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Introduction: The study of the effects of synthetic peptides with antibacterial properties can provide more effective antibiotics. This study designed, expressed, and investigated the Sushi 3 tetramer peptide. Subsequently, it was compared in terms of changing antibacterial properties with another Sushi3 tetramer peptide the aspartic acid and proline amino acids of which were replaced with glycine and serine amino acids.
Material & Methods: First, the mentioned Sushi3 tetramer peptide sequences were designed, constructed, and named Mer1 and Mer 2, respectively, and cloned separately into plasmid pET-26b (+) and finally transferred to E.coli BL21 host (DE3). After the expression of the peptides, the presence of peptides was confirmed by SDS-PAGE and Western blotting. Afterward, the antimicrobial activity of Mer1 and Mer 2 was evaluated and compared. Finally, the toxicity of the two tetramers made on the MDA-MB-231 cell line was evaluated and compared.
Findings: Mer1 and Mer 2 had similar protein expression, and the toxic effect of both peptides on the cell line was not significantly different. however, Mer 2 had more effective antimicrobial effects than Mer1 at the same concentrations.
Discussion & Conclusion: Evaluation of the effect of amino acid replacement with less negatively charge on increasing the antimicrobial activity of peptides is a suitable strategy. The above results increase the possibility of designing and producing antimicrobial peptides against antibiotic-resistant strains as the next generation of antibiotics.

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Introduction: Studies have shown that an increase in carcinoembryonic antigen (CEA) is associated with the progression of colorectal cancer and is considered a sensitive diagnostic factor for CRC. Moreover, the role of peroxisome proliferators (PPARs) has recently been considered in colorectal cancer. This study aimed to investigate the relationship between the expression level of PPARs and CEA level in patients with colorectal cancer.
Material & Methods: In this study, a total of 100 samples of primary tumor tissue along with adjacent healthy tissue samples and serum samples of patients with colorectal cancer who underwent surgery were prepared from the tumor bank of Tehran Cancer Institute in Thran, Iran. The expression level of peroxisome proliferator receptors (PRARs) in tissue samples and CEA level in serum samples were measured, and the relationship between these markers was evaluated as well. The financial support for the study was provided by the Islamic Azad University (grant number 132655).
(Ethic code: 132655)
Findings: The results of this study showed a significant increase in the expression level of PPARs and serum CEA levels in patients with colorectal cancer (P<0.01). Although the level of these markers had a significant relationship with the progression and spread of disease in patients (P<0.01), no significant relationship was observed between the expression of PPARs and serum CEA in these patients (P>0.05).
Discussion & Conclusion: Based on the obtained results, the expression level of PPARs and the serum CEA level are associated with the progression and spread of the disease; however, there is no significant relationship between the expression level of PPARs and the serum CEA level in patients with colorectal cancer.