Saman Shalibeik, Fereshte Ghandehari, Ali-Mohammad Ahadi, Ali-Asghar Rastegari, Mojgan Ghiasian,
Volume 16, Issue 3 (May-Jun 2022)
Abstract
Background and objectives: Bacteriocins are generally active antimicrobial peptides effective against bacteria closely related to the producer. Escherichia coli produce two bacteriocins: colicins and microcins. Microcin J25 (Mcc J25) is an antibacterial peptide that inhibits bacterial transcription by disrupting the nucleotide-uptake channel of bacterial RNA polymerase. The objective of this study was to evaluate antimicrobial activity of MccJ25 produced by the bacteriocinogenic E. coli.
Methods: In this experimental study, 120 clinical specimens were selected from private diagnostic laboratories in Isfahan (Iran) in 2020. Antagonistic activity of isolates was tested by adopting agar plug method. Total DNA was extracted from clinical specimens and polymerase chain reaction (PCR) was performed using specific primers for amplification of the complete sequence of MccJ25 gene. Accuracy of the PCR products was confirmed by direct sequencing. Homology analysis was performed by using BLAST. Data were analyzed with Chromasv2.1.1 software.
Results: Overall, 120 E. coli strains were isolated from the clinical specimens. The antibiotic activity of Mcc J25 was mainly directed at Enterobacteriaceae, including several pathogenic E. coli strains of which 25 had positive well test samples, and about 5 (20%) of the collected clinical samples that were infected with E. coli had the MccJ25 gene.
Conclusions: Based on the results, Mcc J25 has favorable antibacterial potential, which can be further exploited as an alternative to chemical antibiotics.
Mahnoosh Fatemi, Fereshte Ghandehari , Danial Salehi, Parastoo Torabian,
Volume 17, Issue 6 (Nov-Dec 2023)
Abstract
Background: Discovering new cytotoxic compounds has received significant attention due to the rise in drug resistance and the adverse effects associated with chemotherapy drugs. In this study, the cytoplasmic extract of Lactobacillus casei was used to produce iron oxide nanoparticles (Fe2o3 NPs), and the cytotoxic effects of NPs were investigated on MCF-7 and human embryonic kidney 293 (HEK-293) cells.
Methods: The cytoplasmic extract of L. casei was mixed with 103M iron sulfate solution and incubated for 3 weeks at 37 °C and 5% CO2. The coprecipitation method was used to synthesize chemical Fe2o3 NPs. The synthesis of NPs was studied by electron microscopy and X-ray diffraction (XRD) analysis, and the cytotoxic effects were evaluated with dilutions (10, 100, and 1000 µg/mL) on MCF-7 and HEK cells.
Results: X-ray diffraction analysis and scanning electron microscopy presented the mean of NPs synthesized by the green method to be about 15 nm and their shape to be spherical, as well as the average of chemically synthesized NPs to be about 20 nm with cubic structure. Chemical and green synthesized NPs only at a concentration of 1000 µg/mL were able to significantly reduce the survival rate of normal HEK-293 cells; chemically synthesized NPs decreased MCF-7 cell survival only at 1000 µg/mL and green synthesis at 100 µg/mL and 1000 µg/mL.
Conclusion: Generating Fe2o3 NPs is biologically safe using the green synthesis method and the cytoplasmic extract of L. casei, which may be a suitable candidate for the treatment of cancer cells.
