Objective To evaluate the inhibitory activity of Herba Taraxaci extract on Escherichia coli DH5α (E. coli DH5α) and to investigate proteomic response of E. coli. Methods Medicinal powder of Herba Taraxaci was extracted with the solvents of different polarity ( n-hexane, ethyl acetate, distilled water) , and then the obtained 8 different extracts were subjected to thin layer chromatography ( TLC) analysis. Microdilution method was performed to detect the minimum inhibitory concentration ( MIC) of different extracts and the growth curves were described. The protein expression profiles of E . coli treated with the extracts were analyzed by sodium dodecyl sulfate polyacrylamide gel electropheresis ( SDS-PAGE) and two dimensional electrophoresis (2-DE) . Results Water decoction of Herba Taraxaci could obviously suppress the growth of E. coli with a MIC of 1.95 mg/mL. The different extractions exhibited no antibacterial activity except ethyl acetate phase 3 with a MIC of 0.13 mg/mL, which was equal to 19.23 mg/mL of crude drugs. The results of TLC analysis showed that chlorogenic acid was undetectable in n-hexane extract and ethyl acetate phase 1 extract, and ethyl acetate phase 2 and 3 extracts showed obviously increased spots. The results of SDS-PAGE and 2-DE showed that water decoction of Herba Taraxaci had inhibitory effect on the expression of functional protein. The results of 2-DE showed that after treatment with ethyl acetate phase 3 at the concentration of 2 × MIC for 21 hours, the amount of protein spots were 92 less than those of the blank control group, the spots of E. coli DH5α soluble protein with expression amount down-regulated doubly were 24, and those with expression amount up-regulated doubly were 19. Ethyl acetate phase 3 extract had an effect on down-regulating the protein expression of E. coli DH5α soluble protein pH3-10, and water decoction of Herba Taraxaci had inhibitory effect on E. coli DH5αprotein expression. Conclusion Herba Taraxaci has significant antibacterial activity on E. coli DH5α, and the water-soluble fraction of chlorogenic acid and caffeic acid might be the active components. The possible antibacterial mechanism may be related with the regulation of bacterial protein expression.

Objective To study the effect and potential mechanism of Chaihuang Yishen Granules on renal fibrosis in mice with chronic kidney disease.Methods Thirty-six C57BL/6 male mice were randomly divided into sham group,model group,low-,and high-dose Chaihuang Yishen Granules groups(3.835 g·kg-1 and 7.67 g·kg-1),positive control group and Mincle ligand trehalose-6,6-dibehenate(TDB 10 mg·kg-1)group.Unilateral ureteral obstruction(UUO)was used to establish the model of renal fibrosis in mice.One hour after operation,mice in each drug-treated group were given corresponding drugs by gavage,and sham operation group and model group were given saline by gavage,once a day for 7 consecutive days.The pathological changes and fibrosis in the kidneys of mice in all groups were observed by hematoxylin eosin staining and Sirius red staining.The expressions and secretions of inflammatory factor IL-1β,IL-6 and TNF-α in kidneys of all groups were detected by Real-time PCR and ELISA.Immunohistochemistry and Western Blot were used to detect fibrosis indicators,including α-SMA and Fn protein levels.Immunofluorescence and Western Blot were further used to determine protein levels of Mincle and its downstream signal Syk/NF-κB.The proportion of Mincle positive macrophages was analyzed by flow cytometry.Results Compared with the model group,low-and high-dose Chaihuang Yishen Granules can effectively improve UUO-induced renal injury and fibrosis,and inhibit α-SMA and Fn protein levels in the kidney(P＜0.01).Moreover,high-dose Chaihuang Yishen Granules can effectively reduce the expressions and secretions of inflammatory factor IL-1β,IL-6 and TNF-α of kidney in UUO model(P＜0.01),as well as inhibit phosphorylation of NF-κB(P＜0.01).The mechanism study showed that Chaihuang Yishen Granules could significantly reduce the protein level of Mincle and the activity of its downstream signal Syk in the kidney of UUO mice(P＜0.01).After TDB was used to activate Mincle,the effect of Chaihuang Yishen Granules on improving renal injury,inflammatory factor secretion and fibrosis was significantly reduced(P＜0.05,P＜0.01).Conclusion Chaihuang Yishen Granules can improve UUO-induced renal injury,inflammation and fibrosis,and its mechanism may be related to the down-regulation of Mincle/Syk/NF-κB signaling pathway.

Acid protease, an important aspartic protease, has been widely used in food, pharmaceutical and tanning industries. To promote the research and application of acid protease, an acid protease gene (pepA) from Aspergillus oryzae was obtained from fermented soy based on metagenome sequencing, and then cloned and transformed into Pichia pastoris GS115 for heterologous expression. The characteristic of recombinant PepA was also investigated. The activity of acid protease in the culture supernatant of P. pastoris was 50.62 U/mL. The molecular mass of PepA was about 50 kDa, and almost no other proteins in the supernatant were observed, as shown by SDS-PAGE. The optimum pH and temperature of PepA were determined as pH 4.5 and 50 ℃. Mn²⁺ and Cu²⁺ enhanced the activity of PepA, whereas Fe³⁺, Fe²⁺ and Ca² had inhibitory effects on its activity. The above findings can provide guidance for heterologous expression and industrial application of acid protease from Aspergillus oryzae.
Aspergillus oryzae ; Cloning, Molecular ; Endopeptidases ; Hydrogen-Ion Concentration ; Pichia ; Recombinant Proteins ; Temperature