High yellow pigments production by root culture of <Emphasis Type="Italic">Carthamus tinctorius</Emphasis> and its release in medium under gas oil treatment

In this study, the ability of safflower-isolated root cultures to produce yellow pigments was tested. Initially, the growth of isolated roots in static liquid medium was evaluated with different volumes of culture medium. A volume of 6 ml of medium per flask of 250 ml gave the best growth performance and, in this condition of culture, production of pigments from isolated roots treated or not by light has been determined by spectrophotometry (321 and 400 nm). Under these conditions, the production of yellow pigments amounted to 13.18 mg g⁻¹ fresh weight and the light stimulated the synthesis of these pigments by isolated roots. Total yellow pigments of 24.12, 38.91 and 46.38 mg g⁻¹ fresh weight was produced by the roots treated with 9, 13.5 and 18% (v/v) gas oil, respectively, representing high values of production. The pigments were released in large quantities in the medium. The increased synthesis of pigments as a result of gas oil treatment was accompanied by a reduction of the peroxidase activity of roots. Given the high production of yellow pigments, systems of isolated root culture could be considered for the study of a larger scale production of safflower pigments widely used for various industrial purposes.     

Enhanced periplasmic expression of human activin A in Escherichia coli using a modified signal peptide

Abstract

Activin A is a member of the transforming growth factor-beta (TGF-β) protein superfamily, which acts as a hormone in regulating cell proliferation and differentiation. Structurally, activin is a dimer of two subunits linked by a disulfide bond. Since the correct folding of this protein is essential for its function, we aimed to use a modified signal peptide to target the expressed recombinant protein to the periplasm of Escherichia coli as an effective strategy to produce correctly-folded activin A. Therefore, the coding sequence of native Iranian Bacillus licheniformis α-amylase signal peptide was modified and its efficiency was checked by SignalP bioinformatics tool. Then its final sequence was cloned upstream of the activin A mature cDNA. Protein expression was done using 1?mM of isopropyl thio-β-D-galactoside (IPTG) and a post-induction time of 8?hr. Additionally, following purification of recombinant activin A, circular dichroism spectroscopy was used to determine the accuracy of secondary structure of the protein. Importantly, differentiation of K562 cells to the red blood cell was confirmed by measuring the amount of Fe⁺² ions after treatment with recombinant activin A. The results indicated that the produced recombinant activin A had the same secondary structure as the commercial human activin A and was fully functional.