Prodigiosin (Pg) is a bright red pigment, which is produced by gram negative and gram positive bacteria including Serratia marcescens, Hahella chejuensis, Vibrio psychroerythrus, Streptomyces coelicolor and many other marine bacteria such as Pseudomonas sp., Vibrio sp. Pg induces apoptosis in different kinds of cancer cells with low toxicity on normal cells. In this study, we purified Pg from solid fermentation of S. marcescens M10 strain and assessed its anticancer activity in tumorized mice. The results showed that Pg was purified by running through a silicagel 60 column with a suitable solvent system of n-hexane:toluene at the rate of 1:1 (v/v) combined with toluene:ethyl acetate at the rate of 9:1 (v/v). TLC plate was used to test the presence of active substances with separation solvent n-hexane:ethyl acetate ratio of 1:1 (v/v). The purity of fractions tested by high performance liquid chromatography method showed as 98%. Purified fractions also showed promising anti-tumor activity in Lewis lung carcinoma induced tumors in BALB/c mice. The tumor volumes in Pg treated groups decreased by 34.18% after 28 days of administration.
The study focuses on engineering of recombinant Aspergillus niger to produce highly active xylanase. The xylanase G2 encoding gene originating from Aspergillus oryzae VTCC-F187 was cloned, amplified, and inserted into the pAN7.1GluA vector with specific primers possessing BamHI. The recombinant plasmid was introduced into Aspergillus niger VTCC-F017 by chemical methods. The recombinant strain was checked by polymerase chain reaction method and Southern blot. Next, the recombinant protein was expressed and purified by His-tag column. The molecular mass of the purified xylanase G2, as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), was 21 kDa with a specific activity of 1025 IU/mg towards 0.5% (w/v) of birchwood xylan. The optimal temperature and pH were 55°C and pH 6.5, respectively. The enzyme was stable in a temperature ranges 25–40°C and a pH ranges 5–7. The presence of Tween 80 enhanced xylanase activity. Triton X-100, however, had no impact on the function of the enzyme. The xylanase activity was reduced by Tween 20, SDS, and organic solvents. The enzyme was completely inhibited by Hg2+ and partially by Zn2+, Fe2+, and Ag+, while it was slightly stimulated by K+ and EDTA.
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