One alternative method to circumvent this problem is to construct protease gene disruptant.However,the main study of gene disruption is focused on nonrecombinant Pichia pastoris rather than recombinant strain.In our study,we established two different methods to directly disrupt PRC1 and KEX1 gene in recombinant Pichia pastoris.On the basis of this,we further discussed and compared the application and advantages of both methods.

Application of Flow Cytometry in Viability Detection of Pichia pastoris Cells / 微生物学通报

Cell viability of Pichia pastoris was detected by flow cytometry (FCM) with two reagents fluorescein diacetate (FDA) and propidium iodide (PI). Compared with FDA/PI double-stained dot plots and PI single-stained dot plots,the latter could divide dead and living cells into two separate zones,and get the correct proportion. Then PI single-stained method was used to detect the change of cell viability in Pichia patoris fermentation. At glycerol batch and fed-batch phase,little dead cells were detected. At methanol fed-batch phase,cell viability decreased when cell weight increased,and was only 73.8% at 88 h.