Cloning, Expression, and Purification of the Human Synthetic Survivin Protein in Escherichia coli Using Response Surface Methodology (RSM)

Optimizing recombinant production of L-asparaginase 1 from Saccharomyces cerevisiae using response surface methodology

L-asparaginase is an essential enzyme used in cancer treatment, but its production faces challenges like low yield, high cost, and immunogenicity. Recombinant production is a promising method to overcome these limitations. In this study, response surface methodology (RSM) was used to optimize the production of L-asparaginase 1 from Saccharomyces cerevisiae in Escherichia coli K-12 BW25113. The Box-Behnken design (BBD) was utilized for the RSM modeling, and a total of 29 experiments were conducted. These experiments aimed to examine the impact of different factors, including the concentration of isopropyl-b-LD-thiogalactopyranoside (IPTG), the cell density prior to induction, the duration of induction, and the temperature, on the expression level of L-asparaginase 1. The results revealed that while the post-induction temperature, cell density at induction time, and post-induction time all had a significant influence on the response, the post-induction time exhibited the greatest effect. The optimized conditions (induction at cell density 0.8 with 0.7 mM IPTG for 4 h at 30 °C) resulted in a significant amount of L-asparaginase with a titer of 93.52 μg/mL, which was consistent with the model-based prediction. The study concluded that RSM optimization effectively increased the production of L-asparaginase 1 in E. coli, which could have the potential for large-scale fermentation. Further research can explore using other host cells, optimizing the fermentation process, and examining the effect of other variables to increase production.

In-vitro Cytotoxicity Investigations for Phytoconstituents of Saudi Medicinal Plants With Putative Ocular Effects

BACKGROUND

Metastatic secondary ocular tumors spread from systemic malignancies, including breast cancer. This study aimed to evaluate the cytotoxicity of extracts from 5 medicinal plants native to Saudi Arabia.

METHODS

For preliminary activity screening, cytotoxicity using the MTT assay and selectivity index determinations were made for medicinal plant extracts against various cancer cell-lines. The most promising extract was subjected to GC-MS analysis to determine the phytochemical composition. Clonogenic assays were performed using the most promising extract to confirm the initial results. Finally, western blot analysis was used to determine the modulation in expression of survivin and P27 suppressor genes in the human breast adenocarcinoma (MCF7) cell-line to understand the potential mechanistic properties of the active plant extract.

RESULTS

The 5 plant extracts showed various cytotoxic activity levels using IC50. The most active extract was found to be the leaves of Capparis spinosa L. (BEP-07 extract) against the MCF7 breast cancer cell-line (IC50 = 3.61 ± 0.99 μg/ml) and selectivity index of 1.17 compared to the normal human fetal lung fibroblast (MRC5) cells. BEP-07 extract showed a dose dependent clonogenic effect against the MCF7 colonies which was comparable with the effect of doxorubicin. BEP-07 extract caused a significant decrease of survivin and increase in P27 expression compared to control GAPDH at its highest dose (14 µg/ml). The GC-MS chromatogram of Capparis spinosa L. (BEP-07 extract) revealed the existence of 145 compounds, belonging to the diverse classes of phytoconstituents. Fatty acids and their derivatives represent 15.4%, whilst octadecanoic acid, 2,3-dihydroxypropyl ester was the principal component (7.9%) detected.

CONCLUSION

Leaves of Capparis spinosa L. (BEP-07 extract) exhibited a significant cytotoxic effect particularly against breast cancer cells. It exhibited this effect through survivin inhibition and via P27 upregulation. The detected phytoconstituents in the plant extract might be involved in tested cytotoxic activity, while further investigations are required to complete the drug candidate profile.

Cloning and prokaryotic expression of WRKY48 from Caragana intermedia

Caragana intermedia (C. intermedia) is a kind of drought-tolerant leguminous shrub. WRKY transcription factors are one of the largest family of transcription factors in plants and play critical regulatory roles in stress tolerance and the development of plants. In our study, CiWRKY48 was cloned from C. intermedia, analyzed using bioinformatics software, and expressed with a prokaryotic expression system. The results showed that the open reading frame (ORF) of CiWRKY48 was 1158bp, the molecular weight (MW) was 42 kDa, and its subcellular localization was in the nucleus. Additionally, fusion protein was obtained, and confirmed by western blotting. The stress resistance of the pET30a-His-MBP-CiWRKY48 transformed Escherichia coli expression strain was reduced under mannitol and salt treatment, compared with the control. Overall, our findings provided a foundation for uncovering the function of CiWRKY48.