Escherichia coli and Staphylococcus aureus are pathogens that have the ability to form biofilms and cause disease in food products. Due to the fact that the enterotoxins produced by these two pathogens remain in a wide range of temperature, pH and saline conditions, they cause severe infections in humans. Melittin is a natural peptide derived from bee venom that can show its antimicrobial and anti-biofilm potential through disrupting the membrane of bacterial cells. For this purpose, in this study, the antimicrobial effect of this peptide on Gram positive and negative bacteria was investigated and its minimum inhibitory concentration (MIC) was determined as 100 µg/mL and 300 µg/mL, respectively. Also, the scanning electron microscope images confirmed the antimicrobial effect of the peptide on these two bacteria. Peptide melittin caused wrinkling, deformation and creation of holes in the cell membrane of treated bacteria, compared to the control sample. On the other hand, the results of the biofilm inhibition test showed that the addition of the peptide at a concentration of 2MIC completely prevented the biofilm formation of S. aureus prevented, while this value was equal to 91.00 ± 2.82 in E. coli bacteria. Also, the increase in peptide concentration caused an increase in the destruction of adult biofilms of both bacteria. On the other hand, this peptide decreased the invasion and adhesion of these two bacteria to HT-29 and Caco-2 cells by reducing the mobility of pathogens. Therefore, according to the obtained results, melittin peptide can be a suitable alternative to chemical disinfectants that are harmful to the environment.

Mitochondria contain their own DNA (mtDNA), which codes for 13 proteins (all subunits of the respiratory chain complexes), 22 tRNAs and 2 rRNAs. Several mtDNA point mutations as well as deletions have been shown to be causative in well-defined mitochondrial disorders. A mixture of mutated and wild type mtDNA (heteroplasmy) is found in most of these disorders. Inheritance of mtDNA is maternal, and mothers with heteroplasmic mtDNA transmit different proportions of normal and mutated mtDNA to the children. Mitochondrial tRNA genes have a central role in mitochondrial gene expression at the level of transcription, RNA processing and protein synthesis and they appear to be the mitochondrial genes most frequently affected by mutations causing diseases in man.

The new coronavirus was first identified in China in December 2019 and then, it created a widespread pandemic around the world. There is currently no definitive cure for it and it will not be possible to make a vaccine soon. Pathogenic mechanism of the virus includes virus entry, binding to angiotensin-converting enzyme 2 (ACE2) receptors on the surface of host cells, proliferation, membrane fusion, assembly, subsequent infection, cytokine secretion, and the host immune response to the virus. By identifying at what stage the patient is, possible effective drugs can be used to control each stage. Therefore, identifying the mechanism of action of the virus in different stages of the disease makes it possible to use the appropriate drug for each stage of the disease and control the disease.