The antiviral mechanism of the crude extract from the flowers of Trollius chinensis based on TLR 3 signaling pathway.

The effects of crude extract from the flowers of Trollius chinensis on expressions of mRNA and proteins related to vital genes (TLR 3, TBK 1, IRF 3 and IFN β) in TLR 3 signaling pathway were investigated in the presence/absence of Polyinosinic acid-polycytidylic acid (PolyI: C) to ascertain the antiviral mechanism of these flowers. Real-time PCR and western blot were applied to determine the expressions of mRNA and proteins, respectively, and immunofluorescence assay was employed to study the effect on IRF 3 distribution between nuclei and cytoplasma. In the absence of PolyI:C, the crude extract reduced the mRNA expression of TLR 3, IRF 3 and IFN β and the protein expression of TLR 3, and increased the protein expression of IRF 3 and the distribution of IRF 3 in nuclei.

Enhanced Production of Crude Violacein from Glucose in Escherichia coli by Overexpression of Rate-Limiting Key Enzyme(S) Involved in Violacein Biosynthesis.

Crude violacein, consisting of violacein and deoxyviolacein, displays many attractive bio-activities in the field of drug therapy. To produce crude violacein from an industrially economic carbon source, we firstly introduced the violacein pathway into Escherichia coli B8/pTRPH1, which was previously engineered to accumulate tryptophan from glucose. A crude violacein production capacity of 0.

High crude violacein production from glucose by Escherichia coli engineered with interactive control of tryptophan pathway and violacein biosynthetic pathway.

Background: As bacteria-originated crude violacein, a natural indolocarbazole product, consists of violacein and deoxyviolacein, and can potentially be a new type of natural antibiotics, the reconstruction of an effective metabolic pathway for crude violacein (violacein and deoxyviolacein mixture) synthesis directly from glucose in Escherichia coli was of importance for developing industrial production process.

Results: Strains with a multivariate module for varied tryptophan productivities were firstly generated by combinatorial knockout of trpR/tnaA/pheA genes and overexpression of two key genes trpEfbr /trpD from the upstream tryptophan metabolic pathway. Then, the gene cluster of violacein biosynthetic pathway was introduced downstream of the generated tryptophan pathway.

Pathway redesign for deoxyviolacein biosynthesis in Citrobacter freundii and characterization of this pigment.

Violacein (Vio) is an important purple pigment with many potential bioactivities. Deoxyviolacein, a structural analog of Vio, is always synthesized in low concentrations with Vio in wild-type bacteria. Due to deoxyviolacein's low production and difficulties in isolation and purification, little has been learned regarding its function and potential applications.